ALBERT

Notizen: 1 Our previous report showed that in acute cholestasis, the subsensitivity to morphine inhibitory effect on electrical-stimulated contractions develops significantly faster in guinea-pig ileum (GPI) and in mouse vas deferens (MVD) (45.2 and 29.9 times, respectively) compared with non-cholestatic subjects. 2 The possible contribution of α2-adrenoceptor and nitric oxide (NO) pathways on the development of tolerance was assessed in GPI and MVD of cholestatic subjects. 3 Daily administration of naltrexone (20 mg kg−1), yohimbine (5 mg kg−1), and Nω-nitro-l-arginine methyl ester (l-NAME) (3 mg kg−1) to cholestatic animals significantly (P-value 〈 0.05) inhibited the process of subsensitivity in all groups. 4 Consistent with the literature, it was concluded that both the α2-adrenergic system and NO have close interaction with the opioid system and may underlie some of the mechanisms involved in the subsensitivity development to opioids in acute cholestatic states.

Notizen: 1 We examined the role of the NO/cyclic GMP (cyclic GMP) pathway in nitric oxide (NO)- and vasoactive intestinal peptide (VIP)-induced relaxation of feline lower oesophageal sphincter (LES). Furthermore, it was studied whether methylene blue, LY83583 and ODQ, which are soluble guanylate cyclase (sGC) inhibitors, could inhibit NO-induced relaxation.2 The nitric oxide synthase (NOS) inhibitor, N-nitro-l-arginine (l-NNA) had no effect in sodium nitropruside (SNP)-induced relaxation, but 3-morpholinosydnonimine-N-ethylcarbamide (SIN-1)-induced relaxation was decreased by the pretreatment of l-NNA, which showed that SIN-1, not SNP, could activate NOS to cause relaxation. Methylene blue and LY83583 did not inhibit the relaxation by SNP and SIN-1. However, the more specific sGC inhibitor ODQ blocked the relaxation induced by NO donors.3 To identify the relationship of NOS, sGC and adenylate cyclase in VIP-induced relaxation, tissue were pretreated with l-NNA and ODQ and SQ22536. These inhibitors produced significant inhibition of this response to VIP. The adenylyl cyclase inhibitor SQ 22536 also inhibited relaxation by VIP.4 In conclusion, our data showed that SNP- and SIN-1-induced relaxation was mediated by sGC. Of sGC inhibitors, methylene blue and LY83583 were not adequate for the examination of NO donor-induced feline LES smooth muscle relaxation. VIP also caused relaxation by the pathway involving NO and cGMP and cAMP.

Notizen: 1 The vasoconstrictor response to periarterial nerve electrical stimulation (PNS) and neurotransmission by ATP are discussed and illustrated, using canine isolated and perfused splenic arterial preparations. 2 The conditions for appearance of dominant purinergic constrictor response to PNS are discussed. 3 Modulation of the purinergic vasoconstrictor responses to PNS by several kinds of presynaptic receptor agonists and antagonists is reviewed. 4 Influences of purinergic responses to PNS by guanethidine, reserpine, tetrodotoxin (TTX) or ω-conotoxin GVIA (ωCTX) are also reviewed. 5 Effects of imipramine and removal of the endothelium are discussed. 6 Evidence is presented for selective inhibition of purinergic responses to PNS by an adequate cold storage of the vessel. 7 The roles of ATP released by PNS in isolated canine splenic arteries are proposed.

Notizen: 1 The aim of the present study was to investigate the role of several possible neurotransmitters in mediating non-adrenergic, non-cholinergic (NANC) relaxation, and the effects of phosphodiesterase (PDE) III and V inhibitors on adrenergic and NANC relaxation in branch pulmonary artery (PA) of guinea-pig. 2 Under the NANC conditions, electrical field stimulation (EFS, 60 V, 0.2 ms, 20 Hz) induced a tetrodotoxin-sensitive relaxation of the histamine-precontracted PA rings. The nitric oxide (NO) synthase inhibitor NG-nitro-l-arginine methyl ester (l-NAME, 10−4 m) and the guanylyl cyclase inhibitor 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ, 10−5 m) partially inhibited the EFS-induced relaxation. The inhibitory effect of l-NAME was reversed completely by l-arginine (10−3 m), but not d-arginine (10−3 m). 3 This NANC relaxation was attenuated by 8-phenyltheophylline (10−5 m), a P1-purinoceptor antagonist. 4 The NANC response was potentiated by 10−6 m zaprinast, a type V PDE inhibitor, but was unaffected by 3 × 10−6 m milrinone, a type III PDE inhibitor. 5 Sodium nitroprusside (SNP) caused a concentration-dependent vasodilator effect which was potentiated by zaprinast, but unaffected by milrinone. Moreover, the effect of combination of zaprinast with milrinone was not significantly different from that observed with zaprinast alone. 6 Isoprenaline produced a concentration-dependent vasodilatation in branch PA of guinea-pig which was potentiated by both zaprinast and milrinone, the efficacy of milrinone being greater than zaprinast. 7 These results suggest that both nitrergic and purinergic pathways are involved in mediating the NANC relaxation in branch PA of guinea-pig. The combination of PDE III or V inhibitors with vasorelaxant drugs may be a hopeful approach for the treatment of pulmonary hypertension.

Notizen: 1 The present survey is dealing with the interactions between the renin–angiotensin–aldosterone system (RAAS) and the sympathetic nervous system (SNS) in various organs and tissues, with an emphasis on the angiotensin AT-receptors located at the sympathetic nerve endings. 2 Angiotensin II, the main effector of the RAAS is known to stimulate sympathetic nerve traffic and its sequelae in numerous organs and tissues, such as the central nervous system, the adrenal medulla, the sympathetic ganglia and the sympathetic nerve endings. These stimulatory effects are mediated by AT1-receptors and counteracted by AT1-receptor antagonists. 3 Sympatho-inhibition at the level of the sympathetic nerve ending appears to be a class effect of the AT1-receptor blockers, mediated by presynaptic AT1-receptors. With respect to the ratio pre-/postsynaptic AT1-receptor antagonism important quantitative differences between the various compounds were found. 4 Both the pre- and postjunctional receptors at the sympathetic nerve endings belong to the AT1-receptor population. However, the presynaptic receptors belong to the AT1B-subtype, whereas the postjunctional receptors probably belong to a different AT1-receptor subpopulation. 5 Sympatho-inhibition is a class effect of the AT1-receptor antagonists. In conditions in which the SNS plays a pathophysiological role, such as hypertension and congestive heart failure, this property may well be of therapeutic relevance.

Notizen: 1 The psychostimulant constituent of khat leaves, S-(−)-cathinone, was examined for vascular activity on the coronary vasculature of guinea-pig-isolated perfused hearts and aortic ring preparations. 2 Cathinone caused coronary vasoconstriction, negative inotropy and negative chronotropy in isolated hearts. The major metabolite of cathinone after its ingestion, 1R.2S-(−)-norephedrine (norephedrine), also caused coronary vasoconstriction comparable with that by cathinone. Norephedrine, however, had no effect on force or rate of cardiac contractions. 3 Cocaine (10 μm) potentiated the coronary vasoconstriction and positive inotropy by noradrenaline indicating inhibition of neuronal uptake. The vasoconstriction and negative inotropy by cathinone, however, were not affected, indicating that its action was not via release of noradrenaline from sympathetic neurones. 4 The α1-adrenoceptor antagonist, prazosin, blocked the vasoconstriction by noradrenaline, but not that produced by cathinone in the presence of cocaine. This indicates that the coronary vasoconstriction by cathinone was not due to an action on α1-adrenoceptors either directly or indirectly through noradrenaline release. 5 Three repeated doses of cathinone displayed the same coronary vasoconstrictor responses, indicating a lack of tachyphylaxis and therefore confirming that the response was unlikely to be due to indirect sympathomimetic activity through release of noradrenaline. 6 In guinea-pig aortic rings, the order of vasoconstrictor activity was: noradrenaline 〉 norephedrine 〉 cathinone, with each causing approximately equivalent maximum responses. The time to reach plateau contractions was shortest for noradrenaline (5.1 ± 0.5 min), then norephedrine (9.3 ± 1.5 min) and cathinone the longest (25.4 ± 3.2 min, 335 μm dose). 7 These results indicate that cathinone has vasoconstrictor activity which is not due to indirect or direct sympathomimetic activity. The precise mechanism for this vasoconstriction remains to be determined. The coronary vasoconstriction may explain the increased incidence of myocardial infarction in khat chewers, which may arise from coronary vasospasm.

Notizen: 1 A variety of prostanoids were examined for their ability to alter the periarterial nerve stimulation-induced release of noradrenaline (NA) and neuropeptide Y immunoreactive compounds (NPY-ir) from the perfused mesenteric arterial bed of the rat. 2 Periarterial nerve stimulation (16 Hz) increased the overflow of NA, NPY-ir and perfusion pressure. 3 The prostacyclin (PGI2) analogues, carbaPGI2 and cicaprost both produced a concentration-dependent attenuation of the nerve stimulation-induced increase in NA, NPY-ir overflow and perfusion pressure. 4 The prostaglandin (PG) analogue PGE2 attenuated the evoked increase in NPY-ir overflow as well as a modest decrease in NA. 5 PGE1, sulprostone and iloprost attenuated the nerve stimulation-induced increase in NA overflow but not NPY-ir. 6 Neither PGF2α nor the thromboxane A2 analogue U46619 altered the evoked increase in NA or NPY-ir overflow. 7 The results support the view that sympathetic co-transmitter release can be differentially modulated by paracrine/autocrine mediators at sympathetic neuroeffector junctions.

Notizen: 1 Experiments were undertaken to determine if the imidazoline/α2-adrenoceptor agonist, rilmenidine, would produce mydriasis in cats and, if so, to delineate its site of action and determine if this effect is mediated by imidazoline receptors or α2-adrenoceptors. 2 Rilmenidine produced dose-related pupillary dilator responses in pentobarbital anaesthetized cats that were independent of sympathetic innervation to the iris but were dependent upon intact parasympathetic neuronal tone. The ED50 for rilmenidine-induced pupillary dilation was approximately 200 μg kg−1, i.v., and was sustained for at least 1 h. 3 The highly selective α2-adrenoceptor antagonist, RS-79948, administered either before or after rilmenidine, antagonized rilmenidine-induced mydriasis. Neuronally induced reflex inhibition of parasympathetic nerve activity was also inhibited by administration of RS-79948. 4 These results suggest that rilmenidine acts like clonidine to produce pupillary dilation by inhibition of parasympathetic tone to the iris sphincter and that this central nervous system parasympatho-inhibition is mediated by α2-adrenoceptors, rather than imidazoline receptors.

Notizen: 1 Increasing evidence indicates the occurrence of functional interconnections between immune and nervous systems, although data available on the mechanisms of this bi-directional cross-talking are frequently incomplete and not always focussed on their relevance for neuroimmune modulation.
2 Primary (bone marrow and thymus) and secondary (spleen and lymph nodes) lymphoid organs are supplied with an autonomic (mainly sympathetic) efferent innervation and with an afferent sensory innervation. Anatomical studies have revealed origin, pattern of distribution and targets of nerve fibre populations supplying lymphoid organs.
3 Classic (catecholamines and acetylcholine) and peptide transmitters of neural and non-neural origin are released in the lymphoid microenvironment and contribute to neuroimmune modulation. Neuropeptide Y, substance P, calcitonin gene-related peptide, and vasoactive intestinal peptide represent the neuropeptides most involved in neuroimmune modulation.
4 Immune cells and immune organs express specific receptors for (neuro)transmitters. These receptors have been shown to respond in vivo and/or in vitro to the neural substances and their manipulation can alter immune responses. Changes in immune function can also influence the distribution of nerves and the expression of neural receptors in lymphoid organs.
5 Data on different populations of nerve fibres supplying immune organs and their role in providing a link between nervous and immune systems are reviewed. Anatomical connections between nervous and immune systems represent the structural support of the complex network of immune responses. A detailed knowledge of interactions between nervous and immune systems may represent an important basis for the development of strategies for treating pathologies in which altered neuroimmune cross-talking may be involved.

Notizen: 1 Calcium/calmodulin-dependent protein kinase II (CaMKII) has an important function in mediating insulin release but its role in the development of diabetes-induced cardiovascular complications is not known. 2 We investigated the ability of a chronic administration of KN-93 (5 mg kg−1alt diem for 4 weeks), an inhibitor of CaMKII, to modulate the altered vasoreactivity of the perfused mesenteric bed to common vasoconstrictors and vasodilators in streptozotocin (STZ)-induced diabetes. 3 The vasoconstrictor responses induced by noradrenaline (NE), endothelin-1 (ET-1), and angiotensin II (Ang II), were significantly increased whereas, vasodilator responses to carbachol and histamine were significantly reduced in the perfused mesenteric bed of the STZ-diabetic rats as compared with non-diabetic controls. 4 Inhibition of CaMKII by KN-93 treatment did not affect blood glucose levels but produced a significant normalization of the altered agonist-induced vasoconstrictor and vasodilator responses. KN-93 did not affect agonist-induced responses in control animals. In addition, KN-93 significantly reduced weight loss in diabetic rats. 5 The present data suggest that CaMKII is an essential mediator in the development of diabetic vascular dysfunction and may also play an important role in signalling pathways leading to weight loss during diabetes.

Notizen: 1 In the present investigation we examined the regulation of calmodulin (CaM)- and protein kinase C (PKC)-dependent pathways by cytosolic Ca2+ in the contraction of cat lower oesophageal sphincter (LES). 2 Force developed in response to increasing doses of acetylcholine (ACh) was directly related to the increase of the [Ca2+]i measured by fura-2. Thapsigargin, which depletes Ca2+ stores, reduced the contraction and the [Ca2+]i. In addition, contraction in response to maximal ACh was reduced by the CaM inhibitor CGS9343B but not by the PKC inhibitor chelerythrine. The contraction in response to submaximal ACh was reduced by chelerythrine but not by CGS9343B. 3 In permeabilized cells, the contraction in response to low Ca2+ (0.54 μm) was also reduced by CGS9343B. 4 The response to high Ca2+ (1.0 μm) was reduced by CGS9343B. ACh also inhibited PKC activation induced by diacylglycerol, which activation is inhibited by the N-myristoylated peptide inhibitor derived from pseudosubstrate sequences of PKCαβγ (myr-PKC-αβγ), but not of myr-PKC-α. 5 These data are consistent with the view that activated CaM-dependent pathways inhibit PKC-dependent pathways, this switch mechanism might be regulated by Ca2+ in the LES.

Notizen: 1 Approximately 45% of patients with diabetes mellitus have gastrointestinal complications such as diarrhoea and constipation, but the underlying aetiology is unclear. The present study investigates alterations in spontaneous motility of the colon that may be, in part, responsible for these symptoms using an established animal model of diabetes.2 Rats were rendered diabetic by a single intraperitoneal injection of streptozotocin and age-matched controls were injected with citrate buffer. Rats were sacrificed after 8-weeks and proximal colonic circular muscle tissue mounted in organ baths.3 Spontaneous activity was observed in both control and diabetic tissues, but this activity was almost doubled in colonic tissue taken from diabetic rats. It was hypothesized that this increase was due to a deficit in inhibitory control of the colon in the diabetic state.4 Possible alterations in nitrergic and vasoactive intestinal polypeptide (VIP)ergic control were investigated using a range of pharmacological tools.5 Sodium nitroprusside, VIP and antioxidants (reduced glutathione, ascorbate and α-tocopherol) inhibited the spontaneous activity, but the level of inhibition observed was not different in diabetic tissue compared with control.6 Arginine, [d-p-Cl-Phe6, Leu17]-VIP and α-chymotrypsin had no effect on spontaneous activity in either sets of tissue.7 N-nitro-l-arginine produced a small, but significant, increase in the level of spontaneous activity, but the degree of increase was not different between control and diabetic tissues.8 Western blots demonstrated that there was no inducible-nitric oxide synthase (iNOS) in control or diabetic tissues and that the levels of endothelial-NOS (eNOS) and neuronal-NOS (nNOS) detected were not statistically significantly different. The [3H]-citrulline assay established that the functionality of the NOS isoforms present were unaltered in the diabetic state.9 This study demonstrates that there is a marked alteration in motility in the colon taken from diabetic animals. However, the change in motility is unlikely to be due to a change in inhibitory control mechanisms and may be due to an increased excitability.

Notizen: 1 Pig nasal mucosal strips were incubated with α-adrenoceptor antagonists followed by α2-adrenoceptor agonist concentration–response curves. 2 Contractions elicited by the α2-adrenoceptor agonists BHT-920 (pD2 = 6.16 ± 0.07), UK 14,304 (pD2 = 6.89 ± 0.13) and PGE-6201204 (pD2 = 7.12 ± 0.21) were blocked by the α2-adrenoceptor antagonist yohimbine (0.1 μm). In contrast, the α1-adrenoceptor antagonist prazosin (0.03 μm) had no effect on the BHT-920-, UK 14,304- and PGE-6201204-induced contractions, but blocked the contractile response to the α1-adrenoceptor agonist phenylephrine (pD2 = 5.38 ± 0.04) and the mixed α1- and α2-adrenoceptor agonist oxymetazoline (pD2 = 6.30 ± 0.22). 3 The α2-adrenoceptor antagonist yohimbine (0.01–0.1 μm, pA2 = 8.04), α2B/C-adrenoceptor antagonist ARC 239 (10 μm, pKb = 6.33 ± 0.21), α2A/C-adrenoceptor antagonist WB 4101 (0.3 μm, pKb = 8.01 ± 0.24), α2A-adrenoceptor antagonists BRL44408 (0.1 μm, pKb = 6.82 ± 0.34) and RX 821002 (0.1 μm, pKb = 8.31 ± 0.35), α2C-adrenoceptor antagonists spiroxatrine (1 μm, pKb = 7.32 ± 0.32), rauwolscine (0.1 μm, pKb = 8.16 ± 0.14) and HV 723 (0.3 μm, pKb = 7.68 ± 0.14) inhibited BHT-920-induced contractions in pig nasal mucosa. 4 The present antagonist potencies showed correlations with binding affinity estimates (pKi) obtained for these antagonists at the human recombinant α2A- and α2C-adrenoceptors (r = 0.78 and 0.83, respectively) and with binding affinity estimates (pKd) obtained in pig native α2A- and α2C-monoreceptor assays (r = 0.85 and 0.78, respectively). No correlation was observed for the α2B-subtype. 5 In conclusion, contractile responses to phenylephrine, BHT-920, UK 14,304, PGE-6201204 and oxymetazoline indicate that α1- and α2-adrenoceptors are present and mediate vasoconstriction in pig nasal mucosa. Furthermore, correlation analysis comparing antagonist potency in pig nasal mucosa with affinities for human recombinant α2-adrenoceptors and native pig α2-adrenoceptors suggest that α2A- and α2C-adrenoceptor subtypes constrict pig nasal mucosa vasculature.

Notizen: 1 The relationship between the effects of endogenous nitric oxide (NO) and prostanoids on the noradrenaline (NA)-induced contractions and the mechanisms involved were investigated in the rat perfused mesenteric bed, using NG-nitro-l-arginine methyl ester (l-NAME), a NO synthase inhibitor and sodium nitroprusside (SNP), a NO donor.2 The constrictor responses to NA were reduced to 50% by the cyclooxygenase inhibitor 10 μm indomethacin as well as by 1 μm SNP. When indomethacin and SNP were perfused simultaneously the contractions were further reduced.3 The NA-induced contractions were increased by the addition of 400 μml-NAME and the addition of either indomethacin or SNP abolished such increases. The simultaneous perfusion of both agents further reduced the contractions.4 Removal of the endothelium increased NA-induced contractions to a similar extent as l-NAME and this increase was abolished by indomethacin as well as by SNP.5 The perfusion of 10 μm NA augmented the release of prostaglandin (PG) F2α by the mesenteric bed without modifications in any other prostanoid. In the presence of l-NAME, this effect was further increased. However, SNP abolished the NA-induced stimulation of PGF2α release.6 In de-endothelialized preparations NA also stimulated PGF2α production as observed in intact preparations. This effect was more marked in the presence of l-NAME; in contrast, SNP abolished the stimulation.7 In conclusion, the present results suggest an opposite action between NO and PGF2α on the NA-induced contractions in the rat mesenteric bed.

Notizen: 1 The present study was carried out to characterize the effect of adenosine on calcium dynamics in the rat portal vein. Isolated portal vein of male albino rats was used as the experimental model as it exhibits autorhythmicity. Adenosine and its analogues 2-CAD, N6-CHA and NECA were used to characterize the type of adenosine receptor involved and 2-CAD was used along with adenosine throughout the other part of study to characterize the effect of adenosine on Ca2+ dynamics.2 Adenosine and its analogues were found to inhibit the spontaneous contractions of rat portal vein in a concentration-related manner. The order of potency was NECA 〉 2-CAD 〉 N6-CHA 〉 adenosine. Incubation of the tissue with CGS∼15943A, an adenosine receptor antagonist, had a per se enhancing effect on autorhythmicity. Adenosine and 2-CAD failed to reverse the contractile response produced by hypertonic KCl (80 or 30 mm). Whereas adenosine and 2-CAD effectively relaxed the tissues contracted with phenylephrine (10−5 m).3 Preincubation of the tissue with 2-CAD (10−4, 10−5 or 10−6 m) for 5 min raised the threshold concentration of CaCl2 to evoke contractile response and also significantly increased the mean EC50 values of CaCl2. Nifedipine was found to be more potent than 2-CAD on Ca2+ channels.4 The results of the present study suggest that the endogenous adenosine plays a significant role in producing vascular relaxation through the participation of A2 receptor subtype. This effect may be due to its inhibitory effect on release of Ca2+ from the intracellular stores. Further to this effect, 2-CAD had a major inhibitory effect on voltage-operated Ca2+ channels compared with receptor-operated Ca2+ channels.5 It can be concluded that adenosine through its A2 receptor produces vasorelaxant effect by interfering with the release of Ca2+ from the intracellular stores coupled with influx of Ca2+ from the extracellular sources.

Notizen: 1 The prolonged infusion of 1,3-dipropyl-8-sulfophenylxanthine (DPSPX), a non-selective antagonist of adenosine receptors, induces hypertension, an increase in plasma renin activity and morphological cardiovascular changes. 2 The aim of this work was to evaluate the effects of losartan, a selective AT1 receptor antagonist, and atenolol, a β-adrenoceptor antagonist, on DPSPX-induced hypertension. 3 Male Wistar rats (250–300 g, n = 4–6) were treated for 1 or 4 weeks with: saline i.p.; DPSPX (90 μg kg−1 h−1) i.p.; losartan (15 mg kg−1 day−1) p.o.; atenolol (25 mg kg−1 day−1) p.o.; DPSPX (90 μg kg−1 h−1) i.p. + losartan (15 mg kg−1 day−1) p.o.; DPSPX (90 μg kg−1 h−1) i.p. + atenolol (25 mg kg−1 day−1) p.o. Blood pressure was measured by the ‘tail-cuff’ method in conscious animals. Fragments of the mesenteric and tail arteries were processed for morphological study and the mean diameter of the vascular smooth muscle cells was determined. 4 DPSPX increased blood pressure. Losartan and atenolol prevented this rise but had no effect on blood pressure of control rats. DPSPX-treated groups showed hypertrophy of the vascular smooth muscle cells and proliferation of subintimal cells. Losartan but not atenolol prevented these changes. Losartan had no effect on the vascular morphology of control rats, while treatment with atenolol for 4 weeks induced hypertrophy of the vascular smooth muscle cells. 5 Both losartan and atenolol counteract the development of DPSPX-induced hypertension but only losartan prevents the alterations in vascular morphology.

Notizen: 1 The characteristics of semicarbazide-sensitive amine oxidase (SSAO) are reviewed and the unknown physiological or pathological role of this enzyme emphasized. 2 The various mechanisms of action proposed for the vasodilator drug hydralazine are considered. In particular, the inhibitory action on various enzymes, related or not to cardiovascular function, are discussed. 3 Studies linking inhibition of SSAO to hydralazine hypotension are reviewed and a general hypothesis relating both actions is presented. The hypothesis postulates that (a) vascular SSAO is involved in the regulation of vascular tone, and (b) hydralazine vasodilation is the consequence of vascular SSAO inhibition. 4 Evidence supporting these postulates is presented and vascular SSAO inhibition is proposed as a novel mechanism of vasodilation.

Notizen: 1 The regulation by angiotensin II (Ang II) formed locally on nerve-stimulated purinergic and adrenergic components of double-peaked vasoconstrictions in the canine splenic artery and Ang II receptor subtypes involved were investigated. 2 The perfusion of the precursor angiotensin I (Ang I, 0.1–1 nm) did not affect the vasoconstrictor responses to noradrenaline (NA, 0.03–1 nmol) and adenosine 5′-triphosphate (ATP, 0.03–1 μmol). The second component vasoconstrictor response to nerve stimulation was dose dependently potentiated by Ang I (0.1–1 nm). The first peaked constriction was slightly, but insignificantly increased. The potentiating effects of Ang I were abolished by KRH-594 (10 nm), a selective AT1 receptor antagonist, but not by PD 123319 (1–10 nm), an AT2 receptor antagonist. KRH-594 (10 nm) or PD 123319 (10 nm) never affected the vasoconstrictions to either NA or ATP. 3 The treatment with KRH-594 (1–10 nm) produced a greater inhibition on the second peaked response than the first one, although both of them were dose dependently inhibited. PD 123319 (1–10 nm) did not affect the vasoconstrictor responses induced by nerve stimulation. 4 Inhibition of angiotensin-converting enzyme with 10 nm enalaprilat reduced the second peaked response, having no significant inhibition on the first peaked response. A higher dose of enalaprilat (100 nm) produced a greater inhibition of the second peak than the first one. It reduced the second peak by approximately 65%, while the first peak was decreased approximately 35%. After treatment with enalaprilat, Ang I (1 nm) failed to enhance the neuronal vascular response. Enalaprilat at doses used did not affect the vasoconstrictions to either NA or ATP. 5 The present results indicate that endogenously generated Ang II may produce a more marked potentiation of adrenergic transmission than purinergic transmission via activation of prejunctional AT1 receptors.

Notizen: 1 The aim of this study was to investigate the co-localization of histamine and dopamine-β-hydroxylase in the superior cervical ganglion of guinea-pig and release of histamine from cardiac sympathetic terminals in guinea-pig isolated atrium. 2 Histidine decarboxylase (a histamine-synthesizing enzyme) mRNA signals were detected in the neurones of superior cervical ganglion of guinea-pig by in situ hybridization. The results of double-labelled immunofluorescence further confirmed the co-localization of histamine and dopamine-β-hydroxylase in the large principle neurons and small intensely fluorescent cells in the superior cervical ganglion. The immunoreactivities of both histamine and dopamine-β-hydroxylase were significantly attenuated after 6-hydroxydopamine-induced lesion of sympathetic nerves. 3 The refractory electrical field stimulation caused the release of histamine from cardiac sympathetic terminals of guinea-pig isolated atria (112.14 ± 40.34 ng ml−1), which was significantly attenuated to 35 ± 15.57 ng ml−1 by reserpine pretreatment. Following administering compound 48/80, a mast cell degranulator, electrical field stimulation induced a dramatic increase of endogenous histamine release from isolated atria (303.57 ±72.93 ng ml−1). When compound 48/80 was added to the reserpine-treated atria, the release of histamine induced by field stimulation was decreased to 207.14 ± 76.39 ng ml−1. 4 These results provide novel evidence that histamine co-exists with noradrenaline in sympathetic nerves and might act as a neurotransmitter to modulate sympathetic neurotransmission.

Notizen: 1 The aim of the current study was to investigate in HT-29 human colon cancer cell line, the existence of functional receptors for the signalling molecules, noradrenaline (NA), prostaglandin E2 (PGE2), and adenosine-5′-triphosphate (ATP).2 We utilized microphysiometry, which monitors on-line extracellular acidification rate (ECAR) as a measure of cellular metabolic activity, and how this variable is altered by signalling molecules.3 Challenge with NA (5.9 μm) resulted in an increase in ECAR by approximately 24% of basal.4 PGE2 (0.0284, 0.284 and 2.84 μm) hardly affected ECAR.5 ATP (100 μm) elicited a biphasic effect on ECAR (increase and decrease in ECAR by about 58 and 10% of basal, respectively).6 HT-29 cells were shown to express COX-2 by immunocytochemistry.7 These data suggest the presence of functional receptors for NA and ATP, but not for PGE2 in HT-29 human colon cancer cell line.

Notizen: 1 Cardiac vagal outflow is the major factor determining the magnitude of heart rate (HR) variability analysed by traditional time and frequency domain methods. New analysis techniques, such as fractal and complexity methods, have been developed to probe non-linear features in HR behaviour that may not be detectable by traditional methods.2 We investigated the effects of vagal blockade (glycopyrrolate i.v. 5 μg kg−1 h−1 for 2 h, n = 8 vs. unmedicated control group, n = 8) and various breathing patterns (n = 12) on two non-linear measures of HR variability – detrended fluctuation analysis (DFA) and approximate entropy (ApEn) – in healthy male volunteers.3 Glycopyrrolate decreased the mean (±SD) ApEn from 1.46 ± 0.18 to 0.85 ± 0.24 (P = 0.001 in comparison with the control group), and increased the short-term (α1) and intermediate-term (α2) fractal scaling exponents of DFA, α1 from 0.96 ± 0.19 to 1.43 ± 0.29 (P = 0.003) and α2 from 1.13 ± 0.10 to 1.34 ± 0.14 (P 〈 0.001).4 Decrease in fixed respiration rate from 15 to 6 breaths min−1 increased α1 from 0.83 ± 0.25 to 1.18 ± 0.27 (P 〈 0.001), but decreased α2 from 0.88 ± 0.09 to 0.45 ± 0.17 (P 〈 0.001) and ApEn from 1.26 ± 0.12 to 1.10 ± 0.14 (P = 0.028). Rapid breathing (24 min−1) had no influence on these non-linear measures of HR variability. Hyperventilation (15 min−1, tidal volume increased voluntarily by 0.5 l) decreased α1 from 0.83 ± 0.25 to 0.66 ± 0.28 (P = 0.002) but did not affect α2 or ApEn.5 To conclude, vagal blockade alters the fractal scaling properties of R-R intervals (α1, α2) and reduces the complexity (ApEn) of HR behaviour. Both the fractal and complexity measures of HR variability can also be influenced by changes in the breathing pattern.

Notizen: 1 Inflammatory bowel disease (IBD) is a condition that involves proinflammatory cytokines such as interleukins 1β and 6 (ILs). In this disease, it has been shown that an abnormal microcirculatory system is implicated. 2 Therefore, the effects of in vivo treatment for three days with interleukins 1β and 6 were investigated on rat isolated mesenteric vascular bed (MVB). 3 A significant concentration-dependent increase in vascular response to noradrenaline (NA) was found, with a significant difference in Emax between control (93.01 ± 16.78 mmHg) and treated preparations (137.91 ± 5.20 mmHg). Endothelin-1(ET-1) induced a significantly greater increase of perfusion pressure in treated rats in comparison with control rats at the highest concentration used (0.1 μm). 4 The concentration-dependent decrease of perfusion pressure induced by acetylcholine (ACh) in MVB precontracted with NA was significantly reduced in specimens from treated rats in comparison with control rats, with a significant difference in Emax between control and treated preparations. 5 Perivascular nerve stimulation (PNS) evoked contractions with no difference between treatments. Similarly, no difference in relaxant effect was found after PNS in specimens precontracted with NA, in the presence of guanethidine. 6 These findings indicate that the precocious inflammation acts only at postsynaptic level, facilitating vascular contraction. These data seem to support the hypothesis that vascular dysfunction caused by overproduction of ILs may contribute, among other immunological factors, to vasculitis in IBD that leads to intestinal ischaemia through vasoconstriction.

Notizen: 1 The present study was designed to analyse the possible involvement of V1- and V2-receptors in vasopressin (AVP)-induced facilitation of the sympathetic nervous system. Furthermore, we aimed to determine whether the site of facilitation by AVP is located pre- or postsynaptically. 2 Electrical field stimulation (EFS) was applied on the rat mesteric artery to activate the sympathetic nervous system. In addition, we evaluated the direct vascular effects of AVP. The postsynaptic effect of AVP on the sympathetic nervous system was investigated by exposing the vessels to exogenous noradrenaline. These experiments were performed in the absence or presence of selective V1 and V2 receptor antagonists SR 49059 and SR 121463, respectively. Desmopressin was applied as a selective V2 agonist. 3 The direct vasoconstrictor effect of AVP was antagonized by SR 49059 and not by SR 121463. Desmopressin neither showed any direct vasoconstrictor effect nor produced vasodilatation after a precontraction induced by noradrenaline (10 μm). The EFS-induced rise in vascular tone could be increased by a sub-pressor concentration of AVP. This fascilitation could be antagonized by SR 49059, but not by SR 121463. Desmopressin did not influence the increase in vascular tone during EFS. Vasoconstriction induced by exogenous noradrenaline could be facilitated by a sub-pressor concentration of AVP and this selective postsynaptic effect could be antagonized by V1-receptor blockade. 4 In conclusion, the AVP-induced facilitation of the sympathetic nervous system is completely V1-receptor dependent and at least partly postsynaptically mediated.

Notizen: 〈list xml:id="l1" style="custom"〉1To validate the relationship between the dopaminergic, opioidergic and cholinergic nervous systems, we evaluated the effect of domperidone, a dopamine (D2) antagonist, on the opioid system in myenteric plexus-longitudinal muscle preparation isolated from the guinea-pig ileum.2One micromolar of domperidone did not affect the 0.1 Hz-evoked (duration 0.5 ms, maximum intensity) twitch response, but concentration dependently inhibited the twitch response between concentrations of 2 and 20 μm, and the inhibition was maximum after 20–30 min at the highest concentration used (20 μm).3 Acetylcholine-evoked contraction on basal tension was also not inhibited by 1 μm domperidone, but the contraction was concentration dependently inhibited at concentrations of 10–100 μm in a non-competitive manner.4One micromolar of domperidone, however, increased post-tetanic twitch inhibition, an indicator of the release of endogenous opioids. This increase was completely antagonized by 1 μm naloxone.5Twitch inhibition induced by dynorphin 1–13 (0.1–10 nm) was not affected by 1 μm domperidone, but increased the maximum twitch inhibition caused by morphine (0.1–1 μm).6These results might reflect the existence of an interaction between the dopaminergic and opioidergic system without the inhibition of the cholinergic system. Dopamine antagonists increased opioid action, an action that may depend more on the increased release of endogenous opioids than on supersensitivity of the opioid receptor.

Notizen: 1 The present study compared the effect of the administration of tachykinin NK1- and NK2-receptor antagonists alone and in combination on exogenous and endogenous tachykinin-induced contractions using three different guinea-pig airway preparations: isolated bronchus, isolated perfused lung and in vivo. 2 In the isolated bronchi, the tachykinin NK1-receptor antagonist CP 99994 (0.01–1 μm)produced concentration-dependent inhibition of contractions induced the tachykinin NK1-receptor agonists substance P (SP) and [Met-OMe11] SP ([Met-OMe11]SP), whereas the tachykinin NK2-receptor antagonist SR 48968 (0.1 μm) had no effect. SR 48968 (0.001–0.01 μm)concentration-dependently inhibited contractions induced by the tachykinin NK2-receptor agonists neurokinin A (NKA) and [β-Ala8]-neurokinin A (4–10) ([βAla8]-NKA) whereas CP 99994 (0.1 μm) did not inhibit the contractions. The contractile activity of capsaicin, an agent that releases endogenous tachykinins from sensory C-fibres, was inhibited in a concentration dependent manner by SR 48968 (0.001–0.03 μm) but not by CP 99994 (0.1 μm). Combination of CP 99994 and SR 48968 caused increased inhibitory effects on the concentration–response curves to SP, [Met-OMe11]SP, NKA, [β-Ala8]-NKA and capsaicin. 3 In isolated perfused lungs, SR 48968 concentration (0.01–10 μm) dependently inhibited NKA-, [β-Ala8]-NKA- and capsaicin-induced bronchoconstriction whereas CP 99994 (30 μm) had no effect on SP-, NKA-, [β-Ala8]-NKA- and capsaicin-induced bronchoconstriction. Combination of inactive concentrations of CP 99994 and SR 48968 produced an increased inhibitory effect on all previous stimuli-induced bronchoconstriction. 4 In in vivo guinea-pig studies, intravenous and oral pretreatment with SR 48968 (0.01–1 mg kg−1 i.v. and 0.1–3 mg kg−1 p.o., respectively), but not with CP 99994 (1 mg kg−1 i.v. and 0.3–30 mg kg−1 p.o., respectively), produced a dose-dependent inhibition of the bronchoconstrictor responses induced by NKA, [β-Ala8]-NKA and capsaicin. CP 99994 intravenously (0.3 mg kg−1) and orally (3–10 mg kg−1) inhibited SP-induced bronchoconstriction only. Intravenous and oral low dose combinations of CP 99994 and SR 48968 produced an increased inhibition of SP-, NKA-, [β-Ala8]-NKA- and capsaicin-induced bronchoconstriction, respectively. 5 The present data indicate that combined tachykinin NK1- and NK2-receptor antagonist treatment compared with single antagonist treatment, using CP 99994 and SR 48968, produced an augmented blockade of tachykinin NK1-, NK2- and capsaicin-mediated contractions in guinea pig airways. These findings support the hypothesis that a dual NK1- and NK2-receptor antagonist may provide an advantage over single activity tachykinin NK1- or NK2-receptor antagonists in pulmonary obstructive diseases.

Notizen: 1 One reason why rabbit jejunum is suitable for studying the mechanisms underlying the actions of the various neurotransmitters and their interactions is its spontaneous motility. The main regulator of spontaneous motility is the cholinergic system. How the cholinergic system regulates the spontaneous activity in the rabbit jejunum and how it affects the inhibitory action of α- and β-adrenoceptor agonists remains unclear. 2 We studied the influence of the cholinergic system and apamin-sensitive Ca2+-activated K+ channels on spontaneous contractions in the rabbit jejunum and on the inhibitory effects ofα1- and β-adrenoceptor agonists. 3 In naïve tissues, atropine (ATR, 7.4 × 10−8 m) and tetrodotoxin (8 × 10−8 m) almost completely inhibited – to a similar extent – the amplitude of spontaneous activity. Despite the presence of ATR or TDX, tissue contraction gradually recovered to about 50% of the baseline amplitude within 5–10 min. When ATR or TDX, respectively, were added to the TDX- or ATR-treated tissues, the recovered activity decreased weakly but significantly. After washout and a 45-min rest the contraction amplitude returned to baseline values. A further exposure to ATR or TDX reduced the contraction to a level significantly lower than the one obtained after TDX or ATR added 5 min after ATR or TDX, respectively. In preparations prestimulated for 10 min with acetylcholine (ACh), ATR abolished the TDX-resistant recovered spontaneous activity. 4 Adrenaline (ADR, 0.5–5 × 10−7 m) and phenylephrine (PHE, 1–10 × 10−7 m) inhibited tissue motility in naïve and in ATR- and in TDX-exposed preparations. But whereas in naïve preparations the α1-adrenoceptor antagonists completely antagonized inhibition induced by both drugs, in ATR- and TDX-exposed tissues they did so only partially for ADR. Agonist-induced inhibition had a rapid onset but rapidly faded; pendular movements took significantly longer to recover in ATR- and TDX-treated tissues than in naïve tissues. In tissues exposed for 2 min to ADR (0.5–5 × 10−7 m) or PHE (1–10 × 10−7 m), washout or addition of α1-adrenoceptor antagonists caused an immediate short-lasting increase in contraction amplitude. 5 Apamin (APAM, 5 × 10−9 m) caused a rapid and persistent increase in the amplitude of contractions. It also blocked the inhibitory responses to ADR and PHE, and removed washout-induced contractions. The APAM-induced increase in the contraction amplitude correlated with the increase obtained by washing out ADR or PHE. 6 Isoprenaline (at concentrations up to 2.8 × 10−7 m) produced no inhibitory response in naïve tissues, but it invariably blocked (at a concentration of 0.7 × 10−7 m) the recovered spontaneous activity (and sometimes depressed muscletone) in tissues exposed to ATR or TDX. Neither propranolol (3.4 × 10−7 m) nor APAM (5 × 10−9 m) counteracted these inhibitory effects. 7 These results indicate that spontaneous motility in the rabbit jejunum is predominantly mediated by neuronal release of ACh and by some other unidentified neuronal activity. Released ACh inhibits myogenic activity and strongly antagonizes β-adrenoceptor-induced APAM-insensitive inhibition but leaves α1 agonist-induced APAM-sensitive inhibition unchanged.

Notizen: 1 This study used contractility methods with the portal veins of 5- and 14-week-old Wistar–Kyoto normotensive rats (WKY) and spontaneously hypertensive rats (SHRs). The SHRs are prehypertensive at 5 weeks. 2 The first part of our study was to determine whether the responsiveness to isoprenaline and forskolin was altered in the maturation of portal veins from normo- and prehypertensive rats. The responses to forskolin were similar on the portal veins of 5- and 14-week-old WKY and SHRs. 3 The sensitivity and maximum responses to isoprenaline were similar on portal veins of 5- and 14-week-old WKY. The sensitivity and maximum responses to isoprenaline were lower on the portal veins of 5-week-old SHRs (pD2 = 8.25, maximum = 85%) than age-matched WKY (pD2 = 8.79, maximum = 96%); these differences are not caused by hypertension. At 14 weeks, the sensitivity was similar (WKY pD2 = 8.74, SHR pD2 = 8.65) but the maximum responses to isoprenaline were lower on the portal veins SHRs (77%) than WKY (97%). Thus, the sensitivity to isoprenaline increases with the development of hypertension in the SHR portal vein. 4 The second part of the study was to determine whether the affinity for isoprenaline at β2-adrenoceptors and the fractional β2-adrenoceptor occupancy–response relationships on the portal vein were altered in maturation from normo- and pre-hypertensive rats. The effects of bromoacetylalprenololmenthane (BAAM), an irreversible β-adrenoceptor blocker, on the isoprenaline responses of 5- and 14-week-old WKY and SHRs were studied. Maturation of the WKY portal vein between 5 and 14 weeks was associated with a loss of affinity for isoprenaline (from pKA of 7.13 to 7.87), and increase in β2-adrenoceptor reserve (from 72 to 92% at the 95% response). There were similar affinity and reserve findings in the maturation of the SHR portal vein. Thus, there are major changes in β2-adrenoceptor structure and reserve in maturation on the portal vein that are irrespective of the development of hypertension.

Notizen: 1 It is generally recognized that the vasodilator hydralazine produces hypotension accompanied by baroreflex-mediated tachycardia. In some experimental conditions, however, the accompanying heart rate change is bradycardia, a paradoxical response which has not been satisfactorily explained. The present study examined the possibility of hydralazine-induced bradycardia being mediated by vagal or sympathetic afferents activated by changes in left ventricular pressure. 2 Systolic blood pressure and heart rate responses to hydralazine were recorded in conscious normotensive intact rats by a tail cuff method and compared with responses in animals subjected to previous sino-aortic deafferentation (SAD) to remove the influence of the arterial baroreflex. Responses were also obtained after blockade of myocardial afferent vagal C-fibres with urethane, of efferent vagal impulses to the heart with methylatropine, of positive inotropic effects of hydralazine with atenolol, and of prostanoid sensitization of myocardial nerve fibres with indomethacin. 3 Hydralazine produced hypotension and tachycardia in intact rats, and hypotension and bradycardia in SAD animals. In intact rats, this pattern was not affected by any of the pretreatments, while in SAD rats, all pretreatments reversed the bradycardia to hydralazine. 4 The present results indicate that suppression of the arterial baroreflex by SAD propitiates the appearance of a bradycardiac response to hydralazine. This reaction probably results from activation of a vagal cardiodepressant reflex originating in the heart, as suggested by its blockade by drugs acting at various sites along the reflex arch.

Notizen: 1 In the present study, we investigated the effect of chronic ethanol administration on nitric oxide (NO)-mediated responses in rat isolated trachea preparation. 2 Ethanol was given to rats in a modified liquid diet for 21 days. Isolated tracheal rings were then used to obtain responses to electrical field stimulation (EFS) after precontraction with 100 μm histamine. The parameters of field stimulation were as follows: supramaximal voltage of 50 V, 0.5 ms duration, 10-s train; 0.5, 1, 3, 5, 10, 20, 30 and 50 Hz at 2-min intervals. The effects of l-and d-arginine (10−6 m) on the responses to field stimulation (10–20 Hz) were studied. In other experiments, we tested the effects of Nω-nitro-l-arginine methyl ester (l-NAME, 10−6–10−5 m) and SIN-1 (10−6–10−5 m) on the responses to field stimulation. 3 Electrical field stimulation induced relaxation responses in the tracheal rings precontracted with histamine from control- and ethanol-treated rats. The relaxation responses induced by EFS were significantly reduced in the tracheal rings precontracted with histamine from ethanol dependent group. The responses induced by EFS in both groups were completely abolished by tetrodotoxin (1 μm), but unaffected by hexamethonium (1 μm). Incubation with d-arginine did not cause statistically significant increases in relaxation responses to EFS in both groups. l-Arginine (10−6 m) caused statistically significant increases in relaxation responses to EFS in control rats, but not in ethanol dependent rats. Incubation with l-NAME (10−6–10−5 m) caused statistically significant inhibition of the relaxation responses to EFS in both groups. SIN-1 (10−6–10−5 m) induced significantly increase in relaxation responses to EFS in both groups. 4 Our results suggest that the possible mechanism responsible for inhibition of tracheal inhibitory responses to EFS in ethanol-dependent rats may be a reduction in production of NO and in the uptake of l-arginine.

Notizen: Abstract The use of the Internet and World Wide Web (WWW) as a distributive medium is seen by many businesses as a legitimate way to cut costs of operation. Confidence is growing in the use of this medium to transact business because of the increasing sophistication of firewalls, encryption software, and digital key technology. This paper presents empirical evidence from one offshore financial center where the process of legislative and regulatory reform put in place to establish confidence in the traditional provision of offshore financial services is now being used to regulate and legitimize the online distribution of such services. The results show that all firms surveyed for this study use the Internet for routine brochure-ware purposes and the larger firms (particularly in the offshore life insurance sector) are developing more sophisticated customized transactional functions via extranet platforms. Tensions exist though with respect to “regulatory grasp” via the Internet, as offshore places are being put under increased pressure by supranational organizations such as the Organization for Economic Cooperation and Development (OECD) and Financial Action Task Force (FATF) to require greater transparency in offshore financial transactions.

Notizen: Utilizing data from the 1980 and 1990 U.S. census, this study investigates whether the passage of official-English legislation at the state level during the 1980s affected the housing acquisition of foreign-born Hispanics. The results suggest that both limited-English-proficient (LEP) and English-fluent Hispanic immigrants who resided in states that passed English-only legislation were less likely to acquire a home during the 1980s compared to their counterparts in other areas. Consistent with economic theory, however, the group that seemed to be most affected included older LEP residents. One explanation for these findings is that the official-English legislation mirrored growing xenophobia against foreign-born Hispanics, resulting in additional social stratification on the basis of ethnicity in housing markets.

Notizen: This paper attempts to reflect critically on the role which telephone call centers might play in the economic development of rural places in the ‘information age’, drawing mainly on a case study of the Highlands and Islands of Scotland. It argues that although call center employment tends mainly to be urban-based, the growth of this form of work does present opportunities for some rural areas. The paper considers the locational factors rural areas would have to possess or develop in order to attract such work. It suggests call centers can make a valuable, though limited, contribution towards rural economic development, principally through the creation of additional employment opportunities and the stimulation of new skills and competencies. It also suggests that call centers do not represent a panacea for rural areas and that, indeed, it would be dangerous for rural areas to become over-reliant on employment in this sector.

Notizen: The capabilities of central office (CO) telephone switches in four southeastern states (Kentucky, Mississippi, North Carolina, and Tennessee) provide detail on spatial variation in telecommunications technologies. A proposed six-level hierarchy of switch capability was used. Switches with digital capability are concentrated disproportionately in metropolitan areas, largely in response to larger numbers of business establishments. The overall picture in the Southeast is one of tremendous variation—variation across states and variation within the four states being studied. Rural (nonmetro) counties generally, but not always, have both fewer switches overall and fewer switches with digital capability. North Carolina and Tennessee, the two most urban of the four states, also have seen the greatest entry by new telecommunications competitors. These two states have the largest percentages of advanced (digital) switches in both metro and rural counties. At the county level, the number of switches is primarily a function of a county's population but, even more significantly in three states, of the number of business establishments in the county. On the whole, it is residents of metropolitan—not rural—areas who are most likely to be served by newer forms of digital telecommunications.

Notizen: The e-economy is part of a larger phenomenon, technocapitalism, that is transforming business organizations and the ways in which they transact, produce, and ship their goods. Technocapitalism is an evolution of market capitalism that is rooted in technological innovation and supported by such intangibles as creativity and knowledge. This paper considers first the main characteristics of networks that support the e-economy and its source phenomenon, the emergence of technocapitalism. Networks are thought to be the main vehicle through which the e-economy spreads, and they have major effects on the organization of business firms. The culture of technocapitalism, with its emphasis on continuous innovation and rapid adjustment, is largely behind the rising importance of networks. A second section then considers the deconstruction of business firms and its relation to networks, the e-economy, and the rise of technocapitalism. A historical perspective is provided to show the contrast with previous eras. The deconstruction of business organizations involves a major transformation of the norms and ways in which firms are run and structured. Finally, the likely implications for transportation and shipping of the rise of the e-economy, its networks, and the deconstruction of firms are discussed. The logistics, pricing, and infrastructure of shipping are likely to be substantially affected by the spread of the e-economy, its networks, and the deconstruction of firms.

Notizen: This paper presents a critical survey of some recent developments in the theory of international trade. Particular emphasis is given to the role of increasing returns to scale and labor mobility in shaping the pattern of industrial location across integrating countries. The goal is to review and discuss the novel insights and predictions of the so-called “new” theories in order to pose and stimulate avenues for future research.

Notizen: Land-use and -cover change is a topic of increasing concern as interest in forest and agricultural land preservation grows. Urban and residential land use is quickly replacing extractive land use in southern Indiana. The interaction between land quality and urban growth pressures is also causing secondary forest growth and forest clearing to occur jointly in a complex spatial pattern. It is argued that similar processes fuel the abandonment of agricultural land leading to private forest regrowth, changes in topography and land quality, and declining real farm product prices. However, the impact of urban growth and development on forests depends more strongly on changes in both the residential housing and labor markets. Using location quotient analysis of aggregate employment patterns, and the relationship between regional labor market changes, the extent of private forest cover was examined from 1967 to 1998. Then an econometric model of land-use shares in forty southern Indiana counties was developed based on the net benefits to agriculture, forestland, and urban uses. To test the need to control explicitly for changes in residential demand and regional economic structure, a series of nested models was estimated. Some evidence was found that changing agricultural profitability is leading to private forest regrowth. It was also uncovered that the ratio of urban to forest land uses is better explained by incorporating measures of residential land value and industrial concentration than simply considering population density alone.

Notizen: Abstract This paper analyzes the productivity growth of the Spanish regions between 1965 and 1995, decomposing productivity gains into technological progress and efficiency change by means of Malmquist indices. Once estimates of efficiency are obtained, the aim of this paper is to analyze the effects of human and public capital on growth in terms of their impact on Total Factor Productivity (TFP). Public capital is believed to increase the productivity of the private factors of production whereas human capital is thought to contribute to the production process as an additional input and to have a dynamic influence on growth through its impact on technological innovation (shifts in the production frontier) and technological diffusion (movements toward the frontier), which are the components of this TFP measure. Considering inefficiencies will then allow the effects of these variables on TFP growth to be estimated via technological progress and efficiency gains.

Notizen: Abstract A consistent gap exists between home Internet use in metropolitan areas and in non-metropolitan areas in the U.S. This digital divide may stem from technology differences in home Internet connectivity. Alternatively, differences in education, income, and other household attributes may explain differences in metropolitan and non-metropolitan area home Internet access. Effective programs to reduce the metropolitan–non-metropolitan digital divide must be based on an understanding of the relative roles that technology and household characteristics play in determining differential Internet usage. The household Internet adoption decision is modeled using a logit estimation approach with data from the 2001 U.S. Current Population Survey Internet and Computer Use Supplement. A decomposition of separate metropolitan and non-metropolitan area estimates shows that differences in household attributes, particularly education and income, account for 63 percent of the current metropolitan–non-metropolitan digital divide. The result raises significant doubts that policies which focus solely on infrastructure and technology access will mitigate the current metropolitan–non-metropolitan digital divide.

Notizen: Networks of interaction have assumed particular significance in recent years because of their presumed importance for learning and innovation. Alliances between related firms are thought to encourage interactive learning between participating organizations through the sharing of knowledge and information, which is itself facilitated through trust, shared values and ways of working. The vast body of literature that has emerged is, however, incredibly fragmented, encompassing an array of theoretical positions and perspectives. This paper focuses upon two issues which are believed to be of particular significance and which need clarification in order to move to a clearer understanding of the ways in which networks of interaction evolve, and of their capabilities and limitations in relation to economic performance and competitiveness: (1) the importance of network structure, arguing that innovative activity requires flexibility with regard to network formation. (2) The role of geography in relation to the construction and functioning of alliances. It is the contention here that networks are likely to be increasingly international in scope.

Notizen: Constantinos I. Chlomoudis and Athanasios A. Pallis, European Union Port Policy: The Movement Towards A Long Term Strategy

Notizen: This paper explores possible ways in which growth in Internet retailing (e-retailing) may affect the spatial distribution of economic activities. After a brief overview of e-retailing, a categorization of possible spatial impacts is introduced. These include impacts on the retail industry, such as substitution of e-retail for brick-and-mortar retail, impacts on transportation, such as substitution of freight transportation for personal transportation in goods delivery, and pervasive impacts that affect the whole economy. The latter category includes uniform delivered pricing, spatial leveling of accessibility, and marketing strategies that target individuals rather than regions. The question of whether e-retailing and brick-and-mortar retailing are truly substitutes is taken up in the next section, along with potential implications of multi-channel retailing. The final section of the paper defines some critical research directions.

Notizen: Logistics chains are constantly changing to facilitate increasingly global movements. In qualitative terms, long term trends in logistics services indicate a growing degree of product customization and an increased responsiveness in order delivery. These trends impact on the development of technology and the growth of welfare in different world regions in different ways. This paper drafts a research agenda which will help to improve understanding of the interrelationships between trade, logistics, transport, and regional development at a global scale. Rather than being an exhaustive or detailed inventory of trends, the paper provides a focus on “supply chain by thinking.” The key starting point is the need for more and more efficient transportation and sophisticated logistics processes. Three subjects are treated: First, the strategic implications of borderless supply chain management on the choice of alternative logistics structures in supply chains are considered; second, the possible impacts of the expected changes in supply chain processes upon regional economic activities are examined; third, the impacts of changes in global logistic processes on the transportation system and, in turn, on the environment are explored. This discussion leads to the identification of some new research challenges in the field of transportation and logistics.

Notizen: The question “Will using Information and Communication Technology (ICT) systems enable a more sustainable mobility?” is answered through analyzing current ICT policy in the EU and the United States of America (USA), through developing a conceptual model to structure the expected direct and indirect effects of ICT systems on mobility, and through building models for three selected ICT systems to estimate their quantitative effects on mobility. Based on the models, ICT systems seem to have limited mobility reduction potential (in terms of CO2 emissions and kilometer savings). On the short term, because of efficiency gains, ICT systems have a positive impact. In the long term, better quality of mobility will attract new demand and this will again result in an increase of travel. For policymakers this implies that ICT systems in the short run can make mobility more efficient. In the long run, to prevent the more efficient mobility from attracting new traffic, the implementation of any ICT system should be accompanied by a stronger pricing policy.

Notizen: Although many studies have investigated how poor health affects hours of work and labor force participation, few have examined the extent to which individuals adapt in order to remain in the labor market. Individuals experiencing health problems may move to different types of work in order to remain in the labor force or to reduce the negative labor market consequences of illness. This paper investigates the movement between employers, and among occupation categories when changing employers, using data from the Health and Retirement Study (HRS). One advantage of the HRS is that its questions on life-cycle employment and health patterns permit a long-term perspective on job mobility that is unavailable in most other datasets. Workers with health problems are more likely than healthy workers to remain with their current employer than to switch employers. But among those who switch employers, those with health problems are more likely to change broad occupational categories than are healthy workers. While many individuals remain with the same employer after the onset of health problems, many do switch employers and occupations, even in the presence of ADA legislation.

Notizen: This paper examines how the presence of dual, disparate environmental disamenities located near each other impact property values in a semi-rural area. A heavy metals manufacturing facility and a rubber-compounding factory operate two and one half miles apart in a small community. The heavy metals manufacturing facility uses low-level depleted uranium in its production. The level of production is small and the production process does not emit visible air pollution or odors that can be easily identified. Thus, if the surrounding community negatively perceives a potential risk, it is not through the channels of sight or smell. The rubber-compounding factory emits foul odors and some visible air pollution. Thus, its negative externalities and potential risks are easily perceptible. Using the hedonic price technique, this paper examines the impact of the use of a non-perceptible hazardous material in the production of a good on housing prices in a community when another more visible, noxious facility is present. The results show that noticeable disamenities are capitalized into housing values, while non-visible ones are not.

Notizen: This paper presents some micro-evidence relevant to the “Porter Hypothesis” on the techno-economic consequences of Austrian Volatile Organic Compound (VOC) emission standards, the most restrictive of their kind in the world. Using firm-level survey data and complementing it with highly disaggregated foreign trade data, the paper explores whether the standards had a palpable impact on the competitiveness of Austrian manufacturers of paints, coatings, printing inks, and adhesives, whether compliance stimulated innovation in this industry, whether the standards crowded out other, more productive Research and Development (R&D), and whether compliance efforts gave rise to unexpected benefits of compliance. It finds no unequivocal aggregate impact on the competitiveness of regulated firms, yet does find some interesting variation with firm size. Moreover, the standards appear to have dampened import competition. The standards gave rise to considerable changes in firms’ product range and appear to have accelerated the rate of product innovation in the regulated industry. R&D spending to develop compliant products is found to be very unevenly distributed, mainly due to technological and, to a lesser extent, organizational factors. There is evidence that compliance efforts displaced or postponed existing R&D projects. However, there is also evidence that search for compliant products yielded unexpected and beneficial ideas, knowledge, and competencies.

Notizen: Abstract Mobility is a necessary condition for the social and emotional well-being of older people. To meet their mobility needs, the elderly assign pivotal importance to the automobile despite the potential challenge of driving cessation and searching for alternatives to automobile transportation. Older persons’ generally strong reliance on the automobile varies, however, by land use patterns (density) as well as by demographic and socioeconomic characteristics. This paper analyzes the effects of spatial context and personal attributes on automobile reliance among the elderly. Using the 1995 Nationwide Personal Transportation Survey (NPTS) trip data, two models of automobile reliance among elderly (65+) trip makers are estimated. The results show that spatial context effects of automobile reliance vary by demographic characteristics; in particular, they are more pronounced for black than for white elderly. Moreover, race variation in automobile reliance is strongest in urban locations rather than less dense spatial contexts. Finally, the differentiation between being a passenger rather than a driver is salient in order to understand locational and racial variations in automobile reliance among the elderly.

Notizen: Abstract This paper examines the relationship between quality of life, rural development, and several socioeconomic variables. The analysis utilizes data obtained from a survey questionnaire administered to a random sample of more than 2,000 residents in West Virginia, and spatial data obtained by geocoding the survey respondents’ addressees. Quality of life is measured by a three-point categorical measure of overall satisfaction, and development is measured by a goods and services availability index. A simultaneous ordered probit model is used to examine the relationships. The empirical results are consistent with the theoretical predictions and indicate a simultaneous relationship between quality of life satisfaction and rural development.

Notizen: Producer services have been among the most rapidly growing industries, as measured by employment, in the United States and in Europe in recent decades. The production and delivery of these specialized forms of service industry work require the use of transportation and communications systems in a variety of ways, including the physical movement of people working in these industries, as well as the movement of the information related to the production and distribution of their work. Some of this work is performed in localized markets, requiring travel between clients and suppliers in local transportation modes, such as auto, bus, or other types of transportation. Other work is done by specialists who travel interregionally and globally to do their work, primarily traveling to their clients. There is little knowledge of how these production relationships have changed with the advent of the Internet and the widespread use of e-mail in the business production process. Within the framework of this STELLA initiative, this paper outlines research needs in this area, and frames an approach that would produce badly needed knowledge about impacts on the producer services of the Internet and related e-commerce initiatives on physical transportation systems at a local to interregional scale.

Notizen: This paper presents the results of a microanalysis of freight transport demand in a logistics context. Current research concentrates, with few exceptions, on shippers’ choice of a transport mode. However, in a global context, shippers’ behavior has to be conceived as a complex decision, which considers transport mode choice as only a part of a firm's logistics strategy. Since no data exist to directly estimate the marginal values for different qualities of transport and logistics services, a stated preference approach is applied. Adaptive stated preference experiments were performed for twenty-two firms in Italy and in Switzerland. The experimental results—forty hypothetical binary choices per firm—were completed by background information on the firms’ long-term logistics strategies. The results confirm the relevance of the logistics context (e.g., JIT strategies on the supplier's or customer's side) for transport demand. The calculated marginal values of time and characteristics (reliability, frequency, etc.) provide important insights and permit generalized costs in freight transport models to be recalibrated.

Notizen: The 1990s witnessed an enormous wave of mergers and acquisitions dramatically reconfigure the market structure of global telecommunications. In Europe and the U.S., telecommunications firms have steadily consolidated into a shrinking pool of providers, rapidly oligopolizing the industry. This paper reviews the number and size of mergers and acquisitions globally in the 1990s and charts the national patterns of purchasers and target firms, noting the overwhelming hegemony of American corporations. The reasons behind this process include globalization, deregulation, the convergence of digital technologies, the search for economies of scale and scope, and U.S. corporate tax laws. It also points to the impacts of this oligopolization on consumer prices, labor, equity of access to telecommunications services, and the political and cultural repercussions of increasingly concentrated ownership.

Notizen: Abstract The dramatic evolution of global finance in the last three decades has seen intensified competition among the world's major cities to become prominent control centers of global financial flows. This paper examines the spatial organization and evolution of capital markets in forty-three world cities from 1980 to 1998. It finds evidence of the strengthening of hierarchical tendencies among world financial and capital cities as they search for ways to differentiate between themselves through financial concentration and productivity. The results also indicate a trend towards the dominance of London and New York in this financial hierarchy, and that top tier cities tend to be characterized by significantly lower levels of market and share concentrations, share trading value, and risks. Finally, important differences in ownership patterns between the capital markets are detected for the top cities of the hierarchy.

Notizen: New businesses are highly involved in innovative activity, which enhances worker productivity and leads to increased economic output. This paper investigates the effects of industry concentration on the incidence of new business openings in the 5,504 Maine county-industries. Empirical findings indicate that new business activity increases with the number of incumbent establishments in a county-industry and its concentration level relative to the U.S. economy. Model simulations show that raising county-industries, with no initial industry presence, to concentration levels similar to that of the industry in the U.S. economy results in a 1.7 to 8.9 percent increase in the expected number of business openings over a three-year period. Empirical results also suggest that industry clusters comprised of young and small establishments are more conducive to new business formation than clusters made up of mature and large companies.

Notizen: The effects on wage growth of management practices applied on public lands in the Northern Forest region of the United States are quantified. A central objective is to determine if the management of public lands for preservationist uses results in lower average wages. This is a frequent claim made by critics of land preservation who argue that preservationist management, by prohibiting resource extraction, causes the composition of employment to shift from high-wage jobs in resource-based manufacturing to low-wage jobs in the service sector. A model of simultaneous employment and net migration growth is estimated with data on non-metropolitan counties over the period 1990 to 1999 and applied in a recursive relationship to wage growth. In earlier studies, models of this type have typically been specified in levels. Time-series evidence that supports a preference for growth rates is provided as the form for such models. Exogenous variables in this model include the 1990 shares of the county land base that are publicly owned and managed for preservationist (non-extractive) uses and multiple (including extractive) uses. It was found that wage growth rates are not significantly affected by the shares of land under either management regime. As well, recent declines in national forest timber sales are found to have no effect on wage growth.

Notizen: In this paper we examine dynamic relationships among wheat prices from five countries for the years 1981–1999. Error correction models and directed acyclic graphs are employed with observational data to sort–out the dynamic causal relationships among prices from major wheat producing regions: Canada, the European Union, Argentina, Australia, and the United States. An ambiguity related to the cyclic or acyclic flow of information between Canada and Australia is uncovered. We condition our analysis on the assumption that information flow is acyclic. The empirical results show that Canada and the U.S. are leaders in the pricing of wheat in these markets. The U.S. has a significant effect on three markets excluding Canada.

Notizen: Under certainty, unlimited duration of private ownership of land provides landowners with efficient development incentives. However, in cases of ownership risk arising from title mistakes, fraud, boundary encroachment, or adverse possession, the statute of limitations sets a limit on how long agents have to establish or defend an ownership claim. This paper demonstrates that such restrictions speed the pace of land development and systematically affect the development density according to site location in the urban land market. It also offers an explanation of why land owners prefer a time limit on the ability to defend their ownership. It shows that the value–maximizing statute varies across sites in the spatial market.

Notizen: Predictions of the portfolio model of the economy are tested using regional growth data from Europe. It is shown that more aggregated regions of Europe tend to be more economically diverse than more disaggregated regions. Then, using different frontier estimation methods, evidence of a convex growth–instability frontier for aggregated regions is presented. At the most regionally disaggregated level for which there are data, there is weak if any evidence of the frontier. The results suggest that large economies are appropriately modeled as portfolios, whose growth processes are characterized by the convex growth–instability frontier, whereas small local economies do not display this characteristic.

Notizen: In this paper, I examine the ways in which widely reproduced discourses and theories about globalisation elide American dominance. Drawing on arguments about enframing made by Timothy Mitchell in his postcolonial analysis of Egypt's colonisation, I suggest that one significant cause of this elision relates to a commonplace imagined geography of globalisation that enframes economic interdependency as constitutive of a smooth, decentred and somehow levelled global space of flows. I argue that this imagined geography is structured into dominant political-economic forms of practice and governance, and that in this way it both enables and elides American dominance. Notwithstanding this force in the world, and notwithstanding the tendency of many commentators on globalisation to ignore American dominance, recent events have made such elisions more difficult. I therefore suggest that we need to do more to theorise how American dominance is interwoven with economic globalisation.

Notizen: This paper examines the fieldwork undertaken by the distinguished French geographer Pierre Gourou (1900–99) in the Tonkin Delta (Red River Delta) of northern Vietnam in the 1920s and 1930s, and his wider configuration of “the tropical world” as a distinct space of knowledge and radical otherness. Gourou's fieldwork endeavours in French Indochina are interpreted in the light of recent work on “tropicality”: the idea that “the tropics” need to be understood as a western cultural construction and colonising discourse that essentialised the hot, wet regions of the world, and exalted the temperate world over its tropical counterpart. The paper focuses on Gourou's monumental 1936 study Les paysans du delta tonkinois, étude de géographie humaine. It is argued that in this study, and his later comparative work on the tropics, Gourou elaborated a distinct geographical variant of tropicality, but one that, ultimately, reinforced the essentialist logic and momentum of this discourse. Particular attention is paid to the geographical ideas, fieldwork techniques and discursive strategies that Gourou used in his 1936 study, and the French colonial context in which he worked. The article shows how Gourou appealed to western reason and science as tools of study, identified overpopulation as the key problem facing the Tonkin Delta, and suggested that colonial practices of modernisation had a limited place and ineffectual role in the rice plains of the region.

Notizen: Through a re-reading of my Ph.D. fieldwork on Cuba's biotechnology industry, I empirically pull apart the relationship between fieldwork practice and knowledge production as experienced in my research. I argue that reflexivity is an insufficiently critiqued concept and, as a result, that its widespread influence in contemporary fieldwork practice works to obscure the influence of “others”, not just on the “doing” of research but on the conceptual development of the methodology itself. I make this argument by focusing on the various strategies I employed to actualise my research methodology, the problems I met with and the subsequent pull of my research in new directions. I cover such issues as gaining access, working in multiple locales across antagonistic polities, what happens when fieldwork goes wrong and the notion of “empirical drift”. I use these issues to examine how I was actively constructing both my field and my research methodology at the same time and through others. I try to show how the fact that fieldwork can be simultaneously a lived experience, a socially constructed performance and an episteme accounts for much of its distinctive qualities as a milieu in which existing knowledge is put to the test, or added to. I argue that these same qualities allow it to be a deeply intertextual process, or a joint work between the researcher and the field. This, I suggest, warrants greater recognition.

Notizen: This paper considers disjunctures between my expectations and experience of doing dissertation fieldwork, which I conducted in Benin between the autumns of 1997 and 1998. The research examined the nature of women's livelihood strategies and their associated outcomes in terms of material well-being. I now believe that my feminist worldview, and my growing exhaustion as the project progressed, resulted in my minimising the importance of key aspects of fieldwork in an African context. Specifically, I downplayed the importance of negotiating with male “gatekeepers” in gaining access to the women with whom I wanted to work. While most of the time I was able to manage this well enough, one day, in particular, stands out as a time when I handled these negotiations very poorly. This paper compares the experiences of that day with another much more productive and fruitful one to examine how and why expectations and experience can diverge. A consideration of some of the issues that resulted in the “lost day” might prove instructive for other researchers.

Notizen: This paper considers some practical problems associated with organising large-scale comparative field research in eastern India. The focus of the paper is on the use of brainstorming and “modified logframes” as two means by which hypotheses about the working of the local state from the point of view of the rural poor could be turned into concrete field questions. The paper is less concerned with ethical and positional issues relating to team-based research in “the tropics” (on this, see Williams et al., 2003a) than with the equally important if apparently more prosaic issues relating to the flawed but necessary search for objectivity and rigour in comparative field studies.

Notizen: The subjectivity of individuals, the so-called speakers and hearers of political discourse, who actually, or even ideally, populate a state, needs to be understood in terms of enunciative modalities - the statuses, sites, and positions - of their existence as political subjects. Enunciative modalities refer to the ways a discursive practice is attached to bodies in space (Clifford, 2001:56).Governmental thought territorializes itself in different ways… We can analyze the ways in which the idea of a territorially bounded, politically governed nation state under sovereign authority took shape… One can trace anomalous governmental histories of smaller-scale territories… and one can also think of these [as] spaces of enclosure that governmental thought has imagined and penetrated… how [does it] happen that social thought territorializes itself on the problem of [for example] the slum in the nineteenth century (Rose, 1999:34–36)?

Notizen: Books reviewed:Nancy Leys Stepan, Picturing Tropical NatureAnne-Marie Hilsdon, Martha Macintyre, Vera Mackie and Maila Stivens (eds.), Human Rights and Gender Politics: Asia-Pacific PerspectivesElisabeth Croll, Endangered Daughters: Discrimination and Development in AsiaTai Yong Tan and Gyanesh Kudaisya, The Aftermath of Partition in South AsiaHal Hill and Joaõ M. Saldanha (eds.), East Timor: Development Challenges for the World's Newest NationRobert E. Rhoades (ed.), Bridging Human and Ecological Landscapes: Participatory Research and Sustainable Development in an Andean Frontier

Notizen: Abstract Clustering of economic performance across jurisdictions has generated considerable research on the spillovers and linkages among geographical neighbors. Much of this work, however, has been aspatial, implying that the influence of location attributes on growth has been largely ignored. In this paper, we examine the contribution of location to regional economic growth using municipio-level data for the Brazilian Northeast—a historically lagging region of the country. We test if productivity among northeastern municipios is converging to a steady state and whether spatial externalities are linked to productivity growth in individual municipios. We find that, conditional on structural characteristics, productivity among municipios is converging at about 3 percent per year. Further, productivity in individual municipios is positively associated with own-structural characteristics but negatively associated with productivity growth in neighboring municipios. This means that there are negative spatial externalities coming from productivity improvements in neighboring regions.

Notizen: Abstract The objective of this research is to investigate dimensions of geographic variation in spatial dependency contained within large multilevel data sets. We calculate 1990 population density by census block group, county, and state for the 48 coterminous states and the District of Columbia of the United States, calculations of interest to a wide variety of spatial scientists. We explore relations between these levels and their variation across the nation. The empirical findings generated by this work furnish implications concerning the Modifiable Areal Unit Problem (MAUP), spatial autocorrelation statistics, scale effects, and resolution.

Notizen: Abstract How do firms in nonrenewable resource industries respond to changes in state taxes? This paper presents simulations of changes in state production (severance) tax policy on the timing of exploration and output in Wyoming. The framework developed allows for interactions between taxes levied by different levels of government. Results suggest that oil production is highly inelastic with respect to changes in production taxes. Policy implications suggest that increases in production taxes on oil risk little loss in future production. The extent to which these results may generalize to other oil producing states is considered. JEL Codes: H71, Q32

Notizen: Books reviewed in this article:Michael L. Lahr and Erik Dietzenbacher (eds.), Input-Output Analysis: Frontiers and ExtensionsA. Stewart Fotheringham, Chris Brunsdon and Martin Charlton, Geographically Weighted Regression: The Analysis of Spatially Varying RelationshipsIsabelle Thomas, Transportation Networks and the Optimal Location of Human Activities: A Numerical Geography ApproachVolker M. Welter, Biopolis: Patrick Geddes and the City of LifeAnthony Tung, Preserving the World's Great Cities: The Destruction and Renewal of the Historic MetropolisJanet Rothenberg Pack, Growth and Convergence in Metropolitan AmericaJeffrey M. Sellers, Governing from Below: Urban Regions and The Global EconomyHarri Andersson, Gertrud Jorgensen, Dominique Joye and Wim Ostendorf (eds.), Change and Stability in Urban Europe: Form, Quality and GovernanceLaura Reese and Raymond A. Rosenfeld, The Civic Culture of Local Economic DevelopmentGrant Ian Thrall, Business Geography and New Real Estate Market AnalysisMary-Françoise Renard, China and Its Regions: Economic Growth and Reform in Chinese Provinces

Notizen: Abstract This study examines the effects of the risk from transporting high–level radioactive waste to the proposed Yucca Mountain repository on housing location decisions in Southern Nevada. Using data from a survey of southern Nevada households, we develop a model–based subjective risk estimate for each household. We then explore different factors that may influence the household's location decisions if the proposed transportation route is ultimately chosen for nuclear waste transport. We extend the conventional expected utility model to allow for uncertainty surrounding the actual risks borne by the household. Finally, we examine the impact of federal government compensation on households’ location decisions. The findings indicate that residents currently living near the proposed transportation route express subjective risk estimates much larger than those reported by the Department of Energy. In general, households that are uncertain about the future risks are more likely to relocate than those expressing certainty. When everything is considered, the model predicts that between one and three percent of households living near the transportation route are likely to relocate. Compensation can influence some households to remain at their present location and bear the transport risk.

Notizen: Abstract In this paper we investigate whether it is preferable for Canadian regions to individually adopt the U.S. dollar or to remain with the current currency arrangement. The empirical analysis focuses on the cross–correlations of various business cycle measures of Canadian regions, of Canada, and of the United States. The business cycle investigation is completed by the analysis of two other important criteria for optimum currency areas, industrial specialization and trade interdependence. Our results highlight a significant heterogeneity across Canadian provinces. In particular, it transpires that it could be economically advantageous for the central provinces of Ontario and Quebec and to a lesser extent British Columbia to adopt the U.S. dollar. In contrast, it is not as clear what the other regions should do, the final answer depending on the path the larger three provinces take.

Notizen: Abstract This paper examines the robustness of various models of spatial autocorrelation through a series of Monte Carlo experiments in which each model takes a turn at the data generator. The generated data are then used to estimate all of the models. The estimated models are evaluated primarily on their predictive power.

Notizen: Abstract This paper argues that new immigrants cluster in culturally homogeneous groups in the host country because of imperfect information. However, a pulling effect exists provided that the cultural communities are not too large. With a panel of migration flows to the major O.E.C.D. countries from the mid 1980s to the mid 1990s, it is shown that the existence of similar cultural communities attracts new immigrants. However, the effect is not homogeneous for all types of source and destination countries. Furthermore, the pulling effect is shown to fall to zero for cultural communities above a certain threshold size.

Notizen: Abstract This study extends the work of Estrella and Mishkin (1996, 1998) to show that interest-rate spreads and probit modeling can be used to predict recessions in many states as well as the nation. State recessions are defined as two or more consecutive quarters of declining real gross state product. The yield spread, SPREAD, is defined as the difference between the 10-year Treasury bond rate and the three-month Treasury bill rate. The national results are similar to those obtained by Estrella and Mishkin. Probit models are estimated for all 50 states using SPREAD and unemployment insurance claims, UI, as alternative explanatory variables. For 34 of the 50 states, SPREAD is significant at the 0.01 level as a predictor of state recessions. Much weaker results are obtained using UI. Simulations for the 1979–2001 period are used to compute loss functions for the national and state models at probability screens of 30, 40, 50, and 60 percent. The results demonstrate that probit models based on SPREAD can be useful in improving business and policy decisions in many states.

Notizen: This paper departs from previous work on the locational effects of business taxes under uncertainty by considering the attainment of long–run industry equilibrium. A general m input, planar–space production location model is adopted, and each individual firm is assumed to face random industry demand. I provide some interesting results which are contrary to those proposed by previous studies in the single–firm context and the relative impact of various business taxes.

Notizen: In this paper a novel modular product unit neural network architecture is presented to model singly constrained spatial interaction flows. The efficacy of the model approach is demonstrated for the origin constrained case of spatial interaction using Austrian interregional telecommunication traffic data. The model requires a global search procedure for parameter estimation, such as the Alopex procedure. A benchmark comparison against the standard origin constrained gravity model and the two–stage neural network approach, suggested by Openshaw (1998), illustrates the superiority of the proposed model in terms of the generalization performance measured by ARV and SRMSE.

Notizen: Books reviewed in this article:Carl Abbott, Greater Portland: Urban Life and Landscape in the Pacific NorthwestMassimo Gastaldi and Aura Reggiani, New Analytical Advances in Transportation and Spatial DynamicsManfred M. Fischer and Josef Frohlich (eds.), Knowledge, Complexity and Innovation SystemsMarlon G. Boarnet and Randall Crane, Travel by Design: The Influence of Urban Form on TravelStephen Graham and Simon Marvin, Splintering Urbanism: Networked Infrastructures, Technological Mobilities and the Urban ConditionWilbur R. Maki and Richard W. Lichty, Urban Regional Economics: Concepts, Tools, ApplicationsGerald D. Nash, The Federal Landscape: An Economic History of the Twentieth–Century WestWilliam G. Robbins and James C. Foster (eds.), Land in the American West: Private Claims And The Common GoodGeoffrey P. Meen, Modelling Spatial Housing Markets: Theory, Analysis, and PolicyWilliam P. Browne, The Failure of National Rural Policy: Institutions and InterestsMartha Burt, Laudan Y. Aron, and Edgar Lee, with Jesse Valente, Helping America's Homeless: Emergency Shelter or Affordable Housing?David Pitfield (ed.), Transport Planning, Logistics, and Spatial Mismatch: A Regional Science PerspectiveHarvey J. Miller and Shih–Lung Shaw, Geographic Information Systems for Transportation: Principles and ApplicationsBoris A. Portnov and Evyatar Erell, Urban Clustering: The Benefits and Drawbacks of LocationPhilip McCann, Urban and Regional Economics

Notizen: Abstract Computable general equilibrium (CGE) models are often criticized for using restrictive functional forms and relying on external sources for parameter values in their calibration. CGE modelers argue that in many instances reliable econometric estimates of important model parameters are unavailable because they must be estimated using small numbers of time-series observations. To address these criticisms, this paper uses a Bayesian approach to estimate the parameters of a translog production function in a regional computable general equilibrium model. Using priors from more reliable national estimates, and parameter restrictions required by neoclassical production theory, estimation is done by Markov chain Monte Carlo simulation. A stylized regional CGE model is then used to contrast policy responses of a Cobb-Douglas specification with those from the estimated translog equation.

Notizen: Abstract Many theoretical models analyze the effects of decentralized environmental policymaking. The predictions range from a race to the top, a race to the bottom, or no effect. However, little empirical evidence exists to resolve this ambiguity. This paper fills the void by examining the impact of decentralized environmental policymaking in the U.S. under Presidents Ronald Reagan and George H.W. Bush. For abatement expenditures, Reagan's decentralization had no discernible impact before the mid-1980s, but by the mid-1980s the data are consistent with decentralization leading to a race to the top. No statistically significant effect is found on nitrogen oxide or sulfur dioxide emissions.

Notizen: Abstract Using data from the National Longitudinal Survey of Youth 1979, this study examines the pattern of early career job mobility and migration in a sample of young male workers. Primary interest lies in the between–job wage change accompanying job transitions as well as the extended time–profile of migrant earnings. When the sample of job transitions is partitioned by education level, contemporaneous returns are found only for workers with twelve or less years of completed schooling. In contrast, highly educated workers demonstrate significant extended returns to migration with the bulk of pecuniary rewards accruing with a lag of nearly two years.

Notizen: Books reviewed in this article:Masahisa Fujita and Jacques-François Thisse, Economics of Agglomeration: Cities, Industrial Location, and Regional GrowthTimothy J. Bartik, Jobs for the Poor: Can Labor Policies Help?Miriam Solomon, Social EmpiricismNicole Pohl, Mobility in Space and Time: Challenges to the Theory of International EconomicsSteven Brakman, Harry Garretsen, and Charles van Marrewijk, An Introduction to Geographical Economics: Trade, Location and GrowthBruce A. Weber, Greg J. Duncan, and Leslie A. Whitener (eds.), Rural Dimensions of Welfare ReformWallace E. Oates (ed.), Property Taxation and Local Government Finance: Essays in Honor of C. Lowell HarrisMaryann P. Feldman and Nadine Massard (eds.), Institutions and Systems in the Geography of InnovationDengjian Jim, The Dynamics of Knowledge Regimes: Technology, Culture and Competitiveness in the USA and JapanHarvey J. Miller and Jiawei Han (eds.), Geographic Data Mining and Knowledge DiscoveryAnna Nagurney and June Dong, Supernetworks: Decision-Making for the Information AgeStuart McCook, States of Nature: Science, Agriculture, and Environment in the Spanish Caribbean, 1760-1940Philip Scranton (ed.), The Second Wave: Southern Industrialization from the 1940's tothe 1970'sStephen Haycox, Frigid Embrace: Politics, Economics, and Environment in AlaskaKathleen Ann Pickering, Lakota Culture, World EconomyOrganisation for Economic Co-operation and Development (OECD), OECD Territorial Reviews: HungaryOrganisation for Economic Co-operation and Development (OECD), OECD Territorial Reviews: ItalyOrganisation for Economic Co-operation and Development (OECD), OECD Territorial Reviews: Bergamo, ItalyOrganisation for Economic Co-operation and Development (OECD), OECD Territorial Reviews: Teruel, SpainOrganisation for Economic Co-operation and Development (OECD), OECD Territorial Reviews: The Valencian Central Districts, SpainJaakko Suvantola, Tourist's Experience of Place

Notizen: Abstract This paper is an inquiry into the optimal allocation of time and natural areas to recreational uses, which have the feature of being a pure and continuous public good. We address this issue with a comprehensive approach. A static rational general equilibrium framework is developed in which heterogeneous agents allocate land and time endowments between alternative uses. This modeling has important advantages. First, Pareto-optimal and voluntary-contribution equilibrium allocations are obtained in a unified set-up. Second, the suboptimality result of the decentralized equilibrium, the free-rider problem on the provision of this nonexcludable public good, and different mechanisms to return the economy to its first-best are analyzed. Finally, a methodological critique is made of some empirical literature, and it is suggested that our theoretical microeconomic-based structure seems to be a suitable starting point for empirical research.

Notizen: Abstract The impact of the recent Customs Union (CU) agreement between Turkey and the European Union on internal migration is studied using an intra-industry trade Computable General Equilibrium (CGE) model with intersectoral capital mobility under two alternative specifications for the labor market: the traditional Harris-Todaro approach and the existence of a “wage curve” in the urban sector. Under both specifications, the numerical results show that the CU is welfare enhancing and causes a reduction of the urban-rural wage gap as suggested by theoretical studies. At the same time, it leads to rural-to-urban migration and raises the capital rent, results that are counter intuitive with respect to the dual economy literature. Furthermore, the rise in formal labor demand and the migration response to the CU have not resulted in an increase in urban unemployment (i.e. the “Todaro paradox”), but rather to a fall in the unemployment pool. The study also shows that the Bhagwati-Srinivasan proposal of maximizing welfare by uniformly subsidizing the entire labor market is impracticable, especially if the high wage union sector can negotiate employment conditions.