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  • Immunocytochemistry  (117)
  • Noctuidae  (92)
  • Rat
  • Springer  (270)
  • American Chemical Society
  • Elsevier
  • 1990-1994  (126)
  • 1985-1989  (144)
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Year
  • 1
    ISSN: 1432-0878
    Keywords: Atrial natriuretic peptide ; Ventricular myocytes ; Atrial myocytes ; Cell culture ; Secretion ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary We have demonstrated that atrial natriuretic peptide-like immunoreactivity is stored and secreted by ventricular and atrial myocytes in dissociated cell culture preparations from the heart of newborn rat. Culture preparations were maintained in either foetal calf serum-supplemented medium 199 or in hormone-supplemented, serum-free medium 199. The presence of atrial natriuretic peptidelike immunoreactivity in the cultured myocytes was demonstrated at both light-and electron-microscopical levels. Release of atrial natriuretic peptide-like immunoreactivity into the culture medium was measured by radioimmunoassay; molecular forms of the stored and secreted peptide were determined by gel column chromatography. The atrial natriuretic peptide-like immunoreactivity of cultured atrial and ventricular myocytes was concentrated in the perinuclear cytoplasm and was localised to electron-dense secretory granules. The number of immunoreactive ventricular myocytes and the intensity of their immunofluorescence changed with time in culture and was higher in cultures in foetal calf serum-supplemented medium than in serum-free medium. Gamma-atrial natriuretic peptide was stored and released by cultured atrial and ventricular myocytes, but was broken down to alpha-atrial natriuretic peptide in the growth medium. This process was foetal calf serum-independent, since it occurred in both the media used, indicating that cardiac myocytes in culture may release a factor that cleaves gamma-atrial natriuretic peptide to form alphaatrial natriuretic peptide.
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  • 2
    ISSN: 1432-0878
    Keywords: Hypothalamus ; Neurosecretion ; Vasotocin-neurophysin precursor ; Immunocytochemistry ; Lectin histochemistry ; Snake, Natrix maura ; Lizard, Liolaemus cyanogaster
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The immunocytochemical and lectin-binding properties of the magnocellular neurosecretory neurons in the hypothalamus of 2 reptilian species, the snake Natrix maura and the lizard Liolaemus cyanogaster, were investigated. Particular attention was paid to the secretory droplets present in these neurons. Antisera against bovine neurophysins I+II, arginine-vasotocin, and mesotocin were used. The following lectins were applied: concanavalin A (Con A), wheat-germ agglutinin (WGA), and Limax flavus agglutinin (LFA). Adjacent 1-μm-thick methacrylate sections were used to investigate the same secretory neuron and the same colloid droplets with all three antisera and all three lectins. Several sections were treated with trypsin and urea before immunostaining or lectin binding. Con A bound to both vasotocin- and mesotocin-immunoreactive neurons, WGA exclusively to vasotocin neurons; neither of these neurons reacted with LFA. The colloid droplets were present in vasotocin neurons but absent in the mesotocin neurons. These secretory droplets showed an affinity for Con A but not for WGA, and reacted with antisera against neurophysins and vasotocin. In Natrix maura, the colloid droplets became reactive with Con A and the antisera used only after pretreatment of the sections with trypsin and urea. Within the hypothalamo-neurohypophyseal system, antiserum against vasotocin and WGA revealed the same fiber bundles. It is concluded (i) that in reptiles the vasotocin-neurophysin precursor is glycosylated, (ii) that vasotocin neurons have the exclusive capacity to form colloid droplets, and (iii) that these droplets are an intracisternal (RER) storage form of the vasotocin-neurophysin precursor.
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 52 (1993), S. 361-364 
    ISSN: 1432-0827
    Keywords: Calcitonin ; Sustained release ; Copolymer depot ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Studies were carried out to determine whether monolithic depot formulations, prepared using lactide:glycolide copolymers, could be used to administer salmon calcitonin (sCT) to rats in vivo. Formulations containing 2, 5, or 10% (w/w) sCT were administered subcutaneously to female Wistar strain rats. Release of sCT was determined by measurement of peptide in plasma using a specific radioimmunoassay and by measurement of residual sCT in the depots after recovery at postmortem. Plasma calcium concentrations and cumulative weight gain of the animals were used to measure pharmacological effects of the released sCT. Release of sCT from the depots was controlled by the copolymer and was sustained for periods up to 10 days. However, the release of sCT from the depots did not significantly alter plasma calcium concentrations, and effects on cumulative weight gain were small and transient. Peptide loading of the formulations was shown to modify sCT release. Maximal release of sCT from depots containing 10% peptide occurred over a 7 to 14-day period postadministration, with 5% sCT release occurred between days 11 and 14, and with 2% sCT, the period of maximal release was between days 11 and 18. Release of peptide from the depots was essentially complete by 21 days postadministration irrespective of the peptide loading. These data suggest that lactide:glycolide copolymer depots may have application for the convenient clinical administration of sCT in metabolic bone diseases.
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  • 4
    ISSN: 1432-0878
    Keywords: Hepatocytes ; Lysosomes ; Macroautophagy ; Microautophagy ; Starvation ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Ultrastructural morphometric analysis was used to study time-dependent variations in macro and microautophagy in rat hepatocytes. Except during periods of shortterm starvation for up to 24 h, animals were kept under standardized conditions of food intake. In hepatocytes of meal-fed rats the volume fraction of macroautophagic vacuoles is significantly higher at 23:00 h, i.e., immediately before food intake, compared to 11:00 h, i.e., 12 h following feeding. During fasting, macroautophagy drops to a low level. Microautophagic vacuoles in hepatocytes of meal-fed rats, sacrificed at 11:00 or 23:00 h respectively, do not show any significant quantitative differences. However, during 12 h of starvation, the volume fraction of microautophagic vacuoles rises significantly, whereas the numerical density remains constant. Subsequently, during the second 12-h period of fasting, the volume fraction of microautophagic vacuoles remains unchanged, but the numerical density increases. Over a period of 24 h of starvation the volume fraction of the total lysosomal system does not change significantly, whereas the numerical density rises. The time-dependent changes of the macroautophagic vacuolar system correlate with the circadian, food-related variations in the protein content of individual hepatocytes from meal-fed animals. The increase in volume fraction and thereafter in number of microautophagic vacuoles, as observed during starvation, coincides with a large decrease in protein content of individual hepatocytes.
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  • 5
    ISSN: 1573-1561
    Keywords: Trichogramma pretiosum ; Hymenoptera ; Trichogrammatidae ; Heliothis zea ; Spodoptera frugiperda ; Lepidoptera ; Noctuidae ; sex pheromone ; kairomone ; wind tunnel ; orientation behavior
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The behavior ofTrichogramma pretiosum Nixon wasps when exposed to different olfactory cues was studied in a wind tunnel. Compared to clean air, the sex pheromone of its hostHeliothis zea (Boddie) increased wasp residence times, walking times, and path lengths on a platform and decreased walking velocity. If wasps were released on top of a glass rod above a platform, the odor caused the wasps to land shortly after takeoff. In addition, a clear dose effect with regard to total residence and walking times was found. These responses were not elicited by three dosages of the sex pheromone ofSpodoptera frugiperda (J.E. Smith) or by a blend of saturated acetates. These results correspond with the observation thatH. zea is a common field host ofT. pretiosum, whereas eggs ofS. frugiperda are rarely attacked by this parasitoid.
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Entomologia experimentalis et applicata 56 (1990), S. 23-30 
    ISSN: 1570-7458
    Keywords: Lepidoptera ; Noctuidae ; Mamestra brassicae ; sex pheromone ; calling behaviour ; calling posture ; diel periodicity of calling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé La périodicité quotidienne de l'appel et les effets de l'âge et de la photopériode ont été examinés sur des femelles vierges deMamestra brassicae (Lépido., Noctuidae). Aucun appel n'a été observé pendant la première scotophase; la plupart des femelles appelaient pour la première fois pendant les 2e et 3e scotophases après l'émergence, quelle que fût la photopériode. Les papillons conservés à 16 J/8 N ont commencé à appeler beaucoup plus tard que ceux dont la photopériode était 18 J/6 N. En vieillissant, les papillons appelaient significativement de plus en plus tôt. Avec 16 J/8 N, la moyenne du moment du début de l'appel a diminué de la scotophase 2 à la scotophase 3, après laquelle il s'est stabilisé autour de 260 min après le début de la scotophase. Avec 18 J/6 N, le moment du début de l'appel a diminué jusqu'à la scotophase 4, et s'est stabilisé ensuite autour de 130 min après le début de l'obscurité.
    Notes: Abstract Die periodicity of calling and the effect of age and photoperiod on calling behaviour were studied in virgin females of the cabbage moth,mamestra brassicae L. (Lepidoptera: Noctuidae). No calling activity was observed during the first scotophase. Most females called for the first time during the 2nd or 3rd scotophase after emergence, regardless of the photoperiod. Moths maintained under 16L: 8D started calling significantly later in the scotophase than those maintained under 18L: 6D. With increasing age, moths initiated calling significantly earlier. Under the 16L: 8D photoregime, the mean onset calling time decreased from scotophases 2 to 3, after which it stabilized around ca. 260 min after the start of the scotophase. With 18L: 6D, the onset of calling decreased until scotophase 4, and subsequently stabilized around ca. 130 min after lights off.
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  • 7
    ISSN: 1573-1561
    Keywords: Linear furanocoumarins ; Spodoptera exigua ; Lepidoptera ; Noctuidae ; UV light ; tritrophic interactions ; Bacillus thuringiensis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Acidic fogs with a pH of 2.0 and duration of 2 hr did not reduce the efficacy ofBacillus thuringiensis var.Kurstaki (Berliner). Therefore, the impact of UV radiation was investigated on the interactions between (1) levels of the antibacterial linear furanocoumarins psoralen, bergapten, and xanthotoxin inApium graveolens (L.) occurring following a 2.0 pH acidic fog episode, (2) the noctuidSpodoptera exigua (Hübner), and (3) a sublethal dosage of the microbial pathogenB. thuringiensis var.Kurstaki. Mean time to pupation in the absence of UV radiation (survival was too low to conduct this analysis for insects exposed to UV) was significantly extended by the addition of either psoralens orB. thuringiensis. Larvae developing on diets containingB. thuringiensis plus psoralens required nearly 40% longer to pupate than controls, but their effects were additive as the interaction was not significant. Although the mean times to adult emergence were significantly different, time spent in the pupal stage did not vary significantly between treatments, indicating that increases in larval developmental time were responsible for the observed decrease in developmental rate. Mean time to mortality, a weighted average time of death, was not significantly affected by any of the treatments. In a 2 × 2 × 2 factorial analysis, all main effects (linear furanocoumarins.B. thuringiensis, UV radiation) reduced survival significantly, as did the three-way interaction. Thus, antagonistic interactions with psoralens that would reduce the effectiveness ofB. thuringiensis in the field were not observed. When pairs of main effects were nested within the two levels (presence and absence) of the third factor, several two-way interactions were found. Interestingly, the activity ofB. thuringiensis and the psoralens, individually or in combination, was enhanced by exposure to UV radiation. Implications of this research are discussed for both natural and agricultural ecosystems.
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  • 8
    ISSN: 1432-0878
    Keywords: Gut hormones ; Insulin ; Bombesin ; Immunocytochemistry ; Pancreatic polypeptide ; Cholecystokinin (CCK) ; Gastrin ; Schistocerca gregaria (Insecta)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The endocrine cells of the midgut epithelium of the desert locust are found dispersed among the digestive cells and are similar to those of the vertebrate gut. According to their reactivity to silver impregnation techniques and the ultrastructural features of the secretory granules (shape, electron-density, size, and structure) 10 types of endocrine cell have been identified, of which seven are located in the main segment of the midgut or in the enteric caeca, and the other three seem to be present only in the ampullae through which the Malpighian tubules drain into the gut. The endocrine cells have a slender cytoplasmic process that reaches the gut lumen, a feature that supports the receptosecretory nature postulated for this cellular type in insects as well as vertebrates. Antisera directed against mammalian gastrin, CCK, insulin, pancreatic polypeptide and bombesin reacted with some of the endocrine cells. This is the first time that insulin- and bombesin-like immunoreactive cells have been described in the midgut of an insect.
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  • 9
    ISSN: 1432-0878
    Keywords: Nasal mucosa ; Neuropeptide Y (NPY) ; Vasoactive intestinal polypeptide (VIP) ; Peptide histidine isoleucine (PHI) ; Noradrenaline ; Sympathetic/parasympathetic innervation ; Pig ; Cat ; Guinea-pig ; Rat ; Man
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The occurrence of neuropeptide Y (NPY), vasoactive intestinal polypeptide (VIP) and peptide histidine isoleucine (PHI) in the sympathetic and parasympathetic innervation of the nasal mucosa was studied in various species including man. A dense network of NPY-immunoreactive (IR) fibres was present around arteries and arterioles in the nasal mucosa of all species studied. NPY was also located in nerves around seromucous glands in pig and guinea-pig, but not in rat, cat and man. The NPY-IR glandular innervation corresponded to about 20% of the NPY content of the nasal mucosa as revealed by remaining NPY content determined by radioimmunoassay after sympathectomy. These periglandular NPY-positive fibres had a distribution similar to the VIP-IR and PHI-IR nerves but not to the noradrenergic markers tyrosine hydroxylase (TH) or dopamine-β-hydroxylase (DBH). The NPY nerves around glands and some perivascular fibres were not influenced by sympathectomy and probably originated in the sphenopalatine ganglion where NPY-IR and VIP-IR ganglion cells were present. The venous sinusoids were innervated by NPY-positive fibres in all species except the cat. Dense NPY and DBH-positive innervation was seen around thick-walled vessels in the pig nasal mucosa; the latter may represent arterio-venous shunts. Double-labelling experiments using TH and DBH, and surgical sympathectomy revealed that the majority of NPY-IR fibres around blood vessels were probably noradrenergic. The NPY-positive perivascular nerves that remained after sympathectomy in the pig nasal mucosa also contained VIP/PHI-IR. The major nasal blood vessels, i.e. sphenopalatine artery and vein, were also densely innervated by NPY-IR fibres of sympathetic origin. Perivascular VIP-IR fibres were present around small arteries, arterioles, venous sinusoids and arterio-venous shunt vessels of the nasal mucosa whereas major nasal vessels received only single VIP-positive nerves. The trigeminal ganglion of the species studied contained only single TH-IR or VIP-IR but no NPY-positive ganglion cells. It is concluded that NPY in the nasal mucosa is mainly present in perivascular nerves of sympathetic origin. In some species, such as pig, glandular and perivascular parasympathetic nerves, probably of VIP/PHI nature, also contain NPY.
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  • 10
    ISSN: 1432-0878
    Keywords: Pancreas, endocrine ; Larval development ; Serial thin/semithin sections ; Immunocytochemistry ; Rana temporaria (Anura)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The pancreatic endocrine component was studied at different stages of development in the tadpoles of Rana temporaria. The material was embedded in Epon, and serial semithin and thin sections were made in order to correlate ultrastructural features and tinctorial traits of the endocrine cells. Serial semithin sections were also stained with the peroxidase-antiperoxidase immunocytochemical method and with silver impregnations for argyrophilia and argentaffinity. In early larvae (legless tadpoles), A and B cells are present. Both can be found within ducts and exocrine tissue or, more frequently, in cellular clusters among the ducts and acini. These primitive islets are solid structures, surrounded but not penetrated by capillaries. Mitoses were observed in A and B cells. In the following phase (tadpoles with hindlegs), D and pancreatic polypeptide-immunoreactive cells are also present, as well as numerous endocrine cells scattered among exocrine tissue. There is also a change in the vascular-insular pattern: capillaries not only surround but also penetrate the endocrine group. The structure of the endocrine pancreas in older tadpoles is similar. Tinctorial traits and ultrastructural features of endocrine cells are described, and the origin of primitive islets is discussed.
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