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1

Digitale Medien

Perturbation of the switch-on of transcriptase activity in intermediate subviral particles from reovirus (1982)

Borsa, J. ; Sargent, M. D. ; Ewing, D. D. ; [weitere]

New York, NY [u.a.] : Wiley-Blackwell

Journal of Cellular Physiology 112 (1982), S. 10-18

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ISSN: 0021-9541

Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Biologie , Medizin

Notizen: Intermediate subviral particles (ISVP) derived from reovirus represent a simple model system for the switch-on of transcriptase function. In such particles the endogenous transcriptase is present in a switched-off form, one step removed from the switched-on state. Switch-on of transcriptase function is an active process in this system and can be triggered by K+ ions. A variety of agents which affect gene expression in cells were tested for an effect on switch-on in ISVP. Marked effects on switch-on in ISVP were observed with a diverse group of test agents, including DMSO and other solvents, BUdR, TdR, caffeine, theophylline, and temperature. The correlation in response between ISVP and cells suggests that the ISVP system may be useful as a model for studying the biochemical mechanisms underlying the perturbative effects of such agents on gene expression in cells.

Zusätzliches Material: 14 Ill.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1002/jcp.1041120104

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2

Digitale Medien

Pharmacokinetics and relative bioavailability of heptabarbital and heptabarbital sodium after oral administration to man (1975)

Breimer, D. D. ; Boer, A. G.

Springer

European journal of clinical pharmacology 9 (1975), S. 169-178

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ISSN: 1432-1041

Schlagwort(e): Heptabarbital ; heptabarbital sodium ; pharmacokinetics ; plasma concentration ; single and multiple dose kinetics ; relative bioavailability ; urinary excretion

Quelle: Springer Online Journal Archives 1860-2000

Thema: Chemie und Pharmazie , Medizin

Notizen: Summary A method has been developed for the quantitative determination of heptabarbital [5-(1-cyclohepten-1-yl)-5-ethylbarbituric acid] in human plasma after administration of single therapeutic doses of the drug. It involves a single extraction step followed by gas chromatography with alkali flame ionization detection, and the results were linear in the concentration range 0.125 – 5.0 µg/ml plasma. The pharmacokinetics and relative bioavailability of heptabarbital and heptabarbital sodium were studied in a crossover design in 7 healthy volunteers after oral administration of 20 tablets containing 200 mg heptabarbital and hard gelatine capsules containing an equivalent amount of its sodium salt. Heptabarbital concentrations in plasma were determined at regular intervals. The absorption of heptabarbital from the tablets was quite slow and peak level times varied from 1.5 to 4 h. The sodium salt was absorbed more rapidly and peak concentrations occurred between 1/3 and 2 h. In all cases the elimination of heptabarbital could be described by a single first-order process with an average half-life of 7.6 h (range 6.1 – 11.2 h). The half-life of the drug in each individual was about the same in the two trials. The relative bioavailability in each volunteer was estimated by comparing the areas under the plasma concentration curves. The sodium salt had an average bioavailability of 83% relative to the free acid. In some volunteers urinary excretion of unchanged heptabarbital was measured; cumulative excretion amounted to 0.16 – 0.30% of the administered dose. Four volunteers received one tablet each night for eight or ten days, but no accumulation was found. In three volunteers the half-life of the drug prior to and after these experiments did not change, whereas in the other volunteer the half-life decreased from 7.1 to 4.6 h. The possibility of enzyme induction should be considered when heptabarbital is taken regularly. It was concluded that heptabarbital was a suitable drug for the treatment of insomnia, since its half-life was rather short. Heptabarbital sodium may be used for induction of sleep, whereas Medomin® tablets, i.e. heptabarbital free acid, may be prescribed when the maintenance of sleep is the primary reason for treatment with a hypnotic drug.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/BF00614014

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3

Digitale Medien

The pharmacokinetics and metabolism of the anilide local anaesthetics in neonates (1978)

Moore, R. G. ; Thomas, J. ; Triggs, E. J. ; [weitere]

Springer

European journal of clinical pharmacology 14 (1978), S. 203-212

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ISSN: 1432-1041

Schlagwort(e): Mepivacaine ; pharmacokinetics ; neonates ; healthy adults ; metabolism ; renal excretion ; lignocaine

Quelle: Springer Online Journal Archives 1860-2000

Thema: Chemie und Pharmazie , Medizin

Notizen: Summary The pharmacokinetics and metabolism of mepivacaine has been studied in premature neonates dosed subcutaneously and in healthy adults dosed intravenously. The pharmacokinetics of mepivacaine in four neonates (N) was compared with that in six adults (A). Newborns had a significantly longer terminal phase half-life than adults (N mean 8.69 h; A mean 3.17 h). Total plasma clearance normalized on body weight was significantly smaller in neonates (mean 2.34 ml/min/kg) than in adults (mean 5.47 ml/min/kg), as was the hepatic blood clearance (N mean 1.37 ml/min/kg; A mean 5.10 ml/min/kg). The renal plasma clearance, however, was significantly greater in neonates (mean 0.76 ml/min/kg) than adults (mean 0.20 ml/min/kg). There was an average six-fold increase in the fraction of the dose excreted unchanged in newborns (mean 43.3%) compared to adults (mean 7.1%) with acidified urine (pH 5.5–6.0). There was significantly more of the mono-N-demethylated metabolite of mepivacaine excreted by newborns (mean 11.4%) than by adults (mean 2.2%), but their capacity to carry out aromatic hydroxylation of mepivacaine was negligible. These results for mepivacaine were compared with those previously reported for lignocaine in premature infants. The immaturity of hepatic function appears to have diminished more profoundly the ability of premature infants to metabolize mepivacaine than lignocaine. These findings are discussed in terms of perfusion theory of hepatic drug elimination.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/BF02089961

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4

Digitale Medien

Pharmacokinetics and metabolism of the anilide local anaesthetics in neonates. 11 etidocaine (1978)

Morgan, D. ; McQuillan, D. ; Thomas, J.

Springer

European journal of clinical pharmacology 13 (1978), S. 365-371

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ISSN: 1432-1041

Schlagwort(e): Etidocaine ; pharmacokinetics ; metabolism ; neonate

Quelle: Springer Online Journal Archives 1860-2000

Thema: Chemie und Pharmazie , Medizin

Notizen: Summary The urinary elimination of etidocaine and several of its metabolites was investigated in neonates whose mothers had received one or more doses of etidocaine during labour. The urine collection period ranged among the neonates from 21.4 to 47.0 h post-partum. The total amounts of etidocaine and its metabolites recovered in neonatal urine represented a mean of 0.12 per cent of the maternal dose. Some differences in the pattern of urinary metabolites were observed between neonates and adults. Mean half-life of elimination of etidocaine calculated from sigma-minus plots of the neonatal urinary data was 6.42 h. This is greater than that previously reported following intravenous administration of etidocaine to adults (2.6 h). The slower rate of elimination in neonates is probably due to an increased neonatal volume of distribution since there is evidence to show that etidocaine is extensively metabolised by the neonate.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/BF00644610

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5

Digitale Medien

The pharmacokinetics of diclofenac sodium in patients with active rheumatoid disease (1982)

Crook, P. R. ; Willis, J. V. ; Kendall, M. J. ; [weitere]

Springer

European journal of clinical pharmacology 21 (1982), S. 331-334

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ISSN: 1432-1041

Schlagwort(e): diclofenac sodium ; rheumatoid disease ; healthy subjects ; serum albumin ; pharmacokinetics

Quelle: Springer Online Journal Archives 1860-2000

Thema: Chemie und Pharmazie , Medizin

Notizen: Summary Pharmacokinetic data for diclofenac sodium has been well established in healthy volunteers, whereas in patients with rheumatoid arthritis very little information is available in the literature. A single oral dose of enteric-coated diclofenac sodium was given to 10 patients with active rheumatoid disease, adopting the same procedures used for a group of 10 healthy volunteers in whom pharmacokinetic data was already available. Plasma specimens were collected over a period of 8h following administration and concentrations of diclofenac determined by GLC. Resulting plasma concentration curves were similar to those obtained in the healthy subjects in that areas under curves and terminal half-lives were comparable. However, peak concentrations of diclofenac were significantly reduced in the rheumatoid patients. The lower peak concentrations were correlated with the lower serum albumin levels in the patients which are associated with active rheumatoid disease.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/BF00637622

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6

Digitale Medien

Studies of the different metabolic pathways of antipyrine in man (1982)

Danhof, M. ; Zuilen, A. ; Boeijinga, J. K. ; [weitere]

Springer

European journal of clinical pharmacology 21 (1982), S. 433-441

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ISSN: 1432-1041

Schlagwort(e): antipyrine ; antipyrine metabolites ; drug metabolism ; route of administration ; healthy volunteers ; urinary excretion ; pharmacokinetics

Quelle: Springer Online Journal Archives 1860-2000

Thema: Chemie und Pharmazie , Medizin

Notizen: Summary The pharmacokinetics of antipyrine in plasma and saliva, and urinary excretion of its major metabolites, were studied following i.v. and oral administration of antipyrine 500 mg to 6 healthy volunteers. Data from both plasma and saliva showed that the oral bioavailability of antipyrine given as an aqueous solution was complete. The saliva/plasma concentration ratio was constant with time from about 3 h onwards, with a mean value of 0.87 after oral and 0.91 after i.v. administration. It is concluded that the pharmacokinetic parameters of antipyrine can be satisfactorily established on the basis of salivary data, although the volume of distribution and clearance values are then slightly too high. After i.v. administration, 3.8±1.9% of the dose was excreted in urine as unchanged antipyrine in 48h, 24.9±6.3% as 4-hydroxyantipyrine, 16.5±3.2% as norantipyrine, 13.0±2.2% as 3-hydroxymethyl-antipyrine and 5.8±1.0% as 3-carboxy-antipyrine. No significant differences were observed following oral administration. The half-lives calculated from the linear part of the urinary excretion rate curves of the metabolites were about the same for oral and i.v. administration, and were of the same order of magnitude as the elimination half-life of parent drug in plasma and saliva. It is important for determination of the ultimate metabolite ratio that urine is collected for at least 36h, because there is a delay in the excretion of 3-hydroxymethyl-antipyrine in urine.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/BF00542332

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7

Digitale Medien

Pharmacokinetics and bioavailability of intravenous, oral, and rectal nitrazepam in humans (1982)

Jochemsen, R. ; Hogendoorn, J. J. H. ; Dingemanse, J. ; [weitere]

Springer

Journal of pharmacokinetics and pharmacodynamics 10 (1982), S. 231-245

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ISSN: 1573-8744

Schlagwort(e): nitrazepam ; i.v. ; oral ; rectal administration ; protein binding ; pharmacokinetics ; bioavailability

Quelle: Springer Online Journal Archives 1860-2000

Thema: Chemie und Pharmazie

Notizen: Abstract The pharmacokinetics and bioavailability of nitrazepam following intravenous, oral (tablet), and rectal (solution) administration were studied in seven healthy, young male volunteers. Nitrazepam plasma concentrations were determined by electron-capture GLC; pharmacokinetic evaluations were made by compartmental analysis (NONLIN) and compared with the results obtained by a less stringent modelling of the data. The plasma concentration-time profile was similar for all three routes of administration. Mean kinetic parameters as obtained by compartmental analysis of i.v. nitrazepam were: distribution half-life 17 min; volume of distribution after equilibrium 2.14 liters/kg; total plasma clearance 61.6 ml/min; elimination half-life 29.0 h. The mean protein unbound fraction of nitrazepam in plasma was 12.3% and the clearance of the unbound fraction was 506 ml/min. Absorption of oral nitrazepam started after the elapse of a lag time (mean value 12 min) and occurred as an apparent first-order process in all but one subject, with a mean absorption half-life of 16 min. Distribution and elimination half-lives were comparable with those following i.v. administration. Following rectal administration of the nitrazepam solution, rapid first-order absorption occurred with a mean lag time of 4 min and a mean absorption half-life of 9 min. Peak times (median 18 min) were significantly shorter than following oral administration (median 38 min), but there was little difference in peak concentrations. The distribution half-life was similar to i.v. and oral administration, but the elimination half-lives were longer with a mean value of 33.1 h. Following i.v. administration a good agreement was found between the results obtained by compartmental analysis using NONLIN and those obtained by a less stringent modelling of the data. Following oral and rectal administration, a good agreement between the two procedures was found for the elimination half-life; estimation of bioavailability, however, was higher by compartmental analysis. The mean bioavailability data showed that absorption is complete when nitrazepam is given orally and almost 20% lower when it is given rectally, but considerable interindividual differences were observed.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/BF01059259

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8

Digitale Medien

Setiferous structures of male coleoptera (1982)

Faustini, D. L. ; Halstead, D. G. H.

New York, NY : Wiley-Blackwell

Journal of Morphology 173 (1982), S. 43-72

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ISSN: 0362-2525

Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Biologie , Medizin

Notizen: A scanning electron microscopy study was made of the male setiferous sex patches and analogous structures in 11 families of Coleoptera (Anthribidae, Bruchidae, Ciidae, Cleridae, Coccinellidae, Dermestidae, Leiodidae, Ptinidae, Staphylinidae, Tenebrionidae, and Ostomatidae). These secondary sexual characters appear to have several features in common including relatively long, often ridged, setae, cuticular ducts (frequently cribriform pore plates), and the production of a secretion. It is suggested that these structures may all be concerned with the production, release, and dissemination of pheromones.

Zusätzliches Material: 21 Ill.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1002/jmor.1051730106

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9

Digitale Medien

Sorbic acid-induced differences in the ultrastructural development of oocytes in the microbially ectosymbiotic female of Xyleborus ferrugineus (fabr.) (coleoptera, scolytidae) (1982)

Chu, H. M. ; Norris, D. M. ; Rao, K. D. P.

New York, NY : Wiley-Blackwell

Journal of Morphology 173 (1982), S. 313-324

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ISSN: 0362-2525

Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Biologie , Medizin

Notizen: The ovaries of the beetle Xyleborus ferrugineus reared on standard sawdust diet with an without 0.08% sorbic acid added were examined for differences in ultrastructural development of the oocytes. Indications of vigorous yolk deposition are an extensive rough-surfaced endoplasmic reticulum (RER), numerous electron-dense secretory vesicles and a prominent nucleus in associated follice cells, and extremely electron-opaque material in the interfollicular cell spaces and the perioocytic area. After 6 days of feeding without added sorbic acid, a mature terminal oocyte is present in one of the two ovaries. This terminal oocyte at this mature stage contains yolk spheres and lipid bodies. However, the most mature oocyte in beetles reared on the standard sawdust diet to which 0.08% sorbic acid was added remained at a previtellogenic stage after 6 days of feeding. Titers of ecdysone in 6-day-old adult females reared on standard sawdust without and with 0.08% sorbic acid added were 534.64 ± 20.93 S.D. pg/mg and 39.94 ± 14.71 S.D. pg/mg body weight, respectively.

Zusätzliches Material: 8 Ill.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1002/jmor.1051730308

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10

Digitale Medien

The bursa cloacae (Fabricii) of struthioniforms in comparison with the bursa of other birds (1982)

Von Rautenfeld, D. Berens ; Budras, K.-D.

New York, NY : Wiley-Blackwell

Journal of Morphology 172 (1982), S. 123-138

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ISSN: 0362-2525

Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Biologie , Medizin

Notizen: The late embryonic and postembryonic genesis of the bursa cloacae (Fabricii) of struthioniforms and other birds is described and discussed. The bursa of ostrich and emu is a wall organ of the caudal cloacal chamber. The bursa of rhea is, like the bursa of Gallus, a cranial appendix of the proctodeum. Lobuli bursales of struthioniforms are composed of a peripheral pars lymphoepithelialis (PLE) and a central pars lymphoreticularis (PLR). By contrast, lobuli bursales of Gallus are composed of a peripheral PLR and a central PLE. The fine structure of the bursa of struthioniforms is described. Other than in Gallus, the apical cell association of the PLE of struthioniforms shows secretory granules. This study thus far does not answer in detail the question of how the imprinting mechanism of the B-lymphocytes operates. It is assumed that they are imprinted in the PLE. Postcapillary venules in the PLR are responsible for the transport of B-lymphocytes. Hormonal bursectomies have been made to get information about the involution of the bursa of struthioniforms. In these species, involution means a gradual metaplasia while in Gallus it means a complete degeneration of the bursa.

Zusätzliches Material: 16 Ill.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1002/jmor.1051720111

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