摘要:

AbstractFoetal rat brain has previously been shown to contain twice as much mercury as maternal brain, after methyl mercury injection in the mother rat. However when brain mercury is corrected for the mercury which is present in the blood of the brain, foetal rat brain will contain 4 to 5 times as much mercury as maternal brain (depending on the stage of gestation), 24 hours after methyl mercuric chloride injection in the mother. Even when methyl mercuric chloride was injected in the mother about 14 days before term, near‐term foetal brain contains 1.4 times as much mercury as the maternal brain. Likewise when corrected for mercury in the blood of the organ, foetal rat liver contains from 2.0 to 2.6 times more mercury than the maternal liver, and the foetal kidney contains from 13 to 23 times less mercury than the maternal kidney. The amount of mercury in foetal blood is about 65 % of the mercury in maternal blood 24 hours after methyl mercuric chloride injection in the mother, but maternal and foetal blood contain equal amounts 14 days after the injection. Except for the foetal membranes, no inorganic mercury released by biotransformation of methyl mercuric chloride was detected in the foetal‐placental u

ISSN:0001-6683    

DOI:10.1111/j.1600-0773.1976.tb03123.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractHigh activities of acetylcholinesterase and choline acetyltransferase were found in the guinea‐pig retina compared to the brain, and in the cornea, iris and the external eye muscles compared to striated muscles. Instillation of diisopropyl phosphorofluoridate (DFP), sarin and paraoxon into the conjunctival sack was followed by rapid inactivation of the acetylcholinesterase in the cornea and iris, whereas the enzyme activity in the retina and the external eye muscles were much less affected. Thede novosynthesis of acetylcholinesterase in the iris and cornea was studied after irreversible inhibition of the enzyme by locally applied diisopropyl phosphorofluoridate following which 50 % of the enzyme activity returned to both regions after 7–10 days. Acetylcholinesterase inhibited by diisopropyl phosphorofluoridate, sarin or paraoxon could be reactivated by locally applied toxogonin or pyridine‐2‐aldoxime methyliodide. Benzalkonium in 0.03 % solution increased the degree of reactivation probably by increasing the permeability of the

ISSN:0001-6683    

DOI:10.1111/j.1600-0773.1976.tb03124.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractIn a cross‐over study on 6 healthy volunteers, the serum concentrations and the bioavailability of 16 oral phenoxymethylpenicillin preparations have been compared. The dissolution rates of the tablets and capsules were studied. The preparations included 5 aquous solutions, 7 tablets or capsules, and 4 suspensions. The highest bioavailability was seen with the aquous solutions and the tablets or capsules containing the potassium salt of phenoxymethylpenicillin. Two calcium salt tablet brands showed lower serum mean concentrations and bioavailability than the other, potassium salt, tablets and capsules, but the differences were only statistically significant for one of the calcium salt tablets as compared to the tablet with the highest mean concentrations. The poorer bioavailability of the calcium salt tablets was reflected in longer dissolution times. The suspensions intended for paediatric use were significantly inferior to most of the other preparations. The lowest bioavailability was observed with a suspension containing the poorly soluble benzathine phenoxymethylpenicilli

ISSN:0001-6683    

DOI:10.1111/j.1600-0773.1976.tb03125.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractThe uptake of14C‐neostigmine in the isolated diaphragm was studied after chronic treatment of rats with either neostigmine or diisopropyl fluorophosphate (DFP) and following chronic denervation of the left hemidiaphragm. The uptake was measured as muscle‐to‐medium14C‐concentration ratio after 3 hours incubation of hemidiaphragms with 3 × 10‐7M14C‐neostigmine. Subcutaneous injections of neostigmine 150 μg per day for 7 days or DFP 165 μg per day for 10 days to rats weighing 190–220 g resulted in a highly significant increase of14C‐neostigmine uptake in the isolated diaphragm. Chronic denervation did not affect the14C‐neostigmine uptake. The results demonstrate that chronic administration of anticholinesterases induce changes in the diaphragm, which result in an increased uptake of14C‐neostigmine

ISSN:0001-6683    

DOI:10.1111/j.1600-0773.1976.tb03126.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractThe mode of action of a calcium‐antagonistic drug, nifedipine, on the spontaneously beating, isolated, perfused rat heart was studied at two different calcium concentrations of the Ringer solution, [Ca++]o, (2.0 and 5.0 meq./l). The sinus node discharge, the aortic pressure amplitude and hence the work index were greater at 5.0 than at 2.0 meq./l. Nifedipine 100 μg/1 caused a reduction in these parameters, the effects being most pronounced at the lowest [Ca++]ostudied. ECG tracings demonstrated that the PR‐interval was longer at 2.0 than at 5.0 meq./l of calcium. The AV conduction time further increased after the addition of nifedipine. This effect was enhanced at the lowest [Ca++]oused, where varying degrees of AV block occurred in several experiments. The drug also reduced the R‐wave voltage and the RT‐interval. Calcium‐induced ventricular tachyarrhythmias were produced, which were suppressed by nifedipine. Nifedipine 100 μg/l produced a small and transient increase in the coronary flow, but a tremendous increase in the ratio coronary flow/work index was observed. This indicates improvement of the cardiac energy balance caused by an increase in the coronary oxygen supply in relation to the myocardial ox

ISSN:0001-6683    

DOI:10.1111/j.1600-0773.1976.tb03127.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractThe levels of d‐ and 1‐amphetamine in the brain and heart of adult and developing mice aged 3–6 days and 13–16 days were studied. More d‐ than 1‐isomer was found in the brain of developing mice, except after a dose of 100 mg/kg of the drug, i. e. a dose which produces a higher level of 1‐amphetamine in the brain of 13–16‐day‐old mice. Adult brain retained 1‐amphetamine in a higher concentration than d‐amphetamine. In the youngest mice 50 mg/kg of the isomers produced equal levels of the drug in the brain and heart, whereas 100 mg/kg of the d‐form was particularly concentrated in the infant heart. In the older age groups the brain level of either isomer was generally higher than the respective heart level. The age‐ and dose‐dependent differences in the distribution of amphetamine isomers emphasize the importance of peripheral component of amphetamine action in the youngest mice and reveal a low sensitivity of the central nervous system to 1‐amphetamine in 13–16

ISSN:0001-6683    

DOI:10.1111/j.1600-0773.1976.tb03128.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractThe levels of serum human growth hormone (HGH), immunoreactive insulin (IRI), blood glucose (BG), and plasma renin activity (PRA) in a total of 131 healthy voluntary medical students and in 83 control subjects were studied to find out whether the psychic stress of examination in pharmacology can affect the release of these hormones. The mean HGH level rose by 33 per cent after a written interim examination (P<0.05) and by 49 per cent (P<0.01) after a final oral examination. The mean IRI level rose by 45 per cent (P<0.01) after a written examination and by 43 per cent (P<0.01) after an oral examination. The mean BG level did not vary significantly. The rise in HGH and IRI was higher after short examination periods (<60 minutes) than after longer examinations (<90 minutes). The mean PRA rose by 44 per cent (P<0.05) after a written and by 27 per cent (P<0.05) after an oral examination, but the mean values of PRA after an examination were, however, within the normal range.

ISSN:0001-6683    

DOI:10.1111/j.1600-0773.1976.tb03129.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractThe degradation of Fast Red E, Amaranth, Ponceau 4R and Ponceau 6R in anaerobic incubates of rat caecal extract was studied by spectrophotometric scanning. The compounds underwent reduction of the azo linkage and thus loss of colour. The reaction rates seem to depend on the number rather than position of the sulphonate groups in the molecule.

ISSN:0001-6683    

DOI:10.1111/j.1600-0773.1976.tb03130.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractThe effects of clozapine on the accumulation and disappearance of14C‐labelled catecholamines formed from14C‐tyrosine, and on the endogenous levels of catecholamines have been studied in mouse brain. Rather low doses of clozapine increased noradrenaline accumulation and disappearance (from 2.5 and 0.16 mg/kg, respectively), whereas dopamine accumulation was only increased from 10 mg/kg and disappearance after 80 mg/kg. However, in the dosage interval of 1.25 to 5 mg/kg dopamine disappearance was decreased. Endogenous noradrenaline levels were decreased from 10 mg/kg in contrast to the dopamine levels which remained unchanged, except in the dosage interval 2.5 to 10 mg/kg, where they were elevated, at the same time at which dopamine disappearance was decreased. It is concluded that clozapine differs biochemically from the typical neuroleptics by changing the metabolism of noradrenaline in doses much lower than those influencing dopamine metabolism. It is suggested that this property together with the ability of clozapine to decrease dopamine disappearance in a certain dose range, could contribute to the unique psychopharmacological action of clozap

ISSN:0001-6683    

DOI:10.1111/j.1600-0773.1976.tb03131.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractThe liver acetaldehyde dehydrogenases and the acetaldehyde level in the blood during ethanol metabolism were studied in rats 24 hrs after the administration of disulfiram. High doses of disulfiram (150–600 mg/kg) caused a threefold decrease in the activity of the mitochondrial low‐Kmenzyme, whereas no significant effects were found on the activity of the high‐Kmenzymes present in the mitochondrial, the microsomal and the cytosolic fractions. The concentration of acetaldehyde was threefold higher in the hepatic venous blood and fivefold higher in the peripheral blood in rats given disulfiram compared to rats given ethanol only. Low doses of disulfiram (25–50 mg/kg) decreased the activity of the low‐Kmenzyme by 26 %, and caused a significant increase in the liver output of acetaldehyde. The rate of ethanol elimination decreased by 35 % at a high dose of disulfiram, whereas the alcohol dehydrogenase activity was not influenced. It is suggested that the mitochondrial low‐Kmenzyme has a primary role in the regulation of the hepatic output of acetaldehyde, and the results will be discussed with special reference to the site and kinetics of acetaldehyde oxidation during ethanol metabolism i

ISSN:0001-6683    

DOI:10.1111/j.1600-0773.1976.tb03132.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY