Search PubMed⌕ Search

Biomedical subjects

J Koch-Weser

Publications and source records attributed to J Koch-Weser.

At least 37 records · Page 2Linked to original sources
PubMed1980

L-Ornithine decarboxylase:an essential role in early mammalian embryogenesis.

The highly selective, enzyme-activated, irreversible inhibitor of L-ornithine decarboxylase, DL-alpha-difluoromethylornithine, suppresses the increase in uterine L-ornithine decarboxylase activity associated with early embryogenesis in the mouse and arrests embryonic development at that stage. Contragestational effects were confirmed in the rat and rabbit. An increase in L-ornithine decarboxylase activity that leads to a rapid increase in putrescine concentration appears to be essential during a critical period after implantation for continued mammalian embryonal growth.

Adenosylmethionine Decarboxylase↗
PubMed1980

Depression of sympathetic nervous function by DL-alpha-monofluoromethyldopa, an enzyme-activated, irreversible inhibitor of L-aromatic amino acid decarboxylase.

We investigated the effects on peripheral sympathetic nervous function of monofluoromethyldopa (MFMD, RMI 71963), a selective, enzyme-activated, irreversible inhibitor of L-aromatic amino acid decarboxylase. Three daily injections of 2.5, 25, or 100 mg/kg MFMD to rats reduced the dopamine and norepinephrine concentrations in the heart and increased those of L-dopa. Sedation was seen with the two highest doses of MFMD. Cardiovascular responses in the pithed rat to stimulation of the whole spinal sympathetic outflow and to injections of tyramine were reduced by treatment with MFMD. Both the reduced sympathetic function and the depleted transmitter store were restored by infusions of dopamine. Norepinephrine depletion and functional inhibition were obtained with smaller doses of MFMD (3, 6, and 10 mg/kg daily) given for longer periods (10 days). Blood pressure in spontaneously hypertensive rats was reduced by treatment with MFMD, 25 mg/kg, daily for 3 days. In vitro responses to nerve stimulation of portal veins declined during incubation with MFMD or alpha-methyl-p-tyrosine; responses of atria were unaffected. Changes in norepinephrine concentrations of portal veins and atria closely paralleled the changes in function. MFMD is the first compound which depletes peripheral norepinephrine concentrations by inhibiting transmitter biosynthesis at the decarboxylase step. Such depletion results in inhibition of sympathetic function in vivo and introduces a novel approach to pharmacological manipulation of the activity of the peripheral sympathetic nervous system.

Animals↗
PubMed1980

Further studies on the inhibition of monoamine synthesis by monofluoromethyldopa.

1 alpha-Monofluoromethyldopa (MFMD, RMI 71963), a potent and selective enzyme-activated irreversible inhibitor of aromatic L-amino acid decarboxylase produces a substantial and long-lasting decrease in the catecholamine content of mouse brain, heart and kidney. 2 Single doses of MFMD reduce the 5-hydroxytryptamine concentration of mouse brain without altering the tryptophan concentration. 3 In animals treated with MFMD, peripheral but not brain noradrenaline is restored within 1 h to control levels by an intraperitoneal injection of dopamine.

Animals↗
PubMed1979

Effects of alpha-difluoromethylornithine, an enzyme-activated irreversible inhibitor or ornithine decarboxylase, on testosterone-induced regeneration of prostate and seminal vesicle in castrated rats.

1. Castration of adult rats markedly decreases the amounts of polyamines (putrescine, spermidine and spermine) and of RNA and DNA in the ventral prostate and the seminal vesicle. 2. Daily injections of testosterone propionate to rats castrated 7 days previously increase polyamine and nucleic acid contents more rapidly in the seminal vesicle than in the ventral prostate. 3. After 7 days of androgen treatment, polyamine and nucleic acid contents of the seminal vesicle are significantly higher than those of intact animals. Nucleic acid, but not polyamine, contents return to normal values during the next 4 days of continued treatment. In the prostate, androgen treatment increases polyamine and nucleic acid contents to, but not above, normal values. 4. Repeated doses of alpha-difluoromethylornithine, a potent enzyme-activated irreversible inhibitor of ornithine decarboxylase, totally blocked the testosterone-induced increase of putrescine and spermidine in the ventral prostate and of putrescine in the seminal vesicle. They slowed significantly the accumulation of spermine in the ventral prostate and of spermidine in the seminal vesicle. alpha-Difluoromethylornithine also retarded the testosterone-induced accumulation of RNA in the ventral prostate. However, no clear correlation was apparent between accumulation of polyamines and of nucleic acids in the two organs. 5. alpha-Difluoromethylornithine markedly slows the testosterone-induced weight gain of the prostate, but not of the seminal vesicle. Cytological studies suggest that this effect on the prostate is due to inhibition of the androgen-induced restoration of the secretion content of prostatic acini.

Animals↗
PubMed1979

Disopyramide.

Explore the source record for details and available documents.

Anti-Arrhythmia Agents↗
PubMed1978

Effects of terfenadine and diphenhydramine alone or in combination with diazepam or alcohol on psychomotor performance and subjective feelings.

The effects of single oral doses of terfenadine, diphenhydramine and placebo, alone or in combination with diazepam or alcohol, on psychomotor performance and subjective feelings were evaluated in a double-blind, crossover study in 20 normal male volunteers. Terfenadine 60, 120 and 240 mg had no effect on psychomotor skills and subjective feelings, whereas diphenhydramine 100 mg slightly impaired certain features of psychomotor performance and severely worsened subjective feelings. Terfenadine 120 mg did not influence the adverse effects of oral diazepam 10 mg or of alcohol 0.75 g/kg on psychomotor performance and subjective feelings. In contrast, diphenhydramine 100 mg significantly enhanced these effects of diazepam and alcohol.

Adult↗