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Biomedical subjects

J Wagner

Publications and source records attributed to J Wagner.

At least 397 records · Page 22Linked to original sources
PubMed1984

Genetic evidence that chloroadenosine increases the specific activity of choline acetyltransferase in PC12 cells via modulation of an adenosine-dependent adenylate cyclase.

Both chloroadenosine (EC50 = 3 X 10(-7) M) and cholera toxin, like nerve growth factor, increase the specific activity of choline acetyltransferase in PC12 cells over a period of several days. The increase in choline acetyltransferase activity in response to chloroadenosine appears to be caused by the ability of chloroadenosine to increase adenosine 3':5'-phosphate synthesis by binding to an adenosine receptor that activates adenylate cyclase. To test this hypothesis we determined if chloroadenosine can cause an increase in choline acetyltransferase activity in adenosine kinase-deficient PC12 cells. We have previously shown that adenosine analogues are significantly less effective at regulating adenosine 3':5'-phosphate in adenosine kinase-deficient PC12 cells than in wild type cells [Erny and Wagner (1984) Proc. natn. Acad. Sci. U.S.A. 81, 4974-4978]. Adenosine kinase-deficient PC12 cells are resistant to the induction of choline acetyltransferase in response to chloroadenosine, but not cholera toxin, supporting the role of adenosine 3':5'-phosphate in mediating the effects of chloroadenosine. The increase in choline acetyltransferase activity in wild type cells was accompanied by an increase in acetylcholine levels, demonstrating that chloroadenosine also regulates storage of acetylcholine. Acetylcholine levels were quantitated using an assay based on the ability of acetylcholine to compete with [125I]bungarotoxin for binding to the acetylcholine receptor.

2-Chloroadenosine↗
PubMed1984

[Comparison of the electrocardiographic changes resulting from Urografin 76 and Iopamidol (Solutrast 370) during coronary angiography].

The electrocardiographic changes during, and immediately after, 410 injections in 50 patients were studied and related to the findings on coronary angiography and to the type of contrast medium used; the contrast media were Urografin 76 and the non-ionic Iopamidol 370. The results showed that 1.E.C.G. changes are much less marked if there is a stenosis of the coronary vessels. 2. Iopamidol 370 showed much less electrocardiographic change than was produced by Urografin 76.

Adult↗
PubMed1984

The metabolic fate of [14C]oxaprotiline.HCl in man. I. Disposition and preliminary pharmacokinetics.

Absorption, biotransformation and elimination of [14C]oxaprotiline.HCl have been studied after oral administration of 50 mg doses to two human subjects. Absorption was complete, and peak blood concn. of total 14C were 590 and 297 ng equiv./ml after 3-6 h in the two subjects. After 11 days, 84 and 90% dose was excreted in urine, and a total of 98% was excreted. Peak blood concn. of unchanged oxaprotiline were 16 and 19 ng/ml before, and 167 and 207 ng/ml after enzymic hydrolysis. The blood half-life in the two subjects was 23 and 29 h. The blood concn. of the desmethyl metabolite was low (2 ng equiv./ml), but also increased after hydrolysis (11-19 ng equiv./ml). Oxaprotiline was bound (83%) in vitro to serum proteins. Sixty per cent was bound to serum albumin and 20% to alpha 1-acid glycoprotein. In urine only 1% of total 14C was present as unchanged oxaprotiline, and 0.2% as the desmethyl metabolite. After enzymic hydrolysis these increased to 48 and 6%, respectively, and after acid hydrolysis to 85 and 10%.

Administration, Oral↗
PubMed1984

The effect of long-distance running upon appendicular bone mineral content.

The bone mineral content (BMC) of the os calcis was measured for a group of 20 male runners at the beginning and the end of a 9-month marathon training program. The participants had no previous running experience. The percent change in bone mineral in the runners was compared with that of a control group of male subjects of the same age range (38-68 yr). The consistent runners showed a significant increase in bone mineral over that of the controls; the increase was not significant for inconsistent runners. The data suggest that those runners with longer, more consistent distances gained more bone mineral than those with shorter, more inconsistent distances.

Adult↗
PubMed1983

[Septicemia. Etiology, epidemiology, clinical aspects and prognosis in 446 patients].

Between 1979 and 1982 446 patients with clinically and bacteriologically established septicaemia were ascertained in a prospective study in a university hospital complex with 1200 beds. This corresponded to an incidence of 8,4 cases of septicaemia in 1000 admissions. In 47.1% of patients the infection had been acquired as out-patient, 52.9% were hospital-acquired. 53.1% of patients were more than 60 years of age, 71.3% had predisposing underlying diseases or risk factors. Main signs of infection were increased temperatures of more than 38.5 degrees C (77.8%), anaemia and leukocytosis. The fairly equal distribution of gram-positive (207) and gram-negative (200) organisms was remarkable. The most frequently isolated bacterial species were E. coli (25.3%), Staph. aureus (21.8%), streptococci (11.1%), Staph. epidermidis (8.4%), enterococci (8.2%), and Klebsiellae (6.5%). 29.1% of patients succumbed. Nosocomial disease, liver cirrhosis, underlying malignant diseases, infections with Staph. aureus, enterococci, pneumococci, Pseudomonas aeruginosa and polymicrobial aetiology had an unfavourable prognostic influence. Thus, frequency and mortality of septicaemic diseases remain of unchanged considerable relevance in medical and surgical units. At present, aetiology and treatment will again have to consider gram-negative organisms to an increased extent.

Adult↗
PubMed1983

Comparison of 3-isobutyl-1-methylxanthine-induced accumulation of putrescine in rat pancreas and liver.

3-Isobutylmethylxanthine (IBMX), a potent phosphodiesterase inhibitor, causes accumulation of putrescine of same magnitude in rat pancreas and liver. IBMX produces increases of acetyl CoA: polyamine N'-acetyltransferase (PAT) and of ornithine decarboxylase (ODC) activities in both organs. However ODC activity is 300 times higher in liver than in pancreas. In the latter organ, there is a transient increase of N1-acetylspermidine, followed by a decrease of spermidine, alpha-Difluoromethylornithine (DFMO), a potent ODC inhibitor, impairs the accumulation of putrescine in liver but not in pancreas. These results suggest that in pancreas the accumulated putrescine is essentially formed from spermidine, via N1-acetylation and oxidation, while in liver it is formed from decarboxylation of ornithine. A possible involvement of cAMP in the stimulation of the polyamine interconversion pathway is discussed.

1-Methyl-3-isobutylxanthine↗
PubMed1983

Frequency limitation in the human baroreceptor reflex.

In 10 unsedated normotensive subjects, low-level bilateral electrical stimulation of the carotid sinus nerves (0.35 ms, 1-2 V) was applied with frequencies of 20-200 Hz for therapeutic purposes. Both peak and steady-state reflex effects increased with the stimulus rate up to 80 Hz. After 1 min of stimulation, the largest fall of arterial pressure (21.0 +/- 5.8%, mean +/- S.D.) was produced by stimulus frequencies of 80-120 Hz. Right atrial pacing did not modify the results. After 1 min of stimulation at 200 Hz, the arterial pressure fall was reduced to 13.6 +/- 5.2% (P less than 0.001), whereas peak effects, reached after 15-40 s, were near maximal. The reduction of the depressor response emerged after about 10 s of stimulation and was complete after about 1 min. Peak RR-interval prolongation occurred within 10 s and showed no adaptation. Comparison of continuous stimulation and R-wave-triggered intermittent stimulation in 3 subjects suggested that the reflex effect was determined by the mean stimulus frequency. We conclude that frequency limitation in the baroreceptor reflex begins when the stimulus rate exceeds about 80 Hz. It leads to a frequency-dependent, gradual adaptation of the reflex effects when the stimulus rate exceeds 120 Hz. This conclusion is limited to the part of the reflex that is subserved by myelinated afferent fibers.

Adult↗
PubMed1983

[Resistance spectrum of various bacteria against cefotiam in 3 Berlin clinics].

The in vitro activity of Cefotiam (Spizef) was tested using the agar diffusion test method according to DIN 58940 and compared with the antibacterial activity of 12 other routinely tested antibacterial chemotherapeutics. A total of 3000 strains from patients' specimens from the University Hospital of the Free University of Berlin and the Municipal Wenckebach Hospital, West Berlin, was tested. Cefotiam proved effective against strains of Staphylococcus aureus in 99,4%, Escherichia coli in 99,7%, Klebsiella species in 97,8%, Enterobacter species in 90,3%, Proteus mirabilis in 98,7%, indolpositive Proteus species in 91,7%, Citrobacter in 92,6%, and beta-hemolytic Streptococci in 99,3% of all strains tested. There were only few sensitive strains of Enterococci and of Pseudomonas aeruginosa.

Anti-Bacterial Agents↗
PubMed1983

[Spectrum of resistance of various bacteria against cefotiam in 3 Berlin clinics].

The in vitro activity of Cefotiam ( Spizef ) was tested using the agar diffusion test method according to DIN 58940 and compared with the antibacterial activity of 12 other routinely tested antibacterial chemotherapeutics. A total of 3000 strains from patients' specimens from the University Hospital of the Free University of Berlin and the Municipal Wenckebach Hospital, West Berlin, was tested. Cefotiam proved effective against strains of Staphylococcus aureus in 99,4%, Escherichia coli in 99,7%, Klebsiella species in 97,8%, Enterobacter species in 91,7%, Citrobacter in 92,6%, and beta-hemolytic Streptococci in 99,3% of all strains tested. There were only few sensitive strains of Enterococci and of Pseudomonas aeruginosa.

Berlin↗
PubMed1983

[High frequency pulsation (HFP) enabling tracheo-broncheal suctioning without interrupting mechanical ventilation].

A new technique of tracheo-broncheal suctioning is presented which enables constant artificial ventilation with high frequency pulsation (HFP), a modification of high frequency ventilation. Beyond that the high frequency pulsation method permits ventilation of the patient with adjusted end-expiratory pressure. This technique prevents the decrease of arterial oxygen pressure which is usually seen in patients who are disconnected for some time from the respirator as well as during the suction procedure and during periods of decreased end-expiratory pressures.

Blood Gas Analysis↗
PubMed1982

Aging of the erythrocyte. XIV. ATP content does decrease.

ATP content shows a cell-age dependent decrease in bovine erythrocytes separated according to Murphy. An important point in the evaluation of results lies in considering differences in the ATP consumption between cells of various age during separation. The decrease in ATP occurs in spite of diminished ATPase activity in older cells.

Adenosine Triphosphate↗
PubMed1982

Reversed-phase ion-pair liquid chromatographic procedure for the simultaneous analysis of S-adenosylmethionine, its metabolites and the natural polyamines.

A method using reversed-phase ion-pair liquid chromatography with dual detection was developed for the simultaneous determination of the S-adenosylmethionine (SAM) analogues and the natural polyamines. The separation is obtained with a gradient elution and by adjusting the concentration of octanesulfonic acid used as ion-pairing agent, the ionic strength of the eluent, the pH and the acetonitrile content of the eluents. The SAM analogues are analyzed by UV detection at 254 nm and the polyamines by fluorescence detection after post-column derivatization with o-phthalaldehyde. The method allows the determination of the SAM analogues and the polyamines in one single run by direct injection of tissue extracts. The procedure is applied to the study in rats and in hepatoma tissue culture cells of the biochemical effects of alpha difluoromethylornithine, a potent enzyme-activated irreversible inhibitor of ornithine decarboxylase.

Animals↗