Search PubMed⌕ Search

Biomedical subjects

E Arnold

Publications and source records attributed to E Arnold.

At least 145 records · Page 8Linked to original sources
PubMed1982

Presence of mixed colony-forming cells in long-term hamster bone marrow suspension cultures: response to pokeweed spleen conditioned medium.

In contrast to the murine system, long-term hamster bone marrow suspension cultures maintain proliferation of both pluripotent and committed stem cells in the absence of an adherent layer and without addition of exogenous factors, such as hydrocortisone. Addition of pokeweed-mitogen-stimulated hamster spleen conditioned medium (SCM) to these long-term suspension cultures produces an increase in the number of mixed colonies assayed in soft-agar, These mixed colonies, which contained four cell lineages--granulocytic, erythroid, megakaryocytic, and macrophage--could be generated from cells grown in suspension for over 6 mo. Addition of SCM also induces an initial rapid expansion of the myeloid compartment, and this expansion results in 70% of the cells being terminally differentiated granulocytes. In contrast, addition of SCM to hamster bone marrow cultures containing both adherent cells and hematopoietic stem cells produced no change in the number of mixed colonies generated in the culture. This system allows the in vitro study of the process of stem cell proliferation and differentiation and also provides a means to examine the relationship of adherent and supernatant bone marrow populations.

Animals↗
PubMed1980

[Frequency of minimal pulmonary lesions as precursors of tuberculosis].

Numerous studies have referred to the degree of frequency with which so-called minimal pulmonary lesions are the starting-point for active pulmonary tuberculosis. In the present study, which takes the inverse approach, minimal lesions were searched for in medical records antedating the disease of patients treated for active tuberculosis. 343 case histories of pulmonary tuberculosis patients were scrutinized, representing 66% of declared cases among the reference population over a period of 7 years. After stringent selection, 78 case histories were retained as being likely to provide an answer to the question posed: minimal lesions were present in 41% of the cases prior to pulmonary tuberculosis. Although this is a high figure it is a minimum, since minimal lesions exist which are not reflected radiologically.

Humans↗
PubMed1980

Pharmacokinetics of metronidazole in healthy adult volunteers after tablets and suppositories.

A cross-over study on metronidazole was carried out with 10 healthy adult volunteers who received tablets (250, 500 and 1,000 mg) and suppositories (500, 1,000 and 2,000 mg). The bioavailability of the suppositories was approximately 90% of the corresponding tablet dose as judged by area under the serum curves and amounts excreted in urine. The absorption was faster after the tablets. The mean curve peaks of unchanged metronidazole after the tablets occurred within 1 h and were 3.7 microgram/ml after 250 mg, 9.8 microgram/ml after 500 mg, and 11.8 microgram/ml after 1,000 mg. The suppositories rendered peaks of 5.5, 9,5 and 14.0 microgram/ml 4 h after doses of 500, 1,000 and 2,000 mg, respectively. In the dosage range 250-1,000 mg, the relationship between the dose and the total area under serum curves was similar for tablets and suppositories. Parts of the drug in serum and urine were antibacterially active metabolites. The mean recovery in urine within 36 h was 7-14% of the dose. The serum half-life of unchanged metronidazole (chemical assay) was 8.8-10.5 h. The terminal phase half-life of the total biologically active compound (microbiological assay) was 7.8-15.1 h.

Adolescent↗
PubMed1980

Absorption and excretion of metronidazole after administration of metronidazole benzoate mixture.

Serum concentrations and urinary excretion of metronidazole after single dose therapy were investigated in patients with giardiasis. A metronidazole benzoate mixture was administered to 10 adults in total doses of 2 g and to 6 children in doses of approximately 50 mg/kg body weight. No unhydrolyzed metronidazole benzoate was found in the serum. The maximum serum concentrations of metronidazole averaged 30 microgram/ml. These values as well as estimated metronidazole absorption were approximately 30% lower than in 3 adult patients given single doses of 2 g of pure metronidazole in tablet form.

Adult↗
PubMed1980

Comparison of metronidazole assay by microbiological and chemical methods.

Chemical (thin layer chromatography/fluorescence quenching in situ) and microbiological (agar well, diffusion technique with Clostridium perfringens as indicator strain) methods of assaying metronidazole have been compared. On dummy samples made with pure metronidazole in pooled human serum, both methods had a coefficient of variation ranging from 5.5 to 9.6 per cent of the mean. The microbiological method slightly underestimated the real amounts, and also had lower values than the chemical procedure. Comparison of serum and urine samples taken during the early, middle and late periods after medication to volunteers showed that biotransformation to antibacterially active metabolites contributes significantly to the antibacterial activity, particularly in urine. Biotransformation explains why microbiologically determined concentrations were higher than those determined chemically in samples taken at least 16-20 hours after intake of tablets or suppositories. It is important to be aware of the circumstance that the results of microbiological assay are sensu strictu limited to the particular indicator strain used, since other bacteria may exhibit other patterns of sensitivity to metronidazole and its metabolites.

Biological Assay↗
PubMed1979

Absorption of diazepam in man following rectal and parenteral administration.

Serum concentrations of diazepam and N-desmethyldiazepam were measured in six adult patients following administration of 10 mg diazepam in solution by the rectal, intravenous, and intramuscular routes. Maximum serum concentrations of 121--200 ng/ml were recorded from 10 to 20 min. after the rectal instillation, whereas following intramuscular injection the levels rose slowly and irregularly, reaching a maximum (62--186 ng/ml) in 1 to 24 hours. The bioavailability of diazepam given by rectal instillation was found to be 50 +/- 17 per cent (mean +/- S. D.) as compared with the intravenous administration. The possible reasons for the low bioavailability are discussed. It is concluded that administration by rectal tube provides a useful alternative to the tablets (and intramuscular injections) when a rapid onset of effect of the drug is wanted, and when intravenous administration is not applicable or practical.

Absorption↗
PubMed1978

[Comparative investigations on polymorphism of the red cell enzymes in Franconia and West Hungary (author's transl)].

The distribution of the phenotypes of the red cell enzymes adenosine deaminase, adenylate kinase, glutamate pyruvate dehydrogenase, 6-phosphogluconate dehydrogenase and phosphoglucomutase was studied in blood samples of 794 West Hungarian subjects and 955 subjects from Franconia in Bavaria. All enzymes were separated on cellulose acetate foil, SEP in starch gel. The method of separation has been described elsewhere. The phenotypes of all enzymes were found to be distributed according to the Hardy-Weinberg law. The calculated gene frequencies were in good agreement with data from the literature, according to the results of other investigations carried out in Germany and the central European region. No significant difference was found between the gene frequencies of these enzyme phenotypes in West Hungary and Franconia, although the PGM2 frequency level was higher in West Hungary than in Franconia.

Acid Phosphatase↗
PubMed1978

Serum diazepam and serum creatine kinase after intra-muscular injection of diazepam in two different vehicles.

Serum diazepam concentration and serum creatine kinase activity (serum CK) were measured in 35 patients (who were divided into three groups (A, B, and C)), over a period of 24 hours after administration of diazepam. An increase in serum CK was regarded as an indication of local muscle injury. In group A, diazepam in a polyethyleneoxydricinolate vehicle was injected intramuscularly; in group B, diazepam in a propyleneglycol-ether alcohol vehicle was injected intramuscularly; and in group C, diazepam was administered orally, combined with intramuscular administration of the vehicle used in group B. The investigation was double-blind and randomized. Serum diazepam absorption expressed as the area under the concentration curve was identical in groups A and C and significantly higher than in group B. Serum CK rose in all groups. The differences among the groups were not significant. There were considerable individual variations in all three groups, and almost half the patients showed no increase in serum CK at all. No negative correlation was found between serum diazepam and serum CK. Thus no effect of muscle injury--if present--on absorption rate could be demonstrated.

Administration, Oral↗
PubMed1978

Alpha-methyldopa and drug fever. A study of the metabolism of alpha-methyldopa in patients and normal subjects.

The metabolism of alpha-methyldopa was studied in 5 patients with febrile reactions to the drug, and compared with the metabolism in 5 patients without such reactions and in 4 normal subjects. A depression of the drug metabolism was found in drug fever patients, which may affect either the intestinal mucosal conjugation of the drug or the hepatic transformation. The decreased metabolism is assumed to be a possible causative mechanism of the adverse reaction.

Adult↗
PubMed1977

Presence of histone mRNA sequences in high molecular weight RNA of HeLa cells.

Pulse-labeled HeLa cell RNA centrifuged under denaturing conditions was hybridized with DNA of recombinant phages containing sea urchin histone genes. This cross-hybridization showed the presence of histone mRNA sequences in high molecular weight RNA molecules. Treatment of the cells with actinomycin to stop RNA synthesis resulted in the rapid decay of this high molecular weight RNA followed by an increase of 9S histone mRNA in the cytoplasm. The results are consistent with the presence in HeLa cells of a high molecular weight precursor to histone messengers.

Coliphages↗
PubMed1977

Synthesis of histone messenger RNA of HeLa cells during the cell cycle.

Hybridization of HeLa cell RNA to the DNA of a recombinant phage containing sea urchin histone genes shows that histone mRNA of HeLa cells is synthesized throughout the entire cell cycle. Furthermore, histone messenger is synthesized in cells treated with cytosine arabinoside, an inhibitor of DNA duplication. Although histone RNA is found in the nucleus, the amount of cytoplasmic histone messenger is drastically reduced, in agreement with previous work. The absence of coupling between histone mRNA synthesis and DNA duplication shows that the regulatory process which determines the presence or absence of histone mRNA in the cytoplasm of HeLa cells is not at the transcriptional level.

Cell Cycle↗
PubMed1977

[Statistical investigations of nosological parameters (sex distribution, diagnosis, age of onset) in 120 pairs of endogenous psychotic parent-child and sibling relationships (author's transl)].

120 pairs of parent-child and sibling relationships with endogenous psychoses--registered through 60 schizophrenic and manic-depressive probands each--are statistically investigated with regard to the nosologically and biologically relevant parameters of sex distribution, diagnosis and age of onset.

Adolescent↗