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Biomedical subjects

E Arnold

Publications and source records attributed to E Arnold.

At least 127 records · Page 7Linked to original sources
PubMed1985

Apparent inhibition of glycoprotein synthesis by S.cerevisiae mating pheromones.

Saccharomyces cerevisiae mating pheromones a and alpha factor strongly inhibit the incorporation of radiolabelled glucosamine into N-glycosylated proteins of corresponding haploid cells. This observation was erroneously interpreted as an inhibition of glycoprotein synthesis. It has turned out that alpha factor causes a 4-5-fold dilution of incorporated [14C]glucosamine with non-radioactive endogenous precursor. In the case of the [14C]chitin synthesized, which does not show inhibition by alpha factor, the lowering of the specific activity of the precursor is exactly compensated for by an increased rate of chitin synthesis caused by alpha factor.

Animals↗
PubMed1985

Effects of the rectal administration of diazepam. Diazepam concentrations in children undergoing general anaesthesia.

Diazepam 1 mg/kg body weight was administered rectally to 14 children (11-22.5 kg) before minor surgery under general anaesthesia. Administration in solution (n = 7) resulted in a rapid increase in serum concentrations which were maintained for 8 h. Administration by suppository (n = 7) resulted in significantly lower serum concentrations at 10 and 20 min, but higher concentrations at 2 h. At other intervals the concentrations did not differ from those reached after administration of diazepam in rectal solution. These results favour for use of a solution when rectal diazepam is used for premedication in children.

Anesthesia, General↗
PubMed1985

Single intravenous and oral doses of fenflumizole: pharmacokinetics and effects on prostanoid formation.

Fenflumizole is a substituted triaryl-imidazole with anti-inflammatory activity. Its disposition in man was studied after single intravenous and oral doses to 8 healthy male volunteers. Formation of the prostanoids thromboxane B2 (TXB2) and 6-keto-prostaglandin F1 alpha (6-k-PGF1 alpha) in clotting blood was studied concomitantly. The pharmacokinetics after intravenous doses (0.1 mg/kg) could be fitted to a three compartment model and the half-lives (t 1/2) corresponding to the three phases were 2 min., 1 hour and 15 hours, respectively. The volume of distribution was 386 l and the plasma clearance 0.5 l per min. Oral doses (0.5 mg/kg) were rapidly absorbed (t 1/2 = 0.2 hr) and the following elimination from plasma had two phases with half-lives of 1 hour and 14 hours. Bioavailability was 50% due to a pronounced first-pass effect. The two metabolites mono- and didemethylfenflumizole were detected after both oral and intravenous doses and their maximum plasma concentrations occurred after 1-2 hours irrespective of the administration route. A concentration dependent depression of prostanoid formation was seen, the IC50 for TXB2 and 6-k-PGF1 alpha being 19 and 53 ng/ml respectively.

6-Ketoprostaglandin F1 alpha↗
PubMed1985

Morphological and ultrastructural study of megakaryocytopoiesis in liquid cultures of hamster spleen.

A long-term liquid culture system of hemopoietic tissue derived from adult hamster spleen has been described. These primary liquid cultures can maintain stem cell proliferation and differentiation for more than three months without secondary repopulation. A characteristic of the liquid cultures is the formation of clusters of hemopoietic cells around adherent stromal cells. Some islands were composed exclusively of megakaryocytes and adherent cells. Isolation of these clusters of differentiating megakaryocytes and their adherent cellular substrate permitted the analysis of the morphological and ultrastructural features of the interaction between cells of megakaryocytic lineage with the adherent stroma.

Animals↗
PubMed1985

Absorption of metronidazole suppositories in patients with postoperative ileus.

Thirty-five patients with postoperative ileus were given one g metronidazole suppositories three times daily. The patients were divided into four groups according to the operative procedure. The postoperative bowel motility was assessed as the time at which bowel sounds and evacuation occurred. One group of patients differed significantly from the others with regard to the time taken for the bowel function to become normal. No significant difference existed in the serum concentrations of metronidazole between the groups. Absorption of the first suppository was slower in our patients than in normal subjects, but thereafter concentrations followed the theoretic concentration curve for healthy subjects on the same dose regimen. Steady state, indicating normal absorption, was attained before bowel function returned to normal. The reason for the slower absorption of the first suppository is probably that the patients were confined to bed.

Absorption↗
PubMed1984

Picornaviruses of two different genera have similar structures.

Crystals of Mengo virus were used to collect three-dimensional X-ray diffraction data to 7 A resolution. A self-rotation function showed the precise orientation of the Mengo particles in the crystal unit cell. A cross-rotation function against similar data of cubic rhinovirus crystals showed a peak when the orientations of these two icosahedral viruses were superimposed. This demonstrates similarity of capsid construction between two picornaviruses of different taxonomic genera.

Crystallization↗
PubMed1984

[Treatment of non-small cell bronchial cancer with high-dosage cisplatin and vindesine. Results of a prospective study].

Thirty-seven patients with advanced, histologically confirmed non-small-cell lung cancer received combination chemotherapy with high-dose (120 mg/m2, day 1 and 29, thereafter every 6 weeks) cisplatin and vindesine (3 mg/m2, day 1, 8, 15, 22, and 29, thereafter every two weeks). All patients had measurable disease and had not previously received chemotherapy. 20 out of 37 patients responded to therapy. Two patients with adenocarcinoma, and one patient with squamous carcinoma of the lung experienced complete remission, 11 out of 37 patients partial remission, three patients a minor response, while in three patients the tumour neither remitted nor progressed. Despite chemotherapy cancer progressed in 17 out of 37 patients. Under supportive care including prehydratation, diuresis, administration of high-dose metoclopramide this aggressive chemotherapy was well tolerated. The response rate was similar to that of other chemotherapeutic regimens. The remission duration (9.5 months) and the survival time (16.5 months) are, however, somewhat better.

Adenocarcinoma↗
PubMed1984

Virion orientation in cubic crystals of the human common cold virus HRV14.

A new cubic crystal form (a = 445.1 A) of space group P23 is reported for human rhinovirus R14. There are four particles per unit cell, each situated on a crystallographic 3-fold axis. The orientation of these particles has been determined with a rotation function and their approximate positions have been derived from a Patterson map. The crystals diffract to at least 2.8 A resolution. Limitations to the possible surface features of the virus are set by a comparison of the cubic and orthorhombic crystal forms.

Animals↗
PubMed1983

Predicting tenure decisions of psychiatric nursing assistants: individual and work-related factors.

Models were developed to predict the tenure status of 106 psychiatric nursing assistants at 3, 6, and 12 months after beginning employment at a large public psychiatric inpatient facility. The attrition rate of this sample was 40% which was consistent with trends reported in the literature. The predictive power of four groups of variables--personal, training, ward related, and organizational--was shown to change over time. Personal and training variables were significant early determinants of tenure, while ward and organizational factors gained more importance during the course of the year. Certain factors that appear important in reducing turnover of nursing assistants are discussed, with recommendations for program changes.

Adult↗
PubMed1983

Identification and distribution of megakaryocyte colonies in murine spleen.

This study is the first report on the utilization of specific cell function to identify splenic megakaryocytic colonies. Stem cell differentiation into megakaryocytes was studied by injecting each irradiated murine syngeneic recipient with 1 x 10(6) spleen cells. Morphological identification of erythroid, granulocytic, megakaryocytic, and mixed and undifferentiated colonies was done by staining consecutive cryostat sections with hemotoxylin and eosin, benzidine, myeloperoxidase, and acetylcholinesterase. The variation in the distribution of hemopoietic colonies within the spleen was reflected in the different ratio values derived for erythroid, granulocytic, and megakaryocytic colonies at varying depth within the spleen. An increase by 50% of megakaryocyte colonies was seen within the splenic pulp in the midzone region, compared with the surface. This suggests a localized microenvironment conducive for megakaryocytopoiesis. The data emphasizes the importance of identifying colonies of all cell types in histological sections of the spleen and evaluating spleen sections at least at two levels, one adjacent to the surface and the other in the midzone area.

Animals↗
PubMed1982

An obligatory role of protein glycosylation in the life cycle of yeast cells.

In the presence of 2-4 micrograms tunicamycin/ml, yeast cells stop growth after the cell number has increased 1.5-1.7-fold. The cells are arrested in G1: the rate of DNA synthesis greatly decreases and the budding index drops from 0.6 to 0.1 RNA synthesis is inhibited concomitantly, whereas protein synthesis is little affected. It is postulated that for G1/S phase transition to occur one or more proteins have to be glycosylated.

Cell Count↗
PubMed1982

The use of corporal punishment in child rearing in the West Indies.

The West Indian child is usually loved by its parents or caretakers, but is frequently subjected to corporal punishment unsuitable to the age and stage of its development and excessive in relation to the alleged offence. The debate on whether the persistent use of what is considered excessive punishment as the means of instilling obedience in children, centres around the parents' African heritage or learned behaviour from the institution of slavery. Socially and economically disadvantaged parents under stress seem to displace their frustrations and anxieties on the children through corporal punishment which often assumes ritualised characteristics. The community in general and the parents in particular need help through appropriate education, to change their attitudes of accepting excessive corporal punishment as the means of imposing discipline upon children.

Child↗
PubMed1982

The absorption and excretion of methyldopa ingested concomitantly with amino acids or food rich in protein.

Absorption and urinary excretion of 2-14C-L-alpha-methyldopa (alpha MD) were investigated in 5 healthy human volunteers. The drug was administered alone, with a mixture of amino acids and with a meal consisting of roast beef. The radioactivity in plasma and urine was not decreased significantly by either treatment, and it was concluded that the overall absorption of the drug was virtually unchanged. The amount of unconjugated alpha MD in plasma and urine, however, was significantly decreased following administration of the drug with roast beef. As the acid labile conjugates of alpha MD were practically unchanged an increased biotransformation to other metabolites owing to the protein rich meal was suggested more probable than competition between alpha MD and amino acids in the specific transport systems.

Adult↗
PubMed1982

Pharmacokinetics of intravenous metronidazole in man.

Metronidazole (500 mg) was infused over 20 min. to five patients. At the end of the infusion blood samples were drawn at brief intervals. After subsequent metronidazole analysis the curve plotted for the elimination of the drug showed a bi-exponential profile. Mean peak serum concentrations reached 15 micrograms per ml. At the end of the distribution phase, which was 20 to 30 min. after the infusion, the concentrations had fallen to 10 micrograms per ml. A two-compartment model was used to calculate the kinetic parameters. The elimination half-life ranged from 4.7 to 15.8 hours, the total clearance from 43 to 193 ml per min., and the peripheral distribution volume from 41.5 to 79.11 1. The areas under the serum level curves exhibited a four-fold variation, due to differences in either metabolism or elimination rate.

Adult↗
PubMed1982

In vitro proliferation of hematopoietic stem cells in the absence of an adherent monolayer.

Experiments on long-term murine bone marrow cultures indicate that the production and maintenance of the hematopoietic stem cell is dependent on the establishment of an adherent monolayer and a secondary repopulation of the culture with fresh marrow. In contrast, we have found that bone marrow cultures derived from the Syrian hamster do not require a repopulation step and produce stem cells that proliferate and differentiate for more than 12 wk in the absence of an adherent layer. Stem cells were grown in Fisher's medium (pH 7.0-7.2) containing 20% horse serum in a fully humidified atmosphere of 5% CO2 in air at 37 degrees C. Cultures were fed twice weekly by removal of half of the medium and supernatant cells and replacement with an equal volume of fresh medium. No hormones or exogenous growth factors were required for the maintenance of myeloid cells, monocytes, and megakaryocytes in either the adherent or suspension cells cultures.

Acetylcholinesterase↗