Search PubMed⌕ Search

Biomedical subjects

M Frank

Publications and source records attributed to M Frank.

At least 217 records · Page 12Linked to original sources
PubMed1983

Studies on the mechanism of bacterial resistance to complement-mediated killing. III. C5b-9 deposits stably on rough and type 7 S. pneumoniae without causing bacterial killing.

Gram-positive cocci resist direct killing by serum. The mechanism of resistance was studied by measuring consumption of terminal complement components from serum and uptake of purified, radiolabeled C7 and C9 on rough and encapsulated type 7 Streptococcus pneumoniae. Extensive consumption of C5, C7, and C9 occurred when 5 X 10(8) rough or type 7 pneumococci were incubated for 1 hr in 10% pooled normal human serum (PNHS). Approximately 10,000 molecules of C7 and C9 bound per organism during the same period of incubation. Twenty to 30% of C7 and C9 was released from rough organisms. Release was not due to autolysis since it occurred with glutaraldehyde-fixed organisms as well as in S. pneumoniae that were rendered resistant to autolysis by growth in ethanolamine. Between 10 and 30% of bound 125IC9 counts were eluted from the rough and type 7 organisms by incubation in 1 M NaCl or 0.01 M EDTA, which suggests that bound C5b-9 was not attached by predominantly ionic interactions. Elution of 44 to 74% of 125IC9 from live and glutaraldehyde-fixed organisms by 1% sodium deoxycholate suggests that hydrophobic bonds are involved in C5b-9 attachment. Trypsin cleaved 67 and 55% of 125IC9 counts from live rough and type 7 S. pneumoniae, respectively which indicates that the bound complex is not protected by the cell wall from proteolytic attack. Serum resistance in S. pneumoniae does not represent a failure to form C5b-9 on the bacterial cell wall but apparently reflects a failure of the bound complex to penetrate the thick peptidoglycan layer.

Blood Bactericidal Activity↗
PubMed1982

Scanning electron microscopy studies of the vascular pole of the rat glomerulus.

The vascular poles of 30 renal corpuscles were studied in critical-point dried renal cortex of the Munich-Wistar rat by scanning electron microscope (SEM). In 28 cases one afferent and one efferent arteriole were observed; one was done in the Sprague-Dawley rat, where 34 renal corpuscles were examined. One afferent and a single efferent arteriole were found in 32 cases; in one case only one afferent and two efferent arterioles were observed. In another case it was questioned whether a single or a double efferent arteriole is present. In addition, the specimens allowed an evaluation of the area where the extraglomerular mesangium passes into the mesangial cells of the glomerular tuft. This area was found to be rather small to represent a "punctum fixum" for a contraction of the entire mesangium.

Animals↗
PubMed1982

A reliable preparation of mon-dispersed chromosome suspensions for flow cytometry.

A reproducible, simple and rapid protocol was developed to prepare mono-dispersed chromosome suspensions for flow cytometric analysis. The procedure basically employes: 1. twice rinsing of monolayer cultures to eliminate dead cells and cellular debris, 2. mild fixation of mitotic cells with 1% acetic acid, and 3. ultra sonic treatment to release single metaphase chromosomes. The procedure takes less than 30 min. Isolated chromosomes are storable over months at 4 degrees C. Despite mild fixation many biochemical studies and experiments applied on such fixed chromosomes purified and enriched using electronic sorting are feasible: 1. gene and restriction mapping, 2. cloning of specific gene sequences, and 3. gene frequency analysis.

Animals↗
PubMed1982

Comparison of the cerebral function monitor and plasma concentrations of thiopentone and alphaxalone during total i.v. anaesthesia with repeated bolus doses of thiopentone and althesin.

Repeated bolus doses of thiopentone or Althesin were administered to 10 patients every 240 s while cerebral electrical activity was recorded with the Cerebral Function Monitor (CFM). Peripheral venous blood samples were collected at 60 and 225 s after each bolus dose for the measurement of plasma concentrations of the drugs. Significant correlations in the range r = 0.56-0.96 (P = 0.02-0.00001) between plasma thiopentone or alphaxalone concentrations and the upper and lower edges of the CFM trace were found. For the patients with relatively poor correlations, better correlations were obtained when 60- and 225-s sample were analysed separately.

Alfaxalone Alfadolone Mixture↗
PubMed1981

Hyperosmolar nonketotic diabetic coma.

The authors report the case of a 12-year-old boy with hyperosmolar nonketotic diabetic coma. Pathogenetic aspects and the HLA genotype are discussed. To reduce the hyperglycaemia, a continuous intravenous infusion of regular insulin at a low rate was used. The too rapidly infused sodium-bicarbonate overloaded tha body with sodium and caused intracellular sodium accumulation with edema. This could explain the disorientation after regaining consciousness. Much more important than the sodium-bicarbonate infusion is an accurate rehydration regimen.

Bicarbonates↗
PubMed1981

[True XX/XY hermaphrotide, HY antigen positive, without detectable testicular tissue. Observation from birth to the age of ten years (author's transl)].

A rare modification of true Hermaphroditism is demonstrated in a ten-year-old child we have observed since birth. The cytogenetic analysis revealed a XX/XY-mosaicism. Two kinds of origin are discussed: 1. an ovum with two nuclei was fertilized by two different sperm cells, 2. two heterosexual zygotes fused. -- We could not find tissue of the testes but confirmed the diagnosis of a hermaphroditism by the detection of the HY-antigen and by typical endocrinological findings. Two different cell populations found in erythrocytes and by GPT-isoenzymes indicated a chimerism. By knowledge of these findings, we could help the child to undergo a positive psychological and social development.

Biopsy↗
PubMed1981

Induction of complement receptor expression in cell lines derived from human undifferentiated lymphomas. II. Characterization of the induced complement receptors and demonstration of the simultaneous induction of EBV receptor.

We have studied the specificity of complement receptors induced by theophylline in 2 cell lines derived from undifferentiated lymphomas, one of Burkitt's type, and compared it to that of complement receptors in other cell types. Both C3b and C3d receptors were induced. The induced C3b receptor differed from the C3b receptor of mature normal lymphocytes, polymorphonuclear leukocytes and the cells of a nodular lymphoma in 2 respects. Firstly, it bound C3b much less avidly (by a factor of several hundred-fold) and secondly, we were unable to demonstrate C4b binding. EBV receptors were induced at the same time as complement receptors, and permitted the conversion of a greater fraction of cells to EBNA positivity after experimental infection with EBV. The induction of receptors was not associated with a change in the fluidity of the plasma membranes and our data do not favor a different orientation of induced receptors within the membrane as compared to receptors of other cell types--a potential explanation for the different specificities. Our findings are consistent with the possibility that the complement receptors of lymphocyte precursors differ from these of mature lymphocytes.

Binding, Competitive↗
PubMed1980

[Recommendations for therapy of juvenile thalassemia major].

Haemosiderosis is the most common cause of death in patients with thalassaemia major because of haemolysis and the necessary repeated transfusions. It is possible to reduce the lethal iron burden by means of iron-chelating agents. We combine a two-day-high-transfusion-regimen of packed cells with the application of high doses of desferrioxamine (500 mg/kg body weight) intravenously. This way we achieve good iron elimination with minimal psychological stress situations.

Ascorbic Acid↗