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Biomedical subjects

A Pollak

Publications and source records attributed to A Pollak.

At least 217 records · Page 12Linked to original sources
PubMed1980

Proteolytic degradation of the glomerular basement membrane and immunochemical characterization of split products.

Glomerular basement membranes (GBM) were isolated and subjected to enzymatic degradation with the protease trypsin (Serva), chymotrypsin (Serva), papain (Sigma), pepsin (Serva) and collagenase (Worthington) as well as a lysosomal preparation from glass adherent rat blood and peritoneal exudate cells. Split products were characterized by immunoelectrophoresis and cellulose acetate electrophoresis. Urine was obtained from healthy rats and rats with Masugi's experimental glomerulonephritis, dialyzed and concentrated and applied on immunoelectrophoresis, using anti-GBM antibody from rabbit. Urinary GBM split products from healthy and nephrotic rats showed two precipitation lines like digestion products obtained after chymotrypsin degradation. This finding was supported by characterizing individual antigenic degradation products obtained after inhibition of GBM degradation by the lysosomal preparation with ethylenediaminetetraacetic acid and Trasylol alone and in combination, as well as with o-phenanthrolin. It is concluded that GBM-antigens excreted into urine indicate limited digestion of GBM by chymotrypsin-type protease.

Animals↗
PubMed1980

Diurnal variation of circulating human myeloid progenitor cells.

We investigated whether human circulating myeloid progenitor cells (CFU(c)) exhibit diurnal variation. Peripheral venous blood samples were drawn every 3 h from each of the nine healthy male volunteers. Blood mononuclear cells were harvested by the Ficoll-Hypaque method. CFU(c) content of blood was determined by the soft agar cloning assay. Human placental conditioned medium (HPCM) was used as colony stimulating factor. We found a 24 h cyclic variation of colonies/10(5) mononuclear cells plated with a maximum at 9 a.m. (P < 0.01). Analysis of the colonies by in situ staining indicated that this variation could be attributed almost entirely to colonies composed of eosinophilic cells (representative of CFU(eos)). Neutrophil/macrophage colonies (representative of CFU(G,M)) exhibited a trend toward a 9 a.m. maximum, but this variation was not statistically significant. We conclude that time of blood collection should be standardized in experiments measuring human peripheral blood CFU(c).

Cells, Cultured↗
PubMed1980

Evidence of H2 receptor activity on glomerular cells.

The role of histamine in physiological and pathological states has not been fully elucidated. In the pathological state histamine release can be induced by several mechanisms. The most frequent events are IgE-mediated release, complement-mediated release and release by chemical agents. During inflammation histamine is set free and contributes to the course of inflammatory processes, either enhancing or inhibiting inflammatory reactions. In order to look for a target in the glomerulum we examined H2 receptor binding to isolated glomerular cells using 3H-cimetidine as ligand. Two binding sites were detected, a low affinity site with a kD = 6.3 microM and a high affinity site exhibiting a kD = 0.18 microM. These findings are comparable to properties of 3H-cimetidine receptor binding to brain membranes.

Animals↗
PubMed1979

[Haemoglobin AIc (HbAIc) and juvenile-onset diabetes].

HbAIc was determined in 20 children with juvenile-onset diabetes and in 15 healthy control children of a similar age group. HbAIc was 10.2 +/- 1.6% (mean +/- SD) of the total haemoglobin in the diabetic patients and 6.3 +/- 0.5% (mean +/- SD) in the controls. This difference was significant (P less than 0.001). A linear correlation was found between HbAIc and mean glucosuria over a 6-week period prior to HbAIc determination (p less than 0.01). It is concluded that HbAIc determination might be an important indicator of diabetic control and of the response to therapeutic measures since it represents an integrated gauge of blood glucose concentrations over several weeks.

Adolescent↗
PubMed1979

'Minor hemoglobins': an alternative approach for evaluating glucose control in pregnancy.

'Minor hemoglobins' (Hb AI) were measured in 178 women during pregnancy and immediately postpartum by a thiobarbituric acid spectrophotometric method. The patients were classified according to an oral glucose tolerance test (GTT) and an assessment of risk factors for diabetes in normal (n = 75), probably normal (n = 72) and chemical diabetics (n = 26). 5 pregnant insulin-dependent diabetics were also studied. Hb AI was unchanged during the second and third trimesters of pregnancy and immediately postpartum (less than 6 days) in women with normal glucose tolerance. Moreover, no difference of Hb AI level was found when compared with a separate group of nonpregnant individuals (n = 15). Chemical diabetics had significantly higher mean third trimester and postpartum Hb AI than normals (p less than 0.001). The highest Hb AI levels during pregnancy were found in the insulin-dependent diabetics, although these were lower compared to a separate group of nonpregnant insulin-dependent diabetics (n = 10; p less than 0.05). During pregnancy, a significant correlation was found between Hb AI and the 2-hour value of the GTT (p less than 0.001). A positive correlation was also found between third trimester maternal Hb AI and infant birth weight (p less than 0.001). Hb AI may complement other parameters in evaluating maternal glucose tolerance during pregnancy.

Birth Weight↗
PubMed1979

Phosphoenolpyruvate carboxykinase in experimental intrauterine growth retardation in rats.

This study examines the role of impaired gluconeogenesis in the pathogenesis of neonatal hypoglycemia in intrauterine growth retardation (IUGR). IUGR was produced experimentally in eight pregnant rats by ligation of uterine arteries at the 17th day of gestation. Delivery occurred spontaneously at term. Sham operations were performed in five pregnant rats at the same gestational age and the fetuses delivered at term served as controls. The body weights of newborn rats with IUGR were significantly lower than the controls (5.32 +/- 0.12 vs. 6.22 +/- 0.06 g, mean +/- SE, P less than 0.001). The fetal liver weights were also significantly smaller in IUGR than in the control animals (0.224 +/- 0.14 vs. 0.340 +/- 0.12 g, P less than 0.001). The activity of phosphoenolpyruvate carboxykinase (PEPCK) (the rate-limiting enzyme of gluconeogenesis) in liver cytosols was significantly lower in rats with IUGR (0.06 +/- 0.01 vs. 0.11 +/- 0.02 microM phosphoenolpyruvate/g liver/min when compared with controls (P less than 0.05). A direct relationship between this enzyme and the birth weight was observed, suggesting a close relationship between intrauterine nutrition and the status of gluconeogenesis. The blood glucose level was also lower in growth-retarted fetuses (36.6 +/- 4.7 vs. 69.6 +/- 4.3 mg/dl, p less than 0.001) when compared with controls. The data suggest that gluconeogenesis is impaired in IUGR and is partly responsible for the increase in the incidence of neonatal hypoglycemia in this group of subjects.

Animals↗
PubMed1979

[Verbal comprehension with objects and its comparison with the token test in children].

This study analyzes the results obtained in the child from an application of the Token Test of the De Renzi and Vignolo and compares them with those obtained from the application of a similar Test, in which objects of more familiar semantic field were employed. Normal children ranking from 4 years 0 month to 8 years 11 months were studied for this purpose.

Child↗
PubMed1978

The pharmacologic effects of furosemide therapy in the low-birth-weight infant.

The pharmacologic effects of furosemide were studied in six infants (mean gestation 30.7 weeks; mean birth weight 1,490 gm) at ages 10 to 57 days. Furosemide (for clinical indication, standardized at 1 mg/kg) was given intravenously over one minute; data were collected over the ensuing 24 hours. For three hours following furosemide administration, a significant diuresis was observed. Sodium excretion, percent fractional sodium excretion, and potassium excretion were significantly increased and urinary pH significantly decreased for six hours following the administration of furosemide. Creatinine and free water clearances were slightly elevated, although not significantly. Furosemide is an effective diuretic, the onset of pharmacologic action was within one hour, the peak action was sustained for three hours, and the duration of action was six hours. The net fluid, sodium, and potassium losses following a 1 mg/kg single dose were 28 ml, and 3.6 and 0.3 mEq/kg, respectively.

Furosemide↗
PubMed1978

[Maternal hemoglobin AIc (HbAIc) and diabetic pregnancy (author's transl)].

Third trimester HbAIc was determined in 57 pregnant women according to the TBA-reaction, first discribed by Flückiger and Winterhalter (1976). Simultaneously oral glucose tolerance tests (GTT) were performed in 52 patients; in 5 insulin dependent diabetic women dayly blood sugar profiles 2 to 5 times per week were done throughout the third trimester. HbAIc, when expressed as per cent of total hemoglobin, was 6.14 +/- 0.56% (m +/- SD) in women with normal GTT (n = 40) and found to be significantly (p less than 0,001) elevated in 7 women with abnormal GTT (7.54 +/- 0.61%; m +/- SD) and in the 5 women with insulin dependent diabetes (7.59 +/- 0.92%; m +/- SD). In patients with abnormal and boarderline GTT a linear relation between HbAIc and mean blood sugar, as determined from individually summarized 60 and 120 minutes GTT values, was observed. Insulin dependent diabetic women with higher mean blood sugar (as calculated from the total profile values throughout 4 weeks prior to HbAIc determination) showed a tendency towards higher HbAIc values.

Blood Glucose↗
PubMed1977

Fine structure of medulloepithelioma.

A survey of published cases of medulloepitheliomas indicates that this tumor is highly malignant (average course 6 months), occurs in early childhood (average age 4,4 years) and has no sex predilection. Although it may originate in any part of the central nervous system, it is most common in the cerebral hemispheres. The first case studied with the electron microscope is reported here. The fine structure of the tumor is similar to that of the fetal neural tube in showing a primitive epithelium having uniform nuclei rich in chromatin but little cytoplasm and sparse organelles; it rests on a distinct basement membrane. The epithelial surface lacks cilia or microvilli and is covered with an irregular amorphous coat which is probably the cause of the light-microscopic misinterpretation of an inner limiting membrane. The lateral cell surfaces lack interdigitations but show extensive primitive forms of cell junctions. The case presented is also unusual in being the second case on record originating in the cerebellum and the first showing massive seeding along the spinal canal.

Cell Membrane↗