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Biomedical subjects

A Pollak

Publications and source records attributed to A Pollak.

At least 199 records · Page 11Linked to original sources
PubMed1982

[Diagnosis, treatment and follow-up of a patient with pseudohypoaldosteronism (author's transl)].

We report about a girl, 22 months old, with pseudohypoaldosteronism. The clinical course was characterized mainly by renal salt loosing syndrome, complicated by suddenly occurring hyperkalemic phases and a complete inability of renal electrolyte and acid-base regulation. Congenital adrenal hyperplasia was excluded and the diagnosis based on renal salt wasting despite hyperaldosteronaemia and increased plasma renin activity. Diagnosis and therapy of pseudo-hypoaldosteronism are discussed as well as the problems of long-term oral sodium chloride substitution and long-term therapy with sodium-polystyrol-sulfonate, a cation-exchange resin.

Acid-Base Equilibrium↗
PubMed1982

[Enzyme activities of native non-enzymatically glucosylated trypsin, chymotrypsin and papain].

The proteases trypsin, alpha-chymotrypsin and papain were incubated with glucose for a period of 10 days at 37 degrees C and activity was tested in comparison to the enzymes incubated with the puffer solution only without glucose addition. Papain additionally was incubated for 10 days at 37 degrees C with the carbohydrates galactose, sucrose, lactose, glucosamine, galactosamine and mannosamine. While trypsin and chymotrypsin showed no change in enzymatic activity after incubation with glucose, the activity of papain was reduced by 70% to 90% (mean 84%). Incubation with galactose also inhibited papain activity but to a lesser extent (25% to 60%, mean 43%). Incubation with the other carbohydrates failed to inhibit papain activity. The mechanism inferred is nonenzymatic glucosylation of papain possibly as ketoamine linkage at the lysine residues situated close to the active site of papain causing steric or allosteric hindrance of the papain activity. The serine hydrolases trypsin and chymotrypsin without lysine residues near their active sites revealed unchanged activity after incubation with glucose.

Carbohydrate Metabolism↗
PubMed1982

[Non-enzymatic glucosylation of proteins].

The modification of haemoglobin A by glucose to haemoglobin A Ic is a classical example for a nonenzymatic glucosylation (n. e. glu.) reaction of a protein. It has been suggested, that various proteins are subjected to this process during hyperglycemia phases, if the protein meets certain steric, electrostatic and biochemical characteristics. In the present report n. e. glu. of haemoglobin, serum protein, collagen, basement membrane protein and alkaline phosphatase is discussed. It is suggested that n. e. glu. might influence protein function and forms thus the biochemical basis for specific complications of diabetes mellitus in an outside pregnancy.

Adolescent↗
PubMed1981

Pulsatile secretion of gonadotropins in early infancy.

In adults, luteinizing hormone (LH) and follicle stimulating hormone (FSH) are secreted in a pulsatile manner. Prior to puberty gonadotropin (GN) levels are low and show only small fluctuations. The following investigation was performed to elucidate the type of GN secretion in infants. LH and FSH were determined every 30 min over a period of 8 h in three different groups: Group 1:2 male and 2 female adults; Groups 2:2 male and 2 female prepubertal children; Group 3:3 male and 3 female infants, aged 6-12 weeks. Group 1 showed a clear pulsatile secretion of LH (4.5-23.5 mIU/ml [range]) and FSH (6.9-16.0 mIU/ml). Group 2 demonstrated a rather constant secretion of LH (less than 1.5-2.3 mIU/ml) and FSH (1.6-4.9 mIU/ml). Group 3: In male infants pulsatile secretion of LH (3.6-34.7 mIU/ml)--and to a lesser degree of FSH (1.8-4.6 mIU/ml)--were found. In female infants the pulsatile secretion of FSH (6.5-22.7 mIU/ml) was more pronounced than that of LH (less than 1.5-4.7 mIU/ml). The secretory pattern in early infancy is of a pulsatile type.

Adult↗
PubMed1981

[Is the airway-occlusion-technique used in respiratory physiology hazardous for the newborn infant? (author's transl)].

The effect of the airway-occlusion-technique (AOT) on the cardiac- and respiratory frequency, respiratory compliance and pO2 was studied in 5 healthy and 7 cardio-respiratory ill newborns. During a mean study duration of 10.8 minutes (11 occlusions) none of the variables mentioned changed significantly. We conclude that the non-invasive AOT, which informs about lung mechanics and respiratory control, carries no risk for the newborn infant.

Elasticity↗
PubMed1981

Effect of tracheal suction on oxygenation, circulation, and lung mechanics in newborn infants.

Transcutaneous PO2, heart rate, and aortic blood pressure were measured i 10 mechanically-ventilated newborn infants to assess the degree and course of hypoxaemia, and to monitor the cardiovascular and respiratory changes during tracheal toilet. Five infants weighed less than 1250 (mean 994), g and 5 infants weighed greater than 1750 (mean 2216) g. During tracheal suction the TcPO2 fell from 68 +/- 27 (mean +/- SD) to 43 +/- 23 mmHg, and the heart rate from 144 +/- 8 to 123 +/- 25 beats/minute, but the blood pressure increased from 44 to +/- 24 to 49 +/- 24 mmHg. Hypoxaemia (TcPO2 less than 50 mmHg) occurred in 7 of 8 initially well-oxygenated infants when suctioned. The decrease in TcPO2 was similar for both groups of infants. It was greater in infants with controlled ventilation and an F1O2 greater than or equal to 0.8 than in infants with intermittent mandatory ventilation and an F1O2 less than 0.8. The TcPO2 fall correlated well with the TcPO2 during the control period but not during the time that the infants were disconnected from the respirator. A critical re-evaluation of routine tracheal toilet is needed.

Blood Pressure↗
PubMed1981

Argon laser photocoagulation of symptomatic flap tears and retinal breaks of fellow eyes.

A series of 95 eyes (93 patients) with retinal breaks, high-risk candidates for rhegmatogenous retinal detachment, were treated prophylactically with argon laser photocoagulation (ALP). Group A comprised 74 eyes with flap symptomatic tears. In 28 of these (subgroup A (1)) the size of the tear was smaller than 1 disc diameter and greater than 1/3 disc diameter. In 46 eyes (subgroup A (2)) the size of the tear was at least 1 disc diameter but not greater than 3 disc diameters. Group B comprised 21 fellow eyes with 34 retinal breaks in patients who had retinal detachment in the other eye. One patient of subgroup A (1) developed a rhegmatogenous retinal detachment 6 days after ALP treatment. One patient of group B developed a retinal detachment after cataract extraction. This detachment was unrelated to the previously treated retinal break. In the series of group A the mean follow-up period was 27.8 months. From previously reported follow-up data it is probable that at least in the case of flap symptomatic tears our results can be considered conclusive. There were no complications related to the prophylactic treatment of dangerous retinal breaks with ALP. This form of treatment is accurate, easy to use, and comfortable for the patient. ALP would appear to be superior to xenon arc photocoagulation and cryopexy.

Argon↗
PubMed1981

Total glycosylated hemoglobin in mothers of large-for-gestational-age infants: a postpartum test for undetected maternal diabetes?

Total glycosylated hemoglobin has been evaluated postpartum using a colorimetric (thiobarbituric acid: TBA) method in 50 mothers of large-for-gestational-age (LGA) infants (greater than 90th percentile by weight). 30 women without potential risk factors for chemical diabetes who gave birth to appropriate-for-gestational-age (AGA) infants formed the control group. When compared to the control mothers, mean total glycosylated hemoglobin (TBA color) levels were significantly higher in the mothers of LGA infants (p less than 0.01). 4 of the latter had an abnormal oral glucose tolerance test (GTT) done within 5 days postpartum and significantly elevated glycosylated hemoglobin compared to mothers of LGA infants with normal GTT (p less than 0.001). Furthermore, a significant linear correlation was found for mothers of LGA infants between TBA color levels and each of the following: fasting serum glucose (p less than 0.001), 1-hour serum glucose (p less than 0.001), 2-hour serum glucose (p less than 0.001), and infant birth weight (p less than 0.05). Analysis of TBA color levels early postpartum might be an alternative method for detecting unsuspected chemical diabetes in pregnancy.

Birth Weight↗
PubMed1981

[Serum ferritin in pregnancy at term and in newborn (author's transl)].

Serum ferritin, -iron, and -transferrin, and red cell blood count in 53 non-selected pregnant women at term, and from the respective cord blood samples were determined. In addition, serum ferritin was measured in 20 infants longitudinally on the first and sixth day of life. The mean cord blood concentrations of fetal serum ferritin were 135 micrograms/l, (maternal: 30,5 micrograms/l), and of fetal serum iron 27,7 mumol/l (maternal: 17,3 mumol/l), and of fetal transferrin 1,6 g/l (maternal: 4,43 g/l). A correlation between maternal and fetal serum ferritin levels could not be demonstrated. There was also no relationship between maternal serum ferritin concentrations and fetal serum iron, transferrin, and red blood count. Within the first week of life serum ferritin levels of the newborn showed a tendency to increase. From these results and from experimental data in the literature, we conclude that the feto-placental unit covers its demand on iron at the mother's expense, and independent from maternal iron stores. It is probably only an additional insufficient nutritional supply of iron, combined with depleted iron stores which might have unfavourable effects to the fetal and neonatal iron metabolism.

Erythrocyte Count↗
PubMed1980

Glomerular basement membrane changes, HbAIc and urinary excretion of acid glycosaminoglycans in children with diabetes mellitus.

Glomerular basement membrane antigens excreted into urine, urinary acid glycosaminoglycans and hemoglobin AIc plasma levels were estimated in 18 diabetic children. In comparison to controls we detected significant differences, in that diabetics with changed (alpha-1-) mobility on immunoelectrophoresis revealed increased urinary acid glycosaminoglycan excretion (p less than 0.01) and elevated HbAIc concentrations in plasma (p less than 0.01). HbAIc levels and urinary glycosaminoglycans correlated significantly (r = 0.7, p less than 0.001). Increased glycosaminoglycans as well as increased blood glucose reflected by elevated HbAIc could lead to the biochemical glomerular basement membrane changes found on immunoelectrophoresis. The results suggest a metabolic hypothesis for the development of diabetic glomerulopathy.

Adolescent↗
PubMed1980

[Intracellular concentration of phenylalanine, tyrosine and alpha-amino butyric acid in 13 homozygotes and 19 heterozygotes for phenylketonuria (PKU) compared with 26 normals (author's transl)].

Intracellular concentrations for phenylalanine, tyrosine, alpha-amino butyric acid and 7 other amino acids (glycine, alanine, valin, cystin, methionine, iso-leucin, leucin) were measured in lymphocytes of 13 homozygotes and 19 heterozygotes for phenylketonuria as well as in lymphocytes of 26 normals. Intracellular concentrations for phenylalanine, tyrosine and alpha-amino butyric acid were significantly higher in homo- and heterozygotes than in normals (p less than 0,001--p less than 0,01). For the other 7 amino acids there were no or only questionable differences. Between homo- and heterozygotes there was no difference in any of the amino acids. Intracellular phenylalanine: tyrosine ratio was essentially the same in all three groups of individuals. There was no correlation between intracellular phenylalanine above or below 10 nmol/10(6) cells and IQ in heterozygotes. The same is true for phenylalanine: tyrosine ratio greater or smaller than 1. In Homozygotes there was no correlation between intracellular phenylalanine and age -- to whom DQ/IQ is correlated. There was no significant difference in intracellular phenylalanine between homozygotes with blood levels above and below 908 mumol/l (15 mg/100 ml) at the time of blood sampling and no correlation between intra- and extra-cellular phenylalanine concentrations. Among the 26 normals there were only 2 with intracellular phenylalanine above 10 nmol/10(6) cells, both showing phenylalanine loading test curves suspicious for heterozygosity. The results are discussed and important functions of the cell wall supposed. An abnormal unknown intracellular metabolite being the real noxious agent could explain the incomparably different degree of brain dysfunction in individuals with equal though elevated intracellular phenylalanine concentrations i.e. homozygotes and heterozygotes for PKU.

Aminobutyrates↗
PubMed1980

Glycosylated hemoglobin (HbAtc) and plasma lipoproteins in juvenile onset diabetes mellitus.

Plasma lipid and lipoprotein levels and hemoglobin Atc estimates of diabetic control were measured in 19 juvenile-onset diabetics (8 girls and 11 boys) upon admission (day 1) and at the end (day 25) of a 4-week summer camp, where the patients were put on a controlled diet with a daily linoleic acid intake of about 16g. Lipoproteins were also measured in 64 healthy controls. When values on day 25 were compared with those of day one, a slight but significant decrease in mean hemoglobin Atc (10.4 +/- 0.3 vs. 9.8 +/- 0.4% of total Hb; M +/- S.E.M.; p < 0.05) was noted, as well as in increase in mean high density lipoprotein cholesterol (1.0 +/- 0.07 vs. 1.3 +/- 0.1 mmol/l; M +/- S.E.M.; p < 0.02) and a decrease in mean triglycerides (1.2 +/- 0.1 vs. 0.7 +/- 0.04 mmol/l; M +/- S.E.M.; p < 0.001). A linear correlation was found between hemoglobin AIc on day 25 and urine glucose excretion during the camping period (p < 0.01). However, no relationship was noted between hemoglobin AIc and either lipids or lipoproteins. Other factors, e.g. the controlled intake of saturated fat or physical activity could have responsible for the changes in triglycerides and high-density lipoprotein cholesterol levels noted by the end of the camp.

Child↗
PubMed1980

Reduced susceptibility of nonenzymatically glucosylated glomerular basement membrane to proteases: is thickening of diabetic glomerular basement membranes due to reduced proteolytic degradation?

Glomerular basement membrane (GBM) preparations were enzymatically glucosylated and applied to proteolytic degradation by several enzymes. The split products were then characterized and quantitatively estimated by high pressure liquid chromatography. For this purpose, GBMs were isolated by a sieving and sonication method, incubated with glucose and digested with the proteases trypsin, chymotrypsin, papain, pepsin and a lysosomal preparation. Comparison of the concentrations of split products obtained by proteolytic degradation of normal and nonenzymatically glucosylated membranes showed a remarkable reduced susceptibility of the nonenzymatically glucosylated membranes, possibly due to steric hindrance or altered electrical charge of the glucosylated membrane proteins. This could be interpreted as an additional factor for accumulation of basement membrane material in the diabetic state, that not only increased basement membrane synthesis may occur but also reduced catabolism could possibly contribute to the diabetic changes.

Animals↗