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Biomedical subjects

A Pollak

Publications and source records attributed to A Pollak.

At least 163 records · Page 9Linked to original sources
PubMed1984

Explanation of the pseudohypoaldosteronism (PHA)-stress syndrome with an artificial aldosterone receptor model.

A receptor for aldosterone was studied in the cytosol of rectal mucosa of two sisters (M.A., M.B.) with the clinical manifestations of pseudohypoaldosteronism (PHA). Compared to age matched controls the patients showed a decreased affinity for aldosterone (M.A. Kd1: 0.18 nM, Kd2: 4.55 nM; Nmax1: 0.185 fmol/mg cytosol protein (CP), Nmax2: 3.12 fmol/mg CP, respectively). In an attempt to find an explanation for the phenomenon of stress-induced electrolyte imbalance in PHA patients an experimental set up was designed, using aldosterone antibody material as artificial aldosterone receptor. Specific binding was evaluated in addition with and without a 25-100-fold molar excess of dexamethasone (DEX) in order to overcome the glucocorticoid affinity of the aldosterone receptor, a phenomenon proposed to be the cause for the severe consequences of stress in some patients with PHA. The aldosterone antiserum showed two binding sites, similar to the natural receptor (Kd1: 0.15 nM, Kd2: 1.30 nM; Nmax: 30 fmol/mg CP and 130 fmol/mg CP, respectively). Under the influence of DEX the high affinity binding site (Kd1) was occupied by the glucocorticoidanalogon (Kd: 1.30 nM; Nmax: 125 fmol/mg CP). In conclusion, in stress situations, with increased quantities of glucocorticoid circulating, the high affinity binding site of the aldosterone receptor might be occupied by the glucocorticoids, while the low affinity binding site in PHA patients might not have sufficient binding capacity to maintain the electrolyte balance.

Adolescent↗
PubMed1984

Abnormalities of chromosome 16 in association with acute myelomonocytic leukemia and dysplastic bone marrow eosinophils.

Six patients with M4 acute myelomonocytic leukemia ( AMMoL ) were identified who had abnormalities of chromosome 16 in bone marrow cells. Five had a pericentric inversion, inv(16)( p13q22 ), and a sixth patient had a translocation, t(16;16)(p13.1;q22). Each of these six patients had bone marrow eosinophils that were abnormal in morphology on light and/or electron microscopy and by cytochemical stains. The eosinophils constituted 1%-24% of nucleated marrow cells. Of 61 acute nonlymphocytic leukemia (ANLL) patients, all those with AMMoL and abnormal bone marrow eosinophils had an inv(16) or a t(16;16). One other patient in this group had a rearrangement of chromosome 16 (with a break in the short arm at band p13); however, the ANLL type was M1 and no abnormal eosinophils were present. Four patients with ANLL types other than M4 had an increase in marrow eosinophils; three in whom the eosinophils appeared normal and one with ANLL-M2 and bizarre eosinophils morphologically distinct from those seen in AMMoL . Chromosome pair 16 was normal in the latter four patients. AMMoL with dysplastic bone marrow eosinophils appears to represent a unique clinicopathologic entity associated with several related abnormalities affecting 16q . The morphologic features of both blasts and eosinophils may be more important than the absolute number of eosinophils in the marrow in identifying this group of patients. This may have prognostic importance as five of six patients achieved complete remission with standard antileukemic therapy and are still alive.

Adult↗
PubMed1984

Hemoglobin D "Los Angeles" in an Austrian family: biochemical identification, clinical aspects, and kindred study.

During a screening program for gestational diabetes, hemoglobin D "Los Angeles" (beta 121 Glu----Gln) was detected by HPLC in an overweight but healthy pregnant Austrian woman. The chromatogram of the hemolysate revealed an unusual splitting of the hemoglobin A1 peak. Sequential analysis of the abnormal peptide indicated hemoglobin D "Los Angeles" heterozygosity in the patient. This is the first description of this variant in Germanic-appearing people. In a kindred study of 49 of the 57 living family members spanning four generations, 22 were heterozygous for hemoglobin D "Los Angeles". How this gene got to this region of Austria is unknown, but transfer via Iran and Turkey seems likely.

Austria↗
PubMed1984

[Somatomedin activity in Wiedemann-Beckwith syndrome].

Two patients with Wiedemann-Beckwith-Syndrome and neonatal hypoglycemia are reported. The etiology for the impaired glucose metabolism has not been elucitated as yet. In some patients pancreatic islet-cell hyperplasia resulting in hyperinsulinemic hypoglycemia was suspected. Increased somatomedin activity was also proposed. We have measured somatomedin concentrations in both patients by bioassay and radioimmunoassay and found normal or slightly reduced plasma levels with both methods.

Asphyxia Neonatorum↗
PubMed1984

Unusual karyotypic changes and B cell involvement in a case of lymph node blast crisis of chronic myelogenous leukemia.

A patient with Philadelphia chromosome (Ph1) positive chronic myelogenous leukemia (CML) entered a blast crisis localized to lymph nodes. On light microscopy, by morphology and histochemical staining, the blasts were undifferentiated. In spite of terminal deoxynucleotidyl transferase positivity, some of the lymph node cells expressed a myeloid differentiation antigen, OKM1, and were peroxidase positive by transmission electron microscopy (TEM). However, the majority of cells were peroxidase negative on TEM and expressed OKT-10, a marker found on both primitive myeloid and lymphoid cells. Cultures of lymph node cells stimulated with Epstein-Barr virus or lipopolysaccharide (LPS) revealed the Ph1, indicating B cell involvement in the CML. T cells from cultures stimulated with L4-phytohemagglutinin and T cell growth factor were negative for the Ph1. In unstimulated lymph node cells, the uncomplicated Ph1 could not be demonstrated; instead, a unique complex karyotype involving a masked Ph1 was identified in these and the LPS cultures. This karyotype was not found in bone marrow (BM) metaphase cells. Instead, BM cells showed either the simple Ph1 or the Ph1 with a rearrangement involving chromosomes 13 and 20. The patient had transient responses to three chemotherapy regimens, two of which were designed to treat acute lymphocytic leukemia, but he died 8 months after disease acceleration without BM blast crisis. These findings are compatible with an extramedullary blast crisis originating in a primitive cell with both myeloid and lymphoid characteristics.

Adult↗
PubMed1983

[Rhesus immunization from a neonatological viewpoint. What is today's crucial aspect?].

The ultimate goal in the treatment of neonatal Rh-disease is prevention of hyperbilirubinemia and bilirubin encephalopathy syndrome. Therapeutic approaches as exchange transfusion, phototherapy, reduction of enterohepatic circulation and enzyme induction are discussed on the basis of bilirubin metabolism. The impact of endogenous and exogenous factors upon bilirubin-albumin binding is emphasized in more detail. Two main theories for the pathogenesis of bilirubin encephalopathy syndrome are currently under discussion: the cytotoxicity of the free, unbound bilirubin fraction or the transient opening of the blood brain barrier secondary to asphyxia, acidosis and hyperosmolarity.

Acidosis↗
PubMed1983

[Initial description of hemoglobin D Punjab in an Austrian family].

Haemoglobin D Punjab was detected in a slightly overweight, but otherwise healthy pregnant woman when she was tested for gestational diabetes within the framework of a screening programme. Chromatographic evaluation of the haemolysate by high-pressure liquid chromatography (HPLC) revealed an unusual "splitting" of the A1 peak into two minor peaks. A diabetes-independent haemoglobin variant was suspected and further investigations, including electrophoresis, purification and sequential analysis of the tryptic peptide, identified the abnormal haemoglobin as haemoglobin D Punjab (beta 121 Glu-Gln). This is the first report of this haemoglobin variant in Austria. Various possible modes of geographical spreading of the gene from Punjab (India) are discussed, the land-route via Turkey being the most favourable hypothesis in this case. An investigation of 6 out of 7 living members of the family was undertaken. In 3 instances haemoglobin D Punjab was confirmed by HPLC and electrophoresis. The investigation of the family is currently being expanded to include a total of five generations.

Adult↗
PubMed1983

[Identification of hemoglobin D Punjab (beta 121 glu replaced by gln) in an Austrian family. Sequence analysis of the abnormal tryptic peptide beta XTp13].

In the course of a screening programme for gestational diabetes an abnormal haemoglobin fraction was detected by high-performance liquid chromatography (HPLC), used for Hb A1c-quantification. Cellulose acetate electrophoresis revealed a heterozygote haemoglobinopathy with approximately equal amounts of Hb A1 and of an abnormal haemoglobin which migrated in the position of Hb S under the conditions used. Preparative separation of these haemoglobin components was performed by use of a DEAE-cellulose column and standard conditions. alpha- and beta-chains were isolated with CM-sepharose and buffer containing 8M urea. The abnormal component of the aberrant haemoglobin was found to be the beta-chains in reconstitution experiments with globin-chains and haemin. A tryptic hydrolysate of the isolated abnormal beta-chains was analysed by means of HPLC and a C2 reverse phase (RP2). Rechromatography of the abnormal fractions on a C18 reverse phase (ODS) led to a pure preparation of peptide beta XTp13. The amino acid sequence analysis of this peptide showed an exchange of glutamic acid to glutamine in position beta 121 (beta 121 Glu----Gln). By these means evidence was obtained for the existence of a heterozygote Hb D Punjab state in the observed patient.

Adult↗
PubMed1983

[Non-enzymatic glycosylation of hemoglobin and serum protein in children with galactosemia].

Non-enzymatic galactosylation has been investigated by in vitro incubation of red cell haemolysate, a HbAo-preparation and of GBM of healthy children. The effects of non-enzymatic galactosylation of haemoglobin has been studied by high pressure liquid chromatography, the effects of GBM galactosylation by immunoelectrophoresis. Subsequently, the occurrence of elevated values for HbAIa-c and GSP was evaluated in 14 galactosaemic children (11 transferase deficiency, 3 galactokinase deficiency), as well as urinary acid glycosaminoglycae excretion and GBM immunoelectrophoretic mobility in 6 of these 14 children measured. The results were compared to the respective values of healthy control children. After exclusion of significant non-enzymatic glucosylation by measuring postprandial blood glucose values the galactosaemic children showed significantly increased values for HbAIa-c (8.85 +/- 2.0% versus 7.7 +/- 0.3%; p less than 0.02), for GSP (0.43 +/- 0.13 mmol 5-HMF/mg protein versus 0.32 +/- 0.07 mmol 5-HMF/mg protein; p less than 0.005) as well as for urinary acid glycosaminoglycane excretion (45.3 +/- 23.4 micrograms/mg kreatinine versus 9.9 +/- 2.3 micrograms/mg Kreatinine; p less than 0.01). 3 out of the 6 children showed alpha 1-immunoelectrophoretic mobility of GBM antigens which was found also after incubation of GMB with galactose. The other 3 children had alpha 2-immobility, which was found in the healthy controls as well as in the control incubations. The impact of galactose on increased non-enzymatic glycosylation in children with galactosaemia as well as the significance of this finding for diagnostic purposes or for clarifying pathophysiological aspects of the disease remains to be studied further.

Adolescent↗
PubMed1983

Inhibition of alkaline phosphatase activity by glucose.

Non-enzymatic glycosylation (NEG) of alkaline phosphatase (AP) was studied after short- and long-term incubation with glucose and other carbohydrates. Glucose and amino sugars clearly inhibited the enzyme activity; this was in contrast to reducing and non-reducing disaccharides, which had an enhancing effect. After AP had been incubated with 18 nmol/l glucose for 180 minutes (short-term incubation), a subsequent extensive dialysis revealed full recovery of the enzymatic activity. This, plus the demonstration of a [3H]sodium borohydride-reducible glucose-protein adduct, indicated that initially a labile aldimine (Schiff base) had been formed. Binding experiments with [14C]glucose and failure of dialysis to achieve a recovery of enzymatic activity after long-term incubation suggested that subsequently a stable ketoamine product had been formed. This was further confirmed by the thiobarbituric acid test, which revealed 0.65 nmol 5-hydroxymethylfurfural/mg protein for glycosylated AP compared to 0.11 for the non-glycosylated control. Preliminary results further suggest that NEG of AP also occurs in vivo. Streptozotocin diabetic rats had significantly lower serum AP activities than did non-diabetic controls (mean +/- SD: 153.7 +/- 28.4 vs. 760.5 +/- 95.7 U/l; p less than 0.001). Blood glucose levels and serum AP activity, which had been determined simultaneously during an oral glucose tolerance test, showed without exception an inverse relationship in each of 32 healthy children studied. The biological significance of these findings remains to be established.

Adolescent↗
PubMed1983

Persistence of herpes simplex virus type-2 genome in a human leukemic cell line.

To study the nature of virus-cell interaction in persistently infected cells we have examined production of infectious virus, synthesis of viral DNA and DNA polymerase in a human leukemic cell line K562. It was found that only one of three K562 cell lines was permissive for limited growth of HSV-2 and infectious virus was released in a cyclical fashion. Intranuclear inclusions with electron-dense fibrils and particles resembling viral structures were observed in the virus-infected but not control K562 cells. Viral DNA synthesis could not be detected by centrifugation in CsCl density gradients; but was readily identified by Southern blot hydridization of virus-infected intracellular DNA with purified viral DNA. Viral DNa polymerase was synthesized by infected cells during active infectious virus production. In one of the two K562 cell lines that did not produce infectious virus, a few DNA fragments from infected cells were found to hybridize with purified viral DNA. These results suggest that variable lengths of HSV-2 genome can be harbored and propagated by different human leukemic K562 cells.

Cell Line↗
PubMed1983

[Manifold reflection infrared spectroscopy of the hair of mice with an experimental amino acid metabolism disease (L-acetidin-2-carboxylic acid incorporation instead of proline). A model for the use of infrared spectroscopy as a screening method for metabolic diseases].

8 mice were given L-acetidin-2-carboxylic acid orally over a period of 5 weeks. Another 8 mice served as control animals. Finally, the mice were sacrificed, their hair samples were hydrolized and applied to thin layer chromatography which revealed the incorporation of L-acetidin-2-carboxylic acid into mouse hair expressed by an additional spot. This experimental amino acid metabolic disorder served as a model for the application of infrared spectroscopy for screening hair in order to check metabolic disorders. As the multiinternal reflection-infrared spectra showed significant differences we suggest that infrared spectroscopy can be used as a noninvasive screening technique.

Amino Acid Metabolism, Inborn Errors↗
PubMed1983

[Incorporation of L-acetidine-2-carboxylic acid in type I skin collagen. Biochemical and mechanoelastic properties].

In order to elucidate the role of L-acetidine-2-carboxylic acid (L-ac) incorporated into collagen type I of the skin instead of proline, we looked for the mechanoelastic properties of skin. Mice were orally fed with 0, 1% solution of L-ac for 5 weeks, then sacrificed, and type I collagen was extracted. Incorporation of the proline analogue (L-ac) could be shown by two dimensional thinlayer chromatography. The melting point (Tm) of type I collagen was determined by circular dichroism: 36, 5 +/- 1 degrees C for normal collagen, 37 +/- 1 degrees C for L-ac-collagen. This insignificant difference indicates that there was no alteration of the thermal stability of the collagen helix after incorporation of L-ac. Tensile strength was examined on whole strips of skin and worked out at means = 1,00 N/mm, s = 0,20 N/mm, sigma = 0,04 N/mm for normal individuals and means = 0,62 N/mm, s = 0,24 N/mm, sigma = 0,05 N/mm for L-ac-fed animals. The considerable difference could be estimated by the Wilcoxon test (p less than 0,005). As the stability of the collagen helix (shown through melting point determination) has not decreased, the reduced mechanoelastic property of tensile strength seems to be due to intermolecular rather than to intramolecular disturbances of the cross connection of the triple helix.

Animals↗
PubMed1983

[Hemoglobin A1 in a diabetic with thalassemia minor].

HbA1 levels of 22.6% were found in a 67-year-old woman with type II diabetes mellitus. Haemoglobin electrophoresis and peripheral blood count proved the diagnosis of thalassaemia minor (HbF thalassaemia). The coincidence of diabetes mellitus and increased haemoglobin F is rare (0.01 per 1000 or less) in Central Europe, with the exception of the southern mediterranean countries. In the reported case the levels for HbA1, measured by the colorimetric thiobarbiturate method, and the difference both between HbA2 (micro-column chromatography) as well as HbF values, corresponded to the blood sugar concentrations. These methods are thus suitable in the rough estimation of long-term metabolic control in patients with diabetes mellitus and increased haemoglobin F, such as HbF thalassaemia.

Aged↗
PubMed1983

Serum apolipoproteins and lipoprotein (a) during the first week of life.

The levels of apolipoproteins, A-I, A-II, B and E, lipoprotein (a) and of total cholesterol and triglycerides were determined in cord serum and in capillary serum at the fifth day of life in a group of 44 term newborns. Additionally, cord serum lipoproteins were estimated. Sera from 26 healthy adults were studied for comparison. The concentrations of lipids and lipoproteins in cord serum were diminished as compared to adult levels. The occurrence of lipoprotein (a) in cord serum in concentrations significantly lower than in adults could be established. Serum apolipoproteins A-I, A-II and B were significantly lower at birth than in the adult, whereas apolipoprotein E levels did not differ from adult concentrations. During the first five days apolipoprotein B levels more than doubled, apolipoprotein A-I increased moderately and apolipoprotein E rose slightly. In contrast, serum lipoprotein (a) and apolipoprotein A-II did not change significantly. Unlike serum cholesterol, the levels of apolipoproteins B and E at day five were significantly correlated to those measured at birth in the same infants. The changes of the apolipoprotein pattern during the first week of life reflect the evolution of the lipid transport system of the newborn and may be related to the increasing utilisation of fat and to hormonal factors.

Adult↗
PubMed1983

Enzymatic reversibility of nonenzymatic glycosylation of the glomerular basement membrane. Is the diabetic glomerulopathy principally reversible?

Recent investigations point to the nonenzymatic glycosylation as a cause of long-term complications in diabetes mellitus. We describe an enzymatic activity that cleaves glucose from the glomerular basement membrane (GBM), present in lysosomal preparations of diabetic lymphocytes. The GBM, nonenzymatically glycosylated or obtained from rats with diabetes, were incubated with enzyme preparations, separated on Sephadex G-25 and applied for glucose measurement on gas chromatography and mass spectroscopy. The lysosomal preparation of diabetic lymphocytes cleaved from rat GBM, which were nonenzymatically glycosylated 300-500 ng glucose/mg GBM protein, from diabetic rat GBM 300 ng glucose/mg GBM protein. A lysosomal preparation of normal lymphocytes failed to do so, indicating enzyme induction in the diabetic state. Control studies with the glycosylated hemoglobin AIc confirmed this finding and showed the specificity of the enzyme, as alpha-glucosidase and beta-glucosidase failed to cleave the N-glycosidic bond between glucose and the protein. The enzymatic activity can be described formally as a N-l-deoxyfructofuranosyl-glucohydrolase, which could be responsible for a potential reversibility of diabetic GBM changes.

Animals↗