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Biomedical subjects

V Gross

Publications and source records attributed to V Gross.

At least 181 records · Page 10Linked to original sources
PubMed1984

TSH secretion in thalassemia.

Thyroid function has been evaluated in 6 prepubertal male and 9 female thalassemic patients. Four of the latter were sexually immature (Group I), with very low estradiol levels and the remainder had more advanced sexual development (Group II). Subjects were challenged with TRH and the response compared to adult controls and a group of 15 males aged 13-18 years with constitutional delayed adolescence. All patient groups and controls had normal levels of T4, T3 and T3 resin uptake. When compared to adult controls or males with constitutional delayed adolescence, the male thalassemic patients had increased basal TSH levels with an exaggerated response to TRH. Long term testosterone enanthate led to a decrease in integrated TSH secretion, showing that androgens may decrease the TSH response to TRH. The more sexually mature females of Group II also had increased basal and stimulated TSH levels; however, the sexually immature females of Group I had basal TSH and TSH responses to TRH equivalent to female controls. In Group I patients there were, moreover, no changes in TSH response during administration of estradiol valearate for 3 months and conjugated estrogens for 8 months. The high basal and stimulated TSH levels in the males and Group II females are most likely due to subclinical primary hypothyroidism. This has been previously described in thalassemia. On the other hand, failure of estrogens to increase the TSH response to TRH in Group I females is evidence of pituitary involvement, which is also well documented in this clinical condition.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1984

Induction of acute phase proteins by dexamethasone in rat hepatocyte primary cultures.

The effect of dexamethasone on the synthesis of acute phase proteins has been studied in primary cultures of rat hepatocytes. In the absence of dexamethasone no detectable amounts of alpha 2-macroglobulin were synthesized by hepatocytes cultured for 1 day. alpha 2-Macroglobulin synthesis was induced by dexamethasone concentrations of 10(-8) M or higher with a maximum at a concentration of 10(-7) M. alpha 1-Acid glycoprotein was synthesized in the absence of dexamethasone; however, its synthesis was also greatly stimulated by dexamethasone concentrations of 10(-8)-10(-6) M. Synthesis of alpha 1-proteinase inhibitor was stimulated only 1.4-fold at a dexamethasone concentration of 10(-7) M. The kinetics of induction of alpha 2-macroglobulin and alpha 1-acid glycoprotein were studied at a dexamethasone concentration of 10(-7) M. After an initial lag phase of 3 h the synthesis of both proteins showed a steady increase during 2 days. Synthesis of albumin remained unchanged under these experimental conditions. Unlike alpha 2-macroglobulin and alpha 1-acid glycoprotein tyrosine aminotransferase activity increased already during the first 3 h of induction by dexamethasone with a maximum at 12 h followed by a slight decrease.

Acute-Phase Proteins↗
PubMed1984

Growth and sexual development before and after sex steroid therapy in patients with thalassemia major.

Growth, sexual development, and hypothalamic-pituitary-gonadal function were evaluated in 23 patients with thalassemia major (14 female and nine male) aged 13 to 29 years. Five women (group 1) with hemoglobin levels of less than 7 g/dL, which were maintained by transfusions during childhood, did not spontaneously enter puberty. They had evidence of severe hypothalamic-pituitary dysfunction. Maintaining hemoglobin levels of about 8 g/dL resulted in spontaneous onset of puberty in seven of nine female patients (group 2), but had no such ameliorative effect on the nine male patients. In the latter, peak luteinizing hormone (LH) responses to gonadotropin releasing hormone correlated with bone age. Treatment with testosterone produced inconsistent partial inhibition of LH and follicle-stimulating hormone (FSH) responses to stimulation. After discontinuation of testosterone treatment, a rebound of basal testosterone, LH, and FSH levels was observed, but this was not sustained. These findings are compatible either with dysfunction of hypothalamic maturation or with partial pituitary dysfunction. Four of the group 1 females and six of the males treated with appropriate sex hormones showed satisfactory pubertal progression. Acceleration in linear growth was observed in four of the male patients whose epiphyses were still open. Treatment was well tolerated in all patients.

Adolescent↗
PubMed1983

Cell-free synthesis of rat alpha 2-macroglobulin and induction of its mRNA during experimental inflammation.

Poly(A)-rich RNA was isolated from the livers of acutely inflamed rats by extraction with guanidinium HCl and oligo(dT)-cellulose chromatography. After translation in a recticulocyte lysate and immunoprecipitation with a specific antiserum to alpha 2-macroglobulin a polypeptide with an apparent molecular weight of 162000 could be detected. The cell-free synthesis of alpha 2-macroglobulin was stimulated 8-fold by the addition of RNase inhibitor. Full-length alpha 2-macroglobulin polypeptide chains appeared after 35 min in the presence of 1.85 mM Mg2+ and 100 mM K+. A nucleotide number of about 5100 was estimated for alpha 2-macroglobulin by means of sucrose gradient centrifugation of poly(A)-rich RNA followed by translation in vitro and immunoprecipitation of alpha 2-macroglobulin. In normal liver alpha 2-macroglobulin mRNA represented about 0.0007% of total translatable RNA. Acute inflammation generated by intramuscular injection of turpentine led to a 66-fold increase in translatable alpha 2-macroglobulin mRNA after 18 h, followed by a rapid decrease. In accordance to the induction of alpha 2-macroglobulin mRNA serum concentrations of alpha 2-macroglobulin increased to about 2 mg/ml. Unlike alpha 2-macroglobulin mRNA serum alpha 2-macroglobulin levels remained unchanged up to 60 h.

Animals↗
PubMed1983

Interaction of mature, unglycosylated and cell-free synthesized rat alpha 1-proteinase inhibitor with elastase.

Purified rat alpha 1-proteinase inhibitor (Mr 54 000) and porcine pancreatic elastase (Mr 26 000) formed a complex (Mr 82 000) resistant to heat treatment under denaturing and reducing conditions. A similar alpha 1-proteinase-inhibitor-elastase complex was detected by immunoprecipitation of alpha 1-proteinase inhibitor from the medium of [35S]methionine-labeled hepatocyte primary cultures after incubation with elastase. Treatment of hepatocytes with tunicamycin led to the secretion of an unglycosylated alpha 1-proteinase inhibitor (Mr 41 000) which also formed a complex with elastase (Mr 66 000). Complex formation (Mr 68 000) could also be observed between cell-free synthesized pre-alpha 1-proteinase inhibitor (Mr 43 000) and elastase (Mr 26 000). The results suggest that neither glycosylation nor removal of the signal peptide are required for the formation of a biologically active conformation of alpha 1-proteinase inhibitor.

Animals↗
PubMed1983

1-deoxynojirimycin impairs oligosaccharide processing of alpha 1-proteinase inhibitor and inhibits its secretion in primary cultures of rat hepatocytes.

1-Deoxynojirimycin was found to inhibit oligosaccharide processing of rat alpha 1-proteinase inhibitor. In normal hepatocytes alpha 1-proteinase inhibitor was present in the cells as a 49,000 Mr high mannose type glycoprotein with oligosaccharide side chains having the composition Man9GlcNAc and Man8GlcNAc with the former in a higher proportion. Hepatocytes treated with 5 mM 1-deoxynojirimycin accumulated alpha 1-proteinase inhibitor as a 51,000 Mr glycoprotein with carbohydrate side chains of the high mannose type, containing glucose as measured by their sensitivity against alpha-glucosidase, the largest species being Glc3Man9GlcNAc. Conversion to complex oligosaccharides was inhibited by the drug. In addition, increasing concentrations of 1-deoxynojirimycin inhibited glycosylation resulting in the formation of some alpha 1-proteinase inhibitor with two instead of three oligosaccharide side chains. 5 mM 1-deoxynojirimycin inhibited the secretion of alpha 1-proteinase inhibitor by about 50%, whereas secretion of albumin was unaffected. The oligosaccharides of alpha 1-proteinase inhibitor secreted from 1-deoxynojirimycin-treated cells were characterized by their susceptibility to endoglucosaminidase H, incorporation of [3H]galactose, and [3H]fucose and concanavalin A-Sepharose chromatography. It was found that 1-deoxynojirimycin did not completely block oligosaccharide processing, resulting in the formation of alpha 1-proteinase inhibitor molecules carrying one or two complex type oligosaccharides. Only these alpha 1-proteinase inhibitor molecules processed to the complex type in one or two of their oligosaccharide chains were nearly exclusively secreted. This finding demonstrates the importance of oligosaccharide processing for the secretion of alpha 1-proteinase inhibitor.

1-Deoxynojirimycin↗
PubMed1983

Messenger RNA activities of four acute phase proteins during inflammation.

Poly(A)+ RNA isolated from the livers of normal rats and of rats suffering from an acute inflammation was translated in a cell-free translation system from rabbit reticulocytes. The translation products were immunoprecipitated with specific antisera against alpha 1-acid glycoprotein, alpha 2-macroglobulin, transferrin, alpha 1-proteinase inhibitor and albumin. 15 to 21 h after intramuscular injection of turpentine 73-, 66-, 2.8-, and 2-fold increases in translatable mRNAs for alpha 1-acid glycoprotein, alpha 2-macroglobulin, transferrin and alpha 1-proteinase inhibitor, respectively, were observed. For albumin a decrease in translatable mRNA to about 30% of controls was measured.

Animals↗
PubMed1983

The biosynthesis of acute-phase proteins in primary cultures of rat hepatocytes.

The biosynthesis and secretion of alpha 2-macroglobulin, transferrin, alpha 1-acid glycoprotein and alpha 1-proteinase inhibitor were studied in rat hepatocyte primary cultures. After labeling with [35S]methionine, two forms, which can be separated electrophoretically differing by molecular weight, were found for each of the four glycoproteins. The following molecular weights were estimated for the intracellular precursors and the secreted forms: alpha 2-macroglobulin, 176 000 and 182 000; transferrin, 84 000 and 86 000; alpha 1-acid glycoprotein, 39 000 and 43 000-60 000; alpha 1-proteinase inhibitor, 49 000 and 54 000. Carbohydrate moieties could be removed from intracellular forms by treatment with endoglucosaminidase H indicating that their oligosaccharide chains were of the high-mannose type. The extracellular forms were sensitive to sialidase. They incorporated [3H]galactose and [3H]fucose showing that their oligosaccharide chains were of the complex type. Pulse-chase experiments revealed a precursor-product relationship for the high-mannose and the complex type glycoproteins. In the hepatocyte medium newly synthesized albumin was detected after 30 min and newly synthesized glycoproteins after 60 min. Unglycosylated alpha 2-macroglobulin (162 000), transferrin (79 000), alpha 1-acid glycoprotein (23 000), and alpha 1-proteinase inhibitor (41 000) were found in the cells as well as in the medium, when the transfer of oligosaccharide chains onto the polypeptide chains was blocked by tunicamycin. Tunicamycin led to a marked reduction of the secretion of alpha 2-macroglobulin, alpha 1-acid glycoprotein and alpha 1-proteinase inhibitor, whereas the secretion of transferrin was less affected.

Animals↗
PubMed1983

Effect of swainsonine on the processing of the asparagine-linked carbohydrate chains of alpha 1-antitrypsin in rat hepatocytes. Evidence for the formation of hybrid oligosaccharides.

The biosynthesis of the proteinase inhibitor alpha 1-antitrypsin has been studied in rat hepatocyte primary cultures. Newly synthesized alpha 1-antitrypsin was found in hepatocytes as a glycoprotein of an apparent molecular weight of 49,000 carrying oligosaccharide side chains of the high mannose type. In the hepatocyte medium a secreted alpha 1-antitrypsin of an apparent molecular weight of 54,000 could be identified as a glycoprotein with carbohydrate chains of the complex type. Pulse-chase experiments revealed a precursor-product relationship for the two forms of alpha 1-antitrypsin. When the hepatocytes were treated with swainsonine, an intracellular form of alpha 1-antitrypsin with an apparent molecular weight of 49,000 indistinguishable from that of control cells was found. However, the alpha 1-antitrypsin secreted from swainsonine-treated hepatocytes was different from that present in control media. It was characterized by a lower apparent molecular weight (51,000), a higher amount of [3H]mannose incorporation, half as much incorporation of [3H]galactose, and the same amount of [3H]fucose incorporation compared to alpha 1-antitrypsin of control media. In contrast to the 54,000 complex type alpha 1-antitrypsin from control media the 51,000 alpha 1-antitrypsin from the medium of swainsonine-treated cells was found to be susceptible to the action of endoglucosaminidase H, even when fucose was attached to the proximal GlcNAc residue. alpha 1-Antitrypsin secreted from swainsonine-treated cells combines features usually associated with either high mannose or complex type oligosaccharides and therefore represents a hybrid structure. In spite of its effect on the carbohydrate part of alpha 1-antitrypsin swainsonine did not impair the secretion of the incompletely processed glycoprotein.

Alkaloids↗
PubMed1983

N-terminal amino acid sequences of precursor and mature forms of alpha-1-antitrypsin.

alpha-1-Antitrypsin is found in hepatocytes as a high-mannose glycoprotein (Mr 49 000), extracellularly as a complex-type glycoprotein (Mr 54 000). Deglycosylation of both forms with peptide: N-glycosidase led to proteins of identical app. Mr (41 000). The sequence of 26 N-terminal amino acids of rat alpha 1-antitrypsin was determined. A high content of polar amino acids was found. The partially characterized presequence of in vitro synthesized alpha 1-antitrypsin showed a cluster of hydrophobic amino acids. A pre-peptide of 24 amino acids is proposed. There is no evidence for the existence of a propeptide.

Amino Acid Sequence↗
PubMed1983

Synthesis of alpha 2-macroglobulin in rat hepatocytes and in a cell-free system.

The biosynthesis and secretion of alpha 2-macroglobulin was studied in rat hepatocyte primary cultures. After immunoprecipitation of alpha 2-macroglobulin from a cell homogenate and the hepatocyte medium, two forms of alpha 2-macroglobulin with app. Mr of 176000 and 182000, respectively, were identified. A precursor-product relationship for the two alpha 2-macroglobulin forms was demonstrated by a pulse-chase experiment. The cellular form of alpha 2-macroglobulin could be deglycosylated by endoglucosaminidase H, whereas the medium form of alpha 2-macroglobulin remained unaffected. On the other hand, only the medium form of alpha 2-macroglobulin was found to be susceptible to neuraminidase. In vitro translation of rat liver poly(A)+ RNA resulted in a translation product of an app. Mr of 162000.

Animals↗
PubMed1982

Biosynthesis and secretion of alpha 1-antitrypsin in primary cultures of rat hepatocytes. Characterization of differently glycosylated intracellular and extracellular forms.

The biosynthesis and secretion of alpha 1-antitrypsin was studied in rat hepatocyte primary cultures. After labeling with [35S]methionine an alpha 1-antitrypsin with an apparent molecular weight of 49000 estimated by sodium dodecyl sulfate/polyacrylamide slab gel electrophoresis was immunoprecipitated from the cell homogenate. This intracellular form of alpha 1-antitrypsin could be deglycosylated by endoglycosidase H treatment indicating that its oligosaccharide chains were of the high-mannose type. Pulse-chase experiments showed that about 30 min after its synthesis the transformation of the 49000-Mr alpha 1-antitrypsin to a protein with an apparent molecular weight of 54000 began. Only this 54000-Mr protein was secreted by the hepatocytes. The 54000-Mr alpha 1-antitrypsin was not sensitive to endoglycosidase H, but sensitive to neuraminidase, and it incorporated [3H]galactose and [3H]fucose indicating that its oligosaccharide chains were of the complex type. In the presence of tunicamycin, which blocks the formation of N-asparagine-linked oligosaccharide chains, an unglycosylated alpha 1-antitrypsin with an apparent molecular weight of 41000 was found in the cells as well as in the medium. However, tunicamycin decreased the secretion of alpha 1-antitrypsin by 60-70%, whereas the secretion of albumin remained unaffected. In the presence of colchicine the secretion of both alpha 1-antitrypsin and albumin was impaired. The results demonstrate the importance of glycosylation for the secretion of alpha 1-antitrypsin.

Animals↗
PubMed1982

[Correlation of erythrocyte sodium concentration and the KG-value in variable peripheral insulin levels].

In pregnant women with physiological hyperinsulinism and in a control group with lower peripheral insulin concentrations after glucose load was investigated, whether differences in the peripheral insulin content involve different relations between the KG-value and the sodium concentration of the erythrocytes. Despite the differences in the peripheral insulin content during the intravenous glucose tolerance test negative correlations between the KG-value and the sodium concentration of the erythrocytes were found in the groups investigated. From this was concluded that these correlations are not based on changes of the peripheral insulin level, as they were established in the present examinations. A conception was presented issuing from the fact that the negative correlation between the KG-value and the sodium concentration is based on properties of the cell membrane which influence the intracellular sodium concentration as well as the effect of insulin in the cell.

Adult↗
PubMed1982

[Fatty acid patterns of triglycerides in serum and skeletal muscles of rabbits on a cholesterol diet].

In 18 rabbits a hypercholesterolaemia was produced by a 12-week dietetic load with cholesterol. The hypercholesterolaemic rabbits had increased proportions of saturated and simply unsaturated fatty acids in the triglycerides of the serum and the skeletal muscle. The content of eicosapentaenic acid was lowered. The alterations in the fatty acid pattern are equal to those of patients with hyperlipoproteinaemia and arteriosclerosis. On the basis of these findings rabbits seems to be a suitable model, in order to investigate the connections between fatty acid patterns and the development of arteriosclerosis by experiments on animals.

Animals↗
PubMed1982

Pancreatitis as a complication of Henoch--Schonlein purpura.

A 5-year-old girl suffering from Henoch--Schonlein purpura developed severe abdominal pain accompanied by vomiting and fever. Concomitantly, the serum amylase level became elevated and leukocytosis developed, with a shift to the left. A diagnosis of pancreatitis complicating Henoch--Schonlein purpura was made. This rare complication is presented, along with a review of the literature.

Child, Preschool↗