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Biomedical subjects

S Fischer

Publications and source records attributed to S Fischer.

At least 469 records · Page 26Linked to original sources
PubMed1982

Phosphorylations of the subcellular matrix in cells transformed by Rous' sarcoma virus.

The transforming protein of Rous' sarcoma virus (RSV) is a phosphoprotein of Mr 60 000 (pp60src) which displays protein kinase activity specific for tyrosine residues; pp60src is associated with the plasma membrane and is recovered in the detergent-insoluble material which represents the subcellular matrix of the cell. After phosphorylation of this material of RSV-transformed cells with [gamma-32P]ATP, five phosphoproteins have been detected which are not seen in normal cells. These proteins (Mr = 135 000, 125 000, 75 000, 70 000, 60 000) contain phosphotyrosine. Their phosphorylation is strongly inhibited by anti-pp60src antibodies. In cells transformed by a temperature-sensitive mutant of RSV, these phosphoproteins, present at the permissive temperature, are no longer detected at the non-permissive temperature. It is concluded that these phosphorylations are mediated by pp60src protein kinase activity. This supports a possible role of the phosphorylation of cytoskeletal proteins in the transformation process.

Avian Sarcoma Viruses↗
PubMed1982

Diagnostic bone-marrow studies extended routinely by iliac crest biopsy, using the method of Schaadt-Fischer.

The value of routinely including biopsy of the iliac crest in the haematological diagnostic programme in medical departments of haematology is elucidated by analysis of 129 biopsies. At the same time, imprints of the biopsies and aspirate smears were compared as regards diagnostic efficacy, which proved 15% greater for imprints and biopsies. The frequency of an inadequate bone biopsy was 7.7%, often because the biopsies were less than 5 mm in length (16%). The individual categories, bone biopsy, imprint, and aspiration smears were of equal diagnostic efficacy in 76%. Guidance for the haematological diagnosis was obtained in 80% of the cases. The incidence of dry tap was 1.6% and the complication rate 1.6%. The optimal result, viz. sufficiently long biopsies (54% over 10 mm in length), is obtained by taking the biopsy with a conically tipped needle (the Jamshidi or Schaadt-Fischer needle) and by making imprints before embedding the biopsies in methacrylate JB IV. The preparation and safety measures in embedding in JB IV and subsequent special staining, including cytochemical studies, are described. By the technique used, it is possible, with some practice, to obtain adequate biopsies in 80-90% of all patients and to take a biopsy and perform aspiration in one session. The patient's position, lying on his side, seems to make him less apprehensive.

Biopsy, Needle↗
PubMed1982

[Immunological examinations in dilated cardiomyopathies].

Immunological data in dilated cardiomyopathies can differentiate the nosology of these diseases. In nearly one half of these dilated cardiomyopathies, binding of immunoglobuline in myocardial structures (biopsies) can be demonstrated. By immunohistological techniques collagen I in myocardial biopsies has been predominantly shown. In lymphocytes of the diseases patients the T-cell-suppressor activity is low. This phenomenon seems to play an important role in the pathogenesis of dilated cardiomyopathies and can explain numerous humoral immunological findings. As conclusion the hypothesis can be drawn: several cases of dilated cardiomyopathies and myocarditis can be regarded as different stages of a single underlying disease, in which a low T-cell-suppressor activity seems to act as a predisposing factor.

Antibody Formation↗
PubMed1981

Bilateral ovarian lipid cell hyperplasia in a young hirsute patient.

Virilizing lipid cell ovarian hyperplasia occurred in a 24-year-old woman referred with secondary amenorrhea, hirsutism, and weight gain. Hormone analyses revealed abnormal androgen production shown in a suppression test to be autonomic and of ovarian origin. Ovarian vein catheterization revealed abnormally increased androgen levels in the left ovarian vein and in the caval vein where it was entered by the right ovarian vein. As the patient wanted to become pregnant, three-quarters of her ovarian tissue was resected. Menstruation and ovulation returned. Two years after the operation the patient conceived. Histopathological and electron microscopic examinations revealed bilateral lipid cell hyperplasia.

Adult↗
PubMed1981

[Defective type I collagen in a woman patient with juvenile idiopathic scoliosis (author's transl)].

The molecular causes of idiopathic scoliosis have not yet been clarified to any appreciable extent and are probably heterogeneous. The occurrence of scolioses in congenital diseases of the connective tissue points to changes in connective tissue metabolism. Collagen is the most essential structural connective tissue component of bone. It was the aim of our investigations to examine the synthesis of collagen of Types I and II in order to identify a possible molecular defect. In the woman patient examined by the authors, a pathologically changed alpha-chain of the collagen of Type I was found as the probable cause of this particular case of idiopathic scoliosis.

Adolescent↗
PubMed1981

Human kidney preservation by intracellular electrolyte flush followed by cold storage for over 24 hours.

Many transplant teams are reluctant to accept kidneys preserved with intracellular electrolyte flushing followed by simple cold storage when preservation time exceeds 24 hr. This study from one center is a comparison of 63 primary cadaver kidney grafts preserved with Collins 2 solution flush followed by cold storage for 9 to 23 1/2 hr to 42 primary cadaver kidney grafts preserved by the same method for 24 to 44 1/2 hr. Kidneys cold-stored for over 24 hr had a significantly increased requirement for dialysis in the first week following transplantation (55% versus 30%). One-month serum creatinine nadirs and actuarial graft survivals were not significantly different. Cadaver donor methylprednisolone (30 to 60 mg/kg) 2 to 9 hr prior to kidney removal reduced the requirement for first-week hemodialysis in the kidneys cold-stored for over 24 hr (23% versus 69%, P under 0.05). A human kidney preserved by the same method and cold-stored for 61 hr was successfully transplanted into a 38-year-old myelodysplastic. Satisfactory human kidney preservation can occur with intracellular electrolyte flush solutions followed by cold storage for over 24 hr when the warm ischemia time is very short.

Cold Temperature↗
PubMed1981

Problems in the diagnosis and management of acute pancreatitis.

Despite the lack of precise knowledge as to its exact mechanism of causation, acute pancreatitis continues to engage the clinician's attention. The world medical literature is replete with publications on the subject and the numerous Australian studies attest to the continuing clinical interest (Hennessy, 1965; Bennett and Jepson, 1966; Kune, 1968; Barraclough and Coupland, 1972; Battersby and Chapuis, 1977 and Reid and Kune, 1978). The majority of these reviews concentrate on the supposed aetiology and clinical features of acute pancreatitis and cover well trodden ground. It is the purpose of this paper to review the problems in the diagnosis and management of acute pancreatitis in the light of present knowledge and to relate these to 494 patients with acute pancreatitis admitted to St Vincent's Hospital, Melbourne, during the period 1968 to 1979. The diagnosis of acute pancreatitis in these 494 cases was made at operation, autopsy or by the demonstration of an elevation in the serum amylase above 1200 International units (I.U.) per litre in patients with compatible symptoms and signs.

Acute Disease↗
PubMed1981

Evidence for imbalanced furosemide-sensitive Na+, K+ cotransport in hereditary stomatocytosis.

The red cells from 5 related patients with hereditary stomatocytosis were investigated. Maximal rate constant of Na+ passive permeability was increased while that of K+ passive permeability was nearly normal. Ouabain-sensitive Na+ efflux was elevated. The Na+ component of furosemide-sensitive Na+, K+ cotransport was also increased. However, its K+ component, determined in 2 patients, remained within normal limits, thus departing from the strict 1:1 stoichiometry of the Na+, K+ cotransport system. Yet, intracellular Na+ and K+ concentrations displayed limited and inconstant changes. A variety of abnormally-shaped cells, including stomatocytes, were observed in scanning electron micrographs. Upon differential centrifugation, reticulocytes usually concentrated in the most dense region of the gradient. Red cell deformability, as studied by ektacytometry, was reduced. Membrane phosphatidylcholines and sphingomyelins were increased and decreased, respectively, where-as fatty acid distribution was unchanged. Membrane microviscosity was normal.

Cations↗
PubMed1981

Hormonally stimulated adenylate cyclase and cAMP dependent protein kinase in membranes of rabbit erythroid cells separated according to density.

Plasma membranes were prepared after density gradient separation of erythroid cells obtained from bled animals. In a fraction enriched in young reticulocytes (lowest density), the basal and the prostaglandin stimulated adenylate cyclase were greatly augmented if compared with the membranes from unfractionated cells or from the layers of higher densities. Potentiation by GTP or soluble factor(s) of the prostaglandin stimulated adenylate cyclase was found solely in the fractions containing the youngest cells (lowest density). A very significant augmentation of both the basal and the effectors stimulated adenylate cyclase was obtained when the white blood cells and the platelets were removed by filtration through alpha-cellulose prior to density separation. A small population of probably very young reticulocytes was shown to contain a very active adenylate cyclase coupled to the hormonal receptor. Upon short time of maturation this coupling could no longer be detected. The cAMP generated in the fraction enriched in young reticulocytes increased the phosphorylation of some membrane proteins. The presence of a hormonally regulated adenylate cyclase and eventually the phosphorylation of some specific membrane proteins by the cAMP generated in situ permit to envisage possible functions of this system in young reticulocytes.

Adenylyl Cyclases↗
PubMed1980

A spin label study of the erythrocyte membranes in Duchenne muscular dystrophy.

Red blood cells and freshly prepared erythrocyte membranes of 15 patients with Duchenne muscular dystrophy (DMD) as well as age-matched controls were studied by the spin label method. No significant modifications appeared for spin-labelled proteins of ghost membranes. With the two fatty acid spin labels, 5-nitroxide stearate and 16-nitroxide stearate, we have confirmed previous results of Sato et al. concerning the thermal behaviour of the erythrocyte membranes, i.e. no change near the polar part probed by 5-nitroxide stearate and a linearization of the fluidity versus temperature variation around 12 degrees C, as explored by 16-nitroxide stearate. Furthermore we studied in the whole erythrocyte the amplitude of the 5-nitroxide stearate electron spin resonance signal as a function of the microwave power. This saturation effect was observed in 12 out of 15 controls and only in 1 out of 13 DMD cases studied. In erythrocyte membranes labelled with 16-nitroxide stearate the penetration of the label inside membranes was statistically different between DMD and controls. These new findings furnish further arguments in favour of a structural alteration of the phospholipid organization of erythrocyte membranes in DMD. Associated together, these different sets of tests obtained by spin labelling permit good statistical discrimination between DMD and normal subjects.

Adolescent↗
PubMed1980

Phosphorylation and dephosphorylation reactions by erythrocyte plasma membrane enzymes.

Human erythrocyte membranes contain a phosphoprotein phosphatase able to dephosphorylate membrane protein previously phosphorylated by the endogenous protein kinase. The level of dephosphorylation obtained after prolonged incubation is about one half of the phosphorylated residues. The characteristics of this enzyme are similar to those described for the cytoplasmic phosphoprotein phosphatase. In a membrane preparation the phosphorylation and dephosphorylation reactions can be repeated, at least twice, achieving similar levels of phosphate esterified or hydrolyzed. The coordination of these two enzyme systems might play a role in some of the functions attributed to the protein kinase system.

Erythrocyte Membrane↗
PubMed1980

Endogenous phosphorylation of soluble enzymes in human red cells. Cyclic 3',5'-AMP-dependent phosphorylation of phosphofructokinase without detectable regulatory effect.

ATP-depleted human red cells have been incubated in a glucose-containing medium with [32P]orthophosphate in the presence and in the absence of cyclic 3',5'-AMP and dibutyril cyclic 3',5'-AMP. Spectrin, pyruvate kinase, phosphofructokinase, glucose-6-phosphate dehydrogenase and hemoglobin A1 have been purified and analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis. Protein-bound radioactivity has been measured from the sodium dodecyl sulfate polyacrylamide gels and the trichloroacetic acid-precipitated proteins. In the cytosol, the most intense phosphorylation was found for pyruvate kinase whose, in the presence of cyclic AMP, specific radioactivity was comparable to that of the membrane protein and spectrin. In the absence of cyclic nucleotides it was five times less phosphorylated. Phosphofructokinase was only phosphorylated when the red cells were incubated with cyclic nucleotides; the extent of phosphorylation was four times less than for pyruvate kinase. Hemoglobin, glucose-6-phosphate dehydrogenase and a contaminant protein copurified with phosphofructokinase were not phosphorylated: the 'background' of the radioactivity found for these proteins was 100 times less than for pyruvate kinase and spectrin, and 20 times less than for phosphofructokinase (+cyclic AMP).

Cyclic AMP↗
PubMed1980

Enzymatic analysis and collagen content in endomyocardial biopsy samples of patients with congestive cardiomyopathy of unknown etiology.

Endomyocardial biopsy samples from patients suffering from congestive cardiomyopathy of unknown etiology (COCM) were analyzed for lactate dehydrogenase (LDH) isoenzyme distribution by microisoelectric focusing. In addition, the concentration of collagen in the biopsy samples was estimated by determination of hydroxyproline and proline. The results were correlated with the clinical and hemodynamic data of the patients. Increased activities of total LDH and LDH5--the worse the hemodynamic parameters, the higher the concentration of LDH5--indicate an enhanced anaerobic glycolysis in the myocardium of COCM patients. The close correlation between the hemodynamic data and the LDH isoenzyme pattern suggests an association between severity of COCM and impairment of aerobic metabolism. The results of the alteration in the LDH isoenzyme pattern were not influenced by the collagen content in the myocardial biopsy samples. Varying isoenzyme patterns in the different parts and wall layers of the normal heart show the necessity of analyzing biopsy samples only from comparable localizations.

Biopsy↗
PubMed1980

Purification and characterisation of an unusually heat-stable and acid/base-stable class I fructose-1,6-bisphosphate aldolase from Staphylococcus aureus.

The fructose-1,6-biphosphate aldolase (EC 4.1.2.13) from Staphylococcus aureus ATCC 12 600 was purified and biochemically investigated. It was found that this aldolase belongs to the class I type of aldolases since the fructose-1,6-bisphosphate cleavage activity was insensitivity to high levels of EDTA. Like class I aldolases of higher organisms, the S. aureus aldolase activity is inhibited on incubation with the substrate dihydroxyacetone-phosphate in the presence of NaBH4. Furthermore, the aldolase activity is not stimulated by monovalent or divalent cations. This enzyme exhibits an extreme stability to high temperature, acid and base. The purified enzyme is not activated after heating at 97 degrees C for 1.6 h. An incubation at 130 degrees C for 10 min is necessary to destroy irreversibly the activity of the aldolase. The optimal temperature for activity, however, is 37 degrees C. It is a monomer with a molecular weight of about 33,000 and exhibits a relatively broad pH optimum ranging over pH 7.5-9.0. Apart from fructose 1,6-bisphosphate as substrate (Km = 0.045 mM), this aldolase also revealed activity with fructose 1-phosphate (Km = 25 mM). The pH of the isoelectric point lies between 3.95 and 4.25.

Chelating Agents↗
PubMed1980

Changes in the patterns of collagens and fibronectin during limb-bud chondrogenesis.

The distribution and sequence of appearance of fibronectin and of type-I and type-II collagen in the developing cartilage models of embryonic chick hind-limb buds was studied by immunofluorescence, using specific antibodies directed against these proteins. Fibronectin and type-I collagen are evenly distributed throughout the intercellular space of the mesenchyme prior to condensation of core mesenchyme of the limb anlage and formation of the cartilage blastema. With the onset of the condensation process fibronectin and type-I collagen appear to increase in the cartilage blastema compared to the surrounding loose mesenchyme, reaching a maximal density at the time of cartilage differentiation. The latter process is marked by the appearance of type-II collagen in the cartilage blastema. As cartilage differentiation progresses, type-I collagen is gradually replaced by type-II collagen; fibronectin disappears and is completely absent from mature cartilage. The transient appearance of type-I collagen and fibronectin suggests a temporal role in cell-matrix or cell-cell interactions in chondrogenesis, since it had been shown that (a) type-I collagen substrates stimulate cell proliferation and cartilage differentiation in limb-bud mesenchyme cell cultures; (b) fibronectin mediates attachment of cells to collagen substrates; and (c) fibronectin is directly involved in cellular interactions in chondrocyte cultures.

Animals↗