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Biomedical subjects

W Blum

Publications and source records attributed to W Blum.

50 records · Page 3Linked to original sources

Growth hormone induced rise in glomerular filtration rate is not obliterated by angiotensin-converting enzyme inhibitors.

In 8 healthy normotensive probands with normal glomerular filtration rate, the effect of recombinant human growth hormone (rhGH) on inulin clearance (Cin) was examined in an open study with intraindividual crossover with or without enalapril pretreatment (20 mg/day). rhGH was administered by subcutaneous injection (4.5 U twice daly) for 3 days. On the following day Cin was measured with an enzymatic steady state infusion technique. Systemic hemodynamics and potential metabolic effects of rhGH, i.e., inulin-like growth factors I and II, somatomedin-binding protein, glucagon, C peptide, amino acid pattern, etc., were monitored. On controlled dietary intake of protein, the median Cin rose 72 h after start of rhGh administration from 114 (range 91-158) to 135 (108-167) ml/min/1.73 m2 without enalapril pretreatment (p less than 0.01) and from 111 (88-153) to 131 (100-173 ml/min/1.73 m2 with enalapril pretreatment (p less than 0.02). The results confirm that (1) rhGH increases Cin to a similar extent as extractive GH and (2) further demonstrate that this action is not obliterated by blocking the circulating converting enzyme.

Adult↗

Improvement of uremic growth failure by recombinant human growth hormone.

Nine stunted prepubertal children with end-stage renal failure were treated by rhGH in supraphysiological doses (4 U/m2/day s.c.) for a period of six to nine months. The six-month data from these children indicated that exogenous rhGH significantly improved the growth rate in all children (mean height velocity SDS before therapy, -2.8; during the treatment period, +2.5). This effect was accompanied by a significant increase in serum somatomedin bioactivity. Low normal basal serum IGF I concentrations were increased by rhGH. Elevated basal serum IGF II concentrations were further increased by rhGH treatment. The pharmacokinetic profile of rhGH in uremia resembles that of the non-uremic state; no accumulation was seen after 14 days of treatment. Glucose tolerance did not change, and insulin levels remained stable throughout the six-month observation period. No rhGH antibodies were detected. Although these short-term results are very encouraging, the effects of rhGH on the prognosis for final height need to be assessed over a longer period of time.

Child↗

Identification of GTP-binding proteins in the plasma membrane of higher plants.

Antisera raised against a highly conserved amino acid sequence (G alpha-common peptide) of animal Gs alpha, Gi alpha, Go alpha and Gt alpha recognize, in plasma membranes of several higher plants, sets of proteins of Mr = 37 and 31 kDa (Vicia faba), 36 and 31 kDa (Arabidopsis thaliana) and 38 and 34 kDa (Commelina communis). The A. thaliana proteins were solubilized and partially purified. They bind [35S]GTP gamma S with high affinity (apparent Kd approximately 10 nM) and, with lower affinity, GTP but not the other nucleotides tested (ATP, CTP, ITP, UTP).

Blotting, Western↗

Direct stereochemical assignment of sugar subunits in naturally occurring glycosides by low energy collision induced dissociation. Application to papulacandin antibiotics.

A tandem mass spectrometric method is described which allows the assignment of stereochemistry to fragment ions comprising intact sugar subunits of larger glycosides without chemical degradation and product isolation by chromatography. The approach relies on the mass selection of the 'sugar ion' of interest followed by analysis of stereoselective fragmentation induced by low-energy collisional activation. The daughter ion spectra provide configurational fingerprints of the selected sugar ions which can be matched for identity with reference spectra obtained from suitable precursors of known stereochemistry. Glucose, mannose and galactose furnished the required set of the most important reference ions. By using peracetyl (and perdeuterioacetyl) derivatives, galactose was readily identified as the glycosidic sugar constituent of the (known) antibiotic papulacandin B and a further (unknown) congener.

Aminoglycosides↗

Characterization of the protein which binds insulin-like growth factor in human serum.

The binding of the 125I-labelled insulin-like growth factors I and II (125I-IGF I and 125I-IGF II) to the high-molecular-mass binding protein of human serum was characterized. With diluted human serum both growth factors showed optimal specific binding at 4 degrees C and pH 5-6. When 0.1% Triton X-100 was present in the incubation buffer an increase in the affinity of the IGF-binding protein was induced, which produced an enhanced binding of IGF I and IGF II. Competition experiments with various peptide hormones revealed that the native IGF-binding protein complex binds both the IGF I and IGF II with high specificity. Analysis of binding data according to the method of Scatchard resulted in linear plots for IGF I and IGF II respectively, indicating that in human serum only a single class of non-interacting binding sites is present. At optimal binding conditions the dissociation constants were determined to be 0.28 x 10(-9) M for IGF I binding and 0.66 x 10(-9) M for IGF II. Human serum was gel-filtered on Sepharose CL-6B at neutral pH and the eluate was assayed for binding activity with both IGF I and IGF II. One peak with an apparent molecular mass of 175 kDa and a Stokes radius of 4.8 nm was determined for both growth factors. Thus, our data suggest that human serum contains one class of high-molecular-mass binding protein with comparable binding characteristics for IGF I and IGF II.

Binding Sites↗

[Somatomedins].

Somatomedins are peptide hormones with insulin-like structure and effects. Their synthesis is governed by growth hormone. Somatomedins stimulate growth of cartilage tissue and other tissues. Synthesis of somatomedins occurs in various tissues, predominantly in the liver. For clinical practice determinations of somatomedin C (= IGF I) levels in blood have become valuable, since they give insights into the growth hormone secretory state, being low in growth hormone deficiency and high in acromegaly. In other growth disorders somatomedin C measurements can give new insights into the underlying pathogenesis. The role of IGF II and other peptides with somatomedin-like characteristics is presently under investigation.

Acromegaly↗

[Training effects in the treatment of neuroses].

The whole kinetotherapeutic programme of a psychotherapeutic department--without systematic training in the sense of athletics--in more than half of the cases surprisingly leads to physiologic changes, as they are to be expected in a submaximal training. In significant correlation with this the quality of the rule of the circulatory parameter investigated (pulse rate) improves. In the majority of cases in which positive training and regulation effects developed the psychotherapeutic results were clearly positive, too. On the other hand only in less than half of all cases with clear psychotherapeutic improvement training effects could be proved. The psychologic effects of training are based on a reaction complex the most essential components of which are described.

Conditioning, Psychological↗

In vivo and in vitro phosphorylation of DNA-dependent RNA polymerase of Escherichia coli by bacteriophage-T7-induced protein kinase.

After infection with bacteriophage T7 the beta' and to a lesser extent the beta subunits of E. coli DNA-dependent RNA polymerase (nucleosidetriphosphate:RNA nucleotidyltransferase, EC 2.7.7.6) are phosphorylated by a phage-gene-encoded protein kinase (ATP:protein phosphotransferase, EC 2.7.1.37). The phosphorylation occurs on threonine residues and appears site-specific. It is probably the molecular basis of the early transcriptional control.

Coliphages↗