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M H Weber

Publications and source records attributed to M H Weber.

At least 19 recordsLinked to original sources
PubMed1999

Cold shock response of Bacillus subtilis: isoleucine-dependent switch in the fatty acid branching pattern for membrane adaptation to low temperatures.

Bacillus subtilis has developed sophisticated mechanisms to withstand fluctuations in temperature. Membrane fatty acids are the major determinants for a sufficiently fluid membrane state to ensure the membrane's function at all temperatures. The fatty acid profile of B. subtilis is characterized by a high content of branched fatty acids irrespective of the growth medium. Here, we report on the importance of isoleucine for B. subtilis to survive cold shock from 37 to 15 degrees C. Cold shock experiments with strain JH642 revealed a cold-protective function for all intermediates of anteiso-branched fatty acid biosynthesis. Metabolites related to iso-branched or straight-chain fatty acid biosynthesis were not protective. Fatty acid profiles of different B. subtilis wild-type strains proved the altered branching pattern by an increase in the anteiso-branched fatty acid content and a concomitant decrease of iso-branched species during cold shock. There were no significant changes in the fatty acid saturation or acyl chain length. The cold-sensitive phenotype of isoleucine-deficient strains in the absence of isoleucine correlated with their inability to synthesize more anteiso-branched fatty acids, as shown by the fatty acid profile. The switch to a fatty acid profile dominated by anteiso-C(15:0) and C(17:0) at low temperatures and the cold-sensitive phenotype of isoleucine-deficient strains in the absence of isoleucine focused our attention on the critical role of anteiso-branched fatty acids in the growth of B. subtilis in the cold.

Adaptation, Physiological↗
PubMed1997

[Microproteinuria and enzymuria in fever and pyelonephritis in childhood. A prospective study of 180 children].

In 180 children (87 children belonging to a control group, 68 with fever of non-renal origin, and 25 with pyelonephritis) albumin and immunoglobulin G (markers for glomerular dysfunction), alpha-1-microglobulin and beta-NAG (markers for proximal tubular dysfunction) and apolipoprotein A1 (marker of "postrenal' dysfunction) were measured in second-voided morning urine. In children with fever of non-renal origin, glomerular dysfunction was encountered in 8.8%, tubular dysfunction in 17.6% and mixed glomerular-tubular dysfunction in 14.7% of cases. Among children with pyelonephritis, 28% revealed glomerular dysfunction and 44% mixed glomerular-tubular dysfunction. No case of solitary proximal tubular dysfunction was observed in children with pyelonephritis. There were highly significant differences in presence and expression of glomerular dysfunction between children with fever of non-renal origin and children with pyelonephritis (P < 0.0001), whereas with regard to proximal tubular dysfunction, the differences were only moderately significant (beta-NAG: P < 0.01) or of low significance (alpha-1-microglobulin: P < 0.05). This may indicate that morphologic changes occur during interstitial pyelonephritis due to inflammation of glomeruli, resulting in glomerular dysfunction, while proximal tubular dysfunction may additionally be due to fever-associated function processes.

Acetylglucosaminidase↗
PubMed1997

A family of cold shock proteins in Bacillus subtilis is essential for cellular growth and for efficient protein synthesis at optimal and low temperatures.

Like other bacteria, Bacillus subtilis possesses a family of homologous small acidic proteins (CspB, CspC and CspD, identity >70%) that are strongly induced in response to cold shock. We show that deletion of cspC or cspD genes did not result in a detectable phenotype; in contrast, csp double mutants exhibited severe reduction in cellular growth at 15 degrees C as well as at 37 degrees C, including impairment of survival during the stationary phase. Two-dimensional gel analysis showed that protein synthesis was deregulated in csp double mutants and that the loss of one or two CSPs led to an increase in the synthesis of the remaining CSP(s) at 37 degrees C and after cold shock, suggesting that CSPs down-regulate production of members from this protein family. A cspB/C/D triple mutant (64BCDbt) could only be generated in the presence of cspB in trans on a plasmid that was not lost, in spite of lack of antibiotic pressure, indicating that a minimum of one csp gene is essential for viability of B. subtilis. After cold shock, synthesis of CspB in 64BCDbt was drastically lower than in wild-type cells accompanied by cessation in growth and strong reduction in general protein synthesis. As CspB, CspC and CspD are shown to bind to RNA in a co-operative and interactive manner, CSPs are suggested to function as RNA chaperones facilitating the initiation of translation under optimal and low temperatures.

Bacillus subtilis↗
PubMed1996

[Polyarticular gout--change in the clinical picture?].

40% of the male patients suffering from gouty arthritis treated in our rheumatological unit during a three years period showed a chronic polyarticular course. In polyarticular gout, acute gouty attacks affect above all the joints of the upper limbs. Gouty arthritis in these patients shows an ascending pattern. Therefore, in case of unawareness of the clinical symptoms, differential diagnosis can be difficult especially when laboratory findings including uric acid levels are in normal ranges and classical radiological findings are missing. It is important to notice that the atypical joint attack in gouty arthritis is typical for polyarticular gout. In case of unclear arthritis the polarized light microscopy of the synovial fluid should always be demanded.

Adult↗
PubMed1995

Effects of various HTK solution regimens on proteinuria after renal transplantation in dogs.

Investigations were carried out by means of an autologous, heterotopic model for kidney transplantation applied to dogs. Duration of cold ischemia was 48 h. Four experimental groups were arranged. During the first 20 min following revitalization of the transplanted kidney, group 1 (HTK solution/80 cm perfusion height) showed a significant glomerular and tubular malfunction. In group 2 (HTK solution/120 cm perfusion height), only four urinary proteins with molecular weights of 25 kDa, 67 kDa, 100 kDa and > 100 kDa were found. The excretion of higher molecular proteins receded over the 20-min period of observation. In both group 3 (HTK/aspartate solution) and group 4 (HTK/tryptophan solution) the quantity of excreted glomerular and tubular protein was well above that of group 2. As opposed to the "Tryptophan" group, a complete restoration of renal function was observed in the "Aspartate" group after 4 weeks. In general, the "standard" HTK protective solution delivered with 120 cm perfusion pressure gave the most favorable results, with the lowest levels of proteinuria and a satisfactory recovery of renal function after revitalization.

Albuminuria↗
PubMed1993

Prenatal diagnosis of congenital nephrosis of the Finnish type (CNF) in the second trimester.

Congenital nephrosis of the Finnish type is an hereditary, autosomal recessive disease which leads to death in early infancy. This is a case report concerning an affected fetus with legal interruption in the 24th week of gestation on the basis of certain sonographic changes in the fetal kidneys and changes in the protein profile in amniotic fluid, which were consistent with nephrotic damage of the kidneys. Light and electron microscopy showed evidence of CNF, i.e. increase of mesangial matrix and cells in glomeruli, dilated tubular segments, and effaced and plumb foot-processes of the glomerular epithelial cells. Antenatal diagnosis of CNF therefore seems feasible in the second trimester of gestation by means of AFP determinations in maternal serum and amniotic fluid as well as by using sonographic criteria and determination of proteins in amniotic fluid.

Amniotic Fluid↗
PubMed1992

[Imaging and functional parameters in diagnosis of obstructive nephropathy].

Obstruction of the kidney leads to terminal kidney failure within a few years. Therefore, early recognition of such obstruction is of importance. Non-invasive diagnostic ultrasound examination now allows intrauterine visualization of a suspected obstruction. However, the implications of such a dilated ureteral pelvic system are obscure. Whether there is obstruction or dilatation can only be evaluated postnatally by a nuclear technique. The aim of our study was to measure the recovery of kidney function. We investigated 13 kidneys of 9 newborns or small infants (up to 2 years). The follow-up was continuous for up to 29 days. The parameters were: urine output (24-h clearance), glomerular filtration rate, fractional excretion of sodium and potassium, free water clearance, total protein excretion, albumin and alpha 1 microglobulin excretion. The urine output fell from 0.3 to 0.12 ml/min within 14 days after relief of obstruction. The glomerular filtration rate rose from nearly 30 ml/min to about 50 ml/min within a week. The fractional excretion of sodium and potassium indicated recovery of the proximal tubli. The fractional sodium excretion fell below 1% within 4 days. The free water clearance reflects the concentrating ability of the kidney, and in kidneys from newborns it had only positive values, while in kidneys of children older than 6 months there were also negative values. The protein excretion and the albuminuria showed recovery of the glomerular as well as the tubular system.(ABSTRACT TRUNCATED AT 250 WORDS)

Alpha-Globulins↗
PubMed1992

Alpha 1-microglobulin (protein HC): features of a promising indicator of proximal tubular dysfunction.

alpha 1-Microglobulin (protein HC) is a stable urinary indicator protein which reflects acute and chronic dysfunctions of the proximal renal tubule. High urinary concentrations were found to be indicative of tubular drug toxicity, interstitial nephritis or chronic renal failure. The protein is synthesized by liver cells and readily associates with serum immunoglobulin A. Only the free form is filtered through the glomerulus and is reabsorbed by proximal tubular cells. The exact physiological function of this member of the new superfamily of lipocalins is still unknown, but there are indications that alpha 1-microglobulin (protein HC) may serve as an excretion vehicle for fluorescent, charge-heterogeneous substances of unknown nature. Additionally, it seems to be associated with the humoral and cellular immune response.

Alpha-Globulins↗
PubMed1991

Rapid increases in the membrane expression of neutral endopeptidase (CD10), aminopeptidase N (CD13), tyrosine phosphatase (CD45), and Fc gamma-RIII (CD16) upon stimulation of human peripheral leukocytes with human C5a.

Rapid increases in the membrane expression of C3 receptors on granulocytes and monocytes in response to the anaphylatoxin C5a have previously been described. In this study we demonstrate increases in the membrane expression of neutral endopeptidase (NEP, CD10, CALLA), aminopeptidase N (APN, CD13), tyrosine phosphatase (CD45/CD45Ro) and the Fc R Fc gamma-RIII (CD16) on granulocytes within minutes of treatment with human C5a. Monocytes responded to C5a with increases in CD13 and CD45/CD45Ro. These membrane modulations could be prevented by preincubating the C5a preparations with anti-C5a mAb C17/5 but not by pretreating the cells with cycloheximide. Increases of CD10, CD13, and CD11b but not CD11a (LFA-1) were also observed in leukocytes from patients undergoing hemodialysis with cuprophan membranes. The increase of CD16 on granulocytes was dependent on the presence of plasma during in vitro activation with C5a indicating that plasma contains inhibitors which prevent the previously described loss of Fc gamma-RIII upon stimulation of the cells.

Aminopeptidases↗
PubMed1991

Elevated plasma levels of the immunosuppressive complement fragment Ba in renal failure.

The complement fragment Ba is a 33 kD activation product of factor B which suppresses human B-lymphocyte functions in vitro. We report that plasma levels of Ba are highly elevated in patients with chronic renal failure (4.84 +/- 3.58 micrograms/ml) and in patients with end-stage renal disease undergoing regular hemodialysis (16.1 +/- 6.1 micrograms/ml) as compared to normals (1.01 +/- 0.30 micrograms/ml). Ba levels were strictly correlated with the creatinine clearance. The urinary excretion of Ba was 165-fold higher in patients with tubular proteinuria than in normals. These results indicate that the kidney is the major catabolic site for Ba. In addition, direct evidence was obtained for an enhanced turnover of the alternative pathway of complement in renal failure that, although it appears to be less important than the renal retention of Ba, contributes to elevated Ba plasma levels in these patients. Ba concentrations in dialysis patients who responded to hepatitis B vaccination were significantly lower than in non-responders. Furthermore, the in vitro IgM synthesis by purified mononuclear cells was negatively correlated with Ba concentrations determined in the plasma of these patients. These results suggest that the accumulation of Ba contributes to the defective immune response in patients with renal failure.

Adult↗
PubMed1991

[Localization and extent of tissue damage caused by extracorporeal lithotripsy (ESWL)].

Extracorporeal shock wave lithotripsy (ESWL) causes proteinuria. In our study we investigated the protein fractions and the electrolyte composition of the urine in patients who had been treated with ESWL. The aim was to obtain information on the degree and the localisation of the glomerular, tubular or vascular destruction caused by ESWL in humans. A total of 34 patients with stones had been treated with ESWL. As parameters we used: urine output, creatinine clearance, total protein, albumin, immunoglobulin G, N-acetyl-beta-D-glucosaminidase (beta-NAG), alpha-1-microglobulin, the fractional excretion of Na+ and apolipoprotein-A-1. After ESWL treatment proteinuria and albuminuria are found. Our parameters show no deterioration of the glomerula or the tubulus. The increase in apolipoprotein-A-1, a postglomerular parameter, however, is interpreted as a manifestation of vascular destruction after ESWL; this is normally temporary, leaving no permanent damage.

Acetylglucosaminidase↗
PubMed1990

[Plasma endothelin in normal probands and patients with nephrologic-rheumatologic and cardiovascular diseases].

Plasma concentrations of the recently isolated potent vasoconstrictory peptide endothelin were measured in 382 patients. The investigations were performed by means of a sensitive radioimmunoassay specific for Endothelin-1, 2. The results from 110 healthy volunteers displayed a normal range of 44.67 +/- 3.51 pg/ml. Significantly raised levels were found in 33 patients with chronic end-stage renal failure both before and after hemodialysis. In contrast, 35 patients with compensated renal insufficiency did not differ from the normals. Sixty-five patients after kidney transplantation revealed significantly elevated levels, as did 27 patients with acute myocardial infarction, 8 after coronary bypass surgery, and 5 with liver cirrhosis. The mean values of 27 patients with untreated hypertension, 22 with secondary hypertension, of various causes and 16 with coronary artery disease were comparable to the normal population. The values were significantly decreased in 9 pregnant women with hypertension and proteinuria. A marked decline was found in 5 patients with systemic lupus erythematodes, while 20 patients with rheumatoid arthritis demonstrated only a slight decrease. The pathophysiological role of endothelin as a local or circulating hormone in regulating systemic blood pressure or release of other hormones remains to be determined.

Arthritis, Rheumatoid↗
PubMed1989

Urinary protein electrophoresis profile in normal and hypertensive pregnancies.

By using of modified urine preparation and a highly sensitive SDS-polyacrylamide gel electrophoresis (SDS-PAGE) we determined the urinary protein profile in 21 healthy males, 25 healthy females, 64 patients with uncomplicated pregnancy and 110 hypertensive pregnant women. The urinary protein patterns were similar in controls and in women with a normal pregnancy. There were no increase in the number of protein bands from the 1st trimester to term, and the electrophoresis pattern did not change in the postpartum period. In both groups, an intensively stained protein band with an apparent molecular weight of 105 kD was detected. The 105 kD band was significantly reduced or completely absent in 91 (83%) out of 110 hypertensive pregnant women. The urinary protein electrophoresis profile correlated significantly with the severity of the disease. The 105 kD band disappeared just before or simultaneously with the onset of clinical symptoms in 18 out of 32 hypertensive pregnant women followed throughout pregnancy. Postpartum the 105 kD in urine reappeared at 2 to 14 days after delivery in 49 of the 53 patients. Using a silver staining and Western blot, the 105 kD band was identified as Tamm-Horsfall protein, which is identical to the immunosuppressive glycoprotein uromodulin. The findings in the SDS-PAGE may reflect a transitory tubular dysfunction in cases of pre-eclampsia, which is usually reversible after delivery. The results of our study support the hypothesis of an immunological basis for this disorder.

Adolescent↗
PubMed1989

Influence of CAPD and residual diuresis on the serum levels of alpha-1-microglobulin in end-stage renal disease.

The chronic retention of proteins of low molecular weight (LMWP) seems to be connected with some unsolved problems of end-stage renal disease (e.g. reduced immune function, AB amyloidosis, hormonal imbalances), irrespective of the type of renal replacement therapy. Therefore, several recently discovered LMWPs such as alpha 1-microglobulin have to be evaluated concerning their contribution to the uremic syndrome. Although we observed a considerable daily loss of total protein into the CAPD dialysate, no differences were found in the removal of small proteins (MW less than 68 kilodaltons) when compared to conventional hemodialysis. Maintenance of renal function (residual diuresis greater than 100 ml/day) seems to be more potent keeping the serum concentrations of LMWP low than CAPD or hemodialysis.

Adult↗