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Biomedical subjects

M Strauch

Publications and source records attributed to M Strauch.

At least 37 records · Page 2Linked to original sources

Washing erythrocytes to remove interferents in measurements of zinc protoporphyrin by front-face hematofluorometry.

Zinc protoporphyrin (ZPP) is determined by hematofluorometry of whole blood to detect iron deficiency in blood donors. In hospitalized patients, ZPP did not correlate with established markers of iron status. We performed 4500 ZPP measurements with the Aviv front-face hematofluorometer in samples from 475 patients and measured ferritin, transferrin saturation, hemoglobin, and erythrocyte indices. We found that the fluorometric determination is affected by substances dissolved in plasma but that this interference can be eliminated by using washed erythrocytes. In validation tests the within-day variation was < 3.5%; the day-to-day variation was < 6.8%. In 130 healthy persons without iron deficiency, ZPP was < or = 40 mumol/mol heme, which we consider a normal value. Mean ZPP in 46 iron-deficient patients was 256 (SD 105) mumol/mol heme (correlation with ferritin: -0.73; with hemoglobin: -0.85; P < 0.001). When washed erythrocytes are used, the hematofluorometric determination of ZPP is sensitive and specific for detecting iron deficiency in otherwise healthy individuals and hospitalized patients.

Blood Donors↗

Effect of low-protein diet on renal function: are there definite conclusions from adult studies?

Low-protein diets have been used for roughly a century in order to alleviate uraemic symptoms and to delay progression of chronic renal failure (CRF). Currently a number of different low-protein diets are used, supplying either 0.6 g protein/kg body weight or 0.3-0.4 g supplemented with amino-acids or keto-acids. Single centre trials have attempted to demonstrate the efficacy of these diets in slowing down the progression of CRF. The results from these trials are, however, sometimes inconclusive, showing either a high efficiency of the low-protein diet or no efficiency at all. Conclusive data from multicentre trials, however, are not yet available. A crucial point in analysing the efficacy of low-protein diets is the degree of compliance with the protein restriction. Today, the data available indicate that sometimes only a poor degree of compliance is achieved both in single and in multicentre trials.

Dietary Proteins↗

The SpoOA protein of Bacillus subtilis is a repressor of the abrB gene.

The spoOA gene of Bacillus subtilis is critical for the initial stages in the developmental cycle leading to the formation of an endospore. We show that one function of the SpoOA protein is to negatively regulate another regulatory locus, abrB, which controls the expression of many genes associated with the onset of sporulation. Purified SpoOA protein binds to a specific region of the abrB promoter and functions as a repressor of transcription in an in vitro assay. The binding of the SpoOA protein is independent of the binding of the AbrB protein, which is known to autoregulate its expression. This independence mirrors the temporal sequence of events in abrB control.

Bacillus subtilis↗

A low-protein diet protects uremic rats against the negative sequelae of metabolic acidosis.

Metabolic acidosis is a common finding in uremia. The metabolic consequences, however, are poorly understood. Thus, the aim of our study was to assess the effect of chronic metabolic acidosis in 5/6-nephrectomized male Sprague-Dawley rats given a normal (18%; n = 19) and a low-protein diet (8%; n = 23). Each of these groups was sequentially given CaCO3 and CaCl2 in the drinking water for a fortnight each. The animals were randomly assigned to start either with CaCO3 or CaCl2 (random cross-over design). The blood pH decreased significantly in both CaCl2 groups (18% protein: CaCO3 7.18 vs. CaCl2 7.11; 8% protein: CaCO3 7.26 vs. CaCl2 7.09) as did standardized base excess (18% protein: CaCO3-5.9 vs. CaCl2-9.7; 8% protein: CaCO3-3.6 vs. CaCl2-12.6). Food intake declined during acidosis in both groups, but more in the 18% protein group. The same occurred with body weight (g) in the 18% group, which decreased dramatically (8% protein: CaCO3 389 vs. CaCl2 390; 18% protein: CaCO3 413 vs. CaCl2 366). The change in body weight was reflected in the urinary urea excretion (mg/24 h/g food) (8% protein: CaCO3 0.9 vs. CaCl2 1.0; 18% protein: CaCO3 2.2 vs. CaCl2 30.8). There was a significant increase in proteinuria (mg/24 h) in the 8% group (CaCO3 10 vs. CaCl2 15), while in the 18% group no real change occurred (CaCO3 24 vs. CaCl2 18). Factoring the proteinuria for food intake, however, also resulted in a tendency towards an increased proteinuria in the 18% group.(ABSTRACT TRUNCATED AT 250 WORDS)

Acidosis, Renal Tubular↗

Rate of deterioration of renal function in juvenile nephronophthisis.

The rate of deterioration of renal function was determined in 29 patients with juvenile nephronophthisis presenting before the age of 18.5 years. The analysis was based on 618 serial determinations of serum creatinine (SCR). By application of a new statistical method the time elapsing between different successive SCR levels was calculated. A more or less homogeneous increase of SCR was noted starting from the time when a SCR of 4 mg/dl was reached. The median time elapsing between an SCR of 2 and 4 mg/dl was 32 months, between 4 and 6 mg/dl 10 months and between 6 and 8 mg/dl 5 months. The median age at the start of renal replacement therapy or death due to uraemia, evaluated by survival analysis, was similar in both sexes.

Adolescent↗

Is gender a determinant for evolution of renal failure? A study in autosomal dominant polycystic kidney disease.

More males than females enter renal replacement therapy programs. This may reflect greater propensity of men to acquire renal disease, faster progression of renal disease, or a combination of both. In order to address this problem, autosomal dominant polycystic kidney disease (ADPKD), a well-defined genetically homogenous hereditary disorder, was studied. One hundred fifty-eight cases of the disease in adults were diagnosed by sonography and studied (73 men, 85 women); 58 of the patients had reached end-stage renal failure. Survival analysis of age at renal death revealed a significant gender difference (log-rank test, P = 0.0072): median age at renal death was 52.5 years in men and 58.0 years in women. In 64 patients with adequate sequential measurements of serum creatinine, progression of renal failure was followed retrospectively. When serum creatinine was greater than 3 mg/dL, the average rate of progression was similar in both sexes. In contrast to ADPKD, a sex difference for the age at renal death was not found in prepubertal individuals with hereditary renal diseases, ie, cystinosis or nephronophthisis. The data suggest that sex (hormones) influences evolution of renal failure.

Creatinine↗

Negative Haemoccult test in malignant and premalignant lesions of the colon. Validation of the Haemoccult test with total colonoscopy.

To date, no published report on a trial has provided sufficiently strong evidence of the accuracy of the Haemoccult Test assessed by false-negative error, and validated on the basis of a complete colonoscopy of all patients. Total colonoscopy (up to the cecum) was performed on 534 patients whose stools had been tested for occult blood. The results of the colonoscopy were classified as follows: --expected continual bleeding (target lesions: carcinoma, polyps greater than or equal to 10 mm) --intermittant bleeding (polyps less than 10 mm, colitis, etc.), and --no source of bleeding. Results were regarded as false-negative in patients who were found to have a target lesion (carcinoma, polyp greater than or equal to 10 mm) following a negative Haemoccult test. Apart from positive and negative prognostic values, sensitivity and specificity were taken into account as characteristics for the quality of the test. Following a positive Haemoccult test result 46 of the 534 patients were found to have polyps greater than or equal to 10 mm and 22 carcinomas; following negative Haemoccult test results 31 patients were found to have polyps measuring greater than or equal to 10 mm in diameter and 2 carcinomas. On the basis of the chosen classification a false-negative Haemoccult result was established in 8.6% and a false-positive result in 4.3%. The Haemoccult test showed a sensitivity of 67% and a specificity of 93% in patients with target lesions or patients without a source of bleeding.

Colonoscopy↗

Glutamine auxotrophs of Bacillus subtilis that overproduce glutamine synthetase antigen have altered conserved amino acids in or near the active site.

A number of mutations within the Bacillus subtilis glutamine synthetase (GS) gene result in altered catalytic properties and overproduction of the GS antigen. The restriction fragments containing mutations from three such mutants were sequenced, and they all had amino acid changes in conserved residues found either within or near sequences contributing to the active site of the Salmonella typhimurium GS.

Amino Acid Sequence↗

Does a low protein diet really slow down the rate of progression of chronic renal failure?

In this paper we present evidence from data obtained by different study groups, indicating that a low protein diet slows down the rate of progression of chronic renal failure. These data also demonstrate that the delay of progression is highly dependent on the underlying renal disease. In absolute terms, patients suffering from polycystic kidney disease experienced most benefit from a low protein diet, while in relative terms, the natural course of the renal disease of patients suffering from chronic glomerulonephritis is significantly more delayed than in other disease groups. Furthermore, a vegetarian diet seems to be superior to a meat-containing diet. Thus, we conclude that there are sufficient data from the literature to suggest that a low protein diet delays the progression of chronic renal failure.

Amino Acids↗