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Biomedical subjects

K Blau

Publications and source records attributed to K Blau.

At least 19 recordsLinked to original sources
PubMed1988

Killing of Brucella abortus by bovine serum.

Studies of the serum bactericidal system in bovine brucellosis were undertaken to investigate the role of the humoral immune response in protection of cattle against the facultative intracellular parasite Brucella abortus. Fresh sera from normal control cattle, infected cattle, and cattle immunized with B. abortus cell envelopes were collected before treatment and during the course of immunization or infection. Normal fresh bovine serum or fresh agammaglobulinemic serum from colostrum-deprived calves was effective in killing smooth virulent B. abortus 2308, but rough strains RB51 (a rough mutant of strain 2308) and 45/20 were much more sensitive to serum. The difference in susceptibility to serum was shown to be correlated with differences in lipopolysaccharide chemotype, with the more resistant strain 2308 having O polysaccharide and the more susceptible strains 45/20 and RB51 lacking O side chains. By treatment of fresh serum with MgCl2 and EGTA [ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid] killing was shown to occur via the classical pathway of complement activation. When antibody to B. abortus was present, killing of strain RB51 increased but killing of smooth strain 2308 decreased. The earliest antibody response in serum from infected animals did not interfere with killing. When affinity-purified bovine immunoglobulins specific for B. abortus smooth lipopolysaccharide were added to fresh normal bovine serum, immunoglobulin G1 (IgG1) and IgG2 isotypes blocked killing but IgM and IgA isotypes did not. Thus, it appears that serum from previously unexposed animals or animals early during infection can kill smooth B. abortus, an appropriate defense mechanism before the organism becomes intracellular. At later stages of infection, blocking antibodies predominate.

Animals↗
PubMed1985

Serum susceptibility of Haemophilus somnus from bovine clinical cases and carriers.

The serum susceptibility of 64 isolates of Haemophilus somnus from cattle was determined in a bactericidal assay with undiluted fresh or inactivated bovine serum with serial dilutions of bacterial suspension in RPMI 1640 medium. A total of 27 strains isolated from cattle with clinical disease (4 with thromboembolic meningoencephalitis, 13 with pneumonia, and 10 with reproductive failure) were compared with 35 strains from asymptomatic carriers (11 from the vagina and 24 from the prepuce). Essentially, all clinical isolates were serum resistant, whereas approximately 25% of preputial isolates were serum susceptible, as judged after 1 h of incubation in serum; a majority of vaginal isolates showed delayed serum susceptibility. Lysozyme played no role in serum killing, and the alternative complement pathway played only a minor role. Iron saturation, however, appeared to impart greater serum resistance to serum-susceptible strains from the vagina and prepuce. Perhaps the serum-susceptible strains from carriers would be useful vaccine candidates, but resistant strains from carriers may be pathogenic.

Animals↗
PubMed1983

Hyperphenylalaninemia with defective transamination.

Blood phenylalanine concentrations in a female neonate increased slowly to a level at which dietary phenylalanine restriction became necessary. At this point the patient's urinary aromatic acid excretion profile showed only minimal amounts of phenylpyruvic acid or related aromatic acids. Phenylalanine-tolerance tests, and a subsequent challenge with a normal diet for three days, revealed a progressive decline in the blood phenylalanine concentration at which transamination started to occur. This fits the classification of 'hyperphenylalaninemia with transamination defect'. Possible explanations for the defective metabolism are discussed in the light of the experimental findings.

Amino Acid Metabolism, Inborn Errors↗
PubMed1980

The analysis of hexitols in biological fluid by selected ion monitoring.

The development of a selected ion monitoring assay is described for the analysis of polyols as their per-acetyl derivatives, using L-iditol as an internal standard. Concentrations of mannitol, galactitol, sorbitol and inositol have been determined in the serum, urine and amniotic fluid from women during the second trimester of uncomplicated pregnancies. Two samples of amniotic fluid from galactosaemic pregnancies showed elevated levels of galactitol, 8.1 and 7.7 mu mol l-1 compared with normal concentrations of 0.46 +/- 0.26 mu mol l-1, whereas a normal homozygous pregnancy of heterozygous parents showed normal levels.

Amniotic Fluid↗
PubMed1979

Separation and quantification of urinary di- and polyamines by gas chromatography with electron capture detection.

A sensitive and specific gas chromatographic assay procedure employing electron capture detection has been developed for the assay of free and total di- and polyamines in human urine. Urine samples, hydrolysed with hydrochloric acid where necessary for the measurement of total amine output, were evaporated to dryness and, after the residues had been taken up in water, purified successively on Porapak Q and Dowex 50 X2 columns. Following evaporation of eluate, pentafluoropropionyl derivatives were made and analysed gas chromatographically using temperature programming. Di- and polyamines can be measured accurately at the picomole level and normal urinary output values calculated using this method agree well with those noted by other workers.

Chromatography, Gas↗
PubMed1979

Urinary phenylethylamine excretion: gas chromatographic assay with electron-capture detection of the pentafluorobenzoyl derivative.

Phenylethylamine was extracted into n-hexane from alkaline urine saturated with sodium chloride, and back-extracted into dilute acid. The extract was freeze-dried and the residue converted to a pentafluorobenzoyl derivative for analysis by gas chromatography on a column of OV-225 with electron-capture detection. Quantification was achieved by adding an internal standard of tolylethylamine to each sample prior to extraction. Output values in normal subjects and in some patients with phenylketonuria and hyperphenylalaninaemia were in agreement with those in some other recent reports.

Adult↗
PubMed1979

Tranylcypromine ('Parnate') overdose: measurement of tranylcypromine concentrations and MAO inhibitory activity and identification of amphetamines in plasma.

A case of tranylcypromine overdose is reported. Tranylcypromine, amphetamine methamphetamine and phenylethylamine were detected in the plasma by gas chromatography and their identity confirmed by mass spectrometry. The data suggested that the amphetamines were metabolic products of tranylcypromine. Platelet monoamine oxidase activity was more than 95% inhibited during the 72 h after the overdose despite complete clinical recovery by that time. The possible role of amphetamines and phenylethylamine in causing the clinical manifestations of tranylcypromine overdose is discussed.

Amphetamine↗
PubMed1978

Some problems of alpha-fetoprotein screening.

In two years of a routine screening programme for the detection of neural-tube defects over 6000 women had serum-alpha-fetoprotein (A.F.P.) measured. As a result, 80 women carrying live singleton fetuses were offered amniocentesis under ultrasound control. All neural-tube defects detected at birth were recorded and necropsies were done routinely on abortuses, thus permitting evaluation of the screening programme in terms of false negatives and false positives. 16 amniotic-fluid A.F.P.s were abnormal, 1 for an unaffected fetus; and 2 others were normal for fetuses which had closed lesions. At the serum-A.F.P. stage, 3 lesions were missed. The detection-rate compares favourably with those of other series. However, in a pilot study, routine ultrasonic assessment of gestation yielded a substantial proportion of cases where a serum-A.F.P. deemed normal or abnormal when gestation was assessed clinically would have been misleading. Loss of normal fetuses subsequent to amniocentesis (5 in this series) also has to be taken into account.

Abortion, Therapeutic↗
PubMed1978

An improved determination of total glycosaminoglycans in body fluids by formation of complexes with quinacrine: changes in amniotic fluid total glycosaminoglycans during normal pregnancies and in pregnancies at risk for mucopolysaccharidoses.

Acidic glycosaminoglycans form insoluble complexes with quinacrine and this has been exploited for their analysis in blood, urine and amniotic fluid. The method is specific for glycosaminoglycans including keratan sulphate and the samples do not have to be deproteinized. Values for normal urine, serum and amniotic fluid are presented. Urinary total glycosaminoglycans excreted by patients with mucopolysaccharidoses were also determined. The normal changes in amniotic fluid total glycosaminoglycans have been measured between 14 weeks' gestation and term, and values are given for amniotic fluid total glycosaminoglycans in several pregnancies at risk for mucopolysaccharidoses. It is suggested that this method is a potentially valuable analytical tool in the pre-natal diagnosis of mucopolysaccharidoses.

Amniotic Fluid↗
PubMed1978

Exocrine-gland function and the basic biochemical defect in cystic fibrosis.

A biochemical link is proposed between secretion and reabsorption in exocrine glands, in the form of a factor (kinin E) which initiates ion reabsorption. Activation of this factor involves arginine esterases, and in cystic fibrosis these may be defective, preventing the formation of kinin E. In cystic fibrosis stimulation of exocrine glands produces abnormal reabsorption of ions, leading to the physiological abnormalities and clinical manifestations of the disease.

Absorption↗
PubMed1978

A sensitive semi-automated kinetic assay of alpha-D-glucosidase for the prenatal diagnosis of type 2 glycogenosis (Pompe's disease).

Prenatal diagnosis of type 2 glycogenosis (Pompe's disease) has been done on cultured amniotic fluid cells, using a semi-automated fluorimetric kinetic assay for alpha-D-glucosidase with 4-methylumbelliferyl-alpha-D-glucoside as substrate. The activity of the enzyme was related to that of beta-D-galactosidase, and found to be absent in cells from an affected fetus. The diagnosis was confirmed in fetal liver, where the same assay was used to show absence of alpha-D-glucosidase activity with normal beta-D-galactosidase activity, and where increased glycogen deposition was demonstrated histologically. This type of assay is generally applicable to lysosomal enzymes, and to other fluorigenic enzyme reactions.

Amniocentesis↗