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Biomedical subjects

J Barr

Publications and source records attributed to J Barr.

At least 145 records · Page 8Linked to original sources
PubMed1985

Purification and partial characterization of alkaline phosphatase of matrix vesicles from fetal bovine epiphyseal cartilage. Purification by monoclonal antibody affinity chromatography.

Alkaline phosphatase of matrix vesicles isolated from fetal bovine epiphyseal cartilage was purified to apparent homogeneity using monoclonal antibody affinity chromatography. The enzyme from the butanol extract of matrix vesicles bound specifically to the immobilized antibody-Sepharose in the presence of 2% Tween 20 whereas the major portion of nonspecific protein was removed by this single step. Of various agents tested, 0.6 M 2-amino-2-methyl-1-propanol, pH 10.2, was the most effective in eluting 80-100% of the enzyme initially applied. Both Tween 20 and 2-amino-2-methyl-1-propanol associated with the eluted enzyme were effectively removed by the sequential application of DEAE-cellulose and Sepharose CL-6B chromatography. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the enzyme preparation treated with sodium dodecyl sulfate and mercaptoethanol showed the presence of a dominant band (using silver staining) corresponding to a molecular weight of 81,000. This molecular weight was nearer reported values for rat liver (Ohkubo, A., Langerman, N., and Kaplan, M. M. (1974) J. Biol Chem. 249, 7174-7180) and porcine kidney (Cathala, G., Brunel, C., Chapplet-Tordo, D., and Lazdunski, M. (1975) J. Biol. Chem. 250, 6040-6045) alkaline phosphatase, than to previously reported values for chicken (Cyboron, G. W., and Wuthier, R. E. (1981) J. Biol. Chem. 256, 7262-7268) and fetal calf (Fortuna, R., Anderson, H. C., Carty, R. P., and Sajdera, S. W. (1980) Calcif. Tissue Int. 30, 217-225) cartilage matrix vesicle alkaline phosphatase. The purified alkaline phosphatase was activated by micromolar Mg2+. The amino acid composition of cartilage alkaline phosphatase was found to be similar to that previously described for porcine kidney (Wachsmuth, E. D., and Hiwada, K. (1974) Biochem. J. 141, 273-282). Double immunoprecipitation data indicated that monoclonal antibody against cartilage alkaline phosphatase cross-reacted with fetal bovine liver or kidney enzyme but failed to react with calf intestinal or rat cartilage enzyme. Thus these observations suggest that alkaline phosphatase of matrix vesicles from calcifying epiphyseal cartilage is a liver-kidney-bone isozyme.

Alkaline Phosphatase↗
PubMed1985

Human pancreatic and biliary responses to physiological concentrations of cholecystokinin octapeptide.

To determine the functional significance of physiological plasma concentrations of cholecystokinin, five volunteers each received graded doses of intravenous infusions of cholecystokinin octapeptide (CCK-8). At each dose plasma concentrations of CCK-8 were determined and pancreatic and biliary outputs were measured. Threshold plasma concentrations of CCK-8 for augmenting pancreatic trypsin secretion were undetectable (less than 3 pmol/l), and maximal trypsin output of 21.9 +/- 1.95 k-i.u./30 min was produced by 17.1 +/- 6.4 pmol of CCK-8/1. Calculated halfmaximal output was produced by 4.7 pmol of CCK-8/1. Maximal trypsin output during infusions of CCK-8 was significantly less than that after a combination of the CCK-like peptide, caerulein, and secretin (32.95 +/- 2.16 k-i.u./30 min, P less than 0.001). Biliary bile acid and bilirubin outputs were significantly augmented only when plasma concentrations of CCK-8 were greater than 5 pmol/l. Plasma concentrations of CCK-8 in the low picomolar range exert significant effects on pancreatic and biliary secretion. CCK-8 fulfills the criteria for a circulating hormone.

Adult↗
PubMed1984

Acute effect of labetalol on blood pressure in relation to the sympathetic nervous system and plasma renin activity.

A single oral dose of 300 mg labetalol was given to 10 subjects with uncomplicated primary hypertension; its effects on blood pressure, heart rate (HR), plasma renin activity (PRA), and plasma concentration of catecholamines and of their major metabolites, octopamine ( OTP ), and dopamine-beta hydroxylase (DbH) were investigated. Although HR did not change after dosing, both systolic and diastolic blood pressure decreased in 2 hr and remained below control up to 12 hr. There was symptomatic orthostatic hypotension in two subjects in the first 2 hr after dosing. PRA decreased in the first 2 hr and followed a gradual rise that became significant at 24 hr. Although DbH did not change, plasma concentrations of norepinephrine (NE) and its major metabolites and of OTP increased between 2 and 4 hr after dosing and remained elevated up to 12 hr. There was no correlation between change in blood pressure and control levels or changes of PRA or NE concentrations.

Blood Pressure↗
PubMed1984

Oral potassium chloride and amiloride in hydrochlorothiazide-induced potassium loss.

To compare the effect of amiloride with that of oral potassium chloride (KCl) in hypokalemia, metabolic balance studies were carried out in hospitalized subjects with mild hypertension without edema who developed negative potassium balance after 4 days on hydrochlorothiazide (HCTZ). Subjects' diets contained measured amounts of sodium and potassium. While HCTZ treatment continued, oral preparations of either KCl solution or amiloride was added for 5 additional days. Potassium balance in the KCl-treated group further decreased by -44.9 +/- 32.3 mEq K+, while subjects on amiloride went into positive balance that averaged +51.7 +/- 24.1 mEq K+. Hypokalemia after HCTZ did not respond to KCl, while K+ levels rose from 3.32 +/- 0.22 to 3.67 +/- 0.26 mEq/l after amiloride.

Administration, Oral↗
PubMed1983

Plasma clonidine levels in hypertension.

Ten patients with essential hypertension were treated orally with clonidine, and the dose was titrated until the diastolic pressure fell below 90 mm Hg or at least 10 mm Hg below baseline, or until a maximum dose of clonidine of 1.2 mg/day was reached. After at least 2 wk on a constant dose of clonidine, the patients were hospitalized and blood pressure and plasma clonidine concentrations were measured by a highly specific and sensitive gas chromatographic, electron-capture method (sensitivity as low as 0.1 ng clonidine/ml). There was good correlation between daily clonidine dose and plasma clonidine concentration. The average blood pressure reduction during 12 hr after clonidine correlated poorly with steady-state plasma levels of clonidine, but when the individual maximum decrease in mean blood pressure was paired with the corresponding peak plasma concentration of clonidine, the correlation was strong.

Adult↗
PubMed1980

Biosynthesis of glycoproteins by membranes of Acer pseudoplatanus. Incorporation of mannose and N-acetylglucosamine.

Membrane preparations from Acer pseudoplatanus suspension cultures were demonstrated to incorporate radioactivity from GDP-[U-14C]mannose and UDP-N-acetyl-[6-(3)H]glucosamine into high-molecular-weight polymers characterized as glycoprotein. From 20 to 25% of the 14C was incorporated as fucose with the remainder as mannose, whereas 90% of the 3H was incorporated as N-acetylglucosamine with the remainder as N-acetylgalactosamine. Pronase digestion yielded radioactive glycopeptides that were separated into four fractions by gel-permeation chromatography and paper electrophoresis. The isolated glycopeptides differed in molecular weight and isotopes incorporated, as well as in amino-acid and monosaccharide composition. The membrane preparation also incorporated radioactivity from the added nucleotides into chloroform/methanol (2:1, v/v)- and chloroform/methanol/water (10:10:3, by vol.)-soluble lipids, and into an insoluble pellet.

Acetylglucosamine↗
PubMed1979

Accuracy and reproducibility of the Oxi/Ferm system in identifying a select group of unusual gram-negative bacilli.

The Oxi/Ferm (O/F) identification system was compared in a double-blind study to a conventional test battery for the characterization of 96 reference and clinical strains consisting of 83 nonfermentative and 13 oxidase-producing, fermentative gram-negative bacilli. The O/F tube and supplemental tests correctly identified 84% of the nonfermentative and 77% of the oxidase-producing, fermentative bacilli. However, when the supplemental tests were excluded and the biochemical profiles generated by all nine O/F tube reactions were examined, the profile accuracy reached 95% (79 of 83) for the nonfermentative and 93% (12 of 13) for oxidase-producing, fermentative bacilli. Seven of the nine O/F substrate reactions demonstrated less than or equal to 89% agreement with conventional reactions, whereas the urea and arginine reactions provided 82 and 85% agreement, respectively. Replicate O/F tests with six selected organisms demonstrated 97% identification reproducibility and 84% overall substrate reproducibility. The mean O/F identification time was 2.6 days as compared to 3.3 days for the conventional system. Although this study suggests that the O/F system is a convenient, rapid, and accurate alternative to conventional identification methods, several modifications are recommended.

Bacteria↗
PubMed1979

Meningitis and bacteremia due to Neisseria meningitidis: clinical and laboratory findings in 69 cases from Orebro county, 1965 to 1977.

The records for 69 patients with meningococcal disease during 13 years in Orebro County were reviewed. The mean incidence during this period was 2.0/100 000 persons/year. The age group less than 1 year had the highest incidence, 15/100 000 infants/year. The mortality was 7.2% and sequelae were found in 13% of the patients. Four factors were significantly more frequent in the 7 patients with psycho-neurological sequelae: (1) Age greater than 40 years; (2) A condition prior to meningococcal disease that might have been associated with a lowered resistance; (3) Muscular hypertonia and/or marked irritability on admission; (4) Fever greater than 8 days after initiation of adequate treatment. Prodromal symptoms from the upper respiratory tract were noted in 50% of the cases. Signs and symptoms before and on admission, laboratory data and complicating events were analysed for each of 4 groups: meningitis without meningococcemia (12 patients); meningitis with meningococcemia (46): fulminant meningococcemia without meningitis (6); and benign meningococcemia (5).

Adolescent↗
PubMed1977

Laboratory procedures used in the diagnosis of systemic lupus erythematosus: a review.

The literature concerning the laboratory procedures presently available to aid in the diagnosis of systemic lupus erythematosus (SLE) was reviewed to determine which of these techniques could be most valuable in the detection and management of SLE patients. The LE cell test, once the laboratory basis for SLE diagnosis, was concluded to be insensitive, non-specific, and did not correspond to clinical activity of the patient. A second procedure, antinuclear-antibody detection, although very sensitive, was not specific for SLE; therefore, its value is limited for use as a screening technique to rule out SLE. The Farr anti-DNA precipitate immunoassay, used for the measurement of antibodies to DNA, was sensitive and specific, and also correlated well with the clinical condition of the patient. Therefore, the Farr binding assay is recommended as the laboratory procedure of choice since it is useful in monitoring disease activity and may contribute to earlier diagnosis and more precise management of SLE patients.

Antibodies, Antinuclear↗