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Biomedical subjects

A Barr

Publications and source records attributed to A Barr.

At least 19 recordsLinked to original sources
PubMed1992

Phosphorylation of the C-terminal domain of the Na+/H+ exchanger by Ca2+/calmodulin-dependent protein kinase II.

The Na+/H+ exchanger is a pH-regulatory protein that extrudes one H+ ion in exchange for one Na+ ion when intracellular pH declines. A number of studies have shown phorbol ester stimulation of activity in intact cells, leading to the idea that the exchanger is regulated by protein kinase C-mediated phosphorylation in vivo. cDNA encoding the protein has been cloned, and a recent model suggests a large internal cytoplasmic C-terminal domain that may be a site of regulation of the exchanger [Sardet, Franchi & Pouyssegur (1989) Cell 56, 271-280]. We examined this region of the protein using a rabbit cardiac Na+/H+ exchanger cDNA clone. cDNA of the Na+/H+ exchanger, coding for the C-terminal 178 amino acid residues, was cloned into the expression vector pEX-1 and expressed as a fusion protein with beta-galactosidase. The fusion protein reacted with an antibody produced against a synthetic peptide of the C-terminal 13 amino acid residues of the Na+/H+ exchanger, confirming the identity of the expressed protein. Control and experimental pEX-1-Na+/H+ exchanger protein was purified on a p-aminophenyl beta-D-thiogalactopyranoside-agarose column. Purified Ca2+/calmodulin-dependent protein kinase II readily phosphorylated the Na+/H+ exchanger protein in a Ca(2+)- and calmodulin-dependent manner in vitro, but this region of the protein was not a substrate for purified protein kinase C or for the catalytic subunit of cyclic AMP-dependent protein kinase. Control-expressed beta-galactosidase was phosphorylated to a maximal level of 0.77 +/- 0.17 mol of Pi/mol (mean +/- S.E.M., n = 6) whereas the fusion protein was phosphorylated to a maximal level of 4.09 +/- 0.39 mol of Pi/mol (n = 6), suggesting one site of phosphorylation in beta-galactosidase and three in the C-terminal domain of the Na+/H+ exchanger. Examination of the deduced amino acid sequence of this part of the exchanger reveals three consensus sequences for Ca2+/calmodulin-dependent protein kinase II. These results suggest that the exchanger may be directly regulated in vivo by calmodulin-dependent protein kinase II but not by protein kinase C or cyclic AMP-dependent protein kinase.

Amino Acid Sequence↗
PubMed1991

Identification of the protein and cDNA of the cardiac Na+/H+ exchanger.

We examined the myocardial form of the Na+/H+ exchanger. A partial length cDNA clone was isolated from a rabbit cardiac library and it encoded for a Na+/H+ exchange protein. In comparison with the human Na+/H+ exchanger, the sequence of the 5' end of the cDNA was highly conserved, much more than the 3' region, while the deduced amino acid sequence was also highly conserved. To further characterize the myocardial Na+/H+ exchange protein, we examined Western blots of isolated sarcolemma with antibody produced against a fusion protein of the Na+/H+ exchanger. The antibodies reacted with a sarcolemma protein of 50 kDa and with a protein of 70 kDa. The results show that the rabbit myocardium does possess a Na+/H+ exchanger protein homologous to the known human Na+/H+ exchanger.

Amino Acid Sequence↗
PubMed1979

Spinal mobility in the adolescent.

The ranges of spinal movement in 390 healthy children aged from 10 to 15 years have been recorded. These measurements are in two planes, anterior and lateral; they are quick and easy to perform and require no special equipment, just a tape measure. Many conditions occurring in childhood can lead to limitation of spinal movement: these include juvenile ankylosing spondylitis, spondylolisthesis, Scheuermann's vertebral osteochondritis, discitis and vertebral fractures, the latter being not uncommon in children receiving prolonged corticosteroid therapy. The purpose of the present paper is to define the normal range for anterior and lateral spinal flexion in adolescents and to correlate these with sex, age, height and weight.

Adolescent↗
PubMed1979

Changes in refraction between the ages of 1 and 3 1/2 years.

A study has been made of the changes in refraction as a sample of 148 children grew between the ages of 1 and 3 1/2 years. There was no decrease in hypermetropia, but there was a significant decrease in the incidence of astigmatism. Study of the changes in the refraction in the horizontal and vertical meridia of individual eyes gave clear evidence of a trend towards emmetropia if the initial refraction in either meridian was myopic or less than +2.50 D. Above that level the refraction became more or less hypermetropic.

Astigmatism↗
PubMed1979

Refraction of 1-year-old children after cycloplegia with 1% cyclopentolate: comparison with findings after atropinisation.

Cyclopentolate 1% is significantly less effective than atropine 1% at producing cycloplegia in 1-year-old children. If cycloplegic refraction is to be used for investigation or screening children for visual defects during the sensitive period, the more prolonged and profound cycloplegia following atropine could potentially have a disastrous effect on the development of vision. Cyclopentolate 1% would have to be used, and allowance made for its inadequacy as a cycloplegic.

Atropine↗
PubMed1979

Hepatitis Be antigen and antibody in hepatitis B surface antigen positive blood donors.

In a study of 105 asymptomatic HBsAg positive blood donors, 9 (8.6%) were found to have HBeAg, 38 (36.2%) anti-HBe, and the remaining 58 (55.2%) neither marker detectable by gel diffusion. There was no correlation between HBeAg/anti-HBe status and HBsAg sub-types, Glm allotypes, the presence of anti-Gm, red cell antibodies, or rheumatoid factor. Rheumatoid factor activity could be removed from anti-HBe positive sera without removing anti-HBe activity, indicating that separate entities were involved. HBeAg was found only in donors under the age of 30 (P less than 0.005), while anti-HBe did not show an age-related trend. HBeAg was also found less commonly in donors of blood group A than in the total carrier population (P less than 0.05), indicating an apparent protection in carriers of group A. The blood group distribution for the 105 HBsAg positive donors was similar to that of the general population.

ABO Blood-Group System↗
PubMed1979

Fulminant disseminated intravascular coagulation in advanced gastric carcinoma.

A case of fulminant disseminated intravascular coagulation (DIC) in a 51-year old man, presenting with bleeding gastric adenocarcinoma, is reported. In spite of initial hematologic improvement by replacement therapy the patient died on the fifth day after admission. The rare association of DIC with adenocarcinoma of the stomach is discussed.

Adenocarcinoma↗
PubMed1978

Quantitation of the anti-inflammatory agent fenbufen and its metabolites in human serum and urine using high-pressure liquid chromatography.

Specific procedures are described for the determination of fenbufen and its metabolites in serum and urine using high-pressure liquid chromatography. Serum or urine extracts were chromatographed on a bounded reversed-phase partitioning column. The sensitivity of the assay for fenbufen was 0.5 microgram/ml in serum with 2-ml samples and 1.0 microgram/ml in urine with 1-ml samples. The procedures are suitable for bioavailability and pharmacokinetic studies.

Adult↗
PubMed1977

Demand for patient care.

A study was performed to determine the extent to which patients of all types were receiving inappropriate levels of care. The needs of patients in acute and supporting hospitals, people in residential homes, and patients cared for at home were assessed. A sixth of the hospital inpatients did not need hospital care, while 5% of those in residential homes and 5% of those at home did need hospital services. These findings indicate that a realistic provision of hospital beds would be 4 per 1000 population for all specialties except regional specialties, psychiatry, mental subnormality, obstetrics, and paediatrics. About a third of these beds need to be acute, while the rest may be in supporting or community hospitals. Thus the current provision of acute beds (2-0 to 2-5 per 1000 population) exceeds actual need.

Female↗
PubMed1975

Which techniques should be used to screen blood donations for hepatitis B surface antigen?

Preservation of all donor sera already tested for Hepatitis B surface antigen (HBsAg) by counterimmunoelectrophoresis (C.I.E.P.) allowed C.I.E.P., reversed passive haemagglutination (R.P.H.A.), and radioimmunoassay (R.I.A.) to be evaluated as screening techniques. Out of 165 811 donors tested for the first time 207 were found by C.I.E.P. to be positive for HBsAf-a prevalence of 0-12%. At the next donation 10 of those apparently negative on first screening were HBsAg positive by C.I.E.P., and nine of these were shown by retesting with R.P.H.A. and R.I.A. to have been positive at the earlier donation. These nine false negatives caused four cases of transfusion-transmitted HBsAg-positive hepatitis. On comparative screening of 22 239 donations C.I.E.P. detected 27 sera positive for HBsAg, R.P.H.A. 39, and R.I.A. 41. Thus R.I.A. increased the detection rate by more than half over C.I.E.P. From these 14 further false-negative donations by C.I.E.P. six cases-one fatal-of HBsAg-positive hepatitis occurred. The number of false positive reactions when using R.P.H.A. or R.I.A. for screening was less than 1%. As many as 700 donations in one day have been tested by R.P.H.A. or R.I.A. R.P.H.A. is faster and less expensive than R.I.A., but R.I.A. is more objective. Either R.P.H.A. or R.I.A. should replace C.I.E.P. as the routine method of screening donor sera for HBsAg.

Blood Donors↗
PubMed1975

Detection and quantitation of tetanus antitoxin in blood donations.

Passive haemagglutination and IEOP have been used both to detect and to measure tetanus antitoxin in human donor sera. Forty percent of blood donors had detectable antitoxin but only 9% had levels suitable for production of human antitetanus immuoglobulin (larger than or equal to 2 IU/ml). The incidence of high titre antitoxin was significantly greater in men and was unrelated to the ABO blood group system. The prevalence of antitoxin in selected donor groups and immunized staff is shown.

ABO Blood-Group System↗