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Biomedical subjects

J O'Brien

Publications and source records attributed to J O'Brien.

At least 253 records · Page 14Linked to original sources
PubMed1980

Conditions for measuring DNA synthesis in PHA stimulated human lymphocytes in 20 microliters hanging drops with various cell concentrations and periods of culture.

We have studied conditions for measuring the uptake of [3H]thymidine ([3H]Tdr) by human lymphocytes in inverted microcultures, varying cell concentrations and periods in culture. Analysis of variance of the log values for [3H]Tdr uptake may be used to separate effects of variables and their interactions. A pulse time of 2 h, a total thymidine concentration of about 1 microgram/ml and a specific activity of [3H]Tdr of 2 Ci/mmole were optimal. Variables such as cell concentration, period of culture, type of serum and dose of PHA were shown to interact, suggesting that these variables should be examined together especially when comparing different samples of lymphocytes. Conditions for doing this simply in small volumes are now available for culturing, thymidine pulsing, harvesting and analysis of data.

Cell Division↗
PubMed1980

Metastable creatine kinase MM and complexes of creatine kinase BB and immunoglobulin G, "atypical" isoenzymes with similar electrophoretic mobility.

Metastable creatine kinase MM isoenzyme was isolated and partially purified from homogenates of myocardium and skeletal muscle by gradient elution on carboxymethyl cellulose. This variant isoenzyme migrated between the MM and MB isoenzymes on agarose electrophoresis, accounted for 3.5% of the total creatine kinase activity in each tissue, was not a macromolecule, and had stable electrophoretic mobility only in borate buffer (0.02 mol/L). By comparison, the creatine kinase isoenzymes with similar "atypical" electrophoretic mobility in serum specimens were complexes of the BB isoenzyme and immunoglobulin G. These complexes were measured by a radioimmunoassay specific for the creatine kinase B-subunit and eluted predominantly with the MB isoenzyme in a commercial anion-exchange reagent system.

Creatine Kinase↗
PubMed1979

A simple technique for harvesting lymphocytes cultured in Terasaki plates.

A simple method has been developed for harvesting lymphocytes from Terasaki microplates based on a culture technique where the plates are inverted and the cells grown on the hanging meniscus of the medium in each well. Sixty individual filter discs were prepared in wells in a polycarbonate harvesting plate. A dry Terasaki plate was used to cut these filters with the harvester acting as a die. The inverted culture plate was then lowered onto the harvester to allow the cells on the meniscus from each well to be absorbed on the appropriate filter disc. The culture plate was then discarded and the cells on the filters washed in the harvester. The wash solutions were removed by suction through holes below each filter. The time taken to harvest the cultures from 60 wells of a plate was 3--5 min.

Cell Separation↗
PubMed1978

Effect of levamisole on metabolism of phagocytic cells.

The effect of levamisole (LMS) on glucose metabolism was studied using a protozoan phagocytic model and human leukocytes. At concentrations of greater than 10 microgram/ml, LMS inhibited glucose metabolism in the protozoan phagocytic model. Glucose metabolism in both the phagocytic model and normal peripheral blood leukocytes was, however, minimally altered when exposed to levels of LMS of less than 10 microgram/ml. In contrast, myeloblasts from a child with leukemia seemed to have increased metabolic activity and 5 microgram/ml of LMS markedly reduced the glucose metabolism. These preliminary studies suggest that LMS can alter glucose metabolism of certain cells and that some malignant cells may be directly inhibited metabolically by LMS.

Child↗
PubMed1977

Reactions and serologic responses after administration of inactivated monovalent influenza A/swine virus vaccines. I. Immunization of children and adults with influenza A/Shope virus vaccines.

Reactivity and immunogenicity of three inactivated, zonally purified, monovalent influenza A/swine virus vaccines were studied in children and adults. Each dose of vaccine contained either 400 chick cell-agglutinating (CCA) units/0.5 ml or 200 CCA units/0.25 ml. The vaccines contained either whole virus or ether-extracted, subunit virus with or without 1.5 mg of A1PO4/0.5 ml. Children younger than 10 years of age received a half dose. Substantial system reactions, including temperature increases of 2.2 F-4.9 F, were observed in all children who received whole-virus vaccines. In contrast, ether-extracted, subunit vaccines (with or without A1PO4) were minimally pyrogenic in 185 subjects. Two doses of subunit vaccine in subjects younger than 25 years of age were immunologically equivalent to a single dose in older subjects. We concluded that two doses of ether-extracted, subunit virus vaccine with Hsw1N1 antigen, administered at least four weeks apart, are serologically effective for immunization of seronegative subjects of any age and that this dosage regimen should be used in young children in whom whole-virus vaccines are unacceptably reactive.

Adolescent↗
PubMed1977

Reactions and serologic responses after administration of inactivated monovalent influenza A/swine virus vaccines. II. Immunization of children with influenza A/New Jersey/X-53 virus vaccines.

Reactivity and immunogenicity of two inactivated, zonally purified, ether-extracted, influenza A/New Jersey/X-53 subunit virus vaccines were studied in 103 children three to 18 years of age. Children aged nine years of younger received doses of 100 or 200 chick cell-agglutinating (CCA) units, and those older than nine years received doses of 200 or 400 CCA units. Vaccines were given intramuscularly. Two doses were given at intervals of four weeks. The vaccines were minimally pyrogenic, causing only two instances of temperatures of greater than 100.0 F. Other systemic reactions were observed infrequently. Tenderness at the site of injection occurred relatively frequently but was of no medical consequence. The geometric mean titers of homologous antibody, which ranged from 1:52 to 1:75 after administration of two doses, were statistically equivalent in all treatment groups. Titers of antibody of greater than or equal to 1:40 to the influenza A/New Jersey/8/76 virus strain were achieved by 88% of the vaccinees. We concluded that two doses of ether-extracted, subunit influenza A/New Jersey/X-53 virus vaccine were well tolerated and, when given at least four weeks apart, were serologically effective for immunization of children aged three to 18 years.

Adolescent↗
PubMed1977

Lecithin/spingomyelin ratio procedure by thin-layer chromatography.

We assessed several modifications of thin-layer chromatography for evaluation of amniotic fluid lecithin/sphingomyelin ratios. For a procedure which is reliable, economical, and easy to perform, we preferred laboratory-prepared plates using SI-LICAR TLC-7GF. For spot detection, we preferred the iodine vapor method.

Amniotic Fluid↗
PubMed1976

HL-A groups in pernicious anaemia.

There is a significant association with HL-A3 type and pernicious anaemia. In addition there is a negative association with HL-A2. There is no association between HL-A type and the presence or absence of immunity to intrinsic factor.

Anemia, Pernicious↗