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Biomedical subjects

L A White

Publications and source records attributed to L A White.

At least 55 records · Page 3Linked to original sources
PubMed1985

Varicose veins as a source of adult human endothelial cells.

Endothelial cells can be harvested from segments of adult human saphenous vein in a varicose condition removed from patients having single or bilateral vein ligation and stripping. The cells are harvested by scraping with a scalpel, seeded on to gelatin coated or Primaria flasks and are passaged by removal with a rubber policeman. The cells cultured in this manner are maintained in a growth medium that is not supplemented with growth factors. The cells grow with a cobblestone monolayer morphology, possess angiotensin converting enzyme activity and react with antibodies to Factor VIII antigen. The cells fluoresce brightly after reaction with monoclonal antibodies specific for human endothelial cells. Thus, stripped varicose vein segments provide a readily available source of endothelial cells.

Adult↗
PubMed1983

Differences in the adhesive properties of Neisseria meningitidis for human buccal epithelial cells and erythrocytes.

The ability of clinical and carrier isolates of Neisseria meningitidis to adhere to human buccal epithelial cells and erythrocytes was investigated. Four of the 10 fimbriated strains were able to hemagglutinate. Serial subculture of three of these strains resulted in a loss of ability to hemagglutinate and was coincident with a loss of fimbriation. Other fimbriated strains were unable to hemagglutinate but did adhere to buccal epithelial cells. Subculture of one of these strains for as many as 42 passages did not result in loss of fimbriation or ability to adhere to buccal epithelial cells. The attachment of this strain to buccal epithelial cells was inhibited by glycoconjugates. Further, pH exerted different influences on the attachment of hemagglutinating and non-hemagglutinating fimbriated strains to buccal epithelial cells and erythrocytes. The results suggest that different fimbrial mechanisms are involved in the attachment of N. meningitidis to different cell types and that hemagglutination is not an absolute test for fimbriae.

Adhesiveness↗
PubMed1982

Use of microcarriers to isolate and culture pulmonary microvascular endothelium.

Microcarriers of known diameter can be used to collect endothelial cells from microvessels of the same or slightly smaller internal diameter. The procedure is illustrated by collection of endothelial cells from rabbit pulmonary pre-capillary vessels. The lungs are perfused free of blood with physiological saline and then cold vessels. The lungs are perfused free of blood with physiological saline and then cold (4 degrees C) saline (containing EDTA, 0.02%, and microcarriers 600/ml; 40-60 micrometers diameter) is perfused via the pulmonary artery. The direction of flow is reversed periodically to collect the bead-cell harvest from the arterial side. Cold shock and EDTA cause the endothelial cells to detach from the vessels under conditions such that the cells remain attached to the microcarriers. The selective attachment to microcarriers is apparently aided by the tight fit of the beads within vessels of the same diameter. Beads do not emerge on the venous side, all being trapped at the pre-capillary level. Electron microscopic examination of lungs fixed during the perfusion shows that the beads lodge in terminal arterioles and pre-capillary vessels (approximately 40-60 micrometers in diameter, with one, sometimes incomplete, muscle layer). Endothelial cells recovered on microcarriers can be allowed to migrate on to flasks and back on to beads. The resultant cultures have an endothelial morphology and possess high levels of angiotensin coverting enzyme and carboxypeptidase N activity.

Animals↗
PubMed1982

Type-specific antigens of Neisseria meningitidis serogroup A.

By using Ouchterlony immunodiffusion techniques, we defined three unique antigenic determinants (A1, A2, and A3) among six isolates of Neisseria meningitidis serogroup A. Two of these determinants (A2 and A3) were identified as lipopolysaccharides in nature and were not found to occur on the serogroup B strains of N. meningitidis that we examined. The A1 determinant commonly occurred among the serogroup B strains and was identified as a protein determinant.

Antigens, Bacterial↗
PubMed1982

Inactivation of rabies virus in reagents used for the fluorescent rabies antibody test.

Procedures for inactivating rabies virus in reagents used for the fluorescent rabies antibody test are described. Mouse brain adsorbing suspensions containing greater than or equal to 10(9) 50% lethal doses of virus per ml were rendered noninfectious by treatment with 0.1% beta-propiolactone or by heating at 56 degrees for greater than or equal to 30 min. Viable virus in tissue impression smears was inactivated by acetone fixation at 50 degrees C for greater than or equal to 30 min or by immersion in 0.1% beta-propiolactone at 37 degrees C for 2 h. Inactivated reagents gave specific and sensitive reactions in the fluorescent rabies antibody test.

Acetone↗
PubMed1981

Enzyme-linked immunosorbent assay compared with immunoprecipitation for serotyping Neisseria meningitidis and its use in demonstrating serotype polymorphism.

Rabbit antisera generated against 11 prototype strains of group B Neisseria meningitidis were tritiated by using the enzyme-linked immunosorbent assay and the Ouchterlony immunoprecipitation technique. The relative insensitivity of the immunoprecipitation technique in detecting antibody compared with the enzyme-linked immunosorbent assay was demonstrated. Cross-reactions within the group and among the 11 serotypes were characterized with respect to established serological techniques. Serotype polymorphism among the strains of N. meningitidis was demonstrated with the enzyme-linked immunosorbent assay.

Agglutination Tests↗
PubMed1979

Transport of Neisseria meningitidis cultures: growth-supporting media and freezing as an alternative.

The abilities of Transgrow (TG), Thayer-Martin (TM), and New York City (NYC) solid media to maintain the viability of 12 strains of Neisseria meningitidis under various controlled conditions were assessed. The effects of charcoal impregnation of swabs, temperature, and an enriched CO2 atmosphere were examined with holding for up to 21 days. Recovery from samples held at 35 degrees C was, in almost all instances, greater than at 22 or 4 degrees C. A strong requirement for added CO2 was demonstrated, especially at lower temperatures. No positive effect could be attributed to the use of charcoal-impregnated swabs. NYC and TM media were the best overall, with the former permitting recovery from more than 75% of all samples held on slants for 20 days at 4 degrees C in an atmosphere of 5% CO2 in air. Freezing, with holding on dry ice, was a useful alternative to the use of growth-supporting media. This latter method eliminated the requirement for an enriched CO2 atmosphere.

Culture Media↗
PubMed1979

Phase II study of 5-fluorouracil, methyl-CCNU, and daunorubicin in colorectal cancer: a Cancer and Leukemia Group B study.

The three-drug combination of 5-fluorouracil, methyl-CCNU, and daunorubicin was evaluated in 38 patients with unresectable or metastatic carcinoma of the colon. There were five partial responses and one complete response for an overall response rate of 16%. Although toxicity was tolerable, daunorubicin failed to add to the 5-fluorouracil and methyl-CCNU combination.

Adenocarcinoma↗
PubMed1978

Platelet satellitism and phagocytosis by neutrophils: association with antiplatelet antibodies and lymphoma.

Satellitism and phagocytosis of platelets by neutrophils in EDTA anticoagulated blood have been considered in vitro phenomena without clinical significance. We observed these in a patient with acute, severe thrombocytopenic purpura who subsequently proved to have malignant lymphoma. Wide oscillations in the platelet count were noted and recurrent, severe gastrointestinal bleeding occurred even when the platelet count was normal. Platelet function was abnormal as shown by decreased platelet adhesion to glass beads, absence of a secondary wave of aggregation in response to ADP and eqinephrine, and no aggregation with collagen. Suspension of control platelets in the patient's plasma induced similar aggregation defects in the control platelets. Combination chemotherapy resulted in regression of lymphadenopathy, but platelet abnormalities and bleeding persisted. Platelet satellitism and phagocytosis by neutrophils seen on peripheral blood films may be associated with true thrombocytopenia, abnormal platelet function and bleeding with an underlying systemic disease.

Antibodies↗
PubMed1976

Effect of gentamicin on growth of viral, chlamydial, and rickettsial agents in mice and embryonated eggs.

Gentamicin, at concentrations up to 500 mug/ml, showed no effect on the replication, yield, or infectivity of seven viruses or on the agents of psittacosis and meningopneumonitis when grown in mice or embryonated eggs. At the 500 mug/ml level, lymphogranuloma venereum cultures had a slight reduction in infectivity. Rickettsia akari demonstrated susceptibility at the 5 mug/ml level, whereas R. rickettsii, R. mooseri, and R. canada grown in embryonated eggs were susceptible in varying degrees to gentamicin at or above the 50 mug/ml concentration.

Animals↗
PubMed1976

Preparation of rabies fluorescein isothiocyanate-labeled immune globulin from mouse hyperimmune ascitic fluids.

Immunization conditions for the production of mouse immune ascitic fluids to be used for the preparation of rabies fluorescent antibody (FA) conjugate are presented. The use of optimal concentrations of ammonium sulfate for precipitation of gamma globulin resulted in a fraction consisting of 75% gamma globulin and 25% alpha-beta globulins with no detectable albumin. Dialysis labeling of the globulin fration with fluorescein isothiocyanate produced a specific rabies FA conjugate with negligible nonspecific background staining. This procedure represents a simple means of producing rabies FA conjugate.

Animals↗
PubMed1975

Improved large-volume sampler for the collection of bacterial cells from aerosol.

A modified large-volume sampler was demonstrated to be an efficient device for the collection of mono-disperse aerosols of rhodamine B and poly-disperse aerosols of bacterial cells. Absolute efficiency for collection of rhodamine B varied from 100% with 5-mum particles to about 70% with 0.5-mum particles. The sampler concentrated the particles from 950 liters of air into a flow of between 1 and 2 ml of collecting fluid per min. Spores of Bacillus subtilis var. niger were collected at an efficiency of about 82% compared to the collection in the standard AGI-30 sampler. In the most desirable collecting fluids tested, aerosolized cells of Serratia marcescens, Escherichia coli, and Aerobacter aerogenes were collected at comparative efficiencies of approximately 90, 80, and 90%, respectively. The modified sampler has practical application in the study of aerosol transmission of respiratory pathogens.

Aerosols↗
PubMed1975

Production of influenza virus complement-fixing antibody in mouse ascitic fluid.

Suspension cultures of BHK-21/13s cells infected with either A/Hong Kong/8/68 or B/Massachusetts/3/66 strains of influenza were used to prepare type-specific influenza ribonucleoprotein-immunizing antigens. These antigens were used in comparing four immunization schedules in the production of immune mouse ascitic fluids. Large volumes of ascitic fluids were obtained by these schedules. These fluids contained type-specific complement-fixing antibody and were devoid of nonspecific host tissue or heterologous cross-reactions.

Animals↗
PubMed1975

Opposing regulatory influences of cyclic guanosine monophosphate and cyclic adenosine monophosphate in the control of cardiac muscle contraction.

The effects of acetylcholine chloride (ACh) and isoproterenol (Iso) on myocardial levels of guanosine 3', 5'-monophosphate (cyclic GMP) and adenosine 3', 5'-monophosphate (cyclic AMP) and on force of contraction were studied in elelctrically driven isolated rabbit atria. Incubation of atria with Tyrode's solution containing ACh (5 x 10(-7) M) produced significant decreases in contractile force that were associated with significant elevations in atrial cyclic GMP levels. Atrial levels of cyclic AMP were significantly lowered at 15 sec after the addition of ACh but were only slightly lowered at earlier time intervals. The effects of acetylcholine on force of contraction and on cyclic nucleotide levels were prevented with atropine (1 x 10(-7) M). The addition of Iso (1 x 10(-7)-M) to isolated atria produced significant increases in contractile force that were associated with significant elevations in effects of Iso on force of contraction and on cyclic nucleotide levels were prevented with practolol (1 x 10(-5) M). The increases in atrial cyclic GMP and cyclic AMP levels following addition of ACh and Iso, respectively, precede the changes in contractile force. These data support our hypothesis that cyclic AMP and cyclic GMP exert oppositional effects on cardiac contrctility.

Acetylcholine↗