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Biomedical subjects

J J Alexander

Publications and source records attributed to J J Alexander.

At least 91 records · Page 5Linked to original sources
PubMed1982

Blood cultures in bacteremia.

Blood cultures in a 700-bed hospital were examined for clinical relevance. During a six-month period 5,154 blood samples were drawn from 1,091 patients. Of the 124 patients with positive blood cultures, 7% had polymicrobic isolates. A review of hospital records for a three-year period revealed 162 charts with adequate documentation for evaluation of bacteremia. An additional 11 charts were found with inappropriately negative blood cultures. Fifteen percent of these patients were found to have polymicrobic isolates. The importance of establishing guidelines and criteria concerning acceptable blood culture practices is detailed.

Bacteria↗
PubMed1980

A human liposarcoma cell line.

The properties of a new cell line derived from a human retroperitoneal liposarcoma are described. The cells do not grow at low cell concentrations and contain in their cytoplasm large numbers of droplets that stain with Oil Red O. No indication of the presence of endogenous virus particles could be found. The mean chromosome number per cell is 36, with several constant markers, the most conspicuous of which is a large submetacentric marker due to a translocation between chromosomes 4 and 11, which is present in every cell. The liposarcoma cells show an enhanced uptake of [14C]acetate compared to normal human fibroblasts.

Acetates↗
PubMed1980

Overnight refrigeration of urine specimens for culture.

Some authorities state that urine may be refrigerated overnight and still be satisfactory for quantitative bacteriologic evaluation. The papers cited appear to us to be inadequate. Four hundred and fourteen urine cultures were evaluated comparing colony count before and after overnight refrigeration. Overnight refrigeration appears to be a satisfactory means of urine preservation for culture.

Humans↗
PubMed1980

PLC/PRF/5 (Alexander) hepatoma cell line: further characterization and studies of infectivity.

The Alexander hepatoma cell line, PLC/PRF/5, was studied for evidence of hepatitis B virus markers and alpha-fetoprotein. Only hepatitis B surface antigen and alpha-fetoprotein were detected. Induction experiments with 5-iodo-2'-deoxyuridine and inoculation of chimpanzees with whole cells or tissue culture fluid did not reveal evidence of synthesis of additional hepatitis B virus markers or of production of infectious virus.

Animals↗
PubMed1980

State of hepatitis B viral DNA in a human hepatoma cell line.

PLC/PRF/5, a tissue culture cell line isolated from a human hepatocellular carcinoma and producing hepatitis B surface antigen, was studied for the presence of hepatitis B virus (HBV)-specific DNA and RNA. PLC/PRF/5 cell DNA accelerated the rate of reassociation of HBV [32P]DNA, and quantitative experiments indicated that the cells contained approximately four copies of viral DNA per haploid, mammalian cell DNA equivalent. PLC/PRF/5 DNA accelerated the rate of reassociation of all individual restriction endonucleases HincII and HaeIII fragments of HBV [32P]DNA, indicating that DNA from all regions of the viral genome is present in the cells. This suggests that these cells contain at least most, and possibly all, of the viral genome. Digestion of PLC/PRF/5 cell DNA with restriction endonuclease HindIII (an enzyme found not to cleave the DNA of any HBV isolate so far examined) yielded only three fragments, all larger than virion DNA, which contained HBV DNA base sequences, suggesting that HBV DNA is integrated in high-molecular-weight DNA at three different sites in these cells and that there is no viral DNA in an episomal form. PLC/PRF/5 cell [32P]RNA was found to hybridize with all restriction fragments of HBV DNA adequately tested, indicating that at least most, and possibly all, of the viral DNA in these cells is transcribed.

Base Sequence↗
PubMed1979

Cell lines with spontaneous secretion of pregnancy-associated alpha 2-globulin.

Pregnancy-associated alpha 2-globulin (PA alpha 2G) was quantitated by radioimmunoassay in culture media from 34 exponentially growing human cell lines. Only 8/34 cell lines produced PA alpha 2G. The highest secretion was found in cell lines of histiocytic lymphoma origin while it was low in some carcinoma-derived lines. The results may support an assumption that PA alpha 2G is a normal cell product of B-lymphoid, monocytic and epithelial cells but may also simply indicate that ectopic PA alpha 2G production is especially common in tumors derived from such cells. The availability of PA alpha 2G-producing cell lines should facilitate studies of the immunoregulatory role of this protein.

Alpha-Globulins↗
PubMed1979

Labeling of hepatitis B virus surface antigen (HBsAg) synthesized in a HBsAg-producing hepatoma cell line.

Hepatitis B virus surface antigen (HBsAg) could be studied until recently only by isolating it from the blood of carriers, thus making incorporation of radioactive precursors into this protein(s) impossible. The isolation of a cell line producing HBsAg [Alexander et al, 1978] has eliminated this obstacle. The cell line was therefore used for labeling HBsAg either with 35S-methionine or with 35S-cystine. HBsAg was purified by pelleting the component and by isopycnic centrifugation in CsCl gradients. HBsAg-positive fractions (as determined by solid-phase radioimmunoassay) were isolated from the gradients and analyzed in sodium dodecyl sulfate-containing polyacrylamide gels. It was found that although HBsAg contains substantial amounts of 35S-cystine, very little 35S-methionine was incorporated into this protein. In contrast, both labels were found in other structures having a buoyant density of about 1.3 gm/cm3 in CsCl. It was concluded that HBsAg is very low in methionine, and therefore this amino acid should not be used for labeling HBsAg in cells or in a cell-free system. Analysis of 35S-cystine-labeled HBsAg-positive material (buoyant density about 1.2 gm/cm3 in CsCl) revealed five proteins with molecular weights in the range of 48,000-82,000.

Carcinoma, Hepatocellular↗
PubMed1979

Propagation of human hepatitis A virus in a hepatoma cell line.

Hepatitis A virus (HAV) was isolated directly from human feces and propagated serially in an HBsAg producing human hepatoma cell line. No cytopathic effect was observed in the tissue culture and no detectable amounts of HAV were present in the tissue culture supernatant fluid. However, increasing amounts of hepatitis A antigen (HAAg) were detected by radioimmunoassay in the cell extracts obtained by freezing and thawing of cells. Specificity of the HAAg determination was shown by neutralization with convalescent sera of marmosets experimentally infected with the MS-1 strain of hepatitis A and by the absence of this neutralization with preinoculation sera. HAAg was first detected after four weeks in the cell extract of infected cultures after inoculation of 10(2)--10(4) tissue culture infectious doses of HAV from second passage.

Antigens, Viral↗
PubMed1979

Polypeptides of hepatitis B virus surface antigen produced by a hepatoma cell line.

The PLC/PRF/5 cell line derived from a human hepatoma produces hepatitis B surface antigen (HBsAg) in 22-nm particles of the same buoyant density as those found in the serum of infected patients. The HBsAg particles from this cell line were labeled with [35S]methionine and purified, and the polypeptides were compared by sodium dodecyl sulfate-polyacrylamide gel electrophoresis with those of serum-derived particles. The two major polypeptides of serum-derived HBsAg particles (p20 and p23) were found in the same relative amounts in the particles from the cell line. The three smallest of the five minor components observed in HBsAg particles from serum were present in particles from the cell line. These polypeptides (p31, p36, and p43), as well as p20 and p23, were precipitated with anti-HBs-containing serum. The two largest polypeptides of serum particles (p49 and p66) were not detected in particles from these cells. When the PLC/PRF/5 HBsAg particles were radiolabeled with tritiated sugars, p23, and not p20, was found to contain radioactivity, indicating that the pattern of polypeptide glycosylation is similar to that of serum HBsAg. None of the other possible gene products of hepatitis B virus was detected in the PLC/PRF/5-derived HBsAg particles, in the cells, or in the cell supernatants.

Carcinoma, Hepatocellular↗
PubMed1978

Antibody to hepatitis B surface antigen is not cytotoxic to antigen-secreting hepatocytes.

A continuously growing cell line which produces hepatitis B surface antigen was grown in the presence of antibody to the surface antigen. Antibody from animal and human sources was used. Neither growth rate nor cell morphology was affected and the cells did not inactivate the antibody over a 4-day incubation period. The surface antigen produced was specifically neutralized. These results suggest that hepatic injury occurring in response to hepatitis B virus infection is not mediated by humoral immunity to the surface antigen.

Antibodies, Viral↗
PubMed1978

In vitro effects of bleomycin on a carcinoma of the oesophagus cell line.

A dose of 10 microgram/ml bleomycin inhibited the growth of oesophageal carcinoma cells and non-squamous cells in vitro. Drug concentration, density of cells and the time of exposure to the drug were important variables. The oesophagus cancer cells increased in volume by 2,5 +/- 0,2% per hour until the onset of lysis at 96 hours. The effects of the drug were irreversible even when the exposure time was only 24 hours. A certain proportion of the cell population was resistant to bleomycin and these cells remained resistant when the drug was removed for 48 hours and then replaced. No drug inactivation or uptake could be detected with the use of microbiological assay after 4 days of incubation with 3 cell types. There is poor correlation between in vitro and in vivo results.

Bleomycin↗
PubMed1976

Establishment of a continuously growing cell line from primary carcinoma of the liver.

A continuously growing cell line has been established from autopsy material taken from a primary liver carcinoma, a cancer which has a high incidence in Southern Africa. The cell line was initiated from multifocal areas of outgrowth in the primary culture, and adaptation to in vitro conditions was completed after 18 months. The cells resemble hepatocytes in culture, have a doubling time of 35-40 hours and a plating efficiency of 40-50%. No virus particles have been found in the cells by ultrastructural examination. The isozyme pattern and the karyology of the cells are human. The chromosome pattern is heteroploid (mean number 56) and there are marker chromosomes.

Adult↗
PubMed1976

Hepatitis B surface antigen produced by a human hepatoma cell line.

The human hepatoma cell line, PLC/PRF/5, was shown to produce hepatitis B surface antigen (HBsAg). Immunologically reactive material was present in the supernatant tissue culture medium in significant amounts, and was associated with spherical particles approximately 20 nm in diameter. The rate of antigen production by the cells was estimated at 500 ng/day/10(6) cells by reference to a purified HBsAg standard. All immunological activity was neutralized by specific antibody and the subtype was ad. The studies reported here broaden the scope of investigations on both the in vitro production of HBsAg and the association between this antigen and primary liver cancer.

Carcinoma, Hepatocellular↗
PubMed1976

Chromosome analyses of two recently established human tumour cell lines derived from a carcinoma of the oesophagus and a primary liver tumour.

An oesophageal carcinoma cell line was karyotyped at passages 8,48,64 and 88. It showed a persistent loss of D group chromosomes and subtelocentric, acrocentric, dicentric and other markers were frequently present. During 80 passages the modal number declined from 60,5 to 54,09. The chromosome pattern of a hepatoma cell line was studied at passages 15/17 and 28. It showed a loss of D and G group chromosomes and the presence of various markers including a D/G fusion.

Carcinoma, Hepatocellular↗