Search PubMed⌕ Search

Biomedical subjects

B Griffiths

Publications and source records attributed to B Griffiths.

At least 73 records · Page 4Linked to original sources
PubMed1985

In vitro studies on the fibrinolytic, thrombolytic and fibrinogenolytic properties of a tissue plasminogen activator from guinea pig keratocytes.

The fibrinolytic and thrombolytic properties of a tissue plasminogen activator (tPA) purified from the conditioned medium of an established guinea pig keratocyte (GPK) cell line were investigated in in vitro systems and compared with urokinase. Using the fibrin clot lysis assay, GPK activator appears to be similar to human melanoma tPA and not to human urokinase. GPK activator also caused negligible fibrinogen breakdown, when incubated with human plasma at 37 degrees C over 23 hr. Urokinase on the other hand caused significant fibrinogenolysis, under similar conditions. Comparison of the lysis of plasma clots by GPK activator and human urokinase have shown that GPK activator was a much more effective fibrinolytic agent than urokinase, especially at lower concentrations (less than 50 IU/ml). Studies on the thrombolytic effect of GPK activator on the lysis of aged and cross-linked whole human blood clots and plasma clots hanging in artificially circulating human plasma suggest that GPK activator can lyse both these types of clots equally well. The lysis is dose dependent, attaining complete lysis within 3-6 hr with the concentration of GPK activator in the range of 1-5 micrograms/ml plasma. It is concluded that GPK activator has a higher fibrinolytic and thrombolytic activity and lower fibrinogenolytic activity than urokinase.

Animals↗
PubMed1985

Human lactase and the molecular basis of lactase persistence.

Human lactase purified from detergent extracts of the total membrane fraction of postmortem jejunum by means of monoclonal immunoadsorbent chromatography appears to be a dimer of subunits identical in Mr (160K). Trypsin or papain removes a small hydrophobic anchoring peptide from each subunit to give a hydrophilic enzyme which no longer interacts with detergent micelles. Lactase hydrolyzes, besides lactose, cellobiose and the synthetic substrates, 4-methylumbelliferyl-beta-galactoside and beta-glucoside, as well as phlorizin; but it does not hydrolyze glucocerebroside. Phlorizin hydrolase is associated with lactase under all conditions investigated; coincident staining on immunodiffusion and immunoelectrophoresis, coincident elution on immunoadsorbent chromatography and on gel filtration in a dissociating buffer, and correlated reduction in activity in lactase-nonpersistent individuals. Adult and infant lactases are indistinguishable by titration or immunodiffusion against polyclonal rabbit antibodies. Adult individuals low in lactase activity also show a corresponding reduction in cross-reacting material. These observations suggest that lactase persistence is due to the continued synthesis of the infant enzyme.

Antibodies, Monoclonal↗
PubMed1985

Production of herpes simplex virus from MRC-5 cells grown in a glass bead culture system.

The failure of microcarrier systems to provide significant quantities of infectious Herpes simplex virus (HSV) for vaccine production purposes led to an assessment of glass bead column cultures for this requirement. Glass bead columns giving approximately 12000 cm2 culture surface areas have been inoculated at various densities with MRC-5 cells, grown to confluency (as determined by steady state glucose utilization) and infected with HSV. The culture system proved at least as effective as comparable roller bottle cultures.

Cell Adhesion↗
PubMed1984

Glycoproteins in cystic fibrosis: a lectin binding study.

Ten lectins have been used to detect glycoproteins, after SDS polyacrylamide gel electrophoresis and gel isoelectric focusing, in fibroblasts, red cell membranes, urine, and plasma of patients and obligate heterozygotes with cystic fibrosis. No disease specific changes were detected but considerable individual variation was observed, some of which was attributed to known genetic polymorphisms unrelated to cystic fibrosis.

Adult↗
PubMed1983

A genetic polymorphism of a human urinary mucin.

We report here a novel genetically determined polymorphism of a human urinary mucin which is demonstrable by the separation technique of SDS polyacrylamide gel electrophoresis, followed by detection with radio-iodinated lectins. The mucins are demonstrable using various lectins but the polymorphism is most easily recognized using peanut agglutinin and we therefore propose to designate this new genetic locus PUM (peanut-reactive urinary mucin). Four common alleles have been identified and an autosomal codominant mode of inheritance has been found in the families studied so far.

Alleles↗
PubMed1983

Production of a fibrinolytic enzyme from cultures of guinea pig keratocytes grown on microcarriers.

Microcarrier technology was investigated as a means of producing a fibrinolytic enzyme, for the treatment of occlusive thrombotic vascular disorders, in sufficient quantity to carry out an evaluation of its clinical potential and the economics of large scale production. Preliminary results showed that the cells grew well and produced significant quantities of the enzyme at high (10 g/1) microcarrier concentrations.

Animals↗
PubMed1983

An examination of the data and concepts germane to the oxygenation of cultured animal cells.

With the increasing demand for high productivity cultures (including unit process monolayer cultures) oxygenation has now become a problem much sooner in the scaling-up process. There are no problems with measuring the dissolved oxygen concentration, but maintaining a desired concentration is one of the major challenges in Animal Cell Technology. It is of key importance, because the oxygen level has critical effects on cell metabolism (13, 5, 9, 22, 40, 36) which not only affect cell growth but also the products that can be expressed by the cell. As the oxygen level for these two functions is often different (e.g. the production of Ig from lymphocytes (27) more attention must be paid to defining the optimal oxygen levels and methods whereby such levels can be maintained in the least destructive manner.

Animals↗
PubMed1982

Comparison of utilization of medical services by alcoholics and non-alcoholics.

To determine whether medical costs for alcoholics are higher than those for non-alcoholics, inpatient and outpatient costs for medical services of 191 alcoholics with 191 non-alcoholic matched controls were compared over four years. Results confirm that alcoholics are higher-cost users of medical services than non-alcoholics. (Am J Public Health 1982; 72:600-602.)

Alcoholism↗
PubMed1981

Utilization of medical services by alcoholics participating in a health maintenance organization outpatient treatment program: three-year follow-up.

IN a cumulative 3-yr follow-up study of utilization of medical services by alcoholics participating in a health insurance maintenance organization (HMO) outpatient alcoholism treatment program, expenditures of 59 alcoholics were compared with those of 78 alcoholics who chose not to participate. Results show significant differences in dollar cost per patient per year between groups in inpatient expenditures (p = 0.03). When alcoholism clinic costs were excluded from combined inpatient and outpatient expenditures, significance was maintained over the 3 yr (p = 0.02). In combined inpatient and outpatient expenditures including alcoholism treatment costs, the dollar differential between groups was substantial but not statistically significant.

Alcoholism↗
PubMedDate not supplied

The human tumour-associated epithelial mucins are coded by an expressed hypervariable gene locus PUM.

A single highly-polymorphic autosomal gene locus PUM codes for a family of mucin-type glycoproteins, separable by SDS-gel electrophoresis, which we first identified in human urine. The locus also codes for glycoproteins which are abundant in several other normal epithelial tissues and body fluids, including milk, and in tumours of epithelial origin. These mucin-type glycoproteins seem to be very immunogenic in rodents and, in a search for epithelial specific or tumour-associated antigens, a large number of related antibodies have been isolated which bind to the PUM-coded mucins. Many of the antibodies show a pronounced tumour specificity on immunohistology and are being used widely in cancer diagnosis in vitro and in vivo and even in cancer therapy. To investigate the expression of these antigens in normal and malignant cells complementary DNA coding for the mammary mucin has been isolated. Here we present evidence obtained using this cDNA that the PUM locus is a hypervariable 'minisatellite' region of human DNA similar to those described by several groups, but which is novel in that it is transcribed and translated, and that the same polymorphism is demonstrable in the expressed gene product.

Base Sequence↗
PubMedDate not supplied

Expression of the hypervariable PUM locus in normal and malignant lung: the tumor-associated epitopes are present but masked in normal tissue.

A single highly polymorphic gene locus PUM codes for a family of mucin-type glycoproteins present in human urine. These glycoproteins can be detected after electrophoresis using a group of monoclonal antibodies which show marked tumour specificity on immunohistology and include the HMFG and Ca antibodies (Swallow et al., 1986, 1987). Here we show by electrophoretic analysis of lung specimens and urine samples from nine individuals, that the PUM locus is expressed both in malignant and in normal lung. In contrast immunohistology of frozen sections of normal lung showed very little staining using the same antibodies, occasional reactive type 2 pneumocytes alone staining, whilst the carcinoma material showed strong staining in each case. However, after formalin fixation much more staining was observed in normal lung, all type 1 and 2 pneumocytes being stained. These observations suggest a difference in accessibility of the epitopes in normal and malignant lung, rather than a difference in expression of the PUM gene.

Antigens, Neoplasm↗