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Biomedical subjects

J Robinson

Publications and source records attributed to J Robinson.

At least 469 records · Page 26Linked to original sources
PubMed1981

Epstein-Barr viral DNA: infectivity for human placental cells.

Purified DNA of Epstein-Barr virus (EBV) is regularly infectious by means of the "calcium" method of transfection. Cultured human placental cells exposed to EBV DNA of two transforming strains, FF41 and B95, produce virus that is capable of converting normal B lymphocytes into established cell lines. After treatment with EBV (FF41) DNA and EBV (HR-1) DNA the placental cells display antigens associated with the productive viral cycle. The placental cells have not developed foci or other signs of morphologic transformation.

Antigens, Viral↗
PubMed1981

Expression of cell-surface HLA-DR, HLA-ABC and glycophorin during erythroid differentiation.

The unexpected discovery that Ia-like (HLA-DR) antigens in humans were present on blast cells from acute myeloblastic leukaemia led to the finding that normal granulocytic progenitors, in contrast to their mature descendents, also expressed HLA-DR antigens. Thus, anti-Ia sera stain a proportion of myeloblasts in normal bone marrow, inhibit myeloid progenitor (CFU-GM) colony formation in the presence of complement and can be used to label and separate CFU-GM on a fluorescence-activated cell sorter (FACS). Winchester et al. subsequently reported that erythroid progenitors (BFU-E and CFU-E) were also inhibited or killed by anti-Ia (p28,37) and complement. These observations raised the possibility that HLA-DR (or presumptive I-region equivalent) products might have a regulatory role in early haematopoiesis. We have now analysed HLA-DR and HLA-ABC antigen expression on normal erythroid progenitors using monoclonal antibodies to non-polymorphic determinants and fluorescence-activated cell sorting. In parallel experiments, we tested a monoclonal antibody to glycophorin, a well defined erythroid-specific cell-surface membrane glycoprotein. We report that HLA-DR, HLA-ABC and glycophorin are all expressed at various stages during erythroid differentiation.

Bone Marrow↗
PubMed1981

Mapping cell surface antigen expression of haemopoietic progenitor cells using monoclonal antibodies.

A library of monoclonal antibodies which show selective reactivity with particular cells or gene products (e.g. HLA-DR, glycophorin) of different cell lineages in the haemopoietic system has been compiled. Using these probes in conjunction with the fluorescence-activated cell sorter (FACS) the pattern and sequence of cell surface antigenic expression on haemopoietic progenitor cells have been mapped. A cell is identified in bone marrow which has a unique membrane phenotype and the nuclear enzyme terminal deoxynucleotidyl transferase. Its composite phenotype is identical to that seen in the common variant of acute lymphoblastic leukaemia (ALL). It is suggested that this cell is a putative B lineage progenitor which provides the major target for ALL. Detailed analysis of erythroid differentiation with monoclonal antibodies on the FACS reveals an intriguing pattern of antigenic expression in which HLA-DR, glycophorin and band III appear in sequence. HLA-DR (Ia-like antigen) may be present on all or most committed haemopoietic progenitor cells and could play an important role in cell interactions regulating early haemopoiesis.

Animals↗
PubMed1981

The relationships between clinical response, psychophysiological variables and plasma levels of amitriptyline and diazepam in neurotic outpatients.

In a 4 week study of the response of neurotic outpatients to treatment with amitriptyline, diazepam, amitriptyline and diazepam, or placebo clinical and psychophysiological variables and plasma levels of the drug were assessed. Clinical improvements were substantial in all treatment groups but clear relationships between clinical change, psychophysiological change and plasma levels of the drugs were not established. There was no relationship between plasma levels of the drugs and cigarette smoking. It is concluded that neither plasma levels of amitriptyline and diazepam nor change in skin conductance responsivity offer a useful guide to clinical response to drug treatment.

Adult↗
PubMed1981

Exotoxins of Aeromonas hydrophila.

Eighty of 103 strains of Aeromonas hydrophila cultured at 100 rev./min produced heat-labile enterotoxins detected using the suckling mouse assay. Results in intestinal perfusion agreed with the suckling mouse test in all strains tested by both methods. Enterotoxic activity correlated with haemolysin and cytotoxin production, but 4% of strains would have been wrongly classified using haemolysin assay in place of the suckling mouse test and 11% misclassified on the basis of cytotoxin assay. There was a significant association between haemolytic and cytotoxic activity, but 15% of strains produced only one of these toxins. Haemolysin, cytotoxin and enterotoxin were not always associated in a given isolate. The time of appearance of exotoxins during bacterial growth and the effects of dialysis, heating and proteolytic enzymes also suggest that haemolysins, cytotoxins and enterotoxins of Aeromonas hydrophila are separate toxins and not different manifestations of the same toxin.

Aeromonas↗
PubMed1981

Resistance of neonatal human lymphoid cells to infection by herpes simplex virus overcome by aging cells in culture.

Mononuclear leukocytes freshly harvested from human umbilical cord blood were refractory to infection by herpes simplex virus (HSV) type 1, whereas cells aged in vitro for a week produced 10- to 100-fold or greater more virus. Increased sensitivity of aged cells to infection by HSV was not dependent on active DNA synthesis by the cells at the time of exposure to HSV. The aging phenomenon was not due to the outgrowth of a specific cell subpopulation that is uniquely susceptible to HSV because increased sensitivity to HSV type 1 occurred in a variety of cell subpopulations enriched or depleted of T lymphocytes, phagocytic cells, or adherent cells. About 25% of aged cells contained virions detectable by electron microscopy, considerably more cells than formed infectious centers. These virions were seen in large activated lymphocytes which are the principal cell subpopulation present in the aged cultures, but virions were also seen in small lymphocytes.

Animals↗
PubMed1981

Detection of enterotoxins of Aeromonas hydrophila by a suckling-mouse test.

The suckling-mouse assay was reliable for detecting enterotoxigenic strains of Aeromonas hydrophila when standard conditions for growth and toxin testing were used. Enterotoxins were produced by bacteria grown in tryptone soya broth supplemented with yeast extract and aerated by shaking in an environmental incubator or water bath. When culture supernates together with dye were administered intragastrically to mice less than 6 days old, the presence of enterotoxin was assessed on the basis of a scoring system that incorporated the ratio intestinal weight: remaining body weight, and production of diarrhoea. This method should facilitate the detection of enterotoxigenic strains of Aeromonas in epidemiological studies.

Aeromonas↗
PubMed1981

Dynamics of progesterone metabolism in the pseudopregnant rat.

The characteristics of the disappearance of progesterone and 20 alpha-dihydroprogesterone from blood were examined in rats made pseudopregnant by administration of gonadotrophins. Measurement of the disappearance of [3H]progesterone from blood indicated that progesterone metabolism can be represented by a two-compartment model in this animal preparation. The disappearance of [3H]progesterone from blood was described by two half-lives of 0.5 and 11.7 min. The metabolic clearance rate for this steroid was 2.9 litre/day, equivalent to a production rate of 3.9 mumol/day. The initial volume of distribution of the injected [3H]progesterone was 5.0 ml, a volume similar in size to the expected plasma volume. The total volume of distribution of [3H]progesterone (i.e. 'inner' and 'outer' pools) was in the range 24.8-35.4 ml. The disappearance of endogenous progesterone from the blood of pseudopregnant rats after vascular isolation of the ovaries showed two half-lives of 1.1 and 11.4 min respectively. The disappearance of a product of reductive metabolism of progesterone, 20 alpha-dihydroprogesterone, was apparently uniphasic, with a half-life of 41.3 min.

20-alpha-Dihydroprogesterone↗
PubMed1981

Exploitation of monoclonal antibodies: a "who's who" of haemopoietic malignancy.

A library of monoclonal antibodies plus "conventional' markers (e.g. anti-TdT) have been used to explore the detailed phenotypes of leukaemic cells in relation to normal haemopoietic differentiation. This analysis reveals that consistent, composite phenotypes of different subclasses of lymphoid malignancies closely mimic those of corresponding normal cells at equivalent levels of maturation. It is suggested that three major target cell populations are available for lymphoid malignancy: the pluripotential stem cell (e.g. "lymphoid' blast crisis of CGL), lymphoid progenitors or stem cells in the bone marrow (non-T ALL) or thymus (T-ALL, T-NHL) and long lived, mature and immunocompetent T and B cells (T-CLL, PLL, Sézary and B-CLL, lymphoma respectively). The major phenotypes documented in different leukaemias represent the level of "maturation arrest' imposed on the dominant subclone; this is determined by, but not necessarily synonymous with, the "target cell' and associated clonogenic cell population in the leukaemia. No consistent major abnormalities of gene expression are revealed by this investigation and although they may exist (e.g. loss or acquisition of antigens with malignant progression) we suggest that they are irrelevant to the central issue of what alterations are essential and sufficient for the evolution of clonogenic leukaemic cells. We propose instead that subtle changes, which uncouple proliferation and differentiation, are all that is required.

Antibodies, Monoclonal↗