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Biomedical subjects

J Watson

Publications and source records attributed to J Watson.

At least 325 records · Page 18Linked to original sources
PubMed1980

Biochemical and biologic characterization of lymphocyte regulatory molecules. III. The isolation and phenotypic characterization of Interleukin-2 producing T cell lymphomas.

To isolate a stable tumor cell line source of Interleukin 2 (IL-2 formerly referred to as T cell growth factor), over 40 murine leukemia and lymphoma cells as well as 9 clonal helper and killer IL-2-driven T cell lines were screened for both constitutive and mitogen-stimulated IL-2 production. A radiation-induced splenic lymphoma from the B10.BR mouse, the LBRM-33 cell line, could be stimulated to produce over 1000 units/ml of IL-2 after 24 hr exposure to T cell mitogens. Peak IL-2 activity was found in supernatants harvested from 24-hr cultures of either 1% PHA or 20 micrograms/ml Con A-stimulated LBRM-33 cells (10(6) cells/ml). IL-2 production observed in both serum-free and serum-containing cultures represented between 1000 and 5000 times the quantity of IL-2 produced in conventional cultures of mitogen-activated rat or mouse spleen cells. Peak IL-2 production by LBRM-33 cultures (stimulated at either optimal Con A or PHA concentrations or co-stimulated with suboptimal amounts of mitogen and phorbol myristate acetate) was consistently accompanied by LBRM-33 cell death. Phenotypic characterization of the producer cell revealed LBRM-33 cells to be Thy 1+, Ly 1+, Ly 2+, Ly 3+, Qa 2-3+, Qa 3.2+, Qat 4+, and Ly 5+. These studies provide further evidence that IL-2 is a T cell product and establish a source of IL-2 that will be a valuable reagent for the isolation and further molecular characterization of this immunoregulatory molecule.

Animals↗
PubMed1980

Biochemical and biologic characterization of lymphocyte regulatory molecules. IV. Purification of Interleukin 2 from a murine T cell lymphoma.

A cloned murine T cell line, LBRM-33 5A4, growing in culture can be activated by phytohemagglutinin (PHA) to secrete Interleukin 2 (IL-2) activity. In the absence of PHA, LBRM cells do not produce IL-2. The chemical and biologic properties of LBRM-derived IL-2 are compared to those of murine spleen-derived IL-2. The fractionation of culture supernatants from PHA-activated LBRM cells by ion-exchange chromatography, gel filtration, and isoelectric focusing (IEF) reveals that IL-2 activity is contained in a class of molecules indistinguishable in size (30,000) and charge (pI 4.3-4.7 and 4.9-5.1) from murine spleen IL-2. LBRM-derived IL-2 also exhibits the entire spectrum of biologic activities exhibited by spleen IL-2, stimulating the growth of established T cell lines in culture, the generation of cytotoxic T lymphocytes in thymocyte cultures and the induction of antibody responses in nude spleen cultures. Both LBRM and splenic-derived IL-2 activities exhibit similar properties after digestion with proteases, and various chemical and temperature treatments. Since IL-2 is derived from a cloned cell line, it is likely these lymphocyte assays are detecting a single class of molecules that act directly on activated T cells. The use of LBRM cells as a source of IL-2 should greatly facilitate studies on the molecular characterization and biologic activity of this class of lymphocyte regulatory molecules.

Animals↗
PubMed1980

The effects of physical training on high level spinal lesion patients.

Seven chronically institutionalised high level spinal lesion subjects participated in an exercise program, five days per week for seven weeks. Anthropometry, spirometry and maximum oxygen consumption (VO2 max) was measured initially and at the end of seven weeks. Subjects generally followed a common training program. No significant changes were noted in the anthropometric and spirometric measurements. A significant increase (34%) in minute ventilation was recorded, and this was accompanied by significant increases in VO2 max 0.764 +/- 0.341 to 1.03 +/- 0.419 1 x min-1 (P less than 0.01) and wheelchair treadmill time 502 +/- 340 to 766 +/- 249 sec (P less than 0.05). The exercise program had no significant effect on maximum or recovery heart rates. Many subjects had subjective comments on improved psychological state. The significant changes in VV2 max, VE, and wheelchair treadmill time indicated that high level spinal lesion subjects can exhibit an improved cardiovascular function through regular aerobic exercise.

Adult↗
PubMed1980

Bioavailability of Lynestrenol.

The bioavailability of lynestrenol and ethynyloestradiol from a capsule formulation was superior to a normal tablet formulation. Bioavailability, as measured by the area under the plasma concentration curves, showed, particularly in the case of the capsule formulation, that all of the administered lynestrenol was converted to norethisterone.

Adult↗
PubMed1979

Continuous proliferation of murine antigen-specific helper T lymphocytes in culture.

Murine helper T cells activated to sheep or horse erythrocyte antigens in vivo have been established as continuous cell lines in culture. T cells require the presence of a T-cell growth factor (TCGF) for continuous proliferation. TCGF purified from murine, rat, or human sources all stimulate murine T-cell growth. The T-cell mitogens concanavalin A and phytohemagglutinin do not stimulate cell proliferation in continuous T-cell lines. All cells that grow in the presence of TCGF express Thy-1 antigens. Helper activity of T-cell lines is both antigen specific and effective for syngeneic or F1 B cells. Supernates from T-cell lines do not contain antigen-specific or nonspecific helper factors. Although several T-cell lines have shown stable helper activity for greater than 50 wk in culture, other cell lines have shown a gradual decline in effector function. The procedure used to establish and maintain proliferation of T cells in culture should be suitable for the selection and growth of antigen-specific effector T cells from each subclass.

Animals↗
PubMed1979

Biochemical and biological characterization of lymphocyte regulatory molecules. I. Purification of a class of murine lymphokines.

Murine spleen cells activated by concanavalin A (Con A) in culture produce a class of lymphokine molecules which possess biological activity in a number of lymphocyte response assays. Lymphokines with a mol wt of 30,000, as estimated from gel filtration studies, can be resolved into two components which differ by charge, with isoelectric point (pI) values of 4.3 and 4.9, respectively. Both components stimulate (a) the growth of established T-cell lines in culture, (b) the proliferation of thymocytes in the presence of Con A under culture conditions where Con A alone is nonmitogenic, (c) the induction of antibody responses to heterologous erythrocyte antigens in athymic (nude) spleen cultures, (d) the generation of cytotoxic T lymphocytes (CTL) in thymocyte cultures, and (e) the generation of CTL in nude spleen cultures. In each of these culture systems we suggest that the assays are detecting a single class of lymphokine which acts directly on activated T cells. Nonactivated T cells must be stimulated by either antigen or mitogen before becoming responsive to lymphokine, but do not require antigen or mitogen for continued growth with lymphokine. The two molecular species, separable by isoelectric focusing are referred to as the T-cell growth factor (TCGF). A lymphokine, similar in size (30,000 daltons) to TCGF but heterogeneous in charge (pI 3.0--4.0), stimulates immune responses to erythrocyte antigens in T-cell-depleted spleen cultures but has no stimulatory activity in the other lymphocyte assay systems described. The data have been interpreted as showing the two molecular forms of murine TCGF (pI 4.3 and 4.9) are responsible for many of the lymphokine activities described elsewhere as thymocyte mitogenic factor, nonspecific T-cell-replacing factor and killer helper factor or costimulator. The other lymphokine, separable from TCGF by charge, appears to have true T-cell-replacing activity.

Animals↗
PubMed1979

Genetic control of the immune response to collagen. II. Antibody responses produced in fetal liver restored radiation chimeras and thymus reconstituted F1 hybrid nude mice.

The level of antibody produced in response to calf skin collagen in mice is influenced by genes which are closely linked to the I region of the H-2 major histocompatibility complex. This influence is shown to be expressed during lymphoid maturation by testing the antibody responsiveness to collagen in two types of chimeric mice. First, high responder and low responder parental strain mice were lethally irradiated and restored with fetal liver cells from (high X low responder) F1 mice. These F1 leads to parent chimeras exhibited an immune response phenotype characteristic of the irradiated parental strain animals, establishing that H-2 determinants of the host affect antigen responsiveness. Second, (high X low responder) F1 congenitally athymic (nude) mice were restored with fetal thymus transplants from either high or low responder parental strain mice. After a period of maturation these mice were shown to be competent for a T-dependent IgG response to SRBC. The responsiveness to collagen in these mice was characteristic of the parental strain thymus donors, indicating that the expression of H-2 determinants in thymic tissue during lymphoid maturation influences the antibody response phenotype expressed by mice.

Animals↗
PubMed1979

Effect of oestradiol-17 beta and gonadotrophins on prostaglandin production by pre-ovulatory pig follicles superfused in vitro.

Pre-ovulatory pig follicles were superfused in vitro with oestradiol, LH or FSH in the presence and absence of indomethacin. Prostaglandin E2 ANd F2 alpha and oestradiol were measured in the same samples of superfusate. LH and FSH caused an increase in levels of both prostaglandins (approximately 2-fold) but the most marked effect was of oestradiol in PGE2 where a 4-fold increase in levels above controls was observed. In all cases indomethacin inhibited the effects. Both gonadotrophins caused an increase in oestradiol production although the response to LH was much slower than to FSH. The results show a possible relationship between FSH, oestradiol and PG synthesis in the pre-ovulatory pig follicle.

Animals↗
PubMed1979

Prostaglandin E-2-9-ketoreductase in ovarian tissues.

The existence of the enzyme prostaglandin E-2-9-ketoreductase which can convert prostaglandin E-2 to prostaglandin F-2 alpha was indicated in experiments with pig and human ovarian tissues in vitro, using radioimmunoassay methods and a superfusion technique. Further studies involving radiotracer techniques demonstrated that the enzyme was localized in the high-speed (105 000 g) supernatant fraction of human, pig and rat luteal tissue and human stromal tissue. The enzyme was shown to be NADPH-dependent and its activity in luteal tissue increased in the order : pig less than human less than rat.

Animals↗
PubMed1979

Steroid and prostaglandin secretion by the corpus luteum, endometrium and embryos of cyclic and pregnant pigs.

Prostaglandin F2 alpha (PGF2 alpha) secreted by the reproductive tissues of the pig in vitro was measured and it was found that the levels secreted by the corpus luteum and endometrium of early pregnant sows were significantly lower than those secreted by tissues during the late stage of the oestrous cycle. They were, however, comparable to levels secreted by tissues from the mid-stage of the oestrous cycle. Embryos also secreted significant amounts of PGF2 alpha. Secretion of progesterone and oestradiol by the corpora lutea of both cyclic and pregnant pigs fell within accepted limits but embryos were also found to secrete significant amounts of oestradiol. The results suggest that luteal maintenance in the early pregnant pig is unlikely to be directly due to reduced synthesis of PGF2 alpha.

Animals↗