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Biomedical subjects

J Morgan

Publications and source records attributed to J Morgan.

At least 271 records · Page 15Linked to original sources
PubMed1984

HeLa cells form focal contacts that are not fibronectin dependent.

HeLa cells cultured on glass substrata produce numerous prominent focal contacts, which reside at the termini of actin microfilament bundles. However, very few of the cells stain for fibronectin with specific anti-fibronectin antibody. Moreover, the cells form focal contacts in fibronectin-depleted medium, in the presence of high concentrations of anti-fibronectin immunoglobulin G and in the presence of monensin. No fibronectin synthesis can be detected by [35S]methionine-labelling and immunoprecipitation. The possibility that HeLa cell focal contacts are independent of fibronectin in their formation is discussed in relation to the controversy about the relationship between fibronectin and focal contacts.

Animals↗
PubMed1984

Lymphokines and monokines as regulators of human lymphoproliferation.

The development of a competent immunoregulatory response in the face of an antigenic challenge is modulated by soluble proteins of relatively low molecular mass. Lymphokines and monokines, secreted by cells of T lineage and cells of the monocyte/microphage series, respectively, function in a bimodal amplification network that results in the proliferation and differentiation of the immunoregulatory cells. Interleukin 1 is typically assayed by its effect on thymocytes or by its ability to promote the T cell-dependent release of interleukin 2. Interleukin 2 is routinely measured by its ability to support the long-term growth of cultured T cells, whereas B cell growth factor is measured by its ability to support the long-term growth of cultured B lymphocytes. The availability of homogeneous purified factors and the subsequent availability of monoclonal antibodies against these reagents should allow for the development of rapid quantitative assays for these analytes in diverse biological fluids. In addition, large quantities of purified reagents will promote studies to determine therapeutic efficacy in several immunodeficiency syndromes.

B-Lymphocytes↗
PubMed1984

Fast walking velocity in health and Duchenne muscular dystrophy: a statistical analysis.

Fast walking velocity was measured in 335 apparently healthy subjects, 180 males and 155 females, whose ages ranged from 3.5 to 24 years. These velocities increased with age and approached an asymptote of 3.44m/sec in males and 3.17 m/sec in females, a statistically significant difference (p less than 0.001). This parameter was also measured serially over periods of 18 to 132 months in 15 patients with Duchenne muscular dystrophy. A decrease in walking rate began between ages four and six. This decline was found to fit linear and monoexponential decay mode models equally. Average linear decay for all 15 patients was 0.0308 m/sec/month; and the average fractional decay was 0.0349/month. On average, by 10 years, the fast walking rate was reduced to about 29% of normal. This measure of disease progression followed a unique course in each subject, which could be mathematically characterized by a unique decay rate, and a unique walking velocity at age 10 years. Thus, in contrast to natural speed walking, the measurement of fast walking velocity has proved to be a simple and useful index for characterizing disease progression in Duchenne muscular dystrophy, and for evaluating therapeutic interventions.

Adolescent↗
PubMed1983

Acute and chronic immunological response to dietary antigen.

On separate mornings at 14 day intervals groups of six to eight healthy fasting male volunteers drank a 5.5 MJ test meal containing 20% milk, egg or soya protein, or a control protein free preparation. Using a Clq binding test, marked but transient rises in circulating immune complexes were detected 30-120 minutes after the milk and egg meals but not with soya or the control. No such changes were seen when complexes were measured by Raji cell immunoassay. Food antigen specific antibodies were present in the plasma of all subjects but showed no consistent pattern of variation in the postprandial period. In most volunteers a chronic increase in milk (three weeks) or soya (six weeks) consumption produced no changes in circulating immune complexes or antibodies to dietary protein. Although two of 16 milk and six of 52 soya volunteers had substantial rises of one or more classes of plasma food antigen specific antibodies they were matched by a similar number in which a decrease was recorded. These results indicate that the formation of circulating immune complexes may be a physiological response to a large load of dietary antigen but that in most adults a chronic increase of milk or soya consumption does not affect food antibody or immune complex concentrations.

Adult↗
PubMed1983

Proliferation of human B lymphocytes mediated by a soluble factor.

Recent studies have established the ability of a proportion of activated human B lymphocytes to undergo G1 phase cell cycle progression and subsequent S phase entry on exposure to factor(s) present in lectin-stimulated mononuclear cell-conditioned media. One factor capable of stimulating activated human B lymphocyte proliferation may be separated from peripheral blood lymphocyte-conditioned media by successive ammonium sulfate precipitation, ion exchange, and gel filtration chromatography. The isolated factor is distinct from the other well-described cytokines, possesses a molecular weight of 12,000-13,000, has a mildly acidic isoelectric point (at pH 6.3-6.6), is protease sensitive, and is relatively heat sensitive. The human B cell mitogenic factor possesses functional and cellular specificity in that its action is restricted to B lymphocytes and its function is proliferative. The production of the B cell mitogenic factor by T lymphocytes is augmented by the presence of a macrophage and further stimulated by syngeneic B cells.

B-Lymphocytes↗
PubMed1983

Serovar identification of leptospires of the Australis serogroup isolated from free-living and domestic species in the United Kingdom.

Eighteen isolates from the Australis serogroup from free-living and domestic animals were identified using the cross agglutination absorption test. Serovar muenchen was found only in England and Wales in wood mice, short tailed and bank voles, a grey squirrel and a pig. Serovar bratislava was found in hedgehogs in England, Wales and Northern Ireland and also in a brown rat from Northern Ireland. Serovar bratislava was isolated from sheep in both England and Northern Ireland and from horses in Northern Ireland. The distribution of these serovars in relation to possible maintenance hosts is discussed.

Agglutination Tests↗
PubMed1983

Absence of pH effect on creatine kinase leakage from mouse skeletal muscle.

Skeletal muscle enzyme leakage has been found to be independent of extracellular pH (6.6 - 8.2), changes in ionic strength, osmolarity, and the weight changes that occur during in vitro incubation. This is in contrast to the effect of pH and ionic strength on heart, and no change in heart weight, during incubation in similar media. These observations further emphasize the disparate responses of heart and skeletal muscle to changes in the extracellular environment.

Animals↗
PubMed1982

Antibody-dependent cell-mediated cytotoxicity in human cancer: characterization of patient leukocyte activity and treatment effects.

Antibody-dependent cell-mediated cytotoxicity (ADCC), medicated by peripheral blood Hypaque-Ficoll separated mononuclear cells, was studied in humans using chicken erythrocytes (CRBC) incubated in a 1:1200 dilution of rabbit anti-CRBC and human B erythrocytes (HRBC) incubation in a 1:20 dilution of isoantibody. At the optimal target effector ratio of 3:1, ADCC to both CRBC and HRBC was significantly higher than normal in 27 lung cancer, 18 malignant melanoma, and seven colon cancer patients, but not in 20 breast cancer patients. Chemotherapy (single-agent or combination) in 12 patients did not effect ADCC in vitro but significantly suppressed ADCC to both targets after only four or five days of therapy in vivo (ADCC to CRBC, 47.4 to 24.1% lysis: ADCC to HRBC, 48.1 to 16.3% lysis). Immunotherapy with intravenous (IV) corynebacterium parvum or IV methanol extraction residue of BCG (MER) boosted ADCC to both targets within four to seven days of the first dose. It was found that ADCC to HRBC but not to CRBC was completely absent in three cases of active hairy cell leukemia but was present in two cases in remission. The ADCC to HRBC showed an age-dependent increase in both the 51 normal subject and the cancer patients. This was not observed for ADCC to CRBC. The ADCC to CRBC was mediated mainly by an Fc-receptor-positive, nonadherent, small lymphocyte, and ADCC to HRBC was mediated entirely by an adherent monocyte. The ADCC did not correlate significantly with the H3 thymidine incorporation of peripheral blood mononuclear cells, cultured without stimulation for either one or seven days. It also did not correlate with the number of residual granulocytes in the mononuclear cell suspensions. Measurement of ADCC is a useful method of characterizing host defense in malignant disease and its modification by therapy.

Age Factors↗
PubMed1982

Synthesis of thymosin beta 4 by peritoneal macrophages and adherent spleen cells.

Thymosin beta 4, previously identified as a component of thymosin fraction 5 isolated from calf thymus, is synthesized by peritoneal macrophages derived from rats or mice, including cells from nu/nu mice. Identification of thymosin beta 4 containing [35S]methionine was based on its retention time in reverse-phase HPLC and the recovery of radioactivity in peptides generated by mild acid hydrolysis or by digestion with trypsin. Thymosin beta 4 is also synthesized by rat and mouse spleen cells, and evidence is presented for its release from these cells.

Animals↗
PubMed1982

Biochemical separation of a human B cell mitogenic factor.

Recent studies have established the ability of human B lymphocytes to undergo G1-phase cell cycle progression and subsequent DNA synthesis upon exposure to factor(s) present in media conditioned by lectin-stimulated mononuclear cells. Procedures for the isolation of such a cytokine have been the focus of the present investigation. Conditioned medium from cells stimulated by lectin for 72 hr was fractionated by ammonium sulfate precipitation, ion-exchange chromatography, and gel filtration chromatography. During the isolation procedure the proliferation-stimulating activity of the column fractions was assayed concurrently on purified human T cells, purified human B cells, and murine thymocytes. T cell and B cell stimulatory factors present in the initial conditioned medium were found to copurify during ammonium sulfate precipitation, DEAE-Sephadex chromatography, and Bio-Gel P-30 gel filtration. However, partial separation of these two activities was achieved after Bio-Gel P-100 gel filtration. Analytic polyacrylamide gel electrophoresis of radiolabeled Bio-Gel P-100 column fractions demonstrated a distinct protein band of 14,000-15,000 daltons in those column fractions predominantly supporting T cell growth and a distinct protein band of 12,000-13,000 daltons for those fractions predominantly supporting B cell growth. The fractions associated with B cell mitogenic activity induced B cell S-phase entry in a proportion of B lymphocytes in the absence of any detectable IgM secretion.

B-Lymphocytes↗
PubMed1982

Thymosin beta 4: a ubiquitous peptide in rat and mouse tissues.

Thymosin beta 4, recently isolated from calf thymus, is present in a number of rat and mouse tissues, including spleen, thymus, brain, lung, liver, and heart muscle. High concentrations are found in peritoneal macrophages, suggesting that its occurrence in other tissues may be related to the presence of macrophages or macrophage-like cells in these tissues. The conclusion that "thymosin" beta 4 does not originate solely in the thymus gland is supported by the high concentrations found in tissues of athymic (nu/nu) mice.

Animals↗