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Biomedical subjects

A Edwards

Publications and source records attributed to A Edwards.

At least 271 records · Page 15Linked to original sources
PubMed1977

Luteinizing hormone and testosterone during nocturnal sleep: relation to penile tumescent cycles.

Variations of plasma LH and testosterone in relation to sleep-related penile tumescence were assessed. Plasma LH and testosterone were measured at 10-20 min intervals in five normal adult men during 2 nights of sleep. Blood samples were obtained by means of an indwelling venous catheter while sleep was monitored polygraphically and penile tumescence recorded with a penile mercury strain gauge. Tumescent episodes were recorded in all subjects during 9 of the 10 nights of the study, and the percentage of time during sleep, which was associated with tumescence, ranged from 13% to 34%. Simultaneous REM and tumescence comprised 57.7% of total tumescent time. Abrupt elevations of plasma LH and testosterone were observed during the night without a significant relationship to stages of sleep. The mean of all hormonal determinations for the five subjects did not show significant differences in plasma LH and testosterone between fully and partially tumescent episodes and nontumescent periods. Mean testosterone during REM sleep with tumescence, a state of autonomic activation involving sexual function, was consistently higher for the five subjects than during periods free from REM and tumescence.

Adult↗
PubMed1976

Antigens on melanoma cells detected by leukocyte dependent antibody assays of human melanoma antisera.

Antibody-dependent cell-mediated cytotoxic assays have been used to examine antigens on human melanoma cells obtained either directly from patients or from long-term melanoma cell lines. A panel of melanoma antisera was selected from human subjects which could be shown not to have significant reactivity to histocompatibility antigens. With these antisera extensive cross-reactions between melanoma cells were found. However, the cross-reactivity was incomplete and the pattern of reactivity was different for each antiserum tested. These results were not consistent with a common melanoma antigen on human melanoma cells but rather indicated heterogeneity of melanoma antigens and multiple antibody specificities in the sera tested. This appeared to be confirmed by extensive cross-absorption studies which indicated limited cross-reactivity of antigens on melanoma cells from either long-term or short-term cultures. Several changes in the antigenic profile of melanoma cells in vitro from both long-term and short-term cultures were documented which resulted from contamination of the melanoma cell lines with non-melanoma cells and fibroblasts. Melanoma antisera may therefore be useful to mintor changes in long-term cultures which would otherwise give spurious results in in vitro tests. These results appear to have considerable significance for understanding tumour/host relationships and for the establishment of rational immunotherapeutic procedures and diagnostic tests in melanoma.

Antibodies↗
PubMed1976

Antibody-dependent cell-mediated cytotoxicity against melanoma cells induced by plasmapheresis.

Patients with disseminated melanoma were treated by repeated plasmapheresis using a continuous-flow blood-cell separator, as part of a study to investigate methods of removing factors from tissue fluids which block cell-mediated immunity. Using 51Cr release cytotoxic assays, it was found that plasmapheresis resulted in removal of serum blocking activity. Post-plasmapheresis sera taken from several patients also increased cell-mediated cytotoxicity by induction of antibody-dependent cell-mediated killing. This effect may have resulted from removal or alteration of circulating immune complexes in the serum. It is not known whether cytotoxic activity induced in this way improves the patient's immune response against their tumours. However, the procedure is well tolerated and these preliminary in-vitro results indicate that this form of therapy could act as an adjunct to other forms of treatment of advanced melanoma.

Antigen-Antibody Complex↗
PubMed1976

Discussion paper: the use of glutaraldehyde fixation for the study of the immune response to syngeneic tumor antigen.

We have been able to demonstrate that glutaraldehyde fixation of tumor cells or tumor cell membrane fragments protect syngeneic mice against the subsequent challenge with viable cells. To date we have not been able to detect any antibody against the tumor cells in animals so immunized. The specificity of the response is not complete, although a major component of the protective effect of glutaraldehyde-treated tumor cells is immunologically specific.

Aldehydes↗
PubMed1976

Paroxysmal nocturanal hemoglobinuria and marrow failure treated by infusion of marrow from an identical twin.

An 18-year-old white Canadian male patient with paroxysmal nocturnal hemoglobinuria and refractory marrow failure received a marrow infusion from his normal identical twin brother without prior ablation of the patient's marrow by drugs or irradiation. After 2 years of follow-up, the patient is well with no evidence of clinical disease or significant hematological abnormality. The results suggest that normal marrow stem cells can have a selective advantage over the abnormal paroxysmall nocturnal hemoglobinuria clone.

Adolescent↗
PubMed1976

Characterization of mononuclear effector cells in human blood.

The effector cells responsible for cytotoxic activity induced by phytohaemagglutinin, (PHA) pokeweed mitogen (PWM) target cells complexes with IgG antibody has been investigated using cell separation techniques based on rosette formation and separation through Hypaque-Ficoll mixtures. It was shown the PHA-induced cytotoxicity is predominantly a function of T cells and that Fc receptor-bearing cells are not involved to any major extent. Antibody-dependent killing is conversely a function of Fc receptor-bearing cells among which two subtypes can be distinguished. One of these has receptors for activated complement while the other bears Fc receptors only and has no detectable receptors for complement. PWM appears to induce cytotoxicity in both T- and non-T-cell populations but the major cell type involved appears to be Fc receptor-bearing cells similar to those mediating antibody-dependent killing. It is concluded that PHA and antibody-dependent killing are the two most useful assays for discriminating between the cytotoxic activity of T and non-T cell in clinical studies.

Animals↗
PubMed1975

Comparison of 51Cr release and microcytotoxicity assays against human melanoma cells.

Comparisons of the cytotoxic activity of mononuclear cells from venous blood of human subjects against human melanoma cell lines have been made by means of the 51Cr release assay (CRA) and the microcytotoxicity assay (MCA) of Takasugi and Klein. The relative effectiveness of the two assays in the detection of killing by various sub-populations of effector cells was studied after depletion of monocytes and separation of the blood monocluear cells by SRBC receptor and Fc receptor resetting techniques. Overall, the results showed good correlation. Most differences were the result of low values recorded with the CRA when effector cells were obtained from Hypaque-Ficoll--separated populations which had not been further fractionated. These differences were largely removed when monocytes were depleted by glass absorption and may reflect interference with the CRA by monocytes. No consistent differences were found between the assays in the detection of killing by subfractions enriched for T cells or B cells in this tumour system. The MCA appears to offer the advantage of greater sensitivity and possibly detection of a wider range of cytotoxic mechanisms but the CRA has a number of advantages of a technical nature which make it more applicable to routine assays in clinical studies.

Antigen-Antibody Reactions↗
PubMed1975

Specificity of cell-mediated cytotoxicity against human melanoma lines: evidence for "non-specific" killing by activated T-cells.

The specificity of cell-mediated cytotoxicity against melanoma cells in vitro has been analyzed in a large number of studies with cells both from normal and melanoma subjects. As in a number of other, recent, similar human studies, no evidence for tumour specificity was found. Effector cells in peripheral blood responsible for the cytotoxic raction were examined by cell separation methods based on red cell rosette formation and separation through Hypaque-Ficoll mixtures. The evidence suggests that non-specificity results from killing by cells separating largely in the non-sheep red blood cell rosetting fraction and which have cytotoxic specificity directed broadly to cells with abnormal membranes. Further analysis revealed that the cells were non-phagocytic and did not bear receptors for complement. They appear to be activated into cell division and to bear surface receptors for the Fc portion of IgG. Additional evidence is presented suggesting that the cells mainly responsible are activated thymus-dependent cells present in the circulation of both tumour-bearing and normal subjects.

Antigen-Antibody Reactions↗
PubMed1975

The assessment of nocturnal REM erection in the differential diagnosis of sexual impotence.

A new method for differentiating psychogenic from organic cases of sexual impotence is described based on the assesst of nocturnal REM erection in nine patients. It is our tentative impression that in psychogenic impotence nocturnal REM erection may be normal in amount and degree and an excellent indicator of erectile potential. In these cases a marked discrepancy exists between the amount and degree of nocturnal erection and the patient's daytime performance level attained during attempted coitus or masturbation. In the organic patients, on the contrary, such a discrepancy does not exist; instead, the maximal nocturnal erection attained corresponds closely to and mirrors the patient's impaired waking performance. This new method may be very useful in the diagnosis, prognosis, and decision as to type of treatment, especially in difficult cases.

Adult↗
PubMed1975

Referral letters from general practitioners.

If continuity of care is to be preserved, then the process by which a patient is referred to hospital is important. We have analysed a series of letters of referral from general practitioners with special reference to the diagnoses made and the inclusion of a relevant history.

Communication↗