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Biomedical subjects

S Joseph

Publications and source records attributed to S Joseph.

At least 181 records · Page 10Linked to original sources
PubMed1984

The fetus as an allograft: evidence for antiidiotypic antibodies induced by pregnancy.

We tested sera from 20 women [9 parous, 8 with no children, and 3 with abortion(s)] for inhibition in mixed lymphocyte culture (MLC). In these experiments, the responder (wife) lymphocytes were treated with autologous serum and rabbit complement and then tested for responses against stimulator cells from the husband and from third-party allogeneic donors. The results demonstrate that antibodies capable of inhibiting responses of wife's lymphocytes to husband's cells in MLC are present in sera from parous women, but not in women without children and in women with abortion(s). The MLC-inhibiting activity in parous women sera was in the IgG fraction. The results from immunofluorescence and absorption experiments suggest that the inhibition in MLC was due to antibodies directed against recognition sites on wife's T lymphocytes against husband's alloantigens. These observations suggest that antiidiotypic antibodies against husband-specific idiotypes on wife's lymphocytes could be induced by pregnancy and that maternal tolerance to fetus may be attributable to a similar mechanism occurring in vivo.

Abortion, Spontaneous↗
PubMed1983

Induction of antibodies by blood transfusions capable of inhibiting responses in MLC.

B6AF1 (H-2KbkDbd) mice were transfused weekly with 0.1 ml of whole blood from DBA/2 (H-2d) mice. One week after each transfusion, the mice were bled and the sera were collected and pooled. The presence of antiidiotypic antibodies in these sera was investigated using the mixed-lymphocyte culture (MLC) inhibition test, in which spleen cells from normal B6AF1 mice were treated with sera from transfused B6AF1 mice, washed, and then tested for their responses to DBA/2 stimulator cells. The sera collected following 3 and 4 transfusions caused a significant inhibition of responses in MLC, but sera obtained after 1 and 2 transfusions caused little or no inhibition. This inhibition was specific for stimulator cells from the blood donor (DBA/2) and was not observed against third-party SJL (H-2s) stimulator cells. In addition, the suppressive effect in MLC was specific for responder cells from the recipient B6AF1 mice, and no suppression was observed with responder cells from C3H (H-2k) and SJL mice. Treatment of DBA/2 stimulator cells with the serum caused no inhibition in MLC. The MLC inhibitory activity of the serum decreased gradually from the first to the third week following 4 transfusions, although a significant inhibition was still demonstrable after 3 weeks. These findings suggest that multiple blood transfusions induce antiidiotypic antibodies that can block the T cell antigen-specific receptors and cause suppression of the recipient's responses against the donor's alloantigens in MLC.

Animals↗
PubMed1983

Refractometry of fungi.

Immersion refractometry is based on matching the refractive index of the medium to that of the cytoplasm of the cell, in which case the latter will have minimum contrast in the phase contrast microscope and will practically disappear. The cytoplasm is then said to be at the match point with the medium. Since the refractive index of a solution is related to its concentration by the formula n-no equal alpha C, the values for the refractive indices can be expressed in terms of the concentration of solids (g/100 ml) which in fact has been done throughout this work. The properties of a suitable immersion medium, its preparation and interpretation of numerical results have been discussed. Refractometric measurements were carried out on fungal hyphae and spores. The solid concentration in hyphae varies according to their age, physiological state and function. In general the highest values are found at sites of physiological activity, such as growth and reproduction, and may range from 11% to 30% of solid concentration. The solid concentration of mature, resting spores was found to be in the range of 45-54%, with the exception of a powdery mildew spores in which the concentration of solids was 30-32%. The germination of spores is preceded by a fall in the concentration of solids, and subsequent swelling before the emergence of the germ tube. When the solid concentration in pre-germinating spore has fallen to about 20-30%, metabolic activity can take place and germination can occur.

Fungi↗
PubMed1982

Role of blood transfusions on the induction of antibodies against recognition sites on T lymphocytes in renal transplant patients.

We have tested sera from 23 renal allograft recipients to study the effects of blood transfusions on the induction of antibodies directed against recognition sites on T lymphocytes. The results demonstrate that antibodies capable of inhibiting responses in MLC could be induced by blood transfusion. This inhibition in MLC is observed by treatment of responder lymphocytes with serum plus rabbit complement and is mediated by IgG antibodies. Also, the inhibitory effect is specific for certain responder cells and is not mediated by antibodies against common surface antigens of either the responder or the stimulator lymphocytes. The antibodies inhibiting proliferative responses in MLC against antigens present on the kidney donor were demonstrable in renal transplant recipients with functional allografts, but not in patients who had rejected the graft. The data suggest that antibodies directed against recognition sites on T lymphocytes could be induced by blood transfusions and these antibodies may be associated with prolonged graft survival.

Autoantibodies↗
PubMed1981

Fat accumulation in the rat heart during fasting.

Following a short period of fasting, with free access to water, lipid droplet accumulation (LDA) occurs in many glandular organs as well as in the heart of several species. The present work describes the changes in the hearts of male and female rats of different ages (6, 12, 18 and 24 weeks) deprived of food for 1, 2 and 3 days. LDA was demonstrated by staining with Oil Red O and a special "scoring" system was developed based on sections arbitrarily divided into five regions for each ventricle and two for each atrium. Three standard sections were studied from each heart. This system largely avoided problems arising from the uneven distribution of fats in different parts of the heart. In control animals very little fat was seen in any part of the heart. The pattern of changes was similar in males and females but the degree of LDA was usually much greater in the male. In both sexes LDA increased after 1 day and usually reached a peak by the second day, followed by a sharp decrease, returning to almost normal. However in both sexes the response in the 18-week-old animals was minimal, with no clear peak. The LDA was always maximal in the R ventricle, followed by the L ventricle. The heaviest deposition occurred in the superior parts of the ventricles, close to the atria. LDA was comparatively rare in the atria. Fat appeared to be retained longest in the most heavily loaded regions. Recovery from LDA was rapid, being almost complete 24 hr after returning to a normal diet. Again the most heavily loaded regions retained fat longest. These findings are discussed in related to possible anatomical factors such as the distribution of blood vessels. It is unlikely that such factors offer an adequate explanation abd it is suggested that since the uptake of fats into the heart is probably controlled by lipoprotein lipase the distribution of this enzyme in difference parts of the heart should be investigated. The histochemical changes are also discussed in relation to previous biochemical work. Finally it is pointed out that it is common procedure to fast experimental animals overnight and even such a brief period could bring about considerable histological and metabolic changes.

Age Factors↗
PubMed1981

Role of the ABO, Secretor, and Lewis determinants in the primed lymphocyte test.

The antigenic determinants of the combined ABO, Lewis, and Secretor genes have been detected on the surface of lymphocytes by the lymphocytotoxicity test. We have studied the role of these determinants in the primed lymphocyte test (PLT), and the data demonstrate that Lewis incompatibility causes proliferative responses in PLT. On the other hand, no effects of ABO and Secretor incompatibilities were observed in this test. The frequency of the alloantigen-reactive cells (ARC) responding to Lewis and HLA-DR antigens in PLT was estimated by the limiting dilution analysis. The frequency of ARC to allogeneic Lewis-negative donors, who are positive for the sensitizing HLA-DR antigens ranged between 1:58 and 1:97. The incidence of ARC to Lewis-positive allogeneic donors who did not carry the sensitizing HLA-DR specificity was 1:94 to 1:142. These results demonstrate the presence of lymphocyte clones that are able to respond to antigens of the Lewis system. This study suggests that non-HLA antigens belonging to the Lewis system can cause stimulation of lymphocytes in the PLT test.

ABO Blood-Group System↗
PubMed1980

Limiting dilution analysis of alloantigen-reactive cells which respond to allogeneic lymphocytes in human MLC and PLT.

We have determined the frequency of the alloantigen-reactive cells (ARC) in human MLC and PLT by the limiting dilution analysis. In PLT, the frequency of the ARC to the original sensitizing donor ranged between 1:32 to 1:62, an increase of six to nine-fold after priming in MLC. The MLC primed populations were also enriched (three to five fold) for the ARC responding to the PL-positive allogeneic donors. The incidence of the ARC was 1:62 to 1:118 with donors positive for the sensitizing HLA-DRw antigen and 1:77 to 1:144 with donors negative for the specific HLA-DRw determinant. The results from experiments utilizing pooled stimulating cells from the original and allogeneic donors suggest that same subpopulation of cells responds to the sensitizing HLA-DRw determinant, whether it is presented by the specific stimulator or by a third-party allogeneic donor. On the other hand, different subpopulations of alloreactive cells respond to different alloantigens. In MLC experiments between HLA-identical siblings, the incidence of the ARC ranged between 1:995 to 1:1673. The responses of the ARC to non-HLA antigens were observed under conditions where responder cells were limiting. Also, the responses of the limiting numbers of responding cells were inhibited by mitomycin-treated autologous lymphocytes. Nonresponse in MLC combinations with higher responder cell numbers was not due to small numbers of stimulating cells.

HLA Antigens↗
PubMed1980

Exercise testing after beta-blockade: improved specificity and predictive value in detecting coronary heart disease.

The value of exercise testing in detecting myocardial ischaemia resulting from coronary atheroma remains controversial. In order to increase the reliability of exercise testing, all its components (asymptomatic, haemodynamic, and electrocardiographic) have been scrutinised. In this study, concerned only with the electrocardiographic response to exercise, the incorporation of beta-blockade into the standard exercise procedure has improved specificity and predictive value without affecting sensitivity. Fifty patients with anginal pain and 50 asymptomatic subjects with an abnormal electrocardiogram were investigated by exercise testing before and after beta-blockade (oxprenolol). All subjects had coronary arteriograms and left ventriculograms, and the results of exercise testing were related to the presence or absence of obstructive coronary artery disease. Possible causes of false positive exercise tests were eliminated by echocardiography. Though beta-blockade was unreliable in distinguishing ischaemic from non-ischaemic resting electrocardiograms, it eliminated all the false positive electrocardiographic responses to exercise in both groups and did not abolish any of the true positive electrocardiographic responses. Thus, specificity and predictive value were improved without reduction in sensitivity. This technique may not necessarily be applicable to other groups of patients or to a random population, but the results of this study suggest it will be a useful additional routine procedure in the investigation of coronary heart disease.

Adolescent↗
PubMed1979

Electrocardiographic changes resembling myocardial ischaemia in asymptomatic men with normal coronary arteriograms.

T wave and ST segment abnormalities in 20 asymptomatic men aged 18 to 55 were investigated because they were identical with myocardial ischaemic changes, and the professional livelihood of the subjects was jeopardised. Coronary arteriograms showed unobstructed arteries in all except one in whom a 50 per cent lesion of the left anterior descending artery was present. Left ventricular angiograms showed a normal contraction pattern, Ejection fractions were normal in 12 and increased in 8. Three characteristic electrocardiographic patterns were observed: flat or inverted T waves in leads II, III, aVF, and V4 to 6 designated type 1; deep T inversion particularly evident in leads V2 to 5 designated type 2, and minor ST segment depression in the inferior and lateral leads without T changes designated type 3. Characteristically, type 1 changes were temporarily suppressed by either beta-blockade or an overnight rest and were more abnormal in the standing position. Type 2 and 3 changes were relatively uninfluenced by these manoeuvres. Maximal treadmill exercise tests were positive in 6 and borderline or negative in 14. When repeated after oxprenolol all tests were negative. Echocardiograms showed asymmetric septal hypertrophy in 3 subjects (ratio of greater than 1.5 between ventricular septum and posterior left ventricular wall). After normalisation by an overnight rest, type 1 T wave abnormalities were reproduced by intravenous adrenaline infusion (0.024 to 0.18 microgram/kg/min) but not by noradrenaline or by adrenaline after prior administration of oxprenolol. When the T waves had remained deeply inverted before infusion despite rest (type 2) adrenaline infusion normalised them and again noradrenaline was without effect. This effect was also prevented by oxprenolol. Type 3 changes were uninfluenced by catecholamine infusion. Plasma catecholamine estimations suggest that catecholamine hypersecretion and hypersensitivity may both be relevant, particularly the latter. The apparent bimodal response of the ventricular myocardium to adrenaline infusion is not surprising since in vitro experiments suggest that reversal of T wave polarity in either direction may result from summation of changes in action potential duration in different parts of the heart. Such changes may be unimodal, that is both areas involved show lengthening or shortening of action potential duration, but by occurring at different rates may lead to a bimodal change in the differences in duration which generate the T wave.

Adolescent↗
PubMed1979

A case of isolated primary chylopericardium.

Primary chylopericardium presented as radiographic cardiomegaly in an asymptomatic 19-year-old man. Normal findings at cardiac catheterisation and angiographic demonstration of cardiac displacement from the diaphragm suggested a collection of fluid below the heart which was confirmed by M and B mode ultrasound scanning. Thoracic blood pool isotope scanning indicated that the lumen was a pericardial effusion rather than a cyst. Lymphangiography did not indicate any direct lymphatic communication though a small pool of contrast appeared in the pericardium and the diagnosis of chylopericardium was confirmed by pericardiocentesis. Surgical treatment was undertaken after rapid reaccumulation of chyle and the patient remains well 6 months later.

Adult↗
PubMed1978

The effects of feedback and consequences on transitional cursive letter formation.

Twelve first-grade students were employed to analyze the effects of (1) Verbal and Visual Feedback, (2) Verbal and Visual Feedback plus immediate rewriting of trained letters with one or more incorrect letter strokes, and (3) Potential Reinforcement on cursive letter strokes. Students practised both a set of trained and a set of untrained letters during each session. Feedback and reinforcement was administered only for trained letter strokes. The percentage of correct trained letter strokes increased during all conditions. Performance on the untrained but practiced and trained letter strokes followed the same general trend in response pattern. No consistent pattern of generalization was demonstrated with untrained and unpracticed letter strokes.

Journal Article↗