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Biomedical subjects

J Rygaard

Publications and source records attributed to J Rygaard.

At least 91 records · Page 5Linked to original sources
PubMed1980

Studies on lymphoid cells of adenoid tissue in relation to clinical findings.

Adenoid tissue was obtained at operation in 27 children admitted for adenoidectomy and in 6 controls. The occurrence of cells with cytoplasmic immunoglobulin was studied by immunofluorescence of tissue sections, and localization, number of cells and class of immunoglobulin were determined. No differences were found between patients and controls. Mononuclear leucocytes isolated from adenoid tissue and from blood were compared. In the patients, the proportions of B lymphocytes were higher in the tissue than in the blood, in particular IgG-, IgM- and IgD-carrying cells. Stimulation in vitro with polyclonal activators induced less thymidine incorporation in adenoid cells than in blood cells. Stimulation with heat-killed Haemophilus influenzae induced a high response inadenoid cells from 7/20 patients with negative nasopharyngeal culture for H. influenzae, whereas all 7 patients who harboured H. influenzae in the nasopharynx were low responders.

Adenoidectomy↗
PubMed1980

Depressed suppressor cell activity in patients with newly diagnosed insulin-dependent diabetes mellitus.

Suppressor cell activity (SCA) was studied in twenty-eight patients with insulin-dependent diabetes mellitus (IDDM), both newly diagnosed and of longer standing. Suppressive effect of peripheral blood lymphocytes from the patients was tested after 48 hr of incubation with concanavalin A followed by inactivation. Suppression was measured as the ability of the lymphocytes to inhibit 3H-thymidine incorporation in concanavalin A-stimulated normal donor lymphocytes. SCA was expressed in relation to the activity of peripheral blood lymphocytes from simultaneously investigated healthy control individuals. The main findings were: (1) SCA was significantly depressed in newly diagnosed diabetics and (2) newly diagnosed patients displayed significantly lower SCA than did patients with duration of disease between 2 and 8 months and between 5 and 8 years, who had suppressor cell activities not significantly different from healthy individuals. Earlier studies have pointed to the significance of immune reactions in diabetogenesis. On this basis, and on the strength of our present findings, it is suggested that an impaired SCA, causing a decreased inhibition of aggressive lymphocytes, may be implicated in the pathogenesis of insulin-dependent diabetes mellitus.

Adult↗
PubMed1979

Effects of thymus grafts in nude mice transplated with human malignant tumors.

The effect of neonatal thymus grafts implanted in nude mice previously transplanted with three different human malignant tumors - an adenocarcinoma of the colon, a malignant melanoma and a Burkitt's lymphoma - were studied. In all immunologically reconstituted animals tumord were rejected. Tumor rejection stated 2-3 weeks after thymus implantation, and was completed after 30-6 weeks. Histological examination of lymphoid tissues showed a correlation between immunological reconstitution and tumor rejection. The rejection process showed a characteristic histologic picture with 3 phases - an early, an intermediate and a late phase - these were similar in the three tumor types examined. The possible mechanisms of reconstitution and tumor rejection are discussed.

Adenocarcinoma↗
PubMed1979

Lymphocytes of adenoid tissue.

Adenoid tissue was obtained at operation from 27 children admitted for adenoidectomy and from 6 controls. The occurrence of cells with cytoplasmic immunoglobulin was studied semiquantitatively by immunofluorescence microscopy of tissue sections, by which localization, number of cells and class of immunoglobulin were determined. No differences were found between patients and controls. Cells isolated from adenoid tissue were compared with mononuclear leukocytes obtained from the blood. More B lymphocytes were found in the tissue, in particular IgM-carrying cells. This was more pronounced in the patient group. Cells were stimulated in culture with polyclonal activators and microbial antigens. The response of adenoid lymphocytes to Haemophilus influenzae (HI) was high in 7/27 patients; all patients in whom throat culture was positive for HI were low responders.

Adenoidectomy↗
PubMed1978

Passive transfer of diabetes mellitus from man to mouse.

Lymphocytes extracted from peripheral-blood samples from each of six patients with newly diagnosed insulin-dependent diabetes mellitus were transplanted into arthymic nude mice. At one or more sampling times (in the thirty-day study) blood sugar was higher in mice which had received lymphocytes from diabetic patients than in the control mice which had received lymphocytes from non-diabetic donors. Blood-sugar concentrations reached 260 mg/dl in some mice in the experimental group. This study demonstrates that lymphocytes may have an aggressive role in diabetogenesis. With this mouse experimental model mechanisms involved in diabetogenesis, and probably also in other disease in which lymphocytes are suspected of being involved in pathogenesis, could be investigated.

Adolescent↗
PubMed1978

Is the diabetogenic effect of streptozotocin in part thymus-dependent?

Following a single injection of 200 mg streptozotocin/kg BW, 25 out of 25 normal mice became diabetic, whereas 12 ( = 20%) out of 50 athymic nude mice did not develop diabetes. In a multiple dosage experiment, where the same total dose was given over a 5 days period, 14 normal and 15 athymic nude mice all became diabetic, but nude mice had significantly lower blood glucose values. These results support our previous suggestion that a thymus dependent immune reaction is, in part, responsible for the diabetogenic effect of streptozotocin.

Animals↗
PubMed1978

T-lymphocytes transfer streptozotocin induced diabetes mellitus in mice.

Diabetes mellitus induced by low dose treatment with streptozotocin in BALB/c mice was passively transferred to syngeneic recipients with a predominantly T-lymphocyte fraction of spleen cells. This fraction was prepared by density centrifugation and passage through an antimouse immunoglobulin coated column. Variation in numbers of injected cells in the range of 10(3) to 10(7) showed that the smaller cell numbers gave the highest blood sugar values. Athymic nude recipients of BALB/c background also developed diabetes following similar transplants. A preliminary result was that the highest blood sugars were seen after transplantation of T-lymphocytes treated by low dose irradiation (200 R). This may reflect a specific effect on T-suppressor lymphocytes.

Animals↗
PubMed1977

Passive transfer of streptozotocin induced diabetes mellitus with spleen cells. Studies of synogeneic and allogeneic transfer to normal and athymic nude mice.

This study shows passive transfer of streptozotocin induced diabetes mellitus in mice. Transplants of spleen cells from BALB/c mice, streptozotocin treated for 5 days, induced diabetes in normal BALB/c recipients. Treatment of transplants with anti-theta and complement resulted in a significant decrease in the degree of diabetes. Athymic nude mouse recipients of BALB/c background also developed diabetes after transpant of spleen cells from both syngenic and allogenic (C-7/Bl/6) donors. It is concluded that passive transfer of chemically induced diabetes in mice is practicable, in both syngeneic and allogeneic combinations, and that thymus derived lymphocytes are significant in this process.

Animals↗
PubMed1976

Restitution of streptozotocin induced diabetes mellitus in nude mice with pancreatic grafts from the rat.

Transplants of 1-3 rat pancreases have proven to restitute streptozotocin induced diabetes in athymic nude mice. One out of 9 diabetic nude mice showed restitution following subcutaneous implantation of 1 rat pancreas. Three out of 6 nude mice were restituted by 2-3 grafts. Implants of rat submandibular gland did not restitute nude mice similarly treated with streptozotocin. The model seems of interest in studies of inter-species transplantation of pancreas.

Animals↗
PubMed1976

The inability of a diabetogenic virus to induce diabetes mellitus in athymic (nude) mice.

The effect of a known diabetogenic M-strain encephalomyocarditis (EMC)-virus in athymic nude mice (lacking the thymus-dependent lymphocyte system), and in heteroxygous littermates and homozygous normal mice of the background strain (C57/B16) was investigated. While by 3 weeks 4 out of 4 surviving virus-inoculated littermates and 9 out of 9 inoculated normal mice developed diabetes mellitus, none of the 7 surviving virus-inoculated nude mice became diabetic. Virus was isolated from all inoculated animals, including non-diabetic nude mice. It is concluded that it is the response of the thymus-dependent lymphocyte system evoked by the virus rather than the virus itself that leads to damage to the insulin producing cell.

Animals↗
PubMed1976

Immunological unresponsiveness of nude mice to LCM virus infection.

The acute LCM infection in nude mice runs a course which is clinically inapparent, and neither a humoral nor a cell-mediated immune response could be detected. Furthermore, during this infection the blood virus titers reached extremely high values. These observations are contrary to what is seen when ordinary normal mice are infected with the LCM virus but identical with the events following infection of ordinary but immune-deficient mice. Despite the absence of immune responses to the virus in the nude mice the very high virus titers obtained within the first few days of the infection declined somewhat during the following weeks. This and the other observations made are discussed briefly in the light of the current hypothesis concerning the immune status of the nude mice and the pathogenesis of the LCM virus infection in mice.

Animals↗
PubMed1976

Chorioangioma with hydramnios and intra-uterine fetal death.

Chorioangiomas are benign placental tumours derived from fetal vessels, that occur with a frequency of approximately 1%. Often they are associated with hydramnios and intra-uterine fetal death. Based on a case of multiple chorioangiomas with a fatal course for the baby, aspects of the pathogenesis of hydramnios are discussed. Future development in ultrasounc technology may facilitate antenatal diagnosis.

Adult↗