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Biomedical subjects

K Reemtsma

Publications and source records attributed to K Reemtsma.

At least 181 records · Page 10Linked to original sources

Impaired cytotoxicity of lymphocytes from patients with cancer.

We have investigated the ability of peripheral blood lymphocytes from 57 cancer patients and from 54 normal controls to exert cytotoxic activity in vitro on allogeneic target cells by using a residual tritiated proline assay. Phytohemagglutin was added to the cultures for potentiating the reaction. The cytotoxic potential of lymphocytes from cancer patients was significantly lower than that of healthy controls. Increased survival of target cells was found in numerous reactions with patients' lymphocytes, probably reflecting a "feeder" effect. The source of plasma used for testing, i.e., autologous or pooled normal homologous plasma, did not affect the strength of cytotoxicity reactions displayed by lymphocytes from either normal or cancer patients. A lower reactivity was generally seen in patients with metastatic disease than in patients with no evidence of distant spread.

Cell Line↗

Hyperinsulinemia and hyperglucagonemia following pancreatic islet transplantation in diabetic rats.

Fasting blood glucose (FBG), serum immunoreactive insulin (IRI), plasma immunoreactive glucagon (IRG), body weight, and caloric intake were measured in long-term islet-isografted rats eight to 10 months following intraperitoneal islet transplantation in in age-matched, sham-operated, concurrently followed normal and diabetic controls. Islet recipients had normal body weights, but they were significantly polyphagic, hyperinsulinemic, and hyperglucagonemic when compared with normals. Fasting blood glucose levels were reduced by 10 per cent. Several factors may be related to the occurrence of these abnormalities in long-term islet-isografted rats, including (1) the mass of islets transplanted, (2) the age of donor tissue, (3) the heterotopic location of islet grafts, and (4) the lack of normal innervation of transplanted islet cells.

Age Factors↗

Pancreatic islet isografts, allografts, and xenografts: comparison of morphology and function.

Neonatal rat pancreatic islets were transplanted intraperitoneally into adult streptozotocin-diabetic rats and mice. Isologous pancreatic islet recipients (12 of 12) showed consistent and permanent reconstitution of normoglycemia and normal weight gain as well as readjustment to normal of intake of water, urine volume, and glucose excretion for greater than 10 months when compared to age-matched normal (ten) and diabetic (20) controls. Revascularized isologous islet grafts were found to be adherent to both visceral and parietal peritoneum. Pancreatic islet allografts (ten) and allografts and xenografts did not appear to differ markedly; both were characterized by dense round-cell infiltration within 5 days after transplantation.

Animals↗

The kidney in streptozotocin diabetic rats. Morphologic, ultrastructural, and function studies.

In order to study the nephropathy associated with experimental streptozotocin diabetes, serila morphologic, ultrastructural, immunohistologic, and functional studies were done in diabetic Lewis rats to study the course of the nephropathy. Early in the course of diabetes, these animals developed an increase in mesangial matrix, with electron-dense material, IgG, and C3 in the mesangium. These alterations were progressive. Mesangial bars, proximal tubular vacuolization, and myeloid bodies were also present. Progressive increase in protein excretion and increase in creatinine clearance were observed. Hyperglycemia was accompanied by weight loss, persistent glycosuris, hyperphosphaturia, and hypercalcuria. Urinary glomerular basement membrane-like protein and major urinary protein were decreased. Normal age-matched controls showed no abnormalities. Some of the changes observed in diabetic rats are present in human diabetes.

Animals↗

Impaired cell-mediated immunity in patients with cancer.

The ability of peripheral blood lymphocytes to respond in vitro to phytohemagglutinin (PHA) and to allogeneic cells in mixed leukocyte reaction (MLC) was studied in 85 patients with cancer and in 50 healthy controls. The effect produced by sera from cancer patients on in vitro lymphocyte blastogenesis was tested on autologous cells and on homologous cells from a constant panel of 10 normal volunteers. Patients with cancer showed a distinct deficiency of cellular immune responsiveness reflected in a stage-related impairment of PHA and MLC reactivity. This deficiency seems at least partially attributable to the presence of lymphocyte depressive factors in cancer sera, since such sera reduced the reactivity of both autologous and normal homologous lymphocytes to a level that was significantly lower than that found in the presence of pooled normal serum. The inhibitory activity of cancer sera was directly related to the extent of the neoplasia.

Humans↗

Comparison of lymphocyte reactivity in patients with cancer, systemic lupus erythematosus and renal allografts.

The PHA and MLC reactivity of lymphocytes from patients with cancer, SLE or renal allografts was comparatively tested in the presence of autologous and of normal homologous serum. Sera from patients with advanced cancer, active SLE or chronic allograft rejection strongly inhibited the MLC reactivity of autologous lymphocytes. It is suggested that serum inhibitory factors might be antibodies which are directed against modified antigenic determinants of the major histocompatibility complex, and are capable of blocking T lymphocyte receptors.

Humans↗

Cardiac heterotransplantation. Morphological and immunohistological studies.

A vascularized heterograft model using outbred strains of animals was developed by transplanting mouse hearts heterotopically into rats. With this species desparity rapid but not immediate graft rejection was observed, with a predictably narrow range of graft survival times. Morphological and immunohistological studies showed early deposition of fibrinogen and vascular and myocardial inflammation without prominent or consistent localization of either IgG or C3. Later more extensive changes were observed, and deposition of IgG and C3 were more prominent in the grafts. Pretreatment of the recipient with cyclophosphamide alone or cyclophosphamide plus antigen prolonged graft survival; however, no statistically significant difference was noted between these groups. Morphological and immunohistological alterations preceded clinical rejection, and tissue injury appeared to be mediated by humoral and cellular immune mechanisms and by the coagulation system. This model is potentially useful for the study of heterotransplantation.

Animals↗

Intraoperative unidirectional intra-aortic balloon pumping in the management of left ventricular power failure.

Unidirectional intra-aortic balloon pumping (IABP) was applied to 28 adult patients undergoing open-heart surgery over a 35 month period. The patients were divided into three groups according to the temporal sequence of initiating IABP. Group A consisted of 4 patients who were in a low output state or in cardiogenic shock prior to study. All patients survived cardiac catheterization and surgery, and 3 (75 per cent) were long-term survivors. Group B included 15 patients who could not be weaned from cardiopulmonary bypass with the usual supportive measures. Twelve patients (80 per cent) were weaned from bypass with IABP, and 11 (73 per cent) were discharged from the hospital. Group C was composed of 9 patients who manifested a low cardiac output syndrome within the first 24 hours following surgery. IABP was initiated in the recovery room. Six patients (67 per cent) were discharged. The total experience with these 28 patients therefore includes 24 patients (86 per cent) who were weaned from IABP, 20 (71 per cent) who were discharged, and 18 (64 per cent) who were long-term survivors. The present criteria for the use of IABP in the cardiac surgical patient are defined.

Adolescent↗

Pancreatic transplantation in diabetic rats: renal function, morphology, ultrastructure, and immunohistology.

Serial renal morphologic, ultrastructural immunohisotlogic and functional studies were done on diabetic Lewis rats to evaluate the course of nephropathy and to study the effects of early pancreatic isografts on renal disease associated with streptozotocin diabetes. Three groups of experimental animals and one group of agematched controls were used. Group 1 consisted of 12 animals which were made diabetic with streptozotocin and which did not receive transplants. Early in the course of diabetes, these animals developed an increase in mesangial matrix, electron-dense material in themesangium, with immunoglobulin G, C3, and occasionally fibrinogen deposits in the glomerular mesangium. Alterations were progressive and mesangial bars, proximal tubular degeneration, tubular vacuolization, and myeloid figureswere present later. Progressive increase in protein excretion and increase in glomerular filtration rate were observed. Persistent glycosuria, hyperphosphaturia, andhypercalcuria. In contrast, only an occasional animal from Groups 2 and 3 with a pancreatic transplant showed renal in age-matched controls. These studies have demonstrated the evolution of renal glomerular and tubular changes in streptozotocin diabetic rats, and they have showed functional, and immunohistochemical changes.

Animals↗

Xenotransplantation of piscine islets into hyperglycemic rats.

Xenotransplantation of piscine islets into hyperglycemic rats usually lowers the blood sugar level of the recipient. The duration of this effect is prolonged by irradiation of the host or by enclosing donor tissue in synthetic envelopes. This prolongation appears to be related to interference with the host's ability to reject the graft; the duration of the prolongation may be limited by the host tissue reaction surrounding the envelope. The availability of anatomically separate piscine islet tissue makes it potentially useful for xenotransplantation into mammals.

Animals↗