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Biomedical subjects

T E Mandel

Publications and source records attributed to T E Mandel.

At least 163 records · Page 9Linked to original sources
PubMed1982

Detrimental effect of high medium glucose concentration on subsequent endocrine function of transplanted organ-cultured foetal mouse pancreas.

Single 17-day foetal mouse pancreases, cultured for 15 days in RPMI 1640 or DME containing either 1 or 4 g/l glucose, were grafted under the kidney capsule of syngeneic mice made diabetic with Streptozotocin. Islets cultured in media containing 1 g/l glucose secreted less insulin in vitro than those grown in media containing 4 g/l glucose. After transplantation, the blood glucose levels of diabetic mice grafted with islets grown in media containing 1 g/l glucose decreased to normal limits, whereas mice grafted with islets grown in media with 4 g/l glucose never became normoglycaemic. Histologically, grafts of tissue from high glucose cultures were smaller and had less well organized islet tissue than grafts from tissue maintained in physiological glucose concentrations. Islets cultured in DME secreted more insulin in vitro than those cultured in RPMI 1640, but the type of culture medium had no significant effect on subsequent graft function. These data support the concept that chronic exposure of foetal islets to high glucose concentration may be deleterious to their subsequent function as grafts despite the fact that they secrete more insulin in vitro.

Animals↗
PubMed1982

HLA-DR typing of fetal human spleen and liver lymphoblastoid cells transformed by Epstein-Barr virus.

Because few HLA-DR-positive cells are present in the fetal spleen and liver, full HLA typing cannot be performed. However, B lymphocyte precursors can be transformed with Epstein-Barr virus to produce lymphoblastoid cells which express HLA-A, B, and DR antigens. Successful transformation was achieved, usually with spleen and liver, in nine fetuses aged from 15 to 18 weeks, mostly within 7 to 14 days of initiation of the cultures. Spleen-derived lymphoblasts were more suitable for typing because of their greater homogeneity and higher viability. Tissues from two 13-week fetuses from prostaglandin-induced abortions and from a spontaneously aborted 22-week fetus could not be transformed. This is probably attributable to prolonged ischemia before the tissues were obtained but, in the 13-week fetuses, absence of B lymphocyte precursors was not excluded. HLA-DR typing may be useful in obtaining well matched donor-recipient pairs in fetal pancreatic islet transplantation.

Cell Line↗
PubMed1982

Organ culture of fetal mouse and fetal human pancreatic islets for allografting.

In organ culture of fetal human and fetal murine pancreas under "conventional" conditions (10% CO2 in air), the islet cells of both species survive, proliferate and function but the acinar tissue rapidly degenerates. Fetal mouse islet cells also survive in 90% O2 and 10% CO2 but nonendocrine cells, including fibroblasts and macrophages, degenerate. Fetal mouse islets grown in 90% O2 show diminished immunogenicity when transplanted into recipients differing across the entire MHC, but a reduced allograft response by the host is frequently still present in the absence of immunosuppression. Fetal human islets, grown in 10% CO2 in air, produce insulin in vitro for prolonged periods, and as xenografts, differentiate under the kidney capsule of athymic mice, suggesting that under appropriate conditions both in vitro and in vivo, the fetal human islets can survive. However, fetal human pancreatic cells of all types are highly susceptible to high oxygen concentrations and are rapidly killed. Because of the susceptibility of fetal human pancreas to oxygen, conditions for the culture of fetal human islets for allotransplantation may need to be modified from those tolerated by fetal mouse islets. Fetal human islets may be a useful source of transplant material in human insulin-dependent diabetes, but it is likely that tissue matching and immunosuppression may be required in addition to modification of islet immunogenicity by prior organ culture.

Animals↗
PubMed1982

Isotransplantation of fetal mouse pancreas in experimental diabetes. Effect of gestational age and organ culture.

Fetal mouse pancreatic isotransplantation was performed in CBA mice, previously made diabetic with streptozotocin. Either 17- or 12-day-old fetal tissue was used, either uncultured or after 14 days in organ culture. Grafts were placed under the renal capsule, and their effect on fasting blood glucose levels was assessed over a 10-week postgraft period. The grafts and the host pancreas were then examined by light microscopy. Uncultured 12- and 17-day fetal pancreases produced poorly developed grafts with small islets, numerous ducts, and copious adipose tissue. By contrast, if organ cultured for 14 days before transplantation, both 12- and 17-day tissue resulted in large grafts composed predominantly of well-stained islet cells, few ducts, and little connective and adipose tissue. The most functionally effective grafts were derived from cultured 17-day pancreas, and a single graft per recipient always ameliorated diabetes. By contrast, grafts from single or multiple uncultured 12-day pancreases did not function, but, after culture, grafts derived from three (but not from one) 12-day pancreas lowered blood glucose levels to almost normal levels. It is concluded that grafts of fetal mouse pancreas can function in experimental diabetes provided they are first cultured and are of adequate gestational age.

Animals↗
PubMed1981

Alkaline phosphatase in hematopoietic tumor cell lines of the mouse: high activity in cells of the B lymphoid lineage.

Alkaline phosphatase (EC 3.1.3.1) was assayed in a large number of cultured mouse tumor cell line using p-nitrophenylphosphate as the substrate. Of 19 lines of the B lymphoid lineage, including Abelson pre-B, B lymphoma, and plasma cell tumor lines, all but 1 had substantial activity averaging 407 nmol/min/mg protein (with a range from 5 to 900). Nine T lymphoid and 9 nonlymphoid hematopoietic lines examined had low activity of 0.7 to 4.2 nmol/min/mg protein. The enzyme was markedly enriched in plasma membrane preparations from the B lymphoid cells, but not in those from most T lymphoma cells. The activity of another plasma-membrane-bound enzyme, gamma-glutamyl transferase, did not vary systematically with the type of cell line but was exceptionally high in 1 T lymphoma line. Investigation of pH dependence and susceptibility to inhibition by L-phenylalanine and L-homoarginine indicated similarity of the alkaline phosphatase from B cell lines to the enzyme recoverable from normal mouse kidney, placenta, bone marrow, and lymphoid organs. The enzyme seems to provide a useful marker for tumor lines of the B lymphoid lineage and for their plasma membranes.

Alkaline Phosphatase↗
PubMed1981

Colonies formed in agar from human breast cancer and their identification as T-lymphocytes.

Single cell suspensions prepared from human breast cancer specimens by collagenase digestion were cultured in soft agar with phytohemagglutinin-stimulated human lymphocyte-conditioned medium (PHA-LCM). In 6 of 10 different tumors, PHA-LCM-dependent clonal growth was develop. After 12-14 days of incubation, two morphologic types of colony containing 20-500 cells were recognized. Both were composed of lymphocytes of T-cell nature, as judged by cell morphology in smears, cytochemical properties, capacity to form rosettes with sheep erythrocytes, and electron microscopic appearances. Contamination of the tumor cell suspensions by blood could be excluded as a source of the colony-forming lymphocytes, and the incidence of colony-forming cells correlated well with the degree of lymphocyte infiltration of the tumors. Some of the colonies in agar were expanded further in liquid culture in the continuous presence of PHA-LCM. These clones were apparently high in proliferating capacity as compared with the proliferating activity of peripheral T-cell clones obtained from normal blood. These clones were considered to be highly activated T-lymphocytes and to be stimulated to grow in vitro by the T-cell growth factor contained in PHA-LCM. The direct cloning and expansion of such activated T-lymphocytes infiltrating the tumors will be useful for studies on the functional characteristics of these cells.

Agar↗
PubMed1981

Long-term isografts of cultured fetal mouse pancreatic islets. The oncogenic effects of streptozotocin and the prevention of diabetic renal complications.

Female CBA mice made diabetic with a single intravenous dose of streptozotocin (STZ) were either grafted with cultured fetal mouse pancreatic islets onto the splenic capsule, treated with insulin, or left untreated. An age- and sex-matched group of nondiabetic mice served as normal controls. All islets-grafted and most insulin-treated mice survived and had normal fasting blood glucose levels. By contrast, of the untreated diabetic mice, one died and the survivors showed poor weight gain. Light-microscopic examination of the islet isografts showed a progressive increase in graft size and beta-cell granulation over the 9-month study period. Quantitative electron-microscopic examination of the kidney showed that, whereas the islet-grafted and nondiabetic control mice had similar glomerular capillary basement membrane (GCBM) thickness, the untreated diabetic and insulin-treated mice had markedly thickened GCBM. All STZ-treated mice develop diffuse hepatic dysplasia and, at later time points, some showed biliary hyperplasia, intrahepatic cysts, and occasionally nodular dysplasia. With increasing time after STZ, most mice developed renal adenomas. One untreated diabetic mouse also developed a solitary functional pancreatic beta-cell adenoma. STZ effects were not affected by treatment of diabetes.

Animals↗
PubMed1981

Long-term antigen retention by dendritic cells in the popliteal lymph node of immunized mice.

Antigen retention by follicular dendritic cells (FDC) was studied in the popliteal lymph nodes (PLN) of mice actively or passively immunized against human serum albumin (HSA) or horse spleen ferritin. Electron microscopic autoradiography was used to locate a challenge dose (1 microgram) of 125I-labelled HSA in the draining PLN following injection into the hind footpad of specifically immune mice. In both actively and passively immunized mice, the radiolabelled antigen was localized to the follicles in the cortex of the draining node. In actively immunized mice, the antigen formed a crescent of label on the superficial aspect of germinal centres, while in passively immunized mice label was seen in primary follicles. In electron microscope autoradiographs, the silver grains were concentrated in areas of dendritic cell processes which emanated from a cell body containing a characteristic irregular nucleus. The size and complexity of the dendritic cell processes increased in actively immunized mice suggesting that the FDC could hypertrophy. High resolution studies using the electron-dense antigen, ferritin, showed that it was localized to the extracellular space of the FDC processes and was associated with amorphous electron-dense material; presumably immune complexes. Antigen was not present uniformly distributed in the extracellular material but rather it was in discrete patches occupying small segments of the FDC processes. Large amounts of label-free electron-dense material were present suggesting that immune complexes of various specificities were present on each DC. Ferritin was seen more than 3 months after challenge but only on the FDC. The data suggest that the antigen retaining mechanism in the lymph node of immune mice is antigen non-specific, is capable of hypertrophy in response to active immunization and provides a mechanism for stable long-term retention of antigen.

Animals↗
PubMed1981

Thymus in mice bearing the Steel mutation. Morphologic studies on fetal, neonatal, organ-cultured, and grafted fetal thymus.

Mice with the Steel mutation were studied to determine whether they showed a morphologic difference in the epithelial-reticular microenvironment of the thymus when compared with their normal and heterozygous littermate controls. Thymuses taken directly from fetal and newborn homozygous SlWehi/SlWehi mice, after culture, and after subcapsular renal grafting were compared by light and electron microscopy with similarly treated thymuses from heterozygous SlWehi/+ and normal homozygous (+/+) littermates. At all developmental stages studied, the homozygous mutants had smaller thymuses with fewer lymphoid cells than their homozygous normal and heterozygous littermates. The homozygous mutants also showed ultrastructural abnormalities in the thymic epithelial cells. After organ culture, homozygous fetal mutant thymuses produced fewer lymphocytes and showed abnormalities of epithelial cell ultrastructure when compared with littermate controls. When mutant and control fetal thymuses were grafted under opposite kidney capsules of normal syngenic recipients, the mutant thymuses developed poorly and showed decreased lymphopoiesis and abnormalities of epithelial cell structure. The data suggest that there is a primary epithelial microenvironmental defect in the thymus of mice with the Steel mutation.

Aging↗
PubMed1980

Ontogenic development of B-lymphocyte function and tolerance susceptibility in vivo and in an in vitro organ culture system.

The maturation of B-lymphocyte function during fetal development was studied in vivo and in an in vitro organ culture system. The results indicated that the progenitors for 2,4-dinitrophenol (DNP)-specific B cells are present as early as 14 d of gestation in liver and possibly as early as 15 d in spleen. In addition, it was found that the organ culture system supports the development of B lymphocytes as measured by an increase in both the percentage of surface immunoglobulin-positive cells and the frequency of clonable DNP-specific B cells after culturing. The majority of anti-DNP-secreting clones resulting from the antigenic stimulation of fetal B cells produced only the IgM isotype, and the ability to secrete the IgG isotypes increased as a function of gestational age. Because fetal DNP precursors from spleens and livers that had been incubated in organ culture resulted in a greater proportion of clones secreting IgG compared with age-matched uncultured controls, it was concluded that the maturation with regard to the ability to secrete IgG can occur in vitro. In studies relating to the ontogenetic development of tolerance susceptibility, it was found that up to one-half of the DNP-specific B-cell precursors from livers and spleens less than 18 or 19 d of gestation were resistant to tolerogen treatment for 24 h as if in a pretolerant phase. However, if tolerogen were present for 3--5 d during organ culture there was near total elimination of potential DNP clones. This finding suggested that the 24-h induction period was insufficient for affecting the DNP-specific precursors in livers and spleens from the earlier gestational ages, and that a proportion of precursors could subsequently form DNP clones in the splenic focus assay after the removal of tolerogen.

Animals↗