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S Une

Publications and source records attributed to S Une.

At least 37 records · Page 2Linked to original sources
PubMed1997

A two-step digestion process and LAP-I cold preservation solution for human islet isolation.

Pancreatic islet transplantation has a high potential for treating diabetes mellitus, but long-lasting insulin independence has not been achieved in type I diabetic patients. In order to obtain better results, improvement is needed in many areas. The first area is the islet isolation process. The requirements for an islet isolation method are: 1) to produce a maximum number of healthy islets without demanding a high quality of donor pancreas; 2) to be able to perform the procedure with fewer numbers of personnel who may be without extensive skills and expertise; and 3) to lower isolation costs. In order to achieve these objectives, we have made two important modifications to the isolation process. One is the development of a new preservation solution, LAP-I and the other is the use of a two-step process for pancreas digestion, involving a short warm collagenase digestion, followed by cold mechanical digestion without collagenase. We also use a clear plastic digestion chamber in order to visualize the process. The chamber cover is designed to facilitate frequent removal of digested tissue fragments. The overall procedure is simple and straightforward, requires less manpower and is cost effective. Our procedure is described in detail, and its advantages are discussed.

Adenosine↗
PubMed1995

Fetal pancreas transplantation in miniature swine. V. The functional and immunodulatory effects of ultraviolet light on fetal pig islets.

We have used the pig as a large animal model for studies of fetal pancreas transplantation. Fetal pig pancreas (FPP) has also been proposed as a potential source of endocrine cells for the treatment of diabetes mellitus. Among the approaches to prevent rejection, the irradiation of donor islets with ultraviolet B light has been used for its immunomodulating properties. Our goal was to study in vitro the effects of UV-B irradiation of FPP on the function and immunogenicity of the tissue. FPP were collagenase-digested and cultured for 1-29 days prior to UV-B irradiation. Static incubation tests were used to measure glucose-theophylline stimulated insulin release. Data obtained at 300 J/m2 revealed no impairment of insulin release (78% to 129% of controls, P = ns). At 500 J/m2, a significant reduction of glucose-theophylline stimulated insulin release was observed with 50-60-day-old FPP (35% to 66% of controls, P < 0.05), but not with 80-day-old FPP (93% of controls, P = ns). At both doses, prolonged observation in culture did not show any alteration of the growth and proliferation of islet cell clusters. UV-irradiated (300 J/m2) adult and fetal pig islet allografts released C-peptide and survived > 200 days. The immunogenicity of irradiated tissues was determined in vitro with allogeneic mixed islet-lymphocyte cultures (MILC). Proliferative responses of allogeneic lymphocytes to UV-irradiated FPP were very significantly decreased by 52-91% at both 300 and 500 J/m2 doses. This effect was observed from 1 to 10 days following UV irradiation and was not modulated by exposure of the tissues to gamma-interferon. We conclude that UVB-irradiation of FPP at a dose of 300 J/m2 does not alter its endocrine function and growth and is effective in reducing tissue immunogenicity. This treatment may be a useful approach for fetal islet transplantation in large animal models.

Animals↗
PubMed1995

Clinical islet transplantation experience of the University of California Islet Transplant Consortium.

BACKGROUND: The University of California Islet Transplant Consortium was formed to evaluate the feasibility of performing clinical islet transplantation at different transplant centers by using a single centralized islet isolation laboratory. METHODS: From July 1992 through February 1995 seven adult islet transplantations were performed, six allografts and one autograft. Once procured, human pancreata were brought to the UCLA-VA Islet Core Laboratory for islet isolation and purification, which were then transported to different centers for transplantation. Patients 1 through 3 received their transplants in Los Angeles, patient 4 received her islet transplant in Torrance, and patients 5 through 7 received their transplants in San Francisco. RESULTS: Although none of these patients achieved insulin independence, four of seven had functioning grafts longer than 6 months as indicated by circulating C-peptide level greater than 0.7 ng/ml. Furthermore, improved glucose control as shown by a decreased insulin requirement was seen in 57% (four of seven patients) of these patients. The ability to isolate islets at a single laboratory and transport them long distances to different centers was shown in patients 4 through 7. CONCLUSIONS: Islet transplantation can be performed with improvements in blood glucose control, and islets can be isolated at a centralized location and successfully transported to different centers for transplantation.

Adult↗
PubMed1995

Immunological responses after vaccination pre- and post-surgery in dogs.

The effects of several commercially available vaccinations pre- and post-surgery on immune responses by monitoring the blastogenic responses of lymphocytes and humoral antibody responses in dogs were examined. Twenty clinical patients presented for surgery were studied. Canine parvovirus (CPV) serum antibody titers increased by twofold or more in 17 of 20 dogs and many dogs had an increase by day 7. In 3 of 4 dogs moderate hemagglutination inhibition (HI) titers (128 to 256) at the time of vaccination increased by twofold or more. Canine distemper virus serum antibody titers in 4 of 8 dogs with HI titers (< or = 32) at the time of vaccination had increased by twofold or more. In the blastogenic responses of lymphocytes to Concanavalin A and phytohemagglutinin, most dogs responded with a slight decrease following vaccination, but no significant change was noted. No adverse reaction caused by vaccination was noted and comparatively good production of serum antibody titers (CPV especially) was seen. Vaccination pre- and post-surgery neither induce severe immunosuppression, nor potentiate the severity of concurrent disease, and did not cause inapparent infection to become clinically apparent.

Animals↗
PubMed1995

Immunological responses to polyvalent canine vaccines in dogs.

The immunological responses to commercially available polyvalent vaccines in dogs were examined. There was a tendency in decreased lymphocyte counts on day 7 in the puppy and adult dogs. There was a significant increase in the blastogenesis of lymphocytes on day 7 and 21 in puppies, whereas no significant changes were seen in the adult dogs. Delayed type hypersensitivity (DTH) responses to phytohemagglutinin (PHA) and canine parvo-virus (CPV) vaccine monitored 0, 3, 8 weeks after vaccination produced strong reactions, in particular those to CPV vaccine rose significantly after vaccination and maintained the higher responses for at least 2 months. Therefore, it is considered that vaccination is immunomodulative rather than immunosuppressive and that DTH responses to PHA and CPV vaccine are helpful to monitor non-specific and specific immune functions in vivo.

Aging↗
PubMed1995

Effect of directly ultraviolet-irradiated allografts of fetal pancreas in experimental diabetic dogs.

The proliferative responses of UV-irradiated islets from fetal pancreas decreased to 53.8 +/- 4.7% (mean +/- SEM) compared to that of UV-irradiated islets by allogeneic mixed islet-cell lymphocyte culture. In 5 pancreatectomized dogs, UV irradiated fetal dog pancreas was transplanted either into omentum pouches or the spleen without immunosuppressive agents. The diabetic status (daily insulin requirement for hyperglycemia, decrease in body weight, urine glucose) improved in dogs after allo-transplantation. The survival time after total pancreatectomy was significantly longer in allografted dogs than those treated only with daily insulin injections.

Animals↗
PubMed1995

Postnatal development of tail motoneurons and muscles in cat.

The postnatal development of motoneurons in two tail muscles, the extensor caudae medialis (ECM) and extensor caudae lateralis (ECL), and that of ECL muscle fibers were studied in cats 1 week to 2 months old. The location of ECL and ECM motoneurons in cats of different ages did not change postnatally. Somal size (average of maximal and minimal diameters) of ECL and ECM motoneurons gradually increased, and the size distribution of ECL was bimodal at 2 months. The activities of succinate dehydrogenase (SDH) and phosphofructokinase (PFK) were studied to determine oxidative and glycolytic activities in ECL growth. SDH activity rapidly decreased between 1 week and 2 weeks of age, while PFK activities increased gradually.

Animals↗