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Biomedical subjects

B Garcia

Publications and source records attributed to B Garcia.

At least 73 records · Page 4Linked to original sources
PubMed1994

Host immune suppression after small bowel/liver transplantation in rats.

Simultaneous liver grafting in the Lewis (RT1)-to-DA (RT1) rat strain combination protects small intestinal grafts from rejection. The present study examined host immune responses after combined small bowel/liver transplantation (SBL) in this model. Orthotopic liver transplantation and heterotopic small intestinal transplantation were performed simultaneously and compared with isolated small bowel allografts (SBA) and isolated small bowel isografts (SBI). All rats were sacrificed on postoperative day (POD) 7 or 14 for immunological and histological studies. The mean time to rejection of the SBA was 6.6 +/- 0.3 days. In contrast, there was no clinical or histological evidence of intestinal rejection in SBL recipients during the 14 days of follow-up. The SBL recipients showed clinical and histological evidence of graft-versus-host disease (GVHD). Lymphocyte proliferation and IL-2 production in response to donor antigens were suppressed after SBL transplantation compared with the SBA or the SBI controls (P < 0.05). Cell-mediated cytotoxicity and lymphocytotoxic antibody production against donor cells were also significantly inhibited in the SBL recipients compared with the SBA control group (P < 0.05). We conclude that SBL transplantation in the Lewis-to DA rat strain combination: (1) suppresses host alloimmune responses, (2) prevents early intestinal rejection, and (3) favors the development of GVHD.

Animals↗
PubMed1994

Timing of surgery influences survival in receptor-negative as well as receptor-positive breast cancer.

Analysis of oestrogen and progesterone receptor (ER, PR) status was interpreted in relation to menstrual phase at the time of surgery and survival in 84 women diagnosed with breast cancer between 1975 and 1988. We showed previously (Br J Surgery 1994, 81, 217-220) that long-term survival was significantly poorer when surgery was performed during the follicular phase of the menstrual cycle compared to luteal phase; we now demonstrate that this effect on survival is at least as important in receptor-negative as receptor-positive patients. At 10 years, overall survival (OS) of ER-positive patients who had their biopsy during the follicular phase was significantly poorer than for those whose biopsy was performed during the luteal phase of their menstrual cycle (52 versus 88%, P = 0.02). OS for the ER-negative follicular phase group was also significantly poorer than that for the ER-negative luteal phase group (33 versus 76%, P = 0.009). The OS difference between the PR-positive follicular phase group and PR-positive luteal phase group was of borderline significance (60 versus 87%, P = 0.06), while the difference in OS between the PR-negative follicular phase group and that of the PR-negative luteal phase group was highly significant (13 versus 76%, P = 0.001). Disease-free survival for these groups followed a similar trend. The survival differences in receptor-negative women suggest that hormonal fluctuations at the time of surgery may have complex indirect effects on tumour growth and metastasis. The mechanism, if indeed independent of the tumour steroid receptors, could also apply in other cancers.

Adult↗
PubMed1994

Social-psychological dilemmas and coping of atomic veterans.

Memories and perceptions of exposure to radiation were explored in open-ended interviews with 16 atomic veterans. Findings suggest that resolution of these events involves emotional and cognitive processing of a new perspective that is in contradiction with prior beliefs.

Adaptation, Psychological↗
PubMed1994

Use of mammography in Jamaica. The Jamaica Cancer Society experience.

This is a study of the number of patients seen at the Jamaica Cancer Society during the year 1993. It was shown that less than one per cent of Jamaican women over the age of 20 years use this service. A lack of knowledge as well as difficulty in accessing the service, e.g. distance, appears to be the main contributing factor for this deficiency.

Adult↗
PubMed1993

Addisonian crisis as the presenting feature of bilateral primary adrenal lymphoma.

The authors report a patient with a primary lymphoma of the adrenal glands presenting as acute adrenal failure. Fine-needle aspiration biopsy of the adrenal glands revealed a non-Hodgkin lymphoma of predominantly small cleaved cells and a low degree of malignancy. The absence of abnormal findings in clinical, bone marrow, and computed tomography scan examinations supports the diagnosis of primary non-Hodgkin lymphoma of the adrenal glands. Chemotherapy produced a complete functional recovery, and tumoral masses disappeared after the first three cycles of treatment.

Addison Disease↗
PubMed1993

Gelatinolytic and caseinolytic proteinase activities in the secretions of the ventral, lateral, and dorsal lobes of the rat prostate.

The ventral, lateral, and dorsal lobes of the rat prostate produce secretions rich in protein. We examined these secretions for proteinase activities, using gelatin- and casein-containing SDS-polyacrylamide gel zymographies. The ventral lobe demonstrated both higher activities and more molecular forms of proteinase activities that cleaved these two protein substrates than did the other lobes. Ca(2+)-stimulated gelatinolytic activities of approximately 48, 51, 58, 64, 74, and 80 kDa were found in ventral prostate secretions in addition to activities detected in the absence of added Ca2+: a very strong 27-kDa activity; prominent 22-, 86-, 90-, and 94-kDa activities; and less active 36-, 41-, 100-, 130-, and 140-kDa activities. Ca(2+)-stimulated gelatinolytic activities of 51, 58, 74, 80, 86, 90, and 94 kDa were present in lateral prostate secretions (none were detected in secretions of the dorsal lobe), and Ca(2+)-independent activities of 25, 27, and 100 kDa were found in secretions of both the lateral and dorsal lobes. The Ca(2+)-stimulated activities were inhibited by EGTA and EDTA. Benzamidine inhibited all gelatinolytic activities except for the 22-, 25-, and 27-kDa Ca(2+)-independent forms when Ca2+ was not added to the reaction buffer. However, in the presence of 5 mM CaCl2, the Ca(2+)-stimulated forms of proteinase were unaffected by benzamidine, whereas the other activities sensitive to benzamidine were inhibited. Prominent Ca(2+)-independent caseinolytic activities of 20, 23, 31, 37, 83, 89, and 94 kDa were detected in ventral lobe secretions along with less active forms of about 39, 48, 53, 57, 60, 63, 80, 103, 110, 125, and 160 kDa. Caseinolytic activities of approximately 23, 31, 53, 89, 94, 103, 120, and 125 kDa were found in lateral prostate secretions, and 89, 94, and 103 kDa activities were found in secretions of the dorsal lobe. Quantitatively, most gelatinolytic and caseinolytic activities were present in the soluble portion of the secretion of each prostatic lobe. The ventral, lateral, and dorsal prostate lobes all secrete gelatinolytic and caseinolytic proteinase activities; however, quantitatively the ventral lobe is the most notable in this function since its secretions contain more molecular forms and greater activities of these proteinases.

Animals↗
PubMed1993

Tolerance by old livers of prolonged periods of preservation in the rat.

To determine the tolerance of old livers to prolonged preservation, livers from aged rats (corresponding to humans in the sixth to seventh decades of life) were transplanted after specific periods of cold preservation. Male BN/BiRij rats received orthotopic, arterialized liver grafts from either young (5 months) or old (25 to 28 month) donor rats after liver storage for 12 (n = 6), 24 (n = 6) or 30 (n = 10) hours in University of Wisconsin solution. Outcome was assessed by survival, liver enzymes after transplantation, and histology of the grafts. There were no significant differences in survival rates between recipients of old and young grafts. All rats survived after 12-hr and 24-hr preservation except one recipient of an old graft preserved for 24 hr. After 30-hr preservation recipients of old and young livers had identical survival rates (60%). There was a strong correlation between the highest postoperative AST and ALT and the duration of preservation in all groups (P < 0.0001), but only in the 24-hr preservation experiments was the ALT significantly higher in recipients of old grafts than in recipients of young livers (P = 0.025). Age of the donor did not significantly affect the peak AST, but there was a correlation between donor age and the highest postoperative ALT (P = 0.007). Although intracellular vacuolization was a prominent histological finding in more than half of the old livers at the end of preservation, it was not associated with an increase in mortality. It is concluded that under the ideal conditions provided in the experiments, old rat livers tolerate long preservation periods with satisfactory graft survival compared with young livers.

Age Factors↗
PubMed1993

The effect of donor-recipient strain combination on rejection and graft-versus-host disease after small bowel/liver transplantation in the rat.

The initial clinical experience with simultaneous small bowel/liver transplantation (SBL) suggests that liver grafting may protect the small bowel from rejection. A pilot study of SBL in DA (RT1a) rats with Lewis (RT1l) allografts in our laboratory provided experimental support for this concept. However, the clinical applicability of the data was questioned because the transplants were performed in a low-immune-responder rat strain combination. This study examined the outcome of SBL in several rat strain combinations. Isolated small bowel transplants (SB) and SBL were performed in three groups: DA-->PVG (low immune responder), BN-->LEW (intermediate immune responder) and ACI-->LEW (high immune responder). Lewis-->Lewis isografts were used as controls. All of the rats with SB rejected their allografts, whereas all of the rats with simultaneous liver grafts had minimal or no signs of intestinal rejection. The outcome of SBL was profoundly affected by the donor-recipient strain combination. The low immune responders developed severe graft-versus-host disease. The intermediate immune responders developed mild-to-moderate GVHD and moderate liver rejection. The high immune responders developed severe liver rejection. In this study, the outcome of small bowel transplantation depended upon the strain combination used and whether or not a simultaneous liver graft was transplanted. The immune interactions that occur after multi-visceral transplantation are complex and cannot be easily predicted.

Animals↗
PubMed1992

Nuclear DNA density of parathyroid lesions.

Nuclear DNA density analysis was carried out on six normal control human parathyroid glands and forty-six pathological lesions of human parathyroid tissue. The pathological glands had originally been classified as twenty hyperplasias, twenty-one adenomas, and five carcinomas in accordance with clinical-pathological information. Specimens had been obtained through the Surgical Pathology Department of the University Hospital, London, in the form of either imprints from the cut surface of a lesion, or as cell separation samples from a paraffin block. Nuclear DNA ploidy analysis of the normal glands showed, as expected, a diploid cell population. Sixty-one percent of nuclei of the carcinomas were above 2C, extending to 7C. There was a significant difference in nuclear DNA content between normal and benign tissue versus tissue classified as carcinoma. No significant difference in nuclear DNA ploidy could be established between the benign adenoma and hyperplasia tissue; however, marked significant DNA ploidy differences were found between tissue from the latter two and carcinoma. DNA ploidy from cell image analysis using Feulgen's reaction can be useful in establishing a differential diagnosis between carcinoma and benign lesions.

Adenocarcinoma↗
PubMed1992

Metalloproteinase activities expressed during development and maturation of the rat prostatic complex and seminal vesicles.

The objective of this study was to characterize proteinase activities expressed during development and maturation of the prostate gland and seminal vesicles of the rat by using gelatin-and casein-containing SDS polyacrylamide gel zymography. The prostatic complexes of 2- and 10-day-old animals and the individual lobes of the prostate (ventral, dorsolateral, and anterior [coagulating gland]) and the seminal vesicles of 15-day-old animals expressed prominent gelatinolytic activities of approximately 64, 71, and 76 kDa. These activities had properties of metalloproteinases; i.e., they were stimulated by Ca2+ and inhibited by EDTA and EGTA. They were greatly diminished by 52 days of age (immediately postpuberty) and were not detected in the dorsal lobe of the adult. Less active gelatinolytic proteinases with molecular masses of approximately 34 and 43 kDa were expressed in the developing prostatic complexes and individual lobes and seminal vesicles, but they were not detected in postpubertal animals. Weak gelatinolytic activities of 82, 85, and 89 kDa were found in the prostatic complexes; these activities were greatly diminished in all prostate lobes with sexual maturation but were expressed in the seminal vesicles at all ages. A large-molecular-mass Ca(2+)-independent proteinase of 130 kDa or greater was first detected in the dorsolateral prostate at 21 days of age. This activity was expressed in both the lateral and dorsal lobes of the adult but was greater in the lateral lobe. Proteinase activities of about 22 and 26 kDa that were not stimulated by Ca2+ were detected in the ventral prostate at 15 days of age by means of both gelatin and casein gels.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1992

Histological and immunopathological analysis of recovered encapsulated allogeneic islets from transplanted diabetic BB/W rats.

Allogeneic islets encapsulated in an alginate/poly-L-lysine membrane and transplanted into diabetic BB/W rats resulted in graft failure within 2 weeks of transplantation. Graft failure was associated with a dense pericapsular infiltrate (PCI) that resulted in necrosis of the encapsulated islets. The PCI could be inhibited by immunosuppressive agents, including cyclosporine and dexamethasone, and this resulted in a significant increase in graft survival. Immunopathological characterization of the PCI indicated that there was a predominance of macrophages. T helper cells also appeared to be present in this PCI. Empty capsules were also found to induce a similar PCI that was identical in composition to that found around encapsulated islets. Thus alginate/poly-L-lysine capsules do not appear to be biocompatible and may account for the variable results in islet graft survival found with these capsules.

Animals↗