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Biomedical subjects

S Shenoy

Publications and source records attributed to S Shenoy.

At least 73 records · Page 4Linked to original sources
PubMed1996

Changes in liver core temperature during preservation and rewarming in human and porcine liver allografts.

Liver core temperature during organ procurement, storage, and rewarming has not been reported in human orthotopic liver transplantations (OLT). We have shown in the rat that optimal temperature for liver storage is not 4 degrees C but 0 degree C to 1 degree C. Therefore, a study was undertaken in humans and in pigs to determine the pattern of temperature change during OLT. The porcine studies were performed, because it was not possible to follow human grafts during the period that they were sterilely packaged. Temperature depression in humans was rapid during organ perfusion, remained stable during organ dissection, and decreased again slightly, when after excision, the organ was perfused again. Temperature depression during the period of perfusion with University of Wisconsin (UW) solution was curvilinear with the initial rapid temperature depression followed by a period of slower temperature depression. Volume perfused versus time was linear during these periods and the relationship between temperature depression and volume infused was curvilinear. At the time of packaging, 65 +/- 12 minutes after start of cold perfusion, the liver core temperature was 5.7 degrees C +/- 1.3 degrees C. Studies in the pig showed that it took 75 to 100 minutes for liver core temperature to decrease below 5 degrees C, and core temperature reached a plateau at 1 degree C at 195 +/- 75 minutes after packaging. During the rewarming period in humans, while vascular anastomoses were being constructed, there was a rapid linear increase in temperature from 0.8 degree C, when the graft was removed from the cold, to 17.2 degrees C +/- 3.1 degrees C at 45.5 +/- 4.4 minutes later, just before portal reperfusion commenced. These studies show that it takes only a short time to cool livers down to 10 degrees C, but after flushing is stopped, temperature depression is markedly reduced, and ideal temperatures are not reached before packaging. Rewarming of livers during performance of vascular anastomoses is rapid and reaches temperatures at which substantial hepatic metabolism is occurring.

Animals↗
PubMed1996

Living-unrelated renal transplantation provides comparable results to living-related renal transplantation: a 12-year single-center experience.

BACKGROUND: The increasing success of renal transplantation is paralleled by the increased size of the waiting list. Efforts to increase the donor pool have included the use of living-unrelated kidney donors (LURDs). METHODS: During a 12-year period our center performed 309 transplantation from living donors; 279 patients received living-related donor (LRD) transplants, and 30 patients received LURD transplants. During the same period 543 patients received cadaveric renal donor transplants. A total of 86.7% of LURD transplants were spousal transplants. A total of 29% of the patients who received LRDs were human leukocyte antigen-identical with their donors and 53% were haploidentical, versus 0 human leukocyte antigen-identical or haploidentical in the LURD group. RESULTS: Twenty-seven (90%) Of 30 LURD recipients are alive, as are 240 (86%) of 279 LRD recipients. Mean current creatinine is 1.6 mg/dl for the LURD group and 1.7 mg/dl for the LRD group Kaplan-Meier 1- and 5-year graft survival was 94.9% and 82.9% for the LRD group, 93.1% and 85.9% for the LURD group (p = not significant), and 84.6% and 70.7% for the cadaveric renal donor group (p < 0.05). CONCLUSIONS: LURD patient and graft survival is comparable to LRD transplants despite inferior human leukocyte antigen matching. LURD transplant survival is superior to that of cadaveric renal donor transplants. LURDs are an excellent but underused source of organs for renal transplant recipients.

Adult↗
PubMed1996

Successful treatment of intraoperative malignant hyperthermia during renal transplantation.

Malignant hyperthermia is a complication of general anesthesia that is especially problematic if it occurs during renal transplantation because myoglobinemia, shock, and ischemia play a role in injuring the transplanted kidney. In this report, we describe a case of malignant hyperthermia, its clinical course, and the measures taken to successfully treat it and preserve the function of a kidney allograft.

Adult↗
PubMed1996

Comparison of survival of an expanded polytetrafluoroethylene graft designed for early cannulation to standard wall polytetrafluoroethylene grafts.

BACKGROUND: Placement and maintenance of a well-functioning vascular access are essential for delivery of adequate hemodialysis. Newly placed polytetrafluoroethylene (PTFE) arteriovenous grafts require a period of wound healing and incorporation of fibrous tissue before use, a period typically lasting two to three weeks. An ideal PTFE graft would be one that can be used for vascular access immediately, obviating the need for temporary dialysis catheters. Recently an expanded PTFE (ePTFE) graft with a mesh cannulation segment (Diastat graft) has been proposed for early cannulation. STUDY DESIGN: This is a retrospective single-center study comparing ePTFE graft survival to contemporaneously placed standard wall PTFE (GORE-TEX) grafts. RESULTS: Forty-seven consecutive new or established patients receiving chronic hemodialysis had grafts (25 ePTFE, 22 standard PTFE) placed between November 1994 and July 1995. There were no significant differences between the groups in age, race, gender, incidence of diabetes mellitus, or peripheral vascular disease. By the end of the study, 21 of 25 ePTFE grafts had clotted, compared with 11 of the 22 patients receiving a standard PTFE graft. Median time to first clotting was 53 days for the ePTFE grafts and 164 days for the standard PTFE grafts (p < 0.0001). Nine patients with ePTFE grafts required a temporary catheter after their first clotting episode. CONCLUSIONS: The ePTFE grafts thrombosed at a significantly higher rate than standard wall PTFE grafts. Further experience with the Diastat graft might improve graft survival. However, early experience does not suggest that the avoidance of short-term temporary access outweighs the problem of high clotting rate, and its attendant morbidity.

Arteriovenous Shunt, Surgical↗
PubMed1995

Serological evidence of past hepatitis B infection in liver donor and hepatitis B infection in liver allograft.

The presence of hepatitis B surface and core antibodies (anti-HBs and anti-HBc) in a liver donor without hepatitis B surface antigen is taken to indicate resolution of hepatitis B and is not considered to contraindicate donation. We report a liver transplant recipient who developed hepatitis B after such a donation. It seems that hepatitis B virus can reside in the liver of a patient who has seemingly recovered from his disease. We recommend avoidance of liver transplants from donors who are positive for anti-HBs and anti-HBc.

Female↗
PubMed1995

Transformation of mouse cells by wild-type mouse c-Src.

Previous studies in which chicken and human c-Src were overexpressed in chicken and rodent cells have indicated that overexpression of wild-type c-Src can not induce complete neoplastic transformation. However, studies with v-Src mutants have demonstrated that species-specific differences can play a significant role in transforming activity. Here we show that, in contrast to chicken c-Src, overexpressed mouse c-Src can induce significant anchorage-independent growth and tumorigenicity when transfected into NIH3T3 mouse cells. The biochemical cause for this difference is unknown. In particular, the protein-tyrosine kinase activities of chicken and mouse c-Src appear to be similar. This result is consistent with the hypothesis that v-Src-induced transformation results from perturbation of signalling pathways modulated by c-Src and highlights the need for caution in controlling for potential species-specific differences in studies of c-Src function.

Animals↗
PubMed1995

Cytolytic T lymphocytes from human renal allograft biopsies are tissue specific.

The cytolytic activity of T lymphocytes infiltrating renal allografts from recipients undergoing episodes of acute cellular rejection was studied. These T-cell populations, composed of both CD4+ and CD8+ cells, demonstrated significant cytolytic activity against both donor-derived KCLs and B-LCLs. In five of 21 biopsy-derived lines greater cytolytic activity was measured against donor KCLs compared to donor B-LCLs, suggesting the presence of kidney antigen-specific, MHC-restricted clones. Clones developed by stimulation with donor B-LCLs lysed both donor B-LCLs and KCLs while clones developed on donor KCLs as stimulator cells showed tissue specificity. Three of 26 clones recognized tissue-specific antigens in the context of donor MHC class I antigens lysing donor KCLs but not B-LCLs. These data demonstrate that a subpopulation of T cells recognizing kidney-specific antigens are present in biopsies of renal allograft recipients undergoing acute cellular rejection. This subpopulation of tissue-specific cytotoxic T lymphocytes may prove to contribute significantly to the pathology of allograft rejection.

Biopsy↗
PubMed1995

Anomalous ureteral insertion in VATER syndrome complicating renal transplantation.

We report a renal transplantation with uretero-ureterostomy to a normal ureter in a patient with VATER syndrome who had agenesis of the ipsilateral kidney. Anomalous insertion of the native ureter into the ejeculatory duct was subsequently identified when his post-operative course was complicated by an ureteric leak and hydronephrosis. To our knowledge, this anomaly has not been previously reported. Transplant function is now excellent following temporary percutaneous nephrostomy. Contrast delineation of genito-urinary anatomy is recommended, before utilizing existing anatomical structures in the urinary tract, in patients with VATER syndrome.

Abnormalities, Multiple↗
PubMed1995

Evidence of preservation injury to bile ducts by bile salts in the pig and its prevention by infusions of hydrophilic bile salts.

Preservation injury to bile ducts is a serious problem in liver transplantation, especially when preservation exceeds 12 hours. The authors hypothesized that the injury was caused by contact of bile ducts with bile salts during cold preservation and might be preventable by infusion of more hydrophilic bile salts. Swine livers were harvested after intraportal infusions of saline (control), of the hydrophobic bile salt taurodeoxycholate, or of the hydrophilic bile salts tauroursodeoxycholate or dehydrocholate. The effect of infusing a combination of hydrophilic and hydrophobic bile acids was also studied. Bile samples were taken before and during the infusions. Then livers were perfused with UW solution, ducts were flushed retrograde with UW, and livers were stored at 0 to 1 degree C for 20 hours. Bile ducts were harvested after preservation, and coded microscopic slides of the specimens were examined by light microscopy. There was large variability in baseline bile salt concentration. Injury after preservation consisted of sloughing and pyknosis of surface and glandular epithelium. The histologic injury score determined after preservation was directly related to bile salt concentration in bile ducts at the time of flushing. During bile salt infusions, the infused bile salt replaced most or all of the other bile salts present in bile. Severe postpreservation injury of intrahepatic ducts occurred after taurodeoxycholate infusions, but injury was minimal when either of the two hydrophilic bile salts was infused. The mixture of bile acids produced intermediate results. Retrograde flushing with UW does not prevent injury to intrahepatic ducts. The authors conclude that the injury is caused by contact with bile salts, is dependent on bile salt concentration and composition, and is preventable.

Adenosine↗
PubMed1995

Donor human leukocyte antigens in the circulation of liver allograft recipients.

Using a solid phase enzyme immunoassay (ELISA) with three different murine monoclonal antibodies (mAb) to HLA (human leukocyte antigens) framework determinants, circulating HLA were detected and quantitated both in normal individuals as well as liver allograft recipients. In normal individuals, the level of circulating HLA remained constant for several months of this study. The quantity of antigens present in the sera was not influenced by the collection procedures. During the immediate post-transplant period there was detectable donor HLA in the recipient's circulation; however, no correlation was noted between graft function and the large quantity of donor HLA present in the sera. Within 5 months after transplantation there was a gradual decrease in the amount of circulating HLA compared to the level seen in normal individuals. These shed donor antigens may play an active role in initiating the development of tolerance to the transplanted organ.

Blood Donors↗