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Biomedical subjects

G Dakin

Publications and source records attributed to G Dakin.

6 recordsLinked to original sources
PubMed2001

Laparoscopic aortorenal bypass using a PTFE graft: survival study in the porcine model.

PURPOSE: To verify the technical feasibility of laparoscopic aortorenal bypass in a porcine model and to evaluate renal pathologic findings after a short survival time. MATERIALS AND METHODS: Laparoscopic aorta-to-left-renal artery bypass using an interposition Gore-Tex graft was performed in five animals. Renal function was assessed 1 week postoperatively and euthanasia performed after 14 days for histologic examination. RESULTS: The median surgical time was 210 minutes (range 160-260 minutes). The median time needed to perform the aorta-to-graft anastomosis was 65 minutes (range 50-75 minutes), and the median time required to create the graft-to-renal artery anastomosis was 50 minutes (range 45-60 minutes). No conversion to open surgery was needed. Two intraoperative complications were observed: one large-bowel perforation, which was managed laparoscopically, and one obstruction of the aorta-to-graft anastomosis caused by clots, which was managed by removal of clots with a balloon catheter. No major postoperative complications were observed. The mean preoperative and postoperative serum creatinine concentrations were 0.8 +/- 1.2 and 0.7 +/- 1.6 mg/dL, respectively. At autopsy, all but one of the pigs were found to have a patent aortorenal bypass. In one pig, we found a partially clotted graft. Histologic examination demonstrated an unremarkable kidney in four cases and a kidney showing aspects of coagulative necrosis with viable cells in the animal with the partially clotted graft. CONCLUSIONS: Laparoscopic aortorenal bypass is feasible. The short-term effect of the bypass on kidney vascularization seems promising, as demonstrated by pathologic findings. Laparoscopic aortorenal bypass could extend the indications for renal revascularization surgery.

Anastomosis, Surgical↗
PubMed2001

A biodegradeable membrane from porcine intestinal submucosa to reinforce the gastrojejunostomy in laparoscopic Roux-en-Y gastric bypass: preliminary report.

BACKGROUND: A Silastic ring has been used to prevent dilation of the gastrojejunostomy in Roux-en-Y gastric bypass (RYGBP). The use of a bio-membrane may prevent dilation of the anastomosis without the risks associated with prostheses. The aim of this study was to evaluate the feasibility and safety of applying such a bio-membrane around the gastrojejunostomy in Laparoscopic RYGBP (LRYGBP). METHODS: We used a new bio-membrane, that is derived from porcine small intestinal submucosa (SIS) and acts as a scaffolding for the ingrowth of connective tissue. Over a 4-month period, 14 LRYGBP patients had their proximal anastomosis wrapped with 10 x 2.5 cm SIS by a single surgeon. We compared these patients to a control group of LRYGBP patients matched for BMI. RESULTS: The average age of the patients was 35.0 years (control group: 45.1 years). The patients had a mean initial BMI of 44.7 kg/m2 (+/- 5.9) standard error, and the control subjects had a mean initial BMI of 46.7 kg/m2 (+/- 6.5). SIS application took a mean time of 11 (+/- 3) minutes without any intraoperative complication. The median hospital stay was 3.5 days in the experimental group and 3.7 days in controls. Three patients developed a symptomatic stenosis at the gastrojejunostomy following surgery. In the control group there were two stenoses. At an average follow-up of 87 days (controls: 95 days), the mean reduction in BMI was 7.8 (+/- 0.8) kg/m2 [controls 8.6 kg/m2 (+/- 1.5)]. CONCLUSION: Application of SIS around the gastrojejunostomy in patients undergoing LRYGBP is feasible and safe. Further follow-up is required, however, to evaluate the effectiveness in preventing dilation of the anastomosis.

Adult↗
PubMed1998

Gene therapy in allergic encephalomyelitis using myelin basic protein-specific T cells engineered to express latent transforming growth factor-beta1.

A myelin basic protein (MBP)-specific BALB/c T helper 1 (Th1) clone was transduced with cDNA for murine latent transforming growth factor-beta1 (TGF-beta1) by coculture with fibroblasts producing a genetically engineered retrovirus. When SJL x BALB/c F1 mice, immunized 12-15 days earlier with proteolipid protein in complete Freund's adjuvant, were injected with 3 x 10(6) cells from MBP-activated untransduced cloned Th1 cells, the severity of experimental allergic encephalomyelitis (EAE) was slightly increased. In contrast, MBP-activated (but not resting) latent TGF-beta1-transduced T cells significantly delayed and ameliorated EAE development. This protective effect was negated by simultaneously injected anti-TGF-beta1. The transduced cells secreted 2-4 ng/ml of latent TGF-beta1 into their culture medium, whereas control cells secreted barely detectable amounts. mRNA profiles for tumor necrosis factor, lymphotoxin, and interferon-gamma were similar before and after transduction; interleukin-4 and -10 were absent. TGF-beta1-transduced and antigen-activated BALB/c Th1 clones, specific for hemocyanin or ovalbumin, did not ameliorate EAE. Spinal cords from mice, taken 12 days after receiving TGF-beta1-transduced, antigen-activated cells, contained detectable amounts of TGF-beta1 cDNA. We conclude that latent TGF-beta1-transduced, self-reactive T cell clones may be useful in the therapy of autoimmune diseases.

Animals↗