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Biomedical subjects

R Munda

Publications and source records attributed to R Munda.

At least 73 records · Page 4Linked to original sources
PubMed1985

Use of Nd:YAG laser in pancreatic resections with duodenal preservation in the dog.

The trend in recent years for treatment of pancreatic carcinoma and occasionally for pancreatitis has been towards total pancreatectomy. The pancreas is also now being harvested for transplantation. Any operative technique that can reduce operating time, blood loss, and associated morbidity and mortality would be of tremendous advantage. The aim of this study was to undertake a total pancreatectomy using the Nd:YAG laser (wavelength 1,060 nm) with a helium neon laser (wavelength 628 nm) incorporated to provide a marker beam. The laser beam was passed into a 400 micron flexible glass fiber enclosed in a 2.5 mm polyethylene cannula, which also served as a conduit for coaxial CO2. The laser was operated in a continuous wave mode, and the fiber exit beam had a divergence of 10 degrees. For photocoagulation and tissue vaporization, peak powers of 50 W were used with 0.5-1 sec pulses. The total pancreatectomy using the Nd:YAG laser was performed in eight dogs, and ten dogs undergoing the conventional operative procedure served as controls. The findings indicate that the Nd:YAG laser could be used effectively and safely. The operating time was considerably diminished (P less than 0.01); the number of ligatures used was smaller; blood loss, graft survival, and duodenal viability were similar. The Nd:YAG laser offers a new therapeutic modality in the performance of tedious and often difficult pancreatic surgery.

Animals↗
PubMed1985

Renal transplantation in Alport's syndrome.

Nineteen patients (3 women and 16 men) with Alport's Syndrome and endstage renal failure received 23 allograft kidneys at two medical centers between 1972 and 1983. Ten patients had pretransplant splenectomies, and four patients had pretransplant thoracic duct drainage. After a mean follow-up time of 49 months, analysis revealed total allograft survival was 65 per cent at 1 year, 50 per cent at 2 years, and 57 per cent at 5 years. Pretransplant splenectomy resulted in 60 per cent allograft survival at 24 months mean follow-up. Pretransplant thoracic duct drainage resulted in 100 per cent allograft survival at 15.6 months mean follow-up. The overall allograft survival was greatest for three and four antigen-matched kidneys and for living related donor kidneys. Data indicated that 50 per cent of all allografts in men were functional at 50.8 months mean follow-up. All allografts in women were functional at 48.3 months mean follow-up. Three of four patients who expired had pretransplant splenectomies. From this study, the authors conclude that renal transplantation is the preferred method of treatment for patients with Alport's Syndrome.

Adolescent↗
PubMed1984

Donor-specific blood transfusions with stored and fresh blood in a rat heart allograft model.

Donor-specific transfusions ( DSTs ) using stored and fresh blood were investigated in a rat heart allograft model. Lewis rats were recipients of preoperative DSTs and cardiac allografts from ACI donors. Blood was stored for 0, 1, 2, 3, 4, and 5 weeks prior to transfusion. Allograft survival and recipient sensitization were recorded. In all DST groups, allograft survival was superior to nontransfused controls (P less than 0.05). Stored blood was equal or better than fresh blood, and a 2-week storage was optimal (P less than 0.05). Storage of 2 weeks or greater resulted in decreased sensitization compared to storage for 1 week or less (P less than 0.05). This study supports the use of stored blood to enhance allograft survival and reduce recipient sensitization.

Animals↗
PubMed1984

The late adverse effect of splenectomy on patient survival following cadaveric renal transplantation.

Kidney and patient survival of 351 consecutive patients undergoing first cadaveric renal transplants since 1968 were reviewed to determine the effects of splenectomy on outcome. Special emphasis was given to analysis of 106 splenectomized and 102 nonsplenectomized patients treated since 1975. During the first two years after transplant, kidney survival was better in the splenectomized patients, with no adverse effect on patient survival. However, after the first two years, patient survival became significantly worse in splenectomized patients (35.5% vs. 60.5% at 84 months). Of the deaths, infection was the cause in 26.7% of nonsplenectomized patients compared with 50% of splenectomized patients (P less than 0.07). Of patients alive at one year posttransplant, death rates were not different in patients splenectomized before 1975 or after 1975. Timing of splenectomy (prior vs. concurrent) had no effect on outcome. The adverse effect of splenectomy on mortality appeared to be more pronounced in younger (less than or equal to 45 year-old) than in older (greater than 45 year-old) patients. Splenectomy should not be performed routinely in preparation for a cadaveric transplant because of an unacceptably high late mortality that is primarily from sepsis.

Adult↗
PubMed1984

The effect of donor-specific transfusions on rat heart allograft survival.

A rat heart allograft model employing donor-specific transfusions (DSTs) was used to investigate several questions relevant to their clinical usage. The effects of varying blood storage duration (stored vs. fresh), number and timing of DSTs as well as use of concomitant azathioprine and cyclosporine (CsA) were assessed in terms of allograft survival and recipient sensitization. A comparison of stored and fresh-blood DSTs revealed that blood stored for up to 5 weeks was as effective as fresh blood and that a 2-week storage was optimal. Increased storage appeared to be associated with decreased sensitization. Multiple DSTs were more effective than a single DST and the peak effect appeared after six. Transfusions given at the time of transplantation were ineffective. The addition of concomitant (preoperative) azathioprine or CsA resulted in a further decrease in sensitization but also resulted in a dose-dependent diminution of the transfusion effect.

Animals↗
PubMed1984

Appraisal of endocrine function of segmental autotransplanted pancreas in dogs.

There is increasing interest in pancreatic transplantation for patients with diabetes. In experimental models, endocrine function is usually monitored by determination of insulin and glucose levels in plasma. In this study following a segmental pancreatic autotransplant to the iliac fossa in dogs, a combined analysis of three pancreatic islet hormones, insulin, pancreatic polypeptide (PP) and glucagon was undertaken by radioimmunoassay of plasma. These were measured under basal conditions and following provocation with a standard meal, arginine, secretin and bombesin infusions. Immunohistochemical and electron microscopic examination of transplanted tissue was also performed. Circulating insulin and glucose levels in the surviving dogs with transplants reflected normoglycaemia with a normal tolerance to iv glucose and immunohistochemical detection of endocrine cells producing insulin, PP and glucagon. Secretory granules were found in A and B cells by electron microscopy. The normal circulating glucagon immunoreactivity could have originated in gastric antral A cells as well as in pancreatic tissue. It was not possible, however, to stimulate the autotransplanted pancreas to release detectable PP into the circulation.

Animals↗
PubMed1984

Proteinuria following transplantation. Correlation with histopathology and outcome.

A review of 693 renal transplant recipients revealed 77 (11%) in whom persistent, heavy proteinuria (greater than 2 g/24 hr) developed. Renal histology was available in all 77 patients. Twenty-one patients had received kidneys from living-related donors, the remaining 56 from cadaveric donors. The cause of proteinuria in these 77 patients was as follows: transplant glomerulopathy (30), allograft glomerulonephritis (22), chronic rejection (21), renal vein thrombosis (2), diabetic glomerulosclerosis (1), and hypertensive nephrosclerosis (1). Of the 22 patients who developed glomerulonephritis in the transplanted kidney, 6 had recurrent disease (3--membranous glomerulopathy, 2--focal sclerosis and hyalinosis, 1--membranoproliferative glomerulonephritis); 6 developed de novo glomerulonephritis; and in 10 the type of glomerulonephritis could not be classified as recurrent or as de novo because of lack of characterization of the original kidney disease. Renal vein thrombosis occurred in association with other lesions in an additional 5 cases (3--chronic rejection; 2--membranous glomerulopathy). In follow-up only 23.4% (18 of 77) of the patients maintained prolonged graft function; the majority of grafts being lost within one year of the development of persistent, heavy proteinuria. Of the 18 patients who retained their grafts, 8 had glomerulonephritis, 5 transplant glomerulopathy, and 5 chronic rejection. This study confirms the poor prognosis that has been reported with the development of nephrotic-range proteinuria in renal allograft recipients.

Graft Survival↗
PubMed1983

Polytetrafluoroethylene graft survival in hemodialysis.

Expanded polytetrafluoroethylene (PTFE) graft fistulas are widely used as secondary vascular access for patients receiving long-term hemodialysis treatment. Sixty-seven grafts were implanted in 48 patients and followed for 12 to 51 months. Cumulative patency for all grafts at 12 months was 67% +/- 6%, at 24 months 50% +/- 7%, and at 48 months 43% +/- 9%. Graft survival rates were different when considering graft configuration and location. Forearm straight graft survival at 12 months was 35% +/- 13%, upper arm curved grafts 60% +/- 19%, and forearm looped grafts 78% +/- 7%. Complications that decreased graft survival were related to thrombosis (21%), infection (25%), and intimal hyperplasia at the venous anastomosis (34%). After reviewing our experience, we believe that the challenge of secondary vascular access has not been solved by PTFE grafts. This should stimulate the search for better grafts and techniques.

Adult↗
PubMed1983

Studies on segmental pancreatic autotransplants in dogs.

Success with segmental pancreas transplants has been impaired by immunologic and technical considerations. Experiments were performed with autotransplants to avoid immunologic problems, allowing concentration on surgical techniques. Survival of splenic lobe pancreas autotransplants in pancreatectomized dogs was extended with relocation of the graft from the groin to the abdominal cavity and distal arteriovenous fistula to increase graft flow. Fibrosis of the graft occurred regardless of the method of duct treatment, latex (Neoprene) or Silastic injection or free intraperitoneal drainage. Hormonal responses in normoglycemic animals showed normal insulin levels (6 +/- 0.8 microU/mL) as compared with controls (5.4 +/- 0.9 microU/mL), while peak levels during arginine stimulation were higher in dogs with autotransplants (39.7 +/- 20 microU/mL) than in controls (15.1 +/- 1.9 microU/mL. Pancreatic polypeptide basal levels in animals with transplants were 42 +/- 2.2 pg/mL as compared with 256 +/- 28 pg/mL in controls, with no response to bombesin or protein meal stimulation. In this model, splenic lobe was capable of maintaining normoglycemia with avoidance of ketogenic amino acid patterns. Continuous fibrosis was the biggest threat to islet survival.

Amino Acids↗
PubMed1982

Transplantation of microbially contaminated cadaver kidneys.

Bacterial cultures of graft perfusion fluid were taken on 514 renal perfusions during a ten-year period. A total of 22 positive cultures were found. Two sets of kidneys were discarded because of the bacteriology report. Only two possible wound infections were found that could be attributable to the preoperative contamination even though 19 of 24 patients with "contaminated" kidneys received no antibiotics. No loss of kidneys or life was found. Of the 22 contaminated perfusates, 18 (80%) originated from other institutions although only 144 (28%) of the total kidneys that were perfused came from other institutions. The majority of cultures indicated that the organisms were skin contaminants or organisms of low virulence. Microbial contamination of perfused cadaver kidneys is uncommon (1.2% in local kidneys and 9.3% in shared kidneys). Contaminated kidneys are not a major source of infection in renal transplant recipients. Kidneys that are contaminated with frequently virulent Gram-negative bacteria, such as Escherichia coli, should be discarded. Contamination of kidneys with Gram-positive organisms should not be a contraindication for transplantation, but the patients should probably be given prophylactic antibiotics.

Cadaver↗
PubMed1981

Autotransplantation and ex vivo surgery for renovascular disease.

Renal transplantation and preservation techniques permit the use of vascular and microvascular surgical procedures for the reconstruction of renal vessels in situations where the size or location of involved renal vessels does not permit the application of standard in situ techniques. Six cases with renal vascular lesions were studied, one each of intimal fibromuscular hyperplasia, medial arterial fibroplasia, renal artery aneurysm, atherosclerosis, iatrogenic arteriovenous fistula, and traumatic venous laceration, that were repaired by ex vivo surgery and autotransplantation under cold storage or continuous hypothermic perfusion protection, which preserved renal tissue. We believe these techniques should be considered before nephrectomy is undertaken, especially in the patient with one kidney.

Adult↗