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Biomedical subjects

C W Putnam

Publications and source records attributed to C W Putnam.

At least 19 recordsLinked to original sources
PubMed1992

Effect of surgical manipulation of polytetrafluoroethylene grafts on microstructural properties and healing characteristics.

The effects on graft healing of alterations in the microstructure of polytetrafluoroethylene (PTFE) grafts induced by surgical instruments have not been fully elucidated. This study evaluates changes in the structural and physical properties of PTFE grafts resulting from the intentional application of commonly used surgical instruments and the influence of these changes on cellular ingrowth. The extent of cellular ingrowth into intact (10, 30, and 60 microns unreinforced and 30 microns reinforced [R]) and structurally compromised PTFE grafts (30 reinforced and 60 microns nonreinforced) implanted subcutaneously in Sprague-Dawley (n = 14) rats was evaluated at 7 and 21 days. The thrombogenicity of 10-, 30-, 60-, and 80-microns intact graft segments was determined gravimetrically after suspension in the internal jugular vein of dogs for 90 minutes. Cellular ingrowth consisting of fibroblasts, macrophages, and microvessels was directly related to porosity and was most extensive in 60-microns uncompromised graft segments, being 7-, 17-, and 20-fold greater than was observed in 60- and 30R-microns compromised grafts and undamaged 10-microns grafts, respectively. There was a direct relationship between porosity and thrombogenicity of intact graft segments suspended in the jugular vein. The amount of thrombus adherent to 80-microns graft segments was eightfold greater compared with 10-microns grafts. Manipulation of PTFE with surgical instruments significantly impairs healing and may be a possible etiologic factor in the poor long-term performance of these grafts.

Animals↗
PubMed1992

Peripheral vascular disease in heart transplant recipients.

The improved longevity of heart transplant recipients demands heightened awareness of the long-term complications of the procedure. Between 1979 and 1990, 232 patients received 241 heart transplants at our institution. Accelerated coronary atherosclerosis occurred in 45 (19%) of the 232 patients, typically appearing within 2 years of transplantation, whereas peripheral vascular disease (PVD) appeared in 23 (10%) of the 232 patients, usually within 3 years of transplantation. In the patients with PVD, 13 had occlusive disease, nine had aneurysms, and one patient suffered a vertebral artery dissection. Accelerated coronary atherosclerosis afflicted 12 (52%) of the 23 patients affected by PVD (p < 0.05) and preceded the development of PVD in all 12. Logistic regression analysis revealed risk factors predictive of the development of PVD after transplantation to be a pretransplant history of ischemic cardiomyopathy and posttransplant hypertension and hypertriglyceridemia (p < 0.05), with the presence of more than one risk factor increasing the probability of development of PVD. Those patients thus identified as at risk should be closely monitored for the development of PVD. Aggressive medical management of hypertension and hyperlipidemia in this subpopulation may forestall or prevent the development of peripheral vascular disease after heart transplantation.

Adult↗
PubMed1979

Liver allograft. Its use in chronic active hepatitis with macronodular cirrhosis, hepatitis B surface antigen.

A patient suffering from chronic active hepatitis with macronodular cirrhosis, positive for hepatitis B surface antigen (HBsAg), was treated with an orthotopic liver allograft. The HBs antigenemia, as measured with several precipitation tests and by complement fixation, became negative after transplantation and remained so for about 2 1/2 months. During the interval, very low titers of the antigen were detectable by radioimmunoassay. At about three months after transplantation, she had an attack of acute hepatitis, at which time HBsAg became detectable by all tests. She recovered, but progressive liver disease developed during the remaining 1 1/2 years of her life. She died of disseminated nocardiosis and candidiasis with deteriorating hepatic function. The homograft at autopsy showed no evidence of rejection, but was the site of chronic active liver disease, although of a different pathologic pattern than that affecting her native liver. The differences in histology may reflect the influence of chronic immunosuppression on the features of chronic active hepatitis.

Adult↗
PubMed1978

Acute neurological complications after liver transplantation with particular reference to intraoperative cerebral air embolus.

Nine of 48 adult patients who underwent orthotopic liver transplantation developed significant clinical neurological abnormalities recognized shortly after operation. Decrease in consciousness occurred with resultant coma, focal and generalized seizures and the occasional appearance of a state of akinetic mutism. Neuropathological abnormalities consisted of multifocal areas of infarction in cerebral cortex and basal ganglia in five patients, central pontine myelinolysis in five (often more extensive than usually reported), Wernicke's encephalopathy in three, glial nodules in two, and fungal abscesses in one. Alzheimer II astrocytosis was found in all brains available for retrospective study. There was direct evidence in two of the patients that air embolization from the homografts had occurred. Correlation of this with the brain infarcts in these and other cases seems reasonable. The ease with which air passed to the systemic circulation is explicable by the right to left venous--arterial shunts that are common in chronic liver disease. With the delination of this cause for the neurologic complications, measures to prevent it in future cases have been described.

Adolescent↗
PubMed1978

Pediatric cadaver kidneys for transplantation.

A group of 24 kidneys from donors ranging in age from 1 1/2 to 10 years were transplanted singly into adults and were compared to a group of 44 adult cadaveric kidneys transplanted into adults. There were no vascular complications in either group. There were two urological complications in the 24 pediatric donor cases and none with the adult donor cases. During the first month after transplantation, the mean creatinine clearance was lower in the pediatric donor group; later the function of the pediatric donor kidneys was at least as good as the function of the adult donor grafts. In the group of pediatric donor kidneys, the outcome using kidneys from donors younger than 3 years of age was less satisfactory than for donors 3 to 10 years of age. These data suggest that transplantation of a single pediatric kidney into an adult, particularly if the pediatric donor is at least 3 years of age, will provide satisfactory renal function.

Adult↗
PubMed1977

Portacaval shunt for glycogen storage disease and hyperlipidaemia.

Complete portacaval shunt was used to treat 10 patients with glycogen storage disease. A favourable effect was noted on body growth and a number of metabolic abnormalities. More recently, continous night feedings with an intermittently placed gastric tube or through a gastrostomy has been shown to be helpful either before or after portacaval shunts. Such alimentation techniques may eliminate the need for shunts in some patients and be of adjuvant benefit in others. Portacaval shunt was also used for three children who had homozygous Type II hyperlipidaemia. Substantial reductions in serum cholesterol concentration were observed, as well as resorption of xanthomas. Reversal of some cardiovascular lesions has been documented. The benefits of portacaval shunt in these disorders is probably due to the change in the hormone climate of the liver and the whole organism brought about by diversion of the hormone-rich splanchnic venous blood around the liver.

Adolescent↗
PubMed1977

A hundred years of the hepatotrophic controversy.

Venous blood returning from the splanchnic viscera has liver-supporting (hepatotrophic) qualities not found to the same degree in other kinds of arterial or venous blood. The effects of portal blood have been noted in animals with two livers (or a differential portal blood supply to different regions of one liver) to include hypertrophy, glycogen storage, hyperplasia, capacity for regeneration, increase of several synthetic functions, and maintenance of normal structure. The main splanchnic venous hepatotrophic factors are endogenous hormones of which the single most important is insulin. Thus, the foregoing portal hepatotrophic effects are largely eliminated with the diabetes produced by alloxan or total pancreatectomy. The injury of portacaval shunt is caused by the diversion of the hormones around the liver. Accordingly, the atrophy, injury to the organelles, and loss of the capacity for cell renewal is minimized if insulin is infused into the portally deprived liver. In these and other experiments, exogenous glucagon alone or the addition of glucagon to insulin has had no effect, but this may be because of the masking presence of gut glucagon and other hormonal or non-hormonal substances in our models. At present, the effects on the liver of exogenous insulin, glucagon, epidermal growth factor, and numerous other hormones are being determined by their intraportal infusion into eviscerated dogs in which other endogenous splanchnic factors have been eliminated.

Animals↗
PubMed1977

Fungus infections after liver transplantation.

The problem of fungus infections after liver transplantation was studied. In 100 consecutive recipients of orthotopic liver homografts there were 10 and 8 examples, respectively, of localized and disseminated infections caused by Candida species. Candidemia was demonstrated in 8 of these 18 patients. One patient who had a localized Candida infection also had disseminated cryptococcosis. An additional 31 patients were infested in that Candida could be cultured from sites where it is not normally found, such as the blood (8 examples), urine (8), ascitic fluid (8), and wounds (22). This exorbitant incidence of monilial infections and infestations was associated with a high frequency of complications involving the homograft as well as the hosts' gastrointestinal tract during the post-transplantation period. The yeasts found in blood, urine, ascitic fluid and elsewhere were thought to have originated from the gut. Ten of the 100 patients had aspergillosis which was localized in 7 instances and disseminated in 3. The lung was the most frequently affected organ. The fungus infections played a contributory role in the downhill course of our patients but in the event of death more fundamental and more frequent causes of failure were technical complications involving the homografts, difficulties in controlling rejection with reasonable immunosuppressive doses and bacterial sepsis. Suggestions have been made for the better control of fungal infections in liver recipients.

Ascitic Fluid↗
PubMed1977

Detection of porcine-specific canine antibodies by a radioimmunological technique.

A sensitive radioimmunological technique is described in which the primary interaction of 125I porcine membrane antigens with naturally occurring canine antibodies is measured by precipittion with 20% polyethylene glycol. Porcine membrane antigens were isolated, radiolabeled, and found to be maximally soluble in 20% polyethylene glycol solution. Binding of canine antisera to porcine antigens could be reduced by absorption with porcine lymphocytes. An eluate was obtained from a porcine kidney that was perfused in vivo for 330 min with oxygenated canine plasma and was identified as canine IgG by immunoelectrophoresis. When added to normal dog serum, the eluate markedly augmented the binding titer. Samples of dog serum taken after extracorporeal perfusion showed a significant decline in binding with no significant changes in lymphocytoxicity titer. These results suggest that this primary binding assay is a more sensitive indicator of the presence of graft-specific humoral antibodies and may be of value in evaluating prospective heterograft donors as well as in following the course of therapy.

Animals↗
PubMed1977

The radiology of ex vivo renal perfusion and autotransplantation.

The radiologic findings in 16 patients subjected to ex vivo renal perfusion and autotransplantation are reviewed. Preoperative excretion urography and renal arteriography are essential to define ureteral and arterial anatomy; renal scintiangiography and renography are useful for baseline studies. Plain radiographs should be obtained during nephrolithotomy. Intraoperative renal arteriography should be reserved for patients who require more precise definition of vascular anatomy or verification of adequate repair after a difficult dissection. Postoperative scintiangiography is required on the first day to exclude arterial occlusion. Renography and urography to evaluate autotransplant anatomy and function should be deferred for about 3 weeks, unless there is clinical evidence of a complication.

Angiography↗
PubMed1977

Biliary complications after liver transplantation: with special reference to the biliary cast syndrome and techniques of secondary duct repair.

In 93 consecutive cases of orthotopic liver transplantation, there were 24 example of biliary obstruction and eight of bile fistula formation. Six of the obstructed livers developed biliary cast formation so extensive that the smaller intrhepatic ducts became plugged to an extent that they could no longer have been treated by surgical mena. In each of the six cases, the most important causative factor was neglected obstruction of the large bile ducts with the intrahepatic lesions apparently being late and secondary. Stone and/or cast formation also occurred in other obstructed livers in the presence of bile fustulas, but these deposits were limited to the large ducts where they could have been or were removed. Although homograft bile undoubtedly has increased lithogenicity at certain posoperative times, the data from the present study have shown that biliary sludge formation essentially is always associated with defective bile duct reconstruction, and the observations have underscored the urgency with which reoperation must be considered. Techniques of secondary intervention have been described, with emphasis on conversion of cholecystojejunostomy to choledochojejunostomy. This operation has permitted salvage of homografts in eight of nine trials and the survival of seven patients.

Adolescent↗