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Biomedical subjects

S Raju

Publications and source records attributed to S Raju.

At least 91 records · Page 5Linked to original sources

Twelve-hour and twenty four-hour preservation of small bowel allografts by simple hypothermia. Survival utilizing cyclosporine.

Canine small bowel was harvested and stored by simple hypothermic technique. After 12- and 24-hr storage, respectively, the small bowel graft was allotransplanted into recipients. All animals receiving 12-hr stored grafts (n = 9) survived beyond 5 days. In the 24-hr storage group, 67% of the animals (n = 9) survived beyond 5 days. Successful storage for such extended periods by simple hypothermia has not been achieved previously. Donor pretreatment with antibiotics as well as extensive intraluminal irrigation of the harvested small bowel are considered to be important technical features in this successful preservation.

Animals↗

Long-term survival of orthotopic bowel allografts in the rat treated with short-term low-dose cyclosporine.

Orthotopic bowel transplantation continues to be a "difficult" procedure, both experimentally and clinically, despite the advent of cyclosporine. Even with high-dosage CsA administration, long-term survival has been sporadic and short-term mortality high. In the present study, a low-dosage CsA regimen (5 mg/kg/day for 2 weeks postoperatively) produced prolonged survival in BN-Lewis donor/recipient combinations utilizing an orthotopic bowel transplantation model with portal venous anastomosis. The transplanted bowel continued to survive despite the lack of maintenance dosage after initial induction. The recipient animals evinced donor-specific hyporesponsiveness as donor skin grafts were rejected in a slow, indolent fashion. Third-party skin grafts acutely rejected in normal fashion. It was remarkable that the bowel grafts continued to survive in good condition despite the rejection of donor-specific and nonspecific challenging skin grafts placed on the animals. The precise mechanism of this donor-specific hyporesponsiveness is not known.

Animals↗

Orthotopic nonauxiliary total bowel transplantation using rats: technical procedure.

A procedure for nonauxiliary orthotopic total bowel transplantation is described, in which the graft from jejunum to distal colon is transplanted with portal venous drainage in end-to-end fashion in a one-stage procedure. The early postoperative mortality (within 4 days) was 23.8% in this study and presently is approximately 20% in our laboratory. It is noteworthy that the incidence of venous thrombosis is very low in this model. Continuous venous infusion, vascular perfusion, and luminal irrigation with Euro-Collins solution were employed in this preparation. The technique described is expected to prove useful for orthotopic nonauxiliary bowel transplant investigation because of its technical simplicity, low early postoperative mortality, and low incidence of vascular complications.

Animals↗

Tumors and tumor-like conditions of the middle ear and mastoid: role of CT and MRI. An analysis of 100 cases.

CT and MRI scanning provide valuable information in determining location and extension of middle ear and mastoid tumors and tumor-like conditions. The bone anatomy depicted by CT better delineates the involvement of the middle ear diseases. In glomus tumors, facial nerve tumors, and other cases including temporal bone metastases, the combination of CT and MR imaging is exceedingly useful in the diagnosis and management of patients.

Cranial Nerve Neoplasms↗

Otogenic intracranial inflammations: role of CT.

This article reviews the authors' results using CT in the diagnosis of 18 selected patients who were clinically suspected of having otogenic intracranial complications, demonstrating with illustrative examples the important role of CT in diagnosing various stages of acute coalescent mastoiditis and its associated complications.

Adolescent↗

Head and neck: high field magnetic resonance imaging versus computed tomography.

A comparative review of head and neck lesions examined with both CT and MRI showed that the location and extent of lesions can be more precisely evaluated with MRI. MRI allows better differentiation of neurogenic tumors from other lesions. Vascular structures are easily visualized on MRI without intravenous contrast and can easily be differentiated from lymph nodes. However, cystic lesions and necrotic nodes sometimes could not be differentiated from solid lesions when using MRI.

Branchioma↗

CAPD patients as renal transplant patients.

Most authors state that the continuous ambulatory peritoneal dialysis (CAPD) patient is not at increased risk when transplanted. These patients are always exposed to the risk of peritonitis, which may increase if patients are peritoneally dialyzed while immunosuppressed. The postoperative course of patients transplanted from our CAPD program from 1979 through August 1985 was evaluated. The transplant survival of patients dialyzed by CAPD, home hemodialysis, and at a free-standing dialysis facility were compared. Pretransplant dialysis modality did not influence long-term transplant success. Three of seven patients who required dialysis postoperatively developed peritonitis. The dialysis catheter was removed in two patients and one was treated by lavaging the peritoneal cavity with antibiotics. There was one instance of dialysate leaking through a drain in the transplant bed. This patient was converted to hemodialysis for subsequent dialysis. The dialysis catheters were removed at the time of discharge from hospital. Literature review confirmed this experience. Peritoneal dialysis post-transplant exposes the patient to a 10-33% risk of peritonitis and a 10% risk of a wound complication. Peritoneal dialysis patients are subject to risks unique to peritoneal dialysis. These complications do not translate into excessive morbidity or graft loss.

Adolescent↗

PTFE grafts for hemodialysis access. Techniques for insertion and management of complications.

In a series of 602 procedures, over 90% of primary forearm insertions of PTFE grafts between the radial artery and a cubital vein were possible. Thrombosis of the graft, which was invariably due to venous outflow obstruction, was the most common complication encountered. Revision of the venous anastomosis was not necessary in about one-third of the thrombosed grafts if a size 3 coronary dilator could be passed and the augmentation test was satisfactory. For revisions, creation of a new venous anastomosis using a jump graft was preferred over patch angioplasty or venous endarterectomy. Crossing the elbow for this purpose did not adversely affect graft patency. The incidence of aneurysm formation and infection was 16% and 35%, respectively. Infections involving the graft were managed by drainage, antibiotics, and bypass of the infected portion. Immediate bypass and delayed bypass were equally effective. About one-half of the infected grafts were salvaged by these techniques. The most common organism was Staphylococcus aureus. With a combination of the techniques outlined above, the service life of individual PTFE grafts can be extended. Two-year access patency in this series was 77%.

Aneurysm↗

Total orthotopic small bowel transplantation with cyclosporine.

The efficacy of immunosuppression including intravenous cyclosporine was assessed in a dog model of total orthotopic small bowel transplantation. Without immunosuppression, allografted animals died before the thirteenth postoperative day. Cyclosporine and prednisone therapy afforded a sixfold increase in survival of allografted animals. Bowel preparation, such as ex-vivo irradiation, treatment of the donor animal with antithymocyte globulin (ATG), or bowel preservation, did not appear to affect survival. However, a preliminary study of combination therapy using azathioprine, ATG, prednisone, and cyclosporine indicated that there were fewer early deaths as compared with other groups. Histologically, allografted bowel showed various degrees of mucosal change to which poorer nutritional aspects were attributed. "Intestinal death" caused by rejection was considered to be the principal cause of death in animals with advanced mucosal changes, in particular those who were long-term survivors. However, other debilitating factors (e.g., superimposed infection, endotoxemia, or possibly graft-versus-host reaction) may be present in nonsurvivors demonstrating fewer pathological changes in the graft.

Aged↗

Total orthotopic small bowel allotransplantation in the dog. Features of atypical rejection and graft-versus-host reaction.

The critical histologic review of our experience with small bowel allotransplantation in the dog is presented. While "classical" rejection with dense small cell infiltration and mucosal destruction does occur, more common is the "atypical" rejection reaction in which cellular infiltration is sparse. This "atypical" rejection was characterized by a significant decrease of mucosal epithelial structures with increased mitotic figures in crypt cells and frequent vascular changes, including segmental fibrinoid necrosis and thrombosis with or without overlying mucosal destruction. Substantial regenerating capacity of bowel mucosa tends to compensate for the destruction, complicating the histology. The host lymph nodes and spleen present a histologic picture highly suggestive of GVH reaction. The reduction in host lymphocytes in these organs from karyorrhexis with replacement by histiocytes and subsequently by plasma cells is described. It is emphasized that rejection and GVH are not mutually exclusive and occur simultaneously. The decrease of functional mucosal mass could well account for the nutritional malsequelae. Also, the weakening of immune structures on the host and the graft side may predispose to catastrophic enterogenous infections, perhaps explaining the large number of animals that die without overt signs of rejection following small bowel transplantation.

Animals↗

Late hemodynamic sequelae of deep venous thrombosis.

Twenty-nine limbs in 19 patients who had deep venous thrombosis documented by phlebography were studied by hemodynamic techniques 2 to 13 years later (mean, 7 years). Two limbs were found to be "normal." Nine limbs were hemodynamically obstructed; the remaining 18 limbs had developed reflux abnormality. All of the nine limbs with obstruction demonstrated symptoms of severe swelling or ulceration. In contrast, limbs with valve reflux were either asymptomatic or had only mild to moderately severe symptoms. Correspondingly, the reflux hemodynamic derangement was also mild, with reflux confined to a single level (commonly the popliteal valve). The implications of the differences in clinical presentation and hemodynamic profile between this group with post-thrombotic valve reflux and the typical patient with stasis caused by chronic venous insufficiency are explored. The natural history of stasis sequelae of deep venous thrombosis has apparently changed somewhat since the introduction of anticoagulation therapy.

Arm↗

Renal revascularization for preservation of renal mass and function.

We advocate renal revascularization for preservation of renal mass and function. That revascularization can improve glomerular filtration and reverse vasculogenic renal failure appears well established. Proper selection of patients appears to be the key for achieving improvement of renal function after renovascular reconstruction.

Diagnosis, Differential↗

New approaches to the diagnosis and treatment of venous obstruction.

Diagnosis of chronic venous obstruction has hitherto depended on phlebographic assessment alone. The pitfalls in this method are noted and two simple hemodynamic techniques for measurement of venous obstruction are described. The techniques are easily performed, have a high degree of sensitivity and specificity, and are particularly useful in assessing various therapeutic approaches to venous obstruction. Our experience with a variety of surgical procedures for venous obstruction is described. Two such new procedures, primary arteriovenous fistula and perforator bypass for peripheral venous obstruction, are described in detail.

Adult↗

Histochemical studies with a monoclonal antibody raised against a partially purified soluble estradiol receptor preparation from human myometrium.

A monoclonal antibody (D5) raised against affinity-purified cytosol estradiol receptor (REC) from human myometrium has been used to stain human tissues by means of an indirect immunoperoxidase method. Good staining was obtained with ethanol-, glutaraldehyde-, or Carnoy's-fixed material but not with formalin or Bouin's fixation. Cytoplasmic staining of human breast tumors exhibited a highly significant correlation (P less than 0.001) with REC assayed by conventional estradiol-binding assay provided that allowance was made for both staining intensity and cellularity of the tumor; no correlation existed with soluble progesterone receptor content. Both patient age and tumor differentiation influenced staining patterns in the same way as did REC content. Cultured REC-positive human breast tumor cell lines (MCF-7, ZR-75-1, and CA-2) showed positive staining as did cultured epithelium from human milk. Epithelia in normal breast and fibroadenoma exhibited variable staining that rarely reached the intensity seen in REC-positive tumor cells. The staining patterns of human normal endometrium, myometrium, fallopian tube, ectocervix, endocervix, and ovary and neoplastic endometrium and ovary are described. In every situation thus far examined only cytoplasmic staining has been observed.

Adult↗