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Biomedical subjects

O Jonasson

Publications and source records attributed to O Jonasson.

At least 91 records · Page 5Linked to original sources
PubMed1978

Search for latent cytomegalovirus in renal allografts.

Cytomegalovirus (CMV) infection is common after renal transplantation, and cytomegaloviruria occurs in about two-thirds of the recipients. These observations suggest that the allografts may be a site of latent infection with CMV and its reactivation may be the source of viruria. To investigate this possibility, 130 kidney specimens from 85 persons were cultured, and simultaneous explants were made of 63 of them from 50 people. No CMV was received from 33 normal kidney or cadaver donors or from 19 allograft recipients who had no evidence of posttransplantation infection with CMV. The experiment included 37 primary organ explants that yielded no evidence of latent virus. Among 33 allograft recipients with posttransplantation CMV infection, overt infectious virus was isolated from 6 of 57 allograft biopsies. All six positive specimens were from four patients, all of whom had viruria simultaneously. Organ explants from 20 of the recipients with demonstrated postoperative CMV infection, including 13 viruric patients, failed to unmask any latent CMV. Thus, allograft kidneys were infrequently infected with CMV (6%), even in patients with viruria (24%). The kidney parenchyma appears to be an uncommon site of latent CMV infection and may not be the usual source of virus in patients with viruria.

Cytomegalovirus↗
PubMed1978

Replacement of pancreatic beta cells as treatment for diabetes mellitus: a review.

At the present time, two major factors limit further clinical application of islet cell transplantation in treatment of the insulin-deficient diabetic patient. First, the yield of islet tissue obtainable from a single donor pancreas is insufficient for adequate reconstitution of normal beta cell mass. The purification procedures required to eliminate acinar contamination and allow safe portal vein infusion cause large islet cell losses. Other procedures designed to minimize islet loss result in crude preparations containing substantial acinar tissue. In dogs and rats, crude preparations have been inoculated with safety into the spleen and function well in this location, but such a procedure might not be feasible in the human. Preliminary trials of these techniques in the monkey have not been successful. Second, dispersed and isolated islets inoculated into any site are exceptionally vulnerable to rejection and cease to function within a few days. Successful human islet allografting must await development of improved techniques of histocompatibility matching and/or immunosuppression. An additional question, unanswered in experiments to date, relates to the probable requirement for accuracy in replacement of alpha cells and beta cells for cure of the insulin-deficient juvenile diabetic patient. In rats, transplantation of large volumes of islet cells has resulted in hyperglucagonemia, hyperinsulinemia, and polyphagia, although the rats remain normoglycemic and have normal glucose tolerance tests. Bewick has elicited hyperinsulinemia in dogs by denervation and shunting the pancreatic venous drainage from portal to systemic. The metabolic effects of this abnormal state have not been adequately studied. These unresolved issues mandate that pancreatic transplantation remain an experimental procedure in humans. Whole or segmental pancreatic implants are technically feasible and are capable of function for extended periods of time. Islet implantation is reserved for carefully controlled experiments and in patients immunosuppressed for other organ transplants.

Aging↗
PubMed1977

Percutaneous biopsy of renal transplants using ultrasonographic guidance.

The transplanted kidney is an ideal organ for study by ultrasonic methods because it is located superficially in the iliac fossa and it is free of superimposed echoes from the intestines. Therefore, it is possible to localize the transplant accurately, measure the distance from the skin to the surface of the kidney and determine with precision the angle of the intended pathway of the needle.

Biopsy, Needle↗
PubMed1977

Prospective study of prevalence, incidence, and source of herpesvirus infections in patients with renal allografts.

The prevalence, incidence, and source of infections with different types of herpesviruses were determined prospectively for 25 persons undergoing hemodialysis, 30 allograft recipients, and 16 kidney donors. The prevalence of prior infections with cytomegalovirus (CMV), herpes simplex virus (HSV), and Epstein-Barr virus (EBV) was high (72%-100%) and was similar for healthy persons and those with renal failure. The incidence of infections in patients undergoing hemodialysis was no greater than that before dialysis. In allograft recipients, the incidence of infection with CMV was 73%; HSV, 57%; EBV, 30%; and varicella-zoster virus (clinical), 7%. Ninety-seven percent of the patients developed an infection with one or more herpesviruses. Transfusions, hemodialysis, the allograft, and hospital environment were not significant sources in transmission. Uremia and splenectomy were unimportant in the reactivation of infection. Immunosuppressive drugs possibly algmented by a graft rejection response account for the high incidence of recrudescent infections with CMV and HSV.

Adult↗
PubMed1977

Diagnosis of urine extravasation after renal transplantation.

Urine extravasation in the early postoperative period after renal transplantation is a serious complication requiring expedient surgical intervention. Whereas clinical and laboratory findings are inconclusive, radiologic diagnostic studies have definite value. Routine ultrasound and radioisotope studies were performed on 111 renal transplant patients. In the eight who developed urine extravasation, ultrasound and/or radioisotope studies identified the extravasation in seven cases. Four of the eight were studied by intravenous pyelography and another two were studied by cystography. All results were positive. We recommend use of radioisotope and ultrasound studies for routine postoperative screening with invasive techniques reserved for inconclusive cases.

Adolescent↗
PubMed1977

Experimental and clinical therapy of diabetes by transplantation.

Prevention, delay, or reversal of the microvascular complications of diabetes is the ultimate goal of pancreatic islet cell transplantation. Advances in surgical techniques and in islet isolation procedures have made the achievement of this goal a practical possibility. Microvascular lesions have indeed been prevented and even reversed in successful islet cell transplantation experiments in rats. Successful application of pancreatic islet cell transplantation in the human now awaits the development of effective suppression of rejection.

Animals↗