PubMed Health⌕ Search

Biomedical subjects

R Pollak

Publications and source records attributed to R Pollak.

At least 109 records · Page 6Linked to original sources
PubMed1988

Erythrocythemia following renal transplantation: influence of diuretic therapy.

Post-transplant erythrocythemia (PTE) is a common finding in renal allograft recipients, although the etiology of this disorder has not been clearly established. We identified 22 patients (9.8%) with PTE from among 225 renal transplant recipients followed for an average of 5.5 years. To characterize possible predisposing factors and to study the clinical significance of PTE, these patients were compared with a control group matched for age, race, sex and etiology of renal failure. Plasma volume (PV) and red blood cell mass (RBCM) were measured in the majority of patients with PTE. Peripheral serum erythropoietin (Ep) levels were determined in the majority of patients in the control and PTE groups. PTE occurred an average of 11.4 months after transplantation. Risk factors for the development of PTE were pretransplant hypertension, retention of native kidneys, higher pretransplant hematocrit, and diuretic use for treatment of post transplant hypertension. Ep levels in the PTE and control groups were not significantly different. Twenty of the 22 patients with PTE were receiving concurrent diuretic therapy, and hematocrits fell to normal levels in all of these patients following cessation or dose reduction of diuretic. No other treatment of PTE was utilized, excluding the phlebotomy of a single unit of blood from one patient. No thromboembolic complications were noted during the follow-up period. We conclude that PTE is frequently induced by overzealous diuretic therapy for treatment of post-transplant hypertension. Discontinuation or reduction of diuretic therapy results in resolution of PTE in nearly all patients. From this experience we have developed an algorithm for the investigation and management of PTE.

Adult↗
PubMed1988

Relationship between head dimensions and body length in the context of mental retardation.

The relationship and possible disproportion between different cranial dimensions--head length, head circumference and biparietal diameter--body length and developmental status in normocephalic children were studied in 166 mentally retarded and 471 normal control subjects, between the ages of 3 months and 6 years. When the total cohort was analyzed, all dimensions, particularly head length, were found to be significantly reduced in the study group compared with the controls. Stratification into three age-groups revealed that in the 3- to 15-month-old subjects, head length was the most significantly reduced dimension, while in the older children body length was more significant, followed by head length. Further discriminant analysis resulted in a formula consisting of only three factors--body length, head length and age. Head circumference and biparietal diameter were noncontributory. This investigation did not support the concept of a disproportionately small head compared with height in normocephalic mentally retarded children, but rather a general growth failure mostly affecting height and head length.

Body Height↗
PubMed1988

The acquisition of factual knowledge and the role of the didactic conference in a surgical residency program.

Conferences and seminars are mandated integral components of modern surgical residency programs. We studied the attendance records of house staff at these seminars, as well as an objective measure of cognitive performance (scores achieved in the ABSITE) to determine the role of the teaching seminar in the acquisition of factual knowledge by residents. Seventy five to 85 residents attended weekly scheduled seminars conducted by faculty on a wide range of surgical topics. Attendance records were kept for postgraduate years 1-5 (PGY1-PGY5) and the percentage of residents attending at all conference encounters was calculated. Individual resident ABSITE scores were pooled for each postgraduate year, and expressed as a mean (+/- standard deviation). PGY1 and PGY2 house staff attended conferences poorly (32% and 25% respectively). A marked increase to 56 per cent was noted for the PGY3 level (P less than 0.001), but failed to rise thereafter in the PGY4 and PGY5 years (56% and 52%). ABSITE scores rise with time and progressive seniority, although mean scores remain constant for given postgraduate years. Varying somewhat with the graduating class, PGY5 scores tend to be substantially better than in the PGY1 and PGY2 years. No correlation could be demonstrated between the patterns of conference attendance and the ABSITE scores for each graduating class (r = 0.761; P greater than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Educational Measurement↗
PubMed1987

Cytomegalovirus as a risk factor in living-related renal transplantation. A prospective study.

Forty-four living-related donor kidney (LRD) recipients (19 HLA-identical and 25 haploidentical) were followed prospectively to determine the posttransplant incidence and sequelae of cytomegalovirus (CMV) infection as they relate to the CMV status of recipients and donors. CMV titers were measured in all patients before transplantation by an immunofluorescent assay (IFA). Recipients similarly had CMV titers measured at selected intervals after transplant and during febrile episodes. Appropriate viral cultures were simultaneously performed. Laboratory evidence of infection was correlated with symptoms and signs of active CMV disease. Mean follow-up period was 20 +/- 12 months with a range of 3-51 months. Three patients were excluded due to early acute rejection resulting in graft loss. Twenty-eight of 41 donors (68%) and 22 of 41 recipients (54%) had positive CMV titers before transplantation. Six of 41 recipients (15%) subsequently developed clinical and laboratory evidence of CMV infection: three of 19 seronegative recipients and three of 22 seropositive recipients. All six patients received kidneys from seropositive donors. Four patients had severe CMV disease (2 seronegative, 2 seropositive), whereas two patients had leukopenia and fever only. Two patients with severe CMV infections subsequently lost their grafts due to unrelated causes. Overall, actual patient and graft survival of the entire group is 95% and 82%, respectively. In conclusion, individuals who receive LRD kidneys from seronegative individuals are unlikely to develop CMV infection, and transplantation of seropositive LRD kidneys may be associated with transmission of CMV in susceptible recipients regardless of their serologic status. With appropriate management of CMV illness in the posttransplant period, LRD kidney donation is safe and efficacious and should not be discouraged on the basis of pretransplant CMV serology in any donor-recipient pairing.

Cytomegalovirus↗
PubMed1987

Alternative antirejection treatment with steroids or antilymphoblast globulin in renal transplant patients receiving cyclosporine.

An alternative antirejection protocol using corticosteroids or ALG for reversal of initial acute rejections was studied during a 2-year period in 112 mismatched renal transplant recipients receiving CsA. The majority of patients were cadaver transplant recipients. Thirty-five initial episodes of acute rejection occurred; twelve patients with early or histologically severe rejection were treated with ALG and 23 patients with late, nonsevere rejection received corticosteroid therapy. The overall success rate was approximately 90%, with 21 of 23 corticosteroid-treated patients and ten of 12 ALG-treated patients responding to therapy. The two treatment modalities did not differ with respect to subsequent hospital admissions for fever, second rejections, graft survival, or patient survival. Corticosteroid-treated patients realized significant cost savings and required a shorter hospital stay when compared to ALG-treated patients. An alternative antirejection treatment protocol may be highly effective, safe, and cost beneficial.

Adrenal Cortex Hormones↗
PubMed1987

Conversion from cyclosporine to azathioprine improves renal function without increased risk of graft failure.

Thirty of 110 HLA-mismatched renal allograft recipients were converted from CsA to Aza due to CsA nephrotoxicity or side effects, persistent posttransplant ATN, noncompliance, or patient desire to reduce the cost of maintenance immunosuppression. The majority of patients studied were cadaver transplant recipients. Renal function improved significantly in all patients following conversion. Converted patients did not demonstrate an increased incidence of rejection or hospitalization for fever or infection when compared with nonconverted, matched controls. The rate of allograft loss in converted patients did not differ from that of all nonconverted patients during the study period. The monthly cost of maintenance immunosuppression was significantly less in converted patients, resulting in an annual savings of $2,489 per patient. Posttransplant conversion from CsA to Aza appears to be safe and cost-beneficial.

Adult↗
PubMed1987

Optimizing cyclosporine use in pediatric patients by measuring pretransplant blood levels.

A method for measuring pretransplant CsA levels to predict posttransplant pharmacokinetic behavior was studied in a total of seven pediatric patients. Comparison of drug levels and single-dose pharmacokinetic characteristics in the pretransplant and posttransplant study periods suggest that this method (1) is useful in predicting early posttransplant blood levels and beta-phase half-life; (2) may prevent early episodes of acute allograft rejection associated with subtherapeutic cyclosporine immunosuppression; and (3) may identify those patients who should not be empirically treated with only cyclosporine and prednisone in the early posttransplant period.

Adolescent↗
PubMed1986

The splenic microenvironment and self recognition as factors in allograft rejection in rats. A study using indium-111-labeled cells.

Splenectomy facilitates organ allograft survival in some rat strains, and in weak donor-recipient histoincompatible pairs. We have found using a heart spleen "twin" graft model, using ACI rats as recipients and Lewis rats as donors, that the transplanted heart will survive in most recipients after delayed host splenectomy. The presence of a viable mass of splenic tissue will allow rejection to proceed only when the transplanted spleen is of host origin, and not when it comes from the donor (i.e., when it is allogeneic). The use of 111In-labeled cells has allowed us to show that lymphocyte traffic and trapping is markedly altered in the transplanted allogeneic spleens, when compared with control transplanted syngeneic spleens. Thus, despite the presence of the splenic "microenvironment," cardiac allograft rejection does not occur in the absence of syngeneic splenic tissue. We conclude that the role of the spleen in the immune response is to facilitate the recognition of self and the acquisition of alloreactivity in weak responder rat strains and donor-recipient pairs.

Animals↗
PubMed1986

Anatomic abnormalities of cadaver kidneys procured for purposes of transplantation.

Over a 7-year period the authors studied the vascular and ureteric anomalies of kidneys procured from brain dead, heart-beating cadavers for the purposes of transplantation. Four hundred donors had a bilateral nephroureterectomy performed using an en-bloc technique, followed by fine anatomical dissection in cold saline slush solution. Thus, 800 kidneys were available for study. Single renal arteries were found in 72 per cent of the kidneys, with multiple arteries occurring in 28 per cent. The renal veins showed a more uniform anatomical pattern and were single in 92 per cent of instances. There were nine ureteral anomalies, all duplications, being just 1 per cent of the total number studied. Sex, race, and blood group of the donor did not significantly influence the number of anomalies seen. In sum, anatomical variants were noted in 197 (49.3%) donors, 69 (17.3%) with bilateral anomalies and 128 (32.0%) with unilateral anomalies. A knowledge of these anatomical variants will allow surgeons responsible for organ procurement to proceed with caution and so prevent wastage of cadaver kidneys due to technical misadventures.

Adolescent↗
PubMed1985

Techniques for perfusion and storage of heterotopic heart transplants in mice.

Organ pretreatment prior to transplantation has assumed increasing importance. We studied the ability to preserve and perfuse hearts in well-defined genetic mouse models, prior to heterotopic engraftment. Hearts were manually perfused through the aortic root and stored in a variety of cold solutions or were perfused using a continuous perfusion pump. Different electrolyte solutions, mouse strains, perfusion, and storage times as well as perfusion volumes were studied. Treated hearts were than transplanted heterotopically and short- and long-term function assessed. Hearts stored for more than 1 hour in cold solutions (saline 0.9%, or lactated Ringer's) failed to function. Hearts perfused with 0.25-0.4 ml of cold solution for a maximum of 30 minutes functioned well after transplantation. C3H (H-2k) mice provided the most resilient hearts. We conclude that short-term perfusion or storage of mouse hearts is feasible and should provide an excellent model for the study of organ pretreatment with monoclonal antibodies or other agents prior to transplantation.

Animals↗