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Biomedical subjects

R Shapiro

Publications and source records attributed to R Shapiro.

At least 235 records · Page 13Linked to original sources
PubMed1994

Improving results of pediatric renal transplantation.

BACKGROUND: Outcome after renal transplantation in children has been variable. We undertook a retrospective study of our experience over the past five years. STUDY DESIGN: From January 1, 1988, to October 15, 1992, 60 renal transplantations were performed upon 59 children at the Children's Hospital of Pittsburgh. Twenty-eight (47 percent) of the kidneys were from cadaveric donors, and 32 (53 percent) were from living donors. The recipients ranged in age from 0.8 to 17.4 years, with a mean of 9.8 +/- 4.8 years. Forty-six (77 percent) recipients were undergoing a first transplant, while 14 (23 percent) received a second or third transplant. Eight (13 percent) of the patients were sensitized, with a panel reactive antibody of more than 40 percent. Eleven of the 14 patients undergoing retransplantation and seven of the eight patients who were sensitized received kidneys from cadaveric donors. Thirty-three (55 percent) patients received cyclosporine-based immunosuppression, and 27 (45 percent) received FK506 as the primary immunosuppressive agent. RESULTS: The median follow-up period was 36 months, with a range of six to 63 months. The one- and four-year actuarial patient survival rate was 100 and 98 percent. The one- and four-year actuarial graft survival rate was 98 and 83 percent. For living donor recipients, the one- and four-year actuarial patient survival rate was 100 and 100 percent; for cadaveric recipients, it was 100 and 96 percent. Corresponding one- and four-year actuarial graft survival rates were 100 and 95 percent for the living donor recipients and 96 and 69 percent for the cadaveric recipients. Patients on cyclosporine had a one- and four-year patient survival rate of 100 and 97 percent, and patients on FK506 had a one- and three-year patient survival rate of 100 and 100 percent. Corresponding one- and four-year actuarial graft survival rates were 100 and 85 percent in the cyclosporine group, while one- and three-year actuarial graft survival rates were 96 and 84 percent in the FK506 group. The mean serum creatinine level was 1.24 +/- 0.64 mg per dL; the blood urea nitrogen level was 26 +/- 13 mg per dL. The incidence of rejection was 47 percent; 75 percent of the rejections were steroid-responsive. The incidence of cytomegalovirus was 10 percent. The incidence of post-transplant lymphoproliferative disorder was 8 percent. None of the patients on cyclosporine were able to be taken off prednisone; 56 percent of the patients receiving FK506 were taken off prednisone successfully. Early growth and development data suggest that the patients receiving FK506 off prednisone had significant gains in growth. CONCLUSIONS: These results support the idea that renal transplantation is a successful therapy for end-stage renal disease in children. They also illustrate the potential benefits of a new immunosuppressive agent, FK506.

Adolescent↗
PubMed1994

A prospective, randomized trial of FK-506 in renal transplantation--a comparison between double- and triple-drug therapy.

Previous clinical evaluation of FK506 in renal transplantation has demonstrated equivalent patient and graft survival when compared with cyclosporine-based regimens. However, lower steroid and anti-hypertensive mediation requirements and lower serum cholesterol levels have been seen in patients receiving FK506. In August, 1991, a prospective, randomized trial was begun, comparing FK506/prednisone with FK506/azathioprine/prednisone. Two-hundred-and-four adults were entered into this trial between August 1, 1991, and October 11, 1992. The mean recipient age was 43.8 +/- 13.7 years, with a range of 17.6-78.0 years. Sixty-one (30%) recipients received a 2nd, 3rd or 4th transplant, while 35 (17%) had a PRA greater than 40% at the time of transplant. Thirty-three (16%) of the transplants were in recipients over 60 years of age, Thirteen percent of the kidneys were from living donors; 13% of the cadaveric kidneys were from pediatric donors less than 3 years of age and were transplanted en bloc. The mean cold ischemia time was 31.4 +/- 8.4 hours, and the mean donor age was 34 +/- 2.10 years, with a range from 4 months to 75 years. With a mean follow-up of 9 +/- 4 months, the 1-year actuarial patient survival is 93%; for the two-drug group it is 95%, and for the three-drug group it is 91% (p = NS). One-year actuarial graft survival is 86%; in the two-drug group it is 90%, while in the three-drug group it is 82% (p = NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Actuarial Analysis↗
PubMed1994

Renal transplantation at the University of Pittsburgh: the impact of FK506.

1. In an unselected adult renal transplant population, FK506 as the primary immunosuppressive agent yielded one- and 2-year actuarial patient survival rates of 95% and 93% and one- and 2-year actuarial graft survival rates of 89% and 83%, respectively. Forty-nine percent of successfully transplanted patients were weaned off steroids. 2. In pediatric renal transplant patients, FK506 has been associated with 100% one- and 3-year actuarial patient survival rates and 98% and 85% one- and 3-year actuarial graft survival rates, respectively. Sixty-two percent of successfully transplanted patients were taken off prednisone, with dramatic improvements in height. 3. FK506 has been used successfully in rescuing 70-74% of adult or pediatric renal transplant patients with an acute rejection that failed conventional therapy. 4. Kidney/bone marrow transplantation under FK506 therapy has been successfully performed without graft-versus-host disease and with routine augmentation of chimerism. 5. The side effects of FK506 included nephrotoxicity, neurotoxicity, and diabetogenicity; they were comparable to those seen with CsA. 6. FK506 is an important new addition to the immunosuppressive armamentarium in renal transplant patients.

Actuarial Analysis↗
PubMed1993

Modulation of the activity of angiogenin by mutagenesis at Asp-116.

Substitution of Asn, Ala or His for Asp-116 in angiogenin increases its ribonucleolytic activity towards tRNA and, at least in the case of His, its ability to induce blood-vessel formation (Harper, J.W. and Vallee, B.L. (1988) Proc. Natl. Acad. Sci. USA 85, 7139-7143). Six additional Asp-116 mutants have been examined to further probe the basis for this phenomenon. Substitution of Val, Lys, Glu, or Ser increases activity towards tRNA 2-, 4-, 9- and 16-fold, respectively, whereas substitution of Trp and Pro leads to 2- and 10-fold decreases, respectively. Similar changes are seen in activity towards rRNA. Studies of base-cleavage specificity towards dinucleotide substrates (NpN') reveal a change in preference for G vs. A at the N' position when Ser replaces Asp-116 and a diminished preference for C vs. U at the N position. The Pro, Lys and Glu mutants have essentially unchanged angiogenic activity. The results demonstrate that the principal effect of replacing Asp-116 in angiogenin is to modulate enzymatic activity, possibly through an effect on His-114, and suggest that Asp-116 plays a role in controlling specificity.

Amino Acid Sequence↗
PubMed1993

Alteration of the enzymatic specificity of human angiogenin by site-directed mutagenesis.

The molecular basis for the enzymatic specificity of human angiogenin has been investigated by site-directed mutagenesis of Thr-44, Glu-108, and Ser-118--residues corresponding to those thought to be involved in substrate base recognition in the homologous protein, RNase A. Mutations of Thr-44 to Ala, His, and Asp affect both activity and specificity dramatically. The Ala and His replacements decrease activity toward tRNA by factors of 25 and 40, respectively, and reduce cleavage of cytidylyl more than uridylyl dinucleotides. Substitution by Asp does not influence the rate of tRNA and rRNA degradation but alters specificity even more markedly than the other mutations: T44D-angiogenin has 17-40-fold decreased activity toward CpN' dinucleotides and 1.3-1.9-fold increased activity toward UpN', resulting in an inverted order of preference (U > C) compared to native angiogenin. Mutations of Glu-108 to Lys and Gln change activity toward RNA and dinucleotides by no more than 50% and produce slight increases in preference for adenosine vs guanosine at position N' of NpN' substrates. Mutations of Ser-118 to Asp and Arg have a larger effect, decreasing activity by factors of approximately 2 and 4, respectively, toward all substrates examined. These results indicate that: (i) Thr-44 is important for recognition of the pyrimidine moiety at position N, (ii) Glu-108 may make a small contribution to binding the N'-nucleotide, and (iii) Ser-118 has a minor functional role, which appears to involve catalysis rather than nucleotide binding.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiogenesis Inducing Agents↗
PubMed1993

Effects of dietary iron and folate supplementation on the physiological changes produced in weanling rats by sodium saccharin exposure.

Exposure of rats to high dietary levels of sodium saccharin (NaSac) started in utero produce physiological effects at 30 days post-birth that are similar to those found in pups of iron-deficient dams. These similarities suggest that some of the changes due to NaSac are secondary to iron deficiency. The present experiment investigated whether the effects of 7.5% dietary NaSac in the newborn rat could be prevented by dietary iron and/or folate supplementation. The NaSac-related effects prevented by iron supplementation included anaemia, decreased serum iron and folate, increased serum cholesterol and triglyceride and increased serum vitamin E. Folate supplementation prevented NaSac-induced depression of serum folate and increase in serum vitamin E. Although bladder hyperplasia was increased by dietary iron and/or folate supplementation, the majority of the urinary chemistry changes associated with NaSac treatment were not affected. The results show that some physiological changes associated with NaSac treatment in the newborn rat may occur as a consequence of iron deficiency rather than a direct effect of NaSac treatment. These changes may be independent of the urinary and bladder effects, which are not reversed by iron supplementation.

Animals↗
PubMed1993

Nosocomial outbreak of tuberculosis in a renal transplant unit: application of a new technique for restriction fragment length polymorphism analysis of Mycobacterium tuberculosis isolates.

From January 1990 through February 1991, tuberculosis (TB) developed in 10 renal transplant (RT) patients at one hospital; 5 patients died. Possible nosocomial transmission was investigated. Mycobacterium tuberculosis isolates were compared by restriction fragment length polymorphism (RFLP) by a polymerase chain reaction method. The source case occurred in an RT patient (source) who had posttransplant exposure to TB at another hospital. The source patient was rehospitalized on the RT unit; diagnosis of TB and thus isolation precautions were delayed. Epidemiologic and RFLP analysis showed transmission from the source to 5 RT patients and 1 human immunodeficiency virus-infected patient. M. tuberculosis isolates from 4 RT patients had other RFLP patterns. The median incubation period for TB in RT patients was 7.5 weeks (range, 5-11). Bronchoscopy and intubation of the source patient and inadequate ventilation on the RT unit possibly increased transmission. Early detection of TB and effective isolation are essential to prevent nosocomial transmission.

Adult↗
PubMed1993

The histopathological changes associated with allograft rejection and drug toxicity in renal transplant recipients maintained on FK506. Clinical significance and comparison with cyclosporine.

The histopathological changes in 51 renal allograft biopsies from patients immunosuppressed with FK506 were compared with those seen in 30 needle biopsies obtained from patients on cyclosporine. The frequency and severity of rejection episodes were similar in both groups. Tubular vacuolation and myocyte vacuolation were found to be useful morphological markers to monitor short-term drug toxicity associated with both drugs. Long-term administration of FK506 led to striped interstitial fibrosis and arteriolar hyalinosis, similar to that previously documented for cyclosporine. One case each of hemolytic uremic syndrome and necrotizing arteriopathy was noted in patients receiving FK506. FK506 and cyclosporine are structurally unrelated compounds; hence the parallelism observed in their nephrotoxicity profile suggests that the interactions of these drugs with renal tissue involves the operation of two different initial signal-transducing mechanisms, ultimately activating the same final metabolic pathways.

Adult↗
PubMed1993

Frequency of kidney rejection in diabetic patients undergoing simultaneous kidney and pancreatic islet cell transplantation.

An increased frequency of kidney rejection has been reported in diabetic patients who have simultaneous pancreas and kidney transplantation compared with patients who have a kidney transplant alone. Kidney graft outcome is similar in the two groups. The mechanism for increased kidney graft rejection with a simultaneous pancreas graft is not clear. It is ascribed to the immunogenicity of the exocrine pancreas that initiates migration of activated cells from the peripheral blood that are entrapped in the kidney. Since the volume of the transplanted tissue is less in islet transplantation (usually < 2 ml) than in pancreas transplantation, one might not expect an increased frequency of kidney rejection in islet cell recipients. We looked at biopsy-proven kidney rejection episodes in patients who had combined kidney and islet transplants and compared this with the frequency of rejection in diabetic and nondiabetic patients who underwent a kidney transplant alone under the same immunosuppression. Diabetic patients who had kidney islet transplants (n = 9) had a higher frequency of rejection (100%) compared with diabetic patients (n = 107, 55.1%) and nondiabetic patients (n = 327, 65%) who had a kidney transplant alone. The 1-year graft and patient survival rates were not different among the groups. Although the number of patients is small, it would appear that transplantation of a low volume of islet cells with high purity can lead to an increased frequency of kidney rejection. This is unlikely to be explained solely on the basis of fewer antigen matches in these recipients but may reflect the inherent immunogenicity of the purified islet preparations. Alternatively, there may be an effect of their direct infusion into the portal vein.

Adrenal Cortex Hormones↗
PubMed1993

Imaging of en bloc renal transplants: normal and abnormal postoperative findings.

OBJECTIVE: Cadaveric kidneys from donors less than 5 years old, previously considered inferior graft material, are now being successfully transplanted en bloc into children and adults. On the basis of our experience with 132 patients, we describe the general principles of the procedure and review the spectrum of normal and abnormal imaging findings in patients who have undergone this promising transplantation procedure. MATERIALS AND METHODS: Paired cadaveric kidneys obtained from donors less than 5 years old (mean age, 24 months) were transplanted en bloc to 132 patients (mean age, 37 years) at our institution between 1981 and 1991. All available medical, surgical, pathologic, and imaging records were retrospectively reviewed to define the surgical technique, 1-year survival rate of the graft, appearance of the transplant on postoperative imaging studies, and the prevalence of and imaging findings caused by vascular, urinary, infectious, and neoplastic complications after transplantation. Complications were confirmed by a definitive imaging study, surgical exploration, or study of a pathologic specimen. RESULTS: Paired donor kidneys were transplanted en bloc extraperitoneally into the recipient's right or left iliac fossa, with intact portions of the donor aorta and inferior vena cava anastomosed to the recipient's external iliac artery and vein. One-year graft survival was 70% during the first 8 years of the study and 78% during the last 2 years. Postoperative imaging, particularly sonography and scintigraphy, clearly depicted the normal individual kidneys, urinary collecting systems, and en bloc vasculature. Postoperative complications were vascular (arterial stenoses and thromboses, venous thromboses, and pseudoaneurysms) in 18%, urinary (obstruction and anastomotic leak) in 11%, infectious (caliceal fungal balls) in 1%, and neoplastic (posttransplant lymphoma) in 1%. The complications involved one kidney in 60% of the patients and both kidneys in 40%. The imaging findings caused by these complications were similar to those caused by complications occurring after transplantation of single cadaveric kidneys; however, their detection was more difficult because of the complexity of the en bloc graft. CONCLUSION: Because of the shortage of available donor organs, en bloc renal transplantation will most likely become increasingly popular. Familiarity with the imaging appearance of the normal transplant and of posttransplantation complications will allow radiologists to perform effective postoperative imaging evaluations.

Adolescent↗
PubMed1993

Pilot trial of FK 506 in the management of steroid-resistant nephrotic syndrome.

Seven patients with steroid-resistant nephrotic syndrome were treated with FK 506 monotherapy. Four patients were children with focal sclerosing glomerulonephritis (FSGS). Three of these had evidence for chronic progressive renal disease consisting of interstitial fibrosis and tubular atrophy on pretreatment renal biopsies. Two patients had also failed cyclosporin A (CsA), two cyclophosphamide, and one chlorambucil prior to treatment with FK 506. Three patients were adults with mesangial proliferative, membranoproliferative, and membranous glomerulonephritis. Three patterns of response were noted: (1) a reduction in proteinuria to normal levels; (2) partial response (50% reduction) or; (3) no improvement. All patients except one experienced at least a 50% reduction in protein excretion at some time during FK 506 therapy. Two of the children and one adult reduced protein excretion to essentially normal values. One patient had no sustained reduction in protein excretion and is considered to be a treatment failure, although her protein excretion was approximately 50% of pretreatment values intermittently. The drug was generally well tolerated. The most common side-effect was nephrotoxicity, which was reversible. These encouraging results suggest that FK 506 monotherapy may be effective in controlling the proteinuria of some patients with steroid-resistant nephrotic syndrome. The use of this drug may extend our understanding of the role of T lymphocytes and cytokines in the pathogenesis of glomerulonephritis. Further study of this agent in a larger population of patients is warranted.

Adolescent↗