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Biomedical subjects

R Sibley

Publications and source records attributed to R Sibley.

At least 55 records · Page 3Linked to original sources
PubMed1984

Bone-marrow transplantation in the Maroteaux-Lamy syndrome (mucopolysaccharidosis type VI). Biochemical and clinical status 24 months after transplantation.

A 13-year-old girl with the severe form of the Maroteaux-Lamy syndrome (mucopolysaccharidosis Type VI, arylsulfatase B deficiency) has had successful reconstitution with bone marrow from her HLA-MLC-matched sister who had normal arylsulfatase B activity. Full engraftment has been present for 24 months. The following biochemical and clinical changes have occurred: arylsulfatase B activity in peripheral lymphocytes and granulocytes increased to normal levels, and the activity in serial liver-biopsy specimens increased from about 3 per cent of the mean normal level 43 days after transplantation to about 16 per cent at 600 days. Urinary excretion of acid mucopolysaccharide decreased. Ultrastructural evidence of accumulated dermatan sulfate was no longer detectable in bone-marrow cells; in peripheral-blood lymphocytes, granulocytes, or platelets; or in Ito cells of liver. Twenty-four months after engraftment, hepatosplenomegaly was substantially decreased and cardiopulmonary function was normal. Visual acuity and joint mobility were also improved. The patient returned to school and continued to perform well in academic studies. Thus, bone-marrow transplantation provided a source of enzymatically normal cells, which have altered the metabolic and clinical course of the disease.

Adolescent↗
PubMed1984

Fibrochondrogenesis: lethal, autosomal recessive chondrodysplasia with distinctive cartilage histopathology.

Fibrochondrogenesis is a rare, neonatally lethal rhizomelic chondrodysplasia distinguished from other forms of lethal dwarfism by broad long-bone metaphyses, pear-shaped vertebral bodies, and by microscopic changes of cartilage with unique interwoven fibrous septa and fibroblastic dysplasia of chondrocytes. We report the second and third well-documented cases of this apparently autosomal recessive disorder and discuss the differential diagnosis.

Cartilage↗
PubMed1984

No evidence for a specific role of IgM in mesangial proliferation of idiopathic nephrotic syndrome.

To define the relationship of mesangial IgM to various morphologic categories of idiopathic nephrotic syndrome (INS), an analysis of 100 patients was carried out in which five morphologic subgroups were evaluated: group 1, minimal glomerular change (38 patients); group 2, minimal change with focal global sclerosis (18 patients); group 3, focal segmental glomerulosclerosis ( FSG ) (23 patients); group 4, mesangial proliferation (12 patients); group 5, focal segmental glomerulosclerosis with mesangial proliferation (9 patients). Immunohistochemical studies failed to demonstrate any differences between these five groups. The intensities of immunofluorescence and the percentage of tissue samples demonstrating IgM and/or C3 in the glomerular mesangium and subendothelial regions were similar. In addition, the presence or intensity of mesangial IgM did not predict the patients' current status or responsiveness to steroid therapy. Morphologic transitions were observed in patients who had more than one biopsy: one of five in group 2 and two of eight in group 3 developed mesangial proliferation; and nine of ten patients with mesangial proliferation in the first biopsy continued to show this finding in the second. In general, a complete response to steroid therapy and a favorable outcome is less likely in patients with this morphologic abnormality. In nine of the 27 repeat biopsies, there was lack of agreement between the first and second tissue samples with respect to the presence or absence of mesangial IgM. Although mesangial proliferation is a consistent feature of the morphology of certain patients with INS, these studies do not support a unique association with mesangial IgM.

Adolescent↗
PubMed1984

Renal toxicity of mitomycin-C.

The clinical spectrum and the pathological findings of renal toxicity in four patients treated with mitomycin-C are described. Our experience and evidence in the literature indicates that the renal impairment appears to be total-dose-related, with most patients developing renal symptoms after receiving at least 60 mg of mitomycin-C. The renal morphologic changes reveal a glomerular and vascular process similar to that seen in a number of clinical situations associated with the hematologic findings of microangiopathic hemolytic anemia. In patients with malignant disease, it may be that the use of mitomycin-C either alone or in combination with other drugs causes endothelial vascular damage with resultant activation of the coagulation system. There is evidence that early detection of the renal impairment and withdrawal of mitomycin-C might halt further progression of renal failure.

Adult↗
PubMed1984

Transluminal angioplasty evaluated by electron microscopy.

To gain more understanding about the changes that follow balloon angioplasty, an electron and light microscopic study was carried out in normal canine arteries. Thirty-five arterial segments were dilated with balloon catheters. Early changes consisted of denudation of the intima with widespread necrosis of myocytes and dehiscence of collagen fibers. After three days, myocytes had disappeared leaving empty spaces and edematous ground substance. After two weeks, reendothelization occurred and there was evidence of intimal hyperplasia persisting up to two months. Repair of the dilated arterial segments occurred by proliferation of myocytes, formation of intima, and proliferation of collagen. In two to three months, repair of the intima and media was completed. After six months, dilated segments were characterized by persistent intimal hyperplasia and increased collagen content in the media.

Angioplasty, Balloon↗
PubMed1984

The pathologic basis of angioplasty.

Traditionally it has been said that transluminal angioplasty increases lumen diameter by compression and remodeling of atheromatous material. Recently, a new concept explaining the mechanics of angioplasty was described which challenges the classic concept of Dotter. It was argued that arterial balloon dilatation is achieved by intimal disruption and overstretching of the arterial wall, not by remodeling of atheromatous material.

Angioplasty, Balloon↗
PubMed1984

Renal allograft failure due to recurrent dense intramembranous deposit disease.

Dense intramembranous deposit disease (DIDD) almost universally recurs in renal allografts. However, the 29 previously reported cases suggest that recurrent DIDD rarely results in graft failure. We studied the clinical course and renal histology of the 6 patients with DIDD who have received renal allografts here since 1967. All patients had characteristic findings of DIDD in their native kidneys by light, immunofluorescence and electron microscopy. Seven grafts in 4 patients failed and histological evaluation showed that 5 of these allografts in 4 patients were lost due to recurrent disease. They all demonstrated marked mesangial proliferation with crescents but minimal acute interstitial or vascular changes of rejection. Patients with graft failure due to recurrent disease were male and developed recurrent nephrotic syndrome. The 2 patients with rapidly progressive glomerulonephritis (RPGN) in their native kidneys lost the transplanted kidney due to recurrent disease within 1 year. This study suggests that recurrence of DIDD in renal allografts is a more serious problem than previously appreciated, especially in patients with RPGN.

Adolescent↗
PubMed1983

The value of needle renal allograft biopsy. I. A retrospective study of biopsies performed during putative rejection episodes.

Following renal transplantation, immunosuppression is usually increased to treat presumed rejection episodes. However, a) many conditions mimic rejection in the post-transplant period, and b) many rejection episodes are irreversible. As increased immunosuppressive therapy is associated with an increased risk of infection, it would be ideal to limit antirejection therapy to only the rejection episodes that are reversible. The role of percutaneous allograft biopsy was studied as an aid to decide which patients to treat for rejection, to limit unnecessary immunosuppression and to predict allograft survival. One hundred thirty-five patients with suspected rejection underwent 206 allograft biopsies without complication. Two hundred four biopsies were available for study. Biopsies were coded on a 1-4 scale (minimal, mild, moderate, severe) for acute and chronic tubulointerstitial infiltrate and vascular rejection, as well as no rejection (e.g., recurrence of original disease). Treatment decisions were made on the basis of the biopsy combined with clinical data. All patients have been followed two years and outcome correlated with biopsy findings (death, nephrectomy, and return to dialysis defined as kidney loss). The results were the following: 1) biopsies represented changes within the kidney. Of 16 kidneys removed within one month of biopsy, no nephrectomy specimen showed less rejection than that seen on biopsy. 2) Eighty-one biopsies (39.7%) led to tapering or not increasing immunosuppression (either no rejection, minimal rejection, or irreversible changes). 3) Kidneys having either severe acute or chronic vascular rejection (less than 30% function at three months) had significantly (p less than 0.05) decreased survival three to 24 months postbiopsy than those with minimal or mild vascular rejection or tubulointerstitial infiltrate (83% function at three months). 4) Kidneys with moderate chronic vascular rejection and those with severe acute tubulointerstitial infiltrate had significantly (p less than 0.05) decreased survival at six to 24 months. 5) Kidneys with moderate chronic vascular rejection (MCV) without an acute infiltrate (ATI) had significantly better survival than those having both MCV and ATI. 6) Similarly, kidneys having severe ATI alone had better survival than those with ATI plus vascular rejection. It was concluded that a) percutaneous allograft biopsy can be done without graft loss or infection; b) biopsy represents changes throughout the kidney; c) biopsy aids in deciding when to treat for rejection and in deciding when to withhold increased immunosuppression, and d) allograft biopsy predicts the outcome of treatment of a rejection episode.

Biopsy, Needle↗
PubMed1982

Renal vascular lesions after chemotherapy with vinblastine, bleomycin, and cisplatin.

A 30 year old man with metastatic embryonal carcinoma became hypertensive during vinblastine, bleomycin, and cisplatin therapy. Three months after completion of therapy, accelerated hypertension occurred (blood pressure 210/140 mm Hg). Nitroprusside failed to control the hypertension, but captopril resulted in a prompt and sustained normalization of the blood pressure. The plasma renin activity was markedly elevated before therapy. Renal biopsy disclosed "onionskin" narrowing of the interlobular arteries and fibrin thrombosis of a majority of the afferent arterioles. A form of drug-induced renovascular hypertension is suggested.

Adult↗
PubMed1981

Ultrasound in acute renal transplant rejection.

Gray-scale ultrasound and biopsy were compared in 63 patients with suspected acute kidney allograft rejection. Sonographic findings of increased size and decreased echogenicity of renal pyramide, focal zones of sonolucency in renal cortex, and patchy sonolucent areas involving both cortex and medulla with coalescence correlated well with biopsy in 46 out of 50 patients (92%) treated for acute rejection (sensitivity = 0.92). Abnormal perirenal fluid collection was encountered in three out of 60 patients (5%). Out of 63 sonographic studies, 10 (16%) gave either false positive (6) or false negative (4) results for an overall accuracy of 85%.

Biopsy↗
PubMed1981

Renal failure as a complication of acute antihypertensive therapy.

Adult patients with long-standing hypertension have been reported to experience an impairment in renal function when treatment with potent vasodilating agents is initiated. To document that this sequence may occur in children as well, we report the case of a 4-year-old boy with renal disease in whom reduction of blood pressure to normal levels was accompanied on three occasions by oliguric renal failure. During each episode, the correlation between reduction in blood pressure and increase in serum creatinine level was significant (P less than .05); furthermore, the slope of the relationship was similar with each episode. This phenomenon suggests an impairment of renal autoregulation in this patient. Maintenance of normal blood pressure for several months was accompanied by a gradual return of renal function to pretreatment levels. This case suggests that particular attention should be paid to renal function during the initiation of antihypertensive therapy, particularly in patients with renal vascular damage. Present evidence does not appear to warrant modification of the current therapeutic philosophy of aggressive management in patients with severe hypertension.

Acute Kidney Injury↗
PubMed1980

Renal artery aneurysms: an angiographic sign of transplant rejection.

Intrarenal arterial aneurysm is an uncommon manifestation of allograft rejection. We present two cases of transplant rejection with aneurysm formations. One case simulated polyarteritis nodosa, while in the other, the aneurysm appeared similar to those seen in post-stenotic arterial dilatation.

Adult↗