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Biomedical subjects

B Chavers

Publications and source records attributed to B Chavers.

36 records · Page 2Linked to original sources
PubMed1990

Renal transplantation in infants.

The timing of renal transplantation in infants is controversial. Between 1965 and 1989, 79 transplants in 75 infants less than 2 years old were performed: 23 who were 12 months or younger, 52 who were older than 12 months; 63 donors were living related, 1 was living unrelated, and 15 were cadaver donors; 75 were primary transplants and 4 were retransplants. Infants were considered for transplantation when they were on, or about to begin, dialysis. All had intra-abdominal transplants with arterial anastomosis to the distal aorta. Sixty-four per cent are alive with functioning grafts. The most frequent etiologies of renal failure were hypoplasia (32%) and obstructive uropathy (20%); oxalosis was the etiology in 11%. Since 1983 patient survival has been 95% and 91% at 1 and 5 years; graft survival has been 86% and 73% at 1 and 5 years. For cyclosporine immunosuppressed patients, patient survival is 100% at 1 and 5 years; graft survival is 96% and 82% at 1 and 5 years. There was no difference in outcome between infants who were 12 months or younger versus those who were aged 12 to 24 months; similarly there was no difference between infants and older children. Sixteen (21%) patients died: 5 after operation from coagulopathy (1) and infection (4); and 11 late from postsplenectomy sepsis (4), recurrent oxalosis (3), infection (2), and other causes (2). Routine splenectomy is no longer done. There has not been a death from infection in patients transplanted since 1983. Rejection was the most common cause of graft loss (in 15 patients); other causes included death (with function) (7), recurrent oxalosis (3), and technical complications (3). Overall 52% of patients have not had a rejection episode; mean creatinine level in patients with functioning grafts is 0.8 +/- 0.2 mg/dL. Common postoperative problems include fever, atelectasis, and ileus. At the time of their transplants, the infants were small for age; but with a successful transplant, their growth, head circumference, and development have improved. Transplantation in infants requires an intensive multidisciplinary approach but yields excellent short- and long-term survival rates that are no different from those seen in older children or adults. Living donors should be used whenever possible. Patients with a successful transplantation experience improved growth and development, with excellent rehabilitation.

Adolescent↗
PubMed1989

Allograft renal vascular thrombosis--lack of increase with cyclosporine immunosuppression.

Several recent reports have demonstrated an increased incidence of allograft renal vascular thrombosis in patients receiving cyclosporine alone or as part of multiple drug regimens when compared with patients receiving azathioprine (AZA) and prednisone (P). To determine whether CsA therapy is indeed a risk factor for renal artery or vein thrombosis, we examined the incidence of these complications in 224 adult renal allograft recipients who were prospectively randomized and stratified by risk to treatment with either CsA-P (n = 117) or AZA-P-antilymphocyte globulin (n = 107) between September 1980 and October 1983, and in 452 adult and 87 pediatric patients on triple (AZA-P-CsA) or quadruple (AZA-P-CsA-ALG) therapy protocols between July 1984 and November 1987. In the randomized trial, one of 107 AZA-P-ALG patients (0.9%) and two of 117 CsA-P patients (1.7%) developed renal vein thrombosis (P = 0.94), and there were no cases of arterial thrombosis. Though CsA levels were elevated in one of the two CsA-treated patients at the time of their events, and both these patients demonstrated other predisposing factors for thrombosis. In the triple/quadruple therapy era, there were no cases of renal vein thrombosis, and the only case of renal artery thrombosis occurred in a pediatric recipient who was not receiving CsA at the time. These data, when taken together with a critical review of the conflicting literature, strongly suggest that factors other than immunosuppression with CsA, including surgical technique, allograft rejection, use of multiple artery and/or pediatric donor kidneys, and postoperative hypotension, are important in the pathogenesis of allograft renal vascular thrombosis. It seems possible, however, that high initial dosing of CsA might trigger this complication in the early posttransplant period when other predisposing factors are present.

Antilymphocyte Serum↗
PubMed1989

Mesangial expansion as a central mechanism for loss of kidney function in diabetic patients.

Diabetic nephropathy leading to kidney failure is a major complication of both type I (insulin-dependent) and type II (non-insulin-dependent) diabetes mellitus, and glomerular structural lesions (especially expansion of the mesangium) may constitute the principal cause of decline in kidney function experienced by a significant fraction of diabetic patients. Although the biochemical bases of these mesangial abnormalities remain unknown, an understanding of the natural history of diabetic nephropathy from a combined structural and functional approach can lead to greater pathophysiological insight. Work in animals has supported the concept that the metabolic disturbances of diabetes mellitus cause diabetic nephropathy, with structural and functional lesions prevented or reversed with improved or normalized glycemic control. Additional research must address this fundamental issue in humans, especially the response of advancing mesangial lesions to improved glycemic control. Factors not directly related to the metabolic perturbations of diabetes may serve to accelerate or diminish the pathophysiological processes of diabetic nephropathy. The elucidation and management of these factors, when coupled with improved glycemic control, may moderate the development or progression of diabetic kidney lesions in humans.

Albuminuria↗
PubMed1987

Low-dose cyclosporine therapy combined with standard immunosuppression in pediatric renal transplantation.

A new immunosuppressive regimen combining anti-lymphocyte globulin, azathioprine, prednisone, and low doses of cyclosporine was used in 28 children aged 9 months to 17 years (mean 5.8 years) who received primary renal allografts between July 1, 1984, and September 25, 1986. After a mean follow-up of 17.3 months, the patient and graft survival is 100% (18 of 18) for mismatched related kidneys, and 90% (nine of 10) for cadaver kidneys. The single graft failure was the result of a death from technical complications. Serum creatinine concentration after transplantation ranged from 0.3 to 1.7 mg/dL (mean 0.85 mg/dL). The probability of a rejection episode in the first year was 45% and 60% for mismatched-related and cadaver kidneys, respectively. Cyclosporine nephrotoxicity was recognized in only one (3.7%) of 27 children, and was rapidly reversed after cyclosporine was discontinued. An initial group of nine children was weaned from cyclosporine therapy 6 to 12 months after transplantation, but two (22%) had rejection episodes. Our preliminary experience suggests that the use of a quadruple immunosuppressive regimen for both living related and cadaver renal transplants in children is associated with an improved graft function rate and a low incidence of complications.

Adolescent↗
PubMed1987

Observations of glomerular epithelial cell structure in patients with type I diabetes mellitus.

Overt proteinuria is a hallmark of diabetic nephropathy while microalbuminuria is thought to be a predictor of later onset of diabetic nephropathy. Yet the mechanisms for abnormal urinary protein leak in diabetes have not been defined. We studied 28 patients with type I diabetes for 7 to 33 years. Creatinine clearance, urinary albumin excretion rate (UAE), and multiple blood pressures were obtained in each patient. A renal biopsy was performed in each patient and in 28 normal subjects. Quantitative stereology was used to determine foot process (FP) width, filtration slit length density (FSLV) and filtration slit length/glomerulus (FSLG). FP width was slightly wider than normal in diabetic patients with UAE less than 250 mg/24 hr while FP was significantly wider than both of these groups in diabetics with UAE greater than 250 mg/24 hr. FSLV and FSLG were similar in normals and diabetics with UAE less than 250 mg/24 hr but both were reduced in diabetics with UAE greater than 250 mg/24 hr. UAE correlated with FP width (P less than 0.05), FSLG (P less than 0.01) and most precisely and FSLV (P less than 0.001). Diabetics with microalbuminuria had values for all the structural parameters measured here not different from diabetics with UAE in the normal range. Perturbations of epithelial cell structure are present in diabetes mellitus especially in patients with nephropathy. The exact relationships between albuminuria and epithelial cell structure remains to be elucidated.

Adult↗
PubMed1987

Renal transplantation at the University of Minnesota during the 1980s.

1. There have been 1,225 renal allografts performed at the University of Minnesota between January 1, 1980 and May 31, 1987. Significant risk factors for graft survival include donor type, retransplantation, and age at time of transplant. In addition, diabetes is a significant risk factor in patient survival. 2. Three immunosuppressive regimens have been used during this time period: AZA + P + ALG, CsA + P, and CsA + AZA + P (+ ALG for CAD grafts). The 3 protocols have been received by 411, 205, and 356 primary renal allograft recipients, respectively. No overall differences between the therapies exist with respect to graft or patient survival. However, females, recipients of CAD organs (especially the recipient with diabetes), and patients 18-50 years of age at transplant have improved graft survival results using CsA + AZA + P (+ ALG). Females and the 18-50-year-old recipients also have improved results with respect to patient survival. 3. The 3 protocols [AZA + P + ALG; CsA + P; and CsA + AZA + P + ALG] have been used for 125, 112, and 174 primary recipients of CAD organs, respectively. Recipients of CsA + AZA + P + ALG have significantly better graft survival overall in the diabetic and poorly matched subgroups. Other high-risk (but small sample size) subgroups show statistically nonsignificant, but clinically important, improvements. These groups include patients over 50 years of age, patients with preformed antibodies, as well as those with compatible ABO blood types. Similar trends exist with respect to patient survival. 4. Risk factor analysis of all patients receiving CsA + AZA + P (+ ALG) indicates that donor type, retransplantation, and age at the time of transplant are still serious risk factors for graft survival. Only age at transplant influences patient survival significantly. 5. The failure to find any significant risk factors in primary recipients of CAD organs in the CsA + AZA + P(+ ALG) era, combined with the generally consistent good graft and patient survival rates, suggest that the traditionally high-risk patient can be successfully transplanted with excellent results. 6. Pediatric patients can be successfully transplanted with results equivalent to 18-50-year-old patients and better than those recipients over 50 years of age at the time of transplant. Random transfusions and combination therapy are at least as good as DST and AZA + P + ALG.

Adolescent↗
PubMed1985

Skeletal muscle basement membrane in maturity-onset diabetes in the young.

We have studied skeletal muscle capillary basement membrane width (CBMW) and intensity of skeletal muscle extracellular basement membrane staining for albumin and IgG in eight families with maturity-onset diabetes in the young (MODY). Ninety-two MODY patients were identified. Sixty-three of these patients, 33 relatives with nondiagnostic oral glucose tolerance studies, and 61 normoglycemic relatives were studied for glucose and insulin. Twenty-six of these MODY patients, 20 normoglycemic relatives, and 16 unrelated normal controls had skeletal muscle capillary morphologic studies. The muscle capillary basement membrane was significantly increased in MODY patients younger than 40 yr when compared with unrelated normal subjects and relatives of the same age (P less than 0.001). However, in these families, the CBMW of MODY patients showed no significant thickening with age (slope = 0.45, P less than 0.14), as expected and seen in the normal subjects and in the normoglycemic relatives of the patients (slope = 1.21, P less than 0.001). The slope derived from the linear regression of age and CBMW in MODY patients (0.45 +/- 0.29) was significantly less (P less than 0.05) than that of the nondiabetic subjects (1.21 +/- 0.19). The mean intensity of skeletal muscle extracellular basement membrane staining for albumin was higher in MODY patients (1.1 +/- 0.15) than in unrelated normal subjects (0.7 +/- 0.1, P less than 0.025) and normal MODY family members (0.6 +/- 0.08, P less than 0.01). The unexpected absence of basement membrane thickening with age in the MODY patients may explain the paucity of vascular complications that have been reported by some.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1984

Albumin deposition in dermal capillary basement membrane in parents of type 1 (insulin-dependent) diabetic patients.

Skin biopsies were performed to examine dermal capillary basement membranes for albumin by immunofluorescence microscopy in children and young adults with Type 1 (insulin-dependent) diabetes from simplex and multiplex families, their non-diabetic parents and control subjects. Circumferential vessel staining for albumin was 12.0 +/- 14.4% (mean +/- SD) in diabetic patients from multiplex families, 18.8 +/- 20.0% in diabetic patients from simplex families, and 18.5 +/- 24.2% in unaffected parents from simplex families. These values were significantly higher (p less than 0.005) than those obtained in unaffected parents from multiplex families (0.4 +/- 0.9%) or control subjects (0.8 +/- 1.7%). There was no statistically significant difference between Type 1 diabetic probands from simplex or multiplex families and unaffected parents from simplex families. In the simplex families, positive capillary staining for albumin was present only in parents from families in which the diabetic proband had positive staining. In the parents, the presence of dermal capillary staining for albumin did not correlate with an abnormal glucose tolerance test or the presence of cytoplasmic islet cell antibodies. These observations suggest an abnormality in the dermal capillary basement membrane in some unaffected parents of Type 1 diabetic patients from simplex families.

Adolescent↗
PubMed1981

Albumin deposition in dermal capillary basement membrane in insulin-dependent diabetes mellitus. A preliminary report.

Skin specimens obtained from 24 insulin-dependent diabetics (IDD) and 35 controls were examined by immunofluorescence (IF) microscopy. An increased percentage (greater than 8%) of dermal vessel basement membranes (BM) showing circumferential fluorescence for albumin was observed in 18 of 24 IDD (duration of diabetes 1.5-33 yr) and 1 of 35 controls. Dual label studies using fluorescein-conjugated anti-human albumin and rhodamine-conjugated anti-human BM confirmed that localization of albumin was within the BM. These studies suggest that increased albumin localization in extracellular BM may be widespread in diabetes.

Adolescent↗