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Biomedical subjects

S M Mauer

Publications and source records attributed to S M Mauer.

At least 55 records · Page 3Linked to original sources
PubMed1992

Renal structure and function in insulin-dependent diabetes mellitus in man.

PURPOSE: To review renal pathological changes in diabetes, which include thickening of all renal extracellular basement membranes and the mesangial matrix and, to a lesser extent, mesangial cell expansion. CRITICAL RENAL LESIONS IN DIABETIC NEPHROPATHY: Two renal lesions appear critical in diabetic nephropathy. Mesangial expansion out of proportion to the size of the glomerulus is inversely related to proteinuria, hypertension and a declining glomerular filtration rate. Arteriolar hyalinosis is related to global glomerulosclerosis and both are correlated with the clinical features of nephropathy. By the time renal dysfunction is clinically detectable, these lesions tend to be advanced. Interstitial volume may be increased in insulin-dependent diabetes mellitus, particularly in areas containing sclerotic glomeruli or marked tubular atrophy. FUTURE RESEARCH: Longitudinal studies of renal structure and function and a simultaneous study of potential risk factors and pathways of injury are necessary to develop more refined predictors and clearer pathogenic concepts of this important diabetic complication.

Diabetes Mellitus, Type 1↗
PubMed1992

Recurrence of disease in patients retransplanted for focal segmental glomerulosclerosis.

The natural history of focal segmental glomerulosclerosis in patients retransplanted after loss of a primary allograft is not well established. We studied 14 patients with FSGS who were retransplanted between April 1964 and September 1990 to determine if recurrence in a second or subsequent allograft could be predicted. In this group, 8 of the primary allografts were lost to recurrent disease and 6 to rejection. None of the 6 patients who lost their primary allograft to rejection without evidence of recurrent FSGS suffered recurrent disease after retransplantation. In contrast, 3 of the 8 patients who lost their primary allograft rapidly to FSGS suffered recurrent disease and loss of function in all subsequent allografts. The remaining 5 patients had prolonged function of the primary allograft ranging between 4 and 10.5 years, despite recurrence of FSGS. Of these 5 patients, 2 have excellent renal function after retransplantation without recurrence of FSGS in the secondary allograft at 9 and 10.5 years posttransplant; 2 have lost their secondary allograft to recurrent FSGS, but are free of recurrence in the third allograft at 0.5 and 5.8 years postoperatively; 1 maintains a serum creatinine level of 1.9 mg% despite recurrence of FSGS in the secondary allograft at 1 year postoperatively. Our data show that, without recurrence of FSGS in the primary allograft, further renal transplants will be free of recurrent disease. Based on this finding, we advocate use of living-related donors for second transplants in these patients. With rapid recurrence of FSGS and subsequent accelerated loss of the primary allograft, further renal transplants carry a high likelihood of recurrent FSGS and graft loss. A substantial proportion of patients with recurrent FSGS in the primary allograft will have prolonged renal function, and are likely to have excellent results with subsequent allografts.

Adolescent↗
PubMed1992

Renal structure and function in insulin-dependent diabetes mellitus and type I membranoproliferative glomerulonephritis in humans.

Renal pathological changes of diabetes include thickening of all renal extracellular basement membranes and the mesangial matrix and, to a lesser extent, mesangial cell expansion. Two renal lesions appear critical in diabetic nephropathy. Mesangial expansion out of proportion to the size of the glomerulus is related to proteinuria, hypertension, and declining GFR. Arteriolar hyalinosis is related to global glomerulosclerosis, and both are correlated with the clinical features of nephropathy. By the time renal dysfunction is clinically detectable, these lesions tend to be advanced. Interstitial volume may be increased in insulin-dependent diabetes mellitus, particularly in areas containing sclerotic glomeruli or marked tubular atrophy. Parallel findings were documented for type I membranoproliferative glomerulonephritis in which the increased mesangial volume fraction was related to decreased GFR, increased glomerular permeability to protein, and hypertension. As in diabetes, the cortical interstitial volume fraction is correlated with functional abnormalities in type I membranoproliferative glomerulonephritis. Thus, in both of these chronic glomerular disorders, mesangial expansion and interstitial expansion are associated with disordered renal function. Thus, it is not true that glomerular structural changes correlate poorly with glomerular function. Whether it is the glomerular or interstitial pathology or both that is causally responsible for the dysfunction requires further study.

Diabetes Mellitus, Type 1↗
PubMed1992

Glomerular structure in IDDM women with low glomerular filtration rate and normal urinary albumin excretion.

Eight women with insulin-dependent diabetes mellitus (IDDM) with low creatinine clearance rate (CCR) and normal urinary albumin excretion (UAE) were compared with three other groups of diabetic women: 19 with normal creatinine clearance rate (CCR) and UAE, 7 with normal CCR and microalbuminuria, and 7 with low CCR and microalbuminuria. The four groups were similar in age, duration of diabetes, HbA1, incidence of urinary tract infection, prevalence of bladder neuropathy, and urinary urea nitrogen excretion rate. The prevalence of hypertension was similar among the groups, although mean arterial pressure was higher in the low CCR and microalbuminuria group. Renal area index was lower in the low CCR and normal UAE groups than in the other groups of diabetic patients, but was not different from normal. Morphometric measures of mesangial expansion and estimates of arteriolar hyalinosis and global glomerulosclerosis were increased to a similar degree in the low CCR and normal UAE, normal CCR and microalbuminuria, and low CCR and microalbuminuria groups compared with the group without abnormalities of renal function. Therefore, it is likely that diabetic glomerulopathy is, at least in part, responsible for the loss of glomerular filtration rate seen in the low CCR and normal UAE patients. Thus, the definition of incipient nephropathy may have to be expanded beyond the concept of microalbuminuria if longitudinal study of such patients reveals an increased risk of the subsequent development of overt nephropathy. Finally, screening for diabetic kidney disease among IDDM patients should include determination of glomerular filtration rate and measurement of UAE and blood pressure, especially among women.

Adult↗
PubMed1992

Cell and matrix components of the glomerular mesangium in type I diabetes.

In a cross-sectional study, glomerular basement membrane (GBM) width, the volume fractions of the mesangium (VvMes), its cell (VvCell) and matrix (VvMatx) components, and surface density of the peripheral capillary surface (SvPGBM) were measured in renal biopsies from 187 nondiabetic living related and cadaveric donors of kidneys for transplantation and from 150 patients with insulin-dependent (type I) diabetes mellitus of 1-41 yr duration. In the diabetic patients, the matrix was the major factor in the expansion of the mesangium. However, both VvCell (0.11 +/- 0.04) and VvMatx (0.20 +/- 10) in diabetic patients exceeded the same measurements in nondiabetic subjects (0.07 +/- 0.02 for each component) (P less than 0.001 in each case). Linear regression analysis demonstrated significant correlations (P less than 0.001 for all) between GBM width, VvMes, VvCell, VvMatx, or SvPGBM and either urinary albumin excretion and creatinine clearance, with the higher correlation coefficients in all cases with albuminuria. Of the structural parameters, VvMatx correlated best with either functional measure by stepwise regression, with GBM as an added factor only with albuminuria. Therefore, although models of diabetic glomerulopathy must consider enlargement of both mesangial cells and matrix, the predominant factor in the progression of structural and functional renal disease is mesangial matrix expansion.

Adult↗
PubMed1991

Germline mutations in the Wilms' tumor suppressor gene are associated with abnormal urogenital development in Denys-Drash syndrome.

Denys-Drash syndrome is a rare human condition in which severe urogenital aberrations result in renal failure, pseudohermaphroditism, and Wilms' tumor (nephroblastoma). To investigate its possible role, we have analyzed the coding exons of the Wilms' tumor suppressor gene (WT1) for germline mutations. In ten independent cases of Denys-Drash syndrome, point mutations in the zinc finger domains of one WT1 gene copy were found. Nine of these mutations are found within exon 9 (zinc finger III); the remaining mutation is in exon 8 (zinc finger II). These mutations directly affect DNA sequence recognition. In two families analyzed, the mutations were shown to arise de novo. Wilms' tumors from three individuals and one juvenile granulosa cell tumor demonstrate reduction to homozygosity for the mutated WT1 allele. Our results provide evidence of a direct role for WT1 in Denys-Drash syndrome and thus urogenital system development.

Acute Kidney Injury↗
PubMed1991

The role of the pediatric nephrologist in the care of children with diabetes mellitus.

The pediatric nephrologist has traditionally not been involved in the care of the diabetic child since diabetic nephropathy presents in adulthood. Recent studies suggest that diabetic kidney disease develops silently during childhood. Measurement of urinary albumin excretion (UAE) allows earlier detection of patients at risk of nephropathy, often in adolescence. In addition to diabetic nephropathy, diabetic children are at risk of urinary tract infections, renal papillary necrosis, and various forms of glomerulonephritis. The role of the pediatric nephrologist in the care of the child with diabetes might include advising on the administration and interpretation of screening for UAE and the measurement and interpretation of glomerular filtration rate, and blood pressure. Children with evidence of renal dysfunction should be evaluated and treated by the pediatric nephrologist. Frequently, renal biopsy will be necessary in these patients. Future research may allow the detection of diabetic kidney disease earlier in childhood, further expanding the role of the pediatric nephrologist. In particular, early renal biopsy may eventually be used to select those patients at risk of diabetic nephropathy for specific treatment alterations.

Albuminuria↗
PubMed1991

X-chromosome inactivation in the liver of female heterozygous OTC-deficient sparse-furash mice.

X-chromosome inactivation patterns were investigated in livers of nine spfash female heterozygous ornithine transcarbamylase (OTC)-deficient mice. Quantitative morphometric analysis of cellular mosaicism was performed on sections of frozen liver reacted with purified anti-OTC antibody and prepared for immunofluorescent microscopy. Analysis of enzymatic OTC activity was performed on sections of these livers using a radiochromatographic technique. Several areas of cellular mosaicism were seen in each of the histological sections that were studied. The distribution of the volume fraction of the liver tissue cells having cells with normal OTC content among the nine mice ranged from 20 to 70% and it correlated (r = 0.8, P = 0.005) with the enzymatic activities of the respective livers. The extreme variegation of mosaic patches in the liver suggests the high probability that a single needle biopsy will be diagnostic in females heterozygous for an OTC mutation. This study also suggests that at the time of X inactivation, the number of primordial liver embryonic cells is small and the observed variegation of liver mosaicism probably results from complex migration patterns of liver cells during fetal development. This study shows that the spfash mouse is a suitable animal model for quantitative studies of X-chromosome inactivation in liver using immunohistochemical staining of OTC protein.

Animals↗
PubMed1991

Global glomerular sclerosis and glomerular arteriolar hyalinosis in insulin dependent diabetes.

We studied the lesions of global glomerular sclerosis and arteriolar hyalinosis in 43 (29 females) insulin-dependent diabetes mellitus (IDDM) patients whose creatinine clearance (CCr) was greater than or equal to 45 ml/min/1.73 m2 and whose renal biopsies had at least 20 glomeruli available for study. These patients, ages 17 to 55 years, had IDDM for 7 to 32 (20 +/- 6, means +/- SD) years. CCr ranged from 47 to 139 (91 +/- 25) ml/min/1.73 m2 and urinary albumin excretion (UAE) from 5 to 3386 (median = 127) mg/24 hrs. Eighteen patients were hypertensive. Thus, these patients represented a broad clinical range from normal renal function through overt diabetic nephropathy. The percent of glomeruli which were globally sclerosed was strongly correlated with CCr (r = -0.64, P less than 0.0001) and log UAE (r = +0.67, P less than 0.001). Hypertension was more common in patients with more than 10% sclerosed glomeruli (chi square = 9.5, P less than 0.002). Percent sclerosed glomeruli was highly significantly correlated with the index of severity of the arteriolar hyalinosis lesion (r = +0.66, P less than 0.0001) and mesangial volume fraction (r = +0.61, P less than 0.0001). We hypothesize that arteriolar hyalinosis could contribute to global glomerular sclerosis through severe compromise of glomerular blood flow. Alternately, global glomerular sclerosis may result from marked mesangial expansion and capillary occlusion. However, in this broad range of patients it appeared that global glomerular sclerosis and mesangial expansion were not infrequently independent diabetic renal lesions which could contribute separately to the ultimate development of overt diabetic nephropathy.

Adolescent↗
PubMed1991

Long-term quality of life after kidney transplantation in childhood.

Transplantation is the treatment of choice for children with end-stage renal disease. However, the long-term quality of life and socioprofessional outcome for those with successful transplants have not previously been reported. We studied these factors in patients transplanted when less than 18 years old who currently have greater than or equal to 10 years of graft function. A total of 57 questionnaires were sent out; 57 (100%) responded [24 female and 33 male patients; average (+/- SD) age at tx = 10 +/- 5 years (0.9-17.7); average f/u = 15.6 +/- 3 years (10-26); current age = 26 +/- 5 years (12-38); 26 had greater than 1 transplant]. Of the 57 respondents, 9 are less than 18 (all are in school); 48 are greater than or equal to 18 (7 in school, 37 employed, 4 unemployed); 12 are married, 1 engaged, and 2 divorced; and 9 have children. While in school, 43 (75%) had participated in sports, 37 (65%) in other extracurricular activities; 7 (12%) were A and 33 (58%) B students; 15 (26%) received awards or scholarships. For those working, the range of occupations is broad (average work week = 41 +/- 5 hr). Health-related absence from work has been nonexistent for 93%. Health is rated as good to excellent by 91% and fair by 9%. The future is regarded as hopeful or promising by 80%. Similarly, 89% are satisfied with life in general; 95% said health never or seldom interferes with family life; 95% feel health and drug side effects are of no or minor concern in sexual relationships. Only 3% feel health is a problem in maintaining a sexual relationship (41% are not sexually active). Only 4% stated that health often interferes with social life; 98% meet with friends on a regular basis; 76% are satisfied with personal relationships and 8% dissatisfied; 91% are satisfied with their ability to perform at work or school and 5% dissatisfied. Of note, 32% are dissatisfied with body appearance. Major concerns are short stature and brittle bones. Major suggestions include education/support groups to deal with teasing at school and peer problems. We conclude that transplanted children with long-term graft function have a favorable social and professional outcome. Overall, quality of life seems excellent.

Adolescent↗
PubMed1991

An overview of role of matrix components.

The glomerular filtration barrier consists of complex matrix constituents interposed between the glomerular endothelial and epithelial cells, which constitute the lining of the glomerular capillaries. The matrix components include collagen and noncollagenous molecules such as laminin and proteoglycans. This review describes herein the metabolic consequences of diabetes mellitus to which increased permeability of the filtration barrier may be attributed by altering matrix molecules.

Animals↗
PubMed1991

Hypertension and diabetic renal disease.

Diabetic nephropathy, clinically defined by overt albuminuria, hypertension and declining GFR, affects 25-35% of IDDM patients. The risk of nephropathy peaks during the second decade of IDDM and declines thereafter, suggesting that only a subset of IDDM patients is at risk for nephropathy. A role for hypertension in the progression of established renal damage in IDDM is now accepted; however the role of hypertension in the genesis of diabetic nephropathy is not yet clear. Mesangial expansion is a characteristic lesion of diabetic nephropathology and correlates with renal function. Functional studies are not indicative of underlying renal pathology except relatively late, when glomerular injury is advanced. Microalbuminuria in the 'predictive' range (greater than 30 micrograms/min) and associated with hypertension and/or declining GFR is a marker of established diabetic glomerulopathy. Only carefully designed longitudinal studies of renal morphology and function with accurate blood pressure monitoring beginning early in the course of IDDM will clarify the relationships between blood pressure and renal damage in IDDM. In NIDDM the frequent presence of non-diabetic renal lesions, of hypertension at or before the onset of diabetes, and the relative paucity of clinical-pathological correlations currently make it difficult to understand the role of hypertension in the genesis and progression of nephropathy. Again, longitudinal studies of blood pressure and renal structure and function are required in NIDDM patients. Finally, animal models of hypertension and diabetes may aid progress in these areas.

Animals↗
PubMed1991

Diabetic nephropathy: a disease causing and complicated by hypertension.

In examining the pathophysiology underlying the development of hypertension in diabetes mellitus, it is important to draw clear distinctions between Type I and Type II diabetes. In patients with Type I diabetes, with a peak onset of disease early in the second decade of life, hypertension clearly represents the sequelae to the development of substantial renal lesions, especially in the glomerulus. Thus the prevalence of hypertension in those patients without substantial glomerular lesions approximates the incidence of hypertension in the general population (approximately 4%). In patients with Type II diabetes mellitus and onset generally later in adult life, an increase in blood pressure can often be demonstrated early after or even before diagnosis of the disease (most readily demonstrated in the Pima Indians). Furthermore, clear familial tendencies towards the development of nephropathic complications of diabetes can be shown. In patients with Type I disease, the fall in glomerular filtration rate parallels the fall in glomerular capillary surface available for filtration. This reduction in the peripheral glomerular capillary surface correlates well with the expansion of the mesangium, strongly implicating the mesangial expansion in the demise in renal function. For both Type I and Type II diabetes mellitus, the increase in albuminuria may reflect an opening of large pores in the glomerular basement membrane, thereby allowing serum proteins to cross into the filtration space.

Albuminuria↗
PubMed1991

Differential expression of basement membrane collagen chains in diabetic nephropathy.

Diabetic nephropathy is characterized by progressive expansion of mesangial matrix and thickening of the glomerular basement membrane (GBM). Kidney tissues from 13 patients with insulin-dependent diabetes mellitus were studied by immunohistochemical techniques for the distribution of three recently described collagen peptides (M28+, M28 [Good-pasture antigen], and Alport antigen) and various components of classical type IV collagen [alpha 1(IV) noncollagenous (NC) globular domain, alpha 2(IV) NC, 7S, triple helix]. Recently M28 and M28+ were designated as NC monomers of alpha 3(IV) and alpha 4(IV) based on limited amino acid sequencing. During the course of the disease, the distribution of the M28 chains and the Alport peptide segregated completely from that of classical type IV collagen. In diabetic kidneys, antibodies to the M28 and Alport peptides reacted intensely with the thickened GBM but not with the mesangium. In contrast, the reactivity of antibodies to various components of classical type IV collagen was prominent within the expanded mesangial matrix with significant decrease in reactivity in the peripheral capillary wall. In hyalinized glomeruli, components of classical type IV collagen virtually disappeared, whereas the M28 and Alport peptides persisted in the collapsed GBM. These studies support the view that expansion of the mesangial matrix and thickening of the GBM involve separate and distinct collagen components. The differential expression of the M28 and Alport peptides compared with that of classical type IV collagen may be a consequence of differing sites of synthesis (classical type IV collagen from endothelial/mesangial cells and M28 and Alport chains from visceral epithelial cells), independent control mechanisms, and/or differences in degradation.

Antibodies, Monoclonal↗