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Biomedical subjects

S M Mauer

Publications and source records attributed to S M Mauer.

At least 109 records · Page 6Linked to original sources
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↗
PubMed1986

Glomerular filtration surface in type I diabetes mellitus.

Previously we have shown that relative glomerular mesangial expansion was an important correlate of renal dysfunction in diabetes. To extend the understanding of structural functional relationships, 37 patients with type I diabetes mellitus for 5 to 33 years were studied with multiple creatinine clearance (Ccr), urinary albumin excretion, and blood pressure measurements, and percutaneous renal biopsies. Glomerular volume and percent sclerosed glomeruli were determined; quantitative stereology was performed to determine relative glomerular structural parameters. Per glomerulus we calculated mesangial volume and capillary filtration surface and per patient we estimated capillary filtration surface. Capillary filtration surface per glomerulus or per patient were highly predictive of Ccr (r = +0.78, r = +0.79, P less than 0.001). There was a significant but weak relationship between Ccr and mesangial volume. However, mesangial volume and glomerular volume together were highly predictive of both Ccr and filtration surface. Mesangial volume was increased and filtration surface decreased in the hypertensive patients and the patients with urinary albumin excretion less than 250 mg/24 hr. Thus, it appears that mesangial expansion within a relatively large glomerulus has less influence on filtration than does a similar increase in mesangial volume within a smaller glomerulus. There is a striking relationship between glomerular filtration rate and filtration surface in diabetes throughout the range from hyperfiltration to significant hypofiltration.

Adolescent↗
PubMed1986

The outcome of 304 primary renal transplants in children (1968-1985).

Of 304 children who received primary renal transplants at the University of Minnesota between January 1, 1968, and December 31, 1985, 48 (16%) were under the age of 24 months, 60 (20%) were 2-5 years old, and 196 (64%) were 6-17 years old at transplantation. Currently, 254 (84%) are alive at 2 months to 18 years following their first transplants, 77% with functioning grafts (188 first, 45 retransplants) and 7% on dialysis. Overall, patient and graft survival were not significantly different from the primary graft outcome of nondiabetic adults. The actuarial primary graft function rates at 1, 5, and 10 years were 100, 100, and 90% in 16 HLA-identical sibling kidneys; 84, 64, and 52% in 210 mismatched related kidneys; and 72, 54, and 47% in 78 cadaver kidneys (p less than 0.002). The 1-year patient survival and primary graft function rates in 44 mismatched related recipients under the age of 24 months were 92 and 88%. The use of deliberate, pretransplant random blood transfusion since 1979 has been associated with a decreased rejection rate. Primary graft function of mismatched related kidneys in children receiving standard immunosuppression has significantly improved from 78% at 1 year in the pretransfusion era to 91% (p less than 0.01) in the transfusion era. The overall primary cadaver graft function rate, however, did not improve in the transfusion era. Whether cyclosporine use will improve the cadaver renal allograft function in very young recipients remains to be established. However, with the use of related donors, even very young children can be transplanted safely and with excellent results.

Adolescent↗
PubMed1986

Relationship of muscle capillary basement membrane to renal structure and function in diabetes mellitus.

Muscle capillary basement membrane (MCBM) thickening has been considered to reflect microvascular changes in other tissues in diabetes mellitus. To explore the relationships between MCBM width and nephropathy, 27 patients aged 22-55 yr with type I diabetes for 14-33 yr were studied with creatinine clearances, urinary albumin excretion rates, multiple blood pressure measurements, glycosylated hemoglobin measurements, and renal and quadriceps muscle biopsies that were evaluated using standard stereologic techniques. MCBM width did not correlate with age, duration of diabetes, creatinine clearance, urinary albumin excretion, or fractional volume of the glomerular mesangium. MCBM width did correlate, although weakly, with glomerular basement membrane width (r = 0.47) and glycosylated hemoglobin (r = 0.44). There was no difference in MCBM width between patients with and without clinical nephropathy. Patients with normal fractional volume of mesangium exhibited a full range of MCBM width. Thus, while MCBM width may reflect glycemic control and glomerular basement membrane thickening, it does not relate to the functional or structural renal changes associated with progressive diabetic nephropathy.

Adult↗
PubMed1985

Studies of kidney and muscle biopsy specimens from identical twins discordant for type I diabetes mellitus.

To distinguish metabolic from genetic factors in the development of microangiopathy in diabetes, we evaluated biopsy specimens of kidney and quadriceps muscle from seven pairs of identical twins who were discordant for Type I (insulin-dependent) diabetes mellitus. Two of the diabetic patients had clinical diabetic nephropathy, including hypertension, marked albuminuria, and a substantially reduced creatinine clearance; the other five had normal renal function and only minor clinical indications of complications. All the twins of the diabetic patients had normal glomerular basement membrane widths and normal fractional volumes of the glomerular mesangium. Values for glomerular basement membrane width, tubular basement membrane width, and mesangial volume in each diabetic twin exceeded the values in the respective sibling (P less than or equal to 0.0035), even if the value in the diabetic twin lay within established normal ranges. Values for muscle capillary basement membrane width in the diabetic twins did not differ from those in their siblings (P = 0.5). Our observations suggest that the metabolic abnormalities of diabetes are necessary, if not sufficient, for the development of glomerular abnormalities. We also conclude that in diabetic patients, alterations in muscle capillary basement membrane width do not necessarily accompany pathologic lesions in the kidney.

Adult↗
PubMed1985

A comparison of kidney disease in type I and type II diabetes.

Diabetes is the most important cause of ESRD in the Western world. Type I and II diabetes appear to contribute importantly to ESRD although, obviously, the prevalence of ESRD is higher in Type I. Microalbuminuria may predict later development of overt clinical nephropathy in both Type I and Type II patients. In both diabetes subtypes current evidence favours the dysmetabolism of diabetes as causative. There are clinical observations in Type I and renal morphologic evidence in Type II indicating that risk of nephropathy is, in part, related to the magnitude of hyperglycemia. Institution of strict glycemic control fails to reverse established clinical nephropathy in Type I diabetes. Efforts to determine if precise regulation of blood sugar can prevent nephropathy in patients with Type I and Type II diabetes are currently incomplete.

Blood Glucose↗
PubMed1985

Relationship of renal size to nephropathy in type 1 (insulin-dependent) diabetes.

Thirty-five patients with Type 1 (insulin-dependent) diabetes mellitus and 90 normal subjects had renal size (renal area index) determined by X-ray and also had examination of renal biopsies by light and electron microscopy. Renal area index of 206 +/- 32 cm2/1.73 m2 (mean +/- SD) in the Type 1 diabetic patients exceeded that in the normal subjects (180 +/- 25 cm2/1.73 m2, p less than 0.001). In the diabetic patients, the renal area index correlated with creatinine clearance (r = +0.43, p less than 0.05), but did not correlate with urinary albumin excretion, or the electron microscopic measurements of percentage total mesangium and glomerular basement membrane width. In diabetic patients with clinical nephropathy or severe glomerulopathy on biopsy, the kidneys may remain large. Thus, renal size does not indicate the severity of diabetic renal lesions on biopsy.

Adolescent↗
PubMed1985

Urinary albumin excretion in renal transplant donors.

Twenty-four hour urinary albumin excretion was measured using sensitive methods in 129 renal transplant donors 1 to 22 years (mean 7.3 years) after kidney donation. The 24 hour urinary albumin excretion values for the donor group was 6 +/- 9.9 mg (mean +/- standard deviation) (range of 0.1 to 65.2 mg) and was 7.7 +/- 4.5 mg for the control group. Five donors (3.9 percent) had 24 hour urinary albumin excretion levels of 25.5 to 65.2 mg 6 to 13 years after donation, values that were greater than a single value from any member of the control group. Elevated diastolic blood pressure (90 mm Hg or greater) was present in these five donors, and in three, labile or established hypertension was present at the time of donation. It is likely that more careful screening of potential donors with labile or fixed hypertension would further reduce the incidence of microalbuminuria in the renal transplant donor. We conclude that urinary albumin excretion values are within the normal range in most renal transplant donors studied several years after renal donation.

Adolescent↗