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Biomedical subjects

E N Ellis

Publications and source records attributed to E N Ellis.

35 records · Page 2Linked to original sources

Concepts of fluid therapy in diabetic ketoacidosis and hyperosmolar hyperglycemic nonketotic coma.

Despite many advances in the overall treatment of type I diabetes mellitus during the last few years, no major advance has been made in decreasing the mortality rate of diabetic ketoacidosis or hyperosmolar hyperglycemic nonketotic coma. A major concern in both of these disease states is the development of cerebral edema during treatment. The guiding principles of therapy in both disease states are rehydration, electrolyte replacement, insulin therapy, and treatment of any underlying illnesses. If the patient is hypotensive, therapy begins with colloid or normal saline administration to support blood pressure. Fluid and electrolyte deficits should be calculated and replaced during 48 hours. Low-dose insulin therapy is employed for treatment of hyperglycemia. Neurologic function should be carefully monitored and mannitol administered if a change in neurologic function occurs.

Child↗

Glomerular lesions and urinary albumin excretion in type I diabetes without overt proteinuria.

Since several studies have suggested that a slight increase in urinary albumin excretion (microalbuminuria) is predictive of nephropathy in patients with diabetes mellitus, we studied the relation of albumin excretion to renal structure in patients with insulin-dependent (Type I) diabetes. Renal biopsy specimens were evaluated with light- and electron-microscopical morphometric techniques in 48 patients who had had diabetes for 5 to 40 years and who excreted less than 200 mg of urinary albumin per 24 hours. Patients in Group I (n = 26) had normal urinary albumin excretion, creatinine clearance, and blood pressure; those in Group II (n = 10) had increased urinary albumin excretion but normal creatinine clearance and blood pressure; those in Group III (n = 12) had increased urinary albumin excretion and hypertension, decreased creatinine clearance, or both. Glomerular structure varied similarly, ranging from normal to abnormal in Groups I and II, but was consistently abnormal in Group III. The thickness of the glomerular basement membrane, the fractional volume of the mesangium, and the mesangial volume per glomerulus in Group III exceeded the corresponding values in the other groups significantly. Thus, microalbuminuria, when present with hypertension, decreased creatinine clearance, or both, indicates established abnormalities of glomerular structure. Normal albumin excretion, or microalbuminuria without these other functional abnormalities, does not accurately predict the severity of the underlying glomerular lesions in patients with Type I diabetes.

Adolescent↗

Glomerular capillary morphology in normal humans.

Knowledge of quantitative glomerular structure in normal man is limited. At the time of renal transplantation, 28 living-related normal kidney donors had renal biopsies performed. Tissue was processed for light and electron microscopy using standard techniques. Standard stereologic techniques were used to determine mean glomerular volume, capillary length density, fractional volumes of mesangium and capillary lumen, surface densities of the peripheral capillary, mesangial-epithelium interface, and the lumenal-mesangial interface. Volume of total mesangium/glomerulus, capillary lumenal volume/glomerulus, peripheral capillary filtration surface/glomerulus, capillary mesangial-epithelial surface/glomerulus, capillary lumenal-mesangial surface/glomerulus, capillary length/glomerulus, and average capillary diameter were calculated. There were no significant differences between males and females in any structural parameter. There were no significant correlations between age or body surface area and any structural parameter. In comparison with these normal values, previously reported diabetic patients with clinical nephropathy demonstrate markedly expanded mesangial volume/glomerulus and a diminished filtration surface/glomerulus. The availability of these normal values will allow comparison with functional data in normal humans and greater understanding of human glomerular disease.

Adult↗

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↗

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↗

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↗

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↗

Urinary N-acetyl-beta-D-glucosaminidase in streptozotocin-induced diabetic rats.

Excretion of urinary N-acetyl-beta-D-glucosaminidase has been found to be elevated in diabetic humans and rats. This urinary glycosidase may reflect blood sugar control over time, since it has been significantly and positively correlated with hemoglobin A1 in children with insulin-dependent diabetes. Other studies have suggested that urinary NAG may predict diabetic nephropathy. In order to more carefully define the relationship between urinary NAG excretion and blood and urine sugars, hemoglobin A1, and microalbuminuria, 48 rats were made diabetic by the use of streptozotocin. All rats were uninephrectomized at 3 weeks. Of these, 23 were treated with daily insulin injections, 25 were untreated, and both groups were compared to 13 control, nondiabetic rats. Urine volume, glucose, albumin, and blood sugar were all significantly (P less than 0.05) elevated in the untreated rats compared to the treated and control groups. Urinary NAG:UCr was significantly (P less than 0.01) elevated in the untreated group with lower but still elevated levels (P less than 0.05) in the treated rats. To further define the time course of the increase in UNAG:UCr 12 rats were followed serially at 12-hr intervals for 92 hr after streptozotocin. Urinary NAG increased significantly (P less than 0.05) at 12 hr after streptozotocin injection and reached a plateau at 36 hr while hemoglobin A1 did not rise until 2 weeks after onset of hyperglycemia. Urinary NAG increases more rapidly than hemoglobin A1 after onset of hyperglycemia and glycosuria.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylglucosaminidase↗

Structural-functional relationships in diabetic nephropathy.

Renal biopsies in 45 patients with insulin-dependent diabetes mellitus (IDDM) were examined by semiquantitative light microscopy and quantitative electron microscopic stereologic morphometry. In these 14 males and 31 females, aged 13-52 yr, who had had IDDM for 2.5-29 yr there was no strong relationship between either glomerular basement membrane (GBM) thickness or mesangial expansion and duration of IDDM. There was only a weak relationship between the thickness of the GBM and expansion of the mesangium. Thus, GBM thickening and mesangial expansion in IDDM occur at rates that often differ from one another and that vary greatly among patients. The clinical manifestations of diabetic nephropathy, albuminuria, hypertension, and decreased glomerular filtration rate related poorly or not at all to GBM thickening. In contrast, all light and electron microscopic measures of mesangial expansion were strongly related to the clinical manifestations of diabetic nephropathy, although in the absence of these clinical findings, it was not possible to predict the severity of any of the diabetic glomerular lesions. Mesangial expansion had strong inverse correlations with capillary filtering surface area density. It is hypothesized that mesangial expansion could lead to glomerular functional deterioration in IDDM by restricting the glomerular capillary vasculature and its filtering surface. However, capillary closure, glomerular sclerosis, and interstitial fibrosis could also contribute to the clinical manifestations of this disorder.

Adolescent↗

Renal function in children undergoing cardiac operations.

Because we sometimes observed large amounts of uric acid crystals in the urine of infants and children after open-heart operations and since renal insufficiency from any cause can be a serious complication of cardiac procedures, 8 acyanotic and 5 cyanotic children were studied prospectively by comparing several preoperative and postoperative measures of renal function. There were no significant differences between the acyanotic and cyanotic groups in terms of age, time on cardiopulmonary bypass, or other preoperative variables. Postoperatively, children in both groups had a wide range of free water clearances (CH2O), with some values in the range reported to be diagnostic of renal insufficiency in adults. Since none of these children had renal insufficiency by other criteria, CH2O may not be as reliable an indicator of renal insufficiency in children. The major difference between the cyanotic and acyanotic groups was seen in postoperative serum uric acid levels (SUA); the mean SUA levels in the acyanotic and cyanotic groups were 5.3 +/- 0.5 mg/dl (+/- standard error of the mean) and 10.4 +/- 1.7 mg/dl (range, 8.0 to 15.5 mg/dl), respectively. Since the hyperuricemia in the cyanotic children could not be related to increased exogenous administration or decreased renal excretion, it is probably caused by increased endogenous production and may be related to the resolution of the cyanotic state.

Acute Kidney Injury↗

Use of urinary indexes in renal failure in the newborn.

Causes of renal failure and urinary indexes were recorded in 45 neonates with oliguria and uremia. Twenty (44%) had ischemic renal damage; nine of these infants recovered and 11 died. Eight infants (18%) had various other causes of renal insufficiency. Determination of serum BUN or creatinine concentrations did not differentiate between these groups. Fractional excretion of sodium (FENa) and renal failure index (RFI) determined on serum and first-voided urine samples were statistically different between the neonates with prerenal uremia and the neonates with ischemic renal damage, although there was overlap between the groups. A neonate with an FENa less than 2.5% and an RFI less than 2.5 is said to have prerenal uremia. An FENa greater than 2.5% or an RFI greater than 2.5 in a neonate suggests ischemic renal disease; however, some neonates with prerenal uremia may have values in this range.

Acute Kidney Injury↗

Idiopathic membranous nephropathy in children.

To determine the prognosis in children with membranous nephropathy, we reviewed the clinicopathologic features and outcome of 22 patients, 11 male and 11 female, age 11 months to 19.9 years (mean 12.0 years). Patients had biopsies within six months of onset of symptoms and were divided into two groups according to the biopsy findings: group 1 (Stages I and II) and group 2 (Stages III and IV). Follow-up time was identical in both groups (mean 4.8 years). The nephrotic syndrome was present in 13 of 16 patients in group 1 and in all six patients in group 2. In group 1, eight of the 16 patients had repeat biopsies one to 11 years (mean three years) after onset. Of these, two progressed to Stages III and IV, whereas progression to renal insufficiency occurred in only one. In group 2, two of the six patients had repeat biopsies two years after onset and remained in the same group; progression to renal insufficiency occurred in five of the six patients. The difference in progression to renal insufficiency between the two groups is significant (P = 0.001). The stage of glomerular lesion at the time of onset seems to be a factor in predicting the prognosis of membranous nephropathy in pediatric patients.

Adolescent↗

Effects of hemodialysis and dimercaprol in acute dichromate poisoning.

A 22-month-old infant died after ingesting sodium dichromate his father had brought from work. Treatment included folic acid and dimercaprol administration, hemodialysis, and exchange transfusion. To evaluate this treatment, four dogs were hemodialyzed after receiving intravenous sodium dichromate: their dialyzer chromate clearance was similar to their renal chromate clearance and their dialyzer chromate clearance was not significantly different before or after dimercaprol administration. This and other cases in the literature indicate that although chromate poisoning is often fatal, supportive care, forced diuresis, and chelating agents may be helpful. Hemodialysis may be required if renal failure occurs. Awareness of toxicity and prevention remain the most important approaches.

Acute Disease↗

Focal segmental glomerulosclerosis, crescent, and rapidly progressive renal failure.

The usual clinical course of focal segmental glomerulosclerosis is marked by progressive decrease in renal functional and sclerosis on biopsy over a period of months to years. We report a variant exemplified by 2 children who developed chronic renal failure within 12 weeks of the onset of nephrotic syndrome; repeat renal biopsies demonstrated extensive extracapillary glomerular proliferation and crescent formation. Both were males, less than 5 years of age, presenting with nephrotic syndrome resistant to steroid therapy and normal renal function. Renal biopsies done after 8 weeks of therapy, demonstrated findings compatible with focal segmental glomerulosclerosis. Within 12 weeks of onset of nephrotic syndrome, both patients experienced a decrease in renal function requiring dialysis. Repeat renal biopsies revealed extensive extracapillary glomerular proliferation with crescent formation. These patients represent a variant of focal segmental glomerulosclerosis characterized by rapid progression to renal failure with extensive extracapillary glomerular proliferation and crescent formation.

Biopsy↗

Effects of estrogen administration on the lipoproteins and apoproteins of the chicken.

The plasma lipoproteins of estrogen-treated and untreated sexually immature hens have been compared with respect to their concentration in plasma, protein and lipid composition, particle size, and and apoprotein composition. Administration of diethylstilbestrol resulted in a 400-fold rise in the concentration of very low density lipoprotein (VLDL), a 70-fold rise in low density lipoprotein (LDL), and a marked reduction in high density lipoprotein (HDL) protein. It also resulted in the production of LDL and HDL which were enriched in triacylglycerol, while the proportion of cholesterol in all three lipoprotein fractions decreased. In contrast to the lipoproteins from untreated birds, lipoproteins of density less than 1.06 g/ml from estrogen-treated birds were not clearly separable into discrete VLDL and LDL fractions, but appeared to be a single ultracentrifugal class. The apoprotein composition of VLDL and LDL from untreated birds differed from each other; however, the apoprotein patterns of VLDL and LDL from estrogen-treated birds were indistinguishable: both contained a large amount of low molecular weight protein in addition to the high molecular weight component that predominates in the untreated state. The apoprotein composition of HDL was also markedly altered by estrogen administration: the 28,000 mol. wt. protein (apo A-I) decreased in amount from 65% to less than 5% of the total, while a low molecular weight (Mr = 14,000) protein and as yet poorly defined high molecular weight components became predominant. These observations indicate that the hyperlipidemia induced by estrogen administration is accompanied by marked alterations, both qualitative and quantitative, in the plasma lipoproteins.

Animals↗

Urinary excretion of N-acetyl-beta-D-glucosaminidase in children with type I diabetes mellitus.

N-acetyl-beta-D-glucosaminidase (NAG), a lysosomal enzyme, has been shown to be increased in the urine of patients with various glomerulonephritides, tubulointerestitial diseases, renal allograft rejection, toxic renal injury, and diabetes mellitus. Although it has been suggested that urinary NAG may reflect blood glucose control, no studies have correlated this with other measures of metabolic control. Thirty-four children from a diabetic summer camp were found to have urinary NAG to creatinine ratios significantly above those of normal controls of similar age (5.22 +/- 1.19 versus 1.51 +/- 0.17 U). Urinary NAG was found to positively correlate with an arbitrary control index (r = 0.82; P less than 0.05) and in seven patients with hemoglobin A1c (r = 0.70; P less than 0.001). In a closely followed group of 40 clinic patients, urinary NAG to creatinine ratio was again found to be significantly increased over normal controls (7.55 +/- 0.70 versus 1.51 +/- 0.17 U; P less than 0.05). Again, urinary NAG was positively correlated with HbA1c (r = 0.62; P less than 0.001) and urinary albumin to creatinine ratio (r = 0.47; P less than 0.01). In neither group was there a correlation with UNAG:UCr and duration of disease. Thus, these data suggest that urinary NAG to creatinine ratio appears to be a reflection of blood sugar control.

Acetylglucosaminidase↗