Glomerular basement membrane thickness in normal adults and its application to the diagnosis of thin basement membrane disease: an Indian study.

Microscopic hematuria of non-urologic origin warrants ultrastructural study of renal biopsy. Thinning and variations in the texture of glomerular basement membrane (GBM) are difficult to be recognized under light microscope; transmission electron microscope (TEM) therefore plays a vital role in identifying such changes. Ultrastructural morphometry is a valuable diagnostic aid when GBM is suspected of being abnormally thin. In an effort to determine the normal GBM thickness (GBMT) in Indian adults and to determine the cutoff value of GBMT for a diagnosis of thin basement membrane disease (TBMD), we determined GBM thickness in 25 normal adults. Postmortem biopsies of 25 normal adults (16 males and 9 females) aging between 18-58 years were included in the study. GBM thickness was determined through ultrastructural morphometry on accurately enlarged electron micrographs as harmonic mean of 50 orthogonal intercepts across the GBM in each case. Study revealed a mean GBM thickness of 321 nm with a standard deviation (SD) of 28 nm. Mean-2SD (321-56), that is 265 nm, was fixed as cutoff value of GBMT for the diagnosis of TBMD. A systematic split study of control subjects revealed thicker GBM (329+/-38 nm) in higher age group (35-60 years) as compared to GBMT (316+/-21 nm) in lower age group (18-30 years). Males in higher age group also revealed thicker GBM (males: 343+/-39 nm versus females: 300+/-12 nm). Ten patients with non-urologic hematuria and having GBMT<265 nm were diagnosed as cases of TBMD. Patients with TBMD revealed significantly attenuated GBM as compared to age and sex matched controls (214 +/- 40 nm versus 311 +/- 17 nm; p<0.0005). No overlap was observed in the distribution of GBMT in patients of TBMD and age and sex matched controls. Ultrastructural morphometry is the ultimate and appropriate method for diagnosing TBMD.

Ultrastructural morphometry using dual axes tangential scale: a technical revelation.

While performing ultrastructural morphometry, under or over estimation of ultrastructural size could be avoided by using accurate measuring devices. Biological investigators have always relied on conventional linear scale for the baseline measurement of ultrastructural size parameters on electron micrographs to project the dimensions of intracellular organelles or tissue components. Since it was not possible to measure decimal fractions of mm with linear scale, a 'dual axes tangential scale' has been designed for measuring ultrastructural image parameters on electron micrographs with an accuracy of 0.1 mm to minimize the error in finally computed size of ultrastructural component. In an exercise using 'dual axes tangential scale' and 'conventional linear scale', measurement of glomerular basement membrane thickness (GBMT) as orthogonal intercepts across the GBM revealed a 'coefficient of variation' at 4.4% with dual axes tangential scale as compared to 'coefficient of variation' at 10.9% with linear scale, expressing superiority of dual axes tangential scale over linear scale. Use of mathematical formula rather than nomogram has been preferred. However, 'slide guide, ultrastructure size calculator' could also be used for discerning ultrastructural size after measurement with dual axes tangential scale.

Unusual eosinophilic variant of chromophobe cell renal carcinoma--an ultrastructural diagnosis.

A case of eosinophilic variant of chromophobe cell renal carcinoma (EVCCRC), an uncommon variety of renal cell carcinoma, occurred in a 72 year old male. The most problematic differential diagnosis was renal oncocytoma, as the two entities share overlapping features on histology, yet differ completely in biological behavior. EVCCRC is a potentially malignant neoplasm whereas renal oncocytoma is totally benign. Staining with Hale's Colloidal Iron using modified Mowry's technique showed granular cytoplasmic positivity. The diagnosis was confirmed by ultrastructural examination of the tumor which revealed unique features of EVCCRC like presence of numerous cytoplasmic microvesicles along with mitochondria displaying tubulo-vesicular cristae. This case delineates the role of electron microscopic examination as the sole means to differentiate EVCCRC from renal oncocytomas.

HIV-I antibodies in health and disease.

Antibodies to human immune deficiency (HIV) virus were studied in 2000 individuals including cases of non-Hodgkin's lymphoma, systemic lupus erythematosus (SLE), leprosy, chronic renal failure on haemodialysis and patients attending STD clinics. A group of blood donors was also screened, ELISA kits provided by Wellcome Diagnostics were used. Results indicate that the ELISA values were far above the cut off figure in all except in a couple where the husband who had stayed in Uganda for several years, and had features of full blown AIDS died 4 months after the diagnosis. The spouse contacted AIDS within a relatively short incubation period and died within 6 months of diagnosis. The North Indian population thus appears to be free of this virus so far. This observation will be an important lead mark in the future epidemiology of HIV infection in India.