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Biomedical subjects

J Balakrishnan

Publications and source records attributed to J Balakrishnan.

12 recordsLinked to original sources
PubMed2000

Spatial curvature effects on molecular transport by diffusion.

For a substance diffusing on a curved surface, we obtain an explicit relation valid for very small values of the time, between the local concentration, the diffusion coefficient, the intrinsic spatial curvature, and the time. We recover the known solution of Fick's law of diffusion in the flat space limit. In the biological context, this result would be useful in understanding the variations in the diffusion rates of integral proteins and other molecules on membranes.

Biological Transport↗
PubMed1997

A new mutation, 3905insT, accounts for 4.8% of 1173 CF chromosomes in Switzerland and causes a severe phenotype.

We have analysed 1173 cystic fibrosis (CF) chromosomes from Switzerland for eight mutations in the CF transmembrane conductance regulator (CFTR) gene. This permitted the identification of 88.5% of all mutations present. A novel insertion mutation in exon 20 of the CFTR gene, 3905insT, was discovered. This mutation accounted for 4.8% of CFTR gene mutations in Switzerland and has since been identified in other populations of probable Swiss descent. It is associated with a highly variable clinical phenotype but always with pancreatic insufficiency. Haplotype analysis with three intragenic microsatellites in the CFTR gene showed that the mutation is associated with a haplotype rarely identified on other CFTR alleles and, therefore, that the frequency of the mutation in Switzerland is explained by a founder effect of a relatively recent mutation event.

Cystic Fibrosis↗
PubMed1990

Acquired immunodeficiency syndrome: correlation of radiologic and pathologic findings in the brain.

The appearance on magnetic resonance (MR) and computed tomographic (CT) images of specific central nervous system disorders associated with acquired immunodeficiency syndrome in 12 cases was correlated with autopsy findings. There were three cases of human immunodeficiency virus (HIV) encephalopathy; three, primary lymphoma; three, toxoplasmosis; one, cryptococcosis; one, cytomegalovirus infection; and one, progressive multifocal leukoencephalopathy. MR imaging demonstrated the various cranial lesions more clearly than did CT. On the basis of MR imaging characteristics, HIV encephalopathy could be distinguished from other lesions, particularly progressive multifocal leukoencephalopathy. Basal ganglia were the most common sites of involvement in opportunistic infections and primary lymphoma. Reliable distinguishing features among lesions of the basal ganglia were not found, except for cryptococcal lesions, which had a unique appearance.

AIDS Dementia Complex↗
PubMed1989

Neuropathological changes in early HIV-1 dementia.

Early pathological abnormalities in human immunodeficiency virus (HIV-1)-related dementia have not been well documented. We report a homosexual man with fatigue and intermittent diarrhea in whom early HIV-1-related dementia was demonstrated during neurological screening in the Multicenter AIDS Cohort Study. Within 4 months he died of massive epistaxis, and the brain revealed astrocytosis of white matter and mild pallor of myelin staining in the absence of inflammation, multinucleated giant cells, and brain atrophy.

AIDS Dementia Complex↗
PubMedDate not supplied

Hyperintense thrombus on GRASS MR images: potential pitfall in flow evaluation.

Gradient-recalled acquisition in the steady state (GRASS) MR images, obtained in four patients with angiographic evidence of successful occlusion of cerebral arteriovenous malformations, demonstrated hyperintense signal intraluminally. Although this was initially mistaken as evidence of persistent blood flow in the arteriovenous malformation, the short TR/TE spin-echo images showed hyperintense signal rather than flow void, thereby indicating the presence of subacute thrombus. GRASS images alone should not be used to determine the success of embolotherapy of cerebral arteriovenous malformations or to determine aneurysm patency, since the hyperintense signal is a potential pitfall that may mislead the radiologist in the absence of corroborative images, particularly the short TR/TE spin-echo sequences.

Adolescent↗
PubMedDate not supplied

Pulmonary infarction: CT appearance with pathologic correlation.

The CT appearance of 12 proven pulmonary infarcts in 10 patients was analyzed and correlated with pathologic appearance. The diagnosis of pulmonary infarction was clinically suspected in only 2 of the 10 patients. A pleural based parenchymal density with convex, bulging borders and linear strands directed from the apex of the density toward the hilum was noted in each case (n = 12). Other features were a truncated apex (n = 10), a broad pleural base (n = 10), and scattered areas of reduced attenuation within the lesions (n = 7). This distinctive complex of findings on CT should raise a strong suspicion of pulmonary infarction.

Adult↗