Publications (4)1.99 Total impact

  • H S Sharma · J A Duncan · C E Johanson
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    ABSTRACT: The present investigation was undertaken to find out whether whole-body hyperthermia (WBH) alters blood-cerebrospinal fluid barrier (BCSFB) permeability to exogenously-administered tracers and whether choroid plexus and ependymal cells exhibit morphological alterations in hyperthermia. Rats subjected to 4 hours of heat stress at 38 degrees C in a biological oxygen demand (BOD) incubator exhibited a profound increase in the BCSFB to Evans blue and radioiodine. Blue staining of the dorsal surface of the hippocampus and caudate nucleus and a significant increase in Evans blue and [131]Iodine in cisternal cerebrospinal fluid were seen following 4-hour heat stress compared to control. Degeneration of choroidal epithelial cells and underlying ependyma, a dilated ventricular space, and degenerative changes in the underlying neuropil were frequent. Hippocampus, caudate nucleus, thalamus, and hypothalamus exhibited profound increases in water content after 4 hours of heat stress. These observations suggest that hyperthermia induced by WBH is capable of breaking down the BCSFB and contributing to cell and tissue injury in the central nervous system.
    Acta neurochirurgica. Supplement 02/2006; 96(96):426-31. DOI:10.1007/3-211-30714-1_88
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    ABSTRACT: Evidence continues to build for the role of atrial natriuretic peptide (ANP) in reducing cerebrospinal fluid (CSF) formation rate, and thus, intracranial pressure. ANP binds to choroid plexus (CP) epithelial cells. This generates cGMP, which leads to altered ion transport and the slowing of CSF production. Binding sites for ANP in CP are plentiful and demonstrate plasticity in fluid imbalance disorders; however, specific ANP receptors in epithelial cells need confirmation. Using antibodies directed against NPR-A and NPR-B, we now demonstrate immunostaining not only in the choroidal epithelium (including cytoplasm), but also in the ependyma and some endothelial cells of cerebral microvessels in adult rats (Sprague-Dawley). The choroidal and ependymal cells stained almost universally, thus substantiating the initial autoradiographic binding studies with 125I-ANP. Because ANP titers in human CSF have previously been shown to increase proportionally to increments in ICP, we propose a compensatory ANP modulation of CP function to down-regulate ICP in hydrocephalus. Further evidence for this notion comes from the current finding of increased frequency of "dark" epithelial cells in CP of hydrocephalic (HTx) rats, which fits our earlier observation that the "dark" choroidal cells, associated with states of reduced CSF formation, are increased by elevated ANP in CSF. Altogether, ANP neuroendocrine-like regulation at CSF transport interfaces and blood-brain barrier impacts brain fluid homeostasis.
    Acta neurochirurgica. Supplement 02/2006; 96(96):451-6. DOI:10.1007/3-211-30714-1-92
  • European Journal of Pediatric Surgery 01/2004; 13 Suppl 1:S40-2. · 0.99 Impact Factor
  • European Journal of Pediatric Surgery 01/2003; 12 Suppl 1:S47-9. · 0.99 Impact Factor