Astrocytoma and Schwann cells in coculture

Glial fibrillary acidic protein (GFAP) is the principal intermediate filament protein found in mature astrocytes. Although the exact function of GFAP is poorly understood, it is presumed to stabilize the astrocyte’s cytoskeleton and help in maintaining cell shape. Previous studies from our laboratory have shown that when astrocytes were cocultured with primary Schwann cells (pSCs), astrocytes became hypertrophied and fibrous with intensely positive GFAP staining and segregated Schwann cells (SCs) into pockets. In order to understand the functional role of GFAP in this already established astrocyte-SC coculture model, we generated GFAP-negative cell lines from a GFAP-positive astrocytoma cell line and cocultured both the cell lines with pSCs. Our studies demonstrate that the GFAP-positive cell line put out processes toward the SCs, whereas the GFAP-negative cells did not form processes and the majority of the cells remained round. The most significant and interesting finding of this study, however, is the formation of elaborate processes by SCs when grown in coculture with the astrocytoma cells, unlike SCs cultured alone, which showed their typical bipolar spindle-shaped morphology. The extent of processes did not seem to be dependent on GFAP, since SCs cultured with both the cell lines formed similar processes. This coculture model may be useful in elucidating the factor(s) responsible for the formation of processes by SCs and can be further help in our understanding of the mechanism of morphological transformation of SCs.     

Herpes zoster and post-herpetic neuralgia--a clinical trial of aspirin in chloroform for anodyne

Pain associated with Herpes Zoster (HZ) and Post-herpetic Neuralgia (PHN) has been a challenging task to manage with ease. Topical aspirin dissolved in chloroform is an effective means of reducing pain due to HZ and PHN in most patients. The locus of pain origin and analgesia induced by topical aspirin is supposed to be at cutaneous free nerve ending pain receptors. The present study was conduced in fifty two patients of HZ and PHN. Pain intensity before and after the application of drug was measured with help of Sort Form McGill Pain Questionnaire (SE-MPQ). Most of the patients experienced relief of pain within 1-5 minutes after the aspirin-chloroform application. Maximum relief was achieved in about 30-40 minutes and persisted for 5-6 hrs. In the beginning 3-4 applications were required but frequency decreased gradually as the pain abated.     

Comparative evaluation of commonly used laboratory tests for post-mortem diagnosis of rabies

Animal brain samples received at WHO Collaborating Centre laboratory at National Institute of Communicable Diseases (NICD) during the years 1991-2002 were tested by Seller's stain, Fluorescent Antibody Test (FAT) and Mouse Innoculation Test (MIT) as methods of rabies diagnosis. Negri bodies on Seller's staining could be detected in 52.5% of MIT positive brains, the concordance of this test with MIT was found to be 77.8%. FAT was positive in 91.5% of MIT positive brains, though it showed concordance of 95.7% with MIT results in the total samples. 12.2% of the samples were found positive by FAT of which 1/3rd also showed the presence of Negri bodies when MIT was negative i.e. showing that the virus is present in inactivated form. Thus emphasizing the need for timely and proper collection and transportation of specimens for testing. Seller's stain and FAT give reliable diagnosis of rabies in the brain samples in majority of the cases. MIT being time-intensive test, is of academic value only in decision making as regards initiation of Post Exposure Treatment (PET), it is recommended that in cases where Seller's stain and FAT have yielded negative results the decision to initiate PET should give due consideration to the nature and circumstances of the animal bite and other epidemiological features.     

Development and Evaluation of a Tetraplex Flow Cytometric Assay for Quantitation of Serum Antibodies to Neisseria meningitidis Serogroups A, C, Y, and W-135

A rapid and simple method for the simultaneous quantitation of serum immunoglobulin G (IgG) antibodies specific for Neisseria meningitidis serogroups A, C, Y, and W-135 was developed and evaluated. Four bead sets were generated, each conjugated with one of the meningococcal capsular polysaccharides (A, C, Y, or W-135) and serologically assessed by the use of antimeningococcal international reference sera. Cross-reactivity studies demonstrated no inhibition between monoplex and multiplex assays, and the assay was linear over a 24-fold serum dilution range. Inhibition studies demonstrated that the assay is specific, with <25% heterologous inhibition occurring. The assay was also found to have low intra- and interassay variations and limits of detection ≤650 pg/ml. A comparison of the meningococcal bead assay with the standardized meningococcal enzyme-linked immunosorbent assay showed a good correlation between the IgG concentrations obtained by each assay. The tetraplex assay has the potential to be an important addition to the serologic evaluation of meningococcal capsular polysaccharide conjugate vaccines.     

Temporal variability of Cryptosporidium in the Chesapeake Bay

Although Cryptosporidium has been found worldwide in molluscan shellfish from waters contaminated with human and animal feces, little or no related environmental data have been obtained. In the present study, oysters ( Crassostrea virginica) were collected eight times over 3 years from seven sites in the Chesapeake Bay or its tributaries, with accompanying data on water temperature, salinity, rainfall, and streamflow. Oyster gill washings were examined by immunofluorescence microscopy for Cryptosporidium oocysts. Of 1,590 oysters collected, 19.6% had detectable oocysts. Of 53 collections, oocysts were detected 81% of the time. The time when the greatest percentage of oysters at most sites had detectable oocysts coincided with the time of greatest weekly and monthly rainfall, greatest streamflow into the Bay, and lowest water temperatures. In 28% of 53 collections, C. parvum genotypes 1 and 2 and C. baileyi were identified by PCR and gene sequencing. Oocyst infectivity was confirmed from 37.5% of 40 collections by initiating C. parvum genotype 2 infections in mice.     

Ascorbic acid metabolism in rats and guinea pigs after the administration of ethanol

Ascorbic acid metabolism was studied in guinea pigs and rats after the administration of ethanol and a high dose of ascorbic acid (AA). Male guinea pigs were maintained for 30 days as follows: (1) controls (1 mg AA/100 g body wt.); (2) ethanol (1 mg AA/100 g body wt. + 900 mg ethanol/100 g body wt); (3) ascorbic acid (25 mg AA/100 g body wt.); (4) ascorbic acid + ethanol (25 mg AA/100 g body wt. + 900 mg ethanol/100 g body wt.). Rats were also grouped into four groups as in the case of guinea pigs, but the dose of AA was 200 mg/100 g body weight. Rats adjusted to ethanol intoxication by enhancing the biosynthesis of ascorbate as evidenced by elevated activity of L-gulono lactone oxidase (GLO). Hence ascorbate levels were not lowered in rats after administration of alcohol. However, alcohol administration lowered tissue levels of ascorbate in guinea pigs. But the supplementation of ascorbate along with alcohol raised the tissue level of this vitamin. Guinea pigs responded to the ascorbate deficiency during alcohol administration by lowering the degradation of ascorbate, as seen by the lower activity of the degrading enzyme gulono lactone hydrolase. It is concluded that on the administration of alcohol, guinea pigs are dependent upon additional exogenous supplies of ascorbic acid, whereas rats are not.     

Lack of IgG4 antibody response to carbohydrate antigens in patients with lymphatic filariasis.

It has been suggested that humans are genetically restricted from making IgG4 antibody responses to carbohydrate antigens. To test this hypothesis we examined sera from 35 patients with bancroftian filariasis (an infection known to induce very high levels of IgG4 antibodies to the parasite and known to be associated with repeated streptococcal infections) as well as from 15 normal individuals for their IgG and IgG subclass responses to streptococcal protein [streptolysin-O (SO), deoxyribonuclease B (DB)] and carbohydrate [group A carbohydrate (GAC)] antigens. Levels of IgG antibodies to all three antigens were found to be significantly higher in the filariasis patients compared to normals (P less than 0.01), and the subclass composition of these antibodies proved heterogenous. Although responses to all three antigens included IgG1, IgG2 and IgG3 antibodies and although IgG4 responses to the proteins SO and DB were significantly higher in the filariasis patients than in normals (P less than 0.001), more importantly there were no detectable anti-GAC IgG4 antibodies in either study group. These observations, coupled with our earlier finding of the absence of IgG4 responses to phosphocholine (PC) in patients with lymphatic filariasis, suggest that even the chronic antigenic stimulation of filarial helminth infection, which leads to very prominent IgG4 responses to protein antigens, cannot overcome the genetic restriction in humans for making IgG4 antibodies to carbohydrate antigens, whether of parasite or non-parasite origin.     

Electrical conductivity of kidney stones

Electret behaviour of surgically removed kidney stones through thermally stimulated polarization and thermally stimulated depolarization has already been reported by the authors. To develop an understanding of the conduction mechanism of such samples, d.c. conductivity was studied as a function of temperature and electric field. Temperatures from 308 to 448 K and fields from 0.5 X 10(6) to 2.5 X 10(6) V/m were used on the compressed powder pellet of a kidney stone. Conductivity was found to be 6 X 10(-11) s/m to 1.0 X 10(-11) s/m in the studied temperature range. Possibility of semiconduction is shown and it is suggested that kidney stone is a partially compensated semiconductor of n-type. The field independence of conductivity is observed at higher temperatures. The slopes of current density versus field curves suggest a warm electron effect.