Purified viral neuraminidase vaccine to control influenza.

The control of influenza by immunoprophylaxis is difficult because of the antigenic mutability of the influenza virus and the unpredictability of its epidemiologic behaviour. The inactivated whole-virus vaccine currently used is not ideal. Vaccination with pure neuraminidase is suggested. The induced antineuraminidase antibody will restrict viral invasion. Mild illness may or may not occur. On subsequent exposure to influenza virus the individual will produce antihemagglutinin and antineuraminidase antibodies and will be resistant to both infection and illness. Since antigenic changes are less frequent in the viral neuraminidase than in the viral hemagglutinin, the vaccine would be usable for longer periods than the presently used inactivated whole-virus vaccine.     

Pentose phosphate pathway in rat colonic epithelium

The colonic cells of the large intestine are one of the most proliferative tissues of the animal body. The pentose pathway has an essential role in cell division and growth being the only pathway forming ribose 5-P necessary for all nucleotide and nucleic acid sunthesis. The pentose pathway may also provide reducing potential as NADPH for biosynthesis and C-3- C-8 glycolyl compounds. The maximum catalytic capacities of the reactions of the non-oxidative pentose pathway for the conversion of ribose 5-P to hexose and triose phosphates by the proximal and distal colon under feeding and starvation regimes are among the highest in the animal body. The qualitative presence of the oxidative pentose pathway was assessed by measurement of the C-1/C-6 ratio value of 1.67-1.82. Enzymes of the F-type and L-type pentose pathways are present in colonocytes and their maximum catalytic activities in colonocyte cytosol are reported. The contribution of the F-type pentose cycle to the total glucose metabolism of colonocytes, measured by the specific yield method, is negligibly low (approximately 1.5%). Colonic epithelial cells use glucose at a high rate (7.1 +/- 0.33 mumol min-1g-1 dry wt) and 79% of the glucose is converted to lactate. Arabinose 5-P has an intermediary role in the formation of keto pentose, sedoheptulose and hexose phosphates from ribose 5-P by colonocyte cytosol. The intermediary and reaction products of [1-13C] ribose 5-P dissimilation by colonocytes is investigated by 13C NMR spectroscopy. The 13C positional isotope distributions show labelling of C-1 and C-3 of hexose 6-phosphates consistent with either the theoretical predictions of the F-type pentose pathway or of the activities of exchange reactions catalysed by transketolase and/or transaldolase. Measurements of exchange reactions showed that the C-1/C-3 labelling of these compounds is mostly, if not wholly, attributable to exchange catalysis by these group transferring enzymes. The results suggest that the F-type PC has little role in the glucose metabolism of colonocytes and pentose phosphate formation may thus occur by a contribution (approx 20% of the total glucose metabolism) by the alternate L-type pathway.     

Incidence of squatting facets on the talus of Indians (Agra region).

230 adult Indian tali (from Agra region) were studied for the incidence of squatting facets. Extension of medial articular facet was observed in all the cases. Medial extension of trochlea was observed in 37% of cases; lateral extension of trochlea in 71.6% of cases, lateral squatting facets in 43.5% of cases and medial squatting in 8.6% of cases. The present data are compared with that of other workers.     

A photoaffinity label for the thromboxane A2/prostaglandin H2 receptor in human blood platelets

A photoactive iodoarylazide derivative (I-APA-PhN3) of the competitive thromboxane A2/prostaglandin H2 (TXA2/PGH2) antagonist 13-azaprostanoic acid is evaluated. Upon photoactivation, the compound was found to inhibit specifically and irreversibly human platelet aggregation induced by the TXA2/PGH2 mimetic U46619. In receptor-binding studies using [3H]U46619, I-APA-PhN3 exhibited an IC50 of 300 nM for inhibition of U46619 binding. Photoactivation of I-APA-PhN3 resulted in an irreversible 58% reduction in specific binding of U46619. This compound and its corresponding ratio-iodinated form will prove to be useful tools for the isolation and purification of the TXA2/PGH2-binding protein in human platelets.     

Biodecolourization of azo and triphenylmethane dyes by <Emphasis Type="Italic">Dichomitus squalens</Emphasis> and <Emphasis Type="Italic">Phlebia</Emphasis> spp

Nine white-rot fungal strains were screened for biodecolourization of brilliant green, cresol red, crystal violet, congo red and orange II. Dichomitus squalens, Phlebia fascicularia and P. floridensis decolourized all of the dyes on solid agar medium and possessed better decolourization ability than Phanerochaete chrysosporium when tested in nitrogen-limited broth medium. Journal of Industrial Microbiology & Biotechnology (2002) 28, 201–203 DOI: 10.1038/sj/jim/7000222 Received 12 July 2001/ Accepted in revised form 22 October 2001     

Collagen phagocytosis is regulated by the guanine nucleotide exchange factor Vav2

Collagen phagocytosis is a crucial alpha2beta1-integrin-dependent process that mediates extracellular matrix remodeling by fibroblasts. We showed previously that after initial contact with collagen, activated Rac1 accelerates collagen phagocytosis but the Rac guanine nucleotide exchange factors (GEFs) that regulate Rac are not defined. We examined here the GEFs that regulate collagen phagocytosis in mouse fibroblasts. Collagen binding enhanced Rac1 activity (5-20 min) but not Cdc42 or RhoA activity. Analysis of collagen bead-associated proteins showed enrichment with Vav2, which correlated temporally with increased Rac1 activity. Knockdown of Vav2 prevented Rac activation, recruitment of Rac1 to collagen bead binding sites, and collagen bead binding, but knockdown of Sos-1 or beta-Pix had no effect on Rac activation or collagen binding. Vav2 was associated with the nucleotide-free Rac1 mutant (G15ARac1) after collagen binding. Collagen bead binding promoted phosphorylation of Vav2, which temporally correlated with Rac1 activation and which required Src kinase activity. Blockage of Src activity prevented collagen bead-induced Rac activation and collagen bead binding. Collectively these data indicate that Vav2 regulates the Rac1 activity associated with the binding step of collagen phagocytosis.     

Spatial distribution of lead in enamel and coronal dentine of wistar rats

Lead is one of the most hazardous environmental toxins known. The assessment of lead in dental hard tissues is important in the understanding of its toxic effects on oral tissues and in estimating exposure and body burden in individuals exposed to lead from the environment. However, current information on the uptake and distribution of lead in enamel and dentine is limited. The aim of this project was to study, at high resolution, the spatial distribution of lead in enamel and coronal dentine using an experimental rat model. A dose of 40 mg/L of lead nitrate was administered to pregnant female rats during the periods of gestation and lactation through drinking water. First mandibular molar teeth were removed from their 15-d-old pups and the distribution of lead was studied using a nuclear microprobe (NMP). The distribution of lead in enamel and coronal dentine showed four distinct zones with significantly different mean lead concentrations (p<0.05). High levels of lead were observed in the superficial regions of enamel and in the dentine directly adjacent to the pulp. Additionally, the results confirmed that the NMP is capable of mapping the distribution of lead in teeth at micron resolutions with a detection limit of approx 1 microg/g.