Global analysis of neutrophil gene expression

A widespread, but incorrect, view of the neutrophil portrays it as a short-lived, terminally differentiated cell that has a highly condensed nucleus and hence is unable to induce gene expression. However, these cells express mRNA encoding phagocytic receptors, modulate RNA synthesis in response to lectin stimulation or glucocorticoid treatment, and upregulate genes involved in phagocytic function, such as respiratory burst activity and cytokine secretion. Most studies of neutrophil gene expression have examined cytokine stimulation and have focused on a few specific genes of known interest, rather than the global genetic repertoire of the cell. In part stimulated by the availability of gene and expressed sequence tag databases, several approaches have been developed to assess the levels of all mRNA species found in single RNA preparations. We have analyzed the regulation of gene expression in neutrophils using a gel-based method that displays 3' end fragments of cDNA generated by restriction enzymes. Our data indicate that neutrophils are capable of extensive, rapid, and complex changes in gene expression, involving at least several percent of all mRNAs present in the cell. The number and magnitude of mRNA responses are comparable to those measured on activation of normal T cells. The data also indicate that activated neutrophils are a source of newly synthesized, physiologically significant, intercellular signaling molecules.     

Human fatty acid synthase: structure and substrate selectivity of the thioesterase domain

Human fatty acid synthase is a large homodimeric multifunctional enzyme that synthesizes palmitic acid. The unique carboxyl terminal thioesterase domain of fatty acid synthase hydrolyzes the growing fatty acid chain and plays a critical role in regulating the chain length of fatty acid released. Also, the up-regulation of human fatty acid synthase in a variety of cancer makes the thioesterase a candidate target for therapeutic treatment. The 2.6-A resolution structure of human fatty acid synthase thioesterase domain reported here is comprised of two dissimilar subdomains, A and B. The smaller subdomain B is composed entirely of alpha-helices arranged in an atypical fold, whereas the A subdomain is a variation of the alpha/beta hydrolase fold. The structure revealed the presence of a hydrophobic groove with a distal pocket at the interface of the two subdomains, which constitutes the candidate substrate binding site. The length and largely hydrophobic nature of the groove and pocket are consistent with the high selectivity of the thioesterase for palmitoyl acyl substrate. The structure also set the identity of the Asp residue of the catalytic triad of Ser, His, and Asp located in subdomain A at the proximal end of the groove.     

Effect of seminal plasma and its fractions on in vitro blastogenic response to mitogen

Five fractions of human seminal plasma were isolated on Sephadex G-100 column. The in vitro effect of whole human seminal plasma and its fractions on the lymphocyte transformation induced by phytomitogen was studied. A significant inhibition of lymphocyte response to mitogen was observed with whole seminal plasma fractions I and III at a concentration of 100-200 micrograms/ml. However fraction II stimulates the in vitro human lymphocyte transformation induced by phytomitogen at a concentration of 200 micrograms/ml. Maximum amount of inhibition by whole seminal plasma and its fractions I and III was achieved by preexposure of lymphocytes to these antigens. Pre-exposure of lymphocytes to these antigens, followed by washing, does not result in suppression of lymphocyte response to mitogen. These observations suggest that the antigens of the whole seminal plasma or of fractions I, III, and II act by simple competition with mitogen for the receptor sites on the lymphocyte membrane. Therefore, the human seminal plasma may play an immunoregulatory role against the auto- or isosensitization towards spermatozoal antigens.     

Visualization of suppressed thyroid tissue by technetium-99m-tertiary butyl isonitrile: an alternative to post-TSH stimulation scanning

The autonomously functioning thyroid nodule (AFTN) is a discrete, nodular structure which operates independently of pituitary control and without relation to the remaining thyroid tissue. Presently, for the visualization of a suppressed thyroid lobe, a patient has to undergo the thyrotropin (TSH) stimulation test, which has several disadvantages. In this study we have used tertiary butyl isonitrile (99mTc-TBI), well known as a myocardial imaging agent, for visualization of the suppressed lobe. Thirteen of fourteen patients studied demonstrated a contralateral lobe on a 99mTc-TBI scan which was not visualized with a 99mTc0(4) or 131I scan. Although it is not possible to demonstrate the autonomous nature of the hyperfunctioning thyroid nodule using 99mTc-TBI, we conclude that it is feasible to use this agent to visualize the lobe without the TSH test.     

Comparative efficacy of some benzimidazoles and amoscanate (Go.9333) against experimental filarial infections

The comparative efficacy of mebendazole, fenbendazole, oxibendazole, oxfendazole, albendazole, flubendazole and micronized amoscanate (particle size 5-8 micron) against Litomosoides carinii and Brugia pahangi infections in Mastomys natalensis was studied on administration of the compounds per os (150 mg/kg/day for 5 days) and subcutaneous (100 mg/kg/day for 5 days) routes. It was found that benzimidazoles when given by the oral route had no effect on adults of L. carinii and B. pahangi. With most of these compounds there was a rise in microfilariae before registering a fall to varying degrees in the peripheral circulation. There was a gradual but effective reduction of microfilariae of L. carinii in animals treated orally with mebendazole (99%), flubendazole (95%) and oxfendazole (85%). No such effect was seen against B. pahangi microfilariae. On subcutaneous administration, all the benzimidazoles with the exception of fenbendazole exhibited marked macrofilaricidal activity against L. carinii. Such activity was not seen with oxibendazole, oxfendazole and fenbendazole against adults of B. pahangi. Amoscanate exhibited superiority over the benzimidazoles in that the compound eliminated microfilariae and adult worms of both L. carinii and B. pahangi species when given by oral and subcutaneous routes.