Teratogenic evaluation of 2,4,5-T

The herbicide 2,4,5-trichlorophenoxyacetic acid is teratogenic and fetocidal in two strains of mice when administered either subcutaneously or orally and in one strain of rats when administered orally. The incidences of both cystic kidney and cleft palate were increased in the C57BL/6 mice as well as the incidence of cleft palate in the AKR mice. The incidence of cystic kidney was also increased in the rats. In addition, an increase in the ratio of liver weight to body weight in the mouse fetus and the occurrence of hemorrhagic gastrointestinal tract in the rat fetus suggest that this compound also has fetotoxic properties.     

Pseudomonas-Candida interactions: an ecological role for virulence factors

Bacterial-fungal interactions have great environmental, medical, and economic importance, yet few have been well characterized at the molecular level. Here, we describe a pathogenic interaction between Pseudomonas aeruginosa and Candida albicans, two opportunistic pathogens. P. aeruginosa forms a dense biofilm on C. albicans filaments and kills the fungus. In contrast, P. aeruginosa neither binds to nor kills yeast-form C. albicans. Several P. aeruginosa virulence factors that are important in disease are involved in the killing of C. albicans filaments. We propose that many virulence factors studied in the context of human infection may also have a role in bacterial-fungal interactions.     

Mineral composition of freshly harvested potatoes

Nine Irish potato varieties from five growing locations were assessed for mineral content to determine the contribution of the potato toward meeting the U.S. recommended daily allowances for man. With the exception of calcium, the potato is a significant source of minerals for which U.S. recommended daily allowances have been established (iron, copper, iodine, magnesium, phosphorus, and zinc).     

Experimentally induced porcine proliferative enteritis in specific-pathogen-free pigs

Thirty-three, 10-week-old, specific-pathogen-free pigs were randomly allotted to 3 treatment groups: group 1--intragastrically given homogenized intestinal mucosa (crude inoculum) from pigs with naturally occurring proliferative enteritis; group 2--given cultures of Campylobacter sputorum subsp mucosalis; and group 3--controls. One pig from each group was killed 4, 7, 10, 14, 18, 21, 24, 28, 31, 36, and 38 days after inoculation. The earliest intestinal lesion observed in groups 1 and 2 was leukocytic exudate within crypt lumina and focal inflammation of the surrounding lamina propria. The lesions occurred primarily over ileal aggregated lymphoid nodules (Peyer's patches). These changes were followed by focal proliferation of immature crypt epithelial cells and infiltration of increasing numbers of macrophages into the lamina propria. Campylobacter sp-like organisms were observed within the cytoplasm of affected epithelial cells by light and electron microscopies. Lesions progressed to diffuse crypt cell proliferation, elongation of crypts, and loss of villi. Mucosal necrosis was not a prominent feature.     

Effects of calcium channel blockers on pharmacologically induced contractions of rainbow trout (Oncorhynchus mykiss) intestine

Calcium depletion/replacement studies were carried out to examine the role of calcium in contraction of trout intestinal smoot muscle in vitro. Three chemically distinct calcium channel blockers were used to determine whether voltage operated calcium channels (VOCs) were involved in calcium entry with either agonist or depolarization-induced contractions. Contractions induced by depolarizing intestinal smooth muscle with potassium were totally dependent on extracellular calcium, whereas receptor-mediated responses to 5-hydroxytryptamine (5-HT) and carbachol also relied on calcium derived from intracellular stores. The calcium channel blockers, verapamil, nitrendipine, and diltiazem, all shifted the calcium-response curve for potassium to the right, supporting the existence of VOCs in trout intestinal smooth muscle. The calcium-response curve for 5-HT was also shifted to the right, suggesting that 5-HT can induce calcium uptake into the smooth muscle via VOCs, in addition to mobilizing intracellular calcium. Verapamil also appeared to block 5-HT receptors directly. Carbachol-induced contractions were only reduced by diltiazem at low concentrations of calcium (0.1–1 mM), suggesting that diltiazem has some other mechanisms of action than the other calcium channel blockers. Activation of muscarinic receptors may induce calcium entry through channels other than the VOCs, in addition to mobilizing intracellular calcium.