Virulence is a microbial property that is realized only in susceptible hosts. There is no absolute measurement for virulence, and consequently it is always measured relative to a standard, usually another microbe or host. This article introduces the concept of pathogenic potential, which provides a new approach to measuring the capacity of microbes for virulence. The pathogenic potential is pro...

The impact of pesticides on amphibians is of particular concern because their populations appear to be declining on a global scale. We examined the toxic and genotoxic effects of malathion, a commonly used organophosphorus pesticide, in the larvae of Indian skittering frog (Euflictis cyanophlyctis). The different concentrations of malathion (0, 0.5, 1.0, 2.0, 4.0 and 8.0mg/L) tested in a 2×6 fa...

A Salmonella typhimurium strain harboring stable mutations in both ompC and ompF was constructed from the mouse-virulent strain S. typhimurium SL1344. When administered orally to BALB/c mice the strain was attenuated, with the 50% lethal dose (LD50) reduced by approximately 1,000-fold. However, the intravenous LD50 was reduced only by approximately 10-fold. The ompC ompF mutant persisted in mur...

The potential effects of enflurane, isoflurane, halothane, fluroxene and nitrous oxide on mortality and fertility in Drosophila melanogaster were examined. The LD50 value 1 day after exposure for 1 h was the same for males and females and was about 8% for enflurane, isoflurane and halothane, about 20% for fluroxene, and greater than 100% for nitrous oxide. Male and female fertility, however, we...

The effect of the pesticide endosulfan on predator-prey interactions between catfish and Schistosoma host snails was assessed in static tank experiments. Hybrid catfish (Clarias gariepinus × C. ngamensis) and Bulinus globosus were subjected to various endosulfan concentrations including an untreated control. The 48- and 96-h LC50 values for catfish were 1.0 and <0.5 µg/L, respectively, whereas ...

Two novel crystal protein genes, cry30Ba and cry44Aa, were cloned from Bacillus thuringiensis subsp. entomocidus INA288 and expressed in an acrystalliferous strain. Cry44Aa crystals were highly toxic to second-instar Culex pipiens pallens (50% mortality concentration [LC50] = 6 ng/ml) and Aedes aegypti (LC50 = 12 ng/ml); however, Cry30Ba crystals were not toxic.

Cypermethrin was administered to Heteropneustes fossilis in chronic concentration to determine lesion of liver as indicators of tissue damage. The cypermethrin dose used was 1/4 of 96 hr LC50. Histopathological changes in liver ranged from vacuolization, necrosis, fibrosis of perivascular region and disposition of yellow brown grains at different time of exposure viz; 20th, 30th, 40th and 60th ...

INTRODUCTION PATHOPHYSIOLOGY Hematopoietic Syndrome Gastrointestinal Syndrome Neurovascular Syndrome DETERMINANTS OF RADIATION EFFECTS ON HUMANS Lethality Curve Influence of Trauma on LD50 Effect of Clinical Support on the LD50 Dose Effect Curve CLINICAL ASPECTS OF THE US CRITICALITY EXPERIENCE Clinical Course of the Criticality Cases CURRENT TREATMENT OF ACUTE RADIATION SYNDROME Supportive Car...

Malaria is considered a major health problem in Iran. There are different methods for vector control. In this study we tested the larvicidal effects of some Iranian plants. The methanolic extracts of 11 plants were prepared with percolation method. The larvicidal activities of them against malaria vector, Anopheles stephensi were studied using World Health Organization standard method. All LC50...

Pyrethroid resistance in bed bugs, Cimex lectularius, has prompted a change to combination products that include a pyrethroid and a neonicotinoid. Ten populations of bed bugs were challenged with two combination products (Temprid SC and Transport GHP). Susceptibility of these populations varied, with the correlated response of the two products indicating cross resistance. We imposed selection o...