Role of Cumulus Cells on In Vitro Maturation of Canine Oocytes

The objectives of the present study were to investigate the relationship between the morphological status of cumulus cells surrounding canine oocytes after maturation culture and the meiotic stage of the oocytes. In addition, the effect of the removal of cumulus cells from canine cumulus-oocyte complexes (COCs) during maturation culture on their meiotic competence was examined. Canine COCs were collected from bitches at the anoestrous and dioestrous stages and only COCs with >110 microm in vitelline diameter were cultured in medium 199 with 10% canine serum for 72 h. In the first experiment, the relation between the morphological status of cumulus cells surrounding oocytes cultured for 72 h and their meiotic stages was examined. At the end of maturation culture, the proportions of intact, partially nude and completely nude oocytes were 65.2%, 22.9% and 11.9%, respectively. The proportion of maturation to metaphase II of completely nude oocytes was highest among the oocytes with different morphological status of cumulus cells. In the second experiment, the cumulus cells were partially or completely removed from COCs at 48 h after the start of maturation culture and the oocytes were cultured for a further 24 h. The proportion of oocytes reaching metaphase II in the completely denuded oocytes was significantly higher than that in the control oocytes without the removal treatment of cumulus cells. The results indicate that morphological status of cumulus cells surrounding oocytes may be related to the nuclear maturation of canine oocytes, and the removal of cumulus cells from COCs during maturation culture can promote the completion of oocyte meiotic maturation.     

Quantum theory of chemical reaction dynamics

It is now possible to use rigorous quantum scattering theory to perform accurate calculations on the detailed state-to-state dynamics of chemical reactions in the gas phase. Calculations on simple reactions, such as H + D2 --> HD + D and F + H2 --> HF + H, compete with experiment in their accuracy. Recent advances in theory promise to extend such accurate predictions to more complicated reactions, such as OH + H2 --> H2O + H, and even to reactions of molecules on solid surfaces. New experimental techniques for probing reaction transition states, such as negative-ion photodetachment spectroscopy and pump-probe femtosecond spectroscopy, are stimulating the development of new theories.     

Evaluation of the components of a commercial probiotic in gnotobiotic mice experimentally challenged with Salmonella enterica subsp. enterica ser. Typhimurium

Vitacanis((R)), a probiotic preparation containing a Lactobacillus acidophilus, an Enterococcus faecium and a Saccharomyces cerevisiae, has been developed for the prevention of intestinal disorders in dogs and cats. In the present study, these microorganisms were tested jointly or singly during experimental infection of gnotobiotic mice with Salmonella Typhimurium. Four experimental groups consisting of animals given probiotics jointly or singly and a control group consisting of germfree mice were used. The groups were treated with one or three of the microorganisms (experimental) or PBS (control) 10 days before intragastric challenge with a suspension containing about 10(2) cells of the bacterial pathogen. A higher survival (P<0.05) was observed in gnotobiotic mice given E. faecium (82%). All the animals in the other groups died after the challenge but the survival time was longer (P<0.05) for groups given all three of the microorganisms (7.4+/-2.4 days) or given only L. acidophilus (7.2+/-2.9 days) than for the control mice (4.4+/-1.1 days) and the mice that received S. cerevisiae (4.9+/-1.6 days) mice. The survival data agreed with the histopathological findings which showed more severe liver and intestinal lesions in control mice and in mice given Saccharomyces. In vitro antagonistic assays showed inhibition growth of E. faecium and S. Typhimurium around the colonies of L. acidophilus and for S. Typhimurium around the colonies of E. faecium. However, in vivo, S. Typhimurium became similarly established in the digestive tract of gnotobiotic mice at levels ranging from 10(8) to 10(10)CFU/g of feces and remained at these high levels until the animals died or were sacrificed. Among the three probiotic components of the commercial product Vitacanis((R)), E. faecium was the only one that provided protection against challenge with S. Typhimurium. Protection was not due to the reduction of the intestinal populations of the pathogenic bacteria.     

Outbreak of poliomyelitis in Hispaniola associated with circulating type 1 vaccine-derived poliovirus

An outbreak of paralytic poliomyelitis occurred in the Dominican Republic (13 confirmed cases) and Haiti (8 confirmed cases, including 2 fatal cases) during 2000-2001. All but one of the patients were either unvaccinated or incompletely vaccinated children, and cases occurred in communities with very low (7 to 40%) rates of coverage with oral poliovirus vaccine (OPV). The outbreak was associated with the circulation of a derivative of the type 1 OPV strain, probably originating from a single OPV dose given in 1998-1999. The vaccine-derived poliovirus associated with the outbreak had biological properties indistinguishable from those of wild poliovirus.     

Characterization of a novel coronavirus associated with severe acute respiratory syndrome

In March 2003, a novel coronavirus (SARS-CoV) was discovered in association with cases of severe acute respiratory syndrome (SARS). The sequence of the complete genome of SARS-CoV was determined, and the initial characterization of the viral genome is presented in this report. The genome of SARS-CoV is 29,727 nucleotides in length and has 11 open reading frames, and its genome organization is similar to that of other coronaviruses. Phylogenetic analyses and sequence comparisons showed that SARS-CoV is not closely related to any of the previously characterized coronaviruses.     

Plasma concentrations of itraconazole following a single oral dose in juvenile California sea lions (Zalophus californianus)

The objective of this study was to establish a single-dose pharmacokinetic profile for orally administered itraconazole in California sea lions (Zalophus californianus). Twenty healthy rehabilitated juvenile California sea lions were included in this study. Itraconazole capsules were administered orally with food at a target dose of 5–10 mg/kg. Blood samples were collected from each animal at 0 hr and at two of the following timepoints: 0.5, 1, 2, 4, 6, 8, 12, 24, 48, and 72 hr. Quantitative analysis of itraconazole in plasma samples was performed by high-performance liquid chromatography. An average maximum concentration of 0.22 µg/ml ± 0.11 was detected 4 hr after administration. The average concentration fell to 0.12 µg/ml ± 0.11 by 6 hr and 0.02 µg/ml ± 0.02 at 12 hr. At no point did concentrations reach 0.5 µg/ml, the concentration commonly accepted for therapeutic efficacy. While this formulation was well tolerated by the sea lions, oral absorption was poor and highly variable among individuals. These data indicate that a single oral dose of itraconazole given as a capsule at 5–10 mg/kg, under the conditions used in this study, does not achieve therapeutic plasma concentrations in California sea lions.     

Accumulation of air pollutants by a Spruce Forest in Eastern Belgium

In the course of a 20 mo sampling campaign, 29 ions and elements were determined in rain water which had been collected under trees and in clearings of a spruce forest. Comparing deposition rates between these two locations gives information as to the filtering capacity of tree foliage towards air pollutants. This filtering capacity depends on the gas reactivity and on the particle diameter while pollutant accumulation rates closely depend upon meteorological conditions, mainly rainfall and duration of dry periods. Therefore, pollutant accumulation by trees should be studied on the basis of well-defined meteorological events rather than on the basis of fixed time sampling intervals, which tend to mask the strong effect of precipitation events.