Distribution of cytopathic and noncytopathic bovine viral diarrhea virus antigens in tissues of calves following acute experimental infection.

The distribution of cytopathic and noncytopathic biotypes of bovine viral diarrhea virus (BVDV) in the tissues of colostrum-fed and colostrum-deprived calves was investigated. Colostrum-fed (group A) and colostrum-deprived (group B) calves were experimentally infected with the BVDV isolate 80/1, which contains both BVDV biotypes. Colostrum-deprived calves were also experimentally infected with a noncytopathic BVDV (group C) or with a cytopathic BVDV (group D) cloned from the 80/1 isolate. All calves were sequentially euthanized, and a wide range of tissue samples were processed for immunofluorescent and virus isolation studies. In group A, consistent immunofluorescent staining for BVDV was detected in vascular smooth muscle of numerous blood vessels in the tissues examined, mainly at 11 and 13 days postinoculation. A predominance of samples containing cytopathic BVDV was observed in the calves of this group, following virus isolation studies. Both cytopathic and noncytopathic BVDV were detected/recovered from a larger range of specimens in the calves in group B than from the calves in group A. In the calves in all the experimental groups, large amounts of BVDV antigen were detected mainly in tissue samples from the lymphoid and gastrointestinal systems, whereas only minimal amounts of BVDV were detected in the respiratory tract. Abundant noncytopathic BVDV antigen was also detected in pituitary gland and in Langerhans islets in pancreases of colostrum-deprived calves infected with the cloned noncytopathic BVDV. Noncytopathic BVDV was isolated from a wider range of tissues from calves in group C than in the colostrum-deprived calves infected with both BVDV biotypes. A cytopathic BVDV was isolated/detected in retropharyngeal, mesenteric, and abomasal lymph nodes and in thymus of 2 calves in group C. Cytopathic BVDV was detected/isolated mainly from mesenteric lymph nodes and Peyer's patches of the calves in group D.

A comparative clinical trial of Norinyl 1 + 35 versus Norinyl 1 + 50 in Merida, Yucatan, Mexico.

A comparative clinical trial of two combined oral contraceptives differing only in estrogen type and dosage was conducted at the Centro de Investigaciones Hideyo Noguchi in Merida, Yucatan, Mexico. The trial was designed to determine the differences between Norinyl 1 + 50 (Syntex) and Norinyl 1 + 35 (Syntex) in rates of discontinuation and frequency of selected side-effects which might contribute to method discontinuation. Three hundred women were randomly assigned to either the Norinyl 1 + 35 group or to the Norinyl 1 + 50 group and follow-up visits were scheduled at 1, 4, 8 and 12 months after admission. In the Norinyl 1 + 35 group, more women experienced an increase in intermenstrual bleeding (primarily staining and spotting) (p less than 0.05), breast discomfort (p less than 0.05) and nausea than in the Norinyl 1 + 50 group. There was a significantly higher discontinuation rate for personal reasons, such as desired change of method and method not needed, among the women taking Norinyl 1 + 35 (p less than 0.05). The largest number of discontinuations comprised women discontinuing for menstrual problems in both groups. The life-table total discontinuation rate at 12 months was 52.0 for the Norinyl 1 + 35 group and 50.7 for the Norinyl 1 + 50 group. The lost-to-follow-up rates at 12 months were 17.8 for the Norinyl 1 + 35 group and 22.8 for the Norinyl 1 + 50 group.