Thrombocytopenia and hemorrhages in veal calves infected with bovine viral diarrhea virus.

The relationship between bovine viral diarrhea virus (BVDV) infection and thrombocytopenia was studied in 18 veal calves experimentally infected with BVDV. All calves were free of BVDV, and 13 calves were free of serum neutralizing antibodies to BVDV before virus inoculation. Calves were inoculated at approximately 10 days of age, and platelet counts were monitored over a period of several weeks. Ten additional calves housed in close proximity were kept as uninoculated controls. A profound decrease in platelet counts by 3 to 11 days after inoculation was seen in all calves that had neutralizing antibody titers less than 1:32 before infection. Severe thrombocytopenia (less than 5,000 platelets/microliter) was seen in 12 calves, 11 of which also developed hemorrhages. Necropsy findings in 3 severely thrombocytopenic calves that died included multiple hemorrhages throughout the body. Calves that recovered had increased platelet counts, and in most instances, a corresponding increase in neutralizing antibody titers to BVDV. At 11 days after inoculation, BVDV was detected on platelets by use of immunofluorescence, but evidence of surface-bound immunoglobulin was not found. The results suggest that a nonimmunoglobulin-mediated method of platelet destruction or sequestration develops as a sequela to BVDV infection.

Evaluation of the carbon dioxide laser on vital human primary pulp tissue.

PURPOSE: The purpose of this study was to evaluate the response of the human primary pulp to the carbon dioxide laser and formocresol for vital pulp therapy. METHODS: Fifteen healthy children with intact, caries-and-restoration-free, contralateral primary cuspids with at least two-thirds of the roots remaining who were scheduled for orthodontic extraction were randomly assigned to pulpotomy treatment with a carbon dioxide laser or formocresol. The treated teeth were clinically and radiographically evaluated at 28 and 90 days post-treatment prior to extraction. The extracted teeth were evaluated histologically for pulpal response. RESULTS: All teeth were asymptomatic and clinically normal at both observation periods. Internal root resorption was observed in one formocresol and two laser treated teeth. There was a significant inverse correlation between the laser energy applied to the pulp and the degree of inflammation at 28 days (P = .01) but not at 90 days (P = .27). CONCLUSION: Carbon dioxide laser treatment compared favorably to formocresol for pulpotomy in primary teeth.