Sex effects in defensive behavior: Baseline differences and drug interactions

Female rats consistently show a pattern of differences in defensive behaviors compared to males which parallel the effects of exposure to a nonpainful threat stimulus (cat or cat odor) in the same tests and measures. These indications of greater defensiveness for females are particularly common in situations involving potential, as opposed to actual and present, threat, a factor which probably also reflects ceiling or floor effects in situations involving very intense defensiveness. In addition, pharmacological studies indicate sex differences in the effects of selective serotonin (5-HT) receptor agonists and antagonists on defensive responding. These findings indicate that sex effects must be considered in studies of the pharmacological control of defensive behaviors, and suggest that responsivity to sex effects may be an additional criterion for the suitability of animal models of anxiety.     

Incisor trauma in an adolescent Arab population: prevalence, severity, and occlusal risk factors.

INTRODUCTION: Incisor trauma is a significant clinical problem in children and adolescents. The purposes of this study were to report on the prevalence and severity of incisor trauma in a large population-based sample of adolescent Kuwaiti residents in the early permanent dentition, to determine the ages of and reasons for the injuries, and to test for any effects of sex, incisor occlusion, and lip coverage on the prevalence of incisor trauma. METHODS: Presence and type of traumatic injury were scored according to the National Institute of Dental Research index in a population-based sample of 795 girls and 788 boys with a mean age of 13.24 years (SD 0.42). RESULTS: Trauma prevalence was higher (P < .001) in boys (19.3%) than in girls (9.7%), and in the maxilla (13.6%) than in the mandible (1.5%). Most (77.3 %) of the affected subjects had only 1 injured tooth, and most (83.7%) of the traumatized teeth were maxillary central incisors. A total of 90.3% of the injuries were unrepaired enamel or enamel/dentin fractures. The major reasons for the injuries were falls and blows indoors (48.4%) or outdoors (41.6%). Nearly two-thirds (63.0%) of the traumas occurred at age 10 years or later. Mean overjet (OJ) was larger (3.9 v 3.0 mm, P < .01), and lip incompetence more frequent (12.7% v 7.3%, P < .01) among the subjects with injured maxillary incisors than among those without. Logistic regression showed that the odds of maxillary incisor trauma were 2.8 times higher in subjects with OJ between 6.5 and 9.0 mm, and 3.7 times higher in subjects with OJ > or = 9.5 mm than in subjects with OJ < or = 3.5 mm. CONCLUSIONS: Multiple logistic regression showed that the risk of maxillary incisor trauma was about 2 times higher in boys than in girls, and that the risk increased by 13% for every millimeter of increase in OJ. Lip competence was not included in the model. No associations were found between occlusion and mandibular incisor trauma.     

Cytomegalovirus induces T-cell independent apoptosis in brain during immunodeficiency.

BACKGROUND: Cytomegalovirus (CMV) is the most common opportunistic viral pathogen associated with HIV/AIDS or immunosuppressive therapy. Systemic pathology may be caused either through direct virus-mediated infection or by indirect mechanisms such as 'by-stander' apoptosis. CMV infection of the central nervous system (CNS) occurs late in disease progression and understanding of pathology in the brain is fundamental for selection of appropriate therapies. OBJECTIVES: Using a model of disseminated neurotropic CMV disease, these experiments are designed to identify cellular predilection of murine CMV (MCMV) within mature brain and to determine, if CMV induces apoptosis within CNS cells. STUDY DESIGN: Adult immunodeficient (SCID) and normal BALB/c mice were infected via the tail vein with 4.5 x 10(5)pfu recombinant MCMV expressing a green fluorescent protein reporter. Animals were perfused at various time periods from 3 to 35 days post inoculation and tissues were stained for MCMV, GFAP, NEU-N, MBP, TUNEL, and caspase-3. RESULTS: CMV infection within brain was observed in multiple, independent foci affecting several different cell types, including neurons, glial cells, meninges, ependymal cells, and cerebral vessels. Cellular changes included nuclear karyopyknosis and karyorrhexis, and associated meningitis, choroiditis, encephalitis, vasculitis, and necrosis. TUNEL and caspase-3 staining of brain-demonstrated apoptosis of nearby 'by-stander' meningial, glial, and neuronal cells, but only in immunodeficient mice lacking T- and B-lymphocytes. Generally, only large CMV infection foci were associated with apoptosis of non-infected adjacent cells. CONCLUSIONS: These results indicate that MCMV may cause both direct and indirect pathology to brain and that T-cell independent apoptosis of surrounding cells of the CNS may be an important mechanism of disease in the pathogenesis of neurotropic CMV.     

Severe Necrosis Due to Paclitaxel Extravasation

Paclitaxel is an antineoplastic agent derived from the bark of the Pacific yew tree that has activity against many tumors including breast and ovarian carcinomas. In the past, its extravasation quality has been considered to be a local irritant; however, recent reports suggest that the agent may be a vesicant. A patient experienced a delayed vesicant reaction to a paclitaxel extravasation that resulted in severe necrosis. No acute symptoms were reported at the time of extravasation from the 24-hour peripheral paclitaxel infusion. However, on day 11 the patient complained of severe and progressive pain at the site of extravasation. The site was erythematous and had areas of central necrosis requiring debridement and closure by a plastic surgeon. Because paclitaxel possesses vesicant characteristics, health care professionals should be aware of its potential extravasation hazard. Prolonged peripheral infusions should be avoided or administered with extreme caution.