Fibreoptic bronchoscopy in diagnosis of bronchopulmonary Kaposi's sarcoma.

Kaposi's sarcoma of the lung patients with the acquired immune deficiency syndrome is often indistinguishable by clinical and radiographic criteria from opportunistic pneumonia. Pulmonary Kaposi's sarcoma and pneumonia may frequently be present in the same patient. Previous observers have commented on the repeated failure to establish a diagnosis of Kaposi's sarcoma of the lung by fibreoptic bronchoscopy. Thirteen fibreoptic bronchoscopies were performed in a series of 11 patients with thoracic manifestations of AIDS and Kaposi's sarcoma was identified in transbronchial or bronchial biopsy specimens in four patients. This diagnostic yield is comparable to that obtained only by open lung biopsy procedures in previous reports. Fibreoptic bronchoscopy may contribute to the correct management of the patient and facilitate an accurate prognosis by differentiating between opportunistic pneumonia and pulmonary Kaposi's sarcoma

Consistency of Leadership in Shoals of Mosquitofish (Gambusia holbrooki) in Novel and in Familiar Environments

In social animal groups, an individual's spatial position is a major determinant of both predation risk and foraging rewards. Additionally, the occupation of positions in the front of moving groups is generally assumed to correlate with the initiation of group movements. However, whether some individuals are predisposed to consistently occupy certain positions and, in some instances, to consistently lead groups over time is as yet unresolved in many species. Using the mosquitofish (Gambusia holbrooki), we examined the consistency of individuals' spatial positions within a moving group over successive trials. We found that certain individuals consistently occupied front positions in moving groups and also that it was typically these individuals that initiated group decisions. The number of individuals involved in leading the group varied according to the amount of information held by group members, with a greater number of changes in leadership in a novel compared to a relatively familiar environment. Finally, our results show that the occupation of lead positions in moving groups was not explained by characteristics such as dominance, size or sex, suggesting that certain individuals are predisposed to leadership roles. This suggests that being a leader or a follower may to some extent be an intrinsic property of the individual