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BACKGROUND: Kaposi's sarcoma in HIV antibody positive patients may affect the lungs. This study describes the presentation, chest radiographic appearances, and pulmonary function test abnormalities in patients with AIDS who had tracheobronchial Kaposi's sarcoma. METHODS AND RESULTS: Twenty nine (8%) of 361 consecutive HIV antibody positive patients undergoing bronchoscopy for respiratory symptoms had tracheobronchial Kaposi's sarcoma. Eight patients had intercurrent infections and one had previously received chemotherapy for cutaneous Kaposi's sarcoma; these patients were excluded. Seven of the remaining 20 patients had localised Kaposi's sarcoma (lesions confined to the trachea or the subsegments of one lobe) and 13 had widespread Kaposi's sarcoma (affecting the trachea and one lobe or the subsegments of more than one lobe); 19 patients also had cutaneous and palatal Kaposi's sarcoma. Seven patients, four with widespread disease, had a normal radiograph. All patients had reduced transfer factor (TLCO) and transfer coefficient (KCO) but only those with widespread disease had reductions in forced expiratory volume in one second (FEV1), forced vital capacity (FVC), and peak expiratory flow (PEF). Follow up pulmonary function testing in seven patients (median three months later) showed further reductions in TLCO. All four patients who received no treatment had progressive radiographic abnormalities; bronchoscopy in two patients showed progressive tracheobronchial disease, and two patients had further reductions in FEV1 and FVC. In three patients treated with chemotherapy palliation of symptoms was achieved but two had further reductions in FEV1 and FVC and the radiograph deteriorated. Bronchoscopy showed regression of disease in only one patient. CONCLUSION: Pulmonary Kaposi's sarcoma produces abnormalities of TLCO even in patients with localised disease; airflow obstruction may occur in patients with widespread disease. Bronchoscopic reassessment of the extent of disease may not accurately reflect response to chemotherapy.

A technique which identifies cells differing in surface character, aqueous two-phase partition using thin-layer countercurrent distribution (TLCCD), has been used to study differentiation and pattern formation in the developing chick limb bud. The TLCCD profiles of cell populations, derived from various regions of morphologically undifferentiated mesenchyme from three different stages of limb development, have been compared. At no stage, or location, has the population been found to be homogeneous. Cells from progress zones and more proximal regions could all be resolved into several populations. The populations from progress zones at three different developmental stages were qualitatively similar but differed in the proportions of cells in each. The most striking differences in cell populations were those obtained from the most proximal region of the limb, closest to the flank, which represents the developmentally most advanced region.

The morphogenetic capacity of prechondrogenic mesenchyme from two developmentally distinct sources was investigated in high density micromass cultures. We confirmed an earlier report (WeissMoscona, 1958) that scleral mesenchyme formed cartilage sheets whilst limb bud mesenchyme formed distinct cartilage nodules. It was thus suggested by these authors that this morphogenesis was tissue type specific. However, by varying cell density at inoculation (which controls cell configuration) and by varying the relative amount of prechondrogenic mesenchyme present in cultures we found that dramatic changes in morphogenesis could be brought about. Viewed in these terms we suggest that cartilage morphogenesis in vitro is dependent on cell configuration and the presence of non-chondrogenic cell types and hence is not necessarily a function of an intrinsic morphogenetic potential of the constituent cells.