Pulmonary function in asymptomatic adolescents with idiopathic scoliosis.

Pulmonary function studies were performed in 28 asymptomatic adolescents with idiopathic scoliosis. Tests included spirometry, flow volume curve, measurements of inspired gas distribution, diffusing capacity, closing volume, ventilatory response to carbon dioxide, and arterial blood gas analysis. In addition to the well-known decreases in lung volumes, a reduction in diffusing capacity, arterial oxygen tension, and ventilatory response to carbon dioxide were also documented. Significant correlations existed between the severity of the spinal curvature and the decrease in lung volumes. A significant correlation was also found between the degree of hypoxemia and the reduction in the diffusing capacity, suggesting that a low diffusing could be the cause of the observed arterial hypoxemia.     

Effects of incarceration on HIV-infected individuals.

Human immunodeficiency virus (HIV) infection is a critical problem among the incarcerated population, with rates as high as 17% being reported for prison systems in New York. The literature suggests that stressful living conditions and inherent defects in the immune system associated with HIV infection make prison populations more susceptible to a disproportionate decrease in their CD4 counts. To determine the effects of incarceration on HIV-infected individuals, the charts of 800 inmates were reviewed. Baseline (draw 1), 2- to 5-month (draw 2), and 6- to 12-month (draw 3) CD4 cell counts were obtained. Mean cell counts were calculated, and paired t-tests were used to identify differences. The group receiving antiretrovirals throughout showed no difference in mean CD4 cell count between draws 1 and 2 or between draws 1 and 3. The group not receiving HIV medications did not show a significant difference in CD4 cell counts between draws 1 and 2, but did show a significant difference between draws 1 and 3. For this group, the rate of decline in CD4 cells was greater than among an outpatient setting. The subsample of subjects initiating therapy prior to the second blood draw showed a significant increase in mean CD4 cell counts at draw 1 versus draw 2, but did not show a significant change when comparing draw 1 to draw 3. When examining subjects based on their antiviral status, the mean CD4 cell count at each of the draws was statistically associated with subjects'' antiviral status. We conclude that incarceration causes a more rapid decrease in CD4 cells compared with an outpatient population, causing clinical significance on the normal course of HIV disease.     

SELECTIVE ENDOSCOPY IN MANAGEMENT OF INGESTED FOREIGN BODIES OF THE UPPER GASTROINTESTINAL TRACT: IS IT SAFE?

During a four-year period, 308 patients presented following ingestion of foreign bodies. Ingestion was accidental in 272 cases (88.3%) and deliberate in the remainder. Symptoms at presentation included dysphagia, odynophagia, nausea and vomiting, chest pain and pharyngeal discomfort. Sixty-eight patients were asymptomatic. A policy of expectant management and selective endoscopy was employed. Following initial assessment 202 patients (65.6%) were discharged without treatment, 30 (9.7%) of whom were later reviewed as outpatients and did not require admission. Forty-nine patients (16%) were admitted for treatment; 27 had oesophagoscopy, five bronchoscopy and two had foreign body extraction with direct laryngoscopy. In nine patients who were endoscoped, no foreign body was identified. Twenty-seven others were referred to the otorhinolaryngology service in another hospital. There were no deaths in the group and morbidity was 1.2%. We conclude that a policy of selective endoscopy is safe and effective in the management of patients following ingestion of foreign bodies.     

Passive optical separation within a 'nondiffracting' light beam

A passive, optical cell sorter is created using the light pattern of a 'nondiffracting' beam-the Bessel beam. As a precursor to cell sorting studies, microspheres are used to test the resolution of the sorter on the basis of particle size and refractive index. Variations in size and, more noticeably, refractive index, lead to a marked difference in the migration time of spheres in the Bessel beam. Intrinsic differences (size, refractive index) between native (unlabeled) cell populations are utilized for cell sorting. The large difference in size between erythrocytes and lymphocytes results in their successful separation in this beam pattern. The intrinsic differences in size and refractive index of other cells in the study (HL60 human promyelocytic leukaemic cells, murine bone marrow, and murine stem/progenitor cells) are not large enough to induce passive optical separation. Silica microsphere tags are attached to cells of interest to modify their size and refractive index, resulting in the separation of labeled cells. Cells collected after separation are viable, as evidenced by trypan blue dye exclusion, their ability to clone in vitro, continued growth in culture, and lack of expression of Caspase 3, a marker of apoptosis.     

Synergistic cytotoxic effect of azidothymidine and recombinant interferon alpha on normal human bone marrow progenitor cells

Azidothymidine (AZT) and interferon alpha (IFN-alpha) are among the drugs showing strong in vitro activity against the human immunodeficiency virus type-1 (HIV-1). Each drug, however, has significant toxicity against normal marrow progenitor cells that frequently proves dose-limiting in patients. In this study, AZT and recombinant IFN-alpha 2a (rIFN-alpha 2a) were tested as single agents and in combination against normal myeloid (CFU-GM) and erythroid (BFU- E) colony forming cells in a standard methylcellulose culture assay. The data were analyzed using a quantitative computerized analysis based on the median-effect principle and the isobologram equation as described by Chou and Talalay (Adv Enz Regul 22:27, 1984). The ED90 for BFU-E and CFU-GM inhibition was then compared with previously measured in vivo plasma levels of each drug and the ED90 for the anti-HIV-1 effect in vitro. We demonstrate that (a) the drugs are strongly synergistic in inhibiting marrow progenitor cell growth and that this synergism occurs at drug levels that are within the range of measured plasma levels in phase I clinical trials, (b) BFU-E are more sensitive than CFU-GM to the inhibiting effects of AZT, rIFN-alpha 2a or both drugs in combination, (c) the drug concentrations in combination that synergistically inhibit bone marrow progenitors are much higher than those required to inhibit HIV-1 replication in vitro, and (d) the anti- HIV-1 effect for the combination of AZT and rIFN-alpha 2a was clearly superior to the effect of AZT or rIFN-alpha 2a alone as indicated by the combination index and the dose-reduction index. These data suggest that substantially lower doses of AZT and rIFN-alpha than those currently being tested in clinical trials might not only maintain a strong synergistic anti-HIV-1 effect but might also avoid significant hematologic toxicity.