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Biomedical subjects

B Chambers

Publications and source records attributed to B Chambers.

10 recordsLinked to original sources

U.S. Air force recruit injury and health study.

OBJECTIVES: To assess the types, rates, and risks of injury for male and female USAF recruits. DESIGN: Outpatient visits for female (5250) and male recruits (8656) were collected and analyzed for rate of injury, types of injuries, and risk of injury throughout a 6-week training period. RESULTS: One third of female recruits and one sixth of male recruits were injured at least once during recruit training. The overall rate for injuries in women and men was 63.0 and 27.8 per 1000 person-weeks, respectively. The adjusted relative risk for women versus men for all injuries was 2.22, and was consistent (1.67 to 3.27) across injury sites. Despite declining absolute rates of injury by week (106.1-13.4 for women and 53.7-13.2 for men), relative risk of injury for women versus men remained fairly constant throughout each training week. The relative risk for injury serious enough to result in medical hold was 1.69 for women vis-a-vis men. Approximately half of all medical discharges for women and men were for injuries. CONCLUSIONS: Female recruits were injured twice as often as male recruits, and were 1.5 times more likely to be removed from their training cohort for injury. Relative risk for injuries to specific body areas remained fairly consistent, indicating that no gender-specific injuries were occurring. Further efforts to determine the cause of injuries should be undertaken, and interventions aimed at reducing the disparate risk of injuries in women should be developed and evaluated.

Adolescent↗

TAP peptide transporter-independent presentation of heat-killed Sendai virus antigen on MHC class I molecules by splenic antigen-presenting cells.

Immunization of C57BL/6 (B6) mice with heat-killed Sendai virus generates a Sendai virus-specific CD8+ T cell response. This suggests that APC have the capacity to take up and present exogenous (nonreplicative) Sendai virus Ag on MHC class I molecules. Little is known about the intracellular requirements for processing of this form of Ag and its presentation on MHC class I. Therefore, we have studied the processing and presentation of heat-killed Sendai virus Ag on MHC class I molecules in splenic APC. Heat-killed Sendai virus Ags were efficiently processed by normal B6 as well as by TAP-1(-/-) splenic APC. Presentation was MHC class I restricted, since no presentation was seen by APC from TAP-1/beta2m-/- mice that lack expression of MHC class I. Presentation occurred even in the presence of brefeldin A, but was blocked by cytochalasin D as well as chloroquine. Finally, B6 as well as TAP-1(-/-) splenic APC, loaded with heat-killed Sendai virus Ag in vitro, primed naive CD8+ T cells in vivo. These studies suggest the existence of a TAP-independent pathway for Ag presentation on MHC class I in normal splenic APC, bearing many similarities with the MHC class II pathway for Ag presentation. The present results are discussed in relation to the events underlying the processing and presentation of exogenous Ag on MHC class I, the molecular basis for CD8+ T cell priming during viral infections, and prospects for vaccine development.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

Positive social interdependence and classroom climate.

We explored the relationship between student perceptions of social interdependence and social support. Attitudinal responses to the Classroom Life Instrument (Johnson & Johnson, 1983; Johnson, Johnson, & Anderson, 1983; Johnson, Johnson, Buckman, & Richards, 1985) were gathered in Canada from four classes totaling 123 eighth-grade students learning geometry in cooperative groups. We extended previous findings by examining the relationships among the classroom climate variables, causal attributions, and achievement, and explored the consistency among the four classroom climate studies using statistical methods for meta-analysis to determine overall effect magnitudes and the degree of study-to-study variability. Social support from the teacher and fellow students was moderately related to perceptions of positive interdependence, but social interdependence factors were less important predictors of student learning than was student self-esteem.

Achievement↗

Epidermal dendritic S100 positive cells in necrobiosis lipoidica and granuloma annulare.

Using an antibody to S100 protein, the number of dendritic cells above the basal layer in the epidermis was assessed in necrobiosis lipoidica and granuloma annulare. A statistically significantly higher number of these cells was found within the epidermis in necrobiosis lipoidica compared with granuloma annulare and normal skin. The numbers were similar to those seen in sarcoidosis and tuberculous reactions in the skin, which raises the possibility of an immune pathogenesis for necrobiosis lipoidica.

Cell Count↗

Erythrocyte radiolabelling: in vitro comparison of chromium, technetium, and indium in undamaged and heat damaged cells.

The stability of the commonly used red cell radio labels chromium-51, indium-(111 or 113m), and technetium-99m, within intact red cells and stroma and their distribution within the cell were compared in undamaged and heat damaged red cells in relation to the clinical use of heat damaged cells in the assessment of splenic function. Chromium-51 labelled haemoglobin both in undamaged and heat damaged cells; indium predominantly labelled haemoglobin in undamaged cells but labelled stroma in heat damaged cells, even when the cells were labelled before heating; technetium-99m predominantly labelled haemoglobin in undamaged cells but only labelled stroma in heat damaged cells if these were heated before labelling. Indium was more firmly bound by stroma prepared from heat damaged cells, and technetium-99m showed a high rate of elution both from cells and stroma, although this rate was lower for heat damaged cells.

Chromium Radioisotopes↗

Primary position upbeating nystagmus. A variety of central positional nystagmus.

We report a collaborative study of 11 patients with upbeat nystagmus in the primary position of gaze. In most cases the nystagmus behaved in accordance with Alexander's Law; in 3 patients convergence enhanced the nystagmus. Lateral gaze was without effect in 7 instances. Static tilt to prone and supine positions altered the characteristics of the nystagmus in 7 patients. The effects were variable and, in one case, there was reversal of the direction of the nystagmus to downbeating. There was pathological or radiological confirmation of lesions in the pontomedullary junction (2 cases) and the pontomesencephalic junction (2 cases). The findings support previous reports that primary position upbeat nystagmus occurs predominately with intra-axial brainstem lesions. There is one report of its occurrence with an intrinsic cerebellar lesion. Modification of the amplitude of upbeat nystagmus by tilt of the head with respect to gravity in the majority of patients implies an otolith-related component in the genesis of the nystagmus.

Adult↗

Renal disease and sarcoidosis.

Renal involvement in sarcoidosis has recently been emphasized with increasing reports of associated glomerulonephritis. We report in detail a further case of mesangiocapillary glomerulonephritis in association with sarcoidosis. In addition, a review of 75 cases of sarcoidosis at Royal Melbourne Hospital over a 10-year period revealed one case of membranous glomerulonephritis and one case of granulomatous interstitial nephritis. Seven patients in the series had nephrocalcinosis, and eight further patients had abnormalities of urinary sediment of clinical symptoms of renal involvement. These findings suggest that, though renal failure is rare, renal involvement in sarcoidosis is more frequent than has previously been reported.

Adult↗