A role for dystroglycan in epithelial polarization: loss of function in breast tumor cells

Receptors mediating cell-basement membrane interactions are potent regulators of epithelial architecture and function, and alterations in signals from the basement membrane are implicated in the aberrant behavior of carcinoma cells. In this study, we have investigated the role of the basement membrane receptor dystroglycan (DG) in mammary epithelial cell function, and the significance of loss of DG function in breast tumor cell lines. Nonmalignant mammary epithelial cells express a functional DG. Analysis of multiple breast carcinoma cell lines revealed that DG is expressed in all of the cell lines examined, as evidenced by beta-DG expression, but that alpha-DG is functionally diminished in the majority. High levels of alpha-DG correlated strongly with the ability of cells to polarize in the presence of the basement membrane. Overexpression of the DG cDNA in HMT-3522-T4-2 cells elevated alpha-DG levels and altered responsiveness to the basement membrane; DG overexpression restored the ability of the cells to undergo cytoskeletal changes, to polarize, and to restrict growth in response to basement membrane proteins. Moreover, restoration of DG function to these cells greatly reduced their tumorigenic potential in nude mice. These data point to DG as an important mediator of normal cell responses to the basement membrane, and as a significant variable in carcinoma cells, in which its frequent loss can contribute to aberrant cell behavior.     

Integrating supports in assessment and planning

A systematic approach for addressing the support needs of persons with mental retardation and related developmental disabilities is presented and a new scale to measure individual differences in support needs described. The process employed in developing the scale is explained, including the establishment of a typology of support areas that was drawn from a review of the professional literature, a validation process using Q-sort methodology, and a pilot field test. Critical issues and practical challenges associated with efforts to measure and address the support needs of individuals are discussed.     

Radial glia: multi-purpose cells for vertebrate brain development

Radial glia are specialized cells in the developing nervous system of all vertebrates, and are characterized by long radial processes. These processes facilitate the best known function of radial glia: guiding the radial migration of newborn neurons from the ventricular zone to the mantle regions. Recent data indicate further important roles for these cells as ubiquitous precursors that generate neurons and glia, and as key elements in patterning and region-specific differentiation of the CNS. Thus, from being regarded mainly as support cells, radial glia have emerged as multi-purpose cells involved in most aspects of brain development.     

Community-based chlamydia and gonorrhea screening through the United States mail, San Francisco

BACKGROUND: Because gonococcal and chlamydial infections are often asymptomatic, disease control requires population-based screening. This report describes the feasibility of home-based testing for sexually transmitted diseases (STDs) and of specimen transport via the US mail. GOAL: This project sought to establish the efficacy and acceptability to the public of screening by means of urine kits made available in public places and mailed in for STD testing. STUDY DESIGN: Self-selected community participants obtained STD test kits from local businesses, collected urine specimens at home, and mailed kits to the health department for nucleic acid amplification testing. RESULTS: Participants picked up 209 test kits and returned 80 (38%): 3 (3.8%) of 76 were positive for gonorrhea and 1 (1.3%) of 76 was positive for chlamydia. The majority (95%) of participants were white gay men. The cost of specimen collection and transport was similar to that of other population-based screening programs. CONCLUSION: Using the mail for home-based testing for gonorrhea and chlamydia was feasible and may be a useful addition to STD control efforts.     

Chronic intracellular infection of alfalfa nodules by Sinorhizobium meliloti requires correct lipopolysaccharide core

Our analyses of lipopolysaccharide mutants of Sinorhizobium meliloti offer insights into how this bacterium establishes the chronic intracellular infection of plant cells that is necessary for its nitrogen-fixing symbiosis with alfalfa. Derivatives of S. meliloti strain Rm1021 carrying an lpsB mutation are capable of colonizing curled root hairs and forming infection threads in alfalfa in a manner similar to a wild-type strain. However, developmental abnormalities occur in the bacterium and the plant at the stage when the bacteria invade the plant nodule cells. Loss-of-function lpsB mutations, which eliminate a protein of the glycosyltransferase I family, cause striking changes in the carbohydrate core of the lipopolysaccharide, including the absence of uronic acids and a 40-fold relative increase in xylose. We also found that lpsB mutants were sensitive to the cationic peptides melittin, polymyxin B, and poly-l-lysine, in a manner that paralleled that of Brucella abortus lipopolysaccharide mutants. Sensitivity to components of the plant's innate immune system may be part of the reason that this mutant is unable to properly sustain a chronic infection within the cells of its host-plant alfalfa.     

The effect of glucose ingestion on endurance upper-body exercise and performance

The physiological responses to glucose supplementation during arm crank exercise were investigated. Ten subjects of mean age 28 +/- 8 years; stature 180.8 +/- 6.5 cm; mass 82.7 +/- 11.5 kg, .VO(2) peak 3.10 +/- 0.50 l x min(-1) were tested on two occasions separated by a week. A 7.6% glucose drink or placebo was administered in a blind crossover design 20 min prior to exercise. Subject's arm cranked for 60 min at an exercise intensity of 65% .VO(2)peak followed by a 20 min performance test. Rate of ventilation, oxygen uptake, RER, heart rate and blood lactate demonstrated similar responses between trials throughout the course of the hour. The blood glucose concentrations at rest were similar between trials increasing after glucose ingestion to show a significant difference (p < 0.05) to the placebo trial at the onset of exercise, then returning to resting values after 20 min. The 20 min performance tests revealed that after glucose ingestion athletes achieved a greater mean distance of 12.55 +/- 1.29 km than in the placebo trial of 11.50 +/- 1.68 km (p < 0.05). In conclusion, the results showed that after one-hour of arm crank exercise, performance over a further twenty minutes was improved when glucose was ingested twenty minutes prior to exercise.     

Field evaluation of energy expenditure in women using Tritrac accelerometers

PURPOSE: To investigate the use of Tritrac accelerometers to measure energy expenditure (EE) of various activities for women in the field setting, as compared with portable indirect calorimetry. METHODS: Twenty women (age 20-29) performed a choreographed routine of six activities (walking, jogging, stair climbing, walking on an incline, stationary cycling, and arm ergometry) while wearing a Tritrac-R3D accelerometer (Hemokinetics Inc., Madison WI) and the Cosmed K4b(2) portable metabolic cart (Cosmed, Rome, Italy). RESULTS: Comparing the mean error scores (K4b(2) - Tritrac), the Tritrac overestimated the EE (kcal x min(-1)) of walking (-1.45) and jogging (-1.75), whereas underestimating the EE of stair climbing (2.76), stationary cycling (2.75), and arm ergometry (1.20). Walking on an incline showed the lowest mean error score (-0.11). Intraclass correlations were moderate for walking (r = 0.568, < 0.05), jogging (r = 0.666, < 0.05), and stairs (r = 0.503, < 0.05) but for the other activities ranged from r = 0.290 ( > 0.05) to r = 0.480 ( < 0.05). The raw data from the Tritrac was applied to a previously developed nonlinear model to adjust the Tritrac scores to the standard of whole-room indirect calorimetry. This resulted in statistically significant improvements in the agreement between the adjusted Tritrac value and the K4b for walking, jogging, and walking on an incline ( < 0.05). CONCLUSION: When compared with portable indirect calorimetry, the Tritrac overestimates the EE of walking and jogging, whereas underestimating that of stair climbing, stationary cycling, and arm ergometry. This limits the use of such a technique to measure EE in the field. The main issues appear to be the type and intensity of the activity and the need for movement in order for the Tritrac to register EE. Activity specific linear regression equations are proposed as a tool to improve the measurement of EE using the Tritrac in the field.     

Foot and ankle fractures in the industrial setting

Fractures of the ankle and foot are common in the worker. Proper initial assessment and treatment can result in a functional recovery that is prompt and complete in many cases. Many fractures, however, have a poor long-term prognosis and prolonged recovery. Frank initial discussions with the patient and case manager can help the system better manage the patient's future.