Fourteen of 174 patients receiving maintenance dialysis volunteered to participate in a 12-week exercise conditioning program. Seven patients attended more than 50% (range, 55 to 75%) of the sessions held three times each week. These seven patients achieved a 42% (P less than 0.05) improvement in work capacity as assessed by maximal oxygen consumption during treadmill testing. No changes occurred in psychologic functioning, blood pressure control, hematocrit, or left ventricular ejection fraction. Seven patients attended fewer than half of the sessions (range, 1 to 38%) and did not demonstrate improved exercise capacity. Psychologic testing at entry revealed that those who did not attend regularly had higher scores for hostility, anxiety, and depression as compared to those patients who completed the program. No other clinical variables distinguished those who had good attendance records from those who did not. We conclude that exercise conditioning can improve physical work capacity in patients with chronic renal failure who are receiving maintenance dialysis treatment. Despite this potential benefit, the impact of exercise conditioning programs such as this may be limited because only a small portion of patients on maintenance dialysis are able or willing to participate to an extent sufficient to induce physiological changes.

Polymorphism, in which there exist different crystal forms for the same chemical compound, is an important phenomenon in pharmaceutical manufacturing. In this article, a kinetic model for the crystallization of L‐glutamic acid polymorphs is developed from experimental data. This model appears to be the first to include all of the transformation kinetic parameters including dependence on the temperature. The kinetic parameters are estimated by Bayesian inference from batch data collected from two in situ measurements: ATR‐FTIR spectroscopy is used to infer the solute concentration, and FBRM that provides crystal size information. Probability distributions of the estimated parameters in addition to their point estimates are obtained by Markov Chain Monte Carlo simulation. The kinetic model can be used to better understand the effects of operating conditions on crystal quality, and the probability distributions can be used to assess the accuracy of model predictions and incorporated into robust control strategies for polymorphic crystallization. © 2008 American Institute of Chemical Engineers AIChE J, 2008

College students with insulin-dependent diabetes mellitus often ignore the care of their illness. Faced with managing this illness independently for the first time, they lack the knowledge and experience to do so effectively. Their need to establish autonomy often prevents them from seeking the advice of health professionals. In view of this, the author undertook a pilot study to investigate the role of a peer support group on a college campus as a means of improving the diabetic students' management of their illness. Three closed-membership groups met for 10 weekly sessions. Hemoglobin A1c (the measure of average blood sugar over the preceding 3-month interval) determinations prior to participation in the group ranged from 4.0 to 11.7, with a mean of 8.16; after participation in the group, the mean hemoglobin A1c levels of group members dropped to 6.10 (p less than .001). (Hemoglobin A1c measures lower than 6.2 reflect physiologic blood sugar measures of someone without diabetes.) These results suggest that the peer-group approach may be a viable way to improve the metabolic control of young adults with diabetes at the time in their lives when they are learning to manage their illness independently.

Mediated uptake of amino acids by membrane vesicles isolated from Balb/c 3T3 cells transformed by simian virus 40 has been demonstrated. Initial rates of transport of radioactively labeled L-leucine and a-aminoisobutyric acid were enhanced by the addition of NaCl (100 mM) to the reaction mixture at the start of the uptake process. This enhancement included a prominent "overshoot" during initial uptake. Slight stimulation of a-aminoisobutyric acid uptake was seen with K+, but none with Li+. The mediated nature of the uptake event for L-leucine was shown by saturation kinetics and by inhibition with L-valine. The transport assay measured predominantly intravesicular amino aciduptake rather than binding, as shown by the variation of uptake in response to changes in extravesicular osmolarity. Electron microscopy confirmed the presence of closed vesicles. Thus, amino acid transport has been characterized in an in vitro membrane vesicle system which should prove useful for studies of growth control. For more than two decades the cell surface membrane has been a focus for the study of differences between tumor cells and normal cells. Studies relating growth regulation to nutrient transport (1-6) have shown that the rate of cellular uptake of certain amino acids, sugars, and nucleosides decreases when growing, untransformed cells reach a confluent, "contact-inhibited" monolayer. Uptake rates have also been shown to increase when the cells are virally transformed. Pardee and coworkers (7,8) and Holley (9) have suggested that these transport variations observed in whole cells reflect primary alterations in the cell membrane, and that malignant growth is made possible by the resulting increase in nutrient supply. However, transport studies on whole cells present the problem of distinguishing between membrane-localized alterations and changes in intracellular metabolism.Attempts have been made to separate uptake from subsequent metabolism by the use of nonmetabolizable analogs.

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