Previous studies have suggested that geriatric assessment units may provide important benefits to the care of elderly persons. In early 1985 we surveyed personnel at 104 (91%) of the existing 114 geriatric assessment units associated with medical schools and Veterans Administration medical centers for information on the units' development and operation. Although almost 80% of the units were hospital based, most (61%) provided care for outpatients. Nearly half (47%) began operation in 1983 or later; of those in existence before 1983, two thirds have increased their capacity since then. The types of personnel and their training differed substantially among units. Fifty percent of the physicians had had no formal training in geriatrics. Of the 104 units, 99 (95%) did routine assessment. The estimated time spent per new patient in outpatient units was 2.7 +/- 2.1 (SD) hours. These data suggest that geriatric assessment units are proliferating rapidly, have differing structures, and consume substantial resources. Further efforts are needed to define their optimal structure, targets, and function.

To learn about factors, that influence a physician's decision making, a mail survey was conducted asking physicians about their preferences for radical mastectomy vs. local excision plus irradiation, and for adjuvant chemotherapy vs. no adjuvant treatment for two hypothetical women with operable, clinical stage I breast cancer - one 35 years old and the other 60 years old. Two hundred and sixty-one physicians from varied specialties in Connecticut and Massachusetts returned the questionnaire. Approximately half of the respondents would accept either mastectomy or limited surgery plus radiation therapy for either patient. Adjuvant chemotherapy was recommended by 97% of respondents for the younger patient and by 66% for the older patient. Several factors appeared to be related to therapeutic preferences. An individual physician's attitude towards patient involvement in decision making was the most important predictor of surgical preference for both the patients, whereas the role of specialty (i.e., surgeons vs. other providers) was more important for the surgical management of the older patient. For the decision involving adjuvant chemotherapy, specialty, hospital size, and presence of radiotherapy equipment on site were important predictors. Factors other than survival (such as disease-free interval and cosmetic results) were viewed as important standards of effectiveness by some physicians.

Computer generated concentration distributions have allowed the development of numerical techniques for the determination of sedimentation and diffusion coefficients from the integrated Lamm equation; they are applicable to two component systems with minimal dependence of the characteristic parameters on concentration. Accuracy is assessed by comparison of the numerically estimated values of the relevant functions with their analytical values, as predicted by the analytical solution of the Mason-Weaver equation. These methods theoretically allow simultaneous calculation of s and D to within 0.5 % for a wide range of computer simulated data. The effects of solute heterogeneity on the results are also detailed.ß their very nature, transport processes are dynamic, involving concentration changes in both time and space, the changes being determined by the molecular parameters governing transport in a given experimental system. Thus, for 1 Equation 4a allows values of s and D to be obtained from four simultaneous equations which apply to the same time and the same field but differ in the bounds of integration, or to different times but with the same fields and bounds of integration, or lastly, to the same time and the same bounds of integration but with different fields. The first approach would appear, a priori, to be more accurate than the second, involving as it does observations made at only one time and, in the context of the experimental situation employed here (McNeil and Bethune, 1973), eliminates errors from plate misalignment. The third situation requires either two separate experiments or identification of the concentration distribution present during variation of the field within one experiment.3244 BIOCHEMISTRY, VOL.

The sensitivity and specificity of the hypertensive intravenous pyelogram and the iodohippuran renogram have been determined for the diagnosis of renovascular disease, and cost-effectiveness calculations have been made for the diagnosis and surgical treatment of patients with renovascular hypertension. When the intravenous pyelogram alone is used to screen representative hypertensive population, 78 per cent of patients with renovascular disease are located, but at the same time an equal number of patients without renovascular diasease have abnormal pyelograms. The renogram, on the other hand, is associated with varying true-positive and false-positive ratios. These data can be plotted in the form of a receiver-operating-characteristic curve. The cost of finding a patient with renovascular disease is about $2,000, and that of a surgical cure is about $20,000. The number of deaths for 100 surgical cures is approximately 15. The dollar cost of screening and treating the total American renovascular hypertensive population is of the order of 10 to 13 billion dollars.