Pre-mesozoic palinspastic reconstruction of the eastern great basin (Western United States).

The Great Basin of the western United States has proven important for studies of Proterozoic and Paleozoic geology [2500 to 245 million years ago (Ma)] and has been central to the development of ideas about the mechanics of crustal shortening and extension. An understanding of the deformational history of this region during Mesozoic and Cenozoic time (245 Ma to the present) is required for palinspastic reconstruction of now isolated exposures of older geology in order to place these in an appropriate regional geographic context. Considerable advances in unraveling both the crustal shortening that took place during Mesozoic to early Cenozoic time (especially from about 150 to 50 Ma) and the extension of the past 37 million years have shown that earlier reconstructions need to be revised significantly. A new reconstruction is developed for rocks of middle Proterozoic to Early Cambrian age based on evidence that total shortening by generally east-vergent thrusts and folds was at least 104 to 135 kilometers and that the Great Basin as a whole accommodated approximately 250 kilometers of extension in the direction 287 degrees +/- 12 degrees between the Colorado Plateau and the Sierra Nevada. Extension is assumed to be equivalent at all latitudes because available paleomagnetic evidence suggests that the Sierra Nevada experienced little or no rotation with respect to the extension direction since the late Mesozoic. An estimate of the uncertainty in the amount of extension obtained from geological and paleomagnetic uncertainties increases northward from +/-56 kilometers at 36 degrees 30N to (-87)(+108) kilometers at 40 degrees N. On the basis of the reconstruction, the original width of the preserved part of the late Proterozoic and Early Cambrian basin was about 150 to 300 kilometers, about 60 percent of the present width, and the basin was oriented slightly more north-south with respect to present-day coordinates.

Independent practice association physician groups in California.

We surveyed independent practice association (IPA) physician groups in California about their approaches to staffing, physician payment, and governance. Most IPAs desired more primary care physicians but not more specialists. Capitation was the major mode of remuneration for primary care physicians in 77 percent of IPAs, and for specialists in 30 percent of IPAs. Most IPAs also used financial incentives related to use of referral or ancillary services. Boards of directors were dominated by physicians, but governance tended to be centralized rather than highly democratic. We found that IPAs mirror many of the broader trends in physician staffing and physician payment that exist in managed care organizations.

Experience with 100 cases treated with botulinum-A toxin injections in the detrusor muscle for idiopathic overactive bladder syndrome refractory to anticholinergics.

PURPOSE: In this prospective, nonrandomized, ongoing study we evaluated the efficacy and safety of botulinum-A toxin injections in the detrusor muscle to treat patients with idiopathic overactive bladder resistant to conventional treatment, such as anticholinergic drugs. MATERIALS AND METHODS: A total of 23 men and 77 women with a mean age of 63 years (range 24 to 89) with nonneurogenic overactive bladder, including urgency-frequency syndrome, and incontinence despite the administration of maximal doses of anticholinergics were consecutively treated with injections of 100 U botulinum-A toxin in the detrusor muscle at 30 sites under cystoscopic guidance. Micturition diary, full urodynamics, neurological status and urine probes were performed in all participants before treatment. Bladder biopsies were done only in cases of suspected bladder fibrosis or unclear findings. Special attention was given to reflex volume, maximal bladder capacity, detrusor compliance, post-void residual urine, urgency and frequency/nocturia. Clinical, urodynamic and quality of life assessments were performed at baseline, and 4, 12 and 36 weeks after botulinum-A toxin treatment. RESULTS: Overall after 4 and 12 weeks 88% of our patients showed significant improvement in bladder function in regard to subjective symptoms, quality of life and urodynamic parameters (p <0.001). Urgency disappeared in 82% of the patients and incontinence resolved in 86% within 1 to 2 weeks after botulinum-A toxin injections. Mean frequency decreased from 14 to 7 micturitions daily (-50%) and nocturia decreased from 4 to 1.5 micturitions. Mean maximal bladder capacity increased 56% from 246 to 381 ml, mean detrusor compliance increased from 24 to 41 ml/cm H(2)O and pretreatment detrusor instability (mean reflex volume 169 ml) resolved in 74% of patients. Mean volume at first desire to void increased from 126 to 212 ml and mean urge volume increased from 214 to 309 ml. There were no severe side effects except temporary urine retention in 4 cases. Only in 8 patients was the clinical benefit poor and analysis revealed preoperative low detrusor compliance. Mean efficacy duration +/- SD was at least approximately 6 +/- 2 months and then symptoms began to increase. CONCLUSIONS: Our results show that intradetrusor botulinum-A toxin injections may be an efficient and safe treatment option in patients with severe overactive bladder resistant to all conventional treatments.

Physician supply and medical education in California. A comparison with national trends.

Concerns have been voiced about an impending oversupply of physicians in the United States. Do these concerns also apply to California, a state with many unique demographic characteristics? We examined trends in physician supply and medical education in California and the United States between 1980 and 1995 to better inform the formulation of workforce policies appropriate to the state's requirements for physicians. We found that similar to the United States, California has more than an ample supply of physicians in the aggregate, but too many specialists, too few underrepresented racial/ethnic minority physicians, and poor distribution of physicians across the state. However, recent growth in the supply of practicing physicians and resident physicians per capita in California has been much less dramatic than in the country overall. The state's unusually high rate of population growth has enabled California, unlike the United States as a whole, to absorb large increases in the number of practicing physicians and residents during 1980 to 1995 without substantially increasing the physician-to-population ratio. Due to a projected slowing of the state's rate of population growth, the supply of physicians per capita in the state will begin to rise steeply in coming years unless the state implements prompt reductions in the production of specialists. An immediate 25% reduction in specialist residency positions would be necessary to bring the state's supply of practicing specialists in line with projected physician requirements for the state by 2020. We conclude that major changes will be required if the state's residency programs and medical schools are to produce the number and mix of physicians the state requires. California's medical schools and residency programs will need to act in concert with federal and state government to develop effective policies to address the imbalance between physician supply and state requirements.