East Bay Area Research Articles

The Independent Practice Association in Theory and Practice

This article examines an advanced managed care area, the San Francisco East Bay Area in California, for basic organizational issues posed by managed care for the medical profession. Of the three basic structures found, the independent practice association (IPA) model is theoretically most promising. Unlike the integrated health plan, the IPA seeks to retain traditional practice autonomy. Unlike the isolating direct gatekeeper model, the IPA assembles physicians in self-directed groups to invent and implement solutions and to exert political influence upward. In practice, however, it has proved difficult to balance practice autonomy with IPA authority. Both large, successful East Bay Area IPAs show signs (perhaps inevitably) of favoring authority over autonomy, as shown by their policies on governance, membership, and administration. Several policies are suggested to help redress this balance. Medical leaders must act now, before all the evidence is in, or the institutions of the past--hospitals and insurance companies--will control our future.

Association of paternal alcohol use with gestational age and birth weight.

Paternal alcohol use has been associated with a number of adverse reproductive outcomes in laboratory animals and there is one epidemiologic report of a detrimental effect on infant birth weight. To expand the epidemiologic evidence, data from the Child Health and Development Studies were analyzed. Data collected from the onset of prenatal care in 10,232 women enrolled in the Kaiser Foundation Health Plan and residing in the San Francisco East Bay area between June 1959 and September 1966 were available, including information on the mother's report of paternal alcohol consumption and a number of potential confounders. Pregnancy outcomes included preterm delivery (< 37 weeks completed gestation), moderately low birth weight (1,501-2,500 g), very low birth weight (< or = 1,500 g), small-for-gestational-age (< 10th percentile of weight for gestational age), and mean birth weight. Paternal alcohol use, analyzed in intervals from 0 to 2.0 or more drinks per day, showed no association with any of the outcomes of interest. Adjusted prevalence odds ratios ranged from 0.7 to 1.5, with no indication of a monotonic dose-response gradient. Mean birth weight was also virtually unrelated to paternal alcohol use. Compared with the earlier report, this population had a very modest level of alcohol consumption. Nonetheless, within the range that was studied there appears to be no association between paternal alcohol use and birth outcome.

Basin Evolution During Change from Convergent to Transform Continental Margin in Central California

Miocene nonmarine and shallow marine strata exposed east of San Francisco Bay record a change from convergent-margin tectonics to transform margin tectonics. During the middle Miocene, the East Bay area occupied the oceanward side of a shelved forearc basin that was progressively incorporated in the evolving San Andreas strike-slip orogene. Patterns of deposition in the broad forearc basin were relatively simple: andesitic arc-derived detritus was transported the full width of the forearc basin from the Sierras to the East Bay area. In contrast, the wrench-tectonic regime produced complex patterns of sedimentation displaying greater local variability. On the basis of stratigraphic data, we infer that the west-facing slope of the forearc basin in the East Bay area was reve sed about 13 Ma with uplift of the area between the eventual traces of the San Andreas and Hayward faults on the site of the present bay. A fluvial clastic wedge was shed eastward into the East Bay area from this uplifted terrane of Mesozoic subduction complex and forearc basin rocks. Initial rupturing along the Hayward fault trend followed the uplift at about 10 Ma. Loci of basaltic volcanism (10-7 Ma) along these fractures interfinger with the clastic wedge. A similar pattern of uplift and drainage reversal apparently presaged the onset of wrenching along the nearby Calaveras trend from 8-6 Ma. Expansion of the strike-slip orogene segmented the outer forearc basin into local basins, some characterized by episodic lacustrine deposition and probable internal drainage. By the end of the M ocene, Sierran arc volcanism waned at the latitude of San Francisco Bay, and arc-derived volcaniclastics were fully supplanted by recycled Coast Range-derived detritus in the East Bay area. Certain of these Coast Range sediment sources, particularly blueschist-bearing Franciscan terranes, permit an estimate of 7-27 km (4-17 mi) of total right slip on the Hayward fault.

Tectonic and Climate Controls on Sedimentation of Upper Miocene Nonmarine Strata East of San Francisco Bay, California: ABSTRACT

Upper Miocene nonmarine and shallow-marine strata exposed east of San Francisco Bay record a change from convergent-margin to transform-margin tectonics. During the late Miocene, the East Bay area occupied the oceanward side of a shelved fore-arc basin which was progressively incorporated in the evolving San Andreas strike-slip orogene. Patterns of deposition in the broad fore-arc basin were relatively simple: andesitic arc-derived detritus was transported the full width of the fore-arc basin from the Sierras to the East Bay area. In contrast, the wrench-tectonic regime produced complex patterns of sedimentation displaying greater local variability. Based on stratigraphic data from D. Wagner and our observations, we infer that the west-facing slope of the fore-arc basin i the East Bay area was reversed about 13 m.y. ago, with uplift of the area between the eventual traces of the San Andreas and Hayward faults. A fluvial clastic wedge was shed eastward into the East Bay area from this uplifted terrane of Mesozoic subduction-complex and fore-arc basin rocks. Initial rupturing along a proto-Hayward fault zone followed the uplift about 10 m.y. ago. Loci of basaltic volcanism (10 to 7 m.y.) along these fractures interfinger with the clastic wedge. A similar pattern of uplift and drainage reversal apparently heralded the onset of wrenching along the Calaveras trend 6 to 8 m.y. ago. Expansion of the strike-slip orogene segmented the outer fore-arc basin into local basins, some characterized by periodic lacustrine deposition and probable internal drainage. By he end of the Miocene, Sierran arc volcanism waned at the latitude of San Francisco Bay, and arc-derived volcaniclastics were fully supplanted by recycled Coast Range-derived detritus in the East Bay area. Certain of these Coast Range sediment sources, particularly blueschist-bearing Franciscan terranes, serve to constrain estimates of strike-slip on the Hayward fault. Although tectonics provide the principal control on patterns and composition of Neogene sedimentation in the East Bay area, late Miocene climatic fluctuations left a marked overprint. Red beds, typical of the lower upper Miocene and suggestive of seasonal aridity, correlate with a relatively cold period along the northeast margin of the Pacific Ocean. In contrast, overlying middle upper Miocene fluvial-lacustrine beds are gray brown and contain abundant carbonaceous debris and faunas indicative of a marked decrease in aridity. These strata correspond to a period of warming in the later Miocene prior to latest Miocene refrigeration (Messinian). End_of_Article - Last_Page 1689------------

The relationship between hormonal pregnancy tests and congenital anomalies: a prospective study.

In a prospective study of some 20,000 pregnancies in the Child Health and Development Studies in the San Francisco East Bay area, 226 gravidas were tested for pregnancy with estrogen/progestogen preparations. The two control groups were women who were tested for pregnancy by either a serum or urine test. There were no statistically differences (p greater than 0.05) in the rates of severe congenital anomalies between the hormone test group and the two control groups. The relative risks and the 95% confidence intervals were 1.01 (0.47-2.19) for the hormone/serum test comparison and 1.60 (0.60-4.18) for the hormone/urine test comparison.

The relationship between maternal smoking and the incidence of congenital anomalies.

The incidence of congenital anomalies among the offspring of women who never smoked, of those who were past smokers, and of those who smoked during pregnancy was examined for 14,735 children who were members of the Kaiser Foundation Health Plan, a prepaid medical care program in the San Francisco East Bay Area of California. The children were offspring of mothers enrolled in the Child Health and Development Studies, a longitudinal study of pregnancy and the normal and abnormal development of offspring. There were no significant differences in the incidence of congenital anomalies when smokers (all dose levels combined) were compared with those who had never smoked. While there was a slight decrease in the incidence of congenital anomalies among light smokers, a significant difference was observed when the incidence of congenital anomalies among the offspring of women who smoked 20 or more cigarettes daily was compared with that observed among the offspring of women who never smoked. The increase in incidence associated with heavy smoking occurred predominantly among male offspring and was attributed to anomalies classified as moderate. The incidences of two specific anomalies, inguinal hernia and strabismus, were observed to increase significantly when the mothers had smoked during pregnancy. A significant decrease was observed in the incidence of moderate musculo-skeletal anomalies among the male offspring of smokers. The differing nature of the various associations noted stresses the complexity of underlying causal mechanisms.

The relationship of maternal attitude to pregnancy outcomes and obstetric complications: A cohort study of unwanted pregnancy

The relationships of maternal attitude to pregnancy outcome and obstetric complications were investigated in a prospective study of a group of 8,000 gravidas, enrolled in the Child Health and Development Studies, who were members of the Kaiser Foundation Health Plan in the San Francisco East Bay Area. Interviews which were conducted early in pregnancy determined the mother's attitude thorugh an open-ended question, “How do you feel about having a baby now?” The responses to this question were categorized as strongly favorable, ambivalent, or negative. Biomedical factors which were related to negative maternal attitude were perinatal death, congenital anomalies, and postpartum infection or hemorrhage. Other factors which were found to be related to maternal attitude toward pregnancy were clinic visits for psychosocial complaints related to anxiety states, and accidental injuries during pregnancy, as well as need for analgesics during labor. Birth weight of the infant, duration of gestation, length of labor, prenatal complications, and intrapartum obstetric complications were not related to maternal attitude. In order to control for the effect of confounding factors, these relationships were analyzed by using a multicontingency table approach and stratifying the data by parity, age of mother, and socioeconomic status.

Ambient and dynamic pore pressures in fine-grained submarine sediments: Mississippi Delta

A multisensor piezometer probe has measured pore pressures in fine-grained submarine sediments of the Mississippi Delta over a period of approximately eight months. Data presented here cover the initial 2650 hours of the experiment. Dynamic and ambient pore pressures were recorded. Analogue data collected from the time of probe insertion include decay characteristics, steady-state (ambient) excess pore pressures, and the response of pore pressures to surface wave activity. The probe was installed in 43–44 ft of water near an offshore platform in the East Bay area of the Delta. Sensors were located at 21, 41 and 51 ft below the mudline. Ambient excess pore pressures were determined to be 0.7, 2.8 and 6.6 psi (lb/in 2) at the respective depths. The relatively high excess pressures and the measured laboratory wet unit weights of the soil result in a significantly low effective stress. Pressure fluctuations due to tidal and surface wave activity were observed to produce significant pore pressure response in these soils. Preliminary data obtained using high-airentry and corundum stones indicate that considerably more research is necessary in order to fully understand the peculiarities observed in the data and to assess the role of dissolved and free gas on the pore pressures in submarine sediments.

Geology and geotechnical characteristics of sediments in east bay area, Mississippi delta

Abstract Deltaic sedimentation has produced an accumulation of clay and silt with a maximum thickness of 90 m in East Bay area. Sediments in the upper 50 m grade from interbedded sand, silt, and clay near South Pass and Southwest Pass to predominantly clay in the central part of the area. The variation in the types of sediments and rates of deposition greatly affected the engineering properties of these deposits. Sediments from boreholes in the central part of the area have shear strengths of less than 10 kPa to a depth of at least 50 m. Near the distributaries, shear strength increases with depth; values as high as 43 kPa were measured in sediments in the upper 50 m. These sediments are generally stronger and coarser, and have a lower water content and liquid limit than do sediments at comparable depths in the central part of the area.

Archaean Sedimentation: Analysis of the Minnitaki Basin, Northwestern Ontario, Canada

Four main facies have been identified in the East Bay area of Minnitaki Lake. The first consists of coarse arkose and arkosic conglomerate. Individual beds are commonly graded but lack other sedimentary structures. Plagioclase makes up 30 to 40 percent of the rock, and quartz about 6 percent. The second consists of graded graywackes interbedded with slates. Quartz here reaches about 20 percent, plagioclase only 15 percent, and rock fragments 10 to 15 percent. The third facies consists of graded conglomerates with abundant very well-rounded granite boulders up to 40 cm in diameter, and the fourth facies is a black slate with very thin (1 to 5 cm) graded siltstones. The slate is the background sediment of the basin, and is interbedded with the arkoses, arkosic conglomerates, graywackes, and granite-bearing conglomerates. Mapping and measuring has revealed an almost unbroken stratigraphic column 800 m thick. Arkoses and arkosic conglomerates are restricted to the basal 150 m, and above this level there is a gradual increase in the ratio of quartz to feldspar. The graywackes are interpreted as turbidites, and the graded conglomerates as a very proximal resedimented facies. There is no evidence of shallow, agitated water sediments. Transport of the arkosic conglomerates was westward along the present tectonic strike, and the source area, a quartz-porphyry stock, has been identified at the eastern end of the basin. The quartz-rich graywackes and granite-bearing conglomerates indicate a granite or granite-gneiss source area, devoid of greenstone cover, because greenstone debris is very rare in the sediments. The gradual increase in quartz during basin filling suggests progressive uplift of the terrain bordering the trough, with steep shorelines and no development of marginal facies.

Attitudes of Individual California Physicians and Policies of State Medical Societies on Vasectomy for Birth Control

Since vasectomies are usually performed in a doctors office and reporting is not required a questionnaire was sent to all active members of a 2-county medical association in the East Bay area of San Francisco in 1964 to elicit their attitudes beliefs and experiences with voluntary vasectomy. There was general approval for the procedure and 30% of the responding (877) doctors had performed one or more operations. 90% of the operations were done by general practitioners urologists and surgeons. Extrapolation from the figures for this area indicates that approximately 200000 vasectomies may be done yearly in the whole country. Psychiatrists tended to disapprove more than other specialties feeling it harmful psychologically to the patient. The main reason for objecting was that the man may later change his mind and regret having done it. 53% of all reversal operations have resulted in viable sperm and 23% so far in conceptions. Some vasectomy operations have been unsuccessful due to spontaneous recanalization or the males neglecting to have a sperm count before considering himself safe. The legal status of vasectomies is still unclear in almost all states.

Tracheostomy: Present day indications and technics

0 NE OF THE oldest surgicaI procedures for sustaining Iife under emergency conditions is that of tracheostomy; we find it first mentioned by AscIepiades of Dithyma in 124 B.C. [I]. There is further mention of this operation in the days of Pompeii by a daring and capabIe surgeon, PauI of Agenia in 6go A.D. [2]. Coming to somewhat more modern times, Armond Trousseau was the first to perform tracheostomy in Paris, and for his brilIiant treatise on the subject, he received the coveted prize of the Academy of Medicine [3]. This procedure proved to be of such worth that American physicians were rapid to adopt its use and a number of pioneers in this country are listed in our historica writings. With this ancient background, it is obvious that the operation is no new story in medicine, nor is it our intention to suggest anything that might Iead to a comphcation of the simpIe methods of this very oId operation of opening the windpipe. Recent experience, however, pfompted the recording of present day uses of a modaIity sometimes considered appIicabIe onIy ih the direst of emergencies, as a Iast gasp procedure. The experience of ourseIves and many others [4-71 in the past decade does in no way suggest that “something new had been added,” but rather that “something oId has been expanded.” The broader use of tracheostomy in situations more Iifesustaining rather than actuaIIy Iife-saving seems worthy of consideration. The performance of this operation in the hospita1 bed, x-ray department, or in areas otherwise not surgicaIIy adapted seems to us rareIy necessary. We are not inclined to agree with recent reports in which the favored IocaIe was at the bedside [8]. Signs, symptoms and prodroma1 warnings are suffIcientIy we11 estabhshed to permit ampIe time for forma1 scheduIing of this operation in the surgica1 amphitheater where the operation can be done under idea1 surroundings and with the frequentIy needed support of our anesthesioIogy coIIeagues. This phiIosophic attitude with reference to respiratory probIems of this type admittedIy pIays a major roIe in surgica1 judgment and in the handIing of each individual patient. If, in our consuItative evaIuation of a given case, tracheostomy is a subconscious suggestion, in most instances evidence is probabIy sufficient to warrant immediate pIanned surgery. It is with these precepts in mind that we wouId Iike to present this cIinica1 experience. Our series incIudes that of the writers, thoracic surgica1 attendings, genera1 surgeons and residents in hospitaIs Iocated throughout the greater East Bay Area. These procedures were performed during a five year period from JuIy 1957 through June 1962 and totaIIed 461 cases. TabIe I, Iists the indications for which tracheostomy was performed in this series. The deaths, al1 but five of which were beIieved due to the underlying pathoIogy, wiII be discussed Iater.

A Regional Library Service for the East Bay Area.

A Regional Library Service for the East Bay Area.