Wear properties of a novel resin composite compared to human enamel and other restorative materials.

The purpose of this in vitro study was to compare the two-body wear resistance of human enamel, a pressable glass-ceramic (Imagine PressX), a type 3 gold alloy (Aurocast8), three resins composites currently available on the market (Enamel plus HRi, Filtek Supreme XTE, Ceram.X duo), and one recently introduced resin composite (Enamel plus HRi-Function). Resin composites were tested after simple light curing and after a further heat polymerization cycle. Ten cylindrical specimens (7 mm in diameter) were manufactured with each dental material according to standard laboratory procedures. Ten flat enamel specimens were obtained from freshly extracted human molars and included in the control group. All samples were subjected to a two-body wear test in a dual-axis chewing simulator over up to 120,000 loading cycles, against yttria stabilized tetragonal zirconia polycrystal cusps. Wear resistance was analyzed by measuring the vertical substance loss (mm) and the volume loss (mm(3)). Antagonist wear (mm) was also recorded. Data were statistically analyzed using one-way analysis of variance (ANOVA) (wear depth and volume loss) and Kruskal-Wallis one-way ANOVA on ranks (antagonist wear). Heat-cured HRi function and Aurocast8 showed similar mean values for wear depth and volumetric loss, and their results did not statistically differ in comparison with the human enamel.

Risk for second malignancies in non-Hodgkin's lymphoma survivors: a meta-analysis.

BACKGROUND: Late side-effects are becoming an important issue in non-Hodgkin's lymphoma (NHL) survivors. We intended to estimate pooled relative risk (RR) of secondary malignant neoplasms (SMNs), to evaluate site-associated RR and the impact of different treatments. DESIGN: We carried out an electronic search of Medline and EMBASE seeking articles investigating the risk of SMNs and reporting RR measures. The studies were evaluated for heterogeneity before meta-analysis and for publication bias. Pooled RRs were estimated using fixed- and random-effects models. RESULTS: A total of 23 studies met the inclusion criteria. Pooled RRs of SMNs overall and for solid tumors were 1.88 and 1.32, respectively. We found an excess of risk for several specific cancer sites. Radiotherapy alone did not increase the risk for SMNs, while chemotherapy and combined treatments augmented the RR. Regression analyses revealed a positive significant association for all SMNs with total body irradiation, and for solid SMNs with younger age. No publication bias was observed. CONCLUSIONS: Our results indicate that NHL patients experience a higher risk for SMNs than the general population and that various treatments have different impact on RR. More information will be necessary to evaluate possible interactions with genetic susceptibility and environmental exposure.

Automatic set-point titration for monitoring nitrification in SBRs.

Nitrification is usually the bottleneck of biological nitrogen removal processes. In SBRs systems, it is not often enough to monitor dissolved oxygen, pH and ORP to spot problems which may occur in nitrification processes. Therefore, automated supervision systems should be designed to include the possibility of monitoring the activity of nitrifying populations. Though the applicability of set-point titration for monitoring biological processes has been widely demonstrated in the literature, the possibility of an automated procedure is still at its early stage of industrial development. In this work, the use of an at-line automated titrator named TITAAN (TITrimetric Automated ANalyser) is presented. The completely automated sensor enables us to track nitrification rate trend with time in an SBR, detecting the causes leading to slower specific nitrification rates. It was also possible to perform early detection of toxic compounds in the influent by assessing their effect on the nitrifying biomass. Nitrifications rates were determined with average errors+/-10% (on 26 tests), never exceeding 20% as compared with UV-spectrophotometric determinations.

Relationship of personality traits and drug of choice by cocaine addicts and heroin addicts.

The link between specific personality profiles and a single psychotropic drug of choice is still unclear and only partially explored. The present study compares three groups of male subjects: 85 patients manifesting heroin dependence (age: 30.07 +/- 2.78), 60 patients manifesting cocaine dependence (age: 31.96 +/- 3.1), and 50 healthy subjects from a random population sample (age: 33.25 +/- 1.45). The patients included in the study showed a long-lasting history of dependence on heroin or cocaine, respectively, 5.2 +/- 2.5 years, 4.6 +/- 2.9 years, and were stabilized in treatment, and abstinent, at least 4 weeks at the time of the diagnostic assessment. Heroin addicts (52.90%) were on methadone maintenance treatment. Cocaine addicts (11.60%) were treated with selective serotonin reuptake inhibitors. Personality traits were measured by the Minnesota Multiphasic Personality Inventory (MMPI-2) and Cloninger's Three-dimensional Personality Questionnaire (TPQ). Character and quantification of aggressiveness were measured by the Buss-Durkee Hostility Inventory (BDHI). Heroin-dependent patients (group A) scored significantly higher on hysteria, masculine-feminine and social introversion subscales of the MMPI, and significantly lower on the harm avoidance (HA) subscale of the TPQ than cocaine addicts. In contrast, scores on the MMPI for hypochondria, psychopathic deviance, and paranoia dimensions were more elevated in cocaine addicts than in heroin-dependent patients. Cocaine addicts scored higher than heroin addicts on the "direct" aggressiveness subscale and on the BDHI total score. Cocaine addicts did not differ from healthy controls on harm avoidance (behavioral control). Although cocaine addicts showed more consistent psychopathic deviance and overt aggressiveness than heroin addicts, higher harm avoidance (behavioral control), hypochondria (or worry about their health), and social extroversion may reduce their proneness to overt antisocial behavior and allow relatively higher levels of social integration. The study's limitations are noted.

SBR on-line monitoring by set-point titration.

The applicability of set-point titration for monitoring biological processes has been widely demonstrated in the literature. Based on published and on-going experiences, some operating procedures have been specifically developed to be applied to SBRs, so that real-time information about the process and/or the influent can be obtained. This, in turn, would allow plant operators to select the most appropriate actions properly and timely. Five operating modes are described for the monitoring of (1) influent toxicity, (2) influent N-content, (3) nitrification capacity, (4) end of the nitrification reaction, and (5) nitrate effluent concentration, and are currently tested on the on-line titrator TITAAN (TITrimetric Automated ANalyser) which is in operation on a pilot scale SBR.

How many rural doctors do we have?

The number of physicians practicing in the nonmetropolitan areas of the United States in relation to population has increased over the past two decades, but more slowly than the number of physicians in metropolitan counties. During the same period, there was a growing acceptance of the perception that the physician work force in the United States exceeded the number necessary to meet the requirements of an efficient health care system. This has caused policy-makers to consider reforming the incentives for training physicians and restricting the entry of physicians from other countries into the United States. The supply figures on which these assessments of oversupply were made are based on "head counts" of the number of licensed, active physicians. By using more detailed data describing the licensed practicing physicians in the states of North Carolina and Washington, and by using estimates of professional activity collected as part of the Socioeconomic Monitoring System of the American Medical Association, estimates of the number of full-time equivalent physicians actually in practice in the two states and the comparative productivity of those physicians were made. Based on the state-level data, the estimates of actively practicing physicians are approximately 14 percent lower than the head-count number in North Carolina and, by using a more conservative estimation method, are approaching a 10 percent lower number than the head-count number in Washington. Using national productivity data, the effective supply of nonmetropolitan physicians appears to have not grown significantly over the past 10 years, and for family physicians the supply has declined by 9 percent. These estimates of the effective physician supply support long-held claims that rural communities continue to experience a severe undersupply of practitioners. These results suggest that the way in which physicians are counted needs to be re-examined, especially in rural places where the ratios of providers to population are more sensitive to small changes in supply.

Evolution of brain tuberculomas under standard antituberculous treatment.

The treatment of brain tuberculomas is primarily medical. Surgery, excision or biopsy, is generally performed when the diagnosis is in doubt or there is no response to medical therapy. The aim of this study was to determine the radiological evolution of intracranial tuberculomas under standard anti-tuberculous drug therapy and to establish guidelines for better management of these patients. Eighteen patients were studied retrospectively. None of them had surgical intervention and all were treated by standard antituberculous drugs and had serial computed tomography (CT) scans until disappearance or stabilization of brain lesions. The regression of lesions' size and number was slow in the first month (mean -7.3%) then became rapid after this (-15% to -20% per month). A paradoxical increase in size was noted in three patients in the first month. All three had associated meningitis. All tuberculomas disappeared on CT scan after 12 months of therapy. Most of the edema images disappeared by 6 months. This study would suggest that a long treatment regimen of 15-18 months may not be necessary in most intracranial tuberculomas occurring in non-immunocompromised patients. It also demonstrates that medical trial in well tolerated suspected cases should last for at least 2 months before considering other etiologies or surgical exploration.

Computed tomographic evaluation of gastric emphysema--a report of three cases.

We present three patients, one male and two females, who had gastric emphysema demonstrated by computed tomography (CT) by chance. All patients had adenocarcinoma of the gastric antrum resulting in gastric outlet obstruction. We have classified these as the obstructive type of gastric emphysema. An additional cause in two of our patients could be a recent biopsy at UGI endoscopy. In one patient the emphysema was localized and the diagnosis could only have been made by CT. The two other patients had the usual pattern of extensive mural gas along the greater and lesser curvature of the stomach while dissection of gas into the retroperitoneum was present in one of them. There were no systemic effects attributable to the emphysema in all three patients. This reinforces the belief that gastric emphysema is not infective in origin.

Interspecialty differences in the obstetric care of low-risk women.

OBJECTIVES: This study examined differences among obstetricians, family physicians, and certified nurse-midwives in the patterns of obstetric care provided to low-risk patients. METHODS: For a random sample of Washington State obstetrician-gynecologists, family physicians, and certified nurse-midwives, records of a random sample of their low-risk patients beginning care between September 1, 1988, and August 31, 1989, were abstracted. RESULTS: Certified nurse-midwives were less likely to use continuous electronic fetal monitoring and had lower rates of labor induction or augmentation than physicians. Certified nurse-midwives also were less likely than physicians to use epidural anesthesia. The cesarean section rate for patients of certified nurse-midwives was 8.8% vs 13.6% for obstetricians and 15.1% for family physicians. Certified nurse-midwives used 12.2% fewer resources. There was little difference between the practice patterns of obstetricians and family physicians. CONCLUSIONS: The low-risk patients of certified nurse-midwives in Washington State received fewer obstetrical interventions than similar patients cared for by obstetrician-gynecologists or family physicians. These differences are associated with lower cesarean section rates and less resource use.

Are rural family physicians comfortable performing cesarean sections?

BACKGROUND: Provision of obstetric care in the United States requires the capacity to perform cesarean sections. It is unknown who actually performs these procedures in rural hospitals and whether nonobstetricians feel comfortable performing cesarean sections. METHODS: We conducted a telephone survey of the 41 rural hospitals in Washington State, asking about the obstetric services offered and the composition and obstetrical practices of physician staff. A supplementary questionnaire was sent to the 112 family physicians providing obstetric services in the subset of hospitals with 50 or fewer beds, asking whether they performed cesarean sections. Eighty-six responded, for a response rate of 75%. RESULTS: Thirty-one (75%) of the rural hospitals provide obstetric services; of the 31 hospitals, 19 (61%) had no obstetricians on staff. In these hospitals the majority of physicians on staff both practice obstetrics and perform cesarean sections. Family physicians performed the majority of cesarean sections in all but the eight largest rural hospitals; even in these large hospitals (mean annual deliveries, 785), family physicians performed 28% of the cesarean sections. Most family physicians who performed cesarean sections felt very comfortable performing these operations. There was a strong association between the number of cesarean sections performed in formal residency training settings and the family physician's comfort level. CONCLUSIONS: Cesarean sections remain an important service in those rural hospitals providing obstetric services. Most Washington State rural hospitals depend on family physicians for this operative intervention. Physicians' comfort in doing cesarean sections appears to be closely related to prior formal training during residency. This relationship suggests that training programs preparing future rural physicians need to ensure adequate training in this area for their residents.

Rural and urban differences in physician resource use for low-risk obstetrics.

OBJECTIVE: To explore the hypothesis that rural obstetricians (OBs) and family physicians (FPs) utilized fewer resources during the care of the low-risk women who initially booked with them than did their urban counterparts of the same specialties. DATA SOURCES/STUDY DESIGN: A stratified random sample of Washington state rural and urban OBs and FPs was selected during 1989. A participation rate of 89 percent yielded 209 participating physicians. The prenatal and intrapartum medical records of a random sample of the low-risk patients who initiated care with the sampled providers during a one-year period were abstracted in detail and analyzed with the physician as the unit of analysis. Complete data for 1,683 patients were collected. Resource use elements (e.g., urine culture) were combined by standardizing them with average charge data so that aggregate resource use could be analyzed. Intraspecialty comparisons for resource use by category and overall were performed. FINDINGS/CONCLUSIONS: Results show that rural physicians use fewer overall resources in caring for nonreferred low-risk-booking obstetric patients than do their urban colleagues. Resource use unit expenditures showed the hypothesized pattern for both specialties for total, intrapartum, and prenatal care with the exception of FPs for prenatal care. Approximately 80 percent of the resource units used by each physician type were related to hospital care. No differences were shown in patterns of care for most clinically important aspects of care (e.g., cesarean delivery rates), and no evidence suggested that outcomes differed. The overall differences were due to specific components of care (e.g., fewer intrapartum hospital days and less epidural anesthesia).

Beyond retention: National Health Service Corps participation and subsequent practice locations of a cohort of rural family physicians.

BACKGROUND: This report addresses the long-term career paths and retrospective impressions of a cohort of family physicians who served in rural National Health Service Corps (NHSC) sites in return for having received medical school scholarships during the early 1980s. METHODS: We surveyed all physicians who graduated from medical school between 1980 and 1983, received NHSC scholarships, completed family medicine residencies, and served in rural areas. Two hundred fifty-eight physicians responded to our survey with complete information, 76 percent of the members of the cohort who could be located and met the study criteria. RESULTS: In 1994 one quarter of the respondents were still practicing in the county to which they had been assigned by the NHSC, an average of 6.1 years after the end of their obligation. Another 27 percent were still in rural practice. Of the entire group, less than 40 percent were in traditional urban private or managed care settings. CONCLUSIONS: Although only one quarter of NHSC assignees remain long term in their original assignment counties, they provide a large (and growing) amount of nonobligated service to those areas. Of those who leave, many remain in rural practice or work in community-oriented urban practices.

Market shares for rural inpatient surgical services: where does the buck stop?

Utilization of surgical services by rural citizens is poorly understood, and few data are available about rural hospitals' surgical market shares and their financial implications. Understanding these issues is particularly important in an era of financially stressed rural hospitals. In this study information about rural surgical providers and services was obtained through telephone interviews with administrators at Washington state's 42 rural hospitals. The Washington State Department of Health's Commission Hospital Abstract Recording System (CHARS) data were used to measure market shares and billed charges for rural surgical services. ZIP codes were used to assign rural residents to a hospital service area (HSA) of the nearest hospital, providing the geographic basis for market share calculations. "Total hospital expenses" from the American Hospital Association Guide were used as a proxy for hospital budget, and the surgical financial contribution was expressed as a ratio of billed surgical charges to total hospital expense. For rural hospitals as a whole, 21 percent of admissions and 43 percent of billed inpatient charges resulted from surgical services. In 1989, 27,202 rural Washington residents were hospitalized for surgery. Overall, 42 percent went to the closest rural hospital, 14 percent went to other rural hospitals, and 44 percent went to urban hospitals. The presence of surgical providers markedly increased local market shares, but a substantial proportion of basic surgical procedures bypassed available local services in favor of urban hospitals. For example, about one-third of patients needing cholecystectomies, a basic general surgery of low complexity, bypassed local hospitals with staff surgeons.(ABSTRACT TRUNCATED AT 250 WORDS)

Rural hospital inpatient surgical volume: cutting-edge service or operating on the margin?

Surgical services are an important part of modern health care, but providing them to isolated rural citizens is especially difficult. Public policy initiatives could influence the supply, training, and distribution of surgeons, much as they have for rural primary care providers. However, so little is known about the proper distribution of surgeons, their contribution to rural health care, and the safety of rural surgery that policy cannot be shaped with confidence. This study examined the volume and complexity of inpatient surgery in rural Washington state as a first step toward a better understanding of the current status of rural surgical services. Information about rural surgical providers was obtained through telephone interviews with administrators at Washington's 42 rural hospitals. The Washington State Department of Health's Commission Hospital Abstract Recording System (CHARS) data provided a count of the annual surgical admissions at rural hospitals. Diagnosis-related group (DRG) weights were used to measure complexity of rural surgical cases. Surgical volume varied greatly among hospitals, even among those with a similar mix of surgical providers. Many hospitals provided a limited set of basic surgical services, while some performed more complex procedures. None of these rural hospitals could be considered high volume when compared to volumes at Seattle hospitals or to research reference criteria that have assessed volume-outcome relationships for surgical procedures. Several hospitals had very low volumes for some complex procedures, raising a question about the safety of performing them. The leaders of small rural hospitals must recognize not only the fiscal and service benefits of surgical services--and these are considerable--but also the potentially adverse effect of low surgical volume on patient outcomes. Policies that encourage the proper training and distribution of surgeons, the retention of basic rural surgical services, and the rational regionalization of complex surgery are likely to enhance the convenience and safety of surgery for rural citizens.

Physician perspectives on the causes of rural hospital closure, 1980-1988.

BACKGROUND: Few studies seeking to determine the causes of rural hospital closure have examined the opinions of individuals intimately involved with the closed facilities. The purpose of this research was to examine the reasons for small sole community general hospital closures from the perspective of local physicians and to compare these reasons with the perceptions of local mayors. METHODS: Hospitals in this study were selected from a list provided by the American Hospital Association. A two-page questionnaire was sent to every physician who had practiced in the towns in which a sole community general hospital had closed between 1980 and 1988. RESULTS: Physicians reported government reimbursement policies as the most important reasons for hospital closure, agreeing with the mayors' opinions. Other reasons cited were general financial difficulties, competition from other hospitals, and bad board leadership. More than three-quarters of the physicians surveyed considered the quality of care provided by their facilities to be average or better. CONCLUSIONS: The closure of rural hospitals that physicians consider of average or better quality suggests that many of the closed hospitals could have continued to provide valuable services to the residents of their communities. Efforts must be made to ensure that rural communities are not losing viable and useful facilities.

Causes and consequences of rural small hospital closures from the perspectives of mayors.

Mayors of rural towns whose small general hospitals closed between 1980 and 1988 were surveyed. Only hospitals that were the sole hospitals in their towns and that had not reopened were included in the survey. Of the 132 hospitals meeting these criteria, 130 (98.5%) of the mayors of their communities responded to the survey. The typical study hospital had 31 beds, with an average daily census of 12. Three fourths of the hospital closures were in the North-Central and South census regions. Half of the hospital closures were for hospitals that were 20 miles or more from another hospital. Mayors attributed the closure of their hospitals primarily to governmental reimbursement policies, poor hospital management and lack of physicians. To a lesser extent, they also implicated competition from other hospitals, reputation for poor quality care, lack of provider teamwork, and inadequate hospital board leadership. Respondents reported they had little warning that their hospitals were in imminent danger of closing. Warnings of six months or less were reported by 49 percent of the mayors; only 33 percent of mayors of towns with for-profit hospitals reported having more than six months warning. Of the 132 hospital buildings that closed, only 38 percent were not in use in some capacity in the summer of 1989. Most were being utilized as some form of health care facility such as an ambulatory clinic, nursing home, or emergency room. More than three fourths of the mayors felt access to medical care had deteriorated in their communities after hospital closure, with a disproportionate impact on the elderly and poor. Nearly three fourths of the mayors also perceived that the health status of the community was worse because of the hospital closure, and more than 90 percent felt it had substantially impaired the community's economy.

The diagnosis of acute fatty liver of pregnancy by computed tomography.

We describe 2 patients with biopsy-proven acute fatty liver of pregnancy in whom the diagnosis was suggested by the finding of uniform reduced attenuation values on computed tomography (CT) of the liver. The attenuation values returned to normal with resolution of signs and symptoms following delivery. CT of the liver provides a useful method for the diagnosis of acute fatty liver of pregnancy.

Torsion of a wandering spleen.

Splenic torsion is an uncommon cause of abdominal pain. It often leads to death and seldom has been diagnosed preoperatively. We report a patient in whom the anatomy of the lesion is illustrated, together with its predisposing factors and diagnostic features.