A simple, rapid, cost-effective and sensitive method for detection of Salmonella in environmental and pecan samples.

AIMS: PCR is widely used in the routine detection of foodborne human pathogens; however, challenges remain in overcoming PCR inhibitors present in some sample matrices. The objective of this study was to develop a simple, sensitive, cost-effective and rapid method for processing large numbers of environmental and pecan samples for Salmonella detection. This study was also aimed at validation of a new protocol for the detection of Salmonella from in-shell pecans. METHODS AND RESULTS: Different DNA template preparation methods, including direct boiling, prespin, multiple washing and commercial DNA extraction kits, were evaluated with pure cultures of Salmonella Typhimurium and with enriched soil, cattle feces and in-shell pecan each spiked individually with Salmonella Typhimurium. PCR detection of Salmonella was conducted using invA and 16S rRNA gene (internal amplification control) specific primers. The effect of amplification facilitators, including bovine serum albumin (BSA), polyvinylpyrrolidone (PVP), polyethylene glycol (PEG) and gelatin on PCR sensitivity, was also evaluated. Conducting a prespin of sample matrices in combination with the addition of 0·4% (w/v) BSA and 1% (w/v) PVP in PCR mix was the simplest, most rapid, cost-effective and sensitive method for PCR detection of Salmonella, with up to 40 CFU Salmonella per reaction detectable in the presence of over 10(9 ) CFU ml(-1) of background micro-organisms from enriched feces soil or pecan samples. CONCLUSIONS: The developed method is rapid, cost-effective and sensitive for detection of Salmonella from different matrices. SIGNIFICANCE AND IMPACT OF THE STUDY: This study provides a method with broad applicability for PCR detection of Salmonella in complex sample matrices. This method has a potential for its application in different research arenas and diagnostic laboratories.

Physician incentives and the timing of cesarean sections: evidence from California.

OBJECTIVES: The timing of cesarean sections is studied to examine how physician convenience and financial incentives play a role in the decision to perform a cesarean section. METHODS: Using birth certificate and hospital financial data from California, the likelihood of cesarean sections being performed at particular times of day was examined, controlling for maternal characteristics and the mother's insurance coverage. Two diagnoses associated with cesarean sections are examined separately: fetal distress and prolonged/dysfunctional labor. The hypotheses are that cesarean sections performed for physician convenience are more likely to occur in the evening hours and that type of insurance will affect the incentive to perform cesarean sections to obtain leisure. RESULTS: The probability of cesarean sections for patients insured by a group-model HMO is more stable during the course of a day than that for patients insured by all other insurance plans. Group-model HMO patients with previous cesarean sections are less likely to have cesarean sections in the evening hours and are less likely to be diagnosed with fetal distress or prolonged/dysfunctional labor. CONCLUSIONS: The differences in cesarean sections and diagnosis rates between group-model HMO patients and other patients could arise from several mechanisms: group-model HMOs provide consistent financial incentives to their staff, they may be better able to guide physician practice, and they might provide staff support to physicians so there is less leisure-based incentive to perform cesarean sections. In contrast, nongroup-model HMOs do not appear to reduce the incentive of physicians to maximize leisure relative to traditional insurance.

Results of all-polyethylene tibial components as a cost-saving technique.

Since 1992, the authors have used an all polyethylene tibial component in relatively less active patients older than 70 years of age who present for primary total knee replacement. Results of 312 knee replacements performed between March 1992 and March 1998 are presented in the hopes of showing this technique as a viable cost saving measure. Three hundred twelve primary total knee replacements were performed by the same group of surgeons. Fourteen patients died before the first year postoperative evaluation, leaving an index group of 298 knees in 231 patients. All components were evaluated using the radiographic and clinical parameters of the Knee Society. Hospital for Special Surgery scores also were calculated. All patients were given the Short Form-36 Quality of Life Assessment preoperatively and annually postoperatively. Clinical scores showed dramatic improvement. There have been three revisions (0.7%) but none were for aseptic loosening. Radiographic review revealed 295 replacements with optimum fixation. To date, no patient has osteolysis. The cost differential was significant. The use of this type of tibial component has, to date, afforded excellent clinical and radiographic results. Additional followup is needed to show the longevity of these results and to monitor wear or subsidence of these prostheses. Should these results continue to prove satisfactory in this particular group of patients with relatively low physical demands, significant cost savings may be realized.

Risk adjustment of capitation payments to behavioral health care carve-outs: how well do existing methodologies account for psychiatric disability?

This study used 1994-1995 administrative data from a large public employer to examine the viability of commercial risk adjustment systems for setting capitation payments to competing behavioral health care "carve-outs". The ability of Hierarchical Condition Categories and Adjusted Diagnostic Groups to predict psychiatric expenditures was improved by controlling separately for psychiatric disability. However, even the best models underpredicted expenditures of patients with psychiatric disability by 15%. Relative to full capitation, "mixed" payment systems and soft capitation reduce the ability of carve-outs to earn disproportionate profits by enrolling healthy patients and avoiding sick ones, yet also diminish incentives for cost containment.

Explaining drug spending trends: does perception match reality?

Several recent studies have made clear that drug expenditures are rising more rapidly than other health care spending. What has not been clear, however, is how much drug spending is driven by price rather than volume and whether volume increases are appropriate. This DataWatch takes a closer look at the components and drivers of drug spending using large claims databases from managed care and employer-sponsored health benefit plans. In both environments this study found volume, not price, to be the largest driver of drug spending for seven diseases studied. For four of the diseases, we review the clinical issues that may have influenced volume growth.

How economic demand influences access to medical care for rural Hispanic children.

OBJECTIVES: In a study of access to medical care, the authors analyzed the relationship between factors influencing demand, local unmet needs, and the availability of physicians in a rural California community. METHODS: The California Department of Health Services screened 1,697 (90%) of children aged 1 to 12 years in McFarland, CA. The relation of demand to unmet needs was examined using multiple logistic regression. Factors influencing demand for medical care were: ability to pay (income, health insurance) desire to purchase care (ethnicity, education, perceived need), and incidental costs (transportation, child care, etc). Questions from the Hispanic Health and Nutrition Survey were reconstrued to fit the demand model. Local need and demand for physicians was compared with state levels to assess whether sufficient physicians were available. RESULTS: Eighty-six percent of the children were of Mexican ancestry. Factors influencing demand were linked with specific unmet needs. Although unmet needs were high, demand was low; 46% of all families were below the poverty level. Although four primary care physicians were needed, only one could be supported in the private sector because of low demand. CONCLUSIONS: Advantages to the demand model are: (1) it shows why medical services are underused and lacking in low-income areas although need is high, (2) it permits an economic rationale for extra services for poor diverse populations, (3) it estimates the amount of resources lacking to assure adequate levels of care, (4) it shows why facilitated access is needed for certain groups.

Unlicensed foreign medical graduates in California. Social and demographic characteristics and progress toward licensure.

Foreign-born physicians graduated from foreign medical schools who were unlicensed in California are described by nationality, age, sex, location, visa status, employment, English fluency, and specialty. Over 1,210 unlicensed foreign medical graduates (FMGs) were located in California and 736 were interviewed, approximately 40% of the estimated 3,000 FMGs residing in the state. Most of the FMGs who passed the ECFMG and FLEX were young, had specialty training, had studied for the examination, had participated in review courses, and were unemployed. GMENAC projections for the number of FMGs entering the residency pool to the year 1990 may be far too low, because many unlicensed FMGs are already in the country. Two thirds of the FMGs studied came to the United States after immigration of FMGs was restricted in 1977. Many were refugees or were from countries in political upheaval. Policy issues raised are the role of FMGs in improving care to the underserved, medical standards, humanitarian issues related to the resettlement of refugees and immigrants, and the projected oversupply of physicians.

Electroacoustic assessment of the semipermeable tympanic ventilating tube. A physical model.

The semipermeable membrane ventilating tube has been in use for the past few years. Initial evaluation of this tube indicated that electroacoustic impedance measurements could be used to measure in situ patency. Our clinical experience seemed to question this assumption. A physical model was developed to evaluate the validity of using electroacoustic impedance measurements to test patency of membrane-type ventilating tubes. Our results indicate that volume impedance measurements cannot be used to evaluate patency. Pressure clearance studies validated the efficacy of the membrane tubes but would not appear to be a reliable method for in vivo evaluation of patency.