Preferences for physical activity: a conjoint analysis involving people with chronic knee pain.

OBJECTIVE: To investigate individual preferences for physical activity (PA) attributes in adults with chronic knee pain, to identify clusters of individuals with similar preferences, and to identify whether individuals in these clusters differ by their demographic and health characteristics. DESIGN: An adaptive conjoint analysis (ACA) was conducted using the Potentially All Pairwise RanKings of all possible Alternatives (PAPRIKA) method to determine preference weights representing the relative importance of six PA attributes. Cluster analysis was performed to identify clusters of participants with similar weights. Chi-square and ANOVA were used to assess differences in individual characteristics by cluster. Multinomial logistic regression was used to assess associations between individual characteristics and cluster assignment. RESULTS: The study sample included 146 participants; mean age 65, 72% female, 47% white, non-Hispanic. The six attributes (mean weights in parentheses) are: health benefit (0.26), enjoyment (0.24), convenience (0.16), financial cost (0.13), effort (0.11) and time cost (0.10). Three clusters were identified: Cluster 1 (n = 33): for whom enjoyment (0.35) is twice as important as health benefit; Cluster 2 (n = 63): for whom health benefit (0.38) is most important; and Cluster 3 (n = 50): for whom cost (0.18), effort (0.18), health benefit (0.17) and enjoyment (0.18) are equally important. Cluster 1 was healthiest, Cluster 2 most self-efficacious, and Cluster 3 was in poorest health. CONCLUSIONS: Patients with chronic knee pain have preferences for PA that can be distinguished effectively using ACA methods. Adults with chronic knee pain, clustered by PA preferences, share distinguishing characteristics. Understanding preferences may help clinicians and researchers to better tailor PA interventions.

Mortality Risk Factors Among Patients With Cirrhosis and a Low Model for End-Stage Liver Disease Sodium Score (≤15): An Analysis of Liver Transplant Allocation Policy Using Aggregated Electronic Health Record Data.

Although the Model for End-Stage Liver Disease sodium (MELD Na) score is now used for liver transplant allocation in the United States, mortality prediction may be underestimated by the score. Using aggregated electronic health record data from 7834 adult patients with cirrhosis, we determined whether the cause of cirrhosis or cirrhosis complications was associated with an increased risk of death among patients with a MELD Na score ≤15 and whether patients with the greatest risk of death could benefit from liver transplantation (LT). Over median follow-up of 2.3 years, 3715 patients had a maximum MELD Na score ≤15. Overall, 3.4% were waitlisted for LT. Severe hypoalbuminemia, hepatorenal syndrome, and hepatic hydrothorax conferred the greatest risk of death independent of MELD Na score with 1-year predicted mortality >14%. Approximately 10% possessed these risk factors. Of these high-risk patients, only 4% were waitlisted for LT, despite no difference in nonliver comorbidities between waitlisted patients and those not listed. In addition, risk factors for death among waitlisted patients were the same as those for patients not waitlisted, although the effect of malnutrition was significantly greater for waitlisted patients (hazard ratio 8.65 [95% CI 2.57-29.11] vs. 1.47 [95% CI 1.08-1.98]). Using the MELD Na score for allocation may continue to limit access to LT.

Applying the WHO conceptual framework for the International Classification for Patient Safety to a surgical population.

OBJECTIVE: Efforts to improve patient safety are challenged by the lack of universally agreed upon terms. The International Classification for Patient Safety (ICPS) was developed by the World Health Organization for this purpose. This study aimed to test the applicability of the ICPS to a surgical population. DESIGN: A web-based safety debriefing was sent to clinicians involved in surgical care of abdominal organ transplant patients. A multidisciplinary team of patient safety experts, surgeons and researchers used the data to develop a system of classification based on the ICPS. Disagreements were reconciled via consensus, and a codebook was developed for future use by researchers. RESULTS: A total of 320 debriefing responses were used for the initial review and codebook development. In total, the 320 debriefing responses contained 227 patient safety incidents (range: 0-7 per debriefing) and 156 contributing factors/hazards (0-5 per response). The most common severity classification was 'reportable circumstance,' followed by 'near miss.' The most common incident types were 'resources/organizational management,' followed by 'medical device/equipment.' Several aspects of surgical care were encompassed by more than one classification, including operating room scheduling, delays in care, trainee-related incidents, interruptions and handoffs. CONCLUSIONS: This study demonstrates that a framework for patient safety can be applied to facilitate the organization and analysis of surgical safety data. Several unique aspects of surgical care require consideration, and by using a standardized framework for describing concepts, research findings can be compared and disseminated across surgical specialties. The codebook is intended for use as a framework for other specialties and institutions.

Preventable errors in organ transplantation: an emerging patient safety issue?

Several widely publicized errors in transplantation including a death due to ABO incompatibility, two HIV transmissions and two hepatitis C virus (HCV) transmissions have raised concerns about medical errors in organ transplantation. The root cause analysis of each of these events revealed preventable failures in the systems and processes of care as the underlying causes. In each event, no standardized system or redundant process was in place to mitigate the failures that led to the error. Additional system and process vulnerabilities such as poor clinician communication, erroneous data transcription and transmission were also identified. Organ transplantation, because it is highly complex, often stresses the systems and processes of care and, therefore, offers a unique opportunity to proactively identify vulnerabilities and potential failures. Initial steps have been taken to understand such issues through the OPTN/UNOS Operations and Safety Committee, the OPTN/UNOS Disease Transmission Advisory Committee (DTAC) and the current A2ALL ancillary Safety Study. However, to effectively improve patient safety in organ transplantation, the development of a process for reporting of preventable errors that affords protection and the support of empiric research is critical. Further, the transplant community needs to embrace the implementation of evidence-based system and process improvements that will mitigate existing safety vulnerabilities.

Application of the research electronic data capture (REDCap) system in a low- and middle income country- experiences, lessons, and challenges.

The challenges of reliably collecting, storing, organizing, and analyzing research data are critical in low- and middle-income countries (LMICs), particularly in Sub-Saharan Africa where several healthcare and biomedical research organizations have limited data infrastructure. The Research Electronic Data Capture (REDCap) System has been widely used by many institutions and hospitals in the USA for data collection, entry, and management and could help solve this problem. This study reports on the experiences, challenges, and lessons learned from establishing and applying REDCap for a large US-Nigeria research partnership that includes two sites in Nigeria, (the College of Medicine of the University of Lagos (CMUL) and Jos University Teaching Hospital (JUTH)) and Northwestern University (NU) in Chicago, Illinois in the United States. The largest challenges to this implementation were significant technical obstacles: the lack of REDCap-trained personnel, transient electrical power supply, and slow/intermittent internet connectivity. However, asynchronous communication and on-site hands-on collaboration between the Nigerian sites and NU led to the successful installation and configuration of REDCap to meet the needs of the Nigerian sites. An example of one lesson learned is the use of Virtual Private Network (VPN) as a solution to poor internet connectivity at one of the sites, and its adoption is underway at the other. Virtual Private Servers (VPS) or shared online hosting were also evaluated and offer alternative solutions. Installing and using REDCap in LMIC institutions for research data management is feasible; however, planning for trained personnel and addressing electrical and internet infrastructural requirements are essential to optimize its use. Building this fundamental research capacity within LMICs across Africa could substantially enhance the potential for more cross-institutional and cross-country collaboration in future research endeavors.

Influence of heritable social status on daily gain and feeding pattern in pigs.

Social genetic relationships among average daily gain (ADG, g) and feeding pattern as daily feed intake (DFI, g), daily feeder occupation time (DOT, min), and daily feeding rate (DFR, g/min) were examined using records of 547 Duroc boars. Single-trait animal models were fitted differently for traits, including or excluding social genetic effects, random or fixed pen effects, with covariates of pen sizes and initial age or weight. Genetic parameters for feeding pattern were estimated by restricted maximum likelihood. Six sets of parameters for ADG based on literature estimates were used due to difficulty in untangling confounded effects. Positive and negative signs of direct-social genetic covariances were interpreted as heritable cooperation and competition, respectively. Dominant and subordinate pigs were classified as pigs with higher direct and social genetic values, respectively. Correlations of estimated breeding values between ADG and DFI, DOT, and DFR were 0.46, 0.04 and 0.29 for dominant pigs. Given heritable cooperation, subordinate pigs tended to increase feed intake (r = 0.36) and eating rate (r = 0.25). Given heritable competition, subordinate pigs fail to compensate for the competition with decreased feed intake (r = -0.53). The slow eating rate (r = -0.31) was considered as a consequence of eating during less busy hour of feeding.

Estimation of genetic parameters of feed intake and daily gain in Durocs using data from electronic swine feeders.

Genetic parameters for daily feed intake (DFI, g/day) and daily gain (DG, g/day) were estimated using records of 1916 Duroc boars from electronic feeder stations. Management was limited and resulted in varied ranges of age and weight on test. Boars were housed in 102 pens, each equipped with one feeder, and allowed ad libitum feeding. Weekly averages of DFI and DG were used due to large variation in daily records. Six traits were defined as DFI and DG during 85-106 (period 1), 107-128 (period 2) and 129-150 days of age (period 3). A six-trait model included age as a linear and a quadratic covariate for DFI and a linear covariate for DG with a fixed effect of year-week-pen and random effects of litter, additive genetic animal and permanent environmental animal. Variance components were estimated by a Bayesian approach using Gibbs sampling algorithm. Estimates of heritability for respective periods were 18%, 12% and 10% for DFI and 21%, 11% and 10% for DG. Genetic correlations between DFI and DG in the same period were 0.70, 0.73 and 0.32 for the respective periods. DFI and DG obtained from automatic feeders can be analysed to reveal variation across testing periods by using weekly averages when many monthly averages are incomplete.

Relationships among calpastatin single nucleotide polymorphisms, calpastatin expression and tenderness in pork longissimus.

Genome scans in the pig have identified a region on chromosome 2 (SSC2) associated with tenderness. Calpastatin is a likely positional candidate gene in this region because of its inhibitory role in the calpain system that is involved in postmortem tenderization. Novel single nucleotide polymorphisms (SNP) in calpastatin were identified and used to genotype a population (n = 1042) of Duroc-Landrace-Yorkshire swine for association with longissimus lumborum slice shear force (SSF) measured at days 7 and 14 postmortem. Three genetic markers residing in the calpastatin gene were significantly associated with SSF (P < 0.0005). Haplotypes constructed from markers in the calpastatin gene were significantly associated with SSF (F-ratio = 3.93; P-value = 0.002). The levels of normalized mRNA expression of calpastatin in the longissimus lumborum of 162 animals also were evaluated by real-time RT-PCR and were associated with the genotype of the most significant marker for SSF (P < 0.02). This evidence suggests that the causative variation alters expression of calpastatin, thus affecting tenderness. In summary, these data provide evidence of several significant, publicly available SNP markers associated with SSF that may be useful to the swine industry for marker assisted selection of animals that have more tender meat.

Urinary tract infection after voiding cystourethrogram.

BACKGROUND: Reported rates of post-procedural urinary tract infection (ppUTI) after voiding cystourethrogram (VCUG) are highly variable (0-42%). OBJECTIVE: This study aimed to determine the risk of ppUTI after cystogram, and evaluate predictors of ppUTI. STUDY DESIGN: A retrospective cohort study of children undergoing VCUG or radionuclide cystogram (henceforth 'cystogram') was conducted. Children with neurogenic bladder who underwent cystogram in the operating room and without follow-up at the study institution were excluded. Incidence of symptomatic ppUTI within 7 days after cystogram was recorded. Predictors of ppUTI were evaluated using univariate statistics. RESULTS: A total of 1108 children (54% female, median age 1.1 years) underwent 1203 cystograms: 51% were on periprocedural antibiotics, 75% had a pre-existing urologic diagnosis (i.e., vesicoureteral reflux (VUR) or hydronephrosis; not UTI alone), and 18% had a clinical UTI within 30 days before cystogram. Of the cystograms, 41% had an abnormal cystogram and findings included VUR (82%), ureterocele (6%), and diverticula (6%). Twelve children had a ppUTI (1.0%; four girls, five uncircumcised boys, three circumcised boys; median age 0.9 years). Factors significantly associated with diagnosis of a ppUTI (Summary fig.) included: pre-existing urologic diagnosis prior to cystogram (12/12, 100% of patients with ppUTI), abnormal cystogram results (11/12, 92%), and use of periprocedural antibiotics (11/12, 92%). All 11 children with an abnormal cystogram had VUR ≥ Grade III. However, among all children with VUR ≥ Grade III, 4% (11/254) had a ppUTI. DISCUSSION: This is the largest study to date that has examined incidence and risk factors for ppUTI after cystogram. The retrospective nature of the study limited capture of some clinical details. This study demonstrated that the risk of ppUTI after a cystogram is very low (1.0% in this cohort). Having a pre-existing urologic diagnosis such as VUR or hydronephrosis was associated with ppUTI; therefore, children with moderate or high-grade VUR on cystogram may be at highest risk. Development of ppUTI after cystogram also highlighted the potential for a delay in diagnosis or oversight of a healthcare-associated infection due to several factors: 1) cystograms may be ordered, performed/interpreted, and followed up by multiple different providers; and 2) such infections are not captured by traditional healthcare-associated infection surveillance strategies. CONCLUSIONS: The risk of ppUTI after a cystogram is very low. Only children with pre-existing urologic diagnoses developed ppUTI in this study. This study's findings suggest that children undergoing a cystogram should not be given peri-procedural antibiotic prophylaxis for the sole purpose of ppUTI prevention.

Identification of quantitative trait Loci for resistance to southern leaf blight and days to anthesis in a maize recombinant inbred line population.

ABSTRACT A recombinant inbred line population derived from a cross between the maize lines NC300 (resistant) and B104 (susceptible) was evaluated for resistance to southern leaf blight (SLB) disease caused by Cochliobolus heterostrophus race O and for days to anthesis in four environments (Clayton, NC, and Tifton, GA, in both 2004 and 2005). Entry mean and average genetic correlations between disease ratings in different environments were high (0.78 to 0.89 and 0.9, respectively) and the overall entry mean heritability for SLB resistance was 0.89. When weighted mean disease ratings were fitted to a model using multiple interval mapping, seven potential quantitative trait loci (QTL) were identified, the two strongest being on chromosomes 3 (bin 3.04) and 9 (bin 9.03-9.04). These QTL explained a combined 80% of the phenotypic variation for SLB resistance. Some time-point-specific SLB resistance QTL were also identified. There was no significant correlation between disease resistance and days to anthesis. Six putative QTL for time to anthesis were identified, none of which coincided with any SLB resistance QTL.

Racial/ethnic differences in self-reported and biologic measures of chronic stress in pregnancy.

OBJECTIVE: Racial differences in chronic maternal stress may contribute to disparities in pregnancy outcomes. The objective is to identify racial and ethnic differences in self-reported and biologic measures of stress between non-Hispanic black (NHB) and non-Hispanic white (NHW) pregnant women. STUDY DESIGN: NHB and NHW pregnant women were enrolled before 23 weeks of gestation in this prospective cohort study. Equal numbers of women were recruited with public vs private insurance in each racial group. Self-reported stress was measured and blood samples collected in the second and third trimesters were analyzed for serum Epstein-Barr virus antibody, C-reactive protein (CRP), corticotropin-releasing hormone (CRH) and adenocorticotropic hormone (ACTH). RESULTS: One hundred and twelve women were enrolled. NHW women reported more buffers against stress (P=0.04) and neighborhood satisfaction (P=0.02). NHB women reported more discrimination (P<0.001), food insecurity (P=0.04) and had significantly higher mean CRP levels and mean ACTH levels in the second and third trimesters. CONCLUSION: Significant differences in self-reported and biologic measures of chronic stress were identified between NHB and NHW pregnant women with similar economic characteristics. Future studies should investigate mechanisms underlying these differences and their relationship to pregnancy outcomes.

Health insurance for low-income working families. Effect on the provision of immunizations to preschool-age children.

BACKGROUND: The out-of-pocket cost for immunizations is a cause for referral to public health department clinics and is associated with delayed immunization. In 1991, New York State started Child Health Plus (CHPlus), an insurance program that covers ambulatory care and immunization services for children of families earning less than 222% of the poverty level. OBJECTIVE: To determine the effect of CHPlus on the provision of immunizations. DESIGN: A before-and-after design was used to compare the year immediately before enrollment in CHPlus with the first year after enrollment in CHPlus. A mixed-model analysis of variance was used to control for the effects of age. SETTING: All area primary care practices (n = 164) and public health department clinics (n = 6). SUBJECTS: Children (n = 1730) younger than 6 years who were enrolled in CHPlus. MAIN OUTCOME MEASURES: Number of immunization visits; types of providers (public health department clinics or primary care providers [pediatricians and family physicians]); and series-complete immunization coverage, including the diphtheria toxoid, tetanus toxoid, and pertussis vaccine, the oral poliovirus vaccine, and the measles, mumps, and rubella vaccine. RESULTS: The average age of the children was 37.7 months, 85% were white, 50% had been uninsured for immunizations before enrollment in CHPlus, and 16% previously received Medicaid. For infants, CHPlus decreased immunization visits to public health department clinics by 37% (from 0.14 to 0.09 visits per child, P = .009), increased immunization visits to primary care providers' offices by 15% (from 2.3 to 2.7 visits per child, P = .001), and increased immunization coverage by 7% (from 76% to 83%, P = .03). For children aged 1 to 5 years, CHPlus decreased visits to public health department clinics by 67% (from 0.06 to 0.02 visits per child, P < .001), increased visits to primary care providers' offices by 27% (from 0.46 to 0.59 visits per child, P < .001), and increased immunization coverage by 5% (from 83% to 88%, P < .001). The effects were greatest among previously uninsured children and among those with a gap in insurance coverage that was longer than 6 months. CONCLUSIONS: Insurance coverage for low-income working families resulted in a shift in the provision of immunizations from the health department to primary care providers and in increased immunization coverage.

Profile of uninsured children in the United States.

OBJECTIVES: To describe the demographic characteristics, utilization of medical services, and health status of uninsured children compared with insured children in the United States and to assess the factors associated with lack of health insurance among children. An estimated 8 million children in the United States are uninsured. Medicaid expansions and tax credits have had little impact on the overall problem. An understanding of the characteristics of uninsured children is essential for the design of appropriate outreach and enrollment strategies, benefit packages, and health care provision arrangements for uninsured children. METHODS: Analysis of the 1988 Child Health Supplement of the National Health Interview Survey. RESULTS: Diverse groups of children in the United States lack health insurance. Residence in the South (odds ratio [OR], 2.3) and West (OR, 1.9. [corrected]) and being poor (OR, 2.2) or nearly poor (OR, 2.1) are independently associated with being uninsured. Substantial differences in both sources of care and utilization of medical services exist between uninsured and insured children. Uninsured children lack usual sources of routine care (OR, 3.1) and sick care (OR, 3.8) and also lack appropriate well-child care (OR, 1.5) compared with insured children. Neither being in fair or poor health nor emergency department use are significant independent predictors of being uninsured among children. Children who have a chronic disease, such as asthma, face difficulties of access to care and utilize substantially fewer outpatient and inpatient services. CONCLUSIONS: Universal health insurance, rather than efforts directed at specific groups, appears to be the only way to provide health insurance for all US children. Uninsured and insured children reveal marked discrepancies in access to and utilization of medical services, including preventive services, but have similar rates of chronic health conditions and limitations of activity. Uninsured children do not appear to form a population that will incur higher mean annual expenditures for medical care compared with insured children.

Surgical management of heart-lung transplantation.

Using cyclosporin A, long-term survival after heart-lung transplantation became possible. The drug blocks the immune system more selectively and leaves the tracheal wound healing unimpaired. Since 1981, 501 clinical cases have been collected by the registry of the International Society for Heart Transplantation. Candidates for heart-lung transplantation reveal signs of irreversible heart and lung diseases that may have been caused by cardiac lesions (valvular diseases, Eisenmenger reaction due to congenital malformations) or by pulmonic disorders (primary pulmonary hypertension, emphysema, fibrosis). The standard surgical procedure, which combines donor and recipient tracheas, right atria, and aortas, makes three anastomoses necessary. Immunosuppressive regimen includes cyclosporin A (blood trough levels of 300 to 500 ng/mL), azathioprine (1 to 2 mg/kg), and rabbit antithymocyte globulin (1 to 4 mg immunoglobulin G/kg). After the first two postoperative weeks, rabbit antithymocyte globulin is replaced by methylprednisolone (0.3 to 0.1 mg/kg; 500 mg are given intravenously after opening the aortic cross-clamp; 3 x 125 mg on postoperative day 1). After heart-lung transplantation an extreme variety of problems may evolve. Early postoperative complications (within the first postoperative month) comprise acute isolated lung rejection, multiorgan failure, and bacterial pneumonia. Diagnosis of acute lung rejection proves difficult; it includes clinical signs, chest radiographic appearances, and cytoimmunological monitoring. Transbronchial lung biopsies are of similar value for precise diagnosis as are endomyocardial specimens after heart transplantation. Late postoperative complications (after 1 postoperative month) comprise viral pneumonia, fungal infection, tuberculosis, and chronic obliterative bronchiolitis.(ABSTRACT TRUNCATED AT 250 WORDS)

Extended cardiopulmonary preservation: University of Wisconsin solution versus Bretschneider's cardioplegic solution.

Application of the University of Wisconsin cold storage solution has rapidly expanded to include medium-term to long-term preservation of virtually all intraabdominal organs. Its use in intrathoracic organ transplantation has also been suggested. We therefore examined the efficacy of the University of Wisconsin solution in a primate allotransplantation model for preservation of hearts, and as a simple single-solution system for static preservation of heart-lung blocks, for periods of ischemia ranging from 6 to 24 hours. For comparison, we employed the histidine-tryptophane-ketoglutarate cardioplegic solution of Bretschneider. University of Wisconsin solution provided superior results with regard to clinical outcome and hemodynamic recovery of hearts after ischemic periods of up to 16 hours. This was in contrast to Bretschneider's solution, which allowed storage of hearts for periods of only up to 10 hours. Heart-lung blocks were equally well preserved with either University of Wisconsin or Bretschneider's solution after 6 to 12 hours, although the University of Wisconsin solution group exhibited a more notable increase in pulmonary water content. This was in accordance with histological data, which suggested that, although hemodynamic recovery of hearts stored for periods longer than 10 hours was poor, preservation of pulmonary ultrastructure was far superior using Bretschneider's solution as compared with University of Wisconsin solution after an ischemic period of up to 16 hours.

Quinidine-like activity of atropine in rabbit atria.

Direct effects of atropine and quinidine on contractile force, overdrive suppression, and effective refractory period was studied in rabbit atria. Left atrial contractile force at normal CaCl2 concentration (2.2 mM) and the contractile force response to elevated CaCl2 (5 mM) were unchanged over 30 min. Atropine exposure (1.7 X 10(-5) M) for 30 min significantly reduced contractile force at both normal and elevated CaCl2 levels. Quinidine exposure (6.2 X 10(-6) M) for 30 min produced similar but statistically insignificant changes. At 4 h, control contractile force at 2.2 mM CaCl2 decreased to the post-atropine level, but the response to 5 mM CaCl2 was unchanged. The asystolic interval of right atria following overdrive (for 2 min at 3 rates) was increased after 30 min by 4% for controls, 14% after atropine (1.7 X 10(-5) M) and 45% after quinidine. The effective refractory period of left atria (evaluated by paired pulse stimulation) was unchanged after 30 min for controls, but increased by 20% after atropine and 45% after quinidine.

Centrally mediated enhancement of ouabain cardiotoxicity by angiotensin II in dogs.

The effect of angiotensin II (Ang II) infusion on the doses of ouabain required to induce ventricular arrhythmias and death was investigated in anesthetized dogs. Tritiated ouabain was infused alone i.v. (1 microgram/kg per min) to establish the control toxic doses and the level of ouabain in the heart at death. When Ang II and ouabain were co-infused i.v. the doses of ouabain needed to induce arrhythmias and death were significantly reduced. Spinal transections performed at C-1 prior to drug infusions prevented the effect of Ang II to enhance the toxicity of ouabain. Thus, the action of Ang II to augment ouabain toxicity appeared to be related to its effects on the sympathetic nervous system. To confirm that Ang II was acting within the brain rather than at peripheral sites of the sympathetic system, Ang II was infused into the vertebral artery of spinal cord intact dogs. The infusion rate of Ang II needed to produce a significant enhancement of ouabain toxicity was much lower when given into the vertebral artery than into the femoral vein. These data indicate that Ang II enhances the cardiotoxicity of ouabain via an action produced within the brain and mediated by the sympathetic nervous system.

Selective additive effect of phenylephrine to the inotropic action of isoproterenol on rabbit left atria.

The chronotropic and inotropic effects of isoproterenol, adrenaline and phenylephrine were examined in isolated right and left rabbit atria. 1. Spontaneous right atrial rate (RAR) and left atrial contractile force (LACF) (electrically stimulated at 2 Hz) were monitored during separate concentration-response curves to all 3 agonists. The order of potency for both parameters was isoproterenol greater than adrenaline greater than phenylephrine. 2. At maximum agonist effect, adrenaline produced the greatest LACF increase, followed in order by isoproterenol and phenylephrine. 3. When phenylephrine (6.0 x 10(-5) M) was added to the left atria maximally stimulated with isoproterenol, an additional 32% increase in LACF was recorded, but an additive effect was not noted when phenylephrine was added to atria maximally stimulated with adrenaline. The LACF achieved by a combination of isoproterenol and phenylephrine approximated the maximum LACF induced by adrenaline alone. 4. At maximum agonist effect, isoproterenol and adrenaline produced a greater RAR increase than phenylephrine. Further, phenylephrine did not increase the maximum RAR effect of isoproterenol or adrenaline. 5. Adrenergically mediated chronotropic increases appear to be mediated by a beta adrenoceptor and the maximum response to agonists of full intrinsic activity can not be further increased by agonist combinations. However inotropic increases appear to be mediated by 2 adrenoceptor types which may be simultaneously stimulated to produce additive effects. The two adrenoceptors mediating inotropic change are probably alpha and beta.

Do market-level hospital and physician resources affect small area variation in hospital use?

This study evaluates the effect of market-level physician and hospital resources on hospital use. It is anticipated that higher hospital discharges are associated with (1) greater hospital and physician resources, (2) more differentiated hospital and physician resources, and (3) higher levels of teaching intensity in the community. Data on 14 modified diagnostically related groups (DRGs) and 58 hospital market communities in Michigan are analyzed during a 7-year period. Findings indicate that physician resources, hospital resources, differentiation of hospital and physician resources, and teaching intensity contribute only modestly to discharges, holding constant the socioeconomic attributes of the community and adjusting for the variation in hospital use over time. With the inclusion of hospital and physician resource variables, socioeconomic factors remain important determinants of the variation across market communities. Findings are discussed in terms of their implications for health care organizations, managed care programs, and cost control efforts in general.

The impact of market and organizational characteristics on nursing care facility service innovation: a resource dependency perspective.

OBJECTIVE: Using resource dependency theory as a conceptual framework, this study investigates both the organizational and environmental factors associated with an emerging health care service delivery innovation, the provision of specialty care in designated units in nursing care facilities. We consider two types of specialty units, Alzheimer's Disease and subacute care. DATA SOURCES: The Medicare/Medicaid Automated Certification Survey (MMACS) data file was merged with local market area data obtained from the 1992 Area Resource File and with state level regulatory data. STUDY DESIGN: The likelihood of providing Alzheimer's Disease or subacute care in dedicated units was estimated by separate logistic regressions. PRINCIPAL FINDINGS: Results indicate that facilities with fewer Medicare patients are more likely to operate a dedicated Alzheimer's care unit, while facilities located in markets with a large HMO population and greater hospital supply are more likely to operate a subacute care unit. While competition among nursing homes, for the most part, is an incentive to innovate, greater regulatory stringency appears to constrain the development of specialty care units of both types. Finally, organizational characteristics (e.g., size and proprietary status) appear to be important enabling factors influencing the propensity to provide specialty care in dedicated units. CONCLUSIONS: Nursing care facilities are moving toward providing specialty care units partly as a response to a growing demand by resource providers and to maintain a competitive edge in tighter markets. Loosening regulation directed at cost containment would further encourage the development of specialty care but should be preceded by some evaluation of population needs for specialty care and the effectiveness of specialty care units.