Effect of menstrual cycle phase on dopamine D2 receptor availability in female cynomolgus monkeys

Sex differences have been reported in a variety of affective and neurodegenerative disorders that involve dysfunctional dopamine (DA) neurotransmission. In addition, there is evidence for differences in sensitivity to the abuse-related effects of psychostimulants across the menstrual cycle which may result from effects of ovarian hormones on DA function. The goal of the present study was to extend previous work examining menstrual cycle-related changes in DA D2 receptor availability in humans to drug-naive female cynomolgus monkeys (n=7) using the selective D2-like receptor ligand [(18)F]fluoroclebopride (FCP) and a high-resolution microPET P4 scanner. Menstrual cycle phase was characterized by daily vaginal swabs and measurements of serum progesterone levels. PET studies were conducted once during the luteal phase and once during the follicular phase. Regions of interest in the caudate nucleus, putamen, and cerebellum were defined on coregistered MRIs. Distribution volumes were calculated for FCP in each structure and the distribution volume ratio (DVR) for both brain regions relative to the cerebellum was used as a measure of D2 receptor availability. FCP DVRs were significantly higher in the luteal phase compared to the follicular phase in both the caudate nucleus (11.7% difference, p=0.02) and putamen (11.6% difference, p=0.03). These findings extend earlier work in humans and suggest that changes in DA receptor availability may be involved in the variation in symptoms of various neuropsychiatric disorders across the menstrual cycle, including differences in sensitivity to the abuse-related effects of stimulants.     

Disparities in colon cancer screening in the Medicare population

BACKGROUND: Colorectal cancer is the third most common cancer in the United States, but the rate of screening remains low. Since 2001, Medicare has provided coverage of colonoscopy for colorectal cancer screening in individuals at average risk, but little is known about the effect of this coverage on screening or disparities in screening practices. METHODS: We examined the Medicare physician/supplier billing claims file for New York, Florida, and Illinois for the years 2002 and 2003. Using a previously employed algorithm, we identified the rates of colorectal screening tests in individuals at average risk. We performed multivariate logistic regression analysis to calculate the effects of sex, racial/ethnic, and socioeconomic characteristics on screening. We also looked for interactions between socioeconomic and demographic variables. RESULTS: A total of 596 470 Medicare beneficiaries were included in the study. Approximately 18.3% of the population had undergone a screening colon test during the study period. Nonwhite persons were less likely to be screened for colorectal cancer than were white persons (relative risk [RR], 0.52; 95% confidence interval [CI], 0.50-0.53). The lowest RR of screening colonoscopy in women compared with men was in the oldest age group and the highest income tertile (RR for whites, 0.64; 95% CI, 0.59-0.70). Higher income level was associated with screening colonoscopy in white patients (men: RR, 1.19; 95% CI, 1.14-1.25; women: RR, 1.09; 95% CI, 1.05-1.15) but not in nonwhite patients (men: RR, 0.97; 95% CI, 0.78-1.22; women: RR, 0.94; 95% CI, 0.78-1.14). CONCLUSION: Despite the expansion of Medicare coverage for colorectal cancer screening, there still remain significant disparities between sex and racial/ethnic groups in screening practices.     

Exploring the surgeon volume outcome relationship among women with breast cancer

BACKGROUND: A relationship between higher surgeon volume and lower mortality has been described for breast cancer, but selection bias has not been rigorously evaluated. We studied potential bias in the surgeon volume-outcome relationship by comparing the relationship of surgeon volume to breast cancer mortality and to mortality from other causes of death. METHODS: We conducted an observational cohort study from tumor registry and Medicare claims data on 12 216 women, 66 years or older, with stage I or II breast cancer, who were operated on by 1856 surgeons. Breast cancer mortality and other-cause mortality were determined from death certificate sources and surgeon volume from Medicare claims. RESULTS: Treatment by a high-volume surgeon was associated with younger patient age, white race, less comorbidity, and residence in a more affluent zip code. Patients treated by low-, medium-, and high-volume surgeons had small differences in breast cancer mortality (17.4, 15.7, and 13.0 deaths per 1000 person-years, respectively; P = .03) but larger differences in non-breast cancer mortality (46.0, 36.8, and 31.7 deaths per 1000 person-years, respectively; P < .001). After adjustment for multiple patient and disease factors, women treated by high-volume surgeons, compared with those treated by low-volume surgeons, were not less likely to die of breast cancer (relative risk, 0.94; 95% confidence interval, 0.76-1.16) but were significantly less likely to die of other causes (relative risk, 0.86; 95% confidence interval, 0.75-0.98). CONCLUSIONS: The surgeon volume-outcome relationship for these patients with breast cancer was attributable not to mortality from breast cancer but to other causes of death. The lack of specificity of this relationship raises the possibility of selection bias as an explanatory factor.     

Cutaneous phenotype and MC1R variants as modifying factors for the development of melanoma in CDKN2A G101W mutation carriers from 4 countries

The G101W founder mutation is the most common CDKN2A mutation in Italy, Spain, and France. As the background of modifying genes, environmental exposures, and sun behavior vary across countries, studying G101W carriers from distinct countries offers a unique opportunity to evaluate possible modifying factors in melanoma development. We evaluated 76 G101W cases and 59 carrier controls from France, Italy, Spain, and the United States. Hair color and dysplastic nevi distributions differed significantly in cases and controls across the 4 study groups. Cases also varied significantly for eye color, freckling, and nevi. The distribution of MC1R variants in cases differed significantly across study groups because 12% of Italian melanoma patients had > or =2 MC1R variants vs. >50% for the other case groups. Several MC1R covariates showed significant associations with melanoma risk in all groups combined and in the American, French, and Spanish samples; no significant findings were observed in the Italian sample. In multiple-case families, the number and type of MC1R variants varied significantly between multiple-primary-melanoma and single-primary-melanoma patients from the 4 groups; there was also a significant decrease in median age at melanoma diagnosis as the number or type of MC1R variants increased. The variation in the effects of the cutaneous phenotypic and MC1R factors across the study sample suggests that these factors differentially contribute to development of melanoma even on a common genetic background of a germline CDKN2A mutation. Differences in melanoma risk across geographic regions justify the need for individual studies in each country before counseling should be considered.     

Perceived accessibility versus actual physical accessibility of healthcare facilities.

This study addressed how healthcare clinics perceive themselves in regard to accessibility for persons with spinal cord injuries (SCI). All 40 of the clinics surveyed reported that they were wheelchair accessible; however, there was significant variability in the number of sites that actually met the guidelines of the Americans with Disability Act. In general, a person using a wheelchair could enter the building, the examination room, and the bathroom. The majority of sites did not have an examination table that could be lowered to wheelchair level. Most reported limited experience in working with persons with (SCI), yet they claimed to be able to assist with difficult transfers. Only one site knew about autonomic dysreflexia. Problems of accessibility appeared to be seriously compounded by the clinics' perception of how they met physical accessibility guidelines without consideration of the actual needs of persons with SCI. This study addressed the perception of accessibility as reported by clinic managers versus actual accessibility in healthcare clinics in a Midwestern metropolitan area for persons using wheelchairs.     

Challenging behaviors should not be considered depressive equivalents in individuals with intellectual disabilities. II. A replication study

Previous research has proposed behavioral equivalents for depression, but evidence for behavioral equivalents has been contradictory. The relationship between a measure of depression and several proposed behavioral equivalents of depression was assessed in 693 adults living in a large residential setting. Most were adults with severe or profound intellectual disability. The frequency of language-based measures of depression was very low. A scale to assess depression was constructed based on an item analysis of a larger pool of items. Both item and factor analysis and correlations between scores on the depression scale and individual maladaptive behavior items showed little or no relationship between proposed behavioral equivalents and depression. No support was found for behavioral equivalents of depression. This replicated the findings of Tsiouris, Mann, Patti, and Sturmey (2003). Practitioners are cautioned against using maladaptive behaviors as evidence of depression in people with severe or profound intellectual disabilities.     

Paediatric use of intensive care

OBJECTIVES--To determine the number of children from a defined population who use intensive care facilities, to analyse bed occupancy data for those children, and to estimate the number of intensive care beds required to satisfy this demand throughout the year. DESIGN--Examination of admission data books from intensive care units within the four Birmingham health authorities and the neighbouring health authorities. RESULTS--Two hundred and ninety seven children resident within the four Birmingham health authorities used intensive care facilities in a calendar year. One hundred and forty one (47%) of these were admitted for specialist paediatric services. Of the remaining 156, 106 (68%) were cared for in adult intensive care units, 46 (29%) in a paediatric intensive care unit and four (3%) in a special care baby unit. Use of intensive care varied from none to 11 patients each day, and was lowest in the summer and highest during the winter months. During periods of peak demand, one in 19,000 (5.3/100,000) children were using intensive care facilities. CONCLUSIONS--These data provide a population based minimum need for paediatric intensive care beds. They are higher than previous estimates and do not include provision for children from outside Birmingham, or for those denied intensive care due to bed shortages. These factors and the marked seasonal variation in demand need to be considered when planning intensive care services for children if bed shortages are to be avoided.     

Decreased deformability of erythrocytes from smokers

The deformability of erythrocytes from smoking and non-smoking human subjects was examined by filtration through 3-mu pores and capillary viscometry of cell suspensions. In both cases, small but significant differences were found between the two groups that are consistent with a reduction in the surface area-to-volume ratio and/or a diminished membrane flexibility in erythrocyte from smokers. Additional evidence suggests that these findings represent a chronic rather than an acute effect of smoking on erythrocyte deformability.     

Thirty-day readmissions after elective spine surgery for degenerative conditions among US Medicare beneficiaries

Background context

Readmissions within 30 days of hospital discharge are undesirable and costly. Little is known about reasons for and predictors of readmissions after elective spine surgery to help plan preventative strategies.

Purpose

To examine readmissions within 30 days of hospital discharge, reasons for readmission, and predictors of readmission among patients undergoing elective cervical and lumbar spine surgery for degenerative conditions.

Study design

Retrospective cohort study.

Patient sample

Patient sample includes 343,068 Medicare beneficiaries who underwent cervical and lumbar spine surgery for degenerative conditions from 2003 to 2007.

Outcome measures

Readmissions within 30 days of discharge, excluding readmissions for rehabilitation.

Methods

Patients were identified in Medicare claims data using validated algorithms. Reasons for readmission were classified into clinically meaningful categories using a standardized coding system (Clinical Classification Software).

Results

Thirty-day readmissions were 7.9% after cervical surgery and 7.3% after lumbar surgery. There was no dominant reason for readmissions. The most common reasons for readmissions were complications of surgery (26%–33%) and musculoskeletal conditions in the same area of the operation (15%). Significant predictors of readmission for both operations included older age, greater comorbidity, dual eligibility for Medicare/Medicaid, and greater number of fused levels. For cervical spine readmissions, additional risk factors were male sex, a diagnosis of myelopathy, and a posterior or combined anterior/posterior surgical approach; for lumbar spine readmissions, additional risk factors were black race, Middle Atlantic geographic region, fusion surgery, and an anterior surgical approach. Our model explained more than 60% of the variability in readmissions.

Conclusions

Among Medicare beneficiaries, 30-day readmissions after elective spine surgery for degenerative conditions represent a target for improvement. Both patient factors and operative techniques are associated with readmissions. Interventions to minimize readmissions should be specific to surgical site and focus on high-risk subgroups where clinical trials of interventions may be of greatest benefit.