High levels of estradiol impair spatial performance in the Morris water maze and increase 'depressive-like' behaviors in the female meadow vole

The present study investigated sex differences and the effect of a high level of estradiol in the female meadow vole on performance in the forced swim test (FST) and the Morris water maze in meadow voles. Female meadow voles were ovariectomized (OVX) and administered either vehicle (sesame oil) or estradiol for 2 days prior to performing the FST. Four days following the FST, all animals were run in the Morris water maze. Results indicated that estradiol-injected female meadow voles showed more 'depressive-like' behaviors in the FST (greater time spent immobile and less time spent swimming) than vehicle-treated female or male meadow voles. In addition, estradiol-treated females had impaired performance (greater latencies and distance swam to reach the hidden platform) than both vehicle-treated female and male meadow voles, consistent with previous data. Despite the fact that estradiol administration increased 'depressive-like' behaviors in the FST and impaired performance in the Morris water maze, there was no correlation between the two behaviors indicating that 'depressive-like' behaviors did not account for the differences seen in spatial performance in the Morris water maze. To our knowledge, this is the first demonstration in rodents indicating that estradiol-mediated changes in behavior in the FST is not indicative of subsequent performance in the Morris water maze.     

Gender Variance in Children and Adolescents with Neurodevelopmental and Psychiatric Conditions from Australia

Archives of Sexual Behavior - Gender variance is a broad term used to describe gender non-conforming behaviors. Past studies have used the parental response to Child Behavior Checklist (CBCL) Item...     

Short-term associations between emergency hospital admissions for respiratory and cardiovascular disease and outdoor air pollution in London

There are concerns about the possible short-term effects of outdoor air pollution on health in the United Kingdom. In a study conducted during the time period between 1987 and 1992, investigators determined that ozone had small, but significant effects on emergency respiratory admissions. In the current study, the authors investigated associations between emergency admissions and outdoor air pollution for the time period from 1992 to 1994, inclusive, and compared the results with those obtained in the earlier study. The authors also examined particulate matter less than 10 microm in diameter (PM10) and carbon monoxide in the current study. Appropriate confounding factors, such as seasonal patterns, temperature, and humidity, were controlled for, and the authors used Poisson regression to estimate the association between daily emergency admissions for respiratory and cardiovascular diseases and ozone, nitrogen dioxide, sulfur dioxide, carbon monoxide, particles measured as Black Smoke, and PM10. Significant positive associations were found between emergency hospital admissions for respiratory disease and PM10 and sulfur dioxide, but such an association did not exist for ozone. The results were not significantly different from earlier results from London and were comparable with those determined in North America and Europe. Cardiovascular disease was associated with carbon monoxide and Black Smoke, but weaker associations existed with the other pollutants studied.     

Factors influencing the emigration of physicians from Canada to the United States.

OBJECTIVE: To determine whether location of postgraduate medical training and other factors are associated with the emigration of physicians from Canada to the United States. DESIGN: Case-control study, physicians were surveyed with the use of a questionnaire mailed in May 1994 (with a reminder sent in September 1994), responses to which were accepted until Dec. 31, 1994. PARTICIPANTS: Physicians randomly selected from the CMA database, 4000 with addresses in Canada and 4000 with current addresses in the United States and previous addresses in Canada. OUTCOME MEASURES: Sex, age, location of undergraduate and postgraduate medical training, qualifications, practice location, opinions concerning residence decisions, current satisfaction and plans. RESULTS: The overall response rate was 49.6% (50.0% among physicians in the United States and 49.2% among those in Canada). Age and sex distributions were similar among the 8000 questionnaire recipients and the nearly 4000 respondents. Physicians living in the United States were more likely to be older (mean 53.2 v. 49.6 years of age), male (87% v. 75%) and specialists (79% v. 52%) than those practising in Canada. Postgraduate training in the United States was associated with subsequent emigration (odds ratio 9.2, 95% confidence interval 7.8 to 10.7). However, in rating the importance of nine factors in the decision to emigrate or remain in Canada, there was no significant difference between the two groups in the rating assigned to location of postgraduate training. Professional factors rated most important by most physicians in both groups were professional/clinical autonomy, availability of medical facilities and job availability. Remuneration was considered an equally important factor by those in Canada and in the United States. Six of seven personal/family factors were rated as more important to their choice of practice location by respondents in Canada than by those in the United States. Current satisfaction was significantly higher among respondents in the United States. Most physicians in each group planned to continue practising at their current location. Of Canadian respondents, 22% indicated that they were more likely to move to the United States than they were a year beforehand, whereas 4% of US respondents indicated that they were more likely to return to Canada. CONCLUSIONS: Factors affecting the decision to move to the United States or remain in Canada can be categorized as "push" factors (e.g., government involvement) and "pull" factors (e.g., better geographic climate in the US). Factors can also be categorized by whether they are amenable to change (e.g., availability of medical facilities) or cannot be managed (e.g., proximity of relatives). An understanding of the reasons why physicians immigrate to the United States or remain in Canada is essential to planning physician resources nationally.     

Improvement in function after valgus bracing of the knee. An analysis of gait symmetry

The use of a valgus brace can effectively relieve the symptoms of unicompartmental osteoarthritis of the knee. This study provides an objective measurement of function by analysis of gait symmetry. This was measured in 30 patients on four separate occasions: immediately before and after initial fitting and then again at three months with the brace on and off. All patients reported immediate symptomatic improvement with less pain on walking. After fitting the brace, symmetry indices of stance and the swing phase of gait showed a consistent and immediate improvement at 0 and 3 months, respectively, of 3.92% (p = 0.030) and 3.40% (p = 0.025) in the stance phase and 11.78% (p = 0.020) and 9.58% (p = 0.005) in the swing phase. This was confirmed by a significant improvement at three months in the mean Hospital for Special Surgery (HSS) knee score from 69.9 to 82.0 (p < 0.001). Thus, wearing a valgus brace gives a significant and immediate improvement in the function of patients with unicompartmental osteoarthritis of the knee, as measured by analysis of gait symmetry.     

Epidemiology of pneumothorax in England

BACKGROUND: Little is known of the epidemiology of pneumothorax. Routinely available data on pneumothorax in England are described. METHODS: Patients consulting in primary care with a diagnosis of pneumothorax in each year from 1991 to 1995 inclusive were identified from the General Practice Research Database (GPRD). Emergency hospital admissions for pneumothorax were identified for the years 1991-4 from the Hospital Episode Statistics (HES) data. Mortality data for England & Wales were obtained for 1950-97. Analyses of pneumothorax rates by age and sex were performed for all data sources. Seasonal and geographical analyses were carried out for the HES data. RESULTS: The overall person consulting rate for pneumothorax (primary and secondary combined) in the GPRD was 24. 0/100 000 each year for men and 9.8/100 000 each year for women. Hospital admissions for pneumothorax as a primary diagnosis occurred at an overall incidence of 16.7/100 000 per year and 5.8/100 000 per year for men and women, respectively. Mortality rates were 1. 26/million per year for men and 0.62/million per year for women. The age distribution in both men and women showed a biphasic distribution for both GP consultations and hospital admissions. Deaths showed a single peak with highest rates in the elderly. There was an urban-rural trend observed for hospital admissions in the older age group (55+ years) with admission rates in the conurbations significantly higher than in the rural areas. Analysis for trends in mortality data for 1950-97 showed a striking increase in the death rate for pneumothorax in those aged 55+ years between 1960 and 1990, with a steep decline in the 1990s. Mortality in the younger age group (15-34 years) remained low and constant. CONCLUSION: There is evidence of two epidemiologically distinct forms of spontaneous pneumothorax in England. The explanation for the rise and fall in mortality for secondary pneumothorax is obscure.     

The selective serotonin-2A receptor antagonist M100907 reverses behavioral deficits in dopamine transporter knockout mice.

A hyperdopaminergic state in humans has been hypothesized to contribute to the pathology of a number of psychiatric illnesses, including schizophrenia, bipolar disorder, and attention deficit hyperactivity disorder. Mice that display elevated synaptic levels of dopamine due to a genetically engineered deletion of the dopamine transporter (DAT) model behavioral deficits that simulate the above conditions. As novel treatment strategies for these disorders have focused on the serotonin (5-HT) 2A receptor, we determined the capacity of the highly selective 5-HT(2A) receptor antagonist M100907 to reverse behavioral deficits in DAT knockout (KO) mice. Prior to drug treatment, DAT KO mice exhibited increased levels of locomotor activity and highly linearized movement in a novel environment, as well as reduced prepulse inhibition (PPI) of acoustic startle, compared to wild-type littermates. Treatment with M100907 (0.3-1.0 mg/kg, but not 0.1 mg/kg) reversed locomotor deficits in DAT KO mice. Similarly, treatment with 1.0 mg/kg M100907 reversed the PPI deficits in DAT KO mice. These data indicate that selective 5-HT(2A) receptor antagonists, such as M100907, may represent a class of drugs that can be used to treat conditions in which a chronic, elevated dopaminergic tone is present and contributes to abnormal behavior and sensorimotor gating deficits.