Effect of a peripheral NMDA receptor antagonist on glutamate-evoked masseter muscle pain and mechanical sensitization in women

AIMS: To test the hypothesis that local injection of the N-methyl-D-aspartate (NMDA) receptor antagonist ketamine would significantly attenuate glutamate-evoked masseter mechanical sensitization and muscle pain in healthy young women either taking oral contraceptives (W+OC) or not taking oral contraceptives (W-OC). METHODS: Experimental pain was evoked in 47 healthy female subjects (W+OC, n=25; W-OC, n=22) by 2 injections of glutamate (0.2 mL, 1 mol/L) into the masseter muscle. A first injection of glutamate alone was followed by a second injection, 35 minutes later, of glutamate combined with ketamine (0, 1, or 10 mmol/L). Evoked pain intensity was scored on a 10-cm electronic visual analog scale (VAS). Distribution of perceived pain was drawn on a lateral view of the face (pain drawing). Masseter muscle pressure pain thresholds (PPT) and pressure-pain tolerances (PPTOL) were determined bilaterally before and at regular time intervals after injections. Analyses of variance (ANOVA) were used to test the data. RESULTS: There were no main effects of ketamine on any of the VAS pain parameters or on the pain drawing (ANOVAs: P > .055). Furthermore, there were no differences in PPT, PPTOL, VAS peak pain, duration, overall VAS pain, or pain drawing when W-OC were compared with W+OC (ANOVAs: P > .087). Repeated injection of glutamate alone significantly decreased PPT and PPTOL (ANOVAs: P < .001); however, this effect was not significantly attenuated by ketamine. CONCLUSIONS: Peripherally administered ketamine had no effect on glutamate-evoked masseter muscle pain and sensitization in healthy young women, which contrasts with recent observations in healthy young men. Further studies will be needed to reveal the mechanisms that underlie this apparent sex-related difference in ketamine-mediated analgesia.     

Human modification of global water vapor flows from the land surface

It is well documented that human modification of the hydrological cycle has profoundly affected the flow of liquid water across the Earth's land surface. Alteration of water vapor flows through land-use changes has received comparatively less attention, despite compelling evidence that such alteration can influence the functioning of the Earth System. We show that deforestation is as large a driving force as irrigation in terms of changes in the hydrological cycle. Deforestation has decreased global vapor flows from land by 4% (3,000 km(3)/yr), a decrease that is quantitatively as large as the increased vapor flow caused by irrigation (2,600 km(3)/yr). Although the net change in global vapor flows is close to zero, the spatial distributions of deforestation and irrigation are different, leading to major regional transformations of vapor-flow patterns. We analyze these changes in the light of future land-use-change projections that suggest widespread deforestation in sub-Saharan Africa and intensification of agricultural production in the Asian monsoon region. Furthermore, significant modification of vapor flows in the lands around the Indian Ocean basin will increase the risk for changes in the behavior of the Asian monsoon system. This analysis suggests that the need to increase food production in one region may affect the capability to increase food production in another. At the scale of the Earth as a whole, our results emphasize the need for climate models to take land-use change, in both land cover and irrigation, into account.     

Anorectal function after modern conformal radiation therapy for prostate cancer: a pilot study

We evaluated whether, and if so to what extent, radiotherapy applied on a series of patients with prostate cancer influenced the patient's bowel habits and anorectal function. Ten consecutive patients participated in the study. The median age of the patients was 74 years (range, 61–71) and the average follow-up period was 22 (range, 15–28) months. Four patients were irradiated using external beam radiotherapy (2 Gy/day for a total of 70 Gy); 6 patients were irradiated with a combination of external beam radiotherapy (50 Gy, 2 Gy/day) and high dose rate brachytherapy (two 10-Gy fractions). Upon interview, patients disclosed characteristic functiona disturbances such as urgency with occasional accidents, faecal soiling and spotting of underwear. Involuntary release of gas was another embarrassing problem. One or more of these problems were present in half of the patients. Endoscopy disclosed signs of mild proctitis. Sphincter pressure, rectal capacity and the volume threshold for appreciation of defecation urge were all significantly lower in patients than in 10 age-matched controls. In conclusion, disturbances of anorectal function with imperfection of incontinence still occur so some extent despite improved precision, and reduced margins offered by the modern conformal radiation therapy of prostate cancer. Anal sphincter function, the reservoir capacity of the rectum and its sensory function are adversely affected and radiation proctitis with rectal fibrosis and damage of the extrinsic innervations of the anal sphincters appear to be the principal causative factors. Although conformal radiotherapy together with better positioning may be two substantial improvements of modern radiotherapy, further improvements are needed. Received: 11 May 2002 / Accepted: 12 June 2002 Correspondence to L. Hultén     

The Building Blocks Collaborative: Advancing a Life Course Approach to Health Equity Through Multi-Sector Collaboration

Too many children are born into poverty, often living in disinvested communities without adequate opportunities to be healthy and thrive. Two complementary frameworks—health equity and life course—propose new approaches to these challenges. Health equity strategies seek to improve community conditions that influence health. The life course perspective focuses on key developmental periods that can shift a person’s trajectory over the life course, and highlights the importance of ensuring that children have supports in place that set them up for long-term success and health. Applying these frameworks, the Alameda County Public Health Department launched the Building Blocks Collaborative (BBC), a countywide multi-sector initiative to engage community partners in improving neighborhood conditions in low-income communities, with a focus on young children. A broad cross-section of stakeholders, called to action by the state of racial and economic inequities in children’s health, came together to launch the BBC and develop a Bill of Rights that highlights the diverse factors that contribute to children’s health. BBC partners then began working together to improve community conditions by learning and sharing ideas and strategies, and incubating new collaborative projects. Supportive health department leadership; dedicated staff; shared vision and ownership; a flexible partnership structure; and broad collective goals that build on partners’ strengths and priorities have been critical to the growth of the BBC. Next steps include institutionalizing BBC projects into existing infrastructure, ongoing partner engagement, and continued project innovation—to achieve a common vision that all babies have the best start in life.