Aging cartilage and osteoarthritis--what's the link?

Cartilage aging can contribute to the development of osteoarthritis (OA), the most common cause of chronic pain and disability in older adults. Articular cartilage is a unique tissue from the perspective of aging in that the cells (chondrocytes) and the majority of the extracellular matrix proteins experience little turnover, resulting in a tissue that must withstand years of use and can also accumulate years of aging-associated changes. Accumulation of advanced glycation end products (AGEs) occurs in cartilage, and the potential role of AGEs in the development of OA is being investigated. An age-associated reduction in growth factor signaling and an increase in oxidative stress may also play an important role in the age-OA connection. Further elucidation of mechanisms that affect chondrocyte function with aging should lead to novel interventions designed to slow the aging process in cartilage with the goal of preventing age-associated OA.     

Sexual behavior among HIV-positive men who have sex with men: what's in a label?

Relatively little attention has been paid to the use and importance of labels used by men who have sex with men to describe insertive or receptive sexual behavior during intercourse. This study examines sexual self-labels, sexual behavior, HIV transmission risk, and psychological functioning among 205 HIV-seropositive men who have sex with men. The majority of participants (88%) identified as a top, a bottom, or versatile. Tops were more likely to engage in insertive anal intercourse than bottoms, and bottoms were more likely to engage in receptive anal intercourse than tops, with versatiles reporting intermediate rates of both behaviors. Although the results suggest preliminary evidence regarding the predictive utility of self-labels, sexual behaviors of self-label groups were greatly overlapping. Differences were found among self-label groups in gay self-identification, internalized homophobia, sexual sensation seeking, and anxiety. Results suggest an added value in assessing self-labels in addition to asking about sexual behavior.     

Money management,patient safety and customer service among top concerns for physician executives. Interview by Barbara Linney

Find out what's happening today and what the future may be like for physician executives. Seasoned physician executives and well-known physician executive recruiters share their insights on the profession.     

Support for Waste Facility Siting: Differences between Community Leaders and Residents

Abstract Decisions regarding hazardous waste facility siting are now open to extensive public debate. Efforts on the part of public officials and private companies to site waste management facilities have been thwarted by public opposition. Using survey data from leaders and residents in communities which are hosting or siting facilities, this study examines their sociodemographic characteristics, knowledge, levels of trust, perceptions of risk, perceptions of economic impacts, perceptions of equity issues and the differential effects of these factors on acceptance of local waste facility siting. Leaders in these communities were more supportive of local waste facility siting than were other community residents. The major determinant of leaders' acceptance of waste siting was their perceptions of the economic benefits of a facility to the community. Although this was also important to residents, perceptions of health, safety, and environmental contamination risks had larger effects on their acceptance of such facilities.     

Self-Concept of Academic Ability and the Adult College Student

Adults' self-concept of academic ability is discussed within the larger context of self-concept theory, the presence of adults in college, and the sparse research on adult self-concept. The operation of adult self-concept was explored with data gathered from 480 undergraduate students age 25 or older. Adult self-concept of academic ability appeared to operate much as predicted by the theory. It was shaped from past academic activities (credits earned and GPA), and it affected subjective academic outcomes such as "how well one feels he/she is doing in college" and "whether one's goals are being met by the college experience." It also affected objective outcomes such as current credit load carried and grades attained. Self-concept did not vary by race, gender, or income, though it did vary by age. Subdomains of self-concept were explored, and the most important appeared to be interaction skills within the classroom. Relating academic self-concept to other psychological variables showed that it is unrelated to motivation, positively related to global self-esteem, and negatively related to depression, stress, and external attributions for academic success.     

Managing strategic change in a mature business

The article draws on the experience of four sectors of the U.K. economy to suggest what the competetive conditions of the next decade might look like. The distinction is made between barries to entry and barries to success. Strategic management in the more successful companies appears to involve the common ability to sustain strategic flexibility. The majority of the piece indicates how this quality has been fashioned and how the process of its creation and maintenance has been managed in the companies concerned. Evidence from the four sectors is used to speculate on some of the key determinants of strategic flexibility in the 1990s.     

Use of Acute Toxicity to Estimate Carcinogenic Risk

Data on the effects of human exposure to carcinogens are limited, so that estimation of the risks of carcinogens must be obtained indirectly. Current risk estimates are generally based on lifetime animal bioassays which are expensive and which take more than two years to complete. We here show how data on acute toxicity can be used to make a preliminary estimate of carcinogenic risk and give an idea of the uncertainty in that risk estimate. The estimates obtained are biased upwards, and so are useful for setting interim standards and determining whether further study is worthwhile. A general scheme which incorporates the use of such estimates is outlined, and it is shown by example how adoption of the procedures suggested could have prevented regulatory hiatus in the past.     

Revolutionary Mexico and the world economy

Conclusion Obregón and Calles encountered intense but disunited resistance at home and abroad. They responded with land and labor reforms to coopt campesinos and urban workers, thereby undercutting popular opposition and enlisting the masses in the campaign against regionalist bosses, Porfirian oligarchs, and foreign investors. These populist alliances helped the Sonoran diarchy build more loyal and professional military and civilian bureaucracies, which in turn helped regulate local and metropolitan firms, increase and stabilize tax revenues, and develop the economy's infrastructure. Following Obregón assasination in 1928, Calles forestalled collapse by integrating many military and civilian bosses into a central party organization. Yet the state remained only partially consolidated. At the end of the Calles administration, regionalist cliques retained considerable political autonomy, and a major campesino rebellion challenged federal authority. Furthermore, dependence on foreign petroleum and mining companies limited government revenue and spending. In mid-1927, Calles inaugurated several years of conservative domestic policies and open collaboration with North Americans. But Calles did not purge all progressive elements from the state machinery. His quest for political stability led him to enroll in the official party many elites who depended on mass followings and who opposed the rightward shift of government policy. During the Great Depression, these elites formed a coalition with intellectuals, small business, and the lower classes that after electing Lázaro Cardenas president, ended Callista hegemony and undertook far-reaching reforms. Thus the Cardenistas completed what Obregón and Calles had begun: the Mexican state's transformation from the poorly centralized oligarchic structure of the Porfiriato to the highly centralized, mass-inclusionary structure of the postrevolutionary era. In the next decade, Mexico joined the ranks of the world's intermediate, semiperipheral economies thanks to import-substitution and metropolitan capital. Since then, Mexican governments have maintained political stability and spurred industrialization by steering a pragmatic course between reformism and conservatism, nationalism and collaborationism.In regard to future research, this essay suggests that we consider not only Mexico's relationship to North Atlantic powers in the 1920s but also its standing vis-à-vis the states and classes of other late-industrializing countries. One possibility is to study the interplay of metropolitan actions to control the raw materials and markets of the periphery with the politics of resistance and accommodation throughout the Caribbean basin: How did international and local conflicts affect the distribution of United States and Western European investments in the Caribbean basin? What impact did metropolitan investments have on the region's struggles over state power and pattern of economic change? How did the state-building struggles and economic changes of the 1920s influence the region's nationalist break-throughs and defeats during the Great Depression and World War II? What were the consequences of nationalist successes and failures for the subsequent paths of state making and economic development in the Caribbean basin, as well as for North Atlantic investors and governments after World War II?