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1.
Since there has been no significant increase in cancer cure rates in recent years that can be attributed to the treatment method alone, new and more radical procedures have been introduced in an effort to improve the results. In radiation therapy this has taken the form of supervoltage generators and in the use of high energy sources of radiation such as Cobalt 60 and Cesium 137. As this trend gains momentum, the place and future of orthovoltage therapeutic radiation (250 to 400 kilovolts) must be considered. General agreement is that supervoltage radiation offers an increase in depth dose and fewer local and systemic reactions, but it is too early to assess any change in cure rate. Measured against this is the danger of deep tissue damage, less relative biological efficiency and increased costs.In view of our ignorance regarding cancer, abandoning proved procedures prematurely is unjustified. The most promising trend lies in improved training and in the skillful use of what we have. While it may be that radiation of higher voltages will improve the morbidity and mortality rates, it would be better to concentrate these new modalities in centers where large numbers of cases are available.  相似文献   

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Neuronal Death: Is There a Role for Astrocytes?   总被引:8,自引:0,他引:8  
Astrocytes are ubiquitous in the brain and have multiple functions. It is becoming increasingly clear that they play an important role in monitoring the neuromicroenvironment in CNS and in information processing or signaling in the nervous system in normal conditions and respond to CNS injuries in a gradual and varied way. It is still debated whether such reactions are beneficial or detrimental. It was believed that reactive astrogliosis observed in most neurological disorders may regulate the removal of toxic compounds produced by damaged neurons and support neuronal growth by releasing trophic factors. However it was also suggested that astrocytes contribute to a decline of neurologic function, for example by accumulation and release of excitotoxic aminoacids after ischemia and oxidative stress, formation of epileptogenic scars in response to CNS injury and metabolism of protoxins to potent toxins. In a number of metabolic diseases astrocytes, not neurons, may be the primary target. The astrocyte's role in normal and pathological conditions will be discussed in the light of recent information about their metabolism, receptor distribution and release.  相似文献   

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Objective

Differences between women and men in political and economic empowerment, education, and health risks are well-documented. Similar gender inequities in access to care and medicines have been hypothesized but evidence is lacking.

Methods

We analyzed 2002 World Health Survey data for 257,922 adult respondents and 80,932 children less than 5 years old from 53 mostly low and middle-income countries. We constructed indicators of need for, access to, and perceptions of care, and we described the number of countries with equal and statistically different proportions of women and men for each indicator. Using multivariate logistic regression models, we estimated effects of gender on our study outcomes, overall and by household poverty.

Findings

Women reported significantly more need for care for three of six chronic conditions surveyed, and they were more likely to have at least one of the conditions (OR 1.41 [95% CI 1.38, 1.44]). Among those with reported need for care, there were no consistent differences in access to care between women and men overall (e.g., treatment for all reported chronic conditions, OR 1.00 [0.96, 1.04]) or by household poverty. Of concern, access to care for chronic conditions was distressingly low among both men and women in many countries, as was access to preventive services among boys and girls less than 5 years old.

Conclusions

These cross-country results do not suggest a systematic disadvantage of women in access to curative care and medicines for treating selected chronic conditions or acute symptoms, or to preventive services among boys and girls.  相似文献   

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Objective: To determine relative trends in prevalence for overweight for adults compared with children across high‐income countries (Australia, United Kingdom, and United States), middle‐income countries (Brazil and Russia), and low‐income countries (China and Indonesia). Research Methods and Procedures: Extant nationally representative survey data from 1971 to the present are used. Prevalence of overweight for adults ≥18.0 years of age and children 6.0 to 17.9 years of age were used. Absolute and relative annual rates of change in prevalence of overweight in children and adults were the key outcomes. Results: Absolute rates of increase in overweight were higher among adults than among children in all studied countries except Australia. However, relative rates of increase in overweight indicate faster increases in overweight among children in Brazil, China, and the three high‐income countries. As a result, the relative excess of overweight among adults, seen initially in all countries, increased in Indonesia and Russia, but it decreased in Australia, Brazil, China, United Kingdom, and United States. In Brazil, time trends indicate an acceleration in the annual rate of change in overweight for children and a deceleration for adults, whereas in the United States, the increase in overweight shows acceleration for both children and adults. Discussion: In absolute terms, overweight increased faster among children than adults only in Australia; however, the relative gap between children and adults is closing in four additional countries, Brazil, China, the United Kingdom, and the United States.  相似文献   

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Background

Health behaviors, as important modifiable determinants of health, are consistently targeted by prevention messages. Teachers, as educators and role models, may play a key-role in bringing such messages to children and adolescents. It is not clear which areas of prevention could be improved in collaboration with teachers to promote healthy behaviors at the population level through health education in schools.

Methods

to evaluate teacher’s health awareness, we compared their health/risk behaviors to those of non-teachers, taking into account demographic and socioeconomic factors that could confound crude differences. We used data from the 2010 Health Barometer, a cross-sectional nationally-representative French survey conducted by telephone among 27,653 persons aged 15–85. Adjusting sequentially for potential confounders, we compared six indicators of lifestyle and risky conducts (at-risk drinking, current smoking, cannabis use, gambling, corpulence, sleep duration) between teachers (n = 725) and two comparison groups: other occupations (n = 12,483) on the one hand, and other intermediate and managerial/professional occupations (n = 6,026) on the other.

Results

In the fully-adjusted models, teachers were less likely than other occupations to smoke, to have used cannabis in the last 12 months, to gamble regularly and to be overweight or obese. When restricting the comparison group to other occupations belonging to the same socio-professional category, differences were attenuated, but remain highly significant for tobacco, cannabis and gambling. No significant differences were observed between teachers and non-teachers regarding alcohol use and sleep duration, once important confounders had been adjusted for.

Conclusions

Our results suggest that teachers behave on the whole more healthily than other adults with a similar demographic and socioeconomic profile. The absence of a teacher distinction toward at-risk drinking needs to be examined in more detail.  相似文献   

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ObjectiveTo determine whether a school-based health promotion program affects children’s weekend physical activity and whether this effect varies according to socioeconomic-status.MethodsThis was a quasi-experimental trial of school-based programs on physical activity levels implemented in disadvantaged neighborhoods in Alberta, Canada. In 2009 and 2011, 7 full days of pedometer data were collected from cross-sectional samples of grade 5 students (age 10–11 years) from 10 intervention schools in low-socioeconomic neighbourhoods and 20 comparison schools in middle-socioeconomic neighbourhoods. Multilevel models assessed differences in step-counts between intervention and comparison groups over-time by weight (objectively measured) and socioeconomic status subgroups.ResultsIn 2009, children from intervention schools were less active on weekends relative to comparison schools (9212 vs. 11186 steps/day p<0.01). Two years later, daily step-counts on weekend days among children in low socioeconomic intervention schools increased such that they approximated those of children from middle socioeconomic comparison schools (12148 vs. 12121 steps/day p = 0.96). The relative difference in steps between intervention and comparison schools on weekends reduced from -21.4% to 0.2% following the intervention. The normalization of weekend step counts was similar for normal weight (–21.4% to +2.0%) and overweight (-19.1 to +3.9%) children, and was balanced across socioeconomic subgroups.ConclusionsThese data suggest that school-based health promotion is effective for reducing inequities in physical activity levels outside school hours. Investments in school-based health promotion lead to behavior modification beyond the school environment.

Trial Registration

ClinicalTrials.gov NCT01914185  相似文献   

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Is There a Role for the Apex in Shoot Geotropism?   总被引:3,自引:1,他引:2       下载免费PDF全文
Experiments with horizontal etiolated sunflower (Helianthus annuus L.) seedlings supported centrally such that both apical and basal ends are free to react to geostimulus, revealed that the apical end commences curvature 1 to 2 hours earlier than the basal end. The later curvature in the basal region is a consequence of the absence of growth in the initial period rather than merely slower growth. A comparison of zonal growth rates in a vertical and a horizontal seedling confirmed that geostimulus induces a renewal of growth in a region where growth had ceased. Removing the apical half of the hypocotyl showed that the curvature resulting from this growth initiation in the basal region is dependent on attachment to the apical region. Evidence that this dependence is unlikely to be due to energy deficiency is adduced. The prior response of the apical end to geostimulus and the apically dependent later initiation of new growth in the basal region are compatible with the delay inherent in message transport from apex to base and are considered as evidence for apical involvement in the totality of the seedling's georesponse.  相似文献   

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Posing the question of whether the precautionary principle has a role in risk assessment effectively constrains any debate of the issue within a framework predicated on the assumption that application of risk assessment is inevitable in the formulation of regulatory decisions. The question can equally validly be expressed in terms of whether there is a role for risk assessment in the formulation of precautionary legislation. This allows the debate then to turn on consideration of two questions: Firstly, does the precautionary principle have a role in policy development? and secondly, is this role consistent and compatible with a risk based approach to regulation? When recast in these terms, a more holistic comparison of the aims and objectives of both approaches and of their relative power in the formulation of regulation becomes possible. This leads to the conclusion that the precautionary principle is, when defined and applied correctly, scientifically more robust than risk assessment. Precautionary approaches utilize scientific information and conform robustly to a scientific process but also explicitly incorporate indeterminacies into the decision making framework. Moreover, the precautionary principle when applied to environmental regulation, is more likely to lead to regulation consistent with global sustainability. On this premise, this paper argues that risk based approaches are essentially incompatible with approaches based on the precautionary paradigm, and that of the two, risk assessment is more likely to lead to unsustainable underprotection of the environment.  相似文献   

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Background

The use of insecticidal bed nets is found to be an effective public health tool for control of malaria, especially for under-five children and pregnant women. BRAC, an indigenous Bangladeshi non-governmental development organization, started working in the East African state of Uganda in June 2006. As part of its efforts to improve the health and well-being of its participants, BRAC Uganda has been distributing long lasting insecticide-treated bed nets (LLIN) at a subsidized price through health volunteers since February 2008. This study was conducted in March-April 2009 to examine how equitable the programme had been in consistence with BRAC Uganda''s pro-poor policy.

Methodology/Principal Findings

Information on possession of LLINs and relevant knowledge on its proper use and maintenance was collected from households either with an under-five child and/or a pregnant woman. The sample included three villages from each of the 10 branch offices where BRAC Uganda''s community-based health programme was operating. Data were collected by trained enumerators through face-to-face interviews using a hand-held personal digital assistant (PDA). Findings reveal that the study population had superficial knowledge on malaria and its transmission, including the use and maintenance of LLINs. The households'' rate of possession of bed nets (41–59%), and the proportion of under-five children (17–19%) and pregnant women (25–27%) who reported sleeping under an LLIN were not encouraging. Inequity was observed in the number of LLINs possessed by the households, in the knowledge on its use and maintenance, and between the two programme areas.

Conclusions/Significance

The BRAC Uganda''s LLINs distribution at a subsidized price appeared to be inadequate and inequitable, and BRAC''s knowledge dissemination is insufficient for initiating preventive actions such as proper use of LLINs to interrupt malaria transmission. Findings contribute to the on-going debate on LLINs distribution in Africa and make a strong case for its free distribution.  相似文献   

15.
Scedosporium species are increasingly encountered as fungal pathogens. Species identification is important due to species-specific differences in epidemiology, antifungal susceptibility and virulence. Histology and culture-based identification are hampered by their low sensitivity and specificity. The use of new selective media has improved the recovery rate from clinical samples. Molecular methods, including multiplex PCR, PCR-RFLP analysis, DNA sequencing, oligonucleotide arrays, real-time PCR, rolling circle amplification, are increasingly used for species identification. Most recently, Matrix-Assisted Laser Desorption-Time of Flight Mass Spectrometry has been successfully applied as a tool for rapid identification of clinically relevant Scedosporium species. This review aims to summarize the methods currently used to guide the clinical microbiology laboratory in the selection of the most appropriate identification techniques. This will aid the laboratory in making a fast and reliable diagnosis that enables the clinician to make correct treatment choices.  相似文献   

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Achieving and maintaining effective suppression of serum testosterone levels in men treated with androgen ablation is one of the essential strategies in the management of prostate cancer. Historically, a serum testosterone below 50 ng/dL was considered to be the castrate level. Current data suggest that the new target for either surgical or chemical castration is a serum testosterone level of lower than 20 ng/dL in an attempt to maximize therapeutic outcomes. Testosterone breakthrough and the acute-on-chronic effects of administration of a luteinizing hormone-releasing hormone analogue may cause testosterone levels to periodically rise, sometimes to noncastrate levels. The goal of androgen ablation is to identify those agents that will most consistently achieve and maintain the lowest testosterone levels possible.Key words: Prostate cancer, Androgen ablation, LHRH analogues, LHRH antagonists, TestosteroneThe cornerstone of understanding the basic biology of prostate cancer relies upon the important discovery that prostate cancer is a hormonally responsive tumor. The current use of androgen ablation therapy in prostate cancer includes treatment based on serum prostate-specific antigen (PSA) only or local recurrence; neoadjuvant or adjuvant treatment of high-risk disease, usually in combination with radiation therapy; and treatment of patients with metastatic disease regardless of symptoms. The American Society of Clinical Oncology (ASCO) 2007 guidelines and National Comprehensive Cancer Network (NCCN) 2009 guidelines recommend either luteinizing hormone-releasing hormone (LHRH) agonists or bilateral orchiectomy as first-line therapy for men with advanced prostate cancer.1,2Medical or chemical castration is almost exclusively performed by the use of injectable LHRH analogues, with a minor role for estrogen and limited experience with LHRH antagonists. Surgical castration through bilateral orchiectomy is infrequently used today.Intermittent hormonal therapy (IHT) is being investigated as an alternative to continuous hormonal therapy with a potential for reduced morbidity and a delay of the progression to hormone-refractory disease.3 Although intermittent therapy may rely upon restoring a normal testosterone level, it is believed that the testosterone level should be as low as possible when the patient is on treatment, thus generating the lowest serum PSA level possible and likely improving outcome.4 Although the data on IHT are promising, trials reported thus far are relatively small and somewhat underpowered, and it is likely that its use will increase in the future as trials mature.There is growing recognition that many men may not achieve acceptable levels of testosterone using androgen ablation. This has led to a renewed interest in the significance of the testosterone level in the modern era of prostate cancer management. Can we define the best castration therapy for prostate cancer? Is this the therapy that provides the lowest and most consistent levels of testosterone suppression? To quote Dr. Claude Schulman in a recent editorial: “less is more.”5  相似文献   

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《PloS one》2012,7(11)
The geographic distribution of Bornean orang-utans and its overlap with existing land-use categories (protected areas, logging and plantation concessions) is a necessary foundation to prioritize conservation planning. Based on an extensive orang-utan survey dataset and a number of environmental variables, we modelled an orang-utan distribution map. The modelled orang-utan distribution map covers 155,106 km2 (21% of Borneo''s landmass) and reveals four distinct distribution areas. The most important environmental predictors are annual rainfall and land cover. The overlap of the orang-utan distribution with land-use categories reveals that only 22% of the distribution lies in protected areas, but that 29% lies in natural forest concessions. A further 19% and 6% occurs in largely undeveloped oil palm and tree plantation concessions, respectively. The remaining 24% of the orang-utan distribution range occurs outside of protected areas and outside of concessions. An estimated 49% of the orang-utan distribution will be lost if all forest outside of protected areas and logging concessions is lost. To avoid this potential decline plantation development in orang-utan habitats must be halted because it infringes on national laws of species protection. Further growth of the plantation sector should be achieved through increasing yields in existing plantations and expansion of new plantations into areas that have already been deforested. To reach this goal a large scale island-wide land-use masterplan is needed that clarifies which possible land uses and managements are allowed in the landscape and provides new standardized strategic conservation policies. Such a process should make much better use of non-market values of ecosystem services of forests such as water provision, flood control, carbon sequestration, and sources of livelihood for rural communities. Presently land use planning is more driven by vested interests and direct and immediate economic gains, rather than by approaches that take into consideration social equity and environmental sustainability.  相似文献   

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Background

Research ethics consultation programs are being established with a goal of addressing the ethical, societal, and policy considerations associated with biomedical research. A number of these programs are modelled after clinical ethics consultation services that began to be institutionalized in the 1980s. Our objective was to determine biomedical science researchers'' perceived need for and utility of research ethics consultation, through examination of their perceptions of whether they and their institutions faced ethical, social or policy issues (outside those mandated by regulation) and examination of willingness to seek advice in addressing these issues. We conducted telephone interviews and focus groups in 2006 with researchers from Stanford University and a mailed survey in December 2006 to 7 research universities in the U.S.

Findings

A total of 16 researchers were interviewed (75% response rate), 29 participated in focus groups, and 856 responded to the survey (50% response rate). Approximately half of researchers surveyed (51%) reported that they would find a research ethics consultation service at their institution moderately, very or extremely useful, while over a third (36%) reported that such a service would be useful to them personally. Respondents conducting human subjects research were more likely to find such a service very to extremely useful to them personally than respondents not conducting human subjects research (20% vs 10%; chi2 p<0.001).

Conclusion

Our findings indicate that biomedical researchers do encounter and anticipate encountering ethical and societal questions and concerns and a substantial proportion, especially clinical researchers, would likely use a consultation service if they were aware of it. These findings provide data to inform the development of such consultation programs in general.  相似文献   

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