Studies with the mutation,diabetes, in the mouse

Summary The mutation, diabetes (db), that occurred in the C57BL/Ks strain of mice is a unit autosomal recessive gene with full penetrance, and causes metabolic disturbances in homozygous mice resembling diabetes mellitus in man. Abnormal deposition of fat at 3 to 4 weeks of age is followed by hyperglycemia, polyuria and glycosuria. The diabetic condition appears to develop in two stages. In the early stage, there are marked increases in the levels of plasma insulin, the rates of lipogenesis, gluconeogenesis, and glucose oxidation, and there is a reduction of-cell granules in the islet of Langerhans with other changes suggestive of a compensating adaptation to increased insulin demand. On the other hand, the late stage is characterized by a near normal level of circulating insulin, a marked decrease in glucose utilization but with a continued high rate of gluconeogenesis. These findings suggest a defect in the peripheral utilization of insulin rather than in the synthesis and release of the hormone from the pancreas.Supported in part by United States Public Health services grant # AM 06871 from the National Institute of Arthritis and Metabolic Diseases and grant # HD 00468 from the National Institute of Human Development.     

Gender, age, society, culture, and the patient's perspective in the functional gastrointestinal disorders

Patients with functional gastrointestinal disorders (FGID) often experience emotional distress, a perceived lack of validation, and an unsatisfactory experience with health care providers. A health care provider can provide the patient with a framework in which to understand and legitimize their symptoms, remove self-doubt or blame, and identify factors that contribute to symptoms that the patient can influence or control. This framework can be strengthened with the consideration of various important factors that impact FGID but are often overlooked. These include gender, age, society, culture, and the patient's perspective. There is evidence for sex- and gender-related differences in FGID, particularly irritable bowel syndrome (IBS). Whereas the majority of FGID, including IBS, bloating, constipation, chronic functional abdominal pain, and pelvic floor dysfunction, are more prevalent in women than men, functional esophageal and gastroduodenal disorders do not appear to vary by gender. Limited studies suggest that sex differences in visceral perception, cardioautonomic responses, gastrointestinal motility, and brain activation patterns to visceral stimuli exist in IBS. Gender differences in social factors, psychological symptoms, and response to psychological treatments have not been adequately studied. However, there appears to be a greater clinical response to serotonergic agents developed for IBS in women compared to men. The impact of social and cultural factors on the meaning, expression, and course of FGID are important. The prevalence of IBS appears to be lower in non-Western than Western countries. Although further studies are needed, the existing literature suggests that they are important to consider from both research and clinical perspectives.     

Insights on linking forests, trees, and people from the air, on the ground, and in the laboratory

Governing natural resources sustainably is a continuing struggle. Major debates occur over what types of policy "interventions" best protect forests, with choices of property and land tenure systems being central issues. Herein, we provide an overview of findings from a long-term interdisciplinary, multiscale, international research program that analyzes the institutional factors affecting forests managed under a variety of tenure arrangements. This program analyzes satellite images, conducts social-ecological measurements on the ground, and tests the impact of structural variables on human decisions in experimental laboratories. Satellite images track the landscape dimensions of forest-cover change within different management regimes over time. On-the-ground social-ecological studies examine relationships between forest conditions and types of institutions. Behavioral studies under controlled laboratory conditions enhance our understanding of explicit changes in structure that affect relevant human decisions. Evidence from all three research methods challenges the presumption that a single governance arrangement will control overharvesting in all settings. When users are genuinely engaged in decisions regarding rules affecting their use, the likelihood of them following the rules and monitoring others is much greater than when an authority simply imposes rules. Our results support a frontier of research on the most effective institutional and tenure arrangements for protecting forests. They move the debate beyond the boundaries of protected areas into larger landscapes where government, community, and comanaged protected areas are embedded and help us understand when and why deforestation and regrowth occur in specific regions within these larger landscapes.     

Programmed necrosis, not apoptosis, in the heart

It is well known that apoptosis is an actively mediated cell suicide process. In contrast, necrosis, a morphologically distinct form of cell death, has traditionally been regarded as passive and unregulated. Over the past decade, however, experiments in Caenorhabditis elegans and mammalian cells have revealed that a significant proportion of necrotic death is, in fact, actively mediated by the doomed cell. Although a comprehensive understanding of necrosis is still lacking, some key molecular events have come into focus. Cardiac myocyte apoptosis and necrosis are prominent features of the major cardiac syndromes. Accordingly, the recognition of necrosis as a regulated process mandates a reexamination of cell death in the heart. This review discusses pathways that mediate programmed necrosis, how they intersect with apoptotic pathways, roles of necrosis in heart disease, and new therapeutic opportunities that the regulated nature of necrosis presents.     

Adipokines,inflammation, and the endothelium in diabetes

Cytokines are biologically active low molecular weight proteins that possess several endocrine and metabolic functions and are known products of the immune system and inflammation. Several of these cytokines were shown to be independent risk factors for cerebrovascular and coronary artery disease. Because visceral and subcutaneous adipose tissues are the major sources of cytokines (adipokines), increased adipose tissue mass is associated with alteration in adipokine production (eg, overexpression of tumor necrosis factor-α [TNF-α], interleukin-6 [IL-6], plasminogen activator inhibitor-1 [PAI-1], and underexpression of adiponectin in adipose tissue). The proinflammatory status associated with these changes provides a potential link between insulin resistance and endothelial dysfunction, the early stage in the atherosclerotic process, in obese individuals, and in type 2 diabetic patients. Reduction of adipose tissue mass through weight reduction in association with exercise reduces TNF-α, IL-6, and PAI-1, increases adiponectin, and is associated with improved insulin sensitivity and endothelial function.     

Irrigation, schistosomiasis, and malaria in the Logone Valley, Cameroon

Field studies of a rice irrigation project in Mayo-Danai, North Cameroon permitted a direct comparison between pre- and post-development data relating to schistosomiasis and malaria infection. A stratified sample of 4,000 inhabitants, representing 8% of the population living in 28 areas at the time of the first survey, was investigated 5 times between 1979 and 1985. Due to the significant population increase since 1982, 1,500 persons were added to the initial sample. The prevalence of schistosomiasis and malaria remained constant over the 6 years. No changes in the transmission sites were observed. Malacological investigations showed a decrease in the snail population in the project area. Sanitation activities (i.e., drain cleaning and well construction) and decreased rainfall contributed to this situation. The prevalence of infection among the migrants was low. High prevalence of schistosomiasis was found only in villages located along a previously contaminated temporary river.     

Neurohypophysial hormones and cardiac activity in the frog, Rana tigrina, and in the snake, Ptyas mucosa

The cardiac effects of neurohypophysial hormones (NH) in the frog, Rana tigrina, and in the snake, Ptyas mucosa, were studied in isolated atrial preparations. Arginine vasopressin (AVP), vasotocin (AVT), isotocin (ISN), mesotocin (MSN), and oxytocin (OXY) produced dose-related positive chronotropic and inotropic responses in the frog atria. AVT was the most potent. In the snake, AVP, AVT, MSN, and OXY produced dose-related positive inotropic but not chronotropic changes. OXY was the most potent. Data indicate that there is a direct action of NH on the heart in both animals, the atrial rate and tension responses to NH are not coupled, and judging by the efficacy, AVT and OXY might be the natural NH in the frog and snake, respectively, which may account for the high concentrations required of other NH to be cardiac stimulating.     

Institutional radicalization, the state, and the development process in Africa

The concept of "institutional radicalization" or "the changing of institutions from their roots" is put forward as critical for understanding the manner in which civil societies in most African countries have been grappling with the challenges of development. Given the well embedded precapitalist social formation in most African countries, various institutions have been radicalized around such critical identities as age, gender, land, occupation, credit, community, and rituals of solidarity to promote development. However, until the state intervenes to legitimize these initiatives of civil societies, their full impact on the development process is bound to be moot. The enormous tasks entailed in such legitimization through identifying, registering, realigning, providing incentives, directing, and monitoring these radicalized institutions remain critical and imperative for African countries if they are to accelerate and deepen the extent of their integration into the global free market economy and democratic governance.     

Essential elements (Fe, Cu, Mn, Zn, Se, As) in the liver and lungs with alimentary obesity in the experiment

The purpose - to establish the role of lungs in the metabolic processes in normal and alimentary obesity. The method of X-ray fluorescence analysis using synchrotron radiation, the determination of concentrations Fe, Cu, Mn, Zn, Se, As in the tissue of the lungs and liver in 19 control rats and 19 rats with alimentary obesity. On the basis of many strengths and very strong positive correlation between the content of chemical elements shows that in the control rats, fasting metabolism in the lung more intense than the liver, which in case of obesity is significantly reduced. After receiving the lard in the lungs decreases the number of correlations between the concentrations of microelements in the control animals. Obesity changing their character, indicating a switch of metabolism in connection with the utilization of triglycerides in the body of the control rats, and a malfunction of this process in obesity.