Angiotensin in the Kidney: A Key to Understanding Hypertension?

A crosstransplantation study between genetically matched angiotensin AT1 receptor knockout and wild-type mice revealed that renal AT1 receptors are required for the development of angiotensin II-induced hypertension (). However, in this experimental setting, hypertension-related left ventricular hypertrophy seemed to depend on blood pressure elevation rather than on the expression of AT1 receptors in the heart.     

Mitochondrial Trafficking in Neurons: A Key Variable in Neurodegeneration?

Mitochondria are the proximate target of a number of different neurotoxins. Typically, impairing of the key bioenergetic function of mitochondria by toxins is considered as the main mechanism of action. However, the effective maintenance of energy generation in neurons depends on the biogenesis, trafficking, and degradation of mitochondria in addition to the traditional bioenergetic functions. We have recently demonstrated that glutamate alters both the trafficking and morphology of mitochondria in primary neurons. In addition, several other potential neurotoxins, including nitric oxide and zinc, inhibit mitochondrial movement and, in some cases, alter morphology too. This suggests that some part of the action of neurotoxins might include the impairment of mitochondrial trafficking in neurons, with the resultant failure of local ATP delivery.     

Models of Electrical Activity: Calibration and Prediction Testing on?the?Same Cell

Mathematical models are increasingly important in biology, and testability is becoming a critical issue. One limitation is that one model simulation tests a parameter set representing one instance of the biological counterpart, whereas biological systems are heterogeneous in their properties and behavior, and a model often is fitted to represent an ideal average. This is also true for models of a cell’s electrical activity; even within a narrowly defined population there can be considerable variation in electrophysiological phenotype. Here, we describe a computational experimental approach for parameterizing a model of the electrical activity of a cell in real time. We combine the inexpensive parallel computational power of a programmable graphics processing unit with the flexibility of the dynamic clamp method. The approach involves 1), recording a cell’s electrical activity, 2), parameterizing a model to the recording, 3), generating predictions, and 4), testing the predictions on the same cell used for the calibration. We demonstrate the experimental feasibility of our approach using a cell line (GH4C1). These cells are electrically active, and they display tonic spiking or bursting. We use our approach to predict parameter changes that can convert one pattern to the other.     

Does the Segregation of Evolution in Biology Textbooks and Introductory Courses Reinforce Students’ Faulty Mental Models of Biology and Evolution?

The well-established finding that substantial confusion and misconceptions about evolution and natural selection persist after college instruction suggests that these courses neither foster accurate mental models of evolution’s mechanisms nor instill an appreciation of evolution’s centrality to an understanding of the living world. Our essay explores the roles that introductory biology courses and textbooks may play in reinforcing undergraduates’ pre-existing, faulty mental models of the place of evolution in the biological sciences. Our content analyses of the three best-selling introductory biology textbooks for majors revealed the conceptual segregation of evolutionary information. The vast majority of the evolutionary terms and concepts in each book were isolated in sections about evolution and diversity, while remarkably few were employed in other sections of the books. Standardizing the data by number of pages per unit did not alter this pattern. Students may fail to grasp that evolution is the unifying theme of biology because introductory courses and textbooks reinforce such isolation. Two goals are central to resolving this problem: the desegregation of evolution as separate “units” or chapters and the active integration of evolutionary concepts at all levels and across all domains of introductory biology.     

Iron: Key player in cancer and cell cycle?

BackgroundIron is an essential element for growth and metabolic activities of all living organisms but remains in its oxyhydroxide ferric ion form in the surrounding. Unavailability of iron in soluble ferrous form led to development of specific pathways and machinery in different organisms to make it available for use and maintain its homeostasis. Iron homeostasis is essential as under different circumstances iron in excess as well as deprivation leads to different pathological conditions in human.ObjectiveThis review highlights the current findings related to iron excess as well as deprivation with regards to cellular proliferation.ConclusionsIron excess is extensively associated with different types of cancers viz. colorectal cancer, breast cancer etc. by producing an oxidative stressed condition and alteration of immune system. Ironically its deprivation also results in anaemic conditions and leads to cell cycle arrest at different phases with mechanism yet to be explored. Iron deprivation arrests cell cycle at G1/S and in some cases at G2/M checkpoints resulting in growth arrest. However, in some cases iron overload arrests cell cycle at G1 phase by blocking certain signalling pathways. Certain natural and synthetic iron chelators are being explored from few decades to combat diseases caused by alteration in iron homeostasis.     

A Social Gradient in Fatal Opioids and Cocaine Related Overdoses?

BackgroundTo determine the existence of a social gradient in fatal overdose cases related to non-prescribed opioids and cocaine use, recorded in Luxembourg between 1994 and 2011.MethodsOverdose cases were individually matched with four controls in a nested case-control study design, according to sex, year of birth, drug administration route and duration of drug use. The study sample, composed of 272 cases and 1,056 controls, was stratified according to a Social Inequality Accumulation Score (SIAS), based on educational attainment, employment, income, financial situation of subjects and the professional status of their father or legal guardian. Least squares linear regression analysis on overdose mortality rates and ridit scores were applied to determine the Relative Index of Inequality (RII) of the study sample.ResultsA negative linear relationship between the overdose mortality rate and the relative socioeconomic position was observed. We found a difference in mortality of 29.22 overdose deaths per 100 drug users in the lowest socioeconomic group compared to the most advantaged group. In terms of the Relative Inequality Index, the overdose mortality rate of opioid and cocaine users with lowest socioeconomic profiles was 9.88 times as high as that of their peers from the highest socioeconomic group (95% CI 6.49–13.26).ConclusionsOur findings suggest the existence of a marked social gradient in opioids and cocaine related overdose fatalities. Harm reduction services should integrate socially supportive offers, not only because of their general aim of social (re)integration but crucially in order to meet their most important objective, that is to reduce drug-related mortality.     

A new primary care rostering and capitation system in Norway: Lessons for Canada?

Providing every patient with a personal primary care physician or, from the physician''s perspective, establishing a stable roster or list of patients is currently being actively debated in Canada. Norway''s system of primary care medicine, similar to Canada''s, faces many of the same problems. In 1992 a trial rostering system with blended funding (capitation, fee-for-service and user fees) was established in 4 Norwegian municipalities. After 3 years of close monitoring, the results of system evaluations have attracted strong interest. This article reports on the benefits and problems encountered with the new rostering system in Norway. If Canada is moving in the same direction, some of the lessons learned may be helpful.     

Using Inquiry and Tree-Thinking to “March Through the Animal Phyla”: Teaching Introductory Comparative Biology in an Evolutionary Context

Biodiversity was originally taught in our Introductory Organismal Biology course at Michigan State University (LB144; freshman/sophomore majors) by rote memorization of isolated facts about organisms. When we moved to an inquiry-based laboratory framework to improve pedagogy, an unfortunate and unforeseen result was the loss of much of our study of biodiversity. In this paper, we describe the restructuring of LB144 to restore the study of biodiversity and organismal groups while retaining the benefits of an inquiry-based approach. The curricular intervention was accomplished through the creation and implementation of a four-week Comparative Biology laboratory stream. During this stream, student research teams recorded and organized observations that they made on a range of organisms and analyzed their data in a phylogenetic framework. During the stream, our students worked through a set of exercises designed to help them learn how to read, interpret, and manipulate phylogenetic trees. We placed particular emphasis on the concept that phylogenetic trees are hypotheses of relationship that can be tested with scientific data. This incorporation of phylogenies and phylogenetic analysis, or “tree-thinking,” into our students’ work provided an explicit synthetic evolutionary framework for their comparative biodiversity studies. End-of-stream products included a team phylogenetic analysis exercise and an individual comparative biology oral presentation.     

Microelements in Stones,Urine, and Hair of Stone Formers: A New Key to the Puzzle of Lithogenesis?

The role of trace elements in lithogenesis is still unclear. The aim of this study was to evaluate the levels of elements in urinary stones and in the urine and hair of stone formers to identify these elements that have synergic correlations in studied materials and may contribute to lithogenesis. A total of 219 consecutive patients with idiopathic upper urinary tract stones were prospectively enrolled in the study. Urine and hair samples were collected from all patients. The content of the stone was evaluated using atomic absorption spectrometry, spectrophotometry, and colorimetric methods. The analysis of 29 elements in stones and hair and 21 elements in urine was performed using inductively coupled plasma-atomic emission spectrometry. The strength of correlation was described with the value of Spearman’s rank correlation coefficient. The positive correlation between concentration of sodium, potassium, magnesium, barium, vanadium, zinc, silicon, phosphorus, and iodine in phosphate stones was observed. Only a few incidental correlations between the composition of stones and the distribution of elements in urine and in hair were found. There were 109 positive two-element correlations between two materials. The most common were observed for vanadium, aluminum, lead, cobalt, and molybdenum. Two-element positive correlations for all samples were established only for three elements: vanadium, lead, and aluminum. Results indicate that analysis of particular elements in hair and urine cannot predict the composition of urinary stones. This study showed, for the first time, correlations between the levels of vanadium, lead, and aluminum in the stones, urine, and hair of stone formers.     

Biology of primate relaxin: A paracrine signal in early pregnancy?

Relaxin is a peptide hormone that exerts numerous effects in a variety of tissues across a broad range of species. Although first identified more than 75 years ago interest in relaxin biology has waxed and waned over the years consistent with peaks and troughs of new experimental data on its wide-ranging biological effects and advances in relaxin enabling technologies. Recent insights into species-dependent differences in relaxin biology during pregnancy have once again stimulated a relative surge of interest in the study of relaxin's reproductive biology. Identification and pharmacological characterization of orphaned relaxin receptors and exploration of its paracrine effects on pregnancy using genomic and proteomic technologies have succeeded in fueling current interest in relaxin research. Primates and non-primate vertebrates exhibit very disparate profiles of relaxin genomics, proteomics and functional biology. Non-human primates appear to exhibit a very close similarity to humans with respect to relaxin reproductive biology but the similarities and subtle differences are only just beginning to be understood. We, and others, have shown that relaxin produces significant changes to the non-human primate endometrium during the peri-implantation period that are consistent with relaxin's long perceived role as a paracrine modulator of pregnancy. The purpose of this review is to summarize the reproductive biology of relaxin in non-human primates with a specific emphasis on the paracrine role of ovarian and endometrial relaxin during embryo implantation and early pregnancy.     

Aesthetics and Power Considerations in Multiple Testing – A Contradiction?

In this paper we discuss aesthetical concepts and requirements for reasonable multiple test procedures. Aesthetical considerations lead to logical decision patterns which are conceivable and, if possible, simple to use and to communicate. Such considerations are sometimes contradictory to the ubiquitous requirement of maximizing power for a multiple test procedure. We illustrate the necessary trade-offs with several examples. We start by considering important logical properties and then discuss three different concepts of monotonicity. Afterwards we have a closer look at the recently proposed \"fallback procedure\" and show that it has some less appealing properties. Finally, we investigate the distribution of the numbers of significant results with respect to both expectation and variance.     

Repeat HIV Testing at Voluntary Testing and Counseling Centers in Croatia: Successful HIV Prevention or Failure to Modify Risk Behaviors?

HIV testing plays a critical role in preventing the spread of the virus and identifying infected individuals in need of care. Voluntary counseling and testing centers (VCTs) not only conduct testing but they also provide counseling. Since a proportion of people who test negative for HIV on their previous visit will return for retesting, the frequency of retesting and the characteristics of those who retest may provide insights into the efficacy of testing and counseling strategies. In this cross-sectional, retrospective study of 1,482 VCT clients in Croatia in 2010, 44.3% had been tested for HIV before. The rate of repeat HIV testing is lower in Croatia than in other countries. Men who have sex with men (MSM) clients, those with three or more sexual partners in the last 12 months, consistent condom users with steady partners, and intravenous drug users were more likely to be repeat testers. This finding suggests that clients presenting for repeat HIV testing are those who self-identify as being at a higher risk of infection. Our data showed that testing positive for HIV was not associated with repeat testing. However, the effects of repeat testing on HIV epidemiology needs to be explored.     

Finite Element Modelling and Simulations in Dentistry: A Bibliography 1990–2003

The paper gives a bibliographical review of the finite element modelling and simulations in dentistry from the theoretical as well as practical points of view. The bibliography lists references to papers, conference proceedings and theses/dissertations that were published between 1990 and 2003. At the end of this paper, more than 700 references are given dealing with subjects such as: dental materials; oral and maxillofacial mechanics and surgery; orthodontics, tooth movement, orthodontic appliances; root canals, filling and therapy; dental restorations and other topics.     

Are Individual Differences in Reading Speed Related to Extrafoveal Visual Acuity and Crowding?

Readers differ considerably in their speed of self-paced reading. One factor known to influence fixation durations in reading is the preprocessing of words in parafoveal vision. Here we investigated whether individual differences in reading speed or the amount of information extracted from upcoming words (the preview benefit) can be explained by basic differences in extrafoveal vision—i.e., the ability to recognize peripheral letters with or without the presence of flanking letters. Forty participants were given an adaptive test to determine their eccentricity thresholds for the identification of letters presented either in isolation (extrafoveal acuity) or flanked by other letters (crowded letter recognition). In a separate eye-tracking experiment, the same participants read lists of words from left to right, while the preview of the upcoming words was manipulated with the gaze-contingent moving window technique. Relationships between dependent measures were analyzed on the observational level and with linear mixed models. We obtained highly reliable estimates both for extrafoveal letter identification (acuity and crowding) and measures of reading speed (overall reading speed, size of preview benefit). Reading speed was higher in participants with larger uncrowded windows. However, the strength of this relationship was moderate and it was only observed if other sources of variance in reading speed (e.g., the occurrence of regressive saccades) were eliminated. Moreover, the size of the preview benefit—an important factor in normal reading—was larger in participants with better extrafoveal acuity. Together, these results indicate a significant albeit moderate contribution of extrafoveal vision to individual differences in reading speed.     

Invasion Success and Community Resistance in Single and Multiple Species Invasion Models: Do the Models Support the Conclusions?

Elton's concept of community-level resistance to invasion has derived significant theoretical support from community assembly models in which species invade (colonize) singly at low densities. Several theoretical models have provided support to this concept and are frequently cited as providing evidence that invasion resistance occurs in nature. The underlying assumptions of these models however, are derived from island or island-like systems in which species invade infrequently at low abundances. We suggest that these island-like models cannot be generalized to systems in which species arrive in greater frequencies and densities. To investigate the effects of altering the basic assumptions of these original models, we utilized assembly algorithms similar to those used in previous studies, but allowed either two species to invade per time step or single species invasions at relatively high inoculation densities. In these models, invasion resistance only occurred when the invasion process was restricted to single species invading at low densities (as in previous models). When two species were allowed to invade per time step, invasion resistant states did not occur in any of 20 simulated communities, even after 10,000 invasion events. Relaxation of the assumption of invasion at low density also resulted in a lack of invasion resistance. These results may explain why the strict concept of complete invasion resistance appears only to operate in island and island-like systems.     

Cell wall integrity maintenance in plants: Lessons to be learned from yeast?

The plant cell wall is involved in different biological processes like cell morphogenesis and response to biotic/abiotic stress. Functional integrity of the wall is apparently being maintained during these processes by changing structure/composition and coordinating cell wall with cellular metabolism. In S.cerevisiae a well-characterized mechanism exists that is maintaining functional integrity of yeast the cell wall during similar processes. During the last years it has become obvious that plants have evolved a mechanism to monitor and maintain functional integrity of their cell walls. However, our understanding of the mechanism is rather limited. The available evidence suggests that similar signaling cascades may be involved and particular protein activities may be conserved between plants and yeast. Here we review the available evidence briefly and highlight similarities between yeast and plants that could help us to understand the mode of action of the signaling cascades maintaining plant cell wall integrity.     

Explanatory Models and Mental Health Treatment: Is Vodou an Obstacle to Psychiatric Treatment in Rural Haiti?

Vodou as an explanatory framework for illness has been considered an impediment to biomedical psychiatric treatment in rural Haiti by some scholars and Haitian professionals. According to this perspective, attribution of mental illness to supernatural possession drives individuals to seek care from houngan-s (Vodou priests) and other folk practitioners, rather than physicians, psychologists, or psychiatrists. This study investigates whether explanatory models of mental illness invoking supernatural causation result in care-seeking from folk practitioners and resistance to biomedical treatment. The study comprised 31 semi-structured interviews with community leaders, traditional healers, religious leaders, and biomedical providers, 10 focus group discussions with community members, community health workers, health promoters, community leaders, and church members; and four in-depth case studies of individuals exhibiting mental illness symptoms conducted in Haiti's Central Plateau. Respondents invoked multiple explanatory models for mental illness and expressed willingness to receive treatment from both traditional and biomedical practitioners. Folk practitioners expressed a desire to collaborate with biomedical providers and often referred patients to hospitals. At the same time, respondents perceived the biomedical system as largely ineffective for treating mental health problems. Explanatory models rooted in Vodou ethnopsychology were not primary barriers to pursuing psychiatric treatment. Rather, structural factors including scarcity of treatment resources and lack of psychiatric training among health practitioners created the greatest impediments to biomedical care for mental health concerns in rural Haiti.     

Interprofessional Education for Whom? — Challenges and Lessons Learned from Its Implementation in Developed Countries and Their Application to Developing Countries: A Systematic Review

Background

Evidence is available on the potential efficacy of interprofessional education (IPE) to foster interprofessional cooperation, improve professional satisfaction, and improve patient care. While the intention of the World Health Organization (WHO) is to implement IPE in all countries, evidence comes from developed countries about its efficiency, challenges, and barriers to planning and implementing IPE. We therefore conducted this review to examine challenges of implementing IPE to suggest possible pathways to overcome the anticipated challenges in developing countries.

Methods

We searched for literatures on IPE in PubMed/MEDLINE, CINAHL, PsycINFO, and ERIC databases. We examined challenges or barriers and initiatives to overcome them so as to suggest methods to solve the anticipated challenges in developing countries. We could not conduct a meta-analysis because of the qualitative nature of the research question and the data; instead we conducted a meta-narrative of evidence.

Results

A total of 40 out of 2,146 articles were eligible for analyses in the current review. Only two articles were available from developing countries. Despite the known benefits of IPE, a total of ten challenges or barriers were common based on the retrieved evidence. They included curriculum, leadership, resources, stereotypes and attitudes, variety of students, IPE concept, teaching, enthusiasm, professional jargons, and accreditation. Out of ten, three had already been reported in developing countries: IPE curriculum, resource limitations, and stereotypes.

Conclusion

This study found ten important challenges on implementing IPE. They are curriculum, leadership, resources, stereotypes, students'' diversity, IPE concept, teaching, enthusiasm, professional jargons, and accreditation. Although only three of them are already experienced in developing countries, the remaining seven are potentially important for developing countries, too. By knowing these challenges and barriers in advance, those who implement IPE programs in developing countries will be much more prepared, and can enhance the program''s potential success.