1,546 research outputs found
Identification of sex hormone-binding globulin in the human hypothalamus
Gonadal steroids are known to influence hypothalamic functions through both genomic and non-genomic pathways. Sex hormone-binding globulin ( SHBG) may act by a non-genomic mechanism independent of classical steroid receptors. Here we describe the immunocytochemical mapping of SHBG-containing neurons and nerve fibers in the human hypothalamus and infundibulum. Mass spectrometry and Western blot analysis were also used to characterize the biochemical characteristics of SHBG in the hypothalamus and cerebrospinal fluid (CSF) of humans. SHBG-immunoreactive neurons were observed in the supraoptic nucleus, the suprachiasmatic nucleus, the bed nucleus of the stria terminalis, paraventricular nucleus, arcuate nucleus, the perifornical region and the medial preoptic area in human brains. There were SHBG-immunoreactive axons in the median eminence and the infundibulum. A partial colocalization with oxytocin could be observed in the posterior pituitary lobe in consecutive semithin sections. We also found strong immunoreactivity for SHBG in epithelial cells of the choroid plexus and in a portion of the ependymal cells lining the third ventricle. Mass spectrometry showed that affinity-purified SHBG from the hypothalamus and choroid plexus is structurally similar to the SHBG identified in the CSF. The multiple localizations of SHBG suggest neurohypophyseal and neuroendocrine functions. The biochemical data suggest that CSF SHBG is of brain rather than blood origin. Copyright (c) 2005 S. Karger AG, Base
<i>Trypanosoma brucei rhodesiense</i> transmitted by a single tsetse fly bite in vervet monkeys as a model of human African trypanosomiasis
Sleeping sickness is caused by a species of trypanosome blood parasite that is transmitted by tsetse flies. To understand better how infection with this parasite leads to disease, we provide here the most detailed description yet of the course of infection and disease onset in vervet monkeys. One infected tsetse fly was allowed to feed on each host individual, and in all cases infections were successful. The characteristics of infection and disease were similar in all hosts, but the rate of progression varied considerably. Parasites were first detected in the blood 4-10 days after infection, showing that migration of parasites from the site of fly bite was very rapid. Anaemia was a key feature of disease, with a reduction in the numbers and average size of red blood cells and associated decline in numbers of platelets and white blood cells. One to six weeks after infection, parasites were observed in the cerebrospinal fluid (CSF), indicating that they had moved from the blood into the brain; this was associated with a white cell infiltration. This study shows that fly-transmitted infection in vervets accurately mimics human disease and provides a robust model to understand better how sleeping sickness develops
Renewing Criminalized and Hegemonic Cultural Landscapes
The Mafia's long historical pedigree in Mezzogiorno, Southern Italy, has empowered the Mafioso as a notorious, uncontested, and hegemonic figure. The counter-cultural resistance against the mafiosi culture began to be institutionalized in the early 1990s. Today, Libera Terra is the largest civil society organization in the country that uses the lands confiscated from the Mafia as a space of cultural repertoire to realize its ideals. Deploying labor force through volunteer participation, producing biological fruits and vegetables, and providing information to the students on the fields are the principal cultural practices of this struggle. The confiscated lands make the Italian experience of anti-Mafia resistance a unique example by connecting the land with the ideals of cultural change. The sociocultural resistance of Libera Terra conveys a political message through these practices and utters that the Mafia is not invincible. This study draws the complex panorama of the Mafia and anti-Mafia movement that uses the ‘confiscated lands’ as cultural and public spaces for resistance and socio-cultural change. In doing so, this article sheds new light on the relationship between rural criminology and crime prevention policies in Southern Italy by demonstrating how community development practice of Libera Terra changes the meaning of landscape through iconographic symbolism and ethnographic performance
Photoswitchable diacylglycerols enable optical control of protein kinase C.
Increased levels of the second messenger lipid diacylglycerol (DAG) induce downstream signaling events including the translocation of C1-domain-containing proteins toward the plasma membrane. Here, we introduce three light-sensitive DAGs, termed PhoDAGs, which feature a photoswitchable acyl chain. The PhoDAGs are inactive in the dark and promote the translocation of proteins that feature C1 domains toward the plasma membrane upon a flash of UV-A light. This effect is quickly reversed after the termination of photostimulation or by irradiation with blue light, permitting the generation of oscillation patterns. Both protein kinase C and Munc13 can thus be put under optical control. PhoDAGs control vesicle release in excitable cells, such as mouse pancreatic islets and hippocampal neurons, and modulate synaptic transmission in Caenorhabditis elegans. As such, the PhoDAGs afford an unprecedented degree of spatiotemporal control and are broadly applicable tools to study DAG signaling
FindFoci: a focus detection algorithm with automated parameter training that closely matches human assignments, reduces human inconsistencies and increases speed of analysis
Accurate and reproducible quantification of the accumulation of proteins into foci in cells is essential for data interpretation and for biological inferences. To improve reproducibility, much emphasis has been placed on the preparation of samples, but less attention has been given to reporting and standardizing the quantification of foci. The current standard to quantitate foci in open-source software is to manually determine a range of parameters based on the outcome of one or a few representative images and then apply the parameter combination to the analysis of a larger dataset. Here, we demonstrate the power and utility of using machine learning to train a new algorithm (FindFoci) to determine optimal parameters. FindFoci closely matches human assignments and allows rapid automated exploration of parameter space. Thus, individuals can train the algorithm to mirror their own assignments and then automate focus counting using the same parameters across a large number of images. Using the training algorithm to match human assignments of foci, we demonstrate that applying an optimal parameter combination from a single image is not broadly applicable to analysis of other images scored by the same experimenter or by other experimenters. Our analysis thus reveals wide variation in human assignment of foci and their quantification. To overcome this, we developed training on multiple images, which reduces the inconsistency of using a single or a few images to set parameters for focus detection. FindFoci is provided as an open-source plugin for ImageJ
Centralization of Esophageal Cancer Surgery: Does It Improve Clinical Outcome?
Background: The volume-outcome relationship for complex surgical procedures has been extensively studied. Most studies are based on administrative data and use in-hospital mortality as the sole outcome measure. It is still unknown if concentration of these procedures leads to improvement of clinical outcome. The aim of our study was to audit the process and effect of centralizing oesophageal resections for cancer by using detailed clinical data. Methods: From January 1990 until December 2004, 555 esophagectomies for cancer were performed in 11 hospitals in the region of the Comprehensive Cancer Center West (CCCW); 342 patients were operated on before and 213 patients after the introduction of a centralization project. In this project patients were referred to the hospitals which showed superior outcomes in a regional audit. In this audit patient, tumor, and operative details as well as clinical outcome were compared between hospitals. The outcome of both cohorts, patients operated on before and after the start of the project, were evaluated. Results: Despite the more severe comorbidity of the patient group, outcome improved after centralizing esophageal resections. Along with a reduction in postoperative morbidity and length of stay, mortality fell from 12% to 4% and survival improved significantly (P = 0.001). The hospitals with the highest procedural volume showed the biggest improvement in outcome. Conclusion: Volume is an important determinant of quality of care in esophageal cancer surgery. Referral of patients with esophageal cancer to surgical units with adequate experience and superior outcomes (outcome-based referral) improves quality of care
A fractal dimension for measures via persistent homology
We use persistent homology in order to define a family of fractal dimensions,
denoted for each homological dimension
, assigned to a probability measure on a metric space. The case
of -dimensional homology () relates to work by Michael J Steele (1988)
studying the total length of a minimal spanning tree on a random sampling of
points. Indeed, if is supported on a compact subset of Euclidean space
for , then Steele's work implies that
if the absolutely continuous part of
has positive mass, and otherwise .
Experiments suggest that similar results may be true for higher-dimensional
homology , though this is an open question. Our fractal dimension is
defined by considering a limit, as the number of points goes to infinity,
of the total sum of the -dimensional persistent homology interval lengths
for random points selected from in an i.i.d. fashion. To some
measures we are able to assign a finer invariant, a curve measuring the
limiting distribution of persistent homology interval lengths as the number of
points goes to infinity. We prove this limiting curve exists in the case of
-dimensional homology when is the uniform distribution over the unit
interval, and conjecture that it exists when is the rescaled probability
measure for a compact set in Euclidean space with positive Lebesgue measure
UK adults' implicit and explicit attitudes towards obesity: a cross-sectional study.
Background: Anti-fat attitudes may lead to stigmatisation of and lowered self-esteem in obese people. Examining anti-fat attitudes is warranted given that there is an association with anti-fat behaviours. Previous studies, mainly outside the UK, have demonstrated that anti-fat attitudes are increasing over time. Methods: The study was cross-sectional with a sample of 2380 participants (74.2 % female; aged 18–65 years). In an online survey participants reported demographic characteristics and completed a range of implicit and explicit measures of obesity related attitudes. Results: Perceptions of obesity were more negative than reported in previously. Main effects indicated more negative perceptions in males, younger respondents and more frequent exercisers. Attitudes about obesity differed in relation to weight category, and in general were more positive in obese than non-obese respondents. Conclusions: This is the first study to demonstrate anti-fat attitudes across different sections of the UK population. As such, this study provides the first indication of the prevalence of anti-fat attitudes in UK adults. Interventions to modify these attitudes could target specific groups of individuals with more negative perceptions as identified here. Future work would be useful that increases understanding of both implicit and explicit attitudes towards obesity
Colorectal cancer after a negative Haemoccult II® test and programme sensitivity after a first round of screening: the experience of the Department of Calvados (France)
Colorectal cancers emerging after a negative Haemoccult II® are described in the context of a first round of mass screening in the Department of Calvados (France), from April 1991 to the end of December 1994. People with a cancer occurring after a negative test until 31 December 1995 were identified by a local cancer registry. Incidence was calculated and the programme sensitivity was estimated. The incidence of cancer emerging after a negative test was 57.7 per 100 000, i.e. half of the calculated incidence in the reference group (141.6 per 100 000). These cancers did not differ from those of either the non-responder or reference groups, in particular for the stage of extension. The programme sensitivity was globally higher than that estimated in European trials: 77.2, 66.3 and 55.9%, 1, 2 and 3 years after the test respectively. Programme sensitivity was higher for distal colon cancer 1 year after the test, which is probably due to the relatively slow growth of this subsite. © 1999 Cancer Research Campaig
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