Membranes by the Numbers

Many of the most important processes in cells take place on and across membranes. With the rise of an impressive array of powerful quantitative methods for characterizing these membranes, it is an opportune time to reflect on the structure and function of membranes from the point of view of biological numeracy. To that end, in this article, I review the quantitative parameters that characterize the mechanical, electrical and transport properties of membranes and carry out a number of corresponding order of magnitude estimates that help us understand the values of those parameters.Comment: 27 pages, 12 figure

Referral of patients with depression to mental health care by Dutch general practitioners: an observational study

<p>Abstract</p> <p>Background</p> <p>Depression is a common illness, often treated in primary care. Guidelines provide recommendations for referral to mental health care. Several studies investigated determinants of referral, none investigated guideline criteria as possible determinants.</p> <p>We wanted to evaluate general practitioner's referral of depressed patients to mental health care and to what extent this is in agreement with (Dutch) guideline recommendations.</p> <p>Methods</p> <p>We used data of primary care respondents from the Netherlands Study of Depression and Anxiety with major depressive disorder in the past year (n = 478). We excluded respondents with missing data (n = 134). Referral data was collected from electronic patient files between 1 year before and after baseline and self report at baseline and 1-year follow-up. Logistic regression was used to describe association between guideline referral criteria (e.g. perceived need for psychotherapy, suicide risk, severe/chronic depression, antidepressant therapy failure) and referral.</p> <p>Results</p> <p>A high 58% of depressed patients were referred. Younger patients, those with suicidal tendency, chronic depression or perceived need for psychotherapy were referred more often. Patients who had used ≥2 antidepressants or with chronic depression were more often referred to secondary care. Referred respondents met on average more guideline criteria for referral. However, only 8-11% of variance was explained.</p> <p>Conclusion</p> <p>The majority of depressed patients were referred to mental health care. General practitioners take guideline criteria into account in decision making for referral of depressed patients to mental health care. However, other factors play a part, considering the small percentage of variance explained. Further research is necessary to investigate this.</p

Non-invasive monitoring of Streptococcus pyogenes vaccine efficacy using biophotonic imaging.

Streptococcus pyogenes infection of the nasopharynx represents a key step in the pathogenic cycle of this organism and a major focus for vaccine development, requiring robust models to facilitate the screening of potentially protective antigens. One antigen that may be an important target for vaccination is the chemokine protease, SpyCEP, which is cell surface-associated and plays a role in pathogenesis. Biophotonic imaging (BPI) can non-invasively characterize the spatial location and abundance of bioluminescent bacteria in vivo. We have developed a bioluminescent derivative of a pharyngeal S. pyogenes strain by transformation of an emm75 clinical isolate with the luxABCDE operon. Evaluation of isogenic recombinant strains in vitro and in vivo confirmed that bioluminescence conferred a growth deficit that manifests as a fitness cost during infection. Notwithstanding this, bioluminescence expression permitted non-invasive longitudinal quantitation of S. pyogenes within the murine nasopharynx albeit with a detection limit corresponding to approximately 10(5) bacterial colony forming units (CFU) in this region. Vaccination of mice with heat killed streptococci, or with SpyCEP led to a specific IgG response in the serum. BPI demonstrated that both vaccine candidates reduced S. pyogenes bioluminescence emission over the course of nasopharyngeal infection. The work suggests the potential for BPI to be used in the non-invasive longitudinal evaluation of potential S. pyogenes vaccines

Characteristics of general practice care: What do senior citizens value? A qualitative study

<p>Abstract</p> <p>Background</p> <p>In view of the increasing number of senior citizens in our society who are likely to consult their GP with age-related health problems, it is important to identify and understand the preferences of this group in relation to the non-medical attributes of GP care. The aim of this study is to improve our understanding about preferences of this group of patients in relation to non-medical attributes of primary health care. This may help to develop strategies to improve the quality of care that senior citizens receive from their GP.</p> <p>Methods</p> <p>Semi-structured interviews (N = 13) with senior citizens (65-91 years) in a judgement sample were recorded and transcribed verbatim. The analysis was conducted according to qualitative research methodology and the frame work method.</p> <p>Results</p> <p>Continuity of care providers, i.e. GP and practice nurses, GPs' expertise, trust, free choice of GP and a kind open attitude were highly valued. Accessibility by phone did not meet the expectations of the interviewees. The interviewees had difficulties with the GP out-of-office hours services. Spontaneous home visits were appreciated by some, but rejected by others. They preferred to receive verbal information rather than collecting information from leaflets. Distance to the practice and continuity of caregiver seemed to conflict for respondents.</p> <p>Conclusions</p> <p>Preferences change in the process of ageing and growing health problems. GPs and their co-workers should be also aware of the changing needs of the elderly regarding non-medical attributes of GP care. Meeting their needs regarding non-medical attributes of primary health care is important to improve the quality of care.</p

X-Ray Spectroscopy of Stars

(abridged) Non-degenerate stars of essentially all spectral classes are soft X-ray sources. Low-mass stars on the cooler part of the main sequence and their pre-main sequence predecessors define the dominant stellar population in the galaxy by number. Their X-ray spectra are reminiscent, in the broadest sense, of X-ray spectra from the solar corona. X-ray emission from cool stars is indeed ascribed to magnetically trapped hot gas analogous to the solar coronal plasma. Coronal structure, its thermal stratification and geometric extent can be interpreted based on various spectral diagnostics. New features have been identified in pre-main sequence stars; some of these may be related to accretion shocks on the stellar surface, fluorescence on circumstellar disks due to X-ray irradiation, or shock heating in stellar outflows. Massive, hot stars clearly dominate the interaction with the galactic interstellar medium: they are the main sources of ionizing radiation, mechanical energy and chemical enrichment in galaxies. High-energy emission permits to probe some of the most important processes at work in these stars, and put constraints on their most peculiar feature: the stellar wind. Here, we review recent advances in our understanding of cool and hot stars through the study of X-ray spectra, in particular high-resolution spectra now available from XMM-Newton and Chandra. We address issues related to coronal structure, flares, the composition of coronal plasma, X-ray production in accretion streams and outflows, X-rays from single OB-type stars, massive binaries, magnetic hot objects and evolved WR stars.Comment: accepted for Astron. Astrophys. Rev., 98 journal pages, 30 figures (partly multiple); some corrections made after proof stag

Does the attention General Practitioners pay to their patients' mental health problems add to their workload? A cross sectional national survey

BACKGROUND: The extra workload induced by patients with mental health problems may sometimes cause GPs to be reluctant to become involved in mental health care. It is known that dealing with patients' mental health problems is more time consuming in specific situations such as in consultations. But it is unclear if GPs who are more often involved in patients' mental health problems, have a higher workload than other GPs. Therefore we investigated the following: Is the attention GPs pay to their patients' mental health problems related to their subjective and objective workload? METHODS: Secondary analyses were made using data from the Second Dutch National Survey of General Practice, a cross sectional study conducted in the Netherlands in 2000–2002. A nationally representative selection of 195 GPs from 104 general practices participated in this National Survey. Data from: 1) a GP questionnaire; 2) a detailed log of the GP's time use during a week and; 3) an electronic medical registration system, including all patients' contacts during a year, were used. Multiple regression analyses were conducted with the GP's workload as an outcome measure, and the GP's attention for mental health problems as a predictor. GP, patient, and practice characteristics were included in analyses as potential confounders. RESULTS: Results show that GPs with a broader perception of their role towards mental health care do not have more working hours or patient contacts than GPs with a more limited perception of their role. Neither are they more exhausted or dissatisfied with the available time. Also the number of patient contacts in which a psychological or social diagnosis is made is not related to the GP's objective or subjective workload. CONCLUSION: The GP's attention for a patient's mental health problems is not related to their workload. The GP's extra workload when dealing in a consultation with patients' mental health problems, as is demonstrated in earlier research, is not automatically translated into a higher overall workload. This study does not confirm GPs' complaints that mental health care is one of the components of their job that consumes a lot of their time and energy. Several explanations for these results are discussed

Variation in the Male Pheromones and Mating Success of Wild Caught Drosophila melanogaster

Drosophila melanogaster males express two primary cuticular hydrocarbons (male-predominant hydrocarbons). These act as sex pheromones by influencing female receptivity to mating. The relative quantities of these hydrocarbons vary widely among natural populations and can contribute to variation in mating success. We tested four isofemale lines collected from a wild population to assess the effect of intrapopulation variation in male-predominant hydrocarbons on mating success. The receptivity of laboratory females to males of the four wild-caught lines varied significantly, but not consistently in the direction predicted by variation in male-predominant hydrocarbons. Receptivity of the wild-caught females to laboratory males also varied significantly, but females from lines with male-predominant hydrocarbon profiles closer to a more cosmopolitan one did not show a correspondingly strong mating bias toward a cosmopolitan male. Among wild-caught lines, the male-specific ejaculatory bulb lipid, cis-vaccenyl acetate, varied more than two-fold, but was not associated with variation in male mating success. We observed a strong inverse relationship between the receptivity of wild-caught females and the mating success of males from their own lines, when tested with laboratory flies of the opposite sex

Primary Raynaud's phenomenon in an infant: a case report and review of literature

Raynaud's phenomenon (RP) is an extremely unusual finding in early infancy. In the present report we describe a one-month-old previously healthy male infant who presented with unilateral acrocyanosis. Although infantile acrocyanosis is known to be a benign and self-resolving condition, it is generally bilateral and symmetric. The unilateral nature of the acrocyanosis was an atypical finding in this infant. Consequently, he was closely monitored to evaluate the progression of his acrocyanosis. Based on his benign clinical course and failure to demonstrate other etiologies contributing to his acrocyanosis, he was diagnosed to have primary RP. Due to the rarity of RP in children, we review the progress in understanding the pathophysiology, epidemiology and management of RP and additionally discuss the differential diagnosis of unilateral and bilateral acrocyanosis in infants