2,532 research outputs found
Pulmonary Capillary Recruitment and Distention in Mammalian Lungs: Species Similarities
Pulmonary arterial pressure rises minimally during exercise. The pulmonary microcirculation accommodates increasing blood flow via recruitment of pulmonary capillaries and, at higher flows, by distention of already perfused capillaries. The flow transition range between recruitment and distention has not been studied or compared across mammalian species, including humans. We hypothesised that the range would be similar. Functional pulmonary capillary surface area (FCSA) can be estimated using validated metabolic techniques. We reviewed data from previous studies in three mammalian species (perfused rabbit lungs and dog lung lobes, and exercising humans) and generated blood flow-FCSA curves over a range of flows. We noted where the curves diverged from the theoretical line of pure recruitment (Recruitment) and determined the flow where the curve slope equalled 50% that of Recruitment, or equalled that of a theoretical curve representing full capillary distention (Distention). The three mammalian species have similar flow ranges for the transition from predominantly recruitment to predominantly distention, with dogs having the highest transition point. Within the physiological range of most daily activity, the species are similar and accommodate increasing blood flow mainly via recruitment, with progressive distention at higher flows. This is highly relevant to pulmonary physiology during exercise
The Paradox of Pulmonary Vascular Resistance: Restoration of Pulmonary Capillary Recruitment as a \u3ci\u3eSine Qua Non\u3c/i\u3e for True Therapeutic Success in Pulmonary Arterial Hypertension
Exercise-induced increases in pulmonary blood flow normally increase pulmonary arterial pressure only minimally, largely due to a reserve of pulmonary capillaries that are available for recruitment to carry the flow. In pulmonary arterial hypertension, due to precapillary arteriolar obstruction, such recruitment is greatly reduced. In exercising pulmonary arterial hypertension patients, pulmonary arterial pressure remains high and may even increase further. Current pulmonary arterial hypertension therapies, acting principally as vasodilators, decrease calculated pulmonary vascular resistance by increasing pulmonary blood flow but have a minimal effect in lowering pulmonary arterial pressure and do not restore significant capillary recruitment. Novel pulmonary arterial hypertension therapies that have mainly antiproliferative properties are being developed to try and diminish proliferative cellular obstruction in precapillary arterioles. If effective, those agents should restore capillary recruitment and, during exercise testing, pulmonary arterial pressure should remain low despite increasing pulmonary blood flow. The effectiveness of every novel therapy for pulmonary arterial hypertension should be evaluated not only at rest, but with measurement of exercise pulmonary hemodynamics during clinical trials
Expression vectors for Neurospora crassa and expression of a bovine preprochymosin cDNA
The filamentous fungi, owing to their ability to secrete high levels of proteins, are attractive organisms for the expression and secretion of heterologous proteins of commercial and medical value. We report the construction of three expression vectors for the production of heterologous proteins in Neurospora crassa and demonstrate their utility by expression of a bovine preprochymosin cDNA and secretion of processed, enzymatically active bovine chymosin
SPIRITS 15c and SPIRITS 14buu: Two Obscured Supernovae in the Nearby Star-Forming Galaxy IC 2163
SPIRITS---SPitzer InfraRed Intensive Transients Survey---is an ongoing survey
of nearby galaxies searching for infrared (IR) transients with Spitzer/IRAC. We
present the discovery and follow-up observations of one of our most luminous
( mag, Vega) and red (
mag) transients, SPIRITS 15c. The transient was detected in a dusty spiral arm
of IC 2163 ( Mpc). Pre-discovery ground-based imaging revealed an
associated, shorter-duration transient in the optical and near-IR (NIR). NIR
spectroscopy showed a broad ( km s), double-peaked
emission line of He I at m, indicating an explosive origin. The NIR
spectrum of SPIRITS 15c is similar to that of the Type IIb SN 2011dh at a phase
of days. Assuming mag of extinction in SPIRITS 15c
provides a good match between their optical light curves. The IR light curves
and the extreme color cannot be explained using only a standard
extinction law. Another luminous ( mag) event, SPIRITS
14buu, was serendipitously discovered in the same galaxy. The source displays
an optical plateau lasting days, and we suggest a scenario similar
to the low-luminosity Type IIP SN 2005cs obscured by mag.
Other classes of IR-luminous transients can likely be ruled out in both cases.
If both events are indeed SNe, this may suggest of nearby
core-collapse SNe are missed by currently operating optical surveys.Comment: 19 pages, 7 Figures, 4 Table
Bilateral Central Giant Cell Granulomas of the Mandible in An Eight Year-Old Girl with Noonan Syndrome (Noonan-Like/Multiple Giant Cell Lesions Syndrome)
A number of conditions can present with lesions that histologically are indistinguishable from the central giant cell granuloma (CGCG) of bone, including brown tumors of hyperparathyroidism, cherubism, and, less commonly, a number of inherited syndromes.
We report a case of an eight-year girl who presented with bilateral CGCGs of the
posterior mandible. Characteristic facial features, reported increased post-operative bleeding and history of pulmonary stenosis led us to suspect a diagnosis of Noonan syndrome. A medical geneticist confirmed this on further evaluation.
This case report will discuss the salient features of this diagnosis
Spectroscopic Discovery of the Broad-Lined Type Ic Supernova 2010bh Associated with the Low-Redshift GRB 100316D
We present the spectroscopic discovery of a broad-lined Type Ic supernova (SN
2010bh) associated with the nearby long-duration gamma-ray burst (GRB) 100316D.
At z = 0.0593, this is the third-nearest GRB-SN. Nightly optical spectra
obtained with the Magellan telescopes during the first week after explosion
reveal the gradual emergence of very broad spectral features superposed on a
blue continuum. The supernova features are typical of broad-lined SNe Ic and
are generally consistent with previous supernovae associated with low-redshift
GRBs. However, the inferred velocities of SN 2010bh at 21 days after explosion
are a factor of ~2 times larger than those of the prototypical SN 1998bw at
similar epochs, with v ~ 26,000 km/s, indicating a larger explosion energy or a
different ejecta structure. A near-infrared spectrum taken 13.8 days after
explosion shows no strong evidence for He I at 1.083 microns, implying that the
progenitor was largely stripped of its helium envelope. The host galaxy is of
low luminosity (M_R ~ -18.5 mag) and low metallicity (Z < 0.4 Z_solar), similar
to the hosts of other low-redshift GRB-SNe.Comment: 6 pages, 4 figures, 1 table, submitted to ApJ Letter
Induction heating coupler
An induction heating device includes a handle having a hollow interior and two opposite ends, a wrist connected to one end of the handle, a U-shaped pole piece having two spaced apart ends, a tank circuit including an induction coil wrapped around the pole piece and a capacitor connected to the induction coil, a head connected to the wrist and including a housing for receiving the U-shaped pole piece, the two spaced apart ends of the pole piece extending outwardely beyond the housing, and a power source connected to the tank circuit. When the tank circuit is energized and a susceptor is placed in juxtaposition to the ends of the U-shaped pole piece, the susceptor is heated by induction heating due to magnetic flux passing between the two ends of the pole piece
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Mental health in UK Biobank - development, implementation and results from an online questionnaire completed by 157 366 participants: a reanalysis
Background
UK Biobank is a well-characterised cohort of over 500 000 participants including genetics, environmental data and imaging. An online mental health questionnaire was designed for UK Biobank participants to expand its potential.
Aims
Describe the development, implementation and results of this questionnaire.
Method
An expert working group designed the questionnaire, using established measures where possible, and consulting a patient group. Operational criteria were agreed for defining likely disorder and risk states, including lifetime depression, mania/hypomania, generalised anxiety disorder, unusual experiences and self-harm, and current post-traumatic stress and hazardous/harmful alcohol use.
Results
A total of 157 366 completed online questionnaires were available by August 2017. Participants were aged 45–82 (53% were ≥65 years) and 57% women. Comparison of self-reported diagnosed mental disorder with a contemporary study shows a similar prevalence, despite respondents being of higher average socioeconomic status. Lifetime depression was a common finding, with 24% (37 434) of participants meeting criteria and current hazardous/harmful alcohol use criteria were met by 21% (32 602), whereas other criteria were met by less than 8% of the participants. There was extensive comorbidity among the syndromes. Mental disorders were associated with a high neuroticism score, adverse life events and long-term illness; addiction and bipolar affective disorder in particular were associated with measures of deprivation.
Conclusions
The UK Biobank questionnaire represents a very large mental health survey in itself, and the results presented here show high face validity, although caution is needed because of selection bias. Built into UK Biobank, these data intersect with other health data to offer unparalleled potential for crosscutting biomedical research involving mental health
Common genetic variants influence human subcortical brain structures
The highly complex structure of the human brain is strongly shaped by genetic influences. Subcortical brain regions form circuits with cortical areas to coordinate movement, learning, memory and motivation, and altered circuits can lead to abnormal behaviour and disease. To investigate how common genetic variants affect the structure of these brain regions, here we conduct genome-wide association studies of the volumes of seven subcortical regions and the intracranial volume derived from magnetic resonance images of 30,717 individuals from 50 cohorts. We identify five novel genetic variants influencing the volumes of the putamen and caudate nucleus. We also find stronger evidence for three loci with previously established influences on hippocampal volume and intracranial volume. These variants show specific volumetric effects on brain structures rather than global effects across structures. The strongest effects were found for the putamen, where a novel intergenic locus with replicable influence on volume (rs945270; P = 1.08 × 10(-33); 0.52% variance explained) showed evidence of altering the expression of the KTN1 gene in both brain and blood tissue. Variants influencing putamen volume clustered near developmental genes that regulate apoptosis, axon guidance and vesicle transport. Identification of these genetic variants provides insight into the causes of variability in human brain development, and may help to determine mechanisms of neuropsychiatric dysfunction
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