Shining new light on mammalian diving physiology using wearable near-infrared spectroscopy

Investigation of marine mammal dive-by-dive blood distribution and oxygenation has been limited by a lack of non-invasive technology for use in freely diving animals. Here, we developed a non-invasive near-infrared spectroscopy (NIRS) device to measure relative changes in blood volume and haemoglobin oxygenation continuously in the blubber and brain of voluntarily diving harbour seals. Our results show that seals routinely exhibit preparatory peripheral vasoconstriction accompanied by increased cerebral blood volume approximately 15 s before submersion. These anticipatory adjustments confirm that blood redistribution in seals is under some degree of cognitive control that precedes the mammalian dive response. Seals also routinely increase cerebral oxygenation at a consistent time during each dive, despite a lack of access to ambient air. We suggest that this frequent and reproducible reoxygenation pattern, without access to ambient air, is underpinned by previously unrecognised changes in cerebral drainage. The ability to track blood volume and oxygenation in different tissues using NIRS will facilitate a more accurate understanding of physiological plasticity in diving animals in an increasingly disturbed and exploited environment

Concomitant occurrence of FXTAS and clinically defined sporadic inclusion body myositis: report of two cases.

This report describes unique presentations of inclusion body myositis (IBM) in two unrelated patients, one male and one female, with genetically and histologically confirmed fragile X-associated tremor/ataxia syndrome (FXTAS). We summarize overlapping symptoms between two disorders, clinical course, and histopathological analyses of the two patients with FXTAS and sporadic IBM, clinically defined per diagnostic criteria of the European Neuromuscular Centre. In case 1, a post-mortem analysis of available brain and muscle tissues is also described. Histopathological features (rimmed vacuoles) consistent with clinically defined IBM were detected in both presented cases. Postmortem testing in case 1 revealed the presence of an FMR1 premutation allele of 60 CGG repeats in both brain and skeletal muscle samples. Case 2 was a premutation carrier with 71 CGG repeats who had a son with FXS. Given that FXTAS is associated with immune-mediated disorders among premutation carriers, it is likely that the pathogeneses of IBM and FXTAS are linked. This is, to our knowledge, the first report of these two conditions presenting together, which expands our understanding of clinical symptoms and unusual presentations in patients with FXTAS. Following detection of a premutation allele of the FMR1 gene, FXTAS patients with severe muscle pain should be assessed for IBM

The Relationship Between Physical Characteristics and Maximal Strength in Men Practicing the Back Squat, the Bench Press and the Deadlift

International Journal of Exercise Science 13(4): 281-297, 2020. This study was designed to quantify the relationships between physical characteristics and maximal strength in the back squat, the bench press and the deadlift on powerlifters and football players.Eighteen male junior drug-tested classic powerlifters and seventeen NCAA Division II American football players’ anthropometric measurements were taken to compare them with maximal strength results from either a powerlifting meet or testing from their supervised strength and conditioning program. Pearson’s bivariate correlations analysis revealed (statistical significance was set at

Red Flags in Family History and Auscultations that may require 12-Lead ECG when Screening Athletes

The main components of pre-participation physical exams (PPE) at the NCAA Division II level include a thorough medical history and physical evaluation (AHA). “Red flags” for risk on the PPE and medical history include, but are not limited to, heart murmur, diagnosed enlarged heart in a family member, unexplained chest pain, and complaints of skipped heartbeats. The purpose of this investigation was to determine if the use of 12-lead ECG for the PPE would reveal further red flags specific to cardiac abnormalities. Twelve-lead electrocardiogram (ECG) was performed on all new athletes at Tarleton State University during the Summer and Fall 2012 (N=200). Twelve-lead ECGs were reviewed and analyzed by the lab director and attending physician. Upon completion of the PPE, medical history, and ECG, five athletes needed follow-up based on PPE and 12-lead ECG. Reasons for initial concern were the previously stated “red flags” as well as abnormal ECG readings. The abnormal ECG readings included left ventricular hypertrophy (LVH), incomplete right bundle branch block (IRBBB), sinus arrhythmia, and right atrial enlargement (RAE). LVH, IRBB, and sinus arrhythmia were all found to be normal training induced adaptations, however RAE is a non-training induced cardiac abnormality. Of those five, all of them had some type of cardiac adaptation, but one of them presented with RAE. The athlete was an 18-year old male, 64.5” tall, 116 pounds, and in his first year of collegiate cross-country athletics. His HR was 81bpm and blood pressure was 122/72 mmHg. His grandmother was diagnosed with an enlarged heart. The clearing physician, an orthopedic doctor, found only training induced abnormalities in all five athletes. All five athletes were cleared for competition. Endurance athletes often have abnormal ECG readings as a result of training induced abnormalities. In the present investigation, an athlete with RAE competed for an entire cross-country season without any issues or complaints. Physicians trained in reading ECGs should be responsible for clearing athletes for participation. In this case, right atrial enlargement appeared in the ECG, yet the orthopedic doctor did not request follow up tests. Physicians who are versed in exercise training induced changes that might be classified as normal or abnormal should be the final step in clearing athletes for competition

Towards 3D in vitro models for the study of cardiovascular tissues and disease

The field of tissue engineering is developing biomimetic biomaterial scaffolds which are showing increasing therapeutic potential for the repair of cardiovascular tissues. However, a major opportunity exists to use them as 3D in vitro models for the study of cardiovascular tissues and disease in addition to drug development and testing. These in vitro models can span the gap between 2D culture and in vivo testing thus reducing cost, time and the ethical burden of current approaches. This review outlines the progress to date and requirements for the development of ideal in vitro 3D models for blood vessels, heart valves and myocardial tissue

Alterations to the Gastrointestinal Microbiome Associated with Methamphetamine Use among Young Men who have Sex with Men.

Methamphetamine (MA) use is a major public health problem in the United States, especially among people living with HIV (PLWH). Many MA-induced neurotoxic effects are mediated by inflammation and gut microbiota may play a role in this process, yet the effects of MA on the microbiome have not been adequately explored. Therefore, we performed 16S rRNA gene sequencing on rectal swab samples from 381 men who have sex with men, 48% of whom were PLWH and 41% of whom used MA. We compared microbiome composition between MA users and non-users while testing for potential interactions with HIV and controlling for numerous confounders using inverse probability of treatment weighting. We found that MA use explained significant variation in overall composition (R2 = 0.005, p = 0.008) and was associated with elevated Finegoldia, Parvimonas, Peptoniphilus, and Porphyromonas and reduced Butyricicoccus and Faecalibacterium, among others. Genera including Actinomyces and Streptobacillus interacted with HIV status, such that they were increased in HIV+ MA users. Finegoldia and Peptoniphilus increased with increasing frequency of MA use, among others. In summary, MA use was associated with a microbial imbalance favoring pro-inflammatory bacteria, including some with neuroactive potential and others that have previously been associated with poor HIV outcomes

GALEX, Optical and IR Light Curves of MQ Dra: UV Excesses at Low Accretion Rates

Ultraviolet light curves constructed from NUV and FUV detectors on GALEX reveal large amplitude variations during the orbital period of the Low Accretion Rate Polar MQ Dra (SDSSJ1553+55). This unexpected variation from a UV source is similar to that seen and discussed in the Polar EF Eri during its low state of accretion, even though the accretion rate in MQ Dra is an order of magnitude lower than even the low state of EF Eri. The similarity in phasing of the UV and optical light curves in MQ Dra imply a similar location for the source of light. We explore the possibilities of hot spots and cyclotron emission with simple models fit to the UV, optical and IR light curves of MQ Dra. To match the GALEX light curves with a single temperature circular hot spot requires different sizes of spots for the NUV and FUV, while a cyclotron model that can produce the optical harmonics with a magnetic field near 60 MG requires multipoles with fields > 200 MG to match the UV fluxes.Comment: accepted for ApJ; 15 pages, 7 tables, 8 fig

Low State, Phase-Resolved IR Spectroscopy of VV Puppis

We present phase-resolved low resolution $JHK$ and higher resolution $K$-band spectroscopy of the polar VV Pup. All observations were obtained when VV Pup was in a low accretion state having a K magnitude near 15. The low resolution observations reveal cyclotron emission in the $J$ band during some phases, consistent with an origin near the active 30.5 MG pole on the white dwarf. The secondary in VV Pup appears to be a normal M7V star and we find that the $H$ and $K$ band fluxes are entirely due to this star at all orbital phases during the low accretion state. We use our higher resolution Keck spectroscopy to produce the first $K$-band radial velocity curve for VV Pup. Our orbital solution yields $K_2$=414$\pm27$ km sec$^{-1}$ and leads to mass estimates of M$_1$=0.73$\pm$0.05 M$_{\odot}$ and M$_2$=0.10$\pm$0.02 M$_{\odot}$. We find that the mass accretion rates during the normal low states of the polars VV Pup, EF Eri, and EQ Cet are near 10$^{-13}$ M$_{\odot}$ yr$^{-1}$. The fact that \.M is not zero in low state polars indicates active secondary stars in these binary systems, including the sub-stellar donor star present in EF Eri.Comment: Accepted in Astronomical Journal 5 figure

Cyclotron modeling phase-resolved infrared spectroscopy of polars I: EF Eridani

We present phase-resolved low resolution infrared spectra of the polar EF Eridani obtained over a period of 2 years with SPEX on the IRTF. The spectra, covering the wavelength range 0.8 to 2.4 microns, are dominated by cyclotron emission at all phases. We use a ``Constant Lambda'' prescription to attempt to model the changing cyclotron features seen in the spectra. A single cyclotron emission component with B = 12.6 MG, and a plasma temperature of kT = 5.0 keV, does a reasonable job in matching the features seen in the H and K bands, but fails to completely reproduce the morphology shortward of 1.6 microns. We find that a two component model, where both components have similar properties, but whose contributions differ with viewing geometry, provides an excellent fit to the data. We discuss the implications of our models and compare them with previously published results. In addition, we show that a cyclotron model with similar properties to those used for modeling the infrared spectra, but with a field strength of B = 115 MG, can explain the GALEX observations of EF Eri.Comment: 25 pages, 5 figures, to appear in Ap

Can Ultrasound Be Used to Improve the Palpation Skills of Physicians in Training? A Prospective Study

BackgroundAccurate diagnosis of musculoskeletal disorders relies heavily on the physical examination, including accurate palpation of musculoskeletal structures. The literature suggests that there has been a deterioration of physical examination skills among medical students and residents, in part due to increased reliance on advanced imaging. It has been shown that knowledge of musculoskeletal anatomy and physical examination skills improve with the use of ultrasound; however, the literature is limited.ObjectiveTo determine whether ultrasound can improve the ability of physicians in training (residents) to palpate the long head of the biceps tendon (LHBT) in the bicipital groove.DesignProspective study design.SettingTertiary care center.ParticipantsTen physical medicine and rehabilitation residents served as subjects. Exclusion criteria included the presence of any condition that precluded their ability to palpate. Three volunteers were used as models. Model exclusion criteria included anything that distorted normal shoulder anatomy or inhibited examiner palpation. Three investigators with experience performing diagnostic musculoskeletal ultrasound were used to confirm palpation attempts.MethodsSubjects attempted to palpate the LHBT bilaterally in the bicipital groove of each model. Investigators assessed the accuracy of the palpation attempt using real‐time ultrasonography. Subjects participated in a 30‐minute ultrasound‐assisted training session learning how to palpate the LHBT in the bicipital groove with ultrasound confirmation. After the ultrasound training session, subjects again attempted to palpate the LHBT in the bicipital groove of each model with investigator confirmation.Main Outcome MeasurementsLHBT palpation accuracy rates preintervention versus postintervention.ResultsPretraining LHBT palpation accuracy was 20% (12/60 attempts). Post‐ultrasound training session accuracy was 51.7% (31/60 attempts; P ≤ .001).ConclusionsOur findings demonstrate that palpation accuracy improves after ultrasound assisted LHBT palpation training. These data suggest that the use of ultrasound may be beneficial when teaching musculoskeletal palpation skills to health care professionals.Level of EvidenceIIPeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146948/1/pmr2730.pd