Validation of a New NIRS Method for Measuring Muscle Oxygenation During Rhythmic Handgrip Exercise

Near infrared spectroscopy (NIRS) is commonly used to measure muscle oxygenation during exercise and recovery. Current NIRS algorithms do not account for variation in water content and optical pathlength during exercise. The current effort attempts to validate a newly developed NIRS algorithm during rhythmic handgrip exercise and recovery. Six female subjects, aver age 28 +/- 6 yrs, participated in the study. A venous catheter was placed in the retrograde direction in the antecubital space. A NIRS sensor with 30 mm source-detector separation was placed on the flexor digitorum profundus. Subjects performed two 5-min bouts of rhythmic handgrip exercise (2 s contraction/1 s relaxation) at 15% and 30% of maximal voluntary contraction. Venous blood was sampled before each bout, during the last minute of exercise, and after 5 minutes of recovery. Venous oxygen saturation (SvO2) was measured with a I-stat CG-4+ cartridge. Spectra were collected between 700-900 nm. A modified Beer's Law formula was used to calculate the absolute concentration of oxyhemoglobin (HbO2), deoxyhemoglobin (Hb) and water, as well as effective pathlength for each spectrum. Muscle oxygen saturation (SmO2) was calculated from the HbO2 and Hb results. The correlation between SvO2 and SmO2 was determined. Optical pathlength and water varied significantly during each exercise bout, with pathlength increasing approximately 20% and water increasing about 2%. R2 between blood and muscle SO2 was found to be 0.74, the figure shows the relationship over SvO2 values between 22% and 82%. The NIRS measurement was, on average, 6% lower than the blood measurement. It was concluded that pathlength changes during exercise because muscle contraction causes variation in optical scattering. Water concentration also changes, but only slightly. A new NIRS algorithm which accounts for exercise-induced variation in water and pathlength provided an accurate assessment of muscle oxygen saturation before, during and after exercise

Sensory and Quasi-Sensory Experiences of the Deceased in Bereavement : An Interdisciplinary and Integrative Review

Bereaved people often report having sensory and quasi-sensory experiences of the deceased (SED), and there is an ongoing debate over whether SED are associated with pathology, such as grief complications. Research into these experiences has been conducted in various disciplines, including psychiatry, psychology, and anthropology, without much crossover. This review brings these areas of research together, drawing on the expertise of an interdisciplinary working group formed as part of the International Consortium for Hallucination Research (ICHR). It examines existing evidence on the phenomenology, associated factors, and impact of SED, including the role of culture, and discusses the main theories on SED and how these phenomena compare with unusual experiences in other contexts. The review concludes that the vast majority of these experiences are benign and that they should be considered in light of their biographical, relational, and sociocultural contexts

Development of Autoantibodies Following BNT162b2 mRNA COVID-19 Vaccination and Their Association with Disease Flares in Adult Patients with Autoimmune Inflammatory Rheumatic Diseases (AIIRD) and the General Population: Results of 1-Year Prospective Follow-Up Study

Development of autoantibodies following BNT162b2 mRNA COVID-19 vaccination and their association with disease flares in adult patients with autoimmune inflammatory rheumatic diseases (AIIRD) and the general population: results of 1-year prospective follow-up study. We conducted a prospective study aimed at investigating the incidence of appearance of autoantibodies (antinuclear, antiphospholipid, and rheumatoid factor) in the sera of 463 adult patients with AIIRD compared to 55 controls from the general population prior to, and following the second and third vaccine doses, and at 1-year of follow-up. Pre- and post-vaccination disease activity indices and the association of autoantibodies with rheumatic disease flares and new onset AIIRD were examined. Autoantibody development of any type in AIIRD patients vs. the controls was 4.0% (vs. 6.7%, p = 0.423) following two vaccine doses and 7.6% (vs. 0%, p = 0.152) after three doses. There was no significant difference in sex, age, or disease-type among individuals with and without autoantibody development, regardless of the immunosuppressant use. More patients developed autoantibodies following the third than the second vaccine dose (p = 0.004). Disease flares occurred in 5.8% and 7.2% of AIIRD patients following second and third vaccine doses, respectively, with autoantibody production increasing the risk of flares following the second (p = 0.002) and third (p = 0.004) vaccine doses. BNT162b2 vaccination resulted in the development of autoantibodies in a minority of AIIRD patients and controls. Autoantibody development was associated with disease flares in patients, but no new-onset autoimmunity was observed

Gender-specific abnormalities in the serotonin transporter system in panic disorder

The central serotonergic system has been implicated in the pathophysiology of panic disorder (PD) by evidence of abnormally elevated serotonin-turnover, reduced pre- and post-synaptic 5-HT(1A-)receptor sensitivity and binding and clinical improvement during administration of agents that enhance serotonergic transmission. Polymorphisms in genes that putatively influence serotonergic neurotransmission increase the vulnerability for developing PD specifically in males. We tested the hypotheses that serotonin transporter (5-HTT) binding is elevated in PD subjects vs. healthy controls in regions where in vivo evidence exists for both elevated 5-HTT and 5-HT1A receptor levels in PD and investigated whether the extent of this difference depends upon gender. Volunteers were out-patients with current PD (n=24) and healthy controls (n=24). The non-displaceable component of 5-HTT binding-potential (BPND) was measured using positron emission tomography and the 5-HTT selective radioligand, [C-11]DASB. PD severity was assessed using the PD Severity Scale. The 5-HTT-BPND was increased in males with PD relative to male controls in the anterior cingulate cortex (F=8.96, p(FDR)=0.01) and midbrain (F=5.09, p(FDR)=0.03). In contrast, BPND did not differ between females with PD and female controls in any region examined. The finding that 5-HTT-binding is elevated in males but not in females with PD converges with other evidence suggesting that dysfunction within the central serotonergic system exists in PD, and also indicates that such abnormalities are influenced by gender. These findings conceivably may reflect a sexual dimorphism that underlies the greater efficacy of serotonin reuptake inhibitor treatment in females vs. males with PD