The Effect of Dehydration and High-Volume Resistance Exercise on Intracellular and Local Muscular Fluid Shifts - A Pilot Study

Hypertonic hypovolemia (dehydration) could disrupt the balance between extracellular water (ECW) and intracellular water (ICW). Notably, high-volume resistance exercise (RE) accumulates metabolites resulting in acute muscle swelling (increased ICF). However, the impact of hypertonic hypovolemia state on ECW and ICW distribution after RE is not known. PURPOSE: To determine the effect of acute dehydration on fluid balance after RE. METHODS: 7 resistance-trained males completed two identical high-volume RE, separated by two weeks (bilateral leg press and knee extensions exercises [5 sets of 10 repetitions at 80% of 1 repetition maximum]) either in a euhydrated (EH; urine specific gravity [USG] \u3c 1.020) or dehydrated state (DH; USG ≥ 1.020; 24hr fluid fast). Total body water (TBW) and the ratio of ICW to ECW (ICW/ECW) were measured using bioelectrical impedance spectroscopy before (PRE), 1h, and 3h after RE. The rectus femoris thickness (RFT) was imaged using ultrasound at PRE, immediately (IP), 10m, 15m, and 30m after RE. Vastus lateralis samples were collected at PRE, 1h, and 3h and were immediately weighed (Wt) before and after heating at 80°C for 55 minutes. Repeated measures ANOVAs were used to identify the differences, and effect sizes were calculated if p values were trending. RESULTS: A significant (p \u3c 0.05) condition effect was observed for TBW, while a time effect was observed for ICW/ECW and RFT. For TBW, EH (1.00±0.06L) was greater than DH (0.95±0.05L). For ICW/ECW, PRE (1.00±0.00L) was lower than 1h (1.05±0.10L) and 3h (1.03±0.05L), while 1h was greater than PRE and 3h. For RFT, PRE (17.1±0.9mm) was less thick than IP (23.7±0.9mm), 10m (22.3±1.0mm), 15m (22.0±0.9mm), and 30m (21.5±1.0mm) while IP was thicker than all time points. Furthermore, EH (22.8±1.4mm) trended to have thicker RFT than DH (19.9±0.8mm; p=0.082; Cohen’s f = 0.85; large effect size). Additionally, a significant condition x time effect was observed for Wt. For Wt, EH (1.07±0.04mg) had a greater change in muscle weight than DH (1.01±0.06mg) at 1h. CONCLUSION: These results suggest that high volume RE can cause fluid shift from the extracellular to the intracellular compartment (i.e., increase ICW/ECF and RFT) regardless of the hydration status. Intriguingly, at the intramuscular level, it appears that the intramuscular water content after RE is less in dehydrated than euhydrated state (i.e., less changes in Wt)

The outer-membrane export signal of Porphyromonas gingivalis type IX secretion system (T9SS) is a conserved C-terminal \beta-sandwich domain

In the recently characterized Type IX Secretion System (T9SS), the conserved C-terminal domain (CTD) in secreted proteins functions as an outer membrane translocation signal for export of virulence factors to the cell surface in the Gram-negative Bacteroidetes phylum. In the periodontal pathogen Porphyromonas gingivalis, the CTD is cleaved off by PorU sortase in a sequence-independent manner, and anionic lipopolysaccharide (A-LPS) is attached to many translocated proteins, thus anchoring them to the bacterial surface. Here, we solved the atomic structure of the CTD of gingipain B (RgpB) from P. gingivalis, alone and together with a preceding immunoglobulin-superfamily domain (IgSF). The CTD was found to possess a typical Ig-like fold encompassing seven antiparallel β-strands organized in two β-sheets, packed into a β-sandwich structure that can spontaneously dimerise through C-terminal strand swapping. Small angle X-ray scattering (SAXS) revealed no fixed orientation of the CTD with respect to the IgSF. By introducing insertion or substitution of residues within the inter-domain linker in the native protein, we were able to show that despite the region being unstructured, it nevertheless is resistant to general proteolysis. These data suggest structural motifs located in the two adjacent Ig-like domains dictate the processing of CTDs by the T9SS secretion pathway

The Effect of Hydration Status on Sleep Quality: A Pilot Study

Sleep improves muscle recovery and cognitive health and can be impaired by physiological and mental stress. Dehydration can induce stress which leads to sleep impairment and thus could affect the readiness for and recovery from exercise. However, no study has examined the effect of hydration on sleep before and after resistance exercise (RE). PURPOSE: To examine the effect of hydration status on sleep before and after RE. METHODS: 7 resistance-trained men completed two identical RE consisting of bilateral leg press and knee extensions (5 sets of 10 repetitions at 80% of 1 repetition maximum) in a euhydrated state (EU; urine specific gravity (USG) \u3c 1.020) and in a dehydrated state (DE: USG ≥ 1.020). The two conditions were separated by 2 weeks in random order. During DE, participants underwent a 24-hr fluid restriction the day before RE and consumed only 1.5 L water following RE throughout the day. Participants wore a wearable sleep device, and sleep efficiency (SE), light sleep (LS), rapid eye movement (REM), and slow wave sleep (SWS) were measured the night before (PRE) and the night after (POST) RE. A 2X2 ANOVA and effect sizes (ES) were used to detect differences. RESULTS: No significant (p \u3e 0.05) condition x time effect was observed for any sleep parameters. At PRE, a small ES was observed for SE (1.1%; η2 = 0.05) where EU was more efficient than DE. Additionally, a medium ES was observed for LS (26.2%; η2 = 0.09) and SWS (8%; η2 = 0.08) where EU spent more time in these phases than DE, while EU spent less time in the REM phase (-16.4%; η2 = 0.07) than DE. At POST, a small ES was observed for SE (1.3%; η2 = 0.05) where EU was more efficient than DE. Additionally, a medium ES was observed for REM (-35.7%; η2 = 0.07) and SWS (-8.4%; η2 = 0.08) where EU spent less time in these phases than DE, while EU spent more time in the LS phase (18.7%; η2 = 0.09) than DE. CONCLUSION: The pilot data suggests hydration status could influence sleep. Proper fluid intake could help with sleep efficiency and increase time spent in LS and SWS, which are beneficial for muscle and tissue recovery. Intriguingly, inadequate fluid intake could increase the time spent in REM, which might be due to the mental and physical stresses from dehydration and RE. Combined, these data suggest that hydration status could affect the readiness for and recovery from physical stress

The Effect of Hydration on Readiness and Recovery Before and After Resistance Exercise- A Pilot Study

Dehydration can disturb sleep which is essential for the readiness and recovery process. However, the role of hydration on readiness and recovery indicated by low resting heart rate (RHR) and high heart rate variability (HRV) before and after resistance exercise (RE) is not known. PURPOSE: The purpose of this study was to examine the effect of hydration status on readiness and recovery before and after RE. METHODS: Seven resistance-trained men (age: 21±1 years; weight: 77.8±11.0 kg; height: 177.4±5.3 cm) performed a series of RE that included bilateral leg press and knee extensions (5 sets of 10 repetitions at 80% of 1 repetition maximum). Participants completed the same RE twice with 2 weeks in between. Participants completed one trial in a euhydrated state (EUH; urine specific gravity (USG) \u3c 1.020) and the other in a dehydrated state (DEH: USG ≥ 1.020). For the DEH trial, participants were restricted from consuming fluids for 24 hours prior to the RE and were only permitted to drink 1.5 L of water post-exercise for the remainder of the day. For the EUH trial, participants were instructed to consume fluid throughout the day before and the day of RE to maintain euhydration. Data was collected from a wearable sleep device that participants wore to determine recovery by assessing RHR and HRV. Repeated measures ANOVAs were used to identify the differences, and effect size (ES), resulting effects identified as either small (0.2-0.49), medium (0.5-0.79), or large (\u3e0.8) effects, was calculated. RESULTS: There were no differences in RHR between EUH and DEH on the night before (EUH, 63±13 bpm; DEH, 61±11 bpm; ES=0.16) and after RE (EUH, 59±14 bpm; DEH, 58±9 bpm; ES=0.12; p=0.806). No significant difference was found in recovery between EUH and DEH on the night before (EUH, 37±30 au; DEH, 39±25 au; ES=0.05) or the night after (EUH, 38±29 au; DEH, 42±22 au; ES=0.42; p=0.821) RE. HRV were not different between EUH and DEH on the night before (EUH, 55±27 ms; DEH, 60±32 ms; ES=0.16) and after (EUH, 67±38 ms; DEH, 71±23 ms; ES=0.12; p=0947). CONCLUSION: This pilot study showed hydration status did not impact readiness and recovery before and after RE. However, this could be because the few participants resulted in a low statistical power. Therefore, further studies with more participants could be conducted to better determine how hydration affects readiness and recovery

Permanent and reliable inactivation of Huntington's disease mutation via customized CRISPR/SaCas9 gene editing

Allele-specific CRISPR/SaCas9 gene editing therapy targeting the mutated HTT exon-1 would decrease the formation of mHTT aggregates reducing the neuronal dysfunction and striatum atrophy

Vegetable seed systems among ethnic minority communities in northern Vietnam

Despite the potential of vegetables for nutrition and income in Northern Vietnam, inadequate access to quality seed is a major constraint affecting production, diversity and diet quality. Both self-saved seed and bought seed are important sources for farmers and are linked to the primary purpose of production, market access, seed production knowledge and skills, and trustworthiness of the source. Vegetable diversity, seasonal availability and seed access varies with ethnic group, location, type of and specific vegetables requiring contextualisation of nutrition-sensitive interventions. There are opportunities for farmer sharing and exchange of seeds, vegetables, and knowledge, for safeguarding diversity, promote dietary quality, and improve farmer income

Onchocerciasis: The Pre-control Association between Prevalence of Palpable Nodules and Skin Microfilariae

*Background*: The prospect of eliminating onchocerciasis from Africa by mass treatment with ivermectin has been rejuvenated following recent successes in foci in Mali, Nigeria and Senegal. Elimination prospects depend strongly on local transmission conditions and therefore on pre-control infection levels. Pre-control infection levels in Africa have been mapped largely by means of nodule palpation of adult males, a relatively crude method for detecting infection. We investigated how informative pre-control nodule prevalence data are for estimating the pre-control prevalence of

Totally laparoscopic versus conventional ileoanal pouch procedure – design of a single-centre, expertise based randomised controlled trial to compare the laparoscopic and conventional surgical approach in patients undergoing primary elective restorative proctocolectomy- LapConPouch-Trial

BACKGROUND: Restorative proctocolectomy is increasingly being performed minimal invasively but a totally laparoscopic technique has not yet been compared to the standard open technique in a randomized study. METHODS/DESIGN: This is a two armed, single centre, expertise based, preoperatively randomized, patient blinded study. It is designed as a two-group parallel superiority study. Power calculation revealed 80 patients per group in order to recruit the 65 patients to be analysed for the primary endpoint. The primary objective is to investigate intra-operative blood loss and the need for blood transfusions. We hypothesise that intra-operative blood loss and the need for peri-operative blood transfusions are significantly higher in the conventional group. Additionally a set of surgical and non-surgical parameters related to the operation will be analysed as secondary objectives. These will include operative time, complications, postoperative pain, lung function, postoperative length of hospital stay, a cosmetic score and pre-and postoperative quality of life. DISCUSSION: The trial will answer the question whether there is indeed an advantage in the laparoscopic group in regard to blood loss and the need for blood transfusions. Moreover, it will generate data on the safety and potential advantages and disadvantages of the minimally invasive approach

Effects of muscarinic receptor stimulation on Ca2+ transient, cAMP production and pacemaker frequency of rabbit sinoatrial node cells

We investigated the contribution of the intracellular calcium (Cai2+) transient to acetylcholine (ACh)-mediated reduction of pacemaker frequency and cAMP content in rabbit sinoatrial nodal (SAN) cells. Action potentials (whole cell perforated patch clamp) and Cai2+ transients (Indo-1 fluorescence) were recorded from single isolated rabbit SAN cells, whereas intracellular cAMP content was measured in SAN cell suspensions using a cAMP assay (LANCE®). Our data show that the Cai2+ transient, like the hyperpolarization-activated “funny current” (If) and the ACh-sensitive potassium current (IK,ACh), is an important determinant of ACh-mediated pacemaker slowing. When If and IK,ACh were both inhibited, by cesium (2 mM) and tertiapin (100 nM), respectively, 1 μM ACh was still able to reduce pacemaker frequency by 72%. In these If and IK,ACh-inhibited SAN cells, good correlations were found between the ACh-mediated change in interbeat interval and the ACh-mediated change in Cai2+ transient decay (r2 = 0.98) and slow diastolic Cai2+ rise (r2 = 0.73). Inhibition of the Cai2+ transient by ryanodine (3 μM) or BAPTA-AM (5 μM) facilitated ACh-mediated pacemaker slowing. Furthermore, ACh depressed the Cai2+ transient and reduced the sarcoplasmic reticulum (SR) Ca2+ content, all in a concentration-dependent fashion. At 1 μM ACh, the spontaneous activity and Cai2+ transient were abolished, but completely recovered when cAMP production was stimulated by forskolin (10 μM) and IK,ACh was inhibited by tertiapin (100 nM). Also, inhibition of the Cai2+ transient by ryanodine (3 μM) or BAPTA-AM (25 μM) exaggerated the ACh-mediated inhibition of cAMP content, indicating that Cai2+ affects cAMP production in SAN cells. In conclusion, muscarinic receptor stimulation inhibits the Cai2+ transient via a cAMP-dependent signaling pathway. Inhibition of the Cai2+ transient contributes to pacemaker slowing and inhibits Cai2+-stimulated cAMP production. Thus, we provide functional evidence for the contribution of the Cai2+ transient to ACh-induced inhibition of pacemaker activity and cAMP content in rabbit SAN cells