Contraction Waves Research Articles

The Male Reproductive System of the Kissing Bug, Rhodnius prolixus Stål, 1859 (Hemiptera: Reduviidae: Triatominae): Arrangements of the Muscles and the Myoactivity of the Selected Neuropeptides

The gross anatomy of the male reproductive structures and their associated musculature are described in the blood-gorging vector of Chagas disease, Rhodnius prolixus. The male reproductive system is composed of muscular tissues each performing contractions that aid in the movement of sperm out of the testis into the vas deferens, seminal vesicle and then into the ejaculatory duct, along with proteins and lipids from the transparent and opaque accessory glands. Phalloidin staining shows the various patterns of muscle fiber layers, from thin circular to more complex crisscross patterns, implying subtle differences in the form of the contractions and movement of each of the structures, allowing for waves of contractions or twisting patterns. The transcripts for the receptors for proctolin, myosuppressin (RhoprMS) and for the extended FMRFamides are expressed in the various regions of the reproductive system, and the nerve processes extending over the reproductive structures are positive for FMRFamide-like immunoreactivity, as are neurosecretory cells lying on the nerves. Proctolin and AKDNFIRFamide are strong stimulators for the frequency of the contractions, and RhoprMS can inhibit the proctolin-induced contractions. Taken together, this work implicates these two families of peptides in coordinating the male reproductive structures for the successful transfer of sperm and the associated accessory gland fluid to the female during copulation.

Correlation between nonalcoholic fatty liver disease and left ventricular diastolic dysfunction in non-obese adults: a cross-sectional study

Background and aimsNon-alcoholic fatty liver disease (NAFLD) is associated with a greater risk of developing cardiovascular disease and have adverse impacts on the cardiac structure and function. Little is known about the effect of non-obese NAFLD upon cardiac function. We aimed to compare the echocardiographic parameters of left ventricle (LV) between non-obese NAFLD group and control group, and explore the correlation of non-obese NAFLD with LV diastolic dysfunction.Methods and resultsIn this cross-sectional study, 316 non-obese inpatients were enrolled, including 72 participants with NAFLD (non-obese NAFLD group) and 244 participants without NAFLD (control group). LV structural and functional indices of two groups were comparatively analyzed. LV diastolic disfunction was diagnosed and graded using the ratio of the peak velocity of the early filling (E) wave to the atrial contraction (A) wave and E value. Compared with control group, the non-obese NAFLD group had the lower E/A〔(0.80 ± 0.22) vs (0.88 ± 0.35), t = 2.528, p = 0.012〕and the smaller LV end-diastolic diameter〔(4.51 ± 0.42)cm vs (4.64 ± 0.43)cm, t = 2.182, p = 0.030〕. And the non-obese NAFLD group had a higher prevalence of E/A < 1 than control group (83.3% vs 68.9%, X2 = 5.802, p = 0.016) while two groups had similar proportions of LV diastolic dysfunction (58.3% vs 53.7%, X2 = 0.484, p = 0.487). Multivariate logistic regression analysis showed that non-obese NAFLD was associated with an increase in E/A < 1 (OR = 6.562, 95%CI 2.014, 21.373, p = 0.002).ConclusionsNon-obese NAFLD was associated with decrease of E/A, while more research will be necessary to evaluate risk of non-obese NAFLD for LV diastolic dysfunction in future.

Esophageal motility disorders in symptomatic patients and its relation to age

BackgroundAlthough swallowing disorders can impact individuals of any age, some are unique to the elderly, and others are frequent. Some disorders, such as achalasia, are diagnosed by esophageal manometry studies, which assess lower esophageal sphincter (LES) pressure and relaxation, peristalsis in the esophageal body, and contraction wave characteristics. This research aimed to evaluate esophageal motility dysfunction in symptomatic patients and its relation to age.MethodsConventional esophageal manometry was performed on 385 symptomatic patients who were divided into two groups; Group A (age < 65 years old) and Group B (age ≥ 65 years). The geriatric assessment for Group B included cognitive, functional, and clinical frailty scales (CFS). Additionally, a nutritional assessment was done for all patients.ResultsAbout one-third of the patients (33%) had achalasia, in which manometric results were significantly higher in Group B (43.4%) than in Group A (28.7%) (P = 0.016).The resting lower esophageal sphincter (LES) pressure, as determined by manometry examination, was significantly lower in Group A than in Group B. In contrast, complete LES relaxation percentage and normal esophageal body peristalsis were significantly higher in Group A than in Group B. Patients who exhibited evidence of achalasia in the manometric study had a significantly increased risk of established malnutrition and functional impairment.ConclusionsAchalasia is a prevalent cause of dysphagia in elderly patients, placing them at risk of malnutrition and functional impairment. Thus, a multidisciplinary approach is vital when providing care for this population.

Effect of valve spacing on peristaltic pumping

Peristaltic fluid pumping due to a periodically propagating contraction wave in a vessel fitted with one-way elastic valves is investigated numerically. It is concluded that the valve spacing within the vessel relative to the contraction wavelength plays a critical role in providing efficient pumping. When the valve spacing does not match the wavelength, the valves open asynchronously and the volume of the vessel segments bounded by two consecutive valves changes periodically, thereby inducing volumetric fluid pumping. The volumetric pumping leads to higher pumping flowrate and efficiency against an adverse pressure gradient. The optimum pumping occurs when the ratio of valve spacing to contraction wavelength is about . This pumping regime is characterized by a longer period during which the valves are open. The results are useful for further understanding the pumping features of lymphatic system and provide insight into the design of biomimetic pumping devices.

PREMATURE VENTRICULAR CONTRACTIONS AS AN ADDITIONAL RISK FACTOR FOR THE ARTERIAL THROMBOEMBOLISM

Premature ventricular contractions (PVCs) are not included in the risk factors for arterial thromboembolism. Aim: To determine the relationship between PVCs and the development of arterial thromboembolic complications. Methods: The study included 440 patients with PVCs 700 or more per 24 hours, control group - 88 people with PVCs less than 700. All patients underwent laboratory and instrumental studies: lipid spectrum, hemostasis indicators; 24-hours ECG monitoring; echocardiography (EchoCG); Doppler ultrasound and digital sphygmography (SG) of the main arteries; ultrasound of the aorta branches, renal arteries. According to the indications - stress EchoCG with physical exercises, coronary angiography, pancerebral angiography, renal arteries angiography, computed tomography, magnetic resonance imaging of the brain. All patients of the main group were divided into 2 subgroups, depending on the moment of occurrence of PVCs ventricular systole in the cardiac cycle, regardless of the ectopic center: subgroup A (120) - patients with PVCs before the peak of transmitral blood flow; subgroup B (320) - after the peak of the transmitral blood flow. Patients were observed during 1 year and the development of arterial thromboembolic events was analyzed. Results: According to the main clinical, laboratory and instrumental data, patients of subgroups A, B and the control group were equivalent. Also, during 1 year, a statistically significantly higher development of arterial thromboembolic events was observed in subgroup A. When comparing linear blood flow velocity and volumetric blood flow, there was a significant increase in parameters during the spreading of the first post-extrasystolic contraction wave. A similar trend was observed in the parameters of the kinetics of the arterial vascular wall (velocity, acceleration, power, work). Conclusion: PVCs are an additional risk factor for arterial thromboembolic events. The main danger is not the PVC itself, but the wave of the first post-extrasystolic contraction, which can become the starting point for the instability of atherosclerotic plaques, leading to tears, parietal thrombosis, and embolism in the arterial vessels.

Effects of PAR2 Gene Knockout on Visceral Sensitivity, Stress Behaviors, and Colonic Electrical Activities in Irritable Bowel Syndrome.

Irritable bowel syndrome (IBS) could seriously affect the patient's health quality by its recurrence. There is a great medical and social need to explore the mechanisms and new treatment strategies of IBS. To explore the influence of protease-activated receptor 2 (PAR2) gene knockout on IBS visceral sensitivity, stress behaviors, and colonic electrical activities. The PAR2 gene knockout and IBS model rats were generated and divided into PAR2+/+ wild control (WC) group, PAR2+/+ wild IBS model (WM) group, PAR2-/- knockout control (KC) group and PAR2-/- knockout IBS model (KM) group. The stress behaviors scores, minimum rectal fluid injection capacity threshold value of abdominal withdrawal reflex (AWR) = 3, and the colonic electrical activities indexes were recorded and the experimental results were analyzed statistically. (1) PAR2 gene deletion and IBS models were successfully generated. (2) The scores of aggressive and exploratory behaviors in WM and KM groups were higher than WC and KC groups (p < 0.05). The grooming behavior scores in WC and KC groups were higher than the WM and KM groups (p < 0.05). WM group had the highest aggressive and exploratory behavior scores; WC group had the highest grooming behavior scores. (3) The minimum rectal fluid injection capacity threshold value of AWR = 3 in WM and KM groups were lower than WC and KC groups (p < 0.05); WM group had the lowest value. (4) The maximum amplitude and wave frequency of colonic fast and slow waves in WM and WC groups were greater than in the KM and KC groups, respectively (p < 0.05). The amplitude index and number of colonic contraction waves in WM and KM groups were greater than the WC and KC groups (p < 0.05). Colonic electrical activity indexes were highest in the WM group. The PAR2 gene deletion could have a beneficial effect on visceral sensitivity, stress behaviors and colonic electrical activities in rats with IBS.

Effects of peristaltic amplitude and frequency on gastric emptying and mixing: a simulation study.

The amplitude and frequency of peristaltic contractions are two major parameters for assessing gastric motility. However, it is not fully understood how these parameters affect the important functions of the stomach, such as gastric mixing and emptying. This study aimed to quantify the effects of peristaltic amplitude and frequency on gastric mixing and emptying using computational fluid dynamics simulation of gastric flow with an anatomically realistic model of the stomach. Our results suggest that both the increase and decrease in peristaltic amplitude have a significant impact on mixing strength and emptying rate. For example, when the peristaltic amplitude was 1.2 times higher than normal, the emptying rate was 2.7 times faster, whereas when the amplitude was half, the emptying rate was 4.2 times slower. Moreover, the emptying rate increased more than proportionally with the peristaltic frequency. The nearest contraction wave to the pylorus and the subsequent waves promoted gastric emptying. These results suggest the importance of maintaining parameters within normal ranges to achieve healthy gastric function.

SoRSS: A Soft Robot for Bio-Mimicking Stomach Anatomy and Motility.

A human stomach is an organ in the digestive system that breaks down foods by physiological digestion, including mechanical and chemical functions. The mechanical function is controlled by peristaltic waves generated over the stomach body, known as antral contraction waves (ACW). The stomach's physiological digestion is essential to sustain nutrition and health in humans. Replicating the digestion process in a robot provides a test environment as an alternative solution to in vivo testing, which is difficult in practice. Stomach robots made of rigid rods and metal cylinders are unrealistic replicas to contract and expand like biological examples. With soft robotics technology, it is possible to translate biological behavior into an engineering context. Soft robotics introduce potential methods to replicate peristaltic waves and achieve a soft-bodied stomach simulator. This work presents a soft robotic stomach simulator's (SoRSS) concept, design, and experimental validation. A pneumatic bellows actuation for linear elongation and a ring of bellows actuation for circular contraction are proposed first. Multi-ring actuators are then arranged to form an SoRSS that generates ACW and antral contracting pressure (ACP). The SoRSS satisfies the specification of human stomach anatomy and motility and finally undergoes experimental validation using videofluoroscopy with the outcomes presenting the ACW, ACP, and the digestion phases during the actuation process. Those are compared with other medical studies to validate SoRSS functionality.

Peristaltic transport of a power-law fluid induced by a single wave: A numerical analysis using the cumulant lattice Boltzmann method

Peristaltic pumping is the primary mechanism of food transport in the human intestine. Intestinal contents are often modeled as power-law fluids with low-behavior indices (n &amp;lt; 1). Peristaltic flows were studied for periodic contraction waves (L/λ=1) with infinitely long wavelengths (λ/D→∞) in the Stokes flow regime (Re→0). However, the peristaltic flow generated by an isolated contraction wave with a short wavelength at nonzero Reynolds numbers is more relevant to physiological conditions. In this study, we investigated the peristaltic transport of a power-law fluid with a low behavior index of n = 0.21 at nonzero Reynolds numbers up to Re = 10, generated by a single short contraction wave. First, we investigated the analytical solution for the peristaltic transport of the power-law fluid for λ/D→∞ and Re→0. The analytical solution shows that the discharge flow rate of a power-law fluid generated by a single contraction wave is much smaller than that of a Newtonian fluid (n = 1). Next, we investigated the peristaltic transport for Re≤ 10 using the cumulant lattice Boltzmann method. The numerical results demonstrate that the discharge flow rate for the power-law fluid sharply increased owing to the inertia effect. The power-law fluid induces an asymmetric flow field with respect to the contraction wave at smaller Reynolds numbers than Newtonian fluids. The inertia effect was increased by the sharpness of the contraction wave. These results suggest that intestinal contents can be transported more quickly by an isolated contraction wave with a shorter wavelength when the contents have low consistency indices or when the contraction wave has a large propagation velocity.

Cryptogenic stroke and extrasystolic arrythmia: is there any correlation?

Abstract Up to 45% of all ischemic strokes (IS) are cryptogenic. Purpose To reveal the possible reasons of cryptogenic IS. Methods We analyzed the cases of computer tomography verified IS in patients admitted the hospital during the period of 3 years. All these 268 patients had unidentified source of IS. We analyzed hemostasiograms, lipids levels, performed echocardiography, Doppler ultrasound of brachiocephalic arteries, 24-hours ECG monitoring and common carotid arteries sphygmography (SG). Results None of the patients had atrial fibrillation, hemodynamically significant stenoses of brachiocephalic arteries or hematological pathology associated with hypercoagulation. 234 (87.3%) patients had atherosclerotic plaques in carotid area bifurcation (in 36 (13.4%) – intima-media thickness was 1.1 mm, in 74 (27.6%)– stenosis &amp;lt;40%, in 124 (46.3%) had 40–69% stenosis in diameter). The internal carotid stenosis in diameter is calculated by ECST, NASCET and St. Mary's ratio criteria. To detect the type of the plaques we used Gray-Weale–Nicolaides ultrasound classification. In 39 (14.5%) was type I: uniformly echolucent plaque; in 88 (32.8%) type II: predominately echolucent plaque; in 71 (26.5%) type III: predominantly echogenic plaque, none had type IV: uniformly echogenic plaque or type V: heavy calcification. In 24-hours ECG monitoring and SG we revealed that most of the patients – 244 (91.0%) had extrasystolic arrhythmia which ventricular contraction of extrasystole appeared in the early phase of cardiocycle – before the transmitral blood flow peak. In 1st post-extrasystolic wave after such extrasystole we detected the growth of linear blood flow speed in carotid bifurcation (2.5 m/sec) and kinetic arteries parameters of SG (2.6 times). Conclusion The appearance of IS is higher in patients with extrasystolic arrhythmia appearing in the cardiocycle before the transmitral blood flow peak. In cryptogenic stroke, the reason of it can be the atherosclerotic plaque defragmentation with further embolism, caused by the additional mechanical trauma of increased hemodynamical and kinetic parameters of pulse wave of the 1st post-extrasystolic contraction. Funding Acknowledgement Type of funding sources: None.

Extrasystoles: relationship with arterial thromboembolic complications

Aim to determine the relationship between extrasystoles (ES) and the development of arterial thromboembolic complications.&#x0D; Material and methods. The study included 440 patients with ES 700 or more per 24 hours, control group 88 people with ES less than 700. All patients underwent laboratory and instrumental examinations: lipid spectrum, hemostasis indicators; 24-hours ECG monitoring; echocardiography (EchoCG); Doppler ultrasound and digital sphygmography (SG) of the main arteries; ultrasound of the aorta branches, renal arteries. According to the indications, the patients were administered: stress EchoCG with physical exercises, coronary angiography, pancerebral angiography, renal arteries angiography, computed tomography, magnetic resonance imaging of the brain. All patients of the main group were divided into 2 subgroups, depending on the moment of occurrence of ES ventricular systole in the cardiocycle, regardless of the ectopic center: subgroup A (120) patients with ES before the peak of transmitral blood flow; subgroup B (320) after the peak of the transmitral blood flow. Patients were observed during 1 year and the development of arterial thromboembolic events was analyzed.&#x0D; Results. According to the main clinical, laboratory and instrumental data, patients of subgroups A, B and the control group were equivalent. Also, during 1 year follow-up, a significantly higher development of arterial thromboembolic events was observed in subgroup A. When comparing the linear blood flow velocity and volumetric blood flow, there was a significant increase in parameters during the spreading of the first post-extrasystolic contraction wave. A similar trend was observed in the parameters of the kinetics of the arterial vascular wall (velocity, acceleration, power, work).&#x0D; Conclusion. Extrasystoles are an additional risk factor for arterial thromboembolic events. The main danger is not the ES itself, but the wave of the first post-extrasystolic contraction, which can become the starting point for the instability of atherosclerotic plaques, leading to tears, parietal thrombosis, and embolism along the arterial vessel.

Effect of electroacupuncture on colonic motility and RhoA and ROCK protein expression in IBS-D rats

To observe the effect of electroacupuncture (EA) of "Tianshu"(ST25) and "Shangjuxu"(ST37)on gastrointestinal motility, psychological abnormality and expression of RhoA and ROCK protein in rats with diarrhea predominant irritable bowel syndrome (IBS-D), so as to explore its underlying mechanism in improving IBS-D. Thirty-six male rats were randomly and equally divided into control, model, EA and medication groups (n=9 in each group). The IBS-D model with psychological abnormality was established by gavage of dinitrobenzene sulfonic acid (DNBS) + chronic restraint stress. EA (2 Hz/100 Hz, 0.3 mA) was applied to bilateral ST25 and ST37 for 20 min, once a day for 7 days. Rats of the medication group received gavage of pinaverium bromide solution (15 mg/kg), once a day for 7 days. The rats' food intake in 24 h, body mass and colonic contraction waves were recorded. The anhedonia-related behavior was measured using the sucrose consumption test. The elevated plus maze test (the open-arm residence time ratio) was used to assess the anxiety-like behavior. The small intestinal propulsion rate test was used to assess the intestinal motility. The expression levels of RhoA and ROCK proteins in the colonic tissue were measured by Western blot. After modeling, the body mass, food consumption, sucrose preference index, the open-arm residence time ratio andlatency of colonic contraction waves were significantly decreased (P<0.05), and the number of contraction waves, intestinal propulsive rate, and the expression levels of RhoA and ROCK proteins considerably increased (P<0.01，P<0.05) in the model group relevant to the control group. Following the interventions, the decrease of body mass, food consumption, sucrose preference index, open-arm residence time ratio and latency of contraction waves, and the increase of the contraction waves, intestinal propulsive rate, and the expression levels of RhoA and ROCK proteins were all reversed by both EA and medication (P<0.05，P<0.01). The effect of EA was significantly superior to that of medication in increasing the sucrose pre-ference index (P<0.05). EA can improve both colonic motility and psychological disorders in IBS-D rats with psychological disorder, which may be related to its function in down-regulating the expression of colonic RhoA and ROCK proteins.

Distension contraction plots of pharyngeal/esophageal peristalsis: next frontier in the assessment of esophageal motor function.

Esophageal peristalsis consists of initial inhibition (relaxation) followed by excitation (contraction), both of which move sequentially in the aboral direction. Initial inhibition results in receptive relaxation and bolus-induced luminal distension, which allows propulsion by the contraction with minimal resistance to flow. Similar to the contraction wave, luminal distension has unique waveform characteristics in normal subjects; both are modulated by bolus volume, bolus viscosity, and posture, suggesting a possible cause-and-effect relationship between the two. Distension contraction plots in patients with dysphagia with normal bolus clearance [high-amplitude esophageal contractions (HAECs), esophagogastric junction outflow obstruction (EGJOO), and functional dysphagia (FD)] reveal two major findings: 1) unlike normal subjects, there is luminal occlusion distal to bolus during peristalsis in certain patients, i.e., with type 3 achalasia and nonobstructive dysphagia; and 2) bolus travels through a narrow lumen esophagus during peristalsis in patients with HAECs, EGJOO, and FD. Aforementioned findings indicate a relative dynamic obstruction to the bolus flow during peristalsis and reduced distensibility of esophageal wall in the bolus segment of the esophagus. We speculate that a normal or supernormal contraction wave pushing bolus against resistance is the mechanism of dysphagia sensation in significant number of patients. Representations of distension and contraction, combined with objective measures of flow timing and distensibility are complementary to the current scheme of classifying esophageal motility disorders based solely on the characteristics of contraction phase of peristalsis. Better understanding of the distensibility of the bolus-containing segment of the esophagus during peristalsis will lead to the development of novel medical and surgical therapies in the treatment of dysphagia in significant number of patients.

EndoFLIP Topography: Motor Patterns in an Obstructed Esophagus

EndoFLIP Topography: Motor Patterns in an Obstructed Esophagus

Extrasystolic arrhythmia: is it an additional risk factor of cryptogenic stroke?

Aim to study the development of ischemic stroke (IS) or transient ischemic attack (TIA) in patients with extrasystoles (ES), depending on the moment of ES ventricular systole occurrence in cardiocycle.&#x0D; Material and methods. The study group included 440 patients with ES 700 per day; the control group consisted of 88 patients with ES 700 per day. The following instrumental and laboratory methods were used: echocardiography, Doppler ultrasound of brachiocephalic arteries, 24-hours ECG monitoring, digital sphygmography of common carotid arteries; CT or MRI of the brain; lipid spectrum. The study group was divided into two subgroups according to the moment of ES ventricular systole occurrence in cardiocycle, regardless of ectopia: subgroup 1 120 patients with ES before the transmitral blood flow peak; subgroup 2 320 patients with ES after the transmitral blood flow peak. We analyzed the development of stroke or TIA during 1 year.&#x0D; Results. For most parameters, subgroups 1, 2 and the control group were identical. The important differences were registered in the hemodynamic and kinetic parameters of common carotid arteries. The earlier the ES ventricular systole occurred in cardiocycle, the higher increase of the parameters was observed. During one year of follow-up, stroke and TIA occurred more frequently in subgroup 1.&#x0D; Conclusion. ES is an additional risk factor for stroke. The most dangerous is ES with ventricular systole occurrence before transmitral blood flow peak. The wave of the 1st post-extrasystolic contraction causes additional trauma of arterial wall and can become a key factor for instability of atherosclerotic plaques with their defragmentation, embolism and stroke.

Effect of different acupuncture and moxibustion methods on uterine contraction and microcirculation in cold congealing dysmenorrhea rats

To observe and compare the effects of different acupuncture and moxibustionmethods at "San-yinjiao" (SP6) on uterine contraction and microcirculation in cold congealing dysmenorrhea rats, so as to explore its mechanism underlying treatment of dysmenorrhea. A total of 140 female SD rats were randomly divided into normal control, mo-del, perpendicular needling, transverse needling and moxibustion groups, with 28 rats in each group. The cold congealing dysme-norrhea rat model was prepared by exposure in a freezer (25 ℃) for 4 h, once daily for 5 days, and subcutaneous injection of estradiol benzoate (once daily for 10 days) and intra-abdominal injection of oxytocin (once). For rats in three intervention groups, acupuncture needles were inserted into bilateral SP6 perpendicularly or transversely to a depth of 4~5 mm and retained for 20 min, or moxibustion was applied to SP6 for 20 min. The uterine contraction degree and the uterine microcirculation were recorded. The expression levels of transient receptor potential vanilloid 1 (TRPV1) and heat shock protein 70 (HSP70) in local tissues of SP6 area were detected by immunohistochemistry. The expression levels of μopioid receptor and endothelin 1 (ET1) mRNA in the uterus were assessed by quantitative real time-PCR. After modeling and compared with the normal control group, the number and peak-to-peak values of uterine contraction waves, and uterine motility were significantly increased (P<0.01,P<0.05), while the speed of blood flow in the microvessels was slowed down (P<0.01), diameters of the uterine microvessels and capillaries (cap) shrank obviously (P<0.01) in the model group. After the intervention, all indexes of uterine contraction and microcirculation were improved in three intervention groups (P<0.01, P<0.05), while transverse needling and moxibustion showed better effects compared to perpendicular needling (P<0.05, P<0.01). The expression of TRPV1 and HSP70 in SP 6 area had no significant changes (P>0.05), while the uterine μopioid receptor mRNA expression decreased (P<0.01), and ET1 mRNA expression increased (P<0.01) in the model group relevant to the normal control group. Following the intervention, the expression levels of TRPV1 and HSP70 in SP6 area were increased (P<0.05, P<0.01), and expression levels of uterine μopioid receptor mRNA increased (P<0.05, P<0.01) and uterine ET1 mRNA decreased (P<0.05, P<0.01) in the three intervention groups. The effect of moxibustion was considerably better than those of two acupuncture groups in up-regulating TRPV1 expression (P<0.05). Both transverse needling and moxibustion showed better effects of down-regulating uterine ET1 mRNA expression than perpendicular needling (P<0.01). Transverse needling and moxibustion at SP6 have a better effect of relieving ute-rine contraction and improving uterine microcirculation than perpendicular needling, which may be related to their effects in up-re-gulating the expression of TRPV1 and HSP70 in SP6 area, thereby modulating the mRNA expression of μ opioid receptor and ET1 in uterine tissue.

Cortical softening elicits zygotic contractility during mouse preimplantation development.

Actomyosin contractility is a major engine of preimplantation morphogenesis, which starts at the 8-cell stage during mouse embryonic development. Contractility becomes first visible with the appearance of periodic cortical waves of contraction (PeCoWaCo), which travel around blastomeres in an oscillatory fashion. How contractility of the mouse embryo becomes active remains unknown. We have taken advantage of PeCoWaCo to study the awakening of contractility during preimplantation development. We find that PeCoWaCo become detectable in most embryos only after the second cleavage and gradually increase their oscillation frequency with each successive cleavage. To test the influence of cell size reduction during cleavage divisions, we use cell fusion and fragmentation to manipulate cell size across a 20- to 60-μm range. We find that the stepwise reduction in cell size caused by cleavage divisions does not explain the presence of PeCoWaCo or their accelerating rhythm. Instead, we discover that blastomeres gradually decrease their surface tensions until the 8-cell stage and that artificially softening cells enhances PeCoWaCo prematurely. We further identify the programmed down-regulation of the formin Fmnl3 as a required event to soften the cortex and expose PeCoWaCo. Therefore, during cleavage stages, cortical softening, mediated by Fmnl3 down-regulation, awakens zygotic contractility before preimplantation morphogenesis.

An 𝐿^{𝑝} shock admissibility condition for conservation laws

We estimate the L p L^p ( p &gt; 0 p&gt;0 ) local distance between piecewise constant solutions to the Cauchy problem of conservation laws and propose a shock admissibility condition for having an L p L^p local contraction of such solutions. Moreover, as an application, we prove that there exist L p L^p locally contractive solutions on some set of initial functions, to the Cauchy problem of conservation laws with convex or concave flux functions. As a result, for conservation laws with convex or concave flux functions, we see that rarefaction waves have an L q L^q ( q ≥ 1 q\geq 1 ) local contraction and shock waves have an L r L^r ( 0 &gt; r ≤ 1 0&gt;r\leq 1 ) local contraction.

Leadless pacemaker technology: clinical evidence of new paradigm of pacing.

Despite continuous technological developments, transvenous pacemakers (PM) are still associated with significant immediate and long-term complications, mostly lead or pocket-related. Recent technological advances brought to the introduction in clinical practice of leadless PM for selected cohort of patients. These miniaturize devices are implanted through the femoral vein and advanced to the right ventricle, without leaving leads in place. Lack of upper extremity vascular access and/or high infective risk in patients requiring VVI pacing are the most common indications to leadless PM. The recently introduced MICRA AV leadless PM also allows ventricular synchronization through mechanical sensing of atrial contraction waves, thus solving the problem of AV synchronization. This review will discuss and summarize available clinical evidence on leadless PM, their performance compared to transvenous devices, current applications and future perspectives.

Computational Modeling of Drug Dissolution in the Human Stomach.

A computational model of drug dissolution in the human stomach is developed to investigate the interaction between gastric flow and orally administrated drug in the form of a solid tablet. The stomach model is derived from the anatomical imaging data and the motion and dissolution of the drug in the stomach are modeled via fluid-structure interaction combined with mass transport simulations. The effects of gastric motility and the associated fluid dynamics on the dissolution characteristics are investigated. Two different pill densities are considered to study the effects of the gastric flow as well as the gravitational force on the motion of the pill. The average mass transfer coefficient and the spatial distributions of the dissolved drug concentration are analyzed in detail. The results show that the retropulsive jet and recirculating flow in the antrum generated by the antral contraction wave play an important role in the motion of the pill as well as the transport and mixing of the dissolved drug concentration. It is also found that the gastric flow can increase the dissolution mass flux, especially when there is substantial relative motion between the gastric flow and the pill.