Supratentorial pressures: Part II: Intracerebral pulse waves

Intracerebral pulse waves were recorded in cat and monkey while intracranial pressure (ICP) manipulations were performed. The intracerebral pulse waves appeared comparable to cerebrospinal fluid (CSF) pulsations. The wave forms were divided into multiple smaller waves, designated P₁ to P₄. The P₁ component was primarily of arterial origin and was accentuated by increasing ICP unrelated to increased venous pressure, most commonly from a mass lesion. Bilateral carotid occlusion resulted in decreased amplitude of P₇. Venous hypertension from jugular venous or sagittal sinus occlusion, on the other hand, accentuated waves P₂ and P₃ more than P₇. This is consistent with a Starling resistor model of the cerebral venous system in which mass lesions may compress low-pressure veins and accentuate the arterial pressure-dependent P₁ wave, whereas venous hypertension causes increased prominence of the later P₂ and P₃ waves.     

Efficacy and safety of add-on levetiracetam in refractory childhood epilepsy

Purpose: The purpose of the present study was to evaluate the efficacy and safety of levetiracetam (LEV) in refractory epileptic children. Methods: The study group included 61 outpatients (7 generalized, 48 localization-related, 3 undetermined, 3 unclassified) aged between 16 months and 18 years. LEV was given twice daily at a total dose of 10 mg/kg/day. The final mean dose was 50.7 mg/kg/day. The mean number of prior anti-epileptic drugs was 5.2. The entire treatment period was more than 6 months after LEV administration. Results: Fifteen children (24.6%) became seizure-free for 6 months after starting LEV, and 18 (29.5%) had a seizure reduction of more than 50% for the entire 6 months. The response rate was 33/61 (54.1%). Responders included 2/3 of patients (66.7%) with epilepsy with continuous spikes and waves during slow sleep and 13/19 (68.4%) with frontal lobe epilepsy. The effective dosage of LEV in the responders demonstrated a wide range (mean, 46.1 mg/kg/day; range, 19.4–59.1 mg/kg/day), and showed bimodal distribution. Adverse events occurred in only two patients who did not require LEV discontinuation. Conclusion: LEV represents an important addition to the treatments available for refractory epileptic children.     

Transcutaneous Electrical Acustimulation Ameliorates Motion Sickness Induced by Rotary Chair in Healthy Subjects: A Prospective Randomized Crossover Study

ObjectivesMotion sickness (MS) is a common physiological response to real or virtual motion. The purpose of this study was to investigate the effects of transcutaneous electrical acustimulation (TEA) on MS and the underlying mechanisms in healthy subjects.Materials and MethodsA total of 50 healthy participants were recruited and randomly assigned into two groups to complete two separate sessions in a crossover study. A Coriolis rotary chair was used as a model to provoke severe MS. The total tolerable rotation time and Graybiel scoring scale were recorded. Gastric slow waves were detected by electrogastrogram. The autonomic nervous function, including the vagal activity, was evaluated by the analysis of heart rate variability derived from the electrocardiogram recording. The serum levels of arginine vasopressin (AVP) and norepinephrine (NE) were examined.ResultsOf note, 22 participants in TEA and only 11 participants in the sham-TEA session completed the entire five-rotation MS stimuli (p = 0.019). TEA significantly prolonged the total tolerable rotation time of MS stimuli (220.4 ± 11.59 vs 173.6 ± 12.3 seconds, p < 0.001) and lowered MS symptom scores (12.56 ± 2.03 vs 22.06 ± 3.0, p < 0.001). TEA improved the percentage of normal gastric slow waves, compared with sham-TEA (56.0 ± 2.1% vs 51.6 ± 2.0%, p = 0.033). TEA also significantly enhanced vagal activity compared with sham-TEA (0.41 ± 0.02 vs 0.31 ± 0.02, p < 0.001). In addition, the increased serum levels of AVP and NE on MS stimulation were markedly suppressed by TEA treatment, compared with sham-TEA (AVP, 56.791 ± 4.057 vs 79.312 ± 10.036 ng/mL, p = 0.033; NE, 0.388 ± 0.037 vs 0.501 ± 0.055 ng/mL, p = 0.021).ConclusionsNeedleless TEA is a potent therapeutic approach for severe MS, as it increases participants' tolerance and ameliorates MS symptoms, which may be attributed to the integrative effects of TEA on autonomic functions and neuroendocrine balance.     

Effect of radial shock wave therapy for carpal tunnel syndrome: A prospective randomized,double‐blind,placebo‐controlled trial

Three recent studies demonstrated the positive effect of extracorporeal shock wave therapy (ESWT) for treating carpal tunnel syndrome (CTS). However, none have entirely proved the effects of ESWT on CTS because all studies had a small sample size and lacked a placebo‐controlled design. Moreover, radial ESWT (rESWT) has not been used to treat CTS. We conducted a prospective randomized, controlled, double‐blinded study to assess the effect of rESWT for treating CTS. Thirty‐four enrolled patients (40 wrists) were randomized into intervention and control groups (20 wrists in each). Participants in the intervention group underwent three sessions of rESWT with nightly splinting, whereas those in the control group underwent sham rESWT with nightly splinting. The primary outcome was visual analog scale (VAS), whereas the secondary outcomes included the Boston Carpal Tunnel Syndrome Questionnaire (BCTQ), cross‐sectional area (CSA) of the median nerve, sensory nerve conduction velocity of the median nerve, and finger pinch strength. Evaluations were performed before treatment and at 1, 4, 8, and 12 weeks after the third rESWT session. A significantly greater improvement in the VAS, BCTQ scores, and CSA of the median nerve was noted in the intervention group throughout the study as compared to the control group (except for BCTQ severity at week 12 and CSA at weeks 1 and 4) (p < 0.05). This is the first study to assess rESWT in a randomized placebo‐controlled trial and demonstrate that rESWT is a safe and effective method for relieving pain and disability in patients with CTS. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:977–984, 2016.     

The distribution, density and three-dimensional histomorphology of Pacinian corpuscles in the foot of the Asian elephant (Elephas maximus) and their potential role in seismic communication

Both Asian (Elephas maximus) and African (Loxodonta africana) elephants produce low-frequency, high-amplitude rumbles that travel well through the ground as seismic waves, and field studies have shown that elephants may utilize these seismic signals as one form of communication. Unique elephant postures observed in field studies suggest that the elephants use their feet to 'listen' to these seismic signals, but the exact sensory mechanisms used by the elephant have never been characterized. The distribution, morphology and tissue density of Pacinian corpuscles, specialized mechanoreceptors, were studied in a forefoot and hindfoot of Asian elephants. Pacinian corpuscles were located in the dermis and distal digital cushion and were most densely localized to the anterior, posterior, medial and lateral region of each foot, with the highest numbers in the anterior region of the forefoot (52.19%) and the posterior region of the hindfoot (47.09%). Pacinian corpuscles were encapsulated, had a typical lamellar structure and were most often observed in large clusters. Three-dimensional reconstruction through serial sections of the dermis revealed that individual Pacinian corpuscles may be part of a cluster. By studying the distribution and density of these mechanoreceptors, we propose that Pacinian corpuscles are one possible anatomic mechanism used by elephants to detect seismic waves.     

Ocular surface temperature: a 3D FEM prediction using bioheat equation

Computational and mathematical human eye models from previous studies which were constructed in two-dimensions (2D) did not give a precise representation of the actual human eye. This work is an extension from an earlier published work on the 2D model. In this paper, a 3D FEM model of the human eye is simulated for the steady state temperature distribution during normal condition and during electromagnetic (EM) wave radiation. Results show a discrepancy of 0.49% for a normal condition as opposed to 1.9% of a 2D model when compared to experimental results from open literatures. Investigations on the EM wave radiations found an average power absorption density of 15,151 and 22,145 Wm(-3) for the 750 and 1500 MHz radiation, respectively. A peak temperature of 38.18( composite function)C was predicted for the 750 MHz radiation while 41.19( composite function)C was computed for the 1500 MHz radiation. These temperatures are in reasonable agreement with the simulated results computed by another report in the past.     

Effects of prostaglandins E2 and F2α on electromyogram of cat colonin vitro

Prostaglandins cause diarrhea, and their production by the gut increases in diarrheal states. We studied the effects of PGF₂ and PGE₂ on the electromyogram recorded from the cat colonin vitro to determine if these prostaglandins might produce electromyographic changes similar to those seen in diarrheal states. PGF₂ decreased slow wave frequency and uncoupled slow wave propagation in the proximal colon. It increased the frequency of migrating spike bursts. PGE₂ had no effect on slow waves, but increased the frequency of the migrating spike burst. PGF₂ produced electromyographic changes similar to those recorded from the colon of cats with spontaneous diarrhea or after exposure to diarrhea-producing agents such as ricinoleate or quinidine. Some diarrhea-producing agents are likely to act by increasing prostaglandin production.     

The origin of secondary microseism Love waves

The interaction of ocean surface waves produces pressure fluctuations at the seafloor capable of generating seismic waves in the solid Earth. The accepted mechanism satisfactorily explains secondary microseisms of the Rayleigh type, but it does not justify the presence of transversely polarized Love waves, nevertheless widely observed. An explanation for two-thirds of the worldwide ambient wave field has been wanting for over a century. Using numerical simulations of global-scale seismic wave propagation at unprecedented high frequency, here we explain the origin of secondary microseism Love waves. A small fraction of those is generated by boundary force-splitting at bathymetric inclines, but the majority is generated by the interaction of the seismic wave field with three-dimensional heterogeneity within the Earth. We present evidence for an ergodic model that explains observed seismic wave partitioning, a requirement for full-wave field ambient-noise tomography to account for realistic source distributions.

The surface of the Earth is continuously subjected to perturbing forces that generate seismic waves. Given that 70% of the surface of our planet is covered by oceans, seismic signals due to ocean storms represent the vast majority of seismic data recorded by seismometers on Earth (1). Such data carry information about the energy exchange between different Earth systems, allowing for probing our changing climate (2–4) as well as imaging the internal structure of the Earth (5). The strongest vibrations are called secondary microseisms, excited in the 0.1 to 0.3 Hz frequency range by nonlinear ocean wave–wave interaction (6, 7). They are predominantly composed of seismic surface waves, and Rayleigh waves dominate the vertical component of microseism records (8).The generation mechanism currently accepted for secondary microseisms explains the Rayleigh wave content of vertical-component noise records (9). Secondary microseisms are produced by pressure-like sources at the surface of the ocean. Rayleigh waves are excited below the seafloor due to constructive interference of P and SV body waves. At the ocean–crust interface, they are called Scholte waves when their phase velocity becomes smaller than the minimum phase velocity of the system (10). While at longer periods, ocean waves can directly couple with the seafloor and generate Love waves (11, 12), the generation mechanism of secondary microseisms cannot explain the presence of Love waves on the horizontal components of microseismic records. Observations of secondary microseism Love waves date back to the early (13) and middle (14) 20th century. A few recent studies based on high-quality digital data focused on quantifying the Love-to-Rayleigh ratio in the secondary microseism frequency range (SI Appendix, Table S1). They found that Love-to-Rayleigh ratios are frequency dependent (15) and show a predominance of Rayleigh waves (16, 17), with few exceptions (18).Hypotheses for the generation of secondary microseism Love waves envisage that they can be generated either in the region where the pressure power spectral density (PSD) is strong or along distinct propagation paths within the Earth. The first hypothesis is supported by the presence of bathymetric inclines in the source regions. Such bathymetry may lead to splitting of the vertical second-order pressure force in a component perpendicular to inclines—responsible for Rayleigh waves—and a component tangent to inclines—responsible for Love waves. The second hypothesis is supported by the presence of lateral heterogeneities within the Earth, which can lead to the generation of Love waves due to scattering and focusing/defocusing effects. Ref. 8 observed Love and Rayleigh waves coming from the same direction, concluding that Love waves do originate in the source region. On the other hand, ref. 19 noted that the greater the distance of propagation of Rayleigh waves, the larger the Love wave energy. In addition to these hypotheses, Love waves may originate from Rayleigh-to-Love wave conversion at the ocean–continent boundary, although early numerical simulations suggest that only a few percent of incident Rayleigh wave energy can be converted to Love wave energy (20). To date, no comprehensive theoretical investigations as to which mechanisms can lead to the observed secondary microseism Love waves have been conducted.     

Reference values of ECG parameters derived from 906 echocardiographically confirmed healthy Indian children: A population-based study from Gujarat

Introduction

There are few published studies on reference ranges of ECG parameters in children; some ethnic differences have been described.