A new approach to estimation of the number of central synapse(s) included in the H-reflex

Background  

Among the main clinical applications of the H-reflex are the evaluation of the S1 nerve root conductivity such as radiculopathy and measurement of the excitability of the spinal motoneurons in neurological conditions. An attempt has been made to reduce the pathway over which H-reflex can be obtained in a hope to localize a lesion to the S1 nerve root, so the S1 central loop has been suggested. The main goal of this study is the estimation of the H-reflex number of synapse(s) for better understanding of the physiology of this practical reflex.     

Male predominance of pneumonia and hospitalization in pandemic influenza A (H1N1) 2009 infection

Background

Based on our clinical experience, the H-reflex amplitude asymmetry might be an earlier sign of nerve root involvement than latency in patients with S1 radiculopathy. However, no data to support this assumption are available. The purpose of this study was to review and report the electrophysiological changes in H-reflex amplitude and latency in patients with radiculopathy in order to determine if there is any evidence to support the assumption that H-reflex amplitude is an earlier sign of nerve root involvement than latency.

Results

Patients with radiculopathy showed significant amplitude asymmetry when compared with healthy controls. However, latency was not always significantly different between patients and healthy controls. These findings suggest nerve root axonal compromise that reduced reflex amplitude earlier than the latency parameter (demyelination) during the pathologic processes.

Conclusion

Contrary to current clinical thought, H-reflex amplitude asymmetry is an earlier sign/parameter of nerve root involvement in patients with radiculopathy compared with latency.     

A comparison of H-reflex in the triceps surae muscle group in patients with S1 radiculopathy

Despite differences in the anatomical and physiological characteristics of the medial gastrocnemius (MG), lateral gastrocnemius (LG), and soleus (Sol) muscles, it is common practice to investigate them as single triceps surae H-reflex recordings. The aim of this study was to compare the latencies of H-reflex recordings from the Sol, MG, and LG in patients with explicit magnetic resonance imaging (MRI) evidence of unilateral S1 radiculopathy and also compare their diagnostic yield in varied clinical characteristics (i.e., symptom duration and severity of involvement). We found a significant difference between H-reflex latencies of Sol and the two others (p?相似文献   

Single trial somatosensory evoked potential extraction with ARX filtering for a combined spinal cord intraoperative neuromonitoring technique

Background  

When spinal cord functional integrity is at risk during surgery, intraoperative neuromonitoring is recommended. Tibial Single Trial Somatosensory Evoked Potentials (SEPs) and H-reflex are here used in a combined neuromonitoring method: both signals monitor the spinal cord status, though involving different nervous pathways. However, SEPs express a trial-to-trial variability that is difficult to track because of the intrinsic low signal-to-noise ratio. For this reason single trial techniques are needed to extract SEPs from the background EEG.     

Evaluation of lumbar enlargement motor neuron excitability: Comparison between H-reflex and transcutaneous spinal cord stimulation

Multisegmental muscle responses (MMR) are reflexes in the leg muscles evoked by transcutaneous electrical spinal cord stimulation over the Th11–Th12 vertebrae. We have used MMR to evaluate the excitability of lumbosacral motor neurons in individuals having paraplegia of low limbs. Ten individuals were tested using H-reflexes and MMR bilaterally before (n ₀ = 20) and during 4-weeks course of rehabilitation (n=76). The H-reflex and MMR of m. gastrocnemius lateralis were obtained in: 15 and 13 cases out of 20, respectively. Both reflexes were recorded in 11 and were absent in 3 cases, matched up to 70% of recordings. In dynamic, the both methods were 100% reproducible and the responses’ amplitude varied in similar directions in 67% of records. The data confirm the validity and reproducibility of the MMR for evaluation of the motor neurons excitability in lumbosacral cord. The H-reflex magnitude shows moderate correlation with MMR in m. gastrocnemius lateralis (r = 0.59, p < 0.001), and weak correlation with MMR in mm. rectus femoris, biceps femoris, and tibialis anterior (r < 0.40, p < 0.001). These findings do not allow extrapolate the results from the H-reflex measurement on the state of lumbosacral cord on the whole. At the same time, measurements of the MMR allow estimate simultaneously the excitability of motor pools innervating several muscle groups. This gives the possibility to assess the functional state of the motor neurons in the lumbosacral cord for clinical and experimental studies, including the spinal cord damage.     

Repeatability of corticospinal and spinal measures during lengthening and shortening contractions in the human tibialis anterior muscle

Elements of the human central nervous system (CNS) constantly oscillate. In addition, there are also methodological factors and changes in muscle mechanics during dynamic muscle contractions that threaten the stability and consistency of transcranial magnetic stimulation (TMS) and perpherial nerve stimulation (PNS) measures.

Purpose

To determine the repeatability of TMS and PNS measures during lengthening and shortening muscle actions in the intact human tibialis anterior.

Methods

On three consecutive days, 20 males performed lengthening and shortening muscle actions at 15, 25, 50 and 80% of maximal voluntary contraction (MVC). The amplitude of the Motor Evoked Potentials (MEPs) produced by TMS was measured at rest and during muscle contraction at 90° of ankle joint position. MEPs were normalised to Mmax determined with PNS. The corticospinal silent period was recorded at 80% MVC. Hoffman reflex (H-reflex) at 10% isometric and 25% shortening and lengthening MVCs, and V-waves during MVCs were also evoked on each of the three days.

Results

With the exception of MEPs evoked at 80% shortening MVC, all TMS-derived measures showed good reliability (ICC = 0.81–0.94) from days 2 to 3. Confidence intervals (CI, 95%) were lower between days 2 and 3 when compared to days 1 and 2. MEPs significantly increased at rest from days 1 to 2 (P = 0.016) and days 1 to 3 (P = 0.046). The H-reflex during dynamic muscle contraction was reliable across the three days (ICC = 0.76–0.84). V-waves (shortening, ICC = 0.77, lengthening ICC = 0.54) and the H-reflex at 10% isometric MVC (ICC = 0.66) was generally less reliable over the three days.

Conclusion

Although it is well known that measures of the intact human CNS exhibit moment-to-moment fluctuations, careful experimental arrangements make it possible to obtain consistent and repeatable measurements of corticospinal and spinal excitability in the actively lengthening and shortening human TA muscle.     

Morphological Alterations in Gastrocnemius and Soleus Muscles in Male and Female Mice in a Fibromyalgia Model

Background

Fibromyalgia (FM) is a chronic musculoskeletal pain disorder, characterized by chronic widespread pain and bodily tenderness and is often accompanied by affective disturbances, however often with unknown etiology. According to recent reports, physical and psychological stress trigger FM. To develop new treatments for FM, experimental animal models for FM are needed to be development and characterized. Using a mouse model for FM including intermittent cold stress (ICS), we hypothesized that ICS leads to morphological alterations in skeletal muscles in mice.

Methods

Male and female ICS mice were kept under alternating temperature (4°C/room temperature [22°C]); mice constantly kept at room temperature served as control. After scarification, gastrocnemius and soleus muscles were removed and snap-frozen in liquid nitrogen–cooled isopentane or fixed for electron microscopy.

Results

In gastrocnemius/soleus muscles of male ICS mice, we found a 21.6% and 33.2% decrease of fiber cross sectional area (FCSA), which in soleus muscle concerns the loss of type IIa and IIx FCSA. This phenomenon was not seen in muscles of female ICS mice. However, this loss in male ICS mice was associated with an increase in gastrocnemius of the density of MIF⁺ (8.6%)-, MuRF⁺ (14.7%)-, Fbxo32⁺ (17.8%)-cells, a 12.1% loss of capillary contacts/muscle fiber as well as a 30.7% increase of damaged mitochondria in comparison with male control mice. Moreover, significant positive correlations exist among densities (n/mm²) of MIF⁺, MuRF⁺, Fbxo32⁺-cells in gastrocnemius/ soleus muscles of male ICS mice; these cell densities inversely correlate with FCSA especially in gastrocnemius muscle of male ICS mice.

Conclusion

The ICS-induced decrease of FCSA mainly concerns gastrocnemius muscle of male mice due to an increase of inflammatory and atrogenic cells. In soleus muscle of male ICS and soleus/gastrocnemius muscles of female ICS mice morphological alterations seem to occur not at all or delayed. The sex-specificity of findings, which is not easily reconciled with the epidemiology of FM (female predominance), implicate that gastrocnemius muscle of male ICS mice should preferentially be used for future investigations with FM. Moreover, we suggest to investigate morphological and/or molecular alterations at different time-points (up to two weeks) after ICS.     

Effects of age and leg length upon central loop of the Gastrocnemius-soleus H-reflex latency

Background  

central loop of the gastrocnemius-soleus H-reflex latency (T_c) that looks promising in the diagnosis of S1 radiculopathy; has been investigated in a few studies and only two of them have focused on the constitutional factors affecting it. Although leg length has been shown to contribute to the T_c, the role of age is controversial. More confusing, none of the previously performed studies have used strict criteria to rule out subclinical neuropathy, so the results could be misleading. This study has been performed to determine the influence of leg length and age on T_c among a carefully selected group of healthy volunteers.     

Impaired H-Reflex Gain during Postural Loaded Locomotion in Individuals Post-Stroke

Objective

Successful execution of upright locomotion requires coordinated interaction between controllers for locomotion and posture. Our earlier research supported this model in the non-impaired and found impaired interaction in the post-stroke nervous system during locomotion. In this study, we sought to examine the role of the Ia afferent spinal loop, via the H-reflex response, under postural influence during a locomotor task. We tested the hypothesis that the ability to increase stretch reflex gain in response to postural loads during locomotion would be reduced post-stroke.

Methods

Fifteen individuals with chronic post-stroke hemiparesis and 13 non-impaired controls pedaled on a motorized cycle ergometer with specialized backboard support system under (1) seated supported, and (2) non-seated postural-loaded conditions, generating matched pedal force outputs of two levels. H-reflexes were elicited at 90°crank angle.

Results

We observed increased H-reflex gain with postural influence in non-impaired individuals, but a lack of increase in individuals post-stroke. Furthermore, we observed decreased H-reflex gain at higher postural loads in the stroke-impaired group.

Conclusion

These findings suggest an impaired Ia afferent pathway potentially underlies the defects in the interaction between postural and locomotor control post-stroke and may explain reduced ability of paretic limb support during locomotor weight-bearing in individuals post-stroke.

Significance

These results support the judicious use of bodyweight support training when first helping individuals post-stroke to regain locomotor pattern generation and weight-bearing capability.     

Effects of Methane-Rich Saline on the Capability of One-Time Exhaustive Exercise in Male SD Rats

Purpose

To explore the effects of methane-rich saline (CH₄ saline) on the capability of one-time exhaustive exercise in male SD rats.

Methods

Thirty rats were equally divided into to three groups at random: control group (C), placebo group (P) and methane saline group (M). Rats in M group underwent intraperitoneal injection of CH₄ saline, and the other two groups simultaneously underwent intraperitoneal injection of normal saline. Then, the exercise capability of rats was tested through one-time exhaustive treadmill exercise except C group. Exercise time and body weight were recorded before and after one-time exhaustive exercise. After exhaustive exercise, the blood and gastrocnemius samples were collected from all rats to detect biochemical parameters in different methods.

Results

It was found that the treadmill running time was significantly longer in rats treated with CH₄ saline. At the same time, CH₄ saline reduced the elevation of LD and UN in blood caused by one-time exhaustive exercise. The low level of blood glucose induced by exhaustive exercise was also normalized by CH₄ saline. Also CH₄ saline lowered the level of CK in plasma. Furthermore, this research indicated that CH₄ saline markedly increased the volume of T-AOC in plasma and alleviated the peak of TNF-α in both plasma and gastrocnemius. From H&E staining, CH₄ saline effectively improved exercise-induced structural damage in gastrocnemius.

Conclusions

CH₄ saline could enhance exercise capacity in male SD rats through increase of glucose aerobic oxidation, improvement of metabolic clearance and decrease of exhaustive exercise-induced gastrocnemius injury.     

Growth,acid production and bacteriocin production by probiotic candidates under simulated colonic conditions

Aims

The aim of this study is to evaluate the capacity of three bacteriocin producers, namely Lactococcus lactis subsp. lactis biovar diacetylactis UL719 (nisin Z producer), L. lactis ATCC 11454 (nisin A producer) and Pediococcus acidilactici UL5 (pediocin PA‐1 producer), and to grow and produce their active bacteriocins in Macfarlane broth, which mimics the nutrient composition encountered in the human large intestine.

Methods and Results

The three bacteriocin‐producing strains were grown in Macfarlane broth and in De Man–Rogosa–Sharpe (MRS) broth. For each strain, the bacterial count, pH drop and production of organic acids and bacteriocins were measured for different period of time. The ability of the probiotic candidates to inhibit Listeria ivanovii HPB 28 in co‐culture in Macfarlane broth was also examined. Lactococcus lactis subsp. lactis biovar diacetylactis UL719, L. lactis ATCC 11454 and Ped. acidilactici UL5 were able to grow and produce their bacteriocins in MRS broth and in Macfarlane broth. Each of the three candidates inhibited L. ivanovii HPB 28, and this inhibition activity was correlated with bacteriocin production. The role of bacteriocin production in the inhibition of L. ivanovii in Macfarlane broth was confirmed for Ped. acidilactici UL5 using a pediocin nonproducer mutant.

Conclusions

The data provide some evidence that these bacteria can produce bacteriocins in a complex medium with carbon source similar to those found in the colon.

Significance and Impact of the Study

This study demonstrates the capacity of lactic acid bacteria to produce their bacteriocins in a medium simulating the nutrient composition of the large intestine.     

Production and characterization of recombinant pertactin, fimbriae 2 and fimbriae 3 from Bordetella pertussis

Background  

Bordetella pertussis is a causative agent of pertussis or whooping cough in humans. Pertactin (Prn), fimbriae 2 (Fim2) and fimbriae 3 (Fim3) of B. pertussis are important virulence factors and immunogens which have been included in some acellular pertussis vaccines. In this present study, we cloned, expressed and purified Prn, Fim2 and Fim3, respectively. The immunogeniCity and protective efficacy of the three recombinant proteins (rPrn, rFim2 and rFim3) were investigated in mouse model.     

Changes in αB-crystallin,tubulin, and MHC isoforms by hindlimb unloading show different expression patterns in various hindlimb muscles

[Purpose]

αB-crystallin is a small heat shock protein that acts as a molecular chaperone under various stress conditions. Microtubules, which consist of tubulin, are related to maintain the intracellular organelles and cellular morphology. These two proteins have been shown to be related to the properties of different types of myofibers based on their contractile properties. The response of these proteins during muscular atrophy, which induces a myofibril component change, is not clearly understood.

[Methods]

We performed 15 days of hindlimb unloading on rats to investigate the transitions of these proteins by analyzing their absolute quantities. Protein contents were analyzed in the soleus, plantaris, and gastrocnemius muscles of the unloading and control groups (N = 6).

[Results]

All three muscles were significantly atrophied by hindlimb unloading (P < 0.01): soleus (47.5%), plantaris (16.3%), and gastrocnemius (21.3%) compared to each control group. αB-crystallin was significantly reduced in all three examined unloaded hindlimb muscles compared to controls (P < 0.01) during the transition of the myosin heavy chain to fast twitch muscles. α-Tubulin responded only in the unloaded soleus muscle. Muscle atrophy induced the reduction of αB-crystallin and α-tubulin expressions in plantar flexor muscles with a shift to the fast muscle fiber compared to the control.

[Conclusion]

The novel finding of this study is that both proteins, αB-crystallin and α-tubulin, were downregulated in slow muscles (P < 0.01); However, α-tubulin was not significantly reduced compared to the control in fast muscles (P < 0.01).     

The flavan-3-ol fraction of cocoa powder suppressed changes associated with early-stage metabolic syndrome in high-fat diet-fed rats

Aims

Previous epidemiological studies have suggested that ingestion of chocolate reduces the risk of cardiovascular disease. In the present study, we examined the effects of flavan-3-ols derived from cocoa on blood pressure, lipolysis, and thermogenesis in rats fed a high-fat diet and that showed early signs of metabolic syndrome.

Main methods

The rats were divided into three groups, and fed either normal diet (normal), 60% fat high-fat diet (HFD), or HFD containing 0.2% flavan-3-ols (HFD-flavan) for 4 weeks. At the end of the feeding period, blood pressure was measured and animals were sacrificed under anesthesia. Lipolysis and thermogenesis-related protein levels were measured in several tissues by Western blotting, and mitochondrial DNA copy number was measured by RT-PCR.

Key findings

Mean blood pressure and epididymal adipose tissue weight of HFD-flavan were significantly lower compared with those of HFD. Uncoupling protein (UCP)1 in brown adipose tissue and UCP3 in gastrocnemius of HFD-flavan were significantly increased compared with those of HFD group. Carnitine palmitoyltransferase (CPT) 2 levels in liver and medium-chain acyl-CoA dehydrogenase (MCAD) levels in gastrocnemius and liver were significantly increased by the supplementation of flavan-3-ols.

Significance

In addition to having hypotensive effects, flavan-3-ols enhance thermogenesis and lipolysis and consequently reduce white adipose tissue weight gain in response to high-fat diet feeding.     

Complete plastid genome sequences of Drimys, Liriodendron, and Piper : implications for the phylogenetic relationships of magnoliids

Background  

The magnoliids with four orders, 19 families, and 8,500 species represent one of the largest clades of early diverging angiosperms. Although several recent angiosperm phylogenetic analyses supported the monophyly of magnoliids and suggested relationships among the orders, the limited number of genes examined resulted in only weak support, and these issues remain controversial. Furthermore, considerable incongruence resulted in phylogenetic reconstructions supporting three different sets of relationships among magnoliids and the two large angiosperm clades, monocots and eudicots. We sequenced the plastid genomes of three magnoliids, Drimys (Canellales), Liriodendron (Magnoliales), and Piper (Piperales), and used these data in combination with 32 other angiosperm plastid genomes to assess phylogenetic relationships among magnoliids and to examine patterns of variation of GC content.     

Neuromuscular function during drop jumps in young and elderly males

The Hoffman reflex (H-reflex), indicating alpha-motoneuron pool activity, has been shown to be task – and in resting conditions – age dependent. How aging affects H-reflex activity during explosive movements is not clear at present. The purpose of this study was to examine the effects of aging on H-reflexes during drop jumps, and its possible role in drop jump performance. Ten young (26.8 ± 2.7 years) and twenty elderly (64.2 ± 2.7 years) subjects participated in the study. Maximal drop jump performance and soleus H-reflex response (H/M jump) 20 ms after ground contact were measured in a sledge ergometer. Maximal H-reflex, maximal M-wave, Hmax/Mmax-ratio and H-reflex excitability curves were measured during standing rest. Although in young the H-reflex response (Hmax/Mmax) was 6.5% higher during relaxed standing and 19.7% higher during drop jumps (H jump/M jump) than in the elderly group, these differences were not statistically significant. In drop jumps, the elderly subjects had lower jumping height (30.4%, p < 0.001), longer braking time (32.4%, p < 0.01), lower push-off force (18.0%, p < 0.05) and longer push-off time (31.0% p < 0.01). H jump/M jump correlated with the average push-off force (r = 0.833, p < 0.05) and with push-off time (r = ?0.857, p < 0.01) in young but not in the elderly. Correlations between H-reflex response and jumping parameters in young may indicate different jumping and activation strategies in drop jumps. However, it does not fully explain age related differences in jumping performance, since age related differences in H-reflex activity were non-significant.     

Regional differences in expression of VEGF mRNA in rat gastrocnemius following 1 hr exercise or electrical stimulation

Background  

Vascular endothelial growth factor (VEGF) mRNA levels increase in rat skeletal muscle after a single bout of acute exercise. We assessed regional differences in VEGF₁₆₅ mRNA levels in rat gastrocnemius muscle using in situ hybridization after inducing upregulation of VEGF by treadmill running (1 hr) or electrical stimulation (1 hr). Muscle functional regions were defined as oxidative (primarily oxidative fibers, I and IIa), or glycolytic (entirely IIb or IId/x fibers). Functional regions were visualized on muscle cross sections that were matched in series to slides processed through in situ hybridization with a VEGF₁₆₅ probe. A greater upregulation in oxidative regions was hypothesized.     

Test–retest reliability of the soleus H-reflex is affected by joint positions and muscle force levels

The purpose of this study was to determine the test–retest reliability of the soleus (SOL) H-reflex during rest and isometric contractions at 10%, 30%, and 50% of the maximal voluntary force (MVC) at the ankle joint angles of neutral (0°), plantarflexion (20°), and dorsiflexion (?20°) respectively, in a sitting position. Ten healthy participants, with mean age of 24.9 ± 5.0 (SD) years, height 168.3 ± 8.8 cm, weight 62.7 ± 12.3 kg, were tested for the SOL H-reflex (H_max) on two separate occasions within 7 days. The intraclass correlation coefficient (ICC) for the test–retest of the SOL H-reflex during rest was found to be high at ankle joint angle of neutral (ICC = 0.92) and plantarflexion (0.96), and moderate at dorsiflexion (0.75). Inconsistent ICC values (range from 0.62 to 0.97) were found during the submaximal voluntary contractions at the three ankle joint positions. High ICCs were also found in H_max/M_max ratio at neutral (0.86), plantarflexion (0.96), and dorsiflexion (0.84) positions. It was concluded that the test–retest reliability of the SOL H-reflex was affected by the intensity of voluntary contraction and ankle joint position. The H-reflex demonstrated a higher reliability at the neutral and plantarflexion positions than that at the dorsiflexion position during rest, and a higher reliability at 10% MVC than that at 30% and 50% MVC.     

Seroprevalence of Helicobacter pylori in Korea: A multicenter,nationwide study conducted in 2015 and 2016

Background

The Korean College of Helicobacter and Upper Gastrointestinal Research has studied Helicobacter pylori (H. pylori) prevalence since 1998 and found a dynamic change in its prevalence in Korea. The aim of this study was to determine the recent H. pylori prevalence rate and compare it with that of previous studies according to socioeconomic variables.

Methods

We planned to enroll 4920 asymptomatic Korean adults from 21 centers according to the population distribution of seven geographic areas (Seoul, Gyeonggi, Gangwon, Chungcheong, Kyungsang, Cholla, and Jeju). We centrally collected serum and tested H. pylori serum IgG using a chemiluminescent enzyme immunoassay.

Results

We analyzed 4917 samples (4917/4920 = 99.9%) from January 2015 to December 2016. After excluding equivocal serologic results, the H. pylori seropositivity rate was 51.0% (2414/4734). We verified a decrease in H. pylori seroprevalence compared with previous studies performed in 1998, 2005, and 2011 (P < .0001). The H. pylori seroprevalence rate differed by area: Cholla (59.5%), Chungcheong (59.2%), Kyungsang (55.1%), Jeju (54.4%), Gangwon (49.1%), Seoul (47.4%), and Gyeonggi (44.6%). The rate was higher in those older than 40 years (38.1% in those aged 30‐39 years and 57.7% in those aged 40‐49 years) and was lower in city residents than in noncity residents at all ages.

Conclusions

Helicobacter pylori seroprevalence in Korea is decreasing and may vary according to population characteristics. This trend should be considered to inform H. pylori‐related policies.     

Disease-specific definitions of vitamin D deficiency need to be established in autoimmune and non-autoimmune chronic diseases: a retrospective comparison of three chronic diseases

Introduction  

We compared the odds of vitamin D deficiency in three chronic diseases: systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), and type 2 diabetes (T2DM), adjusting for medications, demographics, and laboratory parameters, common to all three diseases. We also designed multivariate models to determine whether different factors are associated with vitamin D deficiency in different racial/ethnic groups.