The Relation between Hamstring Strain Injury and Physical Characteristics of Japanese Collegiate Sepak Takraw Players.

The aim of this study was to investigate the injuries in Japanese collegiate sepak takraw players. We primarily focused on hamstring strain injury (HSI), and investigated the associated physical characteristics. The study included 77 Japanese collegiate sepak takraw players who were interviewed; data were collected regarding injuries sustained by them during the game within the past year. The hip range of motion (ROM) was measured. The total number of injuries was 48 in a year. The rate of HSI was the highest (31.3%) among all the injuries. All HSIs occurred in the dominant leg because of the sunback spike. Using the Mann-Whitney U test, significant differences in age and sport-related experience were observed between the injured group and uninjured group. Upon using logistic regression analysis, the presence of a HSI was found to be associated with the sport-related experience (adjusted odds ratio [OR], 0.30; 95% confidence interval [CI], 0.12-0.77) and the hip extension ROM (adjusted OR, 0.81; 95% CI, 0.66-0.99) after adjusting for sex, sport-related experience, and the hip ROM. HSI is the most common injury in Japanese collegiate sepak takraw players. Short sport-related experience and small hip extension ROM are related with the occurrence of HSI.

Radiological abnormalities and low back pain in gymnasts.

Several studies have shown a higher prevalence of radiological abnormalities among gymnasts. However, the types of radiological abnormalities associated with low back pain (LBP) have not been clarified. The hypothesis was that significant relationships between radiological abnormalities and LBP may be revealed by discriminating between the types of MRI abnormalities while considering confounding factors. The subjects were 104 Japanese collegiate gymnasts (men, 70; women, 34). The presence of LBP was evaluated using the questionnaire developed by Osaka City University (OCU Test). Magnetic resonance imaging (MRI) abnormalities were evaluated using T1- and T2-weighted MRI. The prevalence of more than 1 MRI abnormality in gymnasts was 47.1% (49/104). The chi-square test showed that the incidence of lumbar disc degeneration (LDDG) and limbus vertebra was significantly greater in gymnasts with LBP than in gymnasts without LBP. By using logistic regression analysis to analyze the concomitant environmental variables, only LDDG (odds ratio, 2.70; 95% confidence interval, 1.10-6.66) was selected as a statistically significant variable accounting for LBP. In conclusion, LDDG is a predictor for LBP in Japanese collegiate gymnasts.

COL11A1 gene is associated with limbus vertebra in gymnasts.

Several studies have shown higher frequencies of radiological abnormalities among gymnasts. Recently, the gene encoding the α1 chain of type XI collagen, (COL11A1) (rs 1676486), was associated with lumbar disc herniation in the Japanese population. We hypothesized that there was a significant relationship between abnormal magnetic resonance imaging (MRI) findings of the lumbar spine and the COL11A1 4603C/T gene polymorphism in collegiate gymnasts. Our study participants included 103 Japanese collegiate gymnasts (70 men and 33 women). Radiological abnormalities were evaluated using T1- and T2-weighted MRI. Genotyping for COL11A1 was performed for all the participants. By using logistic regression analysis, we observed significant associations between limbus vertebra and age (adjusted odds ratio=0.51, 95% confidence interval: 0.27-0.96), sporting experience (adjusted odds ratio=1.49, 95% confidence interval: 1.14-1.94), and a TT genotype (adjusted odds ratio=7.83, 95% confidence interval: 1.33-46.03). We conclude that a TT genotype of COL11A1 polymorphism may be a significant risk factor for limbus vertebra in Japanese collegiate gymnasts.

The cartilage intermediate layer protein gene is associated with lumbar disc degeneration in collegiate judokas.

Lumbar disc degeneration is frequently seen in athletes. Lumbar disc diseases include a spectrum of diseases and/or symptoms, including lumbar disc degeneration. Some reports suggest an association between lumbar disc diseases and a functional single-nucleotide polymorphism (SNP;1184T/C, rs 2073711) of the cartilage intermediate layer protein ( CILP) gene. We hypothesized that lumbar disc degeneration occurrence may be significantly associated with SNP variants at the CILP gene in Japanese collegiate judo athletes. Eighty-nine Japanese judo athletes participated in this study. T2-weighted magnetic resonance imaging was used to define lumbar disc degeneration. Genotyping of the CILP gene (1184T/C) was performed using DNA sequencing. By using logistic regression analysis, significant associations of lumbar disc degeneration with the CILP C allele (odds ratio=4.1, 95% confidence interval: 1.57-10.71) and body weight (odds ratio=1.06, 95% confidence interval: 1.02-1.09) were observed. We conclude that the CILP gene 1184T/C polymorphism is a significant risk factor for lumbar disc degeneration occurrence in Japanese collegiate judo athletes.

An attempt to substitute the cell binding domain of human fibronectin in lambda phage J protein: computer design and expression.

We superimposed hydropathic indexes of the human fibronectin cell binding domain (CBD) on the lambda phage J protein by computer, and substituted 22 amino acids from the fibronectin CBD for a part of the lambda phage J protein. The fibronectin cell binding domain -Arg-Gly-Asp-Ser- (-RGDS-) localizes at the junction of hydrophobicity and hydrophilicity. We selected a similar hydrophobic-to-hydrophilic junction in the J protein region for substitution. This junction corresponds to 150 bp of the PstI fragment of J protein cDNA. We synthesized 150 bp of the relevant PstI fragment that includes the cell binding domain region. The region was then constructed by serial cloning as an expression vector, pJCBD. The vector pJCBD expressed the fused protein named JCBD (M(r) 32 kDa) in E coli XL1-BLUE. The expressed JCBD protein was identified by Western blot analysis in the extract of the pJCBD carrying bacterial lysate using both rabbit anti-lambda phage antiserum and anti-CBD of fibronectin antibody. The JCBD protein appeared to recognize retinoblast cell membrane RGDS-directed receptors, detected by enzyme-linked immuno-sorbent assay and also by binding competition assay with synthetic pentapeptides, Gly-Arg-Gly-Asp-Ser (GRGDS) and Gly-Arg-Gly-Glu-Ser (GRGES). The former competitor inhibited completely fibronectin CBD-dependent binding activity of JCBD, the latter had no inhibitory activity. These results suggest that certain functional proteins engineered by computer design between human fibronectin cell binding domain and lambda phage J protein can be produced.

Localization and synaptic effects of inhibitory vestibulocollic neurons activated by the posterior semicircular canal nerve in the cat.

Cellular locations, axonal projections, and synaptic effects of inhibitory vestibulocollic (VC) neurons activated by the ampullary nerve of the posterior semicircular canal (PCN) were studied in anesthetized cats. The inhibitory VC neurons were identified by their monosynaptic responses to PCN stimulation and by their antidromic responses to stimulation of the ipsilateral (i-) and contralateral (c-) neck extensor motoneuron pools, which are inhibitory targets of the PCN. They were classified as VCi (vestibulocollic neuron sending an axon to the i-neck extensor motoneuron pool) and VCc (vestibulocollic neuron sending an axon to the c-neck extensor motoneuron pool) neurons. Neither VCi nor VCc neurons were activated antidromically by localized stimulation of the ascending medial longitudinal fasciculus (asc. MLF) or the 3rd nuclei. Their cell somata were localized in the rostral part of the descending vestibular nucleus and the ventral part of the lateral vestibular nucleus. VCi and VCc neurons produced unitary IPSPs in neck extensor motoneurons in the C1 segment.

Effect of etchant variation on wet and dry dentin bonding primed with 4-META/acetone.

OBJECTIVE: To collect data that explains the advantage, if any, of wet bonding versus dry bonding to dentin, and to more clearly understand the mechanism of wet bonding. METHODS: Bovine dentin samples were prepared with #600-grit paper and were divided into four groups of six each. The first six specimens were etched with 10% citric acid and 3% ferric chloride for 10 s then rinsed and blot-dried (Gr. 1: 10-3:W). The second six were etched with 10% citric acid and 3% ferric chloride then rinsed and air-dried (Gr. 2: 10-3:D). The third six were etched with 10% citric acid for 10 s, rinsed and blot-dried (Gr. 3: 10-0:W). The fourth group of six samples was etched, rinsed and air-dried (Gr. 4: 10-0:D). All groups were primed with 5% 4-methacryloyloxyethyl trimellitate anhydride (4-META) in acetone for 60 s and an acrylic rod was bonded to the samples using a 4-META/methyl methacrylate (MMA)-tri-n-butyl borane (TBB) resin. The samples were fashioned into dumbbell-shaped specimens and stressed in tension until bond failure, to determine tensile bond strengths. Fractured surfaces were examined by scanning electron microscopy. RESULTS: The mean tensile bond strengths of specimen groups were found to be 18.9 (8.1) MPa (Gr. 1: 10-3:W), 18.1 (1.7) MPa (Gr. 2: 10-3:D), 11.9 (4.4) MPa (Gr. 3: 10-0:W) and 5.4 (2.8) MPa (Gr. 4: 10-0:D). There was no statistically significant difference between Grs. 1 and 2 (p > 0.01), or between Grs. 1 and 3 (p > 0.05). The TBS of Gr. 4 (10-0:D) was significantly lower than the others (p < 0.01). The 5% 4-META in acetone primer was apparently quite effective in improving monomer impregnation into demineralized dentin resulting in increased resin content within the hybridized dentin. SIGNIFICANCE: Effective dentin bonding depended upon the etchants employed. 10-0 etching and air-drying caused the demineralized dentin to collapse in which case wet bonding became necessary to obtain good TBS data. The specimens demineralized with 10-3 did not collapse, even when air-dried; consequently both wet and dry bonding proved effective for obtaining high tensile bond strength data.

Preoperative ampiroxicam reduces postoperative pain after hand surgery.

We performed a double blind randomised controlled study to assess whether the preoperative administration of ampiroxicam reduced the level of postoperative pain in 120 patients who underwent surgery to a hand under brachial plexus block. We found that preoperative (pre-emptive) administration of ampiroxicam significantly reduced the postoperative pain levels and the need for postoperative analgesia.

[Study of a particle counting method for index of masticatory efficiency].

The present report discusses our new simplified measuring method of masticatory efficiency by counting particles in the matter of making test materials and the standard equation for subjects with normal dentition. 1. Two kinds of hydrocolloid impression materials, reversible and irreversible, were used as the test materials. 2. For evaluating the shape of test materials, 12 subjects with normal dentition were tested and for calculating the standard equation, 108 subjects with normal dentition were tested. 3. Each subject was investigated by the simplified method of counting particles through a sieve system. The number of remaining particles on the mesh was calculated as a masticatory performance. 4. As indicated in a previous report by Dr. Ozawa about cubical test materials, columnar test materials are easier to make than the others and these were avairable for the present particle counting method for investigating masticatory efficiency. 5. We obtained the standard equation for both kinds of test material using 108 subjects with normal dentition. To simplify the measuring method, we selected the standard equation of a 5-mesh sieve with 10 strokes chewing for the index of masticatory efficiency. The standard equation of a 5-mesh sieve for both test materials are as follows; 1) Reversible hydrocolloid test material: Y = -1.605X+29.058 2) Irreversible hydrocolloid test material: Y = -1.116X+23.868 6. 5, 10-mesh sieve with 10 strokes chewing showed the smallest variation in the individual coefficient of variation with both kinds of test material.

Comparison of a new autocuring temporary acrylic resin with some existing products.

STATEMENT OF PROBLEM: Some problems of the self-curing or autopolymerizing resins may include color instability and dimensional inaccuracy. PURPOSE: This study compared the color and dimensional stability of the new autopolymerizing resin Unifast II, which combines a new activator with some existing products. RESULTS: The change in color (delta E value) of Unifast II resin was less than that demonstrated for four autopolymerizing resins (Unifast, Curefast, ADFA, and MIKY). Unifast II did not exhibit color change when stored in conditions below 37 degrees C. Unifast II also had a significantly better fit than the other four autopolymerizing resins (p < 0.01). No significant differences in transverse strength were observed among Unifast II, Unifast, and ADFA, but the Unifast II autopolymerizing resin maintained its color stability and dimensional accuracy without sacrificing its transverse strength.

Is there a three neuron arc in the cat utriculo-trochlear pathway?

The utriculo-ocular pathway was examined in decerebrated and anesthetized cats, in which all the vestibular afferents in the labyrinth, except for those innervating the utricular (UT) macula, had been transected. The UT nerve was stimulated with tungsten electrodes which were insulated except for 200 microns at the tips. Stimulation of the UT nerve evoked a small negative (N1) potential in the vestibular nuclei, with a threshold (N1T) less than 25 microA. The stimulus evoked disynaptic EPSPs in ipsilateral abducens (AB) motoneurons. The threshold and latency of the excitatory postsynaptic potentials (EPSPs) was 1.3 x N1T and 1.2 ms, respectively, in accordance with the data of Schwindt et al. (1973). On the other hand, EPSPs with a clear rising phase and short latency, suggesting the existence of a disynaptic pathway, were never observed in any contralateral trochlear (TR) motoneurons, even when triple shocks at intensities of up to 4 x N1T were applied. This stimulus strength was strong enough to activate the UT nerve. Thus it seems very likely that a disynaptic pathway from the UT nerve to contralateral TR motoneurons, is absent or very poorly organized.

Development of a two-piece artificial resin tooth specially designed for a metal occlusal surface.

The traditional denture fabrication technique using resin teeth with metal occlusal surfaces is rather complicated and time consuming. To improve this, a new two-piece artificial resin tooth has been developed. The teeth are arranged on the wax denture and processed in the usual manner. The patient is allowed to use the completed denture for a period of time to harmonize the occlusal surfaces with oral function. The occlusal portions of the teeth are then separated from the base and invested as a resin pattern for casting. The new cast occlusal portions are reset on the base portions with a resin adhesive.

EMG activities of two heads of the human lateral pterygoid muscle in relation to mandibular condyle movement and biting force.

Electromyographic (EMG) activities of the superior (SUP) and inferior heads (INF) of the lateral pterygoid muscle (LPT) were recorded in humans during voluntary stepwise changes in biting force and jaw position that were adopted to exclude the effects of acceleration and velocity of jaw movements on the muscle activity. The SUP behaved like a jaw-closing muscle and showed characteristic activity in relation to the biting force. It showed a considerable amount of background activity (5-32% of the maximum) even in the intercuspal position without teeth clenching and reached a nearly maximum activity at relatively lower biting-force levels than the jaw-closing muscles during increment of the biting force. Stretch reflexes were found in the SUP, the function of which could be to stabilize the condyle against the biting force that pulls the condyle posteriorly. This notion was verified by examining the biomechanics on the temporomandibular joint. The complex movements of the mandibular condyle in a sagittal plane were decomposed into displacement in the anteroposterior direction (Ac) and angle of rotation (RAc) around a kinesiological specific point on the condyle. In relation to Ac, each head of the LPT showed quite a similar behavior to each other in all types of jaw movements across all subjects. Working ranges of the muscle activities were almost constant (Ac <3 mm for the SUP and Ac >3 mm for the INF). The amount of EMG activity of the SUP changed in inverse proportion to Ac showing a hyperbola-like relation, whereas that of the INF changed rather linearly. The EMG amplitude of the SUP showed a quasilinear inverse relation with RAc in the hinge movement during which the condyle rotated with no movement in the anteroposterior direction. This finding suggests that the SUP controls the angular relationship between the articular disk and the condyle. On the other hand, the position of the disk in relation to the maxilla, not to the condyle, is controlled indirectly by the INF because the disk is attached to the condyle by tendinous ligaments.

Axonal trajectories of inhibitory vestibulocollic neurons activated by the anterior semicircular canal nerve and their synaptic effects on neck motoneurons in the cat.

Somatic location, axonal trajectories and synaptic effects of inhibitory vestibulocollic neurons which were activated by selective stimulation of the anterior semicircular canal nerve (ACN) were studied in the anesthetized cat. ACN stimulation evoked disynaptic inhibitory postsynaptic potentials (IPSPs) in neck flexor motoneurons. This was seen in all the (64/64) tested motoneurons innervating the ipsilateral (i-) longus capitis (LC) and the i-sternocleidomastoideus (SCM) muscles and in 86% (38/44) of the motoneurons innervating the contralateral (c-) LC muscle. The inhibitory relay neurons, identified by orthodromic and antidromic responses to stimulation of the ACN and the i- and c-LC motoneuron pools, were classified as VCi (vestibulocollic neurons sending an axon to the i-LC motoneuron pool) and VCc (vestibulocollic neurons sending an axon to the c-LC motoneuron pool) neurons. Neither VCi nor VCc neurons were activated antidromically by localized stimulation of the ascending medial longitudinal fasciculus (asc. MLF) or the 3rd nuclei. They were located in the medial, descending and ventral lateral vestibular nuclei. It was also observed that VCi neurons produced unitary IPSPs in i-LC and i-SCM motoneurons in the C1 segment. Inhibitory synapses were estimated to be on the cell somata and/or the proximal dendrites of the motoneurons.

[Evaluation of masticatory efficiency and the analysis of occlusal pattern factors using computer image processing method].

The purpose of this study was to evaluate the newly developed computer-assisted image processing method. We applied this method for the evaluation of masticatory efficiency and the analysis of occlusal pattern factors: the number and the size of occlusal contact areas, the number of and the size of the projected facets. We compared this new method with our conventional one which is the simplified particle counting method using a sieve and measuring the occlusal pattern factors with a planimeter. The results were as follows: 1. It is possible to count the number of particles within an optional range of size with the new method. 2. The new method may be used with minimum error for the measurement of occlusal pattern factors. We believe that this newly developed computer-assisted image processing method can be put to practical use for clinical evaluation of masticatory efficiency and analysis of occlusal pattern factors.

[Survey on oral and maxillofacial injuries in contact sports and diffusion of mouthguards].

Recent reports have shown an increase of oral and maxillofacial injuries caused by sports activities. In European and American countries, mouthguards are the popular measure against these injuries. The purpose of this study was to survey the rate of incidence of oral and maxillofacial injuries caused by contact sports, the diffusion and the evaluation of mouthguards and the interest in mouthguards in Japan. Questionnaires were sent to 244 Rugby football teams in Aichi prefecture and 27 American football teams in the Tokai area. We received replies from 153 Rugby football teams and 17 American football teams, and the results were as follows: 1) The rate of incidence of oral and maxillofacial injuries was 239 players out of 4721 players, which means 5.1% in Rugby football and 22 players out of 428 players, which means 5.1% in American football. 2) The diffusion of mouthguards was 20 out of 153 teams in Rugby football and 16 out of 17 teams in American football. And most of them are using commercially available mouthguards. 3) Almost all teams were not satisfied with their mouthguards and complained of speaking difficulties, discomfort and easy dislocation. 4) Almost all teams desire the improvement of mouthguards. 5) Teams with no experience of mouthguards were very much interested in the use of mouthguards but they do not have enough information about mouthguards. 6) We have to enlighten players and their instructors about mouthguards and diffuse the use of mouthguards more positively to contact sports players.

The neuronal organization of horizontal semicircular canalactivated inhibitory vestibulocollic neurons in the cat.

1. The somatic location and axonal projections of inhibitory vestibular nucleus neurons activated by the horizontal semicircular canal nerve (HCN) were studied in anesthetized cats. Cats were anesthetized with ketamine hydrochloride and pentobarbital sodium. 2. Intracellular recordings were obtained from 11 neck extensor motoneurons which were identified by antidromic activation from the dosal rami (DR) in the C1 segment. Stimulation of the ipsilateral (i-) HCN and the ipsilateral abducens (AB) nucleus evoked IPSPs in the motoneurons. These IPSPs were fully or partially occluded when they were evoked simultaneously. 3. Intracellular recordings were obtained from 8 AB motoneurons. Stimulation of the i-HCN and the i-C1DR motoneuron pool evoked IPSPs in the AB motoneurons. These IPSPs were also partially occluded when they were evoked simultaneously, which implied that some HCN-activated neurons inhibit both i-AB motoneurons and ipsilateral neck motoneurons. 4. Unit activity was extracellularly recorded from 30 vestibular neurons that were activated monosynaptically by i-HCN stimulation. Their axonal projections were determined by stimulating the i-AB nucleus and the i-C1DR motoneuron pool. Eight neurons were activated by both stimuli, and were termed vestibulooculo-collic (VOC) neurons. Their axonal branching was examined by means of local stimulation in and around the i-AB nucleus and the i-C1DR motoneuron pool. Eighteen neurons were antidromically activated from the i-C1DR motoneuron pool but not from the i-AB nucleus. These were termed vestibulo-collic (VC) neurons. Four neurons were activated from the i-AB nucleus but not from the ventral funiculus in the C1 segment, and were termed vestibulo-ocular (VO) neurons.(ABSTRACT TRUNCATED AT 250 WORDS)

The healing process of chronic colitis in rats, induced by 2,4,6-trinitrobenzene sulfonic acid, with special reference to the role of fibronectin.

BACKGROUND: The healing process of rat chronic colitis was investigated to evaluate the role of fibronectin produced by fibroblasts in the healing tissue. METHODS: Chronic colitis was produced by intrarectal instillation of 2,4,6-trinitrobenzene sulfonic acid. The healing process was observed by light and electron microscopy and immunocytochemistry. Time course of fibronectin mRNA expression was measured by Northern blot hybridization. RESULTS: By light and electron microscopy, an abundance of young fibroblasts had gathered at the healing tissue and were involved in incorporation into the endothelium of the preexisting vessels, as vasoformative cells, and in transformation to new muscle cells in muscular regeneration. Such processes became pronounced from day 3 and persisted for 6 weeks. Immunocytochemical data showed that fibronectin, produced in the rough endoplasmic reticulum of the fibroblasts and released to the extracellular surface, played inductive roles in the movement and aggregation of such cells and in their contacts with neighboring endothelial cells of the preexisting capillaries. Northern hybridization showed that mRNA coding for fibronectin rapidly reached maximum on day 3 and gradually decreased almost to the control level at 6 weeks. CONCLUSIONS: These observations elucidate the role of young fibroblasts, as multipotent cells, and of fibronectin in acceleration of the healing process in this model of chronic colitis.

[Properties of experimental high abrasion resistance plastic teeth].

High abrasion resistance plastic teeth made of microfilled urethane dimethacrylate resin were developed around ten years ago. In recent years, several of this same type of resin teeth were developed and introduced commercially in Japan. Many studies have reported the properties of restorative resin materials, but few comparative studies have been conducted among the various resin teeth on the market. The purpose of this study was to compare the basic physical properties of conventional acrylic resin teeth as dental materials with an experimental high abrasion resistance plastic for posterior teeth made of microfilled urethane dimethacrylate. In addition, we compared the properties of the experimental teeth with the other high abrasion resistance plastic teeth including a comparative study of anterior and posterior teeth already on the market. The results indicated that basic physical properties of the experimental posterior resin teeth were better than those of the conventional acrylic resin teeth, but the staining resistance of the former was a little lower than that of the latter. Further, the experimental posterior teeth appeared to have physical properties equal to those of other resin teeth of the same type, but the staining resistance of the experimental resin teeth was higher.