Effects of interocclusal distance on bite force and masseter EMG in healthy participants.

The aim of this study was to investigate effects of interocclusal distance (IOD) on bite force and masseter electromyographic (EMG) activity during different isometric contraction tasks. Thirty-one healthy participants (14 women and 17 men, 21·2 ± 1·8 years) were recruited. Maximal Voluntary Occlusal Bite Force (MVOBF) between the first molars and masseter EMG activity during all the isometric-biting tasks were measured. The participants were asked to bite at submaximal levels of 20%, 40%, 60% and 80% MVOBF with the use of visual feedback. The thickness of the force transducer was set at 8, 12, 16 and 20 mm (= IOD), and sides were tested in random sequence. MVOBF was significantly higher at 8 mm compared with all other IODs (P < 0·001). Only in women, IOD always had significant influence on the corresponding root-mean-square (RMS) value of EMG (P < 0·011). When biting was performed on the ipsilateral side to the dominant hand, the working side consistently showed higher masseter EMG activity compared with the balancing side (P < 0·020). On the contralateral side, there was no difference between the masseter EMG at any IODs. The results replicated the finding that higher occlusal forces can be generated between the first molars at shorter IODs. The new finding in this study was that an effect of hand dominance could be found on masseter muscle activity during isometric biting. This may suggest that there can be a general dominant side effect on human jaw muscles possibly reflecting differences in motor unit recruitment strategies.

Does restriction of mandibular movements during sleep influence jaw-muscle activity?

To investigate the effect of restriction of mandibular movements during sleep on jaw-muscle electromyographic (EMG) activity. Eleven healthy subjects (four men and seven women; age, 25·9 ± 3·1 years) with self-reports of sleep bruxism participated in three randomised sessions with three different types of oral appliances: (i) full-arch maxillary and mandibular appliances which did not allow any mandibular movement, that is, restrictive oral appliance (restrict-MMOA), (ii) full-arch maxillary and mandibular oral appliances (free-MMOA) with no restrictions of mandibular movements and (iii) conventional full-arch flat stabilisation appliance, that is, maxillary oral appliance (free-MOA). Baseline recordings (1st EMG recording) of jaw-muscle activity during sleep without any oral appliance were performed and followed by 1 week of nightly use of each oral appliance (three sessions). During the last night in each session, jaw-muscle activity was recorded (2nd, 3rd and 4th EMG recordings) and compared to baseline values. All EMG data were analysed in accordance with the gold-standard diagnostic method. The average jaw-muscle activity expressed as number of EMG episodes and bursts per hour sleep was significantly reduced during any combination of appliance compared to baseline values. The inhibitory effect of the appliances was specific to the number of phasic EMG episodes and bursts (P < 0·01), with no effects on tonic EMG bursts or episodes (P > 0·30). The results indicated that restriction of mandibular movements with oral appliances do not have any major influence on jaw-muscle activity during sleep but rather that the immediate effect of any combination of oral appliances lead to a suppression of phasic EMG bursts and episodes.

Sandwich enzyme immunoassay of tumor-associated antigen sialosylated Lewisx using beta-D-galactosidase coupled to a monoclonal antibody of IgM isotype.

Enzyme conjugates with antibody of IgG type have been used extensively in immunohistochemistry, but conjugates with antibody of IgM type have not been reported. This paper describes the beta-D-galactosidase (Gal) labeling of a monoclonal IgM antibody designated CSLEX1 (for cytotoxic sialosylated Lewisx), which is directed against a tumor-associated antigen sialosylated Lewisx (S-Lex). The antibody was first acylated with a heterobifunctional agent N-(gamma-maleimidobutyryloxy)succinimide (GMBS) to introduce the maleimide groups into the molecule; excess reagent was removed by gel filtration and then the activated antibodies were crosslinked to the thiol groups of Gal. The conjugates were partially purified of free Gal by DEAE-Toyopearl column chromatography with an increasing linear concentration of NaCl. The conjugates thus prepared retained almost full enzyme activity and were demonstrated to be free of CSLEX1 by affinity chromatography using anti-galactosidase antibody bound to Sepharose 4B. The conjugates were used as a label in a sandwich enzyme immunoassay (SEIA) to detect the antigen at concentrations as low as 0.2 U/well. The SEIA was used to measure serum S-Lex levels in both healthy subjects and lung cancer patients and mean concentrations of 70 U/ml and 198.6 U/ml were detected respectively.

Intrinsic healing capacity and tearing process of torn supraspinatus tendons: in situ hybridization study of alpha 1 (I) procollagen mRNA.

To determine the healing potential and healing process of torn supraspinatus tendons, in situ hybridization was used to localize cells containing alpha 1 type-I procollagen mRNA. Biopsy specimens of torn supraspinatus tendons from 19 patients with complete-thickness tears and 13 patients with incomplete-thickness tears were obtained during surgery. Four macroscopically normal supraspinatus tendons were obtained to serve as normal controls. Specimens were fixed in 10% buffered formalin and embedded in paraffin. A 22-mer oligonucleotide probe was labeled with digoxigenin and used as an in situ marker. The labeled cells were mainly composed of tenocytes and undifferentiated mesenchymal cells. In complete-thickness-tears, the labeled cells at the proximal tendon-stumps in the specimens that were obtained less than 4 months after trauma were significantly more abundant than in the specimens obtained 4 months or more after trauma. However, the number of labeled cells was maintained at the torn portion even in long-standing incomplete-thickness tears. The labeled cells at the margins of concomitant intratendinous extensions of the tears were detected even in the long-standing tears. The intratendinous extensions exhibited more labeled cells than the bursal-side or joint-side layers of the tendon substance in the incomplete-thickness tears (p < 0.05). The torn supraspinatus tendon may possess an intrinsic healing capability in the intermediate and late phases of tendon healing. Incomplete-thickness tears and concomitant intratendinous extensions can continue to rupture after the initial injury.

Significance of granulation tissue in torn supraspinatus insertions: an immunohistochemical study with antibodies against interleukin-1 beta, cathepsin D, and matrix metalloprotease-1.

The pathophysiology of rotator cuff tears can be elucidated by examining the tendinous insertion of the supraspinatus muscle. As seen by light microscopy, the granulation tissue around the insertion of a torn supraspinatus tendon appears to induce osteochondral destruction by means of multinucleated giant cells and chemical mediators. The purpose of this study was to examine the contribution of certain chemical mediators to osteochondral destruction using immunohistochemical analysis of interleukin-beta, cathepsin D, and matrix metalloprotease-1. Sixteen supraspinatus insertions with portions of the greater tuberosity, including eight complete-thickness tears and eight incomplete-thickness tears, were obtained during surgery. Six fresh cadaveric supraspinatus tendons without grossly evident tears served as normal controls. Strong immunoreactivity was found in all 16 torn supraspinatus insertions but not in the six insertions of apparently intact tendons. Macrophages and multinucleated giant cells, which showed immunoreactivity for all three chemical mediators, were often found at the interface between the osteochondral margin of the enthesis and the granulation tissue, suggesting that they may be involved in osteochondral destruction. We therefore concluded that, in addition to repetitive subacromial impingement, this granulation tissue may contribute to the development of rotator cuff tears by weakening the insertion.

[The concomitant effect of a newly developed gamma-globulin preparation (SM-4300) with some antibiotics on severe bacterial infections].

Twenty-six patients with bacterial infections, mainly respiratory infections, were treated with newly developed gamma-globulin preparation (SM-4300), as a combination therapy with some antibiotics. The result was as follows. Clinical effects of 18 cases evaluated were excellent in 1 case (5.6%), good in 10 (55.6%), fair in 4 (22.2%) and poor in 3 (16.7%). No remarkable adverse reactions and abnormal value in laboratory data due to administration of SM-4300 were observed. Significant changes of complement system before and after administration of SM-4300 were not observed. It was considered that SM-4300 was effective as a combination therapy with some antibiotics for the treatment of severe or refractory bacterial infections.

Expression of procollagen alpha 1 type III mRNA in rotator cuff tears.

The purpose of this study was to investigate the relationship among expression of procollagen alpha 1 type III mRNA, subacromial adhesion, and limited shoulder elevation in rotator cuff tears. Procollagen alpha 1 type III mRNA was analyzed in the torn supraspinatus tendons and synovial tissue of 42 patients with rotator cuff tears. As a control, four normal supraspinatus tendons of patients who had undergone shoulder surgery other than rotator cuff repair served as controls. Cells stained positively for procollagen alpha 1 type III mRNA were more abundant in the adhesive synovium of the subacromial bursa and in the torn supraspinatus tendons than in controls. Patients with complete-thickness tears who had undergone surgery less than 10 months after trauma were found to have more signal-positive cells than those later than 10 months. We conclude that the adhesive synovium of the subacromial bursa contains abundant cells stained positively for procollagen alpha 1 type III mRNA. We suggest that the production of type III collagen by these cells could contribute to the limitation of shoulder motion in patients with rotator cuff tears, and recommend release and excision of the excess adhesive synovium during rotator cuff surgery.

Craniofacial pain and jaw-muscle activity during sleep.

This study compared the jaw-muscle electromyographic (EMG) activity during sleep in patients with craniofacial pain (n = 63) or no painful conditions (n = 52) and between patients with tension-type headache (TTH: n = 30) and healthy control individuals (n = 30). All participants used a portable single-channel EMG device (Medotech A/S) for four nights. There was no significant difference in EMG activity between craniofacial pain (24.5 ± 17.9 events/hr) and no painful conditions (19.7 ± 14.5), or between TTH (20.8 ± 15.0) and healthy control individuals (15.2 ± 11.6, p >.050). There were positive correlations between EMG activity and number of painful muscles (r = 0.188; p = 0.044), characteristic pain intensity (r = 0.187; p = 0.046), McGill Pain Questionnaire (r = 0.251; p = 0.008), and depression scores (r = 0.291; p = 0.002). Patients with painful conditions had significantly higher night-to-night variability compared with pain-free individuals (p < 0.050). This short-term observational study suggests that there are no major differences between patients with different craniofacial pain conditions and pain-free individuals in terms of jaw-muscle EMG activity recorded with a single-channel EMG device during sleep. However, some associations may exist between the level of EMG activity and various parameters of craniofacial pain. Longitudinal studies are warranted to further explore the relationship between sleep bruxism and craniofacial pain.