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.

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.

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.

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.

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.

Partial-thickness tears of the rotator cuff. A clinicopathological review based on 66 surgically verified cases.

This review is based on 66 patients with partial-thickness tears of the rotator cuff, verified at operation. Their average age was 54 years, and all had symptoms of subacromial impingement. The duration of shoulder pain was for between 2 and 108 months (mean 11.4 months). Ultrasonography, arthrography and bursography were helpful in establishing the diagnosis. On exploration, tears were found in the supraspinatus tendon, with 9 extending into the infraspinatus. After anterior acromioplasty, excision of the diseased portion and tenorrhaphy were undertaken. Satisfactory results were obtained in 62 patients (94%) with an average follow-up of 32 months. Spontaneous repair at the torn site was never seen. In addition to Neer's staging of impingement, we propose a new classification based on the integrity of the cuff tendon. We conclude that a partial-thickness cuff tear is an important cause of shoulder disability, which deserves much more clinical attention; misdiagnosis is common and leads to mismanagement. When conservative treatment fails, accurate diagnosis and proper surgical repair are essential.

The detection of the mRNAs of procollagen types I, II and III in human fetal fingers by in situ hybridization using digoxigenin-labelled oligonucleotide probes.

Messenger RNAs (mRNAs) encoding procollagen alpha 1 type I,alpha 1 type II and alpha 1 type III have been localized in paraffin sections of human fetal fingers using digoxigenin-labelled synthetic oligonucleotide probes. The probe-mRNA hybrids were visualized using an anti-digoxin antibody amplified with sandwich techniques. These protocols provided an excellent hybridization signal with minimal background noise. The sensitivity of the protocols was nearly equivalent to that seen when using isotopic cDNA probes. In human fetal fingers, intense hybridization signals for procollagen alpha 1 type I mRNA were detected in the osteoblasts and the fibroblasts of periosteum and perichondrium, the tenocytes of tendons, fibroblasts of ligaments, the synovial membrane and deeper layers of the dermis. In contrast, positive hybridization signals for procollagen alpha 1 type II mRNA were visualized in chondrocytes and the cambial layer of perichondrium. The signals for procollagen alpha 1 type III mRNA were detected in the fibroblasts of the dermis and perichondrium. The probes which have lower melting temperatures (Tm) could not detect the corresponding mRNAs.

Localization of mRNA of procollagen alpha 1 type I in torn supraspinatus tendons. In situ hybridization using digoxigenin labeled oligonucleotide probe.

A tendon is predominantly composed of collagen Type I. To determine the synthesis of collagen Type I after a rotator cuff tear, an in situ hybridization technique was applied to localize cells containing procollagen alpha 1 Type I in the proximal stump of five torn supraspinatus tendons obtained during surgery. Specimens were fixed in 10% buffered formalin, embedded in paraffin, and sectioned at 6 microns. A 22 mer oligonucleotide corresponding to a sequence coding a part of human procollagen alpha 1 Type I messenger RNA (mRNA) was used as a hybridization probe. The probe was 3'-end labeled with digoxigenin-11-dUTP, and the probe-mRNA hybrids were enzymatically visualized using conventional chromogens for alkaline phosphatase. The procollagen alpha 1 type I mRNA was clearly observed in the cells near the margin of the tear. However, they were not consistently found in the vicinity of the intratendinous extension of the tear and in cells of the subacromial bursa. It is concluded that this method should be used to study the characteristics of collagen synthesis in a torn rotator cuff tendon.

Pathology and pathogenesis of the intratendinous tearing of the rotator cuff viewed from en bloc histologic sections.

Histologic sections from 17 en bloc surgical specimens were studied to clarify the pathogenesis of intratendinous tears of the rotator cuff. The specimens consisted of the bony insertion, the partially torn area, and the musculotendinous junction of the supraspinatus tendon. An intratendinous tear alone was present in two patients, and was associated with bursal side cuff tears in seven patients and joint side cuff tears in eight. There were 13 men and 4 women, whose average age was 49.8 years. Trauma was noted in all intratendinous tears and combined intratendinous and joint side cuff tears and in two of the seven patients who had intratendinous plus bursal side tears. All patients exhibited clinical evidence of subacromial impingement. Histologic sections were stained with azan and hematoxylin and eosin. Microscopically, the sections demonstrated several abnormalities in addition to degeneration. The intratendinous tears was located in the midlayer of the tendon in 15 specimens and eccentrically in two, the axis of which were parallel to tendon fibers in all. The intratendinous tears continued to local disruptions of the enthesis in 11 cases. The inner surface of the tear appeared smooth in 16 specimens. Despite the presence of granulation tissue and vessel proliferation near the intratendinous tears, there was no evidence of closure of the defect in any specimen. Intratendinous tears develop between superficial and deep layers of the degenerated rotator cuff. Shear within the tendon appears to be responsible in pathogenesis. Concomitant subacromial bursitis is very common.

Molecular characterization of genetic mutations in human lactate dehydrogenase (LDH) B (H) variant.

We have previously detected a single base substitution of G by A at the Arg codon CGC in exon 4 of the mutant lactate dehydrogenase (LDH) gene, an unstable LDH-B variant (case 1). Here, we use the polymerase chain reaction (PCR) to amplify genomic DNA of two cases (the original case 1 and a new patient, case 2). We were able to confirm that case 1 is homozygous for the mutation, causing a replacement of the conserved Arg by His at residue 173. The resulting LDH-B variant subunit is unstable in vivo. Whereas the mutation in exon 4 was not observed in case 2, a different single base substitution of A by C was detected at the Ser codon AGT in exon 3. This mutation causes a replacement of the conserved Ser by Arg at residue 131. Genomic analysis of the family of case 2 by mismatched PCR showed that the missense mutation was consistent with their biochemical phenotypes. The replacement results in a conformational change of the residues near the Ser, probably because the side chain of Arg is much more bulky than that of Ser. The change may affect the arrangement of the cofactor binding site and result in the loss of enzyme activity. The experimental observations are consistent with computer graphics analyses.

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.

[Immunohistological observation of blood group-related antigens in lung adenocarcinomas using monoclonal antibodies].

The immunohistological distribution of blood group (BG)-related antigens including A, B, H type 2, and sialylated Lex in lung adenocarcinomas was examined using monoclonal antibodies. BG-A, B, and H type 2 compatible with the ABO status in tumor cells were expressed in 60% of the cases. Accumulation of H type 2, associated with loss of BG-A and B, was observed in tumor cells of patients with BG status other than 0. Tumor-associated antigens, Lex and sialylated Lex were detected in 36.0% and 72.0%, respectively. Modification of carbohydrate antigens in cancer may be associated with incomplete synthesis; accumulation of precursor antigen; and activated sialylation.

[Sialylated Lewis x as a tumor-associated antigen in stomach cancer].

Sialylated Lewis (S-Lex) has been studied histologically and serologically in stomach cancer by the CSLEX1 monoclonal antibody. S-Lex was expressed in 73.9% of 46 stomach cancer tissues, 29.4% of metaplastic parts adjacent to cancer, and none of six gastric ulcer tissues including metaplasia. Serologically positive percentages were as follows: 26.0% of 100 stomach cancers, 0.9% of 322 benign diseases, and 0.7% of 280 healthy donors in the sera, as well as 72.4% of 29 ascites of stomach cancers and 5.3% of 17 effusions of benign diseases. These findings demonstrate that S-Lex possesses a potential usefulness as a tumor marker in stomach cancer.