Reliability and validity of Axis I of the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) with proposed revisions.

The research diagnostic criteria for temporomandibular disorders (RDC/TMD) have been employed internationally since 1992 for the study of temporomandibular muscle and joint disorders (TMD). This diagnostic protocol incorporates a dual system for assessment of TMD for Axis I physical diagnoses as well as Axis II psychological status and pain-related disability. Because the reliability and criterion validity of RDC/TMD had not yet been comprehensively characterised, the National Institute of Dental and Craniofacial Research funded in 2001 the most definitive research to date on the RDC/TMD as a U01 project entitled, 'Research Diagnostic Criteria: Reliability and Validity'. The results of this multi-site collaboration involving the University of Minnesota, the University of Washington, and the University at Buffalo were first reported at a pre-session workshop of the Toronto general session of the International Association of Dental Research on 2 July 2008. Summaries of five reports from this meeting are presented in this paper including: (i) reliability of RDC/TMD Axis I diagnoses based on clinical signs and symptoms; (ii) reliability of radiographic interpretations used for RDC/TMD Axis I diagnoses; (iii) reliability of self-report data used for RDC/TMD Axis I diagnoses; (iv) validity of RDC/TMD Axis I diagnoses based on clinical signs and symptoms; and (v) proposed revisions of the RDC/TMD Axis I diagnostic algorithms.

Comparative characterization of the 21-kD and 26-kD gap junction proteins in murine liver and cultured hepatocytes.

Affinity-purified antibodies to mouse liver 26- and 21-kD gap junction proteins have been used to characterize gap junctions in liver and cultured hepatocytes. Both proteins are colocalized in the same gap junction plaques as shown by double immunofluorescence and immunoelectron microscopy. In the lobules of rat liver, the 21-kD immunoreactivity is detected as a gradient of fluorescent spots on apposing plasma membranes, the maximum being in the periportal zone and a faint reaction in the perivenous zone. In contrast, the 26-kD immunoreactivity is evenly distributed in fluorescent spots on apposing plasma membranes throughout the rat liver lobule. Immunoreactive sites with anti-21 kD shown by immunofluorescence are also present in exocrine pancreas, proximal tubules of the kidney, and the epithelium of small intestine. The 21-kD immunoreactivity was not found in thin sections of myocardium and adult brain cortex. Subsequent to partial rat hepatectomy, both the 26- and 21-kD proteins first decrease and after approximately 2 d increase again. By comparison of the 26- and 21-kD immunoreactivity in cultured embryonic mouse hepatocytes, we found (a) the same pattern of immunoreactivity on apposing plasma membranes and colocalization within the same plaque, (b) a similar decrease after 1 d and subsequent increase after 3 d of both proteins, (c) cAMP-dependent in vitro phosphorylation of the 26-kD but not of the 21-kD protein, and (d) complete inhibition of intercellular transfer of Lucifer Yellow in all hepatocytes microinjected with anti-26 kD and, in most cases, partial inhibition of dye transfer after injection of anti-21 kD. Our results indicate that both the 26-kD and the 21-kD proteins are functional gap junction proteins.

Randomized effectiveness study of four therapeutic strategies for TMJ closed lock.

For individuals with temporomandibular joint (TMJ) disc displacement without reduction with limited mouth opening (closed lock), interventions vary from minimal treatment to surgery. In a single-blind trial, 106 individuals with TMJ closed lock were randomized among medical management, rehabilitation, arthroscopic surgery with post-operative rehabilitation, or arthroplasty with post-operative rehabilitation. Evaluations at baseline, 3, 6, 12, 18, 24, and 60 months used the Craniomandibular Index (CMI) and Symptom Severity Index (SSI) for jaw function and TMJ pain respectively. Using an intention-to-treat analysis, we observed no between-group difference at any follow-up for CMI (p > or = 0.33) or SSI (p > or = 0.08). Both outcomes showed within-group improvement (p < 0.0001) for all groups. The findings of this study suggest that primary treatment for individuals with TMJ closed lock should consist of medical management or rehabilitation. The use of this approach will avoid unnecessary surgical procedures.

Longitudinal Stability of Common TMJ Structural Disorders.

The longitudinal course of temporomandibular joint (TMJ) disc displacement (DD) and degenerative joint disease (DJD) has never been conclusively described with magnetic resonance imaging and computed tomography, respectively. This 8-y observational study's objective was to assess the longitudinal stability of DD and DJD among 401 subjects. The Validation Project provided baseline measures; follow-up was performed in the TMJ Impact Project. With magnetic resonance imaging, 2 radiologists rendered a consensus diagnosis of normal/indeterminate, DD with reduction, or DD without reduction. Computed tomography consensus diagnoses included normal/indeterminate, grade 1 DJD, or grade 2 DJD. Radiologist reliability was assessed by kappa; a Hui-Walter model was used to estimate, after accounting for diagnostic disagreement, the frequency of diagnostic progression and reversal. Permutation tests were used to test the statistical influence of concurrent baseline diagnoses on diagnostic changes at follow-up. Of 789 baseline joint-specific soft tissue diagnoses of DD, 598 (76%) joints showed no change; 109 (14%) demonstrated progression; and 82 (10%) had reversal. Of 794 joints with baseline joint-specific hard tissue diagnoses of DJD, progression was observed in 122 (15%) joints, no change in 564 (71%), and reversal in 108 (14%). Radiologist reliability (kappa) was 0.73 (95% CI, 0.64 to 0.83) for DD and 0.76 (95% CI, 0.68 to 0.83) for DJD. After accounting for the influence of diagnostic disagreement, progression of hard tissue diagnoses in the right TMJ occurred in 15.2% of subjects (95% CI, 10.5% to 20.8%) and reversal in 8.3% (95% CI, 4.9% to 12.3%); results were similar for soft tissue diagnoses and the left TMJ. Concurrent baseline soft tissue diagnoses were associated with hard tissue diagnostic changes at follow-up ( P < 0.0001). Baseline hard tissue diagnoses showed no statistical association with soft tissue changes at follow-up ( P = 0.11). Longitudinally, 76% of baseline TMJ soft tissue diagnoses and 71% of the baseline hard tissue diagnoses remained stable. Diagnostic reversal and progression were confirmed for both soft and hard tissues.

Cyclic adenosine monophosphate stimulates biosynthesis and phosphorylation of the 26 kDa gap junction protein in cultured mouse hepatocytes.

Hepatocytes prepared from 18-day-old mouse embryos were grown in serum-free medium and reached confluence after two days in culture. The total amount of the 26 kDa gap junction protein decreased in these cells during the first 24 h in culture and increased again between day 1 and day 3 more than 10-fold. At day 3 a half-life time of 2.5 to 3 h was determined for the 26 kDa protein by [35S]methionine incorporation and immunoprecipitation using affinity-purified anti-26 kDa. Incorporation of [32P]orthophosphate into the 26 kDa protein of cultured hepatocytes was found at serine residues (98%) and tyrosine residues (about 2%). The addition of dibutyryl cyclic adenosine monophosphate (db cAMP) to the culture medium at day 2 had two effects: After 15 min the extent of phosphorylation of the 26 kDa protein increased 2.7-fold whereas the total amount of the 26 kDa protein increased only 1.2-fold. After 3 h of incubation with db cAMP, a 2.5-fold increase of the 26 kDa protein was noticed which was accompanied by a 3.2-fold increase in phosphorylation of serine residues. The effects of db cAMP on phosphorylation of the 26 kDa protein could be augmented or mimicked by the addition of isoproterenol, theophylline or forskolin to the culture medium of hepatocytes. In extracts of rat hepatocarcinoma MH1C1 cells and dog kidney MDCK cells, a phosphorylated 26 kDa protein can be immunoprecipitated using anti-liver 26 kDa. These results demonstrate that the gap junction 26 kDa protein can be posttranslationally modified by cAMP-dependent phosphorylation.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of four treatment strategies for temporomandibular joint closed lock.

A previous randomized controlled trial (RCT) by Schiffman et al. (2007)(15) compared four treatments strategies for temporomandibular joint (TMJ) disc displacement without reduction with limited mouth opening (closed lock). In this parallel group RCT, 106 patients with magnetic resonance imaging (MRI)-confirmed TMJ closed lock were randomized between medical management, non-surgical rehabilitation, arthroscopic surgery, and arthroplasty. Surgical groups also received rehabilitation post-surgically. The current paper reassesses the effectiveness of these four treatment strategies using outcome measures recommended by the International Association of Oral and Maxillofacial Surgeons (IAOMS). Clinical assessments at baseline and at follow-up (3, 6, 12, 18, 24, and 60 months) included intensity and frequency of TMJ pain, mandibular range of motion, TMJ sounds, and impairment of chewing. TMJ MRIs were performed at baseline and 24 months, and TMJ tomograms at baseline, 24 and 60 months. Most IAOMS recommended outcome measures improved significantly over time (P≤0.0003). There was no difference between treatment strategies relative to any treatment outcome at any follow-up (P≥0.16). Patient self-assessment of treatment success correlated with their ability to eat, with pain-free opening ≥35mm, and with reduced pain intensity. Given no difference between treatment strategies, non-surgical treatment should be employed for TMJ closed lock before considering surgery.

Effects of undernutrition in neonatal rats on physical development and food and water regulation.

The effects of neonatal undernutrition in rats on food and water regulation, external indices of development, and long-term regulatory behavior were investigated. Undernutrition produced retardation in some external indices of development. The ability to eat, drink, and maintain body weight at weaning were not seriously affected by the undernutrition. Longer term deficiencies in feeding efficiency, osmotic regulation, prandial drinking, and activity were found for experimental subjects. The involvement of peripheral-systemic factors as well as neurological retardation in producing feeding and drinking deficits following undernutrition are discussed.

Current prosthodontic practice: a dental laboratory survey.

A survey was distributed to dental laboratory owners at the 1988 annual meeting of the Minnesota Dental Laboratory Association. Current laboratory practice in infection control, the use of nonprecious alloys, the amount of time devoted to complete removable prosthodontics, and complete denture laboratory techniques were surveyed. Responses indicate a moderate level of awareness and compliance with infection control techniques recommended by the American Dental Association, a declining demand for removable prosthodontic services, a high percentage of use of nonprecious alloys, and a very high rate of porcelain occlusion requested by dental practitioners. Comparisons with other laboratory surveys and the implications of these results for undergraduate education in prosthodontics are discussed.

Marked resistance of RAR gamma-deficient mice to the toxic effects of retinoic acid.

Excessive intake of retinol or of retinoic acid causes a syndrome of characteristic toxic effects known as hypervitaminosis A. To test the role of the nuclear retinoic acid receptor (RAR gamma) in this process we produced mice with a targeted disruption of the RAR gamma gene and examined toxic effects of repeated doses of retinoic acid and two other synthetic retinoids, Ro 15-1570 and Ro 40-6055. Surprisingly, homozygous mutant mice were resistant to fourfold higher doses of retinoic acid than wild-type mice as well as to elevated doses of the synthetic retinoids, indicating that RAR gamma may have a major role in mediating retinoid toxicity, a finding that possibly has practical implications for reducing the toxicity of synthetic retinoids in clinical use.

Preliminary results from disinfection of irreversible hydrocolloid impressions.

The virucidal efficacy of germicides acting on an irreversible hydrocolloid surface is not known. Tests that are currently performed on germicides do not simulate the conditions under which the germicides are often used. One major concern for the dental profession is the disinfection of dental impressions, particularly irreversible hydrocolloid impressions. This study was designed to test the biocidal action of germicides against an enveloped virus on an irreversible hydrocolloid surface. The disinfection model, which was developed to simulate clinical conditions, specified the use of vesicular stomatitus virus, an animal virus amenable to safe handling. A 0.5% sodium hypochlorite spray inactivated the virus when the spray was allowed to remain on the impression 3 to 10 minutes. The iodophor disinfectant required a 3- to 10-minute immersion for total inactivation. Although 2% glutaraldehyde achieved total viral inactivation in less than 1 minute, the authors conclude that short disinfectant sprays, in general, are not an appropriate disinfection method.

The hepatocyte-specific phenotype of murine liver cells correlates with high expression of connexin32 and connexin26 but very low expression of connexin43.

This investigation was initiated in order to find out whether expression of the hepatocyte-specific phenotype is accompanied by expression of certain connexin genes coding for gap junctional protein subunits. Several clones of mouse embryonic hepatocytes immortalized in serum-free MX83 medium by infection with recombinant retrovirus-expressed transcripts for connexin32, connexin26, albumin, alpha-fetoprotein, tyrosine aminotransferase, as well as aldolase A and B, at more than half of the levels found in primary mouse hepatocytes. In addition the immortalized hepatocyte clones contained low levels of connexin43 mRNA of which only trace amounts were detected in primary embryonic mouse hepatocytes and in rat liver. Two of the immortalized hepatocyte clones were shifted from serum-free MX83 medium to Dulbecco's modified Eagle medium (DMEM) containing 10% fetal calf serum and, after 2, 14, or 180 days, back to MX83 medium. We found that expression of connexin32 and connexin26 mRNAs as well as transcripts of other liver-specific proteins was reversibly decreased in serum-containing medium, whereas the expression level of connexin43 transcripts was increased in serum-containing DMEM compared to serum-free MX83 medium. The expression levels of connexin26, connexin32, or connexin43 mRNAs were altered by the addition of fetal calf serum or arginine or by the absence of hydrocortisone in MX83 medium, all of which contributed to the shift in phenotype. Furthermore several dedifferentiated cell lines derived from rat or mouse liver and cultivated in serum-containing medium were found to express little connexin32 or connexin26 mRNA but relatively high levels of connexin43 mRNA.