[A case of congenital mesoblastic nephroma in adulthood]

A 20-year-old man was referred to our hospital with a complaint of asymptomatic macrohematuria. A diagnosis of a right renal tumor was made after several radiographic examinations and right radical nephrectomy was performed. Histopathologically the tumor was a congenital mesoblastic nephroma. Congenital mesoblastic nephroma is a relatively rare renal tumor predominantly of childhood. Occurrence in adults is exceedingly rare and 18 cases have been reported to date.

The validity of clinical examination for diagnosing anterior disk displacement without reduction

OBJECTIVE

The objective of this study was to evaluate the diagnostic accuracy of patient history and clinical signs as confirmed by magnetic resonance imaging examination for diagnosing anterior disk displacement without reduction.

STUDY DESIGN

A series of 273 consecutive patients with temporomandibular disorders were clinically examined according to well-defined criteria. Patients were first asked if they had a history of clicking. The following clinical characteristics of anterior disk displacement without reduction were then assessed: (1) maximal mouth opening less than 40 mm; (2) deflection of the mandible to the affected side at the maximal mouth opening position; (3) limitation of condylar translation on palpation during maximal mouth opening; (4) preauricular pain during mandibular movements; and (5) crepitation. Bilateral magnetic resonance images were obtained for all patients, and the magnetic resonance imaging interpretation was compared with the clinical examination findings to assess the diagnostic accuracy of the clinical findings.

RESULTS

The sensitivity was considerably low in contrast with the relatively high specificity for all six clinical parameters tested. The overall accuracies of the clinical parameters ranged from 71% to 81%.

CONCLUSION

Our results suggest that the predictability of historical or clinical findings to differentiate anterior disk displacement without reduction from other diagnoses is not high.

Natural co-occurrence of aflatoxins and Fusarium mycotoxins (fumonisins, deoxynivalenol, nivalenol and zearalenone) in corn from Indonesia

Sixteen corn samples collected from Indonesia were analysed for aflatoxins (AF), fumonisins (FM), trichothecenes and zearalenone (ZEA) using high-performance liquid chromatography and gas chromatography-mass spectrometry. AF were detected in 11 (69%) samples at a mean level of 119 ng/g (maximum 487 ng/g) and FM in all of the samples at a mean level of 895 ng/g (maximum 2970 ng/g). Deoxynivalenol (DON), nivalenol (NIV) and ZEA were each detected in two (12%) samples; 21 and 32 ng/g, 49 and 169 ng/g, and 11 and 12 ng/g, respectively. All of the AF-contaminated samples were co-contaminated with FM. Mycological study showed all of the AF-contaminated samples were infected with A. flavus/A. parasiticus, and the FM-contaminated samples were either infected with F. moniliforme (50%), F. proliferatum (12%), F. nygamai (6%) or F. decemcellulare (38%). Supportive mycological studies showed that Fusarium species isolated from Indonesian corn were capable of producing a mean level of 10,000 micrograms/g FM. Based on these results, the correlation between FM-producers and AF-producers on kernel infection and contamination of these mycotoxins in corn was discussed. This is the first report on the natural co-occurrence of AF and various Fusarium mycotoxins, including DON and NIV in corn from Indonesia, and also the first report on the natural occurrence of DON in corn from hot areas of Southeast Asia.

Improvement in the tensile bond strength between resin cement and dentin surfaces after temporary cement application

PURPOSE

The aim of this study was to evaluate the efficacy of three tooth conditioners in restoring the reduced bond strength between resin cement and teeth resulting from remaining temporary cement.

MATERIALS AND METHODS

Ethyl dihydrogen phosphate, methacryloxyethyl dihydrogen phosphate, and 2-methacryloxyethyl hydrogen maleate were evaluated as conditioners. After eliminating the temporary cement with a curette from the bovine dentin surface, the conditioners were applied onto the surface of the specimen and a resin cement was adhered. Stepwise scanning electron microscopic observation and tensile bond strength measurement were carried out.

RESULTS

Granular substances were present on the dentin surface even when the temporary cement was carefully eliminated with a curette. When primer and resin cement were applied on this surface without conditioner application, no resin tag or hybrid layer was observed and the mean bonding strength between tooth and adhesive resin cement was 1.8 MPa. In contrast, resin tag and hybrid layer were observed after primer and resin cement application when the dentinal surface was treated with conditioner. Mean tensile bone strength values increased to 6.2 MPa for specimens treated with 20% methacryloxyethyl dihydrogen phosphate for 60 seconds.

CONCLUSION

The authors recommend methacryloxyethyl dihydrogen phosphate as it provides high tensile bond strength values and requires no additional rinse step.

Crystal structures of two tropinone reductases: different reaction stereospecificities in the same protein fold

A pair of tropinone reductases (TRs) share 64% of the same amino acid residues and belong to the short-chain dehydrogenase/reductase family. In the synthesis of tropane alkaloids in several medicinal plants, the TRs reduce a carbonyl group of an alkaloid intermediate, tropinone, to hydroxy groups with different diastereomeric configurations. To clarify the structural basis for their different reaction stereospecificities, we determined the crystal structures of the two enzymes at 2.4- and 2.3-A resolutions. The overall folding of the two enzymes was almost identical. The conservation was not confined within the core domains that are conserved within the protein family but extended outside the core domain where each family member has its characteristic structure. The binding sites for the cofactor and the positions of the active site residues were well conserved between the two TRs. The substrate binding site was composed mostly of hydrophobic amino acids in both TRs, but the presence of different charged residues conferred different electrostatic environments on the two enzymes. A modeling study indicated that these charged residues play a major role in controlling the binding orientation of tropinone within the substrate binding site, thereby determining the stereospecificity of the reaction product. The results obtained herein raise the possibility that in certain cases different stereospecificities can be acquired in enzymes by changing a few amino acid residues within substrate binding sites.

Crystal structures of two tropinone reductases: different reaction stereospecificities in the same protein fold

A pair of tropinone reductases (TRs) share 64% of the same amino acid residues and belong to the short-chain dehydrogenase/reductase family. In the synthesis of tropane alkaloids in several medicinal plants, the TRs reduce a carbonyl group of an alkaloid intermediate, tropinone, to hydroxy groups with different diastereomeric configurations. To clarify the structural basis for their different reaction stereospecificities, we determined the crystal structures of the two enzymes at 2.4- and 2.3-A resolutions. The overall folding of the two enzymes was almost identical. The conservation was not confined within the core domains that are conserved within the protein family but extended outside the core domain where each family member has its characteristic structure. The binding sites for the cofactor and the positions of the active site residues were well conserved between the two TRs. The substrate binding site was composed mostly of hydrophobic amino acids in both TRs, but the presence of different charged residues conferred different electrostatic environments on the two enzymes. A modeling study indicated that these charged residues play a major role in controlling the binding orientation of tropinone within the substrate binding site, thereby determining the stereospecificity of the reaction product. The results obtained herein raise the possibility that in certain cases different stereospecificities can be acquired in enzymes by changing a few amino acid residues within substrate binding sites.

Differential activation of two JNK activators, MKK7 and SEK1, by MKN28-derived nonreceptor serine/threonine kinase/mixed lineage kinase 2

MKN28-derived nonreceptor type of serine/threonine kinase/mixed lineage kinase 2 (MST/MLK2) directly phosphorylates and activates SEK1/MKK4/JNKK1/SKK1 in vitro, thereby acting as a mitogen-activated protein (MAP) kinase kinase kinase in the JNK/SAPK pathway (Hirai, S. -i., Katoh, M., Terada, M., Kyriakis, J. M., Zon, L. I., Rana, A., Avruch, J., and Ohno, S. (1997) J. Biol. Chem. 272, 15167-15173). The in vitro reconstitution system for the kinase cascade allowed us now to identify JNK/SAPK activators involved in the MST/MLK2-dependent activation of JNK/SAPK in vivo. We show that at least two distinct MST/MLK2-dependent JNK/SAPK activators are present in the fractionated COS-1 cell lysate, and that they appear to be SEK1/MKK4/JNKK1/SKK1 and MKK7/JNKK2/SKK4 by Western blot analysis. Notably, a majority of the MST/MLK2-dependent JNK/SAPK-activating activity is found in MKK7-containing fractions, whereas the MEKK1-dependent activity is comparably distributed in SEK1- and MKK7-containing fractions. Moreover, MST/MLK2 activates recombinant MKK7 more effectively than recombinant SEK1, whereas MEKK1 activates both to a similar extent. In addition, the deletion analysis on MST/MLK2 showed that the kinase domain is responsible for the determination of substrate specificity. These results provide a molecular aspect to the differential regulation of the two JNK activators by a variety of cellular stimuli.

cDNA cloning of a novel rainbow trout SRY-type HMG box protein, rtSox23, and its functional analysis

We have isolated a cDNA clone for a new member of Sox genes, termed rtSox23, from a rainbow trout ovary cDNA library. rtSox23 mRNA was notably expressed in ovary and brain. rtSox23 contains a leucine zipper in addition to an SRY-type HMG box. Although the recombinant HMG box region protein of rtSox23 could bind to an AACAAT sequence, the full-length rtSox23 could form a homodimer and did not bind to the sequence. Furthermore, using a two-hybrid system, we have isolated a cDNA clone encoding a protein that bound to the leucine zipper region of rtSox23. This protein was the rainbow trout homologue of mouse nucleoporin p62, which is a component of the nuclear pore complex in nuclear envelope. The rainbow trout p62 mRNA was also prominent in ovary and brain. Taken together, these results suggest that the rainbow trout p62 associates with rtSox23 in vivo and modulates the function of rtSox23.

Thoracoscopic radiofrequency ablation of the myocardium

Radiofrequency (RF) catheter ablation has been used for the treatment of ventricular tachycardia (VT), however, in some patients VT might result from subepicardial macroreentry that could be successfully terminated by epicardial approach. This study examined the feasibility of thoracoscopic RF ablation of myocardium from epicardium using a custom made electrode. In five mongrel dogs, the thoracoscope was introduced through the 7th intercostal space. A 500-KHz continuous wave RF energy was connected to a custom made multiple electrode probe. Under thoracoscopic guidance, the heart was exposed and the RF probe was introduced. RF ablation was performed on the nonvascular ventricular wall of the beating heart. The left ventricular free wall and right ventricular outflow tract were satisfactorily visualized and ablated. The total dose of RF energy ranged from 50 to 500 J, and the estimated volume of ablated lesions ranged from 41.0-799 mm3. There were significant correlations between the RF discharge output and the irradiated lesion volume (P < 0.01), and the depth of the lesions (P < 0.01). Grossly, after RF ablation the ventricular myocardium demonstrated a circular, well-demarcated area of thermal injury. Volume and depth of the lesion depended upon the total dose of delivered RF energy. Thoracoscopic RF ablation appears to be a minimally invasive and useful method for creating irradiated myocardial lesions from epicardial surface. This method could be technically feasible for the treatment of Vts for which endocardial RF ablation is ineffective.

Ontogeny of GABA-immunoreactive cells in the prefrontal and occipital cortices of the primate

The developmental changes in the density of total neurons and GABA-immunoreactive cells were examined in the prefrontal and occipital cortices of the crab-eating monkey, Macaca fascicularis. The density of total neurons declined rapidly during the embryonic period. Both density and proportion of GABA cells increased rapidly during the embryonic period, and only gradually increased between birth and postnatal day 30. Both density and proportion of GABA cells were higher in the occipital cortex than the prefrontal cortex between embryonic day 110 and 140, indicating late development of the prefrontal area. The activity of glutamic acid decarboxylase increases more than two times during postnatal development (HAYASHI et al., 1989), suggesting that the synthesis of GABA in each cell is enhanced during postnatal maturation.

Effects of a bite-raising splint on the duration of the chewing cycle and the EMG activities of masticatory muscles during chewing in freely moving rabbits

Metal bite-raising splints of 0.5 mm thickness were attached to the upper molar teeth on both sides of the jaw in rabbits. The effects of these splints on masticatory behaviour during the chewing of soft food (bread) by freely moving rabbits were investigated. We recorded electromyograms (EMGs) of the masseter and digastric muscles. The animals exhibited prolongation of the chewing cycle, decreased EMG activity of the masseter muscle and increased EMG activity of the digastric muscle during chewing after introduction of the bite-raising splints. The effects of the splints on the activities of masticatory muscles were abolished by bilateral sectioning of the maxillary and inferior alveolar nerves. It seems likely that afferents from oral sensory receptors were responsible for the changes in masticatory behaviour after the introduction of the occlusal splint.

Detailed analysis of phenotypes of macrophages infiltrating glomeruli in rat anti-Thy1 nephritis

A phenotypic analysis of infiltrating macrophages in rat anti-Thy1 glomerulonephritis induced by monoclonal antibody (mAb) 1-22-3 was carried out using recently reported macrophage-specific mAbs. This was combined with a more detailed quantitative analysis, counting positive cells in isolated glomeruli, to obtain more information on the roles played by macrophages in glomerulonephritis. In normal glomeruli a small number of ED1- or OX-3(anti-Ia)-positive cells but almost no ED2-, TRPM-3- or Mar-3-positive cells were observed. ED1-positive cells increased from 2 h and peaked between days 3 and 7 after mAb injection. TRPM-3-positive cells increased from day 3 and peaked on day 7, later than ED1. The numbers of OX-3-positive cells changed in parallel with those of ED1-positive cells. Mar-3, which stained blood monocytes and ED2, which is an indicator oftissue-fixed resident macrophages, did not react with glomerular infiltrating macrophages. In a double staining study, about 40% of ED1- or OX-3-positive cells costained with TRPM-3 on day 3 and the percentage increased on day 7, but hardly any cells were positive for TRPM-3 alone. This results in two different phenotypes (ED1+,ED2-,OX-3+,Mar-3-, TRPM-3- and ED1+,ED2-,OX-3+,Mar-3-,TRPM-3+) of infiltrating macrophages. We conclude that in rat anti-Thy1 glomerulonephritis, monocytes/macrophages may infiltrate the mesangium, rapidly changing their phenotype (Mar-3+ to Mar-3-) and resulting in a gradual shift to TRPM-3-positive, activated macrophages.

Effects of Kamikihi-To, a traditional Chinese medicine, on behavioral changes induced by methyl-beta-carboline-3-carboxylate in mice and rats

The effects of Kamikihi-To (KMK), a traditional Chinese medicine, on behavioral changes induced by methyl-beta-carboline-3-carboxylate (beta-CCM) were evaluated in mice and rats. Beta-CCM, an anxiogenic benzodiazepine receptor inverse agonist (3.0 mg/kg, i.v. administered 1 min before the test), decreased the locomotor activity of mice in a novel environment. Furthermore, beta-CCM (0.1 mg/kg, i.v. administered 10 min before the test) facilitated the suppression of drinking behavior induced by punishment in the water lick conflict test in rats. KMK (1.0 and 2.0 g/kg, p.o. administered 1 hr before the test) antagonized the decreased locomotor activity in the beta-CCM-treated mice. KMK (2.0 g/kg, p.o.) also recovered the suppression of drinking behavior in the beta-CCM-treated rats. KMK (2.0 g/kg, p.o.) had no effect on beta-CCM-untreated mice and rats in these tests. These findings suggest that KMK has a protective effect against beta-CCM-induced behavioral changes.

Rainbow trout SOX9: cDNA cloning, gene structure and expression

We have isolated and characterized rainbow trout SOX9 cDNA and genomic clones. The cDNA encodes a protein of 488 amino acids (aa) with an HMG box and has 70% aa sequence identity with human SOX9. The rainbow trout and human SOX9 genes show a similar gene structure, and the two introns in the coding region are located at conserved positions. In rainbow trout, the SOX9 mRNA was prominent in testis and brain.

Involvement of protein kinase C in the activation of extracellular signal-regulated kinase 1/2 by UVC irradiation

UVC irradiation activates mitogen-activated protein kinases (MAPKs), including ERK, JNK, and P38. This study examined the role of protein kinase C (PKC) in the regulation of UVC-stimulated MAPKs activation. Either the depletion of PKC by prolonged treatment of cells with 12-O-tetradecanoylphorbol-13-acetate (TPA) or the inhibition of PKC by a selective PKC inhibitor, UCN-01-ME, attenuated UVC-activation of ERK1/2, keeping the activation of JNK1/2 intact. However, K252a, a non-selective PKC inhibitor, inhibited the activation of both ERK1/2 and JNK1/2 by UVC. In three isoforms of PKC (alpha, delta, epsilon) examined, PKC epsilon shows the most evident translocation, a temporal association with cell membrane, upon the UVC irradiation of NIH 3T3 cells. These results suggest that PKC is acting in the UVC-dependent activation of ERK1/2, and PKC epsilon is one of the PKC isozymes playing such a role.

[Pathological examination of radial artery--as a graft material for coronary artery bypass grafting]

To evaluate the usefulness of the radial artery (RA) as a graft material for coronary artery bypass grafting (CABG), the histologic studies of the RA were performed. Specimens were obtained from both sides of 10 RAs during the operations. The degree of arteriosclerosis was evaluated by two methods. The one was microscopic examination by a pathologist, while the other was used by NIH Image 1.57 system. Using this system, the pathological index of arteriosclerotic change was expressed as a ratio (Rx: internal luminal area/tunica media area) of the cross section. From the pathological view the tunica media of RA was rich in smooth muscle cells and poor in elastic fiber. And there was little arteriosclerosis in this artery. The mean Rx of the proximal side of RA was 0.177 +/- 0.033 and that of the distal side was 0.258 +/- 0.132. There was no significant difference between the two, but the proximal side of the RA was slightly larger than the distal. These results showed that RA has a low grade of arteriosclerosis. This was confirmed on microscopic examination. According to these results, the RA can be expected to be a suitable bypass material for CABG.

Viscoelastic properties of the pig temporomandibular joint articular soft tissues of the condyle and disc

It has been suggested that a sustained loading condition such as clenching could compress the temporomandibular joint (TMJ) articular soft tissues. However, there is still no clear understanding of how the TM joint articular tissues respond under compression. To answer this question, we performed in vitro indentation tests on fresh articular discs and cartilage-bone systems of the condyles of 10 Yorkshire pigs (aged 7 months) using a self-developed indentation tester. The indenter was 5 mm in diameter and was controlled by means of a computer-aided feedback mechanism. Bilateral condyles from the same mandible were uniformly prepared; one was used for measurements under sustained compression (SC) and the other for measurements under intermittent compression (IC). The displacements of the indenter induced by a SC of 10, 20, and 30 Newtons (N, units of force) for 10 min and by an IC, also of 10, 20, and 30 N, with one-second duration and two-second intervals for 10 min were measured by means of a displacement sensor with a resolution of 0.001 mm. From these data, the indentation curves of the articular discs and the cartilage-bone systems were calculated. Both the disc and the articular cartilage showed characteristic displacement vs. time curves-namely, an instantaneous deformation upon load application, followed by a time-dependent creep phase of asymptotically increasing deformation under constant load. However, the indentation curves of the two tissues were not identical: The deformation of the articular cartilage was dose-dependent, but that of the disc was not. Moreover, the articular cartilage deformed significantly less under IC than under SC. This difference was not found in the disc. It can be concluded that both the disc and the articular cartilage of the pig temporomandibular joint have viscoelastic properties against compression; however, the disc is stiffer than the articular cartilage.

[Composite arterial conduits with internal thoracic artery and radial artery for a myocardial revascularization]

From April 1996 to December 1996, 15 patients were submitted to myocardial revascularization using composite arterial conduit with internal thoracic artery (ITA) and radial artery (RA). The age ranged from 51 to 76 years (mean age, 65.7 years); Forty patients were male. All patients had double or triple vessel disease or LMT disease. We used 28 arterial conduits including 15 left ITAs, 15 RA, 9 right gastroepiploic artery and one inferior epigastric artery. 15 RAs were anastomosed to LITAs and 15 composite arterial conduits were constructed (branched in 15). There was no operative deaths. Early postoperative angiographic controls demonstrated 93.3% (14/15) patency of composite grafts in 14 of 15 patients. The composite arterial graft using ITA and RA is feasible and the anastomoses so performed are completely safe.

[Microscopic foci of urachal carcinoma in an incidentally detected urachal cyst: a case report]

A 33-year-old man who had been treated for chronic prostatitis was diagnosed to have urachal cysts by transabdominal ultrasonography. Cystoscopy revealed protuberance at the dome of the bladder. Computerized tomography scan and magnetic resonance imaging showed the mass to be mostly cystic but partly solid. Resection of the urachal cysts and partial cystectomy were performed. Histopathologically, most cysts had a normal cylindrical epithelium with retention of mucinous substance. However, several small cysts contained epithelial cells resembling tubulo-villous adenoma and showing mitotic figures. This case was concluded as urachal carcinoma detected in its very early stage.

Temporary cement remnants as an adhesion inhibiting factor in the interface between resin cements and bovine dentin

This study investigated the effect of temporary cement remnants on freshly prepared dentin in the adhesion of resin cements. The tensile bond strength of three types of resin cements to dentin were measured in a control group and after the application of two types of temporary cement. Scanning electron microscopy and energy dispersive x-ray spectroscopy were used to confirm the presence of temporary cement remnants. Overall results suggest that temporary cement application significantly decreased the tensile bond strength in all adhesive systems (P = 0.0001, analysis of variance). Scanning electron micrographs presented granular elements on the dentin surfaces treated with temporary cement even after preconditioning. Energy dispersive x-ray spectroscopy results showed the presence of zinc peaks in the specimens that was not present in the control.

Induction of transplantation tolerance in adult rats by vascularized spleen transplantation

It was demonstrated by Bitter-Seurmann et al. that tolerance to subsequent skin allografts can be brought about, in some rat strain combinations, by heterotopic spleen allografts. We report here that in adult rats, tolerance can be also induced by vascularized spleen allografts using various strain combinations. DA (RT1av1) rats always accepted major histocompatible complex (MHC)-compatible but minor histocompatibility antigen (miH)-incompatible ACI (RT1av1) spleen grafts spontaneously, and further that those DA rats bearing ACI spleen grafts accepted subsequent ACI skin grafts indefinitely. In contrast, Fischer 344 (RT1lvl) rats always accepted not only the "weak" MHC-incompatible Lewis (RT1l) spleen grafts but also subsequent Lewis skin grafts indefinitely, when recipients were administered a short course of FK506 only at the time of primary spleen transplantation. Furthermore, in a number of MHC- and miH-incompatible strain combinations, recipients always accepted primary spleen grafts indefinitely when given a short course of FK506, but those recipients bearing donor spleens revealed split tolerance, that is, rejected subsequent donor-specific skin grafts but accepted heart grafts indefinitely. We conclude that the spleen seems to be a possible organ to induce transplantation tolerance, and that even if the MHC and miH are mismatched, unresponsiveness to at least heart grafts can be achieved by the administration of additional FK506 at the time of spleen transplantation.

Relationship between respiratory failure and plasma noradrenaline levels in amyotrophic lateral sclerosis

We evaluated plasma noradrenaline (NA) levels at test and during head-up tilt test in 20 patients with sporadic amyotrophic lateral sclerosis (ALS). Their fasting plasma NA levels ranged from 195 to 4227 pg/ml. The average plasma NA level was 483 pg/ml in five ambulatory patients, 341 in two wheelchair-bound patients, 1264 in 11 bedridden patients, and 208 in two respirator-dependent patients whose disability grading was the worst among the four groups. Arterial carbon dioxide (PCO2) was evaluated as a measure of respiratory function. The coefficient of correlation between PCO2 and plasma NA was r = 0.654 (p < 0.01). Either respiratory failure or lower motor neuron dysfunction may relate to the elevation of plasma NA levels. In the two bedridden patients, plasma NA levels and heart rate at rest increased significantly as the disease progressed. Cardiovascular responses to head-up tilting were normal. These data suggest that the elevation of plasma NA levels may be related to progression of respiratory failure and lower motor neuron dysfunction. In conclusion, sympathetic hyperactivity in ALS is considered to be not primary, but secondary to somatic motor disabilities and respiratory failure.

Suppression of tumor growth by the 3' untranslated region of mel-18 in 3Y1 cells transformed by the E6 and E7 genes of human papillomavirus type 18

By introducing a cDNA library derived from rat embryonic fibroblast cells, we isolated several morphologically flat revertants of rat 3Y1 cells transformed by the E6 and E7 genes of human papillomavirus type 18 (HPV18). From one of the revertants, we recovered a 0.2-kb cDNA, N56, that suppresses the tumor growth of the transformed 3Y1 cells irrespective of the expression of the E6 and E7 genes. The nucleotide sequence of the cDNA was shown to be identical to that of the 3' untranslated region of a putative mammalian polycomb group gene, mel-18.

The influence of observer calibration in temporomandibular joint magnetic resonance imaging diagnosis

OBJECTIVE

This study was undertaken to investigate the potential of reducing observer variation through a calibration program.

STUDY DESIGN

The study was based on three sets of randomly selected temporomandibular joint magnetic resonance images. Each set consisted of bilateral images from 20 consecutive patients with temporomandibular disorders. As a baseline, three well-experienced noncalibrated investigators interpreted the images individually for disk position and disk configuration. After the initial interpretation, interobserver agreement was calculated as a kappa index and presented to the examiners. On the same occasion, the investigators analyzed agreement between them on the criteria to be used.

RESULTS

Overall data in this study showed an increase in the frequency of interobserver agreement with regard to disk position after the calibration trials were instituted. With regard to disk configuration, substantial interindividual variations were observed even after the observers reached consensus as to the criteria to be used.

CONCLUSIONS

These data suggest that after calibration trials, it is possible for three examiners to obtain reliable and reproducible results in reporting temporomandibular joint disk position on magnetic resonance images.