Perforation of the temporomandibular joint disc: cadaveric anatomical study

The aim of this human cadaveric study was to investigate the relationship between temporomandibular joint disc perforation and bony changes of the mandibular condyle. Overall, 135 cadaveric mandibles were used (69 male, 66 female; all White). Mean age at death was 78.7 years. Perforation of the disc was investigated. Differences in the area of the perforation according to the different types of bony change (erosion, flattening, osteophyte) were evaluated. Perforation of the disc was observed in 34.8% of all mandibles, occurring unilaterally in 53.2% of cases and bilaterally in 46.8%. The prevalence of perforation was 16.4% in cadavers <80 years old (67 heads) and 52.9% in those ≥80 years old (68 heads) (P < 0.001). Osteophyte formation was always identified along with other bony changes (21.7%) and never in isolation. The area of the perforation was significantly larger in the groups with bony changes (one, two, or three changes) than in the 'no bony change' group. The group with osteophyte formation showed a significantly larger perforated area than the group without osteophyte formation; likewise, the group with flattening showed a significantly larger perforated area than the group without flattening. Osteophytes and flattening are probably secondary bony changes that occur following disc perforation. Based on this study, disc perforation should be suspected when these findings are identified on imaging.

Coexistence of muscle atrophy and high subcutaneous adipose tissue radiodensity predicts poor prognosis in hepatocellular carcinoma

Introduction

We aimed to assess the prognostic implications of muscle atrophy and high subcutaneous adipose tissue (SAT) radiodensity in patients with hepatocellular carcinoma (HCC).

Methods

In this retrospective study, muscle atrophy was assessed using the psoas muscle index (PMI) obtained from computed tomography. SAT radiodensity was evaluated based on radiodensity measurements. Survival and multivariate analyses were performed to identify factors associated with prognosis. The impact of muscle atrophy and high SAT radiodensity on prognosis was determined through survival analysis.

Results

A total of 201 patients (median age: 71 years; 76.6% male) with HCC were included. Liver cirrhosis was observed in 72.6% of patients, and the predominant Child-Pugh grade was A (77.1%). A total of 33.3% of patients exhibited muscle atrophy based on PMI values, whereas 12.9% had high SAT radiodensity. Kaplan-Meier survival analysis demonstrated that patients with muscle atrophy had significantly poorer prognosis than those without muscle atrophy. Patients with high SAT radiodensity had a significantly worse prognosis than those without it. Muscle atrophy, high SAT radiodensity, the Barcelona Clinic Liver Cancer class B, C, or D, and Child-Pugh score ≥ 6 were significantly associated with overall survival. Further classification of patients into four groups based on the presence or absence of muscle atrophy and high SAT radiodensity revealed that patients with both muscle atrophy and high SAT radiodensity had the poorest prognosis.

Conclusion

Muscle atrophy and high SAT radiodensity are significantly associated with poor prognosis in patients with HCC. Identifying this high-risk subgroup may facilitate the implementation of targeted interventions, including nutritional therapy and exercise, to potentially improve clinical outcomes.

Recent prevalence and characteristics of patients with hepatitis delta virus in Hokkaido, Japan

AIM

Although hepatitis delta virus (HDV) coinfection with hepatitis B virus (HBV) is a global health concern, the global prevalence of HDV infections remains unknown due to insufficient data in many countries. In Japan, HDV prevalence has not been updated for over 20 years. We aimed to investigate the recent prevalence of HDV infections in Japan.

METHODS

We screened 1264 consecutive patients with HBV infection at Hokkaido University Hospital between 2006 and 2022. Patients' serums were preserved and subsequently tested for HDV antibody (immunoglobulin-G). Available clinical information was collected and analyzed. We compared the changes in liver fibrosis using the Fibrosis-4 (FIB-4) index between propensity-matched patients with and without the evidence of anti-HDV antibodies and corrected for baseline FIB-4 index, nucleoside/nucleotide analog treatment, alcohol intake, sex, HIV coinfection, liver cirrhosis, and age.

RESULTS

After excluding patients without properly stored serums and those lacking appropriate clinical information, 601 patients with HBV were included. Of these, 1.7% of patients had detectable anti-HDV antibodies. Patients with anti-HDV antibody serum positivity had a significantly higher prevalence of liver cirrhosis, significantly lower prothrombin time, and a higher prevalence of HIV coinfection than those who demonstrated serum anti-HDV antibody negativity. A propensity-matched longitudinal analysis revealed that liver fibrosis (FIB-4 index) progressed more rapidly in patients with positive results for anti-HDV antibody tests.

CONCLUSIONS

The recent prevalence of HDV infections in Japanese patients with HBV was 1.7% (10/601). These patients experienced rapid liver fibrosis progression, highlighting the importance of routine HDV testing.

Potential Correlation between Changes in Serum FGF21 Levels and Lenvatinib-Induced Appetite Loss in Patients with Unresectable Hepatocellular Carcinoma

Lenvatinib, used for unresectable hepatocellular carcinoma (HCC), causes appetite loss, but the underlying mechanisms, clinical impact, and predictive factors have been unclear. The endocrine factor FGF21 modulates appetite and is involved in cachexia. We evaluated the association between FGF21 level changes during lenvatinib treatment for unresectable HCC and appetite loss. Sixty-three eligible unresectable HCC patients who started lenvatinib treatment between 2018 and 2021 were included. We analyzed FGF21 levels at baseline; 1, 2, and 4 weeks after lenvatinib initiation, and before the onset of appetite loss. Grade ≥ 2 lenvatinib-induced appetite loss led to liver functional reserve deterioration at disease progression and a poor prognosis. Baseline characteristics and serum FGF21 levels were similar between patients with and without appetite loss. However, the serum FGF21 change rate increased significantly at 4 weeks post-lenvatinib initiation in patients with grade ≥ 2 appetite loss, as compared to those without appetite loss. Similar significant increases in the serum FGF21 level change rate were observed prior to grade ≥ 2 appetite loss onset. This suggests that changes in FGF21 levels can be used to predict patients with a greater risk of marked appetite loss and provides insights into the mechanisms underlying lenvatinib-induced appetite loss in patients with HCC.

Hepatitis C virus eradication by direct-acting antivirals causes a simultaneous increase in the prevalence of fatty liver and hyper-LDL cholesterolemia without an increase in body weight

AIM

Hepatitis C virus (HCV) infection has been reported to cause liver steatosis. Thus, eradicating HCV with direct-acting antivirals (DAAs) is expected to reduce liver steatosis. We aimed to clarify long-term changes in the prevalence of fatty liver and hyper-LDL-cholesterolemia and their associations in patients who achieve successful HCV eradication using DAAs.

METHODS

This retrospective study included patients with HCV who achieved sustained virological response (SVR) after interferon-free DAA and analyzed the changes in the prevalence of fatty liver diagnosed with controlled attenuation parameter (CAP), hyper-LDL-cholesterolemia, and their relationships at baseline (n=100) and 24 weeks (SVR24, n=100), 96 weeks (SVR96, n=100), and 144 weeks (SVR144, n=90) after DAA.

RESULTS

In 100 participants, the prevalence of fatty liver (19% vs. 32%, p=0.0349) and hyper-LDL-cholesterolemia (6% vs. 15%, p=0.0379) significantly increased without changes in body weight at SVR96. Median total cholesterol, low-density lipoprotein cholesterol (LDL-C), and small-dense-LDL (sdLDL) levels and CAP values were significantly greater at SVR24, SVR96, and SVR144 than at baseline. Baseline CAP values and changes in CAP values were significantly negatively correlated at every observation point: r=-0.5305, p<0.0001 at SVR24; r=-0.3617, p=0.0005 at SVR96; and r=-0.4735, p<0.0001 at SVR144. A similar relationship was observed in cholesterol levels. Unlike at baseline, CAP values were significantly positively correlated with LDL-C and sdLDL-C levels at all observation points after DAAs.

CONCLUSIONS

DAAs may cause an increased prevalence of fatty liver accompanying hyper-LDL-cholesterolemia without increased body weight. Since post-SVR liver steatosis could cause HCC, careful follow-up may be required.

Epo-C12 inhibits peroxiredoxin 1 peroxidase activity

Epo-C12 is a synthetic derivative of epolactaene, isolated from Penicillium sp. BM 1689-P. Epo-C12 induces apoptosis in human acute lymphoblastoid leukemia BALL-1 cells. In our previous studies, seven proteins that bind to Epo-C12 were identified by a combination of pull-down experiments using biotinylated Epo-C12 (Bio-Epo-C12) and mass spectrometry. In the present study, the effect of Epo-C12 on peroxiredoxin 1 (Prx 1), one of the proteins that binds to Epo-C12, was investigated. Epo-C12 inhibited Prx 1 peroxidase activity. However, it did not suppress its chaperone activity. Binding experiments between Bio-Epo-C12 and point-mutated Prx 1s suggest that Epo-C12 binds to Cys⁵² and Cys⁸³ in Prx 1. The present study revealed that Prx 1 is one of the target proteins through which Epo-C12 exerts an apoptotic effect in BALL-1 cells.

Differences in body composition and grip between Japanese and Thai older people living in Thailand

Background

Age-related muscle mass loss is one of the main risk factors for osteoporosis and fractures among older people. Thus, prevention of muscle mass loss in older people is an important issue. We examined ethnic group-related differences in body composition and grip strength among older people living in the same area.

Methods

We measured body composition and grip strength among local Thai older people living in Chiang Mai Province, as well as in Japanese older people who emigrated to Chiang Mai Province in their retirement. A self-reported questionnaire regarding socio-demographic status was also administered. Measurement items were averaged and compared by sex and ethnic group. Questionnaire items were also categorized by sex and ethnic group.

Results

A total of 119 older people participated, including 47 Japanese participants (26 men, 21 women) and 72 Thai participants (16 men, 56 women). The average age of Japanese participants was 71.1 years (standard deviation: 4.89), and the average age of Thai participants was 68.8 years (standard deviation: 5.61). Significant differences between ethnic groups were found in percentage of body fat in women (Japanese average: 32.9% vs. Thai average: 37.6%, p &lt; 0.05), skeletal muscle mass index (SMI) in men (Japanese average: 7.85 kg/m2 vs. Thai average: 7.31 kg/m2, p &lt; 0.05) and average grip strength in men (Japanese: 35.1 kg vs. Thai: 30.7 kg, p &lt; 0.05).

Conclusions

Our preliminary results suggest that Thai older people, particularly men, are weaker than Japanese older people. Decreased muscle mass is directly responsible for functional impairment, involving loss of strength, increased likelihood of falls, and loss of autonomy. Preventing muscle weakness among older people is important. In future studies, we plan to analyze and clarify the differences between Thai and Japanese older people to identify effective methods to prevent muscle mass decreases.

Key messages

There were significant differences in average % body fat between older Japanese and Thai women. There were significant differences in average SMI and grip strength between older Japanese and Thai men.

A Targeted Genetic Association Study of the Rare Type of Osteomyelitis

Chronic nonbacterial osteomyelitis is a rare bone disorder that can be found in the jaw. It is often associated with systemic conditions, including autoimmune deficiencies. However, little is known about how the genetic and immunologic background of patients influences the disease. Here, we focus on human leukocyte antigen (HLA), killer cell immunoglobulin-like receptors (KIRs), and their specific combinations that have been difficult to analyze owing to their high diversity. We employed a recently developed technology of simultaneous typing of HLA alleles and KIR haplotype and investigated alleles of the 35 HLA loci and KIR haplotypes composed of centromeric and telomeric motifs in 18 cases and 18 controls for discovery and 472 independent controls for validation. We identified an amino acid substitution of threonine at position 94 of HLA-C in combination with the telomeric KIR genotype of haplotype tA01/tB01 that had significantly higher frequency (>20%) in the case population than in both control populations. Multiple logistic regression analysis based on a dominant model with adjustments for age and sex revealed and validated its statistical significance and high predictive accuracy (C-statistic ≥0.85). Structure-based analysis revealed that the combination of the amino acid change in HLA-C and the telomeric genotype tA01/tB01 could be associated with lower stability of HLA-C. This is the first case-control study of a rare disease that employed the latest sequencing technology enabling simultaneous typing and investigated amino acid polymorphisms at HLA loci in combination with KIR haplotype.

Influence of the anatomical form of the posterior maxilla on the reliability of superior maxillary repositioning by Le Fort I osteotomy

Certain patients with facial deformities require superior repositioning of the maxilla via Le Fort I osteotomy; however, the magnitude of superior repositioning of the maxilla is often less than expected. In this study, the correlation between the accuracy of superior repositioning of the maxilla and the anatomical form of the maxillary posterior region was examined. Seventy-five patients who underwent Le Fort I osteotomy without forward movement of the maxilla but with superior repositioning of the maxilla were included in this study. The bone volume around the descending palatine artery (DPA), the angle of the junction between the pterygoid process and the tuberosity, and the distance between the upper second molar and the pterygoid process were measured via three-dimensional analysis. A significant negative correlation (r=-0.566) was found between the bone volume around the DPA and the ratio of repositioning (actual movement divided by expected movement). It is possible that the superior repositioning of the maxilla expected prior to surgery was not sufficiently attained because of the large volume of bone around the DPA. The results of this study show that in some patients, superior repositioning was not achieved at the expected level because of bone interference attributable to the anatomical form of the maxillary posterior region.

Possible association of oestrogen and Cryba4 with masticatory muscle tendon-aponeurosis hyperplasia

OBJECTIVE

Masticatory muscle tendon-aponeurosis hyperplasia, which is associated with limited mouth opening, progresses very slowly from adolescence. The prevalence rates of this disease are higher among women than among men, suggesting oestrogen involvement. As parafunctional habits are frequently observed, mechanical stress is likely involved in the pathogenesis and advancement of this disease. To elucidate the pathological condition, we examined the effect of oestrogen on tenocyte function and the relationship between mechanical stress and crystallin beta A4 (Cryba4), using murine TT-D6 tenocytes.

MATERIALS AND METHODS

Cell proliferation assays, RT-PCR, real-time RT-PCR, Western blot analysis and mechanical loading experiments were performed.

RESULTS

The physiological dose of oestrogen increased the levels of scleraxis and tenomodulin in TT-D6 tenocytes. In contrast, forced expression of Cryba4 inhibited scleraxis expression in these cells. Surprisingly, oestrogen significantly promoted cell differentiation in the Cryba4-overexpressing TT-D6 tenocytes. Moreover, tensile force induced Cryba4 expression in these tendon cells.

CONCLUSION

Oestrogen and Cryba4 may be associated with the progression of masticatory muscle tendon-aponeurosis hyperplasia.

Standard Protocol for Exchange of Health-checkup Data Based on SGML: The Health-checkup Data Markup Language (HDML)

Objectives: To develop a health/medical data interchange model for efficient electronic exchange of data among health-checkup facilities.

Results: A Health-checkup Data Markup Language (HDML) was developed on the basis of the Standard Generalized Markup Language (SGML), and a feasibility study carried out, involving data exchange between two health checkup facilities. The structure of HDML is described.

Results: The transfer of numerical lab data, summary findings and health status assessment was successful.

Conclusions: HDML is an improvement to laboratory data exchange. Further work has to address the exchange of qualitative and textual data.

Flux growth of patterned LiCoO2 crystal arrays directly on a Pt substrate in molten LiNO3

We demonstrate a new way to prepare hollow-structured LiCoO₂ crystals directly on a Pt substrate for the first time through a combination of semi-additive electrodeposition of a Co core and subsequent flux growth in molten LiNO₃.

Proteomics-based identification of novel proteins in temporal tendons of patients with masticatory muscle tendon--aponeurosis hyperplasia

Masticatory muscle tendon-aponeurosis hyperplasia (MMTAH) is a new disease associated with limited mouth opening that is often misdiagnosed as a temporomandibular disorder; subsequently, patients are mistakenly treated with irreversible operations. Due to the poor presentation and characterization of symptoms, the underlying pathological conditions remain unclear. We have previously conducted a proteomic analysis of tendons derived from one MMTAH subject and one facial deformity subject using two-dimensional fluorescence difference gel electrophoresis and liquid chromatography coupled with tandem mass spectrometry. However, the results were obtained for only one subject. The aim of the present study was to confirm the expression of specific molecules in tendon tissues from multiple subjects with MMTAH by applying two-dimensional polyacrylamide gel electrophoresis with matrix-assisted laser desorption ionization time-of-flight mass spectrometry. Of the 19 proteins identified in tendons from both MMTAH and facial deformity patients, fibrinogen fragment D and beta-crystallin A4 were up-regulated, whereas myosin light chain 4 was down-regulated in MMTAH. We also found fibrinogen to be expressed robustly in tendon tissues of MMTAH patients. Our data provide the possibility that the distinctive expression of these novel proteins is associated with the pathology of MMTAH.

Androgen receptor in triple negative breast cancer

The clinical management of triple negative breast cancer (TNBC) is challenging due to the relatively aggressive biological behaviour and paucity of specific targeted therapy. A subset of TNBC patients has been reported to express androgen receptor (AR) in carcinoma cells and the manipulation of androgen signalling or AR targeted therapies have been proposed. However, the biological significance of AR in TNBC has remained relatively unknown. Therefore, this review aims to summarise the reported studies assessing the rates of AR positivity in TNBC patients and androgenic effects in TNBC cell lines. The rates of AR positivity among TNBC cases varied depending on the study population (0-53% of all TNBC patients). This difference among the reported studies may be largely due to the methodological differences of analysing AR. While the majority of cell line studies suggest that androgen increase proliferation and preliminary clinical studies suggest that AR antagonists improve the prognosis of AR positive TNBC patients, cell line transfection experiments and survival analyses of histological samples suggest that the presence of AR in tumour is either benign or predicts better survival. Therefore further translational investigations regarding the mechanisms of androgen action in TNBC are required to explain this discrepancy between clinical and basic studies.

Preliminary results of a study comparing conventional radiography with phase-contrast radiography for assessing root morphology of mandibular third molars

OBJECTIVES

The aim of this study was to evaluate the usefulness of phase-contrast radiography for assessing root morphology of mandibular third molars in comparison with conventional radiography.

METHODS

We studied 37 extracted mandibular third molars. One oral surgeon compared the number of roots and root curvature of the extracted teeth on conventional radiographs with those on phase-contrast images.

RESULTS

The number of roots and root curvature on conventional images differed significantly from those on phase-contrast images.

CONCLUSIONS

Our results suggest the possibility that phase-contrast radiography is more useful than conventional radiography for assessing the root morphology of mandibular third molars.

Long-term results of surgical therapy for masticatory muscle tendon-aponeurosis hyperplasia accompanied by limited mouth opening

Masticatory muscle tendon-aponeurosis hyperplasia is a new disease entity characterized by limited mouth opening due to contracture of the masticatory muscles, resulting from hyperplasia of tendons and aponeuroses. In the case of masseter muscle type, the face displays a square mandible configuration. Pharmacotherapy, occlusal splints and physical therapy are ineffective. This study evaluated the long-term results of aponeurectomy of the masseter muscle with coronoidectomy to release the temporal muscle tendon. The subjects were 10 patients who underwent surgery between 2000 and 2005. Mean maximum mouth opening before surgery was 21.8mm (range 17-29 mm). All patients received bilateral aponeurectomy of the masseter muscle and coronoidectomy. Three patients additionally underwent bilateral anglectomy for esthetic reasons. After discharge, one patient did not return to the hospital. Data from the other nine patients were analyzed. The mean duration of follow-up was 4 years. At final follow-up, the maximum mouth opening was >44 mm in four patients, 40-44 mm in three patients, and 35-39 mm in two patients. Overall satisfaction was excellent or good in all patients.

Terahertz optical clock generation with tunable repetition rate and central wavelength using variable-bandwidth spectrum shaper

Recently, a number of high-speed optical clock generation technologies have been developed due to their potential useful applications in different fields. Here, we propose a new terahertz optical clock generation technique with tunable repetition rate and central wavelength. The proposed optical clock generator consists of an frequency comb light source and a variable-bandwidth spectrum shaper (VBS). The VBS can generate arbitrary repetition rate pulse trains and waveform by controlling each spectral mode. We experimentally demonstrated optical clock generation with repetition rates of 1.28, 2.56, 3.0, and 4.0 THz.

The comparison between pains, difficulties in function, and associating factors of patients in subtypes of temporomandibular disorders

The aim of this study was to compare the multidimensional properties among subtypes of painful temporomandibular disorders (TMD): myofascial pain (group I), disc displacement (group II), arthralgia (group IIIa) and osteoarthritis (group IIIb). A total of 511 patients answered a battery of questionnaires, which included questions relating to intensity and duration of pain, the Japanese version of the McGill Pain Questionnaire, limitation of daily functions, the Hospital Anxiety and Depression Scale, the Eysenck Personality Questionnaire short-form and 34 items of behavioural contributing factors. Group IIIb showed significantly the highest age in all subtypes. Those in group I had higher depression scores than those in group II (P = 0.005). Group IIIa had a lower women's ratio than in group II (P = 0.001) and the patients showed a shorter pain duration than those in groups I (P = 0.000) and II (P = 0.001). Group IIIa patients also showed lower visual analogue scale (VAS) ratings for pain descriptors 'heavy' (P = 0.002) and 'tiring' (P = 0.004) than those of group I, and 'dull' (P = 0.005), 'heavy' (P = 0.001) and 'tiring' (P = 0.005) than those of group II. Group IIIa showed lower ratios of contributing factors of 'an awareness of grinding/clenching during sleep' (P = 0.000) and 'an awareness of clenching sensation when waking up at night' (P = 0.002) than those of group I, and also showed a higher ratio of 'a liking for a hard food' (P = 0.000) and lower ratio of 'talking for a long time on the telephone' (P = 0.001) than those of group II. In conclusion, although several properties were different between subtypes, the majority of them were similar in the four subtypes of TMD.

Pathologic and imaging findings of an oncocytoma in the deep lobe of the left parotid gland

Oncocytoma is a rare salivary gland tumour consisting of oncocytes with many hyperplastic mitochondria. It usually occurs in the parotid gland. Because the features of oncocytoma resemble those of other benign and low-grade-malignant salivary gland tumours, clinical diagnosis is often challenging. This report presents the pathologic and imaging findings of an oncocytoma arising in the deep lobe of the left parotid gland in a 66-year-old man. Oncocytoma was diagnosed on the basis of histological, magnetic resonance imaging, and scintigraphic findings. The tumour showed accumulation of technetium-99m pertechnetate and decreased signal intensity on both T1- and T2-weighted magnetic resonance images.

Standard protocol for exchange of health-checkup data based on SGML: the Health-checkup Data Markup Language (HDML)

OBJECTIVES

To develop a health/medical data interchange model for efficient electronic exchange of data among health-checkup facilities.

RESULTS

A Health-checkup Data Markup Language (HDML) was developed on the basis of the Standard Generalized Markup Language (SGML), and a feasibility study carried out, involving data exchange between two health checkup facilities. The structure of HDML is described.

RESULTS

The transfer of numerical lab data, summary findings and health status assessment was successful.

CONCLUSIONS

HDML is an improvement to laboratory data exchange. Further work has to address the exchange of qualitative and textual data.

Contribution of Thr29 to the thermodynamic stability of goat alpha-lactalbumin as determined by experimental and theoretical approaches

The Thr29 residue in the hydrophobic core of goat alpha-lactalbumin (alpha-LA) was substituted with Val (Thr29Val) and Ile (Thr29Ile) to investigate the contribution of Thr29 to the thermodynamic stability of the protein. We carried out protein stability measurements, X-ray crystallographic analyses, and free energy calculations based on molecular dynamics simulation. The equilibrium unfolding transitions induced by guanidine hydrochloride demonstrated that the Thr29Val and Thr29Ile mutants were, respectively, 1.9 and 3.2 kcal/mol more stable than the wild-type protein (WT). The overall structures of the mutants were almost identical to that of WT, in spite of the disruption of the hydrogen bonding between the side-chain O-H group of Thr29 and the main-chain C=O group of Glu25. To analyze the stabilization mechanism of the mutants, we performed free energy calculations. The calculated free energy differences were in good agreement with the experimental values. The stabilization of the mutants was mainly caused by solvation loss in the denatured state. Furthermore, the O-H group of Thr29 favorably interacts with the C=O group of Glu25 to form hydrogen bonds and, simultaneously, unfavorably interacts electrostatically with the main-chain C=O group of Thr29. The difference in the free energy profile of the unfolding path between WT and the Thr29Ile mutant is discussed in light of our experimental and theoretical results.

Fibrous adhesions in the joint compartment of the temporomandibular joint associated with experimental opposite drawing mandibular ramus in rabbit

The purpose of this study was to develop a rabbit model of fibrous adhesions in the joint compartment of the temporomandibular joint (TMJ) without surgical invasion into the joint compartment. A unilaterally elastic force of about 120 grams was applied from the anterior edge of masseteric tuberosity to the posterior part of the zygomatic arch between the masseteric fascia layer and the subcutaneous layer in 14 rabbits. The blocks of nondrawing side TMJ were removed after four weeks. Fibrous adhesions were observed in 13 rabbits except for one rabbit that lost over 30% of its body weight. In eight of the rabbits, the adhesions were detected in both joint compartments. This animal model for fibrous adhesion of the TMJ will be useful in understanding the pathogenesis of adhesion in human TMJs.

A model for internal derangement and osteoarthritis of the temporomandibular joint with experimental traction of the mandibular ramus in rabbit

OBJECTIVES

The purpose of this study is to make a model of internal derangement (ID) and osteoarthritis (OA) by postero-superior displacement of the mandible in the rabbit temporomandibular joint (TMJ).

MATERIALS AND METHODS

Sixteen Japanese white rabbits (8 months old) were subjected to traction of the mandibular ramus in the postero-superior direction unilaterally using elastic force and five rabbits were used as the control. The operations were performed without surgical invasion of the TMJ capsule. Temporomandibular joint tissue was removed after 4 weeks and Technovit and paraffin sections with or without decalcification were observed histologically.

RESULTS

In contrast to the control group, it showed anterior disc displacement, disc deformity, resorption of subchondral bone and osteophyte formation in the drawing side of the experimental group. Intra-articular fibrous adhesions were observed in both sides.

CONCLUSION

It is concluded that posterosuperior displacement of the mandible caused ID and OA in the rabbit TMJ. This model may contribute to the understanding of the etiology of human temporomadibular disorders (TMD).

Effects of estrogen on thermoregulatory tail vasomotion and heat-escape behavior in freely moving female rats

Effects of estrogen on thermoregulatory vasomotion and heat-escape behavior were investigated in ovariectomized female rats supplemented with estrogen (replaced estrogen rats) or control saline (low estrogen rats). First, we measured tail temperature of freely moving rats at ambient temperatures (T(a)) between 13 and 31 degrees C. Tail temperature of the low estrogen rats was higher than that of the replaced estrogen rats at T(a) between 19 and 25 degrees C, indicating that the low estrogen rats exhibit more skin vasodilation than the replaced estrogen rats. There was no significant difference in oxygen consumption and core temperature between the two groups. Second, we analyzed heat-escape behaviors in a hot chamber where rats could obtain cold air by moving in and out of a reward area. The low estrogen rats kept T(a) at a lower level than did the replaced estrogen rats. These results imply that the lack of estrogen facilitates heat dissipation both by skin vasodilation and by heat-escape behavior. Ovariectomized rats may mimic climacteric hot flushes not only for autonomic skin vasomotor activity but also for thermoregulatory behavior.

KT3-671, an angiotensin AT1 receptor antagonist, attenuates vascular but not cardiac responses to sympathetic nerve stimulation in pithed rats

Effects of KT3-671 on vascular and cardiac sympathetic neurotransmission were investigated in pithed rats. The pressor response to spinal stimulation (5 Hz) of the pithed rat without the adrenals was approximately 75% of that with the adrenals. Guanethidine (8 mg/kg, i.v.) decreased by about 76% the pressor response to sympathetic stimulation in the pithed rat with intact adrenals and the guanethidine-resistant response was almost completely abolished by bilateral adrenalectomy. Therefore, the following experiments were done using the pithed rat without the adrenals. KT3-671 (1-10 mg/kg, i.v.) as well as losartan (1-10 mg/kg, i.v.) inhibited dose-dependently the pressor response to sympathetic stimulation. KT3-671 was approximately four times more potent than losartan in inhibiting the pressor response. The two angiotensin II subtype 1 receptor antagonists (10 mg/kg, i.v.) did not affect the pressor response to exogenously administered norepinephrine. Neither KT3-671 nor losartan influenced the tachycardia induced by spinal stimulation and isoprenaline. Intravenous infusion of angiotensin II (100 ng/kg/min) did not affect both pressor and tachycardic responses to sympathetic stimulation. In conclusion, KT3-671 as well as losartan inhibits vascular but not cardiac sympathetic neurotransmission of the pithed rats, which may contribute to its overall antihypertensive efficacy.

Molecular cloning and characterization of the gene coding for azoreductase from Bacillus sp. OY1-2 isolated from soil

Azo dyes are regarded as pollutants because they are not readily reduced under aerobic conditions. Bacillus sp. OY1-2 transforms azo dyes into colorless compounds, and this reduction is mediated by a reductase activity for the azo group in the presence of NADPH. A 1.2-kbp EcoRI fragment containing the gene that encodes azoreductase was cloned by screening the genomic library of Bacillus sp. OY1-2 with digoxigenin-labeled probe designed from the N-terminal amino acid sequence of the purified enzyme. An open reading frame encoding the azoreductase, consisting of 178 amino acids, was predicted from the nucleotide sequence. In addition, because only a Bacillus subtillis hypothetical protein was discovered in the public databases (with an amino acid identity of 52.8%), the gene encoding the azoreductase cloned in this study was predicted to be a member of a novel family of reductases. Southern blot analysis revealed that the azoreductase gene exists as a single copy gene on a chromosome. Escherichia coli-expressing recombinant azoreductase gave a ten times greater reducing activity toward azo dyes than the original Bacillus sp. OY1-2. In addition, the expressed azoreductase purified from the recombinant E. coli lysate by Red-Sepharose affinity chromatography showed a similar activity and specificity as the native enzyme. This is the first report describing the sequencing and characterization of a gene encoding the azo dye-reducing enzyme, azoreductase, from aerobic bacteria and its expression in E. coli.

Characterization of monoclonal antibodies generated against Norwalk virus GII capsid protein expressed in Escherichia coli

The Norwalk virus (NV) causes outbreaks of acute non-bacterial gastroenteritis in humans. The virus capsid is composed of a single 60 kDa protein. The capsid protein of NV36 (genogroup II, Mexico virus type) was expressed in an Escherichia coli system and ten monoclonal antibodies (MAbs) were generated against it. The reactivity of these MAbs was characterized using enzyme-linked immunosorbent assay (ELISA) and Western blot (WB) analysis towards 20 overlapping fragments of the NV36 capsid protein expressed in E. coli. All of the MAbs recognized sequential (continuous) epitopes on the three antigenic regions. Six of the 10 MAbs recognized fragment 2 (equivalent residues 31-70), three MAbs recognized fragment 13 (residues 361-403) and one MAb recognized fragment 7 (residues 181-220), suggesting that the N-terminal domain (residues 1-220) may contain more antigenic epitopes than the C-terminal domain (residues 210-548). Furthermore, two MAbs (1B4 and 1F6) reacted in WB with three purified NV strains (genogroup II) derived from patients' stool samples. It was also found that genogroup I recombinant NV96-908 (genogroup I, KY89 type) could be detected as sensitively as recombinant NV36 (genogroup II) by ELISA with a set of the MAbs produced here.

Folding-unfolding of goat alpha-lactalbumin studied by stopped-flow circular dichroism and molecular dynamics simulations

Folding reaction of goat alpha-lactalbumin has been studied by stopped-flow circular dichroism and molecular dynamics simulations. The effects of four single mutations and a double mutation on the stability of the protein under a native condition were studied. The mutations were introduced into residues located at a hydrophobic core in the alpha-domain of the molecule. Here we show that an amino acid substitution (T29I) increases the native-state stability of goat alpha-lactalbumin against the guanidine hydrochloride-induced unfolding by 3.5 kcal/mol. Kinetic refolding and unfolding of wild-type and mutant goat alpha-lactalbumin measured by stopped-flow circular dichroism showed that the local structure around the Thr29 side chain was not constructed in the transition state of the folding reaction. To characterize the local structural change around the Thr29 side chain to an atomic level of resolution, we performed high-temperature (at 400 K and 600 K) molecular dynamics simulations and studied the structural change at an initial stage of unfolding observed in the simulation trajectories. The Thr29 portion of the molecule experienced structural disruption accompanied with the loss of inter-residue contacts and with the water molecule penetration in the 400-K simulation as well as in four of the six 600-K simulations. Disruption of the N-terminal portion was also observed and was consistent with the results of kinetic refolding/unfolding experiments shown in our previous report.

A randomized prospective study of oral versus intravenous antibiotic prophylaxis against postoperative infection after sagittal split ramus osteotomy of the mandible

BACKGROUND

We investigated whether oral levofloxacin was as effective as intravenous cefazolin sodium for preventing postoperative infections in patients undergoing sagittal split ramus osteotomy of the mandible.

METHODS

Forty-four patients were randomized to treatment with levofloxacin or cefazolin sodium. Levofloxacin (100 mg t.d.s.) was administered orally, and cefazolin sodium (1 g b.i.d.) by intravenous infusion. Both drugs were given until 5 days postoperatively. The concentrations of levofloxacin in the mandibular bone marrow and serum were measured.

RESULTS

The mean levofloxacin concentration 4 h and 53.7 min after administration was 1.086 microg/ml in serum and 1.328 microg/ml in the mandibular bone marrow. The efficacy rate of levofloxacin was 95% and that of cefazolin sodium was 85.7%, with no significant difference between the two drugs (p = 0.322).

CONCLUSION

Oral administration of levofloxacin is a simple, cost-effective and safe alternative to intravenous antibiotic prophylaxis after mandibular surgery.

Comparison of the effectiveness of arthrocentesis in acute and chronic closed lock: analysis of clinical and arthroscopic findings

The objective of this study was to investigate the effectiveness of temporomandibular joint arthrocentesis in acute and chronic closed lock patients. Eighteen patients with closed lock of the temporomandibular joint (TMJ) were treated with fine needle fiber arthroscopic observation following arthrocentesis. Maximal mouth opening (MMO) and intensity of pain (VAS) were evaluated at pretreatment and each posttreatment appointment (one week, one month, three months following treatment). The clinical and arthroscopic findings were analyzed categorizing two groups into: good (A) and poor (B) groups. At pretreatment there was no significance relative to age or the mean MMO and VAS between the groups, but the mean of duration of the symptoms in group B was significantly longer than in group A (P < 0.03). Group B showed more severe synovitis, adhesions, and chondromalacia than group A (P < 0.01). Results suggest that arthrocentesis is more effective in closed lock of short duration where there is less severe synovitis, adhesions, and chondromalacia.

Autonomic and behavioural thermoregulation in starved rats

1. We investigated the mechanism of starvation-induced hypothermia in rats. 2. Threshold core temperatures (Tcor) for tail skin vasodilatation and cold-induced thermogenesis were determined after a 3 day starvation using a chronically implanted intravenous thermode. Food deprivation significantly lowered the threshold Tcor for heat production, but did not affect the heat loss threshold. 3. Thermogenic response to a fall in Tcor below its threshold was enhanced by starvation. 4. Preferred ambient temperatures (Tpref) and Tcor were measured before and during a 3 day starvation in a thermal gradient. The 3 day starvation significantly lowered Tcor only in the light phase of the day. The level of hypothermia was the same throughout the fasting period, while Tpref gradually increased during the 3 days of starvation. 5. When rats were starved at a constant ambient temperature of 25 C (no thermal gradient), their Tcor levels were comparable with those of the rats kept in the thermal gradient. 6. The results suggest that, in rats, hypothermia caused by starvation was not due to a decrement in thermogenic capability, but was due to a decrease in the threshold for the activation of thermogenesis.

Expression of recombinant Norwalk-like virus capsid proteins using a bacterial system and the development of its immunologic detection

The capsid protein of Norwalk-like virus (NLV) isolates NLV-36 (Mexico virus type, genogroup II [GII]), NLV-21 (Lordsdale virus type, GII), NLV-114 (untyped GII virus), and NLV-96-908 (KY89 virus type, GI) have been expressed in an Escherichia coli system. The expressed recombinant NLV capsid proteins, fused with maltose binding protein (MBP-rV) and thioredoxin (TRX-rV) in E. coli lysate, were analyzed using sodium dodecyl sulfate-polyacrylamide gel eletrophoresis. Rabbit IgG (R-IgG) in hyperimmune serum has been raised against MBP-rV-36 capsid protein and was purified before further study. Detection of TRX-rVs using an enzyme-linked immunosorbent assay (ELISA) showed that R-IgG had immunologic reactivity to GII as well as to the GI rV capsid proteins TRX-rV-36, TRX-rV-21, TRX-rV-114, and TRX-rV-96-908. Results of Western immunoblot (WB) analysis showed the same broad recognition of R-IgG when using the same samples. The results of the ELISA tests on serum samples obtained from patients involved in confirmed outbreaks of NLV proved that expressed NLV capsid proteins in E. coli can be detected by NLV-infected human serum. In addition, purified NLVs (LD virus types) derived from patients' stool could be detected using anti-NLV R-IgG, whereas normal R-IgG did not react when using WB. Our results strongly suggest that the immunologic detection of NLV antigens using anti-rV R-IgG is possible and seems a significant step toward simplification of an NLV detection test.

Preprimed artificial lung for emergency use

We investigated the possibility of preprimed storage of an artificial lung (AL), aiming at facilitating its emergency use. Test ALs, consisting of a special microporous hollow fiber membrane made of polyolefin in which direct blood-gas contact was completely eliminated, were preprimed with saline solution, sterilized by gamma-ray irradiation, and evaluated after 1-3 months of storage at room temperature. A small amount of bubble was noted in the priming solution after storage in some ALs, which most likely originated from the air dissolved in the priming solution or persisted in the liquid compartment at priming. Although the preprimed solution contained several polyolefin-breakdown products due to irradiation, including ethyl alcohol, n- and t-butyl alcohol, acetone, and carbon dioxide, the levels of these substances were at concentrations known to be not toxic. Endotoxin concentration was negligible. In SEM observation, no perceptible microstructural change was observed in the hollow fibers after preprimed storage. Maximum tensile stress and ultimate elongation of the hollow fiber in the test ALs were reduced by approximately 20% and 3%, respectively, from those of the control AL. The influence of preprimed storage on gas-exchange function was examined in a venoarterial bypass animal study using a goat. Oxygen transfer function was well preserved whereas carbon dioxide removal function was slightly lowered according to the storage term in the stored ALs compared with those of a nonpreprimed control AL. On the basis of these results, we conclude that preprimed storage of the AL with gamma-ray sterilization is basically feasible and realistic.

Effects of food deprivation on daily changes in body temperature and behavioral thermoregulation in rats

Homeothermic animals regulate body temperature (T(b)) by using both autonomic and behavioral mechanisms. In the latter process, animals seek out cooler or warmer places when they are exposed to excessively hot or cold environments. Thermoregulation is affected by the state of energy reserves in the body. In the present study, we examine the effects of 4-day food deprivation on circadian changes in T(b) and on cold-escape and heat-escape behaviors in rats. Continuous measurement of T(b) during food deprivation indicated that the peak T(b) amplitude was not different from baseline values, but the trough amplitude continuously decreased after the onset of food deprivation. Cold-escape behavior was facilitated by food deprivation, whereas heat-escape behavior was unchanged. After the termination of food deprivation, the lowered T(b) returned to normal on the first day. However, cold-escape behavior was still facilitated on the third day after food reintroduction. Autonomic and behavioral thermoregulatory effectors are modulated in the face of food shortage so as to maintain optimal performance during the active period, whereas increasing energy conservation occurs during the quiescent phase.

[Consent to enrollment in randomized clinical trials]

Multi-facility joint randomized clinical trials for cancer treatment are the most common method of current clinical study. However, the difference in the rate of participation in multi-facility randomized clinical trials may damage the resulting general validity. Therefore, we studied whether the rate of participation in randomized clinical trials is different between university hospitals and other general hospitals using a questionnaire (with anonymity preserved). There were 744 subjects from university hospitals and 339 from general hospitals participating in the study. The results showed that 10.9 percent of those from university hospitals were willing to participate, against 28.1 percent who were not. Of those from general hospitals (public hospitals in this study) 10.6 percent answered that they would participate and 27.4 percent that they would not. Little difference was found in the rate of participation in randomized clinical trials between university hospitals and other general hospitals. The focus is thus on doctors to solve the possible differences between the facilities in further multi-facility joint studies.

Repeated acute hypoxia temporarily attenuates the ventilatory respiratory response to hypoxia in conscious newborn rats

We asked whether repeated hypoxic exposures during the early neonatal periods could affect the ventilatory control, such as the lung volume-dependent ventilatory inhibition (HBR), pulmonary ventilation (VE), and CO2 production (VCO2). Within each litter of rats, one group of pups (experimental group H) was exposed to 6% O2 (30-min duration twice a day from postnatal d 1 to 4). The other group (control group C) was exposed to air. At 5 d after birth, the HBR was triggered by lung inflation via negative body surface pressure (10 cm H2O). Measurements of VE and VCO2 were done by plethysmography and the inflow-outflow CO2 difference, respectively. At 2 wk of age, VE and VCO2 measurements were repeated by the barometric technique and the inflow-outflow CO2 difference, respectively. Each conscious pup was breathing normoxia (21% O2) and then hypoxia (10% O2). Results were as follows: 1) during normoxia, HBR was stronger and both VE and VCO2 were higher in H pups than in C pups; 2) during hypoxia, the HBR of C was as in normoxia, whereas that of H was increased above the normoxic value; 3) during hypoxia, C maintained VE, whereas H decreased it; 4) in hypoxia, VCO2 was reduced significantly in both groups; 5) at 2 wk of age, VE and VCO2 did not differ between H and C during normoxia or in response to 10% hypoxia. We conclude that in rat pups, repeated hypoxic episodes can modify the HBR and, at least temporarily, reduce the VE response to hypoxia with a decrease in VCO2. The findings are in agreement with the view that repeated hypoxic exposures in the neonatal period could interfere with the development of respiratory control and could possibly be involved in the mechanisms of neonatal apnea or sudden infant death syndrome.

Effect of the extra n-terminal methionine residue on the stability and folding of recombinant alpha-lactalbumin expressed in Escherichia coli

The structure, stability, and unfolding-refolding kinetics of Escherichia coli-expressed recombinant goat alpha-lactalbumin were studied by circular dichroism spectroscopy, X-ray crystallography, and stopped-flow measurements, and the results were compared with those of the authentic protein prepared from goat milk. The electric properties of the two proteins were also studied by gel electrophoresis and ion-exchange chromatography. Although the overall structures of the authentic and recombinant proteins are the same, the extra methionine residue at the N terminus of the recombinant protein remarkably affects the native-state stability and the electric properties. The native state of the recombinant protein was 3.5 kcal/mol less stable than the authentic protein, and the recombinant protein was more negatively charged than the authentic one. The recombinant protein unfolded 5.7 times faster than the authentic one, although there were no significant differences in the refolding rates of the two proteins. The destabilization of the recombinant protein can be fully interpreted in terms of the increased unfolding rate of the protein, indicating that the N-terminal region remains unorganized in the transition state of refolding, and hence is not involved in the folding initiation site of the protein. A comparison of the X-ray structures of recombinant alpha-lactalbumin determined here with that of the authentic protein shows that the structural differences between the proteins are confined to the N-terminal region. Theoretical considerations for the differences in the conformational and solvation free energies between the proteins show that the destabilization of the recombinant protein is primarily due to excess conformational entropy of the N-terminal methionine residue in the unfolded state, and also due to less exposure of hydrophobic surface on unfolding. The results suggest that when the N-terminal region of a protein has a rigid structure, expression of the protein by E. coli, which adds the extra methionine residue, destabilizes the native state through a conformational entropy effect. It also shows that differences in the electrostatic interactions of the N-terminal amino group with the side-chain atoms of Thr38, Asp37, and Asp83 bring about a difference in the pKa value of the N-terminal amino group between the proteins, resulting in a greater negative net charge of the recombinant protein at neutral pH.

Developmental changes in urinary elimination of theophylline and its metabolites in pediatric patients

We investigated the developmental changes in the pattern of urinary metabolites of theophylline, a substrate for CYP1A2, to study when CYP1A2, which is absent in the perinatal period, fully develops during childhood. The urinary ratios of three metabolites (1-methyluric acid, 3-methylxanthine, and 1,3-dimethyluric acid) to theophylline in patients over 3 y of age show a much larger interindividual variation compared with those under 3 y of age, and the mean values of the ratios in patients over 3 y of age were greater than those in patients under 1 y of age. The urinary ratio of 1,3-dimethyluric acid (a metabolite generated by several cytochrome P450s) to 3-methylxanthine or 1-methyluric acid (metabolites generated by CYP1A2 exclusively) seemed to be relatively constant over 3 y of age; in patients under 3 y of age, these ratios were much higher than those in patients over 3 y of age. The urinary ratio of 1-methyluric acid to 3-methylxanthine or 3-methylxanthine to 1-methyluric acid seemed to be relatively invariable in all patients except those less than 1 y of age. These findings suggest that CYP1A2 activity may be programmed to mature by around 3 y of age and that CYP1A2 probably plays a major role in theophylline 8-hydroxylation at a therapeutic concentration after the full development of CYP1A2 activity.