Impact of the Coronavirus Disease 2019 Pandemic on Dental Visits in Japan

PURPOSE

This study aimed to clarify the impact of the coronavirus disease 2019 (COVID-19) pandemic on individual dental-visit behaviour and examine the difference between elderly and other individuals regarding the impact on dental visits.

MATERIALS AND METHODS

An interrupted time-series analysis was performed to examine the change in data from the national database before and after the first declaration of a state of emergency.

RESULTS

The number of patients visiting a dental clinic (NPVDC), number of dental treatment days (NDTD) and dental expenses (DE) during the first declaration of a state of emergency decreased by 22.1%, 17.9%, and 12.5% in the group under 64 years of age and 26.1%, 26.3%, and 20.1% in the group over 65 years of age, respectively, compared with those in the same month of the previous year. Between March and June 2020, the monthly NPVDC and NDTD were significantly reduced (p < 0.001, p = 0.013) in those over 65 years of age. The DE did not change statistically significantly in either the under 64 group or the over 65 group. There was no statistically significant change in the slope of the regression line in the NPVDC, NDTD, and DE before and after the first state-of-emergency declaration.

CONCLUSION

The first state of emergency greatly reduced the NPVDC, NDTD, and DE compared to those in the previous year. In people aged over 65 years, it might still be unresolved 2 years after the postponement of dental treatment owing to the first declaration of a state of emergency.

Short-term efficacy of exercise therapy for temporomandibular disorders: a case control study

[Purpose] This study compared the short-term outcomes of manual therapy performed by a dentist and home exercises performed by patients as a single exercise therapy program for temporomandibular joint anterior disc displacement without reduction. [Participants and Methods] In this study we included seventeen patients with temporomandibular joint anterior disc displacement without reduction, moderate or greater temporomandibular joint functional impairment, and no treatment interventions. Patients receiving treatment underwent exercise therapy at the time of their first visit, whereas those in the non-treatment group received only an explanation of the condition. We evaluated the clinical symptoms (maximum painless opening distance, pain on motion and mastication, and degree of difficulty in daily life) at the first visit and at the two-week follow-up visit. [Results] For both groups, maximum painless opening distance and degree of difficulty in daily life improved significantly. For the treatment group, the pain on motion and mastication values significantly improved throughout the assessment period. [Conclusion] An exercise therapy program may be useful for the early treatment of temporomandibular joint anterior disc displacement without disc reduction.

Changes in prefrontal cerebral hemodynamics during intermittent pain stimulation to gingiva: Preliminary study using functional near infrared spectroscopy

BACKGROUND/PURPOSE

Elucidating the transmission mechanism of pain signals from the orofacial area and the corresponding modification mechanism will not only aid in the understanding of pain mechanisms but also provide useful information regarding the development of pain mitigation methods. In this study, the involvement of the pain suppression system in the trigeminal area was investigated through an analysis of the activation status over time in the prefrontal cortex using functional near-infrared spectroscopy (fNIRS).

MATERIALS AND METHODS

In 28 healthy, right-handed male volunteers (average age, 30.1 ± 4.2 years) as subjects, a mild, intermittent, acute pain stimulus was administered through the implementation of pocket probing of the gingiva surrounding the right maxillary central incisor. In the prefrontal cortex, the levels of hemoglobin (Hb) were measured using the fNIRS measurement system. Average values of both oxy-Hb and deoxy-Hb were calculated at four stages: rest stage, 20 s prior to the pain stimulus application, and three stages at 20-s intervals within 1 min of stimulation. One-way analysis of variance and multiple comparisons were used to compare representative values to investigate the changes due to pain.

RESULTS

Oxy-Hb levels decreased the most during the 20 s stage directly after stimulus application. This change was seen mainly on the contralateral side, after which it returned to the resting baseline level before the stimulus application.

CONCLUSION

Our data demonstrate that in healthy males, a mechanism exists to mitigate pain involving the pain suppression system in the 20 s after feeling mild pain to the gingiva.

Breakthrough in purification of fossil pollen for dating of sediments by a new large-particle on-chip sorter

Particle sorting is a fundamental method in various fields of medical and biological research. However, existing sorting applications are not capable for high-throughput sorting of large-size (>100 micrometers) particles. Here, we present a novel on-chip sorting method using traveling vortices generated by on-demand microjet flows, which locally exceed laminar flow condition, allowing for high-throughput sorting (5 kilohertz) with a record-wide sorting area of 520 micrometers. Using an activation system based on fluorescence detection, the method successfully sorted 160-micrometer microbeads and purified fossil pollen (maximum dimension around 170 micrometers) from lake sediments. Radiocarbon dates of sorting-derived fossil pollen concentrates proved accurate, demonstrating the method's ability to enhance building chronologies for paleoenvironmental records from sedimentary archives. The method is capable to cover urgent needs for high-throughput large-particle sorting in genomics, metabolomics, and regenerative medicine and opens up new opportunities for the use of pollen and other microfossils in geochronology, paleoecology, and paleoclimatology.

Short-term effects of range-of-motion exercise on temporomandibular joints of patients who undergo disc displacement with reduction of temporomandibular joint

[Purpose] We investigated the short-term effects of an exercise therapy program that combined a range-of-motion exercise for the temporomandibular joint with self-traction therapy for patients with temporomandibular joint disorders who undergo disc displacement with reduction of the painful temporomandibular joint. [Participants and Methods] The program involved 31 patients with moderate or higher functional pain. The range-of-motion exercise for the temporomandibular joint was performed at the first visit by the therapist, and the patients were instructed to perform self-traction therapy in the morning and while bathing for the next 2 weeks, until their next visit. The maximum mouth opening distance and the visual analog scale scores at the first consultation and 2 weeks later were compared to assess the changes in pain on motion and mastication as well as the impact of the program on daily activities. [Results] All symptoms of the patients showed significant improvements after 2 weeks of starting the treatment. [Conclusion] The results of this study suggest that an exercise therapy program combining range-of-motion exercises for the temporomandibular joint and self-traction therapy may be an effective conservative therapy for reducing the pain and obstacles experienced by patients with temporomandibular joint disorders who undergo disc displacement with reduction of the painful temporomandibular joint.

Application of Deep Learning in the Identification of Cerebral Hemodynamics Data Obtained from Functional Near-Infrared Spectroscopy: A Preliminary Study of Pre- and Post-Tooth Clenching Assessment

In fields using functional near-infrared spectroscopy (fNIRS), there is a need for an easy-to-understand method that allows visual presentation and rapid analysis of data and test results. This preliminary study examined whether deep learning (DL) could be applied to the analysis of fNIRS-derived brain activity data. To create a visual presentation of the data, an imaging program was developed for the analysis of hemoglobin (Hb) data from the prefrontal cortex in healthy volunteers, obtained by fNIRS before and after tooth clenching. Three types of imaging data were prepared: oxygenated hemoglobin (oxy-Hb) data, deoxygenated hemoglobin (deoxy-Hb) data, and mixed data (using both oxy-Hb and deoxy-Hb data). To differentiate between rest and tooth clenching, a cross-validation test using the image data for DL and a convolutional neural network was performed. The network identification rate using Hb imaging data was relatively high (80‒90%). These results demonstrated that a method using DL for the assessment of fNIRS imaging data may provide a useful analysis system.

Efficacy of therapeutic exercise for temporomandibular disorders as assessed by magnetic resonance imaging: a case report

[Purpose] The efficacy of exercise therapy in temporomandibular disorders has been recognized. Here, we present our experience with exercise therapy. [Participant and Methods] A 25-year-old female with a sudden onset of mouth opening limitation in October 2018 was admitted to our hospital in November 2018. Based on our initial findings, the patient was diagnosed with left disc derangement of the temporomandibular joint without reduction. A definitive diagnosis was established following magnetic resonance imaging in December 2018. Subsequently, range-of-motion exercises for the temporomandibular joint as passive movements and self-traction therapy as active movements were conducted. Magnetic resonance imaging was repeated 4 months after the first treatment. [Results] The temporomandibular joint disc remained in anterior dislocation during mouth opening and closing. The mouth opening joint motion was significantly improved compared to the pre-therapy range. The pain-related visual analog scale score also significantly improved. [Conclusion] The range of motion of the temporomandibular joint was improved by range-of-motion exercises for the temporomandibular joint, and was maintained and managed using self-traction therapy. Improvement of the range of motion was confirmed by magnetic resonance imaging.

Pilot study of the short-term effects of range-of-motion exercise for the temporomandibular joint in patients with temporomandibular joint disc displacement without reduction

[Purpose] This study investigated the effectiveness of a short-term exercise program combining range-of-motion exercise for the temporomandibular joint and self-traction therapy in patients with temporomandibular joint disc displacement without reduction. [Subjects and Methods] The study participants comprised 36 females with jaw trismus and moderate to severe functional pain. The range-of-motion exercise for the temporomandibular joint was performed at the first visit by the therapist, and the patients were instructed to perform self-traction therapy in the morning and during daily bathing until the next visit 2 weeks later. Maximum mouth opening distance and the visual analogue scale score were used to compare pain on motion and mastication as well as the impact of the program on daily activities at the first consultation and 2 weeks later. [Results] All symptoms were significantly improved after 2 weeks of treatment. [Conclusion] A program that combines exercise for the temporomandibular joint and self-traction therapy can improve range of motion at the joint in the short term and reduce pain and difficulty associated with daily activity in patients with temporomandibular joint disc displacement without reduction. The results of this study suggest that such a program can serve as an effective conservative treatment.

Potential clinical application of masseter and temporal muscle massage treatment using an oral rehabilitation robot in temporomandibular disorder patients with myofascial pain

OBJECTIVES

To investigate the safety, suitable treatment regimen, and efficacy of masseter and temporal muscle massage treatment using an oral rehabilitation robot.

METHODS

Forty-one temporomandibular disorder (TMD) patients with myofascial pain (8 men, 33 women, median age: 46 years) were enrolled. The safety, suitable massage regimen, and efficacy of this treatment were investigated. Changes in masseter muscle thickness were evaluated on sonograms.

RESULTS

No adverse events occurred with any of the treatment sessions. Suitable massage was at pressure of 10 N for 16 minutes. Five sessions were performed every 2 weeks. Total duration of treatment was 9·5 weeks in median. Massage treatment was effective in 70·3% of patients. Masseter muscle thickness decreased with treatment in the therapy-effective group.

CONCLUSION

This study confirmed the safety of massage treatment, and established a suitable regimen. Massage was effective in 70·3% of patients and appeared to have a potential as one of the effective treatments for myofascial pain.

Measurement of cerebral blood volume dynamics during volitional swallowing using functional near-infrared spectroscopy: an exploratory study

The aim of this study was to examine cerebral blood volume dynamics during volitional swallowing using multi-channel functional near-infrared spectroscopy (fNIRS) to understand the basic cortical activation patterns. Fifteen volunteers (age, 26.5±1.3 years, mean±SD) performed volitional swallowing of a 5-ml bolus of water as a task. A 52-channel fNIRS system was used for measuring oxy-Hb levels. We determined the oxy-Hb concentration changes in each channel by calculating the differences between rest and task oxy-Hb levels. Differences in rest and task data were assessed using a paired-t test (p<0.05). A significant increase in oxy-Hb was found in 21 channels. The cortical regions that exhibited increased oxy-Hb concentration included the bilateral precentral gyrus, postcentral gyrus, inferior frontal gyrus, superior temporal gyrus, middle temporal gyrus, and supramarginal gyrus. These data provide a description of cortical activation patterns during volitional swallowing using fNIRS, which will be useful for the evaluation of dysphasia and the effects of the rehabilitation [Corrected].

Can sonographic features be efficacy predictors of robotic massage treatment for masseter and temporal muscle in patients with temporomandibular disorder with myofascial pain?

OBJECTIVE

The aim of this study was to detect sonographic predictors for the efficacy of massage treatment of masseter and temporal muscle in temporomandibular disorders (TMDs) patients with myofascial pain.

METHODS

Thirty-seven TMD patients with myofascial pain (6 men and 31 women, a median age of 45 years) were enrolled. An oral rehabilitation robot massaged the patient's masseter and temporal muscles with a standard massage pressure of 10 N for 16 min. The standard treatment protocol was set five sessions every 2 weeks. The median total duration of treatment was 9.5 weeks. Efficacy of treatment was evaluated based on maximum mouth opening and visual analog scale scores of muscle pain and daily life impediments. The intramuscular echogenic bands and elasticity index ratios of the masseter muscles were evaluated on sonographic or sonoelastographic images obtained before treatment and after the third and last treatment sessions.

RESULTS

The sonographic features detected different changes after the third treatment session between the therapy-effective and therapy-ineffective groups: in the therapy-effective group, the frequency of visibility of the distinct echogenic bands increased, and the elasticity index ratio decreased.

CONCLUSION

Sonographic features after the third treatment session may be useful as predictors of therapeutic efficacy.

Characterization of ASKP1240, a fully human antibody targeting human CD40 with potent immunosuppressive effects

Blocking the CD40-CD154 interaction is reported to be effective for transplantation management and autoimmune disease models in rodents and nonhuman primates. However, clinical trials with anti-CD154 mAbs were halted because of high incidence of thromboembolic complications. Thus, we generated and characterized a fully human anti-CD40 mAb ASKP1240, as an alternative to anti-CD154 mAb. In vitro ASKP1240 concentration-dependently inhibited human peripheral blood mononuclear cell proliferation induced by soluble CD154. In addition, ASKP1240 did not destabilize platelet thrombi under physiological high shear conditions while mouse anti-human CD154 mAb (mu5C8) did. And ASKP1240 itself did not activate platelet and endothelial cells. In vivo administration of ASKP1240 (1 or 10 mg/kg, intravenously) to cynomolgus monkeys, weekly for 3 weeks, significantly attenuated both delayed-type hypersensitivity and specific antibody formation evoked by tetanus toxoid. The immunosuppressive effect was well correlated with the CD40 receptor saturation. Thus, these results suggest that ASKP1240 is immunosuppressive but not prothromboembolic, and as such appears to be a promising therapeutic candidate for the management of solid organ transplant rejection and autoimmune diseases therapy.

Efficacy of massage treatment technique in masseter muscle hardness: robotic experimental approach

The study aimed to clarify the masseter muscle hardness in patients with myofascial pain, to examine their changes after massage, and to analyze whether the hardness can be an index for massage treatment. Sixteen patients with myofascial pain (12 with unilateral and 4 with bilateral masseter muscle pain) and 24 healthy volunteers were enrolled in this study. The masseter hardness between patients and the healthy volunteers was compared. The changes in the hardness in patients after massage were examined. The relation of the hardness with massage regimens and efficacies was analyzed. There was a significant right-and-left difference of the hardness in patients, although there was no difference in the healthy volunteers. The hardness decreased after massage. The pretreatment asymmetry index of the hardness showed a significant correlation with the massage pressure. It was concluded that there was a significant difference between the right and left masseter hardness in patients with myofascial pain. After massage treatment, the masseter hardness and right-and-left difference decreased. The hardness may be an index for determining the massage pressure.

Maximum permissible load weight of a Taishuh pony at a trot

The aim of this study was to determine the loading capacity of a trotting Taishuh pony by gait analysis using a motion analysis system. Seven Taishuh Ponies (5 mares and 2 geldings) and their rider were fitted with a marker (70 mm in diameter placed on their chest) and recorded by 2 high-resolution digital DVD cameras (at a sampling frequency of 60 Hz) as they were trotting along a straight course. Each horse performed 7 tests: 1 test with a loaded weight of 70 kg, 5 tests with random loaded weights between 80 kg and 120 kg, and a final test with a loaded weight of 70 kg again. Three-dimensional movements of each marker were analyzed using motion capture system. The time series of the vertical displacements of the marker was subjected to spectrum analysis by the maximum entropy method, and the autocorrelation coefficient was calculated. The first 2 peaks of the autocorrelation were defined as symmetry and regularity of the gait, and the sum of symmetry and regularity was defined as stability. The cross-spectrum analysis (Blackman-Tukey method) also was performed to analyze the time lag and cross-correlation coefficient between the time series of both pony and rider. Among ponies, symmetry in the 120 kg test (0.54) was significantly lower than that in the first 70 kg test (0.75, P < 0.05) and stabilities in the 100 kg (1.17) and 120 kg (1.17) tests were significantly less than that in the first 70 kg (1.46, P < 0.05). Regarding the rider, there were no significant differences in symmetry, regularity, and stability between loaded weights. The time lag between the time series of horse and rider in the 120 kg test (47.6 ms) was significantly greater than that in the first 70 kg (14.3 ms, P < 0.05) test. These results suggests that the maximum permissible load weight of the Taishuh pony trotting at 3.0 m/s over a short distance was less than 100 kg, which is 43% of the BW.

Masseter muscle sonographic features as indices for evaluating efficacy of massage treatment

OBJECTIVE

The aim of this study was to clarify the sonographic features of the masseter muscle as indices for judging the efficacy of massage treatment.

STUDY DESIGN

Fifteen patients with temporomandibular disorder (10 with unilateral and 5 with bilateral muscle pain) underwent massage treatment alternately on the bilateral masseter and temporal muscles with an oral rehabilitation robot. Sonography was performed before and after treatment, and the masseter thickness and existence of anechoic areas were evaluated.

RESULTS

The thickness on the symptomatic side in the unilateral group significantly decreased after treatment. Anechoic areas were shown in 20 muscles (66.7%) before treatment, and disappeared or were reduced in size in 17 muscles (85.0%) after treatment. The pretreatment thickness was significantly related to visual analog scale (VAS) scores regarding posttreatment muscle pain and massage impression. The existence of anechoic areas was relevant to VAS scores regarding muscle pain.

CONCLUSION

Masseter thickness and existence of anechoic areas might be related to the therapeutic efficacy regarding muscle pain.

Characterization of a 2,4-dinitrochlorobenzene-induced chronic dermatitis model in rats

Although many mouse models of atopic dermatitis have been reported, few rat models have been studied. In this study, a rat chronic allergic dermatitis model was developed and evaluated as a pharmacological model of atopic dermatitis. Prominent ear thickening and scratching were induced after the application of 2,4-dinitrochlorobenzene to the right ear of Brown Norway rats 3 times per week for 3 weeks. Histopathologically, infiltration of T cells in the ear was observed on day 7, and eosinophils and mast cells were found in addition to T cells on day 21. The expression of interferon-gamma and interleukin-4 was increased on day 7 when compared with normal rats. However, interferon-gamma expression had disappeared by day 21. Tacrolimus ointment applied after ear tissue thickening fully developed, suppressed chronic dermatitis in a dose-dependent manner. This model has some symptomatic and histopathological similarities to atopic dermatitis and might be useful in pharmacological studies.

Use of sonographic elastography of the masseter muscles for optimizing massage pressure: a preliminary study

To examine the stiffness of the masseter muscle using sonographic elastography and to investigate its relationship with the most comfortable massage pressure in the healthy volunteers. In 16 healthy volunteers (10 men and 6 women), the Masseter Stiffness Index (MSI) was measured using EUB-7000 real-time tissue elastography. They underwent massages at three kinds of pressures using the Oral Rehabilitation Robot (WAO-1). A subjective evaluation regarding the comfort of each massage was recorded on the visual analogue scale. Elastography was also performed in two patients with temporomandibular joint dysfunction with the myofascial pain. The mean MSI of the right and left muscles in the healthy volunteers were 0.85 +/- 0.44 and 0.74 +/- 0.35 respectively. There was no significant difference between the right and left MSI in the healthy volunteers. The MSI was related to massage pressure at which the healthy men felt most comfortable. The two temporomandibular disorder patients had a large laterality in the MSI. The MSI was related to the most comfortable massage pressure in the healthy men. The MSI can be one index for determining the massage pressure.

Asymmetric Activation of Motor Cortex Controlling Human Anterior Digastric Muscles During Speech and Target-Directed Jaw Movements

Like most of the cranial muscles involved in speech, the trigeminally innervated anterior digastric muscles are controlled by descending corticobulbar projections from the primary motor cortex (M1) of each hemisphere. We hypothesized that changes in corticobulbar M1 excitability during speech production would show a hemispheric asymmetry favoring the left side, which is the dominant hemisphere for language processing in most strongly right handed subjects. Fifteen volunteers aged 24.5 ± 5.3 (SD) yr participated. All subjects were strongly right handed as reported by questionnaire. A surface electromyograph (EMG) was recorded bilaterally from digastrics and jaw movement detected by an accelerometer attached to a lower incisor. Focal transcranial magnetic stimulation (TMS) was used to assess corticomotor excitability of the digastric representation in M1 of both hemispheres during four tasks: 1) static isometric contraction of digastrics; 2) speaking a single word; 3) visually guided, nonspeech jaw movement that matched the jaw kinematics recorded during task 2; and 4) reciting a sentence. Background EMG was well matched in all tasks and jaw kinematics were similar around the time of the TMS pulse for tasks 2–4. TMS resting thresholds and digastric muscle-evoked potential (MEP) size during isometric contraction did not differ for TMS over left versus right M1. MEPs elicited by TMS over left, but not right M1 increased in size during speech and nonspeech jaw movement compared with isometric contraction. We conclude that left corticobulbar M1 is preferentially engaged for descending control of digastric muscles during speech and the performance of a rapid jaw movement to match a target kinematic profile.

Changes in electrical resistance of sound fissure enamel in first molars for 66 months from eruption

The purposes of this study were to investigate the enamel maturation process in the occlusal pit of sound first molars by measuring electrical resistance. Ninety-nine sound first molars in 34 children (mean age of 6.47 +/- 0.51 years) were measured electrically once every 6 months and were monitored for a maximum of 66 months. Electrical resistance increased during the posteruptive period. However, the results suggest that posteruptive enamel maturation in the occlusal pits may not be completed even 66 months after tooth eruption.

Fluoride Intake from Food and Liquid in Japanese Children Living in Two Areas with Different Fluoride Concentrations in the Water Supply

The purpose of this study was to estimate the average daily amount of fluoride from the diet ingested by Japanese children of ages susceptible to dental fluorosis in two areas with different fluoride concentrations in the water supply. Thirty-eight children aged 2-8 years participated in a survey of fluoride intake. Twenty-one out of 38 children lived in an area in which the community water fluoride concentration was an average of 0.555 ppm (moderate fluoride area: MFA), and 17 lived in a low fluoride area (LFA), which ranged between 0.040 and 0.131 ppm. To measure the fluoride intake, diets were collected with a duplicate-diet technique. The fluoride concentrations in each sample were measured using the diffusion technique of Taves and the electrode technique. Meanwhile, after clinical examinations for dental caries and fluorosis, 228 subjects aged 13-15 years were selected for analysis from the same communities. The mean DMFT in the MFA was significantly lower than that in the LFA. The severest grade of dental fluorosis observed was 'very mild' according to Dean's fluorosis index in both areas. The total daily fluoride intakes were 0.0252-0.0254 mg F/kg/day in the MFA and 0.0126-0.0144 mg F/kg/day in the LFA. Differences in the fluoride concentration of drinking water in this study were reflected in the fluoride intake from the diet in a typical Japanese diet.

Balanitis caused by Streptococcus pyogenes: a report of two cases

Streptococcus pyogenes (the Lancefield group A streptococcus) is a cause of pharyngitis and impetigo. However, it has rarely been implicated as a sexually transmitted pathogen. We herein report two cases of severe balanitis due to S. pyogenes in sexually active men. It is postulated that penile cellulitis developed following the invasion of S. pyogenes through a traumatic abrasion acquired during fellatio performed by commercial sex workers. Both patients were treated successfully with oral administration of penicillin.

Ultrasonographic features of the masseter muscle in female patients with temporomandibular disorder associated with myofascial pain

OBJECTIVE

The purpose of the present study was to examine ultrasonographic appearances in female patients with temporomandibular disorder (TMD) associated with myofascial pain in comparison with healthy volunteers.

STUDY DESIGN

The thickness of the masseter muscle in 25 female patients with TMD was measured at rest and at maximum contraction using ultrasonography. The visibility and width of the internal echogenic bands of the masseter muscle were also assessed and the muscle appearance was classified as 1 of 3 types: type I, characterized by the clear visibility of the fine bands; type II, thickening and weakened echo-intensity of the bands; type III, disappearance or reduction in number of the bands.

RESULTS

There were significant differences in the thickness at rest and the increase ratio by contraction between the patient and control groups. The distribution of muscle types showed a significant difference between the 2 groups.

CONCLUSION

The ultrasonographic features of the masseter muscle in TMD patients with myofascial pain were clarified and they might be related to muscle edema.

Tumour Lines from a Spontaneous Rat Endometrial Stromal Sarcoma, Showing Dendritic Cell-like and Myofibroblastic Cell-like Phenotypes

A transplantable tumour (RY) and cell lines (RY-PB and clone RY-B-E3 isolated from RY-PB) were established from a naturally occurring endometrial stromal sarcoma (ESS) found in a 24-month-old female F344 rat. The primary tumour and RY tumours, which had been serially passaged in syngeneic female rats up to the 10th generation, consisted of spindle or round cells arranged in ill-defined bundles or sheets. Neoplastic cells of the primary and RY tumours, as well as cultured cells of RY-PB and RY-B-E3, showed positive reactions to vimentin, ED1/ED2 (both for rat macrophages/histiocytes), OX6 (for dendritic cells expressing rat MHC class II antigens), and lysosomal enzymes such as acid phosphatase and non-specific esterase, in varying degrees. Ultrastructurally, neoplastic cells characteristically had tubulovesicular system-like structures and variously developed lysosomes in the cytoplasm. Neoplastic cells also exhibited immunoexpression to an alpha-smooth muscle actin (alpha-SMA). The addition of transforming growth factor (TGF)-beta1 to RY-PB and RY-B-E3 cultures increased the number of alpha-SMA-positive cells, whilst the positive cell number was decreased by anti-TGF-beta antibody. The RT-PCR method revealed the expression of TGF-beta1 mRNA in the cultured cells. The present study showed that rat ESS-derived cells exhibited dendritic cell-like and myofibroblastic cell-like phenotypes. The histogenesis of ESSs in human beings and rats remains poorly understood, and these tumour lines may therefore become useful tools for further research.

Fluoride mouth rinsing proficiency of Japanese preschool-aged children

AIM

To determine whether Japanese preschool-aged children swallow fluoride solution while rinsing and how much fluoride was retained in the mouth after rinsing.

METHODS

The subjects were 769 children who participated in a school-based fluoride mouth rinse programme (FMR) using 0.05% sodium fluoride solution daily. The group of younger, mean age of 4 years and 10 months, experienced the FMR for two months, and the group of older children, mean age of 5 years and 4 months, did it for at least 8 months, rinsing for a minute using 7 ml of the solution. The amount of fluoride retained in the mouth was estimated as the amount present in the net rinsing solution prepared minus what returned to the solution expectorated.

RESULTS

No child swallowed all the solution. The rate of fluoride retained was 12.0% (mean = 0.19 mg) in the younger group and 10.7% (mean = 0.17 mg) in the older. Only six children retained over 0.5 mg of fluoride. With the extra survey using weekly intervals, the amount retained was below 0.5 mg in all children.

CONCLUSION

That Japanese preschoolaged children could perform fluoride mouth rinsing safely and efficiently.

Effect of FK506 eye drops on late and delayed-type responses in ocular allergy models

BACKGROUND

It is well-known that FK506 strongly inhibits cytokine production by T cells in vitro. However, less evidence is available from in vivo studies of ocular allergy.

OBJECTIVE

To study the anti-inflammatory effect of FK506 eye drops on late and delayed-type responses in several animal models of ocular allergy.

METHODS

Rats and guinea-pigs were sensitized with egg albumin (EA) in adjuvant and later challenged by topical EA application to their eyes to examine the late response. Biopsy specimens of conjunctiva were stained with haematoxylin-eosin or stained for T cells and eosinophils. In addition, rats, rabbits and guinea-pigs were sensitized with complete Freund's adjuvant and later challenged by injecting purified protein derivatives for the delayed-type response. Bulbar conjunctival oedema and hyperaemia were graded by score in rabbits, and Evans blue (EB) extravasation was measured in rats and guinea-pigs. FK506 (0.01-1%) and steroid (0.1%) eye drops were instilled in the eyes of animals several times, before and after challenge.

RESULTS

FK506 eye drops inhibited T cell and eosinophil infiltration in the late response and EB extravasation in the delayed-type response in rats. Also, they inhibited conjunctival oedema, hyperaemia and ocular mucus in the delayed-type response in rabbits. These effects were similar to those of steroid eye drops (betamethasone sodium phosphate, fluorometholone). FK506 eye drops also inhibited inflammatory cell infiltration, the loss of conjunctival epithelium and decrease of goblet cells in the late response as well as EB extravasation in the delayed-type response in guineapigs, a steroid-resistant species.

CONCLUSION

FK506 eye drops inhibit late and delayed-type responses in animal models of ocular allergy.

Characterization of newly established tumor lines from a spontaneous malignant schwannoma in F344 rats: nerve growth factor production, growth inhibition by transforming growth factor-beta1, and macrophage-like phenotype expression

Transplantable tumor (KE) and clone cell (KE-F11) lines were established from a spontaneous malignant schwannoma found in an aged F344 rat. The primary tumor and KE tumors consisted of oval or spindle cells arranged in ill-defined bundles. Cultured KE-F11 cells exhibited polygonal or spindle configurations. Immunohistochemically, neoplastic cells in KE and KE-F11 reacted to vimentin, S-100 protein, neuron-specific enolase, myelin basic protein, and glial fibrillary acidic protein in varying degrees, indicating neurogenic features; occasional cells reacted to alpha-smooth muscle actin. Cells positive for lysosomal enzymes (acid phosphatase and non-specific esterase), and ED1 (rat macrophage specific) were observed in KE-F11, and electron microscopically, cells with many lysosomes were frequently present, indicating expression of macrophage-like phenotypes. Bioassay analysis revealed that KE-F11 cells produced high levels of nerve growth factor. DNA synthesis was inhibited by addition of transforming growth factor-beta1 (TGF-beta1), and Northern blot analysis revealed that expression of c-myc, a cell cycle-related immediate early gene, was depressed by TGF-beta1. Likely, TGF-beta1 is a factor capable of inhibiting cellular growth of Schwann cells. mRNA expression of the low-density lipoprotein receptor-related protein (LRP) was seen in KE-F11 cells by Northern blot analysis, and the level was decreased by lipopolysaccharide (LPS) treatment. LRP may be attributable to regulation of Schwann cell functions. KE-F11 cells seeded on laminin-coated dishes exhibited more extended cytoplasmic projections than on collagen type I-coated dishes. The present study provides evidence that biological properties of malignant schwannoma-derived cells might be affected by exogenous factors such as TGF-beta1, LPS and laminin. These tumor lines may be useful for studies on pathobiological characteristics of Schwann cells.

Correlation of elevated level of blood midkine with poor prognostic factors of human neuroblastomas

The heparin-binding growth factor midkine (MK) is the product of a retinoic acid-responsive gene, and is implicated in neuronal survival and differentiation, and carcinogenesis. We previously reported that MK mRNA expression is elevated in neuroblastoma specimens at all stages, whereas pleiotrophin, the other member of the MK family, is expressed at high levels in favourable neuroblastomas. As MK is a secretory protein, it can be detected in the blood. Here, we show a significant correlation of the plasma MK level with prognostic factors of neuroblastomas. The plasma MK level was determined in 220 patients with neuroblastomas, and compared with that in children without malignant tumors (n=17, <500 pg ml(-1)). The plasma MK level became significantly elevated with advancing stages (stage 1: 445 pg ml(-1) (median), n=73; stage 2: 589, n=39; stage 3: 864, n=40; stage 4: 1445, n=56; and stage 4S: 2439, n=12). More importantly, a higher MK level was strongly correlated with poor prognostic factors: over 1 year of age (P=0.0299), MYCN amplification (P<0.0001), low TrkA expression (P=0.0005), nonmass screening, sporadic neuroblastomas (P<0.0001), and diploidy/tetraploidy (P=0.0007). Thus, these results demonstrate that the plasma MK level is a good marker for evaluating the progression of neuroblastomas. Moreover, considering the ability of antisense MK oligodeoxyribonucleotide to suppress tumour growth of colorectal carcinoma cells in nude mice, as recently reported, the present study suggests that MK is a possible candidate molecular target for therapy for neuroblastomas.

Participation of different macrophage populations and myofibroblastic cells in chronically developed renal interstitial fibrosis after cisplatin-induced renal injury in rats

To shed some light on the mechanisms behind renal fibrogenesis, the present study immunohistochemically investigated the participation of different macrophage populations and myofibroblastic cells in rat renal interstitial fibrosis developed chronically after repeated injection of cisplatin (2 mg/kg body weight, once weekly for 7 weeks). During the 19-week recovery period after the final injection, fibrotic lesions progressively developed in the corticomedullary junction, with the greatest level at post-final injection (FPI) week 5, and then the lesions were gradually repaired by PFI week 19, indicative of a healing process. In conformity with the development of fibrotic lesions, the number of myofibroblastic cells reacting with an anti-alpha-smooth muscle actin antibody was increased, with a peak at PFI week 3, and collagens (types I, III, and IV), fibronection, and laminin were excessively accumulated in these areas. Interstitial cells forming the fibrotic lesions showed mitotic activity at the early stages, whereas they disappeared by apoptosis in the healing process. A large number of cells reacting with an antibody of ED1 (for exudate macrophages), ED2 (for resident macrophages), or OX6 (for major histocompatibility complex class II-presenting macrophages and interstitial dendritic cells) had already appeared at PF1 week 1, and then their numbers increased, with a peak at PFI weeks 7, 3, and 9 in ED1-, ED2-, and OX6-positive cells, respectively. Thereafter, the number of ED1- and ED2-positive cells decreased, whereas the number of OX6-positive cells persisted at a high level until PFI week 19. In the healing process, clusters of lymphocytes were present, the development of which might have been related to OX6-positive cells. The present study demonstrated that chronically developing rat renal interstitial fibrosis might be produced by the complicated mechanisms evoked by interactions between different macrophage populations and myofibroblastic cells, because macrophages show heterogeneous functions depending on microenvironmental factors.

Characterization of Ascaris-induced biphasic skin allergic reaction model in mice: possible roles of mast cells in early-phase and CD4-positive T cells in late-phase reactions

We established an Ascaris-induced biphasic skin allergic reaction in mice. In the early-phase reaction (EPR), mast cell degranulation was observed, and tranilast inhibited ear edema. In mast-cell-deficient mice (WBB6F(1)-W/W(V) mice), ear edema in the EPR disappeared, whereas that in the late-phase reaction (LPR) remained. Eosinophils increased, and CD4-positive T cells tended to increase in the LPR. Anti-CD4 antibody, anti-IL-4 antibody and anti-IL-5 antibody all inhibited ear edema and had a tendency to inhibit eosinophil infiltration in the LPR. These data suggest that the EPR is induced by histamine released from mast cells, whereas the LPR is induced by IL-4 and IL-5 produced from CD4-positive T cells.

Three-dimensional angioarchitecture in transplantable rat fibrosarcomas

Three-dimensional angioarchitecture in a transplantable fibrosarcoma (SS) in F344 rats was investigated by scanning electron microscopy (SEM) of vascular corrosion casts. Tumours were produced in syngeneic rats by implantation of a tumour fragment from another SS tumour. Viable SS tumours, observed up to post-implantation (PI) week 5, showed a high degree of vascularization, consisting of arterioles and veins, and intertwining capillaries branching from such vessels. The capillaries showed numerous finger-like outgrowths, indicating active sprouting of endothelial cells and contributing to tumour growth. In contrast, SS tumours in rats given a single dose (4 mg/kg/bodyweight) of cisplatin at PI week 1 were reduced in volume, lacking in capillary outgrowths, and of low vascular density. Necrotic areas in SS tumours were surrounded by capillaries with sharp tips and wrinkled surfaces. Thus, the findings indicated differences in three-dimensional angioarchitecture between vigorously developing tumours and (1) tumours degenerating as the result of treatment with an anti-cancer drug, or (2) necrotic tumour tissues. SEM of vascular corrosion casts may prove useful for the evaluation of neovascularization in mesenchymal tumours.

Rhodium(I)-catalyzed asymmetric 1,4-addition of arylboronic acids to alpha,beta-unsaturated amides

The conjugate addition of arylboronic acids to alpha,beta-unsaturated amides was carried out in the presence of a chiral rhodium catalyst and an aqueous base. The catalyst prepared in situ from Rh(acac)(CH(2)=CH(2))(2) and (S)-binap provided (R)-N-benzyl-3-phenylbutanamide with 93% ee in the addition of phenylboronic acid to N-benzyl crotonamide. The reaction suffered from incomplete conversion resulting in moderate yields, but addition of an aqueous base, such as K(2)CO(3) (10-50 mol%) was found to be highly effective to improve the chemical yields. The role of the base giving a RhOH species active for transmetalation with arylboronic acids was discussed.

Brainstem auditory regions in mice: expression of nociceptin/orphanin FQ precursor mRNA in select neurons

Nociceptin peptide-receptor system is known to be essential for the regulation of hearing ability. The mRNA for nociceptin precursor protein is highly expressed in the brainstem. We explored a detailed hybridohistochemical expression pattern of the nociceptin precursor mRNA in the mouse brainstem, and identified positive cells in several auditory brainstem nuclei. Positive cells were seen in the dorsal and ventral nuclei of the lateral lemniscus, the rostral periolivary region, the lateroventral and medioventral periolivary nuclei, the dorsal periolivary region, the superior paraolivary nucleus, and the external cortex and dorsal cortex of the inferior colliculus. Of these, the medioventral and lateroventral periolivary nuclei, the major sites of origin of olivocochlear bundle, were most populated by positive cells.

Atopic dermatitis-like skin lesions induced by topical application of mite antigens in NC/Nga mice

BACKGROUND

Atopic dermatitis (AD) is a chronic relapsing inflammation usually observed in patients with an individual or a familial history of atopic diseases, precipitated by environmental factors including mite antigens (Ag). However, the exact etiology of AD is unclear. To further explore the pathogenesis and treatment of AD, a suitable animal model is necessary. In this study, we developed a new animal model of AD induced by mite Ag in NC/Nga mice.

METHODS

We injected the extracts of mite Ag intradermally at the ventral side of the ear of SPF NC/Nga mice on days 0, 2, 4, 7, 9, 11, 14 and 16, and measured the clinical symptoms and the ear thickness. On day 18, we collected blood and submandibular lymph nodes (LN) of the immunized ear to perform a histochemical analysis, and to measure the plasma immunoglobulins and cytokines.

RESULTS

The NC/Nga mice immunized with mite Ag suffered from AD-like skin lesions including erythema followed by edema, excoriation and scaling. The histological and immunohistochemical examinations of the affected skin showed epidermal hyperplasia with hyperkeratosis, severe infiltration of CD4+ T lymphocytes, eosinophils and macrophages, and degranulation of mast cells. The total plasma IgE level was markedly elevated in mite Ag-treated mice. LN cells of mice immunized with mite Ag synthesized IgE in an Ag-dependent manner and secreted interleukin-4 (IL-4) and IL-5 but not interferon-gamma.

CONCLUSIONS

NC/Nga mice treated with mite Ag manifest clinical and immunological aspects similar to patients with AD, suggesting that this model is suitable for exploring the pathogenesis of human AD.

Colour Doppler sonographic analysis of blood-flow velocity in the human facial artery and changes in masseter muscle thickness during low-level static contraction

Muscle oedema, which can be seen as a thickness increment by ultrasonography, is important in provoking pain and fatigue during low-level contraction. Although oedema is related to the balance of inflow and outflow of blood, there are no data on the correlation between muscle thickness change and blood-flow. Blood-flow velocities in the facial artery and the muscle thickness changes were measured by colour Doppler ultrasonography in 30 healthy volunteers during 20 min contraction with 10% of maximum force. Thickness and velocity changes both reached a peak in the initial phase of contraction. The initial change of thickness did not correlate with the velocity in the facial artery, while those immediately after exercise showed a high correlation. The velocity changes in the facial artery might depend on both the general response to contraction and local metabolic or mechanical factors in the contracted masseters.

FK506 is superior to methotrexate in therapeutic effects on advanced stage of rat adjuvant-induced arthritis

OBJECTIVE AND DESIGN

The anti-arthritic properties of FK506 were compared with methotrexate (MTX) in established adjuvant-induced arthritis (AIA) in rats.

MATERIAL

Female Lewis rats.

TREATMENT

Arthritic rats were orally administered with FK506 (1-5.6 mg/kg) and MTX (0.1-1 mg/kg) from days 15-24.

METHODS

Arthritis was induced by injection of Mycobacterium tuberculosis into the right hind footpad on day 0. Efficacy was determined on the basis of paw inflammation measured by paw volume and histological change, hyperalgesia and grip strength. Grip strength measurement was employed as an indication of function of paws in arthritic rats. Peripheral white blood cell (WBC) counts and thymus weights were measured, mainly as indicators of toxic side effects.

RESULTS

FK506 suppressed paw inflammation and hyperalgesia without toxic effects on WBC and thymus in established AIA. MTX slightly suppressed paw inflammation and hyperalgesia at the highest dose (1 mg/kg). Toxic effects were observed at lower doses than the effective treatment dose with MTX. Grip strength was found to decrease during development of AIA. FK506, but not MTX, treated rats recovered grip strength loss.

CONCLUSIONS

The results show that FK506 is more effective and less toxic than MTX in treating established AIA in rats.

Effects of FK506 and other immunosuppressive anti-rheumatic agents on T cell activation mediated IL-6 and IgM production in vitro

The objective of this study was to investigate the therapeutic potential of FK506 and other immunosuppressive agents for the treatment of rheumatoid arthritis (RA), focusing on the effects on in vitro IL-6 production and IL-6-mediated immune response. We employed an in vitro model producing IL-6 via T cell activation in human PBMC, based on the hypothesis that T cells play a central role in the pathogenesis of RA. FK506 potently inhibited IL-6 production from PBMC stimulated with anti-CD3 and anti-CD28 monoclonal antibody (anti-CD3/CD28). Cyclosporin A (CsA) also inhibited the anti-CD3/CD28 induced IL-6 production but was about 100 times less potent than FK506. Dexamethasone (DEX) inhibited both anti-CD3/CD28 and LPS induced IL-6 production at almost the same concentration. Methotrexate (MTX) did not affect cytokine production. Anti-CD3/CD28 stimulated PBMC culture supernatants were found to enhance IgM production in SKW6.4 cells. The effects of anti-CD3/CD28 stimulated culture supernatants in the presence of agents on IgM production in SKW6.4 cells were investigated. FK506 and CsA led to suppression of IgM production induced by culture supernatants probably via inhibition of IgM inducible cytokine production from PBMC. DEX profoundly enhanced IgM production, although IL-6 production from PBMC was strongly inhibited by the agent. MTX decreased IgM production although it has no inhibitory effect on IL-6 production. The present study suggests that FK506 is the most effective among the four agents for the suppression of IL-6 production and IL-6-mediated autoantibody production in T cell activation related autoimmune diseases such as RA.

Three-dimensional image display without special eyeglasses: observation of magnetic resonance angiography using the stereoscopic liquid crystal display

The authors have developed a new stereoscopic liquid crystal display that provides real-time 3-dimensional image viewing without special eyeglasses. The device consists of 3 major parts: (1) an image display composed of a 10.4-inch color liquid crystal plate with a resolution of 640 x 480, (2) an automatic head tracking system, and (3) a special backlight unit for the right and left eyes. Eight radiologists interpreted 60 cases of magnetic resonance angiography (29 cases of cerebrovascular disease and 31 normal cases) to compare film display and the liquid crystal display (ie, pseudo 3-dimensional display and true 3-dimensional display). Using a continuously distributed scale ranging from 0% to 100%, the observers ranked their confidence levels in determining the presence or absence of steno-occlusive disease, aneurysm, and arteriovenous malformation (AVM) and their locations. For statistical evaluation, receiver operating characteristic (ROC) analysis and Brier score were used. For detecting AVM, film reading showed a significantly higher value in the area under the binormal ROC curve (Az) than did pseudo-3-dimensional display (P < .05). Excluding this, however, no significant difference existed in Az values among the 3 viewing methods. Also, there was no significant difference in Brier score between not only the stereoscopic view and nonstereoscopic view groups, but also the senior and junior groups. Subjective estimation of true 3-dimensional display showed that vessels were more distinguishable with less eye fatigue compared with stereoscopic film reading. The stereoscopic liquid crystal display provided almost equal efficacy to film reading; however, the short optimum distance for observation and the low resolution should be improved.

Biorecognizable HPMA copolymer-drug conjugates for colon-specific delivery of 9-aminocamptothecin

N-(2-hydroxypropyl)methacrylamide (HPMA) copolymer conjugates for colon-specific delivery of 9-aminocamptothecin (9-AC) were designed. They hold 9-AC bound via spacers containing amino acid residues and aromatic azo bonds. In vitro release profiles of 9-AC from HPMA copolymer conjugates were evaluated under artificial conditions that simulated large intestinal azoreductase and peptidase activities. The studies indicated that the azo bond was reduced first, followed by the release of unmodified 9-AC from the 9-AC containing fragment by peptidases. Release profiles depended on the chemical structure of the peptide part of the spacer. Conjugates containing leucylalanine showed high colon-specific release of 9-AC when compared to alanine containing conjugates. It appears that the studied conjugates are suitable as colon-specific drug delivery systems.

The variation on the mutagenicity of CNP during anaerobic biodegradation

The mutagenicity of water, including herbicide CNP, and its time-variation during anaerobic biodegradation were studied through Ames assay using strains with or without. S9 mix: TA98, TA 100, YG1021, YG1024, YG1026, and YG1029. The bacteria, for the anaerobic biodegradation, was obtained from a paddy field, and preincubated for a month. The CNP was decomposed in an anaerobic culture inoculated with the bacteria, and finally yielded CNP-amino as one of the CNP metabolites. About 16% of the initial CNP was transformed into CNP-amino by the 14th day. The mutagenicities to TA98. YG1024, and YG1029 strains with S9 mix increased with cultivating time, the latter two showed the strongest sensitivity to CNP-amino. The contribution of CNP to the mutagenicity decreased as the chemical decomposed, while the contribution of CNP-amino increased. However, the increased mutagenicity was not limited to the contribution of CNP-amino. but also to the contribution of other metabolites. The contributions of other CNP metabolites were 67% of total mutagenicity to the TA98 strain and 30% to the YG1029 strain. These unknown mutagenic metabolites were the indirect frameshift mutagens which did not have nitro- and amino-substituents, and the indirect base-pair mutagens which might possibly have some amino-substituents.

Differential effects of transforming growth factor-beta1, a fibrogenic factor, on macrophage-like cells (HS-P) and myofibroblastic cells (MT-9) in vitro

Transforming growth factor-beta1 (TGF-beta1) produced by infiltrating macrophages plays a role in fibrotic disorders through the induction of myofibroblasts. To explore possible mechanisms by which TGF-beta1 may act in this context, we investigated effects of TGF-beta1 on macrophage-like (HS-P) and myofibroblastic (MT-9) cells, two novel cell lines developed by us. Immunocytochemically, the addition of TGF-beta1 (0, 0.1, 0.5, and 1.0 ng/ml) dose-dependently suppressed the expressions of antigens recognized by macrophage/histiocyte-specific antibodies (ED1 and ED2) in HS-P cells, whereas the addition concomitantly increased the number of anti-alpha-smooth muscle actin antibody-positive myofibroblastic cells, suggesting a possible phenotypical modulation of macrophages into myofibroblasts in the fibrotic lesions. By contrast, MT-9 cells did not show such immunophenotypical changes following TGF-beta1 addition. DNA synthesis, measured by tritiated thymidine-incorporation, was inhibited in a dose-dependent manner in MT-9 cells by TGF-beta1 addition (0, 0.1, 0.2, 0.5, 1.0, 5, and 10 ng/ml), but that in HS-P cells was unchanged. Northern blot analysis revealed that expressions of cell cycle-related early genes, c-jun and c-myc, were increased in HS-P cells after TGF-beta1 (1 ng/ml) addition, with c-jun showing peak expression prior to c-myc. By contrast, the peak expressions of c-jun and c-myc were delayed in TGF-beta1 (1 ng/ml)-added MT-9 cells, and their levels were less in MT-9 cells than in HS-P cells. Furthermore, TGF-beta1 (1 and 10 ng/ml) induced DNA laddering in MT-9 cells, but did not in HS-P cells. Based on these findings, it was speculated that TGF-beta1 could have induced G1 arrest in cell cycle and apoptosis in MT-9 cells. The present study showed that there were significant differences in the effects of TGF-beta1 between macrophage-like HS-P cells and myofibroblastic MT-9 cells, presumably depending on divergent susceptibilities to TGF-beta1 between both cell types. Because such cell types are key cells in the fibrogenesis, HS-P and MT-9 might be useful models for investigating the pathogenesis of fibrosis in vitro.