Surgical resection for accessory spleen torsion: A case report

INTRODUCTION

Accessory spleen torsion is extremely rare, and surgery is often the emergency or elective treatment of choice.

PRESENTATION OF CASE

A 20-year-old female with no specific medical history presented to our outpatient clinic with a chief complaint of abdominal pain. The patient was diagnosed with accessory spleen torsion by computed tomography. However, the abdominal symptoms and inflammatory reaction based on blood tests were mild, so a conservative treatment was selected. Subsequently, blood tests were normalized, and imaging studies showed that the accessory spleen was shrinking. Contrast-enhanced examination showed contrast enhancement in a portion of the infarcted accessory spleen region, indicating that the accessory spleen torsion had been released. Surgical resection was performed to prevent possible future re-torsion and hemorrhage of the accessory spleen.

DISCUSSION

The removed specimen seemed to be normal accessory spleen tissue with clear infarcted foci edges. This artery showed evidence of luminal organization and untwisting of the occluded artery.

CONCLUSION

This accessory spleen torsion was treated conservatively; however, the patient was referred for surgical treatment.

Reduction en masse of inguinal hernia: MDCT findings of two cases

Reduction en masse of inguinal hernia is an extremely rare complication arising from manual reduction of a hernia. The hernial content remaining in the hernia sac returns above the inguinal canal but remains in the abdominal wall. Accurate preoperative diagnosis of reduction en masse of inguinal hernia is challenging because the hernia appears to be reduced upon physical examination. We experienced two cases of reduction en masse. In both cases, multidetector row computed tomography revealed a closed loop obstruction near the inguinal fossa. In addition, we observed a continuous tract of the hernia sac to the inguinal canal and prominent peritoneal thickening suggestive of the hernia sac.

Steady-State Visually Evoked Fields (SSVEF) associated with affective emotions

The aim of this study was to examine the SSVEFs associated with the processing of positive and negative impression images. We used the International Affective Picture System (IAPS) which is increasingly used in brain imaging studies to examine emotional processes. Their images also allow valence to be systematically investigated. All 200 images were categorized into three categories of "negative ", "positive " and "neutral " individually according to valence assessed by each subject after the MEG measurement. The peripheral square, i.e., frame, of the image was flickered black and white at 15 Hz while the image was kept stationary. Those images were randomly presented for 2.0 s on screen set at 120 cm in front of the subject. Ten healthy subjects participated. MEG recordings were made with a 122-channel whole-head MEG system in a magnetically shielded room. We made two-dipoles estimation of the averaged MEG signals and obtained the amplitude of souse waveform in 15 Hz component (using a band-pass filter at 14-16 Hz) of SSVEF in occipital area. The amplitude of the SSVEF source in the occipital area was larger for the negative impression images than the positive impression images (p<0.05). This result suggests that the amplitude of SSVEF that originated from the surrounding field of visual object was modulated by the emotional object and that the SSVEF could be a measure of emotion of subjects.

On fuzzy modeling using fuzzy neural networks with the back-propagation algorithm

A fuzzy modeling method using fuzzy neural networks with the backpropagation algorithm is presented. The method can identify the fuzzy model of a nonlinear system automatically. The feasibility of the method is examined using simple numerical data.

Portal blood flow via the peribiliary vascular plexus demonstrated by contrast-enhanced ultrasonography with Sonazoid

PURPOSE

We report two cases in which portal blood flow via the peribiliary vascular plexus (PBP) was clearly demonstrated using contrast-enhanced intra-operative ultrasonography (CE-IOUS).

METHODS

Two patients who underwent hemihepatectomies were investigated using CE-IOUS. Before injection of the contrast medium, both the hepatic arterial and portal venous flows of the hemiliver to be resected were interrupted by ligating those corresponding vessels at the hepatic hilum. Subsequently, the perfluorobutane microbubbles were injected intravenously.

RESULTS

In the early vascular phase, a remarkable intermittent flow was visualized in the lumen of the portal branches whose inflows were interrupted. The flow of the portal vein then disappeared as a result of ligating the hepatic duct concomitantly with the surrounding connective tissue. We considered that the portal venous flow appearing under the condition of total disruption of original inflow was supplied from the hepatic artery through the PBP.

CONCLUSIONS

This is the first report of blood flow via the PBP in human liver visualized by dynamic image study.

Stochastic resonance in connectivity between both auditory areas obtained by auditory stimuli

We examined coherence of auditory steady state responses (ASSRs) in magnetoencephalogram to an ongoing sinusoidal amplitude modulated tone presented to the subject's left ear while bursts of white noise of various intensities were presented to the right ear. The results showed a significant enhancement in the real part of coherence of ASSRs obtained from the right and left temporal regions by the presence of white noise of appropriate intensity. The observed stochastic resonance (SR) most likely occurred within the central nervous system, which is from lateral superior olive to medial geniculate body. Our finding may be quite important as mechanisms of SR in biological systems are mostly unknown.

Administration of dalteparin based on the activated clotting time for prophylaxis of hepatic vessel thrombosis in living donor liver transplantation

Beginning in 2004, dalteparin doses based on activated clotting time (ACT) were administered for hepatic vessel thrombosis prophylaxis in living donor liver transplantation (LDLT). We verified the feasibility of this new therapy by comparing it with the previous one. From 1993 through 2008, 42 metabolic liver patients who underwent LDLT were divided into two groups. Group A (1993-2003, n = 32) was administered a fixed dalteparin dose and a large amount of fresh frozen plasma (FFP); Group B (2004-2008, n = 10) was administered an appropriate dosage of dalteparin to maintain the ACT levels from 140 to 150 seconds and a small amount of FFP. Group B was administered a lesser amount of FFP and more dalteparin. This resulted in longer activated partial thromboplastin time, lower fibrinogen degradation products D-dimer, and lower aspartate aminotransferase levels compared to group A; all differences were significant. Group B showed neither thrombotic nor hemorrhagic complications. Anticoagulation therapy comprising adjustment of the dalteparin dose based on ACT reduces thrombotic complications without increasing hemorrhagic complications. ACT measurement is a simple, reliable method for bedside monitoring of dalteparin anticoagulant effects for LDLT.

Stochastic resonance in brain activity elicited by auditory stimuli

We measured auditory steady state responses (ASSRs) in magnetoencephalogram to an ongoing sinusoidal amplitude modulated tone presented to the subject's left ear while bursts of white noise of various intensities were presented to the right ear. Because the power and coherence as functions of the noise to signal ratio differed considerably among subjects, we used their maximum values as test statistics for testing the group data. The results showed a significant enhancement in the phase coherence of ASSRs obtained over the right temporal regions by the presence of white noise of appropriate intensity. The observed stochastic resonance (SR) most likely occurred within the central nervous system. Our finding may be quite important as mechanisms of SR in biological systems are mostly unknown.

[Two cases of advanced hepatocellular carcinoma (HCC) effectively treated by oral UFT administration]

Case 1 was operated for HCC in September, 2002. After then TAE was performed two times for remnant liver recurrence. A year later, huge recurrence of left liver and tumor thrombus in IVC and PV were detected. After starting oral UFT administration, AFP lever went down within normal limit and tumor thrombus and early enhancement disappeared by CT scan. But after about a year, AFP level went up and TAE was performed two times, the patient died in July, 2007. Case 2 was operated for HCC in August, 2004. Re-operation was performed for recurrence of remnant liver in January, 2006. But recurrence was detected and TAE was performed in November. Ascites and leg edema appeared in June, 2007. Many recurrences of right liver, tumor thrombus in right hepatic vein and hilar hepatic lymph node were detected, UFT administration was started. After then, AFP level went down and tumor size reduced markedly by CT scan. We presents two cases effectively treated by oral UFT administration.

Primary colonic signet ring cell carcinoma presenting carcinocythemia: an autopsy case

Primary colorectal signet ring cell carcinoma (SRCC) is a rare but distinctive type of mucin-producing adenocarcinoma of the large intestine with still controversial clinicopathological features and prognosis. We encountered primary colonic SRCC in a 51-year-old Japanese man with extensive bone metastasis ultimately leading to carcinocythemia before the initiation of chemotherapy and surgical intervention. Three days before death, besides progressive disseminated intravascular coagulation that had been present on admission, hematological examination showed sudden leukocytosis with nonhematopoietic cells that subsequently turned out to be signet ring cells (SRCs). Carcinocythemia, the presence of circulating cancer cells in peripheral blood, is considered to be a rare but an ominous phenomenon occurring in the advanced stage of certain types of cancers, particularly mammary lobular carcinoma. It can be assumed that carcinoma cells lacking intercellular cohesiveness and polarized cell membrane organization, including SRCs as well as lobular carcinoma cells, can readily get access to the peripheral circulation; however, to our knowledge, this is the first report of primary colorectal SRCC that presented carcinocythemia. Extensive bone metastatic sites, in the present case, may have functioned as a reservoir of circulating SRCs.

Acoustic feedback system with digital signal processor to alert the subject and quantitative visualization of arousal reaction induced by the sound using dynamic characteristics of saccadic eye movement: a preliminary study

A new system has been developed to assess human alertness and to alert the subject with acoustic stimulation in accordance with the assessed level of alertness. Dynamic characteristics of saccadic eye movement (saccade: SC) were used to calculate an alertness index. Digital signal processor was adopted for the calculation. The system was tested through eye tracking tasks. The results indicated that the developed system could awaken the subject by feeding sound back to the subject. Also, arousal reaction induced by the sound was visualized quantitatively by analyzing values of the alertness index after the stimulation. These results indicate applicability of the system not only to awakening device for accident prevention, but also to a tool for investigating effects of the stimulation.

Relation between human alertness, velocity wave profile of saccade, and performance of visual activities

Practical method for assessing human alertness is desired for preventing traffic accidents caused by drowsiness in the drivers. We examined relation between saccade profile (PV/D), which was reported to have dependency on the alertness, and visual activities to investigate an applicability of the saccade for assessing the alertness in vision-dependent circumstances such as driving. We defined a new parameter of visual activity as "bit rate of visual perception (BRVP)", and analyzed relations of saccade velocity profile to the BRVP, relative pupil diameter, and critical fusion frequency. The results showed significant high positive correlations between PV/D, BRVP, and relative pupil diameter.

RELAXANT EFFECT OF ADRENOMEDULLIN ON BOVINE ISOLATED IRIS SPHINCTER MUSCLE UNDER RESTING CONDITIONS

1. The mechanisms involved in the fine adjustment of iris sphincter muscle tone are largely unknown. The aim of the present study was to clarify the effects of adrenomedullin on the resting tension of the bovine isolated iris sphincter muscle. 2. The motor activity of the bovine isolated iris sphincter muscle was measured isometrically. The effects of adrenomedullin on resting tension were analysed in the presence of indomethacin. The presence of adrenomedullin mRNA in the preparation was determined by reverse transcription-polymerase chain reaction. Immunolabelling for adrenomedullin was also performed. 3. Adrenomedullin significantly decreased the resting tension of the muscle. The relaxant effect of adrenomedullin was significantly inhibited by adrenomedullin (22-52), a putative antagonist for the adrenomedullin receptor, or calcitonin gene-related peptide (CGRP) (8-37), a putative antagonist for the CGRP1 receptor. The relaxant effect was almost completely blocked by a combination of adrenomedullin (22-52) and CGRP (8-37). 4. The relaxant effect of adrenomedullin was also significantly diminished by 2',5'-dideoxyadenosine, an inhibitor of adenylate cyclase, N(G)-nitro-L-arginine, an inhibitor of nitric oxide synthesis, or 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one, an inhibitor of soluble guanylate cyclase. 5. Reverse transcription-polymerase chain reaction analysis showed that adrenomedullin mRNA was expressed in the muscle strip. Immunopositive staining for adrenomedullin was detected in blood vessel cells and in the iris sphincter muscle cells. 6. These results suggest that adrenomedullin may be an autocrine and paracrine regulator of the resting tension of the iris sphincter muscle. Its biological effects may be due to the direct involvement of adrenomedullin receptors and also to the stimulation of CGRP1 receptors. The stimulation of these receptors by the peptide leads to the activation of adenylate cyclase and soluble guanylate cyclase and subsequent relaxation of the muscle strip.

Magnetic noise rejection in the MCG using independent component analysis

In magnetocardiogram (MCG) measurements, the magnetic noise from any magnetic wire, used to suture the sternum after heart surgery, becomes a problem. As one method of noise rejection, independent component analysis is seen here to be effective. In this study, MCG measurements were carried out under conditions where a wire was attached to a normal subject, also where no wire was attached. Signal processing by independent component analysis was carried out in order to reduce the effect of magnetic noise from the wire. From the comparison of the waveforms after this signal processing and the waveforms where the wire was not attached, it was apparent that the magnetic noise from the wire was reduced. Thus, we have shown that independent component analysis is effective for the reduction of magnetic noise from a magnetic wire, in MCG measurements.

Whole-head SQUID system in a superconducting magnetic shield

We have constructed a mobile whole-head SQUID system in a superconducting magnetic shield - a cylinder of high Tc superconductor BSCCO of 65 cm in diameter and 160 cm in length. We compared the noise spectra of several SQUID sensors of SNS Josephson junctions in the superconducting magnetic shield with those of the same SQUID sensors in a magnetically shielded room of Permalloy. The SQUID sensors in the superconducting magnetic shield are more than 100 times more sensitive than those in a magnetically shielded room of Permalloy below 1 Hz. We tested the whole-head SQUID system in the superconducting magnetic shield observing somatosensory signals evoked by stimulating the median nerve in the right wrist of patients by current pulses. We present data of 64 and 128 traces versus the common time axis for comparison. Most sensory responses of human brains phase out near 250 ms. However monotonic rhythms still remain even at longer latencies than 250 ms. The nodes of these rhythm are very narrow even at these longer latencies just indicating low noise characteristics of the SQUID system at low-frequencies. The current dipoles at the secondary somatosensory area SII are evoked at longer latencies than 250 ms contributing to a higher-level brain function. The SQUID system in a superconducting magnetic shield will also have advantages when it is used as a DC MEG to study very slow activities and function of the brain.

3-D magnetic measurement of neuromagnetic response of somatosensory area to different repetition frequencies

3-D magnetic measurements of the bilateral somatosensory evoked fields (SEFs) by electric stimulus to the right thumb for four normal subjects were carried out, using a three-dimensional (3-D) second-order gradiometer connected to 39-channel SQUIDs, which can detect magnetic field components perpendicular to the scalp (Br) and tangential to the scalp (Btheta, Bphi) simultaneously. To discuss the relationship between the phase lag and stimulus repetition frequency (SRF), the delay times of a component synchronous with the SRFs (1.99 to 27.02 Hz) were calculated by the convolution of the reference signal and the SEF wave (BPF: 15-40 Hz). The phase lag characteristic to the SRF in the contralateral hemisphere to the stimulus was linear in the ranges below 8 Hz and above 8 Hz in all magnetic components. The phase lag characteristic of the ipsilateral hemisphere to the stimulus was linear in only below-8 Hz in all components. It was tested for significance of the linear regression slope (beta not = 0, P<0.05).

3-D magnetic measurement of exercise-induced MCG

We carried out a three-dimensional (3-D) vector measurement of exercise-induced magnetocardiograms (MCGs) for normal subjects with a wooden and brass-based bicycle ergometer. MCGs were measured by a 3-D second-order gradiometer connected to 39-channel SQUIDs, which can detect magnetic field components perpendicular to the chest wall (Bz) and tangential to the chest wall (Bx, By) simultaneously. Time-frequency analysis was applied to rest times and exercise-induced MCG data. It was shown that the power spectrum of the ST segment was different between the rest times and exercise-induced MCG. Principal component analysis (PCA) was also applied to the result of time-frequency analysis and the time course of frequency for the ST segment was evaluated quantitatively. It found that dominant frequency of the ST segment in the rest time was ranged 5.5 to 6.5 Hz in all components. And it was clearly shown that the peak frequency of the exercise-induced MCG was shifted to 10.5 Hz compared to that of rest MCG.

A reconstruction method of surface morphology with genetic algorithms in the scanning electron microscope

A reconstruction method of surface morphology with genetic algorithms from a line scan in the scanning electron microscope (SEM) has been developed. This method is an application of genetic algorithms, which are search algorithms based on the mechanics of natural selection and genetics, to surface morphology in SEM. To reconstruct the microstructures of a specimen surface on a substrate, the system requires only a line scan taken by a conventional SEM. To deal with statistical fluctuations in the grey level of each pixel on the experimental line scan, the reduced chi-square distribution is used as the objective function and a scheme for minimizing the number of vertices in the reconstructed surface profile is adopted. The resolution in the Z-direction tends to be statistical and independent of the angle of the specimen surface.

Measurements of the quantities of particles accumulated in the lungs of workers

The human body is enveloped in weak (10-9 T) magnetic fields generated by magnetic particles accumulated in the lungs and other organs. We studied magnetic fields from the lungs (magnetopneumogram) in order to determine how they may be utilized in the early diagnosis of pneumonoconiosis and other diseases. The effects of these diseases have been positively correlated with the size of the magnetic particle deposits in the lungs. When we measured the relaxation effect and the secondary magnetization for smokers and non-smokers, we found there was a large difference in these characteristics between these groups.

Experimental study of the discrimination of two signal sources in the brain by three-dimensional vector magnetic field measurement of a magnetoencephalogram

To determine the possibility of discriminating multi-sources in the brain by 3D vector magnetic field measurement of a magnetoencephalogram (MEG), measurements were made of magnetic fields produced by two current dipoles implanted in a spherical head model. The 3D vector magnetic field measurements were made by using a 3D second-order gradiometer connected to three rf-SQUIDs, which can detect magnetic field components perpendicular to and tangential to the scalp. The MEG distribution measuring the magnetic field perpendicular to the scalp was not helpful in estimating the location and number of sources because of the lack of a dipole pattern. By referring to the MEG distribution measuring the magnetic field distribution tangential to the scalp, however, two current sources could be clearly discriminated in a spherical head model. It was found that this MEG distribution measuring tangential to the scalp could provide information on new constraint conditions for the calculation of inverse problems with multi-sources. These results were also confirmed by measurement of the mixed somatosensory evoked fields elicited by simultaneous electric stimulation to the median nerve and the thumb.

[A method on the filling of primary caries]

With advancement of materials and techniques for tooth restoration and changes in public awareness, procedures for treating primary caries have gradually minimized scraping of the tooth. In other words, there is a tendency toward qualitative transformation in caries prevention, moving from tertiary to secondary prevention, and further to primary prevention. The present paper describes a filling method for primary caries using an enamel cavity technique and Light-activated composite resin.

MATERIALS AND METHODS

1) Cleaning of the tooth surface with a polishing brush; 2) water rinsing and drying; 3) topical application of a caries detector; 4) moisture exclusion with a rubber dam, followed by scraping of the tooth with a carbide bur (#330; ISO, 008); 5) after scraping, removal of the carious lesion with a round bur (#1/2; ISO, 006); 6) formation of an enamel cavity in the adjacent pit and fissuer; 7) making of a bevel with a round diamond bur of 1.2mm in diameter; 8) etching; 9) water rinsing and drying; 10) application of bonding agent; 11) filling with Full-fil Compule and stepwise packing of the cavity, starting from a corner, with attention given to preventing bubbles; 12) make-up of the occlusal surface; 13) Polymerization with a polymerizing unit (Light activated); 14) occlusal equilibration; 15) margin correction with a trimming bur; 16) polishing.

[Clinical evaluation of ACDEMIN in the field of dentistry]

A clinical trial was performed to examine the effect of ACDEMIN, a combination of lysozyme chloride and vitamins (manufactured by Grelan Pharmaceutical Co., Ltd.,; supplied by Takeda Chemical Industries, Ltd.). The subjects were 65 patients with slight to moderate symptoms associated with locally developed diseases including gingivitis, periodontitis, pericoronitis of the wisdom tooth and gingival abscess. Improvement of the condition was evaluated according to symptom on the basis of local findings examined prior to and 7 days after administration. Adverse effects were also evaluated in terms of discomfort. General improvement was determined on the basis of improvement in symptoms and general safety on the basis of a comprehensive assessment of the adverse effects. The usefulness of the drug was determined on the basis of general improvement and general safety as assessed above. The results were as follows: 1) Of the 65 patients who entered the trial, 62 completed the course of administration. 2) The rates of improvement ("slightly improved" or better) according to symptom were 65.6% for gingival inflammation, 40.0% for bleeding, 50.0% for pus discharge, 41.8% for swelling, 61.9% for local pain, 26.7% for mouth odor, 21.7% for color tone and 62.3% for discomfort. 3) The rates of usefulness ("slightly useful" or better) according to disease were 66.7% for gingivitis, 92.0% for periodontitis, 81.8% for pericoronitis of the wisdom tooth and 100.0% for gingival abscess. 4) The usefulness of the drug was graded "very useful" in 4 patients, "fairly useful" in 18, "slightly useful" in 31 and "not useful" in none, with an overall rate of usefulness of 85.5% ("faily useful" or better). 5) No patients presented symptoms indicating an adverse effect.

[Clinical evaluation of the GaALAs laser treatment for hypersensitive dentin]

The methods available for treatment of hypersensitive dentin include the application of heavy metal salts such as diamine silver fluoride to the tooth, iontophoresis, Hyper-Band patching and restoration with various filling materials following cavity lining. Laser beam therapy, which has recently been used in dental treatment, is also expected to be applied to the treatment of hypersensitive dentin. In the present study, we obtained interesting results from the clinical use of a GaAlAs semiconductor Laser (Semilaser Nanox LX-800, GC Co.). The subjects were 63 patients with hypersensitive dentin: 8 patients without the exposed root, 40 with the exposed root, 21 treated with filling materials, 5 given Hyper-Band treatment, 14 with wedge-shaped defect, attrition or abrasion, and one with primary caries. Twenty-six fell into two or more categories. The effect of treatment was assessed by a single examiner in order to minimize error of estimates. Each lesion was directly irradiated for less than 3 minutes, and assessment of the result was conducted according to the criteria and method of Suzuki and Ishikawa. The results were as follows: The treatment was markedly effective in 44 (69.8%), effective in 12 (19.0%) and not effective in 7 (11.1%) of 63 patients. No case of exacerbation was found. The efficacy rate was 88.9%.

[Conscious survey of dental patients. 1. Questionnaire related to general dentistry (in the case of the new patients of the Nippon Dental University Hospital)]

Increased information on dentistry in the mass media in recent years may have caused changes in patients' attitudes toward dental care. To better understand patient' attitudes, we conducted a questionnaire survey of patients on the first visit to our hospital. Of 384 responses, 196 were eligible for statistical analysis. The following findings were obtained. 1. Among the motives for visiting a dental clinic, "Manifestation of pain or symptoms" was given by majority (85.7%) of respondents, followed by "detection of abnormality" (20.4%). The percentage of patients wanting treatment of "any part suggested by the dentist" was highest (35.7%), followed by those expecting "treatment including cleaning" (30.1%). The above results indicate that patients still tend to visit a clinical after subjective symptoms appear and leave the content of treatment to the dentist. However, an increasing number of patients appear to be concerned with their oral condition and visit a clinic before manifestation of symptoms. 2. Among factors in selecting their dentist, "expertise" obtained the highest percentage, 87.2%, followed by "providing prompt treatment" (38.8%) and "trying to avoid pain" (32.1%), in that order. Dissatisfaction with dentists was described as "no explanation of treatment" in 57.1%, "lack of sympathetic attitude" in 38.3% and "easily resorts to tooth extraction" in 35.4%. These results suggest that patients expect good human relations with their dentists, sufficient explanations of treatments and sympathetic consideration, as well as expertise. 3. The majority of patients (85.7%) hoped to receive instructions on oral hygiene and to be increased interest in information above prophylaxis. Meeting their needs will remain a future issue for dentists.

[Conscious survey of dental patients. 2. Questionnaire related to prevention (in the case of the new patients of the Nippon Dental University Hospital)]

A questionnaire on the consciousness of new patients was conducted in Nippon Dental University Hospital. Following our prior report, items regarding dental prevention were asked to 196 subjects in the present case. The results are as follows. 1. 53.1% of the subjects had experienced scaling of the teeth. However only 15.4% of them had regularly scaling. 2. 62.8% of the subjects had been given guidance in brushing and 39.8% of them had used toothbrushes by themselves in the guidance. 3. 99.5% of the subjects brushed their teeth everyday. 58.5% of them brushed twice a day. Regarding the brushing period, "3 minutes" amounded the highest radio, 33.3%. 4. Regarding the major purpose of brushing, "prevention of oral diseases" amounted to 50.5%, followed by "unknown". Namely, 23.0% of the subjects had no definite purpose of brushing. This figure suggests that the awareness on brushing was unexpectedly low. 5. 85.7% of the subjects wanted to have oral sanitation guidance and oral health management. Among them. 59.5% wanted to have "regular examination". To the question "How often can you visit our hospital except treatment?", 48.2% of the subjects answered "twice or more per year", 41.1% "a day for each examination" and 53.6% answered "60 minutes per day". Among those who wanted to have oral sanitation guidance and oral health management, only 32.7% wanted to participate in our oral sanitation class. These results indicate that many patients want to have passive management but for would start action by themselves. Thus it is the most important for dentists to carry out sufficient education and guidance under these situations.

[Bleaching of discolored teeth. Examination and evaluation of the effect of various bleaching agents]

Many patients suffer from tooth discoloration, a condition that produces more psychological distress than generally thought, especially when the anterior teeth are involused. In this study, tests were carried out to determine the effect of various agents applied discolored teeth for bleaching. Blood, colored tissue fluids I and II, attached to filter papers after being naturally exposed for a week were selected as object bleaching. Each subject was soaked in 30% hydrogen peroxide solution (30%H2O2), 3% hydrogen peroxide (3%H2O2), sodium hypochlorite solution (NaOCl), sodium perborate (NaBO3) and combination of them, then effect of agents were observed according to time-lapse. The following results were obtained. 1. NaOCl was most effective. 2. The action of 3%H2O2 was slow, showing only a slight bleaching effect after one week. 3. NaBO3 alone did not have any bleaching effect.

[Tooth discoloration possibly caused by medication (tetracycline)]

In this study, the following procedures to remove discoloration were performed, using a modified version of the Walking-Bleach method. 1) The stained dentin was removed as much as possible. 2) Effect of decolarion were enhanced by etching on the dentin. 3) After a desirable color was obtained, total etching and restoration with adhesive composite resin were conducted for strengthening and aesthetic recovery. Tooth discoloration due to tetracycline, 3 subjects in this study, has previously been regarded as difficult to bleach, could be carried out satisfactorily with few appointments. Consequently, this modification of the Walking-Bleach method was considered as one of effective methods.

Biomagnetism in Japan

The study of biomagnetic fields originating in a biological body is called biomagnetism. Among various fields of biomagnetism, this paper reviews the research and clinical works in magnetocardiogram, neuromagnetism, magneto-oculogram, magnetopneumogram and magnetic measurement for cell motility carried out in Japan.