Assessing the progression of chronic periodontitis using subgingival pathogen levels: a 24-month prospective multicenter cohort study.

BACKGROUND: The diagnosis of the progression of periodontitis presently depends on the use of clinical symptoms (such as attachment loss) and radiographic imaging. The aim of the multicenter study described here was to evaluate the diagnostic use of the bacterial content of subgingival plaque recovered from the deepest pockets in assessing disease progression in chronic periodontitis patients. METHODS: This study consisted of a 24-month investigation of a total of 163 patients with chronic periodontitis who received trimonthly follow-up care. Subgingival plaque from the deepest pockets was recovered and assessed for bacterial content of Porphyromonas gingivalis, Prevotella intermedia, and Aggregatibacter actinomycetemcomitans using the modified Invader PLUS assay. The corresponding serum IgG titers were measured using ELISA. Changes in clinical parameters were evaluated over the course of 24 months. The sensitivity, specificity, and prediction values were calculated and used to determine cutoff points for prediction of the progression of chronic periodontitis. RESULTS: Of the 124 individuals who completed the 24-month monitoring phase, 62 exhibited progression of periodontitis, whereas 62 demonstrated stable disease. The P. gingivalis counts of subgingival plaque from the deepest pockets was significantly associated with the progression of periodontitis (p < 0.001, positive predictive value = 0.708). CONCLUSIONS: The P. gingivalis counts of subgingival plaque from the deepest pockets may be associated with the progression of periodontitis.

Periodontal tissue engineering by nano beta-tricalcium phosphate scaffold and fibroblast growth factor-2 in one-wall infrabony defects of dogs.

BACKGROUND AND OBJECTIVE: Nanoparticle bioceramics are being investigated for biomedical applications. We fabricated a regenerative scaffold comprising type I collagen and beta-tricalcium phosphate (ß-TCP) nanoparticles. Fibroblast growth factor-2 (FGF-2) is a bioeffective signaling molecule that stimulates cell proliferation and wound healing. This study examined the effects, on bioactivity, of a nano-ß-TCP/collagen scaffold loaded with FGF-2, particularly on periodontal tissue wound healing. MATERIAL AND METHODS: Beta-tricalcium phosphate was pulverized into nanosize particles (84 nm) and was then dispersed. A nano-ß-TCP scaffold was prepared by coating the surface of a collagen scaffold with a nanosize ß-TCP dispersion. Scaffolds were characterized using scanning electron microscopy, compressive testing, cell seeding and rat subcutaneous implant testing. Then, nano-ß-TCP scaffold, nano-ß-TCP scaffold loaded with FGF-2 and noncoated collagen scaffold were implanted into a dog one-wall infrabony defect model. Histological observations were made at 10 d and 4 wk postsurgery. RESULTS: Scanning electron microscopy images show that TCP nanoparticles were attached to collagen fibers. The nano-ß-TCP scaffold showed higher compressive strength and cytocompatibility compared with the noncoated collagen scaffold. Rat subcutaneous implant tests showed that the DNA contents of infiltrating cells in the nano-ß-TCP scaffold and the FGF-2-loaded scaffold were approximately 2.8-fold and 3.7-fold greater, respectively, than in the collagen scaffold. Histological samples from the periodontal defect model showed about five-fold greater periodontal tissue repair following implantation of the nano-ß-TCP scaffold loaded with FGF-2 compared with the collagen scaffold. CONCLUSION: The ß-TCP nanoparticle coating strongly improved the collagen scaffold bioactivity. Nano-ß-TCP scaffolds containing FGF-2 are anticipated for use in periodontal tissue engineering.

Salivary pathogen and serum antibody to assess the progression of chronic periodontitis: a 24-mo prospective multicenter cohort study.

BACKGROUND AND OBJECTIVE: A diagnosis of periodontitis progression is presently limited to clinical parameters such as attachment loss and radiographic imaging. The aim of this multicenter study was to monitor disease progression in patients with chronic periodontitis during a 24-mo follow-up program and to evaluate the amount of bacteria in saliva and corresponding IgG titers in serum for determining the diagnostic usefulness of each in indicating disease progression and stability. MATERIAL AND METHODS: A total of 163 patients with chronic periodontitis who received trimonthly follow-up care were observed for 24 mo. The clinical parameters and salivary content of Porphyromonas gingivalis, Prevotella intermedia and Aggregatibacter actinomycetemcomitans were assessed using the modified Invader PLUS assay, and the corresponding serum IgG titers were measured using ELISA. The changes through 24 mo were analyzed using cut-off values calculated for each factor. One-way ANOVA or Fisher's exact test was used to perform between-group comparison for the data collected. Diagnostic values were calculated using Fisher's exact test. RESULTS: Of the 124 individuals who completed the 24-mo monitoring phase, 62 exhibited periodontitis progression, whereas 62 demonstrated stable disease. Seven patients withdrew because of acute periodontal abscess. The ratio of P. gingivalis to total bacteria and the combination of P. gingivalis counts and IgG titers against P. gingivalis were significantly related to the progression of periodontitis. The combination of P. gingivalis ratio and P. gingivalis IgG titers was significantly associated with the progression of periodontitis (p = 0.001, sensitivity = 0.339, specificity = 0.790). CONCLUSIONS: It is suggested that the combination of P. gingivalis ratio in saliva and serum IgG titers against P. gingivalis may be associated with the progression of periodontitis.

Bone augmentation using a highly porous PLGA/ß-TCP scaffold containing fibroblast growth factor-2.

BACKGROUND AND OBJECTIVE: Beta-tricalcium phosphate (ß-TCP), a bio-absorbable ceramic, facilitates bone conductivity. We constructed a highly porous three-dimensional scaffold, using ß-TCP, for bone tissue engineering and coated it with co-poly lactic acid/glycolic acid (PLGA) to improve the mechanical strength and biological performance. The aim of this study was to examine the effect of implantation of the PLGA/ß-TCP scaffold loaded with fibroblast growth factor-2 (FGF-2) on bone augmentation. MATERIAL AND METHODS: The ß-TCP scaffold was fabricated by the replica method using polyurethane foam, then coated with PLGA. The PLGA/ß-TCP scaffold was characterized by scanning electron miscroscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction, compressive testing, cell culture and a subcutaneous implant test. Subsequently, a bone-forming test was performed using 52 rats. The ß-TCP scaffold, PLGA-coated scaffold, and ß-TCP and PLGA-coated scaffolds loaded with FGF-2, were implanted into rat cranial bone. Histological observations were made at 10 and 35 d postsurgery. RESULTS: SEM and TEM observations showed a thin PLGA layer on the ß-TCP particles after coating. High porosity (> 90%) of the scaffold was exhibited after PLGA coating, and the compressive strength of the PLGA/ß-TCP scaffold was six-fold greater than that of the noncoated scaffold. Good biocompatibility of the PLGA/ß-TCP scaffold was found in the culture and implant tests. Histological samples obtained following implantation of PLGA/ß-TCP scaffold loaded with FGF-2 showed significant bone augmentation. CONCLUSION: The PLGA coating improved the mechanical strength of ß-TCP scaffolds while maintaining high porosity and tissue compatibility. PLGA/ß-TCP scaffolds, in combination with FGF-2, are bioeffective for bone augmentation.

Application of collagen hydrogel/sponge scaffold facilitates periodontal wound healing in class II furcation defects in beagle dogs.

BACKGROUND AND OBJECTIVE: A three-dimensional scaffold may play an important role in periodontal tissue engineering. We prepared bio-safe collagen hydrogel, which exhibits properties similar to those of native extracellular matrix. The aim of this study was to examine the effect of implantation of collagen hydrogel/sponge scaffold on periodontal wound healing in class II furcation defects in dogs. MATERIAL AND METHODS: The collagen hydrogel/sponge scaffold was prepared by injecting collagen hydrogel, cross-linked to the ascorbate-copper ion system, into a collagen sponge. Class II furcation defects (of 5 mm depth and 3 mm width) were surgically created in beagle dogs. The exposed root surface was planed and demineralized with EDTA. In the experimental group, the defect was filled with collagen hydrogel/sponge scaffold. In the control group, no implantation was performed. Histometric parameters were evaluated 2 and 4 wk after surgery. RESULTS: At 2 wk, the collagen hydrogel/sponge scaffold displayed high biocompatibility and biodegradability with numerous cells infiltrating the scaffold. In the experimental group, reconstruction of alveolar bone and cementum was frequently observed 4 wk after surgery. Periodontal ligament tissue was also re-established between alveolar bone and cementum. Volumes of new bone, new cementum and new periodontal ligament were significantly greater in the experimental group than in the control group. In addition, epithelial down-growth was suppressed by application of collagen hydrogel. CONCLUSION: The collagen hydrogel/sponge scaffold possessed high tissue compatibility and degradability. Implantation of the scaffold facilitated periodontal wound healing in class II furcation defects in beagle dogs.

Root surface conditioning with bone morphogenetic protein-2 facilitates cementum-like tissue deposition in beagle dogs.

BACKGROUND AND OBJECTIVE: Modification of the root surface may play an important role in regenerating the periodontal attachment between the root and periodontal connective tissue. We speculated that bone morphogenetic protein (BMP) application to the root surface constructed a novel attachment by cementum-like hard tissue, although gingival connective tissue proliferated to the root surface. The aim of this study was to examine whether BMP-2 guided cementum-like tissue deposition on a BMP-conditioned root surface. MATERIAL AND METHODS: Root dentin on the buccal side of 24 teeth in four beagle dogs was surgically exposed. The denuded root dentin surfaces were demineralized with EDTA and washed with saline. Subsequently, 15 microL of BMP-2 solution (loading dose, 0.4 and 1.0 microg/microL) was applied to the root dentin surface. In the control roots, phosphate-buffered saline was applied to the root surface. Specimens were analyzed histologically 16 wk after surgery. RESULTS: Formation of cementum-like tissue was frequently observed on the BMP-2-conditioned root at the coronal portion. Cellular cementum-like tissue was separated from the original cementum and encapsulated with gingival connective tissue. Cementum-like tissue formation with BMP-2 at 1.0 microg/microL was significantly greater than that in the control roots and those with BMP-2 at 0.4 microg/microL. Downgrowth of the junctional epithelium in the 1.0 microg/microL BMP-2 group was significantly less than that in the control roots. CONCLUSION: Root dentin surface conditioning with BMP-2 stimulated cementum-like tissue formation and inhibited epithelial downgrowth.

Application of self-efficacy theory in dental clinical practice.

In clinical practice, self-efficacy refers to how certain a patient feels about his or her ability to take the necessary action to improve the indicators and maintenance of health. It is assumed that the prognosis for patient behaviour can be improved by assessing the proficiency of their self-efficacy through providing psychoeducational instructions adapted for individual patients, and promoting behavioural change for self-care. Therefore, accurate assessment of self-efficacy is an important key in daily clinical preventive care. The previous research showed that the self-efficacy scale scores predicted patient behaviour in periodontal patients and mother's behaviour in paediatric dental practice. Self-efficacy belief is constructed from four principal sources of information: enactive mastery experience, vicarious experience, verbal persuasion, and physiological and affective states. Thus, self-efficacy can be enhanced by the intervention exploiting these sources. The previous studies revealed that behavioural interventions to enhance self-efficacy improved oral-care behaviour of patients. Therefore, assessment and enhancement of oral-care specific self-efficacy is important to promote behaviour modification in clinical dental practice. However, more researches are needed to evaluate the suitability of the intervention method.

Music before Dental Surgery Suppresses Sympathetic Activity Derived from Preoperative Anxiety: A Randomized Controlled Trial.

The aim of this study was to estimate the relieving effect of music intervention on preoperative anxiety by using heart rate variability (HRV) analysis. In this randomized controlled trial, 86 adult patients were scheduled to undergo impacted tooth extraction under intravenous sedation and local anesthesia and were classified as either fearful or nonfearful based on a questionnaire. Thereafter, the patients were subdivided into 2 groups: those who listened to music from the time that they arrived at the outpatient clinic until immediately before entering the operating room and those who did not listen to music. The effect of music intervention was evaluated by assessing 1) the low-frequency/high-frequency ratio of HRV, in which positive changes indicate increased sympathetic nervous activity, and 2) the coefficient of component variance for high frequency, in which positive changes indicate increased parasympathetic nervous activity, assessed by means of HRV analysis. Subjective preoperative anxiety was evaluated on a visual analog scale. For fearful patients, the mean magnitude of low-frequency/high frequency changes from baseline among those who listened to music was significantly lower as compared with those who did not listen to music (in the private room: -1.45 ± 1.88 vs. 1.05 ± 1.88, P = 0.0096, 95% confidence interval of effect size = -4.52 to -0.48, Cohen's d = -0.75; in the operating waiting room: -2.18 ± 2.39 vs. -0.10 ± 3.37, P = 0.011, 95% confidence interval of effect size = -3.94 to -0.22, Cohen's d = -0.71, respectively). Visual analog scale scores were also significantly different. Coefficient of component variance for high frequency and heart rate did not differ significantly between the 2 groups. From the perspective of autonomic nervous activity, music intervention is useful for relieving anxiety in patients with dental fear before they enter a dental outpatient operating room. Music intervention may relieve anxiety by reducing sympathetic nervous activity, while parasympathetic nervous activity is not involved (UMIN000016882). Knowledge Transfer Statement: The results of this study revealed that music intervention is useful for clinicians when planning preoperative anxiety management of patients with dental fear who undergo impacted tooth extraction under intravenous sedation and local anesthesia. As a bridging intervention, music intervention enables stress management to continue uninterrupted from the patient's arrival at the dental outpatient clinic to intravenous sedation until completion of the dental surgery. With consideration of cost-effectiveness, absence of adverse physical effects, immediate effect, safety in terms of not using drugs, and lack of concerns about recovery, this information could lead to more appropriate decisions regarding anxiety management in dentistry.

Healing in transplanted teeth with periodontal ligament cultured in vitro.

Regeneration of connective tissue attachment is the ultimate goal of periodontal therapy. It has been suggested that periodontal ligament cells possess the potential to create new connective tissue attachment. However, as cells from gingiva and alveolar bone occupy the root surface during initial wound healing, population by periodontal ligament cells is limited in vivo. We have been developing a new periodontal regeneration technique using in vitro tissue culture of periodontal ligament remaining on a periodontally involved root. The purpose of this study was to examine the periodontal healing after transplantation of teeth with reduced periodontal ligament that had been cultured in vitro. Twenty-five incisors from four beagles were used. After the teeth were extracted, the periodontal ligament and cementum were removed from coronal part of the roots and the roots were planed. The periodontal ligament of the apical part was retained. Fourteen teeth of the experimental group were transplanted following culture for 6 weeks. Eleven teeth of the control group were similarly prepared and immediately transplanted without tissue culture. Four weeks after transplantation, the specimens were prepared for histological analysis. Downgrowth of junctional epithelium on the root of experimental group was significantly less than control. Most of the root planed surfaces of experimental group were covered with periodontal ligament fibers oriented parallel or inclined to the root surfaces and limited new cementum formation was observed near the apical end of the planed root. There was no significant difference between groups in observations on the root surface with remaining periodontal ligament. From the above results, it was concluded that periodontal tissue culture of teeth with root planed surface and remaining periodontal ligament could reduce the extent of epithelium downgrowth and increase connective tissue adhesion on the root planed surface, as well as minimize damage to remaining periodontal ligament, after transplantation of teeth.

Molecular cloning and expression of a major surface protein (the 75-kDa protein) of Porphyromonas (Bacteroides) gingivalis in Escherichia coli.

A major immunodominant surface protein (the 75-kDa protein) of Porphyromonas (Bacteroides) gingivalis 381 has been purified and its amino-terminal amino acid sequence has been determined. Using oligonucleotide probes corresponding to the sequence, we identified a recombinant plasmid clone carrying a single 4.2-kb BamHI fragment from pUC19 libraries of P. gingivalis. The BamHI fragment transferred to the bacteriophage T7 RNA polymerase/promoter expression vector system produced a slightly larger (77-kDa) protein, a precursor form, immunoreactive to the antibody against the 75-kDa protein, suggesting that the cloned DNA fragment probably carried an entire gene for the 75-kDa protein. Genomic Southern analysis revealed a single copy of the 75-kDa protein gene per genome among all P. gingivalis strains tested, and that no homologous genes are present in other black-pigmented Bacteroides species. These observations suggest that the 75-kDa protein gene may be useful as a specific DNA probe to classify or to detect this organism.

The concentration of lipopolysaccharide on individual root surfaces at varying times following in vivo root planing.

Material with endotoxin activity has been detected in extracts prepared from pooled, periodontally involved teeth, and it has been shown that root planing in vivo reduces the level of such material. However, questions concerning the concentration of endotoxin on the diseased surfaces of individual teeth and questions concerning how rapidly individual root planed tooth surfaces retoxify in vivo have not been addressed previously. Citric acid extracts were prepared from individual, periodontally diseased teeth that had been extracted either from the oral cavity without prior root planing or at varying times up to 12 weeks following root planing. Using a chromogenic Limulus Amebocyte Lysate (LAL) assay, we were able to quantitate the amount of endotoxin associated with diseased root surfaces of individual teeth. We concluded that the extracted material contained endotoxin since it activated LAL and since the LAL-activation was heat-stable, acid-stable and neutralizeable by polymyxin B. The levels of endotoxin found on the root surfaces of these individual, periodontally involved teeth at varying times following in vivo root planing support the following conclusions: the concentration of endotoxin present on diseased root surfaces is markedly reduced, but not eliminated, by in vivo root planing, significant retoxification of root planed surfaces occurs within a relatively short time period after root planing and biological responses to such toxification conceivably may lead to subsequent phases having reduced levels of endotoxin.

Microscopic polyangiitis that presented liver dysfunction prior to noted renal manifestations.

In microscopic polyangiitis (MPA), renal manifestations are very common as first symptoms. Here, we report a case of MPA which presented liver dysfunction prior to noted renal manifestations. A 58-year-old woman was hospitalized because of a fever for 8 weeks. A laboratory examination revealed marked elevation of alkaline phosphatase and gamma-glutamyl transpeptidase, while blood urea nitrogen and creatinine levels remained normal. Although apparent renal dysfunction developed in this case soon after hospitalization, physicians should be aware of the variety of clinical manifestations in MPA. Moreover, antineutrophil cytoplasmic autoantibodies were found to be helpful for diagnosing MPA.

Churg-Strauss syndrome with pachymeningitis refractory to steroid therapy atone--a case report.

Churg-Strauss syndrome (CSS) is a rare syndrome of unknown cause, which is characterized by bronchial asthma and hypereosinophilia followed by systemic symptoms of angiitis. In 1951, Churg and Strauss first distinguished this disease from periarteritis nodosa. Our patient in particular was also complicated with otorhinological symptoms, which have less frequently been reported in CSS cases. We have detailed her clinical symptoms.

[Chronic neutrophilic leukemia associated with monoclonal gammopathy (IgA, kappa type)].

A 62-year-old woman with chronic neutrophilic leukemia (CNL) is described. She presented in February 1988 for evaluation of leukocytosis of 3 years' duration with no complaint. Physical examination was normal. The leukocyte count was 20,100/microliters with 70% segmented neutrophils and 12% band forms. A myelogram showed marked myeloid hyperplasia and plasmacytosis (5.9%). Neutrophil alkaline phosphatase score, serum lysozyme and vitamin B12 levels were elevated. Cytogenetic analysis of the marrow aspirate showed normal karyotype, with no Philadelphia chromosome. Total serum protein (TP) was 7.5 g/dl with increased beta-globulin (23.5%), identified as monoclonal IgA kappa (3.3 g/dl) on immunoelectrophoresis. No activity of G-CSF was detected in the serum. A retrospective study revealed that the beta-globulin level was normal (6.3%, TP 6.9 g/dl) in 1980 and that it was slightly increased (11.6%, TP 7.0 g/dl) without leukocytosis (5,900/microliter) in 1981. In 1985, when leukocytosis obviously existed (9,900/microliter), the percentage of beta-globulin was increased to 17.5% (TP 7.2 g/dl). The possibility that monoclonal gammopathy preceded the leukocytosis must be admitted. On the basis of our observation, it is assumed that CNL and monoclonal gammopathy may be blood dyscrasias derived from a common precursor cell or that the immunological abnormality associated with monoclonal gammopathy may be implicated in the development of CNL.

[Appropriate lymph node dissection in thyroid adenocarcinoma].

Thirty-four patients underwent thyroid surgery for papillary and follicular adenocarcinomas in the period from 1985 to 1989. Fourteen patients were treated with local neck dissection and 20 patients, with modified or radical neck dissection. Cervical lymph node metastasis was found in 25 patients (74%). Our recent policy for lymph node dissection is as follows: When deep cervical lymph node metastasis is clinically demonstrated, radical or modified neck dissection is performed. In patients without clinically demonstrated metastasis, local neck dissection and sampling of the internal jugular chain are performed. When microscopic metastasis is found in frozen sections, modified neck dissection is added. Thus we could select patients for modified neck dissection and choose appropriate neck dissection for more complete cancer clearance without losing postoperative functions.

[Evoked oto-acoustic emissions in patients with secretory otitis media].

In many studies, Evoked Otoacoustic Emissions (EOAEs) have been routinely documented in subjects with normal middle ear function showing tympanogram (TG) A type. However, middle ear dysfunction may influence the measurements of EOAEs. We investigated the EOAEs in ears with secretory otitis media (SOM) in order to understand the effects of middle ear dysfunction on EOAE measurements. We present data from 73 SOM ears of 38 subjects aged 3 to 58 (mean = 9.4 years) and data from 61 ears of 54 subjects with sensorineural hearing loss as a control. Generally, the EOAE thresholds of ears with mild sensorineural hearing loss have a good correlation with the audiometric hearing threshold level. On the other hand, the EOAE thresholds of ears with SOM were on the average higher than those expected from the audiometric hearing threshold level. In this paper, we classified TG B type further into TG B1 type and TG B2 type according to our criteria. Though neither TG B1 type nor TG B2 type revealed peaks in the tympanogram (-300mmH2O < or = < or = 200mmH2O), the 2 groups differ in that TG B1 type seems to have its peak at pressures under -300mmH2O on tympanography while TG B2 type seems to have no peaks in that pressure range. As a consequence of this classification, most of the EOAE thresholds of SOM ears showing TG B2 type were scaled out (> or = 40 or 50 dB nHL).(ABSTRACT TRUNCATED AT 250 WORDS)

[Changes in human spontaneous otoacoustic emissions with contralateral acoustic stimulation].

According to current cochlear concepts, spontaneous otoacoustic emissions (SOAEs) are thought to be the product of outer hair cell (OHCs) movement. Furthermore, efferent neurofibers from the olivocochlear bundle primarily innervate OHCs. Thus, we designed this investigation to determine changes in SOAE under conditions of contralateral acoustic stimulation. Fouty-two normal ears of 34 subjects with uni- or bilateral SOAEs were examined. The sound pressure level (SPL) of SOAE was measured 3 times in each subject and was initially averaged. The white noises of 30 or 40dBSPL, believed not to affect the other side, were then loaded contralaterally and the SPL of SOAEs were measured and compared with the non-loaded data. The SPL of single SOAEs were actually suppressed with 40dBSPL stimulation while the SPL of multiple SOAEs showed typical changes. Interestingly, no significant suppression of SOAEs was noticed under conditions of contralateral acoustic stimulation of the impaired ear. These data suggest that contralateral acoustic stimulation could affect OHC function via the olivocochlear bundle.

[Otoacoustic emissions of full-term and preterm neonates].

Transiently evoked otoacoustic emission (TEOAE), distortion product otoacoustic emission (DPOAE), and spontaneous otoacoustic emission (SOAE) were measured in 45 full-term neonates (68 ears) and 12 preterm neonates (20 ears) with ILO88 & 92. Measurements were performed in the nursery of the obstetrics ward or NICU (not sound proof room) under natural sleeping condition after nursing. No sedating agent was used. TEOAEs were rated "good response" in 61 (89.7%) of 68 full-term neonate ears. DPOAEs were rated "good response" in 40 (71.4%) of 56 full-term neonate ears. SOAEs were detectable in 25 (62.5%) of 40 full-term neonate ears. Considering the high positive rate of TEOAE in full-term neonates and the easy and noninvasive method of measurement, we concluded that TEOAE is useful for auditory screening in neonates. There was failure to detect TEOAEs in 7 ears and the measurements were all performed within 6 days after birth. Some reports claim that residual amnion in the external auditory canal or the middle ear in the first few days after birth causes slight hearing loss. Thus, we expected that making the measurements more than 7 days after birth might yield higher "good response" rates. We sometimes found that the Total Echo Powers of TEOAEs were reduced by the poor condition of the ear probe. Thus, we must be very careful in regard to this technical problem in order to perform accurate examinations. Because of its lower "good response" rate, DPOAE was not as useful for screening as TEOAE. Because of the movements or respiratory noises of the newborn infants, it was hard to detect reliable DPOAEs, particularly in the low frequency range. On the other hand, because of its frequency specificity, particurally at high frequencies, DPOAE will be useful for detecting the partial hearing impairment such as congenital high-tone hearing impairment. It would be difficult to use SOAE as a clinical test. Because it is not an evoked response, its mechanism of generation is not well understood. We expect that following longitudinal changes in SOAE in neonates may yield some information about it. We measured mainly TEOAE in preterm neonates because we had to complete the measurements as soon as possible. High Total Echo Powers of TEOAEs were recorded in most infants over 38 weeks of PCA (post conceptional age). The earliest case showed reliable TEOAE at 35 weeks PCA. In most cases that could be measured twice on different days, the Total Echo Powers of TEOAE, were higher in the second time. We therefore concluded that TEOAE might serve as an examination for monitoring the maturation of preterm neonate hearing.

[Relationship between distortion product otoacoustic emissions and pure tone thresholds in normal and hearing-impaired ears].

To establish clinical criteria for distortion product otoacoustic emissions (DPOAEs) in order to distinguish normal-hearing from hearing-impaired ears, DPOAEs were measured and evaluated in 325 normal and 291 cochlear-impaired human ears using an ILO92 Otoacoustic Emission Analyzer. The background noise level was too variational in each individual ear to ignore in DPOAE measurements. Therefore, the value of the difference between the DPOAE amplitude and the background noise level (DPOAE noise) was calculated and compared with the pure tone threshold at 1 kHz, 2 kHz and 4 kHz. It was difficult, however, to precisely separate normal-hearing and hearing impaired ears with DPOAE noise values because many normal ears presented small amplitudes of DPOAEs and some impaired ears showed high amplitudes. Therefore, cumulative distributions of sensitivity (normal hearing ears identified as normal hearing) and specificity (hearing impaired ears identified as hearing impaired) were constructed and used to calculate a cut off point for DPOAE-noise in order to separate normal hearing from hearing impaired ears. It is considered that the cut-off points (DPOAE noise values of 7.3 dB at 1 kHz, 10.3 dB at 2 kHz and 16.1 dB at 4 kHz) at which the false alarm rates (1 specificity: the rate of hearing impaired ears incorrectly identified as normal hearing) correspond to 5% can be useful for clinical evaluation of DPOAEs.

[Idiopathic enlargement of the right atrium with persistent superior vena cava].

A 69-year-old male, who had been found (during a routine roentgenogram of the chest at an annual check-up) to have cardiomegaly, had been asymptomatic until 63 years of age, when DOE and swelling of the legs appeared. He visited our hospital because these symptoms has become more severe. Physical examination revealed JVD, third heart sound and a grade 3 holosystolic murmur, hepatomegaly and edema in the lower legs. His ECG showed atrial fibrillation. His chest X-P showed marked cardiomegaly and rt pleural effusion. His echocardiography and MRI revealed a marked enlargement of the right atrium and a slight enlargement of the right ventricle. The latter also showed persistent left superior vena cava. The cardiac catheterization, angiocardiography and intracavitary electrocardiography revealed no organic cardiac disease which induced enlargement of the right atrium. The idiopathic enlargement of the right atrium is a rare disease. Patients suffering from this disease are asymptomatic in most cases. We reported the idiopathic enlargement of the right atrium with persistent left superior vena cava in this paper.