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A Homma

Publications and source records attributed to A Homma.

At least 19 recordsLinked to original sources
PubMed2003

Measurement of the neutron detection sensitivity of a liquid in metastable states.

A device able to trap a liquid droplet in a host liquid in a metastable (superheated) state was developed for a better understanding of the operational principles and for an extension of the application of superheated drop detectors (SDDs). Droplets of trans-2-butene in a metastable state were exposed to Am-Be neutrons and evaporation of the droplets was observed. By measuring lifetime distributions of irradiated droplets, neutron sensitivities were derived from the distributions. The sensitivities were compared with calculations and experiments performed by using superheated emulsions. Results are discussed related to the model of radiation induced vaporisation on which the operational principles of superheated emulsions were based. The experiments in this study showed that the device developed could be applied to measure radiation sensitivities of different kinds of liquids for different kinds of radiations without any special detector preparation.

Alkenes↗
PubMed2001

Correlation of clinicopathological parameters and biological markers related to apoptosis and proliferative activity with a clinical outcome in squamous cell carcinoma of the larynx treated with concurrent chemoradiotherapy.

OBJECTIVE: This study was designed to determine whether biological markers related to apoptosis or proliferative activity are associated with the clinical outcome in patients with squamous cell carcinoma (SCC) of the larynx treated with concurrent chemoradiotherapy. METHODS: Immunostaining with antibodies specific to p53, bcl-2, bax, and MIB-1 was performed to evaluate expression of these proteins in formalin-fixed, paraffin-embedded specimens of 59 patients treated with concurrent chemoradiotherapy (carboplatin, 100 mg/m2, four to six times every week; total radiation dose of 40-65 Gy over 4-6.5 weeks). RESULTS: Multivariate analysis indicated that nodal status was a significant indicator of overall survival (OS: P = 0.001). Patients with bcl-2 positive tumors had better OS than those with bcl-2 negative tumors in both univariate (P = 0.002) and multivariate analyses (P < 0.001 ). In the univariate analysis, a considerable difference in OS was observed among the expressions of bax (P = 0.077), MIB-1 proteins (P = 0.071). and OS. but the difference was not statistically significant. CONCLUSION: This study indicates that nodal status is the major prognostic tactor in patients with SCC of the larynx treated with concurrent chemoradiotherapy. These results provide useful information for predicting prognosis. Further analysis of biological factors is needed to evaluate the value as predictive markers.

Apoptosis↗
PubMed2001

Clinical study of adenoid cystic carcinoma of the head and neck.

OBJECTIVE: We examined prognostic factors and outcome of the primary treatment in patients with adenoid cystic carcinoma (ACC) of the head and neck. METHODS: Twenty patients with ACC of the head and neck who had been treated in our institution from 1985 to 1998 were enrolled in this study. Disease-specific survival rate was analyzed by the Kaplan-Mejer method, and the log-rank test was applied to compare the survival rates. RESULTS: The overall 5- and 10-year survival rates determined by Kaplan-Meier analysis were 81 and 57%, respectively. Patients with major salivary gland ACC obtained the best 10-year survival rate (83%), while those with paranasal sinus ACC had the worst survival rate (33%). Predominance of the solid component on pathological examination might indicate a worse prognosis. Our study revealed that postoperative radiotherapy could yield better control of the lesion focus. Chemotherapy failed in some patients and was not dramatically effective by itself. CONCLUSIONS: The long-term prognosis of ACC was poor. Long-term follow-up is necessary for better prognosis of patients treated with radical treatment regimens.

Adult↗
PubMed2001

Concurrent chemotherapy and radiotherapy as initial treatment for stage II supraglottic squamous cell carcinoma.

OBJECTIVE: To evaluate the efficacy and safety of concurrent carboplatin (CBDCA) and radiotherapy for laryngeal carcinoma. we investigated survival rates and laryngeal preservation rates in patients with this treatment modality and those with radiation therapy only. METHODS: We underwent chemotherapy with CBDCA and conventional radiotherapy concurrently to 17 patients with untreated stage II (T2NOM0) supraglottic squamous cell carcinoma since November 1990. CBDCA (100 mg/m2) was administered intravenously once a week concurrently with radiotherapy (2.5 Gy/fr, 4 times a week). At the dose of 40 Gy, the results were evaluated, and some of the patients underwent planned surgery and others continued the radiotherapy up to 65 Gy. RESULTS: Overall 5-year survival rate by Kaplan-Meier method was 81.1%. Actual laryngeal preservation rate was 76.0%. Toxicity over grade III was noticed in two patients. Compared with 14 cases of historical controls, which were treated by radiation therapy alone between 1988 and 1990, the cases with concurrent radiotherapy and chemotherapy had statistically significant advantage in overall successful laryngeal preservation rate (P < 0.05), whereas the two groups were not significantly different in the overall 5-year survival rate.

Aged↗
PubMed2001

A study of piriform sinus fistula cases.

We have experienced five cases of piriform sinus fistula for the last 10 years. It is a relatively rare disease, and partly because of poor understanding of the disease, in one case infection had repeatedly recurred without being adequately treated for over 20 years, and in most cases there was a long time lapse before the diagnosis. In another case, it was difficult to image the fistula with contrast medium and fistulectomy was performed without identifying it on imaging. We have applied various devices to those cases where imaging of fistula was difficult, and achieved complete resection of fistula and have not observed recurrences of infection after resection.

Adult↗
PubMed2001

A clinical study on the cervical lymph node metastasis of maxillary sinus carcinoma.

OBJECTIVE: To improve the management of maxillary sinus carcinoma, we retrospectively investigated the significance of cervical lymph node metastasis in our treated cases and discussed how to deal with the cervical lymph node metastasis as a prognostic factor. METHODS: Medical records of 118 patients with maxillary sinus carcinoma diagnosed and treated in our institute from 1982 to 1997 were retrospectively reviewed. Tumors were staged according to UICC classification 1987. The cumulative survival was analyzed by the Kaplan-Meier method. Generally, the patients had undergone preoperative radiotherapy and surgery. We examined the cervical lymph node metastasis detected at the first examination and the subsequent cervical lymph node metastasis in relation to the prognoses. RESULTS: The incidence of cervical lymph node metastasis at the initial diagnosis was 7.9% (n = 9), and that of secondary cervical lymph node metastasis without recurrence at the primary site after the first treatment was 8.3% (n = 9). In most cases, we observed metastasis to the lymph nodes in the submandibular region and in the jugular chain. The result of treatment of cervical lymph node metastasis was grave. Among the patients with cervical lymph node metastasis detected at the first examination, four patients developed local recurrence and three patients developed distant metastasis. On the other hand, among those with secondary cervical metastasis, three patients developed neck recurrence and three patients developed distant metastasis, but no local recurrence. CONCLUSIONS: In the cervical metastasis of maxillary sinus carcinoma, it is important to treat the primary lesion completely. In addition to it. we should control cervical metastasis and careful neck dissection is required. For the patients with cervical lymph node metastasis, it is necessary to consider the further treatment of distant metastasis.

Adult↗
PubMed2001

Pulmonary artery systolic pressures estimated by echocardiogram vs cardiac catheterization in patients awaiting lung transplantation.

BACKGROUND: At many lung transplant centers, right heart catheterization and transthoracic echocardiogram are part of the routine pre-transplant evaluation to measure pulmonary pressures. Because decisions regarding single vs bilateral lung transplant procedures and the need for cardiopulmonary bypass are often made based on pulmonary artery systolic pressures, we sought to examine the relationship between estimated and measured pulmonary artery systolic pressures using echocardiogram and catheterization, respectively. METHODS: We retrospectively reviewed all patients in our program who had measured pulmonary hypertension (n = 57). Patients with both echocardiogram-estimated and catheterization-measured pulmonary artery systolic pressures performed within 2 weeks of each other were included (n = 19). We analyzed results for correlation and linear regression in the entire group and in the patients with primary pulmonary hypertension (n = 8) and pulmonary fibrosis (n = 8). RESULTS: In patients with primary pulmonary hypertension, pulmonary artery systolic pressure was 94 +/- 27 and 95 +/- 15 mm Hg by echocardiogram and catheterization, respectively, with r(2) = 0.11; in patients with pulmonary fibrosis, 57 +/- 23 and 58 +/- 12 mm Hg with r(2) = 0.22; and in the whole group, 76 +/- 29 and 75 +/- 23 mm Hg with r(2) = 0.50. Thirty-two additional patients had mean pulmonary artery systolic pressure = 48 +/- 16 mm Hg by catheterization but either had no evidence of tricuspid regurgitation by echocardiogram (n = 22) or the pulmonary artery systolic pressure could not be measured (n = 10). CONCLUSIONS: In patients with pulmonary hypertension awaiting transplant, pulmonary artery systolic pressures estimated by echocardiogram correspond but do not serve as an accurate predictive model of pulmonary artery systolic pressures measured by catheterization. Technical limitations of the echocardiogram in this patient population often preclude estimating pulmonary artery systolic pressure.

Adult↗
PubMed2001

Cognitive functioning in centenarians: a coordinated analysis of results from three countries.

Cognitive functions among centenarians in Japan, Sweden, and the United States are described. Three areas are explored. First, definitions and prevalence of dementia are compared between Japan and SWEDEN: Second, levels of cognitive performances between centenarians and younger age groups are presented. Third, interindividual variations in cognitive performances in centenarians and younger persons are compared in Sweden and the United STATES: The Swedish and Japanese studies show a variation in prevalence of dementia between 40% and 63% with a relatively higher prevalence among women. Part of the variance is probably due to differences in sampling and criteria of dementia. Along with the lower cognitive performance in centenarians, compared with younger age groups, the Swedish and U.S. results show a wider range of performance among centenarians for those semantic or experientially related abilities that tend to be maintained over the adult life span. In contrast, a smaller range of performance is found for centenarians on those fluid or process-related abilities that have shown a downward age-related trajectory of performance. Lower variability is probably due to centenarians reaching the lower performance limit. The conclusions agree with the assumption of a general increase in cognitive differentiation with increasing age, primarily in measures of crystallized intelligence. The conclusions point to the general robustness of results across countries, as well as to the relative importance of cognition for longevity.

Age Distribution↗
PubMed2001

Donepezil for Alzheimer's disease: pharmacodynamic, pharmacokinetic, and clinical profiles.

Donepezil was developed in order to overcome the disadvantages of physostigmine and tacrine. Its use is based on the cholinergic hypothesis. Donepezil is a piperidine-based, reversible acetylcholinesterase inhibitor, that is chemically unrelated to other cholinesterase inhibitors. It was developed for the symptomatic treatment of Alzheimer's disease (AD). Donepezil is highly selective for acetylcholinesterase with a significantly lower affinity for butyrylcholinesterase, which is present predominantly in the periphery. Phase I and II clinical trials demonstrated donepezil's favorable pharmacokinetic, pharmacodynamic and safety profile. There is no need to modify the dose of donepezil in the elderly or in patients with renal and hepatic failure. Pivotal phase-III trials in the US, European countries, and Japan showed that donepezil significantly improved cognition and global function in patients with mild to moderate AD. In long-term trials, donepezil maintained cognitive and global function for up to 1 year prior to the resumption of gradual deterioration. Donepezil is generally well tolerated; most of its adverse events are mild, transient and cholinergic in nature. Donepezil produces no clinically significant changes in laboratory parameters, including liver function. The drug is approved for the treatment of mild to moderate Alzheimer's disease, but donepezil therapy does not have to be discontinued if a patient continues to deteriorate. Possible new indications for donepezil in psychiatric and neurologic diseases, other than AD, include dementia with Lewy bodies, brain injury, attention deficit hyperactivity, multiple sclerosis, Down's syndrome, delirium, mood disorders, Huntington's disease and sleep disorders.

Alzheimer Disease↗
PubMed2000

Bronchiolitis obliterans.

Bronchiolitis obliterans (BO) is a fibrotic lung disease involving the small conducting airways. BO may be classified by etiology and underlying disease or, more commonly, by histopathological pattern. The two major histopathological categories are (1) BO organizing pneumonia (BOOP) and proliferative bronchiolitis and (2) constrictive bronchiolitis. The former is often idiopathic in nature and may also be associated with connective tissue diseases and inhalation injury. Characteristic findings on chest imaging include alveolar infiltrates and ground glass opacities and pulmonary function tests (PFTs) usually reveal restrictive dysfunction. Constrictive bronchiolitis is associated with organ transplantation, infections, connective tissue diseases, inhalation injury, and drugs and may also have an idiopathic origin. The radiographic characteristic is a mosaic pattern on high-resolution computed tomography (HRCT) and PFTs most often reveal obstructive dysfunction. This article will attempt to review constrictive BO, including histopathology, clinical presentation, radiographic appearance, and physiological findings, for both idiopathic diseases, as well as specific clinical-associated entities.

Journal Article↗
PubMed2000

Current status of clinical trials for Alzheimer-type dementia in Japan: strategies to facilitate the development of antidementia drugs.

Several antidementia drugs are currently being developed in Japan. However, although the clinical trial period is one of the most important factors in drug development, it is not always possible to recruit a sufficient number of eligible patients in each facility for two reasons. One is related to the skill of investigators who are requested to undertake the trial, and another is related to the clinical trial system itself. The author outlines the current status of the development of acetylcholinesterase inhibitors as antidementia drugs and discuss the strategies to facilitate the development of antidementia drugs in Japan.

Alzheimer Disease↗
PubMed1999

Pulmonary evaluation and prevalence of non-invasive ventilation in patients with amyotrophic lateral sclerosis: a multicenter survey and proposal of a pulmonary protocol.

In order to evaluate the current standard of care for the management of respiratory failure in patients with amyotrophic lateral sclerosis (ALS), a questionaire was mailed to the Medical Directors of 48 multidisciplinary ALS centers in the United States. Twenty centers reported information on 2357 patients, mean of 124 patients per center. Pulmonary function tests were performed at each visit in 17/20 institutions. Arterial blood gases, maximal expiratory pressures and maximal inspiratory pressures were followed in three centers and serum chloride was monitored in only four centers. The use of non-invasive ventilation (NIV) was extremely variable (range 0-50%) and included 360 patients (15%). The majority of centers used symptoms/signs of hypoventilation and worsening forced vital capacity (FVC) to initiate NIV with no established protocol. A FVC between 20 and 40% was used by most centers to initiate NIV. Due to great variability in the approach to monitoring pulmonary function among ALS centers and the modest effects of current medications to slow disease progression, we propose the use of a structured protocol which can prospectively study the role of NIV in prolonging survival and improving quality of life.

Amyotrophic Lateral Sclerosis↗
PubMed1999

[Analysis of outcome of free jejunal-autograft for head and neck reconstruction--postoperative complications and functional results of swallowing in 49 cases].

We evaluated postoperative results in 49 patients (39 men, 10 women) who underwent pharyngoesophageal reconstruction with free-jejunal autograft following total pharyngolaryngoesophagectomy in the Department of Otolaryngology, Hokkaido University School of Medicine from 1989 to 1997. Evaluation was performed regarding the following points: 1) postoperative complications, 2) factors that determine the functional results of swallowing, 3) relation between forms of jejunal anastomosis and swallowing. The primary malignancy site was hypopharynx (39), cervical esophagus (4), larynx (3), thyroid (2) and trachea (1), Reconstructions were made with free jejunal autograft alone in 45 cases and with free jejunum in combination with gastric pull-up in 4. In patients who underwent reconstruction with jejunum alone, the anastomosis of the jejunum to the pharynx was performed in side-to-end fashion in 22, end-to-end in 18 and rho-shaped in 4. In the 1 remaining case, we used jejunal-patch graft. Postoperative complications including minor or nongraft related, occurred in 24 of 49 (49.0%) patients. Among these, graft-related complications were graft failure in 1 (2.0%), fistula formation in 3 (6.1%) and graft stricture in 2 (4.0%). Re-operations were required in one case of graft failure and 2 of fistula formation. Consequently, the overall graft-survival rate was 98.0% (48/49). Therefore, we considered the method of reconstruction to be a reliable procedure with a high-success rate. The swallowing function after reconstructive surgery was studied in 35 patients who underwent side-to-end (18) and end-to-end (17) anastomosis of the jejunum to the pharynx. We indicated that appropriate tension in the jejunum was the most important factor for adequate swallowing function. The end-to-end group had a higher rate of taking normal diet compared with the side-to-end group. The rate of swallowing dysfunction was only 5.9% (1/17) in the end-to-end group. On the other hand, 4 of 18 (22.2%) cases in the side-to-end group were regarded as having poor swallowing function. As a result we considered the end-to-end proximal jejunal anastomosis to be the more desirable form.

Adult↗
PubMed1999

Prognostic significance of clinical parameters and biological markers in patients with squamous cell carcinoma of the head and neck treated with concurrent chemoradiotherapy.

Concurrent chemoradiotherapy is reported to have a fair clinical outcome with organ preservation for patients with squamous cell carcinoma of the head and neck (SCCHN). The aim of this study was to determine whether biological markers are related to proliferative activity or apoptosis of tumor cells and whether clinical factors are associated with a clinical outcome in SCCHN patients treated with concurrent chemoradiotherapy. Immunostaining with antibodies specific for p53, bcl-2, bax, and MIB-1 was performed to evaluate expression of these proteins in formalin-fixed, paraffin-embedded specimens of 111 SCCHN patients treated with concurrent chemoradiotherapy (carboplatin, 100 mg/m2, four to six times every week; total radiation therapy dose of 40-65 Gy over 4-6.5 weeks). Multivariate analysis indicated that nodal status was a significant indicator of overall survival (OS; P = 0.001) and locoregional control (LRC; P = 0.002). In a univariate analysis, patients with a low MIB-1-positive index (< 40%) had better OS than those with a high MIB-1-positive index (> or = 40%; P = 0.013), although the difference was not statistically significant in a multivariate analysis (P = 0.060). Patients with bcl-2-positive tumors had better LRC than those with bcl-2-negative tumors, based on a multivariate analysis (P = 0.017). No statistically significant association was found between p53 or bax expression and clinical outcome. These results indicate that nodal status is the major prognostic factor in SCCHN patients treated with concurrent chemoradiotherapy. In addition, our findings suggest that bcl-2 positivity is associated with better LRC and that the proliferative activity of tumor cells might be prognostic for OS.

Antigens, Nuclear↗
PubMed1998

Invasive Streptococcus pneumoniae infection in Latin American children: results of the Pan American Health Organization Surveillance Study.

Protein-polysaccharide conjugate vaccines against Streptococcus pneumoniae promise to be an effective public health intervention for children, especially in an era of increasing antimicrobial resistance. To characterize the distribution of capsular types in Latin America, surveillance for invasive pneumococcal infection in children < or = 5 years of age was done in six countries between February 1993 and April 1996. Fifty percent of 1,649 sterile-site isolates were from children with pneumonia, and 52% were isolated from blood. The 15 most common of the capsular types prevalent throughout the region accounted for 87.7% of all isolates. Overall, 24.9% of isolates had diminished susceptibility to penicillin: 16.7% had intermediate resistance and 8.3% had high-level resistance. Three customized vaccine formulas containing 7, 12, and 15 capsular types were found to have regional coverages of 72%, 85%, and 88%, respectively. This study emphasizes the need for local surveillance for invasive pneumococcal disease prior to the development and evaluation of protein-polysaccharide conjugate vaccines for children.

Bacterial Vaccines↗