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Biomedical subjects

T Okuma

Publications and source records attributed to T Okuma.

At least 19 recordsLinked to original sources
PubMed2002

Adult case of squamous cell carcinoma arising on congenital esophageal stenosis due to fibromuscular hypertrophy.

This study relates to an adult case of squamous cell carcinoma arising on congenital esophageal stenosis. The patient was a 65-year-old man who had suffered from dysphagia and vomiting since birth and was diagnosed as having congenital esophageal stenosis. The patient had not received any treatment because his symptoms were mild. The patients suffered from severe dysphagia since he was 20 years old and had received balloon therapies several times; however, the effects were transient. After admission to our hospital, he underwent a transhiatal esophagectomy without thoracotomy. Histopathological examination of the resected specimen revealed a thick muscular mucosae associated with hypertrophic fibromuscular components and poorly to moderately differentiated squamous cell carcinoma in the region of stenosis. This case report is the first of a patient with squamous cell carcinoma arising on congenital esophageal stenosis.

Aged↗
PubMed2001

Risk stratification using serum concentrations of cardiac troponin T in patients with end-stage renal disease on chronic maintenance dialysis.

BACKGROUND: It has been recently suggested that cardiac troponin T (cTnT) may be more sensitive than troponin I (cTnI) for subclinical myocardial cell injury in patients on chronic dialysis. METHODS: We prospectively compared the predictive value of cTnT with cTnI, atrial (ANP) and brain natriuretic peptide (BNP) in 100 consecutive outpatients on chronic dialysis without acute coronary syndromes over a period of 3 months, and assessed whether the combination of cTnT with clinical information including age, duration of dialysis, and medical histories was useful for risk stratification of these patients. During the 2-year follow-up period, 19 patients died, mostly due to cardiac causes (53%). RESULTS: The area under the receiver operator characteristic (ROC) curve for the cTnT as predictor of both overall and cardiac death was significantly greater than the area under the cTnI curve (p < 0.0001 and p = 0.01), the BNP curve (p < 0.001 and p < 0.01) or the ANP curve (p < 0.0001 and p < 0.005). In a stepwise multivariate Cox regression analysis, only cTnT (p < 0.05 and p < 0.01) and a history of heart failure requiring hospitalization (p < 0.05 and p < 0.005) were independent predictors of both all cause and cardiac mortality. Using parameters of cTnT > or =0.1 microg/l and/or history of heart failure, the overall and cardiac mortality rate for the low risk group (n=66) were 4.5% and 1.5%, respectively, 40% and 16% for the intermediate risk group (n=25), and 67% and 56% for the high risk group (n=9). CONCLUSION: cTnT concentrations offer a higher prognostic accuracy than cTnI, ANP and BNP in patients on chronic dialysis. The combination of elevated cTnT and a history of heart failure may be a highly effective means of risk stratification of these patients.

Adult↗
PubMed2001

Ground performance of air conditioning and water recycle system for a Space Plant Box.

Researchers from 5 Japanese universities have developed a plant growth facility (Space Plant Box) for seed to seed experiments under microgravity. The breadboard model of the Space Plant Box was fabricated by assembling subsystems developed for microgravity. The subsystems include air conditioning and water recycle system, air circulation system, water and nutrient delivery system, lighting system and plant monitoring system. The air conditioning and water recycle system is simply composed of a single heat exchanger, two fans and hydrophilic fibrous strings. The strings allow water movement from the cooler fin in the Cooling Box to root supporting materials in the Plant Growth Chamber driven by water potential deficit. Relative humidity in the Plant Growth Chamber can be changed over a wide range by controlling the ratio of latent heat exchange to sensible heat exchange on the cooling fin of the heat exchanger. The transpiration rate was successfully measured by circulating air inside the Plant Growth Chamber only. Most water was recycled and a small amount of water needed to be added from the outside. The simple, air conditioning and water recycle system for the Space Plant Box showed good performance through a barley (Hordeum vulgare L.) growth experiment.

Air Conditioning↗
PubMed2000

Mediastinal growing teratoma syndrome.

A 27-year-old man had undergone orchiectomy and chemotherapy for testicular cancer. Despite normalization of raised tumor marker levels after postoperative chemotherapy, computed tomographic scanning demonstrated multiple swellings of the para-aortic lymph nodes with extension from beneath the aortic arch to the bifurcation of the descending aorta. Open biopsies of the para-aortic lymph nodes disclosed mature teraroma without malignant cells. The patient presented the typical features of mediastinal and retroperitoneal growing teratoma syndrome. A two stage resection of the tumors was performed via laparotomy and left thoracotomy. Histological examination of the resected specimens revealed a mature teratoma component without malignant cells. Upon follow-up sixteen months later, the patient was well and without recurrence.

Adult↗
PubMed2000

Microbial contamination of enteral feeding formulas and diarrhea.

Twenty-five medical and surgical patients receiving liquid ready-to-use sterile enteral formulas were evaluated prospectively to investigate the relation of diarrhea to serum albumin level, total lymphocyte count, delayed hypersensitivity to purified protein derivative, antibiotic therapy, administration rate and site of enteral formula, and microbial contamination of enteral feeds. Formulas were administered to 6 patients with hang times of up to 6 h by pump-assisted continuous drip and to 19 patients with hang times of up to 3 h as a bolus feeding. Samples of formulas for microbial culture were obtained aseptically before and after feeding on the first and eighth day of the study period. The incidence of microbial contamination of the formula before and after feeding was 1 of 49 samples (2.0%) and 10 of 48 samples (20.8%), respectively. There were 2 patients with diarrhea, which occurred on the second day. Formula samples from 2 patients (100%) with diarrhea and 2 samples from 23 patients (8.7%) without diarrhea were contaminated with 10(4) cfu/mL or more, respectively. A significant difference (P = 0.04) was detected between the two groups. The other factors studied showed no significant association with the incidence of diarrhea. In conclusion, contaminated formula appears to play a significant role in the etiology of diarrhea in patients receiving enteral feeding.

Acinetobacter↗
PubMed2000

Asymmetric interhemispheric delta waves during all-night sleep in humans.

OBJECTIVE: In order to better understand the asymmetry of brain function during sleep, period-amplitude analysis of delta EEG activity was performed on polysomnograms (PSGs) in normal humans. Twenty healthy, right-handed male volunteers aged 22-35 years (mean age 27.2 years) served as subjects in this study. METHODS: EEGs were recorded from disc electrodes placed at bilateral frontal, central, parietal, occipital, anterotemporal and posterotemporal (10-20 electrode system) sites using A1+A2 for reference. Period-amplitude analysis was performed by the zero-crossing method using the Medilog Sleep Analyzing Computer. RESULTS: Delta counts in the right frontal and central regions during all-night sleep were significantly greater than in those of the left; total delta counts of the right frontal region were greater than those of the left in 18 of the 20 subjects. There were no significant differences in delta counts between the left and right hemispheres in parietal, occipital, anterotemporal, and postero-temporal regions. CONCLUSIONS: These results suggest distinct laterality in the number of delta waves in the frontal and central regions, reflecting functional asymmetry of the brain during sleep.

Adult↗
PubMed1999

In vitro SUMO-1 modification requires two enzymatic steps, E1 and E2.

The SUMO-1 has been identified as a protein that is highly similar to ubiquitin and shown to conjugate to RanGAP1, PML, Sp200 and I kappa B alpha. The conjugation steps are thought to be similar to those of ubiquitination; and human Ubc9, which is homologous to the E2 enzyme for the ubiquitin conjugation step, was identified and shown to be necessary for the conjugation of SUMO-1 to its target protein. Other essential enzymes involved in this modification, however, remain to be clarified. Here we cloned human Sua1 (SUMO-1 activating enzyme) and hUba2, which are human homologs of yeast Saccharomyces cerevisiae Aos1 and Uba2, respectively. The recombinant proteins, Sua1p and hUba2p, formed a complex. In this complex, hUba2 bound SUMO-1 and this complex had the activity of the SUMO-1 activating enzyme. Furthermore, in an in vitro system, RanGAP1 was modified by SUMO-1 in the presence of Sua1p/Uba2p and hUbc9p, showing that the modification of SUMO-1 could be catalyzed by two enzyme steps, although ubiquitination usually requires three enzyme steps.

Amino Acid Sequence↗
PubMed1999

Does neoadjuvant chemotherapy for carcinoma in the thoracic esophagus increase postoperative morbidity?

OBJECTIVES: The aims of this study were to examine whether neoadjuvant chemotherapy for a carcinoma in the thoracic esophagus increased the incidence of postoperative complications, and which clinicopathological factors may affect postoperative complications after esophagectomy. SUBJECTS AND METHODS: One hundred and forty-four patients who underwent neoadjuvant chemotherapy followed by esophagectomy for a carcinoma in the thoracic esophagus were reviewed in a retrospective study. Ninety-six patients received neoadjuvant chemotherapy and 48 did not. The postoperative complications were grouped either general complications (Complications A) or surgery-related complications (Complications B). Complications A consisted of pulmonary, cardiac, hepatic, renal, and neurological complications, and catheter sepsis. Complications B consisted of a gastrointestinal tract leak, gastrointestinal tract necrosis, an intrathoracic or intraabdominal abscess, hemorrhage, ileus, and vocal cord palsy. In these two categories of complications, 17 factors obtained from subjects were compared between patients with complications and those without by univariate and multivariate analyses. RESULTS: The patient characteristics did not differ between patients who received neoadjuvant chemotherapy and those without. The preoperative serum albumin level was higher in patients without complication than in those with complication in both two categories of complications (Complications A: p = 0.001, Complications B: p = 0.05). The proportion of patients who received neoadjuvant chemotherapy did not differ between patients with complication and those without complication in either category of complications. Multivariate analysis showed that preoperative Onodera's Prognostic Nutritional Index was the only factor reducing the incidence of complications A (p = 0.02, Odds ratio: 0.63). CONCLUSION: Neoadjuvant chemotherapy was well tolerated and was not associated with any increased morbidity or mortality after esophagectomy for a carcinoma in the thoracic esophagus.

Chemotherapy, Adjuvant↗
PubMed1999

Indications for three-field dissection followed by esophagectomy for advanced carcinoma of the thoracic esophagus.

OBJECTIVE: The aim of this study was to evaluate the indication for 3-field lymphadenectomy (3-field dissection) followed by esophagectomy for locally advanced carcinoma of the thoracic esophagus in the presence of lymph node metastasis. METHODS: From January 1983 to December 1995, 86 patients with thoracic esophageal carcinoma invading muscularis propria or adventitia underwent radical subtotal esophagectomy after preoperative chemotherapy. Forty-six of the 86 patients underwent a 2-field dissection (mediastinal and abdominal nodes, group A), and 40 patients underwent a 3-field dissection (bilateral cervical, mediastinal, and abdominal nodes, group B). Survival curves were compared between the 2 groups after stratification according to the degree of lymph node involvement (number of positive nodes and involvement of intrathoracic or intrathoracic recurrent nerve chain nodes). Potential prognostic factors of these 86 patients were evaluated by means of Cox regression analysis. RESULTS: There were no significant differences in age, sex ratio, depth of tumor invasion, pTNM classification, or number of positive nodes between the 2 groups. Among patients with positive intrathoracic nodes, the 5-year survival of group B (42%) was significantly longer than that of group A (13%, generalized Wilcoxon test P =.02). Among patients with 1 to 4 positive nodes, the 5-year survival of group B (54%) was significantly higher than that of group A (22%, P =.01). Multivariate analysis revealed the number of positive nodes, age, and pT4 stage to be significant predictors of survival in patients with thoracic esophageal carcinoma. CONCLUSIONS: Three-field dissection for advanced carcinoma of the thoracic esophagus is effective in patients with 1 to 4 positive nodes.

Aged↗
PubMed1999

Laterality of delta waves during all-night sleep.

In order to clarify the functional asymmetry of the brain function during sleep, period-amplitude analysis of delta electroencephalogram activity was performed on polysomnograms in 12 right-handed healthy males. Electroencephalograms were recorded from disc electrodes placed at C3, C4, O1 and O2 (10-20 electrode system), using A1 +A2 for reference. Although there were no significant differences in delta counts between O1 and O2, delta counts of C3 were significantly larger than those of C4. These results suggest that there exists distinct laterality in the number of delta waves in the central region, reflecting the functional asymmetry of the brain during sleep.

Adult↗
PubMed1999

The prognostic significance of cell cycle markers in esophageal cancer after neoadjuvant chemotherapy.

Proliferating cell nuclear antigen (PCNA), p27 and cyclin A were analyzed by immunohistochemistry in 89 patients (untreated control n = 40, neoadjuvant chemotherapy n = 49) with esophageal cancer invading the submucosal lesion. The mitotic index (MI) was calculated as the percentage of mitotic cells. In control subjects, the mean PCNA, p27, cyclin A and MI were, respectively, 60.4%, 18.0%, 19.9% and 1.7%; in the chemotherapy group, these values were 46.8%, 15.1%, 18.0% and 1.2% respectively. Neoadjuvant chemotherapy decreased PCNA and the MI significantly. As prognostic indicators, PCNA and the MI were significant in control subjects and p27 and cyclin A were significant in the chemotherapy group. Using multivariate analysis, p27 was a prognostic factor in both groups and cyclin A was prognostic only in the chemotherapy group. Although PCNA and the MI were useful growth and prognostic markers in untreated control subjects, their significance was lost after neoadjuvant chemotherapy. p27 and cyclin A were determined to be significant markers in the neoadjuvant chemotherapy group, especially p27, which was independent in both groups.

Aged↗
PubMed1999

Association between delta waves during sleep and negative symptoms in schizophrenia. Pharmaco-eeg studies by using structurally different hypnotics.

We examined the effects of benzodiazepine (BZD) hypnotics and zopiclone (ZPC), a nonbenzodiazepine hypnotic, on sleep and psychiatric symptoms in schizophrenia, as well as the clinical correlates of these variables. Seven male schizophrenic patients chronically taking neuroleptics together with BZD were studied. We replaced BZD with ZPC and performed polysomnography (PSG) and Brief Psychiatric Rating Scale (BRPS) scoring before and after an 8-week ZPC treatment. The replacement of BZD with ZPC increased the mean amplitude of high-amplitude low-frequency delta waves on the frontal derivation recognized by period-amplitude analysis, and it decreased the BPRS negative-symptom score. Under the BZD treatment, the negative-symptom score correlated inversely with the mean amplitude of high-amplitude low-frequency delta waves. This correlation was weak and not significant under the ZPC treatment. Therefore, delta waves during sleep have a close correlation to negative symptoms in schizophrenia, and such a correlation could be influenced by hypnotics. Although these are preliminary findings, it was suggested that, compared with BZD, ZPC might be a beneficial hypnotic in regard to both sleep and negative symptoms of chronic schizophrenic patients.

Adult↗
PubMed1998

A polysomnographic study of sleep patterns in normal humans with low- or high-anxiety personality traits.

To clarify the effects of anxiety-related personality traits on sleep patterns, polysomnographic examinations (PSG) were performed over 4 consecutive nights on normal humans who tested within the low- or high-anxiety ranges. The subjects consisted of two groups of six male university students who scored either less than 45 points (low-anxiety group) or more than 55 points (high-anxiety group) on the Spielberger's State Trait Anxiety Inventory. Compared to the levels of sleep change in the high-anxiety group, the low-anxiety group exhibited a greater change in REM sleep and stage 2 sleep. The REM sleep in the low-anxiety group was shorter on the first and second nights compared to the third and fourth nights, and the stage 2 sleep was longer on the first night than on the remaining three nights. Thus, the low-anxiety group showed a first-night effect followed by partial recovery on the second night, while the high-anxiety group exhibited no obvious first-night effect. These results suggest that there is a difference in sleep patterns, assessed by consecutive PSG, between those with low- and high-anxiety traits, and that anxiety-related personality traits attenuate the occurrence of the first-night effect, reflecting a lower adaptability to a novel environment.

Adult↗
PubMed1998

A history of investigation on the mood stabilizing effect of carbamazepine in Japan.

A history of investigation on the antimanic and prophylactic effects of carbamazepine in Japan is described. Following the initial open trials in the early 1970s in which the antimanic and prophylactic effects of carbamazepine were indicated for the first time in the world, the mood stabilizing effect was confirmed by the double blind studies which were performed with a multi-institutional cooperation in Japan in the late 1970s. During the course of the double blind trials, the problem of different therapeutic dosages of psychotropic drugs between Japan and Western countries emerged; that is, the doses of chlorpromazine and lithium carbonate, which were used as the control drugs to carbamazepine in the two double-blind group-comparison studies in Japan, were both much lower than the dosage used in most of the Western countries. The low dosage of control drugs made the evaluation of the results of the double blind studies performed in Japan difficult, and caused a delay of publication in the Western journals of the results. Whether the difference is due to biological factors or to psychosocial and cultural factors is an important problem in psychopharmacology and should be investigated further.

Anticonvulsants↗
PubMed1997

Relationship between the effects of a hypnotic drug, zopiclone, on polysomnography and on daytime EEGs.

The correlation between the effects of zopiclone (ZPC), a nonbenzodiazepine hypnotic drug, on sleep polysomnograms and on daytime EEGs was examined in 12 healthy adult male volunteers. Sleep polysomnograms were recorded after a single oral administration of ZPC 10 mg or placebo according to the double-blind crossover method. Daytime EEGs were recorded after the administration of ZPC, 7.5 mg, or placebo in the same manner, and recorded for 3 min with closed eyes at rest. Then, square roots of the absolute power (amplitude) of the delta-, theta-, alpha-, and beta-activities were calculated from the power spectrum obtained by the fast Fourier transform method. As a result, ZPC decreased the percentage of stage 1 sleep in total sleep time, while it increased the percentage of stage 2, total sleep time, and time of slow wave sleep in the first and second sleep cycles (SWS 1 and 2). Changes in SWS 1 and 2 correlated positively with the amplitude changes in daytime resting delta-activity. This indicates that the increase of SWS due to ZPC could be related to the change of delta-activity in the daytime resting EEG.

Adult↗
PubMed1997

Zopiclone versus diazepam effects on EEG power maps in healthy volunteers.

EEG effects of zopiclone (7.5 mg), a cyclopyrrolone derivative with hypnotic action, were compared with effects of diazepam (10 mg). Multichannel EEG recordings, double-blind crossover trials with placebo, and oral single doses were used in healthy volunteers. Vigilance-controlled EEG before and after zopiclone (and placebo), and before and after diazepam (and placebo) were analyzed into FFT power spectra. Effects were assessed as placebo-referred pre-post-medication power differences in four frequency bands. Overall statistics showed significant (P < 0.007) global differences between medication effects in the delta frequency band (0.5-3.5 Hz). After zopiclone, fronto-central delta increased bilaterally, whereas after diazepam delta decreased over centro-parietal to right temporo-occipital regions. These spatially different brain electric effects show that different neuronal populations must have become active in response to zopiclone and diazepam.

Adult↗
PubMed1997

[Study of diazepam with quantitative EEGs taken with eyes opened and topography].

Diazepam is a representative drug of benzodiazepines. The subjects were 9 right-handed healthy male volunteers 21 25 years of age. Double blind crossover trials with placebo control were conducted in a random sequence at an interval of 1 week. Diazepam 10 mg and placebo were administered as single oral doses. Three-minute EEGs were recorded with subjects' eyes opened before and 2 h after drug administration. One-minute out of the 3-minute EEGs was analyzed with FFT, and the absolute amplitude power (microV) was calculated. These results were subjected to Student's t-test (double difference) and displayed with topographic maps (t statistic significance probability mapping). Diazepam decreased the delta absolute amplitude power over left-parietal dominance, theta absolute amplitude power diffusely and alpha absolute amplitude power over parietal region dominance. It also increased the beta absolute amplitude power over left-antero-temporal region dominance. The EEG profiles taken with subjects' eyes open were different from those of diazepam with eyes-closed vigilance controlled concerning the degree of decrease of delta and beta activities and region of the effect on alpha activity.

Adult↗