Biomedical subjects

T Hirai

Publications and source records attributed to T Hirai.

At least 19 recordsLinked to original sources

PubMed1999

Effects of lung volume on lung and chest wall mechanics in rats.

To investigate the effect of lung volume on chest wall and lung mechanics in the rats, we measured the impedance (Z) under closed- and open-chest conditions at various positive end-expiratory pressures (0-0.9 kPa) by using a computer-controlled small-animal ventilator (T. F. Schuessler and J. H. T. Bates. IEEE Trans. Biomed. Eng. 42: 860-866, 1995) that we have developed for determining accurately the respiratory Z in small animals. The Z of total respiratory system and lungs was measured with small-volume oscillations between 0.25 and 9.125 Hz. The measured Z was fitted to a model that featured a constant-phase tissue compartment (with dissipation and elastance characterized by constants G and H, respectively) and a constant airway resistance (Z. Hantos, B. Daroczy, B. Suki, S. Nagy, and J. J. Fredberg. J. Appl. Physiol. 72: 168-178, 1992). We matched the lung volume between the closed- and open-chest conditions by using the quasi-static pressure-volume relationship of the lungs to calculate Z as a function of lung volume. Resistance decreased with lung volume and was not significantly different between total respiratory system and lungs. However, G and H of the respiratory system were significantly higher than those of the lungs. We conclude that chest wall in rats has a significant influence on tissue mechanics of the total respiratory system.

Airway Resistance↗

PubMed1999

Acute response of the lung mechanics of the rabbit to hypoxia.

We measured the change in total lung resistance (RL) and that in total lung elastance (EL) induced by hypoxia (n = 7) and compared the results with those by intravenous histamine bolus (n = 5) at three different positive end-expiratory pressure (PEEP) levels (2, 5, and 8 hPa) in open-chest and vagotomized rabbits. The percent increase ratio of RL (PIRR) and EL (PIRE) was defined as the change in RL and EL, respectively, induced by hypoxia compared with that in the normoxic condition, expressed as a percentage. PIR values for the change in RL and EL induced by bolus injection of histamine were also calculated. The PIRR and PIRE induced by hypoxia and by histamine were positive by a statistically significant amount at every PEEP level, except for the PIRE value at 8-hPa PEEP in the hypoxic challenge. The PIRE-to-PIRR ratio values in the hypoxic challenge at 2-hPa PEEP were significantly larger than those in the histamine challenge (hypoxia: 0.91 +/- 0.23%; histamine: 0.37 +/- 0. 065%, P < 0.05). The increase in EL induced by histamine in the acute phase has been reported to be mainly derived from tissue distortion secondary to bronchial constriction. Thus our results suggest that a part of the increase in EL by hypoxia was originated in different parenchymal responses from histamine and imply that this hypoxic response of lung parenchyma is sensitive to the increase in parenchymal tethering at high PEEP levels.

Airway Resistance↗

PubMed1998

Childhood parental loss and schizophrenia: evidence against pathogenic but for some pathoplastic effects.

Childhood parental loss has been associated with a number of psychiatric disorders in adulthood. The present article aims to examine, firstly, the etiologic relationship between early parental loss and later development of schizophrenia and, secondly, the pathoplastic effect of the former on the symptomatology of the latter. We have administered semi-structured interviews inquiring into psychopathology and early separation experiences to a representative sample of first-visit patients to the 31 hospitals and clinics all over Japan (n=1963) and also to a community sample in a small city in Japan (n=218). When 225 patients diagnosed with schizophrenia according to DSM-III-R criteria were compared with 122 healthy control subjects without any lifetime psychiatric disorder, controlled for sex and age, there was no statistically significant difference in the rates of childhood parental loss (death or separation). As regards the pathoplastic effects, it was found that schizophrenic men were less likely to present with negative symptoms if they had experienced separation from the father, and were more likely to show panic attacks if they had experienced separation from the mother. Schizophrenic women were more likely to present with hallucinations if they had suffered any loss of the father. Childhood parental loss is not pathogenic of schizophrenia but appears to exert some pathoplastic influences on its presenting symptoms.

Adult↗

PubMed1998

Prognostic value and clinical implications of disseminated cancer cells in the peritoneal cavity detected by reverse transcriptase-polymerase chain reaction and cytology.

Free cancer cells exfoliated from the cancer-invaded serosa contribute to peritoneal dissemination, the most frequent pattern of recurrence in gastric carcinoma patients. This study was designed to evaluate the prognostic relevance of such free cells in peritoneal washes detected by reverse transcriptase-polymerase chain reaction (RT-PCR) and cytology. RT-PCR analysis with primers specific for carcinoembryonic antigen and conventional cytologic examination by Papanicolaou staining were performed on peritoneal washes, collected at laparotomy from 148 gastric carcinoma patients. Prognostic analyses were performed with 1) death due to cancer recurrence and 2) peritoneal dissemination as endpoints. RT-PCR was found to be more sensitive than cytologic examination for detection of free cancer cells in the peritoneal washes, with a higher detection rate for each of the T categories in the tumor-node-metastasis (TNM) classification. Five patients with synchronous or recurrent peritoneal dissemination were found among 17 patients with positive RT-PCR and negative cytologic results. Both positive cytologic results and positive RT-PCR results had significant influences over the survival of patients with advanced gastric carcinomas (n = 75, p < .002). Detection of free cancer cells in peritoneal washes, most reliably by RT-PCR, is promising as a predictor of peritoneal dissemination in patients with gastric carcinoma.

Carcinoembryonic Antigen↗

PubMed1998

Lymph node status assessment for gastric carcinoma: is the number of metastatic lymph nodes really practical as a parameter for N categories in the TNM Classification? Tumor Node Metastasis.

BACKGROUND AND OBJECTIVES: The anatomical extent of nodal metastasis has been replaced by the number of metastatic nodes as a key indicator of prognosis (pN categories) in the fifth edition of Tumor Node Metastasis Classification for gastric carcinoma by the International Union Against Cancer. The rate of metastatic nodes among all the nodes harvested is also a good prognostic factor. The object of this study is to evaluate which of the three parameters for the assessment of nodal status is the most appropriate for use in the stage classification. METHODS: Retrospective survival analyses were performed in 656 consecutive patients with advanced gastric carcinoma who underwent D2 lymphadenectomy and for whom histopathologic data of more than 20 lymph nodes were available. RESULTS: Although all three systems served well to classify the patients into distinct groups in terms of survival curves, stratification by the number of metastatic nodes was vulnerable to stage migration because of differences in the number of lymph nodes harvested. Such stage migration was not evident for the other two parameters. CONCLUSIONS: Lymph node metastatic rate can be recommended as an internationally applicable parameter for lymph node involvement of gastric carcinoma.

Adult↗

PubMed1998

Clinical evaluation of adjuvant chemoradiotherapy with CDDP, 5-FU, and VP-16 for advanced esophageal cancer.

OBJECTIVES: The aim of this study was to evaluate the efficacy of adjuvant chemoradiotherapy following surgery in patients with advanced esophageal cancer. SUBJECTS AND METHODS: We followed the cases of 57 such patients treated at our hospital, involving 19 who received adjuvant chemoradiotherapy (CR group), 19 who received radiotherapy alone (R group), and 19 who did received neither (N group). In the CR group, chemotherapy, consisting of cis-diaminodichloroplatinum (CDDP), 5-fluorouracil (5-FU), and etoposide (VP-16), was combined with radiotherapy was administered from 4 weeks after surgery. Concurrent radiotherapy was started at 3 weeks after esophagectomy. CDDP at 50 mg/m2 was administered on days 1 and 7.5-FU at 500 mg/m2 and VP-16 at 60 mg/m2 were administered on days 3, 4, and 5. Thirteen patients (68.4%) were treated with more than 2 cycles of chemotherapy combined with radiation. RESULTS: Side-effects of severe anorexia (grade 3) and leukocytopenia (< 1900/microliter) were observed in 47% and 39% of the patients, respectively. However no treatment-related death was observed. The 5-year-survival rate was 25.2%, 18.9%, and 15.8%, in the CR group, R group, and N group, respectively. The recurrence rate was 66.7% in the CR group, which was higher than in the matched control groups (46.2% in the N group and 54.5% in the R group), but with no a significant difference. CONCLUSION: These results suggested that adjuvant chemoradiotherapy did not contribute to improvement in prognosis for these patients with advanced esophageal cancer.

Adult↗

PubMed1998

[Massive mediastinal bleeding due to spontaneous rupture of the vertebral artery in von Recklinghausen disease].

In Von Recklinghausen disease, patients rarely demonstrate vascular abnormalities, but several reports have noted massive bleeding from vascular rupture. A 28-year-old man with Von Recklinghausen disease was admitted to our hospital because of swelling on the left neck accompanied by dyspnea. Neck and thoracic CT revealed a high density shadow on the mediastinum and left upper thorax which was suspected to indicate hemomediastinum. Under suspicion of bleeding from the intrathoracic artery, the patient underwent on surgery. Massive hematoma disrupted visual recognition of bleeding point, but under anatomical consideration, we concluded that the bleeding was from the ruptured left vertebral artery (VA) which branched independently from the aorta. The left VA was ligated distally and proximally. Left subclavian artery, injured unexpectedly, was not reconstructed but sutured carefully because of its fragility. Thus massive bleeding was controlled. Histology of the neighboring subclavian artery revealed involvement with neurofibrinomatosis. Although the patient's left arm demonstrated a slightly low blood pressure, he was discharged without complaint on the 56th postoperative day.

Adult↗

PubMed1998

Virtual MRI endoscopy of the intracranial cerebrospinal fluid spaces.

We used constructive interference in steady state (CISS) 3D Fourier transform (3DFT) MRI data sets to obtain three-dimensional (3D) virtual MRI endoscopic views of the intracranial cerebrospinal fluid (CSF) spaces, processing them with a commercially available perspective endoscopic algorithm. We investigated the potential of the intracranial virtual MRI endoscopy applied to visualisation of the pathology in 13 patients with surgically confirmed trigeminal neuralgia (3), hemifacial spasm (3), acoustic neuroma (3), suprasellar germinoma (1), Langerhans cell histiocytosis (1), lateral ventricle nodules (1) and pituitary dwarfism (1). All images were acquired using a 1.5-T imager employing a circular polarised head coil. The CISS-3DFT data sets were transferred to a workstation for processing with the perspective endoscopic algorithm. Postprocessing for virtual MRI endoscopy was possible for all data sets. The lesions in 12 patients, and their complex anatomical relationships with the surrounding structures, were well seen on the 3D images. A small acoustic neuroma in the internal auditory meatus was not seen using virtual endoscopy. Although virtual MRI endoscopy has limitations, it provides 3D images which cannot be acquired using any other procedure.

Adolescent↗

PubMed1998

Poor prognosis in esophageal cancer patients with postoperative complications.

We investigated the relationship between postoperative complications and prognosis in esophageal cancer patients. Two hundred five patients with esophageal cancer were divided into three case groups. Group A (n = 100) consisted of cases without postoperative complications. Groups B (n = 58) and C (n = 47) consisted of cases with minor and major postoperative complications. The 5-year survival rates were 41.8%, 21.3%, and 20.2% in groups A, B, and C, respectively. There was a significant difference in the prognosis between groups A and B, and also between groups A and C. Any patients who died within 5 years without a relapse their cases were excluded from the study; the 5-year survival rates were 46.7%, 32.3%, and 22.5% in groups A, B, and C, respectively, with a significant difference between groups A and B. There were no significant differences between the three groups regarding the patient characteristics. These results therefore indicate that postoperative complications might contribute to a poor prognosis in cancer patients.

Esophageal Neoplasms↗

PubMed1998

Resection of pulmonary metastases in six patients with disease-free interval greater than 10 years.

BACKGROUND: The relationship between disease-free interval (DFI) and prognosis has been discussed; however, there is little information on long-term DFI. In this study, we surveyed the cases of pulmonary metastases with DFI greater than 10 years. METHODS: Between January 1980 and December 1995, we saw 6 patients with DFI greater than 10 years. All the patients had a histopathologic diagnosis of pulmonary metastases based on surgical resection, and the patients' characteristics and clinical course were reviewed. RESULTS: The median age was 63 years. Primary sites were breast in 2 patients, and one case each of skin, colon, thyroid, and bladder. The numbers of metastases were one in 4 patients and two in 2 patients. The median DFI was 134 months (range, 127 to 235 months). The median tumor-doubling time was 227 days (range, 80 to 815 days). All the patients underwent a lobectomy. Three patients with metastases from the bladder, colon, and breast died of recurrence. One patient with metastasis from the thyroid died of heart failure. Two patients with metastases from breast and skin cancer survived for more than 3 years. CONCLUSIONS: Early death occurred regardless of the long DFI, suggesting that intensive follow-up is mandatory for patients with DFI greater than 10 years.

Adenocarcinoma↗

PubMed1998

Surgery for thoracic empyema concurrent with rupture of lung abscesses in a child.

The authors report surgical treatment for thoracic empyema concurrent with rupture of lung abscesses and completely collapsed lung in a child. Right middle lobectomy for ruptured abscess, debridement and closure with interrupted sutures for another abscess in the lower lobe, and decortication were performed. Positive-pressure ventilation was needed to prevent reexpansion pulmonary edema because of long-term collapsed lobes. The patient is doing well with no recurrent empyema or thoracic deformity at 3 years postoperation.

Empyema, Pleural↗

PubMed1998

Primary adenoid cystic carcinoma in the lung: report of two cases and therapeutic considerations.

Primary adenoid cystic carcinoma in the lung is an uncommon disease, which is regarded as a slow growing low-grade malignancy. However, this disease has a high risk of incomplete resection because of its unique histological invasion patterns. The cases of two patients who recently underwent surgery for adenoid cystic carcinoma in the lung are reported. Both patients received postoperative radiotherapy treatment as a follow-up to a histologically incomplete resection. Both patients have survived for 51 months and 7 months, respectively, with no recurrence. Postoperative radiotherapy is an acceptable treatment of choice to control residual lesions and provides long-term survival even in cases of incomplete resection.

Aged↗

PubMed1998

The number of metastatic lymph nodes: a promising prognostic determinant for gastric carcinoma in the latest edition of the TNM classification.

BACKGROUND: The number of metastatic regional lymph nodes determines the new pN categories in the 5th edition of the TNM classification. STUDY DESIGN: Our retrospective study was conducted to compare the new method of defining lymph node status with the conventional classification, consisting of the anatomic extent of lymph node metastases, a well-established prognostic factor. The study was based on clinical data for 493 patients with gastric carcinomas who underwent potentially curative operations and had histologically confirmed nodal metastases. These patients were stratified into 1) n categories according to the Japanese Classification of Gastric Carcinoma, 2) the new pN categories, and 3) the pN categories determined by the number of metastatic perigastric nodes resected by standard D1 gastrectomy. Survival data were analyzed for each group. RESULTS: The number of metastatic nodes after D2 lymphadenectomy reflected prognosis well and was shown by multivariate analysis to be a strong independent prognostic factor. When the classification was performed limited to the metastatic perigastric nodes, stage migration was evident, but the variable remained competent as a prognostic indicator. CONCLUSIONS: The number of metastatic nodes is a promising determinant in the new international stage classification.

Adult↗

PubMed1998

Identification of estrogen-modified nucleosides from calf thymus DNA reacted with 6-hydroxyestrogen 6-sulfates.

Two estrogen sulfates, pyridinium 3-methoxyestra-1,3, 5(10)-trien-6alpha-yl sulfate (3MeE-6alpha-S) and its 6beta-isomer (3MeE-6beta-S), synthesized as model compounds to demonstrate the carcinogenesis of estrogen, were found to react with calf thymus DNA to produce steroid-modified DNA adducts. Digestion of the DNA by nuclease P1 and phosphodiesterase I followed by alkaline phosphatase gave a deoxyribonucleoside fraction, of which N2-[3-methoxyestra-1,3, 5(10)-trien-6alpha-yl]deoxyguanosine, N2-[3-methoxyestra-1,3, 5(10)-trien-6beta-yl]deoxyguanosine, N6-[3-methoxyestra-1,3, 5(10)-trien-6beta-yl]deoxyadenosine, and N6-[3-methoxyestra-1,3, 5(10)-trien-6alpha-yl]deoxyadenosine (identified as a base adduct) were identified using HPLC by comparing them with authentic specimens prepared by reacting dG and dA with both sulfates. No steroid-dC adduct was detected in the digestion products of the DNA adduct, although dC reacted with the sulfates to form N4-[3-methoxyestra-1,3,5(10)-trien-6beta-yl]deoxycytidine. These results mean that estrogen 6-sulfate has an ability to modify DNA via the amino group of a guanine or adenine residue in DNA. The present studies imply that a sequential metabolism (hydroxylation and sulfation) at the C6-position of the estrogen molecule causes damage to DNA.

Animals↗

PubMed1998

Evaluation of chewing activity in the elderly person.

In the present study, we examined the chewing performance of 70 elderly persons. Self-assessment of chewing problems and clinical classification using the modified Eichner index showed little correlation (Kappa value = 0.28; 95% confidence interval (CI) = 0.05-0.51). The sensitivity and specificity were 0.52 and 0.76, respectively. On the other hand, the mastication score determined by evaluation of a questionnaire on food intake and classification using the modified Eichner index showed high agreement (Kappa value = 0.73; 95% CI = 0.50-0.96). The sensitivity and specificity were 0.76 and 0.95, respectively. The mastication score showed significant correlation with other masticatory functions such as maximum biting force, occlusal contact area and the number of missing teeth (P < 0.01). These results suggest that the use of a questionnaire on food intake would be informative for epidemiological surveys of chewing activity in the elderly.

Aged↗

PubMed1998

The relationship between occlusal support and physical exercise ability.

This study was conducted to elucidate the relationship between the presence of occlusal support in edentulous subjects and their ability for physical exercise. Ten complete denture wearers were selected and instructed to jump vertically while standing on a force plate with and without occlusal support (i.e. dentures). On the curve recorded by the force plate (1) reaction time (latency) (2) jump elevation time and (3) maximum kicking force were analysed. The reaction time, which is an index of physical quickness, was significantly prolonged when the subjects lost their occlusal support. This result suggests that reconstruction of occlusal support at a desirable mandibular position has significance not only for the restoration of masticatory function but also for the maintenance of physical exercise.

Dental Occlusion↗

PubMed1998

A possible association between paternal longevity and major depression among elderly men.

Ancestral longevity is sometimes thought to contribute to psychosocial well-being in late life. The present paper aims to examine if parental longevity is associated with mental health among the elderly. The age at death of the parents was compared between 68 patients with major depression who were aged 65 or over and 40 subjects of the same age range without any history of psychiatric disorder. Cox regression revealed that the fathers of the elderly men with unipolar depression died at a significantly younger age than those of the control group. Several hypotheses are advanced to explain this unexpected and intriguing association.

Age Factors↗

PubMed1998

The role of radical gastrectomy with systematic lymphadenectomy for the diagnosis and treatment of primary gastric lymphoma.

OBJECTIVE: We evaluated the therapeutic efficacy of radical gastrectomy for primary B-cell lymphoma of the stomach and attempted to identify patients who could be adequately treated with surgery alone. SUMMARY BACKGROUND DATA: Several recent gastric lymphoma reports have discussed the therapeutic benefits of various treatment strategies for stage IE and IIE lymphoma. However, few studies have been based on patients accurately staged by systematic lymphadenectomy with subsequent pathologic examination. METHODS: A retrospective study was performed to evaluate the survival and biologic behavior of lesions in 60 patients with gastric lymphoma who were treated by radical gastrectomy alone. Tumors were classified according to the histopathologic concept of mucosa-associated lymphoid tissue (MALT)-derived lymphoma. RESULTS: A low histopathologic grade was associated with a significantly lower incidence of nodal metastasis (p = 0.07) and less extensive infiltration of the gastric wall (p < 0.005) despite larger tumor size. A 5-year survival rate of >95% was attained with surgery alone for MALT lymphoma and for true stage IE lymphoma diagnosed by pathologic examination of up to N2 lymph nodes routinely performed after radical gastrectomy. CONCLUSIONS: Surgery alone is adequate treatment for stage IE or pure MALT lymphoma, provided that the staging is performed after radical gastrectomy.

Adult↗