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Biomedical subjects

S Nitta

Publications and source records attributed to S Nitta.

At least 37 records · Page 2Linked to original sources
PubMed2001

Discrimination of ameloblastomas from odontogenic keratocysts by cytokine levels and gelatinase species of the intracystic fluids.

In the present study, we measured the levels of the cytokines and gelatinase species in the fluids of ameloblastomas and odontogenic keratocysts, and showed that ameloblastomas can be distinguished from odontogenic keratocysts by the use of these biochemical data. We found that interleukin (IL)-1alpha and IL-1beta levels in the intracystic fluids of ameloblastomas were significantly lower than those in the fluids of odontogenic keratocysts, while IL-6 levels in the fluids of ameloblastomas were significantly higher than those in the fluids of odontogenic keratocysts. On the other hand, no significant differences in tumor necrosis factor (TNF)-alpha levels of the fluids were detected between ameloblastomas and odontogenic keratocysts. An immunohistochemical study revealed that the staining intensity of IL-1alpha, IL-1beta and TNF-alpha in the tumor cells of ameloblastomas was significantly weaker than that in the epithelial cells of odontogenic keratocysts, while the staining intensity of IL-6 in the tumor cells was significantly stronger than that in the epithelial cells of odontogenic keratocysts. Gelatin zymography of the fluids showed that only a small amount of pro-MMP-9 was detected in ameloblastomas, while both pro-MMP-9 and the active form of MMP-9 were detected in 8 of 10 cases of odontogenic keratocysts. Thus, ameloblastomas can be distinguished from odontogenic keratocysts by measuring IL-1alpha and IL-6 levels, and gelatinase species in the fluids.

Adult↗
PubMed2001

Neuromuscular monitoring in myasthenic syndrome.

We describe the anaesthetic management of a 72-year-old man with myasthenic syndrome. Pre-operatively, he was treated with 3,4-diaminopyridine and showed a strong hand grip. During general anaesthesia with nitrous oxide and sevoflurane in oxygen, a mechanomyograph and two accelerographs were set up for the hands and left foot to monitor neuromuscular function. Insufficient force and acceleration of contraction with 1 Hz stimulation was observed in the hands. In the foot, the twitches produced by 1 Hz and train-of-four stimulation could barely be detected using the accelerograph, and the train-of-four ratio fluctuated between 70 and 100%. No neuromuscular blocking drugs were used during surgery. After discontinuation of sevoflurane, responses to train-of-four stimulation remained small, but a strong response to tetanic stimulation was observed, with post-tetanic facilitation. Extubation was successful, and recovery from anaesthesia was uneventful. Tetanic stimulation and post-tetanic facilitation are important in monitoring neuromuscular function in patients with myasthenic syndrome whose train-of-four responses are insufficient.

Aged↗
PubMed2001

Automatic detection and classification of abnormalities for artificial hearts using a hierarchical self-organizing map.

A hierarchical self-organizing map (SOM) has been developed for automatic detection and classification of abnormalities for artificial hearts. The hierarchical SOM has been applied to the monitoring and analysis of an aortic pressure (AoP) signal measured from an adult goat equipped with a total artificial heart. The architecture of the network actually consists of 2 different SOMs. The first SOM clusters the AoP beat patterns in an unsupervised way. Afterward, the outputs of the first SOM combined with the original time-domain features of beat-to-beat data are fed to the second SOM for final classification. Each input vector of the second SOM is associated with a class vector. This class vector is assigned to every node in the second map as an output weight and learned according to Kohonen's learning rule. Some experimental results revealed that a certain abnormality caused by breakage of sensors could be identified and detected correctly and that the change in the state of the circulatory system could be recognized and predicted to some extent.

Animals↗
PubMed2001

Difference in sensitivity to vecuronium between patients with ocular and generalized myasthenia gravis.

Patients with myasthenia gravis show sensitivity to non-depolarizing neuromuscular blocking drugs, but little is known about differences in this sensitivity between types of myasthenia. In 10 patients with ocular myasthenia gravis and 10 with generalized myasthenia gravis, twitch tension was monitored in the adductor pollicis muscle by supramaximal train-of-four stimulation of the ulnar nerve during anaesthesia with sevoflurane 2.5% and nitrous oxide 60%. After baseline measurement, an initial dose of vecuronium 10 microg kg(-1) was given. When the twitch height stabilized (maximum block after the first 10 microg kg(-1)), the next incremental dose of 10 microg kg(-1) was given and repeated until block, defined as [1-(first twitch/baseline first twitch)] x 100 reached 90%. Maximum block after the first dose of vecuronium in ocular patients was significantly less than that in generalized patients (median 51 vs 91%; P<0.05). Onset of block after the first dose of vecuronium was significantly slower in ocular than in generalized myasthenic patients (mean 300 vs 200 s; P<0.05). Doses required to attain a block of 90% or more were significantly higher in ocular than in generalized patients (median 20 vs 10 microg kg(-1); P<0.05). Clinicians should consider the type of disease according to the Osserman classification when using non-depolarizing neuromuscular. blocking drugs in patients with myasthenia gravis.

Adult↗
PubMed2001

Application of scanning acoustic microscopy for assessing stress distribution in atherosclerotic plaque.

Scanning acoustic microscopy (SAM) was equipped to assess the acoustic properties of normal and atherosclerotic coronary arteries. The SAM image in the atherosclerotic lesion clearly demonstrated that the sound speed was higher than that in the normal intima, and that the variation of elasticity was found within the fibrous cap of the plaque. Young's elastic modulus of each region was calculated and the finite element analysis was applied to derive the stress distribution in these arterial walls. In a case of normal coronary artery, the stress was dominant in the intima and the distribution was rather homogeneous and in a case of atherosclerosis, high stress was concentrated to the relatively soft lesion in the fibrous cap overlying lipid pool. SAM provides information on the physical properties, which cannot be obtained by the optical microscope. The results would help in understanding the pathological features of atherosclerosis.

Acoustics↗
PubMed2001

An approach to acoustic properties of biological tissues using acoustic micrographs of attenuation constant and sound speed.

OBJECTIVE: To develop a method for two-dimensional measurement of acoustic properties of biological tissue elements at the microscopic level for specimens with a thickness of approximately 10 microm. METHODS: The procedure was developed on the basis of mechanically scanned acoustic microscopic techniques in the frequency range of 100 to 200 MHz and the theory of interference phenomena. Various tissues and samples were prepared to evaluate the method and to interpret sound propagation properties. RESULTS: Tissues with high protein content, low water content, or both had a high attenuation constant and sound speed. The exponent n of attenuation against frequency was almost unity at the microscopic level, whereas it was greater than unity when the specimen thickness was greater. Sound speed dispersion was not observed. CONCLUSIONS: The method was shown to be reproducible, and the data were interpreted acoustically and pathologically with reference to tissue type and specimen thickness.

Acoustics↗
PubMed2000

Train-of-four fade and neuromuscular block in rats: a comparison between pancuronium, vecuronium, and rocuronium.

PURPOSE: To clarify the relationship between neuromuscular block and train-of-four fade and to investigate the causes of these drug-dependent differences, we compared the neuromuscular block and TOF fade after pancuronium, vecuronium and rocuronium. METHODS: In 24 anesthetized rats, the sciatic nerve was stimulated, and the twitch of left tibialis anterior muscle was recorded. After T1 (first twitch response) was kept constant at 95% block by administration of pancuronium, vecuronium, or rocuronium (n=8, in each), the TOF fade was measured when T1 block was decreased to 40% and 20%. In addition, using 24 phrenic nerve-diaphragm preparations, the fade was measured when the T1 block increased to 20% and 40% by titrating of either one of the three drugs (n=8, in each). RESULTS: In in vivo experiments, the fade produced by pancuronium was greater than that by vecuronium or rocuronium when T1 block was at 40% (81 +/- 9 vs 63 +/- 15 and 63 +/- 6%, respectively) and at 20% (66 +/- 13 vs 34 +/- 17 and 40 +/- 6%, respectively). In contrast, in in vitro experiments, the differences did not reach significant levels among the three drugs either at 20% (32 +/- 19 vs 33 +/- 10 and 32 +/- 17%) or 40% of block (62 +/- 29 vs 65 +/- 14 and 55 +/- 14%). CONCLUSIONS: For vecuronium and rocuronium, the results were similar in vivo and in vitro. For pancuronium, fade was greater in vivo. These results suggest that different neuromuscular blocking agent have different relationships between the fade and the block. In vitro results might not be the same as in vivo, possibly due to pharmacokinetic differences.

Acetylcholine↗
PubMed2000

Combined thoracic aortic or upper digestive tract resection for lung cancer and malignant mediastinal tumor.

OBJECTIVE: We studied possible indications and combined resection in patients with lung cancer and mediastinal tumors requiring combined thoracic aortic or upper digestive tract resection. METHODS: Ten patients with lung cancer and malignant mediastinal tumors (9 men and 1 woman aged 39 to 72 years; mean: 60.5) underwent combined aortic or upper digestive tract resection. RESULTS: Five--3 [corrected] with primary lung cancer, 1 with thymic cancer, and 1 with liposarcoma--, underwent combined aortic resection. In 2 each, lung cancer and malignant mediastinal tumor had infiltrated the thoracic aorta. The remaining case of lung cancer was complicated by aortic aneurysm in the distal arch. Cardiopulmonary bypass was conducted in 4, and selective cerebral perfusion in 2. Three patients are alive after 11, 22, and 61 months without disease recurrence. Those undergoing combined upper digestive tract resection all had lung cancer, with 4 having tumors infiltrating the esophagus or corpus ventriculi. The remaining patient had both lung and esophageal cancer. The patient treated with combined corpus ventriculi resection has survived 24 months and the patient treated with combined esophageal resection has survived 12 months without disease recurrence. The 1-year survival rate was 60%, 2-year 23%, and 3-year 23%. Prognosis was generally poor with the longest survival 13 months with N2 lung cancer. CONCLUSIONS: In combined resection due to malignant mediastinal tumor, T4N0-1 lung cancer, or diseases such as aortic aneurysm, prognosis can be expected to improve. Despite the often poor prognosis in T4N2 lung cancer, surgical intervention may be indicated to avoid complications due to tumor invasion and to lengthen survival and improve quality of life.

Adult↗
PubMed2000

Pulmonary multiple metastases of ovarian granulosa cell tumor 15 years after initial diagnosis.

We report a case of multiple pulmonary metastases occurring 15 years after an ovarian granulosa cell tumor was initially diagnosed. A 62-year-old woman undergoing left salpingo-oophorectomy for a granulosa cell tumor of the left ovary 15 years earlier presented with abnormal chest shadows. Computed tomography of the chest confirmed the presence of 3 well-defined nodular lesions, and Computed tomography of the abdomen and pelvis revealed a 3.5 x 2.5 cm partially solid, cystic pelvic mass. Left thoracotomy was conducted and tumors diagnosed a pulmonary metastases of a granulosa cell tumor. The pelvic mass was resected and infracolic omentectomy then conducted with total hysterectomy and right salpingo-oophorectomy including the adherent rectal segment. The pelvic mass proved to be a granulosa cell tumor. Adjuvant combination chemotherapy was started every 3 weeks and the woman has remained disease-free for 9 months.

Female↗
PubMed2000

Clinical assessment of unilateral pulmonary artery occlusion test with dobutamine infusion. Expansion of surgical indications in patients with primary lung cancer and impaired cardiopulmonary functions.

OBJECTIVES: We evaluated the possibility of expanding indications for pulmonary resection based on an assessment of the pressure-flow relationship in pulmonary circulation. METHODS: In 6 of 28 lung cancer patients whose total pulmonary vascular resistance index exceeded the threshold during unilateral pulmonary artery occlusion testing, we conducted unilateral pulmonary artery occlusion testing with dobutamine administration, followed by lung resection. We studied hemodynamics during testing and derived a new indication for pulmonary resection from the postoperative course. RESULTS: Cardiac output was 3.82 +/- 0.74 l/min before testing, 3.66 +/- 0.76 l/min during pulmonary artery occlusion testing, and 5.92 +/- 1.78 l/min during unilateral pulmonary artery occlusion testing with dobutamine infusion. The total pulmonary vascular resistance index was 890 +/- 350 dyne.sec.cm-5.m2 before testing, 1170 +/- 320 dyne.sec.cm-5.m2 during testing, and 800 +/- 160 dyne.sec.cm-5.m2 during testing with dobutamine infusion. Cardiac output increased (p = 0.014) during unilateral pulmonary artery occlusion testing with dobutamine infusion, and the total pulmonary vascular resistance index significantly decreased (p = 0.034). Of the 4 patients eligible for lobectomy, 2 underwent the procedure--one undergoing segmentectomy in which pulmonary metastasis was found during surgery and the other undergoing radiotherapy for cN2 disease with chest wall invasion. Of the 2 initially ineligible for lobectomy, one underwent partial pulmonary resection and the other underwent lobectomy because the total pulmonary vascular resistance index was less than 800 dyne.sec.cm-5.m2 during selective pulmonary artery occlusion testing with dobutamine infusion, indicating eligibility for lobectomy. No severe complications of cardiopulmonary function failure after surgery occurred in any of the 5 cases. CONCLUSIONS: Unilateral pulmonary artery occlusion testing with dobutamine infusion is useful in determining patient eligibility for pulmonary resection.

Aged↗
PubMed2000

Visualization of human umbilical vein endothelial cells by acoustic microscopy.

The morphology and acoustic properties of the human umbilical vein endothelial cells (HUVECs) were evaluated using a scanning acoustic microscope system. HUVECs were cultured for 4 days and exposed to the endotoxin for 4 h. The frequency of the scanning acoustic microscope was variable between 100 and 210 MHz. By changing the measuring frequency, ultrasonic amplitude and phase were measured and the quantitative value of attenuation was calculated. Before and after endotoxin stimuli, HUVECs were observed by scanning acoustic microscopy and the attenuation was measured. The acoustic images were successfully obtained to identify the outer shape of the HUVEC and the location of the nucleus in the cell. The attenuation of the nucleus is higher than that of the cytoplasm. The attenuation of the cytoplasm was increased and became inhomogeneous after endotoxin exposure. This finding would be related to the change of F-actin filaments, which is the main component of the cytoskeleton. Scanning acoustic microscopy is useful for assessing the cellular viscoelastic properties since it can detect both the morphological and acoustic changes without contacting the cellular surface.

Acoustics↗
PubMed2000

Evaluation of the inner-surface morphology of an artificial heart by acoustic microscopy.

The total artificial heart (TAH) is being developed for permanent replacement of the natural heart instead of heart transplantation. The need for detecting the material fatigue in the TAH is increasing in order to guarantee long-term use. In this study, the inner surface morphology of the TAH was evaluated by a specially developed scanning acoustic microscope (SAM) system operating in the frequency range of 100-200 MHz. The inner sac of our TAH consisted of polyvinylchloride coated with polyurethane, and the SAM investigations were performed before and after the implantations in goats. The amplitude images of the SAM demonstrated protein adhesion on the inner surface of the TAH after the animal experiment, and the phase images showed distortion of the wall with spatial resolution of 0.2 microm. These results suggest the feasibility of a high-frequency ultrasound for evaluating the material fatigue of TAH.

Animals↗
PubMed2000

[Type A behaviour pattern and hypercholesterolemia in elder patients].

To examine the relationship between type A behavior pattern and hypercholesterolemia, we recruited 109 primary hypercholesterolemic patients without treatment for hyperlipidemia (30 males and 79 females) and then classified them according to Maeda's questionnaire into two groups; type A group (16 males and 35 females, aged 73.1 +/- 8.7) and type B group (14 males and 44 females, aged 71.3 +/- 8.7). We studied serum total cholesterol, serum triglyceride and BMI. Serum total cholesterol was shown significantly higher in type A group than that in type B (233.0 +/- 22.8 vs 223.9 +/- 14.2 p < 0.01) and BMI lower (24.0 +/- 3.9 vs 25.4 +/- 3.9 p < 0.05), however, there was no significant difference in serum triglyceride between two groups (148.96 +/- 8.2 vs 134.0 +/- 48.8). Although there was no significant difference in BMI, serum total cholesterol was significantly higher in the women's group and in the 60s. This study suggests that type A behavior pattern is related to lipid metabolism, however we should take gender and age into consideration to study the relationship between type A behavior pattern and lipid metabolism.

Aged↗
PubMed2000

[Clonal rearrangement of intratumoral T-cell receptor beta-chain gene in two patients with thymoma accompanied by pure red cell aplasia].

We encountered two cases of thymoma accompanied by pure red cell aplasia and demonstrating clonal rearrangement of the T-cell receptor beta-chain gene (TCR-beta) in lymphocytes. Patient 1 was a 55-year-old man and Patient 2 was a 43-year-old woman. Both had severe anemia and mediastinal tumors. Bone marrow aspiration was performed and pure red cell aplasia diagnosed. Thymoma was the presumptive diagnosis for the mediastinal tumors, and extended thymectomy was performed. The post-operative diagnosis was invasive thymoma (spindle-cell type) in Patient 1 and non-invasive thymoma (mixed lympho-epithelial type) in Patient 2. The cell compositions (%) obtained with T-cell surface marker analysis were as follows: [table: see text] Southern blot analysis disclosed clonal rearrangement of TCR-beta genes in thymoma thymocytes from both patients.

Adult↗
PubMed2000

[A case of aneurysm of the ductus arteriosus in the adult].

Aneurysm of the ductus arteriosus in the adults is rare. A 60-year-old male with no symptoms was admitted to our hospital. 3 D-CT scans and aortograms indicated a diagnosis of aneurysm of the ductus arteriosus. Operation was done through median sternotomy with the aid of partial cardiopulmonary bypass. The saccular aneurysm was located between the aortic isthmus and the left pulmonary artery. The aneurysm was resected and closed a patch. The post-operative course was uneventful.

Aneurysm↗
PubMed2000

[Three cases of primary pulmonary malignant lymphoma].

Primary pulmonary malignant lymphoma is a rare disease that is thought to belong to a category of malignant lymphomas arising from mucosa- or bronchus-associated lymphoid tissue (MALT or BALT). We encountered 3 cases of primary pulmonary malignant lymphoma, Case 1: In a 51-year-old male, an abnormal shadow was detected in chest radiography in the right S9 after an operation for thyroid carcinoma. A right lower lobectomy was performed. The diagnosis was malignant lymphoma (marginal zone B-cell lymphoma). Immunohistochemical staining for IgM gave a positive result. Case 2: Multiple nodular shadows were noted in both lungs of a 55-year-old man after a bout of pneumonia. Video-assisted thoracoscopic surgery was performed, and the diagnosis was malignant lymphoma (marginal zone B-cell lymphoma). Gene analysis revealed rearrangement of a heavy chain gene. Case 3: An abnormal shadow was seen in the chest radiograph of a 60-year-old man. He was treated by right upper and middle lobectomy. The diagnosis was Hodgkin's disease, nodular sclerosing type. Chemotherapy was given after surgery and the patient is now alive without recurrence. As the pulmonary malignant lymphoma was difficult to diagnosepreoperatively, it was necessary to resect the mass for diagnostic purposes. The prognosis of a resected solitary lesion in the lobe was good. Therefore lobectomy was performed as the treatment of choice. Systemic chemotherapy is performed for the diffuse type of pulmonary lymphoma.

Humans↗
PubMed1999

Chaotic dynamics in circulation with Tohoku University vibrating flow pump.

For the development of a totally implantable ventricular assist system (VAS), we have been developing the vibrating flow pump (VFP), which can generate oscillated blood flow with a relative high frequency (10-50 Hz) for a totally implantable system. In this study, the effects of left ventricular assistance with this unique oscillated blood flow were analyzed by the use of nonlinear mathematics for evaluation as the whole circulatory regulatory system, not as the decomposed parts of the system. Left heart bypasses using the VFP from the left atrium to the descending aorta were performed in chronic animal experiments using healthy adult goats. The ECG, arterial blood pressure, VFP pump flow, and the flow of the descending aorta were recorded in the data recorder during awake conditions and analyzed in a personal computer system through an A-D convertor. By the use of nonlinear mathematics, time series data were embedded into the phase space, the Lyapunov numerical method, fractal dimension analysis, and power spectrum analysis were performed to evaluate nonlinear dynamics. During left ventricular assistance with the VFP, Mayer wave fluctuations were decreased in the power spectrum, the fractal dimension of the hemodynamics was significantly decreased, and peripheral vascular resistance was significantly decreased. These results suggest that nonlinear dynamics, which mediate the cardiovascular dynamics, may be affected during left ventricular (LV) bypass with oscillated flow. The decreased power of the Mayer wave in the spectrum caused the limit cycle attractor of the hemodynamics and decreased peripheral resistance. Decreased sympathetic discharges may be the origin of the decreased Mayer wave and fractal dimension. These nonlinear dynamic analyses may be useful to design optimal VAS control.

Analog-Digital Conversion↗