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Biomedical subjects

M Sato

Publications and source records attributed to M Sato.

At least 73 records · Page 4Linked to original sources
PubMed2004

[New surgical technique of pulmonary segmentectomy by ultrasonic scalpel and absorbable sealing materials].

We developed new surgical technique of pulmonary segmentectomy by ultrasonic scalpel to sever intersegmental pulmonary tissue and absorbable sealing materials to cover the cut surface of lung. This method is expected to preserve more anatomical lung volume than the segmentectomy with surgical stapler. Two cases of post surgical recurrent lung cancer, 3 cases of pulmonary metastasis and 4 cases of primary lung cancer were applied this technique to preserve function. Among 3 materials examined, best result was obtained with polyglycolic acid felt (PGAF:Neoveil). PGAF is a very soft and thin (0.15 mm depth) new absorbable material that is able to closely adhere to irregular sections of the lung with fibrin glue and effectively seals air leakage. Mean chest drainage period after surgery in 6 cases with PGAF was 3.3 days. Excellent lung expansion was obtained immediately after the surgery and PGAF was disappeared completely on chest CT within 1 year. Although the possible superiority of this method is suggested in the present study, further comparative study is necessary to clarify the advantage of this new technique.

Absorbable Implants↗
PubMed2004

[Leaflet extension technique in a congenital aortic valve regurgitation].

A 17-year-old boy who was diagnosed as congenital aortic valve regurgitation underwent the leaflet extension technique in 3 aortic leaflets using glutaraldehyde-preserved autologous pericardium. Intraoperative transesophageal echocardiography and postoperative cardiac catheter revealed grade I regurgitation and the patient has been doing well for more than 4 months after the surgery. The leaflet extension technique is considered to be an acceptable surgical treatment for aortic valve disease especially in young patients to whom valve replacement or Ross procedure might not be suitable. A careful long-term follow-up will be necessary to evaluate the durability of the leaflet extension technique with autologous pericardium.

Adolescent↗
PubMed2004

[Novel strategy for thoracoabdomianl aortic aneurysm repair; intraoperative selective perfusion of the Adamkiewicz artery].

We report our method for delineating the Adamkiewicz artery using multidetector row computed tomography (MDCT) with selective perfusion using a distal perfusion cannula that is clinically available for off-pump coronary artery bypass (OPCAB). The tip of a distal perfusion catheter (Medtronic Quickflow, Minneapolis) designed for OPCAB was applicable for selective perfusion of the segmental arteries. The femoro-femoral venoarterial bypass was branched off into selective perfusion of the segmental arteries, using an independent roller pump and heat exchanger. Our method of visualization of the Adamkiewicz artery was MDCT scanning with injection of contrast medium directly into the proximal descending aorta: namely, "CT during aortography". Lower descending aorta to abdominal aorta (the range involving the aneurysm) was scanned in a cephalad-to-caudal direction using a detector collimation of 4 x 1.25 mm with a table speed of 9.4 mm/sec, pitch of 6, and image thickness of 1.25 mm. All images were reviewed on a workstation to investigate the continuity between the Adamkiewicz artery and its proximal segmental artery with paging, mulitplanar reformation and curved planar reformation. Distal perfusion cannulae of 2.0 mm in diameter were inserted into the respective intercostal arteries. 4-0 polyethylene sutures were placed to tourniquet the catheters. Segmental arteries were perfused with total flow of approximately 80 ml/min at a circuit pressure of 120 mmHg. Reattachment of the ninth intercostal arteries related to the Adamkiewicz artery was carried out. A total of 6 consecutive 6 patients with thoracoabdominal aortic aneurysm (TAAA) have undergone graft replacement by the methods described, since April 2002. All patients survived surgery without any neurological complications. This method is expected to minimize the ischemic time of the spinal cord and attenuate the reperfusion injury.

Aged↗
PubMed2004

[Primary right ventricular malignant fibrous histiocytoma; report of a case].

Primary malignant fibrous histiocytoma located in the right side of the heart is extremely rare. We reported a case with literal reviews. A 71-year-old woman was admitted of faintness due to hypotension and marked edema of her lower extremity. With no time she was deteriorated into cardiogenic shock. Echocardiography demonstrated a tumor like mass which occupied her whole right ventricular cavity. Emergency tumor resection was carried out because of her status. Histological and immunohistochemical studies revealed the tumor was malignant fibrous histiocytoma. She died of pulmonary failure on nineteenth day after surgery.

Aged↗
PubMed2004

Life threatening chronic expanding hematoma of the thorax.

A 73-year-old man presented with severe respiratory distress and systemic edema. Diagnosis of chronic expanding hematoma (CEH) was made through examination of past and present radiographic studies. A giant mass lesion with surrounding calcification occupying the left hemi-thorax on the chest was demonstrated via computed tomography on admission, and a chest X-ray from 8 years previously revealed evidence of tubercular pleurisy. The patient's condition deteriorated rapidly after admission, necessitating urgent operative resection of the mass. The mass consisted of fresh and organized blood and demonstrated a calcified fibrous capsule, findings that are consistent with the diagnosis of CEH. Although the patient's condition improved following operative removal of the mass, he was ultimately diagnosed with postoperative empyema secondary to bronchopleural fistula, necessitating additional surgery.

Aged↗
PubMed2004

Abdominal aortic aneurysm with left-sided inferior vena cava. Report of a case.

The combination of abdominal aortic aneurysms and congenital anomalies of the inferior vena cava and its tributaries, such as double inferior vena cava, left-sided inferior vena cava, circumaortic renal collar, and retroaortic renal vein, are very rare but of clinical importance to vascular surgeons since these conditions can increase the difficulty of aneurysm resection as well as the risk of venous injury and subsequent excessive bleeding. This report describes a case of an abdominal aortic aneurysm with a left-sided inferior vena cava, and reviews of the incidence, diagnosis, and treatment of these conditions.

Aged↗
PubMed2003

Magnetic resonance cholangiopancreatography on postoperative work-up in children with choledochal cysts.

This study aimed to assess the clinical usefulness of magnetic resonance cholangiopancreatography (MRCP) as a postoperative diagnostic tool in children with choledochal cysts. Magnetic resonance cholangiopancreatography was performed postoperatively in 19 patients and image quality was compared with that obtained by intravenous cholangiography spiral computed tomography (IVC-SCT). While the detectability by MRCP was inferior to that by IVC-SCT, MRCP highly (84.2%) depicted the anastomotic site together with the reconstructed bowel and intrahepatic bile ducts. Magnetic resonance cholangiopancreatography also clearly delineated the postoperative condition of pancreaticobiliary maljunction (PBM), residual distal common bile duct, common channel, and pancreatic duct. Since MRCP is noninvasive and requires neither radiation exposure nor a contrast agent, and is useful for detecting both anastomosis and pancreatico-biliary ducts around PBM, MRCP might be superior to IVC-SCT as an imaging technique for outpatient clinics performing long-term follow-up studies in children with choledochal cysts.

Anastomosis, Surgical↗
PubMed2003

Methamphetamine differentially regulates hippocampal glucocorticoid and mineralocorticoid receptor mRNAs in Fischer and Lewis rats.

Fischer 344 (F344) and Lewis (LEW) rats differ in physiological regulation of the limbic-hypothalamo-pituitary-adrenal (LHPA) axis, such that F344 rats exhibit greater LHPA axis responses to a variety of stimuli. Furthermore, LHPA axis activity has been implicated in the development of sensitization to abused drugs, and F344 rats exhibit greater behavioral sensitization to psychostimulants. Accordingly, we hypothesized that there may be some overlap between the neurobiological mechanisms that underlie these strain differences in LHPA axis activity and in behavioral sensitization to psychostimulants. We examined the effects of acute and repeated methamphetamine (4 mg/kg) treatments on the regulation of hippocampal glucocorticoid receptors (GR mRNA) and mineralocorticoid receptors (MR mRNA) in F344 and LEW rats. Our results showed that acute treatment with methamphetamine (MAP) does not alter the level of expression of GR or MR mRNA in both strains. However, repeated treatments with MAP decreased the expression of hippocampal GR, but not MR mRNA specifically in F344 rats. The same repeated treatments had no effect on either GR or MR mRNA in LEW rats. This selective MAP regulation of the level of expression of hippocampal GR mRNA in F344 suggests that these receptors may play a role in the development of behavioral sensitization to MAP in this strain. The lack of alteration in hippocampal GR mRNA in LEW rats suggests that plasticity of hippocampal GR may not be critical for the development of behavioral sensitization to MAP in this strain.

Absorptiometry, Photon↗
PubMed2003

Antioxidant property of metallothionein in fasted mice.

Metallothionein (MT) is a low-molecular-weight and sulfur-rich protein that is induced by not only heavy metals but also physiological stresses such as fasting and restraint stresses. Although MT plays a role as a radical scavenger and a regulator of metabolism of metals, the biological function of MT induced by fasting stress has not been elucidated. In this study, we investigated the antioxidative role of MT in fasted mice. In fasted mice, the lipid peroxidation level of the liver was elevated by 24-h fasting stress, and pre-induction of hepatic MT by Zn diminished hepatic lipid peroxidation. Although 24-h fasting stress induced MT synthesis in the liver, other antioxidants such as catalase, manganese-superoxide dismutase (Mn-SOD), and glutathione peroxidase (GSHPx) were not activated in the liver. Moreover, the hepatic MT level was still elevated by fasting stress after seven cycles of repetition of alternate fasting and feeding every 24 h, but the activities of catalase, Mn-SOD and GSHPx were unchanged. These results indicate that MT induced by fasting stress plays partly as an antioxidant.

Animals↗
PubMed2003

Gigantic jets between a thundercloud and the ionosphere.

Transient luminous events in the atmosphere, such as lighting-induced sprites and upwardly discharging blue jets, were discovered recently in the region between thunderclouds and the ionosphere. In the conventional picture, the main components of Earth's global electric circuit include thunderstorms, the conducting ionosphere, the downward fair-weather currents and the conducting Earth. Thunderstorms serve as one of the generators that drive current upward from cloud tops to the ionosphere, where the electric potential is hundreds of kilovolts higher than Earth's surface. It has not been clear, however, whether all the important components of the global circuit have even been identified. Here we report observations of five gigantic jets that establish a direct link between a thundercloud (altitude approximately 16 km) and the ionosphere at 90 km elevation. Extremely-low-frequency radio waves in four events were detected, while no cloud-to-ground lightning was observed to trigger these events. Our result indicates that the extremely-low-frequency waves were generated by negative cloud-to-ionosphere discharges, which would reduce the electrical potential between ionosphere and ground. Therefore, the conventional picture of the global electric circuit needs to be modified to include the contributions of gigantic jets and possibly sprites.

Journal Article↗
PubMed2003

Property of metallothionein as a Zn pool differs depending on the induced condition of metallothionein.

Metallothionein (MT) is a low-molecular-weight, cysteine-rich, heavy metal-binding protein with several putative physiological functions as a radical scavenger and a regulator of metabolism of Zn. Although the induction of hepatic MT by a wide range of stressors is a well-known phenomenon, little is known about the role of MT in stressful situations. Since MT regulates Zn metabolism, we investigated the differences between affinities of MT for Zn in various stressful conditions in this study. Divalent cadmium ions are capable of displacement of Zn from MT in vitro. Therefore, we assayed the binding of Zn to MT induced by various stimuli using in vivo administration of Cd. MT was induced by paraquat (PQ), a reactive oxygen generator, fasting stress and restraint stress. Apo-MT induced by them bound to Zn in vivo. Zn, which bound to MT induced by PQ, was displaced by the administration of Cd. However, Zn that had bound to MT induced by fasting stress and restraint stress was not displaced by Cd. Moreover, we assessed the in vivo affinity of Zn to MT induced by fasting stress under the condition of subchronic Cd exposure. Cd was administered to mice by subcutaneously implanted Alzet osmotic minipumps, which released constant amounts of Cd over a 14-day period. After 4 days, mice were fasted for 24 h and hepatic MT was examined. Interestingly, it was found that Zn had displaced Cd bound to MT. These findings indicate that the affinity of MT for Zn differs depending on the stimulus by which MT was induced. This is the first report on differences in the properties of MT depending on the stimulus used to induce MT.

Animals↗
PubMed2003

Washout studies of 11C in rabbit thigh muscle implanted by secondary beams of HIMAC.

Heavy ion therapy has two definite advantages: good dose localization and higher biological effect. Range calculation of the heavy ions is an important factor in treatment planning. X-ray CT numbers are used to estimate the heavy ion range by looking up values in a conversion table which relates empirically photon attenuation in tissues to particle stopping power; this is one source of uncertainty in the treatment planning. Use of positron emitting radioactive beams along with a positron emission tomograph or a positron camera gives range information and may be used as a means of checking in heavy ion treatment planning. However, the metabolism of the implanted positron emitters in a living object is unpredictable because the chemical forms of these emitters are unknown and the metabolism is dependent on the organ species and may be influenced by many factors such as blood flow rate and fluid components present. In this paper, the washout rate of 11C activity implanted by injecting energetic 11C beams into thigh muscle of a rear leg of a rabbit is presented. The washout was found to consist of two components, the shorter one was about 4.2 +/- 1.1 min and the longer one ranged from 91 to 124 min. About one third of the implanted beta+ activity can be used for imaging and the rest was washed out of the target area.

Animals↗
PubMed2003

Morphological studies on the extracellular structure of the midgut of a tick, Haemaphysalis longicornis (Acari: Ixodidae).

In the present study, morphological observations on the extracellular structures found on the apical surface of the midgut epithelium, known as the peritrophic membrane (PM) or glycocalyx, are described in Haemaphysalis longicornis females and larvae. These structures have been hypothesized to provide protection to the microvilli of epithelial cells of the digestive tract. Our aim was to determine whether the extracellular structures are important in the digestion of the blood meal and/or as a protection against infection or injury. The PM was detectable in the midgut of engorged larvae by electron microscopy, but not in engorged females. However, a PM-like structure, stainable with toluidine blue, was observed in females by light microscopy. From the results of confocal laser scanning and electron microscopic observations with wheat germ agglutinin (WGA lectin) staining for chitin of the PM, however, the structure was clearly recognized. The structure in the female is likely to be PM because staining with WGA lectin in the presence of GlcNAc indicates the presence of chitin and various morphologies of PM have been reported in insects and ticks. These results show morphologically that different types of PM-like structure are formed in larvae and females of H. longicornis.

Animals↗
PubMed2003

Observation of locked intrinsic localized vibrational modes in a micromechanical oscillator array.

The nonlinear vibrational properties of a periodic micromechanical oscillator array have been measured. For sufficiently large amplitude of the driver, the optic mode of the di-element cantilever array becomes unstable and breaks up into excitations ranging over only a few cells. A driver-induced locking effect is observed to eternalize some of these intrinsic localized modes so that their amplitudes become fixed and the modes become spatially pinned.

Journal Article↗
PubMed2003

Tissue engineering of the intervertebral disc with cultured annulus fibrosus cells using atelocollagen honeycomb-shaped scaffold with a membrane seal (ACHMS scaffold).

The objective of the study was to investigate the regeneration of intervertebral discs after laser discectomy using tissue engineering procedures. Annulus fibrosus (AF) cells from the intervertebral discs of Japanese white rabbits were cultured in an atelocollagen honeycomb-shaped scaffold with a membrane seal (ACHMS scaffold), to produce a high-density, three-dimensional culture for up to 3 weeks. Although the DNA content in the scaffold increased at a lower rate than that in the monolayer culture, expression of type II collagen and glycosaminoglycan accumulation in the scaffold were at higher levels than in the monolayer. The AF cells that had been cultured in the scaffold for 7 days were allografted into the lacunae of intervertebral discs of recipients (40 rabbits, 14-16 weeks old; average weight, 3.2 kg), whose nucleus pulposus (NP) had been vaporised with an ICG dye-enhanced laser. The allografted cultured AF cells survived and produced hyaline-like cartilage. Furthermore, the narrowing of the intervertebral disc space of the cell-containing scaffold insertion groups was significantly inhibited after 12 post-operative weeks.

Animals↗
PubMed2003

Vertebral arch reconstruction based on 90 degree rotational laminoplasty after removal of spinal cord and cauda equina tumours.

BACKGROUND: A variety of procedures for reconstructing the spine following the removal of spinal cord and cauda equina tumours have been developed to prevent postoperative spinal deformities and nerve entrapment. The purpose of this paper is to introduce a new reconstructive procedure based on rotational laminoplasty and to report preliminary results in a small series. METHOD: The trough is drilled at the border of the laminae and articular processes and the ligamentum flavum is resected on its cephalocaudal aspect, so the vertebral arch can be separated as a single mass. After tumour resection, the vertebral arch is removed en bloc with the laminae, and is rotated 90 degrees and placed on the articular facets and fixed using suture passing through holes drilled in the bone. FINDINGS: One man and six women underwent rotational laminoplasty following resection of spinal or cauda equina tumours. Operative exposure was good and permitted complete resection. Patients did well postoperatively from both spine-surgical and neurosurgical points of view. Computed tomography documented a bony union with preservation of widely patent spinal canal. INTERPRETATION: Rotational laminoplasty affords a satisfactory operative exposure for the resection of large, complex lesions. It creates a widely patent, stable spinal canal easily, without the need for special tools.

Aged↗
PubMed2003

Lumbar disc herniation associated with separation of the posterior ring apophysis: analysis of five surgical cases and review of the literature.

BACKGROUND: Separation of the posterior ring apophysis of an adjacent vertebral body can sometimes accompany lumbar intervertebral disc herniation. The condition can be both difficult to detect in conventional radiographs and is somewhat controversial to treat. Although there is general agreement on the frequent need for surgery, there is no consensus on the choice of operation. One procedure, posterior lumbar interbody fusion (PLIF), has never been examined for effectiveness. METHOD: Computed tomography (CT) either or with discography (CTD) was compared to plane radiographs and magnetic resonance imaging (MRI) for its ability to reveal the fragmentation. Five cases were identified and the severity of the condition evaluated using the Japanese Orthopaedic Association's Assessment of Treatment for Low Back Pain (JOA score). The fragments were removed by impaction with a shoe shaped device and posterior lumbar interbody fusion (PLIF) was performed using autogenous iliac crest bone. A second evaluation using the JOA score was performed after a 4 to 5 year follow-up. FINDINGS: CT identified the separation in all 5 cases while plain films showed the defect in two and MRI in none. JOA scores prior to surgery were between 5 and 19 (mean, 13) and between 25 and 29 (mean, 27.4) at follow-up. The scores represented a recovery of 80% to 100%t (mean, 89.4). INTERPRETATION: CT and CT discography (CTD) are the diagnostic tools of choice for detecting this condition. Posterior lumbar interbody fusion (PLIF) is an effective procedure for patients who have low back pain due to lumbar disc herniation accompanied by a separation of the posterior ring apophysis.

Adolescent↗