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T Maehara

Publications and source records attributed to T Maehara.

At least 109 records · Page 6Linked to original sources
PubMed1993

Neuronal pathway involved in nitric oxide-mediated descending relaxation in rat ileum.

The neuronal pathway that initiates nitric oxide-mediated descending relaxation in rat ileum was studied. The descending relaxation, which was suggested to be mediated by nitric oxide from our previous study, was selectively inhibited by 5-HT3 receptor antagonists. It was also inhibited by a nicotinic acetylcholine receptor antagonist. Exogenous 5-hydroxytryptamine (5-HT) and a selective 5-HT3 receptor agonist induced dose-dependent relaxation of ileal circular muscle. 5-HT-induced relaxation was selectively inhibited by 5-HT3 receptor antagonists. Nicotine also induced relaxation of the circular muscle, and its effect was inhibited by 5-HT3 receptor antagonists. 5-HT and nicotine increased the cyclic GMP content of the ileal tissue. Nitro-L-arginine inhibited the increases induced by both compounds in the cyclic GMP content, and a 5-HT3 receptor antagonist also inhibited that induced by nicotine. These results indicate that activation of a cholinergic neuron-5-HT neuron pathway initiates nitric oxide-mediated descending relaxation in rat ileum.

Animals↗
PubMed1993

Pharmacological characteristics of tachykinin receptors mediating acetylcholine release from neonatal rat spinal cord.

The pharmacological profiles of tachykinin receptors mediating the release of acetylcholine were examined in the isolated spinal cord of the neonatal rat. The acetylcholine release evoked by neurokinin A or acetyl-[Arg6,Pro9]substance P-(6-11) was depressed by the tachykinin antagonists, spantide and GR71251 at 10 microM, whereas the release evoked by substance P (0.3 microM) or neurokinin B (0.3 microM) was not affected by these tachykinin antagonists. Polymerase chain reaction amplification of rat spinal cord cDNA and sequence analysis revealed the presence of a substantial amount of fragments having sequences identical to that of the NK1 or NK3 receptor, but only a few having a sequence identical to that of the NK2 receptor. These results suggest that in the neonatal rat spinal cord a novel subtype of tachykinin receptor similar but not identical to the classical NK1 receptor is involved in tachykinin-evoked acetylcholine release.

Acetylcholine↗
PubMed1993

Posterior cranial fossa dural arteriovenous malformation with a varix mimicking a thrombosed aneurysm: case report.

Dural arteriovenous malformations (AVMs) in the posterior cranial fossa are relatively infrequent. Intradural haemorrhage is one of their specific complications. Angiographic demonstration of varices or aneurysmal structures is one of the hallmarks of severe cases. We report a patient with posterior cranial fossa dural AVM associated with a varix mimicking a thrombosed aneurysm on CT and MRI. Internal carotid and vertebral angiography failed to demonstrate an aneurysm, but external carotid injection revealed a dural AVM affecting the sigmoid sinus, and a varix. The AVM was completely eliminated by embolization. When a dural AVM is suspected clinically selective angiography should be performed to confirm the diagnosis even when CT or MRI do not show dilated vessels.

Cerebral Angiography↗
PubMed1993

Acquired epidermoid tumour in the thoracic spinal canal.

Acquired spinal epidermoid tumours are rare, and probably caused by skin fragments that have been transplanted by trauma or lumbar puncture. They almost always occur in the region of the cauda equina. We present an acquired spinal epidermoid tumour at the T 10 level, with pathological confirmation. A skin fragment had migrated to a site where it developed into a tumour.

Epidermal Cyst↗
PubMed1993

Postaortic left innominate vein: radiological assessment and pathogenesis.

Postaortic left innominate vein (PALIV) is a rare venous anomaly and the findings on plain chest radiographs have not been well described. Plain chest radiographs, CT and MR of nine adults known to have PALIV were reviewed. They all showed a high aortic arch, including four with a right-sided aortic arch and one with a double aortic arch, in postero-anterior radiographs, and seven showed curved shadows in the left upper mediastinum. On all lateral chest radiographs (n = 5), the superior retrosternal region was opacified by the high aortic arch. CT or MR images confirmed the aortic arch and/or innominate artery to be in that part of the retrosternal space, normally occupied by the left innominate vein, in all cases. Association of a curved shadow in the superior mediastinum with a high aortic arch on plain chest radiographs is therefore suggestive of, though not diagnostic for, PALIV. This entity was well documented by CT or MR and the radiological findings were considered to imply that developmentally PALIV is secondary to a high position of the aortic arch.

Adult↗
PubMed1993

Clonality in myelodysplastic syndromes: demonstration of pluripotent stem cell origin using X-linked restriction fragment length polymorphisms.

Restriction fragment length polymorphisms (RFLP) of the X-chromosome genes phosphoglycerate kinase (PGK) and hypoxanthine phorphoribosyltransferase (HPRT) were used to determine the clonal nature of myelodysplastic syndromes (MDS) in 22 patients. These included eight with refractory anaemia (RA), four with RA with ring sideroblasts (RARS), six with RA with an excess of blasts (RAEB), three with RAEB in transformation (RAEB-T), and one with chronic myelomonocytic leukaemia (CMML). Monoclonal X-inactivation patterns were observed in 19/22 patients. The remaining three cases, one each with RA, RARS and RAEB, were of polyclonal composition. Separated T-lymphocyte and granulocyte fraction analyses in six patients of the former cases revealed that T-lymphocyte as well as granulocyte fractions showed a monoclonal pattern of X-inactivation. These results support the view that the majority of MDS arise from a pluripotent stem cell capable of myeloid and lymphoid differentiation.

Adult↗
PubMed1993

Low incidence of seizures in patients with chronic subdural haematoma.

A total of 129 patients treated for chronic subdural haematoma were studied retrospectively to evaluate the incidence of seizures. None of 73 patients who were given prophylactic antiepileptic drug treatment developed seizures. Only two of 56 patients not given prophylaxis, developed early postoperative seizures. In these two, surgical technique was thought to be responsible. One patient developed complex partial seizures preoperatively. The incidence of seizures was therefore low, and similar to that previously reported for minor head injury. This study suggests that routine use of antiepileptic prophylaxis is not justified in patients with chronic subdural haematoma caused by minor head injuries, or other causes when there are no additional lesions present on CT scans.

Adolescent↗
PubMed1993

Dissociation of cyclic GMP level from relaxation of the distal, but not the proximal colon of rats.

The role of cyclic GMP (cGMP) in nonadrenergic, noncholinergic (NANC) relaxation of the longitudinal muscle of rat proximal and distal colon was examined. Electrical field stimulation (EFS) of preparations of longitudinal muscle from the proximal region significantly increased the cGMP content. Nitro-L-arginine inhibited this increase, and L-arginine reversed the inhibitory effect of nitro-L-arginine. Exogenously added nitric oxide (NO) and atrial natriuretic peptide (ANP) also increased the cGMP content of preparations of the proximal colon and induced muscle relaxation. From these and our previous findings suggesting an essential role of NO in NANC inhibition in the proximal colon, we conclude that the mechanism of NANC inhibition in the proximal region of rat colon involves NO and a cGMP generating system. In contrast, although exogenously added NO and ANP increased the cGMP content in the distal colon to the same extent as in the proximal colon, they did not induce any muscle relaxation. Vasoactive intestinal peptide (VIP), the most likely candidate as a NANC neurotransmitter in rat distal colon, did not increase the cGMP content in this region. Furthermore, no participation of NO in the NANC inhibitory response was observed in the distal region, but EFS increased the cGMP content significantly. Thus we conclude that relaxation of longitudinal smooth muscle in the distal portion of rat colon is not associated with a change in the cGMP content.

Animals↗
PubMed1993

Gender difference in the relationship between physical fitness and mental health.

The purpose of this study was to examine the relationship between physical fitness and mental health in men and women. Twenty-five students (12 men and 13 women) aged 19 to 23 years participated in this study as subjects with low life stress who did not participate in competitive sports. Their physical fitness level was determined according to VO2max test results obtained using a cycle ergometer, and their mental health status according to the results of psychological measurement using the Profile of Mood States (POMS) and Spielberger's State-Trait Anxiety Inventory (STAI). In the men, there was significant correlation of VO2max with each of the POMS subscores for tension (r = -0.61), depression (r = -0.61), fatigue (r = -0.60), and total mood disturbance (r = -0.59), as well as with STAI state (r = -0.66) and trait (r = -0.76) anxiety scores. On the other hand, no similar correlation was found in the women. These results suggest that the relationship between physical fitness and mental health in men differs from that in women.

Adult↗
PubMed1993

Scanning electron microscopic observations of the arachnoid granulations in monkeys with cerebrospinal fluid hypotension.

The changes in arachnoid granulations following the depletion of cerebrospinal fluid (CSF) were investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). In the normal tissue, the arachnoid granulations located at the inner walls of the superior sagittal sinus and the straight sinus had bulging protrusions of various sizes, as viewed with the SEM. With TEM, the outermost cells covering the surface of the arachnoid granulations had "giant vacuoles" in the cytoplasm. With CSF hypotension, the arachnoid granulations were smaller in size and the outermost layer of cells were thinner. The vacuoles in the outer layer were not developed. In the apical region of the individual arachnoid granulations with CSF hypotension, the arachnoid cells were densely clustered under the endothelial cells. With recovery to normal CSF pressure, the arachnoid cells appeared to protrude between the endothelial cells covering the apical portion of the arachnoid granulation.

Animals↗
PubMed1993

[Effect of combination therapy with sulbactam/cefoperazone and amikacin in the treatment of infectious diseases accompanied by hematological disorders].

We studied the efficacy and safety of a combination therapy with sulbactam/cefoperazone (SBT/CPZ) and amikacin (AMK) on severe infections in the patients with hematological disorders. We administered SBT/CPZ and AMK to 65 patients and analyzed the result of 57 patients, except for 8 drop outs, for evaluation. The overall clinical efficacy of this combination therapy was 64.9% (excellent in 15 patients, good in 22 patients). Thirty seven patients had sepsis and suspected sepsis. The efficacy was 67.6% in these patients. The rate of improvement in the cases (18 patients) with neutrophil counts under 500/mm3 during the administration among 28 patients who had not responded to prior antibiotic treatment was 67.9%. Diarrhea was found in 1 patient as an apparent side effect likely related to this drug regimen. It appears that combination therapy of SBT/CPZ and AMK was a useful regimen in the treatment of infectious diseases complicated with hematological disorders.

Adolescent↗
PubMed1993

[The assessment of multiple coronary artery bypass with bilateral internal thoracic artery grafts].

From 1982 to March 1991, 68 patients underwent coronary artery bypass grafting (CABG) using bilateral internal thoracic arteries (ITA). There were 62 males (91.2%) and 6 females (8.8%) ranging from 33 to 74 years old (mean 58.5 +/- 9.2). Thirty four patients had old myocardial infarction (OMI) and left main trunk disease was seen in 8.5% of the patients. The number of grafts was 2 to 6 per patient with an average of 3.2 +/- 1.0. In bilateral ITA grafting the combinations of RITA to LAD and LITA to LCX were most frequently used. There were no operative deaths except for one death which occurred while at the hospital. The patency rates for the RITA and LITA were 98.3% and 96.7%, respectively. Postoperative complications included reexploration for bleeding and heart tamponade in 9 patients, and low output syndrome in 7 patients. The frequency of blood transfusion decreased with the use of cell saver. Routine bilateral ITA grafting for multiple CABG is considered safe, with the early patency being relatively better than with saphenous vein grafting.

Adult↗
PubMed1993

[An innovative thoracoscopic surgery for patient ductus arteriosus--a Japanese first case report].

A five-year-old girl with patent ductus arteriosus (PDA) was successfully treated by thoracoscopic surgery, which was the first successful case in Japan. The operation was carried out under general anesthesia with usual endotracheal intubation. Short trocars were inserted through the left intercostal spaces to introduce a flexible video thoracoscope and adequate surgical instruments. After the ductus was carefully dissected and exposed, two titanium clips which were 11 mm in length were applied to interrupt the ductus completely. The continuous heart murmur of PDA was confirmed to disappear by an esophageal stethoscope. Postoperative course was uneventful and the patient was discharged on 6 postoperative day. No residual PDA shunt was revealed by doppler echocardiogram 8 months after surgery. The advantages of thoracoscopic surgery for PDA are: less postoperative pain and discomfort, early recovery and short hospital stay, and cosmetic preservation. Availability of smaller sized surgical instruments should allow this method indicated for smaller children or newborns with PDA.

Child, Preschool↗