Biomedical subjects

T Maehara

Publications and source records attributed to T Maehara.

At least 55 records · Page 3Linked to original sources

PubMed2000

[Thoracoscopic lobectomy (non rib-spreading method): versus a video assisted lobectomy and a conventional thoracotomy].

We analyzed 33 thoracoscopic lobectomy (non rib-spreading method: NR) cases and 33 video assisted lobectomy (VA) cases and 49 posterolateral thoracotomy (PL) cases, regarding post-operative changes in the serum enzyme levels, operative bleeding, required analgesic treatments, changes in the respiratory function and other factors. Regarding the post/pre-operative ratio of creatinin phosphokinase, bleeding and analgesic treatment NR was showed significantly lower levels than the other two methods. Regarding the post/pre-operative ratio of vital capacity of the lung NR was significantly less than PL for every six months after the operation. With NR the mean number of dissected mediastinal nodes was 14.2 +/- 7.4 which was not significantly different from VA and PL. We thus concluded that NR caused less thoracotomic damage and especially far less restrictive damage to the respiratory function than both PL and VA. NR may also result in a better quality of life than VA and PL. The node dissection required for NR is also not considered to be inferior to that for PL because the number of dissected nodes for NR was not significantly different from that for PL. Therefore, in cases presenting with clinical stage I primary lung cancer NR is thus considered to be indicated in order to obtain an improved post-operative quality of life.

Aged↗

PubMed2000

[Endovascular neurointervention for cerebral aneurysm].

Embolization would have an advantage in the treatment of cerebral aneurysms by eliminating the need for craniotomy. The recent protocol of endovascular treatment for cerebral aneurysm is classified into two main categories; is parent artery occlusion and intra-aneurysmal embolization. For aneurysms with a broad neck and large sac, it is recommended to consider proximal arterial occlusion if tolerance is confirmed by cerebral blood flow study at the time of balloon Matas' test. Parent artery occlusion is a classical technique, but still mandatory and effective clinically. In patients who have aneurysms with a has well-defined neck and who are not good candidates for craniotomy, intra-aneurysmal embolization would be recommended as an alternative means of treatment. Care should be taken to prevent problems and complications, including careful catheter and guidewire manipulation. Careful selection of cases and appropriate pre-, intra-, and post-procedure patient management is essential. Since the clinical application of Gugliemi's detachable coil (GDC) started, the potential of endovascular treatment for cerebral aneurysm has changed considerably. Preliminary results of embolization using GDC suggest that endovascular treatment would offer marked improvement in the management of patients harboring cerebral aneurysms.

Embolization, Therapeutic↗

PubMed2000

[Endovascular neurointervention for intracranial dural arteriovenous fistula].

Dural arteriovenous fistula(DAVF) is an abnormal shunt within the dura matter or near the venous sinuses. Various congenital and idiopathic causes have been suggested, including such as venous sinus occlusion, trauma, surgery, and changes in hormone levels, but the exact etiology of the disease is unknown. The pattern of venous drainage seen on angiography was used as the basis for a classification of DAVF by Djindjian. Recent classification suggests that lesions that drain into the venous sinus or meningeal vein will behave only in a benign manner, whereas those that have subarachnoid venous drainage or alone or in addition will behave aggressively. Selection of treatment can be made from observation, carotid manual compression, transarterial or transvenous embolization, radiotherapy, or surgical intervention. The goal of treatment and consequently the techniques used, depends on the intensity of symptoms or the neurologic and, in particular, hemorrhagic risk posed by the type of venous drainage. The therapeutic decision depends also on the patient's general clinical status. Embolization can create a reduction of flow, which results in disappearance in symptoms and sometimes complete cure as seen at angiography. Complex DAVF must be treated with combined endovascular techniques plus neurosurgery or radiotherapy.

Arteriovenous Fistula↗

PubMed2000

[Functional hemispherectomy for children aged 2 years or less for the treatment of intractable epilepsy caused by cortical dysgenesis].

Thirteen children aged 2 years or less who had intractable epilepsy caused by cortical dysgenesis underwent functional hemispherectomy. The cerebral malformations were hemimegalencephaly in 8 cases and focal cortical dysplasia in 5 cases. Among 11 children who were followed for at least 6 months after the operation (6 to 54 months with a median of 26 months), 5 were seizure-free, 4 achieved > 90% seizure reduction, and 2 achieved 50-90% reduction. Ventriculo-peritoneal shunt was placed in 3 children with hemimegalencephaly. After hemispherectomy, all the children showed improvement in psychomotor development. Development was accelerated in 3 seizure-free children. In children with cortical dysgenesis, functional hemispherectomy may result in remarkable seizure reduction and steady developmental progress.

Age Factors↗

PubMed1999

Beta-1 (10-20 Hz) cortical oscillations observed in the human medial temporal lobe.

During wakefulness, signals from subdural electrodes attached to the basal and medial temporal lobes of adult human epilepsy patients revealed a rhythmic oscillation in the beta-1 frequency range (10-20 Hz). This activity was more prominent in the medial than in the basal temporal cortex. We also observed simultaneous oscillations in alpha frequency activity in the medial and the basal temporal cortices. In an eyes-open condition, the alpha oscillation was attenuated, while the beta-1 oscillation in the medial temporal lobe was not. This is the first report that the beta-1 oscillation is present in the human medial temporal lobe. Since we recorded this activity from within the limbic system, beta-1 activity may be an analog of the hippocampal rhythmic slow activity observed in some animals.

Adult↗

PubMed1999

Myelodysplastic syndromes with nephrotic syndrome.

It is sometimes reported that the immunological abnormalities in myelodysplastic syndromes (MDS) induce autoimmune disease (i.e., acute systemic vasculitic syndrome, chronic cutaneous vasculitis, polyneuropathy, relapsing polychondritis, and steroid-responsive pulmonary disorders). We investigated the clinical features of patients with MDS accompanied by nephrotic syndrome. We enrolled 125 patients with MDS who were admitted between January 1979 and May 1996 in this study. The renal function was assessed based on the laboratory data and the findings at the physical examination. The diagnoses of nephrotic syndrome and glomerular disease were established when 24-hr urinary excretion was more than 3.5 g and serum total protein was less than 6.0 g/dl, and when the 24-hr protein excretion was more than 1.5 g. Five patients (4%) had glomerular disease, and three (2.4%) had nephrotic syndrome. Of the five patients with glomerular disease, two had refractory anemia (RA), and three had chronic myelomonocytic leukemia (CMMOL). Three of the total 11 patients with CMMOL were diagnosed as having nephrotic syndrome. Among the CMMOL patients, those with nephrotic syndrome showed higher absolute monocyte numbers than did those without nephrotic syndrome (8830 +/- 4677/microl vs. 3061 +/- 2887/microl, P = 0.03). One CMMOL patient was treated with VP-16 and hydroxyurea. As the white blood cell count in this patient decreased, the 24-hr urine protein excretion and the serum tumor necrosis factor alpha level decreased. The relationship between nephrotic syndrome and CMMOL was not clear. High monocyte count and the serum cytokines in MDS patients may play a partial role in the evolution of glomerulonephritis, and CMMOL may be closely related to nephrotic syndrome.

Aged↗

PubMed1999

A new MRI technique for demonstrating the surface of the brain together with the cortical veins.

We assessed combining of surface-anatomy scanning (SAS) MRI and MR venography (MRV). We obtained SAS images with a half-Fourier single-shot fast spin-echo sequence, then MRV of the identical section with a two-dimensional phase-contrast technique. We then added the two sets of images. The combined images, which were obtained within 10 min, provided information about the surface anatomy and cortical veins. This simple technique is useful for demonstrating brain surface structures, especially in patients from whom one plans to excise a lesion.

Adult↗

PubMed1999

Successful surgical treatment of a dural arteriovenous fistula at the craniocervical junction with reference to pre- and postoperative MRI.

We report a 62-year-old woman who presented with a myelopathy at the lower thoracic level. Left vertebral angiography revealed a dural arteriovenous fistula (DAVF) at the craniocervical junction, draining into an anterior spinal vein. Below the T7 level, the spinal cord gave high signal on T2-weighted images and enhanced with Gd-DTPA. The patient was successfully treated by simple clipping of vein draining the DAVF. The abnormal signal intensity and contrast enhancement rapidly regressed, except in the conus medullaris. Regression of the parenchymal abnormality on serial MRI following treatment corresponded closely with postoperative improvement of neurological function.

Arteriovenous Fistula↗

PubMed1999

Enhanced gamma (30-150 Hz) frequency in the human medial temporal lobe.

We performed fast Fourier transformation power spectral analysis of the electrocorticogram in human medial temporal lobe during wakeful rest in six epileptic subjects. Compared with the electrocorticogram wave in the basal temporal lobe, which showed monotonic decline of spectral power across the frequency axis, the electrocorticogram wave in the parahippocampal gyrus was enhanced (or did not decline) in the gamma frequency range (30-150 Hz) in all subjects. Although it has been suggested that electrical oscillations of the hippocampus have functional roles in higher brain functions, namely learning and memory, the knowledge of hippocampal oscillations is largely limited to animal studies. The present results demonstrate that fast frequency oscillation is also present in the human medial temporal lobe, which has been reported in animal hippocampi. They also demonstrate the importance of recording very fast field potentials in human electrocorticograms. This fast oscillation is likely to play important functional roles related to learning and memory, possibly to induce long-term potentiation in the human medial temporal lobe.

Action Potentials↗

PubMed1999

Interictal hyperperfusion observed in infants with cortical dysgenesis.

We investigated increases of interictal regional cerebral blood flow (rCBF) in patients with intractable epilepsy caused by cortical dysgenesis. Using single photon emission computed tomography, we measured interictal rCBF of epileptic foci in 24 patients with cortical dysgenesis who achieved Engel Class I or II outcomes at least 1 year after surgical intervention. The patients included 14 males and ten females, ranging in age from 2 months to 34 years (mean 6 years and 5 months). In the interictal period, dysplastic areas showed hyperperfusion in four patients (17%), hypoperfusion in 15 (62%), and isoperfusion patterns in five (21%). Interictal hyperperfusion was found in four infants aged 3-4 months; three with focal cortical dysplasia and one with hemimegalencephaly. Our results suggest that interictal hyperperfusion may indicate the presence of an active epileptic focus in infants with cortical dysgenesis, but not in older children or adults with the same disorder. Given the risk of misinterpreting the normal side as hypoperfused, the phenomenon of interictal hyperperfusion in the epileptogenic area should be taken into account when diagnosing pediatric epilepsy caused by cortical dysgenesis.

Adolescent↗

PubMed1999

Diffusion-weighted MR imaging in multiple sclerosis: comparison with contrast-enhanced study.

OBJECTIVE: To assess the utility of cerebral diffusion-weighted MR imaging in the diagnosis of multiple sclerosis (MS) in comparison with contrast-enhanced T1-weighted imaging. METHODS AND MATERIALS: We reviewed T2-weighted spin-echo (SE), fluid-attenuated inversion-recovery (FLAIR), contrast-enhanced T1-weighted SE and echo-planar diffusion-weighted images (DWIs) obtained in seven patients with definite MS on nine occasions. RESULTS: In total, 94 plaques were demonstrated on T2-weighted SE and/or FLAIR images. A total of 13 of these plaques showed enhancement on contrast-enhanced T1-weighted images and hyperintensity on DWIs, and five non-enhancing plaques showed hyperintensity on DWIs. CONCLUSION: Diffusion-weighted imaging, which provides information based on pathophysiology different from contrast-enhanced imaging, is a potential supplementary technique for characterizing MS plaques.

Adult↗

PubMed1999

Surgical treatment of a case of early infantile epileptic encephalopathy with suppression-bursts associated with focal cortical dysplasia.

We report a surgically treated case of early infantile epileptic encephalopathy (EIEE) with suppression-bursts associated with focal cortical dysplasia. Tonic-clonic seizures followed by a series of spasms occurred about a hundred times a day at a few days of age. Interictal electroencephalogram (EEG) revealed a suppression-burst pattern that was predominant in the left hemisphere. Magnetic resonance imaging (MRI) suggested focal cortical dysplasia in the left prefrontal area. Combination therapies with antiepileptic treatments showed only partial efficacy. The patient underwent lesionectomy at age 4 months, after which he gradually showed psychomotor development and a decrease of spasms to 0-2 series daily. In cases of EIEE with focal cortical dysplasia, surgical treatment may have beneficial effects on both psychomotor development and seizure control.

Adrenocorticotropic Hormone↗

PubMed1999

Clinical outcome in three patients with myelodysplastic syndrome showing polyclonal hematopoiesis.

The clinical outcome of 3 myelodysplastic syndrome (MDS) patients with polyclonal hematopoiesis is reported. All patients were heterozygous for the phosphoglycerate kinase (PGK) gene. The presence of polyclonal hematopoiesis was determined by the X-chromosome-linked restriction fragment length polymorphism-methylation method using the PGK gene as a marker. The patients were initially diagnosed as having refractory anemia (RA), RA with ring sideroblasts (RARS), and RA with an excess of blasts (RAEB), respectively. Their pancytopenia persisted during the follow-up period of 11.4 years for the RA patient, 19.5 years for the RARS patient and 0.8 years for the RAEB patient. Although the RARS patient continues to be in good health, leukemic transformation occurred in the other 2 patients. A karyotype change from 46,XX to 45,XX,t(3;21),-7 was observed at the time of disease progression in the RA patient. The coexistence of a monoclonal MDS clone and normal bone marrow cells is thought to be the most probable reason for the polyclonal hematopoiesis of these patients.

Acute Disease↗

PubMed1999

Minimally invasive port-access coronary artery bypass grafting.

The Port-Access endovascular cardiopulmonary bypass system (Heartport, Inc., Redwood City, CA, USA), a recent technological innovation in minimally invasive cardiac surgery, was conducted successfully in coronary artery bypass grafting on a 69-year-old woman. The left internal thoracic artery was harvested through a limited left anterior thoracotomy and anastomosed to the left anterior descending coronary artery on a protected and arrested heart. Intraoperative coronary angiography confirmed good graft patency. The patient was discharged from the hospital in good condition 7 days after the operation. This was the first successful minimally invasive Port-Access coronary artery bypass grafting in Japan.

Aged↗

PubMed1998

Brain tumors in surgical neuropathology of intractable epilepsies, with special reference to cerebral dysplasias.

Surgical specimens from 30 patients (13 males and 17 females) with intractable epilepsy with brain tumors and allied lesions were histopathologically examined: 4 of nonneurogenic origin (1 angiolipoma with cortical dysplasia and 3 cavernous hemangiomas), 2 low-grade fibrillary astrocytomas, 1 pleomorphic xanthoastrocytoma, 3 pilocytic astrocytomas with nuclear polymorphism, 1 oligoastrocytoma, 9 gangliogliomas, 3 gangliogliomatous lesions combined with tuberous sclerosis-like dysplastic changes, and 7 undetermined lesions suspected of being mixed glioma, dysembryoplastic neuroectodermal tumor (DNT), or dysplasia. They were all located supratentorially: in the temporal lobe in 21, frontal lobe in 6, and parietooccipital lobe in 3. The age of onset was under 20 years in most patients. Some kinds of dysplasias, such as focal cortical dysplasia, glioneuronal heterotopia, and clustered neurons in the hippocampus and amygdaloid nucleus, were combined in 11 cases, especially those with age of onset under 10 years. Pilocytic astrocytoma-like features were seen in 5 of the gangliogliomas and 3 of the undetermined lesions, and DNT-like features in 2 of the former and 3 of the latter. Gangliogliomas, pilocytic astrocytomas, mixed gliomas, DNTs, and dysplasias may be closely inter-related in the development of intractable epilepsies of young patients.

Adolescent↗

PubMed1998

Endobronchial hamartoma treated by an Nd-YAG laser: report of a case.

Endobronchial hamartomas are only rarely encountered. They cause irreversible lung damage due to bronchial obstruction if not diagnosed early and treated properly. Among the various treatments for this rare disease, a surgical resection remains the most popular. We herein report a case of a 53-year-old man presenting with an endobronchial hamartoma which was successfully excised by laser irradiation via a rigid bronchoscope, along with a review of 113 patients with this disease reported in the literature.

Bronchial Diseases↗

PubMed1998

Differential effects of wortmannin on the release of substance P and amino acids from the isolated spinal cord of the neonatal rat.

1. Effects of wortmannin, an inhibitor of myosin light chain kinase, on the release of substance P and amino acids, GABA and glutamate, were investigated in the isolated spinal cord preparation of the neonatal rat. 2. Wortmannin at 0.5 - 10 microM depressed the release of substance P evoked by high-K+ (90 mM) medium from the spinal cord (IC50 = 1.1 microM). Wortmannin also depressed the high-K+ (70 mM)-evoked release of substance P from cultured dorsal root ganglion neurons of neonatal rats. In contrast, the high-K+ (90 mM)-evoked release of GABA and glutamate from the spinal cord was not affected by wortmannin (0.1 - 10 microM). 3. Upon stimulation of a dorsal root, a monosynaptic reflex and a subsequent slow ventral root depolarization were evoked in the ipsilateral ventral root of the same segment in the isolated spinal cord preparation. The magnitude of the slow ventral root depolarization was depressed gradually to about 70% of the control during the course of 30 min under wortmannin (1 microM). In contrast, the monosynaptic reflex was unaffected by wortmannin. 4. Immunofluorescent staining revealed that immunoreactivities of substance P and myosin II were colocalized at presynaptic terminals in the dorsal horn of the neonatal rat spinal cord. 5. The present results suggest that myosin phosphorylation by myosin light chain kinase may play a crucial role in the release of substance P, but not in the release of GABA and glutamate in the neonatal rat spinal cord. This may reflect a difference in the exocytic mechanisms of substance P-containing large dense core vesicles and amino acid-containing small clear vesicles.

Amino Acids↗

PubMed1998

A case of malignant peritoneal mesothelioma showed complete remission with chemotherapy.

A 71-year-old woman presented with an abdominal mass and ascites and was subsequently admitted to our hospital in June 1995. Further examination revealed that the mass was malignant and, as a result, surgery was indicated. However, the mass demonstrated widespread peritoneal dissemination, which therefore could not be resected, and pathological findings suggested a malignant peritoneal mesothelioma. The patient showed a remarkable response to combined chemotherapy with an accompanying intraperitoneal injection of cisplatin and etoposide and an intravenous injection of caffeine. However, owing to side effects, this regimen was discontinued. The patient was administered a combination drug of uracil and tegafur (UFT) in addition to intraperitoneal injection of cisplatin as an outpatient. By the 223rd day after surgery, the tumor mass and ascites had completely disappeared according to the CT. Hence chemotherapy was judged to have resulted in complete remission. Such a marked response to chemotherapy is rare in an advanced malignant peritoneal mesothelioma such as the present case. Eight months later, the tumor recurred in the pleura. Another regimen of chemotherapy with cisplatin and CPT-11 was performed. However, this treatment proved ineffective. The patient subsequently died of respiratory failure in January 1997 due to the mesothelioma. This is a case report of complete remission of malignant peritoneal mesothelioma by combined chemotherapy.

Aged↗