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Biomedical subjects

T Maehara

Publications and source records attributed to T Maehara.

At least 73 records · Page 4Linked to original sources
PubMed1998

Primary cardiac leiomyosarcoma growing rapidly and causing right ventricular outflow obstruction.

Leiomyosarcomas are extremely rare primary cardiac tumors. We report a rapidly growing primary leiomyosarcoma of the right ventricle, which obstructed the right ventricular outflow tract within one month after symptom onset in a 68-year-old man. Two-dimensional echocardiography was useful in diagnosing the extent and progression of the tumor. The tumor was surgically resected on an emergency basis, and the right ventricle and pulmonary artery were successfully reconstructed. Recurrence of the tumor on the right ventricle was observed, and the patient was overcome by sudden dyspnea and died three months after surgery.

Aged↗
PubMed1998

[Basic approaches in minimally invasive cardiac surgery (MICS) and its selection].

Recently, minimally invasive cardiac surgery (MICS) has been developed and popularized as a less stressful and less invasive technique in the field of cardiac surgery. There are eight currently available MICS approaches for open heart surgery. The optimum approach should be selected for each patient based on the results of preoperative examination including chest X-ray, computed tomography, and angiography. Between December 1996, when we first introduced MICS for mitral repair, and the end of November 1998, we performed MICS in 67 patients [excluding cases of MIDCAB]. These included 11 patients who received the Port-Access (Heartport, Inc.) system. Although no patients died in hospital stay, one died of cerebrovascular bleeding eight months later. All patients were evaluated in the outpatient department as being NYHA class I. In view of future technological progress, we expect that MICS will gradually become more widespread in cardiac surgery.

Cardiac Surgical Procedures↗
PubMed1998

[Relationship between imaging and pathological features and clinical factors in surgical cases of temporal lobe epilepsy].

The relationships between imaging, pathology and presumed causes in surgical cases of temporal lobe epilepsy (TLE) was studied. The subject was 62 patients (33 males and 29 females) who had had no attacks for more than one year after surgery. Average age at surgery was 28.2 +/- 9.9 years. Obvious neurological abnormalities were not found in these cases. MRI, PET and SPECT were performed. Hematoxylin and eosin was used for pathological judgement. Their medical charts were used to investigate their clinical factors. Although patients suspected of having encephalitis/meningitis had been hospitalized for 2 days to three months during childhood due to disturbance of consciousness with high fever and convulsion for several days; they were not diagnosed with encephalitis/meningitis at that time, and they suffered almost no handicaps other than epilepsy for several years following their comatose episodes. [Result] (1) On MRI, mesial temporal sclerosis (MTS) was detected in 48 of 52 patients (92%); 32 (62%) had high-signal intensity on T 2-weighted images; 31 (60%) had atrophy ¿23 (44%) had high-signal intensity on T 2 + atrophy¿; 5 (10%) had calcified lesions; and 2 (4%) had cystic lesions. On PET and SPECT, abnormal cerebral blood flow was noted in 33 of 36 (92%). (2) On pathological findings (61 cases), Ammon's horn sclerosis (AHS), tumors, gliosis in lateral temporal and meningeal inflammatory finding were detected in 42 (69%), 10 (23%) and 8 (13%) cases, respectively, whereas 2 showed no abnormalities. The 2 patients with normal pathology showed both high-signal intensity and atrophy on MRI. (3) The presumed causes of TLE were encephalitis/meningitis and/or suspected of these diseases in 15 patients (24%), injuries at birth in 5 (8%), and none in 42 (68%). The presumed causes in the 43 patients with AHS were encephalitis/meningitis in 11, injuries at birth in 3, and none in 29. Of the 15 patients in whom encephalitis/meningitis was estimated as the causes of TLE, only 6 (40%) had pathological evidence of meningeal inflammatory finding. Of the 42 patients in whom cause could not be determined, 2 had pathological evidence of meningeal inflammatory finding.

Adolescent↗
PubMed1998

[Results of resection of T3 primary lung cancer].

Primary resection for lung cancer was performed in 711 patients. Extensive surgery was performed in 99 T3 lung cancer (13.7%). Overall 5-year survival rate was 31.7%. Overall hospital mortality was 7.5%. Mean 5-year survival was 34.9% for patients with complete resection, 0% for patients with incomplete resection (p < 0.05). In patients with complete resection, mean 5-year survival was greater in patients with N0 (39.1%) than in patients with N1 (23.5%) or N2 (27.7%), but there was no statistically significant difference. There was also no statistically significant difference between adenocarcinoma and squamous cell carcinoma. Mean 5-year survival rate for patients with invasion of chest wall was 34.1%, with invasion of mediastinal pleura was 37.5%, with invasion of main bronchus was 58.3%, with interlobular invasion was 18.7%. Complete resection of T3 lung cancer may yield long time survival.

Adult↗
PubMed1998

[Evaluation of an ultrasonic cutting and coagulating system (harmonic scalpel) for performing a segmental and wedge resection of the lung].

In order to prevent the local recurrence of malignant tumors, it is important for surgeon to maintain a sufficient margin between the tumor and the edge at resection. For this reason we do not use an auto-suturing device, but instead use the ultrasonic cutting and coagulating system (HARMONIC SCALPEL, ETHICON ENDO-SURGERY Cincinnati, Ohio) whenever we perform either a segmental resection or a wedge resection of the lung. The subjects investigated consisted of 24 cases of lung tumors (15 metastatic tumors, 5 cases with primary lung cancer, 3 inflammatory tumors; and one benign tumor). The type of operation included 10 segmental resections and 14 wedge resections, with 21 open thoracotomies and 3 instances of thoracoscopic surgery, while 15 were single resections and 9 were multiple resections. Little bleeding was seen at the resection of the parenchyma and the vessels of the lung. However prolonged air leakage was observed in some cases that needed pleurodesis. The mean duration time of the surgery was 266 minutes, and the mean blood loss was 173 ml. The operative duration was a little longer than normal, because many cases were not first thoracotomies and some cases had multiple tumors. Nevertheless the amount of blood loss was slight. The longest post-operative period was two years and six months, no local recurrence has yet been seen in any of malignant cases. We consider this system to be very effective for performing a resection of the lung parenchyma because of the reduced blood loss and the apparent increased prevention of recurrence.

Endoscopy↗
PubMed1997

Quantitative regional cerebral flow measured by Tc-99M HMPAO SPECT in mood disorder.

Depressed (n = 14) and remitted (n = 9) patients with mood disorder, patients with depressive disorder not otherwise specified (NOS; n = 10) and normal subjects (n = 8) underwent non-invasive and quantitative measurement of cerebral blood flow using HMPAO and SPECT in a resting state. The mean and regional cerebral blood flow (CBF) in twelve ROIs were compared among the four groups and correlations between CBF and the depressive symptoms were studies. The CBF was computed using graphical analysis on the SPECT console after a bolus injection of Tc-99m HMPAO and radionuclide angiography. The depressed group had significantly lower mCBF in the bilateral hemisphere and rCBF in all except one of the ROIs than the NOS and normal group. Significant negative correlations were found between the Hamilton scale for depression and rCBF in the bilateral lower frontal cortex after correcting for age in the mood disorder. Parallel analysis using both the quantitative and semiquantitative methods revealed that the former provided more global reduction of CBF in mood disorder. These results indicate that mean and regional CBF measured by this non-invasive method contributes to the objective evaluation of depressive symptoms. Negative correlations between HRSD and rCBF in the frontal regions indicate that frontal hypoactivity is closely related to depressive symptoms.

Adult↗
PubMed1997

Surgical treatment of epilepsy from schizencephaly with fused lips.

BACKGROUND: Surgical treatment of schizencephaly with fused lips has been reported in few cases. In all of the previously reported cases, temporal lobectomy was selected as a major surgical treatment, except for one case with cortical resection. We present a case of direct resection of dysplastic walls of the schizencephalic cleft and the surrounding epileptic area. CASE: This 20-year-old college student with medication-resistant epilepsy was surgically treated by subpial cortical resection of the epileptogenic area around a schizencephalic cleft. Magnetic resonance imaging showed an unilateral schizencephalic cleft with fused lips in the right parietal lobe. Pathologic examination demonstrated dysplastic neurons in the epileptogenic cortex. Intraoperative electrocorticography clearly detected epileptiform discharges around the cleft, and the epileptogenic lesion was completely resected. He has been seizure-free for 1 year since the operation and he has no neurologic deficits. CONCLUSION: Subpial resection of the dysplastic cortex surrounding the cleft under the guide of electrocorticography is an effective and minimally invasive procedure for the treatment of schizencephaly.

Adult↗
PubMed1997

A monoclonal antibody that recognizes ganglioside GD1b in the rat central nervous system.

A monoclonal antibody (MAb), generated by immunizing BALB/c mice with homogenized bovine retinal tissue, was specific to ganglioside GD1b incorporated into liposome membranes. The antibody (MAb-5G6), classified as IgM, immunostained intensely the perikaryon and processes of motoneurons in the cranial motor nuclei and spinal cord. Spinal and trigeminal ganglion cells were also immunopositive to the MAb. Some fiber tract systems, such as the spinal and mesencephalic trigeminal tracts, the solitary tract and the posterior funiculus, were also immunoreactive to the MAb. These findings suggest that MAb-5G6 labeled specifically neurons with axons extending outside of the central nervous system as a peripheral nerve. The immunoreactive substances were visualized under electron microscopy just beneath the postsynaptic membrane and just inside the plasmalemma of the thick dendrites. No axon terminal was immunolabeled by the MAb. In the rat embryos, immunoreactivity to MAb-5G6 was found in the dorsal and ventral root fibers on the 15th embryonic day (E15). However, cell bodies of the spinal ganglion cells and motoneurons were immunostained by MAb-5G6 at a later stage (E20). The ventral commissure fibers in the floor plate of the spinal cord were transiently immunolabeled during E13-15.

Animals↗
PubMed1997

High prevalence of hantavirus infection in a group of Chinese patients with acute hepatitis of unknown aetiology.

In southwestern China, small but substantial numbers of patients with acute hepatitis were found without known hepatropic viral infections (hepatitis A, B, C, D or E, cytomegalovirus, Epstein-Barr virus) and were receiving no hepatotoxic drugs. Prevalence of antibodies, both neutralizing and specific immunoglobulin (Ig)M and IgG, to Hantaan virus were evaluated in a cohort of 136 such patients: 83 were of unknown aetiology, 53 had known viral hepatitis and 59 healthy subjects acted as controls. The results showed that the incidence of neutralizing antibody to Hantaan virus in acute hepatitis patients with non-hepatitis A-E virus infections (13 of 83) was significantly higher than in those with A-E infections (0 of 53, P<0.01). Furthermore, the incidence of specific IgM antibody to Hantaan virus in acute hepatitis patients with non-hepatitis A-E virus infections (6 of 83) was significantly higher than in those with A-E infections (0 of 53, P<0.05) and in healthy subjects (0 of 59, P < 0.05). These findings suggest that Hantaan virus may be an important agent, contributing, at least in southwestern China, to a significant number of the cases of acute hepatitis of unknown aetiology. This hantavirus infection resulted in an acute hepatitis, differing from the typical diseases: haemorrhagic fever with renal syndrome (HFRS) and hantavirus pulmonary syndrome (HPS).

Acute Disease↗
PubMed1997

Focal cortical dysplasia: appearance on MR images.

PURPOSE: To clarify the magnetic resonance (MR) imaging characteristics of focal cortical dysplasia (FCD). MATERIALS AND METHODS: The authors reviewed the MR images of 14 patients with FCD, which was confirmed with histologic examination. RESULTS: MR images exhibited FCD in 13 of the 14 patients. All lesions were localized to part of one hemisphere. T2-weighted images showed blurring of the gray matter-white matter junction and abnormal signal intensity in the white matter in 11 patients. T1-weighted images showed blurring of the gray matter-white matter junction in seven patients, broad gyri in nine, thick cortices in nine, abnormal sulci in 10, and focal enlargement of the overlying subarachnoid space or adjacent ventricle in eight. Surgical specimens exhibited disruption of cortical lamination without abnormal gyration in all patients, cytomegalic neurons in the cortex in three, disorganized bizarre glial cells in the cortex in seven, ectopic neurons or bizarre glial cells in the white matter in nine, and blurring of the gray matter-white matter junction in one. CONCLUSION: Blurring of the gray matter-white matter junction with abnormal signal intensity in the white matter on T2-weighted images is characteristic of FCD. The presence of ectopic neurons and bizarre glial cells, dysmyelination, and a reduction in the number of myelinated fibers might have been responsible for the MR imaging characteristics.

Adolescent↗
PubMed1997

Coexistence of ganglioglioma and cortical dysplasia in a patient with intractable epilepsy--case report.

An 8-year-old girl presented with coexistence of ganglioglioma and cortical dysplasia manifesting as intractable epilepsy. Preoperative computed tomography demonstrated a small calcified lesion in the left frontal lobe which was not diagnosed as ganglioglioma. Magnetic resonance imaging also failed to demonstrate positive evidence of ganglioglioma or cortical dysplasia. A calcified tumor and the surrounding epileptogenic areas were resected under electrocorticography (ECoG) guidance. Histological examination revealed coexistence of ganglioglioma and cortical dysplasia. The patient became seizure-free after surgery. Resection of the ganglioglioma together with the adjacent epileptogenic area under intraoperative ECoG guidance is important to achieve a successful surgical result in patients with ganglioglioma.

Brain Mapping↗
PubMed1997

Structural comparisons of cell organelles and nuclei in rat hepatocytes with three different fixation techniques.

The morphological properties of cell organelles and nuclei in rat hepatocytes were compared, when the hepatocytes were either chemically fixed in glutaraldehyde and osmium (GA-Os), chemically fixed only in osmium (Os-2h) or physically fixed with a microwave-irradiated osmium (Mw-Os) fixative for a short duration. Judging from the fine structure, the mitochondria and rER were best preserved after physical fixation; because of the smooth surfaces and regular open contours, but both organelles shrank in the two chemical fixatives. The Golgi complexes and peroxisomes of the hepatocytes were not markedly changed by any of the fixative procedures. However the lysosomes and sER were changed to some extent after physical fixation. In the nucleus, the two kinds of chromatins and the nucleolus were best preserved with physical fixation. In conclusion, physical fixation is a very simple and fast procedure that is convenient for routine electron microscopy if some attention is paid to the morphological changes.

Animals↗
PubMed1997

Three-dimensional imaging of cortical structure, function and glioma for tumor resection.

UNLABELLED: A three-dimensional brain imaging protocol with PET and MRI was used to visualize the cortical structure in relation to brain function and glioma infiltration to determine tumor resectability. METHODS: Sixteen patients with glioma had a PET scan with 11C-methionine to visualize tumor infiltration. The PET images were co-registered to the patients' own MRI reconstructed to the three-dimensional brain surface images to indicate the gyral structure and the extent of tumor infiltration. Thirteen patients, who bore tumors adjacent to the language or motor cortex, had H2 15O activation study to locate the eloquent cortex. The area of tumor infiltration was superimposed on the brain surface images together with the language and/or motor cortex. RESULTS: When a tumor was located within a single gyrus without influencing surface cortical gyrus pattern, the motor and language areas were identified morphologically by three-dimensional surface image alone. However, when the tumor caused swelling and deformation of cortical structure, functional mapping with H2(15)O activation technique was essential in locating them correctly. In such cases, the combined mapping of the facial motor area with oral movement and the language area with word repetition was the most useful method to identify the parasylvian structure in the dominant hemisphere. Total or near total resection of low-grade glioma in eight patients and the effective decompression of the active part of the malignant glioma in four patients was completed without causing functional neurological deterioration. CONCLUSION: The three-dimensional expression of cortical structure and function combined with PET glioma imaging with 11C-methionine is useful for radical resection of cerebral glioma.

Adult↗
PubMed1997

[Minimally invasive approach for mitral valve, aortic valve, and atrial septal defect surgery].

We successfully introduced minimally invasive cardiac surgery (MICS) to japan by performing thoracoscopic clipping of a patent ductus arteriosus in July 1992. MICS via a small right parasternal incision (Cosgrove procedure) was applied for one patients with severe rheumatic mitral stenosis, one with severe aortic regurgitation, and one with atrial septal defect (ASD). Mitral valve replacement (MVR), aortic valve replacement (AVR), and direct closure of the ASD were performed successfully by MICS for the the first time in Japan. All three patients required no blood transfusion and had no complications postoperatively, being discharged from hospital at 15, 13, and 9 days after their operations. MICS was satisfactory for mitral valve and ASD operations, but AVR by this approach took much longer than by standard midline sternotomy due to the poor surgical field obtained via the small right parasternal incision. A minimally invasive approach for surgery on the aortic valve and ascending aorta may require transection of the sternum or some other method. MICS has several advantages, including less trauma and pain, faster patient recovery, shorter ICU and hospital stays, a lower cost, and a better cosmetic outcome. Therefore, it is better for the patient when it is feasible. MICS should develop and be applied to more patients with cardiovascular disease in the future. Some of the standard cardiovascular operations may soon be replaced by MICS.

Adult↗
PubMed1996

The majority of T lymphocytes are polyclonal during the chronic phase of chronic myelogenous leukemia.

To clarify the extent of cell lineage involvement in chronic myelogenous leukemia (CML), we investigated the bcr gene rearrangement and clonality using the X-chromosome-linked restriction fragment length polymorphism (RFLP) methylation method in T lymphocytes and granulocytes. We examined the granulocyte and T-cell fractions from the peripheral blood of seven female patients with CML during the chronic phase; patients were heterozygous for RFLPs at the phosphoglycerate kinase (PGK) or the hypoxanthine phosphoribosyltransferase (HPRT) gene. RFLP-methylation analysis of granulocytes demonstrated a monoclonal pattern in six of the seven patients and a rearranged bcr gene in all seven patients. In contrast, T lymphocytes exhibited a polyclonal pattern in six cases; in one case, a faint band was observed following methyl-sensitive enzyme cleavage. The bcr gene analysis in T lymphocytes showed the germline in every case. Our results indicate that the majority of T lymphocytes are polyclonal during the chronic phase of CML and confirm previous reports based on glucose-6-phosphate dehydrogenase, cytogenetic, and bcr rearrangement analyses.

Adult↗
PubMed1996

Changes in lCBF, morphology and related parameters by fluid percussion injury.

We investigated the pathophysiological and morphological responses of anaesthetized rats to fluid percussion brain injury generated by an original midline fluid percussion injury device. Following different grades of trauma, lCBF was measured continuously in the right parietal cortex through a burr hole using laser Doppler flowmeter, and physiological parameters were monitored. Pathological changes also were evaluated microscopically. During the first 2 hours following trauma, we found four patterns of cerebral circulatory responses. Little measurable pathophysiological response occurred after percussion pulses of less than 1.33 atmospheres (atm). In animals subjected to pulses of greater than 4.30 atm, lCBF increased synchronously with blood pressure, and then both parameters decreased continuously until death. In animals subjected to pulses of 1.53 to 2.33 atm, trauma produced a transient increase in lCBF with no synchronous rise in blood pressure. In animals subjected to pulses of 2.70 to 3.87 atm, lCBF increased synchronously with blood pressure immediately following the injury, but had decreased markedly by 60 seconds and remained below the pre-injury baseline. Blood pressure recovered to baseline within 4 minutes of the injury. The transient increase in lCBF occurred within 5 seconds following percussion pulses of greater than 1.53 atm and appeared to be independent of the rise in systemic blood pressure. Apnoea occurred in animals subjected to pulses of greater than 1.53 atm, and the duration of apnoea and mortality rate correlated with the magnitude of the applied injury. A power decrease in the electroencephalogram post-injury and a delay in its recovery, both depended on the magnitude of the injury with few regional differences in the beta-2 band power. The distribution and extent of blood-brain barrier disruption and small haemorrhages also correlated with the magnitude of the injury. The number of neurons decreased significantly in both hippocampi by 2 weeks following moderate trauma. The four patterns of lCBF changes demonstrated in the present study, as well as the other responses to injury, may be useful for studying graded models of various diffuse brain injuries.

Animals↗
PubMed1996

Detection of c-myc oncogene amplification in a CML blastic phase patient with double minute chromosomes.

Double minute chromosomes (dmin) are relatively rare in leukemias. Cytogenetic analysis of blood cells from a woman with blastic phase chronic myelogenous leukemia (BC-CML) showed numerous dmin chromosomes and complex abnormalities including a Philadelphia (ph(1))-chromosome. Oncogene amplification in hematopoietic malignancies is also rare. Using PCR, we retrospectively investigated the extent of c-myc gene amplification in DNA extracted from stored blood smears from the patient. To qualify the PCR products, the beta-globin gene was used as the internal reference gene and it was co-amplified with the c-myc gene. The extent of amplified c-myc was about 6.8-fold. This finding suggests that the c-myc gene was amplified in dmin and that the gene amplification contributes to the progression to acute leukemia or rapid growth of leukemic cells.

Base Sequence↗