Search PubMed⌕ Search

Biomedical subjects

T Maehara

Publications and source records attributed to T Maehara.

At least 91 records · Page 5Linked to original sources
PubMed1996

Signal hyperintensities on brain magnetic resonance imaging in elderly depressed patients.

In a retrospective brain magnetic resonance imaging study, we evaluated the prevalence and severity of signal hyperintensities in 30 elderly depressed patients and 30 controls matched for age, sex and cerebrovascular risk factors. A semiquantitative scoring method was used to grade findings in T2-weighted and proton density images. The elderly depressed patients had more extended periventricular hyperintensities, especially in the frontal region (depressed vs. control, 87 vs. 57%, p < 0.05), pons (33 vs. 7%, p < 0.05) as well as hyperintensities in the putamen and globus pallidus (57 vs. 27%, p < 0.05). The third ventricle was more dilated in depressed patients than controls after adjustment for age and cerebrovascular risk factors. The global index for ventricular enlargement was correlated significantly (r = 0.36, p < 0.05) with the severity of the hyperintensity in depressed patients. Our results indicate that these hyperintensities, especially in the frontal region, pons and lenticular nuclei, and the dilatation of the third ventricle play an important role, through the frontal-subcortical circuits, in mood regulation of elderly depressed patients.

Aged↗
PubMed1996

Surgical treatment of children with medically intractable epilepsy--outcome of various surgical procedures.

Outcome after temporal lobe resection, extratemporal resection, and corpus callosotomy was studied in 33 children aged 15 years or less with medically intractable epilepsy. Seizure-free control was achieved in 67% (6/9) of pediatric patients versus 67% (60/90) of adult patients receiving temporal lobe resection and in 33% (4/12) of pediatric patients versus 25% (7/28) of adult patients receiving extratemporal resection. Among patients suffering from drop attacks and generalized convulsive seizures, 42% (5/12) of pediatric patients versus 25% (6/24) of adult patients receiving corpus callosotomy became seizure-free. The most prominent histological diagnoses in temporal lobe resections were three cases of mesial temporal sclerosis, four of ganglioglioma, and two of neuronal migration disorders. Neuronal migration disorders were the main histology in extratemporal resections. Four of five patients with behavioral problems treated by corpus callosotomy exhibited improved hyperactivity and/or attention deficits. There was no surgical morbidity or mortality. The outcome of pediatric patients was at least as favorable as that of adult patients, and improvement of behavioral disturbances could be expected after surgery. Surgical treatment is an effective and safe procedure for children with medically intractable epilepsy.

Adolescent↗
PubMed1996

[A case report of concomitant UFT-E and CDDP against lung epidermoid carcinoma].

A 52-year-old male with the chief complaint of hemo-sputum was diagnosed after detailed examination as epidermoid carcinoma in the right upper lobe bronchus through the bifurcation. Thoracotomy revealed infiltration of carcinoma into the right main pulmonary artery and the superior vena cava, which could not be excised. Subsequent postoperative radiotherapy (69 Gy) showed NC. Then concomitant administration of UFT-E and a low dose of CDDP was started on an outpatient basis. After the third course of treatment (six weeks per course), a significant reduction was noted in the size of the carcinoma. Bronchoscopy revealed CR with the elimination of carcinoma to mere traces. Besides the myelosuppression seen at the end of the second course of treatment, which resulted in a two-week hospitalization for blood transfusion, no adverse effect prevented the patient from continuing the outpatient treatment courses and from returning to work. We consider that the treatment was very successful not only for its effectiveness in reducing the carcinoma but also for the high QOL achieved.

Administration, Oral↗
PubMed1996

Leukemic transformation in three patients with polycythemia vera. Analysis of the clinicopathological features and N-ras gene mutation.

Thirty-three patients were diagnosed as having polycythemia vera (PV) from 1973 to 1993 in our institution. Of these patients, three who had been treated with alkylating agents, progressed to acute non-lymphocytic leukemia (ANLL). Their physical findings and the laboratory data were similar to those patients who did not become leukemic. To investigate the association with leukemic evolution, we examined N-ras oncogene activation in those patients who progressed to acute leukemia. Point mutations in codons 12 and 13 were not always detected, suggesting that the N-ras gene did not influence occurrence of ANLL in our patients.

Adult↗
PubMed1995

Pharmacological characterization of GR82334, a tachykinin NK1 receptor antagonist, in the isolated spinal cord of the neonatal rat.

Pharmacological characteristics of [D-Pro9,[spiro-gamma-lactam]Leu10,Trp11]physalaemin-(1-11) (GR82334), a tachykinin NK1 receptor antagonist, and its effects on slow depolarizing responses of lumbar ventral roots evoked by primary afferent stimulation were examined in isolated spinal cord preparations of neonatal rats. GR82334 (1-3 microM) caused dose-dependent rightward shifts of the concentration-response curves for substance P, substance P methyl ester, delta-aminovaleryl [Pro9,N-Me-Leu10]substance P-(7-11) (GR73632) and neurokinin A in normal artificial cerebrospinal fluid and those for substance P methyl ester, GR73632 and neurokinin A in the presence of tetrodotoxin. GR82334 (10 microM) did not evoke gamma-aminobutyric acid (GABA) release from spinal cords of neonatal rats, whereas [D-Pro9,[spiro-gamma-lactam] Leu10,Trp11]substance P (GR71251), another tachykinin NK1 receptor antagonist, induced a significant increase in GABA release. GR82334 (1-3 microM) markedly depressed the slow depolarizing response of ventral roots, referred to as slow ventral root potential, evoked by the stimulation of the contralateral dorsal root or the ipsilateral saphenous nerve. In contrast, cyclo[Gln,Trp,Phe,Gly,Leu,Met] (L-659,877, 1 microM), a selective tachykinin NK2 receptor antagonist, did not depress the saphenous nerve-evoked slow ventral root potential and did not antagonize the action of neurokinin A to induce ventral root depolarization. The present results provide further evidence for the involvement of substance P, neurokinin A and tachykinin NK1 receptors in the primary afferent-evoked slow ventral root potentials.

Amino Acid Sequence↗
PubMed1995

Characteristics of substance P-evoked release of amino acids from neonatal rat spinal cord.

The characteristics of release of amino acids evoked by substance P from the neonatal rat spinal cord were examined. A hemisected spinal cord was continuously perfused and the release of amino acids into the perfusate was measured using high-performance liquid chromatography with a precolumn derivatization technique. Substance P (10 microM) evoked a significant increase in the release of aspartate, glutamate, GABA, glycine and taurine. The substance P-evoked release of these five amino acids was not reduced by Ca(2+)-free medium, but was blocked by [D-Pro4,D-Trp] substance P4-11 (10 microM). Perfusion of the spinal cord with low-Na+ medium (22 mM) induced a marked increase in the high-K+ (90mM)-evoked release of GABA, glutamate and glycine. In contrast, the substance P-evoked release of the five amino acids was significantly decreased by the low-Na+ medium. Similarly, perfusion of the spinal cord with low-Cl- medium (8 mM) increased the high-K(+)-evoked release of GABA and glycine, but decreased the substance P-evoked release of GABA, glycine and taurine. The substance P-evoked release of the five amino acids was dose-dependently blocked by d-tubocurarine (3-10 microM), whereas it was not blocked by tetrodotoxin (0.2 microM) or amiloride (30 microM). Compound 48/80 (10 micrograms/ml), a histamine-releasing agent on mast cells, evoked release of the amino acids from the spinal cord with characteristics similar to those of substance P-evoked amino acid release.(ABSTRACT TRUNCATED AT 250 WORDS)

Amiloride↗
PubMed1995

[The first case of Sjögren's syndrome with anti-Wa antibody].

A 42-year-old woman presented in 1992 with Raynaud's phenomenon, polyarthralgia and morning stiffness and next year developed xerostomia and xerophthalmia. Investigations revealed 20 mm/hr of ESR, positive test for RAPA (1 : 320), ANF (1 : 1280), anti-SS-A antibody and anti-Wa antibody, and positive Schirmer tear test. A biopsied specimen of minor salivary gland of lip showed lymphocytic infiltration around the ducts and fibrotic changes and a sialogram demonstrated diffuse dilatations of the peripheral ducts. Resulting from the data shown above, the diagnosis of Sjögren's syndrome was made. Anti-Wa antibody, which recognizes a 48 kD tRNA associated protein was identified in serum from a patient with systemic sclerosis by Yamagata in 1985. So far the antibody has been specific for systemic sclerosis, because all of six patients with anti-Wa antibody previously reported were diagnosed as having systemic sclerosis. However, we here described the first case of Sjögren's syndrome with anti-Wa antibody.

Adult↗
PubMed1995

[Empyema caused by perforation of metastatic colon cancer: a case report].

The patient was a 51-year-old female, underwent total gastrectomy for gastric cancer 6 years ago. She was admitted to a local hospital with the complaint of fever, the chest X-ray showed niveau in the left pleural cavity. Fecal material flowed out by drainage. Barium enema showed fistula of diaphragma from transverse colon. She was transferred to our hospital. Partial transverse colon resection and removal of the diaphragma fistula were performed. The colon tumor was histologically determined to be metastasis from gastric cancer with thoracic empyema.

Adenocarcinoma↗
PubMed1995

Vascular reserve in chronic cerebral ischemia measured by the acetazolamide challenge test: comparison with positron emission tomography.

PURPOSE: To determine the value of the acetazolamide challenge test with stable xenon-enhanced CT (Xe CT) for making therapeutic decisions in patients with chronic cerebrovascular disease. METHODS: We compared the Xe CT-measured acetazolamide response with various measures obtained by positron emission tomography. We performed both a positron emission tomographic scan and a Xe CT study in 11 patients with chronic cerebral ischemic diseases within a 1-week interval. An increase of cerebral blood flow after injection of acetazolamide was expressed as delta AT. Regional cerebral blood flow, cerebral oxygen metabolism, oxygen extraction fraction, and cerebral blood volume were measured with oxygen-15-labeled gases by positron emission tomography. RESULTS: In low-cerebral blood flow regions, decreased delta AT was accompanied by a significant elevation of oxygen extraction fraction and cerebral blood volume, compared with oxygen extraction fraction and cerebral blood volume in regions of normal delta AT. Plotting of regional data indicated that delta was significantly dependent on oxygen extraction fraction and cerebral blood volume. The area of decreased vascular reserve determined by the Xe CT image corresponded to the area of "misery perfusion" determined by positron emission tomography. CONCLUSION: The acetazolamide challenge test with Xe CT may offer an alternative to positron-emission tomography in detecting lesions with elevated oxygen extraction fraction and cerebral blood volume (misery perfusion) that result from chronic hemodynamic stress.

Acetazolamide↗
PubMed1995

[A case of hepatocellular carcinoma with bone metastasis responding to oral administration of UFT].

A 63-year-old male patient with a mass in the left chest wall was referred to our hospital. An osteoclastic area was found in the mass of the left 4th rib by computed tomography; the mass was hard and little movable. There was an irregular and poorly demarcated low-density area, 5 cm in diameter, in the liver anterior superior segment. Aspiration from the mass of the chest wall indicated adenocarcinoma (class V) and forecast of metastatic lesion. The titer of serum AFP showed an extremely high level of 1,100 ng/ml. According to these findings, the patient was diagnosed as having hepatocellular carcinoma with bone metastasis and treated by the administration of oral UFT (300 mg/day). Six months later, the mass in the left chest wall was completely eliminated, the size of the hepatic lesion changed to 2.5 cm, and the titer of AFP decreased to the normal range (8.4 ng/ml). Treatment of hepatocellular carcinoma with bone metastasis is often ineffective, but this is a rare case showing the clinical effectiveness of oral administration of UFT.

Administration, Oral↗
PubMed1994

Differences in relaxant effects of cyclic GMP on skinned muscle preparations from the proximal and distal colon of rats.

The relationship between the intracellular cyclic GMP content and relaxation of smooth muscle was studied in preparations from the proximal and distal colon of rats. Nitric oxide increased the cyclic GMP content of longitudinal muscle of both preparations to approximately the same extents. However, although nitric oxide at 0.03-10 microM induced concentration-dependent relaxation of the proximal segments, it did not induce any significant relaxation of the distal segments. The longitudinal muscle preparations were permeabilized by treatment with alpha-toxin to examine the relaxant effects of cyclic GMP on the contractile elements. Ca2+ induced contraction of the permeabilized muscle, the contraction consisting of a transient and subsequent tonic phases. Cyclic GMP (3-100 microM) reversed the tonic contractions induced by various Ca2+ concentrations (1-30 microM). The magnitude of the relaxant effect of cyclic GMP was significantly more in the proximal region than in the distal region. But in contrast to nitric oxide, cyclic GMP induced slight, but clear relaxation of the distal colon. The inhibitory effects of cyclic GMP on phasic contraction, like those on tonic contraction, were high in the proximal region and low in the distal region. These results suggest that the difference in the relaxant effects of nitric oxide in the proximal and distal longitudinal muscles is not due to a difference in extents of cyclic GMP generation, but mainly to a difference in the sensitivities of the contractile elements in the two regions to cyclic GMP.

Animals↗
PubMed1994

Clonality in chronic myeloproliferative disorders defined by X-chromosome linked probes: demonstration of heterogeneity in lineage involvement.

The restriction fragment length polymorphisms (RFLP) of the X-chromosome phosphoglycerate kinase (PGK) and hypoxanthine phosphoribosyltransferase (HPRT) genes were used to study the clonal basis of the chronic myeloproliferative disorders (CMPD). Analyses were performed on granulocyte and T-lymphocyte fractions obtained from 24 females; 13 had essential thrombocythaemia (ET), eight polycythaemia vera (PV) and three myelofibrosis with myeloid metaplasia (MMM). All 24 of these patients had monoclonal patterns of X-inactivation in the granulocyte fraction. For the T-lymphocyte fraction, non-clonal patterns of X-inactivation were observed in 8/13 patients with ET, 7/8 with PV and 1/3 with MMM, while the remaining eight subjects were found to have monoclonal patterns of X-inactivation. Our findings suggest that the majority of the CMPD in these patients originated from a relatively committed progenitor cell without the capacity to differentiate into T cells, and convincingly demonstrated heterogeneity of lineage involvement.

Adult↗
PubMed1994

Cyclic haemopoiesis at 7- or 8-day intervals.

We report a patient with severe anaemia and cyclic oscillations of reticulocyte and leucocyte counts, as well as serum iron (Fe), unsaturated iron-binding capacity (UIBC), ferritin, C-reactive protein (CRP) levels and temperature, at regular intervals of 7 or 8 d. After treatment with prednisolone, anaemia was corrected and the cyclic oscillations of these parameters ceased; whereas treatment with indomethacin, recombinant granulocyte-colony stimulating factor (G-CSF) and erythropoietin (Epo) were unsuccessful.

Adult↗
PubMed1994

Effects of RP 67580, a tachykinin NK1 receptor antagonist, on a primary afferent-evoked response of ventral roots in the neonatal rat spinal cord.

1. The pharmacological characteristics of RP 67580, a non-peptide tachykinin NK1 receptor antagonist, and its effects on a reflex response evoked by stimulation of primary afferent fibres, were examined in isolated neonatal spinal cord preparations of the rat. Potentials were recorded extracellularly from a lumbar ventral root and drugs were bath-applied in normal artificial cerebrospinal fluid (CSF) or in the presence of tetrodotoxin (TTX). 2. In normal artificial CSF, RP 67580 (0.1-0.3 microM) caused rightward shifts of the concentration-response curves for substance P (SP), neurokinin A (NKA) and substance P methyl ester (SPOMe), an NK1-selective agonist, with pA2 values of 7.25, 7.47 and 7.49, respectively. 3. In the presence of TTX (0.3 microM), RP 67580 also caused rightward shifts of the concentration-response curves for SPOMe and NKA. The pA2 value of RP 67580 against SPOMe (6.75) was significantly lower than that against NKA (7.22). RP 67580 (0.3-1 microM) did not cause a clear parallel shift of the concentration-response curves for SP, and it depressed the depolarizations induced by low concentrations of SP, but slightly potentiated those induced by high concentrations of SP. 4. RP 67580 (1 microM) did not depress the depolarizing responses to bombesin, L--glutamate, gamma-aminobutyric acid (GABA), thyrotropin-releasing hormone and muscarine. RP 67580 (1 microM), however, depressed the response to acetylcholine in the presence of atropine and the response to nicotine. RP 68651 (1 microM), the enantiomer of RP 67580 devoid of activity at tachykinin NK1 receptors, also depressed the response to acetylcholine in the presence of atropine. 5. RP 67580 (1 gAM) did not induce GABA release from the rat spinal cord.6. In the neonatal gerbil spinal cord, the antagonist effects of RP 67580 (0.3-1 JAM) against SPOMe were much less potent than in the neonatal rat spinal cord.7. In the rat spinal cord-saphenous nerve preparation, electrical stimulation of the saphenous nerve atC-fibre strength evoked a prolonged depolarization of the ipsilateral L3 ventral root (slow VRP).RP 67580 (0.1-1 JM) depressed the saphenous nerve-evoked slow VRP. In contrast, RP 68651 (0.3 JAM)had no effect on the slow VRP.8. The results of the present study indicate that RP67580 acts as a high affinity NK, receptor antagonist in the neonatal rat spinal cord, although it also possesses an antinicotinic action. This study further suggests the existence of a subpopulation of tachykinin NK, receptors that are activated by NKA and SPOMe, as well as by low concentrations of SP, and are sensitive to the antagonist action of RP 67580 in the neonatal rat spinal cord. This study also provides further evidence for the involvement of SP and NKA in the slow VRP evoked by C-fibre stimulation in the neonatal rat spinal cord.

Animals↗
PubMed1994

Three-dimensional structures of the neck region of the hamster spermatozoa in the caudal epididymis.

Three-dimensional structures of the capitulum and first mitochondria in the neck region of the hamster spermatozoa, were observed with transmission (TEM) and scanning electron microscope (SEM). Some capitula revealed a variable contour even in the caudal epididymis, but most finally developed to form a typical wagonette shape. The final shape of the capitulum is probably produced by the aid of apical protrusion of the right, pyramidal mitochondrium. The right and left first mitochondria were triangular pyramids in contour, while the dorsal and ventral ones were rod-like in shape. The mutual transformations between the capitulum and the first mitochondria are discussed in relation to the completion of the neck region.

Animals↗
PubMed1994

[A new video-assisted thoracoscopic surgical interruption of patent ductus arteriosus].

A new video-assisted thoracoscopic surgery was applied to patients with patent ductus arteriosus (PDA). After the ductus was carefully dissected and exposed, two or one titanium clips which were 11 mm in length were used to interrupt the ductus completely. Eight patients with PDA were successfully treated by the new technique between July 1992 and September 1993, which was the first successful series in Japan. Mean age was 4.3 years (range 1.7 approximately 6.7 years) and mean weight was 15.6 kg (range 10.0 approximately 24.0 kg). All patients had immediate complete PDA closure after the procedure which was proved to be successful by an esophageal stethoscope and color doppler echocardiogram. One patient had mild left recurrent laryngeal nerve dysfunction which was completely cured on 7th postoperative day. There were no other complications and the usual hospital stay was 4 or 5 days. No residual PDA shunt in all cases was revealed by color doppler echocardiogram during follow-up periods (range 3 approximately 12 months). 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 technique indicated for smaller children and premature infants.

Child↗
PubMed1993

[Radiotherapy for symptomatic osseous metastases: special reference to the analysis of patients achieved complete pain relief].

A total of 223 patients with 498 symptomatic osseous metastases treated by radiotherapy between July 1985 and June 1991 were retrospectively analyzed. Most sites, 409 (82%), were irradiated by conventional fractionation, while the remaining 89 sites were irradiated by dose-increment fractionation, low-dose short schedules or hyperfractionation. The total dose ranged from 5.4 to 74 Gy (mean, 41.4 Gy). Daily pain assessment was done by patients themselves on an 11-point scale, i.e., 10: pretreatment pain, 0: disappearance of pain following radiotherapy. In addition, improvement in performance status (PS) and the duration of complete pain relief were assessed. The following results were obtained. 1) Pain relief: Of 498 evaluated sites, complete pain relief and partial pain relief were achieved in 403 sites (81%) and 64 sites (13%), respectively. No significant difference was seen in the incidence of complete pain relief between weight-bearing bone and non-weight-bearing bone. Patients with PS 1, 2 or 3 were significantly superior to those with PS 4 in terms of complete pain relief (P < 0.05-0.001). The complete response rate increased in accordance with the dose delivered, i.e., 49% at 20 Gy, 70% at 30 Gy and 77% at 40 Gy, in all of the 498 sites irradiated; 60%, 86% and 95% of 403 sites, respectively, achieved complete pain relief. Regarding the fractionation regimens, dose-increment fractionation was superior to both conventional fractionation and low-dose short schedules in terms of complete pain relief rate. 2) Improvement of PS: Of 223 evaluated patients, PS was improved 1 to 3 steps in 162 (73%) at the completion of radiotherapy. The improvement rates of patients with PS 2 or 3 were significantly better than those with PS 4 (P < 0.025, 0.001). 3) Duration of complete pain relief: Of 288 appraisable sites, the recurrence of pain was recognized in 23 (9%) at intervals of 3 to 21 months (median, 5 months). On the other hand, the duration of pain relief was 16 to 79 months (median, 32 months) in 26 sites of survivors, and 1 to 28 months (median, 5 months) in 239 sites of decreased patients. The mean total dose was 48.5 Gy (TDF: 82) to 62 sites with a duration of pain relief of more than 13 months. 4) Re-irradiation to the same site: Of 14 sites retreated after initial complete response with a total dose of 30 to 50 Gy (mean, 48 Gy), 11 (79%) were in weight-bearing bone and 9 (64%) responded completely. 5) Patients with unsatisfactory pain relief (pain score > or = 6): Of 31 sites, 27 (94%) were in patients with PS 4, and 19 (61%) received a total dose below 30 Gy. 6) The 11-point scale for patient self-assessment of pain relief following radiotherapy was thought to be useful and easy to adopt in general clinics.

Adolescent↗