Biomedical subjects

T Morimoto

Publications and source records attributed to T Morimoto.

At least 235 records · Page 13Linked to original sources

PubMed1997

Bow Hunter's stroke caused by a nondominant vertebral artery occlusion: case report.

OBJECTIVE AND IMPORTANCE: Bow hunter's stroke is a consequence of vertebrobasilar insufficiency as a result of mechanical occlusion or stenosis of the vertebral artery at the C1-C2 level by head rotation. In most cases, a dominant vertebral artery is involved. No case of bow hunter's stroke as a result of mechanical occlusion of a nondominant vertebral artery has ever been reported. CLINICAL PRESENTATION: We describe a rare case of Wallenberg's syndrome caused by occlusion of a nondominant vertebral artery induced by head rotation. The patient complained of vertigo and paresthesia of the left face and the right extremities when he rotated his head 45 degrees or more to the right. INTERVENTION: Dynamic angiography revealed that the left vertebral artery was smaller than the right, terminated in a branch of the posteroinferior cerebellar artery, and was stretched and completely occluded at the C1-C2 level with the head rotated 45 degrees to the right. The right vertebral artery was normal when the head was rotated to either the right or the left. Three-dimensional enhanced computed tomography with the head rotated 45 degrees to the right revealed that the left vertebral artery was stretched and occluded by dislodgment between C1 and C2. Cerebral blood flow scintigraphy with head rotation demonstrated that blood flow was decreased in the lower portion of the left cerebellar hemisphere. C1-C2 posterior fixation was performed to prevent life-threatening neurological accidents. CONCLUSION: We emphasize that the diagnosis of bow hunter's stroke should be based not only on angiographic findings but also on hemodynamic studies with head rotation.

Aged↗

PubMed1997

Effectiveness of mammographic screening for breast cancer in women aged over 50 years in Japan.

The optimal age for effective screening of subjects for breast cancer by mammography in Japan was studied based on the results of two mammographic screening systems (systems I and II) in Tokushima Prefecture. System I consisted of visit screening using a bus equipped with a mammographic apparatus. System II consisted of central screening performed at Tokushima Health Screening Center. The examinees numbered 2,500 and 3,707 in systems I and II, respectively. There was a significant difference between the two screening systems in the age distribution of the examinees. The detection rates of breast cancer were 0.6% and 0.24% in systems I and II, respectively, which are 2-5 times higher than that (0.12%) obtained by conventional screening using physical examination alone. The detection rate increased especially in the sixth and seventh decades of life. The sensitivity of mammography screening was 93.3% in system I and 81.1% in system II. Higher sensitivity (100%) than that (73%) of screening by physical examination was obtained in women aged over 50. The proportion of stage I was 60% in system I and 66.7% in system II, compared with 32-65% in the United States and Europe. The rates of no nodal involvement were high, being 77.8% and 83.3% in systems I and II, respectively, compared with 57-71% in other countries. Breast-conserving therapy was applied to 18 of the 24 patients with breast cancer detected by the two screening systems. In addition, in Wolfe's classification of mammograms, the proportion of DY (mammary dysplasia) pattern was remarkably low, being 3.2% in the sixth decade and 0.8% in the seventh decade, compared with 16.6% in women aged 49 years. These results indicate that mammographic screening is effective in women aged over 50 years in Japan, as has been found in other countries.

Aged↗

PubMed1997

Effect of blood blow and haematocrit on the relationship between muscle venous PO2 and oxygen uptake in dog maximally contracting gastrocnemius in situ.

1. To clarify the limiting factors for peak VO2 (VO2,peak), we measured muscle venous PO2, (PVO2) and VO2,peak under various O2 delivery conditions (arterial O2 concentration x flow) via the alteration of blood flow and haematocrit (Hct) in anaesthetized dog gastrocnemius muscle (n = 11) stimulated by 1 Hz isometrically and tetanically. 2. Two levels of flow (high and moderate) were maintained by using a pump (150 and 100 mL/min per 100 g, respectively). Haematocrit was adjusted to 45 and 30% by isovolaemic haemodilution with dextran (MW 40,000). 3. The decrease in Hct induced a 31% decrease in O2 delivery (P < 0.05), a 9-12% decrease in PVO2, a 23% decrease in VO2,peak (P < 0.05) and a 12-14% increase in O2 extraction (VO2/O2 delivery) at both flow levels. The decrease in flow induced a 24-25% decrease in O2 delivery (P < 0.05), a 15-17% decrease in PVO2 (P < 0.05), a 9% decrease in VO2,peak (P < 0.05) and a 19-22% increase in O2 extraction (P < 0.05) at both Hct levels. 4. The results suggest that the limiting factor of VO/,peak, unrelated to O2 diffusion limitation (i.e. the change in the heterogeneity of VO2 to O2 delivery ratio among capillaries), due to lowering Hct may be different from that due to lowering blood flow in maximally contracting muscle.

Animals↗

PubMed1997

A study of gamma-aminobutyric acid (GABA) in amniotic fluid.

OBJECTIVE: The purpose of the study was to evaluate the role of gamma-aminobutyric acid (GABA), an inhibitory neurotransmitter, in amniotic fluid (AF) during fetal distress, because it has been reported that several neurotransmitters, e.g. norepinephrine, are affected by GABA. METHODS: AF was obtained during elective cesarean section (CS, n = 11) and cesarean section due to fetal distress without labor pain (FD, n = 7). Maternal and umbilical-cord blood, as well as the first urine of the neonates, also were collected. GABA, norepinephrine (NE), and epinephrine (EP) concentrations were measured using HPLC. RESULTS: The GABA concentration was higher in the AF than in either maternal or fetal circulation, or in the first urine of neonates. The GABA concentrations in the AF and in the first urine of neonates were significantly higher in the FD group than in the CS group (p < 0.05). Furthermore, significant positive correlations were observed between the NE and GABA concentrations and between the EP and GABA concentrations in the AF. GABA was produced in a time-dependent manner in cultured amnion cells. CONCLUSION: The highest concentration of GABA was found in the AF. The GABA in the AF appeared to be derived from both the amniotic membrane and the fetal urine. The increase in the GABA concentration in cases of fetal distress might be partially derived from the fetus via fetal urine. The positive correlations between the concentrations of GABA and those of NE and EP in the AF, suggest that GABA, NE, and EP might play important roles during fetal distress.

Adrenergic alpha-Agonists↗

PubMed1997

Cytoplasmic p53 polypeptide is associated with ribosomes.

Our previous finding that the tumor suppressor p53 is covalently linked to 5.8S rRNA suggested functional association of p53 polypeptide with ribosomes. p53 polypeptide is expressed at low basal levels in the cytoplasm of normal growing cells in the G1 phase of the cell cycle. We report here that cytoplasmic wild-type p53 polypeptide from both rat embryo fibroblasts and MCF7 cells and the A135V transforming mutant p53 polypeptide were found associated with ribosomes to various extents. Treatment of cytoplasmic extracts with RNase or puromycin in the presence of high salt, both of which are known to disrupt ribosomal function, dissociated p53 polypeptide from the ribosomes. In immunoprecipitates of p53 polypeptide-associated ribosomes, 5.8S rRNA was detectable only after proteinase K treatment, indicating all of the 5.8S rRNA in p53-associated ribosomes is covalently linked to protein. While 5.8S rRNA linked to protein was found in the immunoprecipitates of either wild-type or A135V mutant p53 polypeptide associated with ribosomes, little 5.8S rRNA was found in the immunoprecipitates of the slowly sedimenting p53 polypeptide, which was not associated with ribosomes. In contrast, 5.8S rRNA was liberated from bulk ribosomes by 1% sodium dodecyl sulfate, without digestion with proteinase K, indicating that these ribosomes contain 5.8S rRNA, which is not linked to protein. Immunoprecipitation of p53 polypeptide coprecipitated a small fraction of ribosomes. p53 mRNA immunoprecipitated with cytoplasmic p53 polypeptide, while GAPDH mRNA did not. These results show that cytoplasmic p53 polypeptide is associated with a subset of ribosomes, having covalently modified 5.8S rRNA.

Animals↗

PubMed1997

Osmoregulatory inhibition of thermally induced cutaneous vasodilation in passively heated humans.

We examined the effect of increased plasma osmolality (P(osm)) on cutaneous vasodilatory response to increased esophageal temperature (T(es)) in passively heated human subjects (n = 6). To modify P(osm), subjects were infused with 0.9, 2, or 3% NaCl infusions (Inf) for 90 min on separate days. Infusion rates were 0.2, 0.15, and 0.125 ml.min-1.kg body wt-1 for 0.9, 2, and 3% Inf, respectively, which produced relatively similar plasma volume expansion. Thirty minutes after the end of infusion, subjects immersed their lower legs in a water bath at 42 degrees C (room temperature 28 degrees C) for 60 min after 10 min of preheating control measurements. Passive heating without infusion (NI) served as time control to account for the effect of volume expansion. P(osm) (mosmol/kgH2O) values at the onset of passive heating were 289.9 +/- 1.4, 292.1 +/- 0.6, 298.7 +/- 0.7, and 305.6 +/- 0.6 after NI, 0.9% Inf, 2% Inf, and 3% Inf, respectively. The increases in T(es) (delta T(es)) at equilibrium during passive heating (mean delta T(es) during 55-60 min) were 0.47 +/- 0.08, 0.59 +/- 0.08, 0.85 +/- 0.13, and 1.09 +/- 0.12 degrees C after NI, 0.9% Inf, 2% Inf, and 3% Inf, respectively, which indicates that T(es) at equilibrium increased linearly as P(osm) increased. delta T(es) required to elicit cutaneous vasodilation (delta T(es) threshold for cutaneous vasodilation) also increased linearly as P(osm) increased as well as the delta T(es) threshold for sweating. The calculated increases in these thresholds per unit rise in P(osm) from regression analysis were 0.044 degree C for the cutaneous vasodilation and 0.034 degree C for sweating. Thus the delta T(es) thresholds for cutaneous vasodilation and sweating are shifted to higher delta T(es) along with the increase in P(osm), and these shifts resulted in the higher increase in T(es) during passive heating.

Adult↗

PubMed1997

Modulation of jaw muscle spindle discharge during mastication in the rabbit.

Discharges of jaw muscle spindles were recorded during chewing carrot from mesencephalic trigeminal nucleus (Mes V) in the awake rabbit to evaluate contribution of the muscle spindles to the development of complete sequences of masticatory movements. The Mes V spindle units were divided into two types according to the maximum firing rates during mastication, with a dividing line at 200 Hz; high-frequency units and low-frequency units. Although both types of units fired maximally during the jaw-opening phase of chewing cycles, their firing rates and pattern varied according to three sequential stages of mastication (stages I, IIa, and IIb). The high-frequency units often increased firing before the start of mastication and built up firing in the first few chewing cycles. Their maximal firing rate was sometimes lower during stage IIa (chewing stage) than during stage I (ingestion stage) and stage IIb (preswallowing stage), although the jaw movements were greater in stage IIa than in other stages. The phase relationship of the firing to a jaw movement cycle in stage IIa was consistent in individual units. The low-frequency units did not build up activity before the onset of movements. They fired mostly during the jaw-opening phase, but the peak of firing did not necessarily coincide with the time of maximal opening. It was concluded that the difference in the firing pattern among masticatory stages may be ascribed to a stage-dependent modulation of both fusimotor activity and jaw movement pattern.

Animals↗

PubMed1997

Regulation of masticatory force during cortically induced rhythmic jaw movements in the anesthetized rabbit.

To examine the relationships between masticatory force, electromyogram (EMG) of masticatory muscles, and jaw movement pattern, we quantitatively evaluated the effects of changing hardness of a chewing substance on these three variables. Cortically induced rhythmic jaw movements of a crescent-shaped pattern were induced by electrical stimulation of the cerebral cortical masticatory area in the anesthetized rabbit. The axially directed masticatory force was recorded with a small force-displacement transducer mounted on the ground surface of the lower molars. EMGs were recorded from the masseter and digastric muscles simultaneously with jaw movements. Five test strips of polyurethane foam of different hardness were prepared and inserted between the upper molar and the transducer during the movements. The peak, impulse, and buildup speed of the masticatory force increased with strip hardness, whereas duration of the exerted force did not vary with strip hardness. The integrated activity and duration of the masseteric EMG bursts also increased with strip hardness. The integrated EMG activity of the digastric bursts was weakly related to strip hardness, whereas the duration was not. The minimum gape increased with strip hardness, but the maximum gape did not. The horizontal excursion of the jaw did not vary in a hardness-dependent manner, although it was greater in the cycles with strip application than in the cycles without strip application. Deprivation of periodontal sensation by cutting the nerves to the teeth reduced the buildup speed of the force, maximum gape, net gape, and horizontal jaw movements. The denervation also elongated the force duration and that of masseteric EMG bursts. However, the rate of the hardness-dependent changes in the above parameters did not alter after denervation. The latency of the masseteric EMG response to strip application was evaluated before and after denervation. In both conditions, it was > or = 6 ms in approximately 70% of the cycles and <6 ms in the remaining approximately 30%, which cannot be explained by a simple reflex mechanism. On the basis of the analysis of correlation coefficients, the masseteric integrated EMG seemed to be a good indicator of the peak and impulse of the masticatory force both before and after denervation. We conclude that periodontal afferents would be responsible for a quick buildup of masticatory force and that afferents other than those from periodontal tissue would contribute to the hardness-dependent change of masticatory force during cortically induced rhythmic jaw movements.

Animals↗

PubMed1997

Role of calcium conductances on spike afterpotentials in rat trigeminal motoneurons.

Intracellular recordings were obtained from rat trigeminal motoneurons in slice preparations to investigate the role of calcium conductances in the depolarizing and hyperpolarizing spike afterpotential (ADP and mAHP, respectively). The mAHP was suppressed by bath application of 1 microM apamin, 2 mM Mn2+, and 2 mM Co2+, and also by intracellular injection of ethylene glycol-bis(b-aminoethylenether)-N,N,N',N'-tetraacetic acid (EGTA), suggesting that the potassium conductance generating the mAHP is activated by Ca2+ influx. Mn2+ (2 mM) or Cd2+ (500 microM) reduced the ADP, whereas the ADP amplitude was increased by raising extracellular Ca2+ concentration from 2 to 8 mM by bath application of Ba2+ (0.5-5 mM) and by intracellular injection of EGTA. This would suggest that Ca2+ itself is likely to be the charge carrier generating the ADP. Focal application of omega-conotoxin GVIA (10-30 microM) suppressed the mAHP and enhanced the ADP, whereas focal application of omega-agatoxin IVA (10-100 microM) reduced the ADP amplitude without apparent effects on the mAHP. We conclude that Ca2+ influx through omega-agatoxin IVA-sensitive calcium channels is at least in part responsible for the generation of the ADP and that Ca2+ influx through omega-conotoxin GVIA-sensitive calcium channels contributes to the generation of the mAHP. Because of the selective suppression of the ADP and mAHP by omega-agatoxin IVA and omega-conotoxin GVIA, respectively, it is suggested that both calcium channels are separated geometrically in rat trigeminal motoneurons.

Animals↗

PubMed1997

Surgical treatment of early cancer of the proximal third of the stomach.

A retrospective study was conducted in search of an optimal surgical procedure for early cancer of the proximal stomach. The clinicopathological findings and survival data of 128 patients operated on during a recent period of 16 years were analyzed. Nodal metastasis was found in 12% of the patients and had a significant influence on the survival. It was more frequently observed in the undifferentiated type, regardless of the tumor size. Most metastases were found in the proximal paragastric nodes, and no metastasis was observed in the pyloric region or at the splenic hilum. These facts suggest that while the resection of paragastric nodes is advocated, neither total gastrectomy nor splenectomy is required simply for the purpose of lymphadenectomy.

Humans↗

PubMed1997

Dural arteriovenous fistula caused by jugular vein stenosis--case report.

A 32-year-old female presented with a dural arteriovenous fistula in the transverse-sigmoid sinus caused by stenosis of the left internal jugular vein. The feeding arteries were embolized, resulting in nearly complete disappearance of the fistula. This case supports the idea that dural arteriovenous fistula is an acquired lesion caused by intravenous hypertension.

Adult↗

PubMed1997

Orbital varix diagnosed by color Doppler flow imaging--case report.

A 66-year-old male presented with an angiographically occult orbital varix. Angiography and phlebography failed to demonstrate the lesion. Computed tomography angiography showed the varix, but not the vascular flow. Color Doppler flow imaging clearly demonstrated the well-defined varix with slow flow velocity, as well as the precise anatomical location. We recommend color Doppler flow imaging as one of the differential diagnostic tools for intraorbital vascular lesions.

Aged↗

PubMed1997

[Relationship between HLA-DRB1 genotypes and efficacy of oral type II collagen treatment using chicken cartilage soup in rheumatoid arthritis].

The correlation between the efficacy of type II collagen (C II) treatment of the rheumatoid arthritis (RA) and the existence of HLA-DRB 1 * 0405 allele was investigated in two groups of patients; the first group had HLA-DRB 1 * 0405 allele (the 0405 group) and the second had no such allele (the non-0405 group). Thirty-eight RA patients were given a chicken cartilage soup containing heat degenerated C II (the CII group) or a placebo soup (the placebo group) for three months. The 38 cases were composed of 11 cases in the 0405/C II group, 9 in the 0405/placebo group, 11 in the non-0405/C II group, 9 cases in the non-0405/placebo group. In the C II group, there was a significant increase in the anti-human C II IgA antibody serum titers (p = 0.003) and significant decrease in the anti-human C II IgG titer (p < 0.0001). The differences in the number of swollen and tender joints were statistically significant between the 045/C II and 0405/placebo groups (p of the swollen joints = 0.03, and p of the tender joints = 0.03), and between the 0405/C II and non-0405/C II groups (p = 0.006 and 0.01, respectively). We concluded that oral C II could have a therapeutic efficacy in RA patients with HLA-DRB 1 * 0405 allele.

Administration, Oral↗

PubMed1997

Comparison of C1-2 posterior fusion and decompression of the vertebral artery in the treatment of bow hunter's stroke.

Bow hunter's stroke results from vertebrobasilar insufficiency caused by mechanical occlusion or stenosis of the vertebral artery (VA) at the C1-2 level on head rotation. Surgical treatment of this condition may be chosen to avoid life-threatening accidents or because patients complain that conservative treatments such as verbal warnings or use of a neck brace to limit head and neck rotation are ineffective and thus restrict their lifestyle. Posterior fusion involving C1-2 has long been used to limit atlantoaxial rotational movements. However, it has the serious disadvantage that the range of head motion is severely reduced. Recently, decompression of the atlantoaxial portions of the affected VA has been used because it does not limit physiological neck movements. However, no long-term follow-up review of patients who have undergone this procedure has been conducted, and it is unclear whether this procedure always provides relief of symptoms. To answer this question, the results of C1-2 posterior fusion were compared with decompression of the VA for the treatment of bow hunter's stroke.

Aged↗

PubMed1997

Occurrence of severe vasospasm following intraventricular hemorrhage from an arteriovenous malformation. Report of two cases.

The authors present two rare cases of severe cerebral vasospasm following the rupture of arteriovenous malformations (AVMs). Computerized tomography revealed intracerebral hemorrhage in the thalamus in one case and in the putamen in the other, both accompanied by cast formation of intraventricular clots without radiological evidence of subarachnoid hemorrhage. Initial angiograms showed arterial narrowing of the bilateral internal carotid arteries in the supraclinoid portion but failed to demonstrate an arteriovenous shunt. Subsequent angiograms clearly demonstrated the existence of an AVM. Radiological features and possible mechanisms are discussed.

Adolescent↗

PubMed1997

Plasma concentration of matrix metalloproteinase 9 in gastric cancer.

BACKGROUND: The clinical significance of plasma concentration of matrix metalloproteinase 9 (MMP-9) was investigated in patients with gastric cancer. METHODS: Plasma was obtained from 138 healthy individuals and 70 patients who underwent gastrectomy for gastric cancer at Aichi Cancer Centre between August 1994 and July 1995. Plasma concentrations of MMP-9 were measured using a one-step sandwich enzyme immunoassay employing monoclonal antibodies. RESULTS: Patients with gastric cancer had plasma higher concentrations of MMP-9 than normal subjects. Postoperative concentrations of MMP-9 were lower than preoperative levels. In addition to patients with advanced cancer, those with early gastric cancer also exhibited higher mean values of and positivity rates for MMP-9 than healthy individuals. Preoperative plasma MMP-9 concentration correlated closely with Union Internacional Contra la Cancrum tumour node metastasis (pTNM) stage, severity of T, N and M classification, and tumour size. CONCLUSION: Plasma MMP-9 concentration can be used for detection of primary or recurrent gastric cancer, and for estimation of tumour extent.

Adult↗

PubMed1997

[Effect of aprotinin on bleeding during and graft patency after coronary artery bypass grafting].

The purpose of this study was to evaluate the effect of aprotinin on intraoperative bleeding and graft patency in 200 patients undergoing elective CABG. Patients were classified into three groups; patients receiving 1500000 KIU of aprotinin (group A), 300000 KIU of aprotinin (group B) and no aprotinin as the control (group C). The groups were almost the same as to age, sex, number of grafts and use of ITA. Intraoperative bleeding and reexploration were significantly decreased in group A compared with group B and C. All patients underwent coronary angiography between the 4th and 8th post-operative weeks. Graft patency was significantly decreased in group A (SVG: 90.4%, ITA: 91.1%) compared with group B (SVG: 95.3%, ITA: 100%) and C (SVG: 95.5%, ITA: 99.2%). Perioperative myocardial infarction increased in group A (3.7%). Aprotinin was effective in reducing intraoperative bleeding in CABG, but decreased early graft patency after CABG. It is suggested that aprotinin should not be used routinely in CABG unless a patient has bleeding tendency which is likely to be seen in emergency and redo surgery.

Aged↗

PubMed1997

[Umbilical cord blood transplantation for a patient with Diamond-Blackfan syndrome].

A five-year-old girl with Diamond-Blackfan syndrome received cord blood transplantation from an HLA-identical sibling. The patient showed pale face at birth, and was diagnosed to have Diamond-Blackfan syndrome. She had been treated with prednisolone (PSL), high dose of methylprednisolone, erythropoietin, and anti-lymphocyte globulin. Despite of these intensive therapies, erythropoiesis did not entirely improve, and transfusion of red blood cells had been required every third or fourth week until cord blood transplantation. Conditioning regimen consisted of thoraco-abdominal irradiation (TAI; 8 Gy), cyclophosphamide (CY; 50 mg/kg x 4), and anti-thymocyte globulin (ATG; 2.5 mg/kg x 4), Cyclosporin (CyA 3 mg/kg) was administered for the prophylaxis of graft-versus-host disease (GVHD). 4.14 x 10 (7)/kg of cord blood mononuclear cells were infused to the patient. White blood cell (WBC) and reticulocyte counts increased promptly, but recovery of platelet count was delayed. Skin GVHD (grade I) appeared on day +9, which responded to the administration of PSL (2 mg/kg). Chromosomal analyses of bone marrow cells for sex mismatch revealed complete chimerism on day +14, on day +28 and thereafter. Umbilical cord blood cells can be an alternative source of hematopoietic stem cells for allogeneic transplantation.

Child, Preschool↗