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Biomedical subjects

N Hashimoto

Publications and source records attributed to N Hashimoto.

At least 289 records · Page 16Linked to original sources
PubMed1997

[Analysis of factors related to microemboli in cases with internal carotid artery stenosis].

Transcranial Doppler ultrasound (TCD) has been used to detect microemboli in cases with extracranial internal carotid artery stenosis. However, the mechanism causing microemboli has remained unclear. The purpose of this study is to clarify clinical characteristics and circumstances associated with the genesis of TCD-detected microemboli. Ninety-one cases with more than 30% stenosis of the internal carotid arteries were studied. TCD monitoring was carried out for an hour at the ipsilateral middle cerebral artery of each case using a 2-MHz pulse-wave transcranial Doppler device, and high intensity transient signals were counted as microemboli. Digital subtraction angiography, magnetic resonance imaging (MRI) and single photon emission computed tomography (SPECT) were also performed in all cases. Microemboli were detected in 30 of 91 cases. Microemboli were significantly well detected in cases with a history of ischemic event and/or cerebral infarction recognized by MRI. Detection of microemboli had no relation to sex, age or clinical risk factors (hypertension, hypercholesterolemia, diabetes mellitus and smoke habituation). In contrast, detection of microemboli was significantly related to decrease in cerebral blood flow recognized by SPECT, severity of stenosis and wall irregularity of lesion recognized by angiography. Microemboli can be found in a significantly high percentage of these clinical conditions, which may be risk factors for embolic stroke caused by extracranial internal carotid artery stenosis.

Aged↗
PubMed1997

[Effects of eicosapentaenoic acid in patients with bronchial asthma].

Eicosapentaenoic acid (EPA) is composed of 20 unsaturated fatty acids and is similar to arachidonic acid. Epadel, the drug made from EPA, is reported not only to reduce levels of serum lipids, but also to have antiinflammatory and antiallergic effects. EPA may exert these effects via control of the production of prostanoids and leukotrienes. We studied the effects of EPA in patients with bronchial asthma who had hyperlipidemia. The patents were given EPA at 1800 mg/day and they recorded signs and symptoms in an asthma diary during a 2-week observation period and the 8 weeks during which they took the drug. Peak flow, leukotriene B4 concentration in urine, Leukotriene E4 concentration in urine, IgE level, total cholesterol level, and triglyceride level were measured before and after the 8 weeks of medication. Administration of EPA was associated with improvements in symptom score, therapeutic score, asthma score, and peak flow. EPA may be useful in patients with asthma complicated by hyperlipidemia.

Adult↗
PubMed1997

[Detection of microemboli by transcranial Doppler sonography after carotid endarterectomy].

Transcranial Doppler sonography (TCD), a non-invasive monitoring technique, has potential for detecting microemboli caused by the extracranial internal carotid artery. Many previous reports have shown that TCD-detected microemboli may be a risk factor for stroke. The main purpose of this study is to verify whether microemboli cease after carotid endarterectomy (CEA). TCD monitoring was performed in 43 cases before and after CEA. TCD monitoring was carried out for an hour at the ipsilateral middle cerebral artery of each case using a 2-MHz pulse-wave transcranial Doppler device, and high intensity transient signals were counted as microemboli. Microemboli were detected preoperatively in 10 cases (23.3%). Microemboli were not detected in any case immediately after CEA, in either the subacute stage (from 14 to 21 days after CEA) or in the chronic stage (more than 3 months after CEA). In the acute stage (from 3 to 7 days after CEA), microemboli were detected in three cases (7.0%). The rate of TCD-detected microembolic was always significantly reduced after CEA. TCD monitoring can be helpful in assessing the effect of CEA for prevention of stroke by removing the suspected source of microemboli.

Aged↗
PubMed1997

Detection of embolic signals during and after percutaneous transluminal angioplasty of subclavian and vertebral arteries using transcranial Doppler ultrasonography.

OBJECTIVE: Percutaneous transluminal angioplasty (PTA) is accepted as a safe and effective procedure for the treatment of stenotic arterial lesions of various sites. However, distal embolism may cause serious complications in the PTA of cephalic arteries. By monitoring embolic signals using transcranial Doppler (TCD) ultrasonography, we speculated regarding the safety and/or risk of PTA for vertebral and subclavian artery stenosis. METHODS: Twelve consecutive patients undergoing PTA for subclavian and vertebral artery stenosis of atherosclerotic origin were studied. All patients were refractory to initial medical treatment and were considered for PTA. During the PTA procedure, all patients were heparinized. Before, during, and after PTA, TCD monitoring was performed to detect embolic signals for 30 minutes at each time. After PTA, anticoagulant and antiplatelet therapies were continued in all patients. RESULTS: Before, during, and after PTA, a steady flow signal could be obtained from each vertebral artery monitored using TCD ultrasonography. No embolic signals were detected in any patient before angioplasty. During angioplasty, one embolic signal was detected immediately after balloon deflation in 1 of 12 patients. Several embolic signals were detected after the procedure in 6 of 12 patients, but thereafter embolic signals became less frequent in number. Three days after angioplasty, embolic signals were not detected in any patient. There were no serious complications caused by the PTA procedure. CONCLUSION: TCD monitoring may be a useful modality for detection of microemboli during and after PTA in the posterior circulation. We suspected that subclinical microemboli are released from the dilated vessels for 3 days after vertebral and subclavian PTA and that anticoagulant or antiplatelet therapies may prevent embolic complications after the procedure.

Aged↗
PubMed1997

Mechanism of intracranial rebleeding in moyamoya disease.

Intracranial hemorrhage is the major catastrophic event in the natural course of Moyamoya disease, and outcome of the patients with rebleeding is very poor. However, the mechanism underlying intracranial rebleeding is not well elucidated. We retrospectively analyzed 15 patients who bled two times or more among 46 bled patients with Moyamoya disease. The results indicated that there were two different types in the manner of rebleeding. One group consisted of seven cases, which bled two times or more at the same site than the original bleeding site. In four of these seven cases, a ruptured aneurysm was identified at the distal part of collateral vessel or on the major vessel. In the other three cases, no source of bleeding was identified. In all of these cases, rebleeding occurred within 2 months after the initial insult except for one case. Another group consisted of eight cases, which bled repeatedly but at different sites from the initial bleeding site. In any of these cases, neither aneurysms nor other vascular abnormalities were identified. In all of these cases, rebleeding occurred more than 2 months after the initial bleeding. The present result indicated that intracranial bleeding might occur as a result of rupture of a tiny aneurysm at the periphery of collateral vessels. These aneurysms may be blown out after initial bleeding. When they persist after the event, they may rupture again in a fairly short interval. In other cases, bleeding occur at different sites from the initial site. They are considered to be a result of ruptured weak Moyamoya vessels which are forced to act as collateral pathways and are under unusually increased hemodynamic stress.

Adolescent↗
PubMed1997

[Clinical study on azithromycin in 10% fine granules and 100mg capsules in the field of pediatrics].

Azithromycin (AZM), a new oral macrolide antibiotic, in 10% fine granules or 100 mg capsules was given to pediatric patients to treat various infections. The following results were obtained in our studies of AZM for its antibacterial activities against clinical isolates, its pharmacokinetics, its efficacy, and its safety. 1. MICs of AZM, erythromycin (EM) and clarithromycin (CAM) were determined against a total of 57 strains all at 10(6) cfu/ml. Among Gram-positive cocci, MICs of AZM ranged from 0.78 to > 100 micrograms/ml against Staphylococcus aureus (20 strains), from 0.05 to 0.1 microgram/ml against Streptococcus pyogenes (11 strains), and from 0.0125 to 3.13 micrograms/ml against Streptococcus pneumoniae (10 strains). These MICs were similar to those of the other macrolides. Among Gram-negative bacilli, MICs of AZM were 0.05 micrograms/ml against Moraxella subgenus Branhamella catarrhalis (1 strain), from 0.78 to 3.13 micrograms/ml against Haemophilus influenzae (9 strains), 0.78 micrograms/ml against Haemophilus parainfluenzae (1 strain) and 6.25 micrograms/ml against salmonella sp. (1 strain). These values were similar to or lower than those of the other macrolides. Against Mycoplasma pneumoniae, MICs of AZM were < or = 0.0008 micrograms/ml in three strains. One strain of M. pneumoniae showed tolerance to AZM at MIC 25 micrograms/ml. The other agents exhibited higher MIC than AZM against this organism. 2. Plasma samples were collected from five patients receiving fine granules and four patients receiving capsules for drug level determination. The patients received AZM at 10.0 approximately 16.3 mg/kg body weight once daily for 3 days. Drug concentrations in plasma at two hours after Day 3 dosing were in a range between 0.02 and 0.19 micrograms/ml for fine granules and were in a range between 0.11 and 0.42 micrograms/ml for capsules. 3. Urine samples were collected from four patients receiving fine granules and four patients receiving capsules. Drug levels were determined to be 3 micrograms/ml at post-treatment 48 hours for fine granules and post-treatment 72 hours for capsules. Urinary excretion rates of AZM in three patients on capsules lied in a range between 4.69 and 10.17%. 4. Effectiveness of AZM in fine granules was evaluated in 128 patients having a total of 19 different infections. AZM was rated "excellent" in 51 patients, "good" in 63, "fair" in 8, "poor" in 6, resulting in an efficacy rate of 89.1%. Effectiveness of AZM in capsular form was evaluated in 23 patients with five different infections. AZM was found "excellent" in 13 patients and "good" in 10, resulting in an efficacy rate of 100%. 5. AZM in fine granules eradicated 45 strains of 54 in 8 different bacteria. AZM in capsules eradicated 9 strains of 10 strains in 6 different bacteria. 6. As for adverse reactions, one patient complained of eruption, one vomiting, one loose stool, five diarrhea, when administered with fine granular form of AZM. One patient on AZM capsules experienced urticaria and vomiting. 7. As for abnormal laboratory changes, three patients were found with decreased WBC, seven with increased eosinophil, two with increased GOT and GPT, one with increased GPT. They were all on fine granular form of AZM. As far as abnormalities found in patients administered with AZM in capsular form, two showed decreased WBC, one decreased WBC along with increased eosinophil, and three increased eosinophil.

Adolescent↗
PubMed1996

Changes of expressions of phosphotyrosine phosphatases in rat hepatocellular carcinoma induced by 3'-methyl-4-dimethylamino-azobenzene.

Using rats with hepatocellular carcinoma induced by 3'-methyl-4-dimethylamino-azobenzene (3'-MeDAB), we evaluated the expression of a protein tyrosine phosphatase (PTPase) in the tumor region, non-tumorous region and control rat liver. The expression of SHPTP2 increased 4.1 fold (p < 0.05) in mRNA, 2.1 fold (p < 0.01) in cytosol fraction, and 5.1 fold (p < 0.05) in membrane fraction, respectively, at a protein level in the tumor region compared with control liver. The expression of other phosphatases, LAR, LRP, and PTPase1B, did not change significantly. SHPTP2 phosphatase activity in the tumor region from rats also increased compared with control, suggesting that an increase of this activity may parallel the expression of SHPTP2. This increase of expression of SHPTP2 may contribute to the progression of hepatocellular carcinoma in this rat model.

Animals↗
PubMed1996

Analysis of numerical aberrations of specific chromosomes by fluorescent in situ hybridization as a diagnostic tool in breast cancer.

BACKGROUND: Biopsy by fine-needle, aspiration has become a routine technique for the diagnosis of a dominant breast mass. In this study, fluorescent in situ, hybridization (FISH) analysis of interphase nuclei allowed the authors to detect genetic aberrations that are difficult to identify by conventional cytology. METHODS: To investigate ways of minimizing misdiagnosis of the cytology of breast tumors, and detecting genetic aberrations preoperatively, the authors performed FISH with specimens obtained by fine-needle aspiration biopsies of 106 primary breast tumors (78 primary breast cancers, 2 phyllodes tumors, and 26 benign breast tumors). Numerical chromosome aberrations were investigated using 3-color FISH performed with (peri)centromere-specific probes for chromosomes 1, 11, and 17. RESULTS: Sufficient materials for FISH analysis were obtained with aspiration biopsy from 98 of the 106 breast tumors (93.4%). None of the benign tumors nor phyllodes tumors showed evidence of aneusomy for any of the 3 chromosomes. However, 71 of the 74 breast cancers (95.9%) for which sufficient material was available demonstrated aneusomy of at least 1 of the 3 chromosomes tested. The FISH analysis also suggested a possible correlation between aneusomy of chromosome 17 and metastasis to regional lymph nodes (chi-square test = 7.78; P < 0.05). CONCLUSIONS: FISH analysis of fine-needle aspiration biopsies can be a practical and useful method for the preoperative diagnosis of breast carcinoma.

Biopsy, Needle↗
PubMed1996

Arteriovenous malformation associated with moyamoya disease.

The first case of a child with an arteriovenous malformation (AVM) associated with moyamoya disease is reported. The patient presented ischemic symptoms and underwent indirect bypass surgery on both sides when she was 5 years old. Four years later she suffered from headache, and a small AVM of the left frontal lobe associated with the moyamoya vessels was detected. Single photon emission computed tomography (SPECT) was performed at age 11 and demonstrated low local cerebral blood flow (CBF) in the left frontal lobe and right temporal lobe, although the revascularization after the bypass surgery seemed to be effective, as judged on pancerebral angiography. We feel that brain ischemia due to the moyamoya disease may have played a causative role in the development of the AVM.

Blood Flow Velocity↗
PubMed1996

Histological changes in brain tissue and vasculature after intracarotid infusion of organic solvents in rats.

Organic solvents, such as ethanol or dimethyl sulphoxide (DMSO), have been used in liquid embolic agents. To investigate the effects of these solvents on the cerebral blood vessels and cerebral tissue, we subjected Wistar rats weighing 250-300 g to internal carotid artery infusion of 0.2 ml diluted ethanol (10%, 40% or 70%) or anhydrous DMSO (100%). Some rats were sacrificed 5 min after the infusion and the remainder at 10 days. Rats injected with ethanol at high concentration or DMSO showed extensive exudation of Evans blue at the site of injection 5 min after infusion, together with full-thickness necrosis of the wall of vessels and swelling of brain cells. In contrast, rats injected with 10% or 40% ethanol solution showed necrosis of only the intimal layer and partial necrosis of the medial layer and no brain swelling was observed. These findings suggest that ethanol at low concentration can be used as a relatively safe solvent for liquid embolic substances.

Animals↗
PubMed1996

Modes of Seoul virus infections: persistency in newborn rats and transiency in adult rats.

To understand the mode of persistent infection of Seoul virus in rodents, we examined the distribution of the virus genome and antibody production in infected rats. When 1-day-old rats were inoculated with the KI-83-262 strain, the S segment of viral genome was detected in sera, clots, lungs and kidneys from 3 to 184 days post inoculation (d.p.i.) by nested reverse transcriptase PCR. On the other hand, when 7-week-old rats were infected with this virus, viral genome was detected only in the lungs from 3 to 50 d.p.i. The neutralizing antibody titers of rats inoculated at 1-day of age were higher than those of rats inoculated at 7 weeks of age. In both age groups, however, the IgG avidity of antibody increased along with the course of infection. We found that urban rats (Rattus norvegicus) infected early in life harbored the virus for more than 6 months.

Animals↗
PubMed1996

Role of platelet-activating factor in pathogenesis of galactosamine-lipopolysaccharide-induced liver injury.

In an attempt to clarify the role of platelet-activating factor (PAF) in the pathogenesis of hepatic injury induced by galactosamine (GalN) plus lipopolysaccharide (LPS), effects of WEB 2086 (PAF receptor antagonist) on hepatic injury in vivo as well as on neutrophil adherence to hepatic endothelial cells in vitro have been investigated, as we have recently clarified the role of neutrophils in this experimental model of hepatic injury. Although an enhanced serum TNF-alpha level after GalN-LPS administration was not reduced by WEB 2086, hepatic injury and hepatic neutrophil accumulation in the liver after GalN-LPS administration were attenuated by WEB 2086. An in vitro study revealed that an enhanced neutrophil adhesion to hepatic endothelial cells by stimulation with the sera that were collected from the GalN-LPS-treated rats, was reduced in the presence of WEB 2086 in a dose-dependent manner. In addition, LPS, TNF-alpha, and PAF were found to enhance the neutrophil adherence to hepatic endothelial cells, which was reduced in the presence of WEB 2086. These results suggest that PAF play an important role in the GalN-LPS induced hepatic injury and that PAF receptor antagonist reduces the neutrophil adherence to hepatic endothelial cells in the liver.

Animals↗
PubMed1996

Large spleno-caval shunt not accompanied by cirrhosis or encephalopathy.

A 40-year-old man with a large spleno-caval shunt through the azygos vein is described. This was considered a rare case, because the patient had no accompanying advanced liver disease, or episodes of hepatic encephalopathy. During checks after abnormal liver function test results, a shunt vessel was detected incidentally by ultrasonography. Computed tomography, magnetic resonance imaging, and angiography demonstrated that it was a large shunt between the splenic vein and superior vena cava through the coronary and azygos veins. The patient was a hepatitis B virus carrier and was positive for anti-HBe, and had a history of heavy drinking. However, on laparoscopic examination, the liver was not cirrhotic and the biopsy revealed only mild chronic hepatitis without bridging fibrosis. There were no esophageal varices or hepatosplenomegaly. On hemodynamic evaluation, the wedge hepatic vein pressure was slightly elevated and hepatic blood flow was reduced to half the normal value. Despite the large portal-systemic shunt, the patient had no history or signs of hepatic encephalopathy. The clinical features of this rare case are discussed.

Adult↗
PubMed1996

ETA receptor-mediated role of endothelin in the kidney of DOCA-salt hypertensive rats.

Renal effects of FR139317, an endothelin ETA receptor antagonist, were examined using anesthetized normotensive and deoxycorticosterone acetate (DOCA)-salt hypertensive rats. The intravenous bolus injection of FR139317 (10 mg/kg) produced a slight decrease in mean blood pressure (MAP; -13%) in the control rats and this hypotension was accompanied by a moderate renal vasodilation (renal vascular resistance: RVR; -12%). In the DOCA-salt hypertensive rat, FR139317 had a more pronounced hypotensive effect (MAP; -26%) accompanied by a potent renal vasodilation (RVR; -33%). FR139317 significantly increased renal blood flow only in the DOCA-salt rats. In contrast, FR139317 produced a significant decrease in urine flow and urinary sodium excretion only in control rats. Northern blot analysis revealed that the renal prepro endothelin-1 (ET-1) mRNA level was significantly increased in DOCA-salt hypertensive rats. Thus, it seems likely that endogenous ET-1 is responsible for the maintenance of DOCA-salt-induced hypertension. We also suggest that at least in part, ET-1 and ETA receptors are involved in renal hemodynamic abnormalities in DOCA-salt-induced hypertension. The augmentation of renal ET-1 production may possibly have a function in the development and maintenance of DOCA-salt-induced hypertension.

Animals↗
PubMed1996

Detection of an amino acid polymorphism in hormone-sensitive lipase in Japanese subjects.

Hormone-sensitive lipase (HSL) plays an important role in energy metabolism by controlling the hydrolysis of triglycerides stored in adipose tissue. To investigate whether mutations in the HSL gene are associated with non-insulin-dependent diabetes mellitus (NIDDM), we screened for mutations of this gene using single-stranded conformation polymorphism (SSCP) in 35 Japanese subjects with NIDDM. SSCP analysis identified a variant pattern in axon 4, and the sequence showed that this variant pattern resulted from amino acid polymorphism (Arg309Cys). Subsequent study showed that this polymorphism was found in 18 of 151 NIDDM patients and 10 of 97 nondiabetic subjects, but allele frequency was not significantly different between the two groups (P = .7). Body mass index, serum triglyceride, and high-density lipoprotein (HDL) cholesterol were not different in subjects with and without the polymorphism. But serum total cholesterol was higher in subjects with the polymorphism than in subjects without it (P = .0005). These data indicate that this HSL polymorphism is not associated with NIDDM, obesity, and serum triglyceride level. However, an effect of the polymorphism to elevate serum total cholesterol has not been excluded, although further study is necessary to resolve its association with cholesterol metabolism.

Alleles↗
PubMed1996

Hypoglossal premotor neurons in the rostral medullary parvocellular reticular formation participate in cortically-induced rhythmical tongue movements.

Premotor neurons projecting to the hypoglossal (XII) nucleus and participating in cortically-induced rhythmical tongue movements were defined by extracellular recording in the cat. Two thirds (37/57) of antidromically identified XII premotor neurons sampled in the rostral medullary parvocellular reticular formation showed changes in their firing pattern during cortically-induced rhythmical activity of XII motoneurons. Fifteen of the 37 neurons showed a firing in phase with rhythmical activity of either the medial or lateral branch of the XII nerve (phasic-type). The remaining 22 neurons showed an increase in discharge with no apparent correlation with cortically-induced rhythmical activity of the XII nerve (non-phasic-type). Among the phasic- and non-phasic-type neurons, 30 neurons received inputs from the cortical masticatory area, and 14 neurons received further excitatory inputs from the inferior alveolar nerve. By systematic mapping of the stimulation sites effective for antidromic activation, four phasic-type neurons were confirmed to project to either tongue-protruding or -retracting XII motoneuron pools in accordance with their burst firing, suggesting that the phasic-type premotor neurons contribute to excitation of XII motoneurons during cortically-induced rhythmical activity. It is concluded that there are the XII premotor neurons driving cortically-induced rhythmical activity of XII motoneurons in the rostral medullary parvocellular reticular formation.

Animals↗
PubMed1996

[1-11C]octanoate as a potential PET tracer for studying glial functions: PET evaluation in rats and cats.

To evaluate the ability of [1-11C]octanoate as a PET tracer for imaging the brain, we examined its distribution in the brain and surrounding tissues in rats and cats with PET. In rats, owing to the accumulated radioactivity in the harderian glands, clear brain images were not obtained at rostral levels. In cats, the brain was imaged clearly at every level of the coronal brain slices, suggesting the potential of [1-11C]octanoate for imaging the brain.

Animals↗