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Biomedical subjects

Y Inaba

Publications and source records attributed to Y Inaba.

At least 19 recordsLinked to original sources
PubMed2007

Reduced GABAB receptor subunit expression and paired-pulse depression in a genetic model of absence seizures.

Neocortical networks play a major role in the genesis of generalized spike-and-wave (SW) discharges associated with absence seizures in humans and in animal models, including genetically predisposed WAG/Rij rats. Here, we tested the hypothesis that alterations in GABA(B) receptors contribute to neocortical hyperexcitability in these animals. By using Real-Time PCR we found that mRNA levels for most GABA(B(1)) subunits are diminished in epileptic WAG/Rij neocortex as compared with age-matched non-epileptic controls (NEC), whereas GABA(B(2)) mRNA is unchanged. Next, we investigated the cellular distribution of GABA(B(1)) and GABA(B(2)) subunits by confocal microscopy and discovered that GABA(B(1)) subunits fail to localize in the distal dendrites of WAG/Rij neocortical pyramidal cells. Intracellular recordings from neocortical cells in an in vitro slice preparation demonstrated reduced paired-pulse depression of pharmacologically isolated excitatory and inhibitory responses in epileptic WAG/Rij rats as compared with NECs; moreover, paired-pulse depression in NEC slices was diminished by a GABA(B) receptor antagonist to a greater extent than in WAG/Rij rats further suggesting GABA(B) receptor dysfunction. In conclusion, our data identify changes in GABA(B) receptor subunit expression and distribution along with decreased paired-pulse depression in epileptic WAG/Rij rat neocortex. We propose that these alterations may contribute to neocortical hyperexcitability and thus to SW generation in absence epilepsy.

Animals↗
PubMed2006

Parental longevity and mortality amongst Japanese men and women: the JACC Study.

OBJECTIVES: To examine whether the risk of mortality varies according to parents' age at death. DESIGN AND SUBJECTS: A large prospective study in Japanese men and women from 45 communities across Japan. A total of 51 485 men and women aged 40-79 years completed self-administered questionnaires at baseline and followed up for 9.6 years. RESULTS: The risk of mortality from stroke, cardiovascular disease, and all causes was 20-30% lower in men and women with fathers who died at age > or = 80 years, compared with those with fathers whose age at death was <60 years. A similar reduction was found when the age at death of mothers was > or = 85 years compared with <65 years. Furthermore, the risk reduction was more evident amongst persons with both parents being long-lived parents compared with those with being short-lived parents, especially for death from cardiovascular disease. CONCLUSIONS: Our findings indicate that parental longevity could be a predictor for reduced risk of mortality from stroke, cardiovascular disease, and all causes for both Japanese men and women.

Adult↗
PubMed2006

Synaptic hyperexcitability of deep layer neocortical cells in a genetic model of absence seizures.

We used sharp-electrode, intracellular recordings in an in vitro brain slice preparation to study the excitability of neocortical neurons located in the deep layers (>900 microm from the pia) of epileptic (180-210-days old) Wistar Albino Glaxo/Rijswijk (WAG/Rij) and age-matched, non-epileptic control (NEC) rats. Wistar Albino Glaxo/Rijswijk rats represent a genetic model of absence seizures associated with generalized spike and wave (SW) discharges in vivo. When filled with neurobiotin, these neurons had a typical pyramidal shape with extensive apical and basal dendritic trees; moreover, WAG/Rij and NEC cells had similar fundamental electrophysiological and repetitive firing properties. Sequences of excitatory postsynaptic potentials (EPSPs) and hyperpolarizing inhibitory postsynaptic potentials (IPSPs) were induced in both the strains by electrical stimuli delivered to the underlying white matter or within the neocortex; however, in 24 of 55 regularly firing WAG/Rij cells but only in 2 of 25 NEC neurons, we identified a late EPSP that (1) led to action potential discharge and (2) was abolished by the N-methyl-D-aspartate (NMDA) receptor antagonist 3,3-(2-carboxypiperazine-4-yl)-propyl-1-phosphonate (20 microM; n = 8/8 WAG/Rij cells). Finally, we found that the fast and slow components of the stimulus-induced IPSPs recorded during the application of glutamatergic receptor antagonists had similar reversal potentials in the two strains, while the peak conductance of the fast IPSP was significantly reduced in WAG/Rij cells. These findings document an increase in synaptic excitability that is mediated by NMDA receptors, in epileptic WAG/Rij rat neurons located in neocortical deep layers. We propose that this mechanism may be instrumental for initiating and maintaining generalized SW discharges in vivo.

Animals↗
PubMed2006

Dietary fat and meat intake and idiopathic pulmonary fibrosis: a case-control study in Japan.

SETTING: There is sparse epidemiologic information regarding the role of dietary factors in the development of idiopathic pulmonary fibrosis (IPF). OBJECTIVE: To examine the relationship between specific types of fatty acids and selected foods high in fat and IPF in Japan. DESIGN: Included were 104 cases aged > or = 40 years who had been diagnosed in the last 2 years in accordance with the most recent criteria. Controls aged > or = 40 years consisted of 56 hospitalised patients diagnosed as having acute bacterial pneumonia and four out-patients with common cold. RESULTS: Intake of saturated fatty acids, mono-unsaturated fatty acids, n-6 polyunsaturated fatty acids and meat was independently associated with an increased risk of IPF. Specifically, the multivariate OR for comparison of the highest with the lowest quartile of intake of saturated fatty acids was 6.26 (95%CI 1.79-24.96, P for trend = 0.01) and for meat it was 7.19 (95%CI 2.15-27.07, P for trend = 0.02). Intake of cholesterol, n-3 polyunsaturated fatty acids, fish, eggs and dairy products was not related to the risk. CONCLUSION: These findings suggest that consumption of saturated fatty acids and meat may increase the risk of IPF.

Adult↗
PubMed2005

Periodic oscillatory activity in parahippocampal slices maintained in vitro.

Brain slices maintained in vitro have been extensively used for studying neuronal synchronization. However, the validity of this approach may be questioned since pharmacological procedures are usually required to elicit spontaneous events similar to the EEG activity recorded in vivo. Here, we report that when superfused with control medium, rat brain slices comprising the entorhinal and perirhinal cortices along with a portion of the basolateral/lateral nuclei of the amygdala can synchronously generate periodic oscillatory activity at 5-11 Hz every 5-30 s. The periodic events: (i) correspond intracellularly to synaptic depolarizations in regularly firing neurons analyzed in the three areas; (ii) have no fixed site of onset; (iii) spread with time lags of 8-20 ms; and (iv) continue to occur asynchronously after their surgical isolation. NMDA receptor antagonism reduced the duration of the oscillatory events, while glutamatergic non-NMDA receptor antagonism abolished them. Activation of mu-opioid receptors, a procedure that hyperpolarizes interneurons thus decreasing GABA release, reversibly decreased the rate of occurrence of periodic oscillatory activity (POA). However, periodic events continued to occur during application of GABA(A) or GABA(B) receptor antagonists as well as in the presence of the cholinergic agent carbachol. We also found that POA was abolished by baclofen and irreversibly reduced by the gap junction decoupler carbenoxolone. These findings demonstrate that parahippocampal networks in a brain slice preparation can generate periodic, synchronous activity under quasi-physiological conditions. These network oscillations (i) reflect the activation of ionotropic glutamatergic and GABAergic receptors, (ii) are contributed by gap-junction interactions, and (iii) are controlled by GABA(B) receptors that are presumably located presynaptically.

Action Potentials↗
PubMed2004

Cervical oesophageal stent placement via a retrograde transgastric route.

During attempted oesophageal stent placement in a patient with cervical oesophageal cancer in whom swallowing of even saliva was impossible, transoral access to the cervical oesophagus was unsuccessful. Under ultrasound and fluoroscopy guidance, percutaneous gastric puncture was performed, and using an angiographic catheter and guidewire, access to the oesophagus by a retrograde transgastric route was successfully achieved. The obstructed segment of the oesophagus was traversed. It was then possible to pull the guidewire through the mouth and place an oesophageal stent via an antegrade approach.

Esophageal Neoplasms↗
PubMed2002

Inhibitory effects of organotin compounds on voltage-dependent, tetrodotoxin-resistant Na+ channel current in guinea pig dorsal root ganglion cells.

The effects of organotin compounds on voltage-dependent, tetrodotoxin (TTX)-resistant Na+ channel current (I(Na)) in single cells isolated from guinea pig dorsal root ganglion were investigated using a whole cell patch clamp technique. Extracellular application of tributyltin (TBT) inhibited I(Na) in a concentration-dependent manner with an IC50 of 7.2 microM. TBT (100 microM), when applied intracellularly, was without effect. Triphenyltin (TPT, 100 microM) and dibutyltin (DBT, 100 microM), applied extracellularly, inhibited I(Na) with an efficacy ranking of TBT>TPT>DBT. Monobutyltin (100 microM), whether applied externally or internally, had little effect on I(Na). TBT (30 microM) significantly prolonged both time to peak and half-decay time of I(Na) and shifted the activation curve of I(Na) in the positive direction without changing the slope. No such effect was produced by TPT (100 microM). The results indicate that organotin compounds inhibit voltage-dependent, TTX-resistant Na+ channel activity and suggest that the inhibitory action may account, at least in part, for their neurotoxic effects.

Animals↗
PubMed2002

Epidemiology of idiopathic cardiomyopathy in Japan: results from a nationwide survey.

OBJECTIVE: To estimate the total number of patients with idiopathic cardiomyopathy in Japan and the prevalence of the disorder. DESIGN: A nationwide epidemiological survey. SETTING: Hospitals selected randomly from among all hospitals in Japan. PATIENTS: Patients presenting with any of the three types of idiopathic cardiomyopathy: dilated cardiomyopathy, hypertrophic cardiomyopathy, and restrictive cardiomyopathy. MAIN OUTCOME MEASURES: The total number of patients in Japan was estimated using the sampling and response rates in each stratum with respect to hospital size. The second survey was conducted for patients reported in the first survey in order to obtain detailed information, including age, sex, and specific clinical data. RESULTS: Estimated patient totals and 95% confidence intervals (CI) were 17 700 (95% CI 16 500 to 18 800) for dilated cardiomyopathy, 21 900 (95% CI 20 600 to 23 200) for hypertrophic cardiomyopathy, and 300 (95% CI 250 to 350) for restrictive cardiomyopathy. Crude prevalence per 100 000 population was estimated as 14.0 for dilated cardiomyopathy, 17.3 for hypertrophic cardiomyopathy, and 0.2 for restrictive cardiomyopathy; crude incidence per 100 000 person-years was estimated as 3.58, 4.14, and 0.06, respectively. CONCLUSIONS: The total number and prevalence of patients with idiopathic cardiomyopathy in Japan are estimated for the first time in a nationwide survey. The prevalence of dilated cardiomyopathy in Japan appears to be about half that of Western populations, while that of hypertrophic cardiomyopathy is about the same.

Adolescent↗
PubMed2002

Mediastinal abscess successfully treated by percutaneous drainage using a unified CT and fluoroscopy system.

We report two patients with mediastinal abscess developing after surgery for oesophageal cancer who were treated by percutaneous drainage using a unified CT and angiography system, which allows both CT and fluoroscopy to be conducted with the patient on the same bed. Fine needle puncture is performed under CT guidance and this needle is used as a tandem for insertion of the drainage needle under fluoroscopic guidance, making safe puncture possible whilst confirming the position of the needle tip. Moreover, contrast medium can be injected from the drainage tube, allowing the extent of the abscess cavity to be determined by fluoroscopy and CT, thereby making accurate drainage possible.

Abscess↗
PubMed2002

Severe obstruction of the superior vena cava caused by tumor invasion. Recanalization using a PTFE-covered Z stent.

Bare stents are commonly used for the treatment of malignant vena cava stenoses. However, the therapeutic effect of treatment using bare stents for cases with intraluminal tumor invasion is not satisfactory. We report a case with severe obstruction of the superior vena cava caused by tumor invasion of mediastinal lymph node metastases from colon cancer, which was successfully treated by the recanalization of superior vena cava using a polytetrafluoroethylene-covered Z stent. The covered stent could not be fully expanded at first, and re-obstruction developed at the stented site due to thrombus formation soon after stenting. So, the additional balloon dilatation made the stent expend fully on another day of stenting. After the balloon dilatation blood flow improved immediately and the clinical symptoms associated with the superior vena cava obstruction resolved. Thereafter no symptomatic recurrence has been observed in 12 months of follow-up period.

Angioplasty, Balloon↗
PubMed2001

Daphnicyclidins A-H, novel hexa- or pentacyclic alkaloids from two species of Daphniphyllum.

Eight highly modified Daphniphyllum alkaloids with unprecedented fused hexa- or pentacyclic skeletons, daphnicyclidins A-H (1-8), have been isolated from the stems of Daphniphyllum humile and D.teijsmanni, and their structures were elucidated on the basis of spectroscopic data and chemical means. The stereochemistry was elucidated by combination of NOESY correlations, X-ray crystallographic data, and CD analyses.

Alkaloids↗
PubMed2001

Plasma thrombin-antithrombin III complex is associated with the severity of experimental autoimmune encephalomyelitis.

Previous studies have shown that activation of blood coagulation and fibrin depositions around CNS vessels are observed in animals with experimental autoimmune encephalomyelitis (EAE), which provides an animal model for human autoimmune demyelinating disorders. We examined the values of peripheral blood fibrinogen, thrombin-antithrombin III complex (TAT), fibrinolytic activity, and fibrin degradation products in Lewis rats with EAE to elucidate the role of the blood coagulation-fibrinolysis system in EAE. Plasma TAT values increased immediately prior to development of symptoms, and decreased according to the improvement of symptoms. There was significant correlation between TAT values and clinical scores of EAE; other markers were not correlated with the symptoms of EAE. These results suggest that plasma TAT levels are sensitive markers of the severity of EAE, and may be useful clinical indicators for the severity of human autoimmune demyelinating disorders.

Animals↗
PubMed2001

Right gastric artery embolization to prevent acute gastric mucosal lesions in patients undergoing repeat hepatic arterial infusion chemotherapy.

PURPOSE: The purpose of the study was to investigate the technical outcome and clinical effect of right gastric artery (RGA) embolization to prevent acute gastric mucosal lesions caused by influx of anticancer agents into the RGA in patients undergoing repeat hepatic arterial infusion chemotherapy (HAIC). MATERIALS AND METHODS: In 217 patients with malignant hepatic tumors, we attempted RGA embolization with use of metallic coils and/or a mixture of n-butyl cyanoacrylate (n-BCA) and iodized oil, along with the embolization of the gastroduodenal artery. After this procedure, an infusion catheter was placed radiologically and HAIC was performed. We then evaluated the technical outcome and clinical effect of RGA embolization. RESULTS: RGA embolization was technically successful in 201 of 217 patients (93%). Major complications--nausea, epigastric pain, and fever--were noted in 12%, 4%, and 2% of successful cases, respectively, and were treated conservatively. Recanalization occurred in 4% (nine of 201) of the patients. Eventually, sufficient RGA embolization was achieved in 192 patients. The incidence of acute gastric mucosal lesions confirmed endoscopically was only 3% (five of 192) in patients with sufficient RGA embolization, whereas it was 36% (nine of 25) in patients without sufficient RGA embolization, with a significant difference (P <.01). CONCLUSION: RGA embolization is a highly feasible procedure that can reduce the incidence of acute gastric mucosal lesions associated with HAIC.

Acute Disease↗
PubMed2001

Biopsy of lung nodules with use of I-I device under intermittent CT fluoroscopic guidance: preliminary clinical study.

PURPOSE: To investigate the efficacy of computed tomography (CT) fluoroscopy and a new needle holder (the I-I device) in lung nodule biopsy. MATERIALS AND METHODS: The I-I device is made of acrylate resin and was used to keep the entire needle in the tomographic plane. This study consisted of biopsies of 79 lung nodules in 77 patients. The final diagnoses were malignant in 54 patients, benign in 23, and unconfirmed in two. The biopsy procedure time from the beginning of the CT fluoroscopy procedure to the removal of the needle was measured for 24 needle passes. The radiation dose on the physician's hand was measured in five cases with use of a thermoluminescence ring. RESULTS: Fifty-one malignant and 20 benign lesions were correctly diagnosed with histologic specimens (90%). In 58 of 77 patients (75%), the biopsy procedures were completed within a single breath-hold. Pneumothorax occurred in 20 of 77 patients (26%) and chest tube insertion was required in five. The incidence of pneumothorax was significantly lower in patients who held their breath during biopsy procedures compared with those who did not (P < .0001; chi2 test). The biopsy procedure time ranged from 15 to 39 seconds (mean: 28.2 sec). The mean radiation dose on the physician's hand was 2 mSv/case. CONCLUSION: The diagnostic accuracy of biopsy with use of the I-I device under CT fluoroscopic guidance is comparable with that of the conventional method; however, a combination of CT fluoroscopy and the I-I device enables rapid biopsy procedures.

Biopsy, Needle↗
PubMed2001

Antioxidant mechanism of carnosic acid: structural identification of two oxidation products.

To determine the antioxidant mechanism of food phenolics against the oxidation of food components, the reaction of carnosic acid, an antioxidative constituent of the popular herbs sage and rosemary, was investigated in the presence of ethyl linoleate and the radical oxidation initiator 2,2'-azobis(2,4-dimethylvaleronitrile). During this process, carnosic acid was oxidized to an o-quinone and a hydroxy p-quinone, the chemical structures of which were confirmed by physical and chemical techniques. From a quantitative time course analysis of the production of these quinones, an antioxidant mechanism of carnosic acid is proposed, consisting of the oxidative coupling reaction with the peroxyl radical at the 12- or 14-position of carnosic acid and subsequent degradation reactions.

Abietanes↗
PubMed2001

Adenocarcinoma arising from the prostatic duct mimicking transitional cell carcinoma.

A 71-year-old man was first diagnosed with primary transitional cell carcinoma of the prostate with a skip lesion on the distal urethra. The patient received three courses of intra-arterial chemotherapy of cisplatin (CDDP) and pirarubicin (THP-ADM) followed by a radical prostatectomy. Histopathologic examination of the prostatectomy specimen revealed adenocarcinoma invasion along the prostatic duct extending to the peripheral acini, which was diagnosed as ductal adenocarcinoma. The clinical and histopathologic features of this case are entirely different from usual adenocarcinomas of the prostate. This rare histopathologic feature should be recognized as 'ductal carcinoma of the prostate', to distinguish it from papillary adenocarcinoma or adenocarcinoma with endometrioid features. The patient has had no sign of recurrence 14 months after the operation. CDDP-based chemotherapy followed by radical prostatectomy may be one of the promising therapeutic modalities for this rare entity.

Adenocarcinoma↗
PubMed2001

Pre-operative detection of malignant hepatic tumours: value of combined helical CT during arterial portography and biphasic CT during hepatic arteriography.

AIMS: The purpose of our study was to evaluate the observer performance with combined helical CT during arterial portography (CTAP) and biphasic CT hepatic arteriography (CTHA) in the pre-operative detection of malignant hepatic tumours. METHODS: Computed tomography images obtained in 41 patients with suspected hepatic tumours were retrospectively reviewed. In a blind fashion, three off-site, independent radiologists reviewed CTAP and early-phase CTHA combined for the first review, then late-phase CTHA was added for the second review. Statistical analysis was conducted on lesion-by-lesion and segment-by-segment bases; a total of 328 liver segments including 65 segments with 74 malignant hepatic tumours ranging in size from 5 to 100 mm (mean, 21.4 mm) were analysed. RESULTS: Sensitivity for detection of liver segments harbouring tumours of CTAP and biphasic CTHA combined (82%) was identical to that of CTAP and early-phase CTHA combined (82%). Specificity of CTAP and biphasic CTHA combined (93%) was greater than that of CTAP and early-phase CTHA combined (90%, P < 0.005). The mean confidence level for the 74 tumours significantly increased by adding late-phase CTHA (P < 0.0005). The mean confidence level for 100-142 benign perfusion abnormalities detected with CTAP and early-phase CTHA combined significantly decreased by adding late-phase CTHA (P < 0.0005). CONCLUSION: By combining late-phase CTHA with CTAP and early-phase CTHA information, the specificity for the detection of malignant hepatic tumours rises significantly, allowing more accurate preoperative tumour detection.

Aged↗