PubMed Health⌕ Search

Biomedical subjects

Y Yokoi

Publications and source records attributed to Y Yokoi.

At least 37 records · Page 2Linked to original sources
PubMed1998

[Clinical results of endovascular stent graft repair for fifty cases of thoracic aortic aneurysms].

Between February 1995 and December 1997, 50 cases (55 lesions) of thoracic aortic aneurysms including 20 cases of aortic dissections were treated with an endovascular technique using the stent grafts. All patients were treated in the operating room under general anesthesia and the stent grafts were implanted through 18 Fr. or 20 Fr. sheaths via femoral arteries under fluoroscopic guidance. The stent graft was composed of several units of self-expanding stainless-steel Z stents covered with an ultra-thin polyester fabric. Stent graft deployment was technically successful in 53 of 55 lesions (delivery success rate: 96.4%). Exclusion of the aneurysms and entry closing without endoleak were achieved within two weeks after the operation in 43 of 53 lesions (initial success rate: 81.1%). Endoleak was found in 10 lesions (minor endoleak: 8 and major endoleak: 2 lesions). Two patients died in the periopertive period of delivery failures as injury to external iliac artery and damage to the delivery sheath caused by tortuous and narrow access routes. Endovascular stent graft repair of thoracic aortic aneurysms is minimally invasive operation in comparison with conventional surgical graft replacement with extracorporeal circulation. These early results suggest that the stent graft repair is possibly safe and useful treatment for the patients of thoracic aortic aneurysms especially in high risk patients. However, careful long-term follow-up is necessary to prove the value and the effects of this endovascular treatment and improvement of the stent graft system and technical training of endovascular surgery for operators are required to reduce the delivery failure and to determine the stent graft repair is reliable treatment.

Adult↗
PubMed1998

Oesophageal hiatal hernia-induced hydropneumothorax.

The patient presented with acute and constant abdominal pain. He had had a lobectomy of the left lung three months before. On the 4th day in hospital the pain increased and he went into temporary shock. The next day a hydropneumothorax and incarcerated stomach were revealed by chest X-ray and computed tomography. He was transferred to the University Hospital immediately and underwent an operation. The diagnosis was an incarcerated para-oesophageal hernia with hydropneumothorax and perforation of the stomach. As a para-oesophageal hernia may be fatal, it is important to diagnose and treat it early.

Abdominal Pain↗
PubMed1998

Hepatic stellate cell contraction is inhibited by lipo-prostaglandin E1 in vitro.

Prostaglandin E1 (PGE1) has been reported to have, experimentally and clinically, a protective effect against liver damage. This effect may result from the relaxation of hepatic stellate cells, whose contraction induces vasoconstriction of hepatic sinusoids. However, prostaglandins are unstable and a new drug delivery system is necessary to administer a sufficient amount of prostaglandin to achieve a protective effect in the liver. The aim of the study is to investigate the effects of lipo-prostaglandin E1 (lipo-PGE1) which has a novel drug delivery system on the stellate cell contraction induced by endothelin-1 in vitro. Lipo-PGE1 inhibited endothelin-1-induced stellate cell contraction in concentrations of 10, 30 and 50 ng/mL. Therefore, lipo-PGE1 may show a cytoprotective effect in the liver through the relaxation of stellate cells and an increase in the hepatic sinusoidal blood flow.

Alprostadil↗
PubMed1997

Effects of gamma-butyric acid on the release of thyrotropin-releasing hormone from the rat retina in vitro.

Effects of gamma-butyric acid (GABA) on the release of thyrotropin-releasing hormone (TRH) from the rat retina in vitro were studied. The rat retina was incubated in medium 199 (pH 7.4) with 1.0 mg/ml of bacitracin and 100 micrograms/ml of ascorbic acid (medium). The amount of TRH release into the medium was measured by radioimmunoassay. The TRH release from the rat retina was inhibited significantly in a dose-related manner with the addition of GABA, but not with bicuculline. The inhibitory effect of GABA on TRH release from the retina was blocked by adding bicuculline to the medium. The findings suggest that the GABAergic system inhibits TRH release from the rat retina in vitro.

Animals↗
PubMed1997

[Diagnosis of neonatal enterovirus meningitis by reverse transcription-polymerase chain reaction].

We evaluated the potential clinical utility of a reverse transcription-polymerase chain reaction (RT-PCR) for neonatal enterovirus meningitis, comparing the results with viral culture and white blood cell (WBC) counts in the cerebrospinal fluid (CSF). Of the 41 cases of enteroviral infection, 31 cases (76%) were finally diagnosed as meningitis by either viral culture, CSF WBC count or RT-PCR. Of those with culture positive and negative, the RT-PCR positive rates were 10 (100%) and 6/13 (46%), respectively. Of those with and without WBC increase in the CSF, the RT-PCR positive rates were 18/20 (90%) and 5/14 (36%), respectively. There was one RT-PCR positive case (1/6, 17%) among those with culture negative and no WBC increase in the CSF. RT-PCR performed on CSF is a sensitive and specific method for the diagnosis of neonatal enterovirus meningitis.

Enterovirus Infections↗
PubMed1997

Organ distribution of iodide transporter (symporter) in the rat: immunohistochemical study.

Iodide transporter/symporter (NIS) was identified immunohistochemically in rat tissues using specific antipeptide serum. Anti-NIS serum was raised in New Zealand white rabbits immunized with a conjugate of synthetic NIS peptide (39-53) with bovine serum albumin. Immunohistochemical analysis was performed by avidine-biotin complex method. NIS immunoreactivity was visualized in the thyroid gland, gastric and small intestine mucosa, anterior pituitary, adrenal medulla, pancreatic islets, kidney, chorioid plexus and several brain and spinal cord nuclei. When using antiserum preincubated with synthetic NIS peptide (39-53) or rat thyroid homogenate containing NIS, no significant stain of the thyroid gland was detected. These findings suggest that NIS is widely distributed and that the method used is suitable for studying the distribution of NIS in rats.

Journal Article↗
PubMed1996

Effects of serotonin on the release of thyrotropin-releasing hormone from the rat retina in vitro.

Effects of serotonin on the release of thyrotropin-releasing hormone (TRH) from the rat retina were studied in vitro. The retina was incubated in medium 199 (pH 7.4) with 1.0 mg/ml of bacitracin and 100 micrograms/ml of ascorbic acid (medium) for 20 min. The amount of TRH release into the medium was measured by radioimmunoassay. The TRH release from the rat retina was inhibited significantly in a dose-related manner with the addition of serotonin and enhanced with cyproheptadine. The inhibitory effect of serotonin on TRH release from the retina was blocked with the addition of cyproheptadine. The elution profile of methanol extract of the rat retina was identical to that of synthetic TRH. The findings suggest that the serotonergic system inhibits TRH release from the rat retina in vitro.

Animals↗
PubMed1996

(+)-cis-3,5-dimethyl-2-(3-pyridyl) thiazolidin-4-one hydrochloride (SM-12502) as a novel substrate for cytochrome P450 2A6 in human liver microsomes.

(+)-cis-3,5-dimethyl-2-(3-pyridyl)thiazolidin-4-one hydrochloride (SM-12502) was oxidized by human liver microsomes to produce the S-oxide as a sole metabolite. Indirect evidence suggested that the S-oxidation was catalyzed by cytochrome P450 (CYP). Eadie-Hofstee plots showed biphasic pattern, suggesting that at least two enzymes were involved in the S-oxidation in human liver microsomes. Kinetic parameters of the S-oxidase with high-affinity showed Km and Vmax values of 20.9 +/- 4.4 microM and 0.111 +/- 0.051 nmol/min/mg microsomal protein, respectively. The S-oxidase activity was inhibited by coumarin and anti-CYP2A antibody. Among the contents of forms of CYP 20 samples of human liver microsomes, the content of CYP2A6 correlated with S-oxidase activity measured with 50 microM SM-12502 (r = .808, P < .0005). A close correlation (r = .908, P < .0001) was observed between activities of SM-12502 S-oxidase and coumarin 7-hydroxylase. Microsomes from genetically engineered human B-lymphoblastoid cells expressing CYP2A6 metabolized SM-12502 to the S-oxide efficiently. The results indicate that CYP2A6 isozyme is a major form of CYP responsible for the S-oxidation of SM-12502 in human liver microsomes. Thus, SM-12502 will be a useful tool in further research to analyze a human genetic polymorphism of CYP2A6.

Animals↗
PubMed1996

[Atherectomy in patients with arteriosclerosis obliterans: angiographic follow-up study of 186 lesions in 146 patients].

Atherectomy (ATE) is a new catheter-mediated technique for the removal of atheroma in patients with arteriosclerosis obliterans (ASO). ATE was performed using 7-10 Fr. Simpson Peripheral Athero Track catheters at 186 sites in 146 patients, whose lesions involved 49 common iliac arteries, 66 external iliac arteries, 68 femoral arteries and three other arteries. The initial success rate was 94.1%. The mean percent of the diameter stenosis was reduced from 79.0 +/- 1.2% (mean +/- SD) to 22.7 +/- 1.0%. There were two cases of perforation that required surgical treatment (1.1%). The complication rate was 4.4%. The 0.5-, 1-, 2- and 3-year patency rates were 87.6%, 79.6%, 62.5% and 62.5%, respectively. The rate of long-term patency in each segment of arterial lesions revealed that the patency rate in the common iliac artery was significantly higher than the rates in the external iliac artery (p < 0.05) and femoral artery (p < 0.01). The patency rates for long lesions (> or = 2.0 cm) and occluded lesions were significantly (p < 0.01) lower than those for short lesions (< 2.0 cm). Diabetic patients had a higher re-stenosis rate than nondiabetic patients (p < 0.05). In conclusion, ATE is an effective new method for the treatment of patients with ASO.

Aged↗
PubMed1996

[Clinical features of anterior inferior cerebellar artery territory infarcts--a study of ten patients].

Clinical features of the anterior inferior cerebellar artery (AICA) territory infarcts were investigated in ten patients, ranging in age from 38 to 76 years. In all patients, there were MR images of infarction located in the area supplied by the AICA. The lesion was on the left side in 6 patients and right side in 4. The lesion of brain stem including the middle cerebellar peduncle was found in 7 patients and that extended to the cerebellum was in 3 patients. The main ipsilateral neurological signs were the VII and VIII cranial nerves palsy and cerebellar ataxia. The V and VI cranial nerves palsy. Horner's syndrome, and dysphagia were also present. The main contralateral sign was superficial sensory disturbance, but no hemiplegia. The underlying pathology included chiefly hyperlipidemia, hypertension, and diabetes mellitus. Cerebral angiography was performed in 8 patients, most of which was observed severe arteriosclerosis suggesting poor hemodynamics in the vertebral and basilar arteries. The prognosis was relatively good, but the VII, VIII, and V cranial nerves palsy and contralateral superficial sensory disturbance remained as the sequelae. As mentioned above, there were various neurological findings and MR images in AICA territory infarcts. Especially there were some patients whose lesion extended to the upper medulla and neurological findings were similar to the Wallenberg syndrome. It is important that one investigates not only axial slices but also coronal slices of MR image to estimate the extension of AICA territory infarct.

Adult↗
PubMed1995

Hepatic release of endothelin-1 after warm ischemia. Reperfusion injury and its hemodynamic effect.

This study investigated the release of endothelin (ET)-1 from the liver after warm ischemia/reperfusion (I/R) injury. Wistar rats were subjected to 120 min of warm hepatic ischemia by clamping the hepatic hilum under porto-jugular shunting. Reperfusion was performed by unclamping. The rats were divided into 2 groups receiving intravenous treatment with an anti-ET-1 mAb before ischemia (AET group) and with mouse immunoglobulin G (sham group). Hepatic blood flow was assessed by laser-Doppler flowmetry and reflectance spectrophotometry and was compared between the 2 groups along with the bile flow rate. The ET-1 concentrations of hepatic venous and portal blood were determined in the sham group, and the portal blood endotoxin levels were assayed in both groups. Both groups developed transient hypotension after reperfusion, but hepatic blood flow subsequently showed a significant improvement in the AET group. Hepatic congestion was detected in the sham group by both reflectance spectrophotometry and histological examination. After reperfusion, bile flow was significantly greater in the AET group. The portal endotoxin concentration showed no increase in both groups, and the hepatic venous blood ET-1 level in the sham group was significantly higher until 3 hr after reperfusion compared to the portal blood level. The 30-day survival rate was 50% in the AET group, whereas all the sham rats died within 12 hr. ET-1 was released from the liver after I/R injury and apparently participated in systemic and local hemodynamic changes that affected survival.

Animals↗
PubMed1995

High levels of serum lipoprotein(a) in patients with ischemic heart disease with normal coronary angiogram and thromboangiitis obliterans.

To determine whether lipoprotein(a) (Lp(a)) contributes to the acceleration of cardiovascular diseases without atherosclerotic lesion, we have measured serum Lp(a) level in male subjects aged 40-69 years with thromboangiitis obliterans (n = 40) and ischemic heart disease (IHD) with normal coronary angiogram (n = 35) in addition to subjects with arteriosclerosis obliterans (n = 123) and IHD with atherosclerotic coronary lesion (n = 203). Cases who had no IHD, arteriosclerosis obliterans or thromboangiitis obliterans were selected as a control group (n = 316). Subjects without any diseases or abnormal findings in physical examination and laboratory data were selected from the control group as the healthy control group (n = 156). The Lp(a) levels of arteriosclerosis obliterans and IHD with atherosclerotic coronary lesion were significantly higher (17.0 mg/dl and 13.1 mg/dl; median) than those of control and healthy control groups (9.9 mg/dl and 9.4 mg/dl, respectively) (P < 0.01), in agreement with previous reports. Furthermore, the Lp(a) level of IHD with normal coronary angiogram group was significantly higher (18.9 mg/dl) than those of the control and healthy control groups (P < 0.05). The Lp(a) level of thromboangiitis obliterans group was also much higher (21.3 mg/dl) than that of the healthy control group (P < 0.05). The current study suggests that Lp(a) is one of the independent risk factors for the development of atherosclerotic diseases such as arteriosclerosis obliterans and IHD with atherosclerotic coronary lesion.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗