Biomedical subjects

H Osanai

Publications and source records attributed to H Osanai.

At least 19 recordsLinked to original sources

PubMed2001

Preoperative computed tomography diagnosis of non-recurrent inferior laryngeal nerve.

OBJECTIVE: The non-recurrent inferior laryngeal nerve (NRILN) is a nerve anomaly that is associated with the developmentally aberrant subclavian artery. Thus, it is possible to predict NRILN by preoperative diagnosis of an aberrant subclavian artery. Preoperative recognition of the NRILN should be advantageous in the prevention of intraoperative nerve damage. The purpose of this study was to assess the possibility of diagnosis of an aberrant subclavian artery by computed tomography (CT) of the neck, which is often performed before thyroid surgery. METHODS: We retrospectively studied the preoperative CT films from 594 thyroid or esophageal surgery patients treated in our hospital between May 1995 and December 2000. An NRILN was identified intraoperatively in 6 of these patients, and a right recurrent inferior laryngeal nerve (RILN) was observed in 588 of these patients. We evaluated whether the brachiocephalic artery could be identified on the CT scan and classified the positional relationship between the right subclavian artery and the tracheoesophagus into three types. RESULTS: The brachiocephalic artery was identified on the CT films in 158 cases, all of which were cases of RILN. The right subclavian artery was detected on the ventral side of the membranous wall of the trachea in all 588 RILN cases, whereas it was detected on the dorsal side in all 6 NRILN cases. CONCLUSIONS: It was possible to predict an aberrant subclavian artery by identifying the brachiocephalic artery and position of the right subclavian artery on the CT film of the neck. When an anomaly of the subclavian artery is thus preoperatively detected, NRILN can be preoperatively predicted, which likely will enable prevention of vocal cord paralysis.

Aged↗

PubMed2001

The apolipoprotein E genotype influences the risk for vasospastic angina.

It has been suggested that people with the epsilon4 allele of the apolipoprotein E (apoE) polymorphism and the deletion (D) allele of the insertion (I/D) polymorphism of angiotensin-converting enzymes, are at a greater risk for coronary artery disease. However, only a few studies have examined the relationships between vasospastic angina (VSA) and genotype, especially with the apoE polymorphism. In the present study, 76 patients with VSA without significant fixed coronary artery stenosis, 149 patients with ischemic heart disease (IHD) who had 75% or more luminal diameter narrowing and 213 healthy subjects were enrolled. The odds ratio for VSA of the epsilon4 allele carriers relative to the epsilon3/3 allele subjects compared with subjects with IHD and control subjects combined was 0.44 (95% CI 0.21 to 0.93, P=0.021), and that compared with control subjects alone was 0.36 (95% CI 0.17 to 0.78, P=0.005), implying that the presence of the epsilon4 allele indicates resistance to the development of VSA. In contrast, people with the epsilon2 allele showed a tendency to develop VSA more frequently than did patients with IHD (P=0.009), although the frequency of the epsilon2 allele did not differ between patients with VSA and control subjects. On the other hand, no recessive and dominant effects of the D alleles on VSA were found. These findings suggest that the risk of the occurrence of VSA may be reduced by the epsilon4 allele and increased by the epsilon2 allele. The ApoE polymorphism may be associated with IHD and VSA, probably due to the modulation of lipid metabolism.

Adult↗

PubMed2000

Expression of three zebrafish Six4 genes in the cranial sensory placodes and the developing somites.

The homeobox gene Six4/AREC3 is a member of the vertebrate Six family of transcription factor genes. In this study we describe the cloning and expression of three zebrafish homologues of Six4/AREC3, six4.1, six4.2 and six4.3. These zebrafish Six4 proteins show high homology to the mammalian Six4/AREC3 proteins in the most C-terminal region in addition to the Six domain and homeodomain. Whole-mount in situ hybridization showed that six4.1 is expressed in the presumptive cranial placodal precursor cells, and later in the olfactory, otic and lateral line placodes. six4.2 is expressed in the presomitic mesoderm, somites and pectoral fin bud. six4.3 appears to be a unique member of the Six4 proteins and is expressed ubiquitously at gastrulation and later in the tectum.

Amino Acid Sequence↗

PubMed2000

Ascorbic acid improves postischemic vasodilatation impaired by infusion of soybean oil into canine iliac artery.

This study was conducted to (a) assess postischemic vasodilatation by changes in the vascular cross-sectional area using simultaneous intravascular two-dimensional and Doppler ultrasound before and after the infusion of Intralipid (Pharmacia & Upjohn, Peapack, NJ, U.S.A.); (b) evaluate how antioxidant ascorbic acid modifies the effects of Intralipid on postischemic vasodilatation: and (c) clarify the changes in plasma nitrite and nitrate (NOx-) levels after the infusion of Intralipid with and without ascorbic acid. Twenty-eight mongrel dogs were used to measure for vascular cross-sectional area and average instantaneous peak velocity in the iliac arteries after the 5-min occlusion of the arteries. Postischemic vasodilatation was impaired after the infusion of Intralipid (20%, 2 ml/kg) and this impaired response was reversed by the co-administration of ascorbic acid (30 mg/kg). NG-monomethyl-L-arginine completely abolished postischemic vasodilatation. Plasma NOx levels were significantly reduced after the infusion of Intralipid compared with baseline (11.6+/-0.4 vs. 12.9+/-0.3 microM, p = 0.025) and after infusion of Intralipid with ascorbic acid compared with baseline (11.8+/-0.5 vs. 13.1+/-0.4 microM, p = 0.047). We concluded that ascorbic acid reverses the endothelial dysfunction induced by Intralipid without increasing plasma NOx- levels and that deactivation of nitric oxide by oxidative stress is a primary contributor to Intralipid-induced impaired vasodilation.

Animals↗

PubMed2000

Simultaneous intravascular two-dimensional plus Doppler ultrasound is useful for evaluation of postischemic vasodilatation: plasm NOx - levels determined by the Griess method may not reflect the extent of postischemic NO-induced vasodilatation.

Our objective was 1) to assess postischemic vasodilatation using simultaneous intravascular two-dimensional and Doppler ultrasound, and 2) to clarify whether plasma nitrite and nitrate (NOx-) levels change during postischemic vasodilatation. The vascular cross-sectional area (CSA) was evaluated in 18 mongrel dogs, and the average instantaneous peak velocity (APV) in the iliac arteries after the 5-min occlusion of blood flow was determined. Plasma NOx- levels were measured at the baseline, during the occlusion of blood flow, and 1.5, 3, and 10 min after recanalization. The %CSA significantly increased from 30 s to 7 min after the recanalization, and maximal vasodilatation was observed at 1.5 min after the recanalization (14.1 +/- 0.9 to 15.8 +/- 1.0 mm2, p< 0.0001 vs. baseline). Plasma NOx- levels were significantly reduced during the occlusion of blood flow and remained reduced at 1.5, 3, and 10 min after recanalization compared with the baseline values. We concluded that simultaneous intravascular two-dimensional and Doppler ultrasound is useful for assessment during postischemic vasodilatation, and that plasma NOx- levels assayed with the Griess reagent do not significantly increase, even when maximal vasodilatation is observed.

Animals↗

PubMed2000

[Renomedullary interstitial cell tumor: a case report].

Renomedullary interstitial tumor is a common tumor in the renal medulla, present in 26-41% of consecutive autopsy specimens. However clinically evident case is infrequent because this lesion is usually small (less than 3 mm). We report a case of renomedullary interstitial tumor in a 76-year-old woman. Ultrasonogram incidentally revealed a mass in the left kidney while she visited to the hospital for hypertension and unstable angina. A CT scan showed a 2 cm mass that was not clearly enhanced. MR images showed low signal intensity in both T1 and T2 images. Arteriography demonstrated no neo-vascularity. Those findings showed that this lesion was benign one or hypovascular carcinoma. So Left nephrectomy was performed and histological examination revealed a renomedullary interstitial tumor.

Aged↗

PubMed2000

[A late phase II study of raltitrexed (ZD 1694) in chemotherapy-naive patients with advanced colorectal cancer].

A multicenter co-operative late phase II study of raltitrexed (ZD1694), a specific thymidylate synthase (TS) inhibitor, was conducted in chemotherapy-naive patients with advanced colorectal cancer. Raltitrexed was infused intravenously over 15 minutes once every three weeks. Between April 1996 and September 1998, 61 patients were enrolled and 58 were eligible. Fourteen patients experienced a partial response (PR), 22 no change (NC), 20 progressive disease (PD) and 2 no evaluable (NE). The overall response rate was 24.1% (95% CI: 13.9-37.2%). Responses were seen in lung (22.7%), liver (22.9%) and deep lymph nodes (10.0%). Median survival was 11.6 months. Grade 3 or 4 toxicities were: leukopenia (13.8%), neutropenia (24.1%), hemoglobin decrease (15.5%), FBC decrease (6.9%), hematocrit decrease (6.9%), thrombocytopenia (6.9%), transient SGPT increase (6.9%), nausea/vomiting (20.7%), anorexia (15.5%), and asthenia (6.9%). These adverse reactions were considered to be manageable. Only one death was associated with drug treatment. These results suggest that raltitrexed provides an effective and convenient treatment for patients with advanced and previously untreated colorectal cancer.

Adult↗

PubMed1999

Prostacyclin synthase gene transfer inhibits neointimal formation in rat balloon-injured arteries without bleeding complications.

OBJECTIVE: This study was designed to compare the effects of prostacyclin synthase (PCS) gene transfer with those of a systemic infusion of beraprost sodium (BPS), a prostacyclin analogue, on vascular smooth muscle cell (VSMC) proliferation and neointimal formation after arterial injury. METHODS: PCS gene (3 or 30 micrograms) was transfected into rat balloon-injured carotid arteries by a non-viral lipotransfection method. BPS (100 or 300 micrograms/kg/day) was subcutaneously infused with osmotic pumps after the injury. LacZ gene (30 micrograms) was used as a control. VSMC proliferation was estimated by the bromodeoxyuridine (BrdU) index (BrdU-positive nuclei/total nuclei) at day 7. Neointimal formation was evaluated at day 14. Each treatment group had six rats. RESULTS: PCS gene transfer prevented the increase in intimal/medial area ratio (3 micrograms: 46.6%, 30 micrograms: 61.1% reduction; P < 0.05, P < 0.01, respectively), as did BPS 300 micrograms/kg/day (49.8% reduction; P < 0.05). BPS 100 micrograms/kg/day, however, had no effects on the ratio. PCS gene transfer and BPS 300 micrograms/kg/day significantly suppressed the BrdU index. BPS 300 micrograms/kg/day group had more frequent hematoma and longer bleeding time. There were no significant differences in blood pressure, heart rate, or urinary volume among all groups. CONCLUSION: Both PCS gene transfer and BPS 300 micrograms/kg/day reduced neointimal formation after arterial injury by inhibiting VSMC proliferation. PCS gene transfer may be a safer therapeutic modality against neointimal formation than a systemic infusion of BPS because the former method resulted in fewer bleeding complications.

Analysis of Variance↗

PubMed1999

Altered gene expression of prostacyclin synthase and prostacyclin receptor in the thoracic aorta of spontaneously hypertensive rats.

OBJECTIVE: The aim of this study was to evaluate the possible role of prostacyclin (PGI2) in the pathogenesis of hypertension in spontaneously hypertensive rats (SHR). METHODS: Measurement of mRNA and protein levels of PGH synthase (PGHS)-1, PGI2 synthase and the PGI2 receptor, in the thoracic aorta was performed in SHR aged 5, 10, 20, and 40 weeks old and in age-matched normotensive Wistar-Kyoto (WKY) rats with a competitive polymerase chain reaction method and immunoblotting. Aortic production of 6-keto-PGF1 alpha, the main metabolite of PGI2, was also measured. RESULTS: Compared with age-matched WKY rats, PGHS-1 mRNA and protein levels in the thoracic aorta of SHR increased with age, reaching three- and twofold higher than WKY rats at 40 weeks old, respectively. PGI2 synthase mRNA and protein levels in SHR were significantly higher than in WKY rats at 20 and 40 weeks old. In contrast, PGI2 receptor mRNA levels in SHR were consistently lower than in WKY rats at all ages. CONCLUSIONS: These results provide evidence that hypertension elicits alterations in levels of arachidonic acid metabolites, including PGH2 and PGI2. They also suggest that the decreased expression of PGI2 receptor mRNA in prehypertensive SHR could be one of the causes of hypertension in SHR.

Aging↗

PubMed1999

Reduction of vascular tone by introduction of troglitazone to the canine coronary artery.

The insulin-sensitizing agent troglitazone ((+/-)-5-[4-(6-hydroxy-2,5,7,8-tetramethylchroman-2-ylmethoxy++ +)benzyl]-2,4- thiazolidinedione, CAS 97322-87-7), has been reported to reduce vascular tone in the rat tail artery. This study was designed to examine whether troglitazone could relax the precontracted canine coronary artery in vitro. Isometric tension of coronary arterial rings was measured, and analysis by Mann-Whitney U-test revealed that significant relaxation was induced even with 1 mumol/l troglitazone. This relaxation was not affected by blocking of NO synthase, cyclooxygenase, the large and intermediate conductance Ca(2+)-activated K+ channel, the ATP-sensitive K+ channel, or the Na(+)-K+ pump. The exact mechanism of the reduction of vascular tone by troglitazone remains unclear. However, the finding that troglitazone acts as a vasorelaxant in the coronary artery may be clinically useful, since troglitazone is mainly used for type II diabetic patients with insulin resistance, which is associated with increased risk for coronary artery disease.

Animals↗

PubMed1999

Oxygen-derived free radical-induced vasoconstriction by thromboxane A2 in aorta of the spontaneously hypertensive rat.

This study was performed to clarify the mechanism of vasoconstriction induced by oxygen-derived free radicals in spontaneously hypertensive rats. The isometric tension of aortic rings from spontaneously hypertensive rats and Wistar-Kyoto rats was measured in Krebs-Henseleit solution. Oxygen-derived free radicals were generated by mixing xanthine and xanthine oxidase. The removal of endothelium enhanced the contractions induced by oxygen-derived free radicals. The inhibition of nitric oxide production with NG-nitro-L-arginine methyl ester (10(-4) M) enhanced the contractions. Treatment with the thromboxane A2 (TXA2) synthetase inhibitor OKY-046 (10(-4) M) or RS-5186 (10(-4) M) markedly reduced the contractions. Treatment with the cyclooxygenase inhibitor indomethacin (10(-5) M) and a TXA2/prostaglandin H2 (PGH2) receptor antagonist, ONO-3708 (10(-6) M), completely abolished the oxygen-derived free radical-induced contractions. In contrast, treatment with the PGI2 synthetase inhibitor tranylcypromine (10(-4) M) did not attenuate the oxygen-derived free radical-induced contractions. Whether endothelium was present or not, the release of TXB2, PGE2, and 6-keto-PGF1alpha, but not PGF2alpha, was increased by the production of oxygen-derived free radicals. Catalase and the hydroxyl radical scavenger deferoxamine plus mannitol markedly inhibited the oxygen-derived free radical-induced contractions. These results suggest that oxygen-derived free radical-induced vasoconstriction in spontaneously hypertensive rat aorta is caused by TXA2 and PGH2 released in smooth muscle.

Animals↗

PubMed1999

Prostacyclin synthase gene transfer accelerates reendothelialization and inhibits neointimal formation in rat carotid arteries after balloon injury.

Prostacyclin (PGI2), a metabolite of arachidonic acid, has the vasoprotective effects of vasodilation, anti-platelet aggregation, and inhibition of smooth muscle cell proliferation. We hypothesized that an overexpression of endogenous PGI2 may accelerate the recovery from endothelial damage and inhibit neointimal formation in the injured artery. To test this hypothesis, we investigated in vivo transfer of the PGI2 synthase (PCS) gene into balloon-injured rat carotid arteries by a nonviral lipotransfection method. Seven days after transfection, a significant regeneration of endothelium was observed in the arteries transfected with a plasmid carrying the rat PCS gene (pCMV-PCS), but little regeneration was seen in those with the control plasmid carrying the lacZ gene (pCMV-lacZ) (percent luminal circumference lined by newly regenerated endothelium: 87. 1+/-6.9% in pCMV-PCS-transfected vessels and 6.9+/-0.2% in pCMV-lacZ vessels, P<0.001). BrdU staining of arterial segments demonstrated a significantly lower incorporation in pCMV-PCS-transfected vessels (7. 5+/-0.3% positive nuclei in vessel cells) than in pCMV-lacZ (50. 7+/-9.6%, P<0.01). Moreover, 2 weeks after transfection, the PCS gene transfer resulted in a significant inhibition of neointimal formation (88% reduction in ratio of intima/media areas), whereas medial area was similar among the groups. Arterial segments transfected with pCMV-PCS produced significantly higher levels of 6-keto-PGF1alpha, the main metabolite of PGI2, compared with the segments transfected with pCMV-lacZ (10.2+/-0.55 and 2.1+/-0.32 ng/mg tissue for pCMV-PCS and pCMV-placZ, P<0.001). In conclusion, this study demonstrated that an in vivo PCS gene transfer increased the production of PGI2 and markedly inhibited neointimal formation with accelerated reendothelialization in rat carotid arteries after balloon injury.

6-Ketoprostaglandin F1 alpha↗

PubMed1998

Usefulness of enhanced insulin secretion during an oral glucose tolerance test as a predictor of restenosis after direct percutaneous transluminal coronary angioplasty during acute myocardial infarction in patients without diabetes mellitus.

To determine predictive factors of the development of restenosis after percutaneous transluminal coronary angioplasty (PTCA), 25 nondiabetic nonobese patients aged <80 years old and 57 consecutive patients with successful direct PTCA with acute myocardial infarction were subjected to a 75-g oral glucose tolerance test (OGTT) and underwent follow-up coronary angiography 4 months later. The relation between the development of restenosis (late loss index: the decrease in the absolute minimal lumen diameter [MLD] at follow-up coronary angiography divided by MLD measured 1 day after PTCA) and the results of OGTT together with basic patient characteristics like age, body mass index, plasma levels of cholesterol, triglycerides, and high-density lipoprotein cholesterol were analyzed. Spearman's rank correlation analysis revealed that neither age, body mass index, nor plasma lipids correlated with late loss index, but only insulin area (p = 0.041) and insulin area/glucose area (p = 0.038) significantly correlated with the development of restenosis; a stepwise multiple regression analysis revealed that the insulin area was the only independent predictor of restenosis (p = 0.019). These results suggest that enhanced insulin secretion in response to glucose plays an important role in the development of restenosis after direct PTCA in non-diabetic patients, which may be through the direct action of insulin on smooth muscle cells of the coronary artery. This study also suggests the importance of performing OGTT for patients undergoing PTCA for the prediction of the development of restenosis.

Aged↗

PubMed1998

Gastric outlet syndrome caused by a gallstone: report of a case.

An extremely unusual case of gastric outlet syndrome, otherwise known as Bouveret's syndrome, caused by a large gallstone impacted in the duodenum due to a cholecystoduodenal fistula (CDF), is described herein. Another large gallstone impacted in the CDF itself was also detected. As endoscopic extraction of the gallstone from the duodenum proved unsuccessful, and a laparotomy was required. Our patient, being 88 years old, is probably the oldest patient recorded in the literature of this syndrome. The methods of establishing a correct diagnosis by endoscopy and recent therapeutic strategies are discussed following the case report.

Aged↗

PubMed1998

Radiotherapy in the management of Graves' ophthalmopathy.

BACKGROUND: To report the results of radiotherapy for patients with failure, adverse reactions or relative contraindications to the use of steroids or immunosuppressants, by using newly developed quantitative indexes. METHODS: Fourteen female and six male patients with Graves' ophthalmopathy were treated with radiotherapy between 1989 and 1996. Prior to radiotherapy, eight patients received treatment with prednisone, four received immunosuppressants and four received a combination of both. Four patients with contraindications to steroids were initially managed with radiotherapy. Most of the patients received a dose of 24-28 Gy in 2 Gy fractions. We used the newly developed motility limitation index to assess extraocular motility. RESULTS: Treatment was well tolerated. There have been no late complications. All 12 patients with soft tissue signs such as edema, irritation, tearing and pain were improved. Proptosis did not improve or improved only slightly, 3 mm at best. However, proptosis in all but two has been stabilized and has not deteriorated in the follow-up period. Most of the patients have experienced an improvement of eye-muscle motility. Extraocular muscles that work for elevation were impaired more severely than the other muscles and this tended to remain. Of the 16 patients using steroids before or when radiotherapy was initiated, 15 were tapered off and only one patient required additional steroids, thus sparing the majority from steroid adverse reactions. CONCLUSION: Radiotherapy was effective in preventing exacerbations of active inflammatory ophthalmopathy in patients with Graves' disease with minimal morbidity and thus eliminated the adverse reactions associated with protracted corticosteroid use. The newly developed motility limitation index was useful in detecting delicate changes in motility of individual extraocular muscles.

Adult↗

PubMed1997

Primary malignant lymphoma of the rectum with distant metastasis to the stomach: report of a case.

Primary extranodal malignant lymphoma frequently occurs in the gastrointestinal tract: however, it is rarely encountered in the rectum. We report herein the case of an 85-year-old man who underwent abdominoperineal resection for primary malignant lymphoma of the rectum, and 1 year later, developed hematemesis caused by gastric metastasis. To our knowledge this is the first case report of such distant metastasis developing from malignant lymphoma of the rectum.

Aged↗

PubMed1997

Anorectal malignant melanoma: report of a case.

A 74-year-old woman presented with anal bleeding and a protuberant mass. A biopsy of the mass revealed the proliferation of spindle-shaped cells with melanin pigments, and an abdominoperineal resection was performed, the histology of which confirmed malignant melanoma. Surgery was absolutely noncurative because massive metastases were encountered in the pelvic and paraaortic lymph nodes. However, postoperative chemotherapy, composed of decarbazine (DTIC), vincristine (VCR), and nimustine hydrochloride (ACNU), achieved satisfactory results. The patient has been well without any evidence of recurrence for more than 3 years.

Aged↗

PubMed1997

Relapse of colon cancer followed by polymyositis: report of a case and review of the literature.

The direct causal relationship between dermatomyositis-polymyositis (PM) and malignancy remains controversial. We describe herein the case of a patient who underwent surgical treatment for colon cancer, which had preceded the onset of PM with tumor relapse. The PM markedly improved following the initiation of steroid therapy, and has remained under control, probably as a result of chemotherapy. The current concepts of variable clinical courses and the possible mechanism for the association of PM with malignancy are discussed following this case report.

Adenocarcinoma↗