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Biomedical subjects

Y Takeuchi

Publications and source records attributed to Y Takeuchi.

At least 163 records · Page 9Linked to original sources
PubMed2000

Novel enantioselective fluorinating agents, (R)- and (S)-N-fluoro-3-tert-butyl-7-nitro-3,4-dihydro-2H-benzo[e][1,2]thiazine 1,1-dioxides.

Enantioselective fluorinating agents, (R)- and (S)-,N-fluoro-3-tert-butyl-7-nitro-3,4-dihydro-2H-benzo[e][1,2]thiazine 1,1-dioxides (BNBT-F, 2) are readily prepared in 3 steps from racemic 3-tert-butyl-7-nitro-3,4-dihydro-2H-benzo[e][1,2]thiazine 1,1-dioxides (5) via optical resolution and fluorination. These agents make accessible both enantiomers of optically active quaternary alpha-fluoro carbonyl compounds in modest to high enantioselectivities. X-ray crystallographic analysis of chiral 2 reveals a unique structure wherein the nitrogen atom is highly pyramidalized and fluorine occupies an axial position.

Crystallography, X-Ray↗
PubMed2000

Alpha-bromo-alpha,alpha-difluoroallyl derivatives as synthetic intermediate: nucleophilic substitution of alpha-bromo-alpha,alpha-difluoroallyl derivatives in the presence of palladium catalysts.

The palladium catalyzed nucleophilic substitution of alpha-bromo-alpha,alpha-difluoroallyl derivatives turned out to be an efficient method for the preparation of several fluorinated organic molecules. Several soft carbon nucleophiles regioselectively reacted with 3-bromo-3,3-difluoropropene (BDFP) to give the 3-substituted 1,1-difluoroalkenes. Phenylzinc chloride and tributylphenyltin afforded 1-fluoro-1,3-diphenylpropene. The radical bromination of 3-substituted 1,1-difluoroalkenes provided 1-substituted BDFPs, and a 1-substituted BDFP reacted with carbon nucleophiles to give 1,3-disubstituted 3,3-difluoroalkenes. For the reaction of nitrogen nucleophiles with BDFP, an amine and the sodium salts of the carbamates reacted with BDFP at the gamma-position. However, the sodium salts of the sulfoneamide predominantly attacked at the alpha-position.

Catalysis↗
PubMed2000

The aetiology of non-tumorous enhancement in the hepatic hilum shown on CT hepatic arteriography.

The causes of non-tumorous abnormalities in the hepatic hilum seen on CT hepatic arteriography were investigated. 13 patients with non-tumorous defects of portal perfusion in the hepatic hilum on CT arterial portography underwent both CT hepatic arteriography from the common hepatic artery and CT obtained during proper hepatic arteriography. The findings of non-tumorous portal defects on these two angiographic studies using helical CT were compared. In the 13 patients, 14 non-tumorous defects of portal perfusion in the hepatic hilum on CT arterial portography were detected as enhanced areas in 10 regions (dorsum of segment IV, 7/10; dorsum of the lateral segment, 3/4) on CT hepatic arteriography via the common hepatic artery, but none were enhanced on CT obtained during proper hepatic arteriography. In conclusion, the main cause of non-tumorous enhancement in the hepatic hilum seen on CT hepatic arteriography is non-portal direct inflow via the parabiliary venous system.

Aged↗
PubMed2000

Increased hepatic arterial blood flow after decreased portal supply to the liver parenchyma owing to intrahepatic portosystemic venous shunt: angiographic demonstration using helical CT.

This study was conducted to investigate the haemodynamics of the liver parenchyma in the presence of intrahepatic portosystemic venous shunt. 3 patients with intrahepatic portosystemic venous shunts and 24 patients with normal intrahepatic haemodynamics underwent both CT arterial portography and CT during hepatic arteriography. Angiographic findings with helical CT were compared, and CT attenuated values were measured in both groups. The liver parenchyma on CT arterial portography had lower attenuation than on CT during hepatic arteriography in all patients with intrahepatic portosystemic venous shunts. Overall average CT attenuation was 92.2 +/- 7.7 Hounsfield units (HU) on CT arterial portography and 149.9 +/- 8.5 HU after CT during hepatic arteriography, with the opposite findings in all patients without intrahepatic portosystemic venous shunt: CT attenuation 142.0 +/- 25.7 HU on CT arterial portography and 100.7 +/- 16.4 HU after CT during hepatic arteriography. In conclusion, the portal venous supply to the liver parenchyma decreased due to intrahepatic portosystemic venous shunts, with a compensatory increase in hepatic arterial blood supply.

Adult↗
PubMed2000

Sex determination based on fecal DNA analysis of the amelogenin gene in sika deer (Cervus nippon).

A sex determination method using DNA extracted from feces has been developed for sika deer (Cervus nippon). We determined a partial sequence of the amelogenin gene of sika deer, which exists on both X and Y chromosomes with a deletion region on the Y chromosome. Based on the sexually dimorphic sequences, we designed a pair of primers which could amplify DNA fragments the lengths of which are different between males and females. PCR products were detected in 34 out of 37 fecal samples collected from captured deer and the sexes estimated by the present method were perfectly matched with the actual sexes.

Amelogenin↗
PubMed2000

Revealing hepatic metastases from colorectal cancer: value of combined helical CT during arterial portography and CT hepatic arteriography with a unified CT and angiography system.

OBJECTIVE: The purpose of our study was to evaluate the use of combined helical CT during arterial portography and CT hepatic arteriography in the preoperative assessment of hepatic metastases from colorectal cancer using a unified CT and angiography system. MATERIALS AND METHODS: Fifty-four patients with hepatic metastases from colorectal cancer preoperatively underwent combined CT during arterial portography and CT hepatic arteriography using the unified CT and angiography system. Three radiologists independently and retrospectively reviewed the images of CT during arterial portography alone, CT hepatic arteriography alone, and combined CT during arterial portography and CT hepatic arteriography. Image review was conducted on a segment-by-segment basis; a total of 432 hepatic segments with (n = 103) 118 metastatic tumors ranging in size from 2 to 160 mm (mean, 25.8 mm) and without (n = 329) tumor were reviewed. RESULTS: Relative sensitivity of combined CT during arterial portography and CT hepatic arteriography (87%) was higher than that of CT during arterial portography alone (80%, p < 0.0005) and CT hepatic arteriography alone (83%, p < 0.005). Relative specificity of CT hepatic arteriography alone (95%, p < 0.0005) and combined CT during arterial portography and CT hepatic arteriography (96%, p < 0.0001) was higher than that of CT during arterial portography alone (91%). Diagnostic accuracy, determined by a receiver operating characteristic curve analysis, was greater with combined CT during arterial portography and CT hepatic arteriography than with CT during arterial portography alone (p < 0.05) or CT hepatic arteriography alone (p < 0.01). CONCLUSION: Using a unified CT and angiography system, we found that combined CT during arterial portography and CT hepatic arteriography significantly raised the detectability of hepatic metastases from colorectal cancer.

Adult↗
PubMed2000

Sympathetic fibers innervating the extraocular muscles: cells of origin in the cat superior cervical ganglion.

Cells of origin of sympathetic fibers innervating the extraocular muscles were demonstrated in the cat superior cervical ganglion (SCG) using the horseradish peroxidase (HRP) technique. Each injection of HRP into the muscles was confirmed by labeling in the oculomotor, trochlear and abducens nuclei. In all cases retrogradely labeled neurons were found to be distributed widely to the ipsilateral SCG. Labeled neurons were round or oval in shape and majority of these were medium in size. There were some large-sized neurons which frequently showed to have long dendrites expanding rostrocaudally. The labeling was characterized by localization in the rostral two-thirds of the SCG after HRP injections into the medial, lateral and inferior and superior oblique muscles. However, the labeling was found in the whole of the SCG after HRP injections into the superior rectus and inferior oblique muscles. Compared with our previous studies demonstrating cells of origin of the sympathetic fibers in the facial and hypoglossal nerves, the present experiments showed quite different pattern of distribution of labeled neurons in the SCG.

Adrenergic Fibers↗
PubMed2000

The effects of prenatal X-irradiation on hypoglossal nucleus: a GFAP immunohistochemical study.

The effects of prenatal X-irradiation on hypoglossal (XII) nucleus were investigated in the rat. Pregnant animals were exposed to a single whole body X-irradiation on day 11 and 16 of gestation at a does of 1.3 Gy. The offspring were killed at 7-14 days of age for the histological and immunohistochemical observations. Nissl staining revealed no significant changes of XII motoneurons in these experimental animals. In the control case it was of interest that expression of glial fibrillary acidic protein-immunoreactivity (GFAP-IR) is largely confined to the dorsomedial region including the XII nucleus at the level caudal to the obex. Exposure of X-irradiation on day 16 of gestation led to similar expression of GFAP-IR in the nucleus at the same level. However, exposure on day 11 of gestation apparently led to strong expression of GFAP-IR in the XII nucleus at the level caudal to the obex and the expression was observed to extend rostrally. The GFAP-IR cells showed hypertrophy of cell bodies and longer cytoplasmic processes. Horse-radish peroxidase (HRP) injection into the tip of the tongue including the intrinsic muscles resulted in retrograde labeling in the ventromedial portion of the XII nucleus bilaterally from +0.30 to -1.25 mm. The present study would indicate that motoneurons of the XII nucleus supplying mainly the intrinsic and partly the extrinsic tongue muscles are more sensitive to X-ray exposure before the formation of the XII nucleus.

Animals↗
PubMed2000

Changes in dopamine transporter and c-Fos expression in the nucleus accumbens of alcohol-tolerant rats.

BACKGROUND: We have shown that neurochemical functions of 5-HT3 receptors in regulating dopamine (DA) release in the nucleus accumbens (ACC) after alcohol exposure compensate for the dysfunction of serotonergic activity to restore the original properties in processing alcohol tolerance, and that the development of alcohol dependence may be mediated by ACC 5-HT3 receptors. In the present study, the effects of chronic alcohol consumption on the functions of the dopamine transporter (DAT) and the expression of c-Fos proteins were investigated using in vivo brain microdialysis and immunocytochemistry. METHODS: Perfusion of cocaine and 1-(2-Bis-(4-fluorophenyl) methoxy) ethyl)-4-(3-phenylpropyl) piperizine (GBR 12909) through the microdialysis probe membrane increased the extracellular levels of DA in ACC of alcohol-treated rats that had developed alcohol tolerance by drinking 10% EtOH for 30 days. RESULTS: The magnitudes of DA reuptake or DAT inhibitors, cocaine, and GBR 12909 that induced DA availability in the ACC were significantly higher in alcohol-treated rats than in controls. When compared with control rats, the alcohol-treated rats exhibited higher levels of DA and its metabolite, DOPAC, in the ACC. Increased expression of the c-Fos-like protein was found in the ACC of alcohol-treated rats. These results show that (1) chronic alcohol consumption desensitizes or decreases the DAT of DA terminals in the ACC and that (2) EtOH causes cellular hyperexcitability of ACC dopaminergic neurons with increased Fos expression during alcohol tolerance. CONCLUSION: The findings suggested that an abnormality of the dopaminergic neurons in the ACC that are involved with DAT dysfunction is associated with the development of alcohol tolerance.

Alcoholism↗
PubMed2000

Immunohistochemical study on acetaldehyde adducts in alcohol-fed mice.

BACKGROUND: Acetaldehyde binds to some proteins, which results in Schiff base formation. It is assumed that acetaldehyde binds to the proteins after the consumption of ethanol, to form an adduct. Such acetaldehyde adducts are related to organ disease. METHODS: We examined 8-week-old male BALB/c mice, which were given a liquid diet for 7 days. The diet consisted of vitamins, minerals, amino acids, and a 5% (v/v) ethanol solution. After the 7 days, we took tissue samples from the brain, liver, and adrenal cortex to investigate the distribution of acetaldehyde adducts. We performed immunohistochemical staining of the cerebral cortex, liver, and adrenal cortex from the mice by using antibodies against acetaldehyde adducts. RESULTS: Our study showed that acetaldehyde adducts formed in the cerebral cortex in the early phase in alcohol-fed mice. CONCLUSIONS: Because acetaldehyde in the liver has been shown to cause liver damage, our study suggests a relationship between acetaldehyde adducts in the brain and brain damage.

Acetaldehyde↗
PubMed2000

[Brainstem hemorrhage following acute necrotizing encephalopathy].

We report here a case of acute necrotizing encephalopathy (ANE) showing brainstem hemorrhage. A 5-year-11-month-old boy with a history of febrile seizures was admitted to our hospital because of high fever and coma. Laboratory studies on admission demonstrated elevated serum transaminase and blood glucose. Brain CT was normal on admission, but 9 hours later, it showed low density areas in the bilateral thalamus, putamen, midbrain, pons and cerebellum. Brain MRI revealed abnormal short T1 and long T2 signals in the same areas. Despite promptly performed intensive care, massive brainstem hemorrhage occurred on the fourth day. EEG showed a suppression-burst pattern followed by a flat pattern on the sixth day. The patient died on the eighth day of multiple organ failure. This is the first case of massive brainstem hemorrhage that occurred in association with ANE.

Brain Stem↗
PubMed2000

[A patient with choreoathetosis of the left upper extremity due to acute cerebral infarction].

A 71-year-old woman was admitted to our hospital because of involuntary movement of the left upper extremity. MR image of the brain 15 days after the onset revealed the low intensity in right posterior limb of internal capsule. The lesion was surrounded by thalamus, subthalamic nucleus, and globus pallidus with enhancement by Gd-DTPA. Surface EMG revealed irregular grouped discharge in short duration and grouped discharge in long duration in the left upper extremity. Those features are compatible with one of choreoathetosis. Choreoathetosis due to cerebral infarction in acute phase is rare. We discussed pathophysiology of this involuntary movement due to lacunar infarction of posterior limb of internal capsule in acute phase.

Aged↗
PubMed2000

Germ cell-specific expression of green fluorescent protein in transgenic rainbow trout under control of the rainbow trout vasa-like gene promoter.

A technique to identify and isolate live fish primordial germ cells (PGCs) has not been established, in spite of the importance of purified germ cells for molecular and cellular studies. In rainbow trout, the distribution of vasa transcripts is restricted to the germ cell lineage, making this transcript a useful indicator of PGCs. Therefore, in this study, we cloned and characterized the rainbow trout vasa-like gene (RtVLG) regulatory regions and produced transgenic trout carrying the green fluorescent protein (GFP) gene driven by the RtVLG regulatory regions (p vasa-GFP) in order to identify live PGCs in vivo. In transgenic trout carrying the p vasa-GFP construct, cells showing green fluorescence were first observed at the mid-blastula stage; however, no cell-type-specific expression was observed at this stage. At the eyed stage, about 30% of the transgenic embryos showed specific GFP expression in PGCs, and at the hatching stage, about 70% of the transgenic embryos did so. An immunohistochemical study of hatching stage embryos revealed that the GFP-expressing cells are located in genital ridges. This transgenic trout, having visualizable PGCs, will make it possible to isolate live PGCs for in vitro studies and to study the ontogeny of PGCs including sex differentiation in live embryos.

Animals↗
PubMed2000

[Coronary artery bypass grafting using side-to-side anastomosis].

Recently, to obtain better long-term patency after coronary artery bypass grafting (CABG) arterial conduits such as internal mammary arteries (IMAs) and the right gastroepiploic artery have been frequently used. For coronary site anastomosis, end-to-side anastomosis is common. These conduits have a smaller diameter than the saphenous vein graft, so that, usually, longitudinal slits are made on the distal end of these grafts to obtain a more effective anastomotic orifice area. However, there is a potential for anastomotic leakage due to mismatch between the incision of the coronary artery and the arterial graft. We report here the efficacy of side-to-side anastomosis using small arterial conduits. This method has several advantages. Firstly, there is no chance of anastomotic leakage, since the coronary incision and graft incision can be perfectly matched. Secondly, if there is at least a 5-mm distance between the distal end of the graft incision and the surgical clip, the graft incision can be extended during anastomosis for adjustment. Thirdly, the distal end of the graft can be held beyond the surgical clip by forceps without damaging the arterial graft, which makes it easier for the anastomosis to be performed. Finally, the anastomosis can be checked by passing a probe through the distal end of the graft after removing the surgical clip. Also dye can be injected from the distal end of the graft at "Off Pump CABG", intraoperatively. This technique can be applied not only for distal end anastomosis, but also for proximal end, using free IMA to the ascending aorta and to make a Y-graft.

Anastomosis, Surgical↗
PubMed2000

[Porencephaly].

Explore the source record for details and available documents.

Brain↗
PubMed2000

[Considerations for community nursing care of the young advanced cancer patient].

In our unit and in general, nurses commonly take care of elderly patients. However, we herein describe the provision of community nursing care directed towards young advanced cancer patients. From our experience, the following issues should be considered by the medical care team for community nursing to be effective with these patients: Full explanation of treatment to enable the patient to make an informed decision. This can be achieved through provision of full details of the potential benefits and risks of community nursing. Next is the importance of a team based approach by the medical care team, with the support of various community and volunteer networks if necessary. Palliative care community nursing requires sincere and caring character profiles. In addition, we recognize that there are special considerations for home nursing care of the younger patient that are not present in our experience with the older patient group. One issue is that these patients have particular requirements which incur significant expenses for which there are few public support systems.

Adult↗