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S Yoshioka

Publications and source records attributed to S Yoshioka.

At least 127 records · Page 7Linked to original sources
PubMed1997

Near-infrared spectroscopic method for assessing the tissue oxygenation state of living lung.

To quantify changes in tissue oxygenation of pathologic lungs, we applied a novel method using near-infrared spectroscopy (NIRs). In in vitro experiments, we assayed the effect of photon scattering on the absorption spectra of an in vitro system simulating structures of lung, which consists of test tube containing air in hematocrit tubes and red blood cell suspension with various predetermined hemoglobin concentrations. It was determined that photon scattering of the tissue containing air did not affect the absorption in the NIR region. In in vivo experiments, we tested the applicability of the NIRs technique in rat lungs under the following conditions: (1) hypoxic loading; (2) administration of an inhibitor (NaCN) of the mitochondrial respiratory chain; (3) hemorrhagic shock. We found that: (1) Changes in hemoglobin oxygenation state in the lung measured by NIRs depended on inspired oxygen concentrations; (2) NaCN-induced reduction of cytochrome oxidase a,a3 in the lung was observed; and (3) Total hemoglobin levels in the lung decreased after bleeding. Changes in the hemoglobin oxygenation state and cytochrome oxidase redox state in the lung were determined using the least-square-curve fitting for NIR absorption spectra. Our NIRs technique was capable of assessing the hemoglobin oxygenation and cytochrome oxidase redox state in the lung.

Animals↗
PubMed1997

The pressor response induced by repeated injections of neostigmine into the central nervous system is desensitized in adrenalectomized, but not in intact rats.

To investigate whether or not pressor responses to repeated stimulation of central cholinoceptive neurons are desensitized, mean arterial blood pressure (MAP) and heart rate (HR) were measured following repeated injections of neostigmine, an acetylcholinesterase inhibitor, into the third cerebral ventricle in conscious, unrestrained intact or adrenalectomized (ADX) rats. Neostigmine (5 x 10(-9) or 5 x 10(-8) mol) in 1 milliliter saline increased MAP dose-dependently and increased HR in intact rats. The peak values in MAP and HR after three repeated injections at 4 hour intervals did not wane. Neostigmine (5 x 10(-8) mol) also increased MAP in ADX rats, and the peak values after the first injection were higher in the ADX rats than in the intact rats. The pressor responses to the second and third injection, however, were less than to the first injection in the ADX rats. HR responses to the repeated injections in the ADX rats were identical to those in the intact rats. These findings suggest that the adrenal gland plays a role in antagonizing the development of desensitization in the neostigmine-induced pressor response.

Adrenalectomy↗
PubMed1997

Hepatic resection of liver metastases from gastric carcinoma.

OBJECTIVES: Previous reports have indicated that results of the surgical resection of hepatic metastases from gastric carcinoma have been unsatisfactory. We therefore evaluated the results of aggressive surgical resection for hepatic metastases from gastric carcinoma, to identify candidates with a better likelihood of survival. METHODS AND RESULTS: Twenty-one patients with synchronous or metachronous hepatic metastases from gastric carcinoma underwent hepatic resections. Five patients were still alive, without recurrence, at 10, 41, 46, 117, and 176 months after their hepatic resection. Sixteen patients died of recurrence 5-33 months (mean, 10 months) after hepatic resection. A significant difference in the number of node metastases (solitary or multiple) and in the tumor-free margin of the resection (< 10 mm or > 10 mm) was found between survivors and those who died. CONCLUSION: Hepatic resection for hepatic metastases from gastric carcinoma may improve the prognosis in patients with a solitary metastasis if adequate tumor-free margins (> 10 mm) can be obtained.

Aged↗
PubMed1997

SPECT imaging of normal subjects with technetium-99m-HMPAO and technetium-99m-ECD.

UNLABELLED: Technetium-99m-HMPAO and 99mTc-ECD have been used for regional cerebral blood flow (rCBF) studies using SPECT. However, details of the normal perfusion patterns of these agents still remain to be clarified. HMPAO-SPECT and ECD-SPECT images of normal individuals were investigated using an anatomical standardization technique. METHODS: Twenty healthy subjects participated in this study. In 10 of these, regional cerebral perfusion was measured with HMPAO, and in the other 10, ECD was used. All SPECT images were globally normalized to 50 counts/voxel, and then, each SPECT image was transformed into a standard brain anatomy format with the aid of x-ray CT of each subject and a computerized human brain atlas system (HBA). Mean and s.d. images for each tracer were calculated on a voxel-by-voxel basis. For comparison of these SPECT images with blood flow, rCBF images were generated using PET in a separate group of 10 healthy male subjects during an eyes-closed resting state. The PET images were globally normalized to 50 ml/100 g/min and anatomically standardized using each subject's MRI and the HBA for the SPECT images. RESULTS: In the HMPAO-SPECT images, relatively high radioactivities Were observed in the basal ganglia and cerebellum. In the ECD-SPECT images, high levels were observed in the medial aspect of the occipital lobe. These regions with high radioactivity were not apparent in the rCBF-PET images. CONCLUSION: While both HMPAO and ECD have been used to investigate rCBF, their perfusion patterns differ from rCBF-PET images. This presumably reflects differences in the mechanism of accumulation of each agent in the brain. For clinical diagnoses, these patterns must be taken into consideration.

Adult↗
PubMed1997

Laparoscopic transhiatal esophagectomy for advanced thoracic esophageal cancer.

We performed transhiatal subtotal esophagectomy under laparoscopic guidance to reduce the invasiveness of subtotal esophagectomy while preserving dissectional accuracy. In six cases of advanced thoracic esophageal cancer with distant metastasis, we used a special type of handpiece of ultrasonic surgical aspirator (CUSA) for laparoscopic surgery to dissect the esophagus from surrounding tissues and to isolate vessels entering it while viewing with the video monitor. Hemostasis of isolated vessels was effected by clips or electrocoagulation. There was no massive bleeding from the mediastinum during the operation, nor was there postoperative bleeding or infection. All patients regained normal swallowing ability and were discharged. Transhiatal esophagectomy under laparoscopic guidance is considered a safe, less invasive operative treatment for patients who are suffering from advanced thoracic esophageal cancer.

Aged↗
PubMed1997

[Pulmonary metastasis after resection of non-invasive thymoma: a case report--analysis of nuclear DNA pattern and pathological findings].

After resection of a non-invasive thymoma, two metastatic lung tumors were found in the left upper lobe and the left lower lobe. There were differences in tumor doubling time (TDT) and invasion between the metastatic tumor in the lower lobe and the one in the upper lobe. The TDTs of the tumors were 834.1 days and 328.3 days, and the tumor of the left lower lobe invaded the left lateral basal segmental bronchus (B9). The differences in the two tumors were determined by pathological findings and nuclear DNA pattern. Pathologically, the resected thymoma and both of the metastatic tumors were mixed type, which consisted of epithelial cells and lymphocytes. But by epithelium form, the resected thymoma and the tumor in the lower lobe were classified as cortex type, and only the slow growing tumor in the upper lobe contained a spindle-cell component. The DNA pattern of the resected thymoma was aneuploid and the two metastatic tumors were diploid. As this case is very interesting clinically and pathologically, we reported it.

Cell Division↗
PubMed1996

Functional anatomy of GO/NO-GO discrimination and response selection--a PET study in man.

The purpose of this study was to identify the functional fields activated in relation to the NO-GO decision. Nine healthy subjects participated in the study which consisted of two test positron emission tomography (PET) scans (GO/NO-GO task and response selection task) and one control scan. In the response selection task, subjects were asked to flex their thumb of the right hand when a light emitting diode (LED) placed 60 cm from their eyes turned on red and to flex their index finger of the right hand when LED turned on green. In the GO/NO-GO task, subjects were asked to flex their thumb when the LED turned on red, however, they were asked not to move their fingers when LED turned on green. In the control state, they were asked simply to look at the LED without any movement of finger during the course of the scan. The mean regional cerebral blood flow (rCBF) change images for each task minus control and task minus task were calculated and fields of significant rCBF changes were identified. Several fields in the prefrontal cortex of the right hemisphere were specifically activated in relation to the GO/NO-GO task. The results indicate that the prefrontal cortex of the right hemisphere may be a key structure to make a decision not to move.

Adult↗
PubMed1996

Topographic representation in human intraparietal sulcus of reaching and saccade.

Regional cerebral blood flow was measured by positron emission tomography in seven subjects during reaching with saccade, reaching without saccade, saccade and control tasks. The reaching with saccade task activated two spatially distinct areas in the contralateral intraparietal sulcus (IPS) compared with the control condition. The area located in the anterior part of the IPS was also activated during the reaching without saccade but not during the saccade task. The other area, located in the posterior part of the IPS was, in contrast, active during the saccade but not the reaching without saccade task. The results indicate that the human IPS is functionally heterogeneous, and that functional roles of its anterior and posterior parts include control of reaching movements and eye movements, respectively.

Adolescent↗
PubMed1996

Changes in regional cerebral blood flow during self-paced arm and finger movements. A PET study.

The purpose of this study was to identify the functional fields activated in relation to the self-paced proximal and distal arm movements. The regional cerebral blood flow (rCBF) was measured with positron emission tomography (PET) and 15O-labelled H2O (H2(15)O) in eight healthy subjects. All subjects performed the following three tasks: (1) repetitive opposition of thumb and index finger of the right hand, (2) repetitive co-contraction of biceps and tricepts brachii muscles of the right arm, and (3) rest. The mean rCBF change images for each task minus control was calculated and fields of significant rCBF changes were identified. Each movement activated different fields in the primary motor area (MI), the dorsal aspect of the premotor area (PMA) and the superior part of the prefrontal area (PFA) of the contralateral hemisphere. In these areas, arm fields were located relatively dorsally to the finger fields. In addition, specific fields in the ventral part of the PMA, the supplementary motor area (SMA), the superior parietal lobule (SPL) of the contralateral hemisphere, and the ipsilateral PFA were consistently activated during both movements. Due to a limited a field of view of the PET scanner in the axial direction, the PET scan could not cover the cerebellum. The results indicate that there may be somatotopical organization not only in the MI but also in the dorsal part of the PMA and the PFA, and that the specific fields in the ventral part of the PMA, the SMA, the SPL, and the PFA may be involved in self-paced movement.

Adult↗
PubMed1996

Pharmacokinetics of omeprazole (a substrate of CYP2C19) and comparison with two mutant alleles, C gamma P2C19m1 in exon 5 and C gamma P2C19m2 in exon 4, in Japanese subjects.

The pharmacokinetic profile of omeprazole was examined in 27 healthy Japanese volunteers, and the results were analyzed in relation to genotype for the two mutations, CgammaP2C19m1 in exon 5 and CgammaP2C19m2 in exon 4, associated with the poor metabolizer phenotype. Of the 27 individuals analyzed, 10 were homozygous for the wild-type (wt) allele in both exon 5 and exon 4 (wt/wt; 37.0%, pattern GI), five were heterozygous for the CgammaP2C19m1 (wt/m1; 18.5%, G2), five were heterozygous for the CgammaP2C19m2 (wt/m2; 18.5%, G3), two were heterozygous for the two defects (m1/m2; 7.4%, G4), and five were homozygous for the CgammaP2C19m1 (m1/m1; 18.5%, G5). The allele frequencies of the m1 and m2 mutation were 0.31 and 0.13, respectively. A correlation between the rate of metabolism of omeprazole and genotype was observed. The mean clearance values of omeprazole in patterns G1, G2, G3, G4, and G5 were 1369.0, 332.7, 359.0, 70.8, and 89.5 ml/hr/kg, respectively. The relative area under the serum concentration-time curve (AUC) ratio of omeprazole to 5-hydroxyomeprazole in patterns G1, G2, G3, G4, and G5 was 1:2.8:3.4:16:17.2. A similar relation was observed in the omeprazole/5-hydroxyomeprazole serum concentration ratio, determined 3 hours after drug intake (1:3:4:18.8:20.3). There were significant (p < 0.05 to 0.01) differences in the disposition kinetics of omeprazole between the subjects with patterns G1, G2, and G3 and the subjects with patterns G4 and G5. The results indicate that the 5-hydroxylation pathway of omeprazole is clearly impaired in subjects with m1/m2 and m1/m1.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed1996

Determination of molecular mobility of lyophilized bovine serum albumin and gamma-globulin by solid-state 1H NMR and relation to aggregation-susceptibility.

PURPOSE: Feasibility of solid-state 1H NMR for determining the mobility of protein molecules in lyophilized cakes was considered. The mobility in cakes with various levels of water content was studied in relation to aggregation-susceptibility. METHODS: Spin-spin relaxation time T2) of protons in lyophilized bovine serum albumin (BSA) and gamma-globulin (BGG) was measured as a function of hydration level by solid state 1H NMR using a 'solidecho' pulse sequence. Moisture-induced aggregation of the lyophilized proteins was also determined by high performance size exclusion chromatography. RESULTS: Lyophilized BSA and BGG became susceptive to aggregation when water content exceeded about 0.2 g/g of protein. T2 of protein protons in the lyophilized cakes started to increase at lower water contents. The increase in aggregation susceptibility observed with increasing water content appears to follow the increase in T2 of protein protons. For lyophilized BGG, both aggregation and T2 of protein protons decreased at water contents above 0.5 g/g protein. CONCLUSIONS: Mobility of protein molecules in lyophilized cakes was successfully determined by solid-state 1H NMR. The aggregation susceptibility of proteins was strongly related to their molecular mobility as indicated by T2.

Chemistry, Pharmaceutical↗
PubMed1996

Effects of sugars and polymers on crystallization of poly(ethylene glycol) in frozen solutions: phase separation between incompatible polymers.

PURPOSE: This study examined the effect of third components (low-molecular-weight saccharides and polymers) on the crystallization of poly(ethylene) glycol (PEG) in frozen solutions, focusing on the relationship between their crystallization-inhibiting ability and molecular compatibility. METHODS: Effects of sugars and polymers on the crystallization of PEG 3000 in frozen solution were monitored by differential scanning calorimetry (DSC). Pulsed-NMR was employed to monitor the molecular mobility of water and solutes in the frozen solutions. Miscibility between PEG and third components in aqueous solution was estimated from the lowering of cloud point of PEG 20,000. Thermal analysis of frozen solutions containing some non-crystallizing solutes was used to examine the possibility of phase separation in frozen solutions. RESULTS: Some sugars and polymers inhibited the crystallization of PEG and formed practically stable amorphous phases among ice crystals. The mobility of solute molecules in the amorphous phase increased above the softening temperature of maximally concentrated solutions (Ts), whereas that of water molecules appeared at a lower temperature. Mono- and disaccharides that are relatively less miscible with PEG in solution inhibit PEG crystallization to a lesser degree. Two Ts regions were observed in frozen solutions containing both polyvinylpyrrolidone (PVP) and dextran, at much lower concentrations than those causing aqueous two-phase separation at ambient temperatures. CONCLUSIONS: Ice crystallization raises the concentration of solutes in the remaining solution, which can lead to phase separation in the amorphous phase. Molecular compatibility between components is an important factor determining their propensity to phase separate and crystallize.

Calorimetry, Differential Scanning↗
PubMed1996

Molecular cloning and characterization of a novel isoform of the human UDP-galactose transporter, and of related complementary DNAs belonging to the nucleotide-sugar transporter gene family.

We described recently the molecular cloning of human UDP-galactose transporter 1 (hUGT1) [Miura, N. et al. (1996) J. Biochem. 120, 236-241]. Now we have characterized its isoform, hUGT2, that is most likely generated through the alternative splicing of a transcript derived from the UGT genomic gene, that also codes for hUGT1. Introduction of the open reading frame sequence of hUGT2 into a mouse cell line, Had-1, that lacks the UDP-galactose transporter, complemented the genetic defect of the mutant, as judged from the lectin-sensitivity spectra of the transformants and the nucleotide-sugar transporting activity of microsomal vesicles isolated from them. UGT-related genes were found through a BLAST search of dbEST based on their significant similarity with hUGT genes. We report here cDNA clones belonging to two subfamilies of the nucleotide-sugar transporter gene family. One is the human CMP-sialic acid transporter gene, and the other is a group of homologous genes with an undefined function that are distributed in man, mouse, and rat, and show significant similarity to the yeast UDP-N-acetylglucosamine transporter.

Amino Acid Sequence↗
PubMed1996

Benign external hydrocephalus in a boy with autosomal dominant microcephaly.

In a 3-month-old boy with microcephaly, magnetic resonance imaging (MRI) revealed accumulation of bifrontal extracerebral fluid. Because of the typical MRI findings and the disappearance of these findings later on, he was diagnosed as a case of benign external hydrocephalus. Both his mother and maternal grandmother had microcephaly, without neurological or dysmorphic manifestations. The pedigree is most consistent with an autosomal dominantly inherited microcephaly. This seems to be the first report of benign external hydrocephalus found in a patient with an autosomal dominant microcephaly.

Adult↗
PubMed1996

Reduced hepatic functional reserve in cirrhosis and obstructive jaundice with special reference to histological morphometric analysis and galactose elimination capacity.

To evaluate liver dysfunction in patients with obstructive jaundice (OJ), morphological and functional hepatic mass was analyzed in comparison with cirrhosis (LC). Total hepatic parenchymal ratio (THPR) was estimated by morphometric analysis and hepatic functional mass by galactose tolerance test (GaTT) in 30 patients who underwent hepatectomy. The value of GaTT in patients with LC was remarkably depressed compared to those with normal liver function (p < 0.001). It was also depressed in OJ (p < 0.05 vs. normal liver), but less than in LC (p < 0.05). However, THPR decreased only in LC (p < 0.05 vs. either normal liver or OJ). A significant correlation between the value of GaTT and THPR was revealed in patients with LC, but not in OJ. These results suggested that liver dysfunction in OJ was independent of the decreased number of hepatocytes, differing from LC.

Adult↗
PubMed1996

[Normal cerebral perfusion of 99mTc-ECD brain SPECT--evaluation by an anatomical standardization technique].

A single photon emitter labeled tracer, 99mTc-ethyl cysteinate dimer (99mTc-ECD), has now been used for rCBF studies with SPECT. However, normal distribution pattern of this agent in the brain still remains unclear. Therefore, the specific purpose of this study was to investigate the normal distribution pattern of 99mTc-ECD SPECT image. Regional cerebral distribution was measured with SPECT and 984 +/- 17 MBq of 99mTc-ECD in ten normal subjects. During the SPECT measurement, subjects were placed comfortably in a supine position with their eyes closed. Each SPECT image was anatomically standardized using a computerized brain atlas system of Roland et al. (HBA: Human Brain Atlas) and X-CT image. Anatomically standardized SPECT images were globally normalized to 100 count/voxel. Then, the mean and SD images of brain SPECT were calculated voxel-by-voxel basis. The highest radioactivity was found in the medial aspect of the occipital lobe. The results indicate that the normal distribution pattern of 99mTc-ECD in the human brain may be not simply reflect the regional cerebral blood flow.

Adult↗