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Biomedical subjects

Y Saitoh

Publications and source records attributed to Y Saitoh.

At least 55 records · Page 3Linked to original sources
PubMed2001

Nicorandil accelerates recovery of neuromuscular block caused by vecuronium.

PURPOSE: To examine the effect of nicorandil, a K ATP channel agonist, on neuromuscular block caused by vecuronium in patients anesthetized with nitrous oxide, oxygen, isoflurane, and fentanyl. METHODS: Sixty adult patients were allocated to four groups of 15: nicorandil-post-tetanic count (N-PTC), nicorandil-train-of-four (N-TOF), control-post-tetanic count (C-PTC) or control-train-of-four (C-TOF) group. In the N-PTC and N-TOF groups, 0.1 mg kg nicorandil was given as a bolus followed by an infusion at 1 microg x kg(-1) x min(-1). Two minutes after the bolus, 0.1 mg x kg(-1) vecuronium was administered. In the C-PTC or C-TOF group normal saline was given instead of nicorandil. PTC and TOF responses were measured mechanically using a force displacement transducer. RESULTS: Time from the administration of vecuronium to the onset of neuromuscular block in the N-PTC or N-TOF group did not differ from that in the C-PTC or C-TOF group (241 +/- 33 vs 225 +/- 32 sec, mean +/- SD). Times from vecuronium injection to the return of PTC in the N-PTC and C-PTC groups, and those of T1, T2, T3, and T4 (first, second, third, and fourth stimulation of TOF) in the N-TOF and C-TOF groups did not differ. Recoveries of PTC in the N-PTC and C-PTC groups followed similar time course. T1/control twitch height and TOF ratio (T4/T1) in the N-TOF group were higher than those in the C-TOF group 80-120 min and 100-120 min after administration of vecuronium, respectively. CONCLUSION: Nicorandil accelerates recovery of neuromuscular block caused by vecuronium.

Anesthesia, Inhalation↗
PubMed2001

Increased exocytosis of secretory granules in contrast to reduced serum hormone levels in pituitary adenomas of humans and rats treated with dopamine agonist.

The release of secretory granules outside the cells increased in frequency, in inverse proportion to the marked decrease in serum prolactin (PRL) levels in human prolactin-secreting adenomas (PRLomas) treated with bromocriptine (CB), a dopamine agonist. Rat pituitary adenomas induced by diethylstilbestrol also showed an increase in exocytosis of the granules despite a reduction in serum PRL levels after CB treatment. To elucidate this curious phenomenon, which is contrary to current general knowledge that serum hormone levels are sustained by the exocytosis of the secretory granules, we combined morphometric analysis with analyses using a cell fractionation technique and immunocytochemistry. The results indicated that the proteins in secretory granules consisted of 90% nonhormonal proteins and 10% PRL. CB treatment did not change the levels of the former, while the levels of the latter were markedly reduced. Immunocytochemistry, using a protein-A gold method, revealed that the secretory granules in rats treated with CB contained fewer PRL molecules than the controls. Serum PRL elevation caused by the exocytoses, estimated by counting the exocytotic granules, were markedly lower (less than 10%) in CB-treated rats than in the controls. It was suggested that, after CB treatment, the composition of secretory granules altered, or that nonhormonal constituents in the granules disintegrated more slowly, and that the granules became detectable at the site of release for a longer period. Consequently, although granules that appear ultrastructurally similar to those in untreated adenomas are observed to be more frequently released in treated adenomas, it seems that they no longer contribute to raising the serum PRL levels.

Adenoma↗
PubMed2001

c-MET expression in myofibroblasts: role in autocrine activation and prognostic significance in lung adenocarcinoma.

Hepatocyte growth factor (HGF) plays important roles in tumor development and progression. It is currently thought that the main action of HGF is of a paracrine nature: HGF produced by mesenchymal cells acts on epithelial cells that express its receptor c-MET. In this investigation, we explored the significance of c-MET expression in myofibroblasts, both in culture and in patients with lung adenocarcinoma. We first showed that human myofibroblasts derived from primary lung cancer expressed c-MET mRNA and protein by reverse transcription-polymerase chain reaction and Western blot analysis. Proliferation of myofibroblasts was stimulated in a dose-dependent manner by exogenously added recombinant human HGF whereas it was inhibited in a dose-dependent manner by neutralizing antibody to HGF. The addition of HGF in the culture medium stimulated tyrosine phosphorylation of c-MET. The c-MET protein was immunohistochemically detected in myofibroblasts in the invasive area of lung adenocarcinoma. Finally, the prognostic significance of c-MET expression in stromal myofibroblasts was explored in patients with small-sized lung adenocarcinomas. c-MET-positive myofibroblasts were observed in 69 of 131 cases (53%). A significant relationship between myofibroblast c-MET expression and shortened patient survival was observed in a whole cohort of patients including all pathological stages (two-sided P: = 0.0089 by log-rank test) and in patients with stage IA disease (two-sided P: = 0.0019 by log-rank test). These data suggest that the HGF/c-MET system constitutes an autocrine activation loop in cancer-stromal myofibroblasts. This autocrine system may play a role in invasion and metastasis of lung adenocarcinoma.

Adenocarcinoma↗
PubMed2001

Fluorescence bronchoscopy in the detection of preinvasive bronchial lesions in patients with sputum cytology suspicious or positive for malignancy.

BACKGROUND: A new strategy in the treatment of squamous cell carcinoma of the tracheobronchial tree is the detection and eradication of preinvasive bronchial lesions before they become invasive cancers. It is, however, difficult to detect preinvasive lesions by conventional white-light bronchoscopy alone. PURPOSE: we conducted a detailed investigation on the use of fluorescence bronchoscopy in the detection of preinvasive bronchial lesions in patients with sputum cytology suspicious or positive for malignancy. METHODS: 64 participants with sputum cytology suspicious or positive for malignancy were examined with both white light and fluorescence bronchoscopy (LIFE group). Earlier to this study, before fluorescence bronchoscopy became available in our institute, 48 participants having sputum cytology suspicious or positive for malignancy were examined with white light bronchoscopy alone (control group). Biopsy specimens for pathological examinations were taken of all abnormal areas discovered by white light or fluorescence bronchoscopy examination. RESULTS: In sputum cytology suspicious or positive for malignancy, the diagnosis of preinvasive bronchial lesions was greatly enhanced in the LIFE group as compared with the control group (45 vs. 7 lesions). The percentage of participants with preinvasive bronchial lesions was also significantly higher in the LIFE group than in the control group (40.6 vs. 12.5%, P = 0.00087, respectively). CONCLUSIONS: Our study suggests that the use of fluorescence bronchoscopy in addition to conventional white-light examination could greatly enhance the detection and localization of preinvasive bronchial lesions in patients with sputum cytology suspicious or positive for malignancy.

Aged↗
PubMed2001

The distribution of PIG-A gene abnormalities in paroxysmal nocturnal hemoglobinuria granulocytes and cultured erythroblasts.

Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired hemolytic anemia that is characterized by a deficiency of glycosylphosphatidylinositol-anchored membrane proteins due to phosphatidylinositol glycan-class A (PIG-A) gene abnormalities in various lineages of peripheral blood cells and hematopoietic precursors. The purpose of our study was to clarify the distribution of PIG-A gene abnormalities among various cell lineages during differentiation and maturation in PNH patients. The expression of CD16b or CD59 in peripheral blood granulocytes or cultured erythroblasts from three Japanese PNH patients was analyzed using flow cytometry. PIG-A gene abnormalities in both cell types, including glycophorin A(+) bone marrow erythroblasts, were examined using nucleotide sequence analysis. The expression study of PIG-A genes from each patient was also performed using JY-5 cells.Flow cytometry revealed that the erythroblasts consisted of negative, intermediate, and positive populations in Cases 1 and 3 and negative and intermediate populations in Case 2. The granulocytes consisted of negative and positive populations in all three cases. DNA sequence analysis indicated that all the PNH cases had two or three types of PIG-A gene abnormalities, and that a predominant clone with an abnormal PIG-A gene was different in granulocytes and erythroblasts from Cases 2 and 3. Expression studies showed that all the mutations from the patients were responsible for the null phenotype.PIG-A gene abnormalities result in deficiencies of glycosylphosphatidylinositol-anchored proteins in PNH erythroblasts and granulocytes. The distribution of predominant PNH clones with PIG-A gene abnormalities is often heterogeneous between the cell types, suggesting that a clonal selection of PIG-A gene abnormalities occurs independently among various cell lineages during differentiation and maturation.

Adult↗
PubMed2001

Characterization of premature atherosclerosis of carotid arteries in acromegalic patients.

OBJECTIVE: Acromegalic patients have increased mortality from vascular diseases. Although atherosclerotic risk factors such as hypertension, diabetes mellitus and dyslipoproteinaemia are highly associated with acromegaly, the prevalence of premature atherosclerosis in acromegalic patients and its relationship to these risk factors have not been reported. DESIGN: We measured mean intima-media thickness (IMT) of the carotid arteries in 21 acromegalic patients without symptomatic atherosclerotic vascular disease, by ultrasound high-resolution B-mode imaging. In analysis 1, it was compared with the predicted mean IMT based on data from existing risk factors (age, male sex, dyslipoproteinaemia, hypertension, diabetes mellitus, smoking status) in 282 non-acromegalic subjects. In analysis 2, the mean IMT in the 21 acromegalic patients was compared with that in 42 non-acromegalic subjects matched for age, sex and the other atherosclerotic risk factors. We also analysed clinical characteristics between the acromegalic patients with and without the atherosclerosis. RESULTS: Mean IMT in 21 acromegalic patients was 0.92 +/- 0.21 (mean +/- SD) mm. It was significantly (P < 0.05) lower than the mean IMT (1.03 +/- 0.12 mm) predicted from their existing risk factors (analysis 1). It was also less than that in 42 non-acromegalic subjects matched for atherosclerotic risk factors (1.07 +/- 0.37 mm; P < 0.05) (analysis 2). Among the acromegalic patients, 10 patients (48%) had increased mean IMT (> or = 1.1 mm) and/or plaque lesions whereas the other 11 had no such atherosclerotic changes. In the patients without the atherosclerotic changes, plasma insulin-like growth factor-I (IGF-I) concentration was significantly (P < 0.01) higher, and the prevalence of hypertension was significantly (P < 0.05) lower than in those with the atherosclerotic changes. CONCLUSIONS: The extent of carotid atherosclerosis in the acromegalic patients was not higher than that in non-acromegalic subjects, considering their atherosclerotic risk factors. Increased concentration of IGF-I might be involved in the lack of susceptibility to atherosclerosis in some acromegalic patients.

Acromegaly↗
PubMed2001

The effects of oral melatonin on the autonomic function in healthy subjects.

We investigated the influence of melatonin on the human autonomic functions by measuring muscle sympathetic nerve activity (MSNA). Five healthy male volunteers took 3 mg of melatonin, and their plasma melatonin concentration, blood pressure, heart rate, and burst rate of MSNA were then recorded. The peak level of melatonin concentration showed a marked interindividual variation. Blood pressure was reduced significantly, while heart rate and burst rate of MSNA did not change significantly. These results indicate that melatonin has a hypotensive effect on blood pressure, and the central cardiovascular regulatory mechanism such as lowering of the baroreflex setpoint would be involved in the effect.

Administration, Oral↗
PubMed2001

Multiple endocrine neoplasia type 2B.

We report a case of multiple endocrine neoplasia type 2B (MEN 2B) in a 30-year-old woman. There was no family history of MEN 2B in her family. DNA testing was carried out and a point mutation was found in exon 16, codon 918 (ATG to ACG) in the RET proto-oncogene. The woman died of medullary thyroid carcinoma, 13 years after a total thyroidectomy.

Adrenal Gland Neoplasms↗
PubMed2001

Prevalence and distinctive biologic features of flat colorectal adenomas in a North American population.

BACKGROUND & AIMS: To assess the prevalence of flat and depressed (F&D) colorectal adenomas in the United States, we performed a prospective study of 211 American patients. METHODS: Dye-assisted colonoscopy was performed in the presence of both an American and a Japanese investigator. RESULTS: F&D lesions were found in 22.7% of patients, and these were more likely to be adenomatous than polypoid lesions (82% vs. 67%; P = 0.03) and contained more invasive cancer (4.5% vs. 0%; P = 0.04), which also appeared to be at a disproportionately advanced stage. The average size of all F&D advanced lesions (high-grade dysplasia and cancer) was significantly smaller than comparable polypoid lesions (10.75 +/- 2.7 mm vs. 20 +/- 2.9 mm; P < 0.05). F&D adenomas showed significantly stronger fragile histidine triad (FHIT) expression and lower p53 reactivity than similarly sized polypoid adenomas, whereas proliferative and apoptotic indices were similar in both groups. CONCLUSIONS: We conclude that there is a significant prevalence of colonic F&D colorectal adenomas in this country and that these lesions have significantly different biologic features than polypoid lesions. The clinical and epidemiologic implications of these findings for American patients need to be addressed in further studies.

Acid Anhydride Hydrolases↗
PubMed2001

Laparoscopic extended cholecystectomy.

BACKGROUND: Inadvertent dissemination of latent gallbladder (GB) cancer has become a crucial issue with the widespread use of laparoscopic cholecystectomy as a standard operation for benign gallbladder diseases. METHODS: Laparoscopic extended cholecystectomy is a new technique we have developed for the resection of GB tumors with suspicion of malignancy. The procedure is safe and minimally invasive and prevents tumor dissemination. The GB is resected laparoscopically along with a 1-cm margin of the liver using LaparoSonic Coagulating Shears without any ligation or clipping. RESULTS: We applied this technique to a patient with a GB tumor in the fundus. The tumor was not exposed on the cut surface, and there were no postoperative complications. CONCLUSION: Laparoscopic extended cholecystectomy for GB tumors with suspicion of malignancy is a minimally invasive technique that may decrease the risk of tumor dissemination.

Cholecystectomy, Laparoscopic↗
PubMed2001

Infusion of amino acid enriched solution hastens recovery from neuromuscular block caused by vecuronium.

We investigated the effect of an amino acid infusion on neuromuscular block produced by vecuronium, and on rectal temperature and surface temperature over the adductor pollicis muscle. Sixty adult patients undergoing general anaesthesia were randomly divided into four groups of 15 patients each: amino acid (AA)-post-tetanic count (PTC); AA-train-of-four (TOF); control (C)-PTC; or C-TOF group. In the AA-PTC and AA-TOF groups, after a bolus of vecuronium 0.1 mg kg(-1), a continuous infusion of an 18 amino acid enriched solution (AMIPAREN) was started at a rate of 166 kJ h(-1). In the C-PTC and C-TOF groups, normal saline was administered. Time from vecuronium to the return of the PTC in the AA-PTC group was significantly shorter than in the C-PTC group (mean (SD), 13.3 (4.5) versus 18.0 (5.6) min, P<0.05). Times to return of T1, T2, T3, and T4 (first, second, third, and fourth twitch of TOF) in the AA-TOF group were significantly shorter than in the C-TOF group (21.1 (4.5) versus 28.0 (8.2) min for T1, P<0.05). PTC in the AA-PTC group was significantly greater than in the C-PTC group; 25-35 min after administration of vecuronium (P<0.05). T1/T0 and T4/T1 in the AA-TOF group were significantly higher than in the C-TOF group, 40-120 and 50-120 min after vecuronium respectively (P<0.05). Rectal temperature and surface temperature over the adductor pollicis muscle in the AA-PTC and AA-TOF groups were significantly higher than in the control groups 50-120 and 100-120 min after vecuronium respectively (P<0.05). Infusion of amino acid enriched solution hastens recovery from neuromuscular block.

Adult↗
PubMed2001

The anxiolytic effects of the 5-hydroxytryptamine-1A agonist tandospirone before otolaryngologic surgery.

UNLABELLED: We studied 160 ASA I or II patients undergoing elective otolaryngologic surgery in order to compare the anxiolytic effects of a novel 5-hydroxytryptamine-1A agonist, tandospirone, with diazepam. To monitor preoperative anxiety, the following variables were used: systolic and diastolic arterial pressure, heart rate, and the state anxiety score yielded by the Spielberger State-Trait Anxiety Inventory. We performed pretreatment evaluation on the day before surgery and posttreatment examination immediately after entry into the operating room. In a double-blinded, randomized design, four groups of 40 patients each received one of the following oral medications 90 min before entry into the operating room: 1) tandospirone 10 mg (T10 group); 2) tandospirone 30 mg (T30 group); 3) diazepam 10 mg (D group); or 4) placebo (P group). After premedication, the State-Trait Anxiety Inventory state anxiety decreased in the T10 (P < 0.02), T30 (P < 0.02), and D groups (P < 0.001), but it increased in the P group (P < 0.001). Tandospirone, 10 and 30 mg, safely reduced preoperative anxiety to a similar extent as oral diazepam 10 mg in patients undergoing elective otolaryngologic surgery. IMPLICATIONS: Oral tandospirone reduces preoperative anxiety to a similar extent as oral diazepam in patients undergoing elective otolaryngologic surgery. This finding implies that tandospirone can be used as an oral premedicant drug for relieving anxiety before surgery.

Adolescent↗
PubMed2001

Prevention of vomiting after tonsillectomy in children: granisetron versus ramosetron.

OBJECTIVE/HYPOTHESIS: Granisetron, a selective 5-hydroxytryptamine type 3 receptor antagonist, is effective for the prevention of vomiting after tonsillectomy in children. Ramosetron (Nasea; Yamanouchi; Tokyo, Japan), another new antagonist of 5-hydroxytryptamione type 3 receptor, has more potent and longer-acting properties than granisetron (Kytril; Smith Kline Beecham, London, UK) against cisplatin-induced emesis. This study was undertaken to compare the efficacy and safety of granisetron and ramosetron for the prevention of vomiting after pediatric tonsillectomy. STUDY DESIGN: Prospective, randomized, double-blinded study. METHODS: Ninety pediatric patients, aged 4 to 10 years, received intravenously granisetron 40 microg/kg or ramosetron 6 microg/kg (n = 45 each) at the end of surgery. The same standard general anesthetic technique and postoperative analgesia were used throughout. Emetic episodes and safety assessment were performed during the first 24-hour period and the next 24-hour period after anesthesia. RESULTS: The rates of patients being emesis-free during the period from 0 to 24 hours after anesthesia were 89% with granisetron and 93% with ramosetron, respectively (P = .357); the corresponding rates during the period from 24 to 48 hours after anesthesia were 71% and 93%, respectively (P = .006). No clinically serious adverse events attributable to the study drugs were observed in any of the groups. CONCLUSION: Ramosetron is a better antiemetic than granisetron for the long-term prevention of postoperative vomiting in children undergoing general anesthesia for tonsillectomy.

Antiemetics↗
PubMed2001

Differentiating between progressive supranuclear palsy and corticobasal degeneration by brain perfusion SPET.

The purpose of this study was to evaluate the usefulness of brain perfusion single photon emission computed tomography (SPET) to differentiate between progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD). Twelve patients with PSP and 12 with CBD were examined by brain perfusion SPET using 99Tc(m)-ethyl cysteinate dimer (99Tc(m)-ECD). The regions of interest (ROIs) were five cortical regions, the basal ganglia, the thalamus, the cerebellar cortex and the brain stem. The mean regional cerebral blood flow (CBF) and the mean right/left asymmetry index in each ROI were calculated. The asymmetry index of the regional CBF was significantly higher in CBD patients compared with PSP patients in all of the cortical regions and in the basal ganglia. The greatest differences in asymmetry were in the parietal cortex (P<0.001), high frontal cortex (P<0.001), frontal cortex (P<0.005), temporal cortex (P<0.01) and basal ganglia (P<0.01). Significant asymmetry was also detected in the occipital cortex (P < 0.05). No significant difference in asymmetry was found in the thalamus or the cerebellum. There were no significant differences between the two groups in any of the regional CBF values. In conclusion, brain perfusion SPET with 99Tc(m)-ECD is useful in detecting the significantly higher perfusion asymmetry in CBD patients compared with PSP patients in all cortical regions and in the basal ganglia. SPET may be a useful tool for differentiating between PSP and CBD.

Aged↗
PubMed2001

Reduced expression of syndecan-1 affects metastatic potential and clinical outcome in patients with colorectal cancer.

Syndecan-1 is a transmembrane heparansulfate proteoglycan which regulates cell-to-cell or cell-to-extracellular matrix interactions and may influence malignant cell behavior. We investigated the alterations of syndecan-1 expressions in colorectal cancers and analyzed the relationship between histological and clinical characteristics. Syndecan-1 protein expression in colorectal cancer tissues was investigated with immunohistochemical staining of resected specimens. In situ hybridization was performed using syndecan-1 riboprobe to confirm the transcriptional signals. Syndecan-1 mRNA expression in cancer cell lines cultured with or without methylation inhibitor was also analyzed by quantitative PCR. Out of 105 specimens tested, less than 25% of tumor cells were stained with anti-syndecan-1 monoclonal antibody in 36 (34.3%). In situ hybridization showed a similar staining profile to that of immunohistochemistry. Syndecan-1 mRNA expression was increased by the methylation inhibitor 5-aza-2'-deoxycytidine, suggesting that the hypermethylation is involved in the suppression of syndecan-1 expression. Clinically, the incidence of metastasis to lymphnode or liver in patients with syndecan-1-negative tumors was significantly high. Among T1 colorectal cancers displaying a primary invasive phase, lymphnode metastasis, undifferentiated characters and 'budding' of cancer cells were more common in syndecan-1-negative tumors. The survival rate in patients with syndecan-1-negative tumors was decreased significantly in a stage-independent manner. These results suggest that the reduction of syndecan-1 expression in colorectal cancer cells, which is supposed to be regulated at the transcription level, is closely related to invasive character. The evaluation of syndecan-1 expression in colorectal cancer may allow prediction of patients' survival after surgery.

Adenocarcinoma↗
PubMed2001

Dimer and superstructure of the active form of a vitamin D3; 1 alpha,24(R)dihydroxy-vitamin D3 monohydrate, C27O3H44.H2O.

The crystals of 1alpha24(R)dihydroxy-vitamin D3 monohydrate, C27O3H44.H2O are orthorhombic in the space group P2(1)2(1)2(1) with cell dimensions a=25.719, b=42.572, c=9.851A and Z=16. The asymmetric unit consists of two subunits with b/8, and each subunit contains a dimer in which two molecules are hydrogen-bonded through water molecules into non-crystallographical symmetry of C2. The two-fold axes are the straight lines, x=1/2, z=0.256 and x=1/2, z=0.623. The two dimers are the same in the rigid ring part, but differ in the conformation of the flexible chains. The dimers further make C2 symmetry between the rigid ring parts to form a superstructure, and the two-fold axis of the straight line, y=1/8, z=0.435 goes through a point that is a little apart from the hypercenter (1/2, 1/8, 1/2). The structure was solved by integrated Patterson and direct methods and refined on Fo2 under restraints. The final R1 is 0.228 on Fo for 1623 reflections with Fo>3sigma, resolutions 1.0-3.0 A, 313 restraints, 490 parameters and average Ueq=0.120. Not all the atoms of the chains appeared nor the hydrogen atoms. The missing atoms of the dimer were modeled from another pair molecule by C2 symmetry and hydrogen atoms were added. The structure of the dimer was optimized by ab initio molecular orbital of HF/6-31G.

Algorithms↗
PubMed2001

Surgeon's position for transsphenoidal surgery--technical note.

Transsphenoidal resection of pituitary tumors is usually performed with the surgeon standing on the patient's right side. However, this configuration is awkward when the tumor extends to the right and access may be hindered if the patient has poor nuchal flexibility or a large chest due to giantism or acromegaly. The surgeon stood on the left side of the patient during transsphenoidal surgery in five selected cases. The position on the left provided good access to the tumors with minimal changes in technique.

Cardiac Surgical Procedures↗