Search PubMed⌕ Search

Biomedical subjects

M Kudo

Publications and source records attributed to M Kudo.

At least 19 recordsLinked to original sources
PubMed2005

Approach for simultaneous measurement of two-dimensional angular distribution of charged particles: spherical aberration correction using an ellipsoidal mesh.

An approach for simultaneous measurement of two-dimensional angular distribution of charged particles is proposed. This concerns spherical aberration correction in electrostatic lenses with potential use of a mesh. In an earlier work, an effective use of a spherical mesh has succeeded to obtain a large acceptance angle limited to around 60 degrees (+/- 30 degrees). The present work is aimed at dramatically increasing acceptance angles limited in conventional lenses. For this purpose, spherical aberration behavior of mesh lenses is studied in detail using an analytical approximation and ray tracing, with particular attention paid to the effect of the mesh shape. It is shown here that the lens ability to correct spherical aberration over wide aperture angles can be effectively enhanced by the ellipsoidal deformation of a spherical mesh. We demonstrate that an effective use of an ellipsoidal mesh provides remarkable performance characteristics for electrostatic lenses, which opens new possibilities in surface and materials analysis techniques. Simple examples of ellipsoidal mesh lenses are presented that allow very wide acceptance angles of up to 120 degrees.

Journal Article↗
PubMed2005

Isoflurane increases norepinephrine release in the rat preoptic area and the posterior hypothalamus in vivo and in vitro: Relevance to thermoregulation during anesthesia.

General anesthetics modulate autonomic nervous system function including thermoregulatory control, which resides in the preoptic area of the anterior hypothalamus. However, the mechanism by which anesthetics modulate hypothalamic function remains unknown. We hypothesized that isoflurane increases norepinephrine release in the preoptic area and in the posterior hypothalamus causing hypothermia during anesthesia. To test this hypothesis, we performed a series of in vivo and in vitro studies in rats. In vivo studies: 1) Norepinephrine release was measured by microdialysis in the preoptic area or the posterior hypothalamus (n=9 each) before, during (30 min), and after (50 min) rats were anesthetized with 2% isoflurane. 2) In five rats, blood gases and arterial pressure were measured. 3) Body temperature changes (n=6 each) were measured after prazosin (0, 0.05, 0.5 microg), norepinephrine (0, 0.1, 1.0 microg), or 0.5 microg prazosin with 1.0 microg norepinephrine injection into the preoptic area. In vitro study: Norepinephrine release was measured from anterior or posterior hypothalamic slices (n=10 each) incubated with 0, 1, 2, or 4% isoflurane in Ca2+-containing buffer or with 4% isoflurane (n=10) in Ca2+-free buffer. Data were analyzed with repeated measures or factorial ANOVA and Student-Newman-Keuls tests. P<0.05 was significant. During anesthesia, norepinephrine release in the preoptic area was increased approximately 270%, whereas the release in the posterior hypothalamus remained unchanged. During emergence, posterior hypothalamic norepinephrine release increased by approximately 250% (P<0.05). Rectal temperature changes correlated with norepinephrine release from the preoptic area. Norepinephrine in the preoptic area enhanced isoflurane-induced hypothermia, while prazosin reversed it. Norepinephrine release from anterior hypothalamic slices increased at all isoflurane concentrations, but only at the highest concentration in posterior hypothalamic slices. Under Ca2+-free conditions, 4% isoflurane increased norepinephrine from both regions. These results suggest that augmentation of norepinephrine release in the preoptic area is responsible for hypothermia during general anesthesia.

Anesthesia↗
PubMed2005

Randomized, double-blind, placebo-controlled crossover trial of famotidine in patients with functional dyspepsia.

BACKGROUND: Histamine 2-receptor antagonists were used as a first therapy against functional dyspepsia. However, few clinical studies with famotidine for functional dyspepsia have been reported. AIM: To evaluate the effectiveness of famotidine for functional dyspepsia patients. METHODS: A multicentre, randomized, double-blind, placebo-controlled crossover trail was conducted. Patients diagnosed with functional dyspepsia by the Roma II criteria were included. Subjects were randomized into two groups, and received either famotidine or placebo as the first 4 weeks medication. After a 1-week washout period, they were switched to the other regimen for another 4 weeks. Evaluation was made prior to the start of study, upon completion of the first drug cycle, and the second drug cycle, by Gastrointestinal Symptoms Rating Scale for the seriousness of abdominal symptoms, and by Short Form-36 for the level of quality of life. RESULTS: Nineteen of 21 enrolled patients successfully completed this study. Significant improvement in Gastrointestinal Symptoms Rating Scale scores was observed in abdominal pain (P = 0.007), indigestion and reflux syndrome after famotidine treatment. Also quality of life scores showed significant improvement in body pain, vitality and general health perceptions after famotidine treatment. There was no improvement of symptoms and quality of life scores after administration of placebo. CONCLUSIONS: Famotidine was effective for improving symptoms and quality of life in functional dyspepsia patients.

Adult↗
PubMed2005

CagA in Barrett's oesophagus in Colombia, a country with a high prevalence of gastric cancer.

BACKGROUND: In the USA, atrophic gastritis and gastric cancer are rare, whereas gastro-oesophageal reflux disease (GERD) is common. Infection with Helicobacter pylori, especially a CagA positive strain, is unusual in patients with GERD/Barrett's oesophagus in the USA. AIM: To examine the relation between Barrett's oesophagus and CagA positive H pylori in Colombia, a country with a high prevalence of CagA positive H pylori associated atrophic gastritis and gastric cancer. METHODS: Helicobacter pylori and CagA status was determined among Colombian patients with long segment Barrett's oesophagus and a control group with simple H pylori gastritis. Helicobacter pylori status was determined using a triple stain and CagA status was determined by immunohistochemistry using a specific rabbit anti-CagA serum. RESULTS: Gastric and oesophageal mucosal biopsies were obtained from 51 patients--39 men (mean age, 57.8 years; SD, 13.1) and 12 women (mean age, 51.8 years; SD, 14.4)--with documented long segment Barrett's oesophagus. The results were compared with 24 Colombian patients with H pylori gastritis without oesophageal disease. Thirty two patients with Barrett's oesophagus had active H pylori infection. CagA status was evaluated in a subset of 23 H pylori infected patients with Barrett's oesophagus, and was positive in eight of these patients compared with 19 of 24 controls (p = 0.01). CONCLUSIONS: Although most Colombian patients with Barrett's oesophagus had H pylori infection, CagA positive infections were unusual. These data illustrate how consistent corpus inflammation reduces acid secretion, which prevents Barrett's oesophagus among those with abnormal gastro-oesophageal reflux barriers.

Adult↗
PubMed2005

Hepatic angiomyolipoma: identification of an efferent vessel to be hepatic vein by contrast-enhanced harmonic ultrasound.

We report two patients with rare hepatic angiomyolipoma and demonstrate the special tumour haemodynamics with contrast-enhanced harmonic ultrasound. This reliably identified the efferent vessel of the hepatic angiomyolipoma to be the hepatic vein in both cases, which corresponded well with that seen on conventional angiography and CT angiography. This haemodynamic finding may be an important characteristic of hepatic angiomyolipoma, and facilitate the differential diagnosis from other benign and malignant hepatic tumours.

Angiomyolipoma↗
PubMed2005

Implication of the peak serum level of mizoribine for control of the serum anti-dsDNA antibody titer in patients with lupus nephritis.

AIM: Mizoribine (MZR) is a novel selective inhibitor of inosine monophosphatase dehydrogenase that was developed in Japan. We previously reported the efficacy and safety of oral MZR pulse therapy, which is associated with elevated peak serum MZR levels, in selected patients with lupus nephritis. However, only limited information is available as yet on the optimal peak serum level of MZR that would yield an enhanced clinical efficacy without serious toxicity in patients with lupus nephritis. METHODS: A total of 11 patients with clinically stable lupus nephritis treated with oral MZR pulse therapy combined with low-dose prednisolone were enrolled in the cross-sectional study. The peak serum concentrations of MZR (as determined by HPLC) and the serum anti-dsDNA antibody titers (as determined by ELISA) were examined in the patients in order to evaluate the correlation between these two parameters. The correlation between the dose of MZR (mg/kg) administered orally as a single daily dose and the peak serum level of the drug was also examined. In two of the patients, serial measurements of the changes in the peak serum levels of MZR and anti-dsDNA titers could be conducted over 10 months. RESULTS: A significant inverse correlation (r = -0.596, p = 0.0116) was observed between the peak serum levels of MZR and the serum anti-dsDNA antibody titers in the study participants, while the dose of prednisolone remained unchanged. The peak level of MZR in the serum was significantly correlated with the single dose of MZR (r = 0.509, p = 0.0371). In the two patients in whom serial measurements were conducted, the first patient who showed a peak serum MZR level of less than 2.5-3.0 microg/ml eventually developed an increase of the serum anti-dsDNA titer with hypocomplementemia and proteinuria. On the other hand, in the second patient who showed a peak serum MZR level in excess of 4.0 microg/ml, persistently low serum anti-dsDNA titers with normocomplementemia were observed. CONCLUSION: Although this study is only a preliminary study conducted on a small sample, we speculate from the results that a peak serum level of MZR of at least more than 2.5-3.0 mirog/ml is necessary to achieve satisfactory clinical efficacy of the drug for the treatment of lupus nephritis. Further study is needed to confirm these preliminary findings.

Administration, Oral↗
PubMed2005

C1-C2 point monitoring of low-dose cyclosporin a given as a single daily dose in children with steroid-dependent relapsing nephrotic syndrome.

AIM: It has been reported that the pharmacokinetics of cyclosporin A (CsA) in children is different from that in adults. It appears that, in general, pediatric patients metabolize CsA more rapidly than adult patients, necessitating the use of higher dose of the drug in pediatric transplant recipients. In this context, we speculated that single-dose daily administration of low-dose CsA may be associated with a higher peak blood level without associated trough blood level elevation, and thereby yield better results and allow safer use of the drug than the conventional twice daily administration dosing used for the treatment of childhood idiopathic nephrotic syndrome (INS). METHODS: A total of 10 children with steroid-dependent relapsing INS (9 with biopsy-proven minimal-change disease) who showed steroid toxicity were enrolled in the study. The initial daily dose of CsA (Neoral) used was around 2.0 mg/kg, given as a single daily dose before breakfast. The dose was subsequently adjusted to achieve a C1-C2 point blood level between 600 - 800 ng/ml. The dose of the concomitantly administered prednisolone was tapered following the commencement of CsA. RESULTS: The mean daily CsA dosage, the mean C1-C2 point blood level and the mean trough blood level in the subjects were 2.2 +/- 0.8 mg/kg, 754.0 +/- 71.9 ng/ml and 42.7 +/- 29.2 ng/ml, respectively. At the latest observation, after a mean duration of 17 months (6 - 24 months) of CsA therapy, the minimum dose of prednisolone required for maintenance of clinical remission and the calculated relapse rate were significantly decreased as compared to the respective pretreatment values (0.52 +/- 0.46 mg/kg on alternate days, vs. 0.97 +/- 0.63 mg/kg on alternate days, and 0.28 +/- 0.32 times per six months, vs. 1.06 +/- 0.41 times per six months, respectively, p = 0.005). No significant change was observed in the mean estimated GFR value as compared to the pretreatment value (183.1 +/- 35.4 ml/min/1.73 m2vs. 185.4 +/- 39.3 ml/min/1.73 m2). No evidence of CsA nephrotoxicity was observed in a repeat renal biopsy performed around 12 months after the commencement of CsA therapy in two patients. CONCLUSIONS: Despite the limitations of the study, our results suggest that administration of low-dose CsA as a single daily dose with C1-C2 point blood level monitoring might be an equally effective and safe and, therefore, more cost-beneficial, protocol for the treatment of steroid-dependent cases of relapsing INS, as conventional twice-daily administration of CsA with trough blood level monitoring. Further studies to confirm the long-term efficacy and safety of this CsA treatment protocol in larger numbers of patients are, however, needed.

Adolescent↗
PubMed2005

[Successful treatment of bronchial mucoepidermoid carcinoma by bronchoplasty].

A 63-year-old man who was pointed out abnormal shadow on chest X-ray admitted to our hospital. Chest computed tomography (CT) showed a tumor originated from right upper bronchus and grew into right main bronchus. The tumor was diagnosed as mucoepidermoid carcinoma by bronchoscopic biopsy. Fluorodeoxyglucose positron emission tomography (FDG-PET) showed abnormal uptake localized at the tumor. The standardized uptake values of the tumor 60 minutes after injection were 2.86, and 120 minutes after injection, it increased to 3.97. Right upper lobectomy with bronchoplasty by deep wedge resection of right main bronchus at the orifice of right upper bronchus and lymphadenectomy was performed. Pathological diagnosis was high-grade mucoepidermoid carcinoma without lymph nodes metastasis which was compatible with FDG-PET. Postoperative course was uneventful.

Bronchi↗
PubMed2005

[Minimal invasive cardiac surgery using port-access method in elderly patients].

Cardiac surgery in elderly patients are increasing in recent years. From October 1997 to December 2004, we operated on 163 patients with port-access cardiac surgery, of whom 5 were over 70 years old (elderly group) and 158 were 16-69 years old (young group). The patients were 91 with atrial septal defect (ASD), 64 with mitral valve disease, 2 with coronary artery disease (coronary artery bypass grafting : CABG), and 10 with other (ventricular septal defect : VSD, myxoma et al.). This report presents result of port-access cardiac surgery in elderly patients. No significant difference was found between 2 groups in extracorporeal time, aortic clamp time, postoperative intubation period and postoperative hospital stay. However, the transfusion rate in mitral valve lesion were higher in elderly patient (100%) than in younger ones (18%). In conclusion, it seems that port-access cardiac surgery was to be a useful for elderly patient though contraindications were accepted such as peripheral arteriosclerosis and calcification of aorta.

Adolescent↗
PubMed2004

Performance of bispectral index and auditory evoked potential monitors in detecting loss of consciousness during anaesthetic induction with propofol with and without fentanyl.

BACKGROUND AND OBJECTIVE: To investigate and compare the performance of bispectral index (BIS) and auditory evoked response index (AAI) in detecting the transition from consciousness to unconsciousness during anaesthesia induction by propofol, alone and in combination with fentanyl. METHODS: Anaesthesia was induced with either an intravenous infusion of 30 mg kg(-1)h(-1) of propofol plus 2 microg kg(-1) of fentanyl (Group PF, n = 20) or an intravenous infusion of 30 mg kg(-1) h(-1) of propofol plus normal saline (Group P, n = 20). BIS, AAI and the doses of propofol administered were recorded at the end-point of unresponsiveness to verbal commands. The propofol plasma concentration was also measured. RESULTS: The propofol dose and plasma propofol concentration required to achieve loss of consciousness were significantly lower in patients pretreated with fentanyl (P < 0.001). The mean BIS value at loss of consciousness was significantly different between the two groups (74.10 in Group PF vs. 60.80 in Group P) (P < 0.001). However, no difference in the AAI was seen between the two groups at loss of consciousness (32.90 in Group PF vs. 31.80 in Group P) (P > 0.05). In both groups, the regression analysis values (r-values) between BIS and plasma propofol concentrations at the onset of unconsciousness were higher than those between AAI and propofol concentrations (0.553 vs. 0.180 in Group P; 0.432 vs. 0.308 in Group PF). CONCLUSIONS: These results show that a fentanyl bolus is effective in augmenting the hypnotic effect of propofol during anaesthesia induction. AAI appears to be able to measure the transition from consciousness to unconsciousness at similar values, regardless of whether or not fentanyl pretreatment is used whereas the BIS values were not independent of fentanyl pretreatment. This suggests that AAI may be a better indicator of conscious status during propofol/fentanyl anaesthesia, where it appears to be independent of the anaesthesia regimen.

Adolescent↗
PubMed2004

Closed continuous hyperthermic peritoneal perfusion model in mice with peritoneal dissemination of colon 26.

An original model of closed continuous hyperthermic peritoneal perfusion (CHPP) in mice is presented and was found to support the efficacy of intraperitoneal hyperthermia. Closed CHPP was performed after intraperitoneal inoculation of transplantable colon 26 cells into a mouse. Colon 26 cells (5 x 10(4)) were injected into 18 mice. The mice were then allocated to six groups of three each and subjected to peritoneal perfusion over time. Peritoneal washings from each mouse were sampled and counted by the cytosmear method. On day 10 after inoculation, colonies of the disseminated tumour were seen on the mesentery by staining with 0.1% methylene blue for 5 min. The number of tumour nodules on the mesentery was counted. The number of washed-out tumour cells decreased the most at 24 h after inoculation, and 76% of the inoculated cells did not wash out during the peritoneal perfusion procedure. CHPP was performed after 24 h when colon 26 cells were injected into the peritoneal cavity because this status may represent micrometastasis. The total number of nodules on the mesentery in the CHPP group was significantly smaller than that in the control (p < 0.02). In conclusion, because this treatment model is similar to the clinical CHPP, the biostaining model might be useful for the evaluation of peritoneal dissemination and it was unique and valuable in demonstrating an effective treatment for the prevention of peritoneal dissemination.

Animals↗
PubMed2004

Dynamic imaging of pancreatic diseases by contrast enhanced coded phase inversion harmonic ultrasonography.

BACKGROUND: Coded phase inversion harmonic ultrasonography, a newly available sonographic technique, enables visualisation of slow flow in minute vessels in a real time fashion with the use of a sonographic contrast agent containing monosaccharide. Our purpose was to employ this novel technique to observe microvessels in pancreatic tumours. SUBJECTS AND METHODS: Sixty five patients with suspicious pancreatic tumours received contrast enhanced coded phase inversion harmonic ultrasonography, contrast enhanced computed tomography, and endosonography. Final diagnoses based on histological findings were pancreatic ductal carcinomas in 49 patients, inflammatory pseudotumours with chronic pancreatitis in seven, and endocrine tumours in nine. For contrast enhanced coded harmonic ultrasonography, Levovist, a contrast agent, was injected intravenously as a bolus. When the first microbubble signal appeared in the pancreas, images of the ideal scanning plane were displayed in a real time continuous fashion (vessel images). Subsequently, interval delay scanning (perfusion images) was taken to demonstrate parenchymal flow. Tumour vascularity was evaluated by using the two types of imaging. Sensitivities for depicting pancreatic tumours were compared between three examinations. RESULTS: Contrast enhanced ultrasonography demonstrated tumour vessels in 67% of pancreatic ductal carcinomas, although most were relatively hypovascular compared with the surrounding pancreatic tissue. The vascular patterns of tumours obtained by contrast enhanced ultrasonography were closely correlated with those obtained by contrast enhanced computed tomography. Values for sensitivity in depicting pancreatic tumours of 2 cm or less in size were 68% for contrast enhanced computed tomography, 95% for endosonography, and 95% for contrast enhanced ultrasonography. CONCLUSION: Contrast enhanced coded phase inversion harmonic ultrasonography successfully visualised fine vessels in pancreatic tumours and may play a pivotal role in the depiction and differential diagnosis of pancreatic tumours.

Adult↗
PubMed2003

Orexinergic neurons and barbiturate anesthesia.

Orexins (OXs) regulate sleep with possible interactions with brain noradrenergic neurons. In addition, noradrenergic activity affects barbiturate anesthesia. As we have also recently reported that OXs selectively evoke norepinephrine release from rat cerebrocortical slices we hypothesized that barbiturate anesthesia may result from of an interaction with central orexinergic systems. To test this hypothesis, we performed a series of in vivo and in vitro studies in rats. In vivo, the effects of i.c.v. OX A, B and SB-334867-A (OX1 receptor antagonist) on pentobarbital, thiopental or phenobarbital-induced anesthesia times (loss of righting reflex) was assessed. In vitro effects of barbiturates and SB-334867-A on OX-evoked norepinephrine release from cerebrocortical slice was examined. In Chinese hamster ovary cells expressing human OX1/OX2 receptors OX A- and B-evoked increases in intracellular Ca2+ were measured with and without barbiturates. OX A and B significantly decreased pentobarbital, thiopental and phenobarbital anesthesia times by 15-40%. SB-334867-A increased thiopental-induced anesthesia time by approximately by 40%, and reversed the decrease produced by OX A. In vitro, all anesthetic barbiturates inhibited OX-evoked norepinephrine release with clinically relevant IC50 values. A GABAA antagonist, bicuculline, did not modify the inhibitory effects of thiopental and the GABAA agonist, muscimol, did not inhibit norepinephrine release. In addition there was no interaction of barbiturates with either OX1 or OX2 receptors. Collectively our data suggest that orexinergic neurons may be an important target for barbiturates, and GABAA, OX1 and OX2 receptors may not be involved in this interaction.

Animals↗
PubMed2003

Long-term treatment with sterigmatocystin, a fungus toxin, enhances the development of intestinal metaplasia of gastric mucosa in Helicobacter pylori-infected Mongolian gerbils.

BACKGROUND: Helicobacter pylori is a human gastric carcinogen. Sterigmatocystin (ST), a fungus toxin, is a risk factor of gastric cancer. Cytotoxin-vacuolation toxin A (VacA) present in supernatants of H. pylori suspensions can cause gastritis and ulcer. The aim of this study was to examine the effects of H. pylori, ST and VacA in Mongolian gerbils. METHODS: Male Mongolian gerbils (n = 196) were treated with H. pylori supernatants (10 ml/1000 mg) mixed with diet or inoculated intragastrically with H. pylori alone or with ST (100 or 1000 ppb), and then killed 27 months later. Gastric tissue sections were stained with haematoxylin and eosin (H&E), periodic acid-Schiff (PAS), Alcian blue (AB, pH 2.5) and with immunostaining for PCNA and p53 expression. RESULTS: In H. pylori-infected gerbils, the normal mucosa was replaced by hyperplastic epithelium. Severe gastritis, cystic dilatation of gastric glands, hyperplastic polyps and intestinal metaplasia were observed. In H. pylori + ST (1000 ppb) gerbils, intestinal metaplasia was significantly more frequent than in H. pylori alone animals. No pathological changes were observed in the H. pylori supernatant group. Osseous metaplasia was observed in the H. pylori + ST (100 ppb) group. Serum gastrin levels of the H. pylori + ST (1000 ppb) group were significantly higher than those of the other groups. PCNA labelling index and p53 index of infected gerbils were significantly higher than those of uninfected groups. CONCLUSION: H. pylori causes gastritis, ulcer and intestinal metaplasia. ST enhances the development of intestinal metaplasia and increases gastrin levels in H. pylori-infected Mongolian gerbils.

Animals↗
PubMed2001

A stereoselective synthesis of the C10-C31 (BCDEF ring) portion of pinnatoxin A.

[reaction: see text] An efficient synthesis of the C10-C31 (BCDEF ring) portion of pinnatoxin A has been achieved. The key step is a highly stereoselective construction of the dispiroketal (BCD ring) system employing an intramolecular hetero-Michael reaction of a reversibly formed hemiketal alkoxide through the use of LiOMe.

Alkaloids↗
PubMed2001

Effects of nociceptinNH2 and [Nphe1]nociceptin(1-13)NH2 on rat brain noradrenaline release in vivo and in vitro.

We have investigated the effects of nociceptin/orphanin FQ (NC) receptor agonist NCNH2 and a competitive NC receptor antagonist, [Nphe1]NC(1-13)NH2 on noradrenaline (NA) release in vivo using microdialysis in freely moving animals and in vitro from cerebrocortical slices. One nmol of NCNH2 injected into rat locus coeruleus inhibited NA release from the prefrontal cortex (E(max) 27.4+/-5.7% 30 min after injection) which was partially (33%) reversed by 100 nmol of [Nphe1]NC(1-13)NH2. In cerebrocortical slices NCNH2 inhibited NA release in a concentration-dependent manner (EC50 12 nM, E(max) 29.4%) that was reversed by [Nphe1]NC(1-13)NH2. In both preparations, [Nphe1]NC(1-13)NH2 per se was inactive. These data demonstrate an inhibition of NA release by NCNH2 in a [Nphe1]NC(1-13)NH2 sensitive manner in both in vivo brain microdialysis and in vitro cerebrocortical slices studies in rats.

Animals↗