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Biomedical subjects

S Ikeda

Publications and source records attributed to S Ikeda.

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

Evaluation of persistence of ductus venosus with tc-99m DTPA galactosyl human serum albumin liver scintigraphy and I-123 iodoamphetamine per-rectal portal scintigraphy.

Tc-99m DTPA galactosyl human serum albumin (Tc-99m GSA) hepatic scintigraphy was performed in two patients with patent ductus venosus before and after operation. To evaluate the portosystemic shunt flow, per-rectal portal scintigraphy with I-123 N-isopropyl-p-iodoamphetamine (IMP) was undergone in the same period. The portosystemic shunt indices (PSS index) were decreased from 67.9% to 7.3% in the patient 1, and from 77.3% to 22.7% in the patient 2, respectively. Quantitative indices of Tc-99m GSA hepatic scintigraphy improved dramatically in both patients. Under microscopic examination, nearly all the hepatic cells showed signs of severe fatty degeneration. After the operation, the severe fatty degeneration was alleviated and all the hepatic cells appeared normal. I-123 IMP per-rectal portal scintigraphy and Tc-99m GSA hepatic scintigraphy were useful in evaluating the quantitative shunt flow of the persistent ductus venosus and its hepatic functional reserve.

Amphetamines↗
PubMed2000

Correlation between the expression of methionine adenosyltransferase and the stages of human colorectal carcinoma.

Methionine adenosyltransferase (MAT) catalyzes the synthesis of S-adenosylmethionine (AdoMet) from ATP and L-methionine. AdoMet is the major methyl donor in most transmethylation reactions in vivo, and it is also the propylamino donor in the biosynthesis of polyamines. In the present study, we assessed MAT activity in human colons with colorectal carcinoma and the values were compared with those of morphologically normal adjacent mucosa. Higher levels of MAT activity were observed in the colorectal carcinoma than in the normal colon. The ratio of MAT activity in tumor tissue versus normal tissue seemed to be correlated well will the stage of the colorectal tumor. Furthermore, immunoblot analysis showed that the high levels of MAT activity observed in colorectal carcinoma were due to the increased amounts of MAT protein. Immunohistochemical analysis revealed that MAT was most abundant in goblet cells, particularly in granules in the supranuclear area of these cells. In the colorectal carcinoma tissues, MAT was strongly stained in the cancerous cells and localized in granules in the supranuclear region. The results of this preliminary study suggest that determination of the relative ratio of MAT activity in both normal and tumor regions in human colorectal carcinoma could be a clinically useful tool for determining the stage of malignancy of colorectal carcinomas.

Adenocarcinoma↗
PubMed2000

Manganese deposits in patients with biliary atresia after hepatic porto-enterostomy.

PURPOSE: The aim of this study was to determine if there is latent manganese toxicity in patients with biliary atresia. METHODS: Fifteen children with biliary atresia were examined postoperatively with regard to whole-blood manganese levels using brain magnetic resonance imaging (MRI) and I-123 iodoamphetamine (IMP) per rectal portal scintigraphy. RESULTS: Nine (60%) of the 15 had high whole-blood manganese levels (mean, 4.1 microg/dL; range, 1.2 to 9.6; normal, 0.5 to 2.5), and these 9 had hyperintense globus pallidus on T1-weighted images, with no corresponding signal change in T2 sequences. I-123 IMP per rectal portal scintigraphy was done for 13 patients to evaluate portosystemic shunt flow. 12 (92%) of these patients had an increased flow. Mean shunt ratio was estimated to be 41% (range, 0.6 to 98; normal, <5%). Encephalopathy was evident in only 1 patient. CONCLUSIONS: Some patients with biliary atresia in the postoperative period have manganese deposits in globus pallidus on T1-weighted images and high whole-blood manganese levels, possibly caused by increased portsystemic shunt, and a latent or subclinical encephalopathy is also present.

Adolescent↗
PubMed2000

Assessment of human health risk of dioxins in Japan.

The human health risk of dioxins was evaluated for four Japanese receptor groups: the general population, local residents living near a municipal solid waste incinerator, heavy fish consumers, and their infants and fetuses. In describing the risk for these groups, four endpoints, namely, cancer, reproductive dysfunction, endometriosis and neurobehavioral effect, were considered, and the incremental cancer risk and margin of exposure (MOE) corresponding to these endpoints were calculated, based on three measures of dosimetry; average daily intake, area under the curve, and body burden. The uncertainties of these risk descriptors were also evaluated by probabilistic analysis. Although the estimated risk of cancer and reproductive dysfunction were not exceptionally high in the three adult receptor groups, the MOE values for endometriosis were not sufficiently high to guarantee safety against this endpoint. Furthermore, the MOE values for neurobehavioral effects on infants and fetuses suggest that dioxins may cause a considerable risk to those of local residents and heavy fish consumers.

Adult↗
PubMed2000

Independent component analysis for noisy data--MEG data analysis.

Independent component analysis (ICA) is a new, simple and powerful idea for analyzing multi-variant data. One of the successful applications is neurobiological data analysis such as electroencephalography (EEG), magnetic resonance imaging (MRI), and magnetoencephalography (MEG). However, many problems remain. In most cases, neurobiological data contain a lot of sensor noise, and the number of independent components is unknown. In this article, we discuss an approach to separate noise-contaminated data without knowing the number of independent components. A well-known two stage approach to ICA is to pre-process the data by principal component analysis (PCA), and then the necessary rotation matrix is estimated. Since PCA does not work well for noisy data, we implement a factor analysis model for pre-processing. In the new pre-processing, the number of sources and the amount of sensor noise are estimated. After the preprocessing, the rotation matrix is estimated using an ICA method. Through the experiments with MEG data, we show this approach is effective.

Artifacts↗
PubMed2000

Supplemental glutamine augments phagocytosis and reactive oxygen intermediate production by neutrophils and monocytes from postoperative patients in vitro.

The energy substrate for neutrophils has been believed to be glucose. However, a recent investigation has demonstrated that neutrophils use glutamine (Gln) as well as glucose. Nevertheless, little is known about the effects of Gln on neutrophil function. Thus, this study was designed to investigate the effects of Gln on phagocytosis and reactive oxygen intermediate (ROI) production by neutrophils from postoperative patients in vitro. Eleven patients who had undergone major gastrointestinal surgery were randomly selected. Peripheral blood was drawn before surgery and on postoperative days (PODs) 1, 3, and 7. The blood was washed with medium to remove plasma. Washed whole blood was incubated in RPMI 1640 medium containing neither Gln nor glucose for 24 h at 37 degrees C. The medium was supplemented with Gln at a concentration of 0, 500, 1000, or 2000 microM. Whole blood was then assessed for phagocytosis by flow cytometry using fluorescent beads. ROI production by phagocytes was measured by flow cytometry using dihydrorhodamine 123. In each assay, the neutrophil population was gated and analyzed. Serum amino acids were also measured. Postoperative serum Gln level decreased significantly until POD 7. Phagocytosis by neutrophils on PODs 3 and 7 was significantly greater at 2000 microM Gln than at other Gln concentrations. Neutrophil ROI production was significantly greater at 2000 microM Gln than at 0 microM Gln at each time point. In conclusion, supplemental Gln enhances both phagocytosis and ROI production by neutrophils from postoperative patients in vitro.

Aged↗
PubMed2000

Nickel-catalyzed intermolecular domino reactions.

Nickel-catalyzed multiple-component reactions are a promising new type of domino reaction. For instance, a variety of starting materials such as alkenes, alkynes, and unsaturated carbonyl compounds can be connected with high selectivity under reasonably mild conditions. These reactions provide a new route to synthetically important key compounds including dienes, enynes, enol silyl ethers, and carbocycles. Furthermore, an asymmetric version of the reaction is successful. Thus, intermolecular domino reactions should be important reactions for years to come.

Catalysis↗
PubMed2000

Intermolecular forces in bovine serum albumin solutions exhibiting solidlike mechanical behaviors.

Mechanical properties of bovine serum albumin (BSA) solutions were analyzed to gain information on intermolecular forces that stabilize the system under normal physiological conditions. BSA solutions showed unexpectedly large zero shear viscosity values under steady shear flows but responded like solids to sinusoidal linear strains: the storage shear moduli were always larger than the loss shear moduli in the frequency range 1-100 rad/s. These results suggest that BSA solutions are so-called colloidal crystals in which colloidal particles are ordered in an array due to strong repulsive forces among particles. However, the pair potential between BSA molecules predicted based on the conventional Derjaguin-Landau-Verwey-Overbeek theory failed to explain these remarkable mechanical properties of BSA solutions. Additional repulsive forces other than electrostatic must be introduced to explain stability of BSA aqueous dispersions.

Algorithms↗
PubMed2000

Phospholipid/fatty acid-induced secondary structural change in beta-lactoglobulin during heat-induced gelation.

Effects of phosphatidylcholine (PC) and the predominant fatty acids (FAs) in milk, butyrate, oleate, and palmitate, on secondary structural changes in beta-lactoglobulin (beta-LG) during heat-induced gelation were analyzed on the basis of circular dichroism (CD) spectra. Small-strain oscillatory measurements were carried out to characterize viscoelastic properties of the heat-induced gels. In the absence of added salt, PC and FAs induced helix formation of beta-LG on heating to 80 degrees C and increased the storage moduli (G') of heat-induced gels. In the presence of 500 mM NaCl, PC did not change the CD spectrum of beta-LG but decreased G'. In contrast, butyrate substantially unfolded beta-LG in 500 mM NaCl on heating, forming very elastic gels with increased G' values. Palmitate and oleate induced beta-LG gel formation at 25 degrees C without heating; heating to 80 degrees C almost completely unfolded beta-LG in 500 mM NaCl.

Fatty Acids↗
PubMed2000

Mutations in ATP2C1, encoding a calcium pump, cause Hailey-Hailey disease.

Hailey-Hailey disease (HHD, MIM 16960) is inherited in an autosomal dominant manner and characterized by persistent blisters and erosions of the skin. Impaired intercellular adhesion and epidermal blistering also occur in individuals with pemphigus (which is due to autoantibodies directed against desmosomal proteins) and in patients with Darier disease (DD, MIM 124200), which is caused by mutations in a gene encoding a sarco/endoplasmic reticulum (ER)-Golgi calcium pump. We report here the identification of mutations in ATP2C1, encoding the human homologue of an ATP-powered pump that sequesters calcium into the Golgi in yeast, in 21 HHD kindreds. Regulation of cytoplasmic calcium is impaired in cultured keratinocytes from HHD patients, and the normal epidermal calcium gradient is attenuated in vivo in HHD patients. Our findings not only provide an understanding of the molecular basis of HHD, but also underscore the importance of calcium control to the functioning of stratified squamous epithelia.

Adult↗
PubMed2000

Recurrent R156H mutation of KRT10 in a Japanese family with bullous congenital ichthyosiform erythroderma.

Recently, mutations of keratin 1 gene (KRT1) and keratin 10 gene (KRT10) have been reported in various patients with bullous congenital ichthyosiform erythroderma (BCIE). The substitution of arginine (R) to histidine (H) at amino acid residue 156 (R156H) of coiled 1A region is one of the most frequent mutations of KRT10. In this study, we searched for a mutation in KRT1 and KRT10 in a Japanese family with BCIE and detected mutation R156H in KRT10. Our search led to the detection of R156H. This mutation was not detected in 50 normal individuals. These results confirmed that codon 156 is a frequently mutated site, and that R156H in KRT10 is likely also to be a mutation hotspot in Japanese patients with BCIE.

Amino Acid Substitution↗
PubMed2000

Radiation retards muscle differentiation but does not affect osteoblastic differentiation induced by bone morphogenetic protein-2 in C2C12 myoblasts.

PURPOSE: Effects of radiation on the differentiation of C2C12 myoblasts were studied using cell cultures in which the cells differentiated into either muscle cells or osteoblasts. MATERIALS AND METHODS: A mouse skeletal myoblast cell line, C2C12, was cultured and irradiated at confluence. Muscle differentiation was estimated by counting the number of myosin heavy chain (MHC)-positive multinucleated myotubes. Osteoblast differentiation was analysed by measuring alkaline phosphatase (ALP) activity and osteocalcin production in C2C12 cells treated with recombinant human bone morphogenetic protein-2 (rhBMP-2). RESULTS: Myotube formation in C2C12 cells was inhibited by 2 and 4 Gy irradiation, but recovered to non-irradiated control levels following further culture. In irradiated cultures, the number of MHC-positive mononucleated cells increased significantly. Irradiation did not, however, alter the induction of osteoblastic phenotypes induced by rhBMP-2 in C2C12. Irradiation also did not affect the expression of MyoD mRNA and myogenin mRNA in myogenic differentiation and induction of osteocalcin mRNA in osteoblastic differentiation. CONCLUSIONS: During differentiation of C2C12 cells, myotube formation was delayed after irradiation, while induction of osteoblasts with BMP-2 was unaffected.

Alkaline Phosphatase↗
PubMed2000

Effects of midkine during in vitro maturation of bovine oocytes on subsequent developmental competence.

Midkine (MK) is known to be a member of a new family of heparin-binding growth/differentiation factors, together with pleiotrophin, and to be quite rich in bovine follicular fluid. To examine whether treatment with MK during in vitro maturation (IVM) of bovine granulosa-enclosed oocytes affects their nuclear maturation and postfertilization development to the blastocyst stage, bovine granulosa-enclosed oocytes obtained from slaughterhouse-derived ovaries were cultured for 24 h in IVM medium without (control) or with various concentrations (1-500 ng/ml) of MK, followed by in vitro fertilization (IVF) and culturing. Although the MK treatment during IVM did not affect the rate of nuclear maturation or the postfertilization cleavage of oocytes, MK at > or = 10 ng/ml significantly (P: < 0.05) increased the blastocyst yields per tested and per cleaved oocyte compared with the case of the control. Next, the effects of various glycosaminoglycans (heparin, heparan sulfate, chondroitin sulfate A and C, and hyaluronic acid) preincubated with MK at 50 ng/ml were examined. The enhancing activity of MK was completely suppressed by heparin at 600 ng/ml but not by the other compounds. The effects of MK during IVM were also tested on oocytes freed from granulosa cells (GCs). When the denuded oocytes were cultured in IVM medium, no blastocyst formation after IVF was observed, regardless of MK supplementation. However, coculture of the denuded oocytes with isolated GC pellets enhanced the cleavage rates and the blastocyst yield, and these effects were more pronounced with MK supplementation. These results indicate that the presence of MK during IVM of bovine granulosa-enclosed oocytes can enhance their developmental competence to the blastocyst stage after IVF and suggest that the enhancing effects might be mainly mediated by GCs.

Animals↗
PubMed2000

The anticonvulsant effects of volatile anesthetics on penicillin-induced status epilepticus in cats.

UNLABELLED: Volatile anesthetics may be used to treat status epilepticus when conventional drugs are ineffective. We studied 30 cats to compare the inhibitory effects of sevoflurane, isoflurane, and halothane on penicillin-induced status epilepticus. Anesthesia was induced and maintained with one of the three volatile anesthetics in oxygen. Penicillin G was injected into the cisterna magna, and the volatile anesthetic discontinued. Once status epilepticus was induced (convulsive period), the animal was reanesthetized with 0.6 minimum alveolar anesthetic concentration (MAC) of the volatile anesthetic for 30 min, then with 1.5 MAC for the next 30 min. Electroencephalogram and multiunit activity in the midbrain reticular formation were recorded. At 0.6 MAC, all anesthetics showed anticonvulsant effects. Isoflurane and halothane each abolished the repetitive spike phase in one cat; isoflurane reduced the occupancy of the repetitive spike phase (to 27%+/-22% of the convulsive period (mean +/- SD) significantly more than sevoflurane (60%+/-29%; P < 0.05) and halothane (61%+/-24%; P < 0.05), and the increase of midbrain reticular formation with repetitive spikes was reduced by all volatile anesthetics. The repetitive spikes were abolished by 1.5 MAC of the anesthetics: in 9 of 10 cats by sevoflurane, in 9 of 9 cats by isoflurane, and in 9 of 11 cats by halothane. In conclusion, isoflurane, sevoflurane, and halothane inhibited penicillin-induced status epilepticus, but isoflurane was the most potent. IMPLICATIONS: Convulsive status epilepticus is an emergency state and requires immediate suppression of clinical and electrical seizures, but conventional drugs may be ineffective. In such cases, general anesthesia may be effective. In the present study, we suggest that isoflurane is preferable to halothane and sevoflurane to suppress sustained seizure.

Anesthetics, Inhalation↗
PubMed2000

The anticonvulsant effects of volatile anesthetics on lidocaine-induced seizures in cats.

UNLABELLED: Large concentrations of sevoflurane and isoflurane, but not halothane, induce spikes in the electroencephalogram. To elucidate whether these proconvulsant effects affect lidocaine-induced seizures, we compared the effects of sevoflurane, isoflurane, and halothane in cats. Fifty animals were allocated to 1 of 10 groups: 70% nitrous oxide (N2O), 0.6 minimum alveolar anesthetic concentration (MAC) + 70% N2O, 1.5 MAC + 70% N2O, and 1.5 MAC of each volatile agent in oxygen. Lidocaine 4 mg x kg(-1) x min(-1) was infused IV under mechanical ventilation with muscle relaxation. Electroencephalogram in the cortex, amygdala, and hippocampus and multiunit activities in the midbrain reticular formation (R-MUA) were recorded. Lidocaine induced spikes first from the amygdala or hippocampus in the 70% N2O and halothane groups and from the cortex in the sevoflurane and isoflurane groups. Lidocaine induced seizures in all cats in the 70% N2O and 0.6 MAC + N2O groups. Seizure occurrence was reduced in the 1.5 MAC + N2O group (P < 0.05 versus 70% N2O). The onset of seizure was delayed in the 0.6 MAC + N2O and 1.5 MAC groups for sevoflurane and isoflurane, but not for halothane, compared with the 70% N2O group (P < 0.05). Lidocaine increased R-MUA with seizure by 130%+/-56% in the 70% N2O group. The increase of R-MUA with seizure was more suppressed in the volatile anesthetic groups than in the 70% N2O group (P < 0.05). In the present study, sevoflurane and isoflurane attenuated seizure when the blood lidocaine concentration was accidentally increased. IMPLICATIONS: Increasingly, epidural blockade is combined with general anesthesia to achieve stress-free anesthesia and continuous pain relief in the postoperative period. In the present study, sevoflurane and isoflurane attenuated seizure when the blood lidocaine concentration was accidentally increased.

Anesthetics, Inhalation↗