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Biomedical subjects

N Watanabe

Publications and source records attributed to N Watanabe.

At least 271 records · Page 15Linked to original sources
PubMed1999

Physiological roles of gammadelta T-cell receptor intraepithelial lymphocytes in cytoproliferation and differentiation of mouse intestinal epithelial cells.

In this study we aimed to elucidate the physiological role of gammadelta intraepithelial lymphocytes (IEL) in the mouse intestine. For this purpose, we used T-cell receptor (TCR) Vgamma4/Vdelta5 transgenic mice (KN 6 Tg: BALB/c background, H-2d), and compared the immunological and physiological characteristics of the intestinal tracts of KN 6 Tg and non-transgenic (non-Tg) littermates. In KN 6 Tg littermates, 95% of small intestinal (SI) and large intestinal (LI) IEL expressed gammadelta TCR, and their TCR was replaced by Tg gammadelta TCR. In these mice, class II major histocompatibility complex (MHC) expression was up-regulated in the SI epithelium, compared with the non-Tg littermates, under specific pathogen-free (SPF) conditions. Competitive reverse transcription-polymerase chain reaction (RT-PCR) analysis showed that the mRNAs of the I-Ealpha chain on the SI epithelial cells was higher in KN 6 Tg than in non-Tg littermates. However, in the LI, class II MHC molecules were not expressed in either KN 6 Tg or non-Tg littermates. The epithelial cell mitotic index in the SI, but not in the LI, was higher in KN 6 Tg than in non-Tg littermates under SPF conditions. However, differentiation markers for SI epithelial cells, such as alkaline phosphatase and disaccharidase (lactase, maltase and sucrase) activities, were similar in KN 6 Tg and non-Tg littermates. MHC class II molecule expression on the SI epithelium was absent in germ-free (GF) Tg mice, but was induced under SPF conditions, coinciding with the increase of interferon-gamma (IFN-gamma) mRNA in gammadelta TCR SI-IEL. These findings suggest that gammadelta TCR IEL regulate epithelial cell regeneration and class II MHC expression, but not cell differentiation in the SI. However, these functions were not observed in the gammadelta TCR IEL in the LI. In addition, the activation step in the gammadelta TCR SI-IEL is dependent on the presence of gut microflora.

Alkaline Phosphatase↗
PubMed1999

Isopower maps of the electrogastrogram (EGG) after total gastrectomy or total colectomy.

Isopower or topographic electrogastrograms (EGG) correspond to topographic electroencephalograms. Both project the topographic localizations of the spectral frequencies on the abdominal surface or scalp. This paper compares the pre-operative control isopower EGG maps with those of total gastrectomy or total colectomy. EGGs were recorded simultaneously at 27 locations on the epigastro-abdominal surface. Spectral analysis by the maximal entropy method (MEM) was performed and the ensemble means of pre-prandial and post-prandial spectra were calculated. The spectral frequencies were arbitrarily classified into five groups, 1 cycle per minute (cpm) (0-2.4 cpm), 3 cpm (2.5-4.9 cpm), 6 cpm (5.0-7.4 cpm), 8 cpm (7.5-9.9 cpm) and 10 cpm (10.0-12.9 cpm). Maximal power peaks in each spectral group, and electrode locations which were expressed by x-y coordinates were the indicators for making the isopower EGG maps by using a contour map program. Thereafter, the maximal power spots or foci in each spectral group were determined. The pre-operative maximal power foci of the 1, 8 and 10 cpm groups were distributed rather evenly on the epigastro-abdominal surface. Those of the 3 and 6 cpm groups, mainly concentrated in the epigastric region, were absent in almost all patients who had undergone total gastrectomy. The infra-umbilical foci of the 3 and 6 cpm groups completely disappeared after total colectomy. The infra-umbilical foci of the 3 and 6 cpm groups (2.5-7.4) may reflect the colonic activities and the epigastric 3 cpm foci, the gastric activities. The pre-operative maximal power of the 3 cpm foci decreased significantly after total or sub-total gastrectomy.

Adult↗
PubMed1999

Ceftizoxime-induced hemolysis due to immune complexes: case report and determination of the epitope responsible for immune complex-mediated hemolysis.

BACKGROUND: Several occurrences of immune complex-mediated, cephalosporin-induced intravascular hemolysis have been reported. This report describes the first case of hemolytic anemia caused by an immune-complex mechanism associated with ceftizoxime and delineates the epitope responsible for hemolysis. CASE REPORT: The patient's serum was tested for antibody that reacted with five penicillins and 30 cephems (all types of cephalosporins) by using protocols to detect drug-adsorption and immune-complex mechanisms. The patient's antibody that formed immune complexes with ceftizoxime reacted with 10 of 30 cephems. These 10 drugs were classified as oxime-type cephalosporins, which have a common structural formula consisting of [(Z)-2-(2-amino-4-thiazolyl)-2-methoxyiminoacetoamido] at the C7 position on 7-aminocephalosporinic acid with or without substitution at the C3 position. CONCLUSION: The patient's antibody recognized a common structure in 10 oxime-type cephalosporins, and immune complexes formed by the antibody specifically or nonspecifically bound to red cell membranes. Therefore, when intermittent antibiotic therapy is required, as in this case, care should be taken in antibiotic selection to avoid drug-induced hemolytic anemia. In addition, when this type of hemolysis is observed, tests for antibody that reacts by adsorption and immune-complex mechanisms should be performed against penicillins and cephems to select antibiotics not showing a cross-reaction.

Adsorption↗
PubMed1999

Absence of R1066X mutation in six Japanese patients with Dubin-Johnson syndrome.

The Dubin-Johnson syndrome (DJS) is a rare autosomal recessive liver disease characterized by chronic conjugated hyperbilirubinemia. The phenotype of this syndrome is thought to be caused by the impaired expression of the canalicular multispecific organic anion transporter (cMOAT), which transports non-bile salt organic anions into the bile. Recently, a mutation from arginine (Arg) to stop-codon at codon 1066 in the cMOAT gene has been reported in one Caucasian patient with DJS. In this study, we investigated whether this mutation is found in Japanese patients with DJS. Genomic DNAs were extracted from the leukocytes of six Japanese patients and the fragments spanning codon 1066 were amplified by polymerase-chain reaction. The digest of the amplified fragments with a restriction enzyme, Taql, demonstrated that all of six patients did not exhibit an R1066X mutation. No mutation at Arg1066 was also confirmed by direct sequencing of the amplified products. These findings suggested that this R1066X mutation was not a major mutation in Japanese patients with DJS. Further investigation will be required in an attempt to search other mutations in cMOAT gene in Japanese patients with DJS.

Adult↗
PubMed1999

Augmentation of vecuronium-induced neuromuscular block during sevoflurane anaesthesia: comparison with balanced anaesthesia using propofol or midazolam.

We have quantified the potentiating effects of 1.7% sevoflurane (n = 12) on vecuronium-induced neuromuscular block and compared the results with those obtained during balanced anaesthesia with propofol (n = 12) or midazolam (n = 12) in 36 patients. Neuromuscular function was monitored using an accelerograph and the train-of-four responses of the adductor pollicis muscle to ulnar nerve stimulation. Vecuronium 0.1 mg kg-1 was administered as an intubating dose, and maintenance doses of 0.02 mg kg-1 were administered on three occasions when T1/T0 had recovered to 25%. Thereafter, spontaneous recovery was monitored until complete. Times to 25% recovery of T1/T0 (DUR25) after an intubating dose of vecuronium did not differ between groups (mean 44.2 (SD 18.7) min for sevoflurane, 38.3 (7.5) min for propofol and 35.5 (9.5) min for midazolam). DUR25 values after each maintenance dose were 29.8 (9.5) min, 30.3 (10.4) min and 31.6 (10.7) min during sevoflurane anaesthesia, and were significantly longer than values for propofol (21.7 (6.0) min, 21.5 (5.8) min and 21.9 (5.8) min) and midazolam (20.0 (5.9) min, 19.3 (7.7) min and 19.8 (8.0) min) (P < 0.05) in each case). Recovery index25-75% and interval from T1/T0 = 25% to T4/T1 = 0.7 after the final dose of vecuronium were significantly prolonged by sevoflurane (28.3 (13.2) min and 42.7 (16.4) min) compared with propofol (17.6 (6.1) min and 26.6 (9.8) min) or midazolam (16.3 (9.4) min and 26.0 (10.2) min) (P < 0.05 in each case).

Adult↗
PubMed1999

Preferential induction of guanine deletion at 5'-GGGA-3' in rat mammary glands by 2-amino- 1-methyl-6-phenylimidazo[4,5-b]pyridine.

2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) is known to induce a characteristic mutation, G deletion at the 5'-GGGA-3' site, preferentially in the lacI transgene of the colonic mucosa of Big Blue((R)) rats (BBR) and mice and specifically in the Apc gene of rat colon tumors. In this study, lacI mutations of the mammary glands in PhIP-treated rats were investigated. Six-week-old female (BBRxSprague-Dawley)F(1) rats were administered 10 gavages of 65 mg/kg/day PhIP. Mammary ducts were collected from the macroscopically normal mammary tissue of PhIP-treated and untreated rats at 56-69 weeks of age by collagenase treatment. The mutant frequencies were 25 +/- 2.1x10(-6) in control rats and 323 +/- 44x10(-6) in the PhIP-treated rats. By sequencing 40 and 177 mutants in the control and PhIP-treated groups, respectively, 34 and 149 mutations were considered independent mutations. In the control group, G:C-->A:T transitions at CpG sites dominated and no G:C deletions were detected. In the PhIP-treated group, G:C-->T:A transversions were most frequent (43%), followed by single base pair deletions of G:C (21%). A total of nine deletions were at 5'-GGGA-3' sites, accounting for 29% of the G:C deletions and 6% of the 149 total mutations. Clusters of more than three mutations at one nucleotide position were observed at 12 positions and two were G deletions at 5'-GGGA-3' sites. Comparison of the PhIP-induced mutations in the mammary glands with those previously reported in the colon revealed that G:C-->T:A transversions occurred at a significantly higher frequency in the mammary glands and that G:C deletions occurred at a significantly lower frequency. However, the signature mutation, G deletion at the 5'-GGGA-3' site, was commonly observed in both tissues.

Animals↗
PubMed1999

Identification and characterization of ligands for L-selectin in the kidney. I. Versican, a large chondroitin sulfate proteoglycan, is a ligand for L-selectin.

Ligands for a leukocyte adhesion molecule, L-selectin, are expressed not only in the specific vascular endothelium in lymph nodes and Peyer's patches but also in the extravascular tissues such as the brain white matter, choroid plexus and the kidney distal straight tubuli. However, the biological significance of these extravascular ligands is currently unknown. We now report the purification and characterization of a novel extravascular ligand for L-selectin in the kidney using a tubule-derived cell line, ACHN. Binding of L-selectin-IgG chimera (LEC-IgG) to the isolated ligand was specifically blocked with either (i) anti-L-selectin mAb, (ii) EDTA, (iii) fucoidan, (iv) chondroitin sulfate (CS) B or CS E, or (v) treatment with chondroitinases. Partial amino acid sequencing, Western blotting and immunoprecipitation analyses showed that a major ligand for L-selectin in ACHN cells is versican of 1600 kDa. Histochemical as well as biochemical analyses verified that a versican subspecies in the kidney was indeed reactive with L-selectin. Studies with cell lines including those derived from the kidney indicated that a certain glycoform and/or splice form of versican is reactive with L-selectin. Under pathological conditions such as those induced by unilateral ureteral obstruction, versican was shed from the distal straight tubuli and became localized in the adjacent vascular bundles around which a substantial leukocyte infiltration was concomitantly observed. Possible involvement of versican in leukocyte trafficking into the kidney under diseased conditions is discussed.

Animals↗
PubMed1999

Identification and characterization of ligands for L-selectin in the kidney. III. Characterization of L-selectin reactive heparan sulfate proteoglycans.

L-Selectin, a leukocyte adhesion molecule, mediates leukocyte rolling on the endothelium and plays a critical role in leukocyte recruitment at inflammatory sites as well as in lymphocyte homing. We have previously shown that L-selectin reactive chondroitin sulfate and heparan sulfate proteoglycans (HSPGs) are both expressed in the distal tubules of the kidney and that versican is one of the chondroitin sulfate-type ligands. In the present study, we characterized the heparan sulfate-type ligand(s) in more detail. The molecular sizes of HSPGs were approximately 600 kDa with core protein sizes of 160 and 180 kDa. Western blotting analysis showed that L-selectin reactive HSPGs were neither agrin nor perlecan, major basement membrane HSPGs in the kidney. The binding to L-selectin was mediated by the lectin domain of L-selectin in a Ca2+-dependent manner and required heparan sulfate side chains, but not sialic acid. To our knowledge, this is the first biochemical characterization of the L-selectin reactive heparan sulfate proteoglycan(s) in the distal tubules of the kidney.

Animals↗
PubMed1999

Periciliary structure of developing rat photoreceptor cells. A deep etch replica and freeze substitution study.

The purpose of this study is to identify the morphological machinery for selective transport of proteins required in the outer segments of the rat photoreceptor cell. As a first step, the three-dimensional architecture of the periciliary region and its developmental changes were examined. Freeze-deep-etching and freeze-substitution methods combined with rapid freezing technique were used. The apical surface of the inner segment was swollen and partially enclosed the base of the connecting cilium in early postnatal stages, so that the basal region of the connecting cilium was inevitably surrounded by a groove. However, a specialized periciliary ridge complex as seen in frog photoreceptor cells has never been observed in rat photoreceptor cells. The cytoplasmic surface of the plasma membrane of the apical inner segment in the vicinity of the connecting cilium was covered with loose fine filaments. However, it was unlikely to be a possible structural candidate for selective transport of membrane proteins. This study also revealed the interior structure of the connecting cilium. Actin filaments in the distal axonem formed a complicated meshwork together with an unknown substance. Since S1 decorated filaments were not detected in the middle region of the connecting cilium, actin filaments at the base of outer segment seem to be independently polymerized locally from G-actin that is transported from the inner segment.

Animals↗
PubMed1999

Differential uptake of TI-201 by small-cell lung cancer in a patient with pneumoconiosis-related pulmonary nodules.

A 68-year-old man with pneumoconiosis was thought to have small-cell lung cancer based on the results of a biopsy of a bone tumor. Three pulmonary nodules were observed on a chest radiograph. Compared with a chest radiograph taken 4 months earlier, one of the nodules had grown. It was difficult to differentiate this nodule from pneumoconiosis-related benign pulmonary nodules from the appearance on the chest radiograph and CT. Ga-67 scintigraphy and TI-201 lung SPECT were performed to characterize these nodules. TI-201 SPECT showed differential high uptake in the enlarged nodule, whereas Ga-67 scintigraphy showed equally intense uptake in all these nodules. Transbronchial biopsy of the nodule that showed high TI-201 uptake revealed cancer cell nests against a background of interstitial fibrosis. The pathologic diagnosis was small-cell lung cancer that had developed in lung scar tissue. This case suggests the utility of TI-201 in scintigraphic assessments of pneumoconiosis-related pulmonary nodules when lung cancer is suspected.

Aged↗
PubMed1999

Tissue engineering of ligament and tendon healing.

Ligaments and tendons are bands of dense connective tissue that mediate normal joint movement and stability. Injury to these structures may result in significant joint dysfunction because they either heal by production of inferior matrix or do not heal at all. The process of ligament and tendon healing is complex and the roles of cellular and biochemical mediators continue to be elucidated. The expression of growth factors and growth factor receptors is modulated after injury, and cells from healing tissues are responsive to growth factors. Tissue engineering offers the potential to improve the quality of ligaments and tendons during the healing process. The concept is based on the manipulation of cellular and biochemical mediators to affect protein synthesis and improve tissue remodeling. Recently, novel techniques such as application of growth factors, gene transfer techniques, and cell therapy have shown promise and may become effective biologic therapies in the future. Many groups have been successful in introducing marker and therapeutic genes into ligaments and tendons. Cell therapy involves the introduction of mesenchymal progenitor cells as a pluripotent cell source into the healing environment. The combination of cell therapy with growth factor application via gene transfer offers new avenues to improve ligament and tendon healing.

Animals↗
PubMed1999

Early response of tumour to radiotherapy should be assessed by both uptake and retention of single photon tracers: in vitro analysis with 201Tl-chloride, 99Tcm-sestamibi and 99Tcm-tetrofosmin in human bladder cancer cells and human leukocytes.

The uptake and retention of single photon tracers in irradiated tumour cells was observed in an attempt at the early evaluation of the effect of radiation. T24 human bladder cancer cells were exposed to a single dose of 10 Gy or 20 Gy or a fractionated dose of 10 Gy (2 Gy for 5 days). The uptake of 201Tl chloride, 99Tcm-sestamibi and 99Tcm-tetrofosmin was observed by incubating in vitro for 60 min. The retention of the tracers was observed at 60 min after changing the incubation medium for a tracer-free medium. Uptake per culture well of all tracers in the cells exposed to 20 Gy declined as viable cell number decreased, but uptake per cell increased progressively. Uptake per cell of all tracers in the cells exposed to either a single dose or a fractionated dose of 10 Gy also increased, while a delay in growth was observed. The retention of these tracers decreased during this period and recovered thereafter. A binding assay with purified human leukocytes indicated that assessment with 99Tcm-sestamibi and 99Tcm-tetrofosmin is influenced by inflammatory cells. In conclusion, the effect of radiation may be underestimated if assessed by tracer uptake alone because of the increase in tracer uptake in viable irradiated cells. Observation of the retention of tracers may provide additional information.

Humans↗
PubMed1999

Human immunodeficiency virus type 1 Vpr modifies cell proliferation via multiple pathways.

Vpr, one of the accessory molecules of HIV-1, has been demonstrated to arrest the cell cycle at the G2 phase. This Vpr-mediated cell cycle arrest is implicated to have an important role in the viral life cycle. In the present study, we quantitate the extent of Vpr-mediated cell cycle arrest with the use of a bicistronic vector consisting of a vpr gene and a green fluorescence protein sequence. Using this system, we examined the effect of several Vprs on cell cycle progression and growth of cells from different species quantitatively. We found that Vpr from the T-cell line-adapted HIV-1SF2 strain (Vpr2) could not significantly induce G2 arrest in HeLa cells but was able to induce it in 293T cells. However, strong inhibition of cell proliferation in HeLa cells as well as in 293T cells was observed by Vpr2. This ability of Vpr2 to inhibit cell proliferation without G2 arrest was also observed when expressed in monkey cell line. Analyses of chimeric Vprs revealed that this species-non-specific growth inhibitory activity of Vpr was not mediated solely by the C-terminal region of Vpr. These results indicated that the growth inhibitory activity of Vpr is independent of its G2 arresting activity. In addition, the species-non-specific nature of this activity suggests that Vpr has a novel mechanism to retard cell proliferation by influencing basic cellular functions.

Adaptation, Biological↗
PubMed1999

Relationship between serum levels of anti-low-density lipoprotein-acetaldehyde-adduct antibody and aldehyde dehydrogenase 2 heterozygotes in patients with alcoholic liver injury.

We prepared low-density lipoprotein (LDL)-acetaldehyde-adduct (hereafter abbreviated as LDL-adduct) and anti-LDL-adduct antibody by using Watanabe hyperlipidemic rabbits, and determined values of serum anti-LDL-adduct antibody levels by the ELISA method in healthy adults and patients with alcoholic liver injury. In the nondrinking group in healthy adults, values of anti-LDL-adduct antibody levels were 25 +/- 13 microg/ml, and there was no significant difference between moderate drinkers without diseases and the nondrinking group in healthy adults. Values of anti-LDL-adduct antibody in alcoholic disease groups, 17 +/- 9 microg/ml for the patients with the fatty liver group, 21 +/- 14 microg/ml for the hepatic fibrosis group, 70 +/- 21 microg/ml for the alcoholic hepatitis group, 41 +/- 50 microg/ml for the alcoholic cirrhosis group, and 19 +/- 18 microg/ml for the alcoholic pancreatitis group. Examinations of aldehyde dehydrogenase 2 (ALDH2) genetic variations by the polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP) method in the healthy group and the liver injury group revealed a tendency for patients with ALDH2(1)/2(2) in the liver injury group to have relatively mild liver lesions. When comparing anti-LDL-adduct antibody levels between ALDH2 genetic variations, those for the patients with ALDH2(1)/2(2) (36 +/- 40 microg/ml) were significantly higher than those for patients with ALDH2(1)/2(2) (11 +/- 5 microg/ml). Results of the present study suggest that genetic variation may influence the progression of liver injury.

Acetaldehyde↗
PubMed1999

Mechanisms of hepatic microcirculatory disturbances induced by acute ethanol administration in rats, with special reference to alterations of sinusoidal endothelial fenestrae.

Elucidation of the hepatic hemodynamics in acute ethanol administration is an issue of clinical importance for better understanding of alcoholic liver diseases. The purpose of this study is to clarify the mechanism of hepatic microcirculatory disturbances after acute ethanol administration, especially regarding the effects of ethanol on alterations of sinusoidal endothelial fenestrae (SEF) and the involvement of endothelin-1 (ET-1) in the mechanism of portal hypertension induced by ethanol. Ethanol was administrated into the portal vein via the mesenteric vein branch of rats as a continuous infusion (4 and 8 mg/min of ethanol) for 60 min. Hepatic tissue blood flow measured with a laser Doppler blood flowmeter was found to be remarkably decreased with time, whereas portal pressure began to increase at 10 min and showed a significant increase by approximately 1.5 cm H2O at 60 min. Ethanol concentrations in blood at 60 min after 4 and 8 mg/min of ethanol infusion were 0.75 mg/ml and 1.77 mg/ml, respectively. At this point, scanning electron microscopy revealed significant decreases in number and diameter of SEF both in zone 1 and zone 3, with the increase in ethanol level. These findings suggested that decreases in number and diameter of SEF, whether primary or secondary, may lead to the impairment of the transport of plasma substances from sinusoids to hepatocytes in acute ethanol administration. Furthermore, the pretreatment of BQ-123 inhibited a decrease in hepatic tissue blood flow and an increase in portal pressure caused by ethanol, indicating that ET-1 may be involved in the mechanism of hepatic circulatory disturbances in acute ethanol administration.

Animals↗
PubMed1999

Distribution of insertion sequence-like element IS1272 and its position relative to methicillin resistance genes in clinically important Staphylococci.

The distribution of insertion sequence-like element IS1272 was analyzed for clinical isolates of Staphylococcus aureus, Staphylococcus epidermidis, and Staphylococcus haemolyticus. In each of the staphylococcal species, IS1272 was detected in both methicillin-resistant (MR) and methicillin-susceptible strains of different genetic types. In MR isolates, IS1272 was generally located downstream of the truncated mecR1 gene (DeltamecR1), with an identical junction sequence occurring between DeltamecR1 and IS1272, although insertion of an additional gene sequence in the junction sequence was detected in one S. epidermidis isolate. These findings suggest that the mec element with the rearranged form of mecR1 (DeltamecR1-IS1272) has been transmitted to multiple clones of staphylococci.

Bacterial Proteins↗