Biomedical subjects

A Katoh

Publications and source records attributed to A Katoh.

At least 19 recordsLinked to original sources

PubMed2002

Non-HTLV-1-associated primary gastric T-cell lymphomas show cytotoxic activity: clinicopathological, immunohistochemical characteristics and TIA-1 expression in 31 cases.

AIMS: Most primary gastrointestinal lymphomas are of B-cell origin and T-cell origin is very rare. Recent studies have suggested that human T-cell lymphotrophic virus type 1 (HTLV-1) may be involved in the development of primary gastric T-cell lymphoma. We analysed 31 patients with primary gastric T-cell lymphoma in south-west Japan, an area endemic for HTLV-1, and determined their phenotypes, genotypes, and HTLV-1 status. METHODS AND RESULTS: Here we present 31 cases of primary gastric T-cell lymphoma in a HTLV-1-endemic area in Japan and analyse the clinical status, histology, phenotype and virus status. The median age at onset of primary gastric T-cell lymphoma was 57 years with a gender ratio of M:F = 1.58:1. Six of the 31 primary gastric T-cell lymphoma cases had HTLV-1 proviral DNA (five males, one female), nine of the 31 cases were positive for anti-adult T cell leukaemia antibody, without examination of HTLV-1 proviral DNA (five males, four females), eight were non-HTLV-1-associated primary gastric T-cell lymphoma (four males, four females) and the other eight cases were unknown. Primary gastric T-cell lymphoma usually presented as a large ulcerated tumour at the corpus to the antrum and histologically consisted of anaplastic large cell type (n = 2), pleomorphic large cell type (n = 3), pleomorphic medium and large cell type (n = 14), pleomorphic medium cell type (n = 11), and angioimmunoblastic T-cell lymphoma type (n = 1). There were no clear macroscopic and microscopic differences between HTLV-1-associated and non-HTLV-1-associated primary gastric T-cell lymphoma. Most patients died within 2 years of diagnosis, and both types of primary gastric T-cell lymphoma (with and without HTLV-1) were associated with poor prognosis. Cytotoxic marker analysis showed that HTLV-1-associated lymphomas were negative for TIA-1, while non-HTLV-1-associated lymphomas were positive for TIA-1. CONCLUSIONS: Our results suggest that in HTLV-1-endemic areas, patients with HTLV-1-associated primary gastric T-cell lymphoma should be managed carefully and that TIA-1 seems to be useful for identifying the aetiology of this lesion.

Adult↗

PubMed2001

Mobilization of endothelial progenitor cells in patients with acute myocardial infarction.

BACKGROUND: Endothelial progenitor cells (EPCs) circulate in adult peripheral blood (PB) and contribute to neovascularization. However, little is known regarding whether EPCs and their putative precursor, CD34-positive mononuclear cells (MNC(CD34+)), are mobilized into PB in acute ischemic events in humans. METHODS AND RESULTS: Flow cytometry revealed that circulating MNC(CD34+) counts significantly increased in patients with acute myocardial infarction (n=16), peaking on day 7 after onset, whereas they were unchanged in control subjects (n=8) who had no evidence of cardiac ischemia. During culture, PB-MNCs formed multiple cell clusters, and EPC-like attaching cells with endothelial cell lineage markers (CD31, vascular endothelial cadherin, and kinase insert domain receptor) sprouted from clusters. In patients with acute myocardial infarction, more cell clusters and EPCs developed from cultured PB-MNCs obtained on day 7 than those on day 1. Plasma levels of vascular endothelial growth factor significantly increased, peaking on day 7, and they positively correlated with circulating MNC(CD34+) counts (r=0.35, P=0.01). CONCLUSIONS: This is the first clinical demonstration showing that lineage-committed EPCs and MNC(CD34+), their putative precursors, are mobilized during an acute ischemic event in humans.

Aged↗

PubMed2001

Two members of the IgLON family are expressed in a restricted region of the developing chick brain and neural crest.

The precise expression patterns of two IgLON genes, CEPU-1 and limbic system-associated membrane protein (LAMP), were studied during early embryogenesis. It was found that expression of both was localized to restricted regions of the brain and neural crest. In the developing neural tube, CEPU-1 was expressed in the isthmus and a restricted region of the hindbrain, whereas LAMP was expressed in the anterior midbrain. Most neural crest cells expressed LAMP, whereas CEPU-1 expression was limited to crest cells derived from the hindbrain. These results suggest that members of the IgLON family have important roles during embryogenesis, particularly in brain formation and differentiation.

Animals↗

PubMed2001

Functional anatomy of musical perception in musicians.

The present study used functional magnetic resonance to examine the cerebral activity pattern associated with musical perception in musicians and non-musicians. Musicians showed left dominant secondary auditory areas in the temporal cortex and the left posterior dorsolateral prefrontal cortex during a passive music listening task, whereas non-musicians demonstrated right dominant secondary auditory areas during the same task. A significant difference in the degree of activation between musicians and non-musicians was noted in the bilateral planum temporale and the left posterior dorsolateral prefrontal cortex. The degree of activation of the left planum temporale correlated well with the age at which the person had begun musical training. Furthermore, the degree of activation in the left posterior dorsolateral prefrontal cortex and the left planum temporale correlated significantly with absolute pitch ability. The results indicated distinct neural activity in the auditory association areas and the prefrontal cortex of trained musicians. We suggest that such activity is associated with absolute pitch ability and the use-dependent functional reorganization produced by the early commencement of long-term training.

Adult↗

PubMed2001

Long-term smoking causes nitroglycerin resistance in platelets by depletion of intraplatelet glutathione.

We investigated whether platelet responsiveness to nitroglycerin (NTG) is maintained in long-term smokers and if not, the mechanism. In the absence or presence of NTG, intraplatelet reduced glutathione (GSH) levels and ADP-induced platelet aggregation and intraplatelet cGMP levels were measured in 10 long-term smokers and 10 age-matched nonsmokers. The intraplatelet GSH level was significantly lower in smokers than in nonsmokers (P<0.05). Platelet aggregation was dose-dependently inhibited by NTG in both groups; however, inhibition was significantly weaker in smokers. N-acetylcysteine (1 mmol/L), an exogenous thiol agent, significantly potentiated NTG-induced platelet inhibition in nonsmokers but not in smokers. The ADP-induced intraplatelet cGMP level was significantly greater in the presence of NTG in nonsmokers but not so in smokers. Because the effects of long-term smoking are multifactorial, a rabbit model was made by chronic administration of buthionine sulfoximine (BSO, n=6) to decrease intraplatelet GSH. The intraplatelet GSH level was significantly lower in BSO-treated rabbits than in saline-treated rabbits (P<0.001). The NTG-induced inhibition of platelet aggregation was significantly weaker in BSO rabbits. N-acetylcysteine-induced potentiation was not observed in BSO rabbits, whereas significant potentiation was found in saline rabbits. These findings were similar to those of long-term smokers. In contrast, the intraplatelet GSH-to-oxidized glutathione ratio, which represents the redox state of glutathione, was significantly lower in smokers than in nonsmokers, whereas no difference was found between saline rabbits and BSO rabbits. In conclusion, long-term smoking causes NTG resistance to aggregation in platelets, possibly through the depletion of intraplatelet GSH.

Animals↗

PubMed2001

Sequence characterization of the vir region of a nopaline type Ti plasmid, pTi-SAKURA.

We isolated a crown gall tumor-inducing nopaline type Ti plasmid from Agrobacterium tumefaciens on a Sakura Japanese cherry tree, and designated it as pTi-SAKURA. By primer walking sequencing with long PCR and a newly developed PCR subcloning technique for long insert DNA, we completed DNA sequencing of the most important functional unit, the virulence (vir) region of pTi-SAKURA, which is indispensable for T-DNA transfer into the plant's chromosomes. By homology searches with the vir genes of other bacterial plasmids, we identified 11 open reading frames (orfs) and 31 genes and 11 vir box, which are 6 bp regulatory sequences. In total, 26 vir genes, including the putative virF and virK and the main vir region, were present as the vir gene cluster. The presence of vir box, GC content, codon usage and expression analysis in these genes led us to propose a new vir region.

Agrobacterium tumefaciens↗

PubMed2001

[Plication of the sinotubular junction for aneurysm of the ascending aorta associated with aortic regurgitation: a case report].

A 63-year-old woman with aneurysm of the ascending aorta associated with AR due to dilatation of the sinotubular junction (STJ) and with poor LV function, who did not have Marfan syndrome, underwent a plication of the STJ and replacement of the ascending aorta. In operation, we simultaneously performed the plication of dilated STJ (60 mm) and the replacement of ascending aorta using a 26 mm Woven Dacron graft. Post-operative angiogram (1 POM) showed no aortic regurgitation and good recovery of the LV function. This procedure is less invasive, and indicated for patients without significant elongation or thickening of the aortic valve, especially when the patients have higher risk.

Aorta↗

PubMed2000

Hypercholesterolemia inhibits angiogenesis in response to hindlimb ischemia: nitric oxide-dependent mechanism.

BACKGROUND: Endothelium-derived nitric oxide (EDNO) plays an important role in the regulation of angiogenesis, whereas hypercholesterolemia (HC) impairs EDNO release. We examined the hypothesis that HC may inhibit ischemia-induced angiogenesis by inhibition of EDNO in a rat model of unilateral hindlimb ischemia and that oral L-arginine supplementation, a substrate for NO synthase, may prevent HC-related impairment of angiogenesis. METHODS AND RESULTS: Male Sprague-Dawley rats were fed (A) standard diet (control), (B) 2% high-cholesterol diet (HC group), or (C) high-cholesterol diet with oral L-arginine (2.25% in drinking water) (HC+L-arg group). At 2 weeks of the dietary intervention, unilateral limb ischemia was surgically induced in all animals. Dietary HC groups (B and C) revealed elevated total and LDL cholesterol levels compared with control animals. Laser Doppler blood flow analyses showed significant decreases in the ischemic/normal limb blood flow ratio in the HC group compared with controls (P:<0.05) when followed up until 4 weeks after surgery. Selective angiography and immunohistochemical analyses in the ischemic limb at postoperative day 14 revealed significantly lower angiographic scores (P:<0.01) and capillary densities (P:<0.01) in the HC group than controls, which were associated with decreased tissue contents of NO(x) and cGMP. Oral L-arginine supplementation (HC+L-arg) significantly improved all parameters of the laser Doppler blood perfusion ratio, angiographic scores, and capillary densities (P:<0.01 versus HC group), which were accompanied by significant elevations in serum L-arginine levels and tissue NO(x) and cGMP contents. CONCLUSIONS: Collateral vessel formation and angiogenesis in response to hindlimb ischemia were significantly attenuated in rats with dietary HC. The mechanism may be related to the reduced NO bioactivity in the ischemic tissues. Augmentation of the tissue NO activity by oral L-arginine supplementation restored the impaired angiogenesis in HC.

Administration, Oral↗

PubMed2000

Involvement of glial fibrillary acidic protein (GFAP) expressed in astroglial cells in circadian rhythm under constant lighting conditions in mice.

To clarify the role of glial fibrillary acidic protein (GFAP)-expressed glial cells in the circadian clock, we examined GFAP expression in the suprachiasmatic nucleus (SCN) and the intergeniculate leaflet (IGL) under various lighting conditions in mice. We demonstrated that GFAP expression did not show daily change in the SCN under a light-dark cycle; however, long-term housing under constant lighting conditions led to dramatic changes in GFAP expression, i.e., a decrease in the SCN and an increase in the IGL. Furthermore, mice that had a targeted deletion in the GFAP gene (GFAP mutant mice) showed longer and more arrhythmic circadian activity rhythms in constant lighting conditions than wild-type mice, while GFAP mutant mice exhibited stable circadian rhythms both in a light-dark cycle and constant darkness, and showed normal entrainment to environmental light stimuli. These results suggest that the GFAP-expressed astroglial cells in the SCN and the IGL may have some role in circadian oscillation under constant lighting conditions.

Animals↗

PubMed2000

Dynamic characteristics and adaptability of reflex eye movements of Fyn-kinase-deficient mice.

Fyn-kinase is expressed widely in the entire brain, including the cerebellum. Fyn-kinase-deficient mice are known to exhibit hypersensitivity to ethanol. To evaluate the cerebellar functions of Fyn-kinase, we examined the dynamic characteristics of the horizontal optokinetic response (HOKR) and vestibulo-ocular reflex (HVOR) and its adaptability in Fyn-kinase-deficient mice. The HOKR was induced by sinusoidal oscillation of a checkered screen and the HVOR was induced by sinusoidal oscillation of a turntable in darkness. The HOKR gains of mutant mice were higher than those of the wild-type mice, and the HVOR phases of mutant mice were less advanced than those of the wild-type mice. However, no difference was noted in the adaptability of the HOKR induced by 1 h of sustained screen oscillation between the mutant and wild-type mice. The cerebellar functions appear to be unaffected by Fyn-kinase knockout.

Animals↗

PubMed2000

Platelet-derived nitric oxide and coronary risk factors.

Platelet aggregation is inhibited through a negative feedback mechanism by the L-arginine/nitric oxide (NO) pathway found in platelets themselves. We have shown that long-term smoking impairs the bioactivity of platelet-derived NO (PDNO), resulting in an increased platelet aggregability. However, little is known about the relation between other coronary risk factors and PDNO release. Accordingly, this study was undertaken to examine whether other coronary risk factors are related to the impairment of PDNO bioactivity. We measured collagen-induced PDNO release with an NO-selective electrode in 61 subjects (mean age 47 years, range 24 to 74 years) who underwent complete physical and laboratory examinations. There was a significant inverse correlation between PDNO release and the number of coronary risk factors (r=-0.61, P<0. 001). Univariate analysis showed a significant inverse correlation between PDNO release and age (r=-0.33, P<0.01), mean arterial pressure (r=-0.40, P<0.002), total cholesterol level (r=-0.31, P<0. 02), and LDL-cholesterol level (r=-0.33, P<0.02). PDNO release was significantly lower in long-term smokers than in nonsmokers (P<0. 001). With multiple stepwise regression analysis, PDNO release correlated significantly and independently (r(2)=0.51), with smoking (F=37.8), age (F=7.1), and mean arterial pressure (F=5.1). Thus, we demonstrated that coronary risk factors are associated with an impairment of PDNO release by human platelets. Our findings may contribute to the understanding of the pathophysiological link between coronary risk factors and atherothrombotic disease.

Adult↗

PubMed2000

Growth of L929 cells on polymeric films prepared by Langmuir-Blodgett and casting methods.

The growth and spreading of fibroblast, L929 cells, on various polymeric films prepared by the Langmuir-Blodgett (LB) and casting methods were investigated. L929 cells, which were cultivated on collagen and synthetic polymeric films prepared by the LB method, adhered and spread much more than those on synthetic films prepared by the casting method. This is explained by the fact that cell growth and cell spreading are suitable for L929 cells on the films having serum proteins that contain a high alpha-helix content, because LB films adsorbed those serum proteins estimated from the circular dichroism measurements of the films immersed in cell culture medium. An exponential relationship was observed from the plot of the cell density vs root mean square of roughness of the films, which is estimated by atomic force microscopy, whereas a linear relationship was observed from the plot of the spreading ratio vs the root mean square of roughness. It is suggested that the correlation between the cell growth or spreading ratio and surface roughness of the films where L929 cells were cultivated is considered to be more important than the correlation between the cell growth or spreading ratio and the contact angle of the films.

Animals↗

PubMed2000

Gastrointestinal T cell lymphoma: predominant cytotoxic phenotypes, including alpha/beta, gamma/delta T cell and natural killer cells.

Gastrointestinal T cell lymphoma (TCL) is a rare subset of peripheral TCL, presenting with or without cytotoxic phenotype, a history of coeliac disease (CD) and enteropathy. However, CD is rare in Japan. Here, we describe the clinicopathological features of 18 Japanese cases. Lesions were found in the small intestine (n=13), stomach (n=3) and colon (n=2). Seven patients presented with enteropathy but none had a history of CD. Lymphomas appeared as ulceration (n=11), tumour formation (n=6), or polypoid growth (n=1). Histologically (REAL classification), neoplastic lesions were composed of intestinal type T cell lymphoma (ITCL, n=13, including one case with NK type), anaplastic large cell (ALCL, n=2), adult T cell leukaemia/lymphoma (ATLL, n=2), and lymphoblastic type (n=1). Epstein Barr virus infection was detected by EBER-1 in situ hybridization in 6 of 11 cases with ITCL but not in the other types. ALCL expressed CD30. CD56 was expressed in 3 of 11 cases of ITCL but not in other types. Among the 10 examined cases, 8 were alphabeta T cell type [CD2+, CD3+, T cell receptor (TCR)delta-1-, betaF1+], one was gammadelta T cell type [CD2+, CD3+, TCRdelta-1+, betaF1-], and the remaining case expressed natural killer (NK) cell type [CD2+, CD3-, CD56+, TCRdelta-1-, betaF1-]. Among the 8 examined cases, 3 expressed CD103 molecule, which was associated with extrathymic T cells of intraepithelial lymphocytes. All cases except ATLL expressed the cytotoxicity-associated molecule of TIA-1, and 11 of 14 TIA-1 positive cases expressed activated cytotoxic molecules of perforin, granzyme B, and/or Fas ligand. Despite the morphological, genetic and phenotypic heterogeneity, prognosis was poor, and 11 of 13 patients with small intestinal lesions died albeit appropriate treatment, but 3 of 4 patients with gastric or colonic lesions were still alive. The main cause of death was intestinal perforation. The latter might be due to the site specificity of small intestine and tumour cytotoxicity.

Adult↗

PubMed2000

[Ultrasonographic screening for thyroid cancer in the screening].

In our hospital, ultrasonography is performed for patients who come for thyroid cancer screening. Seventy-eight patients with thyroid cancer which was found by such screening were operated on from 1989 to 1998, while 287 patients with thyroid cancer found by other methods were operated on during the same period in our department. The age of the patients at surgery in the screening group was younger than that of the contrast group. In the screening group, 41 (52.6%) patients had small thyroid cancer, a higher rate that in the contrast group. Invasion of surrounding organs by the primary cancer was observed in only one patient (1.3%) in the screening group, a rate of invasion that was statistically lower than that in the contrast group. Twenty-six patients with benign thyroid disease detected in our screening were operated on during the same period. Careful selection of patients who need fine-needle aspiration cytology is demanded of head and neck surgeons, and careful evaluation of indicators is necessary to avoid surgery in the case of benign thyroid disease.

Adult↗

PubMed1999

Adhesive interaction between P-selectin and sialyl Lewis(x) plays an important role in recurrent coronary arterial thrombosis in dogs.

Cell adhesion molecules may play an important role in the disease process of acute coronary syndromes. We have shown a neutralizing anti-P-selectin monoclonal antibody and a sialyl Lewis(x)-containing oligosaccharide (SLe(x)-OS), an analogue of selectin ligand on leukocytes, reduce cyclic flow variations (CFVs) in a canine model of recurrent coronary arterial thrombosis, suggesting the important interaction between P-selectin and SLex for the pathophysiology of these syndromes. However, the functional role of these adhesion molecules in the thrombotic process remains unclear. Therefore, we investigated effects of SLe(x)-OS on CFVs, platelet P-selectin expression, and morphology of the stenotic site in the same model. Anesthetized open-chest dogs (n=34) were randomly divided into 4 groups after developing CFVs. Dogs intravenously received saline or graded doses of SLe(x)-OS (5, 20, or 40 mg/kg bolus) infusion followed by a continuous infusion (5 mg. kg-1. h-1) for 60 minutes. By flow cytometric analysis, P-selectin expression on platelets after CFVs was significantly upregulated during CFVs. Immunohistochemical analysis revealed the incorporation of platelets with upregulated P-selectin within thrombi at the stenotic site. Microscopic observations revealed the presence of numerous platelets adhered to leukocytes at the stenotic site on the damaged endothelium. SLe(x)-OS significantly reduced CFVs, inhibited the P-selectin expression on platelets, and prevented the adherence of platelets and leukocytes. These findings further support the notion that the adhesive interaction between P-selectin on platelets and SLe(x) on leukocytes plays an important role in platelet-mediated thrombus formation in this model.

Animals↗

PubMed1998

Dynamic characteristics and adaptability of mouse vestibulo-ocular and optokinetic response eye movements and the role of the flocculo-olivary system revealed by chemical lesions.

The dynamic characteristics of reflex eye movements were measured in two strains of chronically prepared mice by using an infrared television camera system. The horizontal vestibulo-ocular reflex (HVOR) and horizontal optokinetic response (HOKR) were induced by sinusoidal oscillations of a turntable, in darkness, by 10 degrees (peak to peak) at 0.11-0.50 Hz and of a checked-pattern screen, in light, by 5-20 degreesat 0.11-0.17 Hz, respectively. The gains and phases of the HVOR and HOKR of the C57BL/6 mice were nearly equivalent to those of rabbits and rats, whereas the 129/Sv mice exhibited very low gains in the HVOR and moderate phase lags in the HOKR, suggesting an inherent sensory-motor anomaly. Adaptability of the HOKR was examined in C57BL/6 mice by sustained screen oscillation. When the screen was oscillated by 10 degrees at 0.17 Hz, which induced sufficient retinal slips, the gain of the HOKR increased by 0.08 in 1 h on average, whereas the stimuli that induced relatively small or no retinal slips affected the gain very little. Lesions of the flocculi induced by local applications of 0. 1% ibotenic acid and lesions of the inferior olivary nuclei induced by i.p. injection of 3-acetylpyridine in C57BL/6 mice little affected the dynamic characteristics of the HVOR and HOKR, but abolished the adaptation of the HOKR. These results indicate that the olivo-floccular system plays an essential role in the adaptive control of the ocular reflex in mice, as suggested in other animal species. The data presented provide the basis for analyzing the reflex eye movements of genetically engineered mice.

Animals↗

PubMed1998

Endoscopic ligation for non-esophageal variceal upper gastrointestinal hemorrhage.

BACKGROUND: Endoscopic ligation can be used for bleeding lesions in non-fibrotic tissue; however, only small numbers of patients with non-esophageal variceal upper gastrointestinal hemorrhage have been treated in this way. To evaluate the utility of the technique, we performed the procedure to treat hemorrhage not from esophageal varices during emergency endoscopy. PATIENTS AND METHODS: Bleeding was identified from gastric Dieulafoy's ulcers (n=4), duodenal ulcers (n=3), gastric angiodysplasia (n=2) and Mallory-Weiss tears (n=3). The bleeding points were aspirated and controlled by endoscopic ligation and complete hemostasis was achieved in all cases. RESULTS: Although these lesions were located in difficult areas where endoscopic injection therapy and clipping sometimes fail, endoscopic ligation was performed easily and effectively without complications. Six of the patients had severe underlying disease, including acute and chronic myelogenous leukemia, liver cirrhosis and chronic renal failure; none suffered deterioration in their general condition after endoscopic ligation. CONCLUSIONS: Our findings suggest that endoscopic ligation is an easy and effective method of treatment for patients with gastrointestinal hemorrhage not from esophageal varices, and is safe even in patients with poor general health.

Adult↗

PubMed1998

Identification of the promoter region and the transcriptional regulatory sequence of the evgAS operon of Escherichia coli.

The evgAS operon of Escherichia coli encodes the EvgA response regulator and the EvgS sensory kinase, which are members of one of the two-component signal transduction systems of Escherichia coli. In this study, we identified the evg promoter and the EvgA-responsive element. Primer extension analysis found two evg transcriptional initiation sites, designated P1 (+1) and P2 (-10), and placed them 114 bp and 124 bp upstream of evgA, respectively. A gel retardation assay demonstrated that EvgA specifically bound to an inverted repeat located between -102 and -128 counting from P1. We also did a beta-galactosidase induction experiment using a promoter-probing vector and found that the EvgA-binding sequence was important to stimulate the evg promoter. These results suggest that the expression of evgAS is positively regulated by its own product, EvgA.

Bacterial Proteins↗