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Biomedical subjects

T Usui

Publications and source records attributed to T Usui.

At least 127 records · Page 7Linked to original sources
PubMed1999

The vast majority of gastric T cells are polarized to produce T helper 1 type cytokines upon antigenic stimulation despite the absence of Helicobacter pylori infection.

Helicobacter pylori infection is associated with chronic infiltration by various cell types, including T cells, whose cytokine production may regulate the inflammatory reaction as well as local immune response to the bacterium. We prospectively analyzed the constituents of the cellular infiltrates and the cytokines produced by T cells in antral biopsies obtained from 73 subjects with and without H. pylori infection, before and after eradication therapy, and compared them with a histological grade of gastritis. We found that T cells predominated in cell number, followed by granulocytes/monocytes and plasma cells in both H. pylori-infected and H. pylori-uninfected subjects. Despite the absence of H. pylori infection, more than 70% of gastric CD4-positive T cells obtained from uninfected tissue produced interferon-gamma (IFN-gamma) in the cytosol. Upon receptor cross-linking of a CD3 and a CD28 molecule, T cells in both infected and uninfected tissue continuously secreted a far greater amount of IFN-gamma than those in peripheral blood mononuclear cell controls for a period of cell culture, whereas the increase in interleukin-4 (IL-4) was very small, and no increase in IL-2 secretion was seen. In H. pylori-infected patients, IFN-gamma secretion was correlated with the grade of mononuclear cell infiltration and decreased to an uninfected control level after eradication therapy. We did not see the effect of eradication on IL-4 secretion. Anti-H. pylori antibody of the IgG2 subclass was remarkably increased in H. pylori-infected subjects. These results together suggest that gastric T cells are already differentiated to produce a large amount of IFN-gamma by a mechanism unrelated to H. pylori infection. H. pylori infection appeared to activate T cells to secrete even more IFN-gamma, which may contribute to maintaining a perpetual inflammation in H. pylori-infected stomach.

Adult↗
PubMed1999

Fate of residual fragments after successful extracorporeal shock wave lithotripsy.

PURPOSE: The aim of the present study was to investigate the reason residual fragments from upper urinary tract calculi failed to clear after successful extracorporeal shock wave lithotripsy (ESWL). METHODS: Risk factors were analyzed in 161 patients with residual fragments (< or = 4 mm) that had remained for more than 3 months after ESWL. The factors examined in the present study were gender, a history of urolithiasis, the number, location and size of stones, hydronephrosis 3 months after ESWL and bacteriuria before ESWL. The mean follow-up period was 20.0 months (range 6-69 months). RESULTS: The overall stone-free rate was 14.3%. The stone-free rate in patients with multiple stones or hydronephrosis 3 months after ESWL was significantly lower than that in patients without these conditions (P < 0.05 and P < 0.01, respectively). The cumulative non-clearance rate in patients with hydronephrosis was significantly higher than in patients without this condition (P < 0.05). Results of Cox's proportional hazards model indicated that hydronephrosis was the most important and only significant factor for failure to clear of the seven factors investigated (P < 0.05). CONCLUSION: Hydronephrosis was most highly correlated with the fate of residual fragments after ESWL.

Adolescent↗
PubMed1999

Relationship between atrioventricular delay, QT interval and cardiac function in patients with implanted DDD pacemakers.

QT interval may change when cardiac function is improved by optimizing the atrioventricular the (AV) delay. The relationship between AV delay, QT interval and cardiac function in patients with implanted DDD pacemakers was studied in 12 patients (aged 71+/-12 SD years) with complete or high degree AV block. Cardiac output (CO) was measured using a Swan-Ganz catheter or by continuous Doppler echocardiography. The pacing rate was fixed at 70-80/min to eliminate the influence of heart rate. The AV delay was prolonged stepwise by 30 ms starting from 90 ms. All measurements were performed after 5 min of pacing. When the AV delay was prolonged, the CO and QT interval gradually increased and reached a peak, and then decreased. When the CO was increased from the minimum to the maximum value by optimizing the AV delay, the QT interval was significantly prolonged from 440+/-40 to 456+/-39 ms (P<0.002). The CO increased from 5.5+/-2.5 to 6.0+/-2.5 l x min(-1) (P<0.002) when the AV delay was changed, during which the QT interval was prolonged from the minimum to the maximum value. There was a significant positive correlation between the optimal AV delay at which CO was maximal (161+/-33 ms) and the optimal AV delay predicted from the maximum QT interval (167+/-29 ms, r=0.85, P<0.001). In conclusion, the optimal AV delay can be predicted from the QT interval.

Adult↗
PubMed1999

Expression profile of active genes in mouse lymph node high endothelial cells.

High endothelial venules (HEV) allow rapid and selective lymphocyte trafficking from the blood into secondary lymphoid tissues. Here we report the expression profile of active genes in mouse high endothelial cells (HEC). HEC were first purified from mouse lymph nodes (LN) by magnetic cell sorting with MECA-79 mAb and a 3'-directed cDNA library that faithfully represents the composition of mRNA was constructed. A total of 1495 cDNA sequences were obtained from randomly selected clones. Based on their sequence identity, they were grouped into 754 different species [gene signatures (GS)] of which 335 GS were identified in GenBank. Among the previously identified genes, expression of several endothelial cell surface molecules including endoglin and ICAM-1 was detected in HEC. Comparison of the gene expression profile with that of purified CD31(+) flat endothelial cells identified several molecules, such as KC chemokine and Duffy antigen/receptor for chemokines, that are known to be selectively expressed in activated endothelial cells or post-capillary venules. Interestingly, mac25/TAF, which is known to be expressed specifically in tumor vessels and implicated in the regulation of cell adhesion, was highly and selectively expressed in HEC in mouse LN, suggesting that it may participate in regulating HEC-specific functions. Comparison with the expression profiles obtained from 35 different cell types showed at least 22 GS that were apparently specific to HEC. Our results illustrate the expression differences between HEC and CD31(+) flat endothelial cells, and will be useful for the identification and characterization of genes specific for HEC.

Animals↗
PubMed1999

Protein phosphatase 2A inhibitors, phoslactomycins. Effects on the cytoskeleton in NIH/3T3 cells.

Protein phosphorylation is a key regulatory mechanism of the organization and dynamics of the actin cytoskeleton during cell motility, differentiation, and cytokinesis. The level of protein phosphorylation is dependent on the relative activities of both protein kinases and protein phosphatases. In this paper, we examined the effect of phoslactomycins (PLMs) on the regulation of the cytoskeleton of NIH/3T3 fibroblasts. Treatment of cells with PLM-F (10 microM) induced actin filament depolymerization after 4 h. This effect was reversible and actin filaments were reformed 1 h after removal of the inhibitors. As PLM-F had no effect at all on polymerization of purified actin in vitro, it is thought that PLMs induce actin depolymerization through an indirect mechanism. An in vitro assay showed PLMs inhibited protein phosphatase 2A at lower concentrations (IC50 4.7 microM) than protein phosphatase 1. An in situ phosphorylation assay also revealed that PLM-F treatment stimulated the phosphorylation of intracellular vimentin. These results suggest that phoslactomycins are protein phosphatase 2A-specific inhibitors and that protein phosphatase 2A is involved in regulation of the organization of the actin cytoskeleton.

3T3 Cells↗
PubMed1999

Prediction of optimal atrioventricular delay in patients with implanted DDD pacemakers.

In patients with an implanted DDD pacemaker (PM), the atrial contribution may be interrupted by too short an atrioventricular (AV) delay, and filling time may be shortened by too long an AV delay. The AV delay at which the end of the A wave on transmitral flow coincides with complete closure of the mitral valve may be optimal. The subjects were 15 patients [70.3+/-12.3 (SD) years old] with an implanted DDD PM. Cardiac output (CO) and pulmonary capillary wedge pressure (PCWP) were measured by Swan-Ganz catheter. Transmitral flow was recorded by pulsed Doppler echocardiography. AV delay was prolonged stepwise by 25 msc. When the AV delay was set at 155+/-26 ms, the end of the A wave coincided with complete closure of the mitral valve. When the AV delay was prolonged 25, 50, 75, and 100 ms from this AV delay, the interval between the end of the A wave and complete closure of mitral the valve was prolonged 16+/-5, 39+/-6, 65+/-4 and 88+/-5 ms, respectively (r = 0.97, P<0.0001) and diastolic mitral regurgitation was observed during this period. Thus, the optimal AV delay may be predicted as follows: the slightly prolonged AV delay minus the interval between the end of the A wave and complete closure of the mitral valve. When the AV delay was set at 215 ms, there was a significant positive correlation between the predicted optimal AV delay (166+/-23 ms) and the optimal AV delay (CO: 161+/-26 msec, r = 0.93, P<0.0001, PCWP: 161+/-28 msec, r = 0.95, P<0.0001). In conclusion, optimal AV delay can be predicted by this simple formula: slightly prolonged AV delay minus the interval between end of A wave and complete closure of mitral valve at the AV delay setting.

Aged↗
PubMed1999

Cloning and characterization of a novel membrane-associated antigenic protein of Helicobacter pylori.

Infection by Helicobacter pylori, a noninvasive bacterium, induces chronic leukocyte infiltration in the stomach by still largely unknown molecular mechanisms. We investigated the possibility that a membrane protein of H. pylori induces an inflammatory reaction in the subepithelial tissue of the stomach. By generating an expression library of H. pylori chromosomal DNA and screening with rabbit antiserum raised to a membrane fraction of H. pylori and sera of infected patients, we cloned a 16.0-kDa protein (HP-MP1) which appeared to attach to the inner membrane of the H. pylori in a homodimeric form. Anti-HP-MP1 antibodies were detected in the sera of infected patients but not in those of uninfected controls. Coincubation of monocytes with recombinant HP-MP1 led to cell activation and production of interleukin-1alpha (IL-1alpha), tumor necrosis factor alpha, IL-8, and macrophage inflammatory protein 1alpha. The results indicate that HP-MP1 is an antigenic membrane-associated protein of H. pylori which potentially activates monocytes. This suggests that HP-MP1 may play roles in the pathogenesis of perpetual tissue inflammation associated with H. pylori infection.

Antibodies, Bacterial↗
PubMed1999

Characterization of Prophet of Pit-1 gene expression in normal pituitary and pituitary adenomas in humans.

Prophet of Pit-1 (Prop-1), which is a paired-like homeodomain transcription factor, is capable of binding to sites in an early enhancer of the Pit-1 gene and regulating its expression. According to a previous report, Prop-1 messenger RNA (mRNA) is expressed in the developing pituitary gland before Pit-1 mRNA expression and maximum expression are observed at e 12.0. After e 14.5, Prop-1 mRNA expression rapidly decreases, and only trace amounts of mRNA are detectable in adult mouse pituitary. Human Pit-1 is expressed considerably, not only in normal adult pituitary but also in pituitary adenomas, so we studied human Prop-1 gene expression in adult pituitary and pituitary adenomas. We also cloned human Prop-1 complementary DNA (cDNA) and sequenced the Prop-1 cDNAs in pituitary adenomas. The amino acid sequence of human Prop-1 cDNA that we cloned was identical to that of the previously reported sequence, except Thr substituted at codon 142 instead of Ala. This amino acid substitution is considered to be a polymorphism because it did not alter transcriptional activity, and 7 of 28 alleles were Ala. Human Prop-1 transcript was detected in normal adult pituitary, by Northern blot analysis, and in all pituitary adenomas examined by RT-PCR analysis. The expression of human Prop-1 in pituitary adenomas was confirmed by in situ hybridization in one of the somatotroph adenomas. The sequence analysis of human Prop-1 cDNAs in these pituitary adenomas revealed that there were no mutations, except 5 silent nucleic acid substitutions, suggesting that mutations of Prop-1 gene do not represent a frequent mechanism of human pituitary tumorigenesis.

Adenoma↗
PubMed1999

[Usefulness of urethral descent for evaluating the type of female stress urinary incontinence].

BACKGROUND: To select suitable treatment for stress urinary incontinence (SUI), both urethral function and urethral mobility must be assessed. Abdominal leak point pressure (ALPP) is considered to be useful to evaluate urethral function, and radiographic findings are effective to evaluate urethral mobility. However no adequate methods to measure urethral mobility with videourodynamics study (VUDS) exist. We measured the downward movement of the membranous urethra at the same time as ALPP was measured on VUDS, and examined whether or not the urethral descent on VUDS is useful to evaluate urethral mobility. METHODS: The subjects were 28 women with over grade II SUI (according to McGuire's grading) who underwent bead chain cystography and VUDS. As a classical index of urethral mobility, we measured the change of posterior urethrovesical angle (PUVA) and vesical neck descent during Valsalva maneuver on bead chain cystography. The videourodynamic urethral catheter had a radiographic marker that permitted the identification of the location of the urethral pressure sensing aperture. The catheter was fixed at the position where the urethral pressure aperture reached the point of highest pressure. The urethral descent was defined as the downward movement of the urethral marker during Valsalva maneuver while measuring ALPP. According to the urethral descent the patients were classified as follows: 1) hyper-mobile group; urethral descent was over 5 mm. 2) non-mobile group: urethral descent was under 5 mm. The severity of SUI was evaluated with 1 hr. pad weighting test, ALPP and maximum urethral pressure. RESULTS: The urethral descent was significantly related to vesical neck descent and PUVA change. In the non-mobile group (11 cases), ALPP was significantly lower, and urine loss on the pad weighting test was significantly greater than that in the hyper-mobile group (17 cases). The non-mobile group exhibited more severe incontinence than the hyper-mobile group. When the patients were classified according to Blaivas's classification, all patients in type III and 2 in type I were in the non-mobile group. These 2 type I patients had low ALPP (40 cm. water and 70 cm. water) and a history of radical hysterectomy. Therefore these patients were diagnosed with ISD due to the fixed urethra. CONCLUSIONS: Urethral descent is an useful index of urethral mobility. In the non-mobile group, the pathophysiological cause of SUI was not urethral hypermobility but ISD, and it was diagnosed as type III SUI without urethral mobility. We consider that urethral descent assesses urethral mobility more accurately than vesical neck descent, and that urethral descent is a valuable parameter on VUDS.

Adult↗
PubMed1999

[Clinical statistics of stage I testicular tumor].

PURPOSE: A survey of stage I testicular tumors in the Chugoku-Shikoku district was taken in order to explore the clinical characteristics. PATIENTS AND METHODS: Three hundred and forty eight cases of stage I testicular tumor treated at 46 facilities in the Chugoku-Shikoku district between 1984 and 1992 were collected. Subjects' background factors, treatment methods and prognosis were studied. RESULTS: Tissue types were 249 (71.6%) seminoma and 99 (28.4%) non-seminoma. Adjuvant therapy for seminoma cases included 138 post-operative radiotherapy (4 recurrences, 3 cancer deaths), 57 chemotherapy (no recurrences, 2 contralateral testis tumor cases) and 48 were under surveillance (no recurrence). Adjuvant therapy for non-seminoma cases included 47 chemotherapy (1 recurrence) and retroperitoneal lymph node dissection was performed on 6 cases. Forty cases were under surveillance (1 recurrence). Of 8 (2.3%) cases with recurrence, 6 showed onset within two years and 2 after two years. Four of the 8 cases with recurrence were seminoma (1.1% of seminoma cases) and the other 4 were non-seminoma (4.0% of non-seminoma cases). All 3 (0.9% of all cases) of the cancer death cases were seminoma that received post-operative radiotherapy, while there were no cancer deaths in non-seminoma cases. CONCLUSION: Prognosis of stage I testicular tumor is good. Although the recurrence rate was higher in non-seminoma cases, cancer deaths were only observed in seminoma cases.

Adolescent↗
PubMed1999

Hyaluronan synthase expression in bovine eyes.

PURPOSE: Hyaluronan (HA), a high-molecular-weight linear glycosaminoglycan, is a component of the extracellular matrix (ECM). It is expressed in eyes and plays important roles in many biologic processes, including cell migration, proliferation, and differentiation. Hyaluronan is produced by HA synthase (HAS), which has three isoforms: HAS1, HAS2, and HAS3. In this study, the HAS expression in the anterior segment of bovine eyes was investigated to determine the significance of HA in eyes. METHODS: To obtain bovine HAS probes, degenerate oligonucleotide primers, based on well-conserved amino acid sequences including the catalytic region of each HAS isoform, were used for reverse transcription-polymerase chain reaction to amplify mRNA from bovine corneal endothelial cells (BCECs). Hyaluronan synthase-1 expression in the anterior segment of bovine eyes at the protein level was investigated by immunohistochemistry. RESULTS: All three HAS isoforms were expressed in BCECs at the mRNA level. Amplified cDNA fragments of HAS1, HAS2, and HAS3 from BCECs can be aligned to human counterparts, showing similarities of 100%, 97.3%, and 100%, respectively, at the amino acid level. Hyaluronan synthase 1 was expressed at the protein level in corneal epithelium, keratocyte, corneal endothelium, conjunctival epithelium, ciliary epithelium, capillary endothelium, and trabecular meshwork. CONCLUSIONS: Hyaluronan synthase isoforms were expressed in the ocular anterior segment and are speculated to be involved in HA production in situ.

Amino Acid Sequence↗
PubMed1999

Cone signal contributions to electroretinograms [correction of electrograms] in dichromats and trichromats.

PURPOSE: To find out how the different cone types contribute to the electroretinogram (ERG) by quantifying the contribution of the signal pathways originating in the long (L-) and the middle (M-) wavelength-sensitive cones to the total ERG response amplitude and phase. METHODS: ERG response amplitudes and phases were measured to cone-isolating stimuli and to different combinations of L- and M-cone modulation. Conditions were chosen to exclude any contribution of the short wavelength-sensitive (S-) cones. The sensitivity of the ERG to the L and the M cones was defined as the cone contrast gain. RESULTS: In the present paper, a model is provided that describes the ERG contrast gains and ERG thresholds in dichromats and color normal trichromats. For the X-chromosome-linked dichromats, the contrast gains of only one cone type (either the L or the M cones) sufficed to describe the ERG thresholds for all stimulus conditions. Data suggest that the M-cone contrast gains of protanopes are larger than the L-cone contrast gains of deuteranopes. The response thresholds of the trichromats are modeled by assuming a vector summation of signals originating in the L and the M cones. Their L- and M-cone contrast gains are close to a linear interpolation of the data obtained from the dichromats. Nearly all trichromats had larger L- than M-cone contrast gains. Data from a large population of trichromats were examined to study the individual variations in cone weightings and in the phases of the cone pathway responses. CONCLUSIONS: The data strongly suggest that the missing cone type in dichromats is replaced by the remaining cone type. The mean L-cone to M-cone weighting ratio in trichromats was found to be approximately 4:1. But there is a substantial interindividual variability between trichromats. The response phases of the L- and the M-cone pathways can be reliably quantified using the response phases to the cone-isolating stimuli or using a vector addition of L- and M-cone signals.

Adolescent↗
PubMed1999

[Anesthetic management of a patient with psoriasis arthropathica].

A 37-year-old woman with psoriasis arthropathica associated with aortic regurgitation underwent replacement of her aortic valve. The serum rheumatic factor was negative. HLA-B 27 was demonstrated in HLA analysis. She experienced a sudden onset of dyspnea and cardiac arrest in the hospital. She was hospitalized and found to have severe aortic regurgitation. She had her aortic valve replaced. We paid attention to management of blood pressure not to trigger cardiac ischemia and of skin lesion not to trigger infection and the worsening of skin condition. There are few reports of HLA-B 27 positive psoriasis arthropathica accompanied by aortic regurgitation. However, the present case may suggest that the cardiac study may be required for HLA-B 27 positive psoriasis arthropathica.

Adult↗
PubMed1998

Complex formation and functional versatility of Mre11 of budding yeast in recombination.

Meiotic recombination of S. cerevisiae contains two temporally coupled processes, formation and processing of double-strand breaks (DSBs). Mre11 forms a complex with Rad50 and Xrs2, acting as the binding core, and participates in DSB processing. Although these proteins are also involved in DSB formation, Mre11 is not necessarily holding them. The C-terminal region of Mre11 is required only for DSB formation and binds to some meiotic proteins. The N-terminal half specifies nuclease activities that are collectively required for DSB processing. Mre11 has a DNA-binding site for DSB formation and another site for DSB processing. It has two regions to bind to Rad50. Mre11 repairs methyl methanesulfonate-induced DSBs by reactions that require the nuclease activities and those that do not.

Animals↗
PubMed1998

Lysophosphatidylcholine upregulates CD40 ligand expression in newly activated human CD4+ T cells.

Lysophosphatidylcholine (lyso-PC) accumulates in tissues undergoing inflammation and atherosclerosis, where an infiltration of T cells is also seen. We found that lyso-PC increased IFN-gamma production and CD40L expression in CD4+ T cells stimulated with anti-CD3 Ab and recombinant CD80 molecules, whereas lyso-PC did not affect IL-2 and IL-4 production. These results suggest that lyso-PC, in combination with other stimuli, may regulate CD4+ T cell functions to propagate local inflammatory reactions and also imply a novel role played by a modified lipid in the selection of Th1/Th2 immune response as well as in the T cell mediated pathogenesis in atherosclerosis.

Antibodies↗
PubMed1998

Tryprostatin A, a specific and novel inhibitor of microtubule assembly.

We have investigated the cell cycle inhibition mechanism and primary target of tryprostatin A (TPS-A) purified from Aspergillus fumigatus. TPS-A inhibited cell cycle progression of asynchronously cultured 3Y1 cells in the M phase in a dose- and time-dependent manner. In contrast, TPS-B (the demethoxy analogue of TPS-A) showed cell-cycle non-specific inhibition on cell growth even though it inhibited cell growth at lower concentrations than TPS-A. TPS-A treatment induced the reversible disruption of the cytoplasmic microtubules of 3Y1 cells as observed by indirect immunofluorescence microscopy in the range of concentrations that specifically inhibited M-phase progression. TPS-A inhibited the assembly in vitro of microtubules purified from bovine brains (40% inhibition at 250 microM); however, there was little or no effect on the self-assembly of purified tubulin when polymerization was induced by glutamate even at 250 microM TPS-A. TPS-A did not inhibit assembly promoted by taxol or by digestion of the C-terminal domain of tubulin. However, TPS-A blocked the tubulin assembly induced by inducers interacting with the C-terminal domain, microtubule-associated protein 2 (MAP2), tau and poly-(l-lysine). These results indicate that TPS-A is a novel inhibitor of MAP-dependent microtubule assembly and, through the disruption of the microtubule spindle, specifically inhibits cell cycle progression at the M phase.

Animals↗
PubMed1998

Cell cycle arrest and antitumor activity of pironetin and its derivatives.

The biological effects of pironetin and its derivatives on cell cycle progression and antitumor activity were studied. At 10-20 ng/ml, both pironetin and its demethyl derivative, NK10958P completely inhibited the cell proliferation of 3Y1 cells, however, epoxypironetin showed only a weak inhibitory activity. The cell cycle analysis revealed that these compounds arrested the cell cycle progression at the M-phase in a dose-dependent manner. These antiproliferative effects of pironetin were also observed in the range 5-25 ng/ml with several tumor cell lines. In CDF1-SLC mice bearing P388 leukemia cells, the intraperitoneal administration of 6.3 mg/kg pironetin over a 5-day period showed a moderate antitumor effect (T/C, 128%). As the chemical structure of pironetin is different from other M-phase inhibitors such as colchicine or vinblastine, pironetin will be the lead compound for a potential new antitumor drug.

Animals↗