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T Shigematsu

Publications and source records attributed to T Shigematsu.

At least 19 recordsLinked to original sources
PubMed1997

Dissection of the promoter/operator region and evaluation of N-acylhomoserine lactone mediated transcriptional regulation of elastase expression in Pseudomonas aeruginosa.

In Pseudomonas aeruginosa, expression of the lasB gene which codes for the metalloprotease, elastase, depends on small diffusible N-acylhomoserine lactones. lasB expression is regulated through the interactions of N-3-oxododecanoyl-L-homoserine lactone and N-butanoyl-L-homoserine lactone with the transcriptional activators LasR and VsmR(RhlR), respectively. To investigate lasB expression further, we first located the transcriptional start site to a position 141 bp upstream from the translational start site. Using this information, we constructed a series of plasmids containing consecutive 5' deletions of the upstream region of lasB fused to a promoterless chloramphenicol acetyltransferase reporter gene. The results obtained indicate that three regions are required for efficient transcription of lasB; a 35 bp palindromic sequence located at +26 to +60 bp upstream from the translation start site, and two regions located upstream of the transcription start site, at -135 to -85 bp and -63 to -26 bp, respectively. Deletion of the latter region results in the loss of both N-butanoyl-L-homoserine lactone- and N-3-oxododecanoyl-L-homoserine lactone-mediated stimulation of lasB expression and provides further support for the role of this operator site as a target for either or both LasR and VsmR.

Bacterial Proteins↗
PubMed1997

Adenocarcinoma of the uterine cervix with predominantly villogladular papillary growth pattern.

We reviewed the clinical and pathological features of seven cases of adenocarcinoma of the uterine cervix with predominantly villogladular papillary growth pattern. The patients, who ranged in age from 33 to 54 (mean, 45) years, underwent radical hysterectomy. In all seven cases, the tumors were papillary exophytic architecture lined by stratified epithelial cells with mild to moderate nuclear atypicality. In one of seven cases, the majority of the tumor showed villogladular papillary component, but the small foci of small cell carcinoma was present in the endocervical end of the tumor. The lymph vascular invasion was demonstrated in two of seven cases, and these two had pelvic lymph node metastases. One of these two patients had recurrence 30 months after the initial treatment and died of disease after 46 months. The follow-up ranged from 9 to 169 (median, 46) months. The presence or absence of lymph vascular invasion and minor components of this tumor such as small cell carcinoma, serous cell carcinoma, and clear cell carcinoma with a poor prognosis may be important histological findings before deciding to manage this tumor by the conservative treatment.

Adenocarcinoma↗
PubMed1997

Immunohistochemical detection of advanced glycosylation end-products in the peritoneum and its possible pathophysiological role in CAPD.

It has recently been suggested that advanced glycosylation end-products (AGEs) are formed in the peritoneum in patients on CAPD. However, the exact location of AGE accumulation, the relation with the duration of CAPD and its pathophysiological role in CAPD remain unclear. If the peritoneum is glycosylated, it could bring about altered peritoneal function. Therefore, the aim of this study is to clarify the localization of AGEs in the peritoneum in accordance with the duration of CAPD and to examine its relation to the peritoneal permeability. Fifteen non-diabetic patients were divided into three groups (each 5 patients) on the basis of the mean duration (D) of CAPD (Group 1, D = 0 month; Group II, D = 34 months; Group III, D = 84 months). The AGE staining by monoclonal anti-AGE antibody in the peritoneum and the four-hour peritoneal equilibration test (PET) were compared among these groups. AGE was absent or found only weakly in Group I. However, in groups II and III, AGE was moderately or strongly positive especially in the vascular walls and it was dominant in group III. PET revealed that peritoneal permeability for glucose, creatinine, beta2-microglobulin and albumin was increased in Group II as compared to Group I, and it was further increased in Group III. The results of this study indicate that AGEs become dominantly accumulated in the vascular wall in accordance with the prolongation of CAPD treatment, and this might play some roles for the increased permeability of the peritoneal membrane in CAPD.

Adult↗
PubMed1997

Enhanced lymphocyte interaction in postcapillary venules of Peyer's patches during fat absorption in rats.

BACKGROUND & AIMS: Although dietary fat is known to modulate immune functions, there is a paucity of data concerning the effects of fat absorption on migration of lymphocytes in intestinal lymphoid tissue. The objective of this study was to assess the influence of fat absorption on T-lymphocyte migration in Peyer's patches. METHODS: T lymphocytes collected from rat intestinal lymph were labeled with carboxyfluorescein diacetate succinimidyl ester and injected into the jugular vein of recipient rats. Olive oil or octanoic acid was placed into the duodenum, and Peyer's patch microcirculation was observed by intravital fluorescence microscopy. RESULTS: Rolling and adherence of lymphocytes in postcapillary venules were noted in both fasted and fed rats. However, lymphocyte adherence was significantly greater in olive oil-fed rats than in fasted rats. Olive oil also significantly increased the transendothelial migration of T lymphocytes. Octanoic acid stimulated lymphocyte rolling but did not affect lymphocyte adherence. Olive oil enhanced the expression of both alpha4-integrin and L-selectin on lymphocytes, whereas octanoic acid only increased the expression of L-selectin. CONCLUSIONS: Lymphocyte rolling and adherence are enhanced by olive oil feeding, possibly through an interaction between activated adhesion molecules on lymphocytes and counter-receptors on endothelial cells.

Animals↗
PubMed1997

Vasoactive intestinal peptide modulates T lymphocyte migration in Peyer's patches of rat small intestine.

Although vasoactive intestinal peptide (VIP) has been postulated to function in modulation of T cell trafficking, the exact mechanism has not been elucidated in vivo. In the present study, the effects of VIP on T lymphocyte migration were examined in rat Peyer's patches. T lymphocytes collected from intestinal lymph of rats were labeled with carboxyfluorescein diacetate succinimidyl ester and injected into the jugular vein. Peyer's patches of the recipient rats were observed with intravital fluorescence microscopy. In vivo intra-arterial infusion of or in vitro incubation with VIP did not affect the initial lymphocyte interaction with postcapillary venules of Peyer's patches. However, these treatments with VIP significantly inhibited transendothelial migration and also significantly blocked the interstitial migration of T cells and inhibited their subsequent appearance in the interfollicular lymphatics. Treatment with adenosine 3',5'-cyclic monophosphate (cAMP)-inducing agents resulted in similar inhibitory effect on T lymphocyte migration in Peyer's patches. In conclusion, VIP has significant inhibitory effects on T lymphocyte migration in Peyer's patches, possibly mediated by elevation of the intracellular cAMP concentrations.

Animals↗
PubMed1996

Cloning, sequencing and transcriptional regulation of the draT and draG genes of Azospirillum lipoferum FS.

From Azospirillum lipoferum (Al) FS, a nitrogen-fixing bacterium isolated from the rhizosphere of rice, we cloned and sequenced draT, encoding dinitrogenase reductase ADP-ribosyltransferase, and draG, encoding dinitrogenase reductase-activating glycohydrolase. The nucleotide sequences of draTG showed extensive similarity to the same genes from Azospirillum brasilense, Rhodospirillum rubrum and Rhodobacter capsulatus, and they are assumed to be co-transcribed as a single operon. When this draTG operon was introduced into Klebsiella oxytoca, this organism acquired the ability to respond to extracellular NH(+4) ions with reversible inhibition of nitrogenase activity, similar to that seen in Al FS. We constructed a plasmid containing a draT::lacZ gene fusion and found that beta-galactosidase activity was detected under microaerobic conditions, regardless of NH(+4) concentration, but not under aerobic conditions. This indicates that the transcription of draTG responds to the level of oxygen, but not to that of NH(+4) ions.

ADP Ribose Transferases↗
PubMed1996

alpha 4 integrin plays a critical role in early stages of T lymphocyte migration in Peyer's patches of rats.

Lymphocyte recirculation through the blood flow circuit and lymphoid organs is important for the maintenance of immune defense, and is defined as lymphocyte homing. During the homing process, several adhesion molecules have been postulated to play an important role in lymphocyte recruitment from the vascular space. In the present study, we investigated the effect of a novel mAb against rat alpha 4 integrin (MR alpha 4-1) on the interaction of T lymphocytes with postcapillary venules (PCV) and their subsequent migration into the interstitium of Peyer's patches, using intravital video microscopy. T lymphocytes collected from intestinal lymph were labeled with a fluorochrome carboxyfluorescein diacetate succinimidyl ester and were than injected into the jugular vein of recipient rats. The microvasculature in the ileal Peyer's patches of recipient rats was observed sequentially by intravital fluorescence microscopy. In controls, lymphocytes exhibited rolling behavior which was followed by firm adhesion to the endothelium of PCV. The density of sticking lymphocytes gradually increased during the first 30 min. These initial interactions of lymphocytes with the PCV (rolling and adherence) were drastically inhibited by treatment with MR alpha 4-1, both when MR alpha 4-1 was preinfused into rats and when T cells were preincubated in vitro with MR alpha 4-1 before administration. MR alpha 4-1 also significantly inhibited the transendothelial migration of T lymphocytes, associated by the ratio of migration to adherence. However, once T lymphocytes migrated into the interstitium, treatment with MR alpha 4-1 did not affect the pattern of travel of these lymphocytes in the interstitium or their transport into the microlymphatics in the parafollicular area. Therefore, we conclude that alpha 4 integrins play a critical role in the rolling and sticking of T cells and their transendothelial migration in PCV of Peyer's patches.

Animals↗
PubMed1996

Effect of chronic ethanol feeding on nitric oxide synthesis by rat Kupffer cells.

Kupffer cells contribute to the important role of the liver defense mechanism through nitric oxide (NO) production. In this study, the effect of chronic ethanol administration on the ability of Kupffer cells to synthesize and release NO was investigated after stimulation with lipopolysaccharide (LPS). Male Wistar rats were chronically fed ethanol for 8 weeks according to the method described by DeCarli and Lieber et al. (J Nutr.91:331-336, 1967). Kupffer cells were isolated and cultured with LPS (1 micrograms/ml) for 24 hr. The levels of nitrite and nitrate, metabolites of NO, were determined in the culture medium, NO synthase (NOS) activity in Kupffer cells was determined by the method that measures conversion of [14C]arginine into [14C]citrulline. In control rats, a significant increase of nitrite and nitrate levels in culture medium was observed after LPS treatment. The magnitude of this increase was significantly smaller in chronic ethanol-fed rats. When the activity of NOS was determined, inducible NOS (iNOS) activity was higher than that of constitutive NOS, and LPS administration produced a significant elevation of iNOS activity in both control and chronic ethanol-fed rats. However, the elevation of iNOS activity by LPS stimulation was diminished by chronic ethanol administration. Distribution of iNOS in Kupffer cells as determined by an immunofluorescence method using a laser scanning confocal image system showed a lower expression of iNOS in chronic ethanol-fed rats even in the presence of LPS. These results demonstrate that the excessive production of NO by increased iNOS activity in Kupffer cells is diminished by chronic ethanol administration.

Animals↗
PubMed1996

Clear cell odontogenic carcinoma in the mandible: histochemical and immunohistochemical observations with a review of the literature.

A rare case of clear cell odontogenic carcinoma was investigated using histochemical and immunohistochemical methods. The tumor occurred in the anterior mandible of a 69-year-old Japanese man. Histologically, the tumor was composed mostly of large clear cells and squamous cells. Columnar-shaped cells with basophilic nuclei polarized away from the basement membrane were observed at the periphery of the tumor foci. The tumor cells had aggressively invaded muscle and perineural tissues. The tumor cells were positive for PAS staining. Immunohistochemically, tumor cells reacted positively to keratin, cytokeratin19, epithelial membrane antigen, and S-100 protein. The tumor was diagnosed as a clear cell odontogenic carcinoma. Its characteristics are discussed in term of its histopathological, histochemical and immunohistochemical features.

Aged↗
PubMed1996

Endotoxin stimulates lymphocyte-endothelial interactions in rat intestinal Peyer's patches and villus mucosa.

Although lymphocyte-endothelial cell interactions represent a key step in controlling the recruitment of lymphocytes into gut-associated tissues, its dynamic process in microvessels of lymphoid (Peyer's patches) and nonlymphoid (villus) regions of the small bowel remains poorly understood. We monitored the migration of fluorescence-labeled T lymphocytes into normal and lipopolysaccharide (LPS)-inflamed rat intestinal microvessels using intravital microscopy. In Peyer's patches, T lymphocytes selectively adhered to postcapillary venules, although such selectivity was not observed in submucosal venules of villi. T lymphocytes exhibited rolling behavior followed by firm adhesion in microvessels of both the Peyer's patches and the villi, with both types of adhesive interaction being mediated by alpha 4-integrins. The enhanced rolling and adherence of lymphocytes observed in Peyer's patches and submucosal venules of villi of LPS-treated rats were preceded by a reduction in shear rate and were mediated largely by alpha 4-integrins and partly by beta 2-integrins. In capillaries of intestinal mucosa, lymphocyte adherence occurred without rolling and was independent of alpha 4-integrins. LPS also significantly increased adherence of lymphocytes to villus capillaries, which was not mediated by either alpha 4- or beta 2-integrin. These observations demonstrate significant heterogeneity of lymphocyte-endothelial cell interactions within different regions of the intestinal mucosa.

Animals↗
PubMed1996

Roles of ET-1 in endotoxin-induced microcirculatory disturbance in rat small intestine.

The major objective of this study was to investigate whether endothelin-1 (ET-1) plays a significant role in endotoxin-induced microcirculatory disturbances of the intestinal mucosa. Submucosal microvessels of the rat ileum were observed by intravital microscopy with a high-speed video camera system. Preceding the apparent intestinal mucosal damage, red blood cell (RBC) velocity was significantly decreased 30 min after endotoxin treatment in both arterioles and venules. The number of leukocytes sticking to submucosal venules was significantly increased at 30 min. BQ-123, an ETA-receptor antagonist, significantly attenuated the decrease in RBC velocity and also prevented an increase in leukocyte sticking as well as the subsequent mucosal damage induced by endotoxin. The ET-1 concentrations began to be elevated in plasma at 15 min and in the mucosa at 30 min and subsequently further increased in a time-dependent manner. A significant decrease in calcium-dependent nitric oxide synthase activity and significant increases in the concentration of platelet-activating factor (PAF) were demonstrated in the intestinal mucosa after endotoxin treatment. BQ-123 also significantly attenuated these changes. We concluded that the increased ET-1 production in intestinal mucosa induced by endotoxin stimulation could lead to leukocyte sticking and decreased RBC velocity in the intestinal microcirculatory beds via ETA receptors, which are closely related to increased production of PAF and decreased synthesis of constitutive nitric oxide.

Animals↗
PubMed1996

A rare case of idiopathic hypoparathyroidism with varied neurological manifestations.

A 47-year-old man was admitted for evaluation of unsteady gait, postural instability, and dysarthria. On admission, neurological examinations revealed cerebellar ataxia, extrapyramidal signs including parkinsonism and positive Trousseau's sign. Laboratory findings revealed severe hypocalcemia and hyperphosphatemia, and serum intact parathyroid hormone was not detectable. Brain computed tomography revealed severe calcification of basal ganglia and dentate nuclei. He was diagnosed as idiopathic hypoparathyroidism; treatment with 1 alpha (OH) vitamin D3 brought marked improvement of neurological manifestations. We report a rare case of idiopathic hypoparathyroidism presenting with extrapyramidal and cerebellar dysfunction with a review of literature.

Basal Ganglia↗
PubMed1996

The effect of ultra-low sodium dialysate in CAPD. A kinetic and clinical analysis.

In peritoneal dialysis, sodium (Na) passes through the peritoneal membrane to a lesser extent than H2O and thus hypotonic fluid is removed indicating that Na removal is inefficient. Therefore we developed an ultra-low Na dialysate (ULNaD) [Na 98 mmol/liter, osmolality 340 mOsm/kg, glucose (G), 2.48%] to facilitate trans-peritoneal Na removal. The aim of the study was to examine (a) the fluid and Na kinetics of this solution, and (b) the clinical effect in the overhydrated patient. Regarding the former, in six cases, changes in the effluent Na levels during a 240-minute dwell of ULNaD were measured at 60-minute intervals. In eighteen cases, the transperitoneal net-Na removal (Na removal) and drained ultrafiltration (UF) volume after a 240-minute dwell of ULNaD were measured and compared to two types of standard Na dialysate (SNaD) [Na 132 mmol/liter, 1.36% G (348 mOsm/kg) and 2.27% G (396 mOsm/kg)]. The effluent Na levels increased gradually until the end of the dwelling. Drained UF volume of ULNaD (224 +/- 25 ml) was more than 1.36% G SNaD (77 +/- 33 ml, p < 0.01), but it was less than 2.27% G SNaD (341 +/- 32 ml, p < 0.01). However, a significant increase in Na removal by ULNaD (78.1 +/- 5.6 mmol) was found compared with both SNaD solutions (12.6 +/- 6.4 mmol in 1.36% G solution, p < 0.001; 27.8 +/- 5.1 mmol in 2.27% G solution, p < 0.001, respectively). Regarding the latter study aim, in six overhydrated patients with a Na excess, SNaD was replaced with ULNaD once a day for 7 consecutive days. At the end of the study as compared to the pre-values, a significant reduction in body weight (-2.5 +/- 1.0%, p < 0.05) and mean arterial pressure (-12.3 +/- 3.5%, p < 0.001) was observed. An increased drainage of daily UF volume (+86.5 +/- 31.1%, p < 0.05) and a markedly increased daily Na removal (+131.1 +/- 24.2%, p < 0.01) were also observed. The results of this study suggest that ULNaD actually facilitates trans-peritoneal Na removal mainly by diffusion force, and that ULNaD could benefit overhydrated patients with a Na excess.

Adult↗
PubMed1996

Is atherosclerosis accelerated by CAPD?

Cardiovascular complications in renal replacement therapy remain prevalent today. The question, "Is atherosclerosis accelerated in peritoneal dialysis (PD) patients," has not been resolved. Many cross-sectional studies have revealed that there are more atherogenic lipid profiles in continuous ambulatory peritoneal dialysis (CAPD) than in other dialytic modalities. However, it is not certain that CAPD per se may contribute to lipid abnormalities in continuing PD for a long time. Therefore, we tried to assess whether CAPD itself may change lipid profiles in the long-term period on CAPD. We measured conventional lipid profiles in 16 stable CAPD patients in whom total cholesterol (T.chol.) levels remained under 240 mg/dL at the time of starting observation. Diabetic end-stage renal disease (DMESRD) patients were excluded from this study. Blood sampling was performed under strict conditions indicating overnight fasting with 10 hours dwell of 2 L of 1.5% Dianeal. Plasma levels of T.chol., triglyceride, high-density lipoprotein (HDL), low-density lipoprotein (LDL), and atherogenic lipoprotein (apo B/A-I) did not show significant changes by serial measurements from the sixth month to the thirtieth month following the commencement of CAPD as their initial dialysis treatment. Recently it is reported that high plasma levels of Lp(a) lipoprotein are an independent risk factor in cardiovascular events in renal replacement therapy because Lp(a) has a close relation to intravascular thrombosis and acceleration of atherosclerosis. We found that the incident of vascular accidents was five episodes among 33 patients with higher (> 31 mg/dL) Lp(a) levels, while there was only one episode in 45 patients with lower (< 30 mg/dL) Lp(a) levels (p < 0.05, odds ratio: 7.9). However, severity of aortic calcification and incidence of positive treadmill test showed no difference in these two groups. No significant correlation was observed between duration on CAPD and plasma Lp(a) levels. From the fact mentioned above, we speculate that CAPD does not essentially affect lipid profiles if determined under the strict condition of blood sampling. In order to evaluate the atherosclerosis noninvasively, we have measured aortic pulse wave velocity (AoPWV) in 33 stable CAPD patients excluding those with DMESRD by two years' interval. Fifteen cases (46%) increased in AoPWV, however, lipid profiles did not differ from those of nonadvanced patients. Calcification of arteries is further evidence of acceleration in atherosclerotic change. Therefore, we have graded severity of abdominal aortic calcification into three categories: grade I denoted nil calcification, grade II denoted patchy calcification, and grade III denoted calcification along the entire abdominal wall, having a lead-pipe shape by lateral view of plain abdominal x-ray film. There were significant differences in the duration of CAPD (grade I: 41 months, grade II: 60 months, grade III: 68 months). AoPWV showed least in the grade I group, faster in grade II, and fastest in grade III, while lipid profiles did not show significant differences in three categories. From the analysis of serial changes of lipid profiles, AoPWV and aortic calcification, CAPD may present some risk of accelerating atherosclerosis, at least in some patients on long-term treatment. Risk factors contributing to acceleration of atherosclerosis is result not from lipid abnormalities, but from other factors which remained to be seen, for example, abnormalities in calcium metabolism.

Adult↗
PubMed1996

Low calcium (1.25 mmol/L) dialysate can normalize relative hypoparathyroidism in CAPD patients with low bone turnover.

Recently, several reports have suggested that there is a higher incidence of low turnover bone in the absence of aluminium exposure in peritoneal dialysis patients than in hemodialysis patients. Relative hypoparathyroidism with mild hypercalcemia, induced by a positive calcium balance, is considered to be one of the major causes of this disorder. Thus, we recruited 9 continuous ambulatory peritoneal dialysis (CAPD) patients with relative hypoparathyroidism and low bone turnover [intact parathyroid hormone (iPTH) < 50 pg/mL, intact osteocalcin < 10.0 ng/mL] who had been prescribed 1.75 mmol/L calcium (Ca) dialysate for 5.0 +/- 0.3 years. They were then treated by low Ca (1.25 mmol/L) dialysate for nine months without vitamin D and aluminum administration. Intact PTH and bone metabolic markers [intact osteocalcin, alkaline phosphatase (ALP)] were measured every three months. Intact PTH levels increased from 21.1 +/- 3.8 to 159.2 +/- 32.8 pg/mL after the first three months; thereafter, those levels were maintained at around 150 pg/mL. On the other hand, intact osteocalcin levels rose consecutively from 6.7 +/- 1.2 to reach 22.0 +/- 3.8 ng/mL after nine months. Interestingly, the pattern of time course changes between PTH and intact osteocalcin was different. ALP activity did not change during the nine-month period. Corrected serum calcium was significantly decreased (p < 0.001) to approximately 0.25 mmol/L within one month, and the level remained almost the same thereafter. The serum phosphate level did not change without adjusting the original dose of calcium carbonate as a phosphate binder. We concluded that low Ca dialysate (1.25 mmol/L) is effective for the treatment of CAPD-related hypoparathyroidism with low bone turnover.

Aged↗