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Biomedical subjects

T Shigematsu

Publications and source records attributed to T Shigematsu.

At least 73 records · Page 4Linked to original sources
PubMed1997

[Evaluation of changes in destructive spondylarthropathy (DSA) in long-term dialysis patients].

This study was undertaken to evaluate destructive spondylarthropathy (DSA) in patients long-term dialysis. The patients were investigated by plain X-ray examinations twice with a three-year interval, and the changes in severity of the illness in 66 patients undergoing dialysis for over 5 years were defined. Group A (9 patients) consisted of patients with progression in grades during the three years, while group B (57 patients) consisted of patients without deterioration. There was no differences in the two groups in age, duration and the modality of dialysis. However, in group A, the level of plasma beta 2-microglobulin (beta 2M) was 33.5 +/- 14.6 micrograms/ml at the first observation, and 33.1 +/- 15.1 micrograms/ml at the second (NS). In group B, the level of plasma beta 2M was 45.6 +/- 8.13 micrograms/ml at the first observation, and 39.7 +/- 9.18 micrograms/ml at the second (p <0.05). No improvement in DSA was observed. The result of this study suggests that DSA will not improve once it has become overt, and the management for lowering the level of beta 2M may prevent the occurrence and progression of DSA.

Adult↗
PubMed1997

[Type III procollagen N-peptide and hyaluronate in serum and dialysate of CAPD patients].

Long-term CAPD may develop peritoneal fibrosis, which is thought to be related to permanent loss of ultrafiltration capacity and sclerosing peritonitis. In CAPD patients, we examined the serum (P-) and effluent (D-) levels of type III procollagen N-peptide (P III P) and hyaluronate (HA), which are expected to change concomitantly with a local increase in submesothelial extracellular matrix of the peritoneum. We selected 40 CAPD patients (age: 46.3 +/- 11.3 years, time on CAPD: 33.6 +/- 26.2 months), who were not suffering from chronic liver disease, any inflammatory disease, nor peritonitis during the previous month. P-P III P, P-HA, D-P III P, and D-HA were measured by PET (values after 4-hour dwelling). D/P ratios (P III P 0.330 +/- 0.137, HA 5.68 +/- 6.44) suggested that their source was from the peritoneum. Although neither P-P III P nor log P-HA value had a significant correlation with age nor time on CAPD, both had significantly positive correlations (p = 0.0009, 0.0005, respectively) with time on total dialysis (including hemodialysis). D-P III P did not have a significant correlation with age nor time on total dialysis but had a significantly positive correlation (p = 0.0098) with D/P-creatinine. Although log D-HA had significantly positive correlations with time on CAPD and time on total dialysis (p = 0.0007, 0.0051, respectively), time on CAPD was first entered (F = 16.5) and time on total dialysis was removed (F to enter: 4) by stepwise regression analysis. In conclusion, a local increase in extracellular matrix of the peritoneum in CAPD patients, indicated by increases in P III P and HA in the effluent, may be related to higher peritoneal permeability and a longer duration of PD.

Adult↗
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↗
PubMed1996

[Pediatric fiberoptic bronchoscopy via the laryngeal mask airway].

Fiberoptic bronchoscopy was performed on 11 children aged from 6 months to 3 years and weighing between 2.1 and 12.5 kg using the laryngeal mask airway (LMA). The LMA allows observation of subglottic stenosis which can not be seen under tracheal intubation. The smaller prototype of the fiberoptic bronchoscope whose diameter is 1.8mm has no provision for angulation at the tip. However, using the LMA as a guide it was easy to reach the subglottic stenosis even using this smaller bronchoscope.

Anesthesia, General↗