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Biomedical subjects

T Ito

Publications and source records attributed to T Ito.

At least 541 records · Page 30Linked to original sources
PubMed1999

Dobutamine stress echocardiography at 7.5 mg/kg/min using color tissue Doppler imaging M-mode safely predicts reversible dysfunction early after reperfusion in patients with acute myocardial infarction.

Dobutamine stress echocardiography (DSE) is widely used to predict reversible left ventricular dysfunction, but evaluation by this method is subjective. The recently developed color tissue Doppler imaging (TDI) M-mode may permit objective and quantitative assessment of changes in wall motion induced by DSE. We tested the hypothesis that this new method can detect sensitively reversible dysfunction in the post-myocardial infarction setting. DSE with color TDI M-mode and conventional DSE were performed to predict reversible dysfunction in 53 patients at a mean of 3 days after infarction using 7.5 and 10 microg/kg/min of dobutamine. Follow-up regular echocardiography (4 weeks later) was used as the reference technique to define reversible dysfunction segments. To predict reversible dysfunction segments, the standard segmental wall motion score change on conventional DSE and the ratio of the segmental wall velocity difference at rest versus stress (7.5 and 10 microg/kg/ min) on DSE with color TDI M-mode (7.5-TDI-M and 10-TDI-M, respectively) were used. With 7.5 microg/kg/min of dobutamine, the sensitivity for predicting reversible dysfunction using color TDI M-mode (7.5-TDI-M) was significantly higher than that of conventional DSE (89% vs 73%, p <0.05) whereas specificities and predictive values were almost identical. With a 10-microg/kg/min dose, color TDI-M mode (10-TDI-M) and conventional DSE were not significantly different in predicting reversible dysfunction. With use of color TDI-M mode, regional wall motion during DSE was analyzed objectively and quantitatively. Moreover, combined TDI-M and conventional data were slightly superior to either mode alone. There were no arrhythmias during 7.5 microg/kg/min of dobutamine, but 9 arrhythmias occurred during the 10-microg/kg/min dose in patients with acute myocardial infarction. In conclusion, color TDI M-mode permits objective and quantitative assessment of regional ventricular wall motion and gives additional information for detecting reversible dysfunction in DSE. Improvement of sensitivity at a lower dose of dobutamine with color TDI-M mode may increase the safety of DSE in the post-myocardial infarction setting.

Angioplasty, Balloon, Coronary↗
PubMed1999

Abnormal proliferation of CD4- CD8+ gammadelta+ T cells with chromosome 6 anomaly: role of Fas ligand expression in spontaneous regression of the cells.

We report a case of granular lymphocyte proliferative disorder accompanied with hemolytic anemia and neutropenia. Phenotypes of the cells were T cell receptor gammadelta+ CD3+ CD4- CD8+ CD16+ CD56- CD57-. Southern blot analysis of T cell receptor beta and gamma chains demonstrated rearranged bands in both. Chromosomal analysis after IL-2 stimulation showed deletion of chromosome 6. Sorted gammadelta+ T cells showed an increase in Fas ligand expression compared with the levels in sorted alphabeta+ T cells. The expression of Fas ligand on these gammadelta+ T cells increased after IL-2 stimulation. The patient's anemia improved along with a decrease in granular lymphocyte count and disappearance of the abnormal karyotype without treatment. The expression of Fas ligand may be involved in spontaneous regression of granular lymphocyte proliferation with hemolytic anemia.

Anemia, Hemolytic↗
PubMed1999

Model of mouse pancreaticoduodenal transplantation.

Our technical procedure for mouse pancreaticoduodenal transplantation is described. A number of methods were attempted. Among them, a modification of S. Lee's method was thought to be the most successful procedure, which was performed with end-to-side anastomosis of the donor portal vein to the inferior vena cava and that of the donor aortic patch to the aorta. Even with this method, however, arterial thrombosis or venous stenosis of the anastomoses was inevitable without the use of some devices as well as special skills in microsurgery.

Anastomosis, Surgical↗
PubMed1999

Significant role of intragraft lymphoid tissues in preventing insulin-dependent diabetes mellitus recurrence in whole pancreaticoduodenal transplantation.

Graft recurrence of insulin-dependent diabetes mellitus (IDDM) was examined. Islet transplantation or pancreas-alone transplantation excluding the duodenum and peripancreatic lymph nodes was compared with whole pancreaticoduodenal transplantation. A Wistar Furth (WF; RT1(u), RT6.2) to major histocompatibility complex (MHC)-compatible diabetes-prone (DP; RT1(u), RT6.1 gene carrier)-biobreeding (BB) rat transplantation model was used. Only DP recipients that had been transplanted with whole pancreaticoduodenal grafts were free from IDDM recurrence (>60 days postgrafting) when treated with anti-intercellular adhesion moluecule-1 (ICAM)-1/leukocyte function-associated antigen-1 (LFA-1) monoclonal antibodies (mAbs). In the spleen cells of the DP rats that had accepted pancreatic grafts (60 days postgrafting), flow cytometric analysis showed that NKR-P1(+)TCRalphabeta(+) (NKT) cells had proliferated markedly, with the proportion of 12.8 +/- 1.7% in the total splenic T cells, most of which (86.2%) were derived from the donor (RT6.2(+)). By enzyme-linked immunonosorbent assay (ELISA), serum interferon gamma (IFN-gamma) was not detected (<13 pg/ml) in all rats. However, interleukin-4 (IL-4) was detected as 158.8 +/- 28.0 pg/ml in the nonrecurrent DP recipients. These data suggested that to prevent IDDM recurrence in the pancreatic graft, the lymphocytes in the pancreaticoduodenal grafts are necessary. Also, the donor-derived NKT cells might have some immunoregulatory functions with a Th2 deviation.

Animals↗
PubMed1999

Photoregulation of the Formation and Dissociation of a DNA Duplex by Using the cis-trans Isomerization of Azobenzene.

The duplex-forming activity of an oligonucleotide has been photoregulated by making use of the isomerization of an azobenzene moiety in the side chain. When the azobenzene moiety is isomerized from the trans form to the cis form upon photoirradiation, the melting temperature of the duplex between the oligonucleotide and its complementary counterpart is significantly lowered, and the duplex is largely dissociated into two single-stranded oligonucleotides (shown schematically).

Journal Article↗
PubMed1999

Magnitude subtraction vs. complex subtraction in dynamic contrast-enhanced 3D-MR angiography: basic experiments and clinical evaluation.

Magnitude subtraction and complex subtraction in dynamic contrast-enhanced three-dimensional magnetic resonance (3D-MR) angiography were compared using a phantom and 23 human subjects. In phantom studies, complex subtraction showed far better performance than magnitude subtraction, especially for longer echo times, with thicker slices, and without fat suppression. With complex subtraction, non-fat-suppressed studies showed contrast-to-noise ratios comparable to those in fat-suppressed studies. In human subjects, complex subtraction was superior to magnitude subtraction in 9 subjects, but comparable to magnitude subtraction in 14 subjects. There were no cases in which magnitude subtraction was superior to complex subtraction. Although the differences observed in human studies when complex subtraction was applied with thinner slices, shorter echo times, and the fat-suppression technique were not as pronounced as those seen in phantom studies, complex subtraction should be performed in dynamic contrast-enhanced 3D-MR angiography because there are no drawbacks in complex subtraction. Further research is necessary to assess the feasibility of dynamic contrast-enhanced 3D-MR angiography without fat suppression in human subjects using complex subtraction, as suggested by the results of phantom studies. If it is found to be feasible, dynamic contrast-enhanced 3D-MR angiography without fat suppression using complex subtraction may prove to be a robust technique that eliminates the need for shimming and can reduce the acquisition time. J. Magn. Reson. Imaging 1999;10:813-820.

Adult↗
PubMed1999

Evaluation of contrast agents for delineation of vessel wall boundary by intracoronary ultrasound after coronary angioplasty in human.

We evaluated the potential for improving visualization at intervention sites using contrast-enhanced intracoronary ultrasound (ICUS) and the suitable contrast agents for this procedure in humans. In 37 patients, ICUS (30 MHz) was performed with intracoronary bolus injection (3 mL) of seven different contrast preparations and without the contrast agents (control) after coronary intervention. The contrast agents used were as follows: saline solution, standard iomeprol, standard ioxaglate, sonicated iomeprol, sonicated ioxaglate, 50% Albunex, and 100% Albunex. Homogeneous and complete opacification of the vessel lumen and false lumen was observed with sonicated ioxaglate, 50% and 100% Albunex. Shadowing was not observed at all with sonicated ioxaglate and was uncommon with 50% Albunex, whereas 100% Albunex caused shadowing in all cases. The coronary delineation rate with the other contrast agents was only 60%-70%, and the homogeneity and peak intensity were relatively low. Thus, sonicated ioxaglate and 50% Albunex both achieved good visualization, but the latter is more expensive, more difficult to handle, and takes longer to prepare. Of the agents we studied, sonicated ioxaglate appears to be best suited for contrast-enhanced ICUS. ICUS using suitable contrast agents could only visualize the large dissections and the strategy was changed according to the contrast-enhanced ICUS results in five cases. Thus, suitable contrast agents, e.g., sonicated ioxaglate, should be used during ICUS after intracoronary intervention.

Aged↗
PubMed1999

Relationship of matrix metalloproteinases and their inhibitors to cartilage proteoglycan and collagen turnover: analyses of synovial fluid from patients with osteoarthritis.

OBJECTIVE: To determine the relationship between matrix metalloproteinases (MMPs), their inhibitors, and the turnover of matrix molecules in articular cartilage from patients with osteoarthritis (OA). METHODS: Synovial fluid samples were collected from the knees of 54 patients with OA. Radiographic evaluations and magnetic resonance imaging were performed on the knees of 34 OA patients to classify the stage of the disease. Biochemical analyses and immunoassays were used to measure the concentrations of MMP-1, MMP-3, tissue inhibitor of metalloproteinases 1 (TIMP-1), TIMP-2, the disaccharide of hyaluronic acid, the proteoglycan glycosaminoglycan disaccharides of chondroitin 4-sulfate (delta di-CS4) and chondroitin 6-sulfate (delta di-CS6), the 846 epitope on chondroitin sulfate of cartilage proteoglycan aggrecan (putative biosynthetic marker), the keratan sulfate (KS) epitope of aggrecan (putative degradation marker), and the C-propeptide of cartilage type II procollagen (CPII) (biosynthetic marker). RESULTS: The concentration of TIMP-1 was directly correlated with the levels of MMP-1 and MMP-3 (both were also correlated with each other), confirming earlier results. There was an inverse correlation between the delta di-CS6:delta di-CS4 ratio and the concentration of MMP-3. The level of delta di-CS6 was correlated with that of the KS epitope, and to a lesser degree, with that of the 846 epitope (the latter was also correlated with the level of delta di-CS4). The concentration of TIMP-1 correlated with that of the 846 epitope, whereas TIMP-2 levels correlated with those of CPII. There were significantly lower concentrations of delta di-CS6, delta di-CS4, the 846 epitope, and CPII in synovial fluid from patients with late-stage OA. CONCLUSION: These observations suggest a link between proteolysis and inhibitor concentrations in OA cartilage. Production of TIMPs appears to be individually linked to the synthesis of specific cartilage molecules. The reduction in the amount of cartilage-matrix structural components suggests that there is a measurable loss of cartilage in the late stages of the disease, as suggested previously. The resultant composition of the cartilage suggests that the loss may primarily involve "resident" molecules originally present in healthy cartilage.

Aged↗
PubMed1999

Expression of functional CD40 in human hepatocellular carcinoma.

CD40, a member of the tumor necrosis factor receptor (TNFR) family, plays a crucial role in the survival, proliferation, and differentiation in B cells. However, the expression of CD40 other than in B cells has not been well studied. Therefore, we investigated the expression and function of CD40 in hepatocellular carcinomas (HCCs). Expression of CD40 mRNA in 6 established HCC cell lines was analyzed by reverse-transcription polymerase chain reaction (RT-PCR) and CD40 expression on cell surface was examined by flow cytometrical analysis. We also examined the expression of CD40 in human HCC tissues (45 cases) and nontumor liver tissues (30 cases) by immunohistochemistry. To examine the function of CD40 in HCC cells, we investigated the effect of CD40 signaling on anti-Fas antibody and TNF-alpha-induced apoptosis in HepG2 cells. In addition, intracellular levels of cysteine protease P32 (CPP32) protein in HepG2 cells were also determined by Western blotting. We have shown that 6 HCC cell lines constitutively expressed CD40 mRNA and membrane-bound CD40 antigen, which was slightly up-regulated by interferon gamma (IFN-gamma). In addition, 60% of human HCC tissues demonstrated positive staining for CD40, whereas nontumor tissues showed little detectable staining. In HepG2 cells, CD40 stimulation does not affect cell viability, but significantly inhibited Fas and TNFR-mediated apoptosis in a dose-dependent manner by blocking the activation of CPP32. From these results, we conclude that CD40 expression in HCCs plays an important role in tumor biology, especially the resistance against Fas and TNFR-mediated apoptosis.

Apoptosis↗
PubMed1999

The importance of total parenteral nutrition-associated tissue zinc distribution in wound healing.

It is well known that zinc (Zn), an essential trace element, plays a role in wound healing. Although the importance of Zn supplementation in total parenteral nutrition (TPN) has been recognized, the difference in tissue Zn distribution induced by TPN and whether this difference influences local wound healing remains uncertain. Thus, we conducted a study using 30 Sprague-Dawley rats to investigate the influence of TPN-induced changes in tissue Zn distribution on wound healing at sites of intestinal anastomosis, muscle, and skin sutures. In the ordinary diet group, no significant differences were observed between subgroups with and without supplemental Zn in tissue Zn distribution or in the healing of intestinal, muscular, and cutaneous wounds. In the subgroup given a low-protein diet without supplemental Zn, a gross change in tissue Zn distribution was noted to occur with a concomitant marked decrease in Zn concentration and the tensile strength of wounded skin. These results indicate an association between wound healing and Zn concentration in the respective tissues in TPN-induced Zn deficiency with alternations in tissue Zn distribution. They also provide evidence of the local action of Zn in wound healing.

Analysis of Variance↗
PubMed1999

The surgical treatment of fixed subaortic stenosis: a clinical experience in Japan.

We report herein the results of a retrospective study conducted on ten consecutive Japanese patients who underwent successful surgical relief of fixed subaortic stenosis between 1972 and 1994 at ages ranging from 8 months to 21 years, and followed for 3.6 years and 26 years. Associated cardiovascular defects were present in six patients, two had a history of infective endocarditis, a discrete fibrous ring was found in nine patients, and a redundant abnormal sheet was found in one. A stenotic structure was removed in nine patients and incised in one, while myotomy was additionally performed in one. There were no early complications or deaths. Cardiac catheterization revealed a significant decrease in the peak systolic pressure gradient from 84+/-22 mm Hg preoperatively to 32+/-22 mm Hg postoperatively (P = 0.0017). Reoperation of an aortic valve replacement with or without valvular annulus enlargement was required in four patients because of a small annulus with aortic insufficiency or infective endocarditis. Infective endocarditis was a major cause of late mortality (n = 1) and morbidity (n = 1), but the remaining eight patients have been asymptomatic. Thus, although this lesion is relatively rare in Japan, the typical discrete type may be more common than previously believed. While a relief operation is associated with low early mortality, the palliative aspect regarding pathology of the aortic valve should not be underestimated, including poor growth of the valve annulus, deterioration of aortic insufficiency, and infective endocarditis. The most appropriate operative procedure for reoperation remains to be evolved.

Adolescent↗
PubMed1999

Effects of arteriovenous shunt on ventricular function in dog.

BACKGROUND: The bidirectional cavopulmonary shunt has been increasingly accepted as an interim step to the Fontan operation. However, the effect(s) of chronic volume overload on ventricular function are not yet well understood. METHODS: Twelve mongrel dogs, with (chronic volume overload group), or without (control group) a femoral arteriovenous shunt created 8 weeks before the assessment, were subjected to a right heart bypass from the right atrium to the proximal pulmonary trunk. Nonpulsatile perfusion via the bypass was achieved using a centrifugal pump and cross-clamping of the pulmonary trunk. Left ventricular function was evaluated using the end-systolic elastance and the Doppler flow pattern on echocardiograms (epicardiac and transesophageal, simultaneously) during acute volume loading. RESULTS: The left ventricular weight and the left ventricular weight/end-diastolic volume ratio showed no change from control values. The sum of the isovolumetric contraction time and the isovolumetric relaxation time divided by the ejection time remained constant during acute volume loading in the chronic volume overload group, while an increase was demonstrated in the control group. The chronic volume overload group showed a lower Ees (30.8 +/- 16.4 mmHg/cm2 vs. 107.6 +/- 70.3 mmHg/cm2, p = 0.03) than the control group. CONCLUSIONS: The global ventricular performance changed with chronic adaptation to the arteriovenous shunt, and became resistant to acute volume loading. Left ventricular contractility under nonpulsatile pulmonary perfusion was impaired by chronic volume overload, which is deleterious to the Fontan operation.

Animals↗
PubMed1999

Sporadic amyotrophic lateral sclerosis with multiple system degeneration: a report of an autopsy case without respirator administration.

This report concerns an autopsy case of amyotrophic lateral sclerosis (ALS) with unusual clinical and neuropathological findings. The patient was a Japanese man without hereditary burden who was 49 years old at the time of death. His clinical manifestation included dysarthria at age 48, followed by dysphagia, atrophy and fasciculation of the tongue, muscle weakness in the four extremities, tremor, rigidity, increased deep tendon reflexes in the upper and lower extremities, and incoordination of the four extremities. He died of respiratory failure 12 months after the disease onset. No respirator administration was performed throughout the clinical course. The neuropathological examination revealed not only degeneration of upper and lower motor neuron systems, including the presence of Bunina bodies and ubiquitin-immunoreactive neuronal inclusions in the lower motor neurons, but also prominent degeneration of the substantia nigra and dentate nucleus with slight neuronal loss in the locus ceruleus and pontine nucleus. To our knowledge, this is the first reported case of sporadic ALS without dementia and respirator support, showing degeneration of the substantia nigra and dentate nucleus. This report may contribute to the resolution of the question concerning the neuropathological heterogeneity of sporadic ALS with respiratory support.

Amyotrophic Lateral Sclerosis↗
PubMed1999

Ontogeny of pulmonary neuroendocrine cells which express the alpha-subunit of guanine nucleotide-binding protein Go.

In order to ascertain that alpha-subunit of guanine nucleotide-binding protein Go (Go alpha)-positive cells in the lung epithelia are pulmonary neuroendocrine cells (PNECs), we carried out an immunohistochemical study in young adult and fetal lungs of rodents and in cultured fetal lung explants. Serial sections showed that Go alpha-positive cells were immunostained for calcitonin gene-related peptide and serotonin in young adult mouse, rat, and hamster lungs and that these cells are, therefore, PNECs. In the fetal lungs of hamster and mouse, Go alpha-positive PNECs appeared in the epithelium of the lobar bronchus by gestational day 13 in hamster and by day 15.5 in mouse, and they increased with a proximal-to-distal wave during the late fetal period. Explants of immature lung from the fetal hamster on gestational day 11 were cultured. After 2 days of culture, Go alpha-positive PNEC clusters appeared in the main and lobar bronchi and many PNEC clusters were seen after 4 days of culture. To determine the functional significance of Go in the development of the fetal lung, pertussis toxin, a Go inhibitor, was added to the medium, and changes in branching morphogenesis and PNEC development were studied. Although branching morphogenesis was not disturbed by pertussis toxin, the toxin treatment induced large PNEC clusters in the cultured lung explant. In summary, we showed that Go alpha is a neuroendocrine marker for PNECs and that Go alpha-positive cells appear along with development of PNECs in fetal hamster lung in vivo and in vitro. The functional significance of Go in the development of fetal lung is obscure, but signals mediated through this GTP-binding protein could be related to some functions of PNECs.

Animals↗
PubMed1999

Cellular localization and distribution of glucocorticoid receptor immunoreactivity and the expression of glucocorticoid receptor messenger RNA in rat pituitary gland. A combined double immunohistochemistry study and in situ hybridization histochemical analysis.

By means of double immunohistochemical techniques and a nonradioisotopic in situ hybridization method, we determined the colocalization pattern of glucocorticoid receptor (GR) and pituitary hormones and the GR messenger RNA (mRNA) expression in the pituitaries of Wistar adult male rats. Immunoreactivity for GR was detected in the nuclei of cells in the anterior and posterior pituitary. Double immunohistochemistry revealed that the colocalization of GR and anterior pituitary hormones occurred in almost 99% of the growth hormone (GH)-producing cells and adrenocorticotropic hormone (ACTH)-producing cells, and in 67% of the thyroid stimulating hormone (TSH)-producing cells. Almost all of the folliculostellate cells (93%), marginal layer cells (94%) in the anterior pituitary, and pituicytes (96%) in the posterior pituitary immunostained for S100 protein antibody were also immunostained with GR. GR mRNA was abundant in the cytoplasm of anterior and intermediate pituitary cells but scattered sparsely in that of the posterior pituitary. These results suggest that glucocorticoids directly influence certain pituitary cells in order to regulate cell function, including the synthesis and/or secretion of hormones.

Animals↗
PubMed1999

Identification of connexins in human oral mucosa and therapeutic effect of irsogladine maleate on aphthous stomatitis.

We identified connexins 26 and 32 in human oral mucosa. The presence of the connexins indicates the presence of gap junctions in this tissue. However, immunofluorescence study found no significant differences in the expression of the connexins between patients with aphthons stomatitis and controls. Irsogladine maleate, which reinforces gap junctional intercellular communication in vitro, was effective for the treatment of transient and relapsing aphthous stomatitis, as well as symptomatic and drug-induced aphthous stomatitis. It was also useful for prevention of episodes of relapsing aphthous stomatitis, with daily administration preverting recurrence of stomatitis for more than 4 years one patient. These findings suggest that irsogladine maleate accelerates the wound healing process in oral mucosa by reinforcing gap junctional intercellular communication among oral mucosal cells; and that it is useful for the treatment and prevention of aphthous stomatitis.

Adult↗
PubMed1999

Screening for gastroenterological malignancies in new and maintenance dialysis patients.

To screen for gastroenterological malignancies in dialysis patients, we used the fecal occult blood test, examined the upper and lower gastrointestinal tract, and used abdominal ultrasonography in 178 patients starting dialysis (171 on hemodialysis and 7 on continuous ambulatory peritoneal dialysis (CAPD)) and 34 patients on maintenance dialysis (27 on hemodialysis and 7 on CAPD). Screening disclosed ten cancers (one esophageal cancer, three gastric cancers, four colorectal cancers, and two hepatocellular carcinomas) in 9 of the patients starting dialysis. Six cancers (one esophageal, three gastric, one colorectal, and one renal) were detected in 5 of the patients on maintenance dialysis. Since an increased incidence of malignancy has been reported in dialysis patients, gastroenterological screening appears to be worthwhile.

Abdomen↗