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Biomedical subjects

Y Imai

Publications and source records attributed to Y Imai.

At least 523 records · Page 29Linked to original sources
PubMed1995

Attachment and growth of cultured fibroblast cells on silk protein matrices.

The attachment and growth of L-929 cells on films made of Bombyx mori silk proteins--fibroin and sericin and their mixtures--was studied by a cell culture method. Both cell attachment and growth were dependent on a minimum of around 90% sericin in the mixture. The results from electron micrography as well as from the DSC measurements supported the notion that the mixture of the two proteins fibroin and sericin has a phase-separated structure in the solid state. The observed minimum of sericin in the cell attachment and growth is thought to be a result of this phase-separated structure. Films of pure component proteins (i.e., 100% fibroin or sericin) exhibited as high a cell attachment and growth as collagen, a widely used mammalian cell culture substrate. However, a morphological study of the attached cells revealed that the cells attached to silk fibroin were extended and had a spindle shape, just like the cells attached to collagen, while the cells attached to the silk sericin had a different shape. It is concluded, therefore, that the attachment condition on silk fibroin is ideal for the viability, growth and function of the cells.

Amino Acids↗
PubMed1995

Enhancement in accessibility to macrophages by modification of mucin-type carbohydrate chains on a tumor cell line: role of a C-type lectin of macrophages.

We investigated the role of mucin-type (O-linked) carbohydrate chains of tumor target cells in the recognition by macrophages through a Gal/GalNAc-specific calcium-dependent lectin. Binding of a soluble form of this lectin to P815 mastocytoma cells was increased by treatment with benzyl-GalNAc, which presumably inhibited the extension of mucin-type carbohydrate chains. The levels of cell surface expression of GalNAc residues were elevated after benzyl-GalNAc treatment, as revealed by the binding of Vicia villosa agglutinin B4 and Dolichos biflorus agglutinin. Adhesion of treated P815 cells to this lectin immobilized on plastic surfaces also increased. Furthermore, the binding of P815 cells to macrophage-like RAW 264.7 cells and to peritoneal macrophages also increased after the same treatment. We concluded that elevated levels of cell surface terminal GalNAc in mucin-type carbohydrate chains increased accessibility of P815 cells to macrophages through Gal/GalNAc-specific calcium-dependent lectins.

Acetylgalactosamine↗
PubMed1995

Immunohistochemically defined lymphocyte function-associated antigen 1 (LFA-1) on an adenocarcinoma cell line is a distinct molecule from LFA-1 on leukocytes.

We previously reported that the immunohistochemically defined LFA-1 antigen (LFA-1-like antigen) was expressed on various exocrine tissues uninvolved with tumors in patients with malignant diseases using LFA-1 alpha-specific monoclonal antibodies (mAb) 2F12 and HVS6B6. In this study we investigated differences at the molecular level between LFA-1 on leukocytes and LFA-1-like antigen on MKN45.16, a subline derived from an adenocarcinoma line MKN45 that expresses a high amount of LFA-1-like antigen. LFA-1-like antigen was reactive to mAb 2F12 or HVS6B6, but not to any of the other five different LFA-1 alpha (CD11a)-specific or four LFA-1 beta (CD18)-specific mAb. mAb 2F12 immunoprecipitated a 200-kDa membrane protein (LFA-1-like antigen) from MKN45.16 cells, whereas it precipitated 180-kDa (LFA-1 alpha) and 95-kDa (LFA-1 beta) proteins from a monocytic cell line (THP-1) under both nonreducing and reducing conditions. The molecular difference was confirmed further by N-glycanase treatment of the immunoprecipitates. The isoelectric point of LFA-1-like antigen was 6.0, whereas those of LFA-1 alpha and LFA-1 beta were 6.0 and 4.7, respectively, by two-dimensional gel electrophoresis. Expression of LFA-1 alpha gene on MKN45.16 cells was not detected at the mRNA level by six different sets of LFA-1 alpha-specific oligonucleotides and reverse transcription-polymerase chain reaction. These results indicated that LFA-1-like antigen on an adenocarcinoma cell line was a distinct molecule from LFA-1 on leukocytes.

Adenocarcinoma↗
PubMed1995

Urinary alpha1-microglobulin, beta2-microglobulin, and retinol-binding protein levels in general populations in Japan with references to cadmium in urine, blood, and 24-hour food duplicates.

Possible cadmium (Cd) exposure-associated changes in urinary levels of low-molecular-weight proteins were studied in nonsmoking and non-drinking female members of the general Japanese population (378 subjects with no known occupational heavy metal exposure) who lived at 19 study sites (all without any known environmental heavy metal pollution) in 13 prefectures throughout Japan. The external Cd dose was evaluated in terms of daily Cd intake via food (Cd-F), whereas Cd levels in blood (Cd-B) and urine (Cd-U) were taken as internal dose indicators. When the subjects were classified according to Cd-F into three groups with "low" (20.4 micrograms/day as a geometric mean of 97 women), "middle" (35.0 micrograms/day, 120 women) and "high" (67.0 micrograms/day, 66 women) exposure, both Cd-B and Cd-U increased in parallel with the changes in Cd-F. However, there were no dose-dependent changes in beta2-microglobulin or retinol-binding protein levels in urine, alpha1-microglobulin levels appeared to increase, but the distribution of the cases above the two cutoff levels of 9.6 and 15.8 micrograms/mg creatinine among the three Cd-F groups did not show any bias. Overall, it was concluded that there was no apparent Cd exposure-associated elevation in urinary low-molecular-weight protein levels in the study population.

Alpha-Globulins↗
PubMed1995

Thymoma: tumour type related to expression of epidermal growth factor (EGF), EGF-receptor, p53, v-erb B and ras p21.

As clinicopathological features may not be sufficient to predict the progression of thymoma, we have carried out what we believe to be the first immunohistochemical study describing the relationship between the different types of thymoma and the tumour stage, on the one hand, and the expression of epidermal growth factor (EGF), EGF-receptor (EGFR), p53, v-erb B and ras p21, on the other. The positive rates versus histological types and Masaoka's clinical stages in the 47 cases were as follows: p53 (non-invasive thymoma: 41.7%; malignant thymoma category I: 82.4%; malignant thymoma category II: 83.3%), EGF (non-invasive thymoma: 4.2%; malignant thymoma category I: 11.8%; malignant thymoma category II: 33.3%) and EGFR (non-invasive thymoma: 8.3%; malignant thymoma category I: 35.3%; malignant thymoma category II: 66.7%); p53 (stages I and II: 51.7%; stages III and IV: 77.8%), EGF (stages I and II: 3.4%; stages III and IV: 22.2%) and EGFR (stages I and II: 13.8%; stages III and IV: 44.4%). These data suggest that p53 may be implicated in the initial stages of tumorigenesis and that increased expression of EGF and EGFR may play a role in thymoma progression.

Adult↗
PubMed1995

Muscle cramps and elevated serum creatine phosphokinase levels induced by beta-adrenoceptor blockers.

We have assessed the propensity of beta-adrenoceptor blockers to cause muscle cramps and to raise the serum creatine phosphokinase (CPK) level in 78 patients with essential hypertension. After a control period, a beta-adrenoceptor blocker without intrinsic sympathomimetic activity (ISA; propranolol, metoprolol or arotinolol) was administered for three months. Thereafter, the patients were randomised to receive a beta-adrenoceptor blocker with ISA (pindolol or carteolol) for three months or a beta-adrenoceptor blocker without ISA for a further three months. This pattern was continued until all beta-adrenoceptor blockers had been given. At the end of each period, CPK and CPK-MB levels were measured. Of the 78 subjects, muscle cramps occurred in 27 during treatment with pindolol and 32 during treatment with carteolol. No complaints were made by subjects treated with propranolol and arotinolol, but muscle cramps were reported in 2 treated with metoprolol. While muscle cramps were caused both by pindolol and carteolol in 16 subjects, they were caused by either of these drugs in the remainder of the subjects. Muscle cramp occurred mainly in the calves when the patients were in bed at night. Serum CPK and CPK-MB levels increased significantly during treatment with pindolol (control period vs pindolol, CPK = 96 vs 133 IU.ml-1, CPK-MB = 14 vs 18 IU.ml-1) or carteolol (CPK = 117 IU.ml-1, CPK-MB = 18 IU.ml-1) while the levels during treatment with propranolol, arotinolol and metoprolol did not change from those in the control period.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Antagonists↗
PubMed1995

Changes in the mononuclear cell subpopulations of rat cardiac transplant recipients administered FK506 for the treatment of ongoing rejection.

The inhibitory effect of ongoing rejection and the changes that occurred in mononuclear cell subpopulations were compared between four groups of rats treated with FK506 or steroids. Group 1 was given no immunosuppressive drugs, group 2 was given FK506 from the day of grafting, group 3 was commenced on FK506 on the 4th day after grafting, and group 4 was commenced on methylprednisolone (MP) on the 4th day after grafting. The graft survival times in groups 2 and 3 were significantly longer than those in groups 1 and 4, and there were fewer CD3+ and CD4+ T lymphocytes in the peripheral blood in the groups treated with immunosuppressive drugs than in group 1. In group 4, the levels in both the peripheral blood and thymus were significantly lower than those in the groups treated with FK506 despite the fact that graft rejection occurred soon after the discontinuation of steroid administration. Moreover, the levels of interleukin-2 receptors and macrophages in groups 2, 3, and 4 were significantly lower than that in group 1 postoperatively; however, the number of macrophages in groups 2 and 3 was significantly lower than that in group 4 on the 10th day after transplantation. The findings of this study demonstrated that FK506, even if administered after rejection has begun, might inhibit the subsequent extensive allograft rejection more specifically and effectively than steroids, and that the measurement of a marker for macrophages in the peripheral blood could be useful for the detection of rejection following allograft transplantation in rats.

Animals↗
PubMed1995

Coronary artery-pulmonary artery fistula in pulmonary atresia with ventricular septal defect.

This paper reports two patients presenting a combination of coronary artery-pulmonary artery fistula and pulmonary atresia with ventricular septal defect. A confluent central pulmonary artery arose from the proximal portion of the left coronary artery in both patients. The fistulous segment between the coronary artery and the central pulmonary artery was large, and no coronary arterial stenosis was found in either patient. Besides this fistulous origin of the pulmonary blood supply, large collateral vessels originated from the descending aorta in both patients. Neither patient has shown findings of myocardial ischemia, at least in consecutive rest and exercise electrocardiograms. Both patients were successfully operated, at the ages of 3 and 8 years, respectively. The clinical and embryological implications of this rare malformation are briefly reviewed.

Arteriovenous Fistula↗
PubMed1995

The effect of graded calcium infusions on rhythmic blood pressure oscillations in normal man.

This study was designed to determine whether calcium contributes to the regulation of rhythmic oscillations in blood pressure. Six normal subjects received sequential 1-h infusions of calcium gluconate (1.5, 3.0 and 4.5 mg calcium/kg/h) during continuous blood pressure (Finapres) monitoring. The plasma ionized calcium ([Ca2+]) concentration increased from 4.6 +/- 0.07 mg/dl to 5.97 +/- 0.20 mg/dl (p < 0.01) with infusion. The mid-frequency (0.07-0.14 Hz, Mayer wave) power spectrum of diastolic blood pressure was depressed slightly following the first dose but increased significantly following the final dose (p < 0.05). The high-frequency (0.15-0.40 Hz) power spectrum of systolic blood pressure decreased following the first dose (p < 0.05) and subsequently remained low. The low-frequency (0.02-0.6 Hz) power spectrum was not affected. These results demonstrate that graded hypercalcaemia affects blood pressure oscillations in man. Our data suggest that the amplitude of the Mayer wave, a clinical marker of sympathetic vascular tone, is modulated in part by calcium.

Adult↗
PubMed1995

Clinical usefulness of digital radiography in the gastrointestinal tract: efficacy of magnification method.

We assessed the performance capabilities of image intensifier digital radiography (II DR) in the detection of minute lesions in patients with early stomach cancer. The DR system was a prototype II DR system developed by Toshiba Corp (Tokyo, Japan). This system was able to acquire images with a 1,024- x 1,024-pixel matrix and 12 bits. Radiography was performed using a 0.3-mm tube focus. For the detectability of early stomach cancer, DR was judged to be superior to conventional screen-film system (CFSS) (DR superior, 55.7%; CFSS superior, 22.6%). In depicting the characteristics of the surface of the lesion, DR was also judged to be superior to CFSS (DR superior, 56.6%; CFSS superior, 17.0%). The II DR system used in this study was able to achieve almost the same spatial resolution as conventional radiography using the magnification method. It was also able to visualize subtle findings of early gastric cancer more clearly by the use of postprocessing. In addition, II DR has the advantages of reducing the patient exposure dose and permitting the acquisition of real-time images.

Data Display↗
PubMed1995

Modulation of noradrenaline release through presynaptic alpha 2-adrenoceptors in congestive heart failure.

Stimulation of presynaptic alpha 2-adrenoceptors inhibits the release of noradrenaline from sympathetic nerve endings; however, the extent to which it operates in patients with congestive heart failure is still unknown. To investigate the degree of negative feedback to the release of noradrenaline via presynaptic alpha 2-adrenoceptors at sympathetic nerve endings, we measured plasma noradrenaline levels before and after the injection of phentolamine (i.e., plasma noradrenaline concentration at rest, plasma noradrenaline concentration after phentolamine injection [NAph], and the phentolamine-induced increase in plasma noradrenaline [delta NAph]). Plasma noradrenaline concentration at rest, NAph, and delta NAph increased in a stepwise manner from New York Heart Association class I to class III. A positive correlation was found between the plasma noradrenaline at rest and delta Naph (n = 123, r = 0.697, p < 0.001). These results suggest that the enhanced release of plasma noradrenaline is substantially buffered by the mechanism of noradrenaline release-inhibitory presynaptic alpha 2-adrenoceptors in patients with congestive heart failure, and this buffer serves to protect organs such as the heart from excess sympathetic stimulation.

Aged↗
PubMed1995

Autologous reconstruction of pulmonary trunk at reoperation after extracardiac conduit repair.

Between 1991 and 1993, 5 patients underwent reoperation for critical stenosis of extracardiac conduit. Indication for extracardiac conduit repair was pulmonary truncal atresia in 3 patients and coronary anomaly including single left coronary artery and left anterior descending artery from right coronary artery in 2 patients. Age at reoperation ranged from 8 to 23 years (mean, 16.2 years). Preoperative systolic pressure ratio of right to left ventricles ranged from 0.83 to 1.05 (mean, 0.93), with the pressure gradient across the conduit ranging from 52 to 100 mm Hg (mean, 74.4 mm Hg). At reoperation, stenotic conduit was completely removed and central pulmonary artery was extensively mobilized. In 4 patients who had a relatively short distance (15 to 25 mm) between the pulmonary arterial stump and the right ventriculotomy incision, the distal pulmonary arterial stump was anastomosed directly to the cranial margin of the right ventriculotomy incision to serve as a floor mode of autologous tissue. In 1 patient with a long distance (40 mm), right ventricular-pulmonary arterial continuity was restored with a tailored autologous pericardial tube. There were no early or late deaths. Postoperative catheterization study revealed a satisfactory reduction of right ventricular pressure with the systolic pressure ratio ranging from 0.42 to 0.51 (mean, 0.47) and the pressure gradient across the right ventricular outflow tract ranged within 13 mm Hg (mean, 5 mm Hg). Restoration of right ventricular-pulmonary arterial continuity was successfully achieved by introducing the concept of autologous tissue repair even at reoperation instead of the insertion of new extracardiac conduit in patients with tetralogy of Fallot after extracardiac conduit repair.

Adolescent↗