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Biomedical subjects

T Miyazaki

Publications and source records attributed to T Miyazaki.

At least 91 records · Page 5Linked to original sources
PubMed2001

Role of leukocytes in uterine hypoperfusion and fetal growth retardation induced by ischemia-reperfusion.

We investigated leukocyte involvement in uterine hypoperfusion and intrauterine fetal growth retardation (IUGR) induced by ischemia-reperfusion (I/R) in Sprague-Dawley rats. On day 17 of gestation, leukocyte accumulation in the uterus and placenta subjected to 30 min of ischemia, followed by reperfusion, was assessed by measuring myeloperoxidase (MPO) activity. Uterine MPO activity was significantly higher after 1 h of reperfusion than it was before ischemia (P < 0.05), without any increase in placental MPO activity. Immunohistochemical staining showed leukocyte accumulation in the uterus subjected to I/R. The effects of treatment with monoclonal antibodies against CD11a (WT1) and CD18 (WT3) at a dose of 0.8 mg/kg on uterine blood flow and IUGR were investigated. Laser-Doppler flowmetry demonstrated that uterine hypoperfusion at 2 h after ischemia (blood flow, -51.7 +/- 1.2%; P < 0.01) was inhibited by WT1 and WT3 treatment. I/R-induced IUGR at full term (P < 0.05 vs. nonischemic horn) was prevented by WT1 and WT3 treatment on day 17. These results indicate that leukocyte accumulation may play an important role in the pathogenesis of uterine hypoperfusion and IUGR induced by I/R in pregnant rats.

Animals↗
PubMed2001

Phase-advance shifts of human circadian pacemaker are accelerated by daytime physical exercise.

Effects of forced sleep-wake schedules with and without physical exercise were examined on the human circadian pacemaker under dim light conditions. Subjects spent 15 days in an isolation facility separately without knowing the time of day and followed a forced sleep-wake schedule of a 23 h 40-min period for 12 cycles, and physical exercise was imposed twice per waking period for 2 h each with bicycle- or rowing-type ergometers. As a result, plasma melatonin rhythm was significantly phase advanced with physical exercise, whereas it was not changed without exercise. The difference in phase was already significant 6 days after the start of exercise. The amplitude of melatonin rhythm was not affected. A single pulse of physical exercise in the afternoon or at midnight significantly phase delayed the melatonin rhythms when compared with the prepulse phase, but the amount of phase shift was not different from that observed in the sedentary controls. These findings indicate that physical exercise accelerates phase-advance shifts of the human circadian pacemaker associated with the forced sleep-wake schedule.

Adult↗
PubMed2001

Expression of ZAKI-4 messenger ribonucleic acid in the brain during rat development and the effect of hypothyroidism.

We identified ZAKI-4 (also designated as DSCR1L1) as a thyroid hormone responsive gene in cultured human skin fibroblasts. Recently it has been reported that ZAKI-4 belongs to an evolutionary conserved family of proteins that function as calcineurin inhibitor. In human, ZAKI-4 and calcineurin are highly expressed in brain, where thyroid hormones play essential roles in the development during fetal and neonatal periods. In the present study, we examined the temporal and spatial expression patterns of ZAKI-4 messenger RNA (mRNA) in control and hypothyroid rat brains. Northern blot analysis revealed that ZAKI-4 mRNA was detected in both cerebral cortex and cerebellum as early as embryonic day (E)18. In the cerebral cortex, the expression level gradually increased with age, reaching a plateau at postnatal day (P)7 and remained constant thereafter until P30. A similar pattern of increase with age was also observed in hypothyroid rats; however, the magnitude of the increase was significantly reduced. In control rats, the fold increase in ZAKI-4 mRNA level from E18 to P17 was 10.8; whereas in hypothyroid rats, it was 7.4. In cerebellum the expression level did not change with age or by thyroid status. In situ hybridization revealed that ZAKI-4 mRNA is widely expressed in neurons throughout the brain. It is noteworthy that the expression in the neurons of layer VI of the cerebral cortex was more evident in control rats than that in hypothyroid rats from P17 to P30. Though not influenced by hypothyroidism, there were several regions of the brain in which ZAKI-4 mRNA was strongly expressed. These regions were the mitral cell layer of the olfactory bulb, the substantia nigra, and the hippocampus, where calcineurin is also abundantly expressed. Therefore, it may be hypothesized that ZAKI-4 plays an important role in the development and function of the brain by modulating calcineurin function; and decrease in ZAKI-4 mRNA expression in the specific brain areas may explain, in some parts, the mechanism of abnormal brain development by hypothyroidism.

Animals↗
PubMed2001

Hyaluronate depolymerization following thermal decomposition of oxytetracycline.

Depolymerization of sodium hyaluronate (HA) by tetracyclines was investigated. Reduction in HA molecular weight was followed by size exclusion chromatography with a low angle laser light scattering detector. On mixing with oxytetracycline hydrochloride (OTC) solution and incubating at 37 degrees C, HA was gradually depolymerized. OTC, a representative antibiotic, is known as a photosensitizer, and phototoxic side effects relevant to radicals have been reported. However, HA depolymerization required no irradiation. As time passed, OTC solution incubated at 37 degrees C got colored reddish brown, even in the dark. With reversed-phase HPLC separation, several peaks derived from decomposed OTC appeared. One of the peaks had an absorbance in the visible range. A quantitative correlation between the discoloration and the HA depolymerization rate was obtained. On the other hand, when samples were incubated below 25 degrees C, change of color was slight, and practically no HA depolymerization was observed after up to 4 h. Oxygen depletion by nitrogen saturation or addition of mannitol also prevented the depolymerization. Under anaerobic conditions, the color of the solution did not change, whereas it turned red under aerobic conditions in the presence of mannitol. The mannitol did not inhibit the OTC decomposition, but it preserved HA from damage. On the basis of the known decomposition of OTC and the results of HPLC separation, anhydrooxytetracycline can be proposed as the derivative causing HA depolymerization.

Hot Temperature↗
PubMed2001

Stress-induced ST-segment elevation following myocardial infarction and its role in wall motion abnormality, myocardial ischemia and viability: comparison of response to exercise, dobutamine and dipyridamole.

Stress-induced ST-segment elevation following myocardial infarction (MI) has been correlated with myocardial ischemia, viability and wall motion abnormality, but its mechanism is still unclear, so the present study compared ST-segment elevation and wall motion response during exercise, dobutamine and dipyridamole stresses. Twenty-five patients with their first anterior MI underwent exercise, dobutamine and dipyridamole echocardiography on different days 4-6 weeks after MI. Left ventricular wall motion was analyzed using 5-grade/16-segment model and myocardial ischemia was considered as a worsening of the wall motion score index (WMSI) during the stress test; myocardial viability was defined as a reduction of WMSI during low dose dobutamine. Dyskinesis formation was defined by visual analysis as akinesis that became dyskinetic or if the dyskinesis worsened. Both exercise and dobutamine induced ST-segment elevation, but dipyridamole did not. There was no significant difference in the degree of ST-segment elevation between the patients with and without myocardial ischemia or dyskinesis formation. Exercise induced a higher ST-segment elevation in patients with myocardial viability than those without (0.17+/-0.09 mV vs 0.09+/-0.07 mV, p<0.05). Exercise-induced ST-segment elevations correlated with dobutamine-induced ST-segment elevations (p<0.01), changes in heart rate (p<0.05) and systolic blood pressure (p<0.05). In conclusions, stress-induced ST-segment elevation does not correlate with either myocardial ischemia or stress-induced dyskinesis, but may be associated with myocardial viability.

Cardiotonic Agents↗
PubMed2001

Dietary manipulations of body fat-reducing potential of conjugated linoleic acid in rats.

To study whether the body fat-reducing potential of conjugated linoleic acid (CLA) could be increased through dietary manipulations, the effects of the combination of CLA with different proteins, fats, and sesamin were examined in rats. Male rats were fed diets containing 1% CLA or linoleic acid (LA) in combination with different proteins (20% of casein or soybean protein), fats (7% perilla oil or soybean oil) and 0.2% sesamin (SES) for 3 or 4 weeks. When the dietary fat source was soybean oil, CLA, as compared with LA, significantly reduced weights of epididymal and perirenal adipose tissues, irrespective of the dietary protein sources. However, the highest reducing effect was shown when soybean protein was given as a protein source. SES stimulated the reduction of epididymal and perirenal adipose tissue weights in both protein diets. In contrast, CLA increased the weight of brown adipose tissue, and SES further increased it in combination with soybean oil but not with perilla oil. No effect of dietary manipulation was observed on serum leptin and TNF-alpha levels. Thus, the body fat-reducing potential of CLA can be increased by an appropriate combination with food factors that may stimulate fatty acid beta-oxidation.

Adipose Tissue↗
PubMed2001

Chicken erythrocyte pyrimidine 5'-nucleotidase: purification and characterization of the subclass I enzyme.

Nucleotidase activities resembling subclass I and subclass II of human pyrimidine 5'-nucleotidases (P5N) were detected in chicken red blood cells (RBCs). In chicken RBCs from untreated controls, the activity of the subclass II enzyme was about one third of that of subclass I enzyme, whereas that ratio was approximately 5:1 in rat or human RBCs. The subclass I activity in chicken RBCs was increased 5- to 6-fold upon erythropoietic induction by phenylhydrazine administration, but the subclass II activity did not increase under these conditions. The subclass I enzyme was purified to near homogeneity. Its molecular mass was about 35 kDa as estimated by gel filtration and SDS-polyacrylamide gel electrophoresis. Its N-terminal 12 amino acids, PEFQKKTVHIKD, were also determined. The catalytic properties of the subclass I enzyme were very similar to those of the human enzyme with regard to substrate (preferential hydrolysis of CMP, dCMP, UMP), Km values, optimum pH, and metal ion requirements. Antibodies against chicken P5N subclass I were raised in rats. The chicken P5N-I as well as the rat P5N-I proteins could be detected by antibodies in Western blot analyses, but not the P5N-II proteins. These findings indicate that P5N subclass I may have an important function in chicken erythropoiesis.

5'-Nucleotidase↗
PubMed2001

Sampling methods and residential factors affecting formaldehyde concentration in indoor air.

Formaldehyde (HCHO) is the most serious residential pollutant. In order to evaluate residential HCHO levels, two sampling methods have been recommended; one is a 30 minute sampling in a closed room, and the other is a 24 hour sampling with an ordinary lifestyle routine. The aim of this report was to clarify the difference between the HCHO levels obtained by the two sampling methods. Residential air in 58 rooms was sampled for 30 minutes by an active sampling method more than 5 hours after residents closed windows, and by a passive sampling method for 24 hours with an ordinary lifestyle routine. The HCHO concentration with the 30 minute sampling was 0.118+/-0.065 ppm (range: 0.034-0.295 ppm) and 36 rooms (62%) exceeded the Japanese guideline value of 0.08 ppm, while 5% were higher than 0.25 ppm. The HCHO concentration with the 24 hours sampling was 0.053+/-0.039 ppm (range: 0.02-0.167 ppm) and only 13 rooms (22%) exceeded 0.08 ppm. The relationship between the concentrations obtained by the two methods was linear. However, the level with the 24 hour sampling significantly reduced with prolonged window opening time, meaning that occupants made an effort to reduce the usual exposure to about 40% of the exposure in a closed room by opening windows in order to escape from irritation. Since major adverse effects of HCHO are irritation and sensitization, the occasional peak concentration must be focused. In order to evaluate residential HCHO levels, measurement in a closed room is recommended even if people are living there.

Air Conditioning↗
PubMed2001

Seromucous cells in human sublingual glands: examination by immunocytochemistry of lysozyme.

This study examined the occurrence and morphological features of serous-type cells in human sublingual gland, using immunocytochemistry for lysozyme. Lysozyme-positive cells usually formed demilunes and occasionally their own acini. They were also found among cells of an intercalated duct and in its immature acinus consisting of a small number of secretory cells. All these serous cells could be classified as seromucous cells because they simultaneously revealed reactivity for mucus, i.e., a periodic acid-Schiff (PAS) and a periodic acid-thiocarbohydrazide-silver proteinate (PA-TCHSP) reaction under the light- and electron-microscope, respectively. Immunogold labeling of lysozyme in the seromucous cells was distributed on variously sized secretory granules. These usually possessed a single electron-dense spherule in an electron-lucent matrix, while granules of a homogenous structure were also present. Lysozyme-positive cells filled with large, lucent secretory granules could hardly be morphologically distinguished from the lysozyme-negative mucous cells; they corresponded to "intermediate" cells designated under the light microscope. All "immature" secretory cells with only a few secretory granules were also lysozyme-positive seromucous cells. The present study demonstrated that the seromucous cells in the human sublingual glands conform closely with those in the human labial glands (MIYAZAKI et. al., 1998).

Adolescent↗
PubMed2001

Experimental ammonia-free phosphate-bonded investments using Mg(H2PO4)2.

In previous study, we found that Mg(H2PO4)2 instead of NH4H2PO4 was available as a binder material for phosphate-bonded investments and possibly could be used to develop the phosphate-bonded investment without ammonia gas release. The purpose of the present study was to develop the experimental ammonia-free phosphate-bonded investments by investigating suitable refractories. Mg(H2PO4)2.nH2O and MgO were prepared as a binder. Cristobalite and quartz were selected as refractories. The power ratio of MgO/Mg(H2PO4)2.nH2O was set constant at 1.2 according to our previous findings. Fundamental properties of dental investment such as strength, manipulation and expansion were evaluated. Using cristobalite as the refractory material, further investigations were performed. The refractory/binder ratio was definitely effective. The increase of this ratio led to low mold strength and large mold expansion. The present findings suggested that C5 was desirable for dental investment.

Ammonia↗
PubMed2001

Involvement of protein kinase C-epsilon in signal transduction of thrombopoietin in enhancement of interleukin-3-dependent proliferation of primitive hematopoietic progenitors.

We studied the effect of thrombopoietin (TPO) on interleukin-3 (IL-3)-dependent bone marrow cell colony formation of mice to clarify the role of protein kinase C (PKC) in the signal transduction of TPO for the proliferation of primitive hematopoietic progenitors. TPO alone hardly yielded colonies. However, TPO in combination with IL-3 increased colony numbers synergistically from 2- to 4-fold, compared with those supported by IL-3 alone. Serial observation of colony development showed that TPO may hasten the appearance of colonies by shortening the dormant period (G(0)) of primitive progenitors. Immunocytochemical studies on PKC isoforms in progenitor cells stimulated with TPO have revealed that the expression pattern of PKC-epsilon is changed, but not that of PKC-alpha, -beta, -gamma, -delta, or -zeta. Selective PKC inhibitors, such as calphostin C and GF 109203X, and PKC-epsilon-specific translocation inhibitor peptide abrogated the enhancing effect of TPO on IL-3-dependent colony formation and the changes in the intracellular expression pattern of PKC-epsilon. These data taken together suggest that TPO has a direct effect on primitive progenitors and enhances IL-3-dependent colony formation, at least partly through the activation of PKC-epsilon.

Animals↗
PubMed2001

[Radiation therapy for painful bone metastases; aiming at optimal treatment schedules].

PURPOSE: To evaluate the pain relief obtained by radiation therapy for painful bone metastases, with a special regard to general condition. MATERIALS AND METHODS: Between June 1998 and May 2000, 54 patients with 86 painful bone metastases were treated with radiation therapy whose effects could be evaluated for a minimum period of 6 months or until death. Treatment schedules were 3 Gy/fraction/day (30-36 Gy/10-12 fractions) in usual cases (61 lesions), 4-8 Gy/fraction/day (8-20 Gy/1-5 fractions) in patients with a poor general condition (9 lesions), and 2 Gy/fraction/day (40-50 Gy/20-25 fractions) in lesions with a large radiation field (16 lesions). RESULTS: Complete pain relief without medication (CR) was achieved in 40 lesions (47%). Significant predictors for CR were primary site (p = 0.0003), performance status (p = 0.0060), pain score (p = 0.0190), narcotic score (p < 0.0001), and prognosis (p < 0.0001), but no difference was found in CR among treatment schedules. No evidence of severe radiation-induced complication was seen. CONCLUSION: General condition (performance status and prognosis) has an influence on pain relief. Compared with the daily 2 Gy protocol, the daily 3 Gy protocol has the advantage of shorter treatment time. The treatment schedule should be assessed in patients with a large radiation field and/or poor general condition. Especially for the patients with poor general condition, combined pain medication should be considered.

Adult↗
PubMed2001

[The present situation and the prospect of pain control in this country and other countries].

It is thought that the pain control is tried naturally in a lot of countries, but it is distress to know detailed fact of the present situation and the prospect. Nerve block therapy developed really in Japan is felt so that it is understood in Southeast Asia than the U.S.A. and West Europe. But in late years, it is thought as revision on nerve block began in Europe and America various countries. Recently, mechanisms of pain becoming clear, but administration of NSAIDs to every pain that was wrong therapy are still continued. In the pain treatment in every country, drug developed based on mechanism of pain and central analgesics will become center in the near future.

Americas↗
PubMed2001

[Aeromonas species infection with severe clinical manifestation in okinawa, Japan -association with gas gangrene-].

We experienced two patients having Aeromonas species infection with severe clinical manifestations. The one patient was a 15-year-old high school girl student, who had been healthy in her school life, was admitted to the hospital with a sudden onset of left thigh muscle pain and swelling. She subsequently went into septic shock and died one day after admission. Pathological examination on autopsy revealed massive gas formation, skin bullas and ulcers, and extensive severe soft tissue damage throughout the body. Also, all the specimens, including brain, liver, spleen, thigh muscle, and blood in cardiac cavity, were positive for A. veronii biovar sobria. The other patient was 35-year-old man, who suffered from multiple bone fractures during the work in the harbor. One day after admission, he became febrile and went into septic shock. With the presumptive diagnosis of sepsis and gas gangrene, amputation of left thigh was performed. The exudate and aspirate of the amputated portion were repeatedly positive for A. hydrophila. Through the surveillance in Okinawa, Kagoshima, Miyazaki, and Kumamoto Prefectures, a total of 426 isolates from blood cultures were collected in the period from August, 1999 to February, 2000. Of these, 14 isolates (3.3%) were the species of Aeromonas. Of 14 isolates of Aeromonas, 13 were reported from Okinawa and the remaining one was from Kumamoto. Most patients had underlying diseases, particularly liver diseases including liver cirrhosis. The mortality rate was extremely high at 62.5%, and the patients died in short terms after blood culture became positive. With these, Aeromonas species infection is unique to Okinawa, and positive blood culture for Aeromonas species potentially indicates a high-risk, particularly among the patients with underlying diseases.

Adolescent↗
PubMed2001

[A case of ankylosing spondylitis associated with pulmonary aspergillosis and amyloidosis].

A 56-year-old man was admitted because of diarrhea, cough, weight loss, and disturbance of consciousness. He had been diagnosed as having ankylosing spondylitis at 18-years old. The spondylitis progressed until there was complete rigidity of the spine including the neck, hip and knee joints. Human leukocyte antigen (HLA) B27, which has been characteristic of ankylosing spondylitis, was also present in this case. A chest radiograph showed pleural thickness and a cavity in the right upper lobe; and a soft tissue mass and fluid level was found in the cavity. Aspergillus fumigatus was detected in the sputum and pulmonary aspergillosis was diagnosed. Biopsy of the colon revealed that a large interstitial amyloidosis. Despite the treatment of the patient's malnutrition and lung aspergillosis using amphotericin B, the clinical course was rapidly progressive and the patient died of respiratory failure due to lung aspergillosis. It is important to be aware of these rare complications, which are correlated with the prognosis in cases of ankylosing spondylitis.

Amyloidosis↗
PubMed2000

Expression of c-Ets1 is associated with malignant potential in endometrial carcinoma.

BACKGROUND: The protooncogene c-ets1 is a transcriptional factor that controls the expression of a number of genes involved in extracellular matrix remodeling. It might play a role in the regulation of physiologic processes such as cell proliferation and differentiation and also is associated with angiogenesis, cell migration, and tumor invasion. METHODS: To elucidate the involvement of c-Ets1 in endometrial carcinogenesis, the authors analyzed serial frozen sections for c-Ets1 protein expression in 20 cases of endometrial carcinoma and 20 cases of normal endometria by fluorescent immunohistochemistry. The authors analyzed the relation between the percentages of c-Ets1 stained cells and patient characteristics including histologic grade, surgical stage, presence of invasion to greater than one-half myometrium, presence of vascular involvement, presence of lymph node metastasis, and clinical outcome. RESULTS: In the normal endometria, c-Ets1 was weakly detected at the luminal surface of endometrial glands in both the proliferative and secretory phases. Most of the c-Ets1 proteins were found in the cytoplasm and partly in the nucleus of endometrial carcinoma glands, and also in fluid secreted from endometrial carcinoma glands. Moreover, c-Ets1 was strongly expressed in the head portion of papillary carcinoma tissues that invaded the stroma. c-Ets1 expression was associated significantly with histologic grade (P < 0.005), the presence of invasion to greater than one-half myometrium (P < 0.001), surgical stage (P < 0.005), and vascular involvement (P = 0.009). CONCLUSIONS: The authors' results show that c-Ets1 expression in endometrial carcinoma correlates with the malignant potential of this tumor.

Endometrial Neoplasms↗
PubMed2000

Comparison of activation process of platelets and neutrophils after coronary stent implantation versus balloon angioplasty for stable angina pectoris.

The pathophysiologic features of stent-induced cellular responses of platelets and leukocytes have not been established. This study was designed to clinically investigate the activation of platelets and neutrophils after coronary stenting and to identify its effects on the long-term results of coronary stents. Forty-eight consecutive patients with left anterior descending coronary artery disease indicating coronary intervention were randomly assigned to either a balloon angioplasty group or a coronary stent group. Flow cytometric analysis demonstrated that the transcardiac gradient (the value of coronary sinus blood minus the value of peripheral blood) of platelet surface expression of CD62P (p < 0.001) and CD63 (p < 0.01) increased immediately after coronary stenting, but increased less significantly immediately after balloon angioplasty (CD62P, p < 0.01; CD63, p < 0.05). These increases were persistently observed after coronary stenting but transiently after balloon angioplasty alone during a 48-hour observation period after the procedures. The gradient for neutrophil surface expression of CD11b increased, and that of CD62 L decreased 48 hours after coronary stenting (CD11b, p < 0.001; CD62 L, p < 0.05), but these changes showed less significance 48 hours after balloon angioplasty alone (CD11b, p < 0.05; CD62 L, p = NS). The gradients 48 hours after the procedures for both CD62P (r = 0.39, p < 0.05) and CD11b (r = 0.44, p < 0.01) were independently correlated with the late loss in the stent group, whereas the correlation was seen only for CD11b (r = 0.38, p < 0.05) in the balloon angioplasty group. Both platelet and neutrophil activation was greater after coronary stenting than after balloon angioplasty. Cellular interactions between platelets and neutrophils may be related to the progression of neointimal proliferation leading to restenosis after coronary stent implantation.

Angina Pectoris↗