Biomedical subjects

A Ohta

Publications and source records attributed to A Ohta.

315 records · Page 18Linked to original sources

PubMedDate not supplied

Role of G-protein-coupled adenosine receptors in downregulation of inflammation and protection from tissue damage.

Inappropriate or prolonged inflammation is the main cause of many diseases; for this reason it is important to understand the physiological mechanisms that terminate inflammation in vivo. Agonists for several Gs-protein-coupled receptors, including cell-surface adenosine purinergic receptors, can increase levels of immunosuppressive cyclic AMP in immune cells; however, it was unknown whether any of these receptors regulates inflammation in vivo. Here we show that A2a adenosine receptors have a non-redundant role in the attenuation of inflammation and tissue damage in vivo. Sub-threshold doses of an inflammatory stimulus that caused minimal tissue damage in wild-type mice were sufficient to induce extensive tissue damage, more prolonged and higher levels of pro-inflammatory cytokines, and death of male animals deficient in the A2a adenosine receptor. Similar observations were made in studies of three different models of inflammation and liver damage as well as during bacterial endotoxin-induced septic shock. We suggest that A2a adenosine receptors are a critical part of the physiological negative feedback mechanism for limitation and termination of both tissue-specific and systemic inflammatory responses.

Adenosine↗

PubMedDate not supplied

Clinical evaluation of pulmonary 3D time-of-flight MRA with breath holding using contrast media.

OBJECTIVE: Our goal was to evaluate the clinical utility of pulmonary 3D TOF MRA using a contrast medium and breath holding. MATERIALS AND METHODS: To determine an optimal imaging time in a pilot study, 30 sequential axial images were obtained for each of 18 patients by using a turbo fast low angle shot sequence immediately after a bolus injection of 5 ml Gd-DTPA. MRA consisted of five sequential MR scans performed using a 3D fast imaging with steady-state precession sequence on 13 patients. The imaging start time after a bolus injection of 10 ml Gd-DTPA was determined from the results of the pilot study. We hoped that the acquisition of the center of k-space of the first MRA was matched to the period of maximum effect of the first pass bolus for the pulmonary arteries. RESULTS: In a pilot study on average, pulmonary artery signal intensities were relatively high from 10.4 to 20.7 s after the contrast medium injection. The MR angiograms obtained at the optimal time were superior to those that followed. All pulmonary trunks and the right and left main pulmonary arteries were accurately recognized. MRA had a sensitivity of 80.0%, a specificity of 95.0%, and an accuracy of 94.5% for the detection of segmental artery stenosis or occlusion. Abnormal vessels were visualized in both patients with pulmonary sequestration. CONCLUSION: Pulmonary 3D TOF MRA using breath holding and a contrast medium is useful in demonstrating proximal pulmonary vasculature and pulmonary sequestration.

Adult↗

PubMedDate not supplied

The association of Behçet's disease with myelodysplastic syndrome in Japan: a review of the literature.

OBJECTIVE: [corrected] To determine the clinical characteristics of patients with myelodysplastic syndrome (MDS)-associated Behçet's disease (BD) in Japan. METHODS: 54 Japanese cases of MDS-associated BD obtained from the literature and from our own clinical experience were reviewed. The clinical features of MDS-associated BD were compared with those of the 1991 nationwide BD survey in Japan. RESULTS: In MDS-associated BD, the average age at onset was 42.6 years, which was 6.9 years later than for all BD patients; females developed disease more frequently than males (male: female ratio = 0.80). In MDS-associated BD cases, the occurrence of eye lesions was significantly lower, the frequency of intestinal lesions was markedly higher, and the rate of HLA-B51 positivity was lower than that in all BD. BD and MDS developed nearly simultaneously in 49.0% of cases; BD preceded MDS in 31.4% of the cases. The distribution of the age at BD onset showed two peaks, one in the 3rd decade and the other in the 6th decade. Females were more likely to develop younger-onset disease, while men were more likely to develop older-onset MDS-associated BD. Furthermore, in the older-onset group, BD was diagnosed together with or after the diagnosis of MDS, while half of the younger-onset group developed BD earlier than MDS. CONCLUSION: MDS-associated BD patients form a distinct subset of patients. There may, in fact, be two major groups of MDS-associated BD patients based on age, gender, and temporal relationship of the two diseases.

Adolescent↗

PubMedDate not supplied

Ventricular fibrillation. A complication and hazard of transcatheter obliteration of the renal artery with absolute ethanol in dogs.

Selective renal artery embolization with absolute ethanol was performed without balloon occlusion in a series of 11 healthy mongrel dogs. Electrocardiogram, blood ethanol level, heart rate, and blood pressure of the aorta and pulmonary artery were monitored. Ventricular extrasystoles and/or ventricular fibrillation occurred in six of the 11 dogs, to which absolute ethanol in doses ranging from 0.09 to 0.40 ml/kg was administered. In three of these six animals, the electrocardiograms showed only ventricular extrasystoles after intra-arterial bolus injection of absolute ethanol at doses of less than 0.15 ml/kg and subsequent recovery to a normal sinus rhythm. Ventricular fibrillation subsequent to ventricular extrasystoles immediately after intra-arterial injection of absolute ethanol at doses of more than 0.18 ml/kg occurred in three. In five of eight dogs that survived after alcohol injection in this series, a severe hypertensive response was observed. Absolute ethanol has the potential hazard of causing ventricular arrhythmia. Thus, careful observations should be undertaken in clinical therapeutic application of this agent, particularly in the absence of balloon occlusion, absolute ethanol should never be used without monitoring the electrocardiogram.

Animals↗

PubMedDate not supplied

The influence of celomic membranes and a tunnel between celomic cavities on cancer metastasis in poultry.

The roles of celomic membranes and celomic structures in preventing cancer metastasis were examined. The relationship between a tunnel in the peritoneal cavity of hens and the cancer metastasis was also investigated. A tunnel between the right and left dorsal hepatic cavities was found in almost half of healthy hens. The tunnel was also found in 17% of hens with cancer. Neoplastic cells were detected in the ascitic fluid of 79% of hens with effusions. Metastasis was most severe in the intestinal peritoneal and left dorsal hepatic cavities, whereas the right dorsal hepatic cavity showed the least involvement. Severe inflammatory responses were found within the metastatic membranes, resulting in an increase in their thickness. In tumor-bearing hens, crevasse-like splits were present within the membranes at the layers of loose connective tissues. It appears that the splits prevent further invasion by the cancer cells. There were no successful lesions on the inner surfaces of air sacs. It is suggested that the tunnel in the peritoneal cavity enhances cancer metastasis. We also conclude that the celomic membranes and their structure in hens retard the spread of cancer by functioning as a barrier against direct spread of the cancer cells.

Animals↗

PubMedDate not supplied

Estradiol receptors and ovalbumin in adenocarcinoma of hens.

The origin of adenocarcinomas in 10 hens was studied using an assay for estradiol receptors (ERs) and ovalbumin. ERs were found in nine tumors, and ovalbumin was present in eight tumors. Hormonal regulation of this cancer is indicated, and it is suggested that the origin of the tumor is probably the glands of the oviduct.

Adenocarcinoma↗

PubMedDate not supplied

Pulmonary MR angiography: a comparison of 2D and 3D time-of-flight.

OBJECTIVE: To compare two-dimensional (2D) time-of-flight (TOF) MR angiography and three-dimensional (3D) TOF MR angiography for visualization of pulmonary arteries and to determine whether pulmonary veins can be viewed selectively. MATERIALS AND METHODS: Imaging was performed using a 1.5 T superconducting MR system with a body coil. Three kinds of 2D TOF MR angiography were compared in four normal volunteers: using a 2D fast low angle shot (FLASH) without cardiac gating and both with and without breath-holding and using a T2-weighted TurboFLASH with cardiac gating and breath-holding. Two-dimensional TOF MR angiography using a T2-weighted TurboFLASH with cardiac gating and breath-holding and 3D TOF MR angiography using fast imaging with steady precession with neither cardiac gating nor breath-holding were compared in four other normal volunteers. Two-dimensional TOF MR venography with a presaturation pulse to suppress artery signals was evaluated in another four normal volunteers. RESULTS: Three-dimensional TOF MR angiography appeared to be better than 2D TOF MR angiography for delineating pulmonary arteries in the volunteers. The third order branches of peripheral pulmonary veins were distinguishable on 2D TOF MR venography using a presaturation pulse. CONCLUSION: Three-dimensional pulmonary TOF MR angiography is useful in demonstrating pulmonary arteries whereas 2D TOF MR venography with a presaturation pulse is useful in showing pulmonary veins.

Adult↗

PubMedDate not supplied

Preliminary study of pulmonary three-dimensional time-of-flight MR angiography with breath-holding using a contrast medium.

Pulmonary three-dimensional (3D) time-of-flight (TOF) MR angiography with breath-holding using a paramagnetic contrast medium and a 1.5 Tesla superconducting MR system was performed on a volunteer and five patients with hilar or mediastinal tumors in order to visualize the main pulmonary arteries. Six MR scans (one before and five after a Gd-DTPA injection) were obtained using fast imaging with a steady-state precession (FISP) sequence while the subjects held their breath. The acquisition time was 21 seconds, and images were obtained every 30 seconds. In the normal volunteer, the pulmonary MR angiogram obtained in the first postcontrast scan was successful in visualizing the main pulmonary artery, and its right and left branches to the level of the lobar branches. In the five patients, at the first postcontrast scanning, the pulmonary arteries had higher signal intensities than the surrounding structures. Therefore, during this imaging period, most tumors could be clearly distinguished from vessels. In images made much later after contrast medium injection, the pulmonary arteries could not be distinguished from the others. Pulmonary 3D TOF MR angiography with breath-holding using a contrast medium is very useful in demonstrating pulmonary vessels and tumors.

Adult↗

PubMedDate not supplied

[Relationship between the experience of steroids side effects and noncompliance with oral steroids treatment in collagen disease patients].

PURPOSE: To analyze the relationship between the experience of side effect and the compliance with oral steroids drug treatment of the patients in Collagen Disease Clinic. METHODS: A questionnaire survey through interview was conducted on 165 outpatients with various collagen disease at Saga Medical School Hospital. RESULTS: 94 patients (57%) had a history of noncompliance to the steroids drug. 49 patients (52.1%) adventitiously had forgotten to take the steroids as ordered and 45 patients (47.9%) intentionally had regulated their steroids dose or had discontinued the steroids drug treatment. Over 80% of the patients had experienced side effects of the steroids. The patients who experienced one or more of the following side effects, osteoporosis, bone fractures, menstrual disorders, moon face, central obesity, alopecia, acnelike eruption, manic-depressive state, and insomnia, intentionally regulated, or discontinued the steroids therapy. In addition, the patients who were not made cognizance about side effects of the steroids by their physicians and nurse tended to noncompliance group. CONCLUSION: To increase the compliance rate with oral steroids drug treatment, we must make conscious efforts to inform the patients on the condition of their medical states, the efficacy of the prescribed drugs, and the side effects and risk concerning discontinuation of the steroids. It is Also necessary to establish "Drug information and counseling day" in outpatient Department.

Anti-Inflammatory Agents↗