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T Katsuda

Publications and source records attributed to T Katsuda.

9 recordsLinked to original sources
PubMed1993

Effect of cadmium on osteogenesis within diffusion chambers by bone marrow cells: biochemical evidence of decreased bone formation capacity.

The biological and biochemical effects of cadmium administration on bone marrow in rats were examined. When young adult rats were administered cadmium (Cd) repeatedly at a dose of 750 micrograms/kg body wt for up to 4 weeks, metallothionein mRNA was detected by a gene expression analysis in their bone marrow at 2 weeks after the first Cd administration, though the amounts were lower than those in liver. To determine the direct effect of cadmium on bone formation, the potential of Cd-treated bone marrow cells and demineralized bone matrix (DBM) to form bone and cartilage was assessed using a diffusion chamber (DC) in vivo, by histological examination, and by biochemical parameters such as alkaline phosphatase (ALP) activity, total calcium and phosphorus content, and the bone-specific vitamin K-dependent Gla-containing protein (BGP) content, relative to mineralization. Diffusion chambers were inoculated with DBM and bone marrow cells from either Cd-treated or nontreated rats (control) and were then implanted subcutaneously into syngeneic nontreated rats. The accumulation of BGP in DCs with Cd-treated bone marrow was significantly lower than that in control DCs. Unlike in control DC, a peak of ALP activity did not occur at 4 weeks postimplantation in DC implants inoculated with Cd-treated bone marrow; the ALP activity and calcium content in these implants were also significantly lower than those of the control bone marrow-containing chambers at the early stage of implantation. Histological examinations of chambers with Cd-treated marrow showed a decreased area of cartilage and bone foci compared with those in control chambers. These findings suggest that Cd administration inhibits the osteoblastic and chondroblastic differentiation pathway in bone marrow through direct effects on these cells.

Animals↗
PubMed1991

A diaphragmatic compensating filter for hepatic angiography.

To enhance the clarity of angiographic images, a diaphragmatic compensating filter (DCF) covering the sub-phrenic portion was constructed. The required shape of a DCF for a high optical density part of the angiograms was determined by the distribution limit of the outline of the diaphragms, but the shape of the low optical density part could not be specified. The smallest tolerance of a DCF for the respiratory motion of a diaphragm was 13.2 mm at the film. Thus, a DCF was effective in more than 95.8% of angiograms. Our clinical results showed remarkable improvement in those images. The clinical areas between radiographic images with and without a DCF were improved by more than 27% according to an image analysis system. Therefore a DCF is indispensable in conventional hepatic angiography and digital subtraction angiography. In addition, only one type of a DCF is possible for use in combination with lateral compensating filters.

Hepatic Artery↗
PubMedDate not supplied

Reducing motion artifacts during hepatic DSA.

In hepatic digital subtraction angiography, artifacts caused by diaphragmatic motion can interfere with the correct diagnosis of hepatic lesions. This article describes the feasibility of using the exhalation holding method in reducing diaphragmatic motion artifacts in hepatic DSA. The authors compared respiratory holding methods in 30 patients who underwent hepatic DSA. They performed a blind comparison of images to assess diaphragmatic motion artifacts. Results showed the images obtained by the exhalation holding method were superior to those obtained by the inhalation holding method in 20 out of 30 series (66.7%).

Adult↗
PubMedDate not supplied

Using compensating filters to reduce radiation dose.

The study described in this article explores the role of compensating filters in reducing radiation exposure. Radiation exposure levels with and without filters were compared in skull radiographs, hepatic angiographs and one-shot full-length lower extremity radiographs. Absorbed doses were measured with and without a skull filter in a phantom at a depth of 5 cm. Results showed that filters reduced exposure by 29% in skull radiographs, 47% in hepatic angiographs and 80% in one-shot full-length lower extremity radiographs. Absorbed doses were reduced by more than 26% in the skull phantom in the filtered area. To reduce patient dose, the filters were positioned between the x-ray tube and the patient.

Absorption↗
PubMedDate not supplied

Types of diaphragmatic motion during hepatic angiography.

To determine the types and causes of diaphragmatic motion during hepatic angiography, the authors used transarterial cut-film portography (TAP) to study movement of the diaphragm during breath-holding. Thirty-three TAP sequences were studied, and the patients' diaphragmatic motions were classified into four categories according to the distance their diaphragms moved. Results showed that the diaphragm was stationary in 33% of the TAP studies, while perpetual motion occurred in 15% of the studies, early-phase motion occurred in 12% and late-phase motion occurred in 40%. Ten sequences showed diaphragmatic motion of more than 10 mm, with eight sequences showing caudal motion and two showing cranial motion. This article discusses the cause of diaphragmatic motion during breath-holding for hepatic angiography and presents suggestions to reduce motion artifacts during the exam.

Adult↗
PubMedDate not supplied

Reducing misregistration of mask image in hepatic DSA.

When performing hepatic digital subtraction angiography, misregistration of the mask image can cause artifacts that obscure pathology. For this article, researchers analyzed the breath expiration times of 59 patients and found that expiration times ranged from 1.8 seconds to 6 seconds. Thirty DSA series were obtained taking into account the patient's breath expiration time, and 35 series were obtained without taking the expiration time into consideration. Artifacts were detected in 20% of the DSA series where expiration time was taken into consideration and in 42.9% of series where it was not (p < 0.05). The research showed that misregistration of the mask image during hepatic DSA can be reduced by starting the exposure at the end of breath expiration.

Adult↗