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Biomedical subjects

S Homma

Publications and source records attributed to S Homma.

394 records · Page 22Linked to original sources
PubMedDate not supplied

Intravascular ultrasound imaging of the Heartmate 1000 IP left ventricular assist device.

Left ventricular assist devices are increasingly used as a bridge to transplantation in patients with end-stage cardiac disease. Potential complications of these devices include thromboembolism and infection. Because conventional cardiac diagnostic techniques cannot be used to obtain an image of the interior of a left ventricular assist device, we assessed the ability of intravascular ultrasonography to obtain an image of the interior of the Heartmate 1000 IP left ventricular assist device. Feasibility of intravascular ultrasound imaging was initially demonstrated in vitro on a left ventricular assist device immersed in water. Five soft rubber masses were then placed in the device intake port adherent to the wall, and their images were obtained by intravascular ultrasonography. Excellent correlation between actual size and size as measured by intravascular ultrasonography was noted (long-axis, r = 0.98, short-axis, r = 0.89). After the device was implanted in two calves, intravascular ultrasound imaging was performed in vivo in the animals. The catheter was easily advanced through the device, and excellent images were obtained. In conclusion, intravascular ultrasonography can easily be used to obtain an image of the left ventricular assist device interior and can accurately assess the presence and size of abnormal masses inside the device. Intravascular ultrasonography may be clinically useful in evaluating cases of thrombus or vegetation related to left ventricular assist devices.

Animals↗
PubMedDate not supplied

Detection of multiple papillary fibroelastomas of the tricuspid valve by transesophageal echocardiography.

A 66-year-old man without symptoms, referred for the treatment of moderate hypertension, was found to have a right atrial mass by two-dimensional echocardiography. On transesophageal echocardiography two masses were detected on the tricuspid valve, the first one on the posterior leaflet and the second smaller one on the anterior leaflet. These findings were confirmed at surgery. Histologic analysis revealed that the masses represented papillary fibroelastomas.

Aged↗
PubMedDate not supplied

MR imaging of spinal cord in Devic disease.

A 20-year-old man with typical features of Devic disease was studied with magnetic resonance (MR) demonstrating sequential changes of the spinal cord from swelling to atrophy. A good correlation between neurological findings and MR imaging was documented.

Adult↗
PubMedDate not supplied

Transesophageal echocardiography in stroke.

Fifteen to twenty percent of all ischemic strokes are of cardioembolic origin. Since the introduction of transesophageal echocardiography (TEE) in 1976, its clinical application in the diagnosis of cardioembolic stroke has expanded greatly. Comprehensive literature has accumulated showing TEE as an invaluable tool for the diagnosis of cardioembolic stroke because it allows superior visualization of established embolic stroke risk factors (apical thrombus, endocarditis) as well as the identification of newer factors (patent foramen ovale, aortic arch plaques, etc.). In this article, we summarize the present status of TEE in the diagnostic workup of stroke.

Aorta, Thoracic↗
PubMedDate not supplied

Marked atherosclerosis in a patient with familiar lecithin: cholesterol acyltransferase deficiency associated with end-stage renal disease and diabetes mellitus.

Familial lecithin:cholesterol acyltransferase (LCAT) deficiency is a rare genetic disorder of the lipid metabolism caused by the absence of LCAT activity in plasma. It is not generally accompanied by atherosclerosis in spite of low high-density lipoprotein cholesterol levels nor by diabetes mellitus. However, reports of long-term follow-up or autopsy findings are rare, and the true incidence of atherosclerosis in LCAT deficiency is not clear. We report on the long-term observation of a patient with familial LCAT deficiency who developed renal failure, diabetes mellitus, and marked atherosclerosis. The patient died of sepsis from foot ulcers 7 years after starting hemodialysis and 13 years after the diagnosis. Marked atherosclerosis characterized by medial calcification in small arteries was observed at autopsy. The genesis of the atherosclerosis seemed to be on the basis of a combination of factors.

Arteriosclerosis↗
PubMedDate not supplied

Effect of phosphate deprivation on enzymes of the cyclic adenosine monophosphate metabolism in rat proximal convoluted and proximal straight tubules.

Phosphate deprivation causes a resistance to the phosphaturic effect of parathyroid hormone (PTH). The present study determined whether acute phosphate deprivation alters basal or stimulated activities of key enzymes of the cyclic adenosine monophosphate (cAMP) metabolism in microdissected proximal convoluted and proximal straight tubules, since blunted cAMP levels in these proximal subsegments might account for refractoriness to the effect of PTH on phosphate reabsorption in the proximal convoluted and proximal straight tubule segments. In the proximal convoluted tubules of rats fed a normal-phosphate diet (NPD), PTH increased the adenylate cyclase activity by tenfold. In the proximal convoluted tubule of rats fed a low-phosphate diet (LPD), PTH also increased the adenylate cyclase activity by tenfold. In addition, forskolin increased the adenylate cyclase activity to levels similar to PTH in the proximal convoluted tubule of rats fed NPD or LPD. In the proximal straight tubule of rats fed NPD, PTH resulted in an approximately fivefold increase in adenylate cyclase activity. In the proximal straight tubule of rats fed LPD, PTH resulted in a fourfold increase in adenylate cyclase activity. The forskolin-stimulated adenylate cyclase activity was markedly decreased (46%) in the proximal straight tubule of phosphate-deprived rats. The cAMP-phosphodiesterase activity in the proximal convoluted tubule was significantly increased by 26% in phosphate-deprived rats. The cAMP-phosphodiesterase activities in the proximal straight tubules from rats fed NPD or LPD were similar. We conclude that distinct differences in key enzymes of cAMP metabolism exist in the proximal convoluted and proximal straight tubule subsegments. Further, phosphate deprivation affects the cAMP-phosphodiesterase and adenylate cyclase activities differently in these nephron subsegments.(ABSTRACT TRUNCATED AT 250 WORDS)

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMedDate not supplied

Antitumor effect of immunizations with fusions of dendritic and glioma cells in a mouse brain tumor model.

The authors studied antitumor immunity conferred by fusions of dendritic and glioma cells in a mouse brain tumor model. Previous immunization with fusion cells (FCs) prevented tumor formation on challenge with glioma cells in the flank or in the brain. Efficacy was decreased when studies were performed in mice depleted of CD8+ cells. In a treatment model, FCs were injected subcutaneously after tumor development in the brain. The administration of FCs alone had limited effects on survival of mice bearing brain tumors. Importantly, however, administration of FCs and recombinant interleukin-12 (rIL-12) remarkably prolonged the survival of mice with brain tumors. Cytotoxic T lymphocyte activity against glioma cells from immunized mice was also stimulated by coadministration of FCs and rIL-12 compared with that obtained with FCs or rIL-12 alone. These data support the therapeutic efficacy of combining FC-based vaccine therapy and rIL-12.

Animals↗
PubMedDate not supplied

Diagnosis of patent foramen ovale with transesophageal echocardiography in a patient supported with a left ventricular assist device.

Intracardiac right-to-left shunting through a patent foramen ovale is a known cause of arterial hypoxemia. We present a case report of a patient supported with a left ventricular assist device who had significant right-to-left shunting as visualized with transesophageal echocardiography. When the device was turned off, no further shunting occurred and arterial hypoxemia resolved. Our report is the first visual representation of the anatomy of a patent foramen ovale in a patient supported with a left ventricular assist device.

Adult↗
PubMedDate not supplied

Coronary angiography in smokers undergoing evaluation for lung transplantation: is routine use justified?

Many patients referred for lung transplantation have a history of smoking. For the exclusion of the possibility of asymptomatic coronary artery disease, these patients undergo coronary angiography as part of their preoperative evaluation. The usefulness of this approach remains unknown. We reviewed the records of all smokers referred for lung transplantation who underwent coronary angiography (n = 77). Nine patients (12%) had significant coronary artery disease; six (8%) of these patients had their clinical management altered because of findings on angiography. Eight of nine patients with coronary artery disease (89%) and all of the six patients (100%) whose management was altered had coronary artery disease risk factors other than a history of smoking; therefore, no patient with clinically significant coronary artery disease had history of smoking as the only risk factor. The presence of other coronary artery disease risk factors was significantly associated (p < 0.0001) with the positive findings on angiography. A nonsignificant trend toward older age was found, and a higher proportion of male patients existed in the group with coronary artery disease. Routine angiography for all patients with a history of smoking referred for angiography is unjustified. A subset of patients with high risk identified primarily by the presence of additional coronary artery disease risk factors may benefit from routine angiography.

Coronary Angiography↗