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Biomedical subjects

T Owaki

Publications and source records attributed to T Owaki.

At least 19 recordsLinked to original sources
PubMed2000

Endothelial cells potentiate phagocytic killing by macrophages via platelet-activating factor release.

The immunomodulatory function of endothelial cells (EC) includes the initiation of leukocyte margination, diapedesis, and activation through the upregulation of various cell surface-associated molecules. However, the effect that EC have on the phagocytic function of neighboring monocytes and macrophages is less well described. To address this issue, microvascular EC were cocultured with murine peritoneal macrophages, first in direct contact, then in a noncontact coculture system, and macrophage phagocytosis and phagocytic killing were assessed. The presence of increasing concentrations of EC resulted in a dose-dependent increase in macrophage phagocytic killing. This stimulatory effect was inhibited in a dose-dependent manner by the pretreatment of macrophage/EC cocultures with WEB-2086 or CV-6209, specific platelet-activating factor (PAF)-receptor antagonists, but not by anti-tumor necrosis factor-alpha, anti-interleukin (IL)-1alpha, or anti-IL-1beta. Furthermore, the effect was reproduced in the absence of EC by the exogenous administration of nanomolar concentrations of PAF. Microvascular EC potentiate macrophage phagocytic killing via the release of a soluble signal; PAF appears to be an important component of that signal.

Animals↗
PubMed1999

Automated determination of 5-fluorouracil and its metabolite in urine by high-performance liquid chromatography with column switching.

We report a quantitative assay of 5-fluorouracil (FU) and its metabolite, 5-fluorodihydrouracil (FDHU) in human urine by used a column-switching high-performance liquid chromatographic method. The analyses were carried out using a molecular exclusion column for sample purification, and a cation-exchange column for separation. Each sample required only 40 min to analyze, and required no preparation other than filtration. Linearity was verified up to 1000 nmol/ml (r > 0.993). The recovery of FU was 96-101%; recovery of FDHU was 96-105%. The imprecision (RSD) for FU (10-100 nmol/ml) was < 1.5%, same-day (n = 5), and < 1.8%, day-to-day (n = 5). The imprecision (RSD) for FDHU (10-100 nmol/ml) was < 3.2%, same-day (n = 5), and < 4.0%, day-to-day (n = 5). The detection limits were, respectively, 0.1 nmol/ml. We measured FU and FDHU in urine of seven cancer patients after oral administration of FU. The cumulative quantity ratio of the FDHU and FU (FDHU/FU) excreted in their urine within 120 min after FU administration was a constant value in all seven patients. Based on these results, we believe that our method provides a useful tool for evaluating FU metabolism.

Breast Neoplasms↗
PubMed1998

Endothelial cells potentiate oxidant-mediated Kupffer cell phagocytic killing.

Phagocytosis and killing of circulating organisms by Kupffer cells (KCs) are discrete, important components of host defense. However, the killing mechanism(s) are not fully understood, and the potential role of adjacent nonparenchymal cells such as hepatic endothelial cells has not been defined. Rat KCs -/+ an hepatic endothelial cell enriched cellular fraction (HECEF) were incubated with Candida parapsilosis and assayed for phagocytosis and phagocytic killing by validated fluorochromatic vital staining. The role of reactive oxygen metabolites in KC phagocytic functions was examined by inhibition with superoxide dismutase and/or catalase. Diphenyleneiodonium and allopurinol were used to examine the potential roles of NADPH oxidase and xanthine oxidase, respectively, in generating these toxic oxidants. Coculture with HECEF increased KC phagocytic activity (from 75% to 88%) and candidacidal activity (from 20% to 31%). Superoxide dismutase, catalase, diphenyleneiodonium, or allopurinol caused inhibition of candidacidal activity, but did not affect phagocytosis, and did not block the potentiation of phagocytosis or of killing caused by coculture with HECEF. Reactive oxygen intermediates generated by both NADPH oxidase and xanthine oxidase-dependent pathways are important in KC killing of Candida parapsilosis. In vitro, KC phagocytosis and killing are potentiated (via a non-oxidant-mediated mechanism) by coculture with a preparation of hepatic non-parenchymal cells composed primarily of endothelial cells.

Allopurinol↗
PubMed1997

Study of needlestick accidents and hepatitis C virus infection in healthcare workers by molecular evolutionary analysis.

In the five-year period between 1989 and 1993, 87 needlestick accidents occurred among healthcare workers at our hospital. Thirty-seven (43%) of these needlestick accidents involved blood contaminated with hepatitis C virus (HCV), and two of them (5.4%) led to the occurrence of hepatitis C infection. Case 1 was a 43-year-old nurse who was accidentally injured by a needle contaminated with blood from a patient who had cirrhosis and hepatocellular carcinoma due to hepatitis C. Acute hepatitis C occurred after five weeks and HCV RNA was positive after eight weeks. Case 2 was a 33-year-old nurse who was injured by a needle contaminated with blood from a patient who had chronic hepatitis C. Liver function was normal at 11 days after the accident. However, hepatitis C was diagnosed 21 months later after she had successfully given birth to her baby. The nucleotide sequence of the HCV E2/NS1 region was determined in the two patients and the needlestick victims, and phylogenetic trees were constructed by molecular evolutionary analysis. On the basis of these trees, transmission of HCV could be confirmed in both cases. This method of analysis may be useful for confirming the transmission of HCV even long after the event.

Adult↗
PubMed1995

[7 years of annual mass screening for colorectal cancer in office workers--usefulness of 3-day RPHA method].

Immunological fecal occult blood test have been proved to be useful in the mass screening for colorectal cancer. Since 1986, we have started annual mass screening by the use of 3-day RPHA method and medical questionnaire for office workers over 40 yr old. During 7 yr, 261 out of 5386 examinees were testing positive for fecal occult blood, a test positive rate was 4.8% and 12 colorectal cancer (7: early, 5: advanced) were found. Among 12 cases, 10 were detected by positive results of RPHA test and 2 by questionnaires of symptoms or family history. The sensitivity and specificity of this method were calculated at 83.3% and 95.3% respectively. But as for advanced cancers, the sensitivity of this method was 100%. 75% of patients with colorectal cancer were over 55 yr old. The predictive value of positive test (PV) were much more higher in subjects with 2 or 3 times test positive (high risk group: PV = 14.3%) than in subject with only 1 time test positive (low risk group: PV = 0.6%). So it is considered to be reasonable that the high risk group (24% of total test positive) should be immediately undergone further examinations (Ba. enema or colonoscopy), and the low risk group should be undergone re-examinations of 3-day RPHA method. By this system, almost 50% of further examinations will be reduced. In conclusion, 3-day RPHA method with this further examination system is reasonable and efficient for screening of colorectal cancer in office workers, considering the high reliability in cancer detection and decreased further examinations.

Colorectal Neoplasms↗
PubMed1984

Clinical application of transvenous mitral commissurotomy by a new balloon catheter.

A new balloon catheter was developed which allows mitral commissurotomy without thoracotomy. The procedure has been successful in five of the six patients with mitral stenosis so treated. In the remaining patient, the procedure could not be performed because of technical difficulties. The balloon is reinforced with a nylon micromesh and its shape changes in three stages, depending on the extent of inflation. It is inserted from the saphenous vein into the mitral orifice transseptally, fixed across the mitral orifice with partial inflation, and finally inflated to full its extent, separating the fused commissures by its expansile force. After the procedure, catheterization revealed a significant reduction in the mean diastolic pressure gradient across the mitral valve without resultant mitral regurgitation in each patient. Two-dimensional echocardiograms showed a marked to moderate degree of dilatation of the mitral orifice in each patient. All five patients are well with remarkable clinical improvements 2 to 16 months after the procedure.

Adult↗
PubMed1982

[Noninvasive evaluation of cardiac involvements and left ventricular function in schoolchildren with the history of mucocutaneous lymph node syndrome].

Mucocutaneous lymph node syndrome (MCLS) in the young has been known to have coronary aneurysms, and then it has been recently suspected as a cause of premature atherosclerosis and cardiomyopathy. Thirty-three schoolchildren who suffered from MCLS were studied to evaluate cardiac involvements and left ventricular function using two-dimensional (2-D) echocardiograms and submaximal stress test. Fifteen normal schoolchildren were studied as normal control. All these MCLS children were asymptomatic and had no significant findings in routine chest X-ray and electrocardiographic examinations. According to submaximal stress test, 8 cases showed a J type ST depression of only 0.5--1.0 mm, and there were no positive cases. Using 2-D echocardiograms, the left coronary artery was detected in 85% and the right coronary in 27%. One case showed an aneurysm of the left coronary artery. However, none of them showed abnormal left ventricular wall motion or the wall motion abnormality compatible with cardiomyopathy. There were no significant differences between MCLS and normal control in ejection fraction, mean VCF, diastolic descent rate of the anterior mitral valve, D/S ratio of the left ventricular wall, and Weissler's index (PEP/ET). These findings suggested that 1) most of MCLS schoolchildren do not have obvious cardiac involvement and their left ventricular function is within normal limits, 2) because of its low sensitivity, submaximal stress test is not so useful in screening coronary lesions, and 3) the 2-D echocardiogram works not only in detecting coronary aneurysms but also in evaluating left ventricular function.

Adolescent↗
PubMed1981

[Tricuspid valve motion and tricuspid valve ring size in normals and patients with atrial septal defect (author's transl)].

To investigate the normal configuration of the tricuspid valve and the normal size of the tricuspid valve ring, 17 normals, 20 patients with atrial septal defect, 4 patients with tricuspid valve prolapse, and 41 patients with various diseased conditions were studied by cross-sectional echocardiography. The tricuspid valve ring diameter in atrial septal defect was judged to be increased in comparison with that of normals. All the patients with tricuspid valve prolapse exhibited an excessive systolic ballooning of the leaflets toward the right atrium. However, a systolic ballooning of the leaflets alone was frequently observed in normals and many other conditions. Therefore, we conclude that cross-sectional echocardiography has some clinical limitations in the differential diagnosis between tricuspid valve prolapse and normals.

Adult↗
PubMed1981

[Cross-sectional and M-mode echocardiographic diagnosis of vegetative endocarditis in the right-sided heart (author's transl)].

M-mode and cross-sectional echocardiograms of 3 cases with vegetative endocarditis in the right-sided heart were reported. The location of vegetative lesions was the tricuspid valve in one, the parietal band of the right ventricle and chordae tendinae in one, and the pulmonary artery wall in the remaining patient. Ruptured chordae tendinae were observed in the patient with tricuspid valve vegetation. M-mode echocardiography detected vegetative lesions in all patients. However, the precise size and location of these lesions, and a complication of the destructive process were not evaluated by M-mode echocardiography. On the other hand, cross-sectional echocardiography not only documented the presence but also assessed the morphologic characteristics of the lesions, since this technique provides spatial orientation concerning moving structures. Furthermore, ruptured chordae tendineae in the patient with tricuspid valve vegetation was correctly estimated. However, the lesions should be differentiated from other conditions including a localized calcified lesion, abscess and thrombus. In conclusion, cross-sectional echocardiography in combination with M-mode echocardiography is recommended in diagnosing vegetative lesions in the right-sided heart.

Adolescent↗
PubMed1979

Cross-sectional echocardiographic diagnosis of coronary artery aneurysms in patients with the mucocutaneous lymph node syndrome.

Real-time cross-sectional echocardiographic studies revealed the presence of coronary artery aneurysms in five patients with mucocutaneous lymph node syndrome. These lesions appeared as circular echo-free spaces with clearly-defined borders in sites corresponding to angiographically proven aneurysms. In 15 normal subjects who were studied only by noninvasive methods, and in 17 who had normal coronary arteriograms (including eight with the mucocutaneous lymph node syndrome), we found no similar echo findings. The aneurysms were in both right and left coronary arteries in three patients, and were confined to the left side in two. The mucocutaneous lymph node syndrome is an increasingly common condition in Japan which may be fatal due to myocardial infarction occurring in a setting of coronary aneurysm with thrombosis. Therefore, the ability to demonstrate coronary aneurysms noninvasively is of prognostic and potentially therapeutic value in this inadequately understood syndrome.

Adult↗
PubMed1979

Noninvasive diagnosis of pseudoaneurysm of the left ventricle.

The echocardiographic, scintigraphic, angiocardiographic and autopsy correlations in a patient with left ventricular pseudoaneurysm are presented. Interruption of the echo of the left ventricular wall and radioisotope image of pseudoaneurysm and its communication channel are demonstrated for the first time. The striking similarity of the radioisotope image to the angiographic image is noted. This study suggests that echocardiography has capability to visualize left ventricular wall defects, such as the perforation seen in this case and radioisotope ventriculography is equivalent to the invasive contrast technique. Both of the methods seem to be safe and specific for the diagnosis of left ventricular pseudoaneurysm.

Aged↗