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Biomedical subjects

S Tamaki

Publications and source records attributed to S Tamaki.

At least 19 recordsLinked to original sources
PubMed1992

Plasma thrombomodulin as a marker of vascular disorders in thrombotic thrombocytopenic purpura and disseminated intravascular coagulation.

Plasma thrombomodulin (TM) levels were significantly elevated at disease onset in patients with thrombotic thrombocytopenic purpura (TTP) and disseminated intravascular coagulation (DIC), but was not in those with essential thrombocythemia and idiopathic thrombocytopenic purpura. However, in patients with TTP and DIC, TM levels decreased significantly after they achieved complete remission. In both TTP and DIC patients, plasma TM levels at onset in those with poor prognosis were higher than that in those with good prognosis. Among DIC patients, the plasma TM level was higher in those with organ failure than in those without, but there were no differences among patients with various underlying diseases associated with DIC. It is speculated that the plasma TM level reflects damage to vascular endothelial cells or organ failure and that it is useful in assessing prognosis for patients with DIC and TTP.

Biomarkers↗
PubMed1992

Plasma cytokine levels in thrombotic thrombocytopenic purpura.

Plasma cytokine levels were examined in 13 patients with thrombotic thrombocytopenic purpura (TTP). Auto-antibodies, platelet-associated immunoglobulin G, and platelet aggregating factor were detected in many of these patients and high-molecular-weight bands of von Willebrand factor multimers were reduced in 9 of 10 patients examined. Complete remission (CR) was attained in 7 of the 13 patients, but 6 died. Tumor necrosis factor (TNF), Interleukin (IL)-1 beta, IL-6, and soluble IL-2 receptor showed marked increases at onset and decreased at CR. The prognosis tended to be poor in patients with increased IL-6 and soluble IL-2 receptor levels. These findings suggest that immunological mechanisms, such as the activation of macrophage, are involved in the pathogenesis of TTP and are reflected in the plasma cytokine levels.

Adolescent↗
PubMed1992

Vitronectin in liver disorders: biochemical and immunohistochemical studies.

The concentration of plasma vitronectin was determined and compared with various parameters of liver function including the blood coagulation system in patients with liver diseases. The severity of cirrhosis was graded according to Child's criteria and compared with the plasma vitronectin level. Furthermore, the distribution of vitronectin in the liver of patients with liver diseases was studied by light and electron microscopy using the indirect immunoperoxidase method. The plasma vitronectin level was low in all liver disease groups as compared with the healthy controls. The difference from the controls was significant in patients with hepatocellular carcinoma and decompensated cirrhosis. Moreover, the plasma vitronectin level was positively correlated with the levels of serum cholinesterase, albumin, plasma alpha 2 plasmin inhibitor-plasmin complex and the prothrombin time and results of the hepatoplastin test. Plasma vitronectin decreased with increasing severity of cirrhosis according to Child's criteria. These results suggest that the plasma vitronectin level is a useful parameter of hepatic synthetic function in patients with liver diseases; it may also reflect the severity of cirrhosis. Light microscopy revealed vitronectin in the area of focal necrosis and the portal tracts in the liver of patients with acute viral hepatitis, in the area of piecemeal necrosis in the liver of patients with chronic hepatitis and along the area of fiber deposition in the liver of patients with cirrhosis. Immunoelectron microscopy showed vitronectin in the rough endoplasmic reticulum of hepatocytes. Moreover, vitronectin was seen around inflammatory cells, endothelial cells, Ito cells and hepatocytes in the perisinusoidal area near focal necrosis and piecemeal necrosis and on collagen fibers.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Environmental biochemistry of arsenic.

Microorganisms are involved in the redistribution and global cycling of arsenic. Arsenic can accumulate and can be subject to various biotransformations including reduction, oxidation, and methylation. Bacterial methylation of inorganic arsenic is coupled to the methane biosynthetic pathway in methanogenic bacteria under anaerobic conditions and may be a mechanism for arsenic detoxification. The pathway proceeds by reduction of arsenate to arsenite followed by methylation to dimethylarsine. Fungi are also able to transform inorganic and organic arsenic compounds into volatile methylarsines. The pathway proceeds aerobically by arsenate reduction to arsenite followed by several methylation steps producing trimethylarsine. Volatile arsine gases are very toxic to mammals because they destroy red blood cells (LD50 in rats; 3.0 mg kg-1). Further studies are needed on dimethylarsine and trimethylarsine toxicity tests through inhalation of target animals. Marine algae transform arsenate into non-volatile methylated arsenic compounds (methanearsonic and dimethylarsinic acids) in seawater. This is considered to be a beneficial step not only to the primary producers, but also to the higher trophic levels, since non-volatile methylated arsenic is much less toxic to marine invertebrates. Freshwater algae like marine algae synthesize lipid-soluble arsenic compounds and do not produce volatile methylarsines. Aquatic plants also synthesize similar lipid-soluble arsenic compounds. In terrestrial plants, arsenate is preferentially taken up 3 to 4 times the rate of arsenite. In the presence of phosphate, arsenate uptake is inhibited while in the presence of arsenate, phosphate uptake is only slightly inhibited. There is a competitive interaction between arsenate and phosphate for the same uptake system in terrestrial plants. The mode of toxicity of arsenate is to partially block protein synthesis and interfere with protein phosphorylation but the presence of phosphate prevents this mode of action. There appears to be a higher affinity for phosphate than arsenate with a discriminate ratio of 4:1. It is estimated that as much as 210 x 10(5) kg of arsenic is lost to the atmosphere in the vapor state annually from the land surface. The continental vapor flux is about 8 times that of the continental dust flux indicating that the biogenic contribution may play a significant role in cycling of arsenic. It has not been established whether volatile arsenic can be released by plants. Further studies are needed to determine mass balances in the rate of transfer (fluxes) of arsenic in the environment.

Animals↗
PubMed1992

Revascularization for coronary ostial stenosis in Takayasu's disease with calcified aorta.

A case in which a patient with stenoses of the right and left coronary ostia and heavy calcification of the aorta caused by Takayasu's disease was successfully treated by coronary artery bypass grafting is presented. The aortic ends of the two grafts were attached to a xenopericardial patch, which was sutured into the ascending aorta. This technique can be done without fine sutures, which are required for proximal anastomosis of a vein graft, and may reduce the risk of ostial stenosis.

Anastomosis, Surgical↗
PubMed1992

Amplification of plasmid (L factor) DNA and increased production of a plasmid gene product (gamma-interferon) in mouse L cells.

It has previously been reported that composite DNAs derived from L factor, a polyoma-related mammalian plasmid, can be established in several mouse cell lines after transfection. Here, we report that the copy number of a plasmid composite DNA consisting of L factor, pBR DNA, dihydrofolate reductase (dhfr) gene, and gamma-interferon (gamma-IFN) gene was increased more than 10-fold after two successive adaptations of the plasmid-bearing mouse L cells to increasing concentrations of methotrexate (MTX), an inhibitor of dhfr. The structure of the amplified L factor plasmid remained intact during prolonged cell culture, but the copy number remained to be amplified only when the selective pressure (presence of MTX in the medium) has been exerted during the culture. Cells bearing the amplified plasmid produced a higher level of gamma-IFN compared with the original clone, which was likely to be derived from the plasmid gamma-IFN gene amplified along with L factor and the dhfr gene.

Animals↗
PubMed1992

Value of three-dimensional surface display of brain perfusion imaging. Comparison with tomographic imaging.

The diagnostic ability of a three-dimensional surface display of I-123 IMP brain scintigrams and tomographic images was compared in 12 patients who underwent I-123 brain tomography for cerebral cortical hypoperfusion. Foci of decreased accumulation were independently diagnosed by four radiologists, first with transaxial images, second with three-dimensional images, and finally with both images subjectively compared for the purpose of diagnosing the existence, localization, and extent of lesions. Six different lesions (0 to 3 lesions/radiologist) were found only on the transaxial images, but 30 different lesions (1 to 14 lesions/radiologist) were found on the three-dimensional images. In 9 out of 12 cases, the three-dimensional images were regarded as superior for evaluating the extension of the lesion and for lesion existence and lesion localization in 5 out of 12 (P less than 0.05). In conclusion, a three-dimensional display of an I-123 IMP brain tomogram is superior to tomographic images in diagnosing the extent of cerebral cortical hypoperfusion. However, the display is not superior to tomographic images for diagnosing the existence and localization of hypoperfusion.

Amphetamines↗
PubMed1992

A model to simulate the haemodynamic effects of right heart pulsatile flow after modified Fontan procedure.

The effect of pulsatile pulmonary flow after the modified Fontan procedure was examined in a model that simulated the right heart. An inlet overflow tank (preload), axial pulsatile pump, Wind-Kessel model (afterload), and an outlet overflow tank were connected in series. The standard conditions were flow 2.00 l/min with 12 mm Hg preload pressure, 3.0 Wood units resistance, and an outlet overflow tank pressure at 6 mm Hg. The pump rate was set at 80 beats/min. The simulated pulmonary arterial pressure and pulmonary flow waves produced by this model closely resembled those obtained from patients who had undergone the modified Fontan procedure. All variables except the preload were fixed and changes in pulmonary flow were examined at preload pressures of 8, 12, 15, and 17 mm Hg. As the peak pulmonary arterial pressure increased so did pulmonary flow, until it was greater than during the non-pulsatile state. Because the afterload of this model was fixed, this result suggests that there was a concomitant decrease in resistance. This model indicates that pulsatile pulmonary blood flow is likely to have a beneficial effect on the pulmonary circulation after the modified Fontan procedure.

Blood Pressure↗
PubMed1992

Importance of hydrolysis of amino acid moiety in water-soluble prodrugs of disodium cromoglycate for increased oral bioavailability.

The relationship between physicochemical properties and oral absorption was investigated in prodrugs for the oral delivery of disodium cromoglycate (DSCG). To improve the lipophilicity of DSCG, various lipophilic moieties were introduced into the twin carboxyl groups. However, this did not lead to improved oral absorption in rabbits because of loss of water solubility, in spite of improved lipophilicity. Water-soluble prodrugs, in which an amino acid was introduced into a hydroxy group by ester linkage in addition to ethyl residues at twin carboxyl groups of DSCG, were synthesized and examined for oral absorption in rabbits and rats. The oral absorption of these prodrugs was affected by the species of amino acids introduced as a water-soluble moiety. Therefore, we examined the relation between the oral absorption of water-soluble prodrugs and the hydrolysis rate of the amino acid moiety. A good linear correlation was obtained between the oral absorption and the hydrolysis rate constant catalyzed by digestive enzymes, trypsin or alpha-chymotrypsin. It was thus concluded that the amino acid moiety of water-soluble prodrugs must be rapidly hydrolyzed to a permeable lipophilic prodrug still possessing the ethyl moiety at twin carboxyl groups in the small intestinal tract for good oral absorption.

Administration, Oral↗
PubMed1992

Percutaneous transluminal coronary angioplasty for patients with unstable angina pectoris.

Percutaneous transluminal coronary angioplasty (PTCA) was successful in 91% of 76 patients with unstable angina pectoris refractory to pharmacological treatment. However, the rate of acute occlusion and reocclusion was rather high (95). Restenosis developed in 56.5% of successful cases after initial PTCA, and 29 patients underwent 2nd, and nine 3rd PTCA. Most refractory unstable angina can be controlled by PTCA, which may require repeating in some patients.

Adult↗
PubMed1992

Coronary risk factors used to predict coronary artery disease by logistic regression analysis.

Risk factor analysis in coronary artery disease was conducted in 303 patients who underwent coronary arteriography to identify associations between personal characteristics and the prevalence of coronary heart disease. Age, sex, obesity, smoking, alcohol intake, hypertension, diabetes mellitus, serum uric acid, total cholesterol, LDL- and HDL-cholesterol, triglyceride, and atherogenic indices were statistically analyzed. All 13 variables were first compared between patients with positive and negative ergonovine tests. Only total cholesterol was significantly different, while significant differences in age, sex, history of diabetes, total cholesterol, LDL- and HDL-cholesterol, triglyceride and atherosclerotic indices were observed between patients with and without organic coronary artery stenosis. A multivariate analysis was performed, and the resulting equation was tested using the remaining patients. Logistic analysis of all 13 variables identified 5 (age, sex, diabetes mellitus, LDL- and HDL-cholesterol) which accounted for the differences between patients with and without significant coronary artery disease and that were validated in the test group. The sensitivity for prediction of coronary artery disease was 75.8%, specificity 68.5%, and predictive accuracy 71.5% in the test group. Thus, risk factor analysis appears to be very valuable in screening subjects with high-risk organic coronary stenosis and in optimizing the preventive and therapeutic modalities, but not in predicting vasospastic subjects.

Cholesterol↗
PubMed1992

[Application of ultrasonography in chest diseases--usefulness of ultrasonography and physiologic evaluation of low pressure vascular system].

Air and bones, which limit echo penetration to the lesion, are the major components of the thorax. Recently, however, there have been many reports concerning the valid application of ultrasonography for evaluation of chest diseases. In this paper, we report the usefulness of ultrasonography to analyze thoracic lesions based on our experience. Generally, ultrasonography is a method providing high resolution and real-time images. Using these characteristics, we tried to obtain physiological information concerning the hemodynamics of the right heart system. We addressed the results of our studies using ultrasonography as follows; 1) relationship between ventilatory change of IVC and central venous pressure, 2) estimation of pulmonary arterial pressure by measuring the size of the pulmonary artery, 3) dynamic changes of SVC configuration.

Hemodynamics↗
PubMed1992

[Idiopathic thrombocytopenic purpura associated with pregnancy].

We examined 14 patients (18 cases) with idiopathic thrombocytopenic purpura (ITP) during pregnancy at our department. ITP, which had improved, recurred during pregnancy in 4 cases while it developed for the first time during pregnancy in 10 cases. In the other 4 cases, pregnancy occurred in the course of ITP. Although a normal infant was born in 14 cases, 3 stillbirth and a premature infant was observed in 4 cases. Six deliveries had some toxemia of pregnancy. A transient decrease in neonatal platelets was observed in 4 of 14 cases and mother's platelets count was less than 40 X 10(3)/microliters in the 4 cases. Although antinuclear antibody, Coomb's test and antiphospholipid antibody were positive in some cases, these were not markedly related to clinical course or neonatal platelets count. Eleven cases were treated with glucocorticoids, high dose gamma globulin or platelets transfusion, but 11 cases were not treated. Since ITP is frequently observed during pregnancy and may be some risk factor for pregnancy, treatment of ITP is important during pregnancy.

Adult↗
PubMed1992

[Surgical treatment of aortic root abscesses using a hand-made valved xenopericardial conduit].

A case is described in which a new treatment was taken to eradicate an aortic root abscess in a 56-year-old man with aortic prosthetic valve endocarditis. Debridement of all apparently infected tissue created left ventricular-aortic discontinuity, involving the orifice of the right coronary artery. A conduit of a diameter of 23 mm was made by hand with a glutaraldehyde preserved xenopericardial graft. A 21 mm St. Jude Medical prosthetic valve was sewn in it at 2 cm to its edge. The hand-made valved conduit was used to reconstruct the left ventricular outflow tract and aortic root. A saphenous vein graft was anastomosed end-to-side to the right coronary arterial system and to the conduit distal to the prosthetic valve. The aortography revealed no aortic regurgitation nor abnormalities of the conduit, such as aneurysm formation, and the coronary arteriography showed a functioning graft 5 months after surgery.

Abscess↗
PubMed1992

[Surgical treatment of acquired tricuspid stenosis].

There is no definitive surgical procedure for acquired lesions of the tricuspid valve (TV). From Feb, 1978, through March, 1990, the surgical treatment for the organic lesions of TV was performed in 10 patients, repair in 6 and TV replacement in 4. TV was repaired by commissurotomy, annuloplasty or valvuloplasty, or combination of them. When residual significant tricuspid regurgitation (TR) and/or stenosis (TS) was detected by intraoperative pulsed Doppler echocardiography after reparative procedures, TV was replaced. Follow-up periods ranged from 1 to 12 years (mean, 45.3 months). There was no early death, and late death was noted in one patient 32 months after operation. Preoperatively, 7 patients were in NYHA class IV and 3 in class III. Out of survivors, 7 are in class I and 2 in class II because of progression of mitral stenosis or coronary artery disease. Following surgery, the patients exhibited significant decrease in the cardiothoracic ratio (69.3 +/- 7.2 to 56.9 +/- 6.4%; p less than 0.01) and in the mean right atrial pressure (11.4 +/- 3.6 to 8.6 +/- 3.1 mmHg; p less than 0.05). The postoperative right ventriculography showed mild to moderate TR in 3 of 6 patients who underwent TV repair. In conclusion, TV repair could be a reasonable procedure for the organic TV lesions, although careful follow-up is recommended for residual TR.

Adult↗