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Biomedical subjects

O Suzuki

Publications and source records attributed to O Suzuki.

At least 199 records · Page 11Linked to original sources
PubMed1990

Biocompatibility of zirconia dispersed hydroxyapatite ceramics.

Because of the lack of adequate strength and toughness, hydroxyapatite (HA) ceramic can not be used for a substitute for a bone and joint despite its excellent affinity for the bone. The present authors have succeeded in producing a new type of HA ceramic containing zirconia. This new ceramic material is superior to ordinary HA ceramic in quality and exceeds compact bone in bending strength and fracture toughness. The Young's modulus was about 3-4 times greater than that of compact bone. The new ceramic material contained either 1.6 or 50% of zirconia by volume and was produced using a special technique to disperse the metal dioxide. In order to assess their affinity for the bone, the new ceramic materials were implanted into rabbit femurs. Sections of the bones removed at different times after operation were prepared without decalcification and subjected to optical microscopy, scanning electronmicroscopy (SEM), and electron-probe X-ray microanalyser (EPMA). The formation of direct chemical bonds with the bone was seen without intervening membrane. Thus, the new ceramic material was shown to have an excellent affinity for the bone, comparable to that of ordinary HA ceramic.

Animals↗
PubMed1990

Rapid isolation of some antiepileptic hydantoins and their analogues with Sep-Pak C18 cartridges and capillary gas chromatography with splitless injection.

A simple and rapid method for isolation of seven antiepileptics (2 hydantoin, 2 oxazolidin, and 3 suximide derivatives) from urine and plasma is presented. Urine and plasma (1 ml) samples containing seven antiepileptics were mixed with distilled water (4 ml), and the sample solution was poured into a pretreated Sep-Pak C18 cartridge; this was washed with water and chloroform/methanol was passed through it to elute the antiepileptics. The eluate was mixed with isoamyl acetate and evaporated under a stream of N2. The drugs were detected by gas chromatography with fused silica capillary columns, splitless injection and flame ionization detection. Separation of the seven antiepileptics from each other and from impurities was satisfactory with the use of an SPB-1 capillary column. The detection limit for the seven antiepileptics with the present method was 0.1-1.0 microgram/ml urine or plasma. The recovery of the drugs from urine and plasma was more than 70% and 50%, respectively.

Anticonvulsants↗
PubMed1989

Determination of paraquat in raw and formalin-fixed tissues by electron spin resonance (ESR) spectroscopy.

ESR method was applied to determine paraquat levels in fresh and formalin-fixed tissues. Paraquat was converted to paraquat radical by adding sodium dithionite to tissue homogenates and detected by ESR. Paraquat levels of more than 0.2 micrograms/ml homogenate could be quantified with 0.1 ml of the homogenate. The use of manganese ions for standardization of paraquat signal enabled much more accurate ESR measurements because this ion was quite stable and its signal did not overlap that of paraquat. Even with tissues fixed in formalin, tissues paraquat levels were measureable after removing formalin from the tissue extract. This fact was verified by studying two cases; the tissues were kept in formalin for 1.5 years in case 1 and for 6.5 years in case 2. In both cases, the paraquat contents in tissues were 0.02-0.08 micrograms/g. In this way ESR is one of the most suitable methods in determining low levels of paraquat in tissues even after they were preserved in formalin for a long time.

Adult↗
PubMed1989

Rapid isolation with Sep-Pak C18 cartridges and wide-bore capillary gas chromatography of some butyrophenones.

A simple and rapid method for isolation of five butyrophenones with Sep-Pak C18 cartridges from human samples, and their wide-bore capillary gas chromatography (GC), are presented. The GC was made by both flame ionization and electron capture detections. The drugs contained in alkaline samples were directly applied to the cartridges and eluted with chloroform/isopropanol (9:1). The recoveries with use of the cartridges were excellent for most drugs in both urine and plasma samples. We can recommend the Sep-Pak C18 cartridges for isolation of butyrophenones because of simplicity and rapidity, and also wide-bore capillary GC because of high sensitivity and low decomposition of drugs during passage through the column.

Antipsychotic Agents↗
PubMed1989

Semicarbazide-sensitive amine oxidase activity in catfish tissues.

1. Semicarbazide-sensitive amine oxidase activity was found in five tissues of the siluroid catfish, Parasilurus asotus, using benzylamine as substrate. It was highest in the intestine, followed by the liver and skin. 2. The apparent Km value and optimal pH for benzylamine in the intestine were 49.8 microns and 8.8, respectively. 3. Substrate specificity of the enzyme was tested in the intestine and the highest activity was found with beta-phenylethylamine, followed by tryptamine and benzylamine.

Amine Oxidase (Copper-Containing)↗
PubMed1989

Rapid isolation with Sep-Pak C18 cartridges and wide-bore capillary gas chromatography of some barbiturates.

A simple and rapid method for isolation of nine barbiturates with Sep-Pak C18 cartridges from human urine, plasma and whole blood, is presented; the detection of drugs was made by wide-bore capillary gas chromatography (GC) with flame ionization. The drug-containing samples, after mixing with dilute acid solution, were directly applied to the cartridges and eluted with either chloroform/methanol (9:1) or acetonitrile. Separation of the nine drugs was satisfactory with use of an intermediately polar HP-17 capillary column. Recoveries of most compounds were excellent for both chloroform/methanol and acetonitrile as elution solvents. However, backgrounds were cleaner and evaporation time was much shorter for the chloroform/methanol system. The present isolation method with use of Sep-Pak C18 cartridges and wide-bore capillary GC seem very useful in the fields of forensic chemistry, clinical toxicology and clinical pharmacology.

Barbiturates↗
PubMed1989

[Mass screening of cardiovascular disorders by two-dimensional echocardiography].

We used two-dimensional echocardiography (2-D echo) for the mass screening of 2,673 subjects for cardiovascular disorders (1,032 men, 1,641 women, aged 23-95 years with a mean age of 59), who lived in 12 rural areas in Japan. In 1,665 of the 2,673 subjects (62.3%), cardiac abnormalities were recognized. Three major abnormalities included sclerotic aortic (33.0%) and mitral valves (21.8%), and left ventricular (LV) hypertrophy (15.9%). Apparent pericardial effusion (54 cases), mitral valve prolapse (44 cases), and dilated cardiomyopathy (4 cases) were incidentally found in this study. Prevalence of the abnormalities insidiously increased with age (below 49 years: 39%, and above 80 years: 97%), and this was apparently higher in men than in women. The abnormal findings which were significantly higher in men were the sclerotic aortic valves, LV hypertrophy and dysfunction, the prevalence of which was particularly high in ages 40-79, but it became nearly equal beyond 80 years of age. These results may indicate a sexual difference in the influence of age on the cardiovascular system. It was concluded that 2-D echo is helpful for primary screening and prevention of cardiovascular disorders.

Adult↗
PubMed1989

[A case of mitral regurgitation from non-penetrating chest trauma].

An 18-year-old boy, with no evidence of cardiac murmurs in the past, was admitted to our hospital after steering wheel injury on Nov 22, 1987. He immediately became in shock state. Physical examination revealed a grade 3/6 apical holosystelic murmur and moist rales in lungs. Two-dimensional echocardiography showed a prolapsed anterior leaflet and a lot of pericardial effusion. He recovered soon after subxiphoid pericardiotomy, then we obtained bloody fluid of 200 microliters. In cardiac catheterization study, the pulmonary artery wedge pressure was elevated with a V-wave of 31 mmHg. Coronary angiogram, right ventriculogram, and aortogram were normal, but left ventriculography revealed grade 4 (Seller's) mitral regurgitation. Mitral valve replacement was performed with a Bjork-Shiley prosthesis on Feb 8, 1988. Anterior papillary muscle was in a white necrosis, but not ruptured. Mitral valve leaflets and chordae tendineae were intact. 12 cases of mitral regurgitation from non-penetrating blunt chest trauma were reported in Japan, but we first report a case of mitral regurgitation due to non-ruptured papillary muscle dysfunction.

Adult↗
PubMed1989

[Effect of RVAD for right heart failure involved with right ventricular infarction--especially studies of myocardial regional blood flow and epicardial mapping electrocardiography].

In recent years, the number of cases in which a ventricular assist device is required for serious heart failure not responding to conventional mechanical circulatory assistance, has been increasing. It should be pointed out, however, that the majority of the new device is to assist the left ventricle, and that the effect of right ventricular assist device (RVAD) has not been fully clarified yet. The effect of RVAD and intra-aortic balloon pumping (IABP) on right ventricular failure due to right ventricular infarction was studied in swine. Right ventricular infarction was made by means of right coronary artery ligation. After preparation of right ventricular infarction, both mean aortic pressure and cardiac output were reduced and elevated central venous pressure, increased right ventricular end-diastolic pressure, dilatation of right ventricular free wall, were noted and diagnosed as a cardiogenic shock due to acute right ventricular infarction. Right ventricular infarcted area was evaluated by epicardial mapping ECG and myocardial regional blood flow. It was found that in the cases using IABP, the effect of reducing the infarcted area due to diastolic augmentation was noted, but the effect on the right ventricular support was not satisfactory, while in the cases using RVAD, the right ventricular preload was reduced and the right ventricular stroke work was decreased, and the effect of reducing the infarcted area was observed. But hemodynamic effect of these method were not satisfactory, enough to assist recovery from cardiogenic shock.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Studies on frequency-dependent attenuation in the normal liver and spleen and in liver diseases, using the spectral-shift zero-crossing method.

This report presents results of studies using the spectral-shift zero-crossing method to measure frequency-dependent attenuation (FDA) in normal liver and spleen and in diseased liver. We developed a new system for attenuation analysis that calculated FDA in dB/cm/MHz according to the following equation: (formula: see text). Data are collected from the region of interest on the scan image. Graphite-gel phantoms of known attenuation value are used to create a high degree of accuracy in this new system. Mean attenuation of normal livers was 0.55 +/- 0.05 dB/cm/MHz, while that of normal spleen was 0.37 +/- 0.06 dB/cm/MHz. No correlation between FDA and age could be seen. FDA was 0.81 +/- 0.17 dB/cm/MHz in fatty liver, 0.63 +/- 0.13 dB/cm/MHz in liver cirrhosis, and 0.64 +/- 0.12 dB/cm/MHz in chronic hepatitis. These values are higher than those obtained from normal liver, while tumor masses in the liver (hepatocellular carcinoma, hepatoblastoma, hemangioma) and diffuse infiltration by malignant lymphoma produced lower than normal values, averaging 0.38 +/- 0.08 dB/cm/MHz.

Adolescent↗
PubMed1988

Positive and negative ion mass spectrometry of antiepileptic hydantoins and their analogs.

Positive ion electron impact (PIEI), positive ion chemical ionization (PICI), and negative ion chemical ionization (NICI) mass spectra of seven compounds of hydantoins and their analogs are presented; their probable fragmentation modes are also presented. In the PIEI mode, intensities of molecular ions differed according to different compounds. Cleavage at outsides of both carbonyl groups was commonly observed for all compounds. In the PICI mode, all compounds showed [M + 1]+ quasi-molecular ions constituting the base peaks. In the NICI mode, [M - 1]- quasi-molecular anions were the base peaks except for trimethadione and paramethadione. All negative spectra showed anions at m/z 42 due to [NCO]-; these peaks seem useful for screening of antiepileptics. An extraction procedure for the anti-epileptics from human urine or plasma, and their separation by gas chromatography (GC), are also presented to serve for their actual identification by GC/mass spectrometry.

Anticonvulsants↗
PubMed1988

Cryopreservation of rat blastocysts by vitrification.

Rat blastocysts equilibrated with vitrification solution (VS1), consisting of dimethyl sulfoxide, acetamide, propylene glycol, and polyethylene glycol were plunged directly into liquid nitrogen. The embryo suspension are solidified by an extreme elevation in viscosity of solution. The embryos are cryopreserved by vitrification without intra- and extracellular ice formation. The proportion of morphologically normal embryos after cooling and warming was 79% (117/149) and all (48/48) of the embryos cultured were developed to expanded or hatched blastocysts. Normal live young were obtained 41% of the time (28/69) after transfer of the cooled and warmed embryos to pseudopregnant recipients.

Animals↗
PubMed1988

In vitro inhibition of human platelet monoamine oxidase by phenothiazine derivatives.

Nineteen phenothiazines were tested for in vitro inhibition of human platelet type B monoamine oxidase (MAO). The inhibition potency was highly dependent on structures of their side chains. The inhibition was most potent for drugs with (hydroxyethyl-piperazinyl)propyl chains followed in decreasing order by those with (N-methylpiperazinyl)propyl, (2-dimethylamino-2-methyl)ethyl and 3-dimethylaminopropyl chains. Kinetic analyses were carried out for promazine, promethazine, perazine and perphenazine as representatives of each group; the four drugs showed competitive inhibition, and Ki values of 124, 31.4, 19.2 and 22.6 microM, respectively.

Blood Platelets↗
PubMed1988

Rapid quantitative analysis of paraquat by electron spin resonance spectroscopy.

A very simple and sensitive method for quantitative measurement of paraquat in plasma, urine and some drinks is described. The paraquat radical formed by its reduction can be detected by electron spin resonance spectroscopy (ESR) at room temperature without clean-up or concentration process of samples. The sensitivity limit is 0.1 microgram paraquat/ml and the required amount of sample is 100 microliter. The time needed for the measurement is within 10 min.

Beverages↗
PubMed1988

Determination of beta-phenylethylamine in catfish (Parasilurus asotus) tissues by gas chromatography/mass spectrometry.

1. beta-Phenylethylamine (PEA) was detected and quantitated in tissues of the catfish, Parasilurus asotus, by very specific and sensitive gas chromatography/mass spectrometry. 2. The selected ion monitoring was made with a strong quasi-molecular ion of the pentafluoropropionic derivative of PEA in the positive chemical ionization mode. 3. PEA was found in all tissues tested ranging from 2.8 to 38.2 ng/g wet wt tissue. It was highest in the spinal cord, followed by the skin, brain and intestine.

2-Hydroxyphenethylamine↗
PubMed1988

[2 surgically treated cases of adrenocortical carcinoma producing steroid hormones without endocrinological symptoms--case report and a review of cases in the Japanese literature].

We have experienced two male cases of an adrenocortical carcinoma that have produced steroid hormones without endocrinological symptoms. Both men were admitted to hospital because of an abdominal pain and left hypochondral tumors. In each case, an abdominal CT, an ultrasonogram and an angiogram demonstrated a left adrenal tumor, and levels of blood dehydroepiandrosterone sulfate, etiocholanolone, pregnenolone sulfate and urine 17 KS were elevated. The tumors were resected and the histology revealed that they were adrenocortical carcinomas. Postoperatively, the levels of their urine hormones returned to normal values, though in one man recurrence occurred a year later. Only 8 cases of an adrenocortical carcinoma that has produced steroids without specific endocrinological symptoms have been reported in Japan, and we also report on two cases herein.

17-Ketosteroids↗