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Biomedical subjects

Y Nagano

Publications and source records attributed to Y Nagano.

At least 127 records · Page 7Linked to original sources
PubMed1989

Persistent wedge-shaped low-density lesions on computed tomography of the kidneys without infarction.

A patient with acute lymphoblastic leukemia, who developed acute renal failure, was imaged by computed tomography (CT). Persistent wedge-shaped areas of low attenuation in the kidneys were shown by sequential scans but not areas of infarction were found at autopsy. This case suggests that a wedge-shaped low-density lesion on CT may occur not only in infarcted areas, but also in areas where patchy vasoconstriction occurs.

Acute Kidney Injury↗
PubMed1989

Induction of mRNA for low-density lipoprotein receptors in heterozygous Watanabe heritable hyperlipidemic rabbits treated with CS-514 (Pravastatin) and cholestyramine.

We administered CS-514, an inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase, alone and in combination with cholestyramine to heterozygous Watanabe heritable hyperlipidemic rabbits. This rabbit model for heterozygous familial hypercholesterolemia has hepatic low-density lipoprotein receptors that are assumed to be half as many as in normal rabbits. CS-514 alone lowered plasma low-density lipoprotein cholesterol levels by 50%, and in combination with cholestyramine, it lowered levels by 80%. The membrane-binding assay showed these drugs caused 1.5- and 1.8-fold increases in the number of hepatic low-density lipoprotein receptors, respectively. We also measured the amount of mRNA for low-density lipoprotein receptor by S1 nuclease protection assay in the same livers as above. These drugs induced mutant mRNA for the low-density lipoprotein receptor, which has an in-flame deletion of 12 nucleotides, as well as normal receptor mRNA. CS-514 alone produced a 1.8-fold increase in the amount of mRNA for the normal receptor and a 2.3-fold increase for the mutant mRNA, whereas CS-514 in combination with cholestyramine produced 1.9- and 3.1-fold increases, respectively. We conclude that CS-514 induces mRNA for the low-density lipoprotein receptor, subsequently increasing the receptor protein in the liver, and then reduces the levels of plasma cholesterol, and that the induction is augmented when the drug is administered in combination with cholestyramine.

Animals↗
PubMed1989

[Study on composite resin cores. Part 2. Effect of pressing composite resin].

In this study, we investigated effects of pressing in building composite resin cores on compressive strength, retention of prefabricated post and sealing ability. 1. Compressive strength increased by pressing in composite resin cores. 2. Prefabricated post to the retentive forces was not influenced by pressing, but increased when bonding agent was used. 3. Pressing was very effective to improve sealing ability of composite resin to tooth structure. 4. Sealing ability of light-cured composite resin was not influenced by pressing but by curing types of bonding agent.

Composite Resins↗
PubMed1989

[Study on gypsum hardener].

The purpose of this study was to search for an appropriate condition for shortening the treatment time of gypsum hardener, Plaster Aid. In order to keep the increased strength of plaster with this new hardener, compressive strength and dimensional change in various conditions of heating temperature, heating time and drying time were examined. The following results were obtained. 1. High compressive strength was maintained in the condition of 70 degrees C of heating temperature, with more than 15 minutes of heating time and more than 15 minutes of drying time. In this condition up to 90 minutes could be saved in comparison with the conventional method. 2. Plaster models had a tendency to shrink in the condition of 70 degrees C of heating temperature.

Calcium Sulfate↗
PubMed1989

Characterization of very low density lipoprotein from Watanabe heritable hyperlipidemic rabbits.

We investigated the properties of very low density lipoprotein (VLDL) from two types of Watanabe heritable hyperlipidemic (WHHL) rabbits: one with a high incidence of coronary atherosclerosis (type 1), and the other with a low incidence (type 2). When incubated with mouse peritoneal macrophages, VLDL from type 1 WHHL rabbit (type 1-VLDL) stimulated cholesteryl ester synthesis 10.5-fold more than VLDL from the type 2 WHHL rabbit (type 2-VLDL) did. Moreover, a similar difference was seen in the stimulation of cholesteryl ester synthesis in peritoneal macrophages isolated from the WHHL rabbits. The mass ratios of cholesterol to protein in type 1- and type 2-VLDL were 5.69 and 2.05, respectively. Agarose gel electrophoresis of type 1-VLDL showed beta mobility, and that of type 2-VLDL showed pre-beta mobility. No difference was seen between the sizes of VLDL particles of the two types. The amount of apolipoprotein E in type 1-VLDL was greater than that in type 2-VLDL. In conclusion, the difference between type 1 and type 2 WHHL rabbits is at least partly due to the presence in type 1 animals of VLDL particles rich in cholesteryl esters and apolipoprotein E, particles which are very similar to beta-VLDL in conformation.

Animals↗
PubMed1988

Uptake of acetylated LDL by peritoneal macrophages obtained from normal and Watanabe heritable hyperlipidemic rabbits, an animal model for familial hypercholesterolemia.

Acetylated low-density lipoprotein (acetyl-LDL) stimulated the incorporation of [14C]oleate into cholesteryl [14C]oleate in peritoneal macrophages from both normal and Watanabe heritable hyperlipidemic (WHHL) rabbits. A degradation study showed that macrophages from WHHL rabbits degraded the same amount of 125I-labeled acetyl-LDL as macrophages from normal rabbits. These findings indicate that macrophages of WHHL rabbits have functional acetyl-LDL receptors.

Animals↗
PubMed1988

Prevention of atherosclerotic progression in Watanabe rabbits by probucol.

The foam cell has been recognized as a characteristic feature of xanthomas in skin and tendons, and also of atheromas. Many foam cells in these lesions share properties characteristic of the macrophages. Therefore macrophages may be the progenitor of certain foam cells that are involved in atherogenesis. Several investigators demonstrated in vitro that macrophages can ingest large amounts of certain chemically modified lipoproteins, such as acetylated low-density lipoprotein (LDL) and malondialdehyde-treated LDL, through the process of receptor-mediated endocytosis. By this process, macrophages become foam cells. But this process has not been demonstrated in vivo. Recently, oxidized LDL has been suggested to play an important role in atherogenesis by facilitating the accumulation of lipids in macrophages in vitro. Probucol, originally developed as an antioxidant, prevents this oxidative modification of LDL in vitro. Moreover, there are some clinical reports that probucol induces regression of cutaneous and tendon xanthomas in patients with homozygous familial hypercholesterolemia. A question was posed whether in vivo probucol could prevent the progression of atherosclerosis in homozygous Watanabe heritable hyperlipidemic (WHHL) rabbits, an animal model for familial hypercholesterolemia. At age 2 months, 8 WHHL rabbits were classified into 2 groups: group A rabbits were controls and group B rabbits were treated with 1% probucol. After 6 months of treatment, average plasma concentrations of cholesterol were 704 +/- 121 mg/dl in group A and 584 +/- 61 mg/dl in group B. The percentage of surface area of total thoracic aorta with visible plaques in group A vs group B was 54.2 +/- 18.8% vs 7.0 +/- 6.3%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Scanning electron microscopic study of denervated and reinnervated neuromuscular junction.

Morphological changes of the subneural apparatus (SNA) during denervation and reinnervation are demonstrated using the hamster peroneus longus muscle. One week after nerve section, synaptic grooves (SGs) were more shallow, with lowered sarcoplasmic ridges. After 4 weeks, the whole SNA area was elevated above the sarcolemma as a flat plate, which persisted as a fusiform bulge for more than 8 weeks. There was a rapid and progressive decrease in the number of junctional folds (JFs) and slit-to-pit transformation of their openings. There was no trace of the SNA after 16 weeks. By 4 weeks after nerve suture, SGs were flattened but did not form the plate-like elevation. Many shallow pit-like JFs still persisted. At 10 weeks, deep SGs started to be restored with an increased number of deep slit-like JFs. The SNA recovered its normal structural organization by the week 20. However, a few pit-like vestigial JFs were present outside the groove.

Animals↗
PubMed1988

Novel densitometric method for endonuclease analysis of Escherichia coli DNA samples containing multiple plasmids.

We developed a novel method whereby the digestion pattern of each plasmid was distinguished in a sample of endonuclease-digested plasmid DNAs which contained multiple plasmids extracted from a bacterial strain. This method consisted of two procedures. (i) The concentration ratio of each undigested plasmid DNA and of each digested DNA fragment was calculated on the basis of densitometric scanning of an electrophoretogram, and the concentration ratio was then compared with the theoretical concentration ratio to determine from which plasmid each fragment was generated. (ii) The second procedure involved rapid visual identification with a scanning graph. We thus analyzed five strains of Escherichia coli that harbored several cryptic plasmids. The two procedures made it possible to analyze the restriction digestion pattern of each plasmid without the need to isolate the individual plasmids, except in the case of certain fragments. Even when the digested patterns of these exceptional fragments could not be distinguished completely, however, our method had the advantage that peak patterns of plasmids could be compared visually among different bacterial strains.

DNA Restriction Enzymes↗
PubMed1988

Distribution and progression of coronary arterial and aortic lesions in the conventional Watanabe heritable hyperlipidemic rabbit--quantitative analysis.

The distribution and progression of coronary arterial and aortic lesions were examined in 40 conventional Watanabe heritable hyperlipidemic (WHHL) rabbits. They were classified according to age into stage I (3-5 months old, 14 rabbits), stage II (6-12 months old; 12 rabbits) and stage III (14-28 months old; 14 rabbits). Fifteen normal Japanese rabbits served as controls. The findings obtained from serial and transverse sections of each of the extramural coronary arteries (ECA) and transverse sections of 4 to 5 equal pieces of whole ventricle for intramural coronary arteries (ICA) were quantified by an image analyzer. Atherosclerosis with positive Sudan III stain was seen in aorta, ECA and ICA over 200 mu in diameter. Atherosclerotic lesions were noted in the aortic arch in stage I rabbits and in the whole aorta in stages II and III rabbits. In ECA, stenosis due to atherosclerosis was noted in 14, 33 and 93% of stages I, II and III rabbits, respectively. Stenosis of over 75% in the orifices of the left and right coronary arteries was noted frequently (71%), while mural thrombi, hemorrhage, intimal rupture and recanalization were seen rarely. Striking features were non-atherosclerotic stenosis with negative Sudan III, seen in the ICA less than 200 mu in diameter of almost all the hearts of stages II and III rabbits. Acute and old myocardial infarction appeared in 5 of the 14 hearts of the stage III rabbits and the infarct-related ECA showed severe stenosis of over 90%. In conclusion, to detect coronary atherosclerosis, serial and transverse sections of ECA are needed. In conventional WHHL rabbits, the incidence of stenosis in ECA is very high, compared with that of the previous reports, and myocardial infarction is due to severe stenosis in ECA. Non-atherosclerotic lesions in ICA occur before the appearance of the atherosclerotic lesions in ECA.

Animals↗
PubMed1988

The concentration of serum lipids in Zen monks and control males in Japan.

The concentrations of total, low density lipoprotein (LDL), and high density lipoprotein (HDL) cholesterol, triglyceride and apoprotein B have been examined in Zen monks whose intake of animal products was almost negligible for 2 to 8 years, and in age-matched (24 to 35 years) control Japanese males who eat Western style food. The mean levels of total, LDL- and HDL-cholesterol, and apoprotein B were 135.1 +/- 16.7, 73.0 +/- 11.6, 50.4 +/- 9.6, and 70.6 +/- 15.6 mg/dl, respectively in Zen monks. These levels were 28.5, 32.8, 18.8, and 23.9% lower in Zen monks than in control Japanese males. These values are statistically significant compared to those of the controls (p less than 0.01). There were no significant changes in the level of triglyceride in both groups.

Adult↗
PubMed1988

[Left ventricular wall thickness in hypertrophic cardiomyopathy: comparisons of measurements by magnetic resonance imaging, cineangiography, and echocardiography].

To evaluate the usefulness of magnetic resonance imaging (MRI) in measuring regional wall thickness of the left ventricle, 11 patients with hypertrophic cardiomyopathy (HCM) were imaged. The measurements were compared with those obtained by two-dimensional echocardiography (2D-echo) and cineangiography. Regional wall thickness was ascertained at six locations including the base, middle, and apex of the interventricular septum (IVS) and left ventricular posterior wall (LVPW) from the two selected transverse sections. All of these six locations were also measured for the IVS by biventriculography and for the LVPW by left ventriculography with the left anterior oblique view. Only the base was measured for both the IVS and LVPW using 2D-echo because of the difficulty in obtaining good images for the middle and apex of the left ventricle. The measurements by MRI correlated well with those obtained by 2D-echo and cineangiography in the majority of locations. At the base, where the wall thickness was measured by the three methods, the measurements of the IVS correlated well each other (r = 0.63 to 0.81). However, a good correlation was obtained only between 2D-echo and MRI for the LVPW r = 0.75. The correlation between MRI and cineangiography was generally good for the IVS at any levels (r = 0.76 to 0.87), but not for the LVPW. This was partially due to the narrow range of data for the LVPW as well as to the difficulty in determining the epicardial border in left ventriculograms. In conclusion, regional wall thickness can be correctly measured by MRI in any locations of the left ventricle even at the apex, where measurement is difficult by other methods.

Adolescent↗
PubMed1988

[Measurement of cerebral blood volume by reflections spectrophotometry: methodological improvement and quantitative evaluation].

The authors described methodological improvement and quantitative evaluation in measurement of cerebral blood volume (CBV) by reflectance spectrophotometry. The measurement of blood volume by this method has not been applied to the brain tissue because of the methodological difficulties. In order to obtain the accurate CBV values with this method, it is necessary to keep the proper contact between the sensor for the measurement and the brain tissue to be measured. For this purpose we developed a balance arm. A sensor for CBV measurement was fixed with the one side of the arm and a weight was installed to the other side. The pressure of the sensor to the brain can be adjusted by moving the weight, and the sensor was placed on the brain tissue with the proper pressure. Moreover, the sensor was attached with an acryl-made cap to make the pressure adjustment easier by enlarging the contact surface and to enable to observe the vasculature on the surface of the brain. With this improved method the reasonable changes of CBV could be obtained when the CO2 gas was inhalated and cerebral ischemia was produced in cats. The possibility of the quantitative evaluation was investigated using the homogenized brain tissue of cats. After the elimination of the blood from the brain by the perfusion with the saline, the brain was removed and homogenized. Then, the definite volume of blood, of which hemoglobin volume was already known, was added and measured by this method.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

The effectiveness of ethanol gauze for hand disinfection in surgical wards.

The effectiveness of ethanol gauze in removing transient bacteria on the hands was investigated in a surgical ward during clinical nursing rounds. Two nurses with similar duties were selected as subjects for each round; one disinfected her hands with ethanol gauze when moving between patients while the other immersed her hands in 0.05% aqueous chlorhexidine gluconate when aware of contaminating her hands. Hand samples were taken after preliminary disinfection before the round, and again after the round on 37 occasions. Pseudomonas aeruginosa and Staphylococcus aureus were not detected in nurses using ethanol gauze, except in one nurse where S. aureus was isolated from both the pre- and postround hand culture. Both organisms were detected on four occasions from the postround hand cultures in the chlorhexidine group. Acinetobacter anitratus was not removed by pre-round disinfection, and was found on five and 11 occasions from the postround hand cultures in the ethanol gauze and chlorhexidine groups, respectively.

Bacteria↗
PubMed1987

Probucol prevents the progression of atherosclerosis in Watanabe heritable hyperlipidemic rabbit, an animal model for familial hypercholesterolemia.

In this study, we questioned whether in vivo probucol could prevent the progression of atherosclerosis in homozygous Watanabe heritable hyperlipidemic (WHHL) rabbits, an animal model for familial hypercholesterolemia. At 2 months of age, eight WHHL rabbits were divided into two groups. Group A (n = 4) was fed standard rabbit chow for 6 months. Group B (n = 4) was fed standard rabbit chow containing 1% probucol for 6 months. At the end of the experiments, average plasma concentrations of cholesterol were 704 +/- 121 mg/dl in group A and 584 +/- 61 mg/dl in group B, respectively. The percentage of surface area of total thoracic aorta with visible plaques in group A versus group B was 54.2% +/- 18.8% versus 7.0% +/- 6.3%, respectively. What was noteworthy was that the percentage of plaque in the descending thoracic aorta was almost negligible (0.2% +/- 0.2%) in group B rabbits compared to that in group A rabbits (41.1% +/- 20.2%). Low density lipoproteins (LDL) isolated from WHHL rabbits under treatment with probucol (group B) were shown to be highly resistant to oxidative modification by cupric ion and to be minimally recognized by macrophages. On the contrary, LDL from group A rabbits incubated with cupric ion showed a 7.4-fold increase in peroxides (thiobarbituric acid-reactive substances) and a 4.3-fold increase in the synthesis of cholesteryl ester in macrophages compared to those of LDL from group B rabbits. Thus, probucol could definitely prevent the progression of atherosclerosis in homozygous WHHL rabbits in vivo by limiting oxidative LDL modification and foam cell transformation of macrophages.

Animals↗