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Biomedical subjects

Y Sakabe

Publications and source records attributed to Y Sakabe.

At least 19 recordsLinked to original sources
PubMed2002

Tumour necrosis factor-alpha receptors are present in the corpus luteum throughout the oestrous cycle and during the early gestation period in pigs.

To determine the physiological significance of tumour necrosis factor-alpha (TNFalpha) in the regulation of luteal functions in pig, this study was conducted to identify the presence of functional TNFalpha receptors in porcine corpora lutea (CL) throughout the oestrous cycle and the early gestation. The CL were isolated from pigs on days 4, 6, 8, 12 or 15 of the oestrous cycle (n=3; day 0 = oestrus) and days 15, 20 or 25 of gestation (n=3; day 0 = mating). A Scatchard analysis revealed the presence of a high-affinity binding site for TNFalpha in all samples (dissociation constant; 2.7 +/- 0.51 to 5.8 +/- 0.50 nM). The concentration of TNFalpha receptors was higher on day 15 of the oestrous cycle than on days 4 and 8 of the oestrous cycle (p < 0.05). Furthermore, TNFalpha receptor concentrations in the CL on days 15, 20 and 25 of gestation were significantly lower than on day 15 of the oestrous cycle (p < 0.05). On day 9 of the oestrous cycle, exposure of cultured luteal cells to 0.06-60 nM TNFalpha stimulated prostaglandin (PG) F2alpha and PGE2 secretion in a dose-dependent manner (p < 0.05). These results indicate that functional TNFalpha receptors are present in the porcine CL throughout the oestrous cycle and early gestation, and suggest that TNFalpha plays one or more physiological roles in regulating CL function throughout the oestrous cycle and the early gestation period. In addition, TNFalpha receptor concentration in the CL of the late luteal stage (day 15) of the oestrous cycle was higher than on the respective day in the early pregnant pig, suggesting that TNFalpha plays a role in accomplishing luteolysis in the porcine CL.

Animals↗
PubMed1999

Luteinizing hormone receptors in the bovine corpus luteum during the oestrous cycle and pregnancy.

The concentration and affinity of luteinizing hormone (LH) receptors in bovine luteal tissues during the oestrous cycle and pregnancy were investigated by Scatchard analysis of the binding of 125I-labeled human chorionic gonadotropin. Corpora lutea (CL) were classified into five stages of the oestrous cycle and three stages of pregnancy. The concentration of LH receptors sharply increased from the early I stage of the oestrous cycle (Days 2-3; 3.09 fmol mg(-1) protein) to the early II stage (Days 5-6; 9.44 fmol mg(-1) protein) and then remained constant until the late luteal stage (Days 15-17; 8.14-9.56 fmol mg(-1) protein). The LH receptors could not be analysed in the regressed luteal tissue due to the small amounts of binding. There was no significant difference in the concentrations of LH receptors (5.63-9.64 fmol mg(-1) protein) among the three stages of pregnancy. Moreover, the concentrations of the receptors in the CL of pregnancy were comparable to those in the mid-cycle CL. The binding affinity did not change significantly during the oestrous cycle and pregnancy. Based on these results, it is assumed that the luteal function during the entire period of pregnancy might be regulated, at least in part, by LH, which is mediated via its specific receptors, and that the luteal function during pregnancy seems not to be regulated by changes in the binding capacity and affinity of LH receptors. To understand the physiological roles of LH in regulating luteal function in pregnant cows, further studies are required.

Animals↗
PubMed1992

Collaborative study using the preincubation Salmonella typhimurium mutation assay for airborne particulate matter in Japan. A trial to minimize interlaboratory variation.

A collaborative study has been performed over a period of 3 years to develop a suitable method for monitoring the mutagenicity of airborne particulate matter. The study was organized with 8 laboratories and performed in the following steps: (1) selection of a suitable technique for each process involved in the mutagenicity monitoring, (2) developing a tentative protocol by combining systematically the selected techniques, (3) evaluation of the protocol by intra- and inter-laboratory studies, (4) modification of the protocol according to the evaluation, and (5) evaluation of the modified protocol by conducting an interlaboratory study. We found a suitable method for mutagenicity monitoring of particles in the atmosphere. Airborne particles were sampled with a high-volume sampler, the samples were stored at -80 degrees C, extracted by sonication using dichloromethane, solvent-exchanged, and assayed by the preincubation method using Salmonella typhimurium TA98 and TA100. The observed mutagenic activity was normalized with that of an internal standard. Round robin tests revealed that the method resulted in excellent reproducibility. The coefficient of variation for mutagenic activities of airborne particulate samples collected in various districts of Japan were in the range of 14.7 +/- 6.6% to 19.6 +/- 4.0% for strains TA98 and TA100 with and without metabolic activation. We also found that the plate incorporation method was equivalent to the preincubation method for airborne particulate extracts.

Air Pollutants↗
PubMed1990

Occurrence of 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), 2-amino-6-methyldipyrido[1,2-a:3',2'-d]imidazole (Glu-P-1) and other heterocyclic amine mutagens in oil of charred egg yolk (ranyu).

Mutagenicity of oil of charred egg yolk (called ranyu in Japanese), which is commercially available and consumed as a health food in Japan, was tested on Salmonella typhimurium strains TA98 and TA100 with and without metabolic activation. Both strains showed a high response to the oil, and the number of His+ revertant colonies with strain TA98 was 15,000-20,000 for 1 g equivalent amount of oil. The mutagens were purified by acid extraction, chloroform extraction after alkalization, dialysis, adsorption to blue cotton, passing through a Sephadex LH-20 column and several stages of high-pressure liquid chromatography with reverse-phase columns. At least 7 heterocyclic amine mutagens were detected. Two of them were suggested to be 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) and 2-amino-6-methyldipyrido [1,2-a:3',2'-d]imidazole (Glu-P-1). One was suggested to be 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ). The others were not identified but distinguishable from 12 known heterocyclic amine mutagens. The estimated minimum contents of IQ and Glu-P-1 were 1.1 ng/g and 4.8 ng/g, respectively.

Chromatography, High Pressure Liquid↗
PubMed1990

Evaluation of cardiac tissue from two-dimensional echocardiogram: analysis of gray level and its distribution.

Two-dimensional echocardiograms of parasternal long-axis view were recorded and the mean echo intensity and its distribution in the interventricular septum were examined for the purpose of inferring myocardial tissue. Six healthy subjects (N), 29 with left ventricular hypertrophy (LVH), and 12 with old anteroseptal myocardial infarctions (MI) were used in the study. Settings for gain control were adjusted in the constant manner. Data were recorded on a Video tape recorder, with analog data converted to digital signals, subjected to a low-pass filtering, and then analyzed by a Computer tomography image processor. The region of interest was set within the interventricular septum, and a mean relative echo intensity and its histogram (number of pixels showing different echo intensity) was evaluated. The histogram patterns were examined and the parameter for skewness, which shows asymmetrical characteristics, and the parameter for kurtosis, which shows degree of peakedness of distribution, were calculated. Relative echo intensity was found to increase in the order MI greater than LVH greater than N. Histograms showed the majority of pixels were concentrated at the low echo intensity level in the normal group, while pixels were distributed in a relatively gentle slope around the mean value in the LVH group. Many pixels were in the high intensity levels in the MI group, although the rest were dispersed throughout various intensities including low level. The differences are thought to be related to the extent and density of fibrosis. Analysis of two-dimensional echocardiographic echo intensity and distribution may be useful in characterizing myocardial tissues.

Adult↗
PubMed1988

[Analysis of myocardial texture in two-dimensional echocardiographic images].

To evaluate tissue changes, we studied myocardial texture using two-dimensional echocardiographic images. We investigated 19 normal subjects, 28 patients with left ventricular hypertrophy, and 12 patients with old anteroseptal myocardial infarction of longer than one year duration. Using 2.5, 3.5, and 5.0 MHz transducers, two-dimensional echocardiograms in the parasternal long-axis view were obtained, and the textures of the interventricular septal images were classified in three types; type I, with a nearly uniformly speckled or echolucent appearances; type II, with multiple, discrete, small (2 to 4 mm) highly refractile echoes; type III, with larger highly refractile echoes (greater than 4 mm) appearing as a cluster of broad patches or band-like echoes. Normal subjects belonged to the type I texture, while many with left ventricular hypertrophy belonged to the type II category. Type III was often observed in patients with old anteroseptal infarction. Using a transducer of higher frequency, there tended to be a shift from type II to I or type III to II. In phantom experiments using carbolandam granules instead of the myocardium, the echocardiographic texture became rough when the phantom was farther from the transducer or the transducer was of low frequency. We suggest that the texture in two-dimensional images may reflect myocardial tissue changes, when other factors including the apparatus and technique remain stable.

Adult↗
PubMed1987

Effect of roasting on ochratoxin A level in green coffee beans inoculated with Aspergillus ochraceus.

The heat stability of ochratoxin A in green coffee beans inoculated with Aspergillus ochraceus was studied. Heat treatment (roasting) at 200 degrees C for 10 or 20 min reduced the levels of ochratoxin A by only 0-12% in the dried whole beans. Almost all of the ochratoxin A was infused into the coffee decoction when the roasted samples were ground and extracted with boiling water. Therefore, the reduction of ochratoxin A concentration of contaminated coffee beans by roasting under these conditions is ineffective.

Aspergillus↗
PubMed1987

[Two-dimensional echocardiographic echo intensity distribution by histographic analysis].

To assess myocardial tissue changes, the distribution of echo intensities of two-dimensional echocardiograms was analyzed using a histogram. The materials were obtained from six normal subjects (N), 29 patients with left ventricular hypertrophy (LVH), and 12 patients one year or more after the onset of anteroseptal myocardial infarction (MI). A transducer with a central frequency of 2.3 MHz was used. Scanner receiver settings, including sensitivity-time control, were kept constant for all subjects. The parasternal long-axis image was digitized and computer-processed. The region of interest was located within the interventricular septum. The mean echo intensity and its distribution were studied. The shape of the histogram was evaluated for skewness and kurtosis. Relative echo intensity: N = 0.23 +/- 0.07 (mean +/- SD) less than LVH = 0.58 +/- 0.18 less than MI = 1.07 +/- 0.25 (p less than 0.01). Skewness: N = 1.58 +/- 0.63 greater than LVH = 0.60 +/- 0.61 greater than MI = -0.14 +/- 0.43 (p less than 0.01). Kurtosis: N = 18.0 +/- 7.3 greater than LVH = 10.5 +/- 3.3 greater than MI = 7.7 +/- 0.9 (p less than 0.01). These differences may closely relate to an increase in collagen fiber content. Consequently, analysis of the myocardial echo intensity distribution, in addition to mean echo intensities, may become a clinically useful approach for identifying myocardial tissue changes.

Adult↗
PubMed1987

[Ultrasonic tissue characterization in diagnosing myocardial infarction].

To evaluate myocardial tissue changes using two-dimensional (2D) echocardiography, several approaches were attempted. 1. Quantitative evaluation of the myocardial echo intensity by computerized image processing in patients with old anteroseptal myocardial infarction: 2D echocardiograms of the parasternal long-axis view were converted to digital images to measure the echo intensity of the regions of interest (ROI) placed in the interventricular septum (IVS), the left ventricular posterior wall (LVPW), the left ventricular cavity, and the pericardium. The mean value of the echo intensity was compared with that of the pericardium (maximum echo intensity) and of the left ventricular cavity as the minimum. In 12 normal subjects, the relative echo intensity of the IVS was 0.40 +/- 0.05 (mean +/- SE), whereas it was 0.71 +/- 0.06 in 11 patients with old MI (p less than 0.001). Color display facilitated the visual recognition of the numerical differences in echo intensities. 2. Evaluation of the myocardial echo intensity in acute phase of myocardial infarction: In nine normal elderly persons, the relative echo intensity of IVS was 0.29 +/- 0.14, and there was no significant change in the early stage (three to seven days) of acute infarction (0.31 +/- 0.14). Two weeks later, however, a significant increase was noted (0.61 +/- 0.10) (p less than 0.01), probably due to an increase in collagen fibers. 3. Changes of the myocardial echo intensity in acute myocardial ischemia: Two-dimensional echocardiograms were recorded in nine open-chest dogs using 3 and 5 MHz transducers before and 10 min, 1 hr, 3 hrs, and 6 hrs after coronary artery ligation. With the 5 MHz transducer, the echo intensity of the ischemic myocardium was decreased after 10 min and was remarkable after 1 hr (0.24 +/- 0.08), and restored in six hrs. These changes could not be detected using the 3 MHz transducer. 4. An in vitro study for assessment of ultrasonic attenuation in the canine infarcted myocardium: The frequency dependency of ultrasonic attenuation of the resected canine myocardium in the frequency region of 2 MHz to 7 MHz was estimated one and two weeks after coronary artery ligation. The distributions of attenuation characteristics were nearly consistent with those of collagen contents determined histologically. In conclusion, we demonstrated that acute and chronic ischemia of the myocardium influences the transmission and reflection of ultrasound. By applying this property, ultrasonic tissue characterization may become a useful tool for detecting myocardial ischemia in the near future.

Adult↗
PubMed1985

Studies on residual antibacterials in foods. IV. Simultaneous determination of penicillin G, penicillin V and ampicillin in milk by high-performance liquid chromatography.

A rapid and simple method for the simultaneous determination of penicillin G (PCG), penicillin V (PCV) and ampicillin (ABPC) in milk is described. The retention behaviour of these beta-lactam antibiotics in reversed-phase liquid chromatography with mobile phases containing sodium alkylsulphonate was studied. Good separations were obtained with methanol-water-0.2 M phosphate buffer (pH 4.0) (5:13:2) containing 11 mM sodium 1-heptanesulphonate and a LiChrosorb RP-18 column. The sample was pre-treated with a Sep-Pak C18 cartridge. The peaks corresponding to each beta-lactam antibiotics can be confirmed with the treatment using penicillinase. The recoveries from milk fortified with sodium PCG, potassium PCV and ABCP at levels of 0.5 and 0.1 micrograms/g each were generally better than 87% and the relative standard deviations were 1.17-4.98%. The detection limits corresponded to 0.03 microgram/g of these beta-lactam antibiotics in milk.

Ampicillin↗
PubMed1985

Studies on the analysis of food additives by high-performance liquid chromatography. V. Simultaneous determination of preservatives and saccharin in foods by ion-pair chromatography.

A high-performance liquid chromatographic method for the simultaneous determination of sorbic acid, benzoic acid, p-hydroxybenzoic acid and its methyl, ethyl, isopropyl, n-propyl, isobutyl, n-butyl esters and saccharin in foodstuffs is described. For good separations of these compounds, acetonitrile-water-0.2 M phosphate buffer pH 3.6 (7:12:1) containing 2 mM cetyltrimethylammonium bromide as an ion-pair reagent and a Nucleosil 5C18 column are required. A steam distillation method and a Sep-Pak C18 cartridge method for the sample preparation are compared. The recoveries from a coffee drink were generally better than 93.8% and the relative standard deviations were 0.85-2.15% for the Sep-Pak C18 cartridge method.

Beverages↗
PubMed1985

Studies on residual antibacterials in foods. III. High-performance liquid chromatographic determination of penicillin G in animal tissues using an on-line pre-column concentration and purification system.

A simple and reproducible method for the determination of residual penicillin G in edible animal tissues by high-performance liquid chromatography (HPLC) is described. The method consists in an off-line clean-up step using a basic aluminium oxide column and a Sep-Pak C18 cartridge and an on-line pre-column concentration and purification system. The procedure shows good sensitivity and precision. The recoveries from cattle liver, kidney and muscle fortified with 1 microgram/g of sodium penicillin G were 75.0-92.6% and the relative standard deviations were 2.35-4.06%. The detection limit corresponded to 0.05 micrograms/g of sodium penicillin G in animal tissues.

Animals↗
PubMed1985

Caffeine degradation and increased ochratoxin A production by toxigenic strains of Aspergillus ochraceus isolated from green coffee beans.

The growth and ochratoxin A production of Aspergillus ochraceus strains S-235-100 and IFM 0458, which were isolated from green coffee beans and glutinous rice, respectively, were examined in yeast extract-sucrose (YES) medium containing 0.1 to 1.0% caffeine. The mycelial growth and ochratoxin A formation of strain IFM 0458 was inhibited by caffeine at concentrations over 0.1%, and ochratoxin A was not produced at caffeine levels of 0.5% and 1.0%. Contrary to this, A. ochraceus strain S-235-100 produced a larger amount of ochratoxin A in the presence of 0.5% and 1.0% caffeine when grown on YES medium, reaching a maximum after 15 to 20 days of incubation. The formation of ochratoxin A by nine additional strains of A. ochraceus, three strains of A. elegans and one strain of A. sclerotiorum isolated from green coffee beans was determined on rice and ground green coffee media. A significant degree of degradation of caffeine in the green coffee medium was demonstrated with cultures of nine A. ochraceus isolates from green coffee beans. Most of these isolates showed the potential to grow on moist green coffee beans and to produce a significant amount of ochratoxins.

Aspergillus↗
PubMed1985

[Quantitative evaluation and color display of echo intensity by two-dimensional echocardiography].

To assess myocardial tissue changes by two-dimensional echocardiography, quantitative evaluation and color display of the echo intensity were attempted using computerized image processing. The materials consisted of 11 patients with old anteroseptal myocardial infarction one year or more after the onset (OMI), and 12 normal subjects. Two-dimensional echocardiograms in the parasternal long-axis view were obtained using a commercially-available phased-array sector scanner. Scanner receiver settings including sensitivity-time control were maintained constant in all subjects. Images were recorded on the U-matic tape using a video tape recorder, then stop-frame end-diastolic images were converted to digital images. To measure echo intensity, regions of interest (ROI) were placed in the interventricular septum (IVS), the left ventricular posterior wall (LVPW), the left ventricular cavity, and the pericardium. The mean value of the echo intensities was determined for each ROI. Then, the relative echo intensity of the IVS or LVPW was calculated using the mean value of the pericardium as the maximum echo intensity, and the mean value of the left ventricular cavity as the minimum echo intensity. In normal subjects, the relative echo intensity of the IVS was 0.40 +/- 0.05 (mean +/- SE) and that of the LVPW was 0.31 +/- 0.02. By contrast, in patients with OMI, there was a significant increase (p less than 0.001) in the relative echo intensity of the IVS (0.71 +/- 0.06). The relative echo intensity of the LVPW was less than normal, but the difference was not statistically significant.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

Measurement of lung density in congestive heart failure by computed tomography.

The computed tomography (CT) number within the region of interest (ROI) was used as a parameter to assess lung density in patients with congestive heart failure. Thirty-eight patients with valvular heart disease (VHD) and 34 patients with ischemic heart disease (IHD) were studied. Based on the New York Heart Association (NYHA) classification, 24 VHD patients were in class I or II (VHD I-II) and the other 14 were in NYHA class III or IV (VHD III-IV). Eighteen patients with IHD were in NYHA class I or II (IHD I-II) and 16 were in class III or IV (IHD III-IV). The CT number was measured bilaterally at the upper, middle and lower levels of the chest and compared with the corresponding values in 21 normal subjects (Group N). In a preliminary study on Group N, the CT numbers were insensitive to the size of the ROI, but were closely related to its location. In clinical applications, the mean values of the CT numbers in all six lung fields increased in the order of IHD I-II, to VHD I-II, IHD III-IV and VHD III-IV. Except for patients in IHD I-II, they were significantly larger than in Group N. The relationship between the CT number and the systolic and mean pulmonary arterial pressures and the pulmonary capillary wedge pressure were evaluated in 36 patients. Significant correlations were obtained in all six lung fields (r = 0.65-0.78, p less than 0.001). The results suggest that measurement of lung density by CT is useful for the quantitative evaluation of the severity of disease in patients with congestive heart failure.

Adult↗
PubMed1984

[Estimation of the infarct size by two-dimensional echocardiography in cases with acute myocardial infarction].

We evaluated clinically the infarct size in addition to left ventricular end-diastolic and end-systolic volumes (EDV, ESV) and ejection fraction (EF) using two-dimensional echocardiography (2-D) and algorithms based on the modified Simpson's rule. EDV, ESV and EF obtained by 2-D and three algorithms were compared with those obtained by left ventriculography in 23 patients with various heart diseases. Correlation coefficients obtained by our and other two algorithms were 0.88, 0.88 and 0.90, respectively, for EDV and ESV (p less than 0.01), and 0.71, 0.60 and 0.84 for EF (p less than 0.01). Myocardial mass of the region showing asynergy (asynergic size) was calculated by the above-mentioned three methods and compared with peak serum CK values in 14 patients with acute myocardial infarction. The correlation coefficient between both values was 0.76 (p less than 0.01) by our algorithm and it was higher than by other two algorithms (0.37 and 0.70). The time course of changes in asynergic size in acute myocardial infarction was studied by the use of 2-D and our algorithm. Asynergic size was significantly larger on the day of the onset (24.9 +/- 2.9 ml, mean +/- SE) than the third (21.5 +/- 2.7 ml) and seventh day (20.7 +/- 3.0 ml) after the onset (p less than 0.01). These results suggest that one can make a quantitative and serial estimation of infarct size as well as left ventricular volume by 2-D and our modified model, and that our algorithm is suitable for the purpose.

Cardiac Volume↗