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Biomedical subjects

A Nozaki

Publications and source records attributed to A Nozaki.

At least 19 recordsLinked to original sources
PubMed1998

Energy dispersive X-ray fluorescence spectrometry of major tissues of silky fowls.

This report is to survey elements in frozen or freeze-dried samples of major organs of silky fowls with energy dispersive X-ray fluorescence spectrometer (EDXRF). There was not essential difference between frozen and freeze-dried samples. Of major elements, P. S, K, and Cl were always detected and Mn, Fe, Ca, and Zn were detectable in certain organs. Iodine was detected in thyroid glands. Occasionally Br was detected. The duration of freeze drying, 24 hr or 7 days, did not make significant difference in elemental analysis.

Animals↗
PubMed1998

The surface color measurement of major tissues of silky fowls and White Leghorns.

This report concerns the surface color of major organs of the silky fowl and White Leghorn chicken as measured by a color analyser. Although it is obvious that organs of the silky fowl look darker than those of the white leghorn, the color measurement of these organs has not yet been reported. The authors found that color differences between silky fowls and White Leghorns were significant in lung, brain, skin, and gluteal muscle. But the surface color of kidney and cardiac muscle of the two groups of fowl was not significantly different. The present data were represented in color charts.

Animals↗
PubMed1998

Technique for arterial-phase contrast-enhanced three-dimensional MR angiography of the carotid and vertebral arteries.

Our goal was to evaluate whether contrast-enhanced three-dimensional MR angiography using the MR Smartprep technique would enable us to obtain arterial-phase MR angiograms of the carotid and vertebral arteries. The study included 35 patients with suspected lesions of the neck in whom the MR Smartprep technique was used for MR angiography performed with a 1.5-T superconducting system. The tracker volume was placed primarily in the middle part of the right common carotid artery. The imaging volume was placed in a coronal direction to include the carotid and vertebral arteries from the aortic arch to the skull base. A centric phase-ordering scheme was used. Imaging times were 20 to 38 seconds for 14 patients and 11 to 16 seconds for 21 patients. By using a smaller tracker volume and an imaging time of less than 16 seconds, we were able to achieve a 100% successful triggering rate and to delineate selectively arterial-phase carotid and vertebral arteries with almost no venous contamination. Contract-enhanced 3-D MR angiography with the MR Smartprep technique was useful for showing arterial-phase carotid and vertebral arteries selectively.

Aorta, Thoracic↗
PubMed1997

Diffusion-weighted imaging of the human optic nerve: a new approach to evaluate optic neuritis in multiple sclerosis.

The apparent diffusion coefficient (ADC) in the optic nerve was measured from diffusion-weighted magnetic resonance imaging using an intravoxel incoherent motion (IVIM) sequence. The subjects were seven normal volunteers and eight patients with multiple sclerosis (MS) with a total of four optic nerves with acute neuritis and nine nerves with chronic neuritis. The mean ADC (4.18 +/- 1.13 x 10(-3) mm2/s, n = 9) in the optic nerves with chronic neuritis was significantly higher than that in normal volunteers (1.56 +/- 0.675 x 10(-3) mm2/s, n = 14) and that in the nerves with acute neuritis (0.94 +/- 0.43 x 10(-3) mm2/s n = 4) (P < 0.001). The ADC is useful in assessing MS foci in the optic nerves.

Adolescent↗
PubMed1997

MR angiography of the renal artery: comparison of breath-hold two-dimensional phase-contrast cine technique with the phased-array coil and breath-hold two-dimensional time-of-flight technique with the body coil.

Breath-hold 2D phase-contrast (PC) cine MR angiography with a phased-array coil and 2D time-of-flight (TOF) MR angiography were performed in the renal arteries and their findings were compared. Breath-hold 2D thin slice PC and TOF MR angiography were performed in 10 normal volunteers for renal arteries. A PC technique with k-space segmentation was utilized with the phased-array coil. A PC technique provided visualization of the renal artery more distally than a TOF technique (4.8 +/- 0.5 cm vs. 3.7 +/- 0.8 cm). With cardiac triggering, distal renal arteries were well demonstrated in PC MR angiography. On PC images, up- or downward movements of the mid to distal renal arteries with aortic pulsatility were recognized. The quality of the images was better with the PC than with the TOF technique (3.4 vs. 2.7). The mid to distal portions of the renal arteries translationally move with aortic pulsatility. To consistently visualize and evaluate them on MR angiography, cardiac triggering might be required to reduce the effects of pulsatile motions of the renal artery in the use of a phased-array coil.

Adult↗
PubMed1997

Nitrogen dioxide in indoor ice skating facilities: an international survey.

An international survey of nitrogen dioxide (NO2) levels inside indoor ice skating facilities was conducted. One-week average NO2 concentrations were measured inside and outside of 332 ice rinks located in nine countries. Each rink manager also completed a questionnaire describing the building, the resurfacing machines, and their use patterns. The (arithmetic) mean NO2 level for all rinks in the study was 228 ppb, with a range of 1-2,680 ppb, based on a sample collected at breathing height and adjacent to the ice surface. The mean of the second indoor sample (collected at a spectator's area) was 221 ppb, with a range of 1-3,175 ppb. The ratio of the indoor to outdoor NO2 concentrations was above 1 for 95% of the rinks sampled, indicating the presence of an indoor NO2 source (mean indoor:outdoor ratio = 20). Estimates of short-term NO2 concentrations indicated that as many as 40% of the sampled rinks would have exceeded the World Health Organization 1-hour guideline value of 213 ppb NO2 for indoor air. Statistically significant associations were observed between NO2 levels and the type of fuel used to power the resurfacer, the absence of a catalytic converter on a resurfacer, and the use of an ice edger. There were also indications that decreased use of mechanical ventilation, increased number of resurfacing operations per day, and smaller rink volumes were associated with increased NO2 levels. In rinks where the main resurfacer was powered by propane, the NO2 concentrations were higher than in those with gasoline-powered resurfacers, while the latter had NO2 concentrations higher than in those using diesel. Rinks where the main resurfacer was electric had the lowest indoor NO2 concentrations, similar to the levels measured outdoors.

Air Pollution, Indoor↗
PubMed1996

Association between electrocardiographic ischemic abnormalities and ischemic heart disease risk factors in a Japanese population.

This cross-sectional study was undertaken to investigate the association of electrocardiographic (ECG) ischemic abnormalities with ischemic heart disease (IHD) risk factors in a Japanese population. Resting ECGs of 1201 subjects (572 men and 629 women, aged 30 to 89 years), were coded independently by two coders according to the Minnesota Code. Blood pressure (BP) was recorded using a standard sphygmomanometer, and non-fasting serum total cholesterol and high-density lipoprotein cholesterol were measured. Codes 1.1 and 1.2 were classified as myocardial infarction and codes 1.3, 4.1-4.4, 5.1-5.3 and 7.1 were classified as ischemia. Prevalence of ECG with evidence of IHD (IHD ECG) was defined as myocardial infarction and ischemia together. Levels of risk factors were compared between subjects with IHD ECGs and those without IHD ECGs. Multiple logistic regression analysis was used to ascertain the associations between IHD ECG and risk factors. The prevalence of myocardial infarction in the total population was 1.5% and 0.7% in men and women, respectively and the prevalence of IHD ECGs was 10% and 11.3% in men and women, respectively. Systolic blood pressure (SBP) was consistently higher in subjects with IHD ECGs in the total population of both sexes (P < 0.001, P = 0.001 for men and women respectively). Diastolic blood pressure (DBP) was higher only in men with IHD ECGs (P = 0.002). In middle-aged men (aged 30-59 years), total cholesterol was considerably higher in subjects with IHD ECGs, although this relationship was statistically not significant. In multiple logistic regression analysis, SBP was independently associated with IHD ECGs in both sexes (P = 0.001). Associations between IHD ECGs with total cholesterol, alcohol intake and smoking were not statistically significant. This study showed that electro-cardiographic IHD evidences in Japanese are predominantly associated with blood pressure level in both sexes.

Adult↗
PubMed1995

[Carcinoma of the renal pelvis and ureter following bladder carcinoma].

We followed 135 primary bladder carcinoma patients for at least 3 years. Subsequent carcinomas of the upper urinary tract were found in 5 patients (3.7 per cent) an average of 67 months after an initial treatment of the bladder tumors. Two patients underwent radical cystectomy and the remaining 3 patients received transurethral resections or partial cystectomy five to seven times for bladder lesions. Primary bladder tumor was multiple in all and one of them was accompanied by carcinoma in situ in the bladder and urethra. Except for one patient who presented with gross hematuria, four patients had no symptoms referable to the upper urinary tract tumor. However two of them had high stage disease. Positive urinary cytology was observed in only one patient. All patients underwent nephroureterectomy and the four got well but one died of acute heart failure. Regular urinary cytology and IVP should be done for an extended period of time for early detection of renal pelvic and ureter cancers in patients who had multiple and recurrent bladder cancers.

Adult↗
PubMed1994

Attenuation of antifibrillatory effects of lidocaine by its metabolite, glycylxylidide: application of modulated receptor hypothesis.

Lidocaine, one of the drugs effective in treating ventricular arrhythmias in acute myocardial infarction (AMI), sometimes loses its efficacy after prolonged administration, possibly owing to the counteraction of glycylxylidide, one of the metabolites of lidocaine, through modulation of binding of lidocaine to sodium channels. To determine whether glycylxylidide interferes with the antiarrhythmic action of lidocaine, we compared the antifibrillatory effects of lidocaine, glycylxylidide, and their combination in 14 anesthetized open-chest dogs. Although glycylxylidide alone prolonged intraventricular conduction time (CT) and did not affect ventricular effective refractory period (VERP), it had different effects when added to lidocaine; i.e., it had no effect on intraventricular conduction time but shortened VERP. Although glycylxylidide alone did not change ventricular fibrillation threshold (VFT), the increase in VFT induced by lidocaine was decreased by addition of glycylxylidide, possibly as a result of competition for the same cardiac sodium channels between lidocaine and glycylxylidide with similar onset but different offset kinetics, which may explain, at least in part, the drug-resistance phenomena that ensue from prolonged lidocaine administration.

Animals↗
PubMed1994

Mechanism of interruption of atrial flutter by moricizine. Electrophysiological and multiplexing studies in the canine sterile pericarditis model of atrial flutter.

BACKGROUND: Moricizine is said to have potent effects on cardiac conduction but little or no effect on cardiac refractoriness. METHODS AND RESULTS: The effects of moricizine (2 mg/kg IV) on induced atrial flutter were studied 2 to 4 days after the creation of sterile pericarditis in 11 dogs. Ten episodes of stable atrial flutter before and after the administration of moricizine were studied in 9 dogs in the conscious, nonsedated state, and 7 episodes were studied in 6 dogs in the anesthetized, open chest state. In the conscious state, the effects of moricizine on atrial excitability, atrial effective refractory period, and intra-atrial conduction times were studied by recording during overdrive pacing of sinus rhythm from epicardial electrodes placed at selected atrial sites. Moricizine prolonged the atrial flutter cycle length in all the episodes, from a mean of 133 +/- 9 to 172 +/- 27 milliseconds (P < .001), and then terminated 7 of the 10 episodes. Moricizine increased the atrial threshold of excitability from a mean of 2.3 +/- 1.4 to 3.3 +/- 2.2 mA (P < .01) and prolonged intra-atrial conduction times (measured from the sulcus terminalis to the posteroinferior left atrium) from a mean of 58 +/- 6 to 64 +/- 5 milliseconds (P < .005). Prolongation of the atrial effective refractory period from 166 +/- 20 to 174 +/- 24 milliseconds (P < .05) was observed only at the sulcus terminalis site. In the open chest studies, administration of moricizine prolonged the atrial flutter cycle length from a mean of 150 +/- 15 to 216 +/- 30 milliseconds (P < .001) and then terminated the atrial flutter in all 7 episodes. As demonstrated by simultaneous multisite mapping from 95 bipolar sites on the right atrial free wall, the atrial flutter cycle length prolongation was either due to further slowing of conduction in an area of slow conduction in the reentrant circuit of the atrial flutter (5 episodes) or further slowing of conduction in an area of slow conduction plus the development of a second area of slow conduction (2 episodes). The change in conduction times in the rest of the reentrant circuit was negligible (10.9 +/- 8.7% of the total change). In all 7 episodes, the last circulating reentrant wave front blocked in an area of slow conduction. CONCLUSIONS: Moricizine (1) prolongs the atrial flutter cycle length, primarily by slowing conduction in an area of slow conduction in the reentrant circuit, (2) terminates atrial flutter by causing block of the circulating reentrant wave front in an area of slow conduction of the reentrant circuit, and (3) effectively interrupts otherwise stable atrial flutter in this canine model. The reason for these effects of moricizine are not readily explained by its effects on global atrial conduction times and refractoriness studied during sinus rhythm. Local changes in conduction in an area(s) of slow conduction are responsible for both cycle length prolongation and atrial flutter termination rather than the traditional wavelength concept of head-tail interaction.

Animals↗
PubMed1994

A quantitative estimation of electric current due to myocardial injury.

Myocardial injury causes electric current at the border of injured muscle and the surrounding intact region. In order to determine the magnitude of the injury current, experiments were performed with the isolated canine heart perfused with Tyrode's solution. The anterior descending branch of the left coronary artery was perfused selectively with high potassium (K+) solution and the resulting injury current was reflected in the ST shift of the orthogonal electrocardiogram, derived from the surface of a cubic container in which the heart was placed. After measurement of the ST vector with different K+ concentrations, the heart has fixed with formalin and the injury zone was delineated with serial sections. The boundaries of the selectively perfused region were reconstructed. The algebraic sum of orthogonal components of boundary surfaces determined the average direction normal to the boundary, which was found to be parallel with the ST vector. With increasing K+ concentrations, the ST shift became more marked. However, it was saturated at about 30 mEq/L K+. The maximum injury current, calculated from the saturated value of the ST magnitude, amounted to 0.10 mA.cm per unit area of the boundary surface. Additional experiments were performed with right ventricular papillary muscle preparations. Injuries were caused by a cotton pad containing high K+ solution placed in two directions to make the border along and across the long axis of the papillary muscle. The results indicate that the injury current in an anisotropic structure was essentially directed along the fiber orientation.

Aged↗
PubMed1993

Characterization of double potentials in a functionally determined reentrant circuit. Multiplexing studies during interruption of atrial flutter in the canine pericarditis model.

OBJECTIVES: We tested the hypothesis that double potentials recorded during atrial flutter in a functionally determined reentrant circuit reflect activation of the reentrant wave front around an area of functional conduction block. BACKGROUND: The center of the atrial flutter reentrant circuit in the sterile pericarditis canine model is characterized by double potentials. METHODS: We studied 11 episodes of atrial flutter in eight dogs during interruption of atrial flutter while pacing the atria. A multielectrode mapping system was used to record simultaneously from 190 electrodes on the right atrium (location of reentry). RESULTS: Interruption of atrial flutter occurred when the orthodromic wave front from the pacing impulse blocked in an area of slow conduction in the reentrant circuit. The response of the double potential with interruption of atrial flutter depended on the location of the recording site relative to this area of block. Two types of response were seen. When the double potential was recorded orthodromically distal to this area of block, interruption of atrial flutter was associated with disappearance of the second deflection, and continued pacing after interruption of atrial flutter was not associated with reappearance of the second potential. When the double potential was recorded at a site orthodromically proximal to the area of block, interruption of atrial flutter was not associated with disappearance of the second potential, and when rapid atrial pacing was continued, the double potential remained despite disappearance of the atrial flutter reentrant circuit. CONCLUSIONS: Double potentials represent functional conduction block in the center of the reentrant circuit, with each deflection of the double potential reflecting activation on either side of the area of functional block. The data also demonstrate that double potentials are not limited to a reentrant circuit, as they were recorded on either side of an area of block in the absence of such a circuit.

Action Potentials↗
PubMed1993

[A comparative study of the health conditions of elderly people living alone, elderly couples and the bedridden elderly at home in a rural area of Shiga Prefecture: special reference to morbidity rate and blood pressure, electrocardiograph and blood examination data].

For the purpose of obtaining basic data and for establishing a support system for elderly people with various health and social problems, a population survey was performed in 1990 to investigate the health and living conditions of elderly people living alone, elderly couples and the bedridden elderly in the town of Shigaraki, Shiga Prefecture. A total of 275 subjects (103 male, 172 female) 65 years of age and over were surveyed. The participation rate in this survey was 88.1%. Analysis of health conditions (morbidity rate, blood pressure, electrocardiograph and blood examination data) of elderly people living alone, elderly couples and the bedridden elderly produced the following: 1) Stroke was the main cause of being bedridden in men, while in women, bone and joint disease, especially fracture, was the main cause. 2) The combined prevalence of hypertension and borderline hypertension in elderly people living alone, elderly couples and the bedridden elderly was over 50%. The bedridden elderly had a lower prevalence than elderly people living alone and elderly couples. 3) Men in all of the above mentioned life styles, had a higher tendency of showing ECG abnormalities than women. The tendency for major ECG abnormalities was high for bedridden elderly, both male and female, with the tendency for men being higher. 4) In bedridden elderly, a tendency of higher prevalence of anemia, in both male and females, lower total serum cholesterol and triglyceride in males compared to elderly people living alone and in elderly couples, was observed.

Activities of Daily Living↗
PubMed1992

Role of sympathovagal interaction in diurnal variation of QT interval.

To elucidate the role of sympathovagal interaction in diurnal variation of QT interval, 24-hour ambulatory electrocardiographic recordings from 56 subjects (23 control subjects, 18 patients with atherosclerotic coronary artery disease, and 15 patients with diabetes mellitus) were studied. The QT interval at a heart rate of 60 beats/min (QT60) was determined for each of the day and night periods by regression analysis. Sympathetic and parasympathetic activities were assessed by spectral analysis of heart rate variability and represented by the low- and high-frequency components, respectively. The proportion of high-frequency component to the sum of low- and high-frequency components was used as an index of sympathovagal balance. The relative increase in QT60 at night (delta QT60 [%]) was larger in control subjects (4.2 +/- 2.1%) than in patients with coronary artery disease (2.2 +/- 1.8%; p less than 0.01) and diabetes mellitus (-1.5 +/- 4.0%; p less than 0.001). When the data from the 3 subject groups were pooled and analyzed, delta QT60 was correlated with the change in the sympathovagal balance (r = 0.554; p less than 0.001). Low-frequency component in the day alone was also related with delta QT60 (r = 0.554; p less than 0.001), but the ratio or difference of the high-frequency component value between day and night was not. These results indicate that although change in sympathovagal balance was responsible for the diurnal variation in QT interval, the enhanced sympathetic activity in the day was a major determinant of this phenomenon.

Aged↗
PubMed1992

Formation of glycine conjugate and (-)-(R)-enantiomer from (+)-(S)-2-phenylpropionic acid suggesting the formation of the CoA thioester intermediate of (+)-(S)-enantiomer in dogs.

It has been proposed that the chiral inversion of the 2-arylpropionic acids is due to the stereospecific formation of the (-)-R-profenyl-CoA thioesters which are putative intermediates in the inversion. Accordingly, amino acid conjugation, for which the CoA thioesters are obligate intermediates, should be restricted to those optical forms which give rise to the (-)-R-profenyl-CoA, i.e., the racemates and the (-)-(R)-isomers. We have examined this problem in dogs with respect to 2-phenylpropionic acid(2-PPA). Regardless of the optical configuration of 2-phenylpropionic acid administered, the glycine conjugate was the major urinary metabolite and this was shown to be exclusively the (+)-(S)-enantiomer by chiral HPLC. Both (-)-(R)- and (+)-(S)-2-phenylpropionic acid were present in plasma after the administration of either antipode, and further evidence of the chiral inversion of both enantiomers was provided by the presence of some 25% of the opposite enantiomer in the free 2-phenylpropionic acid and its glucuronide excreted in urine after administration of (-)-(R)- and (+)-(S)-2-phenylpropionic acid. The (+)-(S)-enantiomer underwent chiral inversion to the (-)-(R)-antipode when incubated with dog hepatocytes. These data suggests that both enantiomers of 2-phenylpropionic acid are substrates for canine hepatic acyl CoA ligase(s) and thus undergo chiral inversion, but that the CoA thioester of only (+)-(S)-2-phenylpropionic acid is a substrate for the glycine N-acyl transferase. These studies are presently being extended to the structure and species specificity of the reverse inversion and amino acid conjugation of profen NSAIDs.

Animals↗