Biomedical subjects
Publications and source records attributed to S Ohkawa.
The haemagglutinin-neuraminidase gene of Newcastle disease virus was inserted into a non-essential region of the fowlpox virus genome and expressed under control of the vaccinia virus 7.5 kDa polypeptide gene promoter. Immunization with the recombinant fowlpox virus elicited protective immunity in chickens against both virulent Newcastle disease and fowlpox virus infection.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
A parameter study with use of the finite element method was conducted for examination of the relationships between the shape parameters of a clasp (width and thickness at the base and tip of the clasp) and its displacement or stress. By synthesis of these relationships, a simple formula defining the clasp tip displacement in terms of clasp dimensions ("displacement formula") was obtained. A stiffness parameter "Fd" (the load producing a 1-mm displacement of the clasp tip) was proposed, and a formula defining Fd in terms of shape parameters was derived from the displacement formula. Fd would be a practical parameter for the definition of clasp retention, and the present formulae appear to be useful tools for investigation of the retention of removable partial dentures.
In order to establish diagnostic and treatment system for temporomandibular (TM) disorder patients, data were collected on mandibular border and tapping movements at incisive point and compared with those from the subjects without any TM disorders. Significant differences on the ratio of left and right sides of maximum lateral deviation, maximum opening amount and length of pathway of lateral border movement were clearly obtained, the values of maximum speed and acceleration of closing phase in tapping movement obtained from TM disorder patients were also different significantly from those in the control subjects. These findings suggests that those measured indices in this study would be useful for diagnosis of TM disorders.
Seven elderly patients with hypertrophic obstructive cardiomyopathy (HOCM), who had the three following characteristics on echocardiograms 1) extremely thickened septum, 2) systolic anterior motion of the mitral valve, 3) mid systolic semi-closure of the aortic valve, were clinically evaluated. Ages ranged from 73 to 86 years old (average 78.9% yr.) and all were women. None had not a family history of hypertrophic cardiomyopathy but they had mild hypertension. Six patients showed a significant high voltage on the ST-segment and T-wave abnormalities ("strain" pattern). The left ventricular posterior wall as well as the septum was thickened in 5 and the remaining 2 showed asymmetrical septal hypertrophy (ASH) on echocardiograms. The left ventricular cavity was narrowed due to left ventricular hypertrophy and the shape of the left ventricular cavity was ovoid in all patients. The aorto-septal angles in these 7 patients were 80 degrees to 120 degrees. In addition, proximal septal bulge in all and anterior displacement of the mitral posterior leaflet due to the mitral ring calcification (MRC) in some patients contributed to the narrowing of the left ventricular outflow tract, and the mitral valve was pulled up toward the septum because of the good left ventricular systolic function (ejection fraction: 70 to 94% by echocardiography) and blood was ejected at a high velocity through a narrowed outflow tract (Venturi effect). Pressure gradients in the left ventricular outflow tract was 38 to 146 mmHg in 5 examined by cardiac catheterization. Biopsy specimens were obtained from 2 patients, showing hypertrophic myocytes (diameter: 20 to 30 micron) in 2 and mild disarray in 1.(ABSTRACT TRUNCATED AT 250 WORDS)
A circumferential profile analysis with a two-dimensional polar representation of thallium(Tl)-201 myocardial single photon emission computed tomograms (SPECT) is an objective and quantitative method to evaluate myocardial infarction (MI). However, the diagnostic capability depends on the normal range of thallium distribution. Therefore, the quantitative analysis of Tl-201 myocardial SPECT was correlated with the pathological findings of the heart in 50 autopsy cases (28 with MI; 22 without MI) to determine the lower normal limits at which we can precisely determine the extent of MI on a quantitative basis. For correctly detecting the extent of MI, the lower normal limits were 2.5 standard deviations below the mean values calculated using profiles normalized to the maximum pixel count observed in each profile. Using this lower normal limit, the sensitivity was 63.8%; specificity was 87.4%; and accuracy was 80.7% for determining the extents of ischemic lesions, though these values were lower than those obtained by visual analysis. However, for detecting MI, the sensitivity by quantitative analysis was 97% which was higher than that by visual analysis. A medium sized (2.5 cm) non-transmural infarction, undetectable by visual analysis, was detectable by two-dimensional polar representations. However, the specificity of detecting MI was low (59%), and most of the false positive studies were observed in cases of valvular disease, coronary artery disease or other cardiac complications. The detectability of the extent of MI varied according to the location of the lesion. False negative lesions were most frequently observed in the septal region; false positive lesions were most frequently observed at the posterolateral regions of the dilated hypertrophic hearts. The septal region located at the peripheral portion of the MI and septal hypertrophy in cases of hypertension, were the likely negative cases, thus, these pathological characteristics may explain the high incidence of false negative results in the septal region quantitatively as well as by visual analysis. In cases with dilated hearts, the radioactivity of the thallium at the posterolateral region was more reduced by absorption compared with that in the non-dilated hearts. This reduction in counts was empirically regarded as abnormal lesions by visual analysis, however, the same situation can objectively and automatically be recognized as false positive by quantitative analysis. We concluded that quantitative analysis by Tl-201 myocardial SPECT is useful for evaluating myocardial infarction automatically, but care must be exercised concerning possible false positive diagnosis in cases with dilated hypertrophic hearts.
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Transverse strength and acoustic emission (AE) characteristics were measured by the transverse test in deionized water at 37 degrees C on commercial denture base resins (five heat-cured type resins and one polysulfone). Difference in flexural property of five heat-cured denture base resins was not shown from the transverse deflection according to JIS, but high toughness of polysulfone was recognized in transverse deflection, flexural strength, flexural modulus, flexural rigidity, flexural proof stress, and fracture energy. The five heat-cured denture base resins showed a low AE activity, but the polysulfone resin high AE activity. Significant rates of AE for polysulfone were detected at a kgf of approximately 50-60% the maximum load. The presence of Kaiser effect in its cycle transverse test was confirmed.
The application of surface electromyography as an aid in diagnosing craniomandibular dysfunction requires that pathological or treatment-induced changes of the EMG be distinguished with sufficient probability from random variations due to methodological or biological reasons. It was the aim of this study to determine the range of variability of elevator muscle EMG, to find experimental methods for improving reproducibility, and to establish evaluation procedures that allow the recognition of treatment-induced effects in the EMG even in the presence of great random variations. For this we measured the voltage/tension relation of the elevator muscles of 42 persons in the range of 20 to 500 N on up to 20 different days under constant experimental conditions. The majority of measurements revealed a non-linear correlation between EMG activity and resulting force, hence second order polynomials proved to be more appropriate than straight lines for representing the activity/tension correlation. Muscle activity was found to vary randomly from day to day within each individual. These fluctuations appeared as varying axis intersections, initial slopes and curvatures which are the determinants of the voltage/tension curves. In ten selected subjects random fluctuations were significantly higher when electrodes were repositioned by palpation of the muscle belly than with the aid of tattoos.
In part II, a method is described which reduced the variations of the three determinants of the voltage/tension curves to the fluctuation of only one three dimensional variable. A way to estimate three dimensional regions for the fluctuations is shown. For a given level of significance, limits can be calculated that allow us to decide whether differences between post- and pre-treatment measurements are random or due to treatment.
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We encountered two patients with right middle cerebral artery infarction who showed a unique eye sign not described so far. Both had suddenly developed central facial weakness, hemiplegia and hemisensory deficit in the left side. Anosognosia for the left hemiplegia, motor impersistence and left unilateral spatial neglect were also present. Initially they showed difficulty in keeping their eyes closed to the same degree on both eyes. However, this symmetrical motor impersistence of eye closing developed into a differential pattern over the days. Thus, on verbal command to close the eyes, the right eye in the non-paretic side would be closed continuously and excessively and in the left eye in the paretic side would be closed slightly and impresistently. This dissociation of eye closure was not observed in spontaneous eye closure. This symptom is close to the contralateral motor impersistence of eye closure which has been attributed to the right hemispheric lesion. But the concurrence of the ipsilateral overcontraction of the orbicularis oculi has not been described to the authors' knowledge. We proposed a hypothesis on this unique right-left dissociation of eye closing behavior.
Sixteen cases of mitral valve prolapse (MVP) with mitral regurgitation (MR) in the aged (mainly in their eighth and ninth decades) with both clinical and pathological evidences were investigated. One hundred autopsy cases served as the control. The longitudinally-sectioned mitral annulus fibrosus was pathologically studied in all with special reference to the atrium-valve disjunction reported by Hutchins. Morphologically, the mitral annulus fibrosus was classified either as type A (the mitral valve attaches to the left ventricle), type B (the mitral valve attaches to the left atrium: Hutchins' disjunction), type C (the atrialis continues to the left atrium and the fibrosa to the left ventricle), or type D (mitral annulus calcification). Type B was observed in only 31% of the MVP cases, whereas it was seen in 43% of the control cases. It was concluded that Hutchins' observation could not be regarded as the characteristic pathological finding of MVP.
Eighteen cases with bladder tumors were examined by means of superconducting MRI. Sequences used were spin echo (TR/TE (msec) = 500/20 as T1WI (weighted image) and 1500/80 as T2WI) and serial "fast spin echo (fast SE)" pre/post Gd-DTPA administration. "Fast SE" was a new technique offering a distinct T1WI (TR/TE = 100/14, utilizing a 14 second breath hold). Slice thickness of "fast SE" was 10 mm and slice plane was selected perpendicular to the tumor base to detect the extent of invasion. Serial scan of "fast SE" was performed before and immediately after 0.1 mmol/kg Gd administration. Scanning was completed before the bladder was opacified by Gd. Tumor and normal mucosa were both markedly enhanced whereas the surrounding muscle layer remained hypointense. On delayed scan, the elevated character of the tumor was outlined by opacified urine but the distinction between the mucosa and the muscle layer became unclear. Total cystectomy (TC) was performed in 6 of 18 cases and pathological tumor extension was correlated with MR findings. Transurethral resection (TUR) was performed in the remaining 12 patients, and the tumor extension was assessed by follow-up biopsy after TUR. Intact liner hypointensity indicated superficial lesions (= less than pT2), while disruption of the linear hypointensity corresponded pathologically to deep muscle invasion (= greater than pT3a). Accuracy of serial "fast SE" in tumor staging was 94% (17/18). Serial "fast SE" allowed the distinction of superficial from invasive tumors more accurately than conventional studies, and therefore assisted in choosing the correct operative method.
A vaccine against human immunodeficiency virus (HIV) would be highly effective in stopping the acquired immunodeficiency syndrome (AIDS) epidemic. A comprehensive evaluation of potential vaccine methodologies can be made by means of the simian model for AIDS, which takes advantage of the similarities in viral composition and disease potential between simian immunodeficiency virus (SIV) infection of rhesus macaques and HIV infection in humans. Immunization with a formalin-inactivated whole SIV vaccine potentiated with either alum and the Syntex adjuvant threonyl muramyl dipeptide (MDP) or MDP alone resulted in the protection of eight of nine rhesus monkeys challenged with ten animal-infectious doses of pathogenic virus. These results demonstrate that a whole virus vaccine is highly effective in inducing immune responses that can protect against lentivirus infection and AIDS-like disease.