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Biomedical subjects

I Nakasone

Publications and source records attributed to I Nakasone.

29 records · Page 2Linked to original sources
PubMed1996

[Estimation of right ventricular contractility by continuous-wave Doppler echocardiography].

The right ventricular dP/dtmax and relatively load-independent index, dP/dtmax/IP (IP: instantaneous pressure difference between the right ventricle and right atrium) can be measured from the tricuspid regurgitant velocity by continuous-wave Doppler echocardiography. The present study investigated these indices as measures of right ventricular contractility. Thirty-one patients were classified into three groups: 11 patients without right ventricular disease (control group), 9 with dilated cardiomyopathy and 1 with hypertrophic cardiomyopathy in the dilated phase (DCM group), and 10 with pulmonary hypertension (PH group). Right ventricular contractility was impaired in both the PH group and DCM group, but dP/dtmax was significantly larger in the PH group compared with the control group and DCM group (519 +/- 113 vs 249 +/- 66 and 234 +/- 78 mmHg/sec, p < 0.01). There was no significant difference between dP/dtmax in the control group and DCM group. dP/dtmax/IP in the PH group was smaller than the control group (31 +/- 8 vs 39 +/- 7/sec, p < 0.05) and larger than the DCM group (22 +/- 12/sec, p < 0.05). Mean New York Heart Association grading was 1.0 in the control group, 3.1 in the DCM group, and 2.8 in the PH group, respectively. Thus, dP/dtmax/IP, noninvasively obtained by continuous-wave Doppler echocardiography, may be a better index for evaluating right ventricular contractility than dP/dtmax.

Adult↗
PubMed1995

[Evaluation of multiple Pseudomonas aeruginosa strains with different characteristics in clinical specimens; combined results from serotyping, drug susceptibility and enzyme production].

Multiple Pseudomonas aeruginosa strains with different characteristics are occasionally isolated from a clinical specimen. Therefore, more than five isolated colonies of P. aeruginosa obtained at random from each clinical specimen (47 sputa, 18 urine, 10 pus and 8 others). These were investigated for serotype, drug susceptibility to eight antimicrobial agents and productivity of enzymes, such as protease and elastase. The specimens with multiple serotype colonies were shown in 17% of the sputa, 11% of the urine and 10% of the pus. 45.7% of the specimens with single serotype colonies exhibited more than two different patterns of enzyme productivity and so did 47.1% different patterns of drug susceptibility. Single serotype strains of P. aeruginosa with different characteristics of these tests were demonstrated in 81.3% of the urine, 73.6% of the sputum, 50.0% of the pus and 66.7% of others. We conclude that it is important to recognize the possible existence of multiple P. aeruginosa strains with different patterns of the enzyme productivity and drug susceptibility, regardless of single serotype, in clinical specimens.

Anti-Bacterial Agents↗
PubMed1990

[Nosocomial infection with methicillin-resistant Staphylococcus aureus].

Methicillin-resistant Staphylococcus aureus (MRSA) isolated in our hospital between 1986 and 1989 were mainly examined for their susceptibility to various antibiotics and coagulase types. The isolation frequency of MRSA among S. aureus isolated from clinical specimens has been steadily increasing; 37.8% in 1986, 49.8% in 1987, 60.6% in 1988 and 63.2% in 1989. This trend was particularly noticeable in the specimens associated with the respiratory tracts. The isolation rate of MRSA in the surgery and pediatrics wards was higher than that in the internal medicine ward. More than 80% of MRSA were coagulase type II, which were multi-resistant to penicillins, cephems, aminoglycosides and macrolides, and sensitive to MINO, new quinolones and VCM. These epidemic strains were also isolated from the nose of medical staff and from air samples in the wards. These findings suggest that the hospital environment including the patients and hospital personnel is extensively contaminated with multi-resistant MRSA of coagulase type II. Measures should be taken for prevention and control of nosocomial infection with MRSA in the whole hospital.

Air Microbiology↗
PubMed1988

[In vitro susceptibilities of clinical isolates of Staphylococcus aureus].

In vitro susceptibilities of 350 strains of Staphylococcus aureus to ampicillin (ABPC), methicillin (DMPPC), cloxacillin (MCIPC), cefazolin (CEZ), cefmetazole (CMZ), cefmenoxime (CMX), latamoxef (LMOX) and 5 non-beta-lactam antimicrobial agents were determined according to the standard method of Japan Society of Chemotherapy. Frequencies of the appearance of resistant organisms (MIC greater than or equal to 12.5 micrograms/ml) to beta-lactam antibiotics were 45% for ABPC, 27% for DMPPC, 11% for MCIPC, 24% for CEZ, 15% for CMZ, 36% for CMX and 51% for LMOX. To non-beta-lactam antimicrobial agents, resistant strains appeared at 31% to gentamicin, 15% to amikacin, 0.6% to minocycline (MINO), 1% to norfloxacin (NFLX) and 65% to fosfomycin (FOM). More than 80% of DMPPC-resistant strains were also resistant to LMOX, CMX, ABPC, FOM, and CEZ, but most of those were susceptible to MINO and NFLX. Incidence of DMPPC-CEZ resistant S. aureus was 23% of the 350 strains tested. As stated above, multiply resistant strains of S. aureus are present throughout different hospitals in Okinawa.

Ampicillin↗
PubMed1985

[Mitral regurgitation: detection and quantitative evaluation by two-dimensional Doppler echocardiography].

Mitral regurgitation was detected and quantitatively evaluated using two-dimensional Doppler-echocardiography. The subjects consisted of 74 cases having a variety of heart diseases, who underwent left ventriculography within one week before or after the Doppler study. Among 50 patients with mitral regurgitation confirmed by left ventriculography, the Doppler study detected mitral regurgitant flow signals in 46, for a sensitivity of 92%. Minimal mitral regurgitation in four cases could not be detected by Doppler studies. Twenty-four patients had no mitral regurgitation according to left ventriculography; all but one also had no mitral regurgitation by Doppler study, for a specificity of 96%. In one false positive case, typical mitral regurgitant flow signals were detected in an area localized within the left atrial cavity near the mitral valve orifice. The possibility remains that left ventriculography missed this minimal regurgitation. For quantitative assessment of mitral regurgitation, the following two methods were used. Three long-axis views through the lateral, middle and medial parts of the mitral valve, and a short-axis view at the level of the mitral orifice were imaged via the parasternal approach. The area where mitral regurgitant flow signals were detected was mapped on each cross-sectional echocardiogram, then the distance attained by the regurgitant flow from the mitral valve and the area covered by the regurgitant flow were determined. The maximal distance among the three long-axis views and the sum of the distances in these views was parallel to the severity of mitral regurgitation as assessed by left ventriculography.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1984

Augmentation of atrial contribution to left ventricular inflow with aging as assessed by intracardiac Doppler flowmetry.

The influence of aging on the left ventricular (LV) function in diastole was investigated from the aspect of the mitral inflow pattern using 2-dimensional Doppler echocardiography. The subjects for the investigation were 69 persons who were diagnosed as healthy by a checkup examination. The peak velocity in the rapid filling phase and that in the atrial contraction phase tended to decrease and to increase with aging, respectively. However, these tendencies were not statistically significant. However, the ratio of the atrial contraction phase to the rapid filling phase showed a significant increase with aging (r = 0.82, p less than 0.001). Therefore, it is considered that the mitral flow conditions are influenced by aging. The result obtained is also interpreted to mean that the LV distensibility in early diastole is impaired with aging and that the contribution of the atrial contraction to LV filling is compensatorily augmented.

Adult↗
PubMed1984

[Noninvasive determination of the ratio of pulmonary to systemic blood flow with two-dimensional Doppler echocardiography: efficacy and limitation].

Noninvasive determination of the ratio of the pulmonary to systemic blood flow (Qp/Qs) was attempted in 31 cases with intracardiac shunt using two-dimensional pulsed Doppler echocardiography. The Qp/Qs of these cases was ranged from 0.99 to 4.55 with an average of 2.63 by cardiac catheterization. Technical problems in the measurement were also studied. Seventeen cases with no shunt were served as controls. Systemic and pulmonary flow volumes, Qp and Qs (ml/min), were calculated by the following equation: Q (ml/min) = mean flow velocity (cm/sec) X cross sectional area of the semilunar valve ring (cm2) X 60 Here, the sample volume was set in the center of the valve ring at the phase when the flow velocity attained its peak in a pulse period. The mean velocity was obtained by dividing the integration of instantaneous mean frequency in the sample volume for a pulse period by RR interval. The ultrasonic incident angle was measured on the echocardiogram. The velocity profile at the valve ring was assumed to be a plane wave. The diameter (D) of the valve ring was measured on the echocardiograms of the long-axis view of the outflow tract. To make a correction referring to the value obtained by angiocardiography, 0.22 cm was added to the value obtained on the echocardiogram (D). The cross sectional area of the valve ring was calculated according to the following formula: Cross sectional area (cm2) = pi X [(D + 0.22/2)]2 The Qp/Qs ratio by the Doppler method in the cases with no intracardiac shunt was 1.11 (S.D. = 0.21) on an average and the Qp/Qs in the cases with an intracardiac shunt was well correlated with that by catheterization (r = 0.82). These results suggested the feasibility of the clinical application of the Doppler method for noninvasive determination of Qp/Qs. In 17 cases, pulmonary and systemic flow volumes measured by the direct Fick method were compared with those by the Doppler method, respectively. Considerable differences were observed between them. There was a tendency that both pulmonary and systemic flow volumes were under-estimated by the Doppler method in cases with a large shunt.(ABSTRACT TRUNCATED AT 400 WORDS)

Blood Circulation↗
PubMed1981

[Blood flow analysis with pulsed echo Doppler cardiography in valvular pulmonary stenosis (author's transl)].

Blood flows in the main pulmonary artery, right pulmonary artery and right ventricular outflow tract were analyzed in 11 cases of valvular pulmonary stenosis and 10 healthy subjects by pulsed echo Doppler cardiography (two-dimensional) with the parasternal and suprasternal approaches. 1) The systolic flow in the right pulmonary artery was detected in 7 cases of valvular pulmonary stenosis, in which the flow of both right and main pulmonary arteries was detected in only one case. The flows seemed to be turbulent. These abnormal signals were never detected in healthy subjects and considered to be caused by the narrowing of the pulmonic orifice. 2) Abnormal flow signals were also detected in the right ventricular outflow tract in patients of pulmonary stenosis. Their features were as follows: (1) A systolic turbulent flow was detected in a case with severe hypertrophy of the wall and narrowing of the lumen of the right ventricular outflow tract. (2) A/S ratio, which is a ratio of the peak velocity in atrial contraction (A) to the peak velocity in systole (S), was larger in cases with pulmonary stenosis than in healthy subjects (p less than 0.05). It was considered that the atrial component in the right ventricular filling was augmented in pulmonary stenosis. (3) The PEP/ET (pre-ejection period/ejection time) of the right ventricle was smaller in cases with pulmonary stenosis than in healthy subjects (p less than 0.05). The ratio exhibited a reverse correlation with the pressure gradient between the right ventricle and pulmonary artery (r = 0.74, p less than 0.025). (4) Acceleration time index, a ratio of the time interval between the upstroke and the peak velocity of ejection flow to the ejection time, as a parameter indicating the time delay of the peak velocity exhibited a significant correlation with the pressure gradient between the right ventricle and pulmonary artery (r = 0.67, p less than 0.05). (5) No correspondence was revealed between the time interval of Q-peak velocity in systole and that of Q-peak intensity of the murmur during systole. It was remained to be clarified.

Adult↗
PubMedDate not supplied

[Diagnosis of coronary artery dehiscence and pseudoaneurysm after modified Bentall operation by Doppler color flow imaging: a case report].

This 48-year-old man presented with anterior chest and back pain in 1981. He was treated with replacement of the ascending aorta and aortic valve under a diagnosis of dissection of the ascending aorta with severe aortic regurgitation. He underwent modified Bentall reoperation for the dilation of the aortic root in 1991. Postoperative two-dimensional echocardiography was performed because of sustained atrial flutter. An echo-free space was detected between the aorta graft and aorta wrapping on the short-axis view. Doppler color flow imaging revealed blood flow from the left coronary artery graft into the echo-free space. This leakage was suspected to be the cause of the echo-free space. Transesophageal echocardiography was performed to conform this hypothesis, which revealed blood flow from the left coronary artery graft into the echo-free space in systole and flow into the left coronary artery graft from the echo-free space in diastole.

Anastomosis, Surgical↗