Biomedical subjects

A Seo

Publications and source records attributed to A Seo.

At least 19 recordsLinked to original sources

PubMed2001

Measuring lower leg swelling: optimum frequency for impedance method.

The optimum measuring frequency of the impedance plethysmograph is determined for the estimation of leg volume increase caused by a sitting work load. Ten subjects sit for 1 h without leg movement. Right calf impedance is measured by the four-electrode method. The detecting electrodes are fixed on the calf with an inter-electrode distance of 15 cm. The measuring frequencies are 5, 10, 50 and 100 kHz. As the indices of leg swelling, three values are calculated: percentage change in impedance, volume change and percentage change in volume. The mean, standard deviation and coefficient of variation (CV) are calculated from the mean values of indices for each subject and frequency. The CV of all three indices increases when measurements are taken at higher frequencies. Among the three indices across all measuring frequencies, the volume change shows the highest CV (0.42 at 5 kHz, 0.82 at 100 kHz), and the percentage change in impedance shows the lowest CV (0.32 at 5 kHz, 0.72 at 100 kHz). It is concluded that the measuring frequency of 5 to 10 kHz is the best to obtain accurate data for the evaluation of lower leg swelling.

Adult↗

PubMed2001

Melt agglomeration with polyethylene glycol beads at a low impeller speed in a high shear mixer.

This study was performed in order to evaluate the possibility of obtaining spherical agglomerates with a high content of meltable binder by a melt agglomeration process in a high shear mixer. Lactose monohydrate was melt agglomerated with polyethylene glycol (PEG) 1500 or 6000 in a 10-l high shear mixer at an impeller speed of 400 rpm. The PEG 1500 was used as a size fraction of beads, and the PEG 6000 as a fine powder, a powder, unfractionated beads, and size fractions of beads. It was found to be possible to incorporate a high amount of PEG (28% m/m of the amount of lactose), because the rather low impeller speed applied in the present experiments caused less densification of the agglomerates. The fine powder of the PEG 6000 caused a complete adhesion of the mass to the bowl shortly after melting. A rapid agglomerate growth by coalescence was found to be the dominant growth mechanism when agglomeration was performed with the PEG 6000 powder. The PEG beads resulted in a slow and more controllable agglomerate growth, because the growth occurred primarily by an immersion of the lactose particles in the surface of the molten binder droplets. The initial shape of the agglomerates produced with the PEG beads was similar to the spherical shape of the beads. This shape could not be maintained during the process due to a breakage of the agglomerates caused by a hollow structure of the PEG beads.

Microspheres↗

PubMed2001

[Percutaneous cryosurgery for liver tumors].

A new cryoprobe developed in our department makes it possible to perform percutaneous cryoablation for small liver tumors. This cryoprobe is placed into each lesion using an ultrasonic guidance technique. In this study there were 10 patients with hepatocellular carcinoma and 5 patients with liver metastases from colorectal carcinoma. In 6 cases the tumor size was below 2 cm, in 6 cases between 2 and 3 cm, and in 3 cases over 3 cm. Using a cryoprobe of 3 mm in diameter, each lesion was frozen using liquid nitrogen for 15 or 20 minutes then thawed for 10 minutes, and repeated. The ice ball was found to enlarge to 3 cm in 20 minutes and 5 cm in 60 minutes experimentally. Six cases were CR, 5 PR, 2 NC and 2 PD. After cryoablation, liver function did not change and there were no complications. However, as the size of the ice ball was small (about 3 cm), this method was insufficiently effective in some cases. Percutaneous cryoablation using this probe should be performed for tumors smaller than 3 cm.

Aged↗

PubMed2000

NMR microscopy of the uptake, distribution and mobility of dissolution media in small, sub-millimetre drug delivery systems.

NMR techniques were used to study the drug release process from small (sub-mm) lipophilic matrix theophylline beads. NMR microscopy was used to follow the ingress of the dissolution medium into the beads. Pulsed gradient spin echo (PGSE) NMR and 3D NMR imaging were used to measure the mobility and distribution of liquid within fully liquid penetrated beads. These techniques were used to rationalise the increase in the drug release rate with increasing proportion of GMS (glycomonosaccharide):paraffin in the matrix composition. A well-defined penetrant front was seen to move towards the centre of the bead during the dissolution process and the rate of liquid uptake showed the same trend with increasing GMS content as the rate of drug release. The total concentration of absorbed liquid increased and its T(2) relaxation time decreased with increasing GMS content of the bead matrix. This combined with the interpretation of PGSE results suggested that liquid resides in the matrix material as well as in pores left by the dissolved drug, and that this tendency increases with increasing GMS content. Heterogeneities in liquid distribution within the beads were quantified using percolation analysis and were related to the lipid matrix composition and may be a contributory factor in determining the rate of drug release.

Algorithms↗

PubMed2000

Efficacy of long-term azathioprine for relapsing nephrotic syndrome.

Seven patients who had an initial attack of nephrotic syndrome in childhood and had frequent relapses even after cyclophosphamide therapy were given a 2-year course of azathioprine. The mean annual relapse rates decreased from 2.4+/-0.5 in the year preceding azathioprine to 0.4+/-0.8 in the 1st and 2nd years after its initiation. All six patients who were observed for more than 6 months after discontinuation of the therapy were relapse free for this period. Average doses of prednisolone could also be decreased in the 2nd and subsequent years after the therapy. There were no significant toxic effects. Long-term azathioprine therapy may be well tolerated and effective for nephrotic patients with frequent relapses.

Adolescent↗

PubMed2000

[Graft replacement of transverse aortic arch using the arch vessels first technique].

In surgical treatment of aortic arch aneurysm or aortic dissection, we have been employing retrograde cerebral perfusion (RCP). In the present study, we have developed "arch vessels first technique" to shorten perfusion time and achieved an excellent clinical outcome. The surgical procedure "arch vessels first technique" is outlined as follows. RCP is initiated following circulatory arrest, while a woven dacron graft (12 mm in diameter, the dacron graft must be prepared in advance) with two side arms (12 mm in diameter, i.e., with the same diameter) is anastomosed left subclavian artery, left common carotid artery and right brachiocepharic artery in a sequential manner. Then, brain circulation is initiated via one end of the dacron graft. Subsequently, in patients with aortic dissection, a 26 mm woven dacron tubular prosthesis is inserted, using an elephant trunk procedure, to perform "distal anastomose". A partial clamp is applied to the 12 mm woven dacron graft mentioned above, while this 26 mm graft is anastmosed to the 12 mm woven dacron graft side to side, thus reinitiating systemic circulation. While rewarming, the 26 mm woven dacron tubular prosthesis is proximal anastomosed. Mean RCP time was 79.4 minutes, using the conventional procedure "aortic arch distal anastomose", whereas the RCP time was shortened by this procedure "arch vessels first technique", as evidenced by mean RCP time of 57 minutes for patient with aortic dissection and of 39 minutes for patient with saccular aneurysm.

Aged↗

PubMed1999

Enhancement of B7-1 (CD80) expression on B-lymphoma cells by irradiation.

Irradiation of A20.2J mouse B-lymphoma cells enhanced their antigen-presenting ability to induce interleukin-2 (IL-2) production by 42-6A T cells specific for ovalbumin (OVA)323-339/I-Ad. Irradiated and fixed A20.2J cells were more efficient antigen-presenting cells (APC) to present OVA323-339 peptide than the unirradiated and fixed cells. Irradiation selectively increased the expression of B7-1 molecules, but not of the major histocompatibility complex class II molecules, B7-2, lymphocyte function-associated antigen-1, or intracellular adhesion molecule-1. Irradiation of A20.2J cells with 100 Gy followed by overnight incubation was optimal for the enhancement of B7-1 expression. Anti-B7-1 monoclonal antibody inhibited the irradiation-induced enhancement of APC function. Irradiation of A20.2J cells induced the accumulation of B7-1 mRNA. Thus, it was concluded that the enhancement of APC function by irradiation was due to the up-regulation of B7-1 molecules through the accumulation of its mRNA. Although partial inhibition of protein synthesis has been shown to enhance the accumulation of B7-1 mRNA and its expression, irradiation did not decrease the protein synthesis in A20.2J cells. The incubation with irradiated A20.2J cells stimulated unirradiated A20.2J cells to increase B7-1 expression, suggesting that irradiation of A20.2J cells induced expression or secretion of some molecule(s) to enhance B7-1 expression.

Animals↗

PubMed1999

[Estimation of left internal thoracic artery flow reserve after coronary artery bypass grafting using Doppler flow wire].

The usefulness of the left internal thoracic artery (LITA) for aortocoronary bypass grafting is now established. Reports of variation in LITA graft function are rare. Graft flow was measured using a Doppler flow wire to estimate graft function in 27 patients (24 males, 3 females) who underwent LITA grafting to the left anterior descending artery. Patients were classified into the following 3 groups: Group A consisted of 9 patients with normal left ventricular function and no native flow; Group B consisted of 11 patients with normal ventricular function and good native flow; Group C consisted of 7 patients with abnormal left ventricular function and no native flow. LITA graft function was also estimated 1 year after operation in 12 of these 27 patients (4 in each group). Diastolic/systolic velocity ratio (DSVR) and flow reserve were determined in the proximal, middle, and distal portions of the LITA graft and native left anterior descending artery before and after papaverine administration (8-10 mg). DSVR was significantly higher in the distal portion than in the proximal portion (p < 0.01), but this value did not change after papaverine administration. After 1 year, DSVR in the proximal portion was significantly higher in Group C than in Groups A or B (p < 0.05 for both). Four weeks after operation, the flow reserve of the distal portion was significantly higher in Group A than in Group C (p < 0.001). After 1 year, this value was significantly higher in Group A than in either Groups B or C (p < 0.01, p < 0.001, respectively). The rate of increase in flow reserve in the distal portion was significantly greater in Group A (23.4%) than in groups B (2.53%) or C (1.94%; p < 0.05 for both). The distal portion of the LITA was the best measurement site, since the flow pattern in the LITA graft varied throughout all portions. Diastolic flow velocity in the LITA graft was dominant in patients with myocardial damage. The results indicate that flow reserve of the LITA graft depends on antegrade native coronary flow and distal myocardial damage.

Coronary Artery Bypass↗

PubMed1999

[Surgical repair of postinfarction ventricular septal defect: modified Komeda-David procedure].

Since Cooley first reported surgical repair of postinfarction ventricular septal defect in 1957, there have been technical improvements in this procedure. However, the outcome of surgery has not been gratifying thus far. In 1990, Komeda and associates reported a single patch of bovine pericardium sutured to the healthy myocardium around the infarcted area on the left side of the septum that excludes the infarcted myocardium from the left ventricular cavity; a procedure based on a completely different idea. Since the satisfactory outcome of the surgical treatment in this procedure was obtained in a series of 12 patients, this surgical procedure has been in widespread use in Japan. On the other hand, this procedure has a drawback that there is a difficulty in suturing the patch and may lead to a postoperative residual shunt. We investigated a modified surgical procedure that could overcome this difficulty and would like to report it in this paper. At first, the perforated area should be covered with a felt strip and closed with mattress sutures. Secondly, the infarcted myocardium from the left ventricular cavity should be obliterated using a two-patch method. The primary advantage of this procedure is that it achieves a broader range of vision than a single patch method and enables easy suturing. Additionally, the development of a residual shunt can be prevented owing to the closure of perforation even if sutures fail to hold and leakage occurs. The tow-patch method has the advantage of avoiding tension against sutures since the patch is not everted around the sutures. However, the question arises whether only the healthy myocardium can be picked out and sutured without fail. In order to make the two-patch method more reloable the perforation should be closed in advance.

Aged↗

PubMed1998

[Load on the low back of teachers in kindergartens].

In order to evaluate the load on the low back of teachers in kindergartens, basic activity and working posture were analyzed for four teachers by means of video recording. The trunk inclination angle (TIA) was also measured continuously during full workshifts for 12 kindergarten teachers by means of an inclination monitor. The kindergarten teachers spent 67% of the workshift on activities in contact with children, "indoor group childcare", "indoor free playing", "outdoor childcare", "preparation and clearing away" and "help and care", and did not take a recess during the workshift. They spent 36% of the workshift in three working postures with the load on the low back, "standing bent forward", "squatting" and "kneeling". Cumulative time at a TIA of 20 degrees or more represented 43% of the workshift. The frequency of trunk-lifting from severe bending forward (TIA > 45 degrees) was 95 times/hr on average. A comparison of the kindergarten teachers and nursery teachers in 4-5 year age classes showed that the time distributions of basic activities were generally similar to each other. Although the time distributions of working postures were also similar, time spent "standing bent forward", "squatting" and "kneeling" was longer in the kindergarten teachers than in the nursery teachers. Cumulative time at a TIA of 45 degrees or more was significantly longer in the kindergarten teachers. Although the frequency of trunklifting was not significantly different, the kindergarten teachers tended to lift their trunk more frequently. The present study found that the load on the low back was considerably great in the kindergarten teachers.

Adult↗

PubMed1998

[An experience with St. Jude medical prosthetic 19A-HP which resulted in restricted opening at an early stage after operation].

St. Jude medical hemodynamic plus series is positively used for aortic valve replacement (AVR) of small orifice because it can increase the orifice area by 26% compared with conventional prosthetic valves of the same size. We performed AVR with SJM 19A-HP on a patient having aortic stenosis with regurgitation using horizontal mattress suturing technique. The aortic orifice size was 18.9 mm at the preoperative measurement. The course after the operation was uneventful until 9 days after the operation when cinefluoroscopy revealed symmetrical restriction of opening of valve leaflets. We are now monitoring the clinical course at the patient has not developed any symptoms though the LV-Ao pressures gradient is 60 mmHg by Doppler echocardiography. As the restriction of valve leaflet opening was symmetrical, it is not likely that an excess of the ligature or remnant caused the restriction; structural problems of St. Jude medical prosthesis appear to be a more reasonable explanation. Since the orifice ring of this prosthesis is not reinforced, longitudinal forces applied to the hinge may alter the shape of the ring, thus restricting the movement of valve leaflets. In the present case, forced insertion of 19A-HP instead of more desirable 17-HP is considered to have caused longitudinal forces acting on the hinge.

Aged↗

PubMed1998

[Operation for left renal cell carcinoma complicated with acute pulmonary tumor embolism and cocurrent removal of tumor].

The prognosis of pulmonary tumor embolism is said to be poor and only a limited number of patients with this disease have survived. The patient was a 64-year-old male suffering from left renal cell carcinoma complicated with tumor extending from the left renal vein to the inferior vena cava. The patient underwent an operation for left renal cell carcinoma during which he developed tumor embolus to the pulmonary artery. The occurrence of the acute embolism was promptly detected and the removal of tumor was performed under cardiopulmonary bypass. The patient made good postoperative progress.

Acute Disease↗

PubMed1997

Trunk rotation monitor using angular velocity sensors.

To monitor the low back risk imposed by asymmetric postures at workplaces, a method using angular velocity sensors was studied. According to a simple model analysis, trunk rotation could be calculated from the angular velocities measured at both the waist and shoulder and from the inclination of each angular velocity sensor. We thus developed a new detector consisting of an angular velocity sensor (ENC-05D, Murata, Japan) for detecting angular velocity and an acceleration sensor (ADXL05, Analog Devices, USA) for measuring inclination. The precision of the angular velocity sensor was high as the correlation coefficient between the output of the sensor and the true value was 0.9996. When the detectors were affixed to a subject and compared with data measured by a Vicon System 370 (Oxford Metrics, UK), the correlation coefficients between the two methods were 0.949 and 0.815 during model tasks of box transfer and box lifting, respectively. In a model of lifting boxes at different rates, the mean and standard deviation increased according to the task speed. This method was shown to be of practical use for monitoring trunk rotation.

Biomechanical Phenomena↗

PubMed1997

Swell-preventing effect of intermittent exercise on lower leg during standing work.

This study investigated the effectiveness of several possible exercises for performance during standing work in order to prevent lower leg swelling and relieve subjective complaints. Volume changes in the lower leg were measured using bioelectrical impedance plethysmography in 13 healthy male subjects aged 23-36 years. Subjective complaints of leg pain, leg dullness and whole body fatigue were also recorded. Measurements were performed at two-minute intervals during a one-hour period of standing with insertions of one-minute of exercise every 10 min. The exercises were knee-bending, foot-stepping, walking, and heel-raising. The change rates of impedance over one hour were 2.2%, 4.0%, 4.6%, and 6.3%, respectively, indicating that leg volume was increased under all exercise conditions. Among exercises, the swell-preventing effect of knee-bending was strongest, and that of heel-raising was weakest. Heel-raising also yielded the highest number of subjective complaints. Knee-bending, which uses the thigh and calf muscles simultaneously, was considered the most effective for suppressing lower-leg swelling and minimizing subjective complaints.

Adult↗

PubMed1997

[Replacement of the aortic root with woven and knitted Dacron composite graft].

Some of the patients with annuloaortic ectasia or Stanford type A require aortic root replacement. If conventional Bentall procedure is employed in such cases, aortic root will become a cylindrical shape totally lacking sinus of Valsalva because the procedure utilizes a straight tube. The sinuses of Valsalva support an important role in opening and closing the valvar leaflets, and opening of the coronary arteries, together with the interleaflet triangles and the sinutubular junction. In this study, we performed aortic root replacement with composite graft which consisted of two types of graft including 30 mm Knitted Dacron Graft (Gelsoft) with different dilation rates and 30 mm Woven Dacron Graft (Hemashield) as well as bioprosthesis (27 mm Carpentier-Edwards), in order to reconstruct sinus of Valsalva. Post-operative angiography revealed an excellent diastolic coronary flow, as evidenced by proximal Knitted graft of 37 mm in diameter, distal Woven graft of 30.3 mm in diameter and Doppler flow DSVR (Diastolic/Systolic Velocity Ration) of 2.2 measured at the left coronary orifice. Since it is difficult to obtain homograft at present, this procedure would be worth trying during aortic root replacement.

Aged↗

PubMed1996

Vasospastic angina in a patient with Fabry's disease who showed normal coronary angiographic findings.

It has been reported that coronary diseases in patients with Fabry's disease are induced by deposits in endothelial cells and coronary smooth muscle cells. Most of those are ischemia due to stenosis. This report describes a case of patient with Fabry's disease who showed severe vasospasms without coronary artery stenosis during acetylcholine loaded coronary angiography. In this case, a myocardial biopsy revealed that the deposits in the endothelial cells of the myocardial capillaries were lamellated appearance. Recently, it is reported that endothelial cell damage could be an important cause of coronary vasospasm. This case suggests that the some sort of functional disorder was induced by glyco-sphingolipid deposits in the coronary endothelial cells, and that this might have led to coronary artery spasms without the organic stenosis of coronary arteries.

Adult↗

PubMed1996

[Analysis of participation rates of atomic bomb survivors in health examinations].

Participation rates of atomic bomb survivors in health examinations were analyzed with a multiple logistic regression model. Rates were obtained for each stratum by sex, age group and residential ward. The effect of residential wards was considered in relation to the social indices of the wards. The effects of sex, age group and residential ward on participation rates were as follows: (1) Females had higher participation rates than males in the working age group (40-64). No sex differences were seen after age 65. (2) The participation rates had a peak around age 70 and were exceptionally high also in the youngest age group (40-44). (3) Participation rates were higher in suburban wards than in central wards. The participation rates had a negative correlation with urban characteristics while they had a positive correlation with suburban characteristics. In particular they had significant negative correlation to the number of clinics and positive correlation with voter participation rates in elections. These results suggest the need for a new type of urban health examination and reflection of the general attitude of the residents to the government.

Adult↗

PubMed1995

Load on the low back of teachers in nursery schools.

In order to evaluate the load on the low back of teachers in nursery schools, basic activity, working posture, child-lifting, and desk-lifting were analyzed for eight nursery teachers using video recording. The trunk inclination angle (TIA) was also measured continuously during full workshifts for 20 nursery teachers using an inclination monitor. The nursery teachers in the 0-1 (year) age class more often adopted low working postures, "sitting on the floor" and "kneeling," while teachers in the 4-5 age class more frequently adopted high working postures, "standing" and "sitting on a chair." The mean of TIA among all subjects was 20 degrees. The time spent at a TIA of more than 20 degrees represented 43% of the workshift. The mean and time distribution of TIA did not differ between the age classes. The frequency of trunk-lifting from severe bending forward (TIA > 45 degrees) was 86 times/hour on average. The frequency of trunk-lifting was highest in the 0-1 age class. The number of times of child-lifting was 46 in the 0-1 age class, while it was 1 in the 4-5 age class.

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