Biomedical subjects

Y J Lim

Publications and source records attributed to Y J Lim.

61 records · Page 4Linked to original sources

PubMed1985

[Effect of calcium antagonist (diltiazem) on left ventricular diastolic properties in essential hypertension: a pulsed Doppler echocardiographic study].

To evaluate the acute effect of diltiazem on left ventricular diastolic properties, we measured transmitral flow in 15 patients with essential hypertension using pulsed Doppler techniques. Before administering diltiazem, the peak velocity (R) and the deceleration rate of rapid inflow decreased significantly as compared with healthy subjects, but the peak velocity during atrial contraction (A) and the A/R increased significantly. Immediately after the intravenous administration of 10 mg diltiazem, blood pressure decreased from 157 +/- 22/96 +/- 12 mmHg to 135 +/- 19/82 +/- 11 mmHg (p less than 0.001) and the heart rate increased from 69 +/- 10/min to 74 +/- 10/min (p less than 0.05). However, 30 minutes after the injection, these returned to control values. The peak velocity and deceleration rate of rapid inflow were 52 +/- 9 cm/sec and 227 +/- 65 cm/sec2, respectively, before administering diltiazem, and five minutes after injection, these parameters increased to 63 +/- 13 cm/sec (p less than 0.001) and 292 +/- 82 cm/sec2 (p less than 0.001), respectively. Thirty minutes later, these values leveled off at 58 +/- 12 cm/sec (p less than 0.01) and 257 +/- 76 cm/sec2 (p less than 0.05), respectively. The peak velocity during atrial contraction was 67 +/- 12 cm/sec before administration, and this did not change significantly after injecting diltiazem. Significant increases in peak velocity and deceleration rate of rapid inflow and decreases in the A/R continued after the blood pressure and heart rate returned to control values. It was therefore concluded that diltiazem improves impaired early diastolic left ventricular filling in essential hypertension.

Adult↗

PubMedDate not supplied

Diagnostic performance of myocardial contrast echocardiography for detection of stunned myocardium.

Improvement in regional wall motion after acute myocardial infarction has been described up to 2 to 3 weeks after the acute event despite restoration of blood flow by early successful reperfusion therapy. The prospective identification of potentially reversible ventricular dysfunction caused by stunned myocardium has significant clinical implications. Twenty-seven patients with acute myocardial infarction underwent myocardial contrast echocardiography (MCE) before, immediately after, and 4 weeks after successful reperfusion therapy. MCE was performed by imaging a parasternal short-axis view during intracoronary arterial injection of 2 ml sonicated ioxaglate (Hexabrix-320). The contrast defect area and contrast-filled area before reperfusion were defined as the risk area and noninfarct area, respectively. The normalized gray level was defined as the ratio of the gray level in the risk area/gray level in the noninfarct area. In 21 patients, wall motion was akinetic or dyskinetic immediately after reperfusion, and 10 of 21 patients in whom wall motion recovered during the chronic stage were defined as patients with stunned myocardium. In patients who showed asynergic wall motion immediately after reperfusion, MCE predicted the recovery of left ventricular wall motion (stunned myocardium) during the chronic stage with a sensitivity of 77%, specificity of 100%, and predictive accuracy of 86%, when a normalized gray level of more than 0.4 was presumed to predict stunned myocardium. We conclude that MCE provided the prospective identification of potentially reversible ventricular dysfunction caused by stunned myocardium, and wall motion in the area of nonenhanced myocardium on MCE immediately after reperfusion is not expected to show reversible dysfunction.

Adult↗

PubMedDate not supplied

Efficacy of prophylactic ondansetron in a patient-controlled analgesia environment.

We conducted a prospective, randomized, double-blind, placebo-controlled trial to examine the efficacy of prophylactic ondansetron on post-operative nausea and vomiting (PONV) during opioid patient-controlled analgesia (PCA). In total, 374 patients using opioid PCA, but otherwise considered to be low risk for PONV, were randomly allocated to ondansetron (4 mg given intravenously and 16 mg added into the PCA pump) or saline (control group). PONV was evaluated in terms of nausea graded on a visual analogue scale, and the number of patients who experienced emetic episodes or needed rescue anti-emetics in the 48-h post-operative period. Patient satisfaction for PCA was scored at the end of the evaluation period. The only difference between the two groups was the higher number of headaches in the ondansetron group. In patients using opioid PCA, but with no other high risk factors for PONV, prophylactic ondansetron does not have any clinical benefit.

Aged↗

PubMedDate not supplied

Comparison between high and low molecular weight hyaluronates in knee osteoarthritis patients: open-label, randomized, multicentre clinical trial.

Efficacy and safety of high and low molecular weight hyaluronates in knee osteoarthritis patients were compared in a randomized, open-label trial. Patients in the high molecular weight hyaluronate group were treated once weekly for 3 weeks and in the low molecular weight group once weekly for 5 weeks. We evaluated weight-bearing pain, degree of flexion, swelling and knee tenderness; frequency and amount of rescue medication; patient and investigator global assessment of pain, and safety over 12 weeks after final injection of study medication. Significant improvements in pain and WOMAC-Likert scores were observed in both groups, but not between groups. Knee joint pain improvement was noted in both groups by patients and investigators during follow-up. Close correlation was observed between patient- and investigator-reported data. There was no significant difference in side-effects between the groups. In conclusion, the efficacy and safety of high and low molecular weight hyaluronate are similar.

Adjuvants, Immunologic↗

PubMedDate not supplied

Efficacy of pulsed electromagnetic therapy for chronic lower back pain: a randomized, double-blind, placebo-controlled study.

This randomized, double-blind, placebo-controlled clinical trial studied the effectiveness of pulsed electromagnetic therapy (PEMT) in patients with chronic lower back pain. Active PEMT (n = 17) or placebo treatment (n = 19) was performed three times a week for 3 weeks. Patients were assessed using a numerical rating scale (NRS) and revised Oswestry disability scores for 4 weeks after therapy. PEMT produced significant pain reduction throughout the observation period compared with baseline values. The percentage change in the NRS score from baseline was significantly greater in the PEMT group than the placebo group at all three time-points measured. The mean revised Oswestry disability percentage after 4 weeks was significantly improved from the baseline value in the PEMT group, whereas there were no significant differences in the placebo group. In conclusion, PEMT reduced pain and disability and appears to be a potentially useful therapeutic tool for the conservative management of chronic lower back pain.

Aged↗

PubMedDate not supplied

Subendocardial myocardial ischemia as assessed with myocardial contrast echocardiography in patients with ischemic heart diseases.

Myocardial contrast echocardiography was used to characterize changes in the regional and transmural myocardial blood flow distribution that were provoked by rapid atrial pacing stress in patients with coronary artery diseases. In patients with coronary organic stenosis, a decrease in the myocardial contrast-enhancement in the subendocardial half after rapid atrial pacing was associated with stress-induced chest pain and electrocardiographic ST-T changes. The decrease in the myocardial contrast-enhancement in the subendocardial half after rapid atrial pacing was not observed in patients without coronary stenosis or after coronary angioplasty. Thus, the finding was considered to reflect myocardial ischemia. Pacing-induced decreases in myocardial contrast-enhancement were observed in some patients with old myocardial infarction and significant resting coronary collaterals. In these patients, myocardial ischemia was considered to have developed at rapid pacing because collateral function was good enough to perfuse the infarct myocardium at rest, but was not good enough to prevent myocardial ischemia at stress. Thus, myocardial contrast echocardiography seems to be particularly useful in assessing myocardial ischemia at stress due to coronary stenosis in patients with angina pectoris and due to poor dynamic collateral function in patients with old myocardial infarction.

Angioplasty↗

PubMedDate not supplied

Surface characterizations of variously treated titanium materials.

The attachment of cells to titanium surfaces is an important phenomenon in the area of clinical implant dentistry. A major consideration in designing implants has been to produce surfaces that promote desirable responses in the cells and tissues. To achieve these requirements, the titanium implant surface can be modified in various ways. This research was designed to elucidate the relationship between surface roughness (Ra) and contact angle (theta) of various engineered titanium surfaces of commercially pure titanium, titanium-aluminum-vanadium alloy (Ti-6Al-4V), and titanium-nickel (TiNi) alloy. The contact angle was measured using distilled water, 1% sodium chloride solution, human neutrophils, and osteoblast-like cells. Surface oxide crystallography was identified by transmission electron diffraction. It was found that: (1) there were no significant differences in contact angles among the 4 media; (2) for commercially pure titanium, a combined treatment (hydrofluoric acid/nitric acid/water --> sodium hydroxide --> oxidation) showed the lowest theta (10.51 degrees in water), while the surface treated with sulfuric acid showed the highest value (72.99 degrees in water); (3) for all commercially pure titanium samples, when theta is greater than 45 degrees, the contact angle increases linearly with Ra (hydrophobic nature) and the surface is covered with rutile-type oxide only, while the contact angle decreases linearly with Ra when theta is less than 45 degrees (hydrophilic nature) and the surface is covered with a mixture of rutile and anatase oxides; and (4) a similar trend was found on Ti-6Al-4V and TiNi surfaces.

Acid Etching, Dental↗