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Biomedical subjects

H S Song

Publications and source records attributed to H S Song.

35 records · Page 2Linked to original sources
PubMed1997

Epidural morphine plus ketamine for upper abdominal surgery: improved analgesia from preincisional versus postincisional administration.

Increased postoperative pain may be caused by central nervous system plasticity, which may be related to actions of N-methyl-D-aspartic acid (NMDA) receptors on neurons in the dorsal horn of the spinal cord. Opioids act mainly on presynaptic receptors and reduce neurotransmitter release, while ketamine antagonizes NMDA receptors and prevents wind-up and long-term potentiation. Thus, we postulated that central nervous system sensitization would be prevented more effectively by the preoperative use of these two drugs simultaneously, and the effect of preemptive analgesia would be demonstrated. Ketamine, 60 mg, and morphine, 2 mg, were injected epidurally through an indwelling catheter that was inserted at the T7-8 interspace in 60 ASA physical status class 1-2 patients. The drugs were injected before induction of anesthesia (Group 1; n = 30) or immediately after removal of a surgical specimen (Group 2; n = 30). An additional 2 mg of morphine was injected when the patients complained of resting pain. The analgesic effect was assessed by the time from first analgesic injection to second dose and the number of patients who needed supplemental injections. Complications were also noted. The duration of analgesia was longer (P < 0.01) in Group 1 (31.1 +/- 16.0 h) than in Group 2 (21.1 +/- 12.0 h), and the proportion of patients who needed supplemental injections was decreased (P < 0.05) in Group 1 (56.7%) compared with Group 2 (90.0%). The incidence of adverse effects was not different between the two groups. In conclusion, preoperative administration of morphine and ketamine is more effective in reducing postoperative pain than it is when given during the operation.

Abdominal Pain↗
PubMed1997

Propofol attenuates ischemia-reperfusion injury in the isolated rat heart.

UNLABELLED: The purpose of this study was to examine the direct effects of propofol on ischemia-reperfusion injury using an isolated Langendorff rat heart preparation. Hearts were perfused with Krebs-Henseleit (K-H) solution (control); intralipid; or 10, 30, and 100 microM propofol. Hearts were rendered globally ischemic for 25 min, then reperfusion was begun with K-H solution for 30 min. Treatment with 100 microM propofol delayed the onset of contracture during ischemia compared with control or intralipid treatments (6.4 +/- 2.1 vs 4.4 +/- 1.4 or 4.1 +/- 0.7 min, respectively; P < 0.05). During reperfusion, 100 microM propofol increased coronary flow and reduced lactate dehydrogenase release compared with control or intralipid treatments. After 30 min of reperfusion, left ventricular developed pressure (LVDP) returned to 55 and 76 mm Hg in the 30 and 100 microM propofol-treated groups, respectively, whereas LVDP was 39 mm Hg in the control group. The hearts treated with 100 microM propofol showed significantly lower left ventricular end-diastolic pressure compared with the control or intralipid groups 30 min after reperfusion (29 +/- 13 vs 48 +/- 5 or 48 +/- 11 mm Hg, respectively; P < 0.05). In histological evaluation, control and intralipid hearts had increased injury severity scores compared with hearts treated with 100 microM propofol (1.8 +/- 0.9 and 1.7 +/- 0.8 vs 1.0 +/- 0.7, respectively; P < 0.05). In conclusion, we suggest that propofol administered before and during global myocardial ischemia has cardioprotective effects on ischemia-reperfusion injury. IMPLICATIONS: It is important to protect the heart from injury by ischemia and reperfusion. The current study demonstrates that in the isolated rat heart, propofol attenuates mechanical, biochemical, and histological changes causes by ischemia and reperfusion.

Anesthetics, Intravenous↗
PubMed1997

Blockade of myocardial ATP-sensitive potassium channels by ketamine.

BACKGROUND: The adenosine triphosphate (ATP)-sensitive potassium (KATP) channel underlies the increase in potassium permeability during hypoxia and ischemia. The increased outward potassium current during ischemia may be an endogenous cardioprotective mechanism. This study was designed to determine the effects of ketamine on KATP channel in rat hearts. METHODS: Inside-out and cell-attached configurations of patch-clamp techniques and 3 M potassium chloride-filled conventional microelectrodes were used to investigate the effect of ketamine on KATP channel currents in single rat ventricular myocytes and on the action potential duration of rat papillary muscles, respectively. RESULTS: Ketamine inhibited KATP channel activity in rat ventricular myocytes in a concentration-dependent manner. In the inside-out patches, the concentration of ketamine for half-maximal inhibition and the Hill coefficient were 62.9 microM and 0.54, respectively. In a concentration-dependent manner, ketamine inhibited pinacidil- and 2,4-dinitrophenol-activated KATP channels in cell-attached patches. The application of ketamine to the intracellular side of membrane patches did not affect the conduction of single-channel currents of KATP channels. Ketamine increased the action potential duration, which was then shortened by pinacidil in a concentration-dependent manner. CONCLUSIONS: Ketamine inhibited KATP channel activity in a concentration-dependent manner. These results suggest that ketamine may attenuate the cardioprotective effects of the KATP channel during ischemia and reperfusion in the rat myocardium.

Adenosine Triphosphate↗
PubMed1997

Masseter muscle atrophy after ostectomy of the mandibular angle in rabbits.

In order to get information about changes in the masseter muscle when operations are performed on the mandibular angle area, we classified 70 New Zealand White rabbits into group O (ostectomy) and group D (dissection). In group O we performed unilateral ostectomy of the mandibular angle, while in group D we performed unilateral dissection of the masseter muscle limited to the mandibular angle area. Then we compared morphologic, histologic, and histochemical changes in experimental masseter muscles with those in normal control masseter muscles. We examined 5 rabbits in each group at the following intervals: 1, 2, 4, 6, 8, 12, and 24 weeks. In group D (dissection), there were no remarkable changes at all examinations. In group O (ostectomy), there was a 30 percent decrease in experimental muscle mass compared with control muscle. On examination of muscle fiber types, a decrease in type I fibers and an increase in type IIA and IIB fibers were noticed (p < 0.05). Each experimental muscle fiber became more irregularly and angularly shaped, and mean fiber area also was reduced. Sarcomere lengths of experimental muscle fibers were significantly reduced to 80 percent of control values (p < 0.05) during the first 4 weeks, but after 6 weeks they were lengthened to control values. Collagen and fibrin did not show much difference between experimental and control muscles. All these findings imply that masseter muscle atrophy after ostectomy of the mandibular angle is not due to connective-tissue changes but to individual muscle fiber atrophy accompanied by functional adaptation of sarcomeres and changes in muscle fiber types.

Adaptation, Physiological↗
PubMed1996

Induction chemotherapy with idarubicin plus N4-behenoyl-1-beta-D-arabinofuranosylcytosine in acute myelogenous leukemia: a newly designed induction regimen--a prospective, cooperative multicenter study.

This report describes the results of induction chemotherapy with idarubicin (IDA) plus N4-behenoyl-1-beta-D-arabinofuranosylcytosine (BH-AC), a newly designed induction regimen, in cases of previously untreated acute myelogenous leukemia (AML). The study was conducted by the Multicenter Clinical Study Group of the Korean Biologic Response Modifier Society (KBRMS). From March 1994 through January 1995, 40 patients were treated. The median age was 30 years (range, 15 months to 65 years), with a distribution according to the French-American-British (FAB) classification of one MO, nine MI, 15 M2, six M3, four M4, and five M5 patients. Remission induction therapy consisted of IDA 12 mg/m2 intravenously (i.v.) over 30 minutes daily on days 1 to 3, in combination with BH-AC 300 mg/m2 over 4 hours daily on days 1 to 7 (in patients aged 41 to 65 years, BH-AC dosage was decreased to 200 mg/m2/d). Complete remission (CR) was achieved in 30 patients (75%), 22 by the first induction therapy and eight by the second induction therapy. Ten patients (25%) failed to respond to therapy, six due to resistant disease and four due to death caused by aplasia. The time to CR was 30 days, the median granulocytopenic period was 19 days, and the thrombocytopenic period was 24 days. All nonhematologic side effects such as nausea, vomiting, mucositis, skin eruption, liver and cardiac dysfunction, and neurotoxicity, were transient and tolerable. These data indicate an efficacy comparable to that of other combinations of IDA (or other anthracyclines) with cytosine arabinoside (Ara-C) for remission induction in AML.

Adolescent↗
PubMed1996

Neglect of childhood strabismus: Keelung Ann-Lo Community ocular survey 1993-1995.

Strabismus is a major cause of amblyopia. Parents not aware of the adverse outcome of untreated strabismus is thought to be a major reason of their affected child not being discovered earlier. An ocular survey was therefore conducted to examine the relative neglect of strabismus by the public, using myopia as a reference eye disorder. Specific objectives included estimating the prevalence of these ocular diseases, comparing the self-reported rate to the test-based rate, and investigating how much parents knew about these ocular diseases. Between 1993 and 1995, 862 elementary students in the first, third, and sixth grade at Keelung Ann-Lo Community were screened. The prevalence of manifest strabismus was 1.62% (95% CI = 1.19% approximately 2.05%). Of those with strabismus, three (21.4%) knew that they had strabismus. Neither the prevalence nor the self-known proportion of strabismus changed substantially with school grade, suggesting that the majority of strabismus afflicted children remain unrecognized during their elementary school years. The amblyopia proportion in those with tropia was 42.9% and reduced to 21.5% after abnormal refractive error was excluded. Of six knowledge statements about each ocular disorder, parents answered 2.13 (SD = 1.40) strabismus statements correctly, which was significantly less than their response on myopia statements (4.32 with SD = 1.24) (p < .0001). Onset age of strabismus was the question answered least correctly, implying that parents are not aware of the timing of treating strabismus. Our findings suggest that childhood strabismus was neglected by the public before the implementation of National Health Insurance (NHI). Should a similar study continued to be conducted in the future, the efficacy of NHI in the early recognition and treatment on childhood strabismus can be evaluated.

Child↗
PubMed1995

Clinical application of simultaneous pattern VEP and pattern ERG recording.

Thirteen eyes of optic neuropathy and 13 eyes of maculopathy during Sep. 1990-May 1992 were studied by simultaneous pattern VEP (PVEP) and pattern ERG (PERG) recording. In optic neuropathy, the P100 of PVEP was delayed in 7 eyes (ave. 108.87 msec; normal 94.41 +/- 3.51 msec), absent in 5 eyes, normal in 1 eye. Their PERG showed normal P50 amplitude (either normal or delayed latency) but small or absent N95 in 8 eyes. In maculopathy, the P100 of PVEP was delayed in 2 eyes (ave. 103.59msec), absent in 7 eyes, normal in 4 eyes. However, their PERG showed 12 eyes had small or absent P50. Combined PVEP & PERG test, when compared to PVEP alone, increased the diagnostic value from 57.1% to 100% for optic neuropathy and from 42.9% to 80% for maculopathy in this study. Thus, simultaneous PVEP & PERG recording is highly recommended in evaluation of anterior visual pathway disorders.

Diagnosis, Differential↗
PubMed1993

Comparison of the effects of the laryngeal mask airway and endotracheal intubation on vocal function.

We have compared changes in vocal function produced after insertion of a laryngeal mask airway (LMA) with those produced by tracheal intubation in 20 patients. Using acoustic waveform analysis, we computed amplitude variability (AV), pitch variability (PV), harmonics-to-noise ratio (HNR) and additive noise level (ANL) before anaesthesia and at 1, 4, and 24 h after tracheal extubation. There were no significant changes in vocal function after extubation except for HNR ratio (P = 0.046) at 4 h in the LMA group. There were differences in all four variables at 1 h, 4 h, or both, after tracheal extubation compared with baseline in the tracheal tube group. In both groups, all variables were the same as baseline values 24 h after extubation. We observed significant differences in AV (4 h), PV and ANL (1, 4 h) values between the two groups. These observations suggest that the LMA causes less vocal change than tracheal intubation.

Adult↗
PubMed1992

The pattern visual evoked potential and pattern electroretinogram in drusen-associated optic neuropathy.

Sixteen patients (29 eyes) with optic disc drusen were studied prospectively for clinical and electrophysiologic evidence of impaired optic nerve conduction. Abnormalities were detected in the following areas: visual acuity, eight (28%) of 29 eyes; kinetic visual field, 22 (76%) of 29 eyes; results of Farnsworth-Munsell 100-Hue test, 12 (41%) of 29 eyes; and flash visual evoked potential, 13 (54%) of 24 eyes. Simultaneous pattern visual evoked potentials and results of pattern electroretinograms were recorded. The P100 latency of the pattern visual evoked potential was prolonged in 41% of eyes. The P50 and N95 components of the pattern electroretinogram were also analyzed. The P50 amplitude was reduced in only four (17%) of 24 eyes. The most common abnormality was a reduction in amplitude or the absence of the N95 component in 19 (79%) of 24 eyes, reflecting ganglion cell dysfunction. The data support mounting evidence that the P50 and N95 components of the pattern electroretinogram have different retinal origins.

Adolescent↗
PubMed1992

Disappearance of Kayser-Fleischer rings following liver transplantation.

1. Four cases of Kayser-Fleischer rings of Wilson's disease were observed to disappear after liver transplantation. 2. The disappearance of Kayser-Fleischer rings was in reverse order from that in which they appear. 3. The duration of disappearance was variable. 4. The density of Kayser-Fleischer rings correlated with the duration of clinical symptoms.

Adolescent↗
PubMed1991

Uhthoff's symptom in optic neuritis: relationship to magnetic resonance imaging and development of multiple sclerosis.

Eighty-one patients with a first attack of isolated optic neuritis, 40 with Uhthoff's symptom (Group 1) and 41 without (Group 2), were studied. All had a neurovisual examination, 74 of 81 patients had the pattern visual evoked potential recorded at rest, and 43 had magnetic resonance imaging brain scans. The pattern visual evoked potential P100 latency was prolonged, Group 1 with a mean of 136 +/- 19 msec. Group 2 with a mean of 131 +/- 19 msec (control subjects, 102 +/- 5 msec; n = 84), and the P100 amplitude was reduced, without significant difference between the groups. Abnormal magnetic resonance imaging scans were present in significantly more patients in Group 1 (p less than 0.025). Treatment of optic neuritis with corticosteroids had no effect on the evolution or duration of Uhthoff's symptom. Overall, 35 of 81 (43%) patients, followed for a mean of 3.5 years, developed multiple sclerosis. The incidence was significantly greater in Group 1 (p less than 0.01). Uhthoff's symptom also correlated with a higher incidence of recurrent optic neuritis. We conclude that Uhthoff's symptom is a prognostic indicator for the early development of multiple sclerosis.

Acute Disease↗
PubMed1991

Bee sting optic neuritis. A case report with visual evoked potentials.

Simultaneous recordings of the pattern visual evoked potential and the pattern electroretinogram were recorded in a case of unilateral optic neuritis following a bee sting on the eye. The patient presented with severe eye pain, apoplectic visual loss, acute optic disc swelling and minimal signs of ocular inflammation and eyelid edema. The vision failed to recover. The electrophysiological recordings initially showed a delay in the P100 wave of the pattern visual evoked potential. On follow-up, a normal latency and amplitude of the P50 wave of the pattern electroretinogram was recorded with the flattening of the N95 component, but the pattern visual evoked potential was absent. The data suggests that the optic nerve was demyelinated acutely, and that subsequently axonal loss and degeneration of retinal ganglion cells occurred.

Adult↗
PubMed1989

Scoliosis induced by anterior and posterior rhizotomy.

This paper presents the result and statistical analysis of an experiment in which selective anterior or posterior rhizotomy was carried out under microscopic surgery. The animals used for the experiment were 48 young rabbits, and they were divided into four groups. Group 1, which was used as control, was subjected to lower dorsal bilateral laminectomies with dural incision; Group II to laminectomies with three right posterior rhizotomies; Group III to laminectomies with three right anterior rhizotomies, and Group IV to laminectomies with three right anterior and posterior rhizotomies. Scoliosis was induced in Groups II, III, and IV. There was no significant statistical difference in the degree of curvatures among these three groups. The convexity of the curvature faced to the side of the divided roots. In Groups III and IV, scoliotic curvatures were obvious within 2 weeks, but there were no considerable changes thereafter. In Group II, the curves progressed slowly up to the 12th week. They were statistically significant at the fourth week and increased continuously thereafter. The histologic findings in Groups III and IV showed denervation atrophy of the paravertebral muscles at the apex of the curvature, but there was little or no muscle atrophy in Groups I and II. The experimental results indicate that scoliosis may be induced not only by anterior root paralysis but also by selective posterior root paralysis.

Animals↗
PubMed1987

Renal and renin effects of sodium thiopental in rabbits.

Unilateral renal arterial infusion of sodium thiopental on renal function and renin secretion were investigated in unanesthetized rabbits. Sodium thiopental infusion in doses of less than 0.3 mg/kg/min into unilateral renal artery caused dose-dependent increases in urine flow, urinary excretion of electrolytes, fractional excretion of sodium and free water clearance with no changes in systemic blood pressure and clearance of p-aminohippuric acid (renal blood flow). An anesthetic dose of sodium thiopental administered intravenously caused decreases in systemic blood pressure, renal hemodynamics, urine flow and free water clearance during the early period of anesthesia followed by increases in urinary excretion of sodium and fractional excretion of sodium. Unilateral renal arterial infusion of sodium thiopental decreased the renin secretion rate and plasma norepinephrine concentration in renal vein, whereas an anesthetic dose of sodium thiopental administered intravenously increased the renin secretion rate. These observations suggest that the diuretic, natriuretic and renin suppressive effects of sodium thiopental may be due to an inhibition of intrarenal sympathetic nervous system or due to a direct tubular action.

Animals↗
PubMedDate not supplied

Unfavorable results and their resolution in mandibular contouring surgery.

Since the development of mandibular contouring surgery, there have been many unfavorable results due to technical reasons. Those results include asymmetry, undercorrection, overcorrection, and an incorrect contour line. Over three years the authors have analyzed 19 cases of unfavorable results and found the following: (1) There have been 7 cases of undercorrection, 5 cases of asymmetry, 5 cases of incorrect contour line, and 2 cases of overcorrection. (2) The main technical errors that cause unfavorable results seem to be the simple straight cutting of mandible angles instead of curved cutting using multistaged curved ostectomy. (3) We suggest that the basic way to prevent unfavorable results in mandibular contouring surgery is to contour the mandible, including angle, body, and symphysis, as a whole by way of multistaged curved ostectomy.

Adult↗