Biomedical subjects

Y C Hwang

Publications and source records attributed to Y C Hwang.

At least 19 recordsLinked to original sources

PubMed2001

Protection of ischemic hearts by high glucose is mediated, in part, by GLUT-4.

Metabolic interventions that promote glucose use during ischemia have been shown to protect ischemic myocardium and improve functional recovery on reperfusion. We evaluated whether the cardioprotection afforded by high glucose during low-flow ischemia is associated with changes in the sarcolemmal content of glucose transporters, specifically GLUT-4. Isolated rat hearts were paced at 300 beats/min and perfused under normal glucose (5 mM) or high glucose (10 mM) conditions in buffer containing 0.4 mM albumin, 0.4 mM palmitate, and 70 mU/l insulin and subjected to 50 min of low-flow ischemia and 60 min of reperfusion. To determine the importance of insulin-sensitive glucose transporters in mediating cardioprotection, a separate group of hearts were perfused in the presence of cytochalasin B (10 microM), a preferential inhibitor of insulin-sensitive glucose transporters. Ischemic contracture during low-flow ischemia and creatine kinase release on reperfusion was decreased, and the percent recovery of left ventricular function with reperfusion was enhanced in hearts perfused with high glucose (P < 0.03). Hearts perfused with high glucose exhibited increased GLUT-4 protein expression in the sarcolemmal membrane compared with control hearts under baseline conditions, and these changes were additive with low-flow ischemia. In addition, high glucose did not affect the baseline distribution of sarcolemmal GLUT-1 and blunted any changes with low-flow ischemia. These salutary effects were abolished when glucose transporters are blocked with cytochalasin B. These data demonstrate that protection of ischemic myocardium by high glucose is associated with increased sarcolemmal content of the insulin-sensitive GLUT-4 and suggest a target for the protection of jeopardized myocardium.

Animals↗

PubMed2001

Clinical course of patients with IgA nephropathy between combined treatment of immunosuppressive agents and ACE inhibitor and ACE inhibitor alone.

BACKGROUND: It has not been clear whether immunosuppressive therapy favorably influences renal function and proteinuria in IgA nephropathy (IgAN). Angiotensin converting enzyme inhibitor (ACEi) has an anti-proteinuric effect in IgAN. A retrospective study was done to see whether the addition of immunosuppressive therapy to ACEi produces a more excellent anti-proteinuric effect and preserves better renal function than ACEi alone. METHODS: A total of 49 patients with proteinuria > 1.0 g/day and serum creatinine concentrations < 1.5 mg/dL were followed-up from at least 1 year to 9 years. Among them, 25 patients were treated with the combination of cyclophosphamide, prednisolone and ACEi while the other 24 were treated with ACEi alone. RESULTS: The combination therapy or ACEi alone both reduced proteinuria with significant value (the combination group: from 5.74 +/- 5.08 to 2.29 +/- 2.77 g/day, ACEi group: from 3.85 +/- 2.54 to 1.68 +/- 1.91 g/day), while no significant differences in reduction of proteinuria were noticed between the two groups. There was no significant elevation of serum creatinine in both groups during follow-up (the combination group: from 0.91 +/- 0.20 to 1.03 +/- 0.38 mg/dL, ACEi group: from 0.93 +/- 0.27 to 0.99 +/- 0.37 mg/dL). This study showed no significant differences in the change in slope of 1/serum creatinine levels during the follow-up period between the two groups. CONCLUSION: We conclude that immunosuppressive therapy may not be beneficial in patients with proteinuric IgAN. ACEi may be a valuable therapeutic agent avoiding serious side effects of immunosuppressive agents.

Adolescent↗

PubMed2000

Amyloid beta -peptide-binding alcohol dehydrogenase is a component of the cellular response to nutritional stress.

Amyloid beta-peptide-binding alcohol dehydrogenase (ABAD) is a member of the family of short chain dehydrogenase/reductases whose distinctive properties include the capacity to bind amyloid beta-peptide and enzymatic activity toward a broad array of substrates including n-isopropanol and beta-estradiol. In view of the wide substrate specificity of ABAD and its high activity on l-beta-hydroxyacyl-CoA derivatives, we asked whether it might also catalyze the oxidation of the ketone body d-3-hydroxybutyrate. This was indeed the case, and oxidation proceeded with K(m) of approximately 4.5 mm and V(max) of approximately 4 nmol/min/mg protein. When placed in medium with d-beta-hydroxybutyrate as the principal energy substrate, COS cells stably transfected to overexpress wild-type ABAD (COS/wtABAD) better maintained 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide reduction, cellular energy charge, and morphologic phenotype compared with COS/vector cells. Using a severe model of metabolic perturbation, transgenic mice with targeted neuronal expression of ABAD subjected to transient middle cerebral artery occlusion showed strokes of smaller volume and lower neurologic deficit scores in parallel with increased brain ATP and decreased lactate, compared with nontransgenic controls. These data suggest that ABAD contributes to the protective response to metabolic stress, especially in the setting of ischemia.

3-Hydroxybutyric Acid↗

PubMed2000

Reduction of UV-induced cell death in the human senescent fibroblasts.

We studied mechanisms by which senescent cells acquire resistance to UV-induced cellular insults. Human primary foreskin fibroblast culture was used since it undergoes cellular senescence in vitro after a limited number of passages. Senescence was induced by a brief treatment of the early passage cells with 100 microM of H2O2 for 1 h, and subsequent culture for 3 weeks. Hydrogen peroxide-treated cells showed an enhancement of senescence-associated beta-galactosidase activity. In the senescent cells, DNA fragmentation in response to UV-irradiation was found to decrease significantly compared with that in the young cells. The SAPK/JNK activation by UV irradiation was reduced in both non-treated senescent cells and the hydrogen peroxide-induced senescent cells, suggesting that a reduced DNA fragmentation by UV-irradiation in the senescent cells is closely related to the decreased SAPK/JNK activity. Since a cell cycle inhibitor, p21Waf1, has been implicated in protecting cells against apoptotic cell death, we determined p21Waf1 to assess whether its elevation has any impact on the reduction of UV-induced activation of SAPK/JNK in the senescent cells. The expression of p21Waf1 increased in both the nontreated and the hydrogen peroxide-treated senescent cells. Our study also revealed that the blockage of SAPK/JNK activation in the senescent cells was closely related to the increased level of p21Waf1. Our observation might provide clues about molecular mechanism of resistance to DNA fragmentation and the consequent cell death by UV-irradiation.

Cell Culture Techniques↗

PubMed2000

Senescence-like changes induced by hydroxyurea in human diploid fibroblasts.

Hydroxyurea was found to inhibit the growth of human diploid fibroblasts, which resulted in senescence-like changes both in morphology and replicative potential similar to the replicative senescence. SA-beta-gal activity, a typical characteristic of the replicative senescence was also induced through a long-term treatment of the presenescent cells with 400-800 microgM of hydroxyurea for about 3 weeks. In addition, we determined the levels of cyclin-dependent kinase inhibitors, p21(Waf1) and p16(INK4a), and the p53 tumor suppressor in order to monitor its effect on cell cycle and stress responses. We observed a great induction of both p53 and p21(Waf1), but not of p16(INK4a) in the premature senescent cells. UV-irradiation of the premature senescent cells showed a decreased level of DNA fragmentation presumably ascribed to the reduced activation of stress-activated protein kinases. These results suggest that a chronic hydroxyurea treatment induces the cellular senescence in association with the induction of p53 and p21(Waf1).

Cells, Cultured↗

PubMed1999

Aging process is accompanied by increase of transglutaminase C.

Crosslinking has been suggested as one of the mechanisms involved in the aging process. Among the various random or enzyme-mediated crosslinking reactions, transglutaminase (TGase)-catalyzed crosslinking activity has been proposed for its possible involvement in cell proliferation, differentiation, carcinogenesis, programmed death, and aging. Moreover, recent findings of TGase C as a putative signal transducer and cell cycle regulator has renewed interest in the study of TGase C in relation to aging phenomena. The ubiquitous presence of TGase C compared to the organ-specific localization of other types of TGases has attracted special attention as a cellular aging device. In the present investigation for in vitro studies, we have compared the pattern of TGase C in young and old human red blood cells, separated by density differentiation, and in early and late-passage or hydrogen peroxide-treated human primary fibroblasts. For in vivo study, we monitored the age-dependent changes of TGase C in the liver and brain tissues of 4, 12, 18, and 24-month-old Sprague-Dawley rats. We obtained evidence that both the activity and protein levels of TGase C were high in old RBC and late-passage or hydrogen peroxide-treated fibroblasts. Similar findings were seen in liver and brain tissue such as age-dependent increases in TGase activity and protein level in an organ-specific pattern. These data suggest that TGase C might play an active role in the cellular process with age.

Adult↗

PubMed1997

Bonding strengths of porcelain repair systems with various surface treatments.

STATEMENT OF PROBLEM: Metal porcelain combined surfaces are often involved in the repairing of fractured porcelain fused to metal restoration. PURPOSE: This study investigated the effect of surface treatments on the bonding strength of porcelain fused to metal prosthesis repair. MATERIAL AND METHODS: Specimens (8 x 4 mm) were fabricated with Biobond II casting alloy and randomly divided into three surface groups: metal, porcelain, and metal-porcelain combined surface. Biobond porcelain system and commercially available porcelain repair systems were tested. The metal surface group was further divided into two subgroups: control and sandblasting treatment (Al2O3, 50 microns, 20 seconds). In the porcelain surface group, there were three subgroups: (1) control, (2) sandblasting, and (3) 9.5% hydrofluoric acid etching for 4 minutes. The metal-porcelain surface combined group was divided into three subgroups: (1) control, (2) sandblasting, and (3) sandblasting and etching. The manufacturer's instructions for repair systems were followed for specimen preparation. Shear bond strengths of 10 specimens for each subgroup were determined with a universal testing machine after storing in distilled water at 37 degrees C for 7 days. The data were analyzed with analysis of variance and Scheffé F-test at the 95% significance level. RESULTS: The Liner-M repair system showed significantly greater strength than the other tested systems on the metal surface with or without sandblasting treatment (p < 0.05). On the porcelain surface, the strengths of sandblasting and etching subgroups ranged from 7.2 to 16.8 MPa, and 6.8 to 16.8 MPa, respectively. There were no significant differences in bond strengths between sandblasting and combined treatment of the metal-porcelain combined surface group (p > 0.05). CONCLUSION: The results of this study suggest that metal substrates treated with sandblasting and porcelain treated with either hydrofluoric acid or sandblasting can increase repair strength.

Dental Bonding↗

PubMed1993

Leiomyosarcoma of the gastric cardia: report of a case with unusual clinical manifestation.

In an uncommon presentation of gastric leiomyosarcoma, a rare malignancy of the stomach, a patient aged 63 years was admitted due to progressive exertional dyspnea. Plain film and computed tomography of the chest showed that this patient had a mediastinal neoplasm and the pulmonary function test revealed compromised pulmonary function. Operative findings revealed that this tumor arose in the esophageal-cardiac junction with mediastinal extension; the pathology report was leiomyosarcoma. The patient recovered well and the pulmonary embarrassement was relieved in the succeeding one-year period.

Cardia↗

PubMed1992

Anatomy and classification of acupoints.

Acupuncture points are conceived as points on the skin reflecting visceral conditions and the sites for acupuncture treatment. In the skin, acupoints tend to show higher electric conductivity and have higher concentration of neural and vascular elements as well as mast cells. Locations of some acupoints correspond to the motor points, others to the Golgi tendon organs. There is a group of midline acupoints. Most acupoints are associated with meridians and are known as meridian points. The nature of meridians is under scientific scrutiny. For identification of canine acupoints, the human meridian nomenclature was adopted.

Acupuncture Points↗

PubMed1992

Acupuncture atlas.

Explore the source record for details and available documents.

Acupuncture Points↗

PubMed1991

Modulation of murine radiation-induced fibrosarcoma-1 tumor metabolism and blood flow in situ via glucose and mannitol administration monitored by 31P and 2H nuclear magnetic resonance spectroscopy.

The hyperglycemia-induced in situ metabolism and blood flow changes produced in s.c. implanted murine radiation-induced fibrosarcoma-1 tumors, grown on the flanks of female C3H/HeJ mice, were examined with 31P and 2H nuclear magnetic resonance. Initial experiments verified a hyperglycemic tumor acidification similar to that reported earlier with a different substrain of mice, C3H/AnF (J.L. Evelhoch et al., Proc. Natl. Acad. Sci. USA, 81: 6496-6500, 1984). Changes in the tumor pH, phosphorus metabolites, and blood flow were then compared after administration of saline, glucose, or mannitol (a nonmetabolizable glucose analogue) using a mole-equivalent dose of the sugars (i.e., 0.8 mmol/20g mouse). Neither saline (n = 8) nor mannitol (n = 6) administration had any marked effect upon tumor pH, whereas glucose administration produced a mean maximum tumor pH reduction of 0.74 +/- 0.09 (SE; n = 9) during the 2.5 h post-glucose injection. No significant changes in high energy phosphate concentrations were observed during the same period after saline injection. After glucose injection, the [phosphocreatine] gradually decreased by 64% (P = 0.0001). After the initial 1 h post-glucose injection, the [inorganic phosphate] increased by 58% (P = 0.0001), and the [nucleoside triphosphates] decreased by 29% (P = 0.0001) during the following 1.5 h. After mannitol injection, while there was no change in [inorganic phosphate] over time (P = 0.37), the [phosphocreatine] decreased by 33% (P = 0.0001) and the [nucleoside triphosphates] decreased by 21% (P = 0.0015) within 20 min, then both the [phosphocreatine] and [nucleoside triphosphates] remained at constant levels during the following 2 h. In parallel experiments, the volumetric rate of tumor blood flow and perfusion was measured by 2H nuclear magnetic resonance monitoring of 2H2O washout kinetics (S-G. Kim and J. J. H. Ackerman, Cancer Res., 48: 3449-3453, 1988); tumor blood flow decreased by 80% (P = 0.0001, n = 11), 60% (P = 0.0031, n = 4), and 20% (P = 0.058, n = 10) at 2 h after glucose, mannitol, or saline injections, respectively. These results suggest that anaerobic glycolysis is a requirement for hyperglycemic tumor acidification. However, the decrease in tumor blood flow accompanying hyperglycemic acidification suggests that flow reduction also may be a contributing or a required cofactor for acidification via inhibition of lactic acid egress.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed1990

[Evaluation of abdominal motor blockade using surface integrated electromyography during bupivacaine spinal anesthesia].

The study was undertaken to investigate abdominal motor blockade and compare sensory-motor differential blockade in bupivacaine spinal anesthesia by surface integrated electromyography (SIEMG). Seventeen physical status I adult male patients underwent lower limb surgery under spinal anesthesia were divided into two groups: hyperbaric bupivacaine (HB) group (n = 8) receiving 3 mL of 0.5% bupivacaine (8% glucose) and isobaric bupivacaine (IB) group (n = 9), 3 mL of 0.5% bupivacaine (glucose-free). Each patient was monitored with a blood pressure cuff, an ECG and a precordial stethoscope. Spinal anesthesia was performed at L3-4 interspace on the lateral position. Immediately following injection of bupivacaine, the patients were turned to the supine position and then simultaneous measurements of sensory blockade using pinprick, abdominal motor blockade at T6, T8, T10, T12 level using SIEMG and lower limb motor blockade using Bromage scale were made for 4 hours. Between two groups, there were no significant differences in terms of age, body weight, height as maximum level and mean times to maximum level of sensory blockade, abdominal motor blockade and lower limb motor blockade. The times of 2-segment regression of sensory blockade were 66.3 +/- 11.1 min in HB group and 115.6 +/- 31.3 min in IB group. The sensory-motor differential blockades were 4.6 +/- 0.5 segments and 4.8 +/- 2.1 segments in HB and IB groups, respectively. According to the linear regression analysis, the correlation between sensory blockade and abdominal motor blockade was better than the lower limb motor blockade and abdominal motor blockade. (Correlation coefficient (r): 0.893 vs 0.580 in HB group; 0.773 vs 0.366 in IB group).(ABSTRACT TRUNCATED AT 250 WORDS)

Abdomen↗

PubMed1988

Effect of acupuncture on young pigs with induced enteropathogenic Escherichia coli diarrhea.

Thirty-four preweaning pigs with induced enteropathogenic Escherichia coli diarrhea were treated with electroacupuncture, traditional acupuncture, or neomycin. In the group treated with electroacupuncture, points GV-1, bilateral ST-36, and Bai-hui were stimulated electrically. In the group treated with traditional acupuncture, points GV-1, bilateral ST-36, BL-20, bulb points, bilateral ear tip, and Shan-gen were used. Acupuncture points CV-12 and bilateral ST-25 also were treated with moxibustion (applying heat generated by a burning herb, Artemisia argyi). Hemoacupuncture also was applied to Shan-gen, bilateral ear tip, and bulb points. Pigs in the third group were given neomycin orally. Five pigs were inoculated with E coli, but were not treated and served as nontreated controls. At postinoculation day 5, 60% of control pigs and greater than 80% of pigs in treated groups recovered from diarrhea. However, at postinoculation day 3, recovery rates for pigs in the control and group treated with electroacupuncture were only 20 and 27.3%, respectively; whereas pigs treated with acupuncture or neomycin attained 81.8 and 71.4% of recovery rates, respectively. Seemingly, traditional acupuncture, but not electroacupuncture, was effective in controlling induced E coli diarrhea in pigs at its early stage.

Acupuncture Therapy↗

PubMed1981

Interfollicular smooth muscle in the skin of the domesticated pig (Sus scrofa).

An interfollicular smooth muscle that spans the triad of hair follicles has been identified in the skin of the domesticated pig (Sus scrofa). This muscle has been previously noted by other investigators and identified as an arrector pili muscle. However, it cannot be interpreted as such for the following reasons: 1) It lies opposite the arrector pili muscle on the follicle; 2) the orientation of its fibers is perpendicular to those of the arrector pili; 3) the two muscles are not continuous; their attachments are different; and 4) contraction of the interfollicular muscle would have little effect on erection of the hairs. Based on structural evidence, it is postulated that upon contraction the muscle draws the base of the three aligned follicles together into a triangular conformation. In so doing, it may rotate the outer two follicles of the triad. Its specific functional role is unknown.

Animals↗

PubMed1981

A preliminary report on an attempt to modify behavior of untamed ponies by acupuncture.

A preliminary study using various acupuncture techniques to modify behavior of untamed ponies was attempted. In five of the seven tested parameters, the animals's behavioral responses were unaffected by acupuncture treatments. However, substantial improvement of general behavior of the nervous ponies was observed in animals treated with jaw and scutiform points. The results are not conclusive and further testing of acupuncture as a mean of modifying animal behavior is desirable.

Acupuncture Therapy↗

PubMed1981

Light microscopic morphology of low resistance skin points in the guinea pig.

This study compares the light microscopic structure of low resistance skin points (LRSP) to high resistance skin points (HRSP) of the guinea pig, Previously, LRSP have been shown to coincide with acupuncture loci. Epidermal nuclei and dermal nuclei were counted at both LRSP and at control points or HRSP. In addition, hair follicles, blood vessels, and sebaceous nuclei were likewise quantitated. This data, collected in a blind manner, was then subjected to statistical analysis using a nested analysis of variance and a Student's "t" test. The former test indicated an increase in density of hair follicles at LRSP, while both demonstrated a decrease in dermal nuclei at LRSP. An interesting finding is that the epidermis at both LRSP and HRSP is indistinguishable at the light microscopic level. This was indicated by both statistical procedures. Finding of a Haarscheibe, an aggregation of Merkel cell-neurite complexes, only at HRSP tends to preclude its role as an acupuncture neurotransducer. Finally, there appeared to be no obvious qualitative differences between LRSP and HRSP observable at the light microscopic level.

Acupuncture Therapy↗

PubMed1980

Experimental studies of effects of acupuncture on enterochromaffin cells: guinea pig enterochromaffin cell count after electro-acupuncture.

Guinea pig acupuncture points located on the back of the animal, cranial and caudal to the last rib in the muscular groove between longissimus dorsi and iliocostalis, were treated by electro-acupuncture (EA). In the duodenum, when compared with the control, the EA-treated group showed a significant decrease of its enterochromaffin (EC) cell count. However, the sham-treated group also had a lower EC cell count compared to the control. Decreased EC counts were also observed in the jejunum and colon in both EA and sham treated groups; however, they were not significant except in the sham-treated colon. The present study demonstrated that in the normal guinea pigs electro-acupuncture on certain points tends to cause a decrease of the EC cell count in some parts of the gut; however, such results cannot be completely attributed to the effect of acupuncture.

Acupuncture Therapy↗

PubMed1978

Two and a half years of acupuncture in Alabama.

From the data presented it appears that acupuncture helped in more than 50% of the patients by either completely or partially controlling pain from certain disorders. Patients helped by acupuncture received 8.55 treatments on the average, while patients not helped by acupuncture only received 4.75 treatments. There is difference between the male and female patients as to the response to acupuncture. However, we noticed that the younger the patient and the shorter the duration of their of problems, the better the response. Patients who had not had surgery to treat the pain syndrome responded better than those who had had previous surgery. Patients with backache who had previously had laminectomy showed better response to acupuncture than patients who had had spinal fusion. It appears that good general health plays an important role in favorable response to acupuncture treatment. Acupuncture may be a valuable extension of a conventional pain clinic and an alternative in patients who are desperate to obtain relief from pain which they failed to obtain from other methods.

Acupuncture Therapy↗