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Biomedical subjects

C H Cheng

Publications and source records attributed to C H Cheng.

At least 37 records · Page 2Linked to original sources
PubMed2001

Effect of isoflurane versus nicardipine on blood flow of lumbar paraspinal muscles during controlled hypotension for spinal surgery.

STUDY DESIGN: This study compared the effects of isoflurane and nicardipine on regional blood flow of the lumbar paraspinal muscles. OBJECTIVES: The purpose of this study was to determine whether treatment with hypotensive agents result in ischemia of the lumbar paraspinal muscles, thereby facilitating surgical procedures. SUMMARY OF BACKGROUND DATA: Despite the general acceptance of controlled hypotension as effective in reducing blood loss during spinal surgery, the changes of blood flow that occur at the lumbar paraspinal muscles when this technique is applied remain unclear. The use of laser Doppler flowmetry allows changes of muscle blood flow to be easily detected in real time with minimal invasion, thereby allowing differences among distinct pharmacological approaches for induction and maintenance of controlled hypotension to be evaluated. METHODS: The prehypotensive and hypotensive (reduction of mean arterial pressure by 20 mm Hg) blood flow of the lumbar paraspinal muscles were assessed with a laser Doppler flowmeter in 40 patients undergoing lumbar spinal surgery. The first half of the patients (n = 20) received isoflurane, whereas the second half received nicardipine to achieve arterial hypotension. RESULTS: Compared with the prehypotensive state, during the hypotensive state, patients in the isoflurane group exhibited a 17% to 46% (mean, 33.7%) decrease in lumbar paraspinal muscle blood flow, whereas patients in the nicardipine group exhibited a 24% to 177% (mean, 82.5%) increase in lumbar paraspinal muscle blood flow. Statistical analysis showed a significant difference in the changes of flux after induced hypotension between the isoflurane and nicardipine group (P < 0.001). CONCLUSIONS: Depending on the pharmacological treatment used to achieve arterial hypotension in spine surgery, there will be either a reduction in paraspinal muscle blood flow (ischemia) or an enhancement of this blood flow (hyperemia).

Adult↗
PubMed2001

A regulatory region rearranged BK virus is associated with tubulointerstitial nephritis in a rejected renal allograft.

A renal allograft transplant patient with high serum creatinine presented clinical symptoms of rejection. Sections of renal biopsy tissue showed mononuclear leukocyte infiltration in the tubulointerstitium and nuclear enlargement with inclusions in the tubular epithelium. The morphological characteristics resembled polyomavirus-induced interstitial nephritis. Electron microscopy of the nuclear inclusions showed paracrystalline arrays of naked viral particles with a diameter of 45 nm. Molecular studies revealed that a new variant of BK virus (BKV) with rearrangement at the regulatory region was involved in the nephritis. The BKV regulatory region contained a tandem repeat from the P-block to the Q-block causing duplication of several important transcriptional elements or transcriptional factor binding motifs. This is the first report to show a naturally occurring BKV variant with regulatory region rearrangement associated with tubulointerstitial nephritis.

Adult↗
PubMed2001

Glycosides and xanthine oxidase inhibitors from Conyza bonariensis.

Fractionation of the xanthine oxidase inhibitory methanol extract of Conyza bonariensis afforded three glycosides, in addition to nine known compounds including amyrin, beta-sitostero1 daucosterol, syringic acid 3-hydroxy-5-methoxybenzoic acid, eugenol 4-O-glucopyranoside, and luteolin, apigenin and takakin 8-O-glucuronide. The structures of the glycosides were established by a combination of spectroscopic methods (IR, MS, 1H and 13C NMR, DEPT, COSY, HMQC and HMBC) as 4-hydroxypyridin-3-carboxylic acid 4-O-glucopyranoside, 8-hydroxy-6,7-dihydrolinalool 8-O-glucopyranoside and bonaroside [viz. 1,3,4,12-tetrahydroxy-2-(9-hexadecenoylamino)octadecane 1-O-glucopyranoside]. The in vitro enzyme assay showed that syringic acid and takakin 8-O-glucuronide displayed weak inhibitory activity against xanthine oxidase with IC50 values of 500+/-41 microM and 170+/-12 microM, respectively.

Asteraceae↗
PubMed2001

Vitamin B6 intakes and status assessment of elderly men and women in Taiwan.

Studies have indicated that vitamin B6 status decreases with age. However, little is known about vitamin B6 status of elderly people in Taiwan. The purpose of this study was to assess vitamin B6 status of elderly Taiwanese and to examine the effect of protein on various indices of vitamin B6 status in the elderly. Thirty-nine men (mean age = 69.9 +/- 4.2 years) and 55 women (mean age = 69.5 +/- 3.9 years) completed a 24-h diet recall. The mean total vitamin B6 intake (men: 1.7 +/- 0.9 g/day; women: 1.6 +/- 1.2 g/day) was higher than the 1998 US Dietary Reference Intakes (DRI) and the current Taiwan Recommended Daily Nutrient Allowance (RDNA). Dietary energy and protein intakes were not related to any vitamin B6 status parameters in any sex groups and the pooled group. Vitamin B6 intake correlated only with erythrocyte aspartate transaminase activity coefficient (EAST-AC) in the pooled (r = -0.214, p < 0.05) group. There were no significant differences in plasma pyridoxal 5'-phosphate (PLP), erythrocyte alanine transaminase activity coefficient (EALT-AC), and EAST-AC between sex groups. Although elderly subjects had adequate mean plasma PLP concentrations, 59% of men and 55% of women had plasma PLP concentrations lower than a cutoff of 20 nmol/L. The mean EALT-AC was < 1.25 in two groups with adequate vitamin B6 status. However, 23% of men and 18% of women had EALT-AC values > 1.25. The mean EAST-AC value of subjects was higher than the suggested value (< 1.8) for inadequate vitamin B6 status. The incidence of biochemical vitamin B6 deficiency in our elderly is probably more relevant from other causes than from dietary intake of protein and vitamin B6.

Age Factors↗
PubMed2001

Inhibition of rat brain monoamine oxidase activities by psoralen and isopsoralen: implications for the treatment of affective disorders.

Psoralen and isopsoralen, furocoumarins isolated from the plant Psoralea corylifolia L., were demonstrated to exhibit in vitro inhibitory actions on monoamine oxidase (MAO) activities in rat brain mitochondria, preferentially inhibiting MAO-A activity over MAO-B activity. This inhibition of enzyme activities was found to be dose-dependent and reversible. For MAO-A, the IC50 values are 15.2 +/- 1.3 microM psoralen and 9.0 +/- 0.6 microM isopsoralen. For MAO-B, the IC50 values are 61.8 +/- 4.3 microM psoralen and 12.8 +/- 0.5 microM isopsoralen. Lineweaver-Burk transformation of the inhibition data indicates that inhibition by both psoralen and isopsoralen is non-competitive for MAO-A. The Ki values were calculated to be 14.0 microM for psoralen and 6.5 microM for isopsoralen. On the other hand, inhibition by both psoralen and isopsoralen is competitive for MAO-B. The Ki values were calculated to be 58.1 microM for psoralen and 10.8 microM for isopsoralen. These inhibitory actions of psoralen and isopsoralen on rat brain mitochondrial MAO activities are discussed in relation to their toxicities and their potential applications to treat affective disorders.

Affective Disorders, Psychotic↗
PubMed2001

Lamivudine is effective for the treatment of reactivation of hepatitis B virus and fulminant hepatic failure in renal transplant recipients.

Lamivudine is a potent inhibitor of hepatitis B virus (HBV) replication. The aim of this study is to elucidate the effectiveness of lamivudine for the treatment of HBV reactivation with or without fulminant hepatic failure in renal transplant recipients. Forty-two renal transplant recipients (30 men, 12 women) were enrolled onto this study. Eight patients presented with HBV reactivation without fulminant hepatic failure and were administered lamivudine (group I), 5 patients presented with HBV and hepatic failure and were administered lamivudine (group II), 5 patients presented with HBV and hepatic failure but were not administered lamivudine (group III), and 24 patients were asymptomatic HBV carriers who were not administered lamivudine (group IV). Lamivudine was administered at a dose of 100 or 150 mg once daily. A greater prevalence of recent use of a combination of antilymphocyte immunoglobulin (ALG) and methylprednisolone (MP) occurred in patients with hepatic failure (groups II and III) than those without hepatic failure (30% versus 6.3%; P = 0.043). However, there was no significant difference in the incidence of MP use alone (20% versus 25%; P = 0.746). Mortality rates for groups I, II, and III were significantly different (12.5%, 40%, 100%; P = 0.008). One patient in group I died of sepsis without evidence of HBV DNA, even in the terminal event. In group II, 3 of 5 patients (60%) were rescued by lamivudine therapy. In group III, without lamivudine treatment, there was a 100% mortality rate despite intensive plasmapheresis. HBV DNA was not detectable after lamivudine treatment in 7 of 8 patients in group I and 3 of 5 patients in group II. Creatinine levels did not change significantly during lamivudine treatment. Hepatitis B surface antigen and hepatitis B e antigen seroconversion rates after lamivudine treatment were 7.7% and 37.5%, respectively. We conclude that ALG is a potent trigger of HBV-related fulminant hepatic failure in renal transplant recipients, whereas lamivudine is an effective and lifesaving treatment. Prompt use of lamivudine is recommended in renal transplant recipients with evidence of HBV reactivation to prevent catastrophic fulminant hepatic failure.

Adolescent↗
PubMed2001

Monoamine oxidase inhibitors from rhizoma of Coptis chinensis.

Three protoberberine alkaloids jatrorrhizine, berberine and palmatine were isolated from the monoamine oxidase (MAO) inhibitory fraction of the methanol extract of Coptis chinensis rhizoma. Jatrorrhizine was shown to inhibit non-competitively both MAO-A and -B from rat brain mitochondria with the IC50 values of 4 and 62 microM, respectively. Berberine only competitively inhibited MAO-A with an IC50 values of 126 microM whereas palmatine exhibited, up to 200 microM, no inhibition on any type of the enzyme. The structure-activity relationship was briefly discussed.

Berberine Alkaloids↗
PubMed2001

Inhibition of xanthine and monoamine oxidases by stilbenoids from Veratrum taliense.

The bioassay guided refractionation of the methanol extract of roots and rhizomes of Veratrum taliense (Liliaceae) yielded five stilbenoids: veraphenol, resveratrol, piceid, isorhapontin, and mulberroside E, all inhibiting xanthine oxidase (XO, EC 1.2.3.2.) in vitro in a dose-dependent manner with IC50 values of 11.0, 96.7, 66.1, 70.0, and 78.4 microM, respectively. Veraphenol and mulberroside E were found to be mixed XO inhibitors with the Ki and Ki data of the former being 32.8 and 239.3 microM, and those of latter 32.5 and 13.8 microM, respectively. However, the inhibition on the enzyme by resveratrol, isorhapontin, and piceid was shown to be competitive with their Ki values of 9.7, 19.1, and 14.3 microM, respectively. Among the five stilbenoids, veraphenol and resveratrol were also revealed to inhibit competitively monoamine oxidase A (MAO, EC 1.4.3.4) with IC50 values at 38.0 and 26.6 microM, and Ki data 36.4 and 47.3 microM, respectively. However, none of the stilbenoids was inhibitory on MAO B in our assay. The structure-activity relationship examination showed that glycosylation of the stilbenoids could reduce the inhibition on XO and diminish the activity against MAO A, indicating that the free phenolic hydroxy group of the compounds was most likely essential for these bioactivities.

Animals↗
PubMed2001

Nutritional status of functionally dependent and nonfunctionally dependent elderly in Taiwan.

OBJECTIVE: The purpose of this study was to measure and compare nutritional status of the functionally dependent elderly with those nonfunctionally dependent elderly by assessing nutrient intake, anthropometric measurements, hematological and biochemical parameters, and the nutritional risk index (NRI). METHODS: Ninety-six volunteers (42 functionally dependent elderly, 54 nonfunctionally dependent elderly) participated in this study. The items of activity of daily living (ADL) were assessed to determine functional status. Demographic and health data were collected at the time of interview. Subjects completed 24-hour diet recall and food frequency questionnaires. Height, weight and skinfold thickness measurements were taken. Hematological and biochemical parameters were measured. The NRI was then calculated. RESULTS: Osteoporosis and hypertension were the most frequently reported chronic diseases. A small proportion of the elderly with functional dependence (9.5%) and with nonfunctional dependence (13%) had a body mass index (BMI) (< or = 21 kg/m2), indicating they were underweight. There were no significant differences in nutrient intake between the two groups. However, a higher percentage of the functionally dependent elderly had a nutrient intake of less than 75% of the Taiwan Recommended Daily Nutrient Allowance (RDNA). The functionally dependent group had a higher prevalence of malnutrition than the nonfunctionally dependent group (44.7% vs. 25%) based on the NRI. CONCLUSIONS: These functionally dependent elderly people exhibited a poorer nutritional status than the nonfunctionally dependent elderly. The elderly with functional dependence were at risk for inadequate iron intake and abnormal serum triglyceride concentrations: they were also at greater risk for chronic diseases and had a greater need for medications.

Activities of Daily Living↗
PubMed2001

Hypertensive caudate hemorrhage prognostic predictor, outcome, and role of external ventricular drainage.

BACKGROUND AND PURPOSE: The purpose of the present study was to analyze the outcome and outcome predictors of caudate hemorrhage and role of external ventricular drainage in acute hydrocephalus. METHODS: Clinical data from 36 consecutive patients with hypertensive caudate hemorrhage was used in the present study. Age, gender, volume of parenchymal hematoma, hematoma in the internal capsule, initial Glasgow Coma Scale (GCS), hydrocephalus, severity of intraventricular hemorrhage, and hemorrhagic dilatation of the fourth ventricle were analyzed for effect on outcome. Effect of external ventricle drainage for hydrocephalus was evaluated by comparing preoperative and postoperative GCS scores. RESULTS: By univariate analyses, poor outcome was associated with a poor initial GCS score (P=0.016), hydrocephalus (P<0.001), intraventricular hemorrhage severity (P<0.01), and hemorrhagic dilatation of the fourth ventricle (P=0.02). By multivariate analysis, stepwise logistic regression revealed that hydrocephalus was the only independent prognostic factor for poor outcome (P<0.001). Postoperative 48-hour GCS score was better than the preoperative score by use of paired-sample t test (P<0.001). CONCLUSIONS: Hydrocephalus is the most important predictor of poor outcome. External ventricular drainage response for hydrocephalus was good in the present study, whereas an early decision should be made regarding preoperative neurological condition.

Basal Ganglia Hemorrhage↗
PubMed2001

Hydatidosis in a Chapman's zebra (Equus burchelli antiquorum).

A 14-year-old male Chapman's zebra had been treated for a cervical granulomatous cellulitis for 3 months prior to sudden death associated with myocardial fibrosis. Incidental findings at necropsy included multiple 3-8-cm unilocular cysts in the liver and lungs. Cysts contained either a clear fluid with or without hydatid sand or a gelatinous substance with foci of mineralization. Light and scanning electron microscopic examination of the hydatid sand revealed free protoscolices as well as intact and ruptured brood capsules with protoscolices attached to the germinal membrane. The protoscolices had 2 rows of 36-38 rostellar hooks with a length of 25-30 microm. The cyst wall consisted of inner germinal, intermediate laminated, and outer adventitial layers. Hydatidosis caused by Echinococcus granulosus was diagnosed based on the unilocular cysts, multiple protoscolices formed in a brood capsule, typical trilayered cyst wall, and herbivorous intermediate host. This is the first reported case of animal hydatidosis in Taiwan. The infection is thought to have been established 12 years ago in South Africa prior to importation.

Animals↗
PubMed2001

Spectral characteristics of rice plants infested by brown planthoppers.

Spectral characteristics of rice plants at various levels of infestation by the brown planthopper, Nilaparvata lugens (Stål), (Homoptera:Delphacidae), in the early grain-filling stage were measured and analyzed using a spectroradiometer. Plant damage was classified into six scales, i.e., 0 (CK), 1, 3, 5, 7 and 9, based on the scale of infestation displayed on the surfaces of plant parts. Results showed that mean curves of reflectance spectra (350 - 1800 nm) from different scales of insect infestation were clearly differentiated, especially in the region of 737 - 925 nm, where reflectance was in the order of severity. There were significant differences in reflectance among infestations at wavelengths of 755 and 890 nm particularly. Spectral parameters such as the normalized difference vegetation index (NDVI) and cumulative reflectance may also be used to discriminate levels of infestation. Twelve wavelengths from apparent peaks and valleys of individual spectra were selected as characteristic wavelengths making up the spectral signature of each infestation.

Animals↗
PubMed2000

Patterns of palmar skin temperature alterations during transthoracic endoscopic T2 sympathectomy for palmar hyperhidrosis.

Transthoracic endoscopic T2 sympathectomy has been widely applied to the treatment of a variety of sympathetically mediated disorders. Palmar hyperhidrosis is probably the most common indication for thoracic sympathectomy, especially in certain subtropical areas. Which sympathetic ganglion is to be ablated and how extensive such ablation is enough to eliminate palm sweating are two important issues. Intraoperative monitoring of palmar skin temperature (PST) is the most frequently used method for assessing the accuracy as well as adequacy of ablation of the target sympathetic ganglia. With continuous monitoring of bilateral PST during the operative course of T2 sympathectomy, it was possible to depict the alterations of bilateral PST in response to specific surgical procedures in a real-time manner. For each case, a PST graph was obtained, which represented the graphical expression of intraoperatively recorded bilateral PST data plotted against time. The PST graphs of 93 consecutive cases were analysed. Three types of PST graphs existed, reflecting different responses of bilateral PST to different surgical procedures during the operation. In Type I PST graph pattern, found in 58 cases, skin incision and intercostal muscle dissection caused dramatic bilateral PST drop; and unilateral T2 sympathectomy induced synchronous bilateral PST elevation. Twenty-four cases demonstrated Type II PST graph pattern, in which unilateral T2 sympathectomy caused only ipsilateral PST elevation, although the PST-depressing effect of skin incision and muscle dissection was as significant as in Type I graph pattern. In the 11 cases who showed Type III PST graph pattern, neither skin incision nor T2 sympathectomy induced any apparent changes of PST on either side, giving rise to two rather flat PST curves on the PST graphs. These findings implicate that reciprocal interactions between bilateral sympathetic activities exist in the majority of cases, and that crossover sympathetic modulation may play a role in the neural control of the sudomotor and vasomotor activities of the palms. This study also provides information regarding how PST would possibly change following specific surgical procedures during transthoracic endoscopic T2 sympathectomy, which may be of importance to those who use intraoperative PST monitoring as a guide in determining whether or not the correct sympathetic ganglia are ablated for adequate sympathetic denervation of the palms.

Adolescent↗
PubMed2000

Cost-effectiveness of radiofrequency ablation for supraventricular tachycardia.

BACKGROUND: Radiofrequency ablation is an established but expensive treatment option for many forms of supraventricular tachycardia. Most cases of supraventricular tachycardia are not life-threatening; the goal of therapy is therefore to improve the patient's quality of life. OBJECTIVE: To compare the cost-effectiveness of radiofrequency ablation with that of medical management of supraventricular tachycardia. DESIGN: Markov model. DATA SOURCES: Costs were estimated from a major academic hospital and the literature, and treatment efficacy was estimated from reports from clinical studies at major medical centers. Probabilities of clinical outcomes were estimated from the literature. To account for the effect of radiofrequency ablation on quality of life, assessments by patients who had undergone the procedure were used. TARGET POPULATION: Cohort of symptomatic patients who experienced 4.6 unscheduled visits per year to an emergency department or a physician's office while receiving long-term drug therapy for supraventricular tachycardia. TIME HORIZON: Patient lifetime. PERSPECTIVE: Societal. INTERVENTIONS: Initial radiofrequency ablation, long-term antiarrhythmic drug therapy, and treatment of acute episodes of arrhythmia with antiarrhythmic drugs. OUTCOME MEASURES: Costs, quality-adjusted life-years, life-years, and marginal cost-effectiveness ratios. RESULTS OF BASE-CASE ANALYSIS: Among patients who have monthly episodes of supraventricular tachycardia, radiofrequency ablation was the most effective and least expensive therapy and therefore dominated the drug therapy options. Radiofrequency ablation improved quality-adjusted life expectancy by 3.10 quality-adjusted life-years and reduced lifetime medical expenditures by $27 900 compared with long-term drug therapy. Long-term drug therapy was more effective and had lower costs than episodic drug therapy. RESULTS OF SENSITIVITY ANALYSIS: The findings were highly robust over substantial variations in assumptions about the efficacy and complication rate of radiofrequency ablation, including analyses in which the complication rate was tripled and efficacy was decreased substantially. CONCLUSIONS: Radiofrequency ablation substantially improves quality of life and reduces costs when it is used to treat highly symptomatic patients. Although the benefit of radiofrequency ablation has not been studied in less symptomatic patients, a small improvement in quality of life is sufficient to give preference to radiofrequency ablation over drug therapy.

Adult↗