Biomedical subjects

Chang Yu

Publications and source records attributed to Chang Yu.

14 recordsLinked to original sources

PubMed2006

Angiotensin II induces interleukin-6 in humans through a mineralocorticoid receptor-dependent mechanism.

This study tested the hypothesis that angiotensin promotes oxidative stress and inflammation in humans via aldosterone and the mineralocorticoid receptor. We measured the effect of intravenous aldosterone (0.7 mug/kg per hour for 10 hours followed by 0.9 mug/kg per hour for 4 hours) and vehicle in a randomized, double-blind crossover study in 11 sodium-restricted normotensive subjects. Aldosterone increased interleukin (IL)-6 (from 4.7+/-4.9 to 9.4+/-7.1 pg/mL; F=4.94; P=0.04) but did not affect blood pressure, serum potassium, or high-sensitivity C-reactive protein. We next conducted a randomized, double-blind, placebo-controlled, crossover study to measure the effect of 3-hour infusion of angiotensin II (2 ng/kg per minute) and norepinephrine (30 ng/kg per minute) on separate days after 2 weeks of placebo or spironolactone (50 mg per day) in 14 salt-replete normotensive subjects. Angiotensin II increased blood pressure (increase in systolic pressure: 13.7+/-7.5 and 15.2+/-9.4 mm Hg during placebo and spironolactone, respectively; P<0.001 for angiotensin II) and decreased renal plasma flow (-202+/-73 and -167+/-112 mL/min/1.73 kg/m(2); P<0.001 for angiotensin II effect) similarly during placebo and spironolactone. Spironolactone enhanced the aldosterone response to angiotensin II (increase of 17.0+/-10.6 versus 9.0+/-5.7 ng/dL; P=0.002). Angiotensin II transiently increased free plasma F(2)-isoprostanes similarly during placebo and spironolactone. Angiotensin II increased serum IL-6 concentrations during placebo (from 1.8+/-1.1 to 2.4+/-1.4 pg/mL; F=4.5; P=0.04) but spironolactone prevented this effect (F=6.4; P=0.03 for spironolactone effect). Norepinephrine increased blood pressure and F(2)-isoprostanes but not aldosterone or IL-6. Aldosterone increases IL-6 in humans. These data suggest that angiotensin II induces IL-6 through a mineralocorticoid receptor-dependent mechanism in humans. In contrast, angiotensin II-induced oxidative stress, as measured by F(2)-isoprostanes, is mineralocorticoid receptor independent and may be pressor dependent.

Adult↗

PubMed2006

[Effects of a JAK inhibitor, AG490, on proliferation and survivin expression of breast cancer cell line MDA-MB-231].

BACKGROUND & OBJECTIVE: Many researches have proven that Survivin is expressed abundantly and is involved in tumorigenesis and prognosis of breast cancers. However, the signal transduction pathway of Survivin in breast cancer cells is still not clear. This study was to investigate the effects of AG490, a JAK enzyme inhibitor, on the expression of Survivin and on the proliferation and apoptosis of human breast cancer cell line MDA-MB-231. METHODS: MDA-MB-231 cells were treated with AG490. The protein levels of P-STAT3 and Survivin were detected by Western blot; the mRNA level of survivin was measured by reverse transcription-polymerase chain reaction (RT-PCR). Cell proliferation was detected by MTT; cell apoptosis was detected by flow cytometry (FCM). RESULTS: AG490 reduced the expression of P-STAT3 and Survivin, inhibited cell proliferation and induced apoptosis in MDA-MB-231 cells. When treated with 40 micromol/L AG490 for 24 h, the protein level of P-STAT3 was decreased from 0.74 to 0.21, and that of Survivin was decreased from 1.09 to 0.28. The "sub-G1" peak appeared and the apoptosis rate was 5.62% at 24 h, and further reached 28.81% at 48 h. CONCLUSION: AG490 could induce apoptosis and reduce the expression of Survivin in breast cancer MDA-MB-231 cells.

Apoptosis↗

PubMed2006

[The relationship between early childhood caries and child temperament].

OBJECTIVE: To evaluate the differences in temperament between children with early childhood caries (ECC) and an age-matched children without ECC. METHODS: A total of 219 3-year-old children were selected in urban areas of Beijing, who were physically and mentally healthy. There were 109 children in ECC group, who had unfilled caries in 1 or more surfaces in primary maxillary anterior teeth, and 110 children without caries. The children were examined for ECC levels, and their parents were asked to complete the NYLS Temperament Scale questionnaire. Then the data was collected and analyzed. RESULTS: Children with difficult, intermediate high or slow-to-warm-up temperament had more severe caries than children with easy or intermediate low temperament. There was a significant difference in temperament attribute "Activity level" between male children with ECC and without ECC. There was a significant difference in temperament attribute "Rhythmicity" between female children with ECC and without ECC. CONCLUSIONS: There were some differences in temperament between 3-year-old children with ECC and without ECC in urban areas of Beijing.

Child, Preschool↗

PubMed2005

Differing effects of mineralocorticoid receptor-dependent and -independent potassium-sparing diuretics on fibrinolytic balance.

This study tests the hypothesis that spironolactone influences plasminogen activator inhibitor-1 (PAI-1) concentrations through mineralocorticoid receptor antagonism rather than through changes in potassium. Effects of spironolactone (50 mg per day) and triamterene (50 mg per day) on fibrinolytic balance were compared in 18 normotensive and 20 hypertensive subjects pretreated with hydrochlorothiazide (HCTZ; 12.5 mg per day). Blood pressure and serum potassium were similar in spironolactone and triamterene treatment groups. The effect of the 2 drugs on the renin-angiotensin-aldosterone system was also similar. In contrast, spironolactone and triamterene exerted opposing effects on PAI-1 antigen (P=0.006 for drug effect). In normotensive subjects, triamterene (from 10.1+/-7.8 to 16.9+/-9.9 ng/mL at 9 am, P=0.019; from 7.6+/-5.4 to 11.5+/-7.3 ng/mL at 11 am, P=0.027; from 9.3+/-7.7 to 13.7+/-8.5 ng/mL for average of all time points, P=0.054) but not spironolactone significantly increased PAI-1 antigen. In hypertensive subjects, spironolactone significantly decreased PAI-1 antigen (from 22.0+/-23.4 to 16.7+/-19.0 ng/mL at 10 am, P=0.041; from 17.5+/-21.7 to 12.7+/-16.8 ng/mL at 11 am, P=0.043; from 20.3+/-22.6 to 16.6+/-19.7 ng/mL for average of all time points, P=0.014), whereas there was no effect of triamterene. Only spironolactone significantly decreased the molar ratio of PAI-1 to tissue-type plasminogen activator (t-PA) in hypertensive subjects. By regression analysis, predictors of mean PAI-1 response were spironolactone versus triamterene (P=0.014), hypertension (P=0.002), and PAI-1 response to HCTZ (P=0.019), with a trend for aldosterone (P=0.061). Mineralocorticoid receptor antagonism prevents the effect of activation of the renin-angiotensin-aldosterone system on PAI-1 antigen in normotensive subjects and improves fibrinolytic balance in hypertensive subjects through a potassium-independent mechanism.

Adult↗

PubMed2005

Recombinant human growth hormone improves muscle amino acid uptake and whole-body protein metabolism in chronic hemodialysis patients.

BACKGROUND: Intradialytic parenteral nutrition (IDPN), with or without exercise, has been shown to reverse the net negative whole-body and forearm muscle protein balances observed during hemodialysis. Pharmacologic doses of recombinant human growth hormone (rhGH) constitute another potential anabolic therapy in chronic hemodialysis patients. OBJECTIVE: Our goal was to examine the potential additive anabolic effects of rhGH compared with IDPN and exercise on protein and energy homeostasis. DESIGN: We studied 7 chronic hemodialysis patients in a crossover design study in which each subject participated in 2 protocols: GH (rhGH + IDPN + exercise) and no GH (IDPN + exercise). During the GH protocol, the subjects were studied after 3 daily doses of rhGH. Each subject was studied 2 h before, 4 h during, and 2 h after a hemodialysis session with the use of a primed, constant infusion of l-[1-(13)C]leucine. RESULTS: Whole-body net protein balance was -0.50 +/- 0.07 mg x kg fat-free mass(-1) x min(-1) when the patients did not receive rhGH and -0.39 +/- 0.04 mg x kg fat-free mass(-1) x min(-1) when the patients received rhGH, a 22% improvement in prehemodialysis whole-body protein homeostasis (P < 0.05). Essential amino acid muscle loss was also significantly less during the prehemodialysis period when rhGH was administered (-18 +/- 23 compared with -71 +/- 20 mmol/L; P < 0.05). The whole-body anabolic effects of rhGH observed during the prehemodialysis period persisted throughout the entire study, as evidenced by a lack of significant interaction or main effect of treatment during hemodialysis and in the posthemodialysis period. CONCLUSION: rhGH improves whole-body protein homeostasis in chronic hemodialysis patients.

Adult↗

PubMed2005

The incidence of upper gastrointestinal adverse events in clinical trials of etoricoxib vs. non-selective NSAIDs: an updated combined analysis.

OBJECTIVE: In spite of numerous studies demonstrating the serious gastrointestinal (GI) toxicity associated with non-selective non-steroidal anti-inflammatory drugs (NSAIDs), many patients at high GI risk continue to receive prescriptions for these drugs, often without gastroprotective agents. Etoricoxib, a COX-2 specific inhibitor, was developed to provide similar efficacy and less GI toxicity than non-selective NSAIDs. We compared the incidence of upper GI Perforations, symptomatic gastroduodenal Ulcers, and upper GI Bleeding (PUBs) in a combined analysis of all randomized, double-blind, clinical trials of chronic treatment with etoricoxib versus NSAIDs completed by June 2003. RESEARCH DESIGN AND METHODS: Data for 5441 individual subjects with osteoarthritis, rheumatoid arthritis, or ankylosing spondylitis were pooled from all 10 multinational etoricoxib trials completed by June 2003. Information on suspected PUBs was prospectively collected in all protocols, and all investigator-reported PUBs were judged by a blinded, external adjudication committee using pre-specified criteria. PUBs were analyzed using COX proportional hazards models using terms for treatment and known PUB risk factors. MAIN OUTCOME MEASURE: The incidence of confirmed PUBs among patients treated with etoricoxib 60 mg, 90 mg, or 120 mg (combined N=3226) was compared to that among patients treated with ibuprofen, diclofenac, or naproxen (combined N=2215). RESULTS: The incidence of PUBs over 44.3 months was significantly lower with etoricoxib vs. NSAIDs [cumulative incidence 1.24% vs. 2.48%, p < 0.001; rate/100 patient-years 1.00 vs. 2.47; relative risk 0.48, 95% Confidence Interval (CI) 0.32, 0.73]. Results of analysis of events occurring during the first year of treatment and subgroup analyses were consistent with the primary result. CONCLUSIONS: Treatment with etoricoxib was associated with a significantly lower incidence of PUBs than was treatment with non-selective NSAIDs. The difference was consistent in subgroups of patients defined by a variety of known risk factors.

Anti-Inflammatory Agents, Non-Steroidal↗

PubMed2005

Clinical effects of glass ionomer restorations on residual carious dentin in primary molars.

PURPOSE: To evaluate the mineralization and morphology of residual (infected and affected) carious dentin following the restoration of vital primary molars with viscous glass-ionomer cement (GIC). METHODS: Encapsulated Fuji IX GP and Ketac-Molar Aplicap GICs were placed in cavities that were prepared using the atraumatic restorative treatment (ART) approach. Four suitable exfoliated teeth with intact restorations were sectioned and then examined by electron probe microanalysis (EPMA) and scanning electron microscopy (SEM). RESULTS: EPMA demonstrated the presence of fluorine and strontium that had penetrated into the underlying residual carious dentin from the adjacent GIC. The concentrations of these two elements, and those of calcium and phosphorous, varied with distance from the GIC/dentin interface. SEM showed varying degrees of dentin tubule destruction and intratubular (peritubular) dentin present immediately subjacent to the GIC/dentin interface. Incomplete removal of carious dentin was observed in all specimens, and GIC remained adherent to the tissue.

Analysis of Variance↗

PubMed2004

Cerebral activation of mitogen-activated protein kinases after circulatory arrest and low flow cardiopulmonary bypass.

OBJECTIVES: Mitogen-activated protein kinases (MAPK) are important intermediates in the signal transduction pathways involved in neuronal dysfunction following cerebral ischemia-reperfusion injury. One subfamily, extracellular regulated kinase 1/2, has been heavily implicated in the pathogenesis of post-ischemic neuronal damage. However, the contribution of extracellular regulated kinase 1/2 to neuronal damage following deep hypothermic circulatory arrest and low flow cardiopulmonary bypass is unknown. We attempted to correlate the extent of neuronal damage present following deep hypothermic circulatory arrest and low flow cardiopulmonary bypass with phosphorylated extracellular regulated kinase 1/2 expression in the cerebral vascular endothelium. METHODS: Piglets underwent normal flow cardiopulmonary bypass (n=4) deep hypothermic circulatory arrest (n=6) and low flow cardiopulmonary bypass (n=5). Brains were harvested following 24 h of post-cardiopulmonary bypass recovery. Cerebral cortical watershed zones, hippocampus, basal ganglia, thalamus, cerebellum, mesencephalon, pons and medulla were evaluated using hematoxylin and eosin staining. A section of ischemic cortex was evaluated by immunohistochemistry with rabbit polyclonal antibodies against phosphorylated extracellular regulated kinase 1/2. RESULTS: Compared to cardiopulmonary bypass controls, the deep hypothermic circulatory arrest and low flow cardiopulmonary bypass piglets exhibited diffuse ischemic changes with overlapping severity and distribution. Significant neuronal damage occurred in the frontal watershed zones and basal ganglia of the deep hypothermic circulatory arrest group (P<0.05). No detectable phosphorylated extracellular regulated kinase 1/2 immunoreactivity was found in the cardiopulmonary bypass controls; however, ERK 1/2 immunoreactivity was present in the cerebral vascular endothelium of the deep hypothermic circulatory arrest and low flow cardiopulmonary bypass groups. CONCLUSIONS: Our results indicate that phosphorylated extracellular regulated kinase 1/2 may play a prominent role in early cerebral ischemia-reperfusion injury and endothelial dysfunction. The pharmacologic inhibition of extracellular regulated kinase 1/2 represents a new and exciting opportunity for the modulation of cerebral tolerance to low flow cardiopulmonary bypass and deep hypothermic circulatory arrest.

Animals↗

PubMed2004

Ulcer formation with low-dose enteric-coated aspirin and the effect of COX-2 selective inhibition: a double-blind trial.

BACKGROUND & AIMS: We assessed the risk of ulcers with low-dose aspirin and the interaction of low-dose aspirin with a COX-2 selective inhibitor in a double-blind trial that compared placebo, low-dose aspirin, rofecoxib + low-dose aspirin, and ibuprofen. METHODS: Osteoarthritis patients > or =50 years of age without ulcers or erosive esophagitis at baseline endoscopy were assigned randomly to placebo, enteric-coated aspirin 81 mg/day, rofecoxib 25 mg combined with aspirin 81 mg/day, or ibuprofen 800 mg 3 times a day. Repeat endoscopies were performed at 6 and 12 weeks. RESULTS: The 12-week cumulative incidence of ulcers was placebo (N = 381) 5.8%, aspirin (N = 387) 7.3%, rofecoxib combined with aspirin (N = 377) 16.1%, and ibuprofen (N = 374) 17.1% (P < 0.001 for rofecoxib combined with aspirin and for ibuprofen vs. each of placebo and aspirin). Over 12 weeks, mean increases in the number of erosions were placebo 0.17, aspirin 0.85 (P = 0.002 vs. placebo), rofecoxib combined with aspirin 1.67, and ibuprofen 1.91 (both P < 0.001 vs. aspirin and placebo). CONCLUSIONS: Low-dose aspirin alone did not significantly increase ulcer incidence. Addition of a cyclooxygenase-2 (COX-2) selective inhibitor to low-dose aspirin increased ulcer incidence, to a rate not significantly less than a nonselective nonsteroidal anti-inflammatory drug (NSAID) alone. Determining the relative impact of COX-2 selective inhibitors and nonselective NSAIDs on gastrointestinal mucosal injury in low-dose aspirin users will require further study.

Aged↗

PubMed2003

An alternative design of locked percutaneous device for skeletal extension through skin.

A skeletal extension bar (SEB) through the skin may be involved with many treatments of orthopedic diseases. A new locked percutaneous device (LPD), LPD-III, was designed for the SEB not only to allow the skin to bind onto the SEB, similarly to the LPD, but also to allow the skin binding to shift up or down the SEB while the body changes weight. Two designs of LPD-III were tried. The LPD-III-F was made from a formation of nylon hooks, fixed directly onto the SEB surface. Soft tissue can lock and shift onto the hook formation naturally. The LPD-III-S was made by attaching a stainless steel spring as a single row of rings on a nylon sleeve. Tissue can lock through the spring rings and the nylon sleeve can be manually shifted on the SEB to follow the change of thickness of soft tissue. The SEB is a stainless steel bar implanted in the sheep ilium through the skin and buttock. Two sheep were employed, both implanted with a SEB with LPD-III-F in one ilium and another SEB with LPD-III-S in the other ilium. Our experiment demonstrates that: first, both designs, LPD-III-F and LPD-III-S, function well as a skin junction shifting device; second, the LPD-III-F has abilities to re-bind the skin that not only repair damaged binding junction but also shift the skin binding up to overcome skin downgrowth; and third, powerful evidence certifies again that the mechanical connection exists in LPD.

Adipose Tissue↗

PubMed2003

The gastrointestinal safety of the COX-2 selective inhibitor etoricoxib assessed by both endoscopy and analysis of upper gastrointestinal events.

OBJECTIVES: Etoricoxib is a selective cyclooxygenase inhibitor that in clinical studies has improved the signs and symptoms of osteoarthritis and rheumatoid arthritis and reduced the potential for GI injury. The incidence of endoscopically detected ulcers and of clinically important upper GI events (perforations, ulcers, and bleeding episodes) was compared in patients taking etoricoxib or nonselective nonsteroidal anti-inflammatory drugs (NSAIDs). METHODS: Upper GI endoscopy was performed at intervals over 12 wk in 680 patients taking etoricoxib 120 mg once daily, ibuprofen 800 mg three times daily, or placebo in a randomized, parallel-group, double-blind study. Survival analysis was used to analyze time-to-event data for the incidence of gastric or duodenal ulcers (> or =3 mm and > or =5 mm), and the log rank test was used to compare the cumulative incidence between treatment groups. A combined analysis of upper GI events in all 10 Phase II/III clinical trials of etoricoxib (60, 90, or 120 mg) versus nonselective NSAIDs (naproxen, ibuprofen, or diclofenac) for osteoarthritis, rheumatoid arthritis, and chronic low back pain was conducted. Investigators reported potential events for adjudication by an external, blinded committee, using prespecified criteria to confirm events. All events that occurred during active treatment periods (maximum 792 days) or within 14 days of stopping treatment were included in the analysis. Time to first event was evaluated using survival analysis; the Kaplan-Meier method was used to determine the cumulative incidence, and relative risk was estimated with the Cox proportional hazards model. RESULTS: In the endoscopy study, the cumulative incidence of ulcers >/=3 mm at 12 wk in the ibuprofen group (17%) was significantly higher than in the etoricoxib group (8.1%, p < 0.001); similar results were seen for ulcers >/=5 mm. In the placebo group, the rate of ulcers >/=3 mm was 1.86%. Of 3142 patients treated with once-daily etoricoxib and 1828 patients treated with a nonselective NSAID (ibuprofen, naproxen, or diclofenac), 82 patients with investigator-reported upper GI events (71 confirmed) were eligible for the combined analysis. For etoricoxib versus NSAIDs, the rate per 100 patient-yr for confirmed events was 1.16 versus 3.05 (relative risk = 0.44, 95% CI = 0.27-0.72, p < 0.001), whereas that for investigator-reported events was 1.35 versus 3.42 (relative risk = 0.47, 95% CI = 0.30-0.74, p = 0.001). Results were driven primarily by studies with naproxen as the comparator. CONCLUSIONS: The incidence of endoscopically detected ulcers was significantly lower with etoricoxib 120 mg than with ibuprofen 2400 mg. Treatment with etoricoxib reduced the incidence of investigator-reported and confirmed adverse upper GI events by approximately 50% compared with treatment with nonselective NSAIDs.

Aged↗

PubMed2002

Effect of montelukast, a once-daily leukotriene receptor antagonist, on peak expiratory flow variability.

BACKGROUND: Peak expiratory flow (PEF) is an important measure of airway functin in asthma. PEF variability (PEFvar) assessment is described in asthma treatment guidelines as another means of evaluating patient status and response to therapy. OBJECTIVE: The goal of this study was to determine the clinical effect of oral montelukast, a leukotriene receptor antagonist, on PEFvar in asthmatic patients and to assess the relationship of PEFvar with other clinical measures. METHODS: This was a retrospective analysis of data from a multicenter, randomized, double-blind, placebo-controlled, parallel-group study, details of which have been published previously. Eligible patients had chronic stable asthma, had a forced expiratory volume in 1 second (FEV1) that was 50% to 85% of the predicted value, used inhaled beta-agonists, had at least 15% improvement in absolute FEV1 after inhaled beta-agonist administration, and showed a minimal predefined level of daytime asthma symptoms. Treatment consisted of a 2-week, single-blind, placebo run-in period followed by a 12-week, double-blind treatment period (montelukast 10 mg or matching placebo once daily at bedtime). RESULTS: Six hundred eighty-one patients (age range, 15-79 years) were randomized to treatment at 50 centers. Baseline PEFvar was 11.44% +/- 6.55% and 10.62% +/- 6.48% in the montelukast and placebo groups, respectively. PEFvar decreased 20.1% and 7.5% from baseline in the montelukast and placebo groups, respectively. The between-group difference was significant (P < 0.001). PEFvar had low correlation with other clinical measures. CONCLUSIONS: Over 12 weeks of treatment, montelukast significantly reduced PEFvar compared with placebo, indicating improved asthma control. The relative reduction in PEFvar was similar in patients with different degrees of variability at baseline. PEFvar did not correlate highly with other outcome variables and may measure different aspects of the disease.

Acetates↗

PubMed2002

Statistical inference for familial disease clusters.

In many epidemiologic studies, the first indication of an environmental or genetic contribution to the disease is the way in which the diseased cases cluster within the same family units. The concept of clustering is contrasted with incidence. We assume that all individuals are exchangeable except for their disease status. This assumption is used to provide an exact test of the initial hypothesis of no familial link with the disease, conditional on the number of diseased cases and the distribution of the sizes of the various family units. New parametric generalizations of binomial sampling models are described to provide measures of the effect size of the disease clustering. We consider models and an example that takes covariates into account. Ascertainment bias is described and the appropriate sampling distribution is demonstrated. Four numerical examples with real data illustrate these methods.

Adult↗

PubMed2002

Comparison of atraumatic restorative treatment and conventional cavity preparations for glass-ionomer restorations in primary molars: one-year results.

OBJECTIVE: The purpose of this study was to compare the success rates of glass-ionomer cement restorations placed with the atraumatic restorative treatment approach and conventional cavity preparation methods. METHOD AND MATERIALS: Two encapsulated, high-strength, esthetic conventional glass-ionomer cements were placed in 82 Class I and 53 Class II atraumatic restorative treatment and conventional cavity preparations, and an encapsulated amalgam alloy was placed in 32 Class I conventional preparations, in vital primary molars of 60 Chinese children aged 7 to 9 years. RESULTS: The atraumatic restorative treatment preparations, made with hand instruments only, took approximately 50% longer to complete than did the preparations completed with conventional rotary instrumentation. After 1 year, there were no amalgam failures. For the glass-ionomer cement restorations, when the atraumatic restorative treatment method was used, significantly better survival rates were found for Class I (92.9%) than for Class II (64.7%) cavity preparations. There was also a strong trend for relatively better survival rates for the conventional cavity preparation method (86.7%) than for the atraumatic restorative treatment (64.7%) method for Class II cavity preparations. However, both the atraumatic restorative treatment and conventional methods appeared equally effective for Class I preparations. CONCLUSION: In a clinic setting, the use of atraumatic restorative treatment hand instruments for cavity preparation is more time consuming, and the method may also provide less mechanical retention and/or bulk of glass-ionomer cement for some Class II preparations in primary molars than does the use of conventional rotary instruments.

Child↗