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H Chang

Publications and source records attributed to H Chang.

At least 19 recordsLinked to original sources
PubMed2006

TIMP-2 upregulates RECK expression via dephosphorylation of paxillin tyrosine residues 31 and 118.

We previously demonstrated that TIMP-2 increases the association of Crk with C3G and via subsequent activation of Rap1 enhances the expression of RECK, a membrane-anchored MMP inhibitor. In the present study, we investigate the mechanism of how the TIMP-2 signal is transduced from the alpha3beta1 integrin receptor to the Crk-C3G-Rap1 molecular complex. TIMP-2 treatment of human microvascular endothelial cells (hMVECs) increased the phosphorylation levels of Src at Tyr-527, the negative regulatory site, through enhanced association of Src with Csk. This results in the reduction of Src kinase activity and dephosphorylation of paxillin at Tyr-31/118, the target sites for Src kinase phosphorylation and also the binding sites for the downstream effector Crk. Such TIMP-2 effects accompany the disassembly of paxillin-Crk-DOCK180 molecular complex and, in turn, Rac1 inactivation. On the contrary, levels of paxillin-Crk-C3G complex formation are not reduced, rather slightly increased, which is consistent with our previous finding. Therefore, TIMP-2-mediated inhibition of Src kinase activity leads to the signaling switch from Rac1 to Rap1, thereby leading to enhanced RECK expression.

Cells, Cultured↗
PubMed2006

Long-term efficiency and stability of wetlands for treating wastewater of a lead/zinc mine and the concurrent ecosystem development.

A constructed wetland system in Guangdong Province, South of China has been used for treating Pb/Zn mine discharge since 1985. The performance in the purification of the mine discharge and the concurrent ecosystem development within the system during the period of 1985-2000 has been studied. The untreated wastewater contained rather high concentrations of cadmium (Cd) (0.05 mg L(-1)), lead (Pb) (11.5 mg L(-1)), and zinc (Zn) (14.5 mg L(-1)), which greatly exceed the upper limits for industrial wastewater discharge in China. The constructed wetland system effectively removed Cd by 94.00%, Pb by 99.04%, Zn by 97.30%, and total suspended solids (TSS) by 98.95% from the mine discharge over a long period (over 16 years) leading to significant improvement in water quality; it was also found that there were no significantly annual or monthly variations in pH values, As, Cd, Hg, Pb, and Zn concentrations in water collected from the outlet of the wetland. Moreover, diversity and abundance of living organisms, including protozoan, higher plants, terrestrial animals, and birds, increased gradually. The 16-year monitoring results showed a reciprocal relationship, at a certain extent, between restoration of the wetland ecosystem, in other words, the maturity of the wetland, and the long-term efficiency and stability on purifying heavy metal-contaminated wastewater.

China↗
PubMed2006

Myostatin expression in ventricular myocardium in a rat model of volume-overload heart failure.

BACKGROUND: Mechanical stress increases myocardial myostatin expression. However, the expression of myostatin in chronic heart failure resulting from volume-overload and after treatment with beta-blockers is little known. The authors hypothesize that myostatin plays a role in the failing myocardium because of volume-overload. MATERIALS AND METHODS: Aorto-caval shunt was created over a 4-week period in adult Sprague-Dawley rats to induce volume-overload heart failure. RESULTS: Heart weight and body weight ratio significantly increased after shunting. The left ventricular end-diastolic dimension also significantly increased. Treatment with carvedilol in the shunt group reversed the increase in heart weight and ventricular dimension to the baseline values. Myocardial and skeletal myostatin proteins were up-regulated in the shunt group. The mRNA of myocardial myostatin also increased in the shunt group. Treatment with carvedilol reversed both protein and mRNA of myocardial myostatin to the baseline values. Treatment with N-acetylcysteine and doxazosin partially decreased myostatin mRNA and protein expression as compared with the shunt group. Carvedilol normalized the increased immunohistochemical labelling of myocardial myostatin in the shunt group. CONCLUSION: Myocardial myostatin mRNA and protein expression were up-regulated in the rat model of volume-overload heart failure. Treatment with carvedilol is associated with a limitation of increased myostatin expression in the failing ventricular myocardium.

Animals↗
PubMed2006

Spontaneous massive haemothorax caused by rupture of an intercostal vein.

Spontaneous massive haemothorax is rare. We describe a healthy 44 year old woman who experience sudden onset chest pain while sleeping. Chest radiograph revealed massive right pleural effusion. Progressive dyspnoea, cold sweating, and tachycardia developed later. A tube thoracostomy was performed immediately and massive haemothorax was noted. An emergency thoracotomy was performed because of unstable vital signs. Disruption of the right third intercostal vein with continuous bleeding was observed, and suture ligation of the vein was performed. The total blood loss was about 4000 ml. The patient recovered uneventfully, and her condition at follow up visits to the outpatient department was satisfactory.

Adult↗
PubMed2005

Using an integrated infection control strategy during outbreak control to minimize nosocomial infection of severe acute respiratory syndrome among healthcare workers.

Healthcare workers (HCWs) are at risk of acquiring severe acute respiratory syndrome (SARS) while caring for SARS patients. Personal protective equipment and negative pressure isolation rooms (NPIRs) have not been completely successful in protecting HCWs. We introduced an innovative, integrated infection control strategy involving triaging patients using barriers, zones of risk, and extensive installation of alcohol dispensers for glove-on hand rubbing. This integrated infection control approach was implemented at a SARS designated hospital ('study hospital') where NPIRs were not available. The number of HCWs who contracted SARS in the study hospital was compared with the number of HCWs who contracted SARS in 86 Taiwan hospitals that did not use the integrated infection control strategy. Two HCWs contracted SARS in the study hospital (0.03 cases/bed) compared with 93 HCWs in the other hospitals (0.13 cases/bed) during the same three-week period. Our strategy appeared to be effective in reducing the incidence of HCWs contracting SARS. The advantages included rapid implementation without NPIRs, flexibility to transfer patients, and re-inforcement for HCWs to comply with infection control procedures, especially handwashing. The efficacy and low cost are major advantages, especially in countries with large populations at risk and fewer economic resources.

Cross Infection↗
PubMed2005

Use of Medicaid prescription data for syndromic surveillance--New York.

INTRODUCTION: This study explored the utility and value of Medicaid prescription data for statewide syndromic surveillance. METHODS: Daily Medicaid claims forms are transmitted to the New York State Syndromic Surveillance Project as summary counts by ZIP Code, age category, sex, and 18 medication groups. The CUSUM statistic is used to analyze the data daily at the county level with a 7-10-day moving average baseline. The system was evaluated following an outbreak of pertussis in a small institutional setting in a rural county by comparing the county's CUSUM signals for prescriptions for macrolide antibiotics with the onset of the outbreak. RESULTS: A case of pertussis was suspected on July 21, 2004, and was reported to the New York State Department of Health on July 22. Treatment and prophylaxis were initiated on July 22. CUSUM analysis flagged a county-wide increase in macrolide antibiotics on the day of treatment/prophylaxis for the first case and contacts in the outbreak. The following week, approximately 300 contacts received prophylaxis (not all of whom were Medicaid clients), resulting in CUSUM signals during the week (July 28 and 29). CONCLUSION: Medicaid prescription data are routinely collected and readily available for syndromic surveillance. This data source has shown potential value as an indicator of disease activity, as in this case study, in an area where a high concentration of Medicaid recipients reside. However, for the surveillance system to be considered a useful early warning system, additional study is required to determine the best methods for selecting from the automatically generated CUSUM signals those that might be important for public health.

Disease Outbreaks↗
PubMed2005

Genetic risk identifies multiple myeloma patients who do not benefit from autologous stem cell transplantation.

Genetic aberrations have emerged as major prognostic factors for patients with multiple myeloma (MM). We evaluated 126 MM patients for t(4;14) or t(11;14), 13q or p53 deletions and correlated the number of genetic aberrations with patient's clinical outcome following undergoing autologous stem cell transplantation. We demonstrate the significance of genetic-based risk classification that clearly segregate patients into low (no genetic abnormalities or only t(11;14)), intermediate (any one of the genetic abnormalities other than t(11;14)) and high-risk groups (any two or more of the genetic abnormalities other than t(11;14)). High-risk patients do not benefit from stem cell transplant and should be offered alternative therapies.

Adult↗
PubMed2005

A histochemical and pathological study on the interrelationship between TCDD-induced AhR expression, AhR activation, and hepatotoxicity in mice.

The objective of this study was to establish a correlation and interrelationship between aryl hydrocarbon receptor (AhR) and hepatotoxicity induced by TCDD. Young male ICR mice were exposed to TCDD via dermal exposure at doses of 0, 2.5, 25, and 125 ng TCDD twice weekly for 20 wk. Histopathological examination revealed a classic pattern and dose-dependent pathological changes in sinusoidal dilatations, hepatocellular swelling and degeneration, fatty infiltration, and hepatocellular necrosis. Immunochemical staining for AhR also demonstrated that the AhR-positive hepatocytes were centrilobular in location, especially with those cells cuffing the central vein. With exposures to TCDD, the number of AhR-positive cells increased with dose. Furthermore, we also demonstrated all the hepatocytes that exhibited pathological changes (e.g., fatty infiltration or necrosis) were AhR-positive. Depletion in AhR (AhR removal after activation) in many centrilobular hepatocytes, with disappearance of the AhR positive cuffing, was observed in the high TCDD exposed animals. AhR activation was also evident by the increase in CYP 1A2 expression in many centrilobular hepatocytes, especially those exposed to high doses of TCDD. Studies in the past, with experiments performed separately, could only suggest the association of AhR expression and hepatocellular toxicity. By examining the AhR expression, AhR activation (CYP 1A2 expression upregulation), and hepatocellular pathology together, it was possible to correlate these factors in the same animal and even in the same cells. Our finding provided direct evidence on the interaction and causal relationship between AhR activation and hepatic toxicity.

Animals↗
PubMed2005

Evaluation of blunt abdominal trauma: current practice in Taiwan.

OBJECTIVE: To gain an overview of the current practice of different major institutions in Taiwan in the evaluation of abdominal injuries. A further comparison was made between general surgeons and emergency physicians in this aspect. METHOD: A telephone survey was conducted of all emergency departments of 58 major institutions (14 medical centres, 44 district hospitals) that are capable of providing definitive care for trauma victims in Taiwan in June 2002. Respondents were asked to select the diagnostic modality of choice in the evaluation of a haemodynamically abnormal blunt trauma victim with suspected intra-abdominal injuries. In the same study period, this particular telephone scenario was also used to survey 109 individual doctors (45 emergency physicians, 64 general surgeons). RESULTS: Most respondents preferred ultrasound (also known as focused assessment with sonography for trauma or "FAST") instead of diagnostic peritoneal lavage (DPL) because DPL is invasive and most doctors in Taiwan have limited experience in performing DPL or interpreting the results. CONCLUSIONS: It seems reasonable to devote greater resources for emergency departments to incorporate a FAST based algorithm into their initial management of trauma victims, and to improve training in its use. It is also suggested that future ATLS teaching in Taiwan should include didactic material on FAST.

Abdominal Injuries↗
PubMed2005

Outcomes of febrile children presumed to be immunocompetent who present with leukopenia or neutropenia to an ambulatory setting.

UNLABELLED: To determine significant medical outcomes in febrile children presenting to an ambulatory setting with neutropenia and/or leukopenia. METHODS: Retrospective medical record review conducted on febrile patients who had a blood culture drawn, with white blood cell counts less than 5,000/mm3 and/or an absolute neutrophil count less than 1000/mm3. Ninety-one patients were identified; 5 with positive blood culture results, 13 with significant non-oncologic disease, and 3 patients with leukemia who had involvement of 2 or more cell lines. CONCLUSIONS: In the majority of patients, clinical judgment, physical findings, and review of all cell lines of the complete blood cell count identified those with significant disease.

Ambulatory Care↗
PubMed2004

Bone mass and lifestyle related factors: a comparative study between Japanese and Inner Mongolian young premenopausal women.

The purpose of this study was to evaluate the ethnic difference in bone mass between Japanese and Inner Mongolian young premenopausal women and to assess the contribution of lifestyle related and anthropometric factors to bone mass. We studied 33 Japanese and 44 Inner Mongolian healthy young women, aged 20-34 years, in urban area. Speed of sound (SOS), broadband ultrasound attenuation (BUA) and stiffness index (SI) were measured at the calcaneus using quantitative ultrasound (QUS) analysis. Age at menarche, regularity of menstruation and lifestyle related factors were estimated by a self-reported questionnaire. There were no differences between the two groups in age, height, weight, BMI, regularity of menstruation, frequency of meat intake, frequency of yellow-green vegetable intake and exercise habit. Japanese women had significantly lower age at menarche and higher proportion of milk consumption habit at junior high school, senior school and present. Before adjustment, Japanese women had significantly higher SOS and SI than Inner Mongolian women. However, after adjustment for age at menarche and milk consumption habit at junior high school, both of which were significantly different between groups, no group-differences remained in either SOS or SI. These results suggest that the differences in age at menarche and milk consumption habit at junior high school, which relate to hormonal and nutritional status during puberty, may account for the differences in bone mass between Japanese and Inner Mongolian young women.

Adult↗
PubMed2004

Bone marrow aspirates as part of routine donor assessment for allogeneic blood and marrow transplantation can reveal presence of occult hematological malignancies in otherwise asymptomatic individuals.

Pre transplant screening work-up of donors for allogeneic blood and marrow transplantation is essential in an effort to minimize risks to the recipient and protect the donor. At Princess Margaret Hospital, every potential donor is screened with a bone marrow aspirate. The case histories of three asymptomatic potential donors who presented within 1 year with normal complete blood counts, history and physical examination are presented. A 65-year-old male patient was diagnosed with smouldering multiple myeloma, a 72-year-old male patient with chronic lymphocytic leukemia and a 42-year-old male patient with myelodysplastic syndrome. Bone marrow examination led to the diagnosis in each one of these cases. Of note is that each of the potential donors was discovered to have the same disease as the transplant recipient. In vitro clonogenic hemopoietic progenitor assays were compared to those of 20 normal volunteers. Inferior growth of hemopoietic progenitor colonies in all three was noted. In conclusion, particularly in older donors and donors with potential for familial malignancies, more screening investigations including bone marrow aspiration may be reasonable to investigate for occult hematological malignancies prior to stem cell donation. Clonogenic assays can contribute to detect hemopoietic abnormalities pre transplant.

Adult↗
PubMed2004

Management of community-acquired pneumonia in persons with spinal cord injury.

STUDY DESIGN: Retrospective case series. OBJECTIVES: Respiratory disorders are the leading cause of death in persons with spinal cord injury (SCI), but the epidemiology and medical management of pneumonia in persons with chronic SCI is not well characterized. We describe the clinical presentation of persons with SCI with community-acquired pneumonia (CAP), characterize its management and compare practice to recommendations for CAP in the general population. SETTING: Three United States Veterans Affairs Medical Centers with specialized SCI services. METHODS: Chart abstraction was performed for all persons with chronic SCI seen at participating centers for treatment of CAP during a 2-year period. Collected data included presenting signs and symptoms, laboratory and imaging results, initial antibiotic therapy, secretion mobilization techniques, in-patient vs outpatient management, length of stay, and mortality. RESULTS: In all, 41 persons with SCI received treatment for CAP during the study period. A total of 32 (78.0%) patients were admitted for treatment; two (4.8%) required intubation and mechanical ventilation. Initial antibiotic coverage met guideline recommendations for only half of inpatients and infrequently provided adequate antipseudomonal coverage. Microbiologic testing was performed on 26 cases (63.4%) and demonstrated a specific pathogen in only five cases (12.2% of total). Three cases (7.3%) died during treatment for CAP, and 16 (42.1%) of 38 CAP survivors died within a median follow-up of 3 years. CONCLUSION: The majority of chronic SCI patients who present to specialized SCI centers with CAP are admitted for treatment. Short-term mortality is comparable to CAP in the general population.

Adult↗
PubMed2004

Preconsultation use of analgesics on adults presenting to the emergency department with acute appendicitis.

OBJECTIVE: 279 cases of appendicitis were reviewed and compared for the difference between those patients who received pain medication before consulting a surgeon and those who were not treated with analgesics. METHODS: All patients aged 15 years and older who underwent appendicectomy for appendicitis between 1 July 2001 and 30 June 2002 were divided into group 1 (those who received preconsultaion use of analgesics) and group 2 (those who were not treated with analgesics). The following measures were compared: age, sex, symptom duration, initial vital signs, white blood cell counts, frequency of imaging studies, time to operative intervention, and operative findings. Continuous and categorical variables were analysed using t and chi(2) tests, respectively. RESULTS: A total of 279 patients were included for analysis. Patient details (age, sex, symptom duration) of the two study groups were similar. There was no statistically significant difference between group 1 and group 2 with respect to vital signs (systolic blood pressure, pulse rate, respiratory rate, body temperature), white blood cell counts, and frequency of imaging studies (ultrasound, computed tomography). There was no significant difference in the rate of perforated appendicitis between the two study groups although a shorter median time to operative intervention has been found in the group who received analegesia. CONCLUSION: The preconsultation use of analgesics in ED patients with a final diagnosis of appendicitis is not associated with a longer delay to operative intervention and is not associated with an increased rate of perforated appendicitis.

Acute Disease↗
PubMed2004

Capsule endoscopy: a single-centre experience with the first 226 capsules.

BACKGROUND: Capsule endoscopy (CE) refers to a novel diagnostic method of imaging the gastrointestinal tract using a wireless capsule that transmits images to a data recorder while the device traverses the small intestine. OBJECTIVE: To review the authors' experience with CE to determine the indications, outcomes and management of positive findings. METHODS: Patients were prepared for CE with a single dose of magnesium citrate. Following an 8 h fast, a sensor array system was applied to the abdomen, the capsule was swallowed and the images were transmitted to a data recorder worn on the patient's side. Typically, the battery life of the capsule is 8 h, following which the data recorder is returned, downloaded to a computer workstation and reviewed. RESULTS: To date, 226 capsule studies have been performed in 209 patients. The indications included obscure bleeding (167 studies: 88 overt, 79 occult), anemia (14 studies), evaluation for inflammatory bowel disease (12 studies), screening for polyps (10 studies), pain (19 studies) and abnormal radiological imaging (4 studies). In the setting of obscure bleeding, a definitive source of bleeding was discovered in 85 studies. This included angiodysplasia (52 studies), mitotic lesions (10 studies) and ulcers (23 studies). A probable source of bleeding was found in another 10 capsule studies. In the setting of anemia without evidence of bleeding, the definitive findings included ulcers (three studies), angiodysplasia (two studies), mitotic lesions (one study) and celiac disease (one study). Of four patients with abnormal radiological imaging, CE demonstrated lesions in two. The results of 35 capsule studies led to laparotomy with curative surgical resection. In eight studies, the capsules became lodged within a stricture; none led to obstruction and three were managed endoscopically. CONCLUSION: The yield of CE in carefully selected patients with obscure bleeding approximates 51%. There appear to be few complications, and patient satisfaction appears high. Cost analysis and further studies of clinical outcomes are required to elucidate appropriate indications for this device.

Angiodysplasia↗