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Biomedical subjects

M Chang

Publications and source records attributed to M Chang.

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

Validation of the functional fitness age (FFA) index in older Japanese women.

Functional fitness age (FFA), which we previously described, is a measure of functional age that reflects a person's overall physical ability to complete daily tasks such as preparing meals and performing various household chores. The purpose of this study was to validate FFA in two elderly populations: 1) older subjects from different communities, and 2) older subjects participating in an exercise intervention program. FFA was calculated from 4 performance tests: performing arm curls; moving beans with chopsticks; demonstrating functional reach; and sitting and walking around two cones. The first study group was selected from 4 different communities (N=127), and was subdivided into a less active group (N=87) and an active group (N=40). The results of the 4 tests for the less active group were not significantly different from those for the original validation group used in developing the FFA equation. The FFA of the less active group (71.1+/-7.7 yrs) was not different from their chronological age (70.4+/-6.6 yrs). In the active group, except for the arm curls, test scores were significantly higher than those of the original validation group. The FFA of the active group (66.2+/-5.1 yrs) was significantly younger than their chronological age (70.9+/-4.2 yrs). Another group of 14 older women (79.5+/-3.9 yrs) was recruited for pre- and post-training testing. After the 3-month exercise program, they showed significant improvements in sitting and walking around two cones and functional reach; their FFA decreased significantly from 81.5+/-5.0 yrs to 78.3+/-4.5 yrs. The control group selected from the same community (N=16, 79.8+/-5.3 yrs) showed no significant changes in the 4 performance tests, and their FFA remained unchanged. These results indicate that our FFA is highly cross-validated for different Japanese communities, and is sensitive to changes associated with participation in an exercise intervention program.

Activities of Daily Living↗
PubMed2001

Abnormal duplex findings at the proximal anastomosis of infrainguinal bypass grafts: does revision enhance patency?

Using color duplex ultrasound (CDU) surveillance of autogenous infrainguinal bypasses, a peak systolic flow velocity (PSFV) ratio of greater than 3 to 1 within the graft relative to adjacent PSFV has been accepted as predicting significant stenosis mandating revision. At the proximal anastomosis, where significant vessel diameter differences and turbulent flow exist, the validity of these criteria is less clear. Our purpose was to review our experience with proximal anastomotic abnormalities in a CDU surveillance protocol. Routine CDU surveillance for all infrainguinal bypass gratis consisted of evaluation in an accredited vascular laboratory at 1 month postoperatively, every 3 months for the first year, every 6 months in the second year, and annually thereafter. Grafts with a PSFV ratio of >3 at the proximal anastomosis on any CDU study were included in this review. From our results we conclude that currently accepted CDU criteria for graft-threatening stenosis may not be valid for abnormalities at the proximal anastomosis of infrainguinal grafts. Regression of these abnormalities is common. Better CDU criteria are needed for predicting not only severity of proximal anastomotic stenosis but also likelihood of graft thrombosis.

Adult↗
PubMed2001

Multiple risk factors and population attributable risk for ischemic heart disease mortality in the United States, 1971-1992.

The objective of this study was to assess the associations and population attributable risks (PAR) of risk factor combinations and ischemic heart disease (IHD) mortality in the United States. We used logistic regression models to assess the association of risk factors with IHD in the First National Health and Nutrition Examination Survey (1971-1974) and Epidemiologic Follow-up Study (1982-1992) among white and black men and women. We examined eight modifiable risk factors: hypertension, elevated serum cholesterol, diabetes, overweight, current smoking, physical inactivity, depression, and nonuse of replacement hormones. Risk factors associated with IHD mortality were the same among white and black men (i.e., age, education, smoking, diabetes, hypertension, and serum cholesterol). Age, education, smoking, diabetes, and hypertension were the risk factors among white and black women. Physical inactivity, nonuse of replacement hormones, serum cholesterol, and overweight were the additional risk factors among white women. Adjusted for demographic risk factors, overall PARs for study risk factors were 41.2% for white men, 60.5% for white women (with five risk factors only), 49.2% for black men, and 71.2% for black women. Much IHD mortality attributable to individual risk factors is caused by those factors in combination with other risk factors; relatively little mortality is attributable to each risk factor in isolation. Analysis that does not examine risk factor combinations may greatly overestimate PARs associated with individual risk factors.

Adult↗
PubMed2001

The efficacy of 0.5% proparacaine stored at room temperature.

OBJECTIVE: To evaluate the efficacy of 0.5% proparacaine stored at room temperature for 6 weeks. ANIMALS STUDIED: Six normal dogs, evaluated on a weekly basis for 6 weeks. PROCEDURE: Proparacaine stored at 4 degrees C or at room temperature, was evaluated in the right and left eye of each dog, respectively. Corneal sensitivity was assessed with a Cochet-Bonnet aesthesiometer before and after instillation of proparacaine at each time point. RESULTS: A statistically significant difference was seen in corneal sensitivity beginning at week 3 for the eyes receiving room-temperature proparacaine compared to refrigerated proparacaine. Differences were not seen between right and left eyes before instillation of proparacaine for any time point, nor for eyes receiving refrigerated proparacaine over the 6 week study period. CONCLUSION: Short-term storage of proparacaine at room temperature did not affect efficacy, but storage at room temperature for more than 2 weeks resulted in a decrease in drug effect.

Anesthetics, Local↗
PubMed2001

Ozone predictions in Atlanta, Georgia: analysis of the 1999 ozone season.

Ozone prediction has become an important activity in many U.S. ozone nonattainment areas. In this study, we describe the ozone prediction program in the Atlanta metropolitan area and analyze the performance of this program during the 1999 ozone-forecasting season. From May to September, a team of 10 air quality regulators, meteorologists, and atmospheric scientists made a daily prediction of the next-day maximum 8-hr average ozone concentration. The daily forecast was made aided by two linear regression models, a 3-dimensional air quality model, and the no-skill ozone persistence model. The team's performance is compared with the numerical models using several numerical indicators. Our analysis indicated that (1) the team correctly predicted next-day peak ozone concentrations 84% of the time, (2) the two linear regression models had a better performance than a 3-dimensional air quality model, (3) persistence was a strong predictor of ozone concentrations with a performance of 78%, and (4) about half of the team's wrong predictions could be prevented with improved meteorological predictions.

Air Pollution↗
PubMed2001

Assaultive behavior by psychiatric in-patients and its related factors.

The purpose of this article is to explore assaultive behavior of psychiatric in-patients in a hospital and to examine the interplay of patient, environmental, and staff factors related to assault. The present study was carried out prospectively using standardized instruments applied in four acute wards in one hospital. A log system was used to record the occurrence of assaults. The results showed 595 episodes of assault from 238 patients in 7 months. Forty one nurses participated in the study. To further examine the differences between assaultive and non-assaultive patients, and assaulted and non-assaulted nurses, a logistic regression analysis was used. The results indicated that patient factors (diagnosis, history of assault, time since admission, and history of smoking), environmental factors (patient/nurse ratio and spatial density), and staff factors (age, length of work experience, training program received in prevention and management of assaults) are contributing variables to assaultive behavior. The present study examined a wider range of variables than have been included in many previous studies. This reinforces the necessary complexity of models likely to prove useful in predicting assaults among psychiatric inpatients.

Adolescent↗
PubMed2001

Transcriptional coregulation by the cell integrity mitogen-activated protein kinase Slt2 and the cell cycle regulator Swi4.

In Saccharomyces cerevisiae, the heterodimeric transcription factor SBF (for SCB binding factor) is composed of Swi4 and Swi6 and activates gene expression at the G(1)/S-phase transition of the mitotic cell cycle. Cell cycle commitment is associated not only with major alterations in gene expression but also with highly polarized cell growth; the mitogen-activated protein kinase (MAPK) Slt2 is required to maintain cell wall integrity during periods of polarized growth and cell wall stress. We describe experiments aimed at defining the regulatory pathway involving the cell cycle transcription factor SBF and Slt2-MAPK. Gene expression assays and chromatin immunoprecipitation experiments revealed Slt2-dependent recruitment of SBF to the promoters of the G(1) cyclins PCL1 and PCL2 after activation of the Slt2-MAPK pathway. We performed DNA microarray analysis and identified other genes whose expression was reduced in both SLT2 and SWI4 deletion strains. Genes that are sensitive to both Slt2 and Swi4 appear to be uniquely regulated and reveal a role for Swi4, the DNA-binding component of SBF, which is independent of the regulatory subunit Swi6. Some of the Swi4- and Slt2-dependent genes do not require Swi6 for either their expression or for Swi4 localization to their promoters. Consistent with these results, we found a direct interaction between Swi4 and Slt2. Our results establish a new Slt2-dependent mode of Swi4 regulation and suggest roles for Swi4 beyond its prominent role in controlling cell cycle transcription.

Cyclins↗
PubMed2001

Functional fitness may be related to life satisfaction in older Japanese adults.

The relationship between functional fitness status and life satisfaction was assessed in older Japanese people from the perspective of quality of life (QOL). A total of 123 older men and women (M = 74.3 years, SD = 5.4) participated in the study. The questionnaire contained 21 questions covering eight structural factors pertaining to the feelings of life satisfaction in older people. The functional fitness test consisted of nine items representing the following five areas of fitness: muscular strength, agility, coordination, balance, and flexibility. The analysis revealed no overall correlation between the total fitness and the total life satisfaction scores, but some of the life satisfaction factors were significantly related to some functional fitness items (P < .01). The results suggest it is important for older people to maintain their functional fitness in order to manage a high quality of life.

Activities of Daily Living↗
PubMed2000

The efficacy of interconnected porous hydroxyapatite in achieving posterolateral lumbar fusion in sheep.

STUDY DESIGN: An animal study was performed to evaluate lumbar spinal fusion radiologically and mechanically. OBJECTIVES: To assess the efficacy of interconnected porous hydroxyapatite in achieving posterolateral lumbar arthrodesis in sheep. SUMMARY OF BACKGROUND DATA: Posterolateral spinal arthrodesis with autologous bone graft is the gold standard procedure for lumbar fusion. The procedure for harvesting bone from the iliac crest increases morbidity. Interconnected porous hydroxyapatite has been used effectively as an alternative to cancellous bone graft material in metaphyseal bone defects. Little is known about the efficacy of interconnected porous hydroxyapatite in achieving lumbar spinal fusion. METHODS: Four groups of seven sheep underwent bisegmental posterolateral lumbar fusion with instrumentation using different intertransverse graft material. In group 1, no graft material was used. In group 2, autologous bone was used. Group 3 had interconnected porous hydroxyapatite. Group 4 had an equip of interconnected porous hydroxyapatite and autologous bone. The animals were killed at 20 weeks after surgery. Radiographs and computed tomography images were obtained. The fusion masses were graded for bone resorption and trabecular connectivity on the computed tomography images. Mechanical testing of the specimens was performed, and the three-dimensional segmental motion was measured in flexion/extension, axial rotation, and lateral bending. RESULTS: The radiographic images were difficult to interpret because of the radiodense interconnected porous hydroxyapatite granules. According to mechanical stability criteria, the fusion rate for the different groups was as follows: 100% (14/14) for the autologous bone group, 72% (10/14) for the bone/interconnected porous hydroxyapatite group, 50% (7/14) for the pure interconnected porous hydroxyapatite group, and 15% (2/14) for the sham group. CONCLUSIONS: Spinal arthrodesis using interconnected porous hydroxyapatite alone or mixed with bone as graft material reduced segmental motion. It was not, however, as effective as autologous bone graft material in achieving spinal arthrodesis. The sheep model using autologous bone achieved a 100% fusion rate. Because the nonunion rate for a single level in humans may be as high as 40%, the fusion rate with bone/interconnected porous hydroxyapatite in humans may be lower than the 72% found in the sheep model. The little resorption of the radiodense interconnected porous hydroxyapatite granules made the radiologic evaluation of the fusion masses difficult.

Animals↗
PubMed2000

Dissecting G protein-coupled receptor signaling pathways with membrane-permeable blocking peptides. Endogenous 5-HT(2C) receptors in choroid plexus epithelial cells.

To determine the intracellular signaling mechanism of the 5-HT(2C) receptor endogenously expressed in choroid plexus epithelial cells, we implemented a strategy of targeted disruption of protein-protein interactions. This strategy entails the delivery of conjugated membrane-permeable peptides that disrupt domain interaction at specific steps in the signaling cascade. As proof of concept, two peptides targeted against receptor-G protein interaction domains were examined. Only G(q)CT, which targets the receptor-G(q) protein interacting domain, disrupted 5-HT(2C) receptor-mediated phosphatidylinositide hydrolysis. G(s)CT, targeting the receptor-G(s) protein, disrupted beta2 adrenergic receptor-mediated activation of cAMP but not 5-HT(2C) receptor-mediated phosphatidylinositide hydrolysis. The peptide MPS-PLCbeta1M, mimicking the domain of phospholipase Cbeta1 (PLCbeta1) interacting with active Galpha(q), also blocked 5-HT(2C) receptor activation. In contrast, peptides PLCbeta2M and Phos that bind to and sequester free Gbetagamma subunits were ineffective at blocking 5-HT(2C) receptor-mediated phosphoinositol turnover. However, both peptides disrupted Gbetagamma-mediated alpha(2A) adrenergic receptor activation of mitogen-activated protein kinase. These results provide the first direct demonstration that active Galpha(q) subunits mediate endogenous 5-HT(2C) receptor activation of PLCbeta and that Gbetagamma subunits released from Galpha(q) heterotrimeric proteins are not involved. Comparable results were obtained with metabotropic glutamate receptor 5 expressed in astrocytes. Thus, conjugated, membrane-permeable peptides are effective tools for the dissection of intracellular signals.

Amino Acid Sequence↗
PubMed2000

Characterization of metabolites of Celecoxib in rabbits by liquid chromatography/tandem mass spectrometry.

The metabolism of the anti-inflammatory drug Celecoxib in rabbits was characterized using liquid chromatography (LC)/tandem mass spectrometry (MS/MS) with precursor ion and constant neutral loss scans followed by product ion scans. After separation by on-line liquid chromatography, the crude urine samples and plasma and fecal extracts were analyzed with turbo-ionspray ionization in negative ion mode using a precursor ion scan of m/z 69 (CF(3)) and a neutral loss scan of 176 (dehydroglucuronic acid). The subsequent product ion scans of the [M - H] ions of these metabolites yielded the identification of three phase I and four phase II metabolites. The phase I metabolites had hydroxylations at the methyl group or on the phenyl ring of Celecoxib, and the subsequent oxidation product of the hydroxymethyl metabolite formed the carboxylic acid metabolite. The phase II metabolites included four positional isomers of acyl glucuronide conjugates of the carboxylic acid metabolite. These positional isomers were caused by the alkaline pH of the rabbit urine and were not found in rabbit plasma. The chemical structures of the metabolites were characterized by interpretation of their product ion spectra and comparison of their LC retention times and the product ion spectra with those of the authentic synthesized standards.

Animals↗
PubMed2000

Continuous electronic heart rate monitoring for fetal assessment during labor.

BACKGROUND: Electronic fetal monitoring (EFM) has been widely adopted. There is debate about its overall effectiveness as well as the relative merits of routine application versus use for high-risk pregnancies only. OBJECTIVES: The objective of this review was to assess the effects of routine continuous electronic fetal monitoring during labour compared with intermittent auscultation. SEARCH STRATEGY: We searched the Cochrane Pregnancy and Childbirth Group trials register, Medline (1966 to 1994), and reference list of relevant articles. We also contacted experts in the field. SELECTION CRITERIA: Randomised trials comparing routine continuous electronic fetal monitoring with intermittent auscultation. DATA COLLECTION AND ANALYSIS: Data were extracted by one reviewer, and their accuracy was confirmed independently by a second person. A single reviewer assessed study quality based on criteria developed by others for randomised controlled trials. Data reported from similar studies were used to calculate a combined risk estimate for each of eight outcomes. MAIN RESULTS: Nine studies involving 18,561 women and their 18,695 infants were included. The trials were of variable quality. A statistically significant decrease was associated with routine continuous EFM for neonatal seizures (relative risk (RR) = 0. 51, confidence interval (CI) = 0.32,0.82). The protective effect for neonatal seizures was only evident in studies with high-quality scores. No significant differences were observed in 1-minute Apgar scores below 4, 1-minute Apgar scores below 7, rate of admissions to neonatal intensive care units, and perinatal death. An increase associated with the use of EFM was observed in the rate of cesarean delivery (RR = 1.41, CI = 1.23,1.61) and operative vaginal delivery (RR = 1.20, CI = 1.11,1.30). REVIEWER'S CONCLUSIONS: The only clinically significant benefit from the use of routine continuous EFM was in the reduction of neonatal seizures. In view of the increase in cesarean and operative vaginal deliveries, the long-term benefit of this reduction must be evaluated in the decision reached jointly by the pregnant woman and her clinician to use continuous EFM or intermittent auscultation during labor.

Cardiotocography↗
PubMed2000

Neo-self antigens and the expansion of B-1 cells: lessons from atherosclerosis-prone mice.

The pathogenesis of atherosclerosis involves an inflammatory process that is modulated by the immune system, and within these complex responses we have discerned a possible role for an archetypic B-1 clone. We speculate that due to their immunogenicity and in vivo distribution the "neo"-self determinants created in oxidatively modified LDL are highly stimulatory for certain B-1 cell clones. These neo-self determinants, which can be created chemically, by somatic processes, may in fact represent the molecular analogues of somatic maturation, or even aging. These changes, including those on non-protein antigens induced by oxidative metabolism, amongst others, create neo-determinants against which the host no doubt can not develop rigorous B-cell tolerance. The onset of expression of these oxidative neo-determinants relatively late in development may well serve a useful function for the highly evolved mammalian immune system, as targeting by evolutionarily selected B-1 clones may facilitate the amplification of other useful antibody-mediated physiologic functions. As in the case of the T15 clone, these antibodies may aid in protection against common microbial pathogens. Hence we postulate that during the evolution of the adaptive immune system the neo-self antigenic milieu may have been exploited for the natural selection of primordial clonal specificities. The T15 B-1 clone may then illustrate a common paradigm in which there has been natural selection based on utility for the defense of the individual from environmental threats, as well as for possible "housekeeping" role(s) and the maintenance of cellular homeostasis.

Animals↗
PubMed2000

Indoor and outdoor air quality investigation at schools in Hong Kong.

Five classrooms in Hong Kong (HK), air-conditioned or ceiling fans ventilated, were chosen for investigation of indoor and outdoor air quality. Parameters such as temperature, relative humidity (RH), carbon dioxide (CO2), sulphur dioxide (SO2), nitric oxide (NO), nitrogen dioxide (NO2), respirable particulate matter (PM10), formaldehyde (HCHO), and total bacteria counts were monitored indoors and outdoors simultaneously. The average respirable particulate matter concentrations were higher than the HK Objective, and the maximum indoor PM10 level exceeded 1000 microg/m3. Indoor CO2 concentrations often exceeded 1000 microl/l in air-conditioning and ceiling fan classrooms, indicating inadequate ventilation. Maximum indoor CO2 level reached 5900 microl/l during class at the classroom with cooling tower ventilation. Increasing the rate of ventilation or implementation of breaks between classes is recommended to alleviate the high CO2 level. Other pollution parameters measured in this study complied with the standards. The two most important classroom air quality problems in Hong Kong were PM10 and CO2 levels.

Air Pollution↗
PubMed2000

Constituents of red yeast rice, a traditional Chinese food and medicine.

Detailed analyses were undertaken of the natural constituents of red yeast rice, a traditional Chinese medicine and food known for centuries to improve blood circulation. Preparation of red yeast rice following ancient methods by fermenting the fungal strain Monascus purpureus Went on moist and sterile rice indicated the presence of a group of metabolites belonging to the monacolin family of polyketides, together with fatty acids, and trace elements. The presence of these compounds may explain in part the cholesterol-lowering ability associated with this traditional Chinese food.

Anticholesteremic Agents↗
PubMed2000

A pilot study of systemic corticosteroid administration in conjunction with intrapleural adenoviral vector administration in patients with malignant pleural mesothelioma.

One of the primary limitations of adenoviral (Ad) -mediated gene therapy is the generation of anti-Ad inflammatory responses that can induce clinical toxicity and impair gene transfer efficacy. The effects of immunosuppression on these inflammatory responses, transgene expression, and toxicity have not yet been systematically examined in humans undergoing Ad-based gene therapy trials. We therefore conducted a pilot study investigating the use of systemic corticosteroids to mitigate antivector immune responses. In a previous phase I clinical trial, we demonstrated that Ad-mediated intrapleural delivery of the herpes simplex virus thymidine kinase gene (HSVtk) to patients with mesothelioma resulted in significant, but relatively superficial, HSVtk gene transfer and marked anti-Ad humoral and cellular immune responses. When a similar group of patients was treated with Ad.HSVtk and a brief course of corticosteroids, decreased clinical inflammatory responses were seen, but there was no demonstrable inhibition of anti -Ad antibody production or Ad-induced peripheral blood mononuclear cell activation. Corticosteroid administration also had no apparent effect on the presence of intratumoral gene transfer. Although limited by the small numbers of patients studied, our data suggest that systemic administration of steroids in the context of Ad-based gene delivery may limit acute clinical toxicity, but may not inhibit cellular and humoral responses to Ad vectors.

Adenoviridae↗