Expressions of TGF-ß1 and Eâ ¢A-FN after Rat Skeletal Muscle Contusion and Wound Age Estimation.

ABSTRACT: Objective To study the expressions of transforming growth factor-ß1 （TGF-ß1） and EⅢA-fibronectin （EⅢA-FN） at different time points of antemortem injury, antemortem injury postmortem expression and postmortem injury and to explore their application value in wound age estimation. Methods A model of rat skeletal muscle contusion was established. The rats were randomly divided into normal control group （n=5）, antemortem contusion group （n=40）, antemortem contusion postmortem expression group （n=110） and postmortem injury group （n=25）. The expressions of TGF-ß1 and EⅢA-FN after rat skeletal muscles antemortem contusion were detected with immunohistochemical staining. Expression changes of TGF-ß1 and EⅢA-FN mRNA in each group were analyzed with real-time fluorescence quantitative PCR. Results Immunohistochemical staining results showed that a large number of polymorphonuclear leukocyte, mononuclear cells and fibroblastic cells showed a strong expression of TGF-ß1 in wounded zones 12 h-14 d after antemortem contusion. EⅢA-FN was mainly distributed in the extracellular matrix, 3 to 7 d post-traumatic. Real-time fluorescence quantitative PCR results showed that TGF-ß1 and EⅢA-FN mRNA in antemortem injury group reached the peak at 3 and 5 d post-traumatic respectively. The expressions of TGF-ß1 and EⅢA-FN mRNA in antemortem contusion postmortem expression group peaked at 6 h and 12 h postmortem. The expression of TGF-ß1 and EⅢA-FN mRNA in postmortem injury group 0.5-12 h postmortem was significantly lower than those of the normal control group and the antemortem contusion group. Conclusion TGF-ß1 and EⅢA-FN might become a reference index for skeletal muscle wound age estimation.

Research Advances in Sympathetic Remodeling after Myocardial Infarction and Its Significance in Forensic Science.

Sympathetic remodeling after myocardial infarction is presented as denervation, sympathetic nerve sprouting and sympathetic hyperinnervation, and is closely related to ventricular tachyarrhythmias and even sudden cardiac death at convalescence in patients with myocardial infarction. This article reviews the anatomic structure, morphology and functional remodeling of cardiac sympathetic nerve, as well as its role in healed myocardial infarction identification, which may provide references for forensic research.

[Comparison of the Skin and Skeletal Muscle Contusion in Rats Induced by Blunt Force with Different Heights].

OBJECTIVES: To explore the differences in the repair process of skin and skeletal muscle after contusion caused by blunt force attack with different heights. METHODS: Three degrees of contusion were performed on SD rats' right hind limbs by a designed free-dropping device falling from 15, 30 and 50 cm heights, which as a main consideration factor for degree of injury. The repair process of skin and skeletal muscle at 6 h, 24 h, 3 d, 7 d and 13 d after contusion were observed using routine histological methods. RESULTS: Hematoma within skin and/or muscle was found in the rats' hind limbs after contusion with three different heights. The repair processes were similar at 24 h after contusion. However, with the increase of height, the display degree was more obvious. At 3 d after contusion, the RBC of the hemorrhagic region would be decomposed and elapsed in 15 cm contusion group, but for 30 cm contusion group, it delayed to 7 d. At 13 d after contusion, the similar result was found in 15 cm and 30 cm contusion groups, in contrast, the 50 cm contusion group was still in the proliferative phase. CONCLUSIONS: With the increase of height, the occurring rate of hematoma within skin and muscle at the same time increases, and the more serious histological appearance after contusion, including inflammation and proliferation, the longer healing process are observed. According to the results of present study and considering forensic application, the contusion model with 50 cm height （2.58 J/cm²ï¼‰ is recommended as the experimental animal model for the future study of wound age estimation on contusion.

Household gas cooking: a risk factor for respiratory illnesses in preschool children.

AIMS: To explore the association of household gas cooking and respiratory illnesses in preschool children and their relation to outdoor air pollution. METHODS: Cross-sectional study among households that used gas stoves for cooking in two housing estates with contrasting air qualities in Hong Kong. A structured questionnaire was administered to parents of 426 children aged 0-6 years on their exposure to gas cooking and passive smoking, and the prevalence of respiratory illnesses. RESULTS: A total of 111 children (26.1%) were reported to have one or more respiratory illnesses (allergic rhinitis, asthma, bronchitis, sinusitis, and pneumonia). Of these, 21 (18.9%), 41 (36.9%), and 49 (44.1%) children were from households that cooked once, twice, and three times a day with gas. Hierarchical logistic regression models adjusting for socioeconomic, demographic, and indoor risk factors including passive smoking showed that household gas cooking was positively associated with respiratory illnesses. There was a dose-response relation between the frequency of gas cooking and the prevalence of respiratory illnesses in the estate with lower outdoor air pollution (OR = 6.1 and 3.2 respectively, for cooking three and two meals a day, compared to one meal a day). This relation was not observed in the more polluted estate. The association between the presence of a cigarette smoker in the household and the prevalence of respiratory illnesses was not significant. CONCLUSIONS: As gas cooking is common in urban households, the findings could have important public health implications.

Agreement between hearing thresholds measured in non-soundproof work environments and a soundproof booth.

AIMS: To study the agreement between audiometric test results measured in non-soundproof environments at the worksite, and in a soundproof booth. METHODS: In a cross sectional prevalence study on noise induced hearing loss, 885 transport workers whose hearing thresholds were measured by a standard audiometric test method in non-soundproof environments at the worksite were identified to have some hearing loss (>25 dB), and were retested in a soundproof booth. RESULTS: At 4-8 KHz, the mean of the absolute differences in hearing threshold obtained by these two methods was 2 dB or less. When the proportions of hearing loss (> or =30 dB for any frequencies at 3-8 KHz, or > or =90 dB for three low frequencies at 0.5-2 KHz, or > or =90 dB for three high frequencies at 3-6 KHz) were compared, considerable differences existed. A much better agreement was obtained when the criteria for hearing loss as measured in the field test under non-soundproof conditions were relaxed by 5 dB. At 4 KHz, the difference between the proportion of subjects with hearing loss as measured in the field and that as measured in the booth was the smallest. The kappa statistic was highest at 3 and 4 KHz. CONCLUSIONS: Audiometric test results conducted in non-soundproof environments in the field are comparable to those obtained in a soundproof environment among transport workers with a hearing loss of >25 dB. The hearing threshold at 4 KHz appears suitable for the estimation of the prevalence of hearing loss when appropriate adjustments are made in the diagnostic criteria.

Assessing the provision of occupational health services in the construction industry in Hong Kong.

A survey was conducted to review the provision of occupational health services (OHS) in the construction industry, the most hazardous industry in Hong Kong. A questionnaire was used to collect information on various aspects of OHS from a sample of construction companies. OHS provision was estimated by an overall score, with the various components weighted for their importance regarding prevention. Factors affecting the provision of services were explored by multiple linear regressions. Only 58 of the 183 establishments (32%) performed environmental assessment; 37 (20%) offered medical examinations to their workers and 70 (38%) provided health and safety talks. Scores for the provision of OHS were generally low, especially for the component of surveillance concerning workers' health. In general, larger establishment size and having safety and/or health policies were the important factors leading to high scores.

Associations between daily mortalities from respiratory and cardiovascular diseases and air pollution in Hong Kong, China.

OBJECTIVE: To investigate the association between ambient concentrations of air pollutants and respiratory and cardiovascular mortalities in Hong Kong. METHODS: Retrospective ecological study. A Poisson regression of concentrations of daily air pollutants on daily mortalities for respiratory and cardiovascular diseases in Hong Kong from 1995 to the end of 1998 was performed using the air pollution and health: the European approach (APHEA) protocol. The effects of time trend, seasonal variations, temperature, and humidity were adjusted. Autocorrelation and overdispersion were corrected. Daily concentrations of nitrogen dioxide (NO2), sulphur dioxide (SO2), ozone (O3), and particulate matter <10 microm in aerodynamic diameter (PM10) were averaged from eight monitoring stations in Hong Kong. Relative risks (RRs) of respiratory and cardiovascular mortalities (per 10 microg/m(3) increase in air pollutant concentration) were calculated. RESULTS: Significant associations were found between mortalities for all respiratory diseases and ischaemic heart diseases (IHD) and the concentrations of all pollutants when analysed singly. The RRs for all respiratory mortalities (for a 10 microg/m(3) increase in the concentration of a pollutant) ranged from 1.008 (for PM10) to 1.015 (for SO2) and were higher for chronic obstructive pulmonary diseases (COPD) with all pollutants except SO2, ranging from 1.017 (for PM10) to 1.034 (for O3). RRs for IHD ranged from 1.009 (for O3) to 1.028 (for SO2). In a multipollutant model, O3 and SO2 were significantly associated with all respiratory mortalities, whereas NO2 was associated with mortality from IHD. No interactions were detected between any of the pollutants or with the winter season. A dose-response effect was evident for all air pollutants. Harvesting was not found in the short term. CONCLUSIONS: Mortality risks were detected at current ambient concentrations of air pollutants. The associations with the particulates and some gaseous pollutants when analysed singly were consistent with many reported in temperate countries. PM10 was not associated with respiratory or cardiovascular mortalities in multipollutant analyses.

Chloroplast protein translocon components atToc159 and atToc33 are not essential for chloroplast biogenesis in guard cells and root cells.

Protein import into chloroplasts is mediated by a protein import apparatus located in the chloroplast envelope. Previous results indicate that there may be multiple import complexes in Arabidopsis. To gain further insight into the nature of this multiplicity, we analyzed the Arabidopsis ppi1 and ppi2 mutants, which are null mutants of the atToc33 and atToc159 translocon proteins, respectively. In the ppi2 mutant, in contrast to the extremely defective plastids in mesophyll cells, chloroplasts in guard cells still contained starch granules and thylakoid membranes. The morphology of root plastids in both mutants was similar to that in wild type. After prolonged light treatments, root plastids of both mutants and the wild type differentiated into chloroplasts. Enzymatic assays indicated that the activity of a plastid enzyme was reduced only in leaves but not in roots. These results indicated that both the ppi1 and ppi2 mutants had functional root and guard cell plastids. Therefore, we propose that import complexes are cell type specific rather than substrate or plastid specific.

The Arabidopsis sex1 mutant is defective in the R1 protein, a general regulator of starch degradation in plants, and not in the chloroplast hexose transporter.

Starch is the major storage carbohydrate in higher plants and of considerable importance for the human diet and for numerous technical applications. In addition, starch can be accumulated transiently in chloroplasts as a temporary deposit of carbohydrates during ongoing photosynthesis. This transitory starch has to be mobilized during the subsequent dark period. Mutants defective in starch mobilization are characterized by high starch contents in leaves after prolonged periods of darkness and therefore are termed starch excess (sex) mutants. Here we describe the molecular characterization of the Arabidopsis sex1 mutant that has been proposed to be defective in the export of glucose resulting from hydrolytic starch breakdown. The mutated gene in sex1 was cloned using a map-based cloning approach. By complementation of the mutant, immunological analysis, and analysis of starch phosphorylation, we show that sex1 is defective in the Arabidopsis homolog of the R1 protein and not in the hexose transporter. We propose that the SEX1 protein (R1) functions as an overall regulator of starch mobilization by controlling the phosphate content of starch.

Computer simulation of particle overlap in fiber count samples.

Fibrous aerosols are of great importance to industrial hygienists because of the severe health risks that may be associated with inhaling such particles. Previous studies on measurement error due to overloading of fibers and nonfibrous particles on the collected sample indicate that a 100-1300 fiber/mm2 filter area is the best filter loading density to reduce bias in fiber counts. The present study investigated the upper fiber and particle concentration limits for reliable counting and identification and the possibility of a procedure for correcting observed fiber counts to account for fiber masking due to overlapping particles or fibers. A computer-generated grid was used to simulate the light microscope graticule field. The resolution of 2000 x 2000 was found to accurately represent the shape of the fibers and nonfibrous particles. Bivariate lognormal distributions were used to describe the length and width distributions of the fibers. The capability of distinguishing particle-overlapped fibers (defined as the resolution index), the coverage of the graticule field, the filter surface loading density, size distributions of fibers and particles, and the fiber-to-particle concentration ratio were the primary parameters in this study. The counting efficiency was found to consistently decrease with increasing filter surface loading density and decreasing resolution index. The recommended upper limit of filter surface fiber density depended not only on the number concentration ratio but also on the filter surface loading densities and size distributions of fibers and particles. The advantage of using a thoracic preseparator on counting efficiency was calculated and found to improve counting efficiency significantly when the count median diameter of nonfibrous particles was close to or larger than the thoracic 50% cutoff point of 10 microm.

Adverse effects of low-level air pollution on the respiratory health of schoolchildren in Hong Kong.

To evaluate the respiratory effects of long-term exposure to air pollution, schoolchildren (ages 8 to 12 years) from two districts in Hong Kong with contrasting air quality were studied. Parents of 1660 children completed questionnaires on respiratory symptoms, and 1294 children had their ventilatory function tested with a spirometer. After adjustment for relevant covariates, children living in the more polluted district had increased odds ratios for frequent cough (1.74), frequent sputum (1.87), chronic sputum (1.84), and doctor-diagnosed asthma (1.98). Children of both sexes in the more polluted district had significantly poorer lung function, and the differences among girls were more marked. The study provides additional evidence for the adverse effects of long-term exposure to relatively low-level air pollution.

Changes in the gene expression of GABA(A) receptor alpha1 and alpha2 subunits and metabotropic glutamate receptor 5 in the basal ganglia of the rats with unilateral 6-hydroxydopamine lesion and embryonic mesencephalic grafts.

By using an animal model of parkinsonism, we examined the expression of GABA(A) receptor (R) and metabotropic glutamate receptor (mGluR) 5 in the basal ganglia after transplantation with dopamine-rich tissue. The adult rats were unilaterally lesioned by the injection of 6-hydroxydopamine to their left medial forebrain bundles. At 5-10 weeks following the dopaminergic denervation, the levels of GABA(A)R in the left caudate-putamen and globus pallidus were about 20 and 16% lower than that of the right intact (control) sides, as shown by [3H]flunitrazepam binding autoradiography on the brain sections. However, the receptor density increased to around 132 and 130% of control levels in the entopeduncular nucleus and substantia nigra pars reticulata of the lesioned sides. Furthermore, in situ hybridization analysis exhibited parallel trends of changes in the levels of the GABA(A)R alpha1 and alpha2 subunit and mGluR5 mRNAs in the neurons of the brain regions with that of the proteins detected by the binding assay. A number of the rats 5 weeks postlesion were transplanted with the ventral mesencephalon of the embryonic rat into their left striata. Five weeks later, the changes in the [3H]flunitrazepam binding seemed to be recovered by approximately 50-63% on the grafted sides of the areas. Moreover, the transplantation appeared to produce a nearly complete reversal of the lesion-induced alterations in the levels of the mRNAs. Thus, the data indicate the mechanism of gene regulation for the modified expression of the receptors and could implicate the participation of the receptors in the pathogenesis of Parkinson's disease.

Predicted maximal oxygen uptake in normal Hong Kong Chinese schoolchildren and those with respiratory diseases.

To assess the maximum oxygen uptake (V'O2 max) of Hong Kong Chinese children and to explore its association with respiratory illnesses, we conducted the Multistage Fitness Test (MFT), a 20-m shuttle run test, in 1,427 schoolchildren aged between 8-12 years. Information on respiratory symptoms in the previous year, cumulative respiratory illnesses, and habitual physical activities were collected. Spirometry was carried out to derive forced expiratory volume in 1 sec (FEV1). The V'O2max was 30.3 mL x kg( - 1) x min( - 1) for boys, and 28.6-mL x kg( - 1) x min( - 1) for girls; these values were low by Western standards. V'O2max was significantly reduced in children with asthma ( - 1.3 mL x kg( - 1) x min( - 1)) and bronchitis ( - 0.7.mL x kg( - 1) x min( - 1)) when adjusted for other covariates. A significant decrease in FEV1 was also observed in these children. The correlation between V'O2max and FEV1 was significant but weak. Habitual physical activity was an independent predictor of V'O2max, but not of FEV1. The low V'O2 max in Hong Kong children may be explained in part by ethnic differences and possibly a low level of physical activity.

Characteristics of workers attending the pneumoconiosis clinic for silicosis assessment in Hong Kong: retrospective study.

OBJECTIVE: To describe and analyse the baseline characteristics of workers attending the pneumoconiosis clinic for assessment of silicosis. DESIGN: Retrospective cross-sectional study. SETTING: Outpatient clinic. PATIENTS: One thousand and fifty-six patients with silica dust exposure attending the pneumoconiosis clinic for compensation assessment. MAIN OUTCOME MEASURES: Baseline demographic characteristics, lung function parameters, and radiographic findings. RESULTS: Six hundred and forty-eight patients were diagnosed with silicosis, of which 10 were female. Excluding the data on female patients, the mean duration of dust exposure was 24.2 years. The majority of patients were involved in caisson work and stone splitting. Most newly diagnosed patients had simple silicosis. Less than a quarter (24.8%) had progressive massive fibrosis. Lung function parameters at diagnosis were within the normal range. Pulmonary tuberculosis remained an important co-existing disease. CONCLUSION: The major cause of silicosis in Hong Kong is chronic silica dust exposure in the construction industry. Simple silicosis predominated at diagnosis, with normal lung function parameters seen in the majority of patients.

Recent trends of stroke mortality in Hong Kong: age, period, cohort analyses and the implications.

This study describes the time trend of cerebrovascular disease (CVD) mortality during the period 1976-1995 in Hong Kong and explores the period and birth cohort effects using Poisson regression models with correction for overdispersion of data. A clear downward trend was observed for age-adjusted CVD mortality rate in both sexes. It decreased from 84 per 100,000 to 41 per 100,000 among men (a 51% drop), and from 56 per 100,000 to 35 per 100,000 among women (a 38% drop). The rate of decline was in general greater in the second decade and among males, resulting in a significant downward trend for the male-to-female rate ratio. Both the period of death and the birth cohort showed a significant effect on the reduction in mortality rates, but the latter seemed to have a more substantial influence. However, an increasing trend was observed among younger males in the second decade, and the protective cohort effect seemed to be waning for the more recent cohorts in both sexes. Closer monitoring of the situation in the next years is warranted.

Mutation of Arabidopsis plastid phosphoglucose isomerase affects leaf starch synthesis and floral initiation.

We isolated pgi1-1, an Arabidopsis mutant with a decreased plastid phospho-glucose (Glc) isomerase activity. While pgi1-1 mutant has a deficiency in leaf starch synthesis, it accumulates starch in root cap cells. It has been shown that a plastid transporter for hexose phosphate transports cytosolic Glc-6-P into plastids and expresses restricted mainly to the heterotrophic tissues. The decreased starch content in leaves of the pgi1-1 mutant indicates that cytosolic Glc-6-P cannot be efficiently transported into chloroplasts to complement the mutant's deficiency in chloroplastic phospho-Glc isomerase activity for starch synthesis. We cloned the Arabidopsis PGI1 gene and showed that it encodes the plastid phospho-Glc isomerase. The pgi1-1 allele was found to have a single nucleotide substitution, causing a Ser to Phe transition. While the flowering times of the Arabidopsis starch-deficient mutants pgi1, pgm1, and adg1 were similar to that of the wild type under long-day conditions, it was significantly delayed under short-day conditions. The pleiotropic phenotype of late flowering conferred by these starch metabolic mutations suggests that carbohydrate metabolism plays an important role in floral initiation.

Lung cancer mortality among a cohort of men in a silicotic register.

To examine any association between silicosis and lung cancer, the clinic records of a cohort of 1502 silicotic workers diagnosed after 1981 were reviewed. All of the essential data, including occupational exposure, smoking habits, radiographic extent of silicosis, and vital status of each subject, were noted. The standardized mortality ratio for various causes of death was calculated. Thirty-three patients died from lung cancer, giving a standardized mortality ratio of 1.94 (95% confidence interval, 1.35 to 2.70). However, smoking accounted for most of the excess of lung cancer deaths among the silicotic workers in the cohort, and no consistent relationship between lung cancer mortality risk and either duration of exposure to silica dust or severity of silicosis was observed. There is no conclusive evidence in our data to support the hypothesis that lung cancer may be associated with silicosis.