Occupational exposure and health problems in small-scale industry workers in Dar es Salaam, Tanzania: a situation analysis

BACKGROUND: Workers in informal small-scale industries (SSI) in developing countries involved in welding, spray painting, woodwork and metalwork are exposed to various hazards with consequent risk to health. Aim To assess occupational exposure and health problems in SSI in Dar es Salaam, Tanzania. METHODS: Focused group discussions (FGD) were conducted among SSI workers. Participants were assessed for exposure to occupational and environmental hazards, the use of protective equipment and health complaints by interview. The findings were discussed with participants and potential interventions identified. RESULTS: Three hundred and ten workers were interviewed (response rate 98%). There was a high level (>90%) of self-reported exposure to either dust, fumes, noise or sunlight in certain occupational groups. There was low reported use of personal protective equipment. There was a high level of self-reported occupational health problems, particularly amongst welders and metalworkers. Workers reported their needs as permanent workplaces, information on work related hazards, water and sanitation, and legislation for SSI. CONCLUSIONS: In SSI in Tanzania, our study suggests that workers have high levels of exposure to multiple health hazards and that use of protective equipment is poor. This group of workers warrants improved occupational health and safety provision.     

Molecular multiple endpoint embryonic stem cell test--a possible approach to test for the teratogenic potential of compounds

The embryonic stem cell test (EST) examines the cytotoxicity of chemical compounds on embryonic stem (ES) cells and 3T3.A31 fibroblasts. Additionally, the EST measures the ability of ES cells to differentiate into contracting cardiomyocytes following drug exposure. In this study, we introduce new endpoints to obtain a molecular multiple endpoint EST (mme-EST), enabling the identification of potential chemical effects on osteogenic, chondrogenic and neural differentiation in addition to the traditional endpoint of cardiomyocyte differentiation. Six compounds in three classes with known teratogenic in vivo potential were assayed with the mme-EST in a pilot study: penicillin G (non-teratogenic), 5-fluorouracil and retinoic acid (strongly teratogenic), diphenylhydantoin, valproic acid and thalidomide (moderately teratogenic). While the traditional EST measures a morphological endpoint, we included molecular markers of differentiation as endpoints. With the mme-EST, every compound could be classified correctly according to its known teratogenic potential in vivo. Penicillin G, 5-fluorouracil and diphenylhydantoin inhibited differentiation of all endpoints equally. Interestingly, valproic acid showed the strongest inhibition of neural differentiation, while thalidomide specifically inhibited osteogenic development. Retinoic acid, on the other hand, supported neural but inhibited chondrogenic and osteogenic differentiation concentration-dependently. Valproic acid and thalidomide, classified incorrectly with the established EST model, were classified correctly with the mme-EST according to their effects on specific endpoints. This pilot study indicates that the predictive value of the EST may be enhanced by including further differentiation endpoints.     

Physiological and genetic responses of European eel (Anguilla anguilla L.) to short-term chromium or copper exposure-Influence of preexposure to a PAH-like compound

Anguilla anguilla L. (European eel) was exposed for 24 h to chromium (Cr-100 microM and 1 mM) or copper (Cu-1 and 2.5 microM), with or without a 24-h preexposure to beta-naphthoflavone (BNF-2.7 microM), a polycyclic aromatic hydrocarbon (PAH)-like compound, simulating sequential exposure to PAHs and heavy metals. Plasma cortisol, thyroid-stimulating hormone (TSH), free triiodothyronine (T3), and free thyroxine (T4) were determined in order to assess the effects on endocrine function. Plasma glucose and lactate also were measured. The frequency of erythrocytic nuclear abnormalities (ENA) was scored as a genotoxicity indicator. Plasma T4 decreased in eels when exposed to Cr only. The interference of BNF preexposure on Cr effects was observed as a significant plasma glucose increase. Single exposures to Cu elevated plasma cortisol and glucose (2.5 microM), as well as plasma lactate (1 microM), whereas a T4 decrease was found for both concentrations. BNF preexposure prevented plasma cortisol and lactate increases; however, a greater T4 decrease was observed in eels exposed to 2.5 microM Cu. Moreover, this pretreatment was crucial for genotoxicity expression because only BNF+2.5 microM Cu-exposed fish exhibited significant ENA induction. In general, plasma T4 was the most affected hormone, as it responded to all Cr and Cu exposure conditions.     

Fibre-type composition of rabbit jaw muscles is related to their daily activity

Skeletal muscles contain a mixture of fibres with different contractile properties, such as maximum force, contraction velocity and fatigability. Muscles adapt to altered functional demands, for example, by changing their fibre-type composition. This fibre-type composition can be changed by the frequency, duration and presumably the intensity of activation. The aim of this study was to analyse the relationship between the spontaneous daily muscle activation and fibre-type composition in rabbit jaw muscles. Using radio-telemetry combined with electromyography, the daily activity of five jaw muscles was characterized in terms of the total duration of muscle activity (duty time) and the number of activity bursts. Fibre-type composition of the muscles was classified by analysing the myosin heavy chain content of the fibres. The amount of slow-type fibres was positively correlated to the duty time and the number of bursts only for activations exceeding 20-30% of the maximum activity per day. Furthermore, cross-sectional areas of the slow-type fibres were positively correlated to the duty time for activations exceeding 30% of the maximum activity. The present data indicate that the amount of activation above a threshold (> 30% peak activity) is important for determining the fibre-type composition and cross-sectional area of slow-type fibres of a muscle. Activation above this threshold occurred only around 2% of the time in the jaw muscles, suggesting that contractile properties of muscle fibres are maintained by a relatively small number of powerful contractions per day.     

Loss of myostatin expression alters fiber-type distribution and expression of myosin heavy chain isoforms in slow- and fast-type skeletal muscle

Myostatin (Mstn) is a member of the transforming growth factor-beta family that negatively regulates skeletal muscle mass. Mstn knockout mice have greater skeletal muscle mass than wild-type littermates. We investigated the effect of Mstn on fiber type by comparing adult muscles from the murine Mstn knockout with wild-type controls. Based on myofibrillar ATPase staining, the soleus of Mstn knockout mice displays a larger proportion of fast type II fibers and a reduced proportion of slow type I fibers compared with wild-type animals. Based on staining for succinate dehydrogenase (SDH) activity, a larger proportion of glycolytic fibers and a reduced proportion of oxidative fibers occur in the extensor digitorum longus (EDL) of Mstn knockouts. These differences in distribution of fiber types are accompanied by differences in the expression of myosin heavy chain (MHC) isoforms. In both Mstn knockout soleus and EDL, larger numbers of faster MHC isoforms are expressed at the expense of slower isoforms when compared with wild-type littermates. Thus, the absence of Mstn in the knockout mouse leads to an overall faster and more glycolytic muscle phenotype. This muscle phenotype is likely a consequence of developmental processes, and inhibition of Mstn in adults does not cause a transformation to a more fast and glycolytic phenotype. Our findings suggest that myostatin has a critical role in regulating the formation, proliferation, or differentiation of fetal myoblasts and postnatal fibers.     

Changes in cerebral oxygenation during cold (28 degrees C) and warm (34 degrees C) cardiopulmonary bypass using different blood gas strategies (alpha-stat and pH-stat) in patients undergoing coronary artery bypass graft surgery

BACKGROUND: Impaired cerebral oxygenation, which is reflected by measuring jugular bulb oxygenation, is thought to play an important role in the development of neurological injury after cardiac operations with cardiopulmonary bypass (CPB). The effects of cardiopulmonary temperature and blood gas strategy on cerebral oxygenation are not fully appreciated. METHODS: Sixty patients were randomly allocated into four equal groups (cold alpha-stat, cold pH-stat, warm alpha-stat and warm pH-stat) to compare the effect of these perfusion strategies on cerebral oxygenation monitored by jugular bulb oximetry [jugular bulb oxygen saturation (SjO(2)) and arterial-jugular bulb oxygen content difference (AjDO(2))]. Jugular bulb oxygen saturation and AjDO(2) were measured before CPB, after 5, 20, 40 min on CPB, at start and end of rewarming, 5 min before the end of CPB and 10 min after CPB. Two-way analysis of variance was used to model the lowest SjO(2) and highest AjDO(2) during CPB, with CPB temperature and blood gas management as contributing factors. RESULTS: Significant changes in SjO(2) were only related to the type of blood gas management, with no significant difference between warm and cold CPB patients. In addition, during rewarming, desaturation (SjO(2) 相似文献   

Phase I/II clinical trials of carbon ion therapy for prostate cancer

BACKGROUND: Heavy ion beams possess high linear energy transfer components and a prominent Bragg peak in the human body, resulting in higher relative biological effectiveness and improved dose distribution. To establish heavy ion therapy techniques for the treatment of prostate cancer, phase I/II clinical trials were initiated. METHODS: For 96 patients with T1b-T3 prostate cancer, three carbon ion beams were used to irradiate the prostate and seminal vesicles (20 times/5 weeks) with or without endocrine therapy. Radiation dose was expressed in GyE which was initially thought to be equivalent to photon dose. Total dose was gradually increased from 54 to 72 GyE. RESULTS: Carbon ion therapy was completed in 20 cases of T1b/T1c/T2aN0M0 as monotherapy, in 8 cases of T2b/T3pN0M0 with neoadjuvant endocrine therapy, and in 68 cases of T2b/T3N0/pN1M0 with neoadjuvant and adjuvant endocrine therapy. Median observation period was 47 months. Grade 3 late radiation morbidity of rectum and/or bladder/urethra developed in one and five cases who received 66 and 72 GyE of radiation, respectively. After these adverse effects were observed, total dose was decreased to 66 GyE and the radiation field was coned down during the treatment course. At 5 years, overall, cause-specific, clinical recurrence-free, and biochemical recurrence-free survival rates were 87.7, 94.9, 90.0, and 82.6%, respectively. Local control was achieved in all patients except one patient who received 54 GyE of radiation. CONCLUSIONS: The therapeutic techniques of carbon ion therapy have been established for patients with prostate cancer. Carbon ion therapy may exert excellent effect to the tissues of prostate cancer.     

Energy Reserves and Metal-storage Granules in the Hepatopancreas of <Emphasis Type="Italic">Oniscus asellus</Emphasis> and <Emphasis Type="Italic">Porcellio scaber</Emphasis> (Isopoda) from a Metal Gradient at Avonmouth,UK

Isopods taken from populations of Onsicus asellusand Porcellio scaberfrom long-term polluted sites in the vicinity of metal smelting works at Avonmouth, South West England, and from a control site near Tübingen, South Germany, were examined for the frequency and size of metal-containing granules (spherites), lipid droplets and glycogen in their hepatopancreas. The number and size of spherites in the hepatopancreas of O. asellus increased with decreasing distance to the smelter, but such a trend was not found in P. scaber. A trend towards massive reduction in hepatopancreatic energy reserves (lipid, glycogen) with increasing soil metal pollution was observed for O. asellus while, in contrast, the lipid and glycogen content of P. scabermidgut gland cells was independent of the distance to the smelter. In view of previous reports on metal accumulation and biochemical responses to metal pollution, we propose that the two investigated isopod species, which form stable populations in the Avonmouth metal gradient, use different strategies to survive.     

1989-2001年格鲁吉亚的卫生改革及对中国的启示--经济转型国家卫生改革经验报告(一)

对格鲁吉亚1989—2001年的基本国情、主要卫生改革措施、医疗保险制度改革、公共卫生服务改革、以家庭医学为中心的社区卫生服务改革等情况进行了总结分析,希望能对中国卫生改革实践有所借鉴和启示。     

高盐食品及海水中痕量元素Pb,Ni检测方法的研究

目的:建立测定高盐食品及海水中Pb,Ni检测的新方法。方法:研究应用利用注射器中填装吸附剂对高盐食品的消解液及海水中(pH>5)浓缩后用石墨炉原子吸收光谱法直接测定样品中痕量铅和镍[1]。本方法利用物理和化学的吸附作用富集测试元素同时避免了高浓度盐对石墨炉原子吸收光谱法的干扰。结果:选定了最佳测量条件,该方法只用一次洗提吸附剂即可满足实验需要,其回收率在94% ~98% 之间,相对标准偏差RSD控制在2% 左右。Pb,Ni的最低检出限为0 .2μg/L。结论:本法简便、快速、准确,灵敏度和精密度高。适用于高盐食品及海水样品中痕量Pb,Ni的测定。