Brown Trout and European Minnow as Target Species for Genotoxicity Tests: Differential Sensitivity to Heavy Metals

Brown trout (Salmo trutta) and European minnow (Phoxinus phoxinus) were evaluated as target species to carry out genotoxicity tests. Assessment was made of their relative abundance in wild; their distribution areas; and their sensitivity to heavy metals, intraperitoneally exposing individuals of both species to a low dose (1.7 mg/kg body weight) of different heavy metals. Micronuclei were scored in renal erythrocytes 24 h after treatment. Cadmium chloride significantly induced micronuclei in both species whereas mercury nitrate induced micronuclei increase only in brown trout. Brown trout is abundant, present in all studied freshwater ecosystems, and more sensitive to toxic heavy metals than minnow; therefore it is presented as a target species for studies on heavy metal genotoxicity.     

Lead in New-Fallen Snow

In a mountainous area of Yugoslavia, where a lead mine and smelter have been in operation for some 300 years, samples of new-fallen snow were obtained within three zones situated at increasing distances in different directions from the two centrally located stacks of the smelter, and were analyzed for their lead content. The lead content of new snow would be a factor of the quantities of lead in the air through which precipitation of moisture has occurred. The results confirmed the expectation that, with increasing distance from the source of lead emission, the snow contained consistently decreasing quantities of lead. Moreover, samples of new-fallen snow collected at altitudes that differed from that of the stacks yielded results that deviated from each other to such an extent as to alter significantly the negative correlation of the results with an increasing distance of the sampling sites from the stacks.     

锥形束CT研究3种根管治疗方式的根管封闭效果

目的应用锥形束CT定量评价目前临床上常用的3种根管治疗方式的根管封闭效果,为临床上有针对性地选择根管治疗方式提供理论依据。方法选45颗拔除的单根管前牙及前磨牙,随机分成3组,分别采用NiTi K锉预备,侧方加压充填根管治疗法(A组);机用ProTaper预备,侧方加压充填根管治疗法(B组);机用ProTaper预备,连续波热垂直加压技术充填根管治疗法(C组)。使用锥形束CT分别对根管预备后及充填后牙体进行扫描,获得根管总的封闭容量百分比(the percentage of obturated volume,POV),根管根尖1/3、中1/3及冠1/3的封闭容量百分比。比较3组的封闭效果,对数据进行WilconxonMann-Whitney U检验分析。结果 A、B组比较,无论总POV,根管根尖1/3、中1/3还是冠1/3的POV,2组之间比较均无明显统计学差异(P>0.05)。C组总POV,根管根尖1/3、中1/3及冠1/3的POV均明显高于其他2组(P<0.05)。结论对于使用相同的根管充填方式(侧方加压充填)充填根管,其最终的根管封闭效果并不受根管预备方式的影响。机用ProTaper预备,连续波热垂直加压技术充填根管治疗组的根管封闭性最佳。     

Statutory and voluntary sector palliative care in the community setting: National Health Service professionals' perceptions of the interface

Following the rapid service development brought about by the hospice movement, specialist palliative care services are involved with up to 50% of all patients dying with cancer in the United Kingdom, although the primary health care team remains the main provider of community based palliative care. This paper discusses findings from a survey of palliative care provision in the south west of England, and describes the perceptions of the primary care team (general practitioners and district nurses) about the interface between themselves and voluntary sector specialist palliative care providers (hospice in-patient units, hospice home care nurses and other charitably funded specialist palliative care nurses). The voluntary sector services are run with a mixture of funding from charitable sources (public donations, legacies, charitable trust moneys), and statutory funding (grants and recurrent contracts from central government, district health commissions, and local health care trusts). The interview and questionnaire data suggest that the voluntary sector services are perceived variably as substituting, supplementing, complementing and duplicating the services provided by the primary care team. Drawing attention to these dimensions and the ambivalence sometimes felt by general practitioners and district nurses could provide a means of negotiating consensus on appropriate professional tasks and facilitating interprofessional practice in what is increasingly a mixed economy of statutory and voluntary funded health care.     

Maternal second trimester blood levels of selected heavy metals in pregnancies complicated with neural tube defects

Purpose: Neural tube defects (NTDs) are the most common malformations of the central nervous system (CNS). There is continuing research for the identification of risk factors and interventions for prevention of NTDs. The aim of this study was to investigate the maternal second trimester blood levels of selected heavy metals namely, arsenic (As), cadmium (Cd), mercury (Hg), manganese (Mn), nickel (Ni), and lead (Pb) and their possible relation with the occurrence of NTDs.

Methods: Twenty-one healthy second trimester pregnant women with fetuses affected with NTD (cases) were matched with 21 healthy pregnant women with unaffected fetuses (controls) with respect to age, body mass index (BMI), and gestational age. Maternal blood levels of heavy metals were measured after an overnight fasting period.

Results: No significant differences were observed in terms of maternal blood levels of As, Cd, Hg, and Ni between NTD-affected and unaffected pregnancies. The blood Pb and Mn levels were found to be higher in pregnant women with a fetus affected with NTD when compared with pregnant women with unaffected fetuses (for Pb, in cases 12.3?±?5.5?µg/L, in controls 7.8?±?2.4?µg/L; for Mn in cases 3.6?±?1.4?µg/L, in controls 2.4?±?1.0?µg/L, p?Conclusions: High maternal second trimester blood levels of Pb and Mn during pregnancy are associated with NTDs in the newborn.     

Heavy long-term ethanol consumption induces an alpha- to beta-myosin heavy chain isoform transition in rat

Alcoholic heart muscle disease is characterized by structural changes which include chamber dilation, ventricular hypertrophy, and myocyte damage. These effects often lead to contractile dysfunction and ultimately to heart failure if alcohol consumption is not terminated. In rat models for heart failure in which heart failure is induced by pressure or volume overload, there is a shift in the myosin heavy chain (MHC) isoforms, from α to β. As a result of this MHC transition, there is typically a decrease in myosin ATPase activity. We utilized a rat model of chronic alcohol consumption in order to determine if alcohol causes a similar shift in MHC isoforms and changes in myosin ATPase activity. A liquid diet containing 9% ethanol (46% of daily calories; 11.8 g/kg/day) was administered to adult rats for a period of 60 or 90 days. This heavy consumption of ethanol resulted in an average blood ethanol content of 150 mg%. The relative abundance of β-MHC isoform protein increased from a control level of 9.7% to 35.1% in hearts of ethanol-fed rats, following 90 days of ethanol consumption. In a separate set of experiments, the levels of α-MHC and β-MHC mRNA were demonstrated to increase by 150% and 230%, respectively. Following a 60 day treatment, there was a significant reduction in the actomyosin Mg²⁺-ATPase activity in the myofibrillar preparations from hearts of ethanol-fed rats compared to hearts from control-fed rats. In addition, the myosin Ca²⁺-ATPase activity was decreased 17% and 30% after 60 and 90 days of ethanol consumption, respectively. The present study demonstrates that chronic ethanol consumption induces an increase in the proportion of the total MHC content composed of the β-isoform. This isoform transition is accompanied by an accumulation of β-MHC mRNA, suggesting that the switch is organized pretranslationally. A functional consequence of this transition in MHC phenotype is demonstrated by significant decreases in the myofibrillar and myosin ATPase activities. Received: 17 November 1998, Returned for 1. revision: 4 January 1999, 1. Revision received: 22 March 1999, Returned for 2. Revision: 12 April 1999, 2. Revision received: 31 May, Accepted: 31 May 1999     

Micronuclei and cell survival in human liver cancer cells irradiated by 25MeV/u (40)Ar14(+)

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Evaluation of B-cell clonality in archival skin biopsy samples of cutaneous B-cell lymphoma by immunoglobulin heavy chain gene polymerase chain reaction

Polymerase chain reaction (PCR)-based detection of clonal T- and B-cells is widely used in the diagnosis of various lymphomas, including those of the skin. A large number of corresponding methods have been published. Recently, for the first time, standardized PCR protocols were developed in common by 14 European centers of lymphoma diagnosis and research (Biomed-2 protocols). Here, we have applied Biomed-2 immunoglobulin heavy chain (IgH)-PCR for clonality detection in primary cutaneous B-cell lymphoma (CBCL) and compared it with previously established methods. The DNA of 43 paraffin-embedded lesional skin biopsies of confirmed CBCL cases [27 follicle center cell lymphoma (FCCL), 11 marginal zone B-cell lymphoma/immunocytoma (MZL/IC) and five large CBCL of the lower leg (CBCL-LL)] were amplified by the Biomed-2 IgH-PCR protocols as well as using four other assays, priming also the three IgH framework regions (FR) 1-3. All PCR products were analysed by fluorescence fragment analysis. Twenty-nine of 43 (67%) CBCL samples (5/5, 100% of CBCL-LL; six of 11, 54.5% of IC/MZL; 18 of 27, 66.7% of FCCL) showed monoclonal B-cell presence complementary in all of the IgH-PCR. The three Biomed-2 PCR indicated together clonality in 24 of 43 samples (56%). Considering each method separately, the Biomed-2 FR3-PCR showed the highest rate of clonality detection (20 of 43, 47%). In conclusion, the Biomed-2 FR3-PCR is recommended for detecting B-cell clonality in archival skin samples of CBCL but should be completed by FR1- and/or FR2-PCR.