Gordura corporal, índice de massa corporal e intensidade da atividade física de acordo com transporte ativo e a prática esportiva em escolares. Um estudo transversal / Body fat, body mass index and physical activity intensity according to active transport and sports practice in schoolchildren. A cross-sectional study

Contexto: A obesidade infantil ocasiona diversas doenças e uma das formas para combatê-la é a atividade física, que exerce um papel fundamental. Objetivo: Comparar as diferentes intensidades da atividade física mensurada objetivamente de acordo com o transporte ativo, a prática de esportes e as atividades físicas estruturadas e seu impacto na gordura corporal e índice de massa corporal (IMC) em escolares. Desenho e local: Estudo transversal de amostra por critério de conveniência, realizado em São Caetano do Sul pelo Centro de Estudos do Laboratório de Aptidão Física de São Caetano do Sul (CELAFISCS). Métodos: Foram avaliadas um total de 584 crianças (277 meninos) que atenderam aos critérios de inclusão. A amostra foi dividida em grupos segundo o transporte (ativo e passivo) e a prática esportiva (sim e não). Para análise estatística foi utilizado o teste t Student e o teste U de Mann-Whitney. Para o ajuste das variáveis foi utilizada a análise de covariância (ANCOVA). Resultados: Os meninos demonstraram que, independentemente do tempo de transporte, há efeito do tipo do transporte sobre a atividade física (AF) durante a semana, de intensidade moderada, moderada-vigorosa, AF durante o final de semana de intensidade moderada, moderada-vigorosa e vigorosa. As meninas demonstraram efeito do tipo de transporte sobre a AF durante a semana na AF de intensidade moderada e de intensidade moderada-vigorosa. A gordura corporal e o IMC não apresentaram diferenças entre os grupos. As práticas esportivas não tiveram diferenças significativas em nenhuma das variáveis. Conclusões: O transporte ativo atingiu os níveis de intensidade moderada, moderada-vigorosa durante a semana, tanto no masculino como no feminino. No final de semana, além dessas, a intensidade vigorosa foi encontrada nos meninos.

Transporte ativo no trajeto escolar: uma revisão integrativa / Active transport at the school path: an integrative review

o transporte ativo pode ser uma oportunidade para desenvolver comportamentos mais saudáveis na vida das crianças e jovens. O presente estudo busca identificar barreiras e facilitadores desse comportamento, bem como suas interfaces com a saúde dos escolares por meio de revisão de literatura. Trata-se de uma revisão integrativa de literatura realizada nas bases eletrônicas BVS, Scielo e periódico Capes, utilizando os descritores mobilidade, transporte, deslocamento, ativo, sustentável, estudantes, escolares e trajeto escolar em português, inglês e espanhol. Foram incluídos estudos realizados nas Américas e publicados nos últimos cinco anos. Os 16 artigos selecionados foram desenvolvidos no Brasil, Canadá, México e Estados Unidos, sendo que a maioria deriva de pesquisas mais amplas. Os resultados indicam que a prevalência de transporte ativo no trajeto escolar variou entre 10% nos Estados Unidos e 76% no Brasil. Alguns facilitadores desse comportamento foram: pais que utilizam transporte ativo; expectativa dos pais; percepção dos pais sobre boa estrutura e segurança; crianças mais velhas, sem veículos, de grandes cidades, com menor satisfação familiar, com maior número de dias fisicamente ativos; ser homem; presença de adulto e clima. Algumas barreiras foram: distâncias; maior idade, nível de escolaridade da mãe e classe econômica; maior tempo de trabalho dos pais; posse de veículo; zona urbana; bullying; muita coisa para carregar, ausência de árvore, criminalidade; presença de animais vadios e ter etnia latina. A interface do transporte ativo no trajeto escolar com a saúde foi reportada com o nível de atividade física, obesidade/sobrepeso (saúde individual) e barreiras e facilitadores a esse tipo de deslocamento (saúde ambiental). Considerando que atitudes cultivadas na infância têm grandes chances de permanecer na vida adulta, o transporte ativo no trajeto escolar pode ser uma estratégia na criação de hábitos saudáveis e sustentáveis que contribuam para melhor qualidade de vida, desde que se considerem seus determinantes e condicionantes...(AU)

the active transport can be an opportunity to develop healthier beh av iors in t h e lives of children and young people. The present study seeks to identify barriers and facilitators of this behavior, as well as their interfaces with the students' health through a literature review. It is an integrative literature review carried out on the electronic databases BVS, Scielo and Capes periodical, using the descriptors of mobility, transport, displacement, active, sustainable, students, school and schoo l p ath in Po rtuguese, English and Spanish. Studies carried out in the Americas and published in the last five years were included. The 16 selected papers were developed in Brazil, Canada, Mexico and the United States, with most of them deriving from broader researches. The results obtained reveal t he p revalence of active transport in school path varied between 10% in the United States and 76% in Brazil. Some facilitators of this behavior were: parents or adults who use active transport; parental expectation; parents' perception of good structure and safety; older children, without vehicles, large cities, with less family satisfaction, with more days of physical activities; be a man; adult presence and climate. Some barriers were: dist an ces; older age, mother's education level and economic class; longer working time for parents; vehicle ownership; urban area; bullying; a lot to carry, few trees, crime; presence of stray anim als and having Latin ethnicity. The interface between active transport in the school path and health was rep o rted as the level of hysical activity, obesity/overweight (individual health) and barriers and facilitators to this type of displacement (environmental health). Considering that attitudes cultivated in childhood are very likely to remain in adulthood, active transportation on the school path can be a strategy in creating h ealthy and sustainable habits that contribute to a better quality of life, as long as its determinants and condit ions are considered...(AU)

Transportadores de iones en pulmón: Uso como dianas terapéuticas / Ion transporters in the lungs. Use as therapeutic targets

Los canales de cloruros, de sodio, de bicarbonato y los de agua (aquaporinas) se coordinan para mantener la cubierta líquido superficial de las vías respiratorias, que es necesaria para el aclaramiento mucociliar. El mecanismo general para el transporte de electrolitos y agua depende principalmente de la expresión diferencial y distribución de los transportadores y bombas de iones. Los iones y el agua se mueven a través de las vía paracelular o transcelular. La ruta transcelular del transporte de electrolitos requiere un transporte activo (dependiente de ATP) o pasivo (siguiendo gradientes electroquímicos) de iones. La ruta paracelular es un proceso pasivo que está controlado, en última instancia, por los gradientes electroquímicos transepiteliales predominantes. La fibrosis quística es una enfermedad hereditaria que se produce por mutaciones en el gen que codifica la proteína reguladora de la conductibilidad transmembrana de la fibrosis quística (CFTR) que actúa como un canal de cloro y cumple funciones de hidratación del líquido periciliar y mantenimiento del pH luminal. La disfunción del canal de cloro en el epitelio respiratorio determina una alteración en las secreciones bronquiales, con aumento de su viscosidad y alteración de la depuración mucociliar y que asociado a procesos infecciosos puede conducir a daño pulmonar irreversible. La disfunción del CFTR, también se ha visto implicado en la patogénesis de la pancreatitis aguda, en la enfermedad pulmonar obstructiva crónica y la hiperreactividad en el asma. Existen fármacos que aprovechan los mecanismos fisiológicos en el transporte de iones, con un objetivo terapéutico.

The chloride channels, sodium and bicarbonate channels, and aquaporin water channels are coordinated to maintain the airway surface liquid that is necessary for mucociliary clearance. The general mechanism for the transport of electrolytes and fluids depends mainly on the differential expression and distribution of ion transporters and pumps. Ions and water move through the paracellular or transcellular pathways. The transcellular route of electrolyte transport requires an active transport (dependent on ATP) or passive (following electrochemical gradients) of ions. The paracellular pathway is a passive process that is ultimately controlled by the predominant transepithelial electrochemical gradients. Cystic fibrosis is a hereditary disease that is produced by mutations in the gene that encode cystic fibrosis transmembrane conductance regulatory protein (CFTR) that acts as a chloride channel and performs functions of hydration of periciliary fluid and maintenance of luminal pH. The dysfunction of the chlorine channel in the respiratory epithelium determines an alteration in the bronchial secretions, with an increase in its viscosity and alteration of the mucociliary clearance and that associated with infectious processes can lead to irreversible lung damage. CFTR dysfunction has also been implicated in the pathogenesis of acute pancreatitis, chronic obstructive pulmonary disease, and bronchial hyperreactivity in asthma. There are drugs that exploit physiological mechanisms in the transport of ions with a therapeutic objective.

Norma técnica de salud sobre preparación, embalaje y documentación para el transporte seguro de sustancias infecciosas / Technical health standard on preparation, packaging and documentation for the safe transport of infectious substances

El documento contiene la finalidad, objetivos, ámbito de aplicación, base legal, consideraciones generales y específicas sobre la preparación, embalaje y documentación para el transporte seguro de sustancias infecciosas.

Expression of myo-inositol cotransporters in the sciatic nerve and dorsal root ganglia in experimental diabetes

The transport of myo-inositol is the main mechanism for the maintenance of its high intracellular levels. We aimed to measure the mRNA and protein levels of myo-inositol cotransporters in the sciatic nerve (SN) and dorsal root ganglia (DRG) during experimental diabetes. Streptozotocin-induced (STZ; 4, 8, and 12 weeks; 65 mg/kg; ip) diabetic rats (DB) and age-matched euglycemic (E) rats were used for the analysis of mRNA and protein levels of sodium myo-inositol cotransporters 1, 2 (SMIT1, SMIT2) or H+/myo-inositol cotransporter (HMIT). There was a significant reduction in the mRNA levels for SMIT1 in the SN and DRG (by 36.9 and 31.0%) in the 4-week DB (DB4) group compared to the E group. SMIT2 was not expressed in SN. The mRNA level for SMIT2 was up-regulated only in the DRG in the DB4 group. On the other hand, the protein level of SMIT1 decreased by 42.5, 41.3, and 44.8% in the SN after 4, 8, and 12 weeks of diabetes, respectively. In addition, there was a decrease of 64.3 and 58.0% of HMIT in membrane and cytosolic fractions, respectively, in the SN of the DB4 group. In the DRG, there was an increase of 230 and 86.3% for SMIT1 and HMIT, respectively, in the DB12 group. The levels of the main inositol transporters, SMIT1 and HMIT, were greatly reduced in the SN but not in the DRG. SMIT-1 was selectively reduced in the sciatic nerve during experimental STZ-induced diabetes.

Azole resistance in Candida spp. isolated from Catú Lake, Ceará, Brazil: an efflux-pump-mediated mechanism

Abstract Since, there is no study reporting the mechanism of azole resistance among yeasts isolated from aquatic environments; the present study aims to investigate the occurrence of antifungal resistance among yeasts isolated from an aquatic environment, and assess the efflux-pump activity of the azole-resistant strains to better understand the mechanism of resistance for this group of drugs. For this purpose, monthly water and sediment samples were collected from Catú Lake, Ceará, Brazil, from March 2011 to February 2012. The obtained yeasts were identified based on morphological and biochemical characteristics. Of the 46 isolates, 37 were Candida spp., 4 were Trichosporon asahii, 3 were Cryptococcus laurentii, 1 Rhodotorula mucilaginosa, and 1 was Kodamaea ohmeri. These isolates were subjected to broth microdilution assay with amphotericin B, itraconazole, and fluconazole, according to the methodology standardized by the Clinical and Laboratory Standards Institute (CLSI). The minimum inhibitory concentrations (MICs) of amphotericin B, itraconazole, and fluconazole were 0.03125–2 µg/mL, 0.0625 to ≥16 µg/mL, and 0.5 to ≥64 µg/mL, respectively, and 13 resistant azole-resistant Candida isolates were detected. A reduction in the azole MICs leading to the phenotypical reversal of the azole resistance was observed upon addition of efflux-pump inhibitors. These findings suggest that the azole resistance among environmental Candida spp. is most likely associated with the overexpression of efflux-pumps.

Interaction between functional nano-hydroxyapatite and cells and the underlying mechanisms / 中南大学学报(医学版)

OBJECTIVE@#To explore the interaction between arginine functionalized hydroxyapatite (HAP/Arg) nanoparticles and endothelial cells, and to investigate mechanisms for endocytosis kinetics and endocytosis.
@*METHODS@#Human umbilical vein endothelial cells (HUVECs) were selected as the research model.Cellular uptake of HAP/Arg nanoparticles were observed by laser scanning confocal microscopy.Average fluorescence intensity of cells after ingestion with different concentrations of HAP/Arg nanoparticles were determined by flow cytometer and atomic force microscopy.
@*RESULTS@#The HAP/Arg nanoparticles with doped terbium existed in cytoplasm, and most of them distributed around the nucleus area after cellular uptake by HUVECs. Cellular uptake process of HAP/Arg nanoparticles in HUVECs was in a time and concentration dependent manner. 4 h and 50 mg/L was the best condition for uptake. HAP/Arg nanoparticles were easier to be up-taken into the cells than HAP nanoparticles without arginine functionalized.
@*CONCLUSION@#HAP/Arg nanoparticles are internalized by HUVECs cells through an active transport and energy-dependent endocytosis process, and it is up-taken by cells mainly through caveolin-mediated endocytosis, but the clathrin-dependent endocytic pathway is also involved..

Exposure of free-living jaguars to Toxoplasma gondii, Neospora caninum and Sarcocystis neurona in the Brazilian Pantanal / Exposição de onças-pintadas a Toxoplasma gondii, Neospora caninum e Sarcocystis neurona no Pantanal brasileiro

Toxoplasma gondii, Neospora caninum and Sarcocystis neurona are related apicomplexan parasites that cause reproductive and neurological disorders in a wide range of domestic and wild animals. In the present study, the immunofluorescence antibody test (IFAT) was used to investigate the presence of antibodies against T. gondii, N. caninum and S. neurona in the sera of 11 free-living jaguars (Panthera onca) in two protected areas in the Pantanal region of Mato Grosso state, Brazil. Ten jaguars (90.9%) showed seropositivity for T. gondii, eight (72.7%) for S. neurona, and seven (63.6%) for N. caninum antigens. Our findings reveal exposure of jaguars to these related coccidian parasites and circulation of these pathogens in this wild ecosystem. To the best of our knowledge, this is the first serological detection of N. caninum and S. neurona in free-living jaguars.

Toxoplasma gondii, Neospora caninum e Sarcocystis neurona são coccídios relacionados responsáveis por causar desordens reprodutivas e neurológicas em uma ampla variedade de animais domésticos e selvagens. No presente estudo, a Reação de Imunofluorescência Indireta (RIFI) foi utilizada para investigar a presença de anticorpos contra T. gondii, N. caninum e S.neurona em soros de 11 onças-pintadas de vida livre (Panthera onca), provenientes de duas áreas protegidas na região do Pantanal do Estado de Mato Grosso, Brasil. Dez (90,9%), sete (63,6%) e oito (72,7%) onças amostradas foram soropositivas para T. gondii, N. caninum e S. neurona, respectivamente. Os resultados indicam a exposição a esses coccídios relacionados entre as onças-pintadas e a circulação ambiental desses patógenos nesse ecossistema selvagem. Este é o primeiro relato da detecção sorológica de N. caninum e S. neurona em onças-pintadas de vida livre.

Genotypic and phenotypic detection of efflux pump in Rhodococcus equi

The req_39680 gene, associated to a putative efflux system, was detected in 60% (54/90) of R. equi isolates by PCR. The phenotypic expression of efflux mechanism was verified in 20% of the isolates using ethidium bromide. For the first time, the expression of efflux mechanism was demonstrated in R. equi.

Radioiodine Therapy in Differentiated Thyroid Cancer: The First Targeted Therapy in Oncology

Iodide uptake across the membranes of thyroid follicular cells and cancer cells occurs through an active transport process mediated by the sodium-iodide symporter (NIS). The rat and human NIS-coding genes were cloned and identified in 1996. Evaluation of NIS gene and protein expression is critical for the management of thyroid cancer, and several approaches to increase NIS levels have been tried. Identification of the NIS gene has provided a means of expanding its role in radionuclide therapy and molecular target-specific theragnosis (therapy and diagnosis using the same molecular target). In this article, we describe the relationship between NIS expression and the thyroid carcinoma treatment using I-131 and alternative therapeutic approaches.

Study on transportation of Xiaochaihu Tang in Caco-2 cell model / 中国中药杂志

<p><b>OBJECTIVE</b>To study the transportation of Xiaochaihu Tang in Caco-2 cell model.</p><p><b>METHOD</b>The safety concentration of Xiaochaihu Tang in Caco-2 cells was determined by MTT assay. Then the Caco-2 cell model was used to investigate the bi-directional transportation of Xiaochaihu Tang. The multicomponents of Xiaochaihu Tang and the influence of time were measured by high performance liquid chromatography (HPLC).</p><p><b>RESULT</b>The P(app) values of wogonoside and wogonin were (1.23 +/- 0.09) x 10(-6), (1.07 +/- 0.89) x 10(-5) cm x s(-1) from the AP side to BL side, and (2.12 +/- 0.19) x 10(-6) and (7.12 +/- 1.02) x 10(-6) cm x s(-1) from the BL side to AP side, respectively. The P(appAP --> BL)/P(app BL --> AP) ratio of wogonoside and wogonin were 0.58 and 1.49, respectively. Baicalin, baicalein and glycyrrhizic acid could not permeate the Caco-2 cell model.</p><p><b>CONCLUSION</b>The transportation of wogonoside and wogonin in Caco-2 cell model may be a passive transportation.</p>

Effect of major components of maijunan tablets on the transport of hydrochlorothiazide in Caco-2 cell monolayer model / 药学学报

To study the effects of major components of Maijunan tablets, puerarin (Pue) and rhynchophylline (Rhy) on the transport of hydrochlorothiazide (Hct) Caco-2 cell monolayer model, the transport parameters of Hct, such as apparent permeability coefficient (P(app) (B --> A) and P(app) (A --> B)) and the ratio of P(app) (B --> A) versus P(app) (A --> B), were studied and compared when Hct was used solely and co-used with Pue and/or Rhy. The effects of drug concentrations, conveying times, P-glyprotein (P-gp) inhibitor verapamil and conveying Liq pH values on the transport of Hct in the above conditions were also investigated. The results indicated that the absorption of Hct in Caco-2 cell monolayer model could be a carrier-mediated active transport, along with the excretion action mediated by P-gp. Pue can decrease the excretion action of Hct mediated by P-gp, and Rhy had no significant effect on the transport of Hct. The co-use of Hct, Pue and Rhy enhanced the absorption of Hct. Meanwhile, conveying Liq pH value had significant influence on the transport of Hct. The absorption of Hct at pH 6.0 was higher than that at pH 7.4.

Can time delay be shortened in the treatment of acute myocardial infarction?: Experience from Korea acute myocardial infarction registry / 대한내과학회지

Time delay between medial contact and treatment in symptomatic patients with acute myocardial infarction (AMI) is the most important factor in the prediction of short and long-term mortality. The incidences of AMI has been increased in Korea rapidly. According to Korea Acute Myocardial Infarction Registry (KAMIR), pre-hospital delay is longer in Korean patients compared with Western patients, especially in patients with non-ST elevation myocardial infarction and in elderly female patients. Prompt seeking medical care in patients with suspected symptom of AMI can be achieved through patient and patient's family education, active transportation system of ambulance, and good cooperations of regional emergency centers. Shortening time delay in treatment of AMI will save patient's life and reduce medical costs in the future, especially in Korea.

Advances in study of metabolic activation of carboxyl-acid containing drugs by UGTs / 药学学报

The metabolic transformation of the drugs containing carboxylic acid groups can lead to the formation of acyl glucuronide metabolites through catalysis by glucuronosyltransferase, and produce pro-acyl glucuronide intermediate metabolites with electronic activity. Then, protein or DNA adducts appeared after a series of non-enzyme or enzyme reactions. These adducts would change the protein activity and potentially lead to idiosyncratic and genotoxicity. In this paper, we discussed the chemical activity, drug-induced mechanisms, distribution and toxicity resulting from this metabolic activation for these drugs, and stated the status and prospects of research in this field.

Dietary cholesterol and estrogen administration elevate brain apolipoprotein E in mice by different mechanisms.

Apolipoprotein (apo) E plays an important role in the whole body cholesterol homeostasis. Recent studies suggest that it may also be involved in the local cholesterol transport in the brain, and influence the pathogenesis of Alzheimer's disease (AD) by interacting with the beta-amyloid protein and brain lipoprotein receptors. Since apoE expression is highest in the brain, next only to the liver and associated with the pathogenesis of AD, we hypothesized that dietary and hormonal intervention, known to regulate hepatic apoE expression may also regulate brain apoE and thereby influence local cholesterol transport. To test this hypothesis, groups of male C57BL mice were fed either regular rodent chow or high fat (HF) and high cholesterol enriched diet for 3 weeks. In a separate study, groups of male mice were administered pharmacological doses of 17-beta estradiol for 5 consecutive days and sacrificed on the 6th day. As expected, HF diet elevated liver apoE mRNA and apoE synthesis. Similar to liver, brain apoE mRNA and synthesis also increased, following HF feeding. Estradiol administration increased liver apoE synthesis without affecting apoE mRNA. Interestingly, estradiol administration also increased the brain apoE synthesis, but without altering the brain apoE mRNA. These studies suggested that dietary cholesterol and estrogen administration elevated the brain apoE by different mechanisms.

Trocas materno-fetais dos eletrólitos / Fetomaternal exchange of electrolytes

A descrição do transporte placentário envolve informações sobre mecanismos, propriedades e regulação genética das substâncias moleculares. Nas trocas materno-fetais faz-se necessário atravessar uma camada de células do sinciotrofoblasto (microvilosidades e camada basal da membrana plasmática)bem como o tecido conectivo e o endotélio capilar fetal. Assim, a troca sanguínea entre as duas circulações materna e fetal por meio do espaço interviloso e dos capilares vilosos ocorre através da barreira placentária. Os tipos de transporte de substâncias através da placenta são variáveis. Diversos mecanismos de transporte do sódio têm sido demonstrados, embora o transporte ativo de K+ ainda não esteja bem esclarecido no ser humano. O transporte placentário de cálcio, magnésio e fósforo acontece por transporte ativo, o qual aumenta no último trimestre de gestação, e coincide com o aumento da mineralização do esqueleto fetal. Desta forma, o entendimento das relações entre as diversas substâncias do organismo e o transporte através da placenta se faz necessário para melhor compreender a nutrição fetal e a patogênese de algumas doenças intra-útero.

Mechanisms of resistance to carbapenems in meropenem- resistant Acinetobacter isolates from clinical samples.

PURPOSE: To analyze the resistance mechanisms in Acinetobacter species by phenotypic methods. METHODS: Antibiotic susceptibility profile for 150 clinical isolates of Acinetobacte r was determined by the standard disk diffusion method. Isolates detected to be meropenem resistant were tested further by broth microdilution minimum inhibitory concentration (MIC) for meropenem. The resistant isolates were also tested for metallo beta -lactamase (MBL) production by the double-disk approximation test, for AmpC beta-lactamase production and efflux pump detection by agar microdilution MIC with and without reserpine. RESULTS: Twenty-one isolates were found resistant to meropenem by the standard disk diffusion method. Nine samples were from patients admitted in intensive care units (ICUs). Broth microdilution MICs of the isolates revealed low-level resistance to meropenem. MBL was not produced by any of these isolates. AmpC beta -lactamases were produced by nine (43%) isolates. 'Efflux pump'-mediated resistance to meropenem was detected in two out of nine random isolates tested for the same. CONCLUSIONS: Carbapenem resistance is not uncommon in Acinetobacter isolates. AmpC production may cause carbapenem resistance. MBL and efflux pump may not be important causes of carbapenem resistance.

A probability wave theory on the ion movement across cell membrane / 生物医学工程学杂志

The ionic quantity across the channel of the cell membrane decides the cell in a certain life state. The theory analysis that existed on the bio-effects of the electro-magnetic field (EMF) does not unveil the relationship between the EMF exerted on the cell and the ionic quantity across the cell membrane. Based on the cell construction, the existed theory analysis and the experimental results, an ionic probability wave theory is proposed in this paper to explain the biological window-effects of the electromagnetic wave. The theory regards the membrane channel as the periodic potential barrier and gives the physical view of the ion movement across cell-membrane. The theory revises the relationship between ion's energy in cell channel and the frequency exerted EMF. After the application of the concept of the wave function, the ionic probability across the cell membrane is given by the method of the quantum mechanics. The numerical results analyze the physical factors that influences the ion's movement across the cell membrane. These results show that the theory can explain the phenomenon of the biological window-effects.

Assessing potential dietary toxicity of heavy metals in selected vegetables and food crops / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Heavy metals, such as cadmium, copper, lead, chromium and mercury, are important environmental pollutants, particularly in areas with high anthropogenic pressure. Their presence in the atmosphere, soil and water, even in traces can cause serious problems to all organisms, and heavy metal bioaccumulation in the food chain especially can be highly dangerous to human health. Heavy metals enter the human body mainly through two routes namely: inhalation and ingestion, ingestion being the main route of exposure to these elements in human population. Heavy metals intake by human populations through food chain has been reported in many countries. Soil threshold for heavy metal toxicity is an important factor affecting soil environmental capacity of heavy metal and determines heavy metal cumulative loading limits. For soil-plant system, heavy metal toxicity threshold is the highest permissible content in the soil (total or bioavailable concentration) that does not pose any phytotoxic effects or heavy metals in the edible parts of the crops does not exceed food hygiene standards. Factors affecting the thresholds of dietary toxicity of heavy metal in soil-crop system include: soil type which includes soil pH, organic matter content, clay mineral and other soil chemical and biochemical properties; and crop species or cultivars regulated by genetic basis for heavy metal transport and accumulation in plants. In addition, the interactions of soil-plant root-microbes play important roles in regulating heavy metal movement from soil to the edible parts of crops. Agronomic practices such as fertilizer and water managements as well as crop rotation system can affect bioavailability and crop accumulation of heavy metals, thus influencing the thresholds for assessing dietary toxicity of heavy metals in the food chain. This paper reviews the phytotoxic effects and bioaccumulation of heavy metals in vegetables and food crops and assesses soil heavy metal thresholds for potential dietary toxicity.

Optimization of trehalose loading in red blood cells before freeze-drying / 中国实验血液学杂志

The key points for better protection of trehalose in freeze-drying red blood cells (RBCs) are to resolve non-osmosis of trehalose to red blood cells and to make cytoplasmic trehalose to reach effective concentration. This study was aimed to investigate the regularity of loading RBCs with trehalose, screen out optimal loading condition and evaluate the effect of trehalose on physico-chemical parameters of RBCs during the period of loading. The cytoplasmic trehalose concentration in red blood cells, free hemoglobin and ATP level were determined at different incubation temperatures (4, 22 and 37 degrees C), different trehaolse concentrations (0, 200, 400, 600, 800 and 1000 mmol/L) and different incubation times (2, 4, 6, 8 and 10 hours), the cytoplasmic trehalose, free hemoglobin (FHb), hemoglobin (Hb) and mean corpuscular volume (MCV) in fresh RBCs and RBCs stored for 72 hours at 4 degrees C were compared, when loading condition was ensured. The results showed that with increase of incubation temperature, time and extracellular trehalose concentration, the loading of trehalose in RBCs also increased. Under the optimal loading condition, cytoplasmic trehalose concentration and free hemoglobin level of fresh RBCs and RBCs stored for 72 hours at 4 degrees C were 65.505 +/- 6.314 mmol/L, 66.2 +/- 5.002 mmol/L and 6.567 +/- 2.568 g/L, 16.168 +/- 3.922 g/L respectively. It is concluded that the most optimal condition of loading trehalose is that fresh RBCs incubate in 800 mmol/L trehalose solution for 8 hours at 37 degrees C. This condition can result in a efficient cytoplasmic trehalose concentration. The study provides an important basis for long-term preservation of RBCs.