Prebasic molt initiation and progress in northern fulmars of the High Arctic: do molt and breeding overlap?

We examined feather molt progress of northern fulmars (Fulmarus glacialis) at Cape Vera in the Canadian High Arctic through opportunistic observation of individuals in flight from 2003 to 2006, and examination of bodies and wings of 127 individuals collected at the site, from 2003 to 2005. We found no evidence suggesting that fulmars shed primary feathers during breeding. Prebasic molt was initiated in the head, neck, sides, belly and back approximately 1 week before hatch. We failed to detect a sex effect on molt progress, but molt among breeders was delayed compared to molt in non- or failed breeders. This study constitutes a baseline we feel may be useful to: (1) researchers interested in feather replacement chronology, wherein feathers are used as sources of biological information; and (2) researchers interested in eventual assessment of relationships among large-scale environmental processes and molt progress in this species, especially in light of predicted changes to Arctic regions.     

A novel locus for dilated cardiomyopathy maps to canine chromosome 8

Dilated cardiomyopathy (DCM), the most common form of cardiomyopathy, often leads to heart failure and sudden death. While a substantial proportion of DCMs are inherited, mutations responsible for the majority of DCMs remain unidentified. A genome-wide linkage study was performed to identify the locus responsible for an autosomal recessive inherited form of juvenile DCM (JDCM) in Portuguese water dogs using 16 families segregating the disease. Results link the JDCM locus to canine chromosome 8 with two-point and multipoint lod scores of 10.8 and 14, respectively. The locus maps to a 3.9-Mb region, with complete syntenic homology to human chromosome 14, that contains no genes or loci known to be involved in the development of any type of cardiomyopathy. This discovery of a DCM locus with a previously unknown etiology will provide a new gene to examine in human DCM patients and a model for testing therapeutic approaches for heart failure.     

Nerve Growth Factor Protects the Cortical Neurons from Chemical Hypoxia-induced Injury

Previous studies showed that nerve growth factor (NGF) exerts protective effects on cultured neurons against various kinds of damage. However, a recent publication reported that exposure of NGF-treated PC12 cells to physical hypoxia resulted in a higher cell death rate when compared to the untreated controls. In the present study, we therefore investigated the effects of NGF on the hypoxic cortical neurons induced by potassium cyanide (KCN). We demonstrated that NGF at a higher concentration can significantly increase neuronal viability, decrease the release of lactate dehydrogenase and improve cellular morphology in the hypoxic cortical neurons. However, we also found that pretreatment of NGF was not able to completely revise the decreased cell viability and the increased leakage of lactate dehydrogenase (LDH) induced by KCN, although the indexes in the neurons treated with NGF and KCN were significantly higher than those in the neurons treated with KCN only. Analysis of the data showed that the incomplete revision of NGF should be not due to the dosage of NGF we used. It might be induced by the inability of NGF to inhibit all injury pathways induced by potassium cyanide.     

一期梅毒实验室诊断差异性研究

目的通过梅毒螺旋体初筛试验、确认试验和鉴别诊断试验,探讨一期梅毒实验室诊断差异性,最大限度减少漏诊与误诊,为深入研发新型早期梅毒诊断试剂奠定基础。方法依据2000年中国卫生部防疫司颁布的性病诊断标准,临床筛选一期梅毒患者86例（研究组）和非梅毒患者100例（对照组）,对患者血清进行甲苯胺红不加热血清试验（TRUST）初筛和梅毒螺旋体明胶颗粒凝集试验（TPPA）确认。筛选临床体征、TRUST法和TPPA法三者结果有差异的患者进一步鉴别诊断,鉴别诊断主要应用荧光定量PCR（FQ-PCR）法、免疫PCR法与自身抗体检测等试验。结果初筛TRUST法灵敏度和特异性分别为62．8％、93．0％;确认TPPA法灵敏度与特异性分别为66．3％、100％。TRUST法和TPPA法两者结果差异占12．8％;临床体征诊断、TRUST法和TPPA法三者结果差异占41．9％。TPPA法与TRUST法两者均阴性的一期梅毒患者中,FQ-PCR阳性率达88．0％,免疫PCR阳性率占40．0％。TPPA法阳性、TRUST法阴性的一期梅毒患者免疫PCR法与TPPA法结果一致;TPPA法阴性、TRUST法阳性11例患者中结核抗体阳性2例,类风湿因子阳性3例与抗Sm抗体结果阳性6例。结论一期梅毒患者实验室诊断结果差异性较大,漏诊与误诊的比例较高,有待研发新型的诊断试剂和提高诊断水平。     

副溶血性弧菌显色培养基检测效果初步评价

副溶血性弧菌(Vibrio parahaemolyticus)是一种重要的食源性致病菌,广泛存在于各种海产品中.由于传统培养基和检测方法费时费力,本研究设计开发了一种新型显色培养基HKC vibrio,通过应用于人工污染样品和实际样品检验,以法国科玛嘉弧菌显色平板CHROMagar vibrio和柠檬酸钠-硫代硫酸钠-氯化钠-蔗糖琼脂平板(TCBS)为对照,对显色培养基HKC vibrio的灵敏性、特异性和检测效果进行了初步评价.结果表明,HKC vibrio的灵敏性与CHROMagar vibrio和TCBS相当,并具有较好的特异性,HKC vibrio是非常有价值的分离平板,可大大提高副溶血性弧菌的检测效率.     

Dynamic Processing of Nociception in Cortical Network in Conscious Rats: A Laser-evoked Field Potential Study

(1) Field potential study in conscious rats provides a convenient and effective animal model for pain mechanism and pharmacological research. However, the spatial-temporal character of nociception processing in cortex revealed by field potential technique in conscious rats remains unclear. (2) In the present study, multi-channel field potentials evoked by noxious laser stimulation applied to the hind paw of conscious rats were recorded through 12 chronically implanted skull electrodes. Independent component analysis (ICA) was used to remove possible artifacts and to extract the specific nociception-related component. (3) Two fast sharp responses and one slow blunt response were evoked by noxious laser stimulation. Systemic morphine (5 mg/kg, i.p.) preferentially attenuated the amplitude of the slow blunt response while had no significant effect on the first two sharp responses. ICA revealed that those responses came from activities of contralateral anterior parietal area, medial frontal area and posterior parietal area. A movement artifact was also detected in this study. Partial directed coherence (PDC) analysis showed that there were changes of information flows from medial frontal and posterior parietal area to anterior parietal area after noxious laser stimulation. (4) Characterization of the spatio-temporal responses to noxious laser stimulation may be a valuable model for the study of pain mechanisms and for the assessment of analgesia.     

Direct actions of cortisol, thyroxine and growth hormone on IGF-I mRNA expression in sea bream hepatocytes

The present study aims to investigate potential regulatory effect of different growth-related hormones including growth hormone (GH), human insulin-like growth factor-I (hIGF-I), thyroxine (T₄), triiodothyronine (T₃) and cortisol, on insulin-like growth factor-I (IGF-I) mRNA expression of hepatocytes isolated from silver sea bream. By using real-time PCR, IGF-I mRNA expression profiles of hepatocytes in response to individual hormones were determined in vitro. Hepatocytes incubated with GH at concentrations of 10–1000 ng/mL showed significantly higher IGF-I expression, but the elevation was attenuated at high concentration of GH (1000 ng/mL). IGF-I expression remained unchanged in hepatocytes after incubation with hIGF-I. Hepatocytes incubated with T₄ at concentration of 1000 ng/mL exhibited a significant elevation in IGF-I expression, whereas no difference in IGF-I expression was demonstrated in hepatocytes after incubation with T₃. Upon incubation with cortisol (1–1000 ng/mL), IGF-I expression was significantly decreased in hepatocytes in a dose-dependent manner. Our study demonstrated that GH, T₄, and cortisol had direct modulatory effects on IGF-I expression in fish hepatocytes in vitro.     

Angiogenic profiling and comparison of immortalized endothelial cells for functional genomics

Genomics efforts of the past decade have resulted in the identification of numerous genes with putative roles in disease processes, including tumor angiogenesis. To functionally validate these genes, cultured endothelial cells are indispensable tools, though these may not completely mimic the phenotype of tissue endothelial cells as the proper microenvironment is lacking. To obtain experimental data representative of normal physiology, the use of primary endothelial cells is preferred. However, these cells are usually limited in passage number, can be difficult to obtain and show great interindividual variety. Furthermore, transfection efficiency is very limited in primary cells, hampering applications in functional genomics and gene function analysis. The use of properly characterized alternative endothelial cell sources is therefore warranted. Here, we compared immortalized endothelial cells - HMEC, RF24 and EVLC2 - with primary HUVEC. We show that RF24, and to a slightly lesser extent HMEC, resembles primary HUVEC most on all facets examined. RF24, in contrast to EVLC2, express the endothelial markers CD31, CD34, CD105, vWF and VE-cadherin, and are capable of migration and tube formation in vitro. Furthermore, the expression levels of angiogenic growth factors and their receptors are comparable to that of primary EC. In addition, whereas primary HUVEC are resistant to transfection using common lipophilic transfection reagents, HMEC and RF24 could be readily transfected. Hence, these cells pose a valuable tool for functional genomics in angiogenesis research.     

Epipelic and pelagic primary production in Alaskan Arctic lakes of varying depth

We compared on eight dates during the ice-free period physicochemical properties and rates of phytoplankton and epipelic primary production in six arctic lakes dominated by soft bottom substrate. Lakes were classified as shallow ( < 2.5 m), intermediate in depth (2.5 m <  < 4.5 m), and deep ( > 4.5 m), with each depth category represented by two lakes. Although shallow lakes circulated freely and intermediate and deep lakes stratified thermally for the entire summer, dissolved oxygen concentrations were always >70% of saturation values. Soluble reactive phosphorus and dissolved inorganic nitrogen (DIN = NO₃ ⁻–N + NH₄ ⁺–N) were consistently below the detection limit (0.05 μmol l⁻¹) in five lakes. However, one lake shallow lake (GTH 99) periodically showed elevated values of DIN (17 μmol l⁻¹), total-P (0.29 μmol l⁻¹), and total-N (33 μmol l⁻¹), suggesting wind-generated sediment resuspension. Due to increased nutrient availability or entrainment of microphytobenthos, GTH 99 showed the highest average volume-based values of phytoplankton chlorophyll a (chl a) and primary production, which for the six lakes ranged from 1.0 to 2.9 μg l⁻¹ and 0.7–3.8 μmol C l⁻¹ day⁻¹. Overall, however, increased resulted in increased area-based values of phytoplankton chl a and primary production, with mean values for the three lake classes ranging from 3.6 to 6.1 mg chl a m⁻² and 3.2–5.8 mmol C m⁻² day⁻¹. Average values of epipelic chl a ranged from 131 to 549 mg m⁻² for the three depth classes, but levels were not significantly different due to high spatial variability. However, average epipelic primary production was significantly higher in shallow lakes (12.2 mmol C m⁻² day⁻¹) than in intermediate and deep lakes (3.4 and 2.4 mmol C m⁻² day⁻¹). Total primary production (6.7–15.4 mmol C m⁻² day⁻¹) and percent contribution of the epipelon (31–66%) were inversely related to mean depth, such that values for both variables were significantly higher in shallow lakes than in intermediate or deep lakes. Handling editor: L. Naselli-Flores