重金属铬对金鱼的毒性效应及鳃的组织学影响

为了探讨重金属铬 (chromium, Cr) 对鱼类的毒性效应,为环境质量评价及环境监测提供可靠的科学依据。以金鱼 (Carassius auratus) 为受试动物,采用单因子急性毒性实验法及显微观察法,检测了Cr 对金鱼急性毒性作用以及鳃的组织学变化,并统计半数致死浓度 (Median lethal concentration, LC50 )和安全浓度 (SC)。结果表明：Cr 的24h, 48h, 72h, 96h的半致死浓度 (LC50) 分别为387.1 mg/L、370.9 mg/L、281.9 mg/L、200.2 mg/L,安全浓度 (Safe concentration, SC) 为102.176 mg/L。组织切片结果显示：Cr 使鳃小叶细胞脱落,鳃小叶变细。Cr 为中等偏高毒性的重金属污染物,对金鱼的毒性作用是随着体内积累的浓度增加而增强,并可造成鳃组织的严重受损。     

Osmoregulation in juvenile Chinese sturgeon (<Emphasis Type="Italic">Acipenser sinensis</Emphasis> Gray) during brackish water adaptation

The osmoregulation capabilities of 7-month-old juvenile Chinese sturgeon (Acipenser sinensis Gray) (128.8 ± 15 g) transferred directly from fresh water (0‰, 46 mOsmol kg⁻¹) to brackish water (10‰, 273 mOsmol kg⁻¹) were studied over a 20-day period. Changes in serum osmolarity, chloride (Cl⁻), sodium (Na⁺), potassium (K⁺) and calcium (Ca²⁺) ion concentrations, as well as gill and spiral valve Na⁺,K⁺-ATPase activities were measured at 3, 12, 24, 72, 216 and 480 h after transfer to BW. The serum osmolarity and ion concentrations (Na⁺, Cl⁻ and Ca²⁺) increased immediately after the transference to BW, reaching maximum at 24 h and returned to a new steady state at 216 h, while the FW control group maintained basal levels which showed lower (P < 0.05) than the BW group. Gill Na⁺,K⁺-ATPase activity of BW group exhibited an abrupt decrease in the first 3 h after transfer, but began to increase at 3 h, reaching a peak value at 24 h, and returned to a new steady state at 216 h. The differences between gill Na⁺,K⁺-ATPase activity of BW and FW fish were significant (P < 0.05) after 12 h. In contrast, Na⁺,K⁺-ATPase activity of the spiral valve showed transient increase after transference from FW to BW, and then decreased rapidly at 3 h, reaching the lowest at 24 h after transference. At 216 h after exposure to BW, Na⁺,K⁺-ATPase activities of the spiral valve increased slowly to the levels of FW control. The results of our study indicate the existence of hyposmoregulatory adaptive mechanisms in 7-month-old juvenile Chinese sturgeon which enable this fish to acclimate itself successfully to brackish water.     

Measurement of free thyroxine concentration in horses by equilibrium dialysis

The purpose of the study reported here was to validate measurement of free thyroxine (fT4) concentration in equine serum by equilibrium dialysis (fT4D), and to compare values with fT4 concentration measured directly and with total T4 (TT4) concentration. The fT4D, fT4, and TT4 concentrations were measured over a range of values in euthyroid horses and horses made hypothyroid by administration of propylthiouracil (PTU). Concentrations of fT4D (<1.8-83 pmol/L) were consistently higher than those of fT4 (<1-40 pmol/L). There was a significant (P < .001) regression of fT4D on fT4 in 503 samples from normal horses (y = 2.086x - 0.430). In baseline samples from 71 healthy euthyroid horses, fT4 concentration ranged from 6-21 pmol/L (median, 11 pmol/L; 95% confidence interval [CI]10.5-11.8 pmol/L), and fT4D concentration ranged from 7-47 pmol/L (median, 22 pmol/L; 95% CI 20.9-25.1 pmol/L). Free T4D, fT4, and TT4 concentrations were also measured in 34 ill horses. Horses consuming PTU and ill horses had significantly (P < .05) lower serum concentration of TT4, fT4, and fT4D than did clinically normal, healthy horses. If serum samples from ill horses were further subdivided into samples from horses that lived and samples from horses that died, fT4D concentration was not significantly different in ill horses that lived, compared with that in healthy horses, whereas fT4 concentration was still significantly decreased in ill horses that died (P < 0.001). We conclude that measurement of fT4 concentration by equilibrium dialysis is a valid technique in the horse, and its use may provide improved ability to distinguish nonthyroidal illness syndrome from hypothyroidism in that species.     

Significance of BNP and APACHE II score on prognosis assessment of critically ill patients

AIM: To evaluate the role of plasma B-type natriuretic peptide (BNP) level and the score of acute physiology and chronic health evaluation II (APACHE II) in the prognosis assessment of critically ill patients. METHODS: Sixty-two critically-ill patients in ICU fo the First Affiliated Hospital of Jinan University were enrolled from October 2009 to February 2010. The APACHE II score was calculated and plasma BNP level was measured within the first 24 h after admission. The correlations between BNP/APACHE II score and length of hospitalization, rate of mechanical ventilation application, duration of ventilation and fatality rate were analyzed.RESULTS: There were 44 survivals and 18 deaths in 62 admissions. The average APACHE II score and plasma BNP level in the survival group were higher than those in death group (P<0.01). Sixty-two patients were divided into 3 groups according to their APACHE II scores. With increased BNP level, APACHE II score, rate of mechanical ventilation application and fatality rate were also increased. CONCLUSION: The increasing level of BNP and APACHE II score have significant implications in prognosis assessment of survival rate, rate of mechanical ventilation application, duration of ventilation and length of hospitalization in critically ill patients.     

我国公路病害和养护浅析

从我国现阶段公路发展情况及使用状况入手,介绍公路的主要病害,并分析病害产生的原因。另外还从我国公路养护与维修的决策、分类以及存在的问题等三方面阐述了我国现阶段的公路养护现状;并对今后公路养护的发展趋势做了展望。     

Clinical Presentation,Progression, and Management of Five Cases of Ross River Virus Infection in Performance Horses Located in Southeast Queensland: A Longitudinal Case Series

Ross River virus (RRV), a mosquito-transmitted alphavirus prevalent in Australia, is believed to cause poor performance, lethargy, and muscle stiffness in Australian horses. However, disease progression and management is poorly documented. A better understanding of disease presentation, acute therapy, and long-term management is required. The aim of the study was to describe clinical presentation, diagnosis, acute treatment, and long-term management of RRV infection in horses. This study is a series of retrospective case reports. Clinical and diagnostic data were obtained from both veterinary records, and owner interviews for five performance horses that presented with acute poor performance coupled with serologic evidence of RRV exposure. Clinical and owner reports were evaluated from the time of presentation until the horses appeared asymptomatic and had returned to normal performance. Ross River virus was suspected to be the cause of generalized muscle stiffness and poor performance in five performance horses located in southeast Queensland between 2011 and 2015. Clinical symptoms included pyrexia, tachypnea, exercise intolerance, generalized muscle stiffness, synovial effusion, and edema of the lower limbs. Serologic investigations (ELISA and/or virus neutralization assay) detected antibody responses to RRV. Horses were treated with nonsteroidal anti-inflammatory drugs (n = 5) and disease-modifying osteoarthritis drugs (n = 2). Most horses returned to previous athletic capabilities between 7 and 12 months after the onset of symptoms. Not all horses in the study had preclinical serology or submitted paired blood samples for serology, meaning assumption of acute infection in those horses was made based on clinical signs coupled with positive serology. Ross River virus is a significant but poorly understood cause of poor performance in Australian horses. This report is the only one to document longitudinal management of performance horses affected by RRV infection. Much more research is needed to gain a better understanding of this infection in horses.