Blockade of angiotensin-converting enzyme or tumor necrosis factor-α reverses maternal high-fat diet-induced sensitization of angiotensin II hypertension in male rat offspring.

Maternal high-fat diet (HFD) is associated with metabolic syndrome and cardiovascular diseases in adult offspring. Our previous study demonstrated that maternal HFD enhances pressor responses to ANG II or a proinflammatory cytokine (PIC), which is associated with increased expression of brain renin-angiotensin system (RAS) components and PICs in adult offspring. The present study further investigated whether inhibition of angiotensin-converting enzyme (ACE) or tumor necrosis factor-α (TNF-α) blocks sensitization of ANG II hypertension in offspring of HFD dams. All offspring were bred from dams with normal fat diet (NFD) or HFD starting two weeks before mating and maintained until weaning of the offspring. Then the weaned offspring were treated with an ACE inhibitor (captopril) or a TNF-α inhibitor (pentoxifylline) in the drinking water through the end of testing with a slow-pressor dose of ANG II. RT-PCR analyses of the lamina terminalis and paraventricular nucleus revealed upregulation of mRNA expression of several RAS components and PICs in male offspring of HFD dams when compared with age-matched offspring of NFD dams. The enhanced gene expression was attenuated by blockade of either RAS or PICs. Likewise, ANG II administration produced an augmented pressor response in offspring of HFD dams. This was abolished by either ACE or TNF-α inhibitor. Taken together, this study provides mechanistic evidence and a therapeutic strategy that systemic inhibition of the RAS and PICs can block maternal HFD-induced sensitization of ANG II hypertension, which is associated with attenuation of brain RAS and PIC expression in offspring.

Maternal high-fat diet acts on the brain to induce baroreflex dysfunction and sensitization of angiotensin II-induced hypertension in adult offspring.

Accumulating evidence indicates that maternal high-fat diet (HFD) is associated with metabolic syndrome and cardiovascular disease in adult offspring. The present study tested the hypothesis that maternal HFD modulates the brain renin-angiotensin system (RAS), oxidative stress, and proinflammatory cytokines that alter angiotensin II (ANG II) and TNF-α actions and sensitize the ANG II-elicited hypertensive response in adult offspring. All offspring were cross fostered by dams on the same or opposite diet to yield the following four groups: offspring from normal-fat control diet-fed dams suckled by control diet-fed dams (OCC group) or by HFD-fed dams (OCH group) and offspring from HFD-fed dams fed a HFD suckled by control diet-fed dams (OHC group) or by HFD-fed dams (OHH group). RT-PCR analyses of the lamina terminalis and paraventricular nucleus indicated upregulation of mRNA expression of several RAS components, NADPH oxidase, and proinflammatory cytokines in 10-wk-old male offspring of dams fed a HFD during either pregnancy, lactation, or both (OHC, OCH, and OHH groups). These offspring also showed decreased cardiac baroreflex sensitivity and increased pressor responses to intracerebroventricular microinjection of either ANG II or TNF-α. Furthermore, chronic systemic infusion of ANG II resulted in enhanced upregulation of mRNA expression of RAS components, NADPH oxidase, and proinflammatory cytokines in the lamina terminalis and paraventricular nucleus and an augmented hypertensive response in the OHC, OCH, and OHH groups compared with the OCC group. The results suggest that maternal HFD blunts cardiac baroreflex function and enhances pressor responses to ANG II or proinflammatory cytokines through upregulation of the brain RAS, oxidative stress, and inflammation. NEW & NOTEWORTHY The results of our study indicate that a maternal high-fat diet during either pregnancy or lactation is sufficient for perinatal programming of sensitization for hypertension, which is associated with hyperreactivity of central cardiovascular nuclei that, in all likelihood, involves elevated expression of the renin-angiotensin system, NADPH oxidase, and proinflammatory cytokines. The present study demonstrates, for the first time, the central mechanism underlying maternal high-fat diet sensitization of the hypertensive response in adult offspring.

Isoniazid promotes the anti-inflammatory response in zebrafish associated with regulation of the PPARγ/NF-κB/AP-1 pathway.

OBJECTIVE: Zebrafish inflammation models were used to evaluate the anti-inflammatory activity of isoniazid (INH) and preliminarily investigate the underlying mechanism. METHODS: Local, acute, and systemic zebrafish inflammation models were established by tail cutting, copper sulfate (CuSO4), and lipopolysaccharide (LPS) endotoxin treatments, respectively, to evaluate the anti-inflammatory activity of INH. Zebrafish in the inflammatory state were exposed to different concentrations of INH (1, 2, and 4 mM) for 72 h to observe changes in the migration and accumulation of inflammatory cells and measure the reactive oxygen species (ROS) content in zebrafish after INH treatment. The transcription levels of inflammation-related genes in zebrafish from all groups were measured using real-time polymerase chain reaction (RT-PCR). RESULTS: Compared to those observed in the control inflammation model group, the numbers of migrated and accumulated inflammatory cells in zebrafish in the INH-treated group significantly decreased. INH significantly decreased the ROS content induced by LPS. Compared to that observed in the LPS model group, INH at 1 and 2 mM significantly increased the expression of PPARγ and inhibited the expression of NF-κB, iκbαa, and AP-1 as well as the inflammatory factors TNF-ɑ, TGF-ß, IL-1b, and COX-2. CONCLUSION: In this study, different zebrafish inflammation models were used to confirm that INH has anti-inflammatory activity. The associated mechanism may occur through the inhibition of ROS release, activation of PPARγ expression, inhibition of the transcriptional regulatory activity of NF-κB and AP-1, and reduction of INH inflammatory factor expression to relieve inflammation. The results of this study provide references for the clinical application of INH.

[Characteristics of fish aggregation devices (FADs)and associated tuna schools behavior in Chinese tuna purse seine fishery.] / æˆ‘å›½çƒ­å¸¦é‡‘æžªé±¼å›´ç½‘äººå·¥é›†é±¼è£ ç½®ç‰¹å¾åŠéšé™„é±¼ç¾¤è¡Œä¸º.

The use of fish aggregation devices (FADs) can increase catchability of tuna purse seine for associated tuna schools. In the past decades, large scale deployments of FADs have drawn the international attention due to their negative effects on the marine environment. Finding a FAD design ecologically and economically compatible has therefore become a challenge for tuna purse seine fishe-ry. Nowadays, knowledge and comprehension of interaction between FADs and catch species are quite lacking as a result of limited experimental investigation. We interviewed the captain of Chinese tuna purse seiner based on questionnaire to summarize the status of FADs deployment strategy, structural design, capture and ecological characteristics, and the behavior characteristics of associa-ted schools from the perspective of fishermen's knowledge and experience. We also quantified the cognitive differences of the investigated issues based on the index of consistency (IoC). Our results showed that: 1) the average number of year-round FADs deployment was (102±37) per vessel, and the number of that being lost was (72±1). 2) empirical knowledge from fishing masters indicated that man-made FADs could attract more tuna than natural floating objects (e.g. logs). Submerged structure was the predominant mechanism for aggregating tunas around the FADs. Hanging attractors (e.g. palm leaves) would facilitate the aggregation of tunas. 3) Fishing masters' observations in practical operation revealed that the duration needed for tunas to be associated with a FAD was around 32 days, and fish aggregation would tend to stabilize in the following month. Entanglement of sea turtles and sharks by netting was incidental events. 4) Most fishing masters had identical opinion on "bio-fouling was helpful for FADs to attract tunas" (IoC=0.73) and "modifying FADs design to reduce the detectability by other vessels" (IoC=0.73), while the answers for "the effect of raft type on tuna attraction capability" (IoC=0.34) were quite different. 5) The results of questionnaire suggested that the current design of FADs used by Chinese tropical tuna purse seiner had high risks of detected by other vessels and increased vulnerability of non-target species to fishery. Moreover, our results provided valuable references that promote sustainable exploitation of purse seine in a way of reconciling profitability with ecological preservation.

Novel peroral cholangioscopy-directed lithotripsy using an ultraslim upper endoscope for refractory Mirizzi syndrome: A case report.

RATIONALE: Mirizzi syndrome (MS) is an uncommon condition characterized by common hepatic duct (CHD) compression by an impacted gallbladder or cystic duct stones or adjacent inflammation. To date, a standardized therapeutic strategy for MS has not been established yet, owing to its complex clinical presentation. Thus, researchers still have to develop new optimized approaches to solve this problem. Herein, we describe a patient with refractory MS who underwent a successful treatment by novel hybrid anchoring balloon-guided direct peroral cholangioscopy (POC) using an ultraslim endoscope. PATIENT CONCERNS: A 56-year-old man with a history of biliary stone was referred to our hospital for complaints of discomfort in the right upper quadrant of the abdomen and obstructive jaundice. Endoscopic retrograde cholangiopancreatography showed an 18-mm impacted stone at the level of the cystic duct, which compressed the CHD. The CHD had local stricture, with its upstream and intrahepatic bile duct dilation. DIAGNOSES: He was diagnosed with type I MS. INTERVENTIONS: Initially, the patient received an endoscopic major sphincterotomy. However, conventional stone extraction, including mechanical lithotripsy, was unsuccessful. Then, after signing the informed consent form for further treatment, he was successfully treated with novel hybrid anchoring balloon-guided direct POC. OUTCOMES: The patient had no operative complications and was discharged with cleared ducts. At the 3-year follow-up, he was asymptomatic. LESSONS: Our novel hybrid anchoring balloon-guided direct POC may be an effective alternative treatment approach for difficult gallbladder cases, such as refractory MS.

Particulate matter (PM10) induces cardiovascular developmental toxicity in zebrafish embryos and larvae via the ERS, Nrf2 and Wnt pathways.

Particulate matter (PM10) is one of the most important indicators of the pollution that characterizes air quality. Epidemiological studies have shown that PM10 can cause cardiovascular-related diseases in the population. And, we studied the developmental toxicity of PM10 and the underlying mechanism of its effects on the cardiovascular system of zebrafish embryo/larva. Changes in cardiac morphology, sinus venosus and bulbus arteriosus (SV-BA) distance, heart rate, vascular subintestinalis, blood flow, returned blood volume, and reactive oxygen species (ROS) level were measured, and changes in the expression levels of certain genes were assessed via RT-PCR. The results showed that PM10 caused a significant increase in pericardial sac area and SV-BA distance, a decrease in heart rate, inhibition of vascular subintestinalis growth, blood flow obstruction, reduced venous return, and other cardiovascular toxicities. PM10 induced an increase in the ROS level and significant increases in the expression levels of ERS signalling pathway factors and Nrf2 signalling pathway factors. The expression levels of the Wnt pathway-related genes also showed significant changes. Furthermore, ROS inhibitor N-Acetyl-l-cysteine (NAC) could ameliorate the cardiovascular toxicity of PM10 in zebrafish larvae. It is speculated that PM10 may result in cardiovascular toxicity by inducing higher ROS levels in the body, which could then induce ERS and lead to defects in the expression of genes related to the Wnt signalling pathway. The Nrf2 signalling pathway was activated as a stress compensatory mechanism during the early stage of PM10-induced cardiovascular injury. However, it was insufficient to counteract the PM10-induced cardiovascular toxicity.

[Comparison of generalized additive model and boosted regression tree in predicting fish community diversity in the Yangtze River Estuary, China]. / GAM模型和BRTæ¨¡åž‹åœ¨é•¿æ±Ÿå£é±¼ç±»ç¾¤è½å¤šæ ·æ€§é¢„æµ‹ä¸­çš„æ¯”è¾ƒ.

Yangtze River Estuary is the biggest estuarine ecosystem in the western Pacific Ocean. Evaluating fish community in this ecosystem can provide scientific basis for its restoration and mana-gement. Generalized additive model (GAM) and boosted regression tree (BRT) were built to examine the relationship between fish community diversity and environmental and spatio-temporal variables based on data collected during 2012-2014. Combined with linear regression analysis, a cross validation was used to evaluate the fitness and predictive performance of both models. We plotted the spatial distribution of fish community diversity and richness in each station of the Yangtze River Estuary in 2014. The results showed that salinity, pH and chlorophyll-a had the most contribution on diversity, while pH, dissolved oxygen and chlorophyll-a were the most contributive variables on richness. BRT models showed better fitness and lower prediction error than GAM models. In contrast to GAM models, BRT models could distinguish the fish community index in each station area with respect to the spatial prediction. The diversity index in external water was obviously greater than that in internal water. Meanwhile, the station at higher latitude had a higher diversity index in both external and internal water.

Changes in aortic endothelium ultrastructure in male rats following castration, replacement with testosterone and administration of 5alpha-reductase inhibitor.

AIM: To investigate the relationship between low androgen level and ultrastructure of vascular endothelium. METHODS: Forty-eight male Sprague-Dawley rats were randomly divided into four groups: group A, normal rats with sham castration; group B, castrated rats; group C, castrated rats given testosterone (T) undecanoate; and group D, intact rats treated with 5alpha-reductase inhibitor. After 10 weeks of treatment or castration, rats in different groups were killed and serum T, free T (FT) and dihydrotestosterone (DHT) were measured. The aortic endothelia were scanned under electron microcopy and the Vascular Endothelium Structure Score (VESS) was computed. RESULTS: Serum T and FT concentrations of rats in group B were significantly lower than those of the other three groups (P < 0.01); DHT concentrations of group D rats were significantly decreased (P < 0.01) when compared with those of groups A and C. Rats in groups B and D rats (with low androgen levels) had obvious damage to their endothelial surfaces, which appeared crimpled, rough, adhesive and ruptured, and had high destruction of VESS. CONCLUSION: These results suggest that low concentrations of T and DHT are associated with ultrastructural damage of the aortic endothelia in male rats.

[Protective effect of rosiglitazone on myocardium in diabetic cardiomyopathy of rats].

OBJECTIVE: To investigate the protective effect of PPARgamma ligands rosiglitazone on myocardium in diabetic cardiomyopathy of rats. METHODS: The rat model of diabetes was induced by administration of streptozotocin (STZ) for 6 or 10 weeks. In the treatment group the STZ-induced diabetic rats were treated with rosiglitazone. The left ventricular muscle specimens were taken from treatment and control group; then were examined under transmission electron microscope. RESULT: Cardiac myofibrils of diabetic rats in control group were obviously fewer and broken. There were fewer and smaller dissolved mitochondria with incomplete membrane and mixed cristae and karyopyknosis. Myocardium of diabetic rats treated with rosiglitazone was markedly improved although their blood glucose levels were still high. CONCLUSION: Hyperglycemia can cause destruction of myocardial cell structure. Rosiglitazone has protective effect on myocardial cells of diabetic rats, which seems to be independent of blood glucose levels.

[Development of open cycling air pressure control system used for glaucoma research].

OBJECTIVE: To develop and set up a new culture system, which can apply pressure to cultured cells with open cycling air. The effects of this new system on the pH value, HCO(3)(-) concentration, O(2) pressure (pO(2)), CO2 pressure (pCO(2)) and the proliferation of retinal pigment epithelium (RPE) were tested to evaluate its efficiency in the study of glaucoma. METHODS: In the open cycling air pressure control culture system, the pressure inside the culture flasks was controlled by increase or decrease of the perfuse airflow. The influence of different culture systems (normal pressure culture system, open cycling air pressure control system and occlusive pressure control system) on the pH value, HCO(3)(-) concentration, pO(2), pCO(2) and proliferation of RPE were tested. The data were analyzed with SPSS software. RESULTS: The open cycling air pressure control culture system worked effectively, the pressure inside the culture flask can be controlled from 0 to 100 mm Hg. The difference of pH value, HCO(3)(-) concentration, pO(2), and pCO(2) of culture medium and the proliferation of RPE between normal pressure culture system and open cycling air pressure control system were not significant (P = 0.927, 0.887, 0.818, 0.770, 0.719, respectively). There was significant difference in these data between normal pressure culture system and occlusive pressure control system (P = 0.001, 0.000, 0.000, 0.000, 0.000, respectively). CONCLUSIONS: A new designed standard culture system applying pressure to cells with open cycling air was effective at pressure controlling and pH value, HCO(3)(-) concentration, pO(2) and pCO(2) controlling. This system may act as an ideal model in the experimental study of glaucoma.

Absolutely Exponential Stability and Temperature Control for Gas Chromatograph System Under Dwell Time Switching Techniques.

This paper provides a design strategy for temperature control of the gas chromatograph. Usually gas chromatograph is modeled by a simple first order system with a time-delay, and a proportion integration (PI) controller is widely used to regulate the output of the gas chromatograph to the desired temperature. As the characteristics of the gas chromatograph varies at the different temperature range, the single-model based PI controller cannot work well when output temperature varies from one range to another. Moreover, the presence of various disturbance will further deteriorate the performance. In order to improve the accuracy of the temperature control, multiple models are used at the different temperature ranges. With a PI controller designed for each model accordingly, a delay-dependent switching control scheme using the dwell time technique is proposed to ensure the absolute exponential stability of the closed loop. Experiment results demonstrate the effectiveness of the proposed switching technique.

[Electrophysiological effects of ischemia/reperfusion (I/R) on pacemaker cells in guinea-pig left ventricular outflow tract and the effects of antiarrhythmic drugs treatment].

OBJECTIVE: To investigate the electrophysiological effects of ischemia/reperfusion (I/R) on the spontaneous slow response action potentials in guinea-pig left ventricular outflow tract and the effects of antiarrhythmic drugs onI/R. METHODS: The action potentials of pacemaker cells in guinea-pig left ventricular outflow tract were recorded by conventional intracellular microelectrode technique. The influences of ischemia(I) 10 min, reperfusion(R) 2 min, and R 15min on the spontaneous slow response potentials were investigated. The effects of lidocaine, propafenone, amiodarone, verapamil, adenosine, and sodium nitroprusside (SNP) on I/R were also studied. Electrophysiological parameters were examined:velocity of diastolic depolarization(VDD), rate of pacemaker firing(RPF), maximal diastolic potential(MDP), maximal rate of depolarization(Vmax), amplitude of action potential(APA), 50% and 90% of duration of action potential(APD50 and APD90). RESULTS: ①In I 10 min group, the values of VDD, RPF, Vmax and APA were decreased markedly compared with control group (P<0.05, P<0.01).In R 2 min group, VDD and RPF were increased significantly(P<0.01), MDP was increased notably(P<0.05), APD50 and APD90 were shortened significantly compared with I 10 min and control group. Vmax was increased markedly vs control group(P<0.05). APA was decreased notably vs I 10 min group (P<0.05), but was increased markedly vs control group(P<0.05). In R 15 min group, the action potentials recovered gradually to the levels of control group. ② Compared with I 10 min/R 2 min group, 1 µmol/L lidocaine, 10 µmol/L propafenone, 1 µmol/L amiodarone, 1 µmol/L verapamil, 50 µmol/L adenosine, and 10 µmol/L SNP decreased VDD and RPF significantly. CONCLUSIONS: I/R injury can trigger abnormal spontaneous activities of guinea-pig left ventricular outflow tract.The electrophysiological effects of I/R injury on left ventricular outflow tract can be treated by antiarrhythmic drugs.

[Electrophysiological effects of neurotransmitters on pacemaker cells in guinea pig left ventricular outflow tract].

This study was designed to explore the innervation of autonomic nervous system and the distribution of receptors on pacemaker cell membrane in guinea pig left ventricular outflow tract (aortic vestibule). By using conventional intracellular microelectrode technique to record action potentials, autonomic neurotransmitters and antagonists were used to investigate the electrophysiological features and regularities of spontaneous activity of left ventricular outflow tract cells. Electrophysiological parameters examined were: maximal diastolic potential (MDP), amplitude of action potential (APA), maximal rate of depolarization (V(max)), velocity of diastolic depolarization (VDD), rate of pacemaker firing (RPF), 50% and 90% of duration of action potential (APD(50) and APD(90)). The results are listed below: (1) Perfusion with 100 mumol/L isoprenaline (Iso) resulted in a significant increase in V(max) (P <0.05), VDD, RPF, and APA (P <0.01), a notable decrease in MDP (P<0.05), and also a marked shortening in APD(50) (P<0.01). Pretreatment with Iso (100 mumol/L), propranolol (5 mumol/L) significantly decreased RPF and VDD (P<0.01), decreased APA, MDP and V(max) (P<0.01) notably, prolonged APD(50) (P<0.01) and APD(90) (P<0.05) markedly. (2) Application of 100 mumol/L epinephrine (E) resulted in a significant increase in VDD (P<0.05), RPF (P<0.001), V(max) (P<0.05) and APA (P<0.001), and a notable shortening in APD(50) and APD(90) (P<0.05). (3) Perfusion with 100 mumol/L norepinephrine (NE) led to a significant increase in VDD, RPF, APA and V(max) (P<0.05), and a marked shortening in APD(50) (P<0.05). Pretreatment with NE (100 mumol/L), phentolamine (100 mumol/L) significantly decreased RPF and VDD, MDP and APA (P<0.01), decreased V(max) notably (P<0.05), prolonged APD(50) and APD(90) markedly (P<0.01). (4) During perfusion with 10 mmol/L acetylcholine (ACh), VDD and RPF slowed down notably (P<0.05), APA decreased significantly (P<0.001), V(max) slowed down notably (P<0.01), APD50 shortened markedly (P<0.05), Atropine (10 mmol/L) antagonized the effects of ACh (10 mumol/L) on APD(50) (P<0.05). These results suggest that there are probably alpha-adrenergic receptor (alpha-AR), beta-adrenergic receptor (beta-AR) and muscarinic receptor (MR) on pacemaker cell membrane of left ventricular outflow tract in guinea pig. The spontaneous activities of left ventricular outflow tract cells are likely regulated by sympathetic and parasympathetic nerves.

[Effect of Oxymatrine on cardiac function and left ventricular remodeling in rabbits after acute myocardial infarction].

OBJECTIVE: To observe the effect of Oxymatrine on left cardiac function and ventricular remodeling in rabbits after acute myocardial infarction. METHODS: Ligation of the left anterior descending artery was adopted to establish acute myocardial infarction model, forty eight rabbits were randomized into the sham operation group, model group and Oxymatrine group. Eight models were successfully established in each group. the sham operation group and model group were given conventional feed. Oxymatrine were gavage administration 0.5 ml/100 g, once a day, lasted for 4 weeks. Respectively in postoperative week, and three weeks, to observe the Oxymatrine on cardiac output (CO), left ventricular end systolic pressure (LVESP), left ventricular end-diastolic pressure (LVEDP), left indoor pressure change rate peak (dp/dtmax)), and left ventricular cavity internal diameter (D), ventricular weight index (VWI), ventricular weight (VW). RESULTS: Left ventricular anterior wall was from red to deep purple, electrocardiogram showed II guide ST-segment camber up ≥ 0.25 mv. Postoperative week in Oxymatrine group compared with model group, LVESP increased significantly (P < 0.01), LVEDP decreased obviously (P < 0.01); After three weeks in Oxymatrine group compared with model group, VW, VWI decreased (P < 0.05), D significantly reduced (P < 0.01); LVESP increased significantly (P < 0.01), LVEDP decreased obviously (P <0.01); dp/dt(max), CO increased (P < 0.05). CONCLUSION: After acute myocardial infarction in rabbit Oxymatrine can improve the left ventricular reconstruction parameters, increase cardiac output, and improve cardiac function.

[Reasons of drifting floating objects aggregating rainbow runner (Elagatis bipinnulata)].

Many pelagic species tend to aggregate under drifting floating objects. This has led to the development of drifting fish aggregation devices (FADs) to attract the tropical tunas for the tuna purse seine fishery. However, FADs can also attract other non-targeting small pelagic species such as rainbow runner Elagatis bipinnulata, although it is still unclear why those species can be attracted and aggregated under an FAD. Using the fishery biological data collected in the Western and Central Pacific Ocean by the scientific observers on board Chinese tuna purse seine fishing vessels, we evaluated the potential motivations for rainbow runner to aggregate under drifting objects. This study indicated 1) Fork length of rainbow runner ranged from 30.0 to 90.6 cm, with the dominant fork lengths of 60.0 to 80.0 cm, accounting for 76.3% of the total sampled fish, suggesting large rainbow runner dominating around the drifting objects; 2) Size (fork length) of E. bipinnulata at 50% maturity was 65.7 cm, and mature individuals were dominant under the FADs; and 3) Some commonly observed small fish species, such as Decapterus macarellus, Kyphosus cinerascens, Caranx sexfasciatus, Katsuwonus pelamis and the juveniles of Thunnus obesus and Thunnus albacares, were found in the stomach of rainbow runner, which suggested that rainbow runner under FAD preyed on other associated small pelagic species. As an oceanic predator associated with drifting objects, feeding is perhaps one of the most possible motivations for adult E. bipinnulata to aggregate under the FAD. Both the "concentration of food supply" hypothesis and the "comfortability stipulation" hypothesis can be used to explain why E. bipinnulata aggregate under drifting floating objects.

[Impact of fish aggregation devices on tropical tuna's behavioral pattern: a review].

Tuna prefers to aggregate around floating objects. Based on this behavioral characteristic, people developed fish aggregation devices (FADs) to trap tuna, and made the catch and fishing efficiency of tuna purse seine fisheries improved greatly. However, there still exist uncertainties whether the FADs can attract tuna and what's the potential impact of widely applying FADs in tuna purse seine fishery on tuna resources and oceanic pelagic ecosystem. Aiming at these uncertainties, scientists conducted a great deal experiments to study the behavioral biology of tuna around FADs. This paper reviewed the related classic and more credible experiments in the past 30 years, and summed up five behavioral patterns of the tunas around drifting and anchored FADs, i. e., tropism behavior, schooling behavior, association behavior, feeding behavior, and vertical movement pattern. The related main research methods currently in use were introduced, and the issues on this subject needed to be paid great attention to were discussed.

[Age identification and growth characteristics of Katsuwonus pelamis in western and central Pacific Ocean].

Fish age and growth are the important biological parameters for the assessment of fishery resources. With the help of purse seiners, 262 individuals of skipjack tuna (Katsuwonus pelamis) were sampled from western and central Pacific Ocean in October 2007 - January 2008. The measurements in situ showed that the fork length of the samples ranged from 278 to 746 mm, and their body mass ranged from 345 to 9905 g. The first dorsal spine of each individual was collected for age identification and growth parameters estimation. The relationship between fork length (L, mm) and body mass (M, g) was expressed as M = 3.612 x 10(-6) L3.278 (R2 = 0.9782), and no significant difference was found for the males and females (F = 2.002, P > 0.05). A comparison with Akaike information criterion (AIC) suggested that among power regression equation, linear regression equation, and exponential regression equation, linear regression equation was most suitable for describing the relationship between fork length and spine radius (AIC = 2257.4). The mean back-calculated fork lengths of K. pelamis with the ages of 1-5 estimated by Fraser-Lee's method were 398.4, 494.2, 555.4, 636.8, and 728.8 mm, respectively. Residual analyses indicated that there was no significant difference in the growth of male and female K. pelamis (F = 0.670; df = 182; P > 0.05). The sex-combined von Bertalanffy growth equation of K. pelamis was L(t) = 706.51 (1 - e(-0.64(t + 0.037))).

[Electrophysiological effects of antiarrhythmic drugs on pacemaker cells in guinea pig left ventricular outflow tract].

OBJECTIVE: To explore the electrophysiological effects of antiarrhythmic drugs on pacemaker cells of left ventricular outflow tract. METHODS: By using conventional intracellular microelectrode technique to record action potentials, series antiarrhythmic drugs were used to investigate the electrophysiological features and regularities of spontaneous activity of left ventricular outflow tract. RESULTS: (1) Perfusion with 1 micromol/L quinidine resulted in a significant decrease in rate of pacemaker firing (RPF, P < 0.05), velocity of diastolic depolarization (VDD, P < 0.05), amplitude of action potential (APA, P < 0.05), and maximal rate of depolarization (V(max), P < 0.05), and a marked prolonging in 50% and 90% of duration of action potential (APD50 and APD90, P < 0.05). (2) 1 micromol/L lidocaine decreased RPF, VDD, MDP, APA and V(max) significantly (P < 0.05), shortened APD50 and APD90 notably (P < 0.05). (3) 1 micromol/L propafenone led to a significant decrease in RPF (P < 0.01), VDD (P < 0.05), APA (P < 0.05), V(max) (P < 0.01), and a marked prolonging in APD50 (P < 0.01) and APD90 (P < 0.05). (4) Application of 5 micromol/L propranolol resulted in a significant decrease in RPF and VDD (P < 0.01), MDP and APA (P < 0.01), V(max) (P < 0.05) and a notable prolonging in APD50 and APD90 (P < 0.05). (5) Perfusion with 1 micromol/L amiodarone resulted in a significant decrease in RPF and VDD (P < 0.01), APA (P < 0.01), V(max) (P < 0.05), a marked prolonging in APD50 (P < 0.01) and APD90 (P < 0.05). (6) 1 micromol/L verapamil significantly decreased RPF and VDD (P < 0.01), MDP and APA (P < 0.05), V(max) (P < 0.05), notably prolonged APD50 and APD90 (P < 0.01). (7) 50 micromol/L adenosine significantly decreased RPF and VDD (P < 0.05), APA (P < 0.05), V(max) (P < 0.01), markedly shortened APD50 and APD90 (P < 0.05). CONCLUSION: All kinds of antiarrhythmic drugs can decrease the autorhythmicity of guinea pig left ventricular outflow tract. By altering APD50 and APD90, they can affect effective refractory period (ERP) and having a significant effect on autorhythmicity of left ventricular outflow tract.

[Ecological benefits of planting winter rapeseed in western China].

To evaluate the ecological benefits of popularizing winter rapeseed planting in western China, a wind tunnel simulation test was conducted with four kinds of farmland surface, i.e., winter rapeseed, winter wheat, wheat stubble, and bare field just after spring sowing, collected from west Gansu in April. The results showed that winter rapeseed surface had a roughness of 4.08 cm and a threshold wind velocity as high as 14 m x s(-1), being more effective in blown sand control than the other three surfaces. Under the same experimental conditions, the wind erosion modulus and sand transportation rate of winter rapeseed surface were only 4.1% and 485% of those of the bare field just after spring sowing, and the losses of soil organic matter, alkali-hydrolyzed N, available P and K, catalase, urease, alkaline phosphatase, invertase, and microbes of winter rapeseed surface due to wind erosion were only 1.4%, 5.1%, 1.6%, 2.7%, 9.7%, 3.6%, 6.3%, 6.7% and 1.5% of those of the bare field, respectively. It was suggested that popularizing winter rapeseed planting in west China could control wind erosion, retain soil water and nutrients, increase multicropping index, and improve economic benefits of farmland. In addition, it could benefit the regional desertification control and ecological environment improvement.