Methyl farnesoate induced ovarian maturation in the spider crab,Libinia emarginata

Summary

To overcome the problem of getting crustaceans to reproduce in captivity, eyestalk ablation or X-organ sinus gland removal is commonly utilized in commercially important species such as shrimp. We have investigated the effect of unilateral and bilateral eyestalk ablation on methyl farnesoate (MF) production by mandibular organs (MOs) and on ovarian maturation in female spider crabs Libinia emarginata, a useful model since these animals are in a terminal molt and are devoid of a functional Y-organ. Non-reproductive, over-wintering female L. emarginata were induced to be reproductive by feeding and increasing the holding temperature to stimulate the endocrine system. In addition, we removed X-organ sinus glands by eyestalk ablation either unilaterally (UEA) or bilaterally (BEA) to further stimulate MF synthesis by MOs. Endogenous MF in the hemolymph was extracted and quantified by means of HPLC and in some cases by GC/MS. Oocyte growth and egg quality were studied simultaneously to determine how they were related to MF levels found during vitellogenesis. The initial MF concentration in unablated controls was low, 0.31 ng/ml of hemolymph, and this increased (p<0.05) to about 1 ng/ml by 2 weeks, remaining at about that level for the remainder of the experiment. Eyestalk ablation significantly stimulated MF concentrations by week 1 to nearly 2 and 3.5ng/ml in the UEA (p <0.01) and BEA (p <0.001) animals, respectively. Oocytes appeared to respond to increased MF levels, as ovarian maturation was initiated from the point at which MF increased (p <0.05). Thereafter, the rate of oocyte growth was directly correlated with the extent of elevation of MF. The gonado-somatic index [(GSI) = gonad weight/body weight × 100] of controls at the start was about 1.5 and increased to 6.5 by week 4. Mature oocytes were reached at a GSI around 7. Oocyte maturation was accomplished at week 2 in BEA, week 3 in UEA, and later than week 4 in controls. After maturation, oocytes started to degrade in some ablated animals, particularly in the bilaterally ablated ones where the highest MF concentrations were observed. These data indicate that MF elevations are required for stimulating ovarian maturation in Crustacea. MF appears to accelerate gonad development during the vitellogenic process, but may be deleterious at high concentrations. These results have a significant and important application and implications for aquaculture.     

A 24-HOUR AMBULATORY ECG MONITORING IN ASSESSMENT OF QT INTERVAL DURATION AND DISPERSION IN ROWERS WITH PHYSIOLOGICAL MYOCARDIAL HYPERTROPHY

Myocardial hypertrophy (MH) due to cardiac pathology is characterized by an increase in QT interval duration and dispersion, while the findings for exercise-induced myocardial hypertrophy are contradictory. The majority of published research findings have not explored this relationship, but there have only been a few conducted studies using 24-hour ECG monitoring. The aim of the study was to determine the QT interval duration and dispersion in short-term and 24-hour ECG in endurance athletes with myocardial hypertrophy and without it. Methods: A total of 26 well-trained rowers underwent a resting 12-lead ECG, 24-hour ECG monitoring and echocardiography. Results: Athletes with MH (n = 7) at rest did not show any increase in QTc interval duration and dispersion, or mean and maximal QTc duration in Holter monitoring compared to athletes without MH (n = 19). Left ventricular mass was not significantly correlated with any QTc characteristics. Furthermore, athletes with MH had significantly longer mean QT (P = 0.01) and maximal QT (P = 0.018) intervals in Holter monitoring and higher 24-hour heart rate variability indexes due to stronger vagal effects. Conclusions: The present study demonstrated that athlete''s heart syndrome with myocardial hypertrophy as a benign phenomenon does not lead to an increase in QT interval duration, or increases in maximal and mean duration in a 24-hour ECG. An increase in QT interval duration in athletes may have an autonomic nature.     

Anatomic Twist to a Straightforward Ablation

Atrioventricular (AV) junction ablation for treatment of refractory atrial fibrillation is a well defined, standardized procedure and the simplest of commonly performed radiofrequency ablations in the field of cardiac electrophysiology. We report successful AV junction ablation using an inferior approach in a case of inferior vena cava interruption. Inability during the procedure to initially pass the ablation catheter into the right ventricle, combined with low amplitude electrograms, led to suspicion of an anatomic abnormality. This was determined to be a heterotaxy syndrome with inferior vena cava interruption and azygos continuation, draining in turn into the superior vena cava. Advancing Schwartz right 0 (SRO) sheath through the venous abnormality into the right atrium allowed adequate catheter stability to successfully induce complete AV block with radiofrequency energy.     

A computational method for developing hierarchical large deformation viscoelastic models of the contracting heart

In this study, a new computational method for modelling the contracting heart is described. Using this method, the cardiac wall is constructed from basic, repeating contractile units that represent individual myocardial units and collagen, each with its own set of parameters, including orientation, passive and active behaviour and stimulation propagation. The method allows individual control of each structural unit (e.g. at the level of a single myocardial unit). Feasibility of modelling dynamic heart contraction using this method is demonstrated using 2D cross-sections and simplified 3D geometries. Effects of non-contractile scar and myopathic tissue were also tested in these geometrical configurations. Results from the 2D and 3D simulations were, overall, in agreement with well-established physiological data. The present method holds promise for modelling complex heart pathologies, abnormal mechanical properties (e.g. myocardial infarcts) and electrical conduction properties (branch blocks), and their spatial distributions across the myocardial tissues.     

Changes in kidney tissue and effects of erythropoietin after acute heart failure

Impairment of cardiac function causes renal damage. Renal failure after heart failure is attributed to hemodynamic derangement including reduced renal perfusion and increased venous pressure. One mechanism involves apoptosis and is defined as cardiorenal syndrome type 1. Erythropoietin (EPO) is a cytokine that induces erythropoiesis under hypoxic conditions. Hypoxia inducible factor 1 alpha (HIF-1α) plays a regulatory role in cellular response to hypoxia. Protective effects of EPO on heart, kidney and nervous system are unrelated to red blood cell production. We investigated early changes in and effects of EPO on renal tissues of rats with myocardial infarction by morphology and immunohistochemistry. Coronary artery ligation was used to induce myocardial infarction in Wistar rats. Group 1 comprised sham operated rats; groups 2, 3 and 4 included rats after coronary artery ligation that were sacrificed 6 h after ligation and that were treated with saline, 5,000 U/kg EPO or 10,000 U/kg EPO, respectively; group 5 included rats sacrificed 1 h after ligation. Group 2 showed increased renal tubule damage. Significantly less tubule damage was observed in EPO treated groups. EPO and EPO receptor (EPO-R) immunostaining intensities increased slightly for group 5 and became more intense for group 2. EPO and EPO-R immunostaining was observed in the interstitial area, glomerular cells and tubule epithelial cells of EPO treated groups. HIF-1α immunostaining was observed in collecting tubules in the medulla only in group 2. Caspase-3 immunostaining is an indicator of apoptosis. Caspase-3 staining intensity decreased in renal medulla of EPO treated groups. EPO treatment may exert a protective effect on the renal tissues of patients with cardiorenal syndrome.     

Synergistic effects of olfactory and tactile cues in short‐range mate finding of Ophraella communa

Sensory signals between individuals are important in short‐range mate finding. The purpose of our experiments was to verify the roles of different sensory cues in mate orientation and discrimination in Ophraella communa LeSage (Coleoptera: Chrysomelidae) adults. Sex discrimination and sensory deprivation tests (i.e., depriving the olfactory and/or visual senses of either or both sexes by coating with paint) were conducted in the laboratory. Male O. communa were able to locate and recognize conspecifics using olfactory cues prior to physical contact, but could not discriminate the opposite sex prior to physical contact. When the olfaction of male O. communa was deprived by painting antennae, males spent significantly longer times seeking mates in the arena. Copulation duration did not differ significantly among treatments. Thus, the mating process of O. communa adults was mediated by contact cues, but not by olfactory cues. The percentages of successful mating, searching duration, and copulation duration were all unaffected by visual deprivation, i.e., when the eyes of either or both sexes were covered by black paint. The function of visual cues was thus negligible in the mate‐finding process of O. communa adults. Overall, these results suggested that orientation and discrimination of the opposite sex by O. communa is dependent on the synergy between olfactory and tactile cues.     

竹节参对力竭运动大鼠心肌线粒体ATP酶活性的影响

目的：探讨竹节参对力竭运动大鼠心肌线粒体ATP酶活性的影响。方法：建立力竭运动大鼠模型,测定心肌线粒体ATP酶的活性,研究竹节参对大强度耐力训练大鼠心肌线粒体的保护作用。结果：力竭运动引起大鼠心肌线粒体ATPase（Na＋,K＋-ATPase和Ca2＋-ATPase）活性显著下降,而运动加药组Ca2＋-ATPase有显著升高,Na＋,K＋-ATPase也有明显升高,且ATPase活性均接近于安静对照组的水平。结论：竹节参可提高力竭运动大鼠心肌线粒体内Na＋,K＋-ATP酶和Ca2＋-ATP酶的活性,提示其具有保护线粒体的作用。