Inhibition of cardiac leptin expression after infarction reduces subsequent dysfunction

Leptin is known to exert cardiodepressive effects and to induce left ventricular (LV) remodelling. Nevertheless, the autocrine and/or paracrine activities of this adipokine in the context of post‐infarct dysfunction and remodelling have not yet been elucidated. Therefore, we have investigated the evolution of myocardial leptin expression following myocardial infarction (MI) and evaluated the consequences of specific cardiac leptin inhibition on subsequent LV dysfunction. Anaesthetized rats were subjected to temporary coronary occlusion. An antisense oligodesoxynucleotide (AS ODN) directed against leptin mRNA was injected intramyocardially along the border of the infarct 5 days after surgery. Cardiac morphometry and function were monitored by echocardiography over 11 weeks following MI. Production of myocardial leptin and pro‐inflammatory cytokines interleukin (IL)‐1β and IL‐6 were assessed by ELISA. Our results show that (1) cardiac leptin level peaks 7 days after reperfused MI; (2) intramyocardial injection of leptin‐AS ODN reduces early IL‐1β and IL‐6 overexpression and markedly protects contractile function. In conclusion, our findings demonstrate that cardiac leptin expression after MI could contribute to the evolution towards heart failure through autocrine and/or paracrine actions. The detrimental effect of leptin could be mediated by pro‐inflammatory cytokines such as IL‐1β and IL‐6. Our data could constitute the basis of new therapeutic approaches aimed to improve post‐MI outcome.     

Determination of aflatoxin levels in peanut butter using HPLC and ELISA procedures: Inter-laboratory comparison

Mycotoxin Research - Six laboratories analyzed portions of the same aqueous acetonitrile extracts of three peanut butters for aflatoxin concentrations by an HPLC procedure (using immunoaffinity...     

Performance of polyvoltine silkworm Bombyx mori L. on different mulberry plant varieties

Five cultivated mulberry plant varieties, BSRM‐34, BSRM‐56, BSRM‐57, BSRM‐58 and BSRM‐59, were used to evaluate the effects of plant variety on larval and cocoon characteristics of mulberry silkworm Bombyx mori L. Silkworm larvae undergo their entire larval periods on leaves of mulberry varieties. Different larval characteristics of larval weight, larval length and larval breadth were measured in different growth stages. After rearing, the fifth instar larvae were transferred into a mountage (Chandraki) structure for cocoon rearing for spinning and cocoon production. The cocoons were then harvested and different cocoon characteristics like cocoon weight, shell weight and shell percentage; and other characters like pupal weight and effective rate of rearing were measured. The results showed statistically significant differences among different varieties on larval and cocoon characteristics. The highest performance was observed by feeding the variety BSRM‐34 in respect of the average weight of 10 mature larvae (40.5 g), single mature larval length (7.6 cm) and breadth (1.0 cm), single cocoon weight (1.4 g), shell weight (0.2 g) and pupal weight (1.2 g) while the average performance was recorded by feeding varieties BSRM‐57 and BSRM‐59. The poorest performance was showed by feeding the variety BSRM‐56 (in case of larval characters) and BSRM‐58 (in case of cocoon characteristics). These two varieties also showed the poorest performance for silk yield. Through comparing all the above parameters it was concluded that BSRM‐34 is the best mulberry variety and it is recommended that Bangladeshi farmers adopt that variety for better yield of silk.     

Incidence of spontaneous ovulation and development of the corpus luteum in non-mated dromedary camels (Camelus dromedarius)

The occurrence of spontaneous ovulation in dromedaries was examined in two separate studies including 20 non-lactating, barren and 12 lactating dromedaries, respectively. Lactating camels were milked twice a day with an automatic bucket milking machine. Ovarian activity was monitored by repeated ultrasonography. Blood samples for progesterone were collected daily or two to three times a week. To compare CL development after spontaneous and induced ovulations, ovulation was induced by a GnRH analogue in eight lactating dromedaries. Spontaneous ovulation was observed in one non-lactating camel (1 of 20 camels, 5%; 1 of 70 follicular waves, 1.4%), whereas, spontaneous ovulation was detected more frequently in lactating dromedaries (5 of 12 camels, 41.7%; 13 of 91 follicular waves, 14.3%). In one lactating camel, spontaneous ovulation occurred repeatedly for nine times. There was a significant effect of type of ovulation (spontaneous versus induced, P < 0.05) and day (P < 0.001) on serum progesterone concentration. Mean serum progesterone levels and total progesterone production (AUC) were higher after induced ovulation. Luteal diameter and serum progesterone concentration were positively correlated (r = 0.71, P < 0.001), but there was a significant difference between morphological and functional development of the CL. In dromedaries, morphological development starts earlier, morphological regression starts later and last longer than functional development and regression of the CL. Compared to induced ovulation, functional development of the CL after spontaneous ovulation might be altered but the morphological development is not affected.     

Fluorescent probe partitioning in GUVs of binary phospholipid mixtures: implications for interpreting phase behavior

The phase behavior of membrane lipids is known to influence the organization and function of many integral proteins. Giant unilamellar vesicles (GUVs) provide a very useful model system in which to examine the details of lipid phase separation using fluorescence imaging. The visualization of domains in GUVs of binary and ternary lipid mixtures requires fluorescent probes with partitioning preference for one of the phases present. To avoid possible pitfalls when interpreting the phase behavior of these lipid mixtures, sufficiently thorough characterization of the fluorescent probes used in these studies is needed. It is now evident that fluorescent probes display different partitioning preferences between lipid phases, depending on the specific lipid host system. Here, we demonstrate the benefit of using a panel of fluorescent probes and confocal fluorescence microscopy to examine phase separation in GUVs of binary mixtures of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC)/1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC). Patch and fibril gel phase domains were found to co-exist with liquid disordered (l(d)) domains on the surface of GUVs composed of 40:60 mol% DOPC/DPPC, over a wide range of temperatures (14-25°C). The fluorescent lipid, 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine-N-(7-nitro-2-1,3-benzoxadiazol-4-yl (NBD-DPPE), proved to be the most effective probe for visualization of fibril domains. In the presence of Lissamine(TM) rhodamine B 1,2-dihexadecanoyl-sn-glycero-3-phosphoethanolamine (Rh-DPPE) we were unable to detect fibril domains. This fluorophore also affected the partitioning behavior of other fluorescent probes. Overall, we show that the selection of different fluorescent probes as lipid phase reporters can result in very different interpretation of the phase behavior of DOPC/DPPC mixtures.     

在中国应用垂直波束雷达监测褐飞虱和其他水稻害虫迁飞的可行性

近年来,可用于昆虫迁飞研究且可自动运行的垂直波束雷达(vertical-looking radar,VLR)的发展使得对迁飞性害虫的周年长期自动监测成为可能。本文提供了我们对能否将这种雷达应用于中国的褐飞虱和其他水稻害虫的监测与预测体系以改善其综合治理的可行性研究结果。以往的研究已经表明,这些害虫一般在300—2000m高度迁飞;而我们根据褐飞虱的雷达和射有效截面的计算结果表明,目前使用的3．2cm波长的VLR对褐飞虱个体目标的最大可检测高度仅约240m;虽然建造一部8．8mm波长的VLR即可覆盖褐飞虱迁飞高度的绝大部分,但其造价和维护费用均过于昂贵。为此,一个更可行的解决方案是,以3．2cm波长的VLR作为包括大多数水稻害虫在内的个体较大的迁飞性害虫的监测工具。