Activity of salivary glands in secreting honey‐elaborating enzymes in two subspecies of honeybee (Apis mellifera L)

The activity of invertase, glucose oxidase and amylase in the cephalic (post‐cerebral) and thoracic salivary glands is determined in Egyptian and Carniolan honeybees (Apis mellifera L). For this purpose, three ages of worker bees are selected for enzyme assays. The results show that the three target enzymes are detected in the two glands during the three worker ages, except invertase, which cannot be detected in the cephalic gland of newly emerged bees of both subspecies. In both glands, the secretion of invertase is highest, followed by amylase and then glucose oxidase. In Carniolan bees, invertase secretion of the cephalic and thoracic glands increases gradually with age. In Egyptian bees, invertase increases with age only in the cephalic gland, whereas, in the thoracic gland, the highest secretion activity is detected in 10–15‐day‐old bees. The highest amounts of glucose oxidase and amylase in the cephalic gland are detected in newly emerged individuals of both Egyptian and Carniolan bees. In the thoracic gland, however, the highest activity of both enzymes is recorded only in newly emerged Egyptian bees. The results are discussed in the light of bee management and biological aspects of the two subspecies.     

Direct observation of toxic effects of cyanobacterial extracellular products on Daphnia

The filtrate from a suspension of the cyanobacterium Anabaena minutissima var. attenuata depressed thoracic limb beat frequency of Daphnia carinata by 38–45% in a food-free medium. Repeated exposure to the filtrate produced a similar depression of activity with full or neary full recovery. Response time to the filtrate was 5–8 min and recovery time was 8–12 min. The dose effect on limb beat frequency was continuous, linear, correlated with increased concentration and with no threshold. There was no relationship between body length and limb beat frequency.The interaction between toxicity and food concentration was tested using the diatom Cyclotella suspended in Anabaena filtrate. Daphnia limb beat frequency was depressed by 62%.     

酸中毒条件下脓毒性休克大鼠胸主动脉对多巴胺反应性的变化

目的:观察不同酸中毒条件下正常大鼠和脓毒性休克大鼠胸主动脉对多巴胺反应性的变化。方法:采用离体血管灌流方法,观察对照组和脓毒性休克组大鼠胸主动脉在不同pH条件下的反应性变化。结果:pH值依次降低,对照组及脓毒性休克组离体胸主动脉对多巴胺反应性均下降,在相同pH值条件下脓毒性休克组比对照组离体血管对多巴胺反应性下降更为明显。结论:①环境pH值的下降会导致正常大鼠和脓毒性休克大鼠离体动脉对多巴胺反应性的下降。②在相同的酸性环境中脓毒性休克大鼠的血管对多巴胺刺激的反应性更差,更易失去活性。     

The influence of contact guidance on the orientation of colonies of subcultured vascular smooth muscle cells

Summary Subcultures of smooth muscle cells derived from rat thoracic aorta were grown on plane plastic substrata and on plastic substrata having ridges molded in them by a heated, ruled template. The cells were found to have a very high degree of contact guidance when distributed sparsely on the ridged substrata. When the cell density increased multilayered, elongated colonies formed. On plane substrata these were irregular, curved, and disposed in all directions. On the ridged substrata, however, the colonies were straight, evenly spaced, and positioned at right angles to the ridges. Supported by Grant MT1011 from the Medical Research Council of Canada.     

Conformationally altered aortic myosin light chains

Aorta smooth myosin contains two types of light chain, LC20 and LC17, which fold together with the N-terminal region of each heavy chain to form the globular head region of myosin. We demonstrate an altered conformation of LC20 after its separation from heavy chain by high concentrations of urea, on the basis of the following evidende: 1) A polyclonal antibody against LC20 was not able to recognize this conformationally altered form; 2) Myosin reconstituted from heavy chains and urea-dissociated light chains exhibited extremely low ATPase activity. Circular dichroism unfolding profiles showed that light chains dissociated from heavy chains by SDS appeared to be more stable than those generated by urea dissociation.     

Extracellular-Purine Metabolism in Blood Vessels (Part I). Extracellular-Purine Level in Blood of Patients with Abdominal Aortic Aneurysm

Adenosine and adenosine derivatives are the main regulators of purinoceptors (P1 and P2) mediated hemostasis and blood pressure. Since impaired hemostasis and high blood pressure lead to atherosclerosis and to the development of aneurysm, in this study we tested and compared the concentration of extracellular purines (e-purines) in the blood in of patients having abdominal aortic aneurysm with that from healthy volunteers. Whereas adenine nucleosides and nucleotides level in human blood plasma was analysed using reverse phase high performance liquid chromatography (HPLC), cholesterol concentration was estimated by an enzymatic assay. We did not find any correlation between e-purines concentration and the age of healthy volunteers. Furthermore, the sum level of e-purines (ATP, ADP, AMP, adenosine, and inosine) in the control group did not exceed 70 μM, while it was nearly two-fold higher in the blood of patients having abdominal aortic aneurysm, (123 μM). In a special case of people with Leriche Syndrome, a disease characterized by deep atherosclerotic changes, the e-purines level had further increased. Additionally, we also report typical atherosclerotic changes in the aorta using histological assays as well as total cholesterol rise. The significant rise in cholesterol concentration in the blood of the patients with abdominal aortas aneurysm, compared with the control groups, was not unique since 23% of the healthy people also exceeded the normal level of cholesterol. Therefore, our results strongly indicate that the estimation of e-purines concentration in the blood may serve as another indicator of atherosclerosis and warrant further consideration as a futuristic diagnostic tool.     

Synthesis,docking study and relaxant effect of 2-alkyl and 2-naphthylchromones on rat aorta and guinea-pig trachea through phosphodiesterase inhibition

Chromone (4), which form the base structure of various flavonoids isolated as natural products, is capable of relaxing smooth muscle. This is relevant to the treatment of high blood pressure, asthma and chronic obstructive pulmonary disease. The former disorder involves the contraction of vascular smooth muscle (VSM), and the latter two bronchoconstriction of airway smooth muscle (ASM). One of the principal mechanisms by which flavonoids relax muscle tissue is the inhibition of phosphodiesterases (PDEs), present in both VSM and ASM. Therefore, a study was designed to analyze the structure–activity relationship of chromone derivatives in vaso- and bronchorelaxation through the inhibition of PDE. Docking studies showed that these chromones bind at the catalytic site of PDEs. Consequently, we synthesized analogs of chromones substituted at position C-2 with alkyl and naphthyl groups. These compounds were synthesized from 2-hydroxyacetophenone and acyl chlorides in the presence of DBU and pyridine, modifying the methodology reported for the synthesis of 3-acylchromones by changing the reaction temperature from 80 to 30 °C and using methylene chloride as solvent, yielding the corresponding phenolic esters 10a–10h. These compounds were cyclized with an equivalent of DBU, pyridine as solvent, and heated at reflux temperature, yielding the chromones 11a–11h. Evaluation of the vasorelaxant effect of 4, 11a–11h on rat aorta demonstrated that potency decreases with branched alkyl groups. Whereas the EC₅₀ of compound 11d (substituted by an n-hexyl group) was 8.64 ± 0.39 μM, that of 11f (substituted by an isobutyl group) was 14.58 ± 0.64 μM. Contrarily, the effectiveness of the compound is directly proportional to the length of the alkyl chain, as evidenced by the increase in maximal effect of compound 11c versus 11d (66% versus 100%) and 11e versus 11f (60% versus 96%). With an aromatic group like naphthyl as the C-2 substituent, the effectiveness was only 43%. All compounds tested on guinea pig trachea showed less than 55% effectiveness. Compounds 4, 11a–11h were evaluated as PDE inhibitors in vitro, with 11d showing the greatest effect (73%), corroborating the importance of a long alkyl chain, which inhibits the decomposition of cGMP. Docking studies showed that the compound 11d was selective for the inhibition of PDE-5.     

Atrial fibrillation after thoracic surgery for lung cancer: use of a single cut-off value of N-terminal pro-B type natriuretic peptide to identify patients at risk

Postoperative atrial fibrillation (AF) is a well-known complication occurring after thoracic surgery. B-type natriuretic peptide has recently been investigated as a predictive marker of postoperative AF after cardiac surgery. The aim of this study was to evaluate a definite cut-off for N-terminal pro-B type natriuretic peptide (NT-proBNP) in predicting postoperative AF in lung cancer patients. NT-proBNP was determined before and after surgery in 400 patients. Cardiac function was monitored by continuous postoperative ECG and clinical cardiological evaluation. AF occurred in 18% of the patients. Receiver operating characteristic curve analyses identified a cut-off of 182.3?ng l^?1 as the one with the highest sensitivity and specificity. Perioperative increased levels of NT-proBNP seem to predict postoperative AF in patients undergoing thoracic surgery, and a single cut-off of 182.3?ng l^?1 can be used to select high-risk patients who could receive preventive therapy, leading to a considerable decrease in the total costs associated with the management of this complication.     

Ethanol disrupts the formation of hypochord and dorsal aorta during the development of embryonic zebrafish

It has been demonstrated that maternal drinking during pregnancy had serious adverse effects on the health of the newborns. Fetal alcohol syndrome (FAS) is the most important developmental abnormality caused by maternal alcohol abuse during pregnancy. Clinically, it is characterized by head and facial ab-normalities, cardiovascular malformation, and perma-nent nervous system damage[1,2]. A lot of experimental models have been developed to study the ethanol’s effects on embryonic development,…     

Fiber micro-architecture in the longitudinal-radial and circumferential-radial planes of ascending thoracic aortic aneurysm media

It was recently demonstrated by our group that the delamination strength of ascending thoracic aortic aneurysms (ATAA) was lower than that of control (CTRL, non-aneurysmal) ascending thoracic aorta (ATA), and the reduced strength was more pronounced among bicuspid (BAV) vs. tricuspid aortic valve (TAV) patients, suggesting a different risk of aortic dissection for BAV patients. We hypothesized that aortic valve morphologic phenotype predicts fiber micro-architectural anomalies in ATA. To test the hypothesis, we characterized the micro-architecture in the longitudinal-radial (Z-RAD) and circumferential-radial (Θ-RAD) planes of human ATA tissue that was artificially dissected medially. The outer and inner-media of CTRL-ATA, BAV-ATAA and TAV-ATAA were imaged using multi-photon microscopy in the Z-RAD and Θ-RAD planes to observe collagen and elastin. Micrographs were processed using an image-based tool to quantify several micro-architectural characteristics. In the outer-media of BAV-ATAA, elastin was more undulated and less aligned about the Θ-axis when compared with CTRL-ATA, which is consistent with increased tensile stretch at inflection point of Θ-strips of adventitial-medial half of BAV-ATAA (1.28) when compared with CTRL-ATA (1.13). With increasing age, collagen became more undulated about the Z-axis within the outer-media of TAV-ATAA, and elastin became more oriented in the Z-axis and collagen less radially-oriented within the inner-media of TAV-ATAA. This discrepancy in the micro-architecture with fibers in the inner layers being more stretched and with disrupted radially-oriented components than fibers in the outer layers may be associated with the development, progression and vascular remodeling in aneurysms arising in TAV patients.