Pathological and biochemical analysis of dilated cardiomyopathy of broiler chickens - An animal model

Forty-seven birds (M/F=33/14) with natural outbreak dilated cardiomyopathy (DCM) of right ventricle (RV) and 33 birds with artificially cool-induced DCM hearts were studied. Clinically, 20 severe and 13 mild DCM cases were induced during five weeks and the peak morbidity was in the 2nd week. The progressive dilatation of RV and hypokinesis of septum was shown by echocardiography. At autopsy, the ratio of heart weights to the body weights was increased, the ratio of RV weight to the total ventricle significantly increased, especially in the severe DCM cases (P<0.05). The RV was dilated and the wall thickness was increased and finally both RV and left ventricle (LV) were markedly dilated and the septum became thinner. The struts, weave and coil demonstrated by silver impregnation stain were fragmented, dissociated and overstretched. The promatrix metalloproteinases (MMP)-2, -9 and active MMP-2 were markedly increased in natural outbreak DCM cases, especially in the RV (P<0.05). The proMMP-2 and active MMP-2 was increased in the cool induced DCM cases, especially in the RV of severe DCM (P<0.05). These indicated that both the natural outbreak and the artificially induced DCM of broiler chickens are ideal DCM animal models

Parametric identification of asymmetric buildings from earthquake response records

This paper aims to evaluate the modal frequencies, damping ratios and mode shapes of an asymmetric building, modeled as general torsionally coupled buildings using a modified random decrement method together with the Ibrahim time domain technique based only on few floor acceleration response records from earthquakes. It is not necessary to measure earthquake excitation input. The general relationship between the reduced random decrement signature and the true free vibration response is derived analytically. Because only partial floor response measurements are used, a mode shape interpolation technique is developed to estimate the mode shape values for the locations without measurement, such that all floor responses can be obtained. The results were obtained from simulation data from a five-story building under the 1940 El Centro earthquake and actual records from a seven-story RC school building in north-eastern Taiwan, due to an earthquake near the building site. The results show that the proposed system identification technique is capable of identifying structural dominant modal parameters and responses accurately even with highly coupled modes and high levels of noise contamination

Gene expression analysis in LLC-PK1 renal tubular cells by atrial natriuretic peptide (ANP): correlation of homologous human genes with renal response

We used human DNA microarray to explore the differential gene expression profiling of atrial natriuretic peptide (ANP)-stimulated renal tubular epithelial kidney cells (LLC-PK1) in order to understand the biological effect of ANP on renal kidney cell's response. Gene expression profiling revealed 807 differentially expressed genes, consisting of 483 up-regulated and 324 down-regulated genes. The bioinformatics tool was used to gain a better understanding of differentially expressed genes in porcine genome homologous with human genome and to search the gene ontology and category classification, such as cellular component, molecular function and biological process. Four up-regulated genes of ATP1B1, H3F3A, ITGB1 and RHO that were typically validated by real-time quantitative PCR (RT-qPCR) analysis serve important roles in the alleviation of renal hypertrophy as well as other related effects. Therefore, the human array can be used for gene expression analysis in pig kidney cells and we believe that our findings of differentially expressed genes served as genetic markers and biological functions can lead to a better understanding of ANP action on the renal protective system and may be used for further therapeutic application

Impaired IGF-I signalling of hypertrophic hearts in the developmental phase of hypertension in genetically hypertensive rats

Insulin-like growth factor-I (IGF-I) signalling is reported to contribute to the modulation of blood pressure and set survival and hypertrophic responses in cardiac tissue. However, whether IGF-I signalling normally acts in cardiac tissues of hypertensive rats is unknown. In this study, using spontaneously hypertensive rats (SHR) and stroke-prone spontaneously hypertensive rats (SPSHR), both with early blood pressure increases, and Wistar-Kyoto (WKY) rats as controls, we measured the hypertrophic and IGF-I signalling activity changes in rat hearts at 4, 6 and 12 weeks of age. Both SHR and SPSHR were found to have significantly increased blood pressures and ratios of heart- and left ventricle- to body weight at 12 weeks of age. However, IGF-IR and its downstream signalling, including the protein levels of PI3K and phosphorylated Akt, known to maintain physiological cardiac hypertrophy and cardiomyocyte survival, were downregulated. The results of dot blotting showed that cardiac mRNA levels of IGF-I in hypertensive rats were higher than those in controls starting from the age of 4 weeks. This difference suggests the increased ligand IGF-I mRNA levels may be a compensatory response caused by the impaired IGF-I signalling. Moreover, enhanced cardiac cytosolic cytochrome-c, a mitochondria-dependent apoptotic pathway component, tended to occur in both hypertensive rats, although it did not reach a significant level. These findings indicate that impaired IGF-IR signalling occurs at early stages, and it may contribute, at least partially, to the development of hypertension and pathological cardiac hypertrophy and to cardiomyocyte apoptosis at later stages in SHR and SPSHR. Copyright (c) 2005 John Wiley & Sons, Ltd

The effects of acupuncture on cardiac muscle cells and blood pressure in spontaneous hypertensive rats

If acupuncture is able to prevent hypertrophy of the heart, it could therefore prevent the heart from overloading and thus prevent heart failure or sudden death. We therefore studied the effects of acupuncture on blood pressure and cardiac muscle cells. Rats with spontaneous hypertension were divided into three acupuncture treatment groups and one non-treatment group. The treatment groups were classified as sham acupoint, Yanglingquan (GB. 34) and Quchi (LI. 11) groups. The measurements recorded included changes in tail pressure, femoral arterial pressure, left ventricular weight (LVW), whole heart weight (WHW), body weight (BW), LVW/BW and WHW/BW ratios and the size of the cardiac muscle cells. The results showed that femoral arterial pressure of subjects which were needled on the selected points for 3 days dropped. Acupuncture at these two acupoints seemed to improve the condition of hypertension in a short period of time. Significant changes in the femoral arterial pressure were observed in all subjects when they were treated for 6 days. In the two acupoint groups, the LVW/BW and the WHW/BW ratios did not change significantly. Cardiac Muscle cells reduced in size in the Yanglingquan (GB. 34),treatment groups. This indicates that the Yanglingquan (GB. 34) points not only can lower blood pressure, but also prevent hypertrophy of cardiac muscle cells in spontaneous hypertensive rats (SHR). Therefore, acupuncture could be a good treatment modality for hypertension and hypertrophy of the heart