BACKGROUND:Cyclin A2 is a key regulator of cellcycle. Location and expression of cyclin A2 in neonatal mouse myocardium is not clear.
OBJECTIVE:To observe the location and expression of cyclin A2 in neonatal mouse cardiomyocytes and its relationship with the exit of cardiomyocytes from cellcycle.
METHODS:Neonatal mice were kil ed to take myocardial tissues at 0, 3, 7, 14 and 28 days after birth. Western blot were used to detect the expression of cyclin A2, proliferating cellnucleus antigen and Phospho-histone H3. Immunohistochemitry detection was used to detect the location of cyclin A2 and expression of proliferation cellnucleus antigen at different time after birth.
RESULTS AND CONCLUSION:Western blot showed the decrease of cyclin A2 after birth til disappeared at day 4 (P=0.001). Cyclin A2 located mainly in the nucleus after birth and exported to the cytoplasm at day 14, and basical y disappeared at day 28. Proliferating cellnucleus antigen showed gradual y decreased tendency after birth. Mitosis specific marker, Phospho-histone H3, exhibited a gradual decrease after birth, which was consistent with cyclin A2 in expression intensity.

Objective To observe the influence of different energy windows of the medium-energy general-purpose(MEGP)collimator on image quality,so as to optimize the energy window of yttrium-90(90Y)bremsstrahlung SPECT imaging.Methods 90Y bremsstrahlung spectrum was acquired,and the sensitivity,percentage of the source counts in useful field of view(S/FOV%)and signal-to-background ratio(S/B)of 90Y bremsstrahlung SPECT imaging at MEGP under different energy windows were compared.Results The energy spectrum of 90Y bremsstrahlung was a continuous curve,with the peak of 76.2 keV with MEGP collimator.The images obtained with MEGP collimator were clear,and no significant differences of S/FOV%nor S/B was found between 10%and 20%window width groups(both P＞0.05),but the sensitivities of the latter was higher than the former(P＜0.05).The sensitivity of 70-90 keV images was relatively high,while the S/FOV%and S/B had decreased.The S/FOV%and S/B of images ranging from 40-60 keV were high,but the sensitivity was low.Images acquired with 100 keV±20%showed fairly high sensitivity,S/FOV%and S/B,which was 69.73%,0.62 and 1.64,respectively.Conclusion When performing 90Y bremsstrahlung SPECT with MEGP collimator,the image quality at 20%window width was better than at 10%window width,and 100 keV±20%showed fairly high sensitivity and not significantly decreased S/FOV%and S/B.

Ossification of the spinal ligaments (OSL) is characterized by the appearance of pathologic bone tissue within the spinal ligamentous tissue. OSL tends to occur in the cervical and thoracic segments with important cause of spinal stenosis. Compression of the spinal cord or nerve roots by ossified masses can lead to severe neurological dysfunction, which has a tremendous impact on the quality of life of patients. However, the exact etiology and pathogenesis of OSL are still unclear. Epigenetic regulation is widespread in organisms and refers to the appearance of heritable changes in gene expression without alteration in genomic DNA sequence. As an important form of biodiversity regulation, epigenetic regulation plays an important role in development of several diseases. Epigenetic regulation has multiple manifestations in OSL, including DNA methylation, histone modifications, and non-coding RNA regulation. Sequencing tools, such as gene microarrays, have revealed significant differences in DNA methylation profiles and non-coding RNA expression between ossified and normal spinal ligaments. These differences can cause abnormal expression of osteogenesis-related target genes through direct or indirect pathways, thus affecting the ossification process of spinal ligaments. In addition, interactions between these epigenetic regulatory mechanisms constitute a large and complex regulatory network. Consequently, an in-depth understanding of the role of different epigenetic regulatory mechanisms and the linkages between them in the initiation and progression stages of OSL is expected to provide a valuable reference for the clinical diagnosis and treatment of OSL-related diseases.