[Reference values for carotid artery intima-media thickness among community adult dwellers in Shenzhen City].

Objective: To establish reference values for carotid intima-media thickness (CIMT) of adult dwellers in Shenzhen City. Methods: The study was conducted based on the Shenzhen heart failure epidemiological survey from 2021 to 2022. In this survey, residents aged 18 years and above in Shenzhen were selected by using a multi-stage stratified random sampling method. General information, cardiovascular disease (CVD) related behavior and carotid ultrasound examination and etc. were collected from the participants. People with CVD factors, a history of atherosclerotic cardiovascular disease, carotid plaque or having no carotid ultrasound examination results were excluded. The parameter regression model based on fractional polynomial was used to establish the reference values of CIMT by age and sex. Results: A total of 2 163 healthy individuals were enrolled in the final analysis, including 576 males (26.6%) and 1 587 females (73.4%). The fractional polynomial regression of the CIMT mean and standard deviation was obtained. For men, the regression was meanCIMT=0.324 7+0.006 9×age and SDCIMT=0.076 9+0.001 2×age. For women, the regression was meanCIMT=0.354 9+0.005 4×age and SDCIMT=0.041 6+0.002 0×age. Conclusion: The age and sex reference values for CIMT of adult people in Shenzhen established in this study could provide the latest reference standards for early screening of subclinical CVD.

Epigenetically mediated spontaneous reduction of NFAT1 expression causes imbalanced metabolic activities of articular chondrocytes in aged mice.

OBJECTIVE: Abnormal metabolic activities of chondrocytes may cause articular cartilage (AC) degradation, but key transcription factors regulating metabolic activities in AC of aging individuals remain unknown. This study aimed to investigate the role of transcription factor NFAT1 in regulating the expression of anabolic and catabolic molecules in AC of aged mice. METHODS: The hip, knee, and shoulder joints of BALB/c mice were harvested at 6, 12, 15, 18, and 24 months of age for histopathological and immunohistochemical (IHC) analyses. Total RNA was isolated from AC for gene expression. Genomic DNA and chromatin were prepared from AC for methylated DNA immunoprecipitation (MeDIP) and chromatin immunoprecipitation (ChIP) assays. RESULTS: NFAT1 expression in AC of mice was significantly decreased after 12 months of age, which was associated with reduced proteoglycan staining, decreased expression of chondrocyte markers, and increased expression of interleukin-1ß. Forced Nfat1 expression in chondrocytes from aged mice significantly reversed the abnormal metabolic activities. ChIP assays confirmed that NFAT1 bound to the promoter of the Acan, Col2a1, Col9a1, Col11a1, Il1b, Mmp13 and Tnfa genes in articular chondrocytes of aged mice. ChIP and MeDIP assays revealed that reduced NFAT1 expression in AC of aged mice was regulated by epigenetic histone methylation at the promoter region and was correlated with increased DNA methylation at introns 1 and 10 of the Nfat1 gene. CONCLUSION: NFAT1 is a transcriptional regulator of multiple anabolic and catabolic genes in AC of aged mice. Epigenetically mediated reduction of NFAT1 expression causes imbalanced metabolic activities of articular chondrocytes in aged mice.

FISH studies reveal the molecular and chromosomal organization of individual telomere domains in tomato.

The molecular and cytological organization of the telomeric repeat (TR) and the subtelomeric repeat (TGR1) of tomato were investigated by fluorescence in situ hybridization (FISH) techniques. Hybridization signals on extended DNA fibres, visualized as linear fluorescent arrays representing individual telomeres, unequivocally demonstrated the molecular co-linear arrangement of both repeats. The majority of the telomeres consisted of a TR and a TGR1 region separated by a spacer. Microscopic measurements of the TR and TGR1 signals revealed high variation in length of both repeats, with maximum sizes of 223 and 1330 kb, respectively. A total of 27 different combinations of TR and TGR1 was detected, suggesting that all chromosome ends have their own unique telomere organization. The fluorescent tracks on the extended DNA fibres were subdivided into four classes: (i) TR-spacer-TGR1; (ii) TR-TGR1; (iii) only TR; (iv) only TGR1. FISH to pachytene chromosomes enabled some of the TR/TGR1 groups to be assigned to specific chromosome ends and to interstitial regions. These signals also provided evidence for a reversed order of the TR and TGR1 sites at the native chromosome ends, suggesting a backfolding telomere structure with the TGR1 repeats occupying the most terminal position of the chromosomes. The FISH signals on diakinesis chromosomes revealed that distal euchromatin areas and flanking telomeric heterochromatin remained highly decondensed around the chiasmata in the euchromatic chromosome areas. The rationale for the occurrence and distribution of the TR and TGR1 repeats on the tomato chromosomes are discussed.

Preparation of tomato meiotic pachytene and mitotic metaphase chromosomes suitable for fluorescence in situ hybridization (FISH).

Fluorescence in situ hybridization (FISH) is an increasingly powerful tool with a variety of applications in both basic and applied research. With excellent genetic, cytogenetic and molecular maps available, the tomato genome provides a good model to benefit from the full potential of FISH. Tomato chromosomes at mitotic metaphase are small and not particularly suitable for high-resolution FISH. In contrast, chromosomes at meiotic pachytene are about 15 times longer, and easier to identify by their differences in chromosome arm lengths and chromomere pattern. We have developed a technique for preparing chromosomal spreads of young pollen mother cells at mid-prophase I which is suitable for FISH. In a first series of experiments, the hybridization patterns of three classes of repetitive DNA sequences were studied in single and multicolour FISH.