CT assessment of the increased density of cerebral vessels in plateau region.

In this study, the relationship between the brain parenchymal density, the cerebral vessel density, the mean corpuscular hemoglobin (MCH) content, the mean corpuscular hemoglobin concentration (MCHC), and the morbidity associated with lacunar infarction of residents living in either the plains or the plateau regions were analyzed and compared for their potential clinical implications. Clinical data from the brain CT scans of individuals living in either the plain or plateau regions (129 each) were collected. Specifically, the CT values for basal ganglia, the middle cerebral artery, and the superior sagittal sinus, along with the number of patients with lacunar infarction, were collected. In addition, the MCH and MCHC values were measured in blood samples collected within 48 h following the CT scans. For statistical analysis, an independent sample t-test, Pearson's correlation test (permutation test), and Chi-squared test were employed. The inhabitants of the plateau had a significantly higher CT value of basal ganglia, the middle cerebral artery, and superior sagittal sinus and also higher levels of MCH and MCHC in the blood (ps < 0.001) than the inhabitants of the plains region. Further, there was a significant positive correlation between the three aforementioned CT values and the MCH and MCHC findings. However, no significant differences were found in the morbidity of lacunar infarction between these two regions (p > 0.05). The inhabitants in the plateau have a significantly higher brain parenchymal density, higher CT value for cerebral vessels density, and higher blood MCH and MCHC levels in comparison with individuals occupying the plains. Concurrently, the parenchymal density and the CT values are shown to be positively correlated with the MCH and MCHC content in the blood.

Microsatellite markers for the cushion rock jasmine, Androsace tapete (Primulaceae), a species endemic to the Qinghai-Tibetan Plateau.

PREMISE OF THE STUDY: Microsatellite markers were developed in an alpine plant endemic to the Qinghai-Tibetan Plateau, Androsace tapete, to investigate its spatial genetic structure, gene flow, and mating patterns. • METHODS AND RESULTS: Using the combined biotin capture method, 16 microsatellite primer sets were isolated and characterized. Fifteen of these markers showed polymorphism, and the number of alleles per locus ranged from three to 13 across 56 individuals from six Tibetan populations. • CONCLUSIONS: These markers provide a useful tool to investigate the spatial genetic structure, gene flow, and mating system of A. tapete.

Fine- and landscape-scale spatial genetic structure of cushion rockjasmine, Androsace tapete (Primulaceae), across southern Qinghai-Tibetan Plateau.

The cushion rockjasmine, Androsace tapete (Primulaceae), is among the angiosperms with highest altitudal distribution in the world. Cushion rockjasmine is a prominent pioneer species in alpine deserts and alpine flowstone slope habitats up to 5,300 m on Qinghai-Tibetan Plateau. In this study, we use inter simple sequence repeat (ISSR) markers to investigate the spatial genetic structure of A. tapete at both fine-scale and landscape-scale, with emphasis on testing the hypothesis that the low-altitude valley of the Brahmaputra River, running from west to east across Qinghai-Tibetan Plateau, has significant effects on the spatial population structure of A. tapete. A total of 235 individuals were collected from five populations in disjunct ridges (i.e. two populations located in the north, and three in the south of the Brahmaputra River), including 158 individuals that were spatial explicitly sampled from a 30 m x 90 m plot. At fine scale, spatial autocorrelation analysis indicates a significant genetic structure within a short distance (less than 10 m), which is probably due to limited gene dispersal via pollen and/or seeds. At landscape scale, however, AMOVA suggests that most of the total genetic variation (85%) is among individuals within populations; and the Brahmaputra River plays a weak role in shaping the spatial population structure of A. tapete. In addition, the results of PCA and STRUCTURE assignment show significant genetic associations between the populations across the Brahmaputra River. The historical gene exchanges and slow genetic drift may be responsible for the lack of deep genetic differentiation among topographically separated populations in A. tapete.