Geographic and Climatic Attributions of Autumn Land Surface Phenology Spatial Patterns in the Temperate Deciduous Broadleaf Forest of China

Autumn vegetation phenology plays a critical role in identifying the end of the growing season and its response to climate change. Using the six vegetation indices retrieved from moderate resolution imaging spectroradiometer data, we extracted an end date of the growing season (EOS) in the temperate deciduous broadleaf forest (TDBF) area of China. Then, we validated EOS with the ground-observed leaf fall date (LF) of dominant tree species at 27 sites and selected the best vegetation index. Moreover, we analyzed the spatial pattern of EOS based on the best vegetation index and its dependency on geo-location indicators and seasonal temperature/precipitation. Results show that the plant senescence reflectance index-based EOS agrees most closely with LF. Multi-year averaged EOS display latitudinal, longitudinal and altitudinal gradients. The altitudinal sensitivity of EOS became weaker from 2000 to 2012. Temperature-based spatial phenology modeling indicated that a 1 K spatial shift in seasonal mean temperature can cause a spatial shift of 2.4–3.6 days in EOS. The models explain between 54% and 73% of the variance in the EOS timing. However, the influence of seasonal precipitation on spatial variations of EOS was much weaker. Thus, spatial temperature variation controls the spatial patterns of EOS in TDBF of China, and future temperature increase might lead to more uniform autumn phenology across elevations

Hyalinizing clear cell carcinoma of salivary gland: a clinicopathological study of 8 cases

Background and purpose: Hyalinizing clear cell carcinoma (HCCC) of salivary gland is a rare tumor with low-grade malignancy, which usually occurs in minor salivary glands. Due to its rarity, the tumor type is not well known to pathologists and misdiagnosis frequently occurred. The aim of this study was to investigate the histologic, immunophenotypic and molecular features of HCCC. Methods: Eight cases of salivary gland HCCC diagnosed at the Department of Pathology, Fudan University Shanghai Cancer Center from January 2015 to October 2019 were collected. Clinicopathologic characteristics were analyzed, and fluorescence in situ hybridization (FISH) assay was used to detect EWSR1 translocation in tumor tissue. Diagnostic criteria and differential diagnosis were summarized, with a review of the literature. Results: All patients were female, aged 26 to 68 years, and the tumor locations included the oral cavity, nasopharynx, parotid gland and other sites of head and neck. Microscopically, the tumors consisted mainly of clear cells and eosinophilic cells with variable proportions, arranged in nests, sheets and trabeculae. In 1 case, the tumor was composed almost entirely of eosinophilic cells; in 6 cases, obvious nuclear pseudo-inclusion bodies were seen; in 1 case, neoplastic cells were connected to the surface squamous epithelium; in 1 case, the glandular structure was seen in some areas of the tumor; in 3 cases, a sheath of lymphocyte was formed around the tumor nests; in 7 cases, there was a sclerosing or hyalinizing stromal reaction, showing desmoplastic changes; and 1 case featured stoma with myxoid changes. There was no definite keratinization or necrosis in all tumors, and mitotic figures were generally rare. Immunohistochemical staining showed that tumor cells of 8 cases were diffusely positive for AE1/AE3 protein, 7 cases expressed P63, and 7 cases focally expressed low molecular weight keratin CK7 or CAM5.2, however, S-100, calponin, PAX-8 and CD10 were all negative. All tumors showed low proliferative activity, with the Ki-67 proliferation index less than 5%. FISH test revealed EWSR1 translocation in all 8 cases. All patients demonstrated no recurrence or metastasis during the follow up ranging 4-50 months. Conclusions: HCCC of salivary gland is a low-grade malignancy occurring mainly in minor salivary glands, with characteristic histological and molecular features. This cancer type needs to be distinguished with many morphologic mimics of salivary gland. Most cases with salivary HCCC feature a good prognosis

Severe Maternal Hyperglycemia Exacerbates the Development of Insulin Resistance and Fatty Liver in the Offspring on High Fat Diet

Background. Adverse maternal environments may predispose the offspring to metabolic syndrome in adulthoods, but the underlying mechanism has not been fully understood. Methods. Maternal hyperglycemia was induced by streptozotocin (STZ) injection while control (CON) rats received citrate buffer. Litters were adjusted to eight pups per dam and then weaned to standard diet. Since 13 weeks old, a subset of offspring from STZ and CON dams were switched to high fat diet (HFD) for another 13 weeks. Glucose and insulin tolerance tests (GTT and ITT) and insulin secretion assay were performed; serum levels of lipids and leptin were measured. Hepatic fat accumulation and islet area were evaluated through haematoxylin and eosin staining. Results. STZ offspring exhibited lower survival rate, lower birth weights, and growth inhibition which persisted throughout the study. STZ offspring on HFD showed more severe impairment in GTT and ITT, and more profound hepatic steatosis and more severe hyperlipidemia compared with CON-HFD rats. Conclusions. Offspring from diabetic dams would be prone to exhibit low birth weight and postnatal growth inhibition, but could maintain normal glucose tolerance and insulin sensitivity. HFD accelerates development of insulin resistance in the offspring of diabetic dams mainly via a compensatory response of islets

High-Resolution 3D Heart Models of Cardiomyocyte Subpopulations in Cleared Murine Heart

Biological tissues are naturally three-dimensional (3D) opaque structures, which poses a major challenge for the deep imaging of spatial distribution and localization of specific cell types in organs in biomedical research. Here we present a 3D heart imaging reconstruction approach by combining an improved heart tissue-clearing technique with high-resolution light-sheet fluorescence microscopy (LSFM). We have conducted a three-dimensional and multi-scale volumetric imaging of the ultra-thin planes of murine hearts for up to 2,000 images per heart in x-, y-, and z three directions. High-resolution 3D volume heart models were constructed in real-time by the Zeiss Zen program. By using such an approach, we investigated detailed three-dimensional spatial distributions of two specific cardiomyocyte populations including HCN4 expressing pacemaker cells and Pnmt(+) cell-derived cardiomyocytes by using reporter mouse lines Hcn4(DreER/tdTomato) and Pnmt(Cre/ChR2−tdTomato). HCN4 is distributed throughout right atrial nodal regions (i.e., sinoatrial and atrioventricular nodes) and the superior-inferior vena cava axis, while Pnmt(+) cell-derived cardiomyocytes show distinct ventral, left heart, and dorsal side distribution pattern. Our further electrophysiological analysis indicates that Pnmt + cell-derived cardiomyocytes rich left ventricular (LV) base is more susceptible to ventricular arrhythmia under adrenergic stress than left ventricular apex or right ventricle regions. Thus, our 3D heart imaging reconstruction approach provides a new solution for studying the geometrical, topological, and physiological characteristics of specific cell types in organs

Arctic warming-induced cold damage to East Asian terrestrial ecosystems

The global mean temperature is increasing due to the increase in greenhouse gases in the atmosphere, but paradoxically, many regions in the mid-latitudes have experienced cold winters recently. Here we analyse multiple observed and modelled datasets to evaluate links between Arctic temperature variation and cold damage in the East Asian terrestrial ecosystem. We find that winter warming over the Barents-Kara Sea has led to simultaneous negative temperature anomalies over most areas in East Asia and negative leaf area index anomalies in southern China where mostly subtropical evergreen forests are growing. In addition to these simultaneous impacts, spring vegetation activity and gross primary productivity were also reduced over evergreen and deciduous trees, and spring phenological dates are delayed. Earth System model simulations reveal that cold damage becomes stronger under greenhouse warming; therefore Arctic warming-induced cold stress should be considered in forest and carbon management strategies

Single-cell RNA sequencing of murine hearts for studying the development of the cardiac conduction system

The development of the cardiac conduction system (CCS) is essential for correct heart function. However, critical details on the cell types populating the CCS in the mammalian heart during the development remain to be resolved. Using single-cell RNA sequencing, we generated a large dataset of transcriptomes of ~0.5 million individual cells isolated from murine hearts at six successive developmental corresponding to the early, middle and late stages of heart development. The dataset provides a powerful library for studying the development of the heart's CCS and other cardiac components. Our initial analysis identified distinct cell types between 20 to 26 cell types across different stages, of which ten are involved in forming the CCS. Our dataset allows researchers to reuse the datasets for data mining and a wide range of analyses. Collectively, our data add valuable transcriptomic resources for further study of cardiac development, such as gene expression, transcriptional regulation and functional gene activity in developing hearts, particularly the CCS

Effects of Wenxin Keli on the Action Potential and L-Type Calcium Current in Rats with Transverse Aortic Constriction-Induced Heart Failure

Objective. We investigated the effects of WXKL on the action potential (AP) and the L-type calcium current (ICa-L) in normal and hypertrophied myocytes. Methods. Forty male rats were randomly divided into two groups: the control group and the transverse aortic constriction- (TAC-) induced heart failure group. Cardiac hypertrophy was induced by TAC surgery, whereas the control group underwent a sham operation. Eight weeks after surgery, single cardiac ventricular myocytes were isolated from the hearts of the rats. The APs and ICa-L were recorded using the whole-cell patch clamp technique. Results. The action potential duration (APD) of the TAC group was prolonged compared with the control group and was markedly shortened by WXKL treatment in a dose-dependent manner. The current densities of the ICa-L in the TAC group treated with 5 g/L WXKL were significantly decreased compared with the TAC group. We also determined the effect of WXKL on the gating mechanism of the ICa-L in the TAC group. We found that WXKL decreased the ICa-L by accelerating the inactivation of the channels and delaying the recovery time from inactivation. Conclusions. The results suggest that WXKL affects the AP and blocked the ICa-L, which ultimately resulted in the treatment of arrhythmias