[Ewing's sarcoma of central nervous system: a clinicopathological analysis of six cases]

Objective: To investigate the clinicopathological characteristics, pathological diagnosis of Ewing's sarcoma of the central nervous system. Methods: Six cases of Ewing's sarcoma of the central nervous system diagnosed at the First Affiliated Hospital of Nanjing Medical University, Nanjing, China from 2015 to 2022 were collected. The clinical manifestations, histological morphology, immunophenotype and molecular genetics of these cases were analyzed. The related literature was reviewed. Results: There were four males and two females, with a male to female ratio of 2∶1. The onset age was 17-40 years, with a median age of 23 years. All 6 tumors were located in the spinal cord (2 cases of cervical vertebra, 1 case of thoracic vertebra, 2 cases of lumbar vertebra, and 1 case of sacral vertebra). The patients' clinical manifestations were mostly lumbago, weakness and numbness of lower limbs/limbs. In 1 case, the tumor recurred and metastasized to the suprasellar region and the third ventricle. Microscopically, the tumor showed diffuse infiltrative growth. In some cases, the tumor was closely related to the spinal meninges. The tumor cells were arranged in sheet, lobular, thin-rope, and nest-like patterns. Homer-Wright rosette was visible. The tumor cells were small to medium in size, and most of them had scant cytoplasm. A few cells had clear cytoplasm. Some areas were rhabdoid. The tumor cell nuclei showed focal mild pleomorphism. The chromatin was uniform and delicate while the nucleoli were not obvious. Mitosis was commonly seen. The tumor was separated by fibrous connective tissue and may be accompanied by mucinous degeneration. Immunohistochemistry showed that all tumors were positive for CD99, NKX2.2, Fli1, ERG. ATRX, H3K27me3, INI1 and BRG1 were all retained. Immunohistochemical stains for EMA, GFAP and Olig2 were negative. The Ki-67 proliferation index was 30%-70%. EWSR1 break-apart FISH test was positive. Conclusions: Ewing's sarcoma is rare in the central nervous system and needs to be distinguished from a variety of neoplasms with primitive undifferentiated small cell morphology. Immunohistochemistry and molecular genetics may be required for a proper diagnosis.

Genome-wide identification and analysis of the SGR gene family in Cucumis melo L

Chlorophyll (CHL) is present in many plant organs, and its metabolism is strongly regulated throughout plant development. Understanding the fate of CHL in senescent leaves or during fruit ripening is a complex process. The stay-green (SGR) protein has been shown to affect CHL degradation. In this study, we used the conserved sequences of STAY-GREEN domain protein (NP_567673) in Arabidopsis thaliana as a probe to search SGR family genes in the genome-wide melon protein database. Four candidate SGR family genes were identified in melon (Cucumis melo L. Hetao). The phylogenetic evolution, gene structure, and conserved motifs were subsequently analyzed. In order to verify the function of CmSGR genes in CHL degradation, CmSGR1 and CmSGR2 were transiently overexpressed and silenced using different plasmids in melon. Overexpression of CmSGR1 or CmSGR2 induced leaf yellowing or fruit ripening, while silencing of CmSGR1 or CmSGR2 via RNA interference delayed CHL breakdown during fruit ripening or leaf senescence compared with the wild type. Next, the expression profile was analyzed, and we found that CmSGR genes were expressed ubiquitously. Moreover, CmSGR1 and CmSGR2 were upregulated, and promoted fruit ripening. CmSGR3 and CmSGR4 were more highly expressed in leaves, cotyledon, and stem compared with CmSGR1 or CmSGR2. Thus, we conclude that CmSGR genes are crucial for fruit ripening and leaf senescence. CmSGR protein structure and function were further clarified to provide a theoretical foundation and valuable information for improved performance of melon.

Determination of carbonyl compounds in water by derivatization-solid-phase microextraction and gas chromatographic analysis

The solid-phase microextraction (SPME) technique was evaluated for the determination of 23 carbonyl compounds in water. The carbonyl compounds in water were derivatized with omicron-(2,3,4,5,6-pentafluorobenzyl)-hydroxylamine hydrochloride (PFBHA), extracted with SPME from liquid or headspace and analyzed by GC with electron capture detection (GC-ECD). The effects of agitation techniques and the addition of salt (NaCl) on extraction, the absorption-time and absorption-concentration profiles were examined. The precision of the SPME technique for the determination of carbonyl compounds was evaluated with spiked bidistilled water, ozonated drinking water, and rain water. The relative standard deviations obtained from different spiked water matrix were similar, and in the range of 5.7-21.1%. The precision can be further improved by using an internal standard. With 4 ml of water sample, the limits of detection for most of the tested carbonyl compounds using liquid or headspace SPME-GC-ECD were similar and in the range of 0.006-0.2 micrograms/l, except for glyoxal and methylglyoxal, which showed low sensitivity when using headspace SPME. In the analysis of an ozonated drinking water sample, the SPME techniques gave comparable results to those of the conventional liquid-liquid extraction method.