Congenital Pulmonary Lymphangiectasia Masked by Postoperative Pulmonary Venous Obstruction in an Infant with Total Anomalous Pulmonary Venous Connection.

Congenital pulmonary lymphangiectasia (CPL) is associated with fetal pulmonary venous obstructive physiology. The precise morbidity of CPL is unknown as CPL is generally fatal in neonates. Here, we report an infant with secondary CPL in total anomalous pulmonary venous connection (TAPVC). He developed severe pulmonary hypertension (PH) after corrective surgery for TAPVC. However, cardiac catheterization showed mild left pulmonary venous obstruction (PVO), which was deemed unnecessary for re-intervention. He died at 11 months-old due to an exacerbation of PH. Autopsy revealed medial hypertrophy of the pulmonary arteries, mild left PVO, and marked dilatation and proliferation of the pulmonary lymphatics which might have been involved in the PH, although CPL was not conclusively identified based on the previous biopsy findings. We should be aware of the possibility of CPL in addition to postoperative PVO when encountering patients with fetal pulmonary venous obstructive physiology. Furthermore, a cautious approach to the interpretation of lung biopsy results is warranted.

Low temperature modulates natural peel degreening in lemon fruit independently of endogenous ethylene.

Peel degreening is an important aspect of fruit ripening in many citrus fruit, and previous studies have shown that it can be advanced by ethylene treatment or by low-temperature storage. However, the important regulators and pathways involved in natural peel degreening remain largely unknown. To determine how natural peel degreening is regulated in lemon fruit (Citrus limon), we studied transcriptome and physiochemical changes in the flavedo in response to ethylene treatment and low temperatures. Treatment with ethylene induced rapid peel degreening, which was strongly inhibited by the ethylene antagonist, 1-methylcyclopropene (1-MCP). Compared with 25 ºC, moderately low storage temperatures of 5-20 °C also triggered peel degreening. Surprisingly, repeated 1-MCP treatments failed to inhibit the peel degreening induced by low temperature. Transcriptome analysis revealed that low temperature and ethylene independently regulated genes associated with chlorophyll degradation, carotenoid metabolism, photosystem proteins, phytohormone biosynthesis and signalling, and transcription factors. Peel degreening of fruit on trees occurred in association with drops in ambient temperature, and it coincided with the differential expression of low temperature-regulated genes. In contrast, genes that were uniquely regulated by ethylene showed no significant expression changes during on-tree peel degreening. Based on these findings, we hypothesize that low temperature plays a prominent role in regulating natural peel degreening independently of ethylene in citrus fruit.