Transcriptomic and Metabolic Analyses Reveal the Mechanism of Ethylene Production in Stony Hard Peach Fruit during Cold Storage

Stony hard (SH) peach (Prunus persica L. Batsch) fruit does not release ethylene and has very firm and crisp flesh at ripening, both on- and off-tree. Long-term cold storage can induce ethylene production and a serious risk of chilling injury in SH peach fruit; however, the regulatory mechanism underlying ethylene production in stony hard peach is relatively unclear. In this study, we analyzed the phytohormone levels, fruit firmness, transcriptome, and lipidome changes in SH peach ‘Zhongtao 9’ (CP9) during cold storage (4 °C). The expression level of the ethylene biosynthesis gene PpACS1 and the content of ethylene in SH peach fruit were found to be upregulated during cold storage. A peak in ABA release was observed before the release of ethylene and the genes involved in ABA biosynthesis and degradation, such as zeaxanthin epoxidase (ZEP) and 8’-hydroxylase (CYP707A) genes, were specifically induced in response to low temperatures. Fruit firmness decreased fairly slowly during the first 20 d of refrigeration, followed by a sharp decline. Furthermore, the expression level of genes encoding cell wall metabolic enzymes, such as polygalacturonase, pectin methylesterase, expansin, galactosidase, and β-galactosidase, were upregulated only upon refrigeration, as correlated with the decrease in fruit firmness. Lipids belonging to 23 sub-classes underwent differential rearrangement during cold storage, especially ceramide (Cer), monoglycosylceramide (CerG1), phosphatidic acid (PA), and diacyglyceride (DG), which may eventually lead to ethylene production. Exogenous PC treatment provoked a higher rate of ethylene production. We suspected that the abnormal metabolism of ABA and cell membrane lipids promotes the production of ethylene under low temperature conditions, causing the fruit to soften. In addition, ERF transcription factors also play an important role in regulating lipid, hormone, and cell wall metabolism during long-term cold storage. Overall, the results of this study give us a deeper understanding of the molecular mechanism of ethylene biosynthesis during the postharvest storage of SH peach fruit under low-temperature conditions.

Large Right Atrial Myxoma Masquerading as Malignancy

A 57-year-old female presented to emergency with features of right heart failure. On evaluation, she was found to have a large mass occupying right atrium (RA) completely and protruding into right ventricle through tricuspid valve. Intraoperatively, mass was seen arising from RA free wall with stony hard consistency. Histopathology revealed it to be myxoma. We present this case for the rare presentation of myxoma masquerading as malignancy.

An Unusual Riddle of Thyroid Swelling; Hodgkin’s Lymphoma Masquerading as Riedel’s Thyroiditis

Introduction: Thyroid swellings are one of the most common encountered endocrinological presentations however the prevalence of malignancy is about 4-6.5%. Hodgkin lymphomas usually present as neck swelling in form lymphadenopathy and Hodgkin disease affecting the thyroid gland is extremely rare (1-2.5% of all lymphomas). It usually occurs in middle age and has predilection for female gender. It can pose a diagnostic challenge with the histology of sclerosing fibrosis mimicking Riedel’s thyroiditis; another rare cause of stony hard goitre. Case History: A 39yr old female presented with rapidly enlarging painful thyroid mass. She complained of mild dysphagia but denied to have dyspnoea, dysphonia wheeze or stridor. There was no history of weight loss, B symptoms or any significant past illness. Clinically and biochemically she was euthyroid with normal TSH 0.73mU/l(0.35-3.50), Free thyroxine 13pmol/L (8-21), Free T3 3.9pmol/L (3.8-6.0). Blood count showed mild neutrophilia 8.21 (2-7x109/L). IGG subclasses 1-4 were all with normal limits. Initial Ultrasonography demonstrated 4.6 X 3.6cm U3 thyroid nodule extending retrosternally. FNA x2 was THY. Core biopsy demonstrated dense core of fibrous tissue with crushed aggregates of mature lymphoid cells and mixed neutrophils and histiocytes in keeping with fibro inflammatory process suggestive of Riedel’s thyroiditis. Patient was initiated on Prednisolone 100mg OD by the ENT surgeons after MDT discussion and patient had some symptomatic improvement in pain but no discernible reduction in size. Due to side effects from steroids she was referred to endocrinology department. Tamoxifen 20mg BD was started for symptom management. CTNCAP was organised to rule out lymphoproliferative disorder which was negative barring the known thyroid mass. She had no response to Tamoxifen either hence she underwent surgical resection. Surgical resection deemed very difficult due to mass infiltrating the strap muscles and neck vasculature hence wedge resection of the isthmus was done. Histology now revealed bands of dense fibrous tissue with admixed large lymphoid cells showing enlarged, red nucleoli. Immunohistochemistry of the large atypical lymphoid cells expressed CD30, CD15, MUM1, PAX5, CD20, CD79a and BCL6 and diagnosis was revised to Classic Hodgkin lymphoma, nodular sclerosis subtype. She was then referred to haematologist who initiated ABVD chemotherapy and her latest FDG PET scan shows complete metabolic response with significant reduction in the thyroid mass to 17mm X16 mm. Conclusion: Primary thyroid lymphoma can mimic Riedel’s and other forms of fibrosing thyroiditis. Most lymphomas arise from Hashimoto’s thyroiditis. Stony hard neck swellings are difficult to FNA and even core biopsy may not reveal the diagnosis, hence surgical resection and histological diagnosis should be sought earlier as most lymphomas respond well to chemotherapy.

Pseudoparalysis of Marginal Mandibular Nerve Branch by Big Submandibular Gland Sailolith: A Case Report

Sailolithiasis is the second most common etiology of salivary gland after sialadenitis. Present case of 29 years old male patient with giant submandibular sailolith with stony hard feel below the left angle of the mandible. X ray and CECT neck used for confirmation. Because of big stone incidental finding of pressure paresis of marginal mandibular nerve was noticed. Even patient unaware of that. En-block Submandibular salivary gland excision was done by trans-cervical approach with complete recovery of the nerve within 3-4 post-operative weeks.

Juvenile variant ossifying fibroma of sinonasal region

Juvenile variant ossifying fibroma of sinonasal region is an extremely rare benign fibro-osseous lesion which is locally aggressive. A 21-year-old male presented with significant proptosis of right eye with stony-hard lump in the middle upper aspect of the right orbit and base of the nose. CT scan of head revealed a non-enhancing expansile lesion in right ethmoidal cells consistent with chronic ethmoidal mucocele. However Magnetic Resonance Imaging of brain revealed enhancing lesion in right ethmoid and frontal sinus extending up to anterior cranial fossa. He underwent right frontal craniotomy with surgical excision of tumor wherein cystic brown tumor of frontal and ethmoidal sinus was found. The procedure was supplemented with endoscopic transnasal approach. Histopathology report suggested an ossifying fibroma. This case highlights the importance of clinical, imaging and histopathological features of ossifying fibroma occurring in the sinonasal tract for better diagnosis and treatment through a multidisciplinary approach.

A RARE AND INTERESTING PRESENTATION OF LUNG TUMOUR

A 72 year old male presented with a chief complaint of groin swelling and was clinically diagnosed as direct inguinal hernia and was planned for hernioplasty. Patient had no respiratory symptoms like cough or haemoptysis. Incidentally it was found that patient was having mass lesion on the left side in chest x ray and was referred to CTVS department. The patient however had no complaints pertaining to the mass. He underwent CECT and was found to have ?peripheral bronchogenic tumour in left posterior mediastinum. Later left posterolateral thoracotomy was done and intra operatively mass was found originating from left lower lobe of lung and left lower lobectomy was done. Mass was around 10x15x10 cms, stony hard in consistency within the left lower lobe. The entire specimen was sent for HPE. Post operatively the patient was stable and regularly followed up. HPE of the mass was pulmonary hamartoma.