Mitochondrial Sirtuin Network Reveals Dynamic SIRT3-Dependent Deacetylation in Response to Membrane Depolarization.

Mitochondrial sirtuins, SIRT3-5, are NAD+-dependent deacylases and ADP-ribosyltransferases that are critical for stress responses. However, a comprehensive understanding of sirtuin targets, regulation of sirtuin activity, and the relationships between sirtuins remains a key challenge in mitochondrial physiology. Here, we employ systematic interaction proteomics to elucidate the mitochondrial sirtuin protein interaction landscape. This work reveals sirtuin interactions with numerous functional modules within mitochondria, identifies candidate sirtuin substrates, and uncovers a fundamental role for sequestration of SIRT3 by ATP synthase in mitochondrial homeostasis. In healthy mitochondria, a pool of SIRT3 binds ATP synthase, but upon matrix pH reduction with concomitant loss of mitochondrial membrane potential, SIRT3 dissociates. This release correlates with rapid deacetylation of matrix proteins, and SIRT3 is required for recovery of membrane potential. In vitro reconstitution experiments, as well as analysis of CRISPR/Cas9-engineered cells, indicate that pH-dependent SIRT3 release requires H135 in the ATP5O subunit of ATP synthase. Our SIRT3-5 interaction network provides a framework for discovering novel biological functions regulated by mitochondrial sirtuins.

Management of colorectal cancer liver metastasis in a patient with immune thrombocytopaenia.

Immune thrombocytopaenia (ITP) was referred to previously as idiopathic thrombocytopaenic purpura and is usually of autoimmune or viral aetiology. Colorectal cancer liver metastasis with concomitant ITP is rare and only three cases have been reported in the English literature. Adverse effects of adjuvant chemotherapy may aggravate ITP. The sequencing of chemotherapy, operation for the primary and liver metastasis, and a decision on splenectomy is important. We present our experience in the management of a 52-year-old man who, having undergone anterior resection one year earlier for carcinoma of the rectum, presented with liver metastasis and ITP. He underwent splenectomy with hepatectomy prior to chemotherapy.

Benign biliary papillomatosis in a patient with a choledochal cyst presenting as haemobilia: a case report.

Biliary papillomatosis is a rare condition usually detected on imaging or postoperative histopathology. It may be asymptomatic or present with features of cholangitis. We report the management of a patient presenting with haemobilia.

Jejunal access loop cholangiogram and intervention using image guided access.

Jejunal access loop is fashioned in patients who undergo Roux en Y hepaticojejunostomy and biliary intervention is anticipated on follow up. Post-operative study of the biliary tree through the access loop is usually done under fluoroscopic guidance. We present a series of 20 access loop cholangiograms performed in our institution between August 2004 and November 2008. We aimed to evaluate the safety and efficacy of the procedure and to highlight the role of CT guidance in procuring access. Access loop was accessed using CT (n = 13), ultrasound (n = 3) or fluoroscopic guidance (n = 4). Fluoroscopy was used for performing cholangiograms and interventions. Twelve studies had balloon plasty of the stricture at anastomotic site or high up in the hepatic ducts. Seven studies showed normal cholangiogram. Plasty was unsuccessful in one study. Technical success in accessing the jejunal access loop was 100%; in cannulation of anastomotic site and balloon plasty it was 95%. One case required two attempts. Procedure-related complications were not seen. All patients who underwent balloon plasty of the stricture were doing well for variable lengths of time. Access loop cholangiogram and interventions are safe and effective. CT guidance in locating/procuring the access loop is a good technique.

Malignant phyllodes tumour with intraductal and invasive carcinoma and lymph node metastasis.

Phyllodes tumours constitute 2-3 percent of fibroepithelial breast tumours, with a 1-2 percent rate of malignancy. Metastasis is usually haematogeneous, and axillary lymph node dissection is not routinely performed. Carcinoma in a phyllodes tumour is distinctly uncommon, but has been known to occur in benign phyllodes tumours. We describe a 51-year-old woman with a malignant phyllodes tumour with foci of intraductal carcinoma within the tumour and adjacent breast tissue. Though the carcinoma was found to be invasive based on the presence of carcinomatous lymph node metastasis, extensive sampling did not yield an invasive component within the breast, probably because of the marked stromal overgrowth of the phyllodes. A malignant phyllodes tumour with foci of intraductal carcinoma and axillary lymph node metastases was diagnosed rather than carcinosarcoma. Chemotherapy and irradiation were included in the postoperative management. Coexistence of phyllodes tumour and carcinoma is rare, and extensive sampling may be necessary to find the foci of carcinoma within an extensive and obviously malignant stromal overgrowth. There is little consensus on the treatment and prognosis in these cases, and it is recommended that treatment be tailored to individual patients, based on the presence of invasion, lymph node metastasis and/or distant metastasis.

Endoluminal formalin application for haemorrhagic radiation proctitis.

BACKGROUND: Radiation proctitis is a common complication following radiation therapy for pelvic malignancies. This is associated with significant morbidity which adversely affects the quality of life. Local application of formalin has been used effectively in the treatment of radiation proctitis. METHODOLOGY: Thirty patients with haemorrhagic radiation proctitis who underwent endoluminal application of 4% formalin between January 1998 to October 2002 were followed up prospectively to assess the efficacy of the treatment. RESULTS: The follow up ranged from 5 to 36 months (mean 18.1 months). Nineteen (63.3%) patients had complete response to formalin application while 7 (23.3%) patients had partial response. There were 4 (13.3%) failures. No procedure related complication was observed. CONCLUSION: Local application of formalin is a simple, safe, inexpensive and fairly effective outpatient treatment modality for chronic radiation proctitis.

Cavernous haemangioma of the rectum: an uncommon cause of rectal bleeding.

Cavernous haemangioma of the rectum is an uncommon cause of rectal bleeding. Initial diagnosis is often elusive because of lack of awareness. For accurate diagnosis, investigations such as endoscopy, plain X-ray of the abdomen, barium enema and selective angiography of the inferior mesenteric artery are required. Complete surgical excision of the haemangioma and colo-anal sleeve anastomosis is the most favoured operative procedure to eradicate the disease. We report a case of cavernous haemangioma of the rectum and discuss its salient clinical features, investigations and management.