ABSTRACT
INTRODUCTION: Radiation proctitis is radiation induced rectal mucositis, occurring as a consequence to radiation therapy of the pelvic organs for various pelvic region malignancies. The management of radiation proctitis is extremely challenging as no recommended guidelines are available and limited number of studies are there in the literature involving the various treatment options. AIM: The aim of the study is the in-depth review of published literature to see the role of various treatment modalities in the management of radiation proctitis. MATERIALS AND METHODS: An integrative review was undertaken within PubMed, MEDLINE, PMC, GOOGLE SEARCH databases and articles published upto February 2015 were reviewed and analysed. A total of 54 studies were included. RESULTS: Literature suggests that non surgical therapies are the first line of treatment and surgery is reserved for advanced or refractory cases. Endoscopic therapies form the mainstay of treatment in managing the patients of radiation proctitis. Argon plasma coagulation and laser therapies are preferred. Radiofrequency ablation, cryoablation and mesenchymal stem cell therapy are the upcoming modalities. Medical therapy can be tried alone or in conjunction to endoscopic therapies. In the resistant or refractory cases, surgery can be looked for in the form of diversion or resection with or without anastamosis. CONCLUSION: Though, a number of options are available, still a lot can be explored in this field to improve the morbidity in the patients and to confirm the superiority of one treatment over other.
ABSTRACT
Several organosulfur compounds are present in the crude oil, and are required to be removed before its processing into transport fuel. For this reason, biodesulfurization of thiophenic compounds has been studied extensively. However, studies on the sulfide compounds are scarce. In this paper, we describe desulfurization of a model sulfidic compound, dibenzyl sulfide (DBS) by an isolated Gordonia sp. IITR100. The reaction was accompanied with the formation of metabolites dibenzyl sulfoxide, dibenzyl sulfone and benzoic acid. Studies with recombinant E. coli revealed that enzyme DszC of this isolate metabolizes DBS into dibenzyl sulfoxide and dibenzyl sulfone, but the reaction downstream to it is mediated by some enzyme other than its DszA. In reactions where DBS and dibenzothiophene (DBT) were present together, both IITR100 and recombinant E. coli exhibited preference for the desulfurization of DBS over DBT. The newly identified capability of IITR100 for desulfurization of both thiophenic and sulfidic compounds suggests its potential use in improved desulfurization of petroleum fractions.
ABSTRACT
Thianthrene (TA) was desulfurized by an isolated strain, Gordonia sp. IITR100. The reaction is accompanied with the formation of TA-sulfoxide, TA-sulfone and 2-phenylsulfanylphenol. The formed 2-phenylsulfanylphenol undergoes further oxidation to o-hydroxyphenyl phenylsulfone that accumulates as an end product. Metabolism of TA to TA-sulfone can also occur by E. coli-DszC i.e. E. coli cells that were harboring the gene coding for the enzyme dibenzothiophene desulfurase C. When presented to E. coli-DszC in a binary combination with dibenzothiophene, TA metabolism was completely inhibited. Metabolism of TA-TA-sulfone by E. coli-DszC, as well as the nature of metabolites formed by IITR100, suggests that the desulfurization pathway for TA is similar to that of the thiophenic compounds. This is first report on the desulfurization of thianthrene, and has implications on biodesulfurization when multiple sulfur compounds are present together.
