RAKESH KUMAR - Academia.edu (original) (raw)
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Papers by RAKESH KUMAR
Journal of clinical neonatology, 2012
Proteus syndrome is a rare hamartomatous disorder affecting multiple tissues and manifesting itse... more Proteus syndrome is a rare hamartomatous disorder affecting multiple tissues and manifesting itself in a variety of ways. The understanding of the complete spectrum of clinical features, the natural clinical course of the disease and the proper management of such a rare but highly variable syndrome depend heavily on experiences gathered by previously reported cases. We present an unusually severely affected and rapidly progressive case of proteus syndrome in a neonate who presented with craniofacial hemihypertrophy, subcutaneous masses, capillary hemangioma, varicose veins, epidermal nevi and macrodactyly. The cranial ultrasonogram revealed unilateral hydrocephalus with partial obstruction of the foramen of monro.
Frontiers in oncology, 2012
In order to survive, cells have evolved highly effective repair mechanisms to deal with the poten... more In order to survive, cells have evolved highly effective repair mechanisms to deal with the potentially lethal DNA damage produced by exposure to endogenous as well as exogenous agents. Ionizing radiation exposure induces highly lethal DNA damage, especially DNA double-strand breaks (DSBs), that is sensed by the cellular machinery and then subsequently repaired by either of two different DSB repair mechanisms: (1) nonhomologous end joining, which re-ligates the broken ends of the DNA and (2) homologous recombination, that employs an undamaged identical DNA sequence as a template, to maintain the fidelity of DNA repair. Repair of DSBs must occur within the natural context of the cellular DNA which, along with specific proteins, is organized to form chromatin, the overall structure of which can impede DNA damage site access by repair proteins. The chromatin complex is a dynamic structure and is known to change as required for ongoing cellular processes such as gene transcription or DNA replication. Similarly, during the process of DNA damage sensing and repair, chromatin needs to undergo several changes in order to facilitate accessibility of the repair machinery. Cells utilize several factors to modify the chromatin in order to locally open up the structure to reveal the underlying DNA sequence but post-translational modification of the histone components is one of the primary mechanisms. In this review, we will summarize chromatin modifications by the respective chromatin modifying factors that occur during the DNA damage response.
The Journal of organic chemistry, Jan 5, 2012
Metalation-electrophilic fluorination of TMS- and TIPS-protected 1,3-benzothiazol-2-yl (BT) propa... more Metalation-electrophilic fluorination of TMS- and TIPS-protected 1,3-benzothiazol-2-yl (BT) propargyl sulfones gave corresponding BT fluoropropargyl sulfones, Julia-Kocienski reagents for the synthesis of fluoro enynes. Both reagents reacted with aldehydes under mild DBU- or LHMDS-mediated conditions, giving high yields of conjugated fluoro enynes with E-stereoselectivity. In comparison to DBU-mediated reactions, stereoselectivity was higher in low-temperature LHMDS-mediated reactions. Two ketones were shown to react as well, using LHMDS as base. In situ removal of the TMS group gave terminal conjugated 2-fluoro 1,3-enynes. Synthetic utility of the fluoro enynes was demonstrated by conversion to internal alkynes and to stereoisomeric fluoro dienes via Sonogashira and Heck couplings.
Journal of clinical neonatology, 2012
Proteus syndrome is a rare hamartomatous disorder affecting multiple tissues and manifesting itse... more Proteus syndrome is a rare hamartomatous disorder affecting multiple tissues and manifesting itself in a variety of ways. The understanding of the complete spectrum of clinical features, the natural clinical course of the disease and the proper management of such a rare but highly variable syndrome depend heavily on experiences gathered by previously reported cases. We present an unusually severely affected and rapidly progressive case of proteus syndrome in a neonate who presented with craniofacial hemihypertrophy, subcutaneous masses, capillary hemangioma, varicose veins, epidermal nevi and macrodactyly. The cranial ultrasonogram revealed unilateral hydrocephalus with partial obstruction of the foramen of monro.
Frontiers in oncology, 2012
In order to survive, cells have evolved highly effective repair mechanisms to deal with the poten... more In order to survive, cells have evolved highly effective repair mechanisms to deal with the potentially lethal DNA damage produced by exposure to endogenous as well as exogenous agents. Ionizing radiation exposure induces highly lethal DNA damage, especially DNA double-strand breaks (DSBs), that is sensed by the cellular machinery and then subsequently repaired by either of two different DSB repair mechanisms: (1) nonhomologous end joining, which re-ligates the broken ends of the DNA and (2) homologous recombination, that employs an undamaged identical DNA sequence as a template, to maintain the fidelity of DNA repair. Repair of DSBs must occur within the natural context of the cellular DNA which, along with specific proteins, is organized to form chromatin, the overall structure of which can impede DNA damage site access by repair proteins. The chromatin complex is a dynamic structure and is known to change as required for ongoing cellular processes such as gene transcription or DNA replication. Similarly, during the process of DNA damage sensing and repair, chromatin needs to undergo several changes in order to facilitate accessibility of the repair machinery. Cells utilize several factors to modify the chromatin in order to locally open up the structure to reveal the underlying DNA sequence but post-translational modification of the histone components is one of the primary mechanisms. In this review, we will summarize chromatin modifications by the respective chromatin modifying factors that occur during the DNA damage response.
The Journal of organic chemistry, Jan 5, 2012
Metalation-electrophilic fluorination of TMS- and TIPS-protected 1,3-benzothiazol-2-yl (BT) propa... more Metalation-electrophilic fluorination of TMS- and TIPS-protected 1,3-benzothiazol-2-yl (BT) propargyl sulfones gave corresponding BT fluoropropargyl sulfones, Julia-Kocienski reagents for the synthesis of fluoro enynes. Both reagents reacted with aldehydes under mild DBU- or LHMDS-mediated conditions, giving high yields of conjugated fluoro enynes with E-stereoselectivity. In comparison to DBU-mediated reactions, stereoselectivity was higher in low-temperature LHMDS-mediated reactions. Two ketones were shown to react as well, using LHMDS as base. In situ removal of the TMS group gave terminal conjugated 2-fluoro 1,3-enynes. Synthetic utility of the fluoro enynes was demonstrated by conversion to internal alkynes and to stereoisomeric fluoro dienes via Sonogashira and Heck couplings.