Burkitt＇s lymphoma is a highly aggressive non-Hodgkin lymphoma, often presenting in extra-nodal sites. It generally has a poor spontaneous outcome and needs aggressive treatment with systemic and intrathecal chemothe...Burkitt＇s lymphoma is a highly aggressive non-Hodgkin lymphoma, often presenting in extra-nodal sites. It generally has a poor spontaneous outcome and needs aggressive treatment with systemic and intrathecal chemotherapy. Occurrence at the gastric site is rare. We report the case of a 39-year old woman who presented with a prominent ulcerated lesion of the antrum corresponding histologically to a Burkitt＇s lymphoma associated with He/icobacter py/ori （H pylori） infection. Interphase fluorescence in situ hybridization （FISH） demonstrated c-MYC gene rearrangement in tumour cells without BCL2 or BCL6 gene translocations. Ulcer healing and tumour regression with a complete histological response were obtained 8 wk after Hpylori eradication. In spite of this complete remission, taking into account the high risk of recurrence, the patient received systemic and intrathecal chemotherapy. Two years later, the patient remained in complete remission. This is the first report of a gastric Burkitt＇s lymphoma responding to Hpylori eradication. These findings raise the question of the potential role of H pylori in the pathogenesis of some gastric Burkitt＇s lymphomas, and show the importance of searching for and eradicating the bacteria in combination with conventional chemotherapy regimens.展开更多
Stimuli responsive materials have recently been the subject of tremendous research efforts owing to their numerous potential applications. Although there currently exist many different types of ＂smart＂ materials, th...Stimuli responsive materials have recently been the subject of tremendous research efforts owing to their numerous potential applications. Although there currently exist many different types of ＂smart＂ materials, those based on photoresponsive transformations are especially attractive. In this review, we focus on a relatively new class of photochromic molecules based on the photochemistry of chelate organoborates, which form intensely colored, base-stabilized boriranes.Recent efforts to exploit the reactivity of these systems are summarized, and future prospects in materials science discussed.展开更多
Desymmetrization of prochiral 3-substituted glutaronitriles offers a new approach to access （S）-Pregabalin and （R）-Baclofen. A number of nitrilases from diverse sources were screened with 3-isobutylglutaronitriles...Desymmetrization of prochiral 3-substituted glutaronitriles offers a new approach to access （S）-Pregabalin and （R）-Baclofen. A number of nitrilases from diverse sources were screened with 3-isobutylglutaronitriles （1a） or 3-（4＇-chlorophenyl）glutaronitriles （1b） as the substrate. Some nitrilases were found to catalyze the desymmetric hydrolysis of la and lb to form optically active 3-（cyanomethyl）-5-methylhexanoic acid （2a） and 3-（4＇-chlorophenyl）-4-cyanobutanoic acid （2b） with high enantiomeric excesse （ee）, respectively. This cannot be achieved using traditional chemical hydrolysis. Among them, AtNIT3 generated （R）-2b whereas BjNIT6402 and HsN1T produced the opposite （S）-enantiomer with high conversions and ee values. Not only the nitrilases showed different activities and stereoselectivities toward these 3-substituted glutaronitriles, the 3-substitueut of the substrates also exerted great effect on the enzyme activity and stereoselectivity. （S）-2a and （S）-2b were prepared with high yields and ee values using BjNIT6402 and HsNIT as the biocatalysts, respectively. A straightforward Curtius rearrangement of （S）-2a and （S）-2b, followed by the acidic hydrolysis, afforded （S）-Pregabalin and （R）-Baclofen. This offers a new platform methodology for the synthesis of optically active β-substituted T-amino acids of pharmaceutical importance.展开更多
文摘Burkitt＇s lymphoma is a highly aggressive non-Hodgkin lymphoma, often presenting in extra-nodal sites. It generally has a poor spontaneous outcome and needs aggressive treatment with systemic and intrathecal chemotherapy. Occurrence at the gastric site is rare. We report the case of a 39-year old woman who presented with a prominent ulcerated lesion of the antrum corresponding histologically to a Burkitt＇s lymphoma associated with He/icobacter py/ori （H pylori） infection. Interphase fluorescence in situ hybridization （FISH） demonstrated c-MYC gene rearrangement in tumour cells without BCL2 or BCL6 gene translocations. Ulcer healing and tumour regression with a complete histological response were obtained 8 wk after Hpylori eradication. In spite of this complete remission, taking into account the high risk of recurrence, the patient received systemic and intrathecal chemotherapy. Two years later, the patient remained in complete remission. This is the first report of a gastric Burkitt＇s lymphoma responding to Hpylori eradication. These findings raise the question of the potential role of H pylori in the pathogenesis of some gastric Burkitt＇s lymphomas, and show the importance of searching for and eradicating the bacteria in combination with conventional chemotherapy regimens.
基金financially supported by the Natural Science and Engineering Research Council of Canada (RGPIN:1193993-2013)the National Natural Science Foundation of China (21501017)
文摘Stimuli responsive materials have recently been the subject of tremendous research efforts owing to their numerous potential applications. Although there currently exist many different types of ＂smart＂ materials, those based on photoresponsive transformations are especially attractive. In this review, we focus on a relatively new class of photochromic molecules based on the photochemistry of chelate organoborates, which form intensely colored, base-stabilized boriranes.Recent efforts to exploit the reactivity of these systems are summarized, and future prospects in materials science discussed.
基金financially supported by the Chinese Academy of Sciences (KSZD-EW-Z-015)the CAS Agenda to Provide S&T Support and Services for the National Strategic Emerging Industries
文摘Desymmetrization of prochiral 3-substituted glutaronitriles offers a new approach to access （S）-Pregabalin and （R）-Baclofen. A number of nitrilases from diverse sources were screened with 3-isobutylglutaronitriles （1a） or 3-（4＇-chlorophenyl）glutaronitriles （1b） as the substrate. Some nitrilases were found to catalyze the desymmetric hydrolysis of la and lb to form optically active 3-（cyanomethyl）-5-methylhexanoic acid （2a） and 3-（4＇-chlorophenyl）-4-cyanobutanoic acid （2b） with high enantiomeric excesse （ee）, respectively. This cannot be achieved using traditional chemical hydrolysis. Among them, AtNIT3 generated （R）-2b whereas BjNIT6402 and HsN1T produced the opposite （S）-enantiomer with high conversions and ee values. Not only the nitrilases showed different activities and stereoselectivities toward these 3-substituted glutaronitriles, the 3-substitueut of the substrates also exerted great effect on the enzyme activity and stereoselectivity. （S）-2a and （S）-2b were prepared with high yields and ee values using BjNIT6402 and HsNIT as the biocatalysts, respectively. A straightforward Curtius rearrangement of （S）-2a and （S）-2b, followed by the acidic hydrolysis, afforded （S）-Pregabalin and （R）-Baclofen. This offers a new platform methodology for the synthesis of optically active β-substituted T-amino acids of pharmaceutical importance.
