ALBERT

Description: Background: Myxoid liposarcoma is the most common soft-tissue sarcoma that metastasizes to the peritoneal cavity. Recently, an advanced intensity-modulated radiotherapy, known as helical tomotherapy, has been introduced to improve target coverage, while reducing normal tissue radiation. Here, we report a case of myxoid liposarcoma with multiple peritoneal seeding that was chemotherapy-refractory, but was successfully salvaged by helical tomotherapy-based intraperitoneal radiotherapy.Case presentationA 71-year-old East-Asian male was initially diagnosed with myxoid liposarcoma in his left thigh by excision. Six years later, the patient underwent a left pneumonectomy for metastatic myxoid liposarcoma in the left lung. Since then, the patient was treated with two segmental resections, and multiple lines of chemotherapy, for repeated recurrences in the peritoneal cavity. The patient underwent intraperitoneal radiotherapy followed by tumor boost radiotherapy, as salvage treatment for chemotherapy-resistant metastatic peritoneal myxoid liposarcoma. The prescribed dose was 24 Gy delivered in 15 fractions of 1.6 Gy over 3 weeks, followed by a 16 Gy boost dose administered in eight fractions of 2 Gy, to multifocal peritoneal lesions. A positron emission tomography scan obtained 8 weeks after completion of radiotherapy, showed a complete metabolic response of metastatic peritoneal lesions. Radiotherapy was well tolerated, without any side effects. In a computed tomography scan obtained 20 weeks after completion of radiotherapy, most of the peritoneal metastatic lesions had disappeared, except for two small residual nodules. Conclusion: This case suggests that low fraction-sized intraperitoneal radiotherapy (1.6 Gy administered once daily), followed by a focal boost using helical tomotherapy, is a feasible treatment without side effects. It produced an excellent tumor response, and durable intraperitoneal control for metastatic peritoneal myxoid liposarcoma.

Description: Background Two stages of genome activation have been identified in the mouse embryo. Specifically, minor transcriptional activation is evident at the one-cell stage and a second major episode of activation occurs at the two-cell stage. Nuclear translocation of RNA polymerase II and phosphorylation of the C-terminal domain (CTD) of the largest enzyme subunit are major determinants of embryonic genome activation. P-TEFb, the Pol II CTD kinase, regulates transcriptional elongation via phosphorylation of the serine 2 residues of the CTD. Results Here, we show that the CDK9 and cyclin T1 subunits of P-TEFb are present in mouse oocytes and preimplantation embryos. Both proteins translocate to pronuclei at the late one-cell stage and are predominantly localized in nuclei at the two-cell stage. We additionally examine the effects of the CDK9-specific inhibitor, flavopiridol, on mouse preimplantation development. Our data show that treatment with the drug results in mislocalization of CDK9, cyclin T1, and phosphorylated Pol II, as well as developmental arrest at the two-cell stage. Conclusions A change in CDK9 localization from the cytoplasm to the pronucleus occurs at the time of minor embryonic genome activation, and CDK9 accumulation at the two-cell stage is evident, concomitant with major transcriptional activation of the embryonic genome. Moreover, CDK9 inhibition triggers a developmental block at the two-cell stage. Our findings clearly indicate that CDK9 is essential for embryonic genome activation in the mouse.

Description: Background Xanthomonas oryzae pv. oryzae, the causal agent of bacterial blight disease, is a serious pathogen of rice. Here we describe a fluorescent marker system to study virulence and pathogenicity of X. oryzae pv. oryzae. Results A fluorescent X. oryzae pv. oryzae Philippine race 6 strain expressing green fluorescent protein (GFP) (PXO99GFP) was generated using the gfp gene under the control of the neomycin promoter in the vector, pPneo-gfp. The PXO99GFPstrain displayed identical virulence and avirulence properties as the wild type control strain, PXO99. Using fluorescent microscopy, bacterial multiplication and colonization were directly observed in rice xylem vessels. Accurate and rapid determination of bacterial growth was assessed using fluoremetry and an Enzyme-Linked ImmunoSorbant Assay (ELISA). Conclusion Our results indicate that the fluorescent marker system is useful for assessing bacterial infection and monitoring bacterial multiplication in planta.