Targeting the spliceosome in chronic lymphocytic leukemia with the macrolides FD-895 and pladienolide-B

RNA splicing plays a fundamental role in human biology. Its relevance in cancer is rapidly emerging as demonstrated by spliceosome mutations that determine the prognosis of patients with hematologic malignancies. We report studies using FD-895 and pladienolide-B in primary leukemia cells derived from patients with chronic lymphocytic leukemia and leukemia-lymphoma cell lines. We found that FD-895 and pladienolide-B induce an early pattern of mRNA intron retention – spliceosome modulation. This process was associated with apoptosis preferentially in cancer cells as compared to normal lymphocytes. The pro-apoptotic activity of these compounds was observed regardless of poor prognostic factors such as Del(17p), TP53 or SF3B1 mutations and was able to overcome the protective effect of culture conditions that resemble the tumor microenvironment. In addition, the activity of these compounds was observed not only in vitro but also in vivo using the A20 lymphoma murine model. Overall, these findings give evidence for the first time that spliceosome modulation is a valid target in chronic lymphocytic leukemia and provide an additional rationale for the development of spliceosome modulators for cancer therapy.     

Sertoli Leydig cell tumor with heterologous gastrointestinal epithelium: a case report

Sertoli Leydig cell tumour (SLCT) of the ovary with the presence of heterologous elements is very unusual. A case of SLCT with virilizing symptoms and androgenic endocrinological profile is presented. The tumor showed presence of heterologous element in the form of mucinous epithelium of the gastrointestinal type.     

An Ixodes scapularis protein required for survival of Anaplasma phagocytophilum in tick salivary glands

Anaplasma phagocytophilum is the agent of human anaplasmosis, the second most common tick-borne illness in the United States. This pathogen, which is closely related to obligate intracellular organisms in the genera Rickettsia, Ehrlichia, and Anaplasma, persists in ticks and mammalian hosts; however, the mechanisms for survival in the arthropod are not known. We now show that A. phagocytophilum induces expression of the Ixodes scapularis salp16 gene in the arthropod salivary glands during vector engorgement. RNA interference-mediated silencing of salp16 gene expression interfered with the survival of A. phagocytophilum that entered ticks fed on A. phagocytophilum-infected mice. A. phagocytophilum migrated normally from A. phagocytophilum-infected mice to the gut of engorging salp16-deficient ticks, but up to 90% of the bacteria that entered the ticks were not able to successfully infect I. scapularis salivary glands. These data demonstrate the specific requirement of a pathogen for a tick salivary protein to persist within the arthropod and provide a paradigm for understanding how Rickettsia-like pathogens are maintained within vectors.     

Acute,sub-acute and general pharmacological evaluation of 5-(3,4-methylenedioxyphenyl)-4-ethyl-2E,4E-pentadienoic acid piperidide (SK-20): A novel drug bioavailability enhancer

An efflux pump inhibitor, SK-20 (5-(3,4-methylenedioxyphenyle)-4 ethyl-2E,4E-pentadienoic acid piperidide), was assessed for its toxicity at three different pharmacological profiles: acute, sub-acute and general pharmacology with pharmacokinetics. In acute study, the SK-20 was found safe up to a dose of 2000 mg/kg (b.wt.); and at sub-acute, dosages of 50 and 100 mg/kg (b.wt.) were found to be safe. However, dosages of 200 mg or above per kg (b.wt.) showed some morphological alterations in cellular architecture of both liver and kidneys in both sexes, viz., mild vascular congestion along with sporadic hemorrhages and infiltration into renal and hepatic parenchyma by mononucleate cell. General pharmacological studies did not result into any alterations in analgesic, convulsions, rectal temperatures and in the rhythm or the rate of the intestinal motility or the secretion of the bile. While the respiratory and the cardiac rate remained normal, the only parameter to show was the blood pressure, which at all the doses tested, showed a tendency toward reduction. Characteristically, the SK-20 at all doses influenced pentobarbital-induced hypnosis positively and negatively to spontaneous motor activity in a dose dependent manner. Pharmacokinetics of SK-20 revealed it to have retention time at 10.2 min and half life 2.47 h.     

Diagnosis and Management of Atypical Hemolytic Uremic Syndrome In Children: Single Centre Experience

Atypical hemolytic uremic syndrome (aHUS) although rare is the commonest cause of acute renal failure (ARF) in children and has poor prognosis. We present single centre experience of aHUS. Thirty six children (29 males, 7 females) with mean age, 7.9 years presented with ARF, 2 children also had tonic–clonic type convulsions. Their hematology examination revealed hemolytic anemia with s. creatinine (SCr), 5.54 mg/dl. Acute HUS was observed in 75 %, acute on chronic HUS in 19.4 % and patchy cortical necrosis (PCN) in 5.6 % biopsies. Mean 5.4 plasma exchanges (PE) were carried out. Supportive management of anti-hypertensives and prednisone was also given. Recovery end points were establishment of urine output, improvement of SCr and hematological profile. Hematology and renal function profile improved variably in all children, 5.6 % died, relapse was observed in 80.5 % over mean 70 days; 13.9 % children are doing well over mean follow-up of 268.8 days. Thus poor prognosis was observed in 86.1 % children. Children with acute on chronic HUS and PCN did not recover. Six children who recovered had acute HUS. aHUS in Indian children occurs at an older age of around 8 years and chronic/irreversible changes on histopathology examination are harbingers of poor prognosis. PE is life-saving however further research for developing strategies to improve long-term survival is needed.     

Outer membrane protein A (OmpA) from Shigella flexneri 2a: A promising subunit vaccine candidate

Shigellosis is the leading cause of childhood mortality and morbidity. Despite many years of extensive research a practical vaccine is not yet available against the disease. Recent studies illustrate that bacterial outer membrane proteins are budding target as vaccine antigen. Outer membrane proteins A (OmpA) are among the most immunodominant antigens in the outer membrane of gram negative bacteria and possess many characteristics desired of a vaccine candidate. We observe that OmpA of Shigella flexneri 2a is crossreactive and common antigen among Shigella spp. and the epitope is widely exposed on the cell surface as well as capable of evoking protective immunity in mice. The protective immunity involves participation of both the humoral and cellular immune responses, since OmpA boosts rapid induction of IgG and IgA in both the systemic and mucosal compartments and also activates Th1 cells. The immunopotentiating activity of OmpA is mediated by its ability to bind and stimulate macrophages and up-regulate the surface expression of MHCII, CD80 and CD40, leading to activation of CD4⁺ T cells to secrete cytokines and express chemokine receptor and IL-12Rβ2, thereby orchestrating the bridge between innate and adaptive immune responses. This ability is dependent on Toll-like receptor 2 (TLR2), as demonstrated by lack of response by TLR2 knockdown macrophages to OmpA. Hence this property of OmpA to link innate and adaptive immunity via TLR2 offers a novel vista to develop vaccine against shigellosis.     

Reversible complete atrioventricular block after percutaneous ASD device closure in a child <15 kg

Transcatheter device closure of atrial septal defect (ASD) in small children less than 15 kg may be associated with increased complications. Complete atrioventricular heart block (CHB) is a rare complication of ASD device closure in such a setting. We report the case of a 2-year-old girl, less than 15 kg, who underwent device closure of ASD with Amplatzer Septal Occluder and subsequently developed CHB 12 h after the procedure which resolved completely with steroid treatment on fifth day. Case report of a similar kind is rarely reported in the literature. Despite adequate postero-inferior margin CHB may still occur in small children as in our case.