New inhibitors for the BPTF bromodomain enabled by structural biology and biophysical assay development.

Bromodomain-containing proteins regulate transcription through protein-protein interactions with chromatin and serve as scaffolding proteins for recruiting essential members of the transcriptional machinery. One such protein is the bromodomain and PHD-containing transcription factor (BPTF), the largest member of the nucleosome remodeling complex, NURF. Despite an emerging role for BPTF in regulating a diverse set of cancers, small molecule development for inhibiting the BPTF bromodomain has been lacking. Here we cross-validate three complementary biophysical assays to further the discovery of BPTF bromodomain inhibitors for chemical probe development: two direct binding assays (protein-observed 19F (PrOF) NMR and surface plasmon resonance (SPR)) and a competitive inhibition assay (AlphaScreen). We first compare the assays using three small molecules and acetylated histone peptides with reported affinity for the BPTF bromodomain. Using SPR with both unlabeled and fluorinated BPTF, we further determine that there is a minimal effect of 19F incorporation on ligand binding for future PrOF NMR experiments. To guide medicinal chemistry efforts towards chemical probe development, we subsequently evaluate two new BPTF inhibitor scaffolds with our suite of biophysical assays and rank-order compound affinities which could not otherwise be determined by PrOF NMR. Finally, we cocrystallize a subset of small molecule inhibitors and present the first published small molecule-protein structures with the BPTF bromodomain. We envision the biophysical assays described here and the structural insights from the crystallography will guide researchers towards developing selective and potent BPTF bromodomain inhibitors.

A report of iliac muscle abscess due to Mycobacterium bovis after bacillus Calmette-Guerin therapy for bladder cancer.

Bacillus Calmette-Guerin (BCG) vaccine is traditionally used for vaccination against tuberculosis. BCG vaccine contains live attenuated strain of Mycobacterium bovis. Intravesical BCG is also effective in treatment of transitional cell carcinoma of the urinary bladder. Complications after intravesical BCG immunotherapy are extremely rare. We report an iliac muscle abscess due to M bovis that developed 4 years after intravesical BCG therapy for bladder cancer. Infection with M bovis, though rare, should be considered in patients with prior BCG therapy for bladder cancer.

Molecular Basis for the N-Terminal Bromodomain-and-Extra-Terminal-Family Selectivity of a Dual Kinase-Bromodomain Inhibitor.

As regulators of transcription, epigenetic proteins that interpret post-translational modifications to N-terminal histone tails are essential for maintaining cellular homeostasis. When dysregulated, "reader" proteins become drivers of disease. In the case of bromodomains, which recognize N-ε-acetylated lysine, selective inhibition of individual bromodomain-and-extra-terminal (BET)-family bromodomains has proven challenging. We describe the >55-fold N-terminal-BET bromodomain selectivity of 1,4,5-trisubstituted-imidazole dual kinase-bromodomain inhibitors. Selectivity for the BRD4 N-terminal bromodomain (BRD4(1)) over its second bromodomain (BRD4(2)) arises from the displacement of ordered waters and the conformational flexibility of lysine-141 in BRD4(1). Cellular efficacy was demonstrated via reduction of c-Myc expression, inhibition of NF-κB signaling, and suppression of IL-8 production through potential synergistic inhibition of BRD4(1) and p38α. These dual inhibitors provide a new scaffold for domain-selective inhibition of BRD4, the aberrant function of which plays a key role in cancer and inflammatory signaling.

"Snake" shaped vegetation in right coronary artery.

Infective endocarditis is a rare cause of coronary embolism. This can result in myocardial infarction. Prompt identification is necessary as management is different from a regular myocardial infarction. Unlike in regular myocardial infarction, use of thrombolytics in this scenario could result in life-threatening complications and hence not indicated. In a patient who appears to be septic, embolic myocardial infarction should always be in the working differential diagnosis. An early transesophageal echocardiogram and cardiac catheterization could assist in diagnosis and management. We present an interesting case of a 45-year-old man who was admitted with vision loss, fevers and was found to have a non-ST segment elevation myocardial infarction. He had persistent bacteremia and developed systemic emboli. Investigation revealed mitral valve vegetation and a cardiac catheterization showed an interesting "snake"-shaped embolic vegetation in right coronary artery. He was treated with surgery to the mitral valve and antibiotics. In a septic patient with myocardial infarction, possibility of coronary embolism from vegetation should be kept in mind.

Pseudo-thrombotic thrombocytopenic purpura: A rare presentation of pernicious anemia.

CONTEXT: Schistocytes are fragmented red blood cells due to the flow of blood through damaged capillaries and indicate endothelial injury. They are typical of microangiopathic hemolytic anemia seen in life threatening conditions like disseminated intravascular coagulation or thrombotic thrombocytopenic purpura/hemolytic uremic syndrome .We report a rare sub-acute presentation of pernicious anemia with hemolysis, thrombocytopenia and numerous schistocytes that was initially diagnosed as a more serious thrombotic thrombocytopenic purpura. CASE REPORT: A 31-year-old Caucasian woman presented with fatigue and paresthesia of both feet for 1 week. Past medical history included hypertension and gastro-esophageal reflux disease. Examination revealed scleral icterus and pallor. Examination of the abdomen did not show hepatosplenomegaly. Initial laboratory tests showed severe anemia, and low platelets. Indirect bilirubin and serum Lactate De Hydrogenase were elevated. Prothrombin time, partial thromboplastin time, serum fibrinogen, and serum fibrin degradation product levels were normal. Peripheral smear revealed numerous schistocytes, anisocytosis and macro-ovalocytes. Thrombotic thrombocytopenic purpura (TTP) was suspected due to the constellation of sub-acute onset of fatigue and paresthesia along with thrombocytopenia, schistocytes and an elevated LDH. Plasmapheresis was initiated for possible TTP. However, platelet count worsened despite plasmapheresis for 4 days. On re-evaluation, vitamin B(12) was found to be low. Treatment with intra-muscular vitamin B(12) led to symptomatic and hematologic improvement. Pernicious anemia was confirmed by the presence of anti-intrinsic factor antibodies, elevated serum gastrin level and atrophic gastritis. CONCLUSION: Clinicians must be aware of unusual clinical presentation of vitamin B(12) deficiency with schistocytes as the management is simple and effective.

Internal medicine residents' acceptance of self-directed learning plans at the point of care.

OBJECTIVES: We implemented a curriculum using self-directed learning plans (SDLPs) based on clinical questions arising from the residents' practice, and we report on perceptions and attitudes from residents in internal medicine regarding the use of SDLPs conceived at point of care. METHODS: Internal medicine residents at a single community hospital in the Midwest were surveyed in 2006 regarding SDLPs. We report their perceived effectiveness in identifying knowledge gaps, the processes used to fill those gaps, and the resident outcomes using descriptive statistics. RESULTS: A total of 26 out of 37 residents (70%) responded. Most (24 of 26; 92%) perceived SDLPs helped them to identify and fill knowledge gaps and that their skills in framing questions (23 of 26; 88%), identifying resources (21 of 26; 81%), and critically appraising the evidence (20 of 26; 77%) improved through regular use. They also felt these plans led to a meaningful change in their practice or provided further direction for learning (17 of 26; 65%). Most (21 of 26; 81%) reported their intent to include point-of-care learning in their continuing education after residency. We found no significant differences in the responses of first-year compared with second- or third-year residents. CONCLUSIONS: Questions arising during patient care are strong motivators for physician self-directed learning. The residents' responses indicated that they accepted the SDLPs and intend to use them in practice. Embedding the discussion of the SDLPs in preclinic conferences has ensured sustainability during the past 5 years and has enabled us to demonstrate teaching of practice-based learning and improvement.

Chylous ascites.

CONTEXT: Chylous ascites is the accumulation of milky chyle in the peritoneal cavity. Chylous ascites has been reported after surgeries like abdominal aortic aneurysm repair, radical gastrectomy, duodenectomy, nephrectomy and Wilm's tumor resection. Our literature search did not reveal any reports of chylous ascites after a gastric ulcer resection. We report about an elderly woman with a rare complication of chylous ascites after an emergent surgery for a perforated gastric ulcer. CASE REPORT: A 70-year-old woman developed sudden respiratory distress on 5(th) post-operative day after an elective C3-C7 cervical discectomy and fusion. Her past medical history was significant for cervical spondylosis. The Computed Tomography (CT) scan of the chest revealed air under the diaphragm suspicious for hollow viscus perforation. She underwent an emergent surgery for drainage of hematoma in the neck along with an emergent laparotomy to repair a large perforated gastric ulcer distal to the gastro-esophageal junction. The patient had worsening of abdominal distention on 4(th) post-operative day. The CT scan of abdomen showed fluid collection in the abdomen. The abdominal drain revealed large amount of serous milky fluid at the rate of 1500 ml per day. The fluid analysis showed that the triglyceride level was 170 mg/dl and cholesterol level was 15 mg/dl. The fluid cultures did not grow any organism. She responded to treatment with octreotide and a diet of medium chain triglyceride oil. CONCLUSION: Any obstruction or damage to the lymphatic channels results in chylous ascites. Lymphomas, metastatic malignancies, and abdominal surgeries commonly cause chylous ascites. Ascitic fluid triglyceride level greater than 110 mg/dl is diagnostic of chylous ascites. Chylous ascites is a rare complication of a peptic ulcer resection which can be managed effectively with octreotide.

Hepatotoxicity fears contribute to underutilization of statin medications by primary care physicians.

INTRODUCTION: The safety and efficacy of hydroxymethylglutaryl CoA reductase inhibitors (statins) have been extensively demonstrated, but in clinical practice, there remains significant underutilization of these medications. The authors hypothesized that this underutilization could stem in part from fear of liver damage caused by statins. The purpose was to determine whether concern about hepatotoxicity acts as a barrier among primary care physicians to prescribing statins for patients with elevated liver transaminase values and/or underlying liver disease. METHOD: The survey included 937 primary care physicians from 138 academic centers in the United States, and the following were measured: (1) comparison of statin prescribing for patients with clinical indications and (a) no mention of liver transaminase values, (b) elevated liver transaminase values and (c) underlying liver disease; (2) correlation between perception of statin hepatotoxicity and statin prescribing. RESULTS: Seventy-one percent of respondents would prescribe statins in scenario 1, (45-year-old woman with low-density lipoprotein 240 mg/dL), whereas only 50% would prescribe statins if the baseline liver transaminase values were elevated to 1.5 times upper limit of normal (P < 0.001). This prescribing rate dropped even further to 40% in scenario 3 (55-year-old man with known coronary disease, low-density lipoprotein 250 mg/dL and hepatitis C). Thirty-seven percent of respondents had falsely elevated perceptions of statin hepatotoxicity risk, and these perceptions correlated inversely with statin prescribing. The method of survey administration prevented calculation of response rate, possibility of response bias exists. CONCLUSION: Despite extensive data documenting safety of statins, primary care physicians harbor significant hepatotoxicity concerns, and these concerns act as a barrier to statin utilization.