The Mll partial tandem duplication: differential, tissue-specific activity in the presence or absence of the wild-type allele

The partial tandem duplication of MLL (MLL-PTD) is found in 5% to 10% of patients with acute myeloid leukemia (AML) and normal cytogenetics. Its expression in leukemic blasts is coincident with a silenced wild-type (WT) MLL allele. We therefore generated mice expressing the Mll-PTD in the absence of Mll-WT. These Mll(PTD/-) mice die at birth unlike the normal life expectancy of Mll(PTD/WT), Mll(WT/-), and Mll(WT/WT) mice. Using Mll(WT/WT) fetal liver cells (FLC) as baseline, we compared Mll(PTD/-) with Mll(PTD/WT) FLC and found both had increased HoxA gene expression and granulocyte-macrophage colony-forming progenitor cells (CFU-GM); in contrast, only Mll(PTD/WT) FLC had increased pluripotent hemopoietic progenitors (CFU-GEMM). The similarities between Mll(PTD/WT) and Mll(PTD/-) mice suggest that the Mll-PTD mutation can up-regulate target genes in a dominant, gain-of-function fashion. The differences between these 2 genotypes suggest that in select tissues the Mll-PTD requires cooperation with the Mll-WT in the genesis of the observed abnormality.     

BCR-ABL1 mediates up-regulation of Fyn in chronic myelogenous leukemia

Chronic myelogenous leukemia (CML) invariably progresses to blast crisis, which represents the most proliferative phase of the disease. The BCR-ABL1 oncogene stimulates growth and survival pathways by phosphorylating numerous substrates, including various Src family members. Here we describe up-regulation, in contrast to activation, of the ubiquitously expressed Src kinase, Fyn, by BCR-ABL1. In a tissue microarray, Fyn expression was significantly increased in CML blast crisis compared with chronic phase. Cells overexpressing BCR-ABL1 in vitro and in vivo display an up-regulation of Fyn protein and mRNA. Knockdown of Fyn with shRNA slows leukemia cell growth, inhibits clonogenicity, and leads to increased sensitivity to imatinib, indicating that Fyn mediates CML cell proliferation. In severe combined immunodeficient (SCID) mice injected with Fyn shRNA-expressing cells, myeloid-derived cell numbers dropped by 50% and death from leukemia was delayed. Taken together, these results encourage the development of therapies targeting Fyn expression.     

UVB light upregulates prostaglandin synthases and prostaglandin receptors in mouse keratinocytes

Prostaglandins belong to a class of cyclic lipid-derived mediators synthesized from arachidonic acid via COX-1, COX-2 and various prostaglandin synthases. Members of this family include prostaglandins such as PGE₂, PGF_2α, PGD₂ and PGI₂ (prostacyclin) as well as thromboxane. In the present studies we analyzed the effects of UVB on prostaglandin production and prostaglandin synthase expression in primary cultures of undifferentiated and calcium-differentiated mouse keratinocytes. Both cell types were found to constitutively synthesize PGE₂, PGD₂ and the PGD₂ metabolite PGJ₂. Twenty-four hours after treatment with UVB (25 mJ/cm²), production of PGE₂ and PGJ₂ increased, while PGD₂ production decreased. This was associated with increased expression of COX-2 mRNA and protein. UVB (2.5–25 mJ/cm²) also caused marked increases in mRNA expression for the prostanoid synthases PGDS, mPGES-1, mPGES-2, PGFS and PGIS, as well as expression of receptors for PGE₂ (EP1 and EP2), PGD₂ (DP and CRTH2) and prostacyclin (IP). UVB was more effective in inducing COX-2 and DP in differentiated cells and EP1 and IP in undifferentiated cells. UVB readily activated keratinocyte PI-3-kinase (PI3K)/Akt, JNK and p38 MAP signaling pathways which are known to regulate COX-2 expression. While inhibition of PI3K suppressed UVB-induced mPGES-1 and CRTH2 expression, JNK inhibition suppressed mPGES-1, PGIS, EP2 and CRTH2, and p38 kinase inhibition only suppressed EP1 and EP2. These data indicate that UVB modulates expression of prostaglandin synthases and receptors by distinct mechanisms. Moreover, both the capacity of keratinocytes to generate prostaglandins and their ability to respond to these lipid mediators are stimulated by exposure to UVB.     

Extended storage of AS-1 and AS-3 leukoreduced red blood cells for 15 days after deglycerolization and resuspension in AS-3 using an automated closed system

BACKGROUND: The utilization of cryopreserved red blood cell (RBC) units had been limited by a maximum postdeglycerolization storage of 24 hours at 1 to 6 degrees C until the recent development of a closed system for the glycerolization and deglycerolization process. STUDY DESIGN AND METHODS: Sixty leukoreduced additive solution (AS), AS-1 (n = 30) and AS-3 (n = 30) RBC units from 500-mL whole blood (WB) collections were stored for 6 days, glycerolized, frozen at -70 +/- 5 degrees C for at least 14 days, thawed, deglycerolized, and stored for 15 days at 1 to 6 degrees C. Glycerolization and deglycerolization were performed with the ACP 215. In-vitro variables were tested before glycerolization, on Day 0, and Day 15 after deglycerolization storage. Forty donors were assessed for double-label 24-hour percent recovery, and T1/2 survival time was measured for 20 donors. RESULTS: Postdeglycerolization mean +/- standard deviation in-vitro RBC mass recoveries were 93 +/- 5 percent for AS-1 and 95 +/- 4 percent for AS-3. Mean hemoglobin +/- standard deviation after deglycerolization was 50.5 +/- 5.5g for AS-1 and 50.1 +/- 3.5g for AS-3. Mean hemolysis (Day 15) was 0.36 +/- 0.11 percent for AS-1 and 0.38 +/- 0.13 percent for AS-3. Double-label 24-hour in-vivo recoveries were 82.5 +/- 7.8 percent for AS-1 and 81.4 +/- 7.1 percent for AS-3. The 51Cr T1/2 value was 41.8 +/- 3.97 for AS-1 and 40.6 +/- 7.11 for AS-3. Other in-vitro variables were as expected. CONCLUSION: Leukoreduced AS-1 and AS-3 RBCs after frozen storage at -70 +/- 5 degrees C can be stored for up to 14 days when processing is performed with the ACP 215 system with resuspension of deglycerolized RBCs in AS-3.     

Sclerotherapy for intramuscular vascular malformations: A single-center experience

Background

Vascular malformations isolated to skeletal muscles are rare and often debilitating due to pain and very challenging to treat. Multi-modal management options include compression garments, medical therapy, sclerotherapy, and surgical resection.

Necrotizing soft tissue infections: a primary care review

Patients with necrotizing soft tissue infections often present initially to family physicians. These infections must be detected and treated rapidly to prevent loss of limb or a fatal outcome. Unfortunately, necrotizing soft tissue infections have no pathognomonic signs. Patients may present with some evidence of cellulitis, vesicles, bullae, edema, crepitus, erythema, and fever. They also may complain of pain that seems out of proportion to the physical findings; as the infection progresses, their pain may decrease. Magnetic resonance imaging and laboratory findings such as acidosis, anemia, electrolyte abnormalities, coagulopathy, and an elevated white blood cell count may provide clues to the diagnosis. No single organism or combination of organisms is consistently responsible for necrotizing soft tissue infections. Most infections are polymicrobial, with both anaerobic and aerobic bacteria frequently present. Fungal infections also have been reported. Generally, bacterial and toxin-related effects converge to cause skin necrosis, shock, and multisystem organ failure. Aggressive debridement of infected tissues is critical to management. Antimicrobial therapy is important but remains secondary to the removal of diseased and necrotic tissues.     

Faculty Development: Academic Opportunities for Emergency Medicine Faculty on Education Career Tracks

Medical school faculty members who specialize in the scholarship of teaching have unique requirements for academic advancement in universities with clinician-educator series. While excellence in teaching is the cornerstone of achievement, attention to traditional academic pursuits improves the likelihood of a favorable review by the institution's promotion and tenure committee. The teaching portfolio is an effective means to document performance. Ongoing faculty development and sound mentoring relationships facilitate the academic advancement of clinician-educators.     

Thromboprophylaxis and the route of administration of chemotherapy in testicular cancer patients in German-speaking countries

Purpose

Due to the excellent cure rates for testicular cancer (TC), focus has shifted towards decreasing therapy-related morbidities. Thrombosis is a frequent complication of cisplatin chemotherapy. Furthermore, the optimal route of administration for chemotherapy is still under debate. The purpose of this study was to assess the patterns of care concerning dosing and duration of thromboprophylaxis currently utilized in TC patients in German-speaking countries as well as the route of chemotherapy administration.

Methods

A standardized questionnaire was sent to all members of the German TC Study Group (GTCSG) and to all the urological university hospitals in Germany. The questionnaire was also sent to the oncologic clinics at those universities where urologists do not administer chemotherapy.

Results

The response rate was 87% (55/63). Prophylactic anticoagulation with low-molecular-weight heparin (LMWH) was administered in 94% of the clinics. The dosing of LMWH was prophylactic (85%), high prophylactic (adjusted to bodyweight) (7%), or risk adapted (9%). After completion of chemotherapy, anticoagulation was continued in 15 clinics (33%) for 2 to 24 weeks, while the remainder stopped the LMWH upon cessation of chemotherapy. Chemotherapy was administered via central venous access in 59%, peripheral IV in 27%, or both in 14% of the clinics.

Conclusions

Most of the institutions performed some form of thromboprophylaxis, although the modes of application varied by institution type and amongst the urologists and oncologists. Prospective studies are needed to evaluate the incidence, date of occurrence, and risk factors of venous thrombosis during TC chemotherapy to provide a recommendation concerning prophylactic anticoagulation.