Targeting the PI3K/Akt pathway in murine MDS/MPN driven by hyperactive Ras.

Chronic and juvenile myelomonocytic leukemias (CMML and JMML) are myelodysplastic/myeloproliferative neoplasia (MDS/MPN) overlap syndromes that respond poorly to conventional treatments. Aberrant Ras activation because of NRAS, KRAS, PTPN11, CBL and NF1 mutations is common in CMML and JMML. However, no mechanism-based treatments currently exist for cancers with any of these mutations. An alternative therapeutic strategy involves targeting Ras-regulated effector pathways that are aberrantly activated in CMML and JMML, which include the Raf/MEK/ERK and phosphoinositide-3'-OH kinase (PI3K)/Akt cascades. Mx1-Cre, Kras(D12) and Mx1-Cre, Nf1(flox/)(-) mice accurately model many aspects of CMML and JMML. Treating Mx1-Cre, Kras(D12) mice with GDC-0941 (also referred to as pictilisib), an orally bioavailable inhibitor of class I PI3K isoforms, reduced leukocytosis, anemia and splenomegaly while extending survival. However, GDC-0941 treatment attenuated activation of both PI3K/Akt and Raf/MEK/ERK pathways in primary hematopoietic cells, suggesting it could be acting through suppression of Raf/MEK/ERK signals. To interrogate the importance of the PI3K/Akt pathway specifically, we treated mice with the allosteric Akt inhibitor MK-2206. This compound had no effect on Raf/MEK/ERK signaling, yet it also induced robust hematologic responses in Kras and Nf1 mice with MPN. These data support investigating PI3K/Akt pathway inhibitors as a therapeutic strategy in JMML and CMML patients.

The association between U.S. Poison Center assistance and length of stay and hospital charges.

CONTEXT: Poison centers (PCs) play an important role in poison prevention and treatment. Studies show that PCs reduce system-wide cost by reducing the number of unnecessary visits to emergency departments and by providing improved patient management. However, there remains a debate regarding the impact of PCs on patient outcomes at the hospital level. OBJECTIVE: To evaluate the impact of PC involvement on length of hospitalization and total hospital charges. MATERIALS AND METHODS: We conducted a retrospective analysis of inpatient cases treated in Illinois hospitals in 2010. We linked the Illinois Poison Center database with an Illinois hospital billing dataset and controlled for important patient-level and facility-level covariates. RESULTS: In the multivariable model, length of hospitalization among PC-assisted patients was 0.58 days shorter than that of patients without PC assistance (p < 0.001). Hospital charges for PC-assisted patients in the lower quintiles were significantly higher than patients without PC assistance (+$953; p < 0.001), but were substantially lower in the most costly quintile of patients (-$4852; p < 0.001). Balancing the higher charges for treating patients with PC assistance in the lower quintiles with the savings in the highest quintile, among inpatients there is a potential cumulative decrease of $2,078 in hospital charges per 10 patients. DISCUSSION: Among the inpatient cases, PC assistance was associated with lower total charges only among the most expensive to treat. However, this outlier group is very important when discussing medical costs. It has been repeatedly shown that the majority of treatment costs are attributable to a small fraction of patients as seen in this study.

The role of donor-specific HLA alloantibodies in liver transplantation.

The impact of donor-specific HLA alloantibodies (DSA) on short- and long-term liver transplant outcome is not clearly defined. While it is clear that not all levels of allosensitization produce overt clinical injury, and that liver allografts possess some degree of alloantibody resistance, alloantibody-mediated adverse consequences are increasingly being recognized. To better define the current state of this topic, we assembled experts to provide insights, explore controversies and develop recommendations for future research on the consequences of DSA in liver transplantation. This article summarizes the proceedings of this inaugural meeting. Several insights emerged. Acute antibody-mediated rejection (AMR), although rarely diagnosed, is increasingly understood to overlap with T cell-mediated rejection. Isolated liver allograft recipients are at increased risk of early allograft immunologic injury when preformed DSA are high titer and persist posttransplantation. Persons who undergo simultaneous liver-kidney transplantation are at risk of renal AMR when Class II DSA persist posttransplantation. Other under-appreciated DSA associations include ductopenia and fibrosis, plasma cell hepatitis, biliary strictures and accelerated fibrosis associated with recurrent liver disease. Standardized DSA testing and diagnostic criteria for both acute and chronic AMR are needed to distil existing associations into etiological processes in order to develop responsive therapeutic strategies.

The PI3K inhibitor GDC-0941 combines with existing clinical regimens for superior activity in multiple myeloma.

The phosphatidylinositol 3'-kinase (PI3K) pathway is dysregulated in multiple myeloma (MM); we therefore tested a highly selective class I PI3K inhibitor, GDC-0941, for anti-myeloma activity. Functional and mechanistic studies were first performed in MM cell lines, then extended to primary MM patient samples cultured in vitro. GDC-0941 was then assessed as a single agent and in various combinations in myeloma tumor xenograft models. We show p110 α and ß are the predominant PI3K catalytic subunits in MM and that a highly selective class I PI3K inhibitor, GDC-0941, has robust activity as a single agent to induce cell cycle arrest and apoptosis of both MM cell lines and patient myeloma cells. Mechanistic studies revealed an induction of cell cycle arrest at G0/G1, with decreased phospho-FoxO1/3a levels, decreased cyclin D1 and c-myc expression, and an increase in the cell cycle inhibitor, p27kip. Induction of apoptosis correlated with increased expression of the pro-apoptotic BH3-only protein BIM, cleaved caspase 3 and cleaved poly (ADP-ribose) polymerase (PARP). In vitro, GDC-0941 synergized with dexamethasone (Dex) and lenalidomide (combination index values of 0.3-0.4 and 0.4-0.8, respectively); in vivo GDC-0941 has anti-myeloma activity and significantly increases the activity of the standard of care agents in several murine xenograft tumor models (additional tumor growth inhibition of 37-53% (Dex) and 22-72% (lenalidomide)). These data provide a clear therapeutic hypothesis for the inhibition of PI3K and provide a rationale for clinical development of GDC-0941 in myeloma.

Predictors of elevated blood lead levels among 3-year-old Ukrainian children: a nested case-control study.

OBJECTIVES: Lead is common in the general population. However, data are lacking for the Ukraine and many other countries from the former Soviet Union (FSU). In this study we evaluate the level of blood lead among 212 Ukrainian children and determine predictors of elevated lead levels. We also describe the health effects associated with elevated blood lead. METHODS: A nested case-control study from a prospective cohort of Ukrainian 3-year-old children was conducted in March 1998. Blood assays were analyzed for lead by labs at the Centers for Disease Control and using portable examination kits. We evaluated predictors of elevated blood lead (blood levels in the upper quartile >4.65 microg/dL) using a multivariable logistic regression model. The model included socioeconomic status, parent occupation, environmental tobacco smoke, hygiene, diet, and health status. RESULTS: The geometric mean lead level was 3.15 microg/dL (range, 0.7--22.7). In our adjusted model, we observed a strong association between lead levels in the upper quartile and children whose fathers worked manual labor jobs in industries associated with lead exposures [adjusted odds ratio (OR)=2.25; P=0.025] and mothers who smoke indoors (adjusted OR=2.87; P=0.047). Daily hygiene and dietary habits were not associated with elevated lead levels. No increased risks of overall morbidity or lead-associated illness were observed (anemia, dental caries, renal disease, cardiovascular diseases, and musculoskeletal complaints). CONCLUSION: This is the first study to describe lead levels and associated variables among Ukrainian children in the peer-reviewed literature. Elevated lead levels in these children were associated with paternal occupation and mothers smoking indoors. At age 3 no adverse health effects were observed. More data are needed to determine the level of heavy metal contamination in children from the Ukraine and many other former Soviet nation-states.

Review article: the management of lower gastrointestinal bleeding.

Several recent advances have been made in the evaluation and management of acute lower gastrointestinal bleeding. This review focuses on the management of lower gastrointestinal bleeding, especially acute severe bleeding. The aim of the study was to critically review the published literature on important management issues in lower gastrointestinal bleeding, including haemodynamic resuscitation, diagnostic evaluation, and endoscopic, radiologic, and surgical therapy, and to develop an algorithm for the management of lower gastrointestinal bleeding, based on this literature review. Publications pertaining to lower gastrointestinal bleeding were identified by searches of the MEDLINE database for the years 1966 to December 2004. Clinical trials and review articles were specifically identified, and their reference citation lists were searched for additional publications not identified in the database searches. Clinical trials and current clinical recommendations were assessed by using commonly applied criteria. Specific recommendations are made based on the evidence reviewed. Approximately, 200 original and review articles were reviewed and graded. There is a paucity of high-quality evidence to guide the management of lower gastrointestinal bleeding, and current endoscopic, radiologic, and surgical practices appear to reflect local expertise and availability of services. Endoscopic literature supports the role of urgent colonoscopy and therapy where possible. Radiology literature supports the role of angiography, especially after a positive bleeding scan has been obtained. Limited surgical data support the role of segmental resection in the management of persistent lower gastrointestinal bleeding after localization by either colonoscopy or angiography. There is limited high-quality research in the area of lower gastrointestinal bleeding. Recent advances have improved the endoscopic, radiologic and surgical management of this problem. However, treatment decisions are still often based on local expertise and preference. With increased access to urgent therapeutic endoscopy for the management of acute upper gastrointestinal bleeding, diagnostic and therapeutic colonoscopy can be expected to play an increasing role in the management of acute lower gastrointestinal bleeding.

Somatic complaints and isoniazid (INH) side effects in Latino adolescents with latent tuberculosis infection (LTBI).

This study examined the potential effects of INH side effects and non-specific somatic complaints on medication adherence in 96 Latino adolescents participating in a controlled trial designed to increase isoniazid (INH) adherence. These participants (who received usual medical care) were interviewed monthly over 9 months. Participants were questioned regarding medication taking, the frequency of 15 INH-related side effects from the Physician's Desk Reference (PDR) [1], and 21 non-specific somatic complaints. Participants were aged 12-19 years, 53.1% were male, 66.7% were born in Mexico, 73% had no health insurance, and 52.5% were classified as bicultural. Approximately 70% of participants experienced at least one side effect during the trial. Side effects that occurred while taking INH were not significantly related to total number of pills taken; somatic complaints that occurred during 9 months of INH were significantly negatively related to cumulative adherence. Females reported significantly more somatic complaints at baseline than males.

Gastrointestinal bleeding in the elderly.

Among patients with acute gastrointestinal bleeding, older age is associated with an increased rate of comorbidity, greater medication use, and atypical clinical presentations. The aging of the population makes the evaluation and management of gastrointestinal bleeding in the elderly a special and increasingly common clinical challenge. The unique features and common causes of upper and lower gastrointestinal bleeding in the elderly are reviewed. Important management issues considered include hemodynamic resuscitation; anticoagulation; and medical, surgical, and endoscopic therapy.

Gastrointestinal bleeding in older people.

Aging is associated with an increased rate of comorbidity, greater medication use, and atypical clinical presentations. The aging of the population makes the evaluation and management of gastrointestinal bleeding in older people a special and increasingly common clinical challenge. The unique features and common causes of upper and lower gastrointestinal bleeding in older people are reviewed. Important management issues considered include hemodynamic resuscitation, anticoagulation, and endoscopic and surgical therapy.

Mitotic checkpoint inactivation fosters transformation in cells lacking the breast cancer susceptibility gene, Brca2.

The murine Brca2 gene encodes a nuclear protein implicated in DNA repair. Brca2 behaves as a tumor suppressor, but paradoxically, its truncation causes proliferative arrest and spontaneous chromosomal damage. Here, we report that inactivation of cell cycle checkpoints responsive to mitotic spindle disruption, by mutant forms of p53 or Bub1, relieves growth arrest and initiates neoplastic transformation in primary cells homozygous for truncated Brca2. Tumors from Brca2-deficient animals exhibit dysfunction of the spindle assembly checkpoint, accompanied by mutations in p53, Bub1, and Mad3L. The chromosomal aberrations precipitated by Brca2 truncation can be suppressed by mutant forms of Bub1 and p53. Thus, inactivating mutations in mitotic checkpoint genes likely cooperate with BRCA2 deficiency in the pathogenesis of inherited breast cancer, with important implications for treatment.

Epidemiology and the natural course of inflammatory bowel disease.

Ulcerative colitis and Crohn's disease are inflammatory disorders of the gastrointestinal tract that are distributed unevenly within populations and throughout the world. Although the exact causes of inflammatory bowel disease (IBD) remain unknown, study of the epidemiology of IBD has provided insight into pathogenesis. This article examines the geographic, ethnic, and other trends of IBD; risk factors (including genetic and environmental); and the natural history of IBD.

Increased frequency of TP53 mutations in BRCA1 and BRCA2 ovarian tumours.

We screened 81 ovarian tumours (30 BRCA1 associated, 18 BRCA2 associated, and 33 sporadic) for somatic TP53 mutations using both DNA analysis and immunostaining. TP53 mutations were significantly more frequent in tumours with mutations in BRCA1 (70% by immunostaining and 60% by DNA analysis) and BRCA2 (67% and 50%) compared to sporadic controls (39% and 30%) (P = 0.009). A higher proportion of tumours with BRCA1 and BRCA2 mutations were poorly differentiated, and TP53 mutant tumours in all categories were also more likely to be poorly differentiated. The poor differentiation of tumours with BRCA1 and BRCA2 mutations may be directly related to the role of these genes in DNA repair, and the need to overcome cell cycle checkpoints, often through loss of TP53. These results are consistent with the model of BRCA-induced tumorigenesis in which loss of checkpoint control is necessary for tumour development.

Adenocarcinoma of the esophagogastric junction.

Adenocarcinoma of the esophagogastric junction (EGJ) has increased rapidly in incidence in the latter half of the twentieth century. The increase in incidence has affected white men between the ages of 40 and 60 disproportionately. Understanding the etiology and improving treatment requires careful classification of EGJ tumors. A recent consensus conference recognized three types of EGJ adenocarcinomas: distal esophageal, cardia, and subcardia gastric. Distal esophageal adenocarcinomas are associated with Barrett's esophagus. Helicobacter pylori infection may play a role in some adenocarcinomas of the subcardia, but the association is unproven. Therapy for all types of EGJ tumors is surgical, but multimodal forms of treatment are commonly used because of the advanced stage at which these tumors often present. Several endoscopic options exist for primary therapy of early-stage tumors and for palliation.

Involvement of Brca2 in DNA repair.

Abnormalities precipitated by a targeted truncation in the murine gene Brca2 define its involvement in DNA repair. In culture, cells harboring truncated Brca2 exhibit a proliferative impediment that worsens with successive passages. Arrest in the G1 and G2/M phases is accompanied by elevated p53 and p21 expression. Increased sensitivity to genotoxic agents, particularly ultraviolet light and methylmethanesulfonate, shows that Brca2 function is essential for the ability to survive DNA damage. But checkpoint activation and apoptotic mechanisms are largely unaffected, thereby implicating Brca2 in repair. This is substantiated by the spontaneous accumulation of chromosomal abnormalities, including breaks and aberrant chromatid exchanges. These findings define a function of Brca2 in DNA repair, whose loss precipitates replicative failure, mutagen sensitivity, and genetic instability reminiscent of Bloom syndrome and Fanconi anemia.