MLL3 regulates the CDKN2A tumor suppressor locus in liver cancer

Mutations in genes encoding components of chromatin modifying and remodeling complexes are among the most frequently observed somatic events in human cancers. For example, missense and nonsense mutations targeting the mixed lineage leukemia family member 3 (MLL3, encoded by KMT2C) histone methyltransferase occur in a range of solid tumors, and heterozygous deletions encompassing KMT2C occur in a subset of aggressive leukemias. Although MLL3 loss can promote tumorigenesis in mice, the molecular targets and biological processes by which MLL3 suppresses tumorigenesis remain poorly characterized. Here we combined genetic, epigenomic, and animal modeling approaches to demonstrate that one of the mechanisms by which MLL3 links chromatin remodeling to tumor suppression is by co-activating the Cdkn2a tumor suppressor locus. Disruption of Kmt2c cooperates with Myc overexpression in the development of murine hepatocellular carcinoma (HCC), in which MLL3 binding to the Cdkn2a locus is blunted, resulting in reduced H3K4 methylation and low expression levels of the locus-encoded tumor suppressors p16/Ink4a and p19/Arf. Conversely, elevated KMT2C expression increases its binding to the CDKN2A locus and co-activates gene transcription. Endogenous Kmt2c restoration reverses these chromatin and transcriptional effects and triggers Ink4a/Arf-dependent apoptosis. Underscoring the human relevance of this epistasis, we found that genomic alterations in KMT2C and CDKN2A were associated with similar transcriptional profiles in human HCC samples. These results collectively point to a new mechanism for disrupting CDKN2A activity during cancer development and, in doing so, link MLL3 to an established tumor suppressor network.

Oral haloperidol or olanzapine intake produces distinct and region-specific increase in cannabinoid receptor levels that is prevented by high fat diet

Clinical studies show higher levels of cannabinoid CB1 receptors (CB1R) in the brain of schizophrenic patients while preclinical studies report a significant functional interaction between dopamine D2 receptors and CB1Rs as well as an upregulation of CB1Rs after antipsychotic treatment. These findings prompted us to study the effects of chronic oral intake of a first and a second generation antipsychotic, haloperidol and olanzapine, on the levels and distribution of CB1Rs in the rat brain. Rats consumed either regular chow or high-fat food and drank water, haloperidol drinking solution (1.5mg/kg), or olanzapine drinking solution (10mg/kg) for four weeks. Motor and cognitive functions were tested at the end of treatment week 3 and upon drug discontinuation. Two days after drug discontinuation, rats were euthanized and brains were processed for in vitro receptor autoradiography. In chow-fed animals, haloperidol and olanzapine increased CB1R levels in the basal ganglia and the hippocampus, in a similar, but not identical pattern. In addition, olanzapine had unique effects in CB1R upregulation in higher order cognitive areas, in the secondary somatosensory cortex, in the visual and auditory cortices and the geniculate nuclei, as well as in the hypothalamus. High fat food consumption prevented antipsychotic-induced increase in CB1R levels in all regions examined, with one exception, the globus pallidus, in which they were higher in haloperidol-treated rats. The results point towards the hypothesis that increased CB1R levels could be a confounding effect of antipsychotic medication in schizophrenia that is circumveneted by high fat feeding.

Mycoplasma pneumoniae-associated mucositis--case report and systematic review of literature

BACKGROUND

Mycoplasma pneumoniae, a bacterium known to be a common cause of pneumonia, has been documented to cause complications such as debilitating mucositis previously described as an atypical Stevens-Johnson syndrome without skin lesions. However, in the spectrum of epidermal dermatopathies, the condition is increasingly recognized as a separate entity, now termed M. pneumoniae-associated mucositis (MPAM).

OBJECTIVES

We present a case of MPAM and systemically review the literature to discuss diagnostic and therapeutic options.

METHODS

A systematic literature search was performed to find studies reporting MPAM in adults. We extracted and analysed patient demographics, disease symptomatology, diagnostic testing and treatment.

RESULTS

Eleven articles, describing 12 patients and our own patient met the predefined criteria and were analysed. Respiratory, ocular and oral symptoms were present in all patients. Therapies predominantly included antibiotics (10 of 13) and immunosuppressive treatment (9 of 13) leading to complete resolution of symptoms in all patients.

CONCLUSION

Our findings highlight that MPAM should be recognized as a distinct disease entity within the spectrum of epidermal dermatopathies. We discuss and show in our patient why M. pneumoniae IgA serum levels could prove to be more reliable diagnostic tools in the MPAM diagnosis than the widely used IgG and IgM titre levels.

Properties of HTLV-I transformed CD8+ T-cells in response to HIV-1 infection

HIV-1 infection studies of primary CD8(+) T-cells are hampered by difficulty in obtaining a significant number of targets for infection and low levels of productive infection. Further, there exists a paucity of CD8-expressing T-cell lines to address questions pertaining to the study of CD8(+) T-cells in the context of HIV-1 infection. In this study, a set of CD8(+) T-cell clones were originated through HTLV-I transformation in vitro, and the properties of these cells were examined. The clones were susceptible to T-cell tropic strains of the virus and exhibited HIV-1 production 20-fold greater than primary CD4(+) T-cells. Productive infection resulted in a decrease in expression of CD8 and CXCR4 molecules on the surface of the CD8(+) T-cell clones and antibodies to these molecules abrogated viral binding and replication. These transformed cells provide an important tool in the study of CD8(+) T-cells and may provide important insights into the mechanism(s) behind HIV-1 induced CD8(+) T-cell dysfunction.

Myocardial ischemia and adverse cardiac outcomes in cardiac patients undergoing noncardiac surgery with sevoflurane and isoflurane. Sevoflurane Ischemia Study Group

Sevoflurane is associated with less tachycardia and coronary vasodilation than isoflurane and thus might be associated with less myocardial ischemia. This multicenter study examined the incidence of myocardial ischemia and adverse cardiac outcomes in adults (40-87 yr) with cardiac disease having elective noncardiac surgery. Patients were randomized to receive either sevoflurane (S) (n = 106) or isoflurane (I) (n = 108) in conjunction with sodium thiopental, vecuronium, fentanyl, and 50%-70% N2O. Intraoperative hemodynamics were maintained within 20% of awake baseline with standard drugs. A Holter monitor was applied 3-24 h before surgery and maintained until 48 h after surgery. Electrocardiograms and blood samples for analysis of the MB isoenzyme fraction of creatine phosphokinase were obtained preoperatively and daily for 48 h postoperatively. Anesthetic exposure (1.79 +/- 0.15 [mean +/- SE] minimum alveolar concentration-hour) and duration of surgery (219 +/- 13 min) did not differ between groups. The incidence of ischemia in the pre-, intra- and postoperative periods, adverse cardiac outcomes (18% occurrence), intraoperative hemodynamic variations (+/-20% change from ward baseline), and administration of adjunct cardiovascular medications were similar between groups. In cardiac patients having noncardiac surgery, sevoflurane was comparable to isoflurane with respect to the incidence of intra- and postoperative myocardial ischemia and in the frequency of adverse cardiac outcomes.

IMPLICATIONS

Surgical patients with heart disease are at risk of heart complications, some of which could be induced by an anesthetic. We compared the incidence of cardiac complications between patients receiving sevoflurane and isoflurane. We found that the frequency of additional heart problems in cardiac patients receiving sevoflurane was not different from that associated with isoflurane.

Effects of intrathecal opioid on extubation time, analgesia, and intensive care unit stay following coronary artery bypass grafting

STUDY OBJECTIVE

To determine if intrathecal opioid decreases time to extubation after coronary artery bypass surgery without compromising postoperative analgesia.

DESIGN

Prospective randomized trial.

SETTING

Veterans Affairs Hospital.

PATIENTS

21 ASA physical status III and IV men scheduled for elective coronary bypass surgery, who had not received medications that would impair anticoagulation at the time of surgery.

INTERVENTIONS

Patients were randomized to receive 10 micrograms/kg morphine and 25 micrograms fentanyl intrathecally preoperatively (n = 12) or no intrathecal opioid (n = 9). The latter group received 25 to 50 micrograms/kg fentanyl and 0.05 to 0.1 mg/kg midaxolam intraoperatively, whereas the intrathecal opioid group received intravenous (i.v.) fentanyl and midazolam only as needed. Both groups were administered i.v. morphine and midazolam postoperatively as needed by intensive care unit (ICU) personnel who were blinded to the treatment group.

MEASUREMENTS AND MAIN RESULTS

For the first 24 hours postoperatively, pain levels (0 = none, to 10 = most severe) and sedation levels (1 = none, to 5 = unconscious) were measured hourly. The time to extubation and discharge from the ICU was recorded. ECG evidence of myocardial ischemia was noted. Pain scores were low for both groups (1.5), but the intrathecal opioid subjects exhibited less sedation than the high-dose fentanyl subjects [means +/- standard deviation (SD) of 2.3 +/- 0.4 vs. 2.8 +/- 0.5, p = 0.03]. Extubation time was 12 hours shorter in the intrathecal opioid group (2.9 +/- 5.3 vs. 14.7 +/- 6.8, p = 0.001). The five subjects with a one day ICU stay were all in the intrathecal opioid group (p = 0.04). The incidence of myocardial ischemia did not differ between the two groups.

CONCLUSIONS

Intrathecal opioid can facilitate early extubation and discharge from the ICU without compromising analgesia or increasing myocardial ischemia.

Functional activity of antibodies to the group B polysaccharide of group B streptococci elicited by a polysaccharide-protein conjugate vaccine

Group B streptococci (GBS) are a major cause of sepsis and meningitis in infants. While antibodies directed to the type-specific GBS capsule have been shown to be protective, it is less clear whether antibodies to the group B polysaccharide, a noncapsular, cell wall-associated antigen, may play a role in immunity. To investigate the functional activity of group B polysaccharide-specific antibodies, we tested sera from rabbits vaccinated with group B polysaccharide coupled to tetanus toxoid (B-TT). Anti-B-TT was weakly opsonic in vitro for a highly encapsulated type III strain, while antiserum elicited by vaccination with type III capsular polysaccharide linked to tetanus toxoid (III-TT) was a very effective opsonin. In contrast to anti-III-TT, anti-B-TT given before or after bacterial challenge was only marginally effective in protecting newborn mice against lethal infection with type III GBS. The number of C3 molecules bound to type III GBS was augmented by anti-III-TT but not by high antibody concentrations of anti-B-TT. These results suggest that the difference in opsonic activity between anti-B-TT and anti-III-TT may be due to a difference in their ability to deposit C3. In addition, the maximum number of antibody molecules bound to the bacterial surface was greater for anti-III-TT than for anti-B-TT. That anti-B-TT binds to fewer sites than anti-III-TT may explain the differences in complement activation and in opsonic and protective efficacy of antibodies to group B polysaccharide compared with antibodies to the type-specific capsular polysaccharide.