Gene expression profiling in MDS and AML: potential and future avenues

Today, the classification systems for myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML) already incorporate cytogenetic and molecular genetic aberrations in an attempt to better reflect disease biology. However, in many MDS/AML patients no genetic aberrations have been identified yet, and even within some cytogenetically well-defined subclasses there is considerable clinical heterogeneity. Recent advances in genomics technologies such as gene expression profiling (GEP) provide powerful tools to further characterize myeloid malignancies at the molecular level, with the goal to refine the MDS/AML classification system, incorporating as yet unknown molecular genetic and epigenetic pathomechanisms, which are likely reflected by aberrant gene expression patterns. In this study, we provide a comprehensive review on how GEP has contributed to a refined molecular taxonomy of MDS and AML with regard to diagnosis, prediction of clinical outcome, discovery of novel subclasses and identification of novel therapeutic targets and novel drugs. As many challenges remain ahead, we discuss the pitfalls of this technology and its potential including future integrative studies with other genomics technologies, which will continue to improve our understanding of malignant transformation in myeloid malignancies and thereby contribute to individualized risk-adapted treatment strategies for MDS and AML patients.

Drosophila Ndfip is a novel regulator of Notch signaling

In the Drosophila wing, the Nedd4 ubiquitin ligases (E3s), dNedd4 and Su(dx), are important negative regulators of Notch signaling; they ubiquitinate Notch, promoting its endocytosis and turnover. Here, we show that Drosophila Nedd4 family interacting protein (dNdfip) interacts with the Drosophila Nedd4-like E3s. dNdfip expression dramatically enhances dNedd4 and Su(dx)-mediated wing phenotypes and further disrupts Notch signaling. dNdfip colocalizes with Notch in wing imaginal discs and with the late endosomal marker Rab7 in cultured cells. In addition, dNdfip expression in the wing leads to ectopic Notch signaling. Supporting this, expression of dNdfip suppressed Notch(+/-) wing phenotype and knockdown of dNdfip enhanced the Notch(+/-) wing phenotype. The increase in Notch activity by dNdfip is ligand independent as dNdfip expression also suppressed deltex RNAi and Serrate(+/-) wing phenotypes. The opposing effects of dNdfip expression on Notch signaling and its late endosomal localization support a model whereby dNdfip promotes localization of Notch to the limiting membrane of late endosomes allowing for activation, similar to the model previously shown with ectopic Deltex expression. When dNedd4 or Su(dx) are also present, dNdfip promotes their activity in Notch ubiquitination and internalization to the lysosomal lumen for degradation.

Pharmacology of the internal anal sphincter and its relevance to faecal incontinence

1 The internal anal sphincter (IAS) has a spontaneous tone and is the main contributor to the maintenance of faecal continence. The spontaneous resting tone exhibited by the sphincter can be modified by neurotransmitters from the autonomic and enteric nervous systems. 2 In this review, the influence of the sympathetic and parasympathetic nervous systems on IAS tone are discussed and the putative roles of nitric oxide, carbon monoxide, vasoactive intestinal peptide and adenosine triphosphate in non-adrenergic non-cholinergic transmission are considered. 3 Faecal incontinence is a common condition that places a heavy financial burden on the health service and severely affects patients' quality of life. Resting anal pressure is reduced in patients with faecal incontinence and agents that increase sphincter tone tend to relieve symptoms. The results of clinical studies of the use of phenylephrine to treat faecal incontinence are reviewed. 4 It is concluded that the IAS is a potential target for drug development for the treatment of faecal incontinence.

Risk factors for thromboembolic events in testicular cancer patients receiving chemotherapy

e16109

Background: Cancer patients are at increased risk for thromboembolic events (TTEs), and those receiving chemotherapy are at even greater risk. Clinical experience and the literature have suggested that men receiving cisplatin-based chemotherapy for metastatic germ cell tumors are at particularly high risk. As TTEs can be fatal and treatment is curative, the stakes are high. Despite this, prophylactic anticoagulation (PA) is not routinely used. Methods: All men treated with cisplatin-based chemotherapy for metastatic germ cell cancer at the London Regional Cancer Program from January 1978 to December 2007 were identified from electronic databases. Data including type and timing of TTEs were extracted by retrospective chart review. Multivariable analyses were used to identify predictors of TTEs. Results: 196 eligible patients were identified with median age 31 years (range, 15–75). No patients received PA. Thirty-two TTEs were identified in 29 patients for an overall incidence of 14.8% (95% CI, 9.8–19.8%). The majority of events were deep venous thromboses, and five patients died due to TTE or its complications. Sixteen of the patients with TTE (55.2%) were diagnosed while on treatment (defined as TTE within 6 months of chemotherapy initiation); 8 (27.6%) had their TTE prior to, and 5 (17.2%) after this time period. Age greater than 30 years (OR = 3.02; 95% CI, 1.10–8.33; p = 0.033) and elevated LDH (OR = 1.93; 95% CI, 1.07–3.48; p = 0.029) were independently associated with an increased risk of TTE. If both adverse risk factors were present, the risk of TTE on treatment was 21.7% (95% CI, 9.8–33.7%). If neither were present, the negative predictive value was 97% (95% CI, 92–100%). Conclusions: The overall TTE incidence rate of 14.8% is consistent with prior reports (8.4–19%). The risk of TTE appears greatest during chemotherapy and shortly thereafter, and nearly one in 10 patients in this group had a TTE. These data support the concept of PA for selected patients starting chemotherapy for metastatic germ cell cancer. However, the efficacy of PA and risk of hemorrhage in this group is unknown. In this cohort, patients under 30 with normal LDH were at very low risk for TTE. Confirmation of these findings to help guide the study and optimal use of PA should be pursued.

No significant financial relationships to disclose.

Bronchospasm associated with anti-TNF treatment

The aetiology of breathing difficulties in patients with inflammatory arthritis being treated with anti-TNF agents can be multi-factorial. Exacerbation of fibrosing alveolitis in patients recently commencing Infliximab has been previously described. Bronchospasm, although reported in some study patients, has not been formally investigated so far. The objective of this study is to define the incidence of bronchospasm in patients treated with anti-TNF agents and investigate details of their respiratory problems. We retrospectively reviewed the notes for 421 patients with inflammatory arthritis being treated with anti-TNF agents at our centre to identify patients who had developed respiratory symptoms during the course of this treatment (cardiac or pleural disease, thromboembolic phenomena or infection were excluded). We identified 7 patients where bronchospasm was thought to be due to treatment with anti-TNF drugs (1.7%). Four of these had to discontinue anti-TNF treatment; two of these needed oral corticosteroid therapy. Two patients were stabilised with increased inhaled beta-2 agonist and steroid, while one patient did not need treatment. All patients had significant exposure to smoking. Bronchospasm is not an uncommon side-effect of anti-TNF treatment. The aetiology of this is probably multi-factorial, but current or previous smoking appears to be a predisposing factor. The frequency and severity of bronchospasm appears to be greater than previously anticipated, all three anti-TNF agents appear to be implicated.

Charcot-Marie-Tooth (CMT) disease 1A with superimposed inflammatory polyneuropathy in children

Charcot-Marie-Tooth (CMT) disease is genetically heterogeneous and subdivided into demyelinating (CMT 1) and axonal (CMT 2) types based on neurophysiology findings. CMT1A, the commonest form associated with duplication of the PMP22 segment on chromosome 17p, often arises in childhood but is generally a slowly progressive disease. We report 2 children presenting with clinical features of an acute inflammatory demyelinating polyneuropathy (AIDP) who were subsequently diagnosed with underlying CMT1A. Both children had neurophysiology and histopathology features consistent with CMT1. Immunoglobulin treatment was initiated considering the evidence of superimposed inflammation and appeared to modify disease progression. Our findings indicate that CMT1A predisposes to a superimposed inflammatory neuropathy. Recognition of this association is difficult, particularly in children without clear family history, but of great importance as immunomodulatory treatment may improve outcome. In addition, we postulate that an underlying genetic polyneuropathy should be suspected if the recovery from AIDP is slower than expected, or incomplete.

Transcranial magnetic stimulation study of expiratory muscle weakness in acute ischemic stroke

BACKGROUND

Expiratory muscle weakness due to cerebral infarction may contribute to reduced airway clearance in stroke patients.

METHODS

Transcranial magnetic stimulation (TMS) at the vertex and over each hemisphere and magnetic stimulation over the T(10-11) spinal roots (Tw T(10)) and the phrenic nerves bilaterally (BAMPS) were performed in 15 acute ischemic stroke patients (age 68.9 +/- 9.8 years) and 16 matched controls. Surface electrodes recorded motor evoked potentials (MEPs) in the rectus abdominis (RA) and external oblique (EO) muscles bilaterally. Respiratory muscle function was assessed by measuring maximum static expiratory pressure (PE(max)) and changes in intragastric (P(gas)) and transdiaphragmatic (P(di)) pressure after voluntary cough, TMS, TwT(10), and BAMPS. Regression models were used to assess determinants of peak voluntary cough flow rates (PCFR).

RESULTS

PCFR, cough P(gas), and vertex TMS P(gas) were decreased in stroke patients compared with controls (203.6 +/- 151.1 vs 350.8 +/- 111.7 L/min, p = 0.004; 72.7 +/- 64.5 vs 163.4 +/- 55.8 cm H(2)O, p = 0.0003 and 8.7 +/- 3.3 vs 16.7 +/- 11.5 cm H(2)O, p = 0.023, respectively). There were no differences in TwT(10) P(gas) (25.2 +/- 7.8 vs 29.4 +/- 12.4 cm H(2)O, p = 0.153) or BAMPS P(di) (21.6 +/- 7.2 vs 19.2 +/- 3.4 cm H(2)O, p = 0.163). TMS P(gas) was lower (4.1 +/- 2.8 vs 6.1 +/- 1.9 cm H(2)O, p = 0.023) following TMS of the injured compared with the uninjured hemisphere in stroke patients. Age and gender adjusted PCFR correlated with P(gas) (r = 0.51, p = 0.009) and PE(max) (r = 0.46, p = 0.024). Stroke was an independent determinant of PCFR after adjusting for P(gas) and PE(max) (p = 0.031).

CONCLUSION

Ischemic cortical injury is associated with expiratory muscle weakness and may contribute to cough impairment in stroke patients.

Augmented behavioral response and enhanced synaptosomal calcium transport induced by repeated cocaine administration are decreased by calcium channel blockers

Recent studies suggest that calcium influx via L-type calcium channels is necessary for psychostimulant-induced behavioral sensitization. In addition, chronic amphetamine upregulates subtype Cav1.2-containing L-type calcium channels. In the present studies, we assessed the effect of calcium channel blockers (CCBs) on cocaine-induced behavioral sensitization and determined whether the functional activity of L-type calcium channels is altered after repeated cocaine administration. Rats were administered daily intraperitoneal injections of either flunarizine (40 mg/kg), diltiazem (40 mg/kg) or cocaine (20 mg/kg) and the combination of the CCBs and cocaine for 30 days. Motor activities were monitored on Day 1, and every 6th day during the 30-day treatment period. Daily cocaine administration produced increased locomotor activity. Maximal augmentation of behavioral response to repeated cocaine administration was observed on Day 18. Flunarizine pretreatment abolished the augmented behavioral response to repeated cocaine administration while diltiazem was less effective. Measurement of tissue monoamine levels on Day 18 revealed cocaine-induced increases in DA and 5-HT in the nucleus accumbens. By contrast to behavioral response, diltiazem was more effective in attenuating increases in monoamine levels than flunarizine. Cocaine administration for 18 days produced increases in calcium uptake in synaptosomes prepared from the nucleus accumbens and frontal cortex. Increases in calcium uptake were abolished by flunarizine and diltiazem pretreatment. Taken together, the augmented cocaine-induced behavioral response on Day 18 may be due to increased calcium uptake in the nucleus accumbens leading to increased dopamine (DA) and serotonin (5-HT) release. Flunarizine and diltiazem attenuated the behavioral response by decreasing calcium uptake and decreasing neurochemical release.