Regulation of transcription of hypoxia-inducible factor-1α (HIF-1α) by heat shock factors HSF2 and HSF4

Hypoxia-inducible factor-1α (HIF-1α) is a principal regulator of angiogenesis and other cellular responses to hypoxic stress in both normal and tumor cells. To identify novel mechanisms that regulate expression of HIF-1α, we designed a genome-wide screen for expressed sequence tags (ESTs) that when transcribed in the antisense direction increase production of the HIF-1α target, vascular endothelial growth factor (VEGF), in human breast cancer cells. We discovered that heat shock factor (HSF) proteins 2 and 4-which previously have been implicated in the control of multiple genes that modulate cell growth and differentiation and protect against effects of environmental and cellular stresses-function together to maintain a steady state level of HIF-1α transcription and VEGF production in these cells. We show both HSFs bind to discontinuous heat shock element (HSE) sequences we identified in the HIF-1α promoter region and that downregulation of either HSF activates transcription of HIF-1α. We further demonstrate that HSF2 and HSF4 displace each other from HSF/HSE complexes in the HIF-1α promoter so that HIF-1α transcription is also activated by overexpression of either HSFs. These results argue that HSF2 and HSF4 regulate transcription of HIF-1α and that a critical balance between these HSF is required to maintain HIF-α expression in a repressed state. Our findings reveal a previously unsuspected role for HSFs in control of VEGF and other genes activated by canonical HIF-1α-mediated signaling.

Unfolded protein response suppresses cisplatin-induced apoptosis via autophagy regulation in human hepatocellular carcinoma cells

It has been shown that drug resistance is extremely common in hepatocellular carcinoma (HCC) and is one of the major problems in HCC chemotherapy. However, the detailed mechanisms remain largely unknown. We have previously shown that endoplasmic reticulum (ER) stress is involved in the tumorigenesis of HCC. Here, we demonstrated that the unfolded protein response (UPR) inhibits cisplatin-induced HCC cell apoptosis. In HCC cells, cisplatin treatment triggers the UPR, which subsequently inhibits cisplatin-induced apoptosis. Importantly, mild ER stress precondition suppresses the sensitivity of HCC cells to cisplatin-induced apoptosis through autophagy regulation. Furthermore, heat-shock protein 27 (Hsp27) is involved in the cytoprotective role of the UPR in cisplatin-induced apoptosis. We also demonstrated that Hsp27 inhibits cisplatin- induced HCC cell death through autophagy activation. Taken together, our results indicate that the UPR inhibits cisplatin-induced apoptosis in HCC cells, at least in part, by Hsp27-mediated autophagy activation.

Sonographic Assessment of Ceftriaxone-Associated Biliary Pseudolithiasis in Chinese Children

In this randomized, single-blind, case-controlled, prospective study, the incidence and outcome of ceftriaxone-associated biliary pseudolithiasis in Chinese children was evaluated via ultrasonography. A total of 108 children diagnosed with hepatobiliary infection or pneumonia were randomized to receive ceftriaxone or ceftazidime. Serial gallbladder sonograms were obtained on days 1, 5 − 7 and 10 − 14 of therapy. Gallstones were detected in 43.10% of patients in the ceftriaxone-treated group and in 2.00% of the ceftazidime-treated group. The incidence of pseudolithiasis was significantly higher in the ceftriaxone-treated than the ceftazidime-treated group. Biliary precipitation abnormalities appeared after 2 − 7 days of treatment. After gallstones were found, the drug was stopped and symptoms resolved within 1 − 2 days. This study suggests that the risk of ceftriaxone-associated biliary pseudolithiasis should be considered when treating Chinese children.

Anthracycline rechallenge using pegylated liposomal doxorubicin in patients with metastatic breast cancer: a pooled analysis using individual data from four prospective trials

BACKGROUND

The aim of this study was to determine the activity of anthracycline rechallenge using pegylated liposomal doxorubicin (PLD) in patients with metastatic breast cancer (MBC) previously treated with conventional anthracyclines.

METHODS

Pooled individual data from four prospective trials were used, and the primary end point of the pooled analysis was clinical benefit rate (CBR). The studies comprised 935 patients, of whom 274 had received PLD in the metastatic setting after prior exposure to conventional anthracyclines (rechallenge population).

RESULTS

The majority of patients were heavily pretreated. Previous anthracycline therapy was administered in the adjuvant (14%) or metastatic setting (46%), or both (40%). The overall CBR from rechallenge with PLD was 37.2% (95% CI, 32.4-42.0). In univariate analyses, the CBR was significantly higher in patients with less exposure to prior chemotherapy, in taxane-naive patients, and in patients with a favourable Eastern Cooperative Group performance status of 0 vs 1 vs 2 (53.3 vs 35.5 vs 18.2%; P<0.001). In multivariate analyses, performance status proved to be the only independent predictor of the CBR achieved with PLD rechallenge (P=0.038). There was no statistically significant difference in CBR regarding the setting, cumulative dose of and/or resistance to prior anthracyclines, or time since prior anthracycline administration.

CONCLUSION

Anthracycline rechallenge using PLD is effective in patients with MBC who have a favourable performance status, regardless of setting, resistance, cumulative dose or time since prior conventional anthracycline therapy.

Impaired interhemispheric inhibition in writer's cramp

OBJECTIVES

Reduced cortical inhibition is a feature of focal hand dystonia and this likely contributes to excessive muscle contractions. Inhibition from the opposite hemisphere, known as interhemispheric inhibition (IHI), was studied bidirectionally in 7 right-handed patients with writer's cramp (WC) and age-matched healthy controls in a cross-sectional physiologic study.

METHODS

IHI was measured with paired transcranial magnetic stimulation with the conditioning stimulus applied to the motor cortex and the test stimulus applied to the contralateral motor cortex. Surface EMG was measured in right and left first dorsal interosseous muscles during rest, and while holding a pen between the thumb and index finger at 20% maximum voluntary contraction with the right dystonia-affected hand. The time course and magnitude of IHI was studied at interstimulus intervals of 6, 8, 10, 12, 30, 40, and 50 msec between the conditioning stimulus and test stimulus.

RESULTS

In WC at rest, IHI was significantly reduced in the dystonia-affected right hand (IHI from right to left motor cortex) at both short (SIHI, 10-12 msec) and long (LIHI, 30-40 msec) intervals compared to the unaffected hand. Compared to controls, SIHI and LIHI were reduced in the dystonia-affected hand only. There was no difference in IHI between controls and WC during the task of holding a pen.

CONCLUSIONS

In WC, both SIHI and LIHI are reduced in the dystonia-affected hand compared to the unaffected hand and to healthy controls. Impaired IHI may contribute to excessive muscle contraction in WC.

Involvement of the human pedunculopontine nucleus region in voluntary movements

OBJECTIVE

The pedunculopontine nucleus region (PPNR) is being investigated as a target for deep brain stimulation (DBS) in Parkinson disease (PD), particularly for gait and postural impairment. A greater understanding of how PPNR activities and oscillations are modulated with voluntary movements is crucial to the development of neuromodulation strategies.

METHODS

We studied 7 patients with PD who underwent DBS electrode implantations in the PPNR. PPNR local field potential and EEG were recorded while patients performed self-paced wrist and ankle movements.

RESULTS

Back-averaging of the PPNR recording showed movement-related potentials before electromyography onset. Frequency analysis showed 2 discrete movement-related frequency bands in the theta (6- to 10-Hz) and beta (14- to 30-Hz) ranges. The PPNR theta band showed greater event-related desynchronization with movements in the ON than in the OFF medication state and was coupled with the sensorimotor cortices in the ON state only. Beta event-related desynchronization was observed in the PPNR during the premovement and movement execution phases in the OFF state. In contrast, premovement PPNR beta event-related synchronization occurred in the ON state. Moreover, beta band coherence between the PPNR and the midline prefrontal region was observed during movement preparation in the ON but not the OFF state.

CONCLUSIONS

Activities of PPNR change during movement preparation and execution in patients with PD. Dopaminergic medications modulate PPNR activities and promote the interactions between the cortex and PPNR. Beta oscillations may have different functions in the basal ganglia and PPNR, and may be prokinetic rather than antikinetic in the PPNR.

Evidence for excessive frontal evoked gamma oscillatory activity in schizophrenia during working memory

Gamma (gamma) oscillations (30-50 Hz) elicited during working memory (WM) are altered in schizophrenia (SCZ). However, the nature of the relationship between evoked frontal oscillatory activity, WM performance and symptom severity has yet to be ascertained. This study had two objectives. First, to extend previous studies by examining delta, theta, alpha, beta, and gamma (delta, theta, alpha, beta, and gamma) oscillatory activities during the N-back task in SCZ patients compared to healthy subjects; second, to evaluate the relationship between oscillatory activities elicited during the N-back, performance, and clinical symptoms in SCZ patients. Patients with SCZ elicited excessive frontal gamma oscillatory activity that was most pronounced in the 3-back condition compared to healthy subjects. Reduced frontal beta activity at all WM loads was also observed in patients with SCZ compared to healthy subjects. Task performance was inversely correlated with negative symptoms but not with positive symptoms. Our findings suggest that evoked frontal oscillatory activities during WM are selectively altered in the gamma and beta frequency bands that may contribute to WM impairment in SCZ patients. These findings may provide important insights into the pathophysiology underlying WM deficits, its relationship to negative symptoms and may represent a potential neurobiological marker for cognitive enhancing strategies in SCZ.

The effectiveness and cost-effectiveness of biomarkers for the prioritisation of patients awaiting coronary revascularisation: a systematic review and decision model

OBJECTIVE

To determine the effectiveness and cost-effectiveness of a range of strategies based on conventional clinical information and novel circulating biomarkers for prioritising patients with stable angina awaiting coronary artery bypass grafting (CABG).

DATA SOURCES

MEDLINE and EMBASE were searched from 1966 until 30 November 2008.

REVIEW METHODS

We carried out systematic reviews and meta-analyses of literature-based estimates of the prognostic effects of circulating biomarkers in stable coronary disease. We assessed five routinely measured biomarkers and the eight emerging (i.e. not currently routinely measured) biomarkers recommended by the European Society of Cardiology Angina guidelines. The cost-effectiveness of prioritising patients on the waiting list for CABG using circulating biomarkers was compared against a range of alternative formal approaches to prioritisation as well as no formal prioritisation. A decision-analytic model was developed to synthesise data on a range of effectiveness, resource use and value parameters necessary to determine cost-effectiveness. A total of seven strategies was evaluated in the final model.

RESULTS

We included 390 reports of biomarker effects in our review. The quality of individual study reports was variable, with evidence of small study (publication) bias and incomplete adjustment for simple clinical information such as age, sex, smoking, diabetes and obesity. The risk of cardiovascular events while on the waiting list for CABG was 3 per 10,000 patients per day within the first 90 days (184 events in 9935 patients with a mean of 59 days at risk). Risk factors associated with an increased risk, and included in the basic risk equation, were age, diabetes, heart failure, previous myocardial infarction and involvement of the left main coronary artery or three-vessel disease. The optimal strategy in terms of cost-effectiveness considerations was a prioritisation strategy employing biomarker information. Evaluating shorter maximum waiting times did not alter the conclusion that a prioritisation strategy with a risk score using estimated glomerular filtration rate (eGFR) was cost-effective. These results were robust to most alternative scenarios investigating other sources of uncertainty. However, the cost-effectiveness of the strategy using a risk score with both eGFR and C-reactive protein (CRP) was potentially sensitive to the cost of the CRP test itself (assumed to be 6 pounds in the base-case scenario).

CONCLUSIONS

Formally employing more information in the prioritisation of patients awaiting CABG appears to be a cost-effective approach and may result in improved health outcomes. The most robust results relate to a strategy employing a risk score using conventional clinical information together with a single biomarker (eGFR). The additional prognostic information conferred by collecting the more costly novel circulating biomarker CRP, singly or in combination with other biomarkers, in terms of waiting list prioritisation is unlikely to be cost-effective.

Saddlepoint approximations to the moments of multitype age-dependent branching processes, with applications

This article proposes saddlepoint approximations to the expectation and variance-covariance function of multitype age-dependent branching processes. The proposed approximations are found accurate, easy to implement, and much faster to compute than by simulating the process. Multiple applications are presented, including the analyses of clonal data on the generation of oligodendrocytes from their immediate progenitor cells, and on the proliferation of Hela cells. New estimators are also constructed to analyze clonal data. The proposed methods are finally used to approximate the distribution of the generation, which has recently found several applications in cell biology.

Imaging study of the long extracranial extension of the inferior petrosal sinus with MSCT

The aim of this study was to explore the anatomic route of Long-Inferior Petrosal Sinuses (IPS) with multi-slice spiral computed tomography, and to provide referenced evidence for the interventional preoperative evaluation for the diagnosis and treatment of skull base and sellar lesions. The route of Long-IPS and its confluence with the internal jugular vein (IJV) and the connection level of 12 IPS were shown with multi-planar reconstruction and curved multi-planar reconstruction, and the IPS length was determined. Combining the results of continuous multi-slice scanning, the diameters of the IPS at the initial segment in the jugular foreman and middle segment and the confluence segment of the IPS-IJV junction level were determined. The mean length of the Long-IPS was 66.2 +/- 17.5 mm, and the length was over 60 mm on eight sides and its peak value 100 mm. The mean diameters of the IPS were 2.4 mm +/- 0.7 mm, 2.1 mm +/- 0.4 mm, and 2.1 mm +/- 0.5 mm at the initial, middle, and confluent segments, respectively. Their diameters were equal to or greater than 2 mm at the connection level on eight sides. Furthermore, the diameter was greater than 1.6 mm at the middle and initial segments. The Long-IPS might be used as a route to the intra-cranial IPS. MSCT is helpful for showing the route and variation of the IPS and could be an effective method for preoperative evaluation of the IPS.

TWISTing stemness, inflammation and proliferation of epithelial ovarian cancer cells through MIR199A2/214

Cancer stem cells are responsible for sustaining the tumor and giving rise to proliferating and progressively differentiating cells. However, the molecular mechanisms regulating the process of cancer stem cell (CSC) differentiation is not clearly understood. Recently, we reported the isolation of the epithelial ovarian cancer (EOC) stem cells (type I/CD44+). In this study, we show that type I/CD44+ cells are characterized by low levels of both miR-199a and miR-214, whereas mature EOC cells (type II/CD44-) have higher levels of miR-199a and miR-214. Moreover, these two micro RNAs (miRNAs) are regulated as a cluster on pri-miR-199a2 within the human Dnm3os gene (GenBank FJ623959). This study identify Twist1 as a regulator of this unique miRNA cluster responsible for the regulation of the IKKbeta/NF-kappaB and PTEN/AKT pathways and its association of ovarian CSC differentiation. Our data suggest that Twist1 may be an important regulator of 'stemness' in EOC cells. The regulation of MIR199A2/214 expression may be used as a potential therapeutic approach in EOC patients.

Interaction of the antimicrobial peptide melimine with bacterial membranes

Melimine is a novel cationic peptide possessing broad-spectrum antimicrobial activity that is retained when attached to a surface, suggesting that interactions with bacterial membranes may be of primary importance to its activity. The effects of alterations in the environment on the conformation of melimine were investigated using circular dichroism and fluorescence spectra in membrane-mimetic solvents. Furthermore, the interactions of melimine with bacterial membranes of Pseudomonas aeruginosa and Staphylococcus aureus were examined using scanning electron and fluorescence microscopy, and perturbation of membrane integrity was tested by measurement of melimine-mediated diSC(3)-5 dye release from bacterial cells. Melimine has a predominantly random coil conformation that adopts a helical fold when exposed to organic solvents. However, when it is solubilised in micelles of sodium dodecyl sulphate, which are bacterial membrane-mimetic, the alpha-helical content increases to ca. 35-40%. A major effect of melimine was on the integrity of the cytoplasmic membrane both for P. aeruginosa and S. aureus. However, for P. aeruginosa the rapid loss of cytoplasmic membrane integrity correlated directly with loss of cell viability, whilst for S. aureus maximal dye release was obtained at concentrations where there was no significant loss of viability. There have been few studies to date investigating differences in the action of cationic peptides towards Gram-positive and Gram-negative bacteria. Consequently, further investigation of these mechanistic differences may allow more refined targeting of increasingly difficult-to-treat bacterial infections and/or further inform design of novel peptides with improved broad-spectrum activity.