Myostatin induces mitochondrial metabolic alteration and typical apoptosis in cancer cells

Myostatin, a member of the transforming growth factor-β superfamily, regulates the glucose metabolism of muscle cells, while dysregulated myostatin activity is associated with a number of metabolic disorders, including muscle cachexia, obesity and type II diabetes. We observed that myostatin induced significant mitochondrial metabolic alterations and prolonged exposure of myostatin induced mitochondria-dependent apoptosis in cancer cells addicted to glycolysis. To address the underlying mechanism, we found that the protein levels of Hexokinase II (HKII) and voltage-dependent anion channel 1 (VDAC1), two key regulators of glucose metabolisms as well as metabolic stress-induced apoptosis, were negatively correlated. In particular, VDAC1 was dramatically upregulated in cells that are sensitive to myostatin treatment whereas HKII was downregulated and dissociated from mitochondria. Myostatin promoted the translocation of Bax from cytosol to mitochondria, and knockdown of VDAC1 inhibited myostatin-induced Bax translocation and apoptosis. These apoptotic changes can be partially rescued by repletion of ATP, or by ectopic expression of HKII, suggesting that perturbation of mitochondrial metabolism is causally linked with subsequent apoptosis. Our findings reveal novel function of myostatin in regulating mitochondrial metabolism and apoptosis in cancer cells.

Hypothermia protects against oxygen-glucose deprivation-induced neuronal injury by down-regulating the reverse transport of glutamate by astrocytes as mediated by neurons

Glutamate is the major mediator of excitotoxic neuronal death following cerebral ischemia. Under severe ischemic conditions, glutamate transporters can functionally reverse to release glutamate, thereby inducing further neuronal injury. Hypothermia has been shown to protect neurons from brain ischemia. However, the mechanism(s) involved remain unclear. Therefore, the aim of this study was to investigate the mechanism(s) mediating glutamate release during brain ischemia-reperfusion injury under hypothermic conditions. Neuron/astrocyte co-cultures were exposed to oxygen-glucose deprivation (OGD) at various temperatures for 2h, and cell viability was assayed 12h after reoxygenation. PI and MAP-2 staining demonstrated that hypothermia significantly decreased neuronal injury. Furthermore, [(3)H]-glutamate uptake assays showed that hypothermia protected rat primary cortical cultures against OGD reoxygenation-induced injury. Protein levels of the astrocytic glutamate transporter, GLT-1, which is primarily responsible for the clearance of extracellular glutamate, were also found to be reduced in a temperature-dependent manner. In contrast, expression of GLT-1 in astrocyte-enriched cultures was found to significantly increase following the addition of neuron-conditioned medium maintained at 37 °C, and to a lesser extent with neuron-conditioned medium at 33 °C. In conclusion, the neuroprotective effects of hypothermia against brain ischemia-reperfusion injury involve down-regulation of astrocytic GLT-1, which mediates the reverse transport of glutamate. Moreover, this process may be regulated by molecules secreted by stressed neurons.

Autologous dendritic cells combined with cytokine-induced killer cells synergize low-dose chemotherapy in elderly patients with acute myeloid leukaemia

OBJECTIVES

To investigate the possibility of culturing dendritic cells (DCs) and cytokine-induced killer (CIK) cells, obtained at initial diagnosis of AML in elderly patients, and to investigate the safety and efficacy of treatment with autologous DCs and CIK cells when administered to these patients in combination with low-dose chemo therapy.

METHODS

DCs and CIK cells obtained at initial diagnosis of AML in elderly patients were cultured and used in combination with low-dose chemo therapy to treat these patients (immunotherapy group). Elderly patients with AML treated only with low-dose chemotherapy served as the control. Before treatment and on day 7 after treatment with autologous DCs and CIK cells, T cell subsets and cytokine levels were evaluated in the immunotherapy group.

RESULTS

A total of 21 elderly patients with AML were included in the immunotherapy group and 23 in the control group. The clinical efficacy in the immunotherapy group was greater than in the control group. The percentages of T cell subsets and cytokine levels after immunotherapy treatment were significantly higher than before the treatment.

CONCLUSION

Immuno therapy with autologous DCs and CIK cells was found to be a promising candidate for treatment of AML in elderly patients.

Anatomical patterns and correlated MRI findings of non-perinatal hypoxic-ischaemic encephalopathy

Non-perinatal hypoxic-ischaemic encephalopathy (HIE) has varying anatomical patterns dependent on the type of insult, the degree and duration of cerebral hypoxia, or presence and degree of hypoperfusion. Profound insults can affect the entire cerebral cortex or just the perirolandic cortex, the cerebellum and the deep grey matter structures. Less severe insults may affect only the watershed regions. The objective of this article is to review the anatomical patterns of non-perinatal HIEs by MRI.

Impact of different particle size distributions on anaerobic digestion of the organic fraction of municipal solid waste

Particle size may significantly affect the speed and stability of anaerobic digestion, and matching the choice of particle size reduction equipment to digester type can thus determine the success or failure of the process. In the current research the organic fraction of municipal solid waste was processed using a combination of a shear shredder, rotary cutter and wet macerator to produce streams with different particle size distributions. The pre-processed waste was used in trials in semi-continuous 'wet' and 'dry' digesters at organic loading rate (OLR) up to 6kg volatile solids (VS) m(-3)day(-1). The results indicated that while difference in the particle size distribution did not change the specific biogas yield, the digester performance was affected. In the 'dry' digesters the finer particle size led to acidification and ultimately to process failure at the highest OLR. In 'wet' digestion a fine particle size led to severe foaming and the process could not be operated above 5kgVSm(-3)day(-1). Although the trial was not designed as a direct comparison between 'wet' and 'dry' digestion, the specific biogas yield of the 'dry' digesters was 90% of that produced by 'wet' digesters fed on the same waste at the same OLR.

Prediction for relapse and prognosis of newly diagnosed epilepsy

OBJECTIVE

The objective of this study was to investigate the timing of therapy initiation and other clinical factors as potential predictors for relapse and prognosis of epilepsy, based on hospital-based prospective observational data in China.

METHODS

One hundred and seventy-one newly diagnosed patients with one or more seizures were recruited and followed for at least 2 years. Kaplan-Meier survival analysis was used for calculating recurrence and remission rates. Univariate and multivariate analyses for risk factors were performed using Cox proportional hazards model.

RESULTS

Among the 171 patients analyzed, more patients had partial (54.4%) than generalized seizures (45.6%). The range of patients' age was 6-70 years, but 70% were under 16 years of age. Multiple seizure types (HR = 2.01; 95% CI, 1.31-3.10), epileptiform electroencephalogram (EEG) abnormality (HR = 1.95; 95% CI, 1.09-3.49), and >1 seizure monthly before treatment (HR = 2.74; 95% CI, 1.69-4.51) were predictors of seizure recurrence. The best negative predictors of remission were as follows: relapse (HR = 0.13; 95% CI, 0.07-0.23) and epileptiform EEG within 1 year of treatment (HR = 0.61; 95% CI, 0.39-0.97). Delayed treatment after three or more seizures did not significantly increase the risk of recurrence (P = 0.70) or remission (P = 0.31) compared with early treatment after one or two seizures.

CONCLUSIONS

Multiple seizure types, epileptiform EEG abnormality, and >1 seizure monthly before treatment predict seizure recurrence. Relapse and epileptiform EEG within 1 year of treatment predict adverse seizure outcome. Early treatment does not affect relapse or prognosis.

Carbon nanotubes enhance the internalization of drugs by cancer cells and decrease their chemoresistance to cytostatics

Etoposide is a semisynthetic, chemotherapeutic drug widely recommended to treat an extensive range of human cancers. Our studies indicate that, while etoposide is capable of killing human cancer cells, exposure to single-walled carbon nanotubes (SWCNTs) and etoposide results in enhanced cell death that appears to be synergistic and not merely additive. In this study, we used high pressure liquid chromatography and mass spectrometry to quantify the internal effective dose of etoposide when the human pancreatic cancer cell (PANC-1) was exposed to the combination of these agents. Our results unequivocally indicate that SWCNTs improve etoposide uptake and increase its capacity to kill cancer cells. We suggest that a combination of SWCNTs and etoposide may prove to be a more efficient chemotherapeutic protocol, especially because of the potential to lower toxic drug doses to levels that may be useful in decreasing adverse side effects, as well as in lowering the probability of inducing chemoresistance in exposed cancer cells.

Three-dimensional finite element analysis of mini-external fixation and Kirschner wire internal fixation in Bennett fracture treatment

OBJECTIVE

To analyze the mini-external fixation and percutaneous K-wire internal fixation for the treatment of Bennett fracture by using finite element analysis and to compare the biomechanical stability and postoperative impact of the two fixations on the fracture.

METHODS

Three-dimensional digital models of the first metacarpal bone, second metacarpal bone, and the trapezium were established using Mimics 10.01 software. A solid model and finite element models were created and analyzed using ANSYS 10.0. The same load of 100N was exerted on both the mini-external fixator and the Kirschner (K)-wire internal fixator for the treatment of Bennett fracture. Finally, the none-line solution was analyzed, and displacement nephograms were obtained.

RESULTS

The displacement nephograms of the distal and proximal fragments of the fracture obtained using the mini-external and K-wire models were established. The X/Y/Z (SUM)-component displacements of 15 nodes aligned with the articular surface fracture were obtained. The relative displacement of the distal and the proximal fragments of the fracture were calculated, and all digits of relative displacement were entered into SPSS 13.0 software. The difference between the X-component relative displacements was statistically significant. Moreover, the comparison of the Y-component, Z-component, and SUM-component relative displacements yielded statistical significance. The average relative displacement in the X-direction was 0.3214mm in the K-wire model.

CONCLUSION

Mini-external fixation is more effective than K-wire internal fixation for secure Bennett fracture stability. Both fixations have similar effects on postoperative traumatic arthritis and postoperative hand functions.

LEVEL OF EVIDENCE

1 Biomechanical studies.

Short communication: evaluation of Brucella infection of cows by PCR detection of Brucella DNA in raw milk

The collection of serum samples from cows is frequently difficult to implement in large-scale surveys, and may involve a high risk of occupational infection. This study assessed the potential of using raw milk sampling as a suitable method for use in a pilot survey of Brucella abortus infection status in cattle. Raw milk samples from 816 cows were examined. Polymerase chain reaction assays of raw milk, with primers derived from the IS711 element of the Brucella genome, were used. Of the cows, 55 were Brucella positive based on serum agglutination test (SAT) results. Polymerase chain reaction amplified Brucella DNA in 25 (45%) of the 55 SAT-positive cows. All of the 689 SAT-negative cows were found to be negative in PCR assays of their milk. Brucella infection status based on PCR results was then predicted for 72 cows from private h erds in which the brucellosis status was unknown. Subsequently, SAT verification of Brucella status was performed. There was no significant difference between predicted and actual SAT-positive rates in those 72 cows. This study indicates a relationship between Brucella detection levels obtained using milk-based PCR results and SAT results. The specific, rapid, and easy sampling procedure within milk-based PCR assaying for brucellosis detection makes the milk PCR method an attractive alternative for evaluation of B. abortus infection in cows, particularly if used as a routine screening and surveillance tool to reduce brucellosis outbreaks.

Postmenopausal hormone therapy and non-Hodgkin lymphoma: a pooled analysis of InterLymph case-control studies

BACKGROUND

Non-Hodgkin lymphoma (NHL) subtypes, diffuse large B-cell (DLBCL) and follicular lymphoma (FL) have different sex ratios and are diagnosed at ages over 60 years; DLBCL is more common in men and diagnosed at older ages than FL, which occurs more among women. This analysis of postmenopausal women examines the relationship between postmenopausal hormone therapy and NHL.

DESIGN

Self-reported use of postmenopausal hormone therapy from 2094 postmenopausal women with NHL and 2731 without were pooled across nine case-control studies (1983-2005) from North America, Europe and Japan. Study-specific odds ratios (OR) and 95% confidence intervals (CI) estimated using logistic regression were pooled using random-effects meta-analyses.

RESULTS

Postmenopausal women who used hormone therapy were at decreased risk of NHL (pooled OR = 0.79, 95% CI 0.69-0.90). Risks were reduced when the age of starting was 50 years or older. There was no clear trend with number of years of use. Current users were at decreased risk while those stopping over 2 years before diagnosis were not. Having a hysterectomy or not did not affect the risk. Favourable effects were present for DLBCL (pooled OR = 0.66, 95% CI 0.54-0.80) and FL (pooled OR = 0.82, 95% CI 0.66-1.01).

CONCLUSION

Postmenopausal hormone therapy, particularly used close to menopause, is associated with a decreased risk of NHL.

Effects of vascular endothelial cells on osteogenic differentiation of noncontact co-cultured periodontal ligament stem cells under hypoxia

BACKGROUND AND OBJECTIVE

During periodontitis or orthodontic tooth movement, the periodontal vasculature is severely impaired by chronic inflammation or excessive mechanical force. This leads to a hypoxic microenvironment of the periodontal cells and enhances the expression of various cytokines and growth factors that may regulate angiogenesis and alveolar bone remodeling. However, the role of hypoxia in regulating the communication between endothelial cells (ECs) and osteoblast progenitors during the remodeling and repair of periodontal tissue is still poorly defined. The aim of this study was to investigate the effects of vascular ECs on osteogenic differentiation, mineralization and the paracrine function of noncontact co-cultured periodontal ligament stem cells (PDLSCs) under hypoxia, and further reveal the involvement of MEK/ERK and p38 MAPK pathways in the process.

MATERIAL AND METHODS

First, PDLSCs were obtained and a noncontact co-culture system of PDLSCs and human umbilical vein endothelial cells was established. Second, the effects of different time-periods of hypoxia (2% O(2) ) on the osteogenic potential, mineralization and paracrine function of co-cultured PDLSCs were investigated. Third, ERK1/2 and p38 MAPK activities of PDLSCs under hypoxia were measured by western blotting. Finally, we employed specific MAPK inhibitors (PD98059 and SB20350) to investigate the involvement of ERK1/2 and p38 MAPK in PDLSC osteogenesis under hypoxia.

RESULTS

We observed further increased osteogenic differentiation of co-cultured PDLSCs, manifested by markedly enhanced alkaline phosphatase (ALP) activity and prostaglandin E(2) (PGE(2)) levels, vascular endothelial growth factor (VEGF) release, runt-related transcription factor 2 (Runx2) and Sp7 transcriptional and protein levels and mineralized nodule formation, compared with PDLSCs cultured alone. ERK1/2 was phosphorylated in a rapid but transient manner, whereas p38 MAPK was activated in a slow and sustained way under hypoxia. Furthermore, hypoxia-stimulated transcription and expression of osteogenic regulators (hypoxia-inducible factor-1α, ALP, Runx2, Sp7, PGE(2) and VEGF) were also inhibited by PD98059 and SB203580 to different degrees.

CONCLUSION

Further increased osteogenic differentiation and mineralization of co-cultured PDLSCs under hypoxia were regulated by MEK/ERK and p38 MAPK pathways. And the ECs-mediated paracrine of PGE(2) and VEGF may facilitate the unidirectional PDLSC-EC communication and promote PDLSCs osteogenesis.

Diuretic initiation and the acute risk of hip fracture

SUMMARY

We found the risk of hip fracture was transiently elevated around twofold shortly after initiation of a loop or thiazide diuretic drug in a case-crossover and case-control study. No statistical association was found following the initiation of a comparator medication: ACE inhibitors. Awareness of these short-term risks may reduce hip fractures.

INTRODUCTION

Little is known about the acute effects of initiating a diuretic drug on risk of fracture. We evaluated the relationship between initiating a diuretic drug and the occurrence of hip fracture.

METHODS

The study sample included 2,118,793 persons aged ≥50 years enrolled in The Health Improvement Network (THIN) between 1986 and 2010. The effect of a new start of a diuretic drug or comparator medication (ACE inhibitor) on risk of hip fracture was assessed using a case-crossover and case-control study during the 1-7, 8-14, 15-21, and 22-28 days following drug initiation.

RESULTS

Included were 28,703 individuals with an incident hip fracture over a mean of 7.9 years follow-up. In the case-crossover study, the risk of experiencing a hip fracture was increased during the first 7 days following loop diuretic drug initiation (OR = 1.8; 95 % CI, 1.2, 2.7). The elevated risk did not continue during the 8-14, 15-21, or 22-28 days following drug initiation. For thiazide diuretics, the risk of hip fracture was elevated 8-14 days after drug initiation (OR = 2.2; 95 % CI, 1.2, 3.9). No such association was observed in the 1-7, 15-21, or 22-28 days following thiazide drug initiation. ACE inhibitor initiation was not associated with a statistically significant increased risk of hip fracture. Similar results were observed using a case-control study.

CONCLUSIONS

The risk of hip fracture was transiently elevated around twofold shortly after the new start of a loop or thiazide diuretic drug. Awareness of these short-term risks may reduce hip fractures and other injurious falls in vulnerable adults.

Atrial arrhythmia, triggering events and conduction abnormalities in isolated murine RyR2-P2328S hearts

AIM

RyR2 mutations are associated with catecholaminergic polymorphic tachycardia, a condition characterized by ventricular and atrial arrhythmias. The present experiments investigate the atrial electrophysiology of homozygotic murine RyR2-P2328S (RyR2(S/S)) hearts for ectopic triggering events and for conduction abnormalities that might provide a re-entrant substrate.

METHODS

Electrocardiograph recordings were made from regularly stimulated RyR2(S/S) and wild type (WT) hearts, perfused using a novel modified Langendorff preparation. This permitted the simultaneous use of either floating intracellular microelectrodes to measure action potential (AP) parameters, or a multielectrode array to measure epicardial conduction velocity (CV).

RESULTS

RyR2(S/S) showed frequent sustained tachyarrhythmias, delayed afterdepolarizations and ectopic APs, increased interatrial conduction delays, reduced epicardial CVs and reduced maximum rates of AP depolarization ((dV/dt)(max)), despite similar effective refractory periods, AP durations and AP amplitudes. Effective interatrial CVs and (dV/dt)(max) values of APs following ectopic (S2) stimulation were lower than those of APs following regular stimulation and decreased with shortening S1S2 intervals. However, although RyR2(S/S) atria showed arrhythmias over a wider range of S1S2 intervals, the interatrial CV and (dV/dt)(max) of S2 APs provoking such arrhythmias were similar in RyR2(S/S) and WT.

CONCLUSIONS

These results suggest that abnormal intracellular Ca(2+) homoeostasis produces both arrhythmic triggers and a slow-conducting arrhythmic substrate in RyR2(S/S) atria. A similar mechanism might also contribute to arrhythmogenesis in other conditions, associated with diastolic Ca(2+) release, such as atrial fibrillation.

Pancreatic Castleman's Disease: Studies of Three Cases And A Cumulative Review of the Literature

Castleman's disease (CD) is a relatively rare and benign disorder. Pancreatic localization of CD is even more rare and is usually indistinguishable from pancreatic neoplasms. We report three cases of CD in which pancreas was all involved. One located in the tail of the pancreas, who accepted distal pancreatectomy, and the others in the head accepted enucleation. In addition, we review current data on its pathogenesis, imaging findings, diagnosis, differential diagnosis, and treatment.

Leptin overexpression in VTA trans-activates the hypothalamus whereas prolonged leptin action in either region cross-desensitizes

High-fat feeding or CNS leptin overexpression in chow-fed rats results in a region-specific cellular leptin resistance in medial basal hypothalamic regions and the ventral tegmental area (VTA). The present investigation examined the effects of targeted chronic leptin overexpression in the VTA as compared with the medial basal hypothalamus on long-term body weight homeostasis. The study also examined if this targeted intervention conserves regional leptin sensitivity or results in localized leptin resistance. Cellular leptin resistance was assessed by leptin-stimulated phosphorylation of signal transducers and activators of transcription 3 (STAT3). Tyrosine hydroxylase was measured in hypothalamus and VTA along with brown adipose tissue uncoupling protein 1. Leptin overexpression in VTA tempered HF-induced obesity, but to a slightly lesser extent than that with leptin overexpression in the hypothalamus. Moreover, the overexpression of leptin in the VTA stimulated cellular STAT3 phosphorylation in several regions of the medial basal hypothalamus, whereas verexpression in the hypothalamus did not activate STAT3 signaling in the VTA. This unidirectional trans-stimulation did not appear to involve migration of either the vector or the gene product. Long-term leptin overexpression in either the medial basal hypothalamus or VTA caused desensitization of leptin signaling in the treated region and cross-desensitization of leptin signaling in the untreated region. These results demonstrate a role of leptin receptors in the VTA in long-term body weight regulation, but the trans-activation of the hypothalamus following VTA leptin stimulation suggests that an integrative response involving both brain regions may account for the observed physiological outcomes.

Histone deacetylase inhibitors suppress mutant p53 transcription via histone deacetylase 8

Mutation of the p53 gene is the most common genetic alteration in human cancer and contributes to malignant process by enhancing transformed properties of cells and resistance to anticancer therapy. Mutant p53 is often highly expressed in tumor cells at least, in part, due to its increased half-life. However, whether mutant p53 expression is regulated by other mechanisms in tumors is unclear. Here we found that histone deacetylase (HDAC) inhibitors suppress both wild-type and mutant p53 transcription in time- and dose-dependent manners. Consistent with this, the levels of wild-type and mutant p53 proteins are decreased upon treatment with HDAC inhibitors. Importantly, we found that upon knockdown of each class I HDAC, only HDAC8 knockdown leads to decreased expression of wild-type and mutant p53 proteins and transcripts. Conversely, we found that ectopic expression of wild-type, but not mutant HDAC8, leads to increased transcription of p53. Furthermore, we found that knockdown of HDAC8 results in reduced expression of HoxA5 and consequently, attenuated ability of HoxA5 to activate p53 transcription, which can be rescued by ectopic expression of HoxA5. Because of the fact that HDAC8 is required for expression of both wild-type and mutant p53, we found that targeted disruption of HDAC8 expression remarkably triggers proliferative defect in cells with a mutant, but not wild-type, p53. Together, our data uncover a regulatory mechanism of mutant p53 transcription via HDAC8 and suggest that HDAC inhibitors and especially HDAC8-targeting agents might be explored as an adjuvant for tumors carrying a mutant p53.

Differentiation between oligodendroglioma genotypes using dynamic susceptibility contrast perfusion-weighted imaging and proton MR spectroscopy

BACKGROUND AND PURPOSE

Oligodendrogliomas with 1p/19q chromosome LOH are more sensitive to chemoradiation therapy than those with intact alleles. The usefulness of dynamic susceptibility contrast-PWI-guided ¹H-MRS in differentiating these 2 genotypes was tested in this study.

MATERIALS AND METHODS

Forty patients with oligodendrogliomas, 1p/19q LOH (n = 23) and intact alleles (n = 17), underwent MR imaging and 2D-¹H-MRS. ¹H-MRS VOI was overlaid on FLAIR images to encompass the hyperintense abnormality on the largest cross-section of the neoplasm and then overlaid on CBV maps to coregister CBV maps with ¹H-MRS VOI. rCBVmax values were obtained by measuring the CBV from each of the selected ¹H-MRS voxels in the neoplasm and were normalized with respect to contralateral white matter. Metabolite ratios with respect to ipsilateral Cr were computed from the voxel corresponding to the rCBVmax value. Logistic regression and receiver operating characteristic analyses were performed to ascertain the best model to discriminate the 2 genotypes of oligodendrogliomas. Qualitative evaluation of conventional MR imaging characteristics (patterns of tumor border, signal intensity, contrast enhancement, and paramagnetic susceptibility effect) was also performed to distinguish the 2 groups of oligodendrogliomas.

RESULTS

The incorporation of rCBVmax value and metabolite ratios (NAA/Cr, Cho/Cr, Glx/Cr, myo-inositol/Cr, and lipid + lactate/Cr) into the multivariate logistic regression model provided the best discriminatory classification with sensitivity (82.6%), specificity (64.7%), and accuracy (72%) in distinguishing 2 oligodendroglioma genotypes. Oligodendrogliomas with 1p/19q LOH were also more associated with paramagnetic susceptibility effect (P < .05).

CONCLUSIONS

Our preliminary results indicate the potential of combing PWI and ¹H-MRS to distinguish oligodendroglial genotypes.