Testosterone replacement therapy improves health-related quality of life for patients with late-onset hypogonadism: a meta-analysis of randomized controlled trials

Although testosterone replacement therapy can restore serum testosterone concentrations to normal level in late-onset hypogonadism patients, whether it can improve patients' quality of life remains uncertain. Therefore, we perform a meta-analysis of randomized controlled trials on this issue. Five randomized controlled trials total 1,212 patients were included. Fixed-effect model was used to calculate the weighted mean difference of score of Aging Males' Symptom rating scale. Our result reveals that testosterone replacement therapy improves patients' health-related quality of life in terms of the decrease in the AMS total score [WMD = -2.96 (-4.21, -1.71), p < .00001] and the psychological [WMD = -0.89 (-1.41, -0.37), p = .0008], somatic [WMD = -0.89 (-1.41, -0.37), p = .0008] and sexual [WMD = -1.29 (-1.75, -0.83), p < .00001] subscale score.

Effect of uric acid on mitochondrial function and oxidative stress in hepatocytes

Here, we investigated the effect of uric acid (UA) on hepatocyte mitochondria. Hepatocytes cultured in vitro were treated with varying concentrations of UA. The change in apoptotic activity was detected by flow cytometry. The DNA damage index 8-hydroxy-deoxy-guanosine (8-OHdG) and mitochondrial function indices succinate dehydrogenase (SDH), cytochrome C oxidase (CCO), and adenosine triphosphate (ATP) were detected by enzyme assays. Reactive oxygen species (ROS) accumulation was confirmed by a dichloro-dihydro-fluorescein diacetate assay. We observed an increase in apoptotic activity, ROS accumulation, and 8-OHdG activity in hepatocytes treated with UA for extended periods, indicating DNA damage; specifically, we observed a significant increase in these activities 48, 72, and 96 h after UA addition, compared to those observed at 24 h (P < 0.05). Cells treated with 30 mg/dL UA for 96 h showed a peak in apoptotic activity. We also observed a significant decrease in ATP, SDH, and CCO activities with the increase in uric acid concentration over time. Cells treated with 30 mg/dL UA for 96 h showed the highest ATP levels, while SDH and CCO activities at 48, 72, and 96 h post-UA treatment were significantly lower than those at 24 h (P < 0.01). Moreover, cells treated with 30 mg/dL UA showed a 0.02 ± 0.02 and 0.15 ± 0.01 mmol/ mg/min decrease in SDH and CCO levels after 72 h. Therefore, we concluded that high concentrations of UA may induce oxidative stress in hepatocyte mitochondria, increasing ROS production and ultimately resulting in mitochondrial damage.

Identification of pathway-related modules in high-grade osteosarcoma based on topological centrality of network strategy

OBJECTIVE

The objective of this paper is to identify pathway-related modules which are defined as in high-grade osteosarcoma based on topological centralities analysis of networks.

MATERIALS AND METHODS

Co-expression network was constructed by weighted gene co-expression network analysis (WGCNA) based on differentially expressed genes (DEGs). Pathway enrichment analysis was conducted by Kyoto Encyclopedia of Genes and Genomes (KEGG) database to detect pathway enriched genes. Pathway-related modules of pathway enriched genes were mined from the co-expression network. Then topological centralities (degree, closeness, stress and betweenness centrality) analyses for co-expression network and sub-networks were performed to explore hub genes. Validation of hub genes was carried out utilizing reverse transcription-polymerase chain reaction (RT-PCR) assays.

RESULTS

There were 129 nodes and 1229 edges in co-expression network. We obtained a total of 16 hub genes and 11 pathway-related modules. Module 17 (Bladder cancer module) was the most significant module, which comprising 9 of 16 hub genes and 6 pathway enriched genes, taking intersection elements (CAV1 and CCND1). RT-PCR results showed that both of CAV1 and CCND1 in high-grade osteosarcoma were significantly differentially expressed compared with normal controls.

CONCLUSIONS

This work may contribute to understanding the molecular pathogenesis and provide potential biomarkers for detections and effective therapies of high-grade osteosarcoma.

[Clinicopathologic features of solitary fibrous tumor in urogenital system]

OBJECTIVE

To study the clinicopathologic features and differential diagnosis of solitary fibrous tumor (SFT) in the urogenital system.

METHODS

The clinical data and pathologic characteristics of eight cases of SFT in the urogenital system were analyzed, and the relevant literature was reviewed.

RESULTS

The cohort included six male and two female patients, with age of onset ranging from 25 to 80 years. Five occurred in the kidney (three in the right kidney), one case each occurred in the bladder, the prostate and the spermatic cord. Most patients showed no obvious clinical symptoms or only had low back pain and swelling. The diameter of the tumor was ranged from 2.5 to 11.8 cm (median 5.2 cm). Microscopy showed at low magnification, the tumor cells were spindle-shaped and arranged in bundles or helicoid pattern. The regional mesenchymal fibroblasts showed hyperplasia, with obvious collagenization and formed hemangiopericytoma-like structure. One case showed increased mitotic figures (>5 cells/10 HPF) and focal necrosis. By immunohistochemistry, the tumor cells were positive for CD34 and STAT6 in all eight cases, CD99 and vimentin in six cases, bcl-2 in four cases and SMA in one case. All seven cases with follow-up did not show any tumor recurrence or metastasis.

CONCLUSIONS

SFT is rare in the urogenital system and most patients show good prognosis. SFT expresses CD34 and STAT6 and needs to be distinguished from other spindle cell tumors.

KLF13 regulates the differentiation-dependent human papillomavirus life cycle in keratinocytes through STAT5 and IL-8

High-risk strains of human papillomavirus (HPV) are the causative agents of cervical and anogenital cancers and are associated with 5% of all human cancers. Although prophylactic vaccines targeting a subset of HPV types are available, they are ineffective in HPV-infected individuals. Elucidation of the mechanisms controlling HPV replication may allow development of novel anti-HPV therapeutics. Infectious HPV virions are produced during terminal differentiation of host cells. The process of viral maturation requires synergistic interactions between viral and cellular proteins that leads to amplification of the viral genome and expression of late viral genes. Here we show that the transcription factor Kruppel-like factor 13 (KLF13) has a critical role in the HPV life cycle. KLF13 is overexpressed in HPV-positive keratinocytes and cervical cancer cell lines. Expression of KLF13 in normal cervical epithelium is low but increases significantly in cervical intraepithelial neoplasia and invasive squamous cervical cancer. After HPV infection, the E7 protein suppresses ubiquitin ligase FBW7 expression leading to an increase in KLF13 expression. Reduction of KLF13 with short hairpin RNA in differentiating HPV-positive cells resulted in diminished levels of viral gene expression and genome amplification. Knockdown of KLF13 also reduced the level of the transcription factor signal transducer and activator of transcription 5, which led to the downregulation of the ataxia-telangiectasia mutated DNA damage pathway and the chemokine interleukin-8 (IL-8). In addition, neutralization of IL-8 diminished viral genome amplification in differentiating HPV-positive cells. Thus, KLF13 is critical for the activation of the HPV productive life cycle and is likely involved in initiation and progression of cervical cancer.

Effect of head and jaw position on respiratory-related motion of the genioglossus

Head and jaw position influence upper airway patency and electromyographic (EMG) activity of the main upper airway dilator muscle, the genioglossus. However, it is not known whether changes in genioglossus EMG activity translate into altered muscle movement during respiration. The aim of this study was to determine the influence of head and jaw position on dilatory motion of the genioglossus in healthy adult men during quiet breathing by measuring the displacement of the posterior tongue in six positions—neutral, head extension, head rotation, head flexion, mouth opening, and mandibular advancement. Respiratory-related motion of the genioglossus was imaged with spatial modulation of magnetization (SPAMM) in 12 awake male participants. Tissue displacement was quantified with harmonic phase (HARP) analysis. The genioglossus moved anteriorly beginning immediately before or during inspiration, and there was greater movement in the oropharynx than in the velopharynx in all positions. Anterior displacements of the oropharyngeal tongue varied between neutral head position (0.81 ± 0.41 mm), head flexion (0.62 ± 0.45 mm), extension (0.39 ± 0.19 mm), axial rotation (0.39 ± 0.2 mm), mouth open (1.24 ± 0.72 mm), and mandibular advancement (1.08 ± 0.65 mm). Anteroposterior displacement increased in the mouth-open position and decreased in the rotated position relative to cross-sectional area (CSA) ( P = 0.002 and 0.02, respectively), but CSA did not independently predict anteroposterior movement overall ( P = 0.057). The findings of this study suggest that head position influences airway dilation during inspiration and may contribute to variation in airway patency in different head positions.

Development and validation of a computational finite element model of the rabbit upper airway: simulations of mandibular advancement and tracheal displacement

The mechanisms leading to upper airway (UA) collapse during sleep are complex and poorly understood. We previously developed an anesthetized rabbit model for studying UA physiology. On the basis of this body of physiological data, we aimed to develop and validate a two-dimensional (2D) computational finite element model (FEM) of the passive rabbit UA and peripharyngeal tissues. Model geometry was reconstructed from a midsagittal computed tomographic image of a representative New Zealand White rabbit, which included major soft (tongue, soft palate, constrictor muscles), cartilaginous (epiglottis, thyroid cartilage), and bony pharyngeal tissues (mandible, hard palate, hyoid bone). Other UA muscles were modeled as linear elastic connections. Initial boundary and contact definitions were defined from anatomy and material properties derived from the literature. Model parameters were optimized to physiological data sets associated with mandibular advancement (MA) and caudal tracheal displacement (TD), including hyoid displacement, which featured with both applied loads. The model was then validated against independent data sets involving combined MA and TD. Model outputs included UA lumen geometry, peripharyngeal tissue displacement, and stress and strain distributions. Simulated MA and TD resulted in UA enlargement and nonuniform increases in tissue displacement, and stress and strain. Model predictions closely agreed with experimental data for individually applied MA, TD, and their combination. We have developed and validated an FEM of the rabbit UA that predicts UA geometry and peripharyngeal tissue mechanical changes associated with interventions known to improve UA patency. The model has the potential to advance our understanding of UA physiology and peripharyngeal tissue mechanics.

MiR-485-3p and miR-485-5p suppress breast cancer cell metastasis by inhibiting PGC-1α expression

Breast cancer is the worldwide leading cause of cancer mortality in women. The majority of deaths from breast cancer arise from metastasis of local tumors. Cancer cells support their rapid proliferation by diverting metabolites into anabolic pathways, but during cancer metastasis, the proliferative program of invasive cancer cells is suspended for a migratory phenotype. In this study, we demonstrated that both mature forms of miRNA-485, miR-485-3p and miR-485-5p were involved in regulating mitochondrial respiration, cell migration and cell invasion in breast cancer cells by directly targeting and inhibiting the expression of PGC-1α. Specifically, the expression levels of both miR-485-3p and miR-485-5p were decreased in breast cancer tissues. Overexpression of miR-485-3p and miR-485-5p suppressed mitochondrial respiration and potential for cell migration and invasion in vitro, and also inhibited spontaneous metastasis of breast cancer cells in vivo. The suppression of mitochondrial respiration and cell invasion could be partially relieved by restoration of PGC-1α expression.

Longitudinal measurements of syrinx size in a rat model of posttraumatic syringomyelia

OBJECTIVE Syringomyelia pathophysiology is commonly studied using rodent models. However, in vivo studies of posttraumatic syringomyelia have been limited by the size of animals and lack of reliable noninvasive evaluation techniques. Imaging the rat spinal cord is particularly challenging because the spinal cord diameter is approximately 1-3 mm, and pathological lesions within the spinal cord parenchyma are even smaller. The standard technique has been histological evaluation, but this has its limitations. The aim of the present study was to determine whether syrinx size could be reliably measured using a preclinical high-field MRI animal system in a rat model of posttraumatic syringomyelia. METHODS The authors used an existing rat model of posttraumatic syringomyelia, which was created using a controlled pneumatic compression device to produce the initial spinal cord injury, followed by a subarachnoid injection of kaolin to produce arachnoiditis. T2-weighted MRI was performed on each animal using a 9.4-T scanner at 7, 10, and 13 weeks after injury. Animals were killed and syrinx sizes were calculated from in vivo MRI and histological studies. RESULTS MRI measurements of syrinx volume and length were closely correlated to histological measurements across all time points (Pearson product moment correlation coefficient r = ± 0.93 and 0.79, respectively). CONCLUSIONS This study demonstrates that high-field T2-weighted MRI can be used to measure syrinx size, and data correlate well with syrinx size measured using histological methods. Preclinical MRI may be a valuable noninvasive technique for tracking syrinx formation and enlargement in animal models of syringomyelia.

Changes in Rat Brain Tissue Microstructure and Stiffness during the Development of Experimental Obstructive Hydrocephalus

Understanding neural injury in hydrocephalus and how the brain changes during the course of the disease in-vivo remain unclear. This study describes brain deformation, microstructural and mechanical properties changes during obstructive hydrocephalus development in a rat model using multimodal magnetic resonance (MR) imaging. Hydrocephalus was induced in eight Sprague-Dawley rats (4 weeks old) by injecting a kaolin suspension into the cisterna magna. Six sham-injected rats were used as controls. MR imaging (9.4T, Bruker) was performed 1 day before, and at 3, 7 and 16 days post injection. T2-weighted MR images were collected to quantify brain deformation. MR elastography was used to measure brain stiffness, and diffusion tensor imaging (DTI) was conducted to observe brain tissue microstructure. Results showed that the enlargement of the ventricular system was associated with a decrease in the cortical gray matter thickness and caudate-putamen cross-sectional area (P < 0.001, for both), an alteration of the corpus callosum and periventricular white matter microstructure (CC+PVWM) and rearrangement of the cortical gray matter microstructure (P < 0.001, for both), while compression without gross microstructural alteration was evident in the caudate-putamen and ventral internal capsule (P < 0.001, for both). During hydrocephalus development, increased space between the white matter tracts was observed in the CC+PVWM (P < 0.001), while a decrease in space was observed for the ventral internal capsule (P < 0.001). For the cortical gray matter, an increase in extracellular tissue water was significantly associated with a decrease in tissue stiffness (P = 0.001). To conclude, this study characterizes the temporal changes in tissue microstructure, water content and stiffness in different brain regions and their association with ventricular enlargement. In summary, whilst diffusion changes were larger and statistically significant for majority of the brain regions studied, the changes in mechanical properties were modest. Moreover, the effect of ventricular enlargement is not limited to the CC+PVWM and ventral internal capsule, the extent of microstructural changes vary between brain regions, and there is regional and temporal variation in brain tissue stiffness during hydrocephalus development.

Direct-trauma model of posttraumatic syringomyelia with a computer-controlled motorized spinal cord impactor

OBJECTIVE The pathogenesis of posttraumatic syringomyelia remains enigmatic and is not adequately explained by current theories. Experimental investigations require a reproducible animal model that replicates the human condition. Current animal models are imperfect because of their low reliability, severe neurological deficits, or dissimilar mechanism of injury. The objective of this study was to develop a reproducible rodent model of posttraumatic syringomyelia using a spinal cord impactor that produces an injury that more closely mimics the human condition and does not produce severe neurological deficits. METHODS The study consisted of 2 parts. Seventy animals were studied overall: 20 in Experiment 1 and 48 in Experiment 2 after two rats with severe deficits were killed early. Experiment 1 aimed to determine the optimal force setting for inducing a cystic cavity without neurological deficits using a computer-controlled motorized spinal cord impactor. Twenty animals received an impact that ranged from 50 to 150 kDyn. Using the optimal force for producing an initial cyst determined from Experiment 1, Experiment 2 aimed to compare the progression of cavities in animals with and those without arachnoiditis induced by kaolin. Forty-eight animals were killed at 1, 3, 6, or 12 weeks after syrinx induction. Measurements of cavity size and maximum anteroposterior and lateral diameters were evaluated using light microscopy. RESULTS In Experiment 1, cavities were present in 95% of the animals. The duration of limb weakness and spinal cord cavity size correlated with the delivered force. The optimal force chosen for Experiment 2 was 75 kDyn. In Experiment 2, cavities occurred in 92% of the animals. Animals in the kaolin groups developed larger cavities and more vacuolations and enlarged perivascular spaces than those in the nonkaolin groups. CONCLUSIONS This impact model reliably produces cavities that resemble human posttraumatic syringomyelia and is suitable for further study of posttraumatic syringomyelia pathophysiology.

Investigation of in-body path loss in different human subjects for localization of capsule endoscope

Recent developments in capsule endoscopy have highlighted the need for accurate techniques to estimate the location of a capsule endoscope. A highly accurate location estimation of a capsule endoscope in the gastrointestinal (GI) tract in the range of several millimeters is a challenging task. This is mainly because the radio-frequency signals encounter high loss and a highly dynamic channel propagation environment. Therefore, an accurate path-loss model is required for the development of accurate localization algorithms. This paper presents an in-body path-loss model for the human abdomen region at 2.4 GHz frequency. To develop the path-loss model, electromagnetic simulations using the Finite-Difference Time-Domain (FDTD) method were carried out on two different anatomical human models. A mathematical expression for the path-loss model was proposed based on analysis of the measured loss at different capsule locations inside the small intestine. The proposed path-loss model is a good approximation to model in-body RF propagation, since the real measurements are quite infeasible for the capsule endoscopy subject.

Association between RAGE gene polymorphisms and ulcerative colitis susceptibility: a case-control study in a Chinese Han population

Ulcerative colitis (UC) is an immune-related disease with genetic predisposition. The aim of this study was to investigate the association of three polymorphisms in the receptor for advanced glycation end-products (RAGE) gene with UC risk in a Chinese population. This case-control study involved 72 UC patients and 479 age- and gender-matched healthy controls. Genotyping was performed using the polymerase chain reaction-ligase detection reaction method. Data were analyzed using the Haplo.stats program. There were no significant differences between patients and controls in the allele/genotype distributions of rs1800624 (P(allele)= 0.11; Pgenotype = 0.20), rs1800625 (P(allele) = 0.16; Pgenotype = 0.11), or rs2070600 (P(allele) = 0.37; Pgenotype = 0.65). In addition, no positive haplotypes were identified. To the best of our knowledge, the current study describes polymorphisms of RAGE in Chinese UC for the first time. We found no association between RAGE polymorphisms and the development of UC in the Chinese population.

Identification of natural recombinants derived from PCV2a and PCV2b

Porcine circovirus type 2 (PCV2) is considered to be the main pathogen in PC-associated diseases, and significantly affects the global pig-producing industry. PCV2 continuously evolves by point mutations and genome recombinations. In the present study, we aimed to further identify recombinant PCV2 strains. We used polymerase chain reaction to detect PCV2 in the carcasses of pigs with suspected infections from different regions of Guangdong Province in China. DNA was extracted from samples with confirmed infection and full- genome amplification, sequencing, phylogenetic tree construction, gene recombination detection, and sequence alignment were performed in gene recombination analysis. Our results show that recombination occurred between the strains SHC (DQ104421) and ZhuJi2003 (AY579893). The recombination resulted in three recombinants: GD003 (KM503044), GD005 (KM487708), and GD008 (KM487709). Further analyses revealed that these novel recombinants appeared to result from recombination between the PCV2a and PCV2b strains, with crossover regions located in ORF2. This study was a comprehensive analysis that used several different methods, which demonstrated that a cluster of PCV2 strains resulted from the same type of inter-genotypic recombination pattern, with a breakpoint in the structural protein coding region. The results of our study provide both information on the recombination mechanism and disease pathogenesis and useful data for the prevention of PCV2 in the swine industry.

Erythropoietin pretreatment exerts anti-inflammatory effects in hepatic ischemia/reperfusion-injured rats via suppression of the TLR2/NF-κB pathway

INTRODUCTION

The inflammatory response plays an important role in liver dysfunction after hepatic ischemia/reperfusion (I/R), which is tightly regulated by the Toll-like receptor 2 (TLR2)/nuclear factor (NF)-κB pathway; suppression of TLR2/NF-κB signaling has therefore become a promising target for anti-inflammatory treatment in hepatic I/R injury. Erythropoietin (EPO) is a glycoprotein cytokine produced primarily by the kidney that has anti-inflammatory activities. The purpose of the present study was to investigate the effect of EPO preconditioning, if any, against hepatic I/R injury in rats and its underlying mechanisms.

MATERIALS AND METHODS

Male Sprague-Dawley rats were subjected to partial (70%) hepatic ischemia for 45 minutes after pretreatment with either saline or EPO followed by 24-hour reperfusion. Hepatic injury was evaluated according to biochemical and histopathologic examinations. The expression of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6) were measured by using enzyme-linked immunosorbent assay and real-time polymerase chain reaction. The expression of nuclear translocation and phosphorylation of NF-κB p65, EPOR receptor (EPOR), p-EPOR, p-IκB-α, IκB-α, and TLR2 were determined by using Western blot analysis.

RESULTS

EPO treatment significantly improved hepatic function and histology, as indicated by reduced transaminase levels and pathologic changes. The expression of TNF-α, IL-1β, IL-6, p-IκB-α, and TLR2 was significantly decreased with up-regulation of p-EPOR by EPO. Moreover, EPO pretreatment also reduced I/R-induced the phosphorylation and nuclear translocation of NF-κB p65 subunits in liver tissue, but EPO had no influence on the expression of p65 and IκB-α.

CONCLUSIONS

These results suggest that EPO pretreatment ameliorates hepatic I/R injury, which is involved in suppressing TLR2/NF-κB-mediated inflammation.

Interaction between DNA/histone methyltransferases and their inhibitors

Epigenetic research has recently become one of the hotspots in the field of bioscience and drug design. DNA methylation and histone methylation serve a critical function in influencing gene expression and genome function. The inhibition of DNA and histone methyltransferases (DNMTs and HMTs) is a promising approach for the therapeutic treatment of numerous diseases, including cancer. This work reviews the recent achievements in methyltransferase crystallographic structure resolution and bioactive inhibitor screening. We discuss the features of DNA and HMT structures, as well as the mechanism and structure-function relationship of transferase inhibitors, to elucidate how methyltransferase and inhibitor interactions occur both internally and externally. This study briefly reviews the biological function, as well as the inhibitor discovery and development, of DNA/histone methyltransferases.

Pathway-based network analysis of myeloma tumors: monoclonal gammopathy of unknown significance, smoldering multiple myeloma, and multiple myeloma

Although many studies have been carried out on monoclonal gammopathy of unknown significances (MGUS), smoldering multiple myeloma (SMM), and multiple myeloma (MM), their classification and underlying pathogenesis are far from elucidated. To discover the relationships among MGUS, SMM, and MM at the transcriptome level, differentially expressed genes in MGUS, SMM, and MM were identified by the rank product method, and then co-expression networks were constructed by integrating the data. Finally, a pathway-network was constructed based on Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis, and the relationships between the pathways were identified. The results indicated that there were 55, 78, and 138 pathways involved in the myeloma tumor developmental stages of MGUS, SMM, and MM, respectively. The biological processes identified therein were found to have a close relationship with the immune system. Processes and pathways related to the abnormal activity of DNA and RNA were also present in SMM and MM. Six common pathways were found in the whole process of myeloma tumor development. Nine pathways were shown to participate in the progression of MGUS to SMM, and prostate cancer was the sole pathway that was involved only in MGUS and MM. Pathway-network analysis might provide a new indicator for the developmental stage diagnosis of myeloma tumors.

MR Elastography Can Be Used to Measure Brain Stiffness Changes as a Result of Altered Cranial Venous Drainage During Jugular Compression

BACKGROUND AND PURPOSE

Compressing the internal jugular veins can reverse ventriculomegaly in the syndrome of inappropriately low pressure acute hydrocephalus, and it has been suggested that this works by "stiffening" the brain tissue. Jugular compression may also alter blood and CSF flow in other conditions. We aimed to understand the effect of jugular compression on brain tissue stiffness and CSF flow.

MATERIALS AND METHODS

The head and neck of 9 healthy volunteers were studied with and without jugular compression. Brain stiffness (shear modulus) was measured by using MR elastography. Phase-contrast MR imaging was used to measure CSF flow in the cerebral aqueduct and blood flow in the neck.

RESULTS

The shear moduli of the brain tissue increased with the percentage of blood draining through the internal jugular veins during venous compression. Peak velocity of caudally directed CSF in the aqueduct increased significantly with jugular compression (P < .001). The mean jugular venous flow rate, amplitude, and vessel area were significantly reduced with jugular compression, while cranial arterial flow parameters were unaffected.

CONCLUSIONS

Jugular compression influences cerebral CSF hydrodynamics in healthy subjects and can increase brain tissue stiffness, but the magnitude of the stiffening depends on the percentage of cranial blood draining through the internal jugular veins during compression—that is, subjects who maintain venous drainage through the internal jugular veins during jugular compression have stiffer brains than those who divert venous blood through alternative pathways. These methods may be useful for studying this phenomenon in patients with the syndrome of inappropriately low-pressure acute hydrocephalus and other conditions.

Tongue stiffness is lower in patients with obstructive sleep apnea during wakefulness compared with matched control subjects

STUDY OBJECTIVES

This study aimed to determine whether tongue stiffness (shear modulus) in patients with obstructive sleep apnea (OSA) is different for controls matched for age, sex, and body mass index (BMI), and to investigate the effect of continuous positive airway pressure (CPAP) on stiffness.

DESIGN

Controlled experimental study.

SETTING

Medical research institute.

PARTICIPANTS

Patients with OSA and age-, sex-, and BMI-matched healthy controls.

MEASUREMENTS

Magnetic resonance elastography was performed in nine patients with OSA (apnea-hypopnea index (AHI) > 15 events/h) and seven controls (AHI < 10 events/h) matched for age, sex, and BMI. Six of these OSA subjects were also scanned while 10 cmH2O CPAP was applied. Mean isotropic shear modulus and anisotropic shear moduli parallel and perpendicular to the muscle fascicles in the tongue were calculated.

RESULTS

Tongue shear modulus in patients with OSA was lower than that in matched controls (2.68 ± 0.35 (mean ± standard deviation) kPa versus 2.98 ± 0.44 kPa, P < 0.001). Shear modulus decreased with increasing AHI (R = -0.496, P = 0.043), but not age, BMI, or percentage tongue fat. Anisotropic analysis revealed that reduction in stiffness was greatest parallel to the muscle fibers. CPAP had no significant effect on tongue shear modulus.

CONCLUSIONS

In awake subjects with obstructive sleep apnea, the tongue is less stiff than in similar healthy subjects and this difference occurs in the muscle fiber direction. CPAP did not significantly reduce tongue stiffness. Thus, any change in neural drive to genioglossus during wakefulness is insufficient to restore normal tongue stiffness.

A novel CO2- and SO2-tolerant dual phase composite membrane for oxygen separation

Here we report a novel, cheap, non-toxic, CO₂- and SO₂-stable dual phase composite oxygen transport membrane (Al_0.02Ga_0.02Zn_0.96O_1.02–Gd_0.1Ce_0.9O_1.95−δ) for oxygen separation.

Enhanced electrochemical performance and thermal stability of a CePO4-coated Li1.2Ni0.13Co0.13Mn0.54O2 cathode material for lithium-ion batteries

CePO₄ coating via a simple precipitation method enhances the thermal stability of the layered Li_1.2Ni_0.13Co_0.13Mn_0.54O₂ cathode material.

HIV Tat protein affects circadian rhythmicity by interfering with the circadian system

OBJECTIVES

Sleep disorders are common in patients with HIV/AIDS, and can lead to poor quality of life. Although many studies have investigated the aetiology of these disorders, it is still unclear whether impaired sleep quality is associated with HIV itself, social problems, or side effects of antiretroviral therapy (ART). Moreover, despite its known neurological associations, little is known about the role of the trans-activator of transcription (Tat) protein in sleep disorders in patients with HIV/AIDS. The purpose of this study was to test the hypothesis that the sleep quality of patients with HIV/AIDS affected by an altered circadian rhythm correlates with cerebrospinal HIV Tat protein concentration.

METHODS

Ninety-six patients with HIV/AIDS between 20 and 69 years old completed the Pittsburgh Sleep Quality Index. Their circadian rhythm parameters of blood pressure, Tat concentration in cerebrospinal fluid, melatonin concentration, CD4 cell count and HIV RNA viral load in serum were measured.

RESULTS

The circadian amplitude of systolic blood pressure and the score for sleep quality (Pittsburgh Sleep Quality Index) were negatively correlated with HIV Tat protein concentration, while the melatonin value was positively correlated with Tat protein concentration.

CONCLUSIONS

The HIV Tat protein affects circadian rhythmicity by interfering with the circadian system in patients with HIV/AIDS and further increases the melatonin excretion value. A Tat protein-related high melatonin value may counteract HIV-related poor sleep quality during the progression of HIV infection. This study provides the first clinical evidence offering an explanation for why sleep quality did not show an association with progression of HIV infection in previous studies.

Healthy humans with a narrow upper airway maintain patency during quiet breathing by dilating the airway during inspiration

A patent upper airway is essential for survival. Increased age, obesity and some upper airway anatomical features are associated with failure to maintain upper airway patency during sleep, leading to obstructive sleep apnoea. However, many healthy subjects with these risk factors do not develop this condition. The aim of this study was to determine how anatomical factors and active dilator muscle contraction contribute to upper airway patency in healthy volunteers across a broad range of age and body mass index (BMI). A 'tagged' magnetic resonance imaging technique quantified respiratory-related motion of the anterior and lateral walls of the upper airway during quiet breathing in the supine position. Fifty-two subjects aged 22-68 years with BMI from 17.5 to 40.1 kg m(-2) were studied. Higher BMI was associated with smaller airway cross-sectional area at the level of soft palate (P < 0.05). The genioglossus moved anteriorly to dilate the upper airway during inspiration. This movement increased with increasing BMI, increasing age, a smaller airway area, and steeper tongue-base angle (all P < 0.05). Motion of the lateral upper airway at the soft-palate level was variable and less strongly linked to anatomical features of the upper airway. Multiple regression indicated that anterior genioglossus motion decreased with increasing airway area (P = 0.03) and with increasing tongue-base angle (P = 0.02). These data suggest that healthy humans, including those whose anatomy places them at increased risk of airway closure, can maintain upper airway patency by dynamically dilating the airway during inspiration.