bluuebunny/crossref_metadata_2025 huggingface dataset:
A New Vibration Model for a Bearing-Rotor System considering a Bearing Structure
Authors: Wu H , Sang S-J , An Q
Published: February 2011

In the past researches about bearing-rotor systems, rolling element bearing was commonly simplified as a non-linear spring—damper with radial stiffness and damping. Such an assumption neglects the influences of bearing geometry structure on the governing equations of a bearing-rotor system and is not so reasonable. In this article, the contact stress and load distribution between roller elements and raceways are analysed using Hertz theory and the calculation method for bending moment on the bearing end faces is established; on this basis a new transfer relationship of state vectors between the two ends of bearing is obtained, and then a new transfer matrix method (TMM) for a rolling element bearing-rotor system is established. A concrete calculation example of a cylindrical roller bearing-rotor system is carried out using the new TMM. With this example, the influences of cylindrical roller bearing structure parameters (roller length, roller radius, and roller number) on a rotor system's vibration characteristics were studied in detail, and the obtained results show that the bearing geometry structure has significant influence on the rotor modal shape and the unbalanced response; such influences were also verified by finite-element method analysis.
Pediatric Asthma Management
Authors: Francisco Benjamin David , Rood Tammy Lynn
Published: February 2011

The purpose of this article is to provide a useful index to English-language, scientific publications (2007-2008) related to pediatric asthma management. The authors first surveyed abstracts to identify studies likely to affect the practice and research direction of asthma and allergy educators. To accomplish the goal of providing a comprehensive overview of the literature, only brief descriptions of selected studies are provided. The authors have not attempted to describe and critique research designs or discuss implications of findings. Expert panel reports are specifically designed to accomplish these important goals. However, approximately 5 years lapse between expert panel reports (or updates). In the interim, the authors believe that a year-by-year review of new research will be useful to many people. The draft version of Expert Panel Report 3 was released in January 2007, so the review began with that date. The authors hope this approach will stimulate interest in and improve access to the literature, facilitate collaboration, and perhaps inspire new thinking that could move the asthma and allergy educator community along a little faster in the common effort to reduce asthma burden among children.
Respiratory Viral Pathogens
Authors: Cimino Alicia L.
Published: February 2011

This clinical care update describes a variety of viruses that can lead to respiratory illness. The viruses discussed include Influenza, Parainfluenza, Respiratory Syncytical Virus, Human Metapneumovirus, Rhinovirus, Adenovirus, and Enterovirus. These viruses are responsible for many unscheduled office visits and hospitalizations in both immunocompetent and immunocompromised individuals; people with asthma are often affected. Details presented in the article include viral characteristics, signs and symptoms, complications, diagnosis, treatment, and educational recommendations for asthma educators.
A novel mechanism for egress of malarial parasites from red blood cells
Authors: Abkarian Manouk , Massiera Gladys , Berry Laurence , Roques Magali , Braun-Breton Catherine
Published: February 2011

The culminating step of the intraerythrocytic development of Plasmodium falciparum, the causative agent of malaria, is the spectacular release of multiple invasive merozoites on rupture of the infected erythrocyte membrane. This work reports for the first time that the whole process, taking place in time scales as short as 400 milliseconds, is the result of an elastic instability of the infected erythrocyte membrane. Using high-speed differential interference contrast (DIC) video microscopy and epifluorescence, we demonstrate that the release occurs in 3 main steps after osmotic swelling of the infected erythrocyte: a pore opens in ∼ 100 milliseconds, ejecting 1-2 merozoites, an outward curling of the erythrocyte membrane is then observed, ending with a fast eversion of the infected erythrocyte membrane, pushing the parasites forward. It is noteworthy that this last step shows slight differences when infected erythrocytes are adhering. We rationalize our observations by considering that during the parasite development, the infected erythrocyte membrane acquires a spontaneous curvature and we present a subsequent model describing the dynamics of the curling rim. Our results show that sequential erythrocyte membrane curling and eversion is necessary for the parasite efficient angular dispersion and might be biologically essential for fast and numerous invasions of new erythrocytes.
Lyn and PECAM-1 function as interdependent inhibitors of platelet aggregation
Authors: Ming Zhangyin , Hu Yu , Xiang Jizhou , Polewski Peter , Newman Peter J. , Newman Debra K.
Published: February 2011

Inhibition of platelet responsiveness is important to control pathologic thrombus formation. Platelet–endothelial cell adhesion molecule-1 (PECAM-1) and the Src family kinase Lyn inhibit platelet activation by the glycoprotein VI (GPVI) collagen receptor; however, it is not known whether PECAM-1 and Lyn function in the same or different inhibitory pathways. In these studies, we found that, relative to wild-type platelets, platelets derived from PECAM-1–deficient, Lyn-deficient, or PECAM-1/Lyn double-deficient mice were equally hyperresponsive to stimulation with a GPVI-specific agonist, indicating that PECAM-1 and Lyn participate in the same inhibitory pathway. Lyn was required for PECAM-1 tyrosine phosphorylation and subsequent binding of the Src homology 2 domain–containing phosphatase-2, SHP-2. These results support a model in which PECAM-1/SHP-2 complexes, formed in a Lyn-dependent manner, suppress GPVI signaling.
Programming of marginal zone B-cell fate by basic Krüppel-like factor (BKLF/KLF3)
Authors: Turchinovich Gleb , Vu Thi Thanh , Frommer Friederike , Kranich Jan , Schmid Sonja , Alles Melanie , Loubert Jean-Baptiste , Goulet Jean-Philippe , Zimber-Strobl Ursula , Schneider Pascal , Bachl Jürgen , Pearson Richard , Crossley Merlin , Agenès Fabien , Kirberg Jörg
Published: February 2011

Splenic marginal zone (MZ) B cells are a lineage distinct from follicular and peritoneal B1 B cells. They are located next to the marginal sinus where blood is released. Here they pick up antigens and shuttle the load onto follicular dendritic cells inside the follicle. On activation, MZ B cells rapidly differentiate into plasmablasts secreting antibodies, thereby mediating humoral immune responses against blood-borne type 2 T-independent antigens. As Krüppel-like factors are implicated in cell differentiation/function in various tissues, we studied the function of basic Krüppel-like factor (BKLF/KLF3) in B cells. Whereas B-cell development in the bone marrow of KLF3-transgenic mice was unaffected, MZ B-cell numbers in spleen were increased considerably. As revealed in chimeric mice, this occurred cell autonomously, increasing both MZ and peritoneal B1 B-cell subsets. Comparing KLF3-transgenic and nontransgenic follicular B cells by RNA-microarray revealed that KLF3 regulates a subset of genes that was similarly up-regulated/down-regulated on normal MZ B-cell differentiation. Indeed, KLF3 expression overcame the lack of MZ B cells caused by different genetic alterations, such as CD19-deficiency or blockade of B-cell activating factor-receptor signaling, indicating that KLF3 may complement alternative nuclear factor-κB signaling. Thus, KLF3 is a driving force toward MZ B-cell maturation.
Role of taurine on acid secretion in the rat stomach
Authors: Huang Kai-Han , Chang Chia-Chieh , Ho Jau-Der , Lu Ruey-Hwa , Tsai Li Hsueh
Published: February 2011

Background

Taurine has chemical structure similar to an inhibitory neurotransmitter, γ-aminobutyric acid (GABA). Previous studies on GABA in the stomach suggest GABAergic neuron is involved in acid secretion, but the effects of taurine are poor understood.

Methods

The effects of taurine on acid secretion, signal transduction, and localization of taurinergic neurons were determined in the rat stomach using everted whole stomach, RIA kit and immunohistochemical methods.

Results

We used antibodies against taurine-synthesizing enzyme, cysteine sulfuric acid decarboxylase (CSAD), and taurine. CSAD- and taurine-positive cells were found in the muscle and mucosal layers. Distributions of CSAD- and taurine-positive cells in both mucosal and muscle layers were heterogeneous in the stomach. Taurine at 10-9~10-4 M induced acid secretion, and the maximum secretion was at 10-5 M, 1.6-fold higher than the spontaneous secretion. Taurine-induced acid secretion was completely inhibited by bicuculline and atropine but not by cimetidine, proglumide, or strychnine. Atropine and tetrodotoxin (TTX) completely inhibited the acid secretion induced by low concentrations of taurine and partially inhibited induced by high concentrations. Verapamil, a calcium blocker agent, inhibited acid output elicited by taurine. We assumed all Ca2+ channels involved in the response to these secretagogues were equally affected by verapamil. Intracellular cAMP (adenosine 3', 5'-monophosphat) in the stomach significantly increased with taurine treatment in a dose-dependent manner. High correlation (r=0.859, p < 0.001) of taurine concentrations with cAMP was observed.

Conclusions

Our results demonstrated for the first time in taurine-induced acid secretion due to increase intracellular calcium may act through the A type of GABA receptors, which are mainly located on cholinergic neurons though cAMP pathway and partially on nonneuronal cells in the rat stomach.
Identification of alternatively spliced Dab1 and Fyn isoforms in pig
Authors: Long Huan , Bock Hans H , Lei Ting , Chai Xuejun , Yuan Jihong , Herz Joachim , Frotscher Michael , Yang Zaiqing
Published: February 2011

Background

Disabled-1 (Dab1) is an adaptor protein that is essential for the intracellular transduction of Reelin signaling, which regulates the migration and differentiation of postmitotic neurons during brain development in vertebrates. Dab1 function depends on its tyrosine phosphorylation by Src family kinases, especially Fyn.

Results

We have isolated alternatively spliced forms of porcine Dab1 from brain (sDab1) and liver (sDab1-Li) and Fyn from brain (sFyn-B) and spleen (sFyn-T). Radiation hybrid mapping localized porcine Dab1 (sDab1) and Fyn (sFyn) to chromosomes 6q31-35 and 1p13, respectively. Real-time quantitative RT-PCR (qRT-PCR) demonstrated that different isoforms of Dab1 and Fyn have tissue-specific expression patterns, and sDab1 and sFyn-B display similar temporal expression characteristics in the developing porcine cerebral cortex and cerebellum. Both sDab1 isoforms function as nucleocytoplasmic shuttling proteins. It was further shown that sFyn phosphorylates sDab1 at tyrosyl residues (Tyr) 185, 198/200 and 232, whereas sDab1-Li was phosphorylated at Tyr 185 and Tyr 197 (corresponding to Y232 in sDab1) in vitro.

Conclusions

Alternative splicing generates natural sDab1-Li that only carries Y185 and Y197 (corresponding to Y232 in sDab1) sites, which can be phosphorylated by Fyn in vitro. sDab1-Li is an isoform that is highly expressed in peripheral organs. Both isoforms are suggested to be nucleocytoplasmic shuttling proteins. Our results imply that the short splice form sDab1-Li might regulate cellular responses to different cell signals by acting as a dominant negative form against the full length sDab1 variant and that both isoforms might serve different signaling functions in different tissues.
Establishing a relationship between prolactin and altered fatty acid β-Oxidation via carnitine palmitoyl transferase 1 in breast cancer cells
Authors: Linher-Melville Katja , Zantinge Stephanie , Sanli Toran , Gerstein Hertzel , Tsakiridis Theodoros , Singh Gurmit
Published: February 2011

Background

Mammary carcinomas have been associated with a high-fat diet, and the rate of breast cancer in overweight post-menopausal women is up to 50% higher than in their normal-weight counterparts. Epidemiological studies suggest that prolactin (PRL) plays a role in the progression of breast cancer. The current study examined breast cancer as a metabolic disease in the context of altered fatty acid catabolism by examining the effect of PRL on carnitine palmitoyl transferase 1 (CPT1), an enzyme that shuttles long-chain fatty acids into the mitochondrial matrix for β-oxidation. The effect of PRL on the adenosine 5'-monophosphate-activated protein kinase (AMPK) energy sensing pathway was also investigated.

Methods

MCF-7 and MDA-MB-231 breast cancer cells and 184B5 normal breast epithelial cells treated with 100 ng/ml of PRL for 24 hr were used as in vitro models. Real-time PCR was employed to quantify changes in mRNA levels and Western blotting was carried out to evaluate changes at the protein level. A non-radioactive CPT1 enzyme activity assay was established and siRNA transfections were performed to transiently knock down specific targets in the AMPK pathway.

Results

PRL stimulation increased the expression of CPT1A (liver isoform) at the mRNA and protein levels in both breast cancer cell lines, but not in 184B5 cells. In response to PRL, a 20% increase in CPT1 enzyme activity was observed in MDA-MB-231 cells. PRL treatment resulted in increased phosphorylation of the α catalytic subunit of AMPK at Thr172, as well as phosphorylation of acetyl-CoA carboxylase (ACC) at Ser79. A siRNA against liver kinase B1 (LKB1) reversed these effects in breast cancer cells. PRL partially restored CPT1 activity in breast cancer cells in which CPT1A, LKB1, or AMPKα-1 were knocked down.

Conclusions

PRL enhances fatty acid β-oxidation by stimulating CPT1 expression and/or activity in MCF-7 and MDA-MB-231 breast cancer cells. These PRL-mediated effects are partially dependent on the LKB1-AMPK pathway, although the regulation of CPT1 is also likely to be influenced by other mechanisms. Ultimately, increased CPT1 enzyme activity may contribute to fueling the high energy demands of cancer cells. Targeting metabolic pathways that are governed by PRL, which has already been implicated in the progression of breast cancer, may be of therapeutic benefit.
Early blood glucose profile and neurodevelopmental outcome at two years in neonatal hypoxic-ischaemic encephalopathy
Authors: Nadeem Montasser , Murray Deirdre M , Boylan Geraldine B , Dempsey Eugene M , Ryan Cornelius A
Published: February 2011

Background

To examine the blood glucose profile and the relationship between blood glucose levels and neurodevelopmental outcome in term infants with hypoxic-ischaemic encephalopathy.

Methods

Blood glucose values within 72 hours of birth were collected from 52 term infants with hypoxic-ischaemic encephalopathy. Hypoglycaemia [< 46.8 mg/dL (2.6 mmol/L)] and hyperglycaemia [> 150 mg/dL (8.3 mmol/L)] were correlated to neurodevelopmental outcome at 24 months of age.

Results

Four fifths of the 468 blood samples were in the normoglycaemic range (392/468:83.8%). Of the remaining 76 samples, 51.3% were in the hypoglycaemic range and (48.7%) were hyperglycaemic. A quarter of the hypoglycaemic samples (28.2%:11/39) and a third of the hyperglycaemic samples (32.4%:12/37) were recorded within the first 30 minutes of life. Mean (SD) blood glucose values did not differ between infants with normal and abnormal outcomes [4.89(2.28) mmol/L and 5.02(2.35) mmol/L, p value = 0.15] respectively. In term infants with hypoxic-ischaemic encephalopathy, early hypoglycaemia (between 0-6 hours of life) was associated with adverse outcome at 24 months of age [OR = 5.8, CI = 1.04-32)]. On multivariate analysis to adjust for grade of HIE this association was not statistically significant. Late hypoglycaemia (6-72 hours of life) was not associated with abnormal outcome [OR = 0.22, CI (0.04-1.14)]. The occurrence of hyperglycaemia was not associated with adverse outcome.

Conclusion

During the first 72 hours of life, blood glucose profile in infants with hypoxic-ischaemic encephalopathy varies widely despite a management protocol. Early hypoglycaemia (0-6 hours of life) was associated with severe HIE, and thereby; adverse outcome.
The pandemic (H1N1) 2009 influenza virus is resistant to mannose-binding lectin
Authors: Tokunaga Hirotoshi , Ushirogawa Hiroshi , Ohuchi Masanobu
Published: February 2011

Background

Mannose-binding lectin (MBL) is an important component of innate immunity because it promotes bacterial clearance and neutralization of human influenza A viruses. Since a majority of humans have no neutralizing antibody against the pandemic (H1N1) 2009 influenza (pandemic 2009) virus, innate immunity may be crucial and MBL susceptibility may therefore influence viral pathogenesis.

Results

We examined MBL susceptibility of influenza A viruses and observed that the pandemic 2009 virus was resistant to MBL, whereas all seasonal influenza A viruses tested were susceptible. The mortality of mice infected with a seasonal H1N1 influenza virus was evidently enhanced on transient blockage of MBL activity by simultaneous inoculation of mannan, whereas mannan inoculation had no effect on mice infected with a pandemic 2009 virus. This indicates that MBL protects mice against infection with the seasonal virus but not against that with the pandemic 2009 virus.

Conclusions

These results indicate that the pandemic 2009 virus is not susceptible to MBL, an important component of innate immunity.
Administration of α-galactosylceramide impairs the survival of dendritic cell subpopulations in vivo
Authors: Simkins Helen M A , Hyde Evelyn , Farrand Kathryn J , Ong Monique L , Degli-Esposti Mariapia A , Hermans Ian F , Ronchese Franca
Published: February 2011

In this study, we examine whether recognition of α-GalCer presented on CD1d-expressing DCs and B cells in vivo elicits the cytotoxic activity of iNKT cells and elimination of α-GalCer-presenting cells. We report that i.v. injection of α-GalCer induced a decrease in the percentage and number of splenic CD8+Langerin+ DCs, while CD8– DCs were not affected. The decline in CD8+ DC numbers was clearly detectable by 15 h after α-GalCer injection, was maximal at 24–48 h, returned to normal by day 7, and was accompanied by a reduced cross-presentation of OVA protein given i.v. to specific CD8+ T cells in vitro. The decrease in the numbers of CD8+ DCs required iNKT cells but was independent of perforin, Fas, or IFN-γ, as it was observed in mice deficient in each of these molecules. In contrast, treatment with a TNF-α-neutralizing antibody was effective at reducing the decline in CD8+ DC numbers and DC activation. Treatment with immunostimulatory CpG ODN also resulted in DC activation and a decreased number of CD8+ DCs; however, the decline in DC number was a result of down-regulation of CD11c and CD8 and did not require iNKT cells or TNF-α. Although CD8+Langerin+ DCs appeared to be selectively affected by α-GalCer treatment, they were not required for early iNKT cell responses, as their prior depletion did not prevent the increase in serum TNF-α and IL-4 observed after α-GalCer treatment. Thus, iNKT cells regulate the survival of CD8+ DCs through a mechanism that does not appear to involve direct cell killing.
Colombia's National Audiences
Authors: Horowitz Adam S.
Published: February 2011

Adam S. Horowitz offers a travelogue of Colombia's cities and rural towns, surveying the social dynamics of spectatorship for a wide range of Colombian performances. He takes a night walk through the streets of Bogotá, attends a protest performance led by a venerated theater collective, explores two national festivals, and travels to rural villages where theater is created amidst the residents. Horowitz considers the relationships of Colombian spectators to the performances they attend, and the relationships of street and outdoor performances to urban geographies and politics.
Design and Operation of a Test-Platform for High-Speed Combustion Studies
Authors: New T H , Li J , Chng T L , Lim K S
Published: February 2011

This article reports on the design and operations, safety measures taken, as well as preliminary experimental results associated with a highly modular test-platform dedicated towards the study of high-speed combustion events. The test-platform was designed to be capable of controlling the overall system operations associated with and acquiring various experimental quantities simultaneously during cyclical combustion experiments. Preliminary cyclical combustion testing at 25 Hz using equivalence ratio of 1.5 non-premixed ethylene and oxygen mixtures demonstrated good repeatability and reliability of system operations. Dynamic pressure transducer measurements of a typical combustion event show that peak pressure levels ranged from 40 to 60 bar and time-of-flight velocity was as high as 2571 m/s. Compared with the estimated Chapman—Jouguet pressure and velocity for the mixture, they demonstrate that successful detonation events had been produced and captured by the test-platform. In addition, results also show that significantly higher pressure levels were produced at the upstream closed-end of the test-rig and deduced to be caused by interactions between the resulting overdriven detonations and compression waves.
Design of Spacecraft Momentum Unloading Using Discrete-Time Formulation
Authors: Kalender S , Flashner H
Published: February 2011

An approach for the design of a momentum unloading system for a spacecraft controlled by momentum exchange actuators is proposed. The approach is based on formulating momentum unloading as a control problem of a parametrically perturbed periodic system. An equivalent discrete-time robust control design problem is formulated using a point-mapping-based numerical algorithm. Established robust control analysis can then be used to develop and analyse the robustness of the unloading control law. The method is demonstrated on an Earth-pointing satellite with magnetic torquers serving as unloading actuators. Earth's magnetic field is modelled as a tilted dipole that consists of a periodic term and bounded perturbations. A discrete-time representation of the system is used to develop an unloading control law and the structured singular value theory is employed to analyse its robustness to parametric uncertainties.
A Knowledge-Based Approach for Design and Modelling of High Lift Actuation Systems
Authors: Pfennig M , Thielecke F
Published: February 2011

High lift actuation system design is a highly iterative process. Especially the preliminary design phase, which sets the course for the following design steps, is characterized by uncertain and changing data input. Despite the importance of this early design phase, a specialized and integrated computational support is not available. The objective of the research project WissBaSys is to offer knowledge-based design assistance focused on the preliminary design of high lift actuation systems. Moreover, information concerning a specific drive system architecture and component data can be used for an automated model generation leading to a significant time reduction and enhanced traceability. A capable approach for order reduction of shaft transmission models, as well as the concept for computer-aided modelling, is presented in this article.
An Analytical Study of Parametric Effects on Rotor—Vortex Interaction Noise
Authors: Shi Y-J , Zhao Q-J , Xu G-H
Published: February 2011

A numerical method for modelling the aerodynamic interaction between rotor blades and an independently generated vortex is developed. In this method, the Navier—Stokes/Euler equations are adopted for capturing the features of rotor blade—vortex interaction (BVI) flow and the overset grids technique is used for multi-zone solution. To incorporate the effects of the vortex in the solution, a generalized grid-velocity approach is presented to simplify the computations. The acoustic prediction is based on the well-known Ffowcs Williams-Hawkings (FW-H) equation for acoustic pressure. By this method developed, a parametric study is performed to examine the effects of the vortex strength, miss-distance, core-radius, oblique interaction, and interaction angle in a blade-shaft plane on BVI noise. The results indicate that the increase in miss-distance, core-radius, obliqueness of interaction, or interaction angle in a blade-shaft plane is an effective approach to reduce BVI noise, makes the BVI noise less impulsive (lower high harmonic content in noise energy) and increases the high noise encompassed area. However, the decrease in vortex strength changes only the magnitude of noise, not its distribution in different harmonics. The research also indicates that oblique interaction in a rotor plane has a significant effect on radiation directionality, while other parameters show little impact on it.
Oxidation of Guanosine to the Imidazolone Derivative via Proton-coupled Electron Transfer to Hydroperoxy Radical Derived from Superoxide
Authors: Murakami Hiroya , Esaka Yukihiro , Nakayama Tatsushi , Uno Bunji
Published: February 2011

Oxidation of guanosine (G) with electrochemically generated superoxide (O2•−) leads to the imidazolone (Iz) derivative as a single-electron oxidation product of G. A crucial step in the mechanism of the oxidation is the proton-coupled electron transfer (PCET) from G to the hydroperoxy radical (HO2•) that is derived from O2•−.
Matrix-Assisted Laser Desorption/Ionization Post-Source Decay Fragmentation of the Cystine-Containing Amphibian Peptides with Novel Cysteine Tags
Authors: Vorontsov E.A. , Samgina T.Yu. , Gorshkov V.A. , Poljakov N.B. , Nifant'ev I.E. , Lebedev A.T.
Published: February 2011

Long disulfide-containing peptides, brevinins 1E and 2Ec, from the skin secretion of the frog Rana ridibunda were reduced and alkylated with ten novel and three known derivatizing agents. Nine of novel reagents are maleimide derivatives. The peptides were also reduced with dithiothreitol directly on a matrix-assisted laser desorption/ionization (MALDI) target without alkylation. Modified samples were subjected to a MALDI–post-source decay study. Procedures, fragmentation patterns, fragment ion signal abundances and sequence coverage for two peptides modified with 13 tags (or on-plate reduced) are described. The fast on-plate procedure for reduction/alkylation was applied to a crude secretion from Rana ridibunda, providing intense signals of derivatized peptides. The corresponding ions may be used for the tandem mass spectrometry sequencing procedure.
Emergence of raltegravir-resistant HIV-1 in the central nervous system
Authors: Watanabe K , Honda M , Watanabe T , Tsukada K , Teruya K , Kikuchi Y , Oka S , Gatanaga H
Published: February 2011

Integrase inhibitor-resistant HIV-1 was detected in the cerebrospinal fluid, but not in the plasma of a 42-year-old man with HIV encephalopathy treated with a raltegravir (RAL)-containing regimen. Raltegravir resistance may develop in the central nervous system when the virus is already multi-drug resistant because of different penetration into cerebrospinal fluid of individual antiretroviral agents.
A cross-sectional study of risk factors for HIV among pregnant women in Guatemala City, Guatemala: lessons for prevention
Authors: Johri M , Morales R E , Hoch J S , Samayoa B E , Sommen C , Grazioso C F , Boivin J-F , Matta I J Barrios , Diaz E L Baide , Arathoon E G
Published: February 2011

Although the Central American HIV epidemic is concentrated in high-risk groups, HIV incidence is increasing in young women. From 2005 to 2007, we conducted a cross-sectional study of pregnant women in a large public hospital and an HIV clinic in Guatemala City to describe risk factors for HIV infection and inform prevention strategies. For 4629 consenting patients, HIV status was laboratory-confirmed and participant characteristics were assessed by interviewer-administered questionnaires. Lifetime number of sexual partners ranged from 1 to 99, with a median (interquartile range) of 1 (1, 2). 2.6% (120) reported exchanging sex for benefits; 0.1% (3) were sex workers, 2.3% (106) had used illegal drugs, 31.1% (1421) planned their pregnancy and 31.8% (1455) experienced abuse. In logistic regression analyses, HIV status was predicted by one variable describing women's behaviour (lifetime sexual partners) and three variables describing partner risks (partner HIV+ , migrant worker or suspected unfaithful). Women in our sample exhibited few behavioural risks for HIV but significant vulnerability via partner behaviours. To stem feminization of the epidemic, health authorities should complement existing prevention interventions in high-risk populations with directed efforts towards bridging populations such as migrant workers. We identify four locally adapted HIV prevention strategies.
Rectal infections with chlamydia and gonorrhoea in women attending a multiethnic sexually transmitted diseases urban clinic
Authors: Hunte T , Alcaide M , Castro J
Published: February 2011

Sexually transmitted rectal infections with Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (GC) have been well documented in men who have sex with men (MSM). Few studies have described infections in women who engage in anal intercourse. We performed testing for rectal infections in women who reported ano-receptive intercourse at the Miami Dade Health Department Sexually Transmitted Diseases (STD) clinic and report the prevalence and characteristics of women with rectal CT or GC infections. Our results revealed a prevalence of 17.5% for rectal chlamydia and 13.4% for rectal gonorrhoea. Urine-based screening alone would have missed 6% of rectal chlamydia infections and 35% of rectal gonorrhoea infections. Anal symptoms were reported in 12.5% of women with rectal chlamydia infections. The only associated factor identified was an age less than 28 years. We conclude that rectal screening for CT and GC should be included in STD prevention strategies, especially in the younger population.
Eosinophilic oesophagitis: an unsuspected aetiology for dysphagia in an HIV-positive patient
Authors: Batog C , Psevdos G , Paniz-Mondolfi A , Srivastava S , Sharp V L
Published: February 2011

Patients with HIV/AIDS are often afflicted with oesophageal disorders. Opportunistic infections such as candidiasis, herpes simplex, cytomegalovirus, mycobacterial infections, Kaposi sarcoma or lymphoma involving the oesophagus, motility disorders and reflux oesophagitis are the usual culprits. Eosinophilic oesophagitis (EE), a recently recognized entity, is an important cause of dysphagia, food impaction and chest discomfort. We report the case of an HIV-infected man who had persistent dysphagia for six months despite treatment with proton pump inhibitor. He was diagnosed with EE after having endoscopic evaluation and biopsy of his oesophagus and was successfully treated with swallowed fluticasone. This case represents the first reported case of EE in an HIV-infected individual.
Ethnic diversity and patterns of infection of a UK HIV-positive patient population outwith major conurbations
Authors: Aiken A R A , Lever A M L
Published: February 2011

We surveyed the HIV-positive population attending a major teaching hospital sited outwith a major conurbation. Eighty-five percent of homosexually acquired infections were contracted within the UK and 91% of heterosexually acquired infections were contracted outside of the UK. A strikingly wide range of nationalities (45) and countries of origin of infection were represented within a relatively small patient population. Most patients were non-UK-born immigrants. A high proportion of illegal immigrants were identified within which there was a high proportion lost to follow-up. This degree of ethnic diversity and domiciliary instability is rarely a feature of non-HIV populations in this setting and imposes additional demands on delivery of care and health-care planning.
HIV and systemic lupus erythematosus: the clinical and diagnostic dilemmas of having dual diagnosis
Authors: Burton J , Vera J H , Kapembwa M
Published: February 2011

We present the case of a young black African woman living in the UK who presented with systemic lupus erythematosus (SLE) and HIV. The reported coexistence of HIV and SLE is unusual with fewer than 30 published cases. We discuss some of the clinical and diagnostic challenges that face clinicians when a patient presents with both conditions. In particular, we discuss the overlap in symptoms, signs and laboratory findings, and the difficulties that this may pose in terms of making a diagnosis. The implications that having a dual diagnosis may have for treating each condition are also discussed. With increased HIV testing in a variety of clinical settings there is likely to be an increase in detection of similar cases. This case emphasizes the need for careful diagnostic testing and judicious interpretation of the validity of laboratory results in order to reach an accurate diagnosis in such patients.
Prevalence and factors associated with idiopathic hypercalciuria in HIV patients on combination antiretroviral therapy
Authors: Pocaterra D , Carenzi L , Ricci E , Minisci D , Schiavini M , Gervasoni C , Meraviglia P , Bevilacqua M , Rizzardini G , Bonfanti P
Published: February 2011

Idiopathic hypercalciuria may lead to bone loss via three pathogenic mechanisms described in HIV-negative patients: intestinal hyperabsorption, kidney loss and bone hyperabsorption. We conducted a cross-sectional study in a cohort of 217 HIV-positive antiretroviral-experienced patients, identifying hypercalciuria in 67 patients: the prevalence was 30.9% (95% confidence interval 27.4–37.0). The occurrence of hypercalciuria in subjects with normal values of parathormone may indicate an absorptive form of hypercalciuria. In this sample, other bone turnover markers and T-scores were not related to the condition. The results of this study show a high prevalence of idiopathic hypercalciuria in a group of antiretroviral-experienced patients. The consequences and the exact causes of this metabolic complication are not yet known and further investigation is needed.
Minimum effective plasma concentration of efavirenz in treatment-naïve Chinese HIV-infected patients
Authors: Sun J , Chen J , Yao Y , Zhang R , Zheng Y , Liu L , Zhang L , Shen Y , Lu H
Published: February 2011

To assess the relationship between mean efavirenz (EFV) plasma concentration and clinical effect during the first 48 weeks of combination antiretroviral therapy (cART), the baseline CD4 cell count was recorded and plasma EFV concentration and CD4 cell count were measured every 12 weeks. HIV-RNA viral load was determined in the 48th week of cART. In total, 42 subjects were recruited and grouped according to their mean concentration of EFV during the study period: groups A, B and C with EFV concentrations (mean) <2 mg/L (1.8 mg/L), 2–4 mg/L (2.9 mg/L) and >4 mg/L (5.5 mg/L), respectively. The CD4 cell counts in group C increased more quickly than in groups B and A, although this was not statistically significant (211 ± 176/μL versus 151 ± 145/μL and 172 ± 105/μL, respectively; P = 0.799). Groups B and C had higher rates of HIV viral load suppression than group A ( P = 0.017). For treatment-naïve Chinese HIV-infected patients, EFV plasma concentrations above 2 mg/L appear to suppress HIV replication more effectively than concentrations below 2 mg/L.
Self-reported psychological distress associated with steroid therapy for HIV
Authors: Lyons T , Berger D , Masini B , Pinna G
Published: February 2011

Anabolic androgenic steroid (AAS) replacement therapy is standard care for patients with low testosterone, including HIV-related conditions. These medications have been associated with development of aggressiveness, anxiety disorders, and depression, but only in short-term clinical trials. We conducted an anonymous street survey at a gay and lesbian community event and a survey in a clinic-based setting to study the wider prevalence of psychiatric side-effects associated with androgenic steroids. In the street-based survey, almost half of those prescribed AAS reported psychological side-effects, most commonly aggression (29%) followed by depression (21%). In the clinic survey of mostly HIV+ male patients, changes in sex drive were the most commonly reported effect of treatment while impulsive aggression, anxiety and depression were reported at levels similar to those in the street fair survey. These findings suggest that AAS therapy may be more frequently associated with distress than has been reported in the clinical literature.
Assessment of cardiac diastolic dysfunction in HIV-infected people without cardiovascular symptoms in China
Authors: Luo L , Ye Y , Liu Z , Zuo L , Li Y , Han Y , Qiu Z , Li L , Zeng Y , Li T-S
Published: February 2011

This study assessed cardiac diastolic dysfunction (DD) in HIV-infected subjects without cardiovascular symptoms in China. Eighty-four HIV-infected patients without cardiovascular symptoms were recruited and compared with 30 HIV-negative control subjects. Cardiac DD was evaluated using echocardiography including tissue Doppler imaging. DD was detected in 47.6% of AIDS patients and 42.8% of HIV-positive patients, which was significantly higher than in HIV-negative controls. After logistic regression analysis, HIV infection was independently correlated with cardiac DD ( P < 0.05). Among HIV-positive subjects, logistic regression analysis showed that zidovudine exposure was associated with higher prevalence of DD ( P < 0.05). Asymptomatic cardiac DD was observed frequently in HIV-infected subjects. HIV infection itself and zidovudine exposure were correlated with a higher prevalence of cardiac DD.
A review of HIV postexposure prophylaxis provision at a genitourinary medicine department
Authors: Whitehead T , Fernando I
Published: February 2011

We undertook a retrospective case-note audit of all patients who presented to the Edinburgh genitourinary (GU) medicine department following a potential exposure to HIV infection during the period 1 January 2006 to 31 December 2008. Over the audit period, 81 individuals attended the department, in relation to 85 exposure events. Twenty-three (27%) exposures had occurred in a health-care occupational setting and 50 (59%) in a sexual context. Baseline HIV testing was only performed in 38 (45%) of the 85 exposures. Postexposure prophylaxis (PEP) was initiated in 65 (76%) cases: 61 (94%) received the first dose within the recommended 72 hours. In 68 (80%) of the 85 exposures, the PEP initiation decision tallied with guideline recommendations. Fifty-six of the 65 individuals started on PEP continued beyond 72 hours; 53 of them were reviewed at least once during the course of PEP and had routine blood monitoring performed. Documentation regarding adherence was poor, with only 31 having this recorded in notes. Thirty-seven (66%) individuals who continued on PEP attended for follow-up HIV testing at three months. In summary, the department performed well in some aspects of PEP provision. However, baseline HIV testing and documentation regarding adherence are unsatisfactory and we suggest recommendations to improve this.
Use of modern and traditional products to self-treat symptoms of sexually transmitted infections in South African women
Authors: Beksinska M E , Smit J , Scorgie F , Dube S , Kunene B , Martin-Hilber A , Chersich M
Published: February 2011

The objective of the study is to investigate products used by women self-treating symptoms of reproductive tract infections (RTIs), including sexually transmitted infections (STIs), and their methods of administration. A household survey using a multi-stage cluster sample design was undertaken in KwaZulu-Natal, South Africa. Women aged 18–60 years were interviewed ( n = 867) and information was collected on demographics, reproductive health and sexual behaviours. A fifth of women reported having RTI/STI symptoms (20.5%), of whom 41.9% were treating these symptoms (mostly discharge [79.1%], ulcers [6.8%] and itching [7.7%]). Only three women were using medication prescribed by a health provider, while the remainder were self-treating using traditional medicines and modern products, including antiseptics, soaps, petroleum jelly, menthol creams and alum. Products were administered in various ways. Although RTI/STI treatment is widely available and free in public health facilities, many women are still self-treating. Potential harm of products for self-treatment requires further investigation and efforts should be made to improve STI service uptake.
Jarisch–Herxheimer reaction among syphilis patients in Rio de Janeiro, Brazil
Authors: Miller W M , Gorini F , Botelho G , Moreira C , Barbosa A P , Pinto A R S B , Dias M F , Souza L M , Asensi M D , da Costa Nery J A
Published: February 2011

The Jarisch–Herxheimer reaction (JHR) is a syndrome observed after antimicrobial treatment of some infectious diseases. The syndrome has clinical characteristics of an inflammatory reaction to antibiotic treatment. A prospective study of patients with a clinical and laboratory diagnosis of syphilis was conducted at a sexually transmitted diseases clinic in Rio de Janeiro, Brazil. Patients were treated with benzathine penicillin and observed for the JHR. A total of 115 patients were included in this study. Fifty-one patients (44%) had secondary syphilis; 37 (32%), primary; 26 (23%), latent; and one (1%), tertiary syphilis. Ten patients (9%) developed the JHR. All JHRs occurred in patients with secondary and latent syphilis. No patients experienced an allergic reaction to penicillin. The JHR occurred less frequently than in previous studies. It is important that health-care professionals recognize the clinical characteristics of the JHR so that it is not misinterpreted as an allergic reaction to penicillin.
Post-coital bleeding in young women: the role of genitourinary medicine
Authors: Sonnex C , Shafi M
Published: February 2011

Recently published Department of Health (DoH) guidelines and National Health Service Cervical Screening Programme guidelines recommend referral to a genitourinary (GU) medicine or sexual health clinic as part of the management pathway for young women with post-coital bleeding (PCB). The objectives of this questionnaire study were to ascertain whether GU medicine practitioners agreed with these recommendations and to assess which skills were considered necessary regarding the diagnosis and management of cervical pathology in departments of GU medicine and sexual health and also, therefore, in training in the specialty. The majority of respondents considered it important to check for cervical infection in determining the cause of PCB, but few GU medicine practitioners now perform colposcopy and many consider themselves insufficiently trained to assess the cervix in more detail. Since the colposcope is the optimal tool for examining the anogenital tract, we suggest that colposcopy, in its broadest sense, should be reconsidered as an essential part of GU medicine training.
A semiquantitative way to measure MUAC in anaesthesia
Authors: Pollach Gregor , Mndolo Samson
Published: February 2011

As anaesthetists we have to learn to recognize malnourished children. The implications for fluid management, cardiac function, weaning and nutrition are important. Mid-upper arm circumference (MUAC) is the most useful anthropometric parameter for severely debilitated patients. We observed that the measuring tape is frequently missing or out of stock. In order to overcome this challenge we searched for an always available, easy to understand method with acceptable accuracy which is free. We conducted a study of 262 volunteers in four professional groups. In a deliberately short training session of 5–10 min we provided them with gauze bandages and asked them to measure the circumference with their own fingers, nails and interphalangeal crests. Later we showed them bandages (substitutes for upper arms) of different sizes and asked them to determine whether these were bigger or smaller than the original or the same size. Of the 1048 decisions, 91.2% were taken correctly and 97.2% were acceptable for the identification of a malnourished patient. Two hundred and thirty-five of the 262 participants (89.7%) would have been able to identify a severely malnourished child. The best subgroup recognized all children in danger and even the non-medical subgroup diagnosed 80.6%. The child who was not in need of special resources was recognized by all 262 participants (100%). Only two (0.76%) made decisions which were contradictory. A semiquantitative measurement of MUAC is possible. Our method is sufficiently exact, needs minimal training, alerts the anaesthetist and is free. We should train all professionals working in developing countries with malnourished children in the ‘one grip’ measurement of MUAC.
Human ocular angiostrongyliasis: a literature review
Authors: Diao Zongli , Wang Jing , Qi Haiyu , Li Xiaoli , Zheng Xiaoyan , Yin Chenghong
Published: February 2011

Human ocular angiostrongyliasis caused by Angiostrongylus cantonensis infection in the eye is a very rare condition. Until now, there has been no comprehensive analysis of this disease. We searched and analysed the references found on the Internet that refer to human ocular angiostrongyliasis and reviewed the aetiology, clinical manifestations, diagnosis, epidemiology and treatment of the condition. Twenty-six references were found reporting 35 patients from 10 countries that were diagnosed with human ocular angiostrongyliasis. People are usually infected by eating raw or undercooked intermediate hosts of the parasite such as snails or contaminated vegetables. The most common symptom was visual loss. Although several treatments have been used, ocular angiostrongyliasis can still result in permanent visual impairment and may even cause blindness. As the eye is the site of infection and direct visualization is possible, ocular examination is crucial for diagnosis. The therapeutic success depended on early and complete surgical removal.
Intercalation of Methylene Blue in a High-Charge Calcium Montmorillonite — An Indication of Surface Charge Determination
Authors: Li Zhaohui , Wang Chih-Jen , Jiang Wei-Teh
Published: February 2011

The suitability and applicability of using Methylene Blue (MB), a cationic dye, for cation-exchange capacity (CEC) and specific surface area (SSA) determinations has been studied extensively. Although many workers have reported satisfactory results between the CEC determined by the MB method and other methods, large discrepancies among CEC values determined by different methods are also found in the literature. The work reported herein was focused at elucidating the interlayer configuration of adsorbed/intercalated MB in SAz-1, a high-charge montmorillonite, using MB adsorption, exchangeable cation desorption, counterion (Cl−) adsorption, X-ray diffraction (XRD) and Fourier-transform infrared (FT-IR) analyses.

A complete balance between the amount of MB cation adsorbed and that of exchangeable cations desorbed at a 1:1 charge ratio for MB uptake by SAz-1 indicated that cation-exchange was the most important mechanism in this case together with supplementary hydrogen bonding. The adsorbed MB molecules associated into dimers and were orientated in the interlayer in a nearly vertical configuration, with the sulphur atom keyed onto the surface. In a vertical orientation, the MB dimer occupies a projected area of 120–130 Å2, similar to the surface area of 130 Å2 previously assumed from SSA determinations for the horizontally aligned MB molecule. Hence, it is the charge density rather than the horizontal configuration of the MB molecules that controls the MB adsorption capacity. As such, the CEC determination of swelling clays using the MB adsorption method is justified. However, SSA determination by the MB method is correct only if the charge density is less than the projected area of 120–130 Å2 for an MB dimer. This suggests that the previous assumption of the adsorption of a horizontally orientated MB molecule onto the surface of clay minerals is questionable.