bluuebunny/crossref_metadata_2025 huggingface dataset:
Telomere dysfunctional environment induces loss of quiescence and inherent impairments of hematopoietic stem cell function
Authors: Song Zhangfa , Zhang Junling , Ju Zhenyu , Rudolph K. Lenhard
Published: January 2012

Previous studies have shown that telomere dysfunction induces alteration in the systemic (circulatory) environment impairing the differentiation of hematopoietic stem cells (HSCs) but these defects can be reverted by re‐exposing HSCs to an environment with functional telomeres. In contrast, HSC intrinsic telomere dysfunction induces permanent and irreversible limitations in the repopulation capacity partially depending on the induction of checkpoints such as cell cycle arrest, differentiation, or apoptosis. It is currently unknown whether telomere dysfunctional environment can induce irreversible, cell intrinsic defects impairing the function of HSCs. Here, we analyzed the functional reserves of murine, wild‐type HSCs with intact telomeres that were transiently exposed to a telomere dysfunctional environment (late generation telomerase knockout mice) or to an environment with functional telomeres (wild‐type mice). The study shows that the telomere dysfunctional environment leads to irreversible impairments in the repopulation capacity of wild‐type HSCs. The telomere dysfunctional environment impaired the maintenance of HSC quiescent. Moreover, the study shows that alterations in the systemic (circulatory) environment rather than the bone stromal niche induce loss of stem cell quiescence and irreversible deficiencies of HSCs exposed to a telomere dysfunctional environment.
Worldwide Screening for Canine Hip Dysplasia: Where Are We Now?
Authors: Verhoeven Geert , Fortrie Ruth , Van Ryssen Bernadette , Coopman Frank
Published: January 2012

Objective

To critically review the different screening systems used for canine hip dysplasia (CHD) and their impact on the prevalence of the disease.

Study design

Critical literature review.

Methods

Literature search throughPubMed (November 1959–October 2011) and theOrthopedicFoundation forAnimals (OFA),FédérationCynologiqueInternationale (FCI),BritishVeterinaryAssociation/KennelClub (BVA/KC), andPennsylvaniaHipImprovementProgram (PennHIP) websites.

Results

TheOFA,FCI, andBVA/KCscreening methods, which use the hip‐extended radiographic projection, have had relatively minor success onCHDprevalence. These screening approaches are prone to conflicting data regarding interobserver agreement. ThePennHIPandDorsolateralSubluxation (DLS) systems, both distraction methods, have not reported on prevalence but seem to be important heritable traits in genomic screening of dysplastic dogs.

Conclusion

A shift towards genome screening yields a promising future combatingCHD, although further investigation towards fine‐mapping in the search for genes, responsible forCHD, is necessary.
Chronology of Hip Dysplasia Development in a Cohort of 48 Labrador Retrievers Followed for Life
Authors: Smith Gail K. , Lawler Dennis F. , Biery Darryl N. , Powers Michelle Y. , Shofer Frances , Gregor Thomas P. , Karbe Georga T. , McDonald‐Lynch Mischa B. , Evans Richard H. , Kealy Richard D.
Published: January 2012

Objective

To determine the chronology of radiographic signs of canine hip dysplasia (CHD), specifically joint laxity and secondary osteoarthritis (OA).

Study Design

Longitudinal cohort study.

Animals

Paired littermates, 48Labrador retrievers.

Methods

Conventional, ventrodorsal, hip‐extended (HE) radiographs were evaluated yearly forCHDaccording to the subjective criteria of the Orthopedic Foundation for Animals (OFA).PennHIPscreening was performed at 2 years of age to assess joint laxity by distraction index (DI). Histopathologic evaluation of coxofemoral joints was performed at the dogs’ natural end of life.

Results

Coxofemoral subluxation, as identified on theHEradiograph occurred by 2 years of age and not thereafter. Accuracy ofOFA‐criteria scoring was poor: 55% of dogs scored “normal” at 2 years of age became radiographically dysplastic by the end of life (45% negative predictive value,NPV); 92% of the dogs scored as normal at 2 years of age had histopathologicOAofCHD(8%NPV). TheDIpredicted all 48 dogs to be susceptible toOAofCHDand 98% had radiographic or histopathologicOAby the end of life.

Conclusion

OFA‐criteria score was profoundly influenced by environmental factors, such as diet restriction and age, reducing its value as a selection criterion.DImeasurements were not influenced by dietary treatment suggesting higher trait heritability.
Radiographic Hip Joint Phenotype of the Pembroke Welsh Corgi
Authors: Karbe Georga T. , Biery Darryl N. , Gregor Thomas P. , Giger Urs , Smith Gail K.
Published: January 2012

Objective

To investigate the radiographic hip joint phenotype of the Pembroke Welsh Corgi.

Study Design

Prospective and retrospective cross‐sectional study.

Animals

Pembroke Welsh Corgis (n = 399).

Methods

Ventrodorsal, hip‐extended radiographs were evaluated for subluxation, osteoarthritis (OA), caudolateral curvilinear osteophytes (CCO), and circumferential femoral head osteophytes (CFHO) of PennHIP evaluated Corgis. Joint laxity was measured by distraction index (DI).

Results

All Corgis had DI > 0.30 (mean, 0.66), 6.8% had OA, 18% had subluxation, 22.3% had CCO, and 74.4% had CFHO. Higher DI increased the odds for subluxation and canine hip dysplasia (CHD) but not for OA, CCO, or CFHO. The presence of CCO increased the odds for OA by 4.6 times (P= .002) and 2.2 times (P= .01) for hip dysplasia. All dogs with OA had CFHO. The presence of CFHO increased the odds for subluxation by 8.7 times (p < .001) and 8.9 times (P < .001) for hip dysplasia. Subluxation increased the odds for OA by 15.4 times (P < .001).

Conclusion

Corgis had a low frequency of conventional OA despite having hip laxity that has been shown to correlate with hip OA and hip dysplasia in large‐breed dogs. The relationship between CCO and OA was similar to published findings in nonchondrodystrophic large‐breed dogs and the CFHO was significantly associated with subluxation. Both CCO and CFHO are associated with hip dysplasia in this small chondrodystrophic breed.
Nano Total Hip Replacement in 12 Dogs
Authors: Ireifej Shadi , Marino Dominic , Loughin Catherine
Published: January 2012

Objective

To determine the short‐term clinical outcome of nano total hip replacement (NanoTHR) in dogs.

Study Design

Retrospective case series.

Animals

Dogs (n = 12).

Methods

Medical records (2009–2011) of dogs that had nano‐THR were reviewed for signalment, weight, clinical signs, side, age, prosthesis sizes, concurrent surgeries performed, complications, operative time, 3‐month postoperative pelvic radiograph results, and lameness scores.

Results

Breeds were Yorkshire Terriers (n = 6), Toy Poodles (2), with 1 each of Maltese, Pomeranian, Cavalier King Charles Spaniel, and Shih‐Tzu. Median body was 4.87 kg (range, 2.5–5.90 kg) and median age, 35.75 months (range, 12–144 months). Radiographs were taken in 4 dogs at 12 days (n = 2), 14 days (1), and 30 days (1) after surgery because of presentation for an acute grade 5 lameness. Three dogs had femoral fractures distal to the femoral implant tip and 1 dog displaced the acetabular implant medially. After revision surgery, all femoral fractures were assessed as healed with intact plate fixation. The dog with the medially displaced acetabular component responded to conservative management including strict confinement and analgesic administration. Eight dogs (58%) were assigned a grade 1 lameness and 4 dogs were grade 2 (33%) at 12‐week examination. The 3 dogs with grade 5 lameness scores found to have femoral fractures within 1 month after surgery, subsequently improved to grade 1 (n = 1) and 2 (2) 12 weeks after revision surgery. The dog with medial acetabular displacement improved to a grade 2 lameness 12 weeks after conservative management.

Conclusions

Although all 12 dogs had good‐to‐excellent outcomes, 33% experienced significant complications associated with the technique. As improvements in instrumentation and refinements in the technique are developed, NanoTHR can be considered an alternative to the femoral head and neck ostectomy (FHO) or medical management of coxofemoral disease for toy breed dogs. Further studies with a larger number of dogs and longer follow‐up times are required.
A Simple “Streak Length Method” for Quantifying and Characterizing Red Blood Cell Velocity Profiles and Blood Flow in Rat Skeletal Muscle Arterioles
Authors: AL‐KHAZRAJI BARAA K. , NOVIELLI NICOLE M. , GOLDMAN DANIEL , MEDEIROS PHILIP J. , JACKSON DWAYNE N.
Published: January 2012

Please cite this paper as: Al‐Khazraji BK, Novielli NM, Goldman D, Medeiros PJ, Jackson DN. A simple “Streak Length Method” for quantifying and characterizing red blood cell velocity profiles and blood flow in rat skeletal muscle arterioles. Microcirculation 19: 327–335, 2012.

Objectives:  To develop a valid experimental method for quantifying blood flow in continuously branching skeletal muscle arterioles, and to derive an empirical relationship between velocity ratio (VMax/VMean) and arteriolar diameter.

Methods:  We evaluated arteriolar trees using IVVM of rat gluteus maximus muscle and developed a method to acquire single fluorescent‐labeled RBC velocities across arteriolar lumens to create velocity profiles. These data were used to calculate the blood flow for 37 vessel segments (diameters: 21–115 μm).

Results:  Mass balance at arteriolar bifurcations had 0.6 ± 3.2% error. Velocity ratios ranged from 1.35 to 1.98 and were positively correlated with diameter (p < 0.0001), and VRBC profiles were blunted with decreasing diameter.

Conclusions:  We present a means for quantifying blood flow in continuously branching skeletal muscle arterioles. Further, we provide an equation for calculating velocity ratios based on arteriolar diameter, which may be used by others for blood flow calculations.
Spotlight Issue: MicroRNAs in the Microcirculation—From Cellular Mechanisms to Clinical Markers
Authors: SIOW RICHARD C.M. , CLOUGH GERALDINE F.
Published: January 2012

Please cite this paper as: Siow RCM, Clough GF. Spotlight Issue: MicroRNAs in the microcirculation—from cellular mechanisms to clinical markers. Microcirculation19: 193–195, 2012.

This spotlight issue of Microcirculation contains four state‐of‐the‐art review articles on the role of microRNAs (miRNAs), a class of endogenous, highly conserved, small, non‐coding RNAs that regulate gene expression at the post transcriptional level, and can act as key regulators of cellular mechanisms within the microcirculation. The expert reviews address issues, such as the role of miRNAs in determining endothelial cell differentiation and lineage commitment, the physiological role of miRNAs as critical modulators of endothelial cell proliferation, apoptosis and in angiogenesis, and their aberrant expression in different vascular disorders. The reviews also explore the prognostic value of miRNAs in cardiovascular disease and how they may serve both as a therapeutic target and clinical biomarker in the future. This cutting edge edition of the journal Microcirculation highlights the progress that has been made in this new and challenging research area.
Up‐regulation of BMP‐2 antagonizes TGF‐β1/ROCK‐enhanced cardiac fibrotic signalling through activation of Smurf1/Smad6 complex
Authors: Wang Shijun , Sun Aijun , Li Lei , Zhao Gang , Jia Jianguo , Wang Keqiang , Ge Junbo , Zou Yunzeng
Published: January 2012

Rho‐associated kinase (ROCK) plays a critical role in pressure overload‐induced left ventricular remodelling. However, the underlying mechanism remains unclear. Here, we reported that TGF‐β1‐induced ROCK elevation suppressed BMP‐2 level and strengthened fibrotic response. Exogenous BMP‐2 supply effectively attenuated TGF‐β1 signalling pathway through Smad6‐Smurf‐1 complex activation. In vitro cultured cardiomyocytes, mechanical stretch up‐regulated cardiac TGF‐β1, TGF‐β1‐dependent ROCK and down‐regulated BMP‐2, but BMP‐2 level could be reversed through blocking TGF‐β1 receptor by SB‐431542 or inhibition of ROCK by Y‐27632. TGF‐β1 could also activate ROCK and suppress endogenous BMP‐2 level in a dose‐dependent manner. Knock‐down BMP‐2 enhanced TGF‐β1‐mediated PKC‐δ and Smad3 signalling cascades. In contrast, treatment with Y‐27632 or SB‐431542, respectively suppressed ROCK‐dependent PKC‐δ and Smad3 activation, but BMP‐2 was only up‐regulated by Y‐27632. In addition, BMP‐2 silencing abolished the effect of Y‐27632, but not SB‐431542 on suppression of TGF‐β1 pathway. Further experiments showed that Smad6 Smurf1 interaction were required for BMP‐2‐evoked antagonizing effects. Smad6 overexpression attenuated TGF‐β1‐induced activation of PKC‐δ and Smad3, promoted TGF‐β RI degradation in BMP‐2 knock‐down cardiomyocytes, and could be abolished after knocking‐down Smurf‐1, in which Smad6/Smurf1 complex formation was critically involved. In vivo data showed that pressure overload‐induced collagen deposition was attenuated, cardiac function was improved and TGF‐β1‐dependent activation of PKC‐δ and Smad3 was reduced after 2 weeks treatment with rhBMP‐2(0.5 mg/kg) or Y‐27632 (10 mg/kg) in mice that underwent surgical transverse aortic constriction. In conclusion, we propose that BMP‐2, as a novel fibrosis antagonizing cytokine, may have potential beneficial effect in attenuating pressure overload‐induced cardiac fibrosis.
Immortalized sebocytes can spontaneously differentiate into a sebaceous‐like phenotype when cultured as a 3D epithelium
Authors: Barrault Christine , Dichamp Isabelle , Garnier Julien , Pedretti Nathalie , Juchaux Franck , Deguercy Alain , Agius Gérard , Bernard François‐Xavier
Published: January 2012

Abstract:  Sebocytes originate from the same lineage as keratinocytes, and both cell types may have similarities in terms of growth and differentiation. We were interested in studying the behaviour of human sebocytes when cultured in conditions validated for epidermal reconstruction. For this purpose, we established a HPV16‐E6/7‐immortalized human sebocyte cell line (SEBO662) growing in keratinocyte defined media. Postconfluent SEBO662 cells in monolayers express the early sebocyte marker, cytokeratin 7 (K7), do not express Epithelia Membrane Antigen (EMA) and do not exhibit strong lipogenic activity. However, when placed at the air–liquid interface, SEBO662 multilayers spontaneously differentiate into a sebaceous‐like structure as shown by the strong polarized expression of the late sebaceous marker EMA, the overexpression of some lipogenic markers and lipid production on the upper side of the epithelium. This work highlights the value of simple 3D models for exhibiting spontaneous differentiation and polarization.
Diabetes screening at the periodontal visit: patient and provider experiences with two screening approaches
Authors: Rosedale MT , Strauss SM
Published: January 2012

To cite this article:   Int J Dent Hygiene10, 2012; 250–258  DOI: 10.1111/j.1601‐5037.2011.00542.x

Rosedale MT, Strauss SM. Diabetes screening at the periodontal visit: patient and provider experiences with two screening approaches.

Abstract:  Objectives: This study examined patient and dental provider experiences during the periodontal visit of diabetes screening approaches involving the collection of gingival crevicular blood (GCB) and finger stick blood (FSB) for haemoglobin A1c (HbA1c) testing. Methods: At a large, urban, US periodontics and implant clinic, FSB samples from 120 patients and GCB samples from 102 of these patients were collected on special blood collection cards and sent to a laboratory for HbA1c testing, with test results sent to the patients from the laboratory. Quantitative and qualitative data from patients and qualitative data from providers were collected and analysed. Results: Quantitative and qualitative data support the feasibility and acceptability of the approaches described. Themes that arose from the interviews with providers and patients include ‘a good chance to check’, ‘patient choice’, ‘FSB versus GCB testing’ and ‘a new way of interacting and viewing the dental visit’. Conclusions: Periodontal patients and dental providers believe that the dental visit is an opportune site for diabetes screening and generally prefer GCB to FSB collection. HbA1c testing is well tolerated, convenient and acceptable to patients, and GCB testing reduces time and liability obstacles for dental providers to conduct diabetes screening.
Porphyromonas gingivalis and its lipopolysaccharide differentially regulate the expression of cathepsin B in endothelial cells
Authors: Huck O. , Elkaim R. , Davideau J.L. , Tenenbaum H.
Published: January 2012

Porphyromonas gingivalis infection and cathepsins protease upregulation are independently implicated in atherosclerosis worsening. In this study, we evaluated the effects of P. gingivalis infection and P. gingivalis ‐purified lipopolysaccharide (Pg‐LPS) stimulation on the expression of cathepsin B (CATB) in endothelial cells (ECs). Analysis of the enzymatic activity and expression of CATB were investigated at the messenger RNA, protein and protein‐phosphorylation levels. Effects of Toll‐like receptors 2 and 4 blocking on CATB activity were also analysed. Our results showed that P. gingivalis and Pg‐LPS significantly increased the activity of CATB but with different kinetics. The peak of CATB activity was observed 3 h after P. gingivalis infection but it appeared 48 h after Pg‐LPS stimulation. The increase of CATB activity was related to its rapid tyrosine‐dephosphorylation during P. gingivalis infection, whereas the levels of CATB messenger RNAs and proteins did not vary after P. gingivalis infection or Pg‐LPS stimulation. Inhibition of Toll‐like‐receptors 2 and 4 differentially decreased P. gingivalis and Pg‐LPS CATB activations. These results showed for the first time that P. gingivalis infection rapidly affects ECs and modulates CATB activity, whereas Pg‐LPS effects appear to be delayed. This study suggests that direct infection of ECs by P. gingivalis may worsen atherosclerotic plaque formation via activation of the CATB pathway.
Chronic activation of endogenous angiotensin‐converting enzyme 2 protects diabetic rats from cardiovascular autonomic dysfunction
Authors: Murça Tatiane M. , Almeida Tatiane C. S. , Raizada Mohan K. , Ferreira Anderson J.
Published: January 2012

In this study, we evaluated whether the activation of endogenous angiotensin‐converting enzyme 2 (ACE2) would improve the cardiovascular autonomic dysfunction of diabetic rats. Ten days after induction of type 1 diabetes (streptozotocin, 50 mg kg−1i.v.), the rats were treated orally with 1‐[(2‐dimethylamino)ethylamino]‐4‐(hydroxymethyl)‐7‐[(4‐methylphenyl) sulfonyl oxy]‐9H‐xanthene‐9‐one (XNT), a newly discovered ACE2 activator (1 mg kg−1 day−1), or saline (equivalent volume) for 30 days. Autonomic cardiovascular parameters were evaluated in conscious animals, and an isolated heart preparation was used to analyse cardiac function. Diabetes induced a significant decrease in the baroreflex bradycardia sensitivity, as well as in the chemoreflex chronotropic response and parasympathetic tone. The XNT treatment improved these parameters by ∼76% [0.82 ± 0.09 versus 1.44 ± 0.17 Ratio between changes in pulse interval and changes in mean arterial pressure (ΔPI/ΔmmHg)], ∼85% (−57 ± 9 versus−105 ± 10 beats min‐1) and ∼205% (22 ± 2 versus 66 ± 12 beats min‐1), respectively. Also, XNT administration enhanced the bradycardia induced by the chemoreflex activation by ∼74% in non‐diabetic animals (−98 ± 16 versus−170 ± 9 Δbeats min‐1). No significant changes were observed in the mean arterial pressure, baroreflex tachycardia sensitivity, chemoreflex pressor response and sympathetic tone among any of the groups. Furthermore, chronic XNT treatment ameliorated the cardiac function of diabetic animals. However, the coronary vasoconstriction observed in diabetic rats was unchanged by ACE2 activation. These findings indicate that XNT protects against the autonomic and cardiac dysfunction induced by diabetes. Thus, our results provide evidence for the viability and effectiveness of oral administration of an ACE2 activator for the treatment of the cardiovascular autonomic dysfunction caused by diabetes.
Testing the plasticity of insulin secretion and β‐cell function in vivo: responses to chronic hyperglycaemia in the sheep
Authors: Gatford Kathryn L. , De Blasio Miles J. , How Tasma A. , Harland M. Lyn , Summers‐Pearce Brooke L. , Owens Julie A.
Published: January 2012

Plasticity of insulin secretion is essential to maintain the action of insulin during insulin resistance and to prevent diabetes. Investigation of the plasticity of insulin secretion and its regulation is challenging, and the objective of this study was to develop a novel large‐animal‐based model. The effect of chronic moderate hyperglycaemia on the plasticity of insulin secretion, β‐cell mass and function was determined in sheep. Adolescent sheep (120 days old) were infused with 25% glucose for 16 days to increase blood glucose by 50% (n= 10), and control animals (n= 9) were infused with saline. Glucose‐ and arginine‐stimulated insulin secretion, insulin sensitivity and glucose effectiveness were measured in vivo before and during treatment (days 10–14), and β‐cell mass was measured at the end of treatment. Hyperglycaemia increased blood glucose (+53%) and plasma insulin (+403%; each P < 0.003) and did not alter whole‐body insulin sensitivity. Hyperglycaemia increased glucose‐stimulated insulin secretion (particularly second phase; five‐fold) and arginine‐stimulated insulin secretion (particularly first phase; four‐fold). Hyperglycaemia reduced β‐cell mass (∼50%, P= 0.038) and increased glucose‐ and arginine‐stimulated insulin secretion relative to β‐cell mass five‐fold (P= 0.060) and 20‐fold (P= 0.007), respectively. Chronic hyperglycaemia therefore induces marked adaptation and upregulation of glucose‐ and arginine‐stimulated insulin secretion by enhancing β‐cell function rather than increasing β‐cell mass in the sheep, consistent with long‐term adaptations seen in humans. This marked plasticity of insulin secretion in response to moderate hyperglycaemia provides a novel model for the investigation of factors affecting its capacity and underlying determinants.
Survival and Virulence of Salmonella enterica Serovar Enteritidis Filaments Induced by Reduced Water Activity
Authors: Stackhouse Robert R. , Faith Nancy G. , Kaspar Charles W. , Czuprynski Charles J. , Wong Amy C. Lee
Published: January 2012

Salmonella enterica
serovar Enteritidis strain E40 filaments were developed under conditions of a reduced water activity (a
w
) of 0.95 in tryptic soy broth (TSB) or tryptic soy agar (TSA) supplemented with 8% or 7% NaCl, respectively. Filament formation was accompanied by an increase of biomass without an increase in CFU and was affected by incubation temperature and the physical milieu. The greatest amount of filaments was recovered from TSA with 7% NaCl and incubation at 30°C. Within 2 h of transfer to fresh TSB, filaments started to septate into normal-sized cells, resulting in a rapid increase in CFU.
S
. Enteritidis E40 filaments were not more tolerant of low- or high-temperature stresses than nonfilamented control cells. However, there was greater survival of filaments in 10% bile salts after 24 to 48 h of incubation, during pH 2.0 acid challenge for 10 min, and under desiccation on stainless steel surfaces at 25°C and 75.5% relative humidity for 7 days.
S
. Enteritidis E40 filaments invaded and multiplied within Caco-2 human intestinal epithelial cells to a similar degree as control cells when a comparable CFU of filaments and control cells was used.
S
. Enteritidis E40 filaments established a successful infection in mice via intragastric inoculation. The filaments colonized the gastrointestinal tract and disseminated to the spleen and liver at levels comparable to those attained by control cells, even when animals were inoculated with 10- to 100-fold fewer CFU. To our knowledge this is the first demonstration of virulence of stress-induced
Salmonella
filaments
in vitro
and
in vivo
. Formation of filaments by
Salmonella
in food products and food processing environments is significant to food safety, because detection and quantitation of the pathogen may be compromised. The finding that these filaments are virulent further enhances their potential public health impact.
Dry Collection and Culture Methods for Recovery of Methicillin-Susceptible and Methicillin-Resistant Staphylococcus aureus Strains from Indoor Home Environments
Authors: Davis Meghan F. , Baron Patrick , Price Lance B. , Williams D'Ann L. , Jeyaseelan Selvi , Hambleton Ian R. , Diette Gregory B. , Breysse Patrick N. , McCormack Meredith C.
Published: January 2012

Staphylococcus aureus
in home environments may serve as a reservoir for human colonization, making sampling of indoor surfaces relevant to exposure assessment. Using laboratory experiments and application to homes of asthmatic children in Barbados, we characterize microbiological methods adapted for settings with transportation delays between sampling and initiation of culture.
Identification of Cellulose-Responsive Bacterial and Fungal Communities in Geographically and Edaphically Different Soils by Using Stable Isotope Probing
Authors: Eichorst Stephanie A. , Kuske Cheryl R.
Published: January 2012

Many bacteria and fungi are known to degrade cellulose in culture, but their combined response to cellulose in different soils is unknown. Replicate soil microcosms amended with [13C]cellulose were used to identify bacterial and fungal communities responsive to cellulose in five geographically and edaphically different soils. The diversity and composition of the cellulose-responsive communities were assessed by DNA-stable isotope probing combined with Sanger sequencing of small-subunit and large-subunit rRNA genes for the bacterial and fungal communities, respectively. In each soil, the13C-enriched, cellulose-responsive communities were of distinct composition compared to the original soil community or12C-nonenriched communities. The composition of cellulose-responsive taxa, as identified by sequence operational taxonomic unit (OTU) similarity, differed in each soil. When OTUs were grouped at the bacterial order level, we found that members of theBurkholderiales,Caulobacteriales,Rhizobiales,Sphingobacteriales,Xanthomonadales, and the subdivision 1Acidobacteriawere prevalent in the13C-enriched DNA in at least three of the soils. The cellulose-responsive fungi were identified as members of theTrichocladium,Chaetomium,Dactylaria, andArthrobotrysgenera, along with two novelAscomycotaclusters, unique to one soil. Although similarities were identified in higher-level taxa among some soils, the composition of cellulose-responsive bacteria and fungi was generally unique to a certain soil type, suggesting a strong potential influence of multiple edaphic factors in shaping the community.
Dynamic Localization of Trypanosoma brucei Mitochondrial DNA Polymerase ID
Authors: Concepción-Acevedo Jeniffer , Luo Juemin , Klingbeil Michele M.
Published: January 2012

Trypanosomes contain a unique form of mitochondrial DNA called kinetoplast DNA (kDNA) that is a catenated network composed of minicircles and maxicircles. Several proteins are essential for network replication, and most of these localize to the antipodal sites or the kinetoflagellar zone. Essential components for kDNA synthesis include three mitochondrial DNA polymerases TbPOLIB, TbPOLIC, and TbPOLID). In contrast to other kDNA replication proteins, TbPOLID was previously reported to localize throughout the mitochondrial matrix. This spatial distribution suggests that TbPOLID requires redistribution to engage in kDNA replication. Here, we characterize the subcellular distribution of TbPOLID with respect to theTrypanosoma bruceicell cycle using immunofluorescence microscopy. Our analyses demonstrate that in addition to the previously reported matrix localization, TbPOLID was detected as discrete foci near the kDNA. TbPOLID foci colocalized with replicating minicircles at antipodal sites in a specific subset of the cells during stages II and III of kDNA replication. Additionally, the TbPOLID foci were stable following the inhibition of protein synthesis, detergent extraction, and DNase treatment. Taken together, these data demonstrate that TbPOLID has a dynamic localization that allows it to be spatially and temporally available to perform its role in kDNA replication.
Interactions of Sen1, Nrd1, and Nab3 with Multiple Phosphorylated Forms of the Rpb1 C-Terminal Domain in Saccharomyces cerevisiae
Authors: Chinchilla Karen , Rodriguez-Molina Juan B. , Ursic Doris , Finkel Jonathan S. , Ansari Aseem Z. , Culbertson Michael R.
Published: January 2012

The
Saccharomyces cerevisiae SEN1
gene codes for a nuclear, ATP-dependent helicase which is embedded in a complex network of protein-protein interactions. Pleiotropic phenotypes of mutations in
SEN1
suggest that Sen1 functions in many nuclear processes, including transcription termination, DNA repair, and RNA processing. Sen1, along with termination factors Nrd1 and Nab3, is required for the termination of noncoding RNA transcripts, but Sen1 is associated during transcription with coding and noncoding genes. Sen1 and Nrd1 both interact directly with Nab3, as well as with the C-terminal domain (CTD) of Rpb1, the largest subunit of RNA polymerase II. It has been proposed that Sen1, Nab3, and Nrd1 form a complex that associates with Rpb1 through an interaction between Nrd1 and the Ser
5
-phosphorylated (Ser
5
-P) CTD. To further study the relationship between the termination factors and Rpb1, we used two-hybrid analysis and immunoprecipitation to characterize
sen1-R302W
, a mutation that impairs an interaction between Sen1 and the Ser
2
-phosphorylated CTD. Chromatin immunoprecipitation indicates that the impairment of the interaction between Sen1 and Ser
2
-P causes the reduced occupancy of mutant Sen1 across the entire length of noncoding genes. For protein-coding genes, mutant Sen1 occupancy is reduced early and late in transcription but is similar to that of the wild type across most of the coding region. The combined data suggest a handoff model in which proteins differentially transfer from the Ser
5
- to the Ser
2
-phosphorylated CTD to promote the termination of noncoding transcripts or other cotranscriptional events for protein-coding genes.
Connecting Environment and Genome Plasticity in the Characterization of Transformation-Induced SOS Regulation and Carbon Catabolite Control of the Vibrio cholerae Integron Integrase
Authors: Baharoglu Zeynep , Krin Evelyne , Mazel Didier
Published: January 2012

The human pathogen
Vibrio cholerae
carries a chromosomal superintegron (SI). The SI contains an array of hundreds of gene cassettes organized in tandem which are stable under conditions when no particular stress is applied to bacteria (such as during laboratory growth). Rearrangements of these cassettes are catalyzed by the activity of the associated integron integrase. Understanding the regulation of integrase expression is pivotal to fully comprehending the role played by this genetic reservoir for bacterial adaptation and its connection with the development of antibiotic resistance. Our previous work established that the integrase is regulated by the bacterial SOS response and that it is induced during bacterial conjugation. Here, we show that transformation, another horizontal gene transfer (HGT) mechanism, also triggers integrase expression through SOS induction, underlining the importance of HGT in genome plasticity. Moreover, we report a new cyclic AMP (cAMP)-cAMP receptor protein (CRP)-dependent regulation mechanism of the integrase, highlighting the influence of the extracellular environment on chromosomal gene content. Altogether, our data suggest an interplay between different stress responses and regulatory pathways for the modulation of the recombinase expression, thus showing how the SI remodeling mechanism is merged into bacterial physiology.
A Clp/Hsp100 Chaperone Functions in Myxococcus xanthus Sporulation and Self-Organization
Authors: Yan Jinyuan , Garza Anthony G. , Bradley Michael D. , Welch Roy D.
Published: January 2012

The Clp/Hsp100 proteins are chaperones that play a role in protein degradation and reactivation. In bacteria, they exhibit a high degree of pleiotropy, affecting both individual and multicellular phenotypes. In this article, we present the first characterization of a Clp/Hsp100 homolog in
Myxococcus xanthus
(MXAN_4832 gene locus). Deletion of MXAN_4832 causes defects in both swarming and aggregation related to cell motility and the production of fibrils, which are an important component of the extracellular matrix of a swarm. The deletion also affects the formation of myxospores during development, causing them to become sensitive to heat. The protein product of MXAN_4832 can act as a chaperone
in vitro
, providing biochemical evidence in support of our hypothesis that MXAN_4832 is a functional Clp/Hsp100 homolog. There are a total of 12 Clp/Hsp100 homologs in
M. xanthus
, including MXAN_4832, and, based on its mutational and biochemical characterization, they may well represent an important group.
Good Medical Practiceor CanMEDS for education?
Authors: Gray Trevor , Grant Janet
Published: January 2012

Background

The medical regulator in the UK, the General Medical Council, requires curricula and assessments for postgraduate training to be blueprinted to its regulatory statement,Good Medical Practice. A similar document,Tomorrow's Doctors (2009), covers undergraduate education and training.Good Medical Practice, originally designed to regulate medical practice, is not optimally worded as an educational document. The Royal College of Physicians and Surgeons of Canada's physician competency framework known as CanMEDS is designed with education more centrally in mind.

Methods

The wordings ofGood Medical PracticeandTomorrow's Doctors (2009)were compared with CanMEDS using ‘word clouds’, a textual analysis tool which provides a display of word frequency, revealing the emphasis in the wording of documents.

Results

Good Medical Practiceplaces much greater emphasis on the regulatory rather than the educational aspects of medical practice when compared with CanMEDS and is therefore less suitable for blueprinting curricula, especially in disciplines with high science content such as pathology.

Conclusions

Good Medical Practiceis less suitable for an educational role and the General Medical Council should consider developing a more specific educational document around these principles.
Trends in device-assisted aneurysm treatment at a single high-volume tertiary care center
Authors: Spiotta Alejandro M , Hui Ferdinand K , Moskowitz Shaye I
Published: January 2012

Introduction

Device developments and evolution in technique over the past decade make the treatment of aneurysms which were previously considered poor candidates for coiling more feasible. The authors describe their experience treating aneurysms at a single high-volume tertiary care center, focusing particularly on the use of adjunctive devices.

Methods

A retrospective review was undertaken of all the aneurysms treated at the Cleveland Clinic between 2003 and 2010.

Results

A total of 1455 aneurysms were treated (45% subarachnoid hemorrhage). In 2003, aneurysms were treated equally with clipping (49.6%) and coiling (50.4%). Over the 8-year period reviewed there was a decline in the percentage of aneurysms treated surgically. By 2010, 25.5% of aneurysms were treated surgically and 74.5% by endovascular coiling. Among aneurysms that were coiled there was an increase in the cases treated with adjuncts including balloon remodeling and stents. The most dramatic increase in the relative proportion of a single method was the more widespread use of the combined ‘balloon stent’ technique. Initially used in 12% of stent-assisted cases, it is currently employed in 35.4% of cases.

Conclusions

Significant changes in practice trends for aneurysm treatment have been observed at a single high-volume tertiary care center over the past decade. Although these changes are multifactorial, they are explained in part by institutional comfort level with the adoption of adjunctive techniques, with a growing number of aneurysms treated with balloon remodeling and the ‘balloon stent’ technique.
Injection drug use, sexual risk, violence and STI/HIV among Moscow female sex workers
Authors: Decker Michele R , Wirtz Andrea L , Baral Stefan D , Peryshkina Alena , Mogilnyi Vladmir , Weber Rachel A , Stachowiak Julie , Go Vivian , Beyrer Chris
Published: January 2012

Background/objectives

The HIV prevalence in Eastern Europe and Central Asia continues to increase. While injection drug use (IDU) is leading factor, heterosexual transmission is on the rise. Little is known about female sex workers (FSWs) in the region despite the central role of commercial sex in heterosexual sexually transmitted infection (STI)/HIV transmission globally. The authors evaluated the prevalence of STI/HIV among Moscow-based FSWs and potential risk factors including IDU, sexual risks and violence victimisation.

Methods

Moscow-based FSWs (n=147) completed a clinic-based survey and STI/HIV testing over an 8-month period in 2005.

Results

HIV prevalence was 4.8%, and 31.3% were infected with at least one STI including HIV. Sexual behaviours significantly associated with STI/HIV included anal sex (adjusted odds ratio (AOR) 3.48), high client volume (three or more clients daily, AOR 2.71), recentsubbotnik(sex demanded by police; AOR 2.50) and regularly being presented with more clients than initially agreed to (AOR 2.45). Past year experiences of physical violence from clients and threats of violence from pimps were associated with STI/HIV (AOR 3.14 and AOR 3.65, respectively). IDU was not significantly associated with STI/HIV. Anal sex and high client volume partially mediated the associations of abuse with STI/HIV.

Conclusions

Findings illustrate substantial potential for heterosexual STI/HIV transmission in a setting better known for IDU-related risk. Many of the STI/HIV risks observed are not modifiable by FSWs alone. STI/HIV prevention efforts for this vulnerable population will benefit from reducing coercion and abuse perpetrated by pimps and clients.
Why do condoms break? A study of female sex workers in Bangalore, south India
Authors: Bradley Janet , Rajaram S P , Moses Stephen , Boily Marie Claude , Ramesh B M , Isac Shajy , Lobo Anil , Gowda G Chandrashekhar , Pushpalatha R , Gurav Kaveri , Kumar Sunil , Washington Reynold , Pickles Michael , Alary Michel
Published: January 2012

Objectives

The purpose of the study was to obtain a better understanding of the relative importance of personal factors, male partner factors and situational factors, in determining condom breakage in a population of female sex workers (FSWs) in Bangalore.

Methods

The authors conducted a cross-sectional study that included a face-to-face interview and condom application test, with 291 randomly selected FSWs in Bangalore, India, in early 2011.

Results

Ninety-seven per cent of respondents noted condom use at last sex; 34% reported a condom breakage in the last month. Combining individual, situational and partner aspects of condom breakage into one logistic regression model and also controlling for client load, the authors found that partner and situational factors were dominant since the only significant predictors of condom breakage included being a paying client (adjusted odds ratio 4.61, 95% CI 1.20 to 17.58, p=0.025), the condom being too small for the penis (adjusted odds ratio 2.29, 95% CI 0.97 to 5.40, p=0.056) or too big for the penis (adjusted odds ratio 4.29, 95% CI 1.43 to 12.80, p=0.009) and rough sex (adjusted odds ratio 6.39 CI 3.55 to 11.52, p<0.001).

Conclusions

Condom use among Bangalore FSWs is now very high. However, condom breakage is still a not uncommon event and puts women and their clients at unnecessary risk of infection. It may be difficult to eliminate the problem completely, but every effort should be made to discuss with sex workers the findings of this survey that point to possible personal markers of risk seen in the univariate analysis and to highlight the importance of avoiding rough sex and of ensuring the condom fits the client.
Pressure overload-dependent membrane type 1-matrix metalloproteinase induction: relationship to LV remodeling and fibrosis
Authors: Zile Michael R. , Baicu Catalin F. , Stroud Robert E. , Van Laer An , Arroyo Jazmine , Mukherjee Rupak , Jones Jeffrey A. , Spinale Francis G.
Published: January 2012

Increased myocardial extracellular matrix collagen represents an important structural milestone during the development of left ventricular (LV) pressure overload (PO); however, the proteolytic pathways that contribute to this process are not fully understood. This study tested the hypothesis that membrane type 1-matrix metalloproteinase (MT1-MMP) is directly induced at the transcriptional level in vivo during PO and is related to changes in LV collagen content. PO was induced in vivo by transverse aortic constriction in transgenic mice containing the full length human MT1-MMP promoter region ligated to luciferase (MT1-MMP Prom mice). MT1-MMP promoter activation (luciferase expression), expression, and activity; collagen volume fraction (CVF); and left atrial dimension were measured at 1 ( n = 8), 2 ( n = 12), and 4 ( n = 17) wk following PO. Non-PO mice ( n = 10) served as controls. Luciferase expression increased by fivefold at 1 wk, fell at 2 wk, and increased again by ninefold at 4 wk of PO ( P < 0.05). MT1-MMP expression and activity increased at 1 wk, fell at 2 wk, and increased again at 4 wk after PO. CVF increased at 1 wk, remained unchanged at 2 wk, and increased by threefold at 4 wk of PO ( P < 0.05). There was a strong positive correlation between CVF and MT1-MMP activity ( r = 0.80, P < 0.05). Left atrial dimension remained unchanged at 1 and 2 wk but increased by 25% at 4 wk of PO. When a mechanical load was applied in vitro to LV papillary muscles isolated from MT1-MMP Prom mice, increased load caused MT1-MMP promoter activation to increase by twofold and MT1-MMP expression to increase by fivefold ( P < 0.05). These findings challenge the canonical belief that PO suppresses overall matrix proteolytic activity, but rather supports the concept that certain proteases, such as MT1-MMP, play a pivotal role in PO-induced matrix remodeling and fibrosis.
The onset of left ventricular diastolic dysfunction in SHR rats is not related to hypertrophy or hypertension
Authors: Dupont S. , Maizel J. , Mentaverri R. , Chillon J.-M. , Six I. , Giummelly P. , Brazier M. , Choukroun G. , Tribouilloy C. , Massy Z. A. , Slama M.
Published: January 2012

Left ventricular (LV) diastolic dysfunction, particularly relaxation abnormalities, are known to be associated with the development of LV hypertrophy (LVH). Preliminary human and animal studies suggested that early LV diastolic dysfunction may be revealed independently of LVH. However, whether LV diastolic dysfunction is compromised before the onset of hypertension and LVH remains unknown. We therefore evaluated LV diastolic function in spontaneously hypertensive rats (SHR) at different ages and tested whether LV diastolic dysfunction is associated with abnormal intracellular calcium homeostasis. LV systolic and diastolic functions were evaluated by invasive and echocardiographic methods in 3-week-old (without hypertension) and 5-week-old (with hypertension) SHR and Wistar-Kyoto control rats. Basal intracytoplasmic calcium and sarcoplasmic reticulum (SR) Ca2+ contents were measured in cardiomyocytes using fura-2 AM. Sarco(endo)plasmic Ca2+-ATPase isoform 2a (SERCA 2a) and phospholamban (PLB) expressions were quantified by Western blot and quantitative RT-PCR techniques. LV relaxation dysfunction was observed in 3-week-old SHR rats before onset of hypertension and LVH. An increase in basal intracytoplasmic Ca2+ and a decrease in SR Ca2+ release were demonstrated in SHR. Decreased expression of SERCA 2a and Ser16 PLB (p16-PLB) protein levels was also observed in SHR rats, whereas mRNA expression was not decreased. For the first time, we have shown that LV myocardial dysfunction precedes hypertension in 3-week-old SHR rats. This LV myocardial dysfunction was associated with high diastolic [Ca2+]i possibly due to decreased SERCA 2a and p16-PLB protein levels. Diastolic dysfunction may be a potential predictive marker of arterial hypertension in genetic hypertension syndromes.
Sympathetic activation and nitric oxide function in early hypertension
Authors: Gamboa Alfredo , Okamoto Luis E. , Diedrich André , Choi Leena , Robertson David , Farley Ginnie , Paranjape Sachin , Biaggioni Italo
Published: January 2012

The purpose of this study was to determine if tonic restrain of blood pressure by nitric oxide (NO) is impaired early in the development of hypertension. Impaired NO function is thought to contribute to hypertension, but it is not clear if this is explained by direct effects of NO on vascular tone or indirect modulation of sympathetic activity. We determined the blood pressure effect of NO synthase inhibition with Nω-monomethyl-l-arginine (l-NMMA) during autonomic blockade with trimethaphan to eliminate baroreflex buffering and NO modulation of autonomic tone. In this setting, impaired NO modulation of vascular tone would be reflected as a blunted pressor response to l-NMMA. We enrolled a total of 66 subjects (39 ± 1.3 yr old, 30 females), 20 normotensives, 20 prehypertensives (blood pressure between 120/80 and 140/90 mmHg), 17 hypertensives, and 9 smokers (included as “positive” controls of impaired NO function). Trimethaphan normalized blood pressure in hypertensives, suggesting increased sympathetic tone contributing to hypertension. In contrast, l-NMMA produced similar increases in systolic blood pressure in normal, prehypertensive, and hypertensive subjects (31 ± 2, 32 ± 2, and 30 ± 3 mmHg, respectively), whereas the response of smokers was blunted (16 ± 5 mmHg, P = 0.012). Our results suggest that sympathetic activity plays a role in hypertension. NO tonically restrains blood pressure by ∼30 mmHg, but we found no evidence of impaired modulation by NO of vascular tone contributing to the early development of hypertension. If NO deficiency contributes to hypertension, it is likely to be through its modulation of the autonomic nervous system, which was excluded in this study.