Improved Detection of Biofilm-formative Bacteria by Vortexing and Sonication: A Pilot Study

Bacteria such as staphylococci commonly encountered in orthopaedic infections form biofilms and adhere to bone implants and cements. Various methods to disrupt the biofilm and enhance bacterial detection have been reported. We will describe the effectiveness of vortexing and sonication to improve the detection of biofilm-formative bacteria from polymethylmethacrylate by conventional quantitative bacterial culture and real-time quantitative PCR. We used a single biofilm-formative Staphylococcus aureus strain and 20 polymethylmethacrylate coupons as an in vitro biofilm model; four coupons were used for each of two control groups or three experimental sonication times (1, 5, and 30 minutes). Vortexing the cement without sonication increased the yield of adherent bacteria to a considerable extent. The combination of vortexing and sonication further enhanced the yield regardless of the duration of sonication. Quantitative conventional cultures correlated with quantitative PCR assay. The combination of vortexing and sonication to disrupt the bacterial biofilm followed by quantitative PCR and/or culture seems to be a sensitive method for detecting bacteria adherent to bone cement. Each author certifies that he or she has no commercial associations (eg, consultancies, stock ownership, equity interest, patent/licensing arrangements, etc) that might pose a conflict of interest in connection with the submitted article.     

Object properties and cognitive load in the formation of associative memory during precision lifting

When we manipulate familiar objects in our daily life, our grip force anticipates the physical demands right from the moment of contact with the object, indicating the existence of a memory for relevant object properties. This study explores the formation and consolidation of the memory processes that associate either familiar (size) or arbitrary object features (color) with object weight. In the general task, participants repetitively lifted two differently weighted objects (580 and 280 g) in a pseudo-random order. Forty young healthy adults participated in this study and were randomly distributed into four groups: Color Cue Single task (CCS, blue and red, 9.8(3)cm(3)), Color Cue Dual task (CCD), No Cue (NC) and Size Cue (SC, 9.8(3) and 6(3)cm(3)) group. All groups performed a repetitive precision grasp-lift task and were retested with the same protocol after a 5-min pause. The CCD group was also required to simultaneously perform a memory task during each lift of differently weighted objects coded by color. The results show that groups lifting objects with arbitrary or familiar features successfully formed the association between object weight and manipulated object features and incorporated this into grip force programming, as observed in the different scaling of grip force and grip force rate for different object weights. An arbitrary feature, i.e., color, can be sufficiently associated with object weight, however with less strength than the familiar feature of size. The simultaneous memory task impaired anticipatory force scaling during repetitive object lifting but did not jeopardize the learning process and the consolidation of the associative memory.     

Does δ-sarcoglycan-associated autosomal-dominant cardiomyopathy exist?

In this study we clinically and genetically characterize a consanguineous family with a homozygous novel missense mutation in the δ-sarcoglycan gene and a second δ-sarcoglycan mutation that has previously been reported to cause severe autosomal-dominant dilated cardiomyopathy. We identified a novel missense mutation in exon 6 (p.A131P) of the δ-sarcoglycan gene, which in a homozygous state leads to the clinical picture of a limb girdle muscular dystrophy. In four heterozygous carriers for the mutation, aged 3–64 years, a second sequence variant in exon 6 (p.S151A) of the δ-sarcoglycan gene was detected on the other allele. This second missense change had previously been reported to be responsible for fatal autosomal-dominant dilated cardiomyopathy at young age. Comprehensive clinical and cardiac investigation in all of the compound heterozygous family members revealed no signs of cardiomyopathy or limb girdle muscular dystrophy. Our findings demonstrate that, even in the presence of a second disease-causing mutation, the p.S151A mutation in the δ-sarcoglycan gene does not result in cardiomyopathy. This finding questions the pathological relevance of this sequence variant for causing familial autosomal-dominant dilated cardiomyopathy and thereby the role of the δ-sarcoglycan gene in general as a disease-causing gene for autosomal-dominant dilated cardiomyopathy.     

Identification and Management of Women at High Risk for Hereditary Breast/Ovarian Cancer Syndrome

Abstract:  Despite advances in identifying genetic markers of high risk patients and the availability of genetic testing, it remains challenging to efficiently identify women who are at hereditary risk and to manage their care appropriately. HughesRiskApps, an open-source family history collection, risk assessment, and Clinical Decision Support (CDS) software package, was developed to address the shortcomings in our ability to identify and treat the high risk population. This system is designed for use in primary care clinics, breast centers, and cancer risk clinics to collect family history and risk information and provide the necessary CDS to increase quality of care and efficiency. This paper reports on the first implementation of HughesRiskApps in the community hospital setting. HughesRiskApps was implemented at the Newton-Wellesley Hospital. Between April 1, 2007 and March 31, 2008, 32,966 analyses were performed on 25,763 individuals. Within this population, 915 (3.6%) individuals were found to be eligible for risk assessment and possible genetic testing based on the 10% risk of mutation threshold. During the first year of implementation, physicians and patients have fully accepted the system, and 3.6% of patients assessed have been referred to risk assessment and consideration of genetic testing. These early results indicate that the number of patients identified for risk assessment has increased dramatically and that the care of these patients is more efficient and likely more effective.     

Role of integrins and focal adhesion kinase in the orientation of dermal fibroblasts exposed to cyclic strain*

Stretch is applied to skin under normal physiological conditions, for example pregnancy, or artificially using soft tissue expanders. Because cells are known to orient in response to the application of mechanical forces, the current studies were carried out to assess the effects of stretch on dermal fibroblast orientation and cell signalling. Dermal fibroblasts were seeded onto collagen‐coated flexible membranes and grown to 70–80% confluence. Membranes were then deformed at 10 cycles per minute by the application of 135 mmHg subatmospheric pressure. This corresponded to strain levels of 0–24% from the centre to extremity of the flexible membrane. We show that a minimum of 15% cell stretch is required to significantly stimulate the fibroblast orientation response. focal adhesion kinase (FAK), p38 and Rho were activated in fibroblasts exposed to cyclic stretch and incubation of cells with anti‐integrin β1 before the application of stretch abrogated fibroblast orientation, as well as FAK, p38 and Rho activation. Fibroblast orientation in response to cyclic stretch is mediated at least in part by integrin β1 through phosphorylation of FAK, p38 and activation of Rho.     

Estimates of the Proportion of Older White Women Who Would Be Recommended for Pharmacologic Treatment by the New U.S. National Osteoporosis Foundation Guidelines

The new U.S. National Osteoporosis Foundation Clinician's Guide to Prevention and Treatment of Osteoporosis includes criteria for recommending pharmacologic treatment based on history of hip or vertebral fracture, femoral neck (FN), or spine BMD T‐scores ≤?2.5 and presence of low bone mass at the FN or spine plus a 10‐yr risk of hip fracture ≥3% or of major osteoporotic fracture ≥20%. The proportion of women who would be recommended for treatment by these guidelines is not known. We applied the NOF criteria for treatment to women participating in the Study of Osteoporotic Fractures (SOF). To determine how the SOF population differs from the general U.S. population of white women ≥65 yr of age, we compared women in SOF with women who participated in the National Health and Nutrition Examination Survey (NHANES) III on criteria included in the NOF treatment guidelines that were common to both cohorts. Compared with NHANES III, women in SOF had higher FN BMD and were younger. Application of NOF guidelines to SOF data estimated that at least 72% of U.S. white women ≥65 yr of age and 93% of those ≥75 yr of age would be recommended for drug treatment. Application of the new NOF Guidelines would result in recommending a very large proportion of white women in the United States for pharmacologic treatment of osteoporosis.     

Fetuin‐A and BMD in Older Persons: The Health Aging and Body Composition (Health ABC) Study

Fetuin‐A is a hepatic secretory protein that promotes bone mineralization in vitro. Whether fetuin‐A levels are associated with BMD in humans is unknown. The Health Aging and Body Composition study enrolled 3075 well‐functioning black and white persons 70–79 yr of age and measured BMD. This cross‐sectional study measured serum fetuin‐A using ELISA among a random sample of 508 participants within sex and race strata. Multivariate linear regression analysis evaluated the associations of fetuin‐A with BMD. Among women (n = 257), higher fetuin‐A levels were significantly associated with higher total hip (p = 0.02), lumbar spine (p = 0.03), and whole body BMD (p = 0.01) in models adjusted for age, race, diabetes, alcohol and tobacco use, physical activity, body mass index, C‐reactive protein levels, calcium supplement, and estrogen use. For example, each SD (0.38 g/liter) higher level of fetuin‐A was associated with 0.016 g/cm² higher total hip areal BMD. The association was of similar magnitude and direction for femoral neck BMD but did not reach statistical significance (p = 0.11). In contrast, among men (n = 251), fetuin‐A had no significant associations with total hip (p = 0.79), lumbar spine (p = 0.35), whole body (p = 0.46), or femoral neck BMD (p = 0.54) in multivariable models. We conclude that higher fetuin‐A levels are independently associated with higher BMD among well‐functioning community‐dwelling older women but not older men. Future studies should evaluate whether fetuin‐A may refine fracture risk assessment in older women.