Antegrade femoral nailing in the lateral decubitus position: a case series, technical tips and review of literature.

BACKGROUND: Femoral intramedullary nailing is traditionally performed with the patient supine on a fracture table. We aimed to describe a case series of femoral intramedullary nailing for fracture in the lateral position, with discussion of the operative technique. METHODS: A retrospective analysis identified 52 patients who underwent femoral intramedullary nailing performed in a lateral position without traction over a 5-year period at a single level 1 trauma center. Medical records were reviewed for demographics, blood loss including need for transfusion, operative duration, complications, length of stay, fracture union, re-operation and death. RESULTS: There were 24 subtrochanteric, 16 peri-trochanteric and 12 diaphyseal femoral fractures. Mean operative time was 136.2 ± 101.4 min with a mean estimated blood loss of 372.5 ± 349.6 ml. Seventeen patients required blood transfusion. Mean length of stay was 10.3 ± 8.1 days. There were 3 (5.8%) surgical (compartment syndrome, infection and retained drain) and 12 (23.1%) medical complications, with a 30-day mortality rate of 3.8% (2). Mean follow-up was 9.9 ± 8.7 months. The union rate was 94.2% (49) and 3.8% (2) patients required revision fixation (hardware exchange for irritation and exchange nailing for non-union). Discharge destination was home, rehabilitation center and specialized nursing facility in 21 (40.4%), 16 (30.8%) and 15 (28.8%) patients, respectively. DISCUSSION AND CONCLUSION: Femoral intramedullary nailing in the lateral decubitus position is a useful technique of managing peri-trochanteric, subtrochanteric and diaphyseal femoral fractures. We describe a known technique with technical tips, which has distinct advantages over traditional supine positioning especially in certain patient and fracture types. In addition, operative times, blood loss, length of stay, revision and outcomes were comparable to the literature.

Pipkin type IV femoral head fractures: a case series and review of literature.

INTRODUCTION: Femoral head fractures with associated acetabular fractures are uncommon injuries usually resulting from high-energy mechanisms such as motor vehicle collisions. Outcomes of Pipkin type IV fractures have been historically poor, with high rates of osteonecrosis, post-traumatic arthritis, and heterotopic ossification. The objective of this study was to define the outcomes of operatively treated Pipkin type IV fractures In addition, we reviewed the available literature of this uncommon injury pattern. METHODS: A retrospective chart review at a single level 1 trauma center from 2007 to 2016 identified 10 patients with Pipkin IV femoral head fractures. Demographic information, fracture type, associated injuries, operative details, and complications were evaluated. Clinical and radiological outcomes were assessed at latest follow-up including conversion to total hip arthroplasty. RESULTS: Six of the seven patients were treated with open reduction and internal fixation of the femoral head fracture and acetabular fracture through a Kocher-Langenbeck approach aided by a trochanteric flip and one had fragment excision. Six patients (87.5%) developed post-traumatic arthritis. Four (57.1%) later underwent conversion to total hip arthroplasty (THA) a mean of 20.5 months after index procedure. CONCLUSION: Our study shows a rate of osteonecrosis and osteoarthritis that is even higher than the previously reported studies. The former may relate to longer-term follow-up and the latter possibly due to associated comminuted posterior wall fracture.

Retrospective evidence for a biological cost of vancomycin resistance determinants in the absence of glycopeptide selective pressures.

OBJECTIVES: To estimate the relative fitness differences between glycopeptide-resistant Enterococcus faecium (GREF) and glycopeptide-susceptible E. faecium (GSEF) from yearly surveillance data on the occurrence of GREF in Danish poultry farm environments. METHODS: A population genetic model was adapted to retrospectively estimate the biological fitness cost of acquired resistance. Maximization of a likelihood function was used to predict the longitudinal persistence of acquired resistance. RESULTS: Our analysis suggests strong selection against GREF following the 1995 ban on the glycopeptide growth promoter avoparcin. However, parameterizing the model with two selection coefficients suggesting a reduced negative effect of the acquired resistance on bacterial fitness over time significantly improved the fit of the model. Our analyses suggest that the acquired glycopeptide resistance will persist for >25 years. CONCLUSIONS: Acquired resistance determinants in commensal E. faecium populations in Danish farm environments are likely to persist for decades, even in the absence of glycopeptide use.

Tn1546 is part of a larger plasmid-encoded genetic unit horizontally disseminated among clonal Enterococcus faecium lineages.

OBJECTIVES: To determine the genetic composition of the first VanA-type plasmid (pIP816) reported, which was isolated from a clinical Enterococcus faecium (BM4147) strain in France in 1986, and to reveal the genetic units responsible for the dissemination of the vanA gene cluster by comparisons with current, published and additionally generated vanA-spanning plasmid sequences obtained from a heterogeneous E. faecium strain collection (n = 28). METHODS: Plasmid sequences were produced by shotgun sequencing using ABI dye chemistry and primer walking, and were subsequently annotated. Comparative sequence analysis of the vanA region was done with published plasmids, with a partial vanA plasmid (pVEF4) reported here and to >140 kb of sequence obtained from a collection of vanA-harbouring plasmid fragments. RESULTS: Bioinformatic analyses revealed that pIP816 from 1986 and contemporary vanA plasmids shared a conserved genetic fragment of 25 kb, spanning the 10.85 kb vanA cluster encoded by Tn1546, and that the larger unit is present in both clinical and animal complexes of E. faecium. A new group II intron in pVEF4 was characterized. CONCLUSIONS: Comparative DNA analyses suggest that Tn1546 disseminates in and between clonal complexes of E. faecium as part of a larger genetic unit, possibly as a composite transposon flanked by IS1216 elements.

Computer-assisted scanning electron microscopy of wood pulp fibres: dimensions and spatial distributions in a polypropylene composite.

A shape description approach is introduced as a step for performing an automatic processing of fibre cross-sectional images. The approach, in combination with appropriate mathematical morphology, yields edited images, which are suitable for further computerized image analysis. Important parameters such as fibre wall thickness, fibre perimeter, form factor and collapse index are quantified effectively and objectively. Although some differences are encountered within groups of split fibres, manual and automatic quantification of intact fibres yields similar results. In addition, the suitability of a distance transform approach for quantifying the fibre inter-distances in composites is demonstrated. Such tools will be valuable for understanding the mechanical properties of engineered fibre-reinforced composite materials.

Episodic selection and the maintenance of competence and natural transformation in Bacillus subtilis.

We present a new hypothesis for the selective pressures responsible for maintaining natural competence and transformation. Our hypothesis is based in part on the observation that in Bacillus subtilis, where transformation is widespread, competence is associated with periods of nongrowth in otherwise growing populations. As postulated for the phenomenon of persistence, the short-term fitness cost associated with the production of transiently nongrowing bacteria can be compensated for and the capacity to produce these competent cells can be favored due to episodes where the population encounters conditions that kill dividing bacteria. With the aid of a mathematical model, we demonstrate that under realistic conditions this "episodic selection" for transiently nongrowing (persisting) bacteria can maintain competence for the uptake and expression of exogenous DNA transformation. We also show that these conditions for maintaining competence are dramatically augmented even by rare episodes where selection favors transformants. Using experimental populations of B. subtilis and antibiotic-mediated episodic selection, we test and provide support for the validity of the assumptions behind this model and the predictions generated from our analysis of its properties. We discuss the potential generality of episodic selection for the maintenance of competence in other naturally transforming species of bacteria and critically evaluate other hypotheses for the maintenance (and evolution) of competence and their relationship to this hypothesis.

Complete sequence of Enterococcus faecium pVEF3 and the detection of an omega-epsilon-zeta toxin-antitoxin module and an ABC transporter.

Glycopeptide resistant Enterococcus faecium (GREF) persists on Norwegian poultry farms despite the ban on the growth promoter avoparcin. The biological basis for long-term persistence of avoparcin resistance is not fully understood. This study presents the complete DNA sequence of the E. faecium R-plasmid pVEF3 and functional studies of some plasmid-encoded traits (a toxin-antitoxin (TA) system and an ABC transporter) that may be of importance for plasmid persistence. The pVEF3 (63.1 kbp), isolated from an E. faecium strain of poultry origin sampled in Norway in 1999, has 71 coding sequences including the vanA avoparcin/vancomycin resistance encoding gene cluster. pVEF3 encodes the TA system omega-epsilon-zeta, and plasmid stability tests and transcription analysis show that omega-epsilon-zeta is functional in Enterococcus faecalis OGIX, although with decreasing effect over time. The predicted ABC transporter was not found to confer reduced susceptibility to any of the 28 substances tested. The TA system identified in the pVEF-type plasmids may contribute to vanA plasmid persistence on Norwegian poultry farms. However, size and compositional heterogeneity among E. faecium vanA plasmids suggest that additional plasmid maintenance systems in combination with host specific factors and frequent horizontal gene transfer and rearrangement causes the observed plasmid composition and distribution patterns.

Comparative DNA analysis of two vanA plasmids from Enterococcus faecium strains isolated from poultry and a poultry farmer in Norway.

The DNA sequences of two plasmids carrying vanA, pVEF1 (39,626 bp) and pVEF2 (39,714 bp), were determined. Forty-three shared coding sequences were identified, and the only nucleotide difference was an 88-bp indel. A postsegregational killing system was identified. This system possibly explains the persistence of the vanA gene cluster in Norwegian poultry farms.

Prevalence, persistence, and molecular characterization of glycopeptide-resistant enterococci in Norwegian poultry and poultry farmers 3 to 8 years after the ban on avoparcin.

Environmental reservoirs of glycopeptide-resistant enterococci (GRE) in Norway have been linked to former growth promoting use of the glycopeptide avoparcin in poultry production. We have examined the prevalence of fecal GRE in poultry and poultry farmers 3 to 8 years after the Norwegian avoparcin ban in 1995 and performed molecular analyses of the GRE population. Fecal samples from poultry farmers and their flocks on 29 previously avoparcin-exposed farms were collected on five occasions during the study period (1998 to 2003). All flocks (100%) were GRE positive in 1998. Throughout the study period, 78.5% of the poultry samples were GRE positive. Glycopeptide-resistant Enterococcus faecium (GREF) was isolated from 27.6% of the farmer samples in 1998 and from 27.8% of the samples collected between 1998 and 2003. The prevalence of fecal GRE in poultry declined significantly during the study period, but prevalence in samples from the farmers did not decline. PCR analysis revealed a specific Tn1546-plasmid junction fragment in 93.9% of E. faecium isolates. A putative postsegregation killing (PSK) system linked to Tn1546 was detected in 97.1% of the isolates examined. Multilocus sequence typing of glycopeptide-susceptible (n = 10) and -resistant (n = 10) E. faecium isolates from humans (n = 10) and poultry (n = 10) on two farms displayed 17 different sequence types. The study confirms the continuing persistence of a widespread common plasmid-mediated vanA-pRE25-PSK element within a heterogeneous GRE population on Norwegian poultry farms 8 years after the avoparcin ban. Moreover, it suggests an important role of PSK systems in the maintenance of antimicrobial resistance determinants in reservoirs without apparent antimicrobial selection.

PNMT transgenic mice have an aggressive phenotype.

PNMT (phenylethanolamine-N-methyl-transferase) is the enzyme that catalyzes the formation of epinephrine from norepinephrine. In transgenic mice over-expressing PNMT, observations revealed a very high level of aggression compared to their background strain, C57BL/6J. To evaluate the influence of PNMT on aggression and emotionality in this transgenic line, single-sex male and female groups were independently established that consisted of either four wild-type mice or four transgenic mice overexpressing PNMT. The members of each group were littermates. Mixed single-sex groups consisting of two transgenic mice and two wild-type mice were also established. Almost no fights were observed within the female groups. In males, the transgenic line showed a significantly higher level of fighting than controls (p=0.007) and mixed male groups (p=0.02). Housing mice from the transgenic line in mixed groups with wild-type mice seems to decrease the level of aggression in the transgenic line. In conclusion, this is the first study to demonstrate a clear, significant increase in aggression arising from PNMT overexpression. This suggests an important role for central epinephrine levels in aggressive behavior.

Persistence of animal and human glycopeptide-resistant enterococci on two Norwegian poultry farms formerly exposed to avoparcin is associated with a widespread plasmid-mediated vanA element within a polyclonal enterococcus faecium population.

The evolutionary processes responsible for the long-term persistence of glycopeptide-resistant Enterococcus faecium (GREF) in nonselective environments were addressed by genetic analyses of E. faecium populations in animals and humans on two Norwegian poultry farms that were previously exposed to avoparcin. A total of 222 fecal GREF (n = 136) and glycopeptide-susceptible (n = 86) E. faecium (GSEF) isolates were obtained from farmers and poultry on three separate occasions in 1998 and 1999. Pulsed-field gel electrophoresis (PFGE) and plasmid DNA analyses discerned 22 GREF and 32 GSEF PFGE types within shifting polyclonal animal and human E. faecium populations and indicated the presence of transferable plasmid-mediated vanA resistance, respectively. Examples of dominant, persistent GREF PFGE types supported the notion that environmentally well-adapted GREF types may counteract the reversal of resistance. PFGE analyses, sequencing of the purK housekeeping gene, and partial typing of vanA-containing Tn1546 suggested a common animal and human reservoir of glycopeptide resistance. Inverse PCR amplification and sequence analyses targeting the right end of the Tn1546-plasmid junction fragment strongly indicated the presence of a common single Tn1546-plasmid-mediated element in 20 of 22 GREF PFGE types. This observation was further strengthened by vanY-vanZ hybridization analyses of plasmid DNAs as well as the finding of a physical linkage between Tn1546 and a putative postsegregation killing system for seven GREF PFGE types. In conclusion, our observations suggest that the molecular unit of persistence of glycopeptide resistance is a common mobile plasmid-mediated vanA-containing element within a polyclonal GREF population that changes over time. In addition, we propose that "plasmid addiction systems" may contribute to the persistence of GREF in nonselective environments.

Controlled serial grinding for high-resolution three-dimensional reconstruction.

This work reports an improved preparation procedure for acquiring SEM images for three-dimensional (3D) reconstruction. The images are acquired consecutively after serial grinding and polishing. Ugelstad beads are used as landmarks for registration purposes and for determining the thickness of the abraded sections. An estimation of the bead sizes necessary for suitable thickness quantification at the corresponding spatial resolution and uncertainty is given. Shape-based interpolation is used for filling the gaps between the cross-sections. An indication of the distance between cross-sections necessary for good interpolation is also given. An example of a 3D reconstructed paper volume is presented. The method is suitable for preparation of fibre and paper as well as other materials.

Effects of farnesol and the off-flavor derivative geosmin on Streptomyces tendae.

Effects of the sesquiterpene farnesol (3,7,11-trimethyl-2,6,10-dodecatrien-1-ol) and the sesquiterpene derivative geosmin (1,10-trans-dimethyl-trans-9-decalol) were investigated in a geosmin-producing actinomycete, Streptomyces tendae. Exposure to 300 microM farnesol reduced biomass (fresh matter) accumulation by 97% compared with biomass accumulation by controls, whereas an equal amount of geosmin did not affect biomass accumulation. Increasing exposure to farnesol corresponded with reduced optical density of the culture, reduced levels of geosmin, and reduced metabolic heat production compared with controls, while exogenous geosmin did not affect these parameters. Geosmin dissipated from unioculated medium more rapidly than farnesol, indicating that in addition to the lower toxicity of geosmin, the actual exposure to geosmin over time may be less than exposure to an equal amount of farnesol. Cultures grown on Actinomyces-B medium contained 99.5% less geosmin and were more sensitive to farnesol than those grown on Hickey-Tresner medium, indicating that geosmin synthesis was associated with reduced sensitivity to farnesol. Consumption of farnesyl moieties during geosmin synthesis may reduce the potential for farnesol-induced inhibition of growth and metabolism.

Aquaculture product quality issues: market position opportunities under mandatory seafood inspection regulations.

Impending legislation for a mandatory seafood inspection program will be important in shaping the consumer's perception and expectation of quality in seafood products. Because aquacultured species are produced in controlled environments, fed special diets, and processed under optimum conditions, they possess unique product characteristics. The perception by the consumer that these products could be safer, fresher, more wholesome, and better tasting may lead to a competitive marketing position relative to captured products.

Simplified method to quantify geosmin and 2-methylisoborneol concentrations in water and microbiological cultures.

A simple and rapid method for the extraction and quantification of geosmin and 2-methylisoborneol is described. Using methylene chloride extraction and gas chromatography, the procedure eliminates costly stripping devices. Recovery efficiency of the procedure is approximately 65% with a sensitivity equal to the human threshold for these two important off-flavor compounds.

Sex pheromones of the sea lamprey (Petromyzon marinus): Steroid studies.

Pheromone-containing and pheromone-devoid samples of male sea lamprey (Petromyzon marinus) urine were analyzed for the concentrations of nine steroids [dehydroepiandrosterone (DHEA), testosterone (T), dihydrotestosterone (DHT), progesterone (P), androstenedione (A), estrone (E1), estradiol (E2), corticosterone (B), and cortisol (F)] by radioimmunoassay (RIA). Samples analyzed included native urine that had been enzymatically hydrolyzed with mixed ß-glucuronidase/sulfatase. Values of the analyses were used to prepare solutions of the individual steroids for bioassay at concentrations which bracketed the urinary concentrations. Results show that only testosterone elicited a preference response in spawning-run female sea lampreys, and in concentrations three to four orders of magnitude greater than those found in active, unhydrolyzed male urine. The possibility that testosterone acts as a pheromone in this species is discussed.

What should adult children do for elderly parents? Opinions and preferences of three generations of women.

Three generations of women (N = 403) were surveyed to discover their opinions about appropriate filial behavior toward elderly parents and their personal preferences among various providers of services that they might need in old age. Opinions were elicited by a vignette focused on what hypothetical adult children with differing situational characteristics should do to help meet the needs of their dependent widowed mother. Preferences were obtained from subjects' rankings of six potential providers (representing formal and informal support systems) for eight types of services. In the responses to the vignette, adjustment of family schedules and help with costs of professional health care were seen as appropriate for adult children, but adjustment of work schedules and sharing of households were not. For themselves, the women preferred adult children as providers of emotional support and financial management but not of income. The middle generation was least in favor of receiving financial support or instrumental help from children, preferring formal services for such assistance.

Women's changing roles and help to elderly parents: attitudes of three generations of women.

Data on the effects of women's changing roles on attitudes toward responsibility for care of elderly adults were gathered from three generations of women (N = 403). Elderly women, middle-generation daughters, and young-adult granddaughters were compared on responses to Likert-scaled attitude items relating to gender-appropriate roles and care of elderly persons (including filial responsibility and acceptability of formal and informal supports). Significant generational differences occurred on attitude items relating to sharing of child care, parent care, and household tasks by men and women, but majorities of all generations were in favor of such sharing. The oldest generation was most receptive (and the youngest the least receptive) to formal services for elderly persons, but all three generations agreed that old people should be able to depend on adult children for help. Values about family care of elderly adults have not eroded despite demographic and socioeconomic changes.

Genetics of the low density lipoprotein receptor: I. Low density lipoprotein receptor activity in cultured fibroblasts from subjects with or without familial hypercholesterolemia.

Six indices of low density lipoprotein (LDL) receptor activity were assayed in cultured fibroblasts from seven subjects with familial hypercholesterolemia (HC) and six subjects without HC (non-HCs). Four non-HCs, three HC heterozygotes and one HC homozygous proband belonged to one kindred (kindred A). The proband's fibroblast 125I-LDL processing values fell within or were slightly above the range defined by fibroblasts from three "receptor-negative" HC homozygotes. Thus, the plasma membrane receptor defect in this kindred is probably of the "receptor-negative" category. LDL receptor-dependent 125I-LDL processing was about twice as high in fibroblasts from non-HCs as in those from HC heterozygotes belonging to kindred A. The segregation pattern of LDL receptor activity in this kindred was compatible with control by a single gene locus. 125I-LDL processing values from non-HCs, HC heterozygotes and HC homozygotes differed significantly from one another, but non-HCs and HC heterozygotes showed some overlap. LDL receptor-dependent 125I-LDL association (plasma membrane binding plus intracellular accumulation) data for 6 HC heterozygous and 13 non-HC fibroblast strains clustered into two and into three groups, respectively. Median 125I-LDL association levels in these groups appeared to be in agreement with hypothesis that two different geno-types in HC heterozygotes and three in non-HCs determined LDL receptor activity. These findings suggest the possibility that 125I-LDL processing studies may reveal "normal" alleles at the LDL receptor locus.