Technical validation of a new microfluidic device for enrichment of CTCs from large volumes of blood by using buffy coats to mimic diagnostic leukapheresis products.

Diagnostic leukapheresis (DLA) enables to sample larger blood volumes and increases the detection of circulating tumor cells (CTC) significantly. Nevertheless, the high excess of white blood cells (WBC) of DLA products remains a major challenge for further downstream CTC enrichment and detection. To address this problem, we tested the performance of two label-free CTC technologies for processing DLA products. For the testing purposes, we established ficollized buffy coats (BC) with a WBC composition similar to patient-derived DLA products. The mimicking-DLA samples (with up to 400 × 106 WBCs) were spiked with three different tumor cell lines and processed with two versions of a spiral microfluidic chip for label-free CTC enrichment: the commercially available ClearCell FR1 biochip and a customized DLA biochip based on a similar enrichment principle, but designed for higher throughput of cells. While the samples processed with FR1 chip displayed with increasing cell load significantly higher WBC backgrounds and decreasing cell recovery, the recovery rates of the customized DLA chip were stable, even if challenged with up to 400 × 106 WBCs (corresponding to around 120 mL peripheral blood or 10% of a DLA product). These results indicate that the further up-scalable DLA biochip has potential to process complete DLA products from 2.5 L of peripheral blood in an affordable way to enable high-volume CTC-based liquid biopsies.

Biomechanical comparison of a new expandable intramedullary nail and conventional intramedullary nails for femoral osteosynthesis in dogs.

Intramedullary nailing of diaphyseal femoral fractures is a commonly used treatment method in dogs because of its biological and biomechanical advantages compared to bone plating. To achieve adequate resistance of the intramedullary nail against torsional and axial compressive forces, additional application of transcortical screws is needed. As these interlocking screws represent a frequent cause of post-operative complications, a new expandable intramedullary nail (EXPN) was developed, which was designed to provide adequate fracture stabilisation without the need for transcortical fixation. The evaluation of the biomechanical properties of the new EXPN with regard to torsional, compressive and bending stability as well as direct comparison to the biomechanical properties of conventional Steinmann (STMN)- and interlocking (ILN) nails was carried out with different biomechanical test arrangements. No significant statistical differences regarding the torsional and bending resistance between the EXPN and ILN group were seen, which indicates that rotatory as well as bending stability of the innovative EXPN is similar to the conventional ILN. Nevertheless, the percentage deviation between the attempted and successfully reached physiological compressive forces was significantly higher (p = 0.045) in the EXPN group compared to the ILN group, which indicates that the compressive stability of the innovative EXPN might be weaker compared to the ILN. In summary, the new EXPN represents an interesting alternative to conventional intramedullary nails. However, in direct comparison to conventional interlocking nails, the EXPN has shown weaknesses in the neutralization of axial compressive forces, which indicates that at least biomechanically the interlocking nail seems advantageous. Further in-vitro and in-vivo investigations are required before clinical use can be recommended.

Influence of Hip Prosthesis Size and Its Coating Area on Bone Remodeling.

We developed a numerical model to describe the bone remodeling process in periprosthetic bone tissues and validated it by means of dual energy X-ray absorptiometry methods with different types of hip implants. In this paper, we applied the numerical model to investigate the influence of implant size and of the size of the porous coated area on bone remodeling in a periprosthetic human femur in an effort to define properties of implants, which would reduce bone remodeling after total hip arthroplasty. Two different sizes of a newly designed implant and three different coating area sizes were investigated in this paper. The results show that the smaller the implant, the less bone remodeling occurs. Reducing prosthesis size by 2mm from all sides has decreased bone remodeling by 14.4%. Extending the coating area on both, lateral and medial parts of the implant, has decreased bone remodeling in the lateral part of the femur and increased it in the medial part. In conclusion, depending on these results, the oversized hip replacement would cause more bone resorption in the femur. Concerning the coating area, the manufacturer must find a compromise between the small coating area with less bone remodeling in the medial part of the femur as well as less primary stability and the bigger coating area with less bone remodeling in the lateral part of the femur, but with higher bone remodeling in its medial part and more primary stability.

Comparative measurements of bone mineral density and bone contrast values in canine femora using dual-energy X-ray absorptiometry and conventional digital radiography.

BACKGROUND: Aseptic loosening due to bone remodelling processes after total hip replacement is one common cause for revision surgery. In human medicine, dual-energy X-ray absorptiometry (DEXA) is the gold standard for quantitative evaluation of bone mineral density, whereas in veterinary medicine conventional radiography is used for follow-up studies. Recently, a method has been described using digital X-ray images for quantitative assessment of grey scale values of bone contrast. Therefore, the aim of the present study was to evaluate the correlation of bone mineral density (BMD) measured by DEXA with grey scale values (GV) measured in digital X-ray images (RX50, RX66) ex vivo. RESULTS: The measured GV in the chosen X-ray settings showed on average a good correlation (r = 0.61) to the measured BMD with DEXA. Correlation between the two X-ray settings was very good (r = 0.81). For comparisons among regions of interests (ROIs) a difference of 8.2% was found to be statistically significant, whereas in the case of RX50 and RX66 differences of 5.3% and 4.1% were found to be statistically significant. CONCLUSIONS: Results indicate that measuring absolute changes in bone mineral density might be possible using digital radiography. Not all significant differences between ROIs detectable with DEXA can be displayed in the X-ray images because of the lower sensitivity of the radiographs. However, direct comparison of grey scale values of the periprosthetic femur in one individual patient during the follow-up period, in order to predict bone remodelling processes, should be possible, but with a lesser sensitivity than with DEXA. It is important that the same X-ray settings are chosen for each patient for follow-up studies.

Analysis of DNA methylation in single circulating tumor cells.

Direct analysis of circulating tumor cells (CTCs) can inform on molecular mechanisms underlying systemic spread. Here we investigated promoter methylation of three genes regulating epithelial-to-mesenchymal transition (EMT), a key mechanism enabling epithelial tumor cells to disseminate and metastasize. For this, we developed a single-cell protocol based on agarose-embedded bisulfite treatment, which allows investigating DNA methylation of multiple loci via a multiplex PCR (multiplexed-scAEBS). We established our assay for the simultaneous analysis of three EMT-associated genes miR-200c/141, miR-200b/a/429 and CDH1 in single cells. The assay was validated in solitary cells of GM14667, MDA-MB-231 and MCF-7 cell lines, achieving a DNA amplification efficiency of 70% with methylation patterns identical to the respective bulk DNA. Then we applied multiplexed-scAEBS to 159 single CTCs from 11 patients with metastatic breast and six with metastatic castration-resistant prostate cancer, isolated via CellSearch (EpCAMpos/CKpos/CD45neg/DAPIpos) and subsequent FACS sorting. In contrast to CD45pos white blood cells isolated and processed by the identical approach, we observed in the isolated CTCs methylation patterns resembling more those of epithelial-like cells. Methylation at the promoter of microRNA-200 family was significantly higher in prostate CTCs. Data from our single-cell analysis revealed an epigenetic heterogeneity among CTCs and indicates tumor-specific active epigenetic regulation of EMT-associated genes during blood-borne dissemination.

Numerical investigations of stress shielding in total hip prostheses.

Aseptic loosening of the prosthesis is still a problem in artificial joint implants. The loosening can be caused by, among other factors, resorption of the bone surrounding the prosthesis owing to stress shielding. In order to find out the influence of the prosthesis type on post-operative stress shielding, a static finite element analysis of a femur provided with the conventional uncemented stem BICONTACT and of one with the femoral neck prosthesis SPIRON was carried out. Strain energy densities and maximal principal strain distributions were calculated and compared with the physiological situation. Here, stress shielding was demonstrated in both periprosthetic femora. To determine the areas of the stress shielding, the bone in each FE model was subdivided into three regions of interest (ROI): proximal, diaphyseal, and distal. The numerical computations show stress shielding in the proximal ROI of both periprosthetic femora. Diaphyseally, the femoral neck prosthesis SPIRON, in contrast to the conventional uncemented long-stem prosthesis BICONTACT, causes no decrease in the strain distribution and thus no stress shielding. Distally, no change in the load distribution of either periprosthetic femur could be found, compared with the physiological situation.

Strain adaptive bone remodelling: influence of the implantation technique.

Total hip arthroplasties (THA) can be performed with cemented and uncemented femoral components. Aseptic loosening of the joint replacement still illustrates a problem for both implantation techniques. This loosening can be caused, among other factors, by resorption of the bone surrounding the implant due to stress shielding. In order to analyse the absolute influence of the implantation technique on the bone degeneration in the periprosthetic femur, the strain adaptive bone remodelling after THA was investigated in a three-dimensional finite element (FE) simulation of a femur provided with a cemented and uncemented BICONTACT (Aesculap, Tuttlingen, Germany) femoral component. For this, a bone density evolution theory was implemented in the FE code MSC.MARC. In these static FE simulations, the muscle and hip resultant forces represent the maximum loading situation in the normal walking cycle. To describe the mechanical properties of the bone, an isotropic material law dependent upon density was used. The situation directly after implantation without any bone ingrowth was simulated. The cemented femoral component was bonded to the bone by a homogenous cement mantle. The numerical results show that proximally, the bone resorption areas surrounding the BICONTACT stem are heavily dependent upon anchoring technique. Furthermore, no significant bone remodelling is calculated in the distal periprosthetic femur in both models.

Problems with ultrasonic measurements of shear modules of structured media.

The elastic constants of linearly elastic, isotropic or anisotropic bone material are required for many numerical simulations. These constants are often measured ultrasonically, but this can lead to mistakes, especially if shear modules of spongiosa are considered. The reason is that spongiosa is a structure composed of trabeculae, each of which acts as a kind of beam which allows longitudinal, shear and also bending waves to propagate; the bending waves are as fast as the longitudinal waves and are indistinguishable from the shear waves. Furthermore, mistakes in measuring Young's modulus cannot be avoided in every case. Several numerical simulations of wave propagations in homogeneous media, and especially in periodically and irregularly structured media, were carried out via the application of explicit finite element codes. Results showing the above-mentioned effects are presented and discussed. These can help to explain in detail why mistakes may occur during ultrasonic measurements.

[Determination of the elastic properties of the compact bone in the femur of dogs]. / Ermittlung der elastischen Eigenschaften der Kompakta im Femur des Hundes.

Total hip endoprotheses are a good possibility for treatment degenerative wear and pathologic damage of the hip joint in man as well as in dogs. However, aseptic loosening of the protheses, especially in the area of the shaft, is still a problem in conventional total hip endoprotheses. The purpose of the present study was to use the finite-element-analysis (FEA), to enhance endoprothetic design and to prevent loosening of protheses. In order to simulate the femur of the dog for numerical analysis, a material law for the compacta in the femur of the dog was developed. The elastic properties of the compacta were experimentally determined by using compression tests of bone samples of euthanised dogs. The results show constant denseness and a constant axial elastic modul in the compacta.

Cystic solitary intracerebral metastasis from prostate adenocarcinoma.

Brain metastases from prostate adenocarcinoma are rare; spread to brain as the only site of metastasis is even rarer. We present a patient with a large, cystic, solitary intracerebral metastasis from prostate adenocarcinoma. The pertinent literature is reviewed.

Measurement of the lambda(+)(c) lifetime.

The Lambda+c lifetime is measured using 9.0 fb(-1) of e+e- annihilation data collected on or just below the Upsilon(4S) resonance with the CLEO II.V detector at CESR. Using an unbinned maximum likelihood fit, the Lambda+c lifetime is measured to be 179.6+/-6.9(stat)+/-4.4(syst) fs. The precision of this colliding beam measurement is comparable to other measurements, which are based on fixed-target experiments, with different systematic uncertainties.

Can skills training prevent relationship problems in at-risk couples? Four-year effects of a behavioral relationship education program.

Eighty-three couples were stratified into groups at high and low risk for relationship distress and randomized to either the Self-Regulatory Prevention and Relationship Enhancement Program (Self-PREP) or a control condition. As predicted, there were differential effects of Self-PREP on high-risk and low-risk couples. Because of low statistical power, results must be interpreted cautiously, but at 1-year follow-up high-risk couples in Self-PREP showed trends toward better communication than control couples. However, there was no difference in the communication of Self-PREP and control low-risk couples. High-risk couples receiving Self-PREP exhibited higher relationship satisfaction at 4 years than control couples, but in low-risk couples relationship satisfaction was higher in the control condition. High-risk couples seemed to benefit from skills-based relationship education, but low-risk couples did not.

Search for CP violation in B+/- --> J/psiK+/- and B+/- --> psi(2S)K+/- decays.

We present a search for direct CP violation in B+/--->J/psiK+/- and B+/--->psi(2S)K+/- decays. In a sample of 9.7x10(6) B&Bmacr; meson pairs collected with the CLEO detector, we have fully reconstructed 534 B+/--->J/psiK+/- and 120 B+/--->psi(2S)K+/- decays with very low background. We have measured the CP-violating charge asymmetry to be [+1.8+/-4.3(stat)+/-0.4(syst)]% for B+/--->J/psiK+/- and [+2.0+/-9. 1(stat)+/-1.0(syst)]% for B+/--->psi(2S)K+/-.

Repeating the errors of our parents? Family-of-origin spouse violence and observed conflict management in engaged couples.

Based on a developmental social learning analysis, it was hypothesized that observing parental violence predisposes partners to difficulties in managing couple conflict. Seventy-one engaged couples were assessed on their observation of parental violence in their family of origin. All couples were videotaped discussing two areas of current relationship conflict, and their cognitions during the interactions were assessed using a video-mediated recall procedure. Couples in which the male partner reported observing parental violence (male-exposed couples) showed more negative affect and communication during conflict discussions than couples in which neither partner reported observing parental violence (unexposed couples). Couples in which only the female partner reported observing parental violence (female-exposed couples) did not differ from unexposed couples in their affect or behavior. Female-exposed couples reported more negative cognitions than unexposed couples, but male-exposed couples did not differ from unexposed couples in their reported cognitions.

Identification and molecular analysis of lbpBA, which encodes the two-component meningococcal lactoferrin receptor.

We identified lbpB, encoding the lipoprotein component of the meningococcal lactoferrin receptor. An LbpB mutant was unable to acquire Fe from lactoferrin and exhibits decreased surface binding to lactoferrin. Primer extension and reverse transcription-PCR analysis indicate that lbpB and lbpA are cotranscribed on a polycistronic Fe-repressible mRNA.

The relationship between low family income and psychological disturbance in young children: an Australian longitudinal study.

OBJECTIVE: This study examines the relationship between low family income (LFI) experienced at different points in time, chronic low income status and its impact on child behaviour measured at 5 years of age. METHOD: Longitudinal data from the Mater University Study of Pregnancy were used to measure LFI in families at three points in time (the antenatal period, 6 months post birth and at 5 years cf age). Outcome variables were three independent groups of behaviour problems labelled as externalising, social, attentional and thought (SAT) problems, and internalising problems. These groups were developed from the Child Behaviour Checklist. An analysis based on logistic regression modelling was carried out examining the relationship between LFI and a range of intermediate variables known to be associated with child behaviour problems. RESULTS: The more often families experienced low income, the higher the rate of child behaviour problems at age 5. Low family income was still independently associated with SAT behaviour problems after controlling for smoking in the first trimester, parenting styles, maternal depression and marital dysharmony at age 5. The association between LFI and internalising and externalising behaviour problems was largely mediated by maternal depression. CONCLUSION: Low family income is a significant factor in the aetiology of a variety of child behaviour problems. The mechanisms involved in the link between LFI and childhood internalising and externalising behaviours involve the exposure of the children to maternal depression. However, the relationship between LFI and SAT behaviour problems remains to be elucidated.

Impact of family type and family quality on child behavior problems: a longitudinal study.

OBJECTIVE: In the context of substantial changes in family types and even family quality in recent times, this study is concerned with the extent to which family type and quality impacts on child behavior problems. METHOD: A sample of 8,556 pregnant women were enrolled in a prospective, longitudinal study. Details of changes in family type and family quality (assessed using Spanier Dyadic Adjustment Scale) were used to predict three second-order syndromes developed from the Child Behavior Checklist and administered to the mothers when the child was 5 years of age. RESULTS: Mothers who experienced no partner changes (married and single) reported the lowest rates of child behavior problems for the three syndromes used in this study. In addition, mothers who more often described their relationship with their partner as poor also reported the highest rate of child behavior problems across all three syndromes. Adjustment for possible confounders did not alter these findings. CONCLUSION: Both changes of partner and dyadic conflict appear to lead to child behavior problems, with the latter factor appearing to have a greater impact than the former. Mothers who experienced no partner changes and no conflict appeared to have children with the fewest behavior problems.

Tapping the power of information: an orientation for academic medical centers.

In September 1994 the Association of American Medical Colleges' (AAMC's) Advisory Panel on the Mission and Organization of Medical Schools (APMOMS) established a working group to address both the long-term and the immediate implications of the expanding capacity of and need for information technology (IT) within academic medical centers (i.e., medical schools and teaching hospitals). Over a two-year period, group members assessed the utilization of IT through surveys of current practices and interactions with acknowledge leaders in the field. They also had discussions with deans and other institutional leaders. The group developed the consensus that proper use of currently available IT is crucial to virtually every aspect of academic medicine's clinical, educational, and research missions. Moreover, current IT technology will be further enhanced by the powerful new applications that are nearing deployment. All group members agreed that IT must become a core competency of academic and medical centers (AMCs), the profession, and individual physicians and scientists to ensure the survival of AMCs in the current highly competitive environments. The authors outline their arguments for the development of strong information systems within AMCs and present basic characteristics of systems that show promise for successful implementation. The y review some of the major institutional obstacles that have hindered the planing and implementation of IT. They conclude with a list of practical institution strategies for success in planning and implementing IT systems, and suggestions for how the AAMC can help members achieve success in these activities.