Consideration of multiple load cases is critical in modelling orthotropic bone adaptation in the femur

Functional adaptation of the femur has been investigated in several studies by embedding bone remodelling algorithms in finite element (FE) models, with simplifications often made to the representation of bone’s material symmetry and mechanical environment. An orthotropic strain-driven adaptation algorithm is proposed in order to predict the femur’s volumetric material property distribution and directionality of its internal structures within a continuum. The algorithm was applied to a FE model of the femur, with muscles, ligaments and joints included explicitly. Multiple load cases representing distinct frames of two activities of daily living (walking and stair climbing) were considered. It is hypothesised that low shear moduli occur in areas of bone that are simply loaded and high shear moduli in areas subjected to complex loading conditions. In addition, it is investigated whether material properties of different femoral regions are stimulated by different activities. The loading and boundary conditions were considered to provide a physiological mechanical environment. The resulting volumetric material property distribution and directionalities agreed with ex vivo imaging data for the whole femur. Regions where non-orthogonal trabecular crossing has been documented coincided with higher values of predicted shear moduli. The topological influence of the different activities modelled was analysed. The influence of stair climbing on the properties of the femoral neck region is highlighted. It is recommended that multiple load cases should be considered when modelling bone adaptation. The orthotropic model of the complete femur is released with this study.     

Lysosomal leukocyte beta-D-glucuronidase during enzyme replacement therapy in Fabry disease

OBJECTIVE: Fabry disease results from a deficiency in the activity of alpha-d-galactosidase A and subsequent accumulation of neutral glycosphingolipids in lysosomes. This study investigated whether lysosomal enzymes can indicate biochemical changes in the lysosomal apparatus induced by enzyme replacement therapy (ERT). DESIGN AND METHODS: Eight patients were monitored by clinical and biochemical tests and several lysosomal glycohydrolases were measured in plasma and leucocytes. RESULTS: Before starting ERT, beta-d-glucuronidase in leukocytes was markedly increased. After 1 month of therapy, enzyme levels dropped in all patients. In the patients who regularly followed the therapy, the enzyme levels remained stable for the next 20 months. In one patient who interrupted therapy for 2 months, the enzyme levels rose again. CONCLUSIONS: Lysosomal enzymes can be useful for monitoring biochemical changes in patients with Fabry disease receiving ERT. Though these findings refer to only a small number of patients, the correlation between beta-d-glucuronidase levels and ERT is interesting and might serve as a basis for further studies to define the potential of this enzyme in monitoring the effects of ERT in lysosomal storage disorders.     

Evaluation of the inhibitory effects of human serum components on bactericidal activity of human beta defensin 3

Naturally occurring cationic antimicrobial peptides (CAPs) are an essential component of the innate immune system of multicellular organisms. At concentrations generally higher than those found in vivo, most CAPs exhibit strong antibacterial properties in vitro, but their activity may be inhibited by body fluids, a fact that could limit their future use as antimicrobial and/or immunomodulatory agents. In the present study, we evaluated the effects of human serum components on bactericidal activity of the human beta-defensin 3 (hBD-3), a CAP considered particularly promising for future therapeutic employment. Human serum diluted to 20% strongly inhibited the bactericidal activity of the peptide against both the Gram-positive species Staphylococcus aureus and the Gram-negative species Acinetobacter baumannii. Such activity was not restored in serum devoid of salts (dialyzed), pre-treated with protease inhibitors, or subjected to both of these treatments. The addition of physiological concentrations of NaCl, CaCl2, and human albumin in the bactericidal assay abolished bactericidal activity of hBD-3 against S. aureus, while it only partially inhibited the activity of the peptide against A. baumannii. Although a proteolytic activity of serum on hBD-3 was demonstrated at the protein level by Western blot, addition of physiological concentrations of trypsin to the bactericidal assay only partially affected the antibacterial properties of the peptide. Altogether, these results demonstrate a major role of mono-divalent cations and serum proteins on inhibition of hBD-3 antibacterial properties and indicate a relative lack in sensitivity of the bactericidal activity of this peptide to trypsin and trypsin-like proteases.     

Long-Term Structural and Functional Myocardial Adaptations in Healthy Living Kidney Donors: A Pilot Study

Background and Aims

Compensatory renal hypertrophy following unilateral nephrectomy (UNX) occurs in the remaining kidney. However, the long-term cardiac adaptive process to UNX remains poorly defined in humans. Our goal was to characterize myocardial structure and function in living kidney donors (LKDs), approximately 12 years after UNX.

Methods and Results

Cardiac function and structure in 15 Italian LKDs, at least 5 years after UNX (median time from donation = 8.4 years) was investigated and compared to those of age and sex matched U.S. citizens healthy controls (n = 15). Standard and speckle tracking echocardiography (STE) was performed in both LKDs and controls. Plasma angiotensin II, aldosterone, atrial natriuretic peptide (ANP), N terminus pro B-type natriuretic peptide (NT-proBNP), cyclic guanylyl monophosphate (cGMP), and amino-terminal peptide of procollagen III (PIIINP) were also collected. Median follow-up was 11.9 years. In LKDs, LV geometry and function by STE were similar to controls, wall thickness and volumes were within normal limits also by CMR. In LKDs, CMR was negative for myocardial fibrosis, but apical rotation and LV torsion obtained by STE were impaired as compared to controls (21.4 ± 7.8 vs 32.7 ± 8.9 degrees, p = 0.04). Serum creatinine and PIIINP levels were increased [1.1 (0.9–1.3) mg/dL, and 5.8 (5.4–7.6)] μg/L, respectively), while urinary cGMP was reduced [270 (250–355) vs 581 (437–698) pmol/mL] in LKDs. No LKD developed cardiovascular or renal events during follow-up.

Conclusions

Long-term kidney donors have no apparent structural myocardial abnormalities as assessed by contrast enhanced CMR. However, myocardial deformation of the apical segments, as well as apical rotation, and LV torsion are reduced. The concomitant increase in circulating PIIINP level is suggestive of fibrosis. Further studies, focused on US and EU patients are warranted to evaluate whether these early functional modifications will progress to a more compromised cardiac function and structure at a later time.     

The heat shock cognate 80 gene of tomato is flanked by matrix attachment regions

Matrix attachment regions (MARs) are thought to participate in the organization and segregation of independent chromosomal loop domains. Although there are several reports on the action of MARs in the context of heterologous genes, information is more limited on the role of MARs associated with plant genes. Transgenic studies suggest that the upstream, intron and downstream regions of the developmentally regulated heat shock cognate 80 gene (HSC80) of tomato participate in chromatin organization. In this study, we tested the in vitro affinity of the HSC80 gene to chromosomal scaffolds prepared from shoot apices of tomato. We found that a 1.5 kb upstream region and a 1.4 kb downstream region, but not the intron region, are MARs. These MARs interact with tomato and pea scaffolds and bind regardless of the expression status of HSC80 in the tissue from which the nuclei were isolated. Comparison to two known yeast MARs ARS1 and CENIII, showed that the HSC80 5MAR binds more avidly to tomato scaffolds than ARS1, while no binding of CENIII was observed. Competition binding between the two HSC80 MARs indicated that the 5 MAR can outcompete the 3 MAR and not vice versa. Last, we observed that the interaction of the 3 MAR with the scaffold could result in an electrophoretic mobility shift resistant to SDS, protease, and phenol treatment. In conclusion, MARs whose binding properties can be clearly differentiated are closely flanking the HSC80 gene. The discovery of MARs in regions which have a distinct function in HSC80 transgenes but not in transient expression assays, is consistent with a chromosomal scaffold role in HSC80 gene regulation.     

Quantitative histochemical assay for superoxide dismutase in rat brain.

Superoxide anions are highly reactive radicals overproduced in many pathological situations such as inflammation and ischemia. One of the major factors in the protection from superoxide anions is the enzyme superoxide dismutase (SOD), which catalyzes the dismutation of superoxide to hydrogen peroxide. This study presents a quantitative histochemical method to estimate SOD activity in rat brain tissue sections. This method is based on the cerium capture method and 3,3'-diaminobenzidine amplification of transition cerium compounds. Substrate for SOD was provided by reduction of oxygen during the autoxidation of riboflavin in the presence of UV light. This histochemical method reveals the overall activity of the three different forms of SOD described in mammalian tissues: cytosolic copper-zinc SOD, mitochondrial manganese SOD, and the high molecular weight extracellular SOD. Eventually, this method can be used to quantify SOD activity in tissue sections by image analysis.     

Nucleo-cytoplasmic transport as a therapeutic target of cancer

Shuttling of specific proteins out of the nucleus is essential for the regulation of the cell cycle and proliferation of both normal and malignant tissues. Dysregulation of this fundamental process may affect many other important cellular processes such as tumor growth, inflammatory response, cell cycle, and apoptosis. It is known that XPO1 (Exportin-1/Chromosome Region Maintenance 1/CRM1) is the main mediator of nuclear export in many cell types. Nuclear proteins exported to the cytoplasm by XPO1 include the drug targets topoisomerase IIα (topo IIα) and BCR-ABL and tumor suppressor proteins such as Rb, APC, p53, p21, and p27. XPO1 can mediate cell proliferation through several pathways: (i) the sub-cellular localization of NES-containing oncogenes and tumor suppressor proteins, (ii) the control of the mitotic apparatus and chromosome segregation, and (iii) the maintenance of nuclear and chromosomal structures. The XPO1 protein is elevated in ovarian carcinoma, glioma, osteosarcoma, pancreatic and cervical cancer. There is a growing body of research indicating that XPO1 may have an important role as a prognostic marker in solid tumors. Because of this, nuclear export inhibition through XPO1 is a potential target for therapeutic intervention in many cancers. The best understood XPO1 inhibitors are the small molecule nuclear export inhibitors (NEIs; Leptomycin B and derivatives, ratjadones, PKF050-638, valtrate, ACA, CBS9106, selinexor/KPT-330, and verdinexor/KPT-335). Selinexor and verdinexor are orally bioavailable, highly potent, small molecules that are classified as Selective Inhibitors of Nuclear Export (SINE). KPT-330 is the only NEI currently in Phase I/II human clinical trials in hematological and solid cancers. Of all the potential targets in nuclear cytoplasmic transport, the nuclear export receptor XPO1 remains the best understood and most advanced therapeutic target for the treatment of cancer.     

Economic Behavior under the Influence of Alcohol: An Experiment on Time Preferences,Risk-Taking,and Altruism

We report results from an incentivized laboratory experiment undertaken with the purpose of providing controlled evidence on the causal effects of alcohol consumption on risk-taking, time preferences and altruism. Our design disentangles the pharmacological effects of alcohol intoxication from those mediated by expectations, as we compare the behavior of three groups of subjects: those who participated in an experiment with no reference to alcohol, those who were exposed to the possibility of consuming alcohol but were given a placebo and those who effectively consumed alcohol. All subjects participated in a series of economic tasks administered in the same sequence across treatments. After controlling for both the willingness to pay for an object and the potential misperception of probabilities as elicited in the experiment, we detect no effect of alcohol in depleting subjects’ risk tolerance. However, we find that alcohol intoxication increases impatience and makes subjects less altruistic.