The influence of exon 7 Phe389Leu polymorphism on P120 catenin interactions with E-cadherin and three-dimensional model rebuilt

The significance of endothelial P120 catenin (P120ctn) activity has been recognized for many years, however it was only recently that the complicated regulation of this constitutively expressed enzyme in endothelial cells was identified. A critical component of the P120ctn regulatory cycle in endothelial cells is its intracellular localization to caveolae. The caveolar coordination of P120ctn, more specifically its interaction with E-cadherin plays a major role in normal endothelial P120ctn activity and vascular bioavailability of nitric oxide. We have recently shown that the presence of P120ctn exon 7 Phe389Leu polymorphism caused diminished shear which was dependent catenin activation, was less extensively associated with caveolae, and had a decreased degree of interaction with E-cadherin. Here, we carried out preliminary investigations to identify possible mechanisms of the genotype-dependent endothelial cell responses we observed in our previous investigations. Through this approach we tested the hypothesis that computer simulations could provide insights regarding the contribution of this single nucleotide polymorphism to regulation of the P120ctn isoform. We observed that in the Phe/Leu and Leu/Leu mutant genotypes, the amount of P120ctn associated with E-cadherin was significantly lower. Additionally, we have shown, using a theoretical computational model, that mutation of an amino acid at position 389 might affect the protein-protein interactions and localization of the P120ctn protein. These alterations might also affect the protein function and explain the enhanced disease risk associated with the presence of Phe389Leu polymorphism in the P120ctn protein.

Effect of soft segment crystallization and hard segment physical crosslink on shape memory function in antibacterial segmented polyurethane ionomers

Shape memory polyurethane (SMPU) ionomers containing constant 75 wt.% soft segment content were synthesized using poly(epsilon-caprolactone)diol, 4,4'-diphenylmethane diisocyanate, 1,4-butanediol and/or N,N-bis(2-hydroxyethyl)-isonicotinamide. To introduce substrate bonding antibacterial activity, pyridinium was prepared through a neutralization reaction using 1-iodooctane as neutralization agent. For the SMPU ionomer film obtained, tensile testing at 70 degrees C and dynamic mechanical analysis suggests that, at temperatures>T(ms) (the melting point of soft segments), 6.72 and 29.55 mol.% pyridinium within hard segments significantly decreased the mechanical properties such as the stress at 100% elongation (70 degrees C), the initial modulus (70 degrees C) and the elastic modulus (75-110 degrees C). Cyclic tensile investigation demonstrated that the two factors, soft segment crystallization and hard segment physical crosslink, play a very important role in shape memory function in SMPU ionomers. For the each individual specimen, the fixity ratio increased, and the recovery ratio decreased with the extension of cooling time. After sufficient cooling time, the fixity ratio of all specimens can reach a high value (approximately 95%). Owing to the disrupted physical crosslink in the sample containing 29.55 mol.% pyridinium, the crystallization rate of soft segments has less effect on shape fixity. Therefore, a high fixity ratio (93.8%) can be achieved in a short cooling time (30 s). In the control sample, the fixity ratio is only 73.7% after 30 s cooling. In addition, the admirable substrate bonding antibacterial activity of prepared SMPU ionomers was verified using standards AACTT 147 and ASTM E2149 in comparison with the control sample. The antibacterial activity of SMPU ionomers on Gram-positive bacteria (Staphylococcus aureus) is significant, and the rate of reduction of bacteria is 100%; the antibacterial activity on Gram-negative bacteria (Klebsiella pneumoniae) increases from 83.6% to 90.7% with increase in pyridinium content from 6.72 to 29.55 mol.%.

Risk behaviours in HIV-positive men who have sex with men participating in an intervention in a primary care setting

Men who have sex with men receiving HIV care reported their sexual behaviours and their intentions, classified according to the Transtheoretical Model of Change, to modify the following behaviours: (1) condom use by partner type and activity type; (2) reduction of partner number; and (3) disclosure of HIV serostatus to partners. Most participants were white (68.8%) or black (29.5%) and were more likely to report unprotected sex with HIV-positive than with serodiscordant partners for most activities. Whites reported more partners than black patients (mean 4.1 versus 2; P < 0.0001) and black participants reported fewer HIV-negative (P = 0.0084) and -unknown status partners (P = 0.00095) than whites. Cocaine/crack use was associated with more sexual partners (P = 0.001) and more frequent unprotected sex with HIV-negative or -unknown status partners (P = 0.036). Readiness to change risk behaviour varied by partner status and type of sexual activity. Understanding patients' risks and their readiness to change behaviours may help providers to promote sexual health.

Regional hypoxia correlates with the uptake of a radiolabeled targeted marker of angiogenesis in rat model of myocardial hypertrophy and ischemic injury

BACKGROUND

Non-invasive imaging strategies play a critical role for assessment of the efficacy of angiogenesis therapies. Hypoxia resulting from deficient blood flow is a potent stimulator of angiogenesis which is marked by upregulated alphavbeta3 integrin receptor.

METHODS AND RESULTS

The use of dual-isotope radiotracers targeted at alphavbeta3 and myocardial hypoxia has been demonstrated to non-invasively track hypoxia-induced angiogenesis in ischemic rat model of myocardial hypertrophy, which was induced by non-occlusive abdominal aortic banding followed by myocardial infarction at 6 weeks after the banding procedure. The pressure overload-induced myocardial hypertrophy was confirmed by 2D echocardiography. Two radiotracers; 111In-labeled agent targeted at the alphavbeta3 (RP748) and 99mTc-labeled nitroimidazole retained in hypoxic myocardium (BRU-5921) have been used. Gamma well counting analysis demonstrated an inverse linear relationship (R2=0.5) between BRU-5921 myocardial uptake and the degree of hypoperfusion assessed by 201Tl chloride. 111In-RP748 was found to be preferentially retained in hypoxic myocardium identified by increased BRU-5921 uptake and localized to anterior-lateral wall as assessed by dual-isotope microautoradiography. There was a significant (P<0.01) almost four-fold increase in RP748 uptake in myocardial segments with highest relative BRU-5921 retention (200-600% non-ischemic). Immunohistochemical staining confirmed that increased RP748 uptake is associated with an augmented alphav and beta3 integrin expression within infarcted myocardium.

CONCLUSIONS

Angiogenesis in the rodent model of combined myocardial hypertrophy and infarction was successfully assessed with alphavbeta3-targeted agent in relation to tissue hypoxia measured with 99mTc -labeled nitroimidazole retained in hypoxic myocardium. Regional retention of RP748 correlated well with BRU-5921 retention, supporting the role of RP748 as a targeted marker of hypoxia-stimulated angiogenesis with a potential clinical use to track naturally occurring and therapeutic angiogenesis and to predict the left ventricular remodeling in patients following myocardial infarction.

Poly-GLP-1, a novel long-lasting glucagon-like peptide-1 polymer, ameliorates hyperglycaemia by improving insulin sensitivity and increasing pancreatic beta-cell proliferation

AIM

The clinical value of glucagon-like peptide-1 (GLP-1) is restricted because of its short half-life. To overcome this limitation, a new polymer of GLP-1 was developed by prodrug strategy, termed Poly-GLP-1, and its pharmacological properties were investigated.

METHODS

The in vitro release kinetics of GLP-1 from Poly-GLP-1 was analysed by Western blot. Plasma GLP-1 levels following a single administration of Poly-GLP-1 were determined by enzyme-linked immunosorbent assay. The in vitro effects of Poly-GLP-1 were evaluated using isolated pancreatic islets. The acute effects on glycaemic control and food intake were investigated in C57BL/6J mice s.c. administered with Poly-GLP-1. The chronic effects of Poly-GLP-1 on glycaemic control were further assessed in C57BL/6J and db/db mice treated twice daily for 6 weeks.

RESULTS

Pro-GLP-1 dose dependently increased insulin secretion and decreased glucose, but did not exhibit the insulinotropic action in isolated pancreatic islets without plasma. The glucose-lowering actions of Poly-GLP-1 (3 nmol/kg) remained no less than 12 h after a single injection. Poly-GLP-1 caused a durable restoration of glycaemic control, food intake and body weight gain in db/db mice following 6-week administration. The chronic treatment with Poly-GLP-1 improved glucose tolerance and insulin sensitivity and increased beta-cell mass and proliferation in db/db mice. There was little effect on normal mice treated in the same manner.

CONCLUSIONS

Our results indicated that Poly-GLP-1, a novel GLP-1 polymer, has long-lasting and potent effects on glycaemic control in vivo, and these beneficial effects may be because of improvement of insulin sensitivity and promotion of islet growth and function.

Tolerant T cells inhibit natural killer cells function in antigen-presenting cells in an independent fashion

Understanding the relationships among immune cells in the setting of immunologic tolerance is imperative to maintain organ and tissue transplants. T cells and natural killer (NK) cells are responsible for both immune tolerance and immune rejection; however, there is only limited knowledge about the relevance of T and NK cells in tolerance. To address this issue, we explored the possible actions of tolerant T cells on NK cells by the means of mixed lymphocyte co-cultures and NK cytotoxicity assays. We showed that tolerant T cell-induced blockade of the co-stimulatory pathway significantly inhibited NK cell function in vitro regarding antigen-presenting cells. This action was cell-cell-contact dependent. We argue that tolerant T cells and NK cells impart synergistic cooperation to maintain transplant tolerance.

Characterization of Lin'an montmorillonite and its application in the removal of Ni2+ from aqueous solutions

Clay minerals have been studied extensively because of their strong sorption and complexation ability. In this work, Na-montmorillonite was characterized by using acid-base titration, XRD and FTIR in detail. Sorption of Ni(II) on Na-montmorillonite was investigated under ambient conditions as a function of pH, ionic strength, and temperature. The results indicate that sorption of Ni2+ on montmorillonite are strongly dependent on pH and ionic strength. The sorption of Ni2+ is mainly dominated by ion exchange at low pH values and by inner-sphere surface complexation at high pH values. The relationships of pH–C eq, Q–C eq and pH–Q are compared and shown clearly in a 3-D plot, and all Q–C eq data lie in a straight line with slope (−V/m) and intercept (C 0 V/m). The thermodynamic parameters (ΔH°, ΔS°, and ΔG°) are calculated from the temperature dependent sorption isotherms, and the results suggest that the sorption reaction of Ni(II) from solution to montmorillonite is endothermic and spontaneous.

OsEF3, a homologous gene of Arabidopsis ELF3, has pleiotropic effects in rice

Heading date is an important agronomic trait in rice. A rice mutant with a late heading date and no photoperiodic sensitivity in long or short day conditions was obtained from rice T-DNA insertion mutants in Zhonghua11 (ZH11). Through isolation and analysis of the flanking sequence of the T-NDA insertion site, the target sequence of insertion was obtained and found to locate in AP003296, the sequence accession number of rice chromosome 1 of RGP (http://rgp.dna.affrc.go.jp). The putative amino acid sequences of this target gene are homologous to the Arabidopsis protein ELF3 encoded by an early flowering gene. The rice target gene orthologous to Arabidopsis ELF3 is named OsEF3; this encodes a putative nematode responsive protein-like protein. OsEF3 has pleiotropic effects in rice that differ from the effects of Arabidopsis ELF3, which only affects biological rhythms. OsEF3 regulates heading date by influencing the BVG stage and does not affect photoperiodic sensitivity, which suggests that the OsEF3 gene may be involved in an autonomous pathway in rice. OsEF3 may affect root development and kilo-grain weight by delaying cell division or cell elongation.

Unique structure and property of cyclodextrins and their application in transdermal drug delivery

Owing to their bioadaptability and multifunctional characteristics, cyclodextrins have been shown to be useful in drug delivery systems. This article presents the unique structure and properties and the current application of natural and chemically modified cyclodextrins in transdermal drug delivery systems, focusing on their ability to enhance the solubility and stability of drug molecules and to improve drug absorption across biological barriers.

Prospective comparison of 3D FIESTA versus fat-suppressed 3D SPGR MRI in evaluating knee cartilage lesions

AIM

To prospectively compare the accuracy of three-dimensional fast imaging employing steady-state acquisition (3D FIESTA) sequences with that of fat-suppressed three-dimensional spoiled gradient-recalled (3D SPGR) in the diagnosis of knee articular cartilage lesions, using arthroscopy as the reference standard.

MATERIALS AND METHODS

Fifty-eight knees in 54 patients (age range 21-82 years; mean 36 years) were prospectively evaluated by using sagittal 3D FIESTA and sagittal fat-suppressed 3D SPGR sequences. Articular cartilage lesions were graded on MRI and during arthroscopy with a modified Noyes scoring system. Sensitivity, specificity, and accuracy were assessed. Interobserver agreement was determined with kappa statistics.

RESULTS

The performance of 3D FIESTA sequences (sensitivity, specificity, and accuracy were 80, 94, and 92%, respectively, for reader 1 and 76, 94, and 90%, respectively, for reader 2) was similar to that of fat-suppressed 3D SPGR sequences (sensitivity, specificity, and accuracy were 82, 92, and 90%, respectively, for reader 1 and 82, 90, and 88%, respectively, for reader 2) in the detection of knee articular cartilage lesions. The interobserver agreement varied from fair to good to excellent (kappa values from 0.43-0.83).

CONCLUSION

3D FIESTA has good diagnostic performance, comparable with fat-suppressed 3D SPGR in evaluating knee cartilage lesions, and it can be incorporated into routine knee MRI protocols due to the short acquisition time.

Spatiotemporal evolution of Poiseuille-Rayleigh-Bénard flows in binary fluids with Soret effect under initial pulselike disturbances

The spatiotemporal evolution of Poiseuille-Rayleigh-Bénard flows in binary fluids with Soret effect is investigated by carrying out fully nonlinear two-dimensional numerical simulations initiated by a pulselike disturbance. The traveling wave packets for positive as well as negative separation factors psi are obtained numerically for ethanol-water-like mixtures (Prandtl number Pr=10 , Lewis number Le=0.01) and selected combinations of Rayleigh and Reynolds numbers at psi=0.01, 0.1 and psi=-0.1. The characteristics of the wave fronts and the transitions observed between absolute and convective instabilities when changing the parameters are compared with the results previously obtained by linear spatiotemporal stability analysis. The simulations are in very good agreement with the stability results, which confirms the validity of both approaches. Finally, in order to characterize the possible interaction between the two wave packets of the so-called downstream and upstream modes for psi<0, the spatiotemporal stability analysis is used to detect a boundary curve in the (Re, Ra) parameter region beyond which the two wave packets will never completely separate. Numerical simulations illustrate the different evolutions of the wave packets on both sides of this boundary.

Class I topical corticosteroid use by psoriasis patients in an academic practice

BACKGROUND

Psoriasis is a chronic skin disorder that can have a profound impact on the quality of life of patients. The treatment of psoriasis is complicated by the availability of numerous topical agents, systemic agents, and phototherapy. Of the topical preparations available, the ultra-high potency, or Class I steroids, have an important role in treating psoriasis. Their use is most appropriate for the treatment of plaques in regions excluding the face, axilla, groin and genitals.

OBJECTIVE

The purpose of this study was to examine the prescribing patterns of Class I topical corticosteroids within a large academic dermatology practice for patients with all types of psoriasis.

METHODS

A retrospective chart review of 650 patients with psoriasis from an academic dermatology practice was performed. Class I steroid use was defined as those patients who were observed to be currently using clobetasol propionate, halobetasol propionate, diflorasone, or augmented betamethasone dipropionate.

RESULTS

A total of 79% of patients were prescribed topical steroids of any class while 46% of patients were prescribed a Class I steroid. In all, 58% of patients who received topical steroid therapy received a Class I agent; 11% of patients prescribed Class I steroids also received systemic therapy for their psoriasis. Conversely, 35% of patients who received systemic therapy were also receiving Class I topical therapy.

DISCUSSION

In our department, Class I topical steroids are commonly used in the treatment of psoriasis. The superpotent topicals are often used as an adjunct to systemic therapy and will likely remain a mainstay of psoriasis therapy.

Gender differences in pulmonary regenerative response to naphthalene-induced bronchiolar epithelial cell injury

OBJECTIVES

Accumulating evidence suggests that gender affects the incidence and severity of several pulmonary diseases. Previous studies on mice have shown gender differences in susceptibility to naphthalene-induced lung injury, where Clara cell damage was found to occur earlier and to be more extensive in females than in males. However, very little is known about whether there are any gender differences in subsequent lung repair responses. The aim of this study was to investigate whether gender plays an important role in pulmonary regenerative response to naphthalene-induced Clara cell ablation.

MATERIALS AND METHODS

Adult male and female mice were injected with a low, medium, or high dose of naphthalene, and lung tissue regeneration was examined by immunohistochemical staining for cell proliferation marker (Ki-67) and mitosis marker (phosphohistone-3).

RESULTS

Histopathological analysis showed that naphthalene-induced Clara cell necrosis was more prominent in the lungs of female mice as compared to male mice. Cell proliferation and mitosis in both the distal bronchiolar airway epithelium and peribronchiolar interstitium of female mice was significantly greater than that of male mice after treatment with the low and medium doses. However, after treatment with high dose of naphthalene, lung regeneration was delayed in female mice, while male mice mounted a timely regenerative response.

CONCLUSIONS

These findings show that there are clear gender differences in naphthalene-induced lung injury and repair.

Combination of beta-TCP and BMP-2 gene-modified bMSCs to heal critical size mandibular defects in rats

OBJECTIVE

To investigate the effects of mandibular defects repaired by a tissue engineered bone complex with beta-tricalcium phosphate (beta-TCP) and bone morphogenic protein-2 (BMP-2) gene-modified bone marrow stromal cells (bMSCs).

MATERIALS AND METHODS

bMSCs derived from Fisher 344 rats were cultured and transduced with adenovirus AdBMP-2, AdEGFP gene in vitro. Osteogenic differentiation of bMSCs was determined by alkaline phosphatase staining, von Kossa assay and reverse transcription-polymerase chain reaction. Gene transduced or untransduced bMSCs were seeded on beta-TCP scaffolds to repair mandibular full thickness defects with a diameter of 5 mm. Eight weeks post-operation, X-ray examination, micro-computerized tomography and histological and histomorphological analysis were used to evaluate the bone healing effects.

RESULTS

Alkaline phosphatase staining and mineralized nodules formation were more pronounced in AdBMP-2 group 14 days after gene transduction when compared with that of AdEGFP or untransduced group. The mRNA expression of osteopontin and osteocalcin also significantly increased 9 days after AdBMP-2 gene transduction. Mandibular defects were successfully repaired with AdBMP-2-transduced bMSCs/beta-TCP constructs. The percentage of new bone formation in AdBMP-2 group was significantly higher than that of other control groups.

CONCLUSIONS

Bone morphogenic protein-2 regional gene therapy together with beta-TCP scaffold could be used to promote mandibular repairing and bone regeneration.

Myosin-II negatively regulates minor process extension and the temporal development of neuronal polarity

The earliest stage in the development of neuronal polarity is characterized by extension of undifferentiated "minor processes" (MPs), which subsequently differentiate into the axon and dendrites. We investigated the role of the myosin II motor protein in MP extension using forebrain and hippocampal neuron cultures. Chronic treatment of neurons with the myosin II ATPase inhibitor blebbistatin increased MP length, which was also seen in myosin IIB knockouts. Through live-cell imaging, we demonstrate that myosin II inhibition triggers rapid minor process extension to a maximum length range. Myosin II activity is determined by phosphorylation of its regulatory light chains (rMLC) and mediated by myosin light chain kinase (MLCK) or RhoA-kinase (ROCK). Pharmacological inhibition of MLCK or ROCK increased MP length moderately, with combined inhibition of these kinases resulting in an additive increase in MP length similar to the effect of direct inhibition of myosin II. Selective inhibition of RhoA signaling upstream of ROCK, with cell-permeable C3 transferase, increased both the length and number of MPs. To determine whether myosin II affected development of neuronal polarity, MP differentiation was examined in cultures treated with direct or indirect myosin II inhibitors. Significantly, inhibition of myosin II, MLCK, or ROCK accelerated the development of neuronal polarity. Increased myosin II activity, through constitutively active MLCK or RhoA, decreased both the length and number of MPs and, consequently, delayed or abolished the development of neuronal polarity. Together, these data indicate that myosin II negatively regulates MP extension, and the developmental time course for axonogenesis.