Sexual dimorphism in rabbit aortic endothelial function under acute hyperglycemic conditions and gender-specific responses to acute 17beta-estradiol

Epidemiological data suggest that hyperglycemia abrogates the gender-based cardiovascular protection possibly associated with estrogens. This study was designed to investigate 1) whether rabbit aortic rings show gender differences in the development of abnormal endothelium-dependent vasodilation (EDV) under acute hyperglycemic conditions, 2) the potential role of PKC isoforms and superoxide (O2-) in acute hyperglycemia-induced vascular dysfunction, and 3) the effect of acute estrogen administration on hyperglycemia-induced endothelial dysfunction in male and female rabbits. EDV to ACh was determined before and after 3 h of treatment with high glucose (HG) in phenylephrine-precontracted aortic rings from male and female New Zealand White rabbits. Similar experiments were conducted in the presence of inhibitors of PKC-alpha, PKC-beta, and PKC-delta or an O2- scavenger. The effect of acute estrogen administration was evaluated in the presence and absence of HG. Finally, mRNA expression of PKC isoforms was measured by real-time PCR. We found that 1) 3 h of incubation with HG impairs EDV to a greater extent in female than male aorta, 2) inhibition of PKC-beta or O2- prevents HG-induced impairment of EDV in female aorta, 3) acute 17beta-estradiol aggravates HG-induced endothelial dysfunction in female, but not male, aorta, and 4) PKC-alpha and PKC-beta expression are significantly higher in female than male aorta. This study reveals the predisposition of female rabbit aorta to vascular injury under hyperglycemic conditions, possibly via activation of PKC-beta and O2- production. Furthermore, it suggests that, under hyperglycemic conditions, acute estrogen treatment is detrimental to endothelial function in female rabbits.     

Acquisition of CD80 by human T cells at early stages of activation: functional involvement of CD80 acquisition in T cell to T cell interaction

The interaction between CD28 on T cells and CD80 on APCs intensifies the linkage between TCR and MHC at the site of contact between T cells and APCs. In this study, we demonstrate that during human T cell/human APC interaction, the autologous or allogeneic human CD4(+) T cells become positive for the detection of CD80 at an early stage of activation (24 h). This detection of CD80 is attributable to the acquisition of CD80 from APCs, as opposed to the up-regulation of endogenous CD80, as demonstrated by CD4(+) T cells treated with cyclohexamide. Furthermore, no CD80 mRNA could be detected at 24 h in T cells that had acquired CD80 from APCs. CD80 acquisition by T cells from APCs was enhanced upon TCR engagement. The amount of CD80 acquisition by CD4(+) T cells was shown to be related to the expression of CD80 on APCs. Using soluble fusion proteins (soluble CTLA-4, CD28, and CD80) to block either CD28 on the surface of T cells or CD80 on the surface of APCs, it was demonstrated that CD80 acquisition by T cells is mediated through its receptors, possibly CD28 interaction. Moreover, we demonstrate that T cells that have acquired CD80 have the ability to stimulate other T cells. These data thus suggest that CD80 acquisition by human T cells might play a role in the immunoregulation of T cell responses.     

Simple and robust methods for remote sensing of canopy chlorophyll content: a comparative analysis of hyperspectral data for different types of vegetation

Canopy chlorophyll content (CCC) is an essential ecophysiological variable for photosynthetic functioning. Remote sensing of CCC is vital for a wide range of ecological and agricultural applications. The objectives of this study were to explore simple and robust algorithms for spectral assessment of CCC. Hyperspectral datasets for six vegetation types (rice, wheat, corn, soybean, sugar beet and natural grass) acquired in four locations (Japan, France, Italy and USA) were analysed. To explore the best predictive model, spectral index approaches using the entire wavebands and multivariable regression approaches were employed. The comprehensive analysis elucidated the accuracy, linearity, sensitivity and applicability of various spectral models. Multivariable regression models using many wavebands proved inferior in applicability to different datasets. A simple model using the ratio spectral index (RSI; R815, R704) with the reflectance at 815 and 704 nm showed the highest accuracy and applicability. Simulation analysis using a physically based reflectance model suggested the biophysical soundness of the results. The model would work as a robust algorithm for canopy‐chlorophyll‐metre and/or remote sensing of CCC in ecosystem and regional scales. The predictive‐ability maps using hyperspectral data allow not only evaluation of the relative significance of wavebands in various sensors but also selection of the optimal wavelengths and effective bandwidths.     

Expanded numbers of circulating myeloid dendritic cells in patent human filarial infection reflect lower CCR1 expression

APC dysfunction has been postulated to mediate some of the parasite-specific T cell unresponsiveness seen in patent filarial infection. We have shown that live microfilariae of Brugia malayi induce caspase-dependent apoptosis in human monocyte-derived dendritic cells (DCs) in vitro. This study addresses whether apoptosis observed in vitro extends to patent filarial infections in humans and is reflected in the number of circulating myeloid DCs (mDCs; CD11c(-)CD123(lo)) in peripheral blood of infected microfilaremic individuals. Utilizing flow cytometry to identify DC subpopulations (mDCs and plasmacytoid DCs [pDCs]) based on expression of CD11c and CD123, we found a significant increase in numbers of circulating mDCs (CD11c(+)CD123(lo)) in filaria-infected individuals compared with uninfected controls from the same filaria-endemic region of Mali. Total numbers of pDCs, monocytes, and lymphocytes did not differ between the two groups. To investigate potential causes of differences in mDC numbers between the two groups, we assessed chemokine receptor expression on mDCs. Our data indicate that filaria-infected individuals had a lower percentage of circulating CCR1(+) mDCs and a higher percentage of circulating CCR5(+) mDCs and pDCs. Finally, live microfilariae of B. malayi were able to downregulate cell-surface expression of CCR1 on monocyte-derived DCs and diminish their calcium flux in response to stimulation by a CCR1 ligand. These findings suggest that microfilaria are capable of altering mDC migration through downregulation of expression of some chemokine receptors and their signaling functions. These observations have major implications for regulation of immune responses to these long-lived parasites.     

Temporal and spatial expression of osteoactivin during fracture repair

We previously identified osteoactivin (OA) as a novel secreted osteogenic factor with high expression in developing long bones and calvaria, and that stimulates osteoblast differentiation and matrix mineralization in vitro. In this study, we report on OA mRNA and protein expression in intact long bone and growth plate, and in fracture calluses collected at several time points up to 21 days post‐fracture (PF). OA mRNA and protein were highly expressed in osteoblasts localized in the metaphysis of intact tibia, and in hypertrophic chondrocytes localized in growth plate, findings assessed by in situ hybridization and immunohistochemistry, respectively. Using a rat fracture model, Northern blot analysis showed that expression of OA mRNA was significantly higher in day‐3 and day‐10 PF calluses than in intact rat femurs. Using in situ hybridization, we examined OA mRNA expression during fracture healing and found that OA was temporally regulated, with positive signals seen as early as day‐3 PF, reaching a maximal intensity at day‐10 PF, and finally declining at day‐21 PF. At day‐5 PF, which correlates with chondrogenesis, OA mRNA levels were significantly higher in the soft callus than in intact femurs. Similarly, we detected high OA protein immunoexpression throughout the reparative phase of the hard callus compared to intact femurs. Interestingly, the secreted OA protein was also detected within the newly made cartilage matrix and osteoid tissue. Taken together, these results suggest the possibility that OA plays an important role in bone formation and serves as a positive regulator of fracture healing. J. Cell. Biochem. 111: 295–309, 2010. © 2010 Wiley‐Liss, Inc.     

Right ventricular dysfunction following acute myocardial infarction in the absence of pulmonary hypertension in the mouse

Background

Cardiac remodelling after AMI is characterized by molecular and cellular mechanisms involving both the ischemic and non-ischemic myocardium. The extent of right ventricular (RV) dilatation and dysfunction and its relation to pulmonary hypertension (PH) following AMI are unknown. The aim of the current study was to evaluate changes in dimensions and function of the RV following acute myocardial infarction (AMI) involving the left ventricle (LV).

Methods

We assessed changes in RV dimensions and function 1 week following experimental AMI involving the LV free wall in 10 mice and assessed for LV and RV dimensions and function and for the presence and degree of PH.

Results

RV fractional area change and tricuspidal annular plane systolic excursion significantly declined by 33% (P = 0.021) and 28% (P = 0.001) respectively. Right ventricular systolic pressure measured invasively in the mouse was within the normal values and unchanged following AMI.

Conclusion

AMI involving the LV and sparing the RV induces a significant acute decline in RV systolic function in the absence of pulmonary hypertension in the mouse indicating that RV dysfunction developed independent of changes in RV afterload.     

Genomic characterization of some Iranian children with idiopathic mental retardation using array comparative genomic hybridization

BACKGROUND:

Mental retardation (MR) has a prevalence of 1-3% and genetic causes are present in more than 50% of patients. Chromosomal abnormalities are one of the most common genetic causes of MR and are responsible for 4-28% of mental retardation. However, the smallest loss or gain of material visible by standard cytogenetic is about 4 Mb and for smaller abnormalities, molecular cytogenetic techniques such as array comparative genomic hybridization (array CGH) should be used. It has been shown that 15-25% of idiopathic MR (IMR) has submicroscopic rearrangements detectable by array CGH. In this project, the genomic abnormalities were investigated in 32 MR patients using this technique.

MATERIALS AND METHODS:

Patients with IMR with dysmorphism were investigated in this study. Karyotype analysis, fragile X and metabolic tests were first carried out on the patients. The copy number variation was then assessed in a total of 32 patients with normal results for the mentioned tests using whole genome oligo array CGH. Multiple ligation probe amplification was carried out as a confirmation test.

RESULTS:

In total, 19% of the patients showed genomic abnormalities. This is reduced to 12.5% once the two patients with abnormal karyotypes (upon re-evaluation) are removed.

CONCLUSION:

The array CGH technique increased the detection rate of genomic imbalances in our patients by 12.5%. It is an accurate and reliable method for the determination of genomic imbalances in patients with IMR and dysmorphism.     

An intracameral injection of antigen induces in situ chemokines and cytokines required for the generation of circulating immunoregulatory monocytes

Anterior Chamber-Associated Immune Deviation (ACAID) induced by an intracameral injection of antigen generates antigen-specific regulatory splenic T cells that suppress specifically cell-mediated immunity specific for the injected antigen. Circulating F4/80(+) cells recovered from mice receiving an intracameral injection of antigen are thought to be ocular in origin and induce the development of thymic and splenic regulatory T cells. We have shown previously that after the intracameral injection of antigen there is a CCR2/CCL2-dependent infiltration of circulating F4/80(+) cells into the anterior chamber associated with the generation of circulating, ACAID-inducing F4/80(+) monocytes. Here we tested the hypothesis that the intracameral injection of antigen induces events in the anterior chamber that are associated with the induction of circulating immunoregulatory monocytes that induce the suppression of cell-mediated immunity. The intracameral injection of antigen resulted in aqueous humor (i) a time- dependent increase of CCL2 and CCL7, (ii) a transient increase in TNF-α, and (iii) an infiltration of CD11b(hi), Gr1(hi) and F4/80(+) as well as F4/80(-) and Gr1(hi) peripheral blood cells into the anterior chamber. Further characterization of these F4/80(+) cells revealed that they are Ly 6C(hi), LY6G(lo) or negative, 7/4 (LY6B)(hi), CD115(+), CD45(+), CD49B(+), and CD62 L(+). Antibody-mediated neutralization of TGF-β in situ in the anterior chamber prevented the induction of circulating, ACAID-inducing monocytes and ACAID. These cells did not increase in the irides of ACAID-refractory CCR2-/- and CCL2-/- mice that received an intracameral injection of antigen. Our results extend our suggestion that ACAID is initiated as the result of a mild proinflammatory response to intracameral injection that results in the infiltration of a CCR2(+) subset of monocytes into the anterior chamber where there is a TGF-β-dependent induction of an immunosuppressive phenotype in the infiltrated monocytes that recirculate to induce antigen-specific regulatory T cells.