Intravenous immunoglobulins exposed to heme (heme IVIG) are more efficient than IVIG in attenuating autoimmune diabetes

Intravenous immunoglobulins (IVIG) are known to have a therapeutic effect in some autoimmune diseases. We examined the effect of IVIG and heme-exposed IVIG on the development of immune mediated diabetes induced in C57BL/6 mice by multiple low doses of streptozotocin. IVIG were used in a dose of 200mg/kg daily for 15 days. Treatment with IVIG resulted in significant attenuation of diabetes induction as evaluated by glycemia, glycosuria and HbA1c level. Interestingly, heme-exposed IVIG had a still stronger antidiabetogenic effect. Serum levels of proinflammatory cytokines TNF-α, IFN-γ and IL17 were lower in IVIG treated animals when compared with controls, while IL10 level was higher. The number of CD4(+)Foxp3(+) cells was higher in pancreatic lymph nodes of heme-exposed IVIG treated mice. Our results show that IVIG may downregulate diabetes induction possibly by favouring induction of T regulatory cells and suggest enhanced effect upon heme-binding to IVIG.     

Solubility enhancement of desloratadine by solid dispersion in poloxamers

The present study investigates the possibility of using poloxamers as solubility and dissolution rate enhancing agents of the poorly water soluble drug substance desloratadine that can be used for the preparation of immediate release tablet formulation. Two commercially available poloxamer grades (poloxamer P 188 and poloxamer P 407) were selected, and solid dispersions (SDs) containing different weight ratio of poloxamers and desloratadine were prepared by a low temperature melting method. All SDs were subjected to basic physicochemical characterization by thermal and vibrational spectroscopy methods in order to evaluate the efficiency of poloxamers as solubility enhancers. Immediate release tablets were prepared by direct compression of powdered solid dispersions according to a General Factorial Design, in order to evaluate the statistical significance of two formulation (X(1) - type of poloxamer in SD and X(2) - poloxamer ratio in SD) and one process variable (X(3) - compression force) on the drug dissolution rate. It was found that desloratadine in SDs existed in the amorphous state, and that can be largely responsible for the enhanced intrinsic solubility, which was more pronounced in SDs containing poloxamer 188. Statistical analysis of the factorial design revealed that both investigated formulation variables exert a significant effect on the drug dissolution rate. Increased poloxamer ratio in SDs resulted in increased drug dissolution rate, with poloxamer 188 contributing to a faster dissolution rate than poloxamer 407, in accordance with the results of intrinsic dissolution tests. Moreover, there is a significant interaction between poloxamer ratio in SD and compression force. Higher poloxamer ratio in SDs and higher compression force results in a significant decrease of the drug dissolution rate, which can be attributed to the lower porosity of the tablets and more pronounced bonding between poloxamer particles.     

Elevated concentrations of retinol-binding protein-4 (RBP-4) in gestational diabetes mellitus: Negative correlation with soluble vascular cell adhesion molecule-1 (sVCAM-1)

Background. Retinol-binding protein-4 (RBP-4) may increase insulin resistance (IR) in animals, with elevated levels reported in humans with obesity and type 2 diabetes. There are, however, few data on concentrations of RBP-4 in gestational diabetes mellitus (GDM).

Methods. We measured fasting serum levels of RBP-4, soluble intercellular adhesion molecule-1 (sICAM-1) and soluble vascular cell adhesion molecule-1 (sVCAM-1) in 50 women at 28 weeks of gestation, divided according to the results of a 50 g glucose challenge test (GCT) and a 75 g oral glucose tolerance test (OGTT): (1) controls (n = 20), normal responses to both GCT and OGTT; (2) intermediate group (IG) (n = 15): false positive GCT, but normal OGTT; and (3) GDM group (n = 15), both GCT and OGTT abnormal. IR was assessed by homeostasis model assessment (HOMA-IR) and by insulin resistance index (IRI) based on glycemia and insulinemia during OGTT.

Results. All groups were matched for age and body mass index (BMI). RBP-4 levels (μg/ml, mean±standard deviation) were higher in women with GDM vs. controls (53.9 ± 17.9 vs. 29.7 ± 13.9, p ≤ 0.001), with a trend towards higher RBP-4 in GDM compared with IG (38.0 ± 19.3, p = 0.07). There was no significant correlation between RBP-4 and age, BMI, insulin, IRI or HOMA-IR, but there was a moderate, significant negative correlation between RBP-4 and sVCAM-1 (r² = 0.20, p = 0.001).

Conclusions. RBP-4 levels are elevated in women with GDM, but do not correlate with IR indices and correlate negatively with sVCAM-1. The physiological significance of RBP-4 rise in women with GDM remains to be elucidated.     

Plasma membrane phospholipid signature recruits the plant exocyst complex via the EXO70A1 subunit

Polarized exocytosis is essential for many vital processes in eukaryotic cells, where secretory vesicles are targeted to distinct plasma membrane domains characterized by their specific lipid–protein composition. Heterooctameric protein complex exocyst facilitates the vesicle tethering to a target membrane and is a principal cell polarity regulator in eukaryotes. The architecture and molecular details of plant exocyst and its membrane recruitment have remained elusive. Here, we show that the plant exocyst consists of two modules formed by SEC3–SEC5–SEC6–SEC8 and SEC10–SEC15–EXO70–EXO84 subunits, respectively, documenting the evolutionarily conserved architecture within eukaryotes. In contrast to yeast and mammals, the two modules are linked by a plant-specific SEC3–EXO70 interaction, and plant EXO70 functionally dominates over SEC3 in the exocyst recruitment to the plasma membrane. Using an interdisciplinary approach, we found that the C-terminal part of EXO70A1, the canonical EXO70 isoform in Arabidopsis, is critical for this process. In contrast to yeast and animal cells, the EXO70A1 interaction with the plasma membrane is mediated by multiple anionic phospholipids uniquely contributing to the plant plasma membrane identity. We identified several evolutionary conserved EXO70 lysine residues and experimentally proved their importance for the EXO70A1–phospholipid interactions. Collectively, our work has uncovered plant-specific features of the exocyst complex and emphasized the importance of the specific protein–lipid code for the recruitment of peripheral membrane proteins.

The plasma membrane (PM) of eukaryotic cells is spatially segregated into distinct domains with diverse functions, composition, and scales, a feature essential for many vital processes, including cell polarity regulation, signaling, and interactions with microorganisms (1, 2). Localized exocytosis is a fundamental process contributing to the establishment and maintenance of cellular polarity. An arsenal of small GTPases orchestrates the exocytosis through multiple effectors. Octameric protein complex exocyst is the small GTPase effector that facilitates the fusion of secretory vesicles with the PM (3, 4). The exocyst consists of eight subunits, Sec3, Sec5, Sec6, Sec8, Sec10, Sec15, Exo70, and Exo84, that are evolutionarily conserved across eukaryotes (5).The plant exocyst complex is crucial for targeted secretion in cellular processes including the tip growth of root hairs and pollen tubes (6–9); hypocotyl elongation (10); cell wall maturation in xylem, endodermis, and trichomes (11–13); pectin secretion in seed coats (14); recycling of PIN auxin transporters (15); and plant–microbe interactions (16, 17). The exocyst is also important for cell plate initiation and maturation during plant cytokinesis (18–20). At the outer lateral PM of plant epidermal cells, the exocyst controls the secretion of polarly localized cargo proteins (21). Notably, exocyst accumulates at the outer lateral PM in dynamic foci that are distinct from sites of endocytosis (22).While the Exo70 subunit is encoded by a single gene in yeast and animals, many EXO70 isoforms exist in angiosperm plants. Such multiplication enables the existence of diverse, functionally specific exocyst complexes even within one cell (23, 24). Particular EXO70 isoforms are involved in highly localized domain-specific secretion at the PM as documented in pollen tubes and trichomes (8, 13, 25). Some EXO70 isoforms even acquired diverged functions in autophagy regulation (26) or as negative regulators of tip growth (27, 28).In Arabidopsis, housekeeping secretory processes in most sporophytic tissues involve the EXO70 isoform EXO70A1 (29, 30). On the other hand, these processes employ the closely related EXO70A2 isoform in the male gametophyte (9). Mutant plants lacking EXO70A1, unlike other studied EXO70 mutants, are severely morphologically affected and show secretory defects similarly to several mutants in other exocyst subunits (14, 15, 29, 31, 32). Moreover, among the multiple plant EXO70 isoforms, EXO70A1 is sequentially and structurally the most similar to the yeast and animal Exo70 (24, 29, 33). Hence, we focused on the EXO70A1 function in the plant exocyst architecture and PM recruitment in this study.Molecular mechanisms of the exocyst function reside in mediating the first contact of secretory vesicles with the PM and facilitating the subsequent fusogenic SNARE complex formation, leading to a vesicle–PM fusion (34, 35). An emerging model of the exocyst complex based on partially solved structures of several exocyst subunits, protein interaction mapping, fluorescent microscopy, and cryogenic electron microscopy indicates that interlaced rod-like exocyst subunits align longitudinally at the core of the complex with distant parts being flexible and available for concomitant molecular interactions bridging vesicles and the PM (36). In yeast, the Sec15p subunit binds secretory vesicles via interaction with Rab GTPase Sec4p (37), while Sec3p and Exo70p subunits interact with the PM and serve as landmarks for the exocyst recruitment (38–40). Both Sec3p and Exo70p bind the PM-specific phosphatidylinositol 4,5-bisphosphate (PIP₂) (39–41) and protein interactors such as Rho GTPases (42, 43). In animal cells, the exocyst membrane recruitment depends on the direct interaction of Exo70 with PIP₂ (44). In yeast and animals, PIP₂-dependent recruitment represents a general mechanism governing the localization of peripheral membrane proteins to the PM (45). In contrast, other anionic phospholipids, namely phosphatidic acid (PA), phosphatidylserine (PS), and phosphatidylinositol 4-phosphate (PI4P), seem to be more important than PIP₂ in constituting the PM phospholipid signature in plants (46–48).In this study, we analyzed the overall Arabidopsis exocyst architecture and described the subunit connectivity map. Although the general architecture of the exocyst is evolutionary conserved, the PM recruitment mechanism represents a unique feature of the plant complex. By combining genetics, live-cell imaging, biochemistry, protein structure modeling, and molecular dynamics simulations, we demonstrated that the EXO70A1 subunit plays an essential role in PM–lipid signature recognition and dominates in the plant exocyst–PM recruitment to the PM.     

Systemic photochemotherapy decreases the expression of IFN-γ, IL-12p40 and IL-23p19 in psoriatic plaques

Psoriasis vulgaris (PV) is a chronic skin disease with unclear pathogenesis. In the present study we investigated the effect of systemic photochemotherapy (PUVA therapy- psoralen and UVA therapy) on the expression of IFN-γ, IL-12p40 and IL-23p19 in lesional psoriatic skin. Fifteen patients with chronic plaque type psoriasis selected to be treated with PUVA therapy were recruited for this study. Expression of IFN-γ, IL-12p40 and IL-23p19 in psoriatic lesions before and after twenty PUVA treatments was established by using immunohistochemistry (IHC). A significant decrease in expression (p?相似文献   

Hemin-catalyzed oxidative oligomerization of p-aminodiphenylamine (PADPA) in the presence of aqueous sodium dodecylbenzenesulfonate (SDBS) micelles

In a previous report on the enzymatic synthesis of the conductive emeraldine salt form of polyaniline (PANI-ES) in aqueous solution using PADPA (p-aminodiphenylamine) as monomer, horseradish peroxidase isoenzyme C (HRPC) was applied as a catalyst at pH = 4.3 with H₂O₂ as a terminal oxidant. In that work, anionic vesicles were added to the reaction mixture for (i) guiding the reaction to obtain poly(PADPA) products that resemble PANI-ES, and for (ii) preventing product precipitation (known as the “template effect”). In the work now presented, instead of native HRPC, only its prosthetic group ferric heme b (= hemin) was utilized as a catalyst, and micelles formed from SDBS (sodium dodecylbenzenesulfonate) served as templates. For the elaborated optimal reaction conditions, complementary UV/vis/NIR, EPR, and Raman spectroscopy measurements clearly showed that the reaction mixture obtained after completion of the reaction contained PANI-ES-like products as dominating species, very similar to the products formed with HRPC as catalyst. HEPES (4-(2-hydroxyethyl)-1-piperazineethanesulfonate) was found to have a positive effect on the reaction rate as compared to dihydrogenphosphate. This work is the first on the template-assisted formation of PANI-ES type products under mild, environmentally friendly conditions using hemin as a cost-effective catalyst.

Polyaniline emeraldine salt-type products were synthesized under mild, environmentally friendly conditions using hemin as a cost-effective catalyst, p-aminodiphenylamine (PADPA) as a monomer, and micelles formed from SDBS as templates.     

Computer methods for follow-up study of hemodynamic and disease progression in the stented coronary artery by fusing IVUS and X-ray angiography

Despite a lot of progress in the fields of medical imaging and modeling, problem of estimating the risk of in-stent restenosis and monitoring the progress of the therapy following stenting still remains. The principal aim of this paper was to propose architecture and implementation details of state of the art of computer methods for a follow-up study of disease progression in coronary arteries stented with bare-metal stents. The 3D reconstruction of coronary arteries was performed by fusing X-ray angiography and intravascular ultrasound (IVUS) as the most dominant modalities in interventional cardiology. The finite element simulation of plaque progression was performed by coupling the flow equations with the reaction–diffusion equation applying realistic boundary conditions at the wall. The alignment of baseline and follow-up data was performed automatically by temporal alignment of IVUS electrocardiogram-gated frames. The assessment was performed using three six-month follow-ups of right coronary artery. Simulation results were compared with the ground truth data measured by clinicians. In all three data sets, simulation results indicated the right places as critical. With the obtained difference of 5.89 ± ~4.5 % between the clinical measurements and the results of computer simulations, we showed that presented framework is suitable for tracking the progress of coronary disease, especially for comparing face-to-face results and data of the same artery from distinct time periods.     

Routine <Superscript>18</Superscript>F-FDG PET/CT does not detect inflammation in the left atrium in patients with atrial fibrillation

Increasing evidence supports a role of inflammation in the development of atrial fibrillation (AF). However, direct evidence of persistent inflammatory activity in the atria of AF patients is scarce. In this study, we used 18-Fluor-Deoxyglucose positron emission tomography computed tomography (¹⁸F-FDG PET/CT) to determine atrial inflammation in patients with and without AF. Retrospectively, ¹⁸F-FDG PET/CT scans were analyzed. 37 patients with a history of AF were compared to an age and sex matched control group with no history of AF. Standardized uptake values were obtained in the atrial walls, in the left ventricular wall, and in the right ventricular blood pool, respectively. Target to background ratios (TBR) were determined in the atrial and left ventricular walls and compared between the two groups. TBR values of the left atrial wall were slightly but not significantly higher in patients with AF (1.21?±?0.27) compared to those without AF (1.14?±?0.29; p?=?0.85). Likewise, a weak but not significant difference was observed in signal intensities in the right atrial wall between patients in the AF (1.14?±?0.45) and the control group (0.96?±?0.2; p?=?0.41). TBR values of the left ventricular myocardium did not differ between the groups; no significant correlation was found between the TBR in the left and right atrial wall and blood glucose levels. ¹⁸F-FDG PET/CT performed under routine conditions did not detect a significant difference in inflammatory activity in the left or right atrium between patients with and without AF. Contrary to previous reports, these results therefore do not clearly support a role for ongoing atrial inflammation in patients with AF. Prospective clinical studies using myocardial glucose uptake suppression strategies may be helpful to clarify these issues.     

Review of thirty patients with bone chondroblastoma

BACKGROUND/AIM: To analyse the results of the treatment of the patients with the diagnosis of chondroblastoma, to confirm the possible malignancy and to recommend the best and the safest method of the treatment. METHODS: We reviewed the cases of 30 patients with chondroblastoma who were treated between 1975 and 2004. Data were obtained using complete medical documentation, physical examinations, radiographic findings, and the available additional diagnostic procedures. RESULTS: We found that the proximal part of the tibia, proximal part of the humerus, and distal part of the femur were the most common sites of the tumor in 63% of the cases. The higher prevalence of chondroblastoma in male patients was found, especially in the second decade of life. The patients were treated with different surgical procedures after histologically confirmed chondroblastoma. In 1 of the patients, radiation therapy was performed because the lesion recurred, after which the malignant transformation of chondroblastoma occured. We found two more malignant chondroblastomas, one of which had been diagnosed as a primary tumor. Seven patients had a local recurrence, one of them had a second recurrence and the malignant transformation of chondroblastoma. The only solution was a below-knee amputation. CONCLUSION: Chondroblastoma of bone is a rare lesion with the high local recurrence rate. We emphasized the need for an adequate and rapid diagnosis, including histological verification. The treatment was strictly surgical. The basic goal of the treatment was to avoid tumor penetration into articular cavity and/or local soft tissues. Malignant chondroblastoma of bone should be treated with radical surgical resection, avoiding any adjuvant therapy.     

De novo DNA methyltransferases Dnmt3a and Dnmt3b primarily mediate the cytotoxic effect of 5-aza-2'-deoxycytidine

The deoxycytidine analog 5-aza-2'-deoxycitidine (5-aza-dC) is a potent chemotherapeutic agent effective against selective types of cancer. The molecular mechanism by which 5-aza-dC induces cancer cell death, however, is not fully understood. It has been accepted that the mechanism of toxicity is due to the covalent binding between the DNA methyltransferase (Dnmt) and 5-aza-dC-substituted DNA. In order to define which member of the Dnmt family plays a dominant role in the cytotoxicity, we examined the effect of 5-aza-dC on cell growth and apoptosis in various Dnmt null mutant embryonic stem (ES) cells. Of interest, Dnmt3a-Dnmt3b double null ES cells were highly resistant to 5-aza-dC when compared to wild type, Dnmt3a null, Dnmt3b null, or Dnmt1 null ES cells. The cellular sensitivity to 5-aza-dC correlated well with the expression status of Dnmt3 in both undifferentiated and differentiated ES cells. When exogenous Dnmt3a or Dnmt3b was expressed in double null ES cells, the sensitivity to 5-aza-dC was partially restored. These results suggest that the cytotoxic effect of 5-aza-dC may be mediated primarily through Dnmt3a and Dnmt3b de novo DNA methyltransferases. Further, the ability to form Dnmt-DNA adducts was similar in Dnmt1 and Dnmt3, and the expression level of Dnmt3 was not higher than that of Dnmt1 in ES cells. Therefore, Dnmt3-DNA adducts may be more effective for inducing apoptosis than Dnmt1-DNA adducts. These results imply a therapeutic potential of 5-aza-dC to cancers expressing Dnmt3.