Epitope evolution in poliovirus maturation

Eight monoclonal antibodies specific for native (N) poliovirus antigen all recognized empty capsids extracted from infected HeLa cells; only three of them recognized 14S particles. The facts point to the existence of two different epitopes N1 and N2, only one of which (N1) is present on 14S particles (these observations confirm and extend findings by EMINI et al). Another epitope of 14S particles is recognized by antibodies to heated (H) poliovirus antigen. Infected cell extract-catalyzed polymerization of 14S particles yielded mainly empty capsids carrying the N1 and N2, but no H epitopes.     

New Perspectives for Fixed Dose Combinations of Poorly Water-Soluble Compounds: a Case Study with Ezetimibe and Lovastatin

Purpose

Aiming to improve the dissolution rate of ezetimibe (EZE) and lovastatin (LOV) in a fixed dose combination (FDC), co-amorphous systems and ternary solid dispersions were prepared by quench cooling and spray drying, respectively.

Methods

Formulations were characterized through X-ray diffraction, modulated differential scanning calorimetry, infrared spectroscopy, scanning electron microscopy and laser diffraction, and evaluated by ‘in vitro’ dissolution. Stability studies were conducted at different conditions during 30 days with the ternary solid dispersion composed of 75% of Soluplus® (ELS 1:1 75%).

Results

Single phase co-amorphous systems made up of the pure drugs were not able to increase the dissolution rate of EZE and LOV. However, ternary solid dispersions achieved high dissolution for both compounds, especially when Soluplus® was used as carrier. The dissolution efficiency increased up to 18 (EZE) and 6 (LOV) times in ternary solid dispersions, compared to the crystalline drugs. ELS 1:1 75% preserved its amorphous state during 30 days, in different stability conditions.

Conclusions

A spray dried ternary solid dispersion able to enhance the dissolution rate of two poorly soluble, therapeutically complementary drugs, is reported for the first time. These promising results open new perspectives for the development of more advanced FDCs.

     

Adaptive mechanisms of arterial and venous coronary bypass grafts to an increase in flow demand

OBJECTIVE—To compare the mechanisms by which arterial and venous grafts increase their flow during pacing induced tachycardia, early and later after coronary bypass surgery.
DESIGN—43 grafts (13 epigastric artery, 15 mammary artery, 15 saphenous vein) evaluated early (9 (3) days (mean (SD)) after bypass surgery were compared with 41 other grafts (15 epigastric, 11 mammary, 15 saphenous vein) evaluated later after surgery (mean 23 months, range 6 to 168 months) by quantitative angiography and intravascular Doppler velocity analysis during atrial pacing. Controls were 17 normal coronary arteries.
RESULTS—Baseline graft flow tended to be lower later after surgery than early (41 (16) v 45 (21) ml/min, NS). Blood flow increased during pacing by 30 (16)% early after surgery, less than later after surgery (+46 (18)%, p < 0.001) and less than in normal coronary arteries (+54 (27)%, p < 0.001 v early grafts; NS v late grafts). There was no difference between venous and arterial grafts. No significant vasodilatation was observed during pacing early after surgery in arterial and venous grafts. Later after surgery, significant vasodilatation was observed only in arterial grafts (mammary and epigastric grafts), from 2.41 (0.37) to 2.53 (0.41) mm (+5.1% v basal, p < 0.001). Early after surgery and in venous grafts later after surgery, the increase in flow was entirely due to an increase in velocity. In later arterial grafts, the relative contribution of the increase in velocity to the increase in flow during pacing was lower in arterial grafts (70 (22)%) than in venous grafts (102 (11)%, p < 0.001) and similar to normal coronary arteries (68 (28)%).
CONCLUSIONS—Early and later after surgery, arterial grafts and venous grafts both increase their flow similarly during pacing. Early arterial grafts and venous grafts increase their flow only through an increase in velocity. Later after surgery, arterial grafts act as more physiological conduits and increase their flow in the same way as normal coronary arteries, through an increase in velocity and calibre mediated by the endothelium.


Keywords: coronary artery bypass graft; endothelial function     

Synthesis and characterization of a new carrier based on Eudragit® EPO/S100 interpolyelectrolyte complex for controlled colon-specific drug delivery

With a view to the development of peroral controlled drug delivery systems, a new interpolyelectrolyte complex (IPEC) between oppositely charged types of Eudragit?, EPO and S100, has been synthesized and investigated at neutral pH values. According to data of turbidimetry, capillary viscometry, gravimetry, and elemental analysis, the obtained IPEC has a composition of Z = [EPO]/[S100] = 1.26. Structural features of the IPEC samples have been evaluated by FTIR spectroscopy and modulated-temperature differential scanning calorimetry. The results confirmed that the IPEC is stabilized by cooperative intermacromolecular ionic bonds, is chemically homogeneous, and is characterized by a single glass transition temperature. The observed features of the carrier swelling and diclofenac sodium release from the matrix system confirm that the proposed IPEC has great potential to be used as a carrier for controlled colon-specific drug delivery.     

Overview of the mutation spectrum in familial exudative vitreoretinopathy and Norrie disease with identification of 21 novel variants in FZD4, LRP5, and NDP

Wnt signaling is a crucial component of the cell machinery orchestrating a series of physiological processes such as cell survival, proliferation, and migration. Among the plethora of roles that Wnt signaling plays, its canonical branch regulates eye organogenesis and angiogenesis. Mutations in the genes encoding the low density lipoprotein receptor protein 5 (LRP5) and frizzled 4 (FZD4), acting as coreceptors for Wnt ligands, cause familial exudative vitreoretinopathy (FEVR). Moreover, mutations in the gene encoding NDP, a ligand for these Wnt receptors, cause Norrie disease and FEVR. Both FEVR and Norrie disease share similar phenotypic characteristics, including abnormal vascularization of the peripheral retina and formation of fibrovascular masses in the eye that can lead to blindness. In this mutation update, we report 21 novel variants for FZD4, LRP5, and NDP, and discuss the putative functional consequences of missense mutations. In addition, we provide a comprehensive overview of all previously published variants in the aforementioned genes and summarize the phenotypic characteristics in mouse models carrying mutations in the orthologous genes. The increasing molecular understanding of Wnt signaling, related to ocular development and blood supply, offers more tools for accurate disease diagnosis that may be important in the development of therapeutic interventions. Hum Mutat 31:656–666, 2010. © 2010 Wiley‐Liss, Inc.     

TLR ligands and cytokines induce CXCR3 ligands in endothelial cells: enhanced CXCL9 in autoimmune arthritis

CXC chemokines are potent attractants of neutrophil granulocytes, T cells or natural killer cells. Toll-like receptors (TLR) recognize microbial components and are also activated by endogenous molecules possibly implicated in autoimmune arthritis. In contrast to CXC chemokine ligand 8 (CXCL8), no CXC chemokine receptor 3 (CXCR3) ligand (ie CXCL9, CXCL10 and CXCL11) was induced by bacterial TLR ligands in human microvascular endothelial cells (HMVEC). However, peptidoglycan (PGN), double-stranded (ds) RNA or lipopolysaccharide (LPS) (TLR2, TLR3 or TLR4 ligands, respectively) synergized with interferon-gamma (IFN-gamma) at inducing CXCL9 and CXCL10. In contrast, enhanced CXCL11 secretion was only obtained when IFN-gamma was combined with TLR3 ligand. Furthermore, flagellin, loxoribine and unmethylated CpG oligonucleotide (TLR5, TLR7 and TLR9 ligands, respectively) did not enhance IFN-gamma-dependent CXCR3 ligand production in HMVEC. In analogy with TLR ligands, tumor necrosis factor-alpha (TNF-alpha) or interleukin-1beta (IL-1beta), in combination with IFN-gamma, synergistically induced CXCL9 and CXCL11 in HMVEC and human fibroblasts, two fundamental cell types delineating the joint cavity. Etanercept, a humanized soluble recombinant p75 TNF-receptor/IgG(1)Fc fusionprotein, neutralized synergistic CXCL9 production induced by TNF-alpha plus IFN-gamma, but not synergy between IFN-gamma and the TLR ligands PGN or LPS. Synovial chemokine concentrations exemplify the physiopathological relevance of the observed in vitro chemokine production patterns. In synovial fluids of patients with spondylarthropathies (ie ankylosing spondylitis or psoriatic arthritis) or rheumatoid arthritis, significantly enhanced CXCL9, but not CXCL11 levels, were detected compared to concentrations in synovial fluids of patients with metabolic crystal-induced arthritis. Thus, CXCL9 is an important chemokine in autoimmune arthritis.     

Does bracing influence brain activity during knee movement: an fMRI study

Studies have shown that proprioceptive inputs during active and passive arm movements are processed in the primary and secondary somatosensory cortex and supplementary motor area of the brain. At which level of the central nervous system proprioceptive signals coming from the knee are regulated remains to be elucidated. In order to investigate whether there is a detectable difference in brain activity when various proprioceptive inputs are exerted at the knee, functional magnetic resonance imaging (fMRI) was used. fMRI in 13 healthy, right leg-dominant female volunteers compared brain activation during flexion–extension movements of the right knee under three different conditions: with application of a tight knee brace, with application of a moderate tight knee sleeve, and without application of a brace or sleeve. Brain activation was detected in the primary sensorimotor cortex (left and right paracentral lobule) and in the left superior parietal lobule of the brain. There was a significantly higher level of brain activation with the application of the brace and sleeve, respectively, compared to the condition without a brace or sleeve. A significantly higher cortical activation was also seen when comparing the braced condition with the condition when a sleeve was applied. The results suggest that peripheral proprioceptive input to the knee joint by means of a brace or sleeve seems to influence brain activity during knee movement. The results of this study also show that the intensity of brain activation during knee movement can be influenced by the intensity of proprioceptive stimulation at the joint.     

Symptoms and problems in the end-of-life phase of high-grade glioma patients

Despite multimodal treatment, it is not possible to cure high-grade glioma (HGG) patients. Therefore, the aim of treatment is not only to prolong life, but also to prevent deterioration of health-related quality of life as much as possible. When the patient''s condition declines and no further tumor treatment seems realistic, patients in the Netherlands are often referred to a primary care physician for end-of-life care. This end-of-life phase has not been studied adequately yet. The purpose of this study was to explore specific problems and needs experienced in the end-of-life phase of patients with HGG. We retrospectively examined the files of 55 patients who received treatment in our outpatient clinic and died between January 2005 and August 2008. The clinical nurse specialist in neuro-oncology maintained contact on a regular basis with (relatives of) HGG patients once tumor treatment for recurrence was no longer given. She systematically asked for signs and symptoms. The majority of the patients experienced loss of consciousness and difficulty with swallowing, often arising in the week before death. Seizures occurred in nearly half of the patients in the end-of-life phase and more specifically in one-third of the patients in the week before dying. Other common symptoms reported in the end-of-life phase are progressive neurological deficits, incontinence, progressive cognitive deficits, and headache. Our study demonstrates that HGG patients, unlike the general cancer population, have specific symptoms in the end-of-life phase. Further research is needed in order to develop specific palliative care guidelines for these patients.