Manipulating the bioactivity of hydroxyapatite nano-rods structured networks: Effects on mineral coating morphology and growth kinetic

Background

Nano-hydroxyapatite particles have better bioactivity than the coarse crystals. So, they can be utilized for engineered tissue implants with improved efficiency over other materials. The development of materials with specific bioactive characteristics is still under investigation.

Methods

The surface properties of four hydroxyapatite materials templated by different micelle-polymer structured network are studied. The synergistic interaction of each block copolymer in contact with CTAB rod-like micelles results in crystalline HAp nano-rods of 25–50 nm length organized in hierarchical structures with different micro-rough characteristics.

Results

It was observed that the material in vitro bioactivity strongly depends on the surface structure while in a minor extent on their Ca/P ratio. So, MIII and MIV materials with Skewness parameter R_sk > 2.62 favored the formation on their surfaces of net-like phase with a high growth kinetic constant; while MI and MII (R_sk ≤ 2.62) induced the appearance of spherulitic-like structures and a growth rate 1.75 times inferior. Material biocompatibility was confirmed by interaction with rat calvarial osteoblasts.

Conclusions

The different structures growth is attributed to a dissimilar matching of crystal planes in the material and the apatite layer formed. In specific synthesis conditions, a biocompatible material with a Ca/P ratio close to that for the trabecular bone and a morphology that are considered essential for bone-bonding was obtained.

General significance

The creation of implantable devices with a specific bioactive characteristic may be useful to manipulate the attachment of cells on mineral coating directly affecting the stability and life of the implant.     

The diagnosis of Amyotrophic lateral sclerosis in 2010

The diagnosis of Amyotrophic lateral sclerosis (ALS) remains in 2010 clinical with neurophysiological support in absence of specific biomarker(s). The disease is diverse in its presentation, cause, and progression. Treatable mimic syndromes must be excluded before the diagnosis is ascribed: ALS and its variants are recognized by neurologists, but 10% of patients are misdiagnosed. Delays in diagnosis are common. Less than 10% of cases are familial and associated with several interactive genes. The onset of ALS predates development of the clinical symptoms by an unknown interval which may extend several years. Prompt diagnosis, sensitive communication of the diagnosis, the involvement of the patient and family, a positive care plan are pre-requisites for the good clinical management of ALS patients.     

Neoadjuvant BRAF‐targeted therapy in regionally advanced and oligometastatic melanoma

Current management of locoregional and oligometastatic melanoma is typically with surgery; however, some patients are unable to undergo resection due to location/size of their tumors and/or the anticipated morbidity of the surgery. While there are currently no established guidelines for neoadjuvant therapy in melanoma, neoadjuvant BRAF‐targeted therapy may make resection more feasible. A retrospective analysis was conducted of 23 patients with BRAFV600‐mutant, stage III/IV melanoma treated with BRAF‐targeted therapy prior to surgery, with no adjuvant treatment. Surgical specimens, preoperative imaging, and clinical outcomes were evaluated. Results: Ten of 23 patients (44%) attained a pathologic complete response (pCR), with no correlation between RECIST response based on preoperative imaging and pathologic response. After a median of 43‐month follow‐up, only 1 patient (10%) with a pCR recurred, while 8 of 13 (62%) patients without a pCR recurred. Patients with a pCR had significantly improved relapse‐free (RFS) and overall survival (OS) compared to patients with residual tumor. Neoadjuvant BRAF‐targeted therapy is associated with a high pCR rate in patients with stage III‐IV melanoma, which may correlate with improved RFS and OS.     

Role of inhibitory κB kinase and c-Jun NH2-terminal kinase in the development of hepatic insulin resistance in critical illness diabetes

Hyperglycemia and insulin resistance induced by acute injuries or critical illness are associated with increased mortality and morbidity, as well as later development of type 2 diabetes. The molecular mechanisms underlying the acute onset of insulin resistance following critical illness remain poorly understood. In the present studies, the roles of serine kinases, inhibitory κB kinase (IKK) and c-Jun NH(2)-terminal kinase (JNK), in the acute development of hepatic insulin resistance were investigated. In our animal model of critical illness diabetes, activation of hepatic IKK and JNK was observed as early as 15 min, concomitant with the rapid impairment of hepatic insulin signaling and increased serine phosphorylation of insulin receptor substrate 1. Inhibition of IKKα or IKKβ, or both, by adenovirus vector-mediated expression of dominant-negative IKKα or IKKβ in liver partially restored insulin signaling. Similarly, inhibition of JNK1 kinase by expression of dominant-negative JNK1 also resulted in improved hepatic insulin signaling, indicating that IKK and JNK1 kinases contribute to critical illness-induced insulin resistance in liver.     

Ferritin as a reporter gene for in vivo tracking of stem cells by 1.5-T cardiac MRI in a rat model of myocardial infarction

The methods currently utilized to track stem cells by cardiac MRI are affected by important limitations, and new solutions are needed. We tested human ferritin heavy chain (hFTH) as a reporter gene for in vivo tracking of stem cells by cardiac MRI. Swine cardiac stem/progenitor cells were transduced with a lentiviral vector to overexpress hFTH and cultured to obtain cardiospheres (Cs). Myocardial infarction was induced in rats, and, after 45 min, the animals were subjected to intramyocardial injection of ～200 hFTH-Cs or nontransduced Cs or saline solution in the border zone. By employing clinical standard 1.5-Tesla MRI scanner and a multiecho T2* gradient echo sequence, we localized iron-accumulating tissue only in hearts treated with hFTH-Cs. This signal was detectable at 1 wk after infarction, and its size did not change significantly after 4 wk (6.33 ± 3.05 vs. 4.41 ± 4.38 mm(2)). Cs transduction did not affect their cardioreparative potential, as indicated by the significantly better preserved left ventricular global and regional function and the 36% reduction in infarct size in both groups that received Cs compared with control infarcts. Prussian blue staining confirmed the presence of differentiated, iron-accumulating cells containing mitochondria of porcine origin. Cs-derived cells displayed CD31, α-smooth muscle, and α-sarcomeric actin antigens, indicating that the differentiation into endothelial, smooth muscle and cardiac muscle lineage was not affected by ferritin overexpression. In conclusion, hFTH can be used as a MRI reporter gene to track dividing/differentiating stem cells in the beating heart, while simultaneously monitoring cardiac morpho-functional changes.     

Impaired response to influenza vaccine associated with persistent memory B cell depletion in non-Hodgkin's lymphoma patients treated with rituximab-containing regimens

Influenza vaccination is generally recommended for non-Hodgkin's lymphoma (NHL) patients, but no data are available about the activity of this vaccine after treatment with rituximab-containing regimens. We evaluated the humoral response to the trivalent seasonal influenza vaccine in a group of NHL patients in complete remission for ≥6 mo (median, 29 mo) after treatment with rituximab-containing regimens (n = 31) compared with age-matched healthy subjects (n = 34). B cell populations and incidence of influenza-like illness were also evaluated. For each viral strain, the response was significantly lower in patients compared with controls and was particularly poor in patients treated with fludarabine-based regimens. In the patient group, the response to vaccination did not fulfill the immunogenic criteria based on the European Committee for Medicinal Products for Human Use requirements. Among the patients, CD27(+) memory B cells were significantly reduced, and their reduction correlated with serum IgM levels and vaccine response. Episodes of influenza-like illness were recorded only in patients. These results showed that NHL patients treated with rituximab-containing regimens have persisting perturbations of B cell compartments and Ig synthesis and may be at particular risk for infection, even in long-standing complete remission.     

miR669a and miR669q prevent skeletal muscle differentiation in postnatal cardiac progenitors

Postnatal heart stem and progenitor cells are a potential therapeutic tool for cardiomyopathies, but little is known about the mechanisms that control cardiac differentiation. Recent work has highlighted an important role for microribonucleic acids (miRNAs) as regulators of cardiac and skeletal myogenesis. In this paper, we isolated cardiac progenitors from neonatal β-sarcoglycan (Sgcb)-null mouse hearts affected by dilated cardiomyopathy. Unexpectedly, Sgcb-null cardiac progenitors spontaneously differentiated into skeletal muscle fibers both in vitro and when transplanted into regenerating muscles or infarcted hearts. Differentiation potential correlated with the absence of expression of a novel miRNA, miR669q, and with down-regulation of miR669a. Other miRNAs are known to promote myogenesis, but only miR669a and miR669q act upstream of myogenic regulatory factors to prevent myogenesis by directly targeting the MyoD 3' untranslated region. This finding reveals an added level of complexity in the mechanism of the fate choice of mesoderm progenitors and suggests that using endogenous cardiac stem cells therapeutically will require specially tailored procedures for certain genetic diseases.     

Permeability changes induced by 130 GHz pulsed radiation on cationic liposomes loaded with carbonic anhydrase

The effects of pulsed 130 GHz radiations on lipid membrane permeability were investigated by using cationic liposomes containing dipalmitoyl phosphatidylcholine (DPPC), cholesterol, and stearylamine. Carbonic anhydrase (CA) was loaded inside the liposomes and the substrate p-nitrophenyl acetate (p-NPA) added in the bulk aqueous phase. Upon permeation across the lipid bilayer, the trapped CA catalyzes the conversion of the p-NPA molecules into products. Because the self-diffusion rate of p-NPA across intact liposomes is very low the CA reaction rate, expressed as Delta A/min, is used to track membrane permeability changes. The effect of 130 GHz radiation pulse-modulated at low frequencies of 5, 7, or 10 Hz, and at time-averaged incident intensity (I(AV)) up to 17 mW/cm(2) was studied at room temperature (22 degrees C), below the phase transition temperature of DPPC liposomes. At all the tested values of I(AV) a significant enhancement of the enzyme reaction rate in CA-loaded liposomes occurred when the pulse repetition rate was 7 Hz. Typically, an increase from Delta A/min = 0.0026 +/- 0.0010 (n = 11) to Delta A/min = 0.0045 +/- 0.0013 (n = 12) (P < 0.0005) resulted at I(AV) = 7.7 mW/cm(2). The effect of 130 GHz pulse-modulated at 7 Hz was also observed on cationic liposomes formed with palmitoyloleoyl phosphatidylcholine (POPC), at room temperature (22 degrees C), above the phase transition temperature of POPC liposomes.     

Study of the influence of ascorbyl palmitate and amiodarone in the stability of unilamellar liposomes

Amiodarone (AMI) is a low water-solubility drug, which is very useful in the treatment of severe cardiac disease. Its adverse effects are associated with toxicity in different tissues. Several antioxidants have been shown to reduce, and prevent AMI toxicity. The aim of this work was to develop and characterize Dimyristoylphosphatidylcholine (DMPC) liposomal carriers doped with ascorbyl palmitate (Asc₁₆) as antioxidant, in order to either minimize or avoid the adverse effects produced by AMI. The employment of liposomes would avoid the use of cosolvents in AMI formulations, and Asc₁₆ could minimize the adverse effects of AMI. To evaluate the partition and integration of AMI and Asc₁₆ in lipid membranes, penetration studies into DMPC monolayers were carried out. The disturbance of the liposomes membranes was studied by generalized polarization (GP). The stability of liposomes was evaluated experimentally and by means of the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory. The size particle and zeta potential (ζ) values of the liposomes were used for application in calculations for attractive and repulsive forces in DLVO theory. In experimental conditions all of these vesicles showed stability at time 0, but only DMPC?+?Asc₁₆ 10%?+?AMI 10% liposomes kept their size stable and ζ during 28 days. These results are encouraging and suggest that such systems could be suitable for AMI delivery formulations.     

Multiple Sclerosis and CCSVI: A Population-Based Case Control Study

Background

Chronic cerebrospinal venous insufficiency (CCSVI) has been associated to multiple sclerosis (MS).

Objective

To evaluate the possible association between CCSVI and MS, using a population-based control design.

Methods

A random cohort of 148 incident MS patients were enrolled in the study. We have also studied 20 patients with clinically isolated syndrome (CIS), 40 patients with other neurological diseases (OND), and 172 healthy controls. Transcranial (TCC) and Echo Color Doppler (ECD) were carried out in 380 subjects. A subject was considered CCSVI positive if ≥2 venous hemodynamic criteria were fulfilled.

Results

CCSVI was present in 28 (18.9%) of the MS patients, in 2 (10%) of CIS patients, in 11 (6.4%) of the controls, and in 2 (5%) of the OND patients. A significant association between MS and CCSVI was found with an odds ratio of 3.41 (95% confidence interval 1.63–7.13; p = 0.001). CCSVI was significantly more frequent among MS subjects with a disease duration longer than 144 months (26.1% versus 12.6% of patients with duration shorter than 144 months; p = 0.03) and among patients with secondary progressive (SP) and primary progressive (PP) forms (30.2% and 29.4, respectively) than in patients with relapsing remitting (RR) MS (14.3%). A stronger association was found considering SP and PP forms (age adjusted OR = 4.7; 95% CI 1.83–12.0, p = 0.001); the association was weaker with the RR patients (age adjusted OR = 2.58; 95%CI 1.12–5.92; p = 0.02) or not significant in CIS group (age adjusted OR = 2.04; 95%CI 0.40–10.3; p = 0.4).

Conclusions

A higher frequency of CCSVI has been found in MS patients; it was more evident in patients with advanced MS, suggesting that CCSVI could be related to MS disability.