Synthesis and characterization of self-curing hydrophilic bone cements for protein delivery

New formulations of acrylic bone cements for bone defect reparation, based on self-hardening methyl methacrylate (MMA)/methacrylic acid (MAA), with a high capacity for protein delivery, have been developed. The self-curing formulations were prepared by partial substitution of solid phase PMMA microparticles by newly obtained PMAA microspheres. The PMAA microspheres were prepared by inverse suspension polymerization of their monomer and were cross-linked with N,N'-methylene-bis-acrylamide (MBA) (10-15 wt %) to produce stable systems in contact with aqueous media. PMAA microspheres were loaded with hydrolyzed collagen (HC) as a model protein to simulate bone morphogenetic protein delivery useful for hard tissue reconstruction. Solid phase PMMA microparticles in the formulation were partially substituted by new PMAA-HC microspheres and were characterized to determine viability as an acrylic bone cement in minimally invasive surgery. The incorporation of PMAA-HC microspheres decreased peak temperature by 20°C, which minimized thermal necrotic risk after implantation. Mechanical compression tests revealed a behavior, under dry conditions, close to ISO 5833 standard requirements. However, a drastic drop in mechanical strength, ∼64%, was obtained after 15 days of immersion in simulated physiological conditions (37°C and pH 7.4) and was attributed to water absorption and a subsequent plasticizing effect. The increase in water uptake and retention enhanced the capability for controlled protein delivery. Finally, the biocompatibility of the cements was determined; some toxicity of the material during the first hours of culture incubation was observed. Later, toxicity was observed to decrease due to nonreacted monomer leaching, which ensured the low toxicity of the already polymerized phase.

[Prognostic influence of prostate gland invasion by bladder tumour and/or prostate cancer in cystoprostatectomy specimen: a review]

INTRODUCTION

Cystoprostatectomy (CPT) is the gold standard surgical treatment for muscle invasive bladder cancer (MIBC). In certain cases, MIBC can invade the prostate gland and/or a prostate cancer (PCa) can be discovered fortuitously on the pathologic specimen. The aim of the current study was to report the prognostic influence of PCa in patients who underwent a CPT for MIBC.

MATERIALS AND METHODS

A systematic review of the scientific literature was achieved in the Pubmed database, using the following keywords: prostatic neoplasm; urinary bladder neoplasm; cystectomy; surgery; recurrence; prognosis; survival. Clinical cases and series of less than five cases were deliberately excluded herein.

RESULTS

Overall, ten studies published between 2004 and 2011 and involving 2196 patients were selected. Only retrospective studies of low level of evidence (NP 4) were available. The incidence of neoplastic invasion of the prostate gland by MIBC ranged from 25 to 48%. Preoperative predictors were multiple BC, recurrent, location in the trigone and existence of CIS. Overall survival at 3 years was significantly affected by the invasion of the prostate gland (pT4a) in these patients. The incidence of PCa discovered incidentally pathologic specimen CPT ranged from 14 to 49%. Only age was found as a positive predictor. The diagnosis of PCa did not influence survival of patients with MIBC and no specific PCa adjuvant treatment was systematically advocated.

CONCLUSION

Fortuitous diagnosis of PCa and/or neoplastic invasion of the prostatic gland by BC on CPT specimen is not uncommon but this is variable across studies, depending on the quality of the pathological analysis. The invasion of the prostate gland by MIBC is a serious situation (pT4a) and linked with a poor prognosis. In case of concomitant PCa and MIBC, the prognosis is much more related to the natural history of the bladder tumour.

Platelet adhesion and human umbilical vein endothelial cell cytocompatibility of biodegradable segmented polyurethanes prepared with 4,4'-methylene bis(cyclohexyl isocyanate), poly(caprolactone) diol and butanediol or dithioerythritol as chain extenders

Biodegradable segmented polyurethanes were prepared with poly(caprolactone) diol as a soft segment, 4,4'-methylene bis(cyclohexyl isocyanate) (HMDI) and either butanediol or dithioerythritol as chain extenders. Platelet adhesion was similar in all segmented polyurethanes studied and not different from Tecoflex® although an early stage of activation was observed on biodegradable segmented polyurethane prepared with dithioerythritol. Relative viability was higher than 80% on human umbilical vein endothelial cells in contact with biodegradable segmented polyurethane extracts after 1, 2 and 7 days. Furthermore, both biodegradable segmented polyurethane materials supported human umbilical vein endothelial cell adhesion, spreading, and viability similar to Tecoflex® medical-grade polyurethane. These biodegradable segmented polyurethanes represent promising materials for cardiovascular applications.

Bioactive polymeric systems with platelet antiaggregating activity for the coating of vascular devices

The preparation, characterization, and analysis of physicochemical and biological properties of a new bioactive polymer system, based on a copolymer of an acrylic derivative of triflusal (a molecule with chemical structure related to aspirin with antiaggregating activity for platelets) is described and evaluated as thin bioactive coating for vascular grafts and coronary stents. The acrylic monomer derived from triflusal (THEMA) provides random copolymers when it is polymerized with butyl acrylate (BA), according to their reactivity ratios, r(THEMA) = 1.05 and r(BA) = 0.33. The copolymer THBA70, containing a molar composition f(THEMA) = 0.45 and f(BA) = 0.55 presents the optimal properties of stability, flexibility, and adhesion, with a T(g) = 21 ± 2 °C, to be applied as bioactive and biostable coatings for vascular grafts and coronary stents. Thin films of this copolymer system present an excellent biocompatibility and a good inherent antiaggregant activity for platelets.

Adherence to disease-modifying therapies in spanish patients with relapsing multiple sclerosis: two-year interim results of the global adherence project

The post-marketing international Global Adherence Project investigated adherence to disease-modifying therapy for relapsing-remitting multiple sclerosis. We report adherence data from the first 2 years in the Spanish subset of patients (n = 254 at baseline). The overall adherence rate was 85.4%. Patients taking intramuscular (IM) interferon-β (IFNβ)-1a were significantly more adherent (96.4%) compared with patients taking subcutaneous (SC) IFNβ-1a 22 μg (79.1%; p = 0.0064), SC IFNβ-1a 44 μg (79.6%; p = 0.0064) and glatiramer acetate (82.7%; p = 0.0184). At year 1 (n = 142), the overall adherence rate was 86.6%. Patients on IM IFNβ-1a were significantly more adherent than patients on SC IFNβ-1a 22 μg (93.9 vs. 66.7%; p = 0.0251). At year 2 (n = 131), the overall adherence rate was 82% (87.5% for IM IFNβ-1a, 80.0% for SC IFNβ-1a 22 μg, 77.8% for SC IFNβ-1a 44 μg, 85.2% for IFNβ-1b, and 80.0% for glatiramer acetate). In conclusion, adherence remained high among all disease-modifying therapies over the first 2 years of the study and was significantly higher for IM IFNβ-1a, at visit 1, compared with SC IFNβ-1a.

Biocompatibility of alendronate-loaded acrylic cement for vertebroplasty

This paper reports a biological evaluation of a non-resorbable acrylic cement loaded with alendronate for the treatment of osteoporotic vertebral compression fractures. The cement formulation was based on polymethyl methacrylate and acrylic monomers; one of these had covalently linked vitamin E residues. The same cement in the absence of alendronate was used as a control. The setting of the charged cement presented a maximum polymerization temperature of 44°C, a setting time of 24 min, a residual monomer content lower than 3 wt.%, a compressive strength of 99±10 MPa and an elastic modulus of 1.2±0.2 GPa. Cytotoxicity studies using human osteoblast cultures revealed that the leachable substances of the alendronate loaded cement collected between 1 and 7 days decreased cell viability to values lower than 80%. However, morphological changes and cellular damage in cells produced by the extracts decreased with the leak time. Cell adhesion and growth on charged cement was significantly lower than on the control. Implantation of the cement paste in the intra-femoral cavity of rabbits showed that initially the osteogenic activity was evident for the cement charged with alendronate, and the osteosynthesis process took place mainly in the trabeculae and was manifested by the presence of a non-mineralised osseous spicule. The interface between material and adjacent bone tissue was initially characterized by a variable fibrous response that in many cases it appeared reduced to thin connective tissue after a 24-week-period.

[Global adherence project to disease-modifying therapies in patients with relapsing multiple sclerosis: 2-year interim results]

BACKGROUND

In this article we report adherence data from the first 2 years in a subset of patients from the Global Adherence Project (GAP; n=2,648) in Spain.

METHODS

A questionnaire assessing adherence to Disease-modifying therapies (DMTs), was distributed annually to patients and their treating neurologists. Non-adherence was defined as missing a DMT injection or changing a dose in the four weeks prior to completing the survey. Patients signed informed consent and Ethics Committees approved annual follow-ups, visit 1 (V1) and visit 2 (V2) in 15 out of 18 centres in Spain.

RESULTS

A total of 254 patients were enrolled in Spain. Patients had a mean age of 37.9 years and 70.4% were female, and had been on their treatment for a median time of 28 months, and the overall adherence rate was 85.4%. Patients taking intramuscular interferon beta (IFNB)-1a (Avonex®) were significantly more adherent (94.6%) compared with patients taking subcutaneous (s.c.) IFNB-1a 22.g (Rebif®22) (79.1%; p=0.0064), s.c. IFNB-1a 44.g (Rebif®44) (79.6%; p=0.0064) and glatiramer acetate (GA) (82.7%; p=0.0184). At V1 (n=142), the overall adherence rate was 86.6% and patients on Avonex® were significantly more adherent than patients on Rebif®22 (93.9% versus 66.7%; p=0.0251). At V2 (n=131), the overall adherence rate was 82.4% (Avonex®, 87.5%; Rebif®22, 80%; Rebif®44, 77.8%; Betaferon®, 85.2%, and Copaxone®, 80%) without significant differences.

CONCLUSIONS

Adherence remained high over the first 2 years of the study. It was highest with Avonex®, being significant on first assessment, after 40.5 months of therapy, on average compared with other DMTs and at year 1 compared with Rebif®22.

[Long-term results of the treatment of urinary incontinence with bulbar implantation of artificial urinary sphincter in men: a single-center experience]

OBJECTIVE

To report the functional results and morbidity after implantation of bulbar artificial urinary sphincter (AUS) in incontinent men with at least 5 years of follow-up.

PATIENTS AND METHODS

The files of patients treated between 1984 and 2003 by setting up a SAU at bulbar location were reviewed. The following data were recorded: age, etiology of incontinence, intra-operative complications. To evaluate the results on continence, patients were seen at 1, 3, 6 and 12 months, and yearly thereafter.

RESULTS

Overall, 159 men implanted with an AUS were included. The median age was 68.4 years and the median follow-up was 69 months. The etiology of incontinence was a prostate surgery in 83% of cases. The five-year rates of continence and satisfaction were 74.2% (n=118) and 92% (n=140), respectively. The five-year rates of infections and erosions were 4.4% and 9.4%, respectively. In case of previous radiotherapy, the rate of erosion at 5 years was 22.2%. The rate of atrophy and urethral mechanical failure at 5 years was 7.5% and 23.6%, respectively. The rate of reoperation at 5 years was 41.5%.

CONCLUSION

Our results confirm that the AUS is still the standard treatment for male with urinary incontinence due to intrinsic sphincter deficiency. Minimally invasive therapies are being developed that could overcome the mechanical failures and offer an alternative in case of primary or even secondary failure of the AUS.

The intracarotid amobarbital or Wada test: unilateral or bilateral?

OBJECTIVE

In the Netherlands, presurgical screening for temporal lobe epilepsy (TLE) includes the intracarotid amobarbital procedure (IAP), consisting of two consecutive injections of amobarbital, ipsilateral and contralateral to the epileptic focus. We studied whether a bilateral IAP has added value to a unilateral, ipsilateral IAP.

METHODS

This population-based study included 183 consecutive patients referred for screening for TLE surgery who underwent bilateral IAP. Using multivariable modeling, we assessed the added value of bilateral IAP on the decision for surgery, resection size, amygdalohippocampectomy, post-operative seizure freedom, memory performance, and IQ change.

RESULTS

Given the results from the unilateral IAP, the bilateral IAP had added prognostic value for postoperative change in verbal memory (P < 0.01) and verbal IQ (P < 0.01), especially if patients had a left-sided focus. In contrast, information provided by the contralateral IAP was not associated with decision-making or surgical strategy.

CONCLUSIONS

A bilateral IAP has added value in predicting post-operative verbal memory and IQ. A bilateral IAP is currently not used to guide surgical strategy, but may be used for this purpose when verbal capacity is of particular concern in patients with a left-sided focus. In other cases, IAP is best performed unilaterally.

Fast and slow myosins as markers of muscle injury

Objective:

The diagnosis of muscular lesions suffered by athletes is usually made by clinical criteria combined with imaging of the lesion (ultrasonography and/or magnetic resonance) and blood tests to detect the presence of non-specific muscle markers. This study was undertaken to evaluate injury to fast and slow-twitch fibres using specific muscle markers for these fibres.

Methods:

Blood samples were obtained from 51 non-sports people and 38 sportsmen with skeletal muscle injury. Western blood analysis was performed to determine fast and slow myosin and creatine kinase (CK) levels. Skeletal muscle damage was diagnosed by physical examination, ultrasonography and magnetic resonance and biochemical markers.

Results:

The imaging tests were found to be excellent for detecting and confirming grade II and III lesions. However, grade I lesions were often unconfirmed by these techniques. Grade I lesions have higher levels of fast myosin than slow myosin with a very small increase in CK levels. Grade II and III lesions have high values of both fast and slow myosin.

Conclusions:

The evaluation of fast and slow myosin in the blood 48 h after the lesion occurs is a useful aid for the detection of type I lesions in particular, since fast myosin is an exclusive skeletal muscle marker. The correct diagnosis of grade I lesions can prevent progression of the injury in athletes undergoing continual training sessions and competitions, thus aiding sports physicians in their decision making.

The changes in the energy metabolism of human muscle induced by training

The biochemical effects of training programmes have been studied with a kinetic model of central metabolism, using enzyme activities and metabolite concentrations measured at rest and after 30 s maximum-intensity exercise, collected before and after long and short periods of training, which differed only by the duration of the rest intervals. After short periods of training the glycolytic flux at rest was three times higher than it had been before training, whereas during exercise the flux and energy consumption remained the same as before training. Long periods of training had less effect on the glycolytic flux at rest, but increased it in response to exercise, increasing the contribution of oxidative phosphorylation.