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1.
Genome Announc ; 1(1)2013 Jan.
Article in English | MEDLINE | ID: mdl-23405342

ABSTRACT

Here, we describe the genome sequence of the Francisella tularensis subsp. holarctica strain F92, belonging to the Franco-Iberian subgroup. This strain represents the first-time isolate of this subgroup in Germany and was obtained from naturally infected marmosets.

2.
Rheumatol Int ; 33(3): 637-43, 2013 Mar.
Article in English | MEDLINE | ID: mdl-22527138

ABSTRACT

Due to pleiotropic-synergistic actions on bone, muscle, gut, brain and different other non-skeletal tissues, alfacalcidol is an interesting drug for treating osteoporosis. In studies on glucocorticoid-induced osteoporosis, men have always been treated with calcitriol or this active D-hormone prodrug, but there is no study of male patients only in the literature. The AIM-Trial (Alfacalcidol In Men) is an extension of the control group (n = 158) of our former risedronate study in male osteoporosis (Ringe et al. in Rheumatol Int 29:311-315, 2009). In that study, we treated daily those controls with prevalent vertebral fractures with 1 µg alfacalcidol + 500 mg calcium (group A) and those without prevalent vertebral fractures with 1,000 IU plain vitamin D (Vit. D) + 1,000 mg calcium (group B). Subsequently, we added an additional 56 pairs of patients to these two groups: 28 with and 28 without prevalent vertebral fractures, reaching a total of 214 cases. That means with this design, we are comparing two groups with a different risk at onset. Due to the prevalent vertebral fractures and lower average bone mineral density (BMD) values, there was a higher risk of incident fractures in group A. After 2 years, we found significantly higher increases in lumbar spine BMD (+3.2 vs. +0.8 %) and total hip BMD (+1.9 vs. -0.9 %) in group A and B, respectively. Eighteen incident falls were recorded in the alfacalcidol group and 38 in the group treated with Vit. D (p = 0.041). There were significantly lower rates of patients with new vertebral and non-vertebral fractures in group A than in group B. Back pain was significantly reduced only with alfacalcidol. Concerning the incidence of new non-vertebral fractures, we found that there was a relation to renal function in the two groups. The advantage for alfacalcidol was mainly due to a higher non-vertebral fracture-reducing potency in patients with a creatinine clearance (CrCl) below 60 ml/min (p = 0.0019). There were no serious adverse events (SAE), and the numbers of mild-to-moderate adverse events (AE) were not different between groups. Despite the higher initial fracture risk in the alfacalcidol group, 2-year treatment with this active D-hormone prodrug showed a higher therapeutic efficacy in terms of BMD, falls and fractures. One important advantage of alfacalcidol may be that it is effective even in patients with mild-to-moderate renal insufficiency.


Subject(s)
Bone Density Conservation Agents/therapeutic use , Hydroxycholecalciferols/therapeutic use , Osteoporosis/drug therapy , Aged , Bone Density/drug effects , Endpoint Determination , Humans , Hydroxycholecalciferols/adverse effects , Kidney/drug effects , Male , Middle Aged , Prospective Studies , Vitamin D/administration & dosage
3.
Rheumatol Int ; 32(1): 207-15, 2012 Jan.
Article in English | MEDLINE | ID: mdl-20827552

ABSTRACT

We investigated the effect of daily therapy with 1 mcg alfacalcidol (Doss(®)-TEVA/AWD-pharma) on muscle power, muscle function, balance performance and fear of falls in an open, multi-centered, uncontrolled, prospective study on a cohort of patients with reduced bone mass. Among the 2,097 participants, 87.1% were post-menopausal women and 12.9% were men. Mean age was 74.8 years and mean body mass index (BMI) 26.3 kg/m². A total of 75.3% of the study population had osteoporosis, 81% a diagnosis of "increased risk of falls" and 70.1% had a creatinine clearance (CrCl) of <65 ml/min. Participants underwent muscle function and muscle power tests at onset and after 3 and 6 months: the timed up and go test (TUG) and the chair rising test (CRT). At baseline and after 6 months, participants performed the tandem gait test (TGT) and filled out a questionnaire evaluating fear of falling. Successful performance in the muscle tests is associated with a significantly lower risk of falls and non-vertebral fractures in elderly patients (successful test performance: TUG ≤ 10 s (sec), CRT ≤ 10 s, TGT ≥ 8 steps). A significant improvement in the performance of the two muscle tests was proved already after 3 months of treatment with alfacalcidol and further increased by the end of the therapeutic intervention. There were significant increases in the number of participants able to successfully perform the tests: 24.6% at baseline and 46.3% at the end of trial for the TUG (P < 0.0001) and 21.7% at baseline and 44.2% at the end for the CRT test (P = 0.0001). The mean time used for the TUG was decreased by 3.0 s from the average onset value of 17.0 s and by 3.1 s from the initial average 16.5 s for the CRT. The percentage of participants able to perform the balance test (TGT) increased from 36.0% at onset to 58.6% at the end of the trial (P < 0.0001). An increased fear of falling was reduced by the end of the study in 74.4% of the patients. Throughout the study, there were 26 adverse drug reactions in 11 out of 2,097 patients (incidence 0.52%). No serious adverse drug reactions and no cases of hypercalcemia were documented. We conclude that treatment with alfacalcidol is safe, increases muscle power, muscle function and balance and reduces fear of falls. The significant improvement in the three muscle and balance tests and fear of falls may have a preventative effect on falls and fractures. We suggest that the quantitative risk tests used in this study could be reliable surrogate parameters for the risk of falls and fractures in elderly patients.


Subject(s)
Bone Density Conservation Agents/therapeutic use , Bone Density/drug effects , Hydroxycholecalciferols/therapeutic use , Muscle Strength/drug effects , Muscle, Skeletal/physiology , Osteoporosis/drug therapy , Osteoporosis/physiopathology , Postural Balance/drug effects , Accidental Falls/prevention & control , Aged , Aged, 80 and over , Bone Density/physiology , Bone Density Conservation Agents/adverse effects , Bone Density Conservation Agents/pharmacology , Cohort Studies , Dose-Response Relationship, Drug , Fear/psychology , Female , Humans , Hydroxycholecalciferols/adverse effects , Hydroxycholecalciferols/pharmacology , Male , Muscle Strength/physiology , Muscle, Skeletal/drug effects , Osteoporosis/psychology , Postural Balance/physiology , Prospective Studies , Retrospective Studies , Risk Factors , Surveys and Questionnaires , Treatment Outcome
4.
MMW Fortschr Med ; 154 Suppl 1: 10-21, 2012 Apr 05.
Article in German | MEDLINE | ID: mdl-23427364

ABSTRACT

BACKGROUND: The therapeutic strategy for the reduction of fracture risk in osteoporosis should not only aim to increase bone strength, but should also improve muscle function and reduce falls without increasing the risk of significant side effects. Since 2008 a combination therapy of the antiresorptive active bisphosphonatealendronate and the pleiotropic active D-hormone-prodrug alfacalcidol is licensed in Germanyfor treatment of postmenopausal osteoporosis (Tevabone). METHODS: In the review the results of numerous preclinical and clinical studies are reported, showing the efficacy of the combination of alendronate plus alfacalcidol. RESULTS: In preclinical trials with ovariectomized rats the combination has shown a significantly better effect on increased bone turnover in comparison with bisphosphonate monotherapy. Presumably the "oversuppression" of bone remodeling and the resulting risk of reduced microfracture healing, which is known to occur after long-term therapy with bisphosphonates, will be reduced by the combination. Clinical studies have shown better efficacy of the combination in the increase of bone density and reduction of fracture rate (vertebral and non-vertebral fractures). Less falls were reported compared to alendronate plus genuine vitamin D. The reduction of increased parathormone levels by the alendronate plus alfacalcidol combination compared to alendronate alone was proven to increase the responder rate of the alendronate therapy. The potential risks of alendronate-induced hypocalcemia as well as alfacalcidol-induced hypercalcemia or hypercalcuria are reduced due to the contrasting mode of action of both compounds. CONCLUSION: Treatment with the alendronate plus alfacalcidol combination meets the demands of an optimized therapy for osteoporosis.With the especially developed, self-explanatory combination package better compliance and less dispensing mistakes can be expected.


Subject(s)
Alendronate/administration & dosage , Evidence-Based Medicine , Hydroxycholecalciferols/administration & dosage , Osteoporosis, Postmenopausal/drug therapy , Aged , Alendronate/adverse effects , Animals , Bone Density/drug effects , Disease Models, Animal , Drug Combinations , Drug Interactions , Etidronic Acid/administration & dosage , Etidronic Acid/adverse effects , Etidronic Acid/analogs & derivatives , Female , Humans , Hydroxycholecalciferols/adverse effects , Long-Term Care , Middle Aged , Osteoporosis, Postmenopausal/diagnosis , Osteoporotic Fractures/diagnosis , Osteoporotic Fractures/prevention & control , Randomized Controlled Trials as Topic , Rats , Risedronic Acid
5.
J Musculoskelet Neuronal Interact ; 11(1): 34-45, 2011 Mar.
Article in English | MEDLINE | ID: mdl-21364273

ABSTRACT

OBJECTIVES: Assessment of additive impact of alfacalcidol 1 µg daily (Alfa) on bone mineral density (BMD) and on bone strength in postmenopausal women treated with alendronate 70 mg weekly + 500 mg calcium daily. SUBJECTS AND METHODS: In a randomized, double-blind, placebo controlled study, 279 postmenopausal women with osteoporosis or osteopenia participated (intention to treat analysis [ITT]; aged 73.6∓4.7 years) and were treated with 70 mg alendronate (ALN) weekly and 500 mg calcium daily for 36 months. In addition, these patients received either 1 µg alfacalcidol (Alfa) or placebo (PLC) daily. BMD was measured with Dual-Energy-X-ray-Absorptiometry (DXA) at the lumbar spine and proximal femur and at forearm and tibia with peripheral quantitative computed tomography (pQCT) at regular intervals for 36 months. RESULTS: DXA-BMD of lumbar spine (L1-4) increased after 36 months, by 6.65% (p<0.0001) in the Alfa/ALN group versus 4.17% (p<0.0001) in the PLC/ALN group. Group difference was significant after 3 years (p=0.026). At the end of the study, significant differences were found in favor of the Alfa/ALN group in trabecular density (tibia) (p=0.002), cortical density (midshaft tibia) (p=0.043), and bone strength (p=0.001). The remaining parameters showed no differences between the treatment arms, apart cortical bone density at midshaft radius. CONCLUSIONS: Alfacalcidol significantly increases the efficacy of alendronate treatment in osteopenic/osteoporotic postmenopausal women on spinal DXA-BMD, cortical and trabecular BMD of the tibia and also bending stiffness of the tibia.


Subject(s)
Alendronate/administration & dosage , Bone Density Conservation Agents/administration & dosage , Bone Density/drug effects , Bone Resorption/drug therapy , Bone and Bones/drug effects , Hydroxycholecalciferols/administration & dosage , Osteoporosis, Postmenopausal/drug therapy , Aged , Alendronate/adverse effects , Bone Density/physiology , Bone Density Conservation Agents/adverse effects , Bone Resorption/physiopathology , Double-Blind Method , Drug Therapy, Combination , Female , Humans , Hydroxycholecalciferols/adverse effects , Osteoporosis, Postmenopausal/diagnostic imaging , Osteoporosis, Postmenopausal/physiopathology , Radiography
6.
Biomacromolecules ; 12(5): 1387-408, 2011 May 09.
Article in English | MEDLINE | ID: mdl-21388145

ABSTRACT

Hydrogels are physically or chemically cross-linked polymer networks that are able to absorb large amounts of water. They can be classified into different categories depending on various parameters including the preparation method, the charge, and the mechanical and structural characteristics. The present review aims to give an overview of hydrogels based on natural polymers and their various applications in the field of tissue engineering. In a first part, relevant parameters describing different hydrogel properties and the strategies applied to finetune these characteristics will be described. In a second part, an important class of biopolymers that possess thermosensitive properties (UCST or LCST behavior) will be discussed. Another part of the review will be devoted to the application of cryogels. Finally, the most relevant biopolymer-based hydrogel systems, the different methods of preparation, as well as an in depth overview of the applications in the field of tissue engineering will be given.


Subject(s)
Biopolymers , Hydrogels , Tissue Engineering
7.
Biomacromolecules ; 11(10): 2731-9, 2010 Oct 11.
Article in English | MEDLINE | ID: mdl-20831199

ABSTRACT

In the present work, two strategies were elaborated to surface-functionalize implantable polyimide sheets. In the first methodology, cross-linkable vinyl groups were introduced on the polyimide surface using aminopropylmethacrylamide. In the second approach, a reactive succinimidyl ester was introduced on the surface of PI. Using the former approach, the aim is to apply a vinyl functionalized biopolymer coating. In the latter approach, any amine containing biopolymer can be immobilized. The foils developed were characterized in depth using a variety of characterization techniques including atomic force microscopy, static contact angle measurements, and X-ray photoelectron spectroscopy. The results indicated that both modification strategies were successful. The subcutaneous implantation in mice indicated that both modification strategies resulted in biocompatible materials, inducing only limited cellular infiltration to the surrounding tissue.


Subject(s)
Biocompatible Materials/chemistry , Regenerative Medicine , Resins, Synthetic/chemistry , Acrylamides/chemistry , Animals , Biocompatible Materials/adverse effects , Cross-Linking Reagents/chemistry , Cytokines/blood , Female , Implants, Experimental/adverse effects , Male , Mechanical Phenomena , Mice , Mice, Inbred BALB C , Mice, Inbred C57BL , Microscopy, Atomic Force , Molecular Structure , Photoelectron Spectroscopy , Resins, Synthetic/adverse effects , Surface Properties
8.
Vet Comp Orthop Traumatol ; 23(3): 153-62, 2010.
Article in English | MEDLINE | ID: mdl-20422117

ABSTRACT

Methods currently used to restore bone defects in human and veterinary orthopaedics are often not satisfactory. This is especially the case in the healing of large, irregular defects which result in the formation of tissues with inferior qualities compared to the original structures. For these reasons, several new approaches are currently being explored to improve bone healing capacities in different situations. This review will examine the different techniques used to enhance bone regeneration, highlighting both experimental and clinically applicable methods with regard to veterinary orthopaedics.


Subject(s)
Fractures, Bone/metabolism , Fractures, Bone/therapy , Joint Diseases/veterinary , Orthopedics/veterinary , Regeneration/physiology , Animals , Bone Substitutes , Joint Diseases/therapy , Orthopedics/trends
9.
Osteoporos Int ; 21(7): 1237-45, 2010 Jul.
Article in English | MEDLINE | ID: mdl-19771489

ABSTRACT

UNLABELLED: We assessed in a cross-sectional study in elderly men and women with osteoporosis, the association between the creatinine clearance (CrCl) and the performance in different balance and muscle power and function tests and found that a decreasing creatinine clearance was significantly associated with lower balance and muscle power. INTRODUCTION: To determine if a creatinine clearance of <65 ml/min is significantly associated with decreasing muscle power and balance and an increased risk for falls and fractures. METHODS: We assessed in a cross-sectional-study in 1781 German osteoporotic patients, the association between the CrCl, the physical performance, and the number of falls and fractures. RESULTS: Controlling for age, gender, BMI, and osteoporosis treatment (fracture analysis only), a decreasing CrCl was associated with lower physical performance in the timed-up-and-go test (corr -0.2337, P < 0.0001), chair-rising test (corr -0.1706, P < 0.001), and tandem-stand test (corr 0.2193, P < 0.0001), and a CrCl of <65 ml/min was associated with a significantly higher risk for falls (47.7% vs. 36.2%, P = 0.0008) and fall-related fractures (33.1% vs. 22.9%, P = 0.0003) compared with a CrCl of >or=65 ml/min. CONCLUSIONS: In this study, we found a significant gender-independent correlation between decreasing CrCl and lower performance in balance and muscle power tests. Reduced muscle power and balance may therefore be involved in the low creatinine clearance associated increased risk for falls and fall-related fractures. Furthermore, we found that a CrCl <65 ml/min., independent from the performance in muscle power, muscle function, and balance tests, is a significant risk factor for falls and fractures.


Subject(s)
Accidental Falls , Creatinine/blood , Muscle Strength/physiology , Osteoporotic Fractures/etiology , Postural Balance/physiology , Aged , Aged, 80 and over , Cross-Sectional Studies , Female , Humans , Male , Middle Aged , Osteoporosis/blood , Osteoporotic Fractures/blood , Risk Factors
10.
Article in English | MEDLINE | ID: mdl-19963629

ABSTRACT

In the frame of the Flemish Community funded project Bioflex we developed and fabricated an implant for short term (< 7 days) bladder pressure monitoring, and diagnosis of incontinence. This implant is soft and flexible to prevent damaging the bladder's inner wall. It contains a standard flexible electronic circuit connected to a battery, which are embedded in surface treated silicone to enhance the biocompatibility and prevent salt deposition. This article describes the fabrication of the pill and the results of preliminary cytotoxicity tests. The electronic design and its tests, implantation and the result of the in-vivo experimentation will be presented in other articles.


Subject(s)
Equipment Design/instrumentation , Pressure , Prostheses and Implants , Prosthesis Design/instrumentation , Urinary Bladder/physiology , Equipment Design/methods , Humans , Prosthesis Design/methods , Urodynamics
11.
Article in English | MEDLINE | ID: mdl-19680963

ABSTRACT

A molecularly imprinted polymer (MIP) for the recognition of fumonisin B analogues (FB) using 2-(diethylamino) ethyl methacrylate (DEAEM) as functional monomer and trimethylolpropane trimethacrylate (TRIM) as cross-linker was prepared by bulk polymerization in acetonitrile. Fumonisin B(1) (FB(1)) was used as a template molecule. A molecularly imprinted solid-phase extraction (MISPE) procedure was developed for further application in the analysis of FB. The performance of the MIP throughout the clean-up of spiked bell pepper, rice and corn flake sample extracts was compared with the results obtained when using non-imprinted polymer, C(18), strong anion exchange and immunoaffinity sorbents. Extracts were analysed for FB with liquid chromatography-tandem mass spectrometry (LC-MS/MS) after clean-up. Depending on the food matrix and the concentration range of the fumonisins, recoveries after MISPE varied from 62 to 86%, from 62 to 83%, and from 67 to 81% for fumonisin B(1) (FB(1)), fumonisin B(2) (FB(2)) and fumonisin B(3) (FB(3)), respectively. The selectivity of the synthesized MIP for mycotoxins belonging to the group of FB was confirmed by evaluating cross-reactivity from analogue structures and other mycotoxins. Analysis of 39 naturally contaminated samples (corn flakes) by liquid chromatography tandem mass spectrometry indicated that the synthesized MIP could be an excellent alternative for clean-up and pre-concentration of FB in food samples. Pearson correlations between immunoaffinity clean-up and MISPE were calculated and amounted to 0.923 for FB(1), 0.808 for FB(2), and 0.759 for FB(3). It was shown that the developed MIP could be reused more than 50 times. The synthesis of an FB(1) imprinted polymer and its application in food analysis is reported for the first time.


Subject(s)
Capsicum/chemistry , Food Contamination/analysis , Fumonisins/analysis , Oryza/chemistry , Zea mays/chemistry , Chromatography, Liquid/methods , Food Analysis/methods , Fumonisins/chemistry , Molecular Imprinting/methods , Solid Phase Extraction/methods
12.
J Biomater Sci Polym Ed ; 20(10): 1417-38, 2009.
Article in English | MEDLINE | ID: mdl-19622280

ABSTRACT

In the present work, we have performed an in-depth physico-chemical and bio-physical evaluation of a series of previously described porous gelatin scaffolds (S. VanVlierberghe, V. Cnudde, P. Dubruel, B. Masschaele, A. Cosijns, I. DePaepe, P.J.S. Jacobs, L. VanHoorebeke, J.P. Remon and E. Schacht, Biomacromolecules 8, 331 (2007)). All scaffolds were prepared by a cryogenic treatment and subsequent freeze-drying. Three types of scaffolds were prepared by using different gelatin concentrations and cooling protocols. Type-I hydrogels were composed of cone-like pores with decreasing diameter from top (330 microm) to bottom (20-30 microm). Type-II and type-III scaffolds contained spherical pores with an average diameter of 135 (type II) and 65 microm (type III), respectively. The physico-chemical and bio-physical properties studied include the water uptake capacity and kinetics, the mechanical properties and the enzyme-mediated degradation. We can conclude that the pore geometry affects the water uptake capacity, the mechanical properties and the degradation profile of the hydrogels. Type-I hydrogels possess the highest water uptake, the lowest compression modulus and the fastest enzyme mediated degradation, indicating a clear effect of the pore morphology (elongated channels for type I versus spherical pores for types II and III) on the physico-chemical and bio-physical properties of the materials. In contrast to the effect of the pore geometry (channel-like versus spherical), the pore size does not significantly affect the water uptake, the mechanical properties and the enzyme mediated degradation in the investigated pore size range (65-135 microm). To the best of our knowledge, this is the first report in which the effects of a cryogenic treatment on the hydrogel network properties are investigated in such detail.


Subject(s)
Gelatin/chemistry , Hydrogels/chemistry , Tissue Scaffolds/chemistry , Animals , Cattle , Cross-Linking Reagents , Elastic Modulus , Freeze Drying , Porosity , Volatilization , Water/chemistry
13.
Eur J Pharm Biopharm ; 72(2): 463-70, 2009 Jun.
Article in English | MEDLINE | ID: mdl-19462482

ABSTRACT

Over the last few decades, polysaccharides have gained increasing attention in the biomedical and drug delivery fields. Among them, glucomannan (GM), has become a particularly attractive polymer. In this paper, we review the physicochemical and biological properties which are decisive for the exploitation of GM as a biomaterial. These properties include the structural organization, molecular weight, solubility, viscosity, gelling properties and degradation behavior. Moreover, herein we analyze the possibilities of combining GM with other hydrophilic polymers, as well as the preparation of semisynthetic derivatives of GM, which may be of interest in the pharmaceutical context. Finally, we discuss the specific applications of GM in the drug delivery field.


Subject(s)
Cellulose/chemistry , Hot Temperature , Polyethylene Glycols/chemistry , Area Under Curve , In Vitro Techniques , Spectrum Analysis, Raman , X-Ray Diffraction
14.
Rheumatol Int ; 29(10): 1177-85, 2009 Aug.
Article in English | MEDLINE | ID: mdl-19159932

ABSTRACT

There are no general accepted strategies for combined drug treatments in osteoporosis, while in other important chronic diseases combinations of different medications are used as a rule to improve therapeutic results and reduce the risk of adverse events. It is suggested that the success of combined treatments is related to the different modes of action of the respective single therapies. On the other hand it was shown that a strong antiresorptive bisphosphonate is able to blunt at least in part the effects of anabolic parathyroid hormone peptides Calcitriol, the active vitamin D-hormone and its prodrug alfacalcidol lead to pleiotropic effects on bone remodelling (antiresorptive, anabolic and enhancing mineralization) and in addition to effects on other important target tissues (e.g. gut, parathyroid glands, muscle). With active D-analogs significant improvements in the therapeutic outcome of osteoporosis can be achieved by the resulting improvements of bone quality, calcium absorption and risk reduction of falling. The same beneficial effects cannot be achieved with plain vitamin D due to feedback controlled, limited renal activation or insufficient conversion in the elderly with impairment of renal function. Accordingly alfacalcidol, approved as a treatment for different forms of osteoporosis, is besides adoption as a mono-therapy an interesting candidate for combined therapies. There are interesting preclinical trials and clinical pilote studies in the literature proving that a parallel therapy with selectively anti-osteoclastic bisphophonates and pleiotropically acting D-analogs is able to optimize therapeutic results in osteoporosis. In the AAC-Trial (Alfacalcidol-Alendronate-Combined) we studied 90 patients with established osteoporosis (57 women, 33 men) over two years after alternate allocation to three treatment arms (alfacalcidol plus calcium, alendronate plus plain vitamin D and Ca, and alendronate plus alfacalcidol and Ca). During the 2-year-study we observed the significantly highest lumbar spine and hip BMD increases in the combined treatment group (p < 0.001). The number of patients with new vertebral and non-vertebral fractures after 2 years was 9 with alfacalcidol alone, 10 with alfacalcidol and plain vitamin D and 2 in the group receiving alendronate plus alfacalidol (p < 0.02). Furthermore there was a lower rate of falls and an earlier reduction in back pain in the patients treated with the active combination. This trial confirms the demonstrated highly significant advantages of this combined treatment regimen used in the pilote studies. Especially in patients with severe osteoporosis this interesting combination of two substances with complete different mechanisms of action should be taken into consideration.


Subject(s)
Accidental Falls/prevention & control , Bone Density Conservation Agents/therapeutic use , Fractures, Bone/prevention & control , Hydroxycholecalciferols/therapeutic use , Aged , Alendronate/adverse effects , Alendronate/therapeutic use , Bone Density/drug effects , Bone Density Conservation Agents/adverse effects , Calcitriol/adverse effects , Calcitriol/therapeutic use , Calcium/adverse effects , Calcium/therapeutic use , Clinical Trials as Topic , Diphosphonates/adverse effects , Diphosphonates/therapeutic use , Double-Blind Method , Drug Therapy, Combination , Female , Follow-Up Studies , Glucocorticoids/pharmacology , Humans , Hydroxycholecalciferols/adverse effects , Lumbar Vertebrae/drug effects , Male , Meta-Analysis as Topic , Osteoporosis/chemically induced , Osteoporosis/classification , Osteoporosis/drug therapy , Risk Factors , Time Factors , Treatment Outcome , Vitamin D/adverse effects , Vitamin D/therapeutic use
15.
J Mater Sci Mater Med ; 19(4): 1459-66, 2008 Apr.
Article in English | MEDLINE | ID: mdl-18299964

ABSTRACT

The design, development and evaluation of biomaterials that can sustain life or restore a certain body function, is a very important and rapidly expanding field in materials science. A key issue in the development of biomaterials is the design of a material that mimics the natural environment of cells. In the present work, we have therefore developed hydrogel materials that contain both a protein (gelatin) and a glycosaminoglycan (chondroitin sulphate) component. To enable a permanent crosslinking, gelatin and chondroitin sulphate were first chemically modified using methacrylic anhydride. Hydrogels containing modified gelatin (gel-MOD) and/or chondroitin sulphate (CS-MOD) were cryogenically treated as optimised earlier for gel-MOD based hydrogels (Van Vlierberghe et al., Biomacromolecules 8:331-337, 2007). The cryogenic treatment leads to tubular pores for gel-MOD based systems. For CS-MOD based hydrogels and hydrogels containing both gel-MOD and CS-MOD, a curtain-like architecture (i.e. parallel plates) was observed, depending on the applied CS-MOD concentration. In our opinion, this is the first paper in which such well-defined scaffold architectures have been obtained without using rapid prototyping techniques.


Subject(s)
Glycosaminoglycans/chemistry , Hydrogels/chemistry , Anhydrides/chemistry , Biocompatible Materials/chemistry , Cell Line, Tumor , Chondroitin Sulfates/chemistry , Freezing , Gelatin/chemistry , HeLa Cells , Humans , Materials Testing , Microscopy, Atomic Force , Microscopy, Confocal , Protein Engineering/methods , Tomography, X-Ray Computed/methods
16.
Article in English | MEDLINE | ID: mdl-18003536

ABSTRACT

For user comfort reasons, electronic circuits for implantation in the human body or for use as smart clothes should ideally be soft, stretchable and elastic. In this contribution the results of an MID (Molded Interconnect Device) technology will be presented, showing the feasibility of functional stretchable electronic circuits. In the developed technology rigid or flexible standard components are interconnected by meander shaped metallic wires and embedded by molding in a stretchable substrate polymer. Several technologies have been developed to this purpose, which combine low cost and good reliability under mechanical strain. In this way reliable stretchability of the circuits above 100% has been demonstrated. Enhanced reliability has been reached using an additional conductive polymer layer.


Subject(s)
Coated Materials, Biocompatible , Electronics , Silicone Elastomers , Vinyl Compounds , Copper , Elasticity , Finite Element Analysis , Gold , Hydrophobic and Hydrophilic Interactions , Nickel , Prostheses and Implants , Stress, Mechanical , Telemetry/instrumentation , Textiles
17.
Rheumatol Int ; 28(2): 103-11, 2007 Dec.
Article in English | MEDLINE | ID: mdl-17668216

ABSTRACT

While in other chronic diseases combined treatment regimens are the rule there is a lack of reported experience or study data on combining different specific drugs to treat osteoporosis. Significant differences in the mode of action (MOA) of the substances to be combined may be important for achieving optimal therapeutic results. Recognising that today bisphosphonates are the leading therapy for osteoporosis we suggest that the active D-hormone analog alfacalcidol with its completely different mechanisms of action could be an interesting combination to improve the therapeutic outcome of the pure antiresoptive action of bisphosphonates. Alfacalcidol is activated by the enzyme 25-hydroxylase in the liver for systemic and in osteoblasts for local D-hormone actions. It possesses a unique pattern of pleiotropic effects on, e.g. gut, bone, pararthyroids, muscle and brain. Alfacalcidol is superior to plain vitamin D (cholecalciferol) because the final kidney activation of the latter is regulated by a negative feedback mechanism. In vitamin D replete patients or patients with impaired kidney function no increased D-hormone action at the target tissues can be achieved. Animal studies and several trials in humans with alendronate plus calcitriol or alfacalcidol proved that the combination induced significantly higher increases of bone mineral density (BMD) than the respective mono-therapies. The results of the 2-year AAC-trial from our group indicate that the combination alendronate and alfacalcidol is also superior in terms of falls, fractures and back pain. From the review of the literature and the own new results we conclude that this combined therapeutic regimen is a very promising option for treating established osteoporosis and propose a differentiated use of alfacalcidol alone or the combination with alendronate in different stages and clinical situations of osteoporosis.


Subject(s)
Bone Density Conservation Agents/therapeutic use , Diphosphonates/therapeutic use , Hydroxycholecalciferols/therapeutic use , Osteoporosis/drug therapy , Vitamin D/analogs & derivatives , Vitamin D/therapeutic use , Alendronate/adverse effects , Alendronate/therapeutic use , Animals , Bone Density/drug effects , Bone Density Conservation Agents/adverse effects , Calcitriol/adverse effects , Calcitriol/therapeutic use , Diphosphonates/adverse effects , Drug Therapy, Combination , Humans , Treatment Outcome
18.
Article in English | MEDLINE | ID: mdl-17627088

ABSTRACT

During the last two decades, the development of new, highly effective therapeutics (e.g. bisphosphonates, SERMs, strontium ranelate and PTH) has significantly extended the spectrum of osteoporosis therapy. However, the interest of combining bone-active agents and/or Vitamin D and calcium is still being debated, and is restricted to a very marginal set of compounds (Alendronate and native Vitamin D). On the other hand, Vitamin D-hormone analogs, calcitriol, and alfacalcidol, have repeatedly demonstrated their effectiveness in being valuable alternatives compared to native Vitamin D in this setting. A growing amount of data documents the pre-clinical and clinical efficacies of combinations of bisphosphonates with calcitriol, or with alfacalcidol in primary and secondary osteoporosis. This exhaustive review of the available animal and clinical data aimed at comparing the theoretical with demonstrated absolute and relative benefits of those therapeutic approaches. Most of the pre-clinical and clinical data in PMOP suggest significant, clinical improvements in response to combination therapies versus monotherapies in postmenopausal osteoporosis. As a investigated by most of the currently available trials, a daily dose of alendronate 10 mg or a weekly dose of Alendronate 70 m plus alfacalcidol 0.5-1.0 microg daily plus alfacalcidol 0.5 microg seems to surpass other combinations when BMD and bone metabolism markers are considered. A synergy with bisphosphonates in reducing the fracture episodes may lie in the pleiotropic effects of D-hormone analogs on musculoskeletal, immunological and neurological systems. Negative interactions between both drugs have not yet been reported, while a reduction of hypercalcuria episodes has been noted in combination therapies, as compared to monotherapies involving high doses of Vitamin D, calcitriol, or alfacalcidol. Based on the possible reduction of periodic safety checks of calcemia, an improved compliance could then be expected, which would, in turn, generate a better end result. However, to document this, long-term, high quality comparative studies with factorial designs are needed to determine which role this alternative should play in the management of postmenopausal, male, and glucocorticoid-induced osteoporosis.


Subject(s)
Bone Density Conservation Agents/pharmacology , Bone Density/drug effects , Diphosphonates/pharmacology , Osteoporosis/drug therapy , Vitamin D/analogs & derivatives , Alendronate/administration & dosage , Animals , Bone Density/physiology , Bone Density Conservation Agents/therapeutic use , Diphosphonates/therapeutic use , Drug Combinations , Drug Synergism , Humans , Hydroxycholecalciferols/administration & dosage , Osteoporosis/metabolism , Osteoporosis/physiopathology
19.
Biomacromolecules ; 8(3): 825-32, 2007 Mar.
Article in English | MEDLINE | ID: mdl-17266367

ABSTRACT

Mouse embryonic stem cells were cultured on commercially available biodegradable macroporous microcarriers. A culture period of 1-2 weeks was needed to colonize the microcarriers. Embryonic stem cells retained their pluripotency for up to 14 days when cultured in medium supplemented with leukemia inhibitory factor. Replacing this medium by differentiation medium for 2 weeks initiated osteogenic differentiation. Encapsulation of the cell-loaded microcarriers in photopolymerizable polymers (methacrylate-endcapped poly-D,L-lactide-co-caprolactone), triacetin/hydroxyethylmethacrylate (HEMA) as solvent and with/without gelatin as porogen, resulted in a homogeneous distribution of the microcarriers in the polymer. As observed by transmission electron microscopy, viability of the cells was optimal when gelatin was omitted and when using triacetin instead of HEMA.


Subject(s)
Bone and Bones/metabolism , Embryonic Stem Cells/cytology , Gelatin/chemistry , Tissue Engineering/methods , Animals , Biodegradation, Environmental , Cell Differentiation , Cell Survival , Cells, Cultured , Methacrylates/chemistry , Mice , NIH 3T3 Cells , Osteocalcin/metabolism , Polyesters/chemistry , Triacetin/chemistry
20.
Rheumatol Int ; 27(5): 425-34, 2007 Mar.
Article in English | MEDLINE | ID: mdl-17216477

ABSTRACT

A combined therapy with the strongly antiresorptive Alendronate and the pleiotropically acting D-hormone analogue Alfacalcidol may have additive effects on bone quality, falls and fracture risk in established osteoporosis. The aim of this study (Alfacalcidol Alendronate Combined-AAC) was to compare the efficacy and safety of a combined parallel therapy with Alendronate and Alfacalcidol to the treatment with either Alendronate in combination with plain vitamin D or Alfacalcidol alone in patients with established postmenopausal or male osteoporosis. Ninety patients were included as matched triplets to receive randomly either 1 microg Alfacalcidol daily + 500 mg calcium (group A, n = 30) or 70 mg Alendronate weekly + 1,000 mg calcium + 1,000 IU vitamin D daily (group B, n = 30) or 1 microg Alfacalcidol daily + 70 mg Alendronate weekly + 500 mg calcium daily (group C, n = 30). Patients were recruited in one centre and were followed up for 24 months. Analysis was intention-to-treat and the primary outcome was lumbar spine and total hip bone mineral density (measured observer blind). BMD was measured at the lumbar spine and at the proximal femur with dual energy X-ray absorptiometry (LUNAR Prodigy, GE, USA) at the beginning and after 12 and 24 months. During the 2-year-study we observed descriptively significant increases at the lumbar spine of 3.0% in group A compared to baseline, of 5.4% in group B and of 9.6% in group C, respectively. The superiority of the Alendronate + Alfacalcidol treatment group over Alfacalcidol alone and over Alendronate + vitamin D was of more than large rele-vance (both tests: MW > 0.71; CI-LB > 0.64; P < 0.001). We also observed median increases of the BMD at the total hip of 1.5% in group A, of 2.4% in group B and of 3.8% in group C, respectively. The superiority of group C over group A and over group B again was relevant and statistically significant in a descriptive sense. After 2 years there was a tendency towards higher rates of vertebral and non-vertebral fractures in group A and B as compared to C. Taking both fracture types together we observed 9, 10 and 2 "osteoporotic fractures" in groups A, B and C, respectively. The comparison of group C with pooled groups A and B and with each single group gave a relevantly lower fracture rate for the combination of Alendronate and Alfacalcidol. Furthermore a lower rate of falls was observed for the combination Alendronate plus Alfacalcidol versus Alendronate + vitamin D, but not versus Alfacalcidol alone. We found 80% of the patients in the Alendronate + Alfacalcidol group free from back pain at month 24, compared to 30% in the Alendronate + vitamin D and 43% in the Alfacalcidol monotherapy group. The superiority is relevant (both tests: MW > 0.64; CI-LB > 0.56; P < 0.003). Pain decrease also occurred more rapidly in the Alendronate + Alfacalcidol group than in the other groups. In general side effects in all groups were mild, and only four cases of moderate hypercalcuria in group A and one in group C were reported, but no case of hypercalcemia was documented. In conclusion, the combination therapy with Alendronate and Alfacalcidol exhibited superiority in terms of BMD, overall fractures, rate of falls and back pain over either Alendronate in combination with plain vitamin D or Alfacalcidol alone. The overall safety profiles of the three treatment regimens were found to be not different in this study.


Subject(s)
Alendronate/therapeutic use , Bone Density Conservation Agents/therapeutic use , Bone Density/drug effects , Hydroxycholecalciferols/therapeutic use , Osteoporosis, Postmenopausal/drug therapy , Aged , Alendronate/adverse effects , Bone Density Conservation Agents/adverse effects , Drug Therapy, Combination , Female , Humans , Hydroxycholecalciferols/adverse effects , Male , Middle Aged , Spinal Fractures/drug therapy , Spinal Fractures/prevention & control , Treatment Outcome , Vitamin D/adverse effects , Vitamin D/therapeutic use
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