Wettability of mg-ha/Chitosan-based membrane surfaces: blood vs. autologous platelet liquid (APL)

OBJECTIVE

The physical and physical chemistry is able to influence the interaction of the scaffolds and bone substitutes with the body fluid and blood. The aim of the present investigation was to evaluate the wettability properties of an Mg-HA Chitosan-based Gel with blood vs. autologous platelet gel.

MATERIALS AND METHODS

A total of 6 study groups were evaluated according to the Mg-HA Chitosan-based Gel thickness (1, 2 and 3 mm) and the fluids (blood vs. autologous platelet gel). The biomaterial wettability was conducted through the sessile drop technique.

RESULTS

The study findings showed a significant difference in contact angle between the APL and blood groups (p<0.05). The MG-Ha Chitosan-based membrane thicknesses seem to produce no significant effects on contact angles measurement for all groups (p>0.05).

CONCLUSIONS

In the present investigation, a similar MG/Ha gel membranes wettability was reported between APL and blood groups. In addition, a high hydrophilicity of MG/Ha gel membranes was reported with a potential advantage in terms of a more effective osteogenic capability in the clinical practice.

3D Patterning of cells in Magnetic Scaffolds for Tissue Engineering

A three dimensional magnetic patterning of two cell types was realised in vitro inside an additive manufactured magnetic scaffold, as a conceptual precursor for the vascularised tissue. The realisation of separate arrangements of vascular and osteoprogenitor cells, labelled with biocompatible magnetic nanoparticles, was established on the opposite sides of the scaffold fibres under the effect of non-homogeneous magnetic gradients and loading magnetic configuration. The magnetisation of the scaffold amplified the guiding effects by an additional trapping of cells due to short range magnetic forces. The mathematical modelling confirmed the strong enhancement of the magnetic gradients and their particular geometrical distribution near the fibres, defining the preferential cell positioning on the micro-scale. The manipulation of cells inside suitably designed magnetic scaffolds represents a unique solution for the assembling of cellular constructs organised in biologically adequate arrangements.

Ceramics with the signature of wood: a mechanical insight

In an attempt to mimic the outstanding mechanical properties of wood and bone, a 3D heterogeneous chemistry approach has been used in a biomorphic transformation process (in which sintering is avoided) to fabricate ceramics from rattan wood, preserving its hierarchical fibrous microstructure. The resulting material (called biomorphic apatite ​[BA] henceforth) possesses a highly bioactive composition and is characterised by a multiscale hierarchical pore structure, based on nanotwinned hydroxyapatite lamellae, which is shown to display a lacunar fractal nature. The mechanical properties of BA are found to be exceptional (when compared with usual porous hydroxyapatite and other ceramics obtained from wood through sintering) and unique ​as they occupy a zone in the Ashby map previously free from ceramics, but not far from wood and bone. Mechanical tests show the following: (i) the strength in tension may exceed that in compression, (ii) failure in compression involves complex exfoliation patterns, thus resulting in high toughness, (iii) unlike in sintered porous hydroxyapatite, fracture does not occur 'instantaneously,' ​but its growth may be observed, and it exhibits tortuous patterns that follow the original fibrillar structure of wood, thus yielding outstanding toughness, (iv) the anisotropy of the elastic stiffness and strength show unprecedented values when situations of stresses parallel and orthogonal to the main channels are compared. Despite being a ceramic material, BA displays a mechanical behavior similar on the one hand to the ligneous material from which it was produced (therefore behaving as a 'ceramic with the signature of wood') and on the other hand to the cortical/spongy osseous complex constituting the structure of compact bone.

Biomimetic hydroxyapatite/collagen composite drives bone niche recapitulation in a rabbit orthotopic model

Synthetic osteoinductive materials that mimic the human osteogenic niche have emerged as ideal candidates to address this area of unmet clinical need. In this study, we evaluated the osteoinductive potential in a rabbit orthotopic model of a magnesium-doped hydroxyapatite/type I collagen ​(MHA/Coll) composite. The composite was fabricated to exhibit a highly fibrous structure of carbonated MHA with 70% (±2.1) porosity and a Ca/P ratio of 1.5 (±0.03) as well as a diverse range of elasticity separated to two distinct stiffness peaks of low (2.35 ​± ​1.16 ​MPa) and higher (9.52 ​± ​2.10 ​MPa) Young's Modulus. Data suggested that these specific compositional and nanomechanical material properties induced the deposition of de novo mineral phase, while modulating the expression of early and late osteogenic marker genes, in a 3D in vitro model using human bone marrow-derived mesenchymal stem cells (hBM-MSCs). When tested in the rabbit orthotopic model, MHA/Col1 scaffold induction of new trabecular bone mass was observed by DynaCT scan, only 2 weeks after implantation. Bone histomorphometry at 6 weeks revealed a significant amount of de novo bone matrix formation. qPCR demonstrated MHA/Coll scaffold full cellularization in vivo and the expression of both osteogenesis-associated genes (Spp1, Sparc, Col1a1, Runx2, Dlx5) as well as hematopoietic (Vcam1, Cd38, Sele, Kdr) and bone marrow stromal cell marker genes (Vim, Itgb1, Alcam). Altogether, these data provide ​evidence of the solid osteoinductive potential of MHA/Coll and its suitability for multiple approaches of bone regeneration.

Surface morphology, tribological properties and in vitro biocompatibility of nanostructured zirconia thin films

Deposition of nanostructured and low-wear zirconia (ZrO2) thin films on the metallic component of a total joint implant is envisaged to reduce wear of the soft ultra-high molecular weight polyethylene (UHMWPE) counterpart. In this work, morphological surface features, wear resistance and in vitro-biocompatibility of zirconia thin films deposited by the novel Pulsed Plasma Deposition (PPD) method have been investigated. Film thickness, roughness and wettability were found to be strongly dependent on deposition gas pressure. Interestingly, wear rate of UHMWPE disks coupled to zirconia-coated titanium spheres was only poorly correlated to the contact angle values, while film roughness and thickness seemed not to affect it. Furthermore, wear of UHMWPE, when coupled with zirconia coated-titanium spheres, significantly decreased with respect to uncoated spheres under dry or NaCl-lubricated conditions; besides, when using bovine serum, similar results were obtained for coated and uncoated spheres. Finally, suitable mesenchymal stem and osteoblast cells adhesion, proliferation and viability were observed, suggesting good biocompatibility of the nanostructured zirconia films. Taken together, the results shown in this work indicate that zirconia thin films deposited by the PPD method deserve further investigations as low-wear materials for biomedical applications such as total joint replacement.

Needle-like ion-doped hydroxyapatite crystals influence osteogenic properties of PCL composite scaffolds

Surface topography and chemistry both play a crucial role on influencing cell response in 3D porous scaffolds in terms of osteogenesis. Inorganic materials with peculiar morphology and chemical functionalities may be proficiently used to improve scaffold properties-in the bulk and along pore surface-promoting in vitro and in vivo osseous tissue in-growth. The present study is aimed at investigating how bone regenerative properties of composite scaffolds made of poly(Ɛ-caprolactone) (PCL) can be augmented by the peculiar properties of Mg(2+) ion doped hydroxyapatite (dHA) crystals, mainly emphasizing the role of crystal shape on cell activities mediated by microstructural properties. At the first stage, the study of mechanical response by crossing experimental compression tests and theoretical simulation via empirical models, allow recognizing a significant contribution of dHA shape factor on scaffold elastic moduli variation as a function of the relative volume fraction. Secondly, the peculiar needle-like shape of dHA crystals also influences microscopic (i.e. crystallinity, adhesion forces) and macroscopic (i.e. roughness) properties with relevant effects on biological response of the composite scaffold: differential scanning calorimetry (DSC) analyses clearly indicate a reduction of crystallization heat-from 66.75 to 43.05 J g(-1)-while atomic force microscopy (AFM) ones show a significant increase of roughness-from (78.15  ±  32.71) to (136.13  ±  63.21) nm-and of pull-off forces-from 33.7% to 48.7%. Accordingly, experimental studies with MG-63 osteoblast-like cells show a more efficient in vitro secretion of alkaline phosphatase (ALP) and collagen I and a more copious in vivo formation of new bone trabeculae, thus suggesting a relevant role of dHA to support the main mechanisms involved in bone regeneration.

Modifying bone scaffold architecture in vivo with permanent magnets to facilitate fixation of magnetic scaffolds

The fundamental elements of tissue regeneration are cells, biochemical signals and the three-dimensional microenvironment. In the described approach, biomineralized-collagen biomaterial functions as a scaffold and provides biochemical stimuli for tissue regeneration. In addition superparamagnetic nanoparticles were used to magnetize the biomaterials with direct nucleation on collagen fibres or impregnation techniques. Minimally invasive surgery was performed on 12 rabbits to implant cylindrical NdFeB magnets in close proximity to magnetic scaffolds within the lateral condyles of the distal femoral epiphyses. Under this static magnetic field we demonstrated, for the first time in vivo, that the ability to modify the scaffold architecture could influence tissue regeneration obtaining a well-ordered tissue. Moreover, the association between NdFeB magnet and magnetic scaffolds represents a potential technique to ensure scaffold fixation avoiding micromotion at the tissue/biomaterial interface.

Magnetic poly(ε-caprolactone)/iron-doped hydroxyapatite nanocomposite substrates for advanced bone tissue engineering

In biomedicine, magnetic nanoparticles provide some attractive possibilities because they possess peculiar physical properties that permit their use in a wide range of applications. The concept of magnetic guidance basically spans from drug delivery and hyperthermia treatment of tumours, to tissue engineering, such as magneto-mechanical stimulation/activation of cell constructs and mechanosensitive ion channels, magnetic cell-seeding procedures, and controlled cell proliferation and differentiation. Accordingly, the aim of this study was to develop fully biodegradable and magnetic nanocomposite substrates for bone tissue engineering by embedding iron-doped hydroxyapatite (FeHA) nanoparticles in a poly(ε-caprolactone) (PCL) matrix. X-ray diffraction analyses enabled the demonstration that the phase composition and crystallinity of the magnetic FeHA were not affected by the process used to develop the nanocomposite substrates. The mechanical characterization performed through small punch tests has evidenced that inclusion of 10 per cent by weight of FeHA would represent an effective reinforcement. The inclusion of nanoparticles also improves the hydrophilicity of the substrates as evidenced by the lower values of water contact angle in comparison with those of neat PCL. The results from magnetic measurements confirmed the superparamagnetic character of the nanocomposite substrates, indicated by a very low coercive field, a saturation magnetization strictly proportional to the FeHA content and a strong history dependence in temperature sweeps. Regarding the biological performances, confocal laser scanning microscopy and AlamarBlue assay have provided qualitative and quantitative information on human mesenchymal stem cell adhesion and viability/proliferation, respectively, whereas the obtained ALP/DNA values have shown the ability of the nanocomposite substrates to support osteogenic differentiation.

Innovative magnetic scaffolds for orthopedic tissue engineering

The use of magnetism in tissue engineering is a very promising approach, in fact magnetic scaffolds are able not only to support tissue regeneration, but they can be activated and work like a magnet attracting functionalized magnetic nanoparticles (MNPs) injected close to the scaffold enhancing tissue regeneration. This study aimed to assess the in vivo biocompatibility and osteointegrative properties of novel magnetic scaffolds. Two hydroxyapatite/collagen (70/30 wt %) magnetic scaffolds were magnetized with two different techniques: direct nucleation of biomimetic phase and superparamagnetic nanoparticles (MNPs) on self-assembling collagen fibers (MAG-A) and scaffold impregnation in ferro-fluid solution (MAG-B). Magnetic scaffolds were implanted in rabbit distal femoral epiphysis and tibial mid-diaphysis. Histopathological screening showed no inflammatory reaction due to MNPs. Significantly higher bone healing rate (ΔBHR) results were observed in MAG-A in comparison to MAG-B. Significant differences were also found between experimental times with an increase in ΔBHR from 2 to 4 weeks for both scaffolds in trabecular bone, while only for MAG-B (23%, p < 0.05) in cortical bone. The proposed magnetic scaffolds seem to be promising for magnetic guiding in orthopedic tissue engineering applications and they will be suitable to treat also several pathologies in regenerative medicine area.

Bioplasty for vertebral fractures: preliminary results of a pre-clinical study on goats using autologous modified skin fibroblasts

The debate is still ongoing about the long term effects of the mininvasive vertebral augmentation techniques and their usefulness in treating more complex cases where a bone inducing effect more than a merely bone substitution would be suitable, such as the vertebral fractures in young patients. We previously developed a clinically relevant gene therapy approach using modified dermal fibroblasts for inducing bone healing and bone formation in different animal models. The aim of this study is to show the feasibility of a minimally invasive percutaneous intrasomatic ex vivo gene therapy approach to treat thoracolumbar vertebral fractures and anterior column bone defects in a goat model.

A conceptually new type of bio-hybrid scaffold for bone regeneration

Magnetic bio-hybrid porous scaffolds have been synthesized, nucleating nano-apatite in situ on self-assembling collagen, in the presence of magnetite nano-particles. The magnetic phase acted as a sort of cross-linking agent for the collagen, inducing a chemico-physical-mechanical stabilization of the material and allowing us to control the porosity network of the scaffold. Gradients of bio-mineralization and magnetization were also developed for osteochondral application. The good potentiality of the material as a biomedical device, able to offer assistance to bone regeneration through scaffold reloading with specific factors guided by an external magnetic field, has been preliminarily investigated. Up to now the proof of this concept has been realized through in vitro assessments.

A novel route in bone tissue engineering: magnetic biomimetic scaffolds

In recent years, interest in tissue engineering and its solutions has increased considerably. In particular, scaffolds have become fundamental tools in bone graft substitution and are used in combination with a variety of bio-agents. However, a long-standing problem in the use of these conventional scaffolds lies in the impossibility of re-loading the scaffold with the bio-agents after implantation. This work introduces the magnetic scaffold as a conceptually new solution. The magnetic scaffold is able, via magnetic driving, to attract and take up in vivo growth factors, stem cells or other bio-agents bound to magnetic particles. The authors succeeded in developing a simple and inexpensive technique able to transform standard commercial scaffolds made of hydroxyapatite and collagen in magnetic scaffolds. This innovative process involves dip-coating of the scaffolds in aqueous ferrofluids containing iron oxide nanoparticles coated with various biopolymers. After dip-coating, the nanoparticles are integrated into the structure of the scaffolds, providing the latter with magnetization values as high as 15 emu g(-)(1) at 10 kOe. These values are suitable for generating magnetic gradients, enabling magnetic guiding in the vicinity and inside the scaffold. The magnetic scaffolds do not suffer from any structural damage during the process, maintaining their specific porosity and shape. Moreover, they do not release magnetic particles under a constant flow of simulated body fluids over a period of 8 days. Finally, preliminary studies indicate the ability of the magnetic scaffolds to support adhesion and proliferation of human bone marrow stem cells in vitro. Hence, this new type of scaffold is a valuable candidate for tissue engineering applications, featuring a novel magnetic guiding option.

Ex vivo-transduced autologous skin fibroblasts expressing human Lim mineralization protein-3 efficiently form new bone in animal models

Local gene transfer of the human Lim mineralization protein (LMP), a novel intracellular positive regulator of the osteoblast differentiation program, can induce efficient bone formation in rodents. To develop a clinically relevant gene therapy approach to facilitate bone healing, we have used primary dermal fibroblasts transduced ex vivo with Ad.LMP-3 and seeded on a hydroxyapatite/collagen matrix prior to autologous implantation. Here, we demonstrate that genetically modified autologous dermal fibroblasts expressing Ad.LMP-3 are able to induce ectopic bone formation following implantation of the matrix into mouse triceps and paravertebral muscles. Moreover, implantation of the Ad.LMP-3-modified dermal fibroblasts into a rat mandibular bone critical size defect model results in efficient healing, as determined by X-rays, histology and three-dimensional microcomputed tomography (3DmuCT). These results demonstrate the effectiveness of the non-secreted intracellular osteogenic factor LMP-3 in inducing bone formation in vivo. Moreover, the utilization of autologous dermal fibroblasts implanted on a biomaterial represents a promising approach for possible future clinical applications aimed at inducing new bone formation.

Accuracy of breath tests using low doses of 13C-urea to diagnose Helicobacter pylori infection: a randomised controlled trial

BACKGROUND

The 13C-urea breath test (UBT) for detecting Helicobacter pylori infection is a non-invasive method based on the organism's urease activity. Since its first description, the method has been extensively modified. However, only the dose of 13C-urea and the measurement equipment are directly related to the cost of the test.

AIMS

(1) To assess the diagnostic accuracy before eradication therapy of three UBTs using 25, 15, and 10 mg of 13C-urea, respectively; and (2) to determine diagnostic performance in the post-eradication setting showing the highest values for sensitivity and specificity with the lowest dose of 13C-urea.

METHODS

Three hundred consecutive patients were randomised to be tested with one of the three UBTs. All patients underwent upper endoscopy with biopsies. A total of 222 more patients were enrolled to evaluate the second aim. Infected patients were offered treatment and asked to return 4-6 weeks after the end of therapy to perform endoscopic follow up and to carry out 13C-UBT.

RESULTS

In the pretreatment setting, 13C-UBT 25 mg had a sensitivity of 100% (95% confidence interval (CI) 91.8-100) and a specificity of 100% (95% CI 93.7-100); 13C-UBT 15 mg had a sensitivity of 96.1% (95% CI 86.8-98.9) and a specificity of 100% (95% CI 92.6-100); and 13C-UBT 10 mg had a sensitivity of 89.1% (95% CI 77-95.3) and a specificity of 100% (95% CI 93.3-100). As the test with the best performance and the lowest dose of 13C-urea was 13C-UBT 15 mg, it was evaluated after treatment, reporting a sensitivity of 100% (95% CI 79.6-100) and a specificity of 98.9% (95% CI 94.3-99.8).

DISCUSSION

UBTs using 25 and 15 mg of 13C-urea were both accurate in the diagnosis of H pylori infection in untreated patients. 13C-UBT 15 mg was also accurate for follow up of patients after treatment.

A 10-day levofloxacin-based triple therapy in patients who have failed two eradication courses

BACKGROUND

A standard third-line treatment is lacking, and European guidelines recommend performing culture in these patients. However, the use of this procedure as 'routine practice' is definitively not feasible.

AIM

To evaluate the eradication rate of a 10-day levofloxacin-based triple therapy in patients who have failed two eradication courses for Helicobacter pylori.

METHODS

A total of 151 patients with persistent Helicobacter pylori infection after two treatments were studied. Patients were considered positive if two of three endoscopic tests were positive. Susceptibility testing was also performed. Patients received a standard dose of proton-pump inhibitors twice daily, levofloxacin 250 mg twice daily and amoxicillin 1 g twice daily, for 10 days. Endoscopic follow-up was carried out 4-6 weeks after the end of eradication therapy.

RESULTS

About 76% (95% CI: 68.8-82.3), and 85% (95% CI: 77.5-89.7) of patients were eradicated according to intention-to-treat and per-protocol analysis, respectively. Eradication rates of the strains showed as 92% (95% CI: 83.2-96.7) of those resistant to both metronidazole and clarithromycin but susceptible to levofloxacin.

CONCLUSIONS

In patients who failed previous regimens, the 10-day levofloxacin-based triple therapy is safe and effective, allowing eradication in almost 80% of the patients.

HA/alginate hybrid composites prepared through bio-inspired nucleation

Poorly crystalline apatite has been directly nucleated on self-assembling alginate chains by neutralization synthesis to obtain a biomimetic artificial bone-like composite. It has been observed that in preparing HA/alginate composites, Ca2+ ions present on the apatitic surface cross-link the alginate chains to produce a material with different morphology and thermal stability, both functions of the HA/alginate weight ratio. In vitro tests were performed on different samples in terms of both the HA/alginate ratio and synthesis temperature. All the samples were cultured for seven days with MG63 osteoblast-like cells and then underwent morphological and biochemical analyses (MTT and ALP tests). Scaffolds showed a different solubility into the culture media, which was related to the temperature of synthesis and to the HA/alginate ratio. All our data confirm the ability of the tested materials to favour cell growth and to maintain their osteoblastic functionality, at least during the examined period.

High-resolution 3D scaffold model for engineered tissue fabrication using a rapid prototyping technique

Rapid prototyping, automatic image processing (computer-aided design (CAD)) and computer-aided manufacturing techniques are opening new and interesting prospects for medical devices and tissue engineering, especially for hard tissues such as bone. The development of a bone high-resolution scaffold prototype using these techniques is described. The results testify to the fidelity existing between microtomographic reconstruction and CAD. Furthermore, stereolithographic manufacturing of this scaffold, which possesses a high degree of similarity to the starting model as monitored by morphological evaluations (mean diameter 569 +/- 147 microm), represents a promising result for regenerative medicine applications.

From biomimetic apatites to biologically inspired composites

Hydroxyapatite is an elective material for bone substitution. In this outline of our recent activity the crucial role of nanostructured ceramics in the design and preparation of ceramic scaffolds will be described, focussing on our more recent interest in biomimetic apatites, in particular apatites containing HPO42- CO32- and Mg2+ which are similar to the mineral component of bone. The paper describes such nanostructured products and, in particular, innovative synthetic techniques capable of yielding powders with higher reactivity and bioactivity. However, so far the characteristics of artificial bone tissues have been shown to be very different from those of natural bone, mainly because of the absence of the peculiar self-organizing interaction between apatites and the protein component. This causes modification of the structure of apatites and of the features of the overall composite forming human bone tissue. Therefore, attempts to mimic the features and structure of natural bone tissue, leading toward so-called bio-inspired materials, will be speculated upon. New techniques used to reproduce a composite in which a nanosize blade-like crystal of hydroxyapatite (HA) grows in contact with self-assembling fibres of natural polymer will be presented. In this specific case, the amazing ability of biological systems to store and process information at the molecular level, nucleating nanosize apatites (bio-inspired material), is exploited.

A rapid immunochromatographic assay for Helicobacter pylori in stool before and after treatment

BACKGROUND

Current guidelines recommend non-invasive testing and treatment of young dyspeptic patients without alarm symptoms.

AIM

To evaluate the accuracy of a new rapid immunochromatographic stool test to diagnose Helicobacter pylori infection before and after treatment compared with a gold standard.

METHODS

Prospective, single-blind study, performed in a tertiary care hospital. A total of 303 consecutive dyspeptic patients underwent endoscopy with multiple biopsies. Infected patients were offered a treatment and invited to come back 4-6 weeks after the end of therapy to repeat the endoscopy. Patients were also asked to provide a stool sample before and after therapy.

RESULTS

About 149 patients were H. pylori infected. The sensitivity and specificity before treatment were 91.3 and 93.5%; after treatment 92 and 100%. The likelihood ratios were robust enough to produce significant changes from pretest to post-test probability both in pre-treatment (LR+ = 14, LR- = 0.093) and post-treatment (LR+ = 19.6, LR- = 0.095).

CONCLUSIONS

The novel immunochromatographic stool test is fast, easy to perform and provides good differentiation between positive and negative results. It might become a rapid near patients test easily performed in the doctor office.

Porous phosphate-gelatine composite as bone graft with drug delivery function

The design and synthesis of porous phosphate-gelatine composite implant which mimicks the structure of natural bone and has drug delivery function is proposed. Gelatine reproducing the proteinaceous part of bone was cross-linked in order to modulate its solubility in the physiologic fluids. The kinetic of gelatine release from ceramic matrix was also evaluated as model of the release of any therapeutic compound which can be loaded into gelatine.

Non-invasive techniques for the diagnosis of Helicobacter pylori infection

Helicobacter pylori infection can be diagnosed by invasive techniques requiring endoscopy and biopsy (histologic examination, culture, polymerase chain reaction), and non-invasive techniques (serology, urea breath test, urine or blood, detection of H. pylori antigen in stool specimen). However, recent studies have demonstrated that a strategy of 'testing and treating' for H. pylori in uninvestigated, young (<50 years), dyspeptic patients in primary care is safe and reduces the need for endoscopy. Indeed, a number of clinical guidelines recommend non-invasive testing in dyspeptic patients followed by treatment of H. pylori in primary care based on clinical and economic analyses. Several non-invasive tests are currently available on the market. The choice depends on the clinical circumstances, the likelihood ratio of positive and negative tests, the cost-effectiveness of the testing strategy, and, finally, the availability of the tests. Nevertheless, two non-invasive tests are commonly used: the urea breath test, and the stool antigen test.

Review article: diagnosis and treatment of Helicobacter: a 2002 updated review

The year 2002 saw advances on many fronts in the study of Helicobacter and gastroduodenal disease. Several studies have confirmed endoscopy as a valuable management procedure with confirmation of the diagnostic utility of the rapid urease test and the description of a new formulation of the test, which is more rapid in giving a result. Serology has been re-confirmed as a useful investigation in selected populations. Some commercial kits for near patient testing have also been assessed and although generally regarded as less accurate than laboratory based tests some have shown acceptable accuracy. The recent exciting development in diagnostic serology is the availability of the faecal antigen test; further studies have confirmed its usefulness as recommended screening tests. There have been several studies demonstrating that a test and treat policy has a significant patient benefit, both economic and medical, although there is some doubt if eradication of Helicobacter leads to regression of atrophy and metaplasia. However, in low Helicobacter-prevalence areas the test and treat policy is being challenged as an effective management strategy. Further studies have shown that compliance with treatment regimens is an important determinant of successful eradication. Finally several new eradication regimens have been reported particularly for use in patients who have had previous unsuccessful eradication attempts.

The clinical role of cytochrome p450 genotypes in Helicobacter pylori management

OBJECTIVE

The aim of this pharmacogenomics study was to investigate the influence of different cytochrome P450 (CYP) genotypes in Helicobacter pylori eradication therapy.

METHOD

The study involved 143 consecutive Italian Caucasian patients with H. pylori infection diagnosed and treated with 1-wk triple therapy according to European Helicobacter Pylori Study Group guidelines. Using human genomic DNA, CYP2C19 (*2 and *3) and CYP3A4 alleles (*1B, *2, and *3) were evaluated by polymerase chain reaction-restriction fragment length polymorphism assays and confirmed by sequencing the amplicons.

RESULT

According to the endoscopy-based gold standard, 93 patients achieved H. pylori eradication. Regarding CYP2C19 genotype, the 50 patients who remained infected were all homozygous or heterozygous extensive metabolizers (homEM or hetEM). Carriers of homEM fared significantly less well than those of hetEM; homEM genotype was also predictive of failure at univariate/multivariate analysis. Carriers of CYP3A4 polymorphisms achieved favorable eradication rates similar to patients bearing CYP2C19. All four patients with single CYP3A4*2 polymorphism achieved eradication, and only 29% (5/17) of all CYP3A4*1B carriers did not achieve eradication. All nine patients carrying CYP3A4 polymorphisms in the CYP2C19 hetEM subgroup were cured, suggesting the possibility of a positive synergism between CYP3A4 and CYP2C19.

CONCLUSIONS

This first pharmacogenomics study on the influence of different CYP genotypes on H. pylori therapy suggests that, as in Asian populations, CYP2C19 genotype patterns are probably also relevant in Caucasians receiving H. pylori eradication regimens that include omeprazole. The possibility of a favorable drug interaction mediated by CYP2C19 and CYP3A4 requires investigation.

A rapid, low-dose, 13C-urea tablet for the detection of Helicobacter pylori infection before and after treatment

BACKGROUND

A new urea breath test (UBT) has been described which uses a tablet formulation of 13C-urea with citric acid and allows breath sampling to be performed as early as 10 min after ingestion of the tablet.

AIM

To assess the diagnostic accuracy of tablet-based 13C-UBTs (50 and 100 mg 13C-urea) before and after Helicobacter pylori eradication treatment, compared with an endoscopy gold standard and a conventional 13C-UBT (75 mg 13C-urea).

METHODS

Two hundred dyspeptic patients underwent endoscopy, followed by tablet-based 13C-UBTs (50 and 100 mg 13C-urea) and a conventional 13C-UBT (75 mg 13C-urea). H. pylori-infected patients were prescribed treatment and asked to return 4-6 weeks after the end of therapy for repeat endoscopy and 13C-UBTs.

RESULTS

One hundred and thirteen patients were infected with H. pylori. The sensitivity and specificity of the conventional 13C-UBT were both 100%; the sensitivity and specificity of the 100-mg tablet-based 13C-UBT were 100% and 98.85%, respectively. For the 50-mg tablet-based 13C-UBT, cut-off values of the difference over baseline of between 1.65 and 3.15 provided a sensitivity and specificity of 100%. At follow-up, the sensitivity and specificity of the conventional and 100-mg tablet-based 13C-UBTs were both 100%. For the 50-mg tablet-based 13C-UBT, cut-off values of the difference over baseline of between 1.49 and 1.56 gave a sensitivity and specificity of 100%.

CONCLUSIONS

New 10-min 13C-UBTs using tablet formulations of 13C-urea with citric acid are reliable for the assessment of H. pylori status pre- and post-treatment.

High eradication rates of Helicobacter pylori with a new sequential treatment

BACKGROUND

Eradication rates of Helicobacter pylori with standard triple therapy are disappointing, and studies from several countries confirm this poor performance.

AIM

To assess the eradication rate of a new sequential treatment regimen compared with conventional triple therapy for the eradication of H. pylori infection.

METHODS

One thousand and forty-nine dyspeptic patients were studied prospectively. H. pylori-infected patients were randomized to receive 10-day sequential therapy [rabeprazole (40 mg daily) plus amoxicillin (1 g twice daily) for the first 5 days, followed by rabeprazole (20 mg), clarithromycin (500 mg) and tinidazole (500 mg) twice daily for the remaining 5 days] or standard 7-day therapy [corrected] [rabeprazole (20 mg), clarithromycin (500 mg) and amoxicillin (1 g) twice daily]. H. pylori status was assessed by histology, rapid urease test and 13C-urea breath test at baseline and 6 weeks or more after completion of treatment.

RESULTS

Higher eradication rates were found with the sequential regimen compared to the standard regimen (intention-to-treat: 92% vs. 74%, P < 0.0001; per protocol: 95% vs. 77%, P < 0.0001). Higher eradication rates were also seen in patients with peptic ulcer disease and non-ulcer dyspepsia. In both treatments, compliance was similar (> 90%), as was the rate of side-effects, which were mild.

CONCLUSIONS

This 10-day sequential treatment regimen achieves high eradication rates in peptic ulcer disease and non-ulcer dyspepsia.

Review article: Helicobacter pylori infection from pathogenesis to treatment--a critical reappraisal

The main areas of this review are Helicobacter pylori and disease pathogenesis; the relationship of H. pylori to lower gastrointestinal diseases, liver disease and extra-gastrointestinal conditions; the relationship of H. pylori to gastro-oesophageal reflux disease; infection in the very young and very old; diagnostic techniques; and management of H. pylori infections with particular emphasis on eradication regimens and antibiotic resistance.

Review article: the transmission of Helicobacter pylori from stomach to stomach

The mode of transmission of Helicobacter pylori is largely unknown and is a matter of circumstantial evidence and speculation rather than fact. However, the principle evidence is of two sorts: the epidemiological data, providing evidence of possible risk factors associated with transmission, and the identification of potential sources from which H. pylori could be acquired. Evidence exists for several potential sources of infection and several possible modes of transmission, and it is feasible that the transmission of H. pylori varies according to the cultural and demographic circumstances. However, the most likely recognized source for H. pylori is the human stomach, although it is not known by what route the organism is transmitted to the stomach. Evidence suggests close personal contact is important and that acquisition occurs mainly in childhood. This article reviews the evidence for the source of infection and the route of transmission of H. pylori.

Porosity-graded hydroxyapatite ceramics to replace natural bone

Porous hydroxyapatite HA bodies were prepared with an aim to simulate bone tissue morphology. By varying the characteristics of starting HA powders and the impregnation strategy of cellulosic sponges with rheologically optimized slurries, a wide range of physico-chemical and mechanical properties of the porous ceramics can be obtained. The samples were characterized microstructurally, by density and porosimetry and by mechanical strength. Cylindrical specimens exhibiting a porosity gradient showed a promising behaviour after implantation in rabbits' femur: newly formed bone grew in tight contact with the ceramic in a very short time, no modified cells are induced and bone tissue fills even the inner pores.

Incidence and causes of non-invasive mechanical ventilation failure after initial success

BACKGROUND

The rate of failure of non-invasive mechanical ventilation (NIMV) in patients with chronic obstructive pulmonary disease (COPD) with acute respiratory insufficiency ranges from 5% to 40%. Most of the studies report an incidence of "late failure" (after >48 hours of NIMV) of about 10-20%. The recognition of this subset of patients is critical because prolonged application of NIMV may unduly delay the time of intubation.

METHODS

In this multicentre study the primary aims were to assess the rate of "late NIMV failure" and possible associated predictive factors; secondary aims of the study were evaluation of the best ventilatory strategy in this subset of patients and their outcomes in and out of hospital. The study was performed in two respiratory intensive care units (ICUs) on patients with COPD admitted with an episode of hypercapnic respiratory failure (mean (SD) pH 7.23 (0.07), PaCO(2) 85.3 (15.8) mm Hg).

RESULTS

One hundred and thirty seven patients initially responded to NIMV in terms of objective (arterial blood gas tensions) and subjective improvement. After 8.4 (2.8) days of NIMV 31 patients (23%; 95% confidence interval (CI) 18 to 33) experienced a new episode of acute respiratory failure while still ventilated. The occurrence of "late NIMV failure" was significantly associated with functional limitations (ADL scale) before admission to the respiratory ICU, the presence of medical complications (particularly hyperglycaemia), and a lower pH on admission. Depending on their willingness or not to be intubated, the patients received invasive ventilation (n=19) or "more aggressive" (more hours/day) NIMV (n=12). Eleven (92%) of those in this latter subgroup died while in the respiratory ICU compared with 10 (53%) of the patients receiving invasive ventilation. The overall 90 day mortality was 21% and, after discharge from hospital, was similar in the "late NIMV failure" group and in patients who did not experience a second episode of acute respiratory failure.

CONCLUSIONS

The chance of COPD patients with acute respiratory failure having a second episode of acute respiratory failure after an initial (first 48 hours) successful response to NIMV is about 20%. This event is more likely to occur in patients with more severe functional and clinical disease who have more complications at the time of admission to the ICU. These patients have a very poor in-hospital prognosis, especially if NIMV is continued rather than prompt initiation of invasive ventilation.

Routine use of external cephalic version in three hospitals

BACKGROUND

External cephalic version has been advocated as a safe alternative to vaginal breech delivery or cesarean birth. The purpose of this study was to determine the efficacy of routine use of external cephalic version at 36 weeks or more of gestation in three different levels of hospitals.

METHODS

External cephalic version was performed on 923 women with a single breech fetus at three hospitals in Italy. The procedure was attempted with a tocolytic agent for uterine relaxation and with no maternal analgesia. The version technique adopted was the "forward roll."

RESULTS

Version was successfully performed on 579 fetuses (62.7%); each hospital had a similar success rate, and 56.9 percent of the women delivered vaginally. The procedure was more successful in multiparas and in women with an incomplete type of breech, polyhydramnios, and posterior localization of the placenta. Vaginal bleeding was experienced by 14 women; eight cesarean sections were performed for suspected abruptio placentae, confirmed in four cases. Two cephalic-turned fetuses experienced an episode of persistent bradycardia and were turned again to breech; in five cases a nonstress test recorded after the version showed repeated variable decelerations and in one case a cesarean section was performed. Neonatal outcomes were good in 922 infants. A fracture of the femur attributable to the version was observed in one newborn.

CONCLUSIONS

External cephalic version is effective in reducing the number of cesarean deliveries in term breech infants in different obstetric settings, with no major neonatal adverse outcomes.

Tumor progression is accompanied by significant changes in the levels of expression of polyamine metabolism regulatory genes and clusterin (sulfated glycoprotein 2) in human prostate cancer specimens

Using Northern blotting, the expression levels of the genes for polyamine metabolism regulatory proteins and clusterin have been measured in a series of 23 human prostate cancers (CaPs) dissected from radical prostatectomy specimens. Patient matched, nontumor tissue was dissected from benign areas of the gland. The results indicate that transcripts encoding ornithine decarboxylase (ODC), ODC antizyme, adenosylmethionine decarboxylase, and spermidine/spermine N1-acetyltransferase (SSAT) were significantly higher, whereas clusterin (sulfated glycoprotein 2) mRNA was significantly lower in tumors compared with the benign tissue. All mRNA levels were compared with those of histone H3 and growth arrest-specific gene 1, markers of cell proliferation and cell quiescence, respectively, and glyceraldehyde 3-phosphate dehydrogenase, a housekeeping gene. In poorly differentiated and locally invasive CaPs and in tumors with unfavorable prognosis or total prostate-specific antigen (PSA) levels > 10.0 ng/ml at diagnosis, an overall increase in the levels of H3 mRNA and a decrease in growth arrest-specific gene 1 mRNA was detected, indicative of higher proliferation activity, whereas the differences in expression levels for the polyamine metabolism and clusterin genes were higher. ODC and SSAT changes were positively correlated in normal tissue but not in high-grade cancer, whereas ODC antizyme and SSAT changes were positively correlated in more malignant CaPs but not in normal tissue. Tumor classification based on the changes in expression levels of all of the genes studied could be correlated to differentiation grade and local invasiveness classification systems in 72.2 and 83.3% of the cases, respectively. In a 1-year follow-up period, three patients whose CaPs ranked as less aggressive according to clinical staging, but classified as advanced cancers with the proposed molecular classification, showed increases in total PSA levels, indicative of tumor relapse. Thus, molecular classification, based on gene expression, may enhance the available prognostic tools for prostate tumors.

Reliability study of the European appropriateness evaluation protocol

OBJECTIVE

To help to co-ordinate and harmonize research on utilization review in Europe, the US Appropriateness Evaluation Protocol (f¿EP) was adapted for use in the European setting. The aim of this paper is to assess the reliability of the European version of the AEP (EU-AEP).

DESIGN

Nineteen English-language medical records were reviewed by a physician reviewer from each of six participating countries: Austria, France, Italy, Spain, Switzerland and the UK. Each of the six reviewers was asked to assess the appropriateness of the 19 admissions and 31 hospitalization days (19 admission days and 12 randomly selected days of hospital stay, excluding days of discharge) using the revised review instrument. To evaluate inter-rater reliability, the kappa statistic was used to measure overall and pair-wise agreement for the assessment of appropriateness of admission and of day of care, respectively.

RESULTS

For admission, the overall kappa statistic among the six reviewers was 0.64, with kappa values for each pair of reviewers in the range 0.46-0.86. For day of care, the kappa was 0.59, with pair-wise kappa coefficients in the range 0.25-0.95.

CONCLUSION

The observed agreement could be considered substantial, especially if the fact that medical records were hand-written in a language native to only one of the reviewers is considered. Besides all the study limitations, this finding provides at least preliminary support for the application of the EU-AEP as a reliable instrument in the European setting, including application in comparative studies involving two or more countries.

Changes in cesarean delivery in an Italian university hospital, 1982-1996: a comparison with the national trend

BACKGROUND

The cesarean delivery rate in Italy rose dramatically from the mid-1970s to 1996, accounting for 22.4 percent of all deliveries in the last national survey. The aim of this study was to analyze the results of the clinical practice of a new staff in the Department of Obstetrics and Gynecology of a university hospital, with particular focus on the application of common protocols. The rates of cesarean sections and perinatal mortality were chosen as parameters for good clinical practice and were compared with national data.

METHODS

A new staff assumed the obstetric management at the hospital in 1982. Standardized protocols were implemented for all major indications for cesarean delivery (repeat cesarean section, dystocia, breech presentation, fetal distress).

RESULTS

The rate of cesarean deliveries decreased from 26.4 to 12 percent and remained stable during the past decade. Other operative modalities were used for approximately 1.5 percent of deliveries. The perinatal mortality decreased to 0.5 percent in 1994. To confirm whether or not staff followed common protocols, a review of three years (1994-1996) showed a fairly stable frequency of cesarean sections on different days and nights during the week, confirming the homogeneity of obstetric management.

CONCLUSIONS

Our data showed that, irrespective of the local situation and of the risks of litigation, a significant reduction of cesarean sections can be achieved in a tertiary care center without detrimental effects on newborns, especially in a teaching hospital where residents are trained. Despite national trends suggesting the contrary, some women may choose to deliver in an obstetrics department with better care and fewer operative procedures than in hospitals with higher cesarean delivery rates.

A European version of the Appropriateness Evaluation Protocol. Goals and presentation. The BIOMED I Group on Appropriateness of Hospital Use

This paper describes the development and testing of a European version of the Appropriateness Evaluation Protocol (AEP). It stemmed from the original U.S. version and the multiple adaptations and modifications made previously and separately by researchers in European countries. The group was particularly concerned with developing a common list of reasons for inappropriate admissions and days of stay, since the principal goal was to enable an understanding of inappropriate hospital use and potential solutions within local health and social care systems. Developing a common EU-AEP included several steps. First, each national instrument was translated from the national language to English. These back translations were compared with each other and with the US-AEP. A working group analyzed the content of the lists of reasons published in the literature and proposed a novel conceptual approach. On the basis of workshop discussions, a draft of a common European version was circulated to each participant for agreement. In the EU-AEP, the clinical criteria for the appropriateness of admission include 10 related to patient condition and five to clinical services. The criteria for the appropriateness of days of care include 10 covering medical services, six for life support/nursing services, and eight related to patient condition. The proposed core list of reasons of inappropriateness distinguish clearly between two concepts: a) the level of care required by the patient; and b) the reason why this level of care was not used. The first list would thus refer to the nature of resources and facilities required, while the second would focus more on the efficient organization of those resources. A validated European tool to assess inappropriate hospital admissions and hospital days of stay and their causes might be used to assess the need for resources for inpatient care as well as for outpatient care. Assessing the reasons for inadequacies might lead also to the examination of organizational questions. Finally, a common tool allows comparisons between countries concerning the frequency of inappropriate admissions and days of stay and their reasons in relation to the different organizations of health care across Europe.

Sintering and characterization of HA and TCP bioceramics with control of their strength and phase purity

HA and beta-TCP-based ceramics were prepared using commercial powders. Powder characteristics were defined and the processing parameters studied, aimed at the production of samples with improved microstructural and mechanical properties. The behaviour of HA powder subjected to various thermal treatments was investigated in order to control the formation of secondary phases (alpha- and beta-TCP) during sintering. The optimal thermal treatment required to prepare pure beta-TCP powder from the precursors (HA and DCP) was determined and the sintering method required to prepare fully dense beta-TCP completely free from alpha-form, was identified. Translucent hot-pressed beta-TCP ceramics with potential applications in aesthetic restorative prostheses were prepared and characterized. The interval of existence of alpha-TCP and alpha-TCP as secondary products was also defined. Crystallographic analysis was carried out on the imperfectly known low-temperature alpha-TCP phase, and a proper monoclinic unit cell determined.

Influence of antimalarials chloroquine, quinine, primaquine and mepacrine on the evolution of Ehrlich ascites tumour

Substances like imidazoles, benzimidazoles and also quinolines, whose chemical structure includes a heterocyclic nitrogen, are known to interfere with the microsomal oxidation and, in some cases, with the metabolism of drugs. Since chloroquine and primaquine exert this effect in vivo and in vitro, we studied the influence of other antimalarials (quinine and mepacrine) in mice with induced Ehrlich ascites tumour (EAT) to find out whether variations in oxygen consumption affected the course of the disease. In vitro data, obtained by a polarographic technique, indicate that primaquine and, in particular, mepacrine increase EAT-cell oxygen consumption, while in vivo data, obtained in mice injected with an inoculum of about 1 x 10(6) tumour cells per mouse, show that both drugs, but notably mepacrine, accelerate tumour growth, as monitored by Cox's statistical method for body weight, and lead to earlier death. In cases of existing neoplasia, therefore, the potentially toxic effects of certain antimalarials must be borne in mind.

Appropriateness of hospital use: an overview of Italian studies

This paper reports on the general features and findings of 11 studies conducted in Italy on appropriateness of hospital admission and days of stay using the Appropriateness Evaluation Protocol (AEP). Studies have been grouped for presentation in two categories. The first comprises six heterogeneous studies illustrating different ways of targeting the use of the AEP: two used it to assess appropriateness of admission in an emergency room setting, two measured appropriateness of days of stay in patients with AIDS and nosocomial infections and finally two others evaluated hospital days in a group of elderly patients and "before and after" the institution of a domiciliary nursing service, respectively. The second group comprises five more homogeneous utilization review studies aimed at assessing inappropriateness of admissions and days of stay in medical/surgical departments of large hospitals in northern Italy. Besides detecting a substantial amount of inappropriateness in admission (range = 25-38%) and days of stay (range = 28-49%) this latter group of studies suggests that delays in execution and reporting of laboratory investigations, unavailability of operating rooms and delays due to difficulties in transferring patients to long-term care facilities are the most common causes of inappropriate days of stay. Despite the differences in their objectives, design and methods of sampling, these studies indicate that an explicit, diagnosis-independent and standardized instrument such as the AEP can help to uncover a substantial amount of the potentially avoidable use of hospital resources in the Italian context.

Influence of glycyrrhizin on the evolution and respiration of Ehrlich ascites tumour cells

It has been demonstrated that 18 alpha-glycyrrhetinic acid, 18 beta-glycyrrhetinic acid and glycyrrhizin effectively inhibit the inception and growth of skin tumours. Moreover, glycyrrhizin and its aglycone act on the growth and differentiation of mouse melanoma cells in culture. In this study we investigated the effect of glycyrrhizin, 18 alpha- and 18 beta-glycyrrhetinic acids on the evolution of Ehrlich ascites tumour in mice. A prolonged glycyrrhizin treatment proved to be effective in modifying the animals' survival pattern.

Quantitation of HIV-1 p24 antibody expressed as relative binding capacity p24 antigen (p24 RBC) in infants born to HIV-1 seropositive mothers: correlation of this serological marker with the HIV-1 maternal antibody course and p24 antigenemia detection

The antibody content to HIV-1 p24 Ag expressed as relative binding capacity to the target antigen (p24 RBC) was retrospectively quantified in serum samples from 20 HIV-1-uninfected infants born to HIV-1 seropositive mothers. p24 RBC values quantified at birth were included either in a low (0-20%) or high (80-100%) range of values, classified as group A (11 infants) and group B (9 infants), respectively. The course of maternal antibodies to HIV-1 antigens p17, p24, p31, gp41, p51, p66, gp120, and gp160 was studied in each group. A substantial difference in the amount and subsequently in the decline of maternal antibodies to gag proteins p17, p24, and p55 and to pol proteins p51 and p66 was observed in the two infant groups in contrast with a similar content and decline of the remaining antibodies. In 7 HIV-1-infected infants of whom 4 resembled infant group A and 3 infant group B for p24 RBC values, a relationship appeared between p24 antibody decline and p24 antigenemia detection.

Prevalence rates of gallstone disease in Italy. The Chianciano population study

The prevalence of gallstone disease and associated factors in the entire population of subjects aged 15-65 years born and resident in Chianciano Terme (Siena - Tuscany) was examined in the years 1985 and 1986. The investigation included gallbladder ultrasonography, administration of a questionnaire on personal and family history, physical examination and blood chemistry. A total of 1809 subjects (attendance rate 87.7%) participated in the study. Personal history and physical examination showed that Chianciano inhabitants have a low prevalence of obesity (4.3%) and only 4.4% of the female population had more than two pregnancies. Overall prevalence of gallstone disease (cholecystectomy+cholelithiasis) was 5.9% (3.7% for males and 8.4% for females). Age standardized relative risk of gallstone disease for females was 2.25 (95% confidence limits = 1.68-2.68). Prevalence of cholelithiasis was 3.5% (2.7% for males and 4.2% for females). Prevalence of gallstone disease increased with increasing age in both sexes, being extremely low in the age interval of 15-29 years (0.25%). The overall gallstones/cholecystectomy ratio was found to be lower (1:1) in females than in males (2.7:1). Although subjects with gallstones reported more frequently biliary colics and non-specific dyspeptic symptoms, the diagnostic power of all symptoms in identifying cholelithiasis was very poor due to low sensitivity. Only one third of subjects with gallstones was aware of having the disease. Age, obesity and number of pregnancies were positively associated with gallstone disease in univariate analyses. The association with obesity and parity disappeared in multivariate analysis. Blood lipids and glucose were not associated with the disease both in univariate and multivariate analyses.(ABSTRACT TRUNCATED AT 250 WORDS)

Identification of homogeneous geographical areas of mortality for tumours from cluster analysis

This paper attempts to demonstrate the utility of cluster analysis as a descriptive method of studying mortality in epidemiology. In order to verify which algorithms of clustering best fit the data structure, the method of cophenetic correlation was implemented. Furthermore the probabilistic algorithm proposed by Beale was used to assess the partition. The results show the presence of some striking clusters between Local Sanitary Units of the Emilia Romagna Region for four types of tumour in men.