Exendin-4 Prevents Memory Loss and Neuronal Death in Rats with Sporadic Alzheimer-Like Disease

This study investigated the neuroprotective effects of exendin-4 (EXE-4), an analog of the glucagon-like peptide 1 receptor (GLP-1R) on memory and on the neuronal populations that constitute the hippocampus of rats submitted to a sporadic dementia of Alzheimer's type (SDAT). Male Wistar rats received streptozotocin (STZ icv, 3 mg/kg diluted in aCFS, 5 µl/ventricle) and were treated for 21 days with EXE-4 (10 µg/kg, ip; saline as the vehicle). Four groups were formed: vehicle, EXE-4, STZ, and STZ + EXE-4. The groups were submitted to Y-Maze (YM), object recognition (ORT), and object displacement tasks (ODT) to assess learning and memory. The brains were used for immunohistochemical and immunofluorescent techniques with antibodies to NeuN, cleaved caspase-3 (CC3), PCNA, doublecortin (DCX), synaptophysin (SYP), and insulin receptor (IR). STZ worsened spatial memory in the YMT, as well as short-term (STM) and long-term (LTM) memories in the ORT and ODT, respectively. EXE-4 protected against memory impairment in STZ animals. STZ reduced mature neuron density (NeuN) and increased cell apoptosis (CC3) in the DG, CA1, and CA3. EXE-4 protected against neuronal death in all regions. EXE-4 increased PCNA+ cells in all regions of the hippocampus, and STZ attenuated this effect. STZ reduced neurogenesis in DG per se as well as synaptogenesis induced by EXE-4. EXE-4 increased immunoreactivity to IR in the CA1. From these findings, EXE-4 showed a beneficial effect on hippocampal pyramidal and granular neurons in the SDAT showing anti-apoptotic properties and promoting cell proliferation. In parallel, EXE-4 preserved the memory of SDAT rats. EXE-4 appears to enhance synapses at CA3 and DG. In conclusion, these data indicate that agonists to GLP-1R have a beneficial effect on hippocampal neurons in AD.

Identifying gaps in the cascade of care for latent TB infection in a low-incidence setting

BACKGROUND: The End TB Strategy calls for the global scale-up of treatment for latent TB infection (LTBI). We aimed to evaluate a nurse-led care programme for LTBI by identifying gaps in the care cascade in a low-incidence TB setting.METHODS: We included people at risk of TB over a 15-year period. We define three main outcomes in the LTBI care cascade: 1) attendance at the first appointment, 2) completion of the evaluation process, and 3) completion of treatment.RESULTS: We identified 6,126 individuals (2,369 TB contacts, 1,749 biological therapy candidates, and 2,008 transplant candidates). Overall, 5,938 (96.9%) attended, 5,872/5,938 (98.9%) completed the evaluation and 1,624/1,847 (87.9%) completed treatment. Pre-biological (aOR 2.32, 95% CI 1.54-3.49) and pre-transplant (aOR 1.82, 95% CI 1.20-2.76) candidates were more likely to attend the first appointment, while age was associated with completing the evaluation process (aOR 1.02, 95% CI 1.003-1.04). Female sex (aOR 1.47, 95% CI 1.08-1.99) was associated with completing the treatment.CONCLUSION: Successful assessment and treatment of LTBI is achievable when delivered as a part of a comprehensive, nurse-led, patient-centred programme in specialist TB clinics.

Why foodborne and waterborne parasites are important for veterinarians

Parasites, including helminths and protists, are pathogens responsible for waterborne and foodborne illnesses in both developed and developing countries. Their global incidence is difficult to estimate, but the World Health Organization (WHO) has indicated the global disease burden of 11 waterborne and foodborne parasitic diseases, is responsible for causing over 407 million illnesses resulting in an estimated of 94 K deaths and 11 million disability-adjusted life years (DALYs). Nevertheless, compared with bacteria and viruses, parasites are often overlooked as etiological agents of foodborne or waterborne disease; this is due to a variety of reasons, including the difficulty of their identification in environmental matrices and because many have a prolonged period between infection and symptoms, making it difficult to implicate infection vehicles. This Special Issue comprises 17 articles that include the more significant waterborne and foodborne parasites of zoonotic importance due to their relevance, with all groups of parasites (protist, cestodes, trematodes, and nematodes) being represented. Each chapter covers relevant aspects regarding -the importance of the parasite in food and water, including an overview of outbreaks where relevant, information on fundamental epidemiological aspects such as transmission, lifecycle and host range, clinical aspects such as pathogenesis, diagnosis and treatment, a summary of prospects for control in water or the food chain, and, finally, providing the authors' opinions regarding future research or studies required to improve control of transmission to people via food or water.

Rifabutin for treating tuberculosis in solid organ transplant recipients: A retrospective observational study and literature review

BACKGROUND

The treatment of tuberculosis (TB) in solid organ transplant (SOT) recipients is challenging owing to interactions between rifampin and immunosuppressive drugs. Rifabutin, a rifamycin with excellent activity against Mycobacterium tuberculosis and that induces cytochrome p450 less, may facilitate treatment. We report our experience with rifabutin for treating TB in SOT recipients and review the available literature.

METHODS

A retrospective observational study of all SOT recipients with TB between January 2000 and December 2019. The clinical characteristics and outcomes of patients treated with and without rifabutin-containing regimens were compared and a literature review was conducted.

RESULTS

We included 31 SOT recipients with TB, among whom 22 (71%) were men and the median age was 62 years (interquartile range 50-20). There were no significant differences between patients treated with rifabutin (n = 12), rifampin (n = 14), and non-rifamycins (n = 5) in clinical cure rates (83.3%, 64.3%, and 100%, respectively; P = .21), side effects (25%, 37.5%, and 20%, respectively; P = .74), or mortality (16.7%, 35.7%, and 0%, respectively; P = .21). Only one patient, treated with rifampin, suffered graft rejection. The literature review identified 59 SOT recipients with TB treated with rifabutin-containing regimens from 8 publications. Overall, the clinical cure, graft rejection, and mortality rates were 93.2%, 5.1%, and 6.8%, respectively.

CONCLUSIONS

Rifabutin-containing regimens offer a reliable alternative to rifampin when treating TB in SOT recipients.

Customised multiphasic nucleus/annulus scaffold for intervertebral disc repair/regeneration

Background: In the case of a degenerated intervertebral disc (IVD), even though spinal fusion has provided good short-term clinical results, an alteration of the spine stability has been demonstrated by long-term studies. In this context, different designs of IVD prostheses have been proposed as alternative to spinal fusion. However, over the past few years, much of the recent research has been devoted to IVD tissue engineering, even if several limitations related to the complex structure of IVD are still presented.Purpose/Aim: Accordingly, the aim of the current paper was to develop a strategy in designing customised multiphasic nucleus/annulus scaffolds for IVD tissue engineering, benefiting from the great potential of reverse engineering, additive manufacturing and gels technology.Materials and Methods: The device consisted of a customised additive-manufactured poly(ε-caprolactone) scaffold with tailored architectural features as annulus and a cell-laden collagen-low molecular weight hyaluronic acid-based material as nucleus with specific rheological and functional properties. To this aim, injectability and viscoelastic properties of the hydrogel were analyzed. Furthermore, a mechanical and biological characterization of cell-laden multiphasic nucleus/annulus scaffold was performed.Results and Conclusions: Analyses on the developed devices demonstrated appropriate viscoelastic and mechanical properties. As evidenced by rheological tests, the hydrogel showed a shear-thinning behaviour, supporting the possibility to inject the material. The mechanical characterization highlighted a compressive modulus which falls in the range of lumbar discs, with the typical initial J-shaped stress-strain curve of natural IVDs. Furthermore, preliminary biological tests showed that human mesenchymal stem cells were viable over the culture period.

Increasing isolation of rapidly growing mycobacteria in a low-incidence setting of environmental mycobacteria, 1994-2015

To determine trends in incidence and clinical relevance of rapidly growing mycobacteria (RGM) in a low-prevalence region of non-tuberculous mycobacteria. We retrospectively identified all patients with RGM-positive cultures between January 1994 and December 2015. Trends in incidence, clinical significance, and outcomes were assessed. One hundred and forty patients had RGM-positive cultures (116 respiratory and 24 extra-respiratory sources). The incidence of RGM isolates increased steadily from 2003 (0.34 per 100,000) to 2015 (1.73 per 100,000), with an average annual increase of 8.3%. Thirty-two patients (22.9%) had clinical disease, which trended to cluster in the second half of the study period. A positive acid-fast bacilli smear (odds ratio [OR] 97.7, 95 % CI 13.8-689.4), the presence of extra-respiratory isolates (OR 19.4, 95 % CI 5.2-72.7), and female gender (OR 5.9, 95 % CI 1.9-19.1) were independently associated with clinical disease. Cure rates were 73.3 and 87.5% for pulmonary and extra-pulmonary disease respectively. Although the burden of disease remains low, the presence of RGM isolates is increasing in our geographical setting. Whether this rise will be sustained over time and will coincide with an increase in clinical disease, or whether it is merely a cycle in the poorly understood epidemiological behaviour of environmental mycobacteria, will be seen in the near future.

Surface functionalization superparamagnetic nanoparticles conjugated with thermoresponsive poly(epsilon-lysine) dendrons tethered with carboxybetaine for the mild hyperthermia-controlled delivery of VEGF

Vascular endothelial growth factor (VEGF) is the growth factor responsible for the triggering of angiogenesis, the process of blood vessel formation supporting the long-term viability of any repaired or regenerated tissue. As the growth factor is effective only when concentration gradients are generated, new shuttles need to be developed that ensure both the control of gradients at the site of tissue repair and the release of VEGF at physiological levels. Magnetic hyperthermia is the production of heat induced by magnetic materials through their exposure to an external oscillating magnetic field. In this paper, magnetic nanoparticles capable of generating controllable hyperthermia were functionalised with hyperbranched poly(epsilon-lysine) peptides integrating in their core parallel thermoresponsive elastin-like peptide sequences and presenting an uppermost branching generation tethered by the zwitterionic amino acid carboxybetaine. The results show that these functionalised magnetic nanoparticles avidly bind VEGF and release it only upon generation of mild-hyperthermic pulses generated by oscillating magnetic filed. The VEGF release occurred in a temperature range at which the elastin-like peptides collapse. It is proposed that, through the application of an external magnetic field, these magnetic carriers could generated gradients of VEGF in vivo and allow its tuned delivery in a number of clinical applications.

STATEMENT OF SIGNIFICANCE

The present paper for the first time reveals the possibility to control the delivery of VEGF through mild hyperthermia stimuli generated by a oscillating magnetic field. To this purpose, magnetic nanoparticles of high size homogeneity and coated with a thin coating of poly(acrylic acid) were functionalised with a novel class of poly(epsilon lysine) dendrimers integrating in their structure a thermoresponsive amino acid sequence mimicking elastin and exposing at high density a zwitterionic modified amino acid, the carboxybetaine, known to be able to bind macromolecules. Physicochemical and biochemical characterisation elegantly show the link between the thermal properties of the nanoparticles and of the dendrimer change of conformation and how this enable the release of VEGF at temperature values compatible with the growth factor stability.

Chemical-Physical Characterization and in vitro Preliminary Biological Assessment of Hyaluronic Acid Benzyl Ester-Hydroxyapatite Composite

HYAFF®11 is a biocompatible, biodegradable benzyl ester of hyaluronic acid. However, in order to use it for orthopedic application, its mechanical performance needs to be improved. In this study, a novel composite based on HYAFF®11 polymer matrix reinforced with hydroxylapatite (HA) has been developed. Its advantage is having a similar component of the mineral phase of bone resulting in favorable osteoconductive properties. The present study has examined the compressive mechanical and surface chemical-physical properties of the novel HYAFF®11-HA composite. Preliminary biological investigations, including pH and cytotoxicity studies of the material extracts, have also been performed using an in vitro primary human osteoblast-like cell model. Moreover, protein, especially fibronectin adsorption has been investigated following incubation in culture medium and human plasma. The results show a grainy surface topography composed mainly of C, P, and Ca, with a Ca/P atomic ratio indicating HA on the composite surface. Mechanical analysis shows an improvement of the compressive properties of HYAFF11 matrix, both in the dry and swollen states, with values in the range of that of spongy bone. No cytotoxic effects and no inhibition of cell proliferation have been observed in the presence of the material extracts with pH values within acceptable ranges for cell vitality. Protein studies reveal a similar pattern, but a higher amount of fibronectin following incubation in human plasma when compared with culture medium. The results show that the novel HYAFF®11-HA composite shows a great potential for application in orthopedic fields, especially as vertebral trabecular bone substitute.

Silver-doped self-assembling di-phenylalanine hydrogels as wound dressing biomaterials

Chronic and acute wounds can be quickly contaminated and infected by microorganisms such as bacteria, multi-resistant organisms or fungi. The introduction of silver as anti-microbial agent into wound management has widely been demonstrated to be effective and contribute to wound healing. As a consequence, many approaches and different materials have been employed to synthesize antibacterial silver-hydrogels. In this work the introduction of silver particles into the fibrillar structure of self-assembling aromatic di-phenylalanine derivatives modified with aromatic groups such as 9-fluorenylmethoxycarbonyl is proposed to produce antibacterial wound dressings. Hydrogels doped with increasing amounts of silver were tested and adopted to modify flax textiles. The influence of silver on the structure of hydrogels was studied using light and confocal microscopy, while SEM-EDX allowed the characterization of the hydrogel coating on the surface of the textile substrates as well as the identification and distribution of silver nanoparticles. The antibacterial potential of the treated flax was demonstrated through microbiological tests on Staphylococcus aureus. The combination of the physico-chemical and anti-bacterial properties, together with the ease of preparation of these biomaterials, fulfils the requirement of clinically-effective wound dressings.

Therapeutic doses of nonsteroidal anti-inflammatory drugs inhibit osteosarcoma MG-63 osteoblast-like cells maturation, viability, and biomineralization potential

Nonsteroidal anti-inflammatory drugs (NSAIDs) are frequently used to reduce pain and inflammation. However, their effect on bone metabolisms is not well known, and results in the literature are contradictory. The present study focusses on the effect of dexketoprofen, ketorolac, metamizole, and acetylsalicylic acid, at therapeutic doses, on different biochemical and phenotypic pathways in human osteoblast-like cells. Osteoblasts (MG-63 cell line) were incubated in culture medium with 1-10 μM of dexketoprofen, ketorolac, metamizole, and acetylsalicylic acid. Flow cytometry was used to study antigenic profile and phagocytic activity. The osteoblastic differentiation was evaluated by mineralization and synthesis of collagen fibers by microscopy and alkaline phosphatase activity (ALP) by spectrophotometric assay. Short-term treatment with therapeutic doses of NSAIDs modulated differentiation, antigenic profile, and phagocyte activity of osteoblast-like cells. The treatment reduced ALP synthesis and matrix mineralization. However, nonsignificant differences were observed on collagen syntheses after treatments. The percentage of CD54 expression was increased with all treatments. CD80, CD86, and HLA-DR showed a decreased expression, which depended on NSAID and the dose applied. The treatments also decreased phagocyte activity in this cellular population. The results of this paper provide evidences that NSAIDs inhibit the osteoblast differentiation process thus reducing their ability to produce new bone mineralized extracellular matrix.

Osteoconductive phosphoserine-modified poly({varepsilon}-lysine) dendrons: synthesis, titanium oxide surface functionalization and response of osteoblast-like cell lines

The lack of direct bonding between the surface of an implant and the mineralized bony tissue is among the main causes of aseptic loosening in titanium-based implants. Surface etching and ceramic coatings have led to improved osteointegration, but their clinical performance is still limited either by partial bonding or by coating delamination. In this work, a solid-phase synthesis method has been optimized to produce poly(ε-lysine) dendrons, the outermost branching generation of which is functionalized by phosphoserine (PS), a known catalyst of the biomineralization process. The dendrons were deposited onto etched titanium oxide surfaces as a near-to-monolayer film able to induce the formation of a homogeneous calcium phosphate phase in a simulated body fluid over 3 days. The dendron films also stimulated MG63 and SAOS-2 osteoblast-like cells to proliferate at a rate significantly higher than etched titanium, with SAOS-2 also showing a higher degree of differentiation over 14 days. PS-tethered dendron films were not affected by various sterilization methods and UV treatment appeared to improve the cell substrate potential of these films, thus suggesting their potential as a surface functionalization method for bone implants.

Novel soybean/gelatine-based bioactive and injectable hydroxyapatite foam: material properties and cell response

Despite their known osteoconductivity, clinical use of calcium phosphate cements is limited both by their relatively slow rate of resorption and by rheological properties incompatible with injectability. Bone in-growth and material resorption have been improved by the development of porous calcium phosphate cements. However, injectable formulations have so far only been obtained through the addition of relatively toxic surfactants. The present work describes the response of osteoblasts to a novel injectable foamed bone cement based on a composite formulation including the bioactive foaming agents soybean and gelatine. The foaming properties of both defatted soybean and gelatine gels were exploited to develop a self-hardening soy/gelatine/hydroxyapatite composite foam able to retain porosity upon injection. After setting, the foamed paste produced a calcium-deficient hydroxyapatite scaffold, showing good injectability and cohesion as well as interconnected porosity after injection. The intrinsic bioactivity of soybean and gelatine was shown to favour osteoblast adhesion and growth. These findings suggest that injectable, porous and bioactive calcium phosphate cements can be produced for bone regeneration through minimally invasive surgery.

Treatment completion in latent tuberculosis infection at specialist tuberculosis units in Spain

SETTING

Treatment of latent tuberculosis infection (LTBI) is essential for tuberculosis (TB) control in low-prevalence countries. However, the long treatment duration and adverse events frequently result in suboptimal treatment completion.

OBJECTIVE

To determine completion rates of LTBI treatment and to identify risk factors for non-completion of treatment.

DESIGN

Retrospective, observational cohort study.

METHODS

All non-human immunodeficiency virus infected adults who started treatment for LTBI at two specialist TB units in Spain between January 2004 and March 2007 were included. Those who discontinued treatment due to toxicity were excluded.

RESULTS

Of 599 people who started on treatment, 484 (80.8%, 95%CI 77.5-83.8) completed it. Age <36 years (OR 0.33, 95%CI 0.30-0.76, P = 0.001), male sex (OR 0.58, 95%CI 0.37-0.92, P = 0.02), immigrant status <5 years of residence (OR 0.21, 95%CI 0.12-0.37, P < 0.001) and the presence of social risk factors (OR 0.21, 95%CI 0.11-0.39, P < 0.001) were associated with lower rates of treatment completion. Short treatment regimens were not associated with better treatment completion compared with isoniazid for 6-9 months (OR 0.89, 95%CI 0.45-1.80, P = 0.76).

CONCLUSIONS

Overall, completion rates of LTBI treatment in specialist TB units are good. Nevertheless, counselling should be strengthened and new strategies to enhance adherence should be sought for recent immigrants and for people in unfavourable social situations.

Nanoparticles of a different source induce different patterns of activation in key biochemical and cellular components of the host response

Nanoparticulate materials are produced by industrial processing or engineered for specific biomedical applications. In both cases, their contact with the human body may lead to adverse reactions. Most of the published papers so far have focused on the cytotoxic effects of nanoparticles (NPs). Instead, the present in vitro study investigates the effect of different types of NP on key components of the host response such as clot formation and the inflammatory cells. The different NPs were pre-conditioned with platelet-rich human plasma for 30 min and then incubated with the blood mononuclear cells for 20 hours. The potential of the different NPs to induce clot formation, platelet activation and monocyte/macrophage differentiation was assessed by morphological analysis, immunocytochemistry and biochemical assays. The data showed that nanoparticulate materials based on antimony, silver and nickel were capable of promoting the polymerization of fibrin and the aggregation and fragmentation of platelets, leading to a moderately activated monocyte phenotype. This process was more pronounced in the case of antimony- and silver-based NPs that share a similar size and round-shaped morphology. Conversely, NPs of cobalt, titanium and iron appeared to stimulate cells to acquire a macrophage phenotype able to secrete higher levels of tumour necrosis factor alpha, a pro-inflammatory cytokine. Therefore, the present study provides clear indications about the subtle and adverse effects that the invasion of these materials may produce in the cardiovascular system and in vital organs.

Cell behaviour on phospholipids-coated surfaces

Effective integration of orthopedic biomaterials requires the rapid formation of the inorganic mineral phase during the first hours of implantation and the subsequent adhesion and proliferation of the osteoblasts. It has recently been demonstrated that phosphatidylserine-rich phospholipid coatings can induce a fast mineralisation of titanium implant surfaces on incubation in simulated body fluids. The aim of this work was to investigate the biocompatibility of these coatings in terms of cytotoxicity and ability to support osteoblast adhesion and activity. Cytotoxicity and cell adhesion to uncoated titanium, calcified phospholipid-coated titanium and HA-coated titanium was assessed using fibroblasts and osteoblast-like cells. The synthesis of type I collagen by osteoblast-like cells cultured on the calcified-phospholipid coatings was also comparable to that observed for osteoblast-like cells cultured on the titanium and HA-Ti surfaces.The results suggest that the fast mineralization of the phospholipid matrix, obtained in vitro by its pre-treatment in a SBF, exposes the cells to an environment similar to that present in the bone during its natural formation that allow cells to adhere, proliferate and produce proteins fundamental for bone growth. The biocompatibility of these phospholipid-based coatings, in combination with their ability to initiate rapid mineralisation, provides a promising material that could in vivo create bone cell interactions and bone integration.

In vivo assessment of the osteointegrative potential of phosphatidylserine-based coatings

The successful implantation of titanium-based implants for orthopaedic and dental applications is often hindered because of their mobility, which arises because of a lack of direct binding of the metal surface to the mineral phase of the surrounding bone. Ceramic coatings, although ensuring the integration of the implant within the tissue, are unstable and carry risks of delamination and of failure. Recently, a novel biomimetic approach has been developed where porous titanium implants are coated with calcium-binding phospholipids able to catalyse the nucleation of discrete apatite crystals after only 30 min incubation in simulated body fluids. The present work assesses the osteointegrative potential of this new class of coatings in an in vivo rabbit model and compares its performance with those of bare porous titanium and hydroxyapatite-coated titanium. The data obtained show that phosphatidylserine-based coatings, whilst resorbing, drive the growing bone into apposition with the metal surface. This is in contrast to the case of bare titanium.

Incidence and molecular typing of Mycobacterium kansasii in a defined geographical area in Catalonia, Spain

A retrospective population-based study was conducted between January 1990 and December 1998 to investigate the incidence of Mycobacterium kansasji disease and the heterogeneity of the isolates in a well-defined geographical area in Catalonia, Spain. A total of 136 patients were identified. Overall incidence and incidence in AIDS patients was 1.5 (95% CI 1.2-1.8) and 1089.6 (95% CI 689-1330) cases/100,000 persons per year respectively, which is comparable to that reported from most of other geographical areas. Surprisingly, although 7 subtypes of M. kansasii have been consistently reported, in the present study 91 of the 93 isolates (97.8%) tested for genotype were subtype I, regardless of HIV status of the patients. In conclusion, the high rate of infection observed in the AIDS population contributes significantly to the burden of the M. kansasii disease in our area. M. kansasii disease in our geographical area was almost exclusively caused by subtype I regardless of HIV status.

Factors inducing in-stent restenosis: an in-vitro model

In-stent restenosis is caused by the proliferation of the smooth muscle cells (SMCs) following a host response towards the implanted device. However, the precise biochemical and cellular mechanisms are still not completely understood. In this paper, the behaviour of SMCs has been investigated by an in vitro model where the cells were stimulated by platelet derived growth factor (PDGF) on tissue-like substrates as well as on biomaterials such as stainless steel (St) and diamond-like carbon (DLC)-coated St. The results demonstrated that SMCs have a completely different adhesion mode on St and become particularly prone to proliferation and pro-inflammatory cytokine secretion under PDGF stimulus. This would suggest that restenosis may caused by the accidental contact of the SMC with the St substrate under an inflammatory insult.

Group B Streptococcal Disease in Nonpregnant Adults: Incidence, Clinical Characteristics, and Outcome

A retrospective review of 150 cases of group B streptococcal disease in nonpregnant adults over an 8-year period was performed in a single tertiary-care teaching hospital to determine the incidence, clinical spectrum, and outcome of the disease. Incidence increased from 0.53 cases per 1,000 admissions in the 1993-1994 period to 0.96 cases per 1,000 admissions in 1999-2000 (P=0.013, chi-square test for trend). Bacteremia also increased from 0.15 to 0.42 cases per 1,000 admissions over the same period of time (P=0.005, chi-square test for trend). The mean age of the patients was 61.4 years, and 92% had at least one underlying disease. Bacteremia was detected in 60.9% of patients in whom blood cultures were performed. Fourteen (9.3%) patients died. Factors independently associated with an increased risk of dying were shock at diagnosis (OR, 23.96; 95%CI, 3.44-166.57; P=0.001) and cancer (OR, 4.96; 95%CI, 1.43-17.20; P=0.012). Group B streptococcal disease in nonpregnant adults is on the rise in the hospital investigated, particularly in persons with underlying conditions. The clinical spectrum of the disease ranges from localized to severe bacteremic infections. Shock at diagnosis and cancer are factors independently associated with a higher fatality rate.

Identification of assemblage A Giardia in white-tailed deer

Fecal samples were collected from hunter-killed white-tailed deer (Odocoileus virginianus) during a managed hunt in a central Maryland county. Fecal samples were cleaned of debris and concentrated by CsCl density gradient centrifugation and stained with MerIFluor reagents. Stained samples were examined by fluorescent microscopy for the presence of Giardia sp. cysts. One of 26 samples was found to be positive for Giardia sp. Polymerase chain reaction amplification using primers directed to the beta-giardin and TPI genes identified the same sample as the only positive one. Sequencing of the beta-giardin and TPI genes revealed that the Giardia sp. belonged to assemblage A, a genotype infectious for humans and also reported in a small percentage of cattle. This is the first report of assemblage A Giardia sp. in deer and suggests that deer could be a potential source of infectious cysts for humans and cattle.

Mycobacterium kansasii disease among patients infected with human immunodeficiency virus type 1: improved prognosis in the era of highly active antiretroviral therapy

OBJECTIVE

To investigate changes in survival and trends in occurrence of Mycobacterium kansasii disease in HIV-infected patients after implementation of highly active antiretroviral therapy (HAART).

METHODS

Retrospective analysis of cases of M. kansasii infection diagnosed at the Hospital Universitari de Bellvitge, Barcelona, Spain, between 1991 and 2002. As HAART was introduced at the end of 1996, the study period was divided into periods A (1991-1996) and B (1997-2002).

RESULTS

During the study period 44 cases of active M. kansasii disease were identified. The median number of cases per year was five in period A and two in period B. There were no differences in clinical presentation between the two periods. The estimated 24-month survival rate was 16% for period A and 65% for period B (P = 0.0065). Both HAART (RR 11.2; 95% CI 3.8-33.9; P < 0.001) and non-disseminated disease (RR 2.45; 95% CI 1.1-5.2; P = 0.02) were independently associated with longer survival.

CONCLUSIONS

A substantial improvement in the outcome and a fall in new cases of M. kansasii in patients infected with HIV-1 was observed in our institution, mainly as a consequence of the introduction of effective antiretroviral therapy. Antiretroviral treatment should be encouraged in these patients, even in cases of severe immunosuppression.

Hydrothane(R) interactions with biological components: a comparison with Chronoflex(R)

The interaction of a glycol-containing polyurethane, Hydrothane(R), was assessed with respect to protein adsorption and cell and bacterial adhesion. The results obtained were compared with those from a second polyurethane, Chronoflex(R). Dynamic contact angle (DCA) and protein adsorption studies indicated that the overall hydrophilic nature of Hydrothane in physiological environment was affected by the possible presence of hydrophobic domains still exposed at the surface after wetting. Indeed, despite the high degree of hydrophilicity in an aqueous environment, a stronger protein binding was evidenced on Hydrothane when the two serum- and urine-conditioned polyurethane surfaces were selectively washed by isopropanol/water mixtures of increasing concentrations. Furthermore, immunoblotting of the serum proteins adsorbed on Hydrothane demonstrated the presence on its surface of proteins able to establish hydrophobic interactions such as human serum albumin (HSA) and á 1-microglobulin ( á 1-m). The C3 fragment of complement showed an immunoblotting profile different from the control serum suggesting an activation of this fragment. The adhesion of fibroblasts and Pseudomonas aeruginosa on the surface of the two materials was evaluated and the data were related to protein adsorption. In both cases Hydrothane showed levels of adhesion of eukaryotic and prokaryotic cells significantly lower than Chronoflex. These data were related to the absence of a significant binding of proteins such as fibronectin bringing amino acid receptor sequences in their structure. (Journal of Applied Biomaterials & Biomechanics 2003; 1: 67-75).

Contamination of Atlantic coast commercial shellfish with Cryptosporidium

Shellfish (oysters and/or clams) were obtained from 37 commercial harvesting sites in 13 Atlantic coast states from Maine to Florida and one site in New Brunswick, Canada. Gill washings from each of 25 shellfish at each site were examined by immunofluorescence microscopy (IFA) for oocysts of Cryptosporidium. Gill washings from another 25 shellfish at each site were grouped into five pools of five shellfish each. DNA from each pool was utilized for PCR and genotyping. Oocysts were found in 3.7% of 925 oysters and clams examined by IFA in shellfish from New Brunswick and 11 of 13 states. Cryptosporidium DNA was detected by PCR in 35.2% of 185 pools. Cryptosporidium parvum genotypes 1 and 2, and Cryptosporidium meleagridis,all of which have been identified in infected humans, were identified at 37.8% of the sites. Gill washings from every site were tested for the presence of infectious oocysts by biological assay in neonatal BALB/c mice but no mice were found infected, suggesting that either the oocysts were no longer infectious or infections in mice were below the level of detection. Collectively, these findings indicate that Cryptosporidium species, indicative of pollution from human and animal feces and potentially infectious for humans, were found in commercial shellfish from 64.9% of sites examined along the Atlantic coast by either microscopy or molecular testing. Previous reports link periods of high rainfall with the elevated numbers of pathogen contaminated shellfish. Because shellfish in the present study were examined during a period of exceptionally low precipitation, the data are thought to underestimate the number of Cryptosporidium contaminated shellfish likely to be found during periods of normal or above normal precipitation.

A novel biomimetic treatment for an improved osteointegration of titanium

Direct osteointegration of titanium and titanium alloys implants is one of the main goals of biomaterials research for dental and orthopedic applications. Chemical, mechanical or biological treatments are investigated searching for fast and durable implant to bone bonding. The aim of the present work is to assess the in vitro mineralisation capabilities and to investigate the mechanical and physico-chemical properties of a new biomimetic treatment on titanium. The new surface treatment was obtained using Anodic Spark Deposition technique, and consists of a first ASD treatment performed in solutions containing phosphate ions followed by a second ASD treatment in a solution rich in calcium ions. The resulting surface is finally treated by alkali etching. The physio-chemical and mechanical properties of this material are analyzed and the mineralization potential is considered by surface analysis after soaking it in different solutions of simulated body fluid (SBF). The developed biomimetic treatment was then compared to other treatments from the literature. The proposed treatment was found to possess a very high mineralization capaci-ty, that makes its application very interesting in terms of speed and strength of direct implant osteointegration. (Journal of Ap-plied Biomaterials & Biomechanics 2003; 1: 33-42).

First epidemic of echovirus 16 meningitis in Cuba

From April to September 2000, an epidemic of aseptic meningitis spread throughout Cuba, with 16,943 reported cases. Virologic studies identified echovirus 16 as the cause of this epidemic. This is the first reported isolate of echovirus 16 from patients with viral meningitis in Cuba.

In vitro evaluation of the inflammatory potential of the silk fibroin

Silk fibroin membranes recently have been suggested as matrices for biomedical applications, such as guided tissue regeneration and burn wound dressings. The aim of this study was to evaluate the inflammatory potential of fibroin films and to compare the fibroin films with two model materials with completely different physico-chemical properties: poly(styrene) and poly(2-hydroxyethyl methacrylate). Fibroin bound lower levels of fibrinogen than did the two synthetic polymers while the same amounts of adsorbed human plasma complement fragment C3 and IgG were detected. Studies of the binding strength of C3 to fibroin, evaluated by a novel experimental procedure, indicated the occurrence of strong hydrophobic interactions at the interface. The activation of the mononuclear cells by fibroin, measured as interleukin 1beta production, was lower than the reference materials. Adhesion experiments showed the ability of the macrophages to adhere to fibroin by filopodia without a complete spreading of the cells. The results achieved in this study demonstrate that the interactions of fibroin with the humoral components of the inflammatory system were comparable with those of the two model surfaces while the degree of activation and adhesion of the immunocompetent cells appeared more limited.

Collagen-bound alpha1-microglobulin in normal and healed tissues and its effect on immunocompetent cells

The mechanisms devoted to the protection of the extracellular matrix collagen from the inflammatory insult are not fully understood. We investigated the presence of the immunosuppressive glycoprotein alpha1-microglobulin in healed tissues such as scars and periprosthetic membranes, comparing them with normal skin. Immunohistochemistry showed that alpha1-microglobulin was mainly present along collagen fibrils and in the epidermis. The presence of this protein was confirmed by Western blot of the tissue homogenates, while ELISA showed lower levels in the healed tissues. In vitro, the purified alpha1-microglobulin bound collagen by a cooperative mechanism and attenuated the collagen-induced activation of the mononuclear cells.

Effect of the urine conditioning film on ureteral stent encrustation and characterization of its protein composition

The goal of this study was to characterize the protein composition of the conditioning film deposited onto the surface of ureteral stents during in vivo implantation and to relate its presence to the precipitation of calcium crystals. The protein pattern of the conditioning film of implanted nonencrusted and encrusted urological stents was assessed by SDS-PAGE and Western blot of the desorbed species. The results obtained highlighted different electrophoresis profiles between nonencrusted and encrusted stents. Western blot showed the ubiquitous presence of albumin, while Tamm-Horsfall Protein and alpha1-microglobulin adsorption was limited to nonencrusted devices. By an in vitro dynamic model in which artificial urine was flowed through the lumen of control and retrieved nonencrusted stents, we demonstrated that the organic layer remarkably enhanced crystal precipitation and aggregation events on the surface.

Changes in the surface conditioning of calcium-salt crystals treated with physiological and alkaline urine

OBJECTIVE

To study, using an in vitro model, the early phases of deposition of urinary components onto the surface of calcium-salt crystals treated with physiological and alkaline urine.

MATERIALS AND METHODS

Calcium carbonate, oxalate and phosphate crystals were incubated in either freshly collected 'physiological' urine (pH 5.5) or with urine at pH 8.0. The surface conditioning was characterized using sodium-dodecyl sulphate-polyacrylamide gel electrophoresis immunoblot profiles of the adsorbed proteins and by Fourier transform infrared spectroscopy. Crystal morphology and aggregation were assessed using scanning electron microscopy.

RESULTS

The patterns of protein adsorption from physiological urine showed the ubiquitous adsorption of bands within 51-86 kDa, while Tamm-Horsfall protein (THP) and alpha 1-microglobulin were found only in calcium oxalate crystals. Less aggregation was detected in calcium oxalate and phosphate crystals treated in urine at pH 5.5, while a new crystalline phase was deposited on calcium carbonate surfaces. Incubation in alkaline urine led to changes in the protein electrophoretic profiles, with a significant variation in the morphology of the inorganic phase only in calcium phosphate crystals.

CONCLUSIONS

The binding of urinary proteins onto crystals depends on the chemistry of the surface and on the physicochemical composition of the urine. THP, albumin, alpha 1-microglobulin and a 20 kDa protein were able to bind calcium crystals under different circumstances. Except for THP, there was no clear relationship between the adsorption of proteins on crystals and the re-arrangement of the inorganic phase.

Changes in serum conditioning profiles of glutaraldehyde-crosslinked collagen sponges after their treatment with calcification inhibitors

The purpose of this study was to evaluate the effects of the calcification inhibitors FeCl3 and sodium dodecyl sulfate (SDS) on the morphology of glutaraldehyde-crosslinked type I collagen sponges and on their serum conditioning. Scanning electron microscopy (SEM) showed that the morphology of the sponges, already modified by glutaraldehyde crosslinking, underwent further changes after treatment of the hydrogels with inhibitors. Coral-like structures were found to branch from the bulk of the material especially in the case of SDS-treated samples. The composition and morphology of the conditioning layers was characterized after 48 h incubation in serum by SDS-polyacrylamide gel electrophoresis-immunoblot of the adsorbed proteins, by energy-dispersive X-ray analysis of the elements (EDX), and by SEM of the conditioned surfaces. All the samples showed the adsorption of proteins with molecular weights ranging from 10 to 203 kD. However, the peculiar adsorption of an approximately 10-kD band (complement C3 fragment) and of fibronectin were detected in the case of glutaraldehyde-crosslinked collagen. On the other hand, glutaraldehyde-crosslinked collagen treated with 0.1M FeCl3 showed the remarkable adsorption of a 29-kD band. The glutaraldehyde-crosslinked hydrogels showed the massive precipitation of crystals on their exposed surfaces, whereas a disordered network structure surrounding the collagen fibrils was found in the case of the samples pretreated with inhibitors. A predominant precipitation of sodium and chloride was detected in all the sponges, although the ratio between the peaks changed from from one hydrogel to another. The results reported in this article clearly indicate that the treatments with SDS and FeCl3 change the surface conditioning of collagen sponges, suggesting a possible role of deposited serum solutes in affecting mineralization processes on bioprosthesis.

Possible role of alpha-1-microglobulin in mediating bacterial attachment to model surfaces

Urine proteins in the molecular weight range of 9-137 kDa deposit to an equal extent from pooled human urine onto glass (12.7 +/- 1.9 micrograms/cm) and polystyrene (11.8 +/- 1.8 micrograms/cm). Selective desorption of the proteins was achieved by washing with water or water/isopropanol mixtures. Irrespective of the washing process, proteins of molecular weight greater than 90 kDa remained associated with both surfaces while water washings alone removed most low molecular weight material. A 29 kDa protein, alpha-1-microglobulin, was removed from glass by water washing but required a 30% (v/v) isopropanol wash to desorb from polystyrene, implying attachment via hydrophobic bonding. The adhesion to polystyrene surfaces of Pseudomonas aeruginosa B4, a clinical isolate from a urinary tract infection (UTI), was strongly associated with the presence of alpha-1-microglobulin, which may be acting as a mediator of bacterial adhesion.

Adsorption of serum alpha-1-microglobulin onto biomaterials

The adsorption of alpha-1-microglobulin (alpha-1-m) from serum to the surface of polymers with different physicochemical properties was investigated. Enzyme-linked immunosorbent assay showed binding of this protein to the surface of polystyrene (PS), polyvinyl chloride (PVC) and a polyurethane, Chronoflex, after water washing, but only trace levels could be detected on two polymethacrylate derivatives, polymethyl methacrylate and poly(2-hydroxyethyl methacrylate). alpha-1-m was selectively desorbed from the five materials by sequential washes of serum-conditioned surfaces with isopropanol solutions at increasing concentrations. The presence of alpha-1-m in the washing supernatants was detected by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). The relative binding strength of alpha-1-m to each surface was evaluated as the isopropanol (IsoPOH) concentration required to desorb the protein from that surface. Analysis of bound proteins by SDS-PAGE conclusively demonstrated the binding of a range of serum proteins, including alpha-1-m, to all polymer systems, but with varying binding strengths. The majority of protein was removed by water washing for the polymethacrylate polymers, while varying concentrations of IsoPOH were required to desorb proteins from PS, PVC and Chronoflex. There was a correlation between the hydrophobic nature of the material, determined by water contact angle measurements, and adsorption of alpha-1-m. Immunoblotting of isopropanol-eluted proteins by alpha-1-m antibodies showed the positive staining of a 29 kDa protein as well as selected bands within a molecular weight range of 40 200 kDa, suggesting the adsorption of this protein as both free and complexed forms. The ability of alpha-1-m to adsorb on to material surfaces and to participate in events relevant to the biocompatibility of a polymer, such as bacterial infection or inflammation control, suggests the need for further characterization of the properties of this protein.

Adhesion of bacteria to stainless steel and silver-coated orthopedic external fixation pins

Bacterial adhesion to silver-coated orthopedic external fixation pins was compared with stainless steel controls in an in vitro study. Using five bacterial isolates from wound infections, the silver coating was found to reduce adhesion for Escherichia coli, Pseudomonas aeruginosa, and two strains of Staphylococcus aureus while the converse applied for Staphylococcus haemolyticus. When placed in human serum, both surfaces were conditioned to a similar extent with serum proteins; this conditioning lead to further reductions in bacterial adhesion, ultimately approaching similar levels for both stainless steel and silver-coated samples.

Adhesion of bacteria to stainless steel and silver-coated orthopedic external fixation pins

Bacterial adhesion to silver-coated orthopedic external fixation pins was compared with stainless steel controls in an in vitro study. Using five bacterial isolates from wound infections, the silver coating was found to reduce adhesion for Escherichia coli, Pseudomonas aeruginosa, and two strains of Staphylococcus aureus while the converse applied for Staphylococcus haemolyticus. When placed in human serum, both surfaces were conditioned to a similar extent with serum proteins; this conditioning lead to further reductions in bacterial adhesion, ultimately approaching similar levels for both stainless steel and silver-coated samples.