Preparation and evaluation of a niosomal delivery system containing G. mangostana extract and study of its anti-Acanthamoeba activity

Garcinia mangostana extract (GME) has severe pharmacokinetic deficiencies and is made up of a variety of bioactive components. GME has proven its anti-Acanthamoeba effectiveness. In this investigation, a GME-loaded niosome was developed to increase its potential therapeutic efficacy. A GME-loaded niosome was prepared by encapsulation in a mixture of span60, cholesterol, and chloroform by the thin film hydration method. The vesicle size, zeta potential, percentage of entrapment efficiency, and stability of GME-loaded niosomes were investigated. The values for GME-loaded niosome size and zeta potential were 404.23 ± 4.59 and -32.03 ± 0.95, respectively. The delivery system enhanced the anti-Acanthamoeba activity, which possessed MIC values of 0.25-4 mg mL-1. In addition, the niosomal formulation decreased the toxicity of GME by 16 times. GME-loaded niosome must be stored at 4 °C, as the quantity of remaining GME encapsulated is greater at this temperature than at room temperature. SEM revealed the damage to the cell membrane caused by trophozoites and cysts, which led to dead cells. In light of the above, it was found that GME-loaded niosomes had better anti-Acanthamoeba activity. The study suggested that GME-loaded niosomes could be used as an alternative to Acanthamoeba's therapeutic effects.

Large polarons in two-dimensional fullerene networks: the crucial role of anisotropy in charge transport

The recent synthesis of a two-dimensional quasi-hexagonal-phase monolayer network of C60 molecules, known as qHPC60, holds significant promise for future semiconductor applications. However, the mechanism behind charge transport in these networks remains unknown. In this study, we developed a Holstein-Peierls Hamiltonian model to investigate charge transport in qHPC60, incorporating both local and non-local electron-phonon couplings. Our computational approach involved identifying suitable semi-empirical parameters to realize the formation of stable polarons in this material. The results unveiled the formation of stable large polarons as the primary carriers in the charge transport throughout qHPC60. To explore polaron transport properties, we conducted dynamic simulations within the picosecond time scale while subjecting the system to an external electric field. Our analysis emphasized the substantial influence of anisotropy on shaping mobile polarons, with an anisotropy coefficient of at least 50%. The polarons exhibited velocities within the acoustic regime ranging from 0.5-1.5 nm ps-1. While these velocities are comparable to those observed in high-end organic molecular crystals, they are considerably lower than those in graphene and conducting polymers. With qHPC60 possessing a semiconducting band gap of approximately 1.6 eV, our findings shed light on its potential application in flat electronics, overcoming the null-gap predicament of graphene.

Acinetobacter baumannii: An overview of emerging multidrug-resistant pathogen

The emergence of infections caused by Acinetobacter baumannii, a multidrug-resistant bacterium, has been a concern worldwide. This bacterium is an important hospitalacquired pathogen that causes several diseases including ventilator-associated pneumonia, bloodstream infections, and meningitis. This study aimed to determine antibioticresistant mechanisms in the pathogenesis of A. baumannii and the alternative treatment strategies against it. The combined actions of outer membrane protein A, formation of a biofilm on biotic and abiotic surfaces, phospholipases C and D, metal homeostatic system, lipopolysaccharides, and verotoxins are relevant for virulence and pathogenesis. A. baumannii resists the broad-spectrum antibiotics by its mechanisms of resistance, such as β-lactamases, efflux pump, aminoglycoside modifying enzymes, permeability changes, and alternation of targets. In an attempt to overcome the resistance mechanisms, plant-derived compounds and a combination of the antibiotics and the plant phytocompounds have been focused. Nanoparticles synthesised with the plant extract have been studied extensively. Furthermore, we projected modern methods, including multi-omics analysis, to study insight into mechanisms of actions of antibiotics. The information suggested that the potential antibiotic mechanisms of A. baumannii could lead to an alternative treatment against A. baumannii infections.

On the mechanical properties and fracture patterns of the nonbenzenoid carbon allotrope (biphenylene network): a reactive molecular dynamics study

Recently, a new two-dimensional carbon allotrope named biphenylene network (BPN) was experimentally realized. The BPN structure consists of four-, six-, and eight-membered rings of sp²-hybridized carbon atoms. In this work, we carried out fully-atomistic reactive (ReaxFF) molecular dynamics simulations to study the mechanical properties and fracture patterns of non-defective and defective (nanocracks) BPN. Results show that, under uniaxial tensile loading, BPN is converted into four distinct morphologies before fracture starts. This conversion process is dependent on the stretching direction. Some of the formed structures contain mainly eight-membered rings, which have different shapes in each morphology. In one of them, a graphitization process occurs before the complete fracture. Importantly, in the presence of nanocracks, no new morphologies are formed. BPN exhibits a distinct fracture process when contrasted to graphene. After the critical strain threshold, the graphene transitions from an elastic to a brittle regime, while BPN can exhibit different inelastic stages. These stages are associated with the appearance of new morphologies. However, BPN shares some of the exceptional graphene properties. BPN Young's modulus and melting point are comparable to graphene, about 1019.4 GPa and 4024 K, respectively.

Can Costus afer be used for co-treatment of COVID-19, its symptoms and comorbidities? A novel approach for combating the pandemic and implications for sub-Saharan Africa

Despite the huge loss of lives and massive disruption of the world economy by the COVID -19 pandemic caused by SARS -CoV-2, scientists are yet to come out with an effective therapeutic against this viral disease . Several vaccines have obtained 'emergency approval ', but difficulties are being faced in the even distribution of vaccines amongst high- and low- income countries . On top of it, comorbidities associated with COVID -19 like diabetes, hypertension and malaria can seriously impede the treatment of the main disease, thus increasing the fatality rate . This is more so in the context of sub -Saharan African and south Asian countries . Our objective was to demonstrate that a single plant containing different phytoconstituents may be used for treatment of COVID -19 and comorbidities . Towards initial selection of a plant, existing scientific literature was scanned for reported relevant traditional uses, phytochemicals and pharmacological activities of a number of plants and their phytoconstituents pertaining to treatment of COVID-19 symptoms and comorbidities. Molecular docking studies were then performed with phytochemicals of the selected plant and SARS-CoV-2 components - Mpro, and spike protein receptor binding domain and hACE2 interface using AutoDock V ina. We showed that crude extracts of an indigenous African plant, Costus afer having traditional antidiabetic and antimalarial uses, has phytochemicals with high binding affinities for Mpro, and /or spike protein receptor binding domain and hACE2 interface; the various phytochemicals with predicted high binding energies include aferoside C, dibutyl phthalate, nerolidol, suginal, and ± -terpinene, making them potential therapeutics for COVID -19. The results suggest that crude extracts and phytochemicals of C. afer can function as a treatment modality for COVID -19 and comorbidities like especially diabetes and malaria .

Potential role of flavonoids against SARS-CoV-2 induced diarrhea

COVID-19, caused by the SARS-CoV-2 virus, can lead to massive inflammation in the gastrointestinal tract causing severe clinical symptoms. SARS-CoV-2 infects lungs after binding its spike proteins with alveolar angiotensin-converting enzyme 2 (ACE2), and it also triggers inflammation in the gastrointestinal tract. SARS-CoV-2 invades the gastrointestinal tract by interacting with Toll-like receptor-4 (TLR4) that induces the expression of ACE2. The influx of ACE2 facilitates cellular binding of more SARS-CoV-2 and causes massive gastrointestinal inflammation leading to diarrhea. Diarrhea prior to COVID-19 infection or COVID-19-induced diarrhea reportedly ends up in a poor prognosis for the patient. Flavonoids are part of traditional remedies for gastrointestinal disorders. Preclinical studies show that flavonoids can prevent infectious diarrhea. Recent studies show flavonoids can inhibit the multiplication of SARS-CoV-2. In combination with vitamin D, flavonoids possibly activate nuclear factor erythroid-derived-2-related factor 2 that downregulates ACE2 expression in cells. We suggest that flavonoids have the potential to prevent SARS-CoV-2 induced diarrhea.

Immuno-modulatory effects of nanoplastics and humic acids in the European seabass (Dicentrarchus labrax)

Pernicious effects of plastic particles, emergent contaminants worldwide, have been described in different species. In teleost species, alterations of immune function after exposure to nanoplastics (NPs) have been reported, but the interaction with cortisol - hypothalamic-pituitary-adrenal (HPI) axis has not yet been explored. Furthermore, the role of dissolved organic matter on the effects of NPs is poorly known. Thus, the aims of this research were to assess if polystyrene NPs (PSNPs) acted as a stressor on juvenile European seabass (Dicentrarchus labrax), interfering with the immune response, as well as to elucidate if humic acids (HA) modulated the potential effects of PSNPs. A short-term exposure to PSNPs and HA elicited an immuno-modulatory response, with an activation of steroidogenic stress-related pathways. An upregulation of anti-inflammatory cytokine (il10, tgfb) and stress-related (mc2r, gr1) transcripts were observed after exposure to HA and PSNPs both individually and in co-exposure. No notable alteration of inflammatory markers was consistently found, which may reflect a protective anti-inflammatory effect of HA in the presence of PSNPs. Nevertheless, there seems to be a more complex interaction between both components. Overall, data show that understanding the interaction of NPs with dissolved organic substances is key to deciphering their environmental risks.

In silico screening of Allium cepa phytochemicals for their binding abilities to SARS and SARS-CoV-2 3C-like protease and COVID-19 human receptor ACE-2

Corona virus SARS-CoV-2-induced viral disease (COVID-19) is a zoonotic disease that was initially transmitted from animals to humans. The virus surfaced towards the end of December 2019 in Wuhan, China where earlier SARS (Severe Acute Respiratory Syndrome) had also surfaced in 2003. Unlike SARS, SARS-CoV-2 (a close relative of the SARS virus) created a pandemic, and as of February 24 2021, caused 112,778,672 infections and 2,499,252 deaths world-wide. Despite the best efforts of scientists, no drugs against COVID-19 are yet in sight; five vaccines have received emergency approval in various countries, but it would be a difficult task to vaccinate twice the world population of 8 billion. The objective of the present study was to evaluate through in silico screening a number of phytochemicals in Allium cepa (onion) regarding their ability to bind to the main protease of COVID-19 known as the 3C-like protease or 3CL^pro, (PDB ID: 6LU7), 3CL^pro of SARS (PDB ID: 3M3V), and human angiotensin converting enzyme-2 (ACE-2), [PDB ID: 1R42], which functions as a receptor for entry of the virus into humans. Molecular docking (blind docking, that is docking not only against any target pocket) were done with the help of AutoDockVina. It was observed that of the twenty-two phytochemicals screened, twelve showed good binding affinities to the main protease of SARS-CoV-2. Surprisingly, the compounds also demonstrated good binding affinities to ACE-2. It is therefore very likely that the binding affinities shown by these compounds against both 3CL^pro and ACE-2 merit further study for their potential use as therapeutic agents.

Probiotics and Amelioration of Rheumatoid Arthritis: Significant Roles of Lactobacillus casei and Lactobacillus acidophilus

Rheumatoid arthritis is a chronic autoimmune disorder that can lead to disability conditions with swollen joints, pain, stiffness, cartilage degradation, and osteoporosis. Genetic, epigenetic, sex-specific factors, smoking, air pollution, food, oral hygiene, periodontitis, Prevotella, and imbalance in the gastrointestinal microbiota are possible sources of the initiation or progression of rheumatoid arthritis, although the detailed mechanisms still need to be elucidated. Probiotics containing Lactobacillus spp. are commonly used as alleviating agents or food supplements to manage diarrhea, dysentery, develop immunity, and maintain general health. The mechanism of action of Lactobacillus spp. against rheumatoid arthritis is still not clearly known to date. In this narrative review, we recapitulate the findings of recent studies to understand the overall pathogenesis of rheumatoid arthritis and the roles of probiotics, particularly L. casei or L. acidophilus, in the management of rheumatoid arthritis in clinical and preclinical studies.

Characterization of lip prints in a Portuguese twins' population

Lip print patterns are referred to as unique to each individual, but controversy exists surrounding twins. In this study, the lip prints of 19 pairs of monozygotic and 47 pairs of dizygotic twins were studied. The left lower lip was photographed and the furrows were classified using Renaud's classification. Results showed the same lip pattern was found only in one monozygotic pair (5.3%) and in 4 dizygotic pairs (8.5%), and no significant statistical differences were found between groups (p > 0.05). In monozygotic twins only type C furrows presence displayed statistical significant differences (p=0.034). As for dizygotic twins, there were statistical significant differences in the frequency of type A (p=0.005) and type G furrows (p=0.018). As for the most common types, both groups displayed a higher prevalence of vertical furrows (type B: 97.4% and 96.8%, type A: 86.8% and 87.2%, in monozygotic and dizygotic, respectively). The least frequent furrow type was type I and type E in monozygotic (2.6% and 5.3%, respectively) and types E, F and I, in dizygotic (6.4%, 7.4%. and 7.4%, respectively). Our results seem to point out that lip print patterns should be useful carefully in twins' identification.

Multiorgan histopathological changes in the juvenile seabream Sparus aurata as a biomarker for zinc oxide particles toxicity

Zinc oxide nanoparticles are widely used in some domains (cosmetics, pharmaceuticals optical devices, and agricultural field) due to their physical, optical, and antimicrobial properties. However, the release of ZnO-NPs into the environment may affect organisms like fish with potential consequences for human health. Histological approaches of the acute effects of these materials on fish are scarce; thus, the present study aimed to investigate the potential toxic effects of acute exposure to ZnO particles in marine environments, by assessing histological changes in the gills, liver, spleen, and muscle of gilthead seabream (Sparus aurata) juveniles. Thus, fish were exposed for 96 h, via water, to 1 mg L-1 of ionic zinc and zinc oxide particles (1.1, 1.2, and 1.4 μm of size). Histological examination revealed gills as the most affected organ, followed by liver, muscle, and spleen. In the gills, histopathological changes included hyperplasia of epithelial cells, fusion of the secondary lamellae, and lifting of the lamellar epithelium with edema. In the liver, lipid vacuolation of several degrees, necrosis of hepatic and pancreatic tissues, blood congestion in sinusoids and hepatoportal vessels, presence of cellular infiltrate, and melano-macrophages diffusion was found. Muscle showed degeneration, atrophy, thickening and necrosis of muscle fibers with edema between them, and presence of melano-macrophages in the muscle layer. Spleen was the less damaged organ, displaying congested blood, white pulp increase/rupture, and bigger and darker melano-macrophage aggregates in the splenic stroma. These results underline that the size of particles plays a determinant role in their potential pernicious effects. A short-term exposure caused major histopathological changes in relevant organs of S. aurata juveniles, possibly affecting their function.

Physical violence against children and adolescents in Recife: a 5-year retrospective study

The aim of the present study was to analyze the prevalence results of physical violence against children and adolescents in a 5-year period in Recife, Brazil. Inter-personal violence is one of the most recognizable forms of child aggression and has become as an imperative public health issue. All violence related forensic reports performed between 2009 and 2013 in the clinical services of the Institute of Legal Medicine Antônio Percivo Cunha were analyzed. Victims were classified according to sex, age, relationship with perpetrator, injuries and year of occurrence. Statistical analysis was performed using the SPSS (version 22.0). Continuous variables were described and when appropriate, frequencies were displayed and compared. The association between variables was evaluated using chi-square and Fisher's exact test. The margin of error for the statistical tests was 5.0%. A total of 9783 occurrences were evaluated, involving mainly male subjects (n=5447, 55.7%). Victims' mean age was 13.9 years, the most common perpetrators were victims' acquaintances (n=2538, 25.9%). Facial injuries were the most frequent affecting a little over a fifth of the total sample (n=3673, 20.1%). These findings support the important role dentists can play in identifying and reporting physical violence against children and adolescents.

Sources and dynamics of fluorescent particles in hospitals

Fluorescent particles can be markers of bioaerosols and are therefore relevant to nosocomial infections. To date, little research has focused on fluorescent particles in occupied indoor environments, particularly hospitals. In this study, we aimed to determine the spatial and temporal variation of fluorescent particles in two large hospitals in Brisbane, Australia (one for adults and one for children). We used an Ultraviolet Aerodynamic Particle Sizer (UVAPS) to identify fluorescent particle sources, as well as their contribution to total particle concentrations. We found that the average concentrations of both fluorescent and non-fluorescent particles were higher in the adults' hospital (0.06×10⁶ and 1.20×10⁶  particles/m³ , respectively) than in the children's hospital (0.03×10⁶ and 0.33×10⁶  particles/m³ , respectively) (P<.01). However, the proportion of fluorescent particles was higher in the children's hospital. Based on the concentration results and using activity diaries, we were able to identify sources of particle production within the two hospitals. We demonstrated that particles can be easily generated by a variety of everyday activities, which are potential sources of exposure to pathogens. Future studies to further investigate their role in nosocomial infection are warranted.

The Oral Microbiome in Health and Its Implication in Oral and Systemic Diseases

The oral microbiome can alter the balance between health and disease, locally and systemically. Within the oral cavity, bacteria, archaea, fungi, protozoa, and viruses may all be found, each having a particular role, but strongly interacting with each other and with the host, in sickness or in health. A description on how colonization occurs and how the oral microbiome dynamically evolves throughout the host's life is given. In this chapter the authors also address oral and nonoral conditions in which oral microorganisms may play a role in the etiology and progression, presenting the up-to-date knowledge on oral dysbiosis as well as the known underlying pathophysiologic mechanisms involving oral microorganisms in each condition. In oral pathology, oral microorganisms are associated with several diseases, namely dental caries, periodontal diseases, endodontic infections, and also oral cancer. In systemic diseases, nonoral infections, adverse pregnancy outcomes, cardiovascular diseases, and diabetes are among the most prevalent pathologies linked with oral cavity microorganisms. The knowledge on how colonization occurs, how oral microbiome coevolves with the host, and how oral microorganisms interact with each other may be a key factor to understand diseases etiology and progression.

Evaluating Transportation by Comparing Several uses of Rotary Endodontic Files

AIM

To evaluate the frequent use of ProTaper Next (PTN; Dentsply Maillefer, Ballaigues, Switzerland) systems on shaping ability of root canal utilizing Solidworks (2014, Dassault Systemes) software.

MATERIALS AND METHODS

Thirty-six root canals in clear resin blocks (Dentsply-Maillefer) were allocated into six experimental groups (n = 36). Six new sets of PTN instruments (Dentsply Maillefer, Ballaigues, Switzerland) were used six times to shape the resin blocks. A #15 K-file was inserted to the working length (WL), followed by ProGlider (PG) to create a glide path. Sequential use of PTN instrumentation in a crown-down technique was used to reach size (30/07) apically. Macroscopic photos of the blocks were taken before and after instrumentation, layered by Paint Shop Pro 9 from JascSoftware, and then canal transportation was measured using Solidwork 2014. The data were analyzed by SPSS software version 22. Multivariate statistical analysis general linear model (GLM) was also applied. Bonferroni correction test was used in multiple comparisons and the statistical significance was set to 0.05.

RESULTS

There was no difference in canal transportation resulted from utilizing PTN files after six multiple uses; in addition, the PTN files showed ability to maintain the original canal anatomy, especially in the apical level, where lowest total mean value of canal center displacement was seen (3 mm level) (0.019 ± 0.017).

CONCLUSION

ProTaper Next files can be used to prepare single and multiple canals in a single furcated tooth.

CLINICAL SIGNIFICANCE

ProTaper Next nickel-titanium (NiTi) file system is a safe instrument that respects the canal shape, allows practitioners to treat difficult cases with good results, and low risk of separation.

Morphological, compositional and ultrastructural changes in the Scrobicularia plana shell in response to environmental mercury--an indelible fingerprint of metal exposure?

The study aimed to assess morphological, structural and compositional alterations in Scrobicularia plana nacre environmentally exposed to mercury in order to seek out the possibility of the assessed alterations as a monitoring tool to handle complexity and interactions of metals in the environment involving a non-invasive methodology. Bivalves were collected from a mercury contaminated site (Laranjo basin - Ria de Aveiro, Portugal) and a reference site in the same aquatic system. The combination of scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDS) technique depicted a sheet like morphology of bivalve nacre collected from the reference site. Moreover, EDS plot exhibited the presence of potassium, oxygen, calcium, and carbon elements. Shells collected from the contaminated area depicted lamellar patches like structures with particle like morphology composition. SEM images corresponding to the elemental analysis by EDS plot clearly denoted the presence of mercury. SEM images from the other locations of the contaminated shells depicted large surface area, a broken or ruptured symmetry of organic matrix as well as crack-like gaps. The influence of environmental mercury affecting the surface morphology of S. plana nacre showed dimple like morphology (as proved by transmission electron microscopy, TEM). The possible explanation may be the replacement of calcium elements with other elements or alloys from the nacre composite collected from contaminated region. Therefore, the nacre fingerprint may be useful as innovative knowledge and applicable tool aiming at risk reduction from noxious mercury present in the environment. Overall results suggested the use of shell as an indelible fingerprint of metal exposure.

Toxicity of chromated copper arsenate: a study in mice

Chromated copper arsenate (CCA) was widespread used as a chemical wood preservative with application in the construction of playground equipment, fences, jetties, and naval. Environmental protection agency (EPA) had limited the use of CCA-treated wood on 2002, due to probable implications on both human and environmental health. Although this fact, several industries pursue the use of this product within their manufactories. In addition, the durability of this wood for 60 years, makes these treated products an hazard to the public health. In the present work, studies were explored exposing mice to CCA, during 14, 24, 48, and 96 h for the assessment of acute toxicity of CCA. Kidney and liver were removed, prepared for histology and for metalloid, and copper content evaluation by high resolution inductively coupled plasma mass spectroscopy. The histological results evidenced apparently normal structures for control animals and group exposed to As2O5. On the contrary, the renal sections of the animals treated with CCA revealed epithelium cells desquamation, hyaline, and granular casts in renal tubules lumen. Furthermore, high levels of arsenic were detected in the kidney of animals treated with CCA over 14 and 48 h, being significantly greater than controls. Although this approach underlines the potential hazard of CCA on some vital organs, further testing may be required to establish the impacts on other functions.

Simultaneous effects of nicotine, acrolein, and acetaldehyde on osteogenic-induced bone marrow cells cultured on plasma-sprayed titanium implants

PURPOSE

To evaluate the potential interaction/contribution of inductive and deleterious effects of tobacco compounds on human osteoblastic cells cultured on plasma-sprayed titanium implants exposed to combinations of nicotine, acrolein, and acetaldehyde. Cell response was assessed as proliferation and function.

MATERIALS AND METHODS

Titanium implants, seeded with human bone marrow-derived cells (first subculture), were cultured in osteogenic-inducing conditions for 28 days in the absence (control) and in the presence of tobacco compounds to assess (1) the dose-dependent profile of acrolein (0.01 to 0.12 mmol/L) and acetaldehyde (0.1 to 6 mmol/L) and (2) the effect of the simultaneous exposure to combinations of nicotine, acrolein, and acetaldehyde. In later experiments, seeded implants were exposed to two different concentrations of nicotine (1.2 mmol/L, known to have inductive effects on cell behavior, and 2.4 mmol/L, reported to elicit deleterious effects on cell behavior) with acrolein, acetaldehyde, or both, at a concentration that inhibits 50% (IC50).

RESULTS

Acrolein and acetaldehyde caused dose-dependent inhibitory effects at levels similar to and greater than 0.03 and 0.1 mmol/L, respectively; IC50 regarding cell viability/proliferation and alkaline phosphatase was 0.06 mmol/L for acrolein and 0.3 mmol/L for acetaldehyde. Matrix mineralization was prevented at levels higher than 0.03 mmol/L acrolein and 0.1 mmol/L acetaldehyde. Exposure to a combination of nicotine 1.2 mmol/L with acrolein (0.06 mmol/L), acetaldehyde (0.3 mmol/L), or both resulted in a cell behavior intermediate to that observed in nicotine-treated cultures (induced cell response) and aldehyde-treated cultures (deleterious cell response). On the other hand, exposure to nicotine 2.4 mmol/L with acrolein (0.06 mmol/L), acetaldehyde (0.3 mmol/L), or both caused cumulative cytotoxic responses.

CONCLUSION

Results suggest that interactions of tobacco compounds on osteoblasts might contribute to the overall effects of tobacco use on implant osseointegration and long-time survival.

Effect of nicotine in matrix mineralization by human bone marrow and Saos-2 cells cultured on the surface of plasma-sprayed titanium implants

Smoking has an established negative impact in the clinical outcome of dental implants. This work analyses the response of human osteoblastic cells to nicotine, at the surface of plasma-sprayed commercial titanium implants. Human bone marrow (HBM) and Saos-2 cells, seeded on the surface of titanium implants and cultured in experimental conditions favoring osteoblastic differentiation, were exposed continuously to nicotine (0.0001 to 0.5 mg mL(-1)) and characterized for cell proliferation and function. Exposure of HBM cells resulted in increased cell proliferation, higher alkaline phosphatase (ALP) activity, and earlier onset of matrix mineralization at levels up to 0.2 mg mL(-1), an initial inhibitory effect in cell growth and functional activity followed by a recovery in the presence of 0.3 mg mL(-1) and a dose-dependent deleterious effect at higher levels. By contrast, exposure to nicotine did not affect cell proliferation of Saos-2 cells at levels up to 0.2 mg mL(-1), and caused only a small positive effect in ALP activity in the presence of 0.05 and 0.1 mg mL(-1); however, matrix mineralization by Saos-2 cells also occurred earlier in the cultures exposed to levels of nicotine up to 0.1 mg mL(-1). Higher concentrations caused dose-dependent inhibitory effects. Considering the high diffusion potential of nicotine, results suggest a local role of nicotine in modulating bone formation events at the implant surface.

Histopathological changes and erythrocytic nuclear abnormalities in Iberian green frogs (Rana perezi Seoane) from a uranium mine pond

In spite of their sensitivity to anthropogenic stressors, adults of Rana perezi Seoane were found inhabiting effluent ponds from a uranium mine. Due to the presence of such organisms in this environment, it becomes of paramount importance to assess the damages induced by local contamination on these aquatic vertebrates, in order to integrate this information on a site-specific risk assessment that is being carried out in the area. To attain this purpose an ethically and statistically acceptable number of green frogs were captured in the mine pond (M) and in a pristine river (VR), a few kilometres from the mine. Bioaccumulation of metals and histopathological alterations were evaluated in the liver, kidneys, spleen, lungs and testes of the animals. Simultaneously, blood samples were collected for the evaluation of genotoxic damage on erythrocytes. Animals captured in the M pond showed significantly increased levels of Be, Al, Mn, Fe and U in the liver, as well as Pb and U in the kidney. The liver was the main target organ for the bioaccumulation of Be, Al, Fe and U. However, renal histopathologies were more severe than those of liver. The main tissue alterations recorded in animals from the mine were: a slight increase in melanomacrophagic centers (MMC) in liver, lung and kidneys; dilatation of the renal tubules lumen associated with tubular necrosis. A significantly higher number of erythrocytic abnormalities (lobed, notched and kidney shaped nuclei and micronuclei) were recorded in frogs from M than in frogs from VR, along with a significantly lower frequency of immature erythrocytes. Both observations suggested that the removal of abnormal blood cells might be compromised.

Antigenotoxic effects of quercetin, rutin and ursolic acid on HepG2 cells: evaluation by the comet assay

In the present study, the chemoprotective effects of quercetin, rutin and ursolic acid on tert-butyl hydroperoxide (t-BHP)-induced DNA damage in a human hepatoma cell line (HepG2) were investigated by the comet assay. To determine whether protection was due to direct chemical interactions alone or to cellular-mediated responses three different types of treatments were used: simultaneous incubation of cells with individual test compounds and the toxicant; pre-treatment with test compound before addition of the toxicant followed or not by a recovery period. The expression of Hsp70 was quantified by Western blotting to test the involvement of heat shock proteins in the cellular responses to the test compounds. In addition, effects on proliferation were evaluated by the MTT assay. The results show that quercetin and ursolic acid prevented DNA damage and had antiproliferative properties in HepG2 cells suggesting an anticarcinogenic potential for these compounds. The protective effects of quercetin against t-BHP-induced DNA damage seem to be due to both direct effects on t-BHP toxicity and to cellularly mediated indirect effects which reflect the potentiation of the cellular antioxidant defenses. Ursolic acid seems to exert effects only through cellularly mediated mechanisms since it was not protective in simultaneous incubation. Quercetin and ursolic acid also showed to increase the rate of DNA repair. Rutin did not have effects at any level. These results, obtained with liver cells, emphasize and confirm the chemopreventive potential of quercetin and ursolic acid, which may help explain the lower cancer incidence in human population with high dietary intakes of fruits and vegetables. These results also demonstrate that Hsp70 is not involved in the observed effects in HepG2.

Lunularia cruciata, a potential in vitro host for Glomus proliferum and G. intraradices

A study was conducted to define culture conditions for in vitro growth arbuscular mycorrhizal fungi (AMF) with liverworts as hosts. Lunularia cruciata (L.) Dumortier ex. Lindberg developed in vitro monoxenic mycothalli with both Glomus proliferum Dalpé & Declerck (MUCL 41827) and Glomus intraradices Schenck & Smith (MUCL 43204). AMF inoculated plants were co-cultured in plastic Petri dishes with semi-solidified medium supplemented with sucrose and grown under filtered light. Mycothalli of L. cruciata produced external hyphae and spores in quantities equivalent to those obtained with Ri T-DNA transformed root systems.

Acute effects of 3,4-dichloroaniline on biomarkers and spleen histology of the common goby Pomatoschistus microps

The aromatic amine 3,4-dichloroaniline (DCA) is a model environmental contaminant, precursor for synthesis and degradation product of several herbicides, which is commonly found in European estuarine ecosystems. In this work, the possibility of using biochemical and histological markers to assess sub-lethal effects of DCA in natural populations of Pomatoschistus microps juveniles was investigated. Alterations on the activities of the enzymes acetylcholinesterase (AChE), lactate dehydrogenase (LDH) and glutathione S-transferase (GST) and histological alterations on spleen were investigated after 96 h of exposure to sublethal concentrations of DCA (0.50-1.49 mg/l). At the concentrations tested, DCA had no effect on AChE activity. LDH and GST activities were significant altered in treated animals when compared to control groups. As already described for mammals, DCA induced splenic histological alterations in P. microps, including expansion of red pulp and deposition of hemosiderin granules in a concentration-dependent manner. This suggests that DCA is a xenobiotic of concern in estuaries receiving agricultural effluents.

Tissues and hair residues and histopathology in wild rats (Rattus rattus L.) and Algerian mice (Mus spretus Lataste) from an abandoned mine area (Southeast Portugal)

Data gathered in this study suggested the exposure of rats and Algerian mice, living in an abandoned mining area, to a mixture of heavy metals. Although similar histopathological features were recorded in the liver and spleen of both species, the Algerian mouse has proved to be the strongest bioaccumulator species. Hair was considered to be a good biological material to monitor environmental contamination of Cr in rats. Significant positive associations were found between the levels of this element in hair/kidney (r=0.826, n=9, p<0.01) and hair/liver (r=0.697, n=9, p=0.037). Although no association was found between the levels of As recorded in the hair and in the organs, the levels of this element recorded in the hair, of both species, were significantly higher in animals captured in the mining area, which met the data from the organs analysed. Nevertheless, more studies will be needed to reduce uncertainty about cause-effect relationships.

S100B and NSE serum concentrations in Machado Joseph disease

BACKGROUND

NSE and S100B are considered as neuronal and glial peripheral markers of central nervous system pathologies, respectively. We evaluated the potential use of S100B and NSE serum concentrations as peripheral markers of symptomatic patients with Machado Joseph disease (MJD).

METHODS

We measured S100B and NSE peripheral concentrations of 22 MJD patients and compared with healthy subjects concentrations. The correlations of both markers with CAG repeat size, age of onset, disease duration, and the scores of the Extended Disability Status Scale of Kurtzke, Unified Parkinson's Disease Rating Scale, and the Montgomery-Asberg depression rating scale were also assessed.

RESULTS

S100B serum concentrations between control and MJD subjects were not statistically different, whereas NSE serum concentrations were higher in MJD patients than in control subjects (p=0.00001). S100B presented a moderate correlation with disease duration and depression score, whereas NSE presented a moderate correlation with depression score and a good negative correlation with EDSS score.

CONCLUSIONS

Symptomatic MJD patients present increased concentrations of NSE and normal concentrations of S100B in blood.

Searching for modulating effects of SCA2, SCA6 and DRPLA CAG tracts on the Machado-Joseph disease (SCA3) phenotype

CONTEXT

Machado-Joseph disease (MJD/SCA3) is an autosomal dominant cerebellar ataxia of adult onset. The variability in age at onset and the complex and heterogeneous neurologic findings indicate that MJD, caused by a major gene, is modulated by modifier factors.

OBJECTIVE

To study if the polymorphic CAG repeats at other loci (namely, SCA2, SCA6 and DRPLA) thus acted as modifier factors of this disease.

DESIGN

Case-control.

SETTING

Ambulatory care in a referral center.

PATIENTS

A convenience sample of 39 unrelated, Brazilian patients with MJD.

MAIN OUTCOME MEASURES

age of onset, anticipation, clinical subtypes and neurological findings.

RESULTS

Fasciculations were associated with CAG repeat length of the long SCA2 allele (Mann-Whitney U-test, P < 0.03, after Bonferroni procedure). Other measures (age of onset, anticipation, clinical types and other neurological signs) were not associated with CAG repeat length of SCA2, SCA6 and DRPLA genes.

CONCLUSIONS

The present results show that the CAG tract of SCA2 gene interferes with MJD phenotype. Further studies, with patients of other origins and with typing of other (CAG)n loci, are necessary.

Use of fluoxetine for treatment of Machado-Joseph disease: an open-label study

CONTEXT

Machado-Joseph Disease (MJD/SCA3) is an autosomal dominant spinocerebellar degeneration that evolves to disability and death. Experimental data have shown that serotonin is an important cerebellar neurotransmitter and that impairment of the serotoninergic cerebellar system can induce cerebellar ataxia.

OBJECTIVES

To evaluate the efficacy of fluoxetine, a serotonin reuptake inhibitor, in treating neurologic dysfunction in patients with MJD.

PATIENTS AND METHODS

Thirteen MJD patients were treated with fluoxetine (20 mg/day) and were followed-up for 6 weeks. Outcome measures included functional capacity, standardized neurologic and cognitive ratings. The Montgomery-Asberg depression rating scale was used to control depressive symptoms.

RESULTS

There was no significant improvement in motor abilities after 6 weeks of treatment.

CONCLUSIONS

These results suggest that fluoxetine has no benefit in motor function of patients with MJD/SCA3.

Cr(V) involvement in the toxicity pathway of testicular damage

AIM

The functional integrity of the blood-testis barrier (BTB) in male mice exposed to Cr(V) was studied in order to clarify the mechanism underlying testicular injury.

METHODS

Adult male mice were subcutaneously injected repeated doses of 8.02 micromol (0.5 ml) of Cr/mouse.day for 5 days. Animals receiving a similar volume of bis(hydroxyethyl)-aminotris(hydroxymethyl)methane buffer (BT) were used as controls. The animals were sacrificed on day 6 and small fragments of seminiferous tubules, approximately 8-10 mm length, were incised and sutured at both ends. They were exposed in vitro to horseradish peroxidase-containing culture medium for 10 minutes. Tissues were then fixed and processed for ultrastructural studies.

RESULTS

Controls and Cr(V)-treated group resulted in the uptake of the tracer by Sertoli cells. However, the major finding consisted in the permeability of the BTB only in the Cr(V)-group, as evidenced by the presence of the tracer within the junctions between the neighbouring Sertoli cells.

CONCLUSION

The BTB is disrupted in mice submitted to Cr(V). The permeability of the BTB is a crucial feature to be investigated for the understanding of lesions within the seminiferous tubule.

Machado-Joseph disease in South Brazil: clinical and molecular characterization of kindreds

OBJECTIVE

To examine the clinical, genetic, and molecular characteristics of a group of MJD patients recently identified in the southernmost state of Brazil, and compare these data with studies from the literature.

METHODS

Some 62 individuals from 35 families, mostly of Azorean ancestry, had their clinical data and their MJD1 expanded regions examined.

RESULTS

The present patients had an earlier age of onset, on average, than Portuguese-Azorean cases. Their survival, proportion of types, average anticipation, proportion of affected versus non-affected siblings, neurological signs and molecular findings are similar to those observed in patients previously described. Type 1 patients with male transmission showed worse anticipations than type 1 patients with female transmission. Patients with type 1 had also larger CAG expansions than other patients.

CONCLUSIONS

The Brazilian origin seemed to affect the age of onset. We also noted that there were no differences other than the neurological between types 2 or 3, since both are similar in age of onset, disease duration and length of CAG repeats. We addressed the question of maintaining or not subtypes 2 and 3 separated, among patients with genetic and geographical backgrounds like the presented patients here.

A survey of spinocerebellar ataxia in South Brazil - 66 new cases with Machado-Joseph disease, SCA7, SCA8, or unidentified disease-causing mutations

BACKGROUND

The autosomal dominant spinocerebellar ataxias (SCAs) are a clinical and genetically heterogeneous group of debilitating, neurodegenerative diseases, related to fourteen different loci - SCAs 1, 2, 4, 5, 6, 7, 8, 10, 11,12,13 and 14, Machado-Joseph disease (MJD/SCA 3), and DRPLA.

OBJECTIVES

(1) To verify the frequency of SCA1, SCA2, MJD, DRPLA, SCA6, SCA7 and SCA8 in a series of new SCA patients from South Brazil and (2) to compare their molecular and clinical characteristics with other patients previously described.

METHODS

Sixty-six cases were included in the present study: 52 were familial and 14 sporadic. Molecular analysis of the trinucleotide repeat loci were performed according to methods in the literature.

RESULTS

92% of families with autosomal dominant inheritance segregated the MJD1 mutation,2% of families segregated the SCA7 mutation and 6% remained undiagnosed. Among 14 isolated cases, one showed the SCA8 mutation. Clinical and molecular findings were similar to those already described in the literature, but revealed (1) one SCA7 patient with eyelid retraction, a sign usually related to MJD; and (2) one sporadic case of SCA8.

CONCLUSIONS

The proportion of MJD cases was very high, probably reflecting an Azorean founder effect. The estimated frequency of affected individuals with MJD, in our region, was 1.8 / 100,000, and of SCAs other than MJD, 0.2/100,000.

Neurologic findings in Machado-Joseph disease: relation with disease duration, subtypes, and (CAG)n

CONTEXT

Machado-Joseph disease (MJD), an autosomal dominant spinocerebellar degeneration caused by an expanded CAG repeat on chromosome 14q32.1, is a heterogeneous disorder for clinical manifestations. The reasons for the wide range of neurologic findings in this disease are poorly understood.

OBJECTIVE

To explain part of this heterogeneity through the association of the neurologic findings with sex, disease duration, age of onset, clinical type, and size of CAG repeat expansion.

DESIGN

A case-control study.

SETTING

Ambulatory care.

PATIENTS

A consecutive sample of 62 patients with MJD.

MAIN OUTCOME MEASURE

Neurologic signs.

RESULTS

A direct relationship was found between the disease duration and severity of gait and limb ataxia, dysarthria, dysphagia, fasciculations, pyramidal syndrome, and ophthalmoplegia (P<.02). The most severe forms of nuclear ophthalmoplegia were associated with type 1 MJD, whereas those of supranuclear ophthalmoplegia were associated with type 3 MJD (P<.001). It was also found that higher mean (CAG)(n) lengths were associated with worse degrees of the pyramidal syndrome and dystonia (P<.001). The presence and severity of nystagmus, eyelid retraction, rigidity and/or bradykinesia, and optic atrophy were not clearly associated with any of the predictive variables under study.

CONCLUSIONS

Disease duration can explain part of the heterogeneity of ataxia, dysarthria, dysphagia, fasciculations, pyramidal syndrome, and ophthalmoplegia, in MJD. Type 1 MJD was positively associated with nuclear ophthalmoplegia; type 3 MJD was positively associated with supranuclear ophthalmoplegia. Higher mean CAG lengths were found to correlate with the pyramidal syndrome and dystonia. Nystagmus, eyelid retraction, rigidity and/or bradykinesia, and optic atrophy were hardly attributable to any known reason or variable.

Penetrating keratoplasty in iridocorneal endothelial syndrome

PURPOSE

To evaluate the clinical outcome of penetrating keratoplasty (PK) in iridocorneal endothelial (ICE) syndrome.

METHODS

Clinical charts of patients who underwent penetrating keratoplasty for ICE syndrome between 1985 and 1999 were reviewed retrospectively. Glaucoma control, best corrected visual acuity pre- and post-PK, graft clarity, graft rejection episodes, improvement in pain, and additional procedures were analyzed.

RESULTS

Fourteen cases were reviewed with an average follow-up of 58 months after PK. Initial grafts failed in seven patients (50%), in six cases because of rejection, and one owing to endothelial failure without signs of rejection. Repeat PKs were performed in six patients. At final follow-up, 12 grafts were clear. Glaucoma was controlled pre- and post-PK (average intraocular pressure, 16 mmHg for both eyes). Pre-PK, eight patients were using glaucoma medicines and nine had had glaucoma surgery. At the end of the follow-up, seven patients were using glaucoma medicines; six patients required glaucoma surgery after their initial PK. At the final follow-up visit, visual acuity in three patients (21%) was 20/40 or better, it ranged from 20/50 to 20/100 in four patients (29%) and 20/200 to 20/400 in five patients (36%), and in two patients with failed grafts (14%) it was counting fingers or worse.

CONCLUSION

Clear grafts were achieved in 12 cases, although six patients (43%) underwent repeat PKs. All patients had glaucoma, which was controlled before and after PK by medical treatment and surgical procedures. Favorable outcomes can be achieved in patients with ICE syndrome but may require multiple corneal and glaucoma procedures.

Staphylococci from dental personnel

Thirty dental students and five professors were cultured in nares, throat, and hands for the presence of staphylococci. Twenty-four students and two professors were colonized with staphylococci that were classified as S. aureus. Twelve students and one professor were colonized with staphylococci that produced enterotoxin. Care needs to be taken to avoid contaminating patients during dental examination, particularly during any type of surgery.

[Being a mother affected with AIDS: reliving the original sin]

This study aimed to understand the meaning of being with AIDS among HIV/AIDS mothers. It looks for to identify the emotions and the way of cope with the situation as a mother has a healthy son. This study was conducted based on the Social Representations Theory. The findings showed "to be mother" and "to have AIDS" represented as a process that does not finish in the disease itself. Also it was found that there is a polarize link between the good and the evil. Indeed, this study brought the sexuality likewise the polarized link, being AIDS linked to evil aspect. These women from this study had perceived themselves as guilty of something, as a result, they deserved the punishment that the AIDS imposed on them.

[Integration of health into the school curriculum in Botucatu, São Paulo]

This study focuses on the drafting and development of a public health program aimed at strategies to integrate health activities and the school curriculum. The program is based on three main lines of activity: full health care for schoolchildren, with special emphasis on the public school system; training of personnel in the fields of health and education by means of internships allowing participants to experience, work, and reflect critically on the activities with an interdisciplinary team; and work with teachers from the public elementary school system to implement and develop innovative measures in the fields of health and education to respond to the demand by schools and the community.

Histological effects of iron accumulation on mice liver and spleen after administration of a metallic solution

Special attention has been focused on the toxicity of some metallic species released from implanted materials, which accumulate in vital organs over long periods of time. A set of experiments with mice was designed to investigate the individual effects caused by iron in the liver and spleen. Histological features of these organs were evaluated and slight morphological changes were observed during the treatment time suggesting a negative correlation with the duration of the iron treatment. In addition, to associate the histological changes in the organs with iron accumulation an electrochemical method, adsorptive stripping voltammetry, was chosen to quantify the iron levels in these mentioned organs. The accuracy of the proposed method was checked by atomic absorption spectrometry. Both organs showed elevated concentrations of iron, nearly twofold, 7 days after iron administration compared to control organs.

[Contamination of public squares of Campo Grande, Mato Grosso do Sul, Brazil, with eggs of Toxocara and Ancylostoma in dog feces]

From February to October 1998, the contamination of public squares of Campo Grande, MS, Brazil, by eggs of Toxocara and Ancylostoma was evaluated in dog fecal samples. Out of the 74 public parks examined, 42 (56.8%) were found to be contaminated with Ancylostoma eggs, 8 (10.8%) with Toxocara eggs and 7 (9.5%) with both.

Arylsulfatase A pseudodeficiency in healthy Brazilian individuals

Molecular alterations associated with arylsulfatase A pseudodeficiency (ASA-PD) were characterized by PCR and restriction endonuclease analysis in a sample of healthy individuals from Brazil. ASA activity was also assayed in all subjects. Two individuals homozygous for the N350S and 1524+95A<--G mutations were detected, corresponding to a frequency of 1.17% (4 of 324 alleles). The individual frequency of the N350S mutation was 20.7% (71 of 342 alleles) and 7.9% (27 of 342 alleles) for the 1524+95A<--G mutation. The frequency of the ASA-PD allele in our population was estimated to be 7.9%. This is the first report of ASA-PD allele frequency in a South American population. In addition, the methods used are effective and suitable for application in countries with limited resources. All patients with low ASA activity should be screened for ASA-PD as part of the diagnostic protocol for metachromatic leukodystrophy.

Evaluation of nickel toxicity on liver, spleen, and kidney of mice after administration of high-dose metal ion

The toxic effects caused by nickel (Ni) per si were explored by performing in vivo studies on mice following subcutaneous administration of a metallic solution of nickel at 1, 2, 3, and 4 weeks to evaluate the side effects of this metal ion when released from stainless steel implants. Other groups were similarly injected with HBSS and used as controls. Accumulation of Ni ions on liver, spleen, and kidney was assessed by an electrochemical method, adsorptive stripping voltammetry (AdSV) using microelectrodes, and atomic absorption spectrometry (AAS). Alterations of those organs induced by Ni ions were studied, showing that several histological changes had been induced. Chemical analysis and histological features indicate that Ni is partially accumulated in the study organs.

Adsorptive stripping measurements of iron accumulation in mice kidney using microelectrodes and histological features

The toxic effects caused by iron in kidney was performed on experimental studies with mice following administration of a metallic solution of this species to simulate the iron corrosion products of a metallic implant. To quantify the total levels of iron present in this organ, an electrochemical method was chosen based on the application of square wave voltammetry using adsorptive collection of iron-catechol on a mercury film microelectrode (MFM). The optimal working conditions to produce a very stable and reproducible iron peak in the digested kidney samples were found to be pH = 7.2 provided by 8.0 mmol/L PIPES buffer, catechol concentration of 3.0 x 10(-4) mol/L, deposition potential -1.80 V and deposition time 20 s. These results were compared with those obtained by atomic absorption spectrometry (AAS) indicating a good performance of the electrochemical method used. The analytical results show an increase of iron concentration with treatment time, which indicates that this metal ion is partially accumulated in the kidney. This accumulation induces with time some morphological alterations as evidenced by the histological analysis.

Fast-atom bombardment tandem mass spectrometry of cyclic nucleotide analogues used as site-selective activators of cyclic nucleotide-dependent protein kinases

The mass spectrometric behaviour of six cyclic nucleotide analogues which activate cyclic AMP-dependent protein kinase was studied by positive-ion fast-atom bombardment (FAB) and collision-induced dissociation (CID) mass-analysed ion kinetic energy (MIKE) spectrometry. The compounds studied were 1,N6-ethenoadenosine-3',5'-cyclic monophosphate, (epsilon-cyclic AMP) and 2'-aza-1,N6-ethenoadenosine-3',5'-cyclic monophosphate, which each activate both isoforms of cyclic AMP-dependent protein kinase and have similar affinity for both the 'fast' and the 'slow' regulatory site of each isoform, N6-phenyl-cyclic AMP, which is selective for the 'fast' regulatory site of each isoform, and 6-chloropurine riboside-3',5'-cyclic monophosphate, 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole-3',5'-cyclic monophosphate and 8-(4-chlorophenylthio)-adenosine-3',5'-cyclic monophosphate, which are each selective for the 'slow' regulatory site and preferentially activate isoform II. The FAB- and CID/MIKE spectra of the analogues are discussed in relation to their use in studies of the regulation of protein kinase activity by quantitative FAB mass spectrometry.

Prevention of nonspecific reactions on reversed passive latex agglutination assay (RPLA) for detecting low amounts of staphylococcal enterotoxins

The SET-RPLA, from Denka Seiken Co. Ltd., Tokio, a commercial reversed passive latex agglutination test kit, has been recommended to establish the enterotoxicity capacity of some staphylococcal strains, implicated in food poisoning outbreaks that produce low levels of enterotoxins (SE). Despite the RPLA specificity, the occurrence of nonspecific reactions when testing low-SE-producing is common. In order to control these nonspecific reactions the addition of purified normal rabbit IgG purified was applied on approximately 350 staphylococcal isolates from human milk and anatomic sites of healthy dental student carriers. The results indicated that addition of 5% (v/v) of purified normal rabbit IgG (0.74 mg/mL) to the culture supernatant fluid is a simple and reliable tool for the controlling of nonspecific reactions in the RPLA assay.

Studies on the permeability of the blood-testis barrier in stainless steel-administered mice

Previous trials performed in our laboratory have demonstrated that stainless steel corrosion products induced morphological changes in mice seminiferous cells. In this study the functional nature of the blood-testis barrier was investigated, in view of the extensive use of this metallic alloy in orthopaedic surgery. The uptake of horseradish peroxidase by the seminiferous tubules was used as a tracer method being exposed in vitro for different periods of time and observed at the ultrastructural level. Both boundary cells as well as Sertoli cells of experimental group absorbed the tracer, as manifested by vesicles and vacuoles filled with the reaction product, evidencing its role within the testis. Germ cells were also able in the uptake of this macromolecule. However, the tracer did not spread into the junctional complexes between neighboring Sertoli cells, at any interval of time used in this study, demonstrating the functional integrity of this barrier.