Research on implants and osseointegration.

Osseointegration was originally defined as a direct structural and functional connection between ordered living bone and the surface of a load-carrying implant. It is now said that an implant is regarded as osseointegrated when there is no progressive relative movement between the implant and the bone with which it is in direct contact. Although the term osseointegration was initially used with reference to titanium metallic implants, the concept is currently applied to all biomaterials that have the ability to osseointegrate.

Similar expression pattern of NHERF1 and EZRIN in papillary but not in solid areas of human serous ovarian carcinomas.

NHERF1 is an adaptor protein expressed in the apical membrane of polarized epithelia, which interacts with the EZRIN-Radixin-Moesin (ERM) family of proteins connecting signaling pathways to the cell cytoskeleton. NHERF1 and EZRIN cooperate in the maintenance of the apical microvilli in polarized epithelial cells. In several types of cancers, NHERF1 and EZRIN are displaced from the apical compartment to the cytoplasm and nuclei of cancer cells.

Efficacy of Core Needle Biopsy Technique for Jawbone Diseases.

Core needle biopsy (CNB) has been proven useful for diagnosing bone lesions, although it is not often used for jawbone lesions. The aim of this study was to evaluate the efficacy of the CNB method in a series of cases of intramaxillary lesions. CNB was performed on 85 patients with intraosseous lesions which were grouped according to radiographic appearance as: radiopaque lesions (RO, n=13), radiolucent lesions (RL, n=39) and mixed lesions with both radiolucent and radiopaque areas (RL-RO, n=33).

Experimental set up for the irradiation of biological samples and nuclear track detectors with UV C.

Aim: In this work we present a methodology to produce an "imprint" of cells cultivated on a polycarbonate detector by exposure of the detector to UV C radiation.

Background: The distribution and concentration of (10)B atoms in tissue samples coming from BNCT (Boron Neutron Capture Therapy) protocols can be determined through the quantification and analysis of the tracks forming its autoradiography image on a nuclear track detector. The location of boron atoms in the cell structure could be known more accurately by the simultaneous observation of the nuclear tracks and the sample image on the detector.

Experimental Studies of Boronophenylalanine ((10)BPA) Biodistribution for the Individual Application of Boron Neutron Capture Therapy (BNCT) for Malignant Melanoma Treatment.

Purpose: Patients with the same histopathologic diagnosis of cutaneous melanoma treated with identical protocols of boron neutron capture therapy (BNCT) have shown different clinical outcomes. The objective of the present studies was to evaluate the biodistribution of boronophenilalanina ((10)BPA) for the potential application of BNCT for the treatment of melanoma on an individual basis.

Methods And Materials: The boronophenilalanine (BPA) uptake was evaluated in 3 human melanoma cell lines: MEL-J, A375, and M8.

Simultaneous Observation of Cells and Nuclear Tracks from the Boron Neutron Capture Reaction by UV-C Sensitization of Polycarbonate.

The distribution of boron in tissue samples coming from boron neutron capture therapy protocols can be determined through the analysis of its autoradiography image on a nuclear track detector. A more precise knowledge of boron atom location on the microscopic scale can be attained by the observation of nuclear tracks superimposed on the sample image on the detector. A method to produce an "imprint" of cells cultivated on a polycarbonate detector was developed, based on the photodegradation properties of UV-C radiation on this material.

In vitro age dependent response of macrophages to micro and nano titanium dioxide particles.

As a result of corrosion, microparticles (MP) and/or nanoparticles (NP) can be released from the metallic implants surface into the bioenvironment. The biological response to these particles depends not only on the physico-chemical properties of the particles but also on host factors, such as age. Macrophages have attracted wide concern in biomedicine.

Osteosarcoma of the jaw: an analysis of a series of 74 cases.

Aims: To analyse a series of cases of osteosarcoma of the jaw.

Methods And Results: The study included 74 cases of osteosarcoma of the jaw. Their clinical, radiographic and histopathological features were analysed, and their frequency with respect to aggressive and malignant pathologies of the jaw was determined.

Impact through time of different sized titanium dioxide particles on biochemical and histopathological parameters.

Due to corrosion, a titanium implant surface can be a potential source for the release of micro (MPs) and nano-sized particles (NPs) into the biological environment. This work sought to evaluate the biokinetics of different sized titanium dioxide particles (TiO2 ) and their potential to cause cell damage. Wistar rats were intraperitoneally injected with 150 nm, 10 nm, or 5nm TiO2 particles.

Subcellular redistribution of NHERF1 in response to dehydroepiandrosterone (DHEA) administration in endometrial glands of Wistar rats.

To understand the regulation of Na(+)/H(+) exchanger regulatory factor (NHERF1) in polycystic ovarian syndrome, we studied the expression of NHERF1 in uterus of Wistar rats injected with (6 mg/kg) of dehydroepiandrosterone (DHEA) for 7 and 20 days. Immunohistochemistry analysis of NHERF1 showed a substantial shift in the intracellular localization of NHERF1 in endometrial glands and areas of luminal epithelium as early as 7 days of DHEA administration. The NHERF1 accumulated in the "Golgi apparatus area" virtually in all the glands in the 7-day protocol, and in the majority of the glands of 20-day protocol.

Exfoliative cytology and titanium dental implants: a pilot study.

Background: Oral exfoliative cytology is a diagnostic method that involves the study of cells exfoliated from the oral mucosa. Ions/particles released from metallic implants can remain in the peri-implant milieu. The aim of the present study is to assess the presence of metal particles in cells exfoliated from peri-implant oral mucosa around titanium dental implants.

Oral mucosa tissue response to titanium cover screws.

Background: Titanium is the most widely used metal in dental implantology. The release of particles from metal structures into the biologic milieu may be the result of electrochemical processes (corrosion) and/or mechanical disruption during insertion, abutment connection, or removal of failing implants. The aim of the present study is to evaluate tissue response of human oral mucosa adjacent to titanium cover screws.

Expression of NHERF1 in colonic tumors induced by 1,2-dimethylhydrazine in rats is independent of plasma ovarian steroids.

In normal embryonic fibroblasts, the Na(+)/H(+) exchanger regulator factor 1 (NHERF1) stabilizes E-cadherin/β-catenin binding and the lack of NHERF1 expression promotes cell transformation thus acting as a tumor suppressor gene. We here tested the hypothesis that NHERF1 could act as a tumor suppressor gene in colon cancer as a mediator of estrogens' protective actions in colon carcinogenesis. We studied the expression and localization of NHERF1 and β-catenin by immunohistochemistry in colonic tumors induced by 1,2 dimethylhidrazine (DMH) in Sprague-Dawley rats.

In vivo comparative biokinetics and biocompatibility of titanium and zirconium microparticles.

Titanium and zirconium are biomaterials that present a layer of titanium dioxide (TiO(2)) or zirconium dioxide (ZrO(2)). As a result of corrosion, microparticles can be released into the bioenvironment, and their effect on tissues is seemingly associated with differences in the physicochemical properties of these metals. The aim of this study was to perform a long-term evaluation of the distribution, destination, and potential risk of TiO(2) and ZrO(2) microparticles that might result from the corrosion process.

First evaluation of the biologic effectiveness factors of boron neutron capture therapy (BNCT) in a human colon carcinoma cell line.

Purpose: DNA lesions produced by boron neutron capture therapy (BNCT) and those produced by gamma radiation in a colon carcinoma cell line were analyzed. We have also derived the relative biologic effectiveness factor (RBE) of the neutron beam of the RA-3- Argentine nuclear reactor, and the compound biologic effectiveness (CBE) values for p-boronophenylalanine ((10)BPA) and for 2,4-bis (α,β-dihydroxyethyl)-deutero-porphyrin IX ((10)BOPP).

Methods And Materials: Exponentially growing human colon carcinoma cells (ARO81-1) were distributed into the following groups: (1) BPA (10 ppm (10)B) + neutrons, (2) BOPP (10 ppm (10)B) + neutrons, (3) neutrons alone, and (4) gamma rays ((60)Co source at 1 Gy/min dose-rate).

Biochemical changes during goiter induction by methylmercaptoimidazol and inhibition by delta-iodolactone in rat.

Background: We have demonstrated that the administration of delta-iodolactone (i.e., 5-iodo-delta lactone) of arachidonic acid (IL-delta), a mediator in thyroid autoregulation, prevents goiter induction by methylmercaptoimidazol (MMI) in rats.

Ploidy study in oral carcinomas: use of improved methodology to assess its clinical prognostic value.

Objective: This study reports a ploidy analysis in oral squamous cell carcinomas (SCC) using methodologic adjustments to improve the accuracy of the measurements and derive numeric indices of aggressiveness of prognostic value.

Study Design: Sixty-seven SCC were assessed by DNA image cytometry in the areas of the histologic sections with most atypia. Five indices of aggressiveness were analyzed in relation to the clinical-pathologic data and evolution of the patients.

The issue of corrosion in dental implants: a review.

Pure titanium or titanium alloys, and to a lesser extent, zirconium, are metals that are often used in direct contact with host tissues. These metallic biomaterials are highly reactive, and on exposure to fluid media or air, quickly develop a layer of titanium dioxide (TiO2) or zirconium dioxide (ZrO2). This layer of dioxide forms a boundary at the interface between the biological medium and the metal structure, determining the degree of biocompatibility and the biological response of the implant.

Expression of ezrin and metastatic tumor antigen in osteosarcomas of the jaw.

Aims And Background: Ezrin is a membrane-cytoskeleton linker protein involved in regulation of the growth and metastatic behavior of cancer cells. Metastatic tumor antigen (MTA) is a potential metastasis-associated protein. The objective of this study was to evaluate the expression of ezrin and MTA and their correlation with clinicopathological features in osteosarcomas of the jaw.

Osteoconductivity of strontium-doped bioactive glass particles: a histomorphometric study in rats.

There is accumulating evidence that strontium (Sr)-containing bioceramics have positive effects on bone tissue repair. The aims of the present study were to evaluate the osteoconductivity of Sr-doped bioactive glass (BG) particles implanted in rat tibia bone marrow, and characterize the neoformed bone tissue by SEM-energy-dispersive X-ray microanalysis. Melt-derived BGs were prepared from a base 45S5 BG.

Ploidy studies of pleomorphic adenomas and minor salivary gland carcinomas of the palate.

Ploidy studies of tumors are a diagnostic and prognostic aid. The aim of the present study was to evaluate the DNA content of palate aggressive pleomorphic adenomas (PA) and adenocarcinomas of the salivary glands. Twelve cases of salivary gland tumors of the palate were selected from the archives of the Oral Pathology Department, Faculty of Dentistry, University of Buenos Aires (1966-2001).

Clinical features and evolution of oral cancer: A study of 274 cases in Buenos Aires, Argentina.

Unlabelled: Oral Squamous Cell Carcinoma has a low survival rate, 34 to 66% five-year survival after initial diagnosis, due to late diagnosis.

Objectives: The aim of the present study was to examine the clinical features and evolution of oral cancer in the University of Buenos Aires.

Study Design: 274 patients with primary oral carcinoma, over the 1992-2000 period were included in the study.

Biological performance of boron-modified bioactive glass particles implanted in rat tibia bone marrow.

The aim of the present study was to characterize the neoformed bone tissue around boron-modified bioactive glass particles implanted in rat tibia bone marrow by histologic, histomorphometric and microchemical evaluation. Melt-derived glasses were prepared from a base 45S5 bioactive glass of nominal composition (45% SiO(2), 24.5% CaO, 24.