Tribological behaviour of Ti or Ti alloy vs. zirconia in presence of artificial saliva

Abutment is the transmucosal component in a dental implant system and its eventual appearance has a major impact on aesthetics: use of zirconia abutments can be greatly advantageous in avoiding this problem. Both in the case of one and two-piece zirconia abutments, a critical issue is severe wear between the zirconia and titanium components. High friction at this interface can induce loosening of the abutment connection, production of titanium wear debris, and finally, peri-implant gingivitis, gingival discoloration, or marginal bone adsorption can occur. As in vivo wear measurements are highly complex and time-consuming, wear analysis is usually performed in simulators in the presence of artificial saliva. Different commercial products and recipes for artificial saliva are available and the effects of the different mixtures on the tribological behaviour is not widely explored. The specific purpose of this research was to compare two types of artificial saliva as a lubricant in titanium-zirconia contact by using the ball on disc test as a standard tribological test for materials characterisation. Moreover, a new methodology is suggested by using electrokinetic zeta potential titration and contact angle measurements to investigate the chemical stability at the titanium-lubricant interface. This investigation is of relevance both in the case of using zirconia abutments and artificial saliva against chronic dry mouth. Results suggest that an artificial saliva containing organic corrosion inhibitors is able to be firmly mechanically and chemically adsorb on the surface of the Ti c.p. or Ti6Al4V alloy and form a protective film with high wettability. This type of artificial saliva can significantly reduce the friction coefficient and wear of both the titanium and zirconia surfaces. The use of this type of artificial saliva in standard wear tests has to be carefully considered because the wear resistance of the materials can be overestimated while it can be useful in some specific clinical applications. When saliva is free from organic corrosion inhibitors, wear occurs with a galling mechanism. The occurrence of a super-hydrophilic saliva film that is not firmly adsorbed on the surface is not efficient in order to reduce wear. The results give both suggestions about the experimental conditions for lab testing and in vivo performance of components of dental implants when artificial saliva is used

Biología reproductiva de escorpiones: ¿De dónde venimos, cómo estamos y qué nos espera?

En escorpiones, los estudios enfocados en sus patrones y mecanismos de reproducción han sido relativamente frecuentes en ciertas épocas, en tanto muy escasos en otras. En los últimos años, se aprecia un cierto incremento en investigaciones centradas en aspectos puntuales de la selección sexual.Fil: Peretti, Alfredo V. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Diversidad y Ecología Animal; Argentina.Fil: Peretti, Alfredo V. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales Laboratorio de Biología reproductiva y Evolución; Argentina.Zoología, Ornitología, Entomología, Etologí

Virus-like particle vaccines against BK and JC polyomaviruses

Nearly all healthy adults are asymptomatically infected with human polyomaviruses. In immunosuppressed individuals, the infection can reactivate and cause disease. BK polyomavirus (BKV) frequently damages transplanted kidneys and causes severe bladder disease in bone marrow transplant patients. JC polyomavirus (JCV) causes a lethal brain disease, PML, in individuals on various immunosuppressive therapies. PML also affects immunodeficient individuals, including AIDS patients. The outer capsid proteins of polyomaviruses are structurally similar to the capsids of human papillomaviruses (HPVs). Building on the success of the NCI’s HPV virus-like particle (VLP) vaccine technologies, we have developed VLP vaccines targeting BKV and JCV. Preclinical testing in a monkey model indicates that the BKV and JCV VLP vaccines share the HPV vaccines’ exceptionally potent immunogenicity. Given our knowledge of the role that antibodies play in ameliorating polyomavirus pathologies, the new VLP vaccines are likely to protect at-risk patients against the development of BKV-induced urinary tract disease and JCV-induced brain disease. Each year, roughly 30,000 Americans join wait-lists for kidney transplantation. Additionally, roughly 300,000 Americans per year are diagnosed with diseases that might be treated with bone marrow transplantation. Emerging evidence indicates that antibody-producing plasma cells elicited by the BKV vaccine will persist after bone marrow transplantation and the vaccine should thus provide protection against post-transplant hemorrhagic cystitis. The highly effective multiple sclerosis therapy Tysabri (natalizumab) is associated with up to 2% risk of PML side effects. Rituxan (rituximab), which is used for treatment of rheumatoid arthritis and certain types of lymphoma, carries a black box warning for PML and a dozen additional immunosuppressive therapies are also known or suspected to have PML side effects. The JCV vaccine should be a useful preventive adjunct for these popular immunotherapies. Since there are currently no effective treatments for BKV or JCV diseases, the candidate vaccines seem likely to qualify for FDA’s Accelerated Approval Program. The NCI is currently seeking industry partners

Native cattle breeds of Southern Italy: karyological profile

Italian typical products of animal origin are strictly linked to native breeds. Their protection requires control of their reproductive and productive abilities. Hence the need for karyological studies to identify subjects with chromosome abnormalities linked to hypofertility or sterility. We report the results of karyological analyses carried out from January 2008 to December 2008 on 145 cattle of native breeds (Agerolese, Cinisara, Modicana and Podolica) reared in Southern Italy so as to evaluate and characterize the presence of chromosome abnormalities in subjects with normal phenotypes. Besides the 128 karyologically normal subjects (2n=60, XY and 2n=60, XX), 17 were carriers of rob (1;29) and one male was a carrier of cellular chimerism 2n=60, XX/XY. According to our data there is a high frequency of rob (1;29) in Cinisara and Podolica breeds while in Agerolese there was only one case of rob (1;29) and none in Modicana

Chromosome analyses in dairy cows exposed to dioxins and dioxin-like PCBs using the SCE test

Peripheral blood cultures were performed to study the sister chromatid exchanges (SCE) in samples from 15 cows (Valdostana x Piedmontese crossbreds) showing average milk values of dioxins+furans+PCBs higher (18.56 pg/g of fat as WHO-TEQ) than those permitted (6.0 pg/g of dioxins+furans+PCBs as WHO-TEQ) and the results were compared with samples from 16 Valdostana dairy cows (1.75 pg/g of fat as WHO-TEQ) used as control. Significant (P<0.01) higher mean number of SCE/cell (7.10±2.8) were found in cows showing higher levels of dioxins and PCB compared to those achieved in the controls (SCE/cell=5.24±2.51)

An improved characterization of horse (Equus caballus, 2n=64) chromosomes by using replicating G and R banding patterns

Abstract Peripheral blood lymphocytes were cultured and treated for early- and late-BrdU incorporation to perform replicating G- and R-banding patterns, respectively. Slides were treated for GBG-, RBA- and RBG-banding techniques. Improved banded karyotypes at early- (350 bands) and pro-metaphase (500 bands) stage were performed and GBG- and RBA-banded prometaphase karyotypes were presented for the first time on this species. All chromosomes, including the small acrocentrics, show clear and distinguishable G- and R-banding patterns. Chromosome identification followed the latest chromosome standard nomenclature (ISCNH 1997). This study is also our contribution to further standard karyotype attempts at the prometaphase stage

An unusual case of testicular disorder in sex development of arabian mare (64,xx sry-negative)

A 3-year-old Arabian mare underwent medical examinations due to the presence of abnormalities of the reproductive apparatus and stallion behavior (nervous temperament, aggressiveness, masculine attitude). During the clinical visit, an anovulvar distance shorter than normal was observed; moreover, vulvar lips were dorsally fused except for the lower neckline, showing a blind ending from which a penis-like structure protruded. The ultrasound examination revealed the presence of a cervix and corpus of a uterus, hypoplastic uterine horns, and small gonads with an echogenicity similar to a testis. Blood testosterone levels ranged from 0.4 to 0.6 ng/mL. Cytogenetic analysis showed a normal female karyotype (2n = 64,XX), while PCR amplification of SRY and ZFY genes revealed the absence of a Y chromosome. At necroscopic examination, internal genitalia arising from the genital ridge in the form of masculine type structures were found, while those deriving from the Mullerian ducts were of feminine type. In addition, an infundibular portion of the salpinx at the cranial pole of the gonads was found. This is the first case in equine species of DSD 2n = 64,XX SRY-negative, with the simultaneous presence of male (hypoplastic testicles, epididymal portions, and a penis-like structure) and female (cervix, horn and body of a hypoplastic uterus) genital structures

Editorial: Advances in transoral approaches for laryngeal cancer

status: publishe

¿Cómo construye su tela en forma de embudola araña lobo Aglaoctenus lagotis (Araneae: Lycosidae)?

Construir telas para vivir es raro en las arañas lobo, que suelen tener hábitos errantes. Sin embargo, algunas especies, postuladas como basales dentro del grupo, viven en telas (Foelix, 2011). Se desconoce cómo hace esta especie, y las escasas restantes constructoras de la familia, para tejer los embudos. Sólo hay datos fragmentarios de un licósido de Norteamérica (Prestwich, 1977), con los que A. lagotis, parece diferir notoriamente, al menos en observaciones preliminares. Aglaoctenus lagotis es una de esas especies. Habita en Sudamérica y desarrolla todos sus estadios de vida en telas en forma de embudo (Sordi, 1996; Santos & Brescovit, 2001).Fil: González, Macarena. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Consejo Nacional de Investigaciones Científicas y Técnicas. Laboratorio de Biología Reproductiva y Evolución, Cátedra de Diversidad Animal I; Argentina.Fil: González, Macarena. Laboratorio de Etología, Ecología y Evolución; Uruguay.Fil: Peretti, Alfredo V. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Consejo Nacional de Investigaciones Científicas y Técnicas. Laboratorio de Biología Reproductiva y Evolución, Cátedra de Diversidad Animal I; Argentina.Fil: Costa, Fernando G. Laboratorio de Etología, Ecología y Evolución; Uruguay.Zoología, Ornitología, Entomología, Etologí