Peri-implant bone loss of dental implants with platform-switching design after 5 years of loading: a cross-sectional study

OBJECTIVE The aim of this cross-sectional study was to estimate bone loss of implants with platform-switching design and analyze possible risk indicators after 5 years of loading in a multi-centered private practice network. METHOD AND MATERIALS Peri-implant bone loss was measured radiographically as the distance from the implant shoulder to the mesial and distal alveolar crest, respectively. Risk factor analysis for marginal bone loss included type of implant prosthetic treatment concept and dental status of the opposite arch. RESULTS A total of 316 implants in 98 study patients after 5 years of loading were examined. The overall mean value for radiographic bone loss was 1.02 mm (SD ± 1.25 mm, 95% CI 0.90- 1.14). Correlation analyses indicated a strong association of peri-implant bone loss > 2 mm for removable implant-retained prostheses with an odds ratio of 53.8. CONCLUSION The 5-year-results of the study show clinically acceptable values of mean bone loss after 5 years of loading. Implant-supported removable prostheses seem to be a strong co-factor for extensive bone level changes compared to fixed reconstructions. However, these results have to be considered for evaluation of the included special cohort under private dental office conditions.

siRNA mediated knockdown of tissue factor expression in pigs for xenotransplantation.

Acute vascular rejection (AVR), in particular microvascular thrombosis, is an important barrier to successful pig-to-primate xenotransplantation. Here, we report the generation of pigs with decreased tissue factor (TF) levels induced by small interfering (si)RNA-mediated gene silencing. Porcine fibroblasts were transfected with TF-targeting small hairpin (sh)RNA and used for somatic cell nuclear transfer. Offspring were analyzed for siRNA, TF mRNA and TF protein level. Functionality of TF downregulation was investigated by a whole blood clotting test and a flow chamber assay. TF siRNA was expressed in all twelve liveborn piglets. TF mRNA expression was reduced by 94.1 ± 4.7% in TF knockdown (TFkd) fibroblasts compared to wild-type (WT). TF protein expression in PAEC stimulated with 50 ng/mL TNF-α was significantly lower in TFkd pigs (mean fluorescence intensity TFkd: 7136 ± 136 vs. WT: 13 038 ± 1672). TF downregulation significantly increased clotting time (TFkd: 73.3 ± 8.8 min, WT: 45.8 ± 7.7 min, p < 0.0001) and significantly decreased thrombus formation compared to WT (mean thrombus coverage per viewing field in %; WT: 23.5 ± 13.0, TFkd: 2.6 ± 3.7, p < 0.0001). Our data show that a functional knockdown of TF is compatible with normal development and survival of pigs. TF knockdown could be a valuable component in the generation of multi-transgenic pigs for xenotransplantation.

Effects of Forskolin on Trefoil factor 1 expression in cultured ventral mesencephalic dopaminergic neurons

Trefoil factor 1 (TFF1) belongs to a family of secreted peptides that are mainly expressed in the gastrointestinal tract. Notably, TFF1 has been suggested to operate as a neuropeptide, however, its specific cellular expression, regulation and function remain largely unknown. We have previously shown that TFF1 is expressed in developing and adult rat ventral mesencephalic tyrosine hydroxylase-immunoreactive (TH-ir) dopaminergic neurons. Here, we investigated the expression of TFF1 in rat ventral mesencephalic dopaminergic neurons (embryonic day 14) grown in culture for 5, 7 or 10 days in the absence (controls) or presence of either glial cell line-derived neurotrophic factor (GDNF), Forskolin or the combination. No TFF1-ir cells were identified at day 5 and only a few at day 7, whereas TH was markedly expressed at both time points. At day 10, several TFF1-ir cells were detected, and their numbers were significantly increased after the addition of GDNF (2.2-fold) or Forskolin (4.1-fold) compared to controls. Furthermore, the combination of GDNF and Forskolin had an additive effect and increased the number of TFF1-ir cells by 5.6-fold compared to controls. TFF1 expression was restricted to neuronal cells, and the percentage of TH/TFF1 co-expressing cells was increased to the same extent in GDNF and Forskolin-treated cultures (4-fold) as compared to controls. Interestingly, the combination of GDNF and Forskolin resulted in a significantly increased co-expression (8-fold) of TH/TFF1, which could indicate that GDNF and Forskolin targeted different subpopulations of TH/TFF1 neurons. Short-term treatment with Forskolin resulted in an increased number of TFF1-ir cells, and this effect was significantly reduced by the MEK1 inhibitor PD98059 or the protein kinase A (PKA) inhibitor H89, suggesting that Forskolin induced TFF1 expression through diverse signaling pathways. In conclusion, distinct populations of cultured dopaminergic neurons express TFF1, and their numbers can be increased by factors known to influence survival and differentiation of dopaminergic cells.

CHARACTERIZATION OF THE COLONIZATION FACTOR ANTIGEN II PLASMID (CFA/II) FROM ENTEROTOXIGENIC ESCHERICHIA COLI

The etiological role of enterotoxigenic E. coli (ETEC) in diarrheal diseases of man and domestic animals is firmly established. Besides the production of enterotoxins (ST and LT), ETEC produces other important virulence factors; the colonization factor antigens (CFAs). CFAs mediate the attachment of ETEC to the epithelial cells of the small intestine, and this favors colonization by the bacteria and facilitates delivery of the enterotoxins to the intestinal cells.^ The production of enterotoxin and CFA is determined by plasmids and has been found to be restricted to a select number of E. coli serotypes.^ In this work, plasmid DNA analysis was performed in twenty-three CFA/II-producing enterotoxigenic Escherichia coli strains and their spontaneous CFA/II-negative derivatives. In some cases, strains lost the high molecular weight plasmid and also the ability to produce CFA/II, ST and LT. In other cases there was a deletion of the plasmid, which produced strains that were CFA/II('-), ST('-), LT('-) or CFA/II('-), ST('+), LT('+).^ The CFA/II plasmid from strain PB-176 (06:H16:CFA/II('+), ST('+), LT('+)) was transferred by transformation into E. coli K12 with concomitant transfer of the three characteristics: CFA/II, ST and LT.^ A physical map of the prototype CFA/II:ST:LT (pMEP60) plasmid was constructed by restriction endonuclease analysis and compared to plasmids from three other CFA/II-producing strains. A CFA/II-negative (but ST and LT positive) deletion derivative of pMEP60 (pMEP30) was also included in the map. The four CFA/II plasmids analyzed had a common region of approximately 30 kilobase pairs. The toxin genes were approximately 5 kbp apart and about 20 kbp from the common region. The information given by this physical map could be of great value when constructing a clone that will express the CFA/II genes but not the toxin genes. ^

An extracytoplasmic function sigma factor operon regulates Myxococcus xanthus developmental gene expression

Myxococcus xanthus is a Gram-negative soil bacterium that undergoes multicellular development when high-density cells are starved on a solid surface. Expression of the 4445 gene, predicted to encode a periplasmic protein, commences 1.5 h after the initiation of development and requires starvation and high density conditions. Addition of crude or boiled supernatant from starving high-density cells restored 4445 expression to starving low-density cells. Addition of L-threonine or L-isoleucine to starving low-density cells also restored 4445 expression, indicating that the high-density signaling activity present in the supernatant might be composed of extracellular amino acids or small peptides. To investigate the circuitry integrating these starvation and high-density signals, the cis- and trans-acting elements controlling 4445 expression were identified. The 4445 transcription start site was determined by primer extension analysis to be 58 by upstream of the predicted translation start site. The promoter region contained a consensus sequence characteristic of e&barbelow;xtrac&barbelow;ytoplasmic f&barbelow;unction (ECF) sigma factor-dependent promoters, suggesting that 4445 expression might be regulated by an ECF sigma factor-dependent pathway, which are known to respond to envelope stresses. The small size of the minimum regulatory region, identified by 5′-end deletion analysis as being only 66 by upstream of the transcription start site, suggests that RNA polymerase could be the sole direct regulator of 4445 expression. To identify trans-acting negative regulators of 4445 expression, a strain containing a 4445-lacZ was mutagenized using the Himar1-tet transposon. The four transposon insertions characterized mapped to an operon encoding a putative ECF sigma factor, ecfA; an anti-sigma factor, reaA; and a negative regulator, reaB. The reaA and the reaB mutants expressed 4445 during growth and development at levels almost 100-fold higher than wild type, indicating that these genes encode negative regulators. The ecfA mutant expressed 4445-lacZ at basal levels, indicating that ecfA is a positive regulator. High Mg2+ concentrations over-stimulated this ecfA pathway possibly due to the depletion of exopolysaccharides and assembled type IV pili. These data indicate that the ecfA operon encodes a new regulatory stress pathway that integrates and transduces starvation and cell density cues during early development and is also responsive to cell-surface alterations.^

Childhood sexual victimization: Risk factor for drug use and sexual risk behaviors

The purpose of this dissertation was to survey men in the Harris County Jail (HCJ) to establish a more valid estimate of childhood sexual abuse (CSA) prevalence in a jailed-based population; to assess whether inmates with a history of CSA were at greater risk for use of drugs and alcohol and engaging in high-risk sexual behaviors than those without histories of childhood sexual abuse. ^ The first study determined the prevalence of childhood sexual abuse among incarcerated males in a county jail. In this study, sixty-three percent of the subjects reported having been sexually abused. Sixty-one percent reported abuse pre-puberty and 10% reported abuse post puberty. In pre-puberty abuse the initiation of first abuse occurred at a mean age of 5.6 years (SD 5.096, range: 2–13 years). ^ The second study explored the association between inmates with histories of CSA as a risk factor for sexual risk behaviors. A history of sexual abuse did not appear to be associated with an elevated risk of sexual risk behaviors. ^ The third study explored a history of drug use and a history of CSA among the inmates. A chi-square test showed that the inmates who reported a history of CSA, was significantly greater for the following drugs: Marijuana (02), Crack (03), Heroin/Morphine (.03), Amphetamines/Speed (01), Downers/Barbiturates (.001), Methamphetamine/Crystal Meth (.001), Valium .02), LSD/Acid (.001), and Inhalants (.001), p < .05). Significance was not found in alcohol, tobacco, cocaine, Quaaludes and methadone. ^ The research from this study provides empirical data supporting previous research. The current data shows that incarcerated inmates have a high prevalence of childhood sexual abuse and drug use. Sexual victimization as a child does not appear to be associated with an elevated risk of unsafe sexual behaviors. However, men who used drugs were twice as likely to have engaged in unprotected sex with casual and regular partners, and rarely used condoms with paid sex. Although our study methods do not permit a causal explanation for this association, we believe it is of concern. Finally, data in this study shows that sexually abused children are likely candidates for adult criminal behavior. ^

A mechanism of insulin-like growth factor binding protein 2-induced cell mobility in glioma

Insulin-like growth factor binding protein 2 (IGFBP2) is a protein known to be overexpressed in a majority of glioblastoma multiforme (GBM) tumors. While it is known the IGFBP2 is involved in promoting GBM tumor cell invasion, no mechanism exists for how the protein is involved in signal transduction pathways leading to enhanced cell invasion. ^ We follow up on preliminary microarray data on IGFBP2-overexpressing GBM cells and protein sequence analysis of IGFBP2 in generating the hypothesis that IGFBP2 interacts with integnn α5 in regulating cell mobility. Microarray data showing upregulation of integrin α5 by IGFBP2 is validated and evidence of protein-protein interaction between IGFBP2 and integrin α5 is found. The exact binding domain on IGFBP2 responsible for its interaction with integrin α5 is also determined, confirming our initial findings and reaffirming that the IGFBP2/integrin α5 interaction is specific. Disruption of this interaction resulted in attenuation of IGFBP2-enhanced cell mobility. Further, we found that cell mobility is only enhanced when IGFBP2 and integrin α5 are both overexpressed and able to interact with each other. ^ We also determined fibronectin to be a critical player in the activation of the IGFBP2/integrin α5 pathway. The activation of this pathway appears to be progressive and initiates once GBM cells have sufficiently established anchorage. ^

Incident hypertension among pre-hypertensive adolescents: Evaluation of pre-hypertension as an independent risk factor among secondary school students in the Houston area

Cardiovascular disease has been the leading cause of death in the United States for over fifty years. While multiple risk factors for cardiovascular disease have been identified, hypertension is one of the most commonly recognized and treatable. Recent studies indicate that the prevalence of hypertension among children and adolescents is between 3-5%, much higher than originally estimated and likely rising due to the epidemic of obesity in the U.S. In 2004, the National High Blood Pressure Education Program Working Group on High Blood Pressure in Children and Adolescents published new guidelines for the diagnosis and treatment of hypertension in this population. Included in these recommendations was the creation of a new diagnosis, pre-hypertension, aimed at identifying children at-risk for hypertension to provide early lifestyle interventions in an effort to prevent its ultimate development. In order to determine the risk associated with pre-hypertension for the development of incident HTN, a secondary analysis of a repeated cross-sectional study measuring blood pressure in Houston area adolescents from 2000 to 2007 was performed. Of 1006 students participating in the blood pressure screening on more than one occasion not diagnosed with hypertension at initial encounter, eleven were later found to have hypertension providing an overall incident rate of 0.5% per year. Incidence rates were higher among overweight adolescents–1.9% per year [IRR 8.6 (1.97, 51.63)]; students “at-risk for hypertension” (pre-hypertensive or initial blood pressure in the hypertensive range but falling on subsequent measures)–1.4% per year [IRR 4.77 (1.21, 19.78)]; and those with blood pressure ≥90th percentile on three occasions–6.6% per year [IRR 21.87 (3.40, 112.40)]. Students with pre-hypertension as currently defined by the Task Force did have an increased rate of hypertension (1.1% per year) but it did not reach statistical significance [IRR 2.44 (0.42, 10.18)]. Further research is needed to determine the morbidity and mortality associated with pre-hypertension in this age group as well as the effectiveness of various interventions for preventing the development of hypertensive disease among these at-risk individuals. ^

Regulation of myogenesis and suppression of {\it mck\/} 5$\sp\prime$ enhancer elements by TGF$\beta$ and RAS

The regulation of muscle differentiation, like cell differentiation in general, is only now beginning to be understood. Here are described several key features to myogenesis: a beginning, some intermediary events, and an endpoint. Muscle differentiation proceeds spontaneously when myoblasts are cultured in serum-poor medium. Transforming growth factor type $\beta$ (TGF$\beta$), a component of fetal serum, was found to potently suppress muscle differentiation. Prolonged blockade of differentiation required replenishing TGF$\beta$. When TGF$\beta$ was removed, cells rapidly differentiated. Both TGF$\beta$ and RAS, which also blocks myogenesis, suppress the genes for a series of muscle-specific proteins. Regions that regulate transcription of one such gene, muscle creatine kinase (mck), were located by linking progressively smaller parts of the mck 5$\sp\prime$ region to the marker gene cat and testing the constructs for regulated expression of cat in myoblasts and muscle cells. The mck promoter is not muscle-specific but requires activation. Two enhancers were found: a weak, developmentally regulated enhancer within the first intron, and a strong, compact, and tightly developmentally regulated enhancer about 1.2 Kb upstream of the transcription start site. Activity of this enhancer is eliminated by activated ras. Suppression of activated N-RAS restores potency to the upstream enhancer. Further deletion shows the mck 5$\sp\prime$ enhancer to contain an enhancer core with low but significant muscle-specific activity, and at least one peripheral element that augments core activity. The core and this peripheral element were comprised almost entirely of factor-binding motifs. The peripheral element was inactive as a single copy, but was constitutively active in multiple copies. Regions flanking the peripheral element augmented its activity and conferred partial muscle-specificity. The enhancer core is also modulated by its 5$\sp\prime$ flanking region in a complex manner. Site-specific mutants covering most of the enhancer core and interesting flanking sequences have been made; all mutants tested diminish the activity of the 5$\sp\prime$ enhancer. Alteration of the site to which MyoD1 is reported to bind completely inactivates the enhancer. A theoretical analysis of cooperativity is presented, through which the binding of a constitutively expressed nuclear factor is shown to have weak positive cooperativity. In summary, TGF$\beta$, RAS, and enhancer-binding factors are found to be initial, intermediary, and final regulators, respectively, of muscle differentiation. ^

Cloning and molecular analysis of paraxis: A {\it trans\/}-acting factor required for somite maturation

During vertebrate embryogenesis, cells from the paraxial mesoderm coalesce in a rostral-to-caudal progression to form the somites. Subsequent compartmentalization of the somites yields the sclerotome, myotome and dermatome, which give rise to the axial skeleton, axial musculature, and dermis, respectively. Recently, we cloned a novel basic-Helix-Loop-Helix (bHLH) protein, called scleraxis, which is expressed in the sclerotome, in mesenchymal precursors of bone and cartilage, and in connective tissues. This dissertation focuses on the cloning, expression and functional analysis of a bHLH protein termed paraxis, which is nearly identical to scleraxis within the bHLH region but diverges in both its amino and carboxyl termini. During the process of mouse embryogenesis, paraxis transcripts are first detected at about day 7.5 post coitum within the primitive mesoderm lying posterior to the head and heart primordia. Subsequently, paraxis expression progresses caudally through the paraxial mesoderm, immediately preceding somite formation. Paraxis is expressed at high levels in newly formed somites before the first detectable expression of the myogenic bHLH genes, and as the somite becomes compartmentalized, paraxis becomes downregulated within the myotome.^ To determine the function of paraxis during mammalian embryogenesis, mice were generated with a null mutation in the paraxis locus. Paraxis null mice survived until birth, but exhibited severe foreshortening along the anteroposterior axis due to the absence of vertebrae caudal to the midthoracic region. The phenotype also included axial skeletal defects, particularly shortened bifurcated ribs which were detached from the vertebral column, fused vertebrae and extensive truncation and disorganization caudal to the hindlimbs. Mutant neonates also lacked normal levels of trunk muscle and exhibited defects in the dermis as well as the stratification of the epidermis. Analysis of paraxis -/- mutant embryos has revealed a failure of the somites to both properly epithelialize and compartmentalize, resulting in defects in somite-derived cell lineages. These results suggest that paraxis is an essential component of the genetic pathway regulating somitogenesis. ^

La época de raleo como factor de rentabilidad en duraznos conserveros de maduración temprana

Del total de la superficie implantada con duraznos conserveros en la provincia de Mendoza, el 27% corresponde a cultivares de maduración temprana, en los que el raleo de frutos es un factor crítico de manejo. Para determinar la incidencia de diferentes épocas de raleo sobre la rentabilidad del cultivo se realizó un ensayo en un monte comercial de durazneros cvs. Fortuna y Carson. Se utilizaron árboles injertados sobre portainjerto Nemaguard, conducidos en vaso tipo californiano e implantados a 6 m entre hileras y a 5 m entre plantas, que fueron raleados en tres épocas diferentes: a los 40 días después de plena floración, en inicio de endurecimiento de carozo y 10 días después, en la fecha de referencia. Se realizaron evaluaciones de producción por planta y calidad de frutos. También se determinó el valor de la producción y la relación entre éste y las distintas fechas de raleo. En ambos cultivares, los árboles raleados en época temprana obtuvieron mayor peso de frutos, producción total y producción destinada a mitades. En el cv. Fortuna, este tratamiento produjo un aumento significativo del porcentaje de frutos con carozo partido.El raleo temprano de frutos aumentó significativamente el valor de la cosecha, logrando un incremento de $ 3636.ha-1 y $ 3441.ha-1en los cvs. Fortuna y Carson, respectivamente, en relación con el tratamiento en fecha de referencia.

Determinación de la actividad de la óxido nítrico sintetasa endotelial y del factor NF-kB, en la piel del paciente con pseudoangiomatosis eruptiva : informe preliminar

La pseudoangiomatosis eruptiva se caracteriza por la aparición brusca de múltiples pápulas eritematosas, asintomáticas, rodeadas de un halo blanquecino, con remisión espontánea. Histológicamente se observa dilatación vascular con escaso infiltrado inflamatorio. Su etiología permanece incierta a pesar de ser relacionada con virus o picaduras de insectos. Basados en el compromiso vascular, el objetivo del trabajo fue investigar la actividad de la enzima endotelial oxido nítrico sintetasa (eNOS) y la expresión del factor NF-kB por inmunohistoquimica en un intento de esclarecer su patogenia. Material y métodos: Se estudiaron diez pacientes con diagnóstico clínico de pseudoangiomatosis eruptiva (PAE) que presentaron la dermatosis en forma epidémica. Se realizaron biopsias teñidas con Hematoxilina-Eosina y Tricrómico de Masson. Se efectuó estudio virológico de los pacientes Nª 4, 9 y 10 mediante determinaciones serológicas para echovirus, enterovirus, citomegalovirus, parvovirus B19 y hepatitis A, B y C. En cinco pacientes se obtuvo material para determinación de eNOS y NF-kB. Resultados: Todos los pacientes, 5 hombres y 5 mujeres presentaron pápulas eritematosas rodeadas por un halo blanquecino, especialmente en las extremidades, alrededor de las rodillas. Histológicamente mostraron vasos dilatados y células endoteliales prominentes con un infiltrado discreto perivascular. Todos los estudios serológicos fueron negativos. La actividad de eNOS fue significativamente menor comparada con la piel normal (p= 0,002) y la expresión de NF- ĸB fue fuertemente positiva en los vasos de la dermis papilar y reticular. Conclusiones: Todos los pacientes fueron afectados en verano, por lo que la picadura del mosquito debe ser considerada como un factor etiológico. La baja expresión de eNOS está relacionada con la vasodilatación y la expresión aumentada de NF-ĸB confirma que el proceso es de tipo inflamatorio.

Ricardo Rojas y el factor estudiantil en la fundación de la Universidad de Cuyo

Fil: Fontana de García, María B..

Ricardo Rojas y el factor estudiantil en la Fundación de la Universidad Nacional de Cuyo

Fil: Fontana de García, María B..

Ricardo Rojas y el factor estudiantil en la Fundación de la Universidad Nacional de Cuyo

Fil: Fontana de García, María B..