Novel Strategy To Adapt Simian-Human Immunodeficiency Virus E1 Carrying env from an RV144 Volunteer to Rhesus Macaques: Coreceptor Switch and Final Recovery of a Pathogenic Virus with Exclusive R5 Tropism.

The phase III RV144 human immunodeficiency virus (HIV) vaccine trial conducted in Thailand remains the only study to show efficacy in decreasing the HIV acquisition risk. In Thailand, circulating recombinant forms of HIV clade A/E (CRF01_AE) predominate; in such viruses, env originates from clade E (HIV-E). We constructed a simian-human immunodeficiency virus (SHIV) chimera carrying env isolated from an RV144 placebo recipient in the SHIV-1157ipd3N4 backbone. The latter contains long terminal repeats (LTRs) with duplicated NF-κB sites, thus resembling HIV LTRs. We devised a novel strategy to adapt the parental infectious molecular clone (IMC), R5 SHIV-E1, to rhesus macaques: the simultaneous depletion of B and CD8+ cells followed by the intramuscular inoculation of proviral DNA and repeated administrations of cell-free virus. High-level viremia and CD4+ T-cell depletion ensued. Passage 3 virus unexpectedly caused acute, irreversible CD4+ T-cell loss; the partially adapted SHIV had become dual tropic. Virus and IMCs with exclusive R5 tropism were reisolated from earlier passages, combined, and used to complete adaptation through additional macaques. The final isolate, SHIV-E1p5, remained solely R5 tropic. It had a tier 2 neutralization phenotype, was mucosally transmissible, and was pathogenic. Deep sequencing revealed 99% Env amino acid sequence conservation; X4-only and dual-tropic strains had evolved independently from an early branch of parental SHIV-E1. To conclude, our primate model data reveal that SHIV-E1p5 recapitulates important aspects of HIV transmission and pathobiology in humans.IMPORTANCE Understanding the protective principles that lead to a safe, effective vaccine against HIV in nonhuman primate (NHP) models requires test viruses that allow the evaluation of anti-HIV envelope responses. Reduced HIV acquisition risk in RV144 has been linked to nonneutralizing IgG antibodies with a range of effector activities. Definitive experiments to decipher the mechanisms of the partial protection observed in RV144 require passive-immunization studies in NHPs with a relevant test virus. We have generated such a virus by inserting env from an RV144 placebo recipient into a SHIV backbone with HIV-like LTRs. The final SHIV-E1p5 isolate, grown in rhesus monkey peripheral blood mononuclear cells, was mucosally transmissible and pathogenic. Earlier SHIV-E passages showed a coreceptor switch, again mimicking HIV biology in humans. Thus, our series of SHIV-E strains mirrors HIV transmission and disease progression in humans. SHIV-E1p5 represents a biologically relevant tool to assess prevention strategies.

Evidence of collective influence in innate sensing using fluidic force microscopy.

The innate immune system initiates early response to infection by sensing molecular patterns of infection through pattern-recognition receptors (PRRs). Previous work on PRR stimulation of macrophages revealed significant heterogeneity in single cell responses, suggesting the importance of individual macrophage stimulation. Current methods either isolate individual macrophages or stimulate a whole culture and measure individual readouts. We probed single cell NF-κB responses to localized stimuli within a naïve culture with Fluidic Force Microscopy (FluidFM). Individual cells stimulated in naïve culture were more sensitive compared to individual cells in uniformly stimulated cultures. In cluster stimulation, NF-κB activation decreased with increased cell density or decreased stimulation time. Our results support the growing body of evidence for cell-to-cell communication in macrophage activation, and limit potential mechanisms. Such a mechanism might be manipulated to tune macrophage sensitivity, and the density-dependent modulation of sensitivity to PRR signals could have relevance to biological situations where macrophage density increases.

Protocol for localized macrophage stimulation with small-molecule TLR agonist via fluidic force microscopy.

Here, we present a protocol to deliver nanoliter volumes of Toll-like receptor (TLR) agonist onto a culture of nuclear factor κB (NF-κB) reporter macrophages using fluidic force microscopy and a micron-scale probe. We describe steps for quantifying the dose of agonist by modeling their diffusion with experimental inputs. We then detail procedures for quantifying and categorizing macrophage responses to individual and varied doses and combining agonist concentration and macrophage response to analyze the NF-κB response to localized TLR stimulation. For complete details on the use and execution of this protocol, please refer to Mulder et al. (2024).1.

Age associated susceptibility to SARS-CoV-2 infection in the K18-hACE2 transgenic mouse model.

Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is still an ongoing global health crisis. Clinical data indicate that the case fatality rate (CFR) is age dependent, with a higher CFR percentage in the elderly population. We compared the pathogenesis of SARS-CoV-2 in young and aged K18-hACE2 transgenic mice. We evaluated morbidity, mortality, viral titers, immune responses, and histopathology in SARS-CoV-2-infected young and old K18-hACE2 transgenic mice. Within the limitation of having a low number of mice per group, our results indicate that SARS-CoV-2 infection resulted in slightly higher morbidity, mortality, and viral replication in the lungs of old mice, which was associated with an impaired IgM response and altered cytokine and chemokine profiles. Results of this study increase our understanding of SARS-CoV-2 infectivity and immuno-pathogenesis in the elderly population.

Role of multimodality cardiac imaging for evaluation of intramyocardial dissection, from dissecting haematoma to false-pseudoaneurysm: a case series.

Background: Intramyocardial dissection (ID) is an extremely rare myocardial infarction mechanical complication. Although both clinical and imaging assessment of this rare condition remains a challenge, recent multimodality imaging techniques may help to confirm and to assess the progressive nature of the disease. Diagnosis may be reached in different stages, from as early as the intramyocardial dissecting haematoma to the severe false-pseudoaneurysm. Case summary: This series describes five cases of ID and provides insights into imaging findings and clinical course of this extremely uncommon condition. Our patients represented a wide range of clinical stages, from asymptomatic course to cardiogenic shock. The imaging diagnostic approach was very different from case to case and involved techniques such as echocardiography, cardiac CT, and cardiac magnetic resonance. Discussion: Intramyocardial dissection is a challenging condition in terms of diagnosis and clinical management associated with high morbidity and mortality. Furthermore, the different nomenclature found in the literature may be confusing. This case series supports the need of a terminology standardization and a multimodal imaging approach, which might be determinant for an accurate differential diagnosis and a suitable therapeutic management.

Extracellular Delivery of Functional Mitochondria Rescues the Dysfunction of CD4+ T Cells in Aging.

Mitochondrial dysfunction alters cellular metabolism, increases tissue oxidative stress, and may be principal to the dysregulated signaling and function of CD4+ T lymphocytes in the elderly. In this proof of principle study, it is investigated whether the transfer of functional mitochondria into CD4+ T cells that are isolated from old mice (aged CD4+ T cells), can abrogate aging-associated mitochondrial dysfunction, and improve the aged CD4+ T cell functionality. The results show that the delivery of exogenous mitochondria to aged non-activated CD4+ T cells led to significant mitochondrial proteome alterations highlighted by improved aerobic metabolism and decreased cellular mitoROS. Additionally, mito-transferred aged CD4+ T cells showed improvements in activation-induced TCR-signaling kinetics displaying markers of activation (CD25), increased IL-2 production, enhanced proliferation ex vivo. Importantly, immune deficient mouse models (RAG-KO) showed that adoptive transfer of mito-transferred naive aged CD4+ T cells, protected recipient mice from influenza A and Mycobacterium tuberculosis infections. These findings support mitochondria as targets of therapeutic intervention in aging.

Aerosolized sulfated hyaluronan derivatives prolong the survival of K18 ACE2 mice infected with a lethal dose of SARS-CoV-2.

Despite several vaccines that are currently approved for human use to control the pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), there is an urgent medical need for therapeutic and prophylactic options. SARS-CoV-2 binding and entry in human cells involves interactions of its spike (S) protein with several host cell surface factors, including heparan sulfate proteoglycans (HSPGs), transmembrane protease serine 2 (TMPRSS2), and angiotensin-converting enzyme 2 (ACE2). In this paper we investigated the potential of sulphated Hyaluronic Acid (sHA), a HSPG mimicking polymer, to inhibit the binding of SARS-CoV-2 S protein to human ACE2 receptor. After the assessment of different sulfation degree of sHA backbone, a series of sHA functionalized with different hydrophobic side chains were synthesized and screened. The compound showing the highest binding affinity to the viral S protein was further characterized by surface plasmon resonance (SPR) towards ACE2 and viral S protein binding domain. Selected compounds were formulated as solutions for nebulization and, after being characterized in terms of aerosolization performance and droplet size distribution, their efficacy was assessed in vivo using the K18 human (h)ACE2 transgenic mouse model of SARS-CoV-2 infection.

Impact of intraventricular hemorrhage upon intracerebral hematoma expansion.

BACKGROUND: The purpose of this study is to determine whether intraventricular hemorrhage (IVH) exerts a "decompressive" effect that limits intracerebral hemorrhage (ICH) enlargement. METHODS: Retrospective review of patients with spontaneous supratentorial ICH diagnosed within 6 h of onset, who underwent follow-up head CT approximately 48 h later. Digital imaging analysis of CT scans was performed to compare hematoma volume changes between patients with and without IVH. Hemorrhage locations were classified as paraventricular (PV) or non-PV. Regression analyses were employed to identify predictors of IVH, hematoma expansion, and mortality. RESULTS: Of the 70 patients included 57% developed IVH, 85% of which occurred before initial CT. 71% of PV hemorrhages developed IVH, all before initial CT, and 48% of non-PV hemorrhages developed IVH, 29% of which occurred after initial CT. IVH was associated with PV location (P = 0.04), and among IVH patients PV location was associated with early IVH (P = 0.003). Predictors of mortality included age (P = 0.037), initial hematoma volume (P < 0.04), absolute volume change (P = 0.01), and final hematoma volume (P < 0.001). Variables predicting IVH included PV location (P < 0.0001), larger initial hematoma volume (P = 0.002), and greater absolute volume increase (P = 0.01). Hematoma expansion was greatest for non-PV with IVH (P = 0.08), and graphic inspection suggested that ICH volume tended to decrease with PV location and increase with IVH. Final hematoma volume was associated with initial volume (P < 0.0001), non-PV location (P = 0.02), and IVH (P = 0.04). CONCLUSIONS: IVH was not associated with less hematoma volume expansion, and for non-PV hemorrhages IVH was linked to greater volume increase.

Antiviral activity of oleandrin and a defined extract of Nerium oleander against SARS-CoV-2.

With continued expansion of the coronavirus disease (COVID-19) pandemic, caused by severe acute respiratory syndrome 2 (SARS-CoV-2), both antiviral drugs as well as effective vaccines are desperately needed to treat patients at high risk of life-threatening disease. Here, we present in vitro evidence for significant inhibition of SARS-CoV-2 by oleandrin and a defined extract of N. oleander (designated as PBI-06150). Using Vero cells, we found that prophylactic (pre-infection) oleandrin (as either the pure compound or as the active principal ingredient in PBI-06150) administration at concentrations as low as 0.05 µg/ml exhibited potent antiviral activity against SARS-CoV-2, with an 800-fold reduction in virus production, and a 0.1 µg/ml concentration resulted in a greater than 3000-fold reduction in infectious virus production. The half maximal effective concentration (EC50) values were 11.98 ng/ml when virus output was measured at 24 h post-infection, and 7.07 ng/ml measured at 48 h post-infection. Therapeutic (post-infection) treatment up to 24 h after SARS-CoV-2 infection of Vero cells also reduced viral titers, with 0.1 µg/ml and 0.05 µg/ml concentrations causing greater than 100-fold reduction as measured at 48 h, and the 0.05 µg/ml concentration resulting in a 78-fold reduction. Concentrations of oleandrin up to 10 µg/ml were well tolerated in Vero cells. We also present in vivo evidence of the safety and efficacy of defined N. oleander extract (PBI-06150), which was administered to golden Syrian hamsters in a preparation containing as high as 130 µg/ml of oleandrin. In comparison to administration of control vehicle, PBI-06150 provided a statistically significant reduction of the viral titer in the nasal turbinates (nasal conchae). The potent prophylactic and therapeutic antiviral activities demonstrated here, together with initial evidence of its safety and efficacy in a relevant hamster model of COVID-19, support the further development of oleandrin and/or defined extracts containing this molecule for the treatment of SARS-CoV-2 and associated COVID-19 disease and potentially also for reduction of virus spread by persons diagnosed early after infection.

Role of antiplatelet agents in hematoma expansion during the acute period of intracerebral hemorrhage.

BACKGROUND: Oral anticoagulants have been associated with greater hematoma expansion in patients with intracerebral hemorrhage (ICH). The purpose of this study was to determine whether the reported use of antiplatelet agents also results in greater hematoma expansion. METHODS: Retrospective review of patients with spontaneous supratentorial ICH diagnosed within 6 h of onset, who underwent follow-up head CT approximately 48 h later. Digital imaging analysis of initial and second CT scans was performed for comparison of hematoma volume changes between patients reporting and those not reporting antecedent antiplatelet use. Statistical analyses to determine predictors of ICH volume change and in-hospital mortality were also performed via multivariate regression models. RESULTS: Of the 70 patients included, 17 were documented as taking antiplatelet agents. Groups were comparable regarding baseline demographic, clinical and laboratory characteristics, and the timing of CT scans was similar. Patients reporting antiplatelet use experienced greater absolute increase (7.7 ml vs. 5.5 ml) and proportional increase (110% vs. 21%) in ICH volume than those not reporting antiplatelet use, but these differences were not statistically significant (P = 0.94 and 0.61 respectively; Wilcoxon test). Baseline hematoma volume tended to correlate with percentage volume increase (P < 0.1), whereas IVH was inversely associated with percent volume increase (P < 0.05). Age (P < 0.05), absolute volume increase (P < 0.005), and final volume (P < 0.001) were associated with in-hospital mortality, the rates of which were similar between the two study groups (18% vs. 17%). CONCLUSIONS: Patients reporting antiplatelet use experienced similar degrees of hematoma expansion compared to patients not reporting antiplatelet use.

A Nursing Workforce Initiative: Increasing the Latino/Hispanic BSN Workforce.

Of the 3 million nurses in the United States, only 5.4% of registered nurses are Latinos. This is a grave concern since the U.S. Census' projected increase of Latinos in the United States is expected to be 28% by 2060. In 2010, the Institute of Medicine report recommended a diverse workforce in health care to improve health outcomes. However, the increase in the Latino nursing workforce continues to be low compared to with the population of Latinos in the country. The National Association of Hispanic Nurses and the University of Alabama partnered to increase the number of baccalaureate-prepared registered nurses in the workforce. BAMA-Latino Project (BAMA-L) is a Health Resources and Services Administration-funded program to increase the diversity of registered nurses in the nursing workforce. The purpose of this article is to present the development and implementation of BAMA-L.

[Pott's Disease in Upper Thoracic Vertebrae in a Two-Year-Old Boy: Case Report]. / Reporte de caso de enfermedad de Pott en vértebras torácicas altas en un niño de dos años.

Pott's disease is a health problem in developing countries and its diagnosis in children is a challenge. Here we present the case of a two-year-old boy with Pott's disease involving T1 to T3 thoracic vertebrae. The clinical presentation was characterized by difficulty walking, fever, cough, and dyspnea. At physical examination, kyphosis and bony prominence were observed in the cervicodorsal area. A positive tuberculin test was obtained, and Mycobacterium tuberculosis was isolated via culture of the gastric aspiration sample. The spine MRI showed a chronic abscess, destruction of two vertebrae, and bone marrow compression. The patient experienced some improvement with anti-TB therapy. Here, we emphasize the importance of giving consideration to the clinical suspicion for the early detection of this condition, as well as a quick TB-treatment start so as to avoid the disability and mortality associated to this disease.

La enfermedad de Pott es un problema de salud en países en desarrollo y su diagnóstico en niños es un desafío. Presentamos el caso de un niño de dos años de edad, con enfermedad de Pott que compromete vértebras torácicas de T1 a T3. El cuadro clínico se caracterizó por dificultad para caminar, fiebre, tos y disnea. Al examen físico, se evidenció cifosis y prominencia ósea en la región cervicodorsal. Se obtuvo una prueba de tuberculina positiva y se aisló Mycobacterium tuberculosis en el cultivo del aspirado gástrico. La resonancia de columna vertebral mostró un absceso frio, destrucción de dos vértebras y compresión de la médula espinal. El paciente presentó mejoría con la terapia antituberculosa. Resaltamos la importancia de tener en cuenta la sospecha clínica para la detección temprana de esta condición, así como un inicio rápido del tratamiento antituberculoso, para evitar la discapacidad y mortalidad asociada a esta enfermedad.

Kynurenine pathway metabolic balance influences microglia activity: Targeting kynurenine monooxygenase to dampen neuroinflammation.

Chronic stress or inflammation increases tryptophan metabolism along the kynurenine pathway (KP), and the generation of neuroactive kynurenine metabolites contributes to subsequent depressive-like behaviors. Microglia regulate KP balance by preferentially producing oxidative metabolites, including quinolinic acid. Research has focused on the interplay between cytokines and HPA axis-derived corticosteroids in regulating microglial activity and effects of KP metabolites directly on neurons; however, the potential role that KP metabolites have directly on microglial activity is unknown. Here, murine microglia were stimulated with lipopolysaccharide(LPS). After 6 h, mRNA expression of interleukin(IL)-1ß, IL-6, tumor necrosis factor(TNF)-α and inducible nitric oxide synthase(iNOS) was dose-dependently increased along with the rate-limiting enzymes for oxidative KP metabolism, indoleamine-2,3-dioxygenase(IDO)-1 and kynurenine 3-monooxygenase(KMO). By 24 h post-LPS, kynurenine and quinolinic acid in the media was elevated. Inhibiting KMO with Ro 61-8048 during LPS challenge attenuated extracellular nitrite accumulation and expression of KMO and TNF-α in response to LPS. Similarly, primary microglia isolated from KMO-/- mice exhibited a significantly reduced pro-inflammatory response to LPS compared to WT controls. To determine whether the substrate (kynurenine) or end product (quinolinic acid) of KMO-dependent metabolism modulates the LPS response, microglia were treated with increasing concentrations of L-kynurenine or quinolinic acid in combination with LPS or saline. Interestingly, quinolinic acid did not impact the microglial LPS response. However, L-kynurenine had dose-dependent inhibitory effect on the LPS response. These data are the first to show an anti-inflammatory effect of KMO inhibition on microglia during immune challenge and suggest that KP metabolic balance may play a direct role in regulating microglia activity.

Closed-Loop Communication Improves Task Completion in Pediatric Trauma Resuscitation.

BACKGROUND: Pediatric trauma care requires effective and clear communication in a time-sensitive manner amongst a variety of disciplines. Programs such as Crew Resource Management in aviation have been developed to systematically prevent errors. Similarly, teamSTEPPS has been promoted in healthcare with a strong focus on communication. We aim to evaluate the ability of closed-loop communication to improve time-to-task completion in pediatric trauma activations. METHODS: All pediatric trauma activations from January to September, 2016 at an American College of Surgeons verified level I pediatric trauma center were video recorded and included in the study. Two independent reviewers identified and classified all verbal orders issued by the trauma team leader for order audibility, directed responsibility, check-back, and time-to-task-completion. The impact of pre-notification and level of activation on time-to-task-completion was also evaluated. All analyses were performed using SAS® version 9.4(SAS Institute Inc., Cary, NC). RESULTS: In total, 89 trauma activation videos were reviewed, with 387 verbal orders identified. Of those, 126(32.6%) were directed, 372(96.1%) audible, and 101(26.1%) closed-loop. On average each order required 3.85 minutes to be completed. There was a significant reduction in time-to-task-completion when closed-loop communication was utilized (p < 0.0001). Orders with closed-loop communication were completed 3.6 times sooner as compared to orders with an open-loop [HR = 3.6 (95% CI: 2.5, 5.3)]. There was not a significant difference in time-to-task-completion with respect to pre-notification by emergency service providers (p < 0.6100). [HR = 1.1 (95% CI: 0.9, 1.3)]. There was also not a significant difference in time-to-task-completion with respect to level of trauma team activation (p < 0.2229). [HR = 1.3 (95% CI: 0.8, 2.1)]. CONCLUSION: While closed-loop communication prevents medical errors, our study highlights the potential to increase the speed and efficiency with which tasks are completed in the setting of pediatric trauma resuscitation. Trauma drills and systems of communication that emphasize the use of closed-loop communication should be incorporated into the training of trauma team leaders. LEVEL OF EVIDENCE: This is a prospective observational study with intervention level II evidence.

Treatment Failure after Multiple Courses of Triclabendazole among Patients with Fascioliasis in Cusco, Peru: A Case Series.

Triclabendazole is reported to be highly effective in treatment of human fascioliasis. We present 7 of 19 selected cases of human fascioliasis referred to our center in the Cusco region of Peru that failed to respond to triclabendazole. These were mostly symptomatic adults of both sexes that continued passing Fasciola eggs in the stool despite multiple treatments with 2 doses of triclabendazole at 10 mg/kg per dose. We documented the presence of eggs by rapid sedimentation and Kato Katz tests after each treatment course. We found that repeated triclabendazole courses were not effective against fascioliasis in this group of people. These findings suggest that resistance to triclabendazole may be an emerging problem in the Andes.

Reporte de caso de enfermedad de Pott en vértebras torácicas altas en un niño de dos años / Pott's Disease in Upper Thoracic Vertebrae in a Two-Year-Old Boy: Case Report

RESUMEN La enfermedad de Pott es un problema de salud en países en desarrollo y su diagnóstico en niños es un desafío. Presentamos el caso de un niño de dos años de edad, con enfermedad de Pott que compromete vértebras torácicas de T1 a T3. El cuadro clínico se caracterizó por dificultad para caminar, fiebre, tos y disnea. Al examen físico, se evidenció cifosis y prominencia ósea en la región cervicodorsal. Se obtuvo una prueba de tuberculina positiva y se aisló Mycobacterium tuberculosis en el cultivo del aspirado gástrico. La resonancia de columna vertebral mostró un absceso frio, destrucción de dos vértebras y compresión de la médula espinal. El paciente presentó mejoría con la terapia antituberculosa. Resaltamos la importancia de tener en cuenta la sospecha clínica para la detección temprana de esta condición, así como un inicio rápido del tratamiento antituberculoso, para evitar la discapacidad y mortalidad asociada a esta enfermedad.

ABSTRACT Pott's disease is a health problem in developing countries and its diagnosis in children is a challenge. Here we present the case of a two-year-old boy with Pott's disease involving T1 to T3 thoracic vertebrae. The clinical presentation was characterized by difficulty walking, fever, cough, and dyspnea. At physical examination, kyphosis and bony prominence were observed in the cervicodorsal area. A positive tuberculin test was obtained, and Mycobacterium tuberculosis was isolated via culture of the gastric aspiration sample. The spine MRI showed a chronic abscess, destruction of two vertebrae, and bone marrow compression. The patient experienced some improvement with anti-TB therapy. Here, we emphasize the importance of giving consideration to the clinical suspicion for the early detection of this condition, as well as a quick TB-treatment start so as to avoid the disability and mortality associated to this disease.

Microfiltración marginal de carillas oclusales de cerómero con diferentes terminaciones. Un estudio in vitro / Marginal microleakage ossclusal ceromer veneers with different finish lines. An in vitro study

Objetivo: Comparar la microfiltración marginal de carillas oclusales de cerómero con diferentes terminaciones: hombro, chámfer y un grupo control sin preparación. Materiales y métodos: Se utilizaron 33 dientes premolares humanos, sanos, extraídos por indicación de ortodoncia. Se dividieron en tres grupos de once por aleatorización. Una vez cementadas las carillas oclusales, las muestras fueron sometidas a un termociclado manual de 1000 ciclos, con el fin de simular el ambiente de la cavidad bucal. Después, fueron puestas en inmersión pasiva con azul de metileno al 2% por un periodo de 24 horas. Una vez culminado el tiempo, se procedió al corte de las muestras a nivel del surco central de cada pieza, con el fin de observar la microfiltración alcanzada. La microfiltración se observó con un microscopio óptico estereoscópico con aumento de lupa de 10x y se calificó según la penetración del colorante y la escala de Cassin y Pearsons modificada. Resultados: La terminación que obtuvo la mayor microfiltración fue la de hombro, con un 45% de filtración en pared axial (escala 4). El grupo con la menor filtración fue sin línea de terminación, en la cual el 72,7% se ubicó en la escala 1. La prueba de asociación de Chi cuadrado fue significativa y se obtuvo un resultado de p < 0,001. Conclusión: Existe asociación entre el aumento de microfiltración y la línea de terminación tipo hombro. Esta relación debe tenerse en cuenta al momento de la planificación de tratamiento protésico. (AU)

Objective: To compare the marginal microleakage of occlusal ceromer veneers with different finish lines; shoulder, chamfer and a group without preparation. Materials and methods:33 sound human premolars under orthodontic extraction were used. They were divided into 3 groups of 11 each. Once the occlusal veneers were bonded, they were manually thermocycled for 1000 cycles with the aim of simulating the oral cavity. They were then immersed in 2% blue methylene for 24 hours, after which cross section samples of the central groove were taken for micro-leakage observation. The microleakage was observed with an optical stereos-copic microscope with 10x magnification power and classified according to the Cassin and Pearson's modified scale. Results: The finish line with the most microleakage was the shoulder, with 45% of axial wall microleakage (scale 4). The least microleakage was observed in the group without finish line, with 72.7% (scale 1). Conclusion: The association between greater microleakage and the shoulder finish line was determined. (AU)