The purinergic signalling and inflammation in the pathogenesis and progression of diabetes: key factors and therapeutic targets.

Type 2 diabetes mellitus (T2DM) is an important chronic disease around the world, and according to the World Health Organization, it is the 9th principal cause of global death. This pathology is characterized by high levels of circulating glucose as a result of insulin resistance, and it is well stated that inflammation related to obesity is directly associated with the development of the disease. The purinergic signalling is involved in both pancreatic destruction, which impairs insulin secretion, and the cytokine production that favors insulin resistance in T2DM. In this review, the purinergic signalling aspects will be discussed, showing the impact of the enzymes, nucleotides, nucleosides, and receptors of this system and the cytokines that result in inflammation, in the development and progression of T2DM, besides, pointing the purinergic receptors as a possible therapeutic approach.

Inhibition of bacterial growth through LED (light-emitting diode) 465 and 630 nm: in vitro.

Photobiomodulation has been used to inactivate bacterial growth, in different laser or LED protocols. Thus, the aim of this study was to verify the inhibition of Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli, in ATCC strains and bacteria collected from patients with skin burns, after irradiation with LED; 300 µl of saline solution with bacterial suspension was irradiated at a concentration of 0.5-0.63, by the McFarland scale, after five serial dilutions, with evaluation of pre- and post-irradiation pH and temperature control. The cultures were placed in a bacteriological incubator at 37 °C for 24 h for later counting of colony-forming units (CFU). Data were analyzed by Shapiro-Wilk tests and single-factor ANOVA, with Tukey post hoc (p < 0.05). Both wavelengths and energy densities tested showed inhibition of bacterial growth. The comparison of the irradiated groups (ATCC) with the control group showed the following: S. aureus and P. aeruginosa 465 nm (40 J/cm2) and 630 nm (50 J/cm2) and E. coli 465 nm (40 J/cm2) and 630 nm (30 J/cm2). Among the ATCC S. aureus groups, there was a difference for 630 nm (30 J/cm2) and 465 nm (30, 40, 50 J/cm2). The bacteria from the burned patients were S. aureus (30 and 50 J/cm2) and P. aeruginosa (50 J/cm2). We conclude that different bacterial strains were reduced into colony-forming units after LED irradiation.

Osseous morphology of the medial epicondyle: an anatomoradiological study with potential clinical implications.

PURPOSE: The cubital tunnel is limited anteriorly by the medial epicondyle (ME), laterally by the medial collateral ligament, and superiorly by Osborne's fascia and the cubital tunnel retinaculum. Previous studies were mostly dedicated to the roof of the cubital tunnel, in the way that the study of the groove for ulnar nerve and ME anatomy is relatively scarce in the literature. We sought to describe the radiological anatomy of the groove for ulnar nerve and ME in healthy volunteers with multiplanar computed tomography (CT). METHODS: We analyzed 3D CT images of 30 healthy volunteers (mean age 39 years, range 18-66 years). Nine variables were measured from the right elbow, including sizes, areas and angles in two different planes (coronal and axial). RESULTS: Mean ME width and length were 17.3 ± 3.5 mm and 31.7 ± 4.5 mm, respectively. According to categorical correlation studies, ME width (X) was deemed the most representative morphological characteristic because of the positive correlation to five other different anatomical measurements. A three-tiered anatomical classification was proposed based on data distribution. CONCLUSION: Large individual variation is found in the shape of ME, both in coronal and axial planes. The knowledge of individual osseous morphology is of great value potentially contributing to the surgical decision-making in patients affected by cubital tunnel syndrome.

Factor copula models for right-censored clustered survival data.

In this article we extend the factor copula model to deal with right-censored event time data grouped in clusters. The new methodology allows for clusters to have variable sizes ranging from small to large and intracluster dependence to be flexibly modeled by any parametric family of bivariate copulas, thus encompassing a wide range of dependence structures. Incorporation of covariates (possibly time dependent) in the margins is also supported. Three estimation procedures are proposed: both one- and two-stage parametric and a two-stage semiparametric method where marginal survival functions are estimated by using a Cox proportional hazards model. We prove that the estimators are consistent and asymptotically normally distributed, and assess their finite sample behavior with simulation studies. Furthermore, we illustrate the proposed methods on a data set containing the time to first insemination after calving in dairy cattle clustered in herds of different sizes.

Assessment of body composition by whole-body densitometry: what radiologists should know.

The analysis of body composition is a fundamental part of a nutritional status assessment, and the use of diagnostic imaging methods has been increasingly required for an adequate characterization of the lean body mass and fat mass. Body composition measurements are useful in evaluating the effectiveness of nutritional interventions and monitoring changes associated with aging and chronic diseases. Whole-body densitometry using dual-energy X-ray absorptiometry (DEXA) is one of the most widely used methods in clinical practice, allowing highly accurate assessment of the bone mineral content, lean body mass, and fat mass. Although a DEXA examination provides a lot of information, there is still no universal standardization of the parameters to be included in radiology reports. The aim of this study was to review the most relevant information for assessing body composition by whole-body densitometry.

A análise da composição corporal é parte fundamental de uma avaliação nutricional, em que a utilização de métodos diagnósticos por imagem tem sido cada vez mais requisitada para uma adequada caracterização da massa magra e massa gorda corporal. Medidas de composição corporal são úteis em avaliar a eficácia das intervenções nutricionais e monitorar as mudanças associadas ao envelhecimento e condições de doenças crônicas. A densitometria de corpo inteiro utilizando a técnica de absorciometria de dupla energia (DEXA) é um dos métodos mais utilizados na prática clínica, que permite avaliação com elevada acurácia do conteúdo mineral ósseo, da gordura corporal e da massa magra. Este exame fornece grande quantidade de informações, no entanto, ainda não existe uma padronização universal de quais parâmetros devem ser incluídos nos relatórios radiológicos. O objetivo deste trabalho é revisar as informações mais relevantes para avaliação da composição corporal fornecidas pela densitometria de corpo inteiro.

Evaluation of the Maxillary Sinus of Patients with Maxillary Posterior Implants: A CBCT Cross-Sectional Study.

BACKGROUND: During oral rehabilitation, dental implants in the posterior maxilla can penetrate the maxillary sinus. The aim was to evaluate the presence of maxillary sinus abnormalities in patients with dental implants in the posterior maxillary region using cone-beam computed tomography (CBCT) images. MATERIALS AND METHODS: This was a retrospective cross-sectional study, and CBCT scans of 199 patients (459 dental implants) were evaluated. Implants were assessed according to their relative location to the maxillary sinus floor (up to 2 mm from the maxillary sinus cortex, within 2 mm to intimate contact with the maxillary sinus cortex, apical third inside the maxillary sinus, two-thirds or more inside the maxillary sinus) and bone-fixation tissue (Alveolar ridge or Bone graft). Maxillary sinus abnormalities were classified. Kappa and Weighted Kappa and the Kruskal-Wallis test were applied. RESULTS: A higher prevalence of mucosal thickening and non-specific opacification were observed in implants located within 2 mm to intimate contact with the cortex of the maxillary sinus floor. Of the 66 implants with apical thirds located inside the maxillary sinus, 31 (46.7%) were associated with sinus abnormalities and of all implants (n = 5) with two-thirds or more located inside the maxillary sinus, all of these were associated with sinus abnormalities. No association was observed in relation to implant bone-fixation tissue. CONCLUSIONS: This study found a significant association between dental implant placement near or within the sinus and sinus abnormalities, mainly mucosal thickening and non-specific opacification.

Pharmacokinetic and Pharmacodynamic Characteristics of Vancomycin and Meropenem in Critically Ill Patients Receiving Sustained Low-efficiency Dialysis.

PURPOSE: Antibiotic dosing is challenge in critically ill patients undergoing renal replacement therapy. Our aim was to evaluate the pharmacokinetic and pharmacodynamic (PK/PD) characteristics of meropenem and vancomycin in patients undergoing SLED. METHODS: Consecutive ICU patients undergoing SLED and receiving meropenem and/or vancomycin were prospectively evaluated. Serial blood samples were collected before, during, and at the end of SLED sessions. Antimicrobial concentrations were determined using a validated HPLC method. Noncompartmental PK analysis was performed. AUC was determined for vancomycin. For meropenem, time above MIC was calculated. FINDINGS: A total of 24 patients receiving vancomycin and 21 receiving meropenem were included; 170 plasma samples were obtained. Median serum vancomycin and meropenem concentrations before SLED were 24.5 and 28.0 µg/mL, respectively; after SLED, 14 and 6 µg/mL. Mean removal was 42% with vancomycin and 78% with meropenem. With vancomycin, 19 (83%), 16 (70%), and 15 (65%) patients would have achieved the target (AUC0-24 >400) considering MICs of 1, 2, and 4 mg/L, respectively. With meropenem, 17 (85%), 14 (70%), and 10 (50%) patients would have achieved the target (100% of time above MIC) if infected with isolates with MICs of 1, 4, and 8 mg/L, respectively. IMPLICATIONS: SLED clearances of meropenem and vancomycin were 3-fold higher than the clearance described by continuous methods. Despite this finding, overall high PK/PD target attainments were obtained, except for at higher MICs. We suggest a maintenance dose of 1 g TID or BID of meropenem. With vancomycin, a more individualized approach using therapeutic drug monitoring should be used, as commercial assays are available.

Does ascitic fluid filtration improve the microbiological diagnosis of spontaneous bacterial peritonitis? An experimental laboratory study / A filtração do líquido ascítico melhora o diagnóstico microbiológico da peritonite bacteriana espontânea? Um estudo experimental laboratorial

Background: Spontaneous Bacterial Peritonitis (SBP) is a serious and frequent complication among cirrhotic patients with ascites and can be diagnosed by cytological analysis of the ascitic fluid. The microbiological culture of ascitic fluid, however, is positive in less than 40% of SBP cases, which often results in inappropriate antimicrobial therapy. Empirical therapy may be suboptimal, increasing patient's risk of aggravation, or overestimated, unnecessarily boosting bacterial resistance. Objective: This experimental laboratory study aimed to standardize and verify the technical feasibility of ascitic fluid vacuum filtration, as a way to optimize the etiological diagnosis of SBP, compared to the automated method. Method: The method evaluated and standardized in this study was ascitic fluid vacuum filtration. Its principle is the concentration of bacteria on a filter membrane. Results: This study included 36 cirrhotic patients treated at a public university hospital between 11.13.2017 and 06.30.2019. Among them, 47.2% (17/36) presented cytology test results compatible with SBP. For these patients, culture sensitivity using the automated method was 35.3% (6/17), against 11.8% (2/17) with the vacuum filtration method. Conclusion: In conclusion, vacuum filtration does not improve the microbiological diagnosis of SBP in this population compared to the automated method (AU)

Contexto: A Peritonite Bacteriana Espontânea (PBE) é uma complicação grave e frequente entre pacientes cirróticos com ascite, diagnosticada por meio da análise citológica do líquido ascítico. A cultura microbiológica do líquido ascítico, por sua vez, é positiva em menos de 40% dos casos de PBE, o que resulta frequentemente na instituição de terapia antimicrobiana inapropriada. A terapia empírica pode ser subótima, aumentando o risco de agravamento do paciente, ou superestimada, impulsionando desnecessariamente a resistência bacteriana. Objetivo: Estudo experimental laboratorial, propôs padronizar e verificar a viabilidade técnica da filtração a vácuo do líquido ascítico, como forma de otimizar o diagnóstico etiológico na PBE, comparativamente ao sistema automatizado de culturas de sangue. Método: O método avaliado e padronizado neste estudo foi a da filtragem a vácuo do líquido ascítico. Esse tem como princípio a concentração da bactéria em uma membrana filtrante. Resultados: Nesse estudo, foram incluídos 36 pacientes cirróticos atendidos em um hospital público universitário, entre 13.11.2017 e 30.06.2019. Entre eles, 47,2% (17/36) apresentaram citologia compatível com PBE. Nesses, a sensibilidade da cultura pelo método semi-automatizado foi de 35,3% (6/17) e da cultura pelo método da filtragem a vácuo foi de 11,8% (2/17). Conclusão: Em conclusão, a filtragem a vácuo não melhora o diagnóstico microbiológico da PBE em relação ao método automatizado (AU)

Does ascitic fluid filtration improve the microbiological diagnosis of spontaneous bacterial peritonitis? An experimental laboratory study / A filtração do líquido ascítico melhora o diagnóstico microbiológico da peritonite bacteriana espontânea? Um estudo experimental laboratoria

ABSTRAC: Background: Spontaneous Bacterial Peritonitis (SBP) is a serious and frequent complication among cirrhotic patients with ascites and can be diagnosed by cytological analysis of the ascitic fluid. The microbiological culture of ascitic fluid, however, is positive in less than 40% of SBP cases, which often results in inappropriate antimicrobial therapy. Empirical therapy may be suboptimal, increasing patient's risk of aggravation, or overestimated, unnecessarily boosting bacterial resistance. Objective: This experimental laboratory study aimed to standardize and verify the technical feasibility of ascitic fluid vacuum filtration, as a way to optimize the etiological diagnosis of SBP, compared to the automated method. Method: The method evaluated and standardized in this study was ascitic fluid vacuum filtration. Its principle is the concentration of bacteria on a filter membrane. Results: This study included 36 cirrhotic patients treated at a public university hospital between 11.13.2017 and 06.30.2019. Among them, 47.2% (17/36) presented cytology test results compatible with SBP. For these patients, culture sensitivity using the automated method was 35.3% (6/17), against 11.8% (2/17) with the vacuum filtration method. Conclusion: In conclusion, vacuum filtration does not improve the microbiological diagnosis of SBP in this population compared to the automated method. (AU)

RESUMO:Contexto: A Peritonite Bacteriana Espontânea (PBE) é uma complicação grave e frequente entre pacientes cirróticos com ascite, diagnosticada por meio da análise citológica do líquido ascítico. A cultura microbiológica do líquido ascítico, por sua vez, é positiva em menos de 40% dos casos de PBE, o que resulta frequentemente na instituição de terapia antimicrobiana inapropriada. A terapia empírica pode ser subótima, aumentando o risco de agravamento do paciente, ou superestimada, impulsionando desnecessariamente a resistência bacteriana. Objetivo: Estudo experimental laboratorial, propôs padronizar e verificar a viabilidade técnica da filtração a vácuo do líquido ascítico, como forma de otimizar o diagnóstico etiológico na PBE, comparativamente ao sistema automatizado de culturas de sangue. Método: O método avaliado e padronizado neste estudo foi a da filtragem a vácuo do líquido ascítico. Esse tem como princípio a concentração da bactéria em uma membrana filtrante. Resultados: Nesse estudo, foram incluídos 36 pacientes cirróticos atendidos em um hospital público universitário, entre 13.11.2017 e 30.06.2019. Entre eles, 47,2% (17/36) apresentaram citologia compatível com PBE. Nesses, a sensibilidade da cultura pelo método semi-automatizado foi de 35,3% (6/17) e da cultura pelo método da filtragem a vácuo foi de 11,8% (2/17). Conclusão: Em conclusão, a filtragem a vácuo não melhora o diagnóstico microbiológico da PBE em relação ao método automatizado. (AU)

Effects of previous physical training on adriamycin nephropathy and its relationship with endothelial lesions and angiogenesis in the renal cortex.

AIMS: Adriamycin (ADR)-induced nephropathy is one of the most experimental models used in progressive kidney disease. A single dose of this drug induces a progressive and irreversible proteinuria that progresses to focal segmental glomerulosclerosis and tubulointerstitial lesions. Regular physical activity has been considered as a therapeutic intervention in several diseases. This study evaluated the influence of previous physical training in renal damage induced by ADR and the role of endothelial lesions and angiogenesis in this process. MAIN METHODS: Male Wistar rats were subjected or not to treadmill running for 4weeks and then injected with ADR (2.5mg/kg, i.v.) or saline. Twenty-four-hour urine samples were collected for albuminuria measurement, and blood samples were collected to measure plasma creatinine 60days after the injections. The kidneys were removed for histological, immunohistochemical, Western blot and ELISA studies. KEY FINDINGS: ADR-treated rats presented increases in plasma creatinine levels, albuminuria, podocyte damage, and enlargement of the tubular interstitial relative area, as well as higher macrophage numbers in the renal cortex, interleukin (IL)-1ß levels in renal tissue and urinary monocyte chemoattractant protein (MCP)-1, which were associated with reduction in vascular endothelial growth factor (VEGF), endothelial nitric oxide synthase (eNOS) expressions and peritubular capillary (PTC) density in renal cortex. These alterations were less intense in the animals subjected to previous exercise training. SIGNIFICANCE: Physical training prior to ADR injection reduced the renal damage induced by this drug. This effect was related to angiogenesis and reduction in the endothelial lesions and inflammatory process in the renal cortex of these animals.

Assessment of body composition by whole-body densitometry: what radiologists should know / Avaliação da composição corporal pela densitometria de corpo inteiro: o que os radiologistas precisam saber

Abstract The analysis of body composition is a fundamental part of a nutritional status assessment, and the use of diagnostic imaging methods has been increasingly required for an adequate characterization of the lean body mass and fat mass. Body composition measurements are useful in evaluating the effectiveness of nutritional interventions and monitoring changes associated with aging and chronic diseases. Whole-body densitometry using dual-energy X-ray absorptiometry (DEXA) is one of the most widely used methods in clinical practice, allowing highly accurate assessment of the bone mineral content, lean body mass, and fat mass. Although a DEXA examination provides a lot of information, there is still no universal standardization of the parameters to be included in radiology reports. The aim of this study was to review the most relevant information for assessing body composition by whole-body densitometry.

Resumo A análise da composição corporal é parte fundamental de uma avaliação nutricional, em que a utilização de métodos diagnósticos por imagem tem sido cada vez mais requisitada para uma adequada caracterização da massa magra e massa gorda corporal. Medidas de composição corporal são úteis em avaliar a eficácia das intervenções nutricionais e monitorar as mudanças associadas ao envelhecimento e condições de doenças crônicas. A densitometria de corpo inteiro utilizando a técnica de absorciometria de dupla energia (DEXA) é um dos métodos mais utilizados na prática clínica, que permite avaliação com elevada acurácia do conteúdo mineral ósseo, da gordura corporal e da massa magra. Este exame fornece grande quantidade de informações, no entanto, ainda não existe uma padronização universal de quais parâmetros devem ser incluídos nos relatórios radiológicos. O objetivo deste trabalho é revisar as informações mais relevantes para avaliação da composição corporal fornecidas pela densitometria de corpo inteiro.

High mortality of bloodstream infection outbreak caused by carbapenem-resistant P. aeruginosa producing SPM-1 in a bone marrow transplant unit.

PURPOSE: Carbapenem resistance in P. aeruginosa is increasing worldwide. In Brazil, SPM-1 is the main P. aeruginosa carbapenemase identified. Little is known about the virulence factor in SPM-1 clones.Methodolgy. We describe a carbapenem-resistant P. aeruginosa bloodstream infection (CRPa-BSI) outbreak in a bone marrow transplant Unit (BMT). Twenty-nine CRPa-BSI cases were compared to 58 controls. Microbiological characteristics of isolates, such as sensitivity, carbapenemase gene PCR for P. aeruginosa, and PFGE are described, as well as the whole-genome sequence (WGS) of three strains.Results/Key findings. The cultures from environmental and healthcare workers were negative. Some isolates harboured KPC and SPM. The WGS showed that the 03 strains belonged to ST277, presented the same mutations in outer membrane protein, efflux pump, and virulence genes such as those involved in adhesion, biofilm, quorum-sensing and the type III secretion system, but differ regarding the carbapenemase profile. A predominant clone-producing SPM harbouring Tn 4371 was identified and showed cross-transmission; no common source was found. Overall mortality rate among cases was 79 %. The first multivariate analysis model showed that neutropenia (P=0.018), GVHD prophylaxis (P=0.016) and prior use of carbapenems (P=0.0089) were associated with CRPa-BSI. However, when MASCC>21 points and platelets were added in the final multivariate analysis, only prior use of carbapenems remained as an independent risk factor for CRPa-BSI (P=0.043). CONCLUSIONS: The predominant clone belonging to ST277 showed high mortality. Carbapenem use was the only risk factor associated with CRPa-BSI. This finding is a wake-up call for the need to improve management in BMT units.

Thermocoagulation as a Surgical Approach for the Treatment of Obsessive-Compulsive Disorder in Refractory Patients: Systematic Review

Obsessive-compulsive disorder (OCD), a disabling chronic neuropsychiatric disease, entails high economic costs to society and has high morbidity and mortality rates. The first-line treatments for OCD are selective serotonin reuptake inhibitors and cognitivebehavioral therapy. However, this disorder has the highest refractory index to noninvasive treatment. Alternatively, ablative thermocoagulation neurosurgical techniques have shown efficacy and few adverse effects. The present systematic review aimed to identify validated protocols to observe the effectiveness of ablative procedures in the treatment of severe and refractory OCD, as well as their possible adverse effects and benefits. This review supports the effectiveness of ablative methods by presenting them as a safe non-experimental therapeutic option for cases of highlyrefractory OCD. Additional relevant findings were the improvement in cognitive function, functional capacity, affective orientation, and quality of life, which contribute to the destigmatization of this surgical technique. Further controlled studies may lead to the individualization of recommendations of targets for ablative thermocoagulation.

Externally studentized normal midrange distribution / Distribuição da midrange estudentizada externamente

ABSTRACT The distribution of externally studentized midrange was created based on the original studentization procedures of Student and was inspired in the distribution of the externally studentized range. The large use of the externally studentized range in multiple comparisons was also a motivation for developing this new distribution. This work aimed to derive analytic equations to distribution of the externally studentized midrange, obtaining the cumulative distribution, probability density and quantile functions and generating random values. This is a new distribution that the authors could not find any report in the literature. A second objective was to build an R package for obtaining numerically the probability density, cumulative distribution and quantile functions and make it available to the scientific community. The algorithms were proposed and implemented using Gauss-Legendre quadrature and the Newton-Raphson method in R software, resulting in the SMR package, available for download in the CRAN site. The implemented routines showed high accuracy proved by using Monte Carlo simulations and by comparing results with different number of quadrature points. Regarding to the precision to obtain the quantiles for cases where the degrees of freedom are close to 1 and the percentiles are close to 100%, it is recommended to use more than 64 quadrature points.

RESUMO A distribuição da midrange estudentizada externamente foi criada com base nos procedimentos de estudentização de Student e foi inspirada na distribuição da amplitude estudentizada externamente. O amplo uso da amplitude estudentizada externamente em comparações múltiplas também foi uma das motivações para desenvolver esta nova distribuição. Neste trabalho objetivou-se derivar expressões analíticas da distribuição da midrange estudentizada externamente, obtendo a função de distribuição, função densidade de probabilidade, função quantil e geradores de números aleatórios. Essa é uma nova distribuição que os não há relatos na literatura especializada. Um segundo objetivo foi construir um pacote R para obter numericamente as funções mencionadas e torná-las disponíveis para a comunidade científica. Os algoritmos foram propostos e implementados usando os métodos de quadratura Gauss-Legendre e Newton-Raphson no software R, resultando no pacote SMR, disponível para baixar na página do CRAN. As rotinas implementadas apresentaram alta acurácia, sendo verificadas usando simulação Monte Carlo e pela comparação com diferentes pontos de quadratura. Quanto a precisão para se obter os quantis da distribuição da midrange estudentizada externamente para 1 grau de liberdade ou percentis próximo de 100%, é sugerido utilizar mais do que 64 pontos de quadratura.

Ajuste de modelos de platô de resposta via regressão isotônica / Response plateau models fitting via isotonic regression

Dentro do contexto nutricional, a suplementação de microminerais em rações para aves frequentemente é feita em quantidades superiores às exigidas na tentativa de assegurar o bom desempenho dos animais. Os experimentos do tipo dose resposta são muito comuns na determinação de níveis ótimos dos nutrientes na ração e contemplam a utilização de modelos de regressão para atingir tal objetivo. Porém, na análise de regressão usual, geralmente, não se usa uma informação a priori sobre uma possível relação de ordem na variável resposta. A regressão isotônica é um método de estimação por mínimos quadrados que gera estimativas que satisfazem a mesma ordenação dos dados. Na teoria da regressão isotônica, essa informação é utilizada de forma essencial e espera-se que a eficiência do ajuste seja aumentada quando se faz uso dela. Diante do exposto, o presente trabalho tem como objetivo utilizar uma metodologia de regressão isotônica, como uma forma alternativa para analisar dados de deposição de zinco (Zn) na tíbia de aves machos da linhagem Hubbard. No estudo, foram considerados os modelos de platô de resposta polinomial quadrático e não linear exponencial. Além desses modelos, também foi proposto o ajuste de um modelo logarítmico para os dados e a eficiência da metodologia foi avaliada por meio de um estudo de simulação Monte Carlo, considerando diferentes cenários para os valores paramétricos. A isotonização dos dados propiciou uma melhora em todos os avaliadores de qualidade de ajuste considerados no trabalho. Dentre os modelos utilizados, o logarítmico apresentou estimativas dos parâmetros mais coerentes com os valores relatados na literatura, para os dados de deposição de Zn na tíbia de aves machos.

Within the nutritional context, the supplementation of microminerals in bird food is often made in quantities exceeding those required in the attempt to ensure the proper performance of the animals. The experiments of type dosage x response are very common in the determination of levels of nutrients in optimal food balance and include the use of regression models to achieve this objective. Nevertheless, the regression analysis routine, generally, uses a priori information about a possible relationship between the response variable. The isotonic regression is a method of estimation by least squares that generates estimates which preserves data ordering. In the theory of isotonic regression this information is essential and it is expected to increase fitting efficiency. The objective of this work was to use an isotonic regression methodology, as an alternative way of analyzing data of Zn deposition in tibia of male birds of Hubbard lineage. We considered the models of plateau response of polynomial quadratic and linear exponential forms. In addition to these models, we also proposed the fitting of a logarithmic model to the data and the efficiency of the methodology was evaluated by Monte Carlo simulations, considering different scenarios for the parametric values. The isotonization of the data yielded an improvement in all the fitting quality parameters evaluated. Among the models used, the logarithmic presented estimates of the parameters more consistent with the values reported in literature.