Specificity and Sensitivity of Screening for Anti-HLA Antibodies in Kidney Allograft Dysfunction

BACKGROUND: Prospective testing for posttransplant circulating anti-HLA antibodies seems to be a critical noninvasive tool, but confirmatory data are lacking. MATERIALS AND METHODS: Over the last 3 years, peritubular capillary (PTC) C4d deposition was prospectively sought by an immunofluorescence technique applied to frozen tissue in biopsies obtained for allograft dysfunction. Screening for circulating anti-HLA class I/II alloantibodies (AlloAb) by the flow cytometric test was performed simultaneously. RESULTS: We evaluated 132 sets of biopsies and simultaneous serum samples. PTC C4d deposition was demonstrated in 15.9% (21/132) of biopsies. Circulating anti-HLA I/II AlloAb were detected in 25% (33/132) of serum samples. Employing receiver-operator characteristic (ROC) curves for all C4d-positive biopsies, screening for AlloAb showed a global specificity of 82% and sensitivity of 61.9%. When this analysis was restricted to biopsies obtained in the first month posttransplantation, the sensitivity increased to 81.8%, but the specificity decreased to 76.9%. After the first month posttransplantation, we observed sensitivity of 40.0% and a specificity of 86.4%. In the first month posttransplantation, all patients with a diagnosis of acute antibody-mediated rejection displayed circulating anti-HLA class I/II, but not always at the same time as the C4d-positive biopsy. CONCLUSIONS: In the first month posttransplantation, prospective monitoring of anti-HLA antibodies may be useful. The high sensitivity allows the identification of patients at risk, affording an earlier diagnosis of antibody-mediated rejection. After the first month, the test can be used to evaluate allograft dysfunction episodes, since positivity is highly suggestive of an antibody-mediated process.

C4d Presence in Kidney Allograft Biopsy: Sensitivity and Specifity of Immunoperoxidase vs Immunofluorescence

OBJECTIVES: Evaluate the sensitivity/specificity of immunoperoxidase method in comparison with the standard immunofluorescence. MATERIAL AND METHODS: Retrospective review of 87 biopsies made for allograft dysfunction. Immunofluorescence (IF) was performed in frozen allograft biopsies using monoclonal antibody anti-C4d from Quidel®. The indirect immunoperoxidase (IP) technique was performed in paraffin-embebbed tissue with polyclonal antiserum from Serotec®. Biopsies were independently evaluated by two nephropathologist according Banff 2007 classification. RESULTS: By IF, peritubular C4d deposition were detected in 60 biopsies and absent in 27 biopsies. The evaluation of biopsy by IP was less precise due to the presence of background and unspecific staining. We find 13.8% (12/87) of false negative and Banff classification concordance in 79.3% (69/87) of cases (table1). The ROC curve study reveal a specificity of 100% and sensitivity of 80.0 % of IP method in relation to the gold standard (area under curve:0.900; 95% Confidence interval :0.817-0.954; p=0.0001). Banff Classification C4d Cases Immunofluorescence Immunoperoxidase n =87 Diffuse Negative 3 (3.4%) Focal Negative 9 (10.3%) Negative Negative 27 (31.0%) Diffuse Diffuse 33 (37.9%) Focal Focal 9 (10.3%) Diffuse Focal 6 (6.9%) CONCLUSION: The IP method presents a good specificity, but lesser sensitivity to C4d detection in allograft dysfunction. The evaluation is more difficult, requiring more experience of the observer than IF method. If frozen tissue is unavailable, the use of IP for C4d detection is acceptable.

Sensitivity of Gomez-Nuñez boxes for the detection of household infestation with Panstrongylus megistus

Four methods for detecting household infestations with Panstrongylus megistus were compared: 1) manual collection; 2) collection after pyrethrum application; 3) search viable eggs; and 4) Gomez-Nuñez boxes. Manual collection was the most sensitive method (23% infested), followed by pyrethrum (21%), Gomez-Nuñez boxes (15%) and viable eggs (12%). About 10% of infested houses were positive exclusively on the Gomez-Nuñez box test. More over, 6 out of the 7 houses positive exclusively on the Gomez-Nuñez method were located in a recently sprayed area, where P. megistus density was low. Inspection of Gomez-Nuñez boxes at 12 weekspost-application was twice as effective as inspection at 6 weekspost-application. Triatomine feces was the most common evidencefor thepresence of P. megistus found within Gomez-Nuñez boxes. Gomez-Nuñez boxes area a useful adjunct to manual collection in detecting domestic infestations with P. megistus, especially in areas where bug densities are low. However, the utility of Gomez-Nuhez boxes must be weighed against the time and labor they require.

Increased osmotic sensitivity for antidiuretic response in chronic chagas' disease

The osmotic threshold for attaining the antidiuretic response to hypertonic saline infusion and Progressive dehydration was studied in 31 patients with the chronic form of Chagas' disease and 16 control patients. The chagasic patients exhibited enhanced osmoticsensitivity to the antidiuretic response. This was demonstrated by lower values of the increments in plasma osmolarity sufficient to induce a significant fall in water clearance, without alterations in the osmolar clearance or creatinine excretion. The time needed to attain the antidiuretic response was shorterfor chagasics in relation to normal subjects. The results suggest the existence of a disturbance in the fine control of osmoregulation in the chagasic patients. They are interpreted to be a consequence of the denervation in hypothalamic or extrahypothalamic areas that regulate the secretion of vasopressin in chronic Chagas' disease.

Sensitivity correction of images obtained with the prototype Clear-PEM in pre-clinical environment

Dissertation presented at Faculdade de Ciências e Tecnologia Universidade Nova de Lisboa to obtain a Master Degree in Biomedical Engineering

Low sensitivity of polymerase chain reaction for diagnosis of tuberculous meningitis in southeastern Brazil

Two polymerase chain reaction (PCR) protocols showed low sensitivity (36% and 53% for TB AMPLICOR and MPB64 nested PCR, respectively), when compared with classic microbiological methods (73% and 54% for Ziehl-Neelsen staining and culture, respectively), in the diagnosis of tuberculous meningitis in 91 patients in southeastern Brazil. Only three PCR-positive, microbiologically negative patients were found. Analysis of sequential cerebrospinal fluid samples by nested PCR detected Mycobacterium tuberculosis DNA up to 29 days after the introduction of antituberculosis chemotherapy.

Sensitivity of polymerase chain reaction for detection of known aliquots of Trypanosoma cruzi in the blood of mice: an in vitro study

To evaluate the sensitivity of polymerase chain reaction (PCR) to reveal known number of trypomastigote in the blood of mice, three separate experiments were done. First: To eight samples of 500mul of normal mice blood, one aliquot of 1, 2, 3, 4, 5, 10, and 50 trypomastigotes respectively, were added. Second and third: 10 aliquots with 1 and 10 with 2 trypomastigotes were added to samples of 500mul of normal mice blood. Positive control: 500mul of blood containing 100,000 trypomastigotes. For kDNA minicircles amplification by PCR the primers:S35 and S36 were used. PCR revealed products of 330 b.p in the positive controls. When only one sample with the aliquots of 1 or 2 trypomastigotes was examined, results were negative; results were positive with aliquots of 3 to 50 trypomastigotes. In the 2nd and 3rd experiments, 9/10 aliquots with one parasite and 9/10 with 2 trypomastigotes were positive revealing a high sensitivity of this reaction. In conclusion, the presence of one single parasite in 500mul of blood, is enough for a positive PCR. This method could be used as a complement to the various parasitological cure tests in treated mice, when low volumes of blood are individually examined.

Disclosing the caffeine dose to be administered that restores insulin sensitivity in prediabetes animal

The results discussed in this thesis originated the following communications in International and National congresses: Sacramento JF, Coelho JC, Melo BF, Guarino MP and Conde SV. (2014) Assessment of caffeine dose and time of administration required for resetting insulin sensitivity in high sucrose diet in rats. 50th Meeting of EASD (European Association for the study of Diabetes), 14-19 September, Vienna, Austria Coelho JC, Melo BF, Sacramento JF, Guarino MP and Conde SV (2014). Establishing the caffeine dose that chronically restores insulin sensitivity in animal model of prediabetes. Fundação Astrazeneca Innovate Competition, iMed conference 6.0®, 10-12 October, Lisboa, Portugal Also, during the last year I was involved in other ongoing projects that originated the following communications: Coelho JC, Melo BF, Sacramento JF, Ribeiro MJ, Guarino MP and Conde SV (2014). Are the effects of carotid sinus nerve resection on insulin sensitivity mediated by an increase in Glut4 expression in skeletal muscle?. XLIV Reunião Anual da Sociedade Portuguesa de Farmacologia, XXXII Reunião de Farmacologia Clínica e XIII Reunião de Toxicologia, 5-7 February, Coimbra, Portugal Sacramento JF, Rodrigues T, Coelho JC, Matafome P, Ribeiro MJ, Seiça RM, Guarino MP, Conde SV (2014). Elucidating the mechanism by which carotid sinus nerve resection restores insulin sensitivity in pre-diabetes animal models. International Society for Arterial Chemoreception (ISAC) XIX University of Leeds, 29th June - 3rd July, Leeds, United Kingdom

Occurrence and sensitivity profile of extended spectrum beta-lactamase-producing Enterobacteriaceae at a tertiary hospital in Southern Brazil

Abstract: INTRODUCTION: Nosocomial infections are closely associated with antimicrobial drug resistance. One of the most important mechanisms of resistance to β-lactam antibiotics is the production of extended spectrum β-lactamases (ESBLs). The objective of the present study was to evaluate the prevalence and antimicrobial susceptibility profile of ESBL-producing strains and to assess the evolution of antimicrobial drug resistance between 2007 and 2013 at the Hospital São Vicente de Paulo, Passo Fundo, State of Rio Grande do Sul, Brazil. METHODS: We conducted a descriptive, observational, cross-sectional study. Bacterial culture was performed from January to December 2013. The antimicrobial susceptibility profile of these cultures was determined using the disk diffusion method. Phenotypic screening for ESBL production was performed using the disk approximation method. RESULTS : We analyzed a total of 19,112 cultures, 11.5% of which were positive for Enterobacteriaceae. Of these, 30.3% of the isolates were positive for ESBL production, and the most prevalent species was Klebsiella sp. (37.5%). Over 95% of these isolates showed reduced susceptibility to all cephalosporins, aztreonam, and amoxicillin/clavulanic acid. The isolates also showed high sensitivity to the following antimicrobials: amikacin, meropenem, and piperacillin/tazobactam. Overall, the resistance rates among ESBL-producing Enterobacteriaceae decreased from 2007 to 2013. CONCLUSIONS : In our hospital, the increased sensitivity to certain antimicrobial agents seems to be directly related to the implementation of improvements in the methods to prevent and control nosocomial infections in addition to the natural development of other resistance mechanisms.

End-of-day dryness, corneal sensitivity and blink rate in contact lens wearers

Purpose: To study the relationship among the variables intensity ofthe end-of-day (EOD) dryness, corneal sensitivity and blink rate in soft contact lens (CL) wearers. Methods: Thirty-eight soft CL wearers (25 women and 13 men; mean age 27.1 ± 7.2 years) were enrolled. EOD dryness was assessed using a scale of 0–5 (0, none to 5, very intense). Mechanical and thermal (heat and cold) sensitivity were measured using a Belmonte’s gas esthesiometer. The blink rate was recorded using a video camera while subjects were wearing a hydrogel CL and watching a film for 90 min in a controlled environmental chamber. Results: A significant inverse correlation was found between EOD dryness and mechanical sensitivity (r: −0.39; p = 0.02); however, there were no significant correlations between EOD dryness and thermal sensitivity. A significant (r: 0.56; p < 0.001) correlation also was observed between EOD dryness and blink rate, but no correlations were found between blink rate and mechanical or thermal sensitivity. Conclusions: CL wearers with higher corneal sensitivity to mechanical stimulation reported more EOD dryness with habitual CL wear. Moreover, subjects reporting more EOD dryness had an increased blink rates during wear of a standard CL type. The increased blink rate could act to improve the ocular surface environment and relieve symptoms

Sensitivity of the Amazon biome to high resolution climate change projections

ABSTRACT: Despite the reduction in deforestation rate in recent years, the impact of global warming by itself can cause changes in vegetation cover. The objective of this work was to investigate the possible changes on the major Brazilian biome, the Amazon Rainforest, under different climate change scenarios. The dynamic vegetation models may simulate changes in vegetation distribution and the biogeochemical processes due to climate change. Initially, the Inland dynamic vegetation model was forced with initial and boundary conditions provided by CFSR and the Eta regional climate model driven by the historical simulation of HadGEM2-ES. These simulations were validated using the Santarém tower data. In the second part, we assess the impact of a future climate change on the Amazon biome by applying the Inland model forced with regional climate change projections. The projections show that some areas of rainforest in the Amazon region are replaced by deciduous forest type and grassland in RCP4.5 scenario and only by grassland in RCP8.5 scenario at the end of this century. The model indicates a reduction of approximately 9% in the area of tropical forest in RCP4.5 scenario and a further reduction in the RCP8.5 scenario of about 50% in the eastern region of Amazon. Although the increase of CO2 atmospheric concentration may favour the growth of trees, the projections of Eta-HadGEM2-ES show increase of temperature and reduction of rainfall in the Amazon region, which caused the forest degradation in these simulations.

Summary of the ATLAS experiment's sensitivity to supersymmetry after LHC Run 1-interpreted in the phenomenological MSSM

A summary of the constraints from the ATLAS experiment on R-parity-conserving supersymmetry is presented. Results from 22 separate ATLAS searches are considered, each based on analysis of up to 20.3 fb−1 of proton-proton collision data at centre-of-mass energies of s√=7 and 8 TeV at the Large Hadron Collider. The results are interpreted in the context of the 19-parameter phenomenological minimal supersymmetric standard model, in which the lightest supersymmetric particle is a neutralino, taking into account constraints from previous precision electroweak and flavour measurements as well as from dark matter related measurements. The results are presented in terms of constraints on supersymmetric particle masses and are compared to limits from simplified models. The impact of ATLAS searches on parameters such as the dark matter relic density, the couplings of the observed Higgs boson, and the degree of electroweak fine-tuning is also shown. Spectra for surviving supersymmetry model points with low fine-tunings are presented.

Reliability and convergent validity of the Childhood Anxiety Sensitivity Index in children and adolescents

OBJECTIVE: The purpose of this study was to examine the reliability and the convergent validity of the Children Anxiety Sensitivity Index (CASI) with DSM-IV anxiety disorder symptoms, by comparison with the Screen for Child Anxiety Related Emotional Disorders (SCARED), in a community sample of Brazilian children and adolescents. METHODS: Children and adolescents from five schools were selected from a larger study that aimed to assess different aspects of childhood anxiety disorders. All participants completed the CASI and the SCARED. RESULTS: This study supported the reliability of the CASI total score. Girls reported higher total anxiety sensitivity scores than boys and there were no differences in total anxiety sensitivity scores between children and adolescents. This study showed moderate to high correlations between the CASI scores with SCARED scores, all correlations coefficients being positive and significant. CONCLUSIONS: Our findings demonstrate an appropriate reliability and evidence of convergent validity in the CASI in a sample of Brazilian children and adolescents.