Gold nanoparticle to antibody conjugates for diagnosis applications: molecular interactions and immunoassay development

Thesis for the Master degree in Structural and Functional Biochemistry

A retrospective evaluation of a score system adopted by the Ministry of Health, Brazil in the diagnosis of pulmonary tuberculosis in childhood: a case control study

Based on a retrospective case-control study we evaluated the score system adopted by the Ministry of Health of Brazil (Ministério da Saúde - MS), to diagnose pulmonary tuberculosis (PTB) in childhood. This system is independent of bacteriological or histopathological data to define a very likely (> or = 40 points), possible (30-35 points) or unlikely (< or = 25 points) diagnosis of tuberculosis. Records of hospitalized non-infected HIV children at the Instituto de Puericultura e Pediatria Martagão Gesteira of Federal University of Rio de Janeiro (IPPMG-UFRJ), were reviewed. Patients were adjusted for age and divided in two different groups: 45 subjects in the case group (culture-positive) [mean of age = 10.64 mo; SD 9.66]; and 96 in the control group (culture-negative and clinic criteria that dismissed the disease) [mean of age = 11.79 mo.; SD 11.31]. Among the variables analyzed, the radiological status had the greater impact into the diagnosis (OR = 25.39), followed by exposure to adult with tuberculosis (OR = 10.67), tuberculin skin test >10mm (OR = 8.23). The best cut-off point to the diagnosis of PTB was 30 points, where the score system was more accurate, with sensitivity of 88.9% and specificity of 86.5%.

Diagnosis of abdominal angiostrongyliasis by PCR from sera of patients

Abdominal angiostrongyliasis is a zoonotic infection caused by an intra-vascular nematode parasitic of wild rodents, Angiostrongylus costaricensis. No parasitological diagnosis is currently available and immunodiagnosis presents several drawbacks. Primers constructed based on a congeneric species, A. cantonensis, were able to amplify a 232 bp fragment from serum samples of 3 patients with histopathological diagnosis. Extraction was better performed with DNAzol and the specificity of the primers was confirmed by Southern blot. This disease has been diagnosed with frequency in south of Brazil, thus, this method appears like the important and unpublished alternative to improve diagnostic of disease.

Comparison between immunomagnetic separation, coupled with immunofluorescence, and the techniques of Faust et al. and of Lutz for the diagnosis of Giardia lamblia cysts in human feces

In the present study, the performance of Immunomagnetic Separation technique, coupled with Immunofluorescence (IMS-IFA), was compared with the FAUST et al. and Lutz parasitological techniques for the detection of Giardia lamblia cysts in human feces. One hundred and twenty-seven samples were evaluated by the three techniques at the same time showing a rate of cyst detection of 27.5% by IMS-IFA and 15.7% by both Faust et al. and Lutz techniques. Data analysis showed a higher sensitivity of IMS-IFA for the detection of G. lamblia cysts in comparison with the techniques of FAUST et al. and Lutz. The use of this methodology as a routine procedure enables the processing of many samples simultaneously, in order to increase recovery rate of G. lamblia cysts and reduce the time of sample storage.

Condition-Based Diagnosis of Mechatronic Systems Using a Fractional Calculus Approach

While fractional calculus (FC) is as old as integer calculus, its application has been mainly restricted to mathematics. However, many real systems are better described using FC equations than with integer models. FC is a suitable tool for describing systems characterised by their fractal nature, long-term memory and chaotic behaviour. It is a promising methodology for failure analysis and modelling, since the behaviour of a failing system depends on factors that increase the model’s complexity. This paper explores the proficiency of FC in modelling complex behaviour by tuning only a few parameters. This work proposes a novel two-step strategy for diagnosis, first modelling common failure conditions and, second, by comparing these models with real machine signals and using the difference to feed a computational classifier. Our proposal is validated using an electrical motor coupled with a mechanical gear reducer.

An efficient numerical scheme for solving multi-dimensional fractional optimal control problems with a quadratic performance index

The shifted Legendre orthogonal polynomials are used for the numerical solution of a new formulation for the multi-dimensional fractional optimal control problem (M-DFOCP) with a quadratic performance index. The fractional derivatives are described in the Caputo sense. The Lagrange multiplier method for the constrained extremum and the operational matrix of fractional integrals are used together with the help of the properties of the shifted Legendre orthonormal polynomials. The method reduces the M-DFOCP to a simpler problem that consists of solving a system of algebraic equations. For confirming the efficiency and accuracy of the proposed scheme, some test problems are implemented with their approximate solutions.

Skin Prick Tests and Allergy Diagnosis

Skin testing remains an essential diagnostic tool in modern allergy practice. A signifi cant variability has been reported regarding technical procedures, interpretation of results and documentation. This review has the aim of consolidating methodological recommendations through a critical analysis on past and recent data. This will allow a better understanding on skin prick test (SPT) history; technique; (contra-) indications; interpretation of results; diagnostic pitfalls; adverse reactions; and variability factors.

PCR - based diagnosis to evaluate the performance of malaria reference centers

Although the Giemsa-stained thick blood smear (GTS) remains the gold standard for the diagnosis of malaria, molecular methods are more sensitive and specific to detect parasites and can be used at reference centers to evaluate the performance of microscopy. The description of the Plasmodium falciparum, P. vivax, P. malariae and P. ovale ssrRNA gene sequences allowed the development of a polymerase chain reaction (PCR) that had been used to differentiate the four species. The objective of this study was to determine Plasmodium species through PCR in 190 positive smears from patients in order to verify the quality of diagnosis at SUCEN's Malaria Laboratory. Considering only the 131 positive results in both techniques, GTS detected 4.6% of mixed and 3.1% of P. malariae infections whereas PCR identified 19.1% and 13.8%, respectively.

Neurocryptococcosis: diagnosis by PCR method

Cryptococcus neoformans detection was optimized using PCR technique with the objective of application in the clinical laboratory diagnosis. The amplification area was ITS and 5,6S which encodes the ribosomal RNA (rRNA). A total of 72 cerebrospinal fluid (CSF) samples were used, obtained from cases with and without AIDS. The patients had cryptococcal meningitis (n = 56) and meningitis caused by other agents (n = 16). The results demonstrated that PCR test had the highest sensitivity rates, superior to culture (85.7%) and to India ink test (76.8%). PCR was found to be sensitive in detecting 1 cell/mL and highly specific since it did not amplify other fungal DNA. The comparative analysis of the methods showed that PCR is more sensitive and specific and is applicable as an important laboratorial resource for neurocryptococcosis diagnosis.

Coarctação Isolada da Aorta: Experiência em 100 Doentes Consecutivos

INTRODUCTION: Coarctation of the aorta (CoA) is a stenosis usually located in the descending aorta. Treatment consists of surgical or percutaneous removal of the obstruction and presents excellent immediate results but significant residual problems often persist. OBJECTIVES: To describe the presentation, treatment and long-term evolution of a population of 100 unselected consecutive patients with isolated CoA in a single pediatric cardiology center. METHODS: This was a retrospective study of all patients with isolated CoA treated during4 the last 21 years (1987-2008). RESULTS: The patients (n=100, 68.3% male) were diagnosed at a median age of 94 days (1 day to 16 years). The clinical presentation differed between patients aged less or more than one year, the former presenting with heart failure and the latter being asymptomatic with evidence of hypertension (88 and 63%, respectively; p < 0.01). Treatment, a median of 8 days after diagnosis, was surgical in 79 cases (20 end-to-end anastomosis, 31 subclavian flap, 28 patch) and percutaneous in the remaining 21 (15 balloon angioplasty, 6 with stenting). The mean age of surgical patients was younger than in those treated percutaneously (3.4 vs. 7.5 years; p < 0.01). Immediate mortality was 2% and occurred in the surgical group. There was no late mortality, in a mean follow-up of 7.2 +/- 5.4 years. Recoarctation occurred in 8 patients (6 surgical, 2 percutaneous). There are 46 patients who currently have hypertension (19 at rest, 27 with effort), their median age at diagnosis being older than the others (23 vs. 995 days; p < 0.01). CONCLUSIONS: Isolated CoA has an excellent short-term prognosis but a significant incidence of long-term complications, and should thus no longer be seen as a simple obstruction in the descending aorta, but rather as a complex pathology that requires careful follow-up after treatment. Its potentially insidious presentation requires a high level of clinical suspicion, femoral pulse palpation during physical examination of newborns and older children being particularly important. Delay in treatment has an impact on late morbidity and mortality. Taking into account the data currently available on late and immediate results, the final choice of therapeutic technique depends on the patient's age, associated lesions and the experience of the medical-surgical team. Hypertension should be closely monitored in the follow-up of these patients, as well as its risk factors and complications.

Dot-ELISA for the diagnosis of neurocysticercosis

The aim of the present study was to standardize and evaluate dot-Enzyme linked immunosorbent assay (Dot-ELISA), a simple and rapid test for the detection of cysticercus antibodies in the serum for the diagnosis of neurocysticercosis (NCC). The antigen used in the study was a complete homogenate of Cysticercus cellulosae cysts obtained from infected pigs and dotted on to nitrocellulose membrane. Test sera were collected from the patients of NCC, and control sera from patients with other diseases and healthy students and blood donors of the Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER) Hospital, Pondicherry, during a study period from 2001 to 2003. Dot-ELISA detected antibodies in 14 of 25 (56%) in clinically suspected cases of NCC, 13 of 23 (56.5%) in CT/MRI proven cases of NCC and 2 of 25 (8%) each in non-cysticercal CNS infection controls and healthy controls. The test showed a sensitivity of 56.25%, specificity of 92%, positive predictive value of 87.09%, and negative predictive value of 70.76%. Results of the present study shows that the Dot-ELISA as a simple test can be used in the field or poorly equipped laboratories for diagnosis of NCC .

Single step polymerase chain reaction (PCR) for the diagnosis of the Leishmania (Viannia) subgenus

In Brazil, the main etiologic agent of Leishmaniasis that frequently presents with mucosal involvement belongs to the Viannia subgenus. The therapeutic conduct in this disease depends on the parasitological diagnosis, and classical methods are restricted in identifying the agent. In this paper we describe a polymerase chain reaction (PCR), which uses primers designed from mini-exons repetitive sequences. The PCR amplifies a 177bp fragment that can distinguish (Viannia) from (Leishmania) subgenus. This test could be a useful diagnostic tool.

Use of Distress and Depression Thermometers to Measure Psychosocial Morbidity Among Southern European Cancer Patients

GOALS OF WORK: Recent literature has indicated the need for rapid evaluation of psychosocial issues secondary to cancer. Because of the problems of routine use of psychometric instruments, short instruments such as visual analogue scales or one-item 0-10 scales have been developed as valid assessment alternatives. PATIENTS AND METHODS: A study was conducted to examine the role of two 0-10 scales in measuring emotional stress (distress thermometer, DT) and depressed mood (mood thermometer, MT), respectively, in a multicenter study carried out in southern European countries (Italy, Portugal, Spain, and Switzerland). A convenience sample of 312 cancer outpatients completed the DT and MT and the Hospital Anxiety Depression Scale (HADS). MAIN RESULTS: DT was more significantly associated HADS anxiety than HADS depression while MT was related both to HADS anxiety and depression. The correlation of MT with HADS was higher than DT. A cutoff point >4 on the DT maximized sensitivity (65%) and specificity (79%) for general psychosocial morbidity while a cutoff >5 identified more severe "caseness" (sensitivity=70%; specificity=73%). On the MT, sensitivity and specificity for general psychosocial morbidity were 85% and 72% by using the cutoff score >3. A score >4 on the MT was associated with a sensitivity of 78% and a specificity of 77% in detecting more severe caseness. CONCLUSIONS: Two simple instruments, the DT and the MT, were found to have acceptable levels of sensitivity and specificity in detecting psychosocial morbidity. Compared to the HADS, however, the mood MT performed better than the DT.