Detection of prostate cancer by Raman spectroscopy: A multivariate study on patients with normal and altered PSA values.

Digital rectal examination (DRE) was the primary means to detect prostate diseases. The DRE has a high variability as it is based manly in the tactile sensitivity and expertise of the examiner. The prostate-specific antigen (PSA) test was initially developed for surveillance of prostate cancer and later it was also used as a diagnosis test. Raman spectroscopy is a powerful analytical technique that can measure the chemical composition of complex biological samples, such as body fluids. Biochemical changes caused by diseases can lead to significant changes in the Raman spectra. This study aimed to identify the differences in the Raman spectra of serum samples with normal and altered PSA values and correlate these differences by using multivariate techniques (principal component analysis - PCA and partial least squares regression - PLS). A total of 321 spectra were collected from 108 subjects. Two hundred and seventy were obtained from 91 non-altered PSA samples and 51 spectra from 17 samples with altered PSA. Each spectrum acquired was standardized to the area under the curve (1-norm). Discriminating and quantitative models employing PCA and PLS were developed. The PCA analyses showed 85.7% predictive power (87.41% sensitivity and 76.47% specificity). The PLS test showed a near-perfect sensitivity (98.51%) and an intermediate specificity (62.75%). The quantitative model through PLS regression showed a good correlation between PSA values and the spectral features (r = 0.605). This preliminary study suggests that Raman spectroscopy could be efficiently used for screening patients with altered PSA as well as for follow-up of the treatment of the prostate cancer by using initially the PLS to identify the possible presence of the prostate cancer and later on use de PCA to confirm the diagnosis.

Development of a rapid agglutination latex test for diagnosis of enteropathogenic and enterohemorrhagic Escherichia coli infection in developing world: defining the biomarker, antibody and method.

BACKGROUND: Enteropathogenic and enterohemorrhagic Escherichia coli (EPEC/EHEC) are human intestinal pathogens responsible for diarrhea in both developing and industrialized countries. In research laboratories, EPEC and EHEC are defined on the basis of their pathogenic features; nevertheless, their identification in routine laboratories is expensive and laborious. Therefore, the aim of the present work was to develop a rapid and simple assay for EPEC/EHEC detection. Accordingly, the EPEC/EHEC-secreted proteins EspA and EspB were chosen as target antigens. METHODOLOGY: First, we investigated the ideal conditions for EspA/EspB production/secretion by ELISA in a collection of EPEC/EHEC strains after cultivating bacterial isolates in Dulbecco's modified Eagle's medium (DMEM) or DMEM containing 1% tryptone or HEp-2 cells-preconditioned DMEM, employing either anti-EspA/anti-EspB polyclonal or monoclonal antibodies developed and characterized herein. Subsequently, a rapid agglutination latex test (RALT) was developed and tested with the same collection of bacterial isolates. PRINCIPAL FINDINGS: EspB was defined as a biomarker and its corresponding monoclonal antibody as the tool for EPEC/EHEC diagnosis; the production of EspB was better in DMEM medium. RALT assay has the sensitivity and specificity required for high-impact diagnosis of neglected diseases in the developing world. CONCLUSION: RALT assay described herein can be considered an alternative assay for diarrhea diagnosis in low-income countries since it achieved 97% sensitivity, 98% specificity and 97% efficiency.

Transbronchial biopsy with virtual CT bronchoscopy and nodal highlighting.

Transbronchial biopsy to sample lymph nodes and tumors that are not visible at endoscopy has a poor (<50%) success rate. These nodes can be highlighted easily at virtual computed tomographic (CT) bronchoscopy to provide a guide. This study was performed to evaluate if the addition of this information to the bronchoscopist improved the success rate of transbronchial biopsy of subcarinal and aortopulmonary lymph nodes. The addition of virtual CT bronchoscopy with lymph node highlighting significantly (P < .5) increased biopsy success rates for pretracheal, hilar, and high pretracheal adenopathy.