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Multispectral optoacoustic tomography (MSOT) utilizes multiple wavelengths to illuminate tissue, producing a series of optoacoustic images rich in spectral information. This approach offers a more comprehensive spectral profile compared to conventional optoacoustic techniques. Contrasted with single-wavelength optoacoustic images, the spectral information can be amalgamated with endogenous chromophores or exogenous dyes within biological organisms, thereby unveiling physiological, cellular, and subcellular functions. The development of eigenspectral optoacoustic tomography (eMSOT), grounded in the linear mixture model (LMM), along with its various derivative methods, facilitates label-free imaging of tissue oxygen saturation in deep-seated structures. However, the effectiveness of the LMM may diminish in the presence of multiple scattering effects or inter-substance interactions, thereby impairing the performance of the eMSOT method in heterogeneous tissues. To address this issue, we propose incorporating a nonlinear model to enhance the eMSOT technique, which we refer to as NL-eMSOT (non-linear eMSOT). This model employs the Hadamard product as a nonlinear component of the LMM, effectively characterizing the interactions between photons and both oxygenated and deoxygenated hemoglobin within the near-infrared spectral window. This innovation resolves the nonlinear unmixing problem inherent in optoacoustic imaging. Our approach, validated through numerical simulations, phantom experiments, and in vivo studies, improves the accuracy of quantitative oxygen saturation estimation in heterogeneous tissues by accounting for inter-substance interactions. Consequently, it necessitates the consideration of more complex mixing models to adequately address nonlinear interactions. [ABSTRACT FROM AUTHOR]

Genus Candida covers more than 50 species, half of which can cause infections in humans. Some of the Candida species exhibit drug resistance; therefore, there is an urgent need for rapid and accurate differentiation for rendering appropriate and effective management. Here, we report a new methodology employing real-time polymerase chain reaction (RTPCR) and melting temperature analyses (MTA) procedures. Fungal ribosomal internal transcribed spacer 2 (ITS2) has been confirmed with variable nucleotide sequences, which makes it possible to differentiate one species from another by checking their melting temperature following PCR amplification. The universal primers (panFg) covering entire ITS2 region, from 5.8S to 28S rRNA genes, were designed to differentially identify most Candida species with RTPCR-MTA procedure. Nucleic acids from five genomes of closely related Candida species, which were experimentally spiked into human blood, were extracted and amplified. PCR amplicons were called for melting temperature of Candida albicans (87.49°C), C. glabrata (86.85°C), C. krusei (90.24°C), C. parapsilosis (86.22°C), and C. tropicalis (86.08°C). The melting temperature of each amplicon was consistent and reproducible in three replicate experiments (SD ± 0.04-0.32). The new RTPCR-MTA methodology showed promise in differential diagnosis of closely related Candida species from environmental and clinical samples. [ABSTRACT FROM AUTHOR]

Brucellosis is a zoonotic infection transmitted from animals to human by ingestion of infected food products, direct contact with an infected animal, or inhalation of aerosols. Brucella infection-induced osteomyelitis may present only with nonspecific clinical and radiographic findings, mild elevations in serum inflammatory markers, as well as nonspecific histological changes. We studied a case of an Iraqi war veteran with multifocal vertebral body and left iliac bone lesions on radio nucleotide scans and magnetic resonance imaging, clinically suspected osteomyelitis possibly because of Brucella. Although histomorphological findings were nonspecific, consisting of chronic inflammatory cell infiltrate and reactive fibrosis, tissue gram and silver impregnation stains of bone biopsies were informative, revealing gram-negative coccobacilli consistent in size with Brucella species. Total nucleic acids were extracted from formalin-fixed paraffin-embedded tissues and amplified by sequential real-time polymerase chain reaction, targeting genes coding (1) outer membrane protein (omp-31) of Brucella species and (2) insertion sequence (IS711) of Brucella abortus (b-abt). Polymerase chain reaction results confirmed B. abortus as the causative pathogens for presumed diagnosis of Brucella osteomyelitis. [ABSTRACT FROM AUTHOR]

Burkholderia pseudomallei and B. mallei are two highly pathogenic bacteria responsible for melioidosis and glanders, respectively. Our laboratory developed hydrolysis probe-based real-time polymerase chain reaction assays targeting type three secretion system (TTS) and transposase family protein (TFP) of B. pseudomallei and B. malli, respectively. The assays were validated for target specificity, amplification sensitivity, and reproducibility. A bacterial DNA panel, composed of B. pseudomallei (13 strains), B. mallei (11 strains), Burkholderia species close neighbors (5 strains), and other bacterial species (17 strains), was prepared for specificity testing. Reference DNAs from B. pseudomallei and B. mallei bacterial cultures were used as controls for amplification, limit of detection, and reproducibility testing. The two TaqMan assays, Bp-TTS 1 and Bm-TFP, were optimized and applied in a retrospective study of archived cases from the Armed Forces Institute of Pathology. We tested 10 formalin-fixed paraffin-embedded blocks originally from autopsy specimens of patients who died of melioidosis or glanders during or after overseas tours in 1960s. Polymerase chain reaction results confirmed that DNA samples from formalin-fixed paraffin-embedded blocks of eight patients with melioidosis were positive for Bp-TTS 1 target and two patients with glanders were positive for Bm-TFP target. [ABSTRACT FROM AUTHOR]