Performance Evaluation of Fast Microfluidic Thermal Lysis of Bacteria for Diagnostic Sample Preparation.

Development of new diagnostic platforms that incorporate lab-on-a-chip technologies for portable assays is driving the need for rapid, simple, low cost methods to prepare samples for downstream processing or detection. An important component of the sample preparation process is cell lysis. In this work, a simple microfluidic thermal lysis device is used to quickly release intracellular nucleic acids and proteins without the need for additional reagents or beads used in traditional chemical or mechanical methods (e.

Microfluidic-Based Amplification-Free Bacterial DNA Detection by Dielectrophoretic Concentration and Fluorescent Resonance Energy Transfer Assisted in Situ Hybridization (FRET-ISH).

Although real-time PCR (RT-PCR) has become a diagnostic standard for rapid identification of bacterial species, typical methods remain time-intensive due to sample preparation and amplification cycle times. The assay described in this work incorporates on-chip dielectrophoretic capture and concentration of bacterial cells, thermal lysis, cell permeabilization, and nucleic acid denaturation and fluorescence resonance energy transfer assisted in situ hybridization (FRET-ISH) species identification. Combining these techniques leverages the benefits of all of them, allowing identification to be accomplished completely on chip less than thirty minutes after receipt of sample, compared to multiple hours required by traditional RT-PCR and its requisite sample preparation.

Infectious disease immunohistochemistry in placentas from HIV-positive and HIV-negative patients.

Studies comparing placental pathology between human immunodeficiency virus (HIV)-positive and HIV-negative patients have shown conflicting results. In addition, few studies have evaluated the infectious etiology of placental inflammation in HIV-positive patients. We examined a cohort of placentas from 73 HIV-positive and 41 HIV-negative patients to gain a better understanding of the spectrum of placental inflammatory lesions.

Usefulness of immunohistochemical diagnosis of streptococcus pneumoniae in formalin-fixed, paraffin-embedded specimens compared with culture and gram stain techniques.

Streptococcus pneumoniae is the most frequent cause of pneumonia and meningitis. Because S pneumoniae can colonize the upper respiratory tract and antibiotic treatment may inhibit growth, culture-based diagnosis can be problematic. An immunohistochemical assay using a polyclonal antibody against pneumococci was used to test formalin-fixed, paraffin-embedded tissue samples from 46 patients for whom bacterial culture results were available.

Severe acute respiratory syndrome coronavirus infection of mice transgenic for the human Angiotensin-converting enzyme 2 virus receptor.

Animal models for severe acute respiratory syndrome (SARS) coronavirus infection of humans are needed to elucidate SARS pathogenesis and develop vaccines and antivirals. We developed transgenic mice expressing human angiotensin-converting enzyme 2, a functional receptor for the virus, under the regulation of a global promoter. A transgenic lineage, designated AC70, was among the best characterized against SARS coronavirus infection, showing weight loss and other clinical manifestations before reaching 100% mortality within 8 days after intranasal infection.

Histopathologic and immunohistochemical features of fatal influenza virus infection in children during the 2003-2004 season.

Background: The Centers for Disease Control and Prevention enhanced national surveillance for influenza-associated deaths among children because of early reports of pediatric deaths during the 2003-2004 influenza season.

Methods: We studied lung and upper airway specimens from 47 case patients who died who had at least 1 positive result for influenza virus tests using hematoxylin and eosin, special stains for bacteria and fungi, and immunohistochemical (IHC) assays for influenza A and B viruses and other potential viral and bacterial respiratory pathogens.

Results: Nineteen (40%) of the 47 patients were View Article and Find Full Text PDF

Transmission of lymphocytic choriomeningitis virus by organ transplantation.

Background: In December 2003 and April 2005, signs and symptoms suggestive of infection developed in two groups of recipients of solid-organ transplants. Each cluster was investigated because diagnostic evaluations were unrevealing, and in each a common donor was recognized.

Methods: We examined clinical specimens from the two donors and eight recipients, using viral culture, electron microscopy, serologic testing, molecular analysis, and histopathological examination with immunohistochemical staining to identify a cause.

Immunohistochemical, in situ hybridization, and ultrastructural localization of SARS-associated coronavirus in lung of a fatal case of severe acute respiratory syndrome in Taiwan.

This article describes the pathological studies of fatal severe acute respiratory syndrome (SARS) in a 73-year-old man during an outbreak of SARS in Taiwan, 2003. Eight days before onset of symptoms, he visited a municipal hospital that was later identified as the epicenter of a large outbreak of SARS. On admission to National Taiwan University Hospital in Taipei, the patient experienced chest tightness, progressive dyspnea, and low-grade fever.

Prior infection and passive transfer of neutralizing antibody prevent replication of severe acute respiratory syndrome coronavirus in the respiratory tract of mice.

Following intranasal administration, the severe acute respiratory syndrome (SARS) coronavirus replicated to high titers in the respiratory tracts of BALB/c mice. Peak replication was seen in the absence of disease on day 1 or 2, depending on the dose administered, and the virus was cleared within a week. Viral antigen and nucleic acid were detected in bronchiolar epithelial cells during peak viral replication.