Biomedical subjects

Susan A McCarthy

Publications and source records attributed to Susan A McCarthy.

3 recordsLinked to original sources

PubMed2005

Rapid phenotypic characterization of Vibrio isolates by pyrolysis metastable atom bombardment mass spectrometry.

Pyrolysis mass spectrometry was investigated for rapid characterization of food-borne bacterial pathogens. Nine isolates of Vibrio parahaemolyticus and one isolate each of Vibrio fluvialis, Vibrio hollisae, and Vibrio vulnificus were analyzed. Pyrolysis mass spectra, generated via an alternative ionization method, metastable atom bombardment, were subject to principal component-discriminant analysis. The spectral patterns were used to distinguish Vibrio isolates differing in species, serotype and expression of the thermostable direct hemolysin gene. The patterns of similarity and dissimilarity amongst spectra in the Vibrio test set generally reflected those associated with species, serotype or hemolysin-producing genes, though the combined influence of these and other variables in the multi-dimensional data did not produce a simple clustering with respect to any one of these characteristics. These results suggested that with enough examples to model the most common combinations, the method should be able to characterize Vibrio isolates according to their phenotypic characteristics. Pyrolysis-mass spectrometry with metastable atom bombardment and pattern recognition appeared suitable for rapid infraspecific comparison of Vibrio isolates. This integrated analytical, pattern-recognition system should be examined further for potential utility in clinical and public health diagnostic contexts.

Animals↗

PubMed2004

Autocrine activation by interleukin 1alpha induces the fibrogenic phenotype of systemic sclerosis fibroblasts.

OBJECTIVE: To explore the cellular localization of interleukin 1alpha (IL-1alpha) in cultured fibroblasts from lesional skin of patients with systemic sclerosis (SSc) and to study the role of intracellular IL-1alpha in the activation of fibroblasts. METHODS: Dermal fibroblasts were derived from 12 patients with SSc. Expression of IL-1alpha mRNA was examined using reverse transcriptase-polymerase chain reaction (RT-PCR). The cellular distribution of IL-1alpha was examined by subcellular fractionation, flow cytometry, and immunocytochemistry. A full-length IL-1alpha cDNA was subcloned into the pcDNA3 vector to create sense and antisense-encoding constructs. Normal and SSc fibroblasts were stably transfected with the sense and antisense-encoding constructs, respectively. Stably transfected fibroblast clones were analyzed for the production of procollagen and IL-6 protein by ELISA, alpha1(I) procollagen mRNA by Northern blot hybridization, and proliferation by [3H]thymidine incorporation. RESULTS: SSc-affected fibroblasts constitutively expressed intracellular IL-1alpha, which was predominantly located in the nucleus. Inhibition of IL-1alpha expression in SSc-affected fibroblasts using antisense constructs resulted in decreased proliferation, IL-6 production, and procollagen synthesis. Conversely, overexpression of IL-1alpha in normal fibroblasts resulted in development of the SSc fibroblast phenotype. CONCLUSION: IL-1alpha is an important autocrine fibrogenic factor in SSc, suggesting that inhibition of intracellular IL-1alpha may be a novel strategy for the treatment of SSc.

Autocrine Communication↗

PubMed2002

Defining and using microbial spectral databases.

This work shows how fingerprints of mass spectral patterns from microbial isolates are affected by variations in instrumental condition, by sample environment, and by sample handling factors. It describes a novel method by which pattern distortions can be mathematically corrected for variations in factors not amenable to experimental control. One uncontrollable variable is "between-batch" differences in culture media. Another, relevant for determination of noncultured extracts, is differences between the cells' environmental experience (e.g., starved environmental extracts versus cultured standards). The method suggests that, after a single growth cycle on a solid medium (perhaps, a selective one), pyrolysis MS spectra of microbial isolates can be algorithmically compensated and an unknown isolate identified using a spectral database defined by culture on a different (perhaps, nonselective) medium. This reduces identification time to as few as 24 h from sample collection. The concept also proposes a possible way to compensate certain noncultured, nonisolated samples (e.g., cells concentrated from urine or impacted from aerosol or semi-selectively extracted by immunoaffinity methods from heavily contaminated matrices) for identification within half an hour. Using the method, microbial mass spectra from different labs can be assembled into coherent databases similar to those routinely used to identify pure compounds. This type of data treatment is applicable for rapid detection in biowarfare and bioterror events as well as in forensic, research, and clinical laboratory contexts.

Algorithms↗