Mary DeHart

Group B streptococcus serotype prevalence in reproductive-age women at a tertiary care military medical center relative to global serotype distribution

BackgroundGroup B Streptococcus (GBS) serotype (Ia, Ib, II-IX) correlates with pathogen virulence and clinical prognosis. Epidemiological studies of seroprevalence are an important metric for determining the proportion of serotypes in a given population. The purpose of this study was to evaluate the prevalence of individual GBS serotypes at Madigan Healthcare System (Madigan), the largest military tertiary healthcare facility in the Pacific Northwestern United States, and to compare seroprevalences with international locations.MethodsTo determine serotype distribution at Madigan, we obtained GBS isolates from standard-of-care anogenital swabs from 207 women of indeterminate gravidity between ages 18-40 during a five month interval. Serotype was determined using a recently described molecular method of polymerase chain reaction by capsular polysaccharide synthesis (cps) genes associated with pathogen virulence.ResultsSerotypes Ia, III, and V were the most prevalent (28%, 27%, and 17%, respectively). A systematic review of global GBS seroprevalence, meta-analysis, and statistical comparison revealed strikingly similar serodistibution at Madigan relative to civilian-sector populations in Canada and the United States. Serotype Ia was the only serotype consistently higher in North American populations relative to other geographic regions (p < 0.005). The number of non-typeable isolates was significantly lower in the study (p < 0.005).ConclusionThis study establishes PCR-based serotyping as a viable strategy for GBS epidemiological surveillance. Our results suggest that GBS seroprevalence remains stable in North America over the past two decades.

Does telomerase activity add to the value of fine needle aspirations in evaluating thyroid nodules

BACKGROUND Telomerase replaces DNA sequences that are lost with cell division. Increased activity has been documented in malignant cells. Fine needle aspiration (FNA) has a 90% sensitivity for diagnosis of papillary carcinomas, but a specificity of 52%. This often leads to unnecessary surgery. METHODS Telomeric repeat amplification protocol assays were performed on FNA specimens of thyroid nodules in 19 patients. These results were compared with the surgical pathology using chi-square analysis. RESULTS There were 5 malignant and 14 benign nodules. Telomerase activity was found in 3 of 5 malignant (60%) and 9 of 14 benign (64%): sensitivity was 60%, specificity was 36%. CONCLUSION Telomerase assays did not add any additional information to FNA alone. Inflammatory changes associated with benign and malignant lesions can possess telomerase activity independent of the malignant state.

Effect of Dexamethasone Administered With Magnesium Sulfate on Inflammation-Mediated Degradation of the Blood–Brain Barrier Using an In Vitro Model

Patients at risk for preterm delivery are frequently administered both antenatal steroids for fetal maturation and magnesium sulfate for neuroprotection. In this study, we investigate whether steroids coadministered with magnesium sulfate preserve blood–brain barrier integrity in neuroinflammation. Human umbilical vein endothelial cells were grown in astroglial conditioned media in a 2-chamber cell culture apparatus. Treatment with tumor necrosis factor-α (TNF-α) or catalytically active recombinant matrix metalloproteinase 9 (MMP-9) simulated neuroinflammation. Membrane integrity was assessed by zona occludens 1 (ZO-1) immunoreactivity, permeability to fluorescently conjugated dextran, and transendothelial electrical resistance (TEER). The TNF-α and MMP-9 treatment increased the rate of dextran transit, decreased TEER, and decreased ZO-1 immunoreactivity at junctional interfaces. Dexamethasone pretreatment alone or in combination with 0.5 mmol/L magnesium sulfate preserved monolayer integrity after inflammatory insult. Magnesium sulfate alone was not protective. This study supports a possible interaction between steroids and magnesium in neuroprotection.