Serodiagnosis as adjunct assay for pertussis infection in São Paulo, Brazil.

Pertussis remains an important public health problem in many countries despite extensive immunization. Cultures and real-time PCR (RT-PCR) assays are the recommended pertussis diagnostic tests, but they lack sensitivity at the later stage of the disease. This study introduces the IgG anti-pertussis toxin enzyme-linked immunosorbent assay (PT ELISA) in our routine diagnosis to improve disease burden estimation. Serum samples and nasopharyngeal swabs (n = 503) were collected at the same time from patients presenting with cough illness suspected of being pertussis and tested by the PT ELISA and culture and/or RT-PCR, respectively. Patients were separated into three age groups: group 1, <1 year (n = 260; mean age, 3 months), group 2, 1 to 6 years (n = 81; mean age, 3 years), and group 3, ≥7 years (n = 162; mean age, 26 years). The times (means) from cough onset to specimen collection were 16, 24, and 26 days, respectively. In group 1, 83 (82.2%) of 101 positive cases were positive for pertussis by culture/RT-PCR, while 40 (39.6%) tested positive by PT ELISA. In group 2, 6 (19.4%) of 31 positive cases were culture/RT-PCR positive, and 29 (93.6%) were seropositive. In group 3, 13 (13.8%) of 94 positive cases were positive by culture/RT-PCR and 91 (96.8%) were positive by serology. Culture/RT-PCR detected more cases of pertussis in infants (P < 0.0001), whereas the PT ELISA detected more cases in adolescents and adults (P < 0.0001). The timing between cough onset and specimen collection or recent vaccination may have partially affected our results. Serology is a suitable, cost-effective, and complementary pertussis diagnostic tool, especially among older children, adolescents, and adults during the later disease phase.

Lipid bodies are reservoirs of cyclooxygenase-2 and sites of prostaglandin-E2 synthesis in colon cancer cells.

Lipid bodies (lipid droplets) are emerging as dynamic organelles involved in lipid metabolism and inflammation. Increased lipid body numbers have been described in tumor cells; however, its functional significance in cancer has never been addressed. Here, we showed increased number of lipid bodies in tumor tissues from patients with adenocarcinoma of colon submitted to surgical resection when compared with an adjacent normal tissue. Accordingly, increased numbers of lipid bodies were observed in human colon adenocarcinoma cell lines and in a H-rasV12-transformed intestinal epithelial cell line (IEC-6 H-rasV12) compared with nontransformed IEC-6 cells. The functions of lipid bodies in eicosanoid synthesis in cancer cells were investigated. CACO-2 cells have increased expression of cyclooxygenase-2 (COX-2) when compared with IEC-6 cells. We showed by immunolocalization that, in addition to perinuclear stain, COX-2 and prostaglandin E (PGE) synthase present punctate cytoplasmic localizations that were concordant with adipose differentiation-related protein-labeled lipid bodies. The colocalization of COX-2 at lipid bodies was confirmed by immunoblot of subcellular fractionated cells. Direct localization of PGE(2) at its synthesis locale showed that lipid bodies are sources of eicosanoids in the transformed colon cancer cells. Treatment with either aspirin or the fatty acid synthase inhibitor C75 significantly reduced the number of lipid bodies and PGE(2) production in CACO-2 and in IEC-6 H-rasV12 cells with effects in cell proliferation. Together, our results showed that lipid bodies in colon cancer cells are dynamic and functional active organelles centrally involved in PGE(2) synthesis and may potentially have implications in the pathogenesis of adenocarcinoma of colon.