Occupational Exposure to Pfiesteria Species in Estuarine Waters Is Not a Risk Factor for Illness

BACKGROUND: Exposure to the dinoflagellate Pfiesteria has, under certain circumstances, been associated with deficits in human learning and memory. However, uncertainties remain about the health risk of chronic, low-level exposures (as seen among occupationally exposed commercial fishermen), particularly in light of studies suggesting that Pfiesteria strains are widespread in the estuarine environment in the U.S. mid-Atlantic region. METHODS: We selected an initial cohort of 152 persons, including 123 persons with regular, occupational exposure to the Chesapeake Bay; 107 of the cohort members were followed for the full four summer “seasons” of the study. Cohort members were questioned biweekly about symptoms, and data were collected about the areas of the bay in which they worked. These latter data were matched with data on the presence or absence of Pfiesteria in each area, based on polymerase chain reaction analysis of > 3,500 water samples. Cohort members underwent neuropsychological testing at the beginning and end of each summer season. RESULTS: No correlation was found between work in an area where Pfiesteria was identified and specific symptomatology or changes on neuropsychological tests. CONCLUSIONS: Although high-level or outbreak-associated exposure to Pfiesteria species (or specific strains within a species) may have an effect on health, routine occupational exposure to estuarine environments in which these organisms are present does not appear to pose a significant health risk

Maternal Administration of Solithromycin, a New, Potent, Broad-Spectrum Fluoroketolide Antibiotic, Achieves Fetal and Intra-Amniotic Antimicrobial Protection in a Pregnant Sheep Model

Solithromycin (CEM-101) is a new antibiotic that is highly potent against Ureaplasma and Mycoplasma spp. and active against many other antibiotic-resistant organisms. We have explored the maternal-amniotic-fetal pharmacokinetics of CEM-101 in a pregnant sheep model to assess its potential for treating intrauterine and antenatal infection. Chronically catheterized pregnant ewes (n = 6 or 7) received either a single maternal intravenous (i.v.) infusion of CEM-101 (10 mg/kg of body weight), a single intra-amniotic (i.a.) injection (1.4 mg/kg of estimated fetal weight), or a combined i.v. and i.a. dose. Maternal plasma (MP), fetal plasma (FP), and amniotic fluid (AF) samples were taken via catheter at intervals of 0 to 72 h postadministration, and concentrations of solithromycin and its bioactive polar metabolites (N-acetyl [NAc]–CEM-101 and CEM-214) were determined. Following maternal i.v. infusion, peak CEM-101 concentrations in MP, FP, and AF were 1,073, 353, and 214 ng/ml, respectively, representing a maternal-to-fetal plasma transfer efficiency of 34%. A single maternal dose resulted in effective concentrations (>30 ng/ml) in MP, FP, and AF sustained for >12 h. NAc–CEM-101 and CEM-214 exhibited delayed accumulation and clearance in FP and AF, resulting in an additive antimicrobial effect (>48 h). Intra-amniotic solithromycin injection resulted in elevated (∼50 μg/ml) and sustained CEM-101 concentrations in AF and significant levels in FP, although the efficiency of amniotic-to-fetal transfer was low (∼1.5%). Combined i.v. and i.a. administration resulted in primarily additive concentrations of CEM-101 in all three compartments. Our findings suggest that CEM-101 may provide, for the first time, an effective antimicrobial approach for the prevention and treatment of intrauterine infection and early prevention of preterm birth

SOCS1 and SOCS3 Are Targeted by Hepatitis C Virus Core/gC1qR Ligation To Inhibit T-Cell Function

T cells play an important role in the control of hepatitis C virus (HCV) infection. We have previously demonstrated that the HCV core inhibits T-cell responses through interaction with gC1qR. We show here that core proteins from chronic and resolved HCV patients differ in sequence, gC1qR-binding ability, and T-cell inhibition. Specifically, chronic core isolates bind to gC1qR more efficiently and inhibit T-cell proliferation as well as gamma interferon (IFN-γ) production more profoundly than resolved core isolates. This inhibition is mediated by the disruption of STAT phosphorylation through the induction of SOCS molecules. Silencing either SOCS1 or SOCS3 by small interfering RNA dramatically augments the production of IFN-γ in T cells, thereby abrogating the inhibitory effect of core. Additionally, the ability of core proteins from patients with chronic infections to induce SOCS proteins and suppress STAT activation greatly exceeds that of core proteins from patients with resolved infections. These results suggest that the HCV core/gC1qR-induced T-cell dysfunction involves the induction of SOCS, a powerful inhibitor of cytokine signaling, which represents a novel mechanism by which a virus usurps the host machinery for persistence

Use of Molecular Probes to Assess Geographic Distribution of Pfiesteria Species

International audienc

Discovery of the toxic dinoflagellate Pfiesteria in northern European waters.

Several dinoflagellate strains of the genus Pfiesteria were isolated by culturing techniques from sediment samples taken in the Oslofjord region of Norway. Pfiesteria piscicida, well known as a fish killer from the Atlantic coast of America, was identified by genetic methods and light microscopy. The related species Pfiesteria shumwayae was attracted from the sediment by the presence of fish, and has proved toxic. This present survey demonstrates the wide distribution of these potentially harmful species, but so far they have not been connected with fish kills in Europe

Use of renal allografts from donors positive for hepatitis B core antibody confers minimal risk for subsequent development of clinical hepatitis B virus disease

Background. The risk associated with transplantation of renal allografts from hepatitis B virus core antibody-positive (HBcAb(+)), hepatitis B virus surface antigen-negative (HBsAg(-)) donors is not well defined. Methods. Over 4 years, we performed 45 kidney transplants from IgG HBcAb(+), IgM HBcAb(-), HBsAg(-) donors into recipients with a history of prior hepatitis B virus (HBV) infection or reported vaccination. We examined HBV-related outcomes in these 45 patients, in comparison with 45 recipients of allografts from HBcAb(-) donors (matched for transplant type, date, and pretransplant HBV antibodies). We sought evidence for HBV transmission by testing posttransplant sera for the presence of HBcAb, hepatitis B virus surface antibody, and HBsAg. Additionally, we analyzed alanine aminotransferase profiles and allograft survival rates for all patients. Results. No patient receiving an allograft from an HBcAb(+) donor developed clinical HBV infection. No patient receiving an allograft from an HBcAb(+) donor had HBsAg detected through retrospective testing of stored sera or through prospective routine clinical evaluation and care. However, among the HBcAb(+) kidney recipients, 27% developed new HBcAb and/or hepatitis B virus surface antibody after transplant; in contrast, only 4% of control patients developed new antibody responses (relative risk=4.94; confidence interval 1.07-22.83). Among the recipients of HBcAb(+) organs, 18% developed elevated transaminases after transplant, in comparison with 36% of the controls. No association was found between \u27seroconverter\u27 status and elevated alanine aminotransferase profiles in either group. Conclusions. Transplantation of renal allografts from HBcAb(+), HBsAg(-) donors was not associated with clinically detectable HBV disease or antigenemia. However, recipients had a significantly increased risk of HBV seroconversion, consistent with exposure to HBV antigen. These results suggest that HBcAb(+) kidneys can be safely used if transplanted into appropriate recipients, but highlight the need for effective HBV vaccination and vaccine-response monitoring in potential recipients