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Biomedical subjects

James B Mahony

Publications and source records attributed to James B Mahony.

14 recordsLinked to original sources
PubMed2006

Comparative evaluation of two severe acute respiratory syndrome (SARS) vaccine candidates in mice challenged with SARS coronavirus.

Two different severe acute respiratory syndrome (SARS) vaccine strategies were evaluated for their ability to protect against live SARS coronavirus (CoV) challenge in a murine model of infection. A whole killed (inactivated by beta-propiolactone) SARS-CoV vaccine and a combination of two adenovirus-based vectors, one expressing the nucleocapsid (N) and the other expressing the spike (S) protein (collectively designated Ad S/N), were evaluated for the induction of serum neutralizing antibodies and cellular immune responses and their ability to protect against pulmonary SARS-CoV replication. The whole killed virus (WKV) vaccine given subcutaneously to 129S6/SvEv mice was more effective than the Ad S/N vaccine administered either intranasally or intramuscularly in inhibiting SARS-CoV replication in the murine respiratory tract. This protective ability of the WKV vaccine correlated with the induction of high serum neutralizing-antibody titres, but not with cellular immune responses as measured by gamma interferon secretion by mouse splenocytes. Titres of serum neutralizing antibodies induced by the Ad S/N vaccine administered intranasally or intramuscularly were significantly lower than those induced by the WKV vaccine. However, Ad S/N administered intranasally, but not intramuscularly, significantly limited SARS-CoV replication in the lungs. Among the vaccine groups, SARS-CoV-specific IgA was found only in the sera of mice immunized intranasally with Ad S/N, suggesting that mucosal immunity may play a role in protection for the intranasal Ad S/N delivery system. Finally, the sera of vaccinated mice contained antibodies to S, further suggesting a role for this protein in conferring protective immunity against SARS-CoV infection.

Administration, Intranasal↗
PubMed2005

Interobserver agreement in the interpretation of anal intraepithelial neoplasia.

BACKGROUND: Anal carcinoma incidence is increasing, and is highest among men with human immunodeficiency virus (HIV) infection who have sex with men. Anal carcinoma and anal intraepithelial neoplasia (AIN) are ascertained on tissue histology, but requires invasive procedures. Screening for AIN using anal cytology was suggested. The authors evaluated agreement on cytologic and biopsy specimens from HIV-positive men undergoing anal carcinoma screening. METHODS: One hundred twenty-nine HIV-positive men with a history of anal-receptive intercourse underwent anal cytology, anoscopy, and biopsy. Four pathologists independently assessed cytology and biopsy specimens and reached consensus for discordant cases. RESULTS: Each pathologist evaluated 120 cytology and 155 biopsy specimens. The weighted kappa value for overall agreement was 0.54 (95% confidence interval [CI], 0.49-0.59) for cytology specimens and 0.59 (95%CI, 0.55-0.63) for biopsy specimens. The median kappa values for pairwise agreement among pathologists and for agreement with consensus were, respectively, 0.69 and 0.77 for cytology and 0.66 and 0.75 for biopsy. At least 3 pathologists were in agreement for 92 (76.7%) cytology and 134 (86.5%) biopsy specimens. Reliability for the Bethesda classification system was at least moderate, except for the cytologic category of atypical squamous cells of undetermined significance (kappa = 0.12). Fourteen of 29 (48.3%) cytology specimens and 36 of 47 (76.6%) biopsy specimens with consensus interpretation of high-grade squamous intraepithelial lesions (HSIL) were interpreted originally as HSIL by > or = 3 pathologists. The kappa value for agreement with consensus distinguishing HSIL from non-HSIL ranged from 0.55 to 0.88 for cytology specimens and from 0.76 to 0.94 for biopsy specimens. CONCLUSIONS: Agreement for cytologic and biopsy interpretations was generally at least moderate. Nevertheless, these results supported the need for disease indicators with greater reliability.

Adolescent↗
PubMed2005

Molecular diagnosis of severe acute respiratory syndrome: the state of the art.

Severe acute respiratory syndrome (SARS) first appeared in Guangdong Province, China, in November 2002. Although virus isolation and serology were useful early in the SARS outbreak for diagnosing new cases, these tests are not generally useful because virus culture requires a BSL-3 laboratory and seroconversion is often delayed until 2 to 3 weeks after infection. The first qualitative reverse transcriptase-polymerase chain reaction tests for SARS-coronavirus (CoV) were sensitive and capable of detecting 1 to 10 genome equivalents. These assays were quickly supplemented with quantitative real-time assays that helped elucidate the natural history of SARS, particularly the initial presence of low viral loads in the upper respiratory tract and high viral loads in the lower respiratory tract. The unique natural history of SARS-CoV infection dictates the testing of both respiratory and nonrespiratory specimens, the testing of multiple specimens from the same patient, and sending out positives to be confirmed by a reference laboratory. Commercially available reverse transcriptase-polymerase chain reaction tests for SARS have recently appeared; however, meaningful evaluations of these assays have not yet been performed and their true performance has not been determined. These and other issues related to diagnosis of SARS-CoV infection are discussed in this review.

Animals↗
PubMed2005

Severe acute respiratory syndrome coronavirus nucleocapsid protein expressed by an adenovirus vector is phosphorylated and immunogenic in mice.

Severe acute respiratory syndrome coronavirus (SARS-CoV) has been identified as the aetiological agent of SARS. Thus, vaccination against SARS-CoV may represent an effective approach towards controlling SARS. The nucleocapsid (N) protein is thought to play a role in induction of cell-mediated immunity to SARS-CoV and thus it is important to characterize this protein. In the present study, an E1/partially E3-deleted, replication-defective human adenovirus 5 (Ad5) vector (Ad5-N-V) expressing the SARS-CoV N protein was constructed. The N protein, expressed in vitro by Ad5-N-V, was of the expected molecular mass of 50 kDa and was phosphorylated. Vaccination of C57BL/6 mice with Ad5-N-V generated potent SARS-CoV-specific humoral and T cell-mediated immune responses. These results show that Ad5-N-V may potentially be used as a SARS-CoV vaccine.

Adenoviridae↗
PubMed2004

Performance and Cost evaluation of one commercial and six in-house conventional and real-time reverse transcription-pcr assays for detection of severe acute respiratory syndrome coronavirus.

We evaluated seven reverse transcription-PCR (RT-PCR) assays, including six in-house assays and one commercial assay for the detection of severe acute respiratory syndrome coronavirus (SARS-CoV) RNA in clinical specimens. RT-PCR assays targeted different genomic regions and included three conventional assays (one nested and two non-nested) run on a conventional heat block and four real-time assays performed in a LightCycler (LC; Roche Diagnostics). All in-house assays were optimized for assay parameters, including MgCl2, primer, and probe concentrations. The commercial assay was the RealArt HPA CoV RT-PCR assay (Artus), which was run in the LC. Testing serial dilutions of cultured SARS-CoV showed that the analytical sensitivity of the assays ranged from 10(-8) to 10(-6), corresponding to 1 and 100 copies of viral RNA, respectively. Significant differences in analytical sensitivities were observed between assays (P < 0.01, probit regression analysis for 50% sensitivity levels for the top two assays versus the others). Testing 68 clinical specimens (including 17 respiratory tract specimens, 29 urine samples, and 22 stools or rectal swabs) demonstrated that six of the seven assays detected at least 17 of 18 positives (defined as positive in at least two assays), and two of the assays had a sensitivity of 100%. There were no significant differences in sensitivity between the assays (P = 0.5 [Cochrance Q test, least sensitive 15 of 18 versus 18 of 18]). The specificities of the assays ranged from 94.0 to 100% without significant differences (P = 0.25 to 0.5 [McNemar test]). The reagent and technologist cost of performing the in-house PCR assays ranged from $5.46 to $9.81 Canadian dollars (CDN) per test. The commercial assay cost was considerably higher at $40.37 per test. The results demonstrated good performance for all assays, providing laboratories that need to do SARS RNA testing with a choice of assay formats.

Costs and Cost Analysis↗
PubMed2004

Combining human papillomavirus testing or cervicography with cytology to detect cervical neoplasia.

CONTEXT: Cervicography and oncogenic human papillomavirus (HPV) testing have been proposed for improving the accuracy of cervical cancer screening. OBJECTIVE: To examine whether cervicography and HPV testing can improve beyond chance the detection of cervical intraepithelial neoplasia (CIN) 2 or 3 in women with atypical cells of undetermined significance or low-grade squamous intraepithelial lesions on cytology. DESIGN: Cross-sectional analysis. Oncogenic HPV testing by Hybrid Capture II assay or cervicography combined with cytology was compared with the reference standard of colposcopy with directed biopsy. SETTING: Community family practices. PARTICIPANTS: Three hundred four women with low-grade cytologic abnormality. MAIN OUTCOME MEASURES: The gain in accuracy for detecting histologic CIN 2 or 3 or carcinoma. Because an adjunct test may improve sensitivity by chance alone, the sensitivity or specificity if the second test performed randomly was estimated. RESULTS: Cervical intraepithelial neoplasia 2 or 3 was found in 11.8% (36/304) of the women and invasive squamous cell carcinoma in 0.3% (1/304). The sensitivity of cytology for detecting CIN 2 or 3 was 73.0% and increased by 21.6% to 94.6% with the addition of a cervigram showing a low-grade lesion or higher or a positive HPV test result. These gains were reduced to 8.1% and 10.8% above the sensitivities expected if the additional tests performed randomly. The corresponding specificities decreased from 49.1% to 32.2% and 33.0%. There was insufficient power to determine whether observed sensitivities were statistically significantly higher than the expected sensitivities. CONCLUSION: Adjunctive HPV testing or cervicography may provide similar gains in sensitivity, but they can appear misleadingly large if chance increases are not taken into account.

Adult↗
PubMed2003

Incidence, clearance and predictors of human papillomavirus infection in women.

BACKGROUND: Persistent infection with carcinogenic human papillomavirus (HPV) is linked to high-grade lesions and cervical cancer. To better understand the natural history of HPV, we sought to determine the rates of incident and cleared carcinogenic HPV infection, by age, among women aged 15-49 years and to explore risk factors for incident infection. METHODS: Women enrolled in an earlier HPV prevalence survey (500 of 800 who were HPV-negative and all 121 who were HPV-positive) were invited to participate in follow-up HPV testing at their periodic health examination one year later. A cervical soft-brush specimen for HPV testing and a smear for cytologic examination were obtained, and participants completed a questionnaire on their demographic characteristics and sexual history. RESULTS: Two hundred and fifty-three (50.6%) previously HPV-negative women and 54 (44.6%) previously HPV-positive women were retested. The mean interval between visits was 14.0 (standard deviation 2.0, median 13.5, range 9.0-21.3) months. Incident HPV infection occurred in 11.1% (28/253) of the women overall, with the highest rate, 25.0% (6/24), in the 15-19-year age group. In the univariate analyses, risk factors for incident HPV were the median number of sexual partners in the past year (< or = 1 v. > or = 2: odds ratio [OR] 8.2, 95% confidence interval [CI] 3.0-22.2; p < 0.001) and the median number of sexual partners over a lifetime (> 3 v. < or = 3: OR 3.0, 95% CI 1.2-7.2; p = 0.014). In multivariate logistic regression modelling adjusted for age, median number of sexual partners in the past year, median number of sexual partners over a lifetime, marital status, current smoking and current use of oral contraceptives, only the median number of sexual partners in the past year remained significantly associated with incidence (OR 6.2, 95% CI 1.6-24.5; p = 0.009). Of the previously HPV-positive women, 51.9% (28/54) had cleared the infection. INTERPRETATION: Incident infection with carcinogenic HPV was highest in women aged 15-19 years, and risk factors were consistent with a sexually transmitted infection. A large proportion of the women who were HPV-positive appeared to have cleared the infection after one year.

Adolescent↗
PubMed2003

Adjunctive human papillomavirus testing in the 2-year follow-up of women with low-grade cervical cytologic abnormalities: a randomized trial and economic evaluation.

CONTEXT: Although human papillomavirus (HPV) testing may aid in managing low-grade abnormality on screening cervical cytology, patient compliance with repeat testing programs requires consideration. OBJECTIVES: To determine effectiveness and costs of repeated Papanicolaou (Pap) test and oncogenic HPV testing for detecting cervical intraepithelial neoplasia 2 or 3. DESIGN: We conducted a randomized controlled trial of combined Pap test and cervical HPV testing by Hybrid Capture 1 test compared with Pap test alone; tests were performed every 6 months for up to 2 years. The study end point was colposcopic examination performed on all women at 2 years, or earlier if an HPV test was positive or if a Pap test showed high-grade squamous intraepithelial lesion. SETTING: Sixty-six community family practices. PARTICIPANTS: Two hundred fifty-seven women with atypical squamous cells of undetermined significance or low-grade squamous intraepithelial lesion on screening cervical cytology. MAIN OUTCOME MEASURES: Detection of histologically confirmed cervical intraepithelial neoplasia 2 or 3, fully allocated costs, and loss to follow-up. RESULTS: Combined Pap test and HPV testing detected 11 (100%) of 11 cases of cervical intraepithelial neoplasia 2/3, whereas Pap test alone detected 7 (63.6%) of these 11 cases (P =.14); corresponding specificities were 39 (46.4%) of 84 and 45 (71.4%) of 63 (P =.005). The cost-effectiveness ratio was Can $4456 per additional case of high-grade cervical intraepithelial neoplasia. Sixty-nine (26.8%) of the 257 women (24.6% combined group vs 29.1% Pap test only group, P =.41) defaulted from testing or from colposcopy when referred with an abnormal result. CONCLUSIONS: Combined testing was more costly but may detect more cases of cervical intraepithelial neoplasia 2/3 than Pap test alone. However, poor adherence limits usefulness of a management strategy that requires repeated follow-up.

Adult↗
PubMed2002

Smoking, season, and detection of Chlamydia pneumoniae DNA in clinically stable COPD patients.

BACKGROUND: The prevalence and role of Chlamydia pneumoniae in chronic obstructive pulmonary disease (COPD) remain unclear, and molecular methods of detection may help clarify this relationship. METHODS: Consecutive clinically stable patients with smoking-related COPD attending a tertiary care outpatient clinic were enrolled in this cross-sectional study. Peripheral blood mononuclear cells were obtained from 100 patients, and induced sputum was obtained in 62 patients. C. pneumoniae DNA was detected in blood or sputum by nested polymerase chain reaction (PCR). RESULTS: Patients had mean age (standard deviation) of 65.8 (10.7) years, mean forced expiratory volume in one second (SD) of 1.34 (0.61) L, and 61 (61.0%) were male. C. pneumoniae nucleic acids were detected in 27 (27.0%) patients. Among 62 patients with both blood and sputum available, blood specimens were superior to induced sputum for detection of C. pneumoniae DNA (21 versus 7 detected, P=0.003). Current smoking (odds ratio [OR]=2.6, 95 % confidence interval [CI]: 1.1, 6.6, P=0.04), season (November to April) (OR=3.6, 95% CI: 1.4, 9.2, P=0.007), and chronic sputum production (OR=6.4, 95% CI: 1.8, 23.2, P=0.005) were associated with detection of C. pneumoniae DNA. CONCLUSIONS: C. pneumoniae DNA prevalence was higher among current smokers, and during winter/spring months. Prospective molecular studies are needed to examine the role of C. pneumoniae detection in COPD disease symptoms and progression.

Aged↗
PubMed2002

Chlamydia pneumoniae infection of endothelial cells induces transcriptional activation of platelet-derived growth factor-B: a potential link to intimal thickening in a rabbit model of atherosclerosis.

Smooth muscle cell (SMC) proliferation and intimal thickening are hallmark features of atherosclerotic disease, and Chlamydia pneumoniae may contribute to atherogenesis by imparting biological effects on SMCs. An in vitro endothelial cell model and a normocholesterolemic rabbit model were used to test the hypothesis that infection with C. pneumoniae induces SMC growth factor production, SMC proliferation, and aortic intimal thickening. Using reverse-transcriptase polymerase chain reaction, it was demonstrated that C. pneumoniae infection of endothelial cells induced platelet-derived growth factor (PDGF)-B messenger RNA expression. In C. pneumoniae-infected rabbits, maximum intimal thickness (MIT) was significantly greater than that in uninfected animals (P< .0001). MIT correlated with the presence of C. pneumoniae antigen (P= .043) and PDGF-B (P= .002) in aortic tissues, and C. pneumoniae antigen was independently correlated with the presence of PDGF-B in aortic tissues (P= .009). These results suggest that C. pneumoniae-induced SMC proliferation and intimal thickening may be mediated through PDGF-B and may be a molecular mechanism by which C. pneumoniae infection could contribute to atherogenesis.

Animals↗
PubMed2002

Identification of MEK- and phosphoinositide 3-kinase-dependent signalling as essential events during Chlamydia pneumoniae invasion of HEp2 cells.

The ability of Chlamydia pneumoniae to survive and cause disease is predicated on efficient invasion of cellular hosts. While it is recognized that chlamydial determinants are important for mediating attachment and uptake into non-phagocytic cells, little is known about the bacterial ligands and cellular receptors that facilitate invasion or host cell signal transduction pathways implicated in this process. We used transmission and scanning electron microscopy to demonstrate that attachment of bacteria to host cells induced the appearance of microvilli on host cell membranes. Invasion occurred 30-120 min after cell contact with the subsequent loss of membrane microvilli. Using an epithelial cell infection model, C. pneumoniae invasion caused a rapid and sustained increase in MEK-dependent phosphorylation and activation of ERK1/2, followed by PI 3-kinase-dependent phosphorylation and activation of Akt. Tyrosine phosphorylation of focal adhesion kinase (FAK) preceded its appearance in a complex with the p85 subunit of PI 3-kinase during chlamydial invasion and isoform-specific tyrosine phosphorylation of the docking protein Shc also occurred at the time of attachment and entry of bacteria. Chlamydia entry but not attachment could be abrogated with specific inhibitors of MEK, PI 3-kinase and actin polymerization, demonstrating the importance of these signalling pathways and an intact actin cytoskeleton for C. pneumoniae invasion. These results suggest that activation of specific cell signalling pathways is an essential strategy used by C. pneumoniae to invade epithelial cells.

Actins↗
PubMed2002

Chlamydiae host cell interactions revealed using DNA microarrays.

Chlamydiae are obligate intracellular bacterial parasites that infect eukaryotic cells and live their entire life cycle within a cytoplasmic vacuole or inclusion. We have employed cDNA microarray and conventional biological approaches to study the pathogen-host cell interaction during C. pneumoniae infection of eukaryotic cells. Two host cell signaling pathways, MEK/ERK and PI 3-kinase/Akt, were activated within 5 and 20 minutes, respectively, following infection with chlamydiae. Pharmacological inhibition of these pathways blocked invasion of HEp2 cells indicating that activation of these pathways was required for infection. Rho family GTPase activity was essential for invasion, since the pan-Rho GTPase inhibitor, compactin, blocked infection of HEp2 cells. cDNA microarrays and reverse transcriptase PCR were used to study host cell and chlamydial gene expression during the replication cycle. Analysis of host cell gene expression following infection with C. pneumoniae indicated that genes coding for cytokines, growth factors, and signaling molecules were upregulated, as early as 2 hours postinfection. Analysis of chlamydial gene expression indicated a temporal regulation of transcription with distinct early-, mid-, and late-cycle classes of RNA transcripts. Newly discovered genes encoding three Ser/Thr protein kinases and one protein phosphatase were upregulated 6-12 hours postinfection. One protein kinase, designated CpnPK1, was first detected at 12 hours postinfection, accumulated in the inclusion throughout the replication cycle, and may be a type III effector molecule. An increased understanding of chlamydial host cell interactions, in particular the role of various chlamydial proteins in infection and identification of essential virulence factors should provide novel targets for the development of new antimicrobials.

Animals↗
PubMed2002

Influence of clarithromycin on early atherosclerotic lesions after Chlamydia pneumoniae infection in a rabbit model.

Chlamydia pneumoniae may play a role in atherogenesis and vascular diseases, and antibiotics may prove useful in these conditions. Three groups of New Zealand White rabbits (24 per group) were infected via the nasopharynx with C. pneumoniae on three separate occasions (2 weeks apart). Group I was untreated and sacrificed at 12 weeks; group II received clarithromycin at 20 mg/kg/day for 8 days, beginning 5 days after each inoculation (early treatment); and group III received a similar dose of clarithromycin starting 2 weeks after the third inoculation and continued for 6 weeks thereafter (delayed treatment). To test for a possible anti-inflammatory effect of clarithromycin, two other groups of uninfected rabbits (12 animals in each) were fed 0.5% cholesterol-enriched chow, and one of these groups was treated with clarithromycin at 30 mg/kg/day for 6 weeks. Of 23 untreated infected rabbits, 8 developed early lesions of atherosclerosis, whereas 2 of the 24 early-treated group II had similar changes (P = 0.036 [75% efficacy]). However, in the delayed-treatment group, group III, 3 of 24 rabbits developed early lesions of atherosclerosis, thus demonstrating 62.5% reduction compared to the untreated controls (P = 0.07 [trend to statistical significance]). C. pneumoniae antigen was detected in 8 of 23 group I (untreated) rabbits versus 1 of 24 of the early-treated (group II) rabbits and 4 of 24 animals in the delayed group III (P = 0.009 and 0.138, respectively). All of the untreated, cholesterol-fed rabbits had moderate to advanced atherosclerosis (grade III or IV); clarithromycin had no effect on reducing the prevalence of but did reduce the extent of atherosclerosis in the cholesterol-fed rabbits by 17% compared to untreated controls. Thus, clarithromycin administration modified C. pneumoniae-induced atherosclerotic lesions and reduced the ability to detect organism in tissue. Early treatment was more effective than delayed treatment.

Animals↗