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K Kavanagh

Publications and source records attributed to K Kavanagh.

At least 19 recordsLinked to original sources
PubMed2004

Detection of Aspergillus fumigatus mycotoxins: immunogen synthesis and immunoassay development.

Immunological detection of secreted low molecular weight toxins represents a potentially novel means of diagnosing infection by the fungus Aspergillus fumigatus. Two such metabolites, gliotoxin and helvolic acid, were selected and conjugated to thyroglobulin for antisera generation in rabbits. Gliotoxin was initially activated using N-[p-maleimidophenyl] isocyanate (PMPI) and subsequently conjugated to S-acetyl thioglycolic acid N-hydroxysuccinimide-activated thyroglobulin, whereas helvolic acid was activated with N-(3-Dimethylaminopropyl)-N'-ethylcarbodiimide (EDC) in the presence of thyroglobulin prior to immunisation. To facilitate subsequent antisera evaluation, both toxins were similarly conjugated to bovine serum albumin (BSA). Matrix-Assisted Laser Desorption Ionisation-Time Of Flight (MALDI-TOF) mass spectrometry and SDS-PAGE analysis confirmed covalent attachment of toxins to BSA in the ratios of 15 and 2.4 mol per mol BSA for gliotoxin and helvolic acid, respectively. Resultant high titer antisera were capable of detecting both BSA-conjugated toxins (inhibitory concentration (IC)(50): 4-5 microg/ml). Free toxins were also detectable by competitive immunoassay, whereby 10 microg/ml free gliotoxin (30 microM) and helvolic acid (17 microM), respectively, inhibited antibody binding to cognate toxin-BSA previously immobilised on microwells. This work confirms that sensitive and specific antisera can be raised against fungal toxins and may have an application in diagnosing fungal infection.

Animals↗
PubMed2004

Correlation between gliotoxin production and virulence of Aspergillus fumigatus in Galleria mellonella.

Aspergillus fumigatus is a pathogenic fungus capable of causing both allergic lung disease and invasive aspergillosis, a serious, life-threatening condition in neutropenic patients. Aspergilli express an array of mycotoxins and enzymes which may facilitate fungal colonisation of host tissue. In this study we investigated the possibility of using the insect, Galleria mellonella, for in vivo pathogenicity testing of Aspergillus species. Four clinical isolates of Aspergillus fumigatus and a single strain of Aspergillus niger were characterised for catalase and elastase activity and for the production of gliotoxin. Gliotoxin is an immunosuppressive agent previously implicated in assisting tissue penetration. Results illustrated a strain dependent difference in elastase activity but no significant difference in catalase activity. Gliotoxin production was detected in vitro and in vivo by Reversed Phase-High Performance Liquid Chromatography, with highest amounts being produced by A. fumigatus ATCC 26933 (350 ng/mg hyphae). Survival probability plots (Kaplan-Meier) of experimental groups infected with Aspergillus conidia indicate that G. mellonella is more susceptible to fungal infection by A. fumigatus ATCC 26933, implicating a critical role for gliotoxin production rather than growth rate or enzymatic activity in the virulence of A. fumigatus in this model.

Animals↗
PubMed2003

Isolation and identification of Madurella mycetomatis from two cases of black grain mycetoma in Libya.

Two cases of mycetoma of the foot caused by Madurella mycetomatis are reported in which identification of the etiologic agents was confirmed by culture. A Libyan male aged 40 years and a Chadian female aged 30 years, exhibited eumycetoma of the foot 1 and 2 years, respectively, after a local injury. The diagnoses were based on the clinical presentation and confirmed by mycologic analysis of the grains and culture isolation of the etiologic agent. Prior to this report M. mycetomatis has not been recorded in Libya as a cause of eumycetoma.

Adult↗
PubMed2002

Yeasts of the genus Candida are the dominant cause of onychomycosis in Libyan women but not men: results of a 2-year surveillance study.

BACKGROUND: The reported frequency of recovery of fungi from infected nails varies according to the geographical area. OBJECTIVES: To establish the nature of the causal agents in a sample of the Libyan population presenting with suspected onychomycosis. METHODS: Samples were taken from the infected fingernails of 648 patients attending the Tripoli Medical Centre. RESULTS: Samples from 500 patients proved positive for fungi following culturing, while 476 were potassium hydroxide and culture positive. Of the culture-positive samples, yeasts of the genus Candida (C. albicans, C. parapsilosis, C. glabrata, C. guillermondii and C. tropicalis) were the dominant cause of this condition in women (417 of 434, 96%) but were responsible for only a minority of cases in men (three of 66, 5%). In contrast, dermatophytes (Trichophyton violaceum, T. rubrum, T. mentagrophytes and Microsporum canis) were responsible for this condition in the majority of cases in men (53 of 66, 80%) but only 3% (15 of 434) of cases in women. The mould Aspergillus nidulans was isolated from the nails of 10 (15%) men and two (0.5%) women. CONCLUSIONS: The data obtained in this study reveal an almost total separation of the aetiological agents responsible for onychomycosis based on gender.

Adolescent↗
PubMed2002

Dermatophytes and other fungi associated with skin mycoses in Tripoli, Libya.

This study sought to determine the prevalence of skin infections and their causative agents in the Libyan population. Samples were collected from 2224 patients attending the Dermatology Clinics of the Tripoli Medical Centre (TMC) between August 1997 and December 1999 and were submitted to a mycology laboratory for analysis. Diagnosis was confirmed by microscopic examination in 1180 cases (53.1%) and the causative agent was isolated and cultured in 1160 cases (52.2%). Dermatophytes, Malassezia furfur and Candida albicans were the most common etiological agents isolated. Tinea corporis accounted for 45.9% of cases (85% of cases occurred in children below 15 years of age). The frequency of the other clinical types in descending order was pityriasis versicolor 27.8% (322 cases), candidiosis 13.4% (156 cases), tinea pedis 8.1% (94 cases), tinea manuum 2.6% (30 cases) and tinea barbae 2.2% (26 cases). Trichophyton violaceum was the most common etiological agent, responsible for 44% (300 cases) of dermatophyte infections. Malassezia furfur was ranked the second most frequent causative agent being found in 27.8% of cases, followed by Trichophyton rubrum 13.8% (160 cases) and Candida albicans 10% (116 cases). Other species isolated included Microsporum canis 8.1% (94 cases), Epidermophyton floccosum 6.6% (76 cases) and Trichophyton mentagrophytes 3.1% (36 cases).

Adolescent↗
PubMed2002

Immobilization of Aspergillus fumigatus colonies in a soft agar matrix allows visualization of A549 cell detachment and death.

A model to examine the effects of proliferating Aspergillus fumigatus ATCC 26933 colonies embedded in a thin layer of soft agar on a monolayer of A549 cells was developed and enabled an investigation of the response of cultured cells to fungal growth. This model simulates the conditions on the respiratory surface in patients with invasive aspergillosis and also in the mucus secretions of cystic fibrosis patients with allergic bronchopulmonary aspergillosis. Conidia of A. fumigatus adhering to A549 cells were immobilized in a thin layer of soft agar (0.6% (w/v)) and allowed to germinate at 37 degrees C. Fungal colonies greater than 5 mm in diameter caused rounding-up and detachment of A549 cells underneath the colony and towards the hyphal tips. As the fungal colony diameter increased, cell detachment occurred ahead of the hyphal tips. Cells detached for short periods (less than 6 h) showed no annexin-V (AV) or propidium iodide (PI) staining, suggesting no externalization of phosphatidylserine and an intact plasma membrane. Cells that had detached for periods greater than 6 h were positive for AV and PI indicating the rupture of the plasma membrane and cell death by necrosis. Chemical extraction and separation by thin layer chromatography of agar from zones of cell detachment around fungal colonies revealed the presence of three compounds that may play a role in inducing cell death.

Annexin A5↗
PubMed2001

Baculovirus expression of parvovirus B19 (B19V) NS1: utility in confirming recent infection.

BACKGROUND: The presence of anti-parvovirus B19 (B19V) IgM against viral capsid proteins (VP1 and VP2) has long been used to detect recent infection. The utility of antibodies directed against B19V NS1 protein has received less attention as a serological indicator of recent infection, although anti-B19V NS1 IgG has been associated with persistent infection. OBJECTIVES: To elucidate the role of anti-B19V NS1 antibody detection in recent infection, full-length B19V NS1 was expressed and purified. The resultant antigen was used to develop both Western blot assays and microplate ELISA for the detection of NS1 antibodies. STUDY DESIGN: Serum specimens were obtained from individuals recently infected with B19V (children (n=16), adults (n=40)) and from 17 individuals with no evidence of recent B19V infection. All specimens were screened for anti-B19V NS1 IgG and IgM. RESULTS: It was observed that 68.8% (11/16) of children recently infected with B19V were anti-B19V NS1 IgG seropositive. Furthermore, 27.5% (11/40) anti-B19V VP2 IgM positive specimens also contained anti-B19V NS1 IgM when tested by ELISA, while no reactivity was observed following Western blot analysis, possibly due to the absence of conformational epitopes. CONCLUSIONS: Anti-B19V NS1 IgM detection may have utility in the confirmation of recent infection with B19V.

Adult↗
PubMed2001

Complete heart block and sudden death in mice overexpressing calreticulin.

The expression of calreticulin, a Ca(2+)-binding chaperone of the endoplasmic reticulum, is elevated in the embryonic heart, and because of impaired cardiac development, knockout of the Calreticulin gene is lethal during embryogenesis. The elevated expression is downregulated after birth. Here we have investigated the physiological consequences of continued high expression of calreticulin in the postnatal heart, by producing transgenic mice that overexpress the protein in the heart. These transgenic animals exhibit decreased systolic function and inward I(Ca,L), low levels of connexin43 and connexin40, sinus bradycardia, and prolonged atrioventricular (AV) node conduction followed by complete heart block and sudden death. We conclude that postnatal downregulation of calreticulin is essential in the development of the cardiac conductive system, in particular in the sinus and AV nodes, when an inward Ca(2+) current is required for activation. This work identifies a novel pathway of events, leading to complete heart block and sudden cardiac death, which involves high expression of calreticulin in the heart.

Animals↗
PubMed2001

Pulmonary aspergillosis: clinical presentation, diagnosis and therapy.

Pulmonary aspergillosis is a serious threat to those immunocompromised as a result of disease or therapy, and has been identified as a major cause of morbidity and mortality in asthmatic and cystic fibrosis patients. Pulmonary aspergillosis can occur in three principal forms: saprophytic, allergic and invasive. Saprophytic aspergillosis involves colonisation of the airways, without invasion or damage of viable tissue, and may present as an aspergilloma (fungus ball) consisting of a tangled mass of mycelium, fibrin, inflammatory cells and epithelial-cell debris. Necrotic tissue also may be invaded but usually only in those severely immunocompromised. Allergic aspergillosis is referred to frequently as allergic bronchopulmonary aspergillosis (ABPA), and may occur in approximately 25% of asthmatic and 10% of cystic fibrosis patients. ABPA presents as a non-infectious, potentially fatal inflammatory disease where antigens released by the fungal mycelium provoke an immune response. Invasive aspergillosis is probably the most serious form of the disease and involves the invasion of viable tissue. It occurs predominantly in patients with pre-existing lung damage, and can spread to other organs and distant sites in the body. Aspergillomas may be detected on chest X-ray as spherical-shaped objects, whilst allergic aspergillosis may be visualised by radiological techniques and computed tomography (CT) scan. Surgery may be employed in the case of aspergilloma, and chemotherapy relies upon the use of amphotericin B (liposomal and aerosolised) and itraconazole.

Aspergillosis↗
PubMed2000

Development of an insect model for the in vivo pathogenicity testing of yeasts.

Conventional in vivo assays to determine the relative pathogenicity of yeast isolates rely upon the use of a range of mammalian species. The purpose of the work presented here was to investigate the possibility of using an insect (Galleria mellonella) as a model system for in vivo pathogenicity testing. The haemolymph of G. mellonella larvae was inoculated with PBS containing different concentrations of stationary phase yeasts of the genus Candida by injection at the last pro-leg. Larvae were incubated at 30 degrees C and monitored over 72 hours. Results indicate that G. mellonella can be killed by the pathogenic yeast Candida albicans and by a range of other Candida species but not to a significant extent by the yeast Saccharomyces cerevisiae. The kill kinetics for larvae inoculated with clinical and laboratory isolates of C. albicans indicate the former class of isolates to be more pathogenic. Differences in the relative pathogenicity of a range of Candida species may be distinguished using G. mellonella as a model. This work indicates that G. mellonella may be employed to give results consistent with data previously obtained using mammals in conventional in vivo pathogenicity testing. Larvae of G. mellonella are inexpensive to culture, easy to manipulate and their use may reduce the need to employ mammals for routine in vivo pathogenicity testing with a concomitant reduction in mammalian suffering.

Animals↗
PubMed2000

Adherence mechanisms of Candida albicans.

The yeast Candida albicans is an opportunistic fungal pathogen that is capable of inducing a range of superficial and systemic diseases in the immunocompromised host. Although it displays a variety of virulence factors, one--the ability to adhere to host tissue--is considered essential in the early stages of colonisation and tissue invasion. Adherence is achieved by a combination of specific (ligand-receptor interactions) and non-specific (electrostatic charge, van der Waals forces) mechanisms which allow the yeast to attach to a wide range of tissue types and inanimate surfaces. Conventional methods for treating disease cause by C. albicans rely upon the use of antifungal drugs designed to kill the yeast or arrest its growth. An alternative approach, aimed at disrupting the adherence of the yeast to host tissue in cases of superficial infection, may have potential for controlling disease, particularly in situations where the unattached fungal cell can be removed from the affected site, either by the flushing action of the oropharynx or by the production of mucus in the vagina.

Antifungal Agents↗
PubMed1999

Culture filtrates of Aspergillus fumigatus induce different modes of cell death in human cancer cell lines.

Aspergillus fumigatus culture filtrate (CF) has a potent cytotoxic effect on three human cancer cell lines (DLKP, A549 and HEp-2) and initiates cell death by apoptosis but the execution of the apoptotic process is incomplete. DLKP cells treated with A. fumigatus CF demonstrate features associated with apoptosis but cytoplasmic and nuclear fragmentation were not observed and cells ultimately underwent necrosis. The apoptotic process commenced in A549 and HEp-2 cells upon exposure to CF, cell shrinkage was observed but membrane blebbing and apoptotic body formation were not detected and detached cells died by necrosis. In contrast, extensive nuclear fragmentation and apoptotic body formation were evident in DLKP and A549 cells treated with anti-neoplastic agents. This work indicates that A. fumigatus CF is cytotoxic to cancer cells and can initiate apoptosis but that the complete apoptotic pathway is not followed.

Apoptosis↗
PubMed1999

Connecting and becoming culturally competent: a Lakota example.

Addressing how nurses become culturally competent is essential for knowledge development beyond why sociocultural understandings are important. This article reports participatory research conducted during intercultural immersion learning experiences of non-native nurses on an Indian reservation. Emphasizing collaborative relationships within unfamiliar social, political, and economic circumstances, and using Diekelmann's "concernful practices" as an organizing scheme, prompted participants to explicate practices that promote intercultural connecting. Suggesting integral shifts in value orientations with changes in cultural competence, the findings argue for attending to associations between those dynamics and potential for developing co-responsibility (with consumer groups) for advocating improved health and health care.

Communication↗
PubMed1999

Characterisation of yeasts implicated in vulvovaginal candidosis in Irish women.

High-vaginal swabs were taken from 98 women attending a genitourinary clinic in Dublin city who presented with symptoms of vaginitis. Twenty-eight (28.6%) proved culture-positive for yeasts. Candida albicans was isolated from 26 of the yeast-positive patients and Candida glabrata and Candida tropicalis were isolated from a further two patients. Two patients were colonized by two yeasts simultaneously (C. albicans and Candida lucitaniae, and C. albicans and Candida krusei). Yeasts were characterised on the basis of their adherence ability, extracellular enzyme production and resistance to antifungal agents. All C. albicans isolates demonstrated high adherence abilities to buccal epithelial cells, but produced relatively low levels of phospholipase and acid proteinase. The non-C. albicans isolates demonstrated low levels of adherence, but no extracellular enzyme production was detected. Isolates were most sensitive to the polyenes amphotericin B and nystatin but a large proportion (50%) of C. albicans isolates were resistant to clotrimazole, which is an important agent in the treatment of vulvovaginal candidosis.

Adolescent↗
PubMed1998

Enhancement of chemotherapeutic drug toxicity to human tumour cells in vitro by a subset of non-steroidal anti-inflammatory drugs (NSAIDs).

The effect on cytotoxicity of combining a range of clinically important non-steroidal anti-inflammatory drugs (NSAIDs) with a variety of chemotherapeutic drugs was examined in the human lung cancer cell lines DLKP, A549, COR L23P and COR L23R and in a human leukaemia line HL60/ADR. A specific group of NSAIDs (indomethacin, sulindac, tolmetin, acemetacin, zomepirac and mefenamic acid) all at non-toxic levels, significantly increased the cytotoxicity of the anthracyclines (doxorubicin, daunorubicin and epirubicin), as well as teniposide, VP-16 and vincristine, but not the other vinca alkaloids vinblastine and vinorelbine. A substantial number of other anticancer drugs, including methotrexate, 5-fluorouracil, cytarabine, hydroxyurea, chlorambucil, cyclophosphamide, cisplatin, carboplatin, mitoxantrone, actinomycin D, bleomycin, paclitaxel and camptothecin, were also tested, but displayed no synergy in combination with the NSAIDs. The synergistic effect was concentration dependent. The effect appears to be independent of the cyclo-oxygenase inhibitory ability of the NSAIDs, as (i) the synergistic combination could not be reversed by the addition of prostaglandins D2 or E2; (ii) sulindac sulphone, a metabolite of sulindac that does not inhibit the cyclooxygenase enzyme, was positive in the combination assay: and (iii) many NSAIDs known to be cyclo-oxygenase inhibitors, e.g. meclofenamic acid, diclofenac, naproxen, fenoprofen, phenylbutazone, flufenamic acid, flurbiprofen, ibuprofen and ketoprofen, were inactive in the combination assay. The enhancement of cytotoxicity was observed in a range of drug sensitive tumour cell lines, but did not occur in P-170-overexpressing multidrug resistant cell lines. However, in the HL60/ADR and COR L23R cell lines, in which multidrug resistance is due to overexpression of the multidrug resistance-associated protein MRP, a significant increase in cytotoxicity was observed in the presence of the active NSAIDs. Subsequent Western blot analysis of the drug sensitive parental cell lines, DLKP and A549, revealed that they also expressed MRP and reverse-transcription-polymerase chain reaction studies demonstrated that mRNA for MRP was present in both cell lines. It was found that the positive NSAIDs were among the more potent inhibitors of [3H]-LTC4 transport into inside-out plasma membrane vesicles prepared from MRP-expressing cells, of doxorubicin efflux from preloaded cells and of glutathione-S-transferase activity. The NSAIDs did not enhance cellular sensitivity to radiation. The combination of specific NSAIDs with anticancer drugs reported here may have potential clinical applications, especially in the circumvention of MRP-mediated multidrug resistance.

Adenocarcinoma↗
PubMed1998

Monoclonal antibodies directed against extracellular matrix proteins reduce the adherence of Candida albicans to HEp-2 cells.

The presence of the extracellular matrix (ECM) proteins collagen types I and IV, laminin and fibronectin on the surface of HEp-2 cells was confirmed by flow cytometry using monoclonal antibodies. Monoclonal antibodies directed against these ECM proteins reduced the adherence of C. albicans ATCC 44990 to HEp-2 cells, the greatest reductions being evident in assays which incorporated anti-collagen type IV monoclonal antibody. The ability of sugaramines to inhibit the adherence of C. albicans to a variety of cell types has been demonstrated previously and the most significant reduction in C. albicans-HEp-2 adherence was in assays which incorporated 0.2M galactosamine. The combination of anti-collagen IV monoclonal antibody and galactosamine reduced the adherence of C. albicans to HEp-2 cells by approximately 70% (p < 0.05).

Antibodies, Monoclonal↗
PubMed1996

Self-assessment of tuberculin skin test reactions by New York City firefighters: reliability and cost-effectiveness in an occupational health care setting.

OBJECTIVE: To determine whether self-assessment of purified protein derivative of tuberculin (PPD) skin test reactions, done using a simple two-choice approach, is an effective screening method for tuberculosis. DESIGN: Double-blind comparison between self-assessments and trained professional readings of PPD skin test reactions, done 72 hours after test administration. SETTING: The New York City Fire Department's Bureau of Health Services. PARTICIPANTS: 2011 New York City firefighters and fire officers were given PPD skin tests during a mandatory retraining course. Thirty-seven persons were excluded because of a history of a positive PPD skin test result or a bacille Calmette-Guérin vaccination. All others agreed to participate in testing and self-assessment done using simple written instructions. Self-assessment results were submitted just before trained professional readings were done. MEASUREMENTS: Self-assessments and trained professional readings of PPD skin test reactions. RESULTS: 1833 participants (91%) interpreted their test reactions as flat. Of these interpretations, 1824 (99.5%) matched the professional reading and 9 (0.5%) did not. One hundred seventy-eight participants (9%) interpreted their test reactions as not flat; 136 of these interpretations (76.4%) matched the professional reading and 42 (23.6%) did not (kappa = 0.828; lower 95% confidence limit = 0.790). The predictive value of a negative self-assessment reading was 99.5%, and the specificity was 97.7%. CONCLUSION: In this occupational health care setting, we follow (and recommend to others with similar populations) a tuberculin screening program based on self-assessment. Repeated tests with follow-up are required for all persons who do not report their results. All persons with self-assessments of "not flat" should return for readings by trained professionals, counseling, and treatment.

Adult↗