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J I Figueroa

Publications and source records attributed to J I Figueroa.

15 recordsLinked to original sources
PubMed2003

Improving malaria surveillance in inner city London: is there a need for targeted intervention?

Malaria in south east London is under-notified, and a previous local study has described how available data can underestimate the incidence. An active surveillance system was established and data on malaria cases diagnosed between the 1st January and 31st December 2000 were gathered from local laboratories, the Malaria Reference Laboratory (MRL) and a neighbouring health authority. In total 320 cases were identified in local residents (42.33 per 100,000). Of these 320, 293 were laboratory confirmed (38.75 per 100,000) and there were 47 notifications on clinical suspicion. Only 6.8% (20) laboratory-confirmed cases were formally notified. Males of African descent aged 25-39 years who travelled to West Africa were most affected, and 92.5% of the cases were of P. falciparum infection. The surveillance programme confirmed that formal malaria notifications are unreliable. The most important group of residents for targeted health intervention are members of ethnic minority groups, born in endemic areas and travelling to their countries of origin to visit family or friends.

Adolescent↗
PubMed1999

Detection of the 70-kilodalton histoplasma capsulatum antigen in serum of histoplasmosis patients: correlation between antigenemia and therapy during follow-up.

Histoplasmosis is an important systemic fungal infection, particularly among immunocompromised individuals, who may develop a progressive disseminated form which is often fatal if it is untreated. In such patients, the detection of antibody responses for both diagnosis and follow-up may be of limited use, whereas the detection of Histoplasma capsulatum var. capsulatum antigens may provide a more practical approach. We have recently described an inhibition enzyme-linked immunosorbent assay (ELISA) for the detection in patients' sera of a 69- to 70-kDa H. capsulatum var. capsulatum-specific antigen which appears to be useful in diagnosis. To investigate its potential for the follow-up of histoplasmosis patients during treatment, antigen titers in the sera of 16 patients presenting with different clinical forms of histoplasmosis were monitored at regular intervals for up to 80 weeks. Sera from four of five patients with the acute form of the disease showed rapid falls in antigenemia, becoming antigen negative by week 14 (range, weeks 10 to 16). Sera from four patients with disseminated histoplasmosis showed falls in antigen levels; three of them became antigen negative by week 32; the fourth patient became negative by week 48. In contrast, antigen titers in four of six AIDS patients with the disseminated form of the disease remained positive throughout follow-up. Sera from only one patient who presented with the chronic form of the disease were analyzed, and this individual's serum became antigen negative by week 9. The inhibition ELISA is shown to be of particular use in the monitoring of non-AIDS patients with the acute and disseminated forms of the disease and may complement existing means of follow-up.

AIDS-Related Opportunistic Infections↗
PubMed1999

Production of specific monoclonal antibodies to Aspergillus species and their use in immunohistochemical identification of aspergillosis.

Two anti-Aspergillus murine monoclonal antibodies (MAbs), designated 164G and 611F, have been produced; both specifically recognize cytoplasmic antigens of A. fumigatus, A. flavus, and A. niger by enzyme-linked immunosorbent assay. The MAbs can identify Aspergillus spp. both in frozen sections by immunofluorescence and in paraffin-embedded clinical specimens by immunofluorescence and immunoperoxidase staining.

Animals↗
PubMed1998

Dermatology in southwestern Ethiopia: rationale for a community approach.

BACKGROUND: Skin diseases represent one of the most frequent causes of morbidity in developing countries; however, little is known about the dermatologic needs of the population. The prevalence of skin disease in two different rural communities in southwestern Ethiopia was determined using descriptive epidemiologic techniques. METHODS: A household survey, designed to ascertain demographic information and dermatologic needs, was given to all households in both communities (827). The point prevalence of skin diseases was determined after examination by dermatologists of 768 self-selected individuals (40% of individuals were invited to attend dermatologic examination, either those self-reporting skin disease or identified as positive cases during the household survey); an individual survey form was given to all of these patients. RESULTS: Although 47% (S/UO) and 59% (Kishe) of the households in the two communities reported skin symptoms, the true dermatologic needs of these settlements were far greater than the expressed values, as examination by dermatologists of randomly selected households revealed that 67% of householders not reporting dermatoses had significant skin disease. During the point prevalence study, the commonest complaints were parasitic (scabies, pediculosis, and onchocerciasis) infestations (46% of diagnoses), followed by bacterial and fungal infections (33%); other conditions included endemic nonfilarial elephantiasis. Overcrowding was the main risk factor for infection. Thirty-two per cent (S/UO) and 39% (Kishe) of examined individuals had received previous treatments, which were ineffective in 74% and 63% respectively. CONCLUSIONS: Subsistence farmers spend a high proportion of their limited cash income on ineffective treatment. Simple schemes of management for the most common dermatoses, which local health workers could be trained to recognize and manage, could do much to redress the burden of skin disease in this population.

Adolescent↗
PubMed1998

Antigenemia in patients with paracoccidioidomycosis: detection of the 87-kilodalton determinant during and after antifungal therapy.

Serological diagnosis and follow-up of paracoccidioidomycosis (PCM) patients have relied mainly on the detection of antibody responses by using techniques such as complement fixation (CF) and immunodiffusion. We recently described a novel inhibition enzyme-linked immunosorbent assay (inh-ELISA) which proved to be useful in the diagnosis of PCM via the detection of an 87-kDa determinant in patient sera (B. L. Gomez, J. I. Figueroa, A. J. Hamilton, B. Ortiz, M. A. Robledo, R. J. Hay, and A. Restrepo, J. Clin. Microbiol. 35:3278-3283, 1997). This test has now been assessed as a means of following up PCM patients. A total of 24 PCM patients, classified according to their clinical presentation (6 with the acute form of the disease, of whom two had AIDS, 12 with the multifocal form of the disease, and 6 with the unifocal form of the disease), were studied. The four human immunodeficiency virus-negative patients with acute PCM showed a statistically significant decrease in circulating antigen levels after the start of antifungal therapy. Antigen levels in this group became negative by our criteria (</=2.3 microgram/ml) before week 20 and remained so in three of four of these patients. In contrast, the two AIDS patients who also presented with the acute form of PCM showed no statistically significant decrease in circulating antigen levels even after 68 weeks of therapy. Taken together as a group, the patients with the multifocal form showed a statistically significant decrease in antigenemia after 28 weeks of therapy. In addition, five of six patients with the unifocal form became antigen negative by week 40. Antigen level decrease mirrored clinical cure in the majority of patients in all clinical groups; in contrast, measurement of anti-PCM antibodies via the CF test showed wide fluctuations in titers during the follow-up period. The inh-ELISA for the detection of the 87-kDa Paracoccidioides brasiliensis determinant would appear to be a valuable additional tool in the follow-up of PCM patients.

AIDS-Related Opportunistic Infections↗
PubMed1997

Tinea capitis in south-western Ethiopia: a study of risk factors for infection and carriage.

BACKGROUND: Tinea capitis is a common dermatophyte infection which constitutes an important public health problem among children worldwide. The endemic nature of scalp ringworm in Africa is perpetuated mainly by the lack of knowledge about the prevalence and carrier status, and the absence of control measures. METHODS: Two hundred and nineteen schoolchildren from urban and rural communities of the Illubabor district, south-western Ethiopia, were examined, and scalp samples were taken. Children were classified according to clinical signs and mycologic findings. RESULTS: Physical examination revealed that 29% of the children had clinical lesions compatible with tinea capitis. Dermatophytes were isolated from 33% of the children's scalp samples; of these, 16% had clinical lesions and 17% were identified as carriers. Trichophyton violaceum was responsible for 97% of infections. CONCLUSIONS: Tinea capitis was the second most prevalent cutaneous finding in these children, with a higher prevalence in the urban community; the predictive value of the clinical diagnosis was low and a high proportion of children were identified as carriers in these communities. No relationship between household overcrowding and scalp infection was found.

Adolescent↗
PubMed1997

Recognition of cytoplasmic yeast antigens of Cryptococcus neoformans var. neoformans and Cryptococcus neoformans var. gattii by immune human sera.

The humoral immune response of patients infected with Cryptococcus neoformans var. neoformans and C. neoformans var. gattii to cytoplasmic (non-capsular) antigens from the two varieties of Cryptococcus has been investigated. Cytoplasmic antigens from C. neoformans (one clinical isolate and one acapsular mutant of var. neoformans and two clinical isolates from var. gattii) were subject to isoelectric focusing, SDS-PAGE and Western blotting; patients sera was then used in the immunoenzyme development of the Western blots. The humoral response from the 20 patients (all HIV+) infected with var. neoformans against the var. neoformans antigens was predominantly IgG based, with a large number of bands recognised: the most commonly recognised bands were at 26, 52, 74, 100, 115 and 144 kDa. The IgM response was less pronounced and the IgA response was practically non-existent. The humoral response of the sera from the 15 patients (all but one HIV-) infected with var. gattii against var. gattii antigens was also predominantly IgG based with bands at 37, 55, 65, 74, 94 and 115 kDa being most commonly recognised. Periodate treatment of cytoplasmic antigens reduced the intensity of antigen recognition, though it did not absolutely destroy reactivity to any individual antigen. Comparison of immunodevelopment of cytoplasmic antigens from both varieties grown at 25 degrees C and 37 degrees C revealed that culture temperature made no differences in the number of bands recognised although there were differences in the intensity of recognition. This is the first report on the pattern of serological recognition of the non-capsular antigens from the two varieties of Cryptococcus and it identifies a number of major antigenic components.

Antibodies, Fungal↗
PubMed1997

Development of a novel antigen detection test for histoplasmosis.

Histoplasmosis is an important systemic fungal infection, particularly among immunocompromised individuals living or travelling in areas of endemicity, who, without antifungal therapy, may develop a progressive disseminated fatal infection. For such patients, the detection of antibody responses by immunodiffusion or complement fixation test is of limited use. In contrast, the detection of Histoplasma capsulatum circulating antigens may provide a more practical approach to the rapid diagnosis of the disease. Accordingly, an inhibition enzyme-linked immunosorbent assay (ELISA) for the detection of a 69- to 70-kDa H. capsulatum-specific determinant and incorporating a species-specific murine monoclonal antibody was developed. With sera from patients with different forms of the disease (n = 35), the overall sensitivity of the test was found to be 71.4%, while the specificity was found to be 98% with normal human sera from areas of endemicity (n = 44) and 85.4% with sera from patients with other chronic fungal or bacterial infections (n = 48). This novel, highly specific ELISA provides a significant addition to the existing diagnostic tests for the detection of histoplasmosis.

Adolescent↗
PubMed1997

Use of monoclonal antibodies in diagnosis of paracoccidioidomycosis: new strategies for detection of circulating antigens.

The precise diagnosis of paracoccidioidomycosis, in most cases, is established by direct methods and indirect immunological tests. The latter method is reliant on the identification of the host's humoral responses, which are usually impaired or absent in patients with severe juvenile forms of the disease and in immunocompromised patients. Determining disease activity or assessing treatment responses by measuring antibody levels is difficult, since antibody titer may remain elevated or persist at stationary levels, even in the presence of clinical improvement. Consequently, there is a need for alternative tests aimed at the identification of circulating antigens. A modification of the standard hybridoma production method was used to raise a panel of murine monoclonal antibodies (MAbs) against the yeast form of Paracoccidioides brasiliensis. Of these, MAb PIB, directed against an 87-kDa determinant, was used to develop an inhibition ELISA (inh-ELISA) capable of detecting as little as 5.8 ng of circulating antigen per ml of serum. Sera from 46 patients with paracoccidioidomycosis or other mycoses and sera from healthy individuals were evaluated by the inh-ELISA; overall sensitivity was 80.4% (37 of 46 paracoccidioidomycosis patients tested positive), and specificity compared with that of normal controls from areas of endemicity was 81.4%. The inh-ELISA detected circulating antigen in 100% of patients with the acute form of paracoccidioidomycosis and in 83.3 and 60% of patients with the chronic multifocal and unifocal forms of paracoccidioidomycosis according to the patients' clinical presentation. These results indicate that the inh-ELISA with MAb PIB is effective in the detection of circulating antigen and that this test may be useful for monitoring responses to treatment and establishing disease prognoses.

Antibodies, Fungal↗
PubMed1994

Immunohistochemical detection of a novel 22- to 25-kilodalton glycoprotein of Paracoccidioides brasiliensis in biopsy material and partial characterization by using species-specific monoclonal antibodies.

Two murine monoclonal antibodies (MAbs) specific to Paracoccidioides brasiliensis (as determined by enzyme-linked immunosorbent assay [ELISA] and Western blot [immunoblot]) were produced by using a modification of standard hybridization protocols, with cyclophosphamide included as an immunomodulator to abolish responses to highly cross-reactive immunodominant epitopes. MAbs PS14 and PS15 are two different clones which exhibit similar characteristics by ELISA and Western blot. They are directed against a 22- to 25-kDa antigen which is present in P. brasiliensis and which could not be identified in other dimorphic fungi by ELISA or Western blot. Partial purification of the antigen was accomplished by isoelectric focusing, and deglycosylation studies suggested that the 22- to 25-kDa antigen is a glycoprotein with a pI of between 4.5 and 5 and that O-linked sugars may be part of the recognized epitope. The MAbs stained the cytoplasm of P. brasiliensis yeast and hyphal cells in cryostat sections of fresh cultures of the fungus. In addition, the MAbs stained the wall of paracoccidioidomycotic granulomas, as well as the cytoplasm of the fungus, as determined by the use of immunofluorescence, immunoperoxidase, and immuno-alkaline phosphatase staining techniques in paraffin-embedded sections of human biopsy material, and they failed to stain granulomas resulting from other clinical conditions. These findings suggest that these MAbs have potential use in the immunohistochemical identification of P. brasiliensis.

Adrenal Glands↗
PubMed1990

Preparation of species-specific murine monoclonal antibodies against the yeast phase of Paracoccidioides brasiliensis.

A panel of four murine monoclonal antibodies showing species specificity for the yeast phase of the pathogenic dimorphic fungus Paracoccidioides brasiliensis was produced by using a modification of the standard monoclonal antibody technology. This involved the use of the immunosuppressive drug cyclophosphamide to suppress the immune response of test animals to fungi showing cross-reactivity, i.e., to Histoplasma capsulatum. One monoclonal antibody, P4, which had a high titer by enzyme-linked immunosorbent assay, was shown to recognize a linear antigenic epitope of P. brasiliensis at a molecular size of 70,000 to 75,000 daltons by Western blot (immunoblot) analysis. The potential use of these monoclonal antibodies, which are the first species-specific probes to P. brasiliensis that have been produced, in the field of serodiagnosis is discussed.

Animals↗
PubMedDate not supplied

Preparation of murine monoclonal antibodies against the yeast phase of the dimorphic fungus Sporothrix schenckii.

Three murine monoclonal antibodies (Mabs) were raised against a cytoplasmic antigen of the yeast phase of the pathogenic fungus Sporothrix schenckii using a modification of standard hybridoma technology incorporating the immunosuppressive drug cyclophosphamide. When tested for species-specificity within the pathogenic dimorphic fungi one of these Mabs (S5) showed little cross-reactivity by enzyme-linked immunosorbent assay and Western blot, though there was some recognition of Paracoccidioides brasiliensis antigen. This Mab recognized a 70-75 kDa molecule on reduced Western blots of S. schenckii antigen. The other two Mabs (S12 and S15) showed cross-reactivity with all dimorphic fungal antigens tested, though they appeared to recognize a molecule of similar molecular weight. This is the first report of any attempt to raise species-specific Mabs against this important causative agent of dermatological disease.

Animals↗
PubMedDate not supplied

Isolation and partial characterization of a Paracoccidioides brasiliensis 58 kDa extracellular glycoprotein which is recognized by human immune sera.

A novel 58 kDa antigenic determinant of the fungus Paracoccidioides brasiliensis was identified by enzyme-linked immunosorbent assay using a panel of species-specific murine monoclonal antibodies (MAbs). Western immunoblot analysis, deglycosylation studies and isoelectric focusing indicated that this 58 kDa antigen is a glycoprotein, with a pI of approximately 5.2. The molecule was purified from P. brasiliensis culture filtrate and yeast cytoplasmic antigens by membrane ultrafiltration, liquid isoelectric focusing and gel filtration; N-terminal amino acid sequence data revealed no substantial homology with known proteins. The presence of the antigen in the cytoplasm of both yeast and mycelial forms of the fungus was demonstrated when these MAbs were used as markers in immunofluorescence, immunoperoxidase and immunoalkaline phosphatase techniques to label P. brasiliensis in cryostat sections. These MAbs also recognized the cytoplasm of P. brasiliensis yeast forms in paraffin-embedded pathological specimens from human cases. A preparation of the 58 kDa component from yeast cytoplasmic antigen was reacted by Western immunoblotting with 26 different serum samples from paracoccidioidomycosis patients, and 81% of them recognized it.

Adult↗
PubMedDate not supplied

The prevalence of skin disease among school children in rural Ethiopia--a preliminary assessment of dermatologic needs.

It is always assumed that the prevalence of skin diseases in developing countries is very high, and that infestations and skin infections are highly endemic in poor rural communities; however, very few epidemiologic reports verify these assumptions. As part of a continuing study of dermatologic needs in southwestern Ethiopia, and to estimate the prevalence of treatable skin disease in children, a school survey was undertaken in Shebe. In October 1992, 112 children were examined by a team of dermatologists and their conditions were recorded. Twenty-two children (19.6%) were considered healthy and 90 (80.4%) had one or more skin diseases. A total of 140 conditions were identified and considered treatable in 98% of children. Infestations were the most prevalent skin pathology, 81.2%, followed by fungal infections, 13.4%.

Adolescent↗