Biomedical subjects

M A Shikanai-Yasuda

Publications and source records attributed to M A Shikanai-Yasuda.

At least 19 recordsLinked to original sources

PubMed2004

Paracoccidioidomycosis: an epidemiologic survey in a pediatric population from the Brazilian Amazon using skin tests.

Since Paracoccidioides brasiliensis and Histoplasma capsulatum are known to be present in similar environments, there have been many epidemiologic investigations regarding the prevalences of these two organisms. However, cross-reactivity can occur in paracoccidioidin and histoplasmin skin tests, and this usually results in the overestimation of the prevalence of P. brasiliensis. The prevalence of infection with P. brasiliensis was evaluated in a cross-sectional study of 298 asymptomatic school children in the Brazilian Amazon region (Mato Grosso State). In this investigation, the reactivity of children to two different P. brasiliensis antigen preparations, paracoccidioidin and a purified 43-kD glycoprotein (gp43), was compared with or without the co-administration of histoplasmin. In the group of individuals receiving paracoccidioidin who had a positive histoplasmin skin test result, the prevalence of exposure to P. brasiliensis was 44% (16 of 36). This reactivity to P. brasiliensis was significantly higher than that observed in other groups, which ranged from 4% to 6% (P < 5 x 10(-4) for each). Overall prevalence was 4.6% (95% confidence interval = 2.5-7.7%). These data suggest that gp43 provides a better estimate of exposure to P. brasiliensis when the co-administration of histoplasmin is desired.

Adolescent↗

PubMed2003

The role of gallium-67 scan in defining the extent of disease in an endemic deep mycosis, paracoccidioidomycosis: a predominantly multifocal disease.

The tools currently used to evaluate the extent of paracoccidioidomycosis (PCM) may be of limited value in detecting subclinical lesions. The aim of this study was to verify the role of gallium-67 whole-body scan in evaluating the extent of disease of 65 patients with active PCM. The (67)Ga scan findings were compared with the results of clinical evaluation, chest radiography and/or high-resolution computed tomography (CT), abdominal ultrasound (US) or CT, laryngoscopy, CT or magnetic resonance imaging (MRI) of the head, and technetium-99m methylene diphosphonate bone scan, obtained before treatment. Clinically unsuspected lesions were detected by imaging procedures in 21 patients (32%), mainly in the lungs (n=11), adrenals (n=6), and superficial (n=3) and deep lymph nodes (n=14). (67)Ga scan detected 100% of the cases with subclinical involvement in the lungs. Scintigraphy was superior to chest radiography in demonstrating lung disease (94% vs 81%). The lymphatic lesions were demonstrated by (67)Ga scan in all the clinically suspected cases and in nearly all unsuspected cases, and also revealed more extensive involvement than was clinically suspected in many of them. There was good agreement between (67)Ga scan and the other imaging procedures for the initial detection of thoracic and abdominal lymph nodes and bone involvement. (67)Ga imaging detected most cases of laryngopharyngeal disease with active inflammatory lesions found at indirect laryngoscopy. On the other hand, (67)Ga scan failed to demonstrate most of the adrenal and CNS lesions detected by abdominal US/CT and head CT/MRI. In conclusion, (67)Ga imaging is a useful tool for evaluating the location and extent of suspected and unsuspected lesions in PCM. It could serve as a screening method before the use of other diagnostic procedures, particularly in the detection of lung, superficial and deep lymph node and bone involvement.

Adolescent↗

PubMed2002

Chagas' disease.

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Chagas Disease↗

PubMed2002

Randomized trial with itraconazole, ketoconazole and sulfadiazine in paracoccidioidomycosis.

Forty-two patients with active paracoccidioidomycosis were randomized to receive itraconazole (50-100 mg d(-1)), ketoconazole (200-400 mg d(-1)) or sulfadiazine (100-150 mg kg d(-1) up to 6 g d(-1)) for 4-6 months, followed by slow release sulfa until negativity of serological tests. All 14 patients in itraconazole and sulfadiazine groups and 13 in the ketoconazole group showed an adequate clinical response to the chemotherapy. One patient in the latter group showed treatment failure according to clinical and mycological criteria. The test of the hypothesis that the drugs reduced antibody levels up to ten months of treatment showed a p value equal to 0.0001 for itraconazole, 0.017 for ketoconazole and 0.0012 for sulfadiazine; this reduction was similar for the three groups. In this first randomized study for the treatment of paracoccidioidomycosis we could not show superiority of any one regimen over the others in the clinical and serological responses of patients with the moderately severe form of the disease.

Adolescent↗

PubMed2001

Chagas' disease.

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Adult↗

PubMed1999

Chronic pulmonary paracoccidioidomycosis (South American blastomycosis): high-resolution CT findings in 41 patients.

OBJECTIVE: To assess the pulmonary parenchymal findings on high-resolution CT in 41 patients with the chronic form of paracoccidioidomycosis (South American blastomycosis). SUBJECTS AND METHODS: The study included 41 consecutive patients in whom chronic paracoccidioidomycosis had been proven. All patients underwent high-resolution CT (1-mm collimation, high-spatial-frequency reconstruction algorithm) at 12 equally spaced intervals through the chest. The images were analyzed by two radiologists, and each final decision was reached by consensus. RESULTS: Thirty-eight (93%) of the 41 patients had CT scans with abnormal findings. The findings included interlobular septal thickening in 36 patients (88%), 1-25 mm diameter nodules in 34 (83%), peribronchovascular interstitial thickening in 32 (78%), centrilobular opacities in 26 (63%), intralobular lines in 24 (59%), ground-glass opacities in 14 (34%), cavitation in seven (17%), air-space consolidation in five (12%), traction bronchiectasis in 34 (83%), and paracicatricial emphysema in 28 (68%). In approximately 90% of patients, the abnormalities were bilateral and symmetrical and involved all lung zones. CONCLUSION: High-resolution CT findings of paracoccidioidomycosis consist predominantly of interstitial abnormalities and nodules associated with traction bronchiectasis and paracicatricial emphysema in a bilaterally symmetrical distribution.

Adult↗

PubMed1999

Clinical analysis and parasite genetic diversity in human immunodeficiency virus/Chagas' disease coinfections in Brazil.

To evaluate the possible role of parasitemia on Chagas' disease reactivation in Chagas' disease/human immunodeficiency virus (HIV) coinfection cases and the impact of HIV coinfection on Trypanosoma cruzi genetic diversity, 71 patients with Chagas' disease (34 HIV+ and 37 HIV-) were surveyed. Moreover, 92 T. cruzi stocks from 47 chronic chagasic patients (29 HIV+ and 18 HIV-) were isolated and analyzed by multilocus enzyme electrophoresis and a random amplified polymorphic DNA procedure. High parasitemia appeared to play a major role in cases of Chagas' disease reactivation. In HIV+ patients, the genetic diversity and population structure (clonality) of T. cruzi was similar to that previously observed in HIV- patients, which indicates that immunodepression does not modify drastically genotype repartition of the parasite. There was no apparent association between given T. cruzi genotypes and specific clinical forms of Chagas' disease/HIV associations.

Adult↗

PubMed1998

Follow-up of 18 patients with human immunodeficiency virus infection and chronic Chagas' disease, with reactivation of Chagas' disease causing cardiac disease in three patients.

A series of 18 patients with chronic Chagas' disease and human immunodeficiency virus infection were followed up for 2 to 66 months (median, 15.5 months). Artificial xenodiagnosis was positive for 81.3% and natural xenodiagnosis was positive for 81.8% of patients for whom they were performed; 81.8% of 11 patients had medium- or high-level parasitemia. Reactivation of Chagas' disease--direct microscopic examination of blood revealing parasites and, clinically, patients presenting with cardiac disease--occurred in three patients (16.7%). Specific antitrypanosomal treatment with benznidazole was effective in reducing the level of parasitemia and improving the clinical condition in three of the four patients treated.

Adult↗

PubMed1998

Detection of circulating Paracoccidioides brasiliensis antigen in urine of paracoccidioidomycosis patients before and during treatment.

For the diagnosis and follow-up of paracoccidioidomycosis patients undergoing therapy, we evaluated two methods (immunoblotting and competition enzyme immunoassay) for the detection of circulating antigen in urine samples. A complex pattern of reactivity was observed in the immunoblot test. Bands of 70 and 43 kDa were detected more often in urine samples from patients before treatment. The immunoblot method detected gp43 and gp70 separately or concurrently in 11 (91.7%) of 12 patients, whereas the competition enzyme immunoassay detected antigenuria in 9 (75%) of 12 patients. Both tests appeared to be highly specific (100%), considering that neither fraction detectable by immunoblotting was present in urine samples from the control group. gp43 remained present in the urine samples collected during the treatment period, with a significant decrease in reactivity in samples collected during clinical recovery and increased reactivity in samples collected during relapses. Reactivity of some bands was also detected in urine specimens from patients with "apparent cure." The detection of Paracoccidioides brasiliensis antigens in urine appears to be a promising method for diagnosing infection, for evaluating the efficacy of treatment, and for detecting relapse.

Antifungal Agents↗

PubMed1998

Reactivation of Chagas' disease in a human immunodeficiency virus-infected patient leading to severe heart disease with a late positive direct microscopic examination of the blood.

We report a human immunodeficiency virus (HIV)-infected man with chronic Chagas' disease who developed a congestive heart failure that could not be clinically controlled. Endomyocardial biopsy revealed severe myocarditis and the xenodiagnosis result was positive, but Trypanosoma cruzi by direct microscopic examination of the blood was found only four months after the symptoms had started. Treatment with benznidazole was effective in reducing parasitemia, stabilizing the clinical status, and controlling tissue damage related to the parasite. Although the finding of T. cruzi trypomastigotes by direct microscopic examination of the blood has been considered the mark of Chagas' reactivation in immunocompromised patients with chronic disease, in this case it was a late finding.

AIDS-Related Opportunistic Infections↗

PubMed1997

Monocyte adherence to Paracoccidioides brasiliensis, zymosan-C3b and erythrocyte-hemolysin in patients with paracoccidioidomycosis.

Independent and dependent (C3b/Fc receptors) opsonic adherence ability of monocytes from thirty-three patients with acute or chronic paracoccidioidomycosis and from 13 healthy individuals were studied in the presence of Paracoccidioides brasiliensis (Pb), Paracoccidioides brasiliensis opsonized by patient's serum (PbPS) or normal serum (PbNS), zymosan opsonized by fresh sera from healthy donors (ZyNS) and erythrocytes opsonized by hemolysin (EA). Statistically significant differences concerning the percentage of adhered monocytes to PbPS (number of adhered monocytes/total number of monocytes) were detected between control and chronic (active and inactive) groups. Significant differences in relationship to the mean number of PbPS (number of fungi in monocytes/total number of monocytes) were also observed between control and chronic active mycosis. Present data suggest that patients with chronic disease have more ability in the first step of phagocytic activity, considered as the main effector mechanism to control the dissemination and severity of paracoccidiodomycosis.

Acute Disease↗

PubMed1997

Lung tissue mechanics in the early stages of induced paracoccidioidomycosis in rats.

Pulmonary dysfunction represents the most important cause of death in patients with paracoccidioidomycosis (PBM). In order to investigate the functional changes of the lungs in the early stages of PBM, a model of benign disease was developed by intratracheal challenge of 12-week old isogenic Wistar rats with 1 x 10(6) yeast forms of Paracoccidioides brasiliensis. Animals were studied 30 and 60 days after infection, when fully developed granulomas were demonstrable in the lungs. Measurements of airway resistance, lung elastance and tissue hysteresis were made during sinusoidal deformations (100 breaths/min, tidal volume = 2 ml) with direct measurement of alveolar pressure using the alveolar capsule technique. Infection caused a significant increase in hysteresis (infected: 1.69, N = 13; control: 1.13, N = 12, P = 0.024, ANOVA), with no alterations in airway resistance or lung elastance. Histopathological analysis revealed the presence of fully developed granulomas located in the axial compartment of the lung interstitial space. These results suggest that alterations of tissue mechanics represent an early event in experimental PBM.

Animals↗

PubMed1996

Changes in isotype composition and antigen recognition of anti-Trypanosoma cruzi antibodies from acute to chronic Chagas disease.

This report describes differences in humoral immune response of acute and chronic phases of human Chagas disease. The reactivities of IgG, IgM, and IgA anti-Trypanosoma cruzi antibodies in serum samples from both groups of patients were compared by enzyme-linked immunosorbent assay (ELISA) employing either one of four antigenic fractions: mouse laminin (LAM), which reacts through Gal alpha 1-3Gal epitopes expressed on trypomastigote surface: whole intact trypomastigotes (TCT); trypomastigotes excreted/secreted antigens (TESA); and epimastigote alkaline extract (EAE). The selection of T. cruzi antigen preparations was based on their relative content of surface and internal antigens found in trypomastigote forms. The proportion of IgG reactive to carbohydrate epitopes was assessed through the decay of IgG reactivity from acute and chronic sera after m-periodate oxidation of solid-phase bound antigens. Trypomastigote and TESA antigens recognized by IgG from acute and chronic sera were also compared by immunoblotting. ELISA and immunoblotting data showed that: (1) the proportion of IgG directed to trypomastigote surface antigens was higher in acute than in chronic sera, whereas the opposite was found for internal antigens, (2) acute sera contained a higher percentage of IgG reactive to trypomastigote carbohydrate epitopes than chronic sera, and (3) anti-T. cruzi IgA was found exclusively in acute sera and led to 100% positivity when LAM, TCT, and TESA were employed as antigens. IgA ELISA with these antigens and IgG immunoblotting pattern with TESA could be useful as serological markers for the acute phase of human Chagas disease.

Animals↗

PubMed1996

Cryptococcosis as an opportunistic infection in immunodeficiency secondary to paracoccidioidomycosis.

We describe the case reports of two patients with immunodeficiency secondary to paracoccidioidomycosis (PCM) and opportunistic Cryptococcus neoformans infections. Secondary immunodeficiency likely occurred as a consequence of the intestinal loss of proteins and lymphocytes associated with malabsorption syndrome due to obstructed lymphatic drainage. Both patients had had severe abdominal involvement during the acute PCM disease. Immunological evaluation showed cellular and humoral immunity impairment. Cryptococcosis manifested as relatively well circumscribed lesions: osteolytic lesions of the skull in one patient, and pulmonary nodules in the other. The latter was treated surgically and with amphotericin B, whereas the other was treated with the combination amphotericin-B and flucytosine. Both patients had a good response to treatment with complete regression of the lesions. They have now 2 and 4 years of follow-up with maintenance therapy and no indication of reactivation of the infection. PCM also did not reactivate. The clinical and immunological characteristics of these patients are discussed and compared to the opportunistic C. neoformans infections of AIDS and transplant patients.

Adult↗

PubMed1996

Antigen-specific immunosuppression in paracoccidioidomycosis.

To characterize the immune dysfunction associated with paracoccidioidomycosis, we studied the in vitro lymphocyte reactivity to phytohemagglutinin (PHA), pokeweed mitogen (PWM), a Candida albicans antigen (CMA), and a Paracoccidioides brasiliensis antigen (PbAg) in 32 patients with the acute and the chronic form of the disease before or during the initial phase of treatment and after clinical cure. We also studied, as controls, 30 healthy individuals, 15 of them immune to P. brasiliensis. Results showed a strong hyporesponsiveness to the PbAg while responses to mitogens and CMA were comparable with those of controls. Patients with the acute form of the disease (usually more severe) had more marked PbAg hyporesponsiveness than those with the chronic form. After patients' clinical cure, PbAg proliferative responses were similar to controls and greater than those seen before pretreatment. Changes in other parameters were also seen in the treated patients; skin test anergy to paracoccidioidin, high levels of anti-P. brasiliensis antibodies, leukocytosis, and eosinophilia. These changes were usually more intense in patients with the acute form of the disease. The post-treatment CD4+, CD8+, and total lymphocyte counts were similar to those of controls. Correlation between these parameters and the lymphoproliferative responses to the various stimuli was only found with PbAg: PbAg responses correlated inversely with eosinophil and anti P. brasiliensis antibody levels. Overall, our results demonstrate an antigen-specific-cellular immunity defect, which is reversible with treatment and possibly related to a T helper cell-2 pattern of immune response during active disease.

Adolescent↗

PubMed1995

Polyserositis in a patient with acute paracoccidioidomycosis and hepatosplenic schistosomiasis.

A severe case of juvenile paracoccidioidomycosis (PCM), manifested as cholestatic jaundice, lymph node enlargement and an unusual form of polyserositis, associated with portal hypertension secondary to schistosomiasis, as well as bacteremias caused by E. coli and S. aureus and post-transfusional hepatitis C is reported. Temporary unresponsiveness of in vivo and in vitro cellular immune responses to P. brasiliensis were registered. The authors discuss the possible interference of either agent in the host immune response, thus explaining the severity of PCM in the present case.

Acute Disease↗

PubMed1993

Trypanosoma cruzi: detection of a circulating antigen in urine of chagasic patients sharing common epitopes with an immunodominant repetitive antigen.

A monospecific antiserum raised to a Trypanosoma cruzi recombinant antigen, with tandem repeat of 68 amino acids, was used to screen urine samples of chagasic and nonchagasic patients. The antiserum detected a specific 150-160 kDa antigen in urine of 60% of chronic chagasic patients, but not in urine samples from nonchagasic patients and healthy control individuals. The reactivity to 150-160 kDa urinary antigen could be abolished by adsorption with the recombinant repetitive antigen. These results suggest that 150-160 kDa urinary antigen is a T. cruzi-derived antigen and specific for Chagas' disease.

Adult↗

PubMed1993

Magnetic resonance imaging in intracranial paracoccidioidomycosis.

Paracoccidioidomycosis is a systemic mycosis, endemic in South and Central America, that affects the central nervous system (CNS) in almost 10% of patients. Neurological involvement includes two different clinical forms: meningeal and granulomatous, also known as the pseudotumor form. Five patients with biopsy-proved systemic paracoccidioidomycosis and neurological complaints were studied by magnetic resonance imaging. CNS involvement was detected in all patients in the form of multiple round or lobulated lesions, predominantly hypointense on T2-weighted images and ring or nodular enhancement on post-gadolinium T1-weighted images. The lesions were distributed diffusely, with a slight predominance in the supratentorial compartment, although infratentorial lesions were also observed, mainly in the cerebellum. Hypointense lesions on T2-weighted images persisted in all 3 patients reexamined after treatment, whereas enhancing lesions on post-gadolinium T1-weighted images turned isointense in 2 patients. Magnetic resonance imaging is a sensitive method in documenting CNS paracoccidioidomycosis, most frequently as supratentorial and infratentorial multiple, round or lobulated hypointense lesions on T2-weighted images.

Adult↗