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Biomedical subjects

M I Duarte

Publications and source records attributed to M I Duarte.

At least 19 recordsLinked to original sources
PubMed2000

Involvement of the pancreas in AIDS: a prospective study of 109 post-mortems.

BACKGROUND: Pancreatic involvement in AIDS is rarely mentioned in medical literature. AIMS: To identify the main morphological patterns of the pancreas using optical and electron microscopy in AIDS patients. DESIGN: An open, prospective, and sequential study in a tertiary institutional hospital. METHODS: Consecutive post-mortems of 109 AIDS patients and 38 controls (1995). Baseline characteristics of AIDS patients and controls were evaluated. Morphological analysis consisted of: (i) semi-quantitative score of acinar and parenchymal elements; (ii) qualitative analysis of ducts, vascular components, nerves, and Langerhans' islets; (iii) specific stains and immunohistochemistry for opportunistic agents; (iv) ultrastructural data. RESULTS: The mean age of AIDS patients was 37 years; 80% were male; 60% were white; 21% were alcoholic. All patients with AIDS had normal blood amylase, blood glucose, and pancreatic ultrasound. Histological findings were: acinar atrophy (60%), few zymogen granula in acinar cytoplasm (52%), abnormalities in acinar nucleus (65%), pancreatic steatosis (66%), and focal necrosis (17%). Immunohistochemistry revealed: mycobacteriosis (22%), toxoplasmosis (13%), cytomegalovirus (9%), Pneumocystis carinii (9%), and HIV p24 antigen in macrophage cytoplasm (22%). Ultrastructural examination showed: decreased zymogen granula, enlargement and proliferation of the endoplasmic reticulum and mitochondria, nuclear abnormalities, and increased lipid droplets in acinar cytoplasm. CONCLUSION: Pancreatic involvement in AIDS is very frequent (90%) and is usually asymptomatic. Morphological changes showed three patterns of pancreatic alterations: 'nutritional-like', inflammatory and both of these together. The 'nutritional-like' pattern (atrophy, few zymogen granula and steatosis) may be due to many factors such as nutritional characteristics (Kwashiorkor-like) induced by the HIV infection or related to the HIV virus itself.

AIDS-Related Opportunistic Infections↗
PubMed2000

Use of itraconazole in the treatment of mucocutaneous leishmaniasis: a pilot study.

OBJECTIVE: Mucocutaneous leishmaniasis is widely distributed in Brazil, with Leishmania (Viannia) braziliensis being the major etiologic agent. The currently recommended therapy is limited by its parenteral use, high toxicity, and variable efficacy. A clinical pilot study was conducted to analyze itraconazole as an oral alternative for the treatment of mucocutaneous leishmaniasis. METHODS: Ten patients were enrolled to receive 4 mg/kg per day (up to 400 mg/d) itraconazole for 6 weeks on an outpatient regimen. Diagnosis was based on clinical otorhinolaryngologic examination, followed by a specific serologic reaction, the Montenegro test and pathologic analysis with immunohistochemical reaction. Healing of the lesions was confirmed by clinical otorhinolaryngologic examination. Side effects were monitored by general clinical assessment, hemoglobin determination, leukocyte counts, and liver function tests, all performed before, during, and 1 month after the end of treatment. RESULTS: Six of 10 patients presented healed lesions 3 months after treatment, with a sustained therapeutic response for at least a median period of 14.5 months (range, 12-18 mo). Side effects were not observed. CONCLUSIONS: This pilot study demonstrated that itraconazole can be an effective and well-tolerated alternative for the treatment of mucocutaneous leishmaniasis. Further randomized studies and double blind controlled trials are needed to assess the benefits of this drug in the treatment of mucocutaneous leishmaniasis.

Adult↗
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↗
PubMed1997

Lung lesions in human leptospirosis: microscopic, immunohistochemical, and ultrastructural features related to thrombocytopenia.

Lung fragments from 12 patients were collected immediately after death and studied by light and electron microscopy and by immunohistochemistry to describe the main morphologic and ultrastructural aspects of the lung and platelets in leptospirosis (Weil's syndrome), to search for the possibility of disseminated intravascular coagulation (DIC), and to assess the relationship between endothelial lesions and local platelet aggregation and the leptospiral antigen distribution, as well as its relationship with the intensity of the lesions. The immunohistochemical results for fibrin aggregates were positive in the lumen and/or on the vascular endothelium in nine cases and on the alveolar surface in seven cases, leading to the diagnosis of the adult respiratory distress syndrome in these seven cases. Test results for leptospiral antigen by immunohistochemistry were positive in eight cases with no direct relationship between antigen deposits in the pulmonary vascular endothelium and intensity of the lesions. The ultrastructural findings were uniform and constant. Capillary lesions were characterized by swelling of endothelial cells, an increase in pinocytotic vesicles, and giant dense bodies in the cytoplasm of these cells. No necrosis, rupture, nor exposed subendothelial collagen was observed outside the hemorrhagic areas, and the intercellular junctions were preserved. The lung involvement in severe human leptospirosis presents as hemorrhagic pneumopathy with septal capillary lesions that are the usual cause of death. The thrombocytopenia that was verified in 11 of 12 patients in our study seems to bear no relationship to DIC and seems to be determined by activation, adhesion, and aggregation of platelets to the stimulated vascular endothelium, with an amorphous electron-dense substance between the endothelial cells and the adherent platelets in places where the subendothelial collagen was not exposed.

Adult↗
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↗
PubMed1995

Simultaneous occurrence of acute myocarditis and reactivated Chagas' disease in a patient with AIDS.

Myocarditis is not an uncommon finding in autopsy series of patients with AIDS, although clinically important myocarditis is rarely noted. We describe a 50-year-old woman with AIDS and chronic chagasic megaesophagus, without previous cardiac abnormalities, who experienced reactivation of Chagas' disease, characterized by the finding of Trypanosoma cruzi via direct microscopic examination of the buffy coat, xenodiagnosis, and blood culture; she developed fatal acute myocarditis. Reactivation of Chagas' disease in patients with AIDS has been reported, but in the great majority of cases it has been associated with central nervous system involvement. In areas where Chagas' disease is endemic, reactivation may occur in patients with AIDS.

AIDS-Related Opportunistic Infections↗
PubMed1993

Regression of diffuse intralobular liver fibrosis associated with visceral leishmaniasis.

Diffuse intralobular fibrosis of the liver is rare in cases of New World visceral leishmaniasis. A patient with this disease from a newly endemic area in the northernmost area of the Brazilian Amazon region was studied. Hypertrophy and hyperplasia of the phagocytic mononuclear cell system were observed, with parasitism and Disse's space fibrosis diffusely involving the liver. This description is based on a biopsy carried out after seven days of treatment with Glucantime. Another biopsy performed almost two years later showed no fibrosis, no Kupffer cell hypertrophy and hyperplasia, and no parasitism. The mechanism of fibrosis and regression is discussed.

Adolescent↗
PubMed1992

Histopathology of lymphoid organs in experimental leishmaniasis.

Hamsters (Mesocricetus auratus) were inoculated with L. (L.) chagasi and killed on days 7, 15, 30, 45 and 60 after infection. The lymphoid organs developed initial proliferation of the B lymphocyte zone with recovery by the 60th day group when pyroninophilic cells were prominent. The T lymphocyte area showed a progressive selective decrease of lymphocytes and cellular density with cellular pleomorphism including macrophages, plasma cells and reticular cells. The mean volume of the white pulp increased with the lymphoid follicle hyperplasia but returned to its initial level by day 60. The main red pulp change was marked hyperplasia of the phagocytic mononuclear cells containing parasites from the 30th day of infection onward. These changes are compatible with the humoral and cellular immunoresponse found in patients with visceral leishmaniasis (VL).

Animals↗
PubMed1991

Comparative and sequential histopathology of Plasmodium chabaudi-infected Balb/c mice.

1. Rodent experimental models have been useful to study severe malaria but few serial and controlled studies have been conducted. In the present investigation, we describe the histopathology of lethal and non-lethal rodent malaria induced by Plasmodium berghei and P. chabaudi. P. berghei malaria shows a uniformly lethal course, while P. chabaudi malaria produces a non-lethal acute infection with recovery and periodical recrudescences. Sequential histopathological changes were also characterized in P. chabaudi malaria to determine the evolution of the lesions. 2. P. berghei-infected mice have a more severe organ involvement and lower blood regenerative changes than P. chabaudi-infected mice. Two patterns of organ involvement were observed by comparing the two infections. The first is related to nonspecific parasitized red blood cell clearance by liver and spleen. The second is related to specific changes due to a specific parasite strain interaction with the host, such as those found in the lungs. 3. Sequential changes in P. chabaudi-infected mice were characterized by perihepatocytic reticulin fiber deposition during the recovery from infection, which faded in subsequent stages. Other organs had a similar regressive evolution, except splenic lymphoid tissue which underwent histological restoration or even hypertrophy after depletion in the acute stage. No brain or heart lesions were observed in either model during the acute and subsequent stages. 4. P. chabaudi infection, whose histopathology is described here for the first time, should be useful as a non-lethal experimental model to study the evolution of histopathological alterations in malaria.

Animals↗
PubMed1990

Experimental visceral leishmaniasis: sequential events of granuloma formation at subcutaneous inoculation site.

Hamsters were inoculated with IO7 Leishmania (Leishmania) chagasi amastigotes in the hind footpads and killed at 7, 15, 30, 45, 60, 75 and 90 days after infection. We observed mononuclear inflammatory infiltrates with many parasites on the 7th and 15th days of infection. On the 30th day there was early granuloma formation. After 45 days the lesion was characterized by well defined epithelioid granuloma with multinuclear giant cells whose cytoplasm showed Schaumann bodies. Non-particulate antigenic material was present in the macrophage cytoplasm and between the lamellae of the Schaumann bodies. Granuloma formation has an important role for the control of infection at the inoculation site. The results indicate that dissemination of the infection must occur in the first 45 days, before granuloma formation has taken place.

Animals↗
PubMed1989

Liver parenchymal cell parasitism in human visceral leishmaniasis.

Liver parenchymal cell parasitism with the amastigotes form of L. donovani was detected by electron microscopy in human visceral leishmaniasis. Endocytosis was considered to be the mechanism by which the leishmania entered the cell. Evidence of well preserved parasites within hepatocytes suggest this parasitism as a possible reservoir for recrudescence.

Humans↗
PubMed1989

Cytoadherence in human falciparum malaria as a cause of respiratory distress.

The ultrastructure of three cases of fatal human falciparum malaria was studied in order to identify the cytoadherence of the endothelial cells in relation to parasitized red blood cells and septal interstitial changes which could be related to respiratory distress. Two cases showed marked endothelial oedema narrowing the capillary lumen with areas of adherence preferentially related to knobs, accompanied by septal interstitial oedema. One case showed no endothelial cells oedema, no knobs in parasitized red blood cells with no cytoadherence, no septal interstitial oedema and no respiratory distress. Cytoadherence seems to be the mechanism responsible for the septal pulmonary changes in severe falciparum malaria.

Animals↗
PubMed1989

Baseline volume data of human liver parenchymal cell.

Normal human liver fragments obtained through intra surgical needle biopsies from five selected hospital cases were fixed in glutaraldehyde and subsequently in osmium tetroxide and embedded in Araldite. These samples were studied in semithin sections under light microscopy. Stereological methods applied on photomicrographs were used to estimate the hepatocyte nuclear volume, the nuclear and cytoplasmic volume densities as well as the hepatocyte numerical density in the liver intermediate lobular zone. The average absolute volume of the mean hepatocyte in the intermediate lobular zone is 2850 +/- 99.9 microns 3. In one cubic centimeter of this zone there are 233 x 10(6) +/- 81.57 parenchymal cells.

Biopsy, Needle↗