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Biomedical subjects

A C Monteiro

Publications and source records attributed to A C Monteiro.

12 recordsLinked to original sources
PubMed2001

The protease inhibitor chagasin of Trypanosoma cruzi adopts an immunoglobulin-type fold and may have arisen by horizontal gene transfer.

Chagasin, a protein from Trypanosoma cruzi, is the first member of a new family of tight binding cysteine protease inhibitors [Monteiro, A.C.S., Abrahamson, M., Lima, A.P.C., Vannier-Santos, M.A. and Scharfstein, J. (2001) J. Cell Sci., in press] [corrected]. Despite its lack of significant sequence identity with known proteins, convincing structural models, using variable light chain templates, could be constructed on the basis of threading results. Experimental support for the final structure came from inhibition data for overlapping oligopeptides spanning the chagasin sequence. Chagasin therefore exemplifies a new protease inhibitor structural class and a new natural use for an immunoglobulin-like domain. Limited sequence resemblance suggests that chagasin may represent the result of a rare horizontal gene transfer from host to parasite.

Amino Acid Sequence↗
PubMed2001

On-line mercury and methylmercury pre-concentration by adsorption of their dithiophosphoric acid diacyl ester chelates on a C18 column and cold-vapor atomic-absorption detection.

The pre-concentration of mercury(II) and methylmercury by adsorption of their dithiophosphoric acid diacyl ester (DDTP) chelates on a C18 column, then detection with cold-vapor atomic-absorption spectrometry was investigated. Conditions such as sample pH, reductant and chelating agent flow and concentration, and eluent and carrier gas flow were optimized. Optimization was performed by use of evolutionary operation with a proper factorial design. At a sample flow of 5.3 mL min(-1) and a loading time of 4.5 min, column adsorption efficiency ranged from 88 to 93% for both species. Detection limits down to 10 ng L(-1) were obtained at a sample throughput of 12 h(-1). There was good agreement between found and certified values in the analysis of certified reference materials after their microwave-assisted mineralization with HNO3 and H2O2.

Chelating Agents↗
PubMed2001

Identification, characterization and localization of chagasin, a tight-binding cysteine protease inhibitor in Trypanosoma cruzi.

Lysosomal cysteine proteases from mammalian cells and plants are regulated by endogenous tight-binding inhibitors from the cystatin superfamily. The presence of cystatin-like inhibitors in lower eukaryotes such as protozoan parasites has not yet been demonstrated, although these cells express large quantities of cysteine proteases and may also count on endogenous inhibitors to regulate cellular proteolysis. Trypanosoma cruzi, the causative agent of Chagas' heart disease, is a relevant model to explore this possibility because these intracellular parasites rely on their major lysosomal cysteine protease (cruzipain) to invade and multiply in mammalian host cells. Here we report the isolation, biochemical characterization, developmental stage distribution and subcellular localization of chagasin, an endogenous cysteine protease inhibitor in T. cruzi. We used high temperature induced denaturation to isolate a heat-stable cruzipain-binding protein (apparent molecular mass, 12 kDa) from epimastigote lysates. This protein was subsequently characterized as a tight-binding and reversible inhibitor of papain-like cysteine proteases. Immunoblotting indicated that the expression of chagasin is developmentally regulated and inversely correlated with that of cruzipain. Gold-labeled antibodies localized chagasin to the flagellar pocket and cytoplasmic vesicles of trypomastigotes and to the cell surface of amastigotes. Binding assays performed by probing living parasites with fluorescein (FITC)-cruzipain or FITC-chagasin revealed the presence of both inhibitor and protease at the cell surface of amastigotes. The intersection of chagasin and cruzipain trafficking pathways may represent a checkpoint for downstream regulation of proteolysis in trypanosomatid protozoa.

Animals↗
PubMed2000

Histoplasmosis of the thyroid.

Fungal infection of the thyroid is rare. Most reported cases have involved Aspergillus, Coccidioides, and Candida species in the setting of disseminated disease. Infection of the thyroid with Histoplasma capsulatum is rarely reported as part of disseminated disease, even in geographic areas where histoplasmosis is endemic. We report a 52-year-old woman with a previous Hashimoto's disease and non-Hodgkin's lymphoma in which a diffuse enlarged thyroid gland with a large nodule was the only apparent locus of histoplasmosis. Fine-needle aspiration of the thyroid was an important diagnostic tool in establishing the diagnosis of histoplasmosis of the thyroid. The patient was initially treated with itraconazole (400 mg/day) for the fungal infection and six cycles of chemotherapy for the lymphoma. At a 6-month follow-up examination, the patient was doing well on suppressive therapy of itraconazole (200 mg/day), with no symptoms and with regression of the thyroid nodule and cervical adenopathy.

Antifungal Agents↗
PubMed1999

Validity of behavioral and physiologic parameters for acute pain assessment of term newborn infants.

CONTEXT: The subjectivity of pain causes enormous difficulties in evaluating neonatal pain with a single, practical and easy-to-apply tool. Pain evaluation in the neonatal period should be performed by valid, safe, useful and feasible methods. OBJECTIVE: To evaluate the validity of the Neonatal Facial Coding System (NFCS), Neonatal Infant Pain Scale (NIPS), heart rate (HR) and O2 saturation (O2 sat) for neonatal pain assessment. DESIGN: Prospective, double-blind randomized trial. SETTING: A secondary level maternity hospital. PARTICIPANTS: 70 healthy neonates requiring bilirubin dosage were randomly assigned to receive a venous puncture (P: n = 33, BW 3.2 kg, SD 0.6; GA 39 wk, SD 1; 59 h of life, SD 25) or an alcohol swab friction (F: n = 37; BW 3.1 kg, SD 0.5; GA 39 wk, SD 1; 52 h of life, SD 17). INTERVENTION: All measurements were taken prior to (PRE), during (TO), and 1 (T1), 3(T3), 5(T5) and 10(T10) minutes after the procedure. MEASUREMENTS: A neonatologist evaluated NFCS, NIPS, HR and O2 sat by pulse oxymetry. RESULTS: Median NFCS and NIPS results at T0, T1 and T3 were higher in P group, compared to F. More P neonates presented NFCS > 2 and/or NIPS > 3 at T0, T1 and T3. HR was lower in P group at T1. Average O2 sat was above 90% during the whole study period in both groups. CONCLUSION: NFCS and NIPS are suitable instruments for neonatal pain evaluation. Heart rate and O2 saturation can be used only as auxiliary methods.

Acute Disease↗
PubMed1998

Vulvar myiasis.

Myiasis is a parasitic infestation caused by larvae of several fly species. Diagnosis and treatment are simple. This infestation is, however, rarely seen in the vulvar area. We present a short review of the disease and the case of a 19-year-old pregnant girl with vulvar myiasis and concomitant syphilis, vaginal trichomoniasis and genital candidiasis. The patient was also positive for human immunodeficiency virus.

Adult↗
PubMed1998

Isolation and partial characterization of a lectin from Artocarpus incisa L. seeds.

A lectin was isolated from the saline extract of Artocarpus incisa seed by affinity chromatography on cross-linked Adenanthera pavonina galactomannan in 0.15 M NaCl. The lectin was also retained in a D-gal-agarose resin and had no requirements for divalent metal cations (Ca2+ and Mn2+) for activity. The lectin contains 2.1% of carbohydrate and is characterized by high contents of acidic and hydroxylated amino acids. The lectin presented two protein bands in SDS-PAGE, with M(r) 15.5 and 12 kDa, respectively, and contains no alpha-helix, 64% antiparallel beta-sheet and 21% parallel beta-sheet/beta-turn. When submitted to gel filtration in Superose 12 R (FPLC) and Superdex 75 HR 5/5 (HPLC) columns, the lectin showed an M(r) of 48-49 kDa, suggesting a tetrameric structure.

Amino Acids↗
PubMed1993

[Posttraumatic chylothorax. Experience in the postoperative period following cardiothoracic surgery].

PURPOSE: To report the accumulated experience in the treatment of patients with postoperative chylothorax (CHT) recovery utilizing pleural drainage associated to alipoidic diet and/or intravenous nutrition. METHODS: The aim of this work is to analyse the management of 11 patients (8 males; 11 months to 70 years old) with post-operative CHT. The previous pathologies were: congenital heart disease in 7; coronary insufficiency in 2; pulmonary tumor in 1 and mediastinal tumor in 1. The diagnosis was made up to 2nd postoperative week in 6, up to 4th week in 3 and later in 2 patients. The volume through the drain ranged from 200 to 3200ml/24h (median 636ml/24h). The laboratory diagnosis was made by lipidic presence in pleural effusion. In all patients the clinical management was made by hipo or alipoidic diet. RESULTS: In 7 the response was good with a decrease of drainage progressively. In 4, it was necessary the introduction of intravenous nutrition by the insufficient response and maintenance of drainage. The reoperation was not used and lymph fistula closed in a period until 10 days in 1 patient; until 20 days in 6 and after this in 4. CONCLUSION: In conclusion, the post-operative CHT may be treated by thoracic drainage and alipoidic diet and/or intravenous nutrition with fistula closure in all patients and without need of reoperation.

Adolescent↗
PubMed1991

[Myocardial revascularization after reperfusion in the acute phase of myocardial infarction].

PURPOSE: To evaluate the coronary artery bypass grafting (CABG) after successful coronary reperfusion (CR) by streptokinase and/or percutaneous transluminal coronary angioplasty in acute myocardial infarction (AMI). PATIENTS AND METHODS: During 65-months period, 245 patients underwent CR during AMI. In 47 (19.2%) CABG were performed in the acute period due to multi-vessel disease (31%), residual lesion (20%) and post-reperfusion angina (17%). There were two distinct periods: in the first, between Jun/81 and Jun/83, 34 patients underwent CABG, 47 hours average after reperfusion; in the second, between Jul/83 and Nov/86, 13 patients underwent CABG, 7 days average after reperfusion. RESULTS: There were 7 deaths (21%) in the first period and 1 (8%) in the second one. CONCLUSION: After a multifactorial analysis the authors concluded that better results with inferior mortality (p less than 0.05) were obtained when CABG was performed later (mean 7 days) than in the immediate post-reperfusion period (mean 47 hours).

Adult↗
PubMed1988

Local plasminogen activator and prostacyclin-like activity after partial venous occlusion--an experimental study in the dog.

After 90 min. of partial venous occlusion (40%) in dog's femoral vein plasminogen activator (t-PA) was decreased in the pre-occlusion segment and maintained in the post-occlusion segment. Prostacyclin-like activity (PLA) was maintained in the pre-, but increased in the post-occlusion segment. Treatment with heparin (loading dose-70/kg; IV perfusion-1 U/kg/min) did not affect pre-treatment pattern of t-PA or PLA in either segments. Treatment with aspirin (IV perfusion-2 mg/kg/min) promoted profound depression of PLA in both segments while t-PA remained unchanged. Treatment with lidocain (loading dose-1.5 mg/kg; IV perfusion 0.2 mg/kg/min) did not affect either PLA or t-PA in the pre-occlusion segment, but a decrease of these two activities was observed in the post-occlusion segment. We conclude that, since thrombin, prostaglandins and white blood cells were not responsible for all changes observed at t-PA and PLA vessel wall levels, it is justified, to evaluate the role of rheological factors as the probable determinant of these changes.

Animals↗