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Biomedical subjects

A C Guimarães

Publications and source records attributed to A C Guimarães.

At least 19 recordsLinked to original sources
PubMed2006

Cytotoxic and genotoxic monitoring of sickle cell anaemia patients treated with hydroxyurea.

Very satisfactory results have been obtained with the treatment of sickle cell anaemia with hydroxyurea (HU), an antineoplastic drug. This is because it significantly increases the levels of foetal haemoglobin. Nevertheless, inadequate dosages or prolonged treatment with this pharmaceutical can provoke cytotoxicity or genotoxicity, increasing the risk of neoplasia. We monitored patients under treatment with HU for possible mutagenic effects, through cytogenetic tests (mitotic index and chromosome aberrations) for one year. Checking at two-month intervals, the cytotoxic effect was not evident. There was no evidence of genotoxicity under the conditions of our experiment. However individuals treated with HU should be constantly monitored, as an absence of genotoxicity could be transitory; the mitotic index should also be observed, as an indicator of cytotoxicity.

Adolescent↗
PubMed2004

Conventional cytogenetic characterization of a new cell line, ACP01, established from a primary human gastric tumor.

Gastric cancer is the second most frequent type of neoplasia and also the second most important cause of death in the world. Virtually all the established cell lines of gastric neoplasia were developed in Asian countries, and western countries have contributed very little to this area. In the present study we describe the establishment of the cell line ACP01 and characterize it cytogenetically by means of in vitro immortalization. Cells were transformed from an intestinal-type gastric adenocarcinoma (T4N2M0) originating from a 48-year-old male patient. This is the first gastric adenocarcinoma cell line established in Brazil. The most powerful application of the cell line ACP01 is in the assessment of cytotoxicity. Solid tumor cell lines from different origins have been treated with several conventional and investigational anticancer drugs. The ACP01 cell line is triploid, grows as a single, non-organized layer, similar to fibroblasts, with focus formation, heterogeneous division, and a cell cycle of approximately 40 h. Chromosome 8 trisomy, present in 60% of the cells, was the most frequent cytogenetic alteration. These data lead us to propose a multifactorial triggering of gastric cancer which evolves over multiple stages involving progressive genetic changes and clonal expansion.

Adenocarcinoma↗
PubMed2002

Hypertension in Brazil.

PREVALENCE: Mean values for prevalence of hypertension in 18 selected populations, varied between 15.7% (BP > or = 95 mm Hg) and 27.7% (BP > or = 90 mm Hg). In three Mall surveys in Salvador (n = 5093 volunteers), prevalence mean value was 33.7% (JNC VI criteria), being influenced by age (5.5 to 17.8% and 41.0 to 54.9% for the 25-34 and 55-59 year old age groups, respectively) and socioeconomic class (24.7 and 39.6% for the highest and lowest social class, respectively, OR = 0.50 (0.26-0.95, P = 0.023). The national prevalence by the Ministry of Health is 20%. MORTALITY AND MORBIDITY: Mortality as a consequence of morbidity has increased, with stroke being a leading cause of death (11.3% of total deaths, 10.1% of all deaths in the 20-59 year-old age group, and 33.9% of cardiovascular deaths in Brazilian Capitals, 1994)Cardiovascular risk factors: At comparable age groups, prevalence of other major cardiovascular risk factors are: smoking approximately 27%, total cholesterol > or =200 mg/dl approximately 32.5%, glucose intolerance approximately 8.0%, diabetes approximately 7.5%, BMI 25-29 approximately 29.1%, BMI > or = 30 approximately 9.6%, and physical inactivity approximately 92%. AWARENESS, TREATMENT, AND CONTROL: Data are very scarce. In the total Mall population (n = 4613) in Salvador, a high blood pressure was present in 24.4% of those who either denied hypertension or ignored blood pressure. Of those who reported to be hypertensives, only 34.5% had their blood pressure <140/90 mm Hg. In a national inquiry including 2519 physicians, 88% would start treatment with drug monotherapy, diuretics (53%), and angiotensin-converting enzyme inhibitor (ACEI) (24%). If blood pressure control is not achieved, 55% will combine with another drug (diuretic + ACEI (46%) or + beta-blocker (24%)), and 33% will increase the dosage. Nonpharmacological treatment would be prescribed for every patient by 17% of the physicians, while 62% would prescribe it for 25% of their patients. Adhesion is better for pharmacological (60%) than for nonpharmacological treatment (8%). FINAL REMARKS: Three Consensus Documents (the most recent in 1998), the creation of the Department of Hypertension Leagues, the Fighting Hypertension National Day, the Confederation of Hypertensive Patients Associations, and the very recent launch of the National Plan for Reorganization of Hypertension and Diabetes Care are some measures being taken in a joint effort of the Ministry of Health and the Brazilian Societies of Cardiology, Hypertension and Nephrology, to strengthen and improve the fight against hypertension.

Adult↗
PubMed2001

Ultrastructural aspects of oogenesis and oocyte primary growth in Serrasalmus spilopleura (Teleostei, Characiformes, Characidae).

The ultrastructural characteristics of the organelles present in Serrasalmus spilopleura oogonia and oocytes undergoing primary growth were described in detail, considering its role in the nuclear and cytoplasmic metabolic processes that occur in these cell types. Even though these cells do not significantly differ from those similar to them that are found in other teleost groups, the analysis of their ultrastructure makes available new data on the reproductive biology of Characiformes.

Animals↗
PubMed1999

Evaluation of anti-inflammatory-related activity of essential oils from the leaves and resin of species of Protium.

The resins and leaves of species of Protium are commonly used by folk medicine. In the present study, we analyse the pharmacological effects of essential oils obtained by steam distillation (leaves and resin) from Protium species. Analysis by gas chromatography (GC) coupled to mass spectrometry and retention indices calculations demonstrate that the resin oil is constituted mainly of monoterpenes and phenylpropanoids: alpha-terpinolene (22%), p-cymene (11%), p-cimen-8-ol (11%), limonene (5%) and dillapiol (16%), whereas sesquiterpenes predominate as the volatile constituents of the leaves. The resin of Protium heptaphyllum (PHP) and leaves of P. strumosum (PS), P. grandifolium (PG), P. lewellyni (PL) and P. hebetatum (PHT) were screened for anti-inflammatory activity by the use of mouse pleurisy model induced by zymosan (500 microg/cavity) and lipopolysaccharide (LPS) (250 ng/cavity), for antinociceptive effect (by means of preventing mice abdominal writhings), as well as NO production from stimulated macrophages and proliferation of neoplasic cell lines: Neuro-2a (mouse neuroblastoma), SP2/0 (mouse plasmocytoma) and J774 (mouse monocytic cell line). The oils from PHP, PS and PL were able to inhibit protein extravasation but no sample inhibited total or differential leucocyte counts after administrating p.o. (100 mg/kg) 1 h before stimulation with zymosan. The oils from PG, PL and PHT inhibited neutrophil accumulation whereas PHP and specially PL inhibited LPS-induced eosinophil accumulation in mouse pleural cavity. PHT was also able to inhibit mononuclear cells accumulation. Antinociceptive effect was not observed, when animals received oral administration of the essential oils (100 mg/kg). In vitro treatment with essential oils (100 microg/well) changed the NO production from stimulated mouse macrophages. PHP inhibited in 74% and PS in 46% the LPS-induced NO production. In contrast, treatment with PL was able to increase in 49% the NO production. Cell lines proliferation was affected by the oils assayed in the range of 60-100% for Neuro-2a, 65-95% for SP2/0 and 70-90% for J774. Taken together these results showed that essential oils could be useful as efficient pharmacological tools.

Animals↗
PubMed1998

EMG-force relation in dynamically contracting cat plantaris muscle.

The purpose of this study was to revisit the electromyographical (EMG)-force relationship of dynamically contracting muscles using direct measurements of EMG and force in cat hindlimb muscles during locomotion. EMG signals were recorded from the plantaris muscle using bipolar indwelling wire electrodes, and the corresponding forces were measured using a tendon force transducer. Force-time histories of cat plantaris muscle were predicted by estimating selected force parameters from EMG and timing parameters, and then constructing two smoothly fitting quintic spline functions from the estimated force parameters. The force predictions did not contain information on force-length or force-velocity properties of the cat plantaris and did not use instantaneous contractile conditions as input. It was found that two smoothly fitting quintic spline functions provided the required properties to approximate plantaris force-time histories accurately, and approximations of the force-time histories using EMG and timing parameters as input for the quintic splines were good. The root mean square errors (RMS) of the predicted compared to the actual plantaris forces were smaller than corresponding results reported in the literature, even though the prediction model did not require the force-length-velocity properties or the instantaneous contractile conditions of the target muscles as input. From the results obtained in this study, it appears that force-time histories of the cat plantaris muscle during locomotion can be predicted adequately from information obtained using EMG and video records, without information on either the force-length and force-velocity properties, or the instantaneous contractile conditions of the muscle.

Algorithms↗
PubMed1998

Detection in human sera of IgG, IgM and IgA to excreted/secreted antigens from Toxoplasma gondii by use of dot-ELISA and immunoblot assay.

The excreted/secreted antigens (ESA) of Toxoplasma gondii are thought to play an important role in the pathogenesis and immune escape of the parasite and the host's immunity to infection with it. In the present study, ESA from peritoneal exudates of infected mice were precipitated with ammonium sulphate (a 40% saturated solution giving the best yield of antigenic components). They were then analysed by immunoblot assay and dot-ELISA using serum samples from 25 patients with toxoplasmosis (19 in the acute phase and six chronic). Three groups of antigens, with molecular masses of 35, 30-32 and 26 kDa, reacted strongly with IgG antibodies, and antigens from two of these groups (30-32 and 26 kDa) also reacted with IgM and IgA.

Acute Disease↗
PubMed1998

Western blot detection of infectious bursal disease virus infection.

In order to evaluate the use of a Western blot methodology for the diagnosis of infectious bursal disease virus (IBDV) infection, chickens were experimentally infected with IBDV strains and tested for the presence of viral antigens and antibodies by a blocking Western blot test (bWB). The viral proteins obtained from the bursa of Fabricius (BF) were transferred to a nitrocellulose membrane after sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and the chicken sera obtained by heart puncture were used for the detection of these proteins. In order to eliminate nonspecific reactions, we used a rabbit anti-chicken serum (blocking tool). By the use of the bWB test, two distinct viral proteins of 43-kDa (VP2) and 32-kDa (VP3) were detected. We suggest the use of this methodology for the detection of IBDV infection in animals suspected of having IBDV reinfection and a chronic subclinical form of the disease. With the use of the rabbit anti-chicken sera for blocking, this method is practical, sensitive and less time consuming.

Animals↗
PubMed1998

Santo Inácio revisited: protozoan diseases in an isolated village in northeastern Brazil after twenty years.

The northeastern highlands of Brazil are endemic for several tropical diseases, especially American trypanosomiasis (Chagas' disease) and schistosomiasis. Twenty years ago, we measured the seroprevalence of protozoan diseases in Santo Inácio, a village of approximately 1,000 inhabitants located 1,000 m above sea level. We detected small numbers of sera with antibodies against Trypanosoma cruzi and Toxoplasma gondii, and the area had a low prevalence both of American trypanosomiasis (3.54%) and toxoplasmosis (27.43%) compared with nearby Brazilian areas. This was attributed to a specific triatomine vector and local housing conditions. Twenty years later, we again determined the prevalences of both diseases and compared these results with those from Iraquara, a larger town with the same ethnic and social background but with a higher prevalence of rural activities. The incidence of Chagas' disease in San Inácio showed the same low level, i.e., 3.78% (5 of 132) with only adult males affected in contrast with Iraquara, which had an incidence of 34.5%, but a low prevalence of only one of 22 among children up to 14 years of age. Santo Inácio maintained a low (25.8%) seroprevalence for toxoplasmosis. Housewives presented a higher incidence of toxoplasmosis during both periods, probably due to related risk factors. Cats were found less frequently in Santo Inácio than in Iraquara, which showed an incidence of 65.5% seropositivity for Toxoplasma gondii. These results suggest that the environmental conditions of Santo Inácio were preserved after 20 years, with a low incidence of these selected protozoan diseases.

Adolescent↗
PubMed1997

Rotavirus and reovirus interaction with mouse peritoneal resident phagocytic cells.

Rotaviruses and reoviruses are involved in human and animal diseases. It is known that both viruses penetrate the gastrointestinal tract but their interaction with phagocytic cells is unknown. To study this interaction, peritoneal resident phagocytic cells were used and rotavirus and reovirus replication in peritoneal phagocytic cells was observed. However, rotavirus replication in these cells led to the production of defective particles since MA-104 cells inoculated with rotavirus phagocytic cell lysate did not show any evidence of virus replication. On the basis of these results, we suggest that, although reovirus dissemination may be helped by these phagocytic cells, these cells may control rotavirus infection and probably contribute to the prevention of its dissemination.

Animals↗
PubMed1994

[The lipid profile and coronary artery disease].

PURPOSE: To correlate lipid profile with coronary artery disease (CAD). METHODS: One hundred patients with symptoms of CAD were studied by coronariography: 62 males (55.6 +/- 9.26 years) and 38 females (56.3 +/- 9.72 years). Blood glucose, total cholesterol (TC), triglycerides (TG), and HDL-C (n = 96) levels were determined; LDL-C was calculated by the Friedewald formula. Coronary artery stenotic and normal proximal lumen were measured with a pachymeter, and the percent degree of obstruction calculated. The proximal, medial and distal segments of left anterior descending (LAD), circumflex (CX), right coronary artery (RCA) and the coronary trunk, 1st LAD diagonal branch and 1st RCA marginal branch were analysed. RESULTS: Coronariography: CAD was documented in 74 patients, (56-75.6% men), with > or = 50% stenosis in 67 (90.5%), 54 (79.1%) men. The lesions were univessel in 24 (33.4%), bivessel in 29 (39.7%), and trivessel in 20 (27.4%). Seventy patients had TC > or = 200 mg/dl, 29 (41.4%) > or = 240 mg/dl); 69 (71.9%) LDL-C > or = 130 mg/dl, 37 (38.5%) > or = 160 mg/dl; 35 (36.5%) HDL-C < 35 mg/dl and 10 TG > or = 200 mg/dl. Lipid profile vs CAD -1) CAD patients had lower HDL-C values (38.8 +/- 10 mg/dl vs 48.2 +/- 13.6 mg/dl, p = 0.01) and higher Castelli risk indexes (CRI) (TC/HDL-C = 5.9 +/- 1.7 vs 5.1 +/- 1.4 and LDL-C/HDL-C = 4.1 +/- 1.5 vs 3.4 +/- 1.2, p = 0.04); 2) > or = 50% stenosis and multivessel disease showed higher CRI (p = 0.01 and p = 0.04 for TC/HDL-C, and p = 0.01 and p = 0.02 for LDL-C/HDL-C, respectively). Twenty one (70%) of the 30 patients with TC < 200 mg/dl had CAD (28% of the patients with CAD), in whom there was a high frequency of patients with a low HDL-C level (11/21, 52.4% vs 3/9, 33%, p = 0.06). CONCLUSION: Lower HDL-C and higher CRI values were associated with more severe and intensive CAD; TC < 200 mg/dl is compatible with CAD, specially if there is a low HDL-C level. These findings strengthen the need of HDL-C measurement for CAD risk assessment.

Aged↗
PubMed1991

[Evaluation of endomyocardial fibrosis by two-dimensional echocardiogram. Analysis of the severity and correlation with angiocardiography].

PURPOSE: To evaluate the capacity of two-dimensional echocardiogram (2D-Echo) to establish the severity of endomyocardial fibrosis (EMF) in comparison with angiography (Angio). METHODS: Twelve patients with EMF were prospectively studied by both: 2D-Echo and Angio. The mean age was 24.6 +/- 6.6 years (14 to 35), with 8 women and 4 men. To compare the severity by the 2 methods the obliterative process was graded according to its extension relative to the long axis of the respective, in diastole, as follows: 1 + only apical: 2 + less than 50% and 3 + greater than or equal to 50% from the apex to the atrioventricular valve level. RESULTS: All patients (100%) had biventricular disease by Angio, with right ventricle (RV) predominance in 5 (42%), left ventricle (LV) predominance in 1 (8%) and balanced in 6 (50%). By 2D-Echo the se numbers were: 11 (92%), 5 (42%), 1 (8%) and 5 (42%), respectively. The degree of concordance between 2D-Echo and Angio was 100% for the RV and 75% for the LV (p less than 0.005). In only 1 patient the LV apical involvement (+) was not identified by 2D-Echo. Mitral insufficiency (MI) was detected in 7 (58%) and tricuspid (TI) in 11 (92%) patients by Angio. These patients, expect one, had the corresponding atrial area greater than 18 cm2 by 2D-Echo. It was observed a statistically significant correlation between the atrial area and the degree of AV valve insufficiency (MI p less than 0.005; TI p less than 0.05). Paradoxical movement of the interventricular septum (IVS) was noted in 6 (50%) patients, associated with predominant RV disease, severe TI and mild or absent MI. CONCLUSION: The 2D-Echo, a valuable non-invasive method to diagnose and to grade severity of the fibrotic involvement of the ventricles by EMF, has a good correlation with Angio.

Adolescent↗
PubMed1990

A nine year prospective study of Chagas' disease in a defined rural population in northeast Brazil.

The association between infection with Trypanosoma cruzi and the development of electrocardiographic alterations and mortality was studied longitudinally for 9 years in a population residing in an endemic area in Castro Alves, Bahia, Brazil. Annual censuses were begun in 1973. At 3 year intervals from 1974 to 1983, the population was examined serologically and subjected to electrocardiography using standardized techniques. Of 1,751 individuals registered during the 10 censuses, 1,541 (88%) were examined serologically at least once. Of 747 individuals in constant residence and originally seronegative, 24 were seropositive upon subsequent evaluation, giving a seroconversion rate of 4.92/1,000 person-years (PY). The overall rate of development of an abnormal ECG was 25.7/1,000 PY for seropositive individuals and 12.5/1,000 PY for seronegative individuals, a relative risk of 2. The 10-14-year-old seropositive group had the highest risk of developing ECG abnormalities (24.1/1,000 PY, relative risk = 3.5). The age-adjusted mortality rate of seropositive individuals was slightly higher than for seronegative individuals (8.9 vs. 7.8/1,000 PY). In sero-positive individuals, mortality was strongly associated with the presence of ventricular conduction defects and arrhythmias. Ventricular conduction defects appeared most frequently in younger individuals. Older individuals presented the highest risk of development of frequent and multifocal extrasystoles.

Adolescent↗
PubMed1987

Cardiac morbidity and mortality due to Chagas' disease: prospective electrocardiographic study of a Brazilian community.

The evolution of Chagas' cardiomyopathy is poorly understood. We therefore examined the development of cardiac lesions in a rural Brazilian community for a period of 7 years. Initially, 42% of 1017 residents were seropositive for infection with Trypanosoma cruzi. Age-specific infection rates indicated that most had become infected before the age of 20 years. On follow-up, it appeared that those persons who developed cardiac lesions did so soon after infection, since the incidence of right bundle branch block and other ventricular conduction defects (VCDs) was also highest before age 20 years. The progressive nature of these lesions was demonstrated by frequent development of additional electrocardiographic abnormalities and high mortality among infected adults with VCDs. In contrast, mortality was low and approximately the same for seropositive and seronegative adults under 60 years who had normal electrocardiograms. Electrocardiography during the early asymptomatic stage of infection was able to distinguish persons with potentially lethal cardiac lesions from those with a benign prognosis.

Age Factors↗