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Biomedical subjects

A Oliveira

Publications and source records attributed to A Oliveira.

At least 19 recordsLinked to original sources
PubMed2006

Impact of an herbicide combination of bromoxynil and prosulfuron on soil microorganisms.

Soil microcosm experiments were used to investigate the effects on growth and activity of soil microorganisms of an herbicide combination (60% bromoxynil + 3% prosulfuron) frequently used to provide a broad spectrum control of weed species. Culturable aerobic bacteria, fungi, and actinomycetes, the fundamental groups of heterotrophic microorganisms, and nitrifiers, considered a very sensitive group to these compounds, were evaluated. Since herbicides have been found to inhibit decomposition of cellulose in soil, the effects on cellulolytic bacteria and fungi were determined. Dehydrogenase activity as a measure of microbial activity was another parameter considered. The results emphasized a tendency of reversible stimulatory/inhibitory effects of the tested compounds on soil microorganisms, with fungi as an exception. A long-lasting negative action on the activity of the dehydrogenase (DHA), commonly used as an index of the overall microbial activity in soil, was found. The magnitude of these effects were dependent on the assayed concentrations of the herbicides mixture. We concluded that the presence of bromoxynil + prosulfuron could induce significant changes in the microbial populations of the soil, concerning the activity and balance of microbial community. Possible environmental risks must be considered. Dehydrogenase activity was shown to be an important indicator of side-effects attributed to these herbicides.

Actinobacteria↗
PubMed2005

Relationship between gene polymorphisms and prevalence of myocardial infarction among diabetic and non-diabetic subjects.

This study was aimed to examine cholesteryl ester transfer protein (CETP), apolipoprotein AI and CIII gene polymorphisms, and to verify whether these genetic determinants are associated with the prevalence of myocardial infarction (MI) or type 2 diabetes. The TaqIB restriction fragment length polymorphism (RFLP) in intron I of the CETP gene, the MspI in the third intron of the APOAI gene, and also SstI in the 3' untranslated region of the APOCIII gene were determined using standard methods. The prevalence of these polymorphisms was compared between diabetic (n = 119), and non-diabetic (n = 100) middle-aged individuals of both sexes. We found a higher prevalence of the B2B2 genotype of the CETP gene among diabetics than that observed in non-diabetics (P < 0.05), and a lower prevalence of this genotype among patients with previous MI (P < 0.02). The MspI polymorphisms of the APOAI gene showed that M1++ genotype was found mainly in diabetic patients (P < 0.04). Conversely, the SstI polymorphism of APOCIII gene was not significantly associated with either MI or diabetes. Therefore, among these genetic polymorphisms, TaqIB of CETP and MspI of apolipoprotein AI appeared to help significantly to identify diabetic individuals. In particular, the former may have an additional role in the primary prevention of coronary disease.

Apolipoprotein A-I↗
PubMed2005

High prevalence of vasomotor reflex impairment in newly diagnosed leprosy patients.

BACKGROUND: Initial nerve damage in leprosy occurs in small myelinated and unmyelinated nerve fibers. Early detection of leprosy in the peripheral nervous system is challenging as extensive nerve damage may take place before clinical signs of leprosy become apparent. PATIENTS AND METHODS: In order to determine the prevalence of, and factors associated with, peripheral autonomic nerve dysfunction in newly diagnosed leprosy patients, 76 Brazilian patients were evaluated prior to treatment. Skin vasomotor reflex was tested by means of laser Doppler velocimetry. Blood perfusion and reflex vasoconstriction following an inspiratory gasp were registered on the second and fifth fingers. RESULTS: Vasomotor reflex was impaired in at least one finger in 33/76 (43%) patients. The fifth fingers were more frequently impaired and suffered more frequent bilateral alterations than the second fingers. Multivariate regression analysis showed that leprosy reaction (adjusted odds ratio = 8.11, 95% confidence interval: 1.4-48.2) was associated with overall impaired vasomotor reflex (average of the four fingers). In addition, palmar erythrocyanosis and an abnormal upper limb sensory score were associated with vasomotor reflex impairment in the second fingers, whereas anti-phenolic glycolipid-I antibodies, ulnar somatic neuropathy and a low finger skin temperature were associated with impairment in the fifth fingers. CONCLUSIONS: A high prevalence of peripheral autonomic dysfunction as measured by laser Doppler velocimetry was observed in newly diagnosed leprosy patients, which is clinically evident late in the disease. Autonomic nerve lesion was more frequent than somatic lesions and was strongly related to the immune-inflammatory reaction against M. leprae.

Adolescent↗
PubMed2004

Maternal milk as methylmercury source for suckling mice: neurotoxic effects involved with the cerebellar glutamatergic system.

Methylmercury (MeHg) is a highly neurotoxic compound and several studies have reported intoxication signs in children whose mothers were exposed to this environmental toxicant. Although it is well established that the in utero exposure to MeHg causes neurological deficits in animals and humans, there is no evidence of the exclusive contribution of lactational exposure to MeHg as a possible cause of neurotoxicity in the offspring. In this study, we investigated the exclusive contribution of MeHg exposure through maternal milk on biochemical parameters related to the glutamatergic homeostasis (glutamate uptake by slices) and to the oxidative stress (total and nonprotein sulfhydryl groups, nonprotein hydroperoxides, glutathione peroxidase and catalase activities) in the cerebellum of suckling mice (Swiss albino). The same parameters were also evaluated in the cerebellum of mothers. Our results showed, for the first time, that lactational exposure to MeHg caused a high percent of inhibition (50%) on glutamate uptake by cerebellar slices in pups. Contrarily, this effect was not observed in mothers, which were submitted to a direct oral exposure to MeHg (15 mg/l in drinking water). In addition, behavioral/functional changes were observed in the weaning mice exposed to MeHg. It was observed an increase in the levels of nonprotein hydroperoxides in cerebellum, and this increase was negatively correlated to the glutamate uptake by cerebellar slices. This study indicates that (1) the exposure of lactating mice to MeHg causes inhibition of the glutamate uptake by cerebellar slices in the offspring; (2) this inhibitory effect seems to be related to increased levels of hydroperoxide.

Animals↗
PubMed2004

STING Contacts: a web-based application for identification and analysis of amino acid contacts within protein structure and across protein interfaces.

UNLABELLED: Amino acid contacts in terms of atomic interactions are essential factors to be considered in the analysis of the structure of a protein and its complexes. Consequently, molecular biologists do require specific tools for the identification and visualization of all such contacts. Graphical contacts (GC) and interface forming residue graphical contacts (IFRgc) presented here, calculate atomic contacts among amino acids based on a table of predefined pairs of the atom types and their distances, and then display them using number of different forms. The inventory of currently listed contact types by GC and IFRgc include hydrogen bonds (in nine different flavors), hydrophobic interactions, charge-charge interactions, aromatic stacking and disulfide bonds. Such extensive catalog of the interactions, representing the forces that govern protein folding, stability and binding, is the key feature of these two applications. GC and IFRgc are part of STING Millennium Suite. AVAILABILITY: http://sms.cbi.cnptia.embrapa.br/SMS, http://trantor.bioc.columbia.edu/SMS, http://mirrors.rcsb.org//SMS, http://www.es.embnet.org/SMS and http://www.ar.embnet.org/SMS (Options: Graphical Contacts and IFR Graphical Contacts).

Algorithms↗
PubMed2003

Detection of fusion gene transcripts in fresh-frozen and formalin-fixed paraffin-embedded tissue sections of soft-tissue sarcomas after laser capture microdissection and rt-PCR.

The diagnosis of small round cell sarcomas is often very difficult, especially when only small biopsy specimens are available for examination. Recent studies have shown that some sarcomas have specific recurrent chromosomal translocations producing chimeric gene fusions, which can be detected by reverse transcription-polymerase chain reaction (RT-PCR), fluorescent in situ hybridization (FISH), or cytogenetic analysis. In this study, 12 cases of well-defined sarcomas including Ewings sarcoma/primitive neuroectodermal tumors (ES/PNET), synovial sarcoma (SS), alveolar rhabdomyosarcoma (ARMS), and desmoplastic small round cell tumors (DSRCT) were used to collect specific numbers of cells by laser capture microdissection (LCM), subsequently used for RT-PCR to detect specific chimeric gene transcripts. Tumor cells from fresh-frozen (FS) tissue sections and paraffin-embedded (PS) tissue sections from the same cases were compared directly to evaluate the sensitivity of FS and PS sections as the starting material for analysis. Samples were used for RNA extraction, RT-PCR analysis, and Southern hybridization with fluorescein-labeled internal probes followed by enhance chemiluminescence (ECL) detection. The fusion gene transcripts could be detected using 50 cells from FS materials in all cases and from 1 cell in 9 of 12 cases. For PS, a positive signal could be detected using 200 to 1000 cells in all cases, while weaker signals were detected using 50 cells in most cases. These results indicate that the fusion gene products from small round cell sarcomas can be detected by RT-PCR with 10 to 200 cells from FS and PS tissues. The sensitivity of RT-PCR with FS was 10- to 50-fold greater than with PS. These results also suggest that RT-PCR analysis for sarcoma fusion gene products can be successfully performed when only a few cells are available for analysis, although this is not recommended for routine clinical use.

Blotting, Southern↗
PubMed2002

Heat storage rate and acute fatigue in rats.

Thermal environmental stress can anticipate acute fatigue during exercise at a fixed intensity (%VO2max). Controversy exists about whether this anticipation is caused by the absolute internal temperature (Tint, degrees C), by the heat storage rate (HSR, cal/min) or by both mechanisms. The aim of the present study was to study acute fatigue (total exercise time, TET) during thermal stress by determining Tint and HSR from abdominal temperature. Thermal environmental stress was controlled in an environmental chamber and determined as wet bulb globe temperature ( degrees C), with three environmental temperatures being studied: cold (18 degrees C), thermoneutral (23.1 degrees C) or hot (29.4 degrees C). Six untrained male Wistar rats weighing 260-360 g were used. The animals were submitted to exercise at the same time of day in the three environments and at two treadmill velocities (21 and 24 m/min) until exhaustion. After implantation of a temperature sensor and treadmill adaptation, the animals were submitted to a Latin square experimental design using a 2 x 3 factorial scheme (velocity and environment), with the level of significance set at P<0.05. The results showed that the higher the velocity and the ambient temperature, the lower was the TET, with these two factors being independent. This result indicated that fatigue was independently affected by both the increase in exercise intensity and the thermal environmental stress. Fatigue developed at different Tint and HSR showed the best inverse relationship with TET. We conclude that HSR was the main anticipating factor of fatigue.

Animals↗
PubMed2001

Substrate specificity of human cathepsin D using internally quenched fluorescent peptides derived from reactive site loop of kallistatin.

Kallistatin, a serpin that specifically inhibits human tissue kallikrein, was demonstrated to be cleaved at the Phe-Phe bond in its reactive site loop (RSL) by cathepsin D. Internally quenched fluorescent peptides containing the amino acid sequence of kallistatin RSL were highly susceptible to hydrolysis by cathepsin D. Surprisingly, these peptides were efficiently hydrolyzed at Phe-Phe bond, despite having Lys and Ser at P2 and P2' positions, respectively, which was reported to be very unfavorable for substrates for cathepsin D. Due to the importance of cathepsin D in several physiological and pathological processes, we took the peptide containing kallistatin RSL sequence, Abz-Ala-Ile-Lys-Phe-Phe-Ser-Arg-Gln-EDDnp, as a reference substrate for a systematic specificity study of S3 to S3' protease subsites (EDDnp=N-[2,4-dinitrophenyl]-ethylenediamine and Abz=ortho-amino benzoic acid). We present in this paper some internally quenched fluorescent peptides that were efficient substrates for cathepsin D. They essentially differ from other previously described substrates by their higher kcat/Km values due, mainly, to low Km values, such as the substrate Abz-Ala-Ile-Ala-Phe-Phe-Ser-Arg-Gln-EDDnp (Km=0.27 microM, kcat=16.25 s(-1), kcat/Km=60185 microM(-1) x s(-1)).

Amino Acid Sequence↗
PubMed2001

Transradial approach for coronary interventions.

OBJECTIVE: To assess the feasibility and safety of coronary interventions performed through the radial artery. METHODS: We studied 103 patients with ages from 38 to 86 years (57+/-8.7), 90 (87%) males, and: radial pulse with a good amplitude, presence of ulnar pulse, a good collateral flow through the palmar arch assessed with the Allen's test. RESULTS: The vascular approach was obtained in 97 (94%) patients, 88 (91%) treated electively and 9 (9%) during acute myocardial infarction, for primary angioplasty; 56 (64%) unstable angina; 22 (25%) stable angina; 10 (11%) were asymptomatic, 6 referred for recanalization of chronic occlusion and 4 silent ischemia in the first week after acute myocardial infarction. We approached 107 arteries: anterior descending artery, 49 (46%); right coronary artery, 27 (25%); circumflex artery, 25 (23%); diagonal artery, 6 (6%); and 2 saphenous vein bypass grafts. We treated 129 lesions: 80 (62%) B2 type; 23 (18%) B1 type; 17 (13%) C type; and 9 (7%). A type. There were 70 stents, and 59 balloon angioplasties performed. Thirty-two (33%) patients used GP IIb/IIIa inhibitors. The mean duration of the elective procedure was 42.3+/-12.8 min. Success, correct stent deployment and residual lesion <20%, was reached in 100% of the lesions treated with stent implantation; arterial dilation with residual lesion <50% was obtained in 96% of the lesions treated with transluminal coronary angioplasty (TCA). Complications, were: 1 (1.0%) non-Q-wave acute myocardial infarction; 2 (2%) hematomas in the forearm; and 2 losses of radial pulse. CONCLUSION: Radial artery approach is practical and safe for percutaneous coronary interventions there was a low incidence of complications.

Adult↗
PubMed2001

Transesophageal echocardiography in the assessment of patients presenting with ischemic cerebral events without previous evidence of a cardiac source of emboli.

UNLABELLED: Transesophageal echocardiography (TEE) is accepted as a valuable tool in the evaluation of ischemic stroke patients, particularly in the young and in cases of unknown cause. However, the real clinical impact of additional TEE data remains to be defined. PURPOSE: The aim of this study was to present our experience with TEE in ischemic stroke patients without previous evidence of a cardiac source of emboli. METHODS: From March 1991 to June 2000 we studied 172 patients (80 males, 92 females, mean age 43 +/- 12 years presenting with a transient ischemic attack or a recent cerebral infarction who had no previous evidence by clinical assessment, electrocardiogram and transthoracic echocardiography of a cardiac of emboli source. The population was divided into two groups: Group A--age < or = 45 years, n = 101 (43 males, 58 females, mean age 34 +/- 7 years) and Group B--age > 45 years, n = 71 (36 males, 35 females, mean age 54 +/- 7 years). Information was gathered from clinical records. In every case TEE included Doppler color flow imaging and multiple contrast injections (agitated saline) with and without Valsalva maneuver. RESULTS: A potential cardiac of emboli source was found in 29% of the patients, with a higher prevalence in the older group (group A--25%, Group B--35%, ns). Atrial septal abnormalities accounted for most of the detected findings (23 patent foramen ovale, 17 atrial septal aneurysms and two atrial septal defects, representing altogether 71% of the findings). The other detected anomalies were distributed as follows: aortic plaques--six, mitral valve prolapse--five vegetations--four, thrombus in left atrial appendage--two. Only six patients (3.5%) had abnormalities which in themselves determined a specific approach, which were found mostly in the older group (Group A--two vegetations; Group B--two vegetations, two thrombi). CONCLUSIONS: TEE identified additional findings with possible embolic potential in a considerable number of cases, the majority of which were of a debatable cause-effect relation. A higher diagnostic yield and clinical relevance was found in older patients, which argues against age being used as a selective criterion for it. Our experience suggests that routine TEE in this setting is of questionable value and has little impact on clinical management, for which reason TEE referral should be decided on an individual patient basis.

Brain Ischemia↗
PubMed2000

The role of associated injuries on outcome of blunt trauma patients sustaining pelvic fractures.

In order to identify the prognostic factors and to evaluate the impact of associated injuries in the outcome of patients with pelvic fractures, a retrospective review of the medical records of patients admitted with a pelvic fracture during a 42-month period was carried out. Demographic data, the mechanism of injury, the physiologic status on admission, associated injuries, pelvic fracture classification, complications and mortality were analysed. One hundred and three patients were included in the study. Fifty-nine were male, and the mean age was 34. The mean Revised Trauma Score (RTS) and Injury Severity Score (ISS) were 7.1 and 20, respectively. Pedestrian vs vehicle (59%), was the most frequent mechanism of injury. Twenty patients died (19%) most frequently due to "shock". Complications developed in 37 patients (36%), pneumonia being the most frequent. Age greater than 40 years (p=0.02), "shock" upon admission (p=0.002), a Glasgow Coma Scale (GCS)<9, Head AIS>2 (p<0. 001), Chest AIS>2 (p=0.007), and abdominal AIS>2 (p=0.03) all correlated with increased mortality. No correlation between pelvic fracture classification or fracture stability with mortality was observed. The outcome of patients with pelvic fractures due to blunt trauma correlates with the severity of associated injuries and physiological derangement on admission rather than with characteristics of or the type of fracture.

Accidents, Traffic↗
PubMed2000

Humoral intestinal immunity in systemic lupus erythematosus.

Forty-five patients with systemic lupus erythematosus (SLE) underwent a cross-sectional study to evaluate intestinal secretory immunity. Peroral jejunal biopsy with histologic and immunohistochemical assessment of the mucosa were carried out in the patients and in 12 healthy volunteers. It was observed that an altered pattern of immunoglobulin-bearing plasma cells distributed in the lamina propria and complementary components were invariably present, mainly in the patients with active disease. The basement membrane of the intestinal crypt epithelium exhibited immunoglobulin and complementary deposits, similar to the lupus band test. None of the immunologic findings correlated with the medical treatment and with the peripheral blood analysis. The local changes in humoral immunity in patients with SLE did not correlate with gastrointestinal symptoms and may reflect the systemic effects of the disease.

Adolescent↗
PubMed1999

Acid-base properties and solubility of pindolol, diazepam and chlordiazepoxide in SDS micelles.

The effect of sodium dodecyl sulphate (SDS) on the acid-base properties and on the solubility of a beta-blocker (pindolol) and of two benzodiazepines (diazepam and chlordiazepoxide) has been assessed. The study was performed by potentiometric and spectrophotometric determinations of the acidity constants and by spectrophotometric evaluation of the solubilities of the pharmaceutical drugs in aqueous solution and in solutions to which was added SDS with concentrations below and above the critical micelle concentration (cmc), at 25 degrees C and at an ionic strength 0.1 M (NaCl). The effect of the organized assemblies on the pKa values was quantified by the application of two theoretical models that differ in the inclusion of ionic exchange between positively charged species in solution. These models have allowed the determination of the binding constants for drug/micelle and yielded values in good agreement with those obtained by the solubility method, and in addition provide a more detailed picture of the effect of drug charge on its partition. The results can be taken to evidence different interaction modes of the drugs with the SDS micelles.

Adrenergic beta-Antagonists↗
PubMed1999

[Polymorphism of the IL1RN gene in Spanish patients with ulcerative colitis].

BACKGROUND: The etiology of the inflammatory bowel disease is unknown. Previous studies have shown an association between the allele 2 of IL1RN, the gene that encodes for the interleukin 1 receptor antagonist (IL-1ra), and the inflammatory bowel disease. PATIENTS AND METHODS: We have analyzed the incidence of the IL1RN alleles in 41 patients with ulcerative colitis and in 40 healthy subjects. RESULTS: Our results show the same allelic distribution between the subjects with ulcerative colitis and the healthy population. CONCLUSIONS: These results suggest that the allelic variants of the VNTR of the IL-1ra gene are not associated to a higher susceptibility to ulcerative colitis in Spanish population.

Adolescent↗
PubMed1999

[Radiation therapy and cardiac pacemakers].

The number of patients with cardiac pacemakers submitted annually to radiation therapy is increasing. Radiation therapy causes interference in the normal functioning processes, directly by chemical changes in the structure of the device and also by electromagnetic disturbances generated in the process of treatment. The changes in the technology used in the manufacture of cardiac pacemakers after the 70's, with the introduction of complementary metal-oxide semi-conductors (CMOS) in the circuits, drastically increased the chance of dangerous interference in the normal function of cardiac pacemakers occurring when in contact with an ionizing radiation source. The authors briefly describe the mechanisms underlying the radio-induced damage usually observed. A review of the literature on this issue is made and solutions are pointed out to perform safe radiation therapy and minimize the risk of device malfunction.

Equipment Failure↗
PubMed1998

[Microangiopathic hemolytic anemia. A form of presentation of stomach neoplasm].

The authors report the case of a 53-year-old female with symptomatic anemia and hemorrhagic diathesis. The patient presented thrombocytopenia, microangiopathic hemolytic anemia and leukoerythroblastic reaction in peripheral blood film. The diagnosis of metastatic gastric carcinoma was made by subsequent studies. A review is made of the literature concerning microangiopathic hemolytic anemia, namely its etiology, mechanisms of pathogenesis and association with metastatic carcinoma.

Adenocarcinoma↗