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A M de Almeida

Publications and source records attributed to A M de Almeida.

At least 19 recordsLinked to original sources
PubMed2001

Determination of molybdenum in steel by adsorptive stripping voltammetry in a homogeneous ternary solvent system.

A new alternative approach for the determination of molybdenum in steel is proposed, using adsorptive stripping voltammetry (AdSV). The determinations are performed in a homogeneous ternary solvent system (HTSS) composed of N,N-dimethylformamide, ethanol and water, with alpha-benzoinoxime (alpha BO) as the complexing agent and a sodium acetate-acetic acid buffer as the support electrolyte. The HTSS composition was optimized by mixture design modelling. The AdSV measurements were performed in the differential pulse mode using an accumulation potential of -1050 mV. Under these optimized experimental conditions, the Mo(VI)-alpha BO reduction current peak potential is observed at potentials near -1250 mV, much lower than those usually reported, and the calibration plot follows the polynomial equation I = 0.359 + 0.265 [CMo(VI)] - 0.015 [CMo(IV)]2 (r2 = 0.997), for Mo concentrations up to 10.0 micrograms L-1. There is a linear range in this calibration plot for Mo(VI) concentrations up to 0.20 microgram L-1, defined by the equation I = 0.353 + 0.385 [CMo(VI)] (r2 = 0.980). In both cases, I is the absolute value for the current in microA and CMo(VI) is the concentration of Mo in microgram L-1. The detection limit for this linear concentration range was estimated as 20 pg L-1. A RSD of 0.43% is associated with the signals at a Mo(VI) level of 0.72 microgram L-1. From the common method-interfering species tested, only iron at Fe/Mo(VI) ratios above 500 and vanadium and tungsten at M/Mo(VI) ratios above 100 appear to affect the analytical response significantly. Phosphorous may also reduce the analytical signal at P/Mo(VI) ratios above 100, due to the formation of the competitive P-Mo complex. The suggested routine procedure was tested by analyzing four stainless steel samples and the results compared well with the ICP-AES measurements. The higher sensitivity of this method permits direct determination of Mo(VI) in steels, eliminating the need of analyte concentration or separation steps in the sample processing procedure.

Journal Article↗
PubMed1999

Predictive capacity of carbamazepine pharmacokinetic parameters in a Portuguese outpatient population.

The individualization of anticonvulsant therapy regimens can contribute to the implementation of appropriate carbamazepine (CBZ) maintenance doses in epileptic patients. An accurate method for the prediction of concentrations based on a determination of parameters and serum concentrations could be of clinical relevance in the management of epilepsy. In this study, we retrospectively evaluated the predictive performance in an adult outpatient population of six different methods, representing six sets of CBZ pharmacokinetic parameters selected according to the literature using a Bayesian computer program (PKS System; Abbott Laboratories, Abbott Park, IL, USA). The study involved 50 patients with two or more available concentrations selected under several inclusion criteria. The patients were taking CBZ (between 200 and 1600 mg/d) in monotherapy or polytherapy regimens and had no hepatic or renal disease. Steady state concentrations were predicted according to the use of prior information and using one and two feedback patient concentrations. Accuracy and precision were assessed by mean prediction error (ME), mean squared prediction error (MSE) and root mean squared prediction error (RMSE). The analysis showed CL = 0.067 L/hour/kg and Vd = 1.19 L/kg as the most accurate and precise set of pharmacokinetic parameters, presenting the highest percentage of clinically acceptable estimates (error < 2 microg/mL). Additionally, predictions based on one measured feedback concentration were found to be more accurate and precise than prior population-based predictions; the use of two previous patient concentrations further improved predictive capacity but failed to show a significant difference when compared with predictions based on one measured feedback concentration. In conclusion, the adoption of the previously mentioned set of parameters as population estimates and the use of at least one feedback concentration through the Bayesian approach seems to be essential for a better CBZ use in clinical practice. Finally, despite the obtained results, we believe that the Portuguese pharmacokinetic parameter determination of antiepileptics should be carried out to improve the rationale and cost-effectiveness of anticonvulsant therapy.

Adolescent↗
PubMed1996

[Nursing research and positivism].

The authors discuss positivism foundations; the most remarkable influences to comtian's philosophy structuration; how Comte's ideas, as doctrine in so far as method, dominate society's thoughts, passing beyond XIX century and reaching XX century; and how the positivist doctrine and empirical method influenced Nursing conceptions about science and about human being/environment/disease.

Brazil↗
PubMed1994

Fetal death from syphilis: an epidemiologic evaluation in Ribeirão Preto, Brazil.

An epidemiologic study was done of five Ribeirão Preto women whose pregnancies ended in fetal death from syphilis at the University Hospital of the Ribeirão Preto Medical School, São Paulo, in 1991. The study sought to establish the epidemiologic profiles of these women, determine the prenatal care they had received, assess the risk factors involved, and propose strategies for controlling syphilis during pregnancy within the region. Data were collected through home interviews with the study subjects. Obstetric (maternal and fetal) information obtained from these interviews was subsequently verified by consulting the women's medical records. In all, some 25 problems with a bearing on the fetal deaths were found, these being ascribable in roughly equal measure to health system shortcomings and the study subjects' knowledge and behavior. Notable among the health system problems were delayed receipt of serologic findings, failure to comply with recommended routines, late medical diagnosis, and ineffective monitoring of cure. Principal patient-related problems included ignorance of syphilis and unawareness of the importance of prenatal care. In view of the fact that fetal death from syphilis continues to occur in the affected region, it is recommended that maternal and child health authorities seek to establish or reestablish prenatal care of the requisite quality by instituting clear-cut guidelines for serologic screening, implementation of epidemiologic surveillance, and effective action by medical and paramedical teams.

Adult↗
PubMed1993

Chromosomal irp2 gene in Yersinia: distribution, expression, deletion and impact on virulence.

Iron starvation induces the synthesis of two high molecular weight proteins (HMWP1 and 2) in Yersinia. The presence of the irp2 gene coding for the HMWP2 was investigated in 170 Yersinia strains. This gene was absent from all avirulent or weakly pathogenic species and was restricted to highly pathogenic strains. One hundred percent of the potentially highly pathogenic Yersinia enterocolitica biotype 1B harbored irp2 but surprisingly, 70.4% of the Yersinia pseudotuberculosis tested lacked the gene. Only serotypes I and III of Y. pseudotuberculosis harbored the locus, however, synthesis of HMWPs was detected uniquely in the former. In Yersinia pestis, overall 55.3% of the strains tested had the gene, with an uneven distribution among Orientalis (65.2%), Antiqua (66.6%) and Medievalis (0%) geographic variants. Except for one Y. pestis strain, the irp2 restriction profiles were identical for all strains of Y. pestis and Y. pseudotuberculosis tested. All Y. enterocolitica 1B displayed the same irp2 pattern, different from that of the other two species. In vitro spontaneous deletion of irp2 was not obtained in Y. enterocolitica 1B but was observed in both Y. pseudotuberculosis and Y. pestis. Repeated subcultures of Y. pestis increased progressively the proportion of irp2-deleted colonies, yielding an almost pure irp2-deleted strain after 16 subcultures. A clear correlation was established between the presence of irp2 and the level of virulence of Y. pseudotuberculosis and Y. pestis.

Animals↗
PubMed1993

Relationship between loss of pigmentation and deletion of the chromosomal iron-regulated irp2 gene in Yersinia pestis: evidence for separate but related events.

The irp2 gene, coding for a 190-kDa iron-regulated protein (HMWP2), and the hemin storage locus (hms), which determines Yersinia pestis pigmentation, are each located on a large chromosomal fragment which carries virulence genes and deletes spontaneously. To determine whether the two loci are located on one unstable fragment or on two different excisable DNA segments, the pigmentation status and the presence of irp2 in 43 strains of Y. pestis isolated in various parts of the world were examined. Three different types were observed: Pgm+ Irp2+ (39.5%), Pgm- Irp2- (44.2%), and Pgm- Irp2+ (16.3%). No Pgm+ Irp2- strain was found. These three types were also recovered in vitro from the parental strain Saigon 55-12-39 (Pgm+ Irp2+), but again, no Pgm+ Irp2- colony was observed. Pgm- Irp2- derivatives were obtained from a single Pgm- Irp2+ colony, indicating sequential loss of the two traits. The fact that the genomic SpeI restriction patterns obtained by pulsed-field gel electrophoresis were specific for each of the three variants suggested that distinct large-scale chromosomal rearrangements had occurred in the Pgm- Irp2+ and Pgm- Irp2- derivatives. The virulence of Pgm- Irp2+ bacteria in mice was ca. 10(7)-fold lower than that of the Pgm+ Irp2+ strains injected subcutaneously but was not significantly decreased when injected intravenously. In contrast, the Pgm- Irp2- microorganisms were markedly less pathogenic (10(6)-fold) than the Pgm+ Irp2+ strains injected intravenously and were 100 times less virulent than the Pgm- Irp2+ strains injected subcutaneously.

Animals↗
PubMed1993

Renal transplantation in leprosy patients.

We report four cases of leprosy in renal transplant recipients, two of whom had the disease before transplantation and no signs of relapse even in the presence of immunosuppressive drugs. The other two cases presented with lepromatous and borderline (dimorphous) leprosy 5 months and 5 years after transplantation, respectively. The disease of the last patient was controlled with sulfone even in the presence of immunosuppressive drugs, but the mechanism whereby the first patient rapidly developed lepromatous leprosy is unclear, even though he was a home contact of a patient with lepromatous leprosy (his wife). In view of the data presented here, we do not contraindicate renal transplantation in patients with leprosy who frequently suffer changes in renal function. We believe that renal function should be periodically evaluated in patients with borderline and lepromatous leprosy.

Adult↗
PubMed1984

Side-to-side choledochoduodenostomy in the management of choledocholithiasis and associated disease. Facts and fiction.

Ascending cholangitis, the sump syndrome, and alkaline reflux gastritis are drawbacks commonly ascribed to side-to-side choledochoduodenostomy. Most surgeons consider side-to-side choledochoduodenostomy as a last resort measure to be utilized only in elderly patients and only on ducts wider than 15 mm. In trying to assess the pertinence of such alleged inconveniences and limitations, a series has been analyzed (retrospectively until 1976 and prospectively from then on). A total of 70 of these operations were performed from January 1973 to September 1982, on 53 women and 17 men. Twenty-six percent were less than 50 years of age, and 30 percent were over 70 years of age. Sixteen of the 70 operations were reoperations that took place several years after cholecystectomy. Intravenous cholangiographic films were obtained preoperatively for evaluation of the duct width which was less than 15 mm in 23 patients (33 percent). The follow-up period, surpassing 2 years in 35 patients (50 percent), includes clinical interviews and liver biochemistry measurements every 6 months, and endoscopic retrograde cholangiopancreatography 12 to 18 months postoperatively. There was one postoperative death (1.4 percent), and significant morbidity developed in five patients (7.1 percent). The postoperative hospital stay averaged 8 days. The long-term results were classified as excellent in 50 patients, good in 15 patients, fair in 3 patients, and poor in 1 patient. Side-to-side choledochoduodenostomy is a safe, very effective therapeutic measure, even when performed on ducts less than 15 mm wide, provided a few technical requirements are respected. It does not carry the inconveniences that have usually been ascribed to it. The excellent long-term results in the present series have allowed us to liberalize its utilization, especially in young patients.

Aged↗
PubMed1982

Definitive decompression of the biliary tree-preferred approach to management of choledocholithiasis and/or associated pathology.

The experience of the senior author in the management of biliary tract lithiasis and/or associated pathology is analyzed, retrospectively until 1976 and prospectively from then on, in an attempt to ascertain the most efficient manner of handling a duct requiring surgical exploration. Primary surgery was done on 245 patients, while 22 common bile duct reoperations were carried out on 20 patients. In the primary surgery group, 177 simple cholecystectomies were undertaken, and an indication for duct exploration was present in the other 68. Out of 90 common bile duct explorations, 68 primary ones plus 22 reoperations, two operative deaths occurred (one in each group). Fifteen patients had a choledocholithotomy with temporary T-tube decompression, with "normal' postexploratory and predischarge tube cholangiograms. Six of these (40%) required reoperation (recurrent stones in three, residual calculus in two, stenotic papilla in one). Of 70 ducts definitively drained (60 choledochoduodenostomies, nine sphincteroplasties, one Y-loop hepaticojejunostomy) only one (1.4%) of the patients who had a sphincteroplasty has had an episode of jaundice and cholangitis, a highly significant difference (p = 0.001). This experience suggests that a correct biliary fenestration, permanently decompressing the biliary tree, performed during the initial operation will avoid many unnecessary hospital admissions and should, therefore, be seen as the procedure of choice in the overwhelming majority of situations when a pathological common bile duct is encountered.

Adult↗
PubMedDate not supplied

Plasmid composition and virulence-associated factors of Yersinia pestis isolates from a plague outbreak at the Paraiba State, Brazil.

Pathogenic Yersinia pestis isolates were collected during a plague outbreak at the Paraiba State in 1986. The Y. pestis isolates were investigated for the presence of virulence-associated factors and plasmid content. All strains analysed were proficient in the expression of the VW and fraction 1 antigens, pigment adsorption and pesticin-fibrinolysin-coagulase production. A similar plasmid profile composed by four plasmid with molecular weight of 60, 44, 14.9, and 6.4 Megadaltons (MD) was found in all strains. DNA cleavage with EcoRI restriction enzyme further demonstrated the uniform plasmid content of the Y. pestis isolates. Seven additional Y. pestis strains, previously isolated in the same region but in an endemic state, showed the same plasmid fingerprint. The lack of any detectable difference between epidemic and endemic isolates as well as the value of plasmid fingerprints in epidemiology of Y. pestis is discussed.

Animals↗
PubMedDate not supplied

Plague surveillance in Brazil: 1983-1992.

Plague caused by Yersinia pestis, has persisted in Brazil in several natural foci spread throughout rural areas in the States of Ceara, Paraiba, Pernambuco, Piaui, Rio Grande do Norte, Alagoas, Bahia, Minas Gerais and Rio de Janeiro. Nationwide surveillance of plague in Brazil based on serological testing started in 1983. We now present an update report of the examinations carried out in our laboratory from 1983 to 1992. The passive hemagglutination test for antibodies against fraction 1A antigen of Y. pestis and the passive hemagglutination inhibition control were employed for testing a total of 220,769 sera. Samples analyzed included 2,856 sera from clinically diagnosed plague cases or suspects, 49,848 sera from rodents of 24 species and 2 species of small wild carnivores (marsupials), 122,890 sera from dogs, and 45,175 sera from cats. Specific antibodies were found in 92 (3.22%) human sera; 143 (0.29%) sera from rodents of 8 species and from the two species of marsupials, 1,105 (0.90%) sera from dogs and 290 (0.64%) sera from cats. The presence of significant levels of specific anti-F1A antibodies among rodents and wild or domestic carnivores (dogs and cats) indicates that all the Brazilian plague foci remain active in spite of the absence of human cases in some of them.

Animals↗
PubMedDate not supplied

A simple PCR-based procedure for plague diagnosis.

Supernatant of boiled spleen saline-suspensions of Yersinia pestis experimentally infected animals were used as template for PCR amplification without DNA extraction. PCR sensitivity was enhanced by a second round of amplification (Nested). No amplification was observed from non-infected animals.

Animals↗
PubMedDate not supplied

[Natural infection by Yersinia pestis, in fleas from plague foci in the northeast of Brazil].

Three different containment transport processes of fleas were evaluated as an approach to the bacteriologic isolation of Yersinia pestis. The three methods employed were: live fleas in glass tubes containing pieces of wrapped filter paper; dead fleas in saline solution; and macerated fleas in Cary-Blair culture medium. The two latter methods were almost equal and superior to the first method. A total of 29512 flea pools, from plaque foci in Northeast Brazil collected during 1966 to 1982 were evaluated by the three methods. Among these samples, 236 (0.80%) flea pools were positive with regard to bacteriological cultivation and/or infection of susceptible animals.

Animals↗
PubMedDate not supplied

[The absence of Yersinia enterocolitica in foods and animal reservoirs in areas of the state of Pernambuco, Brazil].

A search for the presence of enteropathogenic bacteria in fresh vegetables obtained in 5 restaurants from the city of Recife, revealed neither Yersinia enterocolitica nor other pathogenic bacteria in 96 samples analyzed. Furthermore, Y. enterocolitica was not found in the oral and rectal swabs taken from 15 apparently healthy pigs at an abattoir in the municipality of Bonito in the Pernambuco State. Another search in which twenty one rodents from four species and one marsupial specimen were examined did not detect the presence of Yersinia and other enteropathogenic bacteria.

Abattoirs↗