Synchronous scanning phosphorimetry for the selective determination of chrysene: a metrological study

Room-temperature phosphorimetry was used to quantify trace levels of chrysene in sugar-cane spirits and in fish bile. A selective phosphorescence enhancer (AgNO3) and synchronous scanning allowed the detection of ng amounts of chrysene. Accuracy (113 ± 17%) and selectivity was evaluated using the CRM-NIST-1647d - Priority Pollutant Polycyclic Aromatic Hydrocarbons in acetonitrile. Analysis of sugar-cane spirit samples enabled recovery of 108 ± 18% which agreed with the one achieved using HPLC. Method's uncertainty was equivalent to 3.4 ng of the analyte, however, the analyte pre-concentration (SPE) improved sensibility and minimized the relative uncertainty. Characterization and homogeneity studies in fish bile were also performed.

Enhancing longevity of pacemakers through reprogramming. Underutilization and cost-effectiveness

OBJECTIVE: This study was performed to observe the number of pacemakers that had never been reprogrammed after implantation, and the effect of optimised output programming on estimated longevity of pulse generators in patients with pacemaker METHODS: Sixty patients with Teletronics Reflex pacemakers were evaluated in a pacemaker clinic, from the time of the beginning of its activities, in June 1998, until March 1999. Telemetry was performed during the first clinic visit, and we observed how many pulse generators retained nominal output settings of the manufactures indicating the absence of reprogramming until that date. After evaluation of the capture threshold, reprogramming of pacemakers was performed with a safety margin of 2 to 2.5:1, and we compared the estimated longevity based on battery current at the manufacturer's settings with that based on settings achieved after reprogramming. RESULTS: In 95% of the cases, the original programmed setting was never reprogrammed before the patients attended the pacemaker clinic. Reprogramming the pacemaker prolonged estimated pulse generator life by 19.7±15.6 months (35.5%). CONCLUSION: The majority of the pacemakers evaluated had never been reprogrammed. Estimated pulse generator longevity can be prolonged significantly, using this simple, safe, efficacious, and cost-effective procedure.

Time course of in vitro maturation of intra-erythrocytic malaria parasite: a comparison between Plasmodium falciparum and Plasmodium knowlesi

The schizont maturation assay for in vitro drug sensitivity tests has been a standard method employed in the global baseline assessment and monitoring of drug response in Plasmodium falciparum. This test is limited in its application to synchronous plasmodial infections because it evaluates the effect of drug on the maturation of parasite especially from ring to schizont stage and therefore synchronized P. falciparum cultures are required. On the other hand, P. knowlesi, a simian malaria parasite has a unique 24-h periodicity and maintains high natural synchronicity in monkeys. The present report presents the results of a comparative study on the course of in vitro maturation of sorbitol synchronized P. falciparum and naturally synchronous P. knowlesi. Ring stage parasites were incubated in RPMI medium supplemented with 10-15% pooled homologous serum in flat-bottomed 96-well micro plates using a candle jar at 37°C. The results suggest that the ideal time for harvesting the micro-assay plates for in vitro drug sensitivity test for sorbitol-synchronized P. falciparum and naturally synchronous P. knowlesi are from 26 to 30 h and from 22 to 25 h, respectively. The advantages of using P. knowlesi in chemotherapeutic studies are discussed.

Ultrasound monitoring of structural urinary tract disease in Schistosoma haematobium infection

A major advance in our understanding of the natural history of Schistosoma haematobium-related morbidity has come through the introduction of the portable ultrasound machines for non-invasive examination of the kidneys and bladder. With the use of generators or battery packs to supply power in non-clinical field settings, and with the use of instant photography or miniaturized thermal printers to record permanent images, it is possible to examine scores of individuals in endemic communities every day. Broad-based ultrasound screening has allowed better definition of age-specific disease risks in urinary schistosomiasis. Results indicate that urinary tract abnormalities are common (18% overall prevalence) in S. haematobium transmission areas, with a 2-4% risk of either severe bladder abnormality or advanced ureteral obstruction. In longitudinal surveys, ultrasound studies have shown that praziquantel and metrifonate therapy are rapidly effective in reversing urinary tract abnormalities among children. The benefits of treating adults are less well known, but research in progress should help to define this issue. Similarly, the prognosis of specific ultrasound findings needs to be clarified, and the ease of sonographic examination will make such long-term follow-up studies feasible. In summary, the painless, quick, and reproducible ultrasound examination has become an essential tool in the study of urinary schistosomiasis.

A Pedagogical approach of schistosomiasis an experience in health education in Minas Gerais, Brazil

The experience described here is part of an extensive program that aims to stimulate schools to develop health integrated projects from theme generators, i.e., themes that have a meaning for the community. It was developed in Jaboticatubas, a town in the metropolitan region of Belo Horizonte, capital of the state of Minas Gerais, Brazil, and the focus was schistosomiasis. The selection was based on the expressive and historical prevalence of this disease in the county, which has been known as the "capital of schistosomiasis", in a national press release since the 1960's. Schistosomiasis is also a theme pointed out by teachers as requiring more information and methodologies to work with their students, most of them living in areas of high risk of transmission. In addition, during the last years, this disease has been transmitted silently through an increasing rural tourism in that region, requiring integrated and effective control actions. The developed strategy included four schools, whose teachers, students, and families took part in the process. It emphasizes in a critical pedagogy approach, which focuses on health issues as themes that may mobilize the school community and awake the population to a work which integrates environment, health, and citizenship. The results demonstrate that teachers and students not only acquired new knowledge and methodological skills, but also gained confidence in their ability to improve their health conditions. Thus, the project promotes a critical education that can result a more permanent effect on the control of schistosomiasis as well as other benefits for the schools and for the population.

A micro-spreading improvement for spermatogenic chromosomes from Triatominae (Hemiptera-Reduviidae)

Cytogenetics of triatomines have been a valuable biological tool for the study of evolution, taxonomy, and epidemiology of these vectors of Trypanosoma cruzi. Here we present a single microtube protocol that combines micro-centrifugation and micro-spreading, allowing high quality cytogenetic preparations from male gonadal material of Rhodnius prolixus and Triatoma lecticularia. The amount of cellular scattering can be modulated, which can be useful if small aggregates of synchronous cells are desired. Moreover, a higher number of slides per gonad can be obtained with fully flattened clean chromosomal spreads with minimum overlaps, optimal for classical and modern molecular cytogenetic analyses.

Interfase y software de control para operar en sincronismo un automuestreador y un atomizador electrotérmico por filamento de tungsteno en espectrofotometría de absorción atómica

The interface and software for synchronous control of an autosampler and an electrothermal tungsten coil atomizer in atomic absorption spectrophotometry were developed. The control of the power supply, the trigger of the Read function of the spectrophotometer and the automatic operation of the autosampler was performed by software written in "TurboBasic". The system was evaluated by comparison of the repeatability of peak-height absorbances obtained in the atomization of lead by consecutive 10-µl injections of solutions (prepared in 0.2% v/v HNO3) using autosampler and manual sample introduction, and also by long term operation.

Utilização de endoperóxidos de derivados de naftaleno como fontes químicas de oxigênio singlete em sistemas biológicos

Molecular oxygen, in the first excited state (singlet oxygen, ¹O2), has a substantial reactivity towards electron-rich organic molecules, such as biological targets, including unsaturated fatty acids, proteins, RNA and DNA. Considering the complexity of biological systems and the great variety of reactive species generated by photochemistry, efforts have been devoted to develop suitable ¹O2 generators based on the thermolysis of water soluble naphthalene endoperoxides. These compounds are chemically inert and have been employed as versatile sources of ¹O2. The synthesis is based on structural modifications in position 1,4 of dimethylnaphtalene, grafting hydrophilic substituents. The correspondent endoperoxide can be generated using photochemical method, or molybdate-catalyzed disproportionation of hydrogen peroxide.

Flow analysis by using solenoid valves for As(III) determination in natural waters by an on-line separation and pre-concentration system coupled to a tungsten coil atomizer

A flow system coupled to a tungsten coil atomizer in an atomic absorption spectrometer (TCA-AAS) was developed for As(III) determination in waters, by extraction with sodium diethyldithiocarbamate (NaDDTC) as complexing agent, and by sorption of the As(III)-DDTC complex in a micro-column filled with 5 mg C18 reversed phase (10 µL dry sorbent), followed by elution with ethanol. A complete pre-concentration/elution cycle took 208 s, with 30 s sample load time (1.7 mL) and 4 s elution time (71 µL). The interface and software for the synchronous control of two peristaltic pumps (RUN/ STOP), an autosampler arm, seven solenoid valves, one injection valve, the electrothermal atomizer and the spectrometer Read function were constructed. The system was characterized and validated by analytical recovery studies performed both in synthetic solutions and in natural waters. Using a 30 s pre-concentration period, the working curve was linear between 0.25 and 6.0 µg L-1 (r = 0.9976), the retention efficiency was 94±1% (6.0 µg L-1), and the pre-concentration coefficient was 28.9. The characteristic mass was 58 pg, the mean repeatability (expressed as the variation coefficient) was 3.4% (n=5), the detection limit was 0.058 µg L-1 (4.1 pg in 71 µL of eluate injected into the coil), and the mean analytical recovery in natural waters was 92.6 ± 9.5 % (n=15). The procedure is simple, economic, less prone to sample loss and contamination and the useful lifetime of the micro-column was between 200-300 pre-concentration cycles.

Análise de fluorescência de substâncias húmicas extraídas da água, solo e sedimento da Lagoa dos Patos - MS

The humic substances were extracted from sediments, water and soil close to the Lagoa dos Patos-MS. The characterization was performed through fluorescence emission. In the HSs it is possible to see strong indications of incorporation of compounds originating from lignin degradation, confirmed by fluorescence emission (EEM and synchronous spectra). These differences observed in HSs may be due to tropical regions displaying a great variety of vascular plants and aquatic macrophytes that contribute natural organic matter. The seasonality effect also causes the entrance of pedogenic material and the suspension of sediments by the action of winds.

Direct determination of calcium in milk by atomic absorption spectrometry using flow-injection analysis

A flow-injection system with sample and reagent addition by the synchronous merging zones approach for calcium determination in milk by flame AAS is proposed. Main parameters were optimized using a factorial design with central point. The optimum conditions were 2.5% (m/v) for La concentration, 8 mL min-1 for the carrier flow-rate, 20 cm for coiled reactor and 250 ìL for sample volume. Different sample preparation procedures were evaluated such as dilution in water or acid and microwave-assisted decomposition using concentrated or diluted acids. The optimized flow system was applied to determine Ca in eleven commercial milk samples and two standard reference materials diluted in water. Similar calcium levels were encountered comparing the results obtained by the proposed method (dilution in water) with those obtained using microwave-oven digestion. Results obtained in two standard reference materials were in agreement at 95% confidence level with those certified. Recoveries of spiked samples were in the 93% - 116% range. Relative standard deviation (n = 12) was < 5.4% and the sample throughput was 150 measurements per hour, corresponding to a consumption of 250 µL of sample and 6.25 mg La per determination.

FLOWERING AND POLLINATORS OF THREE DISTYLOUS SPECIES OF Psychotria (Rubiaceae) CO-OCCURRING IN THE BRAZILIAN ATLANTIC FOREST1

ABSTRACT This study investigates the flowering and pollinators of the floral morphs of three co-occurring distylous species, Psychotria conjugens Müll, P. hastisepala Müll. Arg. and P. sessilis Vell., in two consecutive flowering seasons in an Atlantic Forest fragment in southeastern Brazil. The species have diurnal, cream-colored, tubular, nectariferous flowers and their flowering occurs in the rainy season, from September to April, with little or no overlapping between species, characterizing a staggered flowering. The flowering of the long-and short-styled floral morphs of each species was synchronous, but the number of open flowers per day per morph tended to vary in each flowering season. These numbers were higher in P. sessilis and P. conjugens and, probably, resulted in higher total numbers of visits on its flowers (up to 1084 visits in P. sessilis and 756 in P. conjugens), compared to that observed in P. hastisepala (up to 71). There was a higher frequency of visits to long-styled flowers of all species. The bee Ariphanarthra palpalis was a common pollinator to all species. This bee is native to Brazil, solitary, considered relatively rare and its host plants were unknown. Other native bees (Melipona spp.) also visited the flowers of the Psychotria species. The availability of flowers with similar floral features over eight months, the staggered flowering and common pollinators appear to be part of a strategy to attract floral visitors, minimizing the competition for pollinators and then favoring the legitimate pollination of these plants.

Tumor do apêndice vermiforme

Appendiceal tumors are rare and usually presented as acute appendicitis. They are incidentally discovered at an emergency surgery, in which case the decision-making is very difficult. The purpose of this report is discuss to the most appropriate management for appendiceal tumors. A retrospective analysis of one case treated at HU-UEL was undertaken and the literature was reviewed. The conclusion is that frozen section should be done whenever the appendiceal findings are atypical. For appendiceal carcinoids greater than 2 cm and adenocarcinomas, a right hemicolectomy is recommended. Appendectomy is apropriate for patients whose carcinoid tumors are 1 cm in diameter or less and for carcinoid tumors between 1 cm and 2 cm without extensive lymphatic permeation and mesenteric invasion. Every case should be searched for synchronous tumors.

Wind tunnel simulation of atmospheric boundary layer flows

The present work shows how thick boundary layers can be produced in a short wind tunnel with a view to simulate atmospheric flows. Several types of thickening devices are analysed. The experimental assessment of the devices was conducted by considering integral properties of the flow and the spectra: skin-friction, mean velocity profiles in inner and outer co-ordinates and longitudinal turbulence. Designs based on screens, elliptic wedge generators, and cylindrical rod generators are analysed. The paper describes in detail the experimental arrangement, including the features of the wind tunnel and of the instrumentation. The results are compared with experimental data published by other authors and with naturally developed flows.

Gender effects on esophageal motility

It has been suggested that there are no gender effects on esophageal motility. However, in previous studies the subjects did not perform multiple swallows and the quantitative features of esophageal contractions were not evaluated. In order to investigate the gender effects on esophageal motility we studied 40 healthy normal volunteers, 20 men aged 37 ± 15 years (mean ± SD), and 20 women aged 38 ± 14 years. We used the manometric method with an eight-lumen polyvinyl catheter and continuous perfusion. The upper and lower esophageal sphincter pressures were measured by the rapid pull-through method. With the catheter positioned with one lumen opening in the lower esophageal sphincter, and the others at 5, 10 and 15 cm above the sphincter, ten swallows of a 5-ml water bolus alternated with ten dry swallows were performed. Statistical analysis was done by the Student t-test and Mann-Whitney test. Gender differences (P<0.05) were observed for wet swallows in the duration of contractions 5 cm above the lower esophageal sphincter (men: 3.7 ± 0.2 s, women: 4.5 ± 0.3 s, mean ± SEM), and in the velocity of contractions from 15 to 10 cm above the lower esophageal sphincter (men: 4.7 ± 0.3 cm/s, women: 3.5 ± 0.2 cm/s). There was no difference (P>0.05) in sphincter pressure, duration and percentage of complete lower esophageal sphincter relaxation, amplitude of contractions, or in the number of failed, multipeaked and synchronous contractions. We conclude that gender may cause some differences in esophageal motility which, though of no clinical significance, should be taken into consideration when interpreting esophageal motility tests.