A multisyringe flow injection method for the automated determination of sulfide in waters using a miniaturised optical fiber spectrophotometer

In this paper, a fully software-controlled multisyringe flow injection (MSFIA) spectrophotometric system is proposed for the determination of sulfide in environmental and waste waters. The implementation of ancillary solenoid valves into the flow network allows a multitude of injection modalities to be explored, the selected modality being directly dependent on the aim of the assays. The multicommuted sandwich-type approach is introduced in this work as an efficient means to warrant high sensitivity for the particular assay with excellent repeatabilities and a considerable reagent saving. Moreover, a high injection frequency may be easily attained by carrying out a multiple injection modality during a single forward displacement of the piston driver bar. The interfacing of the robust and versatile multisyringe piston pump with an optical fiber plug-in spectrophotometer furnished with a light emitting diode enables the miniaturization of the flow analyzer, which is thus readily adaptable to in-situ and real-time monitoring schemes. The flow method is based on the coupling Fischer's reaction of sulfide with N,N-dimethyl-p-phenylenediamine in the presence of Fe(III) as oxidizing reagent in a 0.7M HCl medium. Careful selection of the physical and chemical variables enabled coefficients of variations better than 1.5% (n = 10) at the 1mgl(-1) level for both injection modalities. Dynamic working ranges of 0.2-2.0 and 0.5-5mgl(-1) sulfide for sandwich and multiple injection techniques, and detection limits of 0.09 and 0.15mgl(-1), respectively, were obtained. Furthermore, the sandwich modality featured an average slope of 0.43 +/- 0.02lmg(-1) calculated from 10 day-to-day calibration plots. This result reveals better sensitivity than other flowing stream methods described in the literature. The multiple injection technique allowed an improvement of the injection throughput up to 80h(-1), although a decrease of sensitivity was concomitantly observed (average slope of 0.17 +/- 0.01lmg(-1)). The multisyringe flow method was successfully applied to the determination of sulfide in different spiked water matrices (namely, mineral, tap, freshwater, seawater and wastewater) with recoveries ranging from 96 to 104%. Good agreement was also found in water samples between the MSFIA results and those of the batch APHA-standard method.

Automated system for on-line determination of dimethylarsinic and inorganic arsenic by hydride generation-atomic fluorescence spectrometry

A multisyringe flow-injection approach has been coupled to hydride generation-atomic fluorescence spectrometry (HG-AFS) with UV photo-oxidation for dimethylarsinic (DMA), inorganic As and total As determination, depending on the pre-treatment given to the sample (extraction or digestion). The implementation of a UV lamp allows on-line photo-oxidation of DMA and the following arsenic detection, whereas a bypass leads the flow directly to the HG-AFS system, performing inorganic arsenic determination. DMA concentration is calculated by the difference of total inorganic arsenic and measurement of the photo-oxidation step. The detection limits for DMA and inorganic arsenic were 0.09 and 0.47 μg L(-1), respectively. The repeatability values accomplished were of 2.4 and 1.8%, whereas the injection frequencies were 24 and 28 injections per hour for DMA and inorganic arsenic, respectively. This method was validated by means of a solid reference material BCR-627 (muscle of tuna) with good agreement with the certified values. Satisfactory results for DMA and inorganic arsenic determination were obtained in several water matrices. The proposed method offers several advantages, such as increasing the sampling frequency, low detection limits and decreasing reagents and sample consumption, which leads to lower waste generation.

[HIV PREVENTION FOR HISPANIC WOMEN FIFTY YEARS AND OLDER.]

INTRODUCTION

Hispanic women aged 50 and over (OHW) are a minority in the U.S. at high risk of acquiring HIV and the least studied group of population in relation to health, social characteristics and sexual behavior.

OBJECTIVE

To investigate the factors that increase HIV risk among OHW with the purpose of developing or adapting an intervention appropriate for their "age and culture".

METHODOLOGY

A cross-sectional descriptive study with a sample of 50 OHW, sexually active and who residing in Miami, Florida, U.S. A structured questionnaire was administered by trained bilingual interviewers (English/Spanish). Participants were recruited from different locations in South Florida. Data were analyzed using descriptive statistics, including central tendency and dispersion measures.

RESULTS

OHW's mean age was 55.7 ± 6 years old (range 50-76 years old). All the OHW were in the menopause.

HIV PREVENTION

OHW reported average levels of HIV knowledge and partner communication. In the sample OHW reported depression symptoms, intimate partner violence, negative attitudes towards people living with HIV and low perceived risk of acquiring HIV. OHW mentioned learning needs in topics related to HIV prevention and age changes.

CONCLUSION

OHW are at risk of acquiring HIV and they have special needs in terms of HIV prevention.

Directions for the diagnosis, clinical staging, treatment and prevention of canine leishmaniosis

Canine leishmaniosis (CanL) due to Leishmania infantum is a life threatening zoonotic disease with a wide distribution in four continents and importance also in non-endemic regions. The purpose of this report is to present a consensus of opinions on the diagnosis, treatment, prognosis and prevention of CanL in order to standardize the management of this infection. CanL is a disease in which infection does not equal clinical illness due to the high prevalence of subclinical infection among endemic canine populations. The most useful diagnostic approaches include serology by quantitative techniques and PCR. High antibody levels are associated with severe parasitism and disease and are diagnostic of clinical leishmaniosis. However, the presence of lower antibody levels is not necessarily indicative of disease and further work-up is necessary to confirm CanL by other diagnostic methods such as cytology, histopathology and PCR. We propose a system of four clinical stages, based on clinical signs, clinicopathological abnormalities and serological status. Suitable therapy and expected prognosis are presented for each of the stages. The combination of meglumine antimoniate and allopurinol constitutes the first line pharmaceutical protocol. However, although most dogs recover clinically after therapy, complete elimination of the parasite is usually not achieved and infected dogs may eventually relapse. Follow-up of treated dogs with blood counts, serum biochemistry, urinalysis, serology and PCR is essential for prevention of relapses. Protection against sand fly bites by topical insecticides is effective in reducing infection, and recent development of vaccines has indicated that prevention by vaccination is feasible.

PCR survey of vectorborne pathogens in dogs living in and around Barcelona, an area endemic for leishmaniasis

Blood samples from 153 dogs living in and around Barcelona were assayed for Leishmania infantum and Ehrlichia, Anaplasma, Rickettsia, Bartonella, Hepatozoon, Babesia and Theileria species by PCR amplification of DNA, and the amplicons obtained were sequenced. The prevalence of the infectious agents was L infantum (29.4 per cent), Ehrlichia and Anaplasma species (4.0 per cent), Hepatozoon canis (3.3 per cent), Babesia canis vogeli (2.0 per cent), Babesia gibsoni (2.0 per cent), Babesia canis canis (1.3 per cent) and Theileria annae (0.7 per cent). Coinfections were present in seven of the dogs and they were significantly associated with L infantum infection (P=0.024). There was a significant correlation between clinical signs of illness and the load of L infantum.

Immunohistologic diagnosis of avian listeriosis

Listeriosis in a chicken from a small farm was diagnosed by the per-oxidase-antiperoxidase (PAP) method. The animal had diffuse myocarditis and necrotic foci in the liver and in the spleen. PAP technique performed on formalin-fixed tissues confirmed the presumptive diagnosis. Serological and microbiological studies were also done. It is concluded that PAP method is useful for the diagnosis of avian listeriosis allowing retrospective studies with formalin-fixed, paraffin-embedded tissues, avoiding cumbersome microbiological culture.

Cutaneous mucinosis in shar-pei dogs is due to hyaluronic acid deposition and is associated with high levels of hyaluronic acid in serum

Cutaneous mucinosis affects primarily shar-pei dogs. Hyaluronic acid (HA) is considered to be the main component of mucin and CD44 is the major cell surface receptor of HA, necessary for its uptake and catabolism. The aims of this study were to identify the composition of the mucin in cutaneous mucinosis of shar-pei dogs, investigate the correlation between the deposition of HA and the expression of CD44, and determine whether shar-pei dogs with cutaneous mucinosis presented with elevated levels of serum HA. In skin biopsies, the mucinous material was stained intensely with Alcian blue and bound strongly by the hyaluronan-binding protein. No correlation was found between the degree of HA deposition in the dermis and the expression of CD44 in the skin of shar-pei dogs affected or unaffected by cutaneous mucinosis. A clear positive correlation was found between the existence of clinical mucinosis and the serum HA concentration. In control dogs, serum HA ranged from 155.53 to 301.62 microg L(-1) in shar-pei dogs; without mucinosis it ranged from 106.72 to 1251.76 microg L(-1) and in shar-pei dogs with severe mucinosis it ranged between 843.51 to 2330.03 microg L(-1). Altogether, the results reported here suggest that mucinosis of shar-pei dogs is probably the consequence of a genetic defect in the metabolism of HA.

Immunocytochemical diagnosis of Pacheco's disease

An indirect immunoperoxidase method for the detection of herpesvirus in the liver and digestive tract of two psittacines (Ara macao and Cacatua sulphurea) with Pacheco's disease is described. The anti-Pachecovirus antiserum used was obtained from hyperimmunized specific pathogen-free chickens. It is concluded that this easily executed technique yields reliable results, allows a firm diagnosis of Pacheco's disease to be made and it would be suitable for investigating the pathogenesis of Pacheco's disease.

Simulating the migration of drifters deployed in the Bay of Biscay, during the Prestige crisis

A main conclusion following the oil spill from the Prestige tanker was that improvements in ocean circulation models were necessary; this was in order to predict, more accurately, the trajectories followed by the oil slicks and hence assist in fight against oil pollution operations. In this contribution, the results of the validation of a semi-empirical ocean circulation model, parameterised for the Bay of Biscay and forced with operational oceano-meteorological remote sensing observations, are shown. The model results have been validated with observations from drifting buoys, deployed in the Bay of Biscay during the crisis. The results show that the model explains a relatively large percentage of the current variability. The comparisons between the real and the estimated drifter trajectories indicate that for 3, 5 and 7 day-long trajectories, the drifter position is estimated with errors of approximately 23, 35 and 46km, respectively. The model reproduces relatively well the trajectory followed by the drifter with the shortest period (23 days).

Neutrophilic dermatosis resembling pyoderma gangrenosum in a dog with polyarthritis

This report describes a case of neutrophilic dermatosis in a dog, with a number of clinical and pathological similarities to human pyoderma gangrenosum. A seven-year-old, female German shepherd dog with a history of non-erosive idiopathic polyarthritis was presented with severe facial swelling, bilateral erosivoulcerative lesions on the muzzle and multiple, eroded, dermal-subcutaneous nodules on the cranial trunk. Histopathological examination of skin biopsies revealed a necrotising neutrophilic dermatitis. No infectious agents could be detected using specific stains, immunohistochemistry, serology and bacterial aerobic, anaerobic or fungal cultures. A sterile neutrophilic dermatosis resembling human pyoderma gangrenosum was presumptively diagnosed, and the patient showed an excellent response to treatment with prednisone and ciclosporin.

Evaluation of the expression of P-selectin, ICAM-1, and TNF-alpha in bacteria-free lesional skin of atopic dogs with low-to-mild inflammation

Canine atopic dermatitis (AD) is a pruritic skin condition that shares many clinical and pathophysiological features with its human counterpart. A major therapeutic challenge of AD is the control of the skin inflammatory process. A detailed knowledge of the pro-inflammatory molecules involved in cell recruitment in AD would allow for a better control of the disease. We thus have studied the protein expression of P-selectin, ICAM-1 and TNF-alpha in the lesional and non-lesional skin of atopic dogs that had been treated for bacterial infections. Despite a low-to-mild inflammatory process, P-selectin protein was clearly upregulated in the lesional skin areas when compared with non-lesional skin (four-fold average increase). This P-selectin upregulation was accompanied by signs of functional changes such as increased cell margination, and membrane-associated protein expression. Although the expression of ICAM-1 and TNF-alpha was not enhanced in the lesional versus the non-lesional skin, there was a trend towards a correlated upregulation of both molecules. Further studies will help elucidate the significance of the substantial overexpression of P-selectin in canine AD, in particular in a scenario where bacterial antigens are not contributing as pro-inflammatory stimuli.

Acute toxicities of four metals on the early life stages of the crab Chasmagnathus granulata from Bahía Blanca estuary, Argentina

Acute semistatic toxicity tests were carried out for 96 h with first zoeae and young crabs of Chasmagnathus granulata. Survival curves and LC50 (lethal concentration 50, the concentration which produces the death of 50% of the exposed population) indices for copper, zinc, cadmium, and lead were determined. Furthermore, mixture toxicity tests (Cd/Cu and Cd/Zn) with first-stage larvae were also carried out. The LC50-96 h values determined in this study were 1093.4 (881-1319) microg Pb2+ L(-1), 219.2 (188.9-248.9) microg Cu2+ L(-1), 172.1 (141.3-203.6) microg Zn2+ L(-1), and 47.8 (37.9-58.0) microg Cd2+ L(-1) for zoeae I and 130.1 (121.7-139.0) mg Cu2+ L(-1), 51.0 (41.9-61.6) mg Zn2+ L(-1), and 35.7 (30.1-41.9) mg Cd2+ L(-1) for young crabs. The LC50-96 h indices for mixture tests with zoeae I were 260.6 (227.3-286.3) microg Cd2+/Zn2+ L(-1) and 41.3 (37.4-60.7) microg Cd2+/Cu2+ L(-1). Cadmium presented the highest acute toxicity for both stages of the life cycle examined. The toxicity of the metals analyzed followed the order cadmium >zinc>copper>lead. First zoeae were more sensitive than young crabs to acute exposure to all metals analyzed. The young crabs were considered potentially dangerous agents of transference to the associated trophic chain because of their relatively elevated resistance and their capacity to bioaccumulate heavy metals in their tissues. Mixed toxicity tests carried out on first-stage larvae showed different kinds of interactions. Cadmium/copper presented an additive interaction trend while the mixture cadmium/zinc showed an antagonistic interaction.

A smart multisyringe flow injection system for analysis of sample batches with high variability in sulfide concentration

A fully automated smart multisyringe flow injection analysis (MSFIA) system for the monitoring of sulfide in a wide concentration range is proposed. It allows the determination of sulfide in samples containing suspended solids without requiring any preliminary batch sample treatment. The smart system is able to choose by itself the best approach to quantify the analyte, selecting either a spectrophotometric or a reflectometric detection. The method, carried out in a multi-commuted system, is based on the analyte release as hydrogen sulfide from the donor channel of the gas-diffusion module into an alkaline acceptor channel solution, which is merged with N,N-dimethyl-p-phenylenediamine (DMPD) and Fe(III). The in-line generated methylene blue (MB) dye can be delivered to an optical fiber diffuse reflectance sensor or to a flow-cell spectrophotometer according to the analyte concentration. The detection limit (3s(b)/S) was 4.6 microg l(-1). Two linear calibration graphs between 50-1000 and 500-10000 microg l(-1) sulfide for reflectometry and spectrophotometry, respectively, were obtained. The potentialities of this method were assessed via the determination of sulfide at a wide range of concentrations (4.6 microg l(-1) to 100 mg l(-1)). The high selectivity and sensitivity, the low reagent consumption and the miniaturization of the proposed automated method should be highlighted.

Evaluation of FDG PET in early axillary lymph node response to neoadjuvant chemotherapy in locally advanced breast cancer patients

10500

Background: Regional axillary lymph node status has remained the single most independent variable to predict prognosis both in terms of disease recurrence and survival. This study aimed to prospectively assess sequential FDG PET findings as early predictors of axillary lymph node response to neoadjuvant chemotherapy in locally advanced breast cancer patients. Methods: A total of 255 attenuation-corrected scans were obtained from 51 patients. Images were acquired with a PET/CT scanner (GE Discovery LS) following administration of FDG (5 MBq/kg) at baseline, and after the first, second, third, and sixth course of chemotherapy. Clinical examination and US were used to assess the size of axillary lymph nodes. PET data were interpreted using standardized uptake values (SUV) corrected or not for partial volume effects. Changes in the SUV were considered as surgical/histopathological responses. Results: This study focused on axillary lymph node staging, therefore, primary breast tumor data were not considered in the analysis. The sensitivity, specificity, and accuracy of axillary node staging was higher with PET (75%, 87%, 80%) than with clinical examination and US (50%, 78%, 63%, and 50%, 83%, and 65%, respectively), and even the more so when PET images were corrected for partial volume effects (86%, 83%, 84%). Significant differences between absolute FDG uptake values in responders and non-responders were observed at baseline (p < 0.05). While FDG uptake did not vary much in non-reponders, as confirmed by histopathology, it markedly decreased to baseline levels in responders (p < 10−5). Fifty percent of baseline SUV was considered the best cut-off value to distinguish responders from non-responders. The sensitivity, specificity, negative predictive value, and accuracy of FDG PET after one course of chemotherapy were respectively, 96%, 75%, 95%, and 84%. Tumor response assessment by clinical examination or US was never statistically significant whatever the cut-off. Conclusions: The pathological status of regional axillary lymph nodes in locally advanced breast cancer patients can be accurately predicted after one course of neoadjuvant chemotherapy based on FDG PET images.

No significant financial relationships to disclose.