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Biomedical subjects

A Cid

Publications and source records attributed to A Cid.

At least 19 recordsLinked to original sources
PubMed2006

Removal of triazine herbicides from freshwater systems using photosynthetic microorganisms.

The uptake of the triazine herbicides, atrazine and terbutryn, was determined for two freshwater photosynthetic microorganisms, the green microalga Chlorella vulgaris and the cyanobacterium Synechococcus elongatus. An extremely rapid uptake of both pesticides was recorded, although uptake rate was lower for the cyanobacterium, mainly for atrazine. Other parameters related to the herbicide bioconcentration capacity of these microorganisms were also studied. Growth rate, biomass, and cell viability in cultures containing herbicide were clearly affected by herbicide uptake. Herbicide toxicity and microalgae sensitivity were used to determine the effectiveness of the bioconcentration process and the stability of herbicide removal. C. vulgaris showed higher bioconcentration capability for these two triazine herbicides than S. elongatus, especially with regard to terbutryn. This study supports the usefulness of such microorganisms, as a bioremediation technique in freshwater systems polluted with triazine herbicides.

Atrazine↗
PubMed2005

Analysis and enhancement of astaxanthin accumulation in Haematococcus pluvialis.

The green microalga Haematococcus pluvialis was cultured with different concentrations of NaNO(3) to determine the effect on cell growth and astaxanthin accumulation. The optimum nitrate concentration to obtain astaxanthin and to avoid the cessation of cell division was 0.15 g/l NaNO(3). The ratio chlorophyll a/total carotenoids proved a good physiological indicator of nitrogen deficiency in the cell. The effect of different carbon sources, malonate and acetate, on astaxanthin accumulation was also studied; up to 13 times more carotenoids per cell were accumulated in cultures with malonate than in cultures without this compound. The pigment analysis was performed by a new low toxicity HPLC method capable of separating chlorophylls a and b, carotenes and xanthophylls in a short-period of time, using low volumes of solvents and with an economical price. With this method even echinenone was separated, which had been unsuccessful by any other method.

Acetates↗
PubMed2004

Development of a new disease-specific quality-of-life questionnaire to adults living with haemophilia.

A haemophilia-specific health-related quality-of-life questionnaire (named 'Hemofilia-QoL') was developed to assess quality-of-life in adults with haemophilia, and was psychometrically tested. Seventy-three interviews with haemophilia patients and health care professionals were used to generate the items included in the questionnaire, and expert ratings on the items formulated were used to screen them for potential omission. This was followed by psychometric testing in a sample of 35 patients. Preliminary psychometric testing of the revised questionnaire version, which contains 10 domains (physical health, physical role, joint damage, pain, treatment satisfaction, emotional role, mental health, social support), showed acceptable reliability (alpha = 0.94 for the Hemofilia-QoL total score) and validity, and this will be examined in a subsequent study with a larger patient sample.

Adolescent↗
PubMed2003

[GB virus C: lack of association with transaminases levels, CD4 and HIV viral load in aids patients].

OBJECTIVE: To study the prevalence of GBV-C-RNA in sera of HIV-infected patients and determine whether differences in immunological condition and hepatic disease exist between GBV-C positive and negative patients. METHODS: The presence of GBV-C-RNA was determined in sera of 222 HIV-positive patients by semi-automated RT-PCR. A comparison of GBV-C-RNA positive and negative patients was made by studying a series of clinical and analytical parameters. This same comparison was made in particular between those coinfected with HCV and GBV-C and those who only presented GBV-C. RESULTS: Prevalence of GBV-C-RNA was 28.8%. The most frequent hepatotropic virus was HCV, appearing in 71.6% of cases. Coinfection with HCV and HGV was present in 17% and 8.6% only had GBV-C. Patients positive for GBV-C-RNA showed clinical and analytical characteristics similar to those found in GBV-C-RNA negative patients. Among the HCV-GBV-C coinfected and those presenting HGV as the only virus it was observed that the coinfected group presented alterations in transaminases and predominance of parenteral transmission as a risk factor for HIV, whereas the GBV-C group presented normal transaminases and predominance of sexual transmission. No differences were perceived in mean CD4 and HIV-RNA values in both groups. CONCLUSIONS: Being positive for GBV-C in HIV-positive patients does not influence the presence of hepatic disease that in these patients is frequently accompanied by coinfection with other hepatotropic viruses. Moreover, it does not seem to influence the viremia of the HIV nor the CD4 cell counts.

Adolescent↗
PubMed2002

Physiological response of freshwater microalga (Chlorella vulgaris) to triazine and phenylurea herbicides.

The effects of two herbicides used wide-spread, isoproturon (phenylurea) and terbutryn (triazine), on growth, dry weight, elemental composition, photosynthetic pigments and protein content, and cell volume assayed by flow cytometry in the freshwater microalgae Chlorella vulgaris were studied. Different parameters for algal activity show widely different sensitivities to these aquatic pollutants. After 96 h of herbicide exposure, terbutryn was the strongest inhibitor of growth, giving an EC50 value for growth twice lower than that for isoproturon cultures (EC50 terbutryn=0.097 microM; EC50 isoproturon=0.199 microM). However, lower concentrations of the triazine herbicide provoked an increase in the cellular density and growth rate of this microalga, not observed in the phenylurea-treated cultures. Cellular volume and dry weight of C. vulgaris cells were increased strongly in the presence of isoproturon and terbutryn. Other cellular parameters, such as pigment and protein content, were stimulated with both herbicides at higher concentrations.

Adaptation, Physiological↗
PubMed2002

Orthoses in haemophilia.

In haemophilia patients, orthoses are used for the prevention and management of bleeds and their effects on the musculoskeletal system. The characteristics of these devices vary according to the joint to which they are applied, although two basic types are distinguished: static and functional. The upper limbs make up a functional unit that is adapted to prehension, or the action of grasping or seizing objects. The most affected joints of this unit in haemophilia are the elbow and shoulder, which require immobilization, followed by stabilization and protection and in the case of disability, assistance in the performance of function. The lower limbs, on the other hand, are adapted to the action of ambulation. The knee, ankle and hip joints frequently sustain damage in haemophilia, and in the acute phase they should be immobilized and the patient discouraged from walking. Once bleeding has ceased, and motion and muscle balance improved, a gradual return to normal activity may commence. The principle aim of orthotics in these cases is to immobilize and unburden the affected body segment, and to provide stability and assistance for ambulation. Shoe insoles cushion and modify stance, and therefore may help prevent lesions. Crutches and walking frames are used for restoring normal gait. Orthotic devices improve the quality of life of haemophilia patients with musculoskeletal lesions and are useful for preventing lesions resulting from strenuous activities, whether performed in the course of daily living or in the pursuit of games and sports.

Hemarthrosis↗
PubMed2000

Potential use of flow cytometry in toxicity studies with microalgae.

Cytotoxic effects of aquatic pollutants on microalgae are very heterogeneous, and they are influenced by environmental conditions and the test species. Stress produced by copper or paraquat addition to the culture medium of two microalgae was analysed by flow cytometry. Parameters assayed were: cell volume, chlorophyll a fluorescence and cell viability. The variety of results obtained in the present study reveals that flow cytometry is a useful tool in the toxicity tests with microalgae, both marine and freshwater species, and for different kind of pollutants.

Cell Division↗
PubMed2000

Capillary zone electrophoretic separation and determination of imidazolic antifungal drugs.

Capillary zone electrophoresis (CZE) was adapted to the simultaneous determination of a mixture of three imidazolic antifungal drugs. Separation was achieved by using a fused-silica capillary column with an acetic acid-Tris buffer at pH 5.18 and UV detection at 196 nm. Several electrophoretic parameters were investigated: pH and buffer concentration, applied voltage, temperature and injection conditions. The optimized CZE method was applied to the individual determination of ketoconazole, clotrimazole and econazole in pharmaceutical forms, after a previous single extraction step in methanol, with recoveries of 98.00, 99.96 and 99.58% respectively. The antifungal drugs can be determined at a concentration level lower than 1.0 x 10(-7) M.

Antifungal Agents↗
PubMed1999

A comparison of the relative sensitivity of structural and functional cellular responses in the alga chlamydomonas eugametos exposed to the herbicide paraquat.

The effect of the herbicide paraquat on the freshwater microalga Chlamydomonas eugametos was studied in function of different parameters such as growth, elemental composition, total lipids, and photosynthetic pigments content and others assayed by flow cytometry (cell viability, cell volume, and granularity). The study reveals that paraquat concentrations above 0.15 microM are toxic for the microalga C. eugametos, inducing an inhibition of all the physiological parameters analyzed and strong structural changes. However, lower concentrations cause alterations in certain cellular components that are especially sensitive to the toxic action of the herbicide; so total lipids and photosynthetic pigments content are affected by concentrations such low as 0.037 microM. Taking into account these results, these parameters are better indicators of the cellular state than data on biomass or growth rate.

Analysis of Variance↗
PubMed1999

Voltammetric and spectrophotometric techniques for the determination of the antihypertensive drug Prazosin in urine and formulations.

A sensitive method was developed to determine Prazosin using a nafion modified carbon paste electrode (NMCPE). Prazosin was accumulated at a potential of 750 mV in Britton-Robinson buffer (pH 6.0) and then a negative sweep was made obtaining a cathodic peak close to 0 V. Cyclic voltammetric studies indicated that the process was quasi-reversible, and fundamentally controlled by adsorption. To obtain a good sensitivity, the instrumental and accumulation variables were studied using differential pulse voltammetry (DPV). Adsorptive voltammetric peak currents showed a linear response for Prazosin concentrations in the range between 4.0 x 10(-11) and 4.0 x 10(-8) M with two different slopes, and a detection limit (LOD) of 3.1 x 10(-11)M was obtained. The variation coefficient (CV) for a 8.0 x 10(-10) M solution (n = 10) was 4.08%. A spectrophotometric study of Prazosin was also carried out and two absorption bands were obtained at 246 and 329 nm (pH 1.8). The band at 329 nm was pH-dependent and its height and position changed with the pH values, so this allowed the pK'a determination (7.14 +/- 0.20) using different methods. The detection limit reached by means of UV-spectrophotometry was 0.9 x 10(-7) M, and the variation coefficient for 1.5 x 10(-5) M Prazosin solutions was 1.14% (n = 10). Although the sensitivity of the UV-spectrophotometric method was lower than that obtained using adsorptive stripping-differential pulse voltammetry (AdS-DPV), it could be applied to the determination of Prazosin in Minipres tablets. The voltammetric method was used for the determination of the drug in human urine samples at trace levels with good recoveries.

Antihypertensive Agents↗
PubMed1999

Carboplatin plus cytarabine in the treatment of high-risk acute myeloblastic leukemia.

Thirty-one patients (20 male and 11 female; median age 51 years (16-79)) with high-risk acute myeloblastic leukemia (AML) (20 refractory AML and 11 secondary AML (s-AML) (four to myelodysplastic syndrome, five to chemo/radiotherapy, one to aplastic anemia and one blastic chronic myelogenous leukemia (B-CML)) were treated with CBDCA (300 mg/m2/day x 5 days in continuous i.v. infusion) plus intermediate-dose Ara-C (500 mg/m2/day x 3 days in rapid i.v. infusion). Nine patients (29%) achieved CR (five s-AML (three myelodysplastic syndromes, one CML and one ALL) and four refractory AML) and 11 patients had resistant disease. There were 11 early deaths (35%). Median disease-free survival of the nine responders was 4 months. The main toxicity was hematological, febrile episodes took place in nearly all the patients (96%). The CBDCA plus Ara-C regimen showed an evident antileukemic activity in high-risk leukemia. However, the lack of long-term disease-free survivors shows the need for innovative postremission strategies. The high initial response rate seen in AML secondary to myelodysplastic syndromes (MDS) warrants further investigation of CBDCA in combination regimens for MDS patients.

Adolescent↗
PubMed1998

[Assessment of 4 commercial immunoenzymatic assays for the serologic diagnosis of Helicobacter pylori infection].

BACKGROUND: The aim of this study was to evaluate four commercial tests for the serologic diagnosis of infection by Helicobacter pylori based on the detection of IgG class antibodies versus this microorganism. METHODS: Four commercial kits were analyzed based on the ELISA method in serum samples of 48 patients admitted for digestive endoscopy. The data of the serologic tests were compared with those provided by the culture, the histologic observation and the urease test of gastric biopsy specimens. The calculation of seroprevalence of anti-H. pylori antibodies in serum of 60 asymptomatic subjects was carried out. RESULTS: The seroprevalence of infection by H. pylori in an asymptomatic population of between 18 to 78 years of age was 58.33%. A sensitivity of 94.3% and a specificity of 88.9% were observed with the Pyloriset EIA-G test. The positive predictive value (PPV) was 92.2% and the negative predictive value (NPV) 91.5%. With the Chemifarma commercial kit the sensitivity was 78.8% and the specificity 100% with a PPV of 100% and NPV of 76.7%. Plate showed a sensitivity of 85.3% and a specificity of 87.5% with a PPV of 90% and a NPV of 80.76%. Milenia had a sensitivity of 80% and a specificity of 66.7% and a PPV of 77% and a NPV of 70.7%. CONCLUSIONS: The usefulness of the serologic tests for the diagnosis of Helicobacter pylori infection is herein confirmed with the test evaluated showing a high sensitivity and specificity as well as high predictive values.

Adolescent↗
PubMed1997

Cathodic stripping voltammetric determination of doxazosin in urine and pharmaceutical tablets using carbon paste electrodes.

Several voltammetric techniques were used to explore the reductive behaviour of the antihypertensive agent doxazosin on a bare carbon paste (CPE) and a Tenax-modified carbon paste electrode (TMCPE). The results indicate that the process is irreversible and fundamentally controlled by adsorption, which allows doxazosin to be accumulated at the electrode surface. The cathodic adsorptive stripping (AdS) response was evaluated with respect to pH, accumulation variables and instrumental parameters, using differential-pulse (DPV) and square-wave voltammetry (SWV) as redissolution techniques. In both cases, a voltammetric peak close to 0 V in Britton-Robinson buffer (pH 6.6) was obtained after a preconcentration step at 0.55 V for 3 min (2000 rpm) and a subsequent cathodic scan. When the TMCPE was used, the limits of detection were 4.35 x 10(-11) and 5.18 x 10(-11) M for AdS-DPV and AdS-SWV, respectively. The deposition time (3 min) was improved relative to that obtained by means of CPE (6 min). Under the optimum operational conditions, the doxazosin reduction peak showed a linear response in the range from 6 x 10(-11) to 1 x 10(-9) M by using AdS-DPV, with an RSD of 3.39% for 3 x 10(-8) M doxazosin solution (n = 10). A method was developed for the determination of doxazosin in human urine and formulations.

Adsorption↗
PubMed1997

[Clinical and epidemiologic study of meningococcal meningitis in the health region of Santiago de Compostela (1990-1997)].

BACKGROUND: The aim of this study was to determine the clinico-epidemiologic characteristics of meningitis caused by Neisseria meningitidis. METHODS: A retrospective study was performed of the bacterial meningitis with LCR positive cultures for Neisseria meningitidis from January 1990 to 31 March, 1997. To calculate the rate of incidence data from the 1990 population census were used corresponding to a population of 465,786 inhabitants per year attended in our hospital. RESULTS: A growth was observed in the strains of N. meningitidis in 61 LCR, representing 30% of all positive LCRs. Thirty-three strains belonged to serogroup B (54%) and 28 of serogroup C (46%). Ninety-one point nine percent of the cases were found in patients under the age of 20. The annual rates of incidence ranged from 2.3 cases/100,000 inhabitants in 1990 to 3.4 cases/100,000 inhabitants in 1996 with a slight decrease between these two dates. In patients under the age of 15 years, the rates of incidence ranged from 12.3/100,000 in 1990 to 13.4 per 100,000 inhabitants in 1996. In the remaining years the rates decreased with a minimum of 2.2 cases/100,000 inhabitants. The incidence for N. meningitis serogroup C ranged from 0 to 0.9 cases/100,000 inhabitants between 1990 and 1995. In 1996 the rate increased up to 2.6 cases/100,000 inhabitants. The rate of mortality was 6.6% and sequelae 8.7%. Since 1995 strains with decreased sensitivity to penicillin have been isolated, with percentages ranging from 20% to 56.25%. All strains remained sensitive to third generation cephalosporins and rifampicin. CONCLUSIONS: Neisseria meningitidis remains the most frequent etiologic agent of acute bacterial meningitis. The increase in serogroup C strains and the ever more frequent appearance of strains with decreased resistance to penicillin are confirmed, as is the persistence of high levels of endemia in our medium.

Adolescent↗