Changes in metal contents in shrimp cultured in NW Mexico (2000-2010).

This study shows the concentrations of Cd, Cu, Pb, and Zn in the muscle and hepatopancreas of Pacific white shrimps, Litopenaeus vannamei, cultured during 2010 in 26 commercial farms of the three main producer states of the Mexican NW, Sonora, Sinaloa, and Nayarit and compares the results to those obtained in 2000 using samples collected in16 farms of the same states. No significant changes were detected in Cd concentrations, but the 2010 Zn levels were significantly higher in all states in the hepatopancreas and in Sinaloa in the case of the muscle. Cu showed a tendency to higher hepatopancreas values in 2010, but differences were significant only in Sonora and for the global mean value. In contrast, Pb was one order of magnitude lower in both organs in 2010, possibly because of the almost 15 years since leaded gasoline was discontinued in Mexico.

Impact of fertilisation practices on soil respiration, as measured by the metabolic index of short-term nitrogen input behaviour.

The main objective of this study was the evaluation of the impact of different sources of organic waste (used as an N source) on soil quality (as measured by CO(2) release) and N transformation processes (available inorganic N forms) in a short-term field study of an almond tree plantation. Three compost types were used as organic fertilisers: EC compost constituted from organic agriculture farm (vegetables and manure), SC compost formed from sewage sludge and pruning waste composted, and XC compost comprised a mixture of composted sewage sludge plus slurry and manure from an intensive pig farm. The two compost doses were compared according to N content, and a high dose (H), corresponding to 210 kg N ha(-1), and a low dose (L), equivalent to 105 kg N ha(-1), were used. In addition, an N rate corresponding to 130 kg N ha(-1), which resulted from the supplementation of NPK mineral fertiliser with compost application at a low dose (mixed fertilisation), was compared in a parallel study. Generally, almost all organically treated soils demonstrated an improvement in the levels of C, N and P, compared to controls (unfertilised soils). In addition, the nitrate content increased, predominating over ammonium content, with the highest values in the soils with the low dose application of SC. Furthermore, soil respiration improved in organically treated soils, which showed different responses according to the organic-exogenous source of the incorporated matter. In contrast, a mineral supplement promoted a decrease in biological activity and resulted in lower CO(2) production in soils with XC and mineral fertiliser. Contrary to the organically treated soil, in soils with mix fertilisation the NH(4)(+)-N was the primary available form of nitrogen. However, the application of SC plus mineral fertiliser to soil caused a positive effect on CO(2) emissions compared to the control soil. Soil respiration behaviour was closely related to the form of inorganic N available in the soils due to the fertilisation practice type (organic or mixed), where both parameters seemed to depend on the mobilisations of cations (Na(+) and Ca(2+)) to the soil solution.

Infección por micobacterias no tuberculosas en pacientes con bronquiectasias no causadas por fibrosis quística / Non-tuberculous mycobacterial infection in patients with non-cystic fibrosis bronchiectasias

Objetivo. Conocer la prevalencia y características de la infección por micobacterias no tuberculosas en enfermos con bronquiectasias no relacionadas con la fibrosis quística. Pacientes y métodos. Estudio descriptivo retrospectivo de pacientes adultos con bronquiectasias no relacionadas con la fibrosis quística con un seguimiento de al menos dos años. Resultados. Se incluyeron 68 pacientes, 50 mujeres (73,5%), con una edad media de 63,31±16,2 años. La etiología más frecuente fue la enfermedad pulmonar obstructiva crónica (28 pacientes, 41,2%) con una afectación leve-moderada y colonización por Pseudomonas aeruginosa (P. aeruginosa) (70,6%). Siete pacientes (10,3%) presentaron infección por micobacterias no tuberculosas, tratándose de Mycobacterium avium complex en 6 ocasiones (7,35%). Cuatro (57,14%) pacientes recibieron tratamiento antimicrobiano específico. En los enfermos infectados fue menor la frecuencia de P. aeruginosa y el uso de corticoides inhalados. No hubo diferencias espirométricas significativas entre los pacientes infectados por micobacterias no tuberculosas y los no infectados. Conclusiones. Las bronquiectasias no relacionadas con la fibrosis quística podrían considerarse un factor de riesgo para la infección por micobacterias no tuberculosas(AU)

Aims. To know the characteristics and prevalence of non-tuberculous mycobacterial infection infection in patients with non-cystic fibrosis bronchiectasis. Patients and methods. A retrospective descriptive study of NCFB adult patients whose disease had been followed-up for at least two years was performed. Results. A total of 68 subjects were included, 50 females (73.5%), with mean age of 63.31± 16.2 years. The most frequent etiology of the non-cystic fibrosis bronchiectasis was COPD in 28 cases (41.2%) with a light-moderate pulmonary involvement and Pseudomonas aeruginosa (P. aeruginosa) colonization (70.6%). Seven patients (10.3%) had MNT infection, six of whom had Mycobacterium avium complex (7.35%). Four patients (57.14%) were treated. In the infected patients, P. aeruginosa and the use of inhaled steroids were observed with less frequency. There were no significant differences between the infected and non-infected patients in relation to spirometric values. Conclusions. The non-cystic fibrosis bronchiectasis could be considered a risk factor for non-tuberculous mycobacterial infection(AU)

[Non-tuberculous mycobacterial infection in patients with non-cystic fibrosis bronchiectasias]. / Infección por micobacterias no tuberculosas en pacientes con bronquiectasias no causadas por fibrosis quística.

AIMS: To know the characteristics and prevalence of non-tuberculous mycobacterial infection infection in patients with non-cystic fibrosis bronchiectasis. PATIENTS AND METHODS: A retrospective descriptive study of NCFB adult patients whose disease had been followed-up for at least two years was performed. RESULTS: A total of 68 subjects were included, 50 females (73.5%), with mean age of 63.31± 16.2 years. The most frequent etiology of the non-cystic fibrosis bronchiectasis was COPD in 28 cases (41.2%) with a light-moderate pulmonary involvement and Pseudomonas aeruginosa (P. aeruginosa) colonization (70.6%). Seven patients (10.3%) had MNT infection, six of whom had Mycobacterium avium complex (7.35%). Four patients (57.14%) were treated. In the infected patients, P. aeruginosa and the use of inhaled steroids were observed with less frequency. There were no significant differences between the infected and non-infected patients in relation to spirometric values. CONCLUSIONS: The non-cystic fibrosis bronchiectasis could be considered a risk factor for non-tuberculous mycobacterial infection.

Metal contents of four commercial fish species of NW Mexico.

The metal contents in tissues of fish species: M. cephalus, Diapterus sp., Scomberomorus sierra and Oreochromis aureus, were determined in order to evaluate if their consumption might become a health risk. The liver and gills of M. cephalus and Diapterus sp. had the highest values of Cu, Fe and Pb. In the muscle, there were no interspecific differences in the Cd, Cu and Pb contents (0.27-0.32, 0.96-1.30 and 2.12-2.80 microg/g dw, respectively). Cd and Pb may be of concern, since their mean contents in the edible muscle of the four species are higher than the limits of the European Community.

Cadmium, copper, lead and zinc contents of the mangrove oyster, Crassostrea corteziensis, of seven coastal lagoons of NW Mexico.

The ranges of concentrations of Cd, Cu, Pb and Zn of the soft tissues of C. corteziensis collected in seven coastal lagoons of NW Mexico were 1.55-7.45, 17.50-166.36, 4.13-9.49 and 245.34-2,304.12 microg/g (dry weight), respectively. Their distributions were not consistent and there were no seasonal trends, indicating different point sources of the metals in each lagoon. The mean Cd and Pb concentrations were 5.34 and 6.30 microg/g (dry weight), which are higher than the values indicative of polluted areas. Our data indicate that only the levels of Cd are a possible health risk in six of these lagoons, and only in the case of regular local consumers. In one, Cu and Zn reach levels of concern.

Metal content of the gulf of California blue shrimp Litopenaeus stylirostris (Stimpson).

The blue shrimp Litopenaeus stylirostris is the main target species of the Gulf of California shrimping fleet, and its heavy metal content might be of concern for human health because of the increasing contamination of the Gulf. The Cd content of shrimp caught by commercial trawlers ranged from 0.38 to 1.05 microg/g and the mean value was significantly lower in the northern fishing grounds. Pb ranged from 3.19 to 9.59 microg/g and was significantly higher in the northern area. There were no significant geographic difference in the case of Cu and Zn (respective means = 25.4 and 57.8 microg/g). The mean values of all metals show that none is of particular concern for human health.

Propafenone modulates potassium channel activities of vascular smooth muscle from rat portal veins.

We have studied the effects of the class Ic antiarrhythmic propafenone on K+ currents in freshly isolated smooth muscle cells from rat portal veins and on the spontaneous contractions in whole tissues. Under Ca2+-free conditions, when cells were clamped at -80 mV (whole-cell configuration) depolarizing steps from -80 to +50 mV induced a family of K+ currents (I(Ktotal)) that mainly comprised the delayed rectifier current [I(K(V))], whereas when held at -10 mV only small-amplitude, noninactivating, currents (I(NI)) were recorded. Propafenone (10 microM) markedly inhibited I(Ktotal), but at potentials positive to +30 mV it also induced a noisy outwardly rectifying current [I(BK(Ca))] that was abolished by iberiotoxin (0.1 microM). Inhibition of I(Ktotal) by propafenone was concentration-dependent (EC50 = 0.059 +/- 0.009 microM). Propafenone also inhibited the transient outward current [I(K(A))] and ATP-sensitive potassium current [I(K(ATP))] induced by levcromakalim (10 microM). Inhibition of I(K(V)), I(K(A)), and I(K(ATP)) by propafenone was voltage-independent. In Ca(2+)-containing conditions propafenone inhibited I(K(V)) and I(BK(Ca)) and immediately abolished spontaneous outward transient K+ currents. In whole veins, propafenone behaved as the K(V) inhibitor 4-aminopyridine, increasing the amplitude and duration of spontaneous contractions. Propafenone also inhibited the inhibitory effects of the K(ATP) channel opener levcromakalim on spontaneous contractions. These results indicate that in vascular smooth muscle cells, propafenone inhibits K(V), K(A), BK(Ca), and K(ATP) channels. These actions correlated with its effects on mechanical activity in whole portal veins.

Mechanisms involved in SNP-induced relaxation and [Ca+]i reduction in piglet pulmonary and systemic arteries.

1. We have compared the mechanisms involved in sodium nitroprusside (SNP)-induced relaxation and [Ca2+]i reduction in isolated piglet pulmonary (PA) and mesenteric (MA) arteries. 2. SNP (10(-8) M-3x10(-5) M) evoked a concentration-dependent relaxation of PA and MA (pD2=6.66+/-0.06 and 6.74+/-0.14, respectively) stimulated by noradrenaline, which was markedly reduced by the guanylate cyclase inhibitor ODQ. In fura 2-incubated PA and MA, SNP produced a parallel reduction in contractile force and in [Ca2+]i, expressed as the ratio of emitted fluorescence at 340 and 380 nm (F340/F380). 3. The inhibition of the Na+/K+-ATPase after the incubation in a K+-free medium or the exposure to ouabain (10(-6) M) inhibited SNP-induced relaxation in MA but not in PA. SNP-induced relaxation was not attenuated by 80 mM KCl plus nifedipine (10(-6) M) but was inhibited by thapsigargin (2x10(-6) M; pD2=5.69+/-0.19 and 5.89+/-0.19 for PA and MA, respectively). 4. Pretreatment of PA with thapsigargin and MA with thapsigargin plus ouabain induced a stronger inhibition on the reduction in [Ca2+]i than on the relaxation induced by SNP, indicating the existence of Ca2+-independent mechanisms. 5. The activation of the Na+/K+-ATPase by the addition of KCl after the incubation in a K+-free medium similarly reduced [Ca2+]i in PA and MA, whereas it relaxed with much less efficacy PA than MA. 6. We conclude that SNP reduces [Ca2+]i and causes relaxation through the activation of SERCA in PA and SERCA and Na+/K+-ATPase in MA. However, Ca2+-independent mechanisms also contribute to SNP-induced effects.

[The activity of eight fluoroquinolones versus biolayers of Escherichia coli and Pseudomonas aeruginosa in siliconized latex urinary catheters]. / Actividad de ocho fluoroquinolonas frente a biocapas de Escherichia coli y Pseudomonas aeruginosa sobre sondas urinarias de látex siliconizado.

OBJECTIVE: To evaluate the in vitro activity of eight fluoroquinolones against Escherichia coli and Pseudomonas aeruginosa biofilms on siliconized latex urinary catheters. MATERIAL AND METHODS: The MICs and MBCs of norfloxacin, ciprofloxacin, ofloxacin, levofloxacin, clinafloxacin, sparfloxacin, trovafloxacin, and moxifloxacin for two strains of E. coli (CBR-3 and CBR-4) and two strains of P. aeruginosa (HUS-3 and PBR-2) were determined according to the NCCLS guidelines. The susceptibility of bacteria attached to siliconized latex catheters to fluoroquinolones was also evaluated. Catheter segments containing 6 or 24 hours old biofilms were used as inocula for the studies of antimicrobial activity against bacterial biofilms. RESULTS: MICs of ciprofloxacin for planktonic and attached bacteria were equal. MICs values for the others fluoroquinolones increased two or more times when bacterial biofilms were used as inocula, except for ofloxacin and E. coli CBR-4, trovafloxacin and E. coli CBR-3, and levofloxacin and trovafloxacin and P. aeruginosa PBR-4; in these cases the MIC values for planktonic and attached bacteria were similar. When bacteria attached to siliconized latex were used as inocula, MBCs values increased 8-> 4,096-fold for all the fluoroquinolones evaluated. CONCLUSIONS: E. coli and P. aeruginosa biofilms on siliconized latex were more resistant to the bactericidal activity of fluoroquinolones than planktonic bacteria.

Effect of plastic catheter material on bacterial adherence and viability.

The kinetics of adherence of single isolates of Staphylococcus aureus, S. epidermidis, Pseudomonas aeruginosa and Escherichia coli to catheters made of polyvinyl chloride (PVC), Teflon, siliconised latex, polyurethane and Vialon was evaluated by a radiometric assay. Radiolabelled bacteria (10(8) cfu/ml) were incubated in vials containing 1-cm lengths of catheter for up to 3 days. The peak of maximal adherence to each biomaterial was reached after 24 h for P. aeruginosa and after 72 h for the other strains. Bacterial adherence to PVC and siliconised latex was significantly higher (2-6 times; p less than 0.05) than to the other biomaterials for all the strains. The lowest values of adherence were observed with polyurethane and Vialon for the staphylococci but with Teflon for E. coli and P. aeruginosa. Bacterial viability and growth was evaluated in eluates obtained from incubation of segments of each catheter in buffer for 24 h. None of the eluates affected the viability of the staphylococci. However, all of them, significantly increased the growth of E. coli and P. aeruginosa with the exception of the eluate from siliconised latex, in which the inoculum count was reduced to an undetectable level for E. coli. We conclude that bacterial adherence to catheters may depend in part on the nature of the biomaterial and that certain substances eluted from the catheters may affect the viability and growth of different micro-organisms.

Effect of a siliconized latex urinary catheter on bacterial adherence and human neutrophil activity.

The effect of a siliconized latex urinary catheter on the in vitro adherence and growth of Pseudomonas aeruginosa and Escherichia coli and on the activity of human polymorphonuclear leukocytes (PMNs) was assessed. The adherence of P. aeruginosa to latex catheters was significantly greater than that of E. coli, being 30 times higher at 6 hr of incubation. The survival of E. coli (10(8) CFU/ml) in phosphate-buffered saline (PBS) containing segments of siliconized latex catheters was lower than in the controls. This effect seems to be due to a toxic effect produced by substances eluted into the medium from the catheters, as the viability of E. coli (10(3) CFU/ml) in eluates obtained from the incubation of catheters in PBS (24 hr; 37 degrees C) was significantly lower than in the controls. These phenomena were not observed with P. aeruginosa. The incubation of human PMNs with either catheter segments or eluates did not affect the uptake of opsonized E. coli but significantly decreased the production of superoxide radicals by these phagocytes. It is concluded that the adherence of P. aeruginosa to these catheters is higher than that of E. coli and that the latex urinary catheter used herein elutes substances that are in vitro toxic for E. coli and the oxygen-dependent bactericidal mechanisms of human PMNs.

Effect of ampicillin/sulbactam on human polymorphonuclear leukocyte function.

The effect of ampicillin and sulbactam on the interaction in vitro of human polymorphonuclear leukocytes (PMN) with Staphylococcus aureus was examined. The exposure of a non-penicillinase-producing S. aureus strain to one fourth the MIC of ampicillin but not of sulbactam significantly increased the uptake of bacteria by human PMN. This effect was also observed when bacteria were exposed to the MIC0.25 of different combinations of ampicillin and sulbactam (2/1, 1/1, 1/4, 1/8 and 1/32). These effects were not observed when a penicillinase-producing strain was used. The production of superoxide and hydrogen peroxide radicals by human PMN was not affected by the presence of these antimicrobials. Ampicillin and sulbactam, neither alone nor in combination, showed intracellular activity against S. aureus within human PMN.