Showing papers by "Autonomous University of Barcelona published in 1990"

Plant water relations as affected by heavy metal stress: A review

Abstract: High metal availability, arising from mining and industrial activities, disposal of sewage sludge or soil acidification, is an increasing problem in agriculture and forestry. Metal toxicity causes multiple direct and indirect effects in plants which concern practically all physiological functions. In this review we consider the effects of excess heavy metals and aluminium on those functions which will alter plant water relations. After a brief comment on the metal effects in cell walls and plasmalemma, and their consequences for cell expansion growth, the influences of high metal availability on the factors which regulate water entry and water exit in plants are considered. Emphasis is placed on the importance of distinguishing between low water availability in mine and serpentine soils and toxicity effects in plants which may impair the regulation of a plant's water household. Examples on water relations of both plants grown on metalliferous soil and hydroponics are discussed. The effects of met...

Aleph: a detector for electron-positron annihilations at Lep

Abstract: Process-centred Software Engineering Environments (PSEE) are the most recent generation of environments supporting software development activities. Most of PSEE are based on mechanisms promoting enforcement and automation of process activities. In this kind of mechanisms the process models are prescribed in a detailed and complete way. But the experience shows that supporting processes is more concerned with the flexibility of guidance offered during the process performance than with enforcement of a collection of predefined process models. In this paper, we present a solution to support strategic processes in a PSEE by providing a flexible guidance during process enactment.

Dietary fish oil reduces progression of chronic inflammatory lesions in a rat model of granulomatous colitis.

Abstract: Eicosanoids are modulators of defensive and inflammatory processes in the gut mucosa, and may be involved in the pathogenesis of chronic inflammatory lesions of the bowel. As omega-3 fatty acids compete with the omega-6 as precursors of eicosanoid synthesis, we compared the effects of dietary supplementation with either sunflower (source of omega-6) or cod liver (source of omega-3) oil on the development of chronic granulomatous lesions in the rat colon. After four weeks on the supplemented diets, plasma omega-6 fatty acid content was significantly higher in the sunflower group, while omega-3 fatty acids predominated in the cod liver group. Inflammatory colitis was then induced by intracolonic administration of trinitrobenzene sulphonic acid. Luminal eicosanoid release, as measured by radioimmunoassay of intracolonic dialysis fluid, increased significantly after the challenge in both groups. Generation of prostaglandin E2 (PGE2) and leucotriene B4 (LTB4) peaked by day 3 and thereafter declined; thromboxane B2 (TXB2), instead, continued to increase from day 3 to 20 in sunflower fed rats, whereas this change was blunted in cod liver animals. The rats were killed 20, 30, or 50 days after the induction of colitis, and the colonic lesions were scored macroscopically (adhesions to surrounding tissues, strictures, ulcerations, and wall thickness) and histologically (ulceration, inflammation, depth of the lesions, and fibrosis). In cod liver animals, the damage score was markedly reduced by day 30, and inflammation and ulceration were almost absent by day 50. In conclusion, a fish oil diet prevents the increase in thromboxane in the chronic state of inflammation and shortens the course of the colonic disease by diminishing both the severity of the lesions and their progression to chronicity.

Anticipative calculus for the Poisson process based on the Fock space

Abstract: © Springer-Verlag, Berlin Heidelberg New York, 1990, tous droits réservés. L’accès aux archives du séminaire de probabilités (Strasbourg) (http://portail. mathdoc.fr/SemProba/) implique l’accord avec les conditions générales d’utilisation (http://www.numdam.org/conditions). Toute utilisation commerciale ou impression systématique est constitutive d’une infraction pénale. Toute copie ou impression de ce fichier doit contenir la présente mention de copyright.

Strategy-proof voting schemes with continuous preferences

Abstract: We prove that all nondictatorial voting schemes whose range has more than two alternatives will be manipulable, when their domain is restricted to the set of all continuous preferences over alternatives. Our result neither implies nor is implied by the original Gibbard-Satterthwaite theorem, except if the number of alternatives is finite, when they coincide. A new, direct line of reasoning is used in the proof. It is presented in an introductory section, which may be useful in classroom situations.

Sexual transmission of hepatitis C virus and its relation with hepatitis B virus and HIV.

Abstract: OBJECTIVE--To determine the extent of transmission of hepatitis C virus in sexual partners of intravenous drug misusers and to examine the relation between the prevalences of HIV, hepatitis B virus, and hepatitis C virus infections in homosexual men and intravenous drug misusers and their sexual partners. DESIGN--Serum samples collected between 1984 and 1988 were tested for hepatitis B virus markers and antibodies against hepatitis C virus by enzyme linked immunosorbent assay (ELISA) and for HIV antibody by enzyme immune analysis and western blotting. SETTING--Large referral university hospital with an external AIDS clinic in the metropolitan area of Barcelona, Spain. SUBJECTS--243 Intravenous drug misusers, 143 of their regular heterosexual partners, and 105 homosexual men. MAIN OUTCOME MEASURES--Prevalences of hepatitis C virus, hepatitis B virus, and HIV infections. RESULTS--In all, 178 of the 243 (73%) intravenous drug misusers, 16 out of 143 (11%) of their partners, and 17 of the 105 (16%) homosexual men had antibodies against hepatitis C virus. The presence of hepatitis C virus infection was unrelated to sex, age, the presence of HIV or hepatitis B virus infections, or the Centers for Disease Control stage of HIV. In sexual partners of intravenous drug misusers there were strong correlations between the presence of hepatitis C virus infection and that of HIV (p = 0.001) and hepatitis B virus (p = 0.013) infections. CONCLUSIONS--Intravenous drug misusers have a high risk of acquiring hepatitis C virus, hepatitis B virus, and HIV infections, but the presence of hepatitis C virus infection seems to be unrelated to the presence of the other two viruses. Homosexual men have a high prevalence of HIV and hepatitis B virus infections with a low prevalence of hepatitis C virus infection, the presence of which is not related to that of the other two infections. Conversely, heterosexual partners of intravenous drug misusers have low prevalences of the three virus infections, but the presence of hepatitis C virus infection correlates significantly with the presence of HIV and hepatitis B infections. The rate of sexual transmission of hepatitis C virus seems to be low, even in partners of people known to be seropositive for this virus.

Induction of SOS genes in Escherichia coli and mutagenesis in Salmonella typhimurium by fluoroquinolones.

Abstract: The induction of several SOS genes of Escherichia coli by fluoroquinolones has been studied. Three different SOS gene fusions (recA::lacZ, umuC::lacZ and sulA::lacZ) have been introduced into the E.coli MC1061 strain to study the induction of these SOS genes in the same genetic background. Data on the basal level of expression of these fusions, as well as their induction by mitomycin C and N-methyl-N'-nitro-N-nitrosoguanidine are presented. Using these strains, we have found that, like nalidixic acid, ofloxacin, enoxacin and ciprofloxacin are strong inducers of the SOS genes tested, umuC gene expression being the highest. Furthermore, fluoroquinolones produced a significant increase in the reversion of the base substitution hisG428 mutation in the TA102 Salmonella tester strain, while no effect was found in strains TA98, TA100, TA1537 and TA1535. These data indicate that the error-prone repair pathway can participate in mutagenesis induced by fluoroquinolones and also that the damage produced by these chemicals may be similar to that produced by nalidixic acid.

Gentamicin volume of distribution in critically ill septic patients.

Abstract: Gentamicin intrapatient pharmacokinetics variations were studied in 40 critically ill medical patients, suffering gram-negative sepsis. These patients were studied in two phases throughout gentamicin treatment: firstly, on the second day of treatment, when aggressive fluid therapy was required, and secondly, five days later, when patients had achieved a more stable clinical condition. Pharmacokinetic parameters were determined using least squares linear regression analysis assuming a one-compartment model using the Sawchuk-Zaske method. The apparent volume of distribution (Vd) in the first phase of the study was 0.43 +/- 0.12 L/kg, while on the seventh day of treatment it was 0.29 +/- 0.17 L/kg (p less than 0.001). Statistically significant differences were also observed for peak serum concentration (p less than 0.001), total dosage recommended (p less than 0.001) and half-life (p less than 0.05), whilst differences were not found for trough levels. From the analysis of the results obtained, we recommend increasing the initial dosage and monitoring plasma levels within the first days of therapy in critically ill patients treated with gentamicin, since important variations in aminoglycoside Vd related to disease, fluid balance and renal function, commonly occur in these patients.

Endotracheal tube cuff pressure assessment: pitfalls of finger estimation and need for objective measurement.

Abstract: Estimation of endotracheal (ET) cuff pressure by finger palpation is one of the methods currently used in the clinical setting. We compared the accuracy of this method with instrumental intracuff pressure measurement in tracheal model tests by 20 members of our ICU team. Four different ET tubes at three different pressure levels were examined. Accuracy for the estimated method by finger palpation was 69% for high pressures, 58% for normal pressures, and 73% for low pressures. We observed differences in terms of sensitivity, specificity, and positive predictive power between different tubes reflecting differences in tube characteristics and interobserver variability. We conclude that precise intracuff pressure measurement is mandatory to prevent complications of over- or underinflation.

Severe deficiency of docosahexaenoic acid in peroxisomal disorders: a defect of delta 4 desaturation?

Abstract: In confirmation of previous findings, patients with Zellweger's syndrome had extremely low levels of docosahexaenoic acid (22:6 omega 3) in the brain, liver, and kidneys. The other product of delta 4 desaturation, 22:5 omega 6, was also very significantly decreased, as were the ratios 22:6 omega 3/22:5 omega 3 and 22:5 omega 6/22:4 omega 6, especially in the brain and liver of the Zellweger patients. The infant with pseudo-Zellweger's syndrome also had very low levels of 22:6 omega 3 and of the ratio 22:6 omega 3/22:5 omega 3 in all tissues, especially in the brain, where the index 22:5 omega 6/22:4 omega 6 was also very significantly reduced. The ratio 22:6 omega 3/22:4 omega 6 was markedly decreased in all tissues, in Zellweger's as well as in pseudo-Zellweger's syndrome. The findings reported here strongly reinforce the hypothesis of a new enzymatic defect in peroxisomal disorders involving the desaturation of long polyunsaturated fatty acids, especially of the omega 3 family.

Risk factors for Staphylococcus aureus nosocomial pneumonia in critically ill patients.

Abstract: Staphylococcus aureus nosocomial pneumonia has become an important infection not only because of an apparently increasing incidence but also because of its high mortality rate. A total of 50 episodes of nosocomial pneumonia in critically ill patients in which etiologic diagnosis was well established were prospectively followed in a medical-surgical intensive care unit (ICU). S. aureus was isolated in a total of 13 episodes. In the univariate analysis the variables significantly associated with S. aureus nosocomial pneumonia were below 25 yr of age, coma, nonuse of corticosteroids, and antecedent trauma. A step-forward logistic regression analysis defined only coma as significantly influencing the risk of developing S. aureus nosocomial pneumonia. We suggest that antimicrobial drugs active against S. aureus must be included in the initial empirical antimicrobial regimen for treating nosocomial pneumonia in patients with coma. The identification of factors influencing the etiology and the possibility of ear...

Is experimental catalepsy properly measured

Abstract: Following logarithmic transformation (ln) of total duration of haloperidol-induced catalepsy in the rat, measured by means of the bar test, a normalization of the results is achieved. With the help of this transformation we have been able to study what are probably the most important variables involved in the measuring of experimental catalepsy and to establish some criteria for a better use of such measures: 1) repeated measures of catalepsy have to be taken in order to avoid the stress-induced inhibition of catalepsy caused by the new experimental situation, 2) the dose of neuroleptic used has to be sufficiently low to permit the measurement of total or real duration of catalepsy between two determinations, and 3) the dose of neuroleptic has to be sufficiently high to prevent the development of a learned “pseudocatalepsy.”

Recurrent pericarditis. Relief with colchicine.

Abstract: Recurrence is one of the major complications of pericarditis. Treatment of recurrence is often difficult, and immunosuppressive drugs or surgery may be necessary. We conducted an open-label prospective study of nine patients (seven men and two women; age, 18-64 years; mean age, 41.7 +/- 13.7 years). Patients were treated with colchicine (1 mg/day) to prevent recurrences. All patients had suffered at least three relapses despite treatment with acetylsalicylic acid, indomethacin, prednisone, or a combination. Pericarditis was classified as idiopathic in five patients, postpericardiotomy in two, post-myocardial infarction in one, and associated with disseminated lupus erythematosus in one. For statistical analysis, we conducted a paired comparison design (Student's t test). All patients treated with colchicine responded favorably to therapy. Prednisone was discontinued in all patients after 2-6 weeks (mean, 26.33 +/- 10.9 days), and colchicine alone was continued. After a mean follow-up of 24.3 months (minimum, 10 months; maximum, 54 months), no recurrences were observed in any patient; there was a significant difference between the symptom-free periods before and after treatment with colchicine (p less than 0.002). Our study suggests that colchicine may be useful in avoiding recurrence of pericarditis, although these results need to be confirmed in a larger, double-blind study.

Biological effects of androgens and identification of specific dihydrotestosterone-binding sites in cultured human fetal epiphyseal chondrocytes.

Abstract: The biological effects of dihydrotestosterone (DHT) and testosterone (T) on cultured human fetal epiphyseal chondrocytes were assessed by studying the ability of these androgens to promote DNA synthesis. DNA synthesis was evaluated by measuring [3H]thymidine incorporation into DNA. After 48-h incubation in Ham's F-12 serum-free medium, chrondrocytes were incubated with or without DHT (10(-11)-10(-8) M) or T (10(-11)-10(-8) M) in MCDB-104 serum-free medium for a further 48 h, with the addition of [3H]thymidine (5 microCi/mL) for the last 24 h. In chondrocytes from five male fetuses (12-40 weeks' gestation) DHT and T significantly stimulated DNA synthesis. The maximum stimulatory effect was obtained for DHT at 10(-10) M (P less than 0.01) and for T at 10(-6) M (P less than 0.02). In chondrocytes from four female fetuses the stimulatory effect was significant only for DHT and was maximum at 10(-10) M (P less than 0.02), whereas no effect was observed for T. Cultured chondrocytes from both male and female fetuses show the presence of proteins with high affinity and limited binding capacity (Bmax) for DHT (male fetuses: Bmax, 4.9 +/- 1.9 x 10(-15) M/mg protein; Kd, 0.43 +/- 0.24 x 10(-9) M; female fetuses: Bmax, 4.8 +/- 1.6 x 10(-15) M/mg protein; Kd, 0.63 +/- 0.19 x 10(-9) M) with no significant differences between sexes. In conclusion, our results show that androgens elicit a biological response in cultured human fetal epiphyseal chondrocytes and that DHT-binding sites are present in these cells. DHT, rather than T, seems to be the active androgen. A sex difference in the degree of androgen action is also documented.

Distribution of insertion sequence IS200 in Salmonella and Shigella

Abstract: Summary: Two DNA probes for the detection of insertion sequence IS200 by either Southern blotting or colony hybridization were constructed. One of the probes is a 300 bp EcoRI-HindIII fragment of IS200 cloned onto pBluescript KS(+); the other is a tail-to-tail dimer of the same fragment cloned onto pUC19. A survey of the presence of IS200 among enteric bacteria revealed that more than 90% of the pathogenic or food-poisoning isolates of Salmonella spp. examined contained one or more copies of insertion sequence IS200, with the exception of the subgenus I serovar S. agona in which IS200 is not found. Although insertion sequence IS200 was first considered a Salmonella-specific element, it also exists in many isolates of Shigella sonnei and Shigella flexneri, but not in Shigella dysenteria.

Über das Relativitätsprinzip und die aus demselben gezogenen Folgerungen

Abstract: Die Newtonscken Bewegungsgleichungen behalten ihre Form, wenn man auf ein neues, relativ zu dem ursprunglich benutzten in gleichformiger Translationsbewegung begriffenes Koordinatensystem transformiert nach den Gleichungen $$\begin{gathered} x' = x - vt \hfill \\ y' = y \hfill \\ z' = z \hfill \\ \end{gathered}$$

Reaction scheme of lipase production by Candida rugosa growing on olive oil

Abstract: In a study of lipase production byCandida rugosa growing on olive oil, the relationship between the consumption of substrate and lipase production is presented. Two stages could be observed in the consumption of the olive oil: a first one, related with the glycerol depletion without lipase production, and a second one, associated with the fatty acids consumption when the enzyme appears in the medium.

Primary Meningococcal Conjunctivitis: report of 21 Patients and Review

Abstract: Neisseria meningitidis is an uncommon cause of acute bacterial conjunctivitis. Twenty-one cases of primary meningococcal conjunctivitis (PMC) are reported herein and 63 cases published in the literature since 1899 are reviewed. In the 84 cases of PMC available for analysis, the male-to-female ratio was 1.76:1; nine of the patients were neonates, 55 were children, and 20 were adults. Conjunctivitis was unilateral in 66.3% of the patients. Gram stain of conjunctival exudate disclosed gram-negative diplococci in all cases in which it was done. Culture of the conjunctival exudate yielded N. meningitidis in all cases, and 44% of the isolated meningococci belonged to serogroup B. Ocular complications, which occurred in 15.5% of the patients, most frequently were corneal ulcers. Systemic meningococcal disease developed in 17.8% of the patients; the overall mortality was 13.3% for patients with PMC complicated by systemic disease. Development of systemic disease was significantly more frequent in patients receiving only topical therapy than in those treated with systemic therapy (31.71% vs. 2.38%; P = .001). Gram-negative diplococci observed in conjunctival exudate are an indication for systemic antibiotic therapy because of the risk of systemic complications associated with the use of topical therapy alone. When properly treated, patients with PMC have a favorable prognosis.

Preliminary estimates of cumulative caesium and plutonium deposition in the Irish terrestrial environment

Abstract: A number of soil and peat cores, sampled throughout Ireland from November 1987 to March 1988, have been analyzed for fallout caesium and plutonium. Specifically,134Cs and137Cs levels were measured by high resolution gamma spectrometry while238Pu and239,240Pu were determined after chemical extraction by alpha spectrometry. The inventories of these nuclides at the locations sampled have been calculated from the resulting profiles and, by extrapolation, preliminary estimates made of the cumulative deposition throughout Ireland. The relative contribution from weapons testing in the atmosphere and the Chernobyl accident to the total caesium inventory have been determined by the134Cs/137Cs isotopic ratio. As expected, no plutonium of Chernobyl origin was detected in surface layers. The cumulative238Pu/239,240Pu ratio measured in Irish soils was found to be consistant with mid-latitude ratios reported by others.

Mechanism of formaldehyde biodegradation by Pseudomonas putida.

Abstract: Formaldehyde biodegradation by a strain of Pseudomonas putida has been studied. The results indicate that this biodegradation is initiated by a dismutation reaction, yielding as products formic acid and methanol. The degradation of methanol and formic acid begins after exhaustion of formaldehyde in the medium, and presents a diauxic pattern: first formic acid is consumed followed by methanol. Moreover, cell viability, which is affected by the amount of added formaldehyde, has been determined.