Symmetry Breaking in Escaping Ants

The phenomenon of herding is a very general feature of the collective behavior of many species in panic conditions, including humans. It has been predicted theoretically that panic-induced herding in individuals confined to a room can produce a nonsymmetrical use of two identical exit doors. Here we demonstrate the existence of that phenomenon in experiments, using ants as a model of pedestrians. We show that ants confined to a cell with two symmetrically located exits use both exits in approximately equal proportions to abandon it in normal conditions but prefer one of the exits if panic is created by adding a repellent fluid. In addition, we are able to reproduce the observed escape dynamics in detail using a modification of a previous theoretical model that includes herding associated with a panic parameter as a central ingredient. Our experimental results, combined with theoretical models, suggest that some features of the collective behavior of humans and ants can be quite similar when escaping under panic.

Reductive Cleavage of Tetrahydrofuryl Sulfur-Substituted Oxiranes: Application to the Formal Synthesis of Kumausyne and Kumausallene

[reactions: see text] Readily available sulfinyl and sulfonyl tetrahydrofuran methanol derivatives have been transformed efficiently into a variety of substituted tetrahydrofuryl alcohols by treatment with (PhSe)2 in the presence of an excess of NaBH4. Alternatively, oxirane cleavage with MgI2 produces the related ketones, amenable to stereocontrolled reduction. This reductive cleavage methodology has been applied to short formal syntheses of trans-Kumausyne and Kumausallene.

Pho d 2, a major allergen from date palm pollen, is a profilin: cloning, sequencing, and immunoglobulin E cross-reactivity with other profilins

BACKGROUND

Up to now, some date palm pollen (DPP) allergens have been described but very few data are available about their molecular nature. The aim of this study was to identify and characterize Pho d 2, a major allergen from this pollen.

METHODS

Sera from 25 patients allergic to DPP were analysed by immunoblotting. Purification of DPP profilin was performed by poly-l-proline affinity chromatography. Profilin-encoding cDNA from DPP was cloned by using a RT-PCR strategy and recombinant allergen was expressed as a non-fusion protein in Escherichia coli. Natural and recombinant Pho d 2 were investigated by means of enzyme allergosorbent test to compare the immunologic properties of both allergens and to analyse cross-reactivity with other profilins.

RESULTS

A 14.4 kDa protein was identified as a major allergen in DPP extract. Purification, cloning, heterologous expression, and inhibition experiments identified it as profilin (Pho d 2). Pho d 2 comprises 131 amino acids and has high sequence identity with other allergenic food and pollen profilins. The prevalence of specific IgE antibody reactivity to natural Pho d 2 by ELISA was 56% and 64% by skin prick test (SPT). Pho d 2 is an important allergen as it is responsible for more than 70% of the IgE reactivity to the pollen extract. IgE directed against Pho d 2 showed a strong cross-reactivity with other profilins such as those from olive tree and grass pollens.

CONCLUSION

Pho d 2, a 14.4 kDa protein identified as profilin, is a major and relevant allergen in DPP, as confirmed by SPT and thereby may elicit clinical symptoms in sensitized patients.

Benefits from marker-assisted selection under an additive polygenic genetic model1

This study investigated, through stochastic computer simulation, the extra gains expected from marker-assisted selection (MAS) in an infinitesimal model with linkage. The trait under selection was assumed to be controlled by 2,000 loci of additive small effect and evenly distributed in c chromosomes of one Morgan each (and c = 5, 10, 20, or 30). This approach differs from previous studies on the benefits of MAS that have considered mixed inheritance models. Marker information was used together with pedigree information to compute the relationship matrix used in BLUP genetic evaluations. The MAS schemes were compared with schemes where genetic evaluations were performed using standard BLUP (i.e., the relationship matrix is obtained using pedigree information only). When the number of markers was large enough (approximately one marker every 10 cM), there were increases in the accuracy of selection with MAS, and this led to extra gains compared with standard BLUP for all genome sizes considered. The benefit from MAS increased over generations. At the last generation of selection (Generation 10), the response from MAS was 11, 9, 7, and 5% greater than with standard BLUP for genomes with 5, 10, 20, and 30 chromosomes, respectively. Thus, although small, gains from MAS were nonetheless detectable for genome sizes typical of livestock populations.

Genetic differentiation and estimation of effective population size and migration rates in two sympatric ecotypes of the marine snail Littorina saxatilis

On exposed rocky shores in Galicia (northwest Spain), a striking polymorphism exists between two ecotypes (RB and SU) of Littorina saxatilis that occupy different levels of the intertidal zone and exhibit an incomplete reproductive isolation. The setting has been suggested to represent ongoing sympatric speciation by ecological adaptation of the two ecotypes to their respective habitats. In this article we address whether or not the ecotypes have developed their own population structures in response to the rigors of their corresponding environments and life histories. We analyzed four to five allozymic loci from three surveys of the same sites, spanning a 14-year period. An experimental design including three localities with two transects per locality and three shore levels allowed studying temporal and spatial population structure and estimation of effective population sizes (N(e)), neighborhood sizes (N(n)), and migration rates (m). Genetic differentiation was significantly lower in RB populations (theta(ST) = 0.067) than in SU ones (theta(ST) = 0.124). Mean estimates of N(e), N(n), and m did not differ significantly between ecotypes, but local ecotype differences in migration between the two closest localities (larger migration rates in RB than in SU populations) could explain the pattern in population differentiation.

The influence of hepatitis B and hepatitis C virus infection in the recipient on late renal allograft failure

BACKGROUND

Chronic liver disease is one of the most important complications after renal transplantation. Hepatitis B and mainly hepatitis C are the more frequent causes of liver disease. Although there are controversial results, in some series, hepatitis B and hepatitis C are associated with lower graft and patient survival.

PATIENTS AND METHODS

A total of 3365 adult patients who received a renal transplant in 1990 (N = 824), 1994 (N = 1075) and 1998 (N = 1466) with a functioning graft after the first year were included. Fifty-one (2.1%) with positive HbsAg were diagnosed with hepatitis B at transplantation; 488 (16.9%) presented positive anti-hepatitis C antibodies and were diagnosed with hepatitis C virus (HCV) infection and 25 patients (0.8%) were diagnosed with concomitant hepatitis B virus (HBV) and HVC infection. Demographic, immunosuppression, survival figures and post-transplant and follow-up data of these patients and negative HBV and HVC patients were recorded.

RESULTS

The overall prevalence of HBV in the recipients was 2.1%. Patient survival was lower and liver disease was the main cause of death in HBV-positive patients. However, in the multivariate analysis the presence of positive HbsAg did not have an independent risk factor for graft loss and patient death. This finding was similar in patients with concomitant HBV and HVC infection. Graft and patient survival were lower in HCV-positive patients and liver disease was the main cause of death. Interestingly, proteinuria and serum creatinine were risk factors for graft loss and patient death. Fortunately, prevalence of HCV in the recipients significantly decreased from 29% in 1990 to 10% in 1998.

CONCLUSIONS

In the last decade in Spain, HBV infection in the recipients, showing an overall prevalence approximately 2%, did not influence graft and patient survival. However, HCV infection in the recipient was associated with lower graft and patient survival, although the prevalence of HCV clearly decreased from 29% in 1990 to 10% in 1998.

Monitorización de las concentraciones plasmáticas de vancomicina en pacientes en hemodiálisis

OBJECTIVE

The aim of this study was to confirm whether patients undergoing dialysis and treated with vancomycin 1 g/week or 500 mg/48 hours reach optimum plasma levels (10-25 mcg/ml).

METHOD

Thirty two patients were included with a total number of 34 infectious events. The most commonly used dose was 1 g/week (67.6% of infectious events), versus 500 mg/48 hours (32.4%). Low ultrafiltration membranes were used more frequently (64.7%) than high ultrafiltration membranes (35.3%).Vancomycin was infused over an one-hour period during the last hour of the hemodialysis session and plasma samples were drawn prior to the beginning of the session. Samples were analyzed using fluorescent polarization immunoassays.

RESULTS

Mean concentration results for the total population did not reach optimum values (10-25 mg/ml). In the group receiving 500 mg/48 hours, optimum mean values were not reached in any of the determinations, whereas in the group receiving 1 g/week, optimum values were reached in the fourth determination. Mean plasma levels of the antibiotic were below optimum values, regardless the type of membrane used, either low or high ultrafiltration.

CONCLUSIONS

Based on the above results, we recommend titration of the vancomycin dose in this group of patients and the administration of a loading dose of 20 mg/kg during the last hour of the hemodialysis session, followed by a maintenance dose of 7 mg/kg after each session, as well as the monitoring of the drug levels in this group of patients.

A comparison of the effects of D-003 and policosanol (5 and 10 mg/day) in patients with type II hypercholesterolemia: a randomized, double-blinded study

The main goal of hypercholesterolemia management for coronary prevention is to reduce serum low-density lipoprotein cholesterol (LDL-C) levels. D-003 is a mixture of high molecular weight aliphatic acids purified from sugarcane wax, while policosanol is a cholesterol-lowering drug purified from the same source, consisting in a mixture of higher aliphatic alcohols. No previous comparative study of both drugs in humans has been reported. This randomized, double-blind study compares the efficacy and tolerability of D-003 and policosanol (5 and 10 mg/day) in patients with type II hypercholesterolemia. After a baseline period, 100 patients were randomized to D-003 or policosanol both at 5 mg/day and 10 mg/day, for 8 weeks. D-003 and policosanol 5 mg/day reduced (p < 0.0001) LDL-C by 26.9% and 20.9%, respectively. These reductions increased with 10 mg/day (35.1% for D-003, 25.1% for policosanol. The reductions of LDL-C achieved with D-003 5 mg/day and 10 mg/day were greater (p < 0.05 and p < 0.001, respectively) than with policosanol. The frequency of patients treated with D-003 (5 mg/day) reaching LDL-C reductions > or = 15% (22/25, 88%) was greater (p < 0.01) than with policosanol (5 mg/day) (19/25, 76%), and the same was true for D-003 10 mg/day (25/25, 100%) and policosanol (22/25, 88%; p < 0.01). D-003 and policosanol (5 mg/day) also lowered (p < 0.001) total cholesterol (TC) (16.2% and 13.5%, respectively), and increased high-density lipoprotein cholesterol (HDL-C) by 15.3% (D-003) and 6.7% (policosanol). At 10 mg/day, D-003 and policosanol reduced (p < 0.001) TC (21.3% and 16.0%, respectively), while HDL-C was increased by 17.3% and 9.8%, respectively, D-003 being more effective than policosanol. Treatments did not affect triglycerides. Both drugs were well tolerated, with D-003 tolerated as well as policosanol. Three patients discontinued the study, none due to adverse events (AEs). Seven patients (three from the D-003 group and four from the policosanol group) experienced mild AEs. In conclusion, D-003 (5 and 10 mg/day) administered to patients with type II hypercholesterolemia was more effective than policosanol in lowering LDL-C and TC, and in increasing HDL-C. D-003 could be useful for treating type II hypercholesterolemia, but this subject deserves further clinical research.

Effects of Addition of Policosanol to??Omega-3 Fatty Acid Therapy on the??Lipid Profile of Patients with Type??II Hypercholesterolaemia

BACKGROUND

Policosanol is a mixture of higher aliphatic primary alcohols purified from sugar-cane wax. The mixture has cholesterol-lowering efficacy, its specific effects being to reduce serum total (TC) and low-density lipoprotein cholesterol (LDL-C), and to increase high-density lipoprotein cholesterol (HDL-C). The effects of policosanol on triglycerides (TG) are modest and inconsistent. Omega-3 fatty acids (FA) from fish oil protect against coronary disease, mainly through antiarrhythmic and antiplatelet effects. Omega-3 FA also have lipid-modifying effects, mostly relating to TG reduction. Thus, potential benefits could be expected from combined therapy with omega-3 FA and policosanol.

OBJECTIVE

To investigate whether combined therapy with omega-3 FA + policosanol offers benefits compared with omega-3 FA + placebo with respect to the lipid profile of patients with type II hypercholesterolaemia.

METHODS

This randomised, double-blind study was conducted in 90 patients with type II hypercholesterolaemia. After 5 weeks on a cholesterol-lowering diet, patients were randomised to omega-3 FA + placebo, omega-3 FA + policosanol 5 mg/day or omega-3 FA + policosanol 10 mg/day for 8 weeks. Omega-3 FA was supplied as 1g capsules (two per day); placebo and policosanol were provided in tablet form. Physical signs and laboratory markers were assessed at baseline and after 4 and 8 weeks on therapy. Drug compliance and adverse experiences (AEs) were assessed at weeks 4 and 8. The primary efficacy variable was LDL-C reduction; other lipid profile markers were secondary variables.

RESULTS

After 8 weeks, omega-3 FA + policosanol 5 and 10 mg/day, but not omega-3 FA + placebo, significantly reduced LDL-C by 21.1% and 24.4%, respectively (both p < 0.0001). Omega-3 FA + policosanol 5 mg/day also significantly lowered TC (12.7%; p < 0.01) and TG (13.6%; p < 0.05), and significantly increased HDL-C (+14.4%; p < 0.001). Omega-3 FA + policosanol 10 mg/day significantly decreased TC (15.3%; p < 0.001) and TG (14.7%; p < 0.01), and significantly increased HDL-C (+15.5%; p < 0.0001). Omega-3 FA + placebo significantly reduced TG (14.2%; p < 0.05) but had no significant effect on other lipid profile variables. The proportion of randomised patients in the omega-3 FA + policosanol 5 or 10 mg/day groups that achieved LDL-C targets or reductions 15% was significantly greater than in the omega-3 FA + placebo group (p < 0.001). Combined therapy with omega-3 FA + policosanol 5 or 10 mg/day resulted in significantly greater changes in LDL-C, TC and HDL-C than treatment with omega-3 FA + placebo, but did not modify the TG response compared with the omega-3 FA + placebo group. Four patients (two in the omega-3 FA + placebo group and two in the omega-3 FA + policosanol 10 mg/day group) withdrew from the study; none of these withdrawals was due to AEs. Two patients reported mild AEs, namely nausea/headache (one in the omega-3 FA + placebo group) and heartburn (one in the omega-3 FA + policosanol 5 mg/day group).

CONCLUSIONS

Policosanol 5 or 10 mg/day administered concomitantly with omega-3 FA 1 g/day improved LDL-C, TC and HDL-C, maintained the reduction in TG attributable to omega-3 FA monotherapy, and was well tolerated. Treatment with omega-3 FA + policosanol could be useful for regulating lipid profile in patients with type II hypercholesterolaemia, but further studies involving larger sample sizes are needed before definitive conclusions can be drawn.

The effect of D-003 (10 mg/day) on biochemical parameters of bone remodelling in postmenopausal women: a randomized, double-blind study

Biphosphonates, which are antiresorptive agents used to treat osteoporosis, inhibit the mevalonate pathway, preventing protein prenylation and inhibiting osteoclast activity. Statins decrease cholesterol biosynthesis by blocking the mevalonate pathway and have been reported to have beneficial effects on bone. D-003 is a mixture of high molecular weight acids purified from sugarcane wax that inhibits cholesterol biosynthesis before mevalonate production. D-003 prevents bone loss and resorption in rats with osteoporosis induced with ovariectomy or corticoids. Biochemical markers of bone turnover are used to monitor the short-term efficacy of antiosteoporotic therapy. This randomized, double-blind, placebo-controlled study was undertaken to investigate the short-term effects of D-003 (10 mg/day) on biochemical markers of bone turnover in postmenopausal women with low bone mineral density (BMD). After 4 weeks on a low-fat diet, 34 women were randomized to D-003 (10 mg/day) or placebo for 6 months. Pre- and post-treatment samples were analyzed for urinary excretion of deoxypyridinoline (DPD)/creatinine (Cr), a marker of bone resorption, and serum bone specific alkaline phosphatase (BSAP), a marker of bone formation. The effects on lipid profile and safety indicators, as well as adverse events (AE), were investigated. D-003 (10 mg/day) lowered urinary excretion of tDPD/Cr versus baseline (20.6%) (p < 0.001) and placebo (33.7%) (p < 0.01), but did not modify serum BSAP. D-003 decreased low-density lipoprotein-cholesterol (LDL-C) (32.8%), total cholesterol (TC) (16.4%) and the TC/high-density lipoprotein-cholesterol (HDL-C) ratio (34.7%), increased HDL-C (30.3%) (p < 0.001) and did not modify triglycerides. The effects on these variables were significant as early as 3 months after treatment initiation. D-003 was well tolerated. Three patients (one in the placebo group and two in the D-003 group) withdrew from the study. Two of these withdrawals were due to AE: abdominal pain (placebo) and heartburn (D-003). Five patients (four in the placebo group [22.2%] and one in the D-003 group [6.3%]) reported mild AE. In conclusion, D-003 (10 mg/day) reduced urinary excretion of tDPD/Cr, a bone resorption marker and did not change serum BSAP, a bone formation marker, while it lowered cholesterol in study patients. These preliminary results suggest that D-003 could be useful in treating postmenopausal women with low BMD. However, the potential value of D-003 in treating or preventing osteoporosis deserves further clinical investigation.

Soil pollution by a pyrite mine spill in Spain: evolution in time

Soil pollution was studied after the spill of the Aznalcóllar pyrite mine between 1998 and 2001, analyzing As, Zn, Cd, Cu and Pb both in total concentrations as well as in soluble and bioavailable forms. The main remediation measures were: clean-up of the tailings and polluted soils, plus application of amendment materials (liming). The results indicate that, after three years, 50-70% of the acidic soils and 25-30% of the basic soils are still highly polluted in total arsenic. The limit of 0.04 mg kg(-1) for water-soluble arsenic is exceeded in 15-20% of all soils. The EDTA-extractable arsenic (bioavailable) exceeds the limit of 2 mg kg(-1) only in the acidic sectors. After clean-up, the homogenization of the upper 20-25 cm of the soils appears to be the most recommended measure in the reduction of pollution.

[Incidence of pain upon injection of a new formula of propofol in a fat emulsion of medium- and long-chain triglycerides]

OBJECTIVE

To study the incidence of pain upon injection of 1% propofol (Propofol-Lipuro 1%, B. Braun, Melsungen, Germany) in a 10% fat emulsion containing equal proportions (50:50) of medium- and long-chain triglycerides.

PATIENTS AND METHODS

The subjects were 600 adult patients scheduled for elective surgery. The use of premedication was left to the discretion of the anesthesiologist. All patients received the study anesthetic injected slowly (20-40 mg per 10 seconds) at a dose of 1.5 to 2.5 mg/Kg. Variables recorded were incidence and type of pain upon administering the anesthetic, the patients' clinical characteristics, premedication administered, and method of venous puncture. Bivariate and multivariate statistical analyses were performed to determine factors associated with the appearance of pain.

RESULTS

The overall incidence of pain upon administration of propofol-lipuro was 27%. Pain was moderate to intense in 9%. Premedication did not affect the incidence of pain with injection. The risk factors that predicted the appearance of pain were injection through a small-caliber catheter (> 18 G) and injection on the dorsal hand (P < 0.05).

CONCLUSIONS

The incidence of pain upon injection of propofol-lipuro is low in comparison with incidence rates reported in the literature for the traditional formula, but administration of the fat emulsion formula through a vein on the dorsal side of the hand or through a venous catheter smaller than 18 G should be avoided. Double-blind randomized controlled trials should be conducted to clarify the advantages that propofol-lipuro seems to offer.

Thermodynamic properties of 1,1,1,2-tetrafluoroethane + polyether mixtures up to 60 MPa

In this work we report several derived thermodynamic properties, the isothermal compressibility (κT), the isobaric thermal expansion coefficient (αp), and the internal pressure (π), and their excess functions (κTE, αpE, and πE) for the refrigerant + lubricant mixtures HFC-134a + triethylene glycol dimethyl ether and HFC-134a + tetraethylene glycol dimethyl ether. These properties have been determined in wide temperature (293.15–373.15 K) and pressure (10–60 MPa) ranges in an effort to better understand the behaviour of these kinds of mixtures and their thermophysical properties as functions of temperature, pressure, and composition. The analysis of the thermodynamic excess properties (negative values for κTE and αpE, positive values for πE) for both systems shows a high degree of interaction between the refrigerant and the synthetic lubricant molecules. Key words: HFC-134a, high pressure, internal pressure, isobaric thermal expansion coefficient, isothermal compressibility, polyglycol ethers, refrigerant–lubricant mixtures.

Fixed contributions designs vs. minimization of global coancestry to control inbreeding in small populations

Populations with small census sizes are at risk because of the loss of genetic variability and the increase of inbreeding and its harmful consequences. For situations with different numbers of males and females, several hierarchical designs have been proposed to control inbreeding through the fixation of individuals' contributions. An alternative method, based on the minimization of global coancestry, has been proposed to determine contributions as to yield of the lowest levels of inbreeding in the population. We use computer simulations to assess the relative efficiency of the different methods. The results show that minimizing the global coancestry leads to equal or lower levels of inbreeding in the short and medium term, although one of the hierarchical designs provides lower asymptotic inbreeding rates and, thus, less net inbreeding in the long term. We also investigate the performance of the alternative methods against departures from the ideal conditions, such as inbred or differentially related base individuals and random failures in the expected contributions. The method of minimization of global coancestry turns out to be more flexible and robust under these realistic situations.

[Incidence and prevalence of autoimmune hepatitis in the area of the Hospital de Sagunto (Spain)]

Thirteen cases of autoimmune hepatitis (AIH) were diagnosed from 1990 to 2003 in the area of the Hospital de Sagunto (Valencia, Spain), which attends a population of 112,003 inhabitants aged more than 14 years (54,622 males and 57,381 females). The diagnostic criteria of the International Autoimmune Hepatitis Group were used and patients who, despite having a probable diagnosis of AIH, presented hepatitis C virus infection were excluded. The diagnosis was probable in one patient and definitive in 12. All patients, 11 females and two males aged 45.9 12.2 years (range: 28-66), were classified as AIH type 1. Among the population aged more than 14 years, the mean annual incidence of AIH was 0.83 cases/100,000 inhabitants (95% CI, 0.44-1.42) (range: 0-2.68), showing a significant trend to increase (b = 0.132; p = 0.019). The incidence was higher in women than in men (RR = 5.24; 95% CI, 1.16-23.62). The mean annual incidence was 1.37 (95% CI, 0.68-2.46) (range: 0-3,49) in women and was 0.26 (95% CI, 0.02-0.96) (range: 0-1.83) in men. By age, the maximum mean annual incidence was observed in the group aged 55-64 years (1.6 cases/100,000 inhabitants). The prevalence of AIH in September 2003 was 11.61 cases/100,000 inhabitants aged more than 14 years (95% CI, 6.78-19.86). The prevalence was 3.66 (95% CI, 1-13.35) in men and was 19.17 (95% CI, 10.70-34.33) in women.