Ambush strategy enhances organisms' performance in rock-paper-scissors games

We study a five-species cyclic system wherein individuals of one species strategically adapt their movements to enhance their performance in the spatial rock-paper-scissors game. Environmental cues enable the awareness of the presence of organisms targeted for elimination in the cyclic game. If the local density of target organisms is sufficiently high, individuals move towards concentrated areas for direct attack; otherwise, they employ an ambush tactic, maximising the chances of success by targeting regions likely to be dominated by opponents. Running stochastic simulations, we discover that the ambush strategy enhances the likelihood of individual success compared to direct attacks alone, leading to uneven spatial patterns characterised by spiral waves. We compute the autocorrelation function and measure how the ambush tactic unbalances the organisms' spatial organisation by calculating the characteristic length scale of typical spatial domains of each species. We demonstrate that the threshold for local species density influences the ambush strategy's effectiveness, while the neighbourhood perception range significantly impacts decision-making accuracy. The outcomes show that long-range perception improves performance by over 60%, although there is potential interference in decision-making under high attack triggers. Understanding how organisms' adaptation their environment enhances their performance may be helpful not only for ecologists, but also for data scientists, aiming to improve artificial intelligence systems.

How local antipredator response unbalances the rock-paper-scissors model

Antipredator behavior is a self-preservation strategy present in many biological systems, where individuals join the effort in a collective reaction to avoid being caught by an approaching predator. We study a nonhierarchical tritrophic system, whose predator-prey interactions are described by the rock-paper-scissors game rules. We perform a set of spatial stochastic simulations where organisms of one out of the species can resist predation in a collective strategy. The drop in predation capacity is local, which means that each predator faces a particular opposition depending on the prey group size surrounding it. Considering that the interference in a predator action depends on the prey's physical and cognitive ability, we explore the role of a conditioning factor that indicates the fraction of the species apt to perform the antipredator strategy. Because of the local unbalancing of the cyclic predator-prey interactions, departed spatial domains mainly occupied by a single species emerge. Unlike the rock-paper-scissors model with a weak species because of a nonlocal reason, our findings show that if the predation probability of one species is reduced because individuals face local antipredator response, the species does not predominate. Instead, the local unbalancing of the rock-paper-scissors model results in the prevalence of the weak species' prey. Finally, the outcomes show that local unevenness may jeopardize biodiversity, with the coexistence being more threatened for high mobility.

Developmental trajectories of children with Down syndrome by socio-economic status: the case of Latin America

BACKGROUND

Several studies show that socio-economic status (SES) is related to the developmental trajectories of children with typical development (TD). However, few studies have analysed this relationship regarding children with neurodevelopmental disorders such as Down syndrome (DS). In this paper, we analyse the impact of SES in the neurodevelopmental trajectories of children with DS in comparison with children with TD.

METHOD

Cognitive, language, motor and socio-emotional development were assessed in 31 children with DS between the ages of 15 and 80 months from high to low SES backgrounds. Data from this group were compared with data from a sample of 72 children with TD randomly selected from the Longitudinal Survey of Early Childhood. We analyse and compare these two groups using the developmental trajectories method RESULTS: The results show delayed onsets for the four abilities measured in children with DS compared with children with TD from high to low SES. In the comparison of the developmental trajectories, we found that the differences between the neurodevelopmental trajectories in DS and TD vary according to SES. High SES show differences only in language development, while low SES show significant differences in cognitive, language and socio-emotional development.

CONCLUSIONS

The results indicate that SES is a factor that could impact the developmental trajectories of children with DS. Although the differences between children with DS and with TD are similar at the beginning regardless of SES, the developmental trajectories are slower in children with DS of low SES than in children of high SES. We argue that the differences are related to the complex interaction of several biological and cultural factors associated with SES. Some specific hypotheses about nutrition, health care access, quality of education and parenting practices are presented, but more research in this area is needed to fully understand these results.

Dissociative Amnesia with Fugue vs. Shenjing Shuairuo: A Clinical Case Report. Are DSM-5 Distress Cultural Considerations Truly Transcultural Relevant?

Introduction

We present the case report of a 21-year-old Chinese female, who was brought to the emergency department. We open the debate between the operative criteria stablished by DSM-5 of the clinical entity dissociative amnesia and Shenjing Shuairuo - the Chinese “culture-bound syndrome”.

Objectives

To expose the relevance of the cultural formulation in the clinical evaluation of patients with a different non-Western culture in Psychiatry.

Aims

The Shenjing Shuairuo syndrome (“nervous system weakness”) was originally descripted in China, it has a gradual onset, usually after a stressful event. It involves a minimum 3 of 5 symptoms group: weakness, emotions, excitement, neurological pain and sleep. This complex group of symptoms overlap with dissociative syndrome such as dissociative amnesia.

Methods/results

The cultural formulation interview (CFI) was used for the diagnostic and subsequent treatment of dissociative amnesia with fugue in a different culture patient who met the clinical criteria of this two divergent clinic entities.

Conclusions

In our clinical practice, we will deal with different culture patients, who could present common clinical entities or with the so-called “culture-bound syndromes”. The cultural formulation of the clinical cases will help the clinicians to diagnose and have better treatment's options in clinical manifestations do not correspond to the conventional entities included in mostly Western-based nomenclatures.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

Selective serotonine reuptake inhibitors or dual antidepressants and syndrome of inapropriate antidiuretic hormone secretion: A systematic search

Introduction

Depression is a disease with high prevalence all over the world. Selective serotonine reuptake inhibitors (SSRIs) and dual antidepressants (DA) are worldwide used to treat the different types of depressive episodes. Between the adverse events of these compounds, an unusual but potentially severe side effect is the syndrome of inapropriate antidiuretic hormone secretion (SIADH).

Results and discussion

Several cases published, and an amount of cases series have documented the association of SIADH to the use of SSRIs and DA. All SSRIs and DA are at risk of producing SIADH (fluoxetine, paroxetine, fluvoxamine, sertraline, citalopram, escitalopram, venlafaxine and duloxetine). Old age has been found as a risk factor for developing SIADH. There are not enough data to conclude that other risk factors can play a role in the development of this adverse event. Treatment should include the immediate withdrawal of the antidepressant. The introduction of other antidepressants is controversial, as SIADH has been related with all antidepressive treatments; but the risk of relapse into a depressive episode must be considered also. Between symptomatic treatments, the control of water intake and the use of low doses of loop diuretics can be recommended. Severe cases can be treated with higher doses of loop diuretics and saline hypertonic solution.

Conclusions

SIADH has been related with SSRIs and DA antidepressants and it is an infrequent but severe adverse event. Its risk must be considered when prescribing treatment with them. If this adverse event is produced, the substitution of the antidepressant should be done.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

Chronic Kidney Disease in Renal Transplant Recipients

The aim of the present study was to investigate the utility in renal transplant patients of the guidelines for the diagnosis and classification of chronic kidney disease (CKD) based on the estimated glomerular filtration rate (GFR) elaborated by the Kidney Disease Outcomes Quality Initiative (K/DOQI) of the National Kidney Foundation.

PATIENTS AND METHODS

Four hundred forty-seven cadaveric kidney transplants performed between 1980 and 1994 with graft function at 12 months were included in the study. The GFR was calculated according to the MDRD equation.

RESULTS

The mean GFR at 12 months was 54.5 +/- 20.3 mL/min/1.73 m(2): 23 patients (5.1%) had a GFR > or =90 mL/min/1.73 m(2); 136 patients (30.6%), 60-89; 246 (54.7%), 30-59; 35 patients (7.8%), 15-29; and 7 patients (1.6%), GFR <15. Similar distribution of CKD stages was observed at 5 and 10 years. Unadjusted graft survival at 10 years was better among patients with a higher GFR at 12 months: 87% in patients with GFR >90 mL/min/1.73 m(2); 83% of GFR 60-89 mL/min/1.73 m(2); 63%, GFR 30-59 mL/min/1.73 m(2); and 23%, GFR <30 mL/min/1.73 m(2) (P < .001). The association between GFR and graft survival persisted when adjusted by the age and gender of the recipients and donors, time on dialysis, body mass index, immunosuppression, delayed graft function, rejection, and HLA mismatches. The prevalence of complications, such as anemia, hypertension, dyslipidemias, and number of drugs increased as GFR declined.

CONCLUSIONS

More than 60% of recipients presented chronic kidney disease. GFR was a predictive factor for graft survival at 10 years. The classification of renal transplant patients by CKD stages may help to identify patients with increased risk of graft loss and also to design strategies to improve outcomes.

Lumbar Bone Mineral Density After Kidney Transplantation: A Three-Year Prospective Study

Osteopenia is a common complication after transplantation. However, prospective long-term studies are scarce and most were performed in patients on cyclosporine and high-dose steroids. In 65 patients with functioning grafts, 41 males and 24 females, 50 on tacrolimus-based immunosuppression and 15 on cyclosporine-based immunosuppression, bone mineral density (BMD) was measured in the lumbar spine (L2-L4) and femoral neck (FN) using dual X-ray absorptiometry (DEXA) in the first month after transplantation (baseline) and at 1, 2, and 3 years. At baseline, BMD was similar to the control population both in L2-L4 (z score = -0.421) and in FN (z score = -0.518). During the follow-up, 3 types of patterns were identified: BMD increased in L2-L4 in 25 patients (38.5%), remained stable in 20 patients (30.8%), and decreased in 20 patients (30.8%). BMD losses appeared mainly during the first year (0.964 +/- 0.162 baseline; 0.904 +/- 0.161 at 1 year, 0.886 +/- 0.140 at 3 years; analysis of variance [ANOVA] P < .001). However, the improvement was maintained throughout the follow-up (0.860 +/- 0.176 g/cm2 at baseline; 0.901 +/- 0.161 at 1 year; 0.954 +/- 0.178 at 3 years; ANOVA P < .001) and there was a parallel increase of BMD in FN (0.712 +/- 0.144 at baseline; 0.744 +/- 0.249 at 1 year; 0.826 +/- 0.184 at 3 years; ANOVA P < .01). There were no differences between both groups in graft function, intact parathyroid hormone (iPTH) levels, number of postmenopausal women, or steroid doses. About one third of patients had bone loss during the first year after transplantation. We were unable to identify any risk factor for this complication in patients on low-dose steroids.

Influence of immunosuppression on the prevalence of cancer after kidney transplantation

The prevalence of cancer in renal transplant patients is greater than in the general population. It is influenced by demographic and ethnic characteristics. We performed a retrospective study of 793 patients who received 872 kidney transplants at our center during 23 years. The age at transplantation was 41.4+/-14.0 years, the follow up 75.4+/-69.4 months. The cohorts include 203 patients treated with azathioprine-prednisone; 510, cyclosporine-based therapy; and 159, tacrolimus-based therapy. There were 95 patients (10.9%) who developed at least one neoplasm with 9 having more than one type of tumor. The incidence was of 17.3 cases per 1000 patients-years. Forty-four (46.3%) had skin cancer, 8 (8.4%) Kaposi sarcoma and 43 (45.3%) a non-skin cancer. Seven of eight patients with Kaposi sarcoma were on CsA therapy. The risk of developing a neoplasm at 5, 10, and 15 years was 8%, 17%, and 30% respectively. In a multivariate analysis, the risk factors associated with neoplastic diseases were older age (OR=1.061; 95% CI 1.039-1.084; P=.000), male sex (OR=2.658; 95% CI 1.536-4.599; P=.000), length of follow-up (OR=1.121; 95% CI 1.073-1.172; P =.000), and immunosuppression with CsA (OR=4.448; 95% CI 1.334-14.764; P=.015). Cancer was the cause of death in 26 patients, the fourth most common cause after cardiovascular disease, infection, and liver failure. We conclude that malignancies are an important cause of morbidity and mortality among transplant patients. Special attention must be devoted to older male patients with a long-term follow up to develop preventive and surveillance strategies.

Comparison of C0 and C2 cyclosporine monitoring in long-term renal transplant recipients

Recent data show that monitoring cyclosporine A (CsA) concentrations with 2-hour postdose levels (C2) correlates with the incidence of rejection and graft outcome in de novo renal transplant patients. The purpose of the present work was to evaluate the advantage of C2 monitoring after the first year of kidney transplantation. We studied 161 patients, 96 on CsA-prednisone and 65 on triple therapy (Aza or MMF) who had been transplanted for a mean of 103+/-44 months. Mean serum creatinine (SCr) was 1.65+/-0.69 mg/dL, mean C0 was 174+/-44, and C2 was 667+/-194 ng/mL. Patients were classified according to C2 values: >850 (n=29), between 850 and 450 (n=109), and <450 (n=23) ng/mL. Patients with C2 <450 ng/mL displayed higher SCr values (1.97+/-0.99; 1.59+/-0.51; 1.52+/-0.4 mg/dL; P<.001), received lower CsA doses (172+/-54; 207+/-54; 227+/-56 mg/d, P<.01), showed lower C0 levels (155+/-48; 172+/-41; 199+/-45 ng/mL; P< .001), and included more patients on triple therapy (54.5%; 44%; 17.2%; P<.05). We found weak correlations between C0 and C2 (r=0.37), between C2 and CsA dose (r=0.36), and between C0 and SCr (r=-0.37). Among 117 patients followed up for 1 year with several C0 and C2 measurements, the coefficient of variation of C0 was 17% and of C2 was 21%. Graft functional deterioration occurred in 16 patients independent of the differences among the C2 groups, but 7 recipients (43.7%) had C0 <150 ng/mL and C2/C0 >5. We conclude that C2 in monitoring stable patients needs further evaluation.

Neurospora crassa mutant impaired in glutamine regulation

The final products of the catabolism of arginine that can be utilized as nitrogen sources by Neurospora crassa are ammonium, glutamic acid, and glutamine. Of these compounds, only glutamine represses arginase and glutamine synthetase. We report here the isolation and characterization of a mutant of N. crassa whose arginase, glutamine synthetase, and amino acid accumulations are resistant to glutamine repression (glnI). This mutant has a greater capacity than the wild type (glns) to accumulate most of the arginine and some of the glutamine in osmotically sensitive compartments while growing exponentially. Nonetheless, the major part of the glutamine remains soluble and metabolically available for repression. We propose that the lower repression of glutamine synthetase by glutamine in this mutant could be a necessary condition for sustaining the higher flow of nitrogen for the accumulation of amino acids observed in ammonium excess and that, if glutamine is the nitrogen signal that regulates the arginine accumulation of the vesicle, the glnr mutant has also escaped this control. Finally, in the glnr mutant, some glutamine resynthesis is necessary for arginine biosynthesis and accumulation.