Severe childhood trauma and clinical and neurocognitive features in schizotypal personality disorder.

OBJECTIVE: Literature suggests that childhood trauma increases vulnerability for schizophrenia-spectrum disorders, including schizotypal personality disorder (SPD). Yet, it remains unexplored whether childhood trauma predicts symptom load and the level of neurocognitive functioning in SPD. METHOD: We included 225 individuals with SPD and 127 healthy controls. Childhood trauma was evaluated using the Childhood Trauma Questionnaire, and schizotypal traits were assessed using the Schizotypal Personality Questionnaire. Standard neurocognitive assessments covered six cognitive domains. RESULTS: All types of reported childhood trauma were significantly associated with SPD, in a linear fashion. Severe sexual abuse showed the greatest magnitude of association with higher cognitive-perceptual load (e.g., ideas of reference, odd belief or magical thinking); severe emotional neglect was associated with interpersonal scores (e.g., excessive social anxiety, constricted affect) within the SPD group. SPD individuals who reported severe trauma showed worse cognitive functioning (i.e., working memory, verbal/visual learning and memory, as well as verbal fluency). CONCLUSIONS: Particular severe childhood trauma types were associated with higher cognitive-perceptual and interpersonal symptoms in SPD, along with worse cognitive functioning. These findings highlight the need for clinicians to enquire about childhood trauma in SPD patients, since unaddressed early adverse experiences may carry long-term negative consequences.

Neurocognitive subtypes in patients with bipolar disorder and their unaffected siblings.

BACKGROUND: Our previous work revealed substantial heterogeneity in the cognitive profile of bipolar disorder (BD) due to the presence of three underlying cognitive subgroups characterized as: globally impaired, selectively impaired, or cognitively intact. In an effort to determine whether these subgroups are differentially related to genetic risk for the illness, we investigated whether cognitive deficits were more pronounced in unaffected siblings (UAS) of BD probands within identified clusters. METHODS: Cluster analysis was used to identify cognitive clusters in BD (N = 60). UAS (N = 49) were classified into groups according to their proband sibling's cluster assignment; comparisons were made across all clusters and healthy controls (HCs; N = 71). RESULTS: Three cognitive clusters in BD emerged: a globally impaired (36.7%), a selectively impaired (30%), and a cognitively intact cluster (33.3%). UAS showed a qualitatively similar pattern to their BD siblings; UAS of the globally impaired BD cluster showed verbal memory and general cognitive impairments relative to HCs. In contrast, UAS of the other two clusters did not differ from HCs. CONCLUSIONS: This study corroborates findings from prior work regarding the presence of cognitive heterogeneity in BD. UAS of subjects in the globally impaired BD cluster presented with a qualitatively similar cognitive profile to their siblings and performed worse than all other BD clusters and UAS groups. This suggests that inherited risk factors may be contributing to cognitive deficits more notably in one subgroup of patients with BD, pointing toward differential causes of cognitive deficits in discrete subgroups of patients with the disorder.

Reduced circulating levels of sTWEAK are associated with NAFLD and may affect hepatocyte triglyceride accumulation.

CONTEXT: Non-alcoholic fatty liver disease (NAFLD) is the hepatic manifestation of the metabolic syndrome and is strongly associated with obesity, dyslipidaemia and altered glucose regulation. Previous data demonstrated that low circulating levels of tumour necrosis factor weak inducer of apoptosis (sTWEAK) were associated with obesity, diabetes and insulin resistance, all traits associated with an increased risk of NALFD. Circulating sTWEAK levels are expected to be reduced in the presence of NAFLD. OBJECTIVE: We aimed to explore the relationship between NAFLD and circulating sTWEAK levels in obese patients, and to evaluate the effect of sTWEAK on hepatocyte triglyceride accumulation.Design setting and patients:This is an observational case-control study performed in n=112 severely obese patients evaluated for NAFLD by abdominal ultrasound and n=32 non-obese patients without steatosis. Serum sTWEAK concentrations were measured by ELISA. Multivariable analyses were performed to determine the independent predictors of NAFLD. We analysed TWEAK and Fn14 protein expression in liver biopsies by western blotting and immunohistochemistry. An immortalized primary human hepatocyte cell line (HHL) was used to evaluate the effect of sTWEAK on triglyceride accumulation. RESULTS: We observed a reduction in serum circulating sTWEAK concentrations with the presence of liver steatosis. On multivariable analysis, lower sTWEAK concentrations were independently associated with the presence of NAFLD (odds ratio (OR)=0.023; 95% confidence interval: 0.001-0.579; P<0.022). In human hepatocytes, sTWEAK administration reduced fat accumulation as demonstrated by the reduction in palmitic acid-induced accumulation of triglyceride and the decreased expression of cluster of differentiation 36 (CD36) and perilipin 1 and 2 (PLIN1 and PLIN2) genes. CONCLUSIONS: Decreased sTWEAK concentrations are independently associated with the presence of NAFLD. This is concordant with the observation that TWEAK reduces lipid accumulation in human liver cells.

Life events: a complex role in the timing of suicidal behavior among depressed patients.

Suicidal behavior is often conceptualized as a response to overwhelming stress. Our model posits that given a propensity for acting on suicidal urges, stressors such as life events or major depressive episodes (MDEs) determine the timing of suicidal acts. Depressed patients (n=415) were assessed prospectively for suicide attempts and suicide, life events and MDE over 2 years. Longitudinal data were divided into 1-month intervals characterized by MDE (yes/no), suicidal behavior (yes/no) and life event scores. Marginal logistic regression models were fit, with suicidal behavior as the response variable and MDE and life event score in either the same or previous month, respectively, as time-varying covariates. Among 7843 person-months, 33% had MDE and 73% had life events. MDE increased the risk for suicidal behavior (odds ratio (OR)=4.83, P⩽0.0001). Life event scores were unrelated to the timing of suicidal behavior (OR=1.06 per 100 point increase, P=0.32), even during a MDE (OR=1.12, P=0.15). However, among those without borderline personality disorder (BPD), both health- and work-related life events were key precipitants, as was recurrent MDE, with a 13-fold effect. The relationship of life events to suicidal behavior among those with BPD was more complex. Recurrent MDE was a robust precipitant for suicidal behavior, regardless of BPD comorbidity. The specific nature of life events is key to understanding the timing of suicidal behavior. Given unanticipated results regarding the role of BPD and study limitations, these findings require replication. Of note, that MDE, a treatable risk factor, strongly predicts suicidal behaviors is cause for hope.

Postpartum development of endothelial dysfunction and oxidative stress markers in women with previous gestational diabetes mellitus.

BACKGROUND: Relationships between adhesion molecules (AM), oxidative stress, gestational diabetes mellitus (GDM) and future development of type 2 diabetes mellitus are unclear. AIM: We investigated AM and oxidant/antioxidant markers in women with previous history of GDM. SUBJECTS AND METHODS: Postpartum women with GDM (cases; n = 41) and healthy women (controls; n = 21) had clinical and laboratory variables measured, including indicators of vascular damage (ICAM-1, VCAM-1 and E-selectin), oxidative stress (LPO, GSH and GST) and antioxidant markers (catalase, SOD, GPX and TAC). RESULTS: Previous GDM versus control women presented higher body mass index: 27.4 ± 5.6 versus 23.9 ± 3.6 (p = 0.013); waist circumference: 85.2 ± 12.9 versus 77.5 ± 9.0 (p = 0.017); MetS (WHO definition): 14.6 versus 0 % (p = 0.012); MetS (NCEP-ATPIII definition): 22 versus 0 % (p = 0.002); low HDL: 36.6 versus 9.5 % (p = 0.024); fasting glucose (mmol/L): 5.4 ± 0.6 versus 4.9 ± 0.2 (p < 0.001); glucose 120 min (mg/dL): 105.0 ± 30.2 versus 85.1 ± 14.2 (p = 0.007); fasting insulin (µU/mL): 13.4 ± 8.1 versus 8.4 ± 4.3 (p = 0.004); HOMA index: 3.3 ± 2.3 versus 1.8 ± 1.0 (p = 0.002); HbA1c (%/mmol/mol): 5.4 ± 0.2 versus 5.2 ± 0.2/36 ± 1.4 versus 33 ± 1.4 (p = 0.021); uric acid (mg/dL): 4.1 ± 1 versus 3.5 ± 0.6 (p = 0.009); catalase (nmol/min/mL): 38.7 ± 15.6 versus 28.9 ± 11.1 (p = 0.013). There were no significant differences in hypertension prevalence, lipid fractions, albumin/creatinine ratio and AM. CONCLUSIONS: Women with previous GDM have high catalase levels which correlate positively with glucose intolerance, indicating the potential effect of oxidative stress on postpartum dysglycemic status.

Effectiveness of a specific follow up program for the management of the mental components of post-intensive care syndrome and chronic pain after COVID-19: results from the PAIN-COVID randomized clinical trial.

BACKGROUND: Critical COVID-19 survivors are at risk of developing Post-intensive Care Syndrome (PICS) and Chronic ICU-Related Pain (CIRP). We determined whether a specific care program improves the quality of life (QoL) of patients at risk of developing PICS and CIRP after COVID-19. METHODS: The PAIN-COVID trial was a parallel-group, single-centre, single-blinded, randomized controlled trial. The intervention consisted of a follow up program, patient education on PICS and pain, and a psychological intervention based on Rehm's self-control model in patients with abnormal depression scores (≥8) in the Hospital Anxiety and Depression Scale (HADS) at the baseline visit. QoL was evaluated with the 5-level EQ 5D (EQ 5D 5 L), mood disorders with the HADS, post-traumatic stress disorder (PTSD) with the PCL-5 checklist, and pain with the Brief Pain Inventory short form, the Douleur Neuropathique 4 questionnaire, and the Pain Catastrophizing Scale. The primary outcome was to determine if the program was superior to standard-of-care on the EQ visual analogue scale (VAS) at 6 months after the baseline visit. The secondary outcomes were EQ VAS at 3 months, and EQ index, CIRP incidence and characteristics, and anxiety, depression, and PTSD at 3 and 6 months after baseline visits. CONCLUSIONS: This program was not superior to standard care in improving QoL in critical COVID-19 survivors as measured by the EQ VAS. However, our data can help establish better strategies for the study and management of PICS and CIRP in this population. TRIAL REGISTRATION: # NCT04394169, registered on 5/19/2020.

Insecticide resistance in two Aedes aegypti (Diptera: Culicidae) strains from Costa Rica.

Dengue (family Flaviridae, genus Flavivirus, DENV) and dengue hemorrhagic fever (DHF) are presently important public health problems in Costa Rica. The primary strategy for disease control is based on reducing population densities of the main mosquito vector Aedes aegypti (L.) (Diptera: Culicidae). This is heavily dependent on use of chemical insecticides, thus the development of resistance is a frequent threat to control program effectiveness. The objective of this study was to determine the levels of insecticide resistance and the metabolic resistance mechanisms involved in two Ae. aegypti strains collected from two provinces (Puntarenas and Limon) in Costa Rica. Bioassays with larvae were performed according to World Health Organization guidelines and resistance in adults was measured through standard bottle assays. The activities of beta-esterases, cytochrome P450 monooxygenases, and glutathione S-transferases (GST), were assayed through synergists and biochemical tests, wherein the threshold criteria for each enzyme was established using the susceptible Rockefeller strain. The results showed higher resistance levels to the organophosphate (OP) temephos and the pyrethroid deltamethrin in larvae. The efficacy of commercial formulations of temephos in controlling Ae. aegypti populations was 100% mortality up to 11 and 12 d posttreatment with daily water replacements in test containers. Temephos and deltamethrin resistance in larvae were associated with high esterase activity, but not to cytochrome P450 monooxygenase or GST activities. Adult mosquitoes were resistant to deltamethrin, and susceptible to bendiocarb, chlorpyrifos, and cypermethrin. Because temephos and deltamethrin resistance are emerging at the studied sites, alternative insecticides should be considered. The insecticides chlorpyrifos and cypermethrin could be good candidates to use as alternatives for Ae. aegypti control.

Moral distress among healthcare professionals working in intensive care units in Spain.

OBJECTIVE: To assess moral distress (MD) among Spanish critical care healthcare professionals (HCPs). DESIGN: Cross-sectional, prospective study. SETTING: ICUs in Spain. PARTICIPANTS: HCPs currently working in Spanish ICUs. INTERVENTIONS: A 55-item questionnaire was electronically distributed. MAIN VARIABLES: The questionnaire included work-related and socio-demographic characteristics, the Spanish version of the Measure of Moral Distress for Health Care Professionals (MMD-HP-SPA), and the Hospital Ethical Climate Survey (HECS). RESULTS: In total, 1065 intensive care providers completed the questionnaire. Three out of four validity hypotheses were supported. MD was significantly higher for physicians (80, IQR 40-135) than for nurses (61, IQR 35-133, p=0.026). MD was significantly higher for those clinicians considering leaving their position (78, IQR 46-163 vs. 61, IQR 32-117; p<0.001). The MMD-HP-SPA was inversely correlated with the HECS (r=-0.277, p<0.001). An exploratory factor analysis revealed a four-factor structure, evidencing the patient, team, and system levels of MD. CONCLUSIONS: In the study sample, Spanish intensivists report higher MD than nurses. Strategies to improve ICU ethical climate and to correct other related factors in order to mitigate MD at a patient, team, and system level should be implemented. Both groups of HCPs manifest a relevant intention to leave their position due to MD. Further studies are needed to determine the extent to which MD influences their desire to leave the job.

In vitro activity and in vivo efficacy of posaconazole in treatment of murine infections by different isolates of the Aspergillus terreus complex.

Posaconazole (PSC) is an antifungal drug recommended as an alternative for the treatment of invasive aspergillosis in patients who are refractory or intolerant to primary antifungal therapy. We have evaluated the in vitro activity of PSC against 21 strains of the Aspergillus terreus complex using both broth microdilution and disk diffusion (Neo Sensitabs) methods. PSC showed the same high level of activity against all the strains with the two in vitro methods used. We developed a murine model of disseminated infection to evaluate the efficacy of PSC at 5, 10, or 20 mg/kg of body weight twice a day by using 6 different strains chosen randomly. PSC showed good efficacy, especially at 20 mg/kg, as measured by prolonged survival, tissue burden reduction, histopathology, and lowered galactomannan levels. The PSC levels in serum on the fourth day of treatment were higher than the MICs for the strains tested.

Suicidal ideation and suicide attempts in the United States: 1991-1992 and 2001-2002.

The aim of the study is to compare the prevalence of suicidal ideation and attempts in the United States in 1991-1992 and 2001-2002, and identify sociodemographic groups at increased risk for suicidal ideation and attempts. Data were drawn from the National Institute on Alcohol Abuse and Alcoholism 1991-1992 National Longitudinal Alcohol Epidemiologic Survey (n=42,862) and the 2001-2002 National Epidemiologic Survey on Alcohol and Related Conditions (n=43,093), two nationally representative household surveys of non-institutionalized civilians aged 18 years and older, residing in the United States. The lifetime prevalence of suicide attempts remained unchanged in the United States between 1991-1992 and 2001-2002. Specific groups, namely 18- to 24-year-old white and black women, 25- to 44-year-old white women and 45- to 64-year-old Native American men were identified as being at high risk for suicide attempts. Despite prevention and treatment efforts, the lifetime prevalence of suicide attempts remains unchanged. Given the morbidity and mortality associated with suicide attempts, urgent action is needed to decrease the prevalence of suicide attempts in the United States.

Temephos resistance and esterase activity in the mosquito Aedes aegypti in Havana, Cuba increased dramatically between 2006 and 2008.

Aedes aegypti (L.) (Diptera: Culicidae) control programmes in Cuba rely on the application of the organophosphate temephos for larval control. Hence, the monitoring of resistance to this insecticide is an essential component of such programmes. Here, 15 field populations from different municipalities of Havana City were assayed for resistance to temephos. High levels of resistance were detected in all strains and resistance ratios were highly correlated with esterase activity (P = 0.00001). Populations from three municipalities were tested in both 2006 and 2008; resistance and esterase activities both significantly increased during this 2-year period. Synergist studies demonstrated that neither glutathione transferases nor monooxygenases were associated with the increase in resistance to temephos in this period. The duration of the efficacy of commercial formulations of temephos in controlling Ae. aegypti populations in Havana City was reduced by the high level of temephos resistance observed; hence these data are of clear operational significance for the dengue control programme in Cuba. New integrated strategies to avoid further increases in temephos resistance in Cuba are necessary.

Artificial Neural Network for predicting biosorption of methylene blue by Spirulina sp.

An artificial neural network (ANN) was used to predict the biosorption of methylene blue on Spirulina sp. biomass. Genetic and anneal algorithms were tested with different quantity of neurons at the hidden layers to determine the optimal neurons in the ANN architecture. In addition, sensitivity analyses were conducted with the optimised ANN architecture for establishing which input variables (temperature, pH, and biomass dose) significantly affect the predicted data (removal efficiency or biosorption capacity). A number of isotherm models were also compared with the optimised ANN architecture. The removal efficiency or the biosorption capacity of MB on Spirulina sp. biomass was adequately predicted with the optimised ANN architecture by using the genetic algorithm with three input neurons, and 20 neurons in each one of the two hidden layers. Sensitivity analyses demonstrated that initial pH and biomass dose show a strong influence on the predicted removal efficiency or biosorption capacity, respectively. When supplying two variables to the genetic algorithm, initial pH and biomass dose improved the prediction of the output neuron (biosorption capacity or removal efficiency). The optimised ANN architecture predicted the equilibrium data 5,000 times better than the best isotherm model. These results demonstrate that ANN can be an effective way of predicting the experimental biosorption data of MB on Spirulina sp. biomass.

Moral distress among healthcare professionals working in intensive care units in Spain.

OBJECTIVE: To assess moral distress (MD) among Spanish critical care healthcare professionals (HCPs). DESIGN: Cross-sectional, prospective study. SETTING: ICUs in Spain. PARTICIPANTS: HCPs currently working in Spanish ICUs. INTERVENTIONS: A 55-item questionnaire was electronically distributed. MAIN VARIABLES: The questionnaire included work-related and socio-demographic characteristics, the Spanish version of the Measure of Moral Distress for Health Care Professionals (MMD-HP-SPA), and the Hospital Ethical Climate Survey (HECS). RESULTS: In total, 1065 intensive care providers completed the questionnaire. Three out of four validity hypotheses were supported. MD was significantly higher for physicians (80, IQR 40-135) than for nurses (61, IQR 35-133, p=0.026). MD was significantly higher for those clinicians considering leaving their position (78, IQR 46-163 vs. 61, IQR 32-117; p<0.001). The MMD-HP-SPA was inversely correlated with the HECS (r=-0.277, p<0.001). An exploratory factor analysis revealed a four-factor structure, evidencing the patient, team, and system levels of MD. CONCLUSIONS: In the study sample, Spanish intensivists report higher MD than nurses. Strategies to improve ICU ethical climate and to correct other related factors in order to mitigate MD at a patient, team, and system level should be implemented. Both groups of HCPs manifest a relevant intention to leave their position due to MD. Further studies are needed to determine the extent to which MD influences their desire to leave the job.

[Structural alterations of the smooth muscle and of the EGFR expression and C-kit in congenital pyeloureteral stenosis. Relationship with its pathogenesis]. / Alteraciones estructurales del músculo liso y de la expresión de EGFR y C-kit en la estenosis pieloureteral congénita. Relación con su patogénesis.

PURPOSE: To assess the role that the muscular dysplasia, epidermal growth factor (EGFR) and interstitial cells of Cajal (ICC) C-kit +, may have in the pathophysiology of pyeloureteral stenosis (EPU). MATERIALS AND METHODS: 30 samples were studied UPJ (ureteropelvic junction), with 25 UPJ obstruction and 5 controls. Performed with Masson's trichrome staining and immunohistochemical techniques for smooth muscle actin, EGFR (epidermal growth factor) and CD117 (C-kit) (Dako). We compared the results statistically. RESULTS: The control group was diffuse positivity of EGFR in the muscle layer in samples of EPU was positive in 4%, weak in 16% and negative in 80%. The controls are C-kit + ICC between the muscle cells showed a decreased density in the samples of obstruction. Masson's trichrome highlighted the increase of inter-and intramuscular collagen and attenuated muscle fibers, thinner and individualized, in the inner muscular layer of the cases of EPU also evident with the actin. Differences between groups were statistically significant (p < 0.001). CONCLUSIONS: Our results suggest that dysplastic changes in the muscle layer, the low expression of EGFR and the decrease or absence of C-kit + ICC, may participate in the pathophysiology of UPJ obstruction.

Multiple insecticide resistance in Aedes aegypti (Diptera: Culicidae) from Boyeros municipality, Cuba and associated mechanisms.

In this study, insecticide resistance and the mechanisms responsible were characterized in Ae. aegypti of Boyeros municipality from Havana, Cuba. Boyeros represents a high epidemiological risk because it is located near the Havana International Airport, it is highly urbanized, and it has a large influx of people from endemic countries so that it qualifies as a sentinel site for surveillance. The larvae collected from five areas of this municipality showed resistance to temephos associated with metabolic enzymes. The adult mosquitoes displayed a deltamethrin resistance and less distinctly to other pyrethroids associated with a high frequency of sodium channel gene mutations (F1534C and V1016I), detected for the first time in a field population from Cuba. The presence in the field populations of two insecticide resistance mechanisms represents a limiting factor in the success of the control operations of this vector, so other strategies should be considered to preserve the effectiveness of the insecticides available in public health for vector control in Cuba.

Neurocognition and the Suicidal Process.

Early thinking about cognitive process and suicidal behaviors tended to focus on the immediate situation surrounding the individual - typically the underlying psychiatric condition that was seen as leading to his or her distress. However, we now know that the cognitive processes involved in a range of suicidal thoughts and behaviors can exert a significant impact on the expression or development of these behaviors, even without an environmental stressor or psychiatric condition. In this chapter, we summarize theoretical perspectives that led to this realization and explore the current understanding of the link between cognition and suicide from recent research and clinical findings. We present these findings first by psychiatric disorder, then by cognitive domains, and finally by specific suicidal construct in order to highlight the importance of these factors in determining the role of cognition in the suicidal process.Within and across psychiatric disorders, certain cognitive processes - negativistic thinking, impulsivity, cognitive rigidity, and altered emotional processing - are frequently found to be linked to suicidal thoughts and behaviors. Overall cognitive performance, decreased processing speed, executive dysfunction, and negative biases in memory and attention have also been linked to suicidal thoughts and behaviors. However, these findings do not hold true for all populations. There seems to be a role both for cognitive distortions (such as hopelessness) and neurocognitive deficits (such as poor overall cognitive performance, slower processing speed, and executive dysfunction) in the suicidal process, which warrant further exploration both separately and together.

Interactions between triazoles and amphotericin B in treatment of disseminated murine infection by Fusarium oxysporum.

We have evaluated and compared the efficacies of high doses of amphotericin B (AMB; 3 mg/kg of body weight/day), voriconazole (60 mg/kg), and posaconazole (PSC; 100 mg/kg) alone and combined in a murine model of disseminated infection by Fusarium oxysporum. The combination of AMB with PSC showed the best results, prolonging the survival of mice and reducing their organ fungal loads. This combination might constitute a therapeutic option for those infections where monotherapies fail.

Severity of personality disorders and suicide attempt.

OBJECTIVE: Severity of personality disorders (PDs) may be more useful in estimating suicide risk than the diagnosis of specific PDs. We hypothesized that suicide attempters with severe PD would present more attempts and attempts of greater severity/lethality. METHOD: Four hundred and forty-six suicide attempters were assessed. PD diagnosis was made using the International Personality Disorder Questionnaire--Screening Questionnaire. PDs were classified using Tyrer and Johnson's classification of severity (no PD, simple PD, diffuse PD). Severity/lethality of attempts was measured with the Suicide Intent Scale, Risk-Rescue Rating Scale and Lethality Rating Scale. RESULTS: Attempters with severe (diffuse) PD had more attempts than the other groups. After controlling for age and gender, this difference remained significant only for the younger age group and women. There was no relationship between severity of PDs and severity/lethality of attempts. CONCLUSION: Younger female attempters with severe PD are prone to repeated attempts. However, the severity of PD was not related to the severity/lethality of suicide attempts.

Problem-based learning versus lectures: comparison of academic results and time devoted by teachers in a course on Dentistry in Special Patients.

OBJECTIVES: Problem-Based Learning (PBL) is a teaching-learning technique centred on the complete development of the student. It has been successfully implemented in several universities, notably in the health sciences. The process of creating the European Higher Education Area, initiated in Bologna, encourages European universities to use new methodologies in the teaching-learning process, including PBL. Our objectives were to analyze the results obtained by using PBL with fifth-year Dentistry students. STUDY DESIGN: Comparison of academic results between students receiving lectures and PBL participants, and assessment of differences between them in the time devoted to tasks by students and teachers. RESULTS: PBL participants obtained higher grades compared to those receiving lectures only (p<0.05). The two student groups devoted the same amount of time to this subject but the time distribution of tasks was very different, with PBL students spending more time on group work and analysis of the literature. The teachers devoted much more time to the PBL group. CONCLUSIONS: PBL is a teaching-learning methodology that improves student academic results. PBL diverts student time to more complex tasks but requires a greater commitment from the teachers.