Increased Chamber Resting Tone Is a Key Determinant of Left Ventricular Diastolic Dysfunction

BACKGROUND

Twitch-independent tension has been demonstrated in cardiomyocytes, but its role in heart failure (HF) is unclear. We aimed to address twitch-independent tension as a source of diastolic dysfunction by isolating the effects of chamber resting tone (RT) from impaired relaxation and stiffness.

METHODS

We invasively monitored pressure-volume data during cardiopulmonary exercise in 20 patients with hypertrophic cardiomyopathy, 17 control subjects, and 35 patients with HF with preserved ejection fraction. To measure RT, we developed a new method to fit continuous pressure-volume measurements, and first validated it in a computational model of loss of cMyBP-C (myosin binding protein-C).

RESULTS

In hypertrophic cardiomyopathy, RT (estimated marginal mean [95% CI]) was 3.4 (0.4-6.4) mm Hg, increasing to 18.5 (15.5-21.5) mm Hg with exercise (P<0.001). At peak exercise, RT was responsible for 64% (53%-76%) of end-diastolic pressure, whereas incomplete relaxation and stiffness accounted for the rest. RT correlated with the levels of NT-proBNP (N-terminal pro-B-type natriuretic peptide; R=0.57; P=0.02) and with pulmonary wedge pressure but following different slopes at rest and during exercise (R2=0.49; P<0.001). In controls, RT was 0.0 mm Hg and 1.2 (0.3-2.8) mm Hg in HF with preserved ejection fraction patients and was also exacerbated by exercise. In silico, RT increased in parallel to the loss of cMyBP-C function and correlated with twitch-independent myofilament tension (R=0.997).

CONCLUSIONS

Augmented RT is the major cause of LV diastolic chamber dysfunction in hypertrophic cardiomyopathy and HF with preserved ejection fraction. RT transients determine diastolic pressures, pulmonary pressures, and functional capacity to a greater extent than relaxation and stiffness abnormalities. These findings support antimyosin agents for treating HF.

Invasive management of significant tricuspid regurgitation in clinical practice

BACKGROUND

Tricuspid regurgitation (TR) is a prevalent condition inside valvular heart disease (VHD) with relevant prognosis implications. However, concordance between real management in clinical practice and invasive treatment recommendations of European Society of Cardiology (ESC) guidelines is unknown.

METHODS

A substudy of ESC VHD II survey was performed to evaluate the real treatment of TR compared to the clinical ESC guidelines recommendations published in 2012, 2017 and 2021 was performed. TR cases with surgical indication were divided in 3 groups: 1: severe isolated TR without previous left VHD; 2: moderate/severe TR and concomitant severe left VHD; 3: severe TR plus previous left VHD surgery.

RESULTS

Of 902 patients assessed, 123 had significant TR. Fifty (41%) cases demonstrated ESC guidelines 2012-2017 Class I or IIa recommendations for invasive treatment: 9(18%) of group 1, 37(74%) of group 2 and 4(8%) of group 3. Surgery was performed in 24 patients (48%); 1 in group 1(4%), 22 in group 2(92%) and 1 in group 3(4%). Overall concordance was 48% (group 1: 11%; group 2: 59%; group 3: 25%). Regarding the 2021 ESC guidelines only one patient changed groups with an overall concordance of 47% (group 1: 10%; group 2: 59%; group 3: 25%).

CONCLUSION

Concordance between 2012, 2017 and 2021 ESC guidelines recommendations and clinical practice for TR surgical intervention is low, especially in those without concomitant severe left VHD. These results suggest the need to improve further guideline implementation and alternative treatments, such as percutaneous, which could resolve potential discrepancies in those clinical scenarios.

Evaluating the effectiveness of a comprehensive patient education intervention in a hybrid model of cardiac rehabilitation: A pilot study

Objective

To evaluate the effectiveness of a comprehensive educational intervention in a hybrid model of cardiac rehabilitation in Spain during the COVID-19 pandemic.

Methods

In a prospective pretest-posttest pilot study a pooled sample of patients attending hybrid cardiac rehabilitation in Spain received a culturally-adapted education intervention for 6 weeks. Participants completed surveys at pre- and post-rehabilitation assessing disease-related knowledge, health literacy, adherence to the Mediterranean Diet and self-efficacy. Physical activity was measured by number of steps per day using wearable activity tracking devices. Satisfaction with the educational materials was also evaluated by a survey with a 10 point Likert-type scale and yes/no and open-ended questions.

Results

Eighty-one(99%) participants completed both assessments. There was significant improvement in disease-related knowledge(p < 0.001), physical activity(p < 0.001), and adherence to the diet(p = 0.005) post-rehabilitation. The number of participants that were classified as having “high health literacy skills” increased by 17%. Post-rehabilitation knowledge was associated with education level (ß = 0.430; p = 0.001),pre-rehabilitation knowledge (ß = 0.510; p = 0.002), and high health literacy skills (ß = 0.489; p = 0.01). Educational materials were highly satisfactory to participants.

Conclusion

Significant increases in disease-related knowledge and health behaviors in patients attending hybrid models of cardiac rehabilitation are encouraging results that support the value of implementing comprehensive educational initiatives to programs in Spain.

Innovation

This work presents preliminary evidence of the effectiveness of the first comprehensive education intervention that is open access and culturally adapted to people living with cardiovascular disease in Spain.

Natural History of MYH7-Related Dilated Cardiomyopathy

BACKGROUND

Variants in myosin heavy chain 7 (MYH7) are responsible for disease in 1% to 5% of patients with dilated cardiomyopathy (DCM); however, the clinical characteristics and natural history of MYH7-related DCM are poorly described.

OBJECTIVES

We sought to determine the phenotype and prognosis of MYH7-related DCM. We also evaluated the influence of variant location on phenotypic expression.

METHODS

We studied clinical data from 147 individuals with DCM-causing MYH7 variants (47.6% female; 35.6 ± 19.2 years) recruited from 29 international centers.

RESULTS

At initial evaluation, 106 (72.1%) patients had DCM (left ventricular ejection fraction: 34.5% ± 11.7%). Median follow-up was 4.5 years (IQR: 1.7-8.0 years), and 23.7% of carriers who were initially phenotype-negative developed DCM. Phenotypic expression by 40 and 60 years was 46% and 88%, respectively, with 18 patients (16%) first diagnosed at <18 years of age. Thirty-six percent of patients with DCM met imaging criteria for LV noncompaction. During follow-up, 28% showed left ventricular reverse remodeling. Incidence of adverse cardiac events among patients with DCM at 5 years was 11.6%, with 5 (4.6%) deaths caused by end-stage heart failure (ESHF) and 5 patients (4.6%) requiring heart transplantation. The major ventricular arrhythmia rate was low (1.0% and 2.1% at 5 years in patients with DCM and in those with LVEF of ≤35%, respectively). ESHF and major ventricular arrhythmia were significantly lower compared with LMNA-related DCM and similar to DCM caused by TTN truncating variants.

CONCLUSIONS

MYH7-related DCM is characterized by early age of onset, high phenotypic expression, low left ventricular reverse remodeling, and frequent progression to ESHF. Heart failure complications predominate over ventricular arrhythmias, which are rare.

Association of Genetic Variants With Outcomes in Patients With Nonischemic Dilated Cardiomyopathy

BACKGROUND

The clinical relevance of genetic variants in nonischemic dilated cardiomyopathy (DCM) is unsettled.

OBJECTIVES

The study sought to assess the prognostic impact of disease-causing genetic variants in DCM.

METHODS

Baseline and longitudinal clinical data from 1,005 genotyped DCM probands were retrospectively collected at 20 centers. A total of 372 (37%) patients had pathogenic or likely pathogenic variants (genotype positive) and 633 (63%) were genotype negative. The primary endpoint was a composite of major adverse cardiovascular events. Secondary endpoints were end-stage heart failure (ESHF), malignant ventricular arrhythmia (MVA), and left ventricular reverse remodeling (LVRR).

RESULTS

After a median follow-up of 4.04 years (interquartile range: 1.70-7.50 years), the primary endpoint had occurred in 118 (31.7%) patients in the genotype-positive group and in 125 (19.8%) patients in the genotype-negative group (hazard ratio [HR]: 1.51; 95% confidence interval [CI]: 1.17-1.94; P = 0.001). ESHF occurred in 60 (16.1%) genotype-positive patients and in 55 (8.7%) genotype-negative patients (HR: 1.67; 95% CI: 1.16-2.41; P = 0.006). MVA occurred in 73 (19.6%) genotype-positive patients and in 77 (12.2%) genotype-negative patients (HR: 1.50; 95% CI: 1.09-2.07; P = 0.013). LVRR occurred in 39.6% in the genotype-positive group and in 46.2% in the genotype-negative group (P = 0.047). Among individuals with baseline left ventricular ejection fraction ≤35%, genotype-positive patients exhibited more major adverse cardiovascular events, ESHF, and MVA than their genotype-negative peers (all P < 0.02). LVRR and clinical outcomes varied depending on the underlying affected gene.

CONCLUSIONS

In this study, DCM patients with pathogenic or likely pathogenic variants had worse prognosis than genotype-negative individuals. Clinical course differed depending on the underlying affected gene.

Founder mutation in myosin-binding protein C with an early onset and a high penetrance in males

OBJECTIVE

One of the challenges in hypertrophic cardiomyopathy (HCM) is to determine the pathogenicity of genetic variants and to establish genotype/phenotype correlations. This study aimed to: (1) demonstrate that MYBPC3 c.2149-1G>A is a founder pathogenic variant, (2) describe the phenotype and clinical characteristics of mutation carriers and (3) compare these patients with those with the most frequent pathogenic HCM variants: MYBPC3 p.Arg502Trp/Gln.

METHODS

We reviewed genetic tests performed in HCM probands at our institution. We carried out transcript analyses to demonstrate the splicing effect, and haplotype analyses to support the founder effect of MYBPC3 c.2149-1G>A. Carriers with this mutation were compared with those from MYBPC3 p.Arg502Trp/Gln in terms of presentation features, imaging and outcomes.

RESULTS

MYBPC3 c.2149-1G>A was identified in 8 of 570 probands and 25 relatives. Penetrance was age and sex dependent, 50.0% of the carriers over age 36 years and 75.0% of the carriers over 40 years showing HCM. Penetrance was significantly higher in males: in carriers older than 30 years old, 100.0% of males vs 50.0% of females had a HCM phenotype (p=0.01). Males were also younger at diagnosis (32±13 vs 53±10 years old, p<0.001). MYBPC3 c.2149-1G>A resulted in an abnormal transcript that led to haploinsufficiency and was segregated in two haplotypes. However, both came from one founder haplotype. Affected carriers showed a better functional class and higher left ventricular ejection fraction (LVEF) than patients with MYBPC3 p.Arg502Trp/Gln (p<0.05 for both). Nevertheless, the rate of major adverse outcomes was similar between the two groups.

CONCLUSIONS

MYBPC3 c.2149-1G>A splicing variant is a founder mutation. Affected males show an early onset of HCM and with higher penetrance than women. Carriers show better functional class and higher LVEF than MYBPC3 p.Arg502Trp/Gln carriers, but a similar rate of major adverse outcomes.

Supplementation with Phaseolus vulgaris Leaves Improves Metabolic Alterations Induced by High-Fat/Fructose Diet in Rats Under Time-Restricted Feeding

Time-restricted feeding and food enriched in polyphenols are strategies to prevent or reduce metabolic disorders. Bean leaves (Phaseolus vulgaris L.) are a recognized source of polyphenolic compounds, whose effects on metabolic pathways are not well studied. We evaluated the combined effects of dietary supplementation with Phaseolus vulgaris leaves (10% w/w) (BL) and a 7-h daytime-restricted feeding protocol (RF) under a hypercaloric diet (high fat + high fructose) (HFFD) on the metabolic parameters related to glucose and lipid handling. Adult male Wistar rats were treated for 8 weeks with standard and HFFD diets with or without BL. The results showed that RF improved metabolic alterations induced by HFFD (e.g., hepatic steatosis, increased triacylglycerols, and serum lipoproteins). Supplementation with BL significantly enhanced this effect and downregulated the mRNA expression of carbohydrate and lipid metabolism genes in the liver. These results indicate that dietary supplementation with BL enhances the benefits elicited by RF.

Role of age and comorbidities in mortality of patients with infective endocarditis

PURPOSE

The aim of this study was to analyse the characteristics of patients with IE in three groups of age and to assess the ability of age and the Charlson Comorbidity Index (CCI) to predict mortality.

METHODS

Prospective cohort study of all patients with IE included in the GAMES Spanish database between 2008 and 2015.Patients were stratified into three age groups:<65 years,65 to 80 years,and ≥ 80 years.The area under the receiver-operating characteristic (AUROC) curve was calculated to quantify the diagnostic accuracy of the CCI to predict mortality risk.

RESULTS

A total of 3120 patients with IE (1327 < 65 years;1291 65-80 years;502 ≥ 80 years) were enrolled.Fever and heart failure were the most common presentations of IE, with no differences among age groups.Patients ≥80 years who underwent surgery were significantly lower compared with other age groups (14.3%,65 years; 20.5%,65-79 years; 31.3%,≥80 years). In-hospital mortality was lower in the <65-year group (20.3%,<65 years;30.1%,65-79 years;34.7%,≥80 years;p < 0.001) as well as 1-year mortality (3.2%, <65 years; 5.5%, 65-80 years;7.6%,≥80 years; p = 0.003).Independent predictors of mortality were age ≥ 80 years (hazard ratio [HR]:2.78;95% confidence interval [CI]:2.32-3.34), CCI ≥ 3 (HR:1.62; 95% CI:1.39-1.88),and non-performed surgery (HR:1.64;95% CI:11.16-1.58).When the three age groups were compared,the AUROC curve for CCI was significantly larger for patients aged <65 years(p < 0.001) for both in-hospital and 1-year mortality.

CONCLUSION

There were no differences in the clinical presentation of IE between the groups. Age ≥ 80 years, high comorbidity (measured by CCI),and non-performance of surgery were independent predictors of mortality in patients with IE.CCI could help to identify those patients with IE and surgical indication who present a lower risk of in-hospital and 1-year mortality after surgery, especially in the <65-year group.

Prolactin selectively inhibits the LPS-induced chemokine secretion of human foetal membranes

Background: Inflammation is a condition that jeopardizes the continuity of pregnancy because it increases the secretion of chemokines that favor the migration of leukocytes from maternal and fetal circulations to the cervix, placenta, and the chorioamniotic membranes. During pregnancy, the level of prolactin (PRL) in the amniotic fluid is high; there is evidence to suggest that PRL contributes to maintain a privileged immune environment in the amniotic cavity. We test the effect of prolactin on the secretion profile of chemokines in human fetal membranes.Methods: Nine fetal membranes collected from healthy nonlabouring cesarean deliveries at term. We placed whole membrane explants in a two-chamber culture system. Choriodecidua and amniotic chambers were pretreated with 250, 500, 1000, or 4000 ng/ml of PRL for 24 h, then choriodecidua was cotreated with 500 ng/ml of lipopolysaccharide (LPS) and PRL for 24 h. We used ELISA to measure secreted levels of four chemokines (RANTES, monocyte chemoattractant protein 1 (MCP-1), MIP-1α, and IL-8) in both amnion and choriodecidua regions.Results: In comparison with basal conditions, LPS treatment induced significantly higher secretion of RANTES, MCP-1, and MIP-1α, but not of IL-8. RANTES was mainly produced by choriodecidua and cotreatment with PRL significantly decreased its LPS-induced secretion. MCP-1 was primarily produced by the amnion and its secretion was only inhibited by 4000 ng/ml of PRL. Both membrane regions produced MIP-1α, which was significantly inhibited at 1000 and 4000 ng/ml PRL concentrations. IL-8 showed no significant changes regardless of PRL concentration.Conclusion: PRL inhibits the differential secretion of proinflammatory chemokines by human fetal membranes.

The Multigaussian method: a new approach to mitigating spatial heterogeneities with multichannel radiochromic film dosimetry

The main objective of multichannel radiochromic film dosimetry methods is to correct, or at least mitigate, spatial heterogeneities in the film-scanner response, especially variations in the active layer thickness. To this end, films can also be scanned prior to irradiation. In this study, the abilities of various single channel and multichannel methods to reduce spatial heterogeneities, with and without scanning before irradiation, were tested. Red, green and blue single channel models, two additive channel independent perturbation (CHIP) models and two multiplicative CHIP models were compared with the Multigaussian method. The Multigaussian method is a new approach to multichannel dosimetry, based on experimental findings. It assumes that the probability density function of the response vector formed by the pixel values of the different color channels, including irradiated and non-irradiated scans, follows a multivariate Gaussian distribution. The Multigaussian method provided more accurate doses than the other models under comparison, especially when incorporating the information of the film prior to irradiation. The relative dose differences between reference doses measured with MatriXX and film doses were examined. After applying inter-scan and lateral corrections, the lowest mean absolute errors were 0.8% and 1.0% for the Multigaussian method with and without the information of the scan before irradiation, respectively. Followed by the uniform multiplicative CHIP and red single channel models, using pixel values and net optical density, respectively, both with 1.1%.

Additional value of screening for minor genes and copy number variants in hypertrophic cardiomyopathy

INTRODUCTION

Hypertrophic cardiomyopathy (HCM) is the most prevalent inherited heart disease. Next-generation sequencing (NGS) is the preferred genetic test, but the diagnostic value of screening for minor and candidate genes, and the role of copy number variants (CNVs) deserves further evaluation.

METHODS

Three hundred and eighty-seven consecutive unrelated patients with HCM were screened for genetic variants in the 5 most frequent genes (MYBPC3, MYH7, TNNT2, TNNI3 and TPM1) using Sanger sequencing (N = 84) or NGS (N = 303). In the NGS cohort we analyzed 20 additional minor or candidate genes, and applied a proprietary bioinformatics algorithm for detecting CNVs. Additionally, the rate and classification of TTN variants in HCM were compared with 427 patients without structural heart disease.

RESULTS

The percentage of patients with pathogenic/likely pathogenic (P/LP) variants in the main genes was 33.3%, without significant differences between the Sanger sequencing and NGS cohorts. The screening for 20 additional genes revealed LP variants in ACTC1, MYL2, MYL3, TNNC1, GLA and PRKAG2 in 12 patients. This approach resulted in more inconclusive tests (36.0% vs. 9.6%, p<0.001), mostly due to variants of unknown significance (VUS) in TTN. The detection rate of rare variants in TTN was not significantly different to that found in the group of patients without structural heart disease. In the NGS cohort, 4 patients (1.3%) had pathogenic CNVs: 2 deletions in MYBPC3 and 2 deletions involving the complete coding region of PLN.

CONCLUSIONS

A small percentage of HCM cases without point mutations in the 5 main genes are explained by P/LP variants in minor or candidate genes and CNVs. Screening for variants in TTN in HCM patients drastically increases the number of inconclusive tests, and shows a rate of VUS that is similar to patients without structural heart disease, suggesting that this gene should not be analyzed for clinical purposes in HCM.

Development and psychometric properties of the Suicidality: Treatment Occurring in Paediatrics (STOP) Suicidality Assessment Scale (STOP-SAS) in children and adolescents

BACKGROUND

To create a self-reported, internet-based questionnaire for the assessment of suicide risk in children and adolescents.

METHODS

As part of the EU project 'Suicidality: Treatment Occurring in Paediatrics' (STOP project), we developed web-based Patient Reported Outcome Measures (PROMs) for children and adolescents and for proxy reports by parents and clinicians in order to assess suicidality. Based on a literature review, expert panels and focus groups of patients, we developed the items of the STOP Suicidality Assessment Scale (STOP-SAS) in Spanish and English, translated it into four more languages, and optimized it for web-based presentation using the HealthTracker^TM platform. Of the total 19 questions developed for the STOP-SAS, four questions that assess low-level suicidality were identified as screening questions (three of them for use with children, and all four for use with adolescents, parents and clinicians). A total of 395 adolescents, 110 children, 637 parents and 716 clinicians completed the questionnaire using the HealthTracker^TM, allowing us to evaluate the internal consistency and convergent validity of the STOP-SAS with the clinician-rated Columbia Suicide Severity Rating Scale (C-SSRS). Validity was also assessed with the receiver operating characteristic (ROC) area of the STOP-SAS with the C-SSRS.

RESULTS

The STOP-SAS comprises 19 items in its adolescent, parent, and clinician versions, and 14 items in its children's version. Good internal consistency was found for adolescents (Cronbach's alpha: 0.965), children (Cronbach's alpha: 0.922), parents (Cronbach's alpha: 0.951) and clinicians (Cronbach's alpha: 0.955) versions. A strong correlation was found between the STOP-SAS and the C-SSRS for adolescents (r:0.670), parents (r:0.548), clinicians (r:0.863) and children (r:0.654). The ROC area was good for clinicians' (0.917), adolescents' (0.834) and parents' (0.756) versions but only fair (0.683) for children's version.

CONCLUSIONS

The STOP-SAS is a comprehensive, web-based PROM developed on the HealthTracker^TM platform, and co-designed for use by adolescents, children, parents and clinicians. It allows the evaluation of aspects of suicidality and shows good reliability and validity.

On multichannel film dosimetry with channel-independent perturbations

PURPOSE

Different multichannel methods for film dosimetry have been proposed in the literature. Two of them are the weighted mean method and the method put forth by Micke et al. ["Multichannel film dosimetry with nonuniformity correction," Med. Phys. 38, 2523-2534 (2011)] and Mayer et al. ["Enhanced dosimetry procedures and assessment for EBT2 radiochromic film," Med. Phys. 39, 2147-2155 (2012)]. The purpose of this work was to compare their results and to develop a generalized channel-independent perturbations framework in which both methods enter as special cases.

METHODS

Four models of channel-independent perturbations were compared: weighted mean, Micke-Mayer method, uniform distribution, and truncated normal distribution. A closed-form formula to calculate film doses and the associated type B uncertainty for all four models was deduced. To evaluate the models, film dose distributions were compared with planned and measured dose distributions. At the same time, several elements of the dosimetry process were compared: film type EBT2 versus EBT3, different waiting-time windows, reflection mode versus transmission mode scanning, and planned versus measured dose distribution for film calibration and for γ-index analysis. The methods and the models described in this study are publicly accessible through IRISEU. Alpha 1.1 (http://www.iriseu.com). IRISEU. is a cloud computing web application for calibration and dosimetry of radiochromic films.

RESULTS

The truncated normal distribution model provided the best agreement between film and reference doses, both for calibration and γ-index verification, and proved itself superior to both the weighted mean model, which neglects correlations between the channels, and the Micke-Mayer model, whose accuracy depends on the properties of the sensitometric curves. With respect to the selection of dosimetry protocol, no significant differences were found between transmission and reflection mode scanning, between 75 ± 5 min and 20 ± 1 h waiting-time windows or between employing EBT2 or EBT3 films. Significantly better results were obtained when a measured dose distribution was used instead of a planned one as reference for the calibration, and when a planned dose distribution was used instead of a measured one as evaluation for the γ-analysis.

CONCLUSIONS

The truncated normal distribution model of channel-independent perturbations was found superior to the other three models under comparison and the authors propose its use for multichannel dosimetry.

Effects of seed burial on germination, protein mobilisation and seedling survival in Dodonaea viscosa

Ecological restoration of disturbed areas requires substantial knowledge of the germination of native plants and the creation of novel methods to increase seedling establishment in the field. We studied the effects of soil matrix priming on the germination of Dodonaea viscosa seeds, which exhibit physical dormancy. To this end, we buried both pre-scarified (in H2SO4, 3 min) and non-pre-scarified seeds in the Parque Ecológico de la Ciudad de México. After seeds were unearthed, they were post-scarified for 0, 2, 6 and 10 min and their germination percentages compared to the germination of a control batch of laboratory-stored seeds. For both control and unearthed seeds, the protein pattern was determined in the enriched storage protein fraction in SDS-PAGE gels stained with Coomassie blue. Percentage germination increased as the scarification time increased. Pre-scarification significantly increased percentage germination of post-scarified seeds in relation to the control and non-pre-scarified seeds. In seeds unearthed from the forest site, the buried pre-scarified seeds had relatively high percentage germination, even in the absence of post-scarification treatment. A 48-kDa protein was not found in unearthed, pre-scarified seeds nor in the control germinated seeds, indicating that mobilisation of this protein occurred during soil priming. Burying seeds for a short period, including the beginning of the rainy season, promoted natural priming, which increased protein mobilisation. Functionally, priming effects were reflected in high percentage seedling survival in both the shade house and the field. Seed burial also reduced the requirement for acidic post-scarification.

Total serum cholesterol levels and suicide attempts in child and adolescent psychiatric inpatients

Associations between cholesterol and suicidal behavior in adolescent patients have not been explored in depth. In this study, 66 patients consecutively admitted to a psychiatric inpatient unit following attempted suicide were compared with a control group of 54 patients with no history of suicide attempts. The age range of the sample was from 8 to 18 years old. Cholesterol levels were significantly lower in attempted suicide patients than in controls (p < 0.02), supporting the hypothesis that lower cholesterol levels might be associated with suicidal behavior in patients with similar acute phase of their disorder.

Functional anatomy of aortic regurgitation. Role of transesophageal echocardiography in aortic valve-sparing surgery

INTRODUCTION AND OBJECTIVES

The aim was to evaluate the usefulness of transesophageal echocardiography (TEE) for the preoperative functional anatomical assessment of patients with aortic regurgitation (AR) to identify those eligible for valve-sparing surgery (VSS).

METHODS

We determined the accuracy and diagnostic value of TEE for identifying underlying lesions and mechanisms in 66 patients who underwent surgery for severe AR by comparing TEE findings with those obtained on surgical inspection. The usefulness of TEE for predicting the feasibility of VSS was determined.

RESULTS

The overall diagnostic accuracy of TEE was excellent (87%, kappa=0.82), with valve prolapse being the principle cause of discrepancy between the methods (in 23/27 cases; 85%). Three anatomical forms of dilatation of the ascending aorta (AA) were correctly classified (accuracy >88%; kappa 0.83): supratubal aneurysm (19 patients), aortic root aneurysm (4), and annuloaortic ectasia (24). The mechanism underlying AR was identified with an accuracy of 85% (kappa 0.8) and there was a significant association between the type of mechanism identified by TEE and the success of VSS (P< .001): VSS was successful in 73% of patients with dilatation of a functional annulus (i.e. with tethering), but aortic valve replacement was required in 78% with prolapses, 90% with thickened leaflets with restricted movement, and 100% with perforation. There was also a relationship between the type of aneurysm and the technique required for AA replacement (P=.004).

CONCLUSIONS

Use of TEE enabled the mechanism underlying AR to be accurately identified. There was a high level of agreement with surgical inspection and the technique was useful for predicting the feasibility of VSS and the surgical procedure for AA replacement.

Pediatric Bipolar Disorder: Do we know how to detect it?

OBJECTIVE

To review the literature covering the epidemiology, clinical characteristics, longitudinal course, prognosis and clues for the assessment of the Pediatrics Bipolar Disorder (PBD).

METHOD

A computerized search in PubMed, looking for published articles since 1980.

RESULTS

During the last years, the PBD diagnosis has proliferated largely, with some studies reporting incidences between 1% and 5%. In the past, some researchers reported that atypical symptoms could be more common than the classical symptoms in the PBD. However, current studies confirm the presence of typical mania symptoms in the youngest. Also, they confirm the utility of the diagnostic criteria DSM-IV in this population, with the PBD-NOS as the most prevalent phenotype. Those cases with irritability and without any other maniac symptom are still not clear, but the evidence shows a possible evolution towards others non-bipolar affective disorders. The PBD has high comorbidity, especially with ADHD and Disruptive Behavior Disorders. In the longitudinal evaluation, the PBD cases show high rates of relapse and persistent subsyndromical symptoms. The diagnosis is based in the clinical presentation, with collateral information provided by the family. Screening scales and standardized interview has been developed.

CONCLUSIONS

Now days is possible the diagnosis of PBD, although there is not enough information about the categorization and the longitudinal course of the PBD. Future studies are needed in order to clarify these shadows.

[Postvaricella cerebellar ataxia in children in Costa Rica]

INTRODUCTION

Postvaricella cerebellar ataxia (PVCA) and meningoencephalitis are the most common acute neurological complications of chickenpox. The objective of this study was to describe the clinical presentation, management, and outcome of children hospitalized with PVCA in the only pediatric hospital of this developing country, where routine varicella immunization is not yet available.

METHODS

We performed a retrospective chart review of children aged 1-12 years old admitted to the National Children's Hospital of Costa Rica from January 1997 to June 2004 with a diagnosis of PVCA.

RESULTS

Among the 441 immunocompetent patients admitted for varicella zoster virus-associated complications during this period, 37 (8.4%) had PVCA. Twenty-four of the 37 (64.9%) patients were boys. The mean (range) age was 5 (1-10) years. The median (range) interval from rash onset to admission was 2 (1-3) days. Cerebrospinal fluid analysis was available in 22 (59.5%) patients and was normal in all. Head computed tomography showed cerebral edema in six out of 18 patients (33.3%). Intravenous acyclovir was administered to 23 patients but no significant differences in clinical manifestations or outcomes were observed in treated versus untreated patients. The mean (range) length of ataxia was 4 (1-10) days, and seven (19%) patients were still ataxic on discharge. The mean (range) length of hospital stay was 4.4 (2-11) days. Minor sequelae were documented in 13 out of 24 (54.2%) patients during follow-up visits and telephone contacts.

CONCLUSIONS

PVCA is usually associated with a favorable prognosis; however, neurological sequelae can occur. The real utility of acyclovir treatment and brain imaging studies in these children remains controversial.

Atom and ion chemistry in low pressure hydrogen dc plasmas

The chemical composition of a low-pressure hydrogen dc plasma produced in a hollow cathode discharge has been measured and modeled. The concentrations of H atoms and of H(+), H(2)(+) and H(3)(+) ions were determined with a combination of optical spectroscopic and mass spectrometric techniques, over the range of pressures (p approximately 0.008-0.2 m bar) investigated. The results were rationalized with the help of a zero-order kinetic model. A comparatively high fraction ( approximately 0.1+/-0.05) of H atoms, indicative of a relatively small wall recombination, was observed. Low ionization degrees (<10(-4)) were obtained in all cases. In general, the ionic composition of the plasma was found to be dominated by H(3)(+), except at the lowest pressures, where H(2)(+) was the major ion. The key physicochemical processes determining the plasma composition were identified from the comparison of experimental and model results, and are discussed in the paper.

Ion Chemistry in Cold Plasmas of H2 with CH4 and N2

The distributions of ions and neutrals in low-pressure (approximately 10(-2) mbar) DC discharges of pure hydrogen and hydrogen with small admixtures (5%) of CH(4) and N(2) have been determined by mass spectrometry. Besides the mentioned plasma precursors, appreciable amounts of NH(3) and C(2)H(x) hydrocarbons, probably mostly from wall reactions, are detected in the gas phase. Primary ions, formed by electron impact in the glow region, undergo a series of charge transfer and reactive collisions that determine the ultimate ion distribution in the various plasmas. A comparison of the ion mass spectra for the different mixtures, taking into account the mass spectra of neutrals, provides interesting information on the key reactions among ions. The prevalent ion is H3+ in all cases, and the ion chemistry is dominated by protonation reactions of this ion and some of its derivatives. Besides the purely hydrogenic ions, N(2)H+, NH(4)+, and CH(5)+ are found in significant amounts. The only mixed C/N ion clearly identified is protonated acetonitrile C(2)H(4)N+. The results suggest that very little HCN is formed in the plasmas under study.

The reno-protective effect of hydration with sodium bicarbonate plus N-acetylcysteine in patients undergoing emergency percutaneous coronary intervention: the RENO Study

OBJECTIVES

This study was designed to determine the effectiveness of a protocol for rapid intravenous hydration to prevent contrast-induced nephropathy (CIN) in patients undergoing emergency percutaneous coronary intervention (PCI).

BACKGROUND

Contrast-induced nephropathy frequently complicates PCI, resulting in prolonged hospitalization and increased in-hospital and long-term morbidity and mortality. Little is known regarding prevention of CIN in patients undergoing urgent PCI.

METHODS

We conducted a prospective, controlled, randomized, single-center trial in 111 consecutive patients with acute coronary syndrome undergoing emergency PCI. As part of the hydration therapy, 56 patients (group A) received an infusion of sodium bicarbonate plus N-acetylcysteine (N-AC) started just before contrast injection and continued for 12 h after PCI. The remaining 55 patients (group B) received the standard hydration protocol consisting of intravenous isotonic saline for 12 h after PCI. In both groups, 2 doses of oral N-AC were administered the next day.

RESULTS

The 2 groups were similar with respect to age, gender, diabetes mellitus, and baseline serum creatinine. A serum creatinine concentration >0.5 mg/dl from baseline after emergency PCI was observed in 1 patient in group A (1.8%) and in 12 patients in group B (21.8%; p < 0.001). Acute anuric renal failure was observed in 1 patient (1.8%) in group A and in 7 patients (12.7%) in group B (p = 0.032).

CONCLUSIONS

Rapid intravenous hydration with sodium bicarbonate plus N-AC before contrast injection is effective and safe in the prevention of CIN in patients undergoing emergency PCI.

[Valve repair for bicuspid aortic valve regurgitation: an option?]

Bicuspid aortic valve is the most common form of congenital heart disease. It is associated with both valvular pathology and aortic disease. Aortic regurgitation caused by a bicuspid aortic valve can be corrected by surgical valve repair, which has good short-term results. However, the significant rate of aortic regurgitation recurrence found on long-term follow-up remains a problem, partly because of the progressive aortic dilatation that is characteristic of this disease. We report three different cases of bicuspid aortic valve treated by surgical valve repair at our centre.

Étude comparative de la vitrectomie transconjonctivale sans suture à 25-gauges avec celle à 20-gauges

PURPOSE

The transconjunctival sutureless vitrectomy (TSV 25) is a new technique showing substantial progress.

METHODS

A prospective study of 66 eyes of 66 patients who underwent surgical procedures using the transconjunctival standard vitrectomy system (TSV 25), between June 2004 and June 2005. The results were compared with the results in an equivalent population (66 patients) that underwent vitrectomy with a standard 20-gauge system.

RESULTS

The most important differences between groups were 1) shorter surgical time in the 25-gauge vitrectomy group than in the 20-gauge group, with a mean time of 28.15+/-5.50 min for group 1 and 44.15+/-5.64 min for group 2 (p<0.001) and 2) lower mean postoperative intraocular tension in the first group of patients: in this group, the intraocular tension before surgery was a mean of 16.27+/-1.76 mmHg, decreasing to 12.17+/-1.36 mmHg, with a posterior increase to normal values of 15.06+/-1.66 mmHg at 7 days after surgery and a mean of 16.10+/-1.51 mmHg at 15 days. This decrease was not observed in the group of patients who underwent 20-gauge vitrectomy surgery. The other postoperative complications were similar in both groups except for four cases of anterior proliferation and two cases of fibrinous uveitis in group 2.

CONCLUSION

The transconjunctival sutureless system (TSV 25) decreases surgical time and postoperative inflammation, with optimal postoperative patient comfort, but currently the accurate selection of patients remains important.

Chirurgie combinée phacoexérèse, vitrectomie et implantation chez le patient diabétique avec phacoémulsification versus phacophragmentation

INTRODUCTION

In diabetic patients, we often need to perform cataract and pars plana vitrectomy. Two different techniques are currently valid: 1) phacoemulsification and pars plana vitrectomy and 2)pars plana lensectomy and posterior vitrectomy.

METHODS

Retrospective study of two different groups of type 2 diabetic patients: those receiving 1) phacoemulsification and pars plana vitrectomy or 2) pars plana lensectomy and posterior vitrectomy.

RESULTS

On statistical analysis there were no differences in complications between the two groups. The effect on visual acuity was similar in both groups.

DISCUSSION

The association of cataract surgery and posterior vitrectomy is a valid technique for treating diabetic retinopathy complications. In the present study, the complications of the two techniques were similar, the most important concerning only anterior chamber opening in the first group.

CONCLUSION

The two techniques of cataract extraction and pars plana vitrectomy at the same time have no differences in their results and are valid for treatment of diabetic patients.

[Severe digestive hemorrhage by duodenal injury of Dieulafoy lesion]

The Dieulafoy lesion is a vascular anomaly generally located in proximal stomach. and consist of the presence of an artery of heavy caliber in the submucosa and mucosa, although the definitive diagnosis is anatomopathologic, with the endoscopic examination we can obtained a high precision approach. Is a rare cause of gastrointestinal bleeding although potentially fatal etiology of gastrointestinal hemorrhage. It occurs in fewer than 2% of the episodes of acute digestive hemorrhage. The injury of duodenal Dieulafoy has been communicated in a reduced number of cases and in some of them it has needed surgical treatment. We effectively presented and treat this case of a young man diagnosed in the initial endoscopy and was treated by means of injection of adrenalin and absolute alcohol.

[Catheterization and vascular infection]

The infectious complications that occur following vascular access for catheterization are frequently associated with an unfavourable outcome, mainly because diagnosis is delayed. Although its incidence is low, clinicians should be aware of this complication as the use of invasive procedures is increasing. Here, we report our experience with five patients.

Low-Pressure DC Air Plasmas. Investigation of Neutral and Ion Chemistry

The neutral and charged species present in a direct current (dc) hollow cathode, gas flow, air reactor are experimentally studied by quadrupole mass spectrometry. The degree of ionization of the plasma and the electron mean temperature with decreasing air pressure, for constant discharge current, are measured with a double Langmuir probe. The chemical composition of the plasma changes appreciably over the 3 x 10(-3) to 5 x 10(-2) mbar range investigated: at the lowest pressures studied, O2 dissociation is up to 60% and the concentration of NO is half that of N2; concerning ions, NO+ and N2+ are dominant for the whole pressure range. A kinetic model of the plasma including electrons, neutrals, and positive ions is developed to account for the experimental observations; it is consistent with energy balance and predicts that heterogeneous processes are the main source of NO and that the contribution of ions to the global chemistry of neutrals is of minor significance even for the lowest pressures.

Neuroendocrine dopaminergic regulation of prolactin release in systemic lupus erythematosus: a possible role of lymphocyte-derived prolactin

Prolactin (PRL) secretion by the pituitary is under the control of dopamine. Hyperprolactinemia has been found in patients with systemic lupus erythematosus (SLE) and seems to be associated with clinical activity. T-lymphocytes express PRL and those from SLE patients appear to secrete more PRL than controls. In this study, immuno-(RIA) and bio-(BIO) assayable PRL in both serum and culture media of peripheral blood mononuclear cells (PBMNC) from SLE and control subjects were evaluated in the basal state and in response to 10 mg oral administration of metoclopramide, a dopamine receptor antagonist. Prolactin size heterogeneity in serum and culture media and PRL gene transcription in PBMNC were also studied. Basal serum RIA-PRL, BIO-PRL and the BIO/RIA ratio were similar in both groups. The serum BIO-PRL response after metoclopramide was higher than RIA-PRL in SLE, and this increment was also greater than in control subjects. PBMNC from SLE subjects secreted and produced more BIO-PRL. After metoclopramide, secretion and production of PRL increased only in PBMNC from control women and not in those from SLE patients. Our results demonstrated an increased central dopaminergic tone in SLE and suggest that lymphocyte-derived PRL might contribute to alter the functional activity of the hypothalamic dopaminergic system in SLE attempting to maintain serum PRL within a physiological range.

Aflatoxin B1and its interconverting metabolite aflatoxicol in milk: the situation in Mexico

Between 1996 and 1998, 580 litres of milk in Mexico were surveyed for aflatoxin B(1) (AFB(1)) and its metabolite aflatoxicol (AFL), which are mutagenic and carcinogenic mycotoxins that interconvert AFB(1)-AFL-AFB(1). The seven most consumed brands from different regions of Mexico included pasteurized and ultrapasteurized milk with four different fat levels: whole fat (28-33 g l(-1)), half-skimmed (10-20 g l(-1)), light (1-4 g l(-1)) and with vegetable oil (33 g l(-1)). Aflatoxins in each sample were concentrated with total aflatoxin immunoaffinity columns and quantitated by high-performance liquid chromatography. A milk sample was considered contaminated if it contained >/=0.05 microg l(-1) AFL. Pasteurization and ultrapasteurization of milk did not control contamination with AFL, which was present in 13% of samples at >/=0.05 microg l(-1) and in 8% at >/=0.5 microg l(-1), with a range of AFL from 0 to 12.4 microg l(-1). AFB(1) was present mainly in traces (0-0.4 microg l(-1)). The safest milk in relation to AFL contamination was imported milk powder with vegetable oil. There was a significant correlation between contamination of milk with AFL and the autumn (p<0.0002); the fat content was not significant.

Internal stochastic resonance in the coherence between spinal and cortical neuronal ensembles in the cat

Internal stochastic resonance is a phenomenon in which the coherence of a non-linear system is enhanced by the presence of a particular, non-zero level of noise generated by internal or external sources without a periodic input signal. The aim of this study was to demonstrate the experimental occurrence of internal stochastic resonance in the coherence between spinal and cortical neuronal ensembles. Simultaneous recordings of spinal and cortical evoked potentials were made in the somatosensory system of the anaesthetized cat. Evoked potentials were produced by input noise introduced in the tactile stimulation of the hindpaw skin. Coherence between the spinal and cortical evoked activity recorded during different levels of input noise was calculated. All animals showed distinct internal stochastic resonance like behavior. We found that the mean coherence was an inverted U-like function of the level of input noise with a mean coherence peak of 0.43. To our knowledge, this is the first documented evidence of such phenomenon in an in vivo preparation of the central nervous system.

Stochastic resonance in human electroencephalographic activity elicited by mechanical tactile stimuli

Stochastic resonance (SR) is a phenomenon in which the response of a non-linear system to a weak input signal is optimized by the presence of noise. The aim of this study was to demonstrate the experimental occurrence of SR in electroencephalographic (EEG) activity elicited by mechanical tactile stimuli. Our experiments show that EEG responses evoked by mechanical tactile stimuli in the region overlying the somatosensory cortical area were optimized by the addition of certain noise amplitudes. All subjects showed distinct SR behavior. The signal-to-noise ratio (SNR) of the response evoked by mechanical indentations of the skin was an inverted U-like function of the input noise. As the noise amplitude increased, SNR values became larger. A maximum value was reached with a particular noise amplitude value. Beyond such peak, with higher noise amplitudes, the curve subsided gradually. To our knowledge, this is the first documented evidence that such remarkable phenomenon embodies electrical processes of the human brain. Such behavior might explain related findings described in psychophysical studies.

Amplitude of somatosensory cortical evoked potentials is correlated with spontaneous activity of spinal neurones in the cat

Simultaneous recordings of cortical evoked potentials in the posterior sigmoid gyrus, and spontaneous negative cord dorsum potentials (CDPs) of the L6 lumbar spinal segment, were made in the anaesthetised cat. The electrodes were positioned in cortical and spinal somatosensory regions where the largest spontaneous and evoked negative potentials were detected. Evoked potentials were produced by electrical stimulation to cutaneous nerves or by mechanical stimulation of the hindpaw skin. We found that both electrically and mechanically cortical evoked potentials were facilitated during the spontaneous negative CDPs. The magnitude of such facilitation was proportional to the amplitude of the 'conditioning' spontaneous negative CDPs. This led to a high positive correlation between amplitude fluctuations of spontaneous negative CDPs and fluctuations of the cortical evoked potentials. This observation suggests that transmission of cutaneous sensory information in ascending pathways could be facilitated when dorsal horn spinal neurones are active.

NO donor SIN-1 potentiates monosynaptic reflexes in the cat spinal cord

The effect produced by the nitric oxide donor SIN-1 on monosynaptic reflexes was examined. Experiments were performed on anesthetized, paralyzed and spinalized cats. Lumbar monosynaptic reflexes were produced by stimulation of Ia afferents. I.v. application of SIN-1 (500 microg/kg) produced a mean marked potentiation of 704% of pre-drug control (100%) in the amplitude of monosynaptic reflexes. In addition, in other experiments a concentration-dependent effect on the amplitude of monosynaptic reflexes was observed after microinjections of SIN-1 into the ventral horn (1 microl; 10(-12) - 10(-3) M), with a mean facilitatory effect of 355%. In both cases, the potentiation was reversible 45 min after i.v. or local application of SIN-1. These results provide the first evidence that monosynaptic reflexes can be potentiated by nitric oxide.

Nitric oxide modulates spontaneous cord dorsum potentials in the cat spinal cord

A previous study has shown that lumbar spontaneous cord dorsum potentials (CDPs) are produced by background activity of a neuronal ensemble located in the dorsal horn. Here, the effects produced by intravenous application of the nitric oxide synthase inhibitor L-N(G)-nitro arginine (L-NOARG, 100 microg/kg) and of the nitric oxide donor 3-morpholinosydnonimine hydrochloride (SIN-1, 500 microg/kg) on spontaneous CDPs were examined. Experiments were performed on pentobarbitally anesthetized, paralyzed and spinalized cats. The amplitude of spontaneous CDPs increased after L-NOARG, however, decreased after SIN-1. These observations suggest that electrical activity of dorsal horn neurones generating spontaneous CDPs is dependent on nitric oxide production.

[Zona pellucida antigens in the human ovum: its importance in contraceptive strategies]

The zona pellucida (ZP) is the extracellular matrix surrounding the mammalian oocyte. This matrix consists of three families called ZP1, ZP2 and ZP3. These proteins suffer several posttraductional modifications to give them different immunological and functional properties. In mice has been demonstrated the important role of ZP3 as a receptor of sperm. In the past, research in this field was limited for the difficulty to get enough biological material from different mammalian species, especially from human sources. Recently, several laboratories have expressed ZP recombinant proteins, allowing the study of the proteins under physiologic and pathophysiological conditions, giving the possibility to utilize ZP as a contraceptive target.

Ductal Carcinoma In Situ and Atypical Ductal Hyperplasia of the Breast Diagnosed at Stereotactic Core Biopsy

Stereotactic core needle biopsy (SCNB) allows specific histopathologic diagnoses to be made without surgery and has been demonstrated to be an accurate, cost-effective method of diagnosing breast disease, particularly nonpalpable lesions. However, recent studies have concluded that the diagnosis of atypical ductal hyperplasia (ADH) by means of SCNB has resulted in nearly equal odds that a coexisting malignant lesion will be missed. Furthermore, others have concluded that SCNB diagnosed as DCIS cannot reliably indicate the absence of tumor invasion in surgical excision. Between 1993 and 1998, 1,221 consecutive SCNB of mammographically identified lesions were performed using a 14-gauge automated device with an average of 5.3 cores obtained per lesion. ADH was identified in 19 (1.6%) lesions and DCIS in 89 (7.3%). Surgical biopsy was performed in 89 of these patients and histopathologic results from SCNB and surgical biopsies were reviewed and correlated. In 12 cases of ADH diagnosed by SCNB, surgical biopsy showed ADH in 8 (67%) cases and DCIS in the other 4 (33%) cases. In 77 cases of DCIS diagnosed by SCNB, a surgical biopsy showed DCIS in 55 (71%) cases, 6 more cases (8%) had DCIS with focal microinvasion, and 15 (19%) had invasive ductal carcinoma. In one case no residual tumor was found at surgery. In the author's patient population, the diagnosis of ADH at SCNB indicates high probability of DCIS or residual ADH in the surgical biopsy. The diagnosis of DCIS at SCNB is confirmed in the majority of surgical biopsies; however, a significant number of cases may show microinvasion or invasive carcinoma.

[Vitamin D: implications for health and pregnancy]

Vitamin D gained importance since the discovery of its steroid structure. Vitamin D participates in mineral homeostasis, regulation of gene expression, and cell differentiation. Recent advances in the study of the enzyme involved in the conversion of 25-hydroxyvitamin D3 into 1,25-dihydroxyvitamin D3 (calcitriol), as well as the discovery of it's hormone mechanism of action, have led to a better knowledge and understanding of vitamin D endocrine system, as well as it's implication in health and pregnancy.

Brain-stem auditory evoked potentials in children with perinatal encephalopathies

OBJECTIVE

We sought to describe if neurological damage, in terms of brain lesions, syndrome and syndrome severity led to abnormalities in the brain-stem auditory evoked potentials (BAEPs) in order to provide a profile of children that could be used as an indicator of subsequent neurological sequelae. We analyzed the BAEPs from a group of children having prior evidence of neurological damage and determined the presence of neurological sequelae when the subjects were 3 years old.

METHODS

Brain-stem auditory evoked potentials (BAEPs) were carried out in a group of 154 children with perinatal neurological damage. The children were classified with neurofunctional (clinical and EEG alterations) or organic and neurofunctional brain disease (clinical, EEG and image alteration) and were all followed from the first month of life and serially for 3 years. We used principal component analysis (PCA), clustered analysis and linear correlation to determine association between BAEPs, risk factors and future sequelae.

RESULTS

Latencies of BAEPs decreased significantly with age, and the time of conduction was modified by the presence of neurological damage. All statistical analyses suggested positive and significant associations between risk factors (trophism and condition at birth), and the latencies of waves I, III and V as well as with IPL III-V (interpeak latency) and I-V. PCA showed that IPL I-III was also positively associated with condition at birth, severity of the neurological syndrome and encephalopathy. In addition, we found that the presence and type of sequela reflected changes in the latencies of the waves, as well as IPLs, primarily those of IPL I-III.

CONCLUSIONS

Our results suggest that statistical methods are often needed to analyze neurological damage. The relation between BAEPs, risk factors and neurological sequelae allowed us to obtain a profile of children, which can be then used as an aid in the prognosis of children having a risk of developing neurological sequelae.

[Interaction of work demands in the genesis of mental suffering]

Current working conditions and new forms of work organization are affecting workers' health in numerous ways which can only be explained by more complex theories and methodologies than those used traditionally. The authors analyze some important elements of the work process and the interaction among work demands as determinants of mental and psychosomatic disorders and fatigue (MPDF) among workers in a Mexican industrial plant. The workers studied (n = 830) were male, with a mean age of 32. MPDF represent one-third of the disease burden among these workers. An association was observed with the number of years worked, type of activity, and job area. Job-related demands and work organization, including excessive work, strict supervision, dangerous work, unnatural positions, and intense and hard physical labor were also closely related to these conditions. The most relevant problem is the combination of many different demands. Interaction among the combinations was found to be additive or synergistic. In the latter condition the risk of morbid effects increases beyond merely an additive effect.