Retrograde viral transduction of cortical pyramidal neurons from the spinal cord

PURPOSE

The primary motor pathway, the corticospinal tract, is a major target for spinal cord regeneration studies. One way of improving the regeneration of corticospinal axons is to introduce regeneration-associated genes into cortical motor neurons using viral vector delivery.

METHODS

We used an engineered Herpes Simplex virus (HSV1) with the EF1alpha promoter encoding either LacZ or GFP to transduce cortical neurons through retrograde transport following the injection of vector into adult rat striatum or spinal cord. After three-days to one-month post-injection, sections of brain and spinal cord were viewed with fluorescence microscopy or processed for LacZ histochemistry.

RESULTS

Many layer V motor cortical neurons were transduced following striatal injections. These were not corticospinal neurons as they were not fluorogold-labelled following tracer injection into spinal cord. Corticospinal neurons in both hemispheres were, however, transduced following direct vector injections into the dorsal column of spinal cord, yielding 250-400 transduced corticospinal neurons per animal. No non-pyramidal neurons or thalamic neurons were transduced by spinal injections.

CONCLUSIONS

Therefore, this HSV1.EF1alpha vector is highly effective for the transduction of corticospinal neurons without direct injection into the brain and could be used to introduce regeneration-relevant genes into these neurons with the aim of regenerating the corticospinal tract.

Toscana virus meningitis in Portugal, 2002-2005

Toscana virus infection is endemic in Italy, but has also been documented in other Mediterranean countries. Our aim was to investigate the occurrence of Toscana virus (TOSV) meningitis in children and young adults in a metropolitan area in the north of Portugal. Cerebrospinal fluid samples from 308 patients with the diagnosis of meningitis and with negative bacterial culture were tested for enteroviruses and herpesviruseses by reverse transcription PCR. Those samples that proved negative for enterovirus and herpesvirus were tested for Toscana virus with a commercial reverse transcription nested PCR assay. In total, we investigated 106 samples, collected between May and September during the four-year period between 2002 and 2005 from patients younger than 30 years old. Toscana virus was the cause of meningitis in six (5.6%) of the cases, three children and three young adults. All had a benign course and self-limited disease. Since a first case report of TOSV infection 1985 and another in 1996, both in foreign tourists, these six cases of Toscana virus meningitis are, to our knowledge, the first diagnosed in Portuguese inhabitants, and they underline the need for more studies on the prevalence of this virus in Portugal.

[Breastfeeding: prevalence and determinant factors]

Breastfeeding is the best way of feeding the baby for the first six months of life. However, in Portugal the abandonment rate of breastfeeding is very high during the baby first's months of life. The aim of this study was to assess prevalence of breastfeeding and to identify related factors during the six months after delivery, as socio demographic variables and life styles. We conducted a cohort study at the Maternity of the Hospital Santa Maria. A standard questionnaire was applied to 475 women after delivery, at three and six months postpartum. We studied socio demographics aspects, life styles and the way of feeding during the six months after delivery. Multivariate analysis was performed. The women studied (mean age of 29.8 +/- 5,4 years), 52.2% were primiparous, 86.1% were Caucasian, 40% had a high school degree and 33% had a University degree. Four hundred and sixty (96.8%) received prenatal care. The mean gestational age was 38.8 +/- 2 weeks and the birth weight was 3198.3 +/- 545.3 g. At the discharge 91% were breastfeeding (77% exclusively), 54.7% at third month and 34.1% at sixth month. The main causes pointed for abandoning breastfeeding were insufficient milk production, bad sucking and return to work. The milk formula introduction was in 68.6% cases by medical recommendation. The decision in maintenance breastfeeding at third and sixth months was correlated with a previous positive breastfeed experience, high educational level, healthy lifestyles, as non-smoking, regular physical activity, and information about advantage of breastfeed for mother health. Information about breastfeeding was received by media, friends, family and only 9% by health professionals. Fifty (13%) women had no information about breastfeeding. Although breastfeeding rate at discharge was high, there was an important rate of abandonment at third and sixth month. Healthy lifestyles, high educational level, a previous positive breastfeed experience had a positive influence in breastfeeding. Understanding attitudes towards pregnancy and breastfeeding can lead to new strategies for its promotion and maintenance.

Conjugated linoleic acid in diets for large-size rainbow trout (Oncorhynchus mykiss): effects on growth, chemical composition and sensory attributes

The effects of graded levels (0 %, 0·5 %, 0·75 and 1 %) of dietary conjugated linoleic acid (CLA) were assessed on 97 g rainbow trout. Fish were fed to satiation twice a day for 12 weeks. At the end of the experiment, all groups of fish weighed more than 250 g and no significant differences were detected in growth performance, feed conversion, nutrient or energy utilisation or body composition between treatments. A decrease in liver lipid content resulted from including CLA and was accompanied by a reduction in malic enzyme activity. The muscle saturated acid and PUFA content did not vary between dietary treatments, despite the increasing concentration of stearic acid and CLA. In the liver, however, both fractions increased significantly with dietary CLA. Moreover, the MUFA decreased significantly in both muscle and liver. CLA was incorporated into tissue lipids, with levels in flesh (2·1–4·2 %) being 2-fold higher than in liver (0·8–1·9 %). In muscle, the percentage of cis-9, trans-11 isomer ranged from 39·5 % to 41·8 % and that of trans-10, cis-12 isomer from 31·4 % to 33·4 % of total CLA. The incorporation of CLA isomers in the liver varied with dietary treatment, and the cis-9, trans-11 isomer seemed to be more efficiently incorporated than trans-10, cis-12. Sensory data indicated slight-to-moderate differences between the trout fed with and without CLA. The present results suggest that 250 g rainbow trout can incorporate CLA in both muscle and liver, contributing to the production of a functional food.

The role of adrenergic receptor polymorphisms in heart failure

The main function of the cardiac adrenergic system is to regulate cardiac work both in physiologic and pathologic states. A better understanding of this system has permitted the elucidation of its role in the development and progression of heart failure. Regardless of the initial insult, depressed cardiac output results in sympathetic activation. Adrenergic receptors provide a limiting step to this activation and their sustained recruitment in chronic heart failure has proven to be deleterious to the failing heart. This concept has been confirmed by examining the effect of beta-blockers on the progression of heart failure. Studies of adrenergic receptor polymorphisms have recently focused on their impact on the adrenergic system regarding its adaptive mechanisms, susceptibilities and pharmacological responses. In this article, we review the function of the adrenergic system and its maladaptive responses in heart failure. Next, we discuss major adrenergic receptor polymorphisms and their consequences for heart failure risk, progression and prognosis. Finally, we discuss possible therapeutic implications resulting from the understanding of polymorphisms and the identification of individual genetic characteristics.

Kinetic properties of wild-type and altered recombinant amidases by the use of ion-selective electrode assay method

A novel assay method was investigated for wild-type and recombinant mutant amidases (EC 3.5.1.4) from Pseudomonas aeruginosa by ammonium ion-selective electrode (ISE). The initial velocity is proportional to the enzyme concentration by using the wild-type enzyme. The specific activities of the purified amidase were found to be 88.2 and 104.2 U mg protein(-1) for the linked assay and ISE methods, respectively. The kinetic constants--Vmax, Km, and Kcat--determined by Michaelis-Menten plot were 101.13 U mg protein(-1), 1.12x10(-2) M, and 64.04 s(-1), respectively, for acrylamide as the substrate. On the other hand, the lower limit of detection and range of linearity of enzyme concentration were found to be 10.8 and 10.8 to 500 ng, respectively, for the linked assay method and 15.0 and 15.0 to 15,000 ng, respectively, for the ISE method. Hydroxylamine was found to act as an uncompetitive activator of hydrolysis reaction catalyzed by amidase given that there is an increase in Vmax and Km when acetamide was used as the substrate. However, the effect of hydroxylamine on the hydrolysis reaction was dependent on the type of amidase and substrate involved in the reaction mixture. The degrees of activation (epsilon(a)) of the wild-type and mutant (T103I and C91A) enzymes were found to be 2.54, 12.63, and 4.33, respectively, for acetamide as the substrate. However, hydroxylamine did not activate the reaction catalyzed by wild-type and altered (C91A and W138G) amidases by using acrylamide and acetamide, respectively, as the substrate. The activating effect of hydroxylamine on the hydrolysis of acetamide, acrylamide, and p-nitrophenylacetamide can be explained by the fact that additional formation of ammonium ions occurred due to the transferase activity of amidases. However, the activating effect of hydroxylamine on the hydrolysis of p-nitroacetanilide may be due to a change in conformation of enzyme molecule. Therefore, the use of ISE permitted the study of the kinetic properties of wild-type and mutant amidases because it was possible to measure initial velocity of the enzyme-catalyzed reaction in real time.

Evaluation of candidate probiotic strains for gilthead sea bream larvae (Sparus aurata) using an in vivo approach

AIMS

The aim of this study was to evaluate the effect of six bacterial strains on gilthead sea bream larvae (Sparus aurata).

METHODS AND RESULTS

Six bacterial strains isolated from well-performing live food cultures were identified by sequencing fragments of their 16s rDNA genome to the genus level as Cytophaga sp., Roseobacter sp., Ruergeria sp., Paracoccus sp., Aeromonas sp. and Shewanella sp. Survival rates of gilthead sea bream larvae transferred to seawater added these bacterial strains at concentrations of 6 +/- 0.3 x 10(5) bacteria ml(-1) were similar to those of larvae transferred to sterilized seawater and showed an average of 86% at 9 days after hatching, whereas, survival rates of larvae transferred to filtered seawater were lower (P < 0.05), and showed an average of 39%, 9 days after hatching.

CONCLUSION

Several bacterial strains isolated from well-performing live food cultures showed a positive effect for sea bream larvae when compared with filtered seawater.

SIGNIFICANCE AND IMPACT OF THE STUDY

The approach used in this study could be applied as an in vivo evaluation method of candidate probiotic strains used in the rearing of marine fish larvae.

Transbronchial administration of adenoviral-mediated interleukin-10 gene to the donor improves function in a pig lung transplant model

Interleukin-10 (IL-10) gene transfection of donor lungs prior to transplantation is an attractive strategy to reduce ischemia-reperfusion induced lung injury. However, experimental data with gene therapy in large animal models of lung transplantation are generally lacking. We have developed a simple clinically applicable technique for adenoviral-mediated gene delivery of human IL-10 to the lung of large animals that provides homogenous gene expression after 12-24 h of transfection. Using this technique of gene delivery, we have studied the dynamics of adenoviral gene delivery to the lung in the setting of lung transplantation. Although there is a persistent inflammatory response to the adenoviral vector, we achieved significant expression of human IL-10 in lung tissue before lung retrieval to obviate the deleterious impact of the adenoviral vector on the donor lung. The administration of adenoviral-mediated human IL-10 to the donor lung reduced ischemia-reperfusion injury and improved graft function after lung transplantation in this pig lung transplantation model. Transfection of adenoviral-mediated human IL-10 to the donor lung prevented the release of inflammatory cytokines such as IL-6 in lung tissue and plasma. We have demonstrated that IL-10 gene therapy has significant potential to prevent or treat the inflammatory response associated with ischemia-reperfusion injury in lung transplantation. In the future, IL-10 gene therapy could also be used for immunomodulation or tolerance induction.

Body surface area estimation and its impact on predicting appendicular skeletal muscle mass with a mechanistic model based on the Reference Man

The purpose of this study was to analyze the difference between the equations presented by Du Bois and Du Bois (1916) and Livingston and Lee (2001), used to estimate body surface area (BSA) and its impact on predicting appendicular skeletal muscle mass (ASMM) in adults, using a model based on the Reference Man (Fuller et al. 1992). Subjects were 666 Caucasian women (44.3+/-15.2 years, 63.7+/-10.5 kg, 1.57+/-0.07 m, 26.0+/-4.3 kg/m(2)) and 316 Caucasian men (42.8+/-15.4 years, 79.8+/-12.5 kg, 1.72+/-0.07 m, 26.8+/-3.8 kg/m(2)). Dual-energy X-ray absorptiometry was used to assess fat mass and fat-free mass. Du Bois's and Livingston's BSA equations were used to calculate ASMM according to Fuller's method. As compared to the new Livingston equation, Du Bois's equation underestimated ( p<0.05) BSA in women (-0.08 m(2)) and in men (-0.06 m(2)). On the other hand, ASMM was overestimated in the arms, legs, and total body with Du Bois's equation. This effect was of greater magnitude in obese subjects.

Haplotype study of microsatellites flanking the t(15;17) breakpoint in acute promyelocytic leukemia patients from North Portugal

A higher frequency of acute promyelocytic leukemia (APL) has been noted in countries of Southern Europe and among 'Latino' patients of the United States with acute myeloid leukemia (AML). In order to discover whether there is any genetic predisposition to the disease, we analyzed microsatellites flanking PML and RARalpha genes in 29 t(15;17) APL patients from North Portugal and compared them with a control group of 123 healthy individuals. Fluorescent PCR products were analyzed using an automated capillary electrophoresis system and allele and haplotype frequencies of the two populations were determined. No significant differences were found, suggesting the same genetic origin of patients and healthy individuals. As suggested by the four microsatellites screened, MSI (microsatellite instability) does not explain the increased incidence of t(15;17) APL in this Portuguese population. These results intend to be a new approach to the study of APL, reflecting the particularity of the disease.

Patient safety in guideline-based decision support for hypertension management: ATHENA DSS

The Institute of Medicine recently issued a landmark report on medical error.1 In the penumbra of this report, every aspect of health care is subject to new scrutiny regarding patient safety. Informatics technology can support patient safety by correcting problems inherent in older technology; however, new information technology can also contribute to new sources of error. We report here a categorization of possible errors that may arise in deploying a system designed to give guideline-based advice on prescribing drugs, an approach to anticipating these errors in an automated guideline system, and design features to minimize errors and thereby maximize patient safety. Our guideline implementation system, based on the EON architecture, provides a framework for a knowledge base that is sufficiently comprehensive to incorporate safety information, and that is easily reviewed and updated by clinician-experts.

School dropout and conduct disorder in Brazilian elementary school students

OBJECTIVES

To evaluate the association between DSM-IV conduct disorder (CD) and school dropout in a sample of students from the third and fourth elementary grades at state schools in the capital of the southernmost state of Brazil.

METHODS

In this case-control study, students that dropped out of schools (n = 44) and a control group who continued attending schools (n = 44) were assessed for CD and other prevalent mental disorders, using the Schedule for Affective Disorders and Schizophrenia for School Age Children, Epidemiological Version (K-SADS-E).

RESULTS

The prevalence of DSM-IV CD was significantly higher in the school-dropout group than in control subjects (P < 0.001), both in the entire sample and in a subsample including only subjects under age 12 years (P = 0.001). Also, the odds ratio (OR) for school dropout was significantly higher in the presence of DSM-IV CD, even after controlling for potential confounding factors (age, estimated IQ, school repetition, family structure, and income) (P < 0.01).

CONCLUSION

Our results extend to children and young adolescents previous findings from studies of older adolescents, suggesting an association between school dropout and CD.

Early and medium term results of tailored therapy for heart failure

Patients (pts) with advanced chronic heart failure, in NYHA functional class IV, refractory to conventional medical therapy, show a poor short-term survival prognosis. Heart transplant remains the therapy of choice but it can currently be performed in only a minority of pts. Therapy tailored to hemodynamic goals has been suggested as a potential alternative for patients with advanced congestive heart failure. Intravenous and, subsequently, oral vasodilators (v) and diuretics (d) are titrated, in order to achieve specific hemodynamic parameters: systolic arterial pressure (SAP) > 80 mmHg, pulmonary wedge pressure (PWP) < 15 mmHg, right atrial pressure (RAP) < 8 mmHg, and systemic vascular resistance (SVR) < 1200 dynes.sec.cm-5.

AIM

To assess short and medium term (two years) results of a tailored therapy management program for treatment of patients with advanced heart failure.

METHODS

27 pts (19 males, 61 +/- 10 years), NYHA functional class IV, with dilated cardiomyopathy (13 idiopathic, 10 ischemic, 4 hypertensive), 17 with exclusion criteria for heart transplantation, were included. Echocardiographic left ventricular end-diastolic dimension and ejection fraction were 68 +/- 8 mm and 20 +/- 9%, respectively. Initial (i) serum sodium (Na+) was 136 +/- 5 mEq/l and i serum creatinine (Cr) was 1.4 +/- 0.8 mg/dl. Baseline, at referral, hemodynamics: SAP = 125 +/- 23, PWP = 23 +/- 6, RAP = 12 +/- 6, cardiac index (CI) = 1.9 +/- 0.5 l/min/m2, SVR = 2193 +/- 670. Using bedside right heart catheterization (Swan-Ganz catheter) we set out to achieve the above hemodynamic goals.

RESULTS

1) v and d used: sodium nitroprusside--cumulative dose = 196 +/- 121 mg, captopril--daily dose (dd) = 157 +/- 95 mg, isosorbide dinitrate--dd = 91 +/- 57 mg, hydralazine--dd = 95 +/- 67 mg, and furosemide--dd = 105 +/- 70 mg; 2) final (f) hemodynamic parameters on tailored therapy: SAP = 109 +/- 20*, PWP = 12 +/- 3*, RAP = 4 +/- 3*, CI = 2.5 +/- 0.6*, SVR = 1317 +/- 340* (*: p < 0.001 vs baseline); 3) duration of invasive monitoring was 3.0 +/- 1.9 days; 4) f Na+ = 134 +/- 5, and f Cr = 1.5 +/- 0.8 (NS vs i); 5) there was one (4%) in-hospital death; functional class of discharged pts: III--4 pts, II--18 pts, I--4 pts; 6) nine pts (35%) died after discharge--three due to refractory heart failure and six (including two potential heart transplant candidates) had sudden death; 7) actuarial survival (Kaplan-Meyer method): at 6 months (m)--80%, 12 m--71%, 18 m--64%, 24 m--55%; 8) after a mean follow-up of 18 +/- 8 m, functional class in survivors was: NYHA IV--2 pts, III--4 pts, II--8 pts, and I--3 pts.

CONCLUSIONS

Therapy tailored to hemodynamic goals is a valid approach for pts with advanced heart failure, showing good hemodynamic and functional short-term results, and reasonable survival at two years. The significant incidence of sudden death demands strategies for risk stratification and a search for prophylactic measures in this population.

Iron therapy for improving psychomotor development and cognitive function in children under the age of three with iron deficiency anaemia

BACKGROUND

Iron deficiency and iron deficiency anaemia (IDA) are common in young children. It has been suggested that the lack of iron may have important effects on children's psychomotor development and cognitive function.

OBJECTIVES

To determine the effects of iron therapy on psychomotor development and cognitive function in iron deficient children less than 3 years of age.

SEARCH STRATEGY

The following databases were searched: COCHRANE LIBRARY (2000 ISSUE 4) MEDLINE (1966-August 2000) EMBASE (1980-August 2000) Latin American Database (LILACS) PsycLIT Journal articles (1974-August 2000) PsycLIT Chapters and Books (1987-August 2000) The references of identified trials and of important review articles were scrutinised. Citation searches on trials from the primary search were performed within the Science Citation Index. Key authors were contacted.

SELECTION CRITERIA

Studies were included if children less than 3 years of age with evidence of iron deficiency anaemia were randomly allocated to iron or iron and vitamin C versus a placebo or vitamin C alone and assessment of developmental status or cognitive function was carried out using standardised tests by observers blind to treatment allocation.

DATA COLLECTION AND ANALYSIS

Abstracts and titles of studies identified on searches of electronic databases were read to determine whether they might meet the inclusion criteria. Full copies of those possibly meeting these criteria from electronic or other searches were assessed by two independent reviewers. Differences of opinion about suitability for inclusion were resolved by discussion. Data were analysed separately depending on whether participants had iron assessments were performed within one month of beginning iron therapy or later.

MAIN RESULTS

Five trials, including 180 children with IDA, examined the effects of iron therapy on measures of psychomotor development between 5 and 11 days of commencement of therapy. Data from four trials could be pooled. The pooled difference in pre to post treatment change in Bayley Scale PDI between iron treated and placebo groups was -3.2 (95%CI -7.24, 0.85) and in Bayley Scale MDI, 0.55 (95% CI -2.84, 1.75). Two studies, including 160 randomised children with IDA, examined the effects of iron therapy on measures of psychomotor development more than 30 days after commencement of therapy. Aukett et al reported the mean number of skills gained after two months of iron therapy, using the Denver test. The intervention group gained 0.8 (95% CI -0.18, 1.78) more skills on average than the control group. Idjrandinata et al reported that the difference in pre to post treatment change in Bayley Scale PDI between iron treated and placebo groups after 4 months was 18.40 (95%CI 10.16, 26.64) and in Bayley Scale MDI, 18.80 (95% CI 10.19, 27.41).

REVIEWER'S CONCLUSIONS

There is no convincing evidence that iron treatment of young children with IDA has an effect on psychomotor development discernable within 5-11 days. The effect of longer term treatment remains unclear but the data would be compatible with clinically significant benefit. There is urgent need for further randomised controlled trials with long term follow up.

Non-invasive monitoring of pulmonary capillary wedge pressure in heart failure

OBJECTIVE

To evaluate the usefulness of pulsed Doppler (PD) mitral flow E wave deceleration time (EDcT) to detect and quantify changes of pulmonary capillary wedge pressure (PCWP) in patients (pt) with dilated chronic heart failure (CHF) submitted to tailored therapy.

METHODS

In 14 pt with dilated cardiomyopathy (DCM) (59.4+/-10.0 years, 11 males, sinus rhythm), admitted to the ICU because of worsening CHF, serial simultaneous hemodynamic and echocardiographic studies were performed (3-5/pt; overall 49 evaluations). PD mitral flow register was used to measure EDcT and correlated with PCWP at each study.

RESULTS

PCWP ranged from 36 to 3 mmHg (17.6+/-8.8) and EDcT from 271 to 52 ms (104.9+/-42.4). The correlation between EDcT and PCWP was -0.65 (PCWP=31.7-0.134EDcT). Using this equation to calculate PCWP, individual absolute values difference (identity error - IE) was 5.6+/-3.5 mmHg (0.4-14.6). In 29 cases (59.2%) IE was >5 mmHg, defined as major error. Considering EDcT percent change (delta%EDcT) and PCWP variation (deltaPCWP) in serial evaluations, we found a correlation of -0.87 (deltaPCWP=-2.83-0.19 delta%EDcT). Using this equation, the IE was 2.3+/-1.6 mmHg (0-5.2) and there were only two (6%) major errors (P<0.0001).

CONCLUSIONS

In pt with DCM and advanced CHF, EDcT shows a reasonable correlation with PCWP, but when it is used to calculate PCWP the IE to hemodynamic values is often large. However, our results with EDcT percent change in serial evaluations using a first simultaneous invasive determination, suggest that this technique is reliable for monitoring PCWP and can be particularly useful for pt submitted to tailored therapy.

Exploring ADHD age-of-onset criterion in Brazilian adolescents

OBJECTIVE

To explore age-of-onset criterion for the diagnosis of attention-deficit hyperactivity disorder (ADHD) in a school sample of young Brazilian adolescents.

METHODS

191 students aged 12 to 14 years were evaluated using DSM-IV ADHD criteria, measures of ADHD symptoms and global impairment.

RESULTS

Both adolescents with ADHD (n = 30) and adolescents who fulfilled all DSM-IV ADHD criteria, except age of onset of impairment criterion (ADHD w/o age-of-onset, n = 27) had significantly higher scores on Attention Problems, Delinquent and Aggressive Behavior scales of the Child Behavior Checklist (CBCL) and lower scores on the Child Global Assessment scale (CGAS) than non-ADHD adolescents (n = 134). Adolescents with ADHD and youths with ADHD w/o age-of-onset did not differ significantly in any measure assessed.

CONCLUSION

These results concur with recent literature proposing revision of the age-of-onset criterion for the diagnosis of ADHD.

New criteria for the diagnosis and treatment of atrioventricular node reentrant tachycardia

The authors describe a new elecrocardiographic criterion to diagnose atrioventricular node reentrant tachycardia, review the electrocardiographic and electrophysiological diagnosis of this tachyarrhythmia and analyse the results of catheter ablation of fast versus slow pathway, selecting the fast pathway whenever the induction of atrioventricular node reentrant tachycardia is performed only after pharmacological maneuvers. The high specificity for atrioventricular node reentrant tachycardia of the criterion characterized by the absence of ST-segment depression found in left precordial leads from V4 to V6 suggests the need to include it in electrocardiographic algorithms for the differential diagnosis of tachycardias with a narrow QRS complex. The high primary and final success rates of catheter ablation obtained after a therapy stratification based on induction criteria, emphasize the use of the fast pathway ablation as a first option in selected cases and for the treatment of recurrences.

Density mismatch in thin diblock copolymer films

Thin films of diblock copolymer subject to gravitational field are simulated by means of a cell dynamical system model. The difference in density of the two sides of the molecule and the presence of the field causes the formation of lamellar patterns with orientation parallel to the confining walls even when they are neutral. The concentration profile of those films is analyzed in the weak segregation regime and a functional form for the profile is proposed.

Cardiac output quantification by Doppler echocardiography in intensive care--limitations and validation

Cardiac output (CO) quantification is primordial to the evaluation of patients with heart failure who are on tailored therapy and under invasive hemodynamic monitoring. Doppler echocardiography can be used to access CO noninvasively, but the concordance between its results and those obtained by invasive methods in paired measurements is still controversial. To our knowledge, no previous studies have assessed the clinical relevance of Doppler echocardiography for CO serial evaluation in patients submitted to tailored therapy.

AIM

To evaluate the usefulness of echo-Doppler in the assessment of CO and quantification of changes in CO, compared to thermodilution, in patients with advanced heart failure under hemodynamic monitoring to guide tailored therapy.

METHODS

In 20 patients (14 male, 62 +/- 14 years old, all in sinus rhythm), with dilated cardiomyopathy and NYHA IV, admitted to the intensive care unit (ICU), CO was simultaneously determined by Doppler echocardiography (dpCO) and thermodilution (tdCO) in three serial evaluations (overall 60). The dpCO was calculated by multiplying the aortic orifice area by the velocity-time integral of aortic continuous wave Doppler flow and by the heart rate. A difference between tdCO and dpCO of more than 20% was considered a major error.

RESULTS

In the overall evaluations, dpCO systematically overestimates tdCO (p = 0.026). The correlation between tdCO and dpCO was 0.81, the mean difference between measurements was 0.40 +/- 0.61 l/min (mean -2SD = -1.62 mean +2SD = 0.81) and 19 (32%) major errors occurred. No significant difference was found between CO percentual variation values assessed by both methods, with a stronger correlation (r = 0.92-p = 0.014) compared to that found for absolute values. On using the dpCO/tdCO ratio in the first evaluation to correct subsequent dpCO, the correlation was fairly good (r = 0.96-p = 0.0002 versus corrected dpCO). The mean difference between paired measurements was significantly lower (0.12 +/- 0.28 l/min-mean 2SD = -0.44 mean +2SD = 0.67), and there were no errors.

CONCLUSIONS

CO estimated by Doppler echocardiography has a good correlation with thermodilution although with a weak concordance between paired results in patients with dilated cardiomyopathy and advanced heart failure admitted to the ICU for tailored therapy. Our results with dpCO percentual change in repeated evaluations and with corrected dpCO value after a single simultaneous invasive determination suggest that Doppler echocardiography is a valid method for clinical purposes, allowing us to propose a reduction in the time period of invasive hemodynamic monitoring.

[Comparative study of Toronto SPV prosthesis and bileaflet mechanical aortic prosthesis with 2D-Doppler echocardiography]

AIM

The aim of this study was to make a noninvasive comparison, by means of Doppler echocardiography, of the hemodynamic performance of biological stentless xenografts and mechanical bileaflet (MB) prostheses (P) in aortic position.

METHODS

We studied 20 patients (pts) with normofunctional (nf) aortic Toronto (T) Stentless Porcine valves (SPV)--Group I--8 males, aged 69 +/- 12 years, 32 +/- 9 months after surgery, and 30 pts with nf MB aortic P (Carbomedics or St. Jude Medical)--Group II--17 males (p = NS vs G I), aged 61 +/- 12 years (p < 0.01 vs G I), 30 +/- 12 months after implantation (p = NS vs G I). Both groups were comparable with regard to body surface area and surgical indication. P diameters ranged from 21 to 25 mm (G I: 22.9 +/- 1.7; G II: 22.8 +/- 1.7 - p = NS), the number of pts with the same P diameter in each group being similar. We analysed, at rest: aortic orifice diameter (AoOd - cm), maximal (GMax) and mean (GMean) transprosthesic pressure gradients, P functional area (PFA) and P resistance (PRes). Gradients (mm Hg) were calculated by means of the Bernoulli equation, PFA (cm2) by means of the continuity equation and PRes (dynes.s.cm-5) as 1333 x Gmean x SEP/SV (SEP = systolic ejection period; SV = stroke volume).

RESULTS

AoOd (G I vs G II): P 21--1.78 +/- 0.04 vs 2.00 +/- 0.10 (p < 0.001); P 23--1.91 +/- 0.10 vs 2.19 +/- 0.10 (p = 0.01); P 25--2.22 +/- 0.24 vs 2.29 +/- 0.19 (NS). Doppler parameters: [table: see text]

CONCLUSIONS

P T SPV show better hemodynamic performance when compared to P MB with the same diameter, in aortic position. In addition, our results suggest that P T SPV allow the use of larger valve sizes for the same aortic orifice diameter.

[The metabolic-chronotropic relation in patients with heart failure--a correlation with functional capacity]

Previous studies on chronotropic incompetence (CI) in patients with congestive heart failure (CHF) have defined it as the inability to achieve > 80% of age predicted maximum heart rate (HR) (adequacy of HR response to submaximal exercise levels not being considered). The metabolic chronotropic relation (MCR) concept proposed by Wilkoff allows the assessment of the entire chronotropic function. The value of such an approach for the evaluation of CI in patients with CHF, and its relation to exercise capacity, is unclear at present.

METHODS

We imposed maximal symptom-limited treadmill exercise testing while measuring breath-by-breath oxygen consumption, using CAEP protocol, in 25 patients (19 men), 49 +/- 10 years, all in sinus rhythm, with CHF secondary to dilated cardiomyopathy (17) or ischemic heart disease (8), NYHA class II-III. Anaerobic threshold (AT) was attained by all. No exercise was terminated due to arrhythmia or ischemia. MCR was calculated as the slope of the relation between the percentages of HR and metabolic reserves achieved at the end of each exercise stage. Using 2.0 standard deviations below the mean level of MCR in healthy controls, we defined an MCR value < 0.84 as abnormal. The parameters analysed were: age, drug therapy, fractional shortening (FS-%), resting HR (RHR-bpm), exercise duration (DUR-min), peak HR (HRp), peak oxygen consumption (VO2p-ml/kg/min), percentages of predicted maximal HR (% PMHR) and VO2 (% PMVO2), peak ventilatory equivalent for CO2 (VE/VCO2-L/min), time to AT (T-AT), and VO2 at AT (VO2-AT).

RESULTS

MCR was normal (1.01 +/- 0.18-0.86 to 1.19) in 10 patients--Group I, and abnormal (0.66 +/- 0.13-0.42 to 0.81) in 15 (60%) patients--Group II. A similar proportion of patients in both groups were taking ACE inhibitors, digoxin and amiodarone. [table: see text] CI defined as an inability to achieve a % PMHR > 80% occurred only in 6 (24%) patients, all in Group 2 (p = 0.022 versus abnormal MCR).

CONCLUSIONS

In CHF patients, CI assessed as an abnormal MCR is frequent, and relates to an impaired exercise capacity.

Molecular analyses of the vasopressin type 2 receptor and aquaporin-2 genes in Brazilian kindreds with nephrogenic diabetes insipidus

Nephrogenic diabetes insipidus (NDI) is associated with germline mutations in two genes: vasopressin receptor type 2 (V2(R)) in X-linked NDI, and the water channel aquaporin-2, in autosomal-recessive disease. Genetic heterogeneity is further emphasized by reports of phenotypically abnormal individuals with normal structural genes. We analyzed both genes in five Brazilian families and the aquaporin-2 gene in two Swedish families with clinical and laboratory diagnosis of NDI, by a combination of denaturing gradient gel electrophoresis (DGGE) and direct DNA sequencing. A novel polymorphism in the aquaporin-2 gene (S167S), but no disease-associated mutations in any tested individual from all seven families, was detected. In two Brazilian families, frameshift mutations were detected in the V2(R) gene: one leading to a premature stop after codon 36 and the other to a longer peptide (462 aa instead of the 373 aa wild-type protein). In two other Brazilian families, probable disease-associated missense mutations were detected: an alanine to proline at codon 163 (A163P) and an asparagine to aspartic acid at codon 85 (D85N). In one Brazilian family, both genes were structurally normal and the aquaporin-2 gene was also normal in the two Swedish kindreds. This report further extends the mutational spectrum of NDI and suggests that there are other mutational or epigenetic events inactivating the two known genes or even novel genes that underlie NDI.

[Atrial fibrillation in Wolff-Parkinson-White syndrome]

The authors describe the main etiopathogenic factors and clinical importance of atrial fibrillation and analyse the results of catheter ablation of atrioventricular accessory pathways in Wolff-Parkinson-White syndrome. Atrial vulnerability is the principal mechanism and radiofrequency catheter ablation of atrioventricular accessory pathways seems to be useless to prevent atrial fibrillation.

ADHD in a school sample of Brazilian adolescents: a study of prevalence, comorbid conditions, and impairments

OBJECTIVE

To evaluate the prevalence, comorbid conditions, and impairments of attention-deficit/hyperactivity disorder (ADHD) among young adolescents in Porto Alegre, Brazil.

METHOD

1,013 students aged 12 to 14 years were evaluated at 64 state schools, using a screening instrument based on the 18 DSM-IV ADHD symptoms. All positive screened students (n = 99) and a random subset of negative screened subjects (n = 92) had a psychiatric evaluation carried out within a hospital setting or at home.

RESULTS

The prevalence of ADHD was estimated to be 5.8% (95% confidence interval = 3.2-10.6), and the comorbidity with other disruptive behavior disorders was high (47.8%). Youths with ADHD (n = 23) had significantly higher rates of school repetitions, suspensions, and expulsions (p < .01) than controls (n = 168). No association was identified between ADHD and alcohol, marijuana, and inhalant use.

CONCLUSION

The results extend to adolescents well-documented findings in children, indicating that ADHD is quite prevalent in early adolescence and affected youths are at high risk for impairment and dysfunction in multiple domains.

[Time integral of oxygen pulse for exercise submaximal levels in patients with heart insufficiency--correlation with maximal oxygen consumption]

Maximal oxygen consumption (VO2max) has an important prognostic value in patients with congestive heart failure (CHF). However, it requires a maximal exercise test, not often available for these patients. To overcome this limitation, we examined whether a simple time integral of oxygen pulse (OP) to submaximal exercise levels correlates with VO2max.

METHODS

We performed a maximal symptom-limited treadmill exercise test, while measuring breath-by-breath oxygen consumption, using the CAEP protocol, in 24 patients with CHF (51 +/- 11 years, 18 males, sinus rhythm). No exercise was terminated due to ischemia or arrhythmias. All patients attained anaerobic threshold. Besides standard parameters, OP (ml) and time integral of OP (OPTI) were calculated at 2 minutes (OP-2 min and OPTI-2 min) and at 4 minutes (OP-4 min and OPTI-4 min) of exercise. Patients were divided in two groups according to VO2max: group I--VO2max > or = 16 ml/kg/min (14 patients) and group II--VO2max < 16 (10 patients).

RESULTS

Age, sex, body surface and CHF etiology were similar in both groups. Exercise duration, maximal OP, time to anaerobic there shold, VO2 and OP at anaerobic there shold were higher in group I (p < 0.05). Comparing group I vs group II--OP-2 min: 6.2 +/- 1.5 vs 5.0 +/- 1.2 ml (p = 0.026); OP-4 min: 7.6 +/- 1.9 vs 5.4 +/- 1.2 (p = 0.001); OPTI-2 min: 3.1 +/- 1.1 vs 2.2 +/- 0.9 (p = 0.021) and OPTI-4 min: 15.2 +/- 4.4 vs 9.3 +/- 3.1 (p = 0.0007). The best correlation with VO2max was obtained for OPTI-4 min (r = 0.696). An OPTI-4 min value > or = 10 occurred in 13 patients of group I and in two patients of group II (p = 0.00013), with a predictive value of 87% for VO2max > 16 (sensitivity = 93%, specificity = 80%)--kappa index = 0.739.

CONCLUSIONS

OPTI-4 min can be a useful tool for assessing cardiocirculatory functional status in patients with CHF and unable to perform a maximal exercise test.

Cerebral astrocyte response to micromachined silicon implants

The treatment of neurologic disorders and the restoration of lost function due to trauma by neuroprosthetic devices has been pursued for over 20 years. The methodology for fabricating miniature devices with sophisticated electronic functions to interface with nervous system tissue is available, having been well established by the integrated circuit industry. Unfortunately, the effectiveness of these devices is severely limited by the tissue reaction to the insertion and continuous presence of the implant, a foreign object. This study was designed to document the response of reactive astrocytes in the hope that this information will be useful in specifying new fabrication technologies and devices capable of prolonged functioning in the brain. Model probes fabricated from single crystal silicon wafers were implanted into the cerebral cortices of rats. The probes had a 1 x 1-mm tab, for handling, and a 2-mm-long shaft with a trapezoidal cross-section (200-microm base, 60microm width at the top, and 130 microm height). The tissue response was studied by light and scanning electron microscopy at postinsertion times ranging from 2 to 12 weeks. A continuous sheath of cells was found to surround the insertion site in all tissue studied and was well developed but loosely organized at 2 weeks. By 6 and 12 weeks, the sheath was highly compacted and continuous, isolating the probe from the brain. At 2 and 4 weeks, the sheath was disrupted when the probe was removed from the fixed tissue, indicating that cells attached more strongly to the surface of the probe than to the nearby tissue. The later times showed much less disruption. Scanning electron microscopy of the probes showed adherent cells or cell fragments at all time points. Thus, as the sheath became compact, the cells on the probe and the cells in the sheath had decreased adhesion to each other. Immunocytochemistry demonstrated that the sheath was labeled with antibodies to glial fibrillary acidic protein (GFAP), an indicator for reactive gliosis. The tissue surrounding the insertion site showed an increased number of GFAP-positive cells which tended to return to control levels as a function of time after probe insertion. It was concluded that reactive gliosis is an important part of the process forming the cellular sheath. Further, the continuous presence of the probe appears to result in a sustained response that produces and maintains a compact sheath, at least partially composed of reactive glia, which isolates the probe from the brain.

[Antitachycardia pacing in patients with left ventricular dysfunction and hemodynamically unstable arrhythmias]

The use of antitachycardia pacing (ATP) has shown itself to be an effective therapeutic option in the treatment of ventricular tachycardia (VT) in carriers of implantable cardioverter defibrillators (ICD).

OBJECTIVE

To assess the safety and efficacy of ATP in ICD carriers with ischemic cardiopathy and systolic dysfunction of the left ventricle (LV) presenting VT badly tolerated hemodynamically.

METHODS

We studied five patients (four male and one female), survivors of acute myocardial infarction, mean age 56.4 +/- 15.7 years and an ejection fraction < 35%, submitted to ICD implantation by VT inducible in the electrophysiological study (EPS) and refractory to pharmacologic therapy. In three cases the arrhythmia was syncopal and in two the patients felt palpitations and dizziness (systolic blood pressure < 90 mmHg during VT). The ICDs were implanted between March 1996 and October 1997 by transvenous approach in pectoral position. ATP was used as an initial therapeutic alternative (VT zone with a detection frequency of 160-220/min) according to an empirical programme (n = 3) or, whenever feasible, in accordance with the type of VT interruption during EPS (n = 2). During the follow-up of 11 +/- 6 months (2-18), a periodic assessment of the symptomatology and a detailed analysis of episodes of ventricular arrhythmia detected by ICD were made.

RESULTS

Two hundred and fourteen episodes of VT were recorded with a post detection duration of > 2.5 sec treated by ICD. The ATP rate of efficacy was 93%. In 3% of the episodes the ATP did not alter VT; in 2% the rate of VT increased (reduction of the VT cycle > 20%) and in 2% therapeutic exhaustion was observed (after the application of ATP and the maximum number of shocks per episode). In 14 episodes with ATP inefficiency, two syncopes occurred (1% of the total number of episodes treated).

CONCLUSION

In this study antitachycardia pacing has proven to be a therapeutic option with high rates of efficacy and safety despite its use in survivors of myocardial infarction with moderate to severe compromise of systolic function of the left ventricle and ventricular arrhythmias with hemodynamic instability.

[The semiquantitative evaluation of systemic vascular resistances in heart failure via an analysis of Doppler aortic flow]

In patients with advanced heart failure (HF) submitted to tailored therapy, monitoring of systemic vascular resistance (SVR) is essential to establish an adequate hemodynamic response, being one of the end-points to achieve SVR < 18 Wood U (WU).

PURPOSE

To correlate SVR value with parameters derived from the analysis of echo-Doppler aortic flow in patients with HF on tailored therapy, in order to allow a non-invasive semiquantitative evaluation of this hemodynamic end-point.

METHODS

In 13 patients with dilated cardiomyopathy (eight idiopathic, five ischemic) and advanced HF (mean age 60 +/- 10 years, 10 male, all in sinus rhythm, NYHA class IV), admitted in the ICU and submitted to tailored therapy, serial simultaneous hemodynamic and echocardiographic studies were performed (2 to 5 per patient, overall 43 evaluations). The following parameters derived from the analysis of continuous wave aortic Doppler flow were analysed: peak velocity, acceleration, deacceleration and ejection times, systolic time intervals ratio, mean acceleration, mean deacceleration, acceleration, deacceleration and overall systolic flow velocity time integrals.

RESULTS

SVR ranged from 10.4 to 41.9 WU (mean = 21.7, SD = 6.9). A significant correlation was found only with mean deacceleration (MnDc)-r = -0.60. MnDc ranged from 362 to 1162 cm/s2 (mean = 667, SD = 188) and proved to be independent from heart rate, systolic, diastolic and mean blood pressure, capillary wedge pressure, cardiac output, cardiac index and ejection volume. MnDc < 700 cm.s2 occurred in 25/28 evaluations with SVR > 18 WU and only in 3/15 evaluations with SVR < 18 WU-p = 0.00003. A MnDc value < 700 cm.s2 showed sensitivity = 89%, specificity = 80%, and predictive value = 89% for SVR > 18 WU (Kappa index = 0.693).

CONCLUSION

Mean deacceleration of aortic continuous wave flow is reliable for semiquantitative evaluation of systemic vascular resistance and can be particularly useful for patients with advanced heart failure submitted to tailored therapy.

[The influence of therapy (sympathomimetic amines versus vasodilators) in the indexes of ejection fraction derived from an analysis of Doppler aortic flow]

PURPOSE

To assess the influence of inotropic IV therapy--dobutamine and/or dopamine--versus vasodilator therapy--nitroprusside, captopril or hydralazine--in aortic flow ejection phase indexes obtained by pulsed Doppler echocardiography.

METHODS

In 17 patients admitted to the ICU (11 males, 62 +/- 14 years, 9 with ischemic cardiomyopathy and 8 with dilated cardiomyopathy, all in sinus rhythm), with congestive heart failure, and submitted to tailored therapy, 53 serial pulsed Doppler and hemodynamic evaluations were made as the therapy changed the hemodynamic and clinical status. Considering serial consecutive evaluations, a hemodynamic improvement was obtained only with inotropics in 13 (group A), and with vasodilators in only 15 (group B). The following ejection phase indexes were calculated from Doppler registers: average acceleration (AvAc) and ejection force (EFor), calculated according to the formula: Efor = 1.06 x Aortic Orifice Area x AvAc x Acceleration Velocity Time Integral.

RESULTS

Arterial blood pressure increased in gr A (76.2 +/- 14.1 to 81.4 +/- 14.8 mm Hg, p < 0.05) and decreased in gr B (85.1 +/- 12.6 to 76.2 +/- 9.7 mm Hg (p < 0.05). In both groups there was a significant (p < 0.05) increase in cardiac output (CO)-from 3.9 +/- 1.1 to 4.9 +/- 1.4 L/min in group A, and from 3.9 +/- 1.2 to 4.4 +/- 1.2 L/min in group B. CO increased 18.7% in group A and 13.8% in group B (NS). There was a decrease in pulmonary capillary wedge pressure (PCWP) from 19.5 +/- 6.0 to 15.1 +/- 5.8 mm Hg in group A (p < 0.05), and from (16.9 +/- 5.7 to 12.1 +/- 4.6 mm Hg in group B (p < 0.05). PCWP decreased 19.7% in group A and 27.8% in group B (NS). Systemic vascular resistance (SVR) changed from 18.2 +/- 7.0 to 16.2 +/- 7.1 Wood U in group A (p < 0.05), and from 22.3 +/- 9.3 to 17.7 +/- 5.7 Wood U in group B (p < 0.05). In group A, AvAc increased-from 1347 +/- 611 cm.s-2 (p < 0.05), as did Efor-from 15.4 +/- 10.7 to 20.2 +/- 11.0 g.cm,s-2 (p < 0.05), whereas in group B there was no significant change in either AvAc-from 1337 +/- 284 to 1277 +/- 256 cm.s-2, or Efor-from 22.7 +/- 17.0 to 23.8 +/- 15.0 g.cm.s-2.

CONCLUSIONS

Vasodilator therapy, although inducing hemodynamic changes similar to inotropics, does not alter the ejection phase indexes. Therefore, AvAc and Efor, in spite of being calculated from the aortic flow, are independent of the changes in PCWP and SVR and seem to reflect changes in inotropism in the clinical setting.

Determination of some physicochemical parameters of microcystins (cyanobacterial toxins) and trace level analysis in environmental samples using liquid chromatography

Some physicochemical parameters of three microcystin standards, known to be potent hepatotoxins produced by cyanobacteria, were determined using well defined chromatographic measurements. The logarithm of their retention factor on octadecylsilica (ODS) with water as the eluent, which is an estimation of the hydrophobicity of a molecule, was assessed at pH 7 at 3.9, 4.2 and 4.4 for microcystins-YR, -LR and -RR, respectively. Though being rather hydrophobic, microcystins also possess polar functions, namely carboxylic acids, amino and amido groups. The ionization of carboxylic groups occurs at pH values of 3.3-3.4. In environmental waters, microcystins are neutral or anionic. They are readily soluble in water, the solubility of microcystin-LR being higher than 1 g/l. Owing to their hydrophobicity and their polar functions, microcystins remain in the aqueous phase rather than being adsorbed on sediments or on suspended particulate matter. In a river water spiked with microcystins at 5 micrograms/l, only 10% was adsorbed on particles and 7% on the sandy sediment after three days. A method using solid-phase extraction on ODS followed by high-performance--or micro--liquid chromatography was optimized to detect microcystins at trace level in water. A clean-up was introduced to eliminate part of the interfering compounds coextracted during the sample percolation. Good recoveries (75-80%) were obtained. The method was linear, reproducible (with relative standard deviations ranging from 5 to 8%) and enabled the determination of microcystins at levels as low as 30 ng/l in drinking water and 100-200 ng/l in surface waters. The production of toxins by two strains of cyanobacteria was evaluated. Variations in the microcystin-LR content in the cells and in the medium of Microcystis aeruginosa PCC7806 were recorded over a five-week period. Toxin production was not correlated to the biomass but depended on the growth stage and was maximal at the end of the exponential growth phase. The release of toxin in water occurred essentially in old cultures where microcystin-LR was determined at concentrations of 170 and 280 micrograms/l in the media of M. aeruginosa PCC7806 and M. aeruginosa PCC7813, respectively. Other microcystins are likely to be synthesized by these strains. But owing to the lack of standards, mass spectrometric detection is required for further identification. This study points out the need of having other standards for water quality monitoring.

Partial dominance of a keratin 14 mutation in epidermolysis bullosa simplex--increased severity of disease in a homozygote

Epidermolysis bullosa simplex is a disease in which keratin gene mutations cause the production of defective intermediate filaments, which leads in turn to epidermal basal cell fragility and blistering. The inheritance in nearly all kindreds is autosomal dominant, most kindreds have missense mutations, and the encoded proteins appear to exert a dominant negative function. One previously reported patient with generalized blistering had a fully dominant mutation of keratin 5; in that kindred a homozygote was affected no more severely than the heterozygotes. By contrast we report here a keratin 14 mutation that causes blistering limited to the hands and feet in heterozygotes, but homozygotes have more severe, widespread blistering of the skin and mucous membranes. Thus keratin gene mutations may be not only fully recessive or fully dominant but also partially dominant as well.

Maternity blues in Brazilian women

In this prospective study, a sample of 86 postpartum women was compared with a sample of 75 women from a random period of 8 consecutive days out of puerperium. Symptoms were evaluated each day using the Blues Questionnaire. Postpartum women and women out of puerperium showed a different distribution of percentile scores on the scale on the third, fourth and fifth days. The postpartum symptom peak occurred on the fifth day. Symptoms more significantly associated with the third, fourth and fifth postpartum days were overemotionalism and oversensitivity. It is concluded that maternity blues in Brazilian women appear to be characterized by maternal mental state alterations occurring on the third, fourth and fifth days postpartum. MB seems to be better defined as an emotional oversensitivity syndrome of cross-cultural dimension than as depression.