Experimental evidence of coupling effects in a twin-ridge laser

We present for the first time (to our knowledge) experimental data on the intrinsic relaxation oscillation frequency in a twin-ridge laser array. We present a detailed analysis of the frequency response of the device, both under single-ridge operation as well as in twin ridge. We demonstrate the strong influence that the injection current on one ridge has over the relaxation oscillation frequency of the other. Using previously defined dependencies for the twin ridge, we link the imaginary part of the coupling constant to the observed variations in the relaxation oscillation frequency, proposing a procedure to determine a parameter that so far has been used as a free adjustment value.

2D versus 3D in the kinematic analysis of the horse at the trot

The handled trot of three Lusitano Purebred stallions was analyzed by using 2D and 3D kinematical analysis methods. Using the same capture and analysis system, 2D and 3D data of some linear (stride length, maximal height of the hoof trajectories) and angular (angular range of motion, inclination of bone segments) variables were obtained. A paired Student T-test was performed in order to detect statistically significant differences between data resulting from the two methodologies With respect to the angular variables, there were significant differences in scapula inclination, shoulder angle, cannon inclination and protraction-retraction angle in the forelimb variables, but none of them were statistically different in the hind limb. Differences between the two methods were found in most of the linear variables analyzed.

Three-dimensional inversion rendering in the first- and early second-trimester fetal brain: its use in holoprosencephaly

OBJECTIVES

To explore the feasibility and added value of three-dimensional (3D) inversion rendering of the developing embryonic/fetal ventricular system, and to apply this display technique to enhance the sonographic examination of holoprosencephaly.

METHODS

3D volumes of the embryonic/fetal brain were acquired from four normal fetuses at 8-11 postmenstrual weeks, and four fetuses diagnosed with holoprosencephaly between 9 and 14 postmenstrual weeks. The volumes were then analyzed offline to obtain inversion rendered 3D shapes of the ventricular systems.

RESULTS

All inversion rendering displays were successful and provided the opportunity to study normal as well as pathological aspects of the early fetal brain.

CONCLUSIONS

Inversion rendering of early fetal brain ventricles is feasible and should be attempted if additional information about the early normal or pathological fetal brain is needed. It may have scientific value in embryologic or genetic studies.

Comet assay to determine DNA damage induced by food deprivation in rats

The aim of this work was to evaluate, by comet assay, the possible inducing of DNA lesions in peripheral blood mononuclear cells of rats subjected to acute or chronic food deprivation. Wistar male rats were subjected to 72 h of partial (50%), or total acute food deprivation, and then allowed to recover for different time periods (24, 48 and 72 h). In other experiments, comet scores were determined in peripheral blood mononuclear cells of rats subjected to chronic food deprivation (25% and 50%) for 50 days. Blood aliquots were obtained before, during and after food deprivation. Comet assay was carried out, the comet units photographed and scored (class 0 up to 3). Acute and chronic food-deprived rats presented peripheral blood mononuclear cells with DNA lesions (comet classes 1, 2 and 3) and a significant increase (p<0.05) in the number of comet units compared with its basal level. The increase was proportional to acute food deprivation time, but after being taken off, it progressively returned to basal level after 48 h (partial group) or 72 h (total group). Chronic food-deprived rats presented a progressive increase of comet score up to 5 days, and a decrease thereafter to reach a basal level. Possible mechanisms of DNA lesions are discussed.

Association of physical fitness and body mass index in youth

AIM

The aim of this study was to establish physical fitness (PF) levels in a school population of 11-18-year-old students and analyse differences according to body mass index (BMI) status in overweight

METHODS

This is a cross-sectional study. The sample comprises 636 children and adolescents (mean age of 14.5+/-1.5 years), 288 boys (45.3%) and girls 347 (54.7%). Six tests from Fitness-gram battery were used as an objective measure of physical fitness. Overweight/ Obesity status was determined using age and sex adjusted cut-off points.

RESULTS

Both girls and boys with obesity performed a significantly reduced number of tests in healthy fitness zone suggesting a decrease of performances in strength and cardiovascular fitness, from normal weight status to overweight and from overweight to obesity. Boys and girls with obesity are likely to be Under HFZ than normal weight.

CONCLUSION

The results suggest that obese and overweight children have low PF level compared to normal weight peers. A large number of children with normal weight were identified as well as unfit. These data also showed that a low BMI level would significantly improve some PF component.

CIRURGIA TORÁCICA VIDEO-ASSISTIDA (CTVA) NA CORREÇÃO DE DUCTO ARTERIOSO PATENTE. ESTUDO EXPERIMENTAL EM CÃES

Foram utilizados 14 cães adultos sem raça definida, sendo 8 machos e 6 fêmeas, cujos pesosvariaram de 10 a 20 kg, provenientes do Biotério Central da UFSM, objetivando-se estudar técnica de correçãode ducto arterioso patente (DAP) por cirurgia torácica vídeo-assistida (CTVA). Concluiu-se que: os três portaisde trabalho e a ótica foram suficientes e se localizaram adequadamente para a correção do DAP; materiais decirurgia vascular podem ser empregados para a realização desta técnica; o posicionamento da equipe cirúrgica,do paciente, dos equipamentos e dos instrumentais foi adequado; o nó de Roeder mostrou-se efetivo; oprocedimento proposto é viável no período de até cinco dias de pós-operatório; esta técnica se mostrou-seefetiva e pode ser empregada na correção de DAP e para o treinamento de cirurgiões na correção do DAPcongênito. Este estudo foi aprovado pela Comissão de Ética da UFSM sob número 012/2005. Todos os animaisforam encaminhados para adoção.

Anatomic segmentectomy for stage I non-small cell lung cancer: Comparison of outcomes with the VATS versus open approach

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Background: Anatomic segmentectomy for early-stage NSCLC has been proposed as a means of achieving a complete resection in high-risk patients with poor lung function, who might not otherwise tolerate conventional lobectomy. Historically, anatomic segmentectomy has been associated with increased recurrence rates and postoperative air leaks. In the current study, we present our experience with VATS versus open segmentectomy for stage I NSCLC. Methods: A total of 181 consecutive anatomic segmentectomies (114 Open, 67 VATS) were performed for Stage IA (n=110) or IB (n=71) NSCLC from 2002–2006. A VATS approach was employed in 67 patients, and an open approach in 114 patients. Outcome variables include hospital course, complications, mortality, recurrence patterns and survival. Results: The mean age was 70 years (range: 45–100). Average tumor size was 2.3 cm (2.0 cm VATS; 2.4 cm open, NS). Lymph node sampling or dissection was performed in 169 (93%) of patients with an average node harvest of 8.2 nodes (Open = 9.2; VATS = 6.2, p=0.006). There were two perioperative deaths (1.1%), both open. Complications occurred in 59 patients (33%). Median length of stay was 6 days (VATS=5, Open=7). Mean follow-up was 15.6 months. There were fewer major (7 vs. 31, p=0.005) and infectious (3 vs. 12%, p=0.026) complications in the VATS group, with no significant difference in pulmonary complications or air leaks. Twenty-nine recurrences (16%; VATS=7, Open=22) occurred at a mean of 12.7 months [11 locoregional (6%), 18 distant (10%)]. Overall mortality, complications, recurrence and two-year actuarial survival (78%) were similar between VATS and open segmentectomy. Conclusions: VATS segmentectomy can be performed safely with acceptable morbidity, mortality, recurrence and survival. The VATS approach affords a shorter length of stay and fewer postoperative complications (major and infectious) compared with open techniques. The potential benefits of segmentectomy will need to be further validated by prospective, randomized trials (ACOSOG Z4032). Sublobar resection techniques represent an important adjunct in treating compromised patients with early stage NSCLC.

No significant financial relationships to disclose.

Hemodynamic, autonomic and neurohormonal behaviour of familial amyloidotic polyneuropathy and neurally mediated syncope patients during supine and orthostatic stress

Orthostatic intolerance (OI) syndromes are frequent and share symptoms like dizziness and orthostatic syncope. Their pathophysiology however seems to be different. The aim of our work was to evaluate autonomic and hemodynamic behaviour in patients with familial amyloidotic polyneuropathy and neurally mediated syncope in supine position and after acute orthostatic passive stress. We studied 12 patients with autonomic failure (group A), 12 patients with neurally mediated syncope (group B) and 16 aged matched normal controls (group C), in supine position and during the first 10 min of head-up tilt test (HUTT). Beat-by-beat blood pressure and heart rate were continuously monitored and digitised at 500 Hz. The baroreceptor alfa-index gain (vagal reflex-BRG), high frequency of RR variability (HFRR, vagal tonus) and low frequency of systolic arterial pressure variability (LFSAP, sympathetic tone) were calculated. Catecholamines, plasma brain (BNP) and atrial natriuretic (ANP) peptides were also measured. Hemodynamic data were derived and calculated by the non-invasive modelflow method. During supine position, cardiac output (CO) and stroke volume (SV) were similar in all groups. Mean arterial pressure (MAP) and BNP were higher in group A. Noradrenaline (NOR), BRG, HFRR and LFSAP were extremely low in this group. BRG and adrenaline (ADR) were higher in group B than in controls. Within the first 10 min of HUTT, there was a huge drop of CO, SV and MAP in group A, maintenance of very low levels of neurohormones and lack of autonomic function. HR, LFSAP and ADR had a higher rise at HUTT in group B compared with controls (p<0.01) but a significant decrease of BRG was noted (p<0.05). ANP or BNP did not change with tilt in any group. Different orthostatic intolerance syndromes may show important hormonal, autonomic and hemodynamic differences during supine rest and enhanced after passive orthostatism.

Influence of antipyretic drugs on the labeling of blood elements with technetium-99m

Acetaminophen (AAP), acetylsalicylic acid (ASA) and dipyrone (DIP) are antipyretic and analgesics drugs that have wide use in health sciences. Some drugs can modify the labeling of blood elements with technetium-99m (99mTc). This work has evaluated the effect of AAP, ASA and DIP on the labeling of the blood elements with 99mTc. Blood was incubated with different concentrations of the drugs before the 99mTc-labeled process. Plasma (P), blood cells (BC), insoluble (IF-P, IF-BC) and soluble (SF-P, SF-BC) fractions were separated and percentage of radioactivity (%ATI) in each fraction was determined. Data have shown that the antipyretic drugs used in this study did not significantly modify the fixation of 99mTc on the blood elements when the experiments were carried out with the doses usually used in human beings. Although the experiments were carried out with rats, it is possible to suggest that AAP, ASA or DIP should not interfere with the procedures in nuclear medicine involving the labeling of blood elements with 99mTc.

Hepatocytes cultured in alginate microspheres: an optimized technique to study enzyme induction

An important application of hepatocyte cultures is identification of drugs acting as inducers of biotransformation enzymes that alter metabolic clearance of other therapeutic agents. In the present study we optimized an in vitro system with hepatocytes cultured in alginate microspheres that allow studies of enzyme induction with excellent sensitivity. Induction factors obtained with standard inducers, such as 3-methylcholanthrene or phenobarbital, were higher compared to those with conventional hepatocyte co-cultures on collagen coated dishes. This is illustrated by activities of 7-ethoxyresorufin-O-deethylase (EROD) after incubation with 5 microM 3-methylcholanthrene (3-MC), a standard inducer for cytochrome P4501A1 and 1A2. Mean activities for solvent controls and 3-MC exposed cells were 2.99 and 449 pmol/min/mg protein (induction factor: 150) for hepatocytes cultured in microspheres compared to 2.72 and 80.6 pmol/min/mg (induction factor: 29.6) for hepatocytes on collagen coated dishes. To compare these in vitro data to the in vivo situation male Sprague Dawley rats, the same strain that was used also for the in vitro studies, were exposed to 3-MC in vivo using a protocol that guarantees maximal induction. Activities were 29.2 and 1656 pmol/min/mg in liver homogenate of solvent and 3-MC treated animals (induction factor: 56.7). Thus, the absolute activities of 3-MC exposed hepatocytes in microspheres are lower compared to the in vivo situation. However, the induction factor in vitro was even higher compared to the in vivo situation (150-fold versus 56.7-fold). A similar scenario was observed using phenobarbital (0.75 mM) for induction of CYP2B and 3A isoenzymes: induction factors for testosterone hydroxylation in position 16beta were 127.5- and 50.4-fold for hepatocytes in microspheres and conventionally cultured hepatocytes, respectively. The new in vitro system with hepatocytes embedded in solid alginate microspheres offers several technical advantages: (i) the solid alginate microspheres can be liquefied within 60s, allowing a fast and complete harvest of hepatocytes; (ii) alginate capsules are stable allowing transport and mechanical stress; (iii) high numbers of hepatocytes can be encapsulated in short periods; (iv) defined cell numbers between 600 hepatocytes, the approximate number of cells in one capsule, and 18 x 10(6) hepatocytes, the number of hepatocytes in 6 ml alginate, can be transferred to a culture dish or flask. Thus, encapsulated hepatocytes allow a flexible organization of experiments with respect to cell number. In conclusion, we optimized a technique for encapsulation of hepatocytes in alginate microspheres that allows identification of enzyme induction with an improved sensitivity compared to existing systems.

Detection and identification of mycobacteria in the Lisbon water distribution system

Mycobacteria have emerged as a major cause of opportunistic infections. Until the present, only a few studies have characterized mycobacteria present in the water distribution system of urban areas. In this study, we characterize these microorganisms in the Lisbon water distribution system. Our results indicate a high rate of positivities (90.5%) with mainly saprophytic mycobacteria. Around 63% of these results belong to strains of Mycobacterium gordonae indicating a generalized proliferation of this species in the Lisbon water distribution system. A total of 21.05% of the isolates are from M. kansasii, M. intracellulare and M. chelonae.

Echinoderm adhesive secretions: from experimental characterization to biotechnological applications

Adhesion is a way of life in echinoderms. Indeed, all the species belonging to this phylum use adhesive secretions extensively for various vital functions. According to the species or to the developmental stage considered, different adhesive systems may be recognized. (1) The tube feet or podia are organs involved in attachment to the substratum, locomotion, feeding or burrowing. Their temporary adhesion relies on a duo-gland adhesive system resorting to both adhesive and de-adhesive secretions. (2) The larval adhesive organs allow temporary attachment of larvae during settlement and strong fixation during metamorphosis. (3) The Cuvierian tubules are sticky defence organs occurring in some holothuroid species. Their efficacy is based on the instantaneous release of a quick-setting adhesive. All these systems rely on different types of adhesion and therefore differ in the way they operate, in their structure and in the composition of their adhesive. In addition to fundamental interests in echinoderm bioadhesives, a substantial impetus behind understanding these adhesives are the potential technological applications that can be derived from their knowledge. These applications cover two broad fields of applied research: design of water-resistant adhesives and development of new antifouling strategies. In this context, echinoderm adhesives could offer novel features or performance characteristics for biotechnological applications. For example, the rapidly attaching adhesive of Cuvierian tubules, the releasable adhesive of tube feet or the powerful adhesive of asteroid larvae could each be useful to address particular bioadhesion problems.