Catheter ablation of atriofascicular Mahaim fibers guided by the activation potential

OBJECTIVE: To determine whether recording of the activation potential may be used as an isolated criterion to guide catheter ablation of atriofascicular Mahaim fibers. METHODS: We studied 6 patients (5 females, mean age of 26±7.3 years) with paroxysmal tachycardias with a wide QRS complex, whose electrophysiological study diagnosed atriofascicular Mahaim fibers. Mapping and catheter ablation were performed in sinus rhythm, guided only by the recording of the activation potential of the fiber. RESULTS: Efficacy in ablation was achieved in all patients. The fibers were located in the right lateral region of the tricuspid ring in 3 patients, right posterolateral region in 2, and right anterolateral region in 1. A mean of 5.3±3 radiofrequency applications was performed. The mean fluoroscopy time was 46.6±25 minutes, and the mean duration of the procedure was 178.6±108 minutes. No complication occurred. In a mean 20-month follow-up, all patients were asymptomatic and receiving no antiarrhythmic drugs. CONCLUSION: Catheter ablation of Mahaim fibers may be performed with good safety and efficacy by mapping the activation potential of the tricuspid ring in sinus rhythm.

Short- and midterm follow-up results of valvuloplasty with balloon catheter for congenital aortic stenosis

OBJECTIVE: To report short and midtem follow-up results of balloon aortic valvuloplasty to treat congenital aortic stenosis. METHODS: Seventy-five patients (median age: 8 years) underwent the procedure through the retrograde femoral or carotid route. RESULTS: The procedure was completed in 74 patients (98.6%). The peak-to-peak systolic gradient dropped from 79.6±27.7 to 22.3±17.8 mmHg (P<0.001), the left ventricular systolic pressure dropped from 164±39.1 to 110±24.8 mmHg (P<0.001), and the left ventricular end diastolic pressure dropped from 13.3±5.5 to 8.5±8.3 mmHg (P< 0.01). Four patients (5.3%) died due to the procedure. Aortic regurgitation (AoR) appeared or worsened in 27/71 (38%) patients, and no immediate surgical intervention was required. A mean follow-up of 50±38 months was obtained in 37 patients. Restenosis and significant AoR were observed in 16.6% of the patients. The estimates for being restenosis-free and for having significant AoR in 90 months were 60% and 50%, respectively. CONCLUSION: Aortic valvuloplasty was considered the initial palliative method of choice in managing congenital aortic stenosis, with satisfactory short- and midterm results.

Diversity and structure of microcrustacean assemblages (Cladocera and Copepoda) and limnological variability in perennial and intermittent pools in a semi-arid region, Bahia, Brazil

Temporary wetlands undergo recurrent drought due to the scarcity of water, which disrupts the hydrological connectivity with adjacent aquatic systems. However, some environments retain water for longer periods, allowing greater persistence of the community. The current study evaluated differences in the microcrustacean assemblages and limnological variability between perennial and intermittent pools in a semi-arid region of Brazil. The abiotic features (water temperature, pH, total alkalinity, electrical conductivity and depth) of intermittent pools were affected more than perennial pools due to loss of water volume. This may have contributed to a higher average richness and diversity index in some intermittent pools and differences in the structure of the assemblages. The lowest species richness and diversity were recorded where physical factors, such as a large quantity of suspended solids and variability in the electrical conductivity of the water and pH, make the environment unsuitable for these organisms. These results suggest that community development in intermittent pools is interrupted by the dry season; when the water returns, due to rainfall or rising groundwater, each pond undergoes a different process of colonization. In these circumstances, the biological importance of temporary aquatic environments is clear, since such pools provide shelters and have an important role in the maintenance of the regional diversity of aquatic environments.

Functional independence measure in patients with intermittent claudication

AbstractOBJECTIVEOf this study were to evaluate the functional independence of patients with intermittent claudication and to verify its association with sociodemographic and clinical variables, walking ability and physical activity level.METHODThis was a descriptive, exploratory, cross-sectional study with a quantitative approach. Fifty participants (66.4 years; 68% male) were recruited from Claudication Unit of a tertiary hospital. Functional Independence Measure were used to evaluate functional incapacity; the Baltimore Activity Scale, to estimate the physical activity level and the Walking Impairement Questionnaire, the walking ability.RESULTSParticipants had complete functional independence (124.8 + 2.0), low levels of physical activity (4.2 + 2.0), and impairment of walking ability; the worst performance was found in walking velocity domain (21.2 + 16.4). The functional independence score was associated with physical activity (r=0,402) and walking ability scores (distance, r=0,485; speed, r=0,463; stairs, r=0,337).CONCLUSIONIn conclusion, the level of functionality is associated with functional capacity in these patients.

Forage production of elephant grass under intermittent stocking

The objective of this work was to evaluate the dry matter production of elephant grass (Pennisetum purpureum) genotypes, managed under intermittent stocking. A completely randomized design was used, with two genotypes and three replicates. The treatments consisted of factorial combinations (2x2x2) of genotypes ('BRS Kurumi' and the clone CNPGL 00‑1‑3), two light interception levels (LI) at the onset of grazing (90 and 95%), and two post‑grazing canopy heights (30 and 50 cm). A total of 24 Holstein x Zebu crossbred heifers were used. The stocking density varied in order to finish the grazing periods in two days. The interval between the defoliation, based on 95% LI, resulted in a higher leaf mass per grazing cycle. The post‑grazing height of 30 cm did not affect the number of grazing cycles but provided a greater herbage accumulation rate. The cultivar BRS Kurumi has higher pasture growth, lower rest period, and greater number of grazing cycles, which results in increased forage production in the growing season.

Comparative dosimetry in intracavitary balloon catheter brachytherapy with I-125 and in Cf-252 brachytherapy combined with BNCT for brain tumors

Objective Comparative analysis of dosimetry in intracavitary balloon catheter brachytherapy with I-125 and in Cf-252 brachytherapy combined with BNCT for treatment of brain tumors. Materials and Methods Simulations of intracavitary balloon catheter brachytherapy with I-125 and in Cf-252 brachytherapy combined with BNCT were performed with the MCNP5 code, modeling the treatment of a brain tumor on a voxel computational phantom representing a human head. Absorbed dose rates were converted into biologically weighted dose rates. Results Intracavitary balloon catheter brachytherapy with I-125 produced biologically weighted mean dose rates of 3.2E-11, 1.3E-10, 1.9E-11 and 6.9E-13 RBE.Gy.h-1.p-1.s, respectively, on the healthy tissue, on the balloon periphery and on the I 1 and I 2 tumor infiltration zones. On the other hand, Cf-252 brachytherapy combined with BNCT produced a biologically weighted mean dose rate of 5.2E-09, 2.3E-07, 8.7E-09 and 2.4E-09 RBE.Gy.h-1.p-1.s, respectively on the healthy tissue, on the target tumor and on the I 1 and I 2 infiltration zones. Conclusion Cf-252 brachytherapy combined with BNCT delivered a selective irradiation to the target tumor and to infiltration zones, while intracavitary balloon catheter brachytherapy with I-125 delivered negligible doses on the tumor infiltration zones.

Cardiac tamponade in an infant during contrast infusion through central venous catheter for chest computed tomography

Complications from central venous catheterization include infectious conditions, pneumothorax, hemothorax and venous thrombosis. Pericardial effusion with cardiac tamponade hardly occurs, and in infants is generally caused by umbilical catheterization. The authors describe the case of cardiac tamponade occurred in an infant during chest computed tomography with contrast infusion through a central venous catheter inserted into the right internal jugular vein.

Presence of air in the hepatic portal system in association with umbilical venous catheter malposition

The authors report a case of umbilical venous catheter malposition with air in the portal venous system in a preterm neonate. Initially, the hypothesis of necrotizing enterocolitis was considered, but the newborn progressed with no finding of disease and the air disappeared at follow-up radiography. The differential diagnosis of such a finding can avoid unnecessary clinical treatments.

Nitrous oxide emissions from an intermittent aeration activated sludge system of an urban wastewater treatment plant

This study investigated the emission of N2O during the sequential aerated (60-min) and non-aerated (30-min) stages of an intermittent aeration cycle in an activated sludge wastewater treatment plant (WWTP). N2O emission occurred during both stages; however, emission was much higher during aeration. Air stripping is the major factor controlling transfer of N2O from the sewage to the atmosphere. The N2O emissions exclusively from the aeration tank represented 0.10% of the influent total nitrogen load and the per capita emission factor was almost 3 times higher than that suggested by the IPCC for inventories of N2O emission from WWTPs.

Alcohol dependence induced in rats by semivoluntary intermittent intake

The objective of the present experiment was to assess ethyl alcohol (ETOH) dependence brought about by a semivoluntary intermittent intake regimen in rats. Male Wistar rats weighing 150-250 g at the onset of the experiment were assigned to the following groups: 0% ETOH (N = 11), 5% ETOH (N = 20), 20% ETOH (N = 20) and 40% ETOH (N = 18). ETOH solutions were offered at the end of the day and overnight from Monday to Friday, and throughout weekends, for 90 days. The concentration of the ETOH solutions was increased in a stepwise fashion allowing the rats to get used to the taste of alcohol. Reposition of pure water was permitted during 1-h water drinking periods in the morning. Daily volume intake (± SEM) averaged 25.4 ± 0.4 ml (0% ETOH), 23.8 ± 0.6 ml (5% ETOH), 17.6 ± 0.7 ml (20% ETOH) and 17.5 ± 0.6 ml (40% ETOH). ETOH consumption differed significantly (P<0.05) among groups, averaging 4.4 ± 0.2 g kg-1 day-1 (5% ETOH), 10.3 ± 0.3 g kg-1 day-1 (20% ETOH) and 26 ± 1.2 g kg-1 day-1 (40% ETOH). Furthermore, ETOH detection in plasma 10-12 h after offering the solution indicated that its consumption in the 40% ETOH group was sufficient to override its metabolism. Overt signs of ETOH dependence, such as increased thirst, hyperactivity, puffing, hair ruffling and startle responsiveness as well as reduced drowsiness, were significantly increased in the 20% and 40% ETOH groups compared to the 0% and 5% groups. Accordingly, the model described here proved to be a useful tool for the evaluation of subtle or moderate behavioral and physical consequences of long-term ETOH intake

Uniform decrease of alpha-global field power induced by intermittent photic stimulation of healthy subjects

Nineteen-channel EEGs were recorded from the scalp surface of 30 healthy subjects (16 males and 14 females, mean age: 34 years, SD: 11.7 years) at rest and under trains of intermittent photic stimulation (IPS) at rates of 5, 10 and 20 Hz. Digitalized data were submitted to spectral analysis with fast fourier transformation providing the basis for the computation of global field power (GFP). For quantification, GFP values in the frequency ranges of 5, 10 and 20 Hz at rest were divided by the corresponding data obtained under IPS. All subjects showed a photic driving effect at each rate of stimulation. GFP data were normally distributed, whereas ratios from photic driving effect data showed no uniform behavior due to high interindividual variability. Suppression of alpha-power after IPS with 10 Hz was observed in about 70% of the volunteers. In contrast, ratios of alpha-power were unequivocal in all subjects: IPS at 20 Hz always led to a suppression of alpha-power. Dividing alpha-GFP with 20-Hz IPS by alpha-GFP at rest (R = alpha-GFP IPS/alpha-GFPrest) thus resulted in ratios lower than 1. We conclude that ratios from GFP data with 20-Hz IPS may provide a suitable paradigm for further investigations.

Effects of high-intensity intermittent training on carnitine palmitoyl transferase activity in the gastrocnemius muscle of rats

We examined the capacity of high-intensity intermittent training (HI-IT) to facilitate the delivery of lipids to enzymes responsible for oxidation, a task performed by the carnitine palmitoyl transferase (CPT) system in the rat gastrocnemius muscle. Male adult Wistar rats (160-250 g) were randomly distributed into 3 groups: sedentary (Sed, N = 5), HI-IT (N = 10), and moderate-intensity continuous training (MI-CT, N = 10). The trained groups were exercised for 8 weeks with a 10% (HI-IT) and a 5% (MI-CT) overload. The HI-IT group presented 11.8% decreased weight gain compared to the Sed group. The maximal activities of CPT-I, CPT-II, and citrate synthase were all increased in the HI-IT group compared to the Sed group (P < 0.01), as also was gene expression, measured by RT-PCR, of fatty acid binding protein (FABP; P < 0.01) and lipoprotein lipase (LPL; P < 0.05). Lactate dehydrogenase also presented a higher maximal activity (nmol·min-1·mg protein-1) in HI-IT (around 83%). We suggest that 8 weeks of HI-IT enhance mitochondrial lipid transport capacity thus facilitating the oxidation process in the gastrocnemius muscle. This adaptation may also be associated with the decrease in weight gain observed in the animals and was concomitant to a higher gene expression of both FABP and LPL in HI-IT, suggesting that intermittent exercise is a "time-efficient" strategy inducing metabolic adaptation.

Acute effects of resistance exercise and intermittent intense aerobic exercise on blood cell count and oxidative stress in trained middle-aged women

The aim of this study was to compare the effect of an intermittent intense aerobic exercise session and a resistance exercise session on blood cell counts and oxidative stress parameters in middle-aged women. Thirty-four women were selected and divided into three groups: RE group (performing 60 min of resistance exercises, N = 12), spinning group (performing 60 min of spinning, N = 12), and control group (not exercising regularly, N = 10). In both exercise groups, lymphocytes and monocytes decreased after 1-h recuperation (post-exercise) compared to immediately after exercise (P < 0.05). Immediately after exercise, in both exercised groups, a significant increase in TBARS (from 16.5 ± 2 to 25 ± 2 for the spinning group and from 18.6 ± 1 to 28.2 ± 3 nmol MDA/mL serum for the RE group) and protein carbonyl (from 1.0 ± 0.3 to 1.6 ± 0.2 for the spinning group and from 0.9 ± 0.2 to 1.5 ± 0.2 nmol/mg protein for the RE group) was observed (P < 0.05). A decrease in antioxidant activities (non-protein sulfhydryl, superoxide dismutase, catalase) was also demonstrated with a negative correlation between damage markers and antioxidant body defenses (P < 0.05). These results indicate that an acute bout of intermittent or anaerobic exercise induces immune suppression and increases the production of reactive oxygen species, causing oxidative stress in middle-aged and trained women. Furthermore, we demonstrated that trained women show improved antioxidant capacity and lower oxidative damage than sedentary ones, demonstrating the benefits of chronic regular physical activity.

Inflammation induced by increased frequency of intermittent hypoxia is attenuated by tempol administration

The levels of serum inflammatory cytokines and the activation of nuclear factor kappa B (NF-κB) and hypoxia inducible factor-1α (HIF-1α) in heart tissues in response to different frequencies of intermittent hypoxia (IH) and the antioxidant tempol were evaluated. Wistar rats (64 males, 200-220 g) were randomly divided into 6 experimental groups and 2 control groups. Four groups were exposed to IH 10, 20, 30, or 40 times/h. The other 2 experimental groups were challenged with IH (30 times/h) plus tempol, either beginning on day 0 (IH30T0) or on day 29 (IH30T29). After 6 weeks of challenge, serum levels of tumor necrosis factor (TNF)-α, intracellular adhesion molecule (ICAM)-1, and interleukin-10 were measured, and western blot analysis was used to detect NF-κB p65 and HIF-1α in myocardial tissues. Serum levels of TNF-α and ICAM-1 and myocardial expression of NF-κB p65 and HIF-1α were all significantly higher in IH rats than in controls (P<0.001). Increased IH frequency resulted in more significant changes. Administration of tempol in IH rats significantly reduced levels of TNF-α, ICAM-1, NF-κB and HIF-1α compared with the non-tempol-treated group (F=16.936, P<0.001). IH induced an inflammatory response in a frequency-dependent manner. Additionally, HIF-1α and NF-κB were increased following IH administration. Importantly, tempol treatment attenuated this effect.

Three days of intermittent stretching after muscle disuse alters the proteins involved in force transmission in muscle fibers in weanling rats

The aim of this study was to determine the effects of intermittent passive manual stretching on various proteins involved in force transmission in skeletal muscle. Female Wistar weanling rats were randomly assigned to 5 groups: 2 control groups containing 21- and 30-day-old rats that received neither immobilization nor stretching, and 3 test groups that received 1) passive stretching over 3 days, 2) immobilization for 7 days and then passive stretching over 3 days, or 3) immobilization for 7 days. Maximal plantar flexion in the right hind limb was imposed, and the stretching protocol of 10 repetitions of 30 s stretches was applied. The soleus muscles were harvested and processed for HE and picrosirius staining; immunohistochemical analysis of collagen types I, III, IV, desmin, and vimentin; and immunofluorescence labeling of dystrophin and CD68. The numbers of desmin- and vimentin-positive cells were significantly decreased compared with those in the control following immobilization, regardless of whether stretching was applied (P<0.05). In addition, the semi-quantitative analysis showed that collagen type I was increased and type IV was decreased in the immobilized animals, regardless of whether the stretching protocol was applied. In conclusion, the largest changes in response to stretching were observed in muscles that had been previously immobilized, and the stretching protocol applied here did not mitigate the immobilization-induced muscle changes. Muscle disuse adversely affected several proteins involved in the transmission of forces between the intracellular and extracellular compartments. Thus, the 3-day rehabilitation period tested here did not provide sufficient time for the muscles to recover from the disuse maladaptations in animals undergoing postnatal development.