Bioecological aspects of triatomines and marsupials as wild Trypanosoma cruzi reservoirs in urban, peri-urban and rural areas in the Western Brazilian Amazon

In the Amazon region, Trypanosoma cruzi transmission cycles involve a great diversity of Triatominae vectors and mammal reservoirs. Some Rhodnius spp. mainly inhabit palm trees that act as microhabitats for hosts and vectors. The current study aimed to describe aspects of the bio-ecology of the vectors and reservoirs of T. cruzi in relation to human populations resident near areas with large quantities of palm trees, in rural, peri-urban and urban collection environments, located in the Western Brazilian Amazon. Rhodnius pictipes and Didelphis marsupialis were respectively the most predominant vector and reservoir, with rates of 71% for R. pictipes and 96.5% for D. marsupialis. The vast majority of T. cruzi isolates clustered with TcI. The most prevalent haplotype was TcI COII1 (69.7%). Mauritia flexuosa and Attalea phalerata were the main ecological indicators of infestation by triatomines. Birds were the most common food source (27,71%). T. cruzi isolated from R. robustus has the haplotype HUM-13, previously detected in a chronic Chagas patient living in the same area. Our results demonstrate the relevance of this study, with the occurrence of elevated infection rates in animals, and suggest the importance of the Amazon zones where there is a risk of infection in humans.

165 CRYOPRESERVATION OF IN VITRO PRODUCED BOVINE EMBRYOS AFTER LIPID DECREASE WITH FORSKOLIN

Forskolin® (F-6886) is being used to induce lipolysis and increase cryotolerance, to be an activator of adenylate cyclase, and elevating the cyclic adenosine monophosphate (cAMP) levels. The objective of this experiment was to induce the chemical lipolysis of embryos to improve vitrification and the hypothesis would be that Forskolin decrease the amount of lipid droplets, improve the production of blastocysts, and increase the survival rate after vitrification and warming. Eight random effect were performed which oocytes (N = 1172) were matured in TCM 199® supplemented with 10% of fetal bovine serum (FBS), under 5% CO2 atmosphere, at a temperature of 38.5°C and absolute humidity for 24 h. Semen was selected by Percoll gradient with a final concentration of the 2 × 106 sperm mL–1. Presumptive zygotes were cultured in SOFaa and 2.5% of FBS and were kept in an incubator with 5% CO2, 5% O2 and 90% N2 at 38.5°C and absolute humidity until Day 6, when Forskolin was added and remained until Day 7; control (group without Forskolin); F 2.5 µM (group with 2.5 µM Forskolin); F 5 µM (group with 5 µM Forskolin). On Day 7 (Day 0 = IVF) the rate of blastocyst formation was observed then they were vitrified. Apoptosis was analysed using the TUNEL technique, and the lipid content analysis was performed with Sudan Black B® (S-0395). To estimate the lipid content of embryos, 1 photo at a blastocyst group was performed and submitted to the program ImageJ 1.14 (Wayne Rasband, National Institutes of Health, Bethesda, MD, USA). The embryos were limited to obtain the area (μm2), and gray intensity mean (arbitrary units), and gray intensity per area was calculated (arbitrary units/μm2). Data were analysed by ANOVA with PROC GLM of SAS (SAS Institute, Cary, NC, USA). Sources of variation in the model including treatment and replicas were regarded as fixed and random effects, respectively. Data are presented as mean and standard least-squares error. For all analyzes was adopted the significance level of 5%. There was no difference in blastocyst rate: control (37.0 ± 4.0%), F 2.5 μM (38.6 ± 4.0%), F 5 μM (40.7 ± 4.0%). There were difference in lipids content between all groups: control (136.8 ± 2.2ab); F 2.5 μM (128.5 ± 2.2b), F 5 μM (135.6 ± 2.3c; P < 0.05). The F 2.5 μM group showed the higher rate of apoptotic cells compared to other groups: control (12.1 ± 3.5%a), F 2.5 μM (16.7 ± 4.1%b), F 5 μM (11.1 ± 6.5%a; P < 0.05). After vitrification, there was no difference in re-expansion: control (71.3 ± 8.9%), F 2.5 μM (73.1 ± 8.9%); F 5 μM (66.1 ± 8.9%) and apoptosis rate: control (22.3 ± 3.1%); F 2.5 μM (37.3 ± 3.8%); F 5 μM (33.2 ± 6.5%) between the groups. The Forskolin was effective at lower concentration to diminish lipids concentrations in embryos. But when we analysed the apoptotic cell, the lower concentration of Forskolin damaged embryos, but this effect could be diminished after vitrification and warming, when the drug did not increase the apoptotic cells. However, we need to study other concentrations of Forskolin. FAPESP (2010/50410–2/2014/21289–1) is acknowledged for support.

282 DIFFERENT CONCENTRATIONS OF FORSKOLIN FOR MEIOSIS BLOCK AND TO IMPROVE IN VITRO PRODUCTION OF BOVINE EMBRYOS

The inhibition of nuclear maturation allows time for the oocyte to accumulate molecules that are important for embryonic development. It was suggested that the inhibition of spontaneous nuclear IVM might allow for more time to accumulate the molecules important for embryonic development. The objective of this work was to evaluate blocking oocyte meiosis with the addition of forskolin. Slaughterhouse-derived bovine Zebu ovaries were collected and carried to the laboratory. Oocytes (n = 584) with at least 3 intact layers of cumulus cells and homogeneous cytoplasm were selected for IVM. The oocytes were transferred to drops of TCM 199 plus 10% FCS and hormones. The oocytes remained in IVM medium in 3 different concentrations of forskolin (6886), 0.1, 0.05, 0.025 mM, and a control group (withouth forskolin), for 6 h. Then they were maturated for an additional 18 h in forskolin-free medium. The first period above was an attempt to block (Block) and the second to resume (Res) the oocyte meiosis. The oocytes were incubated in a humidified atmosphere with 5% CO2 at 38.5°C in an air incubator. The oocytes were assessed for the stage of nuclear maturation, to see if they were in M II. Then oocytes were in vitro fertilized (IVF) with frozen Nelore bull semen (Bos taurus indicus). Presumptive zygotes (20–30/group) were cultured in SOFaa (synthetic oviducal fluid) supplemented with 5 mg mL–1 of BSA; the embryos were kept in an incubator with 5% CO2, 5% O2, and 90% N2 at 38.5°C and absolute humidity. On Day 7 (Day 0 = IVF) the blastocyst, the number of viable cells, and apoptosis rate (terminal deoxynucleotide transferase uridine nick-end labelling) were observed. Data were analysed with ANOVA using SAS PROC GLM (SAS Inst. Inc., Cary, NC, USA). Sources of variation in the model, including treatment and replication, were respectively considered fixed and random effects. If ANOVA was significant, the contrasts of means were performed using the least-squares difference. Data are presented as the mean and the standard error of least-squares. For all analyses, we used a significance level of 5%. No differences were observed for the stage of nuclear maturation of the oocyte (N = 336; control: 67.7 ± 8.3; F 0.025 mM, Block/Res: 67.7 ± 8.9; F 0.05 mM, Block/Res: 65.9 ± 9.8; F 0.1 mM, Block/Res: 50.2 ± 8.9), the blastocyst rate (N = 584; Control: 36.7 ± 3.7; F0.025 mM, Block/Res: 32.6 ± 3.7; F0.05 mM, Block/Res: 29.2 ± 3.7; F0.1 mM, Block/Res: 25.1 ± 3.7), and total number of intact cells (N = 10–15 embryos/group; Control:140.1 ± 13.0; F0.025 mM, Block/Res: 129.9 ± 13.0; F0.05 mM, Block/Res: 139.0 ± 13.0; F0.1 mM, Block/Res: 104.4 ± 13.0; P > 0.05). However, a higher rate of apoptosis was observed in the blastocysts produced from oocytes blocked for 6 h with the higher concentration of forskolin (N = 10–15 embryos/group): Control: 12.1 ± 2.5a; F 0.025 mM, Block/Res: 12.9 ± 2.5a; F0.05 mM, Block/Res: 13.5 ± 2.5a; F 0.1 mM, Block/Res: 30.2 ± 2.5b (P < 0.05). We conclude that all the experimental groups reached the stage of M II after the addition of forskolin and the highest concentration of forskolin caused cellular degeneration without harming embryo production on the seventh day.

161 USE OF FORSKOLIN TO DELAY MEIOSIS AND PRODUCE IN VITRO BOVINE EMBRYOS

The maintenance of oocytes in germinal vesicle (GV) stage for a few hours could result in more competent oocytes for use in biotechnology. This study aimed to show if the use of forskolin is able to inhibit and reverse the maturation in bovine oocytes, producing a higher rate of in vitro embryos without apoptosis rates. Eight replicates in total were performed. Nellore oocytes were matured in TCM-199 and to delay meiosis, the oocytes (n = 584) were maintained for 6 h in medium in presence of 0.025, 0.05, or 0.1 mM Forskolin. Then, the oocytes were cultured for 18 h in agent-free medium to resume meiosis. After resumption of meiosis, the oocytes (n = 336) were stained with Hoechst 33342 to evaluate the state of the nucleus: germinal vesicle (GV), germinal vesicle breakdown (GVBD), metaphase I (MI), metaphase II (MII), or degenerated or unidentified (D/U). Then (Day 0) oocytes were fertilized in human tubal fluid (Irvine, New Zealand) and the presumed zygotes were culture in SOFaa + 0.6% BSA + 2.5% FCS until Day 7, when the blastocyst (n = 177) rate was evaluated. Apoptosis in blastocysts was assessed by terminal deoxynucleotidyl transferase uracil nick-end labeling (TUNEL) reaction. Data were analysed by ANOVA, followed by Tukey test using the general linear model (PROC GLM) of SAS (SAS Institute Inc., Cary, NC, USA). The level of significance adopted was 5%. There were no statistical differences in state of the nucleus, only in MI (Control = GV: 0.0, GVBD: 0.8, MI: 8.3a, MII: 67.7, D/U: 7.3; F 0.025 mM = GV: 2.8, GVBD: 0.7, MI: 20.8ab, MII: 67.7, D/U: 8.9; F 0.05 mM = GV: 0.0, GVBD: 4.4, MI: 15.8ab, MII: 65.9, D/U: 13.7; and F 0.1 mM = GV: 0.0, GVBD: 1.0, MI: 34.1b, MII: 50.2, D/U: 14.6; P < 0.05). There were no statistical differences in blastocyst rate (Control: 36.7, F 0.025 mM: 32.6, F 0.05 mM: 29.2 and F 0.1 mM: 25.1 – P > 0.05). But when we analysed the apoptosis rate, differences were found among groups: (Control: 12.1a, F 0.025 mM: 12.9a, F 0.05 mM: 13.5a and F 0.1 mM: 30b; P < 0.05). Although Forskolin was able to inhibit meiosis and produce embryos at the same rates as controls, the higher dosage of this drug damaged the embryos. The authors acknowledge FAPESP 10/50410-2 for support.

[Radiofrequency catheter ablation of type I atrial flutter]

PURPOSE

To verify the efficacy and safety of the creation of a barrier with radiofrequency (RF) in the tricuspid annulus and the vena cava ostium (TA-IVC).

METHODS

Nine consecutive patients, 7 males, with age ranging from 36 to 76 years, with paroxysmal (7 patients) or permanent (2) type I atrial flutter (negative P wave in lead II, III and F) were submitted to RF ablation of TA-IVC istmo. One deflectable catheter with 4mm size tip was introduced into the right ventricle apex and pulled back to the inferior vena cava. When the atrial electrogram was detected the RF application was started. The RF was applied (20 watts during 60s) up to the proximity of inferior vena cava ostium. The end point was to stop atrial flutter. Then a vigorous atrial stimulation protocol, including isoproterenol infusion was used. In the next day, patients were submitted to transesophageal stimulation with the same protocol.

RESULTS

Atrial flutter was interrupted in all patients (100%) with 4 to 28 (mean 16.7 +/- 7.7) applications. Eight patients (88.8%) with one session and 1 (11.1%) with two sessions. The mean time spent to stop the atrial flutter with one application was 30.5 +/- 18.5s. There were no complications. After a mean follow up of 3 +/- 1.6 month all patients (100%) are asymptomatic. Two of them are taking propranolol to control symptomatic atrial and ventricular ectopic beats.

CONCLUSION

RF ablation of the TA-IVC istmo is efficient and safe in a short term follow up to interrupt and prevent re-induction and recurrence of type I atrial flutter.

[The pseudo-pacemaker syndrome]

We describe three cases of the pseudo-pacemaker syndrome. One of them due to selective fast pathway fulguration of atrioventricular nodal reentrant tachycardia and two others have occurred in spontaneous form. All cases were related with the presence of first-degree atrioventricular block and sinus node tachycardia. The treatment was done with complete atrioventricular block induction catheter ablation and permanent pacemaker implantation in two patients. In conclusion, the procedure of radiofrequency ablation to control AV nodal reentry tachycardia must preserve the fast nodal pathway in order to avoid the pseudo-pacemaker syndrome and this syndrome can spontaneously occur and must be considered during investigation of etiology of syncope.

[Reproducibility of head-up tilt test in patients with neurocardiogenic syncope]

PURPOSE

In order to identify the reproducibility of head-up tilt test, a second test one week later in 22 patients with a positive first test, was performed.

METHODS

The test was performed in a fasting state during the morning. The heart rate and blood pressure were monitored during 20 minutes in the supine position and then at 60 degrees for up to 40 minutes. The test were considered positive if the patient experienced syncope or pre-syncope with fall in systolic blood pressure > 30mmHg. The following aspects were evaluated: reproducibility of the positive response; the type of response (hypotension, asystole or hypotension plus bradycardia) and the time interval between tilt and the beginning of symptoms.

RESULTS

Eighteen (82%) patients had a second positive response; 14 (77.8%) of then had the same type of response; and 17 (94%) had syncope in similar time interval after tilt.

CONCLUSION

The head-up tilt testing has good reproducibility, although its use in the therapeutic management needs a longer period of evaluation.

[Diagnostic value of the tilt test in the evaluation of syncope of unknown origin. Preliminary results]

PURPOSE

In order to identify neurally mediated syncope, head-up tilt testing was performed in patients with recurrent unexplained syncope.

METHODS

The tests were performed in 125 patients in the fasting state, between 8:30 and 11:30 a.m. The blood pressure and heart rate were continuously monitored during 20 minutes in the resting state, and then, positioned at 60 degrees angle, for up to 40 minutes. A group of 20 patients with first negative test was submitted to intravenous isoproterenol in bolus of 2 micrograms every 2 minutes until symptoms occur or at a total dose of 8 micrograms. The test was considered positive when systolic blood pressure decreased at least 30 mmHg and the patient experimented syncope or pre-syncope.

RESULTS

In 52 patients the test was positive (41.6%), 63.5% of which had hypotension exclusively; 7.7% asystole; and 28.8% had hypotension and bradycardia. Nine of the 20 patients submitted to isoproterenol test were positive (45%). All patients recovered spontaneously after returning to supine position.

CONCLUSION

Head-up tilt testing is a safe and effective method for the identification of neurally mediated syncope.

[Thrombolytic treatment in pulmonary thromboembolism in the postoperative period following heart surgery complicated by ischemic cerebrovascular attack]

A 69 years old man with pulmonary embolism early after coronary bypass surgery complicated by ischemic stroke received thrombolytic therapy. Reperfusion of the pulmonary artery was achieved. Conversion of the ischemic stroke to hemorrhagic infarction was observed at the CT-Scan without neurological impairment.

[Salvage coronary angioplasty in a young patient with Takayasu arteritis and myocardial infarction]

A 16 year old boy with Takayasu's disease was admitted with myocardial infarction. Thrombolytic therapy with intravenous streptokinase showed no signs of reperfusion. Rescue angioplasty of the left descending coronary artery was performed with success.

[Evaluation of cardiac manifestations in hypothyroidism: documentation of reversibility]

PURPOSE

To detect the cardiac manifestations due to the state of hypothyroidism and reversibility after euthyroidism.

PATIENTS AND METHODS

Thirteen patients with documented primary hypothyroidism were evaluated through the echocardiography and other noninvasive techniques. A new evaluation was performed six months after thyroid hormone therapy.

RESULTS

Most of the changes were reversed after the patients became euthyroid. The main finding was the echocardiographic measurement of the velocity of circumferential fiber shortening that showed a significant positive linear correlation with serum thyroid hormones.

CONCLUSION

These data demonstrate the existence of a hypothyroid cardiomyopathy.

[Sporotrichosis]

Sporotrichosis is the most common deep mycosis in many tropical regions. The etiologic agent, Sporotrichum schenckii, is easily cultivated but rarely seen in histologic sections.