Shiga toxin-producing Escherichia coli (STEC): Zoonotic risks associated with psittacine pet birds in home environments.

Psittacidae are frequently bred as pets worldwide, but little is known about the zoonotic risks of these animals. The objective of this study was to investigate the presence of Shiga toxin-producing Escherichia coli (STEC) in the feces of psittacine birds housed as pets. A total of 171 fecal samples (67 cockatiels, 59 budgerigars, and 45 agapornis) were cultured. Forty-two (E. coli) strains were identified, and the presence of the eae, stx1, and stx2 genes was determined using PCR. The antimicrobial resistance profiles of the STEC strains were determined using the disk diffusion method and phylogenetic analysis according to the new Clermont phylotyping method. Using these methods, 19.4% (8/42) of the STEC strains were determined to be positive for the eae and stx2 genes. The results revealed a STEC frequency of 4.6% in the birds (8/171), with a percentage of 8.47% in budgerigars (5/59), 4.47% in cockatiels (3/67), and 0% in agapornis (0/45). None of the STEC isolates belonged to the O157 serogroup. Most of the strains were classified as sensitive to the 18 antibiotics tested. None of the strains exhibited a multiresistance profile. In the phylogenetic analysis, two strains were classified as non-typeable, three were classified as B2, two were classified as F, and one was classified as Clade I. Seven of the eight STEC strains showed a clonal profile using AFLP. E. coli strains that are stx2(+) plus eae(+) are usually associated with severe human diseases such as hemorrhagic colitis and hemolytic-uremic syndrome. The STEC-positive results indicate the zoonotic risk of breeding psittacidae in home environments.

Nicotine-induced nystagmus: three-dimensional analysis and dependence on head position.

Two- and three-dimensional analyses of nicotine-induced eye movements were performed in 53 subjects to evaluate whether they were primarily of vestibular or ocular motor origin. Nicotine-induced nystagmus was detected in 27 subjects (51%); in 25 of these (93%) it was modulated by otolith input. Three-dimensional analysis of nicotine-induced nystagmus revealed that it violates Listing's law. Taken together, these findings suggest that nicotine induces an imbalance in the vestibulo-ocular reflex.

Long-term, high-dose dietary exposure of rainbow trout to butylated hydroxyanisole is non-carcinogenic.

The hepatocarcinogenic and/or promotional properties of butylated hydroxyanisole (BHA) were tested in rainbow trout. Four groups of 100, 21-day-old trout embryos were exposed to 0.5 ppm aqueous aflatoxin B1 (AFB1) for 30 min, and four similar groups were sham treated. After hatching, swim-up, and the onset of vigorous feeding behavior (2 weeks pest swim-up), duplicate groups of 60 AFB1-treated and sham-treated fry were started on a test diet containing 0.6% (6000 ppm) BHA, and the other duplicate groups of treated and untreated fry were fed the control Oregon Test Diet (OTD). After 8 months of feeding BHA or OTD, the fish were necropsied for tumor detection, with particular attention given to the stomach and liver. No tumors were seen in the livers or stomachs of the sham-treated fish fed OTD or BHA, showing that BHA is not carcinogenic to rainbow trout under the conditions of this experiment. Promotional results were equivocal, with one tank of fish having a higher hepatic tumor incidence, but the other the same as the positive AFB1 control. When the tanks were combined, however, there was no statistical difference between the two groups.

Smoking and balance: correlation of nicotine-induced nystagmus and postural body sway.

Unaccustomed smoking may elicit transient nystagmus, dizziness, unsteadiness, and nausea. Infrared videonystagmography and posturography were performed simultaneously to study the differential effects of nicotine on the association of ocular motor and postural disturbances in 25 non- or occasional smokers. Sixteen showed nicotine-induced nystagmus (NIN) of various directions (mainly horizontal or upbeat) which was associated with a significant increase in postural sway after smoking a cigarette (total sway path (SP) before smoking 2.22 +/- 0.82 m/min (mean +/- s.d.), 1 min after smoking 3.83 +/- 1.41 m/min; p < 0.0004, ANOVA); nine showed neither effect. There was a high correlation between the intensity of the nystagmus (measured as peak slow phase velocity) and the increase in total SP (correlation coefficient 0.78) as well as the time courses of both. Visual fixation of an LED integrated in the mask not only caused a suppression of NIN but also a decrease in body sway. Transient ocular motor and postural effects are compatible with simultaneous nicotine-induced effects on the vestibulo-ocular and vestibulo-spinal functions.

Application of matrix solid-phase dispersion in the determination of dibenzo[a,l]pyrene content of experimental animal diets used in a large-scale tumor study.

A method utilizing matrix solid-phase dispersion (MSPD) was developed for isolation and determination of dibenzo[a,l]pyrene (DBP) in experimental rainbow-trout diets used in a large-scale carcinogenesis study. A 0.5 g sample of moist ration containing 0-225 ppm DBP (dry basis) was mixed with 2 g C18 sorbent and benzo[a]pyrene internal standard was added to the mixture. Extraction and clean-up were accomplished in a single step by extracting the sample mixture with hexane-benzene 4:1 from a cartridge containing 2 g Florisil. DBP was quantified by HPLC on a C5 bonded phase column with fluorescence detection. Mean analytical recovery of DBP from control diet spiked at three concentration levels was 101 to 107% with relative standard deviations of 1 to 7%. The limit of detection of DBP was equivalent to 0.014 ppm in the ration. Application of the method to verification of DBP levels in trout rations from the carcinogenesis study is described. Control ration (0 ppm DBP) was screened for possible DBP contamination and none was found. This is the first report on analysis of DBP in experimental animal diets.

Electrophysiologic effects of disopyramide in Chagas' disease with bundle branch block.

We report the acute electrophysiologic effects of disopyramide in 16 asymptomatic chagasic individuals with right bundle branch block. The drug increased the heart rate, prolonged the H-V interval and enhanced the conductivity through the A-V node.

Effects of atenolol in patients with reciprocating supraventricular tachycardia.

We studied 12 patients with crisis of paroxysmal reciprocating supraventricular tachycardia before and after intravenous injection of 5 mg of atenolol. The patients were then followed for periods ranging from 6 to 50 months (median 34 months). During this time, they received oral atenolol therapy, at 200 mg for the first two weeks, and 100 mg daily thereafter. Tachycardia was due to reciprocation within the atrioventricular node in 9 patients, and to pre-excitation in 3 patients. Atenolol slowed the sinus rate, prolonged the atrioventricular conduction time, and increased the atrial cycle length at which atrioventricular nodal Wenckebach phenomenon occurred. During the tachycardia, atenolol increased the tachycardia During the tachycardia, atenolol increased the tachycardia cycle length, due to prolongation of the intranodal atrioventricular conduction time. Of the 11 patients who were observed for the full period, 7 had no further episodes of arrhythmia. One patient (with left-sided pre-excitation) failed to respond to any antiarrhythmic medication, one patient remained free of symptoms for two years, but received an atrial pacemaker for control of the tachycardia at the end of this period. Two patients (one with dual atrioventricular nodal pathways, and one with concealed left-sided pre-excitation) await other treatment for their tachycardia, after remaining free of symptoms for one and two years, respectively. These findings suggest that atenolol is an effective beta blocker for use in controlling arrhythmias in patients with reciprocating supraventricular tachycardia, for use in once daily dosage, and is a medication largely free of side effects.

Exercise testing in the latent phase of Chagas' disease.

Exercise stress testing was performed in 50 completely asymptomatic patients in the latent phase of Chagas' disease. In 32 (64%) abnormalities were found consisting of either abnormal ST depression, exercise-induced arrhythmias, or chronotropic incompetence. The latter was determined by comparing the heart rate response to 50 age- and sex-matched control patients without serologic evidence of Chagas' disease. In the absence of an adequate control population we can only speculate as to the significance of the ST depression and arrhythmias during exercise. However, chronotropic incompetence may be a specific marker for Trypanosomal infestation in an endemic area. It probably is an early manifestation of autonomic dysfunction secondary to Chagas' disease.

[Benign paroxysmal positioning vertigo]. / Vertigem de posicionamento paroxística benigna.

Benign paroxysmal positioning vertigo is a frequent vestibular disorder. With a simple maneuver one can easily diagnose this condition and treatment is based on liberatory maneuvers. On this review the pathogenesis, the clinical features and different maneuvers are briefly discussed.

Musical hallucination associated with hearing loss / Alucinações musicais associadas a perda auditiva

In spite of the fact that musical hallucination have a significant impact on patients' lives, they have received very little attention of experts. Some researchers agree on a combination of peripheral and central dysfunctions as the mechanism that causes hallucination. The most accepted physiopathology of musical hallucination associated to hearing loss (caused by cochlear lesion, cochlear nerve lesion or by interruption of mesencephalon or pontine auditory information) is the disinhibition of auditory memory circuits due to sensory deprivation. Concerning the cortical area involved in musical hallucination, there is evidence that the excitatory mechanism of the superior temporal gyrus, as in epilepsies, is responsible for musical hallucination. In musical release hallucination there is also activation of the auditory association cortex. Finally, considering the laterality, functional studies with musical perception and imagery in normal individuals showed that songs with words cause bilateral temporal activation and melodies activate only the right lobe. The effect of hearing aids on the improvement of musical hallucination as a result of the hearing loss improvement is well documented. It happens because auditory hallucination may be influenced by the external acoustical environment. Neuroleptics, antidepressants and anticonvulsants have been used in the treatment of musical hallucination. Cases of improvement with the administration of carbamazepine, meclobemide and donepezil were reported, but the results obtained were not consistent.

Apesar das alucinações musicais causarem grandes repercussões na vida dos pacientes, sempre foram pouco valorizadas e estudadas pelos profissionais. Alguns investigadores sugerem uma combinação de disfunções periféricas e centrais como o mecanismo causador das alucinações. A fisiopatologia mais aceita entre os pesquisadores de alucinação musical associada à hipoacusia ou anacusia (causada por lesão coclear, de nervo coclear ou interrupção de informação na ponte ou mesencéfalo) é a desibinição de circuitos de memória auditiva devido à deprivação sensorial. Em relação às áreas corticais envolvidas na alucinação musical, há evidência de que um mecanismo excitatório no córtex temporal superior, como nas epilepsias, seja responsável pela alucinação musical. Finalmente, considerando a lateralidade, estudos funcionais de percepção e imagética em indivíduos normais mostraram que canções com letras levam a ativação temporal bilateral e melodias ativam apenas o lobo temporal direito. É bem documentado o efeito de aparelhos auditivos na alucinação musical através de uma melhora da perda auditiva. Neurolépticos, antidepressivos e anticonvulsivantes têm sido usados no tratamento de alucinação musical na experiência clínica, mas não há eficácia comprovada na maioria dos casos. Há casos descritos na literatura com melhora das alucinações musicais com uso de carbamazepina, meclobemide e donepezil, entretanto sem resultados consistentes.