Characterization of a novel citrus tristeza virus genotype within three cross-protecting source GFMS12 sub-isolates in South Africa by means of Illumina sequencing

Tristeza disease (caused by citrus tristeza virus, CTV) is currently controlled in South Africa by means of cross-protection. In this study, we characterized the CTV populations of three grapefruit mild strain 12 (GFMS12) single-aphid-transmission-derived sub-isolates at the whole-genome level using Illumina sequencing technology. A novel South African isolate (CT-ZA3, of the T68 genotype) was shown to be the dominant genotype in all GFMS12 sub-isolates tested, along with reads unique to various other genotypes occurring as minor components. Uncertainty remains as to the significance of these minor components.     

Atrial fibrillation in the Wolff-Parkinson-White syndrome.

Atrial fibrillation in patients with Wolff-Parkinson-White (WPW) syndrome may lead to syncope, ventricular fibrillation, and sudden death. In a follow-up study of 241 patients with WPW syndrome in a relatively unselected population, 26 patients had documented atrial fibrillation (11%). These patients were followed up after 1-37 years (median 11 years; mean 15 years). During this period, 2 of 26 died suddenly. These 2 patients had the shortest RR interval during spontaneous atrial fibrillation (less than or equal to 220 msec), greater than or equal to 1 episodes of syncope, and a persistent delta wave in all available electrocardiograms. In comparison, sudden or tachycardia-related death was seen in 4 of the 241 patients. This difference is not statistically significant. Thus, atrial fibrillation of 26 patients with WPW syndrome was surprisingly well tolerated in our follow-up study with only 2 sudden deaths.     

Serial pulmonary function tests in patients treated with low-dose amiodarone.

Problems with pulmonary toxicity have emerged as a potentially limiting factor for amiodarone use. We studied 24 consecutive patients receiving low-dose (i.e., less than or equal to 400 mg/day) amiodarone for refractory tachyarrhythmias. Serial pulmonary function test results were correlated with daily dose, serum concentration, cumulated dose, and duration of amiodarone treatment to determine the effect of the drug on pulmonary function. The mean follow-up period for the 24 patients, who completed baseline and follow-up evaluations, was 47 months (range 31 to 75 months). In 22 of the 24 patients a reduction in total diffusion capacity (TLCO) was noted after treatment; for all 24 patients the mean reduction in TLCO was 12.9% of the predicted value (SD 9.6% predicted) (p less than 0.02). The decrease in TLCO was found to be significantly related to an increasing cumulated dose of amiodarone (p = 0.007), whereas the reduction in TLCO was found to be unrelated to sex, age, underlying heart disease, arrhythmia, daily dose of amiodarone, duration of treatment, plasma concentration of amiodarone and desethylamiodarone, and pretreatment pulmonary function abnormalities. Seven (29%) of the patients had asymptomatic pulmonary toxicity with a decrease in TLCO greater than or equal to 20% of the predicted value. In conclusion, long-term treatment with low-dose amiodarone was associated with a substantial decrease in TLCO, a higher cumulative dose of the drug was related to an increasing reduction in TLCO, and pretreatment pulmonary function abnormalities were not predictive for development of subclinical pulmonary toxicity.     

Improvement in brainstem function during treatment of intracranial tuberculosis. A report of 2 cases

The auditory evoked response serves as a measure of brainstem integrity. Two cases are reported in which this investigation was used to monitor recovery from intracranial tuberculosis.     

Modulation of gamma oscillations by endogenous adenosine through A1 and A2A receptors in the mouse hippocampus

Adenosine serves as a homeostatic factor, regulating hippocampal activity through A₁ receptor-mediated inhibition. Gamma frequency oscillations, associated with cognitive functions, emerge from increased network activity. Here we test the hypothesis that hippocampal gamma oscillations are modulated by ambient adenosine levels.In mouse hippocampal slices exogenous adenosine suppressed the power of both kainate-induced gamma oscillations and spontaneous gamma oscillations, observed in a subset of slices in normal aCSF. Kainate-induced gamma oscillation power was suppressed by the A₁ receptor agonist PIA and potentiated by the A₁ receptor antagonist 8-CPT to three times matched control values with an EC₅₀ of 1.1 μM. 8-CPT also potentiated spontaneous gamma oscillation power to five times control values. The A_2A receptor agonist CGS21680 potentiated kainate-induced gamma power to two times control values (EC₅₀ 0.3 nM), but this effect was halved in the presence of 8-CPT. The A_2A receptor antagonist ZM241385 suppressed kainate-induced gamma power. The non-selective adenosine receptor antagonist caffeine induced gamma oscillations in slices in control aCSF and potentiated both kainate-induced gamma and spontaneous gamma oscillations to three times control values (EC₅₀ 28 μM).Decreasing endogenous adenosine levels with adenosine deaminase increased gamma oscillations. Increasing endogenous adenosine levels with the adenosine kinase inhibitor 5-iodotubericidin suppressed gamma oscillations. Partial hypoxia-induced suppression of gamma oscillations could be prevented by 8-CPT.These observations indicate that gamma oscillation strength is powerfully modulated by ambient levels of adenosine through A₁ receptors, opposed by A_2A receptors. Increased gamma oscillation strength is likely to contribute to the beneficial cognitive effects of caffeine.     

Comparison of different orthogonal systems in high resolution ECGs and the significance of the number of averaged beats in detecting late potentials

For non-invasive detection of late potentials in the signal-averaged electrocardiogram (SAECG) most studies use modified orthogonal leads. In the present study the significance of three different lead systems for the detection of late potentials was examined. SAECGs were recorded at five different (32, 64, 128, 256, and 512) numbers of averaged beats in 24 patients with ventricular tachycardia after myocardial infarction and in 76 normal subjects. The original Frank leads and two different modified orthogonal vector lead systems were used. There was no clinical difference between the three orthogonal systems in sensitivity and the difference in specificity (P less than 0.01) seemed to be primarily related to differences in noise content. When the vector systems were compared at equally low noise levels of 0.47-0.50 microV, the apparent differences in specificity between the vector systems disappeared. At decreasing noise levels the sensitivity increased, at the cost of a loss in specificity which at very low noise levels was out of proportion with the gain in sensitivity. A modified approach with a fixed threshold noise level to determine the QRS endpoint is suggested.     

Maternal Separation in Rats Leads to Anxiety-Like Behavior and a Blunted ACTH Response and Altered Neurotransmitter Levels in Response to a Subsequent Stressor

Adverse early life experiences can have a negative impact on behavior later in life. We subjected rat pups to maternal separation and determined the effect's thereof on adult behavior. We removed rat pups from their mothers for 3 h daily from postnatal days 2 to 14. While controls were reared normally on day 60, the behaviors of the rats were tested using the elevated plus-maze. Some rats were subsequently subjected to restraint stress for a 10-min period. Trunk blood was collected for basal, as well as 15- and 60-min postrestraint stress ACTH determinations. Neurotransmitter levels (noradrenaline (NA), serotonin (5HT), and their metabolites, MHPG and 5HIAA, respectively) were also determined at basal, immediately and 15-min post-restraint stress in the hypothalamus, hippocampus, and frontal cortex in another group of animals. The amount of entries into the arms of the elevated plus-maze was significantly reduced in the separated animals, indicating decreased locomotion. They spent significantly more time in the closed arms of the maze. A significant increase in defecation frequency was noted. These observations suggested anxious behavior. Basal ACTH levels were significantly higher in separated animals. At 15-min post-restraint stress, the ACTH levels were significantly lower than controls, indicating a blunted stress response. A decrease in noradrenaline was noted first in limbic regions and an increase in 5HIAA levels was found in the frontal cortex and hippocampus. We conclude that maternal separation induced abnormal behaviors and stress responses that were associated with altered neurotransmitter levels.     

Diversity and distribution of Maize-associated totivirus strains from Tanzania

Virus Genes - Typically associated with fungal species, members of the viral family Totiviridae have recently been shown to be associated with plants, including important crop species, such as...