First Report of Verticillium Wilt Caused by Verticillium nonalfalfae on Tree-of-Heaven (Ailanthus altissima) in Ohio.

Verticillium wilt of the highly invasive tree-of-heaven [Ailanthus altissima (Mill.) Swingle], caused by Verticillium nonalfalfae Interbitzin et al. (1), formerly classified as V. albo-atrum Reinke and Berthold, has been reported in the United States from two states: Pennsylvania (2) and Virginia (3). Infected A. altissima in both states exhibited similar symptoms of wilt, premature defoliation, terminal dieback, yellow vascular discoloration, and mortality. In June 2012, the second author observed dead and dying A. altissima trees in southern Ohio (Pike County) that exhibited symptoms similar to those on diseased A. altissima trees in Pennsylvania and Virginia. Samples were collected from stems of three symptomatic A. altissima trees and sent to Penn State for morphological and molecular identification. Immediately upon arrival, samples were surface-disinfected and plated onto plum extract agar (PEA), a semi-selective medium for Verticillium spp., amended with neomycin and streptomycin (2). The samples yielded six isolates, two from each of the three symptomatic trees, all of which were putatively identified as V. nonalfalfae based on the presence of verticillate conidiophores and formation of melanized hyphae. DNA was extracted from three isolates and molecular analyses performed using known primers (1) coding for elongation factor 1-alpha (EF), glyceraldehyde-3-phosphate dehydrogenase (GPD), and tryptophan synthase (TS). A BLAST search generated sequences that revealed 100% similarity to V. nonalfalfae for all three protein coding genes among the three Ohio isolates and reference sequences from Ailanthus, including isolates VnAaPA140 (GenBank Accession Nos. KC307764, KC307766, and KC307768) and VnAaVA2 (KC307758, KC307759, and KC307760), as well as isolate PD592 from potato (JN188227, JN188163, and JN188035), thereby confirming taxonomic placement of the Ohio Ailanthus isolates among those recovered from Ailanthus in Pennsylvania and Virginia. Aligned sequences from one representative isolate, VnAaOH1, were deposited into GenBank as accessions KC307761 (EF), KC307762 (GPD), and KC307763 (TS). In August 2012, the pathogenicity of all six isolates was confirmed by root-dipping 10 healthy 3-week-old A. altissima seedlings (seeds collected in University Park, PA) into conidial suspensions of 1 × 107 cfu/ml, wherein all inoculated seedlings wilted and died within 4 and 9 weeks, respectively. V. nonalfalfae was reisolated from all inoculated seedlings; control seedlings inoculated with distilled water remained asymptomatic. Ohio is the third state from which V. nonalfalfae has been reported to be pathogenic on A. altissima. If V. nonalfalfae proves to be widespread, it may represent a natural biocontrol for the invasive A. altissima. Also, since USDA APHIS evaluates and regulates new potential biocontrol agents on a state-by-state basis, it is important to document each state in which V. nonalfalfae is killing A. altissima, so that in-state inoculum can be used for biocontrol efforts, simplifying the regulatory process. References: (1) P. Inderbitzin et al. 2011 PLoS ONE, 6, e28341, 2011. (2) M. J. Schall and D. D. Davis. Plant Dis. 93:747, 2009. (3) A. L. Snyder et al. Plant Dis. 96:837, 2013.

Immunocytochemical localization of opsin, visual arrestin, myosin III, and calmodulin in Limulus lateral eye retinular cells and ventral photoreceptors.

The photoreceptors of the horseshoe crab Limulus polyphemus are classical preparations for studies of the photoresponse and its modulation by circadian clocks. An extensive literature details their physiology and ultrastructure, but relatively little is known about their biochemical organization largely because of a lack of antibodies specific for Limulus photoreceptor proteins. We developed antibodies directed against Limulus opsin, visual arrestin, and myosin III, and we have used them to examine the distributions of these proteins in the Limulus visual system. We also used a commercial antibody to examine the distribution of calmodulin in Limulus photoreceptors. Fixed frozen sections of lateral eye were examined with conventional fluorescence microscopy; ventral photoreceptors were studied with confocal microscopy. Opsin, visual arrestin, myosin III, and calmodulin are all concentrated at the photosensitive rhabdomeral membrane, which is consistent with their participation in the photoresponse. Opsin and visual arrestin, but not myosin III or calmodulin, are also concentrated in extra-rhabdomeral vesicles thought to contain internalized rhabdomeral membrane. In addition, visual arrestin and myosin III were found widely distributed in the cytosol of photoreceptors, suggesting that they have functions in addition to their roles in phototransduction. Our results both clarify and raise new questions about the functions of opsin, visual arrestin, myosin III, and calmodulin in photoreceptors and set the stage for future studies of the impact of light and clock signals on the structure and function of photoreceptors.

Effect of methylphenidate on attention in children with attention deficit hyperactivity disorder (ADHD): ERP evidence.

Methylphenidate is the most common treatment for attention deficit hyperactivity disorder (ADHD) and has been shown to improve attention and behaviour. However, the precise nature of methylphenidate on specific aspects of attention at different dose levels remains unclear. We studied methylphenidate effects in ADHD from a neurophysiological perspective, recording event-related potentials (ERPs) during attention task performance in normal controls and children with ADHD under different dose conditions. Twenty children with ADHD and 20 age matched controls were assessed with a continuous performance task requiring subjects to identify repeating alphabetic characters. ERPs and behavioural measures were recorded and analyzed for trials where a correct response was made. The ADHD group was assessed off drug (baseline) and on placebo, low (0.28 mg/kg) and high (0.56 mg/kg) dose levels of methylphenidate. The results showed that the ADHD group at baseline was more impulsive and inattentive than controls and had shorter P2 and N2 latencies and longer P3 latencies. Low dose methylphenidate was associated with reduced impulsivity (fewer false alarms) and decreased P3 latencies, whereas the higher dose level was associated with reduced impulsivity and less inattention (more hits), as well as increased P2 and N2 latencies and decreased P3 latencies. Amplitudes were unaffected and there were no adverse effects of the higher dose for any of the children. These results suggest differential dosage effects and a dissociation between dose levels and aspects of processing.

HIV-positive women over fifty: how they cope.

Healthcare providers may not understand the special issues and needs of older persons with HIV. This article directs particular attention to the unique reactions of older women to an HIV-positive diagnosis. Through their participation in a support group, some older HIV-positive women have been able to adapt to their illness with a variety of coping styles. Illustrations of the ways these women meet challenges both individually and as a group are presented. The article concludes with simple messages from the women to the members of the medical community.

Effects of methylphenidate in children with attention deficit hyperactivity disorder: a comparison of event-related potentials between medication responders and non-responders.

Event-related potentials (ERPs) were compared among three groups, each with 13 subjects: (1) ADHD non-responders to methylphenidate treatment; (2) ADHD responders to methylphenidate treatment; and (3) normal control children. Response to methylphenidate was determined through extensive psychoeducational and cognitive assessments during a 4-week double-blind medication assessment. ERPs were recorded each week from 13 active electrodes during a visual feature detection task and a semantic classification task. Significant group effects were found for N2 and P3b latencies due to longer latencies for the ADHD children. Off medication, there were no differences between responders and non-responders. However, on methylphenidate non-responders had significantly longer P3b latencies than responders. Cognitive testing also revealed differential performance on medication between non-responders and responders on the paired-associate learning (PAL) task. Thus, both cognitive and ERP measures were found to differentiate ADHD non-responders and responders to methylphenidate treatment.

In vitro optimisation of a microdialysis system with potential for on-line monitoring of lactate and glucose in biological samples.

The optimisation and evaluation of the microdialysis component of a prototype miniaturised total analysis system for application in the continuous monitoring of lactate and glucose is reported. The complete unit comprises a high efficiency microdialysis sampling system, a miniaturised microflow manifold with an integrated biosensor array, together with the hardware and software necessary for controlling the flow parameters and monitoring the sensor signals. Sampling occurs via a microdialysis shunt probe which is perfused continuously with a physiological buffered saline solution. The continuous dialysate outflow is presented to the biosensor array, resulting in the appropriate amperometric signals. Aspects of technological significance addressed here include probe membrane size, perfusate flow rate, sample flow rate, temperature change, probe sterilisation procedures, and heparin content of the physiological saline solution employed.

Methylphenidate slows right hemisphere processing in children with attention-deficit/hyperactivity disorder.

To examine the effects and particularly, any potential detrimental effects of methylphenidate on right hemisphere processing in children with attention-deficit/hyperactivity disorder (ADHD), the performance of 26 children (aged 8-15 years) with ADHD was compared under methylphenidate and placebo on various cognitive tasks in a double-blind within-subjects design. Results indicated that reaction times on a tachistoscopic task were slower on methylphenidate for stimuli that produced a left visual field advantage (reflecting better right hemisphere functioning) but not for stimuli that produced a right visual field advantage (reflecting better left hemisphere functioning) or for bilateral stimuli. It is argued that methylphenidate induces a slower response on tasks involving right hemisphere processing, resulting in slower reaction times and unchanged accuracy rates. Findings on two tasks that more closely reflect classroom-type tasks revealed an improvement in performance on methylphenidate, suggesting that any stimulant-induced benefits on learning style may have overcome detrimental effects on unilateral processing. These findings may help understand the complex, diverse, and sometimes unpredictable effects of psychostimulants on cognitive functioning that are observed clinically in individuals treated for ADHD.

Hemispheric processing and methylphenidate effects in attention-deficit hyperactivity disorder.

To advance our understanding of attention-deficit hyperactivity disorder and medication effects we draw upon the evidence for (1) a neurotransmitter imbalance between norepinephrine and dopamine in attention-deficit hyperactivity disorder and (2) an asymmetric neural control system that links the dopaminergic pathways to left hemispheric processing and links the noradrenergic pathways to right hemispheric processing. It appears that attention-deficit hyperactivity disorder may involve a bihemispheric dysfunction characterized by reduced dopaminergic and excessive noradrenergic functioning. In turn, favorable medication effects may be mediated by a restoration in neurotransmitter balance and by increased control over the allocation of attentional resources between hemispheres.

Phase-selective AC adsorptive stripping voltammetric assay for aminopterin and 10-Edam in human serum.

Aminopterin was studied as a model compound for its analogues which maintain the pteridine ring in their structure. Its adsorptive behaviour on mercury was studied and the DC adsorptive stripping and phase-selective AC adsorptive stripping conditions were optimized. 10-Edam, an aminopterin analogue, was studied and shown to behave similarly to aminopterin. Phase-selective AC voltammetry provided the best signal and gave a detection limit of 4 x 10(-12) M aminopterin in aqueous solution employing an accumulation time of 10 min. The optimized method was applied to the analysis of both aminopterin and 10-Edam respectively in human serum. After extraction with a C18 reversed-phase cartridge the detection limit of the method was 1 x 10(-8) M aminopterin and the overall assay percentage recovery was 73.5% (n = 5) at a concentration of 5 x 10(-7) M aminopterin in serum. The analysis of 10-Edam at the same concentration in serum yielded the higher percentage recovery of 94.46% (n = 5) following the same procedure.

Changes in event-related potentials with stimulant medication in children with attention deficit hyperactivity disorder.

Thirty-two children with attention deficit hyperactivity disorder (ADHD) undergoing a 4 week double-blind medication assessment (methylphenidate) and 32 normal controls were studied using event-related potentials (ERPs). The ERPs were recorded from 13 active electrodes during a visual feature detection task. Significant age effects were found in N2, P3a and P3b latencies, that did not interact with group. The P3a and P3b latencies were significantly longer in the ADHD children on baseline testing; there were no latency differences between the groups of children when the normal controls were compared with the ADHD children on their optimal drug dosage (as determined by extensive behavioural and cognitive assessments). There were no significant distributional effects either between groups, or with the ADHD children as a function of medication; there were also no significant differences in reaction time measures. Thus, only the ERPs reflected slowed processing in the ADHD children that normalized on appropriate medication.

Effects of methylphenidate on impulsive responding in children with attention-deficit hyperactivity disorder.

The present investigation examined the effects of methylphenidate on impulsivity in children with attention-deficit hyperactivity disorder (ADHD). A task was designed to measure empirically the ADHD child's proclivity to blurt out incorrect answers before giving a final and/or correct response. Twenty-six ADHD children referred for double-blind placebo-controlled assessment of medication responsiveness and 14 non-ADHD controls were given a visual search word-matching task to assess impulsive responding. An analysis of covariance showed that ADHD children on methylphenidate made fewer impulsive errors than ADHD children on placebo. The control group made fewer impulsive errors than the ADHD children in the placebo condition, but the performance of the ADHD children on medication approximated the performance of the children without ADHD. These preliminary findings suggest that the word-matching task may be a useful tool for assessing impulsive responding and determining the benefits of stimulant medication on impulsivity.

Molecular and particulate depositions for regional myocardial flows in sheep.

The deposition of microspheres in small tissue regions is not strictly flow dependent. In comparison with the soluble flow marker 2-iododesmethylimipramine (IDMI), deposition of 16.5-microns microspheres was mildly but systematically biased into high flow regions of rabbit hearts (Bassingthwaighte JB, Malone MA, Moffett T-C, King RB, Little SE, Link JM, Krohn KA. Am J Physiol 1987;253 (Heart Circ Physiol 22):H184-H193). To examine the possibility of bias in larger hearts, a similar study was undertaken in sheep. 141Ce- and 103Ru-labeled 16.5-microns microspheres in one syringe and 125I- and 131I-DMI in another syringe were injected simultaneously into the left atrium of five open-chest sheep while obtaining reference blood samples from the femoral artery. In six other sheep, one microsphere type and one IDMI were used. Hearts were removed 1 minute after injection, cut into approximately 254 pieces averaging 217 mg, and regional deposition densities calculated for each tracer from the isotopic counts. Correlations in the five animals between the two differently labeled IDMIs and between the two microspheres were both greater than or equal to 0.98. In all 11 sheep, scatter plots of microsphere deposition densities versus IDMI densities showed that differences between microspheres and IDMI had substantially more scatter (0.84 less than r less than 0.98) but were not random. Microsphere depositions tended to be lower than IDMI depositions in low flow regions and higher in high flow regions, in accord with the expected bias that at a bifurcation a microsphere is most likely to enter the branch with higher flow. There was less bias ascribable to endomyocardial/epicardial maldistribution. Thus, while microsphere depositions appear to err systematically with respect to flow when the regions of interest are small enough that the diameters of their arterioles are only a few times those of the microspheres, microspheres are, in sheep as in rabbits, adequate for estimating regional flows.

Cell specific enzyme markers as indicators of neurotoxicity: effects of acute exposure to methylmercury.

In order to assess the sensitivity of several cell specific enzyme markers (tyrosine hydroxylase (TH), glutamic acid decarboxylase, choline acetyltransferase, glutamine synthetase (GS), neuron specific and non-neuronal enolase and 2',3'-cyclic nucleotide phosphohydrolase (CNP] as indices of neurotoxicity, changes in their activities were monitored after rats were treated with two doses of the neurotoxic agent, methylmercury chloride (MMC). Comparisons were also made of any histopathological changes occurring in the tissues examined. At the low dose rate (3.36 mg Hg/kg, po, for 14 days), the rats exhibited less body weight gain compared to untreated animals. No change in either the neuronal or noneuronal enzyme markers was observed in brain but a significant increase in the myelin marker, CNP, and total enolase activity was seen in the optic nerve. Morphological evaluation by light microscopy indicated no discernible neuronal lesions in MMC-exposed animals. At the higher MMC dose (7.05 mg Hg/kg, po, for 7 days), there was about a 20% loss in the body weight of treated animals and partial hind limb paralysis was observed. Of all the neuronal marker enzymes examined, only TH was found to be decreased in the striatum. The proliferating astroglial marker, GS, was elevated only in the cerebellum. CNP was found to be decreased in both the optic and sciatic nerve. As in the lower dose group no pathological changes were observed at the light microscopic level in the brain of MMC-treated rats. These data suggest that of the cell specific marker enzymes studied, GS in the cerebellum and TH in the striatum may be useful biochemical markers for the neurotoxic action of MMC.

The effects of methylphenidate on levels of processing and laterality in children with attention deficit disorder.

Effects of stimulant medication (methylphenidate) on levels (feature, name, semantic) of word processing by the left and right hemisphere were assessed in 31 attention-deficit-disordered children. In a double-blind procedure, same-different decisions were made to tachistoscopically presented word pairs under medication and placebo. Analysis of manual response times failed to show any negative effects of medication. Feature decisions were faster than name decisions, which were faster than semantic decisions. Methylphenidate induced a right visual field advantage (left hemisphere) for the name decision, which was interpreted as a normalization effect. The results suggest that (1) methylphenidate may selectively improve the phonological level of word processing and (2) methylphenidate's favorable therapeutic effect is produced through inhibition of excessive right hemisphere activity in response to task demands that engage the left hemisphere.

Validity of microsphere depositions for regional myocardial flows.

Due to the particulate nature of microspheres, their deposition in small-tissue regions may not be strictly flow dependent. To evaluate the importance of rheological and geometric factors and random error, their deposition densities in small regions of rabbit hearts were examined in comparison with those of a new "molecular microsphere," 2-iododesmethylimipramine (IDMI), whose high lipid solubility allows it to be delivered into tissue in proportion to flow, and whose binding in tissue prevents rapid washout. 141Ce- and 103Ru-labeled 16.5-micron spheres in one syringe and [125I]- and [131I]DMI in another syringe were injected simultaneously into the left atrium of open-chest rabbits, while obtaining reference blood samples from the femoral artery. Hearts were removed 1 min after injection, cut into approximately 100 pieces averaging 54 mg, and the regional deposition densities calculated for each tracer from the isotopic counts. Correlations between the differently labeled microspheres were r greater than 0.95 and for the two IDMIs were greater than 0.98. Scatter plots of sphere densities vs. IDMI densities showed that differences between microspheres and IDMI had substantial scatter, 0.87 less than r less than 0.96 and were not random. Microsphere depositions tended to be lower than IDMI depositions at low flows and higher at high flows. The tendency for spheres to be deposited preferentially in high-flow regions may be explained by a bias at bifurcations toward entering the branch with higher flow and secondarily toward entering those branches that are straighter. We conclude that microspheres are generally adequate for estimating regional flows but suffer systematic error when the regions of interest are supplied via arteries of diameters only a few times those of the microspheres.

Central projections of identified Drosophila sensory neurons in relation to their time of development.

Eight sensory structures (campaniform sensilla), appearing identical in the light and scanning electron microscopes, are found in specific locations on the wings of Drosophila. Their axons enter one of 2 central tracts, a medial one or a lateral one. The topographic arrangement of the sensilla on the wing is not reflected in this central projection pattern. There is, however, a strict correlation between the time when a sensillum develops and the path its axon follows: The 4 sensilla whose axons form the medial projection are born and differentiate early during the development of the wing, while the other 4 sensilla, all of which project laterally, arise during a second wave of differentiation. This time-related projection pattern remains stable in the face of a variety of genetically induced alterations in the precise number and location of sensilla.

Cochlear prostheses: stimulation-induced damage.

The effects of 4 weekly, three-hour exposures to continuous sinusoidal (l kHz) electrical stimulation of the inner ear at various current levels were assessed in the chronically implanted guinea pig. With scala tympani stimulation, histopathological damage, including new bone growth, was observed for currents at and above 100 microA rms. No changes were observed in similarly implanted, but not stimulated cochleas. At equal current levels, less damage was found in subjects stimulated via electrodes placed on the round window and promontory, as compared to the scala tympani. Consistent reversible changes in threshold and suprathreshold features of the electrically evoked auditory brainstem response (EABR) were found. The magnitude of EABR change was directly related to exposure stimulus current level and to cochlear stimulation site. Suprathreshold features of the EABR were more sensitive to continuous stimulation exposures than threshold measures. Reversible EABR changes were found in the presence and absence of stimulation-induced histopathology.