CUTANEOUS LEISHMANIASIS INFECTION AMONG PATIENTSIN AL-MADINA AL-MUNAWARAH, KSA

Background: Cutaneous leishmaniosis (CL) is a major tropical infection of public health importance. It is caused by a group of protozoanintracellular parasites.Coinfected individuals with Leishmania-HIV have high risk of having a complete clinical illness and high recurrence rates and mortality. Antiretroviral therapy lowers disease onset, delays relapse, and boosts coinfected patients survival. In Brazil, Ethiopia and the Bihar region in India, high Leishmania-HIV coinfections are recorded.CL is considered as a distinct public health hazard due to the catastrophic effects on the patient. With an estimated yearly average rate of 321,300 cases, in the Middle East and throughout central Asia, CL is endemic. Among the countries of this region, Saudi Arabia has reported an estimated incidence between 9600 and 15,800 cases per year as the fourth endemic focus on zoonotic CL in Afghanistan, Iran and Pakistan. Objective: our present retrospective investigation aims to describe the epidemiology profile of CL in Madinah province. Methods: Human data were collected from the dermatology service of AL-Meqat Hospital. Results: A total of 203 cases of CL confirmed were examined. The seasonal distribution of the phlebotomine fly is followed by cutaneous leishmaniasis. Non-Saudi patients are reported to be more infected with CL (145) than Saudi individuals (58). Conclusion: This study indicates that CL is endemic in Al-Madinah Almonawarah region.CL is a major health problem occur in variable clinical forms.

Linguistic constraints modulate speech timing in an oscillating neural network

Neuronal oscillations putatively track speech in order to optimize sensory processing. However, it is unclear how isochronous brain oscillations can track pseudo-rhythmic speech input. Here we investigate how top-down predictions flowing from internal language models interact with oscillations during speech processing. We show that word-to-word onset delays are shorter when words are spoken in predictable contexts. A computational model including oscillations, feedback, and inhibition is able to track the natural pseudo-rhythmic word-to-word onset differences. As the model processes, it generates temporal phase codes, which are a candidate mechanism for carrying information forward in time in the system. Intriguingly, the model’s response is more rhythmic for non-isochronous compared to isochronous speech when onset times are proportional to predictions from the internal model. These results show that oscillatory tracking of temporal speech dynamics relies not only on the input acoustics, but also on the linguistic constraints flowing from knowledge of language.

Age of Speech Onset in Autism Relates to Structural Connectivity in the Language Network

Speech onset delays (SOD) and language atypicalities are central aspects of the autism spectrum (AS), despite not being included in the categorical diagnosis of AS. Previous studies separating participants according to speech onset history have shown distinct patterns of brain organization and activation in perceptual tasks. One major white matter tract, the arcuate fasciculus (AF), connects the posterior temporal and left frontal language regions. Here, we used anatomical brain imaging to investigate the properties of the AF in adolescent and adult autistic individuals with typical levels of intelligence who differed by age of speech onset. The left AF of the AS group showed a significantly smaller volume than that of the nonautistic group. Such a reduction in volume was only present in the younger group. This result was driven by the autistic group without SOD (SOD−), despite their typical age of speech onset. The autistic group with SOD (SOD+) showed a more typical AF as adults relative to matched controls. This suggests that, along with multiple studies in AS-SOD+ individuals, atypical brain reorganization is observable in the 2 major AS subgroups and that such reorganization applies mostly to the language regions in SOD− and perceptual regions in SOD+ individuals.

Use of radiobiology in medical jurisprudence, with particular reference to delays in diagnosis and therapeutic onset

Objective: This paper considers aspects of radiobiology and cell and tissue kinetics applicable to legal disputations concerned with diagnostic and treatment onset delays. Methods: Various models for tumour volume changes with time are reviewed for estimating volume ranges at earlier times, using ranges of kinetic parameters. Statistical cure probability methods, using Poisson statistics with allowances for parameter heterogeneity, are also described to estimate the significance of treatment delays, as well as biological effective dose (BED) estimations of radiation effectiveness. Results: The use of growth curves, based on parameters in the literature but with extended ranges, can identify a window of earlier times when such tumour volumes would be amenable to a cure based on the literature for curability with stage (and dimensions). Also, where tumour dimensions are not available in a post-operative setting, higher cure probabilities can be achieved if treatment had been given at earlier times. Conclusion: The use of radiobiological modelling can provide useful insights, with quantitative assessments of probable prior conditions and future outcomes, and thus be of assistance to a Court in deciding the most correct judgement. Advances in knowledge: This study collates prior knowledge about aspects of radiobiology that can be useful in the accumulation of sufficient proof within medicolegal claims involving diagnostic and treatment days.

Phase-specific manipulation of neural oscillatory activity by transcranial alternating current stimulation

BackgroundOscillatory phase has been proposed as a key parameter defining the spatiotemporal structure of neural activity. To enhance our understanding of brain rhythms and improve clinical outcomes in pathological conditions, phase-specific modulation of oscillations by transcranial alternating current stimulation (tACS) emerged as a promising approach. However, the effectiveness of tACS in humans is still critically debated.ObjectiveHere, we investigated the phase-specificity of tACS effects on visually evoked steady state responses (SSRs) in 24 healthy human participants of either sex.MethodsTo this end, we used an intermittent electrical stimulation protocol and assessed the influence of tACS on SSR amplitude in the interval immediately following tACS.ResultsWe observed that the phase shift between flicker and tACS modulates evoked SSR amplitudes. The tACS effect size was dependent on the strength of flicker-evoked oscillatory activity, with larger effects in participants showing weaker locking of neural responses to flicker phase. Neural sources of phase-specific effects were localized in the parieto-occipital cortex within flicker-entrained regions. Importantly, the optimal phase shift between flicker and tACS associated with strongest SSRs was correlated with cortical SSR onset delays over the visual cortex.ConclusionsOverall, our data provide electrophysiological evidence for phase-specific modulations of oscillatory activity by tACS in humans. As the optimal timing of tACS application was dependent on neural conduction times as measured by SSR onset delays, data suggest that the interaction between tACS effect and SSR was cortical in nature. These findings corroborate the physiological efficacy of tACS and highlight its potential for controlled modulations of brain signals.

Oscillatory phase shapes syllable perception

The role of oscillatory phase for perceptual and cognitive processes is being increasingly acknowledged. To date, little is known about the direct role of phase in categorical perception. Here we show in two separate experiments that the identification of ambiguous syllables that can either be perceived as /da/ or /ga/ is biased by the underlying oscillatory phase as measured with EEG and sensory entrainment to rhythmic stimuli. The measured phase difference in which perception is biased toward /da/ or /ga/ exactly matched the different temporal onset delays in natural audiovisual speech between mouth movements and speech sounds, which last 80 ms longer for /ga/ than for /da/. These results indicate the functional relationship between prestimulus phase and syllable identification, and signify that the origin of this phase relationship could lie in exposure and subsequent learning of unique audiovisual temporal onset differences.

A neural network model of the effects of entrenchment and memory development on grammatical gender learning

To investigate potential causes of L2 performance deficits that correlate with age of onset, we use a computational model to explore the individual contributions of L1 entrenchment and aspects of memory development. Since development and L1 entrenchment almost invariably coincide, studying them independently is seldom possible in humans. To avoid this confound, we study neural network models that learn to solve gender assignment and agreement tasks in Spanish and French. We model the learner as a collection of recurrent cell assemblies that subserve working memory and are facilitated by trainable long-term connections. Varying the time-course over which assemblies and connections are added allows us to compare small, growing, child-like networks to fixed-size adult-like ones. Networks undergo variable-length exposure to L1 before L2 onset to control the amount of L1 entrenchment. This model, by allowing us independent control of both variables, lends us a novel glimpse of all sides of their interaction and affords a rare test of the less-is-more hypothesis. Network comparisons suggest that final L2 proficiency declines as L2 onset delays increase relative to L1, implicating an L1 entrenchment effect. However, aspects of memory development during learning play a key role in mitigating these impairments, lending support to less-is-more as a contributor to sensitive periods.