An anti-Chitinase malaria transmission-blocking single-chain antibody as an effector molecule for creating a Plasmodium falciparum-refractory mosquito

Indirect evidence has suggested the existence of a second chitinase gene, PgCHT2, in the avian malaria parasite Plasmodium gallinaceum. We have now identified PgCHT2 as the orthologue of the P. falciparum chitinase gene PfCHT1, a malaria transmission-blocking target. Computational phylogenetic evidence and biochemical and cell biological functional data support the hypothesis that an avian-related Plasmodium species was the ancestor of both P. falciparum and P. reichenowi, and this single lineage gave rise to another lineage of malaria parasites, including P. vivax, P. knowlesi, P. berghei, P. yoelii, and P. chabaudi. A recombinant PfCHT1/PgCHT2-neutralizing single-chain antibody significantly reduced P. falciparum and P. gallinaceum parasite transmission to mosquitoes. This single-chain antibody is the first anti-P. falciparum effector molecule to be validated for making a malaria transmission-refractory transgenic Anopheles species mosquito. P. gallinaceum is a relevant animal model that facilitates a mechanistic understanding of P. falciparum invasion of the mosquito midgut.     

Cross-Protection of Influenza A Virus Infection by a DNA Aptamer Targeting the PA Endonuclease Domain

Amino acid residues in the N-terminal of the PA subunit (PA_N) of the influenza A virus polymerase play critical roles in endonuclease activity, protein stability, and viral RNA (vRNA) promoter binding. In addition, PA_N is highly conserved among different subtypes of influenza virus, which suggests PA_N to be a desired target in the development of anti-influenza agents. We selected DNA aptamers targeting the intact PA protein or the PA_N domain of an H5N1 virus strain using systematic evolution of ligands by exponential enrichment (SELEX). The binding affinities of selected aptamers were measured, followed by an evaluation of in vitro endonuclease inhibitory activity. Next, the antiviral effects of enriched aptamers against influenza A virus infections were examined. A total of three aptamers targeting PA and six aptamers targeting PA_N were selected. Our data demonstrated that all three PA-selected aptamers neither inhibited endonuclease activity nor exhibited antiviral efficacy, whereas four of the six PA_N-selected aptamers inhibited both endonuclease activity and H5N1 virus infection. Among the four effective aptamers, one exhibited cross-protection against infections of H1N1, H5N1, H7N7, and H7N9 influenza viruses, with a 50% inhibitory concentration (IC₅₀) of around 10 nM. Notably, this aptamer was identified at the 5th round but disappeared after the 10th round of selection, suggesting that the identification and evaluation of aptamers at early rounds of selection may be highly helpful for screening effective aptamers. Overall, our study provides novel insights for screening and developing effective aptamers for use as anti-influenza drugs.     

Screw-worm myiasis of prolapsed rectum

Background

Wound myiasis in the Indian subcontinent is most commonly caused by old world screw-worm (Chrysomya bezziana).

Case Report and management

A 4-yearold malnourished girl presented with full thickness rectal prolapse following acute diarrhea with a large wound and screwworm myiasis of the rectum. Turpentine oil was applied to immobilize the maggots followed by manual extraction. Prolapse was successfully treated by manual reduction followed by strapping of the buttocks.

Outcome

Child was thriving well and gained 2 kg weight in follow up after two weeks.

Message

Parents should be educated about taking care of prolapsed rectum.     

Markedly asymmetric presentation in multiple system atrophy

BackgroundMultiple system atrophy (MSA) presents with fairly symmetrical, levodopa unresponsive parkinsonism and additional features like autonomic dysfunction, cerebellar and corticospinal tract involvement. Marked asymmetry in atypical parkinsonism suggests alternative diagnosis like Corticobasal syndrome (CBS).MethodsWe describe five unusual cases, who presented initially with markedly asymmetric parkinsonism, rigid dystonic abnormal limb posturing and subsequently developed clinical and/or radiological features consistent with probable MSA-P.ResultsUsing the internationally accepted diagnostic criteria, the patients fulfilled the diagnostic criteria for probable MSA-P after 5 years from disease onset. Case 4 and 5 had characteristic MRI features and Case 2 was pathologically confirmed.ConclusionsWe use these cases to highlight that MSA-P MSA-P can present rarely with very marked asymmetry, dystonic limb and myoclonic jerks leading to a diagnosis of CBS at onset.     

Resveratrol,Wine, and Atherosclerosis

This review emphasizes the effects of resveratrol on factors involved in the mechanism of atherosclerosis and risk factors for atherosclerosis. The effects of wine and resveratrol on atherosclerosis are also discussed. Resveratrol is a potent antioxidant and an anti-inflammatory agent. It reduces the expression of cell adhesion molecules, monocyte colony stimulating factors, matrix metalloproteinases, and growth factors; and inhibits platelet aggregation and vascular smooth muscle cell proliferation. It reduces the serum levels of total cholesterol, triglycerides (TG), and raises high-density lipoprotein cholesterol, inhibits expression of C-reactive protein and lowers the levels of advanced glycation end products and its receptor in the vascular tissue. It lowers the risk factors for plaque rupture. Epidemiological data show that moderate consumption of alcohol has an inverse association with carotid atherosclerosis while high consumption has a positive association with carotid atherosclerosis. Wine reduces the extent of atherosclerosis in animal model. The antiatherosclerotic effect of wine is mainly due to it resveratrol content. Resveratrol reduces the extent of atherosclerosis in animal model of atherosclerosis (apolipoprotein [Apo] E-deficient and Apo E^−/−/low-density lipoprotein receptor-deficient mice and macrophage). In rabbit model of atherosclerosis, both reduction and acceleration of atherosclerosis have been reported with resveratrol. There are no data for regression and slowing of progression of atherosclerosis. Robust clinical trials for suppression of atherosclerosis are lacking. In conclusion, resveratrol has potential but experimental studies in depth and robust clinical trials are lacking for this agent to be of any value in the primary and secondary prevention of coronary and peripheral artery disease.     

Patients with rest-tremor and scans with ipsilateral dopaminergic deficit

Dopamine transporter imaging is typically abnormal in Parkinson’s disease and shows reduced striatal uptake, which is typically greater contralateral to the clinically more affected side. However, tremor-dominant Parkinson’s disease patients may have significantly lower uptake in the striatum ipsilateral to the rest-tremor compared to akinetic-rigid PD patients, implying a possible role of an ipsilateral deficit in the generation of rest-tremor.We report here three patients with rest-tremor and the unexpected finding of an ipsilateral presynaptic dopaminergic deficit with normal uptake contralateral to the rest-tremor in dopamine transporter imaging. We divided them in two groups, with and without a corresponding structural lesion in brain imaging. These data may suggest a role of ipsilateral dopaminergic deficit in the generation of rest-tremor. An explanation of these findings could be damage of crossed dopaminergic fibres from the substantia nigra to thalamus, which can cause motor impairment ipsilateral to dopamine depletion experimentally. This is speculative but there is no doubt that these cases exist and we encourage others to report similar cases, as this may assist in the better understanding of the yet unknown pathophysiology of rest-tremor.     

Defining the Epsilon‐Sarcoglycan (SGCE) Gene Phenotypic Signature in Myoclonus‐Dystonia: A Reappraisal of Genetic Testing Criteria

Mutations or exon deletions of the epsilon‐sarcoglycan (SGCE) gene cause myoclonus‐dystonia (M‐D), but a subset of M‐D patients are mutation‐negative and the sensitivity and specificity of current genetic testing criteria are unknown. We screened 46 newly enrolled M‐D patients for SGCE mutations and deletions; moreover, 24 subjects previously testing negative for SGCE mutations underwent gene dosage analysis. In our combined cohorts, we calculated sensitivity, specificity, positive and negative predictive values, and area under the curve of 2 published sets of M‐D diagnostic criteria. A stepwise logistic regression was used to assess which patients' characteristics best discriminated mutation carriers and to calculate a new mutation predictive score (“new score”), which we validated in previously published cohorts. Nine of 46 (19.5%) patients of the new cohort carried SCGE mutations, including 5 novel point mutations and 1 whole‐gene deletion; in the old cohort, 1 patient with a complex phenotype carried a 5.9‐Mb deletion encompassing SGCE. Current diagnostic criteria had a poor ability to discriminate SGCE‐positive from SGCE‐negative patients in our cohort; conversely, age of onset, especially if associated with psychiatric features (as included in the new score), showed the best discriminatory power to individuate SGCE mutation carriers, both in our cohort and in the validation cohort. Our results suggest that young age at onset of motor symptoms, especially in association with psychiatric disturbance, are strongly predictive for SGCE positivity. We suggest performing gene dosage analysis by multiple ligation‐dependent probe amplification (MLPA) to individuate large SGCE deletions that can be responsible for complex phenotypes. © 2013 Movement Disorder Society     

Failure of explicit movement control in patients with functional motor symptoms

Functional neurological symptoms are one of the most common conditions observed in neurological practice, but understanding of their underlying neurobiology is poor. Historic psychological models, based on the concept of conversion of emotional trauma into physical symptoms, have not been implemented neurobiologically, and are not generally supported by epidemiological studies. In contrast, there are robust clinical procedures that positively distinguish between organic and functional motor signs that rely primarily on distracting attention away from movement or accessing it covertly. We aimed to investigate the neurobiological principles underpinning these techniques and implications for understanding functional symptoms. We assessed 11 patients with functional motor symptoms and 11 healthy controls in three experimental set‐ups, where voluntary movements were made either with full explicit control or could additionally be influenced automatically by factors of which participants were much less aware (one‐back reaching, visuomotor transformation, and precued reaction time with variable predictive value of the precue). Patients specifically failed in those tasks where preplanning of movement could occur and under conditions of increasing certainty regarding the movement to be performed. However, they implicitly learned to adapt to a visuomotor transformation as well as healthy controls. We propose that when the movement to be performed can be preplanned or is highly predicted, patients with functional motor symptoms shift to an explicit attentive mode of processing that impairs kinematics of movement control, but movement becomes normal when such processes cannot be employed (e.g., during unexpected movement or implicit motor adaptation). © 2013 Movement Disorder Society