The role of the cerebellum in the pathogenesis of cortical myoclonus

The putative involvement of the cerebellum in the pathogenesis of cortical myoclonic syndromes has been long hypothesized, as neuropathological changes in patients with cortical myoclonus have most commonly been found in the cerebellum rather than in the suspected culprit, the primary somatosensory cortex. A model of increased cortical excitability due to loss of cerebellar inhibitory control via cerebello‐thalamo‐cortical connections has been proposed, but evidence remains equivocal. Here, we explore this hypothesis by examining syndromes that present with cortical myoclonus and ataxia. We first describe common clinical characteristics and underlying neuropathology. We critically view information on cerebellar physiology with regard to motorcortical output and compare findings between hypothesized and reported neurophysiological changes in conditions with cortical myoclonus and ataxia. We synthesize knowledge and focus on neurochemical changes in these conditions. Finally, we propose that the combination of alterations in inhibitory neurotransmission and the presence of cerebellar pathology are important elements in the pathogenesis of cortical myoclonus. © 2014 Movement Disorder Society     

Hypertension and its severity in children with steroid sensitive nephrotic syndrome during remission

Background and objective

Hypertension is not a typical feature of steroid sensitive nephrotic syndrome (SSNS) and the presence of persistent hypertension is suggestive of significant renal lesion. There is paucity of data regarding occurrence and severity of hypertension in SSNS in pediatric population during remission and was the main objective of this study. In addition, correlation with factors like family history, BMI, and lipid profile was studied.

Methods

Cross-sectional study conducted at tertiary care center in India including 81 children of infrequent relapsing SSNS between 1 and 10 years in remission and was off steroids. Grading and severity of hypertension were assessed. Statistical analysis was done using SPSS version 21.0.

Results

Median age of presentation was 5 years, with male:female ratio of 1.3:1. Out of 81 infrequent relapsing SSNS children, 23.45% (19) had hypertension. Among those children with hypertension (n?=?19), 73.68% (14) had positive family history compared to 32.25% (20) in those without hypertension. Positive correlation was found between BP and serum cholesterol and LDL. Of the hypertensive patients, 1 (5.26%) had fundus changes, 2 (10.52%) had features of left ventricular hypertrophy, and 13 (68.42%) had non-nephrotic range proteinuria.

Conclusion

There is high incidence of hypertension in NS children during remission. Though significant positive correlation was found with positive family history of hypertension and deranged lipid profile highlighting possibility of essential hypertension in them, there is need for close active monitoring and management of hypertension in them as untreated cases may have significant target organ damage.

     

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.     

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.     

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.