3D printed inserts for reproducible high throughput screening of cell migration

Cell migration is a fundamental and complex phenomenon that occurs in normal physiology and in diseases like cancer. Hence, understanding cell migration is very important in the fields of developmental biology and biomedical sciences. Cell migration occurs in 3 dimensions (3D) and involves an interplay of migrating cell(s), neighboring cells, extracellular matrix, and signaling molecules. To understand this phenomenon, most of the currently available techniques still rely on 2-dimensional (2D) cell migration assay, also known as the scratch assay or the wound healing assay. These methods suffer from limited reproducibility in creating a cell-free region (a scratch or a wound). Mechanical/heat related stress to cells is another issue which hampers the applicability of these methods. To tackle these problems, we developed an alternative method based on 3D printed biocompatible cell inserts, for quantifying cell migration in 24-well plates. The inserts were successfully validated via a high throughput assay for following migration of lung cancer cell line (A549 cell line) in the presence of standard cell migration promoters and inhibitors. We also developed an accompanying image analysis pipeline which demonstrated that our method outperforms the state-of-the-art methodologies for assessing the cell migration in terms of reproducibility and simplicity.

Green synthesis of highly stable carbon nanodots and their photocatalytic performance

The present study reports a novel, facile, biosynthesis route for the synthesis of carbon nanodots (CDs) with an approximate quantum yield of 38.5%, using Musk melon extract as a naturally derived-precursor material. The synthesis of CDs was established by using ultraviolet-visible (UV-vis) spectroscopy, Dynamic light scattering, photoluminescence spectroscopy, X-ray diffraction, transmission electron microscopy and Fourier transform infrared (FTIR) spectroscopy. The as-prepared CDs possess an eminent fluorescence under UV-light (λ_ex = 365 nm). The size range of CDs was found to be in the range of 5-10 nm. The authors further explored the use of such biosynthesised CDs as a photocatalyst material for removal of industrial dye. Degradation of methylene blue dye was performed in a photocatalytic reactor and monitored using UV-vis spectroscopy. The CDs show excellent dye degradation capability of 37.08% in 60 min and reaction rate of 0.0032 min^-1. This study shows that synthesised CDs are highly stable in nature, and possess potential application in wastewater treatment.

Lorazepam: an adjuvant therapy in patients with seizure and heliotaxis

Photosensitive epilepsy is a type of reflex epilepsy. Five percent of epileptics are photosensitive, i.e. they show photoconvulsive response (PCR) during intermittent photic stimulation. Patients with photogenic or photosensitive epilepsy have seizures with flickering light. They also exhibit heliotaxis. Sodium valproate and ethosuximide are the common drugs used. Even though benzodiazepines are useful, the specific effect of lorazepam is not mentioned. We report 5 cases of photosensitive epilepsy with inadequate response to usual antiepileptic drugs who had complete or near complete remission with lorazepam.

Role of Q190 of MuLV RT in ddNTP resistance and fidelity of DNA synthesis: a molecular model of interactions with substrates

Gln190 of MuLV reverse transcriptase (RT) plays an important role in the catalytic mechanism of MuLV RT for its conservative and non-conservative mutant derivatives exhibit low catalytic activity. We now report that both Q190N and Q190A MuLV RTs are more efficient in their activity to incorporate ddNTPs and exhibit higher fidelity than the wild-type (WT) enzyme of DNA synthesis in both RNA- and DNA-directed reactions. To obtain some insight into the structural basis for the differential utilization of dNTP and ddNTP by the mutant enzymes, we modeled the binary and the ternary complexes of MuLV RT using corresponding HIV-1 RT structures and available structure of the fragment of MuLV RT. Q190 of MuLV RT appears to be essential for the interaction with 3'OH of dNTP. The lack of a 3'OH moiety in ddNTP does not permit the binding of ddNTPs to WT MuLV RT. However, the shorter side chain of Q190N (or A) mutant MuLV RT and the absence of 3'OH in ddNTP result in the rearrangement of hydrophobic interactions favoring the binding and limited incorporation of ddNTPs. In addition, while modeling the binary and ternary complexes of MuLV RT, we noted that in the formation of the ternary complex, an interaction of Q190 with dNTP substrate requires a shift from its interaction with the template base. This may be achieved by a small conformational change or motion of the loop between beta9 and alphaH containing Q190, which may correspond to the conformational change step requiring participation of Q190 during the catalytic reaction as reported in an earlier biochemical investigation.

First unprovoked seizure--to treat or not to treat?

It has always been a controversial subject whether or not to treat a patient with first episode of seizure. The actual decision whether or not to treat patients who present with initial seizure must be individualized. It depends on probability of having a recurrence and on the perceived risk/benefit ratio of treatment. In a large majority of patients, it is prudent to defer treatment with antiepileptic drugs until a second episode has occurred, unless it is a remote symptomatic seizure, associated with definite epileptiform abnormalities in EEG or a partial seizure. However, in an occasional patient, treatment may be indicated even after a first seizure; for example, in patients involved in certain occupations like driving or operating dangerous machinery.

Dystonia : emerging concepts in pathophysiology

The essential pathophysiological feature of dystonia is co-contraction of antagonistic muscles. This may be due to derangement of the spinal cord or cortical mechanism. In the cord, there is disruption of the normal reciprocal inhibition of antagonists during agonist contraction. This decreased reciprocal inhibition is due to reduced presynaptic inhibition of muscle afferent input to the inhibitory interneuron. The reduced presynaptic inhibition may in turn be either due to defective suprasegmental control or to changes in the tonic afferent input to the interneuron from cutaneous and muscle afferents. Alternatively, genesis of dystonia may entirely be a cortical mechanism. Overactivity of the premotor cortices, which receive projections from basal ganglia via ventral thalamus, could result in dystonia by abnormal activation of cortical motor neurons. This may again be due to a dopaminergic dysfunction of basal ganglia.

Athetosis-dystonia in intramedullary lesions of spinal cord

Athetosis and dystonia are well known clinical signs, described in disorders of basal ganglia. As opposed to pseudoathetosis, true athetosis was hitherto not reported in cord lesions. We here report three patients with athetosis and dystonia of hands due to intramedullary lesions of cervical cord: two patients with syringomyelia and one with glioma. Even though pseudoathetosis can be produced by lesions of posterior columns and likely to be confused with the involuntary movements of our patients, they had clinical and EMG findings consistent with true athetosis. A possible explanation for the athetosis and dystonia due to cord lesion is being postulated.