January 2012: This Month in JoVE

The Journal of Visualized Experiments (JoVE) begins 2012 by publishing its 1500th article, which focuses on a method for analyzing the free radical composition of cigarette smoke. Although tobacco tar is thought to be the most carcinogenic agent in cigarette smoke, free radicals are well known cancer-causing molecules, and the level of these carcinogens contained in cigarette smoke is not currently known. The method employed in this article combines the use of a single-port smoking device, which simulates cigarette puffing, with electron spin resonance (ESR) spectroscopy, a technique, which measures the spin energy emitted by the unpaired electrons in free radicals. One important modification of the single port smoking device used in this article, is the introduction of a liquid nitrogen trap in front of the spin trap. Liquid nitrogen removes water vapor from cigarette smoke and greatly improves ESR spectra as a result.

In addition to measuring the free radical concentration found in cigarette smoke, plant antioxidants are introduced into modified cigarette filters and the ESR spectra of cigarette smoke passed through these filters is obtained. Grape seed extract and lycopene were observed to have the most significant scavenging effects on free radicals, and if cost effective means of including these molecules into cigarette filters can be developed, a less harmful cigarette could be created.

In Clinical and Translational Medicine, JoVE presents an analytical method for determining the local Gyrification Index (lGI) – a measurement of the extent of cortical folding. Cortical folds develop during the first few post natal months, and adverse events during this time can lead to abnormalities in the brain’s surface anatomy, which may ultimately correlate with neuropsychiatric disorders.

The analysis tool developed for calculating the local Gyrification Index is Freesurfer, which can convert T1 weighted MRI scans into 3D reconstructions of the cortex. Separate reconstructions are created for the grey/white mater and grey/pial interfaces, which are manually adjusted before computating the lGI. Following a smoothing operation, circular regions of the pial and grey/white surfaces are compared, in order to compute the lGI for thousands of points over the entire brain. Freesurfer makes analysis of gyrification straightforward and accessible to clinicians and brain scientists, who are interested in comparing the extent of cortical folding between different individuals in normal and disease states.

JoVE’s Immunology and Infection article for the month of January continues the journal’s tradition of publishing cutting edge methodology in vector born disease research. Specifically, this article adds to JoVE’s comprehensive collection of protocols for malaria research by extending our library to cerebral malaria – a devastating condition with high susceptibility in children. Briefly, this protocol involves exposing a monolayer of human brain endothelial cells, passaged onto petri dishes, to Plasmodium falciparum-infected red blood cells. Following washing and enriching steps, high yields of parasites, which carry the potential to infect the brain, can be isolated and further characterized.

In Neuroscience, JoVE showcases a method for studying the migration of neural crest cells. These cells are a transient, multipotent, developmental cell type that can, in addition to becoming neuronal tissue, differentiate into smooth muscle, chromaffin cells, cartiliage, and bone. Chick embryos are carefully prepared, so that the trunk region can be isolated and the neural tube excised for overnight culture on fibronectin-coated coverslips, which allows neural crest cells to emigrate from the neural tube. Following removal of the neural tube, coverslips containing the cultured neural crest cells are transferred to a modified Zigmond chamber – a chamber which enables a concentration gradient of putative chemotactic agent to be established across the culture. Timelapes imaging followed by analysis of cell trajectories, is used to assess the chemotactic potential of molecules loaded into the zigmund chamber, providing insight into the molecular cues that guide migration of this important developmental cell type.

These featured articles comprise four of fifty video-protocols for release in January. Other notable articles include methods for visualizing the cuticle structures of c. elegans, thermal imaging of delayed onset muscle soreness, culturing the ventral midbrain in organotypic slices, and inducing atherosclerosis in mice.