Microfluidic System for Controlled Gelation of a Thermally Reversible Hydrogel.

Microfluidic system for controlled gelation of a thermally reversible hydrogel.

IEEE Trans Biomed Circuits Syst. 2009 Aug; 3(4): 195-201
Flueckiger J, Cheung KC

The integration of cell culture and characterization onto a miniaturized platform promises to benefit many applications such as tissue engineering, drug screening, and those involving small, precious cell populations. This paper presents the controlled on-chip gelation of a thermally-reversible hydrogel. Channel design and flowrate control are crucial in determining hydrogel geometry, while integrated temperature control triggers reversible gel formation. Formation of hydrogel droplets through shearing of immiscible flows is demonstrated with subsequent on-chip gelation. The temperature of phase transition occurs between 32degC-34degC, well within the range for mammalian cell encapsulation and culture. HubMed – drug

Physical presence of nor-binaltorphimine in mouse brain over 21 days after a single administration corresponds to its long-lasting antagonistic effect on kappa opioid receptors.

J Pharmacol Exp Ther. 2013 Jul 12;
Patkar KA, Wu J, Ganno ML, Singh HD, Ross NC, Rasakham K, Toll L, McLaughlin JP

In the mouse 55°C warm-water tail-withdrawal assay, a single administration of nor-BNI (10 mg/kg, i.p.) antagonized kappa opioid receptor (KOR) agonist-induced antinociception up to 14 days, whereas naloxone (10 mg/kg, i.p.) mediated antagonism lasted less than a day. In saturation binding experiments, mouse brain membranes isolated and washed 1 or 7, but not 14 days after nor-BNI administration demonstrated a significant time dependent decrease in maximal KOR agonist [(3)H]U69,593 binding. To determine whether brain concentrations of nor-BNI were sufficient to explain the antagonism of KOR-mediated antinociception, mouse blood and perfused brain were harvested at time points ranging from 30 min to 21 days after a single administration and analyzed for the presence of nor-BNI using LC-MS/MS. Nor-BNI was detected in the perfused brain homogenate up to 21 days after administration (30 nmol, i.c.v. or 10 mg/kg, i.p.). Subsequent experiments in which nor-BNI was administered at doses estimated from the amounts detected in the brain homogenates isolated from pretreated mice over time demonstrated significant antagonism of U50,488 antinociception in a manner consistent with the magnitude of observed KOR antagonism. The dose (1.4 nmol) approximating the lowest amount of nor-BNI detected in brain on day 14 did not antagonize U50,488-induced antinociception, consistent with the absence of U50,488 antagonism observed in vivo at this time point after pre-treatment. Overall, the physical presence of nor-BNI in the mouse brain paralleled its in vivo pharmacological profile, suggesting physico-chemical and pharmacokinetic properties of nor-BNI may contribute to the prolonged KOR antagonism. HubMed – drug

Stereo-EEG-guided radio-frequency thermocoagulations of epileptogenic grey-matter nodular heterotopy.

J Neurol Neurosurg Psychiatry. 2013 Jul 13;
Cossu M, Fuschillo D, Cardinale F, Castana L, Francione S, Nobili L, Lo Russo G

To retrospectively evaluate seizure outcome in a case-series of patients with nodular heterotopy (NH)-related epilepsy treated by stereo-EEG (SEEG)-guided radio-frequency thermocoagulation (RF-THC) of the NH.Five patients (three male, age 5-33 years) with drug-resistant focal epilepsy presented a single NH at brain MRI. Following video-EEG monitoring, patients underwent SEEG recording to better identify the epileptogenic zone. All patients received RF-THC of the NH, using contiguous contacts of the electrodes employed for recording. The contacts for RF-THC lesions were chosen according to anatomical (intranodular position) and electrical (intranodular ictal low-voltage fast activity) criteria.At SEEG recordings, ictal discharge originated from the NH alone in three cases and from the NH and ipsilateral hippocampus in one case. In the remaining case, different sites of ictal onset, including the NH, were identified within the left frontal lobe. No adverse effects related to the RF-THC procedures were observed, apart from a habitual seizure that occurred during coagulation in one patient. Postprocedural sustained seizure freedom was detected in four cases (mean follow-up 33.5 months). In the case with left frontal multifocal ictal activity, RF-THC of the NH provided no benefit on seizures, and the patient is seizure-free after left frontal lobe resection.SEEG-guided RF-THC proved to be a safe and effective option in our small case-series of NH-related focal epilepsy. The indications to this treatment were strictly dependent on findings of intracerebral recording by SEEG, which can define the role of the NH in the generation of the ictal discharge. HubMed – drug