Involvement of dopamine D2-like receptors in the antiepileptogenic effects of deep brain stimulation during kindling in rats

Aims

Deep brain electrical stimulation (DBS), as a potential therapy for drug resistive epileptic patients, has inhibitory action on epileptogenesis. In the present investigation, the role of dopamine D₂-like receptors in the antiepileptogenic action of DBS was studied.

Methods

Seizures were induced in adult rats by stimulating the perforant path in a semi-rapid kindling method. Five minutes after the last kindling stimulation, daily DBS was applied to the perforant path at the pattern of low frequency stimulation (LFS; 1 Hz; pulse duration: 0.1 ms; intensity: 50–150 μA; 4 trains of 200 pulses at 5 min intervals). Sulpiride (10 μg/1 μl, i.c.v.), a selective dopamine D₂-like receptor antagonist, was administered prior to the daily LFS application.

Results

Kindling stimulations increased cumulative daily behavioral seizure stages, daily afterdischarge duration (dADD), and population spike amplitude (PS) in dentate gyrus following perforant path stimulation, while applying LFS decreased the kindled seizures' parameters. In addition, kindling potentiated the early (at 10–50 ms inter-pulse interval) and late (at 150–1000 ms inter-pulse interval) paired-pulse inhibition and decreased the paired-pulse facilitation (at 70–100 ms inter-pulse interval). These effects were also inhibited by applying LFS. All inhibitory effects of LFS on kindling procedure were prevented by sulpiride administration.

Conclusion

These data may suggest that LFS exerts its preventive effect on kindling development, at least partly, through the receptors on which sulpiride acts which are mainly dopamine D₂-like (including D₂, D₃, and D₄) receptors.     

Three-dimensional digital assessment of typodont activations

Objectives

Wax typodonts are widely used as pre-clinical teaching tools to test and research the complex force systems created by archwire activations, however, a limitation is the inability to quantify the resultant statically indeterminate tooth movements. The aim of this study was to develop an analogue-to-digital typodont system to quantify the effects of archwire activations on individual typodont teeth in three dimensions.

Methods

The typodont system was developed using CAD/CAM technology. Posterior expansion, squared, tapered, asymmetrical arch forms and reversed curve of Spee activations were tested with three repeats. The resulting three-dimensional movements of individual typodont teeth were assessed with six degrees of freedom (df). Cartesian coordinate systems were set for each tooth. Mesio-distal, bucco-lingual and intrusive–extrusive movements were assessed as changes in the location of the geometrically estimated centre of resistance in the x, y and z axes, respectively. Torque, tip and rotation movements were assessed as the rotations around the mesio-distal, bucco-lingual and intrusive–extrusive axes, respectively.

Results

Individual typodont tooth displacements from each activation could reliably be described with six df. The transversal-to-sagittal movement ratio ranged from 2:1 to 7:1, depending on the activation. Asymmetrical arch form activations caused a midline shift and affected the lateral overjet. Reversing the curve of Spee led to intrusion of incisors and second molars, extrusion of premolars and first molars and pronounced first and third order effects.

Conclusion

The digital typodont system is a promising teaching tool. The tested activations have implications in three dimensions, which should be considered when planning tooth movements.     

Multipara with utero-vesical fistula following repeat cesarean section: a rare iatrogenic complication

Utero-Vesical fistulas are the rarest of all urogenital fistulas, with most cases occurring after cesarean section. Its prevalence is increasing worldwide because of the increasing indications of cesarean section. Patient usually presents with urine leak, amenorrhea and cyclic hematuria. Herein, we present a case of patient presenting with complain of severe urinary tract infection following cesarean section. Review and update of recent literature regarding the diagnostic imaging of this entity are described.