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.

Therapists' perspectives on a new portable hand telerehabilitation platform for home-based personalized treatment of stroke patients

OBJECTIVE

Patients who have sustained a stroke suffer from residual motor impairments. Stroke can limit their ability to employ their impaired upper limb properly. Hand function is particularly one of the most frequently persisting consequences of stroke. This paper introduces a new portable hand telerehabilitation platform (PHTP) for home-based personalized treatment of stroke patients. The aims of this study are (1) to document the iterative design and development process of the PHTP, and (2) to explore the therapists' perspectives on implementing home-based treatment of stroke patients.

MATERIALS AND METHODS

Local therapists were involved early in designing and developing the PHTP. We collected views of 84 therapists practicing in North America via an online survey.

RESULTS

Therapists' perspectives on the introduced prototype support the use of the PHTP to provide home-based telerehabilitation for stroke patients. The System Usability Scale score was 70 for the PHTP, indicating that the platform is usable. The rest of the qualitative results obtained from custom questionnaires showed consistency in the platform design, high perceived usability and good acceptability among the therapists' community.

CONCLUSIONS

In sum, the results encourage and support fine-tuning of the PHTP, commercializing it, and conducting prospective clinical studies.

Determinants of Prognosis in Triple-Negative Breast Cancer: Report from a Large Breast Cancer Registry

BACKGROUND

The outcome of patients with triple-negative breast cancer (TNBC) is highly dependent on demographic factors and ethnicity. We aimed to evaluate the clinicopathological determinants of prognosis among women with TNBC using data from one of the largest breast cancer (BC) registries.

METHODS

A total of 6145 patients with BC from our referral center were evaluated from 1995 to 2018, among whom 523 had TNBC. The baseline, menstrual and reproductive, treatment and pathology related characteristics were evaluated.

RESULTS

Among TNBC patients, the rate of stage 3 and 4 BC (29.9% vs. 14.4% and 7.8% vs. 0% for stage 3 and 4, respectively; P<0.001), invasive ductal carcinoma (90.7% vs. 75.6%; P=0.004), nodal involvement (46.7% vs. 33.4%; P=0.026), mastectomy (57.3% vs. 37.8%; P=0.001) and axillary node dissection (76.7% vs. 59.8%; P=0.019) was significantly higher in the group that developed recurrence. Disease-free-survival was 80.6% (157.76 ± 9.48 months) and overall-survival was 90.1% (182.73 ± 3.28 months). For death, stage 3 BC (compared to stages 0 and 1 as base) showed a higher risk of earlier death (adjusted HR: 4.191, 95% CI=1.392-12.621; P=0.011). For recurrence, stage 3 BC (adjusted HR: 1.044, 95% CI=1.209-6.673; P=0.017) (compared to stages 0 and 1 as base) showed significantly higher risk for developing earlier recurrence. Moreover, those who had invasive ductal carcinoma (compared to other types of BCs) had a higher risk for developing earlier recurrence (adjusted HR: 3.307, 95% CI=1.191-0.724; P=0.012).

CONCLUSION

BC stage plays a significant role in both earlier recurrence and earlier mortality among patients with TNBC.

Investigating the effective annual dose of radiation angiography department of Afshar Hospital in Yazd and providing radiation protection strategies to better manage the dose received by staff

Introduction: Due to the increasing use of angiography procedures and the higher risk of deterministic and stochastic effects for radiation workers of these sections than other radiological procedures, radiation safety is very important among angiography staff. Therefore, this study aimed to obtain the effective dose of angiography staff, compare them with the standard dose limit, and finally outline the strategies for occupational dose reduction in angiography. Methods: In this study, the report of film dosimetry of angiography staff was studied and the effective periodic and annual doses of 34 radiographs were reported from the year 2015 to 2018. The relationship between effective dose and body mass index, work experience, gender and age of staff was also evaluated. Results: The results showed that the average effective dose of the physicians, nurses and radiographers in 2 months period were 0.2 mSv and their average annual effective dose were 1.6, 1.2 and 1.2, respectively. In addition, there were no significant relationship between effective dose and work experience, age, sex and BMI of the radiation workers. Conclusion: The effective dose of radiation in this study is less than the annual dose.. Low effective doses do not make their radiation protection less important because this reduction can be due to radiation protection by personnel in this ward. Therefore, as far as possible, radiation protection measures should be taken to reduce the radiation exposure of catheterization lab staff. In these radiologists thyroid protection, eyes, gonads, and the organs that are usually outside the lead apron is of great importance.

Occupational eye dose to medical staff in various interventional cardiologic procedures: is the need for lead goggles the same in all groups of radiation workers?

Considering the increased use of interventional cardiologic procedures and concern about irradiation to the eyes, it is necessary to measure eye dose in radiation workers. The assessment of eye dose using collar dose is a routine but inaccurate method. Therefore this study was designed to measure eye dose in the radiation workers of various interventional cardiologic procedures. In this study eye dose was measured for left and right eyes in three groups of radiation workers in angiography ward of Afshar hospital in various procedures using TLD. Measurements were done separately for cardiologists, nurses and radio-technologists in 100 procedures. The nurses functioned as surgical assistants and were usually close to the table. The correlation of staff dose to exposure parameters was also investigated. Eye dose in physicians were higher than other staff in all procedures. Also the left eye dose was considerably higher than right one, especially for physicians. The median equivalent dose per procedure of left eye for physicians, nurses and radio-technologists were 7.4, 3.6, 1.4 µSv (PCI) and 3.2, 3.1, 1.3 µSv (Adhoc) and 3.2, 1.7, 1.1 µSv (CA), respectively. The annual left eye equivalent dose with (without) using lead goggles were 2.4 (15.3), 1.4 (2.2), 1.0 (1.1) mSv for physicians, nurses and radio-technologists, respectively. There were also a positive correlation between eye dose and KAP for procedures without lead goggles. The lead goggles showed lower protection effects for radio-technologists than other staff. Only 30% of physicians received a dose higher than 1/3 of the ICRP annual dose limit, therefor only physician eye dose should be monitored in catheterization labs.

Deep brain stimulation restores the glutamatergic and GABAergic synaptic transmission and plasticity to normal levels in kindled rats

Background

The precise effect of low frequency stimulation (LFS) as a newly postulated, anticonvulsant therapeutic approach on seizure-induced changes in synaptic transmission has not been completely determined.

Hypothesis

In this study, the LFS effect on impaired, synaptic plasticity in kindled rats was investigated.

Methods

Hippocampal kindled rats received LFS (4 trials consisting of one train of 200 monophasic square waves, 0.1 ms pulse duration, 1 Hz) on four occasions. LTP induction was evaluated using whole-cell recordings of evoked excitatory and inhibitory post-synaptic potentials (EPSPs and IPSPs respectively) in CA1 neurons in hippocampal slices. In addition, the hippocampal excitatory and inhibitory post-synaptic currents (EPSCs and IPSCs), and the gene expression of NR₂A, GluR₂ and γ₂ were evaluated.

Results

LTP induction was attenuated in excitatory and inhibitory synapses in hippocampal slices of kindled rats. When LFS was applied in kindled animals, LTP was induced in EPSPs and IPSPs. Moreover, LFS increased and decreased the threshold intensities of EPSCs and IPSCs respectively. In kindled animals, NR₂A gene expression increased, while γ₂ gene expression decreased. GluR2 gene expression did not significantly change. Applying LFS in kindled animals mitigated these changes: No significant differences were observed in NR₂A, γ₂ and GluR₂ gene expression in the kindled+LFS and control groups.

Conclusion

The application of LFS in kindled animals restored LTP induction in both EPSPs and IPSPs, and returned the threshold intensity for induction of EPSCs, IPSCs and gene expression to similar levels as controls.

Modeling of carrier dynamics in InGaAs/GaAs self-assembled quantum dot lasers

In this study, a theoretical model is used to simulate the lasing characteristics of InGaAs/GaAs self-assembled quantum dot lasers. The rate equation for InGaAs/GaAs is numerically solved using the fourth-order Runge-Kutta method. We consider the homogeneous and inhomogeneous broadening of the optical gain, both with and without considering the nonlinear gain. The results indicate that for a certain injected current, there is a specific homogeneous broadening (HB) with the best lasing performance when HB is near, comparable, or equal to inhomogeneous broadening for every laser-injected current. We show that if the linear optical gain is replaced by the total gain, the output power will reduce a little and the peaks will be more broadened and the maximum of the gain spectrum decreases. The time evolution of the photon number for different currents and different HBs is shown. The results indicate that by increasing the HB, the number of photons in the steady state and the delay in the starting oscillation will increase. In addition, we show that there is threshold coverage for quantum dots to begin lasing and an optimum quantum dot coverage in which the self-assembled quantum dot lasers operate with the lowest possible threshold current and maximum output power.

Investigation of subwavelength grating structure for enhanced surface plasmon resonance detection

A metallic subwavelength grating structure built on a thin gold film is studied for surface plasmon resonance (SPR) detection of refractive index variations of biological buffer solutions. By employing finite element analysis as a numerical method, characteristics of the angle interrogated SPR sensor were calculated and discussed in a broad operating wavelength varying from visible to near-infrared (NIR). The effects of grating structural parameters such as grating depth, grating period, and grating fill factor in different operating wavelengths have been evaluated on the sensor performance parameters of sensitivity, full width at half-minimum, minimum reflectance at resonance, and resonance angle. Numerical results indicate that adjusting grating geometrical parameters can enhance the performance parameters of the sensor especially in the NIR wavelengths. The enhanced sensor performance parameters for optimizing grating geometry have been explored in detail for visible and NIR wavelengths of 633 and 984 nm, respectively. These findings are important for developing localized surface plasmon sensors with enhanced performance.

Design study of nanograting-based surface plasmon resonance biosensor in the near-infrared wavelength

A key issue with surface plasmon resonance (SPR) biosensors, which are the focus of many researchers, is improving their sensitivity to detect lower amounts of analyte in a solution. Most SPR developments have focused on the grating-based sensitivity-enhancement approach. In addition to sensitivity, a substantial enhancement of other sensor characteristics such as resolution and signal-to-noise ratio (SNR) is desired for designing a practical sensor. So, in this paper, the characteristics of surface plasmon polaritons sustained by 1D subwavelength metallic gratings on a thin metal slab (under the Krestchmann configuration) have been investigated numerically for the analyte-ligand interactions detection. Effects of different structural parameters, such as grating period, grating depth, metal film thickness, and fill factor have been evaluated on the sensor sensitivity as well as resolution and SNR. Numerical results indicate that the sensor working in the near-infrared wavelength has a better performance than that in the visible one. The result of numerical investigation has been used to design an optimized sensor with the best figure of merit.

The effect of hydroalcoholic extract of Stachys lavandulifolia vahl on pregnant mice

OBJECTIVES

Stachys lavandulifolia is commonly used for many health problems including anxiety. A couple of reports indicate that this plant might have an abortifacient effect on pregnant women. Here we examined this effect on pregnant mice.

MATERIALS AND METHODS

Incremental doses of 0, 50, 100, 150 and 200 mg/kg of the extracts or normal saline (control group) were injected intraperitoneally to the pregnant mice between 7(th) to 12(th) days of pregnancy. On day 16, uterine tubes were resected and absorbed fetuses were counted.

RESULTS

Our study showed that the different average of absorbed fetuses between treated and control groups is significant (P < 0.05). S. lavandulifolia changes the activity level of hypothalamus-pituitary gland-gonad axis due to flavonoid compounds. Also, S. lavandulifolia decreases progesterone concentration resulting in a significant difference between treated and control groups (P < 0.05) and gives rise to failure in fetus survival and consequently, abortion. The length and weight of fetuses decreased in treated groups and there was a significant difference between treated and control groups (P < 0.05).

CONCLUSION

Owing to the possible abortive effect of Stachys lavandulifolia, it is highly recommended to use it cautiously during pregnancy.

High performances III-Nitride Quantum Dot infrared photodetector operating at room temperature

In this paper we present a novel long wave length infrared quantum dot photodetector. A cubic shaped 6nm GaN quantum dot (QD) within a large 18 nm Al(0.2)Ga(0.8)N QD (capping layer) embedded in Al(0.8)Ga(0.2)N has been considered as the unit cell of the active layer of the device. Single band effective mass approximation has been applied in order to calculate the QD electronic structure. The temperature dependent behavior of the responsivity and dark current were presented and discussed for different applied electric fields. The capping layer has been proposed to improve upon the dark current of the detector. The proposed device has demonstrated exceptionally low dark current, therefore low noise, and high detectivity. Excellent specific detectivity (D*) up to approximately 3 x 10(8)CmHz(1/ 2)/W is achieved at room temperature.

Type of cell death and the role of acetylcholinesterase activity in neurotoxicity induced by paraoxon in cultured rat hippocampal neurons

Organophosphate (Ops) neurotoxicity is attributed both to its well-known cholinergic and non-cholinergic effects. In the present study we compared enzymatic and morphologic changes in neurons exposed to paraoxon during one day and one week. The effect of exposure time is important in neurotoxicity of Ops. The longer the exposure time is the more damage is observed in neurons, although there are few investigations about the effect in the post-exposure period. Hippocampal cells were obtained from rat neonates and cultured in Neurobasal/B27. Paraoxon at 50 and 100 microM were added. Inverted microscope and electron microscope were used to study cell morphology and Neutral Red staining was used to measure viability. We also assayed caspase-3 and (acetylcholinesterase) AChE activity. Hoechst staining was utilized to determine the type of cell death. Culture medium was replaced after 24 h in one-day group, however, tests were all carried out at the end of the first week in both group. The results indicate that paraoxon reduced the viability in a dose-dependent manner. Our results do not confirm apoptosis in either group; it seems that the cell death in one-day exposure group was not AChE dependent. In conclusion, present data imply that the toxicity of paraoxon is both dose and duration dependent, which may even remain after the cessation of exposure.

Modeling and simulation of ammonia removal from purge gases of ammonia plants using a catalytic Pd-Ag membrane reactor

In this work, the removal of ammonia from synthesis purge gas of an ammonia plant has been investigated. Since the ammonia decomposition is thermodynamically limited, a membrane reactor is used for complete decomposition. A double pipe catalytic membrane reactor is used to remove ammonia from purge gas. The purge gas is flowing in the reaction side and is converted to hydrogen and nitrogen over nickel-alumina catalyst. The hydrogen is transferred through the Pd-Ag membrane of tube side to the shell side. A mathematical model including conservation of mass in the tube and shell side of reactor is proposed. The proposed model was solved numerically and the effects of different parameters on the rector performance were investigated. The effects of pressure, temperature, flow rate (sweep ratio), membrane thickness and reactor diameter have been investigated in the present study. Increasing ammonia conversion was observed by raising the temperature, sweep ratio and reducing membrane thickness. When the pressure increases, the decomposition is gone toward completion but, at low pressure the ammonia conversion in the outset of reactor is higher than other pressures, but complete destruction of the ammonia cannot be achieved. The proposed model can be used for design of an industrial catalytic membrane reactor for removal of ammonia from ammonia plant and reducing NO(x) emissions.

The correlation between Modified Ashworth Scale scores and the new index of alpha motoneurones excitability in post-stroke patients

The Modified Ashworth Scale (MAS) is currently a widely used clinical scale to evaluate muscle spasticity. However, it lacks reliability and the validity, of the MAS as a clinical measure of muscle spasticity has been challenged. The aim of the present study was to examine the validity of the MAS in patients with wrist flexor spasticity after stroke by using the Hslope/Mslope (Hslp/Mslp) ratio as the new index of alpha motoneuron excitability. Twenty-seven adult patients (14 women and 13 men) with first ever stroke resulting in hemiplegia with a mean (SD, range) age of 57.9 (11.6, 37-75) were included in the study. The main outcome measures were the MAS for the clinical assessment of spasticity, and the Hslp/Mslp for the neurophysiological evaluation. There was not a significant correlation between the MAS scores and Hslp/Mslp ratio (r = 0.38, p > 0.05). The mean of the Hslp/Mslp did not show a hierarchical increase with the MAS scores. The findings indicate that the MAS is not a valid and ordinal level measure of muscle spasticity.

Neurophysiological examination of the Modified Modified Ashworth Scale (MMAS) in patients with wrist flexor spasticity after stroke

The Modified Modified Ashworth Scale (MMAS) is a clinical test for the measurement of spasticity. The aim of the present study was to examine the validity of the MMAS in patients with wrist flexor spasticity after stroke. 27 adult patients (14 women and 13 men) with first ever stroke resulting in hemiplegia with a mean (SD, range) age of 57.9 (11.6, 37-75) were included in the study. The outcome measures were the MMAS for the clinical assessment of spasticity, the Hslope/Mslope (Hslp/Mslp), and the H(max)/M(max) ratio for the neurophysiological evaluation. The mean of the Hslp/Mslp and the H(max)/M(max) were higher in patients with worse MMAS grades but the differences were not statistically significant. There was a significant positive correlation between the MMAS scores and Hslp/Mslp ratio as the new index of alpha motoneurone excitability or traditional index of H(max)/M(max) ratio (r = 0.39, p = 0.04). It is concluded that the MMAS to be a valid measure of spasticity after stroke.

A preliminary study into the criterion validity of the Modified Modified Ashworth Scale using the new measure of the alpha motoneuron excitability in spastic hemiplegia

The Modified Ashworth Scale (MAS) is the most widely used clinical test for the measurement of muscle spasticity. This scale that suffers from limitations and lack of reliability and validity has recently been remodified. The aim of the present study is to investigate the criterion validity of the new Modified MAS(MMAS) in the upper limb in post-stroke hemiplegia, using the Hslope/Mslope (Hslp/Mslp) as a novel index of alpha motor neuron excitability. Prior to the validity study, the reliability of the MMAS was evaluated in 30 hemiplegic patients. The raters agreed on 23 patients (0. 76%). The MMAS had good inter-rater reliability (K= 0.63, SE = 0.11, p < 0.001) for the assessment of wrist flexors spasticity in hemiplegic patients. 12 adult patients (7 women and 5 men) with first ever stroke resulting in hemiplegia with a mean age of 58.9 +/- 11.9 years (range, 37-73) were included in the validity study. The outcome measures were the MMAS for the clinical assessment of spasticity, and the HslopelMslope and the Hmax/Mmax ratio for the electrophysiological evaluation. The results showed an increase in mean rank of Hslp / Mslp in patients with a score of 1, 2 or 3 on the MMAS. However, the difference among the groups was not significant (p > 0.05). There was also no relationship between the clinical scale of MMAS and either the traditional [Hmax / Mmax ratio (r = -0.06)] or the new index [Hslp / Mslp (r = 0.24)] of spinal excitability. This preliminary study recruited a small number of patients, and failed to confirm a linear correlation between these variables. A study with a large number of patients is suggested to clarify the outcome.

Paraoxon-induced ultrastructural growth changes of rat cultured hippocampal cells in neurobasal/B27

Organophosphates (OPs) neurotoxicity is attributed both to their well-known cholinergic and recently attended non-cholinergic effects. Since parathion has been observed to be responsible for more cases of poisoning than any other OP insecticides, it is vitally important to investigate other mechanisms, besides cholinesterase inhibition, which can potentially contribute to the neurotoxicity of parathion (or its metabolite, paraoxon). In present study, hippocampal cells obtained from Wistar rat neonates were cultured in neurobasal medium supplemented with B27 serum where different doses of paraoxon were also introduced. The neuronal growth in the control group and those exposed to paraoxon was compared. Phase contrast microscopy, cell staining (Neutral Red) and computer assessment morphometric study (Motic) were used to study cell morphology, viability and type of cell death. Statistical analysis was carried out using one-way ANOVA. There was no clear morphologic differences between neurons in the control group and those exposed to 10 microM paraoxon; however, deformity of the soma was clear in pellets containing higher concentration of paraoxon. Ultrastructure of cells was markedly altered at 50 microM dose of paraoxon as evidenced by gradual discontinuation of cytoplasm, appearing of numerous vacuoles and intracytoplasmic myelin figure. The processes (neurites) did not grow in media containing 100 microM paraoxon or more. Viability decreased with increasing paraoxon especially above 100 microM. In conclusion, the present data reveal that paraoxon, in 30 microM or higher concentrations, induces a decrease in cell growth, followed by cell swelling and neuronal death (possibly necrosis).

Involvement of nucleus accumbens in L-arginine-induced conditioned place preference in rats

In the present study, the effects of intraperitoneal, intra-accumbal and intra-ventral tegmental area administration of L-arginine and N(G)-nitro-L-arginine methyl-ester (L-NAME) on conditioned place preference behavior were studied. Intraperitoneal (i.p.; 0.5, 1 and 5 mg/kg) and intra-accumbal (intra-NAc; 0.3, 1 and 3 microg/rat), but not intra-ventral tegmental area (intra-VTA; 0.3, 1 and 3 microg/rat) administrations of L-arginine produced a significant place conditioning. Similar injections of L-NAME did not produce any response. However, intraperitoneal pretreatment of the animals with L-NAME (5, 10 and 20 mg/kg), 30 min before L-arginine administration, significantly abolished the acquisition of place conditioning induced by either intraperitoneal or intra-accumbal injection of L-arginine. Moreover, injection of L-NAME (5, 10 and 20 mg/kg) on the test day did not alter the L-arginine response. The results may indicate that L-arginine induces conditioned place preference via an increase in nitric oxide (NO) in the nucleus accumbens.

Determination of cyproterone acetate in plasma samples by high-performance liquid chromatography

A rapid and sensitive high-performance liquid chromatographic method for the determination of cyproterone acetate in human plasma has been developed. The chromatographic separation was performed on an analytical mbondapak C8 column (125 yen 4.6 mm, i.d) with an isocratic mobile phase consisting of methanol-water (62.38 v/v). Using ultra violet detection at 282 nm, the detection limit for cyproterone acetate in plasma was 10 ng/ml. The calibration curve was linear over the concentration range 50-160. 0 ng/ml. Cyproterone was isolated from plasma by liquid-liquid extraction and the recovery was about 90% for plasma. The inter-day and intra-day assay coefficients of variation were found to be less than 10%.