Differential impact of a ghrelin receptor antagonist or inverse agonist in the electrical kindling model of epilepsy

Ghrelin is a peptide, which has been shown to affect seizures. However, there is not a consensus about its real impact on the control of seizure severity. We assessed the influence of intra-amygdala injections of a ghrelin receptor (GHSR) antagonist, as well as a GHSR inverse agonist on the electrical kindling-induced seizures. Two unipolar electrodes and a tripolar electrode twisted with a guide cannula were implanted in the skull surface or the basolateral amygdala of adult male rats, respectively. A rapid electrical kindling protocol was applied for kindling epileptogenesis. The stimulations were applied until rats showed three consecutive stage five seizures. Each rat was considered as its control. D-Lys-3-GHRP-6 (1, 12.5, and 25 μg/rat) or [D-Arg, D-phe, D-Trp, heu] substance P (D-SP) (50, 500 and 5000 ng/rat) as the GHSR antagonist or inverse agonist were injected into the basolateral amygdala. Seizure parameters including after-discharge duration (ADD), stage five duration (S5D), and seizure stage (SS) were documented thirty minutes following administration of the drugs or saline. Antagonism of the GHSR in the amygdala, significantly increased seizure induction in the kindled rats, in a dose-dependent manner, and induced spontaneous seizures leading to status epilepticus. Conversely, D-SP had a dose-dependent anticonvulsant activity, indicated by decreased ADD and S5D. The results show that GHSR inverse agonism suppressed seizure severity in the rat amygdala kindling model, whereas GHSR antagonism made seizures more severe. Therefore, when considering the ghrelin system to modulate seizures, it is crucial to note the differential impact of various GHSR ligands.

Neuroprotective and anti-neuroinflammatory activity of frankincense in bile duct ligaion-induced hepatic encephalopathy

Objectives

Hepatic encephalopathy induces cognitive disturbances. Patients show neuroinflammation due to accumulation of toxic substances. Frankincense has neuroprotective and anti-inflammatory properties. Accordingly, we intended to evaluate the impact of frankincense on memory performance, inflammation, and the amount of hippocampal neurons in bile duct-ligated rats.

Materials and Methods

The bile duct was ligated in three groups of adult male Wistar rats (BDL groups). In two of these groups, frankincense was administered (100 or 200 mg/kg; by gavage) starting from one week before surgery to 28 days after surgery. The third BDL group received saline. In the sham group, the bile duct was not ligated and the animals received saline. Twenty-eight days after surgery, spatial memory was evaluated by the Morris water maze test. Five rats from each group were sacrificed to measure the expression of the hippocampal tumor necrosis factor-alpha (TNF-α). Three rats from each group were perfused to determine the amount of hippocampal neurons.

Results

Bile duct ligation impaired memory acquisition, while frankincense amended it. Bile duct ligation significantly increased the expression of TNF-α. Frankincense reduced TNF-α in BDL rats, significantly. The number of neurons in the hippocampal CA₁ and CA₃ areas was significantly lower in the BDL group and in the group that received frankincense (100 mg/kg) equated to the sham group. Frankincense (200 mg/kg) augmented the amount of neurons in the CA₁ area, slightly and in the CA₃ area, significantly.

Conclusion

The results indicate the anti-inflammatory and neuroprotective effects of frankincense in bile duct ligation-induced hepatic encephalopathy.

Down regulation of the hippocampal ghrelin receptor type-1a during electrical kindling-induced epileptogenesis

Numerous studies have shown that the ghrelin hormone is involved in epileptic conditions. However, the profile of ghrelin or its functional receptor mRNAs in seizure-susceptible brain areas was not assessed during epileptogenesis. Here, we measured the expression levels of the hippocampal ghrelin or its receptor mRNAs during electrical kindling-induced epileptogenesis. The study was conducted on twenty adult male Wistar rats. One tri-polar and two uni-polar electrodes were stereotaxically implanted in the baso-lateral amygdala or skull surface, respectively. Animals were divided into four groups, consisting of two sham groups (sham1 and sham2), and two other groups, which were partially or fully kindled. After the establishment of partial or full kindling, the hippocampi of the animals and that of the corresponding sham groups were removed. A quantitative real-time PCR technique was used to measure the expression levels of ghrelin or its functional receptor mRNAs. The results indicated that the expression levels of ghrelin did not alter in either of the partially or fully kindled rats compared to the corresponding sham groups. Ghrelin receptor (ghrelinR) down regulated, significantly in the fully-kindled rats, compared to sham2 group. Meanwhile, the mRNA expression levels of ghrelinR did not change in partially-kindled rats compared to sham1 group. The outcomes of the current study highlight the crucial, unknown impact of the hippocampal ghrelinR through the development of electrical kindling epileptogenesis, and points out the importance of ghrelinR as a goal to adjust epileptogenic progression.

Ameliorative effects of omega-lycotoxin-Gsp2671e purified from the spider venom of Lycosa praegrandis on memory deficits of glutamate-induced excitotoxicity rat model

Memory impairment is one of the main complications of Alzheimer's disease (AD). This condition can be induced by hyper-stimulation of N-Methyl-D-aspartate receptors (NMDARs) of glutamate in the hippocampus, which ends up to pyramidal neurons determination. The release of neurotransmitters relies on voltage-gated calcium channels (VGCCs) such as P/Q-types. Omega-lycotoxin-Gsp2671e (OLG1e) is a P/Q-type VGCC modulator with high affinity and selectivity. This bio-active small protein was purified and identified from the Lycosa praegrandis venom. The effect of this state-dependent low molecular weight P/Q-type calcium modulator on rats was investigated via glutamate-induced excitotoxicity by N-Methyl-D-aspartate. Also, Electrophysiological amplitude of field excitatory postsynaptic potentials (fEPSPs) in the input-output and Long-term potentiation (LTP) curves were recorded in mossy fiber and the amount of synaptophysin (SYN), synaptosomal-associated protein, 25 kDa (SNAP-25), and synaptotagmin 1(SYT1) genes expression were measured using Real-time PCR technique for synaptic quantification. The outcomes of the current study suggest that OLG1e as a P/Q-type VGCC modulator has an ameliorative effect on excitotoxicity-induced memory defects and prevents the impairment of pyramidal neurons in the rat hippocampus.

Antagonism of the ghrelin receptor type 1a in the rat brain induces status epilepticus in an electrical kindling model of epilepsy

Studies have shown the anti-seizure properties of the ghrelin hormone in different models of epilepsy. Nevertheless, the role of the endogenous ghrelin is unknown in the electrical kindling model of epilepsy. In this study, we evaluated the effect of the antagonism of the ghrelin receptors in the brain of fully kindled rats. Adult male Wistar rats weighing 300 g were used. Animals were stereotaxically implanted with two uni-polar electrodes in the skull surface and a tri-polar electrode in the basolateral amygdala, and a guide cannula in the left lateral ventricle. Animals underwent a rapid kindling protocol. After showing three consecutive stages of five seizures, the animals were considered fully kindled. D-Lys-3-GHRP-6 (1, 50, and 100 μg/rat) was injected intracerebroventricularly (i.c.v.) in the kindled animals. Each rat was considered as its control and received a single dose of D-Lys-3-GHRP-6. Seizure parameters including after discharge duration (ADD), seizure stage (SS), stage four latency (S4L), and stage five duration (S5D) were recorded. The paired t test indicated a significant increase in seizure induction. D-Lys-3-GHRP-6 (1 μg/rat; i.c.v.) prolonged ADD in the kindled rats, significantly. D-Lys-3-GHRP-6 (50 and 100 μg/rat; i.c.v.) induced spontaneous seizures, which led to status epilepticus in the kindled rats. The results indicate that the antagonism of the ghrelin functional receptors prolongs seizures and induces status epilepticus in the kindling model of epilepsy, and propose that the endogenous ghrelin signaling has crucial antiepileptic properties.

Differential expression levels of the hippocampal ghrelin and its receptor mRNA during memory consolidation

Ghrelin is a peptide, secreted mainly from the stomach. But, it is also produced in the brain. Studies have confirmed the positive impact of ghrelin on memory formation. However, the expression levels of ghrelin or its receptors were not measured in the brain during the process of memory formation. The probable alteration in the expression levels of ghrelin or its receptors in the brain during memory formation can be a reason for the contribution of its signaling in this process. We quantified the gene expression levels of ghrelin and its receptors in the hippocampus during fear and spatial memory consolidation. Thirty- nine adult male Wistar rats weighing 180-220 g were utilized. Memory consolidation was evaluated using the inhibitory avoidance task and Morris water maze. Rats were euthanized at different times (1, 3, and 24 h) post-training and their hippocampi were removed and freezed directly in liquid nitrogen. Quantitative real-time polymerize chain reaction (PCR) was used to quantify the messenger ribonucleic acid (mRNA) expression levels of the hippocampal ghrelin and its receptors. The mRNA levels of ghrelin exhibited a significant increase, 24 h post-training in the inhibitory avoidance task, while its receptor levels were down-regulated. Also, the mRNA expression levels of the hippocampal ghrelin were not changed significantly during memory consolidation in the Morris water maze, while its receptor showed a significant increase, 24 h post-training. The results show a differential profile of the expression levels of the hippocampal ghrelin or its receptor mRNA during fear or spatial memory consolidation. This proposes that a local increase in the hippocampal ghrelin or its receptor levels might be crucial for fear, and spatial memory consolidation. However, due to the small sample sizes, it is worth noting the preliminary nature of the conclusions in the present study.

Effects of quercetin-conjugated with superparamagnetic iron oxide nanoparticles on learning and memory improvement through targeting microRNAs/NF-κB pathway

Quercetin-conjugated superparamagnetic iron oxide nanoparticles (QCSPIONs) have an ameliorative effect on diabetes-induced memory impairment. The current study aimed to compare the effect of quercetin (QC) and QCSPIONs on inflammation-related microRNAs and NF-κB signaling pathways in the hippocampus of diabetic rats. The expression levels of miR-146a, miR-9, NF-κB, and NF-κB-related downstream genes, including TNF-α, BACE1, AβPP, Bax, and Bcl-2 were measured using quantitative real-time PCR. To determine the NF-κB activity, immunohistochemical expression of NF-κB/p65 phosphorylation was employed. Computer simulated docking analysis also performed to find the QC target proteins involved in the NF-κB pathway. Results indicate that diabetes significantly upregulated the expression levels of miR-146a, miR-9, TNF-α, NF-κB, and subsequently AβPP, BACE1, and Bax. Expression analysis shows that QCSPIONs are more effective than pure QC in reducing the expression of miR-9. Interestingly, QCSPIONs reduce the pathological activity of NF-κB and subsequently normalize BACE1, AβPP, and the ratio of Bax/Bcl-2 expression better than pure QC. Comparative docking analyses also show the stronger binding affinity of QC to IKK and BACE1 proteins compared to specific inhibitors of each protein. In conclusion, our study suggests the potent efficacy of QCSPIONs as a promising drug delivery system in memory improvement through targeting the NF-κB pathway.

Betahistine, prevents kindling, ameliorates the behavioral comorbidities and neurodegeneration induced by pentylenetetrazole

A seizure may occur because of the imbalance between glutamate and gamma-aminobutyric acid (GABA). Recurrent seizures induce some cognitive problems, such as, depression, learning and memory deficits, and neurodegeneration. Histamine is an appropriate therapeutic target for epilepsy via its effect on regulating neurotransmitter release. Also, evidence indicates the effect of histamine on neuroprotection and alleviating cognitive disorders. An ideal antiepileptic drug is a substance, which has both anticonvulsant effects and decreases the comorbidities that are induced by repeated seizures. Betahistine dihydrochloride (betahistine) is a structural analog of histamine. It acts as histamine H1 receptor agonist and H3 receptor antagonist, which enhances histaminergic neuronal activities. In the present study, we examined the effect of betahistine administration on seizure scores, memory deficits, depression, and neuronal loss induced by pentylenetetrazole (PTZ). Eight- to ten-week-old BALB/c male mice (20-25 g) received betahistine, 1, and 10 mg/kg daily from 7 days before the onset of PTZ-induced kindling until the end of the establishment of the kindling. We found that betahistine prevented generalized tonic-clonic seizures induction and diminished forelimb clonic seizures intensity. Also, it decreased cell death in the hippocampus and cortex, ameliorated the memory deficit and depression induced by PTZ in the kindled animals. Altogether, these results indicate that pretreatment and repetitive administration with betahistine exerts antiepileptogenic and anticonvulsant activity. These findings might be due to the neuroprotective impact of betahistine in the hippocampus and cortex.

Quercetin conjugated with superparamagnetic iron oxide nanoparticles improves learning and memory better than free quercetin via interacting with proteins involved in LTP

Biomedical application of quercetin (QT) as an effective flavonoid has limitations due to its low bioavailability. Superparamagnetic iron oxide nanoparticle (SPION) is a novel drug delivery system that enhances the bioavailability of quercetin. The effect of short time usage of quercetin on learning and memory function and its signaling pathways in the healthy rat is not well understood. The aim of this study was to investigate the effect of free quercetin and in conjugation with SPION on learning and memory in healthy rats and to find quercetin target proteins involved in learning and memory using Morris water maze (MWM) and computational methods respectively. Results of MWM show an improvement in learning and memory of rats treated with either quercetin or QT-SPION. Better learning and memory functions using QT-SPION reveal increased bioavailability of quercetin. Comparative molecular docking studies show the better binding affinity of quercetin to RSK2, MSK1, CytC, Cdc42, Apaf1, FADD, CRK proteins. Quercetin in comparison to specific inhibitors of each protein also demonstrates a better QT binding affinity. This suggests that quercetin binds to proteins leading to prevent neural cell apoptosis and improves learning and memory. Therefore, SPIONs could increase the bioavailability of quercetin and by this way improve learning and memory.

Effect of quercetin-conjugated superparamagnetic iron oxide nanoparticles on diabetes-induced learning and memory impairment in rats

Background

Diabetes mellitus plays a causative role in cognitive decline. Newly, neuroprotective effects of flavonoids have been widely investigated in neurodegenerative diseases. Quercetin (QC) is a phyto-derived bioactive flavone with numerous beneficial activities. However, its limited permeability to cross the blood–brain barrier, low oral bioavailability, poor aqueous solubility, and rapid gastrointestinal digestion lead to the administration of high dose of QC in clinical application.

Materials and methods

In order to overcome these limitations, we conjugated QC with superparamagnetic iron oxide nanoparticles (QCSPIONs) and supplemented streptozotocin-induced diabetic rats with it to improve diabetes-related memory impairment. In this regard, 40 rats were distributed into five groups with eight animals: control, diabetes, and diabetes treated with SPIONs, QC, and QCSPIONs. All treatments (at the dose of 25 mg/kg) were dissolved in deionized water and gavaged for 35 consecutive days.

Results

At the end of the study, QCSPIONs possessed significantly better efficacy than free QC on the improvement of memory performance. In the Morris water maze test, QCSPIONs compared to free QC reduced much better the escape latency over training trials (P<0.01) and increased the time spent in the target quadrant in probe trial (P<0.001). In the passive avoidance test, it increased step-through latency (P<0.05) and reduced the time spent in the dark compartment (P<0.01). In addition, both free QC and QCSPIONs were able to prevent the changes in body weight and decrease blood glucose levels in diabetic rats (P<0.05).

Conclusion

Overall, according to these results, we conclude that QC in the conjugated state with lower dose offers significantly higher potency in ameliorating diabetes-related memory impairment. Thus, this study offers an effective combined therapy for improving learning and memory.

Agmatine attenuates methamphetamine-induced passive avoidance learning and memory and CaMKII-α gene expression deteriorations in hippocampus of rat

Methamphetamine (METH) abuse is one the most worldwide problems with wide-ranging effects on the central nervous system (CNS). Chronic METH abuse can associate with cognitive abnormalities and neurodegenerative changes in the brain. Agmatine, a cationic polyamine, has been proposed as a neuromodulator that modulates many effects of abused drugs. The aim of this study was to determine if agmatine can decrease the impairment effect of METH on memory and hippocampal CaMKII-α gene expression, a gene that plays a major role in memory. Male wistar rats (200-220 g) were allocated into 7 groups, including 5 groups of saline, METH (1, 2 mg/kg), Agmatine (5, 10 mg/kg) and 2 groups of agmatine (5, 10 mg/kg) with higher doses of METH (2 mg/kg) for 5 consecutive days (n = 8 in each group). All injections were done intraperitoneally and agmatine was administrated 10 min before METH treatment. Furthermore, Passive avoidance learning (PAL) test was assessed on the 5th day. Retention test was done 24 h after training and the rats were sacrificed immediately. Hippocampi were removed and stored at -80 °C. Finally, hippocampal CaMKII-α gene expression was measured using Quantitative Real-time PCR. Our data showed that chronic METH dose-dependently impaired PAL retrieval, as it decreased step-through latency (STL) and increased time spent in the dark compartment (TDC). While Agmatine with a higher dose (10 mg/kg) significantly decreased impairment effect of METH (2 mg/kg) on PAL and memory. Also, molecular results revealed that METH (2 mg/kg) markedly decreased hippocampal CaMKII-α gene expression while agmatine (10 mg/kg) co-adminstration prevented it. Taken together, the results propose that agmatine may provide a potential therapy for learning and memory deficits induced by METH.

Using superparamagnetic iron oxide nanoparticles to enhance bioavailability of quercetin in the intact rat brain

Background

Quercetin (QT) as a bioactive flavonoid has a potential therapeutic activity for numerous neuronal injuries and neurodegenerative diseases. However, the low absorption rate of QT, especially through the blood-brain barrier, restricts its bioactivity in the body. The current research took the advantage of superparamagnetic iron oxide nanoparticles (SPIONs) to enhance the bioavailability of quercetin.

Methods

Quercetin conjugated with SPIONs was prepared by means of nanoprecipitation method and was characterized by X-ray diffractometer, scanning electron microscope, and Fourier transformed infrared spectrometer analyses. Wistar male rats were orally fed by gavage with QT and QT-SPION at 50 and 100 mg/kg daily doses for 7 days. Using high-performance liquid chromatography (HPLC) method, biodistribution of QT was evaluated in plasma and brain tissue.

Results

The outcomes of this research revealed a higher concentration in the plasma and brain of the rats fed with QT-SPION in comparison to free QT.

Conclusion

The results of this study confirm that SPION as a targeted drug delivery system enhances the bioavailability of quercetin in the brain about ten folds higher than free quercetin and could be used for the treatment of neurodegenerative disorders.

Quercetin Prevents Body Weight Loss Due to the Using of Superparamagnetic Iron Oxide Nanoparticles in Rat

Background:

Superparamagnetic iron oxide nanoparticles (SPION) have been largely considered for numerous applications in biomedicine such as magnetic resonance imaging, hyperthermia, cell tracking, anticancer treatment, and targeted delivery of drugs or genes. However, they may have side effects such body weight loss. Quercetin (QT), a strong antioxidant and free radical scavenger and a natural flavonoid, has a wide range of biological and therapeutic effects. In this study, the effect of QT on prevention of weight loss due to the using of SPION has been investigated.

Materials and Methods:

SPION and QT-SPION were administered orally at 50 and 100 mg/kg for 7 days. Then, the body weight was measured at the beginning and the end of the study.

Results:

Rats fed with 50 and 100 mg/kg SPION showed a significant weight loss, whereas those that fed with 50 mg/kg QT-SPION did not. A weight loss was observed in rats treated with 100 mg/kg of QT-SPION.

Conclusions:

The results of this study showed that quercetin could prevent weight loss due to the SPION.

Local injection of d-lys-3-GHRP-6 in the rat amygdala, dentate gyrus or ventral tegmental area impairs memory consolidation

It is well known that the hormone ghrelin affects learning and memory in different experimental models of learning. Though, the effect of antagonism of ghrelin receptor type 1a (GHS-R1a) in various regions of the brain and on different stages of learning has not been examined. In this study the effect of injection of a GHS-R1a selective antagonist (d-Lys-3-GHRP-6) into the basolateral amygdala, dentate gyrus or ventral tegmental area was examined on memory consolidation in the passive avoidance task. Adult male Wistar rats weighing 230-280g were used. Animals underwent stereotaxic surgery and cannulated in their amygdala, dentate gyrus or ventral tegmental area. One week after surgery, the rats received different doses of d-Lys-3-GHRP-6 (0.08, 0.8, and 8nM), immediately after training. The control groups received solvent of the drug. Twenty four hours later in the test day, memory retrieval was assessed. In all groups, post-training injection of d-Lys-3-GHRP-6 decreased step-through latency and increased entries into the dark compartment and time spent in the dark compartment, significantly and in a dose-dependent manner. The results indicate that antagonism of the GHS-R1a in the rat amygdala, dentate gyrus or ventral tegmental area impairs memory consolidation and show that the ghrelin signaling has a widespread influence on cognitive performance.

Rapid upregulation of the hippocampal connexins 36 and 45 mRNA levels during memory consolidation

Gap junction channels are implicated in learning and memory process. However, their role on each of the particular stages of memory formation has been studied less. In this study, the time profile of the expression levels of hippocampal connexins 36 and 45 (Cx36 and Cx45) mRNAs was measured during memory consolidation, in a passive avoidance paradigm. Totally 30 adult male rats were distributed into 5 groups of each 6. At different times profiles (30min, 3, 6 and 24h) following training, rats were decapitated and their hippocampi were immediately removed and frozen in liquid nitrogen. Total RNA was extracted and cDNA was synthesized, using oligo-dt primers. A quantitative real-time PCR was used to measure the levels of each of Cx36 and Cx45 mRNAs. Both connexins showed a rapid upregulation (30min) at the transcriptional level, which declined in later times and reached to the control level at 24h. The rapid up-regulation of Cx36 and Cx45 mRNAs might be accompanied with increasing intercellular coupling via gap junction channels and neuronal oscillatory activities required for memory consolidation. The results highlight the role of gap junctional coupling between hippocampal neurons during memory consolidation in the physiological conditions.

Therapeutic effect of frankincense in a rat model of Alzheimer's disease

OBJECTIVE

Frankincense improves memory in different models of learning. However, its influence on models of Alzheimer's disease (AD) has not been studied widely. In the present study, the therapeutic effect of frankincense was evaluated in a model of AD induced by i.c.v administration of streptozotocin.

MATERIALS AND METHODS

Under stereotaxic surgery, two guide cannulas were implanted in the lateral ventricles of adult male Wistar rats weighing 230-270 g. One group received streptozotocin (1.5 mg/kg/2μl/side) bilaterally on the first and third day of surgery. Another group received artificial cerebro-spinal fluid. Fourteen days after surgery, learning was evaluated using the passive avoidance paradigm. Four other groups of animals received frankincense (50 mg/kg) or its solvent after establishment of AD for 21 or 42 consecutive days, and then, memory retrieval was assessed.

RESULTS

Streptozotocin increased the number of stimulations required for induction of short-term memory and decreased step-through latency on the test day, significantly (p<0.05). Chronic injection of the aqueous extract of frankincense for 21 days did not affect learning parameters, but injection of it for 42 days, significantly increased step-through latency (p<0.05), decreased the number of step-through into the dark compartment (p<0.01) and decreased the time spent in the dark compartment (p<0.05).

CONCLUSION

The results indicate that chronic administration of frankincense has the potential to improve dementia type of AD induced by i.c.v injection of streptozotocin in a time-dependent manner.

Blocking the ghrelin receptor type 1a in the rat brain impairs memory encoding

Studies have shown that intracerebral administration of ghrelin hormone affects learning and memory in different experimental models of learning. However, the effect of antagonism of ghrelin receptor type 1a (GHS-R1a) on different stages of learning has not been investigated. In this study the effect of intracerebroventricular (i.c.v) injection of a GHS-R1a selective antagonist (d-Lys-3-GHRP-6) was examined on acquisition and consolidation of learning in the passive avoidance task. In total, 72 male Wistar rats weighing 230-280g were randomly distributed into 9 groups of 8 each. Animals underwent stereotaxic surgery and cannulated in their right ventricle. One week after surgery, the rats received different doses of d-Lys-3-GHRP-6 (0.2, 2, 20 and 80nM/5μl; i.c.v) 10min before, or (2, 20 and 80nM/5μl; i.c.v) immediately after training. The control groups received solvent of the drug. Twenty four hours later in the test day, memory retrieval was assessed. Pre-training injection of d-Lys-3-GHRP-6 decreased step-through latency (STL) and increased number of step-throughs into the dark compartment (NST) in a dose-dependent manner, but failed to be statistically significant. It also increased time spent in the dark compartment (TDC), significantly and in a dose-dependent manner. Post-training injection of d-Lys-3-GHRP-6 decreased step-through latency and increased time spent in the dark compartment and number of step-throughs into the dark compartment, significantly and in a dose-dependent manner. The results indicate that antagonism of the GHS-R1a in the rat brain impairs memory encoding on both acquisition and consolidation stages. Further studies are required to elucidate the main brain regions affected by the antagonist.

Blind source separation in characterizing ECG pre-shock waveforms during Ventricular Fibrillation

Ventricular Fibrillation (VF) is a cardiac arrhythmia for which the only available treatment option is defibrillation by electrical shock. Existing literature indicates that VF could be the manifestation of different sources controlling the heart with different degrees of organization. In this work we test the hypothesis that the pre-shock waveforms of successful and unsuccessful shock outcomes could be related to the number of independent sources present in these waveforms. The proposed method uses Blind Source Separation (BSS) to extract independent components in frequency direction from a pig database consisting of 20 pre-shock waveforms. The slope of the energy capture curve was used as an indicator to demonstrate the number of independent sources required to model the pre-shock waveforms. The results were also quantified by performing a linear discriminant analysis based classification achieving an overall classification accuracy of 75%. The results indicate that successful cases can be modeled with less number of independent sources compared to unsuccessful cases.

Expression of connexin 30 and connexin 32 in hippocampus of rat during epileptogenesis in a kindling model of epilepsy

OBJECTIVE

Understanding the molecular and cellular mechanisms underlying epileptogenesis yields new insights into potential therapies that may ultimately prevent epilepsy. Gap junctions (GJs) create direct intercellular conduits between adjacent cells and are formed by hexameric protein subunits called connexins (Cxs). Changes in the expression of Cxs affect GJ communication and thereby could modulate the dissemination of electrical discharges. The hippocampus is one of the main regions involved in epileptogenesis and has a wide network of GJs between different cell types where Cx30 is expressed in astrocytes and Cx32 exists in neurons and oligodendrocytes. In the present study, we evaluated the changes of Cx30 and Cx32 expression in rat hippocampus during kindling epileptogenesis.

METHODS

Rats were stereotaxically implanted with stimulating and recording electrodes in the basolateral amygdala, which was electrically stimulated once daily at afterdischarge threshold. Expression of Cx30 and Cx32, at both the mRNA and protein levels, was measured in the hippocampus at the beginning, in the middle (after acquisition of focal seizures), and at the end (after establishment of generalized seizures) of the kindling process, by real-time PCR and Western blot.

RESULTS

Cx30 mRNA expression was upregulated at the beginning of kindling and after acquisition of focal seizures. Then it was downregulated when the animals acquired generalized seizures. Overexpression of Cx30 mRNA at the start of kindling was consistent with the respective initial protein increase. Thereafter, no change was found in protein abundance during kindling. Regarding Cx32, mRNA expression decreased after acquisition of generalized seizures and no other significant change was detected in mRNA and protein abundance during kindling.

CONCLUSION

We speculate that Cx32 GJ communication in the hippocampus does not contribute to kindling epileptogenesis. The Cx30 astrocytic network localized to perivascular regions in the hippocampus is, however, overexpressed at the initiation of kindling to clear excitotoxic molecules from the milieu.

Changes in hippocampal connexin 36 mRNA and protein levels during epileptogenesis in the kindling model of epilepsy

OBJECTIVE

Identification of key molecular changes occurring during epileptogenesis provides better understanding of epilepsy and helps to develop strategies to modify those changes and thus, block the epileptogenic process. Gap junctional communication is thought to be involved in epileptogenesis. This communication can be affected by changes in expression of gap junctional protein subunits called connexins (Cxs). One of the main brain regions involved in epileptogenesis is the hippocampus in which there is a network of gap junctional communication between different cell types.

METHOD

Cx36 and Cx43 expressions at both mRNA and protein level were measured in rat hippocampus during epileptogenesis in the kindling model of epilepsy.

RESULTS

Cx36 expression at both mRNA and protein level was upregulated during acquisition of focal seizures but returned to basal level after acquisition of secondarily-generalized seizures. No change in Cx43 gene and protein expression was found during kindling epileptogenesis.

CONCLUSION

These results further point out the significance of Cx36 as a target to modify epileptogenic process and to develop antiepileptogenic treatments.

Seroprevalence of brucellosis and risk factors related to high risk occupational groups in Kazeroon, South of Iran

BACKGROUND

Brucellosis is a major zoonosis worldwide. Many people for their professions are at higher risk of contracting the disease.

OBJECTIVE

To determine the seroprevalence of brucellosis and its risk factors in a group of high risk professions.

METHODS

In a cross-sectional study, all personnel or students of veterinary schools, slaughters and butchers working in the city were invited to participate (n = 141). A comparison group (n = 44) randomly selected from patients who were selected at random from people attended our healthcare center for reasons other than the infectious diseases.

RESULTS

4 veterinarians, 15 veterinary assistants, 42 veterinarian students, 52 butchers, 17 slaughters, 8 slaughterhouse workers and 3 chefs made the first group and 14 storekeepers, 5 students of engineering, 11 clerks, 13 freelance workers, and 1 high school student made the comparison group. While the rate of consumption of most of the studied dairy products was almost similar in both groups, comparison group patients consumed more often milk (p<0.001) and cream (p<0.001) than the high risk group. 11 (7.8%; 95% CI: 3.4%-12.2%) cases from high risk group and none of the comparison group were found seropositive for Brucella.

CONCLUSION

Profession is the main factor in seropositivity. Consumption of dairy products and raw milk is not associated with a higher risk of seropositivity.

Should we screen for hypertension in general dental practice?

Hypertension is reported by the World Health Organisation as one of the most important causes of premature morbidity and mortality, although it is often asymptomatic. Approximately 40% of the UK population are thought to be affected, however, only one third of these are currently detected. Dental practice offers an ideal opportunity to screen for hypertension, due to the large cohort of the general population who regularly attend. A pilot study was carried out to screen for hypertension and associated risk factors in 114 consecutive patients who attended a city general dental practice. Results revealed that 39% (44) of the population screened had a high blood pressure reading but only 18% (8) of these were previously diagnosed as hypertensive, and 16% (7) had systolic readings greater than 160 mmHg. Of those currently receiving treatment for hypertension, the blood pressure was still elevated in 63% (5). This suggests that screening for hypertension in general dental practice may be of benefit to the population at large.

Antiepileptogenic and anticonvulsant activity of interleukin-1β in amygdala-kindled rats

Ischaemic, excitotoxic and traumatic brain injuries have been associated with the occurrence of epileptic seizures. Microglia, the principal immune cells in the brain, produce a variety of proinflammatory and cytotoxic factors especially interleukin-1 (IL-1) early after an acute insult. We studied the effect of intracerebroventricularly administered IL-1beta on seizure acquisition and on fully kindled seizures in amygdala kindling model of epilepsy. IL-1beta (0.01 ng/rat) retarded acquisition of kindled behavioral seizures and growth of afterdischarges (AD). IL-1beta (0.01-10 ng/rat) also exhibited significant anticonvulsant effect on established kindled seizures and AD duration. This effect began 0.5 h after administration and was continued up to 72 h. Pretreatment of the kindled animals with nitric oxide synthase inhibitor, N(G)-nitro-L-arginine methyl ester, or cyclooxygenase inhibitor, piroxicam, reversed the anticonvulsant effect of IL-1beta at early time points. Although most of the previous studies indicate a proconvulsant or convulsant property of IL-1, our results support a protective and antiepileptogenic role of IL-1beta.

Lipopolysaccharide retards development of amygdala kindling but does not affect fully-kindled seizures in rats

Seizures are common sequel to brain insults in cases such as stroke, trauma and infection where there is a certain neuroinflammation. Intracerebroventricular (i.c.v.) administration of lipopolysaccharide (LPS) induces an inflammatory state in brain that is used as a model of neuroinflammation. We studied the effect of LPS (0.25 and 2.5 microg/rat, i.c.v.) on development of electrical kindling of the amygdala and on fully-kindled seizures. LPS, at the doses used, had no effect on fully-kindled seizures and afterdischarge (AD) duration at 0.5, 2 or 4h after administration. However, daily injection of LPS (2.5 microg/rat) retarded acquisition of kindled behavioral seizures. This antiepileptogenic effect could be due to the release of inflammatory mediators from microglia and the related morphological and functional changes in synaptic neurotransmission.

Cutaneous leishmaniasis: what about a new, inexpensive, effective, topical herbal remedy?

Cutaneous leishmaniasis (CL) remains an important disease and public health problem in many parts around the world especially in the Middle East. In the absence of adequate treatment, the lesion could become chronic and disfiguring. We report on three cases with chronic CL lesions that were successfully treated with topical application of a new herbal mixture named "Z-HE". It is clearly demonstrated that this inexpensive, simple, effective and non toxic topical drug has a promising curative role in the treatment of CL.

Transient renal glucosuria in patients with tetanus

BACKGROUND/AIMS

During our early years of experience with patients suffering from tetanus, some of them were found to have unexplained renal glucosuria.

METHODS

Thus, all the normoglycemic patients with tetanus who were consecutively encountered over the subsequent 8 years were studied for the presence of renal glucosuria.

RESULTS

From 92 cases of tetanus admitted to the intensive-care unit, 63 patients had normal blood sugar in the course of their illness. The quantitative measurement of 24-hour urine confirmed the presence of significant renal glucosuria in 52% (n = 33) of these cases. The renal glucosuria was of transient nature and decreased to normal levels in the recovery stage (4 weeks after discharge from the hospital). There was no significant difference in age, sex, severity of disease and site of entry between the two groups of the patients with and without renal glucosuria.

CONCLUSION

Significant but transient glucosuria of renal origin possibly induced by tetanospasmin is common in patients with tetanus.