Ultrastructural Characteristics of Rat Hepatic Oval Cells and Their Intercellular Contacts in the Model of Biliary Fibrosis: New Insights into Experimental Liver Fibrogenesis.

PURPOSE: Recently, it has been emphasized that hepatic progenitor/oval cells (HPCs) are significantly involved in liver fibrogenesis. We evaluated the multipotential population of HPCs by transmission electron microscope (TEM), including relations with adherent hepatic nonparenchymal cells (NPCs) in rats with biliary fibrosis induced by bile duct ligation (BDL). METHODS: The study used 6-week-old Wistar Crl: WI(Han) rats after BDL for 1, 6, and 8 weeks. RESULTS: Current ultrastructural analysis showed considerable proliferation of HPCs in experimental intensive biliary fibrosis. HPCs formed proliferating bile ductules and were scattered in periportal connective tissue. We distinguished 4 main types of HPCs: 0, I, II (bile duct-like cells; most common), and III (hepatocyte-like cells). We observed, very seldom presented in literature, cellular interactions between HPCs and adjacent NPCs, especially commonly found transitional hepatic stellate cells (T-HSCs) and Kupffer cells/macrophages. We showed the phenomenon of penetration of the basement membrane of proliferating bile ductules by cytoplasmic processes sent by T-HSCs and the formation of direct cell-cell contact with ductular epithelial cells related to HPCs. CONCLUSIONS: HPC proliferation induced by BDL evidently promotes portal fibrogenesis. Better understanding of the complex cellular interactions between HPCs and adjacent NPCs, especially T-HSCs, may help develop antifibrotic therapies in the future.

Unfavorable effect of levetiracetam on cultured hippocampal neurons after hyperthermic injury.

BACKGROUND: The aim of this study was to examine the viability of neurons and the putative neuroprotective effects of second-generation antiepileptic drug, levetiracetam (LEV), on cultured hippocampal neurons injured by hyperthermia. METHODS: Primary cultures of rat's hippocampal neurons at 7day in vitro (DIV) were incubated in the presence or absence of LEV in varied concentrations under hyperthermic conditions. Cultures were heated in a temperature of 40°C for 24h or in a temperature of 41°C for 6h. Flow cytometry with Annexin V/PI staining as well as fluorescent microscopy assay were used for counting and establishing neurons as viable, necrotic or apoptotic. Additionally, the release of lactate dehydrogenase (LDH) to the culture medium, as a marker of cell death, was evaluated. Assessment was performed after 9DIV and 10 DIV. RESULTS: Incubation of hippocampal cultures in hyperthermic conditions resulted in statistically significant increase in the number of injured neurons when compared with non-heated control cultures. Intensity of neuronal destruction was dependent on temperature-value. When incubation temperature 40°C was used, over 80% of the population of neurons remained viable after 10 DIV. Under higher temperature 41°C, only less than 60% of neurons were viable after 10 DIV. Both apoptotic and necrotic pathways of neuronal death induced by hyperthermia were confirmed by Annexin V/PI staining. CONCLUSIONS: LEV showed no neuroprotective effects in the current model of hyperthermia in vitro. Moreover, drug, especially when used in higher concentrations, exerted unfavorable intensification of aponecrosis of cultured hippocampal neurons.

Study of the protective effects of nootropic agents against neuronal damage induced by amyloid-beta (fragment 25-35) in cultured hippocampal neurons.

BACKGROUND: Alzheimer's disease (AD) is a common neurodegenerative disorder, in which progressive neuron loss, mainly in the hippocampus, is observed. The critical events in the pathogenesis of AD are associated with accumulation of ß-amyloid (Aß) peptides in the brain. Deposits of Aß initiate a neurotoxic "cascade" leading to apoptotic death of neurons. Aim of this study was to assess a putative neuroprotective effects of two nootropic drugs: piracetam (PIR) and levetiracetam (LEV) on Aß-injured hippocampal neurons in culture. METHODS: Primary cultures of rat's hippocampal neurons at 7 day in vitro were exposed to Aß(25-35) in the presence or absence of nootropics in varied concentrations. Flow cytometry with Annexin V/PI staining was used for counting and establishing neurons as viable, necrotic or apoptotic. Additionally, release of lactate dehydrogenase (LDH) to the culture medium, as a marker of cell death, was evaluated. RESULTS: Aß(25-35) caused concentration-dependent death of about one third number of hippocampal neurons, mainly through an apoptotic pathway. In drugs-containing cultures, number of neurons injured with 20 µM Aß(25-35) was about one-third lesser for PIR and almost two-fold lesser for LEV. When 40 µM Aß(25-35) was used, only LEV exerted beneficial neuroprotective action, while PIR was ineffective. CONCLUSIONS: Our results suggest the protective potential of both studied nootropics against Aß-induced death of cultured hippocampal neurons with more powerful neuroprotective effects of LEV.

Study of the protective effect of calcium channel blockers against neuronal damage induced by glutamate in cultured hippocampal neurons.

BACKGROUND: The aim of this study was to examine the putative protective effect of calcium channel blockers on hippocampal neurons in the experimental model of excitotoxic damage. METHODS: Seven-day old primary dissociated cultures of rat hippocampal neural cells containing one of the following calcium channel blockers: cinnarizine, flunarizine or nimodipine were exposed to glutamate-induced injury. Quantitative assessments of neuronal injury were accomplished by measuring lactate dehydrogenase (LDH) activity in the media 24 h after exposure to glutamate and by counting and establishing the apoptotic and necrotic cells in flow cytometry with Annexin V-FITC/PI staining. RESULTS: In our experiment, glutamate induced a 339% elevation of apoptotic cells and a 289% increase of necrotic cells in hippocampal neurons as compared to control cultures without drugs. In cultures containing flunarizine, glutamate-induced cell apoptosis was suppressed by 62% while necrosis showed no significant alternation. Cinnarizine exerted no anti-apoptotic effects on glutamate-injured cultured hippocampal neurons, while nimodipine intensified the apoptotic pathway of cell death and promoted an increase in the number of apoptotic neurons by 26%. When cinnarizine or nimodipine were used, the percentage of necrotic cells was significantly lower when compared with glutamate-injured cultures and it amounted to 44% and 24% for cinnarizine and nimodipine, respectively. CONCLUSIONS: The obtained results suggest the beneficial anti-apoptotic potential of flunarizine and the anti-necrotic potential of cinnarizine against glutamate-induced death of cultured hippocampal neurons. Nimodipine can protect neurons against necrosis, but has an intensified adverse pro-apoptotic effect on cultured neurons in the experimental model of excitotoxic injury.

Hippocampus, hippocampal sclerosis and epilepsy.

Hippocampal sclerosis (HS) is considered one of the major pathogenic factors of drug-resistant temporal lobe epilepsy. HS is characterized by selective loss of pyramidal neurons - especially of sectors CA1 and CA3 of the hippocampus - pathological proliferation of interneuron networks, and severe glia reaction. These changes occur in the course of long-term and complex epileptogenesis. The authors, on the basis of a review of the literature and own experience, present the pathomechanisms leading to hippocampal sclerosis and epileptogenesis, including various morphological and functional elements of this structure of the brain and pharmacological possibilities of preventing these processes.

Ultrastructural study of hippocampal cortex neurons in an experimental model of valproate encephalopathy.

Valproate (VPA) is a widely used antiepileptic drug. A serious neurological-outcome defined as valproate encephalopathy (VE) may rarely occur during VPA therapy. Structural abnormalities within neurons are postulated as one of the reasons for VE. The aim of this study was to assess the ultrastructure of neurons in the hippocampal cortex during the course of chronic application of VPA to rats. VPA was chronically administered to rats, intragastrically, once daily at a dose of 200 mg/kg b.w. for 1, 3, 6, 9 and 12 months. The samples of hippocampal cortex, after routine laboratory preparation, were examined by electron microscopy. The drug induced pronounced ultrastructural changes in the population of pyramidal neurons within the hippocampal cortex after 9 and 12 months of VPA administration. The most expressed abnormalities were observed within the mitochondria and manifested by fragmentation of crests and almost complete disappearance of intramitochondrial granules. Mitochondria of numerous neurons resembled large vacuolar structures. Widening, shortening and irregular distribution of rough endoplasmic reticulum was also found. A characteristic feature of damaged neurocytes in the last two phases of the experiment was the disintegration of nuclear chromatin and the presence of numerous lipofuscin deposits within hyaloplasm. These cells assumed the look of "dark neurons" and presented the ultrastructural features of apoptosis and necrosis. Our results indicate that long-term VPA administration to rats leads to aponecrosis of hippocampal neurons.

A volumetric magnetic resonance imaging study of brain structures in children with Down syndrome.

BACKGROUND AND PURPOSE: Down syndrome (DS) is the most common genetic cause of mental retardation with deficits in language and memory. Mental retardation of varying degrees is the most consistent feature of DS. The objective of this study was to use high-resolution magnetic resonance imaging (MRI) techniques to investigate the volumes of the hippocampus, amygdala, and temporal and frontal lobes in children with DS compared with healthy children. MATERIAL AND METHODS: MRI of 49 patients was reviewed prospectively. The study included 23 children with DS (9 girls and 14 boys, mean age 6.7 ± 3.7 years) and 26 healthy children (11 girls and 15 boys, mean age 8.3 ± 2.4 years). Volumes of the right and left hippocampus, the right and left amygdala, temporal and frontal lobes and the total brain volume were measured by a radiologist who was unaware of the diagnosis. RESULTS: Total brain volume in children with DS was significantly lower compared with controls. It was associated with significantly lower volume of the frontal and temporal lobes. Children with DS had a significantly smaller right and left hippocampus volume and a significantly smaller right and left amygdala volume than did the control group. We also found a negative correlation between mental retardation and volume of the right hippocampus. CONCLUSIONS: The presence of these abnormalities from an early age contributes to the specific cognitive and developmental deficits seen in children with DS.

Levetiracetam protects hippocampal neurons in culture against hypoxia-induced injury.

Many experimental studies indicate that some antiepileptic drugs possess neuroprotective properties in varied models of neuronal injury. Levetiracetam is a second-generation antiepileptic drug with a novel mechanism of action. In the present study, we evaluated the putative neuroprotective effect of levetiracetam on primary hippocampal cultures at seven day in vitro. Cell death was induced by incubation of neural cultures in hypoxic conditions over 24 hours. Neuronal injury was assessed by morphometric investigation of death/total ratio of neurons in light microscopy using Trypan blue staining and by evaluation of lactate dehydrogenase (LDH) release in the culture medium. Our results indicate that pre-conditioning of hippocampal cultures with high concentrations of levetiracetam (100 µM and 300 µM) protects neurons against hypoxia-induced death. Two-fold higher number of neurons remained viable as compared to control cultures without drug. Lack of neuroprotective action of the drug on hippocampal neural cultures was observed, when a low concentration (10 µM) of levetiracetam was used.

Anti-inflammatory plasma cytokines in children and adolescents with migraine headaches.

Studies have shown fluctuations of cytokine levels in patients with migraine headaches; however, further studies are needed to verify these results. Our previous studies suggest increased levels of pro-inflammatory cytokines, such as IL-1alpha, sTNF-RI and TNF-alpha, in children with migraine headaches. In this study, we analyzed anti-inflammatory cytokines interleukin-4 (IL-4), interleukin-10 (IL-10) and interleukin-13 (IL-13) in plasma from children and adolescents with migraine and tension-type headaches during the interictal period. The study group consisted of 35 children and adolescents between 8-18 years old, suffering from migraine headaches with or without aura. The control group consisted of 33 patients suffering from episodic tension-type headaches. IL-4 was detected in 17.1% of patients with migraine headaches and in 28.6% of patients with tension-type headaches. IL-13 was detected in 17.1% of patients with migraine headaches and in 15.2% of patients with tension-type headaches. IL-10 was only detected in 3 of 68 (4.4%) patients. Any significant correlations between measurable cytokine levels and age, gender, aura, duration of disease, frequency and severity of headaches were determined. Any significant fluctuations of selected anti-inflammatory cytokines during the headache-free period in children with migraine and tension-type headaches have been found, immune dysfunction in migraineurs could not be excluded.

Amino acid metabolic processes in the temporal lobes assessed by proton magnetic resonance spectroscopy (1H MRS) in children with Down syndrome.

Down syndrome (DS), or trisomy 21, is one of the most common autosomal mutations. The overexpression of the ß-amyloid precursor protein gene, located on chromosome 21, causes an increased production of the specific amyloid. The current study is a continuation of our earlier investigations relating to the profile of metabolic changes in the frontal lobes of DS patients as assessed by proton magnetic resonance spectroscopy ((1)H MRS). The aims of the study were the morphological assessment of the brain using magnetic resonance imaging (MRI) and the evaluation of metabolic disorders of the temporal lobes using (1)H MRS in DS children. The study group included 20 children with DS aged 3-15 years and treated in the Department of Pediatric Neurology and Rehabilitation, Medical University of Bialystok. The control group included healthy children (n = 20). MRI scans of the heads of DS children were performed using a 1.5 T MR scanner under standard conditions. (1)H MRS investigations were also carried out to assess metabolic changes in the temporal lobes. Metabolites, such as N-acetylaspartate (NAA), glutamate-glutamine complex (Glx), choline (Cho), myoinositol (mI) and γ-aminobutyric acid (GABA), were determined in both temporal lobes with reference to the internal marker creatine (Cr). Results were compared with the control group.We found a statistically significant decrease in NAA/Cr, Cho/Cr, mI/Cr and GABA/Cr ratios. The Glx/Cr ratio in both temporal lobes of DS patients did not differ from the control group. Our results indicate metabolic neurotransmitter disorders in the central nervous system in children with DS.

Somatosensory evoked potentials in children with migraine with aura and without aura.

BACKGROUND: The Interictal abnormalities of cerebral information processing in migraine were found by studying different modality-specific evoked and event related potentials, mostly visual and auditory. In this study we focused on short-latency somatosensory evoked potentials (SEP) in children and adolescents suffering from migraine with and without aura. MATERIAL AND METHODS: The study group consisted 111 of children and adolescents at the age of 7-18 years: 27 of them suffered from migraine with aura, 36 of them suffered from migraine without aura, 48 subjects have episodic tension-type headache. SEPs was performed interictally at least two days after the last headache attack. RESULTS: There were no significant differences in the latency averages of SEP components between all migraneurs and tension-type headache subjects. However, N9 and N13 latency averages were significantly shorter in migraine without aura group compared with migraine with aura and tensiom type headaches. We did not find any significant correlations for either headache type between evoked potentials parametrs and illness duration, unilateral localisation of pain, migraine in family and aura. CONCLUSIONS: In concert with similar studies in adult migraineurs, our findings showed no disturbances of somatosensory information processing in children with migraine with aura and without aura. The diagnosis of migraine in children actually remains predominantly based on medical history. However, electrophysiological techniques allow the study of some of the structures in vivo and enlarge our knowledge on controversial aspects of migraine pathophysiology.

Anti-inflammatory plasma cytokines in children and adolescents with Down syndrome.

Cytokines participate in many physiological processes including the regulation of immune and inflammatory responses. Production of some important cytokines in children with Down syndrome (DS) is depressed or increased. In this study we analysed the selected anti- inflammatory cytokines: interleukin-4 (IL-4), interleukin-10 (IL-10), interleukin-13 (IL-13) in plasma of children and adolescents with DS. The study group consisted of 20 patients with Down syndrome and 33 healthy subjects at the age of 5-17 years. Levels of: IL-4, IL-10 and IL-13 in plasma samples were determined by specific enzyme- linked immunosorbent assay (ELISA) techniques according to manufacturer's instructions. IL-4 was detectable in 25% subjects with Down syndrome and in 28.6% healthy subjects. IL-13 was detectable in 15% patients with Down syndrome and in 15.2% healthy subjects, respectively. IL-10 was detectable in 1 of 20 patients with Down syndrome and in 2 of 33 healthy subjects only. No significant correlations between measurable cytokine levels and age and gender were found. No significant increased concentration of selected anti- inflammatory cytokines were detected.

Ultrastructure of the blood-brain barrier of the gyrus hippocampal cortex in an experimental model of febrile seizures and with the use of a new generation antiepileptic drug--topiramate.

The ultrastructure of the blood-brain barrier (BBB) of the gyrus hippocampal cortex in an experimental model of febrile seizures in rats and the effect of a new generation antiepileptic drug, topiramate, on the morphological status of this barrier were investigated. Advanced changes indicating a substantial increase in BBB permeability were observed in the animals with induced febrile seizures (FS), with approximately 2/3 of capillaries and perivascular astroglial processes being affected. Almost total occlusion of the capillary lumen was frequently seen, caused by damaged endothelial lining and by external pressure from markedly swollen perivascular astrocytic processes. Mitochondrial changes predominated among the abnormalities found in endoplasmic organelles of endothelial cells. Lesions in the BBB coexisted with damage to pyramidal neurons, mainly with features of aponecrosis ("dark neurons"). The study on topiramate seems to demonstrate its protective action on the BBB components of the ammonal cortex in the group receiving the drug as prevention, i.e. against febrile seizures. It was found to prevent marked BBB damage in over half of the capillaries. However, the application of topiramate directly after FS induction had no distinct beneficial effect on the structural BBB components.

Spastic cerebral palsy: clinical magnetic resonance imaging correlation of 129 children.

A prospective study was undertaken of 129 children with spastic cerebral palsy to clarify the relationship between magnetic resonance imaging (MRI) findings and clinical features of cerebral palsy. Low birth weight, asphyxia, prematurity, seizures, mental development, Gross Motor Function Classification System, and MRI findings were analyzed. Significant abnormalities relevant to the cerebral palsy were evident on imaging in 123 (95.3%). A similar percentage of MRI abnormalities were detected in the groups, 45 (100%) in patients with tetraplegic cerebral palsy, 37 (92.5%) in children with diplegic cerebral palsy, and 42 (95.4%) with hemiplegic cerebral palsy. Periventricular leukomalacia was detected more frequently in the children with spastic diplegia than in the patients with tetraplegia or hemiplegia. Cerebral atrophy was found more often in the tetraplegic group compared to the diplegic patients. Porencephalic cysts were detected more frequently in children with spastic hemiplegia. Congenital brain anomalies were found in a higher proportion in tetraplegic children. Significant correlations between the MRI findings and Gross Motor Function Classification System in the diplegic and tetraplegic patients were found. No correlations between the MRI results and risk factors for cerebral palsy in the tetraplegic patients were noted. Early detection of brain abnormalities in children with cerebral palsy may help in the prognosis and in the initiation of appropriate therapy