Proteasome inhibitors against amelanotic melanoma.

The incidence of malignant melanoma, the most aggressive skin cancer, is increasing constantly. Despite new targeted therapies, the prognosis for patients with metastatic disease remains poor. Thus, there is a need for new combinational treatments, and antineoplastic agents potentially valuable in this approach are inhibitors of the ubiquitin-proteasome system (UPS). In this work, we analyze the cytotoxicity mechanisms of proteasome inhibitors (MG-132, epoxomicin, and lactacystin) in a specific form of melanoma which does not synthesize melanin-the amelanotic melanoma (Ab cells). We found that the most cytotoxic of the compounds tested was epoxomicin. Caspase-9 activation as well as cytochrome C and AIF release from mitochondria indicated that exposure to epoxomicin induced the mitochondrial pathway of apoptosis. Epoxomicin treatment also resulted in accumulation of Bcl-2 family members-proapoptotic Noxa and antiapoptotic Mcl-1, which were postulated as the targets for bortezomib in melanoma. Inhibition of caspases by BAF revealed that cell death was partially caspase-independent. We observed no cell cycle arrest preceding the apoptosis of Ab cells, even though cdk inhibitors p21Cip1/Waf1 and p27Kip1 were up-regulated. The cell cycle was blocked only after inactivation of caspases by the pan-caspase inhibitor BAF. In summary, this is the first study exploring molecular mechanisms of cell death induced by epoxomicin in melanoma. We found that Ab cells died on the mitochondrial pathway of apoptosis and also partially by the caspase-independent way of death. Apoptosis induction was fast and efficient and was not preceded by cell cycle arrest.

Interleukin-1ß-immunoreactive neurons in the hippocampus and paraventricular nucleus of the hypothalamus after stress stimulation in aged versus adult rats.

It is believed that the impact of stress on interleukin-1ß (IL-1ß) depends on the ontogenetic age. This study examines the influence of acute or chronic exposure to forced-swim (FS) stress or high-light open-field (HL-OF) stimulation on the expression of IL-1ß. Double immunofluorescence staining was used to reveal the density of IL-1ß/NeuN (NeuN is a neuronal nuclear marker)-immunoreactive (-ir) cells in the hippocampal subfields CA1 and CA3, dentate gyrus (DG), and paraventricular nucleus (PVN) of the hypothalamus. Adult postnatal day 90 (P90) and aged (P720) rats were used in this experiment. The data showed a significant increase in the density of IL-1ß/NeuN-ir cells in the CA1, CA3, DG, and PVN in P720 nonstressed rats in relation to P90 control animals. Neither FS nor HL-OF acute stimulation caused alteration in the density of IL-1ß-ir neurons in any of the investigated structures in P90 and P720 rats in comparison with control groups. However, chronic FS caused a significant increase in CA3 and DG of P720 rats, and chronic HL-OF led to a significant increase in the density of IL-1ß-ir neurons in the PVN of P90 rats and in all hippocampal subfields of P720 animals. These results indicate that chronic HL-OF stimulation is a factor that induces changes in the number of IL-1ß-ir neurons in the PVN of adult rats, whereas both chronic FS and HL-OF are aggravating factors for the hippocampus of aged (P720) animals.

Variations in popliteal fossa venous anatomy: implications for diagnosis of deep-vein thrombosis.

BACKGROUND: To retrospectively review the bilateral venous system within the popliteal fossa to evaluate the types of variations and their frequency seen in venous anatomy. MATERIALS AND METHODS: During routine dissection of formalin-fixed cadavers, a retrospective review of 32 bilateral (64 limbs) lower limbs obtained from adult donors was performed. Deep veins present in the popliteal fossa were evaluated according to predetermined criteria for the presence of duplication of vessels and interindividual variations in venous anatomy. RESULTS: More than one deep venous vessel was seen in the popliteal fossa in 20 (31.3%) of 64 limbs. In 12 (18.7%) cases there was a high (just below the level of the adductor hiatus) origin of the popliteal vein: from 2 tributaries in 10 (15.6%) and 3 tributaries in 2 (3.1%). In 5 (7.8%) cases true duplicated popliteal veins were observed. There were also 3 (4.7%) cases, including one bilateral, of persistent sciatic vein. CONCLUSIONS: Variations in popliteal fossa venous anatomy are common and have important implications for the diagnosis of deep vein thrombosis.

A rare variations of the cephalic vein drainage: two cases report.

Throughout the years, anatomic studies have demonstrated numerous variations in the course of the cephalic vein (CV). There are, however, very rare cases of uncommon formation, course or termination of the vein to which our attention should be drawn. During a routine dissections conducted in the Department of Anatomy and Neurobiology, in two formalin-fixed cadavers, the very rare anatomical variants were found. In 80 year-old Caucasian female the right cephalic vein, after crossing the clavipectoral triangle, ascended anterior and superior to the clavicle and drained into the lateral branch of the right external jugular vein, which in turn opened to the right subclavian vein. In the second case, the dissection of 83 year-old Caucasian male cadaver revealed that after passing through the deltopectoral groove, the left cephalic vein run between clavicle and subclavius muscle to terminate in the left subclavian vein. Understanding of the topography, morphology and anatomical variations of the cephalic vein is important not only for the anatomists but for the clinicians and nurses as well. Such knowledge can prevent multiple complications during many invasive procedures including implantation of Cardiac Implantable Electronic Devices, central venous access, arteriovenous fistula creation or even iatrogenic injuries during clavicle or glenohumeral joint surgery.

Mesenchymal stem cells transfer mitochondria to allogeneic Tregs in an HLA-dependent manner improving their immunosuppressive activity.

Cell-based immunotherapies can provide safe and effective treatments for various disorders including autoimmunity, cancer, and excessive proinflammatory events in sepsis or viral infections. However, to achieve this goal there is a need for deeper understanding of mechanisms of the intercellular interactions. Regulatory T cells (Tregs) are a lymphocyte subset that maintain peripheral tolerance, whilst mesenchymal stem cells (MSCs) are multipotent nonhematopoietic progenitor cells. Despite coming from different origins, Tregs and MSCs share immunoregulatory properties that have been tested in clinical trials. Here we demonstrate how direct and indirect contact with allogenic MSCs improves Tregs' potential for accumulation of immunosuppressive adenosine and suppression of conventional T cell proliferation, making them more potent therapeutic tools. Our results also demonstrate that direct communication between Tregs and MSCs is based on transfer of active mitochondria and fragments of plasma membrane from MSCs to Tregs, an event that is HLA-dependent and associates with HLA-C and HLA-DRB1 eplet mismatch load between Treg and MSC donors.

JNK/p66Shc/ITCH Signaling Pathway Mediates Angiotensin II-induced Ferritin Degradation and Labile Iron Pool Increase.

Angiotensin II (Ang II) induces deleterious changes in cellular iron metabolism and increases the generation of reactive oxygen species. This leads to an impairment of neuronal and vascular function. However, the mechanism underpinning Ang II-induced changes in iron metabolism is not known. We hypothesized that Ang II-induced ferritin degradation and an increase in the labile iron pool are mediated by the c-Jun N-terminal kinase (JNK)/p66Shc/ITCH signaling pathway. We show that Ang II treatment induced ferritin degradation in an endothelial cell lines derived from the bovine stem pulmonary artery (CPAE), human umbilical vein endothelial cells (HUVEC), and HT22 neuronal cells. Ferritin degradation was accompanied by an increase in the labile iron pool, as determined by changes in calcein fluorescence. The JNK inhibitor SP600125 abolished Ang II-induced ferritin degradation. Furthermore, the effect of Ang II on ferritin levels was completely abolished in cells transfected with vectors encoding catalytically inactive variants of JNK1 or JNK2. CPAE cells expressing inactive ITCHor p66Shc (substrates of JNK kinases) were completely resistant to Ang II-induced ferritin degradation. These observations suggest that Ang II-induced ferritin degradation and, hence, elevation of the levels of highly reactive iron, are mediated by the JNK/p66Shc/ITCH signaling pathway.

Changes in NGF/c-Fos double staining in the structures of the limbic system in juvenile and aged rats exposed to forced swim test.

This study aimed to investigate the influence of acute (a single 15 min) and chronic (15 min daily for 21 days) exposure to forced swim (FS) test on nerve growth factor (NGF)/c-Fos cells in hypothalamic paraventricular (PV) and supraoptic (SO) nuclei, the central (CeA) and medial (MeA) amygdaloid nuclei and CA3-hippocampus in juvenile (P28) and aged (P360) rats. The double-immunofluorescence (-ir) method was used to detect NGF-ir and c-Fos-ir cells. The amount of NGF/c-Fosir cells in relation to all NGF-ir cells is shown as a percentage. In the acute FS test an increase in NGF/c-Fos-ir cells (P<.05) was observed in all studied structures of juvenile rats and in the PV and SO of the aged individuals. After chronic FS stress, the NGF/c-Fos-ir ratio remained unaltered (except in the SO) in P28, but it increased (P<.05) in all investigated regions in P360 compared with the controls. The findings may reflect the state of molecular plasticity within the limbic hypothalamicpituitary- adrenocortical (HPA) axis in both age groups, yet the phenomenon of habituation in NGF/c-Fos-ir after chronic FS exposure was observed only in juvenile animals.

Nicotine-induced CREB and DeltaFosB activity is modified by caffeine in the brain reward system of the rat.

Coffee and nicotine consumption are frequently combined, indicating possible intensifying effect of caffeine on smoking behavior, although neurobiological background of this phenomenon remains unknown. We aimed at determining the effect of caffeine and nicotine, applied separately or simultaneously, on activation of six structures of the brain reward system: nucleus accumbens (NAc), ventral tegmental area (VTA), amygdala (Amg), hippocampus (Hip), medial prefrontal cortex (mPfr) and dorsal striatum (CdP) in the adult male Wistar rats. Activation of two transcription factors, the phosphorylated form of cyclic AMP-response element binding protein (pCREB) and DeltaFosB (ΔFosB) was assessed by immunohistochemistry after multiple-dose five-days psychostimulants administration followed by 20min and 24h survival, respectively. Nicotine evoked the highest increase of pCREB-immunoreactivity (-ir) in NAc, while caffeine exerted the weakest effect in mPfr and CdP. Nicotine/caffeine co-administration resulted in decrease of pCREB-ir in NAc and increase in Amg, compared with the effect of each psychostimulant used separately. Nicotine was the strongest psychostimulant activating ΔFosB-ir in Amg, whereas caffeine - in Hip. Nicotine/caffeine-exerted effect upon ΔFosB-ir in Amg was weaker, whereas in mPfr stronger, than nicotine-evoked effect in these structures. In summary, pCREB and ΔFosB activation is dependent on the type of stimulus, brain structure and functional context. Activation of both transcription factors is responsible for caffeine's modifying effect upon nicotine-related behaviors and must be taken into account while quitting cigarette smoking.

Distribution of the parvalbumin, calbindin-D28K and calretinin immunoreactivity in globus pallidus of the Brazilian short-tailed opossum (Monodelphis domestica).

This study describes the topography, borders and divisions of the globus pallidus in the Brazilian short-tailed opossum (Monodelphis domestica) and distribution of the three calcium binding proteins, parvalbumin (PV), calbindin D-28k (CB) and calretinin (CR) in that nucleus. The globus pallidus of the opossum consists of medial and lateral parts that are visible with Nissl or Timm's staining and also in PV and CR immunostained sections. Neurons of the globus pallidus expressing these proteins were classified into three types on the basis of size and shape of their soma and dendritic tree. Type 1 neurons had medium-sized fusiform soma with dendrites sprouting from the opposite poles. Neurons of the type 2 had medium-to-large, multipolar soma with scarce, thin dendrites. Cell bodies of type 3 neurons were small and either ovoid or round. Immunostaining showed that the most numerous were neurons expressing PV that belonged to all three types. Density of the PV-immunopositive fibers and puncta correlated with the density of the PV-labeled neurons. Labeling for CB resulted mainly in the light staining of neuropil in both parts of the nucleus, while the CB-expressing cells (mainly of the type 2) were scarce and placed only along the border of the globus pallidus and putamen. Staining for calretinin resulted in labeling almost exclusively the immunoreactive puncta and fibers that were distributed with medium-to-high density throughout the nucleus. Close to the border of globus pallidus with the putamen these fibers (probably dendrites) were long, thin and varicous, while more medially bundles of thick, short and smooth fibers predominated. Single CR-ir neurons (all of the type 3) were scattered through the globus pallidus. Colocalization of two calcium binding proteins in one neuron was. never observed. The CB-ir puncta (probably terminals of axons projecting to the nucleus) frequently formed basket-like structures around the PV-ir neurons. Therefore, the globus pallidus in the opossum, much as that in the rat, consists of a heterogeneous population of neurons, probably playing diversified functions.

The dentin sialoprotein (DSP) expression in rat tooth germs following fluoride treatment: an immunohistochemical study.

UNLABELLED: Fluoride is known to alter expression of dentin matrix proteins and affect their posttranslational modifications. OBJECTIVE: The objective of our study was to examine dentin sialoprotein (DSP) expression in the early and late bell stages of development of the first molar tooth germs in rats treated with fluoride. DESIGN AND METHODS: Pregnant dumps were divided into three groups. They were fed a standard diet and from the fifth day of pregnancy, each group received either tap water (with trace amounts of fluoride), tap water with a low concentration of fluoride, or tap water with a high concentration of fluoride. Changes in DSP expression and distribution were visualized by immunohistochemistry. RESULTS: Immunoreactivity for DSP was detected in the cervical regions of the early bell stage in tooth germs of the 1-day-old animals. The earliest reaction was visible in the control group and the group supplemented with the low fluoride concentration (F(L)) but not in the group supplemented with the high fluoride concentration (F(H)). In early bell stages across all experimental groups, the immunoreactivity to DSP was observed in the cusp tip regions and was localized to preameloblasts, young and mature odontoblasts, dental pulp cells, predentin, and dentin. Generally, more intense positive staining for DSP was detected in animals supplemented with the high fluoride concentration. In the late bell stage found in the 4-day-old control group and the group supplemented with the low fluoride concentration, immunoreactivity for DSP was less intense compared with younger animals. However, immunoreactivity was greater in the group treated with the high dose of fluoride. In this group, the positive immunostaining for DSP, especially in young ameloblasts, was prolonged and relatively strong. CONCLUSIONS: Fluoride supplementation causes changes in the developmental pattern of DSP expression and its distribution in rat tooth germs.

The anatomical relationships between the serotonergic afferents and the neurons containing calcium-binding proteins in the rat claustrum.

Claustrum is a telencephalic structure integrating information of various modalities. Proper functioning of this structure depends on the presence of a network of intrinsic connections. This includes GABA-ergic neuronal populations that also contain calcium-binding proteins (CaBPs). The goal of this study was to analyze qualitative and quantitative the 5-HT-containing fibers in the rat claustrum and to assess the relationships between these fibers and the populations of claustral neurons expressing CaBPs. We used the methods of immunocytochemistry and morphometry. The serotonergic fibers in the claustrum are heterogeneous, both with respect to their morphology and spatial distribution. Thin varicose fibers are more numerous and are homogeneously distributed within the claustrum. Remaining fibers were thicker and possessed larger varicosities. They were present mainly in the ventral part of the claustrum. Although the serotonergic fibers are found in the vicinity of claustral cells containing CaBPs, direct contacts between these fibers and cells are rare. Other mechanisms, including volume transmission, may possibly mediate serotonergic influences.

Morphological Changes within the Rat Lateral Ventricle after the Administration of Proteasome Inhibitors.

The broad variety of substances that inhibit the action of the ubiquitin-proteasome system (UPS)-known as proteasome inhibitors-have been used extensively in previous studies, and they are currently frequently proposed as a novel form of cancer treatment and as a protective factor in intracerebral hemorrhage treatment. The experimental data on the safest route of proteasome inhibitor administration, their associated side effects, and the possible ways of minimizing these effects have recently become a very important topic. The aim of our present study was to determine the effects of administering of MG-132, lactacystin and epoxomicin, compounds belonging to three different classes of proteasome inhibitors, on the ependymal walls of the lateral ventricle. Observations were made 2 and 8 weeks after the intraventricular administration of the studied substances dissolved in dimethyl sulfoxide (DMSO) into the lateral ventricle of adult Wistar rats. Qualitative and quantitative analysis of brain sections stained with histochemical and inmmunofluorescence techniques showed that the administration of proteasome inhibitors caused a partial occlusion of the injected ventricle in all of the studied animals. The occlusion was due to ependymal cells damage and subsequent ependymal discontinuity, which caused direct contact between the striatum and the lateral nuclei of the septum, mononuclear cell infiltration and the formation of a glial scar between these structures (with the activation of astroglia, microglia and oligodendroglia). Morphologically, the ubiquitin-positive aggregates corresponded to aggresomes, indicating impaired activity of the UPS and the accumulation and aggregation of ubiquitinated proteins that coincided with the occurrence of glial scars. The most significant changes were observed in the wall covering the striatum in animals that were administered epoxomicin, and milder changes were observed in animals administered lactacystin and MG-132. Interestingly, DMSO administration also caused damage to some of the ependymal cells, but the aggresome-like structures were not formed. Our results indicate that all of the studied classes of proteasome inhibitors are detrimental to ependymal cells to some extent, and may cause severe changes in the ventricular system. The safety implications of their usage in therapeutic strategies to attenuate intracerebral hemorrhagic injury and in brain cancer treatment will require further studies.

The influence of mild stressors on neurons containing interleukin-1ß in the central (CeA) and medial (MeA) amygdala in the ageing process of rats.

Proinflammatory cytokine - interleukin 1ß (IL-1ß) plays an important role in stress reactions in the structures of limbic system. The impact of stress on IL-1ß may depend on the ontogenetic age. The study examined the influence of acute and chronic exposure to forced swim (FS) or high-light open-field (HL-OF) stressors on neurons containing IL-1ß. Double immunofluorescence staining was used to reveal the density of IL-1ß/NeuN (NeuN - a neuronal nuclear marker) - immunoreactive (ir) cells in the amygdaloid central (CeA) and medial (MeA) nuclei, which are closely involved in the regulation of emotional stressors and hypothalamic-pituitary-adrenal axis (HPA) activation. Adult (P90; P - postnatal day), middle-aged (P360), and aged (P720) male Wistar Han rats were used in these experiments. We observed an age-dependent increase in the basal density of IL-1ß/NeuN-ir cells in CeA and MeA in P90 vs. P360 and P360 vs. P720 rats. Neither acute nor chronic FS caused significant changes in the density of IL-1ß-ir neurons in any of the investigated nuclei in P90, P360, and P720 rats as compared with the non-stressed groups. However, chronic but not acute HL-OF caused a marked increase in the density of IL-1ß/NeuN-ir cells in the CeA and MeA of P360 rats and in MeA of the P720 animals. Moreover, chronic HL-OF led to an increase in the density of IL-1ß-ir neurons in relation to acute HL-OF in the CeA and MeA of both P360 and P720 rats. Our results may indicate the involvement of IL-1ß neurons in the development of ageing processes in CeA and MeA. Furthermore, our results point out that chronic HL-OF is an aggravating factor that induces an increase in the density of IL-1ß/NeuN-ir cells in the MeA and/or CeA of middle-aged and aged rats. The increase is possibly due to insufficient control of the HPA axis associated with involutional ageing processes and seems to be a common denominator of the ageing process and stress.

Mechanism of leflunomide-induced proliferation of mitochondria in mammalian cells.

Leflunomide (LFM) is an inhibitor of mitochondrial enzyme dihydroorotate dehydrogenase (DHODH) that catalyzes the conversion of dihydroorotate to orotate coupled with the generation of reactive oxygen species (ROS) from mitochondria. We demonstrate here that LFM causes an unrestrained proliferation of mitochondria both in human osteosarcoma cell line 143B cells and rat liver derived RL-34 cells. Increases in the total mass of mitochondria per cell in LFM-treated cells were evidenced by the application of Green FM or 10-n-nonyl acridine orange to flow cytometry, an enhanced replication of mtDNA and electron microscopy. Externally added uridine improved the disturbance in cell cycle progression in LFM-treated cells, but failed to suppress such unrestrained mitochondrial proliferation. On the contrary, lapacol and 5-fluoroorotate, inhibitors of DHODH besides LFM, suppressed the biogenesis of mitochondria during the cell cycle progression. LFM, but not lapacol or 5-fluoroorotate, caused increases of the intracellular level of acetylated alpha-tubulin. These data suggest that the inhibition of DHODH may not be at least primarily related to the LFM-induced abnormal proliferation of mitochondria, and support our recent published observation that changes in the physicochemical properties of microtubules may be in someway concerned with the biogenesis of mitochondria.

Dual effect of 2-methoxyestradiol on cell cycle events in human osteosarcoma 143B cells.

We have demonstrated for the first time that the steroid metabolite, 2-methoxyestradiol (2-ME) is a powerful growth inhibitor of human osteosarcoma 143 B cell line by pleiotropic mechanisms involving cell cycle arrest at two different points and apoptosis. The ability of 2-ME to inhibit cell cycle at the respective points has been found concentration dependent. 1 microM 2-ME inhibited cell cycle at G1 phase while 10 microM 2-ME caused G2/M cell cycle arrest. As a natural estrogen metabolite 2-ME is expected to perturb the stability of microtubules (MT) in vivo analogously to Taxol--the MT binding anticancer agent. Contrary to 2-ME, Taxol induced accumulation of osteosarcoma cells in G2/M phase of cell cycle only. The presented data strongly suggest two different mechanisms of cytotoxic action of 2-ME at the level of a single cell.

Distribution of immunoreactivity of calcium-binding proteins in the rabbit piriform cortex.

The piriform cortex has been extensively studied due to its possible role in epileptogenic activity. Neurones containing calcium-binding proteins (CaBPs), as a component of inhibitory circuitry, seem to be critically involved in this pathological process. The aim of the present study was to characterise the pattern of distribution of CaBPs-immunoreactivity in the piriform cortex of the adult rabbit. It comprises labelled cells, fibres (often with varicosities) and terminals. It varies among the layers. Moreover, the distribution of the parvalbumin- and calretinin-immunoreactive fibres and terminals allows even further subdivision of the layer I into two sublayers. Calretinin-ir neurones are located in subpial (Ia) layer, while parvalbumin - as well as calbindin-D28k-ir ones are mainly located in the second and third layer. Cajal-Retzius-like neurones containing calretinin, Chandelier cells containing parvalbumin and basket cells containing calbindin D28k and parvalbumin can be distinguished among labelled subpopulations of CaBPs neurones. In general, the pattern of PV- CR- and CB-immunoreactivity is similar to that previously characterised in other mammals, i.e., rats, guinea pigs, hedgehog, and tenrecs. The pattern is organised in topographic fashion confirming the complexity of regulatory circuits in the rabbit piriform cortex.

Developmental expression of SNAP-25 protein in the rat striatum and cerebral cortex.

The developmental changes of 25-kDa synaptosomal-associated protein (SNAP-25) expression in the rat striatum and cerebral cortex were examined using Western- blotting and densitometric scanning of immunoblots. Analysis of the striatum extracts from postnatal day 0 (P0) to postnatal day 120 (P120) demonstrated that SNAP-25 is poorly expressed until P14. From this point the expression level gradually increases to reach a maximum on P60 and then decreases. The pattern of SNAP-25 expression in the rat cerebral cortex is different. Two peaks are observed, the first on P10 and the second on P60, after which the expression level decreases. These results appear to confirm the role of SNAP-25 protein in axon outgrowth and synaptogenesis in the nervous system.

Developmental changes in nitric oxide synthase protein expression in the rat striatum and cerebral cortex.

We examined the expression of brain nitric oxide synthase (bNOS) in two developing rat brain structures, the striatum and the cerebral cortex. For this purpose, we quantified the relative protein concentration level using the Western blotting method and densitometric scanning. 32 Wistar rats, divided according to survival period (PO-P120-postnatal days) were used in this study. Our results demonstrate that bNOS expression rises in these structures during the first week of postnatal life, reaching a maximum in the striatum on the 10th day and in the cerebral cortex on the 7th day of postnatal life. After the period of increase the expression declines and after the 14th day a stabilisation of bone protein concentration is observed, both in the striatum and the cerebral cortex. These changes in bone protein expression might be related to the important role of nitric oxide in the developing rat brain, especially in synaptogenesis, apoptosis and neurotransmission.

The morphology of acinar cells during acute pancreatitis in rats induced by intraductal infusion of peracetate.

Many experimental models have been created to explain the pathophysiology of acute pancreatitis (AP). Investigations have been undertaken in this laboratory into the influence of strong oxidants introduced into the pancreas retrogradely through the bile-pancreatic duct. In these experiments a potentially toxic metabolite of ethanol-peracetic acid was used to induce AP. Wistar rats were treated with 1 mM and 40 mM peracetate and with a solvent as a control for 1 and 3 hours respectively. After a period of observation the samples of pancreata were examined in a light and electron microscope together with the content of sulphydryl groups as a marker of intracellular oxidative stress. The morphological examination showed profound changes in the histology of the pancreas and also in its subcellular structures, especially in groups 3 and 4 (with a higher concentration of peracetate). The changes included parenchymal haemorrhage and widespread acinar cell necrosis. The level of the sulphydryl groups decreased in the rats treated with peracetate. This suggests that the severity of the disease strongly depends on the intensity of the oxidative stress. The results confirmed the axial role of oxygen-derived free radicals in the pathogenesis of AP.

Postnatal development of the somatosensory thalamocortical projection in rat and rabbit--a combined retrograde transport and stereological comparative study.

A comparative quantitative study of the somatosensory thalamocortical connections in the rat and rabbit, labeled with the fluorescent retrograde tracer Fluoro-Gold (FG), was conducted by means of unbiased stereology. FG was injected into the primary somatosensory cortex of the rat and rabbit in different age groups from P0 to P180 (P-postnatal day). The numerical density of retrogradely labeled the ventroposterolateral (VPL) projection neurons was analyzed. A significant decrease in this parameter was observed during the first two weeks of postnatal life in both studied species. Changes of the neuropil volume and selective elimination of early cortical connections stemming from the VPL may possibly cause this process. A withdrawal of axon collaterals from the expanded cortical sites as well as apoptosis (existing both in the VPL and parietal cortex) contribute to a decrease in the numerical density. Our observations allow us to conclude that the thalamocortical somatosensory connections established before the birth undergo significant quantitative changes in both studied species during the first two weeks of postnatal life and this period seems to be crucial for maturation of the thalamocortical loop.