GSTO1 acts as a mediator in sodium fluoride-induced alterations of learning and memory related factors expressions in the hippocampus cell line.

The mechanism of GSTO1, as a high-risk factor for neurological damage, in sodium fluoride (NaF)-induced learning and memory impairment remained still unclear. Hence, in this study, we used the siRNA-GSTO1 HT22 model to explore the effect of NaF and siRNA-GSTO1 on the viability, and proliferation rate of HT22 cells, as well as the mRNA and protein expression levels of cyclic adenosine monophosphate (cAMP) response element binding protein (CREB), neural cell adhesion molecule (NCAM), stem cell factor (SCF) and brain-derived neurotrophic factor (BDNF). The results of MTT showed that 10-3, 10-4, and 10-5 moL/L sodium fluoride (NaF) exposure could significantly promote the proliferation of HT22 cells at 24 h, 36 h, and 48 h, respectively. In addition, our results showed that exposure to 10-3, 10-4, and 10-5 moL/l NaF increased GSTO1 mRNA and protein expression, but decreased CREB and BDNF expression levels in a dose and time-dependent manner. The mRNA and protein expressions of GSTO1, CREB and BDNF were significantly decreased in the siRNA-GSTO1 and NaF + siRNA-GSTO1 group (P < 0.05). We have shown that various NaF doses affected the learning and memory ability by down-regulation the expressions of CREB, BDNF, NCAM and SCF. In summary, we concluded that GSTO1 plays a mediator role in NaF-induced neurological damage.

El uso de placebo en ensayos clínicos de fase III en Brasil / The use of placebos in phase III clinical trials in Brazil

El Consejo Federal de Medicina de Brasil (CFM) -órgano normativo y fiscalizador del ejercicio ético de la medicina- prohibió, en 2008, la participación de médicos brasileños en investigaciones que utilizaran placebo para enfermedades con tratamiento eficaz y efectivo, en contraposición a la Declaración de Helsinki, que permite su uso en condiciones metodológicamente justificadas. Con el objetivo de verificar si la normativa ética del CFM modificó el uso de placebo en ensayos clínicos de fase III en Brasil, se analizaron varias características de sus registros en el ClinicalTrials.gov, en los períodos de 2003 a 2007 y de 2009 a 2013. Se concluye que: a) la normativa promulgada por el CFM en 2008 fue ineficaz y prevaleció la posición adoptada por la Declaración de Helsinki; b) el patrocinio de ensayos con placebo por parte de la industria farmacéutica multinacional fue significativo; c) predominaron las investigaciones de fármacos para enfermedades crónicas, y fueron poco significativas para las enfermedades postergadas, de importancia para Brasil.

In 2008, Brazil's Federal Council of Medicine [Conselho Federal de Medicina] (CFM) - regulatory and supervisory agency on the ethical practice of medicine - banned the participation of Brazilian doctors in studies using placebos for diseases with efficient and effective treatment. This position differs with the Helsinki Declaration, which allows the use of placebos in methodologically justified conditions. To ascertain whether the CMF's ethical regulation modified the use of placebos in phase III clinical trials in Brazil, characteristics of the records in ClinicalTrials.gov were researched in the periods from 2003 to 2007 and from 2009 to 2013. The conclusions reached were: a) the regulations issued by the CFM in 2008 were ineffective and the position adopted by the Helsinki Declaration prevails; b) there was significant sponsorship by the multinational pharmaceutical industry of trials with placebos; c) the research was predominantly on new drugs for chronic diseases, with little study done of the neglected diseases which are of great importance to Brazil.

El uso de placebo en ensayos clínicos de fase III en Brasil / The use of placebos in phase III clinical trials in Brazil

El Consejo Federal de Medicina de Brasil (CFM) -órgano normativo y fiscalizador del ejercicio ético de la medicina- prohibió, en 2008, la participación de médicos brasileños en investigaciones que utilizaran placebo para enfermedades con tratamiento eficaz y efectivo, en contraposición a la Declaración de Helsinki, que permite su uso en condiciones metodológicamente justificadas. Con el objetivo de verificar si la normativa ética del CFM modificó el uso de placebo en ensayos clínicos de fase III en Brasil, se analizaron varias características de sus registros en el ClinicalTrials.gov, en los períodos de 2003 a 2007 y de 2009 a 2013. Se concluye que: a) la normativa promulgada por el CFM en 2008 fue ineficaz y prevaleció la posición adoptada por la Declaración de Helsinki; b) el patrocinio de ensayos con placebo por parte de la industria farmacéutica multinacional fue significativo; c) predominaron las investigaciones de fármacos para enfermedades crónicas, y fueron poco significativas para las enfermedades postergadas, de importancia para Brasil.(AU)

In 2008, Brazils Federal Council of Medicine [Conselho Federal de Medicina] (CFM) - regulatory and supervisory agency on the ethical practice of medicine - banned the participation of Brazilian doctors in studies using placebos for diseases with efficient and effective treatment. This position differs with the Helsinki Declaration, which allows the use of placebos in methodologically justified conditions. To ascertain whether the CMFs ethical regulation modified the use of placebos in phase III clinical trials in Brazil, characteristics of the records in ClinicalTrials.gov were researched in the periods from 2003 to 2007 and from 2009 to 2013. The conclusions reached were: a) the regulations issued by the CFM in 2008 were ineffective and the position adopted by the Helsinki Declaration prevails; b) there was significant sponsorship by the multinational pharmaceutical industry of trials with placebos; c) the research was predominantly on new drugs for chronic diseases, with little study done of the neglected diseases which are of great importance to Brazil.(AU)

Depletion of polysialic acid from neural cell adhesion molecule (PSA-NCAM) increases CA3 dendritic arborization and increases vulnerability to excitotoxicity.

Chronic immobilization stress (CIS) shortens apical dendritic trees of CA3 pyramidal neurons in the hippocampus of the male rat, and dendritic length may be a determinant of vulnerability to stress. Expression of the polysialylated form of neural cell adhesion molecule (PSA-NCAM) in the hippocampal formation is increased by stress, while PSA removal by Endo-neuraminidase-N (endo-N) is known to cause the mossy fibers to defasciculate and synapse ectopically in their CA3 target area. We show here that enzymatic removal of PSA produced a remarkable expansion of dendritic arbors of CA3 pyramidal neurons, with a lesser effect in CA1. This expansion eclipsed the CIS-induced shortening of CA3 dendrites, with the expanded dendrites of both no-stress-endo-N and CIS-endo-N rats being longer than those in no-stress-control rats and much longer than those in CIS-control rats. As predicted by the hypothesis that endo-N-induced dendritic expansion might increase vulnerability to excitotoxic challenge, systemic injection with kainic acid, showed markedly increased neuronal degeneration, as assessed by fluorojade B histochemistry, in rats that had been treated with endo-N compared to vehicle-treated rats throughout the entire hippocampal formation. PSA removal also exacerbated the CIS-induced reduction in body weight and abolished effects of CIS on NPY and NR2B mRNA levels. These findings support the hypothesis that CA3 arbor plasticity plays a protective role during prolonged stress and clarify the role of PSA-NCAM in stress-induced dendritic plasticity.

The inhibitory effect of acrylamide on NCAM expression in human neuroblastoma cells: involvement of CK2/Ikaros signaling pathway.

Acrylamide has been known to have a neurotoxic effect which is associated with nerve damage in both the central and peripheral nervous systems. Since neural cell adhesion molecule (NCAM) plays an important role in the processes of neuronal development and synaptic plasticity, the down-regulation of NCAM may lead impaired spatial memory and reduced long-term potentiation. We examined the effect of acrylamide on NCAM expression and the mechanisms of its effect in human neuroblastoma cells. Treatment with acrylamide resulted in the decrease of NCAM expression, which was reversed by CK2 inhibitor, 4,5,6,7-tetrabromobenzotriazole (TBB). Moreover, Western blot analysis showed that acrylamide induced the expression of CK2. Acrylamide dose-dependently decreased the DNA binding affinity of the Ikaros transcription factor, which is a bifunctional differentiation factor. In addition, the cells treated with acrylamide and CK2 inhibitor showed increased Ikaros activity compared with the acrylamide treatment only. Small interfering RNA-mediated depletion of CK2-α also increased Ikaros activity in acrylamide-treated cells. Overall, these data suggest that acrylamide decreases the Ikaros DNA binding activity via the CK2 pathway, resulting in a decrease of NCAM expression and provide further insight into the mechanisms underlying acrylamide actions.

[Flavonoids from Diospyros kaki inhibit the adhesion between lymphocyte and dorsal root ganglion].

OBJECTIVE: To investigate the effects of flavonoids from the leaves of Diospyros kaki L (FLDK) on the adhesion between the lymphocyte and the neurone. METHODS: Centrifugal assay for fluorescence-bsaed cell adhesion was used to assay the adhesion between the lymphocyte and the dorsal root ganglion (DRG). RESULTS: The adhesion was significantly suppressed in the presence of FLDK dose-dependently at 5, 25 microg/mL concentration. FLDK was also effective to inhibit the adhesion under the challenge of ICAM-1 by 28.5% and 50.1%, respectively. Furthermore, FLDK enforced the inhibition of anti-NCAM antibody on the lymphocyte adhesion to DRG cells. CONCLUSION: FLDK might contribute to the prevention and treatment of the inflammation injury under neuron insult such as ischemia/reperfusion, neurotrauma and other neurodegenerative disease by inhibiting the adhesion between lymphocytes and neurons.

A polysialic acid mimetic peptide promotes functional recovery in a mouse model of spinal cord injury.

Contrary to lower species that recapitulate some of the developmental programs, in mammals, functional recovery after spinal cord injury is impaired by a non-permissive environment and the lack of plasticity of adult neurons. The developmental plasticity associated linear homopolymer of alpha 2,8-linked sialic acid (PolySialic Acid, PSA), represents a permissive determinant that could contribute to recovery. We previously showed that a PSA cyclic mimetic peptide (PR-21) displayed PSA-like biological functions (Torregrossa, P., Buhl, L., Bancila, M., Durbec, P., Schafer, C., Schachner, M., Rougon, G., 2004. Selection of poly-alpha 2,8-sialic acid mimotopes from a random phage peptide library and analysis of their bioactivity. J. Biol. Chem. 279, 30707-30714.). In the present study we investigated the therapeutic potential of PR-21 in young adult mice after dorsal hemisection at the T9 level. We show that PR-21 fulfills several criteria for an in vivo use as it is not toxic, not immunogenic and displays good stability in biological fluids or tissue. Delivery of PR-21 to the lesion site decreased the time of the animals' return to continence, and enhanced motor functions, sensorimotor control and coordination of hindlimbs with forelimbs when compared to a control peptide. At the cellular level, PR-21 increased serotonergic axon density at and caudal to the lesion site, and decreased reactive gliosis in vivo. In an in vitro model of reactive astrocytes, PR-21 increased NCAM expression in strongly GFAP positive cells. Our data point to the unique features of a carbohydrate mimicking peptide, and support the notion that PSA can be considered as an important factor in recovery from spinal cord injury.

Cimetidine inhibits salivary gland tumor cell adhesion to neural cells and induces apoptosis by blocking NCAM expression.

BACKGROUND: Cimetidine, a histamine type-2 receptor antagonist, has been reported to inhibit the growth of glandular tumors such as colorectal cancer, however the mechanism of action underlying this effect is unknown. Adenoid cystic carcinoma is well known as a malignant salivary gland tumor which preferentially invades neural tissues. We demonstrated previously that human salivary gland tumor (HSG) cells spontaneously express neural cell adhesion molecule (NCAM), that HSG cell proliferation may be controlled via a homophilic (NCAM-NCAM) binding mechanism and that NCAM may be associated with perineural invasion by malignant salivary gland tumors. We further demonstrated that cimetidine inhibited NCAM expression and induced apoptosis in HSG cells. Here, we investigated the effects of cimetidine on growth and perineural/neural invasion of salivary gland tumor cells. METHODS: In this study, we have examined the effect of cimetidine on cancer cell adhesion to neural cells in vitro, one of the critical steps of cancer invasion and metastasis. We have also used an in vivo carcinogenesis model to confirm the effect of cimetidine. RESULTS: We have demonstrated for the first time that cimetidine can block the adhesion of HSG cells to neural cell monolayers and that it can also induce significant apoptosis in the tumor mass in a nude mouse model. We also demonstrated that these apoptotic effects of cimetidine might occur through down-regulation of the cell surface expression of NCAM on HSG cells. Cimetidine-mediated down-regulation of NCAM involved suppression of the nuclear translocation of NF-kappaB, a transcriptional activator of NCAM gene expression. CONCLUSION: These findings suggest that growth and perineural/neural invasion of salivary gland tumors can be blocked by administration of cimetidine via induction of apoptosis and in which NCAM plays a role.

Neurotrimin is an estrogen-regulated determinant of peripheral sympathetic innervation.

Mechanisms underlying axon degeneration in peripheral neuropathies and during normal remodeling are poorly understood. Because estrogen induces widespread sympathetic axon degeneration in female reproductive tract smooth muscle, we surveyed estrogen-regulated genes in rat myometrium. Microarray analysis revealed that the neural cell adhesion protein neurotrimin (Ntm) was markedly up-regulated 6 hr and down-regulated 24 hr after injection of 17beta-estradiol, and real time RT-PCR confirmed this pattern of expression. Protein analysis by Western blotting showed that uterine Ntm protein is also up-regulated in vivo 6-24 hr following estrogen injection and that Ntm protein is increased selectively in the myometrium during the high-estrogen phase of the estrous cycle. Cultured myometrial smooth muscle cells display perinuclear accumulations of Ntm protein, and 17beta-estradiol also increases intracellular levels of Ntm and its secretion into the culture medium. To determine if neurotrimin is required for estrogen-induced sympathetic pruning, sympathetic neurons were cocultured with uterine smooth muscle cells transfected with siRNA directed against Ntm. Although estrogen inhibited neurite outgrowth in nontransfected cocultures, estrogen's ability to reduce sympathetic outgrowth was impaired substantially following Ntm down-regulation. This supports a role for neurotrimin in mediating estrogen-induced sympathetic pruning in some peripheral targets. Together with earlier studies, these findings support the idea that physiological sympathetic axon degeneration is a multifactorial process requiring dynamic regulation of multiple repellant proteins.

Nrxn3 upregulation in the globus pallidus of mice developing cocaine addiction.

Dysfunctions affecting the connections of basal ganglia lead to major neurological and psychiatric disorders. We investigated levels of mRNA for three neurexins (Nrxn) and three neuroligins (Nlgn) in the globus pallidus, subthalamic nucleus, and substantia nigra, in control conditions and after short-term exposure to cocaine. The expression of Nrxn2beta and Nlgn3 in the substantia nigra and Nlgn1 in the subthalamic nucleus depended on genetic background. The development of short-term cocaine appetence induced an increase in Nrxn3beta expression in the globus pallidus. Human NRXN3 has recently been linked to several addictions. Thus, NRXN3 adhesion molecules may play an important role in the synaptic plasticity of neurons involved in the indirect pathways of basal ganglia, in which they regulate reward-related learning.

Cimetidine induces apoptosis of human salivary gland tumor cells.

It has been reported that cimetidine, a histamine type-2 receptor (H2R) antagonist, inhibits the growth of glandular tumors such as colorectal cancer. However, its effects against salivary gland tumors are still unknown. We demonstrated previously that human salivary gland tumor (HSG) cells spontaneously express the neural cell adhesion molecule (NCAM) and also that HSG cell proliferation could be controlled via a homophilic (NCAM-NCAM) binding mechanism and that NCAM may be associated with perineural invasion by malignant salivary gland tumors. In the present study, we investigated the effects of cimetidine via the expression of NCAM on tumor growth and perineural/neural invasion in salivary gland tumor cells. Expression of both NCAM mRNA and protein was found to decrease in a dose-dependent manner upon treatment with cimetidine for 24 h. The MTT assay and confocal laser microscopy clearly showed that HSG cells underwent apoptosis after treatment with cimetidine. Activation of caspases 3, 7, 8 and 9 was observed in HSG cells after cimetidine treatment, thus confirming that the apoptosis was induced by the activated caspases. Apaf-1 activity was also detected in HSG cells in a dose-dependent manner after treatment with cimetidine. We also found that the cimetidine-mediated down-regulation of NCAM expression in HSG cells did not occur via blocking of the histamine receptor, even though H2R expression was observed on HSG cells, as two other H2R antagonists, famotidine and ranitidine, did not show similar effects. We demonstrated for the first time that cimetidine can induce significant apoptosis of salivary gland tumor cells, which express NCAM, at least in part by down-regulation of NCAM expression on the cells. These findings suggest that the growth, development and perineural/neural invasion of salivary gland tumor cells can be blocked by cimetidine administration through down-regulation of NCAM expression, as well as induction of apoptosis.

Transforming growth factor beta1 and ethanol affect transcription and translation of genes and proteins for cell adhesion molecules in B104 neuroblastoma cells.

Transforming growth factor (TGF) beta1 and ethanol retard the migration of young, post-mitotic neurons to the developing cerebral cortex. The coordination of this migration depends upon cell adhesion proteins (CAPs). We examined the effects of TGFbeta1 and ethanol on genes related to both TGF and CAPs. Rat B104 neuroblastoma cells were treated with TGFbeta1 (0 or 10 ng/mL) and ethanol (0 or 400 mg/dL) for 6-48 h. Total RNA was purified from each sample and analyzed using the Rat U34A GeneChip (Affymetrix). Candidate genes were those up- or down-regulated by either TGFbeta1 or ethanol. Twenty transcripts of CAPs were identified as being expressed by B104 cells and as being affected by treatment with TGFbeta1 or ethanol. The expression was verified for five representative genes (neural cell adhesion molecule, L1, and integrins alpha1, alpha7, and beta1) using assays with real-time reverse transcriptase-polymerase chain reactions. Each of these genes showed time-dependent changes. The changes were reflected in increases in protein expression that appeared within 24 or 48 h. Thus, the effects of TGFbeta1 and ethanol on CAPs parallel changes described in vivo and likely underlie changes associated with ethanol-induced alterations in neuronal migration.

No effect of prolonged corticosterone over-exposure on NCAM, SGK1, and RGS4 mRNA expression in rat hippocampus.

Prolonged over-exposure of rats to corticosterone attenuates 5-HT(1A)-receptor-mediated responses in hippocampal CA1 cells through an unknown mechanism, not involving downregulation of 5-HT(1A) receptor expression. We here tested if corticosterone changes 5-HT(1A) receptor function indirectly, by altering hippocampal mRNA expression of NCAM, SGK1, or RGS4, which all modulate 5-HT(1A) receptor function. We found that the expression of none of these candidates was affected by corticosterone treatment.

Comparison of the impact of melatonin on chronic ethanol-induced learning and memory impairment between young and aged rats.

Chronic alcohol exposure causes functional and structural changes in nervous system which have all been associated with learning and memory impairments. Furthermore, alcohol consumption has been shown to alter the pattern of neural cell adhesion molecules (NCAM) which are involved in memory processes. In the current work, we investigated the effects of melatonin on learning and memory deficits induced by alcohol exposure in young and aged rats. A group of young rats (3 months old) were administered ethanol for 45 days and half of them were co-treated with melatonin. Similar treatments were performed in the aged (19 months old) rats. Morris water maze test and passive avoidance task were used to assess cognitive performance. Lipid peroxidation (LPO) and glutathione (GSH) levels were determined to characterize the level of oxidative stress in the hippocampus and cortex. NCAM levels were determined by Western blotting in the hippocampal homogenates. There was a significant elevation in LPO levels and a reduction in GSH levels in aged and alcohol-exposed rats. Furthermore, both young and aged rats displayed some cognitive impairment when given with alcohol for 45 days. Co-administration of melatonin with ethanol significantly reduced LPO and elevated GSH levels while improving the learning and memory deficits induced by ethanol; the aged rats exhibited a greater response to melatonin supplementation. Moreover, melatonin modulated NCAM expression in hippocampus. Present findings indicate that exposure to ethanol induces learning and memory deficits probably by generating reactive oxygen species and downregulating NCAM 180 in hippocampus of aged rats. Melatonin improves learning and memory deficits and the behavioral responses of rats to melatonin supplementation are age dependent.

Heme deficiency suppresses the expression of key neuronal genes and causes neuronal cell death.

Defective heme synthesis may cause acute porphyrias, which are associated with a wide array of neurological disturbances involving both the central and peripheral nervous systems. Thus, the understanding of the roles of heme in neuronal cell function may provide insights into the molecular events underlying the pathogenesis of neuropathies associated with defective heme synthesis. In this report, we use rat pheochromocytoma (PC12) clonal cells as a model system for studying the role of heme in neuronal cell survival. We examined the effects of inhibition of heme synthesis on signaling pathways and gene expression in nerve growth factor (NGF)-induced PC12 cells. We found that succinyl acetone-induced heme deficiency selectively caused apoptosis in NGF-induced PC12 cells. Further, we found that in succinyl acetone-treated, NGF-induced cells, the pro-survival Ras-ERK1/2 signaling pathway was inactivated and the pro-apoptotic JNK signaling pathway was activated. In these cells, the activation of caspase and the cleavage of nuclear poly (ADP-ribose) polymerase (PARP) were also evident. Importantly, microarray gene expression analysis showed that more than 20 key neuronal genes that were induced by NGF were suppressed by succinyl acetone. These genes include those encoding survival motor neuron protein, synaptic vesicle protein SVOP, and neural cell adhesion molecule NCAM. These results indicate that heme is important for neuronal cell signaling and the proper functioning of neuronal cells.

Neuroprotection mediated by subtoxic dose of NMDA in SH-SY5Y neuroblastoma cultures: activity-dependent regulation of PSA-NCAM expression.

The NMDA class of glutamate receptors plays a critical role in CNS, such as synaptic plasticity, axonal sprouting, growth, and migration. NMDA receptor stimulation has been shown to regulate polysialylated neural cell adhesion molecule (PSA-NCAM) expression in glial cell cultures and in hippocampal slice cultures. There is also growing evidence that molecular chaperons and ROS are related to the synaptic plasticity phenomena. We have examined the neuroprotective effect of subtoxic dose of NMDA in retinoic acid differentiated SH-SY5Y neuroblastoma cells. SH-SY5Y cell line differentiated with retinoic acid (10 muM) was exposed to NMDA (100 microM) or to antagonist MK-801 (200 nM) + NMDA and cells harvested after 24 h of treatment for PSA-NCAM, NCAM, and HSP70 expression study and for biochemical analysis. A significant increase was observed in PSA-NCAM, NCAM-180, NCAM-140, and HSP70 expression as seen by Western blotting and immunocytofluorescent studies in NMDA-treated cultures. Biochemical analysis revealed a significant increase in the activities of glutathione peroxidase (GPx) and copper zinc-superoxide dismutase (CuZnSOD) upon exposure to NMDA. No significant change was observed in the level of lipid peroxidation. All the changes observed reverted back to the control values upon pretreatment of cultures with MK-801, a non-competitive NMDA receptor antagonist, prior to NMDA exposure indicating the involvement of NMDA receptor in these changes. These results illustrate the neuroprotective role of subtoxic dose of NMDA in SH-SY5Y neuroblastoma cells.

Neural cell adhesion molecule function is regulated by metalloproteinase-mediated ectodomain release.

The neural cell adhesion molecule (NCAM) is involved in development of the nervous system, in brain plasticity associated with learning and memory, and in neuronal regeneration. NCAM regulates these processes by influencing cell adhesion, cell migration, and neurite outgrowth. NCAM activates intracellular signaling upon homophilic NCAM binding, and this is a prerequisite for NCAM-stimulated neurite outgrowth. NCAM is synthesized in three main membrane-bound isoforms, NCAM-120, NCAM-140, and NCAM-180. Soluble forms of NCAM in blood and cerebrospinal fluid have also been found, although the functional significance of these forms remains unclear. In this report, we demonstrate that NCAM can be released from primary hippocampal neurons in culture. The release was enhanced by application of ATP and inhibited by the metalloproteinase inhibitor BB-3103. ATP also induced metalloproteinase-dependent release of all three major NCAM isoforms from NCAM-transfected fibroblastoid L-cells. In this model system, the extracellular ATP-binding site of NCAM was shown not to be necessary for ATP-induced NCAM release. Furthermore, inhibition of serine, cysteine, and aspartic proteinases could not prevent ATP-induced down-regulation of NCAM in L-cells, suggesting that NCAM is cleaved directly by a metalloproteinase. Aggregation of hippocampal neurons in culture was increased in the presence of the metalloproteinase inhibitor GM 6001, consistent with a metalloproteinase-dependent shedding of NCAM occurring in these cells. Moreover, NCAM-dependent neurite outgrowth was significantly reduced by application of GM 6001. Taken together, these results suggest that membrane-bound NCAM can be cleaved extracellularly by a metalloproteinase and that metalloproteinase-dependent shedding of NCAM regulates NCAM-mediated neurite outgrowth.

Expression of cell adhesion molecules in the adriamycin-induced esophageal atresia rat model.

Cell adhesion molecules are well-known membrane glycoproteins widely expressed during embryonic development that play a crucial role in cell division, migration and differentiation. We investigated the cell-matrix relationship using N-CAM and pan-cadherin adhesion molecules in the adriamycin-induced esophageal atresia (EA) rat model in the hope of finding a clue to the mechanisms of this unique anomaly.Time-mated pregnant Sprague-Dawley rats were given either saline or adriamycin on days 8 and 9 of gestation. Embryos were harvested on the 18th day of gestation. Esophageal specimens obtained from adriamycin-exposed embryos with (EA+) or without esophageal atresia (EA-) and from saline-exposed embryos were immunostained with N-CAM and pan-cadherin primary antisera. The esophageal specimens from control and EA- groups revealed similar immunostaining properties: weak N-CAM and pan-cadherin immunoreactivity. In contrast, the EA+ group showed intense immunoreactivity. Our study demonstrated an increased synthesis of N-CAM and pan-cadherin in the epithelial cells of the atretic esophagus and trachea. These results suggest that embryonic cell-cell and cell-matrix interactions may play a crucial role in the development of adriamycin-induced EA.

Stress (hypothalamic-pituitary-adrenal axis) and pain response in male rats exposed lifelong to high vs. low phytoestrogen diets.

Estrogens exhibit complex but beneficial effects on brain structure, function and behavior. Soy-derived dietary phytoestrogens protect against hormone-dependent and age-related diseases, due to their estrogen-like hormonal actions. However, the effects of phytoestrogens on brain and behavior are relatively unknown. This study examined the influence of exposing male Long-Evans rats (lifelong) to either a phytoestrogen-rich (Phyto-600) or a phytoestrogen-free (Phyto-free) diet on body weights, behavioral pain thresholds, the hypothalamic-pituitary-adrenal (HPA) hormonal stress response, hippocampal glucocorticoid receptor and brain neural cell adhesion molecules (NCAM) and synaptophysin levels using standard behavioral and biochemical techniques. Body weights were significantly decreased in Phyto-600 fed animals compared to Phyto-free values. There were no significant changes in behavioral pain thresholds, circulating corticosterone concentrations (after acute immobilization stress) or NCAM and synaptophysin levels in various brain regions by the diet treatments. However, Phyto-600 fed males displayed significantly higher plasma adrenocorticotrophin (ACTH) (post-stress) and hippocampal glucocorticoid receptor levels vs. Phyto-free values. These data suggest that (1) body weights are significantly reduced by soy-derived phytoestrogens, (2) behavioral pain thresholds (via heat stimuli) are not influenced by dietary phytoestrogens, but (3) these estrogenic molecules in the hippocampus enhance glucocorticoid receptor abundance and alter the negative feedback of stress hormones towards a female-like pattern of higher ACTH release after activation of the HPA stress axis. This study is the first to show that lifelong consumption of dietary phytoestrogens alters the HPA stress response in male rats.

Mechanisms of brain injury: L1 cell adhesion molecule as a target for ethanol-induced prenatal brain injury.

The magnitude of the problem of neurodevelopmental disorders is enormous. Frequently, the mechanism of injury is unknown. In this article, the function of one cell adhesion molecule, L1, will be reviewed. L1 is critical for proper central nervous system development. Similarities between patients with fetal alcohol syndrome and with L1 mutations suggest that the mechanism of developmental neurotoxicity of ethanol is partly due to effects on L1 cell adhesion molecule.