Resveratrol exerts anti-oxidant and anti-inflammatory actions and prevents oxaliplatin-induced mechanical and thermal allodynia.

Chemotherapy-induced peripheral neuropathic pain (CIPNP) is a frequent and devastating side effect of cancer therapy. No preventive strategies are currently available. We investigated the use of resveratrol (RESV) in the prevention of CIPNP and evaluated key components of the antioxidant defense system and neuroinflammatory factors as possible mediators contributing to RESV actions. Male rats were injected with oxaliplatin (OXA) and received daily oral RESV. Paw mechanical and thermal allodynia, oxidative stress, antioxidant, pro-inflammatory and neuronal injury/activation markers were evaluated in the sciatic nerve (SN), lumbar dorsal root ganglia (DRG) and spinal cord (SC). OXA-injected animals developed mechanical and thermal allodynia, while those receiving OXA + RESV showed patterns of response similar to control animals. Higher TBARS levels and lower GSH/GSSG ratios were observed in the SN of animals receiving OXA. The mRNA levels of the transcription factor NFκB and the pro-inflammatory cytokine TNFα were found to be upregulated both in lumbar DRG and SC. In addition, the antioxidant enzymes NQO-1 and HO-1 and the neuronal injury marker ATF3 showed increased levels of expression in lumbar DRG. In the dorsal SC the neuronal activation marker c-fos and the transcription factor Nrf2, main regulator of antioxidant defenses, were found to be upregulated. RESV early and sustained administration prevented NFκB, TNFα, ATF3 and c-fos upregulation, while increasing the expression of Nrf2, NQO-1, HO-1 and the redox-sensitive deacetylase SIRT1. RESV treatment was also able to restore TBARS levels and GSH/GSSG ratio. Thus, RESV administration resulted in the upregulation of antioxidant mediators, suppression of pro-inflammatory parameters and prevention of OXA-induced mechanical and thermal allodynia.

Prototipo de Silla de Ruedas Dirigida Usando Parpadeos / A Wheel Chair Prototype Moved by means of Eye Blinks

Resumen El presente trabajo describe un prototipo de una silla de ruedas que es dirigido hacia enfrente y hacia atrás usando 2 o 3 parpadeos, respectivamente, y es detenido cuando se alcanzan ciertos niveles de atención. El objetivo principal es que las personas que tienen discapacidad motora en sus extremidades puedan usarlo para desplazarse y les brinde autonomía. Para captar la señal de los parpadeos, se utilizó la diadema MindWave Mobile de Neurosky. Se implementó un circuito electrónico en conjunto con Arduino que permite complementar la ejecución del accionamiento del prototipo. El prototipo se probó con 10 personas cuyas edades oscilan entre 20 y 35 años. Los resultados muestran que, en un 80% de los casos, el prototipo se mueve correctamente. La gran ventaja del presente trabajo es que la interfaz cerebro-computadora con la que cuenta este prototipo no requiere entrenamiento previo del sistema, por lo cual, puede ser usado por cualquier persona. Además, su costo es más accesible comparado con otros dispositivos para el mismo fin.

Abstract The present work describes a prototype of a wheel chair directed by means of eye blinks, which can be moved forwards, and backwards using 2 or 3 eye blinks, respectively, and stopped when a certain attention level is met. The main objective of this work is to help people, who have motor disabilities on their arms and legs, move and have autonomy. In order to register the eye blinking signals, the MindWave Mobile device from Neurosky was used. Moreover, an electronic circuit in combination with Arduino has been used to make the prototype work. This prototype has been tested in 10 healthy people from 20 to 35 years old. According to the results, in 80% of the cases the prototype worked correctly. The main advantage of the present work is that the brain-computer interface, which is part of the prototype, does not require training, and hence, it could be used by most of the people. Moreover, its cost is less than similar devices.

Progesterone reduces the expression of spinal cyclooxygenase-2 and inducible nitric oxide synthase and prevents allodynia in a rat model of central neuropathic pain.

BACKGROUND: Spinal cord injury (SCI) results in the development of chronic pain that is refractory to conventional treatment. Progesterone, a neuroprotective steroid, may offer a promising perspective in pain modulation after central injury. Here, we explore the impact of progesterone administration on the post-injury inflammatory cascade involving the enzymes cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) at the spinal cord level. We also analyse pain behaviours, the profile of glial cell activation, and IκB-α mRNA levels, as an index of NF-κB transactivation. METHODS: We used biochemical, immunohistochemical and molecular techniques, as well as behavioural studies, to investigate the effects of progesterone in a well-characterized model of central neuropathic pain. RESULTS: Injured animals receiving progesterone presented reduced mRNA levels of the proinflammatory enzymes, as well as decreased COX-2 activity and nitrite levels, as compared to vehicle-treated injured rats. Further, animals receiving the steroid exhibited lower levels of IκB-α mRNA, suggesting decreased NF-κB transactivation. Progesterone administration also attenuated the injury-induced increase in the number of glial fibrillary acidic protein and OX-42 positive cells both at early and late time points after injury, and prevented the development of mechanical and thermal allodynia. Further, when injured rats received early progesterone administration for a critical period of time after injury, they did not display allodynic behaviours even after the treatment had stopped. CONCLUSIONS: Our results suggest that progesterone, by modulating early neuroinflammatory events triggered after SCI, may represent a useful strategy to prevent the development of central chronic pain.

Contribution of the residual body in the spatial organization of Toxoplasma gondii tachyzoites within the parasitophorous vacuole.

Toxoplasma gondii proliferates and organizes within a parasitophorous vacuole in rosettes around a residual body and is surrounded by a membranous nanotubular network whose function remains unclear. Here, we characterized structure and function of the residual body in intracellular tachyzoites of the RH strain. Our data showed the residual body as a body limited by a membrane formed during proliferation of tachyzoites probably through the secretion of components and a pinching event of the membrane at the posterior end. It contributes in the intravacuolar parasite organization by the membrane connection between the tachyzoites posterior end and the residual body membrane to give place to the rosette conformation. Radial distribution of parasites in rosettes favors an efficient exteriorization. Absence of the network and presence of atypical residual bodies in a ΔGRA2-HXGPRT knock-out mutant affected the intravacuolar organization of tachyzoites and their exteriorization.

Membrane progesterone receptors localization in the mouse spinal cord.

The recent molecular cloning of membrane receptors for progesterone (mPRs) has tremendous implications for understanding the multiple actions of the hormone in the nervous system. The three isoforms which have been cloned from several species, mPRalpha, mPRbeta and mPRgamma, have seven-transmembrane domains, are G protein-coupled and may thus account for the rapid modulation of many intracellular signaling cascades by progesterone. However, in order to elucidate the precise functions of mPRs within the nervous system it is first necessary to determine their expression patterns and also to develop new pharmacological and molecular tools. The aim of the present study was to profile mPR expression in the mouse spinal cord, where progesterone has been shown to exert pleiotropic actions on neurons and glial cells, and where the hormone can also be locally synthesized. Our results show a wide distribution of mPRalpha, which is expressed in most neurons, astrocytes, oligodendrocytes, and also in a large proportion of NG2(+) progenitor cells. This mPR isoform is thus likely to play a major role in the neuroprotective and promyelinating effects of progesterone. On the contrary, mPRbeta showed a more restricted distribution, and was mainly present in ventral horn motoneurons and in neurites, consistent with an important role in neuronal transmission and plasticity. Interestingly, mPRbeta was not present in glial cells. These observations suggest that the two mPR isoforms mediate distinct and specific functions of progesterone in the spinal cord. A significant observation was their very stable expression, which was similar in both sexes and not influenced by the presence or absence of the classical progesterone receptors. Although mPRgamma mRNA could be detected in spinal cord tissue by reverse transcriptase-polymerase chain reaction (RT-PCR), in situ hybridization analysis did not allow us to verify and to map its presence, probably due to its relatively low expression. The present study is the first precise map of the regional and cellular distribution of mPR expression in the nervous system, a prior requirement for in vivo molecular and pharmacological strategies aimed to elucidate their precise functions. It thus represents a first important step towards a new understanding of progesterone actions in the nervous system within a precise neuroanatomical context.

The membrane-associated progesterone-binding protein 25-Dx: expression, cellular localization and up-regulation after brain and spinal cord injuries.

Progesterone has neuroprotective effects in the injured and diseased spinal cord and after traumatic brain injury (TBI). In addition to intracellular progesterone receptors (PR), membrane-binding sites of progesterone may be involved in neuroprotection. A first putative membrane receptor of progesterone, distinct from the classical intracellular PR isoforms, with a single membrane-spanning domain, has been cloned from porcine liver. Homologous proteins were cloned in rats (25-Dx), mice (PGRMC1) and humans (Hpr.6). We will refer to this progesterone-binding protein as 25-Dx. The distribution and regulation of 25-Dx in the nervous system may provide some clues to its functions. In spinal cord, 25-Dx is localized in cell membranes of dorsal horn neurons and ependymal cells lining the central canal. A role of 25-Dx in mediating the protective effects of progesterone in the spinal cord is supported by the observation that its mRNA and protein are up-regulated by progesterone in dorsal horn of the injured spinal cord. In contrast, the classical intracellular PRs were down-regulated under these conditions. In brain, 25-Dx is particularly abundant in the hypothalamic area, circumventricular organs, ependymal cells of the ventricular walls, and the meninges. Interestingly, it is co-expressed with vasopressin in neurons of the paraventricular, supraoptic and retrochiasmatic nuclei. In response to TBI, 25-Dx expression is up-regulated in neurons and induced in astrocytes. The expression of 25-Dx in structures involved in cerebrospinal fluid production and osmoregulation, and its up-regulation after brain damage, point to a potentially important role of this progesterone-binding protein in the maintenance of water homeostasis after TBI. Our observations suggest that progesterone's actions may involve different signaling mechanisms depending on the pathophysiological context, and that 25-Dx may be involved in the neuroprotective effect of progesterone in the injured brain and spinal cord.

Progesterone up-regulates neuronal brain-derived neurotrophic factor expression in the injured spinal cord.

Progesterone (PROG) provides neuroprotection to the injured central and peripheral nervous system. These effects may be due to regulation of myelin synthesis in glial cells and also to direct actions on neuronal function. Recent studies point to neurotrophins as possible mediators of hormone action. Here, we show that the expression of brain-derived neurotrophic factor (BDNF) at both the mRNA and protein levels was increased by PROG treatment in ventral horn motoneurons from rats with spinal cord injury (SCI). Semiquantitative in situ hybridization revealed that SCI reduced BDNF mRNA levels by 50% in spinal motoneurons (control: 53.5+/-7.5 grains/mm(2) vs. SCI: 27.5+/-1.2, P<0.05), while PROG administration to injured rats (4 mg/kg/day during 3 days, s.c.) elicited a three-fold increase in grain density (SCI+PROG: 77.8+/-8.3 grains/mm(2), P<0.001 vs. SCI). In addition, PROG enhanced BDNF immunoreactivity in motoneurons of the lesioned spinal cord. Analysis of the frequency distribution of immunoreactive densities (chi(2): 812.73, P<0.0001) showed that 70% of SCI+PROG motoneurons scored as dark stained whereas only 6% of neurons in the SCI group belonged to this density score category (P<0.001). PROG also prevented the lesion-induced chromatolytic degeneration of spinal cord motoneurons as determined by Nissl staining. In the normal intact spinal cord, PROG significantly increased BDNF inmunoreactivity in ventral horn neurons, without changes in mRNA levels. Our findings suggest that PROG enhancement of endogenous neuronal BDNF could provide a trophic environment within the lesioned spinal cord and might be part of the PROG activated-pathways to provide neuroprotection.

Effects of injury and progesterone treatment on progesterone receptor and progesterone binding protein 25-Dx expression in the rat spinal cord.

Progesterone provides neuroprotection after spinal cord injury, but the molecular mechanisms involved in this effect are not completely understood. In this work, expression of two binding proteins for progesterone was studied in intact and injured rat spinal cord: the classical intracellular progesterone receptor (PR) and 25-Dx, a recently discovered progesterone membrane binding site. RT-PCR was employed to determine their relative mRNA levels, whereas cellular localization and relative protein levels were investigated by immunocytochemistry. We observed that spinal cord PR mRNA was not up-regulated by estrogen in contrast to what is observed in many brain areas and in the uterus, but was abundant as it amounted to a third of that measured in the estradiol-stimulated uterus. In male rats with complete spinal cord transection, levels of PR mRNA were significantly decreased, while those of 25-Dx mRNA remained unchanged with respect to control animals. When spinal cord-injured animals received progesterone treatment during 72 h, PR mRNA levels were not affected and remained low, whereas 25-Dx mRNA levels were significantly increased. Immunostaining of PR showed its intracellular localization in both neurons and glial cells, whereas 25-Dx immunoreactivity was localized to cell membranes of dorsal horn and central canal neurons. As the two binding proteins for progesterone differ with respect to their response to lesion, their regulation by progesterone, their cellular and subcellular localizations, their functions may differ under normal and pathological conditions. These observations point to a novel and potentially important role of the progesterone binding protein 25-Dx after injury of the nervous system and suggest that the neuroprotective effects of progesterone may not necessarily be mediated by the classical progesterone receptor but may involve distinct membrane binding sites.

Biological activities and molecular targets of the human papillomavirus E7 oncoprotein.

The human papillomavirus (HPV) E7 protein is one of only two viral proteins that remain expressed in HPV-associated human cancers. HPV E7 proteins share structural and functional similarities with oncoproteins encoded by other small DNA tumor viruses such as adenovirus E1A and SV40 large tumor antigen. The HPV E7 protein plays an important role in the viral life cycle by subverting the tight link between cellular differentiation and proliferation in normal epithelium, thus allowing the virus to replicate in differentiating epithelial cells that would have normally withdrawn from the cell division cycle. The transforming activities of E7 largely reflect this important function.

Cellular basis of steroid neuroprotection in the wobbler mouse, a genetic model of motoneuron disease.

1. The Wobbler mouse suffers an autosomal recessive mutation producing severe motoneuron degeneration and astrogliosis in the spinal cord. It has been considered a suitable model of human motoneuron disease, including the sporadic form of amyotrophic lateral sclerosis (ALS). 2. Evidences exist demonstrating increased oxidative stress in the spinal cord of Wobbler mice, whereas antioxidant therapy delayed neurodegeneration and improved muscle trophism. 21-Aminosteroids are glucocorticoid-derived hydrophobic compounds with antioxidant potency 3 times higher than vitamin E and 100 times higher than methylprednisolone. They do not bind to intracellular receptors, and prevent lipid peroxidation by insertion into membrane lipid bilayers. 3. In common with the spinal cord of ALS patients, Wobbler mice present astrocytosis with hyperexpression of glial fibrillary acidic protein (GFAP), and increased expression of nitric oxide synthase (NOS) and growth-associated protein (GAP-43) in motoneurons. Here, we review our studies on the effects of a 21-aminosteroid on GFAP, NOS, and GAP-43. 4. First, we showed that 21-aminosteroid treatment further increased GFAP-expressing astrocytes in gray matter of the Wobbler spinal cord. This effect may provide neuroprotection if one considers a trophic and beneficial function of astrocytes during the course of degeneration. Other neuroprotectans used in Wobbler mice (T-588) also increased pre-existing astrocytosis. 5. Second, histochemical determination of NADPH-diaphorase, a parameter indicative of neuronal NOS activity, showed that the 21-aminosteroid down-regulated the high activity of this enzyme in ventral horn motoneurons. Therefore, suppression of nitric oxide by decreasing NADPH-diaphorase (NOS) activity may provide neuroprotection considering that excess NO is highly toxic to motoneurons. 6. Finally, 21-aminosteroid treatment significantly attenuated the aberrant expression of both GAP-43 protein and mRNA in Wobbler motoneurons. Hyperexpression of GAP-43 possibly indicated abnormal synaptogenesis, denervation, and muscle atrophy, parameters which may return to normal following antioxidant steroid treatment. 7. Besides 21-aminosteroids, other steroids also behave as neuroprotectans. In this regard, degenerative diseases may constitute potential targets of these hormones, based on the fact that the spinal cord expresses in a regional and cell-specific fashion, receptors for androgens. progesterone, adrenal steroids, and estrogens.

Diabetes increases the expression of hypothalamic neuropeptides in a spontaneous model of type I diabetes, the nonobese diabetic (NOD) mouse.

1. Synthesis of oxytocin (OT) and arginine-vasopressin (AVP) is increased in induced models of Type I diabetes, such as the streptozotocin model. However, these parameters have not yet been evaluated in spontaneous models, such as the nonobese diabetic mouse (NOD). Therefore, we studied in the magnocellular cells of the paraventricular nucleus (PVN) of nondiabetic and diabetic 16-week-old female NOD mice and control C57B1/6 mice, the immunocytochemistry of OT and AVP peptides and their mRNA expression, using nonisotopic in situ hybridization (ISH). 2. In nondiabetic and diabetic NOD female mice, the number of OT- and AVP-immunoreactive cells were similar to those of the controls, whereas immunoreaction intensity was significantly higher for both peptides in diabetic NOD as compared with nondiabetic NOD and control C57B1/6 mice. 3. ISH analysis showed that the number of OT mRNA-containing cells was in the same range in the three groups, whereas higher number of AVP mRNA expressing cells was found in diabetic NOD mice. However, the intensity of hybridization signal was also higher for both OT and AVP mRNA in the diabetic group as compared with nondiabetic NOD and control mice. 4. Blood chemistry demonstrated that haematrocrit, total plasma proteins, urea, sodium, and potassium were within normal limits in diabetic mice. Thus, NOD mice were neither hypernatremic nor dehydrated. 5. We suggest that upregulation of OT and AVP reflects a high-stress condition in the NOD mice. Diabetes may affect neuropeptide-producing cells of the PVN, with the increased AVP and OT playing a deleterious role on the outcome of the disease.

Degradation of the retinoblastoma tumor suppressor by the human papillomavirus type 16 E7 oncoprotein is important for functional inactivation and is separable from proteasomal degradation of E7.

The steady-state level and metabolic half-life of retinoblastoma tumor suppressor protein pRB are decreased in cells that express high-risk human papillomavirus (HPV) E7 proteins. Here we show that pRB degradation is a direct activity of E7 and does not reflect a property of cell lines acquired during the selection process for E7 expression. An amino-terminal domain of E7 that does not directly contribute to pRB binding but is required for transformation is also necessary for E7-mediated pRB degradation. Treatment with inhibitors of the 26S proteasome not only blocks E7-mediated pRB degradation but also causes the stabilization of E7. Mutagenic analyses, however, reveal that the processes of proteasomal degradation of E7 and pRB are not linked processes. HPV type 16 E7 also targets the pRB-related proteins p107 and p130 for destabilization by a proteasome-dependent mechanism. Using the SAOS2 flat-cell assay as a biological indicator for pRB function, we demonstrate that pRB degradation, not solely binding, is important for the E7-induced inactivation of pRB.

Visually induced activity in human frontal motor areas during simple visuomotor performance.

Visuomotor tasks elicit neuronal activity in primate motor areas at relatively short latencies. Although this early activity embodies features of visual responses (short latency, stimulus-dependency), its sensory nature has been questioned. We investigated neural correlates of visuomotor performance in human motor areas using scalp and intracranial event-related potential measures. A simple visuomanual reaction-time task evoked early potentials at 133-145 ms post-stimulus which occurred much earlier than the motor potentials of the same region. The amplitude of the early potentials covaried with stimulus location and was independent of parameters of the motor response. Because of their timing, stimulus-dependency and characteristics of our behavioral task, the early potentials are suggested to reflect neuronal responses of sensory nature rather than processing related to pure motor aspects of the task.

Glucocorticoid regulation of motoneuronal parameters in rats with spinal cord injury.

1. Glucocorticoids exert beneficial effects after acute CNS injury in humans and experimental animals. To elucidate potential mechanisms of glucocorticoid action in the lesioned spinal cord, we have studied if treatment with dexamethasone (DEX) modulated the neurotrophin binding receptor p75 (p75NTR) and choline acetyltransferase (ChAT), a marker of neuronal functional viability. 2. Rats with a sham operation or with spinal cord transection at the thoracic level received vehicle or DEX several times postlesion and were sacrificed 48 hr after surgery. The lumbar region caudal to the lesion was processed for p75NTR and ChAT immunoreactivity (IR) using quantitative densitometric analysis. 3. We observed that p75NTR-IR was absent from ventral horn motoneurons of sham-operated rats, in contrast to strong staining of neuronal perikaryon in TRX rats. Administration of DEX to TRX rats had no effect on the number of neuronal cell bodies expressing p75NTR-IR but significantly increased the number and length of immunostained neuronal processes. 4. Furthermore, spinal cord transection reduced ChAT immunostaining of motoneurons by 50%, whereas DEX treatment reverted this pattern to cells with a strong immunoreaction intensity in perikaryon and cell processes. 5. It is hypothesized that increased expression of p75NTR in cell processes and of ChAT in motoneurons may be part of a mechanism by which glucocorticoids afford neuroprotection, in addition to their known antiinflammatory effects.

The 21-aminosteroid U-74389F attenuates hyperexpression of GAP-43 and NADPH-diaphorase in the spinal cord of wobbler mouse, a model for amyotrophic lateral sclerosis.

The wobbler mouse suffers an autosomal recessive mutation producing severe neurodegeneration and astrogliosis in spinal cord. It has been considered a model for amyotrophic lateral sclerosis. We have studied in these animals the expression of two proteins, the growth-associated protein (GAP-43) and the NADPH-diaphorase, the nitric oxide synthesizing enzyme, employing immunocytochemistry and histochemistry. We found higher expression of GAP-43 immunoreactivity in dorsal horn, Lamina X, corticospinal tract and ventral horn motoneurons in wobbler mice compared to controls. Weak NADPH-diaphorase activity was present in control motoneurons, in contrast to intense labeling of the wobbler group. No differences in diaphorase activity was measured in the rest of the spinal cord between control and mutant mice. A group of animals received subcutaneously for 4 days a 50 mg pellet of U-74389F, a glucocorticoid-derived 21-aminosteroid with antioxidant properties but without glucocorticoid activity. U-74389F slightly attenuated GAP-43 immunostaining in dorsal regions of the spinal cord from wobblers but not in controls. However, in motoneurons of wobbler mice number of GAP-43 immunopositive neurons, cell processes and reaction intensity were reduced by U-74389F. The aminosteroid reduced by 50% motoneuron NADPH-diaphorase activity. Hyperexpression of GAP-43 immunoreactivity in wobbler mice may represent an exaggerated neuronal response to advancing degeneration or muscle denervation. It may also be linked to increased nitric oxide levels. U-74389F may stop neurodegeneration and/or increase muscle trophism and stop oxidative stress, consequently GAP-43 hyperexpression was attenuated. Wobbler mice may be important models to evaluate the use of antioxidant steroid therapy with a view to its use in human motoneuron disease.

Regulation of gene expression by corticoid hormones in the brain and spinal cord.

Glucocorticoids (GC) and mineralocorticoids (MC) have profound regulatory effects upon the central nervous system (CNS). Hormonal regulation affects several molecules essential to CNS function. First, evidences are presented that mRNA expression of the alpha3 and beta1-subunits of the Na,K-ATPase are increased by GC and physiological doses of MC in a region-dependent manner. Instead, high MC doses reduce the beta1 isoform and enzyme activity in amygdaloid and hypothalamic nuclei, an effect which may be related to MC control of salt appetite. The alpha3-subunit mRNA of the Na,K-ATPase is also stimulated by GC in motoneurons of the injured spinal cord, suggesting a role for the enzyme in GC neuroprotection. Second, we provide evidences for hormonal effects on the expression of mRNA for the neuropeptide arginine vasopressin (AVP). Our data show that GC inhibition of AVP mRNA levels in the paraventricular nucleus is sex-hormone dependent. This sexual dimorphism may explain sex differences in the hypothalamic-pituitary-adrenal axis function between female and male rats. Third, steroid effects on the astrocyte marker glial fibrillary acidic protein (GFAP) points to a complex regulatory mechanism. In an animal model of neurodegeneration (the Wobbler mouse) showing pronounced astrogliosis of the spinal cord, in vivo GC treatment down-regulated GFAP immunoreactivity, whereas the membrane-active steroid antioxidant U-74389F up-regulated this protein. It is likely that variations in GFAP protein expression affect spinal cord neurodegeneration in Wobbler mice. Fourth, an interaction between neurotrophins and GC is shown in the injured rat spinal cord. In this model, intensive GC treatment increases immunoreactive low affinity nerve growth factor (NGF) receptor in motoneuron processes. Because GC also increases immunoreactive NGF, this mechanism would support trophism and regeneration in damaged tissues. In conclusion, evidences show that some molecules regulated by adrenal steroids in neurons and glial cells are not only involved in physiological control, but additionally, may play important roles in neuropathology.

[A retrospective study of patients with epidemic optic neuropathy in a health area]. / Estudio retrospectivo de los pacientes con neuropatía óptica epidémica en un área de salud.

The sample of 104 patients who were diagnosed optic epidemic neuropathy at the health area of the "Rampa" Polyclinic in 1993 was reviewed. 50 of them were studied again. Visual acuity as well as the sensitivity to contrast by the Pelli Robson's method were explored. Ishihara's color-vision test was applied and an ophthalmological examination including fundus of the eye was made. All this was done by a group of experts who were searching temporary papillary paleness or lost of the bundles of papillomacular fibres, which are the diagnostic elements of the disease even in those cases that recover vision. 21 (42%) of the 50 studied patients fulfilled the criteria established for these cases by the Ministry of Public Health concerning visual acuity and color vision to diagnose optic epidemic neuropathy, although only 14 (28%) were ratified as cases. The typical alterations of the fundus of the eye were described, confirming the diagnosis. Cases were classified according to the initial state of visual acuity and to evolution. 3 had had an affectation of the visual acuity of 0.1 or worse (severe), and only one patient had a mild affectation with 0.8 of vision. The rest ranged between 0.2 and 0.6. Only one patient had a serious sequela. The low percentage of cases ratified as optic epidemic neuropathy does not represent what happened in the whole country, but it may be considered as a pattern of what took place at those units with the same conditions during the peak of the epidemic.

Zinc uptake in five sectors of the rat gastrointestinal tract: kinetic study in the whole colon.

PURPOSE: The uptake of zinc as acexamic acid salt in the rat gastrointestinal tract, using an in situ static technique, was studied. Our aim was to investigate an absorption window for zinc and the uptake kinetics in the colon. METHODS: To detect selectivity phenomena in zinc absorption, buffered saline solutions of zinc (50 micrograms/ ml) were perfused in stomach, whole colon and three 33-cm fractions of the small intestine (proximal, middle and distal segments). To characterize zinc uptake kinetics in whole colon, five different zinc concentrations (5, 25, 50, 150 y 250 micrograms/ml) were assayed. Zinc secreted into the gastrointestinal tract during the experiments was deducted from the uptake. RESULTS: Zinc secretion was characterized as an apparent zero-order process for all the studied segments (mean secretion rate = 0.10 +/- 0.03 microgram/(ml x min)). The stomach exhibited little ability to absorb zinc (apparent first order rate constant = 0.17 +/- 0.07 h-1), whereas the highest transport rates were found in the last two thirds of the small intestine and colon (first order constants: 0.66 +/- 0.13 h-1, 1.00 +/- 0.06 h-1, 0.97 +/- 0.14 h-1, 0.96 +/- 0.19 h-1 for proximal, middle, distal and colon segments, respectively). Zinc uptake in the colon was characterized by means of a Michaelis-Menten and first-order combined kinetics, with the following parameters: Vm = 0.36 +/- 0.02 microgram/(ml x min), Km = 18.01 +/- 0.40 microgram /ml and Ka = 0.40 +/- 0.01 h-1. CONCLUSIONS: Zinc is preferably absorbed in the middle and distal parts of the rat gastrointestinal tract. In the colon a saturable mechanism may be involved in apparent absorption.

The 21-aminosteroid U-74389F increases the number of glial fibrillary acidic protein-expressing astrocytes in the spinal cord of control and Wobbler mice.

1. Wobbler mice suffer an autosomal recessive mutation producing severe motoneuron degeneration and dense astrogliosis, with increased levels of glial fibrillary acidic protein (GFAP) in the spinal cord and brain stem. They have been considered animal models of amyotrophic lateral sclerosis and infantile spinal muscular atrophy. 2. Using Wobbler mice and normal littermates, we investigated the effects of the membrane-active steroid Lazaroid U-74389F on the number of GFAP-expressing astrocytes and glucocorticoid receptors (GR). Lazaroids are inhibitors of oxygen radical-induced lipid peroxidation, and proved beneficial in cases of CNS injury and ischemia. 3. Four days after pellet implantation of U-74389F into Wobbler mice, hyperplasia and hypertophy of GFAP-expressing astrocytes were apparent in the spinal cord ventral and dorsal horn, areas showing already intense astrogliosis in untreated Wobbler mice. In control mice, U-74389F also produced astrocyte hyperplasia and hypertophy in the dorsal horn and hyperplasia in the ventral-lateral funiculi of the cord. 4. Given in vivo U-74389F did not change GR in spinal cord of Wobbler or control mice, in line with the concept that it is active in membranes but does not bind to GR. Besides, U-74390F did not compete for [3H]dexamethasone binding when added in vitro. 5. The results suggest that stimulation of proliferation and size of GFAP-expressing astrocytes by U-74389F may be a novel mechanism of action of this compound. The Wobbler mouse may be a valuable animal model for further pharmacological testing of glucocorticoid and nonglucocorticoid steroids in neurodegenerative diseases.