Search

BACKGROUND/AIMS An altered growth hormone/insulin-like growth factor-I (GH/IGF-I) axis occurs in advanced liver cirrhosis, characterised by diminished serum levels of IGF-I and increased concentrations of GH. Under normal conditions, GH release is mediated by somatostatin (SS) inhibition. However, the influence of SS on GH release in cirrhosis is not well known. IGF-I supplementation has beneficial effects in experimental cirrhosis, and - under physiological conditions - IGF-I increases SS, inhibiting GH. The aims of this work were to study SS tone in cirrhotic animals and to evaluate whether IGF-I treatment influences SS tone, controlling GH secretion in cirrhosis. METHODS We studied the influence of SS on GH secretion by assessing GH response to pyridostigmine (PD) in cirrhotic rats treated and untreated with IGF-I. Liver cirrhosis was induced with CCl4-inhalation for 11 weeks in male Wistar rats. The animals were randomly divided into two groups: CI+IGF (n=12), which received IGF-I treatment for 12 days (2 microg/100 g body wt-1 x d-1) and CI (n=12), which received saline. Healthy controls (CO, n=12) were studied at the same time. On day 13, animals from each group were subdivided into two groups (n=6) in order to explore the effect of a PD intrajugular bolus (10 microg x 100 gbw-1) on serum GH levels (at 0,10,20,30 and 60 min), which were assessed by RIA. RESULTS PD bolus did not exert any effect on GH serum levels in the CI group, suggesting a low SS tone in cirrhotic rats. However, PD induced an increase in GH levels into CO and CI+IGF groups. In conclusion, as occurs under normal conditions, the cholinergic system is a significant modulator of GH secretion in experimental liver cirrhosis. CONCLUSION Cirrhotic rats have a reduced somatostatinergic tone which can be restored by IGF-I supplementation, suggesting that somatostatin is the main factor involved in the feed-back regulation between GH and IGF-I in cirrhosis.

The objective of this study is to describe the frequency and severity of behavioral and psychological symptoms (BPS) in a group of 125 patients diagnosed of Alzheimer's disease (AD) (DSM-IV-TR and NINCDSADRDA criteria).The evaluation of the BPS was carried out using the Neuropsychiatric Inventory (NPI; Cummings et al., 1994). The sociodemographic and personal background data of the patients were gathered and the dementia stage was established with the Global Deterioration Scale (GDS Reisberg, 1982).A total of 122 patients (98%) presented BPS, with an average of five symptoms per patient. Frequency of presentation was the following: apathy (75%), irritability (66%), depression (60%), agitation (55%), anxiety (54%), aberrant motor activity (47%), delirium (38%), sleeping disorders (36%), disinhibition (29%), eating disorders (28%), hallucinations (20%) and euphoria (4%).These results show the high incidence of BPS in AD patients and point to the necessity and importance of treating these disorders appropriately.

We studied the distribution of calbindin-immunoreactive fibers and cell bodies in the cat brainstem. The densest clusters of immunoreactive perikarya were found in the inferior and superior colliculi, the inferior olive, the periaqueductal gray, the central tegmental field and the substantia nigra, whereas the central linear nucleus, the locus coeruleus, the nucleus incertus, the dorsal and ventral nuclei of the lateral lemniscus, the cuneiform nucleus, the pontine gray, the Kölliker-Fuse nucleus, the dorsal motor nucleus of the vagus and the medial nucleus of the solitary tract had the lowest density. In the lateral tegmental field, the marginal nucleus of the brachium conjunctivum, the superior central nucleus, the nucleus sagulum, the dorsal nucleus of the raphe, the interpeduncular nucleus and the retrorubral nucleus the density of immunoreactive cell bodies was moderate. A high density of immunoreactive fibers was observed in the substantia nigra, the nucleus ruber, the superior and inferior colliculi, the periaqueductal gray, the interpeduncular nucleus, the central, magnocellular and lateral tegmental fields, the marginal nucleus of the brachium conjunctivum, the postpyramidal nucleus of the raphe, the inferior olive, the internal division of the lateral reticular nucleus and the medial and lateral nuclei of the superior olive. A moderate density of calbindin-immunoreactive fibers was found in the retrorubral nucleus, the central linear nucleus, the locus coeruleus, the nucleus sagulum, the dorsal nucleus of the raphe, the cuneiform nucleus, the ventral and dorsal nuclei of the lateral lemniscus, the medial nucleus of the solitary tract, the dorsal motor nucleus of the vagus, and the cuneate nucleus. Other brainstem regions such as the area postrema, the external division of the lateral reticular nucleus, the nucleus ambiguus, the nucleus intercalatus, the nucleus incertus, the pyramidal tract and the trapezoid body had the lowest density of immunoreactive fibers.

The distribution of galanin-like immunoreactive fibers and cell bodies has been studied in the cat brainstem. Perikarya containing galanin were only found, at a low density, in the nucleus of the brachium of the inferior colliculus and in the pericentral nucleus of the inferior colliculus. The highest density of immunoreactive fibers was found in the laminar spinal trigeminal nucleus and in the parvocellular division of the alaminar spinal trigeminal nucleus. A moderate density of immunoreactive fibers was observed in the periaqueductal gray, locus coeruleus, marginal nucleus of the brachium conjunctivum and below the facial nucleus, whereas a low density of such fibers was found in the nucleus of the brachium of the inferior colliculus, pericentral nucleus of the inferior colliculus, nucleus incertus, medial division of the dorsal nucleus of the raphe, accessory dorsal tegmental nucleus, Kölliker-Fuse nucleus, lateral tegmental field, postpyramidal nucleus of the raphe, pericentral division of the dorsal tegmental nucleus, infratrigeminal nucleus, medial nucleus of the solitary tract, spinal trigeminal tract, dorsal motor nucleus of the vagus, and in the lateral reticular nucleus. According to the distribution of galanin-like immunoreactive structures in the cat brainstem, our data suggest that the peptide could be involved in respiratory, cardiovascular, nociceptive and auditory mechanisms.

A haemorrhage was simulated and analysis of dynamic behaviour of renal resistance, renal nervous activity and peripheral resistances were processed, with the aim of studying the paradoxical behaviour of renal resistance as opposed to peripheral resistances and the increase of sympathetic activity in hypovolemic shock situations using both non-linear models of the renal blood flow and arterial pressure and body fluids. The following conclusions can be made after comparing the results obtained by simulation with data related to animal experimentation models: the model is useful for its use in the analysis of nervous activity, resistance and renal flow in hypovolemic shock situations in humans and the control structure it puts forward can explain the paradoxical behaviour of renal vascular resistance as opposed to the peripheral resistances and the increase in the renal nervous activity in the aforementioned circumstances.

Using an indirect immunoperoxidase technique, the cell bodies and fibers containing cholecystokinin octapeptide in the brainstem of the cat were located. A high density of immunoreactive perikarya was observed in the lateral tegmental field and retrorubral nucleus, whereas a moderate density was found in the nucleus incertus, periaqueductal gray and dorsal tegmental nucleus. The nuclei coeruleus, sagulum, interpeduncular, motor dorsal nucleus of the vagus and nucleus of the solitary tract had a low density of immunoreactive cell bodies. The densest network of immunoreactive fibers was observed in the interpeduncular nucleus. The nuclei coeruleus, sagulum, praepositus hypoglossi, cuneiform, dorsal and ventral nuclei of the lateral lemniscus, marginal nucleus of the brachium conjunctivum, dorsal motor nucleus of the vagus, lateral tegmental field, inferior colliculus, periaqueductal gray and nucleus of the solitary tract had a moderate density of immunoreactive fibers. Finally, scarce immunoreactive fibers were found in the nucleus of the brachium of the inferior colliculus, inferior central nucleus, nucleus incertus, retrorubral nucleus and dorsal tegmental nucleus.

INTRODUCTION The objective of this study is to describe current tendencies in the recording and interpretation of visual evoked potentials (VEP). In the introduction we describe the history of the three main classical schools and the modern methodology which combines them, so as to study the photopic and scotopic systems together and thus be better able to determine the origin of the underlying pathology. MATERIAL AND METHODS We describe recording techniques using flash and chequer-board and a strategy for study of the visual pathway. RESULTS The application of this technique is described for pathologies in which its findings are of particular interest: Silent multiple sclerosis, Parkinson, hepatic encephalopathy, dementia and psychiatric disorders in which certain neurotransmitters play a part; visual acuity; coma and brain death; cortical blindness. A separate section deals with paediatrics, in view of its special characteristics. We call for a return to the use of this technique with great future diagnostic potential.

A mathematical, non-lineal model for digital simulation of the neural control of blood renal flow (BRF) has been built, by using the system dynamic techniques. The control mechanisms considered have been the BRF regulation by means of a renal intrinsic system, and by means of an RNA-dependent system, being the latter a product of the peripheral sympathetic activity, of a tonic inhibitory system with a central origin, and of a system that inhibits this last one, which has an intrarenal origin. For the validation of the model, a spinal section has been simulated, and the data have been compared with the reported in the bibliography. The use of this model permits an approach to the study of different variables in physiological or pathological circumstances in man, especially of those involved in the neural regulation of the BFR, obviating the technical and ethical obstacles of experimental techniques and leading to the design of new animal trials.

The modifications of larynx resistance changing bronchial tone were studied in cats. Changes on bronchial tone were evoked by intravenous administration of Carbachol (10 micrograms/kg) as bronchoconstrictor, and by Fenoterol (10 micrograms/kg) and Isoprenaline (0.1 mg/kg) as bronchodilators. The effects of Carbachol administration after these drugs were also studied. Larynx resistance was measured by the subglottic pressure value using the in situ isolated glottis technique. Subglottic pressure increases after Carbachol administration (p less than 0.001) and decreases after Fenoterol (p less than 0.02) and Isoprenaline (p less than 0.01). When Carbachol was administered after the bronchodilators subglottic pressure values were similar to those observed in control situations. A high positive correlation between changes of subglottic pressure and total lung resistance (p less than 0.01) was also observed. These results could suggest that glottis contraction was reflexively modified by bronchial tone.

The distribution of calbindin D-28k-immunoreactive fibers and cell bodies in the cat diencephalon has been analyzed by using the avidin-biotin immunoperoxidase technique. The thalamus showed a higher density of immunoreactive cell bodies than the hypothalamus. A high density of both immunoreactive perikarya and fibers was observed in the nuclei pulvinar, geniculatum mediale and laterale, lateralis posterior and dorsalis, habenularis lateralis and medialis, posterior, subparafascicularis, submedius, centralis medialis, medialis dorsalis, ventralis postero-medialis and postero-lateralis, reticularis, centralis lateralis, rhomboidens, paracentralis, ventralis lateralis, anterior and medialis, reuniens, anterior ventralis and medialis, hypothalamus posterior, corpus mamillare, area hypothalamica dorsalis and in the hypothalami ventromedialis. Moreover, a high density of fibers containing calbindin and a moderate/low density of immunoreactive cell bodies was found in the nuclei periventricularis anterior, parataenialis, hypothalamus lateralis, mamillaris lateralis, filiformis, periventricularis hypothalami, hypothalamus anterior and in the suprachiasmaticus.

Primary peptidergic sensory neurons of the trigeminal ganglion that innervate the cerebral dura have been involved in the pathogenesis of headache, including the migraine. In addition, it is known that nociceptive central processes of the trigeminal neurons terminate in the caudal trigeminal nucleus. Moreover, the electrical stimulation of the trigeminal ganglion has been used as an experimental model in order to study the vascular headache, including the migraine.To study whether there is or not a decrease of the immunoreactivity for methionine enkephalin, somatostatin and neurotensin in the caudal trigeminal nucleus after electrical stimulation of the trigeminal ganglion.The trigeminal ganglia of Wistar albino rats of both sexes were electrically stimulated (frequency, 5 Hz; duration, 5 ms; intensity, 0,8 1.4 mA) and unilaterally for five minutes. Sections of the medulla oblongata containing the caudal trigeminal nucleus were obtained and processed for immunocytochemistry, in which specific antibodies were used against methionine enkephalin, neurotensin and somatostatin 28.In stimulated animals, we observed a decrease in the immunoreactivity for the three neuropeptides studied in the stimulated (ipsilateral) side, in comparison with the not stimulated side (contralateral). In control animals (not stimulated) the degree of the immunoreactivity was the same on both sides.1. The decrease of the immunoreactivity in the ipsilateral side (stimulated) suggests that methionine enkephalin, neurotensin and somatostatin 28 are released in the caudal trigeminal nucleus after electrical stimulation of the trigeminal ganglion; 2. Methionine enkephalin and somatostatin 28 could act in the caudal trigeminal nucleus as inhibitors (with antinociceptive action) of another released exciters neuropeptides (with nociceptive action); and 3. These data will allow in the future to try new therapeutic strategies (e.g., the inhibition of the receptors implicated.), in order to alleviate certain headaches.