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Biomedical subjects

C Alvarez

Publications and source records attributed to C Alvarez.

At least 235 records · Page 13Linked to original sources
PubMed1987

Postnatal sequential development of dopaminergic and enkephalinergic perineuronal formations in the lateral septal nucleus of the rat correlated with local neuronal maturation.

Tyrosine-hydroxylase (TH-IR) and methionine-enkephalin like immunoreactivity (MetE-IR) were analyzed in the lateral septal nucleus (LSN) of the rat from birth (PO) to adulthood. TH-IR labeled specifically the dopaminergic (DA) pericellular arrangements of the LSN, as checked by negative dopamine-beta-hydroxylase and phenylethanolamine-N-methyl transferase-IR. TH-IR and Met-IR processes were present at birth in the medial LSN and extended lateralwards and caudalwards from P0 to P6 to constitute two main DA terminal fields (medial and lateral) surrounding a MetE one. Within these fields, the development of perineuronal baskets followed a similar medial to lateral sequence: DA axons first surrounded a few neuronal cell bodies at P3 in the medial part of the intermediate LSN; at P6, Met-IR axons encircled more laterally located perikarya, and only at P9, some neurons located along the ventricle in the lateral DA field became surrounded. The initial aspect of TH-IR baskets consisting of few axons surrounding the cell body rapidly evolved in a positive network encapsulating the perikaryon and long segments of the proximal dendrites, whereas MetE-IR varicosities remained restricted around the perikaryon and the initial dendritic segments. Ultrastructural study at P14 revealed numerous TH-IR and MetE-IR axosomatic and axodendritic profiles. TH-IR axosomatic varicosities exhibited asymmetrical synapses, whereas MetE-IR ones displayed rare symmetrical contacts. The medio-lateral gradient of development of the perineuronal baskets was parallel to the postnatal neuronal development of the LSN as evaluated by cytological criteria: neuronal density, cell size and Nissl staining. Therefore, the formation of DA and MetE perineuronal arrangements in the LSN does not seem to be subordinate to the nature of the neurotransmitter they contain but related to the level of differentiation of their target neurons. A similar sequential set-up in the development of afferences paralleling the neuronal differentiation is discussed.

Animals↗
PubMed1987

Biochemical and radioautographic evidence for dopaminergic afferents of the locus coeruleus originating in the ventral tegmental area.

The dopamine (DA) content of the locus coeruleus (LC) and the uptake of tritiated DA in the presence of desmethylimipramine into fresh vibratome sections of the LC-area were determined in control rats and in rats whose ventral tegmental area (VTA) had been destroyed by local application of 6-hydroxydopamine (6-OHDA). Destruction of the VTA reduced the DA content and the number of dopaminergic fibers visualized by radioautography in the LC area. This indicates that the DA containing afferents of the LC originate, at least partly, in the VTA.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1987

Steatorrhea in patients with intrahepatic cholestasis of pregnancy.

A prospective study was undertaken to evaluate fat malabsorption during intrahepatic cholestasis of pregnancy (ICP), a disease characterized by a mild cholestasis of short duration appearing in otherwise healthy young women. An abnormal fecal fat excretion (mean 15.8 g/24 h, range 6-31 g/24 h) was demonstrated in 10 of 12 patients with the icteric form of ICP and in 2 of 11 patients with pruritus gravidarum. The increased fecal fat excretion was generally asymptomatic, could be detected as early as 3 wk after the clinical onset of ICP, remained stable during the affected pregnancies, and returned to normal from 3 to 9 wk after delivery. Steatorrhea correlated with the severity of ICP, estimated by serum levels of bilirubin, total bile salts, and glutamic pyruvic transaminase. A significant fall in the maternal weight/height index was detected after the onset of ICP, being more intense in patients with steatorrhea than in those without it (to 92.6% +/- 3.0% of initial values versus 96.7% +/- 2.8%, respectively; p less than 0.05). A high risk of premature deliveries and fetal distress was demonstrated in these patients, also correlating with the severity of ICP. No direct relationship could be established between steatorrhea or maternal nutritional impairment and fetal prognosis.

Adolescent↗
PubMed1986

Major dopamine innervation of the cortical motor areas in the cynomolgus monkey. A radioautographic study with comparative assessment of serotonergic afferents.

Dopamine (DA) and serotonin (5-HT) innervations were revealed by radioautography in primary motor, premotor and supplementary motor (SMA) cortex in Cynomolgus monkeys, using uptake of tritiated amines in vibratome sections under specific conditions that were previously established. DA and 5-HT axons were distributed throughout all cortical layers. A denser DA innervation was found in layers I, III and to a lesser extent layer V with a striking cluster-like arrangement in layer III, particularly in the SMA. 5-HT axons appeared less numerous; their lower density in comparison with DA axons was especially apparent in layer III, particularly in the premotor and motor areas. A DA-5-HT complementarity was thus suggested in this layer. These results suggest that in addition to the motor control exerted through the nigrostriatal pathway, the cortical DA projections could directly modulate the neuronal activity in motor areas. This could be of major importance in the pathophysiology of motor disorders such as Parkinson's disease.

Animals↗
PubMed1986

Lipids, lipoproteins, and apoproteins in serum during infection.

We studied the alterations in the concentrations of total cholesterol, high-density lipoprotein cholesterol, triglycerides, and apoproteins A and B in serum of 54 patients hospitalized for various reasons, who developed sepsis during their stay. Forty of these patients required intensive care, 14 did not. Another group of patients with the same underlying pathological conditions was used as a control. We found the following: Sepsis causes the concentrations of total cholesterol, high-density lipoprotein cholesterol, and apoproteins A and B in serum to decrease, whereas triglycerides increase. However, these changes are not related to the infectious agent, the underlying illness, or the clinical situation of the patients. The return of serum lipids to more normal concentrations parallels the recovery from sepsis. The positive correlation between the drastically decreased concentrations of high-density lipoprotein cholesterol and the severe hypoalbuminemia in these patients suggests a common pathway for these two abnormalities.

Adolescent↗
PubMed1985

Catecholaminergic innervation of the septal area in man: immunocytochemical study using TH and DBH antibodies.

The catecholaminergic innervation of the human septal area and closely related structures has been visualized by using tyrosine hydroxylase (TH) and dopamine-beta-hydroxylase (DBH) as immunocytochemical markers. TH-like immunoreactivity with no corresponding DBH labelling was considered to be indicative of dopaminergic fibers. Catecholaminergic innervation offered the following similarities to that of rodents: moderate innervation in the medial septal division, with predominant DBH immunolabelling; dense dopaminergic innervation in the lateral septal nuclei, organized in a laminar pattern; presence of dopaminergic pericellular arrangements in the dorsal septum and bed n. of the stria terminalis; clustering of dopaminergic terminals in n. accumbens associated with a medioventral zone of DBH-like immunoreactive fibers; close overlap between dopaminergic fields and acetylcholinesterase-reactive zones in both the lateral septum and the n. of the stria terminalis. Differences with the catecholaminergic septal innervation of rodents consisted of general caudal extension of the dopaminergic fields, possibly accounted for by the vertical stretching and caudal displacement of the septal nuclei in man; complementary lateromedial topography of dopaminergic and DBH-immunoreactive inputs in the n. of the stria terminalis as opposed to their dorsoventral organization in rodents; presence of TH-immunolabelled cell group in the anterior olfactory nucleus and parolfactory cortex, which seems specific for primates. Precise topographical mapping of the catecholaminergic structures in this central region of the limbic forebrain seems to be a prerequisite for accurate tissue sampling in the biochemical investigations of pathological cases and should help in the interpretation of aminergic dysfunction in a variety of human diseases.

Acetylcholinesterase↗
PubMed1985

New dopaminergic terminal fields in the motor, visual (area 18b) and retrosplenial cortex in the young and adult rat. Immunocytochemical and catecholamine histochemical analyses.

New dopaminergic terminal fields have been visualized in the rat cerebral neocortex, using two morphological methods based on distinct properties of the dopaminergic system: presence of the first synthetic enzyme, tyrosine hydroxylase, and high-affinity uptake of amines. Tyrosine hydroxylase was used as an immunocytochemical marker after destruction of the cortical noradrenergic system, induced either neonatally by 6-hydroxydopamine or later on by DSP4, and controlled by the absence of dopamine beta-hydroxylase immunoreactivity. The uptake and storage of exogenous amines in tissue sections, in the presence of selective high-affinity transport inhibitors, enabled the specific visualization of the dopaminergic system with fluorescence histochemistry. A dopaminergic innervation of low density was observed along a dorsal sagittal strip which extended from the genu of corpus callosum until about 2 mm behind the splenium and encompassed several distinct cytoarchitectonic areas in the sensorimotor and visual cortex (medial and lateral agranular field, area 18b), as well as in discrete zones of the retrosplenial granular 29c,b, and agranular 29d areas. The distribution of these dopaminergic fields suggested a columnar organization. Several characteristics of the dopaminergic innervation were similar to that of the superficial anterior cingulate cortex (area 24): the laminar distribution to the superficial I-III layers, the secondarily developed varicose aspect in catecholamine fluorescence histochemistry and the delayed postnatal ingrowth in contrast with the early prenatal dopaminergic input to the prefrontal cortex. These similarities suggested that the subpopulation of dopaminergic neurons which provides projections to the anterior cingulate cortex could also contribute to the motor and visual cortex and thus play a role in sensorimotor integration. The predictive value of these results in the ascent of the phylogenetic scale are further considered.

Aging↗
PubMed1985

Morphological evidence for a dopaminergic terminal field in the hippocampal formation of young and adult rat.

We have visualized the dopaminergic innervation of the hippocampal formation of the rat using two morphological methods: (1) tyrosine hydroxylase immunocytochemistry on noradrenaline-depleted animals and (2) fluorescence histochemistry after the uptake and storage of dopamine on hippocampal slices in vitro. The noradrenergic hippocampal terminal fields were destroyed by neonatal neurotoxin pretreatment and the validity of the lesion checked by the absence of dopamine beta-hydroxylase immunoreactivity. As observed on early postnatal ages, dopaminergic axons reached the hippocampal formation through the fimbria and the alveus, but also through the supracallosal bundle and the ventral amygdaloid area-entorhinal cortex. The temporal (ventral and caudal) part of the hippocampal formation received the bulk of the dopaminergic innervation whereas no fibers were observed in the septal pole. Very few positive axons were visualized in the hilus of the gyrus dentatus and CA3 field, only near the temporal pole. CA1 field (stratum oriens) was innervated throughout its ventral part. The most innervated area was the ventral part--especially the deep layers--of the subiculum, in particular the prosubiculum. The dorsal part of the subiculum displayed some positive axons, although to a lesser extent. The pre- and parasubiculum contained a few positive axons. In addition, some immunoreactive axons were observed in the anterior hippocampal continuation and the indusium griseum. The ventral junction prosubiculum-CA1 field appears to be the main target area for the hippocampal dopaminergic innervation. It is interesting that the same areas are characterized by their projections to the nucleus accumbens which receives dopaminergic afferents. Thus, the hippocampostriatal projections, that represent a link between the limbic and central motor mechanisms, could be under dopaminergic influence.

Age Factors↗
PubMed1985

Influence of hormones and undernutrition on brain development in newborn rats.

High L-thyroxine (T4) and cortisol doses given to rats during the first 8 days of life and on the first day only respectively, produce decrease of body and brain weight and perturbances to brain energy substrates, i.e. glucose and ketone bodies. The same alterations are found in the undernourished rats from the prenatal period. The pituitary GH and TSH is decreased in the T4- and cortisol-injected animals. The plasma ACTH is decreased in the treated cortisol animals at 8, 12 and 22 days of life. The pituitary TSH content is reduced with respect to controls in the undernourished animals from 14 to 70 days of life. From the exposed experiments we suggest an alteration in the hypothalamic-pituitary complex in T4- and cortisol-treated rats, and describe the similarities between the three experimental models.

Aging↗
PubMed1985

[Digestive Kaposi's sarcoma in patients with kidney transplantation--report of 2 cases].

Malignant tumors occur with greater frequency in patients with kidney transplants. Kaposi's sarcoma (KS), a rare vascular neoformation, represents approximately 3% of them. Its uncertain etiology appears to respond to: a chronic antigen stimulation by the transplanted tissue, to a depression of immune responsiveness, to the direct oncogenic action of the immunosuppressive agents, to the activation of oncogenic viruses or to a genetic predisposition of other possible factors. The clinical evolution is presented in two immunosuppressed kidney transplant patients with this pathology in the digestive tract. One had remission of the lesion following the suspension of the immunosuppressive agent. The relationship of this tumor with acquired immunodeficiency syndrome which occurred primarily (75%) in homosexuals shows a mortality rate of 30% due to KS. The first case showed signs of digestive hemorrhage and the typical nodule of KS was found in the esophagus on endoscopy. She also suffered a severe mixed infection due to Streptococcus faecalis and Cryptococcus neoformans with neurological complications and a new endoscopy 4 months after suspension of azathioprine showed the disappearance of the esophageal as well as the skin lesions. In the second patient, the suspicion of the digestive tract involvement could only be proved at autopsy. We insist on the importance of immunosuppression as a predisposing factor for the appearance of KS and infections in transplanted patients. It should also be remembered in cases with mucocutaneous lesions, that any digestive hemorrhage must primarily be attributed to KS and that the suspension of the immunosuppressive therapy constitutes the most effective treatment for the tumor.

Adult↗
PubMed1984

[Hodgkin's disease and the liver. Study of 50 biopsies].

A study of 50 liver biopsies (LB) is presented from a series of 45 patients with Hodgkin's disease as diagnosed by node biopsy in 40, by laparoscopic liver biopsy (LLB) or surgery in 5, with a simultaneous positive bone marrow study in one case. A total of 34 LLB and 16 blind liver biopsies were carried out For diagnosis of the disease the LB was positive in 2/7 or 28.5%. In order to establish the clinical status as a pre-treatment staging procedure in 30 cases, the biopsy was useful in 10% of the cases; whereas during the evolution of the disease in order to establish restaging in 13 patients, positivity was observed in 1 case (7.6%). In 7/34 with laparoscopic changes of the hepatic surface, invasion was later determined by LLB, surgery or autopsy in 71%, whereas with a normal surface infiltration was only established in 18.5% In 12 patients with liver invasion as demonstrated by LLB, laparotomy or autopsy, alkaline phosphatase was increased in 91.6%. We consider that the elevated number of false negatives (58.3%) is due fundamentally to the single biopsy technique performed some years ago with the Vim-Silverman needle instead of the procedure in use at present o repeated biopsies in both lobes when possible. Our experience of 50 LB in these 45 patients has been most useful in arriving at a diagnosis in 2, determining a change in stage on 3 occasions, demonstrating peritoneal and spleen involvement in 2 cases in addition to revealing other hepatic alterations.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1984

Reference intervals for serum lipids, lipoproteins, and apoproteins in the elderly.

We measured total cholesterol, high-density-lipoprotein cholesterol, low-density-lipoprotein cholesterol, triglycerides, apoprotein A, and apoprotein B in serum. The subjects were a volunteer group of 145 white people (50 men and 95 women) ranging in age between 65 and 95 years, who were not receiving medical treatment and had no disease that could influence lipid metabolism. Before further categorization, we saw no significant sex-related difference in any of these lipid constituents. The mean age of the group was about 80 years, and we compared results for those older and younger. For the women, the only significant difference was a decrease in low-density-lipoprotein cholesterol for those older than 80 years. In men over 80 there was a significant decrease in triglycerides and in apoprotein B and an increase in high-density-lipoprotein cholesterol. The only sex-related difference for persons under and over 80 was in values for high-density-lipoprotein cholesterol, which were higher for men over 80, whereas triglycerides were higher for women over 80.

Aged↗
PubMed1983

[Pathology of catecholaminergic innervation of the cerebral cortex in Alzheimer's dementia].

Changes in cerebral catecholaminergic pathways in Alzheimer type dementia would appear to involve both the noradrenergic and the dopaminergic system in their sub-cortical and cortical distribution, but the essential information currently available involves the noradrenergic innervation of the cerebral cortex. Involvement of this system was first detected by the authors using fluorescence histochemistry on biopsy specimens. In addition to the notable decrease in noradrenergic axons, three types of changes were seen: irregular axonal swelling with neurotransmitter diffusion phenomena, appearances of axonal interruption and, specific to the three cases of pre-senile form of Alzheimer's disease which were studied, the presence of large spherical or fusiform dilatations on the axonal endings, close to senile plaques. Thus histochemical study indicates the possibility of complex involvement, not only of synthesis of the neurotransmitter, but probably also of other properties of the noradrenergic axons: axonal flow, membrane permeability and hence, possibly liberation, uptake and storage of the mediator. These histochemical findings have been confirmed by other teams, who have demonstrated a neuronal loss of 20 to 80% in the locus coeruleus, a nucleus providing the cortical noradrenergic bundle. In addition, biochemical estimations have revealed either a severe reduction of the order of 90% in endogenous noradrenaline (3 personal cases), or a fall of 20 to 45% (cases from the literature), in relation with the method of biopsy or autopsy specimen and the form of pre-senile or senile dementia.(ABSTRACT TRUNCATED AT 250 WORDS)

Alzheimer Disease↗