PubMed Health⌕ Search

Biomedical subjects

S Pons

Publications and source records attributed to S Pons.

At least 19 recordsLinked to original sources
PubMed1992

[Coronary heart disease and lipoprotein (a): relationship with other lipid cardiovascular risk factors].

BACKGROUND: Lipoprotein (Lp) (a) is considered a risk factor for early coronary heart disease (CHD), and a discriminant cutoff of Lp(a) concentration has been suggested. METHODS: Serum Lp(a) concentrations have been determined by enzymoimmunoassay in 66 men with CHD and in 100 healthy control men. Serum cholesterol, serum triglycerides, high density lipoprotein (HDL)-cholesterol, and apoprotein (apo) A-I were also determined. RESULTS: Serum Lp(a) concentration was 21.7 +/- 16.9 mg/dl (mean +/- SD) in patients and 12.5 +/- 12.5 mg/dl in controls (p less than 0.001). Serum cholesterol was 5.63 +/- 1.22 mmol/l and 5.29 +/- 1.00 mmol/l (p less than 0.05) respectively; serum triglycerides were 1.99 +/- 1.23 mmol/l and 1.29 +/- 0.61 mmol/l (p less than 0.001) respectively; HDL-cholesterol was 0.97 +/- 0.27 mmol/l and 1.07 +/- 0.30 mmol/l (p less than 0.05) respectively; and apo A-I was 94 +/- 15 mg/dl and 144 +/- 41 mg/dl (p less than 0.001) respectively. Lp(a) concentrations were not correlated with other well-recognized cardiovascular risk lipidic factors, nor influenced by age either body mass index. Using 20 mg/dl as discriminant Lp(a) concentration between patients and controls, a ratio 2:1 in patients with respect to controls has been observed and exceeded some more when the threshold level was put on 30 mg/dl. A subset of normocholesterolemic and normotriglyceridemic patients (n = 17) and controls (n = 49) had serum Lp(a) concentration of 22.7 +/- 16.3 mg/dl and 9.1 +/- 8.2 mg/dl (p less than 0.001) respectively. CONCLUSIONS: Increased concentration of Lp(a) constitutes an independent risk factor for CHD. On the other hand, Lp(a) concentrations of 20 mg/dl or 30 mg/dl as risk threshold levels are well-defined.

Adult↗
PubMed1992

Estradiol promotes cell shape changes and glial fibrillary acidic protein redistribution in hypothalamic astrocytes in vitro: a neuronal-mediated effect.

We have previously shown that in hypothalamic mixed neuronal-glial cultures both astrocytic shape and distribution of glial fibrillary acidic protein (GFAP) are modified by estradiol. In the present study, we have investigated whether or not the presence of neurons is necessary for these hormonal effects. In mixed neuronal-glial hypothalamic cultures the proportion of process-bearing GFAP-immunoreactive cells was significantly increased after treatment for 30 min with 10(-12) M 17 beta estradiol. This effect was present for at least 1 day and was reverted by incubating the cells in estradiol-free medium. Estradiol incubation resulted in a progressive differentiation of GFAP-immunoreactive cells from a flattened epithelioid morphology to bipolar, radial, and stellate shapes. This effect was not observed in pure hypothalamic glial cultures. Furthermore, incubation of hypothalamic glial cells with medium conditioned by estradiol-treated mixed hypothalamic cultures did not affect the shape of GFAP-immunoreactive astrocytes. In contrast, addition of hypothalamic neurons, but not cerebellar neurons or fibroblasts, to established hypothalamic glial cultures affected the development of estradiol sensitivity in astrocytes. These results indicate that estradiol induction of shape changes in hypothalamic astrocytes is not only dependent on the presence of hypothalamic neurons, but that physical contact between astrocytes and neurons is necessary for the manifestation of the effect of this hormone.

Animals↗
PubMed1992

Volatile fatty acids, lactic acid, and pH in the stools of breast-fed and bottle-fed infants.

We measured fecal pH, volatile fatty acids (VFA), and lactic acid concentrations in 67 healthy infants ranging in age from 1 to 5 months. The babies were divided into five groups according to their diet: group 1: human milk, with subgroups of 1 month of age (n = 8), and 2-5 months (n = 12); group 2: formula milk, with subgroups of 1 month of age (n = 9) and 2-5 months (n = 10); group 3: cow's milk, one group of 2-5 months of age (n = 12); group 4: human milk supplemented with formula milk, 2-5 months of age (n = 8); and group 5: human milk supplemented with cow's milk, 2-5 months of age (n = 8). Fecal VFA concentration and pH of bottle-fed infants (groups 2 and 3) were significantly higher and lactic acid concentrations significantly lower than those of the breast-fed group. Groups 4 and 5 showed significantly higher pH and propionic acid concentration, and lower lactic acid concentration than Group 1 did. There were no significant differences in the data on pH, VFA, and lactic acid concentrations between the feces of formula and cow's milk groups. On the other hand, the addition of formula or cow's milk to the human milk was sufficient to alter the profile of VFA, the pH, and the lactic acid concentration of breast-fed infants stools. Low pH, low VFA, and high lactic acid concentrations make the colonic content of breast-fed babies an environment favorable for Bifidobacteria growth, and this is probably the main protective factor against gastrointestinal infections.

Acetates↗
PubMed1992

Basic fibroblast growth factor modulates insulin-like growth factor-I, its receptor, and its binding proteins in hypothalamic cell cultures.

Interactions between different growth factors may be important in the regulation of cell growth and differentiation in the nervous system. For instance, basic fibroblast growth factor (bFGF) regulates neuroblast division through a mechanism probably involving insulin-like growth factor-I (IGF-I). In this regard, we previously found that simultaneous addition of both factors produces an additive effect on survival and differentiation of hypothalamic neuronal and glial cells in culture. To further analyze these interactions, we explored the influence of bFGF on IGF-I, its membrane receptor, and its binding proteins in hypothalamic cells. We also tested the effects of IGF-I on its own receptor and binding proteins (IGFBPs) to determine the specificity of bFGF's actions. Treatment of neuronal and glial cultures with bFGF produced an increase in IGF-I receptors, without changing their affinity, together with an increase in the apparent M(r) of the receptor. On the other hand, IGF-I elicited a down-regulation of its own receptor in both neurons and glia, without modifying its affinity. Treatment with bFGF also produced a marked differential effect on the IGFBPs secreted by the cells. While IGFBP levels in neuronal cultures were greatly increased by bFGF, their production by glial cells was inhibited. On the other hand, IGF-I increased the amount of IGFBPs in both types of cells. Finally, addition of bFGF to the cultures elicited a dose-dependent increase in the release of IGF-I to the medium, but only a moderate increase in cellular IGF-I content, in both neurons and glia. We conclude that bFGF strongly modulates IGF-I, its receptors, and its binding proteins in the two major cell types of the hypothalamus. These findings reinforce the possibility that IGF-I and/or its receptors and binding proteins are involved in the trophic effects of bFGF on developing brain cells.

Animals↗
PubMed1992

Morphofunctional changes in gastrointestinal tract of rats due to cafeteria diet.

Female rats fed a cafeteria diet from birth developed obesity at 60 days of age and their stomach, small intestine and caecum were enlarged when compared with controls, i.e. these regions had greater food storage capacity. In spite of the enlargement, these regions had similar or reduced weight and linear density, which is seen as proof of reduced mechanical performances. Cafeteria diet produced increased glucose duodenal absorption in older animals unlike the typical reduction known in controls. Tryptophan absorption was maintained high in adulthood, compensating for the low structural nutritive properties of the cafeteria diet. The results are interpreted as an adaptation to the cafeteria diet effects and properties: the characteristic overeating of foodstuffs with greater energy density, lower mechanical requirements and lower structural nutritive value than pelleted chow.

Adaptation, Physiological↗
PubMed1991

Climbing fiber deafferentation reduces insulin-like growth factor I (IGF-I) content in cerebellum.

The presence of insulin-like growth factor I (IGF-I) and its mRNA in adult rat cerebellum has recently been documented. Previous immunocytochemical studies showed prominent IGF-I-like staining in fibers around Purkinje cell somas. To determine the origin of this IGF-I input to the Purkinje cell we destroyed the inferior olivary complex by either 3-acetylpiridine administration or electrolytical lesions. In both types of lesions we found a similar significant depletion of IGF-I levels in cerebellum (40-50% of controls). No changes were found in cerebellar IGF-I receptors. These results suggest that almost half of the IGF-I content in cerebellum is provided by climbing fiber afferents arising from the inferior olivary complex.

Animals↗
PubMed1991

Ontogeny of insulin-like growth factor I, its receptor, and its binding proteins in the rat hypothalamus.

A role for the insulin-like growth factors (IGFs) in brain growth and differentiation has recently been suggested. In previous studies on fetal hypothalamic cells we found a trophic influence of IGF-I on in vitro survival and differentiation of both neurons and glia. We have now investigated the expression of IGF-I, its receptor and its binding proteins in the rat hypothalamus to determine whether endogenous IGF-I might serve as a trophic factor during development of this brain area. Both IGF-I receptors and IGF-I binding proteins showed marked developmental stage-dependent variations. Thus, IGF-I receptors as measured by both binding and cross-linking techniques, were highest during fetal life and steadily decreased thereafter to reach low adult levels. Changes in receptor numbers rather than in its affinity constant accounted for the differences seen in binding activity during development. In addition, we found 3 different IGF-I binding proteins (IGFBPs) of apparent Mr of 24, 29 and 32 kDa respectively, whose levels also showed a specific developmental pattern. Highest levels of the 29 and 32 kDA IGFBPs were found in fetal and early postnatal life, whereas levels of the 24 kDa form were highest in young adults. Changes in the concentration of IGFBPs rather than in their affinities for IGF-I accounted for the different binding capacities found. Using a specific IGF-I radioimmunoassay we found that IGF-I-like immunoreactivity (IGF-I-li) levels had no direct correlation with developmental stage. IGF-I-li levels oscillated with no apparent trend throughout development of the hypothalamus.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Localization of insulin-like growth factor I (IGF-I)-like immunoreactivity in the developing and adult rat brain.

The cellular distribution of insulin-like growth factor I (IGF-I) immunoreactivity was examined in the rat brain from embryonic day 15 to maturity. IGF-I immunoreactivity was found in the perikarya of neurons distributed along the entire extension of the neuronal tube in all the embryonic ages studied (E15, E17, E19 and E21). In E21 animals, the majority of immunoreactive neurons was located in the olfactory bulb, cerebral cortex, hippocampus, striatum, diencephalon, mesencephalic colliculi, trigeminal nuclei, trigeminal ganglion and in motoneurons of the brainstem. In 10- and 20-day-old rats, in addition to the above areas, IGF-I immunoreactivity was also observed in capillary walls, ependymal cells, choroid plexus, glial cells and most fiber paths. In postnatal ages, immunoreactivity in neuronal somas was mainly restricted to the cell nuclei. However, IGF-I immunoreactivity in the neuronal cytoplasm was observed in 20-day-old rats treated with colchicine while fiber paths and neuronal cell nuclei were negative in these animals. In the telencephalon of 20-day-old rats injected with colchicine, the most intense immunoreactive neurons were observed in the olfactory bulb, cerebral cortex, tenia tecta, hippocampus, islands of Calleja, septal nuclei, striatum, endopyriform nucleus and amygdala. Most diencephalic nuclei, the substantia nigra, the mesencephalic colliculi, Purkinje cells in the cerebellar cortex and several nuclei in mesencephalon, pons and medulla oblongata were also immunoreactive. In adult rats injected with colchicine, IGF-I immunoreactivity was located in the same areas as in 20-day-old rats. The number of immunoreactive cells and the intensity of the staining was reduced in adult rats as compared to that found in young postnatal animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Effect of loperamide and bisacodyl on intestinal transit time, fecal weight and short chain fatty acid excretion in the rat.

We analyzed the effect of drugs that modify the colonic motility on rat intestinal transit time (ITT) (measured with radiopaque markers), fecal weight (FW) and fecal concentration of short chain fatty acids (FSCFA) (assayed by gas liquid chromatography), over a four-week period. Bisacodyl was used to accelerate and Loperamide to retard the intestinal transit in rats maintained on a conventional diet. The first and 3rd week were drug-free control periods. The mean values of these periods were: ITT = 28.9h +/- 1.9 FW: 9.2 +/- 1.2 g/24 h and FSCFA = 60.6 +/- 17.9 mmol/g. After loperamide administration, we observed an increase in the mean ITT as compared to the control period (40.4 +/- 8.0h) and decrease in FW (4.8 +/- 3.6 g/24h) and in FSCFA = 32.2 +/- 5.6 mmol/g). After bisacodyl administration, we found a shorter ITT in relation to controls (24.8 +/- 2.5h), and increases in FW (27.5 +/- 3.6g/24h) and in FSCFA (108.2 +/- 39.9 mmol/g). There was a negative correlation between ITT and FW (R = 0.67 p less than 0.01) and a positive correlation between total SCFA concentration and FW (R = 0.71 p less than 0.01). The concentration of acetic, propionic and butyric acids increased with progressive increments in fecal weight, whereas concentrations of isovaleric and caproic acids decreased. The results of this study show that the FW and the FSCFA may be influenced by modifications in the intestinal transit time.

Animals↗
PubMed1990

A new precise microcomputer based rotometer.

The rotometer described here consists of a data acquisition system made of several reed relays which are activated by a small moving magnet when the animal performs rotations. The apparatus has an angular discrimination which is dependent on the number of reed relays used. A simple interface is used to normalize the pulses produced when the reed relay contacts are closed. This normalized output closes key contacts in the keyboard of a microcomputer resulting in ASCII strings. A simple BASIC program is used for computation of various turn fractions. The program also calculates the total number of movements over time, allowing the assessment of activity vs. time.

Amphetamines↗
PubMed1989

A prospective study of atrial fibrillation and stroke.

In a prospective study of 72 patients with stroke and atrial fibrillation, we classified strokes as cardioembolic or noncardioembolic based on arterial assessment using Doppler sonography and angiography. We analyzed and cross-tabulated 18 clinical characteristics and found four to be significantly associated with a cardioembolic mechanism: stroke with onset during activity and peak deficit at onset (p less than 0.008), previous infarct in a different vascular territory (p less than 0.01), previous transient ischemic attack in a different vascular territory (p less than 0.01), and transient ischemic attack lasting greater than 1 hour (p less than 0.02). Starting with these four characteristics, we used a step-down procedure to select variables for a logistic regression model. Only previous infarct in a different vascular territory (odds ratio = 7.38) and transient ischemic attack lasting greater than 1 hour (odds ratio = 7.89) were selected by the model. Using M-mode and two-dimensional echocardiography, we compared left atrial size in 46 patients with that in 78 controls who had atrial fibrillation without stroke. Left atrial size in patients and controls with mitral valvulopathy was significantly larger than that in patients and controls without mitral valve disease. There was, however, no difference in left atrial size between patients with nonvalvular atrial fibrillation and cardioembolic stroke and controls or patients with nonvalvular atrial fibrillation and noncardioembolic stroke. We concluded that some clinical characteristics are closely related to cardioembolic stroke and that left atrial enlargement reflects underlying cardiopathy rather than atrial emboli-forming capability.

Aged↗
PubMed1979

[Bullosis diabeticorum].

Three cases of Bullosis Diabeticorum, entity described by Rocca and Pereyra, are reported by the authors. The review of the published literature after the original article shows the importance of recognizing these symptoms for the diagnosis of an occult diabetes. The most outstanding features of the studied cases were: a) the bullosis traumatica present in the 3 observations; b) the finding of an unknown diabetes in two of the three patients; c) the association with stellate pseudoscars. The histopathologic findings were similar in all three patients.

Adult↗
PubMed1977

[Nevus lipomatosus cutaneous superficialis].

Two cases of naevus lipomatosus superficialis (Hoffmann and Zurhelle) are described by the authors. The main clinical characteristics and histological peculiarities are reviewed. Both cases were disseminated and had typical localisation (pelvic area). The histological examination showed ectopic adipocytes in the dermis. The authors mare a reference to the different hypotheses on the pathogenesis of these lesions.

Adolescent↗
PubMed1977

[Pemphigus with eosinophilic spongiosis].

A bibliographic review of a new subject-pemphigus with eosinophilic spongiosis accomplished: Three clinical courses are recognized: a) pemphigus in its initial phase, b) pemphigus markedly seborrheic, which presents during its evolution, some morphologic anomalies, c) pemphigus that appear like an authentic Duhring in its initial phase and during part of its evolution. On studying the histopathology three aspects are observed; 1) pure eosinophilic spongiosis with two modalites: diffuse or vesiculate; 2) mixed eosinophilic spongiosis and, 3) alternate eosinophilic spongiosis. The review report the study of this new observation and discusses the nosological situation as well as its pausible causation.

Adult↗
PubMed1977

[Epidemica of hand-foot and mouth disease].

After describing the affections caused by the virus Coxsackie, the characteristics of disease in mouth-hands-feet are looked over reporting the principal epidemic outbreak as well as the isolated forms of exhibition. The illness can be shown in a complete, incomplete or moderate way. This outbreak occurred in Mendoza (Argentina) in 1975-1976: 25 school aged children were controlled and no other relatives of different ages fell ill. No predisposition for either sex. They didn't come from the same school. A sudden eclosion and without general display. In some of them the buccal were absent. All of them had palm and sole lesions and only four of them had buttock lesions. Everybody recovered after a short eruptive period and without any complications.

Argentina↗