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Biomedical subjects

A Palacios

Publications and source records attributed to A Palacios.

At least 55 records · Page 3Linked to original sources
PubMed1991

The palmitic acid binding properties of cytosolic proteins located in the villus and crypt zones of bovine intestinal mucosa.

The palmitic acid binding capacity of cytosolic proteins in three preparations obtained by differential scraping of bovine intestinal mucosa were compared. The data indicated that the palmitic acid binding activities depended on the position that the cells occupied along the crypt-villus axis, as shown from the level of alkaline phosphatase activity. Proteins with palmitate binding properties in the high- and low-molecular-weight cytosolic proteins in the villus zone bound 1.24 +/- 0.41 and 1.54 +/- 0.16 pmol palminate/micrograms protein respectively. The binding decreased to 0.50 +/- 0.25 and 1.10 +/- 0.23 pmol palmitate/micrograms for the proteins in the crypt zone. Ammonium sulphate fractionation and gel filtration chromatography indicated that the low-molecular-weight cytosolic proteins obtained from light mucosal scrapings contained the highest palmitate binding activity. These results suggest that the cytosolic proteins located in the villus zone may play a role in the absorption of fatty acids.

Alkaline Phosphatase↗
PubMed1991

Selective fimbria and thalamic lesions differentially impair forms of working memory in rats.

Several series of experiments were designed to compare the effects of selective lesions of the fimbria or of thalamic nuclei on three different tasks involving working memory in rats: object recognition, place recognition, and the radial arm maze test. The main effects of fimbria lesions were as follows: they produced deficits in the radial maze; object recognition was spared or even facilitated, whereas place recognition was impaired. Electrolytic lesions of either centromedian-parafascicularis (CM-Pf) or dorsomedialis (DM) nuclei produced highly significant deficits in the radial maze test but spared object and place recognition. Ibotenate lesions of the CM-Pf had no effect on any test, which means that the critical structure in the effects of the electrolytic lesions of the CM-Pf was the fasciculus retroflexus (FR). These data may contribute two main points to animal models of hippocampal and thalamic amnesia: (1) different forms of working memory in rats might have different neural bases and (2) the FR may be involved in learning and memory processes.

Animals↗
PubMed1991

Apathetic hyperthyroidism in middle age.

Apathetic hyperthyroidism was first described in the medical literature by Lahey in 1931. It is a form of hyperthyroidism found principally in the elderly population. In this disorder the usual hyperkinetic presentation of thyrotoxicosis is replaced by apathy and inactivity, often leading to an erroneous psychiatric diagnosis. Although there is a paucity of literature on apathetic hyperthyroidism, it has been described in the elderly and as an extremely rare complication of hyperthyroid disorder in children. It was described only rarely in middle age. The following case highlights the diagnostic and therapeutic dilemmas encountered in a middle-aged patient who presented with dementia and apathetic hyperthyroidism.

Antithyroid Agents↗
PubMed1991

How can we combat excess mortality in Harlem: a one day survey of substance abuse in adult general care.

Our hypothesis was that a one-day survey of all patients hospitalized on Adult General Care would demonstrate a need for expanded addiction services in a municipal teaching hospital in East Harlem. We interviewed 276 patients in Adult General Care on February 16, 1990 to assess whether they abused drugs or alcohol or were hospitalized for reasons related to substance use. Of the 276 patients interviewed, 18 percent used alcohol alone, 14 percent used drugs alone, 17 percent used both drugs and alcohol and 2 percent were hospitalized for reasons related to substance use. One hundred forty or 51 percent of all patients were admitted because of substance use and its sequelae or as a result of violence associated with the buying or selling of drugs. The percentage was highest on one medical floor where 89 percent of the patients were substance users and on medical floors in general where the average was 60 percent. Forty patients or 14 percent were known to be HIV seropositive. Given the high mortality in Harlem, the results of our one-day survey indicate a need for expanded addiction services.

Acquired Immunodeficiency Syndrome↗
PubMed1991

[Psychophysical study of the chromatic discrimination in pigeons after lesions of thalamic nuclei Rotundus (RT) and Geniculatus Lateralis ventralis (GLv)].

The discrimination threshold at 510 and 640 nm has been measured before and after the bilateral lesion with kaïnic acid of two main thalamic structures: the nucleus rotundus (Rt) and the nucleus geniculatus lateralis ventralis (GLv). When the lesion destroys the GLv and the lower part of the Rt, thresholds increase followed by a progressive recuperation. In contrast, when the Rt lesion is complete, and whether the GLv is touched or not, the threshold increase is both higher and does not come down to the pre-operatory levels even after 15 post-operatory sessions.

Animals↗
PubMed1990

Color mixing in the pigeon. A psychophysical determination in the longwave spectral range.

Pigeons were trained to discriminate between spectral lights and additive mixtures in the 580-640 nm range. Two behavioral procedures were used: (I) a simultaneous instrumental discrimination and (II) successive "autoshaping" discrimination. Pigeons were able to make color mixture matches within this spectral range with satisfactory precision. Matchings determined by the animal correspond well to those predicted on the basis of the spectral sensitivities of two (or even three) pigment-droplet combinations present in the pigeon retina.

Animals↗
PubMed1989

The metoclopramide test: a useful tool with the luteinizing hormone-releasing hormone test in distinguishing between constitutional delay of puberty and hypogonadotropic hypogonadism.

To evaluate the effectiveness of intravenous metoclopramide, alone or in combination with luteinizing hormone-releasing hormone (LH-RH), in distinguishing between constitutional delay of puberty and hypogonadotropic hypogonadism, 12 patients with constitutional delay of puberty and 10 patients with hypogonadotropic hypogonadism were studied. All patients received 10 mg/m2 of intravenous metoclopramide and 100 micrograms of intravenous LH-RH on separate days. The mean prolactin (PRL) response following metoclopramide was significantly higher in the constitutional delay of puberty group when compared with the hypogonadotropic hypogonadism patients (P less than 0.01 at 15, 30, 45, and 60 minutes); all patients with constitutional delay of puberty increased their PRL level to greater than or equal to 60 ng/ml, except one who had a peak PRL level of 38 ng/ml. While only 2 of the hypogonadotropic hypogonadism subjects reached a peak PRL concentration of greater than or equal to 60 ng/ml, 4 had peak PRL levels greater than 38 ng/ml. The mean LH and follicle-stimulating hormone (FSH) responses after LH-RH were significantly higher in the constitutional delay of puberty group (P less than 0.01 at 30, 45, and 60 minutes for LH and P less than 0.01 at 45 and 60 minutes for FSH). All constitutional delay of puberty subjects responded to both the metoclopramide and LH-RH tests, while patients with hypogonadotropic hypogonadism responded only to one or to neither of these tests. Therefore, while metoclopramide alone did not allow us to clearly distinguish constitutional delay of puberty from hypogonadotropic hypogonadism, the combined use of both of these stimuli permitted us to detect all subjects with constitutional delay of puberty.

Adolescent↗
PubMed1989

Fatty acid binding proteins in bovine intestinal mucosa.

Cytosol obtained from bovine intestinal mucosa, contains two protein fractions that bind sulfobromophthalein and are able to remove [1-14C] palmitic acid from microsomal membranes. The high molecular weight protein fraction (F1) increases the binding of sulfobromophthalein 2 and 8 times respectively after heating at 60 degrees C during 5 min or delipidation. These changes do not correlate with the rate of palmitic acid removal from microsomes. F1 native or delipidated is more efficient than the low molecular weight protein (F2) on the removal of [1-14C]palmitic acid from microsomes. Two protein fractions DE-I and DE-II obtained from F1 by DEAE-cellulose chromatography have palmitic acid- and sulfobromophthalein-binding capacities respectively.

Animals↗
PubMed1988

Thoracic ureter.

We report a case of a somewhat dilated ascending and descending ureteral segment penetrating into the thorax with moderate symptoms. The diagnosis was made by excretory urography. To our knowledge, our case represents the first such report in the literature.

Humans↗
PubMed1987

Effects of selective lesions of fimbria-fornix on learning set in the rat.

The effects of selective partial lesions of the Fimbria-Fornix (FiFx) on reversal and place learning sets were investigated in rats by using a T-maze and a semi-circular multiple discrimination apparatus. Lesions restricted to the Fimbria (Fi) produced a significant deficit in reversal and place learning set, whereas lesions to the Fornix (Fx) only disturbed the learning set based on a reversal procedure. Combined Fi + Fx lesions resulted in impairment in the retention of spatial discrimination tested in the two mazes. Ventral Hippocampal Commissure (vhc) had no significant effect on reversal learning set. These results confirm previous data that the hippocampal formation is involved in learning transfer, and suggest that the Fi and the Fx may play a role in learning set. Our data also confirm previous demonstrations of the ability of rats to rapidly acquire place learning set.

Animals↗
PubMed1984

A clinical syndrome of mild androgen insensitivity.

We studied four patients from three kindreds who had normal male body habitus and external genitalia except for short penile length and gynecomastia. Prostate size was small in all patients and spermatogenesis was decreased markedly in one and absent in three. Testicular biopsies in two patients revealed normal histology but evidence of spermatogenic arrest at the spermatocyte stage. Circulating levels of testosterone and LH were increased and the testosterone-dihydrotestosterone ratios were normal. Plasma estradiol was elevated in three of the four patients. Serum FSH levels were significantly elevated in only one patient. The response of LH and FSH to LHRH stimulation was normal in the two patients who were tested. Despite the normal male phenotype, the laboratory studies suggested the diagnosis of androgen insensitivity. This was confirmed in two patients by finding decreased dihydrotestosterone-binding capacity in genital skin fibroblasts. Two of the patients had normal levels of androgen receptor binding, suggesting that their defect represented a mild form of androgen insensitivity with normal receptor activity. These results demonstrated that mild forms of androgen insensitivity exist in which the only obvious clinical manifestations may be the presence of reduced penile length, gynecomastia, and/or infertility. The incidence of androgen insensitivity among men with these subtle phenotypic abnormalities, including infertility, remains to be determined.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
PubMed1983

Decreased secretion of cortisol and ACTH after oral clonidine administration in normal adults.

Clonidine, a selective noradrenergic receptor agonist, has been shown to affect various hormones acutely. It increases growth hormone levels in animals and in human adults and children. The effect of clonidine upon ACTH and cortisol levels is not as clear, and both stimulatory and inhibitory effects have been reported. We found a significant decrease in plasma cortisol decreased. No changes in FSH, LH, or prolactin were seen after oral clonidine. Our data are compatible with an inhibitory noradrenergic mechanism modulating ACTH and cortisol secretion in normal adults.

Adrenocorticotropic Hormone↗