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J M Torres

Publications and source records attributed to J M Torres.

At least 55 records · Page 3Linked to original sources
PubMed1994

Calbindin D-28k immunoreactivity in the rat cerebellar cortex: age-related changes.

The present study was designed to analyze age-dependent changes in the expression of calbindin D-28k immunoreactivity in the cerebellar cortex of male Wistar rats aged 3 months (young), 12 months (adult) and 24 months (old). Calbindin D-28k immunoreactivity was localized primarily in the cytoplasm of Purkinje neurons and in the basal portion of their dendritic processes entering in the molecular layer. The expression of calbindin D-28k immunoreactivity was highest in Purkinje neurons of adult rats and lowest in Purkinje neurons of old rats. Moreover, the number of Purkinje neurons displaying calbindin D-28k immunoreactivity was decreased in aged rats. These results demonstrate the occurrence of age-related-changes in the expression of immunoreactivity of the Ca2+ binding protein calbindin D-28k in the rat cerebellar cortex. The possibility that impairment in the expression of Ca2+ binding proteins may be involved in changes of intracellular Ca2+ homeostasis reported in aging and in some neuro-degenerative disorders is discussed.

Aging↗
PubMed1994

Endocytosis of three serum proteins of a multigene family and of arachidonic acid in human lectin-stimulated T lymphocytes.

Alpha-fetoprotein (AFP), serum albumin (SA), and vitamin D binding protein (DBP) are members of a multigene family of proteins showing high structural homology. AFP and SA exhibit a reciprocal relation during development and carry mostly fatty acids, while DBP carries vitamin D and its metabolites in the plasma. Covalent conjugates of these proteins with horseradish peroxidase (HRP) were used to follow by cytochemistry, at the electron microscope level, the protein uptake and intracellular pathways in peripheral blood human lymphocytes stimulated to blast formation by phytohemagglutinin (PHA). Transferrin (Tf), an iron-binding plasma protein, was used as a control. Combined with the results of competition and saturability experiments reported elsewhere, the ultrastructural observations are in favour of a specific endocytosis of the four proteins through cell surface receptors. Tf and AFP enter the cells via small vesicles and endosomes and move to multivesicular bodies (MVBs) and tubular vesicular elements located in the Golgi-centrosphere region to be finally recycled back into the medium. A noncovalent conjugate of AFP-HRP with 3H arachidonic acid [3H-(20:4)] is strongly internalized at 37 degrees C in PHA-stimulated lymphocytes; the autoradiographic labelling, localized in cellular membranes and mostly in lipid droplets, was only occasionally associated with organelles where the presence of AFP-HRP was cytochemically detected. SA, which competes with AFP for a common binding site on the surface of activated T cells, is endocytosed through small vesicles, endosomes, and MVBs before being released in a degraded form from the cells, in agreement with the localization of SA-HRP in lysosome-like organelles. DBP-HRP is poorly internalized through noncoated vesicles, endosomes, and MVBs and is finally routed to lysosomes. The physiological role of AFP and SA would be to mediate the transfer of fatty acids into cells, while that of DBP would be to facilitate the intracellular delivery of vitamin D.

Arachidonic Acid↗
PubMed1994

Carrier-protein-mediated enhancement of fatty-acid binding and internalization in human T-lymphocytes.

Albumin and alpha-fetoprotein (AFP) are members of a multigene family which also includes vitamin-D-binding protein. Previous work in our laboratory has provided experimental support for the suggestion that the entry of unsaturated fatty acids into growing, normal and neoplastic cells may be regulated by AFP. In the actual study we have examined the role of human serum albumin (HSA) as a carrier protein, when compared to AFP, on the uptake (binding and internalization) of fatty acids by resting and PHA-activated human lymphocytes. Radioiodinated human HSA and tritiated oleic and arachidonic acids were used under different experimental conditions to follow the binding of the protein and fatty acids (FA) to cells. Time-course uptake at 4 degrees C of HSA and of oleic and arachidonic acids bound to HSA (FA/HSA molar ratio = 1) by either resting or activated T-lymphocytes exhibited a steady state of binding. The amount of FA bound was much greater than the corresponding amount of HSA, suggesting that T-lymphocytes bear distinct binding sites for albumin and fatty acids. A saturable process of FA binding was observed at constant unbound FA concentration in the incubation medium when the HSA-to-FA molar ratio was fixed at 1 and the concentrations of both HSA and FA were increased simultaneously. This saturable component of binding reflects an intrinsic regulatory effect of HSA, probably operating throughout the interaction of the protein with specific cell receptors. At varying unbound FA concentrations, binding curves showed two distinct components: a non-linear portion which could indicate the presence of a saturable process operating at low concentrations of unbound, free FA, followed by a second part which increased linearly with the concentration of unbound FA. The amount of FA bound at 4 degrees C and bound and internalized at 37 degrees C by both types of cell was considerably higher in the presence than in the absence of carrier proteins. On the contrary, carrier proteins were without effect on the distribution pattern of internalized oleic or arachidonic acid. Taken together, these observations suggest that: (i) the binding and entry of FA into cells is enhanced by the two carrier-proteins at low concentrations of free, unbound fatty acids in the vicinity of the cell surface, and (ii) fatty-acid uptake seems regulated by a dual-receptor mechanism involving HSA and/or AFP receptors as well as plasma-membrane FA-binding proteins.

Arachidonic Acid↗
PubMed1994

[Laparoscopic hysterectomy. Initial experience].

The results of the first twelve cases of Laparoscopic Assisted Vaginal Hysterectomy, are presented. The indications for hysterectomy were myomatosis, suspicion of adenomyosis and endometriosis. The surgical technique is described in detail in which a combination of bipolar Kleppinger forceps and reusable scissors were employed. There were two intraoperative accidents. One subcutaneous emphysema of the left half of the abdominal wall, thorax, neck, face and upper limb. The second case was a damage to a branch of the left epigastric artery. The average time was 4 hours 31 minutes which includes 9 patients to which another surgical procedure was practiced. There was no significant bleeding in any of the patients. The postoperative complications were 1 hyponatremia that needed the use of an Intensive Care Unit and the other was periumbilical hematoma of 3 cm. of diameter. The patient was discharged on the one to three postoperative day with an average of two days. The average hospital fee was 35% higher than an abdominal hysterectomy. All the surgery were videotaped and later viewed by the patients. It was concluded that the laparoscopic assistance that is offered to the vaginal hysterectomy is particularly advantageous for hysterectomy especially in the cases where absence of genital prolapse, when uni or bilateral Adnexectomy is required, previous past history of abdomino-pelvic surgery, endometriosis and adhesions. This procedure should be included in the armamentarium of the Gynecological Surgeons but only after and appropriate training.

Adenoma↗
PubMed1993

Current notions of genotype and phenotype vis-à-vis new experimental evidence in molecular biology. A methodological study instigated by the peculiar nature of the HIV-1.

The strict separation of the biological roles of information and function as if they were two mutually exclusive aspects and the absolute identification of the former with nucleic acids and the latter with coded protein machinery has biased biological thinking to the extent that these notions act as very principles in contemporary biology. However, recent discoveries within the realm of RNA-viruses show the traditional application of such notions to be severely limited in conceptual terms.

DNA, Viral↗
PubMed1992

Membrane proteins from lymphoblastoid cells showing cross-affinity for alpha-fetoprotein and albumin. Isolation and characterization.

AFP or SA immobilized on nitrocellulose membranes (AFP-NC or SA-NC) were used as affinity matrices to purify cell membrane proteins with affinity for AFP (AFP-BP) and for SA (SA-BP) from membrane-enriched extracts of Raji cells (a B-lymphoma cell line), as well as for normal resting and activated peripheral blood lymphocytes (PBMC). SDS-PAGE and ligand blotting assays showed that AFP-BP and SA-BP isolated from Raji cells are probably identical molecules. They consisted of two sets of polypeptides of 31 kDa and 18 kDa. The glycoprotein nature of isolated 31 kDa and 18 kDa peptides was suggested by positive staining with Schiff's reagent, and amino-acid analysis revealed similar amino-acid composition for the two glycoproteins. In human PHA-activated PBMC, only the 18 kDa polypeptide was identified and isolated as AFP-BP or SA-BP. As in Raji cells, this 18 kDa polypeptide, isolated by affinity for AFP or for SA, appeared to be the same molecule. Contrary to Raji cells and activated PBMC, no proteins with an affinity for AFP or for SA were identified or isolated in resting PBMC. These observations strongly suggest that the isolated 31 kDa and 18 kDa glycoproteins are probably AFP receptors previously demonstrated in several neoplastic and normal cells undergoing growth and/or differentiation; indeed, they were identical to albumin-binding proteins described by others.

Amino Acids↗
PubMed1992

Receptor-mediated uptake and processing of vitamin D-binding protein in human B-lymphoid cells.

Vitamin D-binding protein (DBP), a member of a multigene family including alpha-fetoprotein (AFP) and albumin, is a serum glycoprotein that reversibly binds and transports vitamin D and its metabolites to target cells. In this work, we demonstrate that normal and malignant human B-lymphocytes specifically bind and internalize DBP. Radioiodinated DBP (125I-DBP) was used to follow the uptake of the protein by Raji cells, a human pre-B-lymphoma cell line. Time course studies of DBP uptake by these cells exhibited a saturable profile at both 4 and 37 degrees C. The binding saturation curve obtained by incubating Raji cells at 4 degrees C with different concentrations (1.5 nM to 1.5 microM) of 125I-DBP showed two saturation plateaus; Scatchard analysis showed the presence of two groups of receptor sites with a Kd1 of 2.04 x 10(-7) M (n1 = 42,161 +/- 4,336 sites/cell) and a Kd2 of 1.01 x 10(-6) M (n2 = 198,000 +/- 48,000 sites/cell). After incubation of Raji cells at 37 degrees C with both fluorescein isothiocyanate (FITC) and horseradish peroxidase conjugates, DBP was internalized and could be localized in the cytoplasm. DBP-horseradish peroxidase conjugates were used to follow the uptake and to determine the endocytic pathway of the protein in Raji cells. The initial steps, contrary to those observed for AFP, did not apparently involve coated pits and vesicles. Small vesicles (approximately 50-60 nm) with electron-dense DBP-horseradish peroxidase reaction products were observed that could fuse with large endosomes. These endosomes appeared dispersed in the cytoplasm with some preferential localization in the Golgi centrosphere region. Pulse-chase experiments showed that only 10% of the uptaken protein was released in a nondegraded form. Accordingly, most DBP molecules accumulated in endosomes should be degraded in lysosomes, instead of being recycled back to the surface, as in the case of AFP. Contrary to malignant B-cells (Raji), the uptake ability for DBP of normal quiescent B-lymphocytes was very low. Specific binding and internalization of DBP-FITC by these cells were observed following mitogen-induced activation. Significant values of uptake were obtained at 37 degrees C after 72 h of incubation in the presence of pokeweed mitogen. The binding of DBP-FITC was partially inhibited in the presence of an excess of unlabeled protein. Taken together, the actual results suggest that DBP receptors are constitutively expressed by malignant B-cells and in a transitory form by normal B-lymphocytes undergoing mitogen-induced activation.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1992

Alpha-fetoprotein-mediated uptake of fatty acids by human T lymphocytes.

The binding to resting and activated T lymphocytes of two radiolabelled fatty acids (oleic and arachidonic) was studied in the presence or in the absence of alpha-fetoprotein (AFP) as carrier protein. Fatty acid binding by resting and activated T lymphocytes was determined at 4 degrees C as a function of the concentration of fatty acid and AFP. Under the conditions employed, the following observations were made: (1) in the presence of AFP, fatty acids (oleic and arachidonic acid) are bound to cells by a two-component pathway; one is a saturable process, evidenced when the fatty acid to AFP (FA/AFP) molar ratio was fixed at 1 and the concentration of the fatty acid and the protein varied from 0.1 to 3.2 microM, and the second is a nonsaturable function of FA/AFP molar ratio and was linearly related to the unbound fatty acid concentration in the medium over the entire range studied; (2) in the absence of AFP, the nonsaturable process appears to be the only component of fatty acid binding; 3) at all tested concentrations of free (unbound) fatty acid in the medium, net fatty acid binding by either resting or activated T cells was considerably greater in the presence than in the absence of AFP; (4) in the presence of AFP, fatty acid binding was much higher in activated T cells than in resting T cells, whereas in the absence of AFP, nonsignificant differences were observed between activated and resting T cells; and (5) the time course of fatty acid and AFP binding at 4 degrees C revealed that, at equilibrium, the number of fatty acid molecules bound to the cell was much greater than that of AFP suggesting an accelerated dissociation of the fatty acid upon interaction of the AFP-fatty acid complex with putative cell receptors. It is concluded to the existence of an AFP/AFP-receptor pathway that facilitates the binding of fatty acids to T lymphocytes, particularly upon their blast transformation. This pathway may fulfill the increased requirement for fatty acids characteristic of proliferating cells and may serve to regulate the endocytosis of fatty acids with modulatory effects on lymphocyte function and to protect cells from their cytotoxic potential when internalized in excess.

Arachidonic Acid↗
PubMed1992

Evaluation of eight serological tests in the diagnosis of human echinococcosis and follow-up.

The ELISA with use of IgG, IgA, and IgE, latex agglutination, indirect hemagglutination (IHA), total IgE, the radioallergosorbent test (RAST), and immunoelectrophoresis (IEP) were carried out to determine the preoperative diagnosis of infection due to Echinococcus granulosus in 131 patients. Eighty-nine patients received follow-up care for 42 +/- 22 months (mean +/- SD); 72 were treated surgically and 17 with mebendazole only. We analyzed 5 +/- 2 serum samples per patient and analyzed each serum sample using the eight tests. IgG ELISA was the most sensitive (up to 94%) and specific (up to 99%) test for the majority of cyst locations in the patient. IEP was positive in only 73% of cases. The combination of IgG ELISA, IHA, and IgA ELISA allowed us to achieve a sensitivity of 81% in cases of pulmonary echinococcosis. IgE and IgA were both responsible for most nonspecific reactions, the former in patients with parasitic diseases other than echinococcosis and the latter in patients with cirrhosis of the liver and malignancies. IgG ELISA and IHA were the most adequate tests for postsurgical follow-up. In patients with favorable clinical outcome, the specific IgG level decreased early toward the end of the first year, although serological positivity could persist beyond 6 years. A rise of IgG level 2 or 3 years after treatment suggested persistent active infection. In patients with mebendazole-associated cure, only tests with total or specific IgE detection seemed to exhibit a strong association with decreasing levels or with negative results.

Adolescent↗
PubMed1992

[Sepsis caused by Mycobacterium tuberculosis in patients with AIDS].

BACKGROUND: Techniques for detecting mycobacteria in blood can be a good alternative for diagnosing tuberculosis in acquired-immunodeficiency syndrome patients (AIDS). PATIENTS AND METHODS: Eleven patients with AIDS and pulmonary tuberculosis, and four controls with AIDS and without tuberculosis were studied. The diagnosis of mycobacteremia was made by the identification of the microorganisms in blood. The method used was a lysis-centrifugation with subsequent stain or culture identification in different media (agar Löwenstein-Jensen, M7H9, M7H11, brain-heart infusion and Sauton broth). RESULTS: In one case, direct staining of sample was positive. The culture results were positive in all 11 patients with tuberculosis and in none of the controls. M7H11 was the media that allows the fastest detection. CONCLUSIONS: This technique can be a good alternative method for tuberculosis diagnosis in AIDS patients. Is easy to perform, relatively fast an with diagnostic performance. It also could be of interest in extra-pulmonary tuberculosis.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Activated human T lymphocytes express albumin binding proteins which cross-react with alpha-fetoprotein.

The kinetics of iodinated human serum albumin ([125I]Hu-SA) and alpha-fetoprotein ([125I]Hu-AFP) binding and endocytosis by resting and phytohemagglutinin (PHA)-activated human T lymphocytes were studied comparatively. The binding of both SA and AFP appeared considerably increased upon blastic transformation. SA, like AFP, binds in a saturable way to the surface of PHA-stimulated human T lymphocytes at 4 degrees C and is endocytosed at 37 degrees C. Two saturation plateaus were observed by incubating at 4 degrees C activated T lymphocytes with [125I]Hu-AFP at different concentrations (10 ng-250 micrograms/ml), while only one saturation plateau was obtained by incubating cells with [125I]Hu-SA in the same conditions. Scatchard analysis of binding data revealed two types of binding sites for Hu-AFP and one for Hu-SA. Competition experiments using proteins of human and bovine origin are in favor of the presence on the surface of these cells of a common binding site for AFP and SA. Pulse-chase experiments showed that internalized [125I]SA was released mainly in a degraded form from the cells, in agreement with detection by ultrastructural cytochemistry of peroxidase-conjugated SA in lysosome-like bodies by ultrastructural cytochemistry. This contrasts with the intracellular pathway of AFP, which as previously described (Geuskens, M., et al., Eur. J. Cell Biol. 50, 418-427 (1989)), moves to tubular-vesicular structures in the Golgi region and is recycled for the most part undegraded.

Albumins↗
PubMed1992

[Antigenic response against PPD and antigen 60 in tubercular patients: single antigen versus the combined test].

We analyze serum samples from 70 patients with pulmonary tuberculosis and 50 healthy individuals. The antigenic activity (IgG) against protein purified antigen (PPD) and antigen 60 (A60) from M. tuberculosis. Thirteen patients were also HIV infected, and three patients had AIDS defined by the presence of disseminated tuberculosis. The test using antigen alone showed a 77% sensitivity and 74% specificity when PPD is used. When A60 was used, both values improved (81% sensitivity, 94% specificity). The use of a combined test (PPD and A60) improves the sensitivity (89%) but reduces the specificity (82%). The HIV infected patients showed similar responses to those of other patients. The combined use of different antigens might be useful for diagnosing tuberculosis.

Acquired Immunodeficiency Syndrome↗
PubMed1992

In vitro and in vivo studies with flutrimazole, a new imidazole derivative with antifungal activity.

1-[(2-Fluorophenyl)(4-fluorophenyl)phenylmethyl]-1H-imidazole (flutrimazole, UR-4056, CAS 119006-77-8) is a new topical imidazole antifungal agent which displays potent broad-spectrum in vitro activity against dermatophytes, filamentous fungi and yeasts, saprophytic and pathogenic to animals and humans (MIC = 0.025-5.0 micrograms/ml). In most of these studies the activity of flutrimazole was comparable to that of clotrimazole and markedly higher than that of bifonazole (MIC differences of greater than or equal to 1 order of magnitude). Tested against Scopulariopsis brevicaulis (8 strains), both flutrimazole and clotrimazole exhibited fungistatic and fungicidal activity, and clotrimazole appeared something less active (MIC = 0.3-2.5 micrograms/ml) than flutrimazole (MIC = 0.15-0.6 micrograms/ml). In animal experiments, topical application of 1% and 2% flutrimazole, as a cream or solution, was highly effective in models of rat vaginal candidiasis and guinea-pig trichophytosis, giving a rate of cured or cured plus markedly improved animals higher than 80%. Flutrimazole shares the mode of action of other imidazole or triazole-containing antifungals, i.e. inhibition of fungal lanosterol 14 alpha-demethylase, as it strongly inhibits ergosterol biosynthesis in a cell-free homogenate of Candida albicans, with an IC50 value of 0.071 mumol/l.

Animals↗
PubMed1992

[Course and prognostic value of nutritional parameters in chronic bronchitis].

We studied the nutritional parameters in 82 patients with chronic airways obstruction (type chronic bronchitis). Midarm muscle circumference was the earliest parameter affected. Patients were admitted to the hospital when his serum albumin had a value under normal. On the other hand, the outpatients had a serum albumin within the normal limits. When the protein deficiency involved serum prealbumin and serum retinol binding protein the patients were admitted to intensive care unit (ICU). The body weight and triceps skinfold were within the normal limits even in icu's patients, so that, both parameters neither reflect the nutrition status nor the severity of the undernutrition.

Aged↗