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S Garcia

Publications and source records attributed to S Garcia.

At least 127 records · Page 7Linked to original sources
PubMed1994

Isolation and characterization of bovine follistatin cDNA.

Seven bovine follistatin (FS) cDNA clones were isolated from a bovine ovarian follicle cDNA library. The predicted amino acid sequences revealed that six of the cDNA clones represented an FS precursor of 344 amino acids which corresponded to a mature FS of 315 amino acids (FS 315), with one cDNA clone containing the entire coding sequence including 180 nucleotides of 5' untranslated sequence. The predicted amino acid sequence of the seventh cDNA clone, which differed in the 3' coding sequence, represented a precursor protein of 317 amino acids, corresponding to a mature FS of 288 amino acids (FS 288). This clone encoded an identical amino acid sequence to the other six cDNA clones except that the C terminal of FS 315 was truncated by 27 amino acids. The sequence of bovine FS was found to contain 36 cysteine residues and 2 potential N-linked glycosylation sites. The predicted amino acid sequence of bovine FS has overall sequence homologies of 98% with ovine FS and 97% with human FS.

Amino Acid Sequence↗
PubMed1994

Fine-needle aspiration of thyroid follicular neoplasm: diagnostic use of thyroid peroxidase immunocytochemistry with monoclonal antibody 47.

BACKGROUND: We previously demonstrated that thyroid peroxidase (TPO) immunocytochemistry with monoclonal antibody 47 can help to differentiate benign (staining score, 80% or more) from malignant (staining score, less than 80%) thyroid nodules on fine-needle aspiration (FNA) samples. In the present study we assessed the use of TPO immunocytochemistry in the cytologic diagnosis of thyroid follicular neoplasms. METHODS: A total of 109 histologically proven follicular tumors were studied. There were 60 microfollicular adenomas, 23 atypical adenomas, 17 oncocytic adenomas, and 9 follicular carcinomas. Adequate preoperative FNA samples were available in all cases. TPO immunocytochemistry was performed on one half of the slides. RESULTS: The staining score was less than 80% in all follicular carcinomas, whereas it was 80% or more in 68 of 100 benign tumors. There was no false negative and 32 false positives for diagnosis of malignancy. The false positives were 10 microfollicular adenomas, 13 atypical adenomas, and 9 oncocytic adenomas. TPO immunocytochemistry has a sensitivity of 100% and a specificity of 68% for screening of follicular cancer. CONCLUSIONS: TPO immunocytochemistry with monoclonal antibody 47 on FNA samples is a highly sensitive and fairly specific method to distinguish benign from malignant follicular neoplasms. This technique can help to reduce the number of surgical procedures for benign thyroid nodules without increased risk of overlooking malignancy.

Antibodies, Monoclonal↗
PubMed1993

Enzymatic DNA amplification (PCR) in the diagnosis of extrapulmonary Mycobacterium tuberculosis infection.

A polymerase chain reaction able to amplify Mycobacterium tuberculosis DNA from clinical samples of extra-pulmonary origin is described. The PCR amplified a 294 base pair DNA fragment spanning positions 5'-782 to 3'-1075 of the 65 kDa M. tuberculosis antigen gene. The procedure enables amplification of target DNA at quantities as low as 1 pg of purified material and less than 1000 mycobacteria present in clinical samples. The reaction amplifies M. tuberculosis DNA as well as Mycobacterium bovis BCG DNA. In 34 extra-pulmonary clinical samples studied, 18 rendered positive results and two false-negative results; compared to classical diagnostic procedures, the sensitivity was 90% and specificity 100%. The PCR approach to diagnosis of tuberculosis of extra-pulmonary origin is a valid diagnostic alternative to classical procedures.

Base Sequence↗
PubMed1993

Thyroglobulin in medullary thyroid carcinoma: immunohistochemical study with polyclonal and monoclonal antibodies.

The presence of thyroglobulin (TG) was investigated by immunohistochemistry with one polyclonal and three distinct monoclonal anti-TG antibodies in 19 primary and 15 metastatic medullary thyroid carcinoma (MTC) cases. In two primary tumors possessing a mixed trabecular and follicular growth pattern, a significant number of tumor cells were positive with the four antibodies in all parts of the tumor; these tumors were considered to be genuine mixed follicular and parafollicular tumors. The 17 other primary tumors looked like "classical" (ie, predominantly compact) MTC. Eight contained tubular or microfollicle-like structures that were consistently TG-negative. Eight contained residual entrapped normal follicles positive with the four anti-TG antibodies. In six cases isolated foci of tumor cells reacted with polyclonal antibody or monoclonal antibody 11. In 10 cases circulating TG stained positively with polyclonal antibody in vascular channels, five cases stained positively for TG with monoclonal antibody 11, four cases stained positively for TG with monoclonal antibody 7, and three cases stained positively for TG with monoclonal antibody 1. In metastases TG was found in tumor cells in only one instance, but positive reactions were obtained in vascular channels and macrophages in several cases. We conclude from this study that there is no genuine secretion of TG in classical, compact MTC, which differs morphologically and functionally from mixed follicular and parafollicular tumors secreting both TG and thyrocalcitonin.

Antibodies, Monoclonal↗
PubMed1993

Programmed cell death in AIDS-related HIV and SIV infections.

One of the difficulties in understanding the complex pathology of human immunodeficiency virus (HIV) infection is to explain the progressive depletion of the CD4 helper T cell population and consequently the destruction of the immune system. Although cytopathic effects of HIV are observed in vitro, they cannot in vivo account for CD4 T cell depletion because relatively few cells are productively infected. Thus immunological mechanisms must be envisaged. We have found that peripheral blood lymphocytes (PBLs) from asymptomatic HIV-infected individuals are primed for a suicide process known as apoptosis or programmed cell death (PCD). DNA fragmentation characteristic of apoptosis was enhanced by stimulation of lymphocytes with ionomycin, a known inducer of apoptosis in suitably primed cells. Identification of the T cell subpopulations programmed for apoptosis indicated that both CD4+ and CD8+ cells died when cultured without stimulation or when polyclonally stimulated with ionomycin. Activation-induced cell death was also observed after stimulation with self-MHC class II-dependent superantigens, namely bacterial toxins from Staphylococcus (SEB), Streptococcus (ETA), and Myocoplasma (MAM) and under these conditions the CD4+ T cells were preferentially affected. To explore whether new macromolecular synthesis were required for apoptosis, various known inhibitors of apoptosis such as cycloheximide, cyclosporin A, Zn2+, or EGTA were tested. Activation-induced apoptosis was found sensitive to these inhibitors, indicating an active mechanism, but apoptosis observed in nonstimulated cultures was not, suggesting that these cells already contained the complete machinery for death. Prevention of apoptosis could be obtained in the presence of a mixture of cytokines and the minimal signal necessary for this prevention was IL-1 alpha and IL-2. Finally, a correlation between PCD and AIDS-pathogenesis was suggested by the comparison of lymphocytes from lentivirus-infected primates suceptible (SIV-infected macaques) and resistant (HIV-infected chimpanzees) to AIDS. Altogether our results suggest that, during HIV or SIV infection, PCD may contribute in vivo to the deletion of reactive T cells after antigenic stimulation.

Animals↗
PubMed1993

Adenomyoepithelioma of the breast. Report of two cases.

The clinical and pathologic findings of two cases of adenomyoepithelioma of the breast are reported. Aspiration cytology was performed in one case and was interpreted as malignant. Conversely, histological features revealed their typical architectural arrangement and immunohistochemical profiles confirmed that myoepithelial (actin and S-100 protein +) and epithelial (keratin and epithelial membrane antigen +) cells were active components in both tumours.

Adenoma↗
PubMed1992

Ultrastructural analysis of the serotonin hyperinnervation in adult rat neostriatum following neonatal dopamine denervation with 6-hydroxydopamine.

Serotonin (5-HT) immunocytochemistry was used at the electron microscopic level to characterize the ultrastructural features of 5-HT axon terminals (varicosities) hyperinnervating the neostriatum of adult rats, 3 months after a neonatal destruction of the nigrostriatal dopamine system by intraventricular 6-hydroxydopamine. 5-HT-immunostained terminals from the anterior half of the hyperinnervated neostriatum were examined in single thin sections, and compared to their counterparts in vehicle-injected controls with respect to shape, size, organelle content, presence of a synaptic membrane differentiation and composition of the microenvironment. The intrinsic and relational features of the 5-HT-immunostained varicosities were essentially the same in 5-HT-hyperinnervated and control tissue. In particular, the frequency with which these varicosities made synaptic contacts was similarly low in both conditions (6-8% for whole varicosities), as already described in normal adult rat neostriatum. The distributional frequency of elements juxtaposed to the 5-HT-immunostained varicosities was also comparable in control and 5-HT-hyperinnervated tissue. However, in both conditions, there were much fewer dendritic spines in the microenvironment of 5-HT varicosities than around unlabeled terminals randomly selected from the same thin sections. This difference seemed entirely due to the numerous axo-spinous synaptic contacts made by the randomly selected, unlabeled varicosities. Together with recent observations on the 5-HT-hyperinnervation of adult rat hippocampus after grafts of fetal neurons, these data lead to the suggestion that mostly non-junctional neostriatal 5-HT terminals are not committed to a specific intratissular microenvironment. This might in part explain why they grow in excess when reinnervating adult tissue after a lesion or a graft.

Aging↗
PubMed1992

Genotoxic potential of crown ethers in mammalian cells: induction of sister-chromatid exchanges.

Crown ethers are macrocyclic polyethers which possess ionophoric properties. These compounds are currently being studied for potential use as pharmaceutical agents as well as antibacterials. Though crown ethers have been shown to be highly toxic in prokaryotes and eukaryotes, there have been few investigations into the potential genotoxicity of these compounds. When sister-chromatid exchanges (SCEs) were quantitated after exposure to crown ethers, the results reflected no significant genotoxic effects on Chinese hamster V79 cells at any of the crown ether concentrations utilized. One crown ether, dicyclohexyl 21-crown-7, did appear to possess antigenotoxic activity. The data on the induction of SCEs by crown ethers reported herein suggest that these compounds are not genotoxic in mammalian cells despite their cytotoxicity.

Analysis of Variance↗
PubMed1992

Isolation and identification of xochitloldione and isoxochitlolone from Cnidosculus urens.

Major components of MeOH extracts from the plant roots of Cnidosculus urens purified by cc and tlc and crystallization were lupeol acetate and the previously unreported compounds isoxochitlolone [1] and xochitloldione [2], which were identified through mass, ir, nmr, and uv spectroscopy and X-ray crystallography. In preliminary testing, isoxochitlolone has been found to be active against Escherichia coli and Staphylococcus aureus.

Anti-Bacterial Agents↗
PubMed1992

Bilateral distribution of aminopeptidase activities in selected structures of a photoneuroendocrine circuit and other rat brain areas.

Provided that soluble aminopeptidases, the most abundant proteolytic enzymes found in brain, are involved in the metabolism of several neuropeptides, their activity could be a reflect of neuropeptide function. Therefore, in order to analyze their rate of participation, we have measured 4 soluble aminopeptidase activities: leucine aminopeptidase, arginine aminopeptidase, aspartate aminopeptidase, and pyroglutamate aminopeptidase, using arylamide derivatives as substrates, in selected structures integrating the photoneuroendocrine circuit related to the melatonin rhythm generating system and other rat brain areas. The regional distribution of all the activities was heterogenous: a 3-fold (leucine-, arginine- and aspartate-aminopeptidase) and 5-fold (pyroglutamate aminopeptidase) difference was observed between the regions with the highest and lowest activity. Significant differences were displayed between the left and right retina for pyroglutamate aminopeptidase and arginine aminopeptidase activities. High levels of pyroglutamate aminopeptidase were evident in the retina and adenohypophysis, which is consistent with a role for thyrotropin releasing hormone in photoreceptive mechanisms, and support its well established role in controlling thyrotropin releasing hormone in anterior pituitary. The presence of a high activity rate of aspartate aminopeptidase in adenohypophysis implies an active participation of angiotensin peptides at this level.

Aminopeptidases↗
PubMed1992

Transplacental immunity to varicella-zoster virus in extremely low birthweight infants.

Sixteen infants in our intensive care nursery (ICN) were inadvertently exposed to an adult who presented the next day with chickenpox. Since a majority of the patients were extremely premature, we were concerned that they might not have received transplacental varicella-zoster virus (VZV) antibody, and consequently would be at risk for contracting chickenpox. Serum samples were obtained from each infant and examined for the presence or absence of VZV antibody. Fourteen of the 16 infants had antibody levels equal to or in excess of 1:16 by indirect fluorescent antibody, including six of eight infants with birthweights equal to or less than 1000 gm, and eight of ten infants with gestational ages equal to or less than 28 weeks. Passive transfer of immunity to VZV appears to be common in infants as young as 24 to 28 weeks' gestation.

Antibodies, Viral↗
PubMed1991

Ultrastructural features of serotonin neurons grafted to adult rat hippocampus: an immunocytochemical analysis of their cell bodies and axon terminals.

Serotonin (5-HT) immunocytochemistry was used at the electron microscopic level to examine 5-HT neurons reinnervating and hyperinnervating the hippocampus of adult rat, three to four months after a total 5-HT denervation and subsequent graft of embryonic raphe cells. The study focused on immunostained nerve cell bodies, dendrites and axon terminals (varicosities) in the core of grafts, and on a large single section sampling of axon terminals from a CA3 and a dentate gyrus sector of the outgrowth, which were systematically compared to the endogenous 5-HT innervation of the same regions described in a companion paper. The shape, size and synaptic investment of the grafted 5-HT somata and their dendrites resembled those of in situ 5-HT neurons. Clusters of small, clear vesicles were sometimes seen along these 5-HT dendrites. 5-HT axonal varicosities were fairly numerous in the core. A few were directly apposed to, or made asymmetrical synaptic contact with the immunostained dendrites and perikarya, but the vast majority showed no indication of junctional specialization (synaptic incidence of 19%, as stereologically extrapolated for whole varicosities). Occasional myelinated 5-HT axons were also present in the core of grafts. In the two outgrowth sectors, the graft-borne 5-HT varicosities were similar in size, content, frequency of synaptic contact and identity of junctional and appositional elements, irrespective of their laminar location. Moreover, none of these parameters were significantly different from those of the endogenous innervation. Notably, in spite of their excessive number, the synaptic incidence of the outgrowth 5-HT varicosities remained inferior to 20%. The similarity between the respective microenvironments of the supernumerary, graft-borne 5-HT terminals and of their normal counterparts could only be explained by a random intratissular distribution of these varicosities in both the normal and the grafted hippocampus. Thus, in spite of their transplantation and growth into an abnormal milieu, and the fact that they hyperinnervated the host tissue, the grafted embryonic 5-HT neurons appeared committed to express a particular set of intrinsic and relational morphological features corresponding to their normal adult characteristics.

5,7-Dihydroxytryptamine↗
PubMed1991

Heparin-associated thrombocytopenia in a patient with polycythemia vera: the importance of a marked drop in platelet count.

The present report describes a patient with polycythemia vera who developed a severe arterial and venous thrombosis caused by systemically administered heparin. An immunologic implication has been proposed as pathophysiological mechanism of this heparin-associated thrombocytopenia and thrombosis syndrome. It is suggested, however, that a strong decrease in platelet count as occurred in this patient leads to a higher chance of developing this complication.

Female↗
PubMed1991

Diurnal variation and left-right distribution of pyroglutamyl peptidase I activity in the rat brain and retina.

The thyroliberin and luliberin contents exhibit a diurnal rhythm within the brain and an asymmetrical distribution of both neuropeptides has been demonstrated in the hypothalamus. Since they have been described as substrates of pyroglutamyl peptidase I, this activity was analysed in several rat brain regions and other structures, in order to investigate its putative diurnal variations and changes in relation to the distribution of these neuropeptides and/or other susceptible substrates. Fluorometric activity was assayed in the retina, pituitary gland, superior cervical ganglia, pineal gland, some selected brain regions, and serum of adult male rats at six different time points of a 12:12 h light:dark cycle, using pyroglutamyl-beta-naphthylamide as substrate. A significant circadian rhythm was demonstrated in the retina, the hypothalamus, and the intermediate-posterior pituitary lobe. In addition, a small but significant asymmetrical distribution of this activity, at certain time points, was disclosed: The activity was higher in the left than in the right retina at 10 h of the light period, whereas it was predominant in the right side at 01 h of the dark period. Furthermore, the activity was higher in the left anterior than in the right hypothalamic area at 13 and 01 h. These results could be indicative of a role of this enzymatic activity in the control of the functional status of its endogenous substrates.

Animals↗
PubMed1991

[Demonstration of an engagement process towards cell death by apoptosis in lymphocytes of HIV infected patients].

Peripheral blood lymphocytes from AIDS patients or from infected asymptomatic individuals display a rapid loss of viability upon culture in a survival medium. Cellular death occurs following endonucleosomal DNA fragmentation (apoptosis), which is preceeded by chromatin condensation and lower staining with orange acridine. This phenomenon is accelerated by compounds known to activate lymphocytes (such as ionophores) and is partly or entirely suppressed by addition of a cytokine crude preparation, enriched in IL2. All together, these results suggest that in vivo a significant fraction of patients' lymphocytes is engaged towards a preapoptosis process resulting from abnormal activation.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Prophylaxis against infection. Single-dose cefonicid compared with multiple-dose cefamandole.

A total of 1489 patients were included in a prospective, randomized study that compared the efficacy of a single dose of cefonicid in 474 patients (Group I) with that of three doses of cefamandole in 510 patients (Group II) and five doses of cefamandole in 505 patients (Group III), for prophylaxis against infection after an operation on bone. The operations involved the insertion of a Moore prosthesis, an Ender and Küntscher nail, a bone-plate, or another device for internal fixation. Patients who had an open fracture or a total joint replacement were not included in the study. The three groups were similar with regard to mean age, sex ratio, duration of preoperative hospitalization, underlying risk factors, and type of operation. The rates of wound infection were not significantly different in the three groups (p = 0.8) or when the rates were stratified according to the type of operation (p greater than 0.3). Staphylococcus aureus and gram-negative bacilli were the most common infecting microorganisms. The rate of mortality related to infection was similar in all three groups (p = 0.2). No adverse side-effects of drugs were encountered. A single preoperative dose of cefonicid, three doses of cefamandole, and five doses of cefamandole were equally effective prophylaxis against infection of the wound in these patients.

Aged↗