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Biomedical subjects

S Salazar

Publications and source records attributed to S Salazar.

At least 19 recordsLinked to original sources
PubMed2001

Evaluation of estrogenic effects of municipal effluents to the freshwater mussel Elliptio complanata.

Municipal effluents are an important source of estrogens to the aquatic environment. The purpose of this study was to examine the estrogenicity of municipal effluents to the indigenous freshwater mussel, Elliptio complanata. First, estradiol-binding sites in gonad homogenates were characterized to determine the binding affinity and specificity of estrogens. Mussels were exposed to increasing concentrations of a municipal effluent for 96 h at 15 degrees C. In another experiment, mussels were placed in cages and submerged for 62 days at 1.5 km upstream and 5 km downstream of a municipal effluent plume in the St. Lawrence River. Mussels were harvested for assessment of vitellogenin-like proteins in the hemolymph and determination of total lipid, carbohydrate and protein in the gonad. The presence of specific estrogen-binding sites was found in both male and female gonads. Binding of estradiol to cytosol proteins reached saturation, yielding a dissociation constant of 0.4 nM. Vitellogenin (Vg) levels increased significantly in both the hemolymph and the gonad after exposure to the effluent. Moreover, females appeared to be more sensitive than males to producing Vg. Mussels exposed in situ to contaminated surface waters had higher levels of Vg at the downstream site, again, females had higher levels of Vg than did males. On the other hand, lipid and sugar levels in male gonads were significantly increased at the downstream site. Moreover, mussels at the downstream site had decreased shell growth length and increased total and soft tissue weights. We conclude that municipal effluents contain bio-available xenoestrogens at levels sufficient to elicit effects in freshwater mussels.

Animals↗
PubMed2000

Clinical findings in a patient mosaic for a supernumerary ring chromosome 20.

Marker chromosomes present a problem in genetic counseling because there are often no clear phenotype-karyotype correlations. We present the clinical findings in a patient who is mosaic for a supernumerary marker chromosome 20 determined by fluorescence in situ hybridization (FISH) and compare these findings to others reported in the literature.

Abnormalities, Multiple↗
PubMed1999

Diminished levels of T cell receptor zeta chains in peripheral blood T lymphocytes from patients with systemic lupus erythematosus.

OBJECTIVE: To examine the expression of molecules known to participate in early T cell receptor (TCR)/CD3 signaling in peripheral blood (PB) T lymphocytes from patients with systemic lupus erythematosus (SLE). METHODS: Signaling molecules were analyzed by immunoprecipitation and Western blotting of unstimulated PB T lymphocyte cell lysates from SLE patients, non-SLE disease controls, and healthy controls. Flow cytometry was used for analysis of the expression of membrane markers in intact cells. RESULTS: PB T lymphocytes from SLE patients showed diminished levels of TCRzeta chains. This was not due to trapping of these molecules in the cytoskeleton, nor was it dependent on the presence of monocyte/macrophages. There was normal expression of CD3epsilon chains and normal assembly of TCR/CD3 complexes in membranes. We observed a lack of expression of TCRzeta chains in in vitro cultures of SLE T cells, and reversal of the defective expression in some patients by culturing T cells in the presence of NH4Cl. CONCLUSION: Blood lymphocytes from SLE patients have a diminished expression of TCRzeta chains that may be related to enhanced degradation in the lysosomal compartment. The defective expression of these molecules may alter signal transduction via the CD3 pathway and contribute to abnormal T cell responses in T lymphocytes from SLE patients.

Adolescent↗
PubMed1999

Incidence of irregular cycles among Mayan women who reported having regular cycles: implications for fertility awareness methods.

Despite the low contraceptive prevalence among the Mayan population of Guatemala, past research has found interest in natural methods. A calendar rhythm method with a simple blanket rule would appear to be preferable to more complicated methods. Under a blanket rule, the number of days of abstinence is predetermined and all couples are instructed to abstain during the same interval of the menstrual cycle. However, regular menstrual cycles may be key to successful practice of a calendar method. A database of 880 cycles of 301 women of the Guatemalan highlands was analyzed to determine the length and regularity of menstrual cycles in this population.

Adolescent↗
PubMed1998

Protein tyrosine kinase activity in T lymphocytes from patients with systemic lupus erythematosus.

We have recently observed an abnormal pattern of protein tyrosine phosphoryl-ation in resting T lymphocytes obtained from peripheral blood of patients with systemic lupus erythematosus (SLE). To examine whether these findings may be related to dysregulated protein tyrosine kinase (PTK) function, we tested the relative amount and enzyme activity of the main PTKs involved in the earliest signalling steps triggered via the CD3 pathway. Cell lysates from peripheral blood T cells in SLE patients showed lower amounts of p59(fyn) and p56(lck) as shown by immunoblot. In contrast, the amount of ZAP-70, a PTK of the syk family, was comparable in both groups. However, p59(fyn) immuno-precipitates obtained from unstimulated peripheral blood SLE T cells showed enhanced PTK activity as compared to controls, whereas the PTK activity of p56(lck) and ZAP-70 molecules was comparable in both groups. The unchecked activity of the TCR/CD3-associated src kinase p59(fyn) may alter the balance needed for regulated T cell responses in SLE patients.

Adult↗
PubMed1998

[Central neurocytoma].

INTRODUCTION: A central neurocytoma (CN) is a rare tumor, of neuronal origin, well-differentiated and found intraventricularly. It mainly affects young adults. Firm diagnosis is made on immunohistochemical (IHQ) and ultrastructural studies, since on optic microscopy it is similar in appearance to an oligodendroglioma or to an ependymoma. PATIENTS AND METHODS: We studied 4 cases, three after surgical resection and one on autopsy. The average age was 29, ranging from 3 to 63. Both sexes were equally affected. In all cases IHQ techniques were used (GFAP, neurofilament, synaptophysin and specific neuronal enolase) and they were studied by electron microscopy. RESULTS: IHQ was negative for GFAP and neurofilament, but intensely positive for synaptophysin and specific neuronal enolase. On ultrastructural study there were few neurofilaments, microtubules and dense central granules typical of neural differentiation. CONCLUSIONS: The findings in our cases lead to diagnosis of NC and confirm that this tumor is a distinct clinicopathological entity.

Adolescent↗
PubMed1996

Antifertility effects of (+)-S-2-amino-6-iodoacetamidohexanoic acid (2-AIHA) in female rats.

(+)-S-2-amino-6-iodoacetamidohexanoic acid (AIHA), an irreversible inhibitor of the ornithindecarboxylase and extrahepatic arginase enzymatic activities with antineoplasic properties, was evaluated for antifertility activity in pregnant rats by oral administration at different periods of gestation. Our results showed that doses of 10 and 20 mg/kg of AIHA orally administered produced a contraceptive effect when it was administered from days 2 to 5, and 8 to 12 of gestation, respectively. The gestation time was slightly shortened when AIHA was applied from day 15 until labor. No sign of external malformations in fetuses was observed. On the other hand, AIHA did not affect the total length of oestrous cycle at the same dosage level used to interrupt pregnancy. In ovariectomized immature rats, neither changes in uterine weight, premature vaginal opening, or cornified cells were found. However, AIHA enhanced the estradiol-induced increase in uterine weights when both were concomitantly administered.

Abortifacient Agents↗
PubMed1996

Effect of Spirulina maxima consumption on reproduction and peri- and postnatal development in rats.

Spirulina maxima, an edible micro-organism useful in human nutrition, was examined for its effect on general reproductive performance and for peri- and postnatal toxicity in rats at levels of 0, 10, 20 and 30% (w/w) incorporated into the diet. There was no reduction in body weight gain in males or females and no deaths or clinical signs of toxicity. Treatment was not associated with any adverse effect on any measure of reproductive performance, including male and female fertility and duration of gestation. There was no increase in the number of abnormal pups at caesarean section or at birth. S. maxima consumption did not result in adverse effects on developmental markers of the pups.

Animals↗
PubMed1995

Evaluation of the teratological potential of the new antihypertensive 5-methoxytryptamine, beta-methylcarboxylate hydrochloride (indorenate) in mice.

5-Methoxytryptamine, beta-methylcarboxylate hydrochloride (indorenate), a new antihypertensive agent, was examined for teratogenic-embryotoxic effects in the mouse at doses of 0 (control), 10, 20, 40, and 80 mg/kg/day. The compound was administered by gastric intubation on days 6-15 of gestation. On day 17, the dams were sacrificed, the number of live, dead, and resorbed fetuses recorded and mean pup weight determined. Teratological evaluation was carried out by visual inspection, alizarin red staining of the skeleton and Wilson's sections. Signs of overtoxicity in mothers were found in the high-dose groups. There were no differences between control and indorenate-treated groups in the number of implantations, live fetuses or anomalies. However, an embryotoxic effect was observed at 40 and 80 mg/kg, shown by increased resorptions and lower weight of pups at the higher dose.

5-Methoxytryptamine↗
PubMed1994

Evaluation of the toxic and teratogenic potential of the anticonvulsant drug 4-hydroxy, 4-ethyl, 4-phenylbutyramide in mice.

The toxicity profiles of the phenyl alcohol amides: 4-hydroxy, 4-ethyl, 4-phenylbutyramide (HEPB) and two lower homologous: 3-hydroxy, 3-ethyl, 3-phenylpropionamide (HEPP) and 2-hydroxy, 2-ethyl, 2-phenylacetamide (HEPA) were studied in mice. TD50 value was determined by oral administration and LD50 by oral and intraperitoneal routes. The results indicate that HEPP is less toxic than the others, both of which had very similar toxicity. Furthermore, the teratogenic potential of HEPB was investigated in mice after oral administration. The compound was administered on days 6-15 of gestation at doses of 0, 5, 25, 50 or 100 mg/kg of weight. On day 17 of pregnancy the mice were sacrificed and the pups examined. An increase of body weight in both mothers and fetuses was observed at 25 and 50 mg/kg and a decrease was found in mothers receiving 100 mg/kg, as a sign of maternal toxicity. Considering the litter data, embryotoxicity and fetotoxicity were only shown at the highest dose. However, the HEPB treatment did not result in malformations of live fetuses or resorptions when the implantations were considered as the individual entity.

Abnormalities, Drug-Induced↗
PubMed1993

Effect of moderate exercise on proliferative responses of peripheral blood mononuclear cells.

We studied the effects of 30 minutes of exercise on T lymphocyte counts and proliferative responses of peripheral blood mononuclear cells (PBMC) in 25 runners. Exercise resulted in a T lymphocytosis in the immediate post-exercise period in all subjects (p < 0.001), and reduced CD4+/CD8+ ratios in 22/25 subjects (p = 0.001). The change was due primarily to a 2.2-fold increase in CD8+ cells (p < 0.001). Exercise also reduced PBMC mitogenic responses to phytohemagglutinin (PHA) in 13/14 subjects (p = 0.049), and to pokeweed mitogen (PWM) in 11/14 subjects (p = 0.022), but not to concanavalin A. Postrun sera from 5 of 6 subjects inhibited PHA but not PWM responses of resting autologous PBMC with normal CD4+/CD8+ ratios (p < or = 0.05): indomethacin and monocyte depletion blocked the serum inhibition (p = 0.003, p = 0.0006, respectively). We conclude that post-exercise suppression of mitogenic responses to PHA is due to the release of a serum factor(s) capable of inducing prostaglandin synthesis by circulating monocytes, whereas exercise-induced suppression of PWM responses depends primarily on the reversal of CD4+/CD8+ ratios.

Adult↗
PubMed1993

[Complete testicular feminization syndrome. Report of a case].

A case of complete testicular feminization (Morris syndrome) in a male pseudohermaphrodite is described. The results of the hormone analyses and the histological features of the resected gonad are presented. The literature is reviewed with special reference to whether gonadectomy should be performed in the pre or post-pubertal period. We advocate early castration because of the high incidence of germ cell neoplasia and the possibility of virilization in case of incomplete androgenic resistance. Our approach is based on the satisfactory feminization achieved by exogenous estrogen therapy.

Adolescent↗
PubMed1992

Effect of myotonia induced by anthracene-9-carboxylic acid on mitochondrial calcium, plasma creatinine-phosphokinase and aldolase activity in the rat.

The frequent association of myotonia with dystrophy and the knowledge that calcium is increased in injured skeletal muscle cells suggest a possible relationship between cell calcium and myotonic alterations. This investigation has been performed to study the role of calcium in experimental myotonia induced by anthracene-9-carboxylic acid (9-AC) in rats treated with several regimens of food and exercise. Thirty-two rats were divided into 4 groups of 8 rats each, one control and 3 experimental groups. The treatments included caffeine plus exercise (group 2), and a calcium-rich diet (group 3); these procedures were designed to increase intracellular calcium; another group was treated with 9-AC as a myotonia-inducer (group 4). The treatment for all groups lasted 60 days. No significant differences in plasma sodium, potassium, chloride and calcium between control and experimental groups were observed. Whole muscle calcium in wet tissue samples did no change with any treatment. On the contrary, mitochondrial calcium showed a significantly higher concentration in group 3 and 4. CPK and aldolase activities in groups 1, 2 and 3 were similar; but in group 4 these enzyme activities were significantly higher (p less than 0.05). The electrical and mechanical responses were not altered in any rat with any experimental treatment. Our data suggest that myotonia is a predisposing factor for an altered mitochondrial calcium homeostasis in this model; in addition, the enzyme activities of CPK and aldolase were increased in the rats of group 4 implicating that myotonia is a crucial factor in the development of enzymatic abnormalities.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗