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Biomedical subjects

E Ortega

Publications and source records attributed to E Ortega.

At least 181 records · Page 10Linked to original sources
PubMed1988

Detection of cell surface rubella virus antigens in Vero cells with Staphylococcus aureus rich in protein A.

The presence of cell surface rubella antigen was used to verify and monitor viral replication in Vero cell monolayers. Viral antigen was observed in infected cells by the adherence of Staphylococcus aureus sensitized with immune anti-rubella sera. The staphylococci specifically bound to infected cells were Gram-stained and observed using light microscopy. The minimum titer of IgG antiviral hemagglutinin required for sensitizing the bacteria was 3.9 IU/ml. The specificity of the assay was demonstrated by treating the infected cells with bacteria sensitized with normal sera, by treating the mock-infected cells with staphylococci sensitized with either immune or normal sera, and by sensitizing the bacteria with immune sera from which anti-rubella antibodies had been removed. Viral antigens were detected from day 2-9 post-infection. The sensitivity of the assay in verifying and monitoring viral propagation was comparable to the titration of viral particles of hemagglutination. The assay is specific, rapid, simple and can be performed in laboratories with minimal equipment.

Animals↗
PubMed1988

[Effects of age and obesity on the conversion of androstenedione to estrone in postmenopausal women].

The effects of aging as well as body weight on conversion of circulating Androstendione (A) to Estrone (E1) in 21 postmenopausal women of different ages and body weights have been studied. Serum concentration of A and E1 were measured by RIA. The E1/A ratio was correlated with total body weight, body mass index, excessive body weight, age and years after cessation of menstruation. The results show that the E1/A ratio was significantly correlated with total body weight, body mass index and excessive body weight. In contrast the E1/A ratio is not significantly correlated with age or years after cessation of menstruation.

Aging↗
PubMed1987

CT demonstration of an aortoesophageal fistula.

A case of aortoesophageal fistula (AEF) is reported in a patient with esophageal bleeding resulting from ingestion of a foreign body. CT showed a saccular aneurysm in close proximity to the esophageal lumen at the level of the bleeding site. AEF has not previously been described on CT.

Aged↗
PubMed1987

Antibody heterogeneity: theoretical and experimental evaluation of a simple procedure to describe differing affinities in hapten binding reactions.

Heterogeneity in antibody binding affinity for hapten is easily and comprehensibly described by plotting the histogram of delta r, the change in the fraction of occupied active sites, vs the logarithm of the concn of free ligand. Computer simulations of binding reactions revealed that multimodal histograms occur only if differences in affinity are greater than 10-fold. Otherwise, the delta r histogram closely approximates a normal distribution, the variance of which increases with increasing heterogeneity. In biochemical experiments delta r histograms successfully detected mixtures of anti-DNP antibodies of varying affinities as well as changes between early and late anti-DNP immune responses in rabbits immunized with or without Freund's complete adjuvant.

Animals↗
PubMed1987

Testosterone implants into the lateral septum of male rats, a positive effect on LH and FSH secretion.

After two days, testosterone implanted into the lateral septum increased serum levels of LH and FSH in male Wistar rats. As measured by RIA, LH in animals with testosterone implanted in them in comparison to those with an empty cannula was 0.220 +/- 0.015 vs. 0.111 +/- 0.019 ng/ml; p less than 0.001 and FSH was 3.20 + 0.21 vs. 1.50 + 0.21 ng/ml; p less than 0.001. Serum testosterone was not increased to a statistically significant extent by the implants (4.12 +/- 0.54 vs. 2.87 +/- 0.42 ng/ml; ns). It was concluded that testosterone or possibly one of its metabolites acting in the lateral septum facilitates the release of LH and FSH.

Animals↗
PubMed1987

[The relationship between Ca++ ions and a protein specific to cromolyn in the degranulation of mast cells and basophils in the rat].

Previous research has shown that cromolyn (disodium cromoglycate) binds specifically to the membrane of rat mast and basophil leukemia (RBL) cells, forming a ternary complex with Ca++, blocking of the Ca++ results in inhibition of histamine release upon immunologic triggering. The specific cromolyn binding protein (CBP) has been isolated by using its high affinity form cromolyn. Specific monoclonal anti CBP antibodies have been obtained in mice and polyclonal anti-cromolyn antibodies in rabbits. These antibodies have been used for further purification and characterization of the CBP. Experiments on RBL cell lines have shown that CBP is essential for Ca++ influx and histamine liberation upon immunologic triggering by these cells. Variant CBP deficient RBL do not take up Ca++ and do not degranulate in response to immunologic triggering but their ability to respond normally can be induced by incorporating CBP into their membranes with help of Sendai virus carrier vesicles. This shows that CBP plays a crucial role for the RBL cells Ca++ influx and histamine release following IgE crosslinking.

Animals↗
PubMed1986

[Influence of body weight on gonadotrophins and steroid hormone levels in menstruating women].

In order to study the effect of obesity or underweight on gonadotropins and steroid hormone levels, serum concentrations of FSH, LH. Testosterone, Estradiol, Estrone, 17-OH-Progesterone and SHBG were measured by RIA in obese, underweight and control women, all menstruating in the follicular phase. Serum concentrations of all parameters measured did not differ significantly in the underweight and control groups. All obese women had higher levels of estrone than the control group, and only obese patients with a body mass index above 39 showed a lower SHBG level than that of the control group. The data suggest that the increased levels of estrone could play a role in the amenorrhea of obese women.

Androgens↗
PubMed1985

[Hypothalamo-hypophyseo-gonadal axis in individuals with chronic renal insufficiency subjected to hemodialysis].

The role of pituitary and sexual hormones in 21 patients with chronic renal failure (CRF) and related impotence and loss of libido who were being treated by hemodialysis and in 15 normal male controls has been studied. In both groups the serum levels of FSH, LH and TSH, PRL before and after injection of both LHRH and TRH were measured as well as the basal levels of Testosterone (T) and Estradiol (E2). The results show similar values for testosterone in both groups and statistically significant higher basal values for FSH, LH, TSH and PRL and lower basal values for E2 in CRF patients.

Adult↗
PubMed1985

Calcium metabolism in post-menopausal women.

To investigate some parameters involved in postmenopausal calcium metabolism we have measured FSH, LH, estradiol (E2), parathyroid hormone (PTH) calcitonin (CT), 25-hydroxy-vitamin D3 (25-OH-D3), total calcium (CaT) and ionic calcium (Ca++) serum levels in 20 healthy postmenopausal women and 20 premenopausal women. The results reported show that the decrease of estradiol levels are associated with a significant decrease in 25-OH-D3 serum levels, possibly as result of a lower concentration of vitamin D binding protein, which is extremely sensitive to changes in oestrogen levels. The PTH levels were similar in both groups studied, which might be explained together with increased ionic calcium levels in postmenopausal women, by decreased parathyroid sensitivity to the blocking action of Ca++.

Adult↗
PubMed1984

Role of the septum on LH, FSH and prolactin secretion in male rats.

Serum concentrations of luteinizing hormone (LH) follicle-stimulating hormone (FSH), prolactin (PRL) and testosterone were measured by radioimmunoassay in male Wistar rats: (a) Four days after a septal lesion (n = 19) and (b) Just following electrical stimulation of the septum (n = 15). Septal lesions induced a significant decrease in serum LH (16.37 +/- 2.01 vs. 30.27 +/- 2.08 ng/ml; p less than 0.001) and testosterone concentrations (0.53 +/- 0.05 vs. 1.01 +/- 0.14 ng/ml; p less than 0.02). No significant changes were observed for FSH or PRL levels. Electrical septal stimulation induced an increase in serum levels of LH (211.5 +/- 46.4 vs. 29.6 +/- 11.5 ng/ml; p less than 0.01) and FSH (703 +/- 83 vs. 378 +/- 57 ng/ml; p less than 0.01), without changes in PRL or testosterone concentrations. From these data we conclude that in male rats the septum may play a role in the mechanisms controlling gonadotropins release by the anterior pituitary gland.

Animals↗
PubMed1984

Effects of sulpiride on levels of FSH, LH and steroid hormones.

In order to study the effects of prolactin upon the gonadotrophins and steroid hormones, hyperprolactinaemia was induced by the administration of sulpiride. 12 men between the ages of 18 and 20 were given 3 capsules of 50 mg of sulpiride daily for a period of 15 days, and the following parameters being measured before and after the treatment: (prolactine, FSH, LH, testosterone, estradiol, ACTH and DHEA-S) by RIA, (cortisol) by fluorimetry and (etiocholanone, androsterone, pregnandiol, pregnantriol, pregnantriolone, 11-keto etiocholanone and 11-OH androsterone) by gas chromatography. Our results show that on termination of the treatment there was a significant rise in the prolactin and DHEA-S serum levels and a drop in the FSH serum levels but not of LH. In addition there was a marked increase in all the androgen levels studied, (etiocholanone, androsterone and 11-keto etiocholanone) with the exception of testosterone.

Adolescent↗
PubMed1983

LHRH test in ovariectomized women with and without treatment of sex hormones.

The modulatory effect of sex hormones on the LHRH test, has been studied on ovariectomized women, randomly divided into groups which received estrogen (E2), progesterone (P) and E2 + P respectively. One group was left untreated. Menstruating women in follicular phase were also studied. The LHRH test was performed on all women and FSH, LH levels were measured in the blood. The LH levels in the blood following the LHRH test showed an increase in all the groups under investigation, including the ovariectomized untreated one. This suggests that, after ovariectomy, the hypophysis does not reach its maximum capacity for gonadotrophin release. The FSH response to the LHRH test was very low in all the groups studied, including the ovariectomized without treatment. It thus could be suggested that FSH needs other stimuli besides LHRH for its physiological release.

Adult↗
PubMed1980

Relationships between eating rate of sheep and live weight gain, weight and fill of the gastrointestinal tract.

Nine ewe and eight wether weanling lambs were fed a pelleted diet containing 60% roughage and 40% concentrate for 12 h/day. Feed consumption (FC) was measured during the first 30 and 60 min (FC-30, -60). Total daily consumption (FCT) was also measured. With these data, feed efficiency (FE), eating rate index (ERI = FC/BW.75) and propensity to eat (percentage FC/unit of time) were calculated. After the completion of these studies, the lambs were slaughtered and weights of the full gastrointestinal tract (GIT) organs, empty organs and wet digesta were obtained. Dry digesta in the organs were estimated from samples of oven-dried digesta. Respective values for males and females were: FE, 6.36 and 7.50 (P less than .01); average daily gain (ADG), 285 and 230 g (P less than .02); FC-30, 597 and 488 g (P less than .05), and FC-60, 706 and 583 g (P less than .05). Significant correlations were found only for females for FC-30 with FCT, ADG with FE and FC-60 with FE (P less than .05). Significant correlations of ERI-30 and ERI-60 with ADG and FE were also observed for the combined sex data. Correlations between eating rate terms and organ or digesta weights were significant only for some reticulorumen (RR) and abomasal parameters. When data from the GIT were correlated with animal performance (FC, ADG, FE), the highest correlations observed were generally for females. Correlations with organ or digesta weights tended to be highest for the small intestine (SI) and ADG; these were followed by values of about equal magnitude for RR organ or digesta weights and ADG or FE. The highest correlations were those between ADG and full organ weight of the SI for males (.86, P less than .01) and between ADG and wet digesta weights of the SI for females (.86, P less than .01). It is concluded that organ and (or) digesta weights of the SI are highly related to animal performance and may be as important as the RR in affecting voluntary feed consumption of pelleted diets.

Animal Feed↗
PubMed1978

[Hypophyso-gonadal function in infancy. From newborn to puberty (author's transl)].

Serum levels of testosterone, follicle stimulating hormone and luteinizing hormone have been measured in 216 healthy children (104 boys and 102 girls) divided in 9 groups from newborn to puberty. Testosterone serum concentrations were significantly higher in boys than in girls during the first 4 months after birth. Testosterone values were highest in 1 to 2 month old boys. Serum concentrations of both FSH and LH changed in different patterns in both sexes. During the first 4 years FSH concentrations were significantly higher in girls than in boys. During the first 4 months, however, LH concentrations were higher in boys than in girls.

Adolescent↗
PubMed1977

Pharmacokinetics of mercaptopurine.

The anatomical distribution of mercaptopurine was investigated in rats at dose levels of 2.5 and 25 mg/kg iv. The plasma and tissues were analyzed by radioisotopic dilution and spectrofluorometric techniques. The tissue-plasma ratios were: liver-plasma, approximately 4.0; kidney-plasma, approximately 2.4; spleen-plasma, approximately 1.7; muscle-plasma, approximately 1.4; gut lumen-plasma, approximately 3; and bone marrow-plasma, approximately 0.35. Physiologically based pharmacokinetic models were developed to simulate concentrations of mercaptopurine in plasma, kidneys, liver, muscle, spleen, bone marrow, and gut lumen. The agreement between experimental and predicted plasma and tissue profiles was good. Human plasma levels of mercapto-purine were predicted and, when compared with clinical data, demonstrated reasonable agreement.

Animals↗