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Biomedical subjects

J Espinosa

Publications and source records attributed to J Espinosa.

At least 73 records · Page 4Linked to original sources
PubMed1985

Difference in, and influence of the purification medium on, sensitivity and maximum response of peritoneal and pleural mast cells stimulated by certain polyamines.

The actions of the polyamines compound 48/80, poly-l-lysine and polymyxin B on rat pleural and peritoneal mast cell secretion have been studied. Unpurified pleural mast cells released more histamine than peritoneal mast cells when stimulated by submaximal concentrations of compound 48/80 and poly-l-lysine, but the same profile of response was observed with polymyxin B in both populations. Dose-response studies of peritoneal and pleural mast cells purified with Percoll and Ficoll and stimulated by polymyxin B showed a decreased sensitivity and decreased maximum response of peritoneal cells when Percoll was used. The maximal response of pleural cells and the sensitivity of peritoneal cells were affected only slightly by Ficoll.

Animals↗
PubMed1984

Milk progesterone radioimmunoassay using radioiodinated tracers: a rapid and reliable assay system.

Both the validity and practicability of a direct progesterone radioimmunoassay based on radioiodinated progesterone tracers were studied. The results obtained show the reliability of the assay; when compared with assays based on 3H-progesterone tracers there are fewer steps for assay execution, saving time and reducing the number of reagents used. Various commercially available 125I-progesterone tracers were assayed, and only those with an 11 alpha-hemisuccinate bridge were suitably bound by antisera raised against progesterone-bovine serum albumin conjugates having identical bridge structure. The bridge effect caused no observable alteration in validity parameters. Finally, our results support the utility of this assay as a practical method of early diagnosis of pregnancy and as a reliable experimental technique to monitor cow ovarian function.

Animals↗
PubMed1984

Changes in serum LH and FSH following preovulatory administration of ethanol in rats.

The effect of different single doses of ethanol (1.0, 2.0 and 4.0 g/kg) on serum LH and FSH has been studied in rats treated during preovulatory periods (18th h of diestrous). High doses of ethanol (2.0 and 4.0 g/kg) decreased serum LH levels at the 18th h of proestrous, 24 h after ethanol administration, inhibiting the preovulatory LH surge. No changes were observed in FSH levels. These effects could be mediated through the inhibition of the hypothalamic releasing factors.

Animals↗
PubMed1984

[Effect of ethanol in the pre-ovulatory period on the ovarian cycle, progesterone and estradiol in the rat].

The effect of high doses of ethanol (2 and 4 g/kg) administered to rats in pre-ovulatory periods (18th hour of diestrus) was studied. Plasma levels of estradiol and progesterone were measured at 10 hours of oestrus and changes in the ovarian cycle and the number of mature follicles were recorded. Compared with the control group, the receptive phase of estrus of the treated animals was longer lasting over 2 to 3 days. There was also an increase in the number of mature follicles as well as an increase in the plasma level of estradiol on the morning of estrus. Progesterone values showed no significant variations. Ethanol administered at the 18th hour of diestrus inhibits ovulation but not follicle development and allows the maintenance of high levels of estrogens on the morning of estrus. As a result the keratinization of the vaginal epithelium and the estrus phase are prolonged by 2 or 3 days.

Animals↗
PubMed1983

Mutagenicity of antiamebic and anthelmintic drugs in the Salmonella typhimurium microsomal test system.

4 amebicides (chloroquine diphosphate, diiodohydroxyquin, iodochlorohydroxyquin and dehydroemetine) and 6 anthelmintics (bephenium hydroxynaphthoate, 4-hexylresorcinol, mebendazole, niclosamide, pyrantel pamoate and pyrvinium pamoate) were tested for mutagenicity in the Salmonella typhimurium microsomal test system. Frameshift mutations were induced by dehydroemetine and niclosamide following activation by microsomal enzymes, while pyrvinium pamoate induced both frameshift and base-pair substitution mutations with or without metabolic activation. The urine of mice treated with dehydroemetine or pyrvinium pamoate showed no mutagenic activity. However, urine obtained from mice treated with niclosamide was mutagenic in strains TA98 and TA1538. The fluctuation assay showed chloroquine diphosphate to be mutagenic in TA1537, a strain which detects frameshift mutations.

Amebicides↗
PubMed1983

[Isolation of mastocytes from rat peritoneal fluid using continuous Ficoll gradients].

A method for mast cells purification from rat peritoneal fluid is described. The method consists of a continuous Ficoll gradient between 20 and 22,5% (w/v) Ficoll and the cells are obtained with an 88% retrieval. Purity and viability were of 95% and 97% respectively. The cells so purified were functional against the compound 48/80 and the spontaneous secretion value was less than 8%.

Animals↗
PubMed1983

[Secretory activity of mast cells in the presence of cholinergic agonists].

Mast cells from rat peritoneal fluid were studied under cholinergic stimulus. The cells were purified by a continuous Ficoll gradient and were challenged with acetylcholine and carbamylcholine. The preparations showed the typical dose-response pattern against compound 48/80 with a dose interval of 0.5-1 microM that clearly increased the secretion. However, the histamine release elicited by increasing concentrations of acetylcholine and carbamylcholine was of little magnitude and similar for all the concentrations; this kind of response has not a dose-response profile and does not appear to be explained by the presence of a cholinergic receptor on the mast cell cellular membranes. The cholinergic agents neither stimulated directly the mast cells nor did they cause any variation in the 48/80 response. The histamine release pattern obtained with these agents cannot support the hypothesis of a primary cholinergic receptor on mast cells. However, if such receptor existed, its action could only be of secondary importance, and in fact such action was not manifested with the compound 48/80.

Acetylcholine↗
PubMed1975

Hypothalamic-pituitary-gonadal function in patients with myotonic dystrophy.

Gonadal function was studied in three post-pubertal siblings (two male and one female) and one unrelated male patient with myotonic dystrophy. The diagnosis was confirmed in all cases by electromyography and muscle biopsy. Basal levels of plasma immunoreactive LH, FSH, testosterone, and estradiol were measured. Hypothalamic, pituitary, and gonadal reserve and responsiveness were evaluated by clomiphene, LHRH, and HCG tests. Histologic examination of gonadal biopsies was also performed. The results showed that gonadal failure present in the four patients had different characteristics. In the same family, hypothalamic amenorrhea was observed in the female patient, and hypothalamic eunuchoidism and hypergonadotropic hypogonadism with marked tubular and leydig cells failure in the male patients. The non-related male patient had hypergonadotropic hypogonadism with tubular failure but with a compensatory leydig-cell hyperplasia. These data are interpreted as demonstrating different expressivity of the hypogonadism associated with the same inherited muscle disease.

Adult↗