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S Acosta

Publications and source records attributed to S Acosta.

30 records · Page 2Linked to original sources
PubMed1996

Diazoxide and cyclothiazide convert AMPA-induced dark cell degeneration of Purkinje cells to edematous damage in the cerebellar slice.

Using the in vitro cerebellar slice preparation from young rats (8-12 days old), AMPA produced in addition to dark cell degeneration (DCD), an edematous type of toxicity (edematous damage; ED) in a minority (35%) of Purkinje cells. The intent of this study was to evaluate whether AMPA receptor desensitization is a primary factor that governs the type of toxicity induced by AMPA in the in vitro cerebellar slice preparation. Both the competitive and noncompetitive AMPA antagonists CNQX and GYKI 52466, respectively, blocked ED when given during the entire protocol (30 min AMPA exposure followed by 90 min of recovery). Cyclothiazide (100 microM) and diazoxide (500 microM), two antagonists of AMPA receptor desensitization reversed DCD and unveiled a fulminating ED. Lowering Na+ and lowering Cl- proved effective in blocking ED, whereas removal of Ca2+ proved to be ineffective. Kainate (KA) (30-100 microM) produced only 50% as much ED as AMPA. This study indicates that AMPA can elicit more than one type of degeneration in the same neuronal population and that a primary governing factor in determining which toxicity is expressed seems to be the ability of AMPA receptors to desensitize.

Animals↗
PubMed1996

Exposure to threshold doses of nicotine in utero: III. Augmentation of the prolactin and ACTH response to 8-OH DPAT by desipramine treatment is compromised in adult male offspring.

Gravid female rats were injected subcutaneously with saline (SAL) or nicotine (3.0 mg/kg and 0.05 mg/kg, bid) from days 14-21 of gestation. Adult 105-day old male offspring from each of the three groups were treated daily with saline or desipramine (DMI) (10 mg/kg, sc) for 14 days. Twenty-four hours after the last injection, animals were challenged with saline or 8-hydroxy-2- (di-n-propylamino) tetralin (8-OH DPAT) (0.1 mg/kg, sc), a serotonin IA(5-HT(IA)) agonist, and plasma prolactin and ACTH concentrations were measured 15 minutes later. DMI treatment augmented both the prolactin and ACTH responses to 8-OH DPAT in the SAL controls. Neither the prolactin nor the ACTH response was augmented significantly in the animals exposed prenatally to either nicotine dosage regimen, although there was a strong trend for the augmentation to occur in the low-dose nicotine exposed animals. The results indicate the capacity of 5-HT systems to adapt normally to DMI administration, as manifested by neuroendocrine responsivity to 8-OH DPAT, was compromised in adult animals exposed to nicotine in utero.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed1995

Prenatal stress prevents the desensitization of the corticosterone response to TFMPP by desmethylimipramine, but not by phenelzine, in adult male offspring.

Gravid female rats were subjected to one hour of restraint stress twice daily or left undisturbed from days 14-21 of gestation. Adult 105-day old male non-stressed (NS) and stressed (S) offspring were treated once daily with saline, desipramine (DMI) (10 mg/kg, sc) or phenelzine (5.0 mg/kg, sc) for 14 days. Twenty-four hours after the last injection, animals were challenged with saline or 1-(m-trifluoromethylphenyl)piperazine (TFMPP) (5.0 mg/kg, sc), a serotonin1B/2C (5-HT1B/2C) agonist, and plasma prolactin and corticosterone concentrations were measured one hour later. As compared to acute saline administration, TFMPP significantly increased prolactin and corticosterone concentrations in all groups. In NS offspring, both DMI and phenelzine treatment augmented the prolactin response, but blunted the corticosterone response, to TFMPP. In S offspring, the prolactin response to TFMPP also was augmented by phenelzine or DMI treatment, whereas the corticosterone response to TFMPP was blunted during phenelzine treatment. However, DMI treatment was not able to desensitize the corticosterone response to TFMPP in the S rats. The results indicate the adaptive capacity of 5-HT systems to DMI administration was compromised in adult animals exposed to stress in utero.

Adaptation, Physiological↗
PubMed1994

Exposure to threshold doses of nicotine in utero: II. Neuroendocrine response to nicotine in adult male offspring.

Groups of gravid female rats were injected subcutaneously with saline (SAL), a low-dose of nicotine (LN) (0.05 mg/kg, bid) or a high-dose of nicotine (HN) (3.0 mg/kg, bid) from day 4 to day 20 of gestation, or were left undisturbed. In adult 120-day-old male offspring, the ACTH and prolactin responses to acute nicotine challenge were evaluated. The experiment was performed on three separate occasions. Based upon dose-response and time-course studies with nicotine in normal animals, the neuroendocrine responses to nicotine (0.75 and 1.0 mg/kg, sc) were measured 7.5 min after nicotine administration, the peak response-time for both hormones. The ACTH response to acute nicotine administration was blunted significantly in the HN rats, but normal in the LN rats, for all three experiments. In two experiments, the prolactin response to acute nicotine administration was blunted significantly in the HN rats, but enhanced significantly in the LN offspring. The results indicate that prenatal nicotine administration can produce long-term neuroendocrine effects involving nicotinic-receptor coupled circuits, with long-term functional sequelae produced by dosages of nicotine considerably smaller than previously shown to be pharmacologically/toxicologically active.

Adrenocorticotropic Hormone↗
PubMed1994

[Uterine leiomyoma: pathology and epidemiology].

Two hundred biopsy reports with uterine myoma histopathological diagnosis were studied 67% of the cases were between 41-50 years of age. Premenopausic patients showed an average number of myomas almost three times higher than the postmenopausic women. The most frequent myoma were those within the walls with a size less than 2 cm. Chronic inespecific cervixitis was the most frequent finding in the cervix pathology, with in 1.5% of the cases. In 2 cases (1%) endometrial adenocarcinoma was found. In 60.5% of the cases one or both tubes and ovaries were removed neither case had malignant alterations. In 51 cases (25.2%) the myoma presented some type of degeneration, the most frequent being the cellular type, 16 out of 200, which represented 8% of the cases; it was considered as presarcomatose type. Presurgical clinical behavior is discussed considering the analysis of these figures and the perspectives of the conservative treatment with the use of new no ablative technique.

Adult↗
PubMedDate not supplied

Maternal blood lead level during pregnancy in South Central Los Angeles.

Twenty-five years of public health efforts produced a striking reduction in lead exposure; the blood lead average in the United States has decreased to less than 20% of levels measured in the 1970s. However, poor minority groups that live in large urban centers are still at high risk for elevated lead levels. In this study, our data showed that pregnant immigrants (n = 1,428) who live in South Central Los Angeles--one of the most economically depressed regions of California--have significantly higher (p < .0001) blood lead levels (geometric mean = 2.3 microg/dl [0.11 micromol/l]) than 504 pregnant nonimmigrants (geometric mean = 1.9 microg/dl [0.09 micromol/l]). The most important factors associated with lower blood lead levels in both groups were younger age; more-recent date of blood sampling (i.e., decreasing secular trend); and blood sampling in mid-autumn, instead of mid-spring (i.e., seasonal trend). Blood lead levels of immigrants were strongly dependent on time elapsed since immigration to the United States; each natural log increase in years of residence was associated with an approximately 19% decrease in blood lead levels. Although blood lead means for both groups were almost the same as the estimated national average, 25 of the 30 cases of elevated blood lead (i.e., > or = 10 microg/dl [0.48 micromol/l) occurred in the immigrant group. The odds ratio (95% confidence intervals within parentheses) for having elevated blood lead levels (a) was 9.3 (1.9, 45.8) if the immigrant engaged in pica; (b) was 3.8 (1.4, 10.5) if the immigrant had low dietary calcium intake during pregnancy; and (c) was .65 (.43, .98) for every natural log unit increase of years of residence in the United States. The control of pica and dietary calcium intake may offer a means of reducing lead exposure in immigrants.

Adolescent↗
PubMedDate not supplied

Blood lead level and blood pressure during pregnancy in South Central Los Angeles.

In many studies in which the relationship between blood pressure and blood lead level has been examined, investigators have found significant--but small--associations. There was only one previous report of a significant association of blood lead with blood pressure in pregnant women. We measured blood lead level and sitting blood pressure of 1,627 women in their third trimester of pregnancy. We eliminated subjects with known causes of hypertension. Most women (98.4%) were normotensive. We controlled for body mass index, age, and stress--among other factors--and constructed multiple-regression models of lead association with diastolic and systolic blood pressures. Immigrants (73% of total) had significantly higher blood lead levels and different blood pressures than nonimmigrants, suggesting that analysis be stratified by "immigrant, nonimmigrant" status. Positive relationships between blood lead level and blood pressure were found only for immigrants (p < or = .001). From the 5th to 95th blood-lead percentiles (0.9-6.2 microg/dl) in immigrants, systolic blood pressure increased 2.8 mm Hg, and diastolic blood pressure increased 2.4 mm Hg. Higher prior lead exposure of immigrants (97.7% from Latin countries) than nonimmigrants might explain the differential effect of these low levels of blood lead on blood pressure in nonimmigrants. Perhaps some immigrants are at higher risk than nonimmigrants for lead-associated elevated blood pressure during pregnancy, despite blood lead levels within the currently considered acceptable range.

Adult↗