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S Mora

Publications and source records attributed to S Mora.

At least 91 records · Page 5Linked to original sources
PubMed1991

Effects of estradiol replacement in ovariectomized rats on conditioned avoidance responses and other behaviors.

The acquisition of conditioned avoidance responses along with spontaneous behaviors were studied in ovariectomized rats. Fourteen days after ovariectomy, they were injected subcutaneously with one of the following doses of estradiol benzoate: 0.2, 2 or 20 microgram/rat. Behavioral tests were applied 3, 24, 48 or 72 hours after estradiol treatment. Although estradiol 2 microgram/rat induced a decrease in acquisition of conditioned avoidance responses at all times tested, this effect was maximum at 48 h. Estradiol 0.2, and 20 microgram/kg decreased and stimulated, respectively, the acquisition performance, as tested 3 h after injection. All doses increased global motility and rearing behavior. This hypermotility disappeared at 24 h, but it was observed again at 48 and 72 h after estradiol 0.2 and 20 microgram/rat. The hormone also induced an increase in head shaking and a decrease in grooming. Although the behavioral changes are more significant in presence of very low serum levels of estradiol, they seem to be triggered by the previous increase in the estradiol levels. The possible sites and mechanisms of action of estradiol on behavior are discussed.

Animals↗
PubMed1991

Behavioral effects of intracerebral administration of luteinizing hormone releasing hormone (LHRH) in rats.

The effects of LHRH intracerebrally infused on acquisition of conditioned avoidance responses (CARs) and spontaneous motility were studied in adult male rats. The results were the following: 1) LHRH (1 and 2.5 micrograms/rat) administered through a cannula stereotaxically implanted into the lateral ventricle induced an impairment in the acquisition of CARs along with an increase in global motility, rearing, head shaking and grooming behavior; 2) LHRH 1 microgram/rat injected into the hippocampus or nucleus accumbens induced also an impairment in acquisition which is evident 15 min after treatment. In contrast, intrastriatal injection induced an immediate disruption of this behavior; and 3) there is a good dose-response relationship for intrastriatal LHRH between 7.8 and 62.5 ng/rat. The results suggest that the estriatum could be the locus of the LHRH-induced inhibition of CARs. Then the possibility of an involvement of the dopamine nigrostriatal system is discussed.

Animals↗
PubMed1990

Bone mass in young patients with type I diabetes.

We measured bone mineral content (BMC) with single photon absorptiometry in two groups of young patients with type I diabetes: the first group (prospective study) consists of 48 patients followed from onset to the third year of diabetes and the second group (cross-sectional study) consists of 66 long-term diabetics. Bone mineral content at onset of disease was lower than normal in only two cases. After 3 years of diabetes no male revealed BMC below the normal range but two females (6.6%) had low BMC values. In our cross-sectional study we found a BMC reduction in 12% of the cases. We did not find a relationship between bone deficit and duration of diabetes, or bone mass values and HbA1.

Adolescent↗
PubMed1989

Influence of the estrous cycle, ovariectomy and estradiol replacement upon the acquisition of conditioned avoidance responses in rats.

The changes in the acquisition of conditioned avoidance responses (CARs) and the performance of some spontaneous behaviors were examined across the estrous cycle of female rats. CARs were facilitated during diestrus, impaired at proestrus and practically abolished at estrus and metestrus. Motor activity and head shaking were minimally affected with the stages of the cycle. Motor activity was increased at metestrus and head shaking decreased at estrus. At 14 days following ovariectomy, there was a significant enhancement of CARs which was antagonized by the daily administration of estradiol benzoate (10 micrograms/kg) for three days. Ovariectomy also increased grooming behavior and estradiol replacement returned grooming to its basal level. The results suggest an inhibitory control of estradiol on CARs and grooming. The involvement of other hormones which also varied across the estrous cycle and its interaction with brain catecholamine systems, particularly dopamine, are discussed.

Animals↗
PubMed1989

Clinical investigations of medetomidine in dogs.

Experiments with 3 doses of medetomidine (20, 40 and 80 micrograms/kg, iv. and im., respectively) were carried out on 90 dogs of 16 breeds in the Small Animal Surgery of the University of Veterinary Science, Budapest. Changes in hematology as well as in AST, AP, BUN, creatinine were studied. Medetomidine administered iv deepened the sedation and lengthened tranquillization dose-dependently. After im administration the sedative effect was still dose-dependent, but the duration of its clinical effectiveness could not be lengthened significantly. The development of the sedation could however, be quickened. The iv administration increased the level of analgesia in proportion to dosage; the im application could change the level of pain-killing effect of the drug, but could not lengthen it. According to the laboratorical determinations, regardless of the dosage and the route of application, medetomidine did not affect the AST and AP enzyme activities, or the BUN and creatinine values.

Adrenergic alpha-Agonists↗
PubMed1988

LHRH antagonizes yawning and genital grooming induced by apomorphine in rats.

The effects of the pretreatment with LHRH on the behavioral effects induced by low doses of apomorphine were studied in male rats. Three doses of apomorphine (31.25, 62.50 and 125 micrograms/kg) were subcutaneously administered two hours after LHRH 100 micrograms/kg or solvent SC treatment. Apomorphine induced repeated episodes of yawning and genital grooming. Pretreatment with LHRH abolished or reduced yawning and genital grooming induced by the three doses of apomorphine, suggesting that the peptide could induce subsensitivity of DA receptors responsible for yawning and genital grooming.

Animals↗
PubMed1988

Effects of pretreatment with luteinizing hormone releasing hormone (LHRH) on behaviors induced by apomorphine in rats.

The influence of LHRH on the behavioral effects induced by apomorphine (APO) was studied in male rats. Several doses of apomorphine (31.25, 62.5, 125, 250 and 500 micrograms/kg) were administered subcutaneously (SC) after LHRH 100 micrograms/kg or solvent. Low doses of apomorphine induced hypomotility and impaired acquisition of a conditioned avoidance response (CAR). High doses produced hypermotility, stereotyped sniffing and a short lasting increase, followed by a decrease in the acquisition of CARs. Pretreatment with LHRH potentiated the hypomotility induced by low doses of apomorphine (62.5 and 125 micrograms/kg) and the hypermotility, stereotyped sniffing and the enhancement in acquisition of CARs produced by higher doses of apomorphine (250 and 500 micrograms/kg). These findings suggest that LHRH could indirectly regulate dopamine activity through an increase in sensitivity of dopamine receptors (pre- and postsynaptic), which mediate the behavioral effects of APO. It is postulated that this hypersensitivity of DA receptors could be the consequence of an inhibition of presynaptic dopaminergic transmission, induced by LHRH.

Animals↗
PubMed1986

Pharmacological evidence of catecholaminergic involvement in the behavioral effects of luteinizing hormone releasing hormone in rats.

The influence of L-DOPA on the behavioral effects of LHRH was studied in male rats. Subcutaneous administration of LHRH (100 micrograms/kg) caused a significant disruption in the acquisition of a conditioned avoidance response (CAR) and a significant increase in head shaking behavior (HSB). Pretreatment with this hormone antagonized the stimulatory action of amphetamine (1 mg/kg, IP) in acquisition of CARs, spontaneous motor activity (SMA) and rearing behavior (RB). L-DOPA (100 mg/kg, IP), administered after LHRH, stimulated SMA, RB and HSB. In addition L-DOPA antagonized the effect of LHRH on acquisition of CARs and counteracted the antagonism between LHRH and amphetamine in acquisition of CARs and SMA. These findings indicate that LHRH could exert its behavioral effects through an inhibitory action upon brain catecholamine synthesis. The suppression of CARs may be the response to DA antagonism and the interaction with amphetamine could be mediated by an inhibition of both DA and NE activities. The possibility of an interaction between LHRH and central serotonin mechanisms is also discussed.

Amphetamine↗
PubMed1985

Luteinizing-hormone-releasing hormone modifies retention of passive and active avoidance responses in rats.

The influence of posttraining subcutaneous administration of luteinizing-hormone-releasing hormone (LHRH) was tested on the retention of either active or passive avoidance conditioning in male rats. Injection of LHRH (200 micrograms/kg) immediately after the acquisition of an active avoidance response (two-way shuttle behavior) enhanced retention of the response, assessed 7 days later. When the neuropeptide was injected immediately after a passive avoidance conditioning training, the effects varied with the intensity of the footshock applied. LHRH enhanced retention of avoidance training with weak footshock (0.20 and 0.35 mA) but impaired retention of training with strong footshock (0.70 and 1.0 mA). The effects of LHRH seem to be unspecific since they are similar to those observed after treatment with several hormones. The results are discussed based on the interactions between peripherally injected hormones and endogenous substances released following footshock. A modulatory effect on the monoaminergic pathway involved in memory storage processes is postulated.

Animals↗
PubMed1983

LHRH and rat avoidance behavior: influence of castration and testosterone.

Pretraining subcutaneous administration of a high dose of LHRH (100 micrograms/kg) to intact rats impaired acquisition of a conditioned avoidance response (CAR) in a two way shuttle box. Acquisition of a CAR was also decreased when LHRH was administered to castrated rats. LHRH antagonized the dose related impairment in acquisition and retention performance induced by testosterone in castrated animals. The results are discussed based on the interrelationships between castration, testosterone, LHRH and brain monoamines.

Animals↗
PubMed1983

Influence of luteinizing hormone releasing hormone (LHRH) on the behavioral effects of amphetamine in rats.

The influence of luteinizing hormone releasing hormone (LHRH) on the behavioral effects induced by several doses of D-amphetamine (0.25, 0.5, 1.0 and 2.0 mg/kg IP) was studied. A dose response relation was previously established for the effects of LHRH (50, 100 and 200 micrograms/kg SC) on acquisition and retention of conditioned avoidance responses (CARs). The neuropeptide impaired acquisition and improved retention of CARs, without modifying spontaneous motor activity. Pretreatment with 100 micrograms/kg of LHRH antagonizes the enhancement in acquisition of CARs due to D-amphetamine 0.5, 1.0 and 2.0 mg/kg, the impairment in retention induced by amphetamine 1.0 and 2.0 mg/kg, and the hypermotility and the increased rearing behavior induced by amphetamine 1.0 and 2.0 mg/kg. These results suggest that brain catecholamines, particularly dopamine, could play a role in the behavioral effects of LHRH. Interactions between LHRH and central dopaminergic mechanisms are discussed.

Animals↗
PubMed1980

TRH on rat conditioned avoidance behavior: interaction with brain catecholamines.

TRH (10 micrograms) intracerebroventricularly injected improves the acquisition of a two-day avoidance conditioning. This effect is partially antagonized by pretreatment IP with alpha-methyltyrosine (60 mg/kg) or disulfiram (300 mg/kg). L-DOPA (100 mg/kg) administered IP 2 hr after alpha-MT partially restores the facilitatory effect of the hormone. The possible roles of brain catecholamines on the behavioral effect of TRH are analysed. Other tentative mechanisms of action are also discussed.

Animals↗
PubMedDate not supplied

Effect of oxotremorine on the acquisition of a conditioned avoidance response is modified by the estrous cycle, ovariectomy, and estradiol replacement in rats.

This study was designed to evaluate the influence of the hormonal status of the rat on the effects of a potent reversible muscarinic agonist, oxotremorine, on the acquisition of conditioning avoidance responses (CARs) and the performance of some spontaneous motor behaviors. Oxotremorine (OXO 50 and 100 micrograms/kg, intraperitoneally) given 5 min before testing improved active conditioned avoidance in intact female rats at estrus and in ovariectomized rats after estradiol replacement, and impaired performance in female rats at diestrus and after ovariectomy without estradiol replacement. No significant differences due to hormonal status of the rat in some spontaneous motor behaviors were observed. In fact, OXO in this dose range failed to induce significant changes in spontaneous motor activity, the number of rears diminished, and the time spent in grooming behavior increased in all groups studied. These results provided behavioral evidence for the hypothesis that central cholinergic activity is function of the hormonal status of the animal. Relationships between ovarian hormones and cholinergic system are discussed.

Animals↗
PubMedDate not supplied

[Antibodies against hepatitis C virus. Study in voluntary blood donors. Cuba 1991].

Four hundred and sixty one samples randomly selected among blood donors from three blood banks in Havana City were investigated for HCV antibodies. Samples repeatedly reactive to Organcon Tecknica immunoenzymatic assay were considered positives and were further confirmed by an Ortho test. An epidemiological survey was conducted among all donors included in the sample to assess infection risk factors. Seven subjects (1.5%) resulted repeatedly reactive to the test, slightly higher than in developed countries. Mean age in positive patients was seven years higher than in negative subjects (39 vs 31.5), but the Student's test did not show any significant difference. Seropositivity was higher in males (1.7 vs 0.9) and very similar as to the color of skin (1.9 mulattos, 1.5 whites and 1.0 blacks) but it was not statistically significant (p > 0.05). Among risk factors with higher odd ratios were to have more than five sexual partners in the last five years and having worked in a health care institution, but this was not statistically significant (p > 0.05). The probability of receiving one unit of HCV infected blood was of 1.5% and 45% when receiving 40 units. Given the importance of the virus, the need of establishing specific control measures in the shortest period of time for HCV detection in blood is under-lined.

Adult↗
PubMedDate not supplied

[I131 in blood samples: management in the laboratory].

OBJECTIVES: Patients treated by (131)I may require blood sampling in the days following its administration. We investigated the safety of such samples in terms of radioactivity and the possible disturbance of the analyses by these "131I-spiked" samples. METHOD: 1) The radioactivity of blood samples from 131I-treated patients was measured (dose rate, surface activity, total activity) ; 2) The risk for the personnel was subsequently evaluated and ; 3) The interference of this 131I-generated radioactivity on the results of routine automated and IRMA assays was investigated. RESULTS: 1) All RA measures but two were found below the European limits ; 2) Irradiation of personnel was negligible ; 3) The faint radioactivity did not disturb any analyses. CONCLUSION: These data demonstrate the safety that results from the negligible radioactivity in these blood samples.

Drug Contamination↗