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Biomedical subjects

R Paredes

Publications and source records attributed to R Paredes.

At least 19 recordsLinked to original sources
PubMed1992

[Association between post-initial remission and HLA phenotype in Type I diabetics].

Our goal was to estimate the occurrence rate of the post-initial remission and its relation with HLA phenotype in type I diabetics (DMI). We studied 50 type I diabetics, 22 women and 28 men, with an average age at the onset of the disease to 15.8 +/- years (range 3-30 years). All patients were conventionally treated with insulin therapy, diet and regular exercise. Six (12%) of the diabetics presented a complete remission during 57.3 +/- 46 weeks, whereas fifteen (30%) patients presented partial remission during 20.1 +/- weeks. No significant differences were observed with regard to age at the onset of the disease, sex, BMI, initial ketoacidosis and stage of gonadal development between those diabetics presenting remission and those who did not presented so. We observed a higher incidence of the HLA-DR4 antigen among diabetics with remission (complete and partial, 61.9%), compared with patients without remission (20%, p less than 0.5). In conclusion, our results support the findings suggesting the presence of a clinical-immunological heterogenicity in DMI, genetically determined and linked to the HLA system.

Adolescent↗
PubMed1991

Sexual behavior and copulatory thrusting patterns in male rabbits treated with GABA transaminase inhibitors.

The effects of enhanced central nervous system GABA levels on sexual behavior and copulatory pelvic thrusting were evaluated in male New Zealand white rabbits. The GABA transaminase inhibitors sodium valproate and gamma-acetylen GABA (GAG), in doses of 100 and 200 mg/kg and 50 and 100 mg/kg, respectively, were intraperitoneally administered and sexual behavior recorded at several intervals after drug administration. At the same time, copulatory thrusting was registered using a polygraphic technique. Tests for gross motor functions were also performed. None of the drugs had any effect in these latter tests. Sodium valproate, in a dose of 100 mg/kg, had a slight inhibitory effect on sexual behavior at 280 min postinjection. A dose of 200 mg/kg inhibited sexual activity already 15 min postinjection, and the effect lasted for at least 280 min. GAG, 100 mg/k, inhibited mounting behavior at 8 h postinjection, and ejaculation was reduced from 2 to at least 8 h postinjection. Copulatory thrusting patterns were not affected by the drug treatments. These data suggest that increased GABAergic activity reduces sexual arousal in the rabbit. GABA does not seem to be critically involved in the regulation of the motor patterns underlying pelvic thrusting. There are important quantitative and qualitative differences between rats and rabbits with regard to the actions of GABA transaminase inhibitors upon sexual functions.

4-Aminobutyrate Transaminase↗
PubMed1990

Medial preoptic area kindling induces sexual behavior in sexually inactive male rats.

In the present experiments, sexually experienced and non-copulating male rats were kindled in the medial preoptic area (MPOA) or the amygdala (AMG) with the purpose to investigate if the widespread modification of brain function produced by kindling induces sexual behavior in non-copulating rats and if kindling facilitates sexual behavior in copulating rats. Since kindling in the MPOA has been little studied, a description of this phenomenon is also presented. The animals were stimulated 4 times daily on odd days and sexual behavior monitored on even days. The results showed that the MPOA required higher stimulus intensity to elicit an afterdischarge (AD) than the AMG. The AD duration was significantly longer in animals kindled in the MPOA than in animals kindled in the AMG. No difference was found in the development of kindling between these brain structures. Kindling had no effect upon sexual behavior in copulating rats. In contrast, MPOA kindling induced copulation in non-copulating male rats. Seven out of 9 animals displayed sexual behavior. No significant facilitation was observed after AMG kindling in non-copulating male rats. Furthermore, the sexual behavior displayed by the previously non-copulating MPOA kindled rats was similar to the sexual behavior displayed by sexually experienced animals. It is proposed that sexual behavior is facilitated in these male rats by local neural changes produced by kindling.

Animals↗
PubMed1990

[Tuberculosis in kidney transplant patients].

We studied the incidence of tuberculosis in 37 renal transplant patients. Mean age was 37 years and immune suppression therapy had been used for a mean of 37 months. Tuberculosis-free cases had received prednisone at a mean dose of 10 +/- 4 mg/day and azathioprine, 96 +/- 35 mg/day. 28% of patients had a positive tuberculin test, 24% a healed tuberculous lung lesion and 40% received chemoprophylaxis. Four patients developed tuberculosis, 10 times the incidence expected for the general population. Fever was present in all patients. Two patients had a disseminated form and one a laryngeal location. None of the patients had received chemoprophylaxis and the dose of prednisone was higher (18 +/- 9 mg/day) than that received by non-infected patients. Thus, chemoprophylaxis for tuberculosis appears warranted in all renal transplant recipients, regardless of tuberculin test results or chest X ray findings.

Adult↗
PubMed1989

Stereospecific actions of baclofen on sociosexual behavior, locomotor activity and motor execution.

The behavior effects of racemic baclofen and the R and S enantiomers were studied in order to determine whether the stereospecificity found in receptor binding studies also applies to the behavioral actions of the drug. Racemic and R-baclofen inhibited sexual behavior, locomotor activity and motor execution at relatively low doses while s-baclofen was completely inactive even when a dose 40 times higher than the minimum effective dose of R-baclofen was used. The R enantiomer seems to be twice as active as racemic baclofen. These data strongly suggest that the behavioral effects of baclofen are the result of an action at the GABA-B receptor. In order to differentiate the effects of baclofen on sexual interactions from those on nonspecific social interactions, the sociosexual behavior was observed with a castrated male or a receptive female as stimulus animal. R, S-baclofen had effects only upon sociosexual interaction with a receptive female. Moreover, the inhibitory effects of baclofen were restricted to behavioral items related to sexual interactions, primarily those constituting precopulatory behaviors. Since no effect was observed in social interactions with a castrated male, it is suggested that the inhibition of sociosexual behavior is not a consequence of impairment of motor execution. Rather it appears that baclofen has a specific inhibitory effect on behaviors associated with the initiation of copulatory activity. Therefore, once initiated, sexual behavior was not significantly modified by baclofen.

Animals↗
PubMed1989

GABAergic drugs and lordosis behavior in the female rat.

Agents modifying GABAergic neurotransmission were administered to ovariectomized rats treated with different doses of estradiol benzoate (EB) + progesterone (P) or with EB alone. Hormone treatments were designed to induce an intermediate level of receptivity in order to be able to observe both stimulatory and inhibitory effects on lordosis behavior. Both the GABAA receptor agonist THIP and the GABAB receptor agonist baclofen inhibited lordosis behavior at doses from 20 and 5 mg/kg, respectively. The GABA transaminase inhibitor gamma-acetylen GABA (GAG) and the GABA agonist 3-aminopropanesulfonic acid had no effects, even when high doses were administered. The GABAA receptor antagonist bicuculline had no effect by itself nor did it block the effects of THIP. It is therefore suggested that the GABAA receptor is of slight importance in the control of lordosis behavior. No evidence could be found supporting the hypothesis that an interaction between P and GABA is important for hormone-induced receptivity. It does not appear likely that motor disturbances are responsible for the inhibitory effects of baclofen and THIP. The exact mechanism by which these drugs inhibit lordosis behavior is not clear at present.

Alkynes↗
PubMed1989

[Adenosine deaminase activity in peritoneal tuberculosis].

We performed a prospective study including cytochemical, bacteriologic and pathologic observations in 25 patients with ascites of different causes. Activity of adenosine deaminase in ascitic fluid was higher in tuberculous (103 +/- 61 mu/l) than in neoplastic (16 +/- 8), inflammatory (16 +/- 13) and portal hypertension (15 +/- 6) etiologies (p less than 0.05). Inflammatory cases included patients with lupus and spontaneous peritonitis. Activity of adenosine deaminase was higher in every patient with tuberculosis than in any other patient. Thus, a high sensitivity and specificity of this test in the diagnosis of tuberculous peritonitis is confirmed.

Adenosine Deaminase↗
PubMed1988

Opioids and sexual behavior in the male rat.

Naloxone in the doses of 4 or 16 mg/kg failed to affect copulatory behavior of testosterone-treated castrated male rats. Morphine 10 mg/kg, administered 60 min before behavioral observation, reduced the proportion of animals displaying sexual behavior. Doses of 2.5 or 5 mg/kg reduced the latency to the second ejaculation, whereas the few animals still copulating after morphine 10 mg/kg showed a reduced latency to the first ejaculation. The same doses of morphine administered 5 min before behavioral observation produced a dose-dependent reduction of mount, intromission and ejaculation percentages. However, those animals that did copulate showed a normal copulatory behavior. D-Ala2-Met5 enkephalinamide (DALA) infused into the left cerebral ventricle in a dose of 5 micrograms 5 or 60 min before tests had no effect. When the peptide was infused 30 sec after the first intromission, the number of intromissions as well as the latency to ejaculation were reduced. Opioids may facilitate ejaculatory mechanisms, perhaps as a consequence of their rewarding properties. Moreover, in animals treated with DALA after the first intromission, the number of intromissions and the latency to ejaculation were similar for the first and second copulatory series, while these parameters were much reduced upon the second ejaculation for control animals. It is possible that liberation of endogenous opioids is the cause of ejaculation-induced facilitation of subsequent sexual behavior.

Animals↗
PubMed1987

Citizen participation in police crisis intervention activities.

A naturalistic experiment tested the proposition that police time could be saved in nondangerous crisis intervention calls through the use of citizen participants. Results showed that police officers who used citizen intervention spent less time per call than officers who did not. However, police time was not saved in family disturbance calls. Family disturbance control group calls were rated by police as having a higher degree of physical danger present than other calls.

Adult↗
PubMed1987

Differential effects of GABA transaminase inhibitors on sexual behavior, locomotor activity, and motor execution in the male rat.

The GABA transaminase inhibitors gamma-acetylen GABA (GAG) and sodium valproate were administered intraperitoneally and their effects on locomotor activity, motor execution and sexual behavior were analyzed. It was found that sodium valproate, administered 15 min before observation, reduced locomotor activity only at a dose of 200 mg/kg. Doses of 100 and 400 mg/kg had no effect. Motor execution was impaired in a dose-dependent way, the lowest effective dose being 200 mg/kg. Sexual behavior was also dose-dependently reduced. Sodium valproate, administered 60 min before observation, inhibited all behaviors. The lowest effective dose was 200 mg/kg for locomotor activity and 400 mg/kg for motor execution and sexual behavior. GAG also inhibited all behavior, in doses ranging from 25 mg/kg (locomotor activity) to 100 mg/kg (motor execution and sexual behavior). The data showed that there is no relation between effects on locomotor activity and the effects on sexual behavior, whereas sexual behavior is inhibited whenever motor execution is impaired. Moreover, there is no correlation between effects on locomotor activity and motor execution. It is suggested that GABA transaminase inhibitors effect sexual behavior only indirectly, via an impairment of motor execution. Therefore it is doubtful whether GABAergic mechanisms play any role in the normal regulation of sexual behavior.

4-Aminobutyrate Transaminase↗
PubMed1985

GABAergic drugs and sexual behaviour in the male rat.

The GABAA agonists 3-amino-1-propanesulfonic acid and THIP reduced sexual behaviour in male rats only at relatively high doses, whereas baclofen produced an almost complete inhibition at a low dose (2.5 mg/kg). The GABA transaminase inhibitor aminooxyacetic acid had no effects, while gamma-acetylenic GABA produced a slight inhibition of sexual behaviour. The GABAA antagonist bicuculline had no effect. When THIP was administered concurrently with bicuculline, the former drug was potentiated. Therefore it is concluded that the GABAA receptor is not responsible for the inhibitory actions of THIP, and since baclofen was the most potent drug with regard to effects on sexual behaviour, it is suggested that the GABAB rather than the GABAA receptor is involved in the control of that behaviour. The slight effects of the transaminase inhibitors and the lack of effect of bicuculline suggest that the GABAergic neurons participating in the control of sexual activity are not tonically active. Finally, data are presented showing that the effects of GABAergic drugs on sexual behaviour are probably independent from those on locomotor activity.

4-Aminobutyrate Transaminase↗