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Biomedical subjects

S Contreras

Publications and source records attributed to S Contreras.

31 records · Page 2Linked to original sources
PubMed1987

Neuroleptic radioreceptor activity and clinical outcome in schizophrenia.

The relationship between serum haloperidol concentration and clinical response was examined in 27 schizophrenic inpatients between the ages of 18 and 56 years. All patients were treated with haloperidol, 20 mg/day for the first 2 weeks. Dosage adjustment after 2 weeks of treatment was made in seven subjects based on poor clinical response or side effects. Haloperidol activity was determined by the radioreceptor assay for neuroleptics on weeks 2 and 4 serum samples. The results indicated that higher radioreceptor activity levels, particularly above 22 ng/ml, were associated with poorer clinical response. The data suggest that radioreceptor activity levels are not at a steady state after 2 weeks drug treatment. Additionally, problems secondary to low sensitivity of the radioreceptor assay may limit its utility at low serum concentrations.

Adolescent↗
PubMed1984

Biological similarities and differences between rats genetically different in alcohol preference.

This paper is an inventory of some behavioural, biochemical and pharmacological similarities and differences between two inbred strains of Wistar rats differing in voluntary consumption of ethanol, namely: UChA and UChB with low and high preferences respectively for ethanol under conditions involving free choice between a 10% (v/v) ethanol solution and distilled water. The following strain differences were observed: ethanol consumption (UChA less than UChB); total water consumption (UChA less than UChB); solid food consumption (UChA greater than UChB); rate of recovery of ethanol label in expired CO2 (UChA less than UChB); oxidation of ethanol to acetaldehyde by brain homogenates (UChA greater than UChB); acetaldehyde disposal by brain homogenates (UChA less than UChB); ethanol (90 mmol/kg, i.p.) sleeping-time (UChA less than UChB); chronic and acute tolerance to ethanol (UChA developed it, whereas UChB did not); lethal doses of ethanol (UChA greater than UChB); recovery rate of the label of gluconate in expired CO2 (UChA less than UChB); recovery rate of the label of fructose in expired CO2 (UChA less than UChB); blood-glucose level after glucose (1 g/kg, i.p.) load (UChA less than UChB). No strain differences were observed in the rate of recovery in expired CO2 of the label of the following substrates: acetate, pyruvate, butyrate, citrate, ribose, glycerol, sorbitol, glucose and galactose.

Alcoholic Intoxication↗
PubMedDate not supplied

Effects of pyrazole on the voluntary consumption of ethanol, water and solid food in UChA and UChB rats.

The effect of pyrazole (35 or 70 mg/kg IP) on the voluntary consumption of ethanol, water and solid food was studied in UChA (genetically low ethanol consumer) and UChB (genetically high ethanol consumer) rats of both sexes, under a free choice of 10% v/v ethanol solution, distilled water and solid food. the data were analyzed according to the method previously proposed for recognizing the specific effect on appetite-satiety of ethanol. The effect of pyrazole in UChB rats correlated with the pattern of specific effects on appetite-satiety for ethanol. The only effect observed in UChA rats was a decrease in the intake of solid food and total water. No significant sex differences were observed.

Alcohol Drinking↗
PubMedDate not supplied

A method for recognizing specific effects on ethanol intake by experimental animals.

A method of mathematical treatment of data concerning changes in voluntary consumption of ethanol solution, water and solid food, induced by experimental treatments in animals, in order to recognize effects on mechanisms involved in specific appetite and satiety for calories, water and ethanol is proposed. The need of such method arises from the fact that several experimental treatments tested by the effects on ethanol consumption alter at the same time the appetite or satiety for calories and/or for water, as well as ingestive behavior. The results of testing the method with the data obtained by treatment of UChA and UChB rats with disulfiram or cyanamide were consistent with the expected ones.

Alcohol Drinking↗
PubMedDate not supplied

Effects of p-chlorophenylalanine on the voluntary consumption of ethanol, water and solid food by UChA and UChB rats.

The immediate and the long-lasting effects of PCPA (126 mg/kg IP for 3 days) on the voluntary consumption of 10% v/v ethanol solution, water and solid food were studied in genetically low (UChA) and high (UChB) ethanol consumer rats. Data were analysed according to the method proposed by the authors for recognizing specific effects on ethanol consumption. Results confirmed immediate specific decrease of ethanol consumption in UChB rats, while a nonspecific decrease of it was observed in UChA rats. In UChB rats ethanol consumption recovered the basic level about nine days after the first dose. By contradistincion, in UChA rats a significant specific increase of ethanol consumption, starting at the first week after the treatment, was observed. During this period 12 out of 21 UChA rats reached an ethanol consumption level commonly observed in UChB rats, and 10 of them recovered the pretreatment level in 15 to 30 weeks. The other 2 maintained the high consumption until 38 weeks of observation. At that time the serotonin content of cortex and hippocampus of these 2 rats was normal.

Alcohol Drinking↗
PubMedDate not supplied

Effects of serotonin uptake blockers and of 5-hydroxytryptophan on the voluntary consumption of ethanol, water and solid food by UChA and UChB rats.

The effects of zimelidine, fluvoxamine, and citalopram (serotonin uptake blockers), as well as those of 5-hydroxytryptophan (serotonin precursor), on the voluntary consumption of 10% ethanol solution, distilled water and solid food were tested in UChA (genetically low ethanol consumer) and UChB (genetically high ethanol consumer) rats. Since it is well known that drugs which stimulate central serotonergic synapses decrease food and water intake, the data concerning the difference of the respective consumption during the treatment period and the pretreatment one were analysed with a method previously proposed (Alcohol 5:15-19; 1988) to recognize specific effects on ethanol intake. The results showed that while the decrease of ethanol consumption induced by the three serotonin uptake blockers appeared not to be specific of ethanol, the effects of 5-hydroxytryptophan in UChB rats satisfy the criteria for being considered as an expression of a decrease of the specific appetite--or increase satiety--for ethanol. Experimental results cannot help in the explanation of this difference.

5-Hydroxytryptophan↗
PubMedDate not supplied

Electroencephalographic effects of flucloxacillin in rats.

The neurotoxicity of flucloxacillin, an isoxazolyl derivative of beta-lactamic antibiotics, was studied in rats by electroencephalographic recordings. The results show that intravenous flucloxacillin, (200 mg/kg) produced cortical activity modifications. The changes in electroencephalogram consist of irritative activity patterns and bursts of high voltage waves with spikes and polyspikes. The effects of other beta-lactamic drugs (cloxacillin, ampicillin-sulbactam and penicillin G) on electroencephalography activity were also investigated after intravenous administration of equivalent doses. These drugs did not change the normal bioelectric cerebral activity of the rats.

Ampicillin↗
PubMedDate not supplied

[Congenital Chagas-Mazza disease in Salta, Argentina].

A study was carried out on T. cruzi infection in pregnant women in the Guemes area in Salta province; the rate of infection was 12.3%. Of newborn children studied by the microhematocrit technique, 8.8% were diagnosed with Chagas' disease. All of them were treated with benznidazol (5mg/kg/day) for one month; all of them presented anemia, which was interpreted to be an adverse drug reaction. The microhematocrit technique is believed to represent the best option for diagnosis of this disease in newborn children. A diagnostic methodology to follow the course of the infection is proposed.

Argentina↗
PubMedDate not supplied

Restoration of proximal contact in direct class II resin composites.

Although this technique performed well in the case presented, it becomes more advantageous with larger restorations. This would be especially true for core build-up restorations of missing cusps, although such cusps must be restored prior to placement of separating rings. Clear plastic matrices are available and permit effective curing of resins, but the authors find the preset contours of these matrices not sufficiently adaptable to differing clinical situations and prefer metal matrices, even though these necessitate additional light curing after matrix removal.

Composite Resins↗