Biomedical subjects

L Palacios

Publications and source records attributed to L Palacios.

59 records · Page 4Linked to original sources

PubMedDate not supplied

Multiple inert gas elimination technique for determining ventilation/perfusion distributions in rat during normoxia, hypoxia and hyperoxia.

1. The use of the multiple inert gas elimination technique (MIGET) in quantifying ventilation/perfusion distributions (V*A/Q*) in small animals, such as the rat, may cause results to be biased due to haemodilution produced by the large volume of liquid infused intravenously. 2. We tested two methods of administering inert gases in rats using the MIGET: (i) standard continuous intravenous administration of inert gases (method A); and (ii) a new method based on the physicochemical properties of each inert gas (method B). This method included acute simultaneous inert gas administration using three pathways: inhalation, intravenous infusion and rectal infusion. Both MIGET methods were applied to obtain data while breathing three different inspiratory fractions of oxygen (FIO2): normoxia, hypoxia and hyperoxia. 3. Inert gas levels obtained from blood or expired air samples were sufficient for chromatographic measurement, at least during a 2 h period. The V*A/Q* distributions reported using both methods were acceptable for all the physiological conditions studied; therefore, the alternative method used here may be useful in further MIGET studies in rats because haemodilution resulting from continuous intravenous infusion of less-soluble gases can be avoided. 4. Normoxic rats showed lower mean values of the V*A/Q* ratio of ventilation distribution and higher mean values of the V*A/Q* ratio of perfusion distribution with the usual method of inert gas administration (method A). These non-significant differences were observed under almost all physiological conditions studied and they could be caused by haemodilution. Nevertheless, the effect of interindividual differences cannot be discarded. An additional effect of the low haematocrit on cardiovascular changes due to low FIO2, such as pulmonary vasoconstriction or increased cardiac output, may explain the lower dispersion of perfusion distributions found in group A during hypoxia.

Animals↗

PubMedDate not supplied

Effect of temperature on oxygen stores during aerobic diving in the freshwater turtle Mauremys caspica leprosa.

Oxygen stores available for aerobic diving were studied in the freshwater turtle (Mauremys caspica leprosa) at three constant body temperatures (15 degrees, 25 degrees, and 35 degrees C) and during the thermal transient (30 degrees-15 degrees C) induced by immersion in cold water. The term "aerobic dive limit" has been defined as the maximal duration of the dive before lactate increases. This increase occurs when a critical PO2 value is reached, and it is well characterized at lung level by a sharp increase in the lung apnoeic respiratory quotient. Kinetic analysis of lung gas composition during forced dives at fixed body temperature shows that critical PO2 values rise with temperature and that the postventilatory PO2 at the beginning of a dive decreases, so that the two temperature-dependent factors lead to a significant decrease with temperature in the lung O2 stores available for aerobic diving. During dives with transient body cooling, a natural condition in M. caspica leprosa, temperature equilibration occurs fast enough to expand aerobic scope by bearing the critical PO2 to the same value obtained at a fixed temperature of 15 degrees C. These dives are characterized by reversed CO2 transport (from lung to tissues) and therefore by negative values of the lung respiratory quotient; a decrease in temperature increases CO2 capacitance of tissues, resulting in a fall in PCO2 at constant CO2 content. Because this does not occur in the gas phase, PCO2 difference can lead to diffusion in the direction opposite from normal. This pattern may favour lung-to-tissue O2 transfer, through the Bohr effect. Therefore, the aerobic dive limit is reduced at high temperature not only through a metabolic rate effect but also through a marked decrease in the available O2 stores; fast body cooling (30 degrees-15 degrees C) associated with immersion in cold water extends the O2 stores available for aerobic diving to a level similar to that of immersions at constant body temperatures that are in equilibrium with water temperature.

Animals↗

PubMedDate not supplied

Lamotrigine in treatment of 120 children with epilepsy.

One hundred twenty children aged 10 months to 16 years 9 months were included in three studies with lamotrigine (LTG): a single-blind study (n = 60), a pharmacokinetic study (n = 23), and a compassionate group (n = 37). At 3 months, 11 patients had become seizure-free and 34 had > 50% decrease in seizure frequency. The best results involved absence epilepsy, Lennox-Gastaut syndrome (LGS), and other symptomatic generalized epilepsy. Forty-two patients were followed > 1 year, 22 for a mean of 2.2 years, and there was no significant increase in seizure frequency as compared with 3-month follow-up. Fourteen patients became seizure-free for > 6 months; all except 1 had generalized epilepsy. For 12 patients, treatment could be reduced to monotherapy, but for those with valproate (VPA) comedication LTG dosage had to be increased; 25% of patients with VPA monotherapy exhibited skin rash, appearing 3-18 days after starting LTG. For 4 patients, LTG could be reintroduced after VPA was withdrawn. Ten patients had ataxia and/or drowsiness and 2 had vomiting. For all other patients, tolerance was excellent.

Adolescent↗

PubMedDate not supplied

[Validity and reliability of the Spanish version of Yale-Brown obsessive-compulsive rating scale for children and adolescents].

INTRODUCTION: The Children Yale-Brown Obsessive- Compulsive Scale (CY-BOCS) constitutes a very good instrument for the evaluation of obsessive-compulsive disorder (OCD) symptoms, by a clinical interview administered to the patient and parent, that includes summary score of the clinician. OBJECTIVE: We are proposing a Spanish version of instrument, which is rated during a brief clinical interview to the parents and the patients. We are presenting data reliability and validity using two out-patient samples. METHODS: After the translation to Spanish, a back translation and adaptation to Spanish of the CY-BOCS, twenty eight out-patients (75 % male) with a mean age 12.1 (+/- 2.7) from two clinical settings on Mexico City evaluated. Reliability was evaluated by computing the internal consistency (Cronbach's alpha) on all interviews. assess interrater agreement, the interviews were videotaped and scored by three independent raters and all of them included both the child and the parent interview. The CY-BOCS total scored was correlated with the K-SADS-PL diagnosis. RESULTS: The CY-BOCS total score for all subjects was 16.5 +/- 9.8. Cronbach's alpha coefficient was 0.87; Pearson correlation of total CY-BOCS score with the K-SADS-PL diagnosis was 0.60 (p < or = 0.05). The intraclass correlations coefficients for the parents, youngsters and clinician 0.96, 0.94 and 0.92, respectively. CONCLUSIONS: The Spanish version of the CY-BOCS reliable and valid instrument, useful for both clinicians and researchers in child and adolescent OCD assessment.

Adolescent↗

PubMedDate not supplied

[Iron nutrition in Mapuche infants fed with human milk (2d phase)].

Blood hemoglobin, serum iron, total iron binding capacity (TIBC) and serum ferritin were measured in 140 healthy rural mapuche (southern Chile's indigenous ethnic group) infants aged 8 to 15 months: 90 had been exclusively breast fed for the first 5 or 6 months of life, then solid foods were introduced but cow's milk was never given to them. The remaining 50, which were all weaned at nearly 4 months of age and then given cow's milk and solid foods at the corresponding age, were designated as controls. Anemia was detected in 4.5% of breast fed infants and in 38% of controls. Evidence of iron deficient erythropoiesis was found in 5% and 81% of cases and controls, respectively. Human milk apparently protects this ethnic group from iron deficiency anemia and this protection seems to be better in mapuche infants than in other groups of chilean infants, because these late have shown 30% incidence of anemia around the first year of life in other studies. More studies on differences in iron nutritional state among mapuche and non mapuche are needed and are under way.

Anemia, Hypochromic↗