Biomedical subjects

D Pineda

Publications and source records attributed to D Pineda.

10 recordsLinked to original sources

PubMed2001

A novel Cys212Tyr founder mutation in parkin and allelic heterogeneity of juvenile Parkinsonism in a population from North West Colombia.

We report the molecular characterization of three multiplex families and a sporadic case of juvenile Parkinsonism identified in the province of Antioquia (Colombia). Linkage and haplotype analysis using markers in 6q25.2-27 indicated that Parkinsonism in the pedigrees is linked to the parkin gene (maximum LOD-score of 3.85) but that they carry two different mutant haplotypes. Sequence analysis revealed a novel G to A transition in exon 6 at position 736 (G736A) of parkin. This change results in a non-conservative cysteine for tyrosine substitution. All affected individuals from two families were homozygous for this mutation, which was not detected in 100 normal controls. Patients from the family carrying the second haplotype and the sporadic case were homozygous for a GT insertion in exon 3. This mutation has been previously identified in French families with juvenile Parkinsonism. The concomitant presence of founder effects and allelic heterogeneity in Antioquia might relate to the founding admixture at the origin of this population.

Adolescent↗

PubMed2000

Searching for the prototypic eye genetic network: Sine oculis is essential for eye regeneration in planarians.

We have identified a sine oculis gene in the planarian Girardia tigrina (Platyhelminthes; Turbellaria; Tricladida). The planarian sine oculis gene (Gtso) encodes a protein with a sine oculis (Six) domain and a homeodomain that shares significant sequence similarity with so proteins assigned to the Six-2 gene family. Gtso is expressed as a single transcript in both regenerating and fully developed eyes. Whole-mount in situ hybridization studies show exclusive expression in photoreceptor cells. Loss of function of Gtso by RNA interference during planarian regeneration inhibits eye regeneration completely. Gtso is also essential for maintenance of the differentiated state of photoreceptor cells. These results, combined with the previously demonstrated expression of Pax-6 in planarian eyes, suggest that the same basic gene regulatory circuit required for eye development in Drosophila and mouse is used in the prototypic eye spots of platyhelminthes and, therefore, is truly conserved during evolution.

Amino Acid Sequence↗

PubMed1999

Prevalence of attention-deficit/hyperactivity disorder symptoms in 4- to 17-year-old children in the general population.

The purposes of this study were (a) to estimate the prevalence of Attention-Deficit/Hyperactivity Disorder (AD/HD) symptoms in the general preschool and school population; and (b) to analyze the influence of gender, age, and socioeconomic status (SES) variables on AD/HD symptoms. Out of the 80,000 preschool and schoolchildren living in Manizales, Colombia, a random sample of 540 children was selected. Two gender, three age (4- to 5-year olds, 6- to 11-year olds, and 12- to 17-year olds), and three SES (low, middle, and high) groups were used. The 18 DSM-IV symptoms corresponding to AD/HD Criterion A were assessed on a scale of 0 (never) to 3 (almost always). All three demographic variables established statistically significant differences: AD/HD symptoms were more frequent in 6- to 11-year-old, low-SES, male participants. DSM-IV Criterion A for AD/HD was fulfilled by 19.8% of the boys and 12.3% of the girls. However, this difference was marginally significant only in the AD/HD Subtype I: Combined. It was concluded that demographic variables are significant correlates of the AD/HD diagnosis. The prevalence found in this study was higher than usually reported, even though only the symptomatic DSM-IV AD/HD criterion was analyzed. We failed to confirm the assumed AD/HD gender ratio.

Adolescent↗

PubMed1999

High altitude living: genetic and environmental adaptation.

High altitude (HA) living produces physiological changes for adaptation to chronic hypobaric-hypoxemic conditions. Although much is known about these physiologic adaptations, no clear separation has been made regarding what is "native" or "genetic" adaptation and what is "acquired." In this review, we describe the genetic vs. acquired adaptation and only include studies performed in a population native to HA and not in an acclimatized population or trekkers. The changes encountered in animals and humans living at HA in terms of hematology, muscular, respiratory, cerebral, cardiovascular, hormonal, fluid and electrolytes and reproduction, strongly suggest that genetics play a very important role in HA adaptation. Unfortunately, the characteristic physiology of HA natives has not been systematically defined to established specific measurable parameters of adaptation in comparison to the acquired ambient adaptation of the non-native population. Once the parameters are established, we can compare non-native populations exposed to HA that must emulate the HA physiology for a definite adaptation to be present. With measurable parameters, especially in the management of fluids and electrolytes, we can define how long it will take for a sea level native to adapt to an HA altitude. Until these studies are performed, speculation will continue and no rational medical intervention can be offered to HA newcomers who may experience HA difficulties.

Adaptation, Physiological↗

PubMed1998

Executive dysfunctions in children with attention deficit hyperactivity disorder.

One hundred and twenty-four male children ranging in age from seven to 12 years-old were selected. The sample was divided into two groups: (1) sixty-two with attention deficit hyperactivity disorder (ADHD) children; and (2) sixty-two normal matched controls (N-ADHD). Three tests were individually administered: (1) Wisconsin Card Sorting Test (WCST); (2) Verbal fluency and semantics (animals and fruits); and, (3) Picture Arrangement subtest of the WISC-R. For all the test scores, statistically significant differences were found between both ADHD and N-ADHD groups. Two separate factor analyses were performed, using the normal and ADHD groups. Four factors were found for the N-ADHD group, which accounted for 85.7% of the variance. The factor structure presented some similarities in both groups: Factor 2, 3 and 4 in the control group corresponded to factors 1, 2 and 3 in the ADHD group. Nonetheless, in the ADHD group Factor 1 (Abstraction and Flexibility Factor) was absent. Results are interpreted as supporting the hypothesis of executive dysfunction in children with ADHD.

Attention Deficit Disorder with Hyperactivity↗

PubMed1998

Individual differences in memory and executive function abilities during normal aging.

The purpose of this study was to analyze the effects of some individual variables on memory and executive function test performance in normal aging individuals. Sixty subjects (21 males and 39 females), with a mean age of 69.66 (SD = 7.09) were selected. The following neuropsychological tests were selected. The following neuropsychological tests were administered: Associative Learning and Logical Memory from the Wechsler Memory Scale (WMS) (Wechsler, 1945), Associative Memory with Semantic Enhancement Test (AMSET) (Pineda, Galeano and Giraldo, 1991), Wisconsin Card Sorting Test (WSCT) (Heaton, 1981), and Verbal Fluency (phonologic and semantic). The effects of demographic (age, education, and sex) and some individual variables (academic history, working history, physical activity, and leisure activities) were measured. Age and education effects on test scores were observed, but no sex effect was found. Working history and leisure activities established significant differences in some test scores. A multiple regression analysis was performed. Not only demographic variables, but also individual variables were associated with memory, and albeit at a lesser extend, with executive function test scores. It was emphasized that not only demographic factors, but also individual variables have a significant effect on cognitive changes observed during normal aging.

Aged↗

PubMed1998

Partial renal resistance to arginine vasopressin as an adaptation to high altitude living.

BACKGROUND: The normal physiological response to high altitude (HA) is a decrease in total body water (TBW) and plasma and extracellular volume. The present investigation was designed to determine the mechanisms of the decrease in TBW with HA adaptation. METHOD: There were 10 men from the Southern Colombian Andes (2600 m) in Pasto, Colombia, who were compared to age-matched men from sea level (SL), Tampa, FL, in the U.S., with respect to their TBW, ability to handle a water load and response to exogenous arginine vasopressin (AVP). Measurements included circulating AVP, atrial natriuretic peptides [atrial natriuretic factor (ANF) and vessel dilator], and urinary excretion of the AVP sensitive water channel, aquaporin-2 (AQP2). RESULTS: The HA subjects had significantly (p < 0.01) lower TBW (29.37 +/- 0.98 vs 39.71 +/- 1.66 Kg), AQP2 excretion and vessel dilator circulating levels at baseline compared to SL subjects. ANF levels were not significantly different between the two groups. With water loading (20 ml.kg-1 in 15 min) there was a rapid increase in urine volume at 30 min with a decline thereafter in HA subjects while SL subjects had a gradual increment peaking at 120 min. There was a significant (p < 0.05) decrease in plasma AVP in the SL subjects within 30 min after the water load while the HA subjects had no significant decrease in AVP levels. Excretion of AQP2 decreased significantly after the water load only in the SL subjects. Administration of exogenous AVP increased AQP2 3- to 4-fold in the HA in comparison to SL subjects. CONCLUSIONS: Present data demonstrate the following adaptations to HA: decrease in TBW, better ability to handle a water load despite high levels of AVP, a significant decrease in the circulation of vessel dilator, and diminished excretion of AQP2 water channel. These findings indicate an insensitivity of the collecting duct of HA subjects to the actions AVP. However, exogenous administration of AVP caused a marked excretion of AQP2.

Acclimatization↗

PubMed1997

[Prevalence of neurocysticercosis in individuals affected by epilepsy].

INTRODUCTION: In this investigations, was carried out a neurocysticercosis (NC) prevalence study during seven months in the Instituto Neurológico de Antioquia with the purpose of known neurocysticercosis frequency as cause of epilepsy in patients older than ten years that we attended in our institute. MATERIAL AND METHODS: Computerized tomographies (CT) were made to 503 patients, with epilepsy, 24.7% of them were CT positive for NC. Cysticercosis enzyme linked immunoelectrotransfer blot (EITB) and enzyme linked immunoabsorbent assay (ELISA) test were made to 178 patients, 19.6% were EITB positive for NC and 5% ELISA positive for NC. Results. From this result it is possible to infer that about 8% of the 503 patients with epilepsy had cysticercosis, according to EITB that is the golden assay for NC. The CT and ELISA test had 94.3% and 27.7% sensitivity, respectively, according to EITB. The specificity of the CT for NC was 49.2% and specificity for ELISA test was 100% as compared to EITB. The multivariate analysis with logistic regression allowed to establish association of positive EITB with factors such as male sex, eating pork, headaches and multiple lesions in CT. CONCLUSIONS: Prevention and education actions are necessary for the interruption of the neurocysticercosis transmission chain in order to diminish the high prevalence of epilepsy in the country and its complication and consequences.

Adult↗

PubMed1995

The effects of high altitude on hypothalamic-pituitary secretory dynamics in men.

OBJECTIVE: Individuals adapted to high altitude (HA) have abnormalities in endocrine function and specifically in the pituitary-thyroid axis and aldosterone regulation. In this study we assessed hypothalamic-pituitary function in men adapted to high altitude living using exogenous administration of synthetic hypothalamic hormones. DESIGN: Growth hormone releasing hormone (Geref 1-29) 1 microgram/kg, TRH 500 micrograms, GHRH 100 micrograms and ovine corticotrophin releasing hormone (oCRH) 1 microgram/kg were simultaneously administered intravenously to two groups of men: 12 born and raised in the city of Pasto, Colombia, South America, located at an altitude of 2600 m in the southern Colombian Andes (HA group) and 10 men living at sea level (SL) in Tampa, Florida. MEASUREMENTS: The following hormones were measured: GH, IGF-I, TSH, T4, free T4, free T3, PRL, ACTH, beta-endorphin and cortisol. IGF binding protein-3 (IGFBP-3) and cortisol binding globulin (CBG) were also measured. RESULTS: GH response to GHRH in HA men was exaggerated compared to SL men, and IGF-I concentration was also significantly increased in the presence of normal levels of IGFBP-3. No differences in TSH or PRL responses were found following TRH. HA men had lower basal total T4 levels, but higher free T4 and free T3 concentrations. The basal ACTH concentrations in the HA men were significantly lower than SL, although the response to oCRH was still present. beta-Endorphin basal levels were similar at HA and SL but the response to oCRH at HA was blunted. At HA, basal cortisol levels as well as CBG were elevated compared to SL and, in contrast to SL, did not increase significantly after endogenous ACTH secretion. CONCLUSIONS: This study is the first description of exaggerated GH response to the administration of GHRH in HA men and also of a significant increase in IGF-I concentration in the same subjects in the presence of normal levels of IGFBP-3. An altered hypothalamic-pituitary response was found in HA men after administration of oCRH characterized by a significantly lower basal ACTH concentration at HA, although the response to oCRH was present but the beta-endorphin response to oCRH was blunted. At HA, basal cortisol levels, as well as CBG, were elevated and the cortisol levels did not significantly increase after endogenous ACTH secretion. We have characterized the differences in hypothalamic-pituitary dynamics after the administration of TRH, GnRH and oCRH in HA men comparing their response to age/sex matched SL men.

Adaptation, Physiological↗

PubMedDate not supplied

[Discrimination between genetic factors in attention deficit].

INTRODUCTION AND OBJECTIVE: In order to elucidate the genetic and environmental components involved in the susceptibility to develop attention deficit hyperactivity disorder (ADHD), a complex segregation analysis on nuclear families (n = 53) ascertained from affected probands belonging to Medellín, in the Antioquian State, Colombia, was performed. METHODS AND RESULTS: Models of cohort effect (non-inheritance), multifactorial, recessive major gene, non-major gene component and non-transmission of major gene were rejected. Contrarily, dominant and codominant major gene models and non-multifactorial component could not be rejected. Thus, the better model fitting the data was that of the major gene (dominant/codominant). This major gene explains more than 99.99% of the ADHD phenotypic variance (value of heritability in the mixed model equal to 0.007%), which permit to assume a low aport of the environmental component to the phenotype ADHD. Gene frequency of the major gene was 3% in the general population of Antioquia and its penetrance was closed to 30%. CONCLUSION: Some cautions and aspects related to the bias of the interview and diagnosis of the parents are discussed.

Attention Deficit Disorder with Hyperactivity↗