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Biomedical subjects

A Cattani

Publications and source records attributed to A Cattani.

At least 19 recordsLinked to original sources
PubMed2001

[Clinical and molecular study of Chilean patients with McCune-Albright syndrome].

BACKGROUND: McCune-Albright Syndrome (MAS) is characterized by precocious puberty, "cafe au lait" skin lesions and polyostotic fibrous dysplasia. It is caused by 4 post-zygotic mutations of G alpha s protein with a mosaic distribution. AIM: To describe the clinical presentation and to investigate the presence of the Arg by his substitution (R201H) in 14 girls with MAS. PATIENTS AND METHODS: We performed a clinical analysis of the patients and specific allele PCR in DNA obtained from leukocytes. RESULTS: Twelve of 14 patients presented with precocious puberty, one with cyclical vaginal bleeding and one with pathological bone fractures. Eight girls had polyostotic fibrous dysplasia, one had hyperthyroidism, four had pathological fractures, ten had ovarian cysts, six had breast hyperpigmentation and ten had "cafe au lait" skin lesions. We detected the R2O1H mutation in 10 of 14 patients. We found no difference in the severity of symptoms or in the age of presentation between the patients with and without the mutation. CONCLUSIONS: The R201H mutation can be detected in white blood cells, in approximately 70% of cases. Patients exhibit wide clinical variability with the same molecular defect. This suggests that tissues have different proportions of mutant cells.

Adolescent↗
PubMed2000

Mutations in the CYP21 B gene in a Chilean population with simple virilizing congenital adrenal hyperplasia.

Steroid 21-hydroxylase deficiency (21OHD) compromises about 95% of all cases of congenital adrenal hyperplasia. We have characterized the disease-causing mutations in the steroid 21-hydroxylase genes of 19 Chilean patients (12 females and 7 males) with the simple virilizing (SV) form of 21OHD and compared them with other SV-populations. Using allele-specific polymerase chain reaction, we identified lesions in 28 chromosomes out of 38 tested (73.7%). The most frequent finding was the mutation I173N=12/38 (31.6%) similar as described in Caucasian, Asian and other Hispanic populations, where this mutation represents around 20-40% of the genetic defects in the CYP21B gene. The mutation V282L=4/38 (10.5%) and deletion (Del) or large gene conversion (LGC)=3/38 (7.9%) were also frequently detected. Only 2 alleles carried the mutation I2 splice (5.3%), this frequency is lower than that reported in Caucasian or in Mexican populations. We did not find alleles with the mutations R357W, Cluster E6, P31L and P454S in these patients. The complete genotype was determined in 11/19 patients (58%) and one allele in 6/19 patients (31.6%). In summary, about 30% of the Chilean population with SV 21OHD presented the missense mutation I173N as described in other populations. The frequency of the other lesions showed differences even between populations with similar genetic background.

Adrenal Hyperplasia, Congenital↗
PubMed2000

[Bone turnover in lactating adolescent: evaluation at the end of pregnancy, during and after the weaning period].

BACKGROUND: There is paucity of information about bone metabolism during pregnancy or breast feeding in teenagers. AIM: To study bone turnover at the end of pregnancy and during breast feeding in teenagers and correlate it with environmental, hormonal or nutritional variables. SUBJECTS AND METHODS: Thirty teenagers during their breast feeding period after a first pregnancy and 30 nulliparous girls matched for age, age of menarche and body mass index were assessed three weeks after delivery (period 1), at six months of breast feeding (period 2) and one year after the lactating period (period 3). Calcium intake and plasma calcium, phosphorus, alkaline phosphatases, parathormone, estradiol and prolactin were measured. Calcium, creatinine and hydroxyproline were also measured in a morning urine sample. RESULTS: Lactating and control girls were aged 16.3 +/- 0.8 and 16.1 +/- 0.7 years old respectively. Calcium intake in lactating and control girls was 798 +/- 421 and 640 +/- 346 g/day respectively in period 1, 612 +/- 352 and 592 +/- 309 mg/day in period 2 and 495 +/- 180 and 456 +/- 157 g/day in period 3. During periods 1 and 2, lactating girls had higher alkaline phosphatases (161 +/- 37 compared to 119 +/- 28 U/l and 149 +/- 37 compared to 106 +/- 23 U/l), parathormone (4.3 +/- 2.6 compared to 2.8 +/- 0.8 ng/dl and 3.6 +/- 1.6 compared to 3.0 +/- 0.9 ng/dl) and urinary hydroxyproline (95 +/- 16 compared to 63 +/- 15 mg/g creatinine and 84 +/- 19 compared to 59 +/- 15 mg/g creatinine). No differences were observed in period 3. No correlation between bone turnover variables, body mass index or hormonal parameters, was observed. CONCLUSIONS: In teenagers, there is an increase in bone turnover at the end of pregnancy, that persists during the lactating period. These changes are not related to nutritional or hormonal variables.

Adolescent↗
PubMed2000

[Measurement of 17 OH progesterone in blood in Chilean newborns: antecedents for implementing a grogram for the neonatal detection of congenital adrenal hyperplasia].

BACKGROUND: The early diagnosis and therapy of congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency can prevent adrenal crises and erroneous gender assignment in affected newborns. To achieve this goal neonatal mass-screening programs have been developed, measuring blood 17 alpha-hydroxyprogesterone (17OHP). In Chile there is no experience with this type of screening. AIM: To develop a method for measuring 17OHP in filter paper blood specimens. To obtain reference ranges and determine neonatal 17OHP threshold levels according to gestational age and birth weight. To analyze factors affecting the cost-efficiency ratio and suggest recommendations for the organization of a neonatal screening program for CAH in Chile. MATERIAL AND METHODS: Nine hundred twenty two newborns were studied. 17OHP was measured using double antibody radioimmunoassay in filter paper blood samples obtained 48 h after birth. Reference ranges were determined according to gestational age and birth weight and a cutoff point of 25 ng/ml was established. RESULTS: Seventeen newborns had 17OHP over the cutoff value. They were assessed by a pediatric endocrinologist and in none of them, CAH was confirmed. Therefore the false positive rate of the determination was 1.8%. Among these newborns with elevated 17OHP, 66% had a birth weight below 1.5 kg and 5.8%, a birth weight between 1.5 and 2.5 kg. The cost per reported result was US $ 1. Timing of the recall was between the 3 and 10 days of life. No newborn missed the follow-up. DISCUSSION: To increase the cost-efficiency ratio of an eventual neonatal screening program, newborns with birth weights below 1.5 kg should be excluded and cutoff points should be defined according to birth weight (Rev Méd Chile 2000; 128: 1113-18).

17-alpha-Hydroxyprogesterone↗
PubMed1998

Teaching sign language to hearing children as a possible factor in cognitive enhancement.

We describe an educational experience designed to teach Italian Sign Language (LIS) to a group of hearing children. The hypothesis underlying this experience was that learning a visual-gestural language such as LIS may improve children's attentional abilities, visual discrimination, and spatial memory. To examine this hypothesis, we conducted two studies. The first involved an educational experience lasting two years with a group of hearing children attending a Sign Language class from first to second grade. The Raven PM 47 TEST was administered at the beginning and at the end of each school year to children attending the LIS classes and to a control group of children enrolled in the same school but not exposed to LIS. The second study involved an educational experience in first grade. The Raven PM 47 and Corsi's block tapping tests were administered at the beginning and at the end of the school year to the children attending the LIS classes, to children enrolled in the same school but at tending an English class, and to children not exposed to a second language. We found that in both studies the LIS group performed better than the other groups. These results suggest that learning a sign language may lead to a cognitive advancement in hearing children.

Journal Article↗
PubMed1998

Salt-wasting congenital adrenal hyperplasia: detection of mutations in CYP21B gene in a Chilean population.

The steroid 21-hydroxylase deficiency (21OHD) is the most frequent cause of congenital adrenal hyperplasia. We have characterized the disease-causing mutations in the 21-hydroxylase genes of 63 patients with salt-wasting congenital adrenal hyperplasia from a Chilean population of Hispanic origin, a group that has been scarcely evaluated. Using allele-specific PCR, lesions were identified in 97 chromosomes out of 126 tested (77%). The most frequent findings were the gene deletion or large gene conversion (LGC) = 22.9%, I2 splice = 19%, R357W = 12.7%, and Q319X = 10.5%. We did not find alleles with the mutation F308insT and we found three alleles with the cluster E6. The frequency of the point mutation R357W was at least two times more frequent than the one found in Caucasians populations, but similar to that communicated in Asian populations; this finding may be explained by the Asian ancestry of our South-Amerindian population. The frequency of Q319X was also high, similar only to those patients studied in Italy and in a neighboring Argentinian population. In summary, this is a genetic characterization of 21OHD made in an almost pure Hispanic population in Latin America. The high frequency of deletion of CYP21B gene, I2 splice, R357W, and Q319X mutations probably reflects the European-Caucasian-Spanish influence of the conquerors, mixed with Amerindians of Asian ancestry and modulated by other European immigrations.

Adrenal Hyperplasia, Congenital↗
PubMed1997

[Molecular diagnosis of salt wasting congenital adrenal hyperplasia, caused by deficit of 21-hydroxylase, in the Chilean population].

BACKGROUND: The most frequent cause of congenital adrenal hyperplasia, manifested as virilization and salt wasting, is the deficit of 21-hydroxylase. This disease is originated by mutations of the gene CYP21 that codifies this enzyme, mostly recombination between this gene and its inactive pseudogene called CYP21P. AIM: To study the molecular origin of this enzyme deficiency in Chilean patients. PATIENTS AND METHODS: Twenty five patients with salt wasting congenital adrenal hyperplasia, that had 17-hydroxyprogesterone levels above 30 ng/ml, were studied. In all patients, a polymerase chain reaction (PCR) with selective primers was done with extracted genomic DNA, to amplify the active gene and specific primers for normal or mutated alleles (Allele-specific PCR). RESULTS: The affected allele was identified in 39 (78%) of the 50 chromosomes of the 25 patients. The higher frequency affected the ASIn2 in 26% of cases, followed by mutations Arg357Trp in 22% of cases and Gln319Stop in 12% and deletion in 12%. The identification of two affected alleles in a same patient was achieved in 17 cases (68%). The most frequent genotypes were homozygosity for ASIn2 (16%), homozygosity for Arg357Trp (12%) and the homozygote deletion of the gene in 12%. CONCLUSION: The most frequent mechanisms of genetic damage in this population of patients with salt wasting congenital adrenal hyperplasia due to deficiency of 21-hydroxylase were the mutations ASIn2 and Arg357Trp. This type of studies allows prenatal diagnosis and genetic counseling.

Adrenal Hyperplasia, Congenital↗
PubMed1993

[3 beta-hydroxysteroid dehydrogenase defect: frequency of presentation in a sample of Chilean hirsute women].

The defect of 3 beta hydroxysteroid dehydrogenase (3 beta HSD) is frequent among hirsute women and clearly dependent on the ethnic composition of the studied population. Our aim was to study the frequency of 3 beta HSD deficit in a group of Chilean hirsute women. Basal and post ACTH concentrations of cortisol, 17 hydroxyprogesterone and 17 hydroxypregnenolone were measured by RIA in 40 hirsute post puberal women and in 15 normal age matched female volunteers. Criteria for considering a 3 beta HDS deficit were 17 hydroxypregnenolone values and 17 hydroxypregnenolone/17 hydroxyprogesterone and 17 hydroxypregnenolone/cortisol ratios after ACTH stimulation over the 95% confidence intervals of normal women. Basal dehydroepiandrosterone sulphate and testosterone levels were also measured in hirsute women. All samples were obtained during the follicular phase of the menstrual cycle. ACTH stimulated hormone values and ratios were diagnostic for 3 beta HDS deficit in 7.5% of hirsute women. Basal testosterone was over 80 ng/dl in 47.5% and dehydroepiandrosterone sulphate over 3.9 micrograms/ml in 52.5% of these women. There was no correlation between dehydroepiandrosterone or testosterone values and ACTH stimulated hormone values. It is concluded that 3 beta HSD is frequent in hirsute women and that its diagnosis requires the determination of ACTH stimulated 17 hydroxypregnenolone values and 17 hydroxypregnenolone/17 hydroxyprogesterone ratio.

17-alpha-Hydroxypregnenolone↗
PubMed1989

The paradoxical response of growth hormone (GH) to thyrotropin-releasing hormone (TRH) in constitutionally tall children involves a cholinergic pathway.

To investigate whether or not a cholinergic pathway is involved in the paradoxical response of GH to TRH in constitutionally tall children, we studied 8 healthy prepubertal children aged 4 2/12-7 10/12 yr, whose heights were over the 95th percentile of the NCHS tables. We defined as "paradoxical" a GH increment greater than 5 ng/ml in response to TRH. Five out of 8 children showed a paradoxical response of GH to TRH (mean GH peak after TRH of 10.7 +/- 1.1 ng/ml). Pretreatment with atropine (0.01 mg/kg IM 30 min prior to the TRH administration) abolished the TRH induced GH rise (peak GH after TRH of 1.5 +/- 1.0 ng/ml, p less than 0.01) but did not modify the TSH response (peak TSH after TRH: basal conditions 8.7 +/- 0.8 microU/ml, post atropine: 9.5 +/- 1.4 microU/ml, p greater than 0.05). Our results demonstrate that a cholinergic pathway is involved in the paradoxical response of GH to TRH in constitutionally tall children.

Acetylcholine↗
PubMed1978

[Damages of malfunction of the electrostimulating system (author's transl)].

In this study we describe the damages, or the ill-functioning of the electrostimulating system due to failure or bad functioning of the catheter electrode, of the electronic circuits and of the energy sources. Complications due to iatrogen causes or to clinical pathology have not been dealt with. Defects of electrostimulation are described in their clinical, electrocardiographic, oscilloscopic and electrophysiologic aspects, and in the operative report, through the study of 1455 cases. In the differential diagnosis of the defects of electrostimulation we point out their biological causes. The sheath interruption, observed in 31 cases, causes defects in electrostimulation, depending on the extension and on the position of the unsheathing. The circuit variations can be compared with the effect produced by a shunt capacitor. The sheath interruption causes a current reduction which reaches stimulating surface and the differential diagnosis concerns the electronic failure of the generator, the battery discharge, the organic liquid infiltration in the insertion point, the position of the catheter, and the tip perforation of it. The breaking of the spiral (in 6 cases) can be partial or total, and may be compared to the forming of a series capacitor between the electrodes which may sham the increase of the myocardic threshold. The stimulating surface, too wide respecting the intensity supplied by the electrostimulator, brings about a low current density and failures in electrostimulation; the difference between such condition and the one caused by a high myocardiac threshold is shown by determining the safety factor. A very small stimulating surface increases the electrode impedance and may cause a defect of the perception function, if the generator input impedance (4 cases) is reduced. The fall of the output voltage may be caused by a battery discharge, and is the most frequent cause of electrostimulation disturbances; it has been observed in 432 cases. Other causes of the fall of the output voltage (30 cases) are the outflow of mercury from the cells, or mycotic formations. The ill-functionning or the loss of perception (9 cases) caused by defects of the electrostimulator must be distinguished from the ones caused by the endocavitarian potential reduction (myocardiac infarction, conduction disturbances: 2 cases). Variations of the stimulating cycle can be caused by ageing, humidity on resistances and on oscillator condensers (9 cases). Accelerated stimulating was observed in 1 case, plate corrosion in 3 cases, high density of anodic current in 9 cases, generator turnover in 3 cases. Finally we give the chief points of electrical stimulating disturbances due to interferences of electromagnetic radiation.

Cardiac Pacing, Artificial↗