Arnaldo Foradori C

Anticuerpos anti-tiroglobulina en el seguimiento de pacientes con cáncer diferenciado de tiroides: ¿Marcadores de enfermedad residual o recidivante?

Background: Anti thyroglobulin antibodies are present in 25% of patients treated for a differentiated thyroid cancer, invalidating thyroglobulin determination. Those patients subjected to total thyroidectomy and free of disease, should reduce the production of these antibodies, due to the lack of antigenic stimulus. Therefore, anti thyroglobulin antibodies could be useful to detect early relapses. Aim: To assess the relationship between anti thyroglobulin antibodies and the evolution of the disease in patients treated for thyroid cancer. Material and methods: Retrospective analysis of 26 patients treated for thyroid cancer with positive anti thyroglobulin antibodies, followed for three years. These were divided in those with or without lymphocytic thyroiditis (19 and 7 respectively). Results: At the first year of follow up, anti thyroglobulin antibody concentration was 401±94.9 UI/ml (x±sem) in patients with thyroiditis and 38.9±8.9 UI/ml in those without thyroiditis (p < 0.005). During the three years of follow up, no differences in anti thyroglobulin antibodies were observed between patients with or without tumor relapse. Conclusions: Concentration of anti thyroglobulin antibodies was higher in patients with thyroiditis and did not differentiate patients with tumor relapse (Rev Med Chile 2002; 130: 167-72)

Identificación de mutaciones en el gen CFTR en pacientes chilenos con fibrosis quística

Background: Cystic fibrosis (CF) is an autosomal recessive disease caused by mutations in the CFTR gene, that codes for a chloride channel located in the apical surface of epithelial cells. The main role of this protein is the regulation of chloride transport, and secondarily, of sodium and water to the extracellular space. More than 900 gene mutations have been described, and their relative frequency in different populations depends on their ethnic origin. Aim: To report the findings of Chilean patients with cystic fibrosis, in whom the presence of 20 common mutations was analyzed. Patients and methods: Fifty seven patients with established diagnosis or suspicion of CF were studied. The simultaneous identification of 20 mutations and the normal DF508 allele was done using polymerase chain reactions with a commercial assay. Results: Eight mutations were found. Fifty patients fulfilled diagnostic criteria proposed by the Consensus Panel of the CF Foundation and 66% of alleles were identified in this group. ∆F508 mutation was found in 45%. We did not identify mutations in any of the remaining 7 patients. Conclusions: Our results suggest that the majority of undetected mutations are associated with atypical phenotypes or that some patients in this series could have other diseases. We recommend to include mutation analysis in the evaluation of Chilean patients with CF. It is useful to establish prognosis and genetic counselling (Rev Med Chile 2001; 129: 841-7).

Exceso de mineralocorticoides en hipertensos esenciales: enfoque clínico-diagnóstico

Background: Primary hyperaldosteronism is more frequent among subjects with essential hypertension than previously thought. The prevalence, according to local and international evidence could fluctuate between 9 and 10%. Aim: To investigate if subjects with essential hypertension have different aldosterone and renin plasma levels than normotensive subjects. Patients and methods: One hundred twenty five subjects with essential hypertension, not receiving medications for at least two weeks prior to the study and 168 age and sex matched normotensive controls were studied. Blood was drawn between 9 and 10 AM during a sodium free diet to determine plasma aldosterone, plasma renin activity and potassium. Results: Plasma aldosterone was higher in hypertensive subjects than controls (11.6 ± 7.6 and 9.9 ± 5.1 ng/dl respectively; p=0.04). Plasma renin activity was lower in hypertensives than controls (1.42 ± 1.28 and 1.88 ± 1.39 ng/ml/h respectively; p<0.001). Thus, plasma aldosterone/plasma renin activity ratio was higher in hypertensives (13.8 ± 13.5 and 8.3 ± 7.8; p<0.001). A pathological ratio was defined as over 25, corresponding to the mean plus two standard deviations of the control group. Primary hyperaldosteronism was found in 5/125 hypertensives (4%) and 1/168 normotensive subject (0.6%). None had hypokalemia. Conclusions: Subjects with essential hypertension have higher plasma aldosterone and lower plasma renin activity than normal controls. A plasma aldosterone/plasma renin activity over 25 was defined as abnormal. (Rev Med Chile 2000; 128: 955-61)

Alta prevalencia de enfermedad tiroidea subclínica en sujetos que concurren a control de salud

Background: There is no information about the prevalence of thyroidal diseases in the general Chilean population. Aim: To assess the prevalence of thyroidal diseases in individuals attended in occupational health examinations. Subjects and methods: Four hundred seventy two individuals were examined between 1998 and 1999. In all, serum levels of thyroid hormones, TSH and anti thyroidal antibodies (anti microsomal, anti thyroid peroxidase and anti thyroglobulin) were measured. Results: Forty four subjects were excluded from the study due to an incomplete medical record and 18 due to a personal history of thyroidal disease. Abnormal serum levels of thyroid hormones or TSH were detected in 28 subjects (6.8%). Four (1%) had hypothyroidism, 23 a subclinical hypothyroidism (5.6%) and one (0.2%) had hyperthyroidism. In 87 subjects (21.2%) at least one of the antibodies was positive. Positive anti thyroid antibodies were found in 14 of 28 subjects (50%) with abnormal thyroid hormone levels, compared with 73 of 382 subjects (19.1%) with normal thyroid hormone levels. Thyroid dysfunction was twice as frequent in women than in men. Conclusions: In this sample, a 6.8% prevalence of abnormal thyroid function tests was detected. (Rev Med Chile 2001; 129: 155-60).

Correlación genotipo-fenotipo de un grupo de pacientes con fibrosis quística

Background: Cystic fibrosis (CF) is the most common lethal autosomic disease in Caucasians, with a global incidence of 1:3000 newborns. More than 900 mutations have been described, involving the Cystic Fibrosis Transmembrane Regulator (CFTR). The ∆F508 mutation is present in 60% of alleles studied worldwide. Aim: To report 25 patients with cystic fibrosis in whom a genetic study was done. Material and methods: Twenty five patients (14 men, aged between 18 months and 25 years) with a diagnosis of cystic fibrosis based on clinical features plus two abnormal sweat tests are reported. The genetic study considered the 20 most common mutations in cystic fibrosis and was done in genomic DNA of peripheral lymphocytes, by polymerase chain reaction. Results: A mutation was found in 75% of analyzed alleles. DF508 was present in 50% of cases (DF508/DF508 in 8 and DF508/other in 11). When DF508 was present, pancreatic insufficiency was always a feature and nutritional status was worse. Respiratory involvement was variable, both for homozygous and heterozygous cases. Other severe mutations such as W1282X and G542X were related to clinical manifestations similar to those found in DF508 mutation. Diagnosis was made before six months of age in 12 patients. The clinical presentation was meconium ileus and there was a family history of the disease in most cases. The majority of cases of early diagnosis presented severe mutations, but milder respiratory symptoms and lesser nutritional compromise at the time of assessment. Conclusions: Most patients studied had a severe cystic fibrosis mutation, which was associated with more severe respiratory, pancreatic and nutritional involvement. The early diagnosis of the disease, which would allow to improve the prognosis and the quality of life, must be emphasized (Rev Med Chile 2002; 130: 475-81)

Niveles de vitamina D en adultos mayores saludables chilenos y su relación con desempeño functional

: Healthy subjects aged 60 years or more and living in the community were invited to participate. People with chronic diseases, cognitive impairment, physical disability, smokers and those consuming more than three medications per day were excluded. Hand grip and gait speed were measured and a blood sample was obtained to measure 25OH vitamin D by radioimmunoanalysis.BACKGROUND People over 60 years old are at risk of Vitamin D deficiency, which can affect functional performance, since this vitamin is involved in muscle function and protein synthesis. AIM To measure 25OH vitamin D levels in healthy older people from Santiago de Chile, and evaluate their relationship with functional performance. SUBJECTS AND METHODS Healthy subjects aged 60 years or more and living in the community were invited to participate. People with chronic diseases, cognitive impairment, physical disability, smokers and those consuming more than three medications per day were excluded. Hand grip and gait speed were measured and a blood sample was obtained to measure 25OH vitamin D by radioimmunoanalysis. RESULTS One hundred and four participants aged 60 to 98 years (55% females) were studied. Mean vitamin D levels were 17.3 ± 6.1 ng/mL. Females had lower levels than males (15.6 ± 5.8 and 19.2 ± 6.0 ng/mL respectively p < 0.01). Eighty three percent of females and 55.3% of males had values below 20 ng/mL (the cutoff point for deficiency). Only 3.5% of females and 8.5% of males had values of 30 ng/ml or higher. There was a significant correlation between vitamin D levels, gait speed and grip strength (r = 0.32 and 0.34 respectively, p < 0.01), especially in women over 74 years. CONCLUSIONS Vitamin D deficiency is almost universal in healthy adults over 60 years living in Santiago de Chile, especially in women. This deficiency is associated with a deranged functional performance and is a potentially modifiable risk factor for disability.