Ricardo V. García-Mayor

Prevalence and incidence of hypopituitarism in an adult Caucasian population in northwestern Spain

OBJECTIVE To determine the prevalence and incidence of hypopituitarism in the general population.

Time trends for thyroid cancer in northwestern Spain: true rise in the incidence of micro and larger forms of papillary thyroid carcinoma.

BACKGROUND Thyroid cancer incidence is increasing throughout the world. Most studies attribute this rise entirely to the increase in papillary carcinoma, the most common thyroid malignancy in iodine-sufficient areas. A variety of nonetiological factors such as changes in clinical practice may affect the incidence of thyroid cancer and some researchers have suggested that this rise is only apparent due to an increase in diagnostic activity. Since data on the epidemiology of thyroid cancer in Spain are scarce, the main goal of this study was to analyze changes in thyroid cancer presentation, incidence, and prevalence in Vigo (northwestern Spain) between 1978 and 2001, and to investigate the relationship between the incidence rates and trends in tumor size and thyroid surgery. METHODS In this descriptive epidemiologic study, an analysis was carried out on new thyroid cancer cases obtained from the Pathology Registry of the University Hospital of Vigo (500,000 inhabitants). Trends in age, sex, thyroid surgery, histological type, tumor size, and incidence rates were calculated. The prevalence of thyroid cancer was determined in three cross-sectional surveys. RESULTS The rate of population undergoing thyroid surgery significantly increased over time. Out of 322 new primary thyroid cancers, papillary thyroid cancer (PTC) was the predominant type (76%). The age-standardized incidence rate shows a significant increase in females: 1.56 per 100,000 year (1978 to 1985) to 3.83 (1986 to 1993) and 8.23 (1994 to 2001); and in males: 0.33, 1.19, and 2.65, respectively. PTC was mainly responsible for this pattern and was the result of both the increase in micropapillary thyroid carcinoma (MPTC) incidence and in PTC measuring more than 1 cm. Besides MPTC cases, no significant variations were observed in tumor size over time. CONCLUSIONS In northwestern Spain, the incidence of thyroid cancer is increasing. These data should be taken into account when planning health resources for these patients. Our results may reflect the contribution that other factors, besides increased diagnostic activity, have made to the rise in thyroid cancer incidence in our region. Additional studies are needed to explain the rise in PTC incidence throughout the world and to search for potential risk factors that are currently unrecognized.

Serum leptin levels in women throughout pregnancy and the postpartum period and in women suffering spontaneous abortion

In pregnancy, important changes occur in the body weight of the mother, caused by sodium and water retention and by an increase in body fat tissue, but the mechanisms that regulate maternal and foetal changes in fat mass are poorly understood. Leptin is a hormone produced by adipocytes in order to regulate food intake and energy expenditure at the hypothalamic level in man. In order to verify whether leptin participates in the changes in body composition during pregnancy and postpartum, 630 healthy women were studied at specific time periods and leptin and auxological parameters were determined.

Déficit de yodo en gestantes y mujeres en edad fértil pertenecientes a un área con consumo normal de yodo

El deficit nutricional de yodo puede causar un amplio espectro de enfermedades que afectan a personas de todas las edades, pero particularmente a las mujeres embarazadas y al desarrollo fetal y neonatal 1 . El embarazo se acompana de importantes cambios en la economia tiroidea 2 . En areas con suficiente consumo de yodo, estos cambios mantienen la funcion tiroidea estable a pesar del aumento de los requerimientos hormonales, pero cuando existe una toma deficitaria estos ajustes se hacen de forma patologica3. La importancia de todo esto radica en que el desarrollo fetal y, en particular, la organogenesis cerebral dependen del yodo y de las hormonas tiroideas maternas 4

High serum leptin levels in children with type 1 diabetes mellitus : Contribution of age, BMI, pubertal development and metabolic status

Children with diabetes mellitus are prone to develop obesity and to experience a delay in onset of the pubertal process. In order to understand the role of leptin in these abnormalities, serum leptin levels were analysed in children with type 1 diabetes mellitus.

Disordered eating behaviors in type 1 diabetic patients

Patients with type 1 diabetes mellitus are at high risk for disordered eating behaviors (DEB). Due to the fact that type 1 diabetes mellitus is one of the most common chronic illnesses of childhood and adolescence, the coexistence of eating disorders (ED) and diabetes often affects adolescents and young adults. Since weight management during this state of development can be especially difficult for those with type 1 diabetes, some diabetics may restrict or omit insulin, a condition known as diabulimia, as a form of weight control. It has been clearly shown that ED in type 1 diabetics are associated with impaired metabolic control, more frequent episodes of ketoacidosis and an earlier than expected onset of diabetes-related microvascular complications, particularly retinopathy. The management of these conditions requires a multidisciplinary team formed by an endocrinologist/diabetologist, a nurse educator, a nutritionist, a psychologist and, frequently, a psychiatrist. The treatment of type 1 diabetes patients with DEB and ED should have the following components: diabetes treatment, nutritional management and psychological therapy. A high index of suspicion of the presence of an eating disturbance, particularly among those patients with persistent poor metabolic control, repeated episodes of ketoacidosis and/or weight and shape concerns are recommended in the initial stage of diabetes treatment, especially in young women. Given the extent of the problem and the severe medical risk associated with it, more clinical and technological research aimed to improve its treatment is critical to the future health of this at-risk population.

Metabolic clearance rate of biosynthetic growth hormone after endogenous growth hormone suppression with a somatostatin analogue in chronic renal failure patients and control subjects

OBJECTIVE Several disturbances in the regulation of growth hormone secretion have been reported in chronic renal failure. The general assumption is that an altered hormonal clearance is at the basis of such GH alterations. Nevertheless, details of GH elimination kinetics in uraemia are not available. To clarify the role played by the kidney in its catabolism, GH elimination kinetics were studied in uraemic and control subjects after suppression of endogenous secretion of GH.

Novel point mutation in exon 10 of the RET proto-oncogene in a family with medullary thyroid carcinoma.

Medullary thyroid carcinoma (MTC) may occur sporadically or as part of the autosomal dominant multiple endocrine neoplasia type 2 (MEN 2). Three hereditary forms of MEN 2 have been identified: MEN 2A, MEN 2B, and familial MTC (FMTC). Missense germ-line mutations in the RET proto-oncogene have been identified as cause of these endocrine diseases. Mutations are found in exons 10 and 11 in MEN 2A and FMTC families and in a small number of families in exons 13, 14, and 15. Although a strong correlation between codon mutations and phenotypes has been described, not all the expected cystein codon mutations have been found. Therefore, the more mutations are found, the better it is possible to establish phenotype-genotype correlations. We report on a novel RET mutation at codon 611 in a family with MTC without other clinical manifestations and of rather benign course.

A single growth hormone (GH) determination is sufficient for the diagnosis of GH‐deficiency in adult patients using the growth hormone releasing hormone plus growth hormone releasing peptide‐6 test

background The diagnosis of GH deficiency in adults is based on the provocative testing of GH secretion. When testing a patient with suspected GH deficiency, clinicians assess the whole secretory curve and select the GH peak as an index of secretory capability. This procedure is time consuming and the determination of GH in several samples is necessary. The combined administration of growth hormone releasing hormone (GHRH) plus growth hormone releasing peptide‐6 (GHRP‐6) is an effective test of GH secretion, and it has been unambiguously demonstrated that the elicited GH peak is capable of segregating normal GH secretion subjects from GH deficient patients on an individual basis. The GHRH + GHRP‐6 test biochemically classifies patients into three groups; those with a stimulated GH peak ≥ 20 µg/l are considered normal and those with peaks at ≤ 10 µg/l as GH deficient. The group comprising individuals between these parameters is considered uncertain, and the results are further interpreted according to clinical information, or by other tests.

Regulation of growth hormone secretion by the growth hormone releasing hexapeptide (GHRP-6).

Growth hormone (GH) secretion is regulated by a complex system of central and peripheral signals. Recently, a new GH-releasing hexapeptide (His-D-Trp-Ala-Trp-D-Phe-Lys-NH2) called GHRP-6 which specifically releases GH has been studied. In the present work the mechanism of action of GHRP-6 has been addressed in experimental animal models as well as in obese subjects. GHRP-6 releases GH independently of the hypothalamic factors GHRH and somatostatin and is a powerful GH releaser in obesity.