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Biomedical subjects

W Wiersinga

Publications and source records attributed to W Wiersinga.

8 recordsLinked to original sources
PubMed1998

Thyroid size and thyroid function during pregnancy: an analysis.

An analysis of all available studies of thyroid size and function in pregnancy reveals that thyroid size, estimated by inspection and palpation or measured more accurately by ultrasonography, increases in pregnancy in areas of iodine deficiency but not in those with sufficient iodine. The increase in average thyroid size is within the normal range, and can partly be prevented by treatment with extra iodine or thyroxine. There is a slight transient increase in free thyroxine in the first trimester, probably as a result of physiological stimulation of thyroid function by human choriogonadotrophin. These levels then decrease by about 30% to low normal values in the second and third trimesters of pregnancy in both iodine-depleted and -replete areas. These changes resemble those of non-thyroidal illness and may well play a role in reducing energy expenditure during pregnancy. The increase in thyroid size in iodine-deficient areas is probably due to autoregulatory mechanisms of iodine on thyroid growth. The hypothesis is supported by the fact that, during pregnancy, thyroid volume and thyroid function adapt in a physiological way to meet the increased demands for iodine and energy.

Female↗
PubMed1997

Thyroid volume and urinary iodine in European schoolchildren: standardization of values for assessment of iodine deficiency.

Up to 1992, most European countries used to be moderately to severely iodine deficient. The present study aimed at evaluating possible changes in the status of iodine nutrition in 12 European countries during the past few years. Thyroid volume was measured by ultrasonography in 7599 schoolchildren aged 7-15 years in one to fifteen sites in The Netherlands. Belgium, Luxemburg, France, Germany, Austria, Italy, Poland, the Czech and Slovak Republics, Hungary and Romania. The concentrations of urinary iodine were measured in 5709 of them. A mobile unit (ThyroMobil van) equipped with a sonographic device and facilities for the collection of urine samples visited all sites in the 12 countries. All ultrasounds and all urinary iodine assays were performed by the same investigators. The status of iodine nutrition in schoolchildren has markedly improved in many European countries and is presently normal in The Netherlands, France and Slovakia. It remains unchanged in other countries such as Belgium. There is an inverse relationship between urinary iodine and thyroid volume in schoolchildren in Europe. Goiter occurs as soon as the urinary iodine is below a critical threshold of 10 micrograms/dl. Its prevalence is up to 10 to 40% in some remote European areas. This work produced updated recommendations for the normal volume of the thyroid measured by ultrasonography as a function of age, sex and body surface area in iodine-replete schoolchildren in Europe. This study proposes a method for a standardized evaluation of iodine nutrition on a continental basis, which could be used in other continents.

Adolescent↗
PubMed1991

Incidence, predictability, and pathogenesis of amiodarone-induced thyrotoxicosis and hypothyroidism.

PURPOSE: To determine the incidence and predictability and to elucidate the pathogenesis of amiodarone-induced thyrotoxicosis (AIT) and hypothyroidism (AIH). PATIENTS AND METHODS: A prospective study was performed in 58 consecutive euthyroid patients living in an area with moderately sufficient iodine intake, who had never been treated for thyroid disease and who started amiodarone therapy for the first time. MAIN OUTCOME MEASURES: Development of thyrotoxicosis or hypothyroidism. RESULTS: The follow-up period was 6 to 54 months (mean, 21 months). The incidence of AIT was 12.1%. A steady occurrence of new cases was observed. The development of AIT was unpredictable and of unexplained sudden onset. The incidence of AIH was 6.9%. All AIH cases occurred early in the course of amiodarone therapy. The development of AIH was related to pre-existent thyroid disease: the relative risk for women with microsomal and/or thyroglobulin autoantibodies prior to treatment was 13.5 (95% confidence interval 3.2 to 57.4). The development of AIT or AIH was not related to the extent of iodine overload or to the occurrence of de novo thyroid autoantibodies. When a decreased thyrotropin (TSH) response to thyrotropin-releasing hormone occurred (in the absence of AIT), continuation of amiodarone medication was associated with a normalization of the TSH response in eight of 11 cases (73%); in contrast, an increased TSH response (in the absence of AIH) returned to normal in one of four cases (25%). CONCLUSION: In euthyroid subjects living in an area with a moderately sufficient intake of iodine, there is a higher incidence of AIT than of AIH. AIH is an early event, occurring especially in women with thyroid autoantibodies prior to treatment. Cases of AIT continue to occur during amiodarone therapy; its development is unpredictable and of unexplained sudden onset. The value of regular thyroid function testing is therefore limited during amiodarone administration.

Adult↗
PubMed1990

Five-year cimetidine maintenance trial for peptic ulcer disease. A clinical and endocrinologic approach.

A multicentre maintenance trial was conducted in 63 peptic ulcer patients to investigate the efficacy and safety of continuous cimetidine maintenance therapy for up to 5 years. In Amsterdam the male patients were investigated yearly for possible endocrinologic changes and to monitor gastric acid secretory capacity. Patients with healed ulcers entered maintenance treatment with a 400-mg bedtime dose of cimetidine. The yearly relapse rates decreased from 20% to 6% from year 1 to year 4. Adverse reactions observed in this study were not different from those previously reported with cimetidine. Endocrinologic studies in 10 male patients showed a small but consistent increase in basal gastrin in the 3rd and 4th year, stabilizing in the 5th year. Prolactin levels showed a gradual increase during the first 3 years but remained well within the normal range. In the 4th and 5th year they decreased again; however, the changes noted were rather modest. It is concluded from this study that weak nocturnal acid inhibition with cimetidine maintenance treatment not only continues to be effective and safe beyond 1 year but also reduces the risk of relapse over time. No relevant endocrinologic abnormalities are to be expected with this regimen of modest nocturnal acid suppression.

Adult↗
PubMed1989

Comparison of beclomethasone dipropionate (2 and 3 mg) and prednisolone sodium phosphate enemas (30 mg) in the treatment of ulcerative proctitis. An adrenocortical approach.

Twenty-three patients with attacks of distal ulcerative colitis were treated randomly with either 2 or 3 mg of topically administered beclomethasone dipropionate (BDP) or 30 mg of prednisolone sodium phosphate (PP). The effect of the steroid enemas on adrenocortical function was assessed by ACTH tests, which were performed before and after treatment. Endoscopic, clinical and histological scores were comparable in the three treatment groups in this pilot trial. Fasting cortisol in the PP group decreased significantly from 0.47 +/- 0.12 mumol/l before to 0.22 +/- 0.14 mumol/l (P less than 0.05) after therapy; in the BDP group no significant changes were found. Urinary cortisol excretion in the PP group was not detectable after therapy; in the BDP group no changes were found. It is concluded that in the topical treatment of ulcerative colitis, BDP may be preferable to PP because it exerts a promising anti-inflammatory action without affecting adrenocortical function.

Adult↗