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Biomedical subjects

E Nyström

Publications and source records attributed to E Nyström.

At least 19 recordsLinked to original sources
PubMed2006

Amiodarone inhibits thyroidal iodide transport in vitro by a cyclic adenosine 5'-monophosphate- and iodine-independent mechanism.

Thyroid side effects are common in patients treated for cardiac arrhythmias with amiodarone (AM). A major disturbance is inhibited thyroidal radioiodine uptake in AM-induced thyrotoxicosis, which makes 131I therapy ineffective. On the other hand, failure to escape from the Wolff-Chaikoff effect by down-regulation of the sodium/iodide symporter (NIS) is proposed to explain AM-induced hypothyroidism. However, previously no experimental studies on the possible mechanisms have been conducted. We therefore investigated the early effects of AM on thyroidal iodide transport using bicameral chamber cultures of primary pig thyrocytes that reproduce the three tissue compartments (epithelium, lumen, and extrafollicular space) of the gland. AM dose-dependently (1-50 microm) inhibited the TSH-stimulated transepithelial (basal to apical) transport of 125I- by up to 90%. The inhibitory effect was noticed already after 8 h and was further pronounced after 1-4 d, depending on the AM concentration. The intracellularly accumulated 125I- was reduced by perchlorate but not AM, and quantitative real-time RT-PCR revealed no change in the NIS expression in AM-treated cells. Blocking of cAMP degradation with 3-isobutyl-1-methylxanthine or withdrawal of AM reversed AM-induced changes in electrolyte transport but were unable to recover the suppressed 125I- transport. The iodine-free AM analog dronedarone also inhibited 125I- transport to the same extent as AM. The findings indicate that AM blocks thyroidal iodide uptake by reducing the iodide permeability of the apical plasma membrane of the thyroid epithelial cells. The effect is iodine independent and long-lasting and does not involve impaired function of NIS or the TSH receptor/cAMP signaling pathway.

Amiodarone↗
PubMed2006

Effect of lifelong iodine supplementation on thyroid 131-I uptake: a decrease in uptake in euthyroid but not hyperthyroid individuals compared to observations 50 years ago.

BACKGROUND: In Sweden, iodine has been added to table salt (10 mg/kg) since 1936; this amount was increased in 1966 to 50 mg/kg. OBJECTIVE: To investigate a euthyroid Swedish population (n = 44, 60-65 years) with its entire lifespan with iodine supplementation as for 24-h 131-I uptake (24 h IU) and thyroid nodularity (thyroid scintigraphy). To compare the euthyroid 24 h IU with uptake of thyrotoxic individuals, and with observations from 1955. METHODS: The 24 h IU was used in euthyroid individuals after oral administration of 0.1 MBq/2.7 microCi radioiodine and imaging of the thyroid gland was carried out using 99mTc-pertechnetate. RESULTS: In 1999-2000, the mean 24 h IU in the euthyroid individuals was 21% (range 11-33%) and the normal (central 95%) reference interval was 14-30%. Scintigraphy suggested multinodular goitre in three euthyroid individuals. In Graves' patients (n = 53, 50-65 years), the mean 24 h IU was 61% (range 29-89%). In 1955, the 24 h IU in euthyroid individuals was higher (38%, range 10-70%), while hyperthyroid patients had uptake values similar to those recorded in the present investigation (mean 62%, range 40-90%). CONCLUSIONS: The population sample studied had to be small for ethical reasons. We conclude that the reference interval for 24 h IU is 14-30% in this population that had spent its entire lifespan with iodine supplementation. This is lower than that recorded in a Swedish euthyroid population half a century ago having had low-grade table-salt iodine supplementation for 20 years. Values for hyperthyroid patients, however, do not appear to have been affected likewise.

Aged↗
PubMed2006

Determination of intrathyroidal iodine by X-ray fluorescence analysis in 60- to 65-year olds living in an iodine-sufficient area.

OBJECTIVES: X-ray fluorescence (XRF) is a non-invasive method for determining the iodine content of the thyroid gland in vivo. In spite of the obvious clinical value of such a method in situations of iodine deficiency or iodine overload, the method has not so far been widely used. The objective was to investigate the applicability of the XRF method in a larger number of subjects. DESIGN AND SUBJECTS: The study comprised 37 individuals, aged 60-65 years, who had spent their entire life with iodine supplementation through iodinated table salt. Individuals with (previous) thyroid disease were excluded. The individual thyroid function had previously been evaluated by measurements of thyroid-related hormones, thyroid volume and 131-Iodine (131I) uptake which indicated a sufficient iodine intake of the population in the area. Iodine in the right thyroid lobe in each subject was examined using XRF. RESULTS: The mean thyroid iodine concentration was 0.4 mg mL(-1), corresponding to a mean total iodine content of 5.2 mg (range 0.9-20.2). There was a pronounced difference between individuals. No correlation was found between iodine concentration and 131I uptake or thyroid volume. Neither was iodine content and 131I uptake correlated. CONCLUSIONS: In a population living under iodine-sufficient conditions, a large variation of iodine stored in the thyroid is compatible with euthyroidism. Determination of the iodine pool by XRF investigation is feasible in a clinical setting and the method offers a unique possibility to study the intrathyroidal iodine pool in subjects with thyroid disease. The low radiation dose enables the use of the method in pregnant women and also in young individuals.

Aged↗
PubMed2004

10-year follow-up of onlay bone grafts and implants in severely resorbed maxillae.

Thirty patients with extremely resorbed maxillae had reconstructive bone grafts from the ala iliaca and endosseous implants in a one-stage procedure. The first ten patients constituted a development group and the following 20 patients a routine group. The marginal bone level and implants success rate was evaluated in a prospective long-term follow-up for a minimum of 10 years (10-13 years). Clinical and radiographic examinations were performed at 6 months and then annually up to 5 years. The final examinations were performed at the 10-year follow-up. The bridges were removed at every clinical examination. Marginal bone loss was seen up to the 3-year examination, where it averaged 4.6 mm in the routine group. Between the 3- and 10-year follow-up no significant change was registered. The initial bone loss was probably due to the design of the 3.6 mm conical unthreaded marginal part of the implant. The implant success rate was 83.1% in the routine group. Failures mostly occurred during the first 2 years (14 out of 20). A substantial amount of bone can be gained in patients with extremely resorbed maxillae, when treated with bone graft according to the procedure described in this study.

Adult↗
PubMed2004

Urinary iodine and thyroid volume in a Swedish population.

OBJECTIVE: To evaluate the present efficacy of an iodine supplementation programme working in Sweden since 1936 by studying the iodine excretion in urine and determining the thyroid volume in a population in a semi-rural community. DESIGN: A cross-sectional population screening comprising three age groups with randomly selected individuals: group 1 (children): 7-9 years, n = 61 (invited 70); group 2 (teenagers): 15-17 years, n = 61 (invited 63), and group 3 (adults): 60-65 years; n = 57 (invited 73). MAIN MEASUREMENTS: Urinary iodine was measured spectrophotometrically; thyroid volume by ultrasonography. RESULTS: The median values for urinary iodine concentration in the three age groups were 194 microg L(-1), 246 microg L(-1) and 190 microg L(-1), respectively, indicating an adequate iodine intake. In the 7-9 year olds, the median value of the thyroid volume was 4.7 mL, which coincides with the recently established upper limit of normal children of that age, 4.0-4.8 mL (ICCIDD, International Council for control iodine deficiency disorders). One eight-year-old boy had a pronounced goiter. Four teenagers and one adult were found to have an enlarged thyroid gland according to earlier established reference volumes (15 years >16 mL; adults > 25 mL). CONCLUSION: We conclude that the iodine intake in our region is sufficient in age groups ranging from young children to pre-retirement adults.

Adolescent↗
PubMed2002

Bone graft remodelling and implant success rate in the treatment of the severely resorbed maxilla: a 5-year longitudinal study.

A total of 30 patients, 10 in a developmental group and 20 in a routine group, with extremely resorbed maxillae were treated with bone grafting from the hip and implant placement in a one-stage procedure. All patients were followed for a minimum of 5 years and were examined regarding the long-term success rate of the implants and marginal bone level. The implant success rate was 74.6% for the whole patient group and 85.8% for the routine group, after 5 years. The marginal bone along the implant surface decreased continuously, up to 3 years and thereafter the bone level stabilized. In the routine group, changes in bone graft dimensions over time were also evaluated by computerized tomography. The mean height of the bone graft postoperatively at all implant sites was 8.3 mm. The total mean bone height, including bone graft and residual alveolar crest, was 12.4 mm. After 5 years the total bone height had decreased to a mean of 10 mm. The mean width of the bone graft was 12 mm postoperatively and 8.7 mm at the 5-year examination. A substantial amount of bone can be gained in patients with extremely resorbed maxillae, when treated with bone graft according to the procedure described in this study.

Adult↗
PubMed2001

Implant versus tooth-implant supported prostheses in the posterior maxilla: a 2-year report.

When implants are used for restoration of a jaw with a residual dentition, the possibility of combining implants with natural abutments may be considered. In a longitudinal comparative study, 26 patients (15 women & 11 men, age 49-84 years) with residual anterior dentitions were treated with two different designs of fixed partial dentures bilaterally in the posterior maxilla. On one side the reconstruction was supported by implants only, while on the contralateral side an implant and a tooth in combination were used. The patients were followed at intervals of 3, 6, 12 and 24 months after loading of the implants. 95 implants were placed, of which 11 non-loaded. A total of 10 implants failed, 7 prior to loading and three within the first three months of service (88.0+/-SE 6.7% cumulative survival for tested implants after two years' follow-up). There was no difference in failure rate for the implants in the two different prosthesis designs. The total mean loss of marginal bone height close to the implants was within acceptable standards, but was more pronounced at the implants not combined with teeth. The results indicate a correlation between the prosthesis design and the loss of marginal bone.

Aged↗
PubMed2001

Screening for thyroid disease of 15-17-year-old schoolchildren in an area with normal iodine intake.

OBJECTIVE: The prevalence of thyroid disease in Swedish schoolchildren is today insufficiently known. The aim of the study was therefore to determine the prevalence of abnormal thyroid function and thyroid autoimmunity in teen-age schoolchildren and to compare the findings with a healthy control group of 60-65-year-old inhabitants from the same community. SETTING: A semirural community of approximately 15,000 inhabitants. DESIGN: Cross-sectional study. MAIN OUTCOME MEASURES: Thyroid volume and serum concentrations of serum thyrotropin (TSH), total and free thyroxine (T4), total and free 3,5,3'-triiodothyronine (T3), and antithyroperoxidase antibodies (TPOAb). RESULTS: Four schoolchildren (7%, 59 screened) had elevated TPOAb concentration, three of the subjects being girls (8%). One girl with a goitre was overtly hypothyroid and one girl showed borderline-high serum TSH concentration suggesting subclinical autoimmune thyroid disease. One euthyroid boy had a goitre and high concentration of TPOAb. The serum free T3 concentration was significantly higher in 15-17-year-old than 60-65-year-old (7.4 vs. 6.4 pmol L(-1), P < 0.001). The concentrations of other thyroid hormones and of TSH in 15-17-year-old did not differ from those of the 60-65-year-old. CONCLUSIONS: We found three cases of thyroid disease in need of immediate attention or later follow-up. The prevalence of autoimmune thyroid disease was high as indicated from TPOAb measurements. Thyroid tests including TPOAb measurement should be performed on wide indications when teenagers seek medical advice. The reference intervals for teen-age children for commonly used first line tests (TSH and free T4) do not differ from those for adults.

Adolescent↗
PubMed2000

Relations between Helicobacter pylori, thyroid disease and cardiovascular risk factors in a 56-65-year-old population.

OBJECTIVE: To estimate the prevalence of and relation between Helicobacter pylori (HP) and thyroid disease in a 56-65-year-old population with cardiovascular risk factors. DESIGN: Cross-sectional study including every second individual in the age group. SETTING: The primary health care district of Mölnlycke, with about 14,000 inhabitants. PATIENTS: 170 men and 217 women aged between 56 and 65 years. MAIN OUTCOME MEASURES: Anthropometric (body mass index (BMI), waist/hip ratio (WHR)) and blood pressure measurements, biochemical analyses, including s-TSH, s-FT4 and HP serology. RESULTS: There was a high prevalence of metabolic risk factors in this pre-retirement group of individuals. The prevalence of HP was 42% in both men and women. Only a significant correlation between HP and WHR was seen in men. CONCLUSIONS: No reason could be found for including analysis of HP and thyroid tests in screening programmes for cardiovascular risk factors in men and women.

Age Distribution↗
PubMed1999

[How reliable is the laboratory? Increased needs of patient-related quality assurance].

Recent developments in medical care and research involve the increased use of immunochemical assays for hormones, tumour markers, vitamins and drugs. External quality assurance programmes using pooled human sera usually fail to detect analytical interference due to substances (e.g. anti-immunoglobulin or anti-ligand antibodies) present in individual serum specimens. The article reports on experience gained during a three-year period when specimens from individual patients attending a thyroid unit were distributed to hospital laboratories in Sweden for analysis. Specimen selection criteria were based on contradictory findings at the initial clinical or laboratory evaluation. The programme has given rise to the formation of a network of the laboratories involved, under the co-ordination of EQUALIS (External quality assurance in laboratory medicine in Sweden).

Antibodies↗