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Biomedical subjects

Peter Wiesli

Publications and source records attributed to Peter Wiesli.

25 records · Page 2Linked to original sources
PubMed2004

Insulin determination by specific and unspecific immunoassays in patients with insulinoma evaluated by the arterial stimulation and venous sampling test.

OBJECTIVE: The aim of this study was to compare insulin concentrations measured by a traditional radioimmunoassay (RIA) and a more specific enzyme-linked immunosorbent assay (ELISA) in blood samples obtained during the arterial stimulation and venous sampling (ASVS) test in patients with insulinoma. DESIGN: Prospective case series. METHODS: In 14 patients with an insulinoma undergoing an ASVS test, blood samples were obtained from the hepatic vein at baseline and 60 s after calcium injection into an artery supplying the tumour and a control artery (supplying pancreatic tissue without tumour). A selective arterial calcium stimulation was performed in five additional patients without evidence for an insulinoma. We measured insulin by a traditional RIA and a specific immunoassay. RESULTS: In patients with insulinoma, insulin concentrations increased between 2.3- and 24.2-fold (median 8.2-fold) when measured by RIA and between 7.3- and 59.4-fold (median 16) when measured by ELISA following calcium injection into the artery supplying the tumour. Following calcium injection into the control artery, insulin concentrations were 0.6 to 1.3 times (median 1.0) the baseline values by RIA and 0.5 to 2.5 times (median 1.1) the baseline values by ELISA. In patients without insulinoma, insulin concentrations increased following calcium stimulation between 0.7- and 2.1-fold (median 1.3-fold) when measured by RIA and between 0.6- and 4.7-fold (median 1.3-fold) when measured by ELISA. CONCLUSIONS: When insulin is measured by specific immunoassays, a higher cut-off (i.e. five- to sixfold increase) rather than the traditional criterion of a twofold increase should be used to localise an insulinoma during the ASVS test. The increase in insulin concentrations following calcium stimulation is significantly higher when insulin is measured by a specific assay compared with results obtained with traditional RIAs.

Adult↗
PubMed2003

Serum cystatin C is sensitive to small changes in thyroid function.

BACKGROUND: Serum cystatin C (CysC) is a novel marker for kidney function. The impact of mild thyroid dysfunction on CysC has never been investigated. METHODS: CysC was determined at the time of diagnosis of subclinical hypo- and hyperthyroidism, and when TSH returned into the normal range in 40 consecutive patients with mild thyroid dysfunction. RESULTS: Twenty-six patients with subclinical hypothyroidism and 14 patients with subclinical hyperthyroidism were included. In patients with subclinical hypothyroidism median (range) TSH was 7.8 (4.3-26.7) mU/l (reference 0.27-4.2) at diagnosis and decreased to 2.3 (0.36-4.0) mU/l following treatment with levothyroxine. Mean (+/-S.D.) CysC increased from 0.88+/-0.23 mg/l (reference 0.63-1.33) in the hypothyroid state to 1.01+/-0.21 mg/l when TSH normalized (p<0.001). In patients with subclinical hyperthyroidism, median TSH at diagnosis was 0.08 (0.001-0.26) mU/l and increased to 1.6 (0.28-4.0) mU/l in the euthyroid state. CysC declined from 1.04+/-0.29 mg/l at diagnosis of subclinical hyperthyroidism to 0.91+/-0.25 mg/l when TSH normalized (p<0.05). CONCLUSIONS: Mild thyroid dysfunction significantly alters CysC levels. Therefore, thyroid function has to be considered when CysC is used as a marker of kidney function.

Adolescent↗
PubMed2003

Impact of thyroid dysfunction on serum cystatin C.

BACKGROUND: Serum cystatin C (CysC) is a novel marker for kidney function that has been claimed to be superior to serum creatinine. Thyroid dysfunction may alter creatinine, which has been found to be increased in hypothyroidism and decreased in hyperthyroidism. This study was performed to evaluate whether changes in CysC and creatinine are parallel during the treatment of hypo- and hyperthyroidism, respectively. METHODS: Prospective case series of 22 consecutively referred patients with thyroid dysfunction. Creatinine and CysC were determined at the time of diagnosis of hypo- and hyperthyroidism, and when free thyroxine (fT4) returned into the normal range. Hypothyroid patients were treated with levothyroxine. Hyperthyroid patients were treated with antithyroid drugs, surgery, or radioiodine. RESULTS: Nine patients with hypothyroidism and 13 patients with hyperthyroidism were included. In patients with hypothyroidism mean fT4 (+/-SD) was 4.9 +/- 2.5 pmol/L (reference, 12 to 22) at diagnosis and increased to 16.6 +/- 3.6 pmol/L when patients were treated with levothyroxine. Creatinine decreased from 86 +/- 13 micromol/L (reference, 70 to 105) in the hypothyroid state to 76 +/- 16 micromol/L when fT4 normalized (P = 0.062), whereas CysC increased from 0.84 +/- 0.17 mg/L (reference, 0.63 to 1.33) to 1.1 +/- 0.28 mg/L (P < 0.001). In patients with hyperthyroidism, mean fT4 was 54.6 +/- 22.7 pmol/L (reference, 12 to 22) at diagnosis and decreased to 15.8 +/- 3.6 pmol/L following treatment with antithyroid drugs, thyroid surgery, or radioiodine. Creatinine increased from 67 +/- 15 micromol/L at diagnosis of hyperthyroidism to 75 +/- 9 micromol/L when fT4 normalized (P = 0.004), whereas CysC declined from 1.32 +/- 0.17 mg/L to 0.95 +/- 0.19 mg/L (P < 0.001). CONCLUSION: Thyroid dysfunction has a major impact on CysC levels. Therefore, thyroid function has to be considered when CysC is used as a marker of kidney function. In contrast to creatinine concentrations, CysC levels are lower in the hypothyroid and higher in the hyperthyroid state as compared with the euthyroid state.

Adolescent↗
PubMed2002

Roxithromycin treatment prevents progression of peripheral arterial occlusive disease in Chlamydia pneumoniae seropositive men: a randomized, double-blind, placebo-controlled trial.

BACKGROUND: Evidence has been provided that the atherosclerotic process may be associated with chronic infection with Chlamydia pneumoniae. The effect of antibiotic treatment on peripheral arterial occlusive disease has not been investigated yet. METHODS AND RESULTS: Forty C pneumoniae seropositive men suffering from peripheral arterial occlusive disease were randomly assigned to receive either roxithromycin (300 mg daily) or placebo for 28 days. During the 2.7-year follow-up, the number of invasive revascularizations per patient, the walking distance before intervention (in patients without intervention at study end), and the change of carotid plaque size were assessed. Five interventions were performed on 4 patients (20%) in the roxithromycin group, and 29 interventions were performed on 9 patients (45%) in the placebo group. Limitation of walking distance to 200 m or less was observed in 4 patients (20%) in the roxithromycin group and in 13 patients (65%) in the placebo group. The effect of macrolide treatment on the number of interventions per patient and on preinterventional walking distance was significant. Possible confounding variables such as classical vascular risk factors were excluded by multiple regression analyses. Carotid plaque areas monitored over 6 months decreased in the roxithromycin group (mean relative value, 94.4%) but remained constant in the placebo group (100.2%). Regression of carotid plaque size observed in roxithromycin-treated patients was significant for soft plaques. CONCLUSIONS: This study indicates that macrolide treatment for 1 month is effective in preventing C pneumoniae seropositive men from progression of lower limb atherosclerosis for several years.

Aged↗