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Biomedical subjects

K Liewendahl

Publications and source records attributed to K Liewendahl.

At least 73 records · Page 4Linked to original sources
PubMed1987

Performance of direct equilibrium dialysis and analogue-type free thyroid hormone assays, and an immunoradiometric TSH method in patients with thyroid dysfunction.

Direct equilibrium dialysis and analogue-type radio-immunoassays for free triiodothyronine (FT3) and free thyroxine (FT4) in serum were compared in 168 subjects with various states of thyroid function. A good diagnostic efficacy for FT3 and FT4 by either type of assay was observed in hyperthyroidism. In hypothyroidism the free thyroid hormone assays, particularly the FT3 assays, performed diagnostically less well, partly because patients with mild disease were included in the study. No significant differences in the percentages of misclassifications of thyroid dysfunction patients by corresponding dialysis and analogue assays were found. We observed a good linear correlation between dialysis and analogue methods for FT3 (r = 0.98) and FT4 (r = 0.97) in this study comprising out-patients not suffering from severe non-thyroidal disease, known from earlier studies in this and other laboratories to interfere in these assays. It is concluded that analogue assays may be used on out-patients in whom severe systemic diseases are less frequent than in hospitalized patients. There are, however, other limitations to the use of analogue assays than systemic diseases. We observed two euthyroid patients with thyroxine auto-antibodies causing very high FT4 concentrations as determined by analogue assay; their dialysable FT4 concentrations were normal. We also tested a recently developed immunoradiometric serum TSH assay, which was found to perform well in primary hypo- and hyperthyroidism. Serum TSH was elevated in one patient hyperthyroid because of a TSH-producing pituitary adenoma, and within the reference limits in a patient with secondary hypothyroidism.

Adult↗
PubMed1987

Diagnostic significance of indium-111 granulocyte scintigraphy in febrile patients.

Sixty-eight patients with fever of unknown origin, 32 patients with postoperative fever, and 26 patients with therapy-resistant fever after bacteremia were investigated with [111In] granulocyte scintigraphy for the detection of abscesses. The results showed that the value of [111In]granulocyte scintigraphy in the detection of infectious foci vary in these three types of febrile conditions. The overall sensitivity and specificity were 86.5% and 87.8%, respectively. We observed, however, a relatively low predictive value of a positive result in the fever of unknown origin group (73.1%), and also a low predictive value of a negative result in the bacteremia group (66.7%). The C-reactive protein (CRP) levels in patients with a true-positive scintigram were significantly (p less than 0.001) higher than in patients with a true-negative scintigram. There was also a significant positive correlation (p less than 0.01) between the serum CRP concentration and the intensity of the granulocyte accumulations. There was no correlation between the peripheral leukocyte count or the erythrocyte sedimentation rate (ESR) and the intensity of the granulocyte uptake. Therefore CRP, but not the leukocyte count or ESR, appears useful for selecting the patients who benefit most from granulocyte scintigraphy.

Adult↗
PubMed1986

Localization of melanoma with radiolabelled monoclonal antibody fragments and iodoamphetamine.

In two melanoma patients, metastases accumulated both 99mTc-labelled monoclonal anti-tumor F(ab')2 fragments and N-isopropyl-p-(123I)-iodoamphetamine. Small metastatic deposits were localized only by labelled antibody, for which a higher target-to-nontarget ratio was observed than for radioiodoamphetamine, indicating that immunoscintigraphy may be the more sensitive method. In these two patients positive immunohistochemical staining for the antibody used was observed, whereas in a third patient, with no concentration of labelled antibody, the staining result was negative showing the specificity of the immunoscintigraphy findings. It is possible that the accumulation of radio-iodoamphetamine is due to binding to melanin but this is not certain as tissue samples from one of the two patients with positive scintigrams did not contain stainable melanin.

Adult↗
PubMed1986

Assessment of thyroxine suppression in thyroid carcinoma patients with a sensitive immunoradiometric TSH assay.

Serum TSH was determined with a sensitive radioimmunometric method (TSH IRMA) in 57 patients on suppression therapy with T4 after operation for differentiated thyroid carcinoma. When using a conventional RIA technique basal TSH was not detectable and remained so even after stimulation with TRH. With the TSH IRMA method 46 patients had a basal TSH below the detection limit (0.02 mU/l) (81%) and in seven patients the values were between 0.02 and 0.05 mU/l (12%). In 23 of these patients there was a small increment of 0.01-0.15 mU/l. In two patients the basal TSH was 0.08 and 0.09 mU/l, and the increment after TRH was less than 0.7 mU/l. In two other patients with basal values close to 0.2 mU/l the increment after TRH was more than 1.0 mU/l. An undetectable basal TSH value did not thus predict an absent response to TRH. The responses were, however, in all but two cases, so small that they could be regarded as clinically insignificant. Therefore, the authors conclude that a basal TSH of 0.1 mU/l, as measured with a TSH IRMA method with a detection limit of 0.05, is a sufficient indication of TSH suppression in carcinoma patients on T4 therapy and that further testing with the TRH-stimulation test is unnecessary.

Humans↗
PubMed1985

Free thyroxin and free triiodothyronine as measured by equilibrium dialysis and analog radioimmunoassay in serum of patients taking phenytoin and carbamazepine.

We measured free thyroxin (FT4) and free triiodothyronine (FT3) in serum of patients taking the anti-epileptic drugs phenytoin and carbamazepine, both by equilibrium dialysis procedures and analog-type radioimmunoassays. By either assay, the mean concentration of FT4 was significantly decreased in patients receiving either drug, whereas their FT3 concentrations were normal or only slightly decreased. Adding therapeutic concentrations of these drugs in vitro to control sera had a small or no incremental effect on FT4 and FT3 as measured by either method, but adding greater concentrations of the drugs in vitro markedly increased the concentrations of the free hormones. These results indicate that the main mechanism of the decrease in concentrations of free thyroid hormones in serum during therapy with anticonvulsant drugs is not the displacement of hormones from their binding to plasma proteins. We also determined, using a new and sensitive immunoradiometric assay, that patients taking carbamazepine, but not those taking phenytoin, had significantly less thyrotropin in the serum.

Adolescent↗
PubMed1984

Immunological detection of faecal occult blood in colorectal cancer.

A new two-phase test kit for faecal occult blood combining a sensitive guaiac test (Fecatwin (S)ensitive) with an immunological test for human haemoglobin (FECA-EIA) was compared with three current guaiac tests (Fecatest, Fecatwin, Haemoccult) in 19 colorectal cancer patients and 11 controls on a restricted diet. A total of 43 48 h faecal samples (30 from cancer patients and 13 from controls) were collected for quantitative determination of faecal blood loss with the 51Cr method. Qualitative testing revealed that FECA-EIA was the most sensitive test, giving one (3%) false negative test result in the 30 tests on colorectal cancer patients and no false positives in the control subjects. It was also the only test that detected low-degree tumour bleeding. Fecatest and Fecatwin S were the most sensitive guaiac tests, giving 7 and 10% false negative test results, respectively, in the 30 colorectal cancer samples, whereas Haemoccult and Fecatwin gave 23% false negative test results. For screening purposes and in order to reduce costs it is suggested that only the positive test results of the very sensitive guaiac test (Fecatwin S) should be tested with the FECA-EIA test to eliminate false positive results. With this approach the diagnostic accuracy of the new two-phase test will be about twice as good as for the Haemoccult test.

Adult↗
PubMed1984

Five guaiac-based tests for occult blood in faeces compared in vitro and in vivo.

Five guaiac-based faecal occult blood tests (Fecatest, Fecatwin Sensitive, Fecatwin, Haemoccult, Hemafecia) were compared in vitro and in vivo and the effect of time between sample application and development of the colour reaction was studied. In both type of experiments the sensitivity of Fecatest, Fecatwin Sensitive and Fecatwin was higher when the colour reaction was developed at 24-72 h than at 2 h after application of the sample but for Haemoccult and Hemafecia the sensitivity in in vivo experiments was constant or tended to decrease with time. In upper gastrointestinal bleeding false negative test results were obtained for Fecatest, Fecatwin Sensitive, Fecatwin, Haemoccult and Hemafecia in 21, 23, 38, 43 and 43%, respectively. In colorectal bleeding the corresponding percentages were 10, 10, 35, 35 and 35. Using the 51Cr-erythrocyte method, quantitative estimation of intestinal bleeding was performed in 20 patients with verified colorectal cancer and in 11 control patients. When the patient was bleeding from left hemicolon 29% of the Fecatwin, Haemoccult and Hemafecia test results were negative, 10% were negative for Fecatest and 14% for Fecatwin Sensitive. In patients with tumours in right hemicolon Fecatest and Fecatwin Sensitive were positive in all samples, whereas the other tests were negative in 10%. Experiments revealed that the proportion of false positives due to dietary factors correlated with the sensitivity of the tests.

Chromium Radioisotopes↗
PubMed1984

Bone scintigraphy and serum phosphatases in the detection and follow-up of bone metastases in prostatic cancer.

Bone scintigraphy, serum acid phosphatase activity (ACP), prostatic acid phosphatase by radioimmunoassay (PAP) and alkaline phosphatase activity (ALP) were studied in 117 consecutive patients with prostatic cancer. Serum PAP was more sensitive than ACP in indicating prostatic cancer in the 63 patients with normal bone scans: 28% had positive PAP tests and 15% positive ACP tests. In the 54 patients with bone metastases no difference in the frequency of positive PAP (84%) and ACP (85%) test was observed. Serum PAP and ACP, but not ALP, were useful for the assessment of the response to therapy particularly in patients without bone metastases. In the follow-up of patients with bone metastases the scan was more informative than any of the phosphatase assays studied.

Acid Phosphatase↗
PubMed1984

Partial peripheral resistance to thyroid hormones, a post-receptor defect?

Nuclear receptor for T3 in circulating lymphocytes and cultured fibroblasts from patients with partial resistance to thyroid hormones have in the majority of the cases a normal binding affinity and a normal maximal binding capacity. This would mean that in the majority of the cases the receptors do not show any major abnormalities and that probably the mechanism for the resistance may be sought for in postreceptor events, in the transcriptional or translational events. In a few cases there has been evidence for an abnormal receptor or for the lack of an receptor.

Cell Nucleus↗
PubMed1984

Discrepancies between serum free triiodothyronine and free thyroxin as measured by equilibrium dialysis and analog radioimmunoassay in nonthyroidal illnesses.

We determined free triiodothyronine (FT3) and free thyroxin (FT4) in serum of patients with various nonthyroidal illnesses (NTI), by both commercial analog-type radioimmunoassays (A) and new equilibrium dialysis procedures (D). The mean FT3 was significantly lower in NTI by both techniques, but the decreases were of different magnitudes. The FT3(D):FT3(A) ratio was 1.96, vs 1.11 for healthy controls. In NTI the mean FT4(D) was somewhat increased, whereas the mean FT4(A) was much lower than normal, the above ratio being 1.70, vs 0.92 for controls. We ascribe these discrepancies, at least in part, to binding of radiolabeled T3- and T4-analog tracers to serum albumin.

Adolescent↗
PubMed1984

Quantitative hippurate renography.

Effective renal plasma flow (ERPF) was determined by registration of 131I-hippurate radioactivity over the heart and calculation of the disappearance constants after fitting a three-exponential function to the measured time-activity curve. Right and left kidney ERPF was calculated both by a method of tangents and a new method of summed pulses from the time interval 1-2 min after injection of the tracer. The summed pulses method is less prone to errors and is therefore recommended for use in clinical practice. Age-dependent reference values for ERPF are reported.

Adolescent↗
PubMed1983

Improved dialysis method for free thyroxin in serum compared with five commercial radioimmunoassays in nonthyroidal illness and subjects with abnormal concentrations of thyroxin-binding globulin.

We describe a method for free thyroxin (FT4) in serum, based on radioimmunoassay of T4 in serum dialysate, FT4(D). The method is analytically accurate, sensitive, reproducible, and suitable for routine use in the clinical laboratory. We compared results by this method with those obtained with five commercial FT4 assays (Amerlex, GammaCoat, ImmoPhase, LiquiSol, Spiria) and the free T4 index (FT4I). In several of the patients with nonthyroidal illness FT4(D) was above normal and FT4 as measured with the commercial assays was subnormal. In the third trimester of pregnancy all the FT4 methods gave decreased mean values, though the decreases were of various magnitudes: FT4(D) 32%, Amerlex 44%, GammaCoat 40%, Spiria 19%, LiquiSol 16%, and ImmoPhase 13%, respectively. FT4I was significantly higher than normal during late pregnancy. In women taking oral contraceptives the mean FT4I was increased, but there was no significant effect on the results obtained with the various FT4 methods. All subjects with hereditarily high or low serum thyroxin-binding globulin had normal FT4(D) and abnormal FT4I. Amerlex, ImmoPhase, and LiquiSol misclassified some of the subjects with hereditarily abnormal thyroxin-binding globulin.

Adult↗