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Biomedical subjects

P H Petersen

Publications and source records attributed to P H Petersen.

14 recordsLinked to original sources
PubMed1992

Serum lactate dehydrogenase isoenzyme 1 activity in patients with testicular germ cell tumors correlates with the total number of copies of the short arm of chromosome 12 in the tumor.

The aim of our study was to assess the relationship between the serum lactate dehydrogenase isoenzyme 1 (S-LDH-1) activity in patients with testicular germ cell tumors and the number of copies of the short arm of chromosome 12 (12p) present in tumor. Twenty-seven adult patients with measurable tumor lesions were studied. Twenty-five had three or more copies of chromosome 12 per cell in the tumors. Nineteen had one or more copies of a specific chromosomal abnormality, an isochromosome of the short arm of chromosome 12, i(12p). Fourteen had increased S-LDH-1 levels. S-LDH-1 activity correlated significantly with the product of total tumor volume and the total number of copies of the short arm of chromosome 12 present per cell (total tumor 12p). We conclude that the total number of copies of the short arm of chromosome 12 in the tumors is most probably a factor contributing to the LDH-1 activity released from the tumors.

Adult↗
PubMed1992

Serum lactate dehydrogenase isoenzyme 1 and tumour volume are indicators of response to treatment and predictors of prognosis in metastatic testicular germ cell tumours.

44 patients with metastatic testicular germ cell tumours treated with cisplatin-based chemotherapy were evaluated for prognostic implications of clinical characteristics. 22 obtained complete remission by the initial chemotherapy, and 30 are disease-free. S-LDH-1 had an overall predictive value regarding the response of 80%, S-LDH of 64%, S-AFP of 62%, and S-hCG of 62%. In multivariate analysis regarding response, only tumour volume classified according to the Royal Marsden system (P = 0.0036) and S-LDH-1 (P = 0.0069) yielded information. Regarding survival, S-LDH-1 (P = 0.0141) and an estimate of total tumour mass (P = 0.0171) had most impact with additional information from S-hCG only (P = 0.0536). We conclude that S-LDH-1 may be used as a tumour marker in addition to S-hCG and S-AFP in patients with metastatic testicular germ cell tumour.

Adolescent↗
PubMed1992

Reference intervals based on hospitalized 'healthy' patients and medical students in relation to analytical bias for serum potassium.

The reliability of reference intervals for measurements of serum (S)-potassium in Danish hospital laboratories was investigated (i) by estimation of reference interval based on two different, healthy subpopulations and (ii) by comparison of reference intervals for S-potassium with analytical bias in each of 52 Danish laboratories. (i) The reference values from 227 hospitalized 'healthy' patients were obtained during the period 1979 to 1987 from the first-drawn serum specimen from the hospitalized patients, who were later discharged from the hospital without a diagnosis. The estimated 0.95 reference interval was 3.34 to 4.52 mmol l-1. The other reference sample group consisted of 314 medical students from whom blood was collected in the period from 1983 to 1987. Here the estimated reference interval was from 3.44 to 4.53 mmol l-1. The concentration values from both reference sample groups were corrected for analytical bias (+0.05 mmol l-1). (ii) The 52 Danish laboratories revealed a considerable variability in reference intervals which, regarding the lower reference limit, ranged from 3.2 to 3.7 mmol l-1 in strong contrast to the analytical bias (ranging from -0.08 to +0.15 mmol l-1) in 50 laboratories (two outliers). There was no relationship between lower reference limit and analytical bias in the individual laboratories. It is concluded that analytical performance allows for more uniform (even common) reference intervals throughout the Danish and perhaps Nordic hospital laboratories.

Adolescent↗
PubMed1992

Lack of indication of myocardial cell damage after myocardial ischaemia in patients with severe stable angina.

To evaluate myocardial cell damage in relation to spontaneous and exercise-induced ischaemia, release of myoglobin, creatine kinase (CK) and its isoenzyme MB (CK-MB) into the serum was estimated in 10 patients with severe stable angina. All patients had a positive exercise test, significant stenosis of one or more of the main coronary arteries and more than five ischaemic attacks per week. ST-segment monitoring was performed for 36 h. During the last 24 h of that period (period A) serial blood samples were analysed for myoglobin, CK and CK-MB using sensitive assays. Three days later (period B) the patients performed an exercise test at 0815 h, with ST-segment monitoring and blood sampling carried out as described for period A. During period A, 47 ischaemic episodes (100% silent) with a total duration of 599 min were noted in four patients. Forty-seven ischaemic episodes (94% silent) with a total duration of 804 min, were observed in seven patients during period B. Release of myoglobin, CK, and CK-MB did not increase in relation either to spontaneous or exercise-induced ischaemia. Thus even frequent and prolonged episodes of transient myocardial ischaemia (symptomatic or asymptomatic) in patients with severe stable angina pectoris does not seem to cause irreversible myocardial damage.

Adult↗
PubMed1992

Analytical goal-setting for monitoring patients when two analytical methods are used.

Serial results from an individual are often obtained using more than one method. Results should be transferable over time and locale. Every method has inherent analytical error, and goals are required to delineate the maximum allowable random (imprecision) and systematic (inaccuracy, bias) errors to facilitate optimal patient care. Based on Harris's proposal [Am J Clin Pathol 1979;72:374-82] that desirable imprecision should be less than or equal to one-half the within-subject biological variation, if the methods have negligible imprecision, then the maximum allowable bias between two methods used for monitoring is one-third of the within-subject biological variation. A more general model has been developed that relates the analytical imprecisions of two methods, and the bias between them, to biological variation. Applying the general formula derived in specific clinical monitoring situations in which a known change in serial results (occurring at a stated probability) stimulates clinical action allows goals for the imprecisions of the two methods and allows the difference in bias between them to be determined quantitatively.

Bias↗
PubMed1979

Variations in plasma protein concentrations in individuals with ulcerative colitis: analytical and biological factors.

Eight plasma proteins were determined in specimens taken every second day during a 14 day period from eleven patients with acute ulcerative colitis. The intra-individual variations in the concentrations of albumin, orosomucoid, haptoglobin, IgG, IgA, IgM and complement factors C3 and C4 were larger than expected in normal persons. A two-way analysis of variance was applied to the normalized protein values to estimate to what extent the observed variations could be explained by analytical errors and the influence of biological factors general to all proteins, such as changes in plasma volume and distribution between plasma and extravascular space. In half the non-operated patients the changes in all proteins could be explained by the above mentioned variations. The individual variations seen in the concentrations of haptoglobin, C4 and IgM occurred at random compared to the clinical state of the disease. Only the operated patients showed a more systematic sequence of protein changes.

Analysis of Variance↗
PubMed1978

Thyroglobulin of varying molecular sizes with different disappearance rates in plasma following subtotal thyroidectomy.

To investigate the possible presence of thyroglobulin (Tg of different molecular sizes in plasma, blood specimens were drawn from patients during and after surgery for thyroid adenoma. Tg was measured in all serum samples by a radioimmunoassay. Selected samples were fractionated on a sepharose CL-6B column, and the fractions were assayed for Tg antigen. In serum drawn at maximum Tg concentration, molecular weights of Tg antigen ranging from 660,000 (19S) to less than 100,000 were found. 6 h later the Tg antigen of mol. wt. less than 100,000 could not be detected, and after 3 days only 19S Tg was present. Correspondingly the plasma Tg concentration vs. time curve showed a biphasic course from which two half-lives could be estimated. For 19S Tg, ta1/2 had a mean value of 4.3 days, whereas the over-all half-life for the mixture of smaller molecules, tb1/2, had a mean value of 3.7 h. The smaller molecules also showed different antigenic reactivity in the assay indicating an altered structure of the molecules. The assumption that this might be due to lack of sialic acid would explain the faster catabolic rate.

Antigens↗
PubMed1978

Circulating immune complexes in ulcerative colitis.--II. Correlation with serum protein concentrations and complement conversion products.

Several serum proteins were quantified in twenty-two patients with active ulcerative colitis, and the findings were related to disease activity and occurrence of circulating immune complexes (IC). Conversion of C3 was significantly more frequent in the IC-positive group (eight patients) as compared to the IC-negative group (fourteen patients). Factor B was demonstrable in fifteen out of the twenty-two patients and seven out of the eight IC-positive patients had detectable levels of factor B. There was no difference between the IC-positive and the IC-negative group as regards serum concentrations of the complement factors C3, C4 and factor B, or serum orosomucoid, albumin, IgM and IgG. In contrast, the serum IgA levels tended to be reduced in the IC-positive group. C3 and factor B were significantly elevated in four patients with severe disease activity. In addition, C3, factor B and C4 concentrations showed a positive correlation to the serum orosomucoid levels. The serum concentrations of orosomucoid and albumin were inversely correlated to each other.

Adolescent↗
PubMed1976

Serum immunoglobulin M, G, and A concentration levels in Turner's syndrome compared with normal women and men.

Serum concentrations of immunoglobulin G (IgG), immunoglobulin M (IgM) and immunoglobulin A (IgA) were determined in 15 women with a lack of X chromsome material (Turner's syndrome), and compared with the immunoglobulin concentrations in normal men and women. Further, the investigation is supplemented by a comparison of normal women and the Turner group matched according to age. The serum concentrations of IgG and IgA in women with Turner's syndrome were very close to the concentration in serum from normal men, whereas the concentration of IgM was significantly lower. Compared to normal women the concentrations of IgG and IgM were significantly lower, and the concentration of IgA significantly higher in the Turner group. Whether these differences in serum immunoglobulins are determined by hormonal factors or under direct genetic control linked to the X chromosomes, is discussed.

Adolescent↗
PubMed1976

Electroimmunoassay of alpha1-antitrypsin with high precision.

A modification of the electroimmunoassay of alpha1-antitrypsin is described. A fixed amount of the antigen is removed by addition of antibody to standards and samples before elctrophoresis. By changing the dilution procedure, the whole area of the gel plate is used for measurements within a small concentration interval. The measurement range can be changed by the addition of different amounts of antibody. The precision is increased about three fold, with a coefficient of variation within series of 0.6% to 1.2% and between series of 0.6% to 0.7%. This improvement in precision can be used to increase the significance of measured differences in alpha1-antitrypsin concentrations. The possibility of obtaining the same precision by an increased number of replicate analyses by the normal electroimmunoassay is discussed.

Chemical Precipitation↗