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| 2. |
- Boguszewski, C L, et al.
(författare)
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22-kD growth hormone exclusion assay: a new approach to measurement of non-22-kD growth hormone isoforms in human blood.
- 1996
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Ingår i: European journal of endocrinology. - 0804-4643. ; 135:5, s. 573-82
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Tidskriftsartikel (refereegranskat)abstract
- Human growth hormone (GH) exists in a variety of isoforms. In the pituitary, the most abundant isoform is 22-kD GH (22 K GH), while other isoforms (non-22 K GH) are present in variable amounts. In human plasma, the GH heterogeneity contributes to the wide variability in GH levels measured by different immunoassays. The physiological role of the non-22 K GH isoforms is poorly understood, but they may represent a spectrum of agonists or antagonists of the GH receptor. It is possible that increased amounts of non-22 K GH isoforms in the circulation contribute to the growth failure observed in some short children and may be involved in the pathophysiology of acromegaly and other unrelated diseases. Currently, there is no method available to evaluate the ratio of non-22 K GH isoforms to total GH in large sets of serum samples. In this report, a novel assay procedure is described in which monomeric and dimeric isoforms of 22 K GH are removed from serum and non-22 K GH isoforms are quantitated. The 22 K GH exclusion assay (22 K GHEA) was established as a screening method to identify conditions in which the ratio of non-22 K GH isoforms to total GH in human blood is altered. A 22 K GH-specific monoclonal antibody (MCB) is used for binding to 22 K GH in serum. Magnetic beads coated with rat anti-mouse immunoglobulin G and a magnetic device are used to remove the 22K GH-MCB complexes from serum. The non-22 K GH isoforms are measured by a polyclonal antibody-based immunoradiometric assay (GH-IRMA). The assay procedure was optimized systematically by statistical experimental designs. In serum spiked with monomeric or dimeric 22 K GH, the 22 K GH extraction was efficient at GH levels up to 100 microg/l (range 96.3-100%). The intra- and interassay precision for non-22K GH levels of 3.9 microg/l were 2.6% and 8.7%, respectively, while for levels of 0.6 microg/l, which were very close to the detection limits of the assay, the coefficients were 17.0% and 21.6%, respectively. The percentage of non-22 K GH isoforms determined in serum samples from three different groups of subjects showed clearly distinctive values. The 22 K GHEA is a new method for evaluation of non-22 K GH isoforms in human blood under different physiological and pathophysiological conditions.
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- Bollen, Lise Svendsen
(författare)
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Production of polyclonal antibodies in rabbits and chickens immunised with human immunoglobulin G : A study of the utility of egg yolk antibody production as a substitute for rabbit serum antibody production
- 1997
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The utility of chicken egg yolk antibodies as an alternative to rabbit antisera was studied by comparing antibody and avidity development in immunised animals (15 rabbits and 30 chickens) during a one-year immunisation scheme. Human IgG was used as the model antigen and the efficacy of three adjuvants, Freund's Complete Adjuvant, Freund's Incomplete Adjuvant and Hunter's TiterMax, was compared. Purification procedures for egg yolk antibodies were developed, rendering the harvest and processing time for yolk and serum antibodies comparable. A majoradvantage of producing egg yolk antibodies instead of rabbit antisera is an increased productivity.Although the antibody response was found to be higher in rabbit serum than in egg yolk of chickensimmunised using identical schemes, the volumes of obtainable antibody source were ten timeshigher with egg yolk than with rabbit sera. Depending on the immunisation scheme and, inparticular, the choice of adjuvant, approximately five times more antibody can be produced per yearby a chicken than by a rabbit. Considering the cost of purchase and maintenance, rabbit antibodiesare ten times more expensive to produce. Serum antibody response in young and old chickens werecompared and no significant difference was found. The avidity of the egg yolk antibodies was foundto be similar to rabbit serum antibodies, but the qualitative properties of the immunoglobulinsdiffer. Different immunochemical and immunoelectrophoretic assays (different ELISAs, liquidphase immunosorbent assay, rocket-immunoelectrophoresis, fused-rocket-immunoelectrophoresis,line-immunoelectrophoresis, crossed-immunoelectro-phoresis, crossed-tandem-immunoelectro-phoresis, crossed-affino-immunoelectrophoresis, charge-shift-crossed-immunoelectrophoresis) weredeveloped for measuring antibody response, and analysing specificity and binding properties. TheIgG levels in developing oozytes (6 - 37 mm) were similar, and there was a significant linearcorrelation between antibody response in serum and corresponding egg yolk. From an animalwelfare point of view there are improvements associated with producing egg yolk antibodies insteadof rabbit serum antibodies.
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| 4. |
- Bosaeus, Ingvar, 1950, et al.
(författare)
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Comparison of methods to estimate body fat in growth hormone deficient adults.
- 1996
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Ingår i: Clinical endocrinology. - 0300-0664. ; 44:4, s. 395-402
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Tidskriftsartikel (refereegranskat)abstract
- All of the presently used methods for in-vivo determination of body composition have inherent methodological errors and depend on various assumptions. We have therefore compared several different methods used to measure body fat in adult GH deficiency during GH treatment.Comparison of body composition data from a two-phase trial with an initial placebo-controlled, double-blind 6-month period, followed by open treatment with GH until all patients had received GH for 12 months.Twenty-five patients with known GH deficiency entered the study. Baseline examinations were complete in 23 patients, and 22 patients (16 males, 6 females) completed all examinations after treatment.Body fat calculated from total body potassium (TBK) by whole-body 40K counting, total body water (TBW) by tritium dilution, total body nitrogen (TBN) by neutron activation, and bioelectric impedance (BIA) measurements were compared to body fat determinations by dual-energy X-ray absorptiometry (DEXA) in two-compartment and multicompartment body composition models.At baseline, DEXA fat mass agreed well at group level with measurements based on TBW or TBK alone, in a four-compartment model based on TBK and TBW, and a multicompartment model based on bone mineral (by DEXA), TBN and TBW. Body fat by BIA agreed less well. After 12 months of GH treatment, body fat decreased by all methods used. This decrease was smaller by DEXA than by the other methods. The four-compartment model based on TBK and TBW, and TBW alone, showed the best agreement with changes in DEXA fat.All methods showed a decrease of body fat with GH treatment, but variation between methods was considerable.
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| 6. |
- Johannsson, Gudmundur, 1960, et al.
(författare)
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Effects of 1 year of growth hormone therapy on serum lipoprotein levels in growth hormone-deficient adults. Influence of gender and Apo(a) and ApoE phenotypes.
- 1995
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Ingår i: Arteriosclerosis, thrombosis, and vascular biology. - 1079-5642. ; 15:12, s. 2142-50
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Tidskriftsartikel (refereegranskat)abstract
- We investigated the influence of gender and apoE and apo(a) phenotypes as well as the effect of the metabolic effects of growth hormone (GH) on the effect of GH therapy on serum lipoprotein concentrations in GH-deficient (GHD) adults. Forty-four consecutive patients, 30 men and 14 women aged 46.5 (range, 19 to 76) years with GHD due mainly to pituitary tumors, were treated with recombinant human GH for 12 months. Serum concentrations of lipoproteins, insulin, thyroxine, and insulin-like growth factor-I were determined, body composition was assessed by bioelectrical impedance, and apo(a) and apoE phenotypes were analyzed. Lipoprotein(a) [Lp(a)] concentrations in the GHD subjects were compared with a gender- and apo(a) phenotype-matched control group. After 12 months of GH treatment, the total cholesterol, LDL cholesterol, and apoB concentrations decreased, the HDL cholesterol and apoE concentrations increased, and the apoA-I and triglyceride concentrations were unchanged. Before treatment, the Lp(a) concentration was similar to that in the control group. However, after 12 months of treatment, the Lp(a) concentration had increased by 44% and 101% above baseline and the control group, respectively. Men and women responded differently to GH, with a more marked increase in Lp(a) concentration and fat-free mass and a more pronounced decrease in body-fat mass in men. Apo(a) phenotypes had no major influence on the effect of GH therapy. The only significant difference between apoE phenotypes was a higher baseline Lp(a) concentration among apoE4 heterozygotes.(ABSTRACT TRUNCATED AT 250 WORDS)
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| 7. |
- Johansson, A, et al.
(författare)
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Epitope specificity of monoclonal anticytokeratin antibody TS1
- 1999
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Ingår i: Cancer Res 1999;59:45-51.
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Tidskriftsartikel (refereegranskat)abstract
- Due to their abundance in epithelial cells and deposition in necrotic regions intratumorally, cytokeratins (CKs) have been established as valuable targets for both radioimmunolocalization and radioimmunotherapy. The target epitope for the monoclonal anti-CK8 antibody, TS1, used for both experimental radioimmunolocalization and radioimmunotherapy, was determined by means of synthesis of 96 overlapping peptides that covered the entire CK8 molecule. A highly conserved peptide sequence, spanning amino acids (aa) 343357 and covering the discontinuous epitope in the helical 2B domain, was identified. The epitope retains its helical structure, as shown with circular dichroism spectroscopy, although the length of the peptide (i.e., >20 aa) is crucial for maintenance of immunoreactivity. To determine which aa residues are crucial for binding to the monoclonal antibody, alanine scanning was performed on a 26-mer covering aa 340365, with the sequence RGELAIKDANAKLSELEAALQRAKQ. The 26 modified peptides were evaluated using ELISA and BIAcore technology. The uniqueness of this epitope has been established by data base sequence comparisons
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| 9. |
- Oscarsson, J, et al.
(författare)
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Diurnal variation in serum insulin-like growth factor (IGF)-I and IGF binding protein-3 concentrations during daily subcutaneous injections of recombinant human growth hormone in GH-deficient adults.
- 1997
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Ingår i: Clinical endocrinology. - 0300-0664. ; 46:1, s. 63-8
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Tidskriftsartikel (refereegranskat)abstract
- Whereas there seems to be little, if any, circadian variation in circulating concentrations of IGF-I and IGFBP-3 in healthy subjects, there are conflicting reports on this issue in GH-deficient patients treated with GH as a daily subcutaneous injection. We have therefore investigated the 24-hour serum profiles of IGF-I and IGFBP-3 concentrations after one week and more than one year of GH treatment.Eleven subjects, with adult onset GH deficiency mainly caused by pituitary adenomas were included in the study.In an open study, six subjects (three women and three men; age (+/-SEM) 41.2 +/- 3.9 years) were investigated after one week of GH therapy and five subjects (three women and two men; age (+/-SEM) 61.4 +/- 3.3 years) were investigated after 13-40 months of GH therapy. The GH injections were given at 2000 h. The subjects were hospitalized for 24-hour blood sampling at 1-hour intervals and serum concentrations of GH, IGF-I and IGFBP-3 were determined.There was a significant diurnal variation in serum IGF-I and IGFBP-3 concentrations both in the subjects who had received GH for one week and in those who had received GH treatment for more than one year. The serum concentrations of IGF-I and IGFBP-3 were highest in the morning and lowest during night-time and early morning. The molar IGF-I/IGFBP-3 ratio varied significantly with time in both groups of patients in a similar way as IGF-I and IGFBP-3 indicating a more pronounced variation in IGF-I compared with IGFBP-3 in response to the GH therapy.Significant diurnal variations in serum IGF-I and IGFBP-3 concentrations occur after one week and more than one year of GH treatment with daily subcutaneous injections. The results indicate that the free fraction of IGF-I may exhibit a diurnal variation.
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