scholarly journals Changes in the kinetics and biopotency of luteinizing hormone in hemodialyzed men during treatment with recombinant human erythropoietin.

1994 ◽  
Vol 5 (5) ◽  
pp. 1208-1215
Author(s):  
F Schaefer ◽  
B van Kaick ◽  
J D Veldhuis ◽  
G Stein ◽  
K Schärer ◽  
...  
Keyword(s):  
Luteinizing Hormone ◽  
Half Life ◽  
Recombinant Human Erythropoietin ◽  
Cell Mass ◽  
Elimination Kinetics ◽  
Deconvolution Analysis ◽  
Human Erythropoietin ◽  
Change In Mean ◽  
Plasma Half Life

To investigate the effect of recombinant human erythropoietin (rh-EPO) on the hypothalamo-pituitary-gonadal axis in end-stage renal failure, plasma luteinizing hormone (LH) concentration release was assessed by frequent blood sampling (every 10 min), both during an 8-h baseline period and after stimulation with an iv bolus of gonadotropin-releasing hormone (GnRH). Seven adult hemodialyzed men were studied before and after partial correction of anemia by rh-EPO treatment. LH was determined by an in vitro Leydig cell bioassay (bio-LH) and a highly sensitive immunoradiometric assay. Pulsatile bio-LH secretion and clearance characteristics were assessed by multiple-parameter deconvolution analysis. Although the rh-EPO treatment did not lead to a change in average concentrations of plasma bio-LH, the mass of hormone released per secretory burst more than doubled, and the estimated bio-LH production rate increased from 8.8 +/- 2.3 to 15.6 +/- 5.2 IU/L per hour (P = 0.05). The lack of change in mean plasma bio-LH is explained by a simultaneous decrease in plasma half-life from 106 +/- 27 to 67 +/- 19 min (P < 0.02). The decrease in the plasma half-life of bio-LH was closely associated with the rise in hematocrit, suggesting an effect of the increased red blood cell mass on LH distribution space and elimination kinetics. As a consequence of the changes in hormone kinetics, the incremental amplitudes of the plasma concentration pulses of bio-LH increased from 112 to 121% of nadir levels (P < 0.05), resulting in a more distinctly pulsatile pattern of hormone signals.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Treatment of the anemia of rheumatoid arthritis with recombinant human erythropoietin: Clinical and in vitro studies

1989 ◽  
Vol 32 (5) ◽  
pp. 638-642 ◽  
Author(s):  
Robert T. Means ◽  
Nancy J. Olsen ◽  
Sanford B. Krantz ◽  
Emmanuel N. Dessypris ◽  
Stanley E. Graber ◽  
...  
Keyword(s):  
Rheumatoid Arthritis ◽  
Recombinant Human Erythropoietin ◽  
In Vitro Studies ◽  
Human Erythropoietin

scholarly journals Effect of Zinc Supplementation on Renal Anemia in 5/6-Nephrectomized Rats and a Comparison with Treatment with Recombinant Human Erythropoietin

2019 ◽  
Vol 20 (20) ◽  
pp. 4985 ◽  
Author(s):  
Hui-Lin Feng ◽  
Yen-Hua Chen ◽  
Sen-Shyong Jeng
Keyword(s):  
Bone Marrow ◽  
Recombinant Human Erythropoietin ◽  
Zinc Supplementation ◽  
Bone Marrow Cells ◽  
Human Erythropoietin ◽  
Post Surgery ◽  
Rat Bone ◽  
Marrow Cells

Anemia is a severe complication in patients with chronic kidney disease (CKD). Treatment with exogenous erythropoietin (EPO) can correct anemia in many with CKD. We produced 5/6-nephrectomized rats that became uremic and anemic at 25 days post surgery. Injection of the anemic 5/6-nephrectomized rats with 2.8 mg zinc/kg body weight raised their red blood cell (RBC) levels from approximately 85% of the control to 95% in one day and continued for 4 days. We compared the effect of ZnSO4 and recombinant human erythropoietin (rHuEPO) injections on relieving anemia in 5/6-nephrectomized rats. After three consecutive injections, both the ZnSO4 and rHuEPO groups had significantly higher RBC levels (98 ± 6% and 102 ± 6% of the control) than the saline group (90 ± 3% of the control). In vivo, zinc relieved anemia in 5/6-nephrectomized rats similar to rHuEPO. In vitro, we cultured rat bone marrow cells supplemented with ZnCl2, rHuEPO, or saline. In a 4-day suspension culture, we found that zinc induced erythropoiesis similar to rHuEPO. When rat bone marrow cells were supplement-cultured with zinc, we found that zinc stimulated the production of EPO in the culture medium and that the level of EPO produced was dependent on the concentration of zinc supplemented. The production of EPO via zinc supplementation was involved in the process of erythropoiesis.

scholarly journals Mapping of the Active Site of Recombinant Human Erythropoietin

Blood ◽  
1997 ◽  
Vol 89 (2) ◽  
pp. 493-502 ◽  
Author(s):  
Steve Elliott ◽  
Tony Lorenzini ◽  
David Chang ◽  
Jack Barzilay ◽  
Evelyne Delorme
Keyword(s):  
Receptor Binding ◽  
Recombinant Human Erythropoietin ◽  
Electrostatic Interactions ◽  
Binding Activity ◽  
Amino Acid Residues ◽  
Epo Receptor ◽  
Human Erythropoietin ◽  
Biologic Activity ◽  
Identify Amino Acid

Abstract Recombinant human erythropoietin (rHuEPO) variants have been constructed to identify amino acid residues important for biological activity. Immunoassays were used to determine the effect of each mutation on rHuEPO folding. With this strategy, we could distinguish between mutations that affected bioactivity directly and those that affected bioactivity because the mutation altered rHuEPO conformation. Four regions were found to be important for bioactivity: amino acids 11 to 15, 44 to 51, 100 to 108, and 147 to 151. EPO variants could be divided into two groups according to the differential effects on EPO receptor binding activity and in vitro biologic activity. This suggests that rHuEPO has two separate receptor binding sites. Mutations in basic residues reduced the biologic activity, whereas mutations in acidic residues did not. This suggests that electrostatic interactions between rHuEPO and the human EPO receptor may involve positive charges on rHuEPO.

Variability of pulsatile luteinizing hormone secretion in young male volunteers

1994 ◽  
Vol 131 (3) ◽  
pp. 263-272 ◽  
Author(s):  
Carl-Joachim Partsch ◽  
Sievert Abrahams ◽  
Niels Herholz ◽  
Michael Peter ◽  
Johannes D Veldhuis ◽  
...  
Keyword(s):  
Luteinizing Hormone ◽  
Half Life ◽  
Hormone Secretion ◽  
Young Male ◽  
Interpulse Interval ◽  
Luteinizing Hormone Secretion ◽  
Individual Subject ◽  
Deconvolution Analysis ◽  
Pulse Detection ◽  
Male Volunteers

Partsch C-J, Abrahams S, Herholz N, Peter M, Veldhuis JD, Sippell WG. Variability of pulsatile luteinizing hormone secretion in young male volunteers. Eur J Endocrinol 1994;131:263–72. ISSN 0804–4643 Characteristics of spontaneous pulsatile luteinizing hormone secretion were compared in ten young healthy men in three 24-h profiles obtained at intervals of 14 days and 3 months. The ages of the volunteers ranged from 19 to 25 years, and heights and weights were within normal limits. Blood samples were taken at 10-min intervals and plasma luteinizing hormone (LH) was determined in the same immunoradiometric assay using monoclonal antibodies. Conventional pulse detection was carried out with PULSAR and CLUSTER programs. In addition, a simultaneous multiple parameter DECONVOLUTION was applied. As a group, no significant differences between the three profile series were found for any of the calculated parameters of LH concentration or LH secretion. However, most parameters showed low correlation coefficients between the three study periods, suggesting that substantial individual variations might contribute to the more reliable group results. Median coefficients of variation (cv) for the individual subject ranged from 9.7% (interpulse interval and endogenous half-life) to 37.7% (mass per burst). However, the maximal individual cv observed was 78.4%. Intra-individual variability was lower than the variability between subjects for quantitative properties of LH concentration and secretion, although not significantly so for all parameters. In conventional pulse detection, the highest individual reliability was found for mean and integrated LH concentrations (median cv 10.2 and 13.7%, respectively), number of pulses per 24 h (CLUSTER, median cv 12.2%), mean pulse amplitude (PULSAR, median cv 10%) and interpulse interval (CLUSTER, median cv 9.7%). In DECONVOLUTION analysis, the endogenous LH half-life (median cv 9.7%), secretory burst amplitude (median cv 14.8%) and interburst interval (median cv 14.5%) revealed the lowest intra-individual variation. In contrast, the half-duration of a secretory episode and the mass of LH secreted per burst proved to be the least reliable measures (median cv 32.7% and 37.7%, respectively). Calculated endogenous LH production rates correlated highly (p < 0.01) across all three sessions. The relative frequencies of the LH peak amplitudes/heights and peak widths (durations) showed almost identical distribution curves for all three sampling periods. In conclusion, a high reproducibility of group results for both integrative parameters and pulse characteristics of LH concentrations and secretion were found in normal men. However, intra-individual reliability was variable and at times considerable, depending on the parameter chosen. These observations suggest caution in the interpretation of single LH profiles from individual subjects or patients unless the variation reported herein is considered. C-J Partsch, Institut für Reproduktionsmedizin, Westfälische Wilhelms-Universität, Steinfurter Straβe 107, D-48149 Münster, Germany

Combined Boric Acid and Cinchocaine Chloride Poisoning in a 12-month-old Infant: Evaluation of Haemodialysis

1988 ◽  
Vol 7 (2) ◽  
pp. 175-178 ◽  
Author(s):  
M. Egfjord ◽  
J.A. Jansen ◽  
H. Flachs ◽  
J.S. Schou
Keyword(s):  
Renal Function ◽  
Boric Acid ◽  
Half Life ◽  
Total Body Clearance ◽  
Renal Toxicity ◽  
Chloride Poisoning ◽  
Total Body ◽  
Plasma Half Life ◽  
Body Clearance

A mixture containing 3 g of boric acid and 300 mg of cinchocaine chloride prescribed due to painful dental protrusion was accidentally ingested by a 12-month-old girl. She developed violent vomiting and coughing. Irritability, tremor, seizures and a delirious reaction. She was treated with diazepam, intubated, sedated and ventilated. Her diuresis was stimulated with furosemide and fluid. Within the first 24 h she was treated with haemodialysis twice on femoral catheters. Her renal function was unaffected. In two days she fully recovered. The maximum measured levels of boric acid and cinchocaine chloride approximately 6 h after ingestion were 26 μg/ml and 71 ng/ml respectively. The plasma half-life of boric acid was 7.0 h and decreased to 3.6 and 4.4 h during the two haemodialyses. The total body clearance of boric acid increased correspondingly from 21 ml/min to 41 and 34 ml/min. The in vitro clearance of boric acid of the dialyser was later determined to be 18 ml/min. It is concluded that haemodialysis is valuable in the treatment of boric acid intoxication because it increases the elimination of the drug even in patients without any sign of renal toxicity.

Sign in / Sign up

Export Citation Format

Share Document