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Biomedical subjects

F B Pedersen

Publications and source records attributed to F B Pedersen.

At least 19 recordsLinked to original sources

Changes in cardiac muscle mass and function in hemodialysis patients during growth hormone treatment.

BACKGROUND: Adult patients with chronic renal failure (CRF) often show symptoms as fatigue, wasting, and reduced working capacity with concomitant findings of reduced cardiac performance and muscle mass. This state may in part be caused by an imbalance in the somatostatin/somatomedine axis resulting in increased catabolism. During an attempt to correct this catabolic state by administration of exogenous growth hormone, cardiac muscle mass and performance were studied. METHODS: In a double-blind, placebo-controlled 6-month study comprising 20 adult enfeebled hemodialysis patients, 9 patients were treated with a single daily subcutaneous injection of recombinant human growth hormone (rhGH) 4 IU/m2 and 11 with placebo injections. Left ventricular muscle mass (LVM) and ejection fraction (EF) were evaluated by echocardiography and the maximal working capacity (MWC) was measured by a bicycle exercise test performed before and after the treatment period. Supplementary electrocardiography (ECG) was performed before and after 6-month treatment. RESULTS: Median LVM increased significantly from 172 to 220 g (p = 0.03) in the rhGH-treated group, while an insignificant decrease was observed in the placebo group from 281 to 200 g (p = 0.3). The EF showed no significant changes in the two groups. MWC showed a slight, insignificant decrease in both groups. From ECG no significant ST deviations were found and no significant changes regarding B-Hb, blood pressure or pulse were observed in the two groups. Irregular heart rhythm aggravated in one patient during the first month of treatment with rhGH, but was overcome by a -blocking agent. CONCLUSION: The treatment with rhGH of adult chronic hemodialysis patients for 6 months increased the left ventricular mass significantly, but without any effect on ejection fraction or maximal working capacity. No electrocardiographic signs of ischemia were associated with the increasing muscle mass and only one patient developed symptoms that might relate to ischemia. No changes in B-Hb, blood pressure or pulse were observed during the treatment period.

Adult↗

Influence of growth hormone on whole body and regional soft tissue composition in adult patients on hemodialysis. A double-blind, randomized, placebo-controlled study.

BACKGROUND: Many adult patients in chronic hemodialysis exhibit malnourishment and muscle wasting, which in some may be due partly to blockage of the biological action of growth hormone and the somatomedines. Growth hormone (GH) promotes protein synthesis, and long-term treatment with growth hormone has induced an augmentation in lean body-mass (LBM) in normal elderly persons, in persons with GH deficiency as well as growth improvement in uremic children. The purpose of this study was to evaluate the effect of long-term GH treatment on soft tissues in hemodialyzed patients by dual-energy X-ray absorptiometry (DXA) with special regard to the improvement in lean body mass and fat mass (FM). DESIGN: The study was double-blinded, randomized, and placebo-controlled. Twenty enfeebled patients in chronic hemodialysis were treated by subcutaneous injections of biosynthetic human GH (4 IU/m2 per day) or placebo, given every evening for 6 months. Soft tissues as LBM and FM, were measured by DXA scan, and height, and weight were recorded before, and after 6 months treatment. Serum concentration of insulin-like growth factor (IGF-I) and type III collagen N-terminal propeptide (PIIINP) were analyzed at baseline and after 2, 4 and 6 months. RESULTS: Six months of GH therapy induced a total FM reduction of 3.05 +/- 0.75 kg (mean +/- SEM) (p < 0.001) (n = 9) corresponding to 25% of the total fat mass. The reduction in fat was most marked at the trunk, i.e. 1.39 +/- 0.41 kg (p < 0.001) corresponding to 40% of the total FM reduction. Total LBM increased by 3.14 +/-0.41 kg (p < 0.001) in the GH group. Regional changes for arm, truncus and leg in GH group amounted to 0.22 +/- 0.06 kg (p < 0.001), 1.64 +/- 0.37 kg (p < 0.001) and 0.51 +/- 0.06 kg (p < 0.001), respectively. In contrast, total body weight remained unchanged. Serum IGF-I increased from 199 +/- 14.8 microg/l to 527 +/- 111 microg/l (p < 0.0001) at month 6, and the serum PIIINP from 7.8 +/- 1.3/microg/l to 14.3 +/- 2.1 microg/l (p < 0.001) in the GH-treated group. In the placebo group (n = 11) there were no significant changes in FM, LBM or PIIINP while serum IGF-I decreased from 285 +/- 36 microg/l to 219 +/- 35 microg/l (p < 0.01) after 6 months treatment. CONCLUSIONS: Six months of GH therapy to patients with chronic renal failure resulted in marked changes of the soft tissue with an increase in LBM, and reduction of FM particularly at the trunk. The data imply that GH-induced changes in body composition are maintained with long-term therapy. Very few side-effects of GH treatment were observed, and no serious ones were encountered, though the dosage were 2 to 3 times higher than the one given to GH-insufficient, non-uremic persons, and the serum IGF-I concentrations during treatment equalized those seen in acromegalia. This indicates the existence of a reduced biological effect of GH and IGF-I in uremic persons.

Absorptiometry, Photon↗

Growth hormone, insulin-like growth factors and their binding proteins in adult hemodialysis patients treated with recombinant human growth hormone.

BACKGROUND: Growth deficiency and malnutrition in uremic children are often caused by malfunction of the growth hormone (GH)/insulin-like growth factor I (IGF-I) axis and can be corrected by treatment with GH. The purpose of this study was to evaluate the levels of GH, IGF-I and II and their binding proteins compared to changes in body composition in adult, enfeebled, uremic patients in chronic hemodialysis (HD), treated for 6 months with recombinant human growth hormone (rhGH). METHODS: 31 patients were included in a controlled, randomized, double-blinded study using either 4 IU/m2/day of rhGH or placebo injected subcutaneously every evening for 6 months. RESULTS: Fasting levels of GH were normal at start and increased significantly from 2.2 to 13.5 microg/l (p = 0.01) within the first 4 months of rhGH treatment. Before treatment IGF-I was at the upper limit of normal range (130 to 220 microg/l) in both groups, and it increased significantly from 213 to 348 microg/l (p = 0.01) during rhGH treatment. IGF-II was above the normal range in both groups, and remained unchanged throughout. IGFBP-1 decreased in the rhGH-treated group from 53.1 to 24.7 microg/l (p = 0.004), while IGFBP-3 increased from 5620 to 7100 microg/l (p = 0.004). The molar ratio of IGF-I/IGFBP-3 increased significantly from 14 to 25% (p = 0.01), while the ratio decreased in the placebo group (p = 0.01). During the treatment with rhGH the patients increased their lean body mass (= muscle mass) by a median of 3.18 kg (range 0.82 to 5.12 kg) (p = 0.0001) while their fat mass decreased by a median of 3.33 kg (range 0.18 to 5.82 kg) (p = 0.004). Total body mass (= weight) remained stable. No significant changes were observed in the placebo group. CONCLUSION: The baseline GH and IGF-I concentrations were normal in malnourished HD patients. When treated with rhGH in a dosage as used in growth-retarded uremic children, IGF-I increased to the levels seen in acromegalic persons. IGF-I increased more than IGFBP-3 whereby its biological activity obviously improved. This was reflected in an increased muscle mass and a decreased fat mass. The rhGH treatment was well tolerated.

Adipose Tissue↗

The effect of recombinant human growth hormone treatment on bone and mineral metabolism in haemodialysis patients.

BACKGROUND: Uraemia and chronical haemodialysis are associated with an abnormal growth hormone (GH)-insulin-like growth factor (IGF) axis which may contribute to malnutrition and renal bone disease. Short-term studies have shown a beneficial effect of treatment with recombinant human growth hormone (rhGH) on nutritional status in patients on haemodialysis. In the present study, we evaluated the effect of rhGH on bone and mineral metabolism. METHODS: Twenty chronic malnourished patients on haemodialysis took part in a double-blind, placebo controlled trial with subcutaneous injections of rhGH (4 IU/m2/day) or placebo for 6 months. RESULTS: During rhGH treatment, serum IGF-1 increased 264 +/- 52% (mean +/- SEM) (P < 0.008). There were no significant changes in biochemical markers of mineral metabolism (serum ionized calcium, phosphate and parathyroid hormone). Among markers of bone metabolism, there was a significant increase in serum procollagen type I C-terminal propeptide (maximum 155 +/- 8%, P < 0.001) and no significant changes in serum alkaline phosphatase. Bone densitometry showed a significant decrease in whole body bone mineral content (95.7 +/- 1.2%) after 6 months treatment. The effects on the proximal femur were not significant. CONCLUSION: The effects of 6 months treatment with rhGH seen in this study are best explained by a GH- or IGF-1-induced increased bone turnover. Long-term treatment in larger cohorts followed by bone densitometry and, preferentially, bone histomorphometry are needed to evaluate whether this is a beneficial effect in haemodialysis patients.

Adolescent↗

Serum concentration of the aminopropeptide of type I procollagen in patients on haemo- and peritoneal dialysis.

Using an ELISA technique, the aminopropeptide of type I procollagen (PINP) was measured in serum from patients with chronic renal failure treated with haemodialysis (HD) (n = 19) or continuous ambulatory peritoneal dialysis (CAPD) (n = 14), and compared to the commonly used bone markers. The serum concentrations for PINP, compared to healthy controls were significantly increased in both the HD-group (p < 0.00001) and the CAPD-group (p < 0.00001). In the HD-group a close correlation was found between PINP and parathyroid hormone (PTH) (R(s) = 0.745; p = 0.00026) and between PINP and total alkaline phosphatase (R(s) = 0.623; p = 0.004), but in the CAPD-group the corresponding p-values were 0.17 and 0.06 only. No significant difference was found between the HD and CAPD patients with respect to serum levels of PINP, PTH, total alkaline phosphatase, or ionized calcium. In the HD-patients, a significantly higher level of serum phosphate was found compared to in the CAPD-patients. The present study demonstrates a close correlation between PTH, total alkaline phosphatase and PINP, which indicates that PINP might be used as a marker for evaluating increased bone turnover in patients with chronic renal failure treated with haemodialysis, and perhaps also in patients treated with peritoneal dialysis, and that the ideal biochemical parameters to analyse changes in bone metabolism in these patients may be a combination of the initiating hormone (PTH) and PINP as a marker of the effect of PTH on bone metabolism.

Adolescent↗

Impact of hemodialysis on dual X-ray absorptiometry, bioelectrical impedance measurements, and anthropometry.

Dual X-ray absorptiometry (DXA) performs noninvasive assessment of bone and soft tissue with high precision. However, soft tissue algorithms assume that 73.2% of the lean body mass is water, a potential source of error in fluid retention. We evaluated DXA (model QDR-2000; Hologic Inc, Waltham, MA), bioelectrical impedance analysis (BIA), and simple anthropometry in 19 patients (9 women and 10 men, mean age 46 y) before and after hemodialysis, removing 0.9-4.3 L (x: 2.8L) of ultrafiltrate. The reduction in fat-free mass (FFM) measured by DXA was highly correlated with the ultrafiltrate, as determined by the reduction in gravimetric weight (r = 0.975, P < 0.0001; SEE: 233 g), whereas BIA was considerably less accurate in assessing FFM reductions (r = 0.66, P < 0.01; SEE: 757 g). Lumbar bone mineral density (BMD) was unaffected by dialysis, as were whole-body fat and BMD. Whole-body bone mineral content, however, was estimated to be 0.6% lower after dialysis. None of the simple anthropometric measurements correlated significantly with the reduction in FFM. In an unmodified clinical setting, DXA appears to be superior to other simple noninvasive methods for determining body composition, particularly when the emphasis is on repeated measurements.

Absorptiometry, Photon↗

What are the clinical benefits of correcting the catabolic state in haemodialysis patients?

In a double-blind, placebo-controlled trial of recombinant human growth hormone (rhGH) comprising 20 chronic enfeebled haemodialysed patients, the clinical benefit of daily growth hormone treatment for six months was evaluated. Nine patients (five male, four female) were treated with rhGH 4 i.u./m2/day and eleven with placebo (seven male, four female). Their mean age was 46.5 years (range 18-68). No difference in mean age was found between the groups. A significant increase in insulin-like growth factor I (IGF-I) was observed in the rhGH-treated group (200 to 527ng/ml, p = 0.01), while a decrease was noticed in the placebo group (285 to 219ng/ml, p = 0.02). S-GH did not change significantly in either group, and there were no differences between the two groups in terms of weight, haemoglobin, s-albumin, -urea or -creatinine, which all remained unchanged during the trial. Patients' lean body mass, as measured by DXA-scanning, increased significantly in the rhGH-treated group (43.4 to 46.7kg, p = 0.004), while no change was observed in the placebo group (44.9 to 45.2kg, p = 0.76). The changes in lean body mass between the two groups were significant, p = 0.001. Left ventricular muscle mass increased significantly (227 to 286g, p = 0.03) in the rhGH-treated group, but not in the placebo group (292 to 253g, p = 0.3). The changes in left ventricular muscle mass between the two groups were significant (p = 0.02). The maximal working capacity decreased slightly and insignificantly in both groups, when measured by bicycle ergometry. Isometric muscle contraction force and endurance did not change significantly in either group. Patients' opinion about the influence of the treatment on their general well-being and working capacity, evaluated blindly on a subjective scale, improved significantly in the rhGH-treated group (9.7 to 12.6, p = 0.02), while no change was experienced in the placebo group (9.9 to 10.7, p = 0.2). No difference was however demonstrable between the two groups (p = 0.4). Thus we conclude that adult patients in long-term haemodialysis treated with rhGH experienced an increase in their lean body mass and left ventricular muscle mass. This increase in muscle mass did not, however, improve muscle contraction force or endurance when measured objectively. The rhGH-treated patients nevertheless had a subjective feeling of a slight improvement in their general wellbeing.

Adipose Tissue↗

Changes in bone mineral content during long-term CAPD. Indication of a sex-dependent bone mineral loss.

Change in bone mineral content (BMC) was evaluated in a longitudinal trial comprising 12 women and 11 men with chronic renal disease treated with CAPD and 1-alpha-OH-D3 for 2 years. The patients served as their own controls. No patients were treated with steroids. Median age was 54 and 60 years for women and men respectively. No significant difference in 1-alpha-OH-D3 dosage or serum 1,25(OH)2D3 was found between the genders in the study period. Bone mineral content at the distal radius deteriorated significantly in the females with a median decrease of 12% over 2 years, i.e. approximately 6% per year (P < 0.001 and 95% confidence limits 8-20%). No significant change was noted in the males. There was no correlation between age and BMC change. Serum total alkaline phosphatase decreased nonsignificantly in both sexes. Total serum calcium increased significantly (P < 0.05) and serum phosphate decreased significantly (P < 0.05) in the women. Serum albumin and body weight decreased significantly in the males (P < 0.01 and P < 0.05) while no change was seen in the females. The demonstrated decrease in BMC in the female patients of approximately 6% per year exceeds the commonly observed loss of 1-2% per year in healthy women when measured with the same technique. Tentatively, the severe mineral loss in the women could indicate a sex-hormone-related disturbance in bone metabolism of uraemic females.

Adult↗

Biocompatibility studies with bicarbonate-based solutions.

During long-term peritoneal dialysis (PD) treatment, the biocompatibility of the dialysis fluid is one of the factors that determine the functional integrity of the peritoneal mesothelium and stroma, and the alertness and functional capacity of the peritoneal host defense system. In vitro studies show that conventional acidic lactate-based PD solutions (LB fluids) are detrimental to some of the more important functions of the peritoneal cell system including mesothelial and white blood cells. The main toxic components of the fluids are the high hydrogen ion content (pH = 5-5.6), high lactate concentration, and osmolality. Some toxic side effects can be omitted using bicarbonate-based fluids (BB fluids), in which lactate has been replaced by bicarbonate and the pH has been normalized (7.2-7.4). The present paper is an overview of the biocompatibility tests and studies performed using bicarbonate-based continuous ambulatory peritoneal dialysis (CAPD) fluids. While the final long-term clinical evaluation of the BB fluids is still missing, biocompatibility tests indicate that these fluids are less toxic to many cell systems than the conventional acidic LB fluids. BB fluids with a high glucose content remain cytotoxic. The BB fluids are well tolerated in animal studies. Some BB fluids increase the ultrafiltration in short-term animal studies when compared with LB fluids. The few animal studies failed to demonstrate a better preservation of the peritoneal membrane integrity by BB fluids. The difference in cell toxicity between LB and BB fluids as measured in vitro also seems detectable during the first 30 min of intraperitoneal dwell in man.

Animals↗

[Peritonitis in patients undergoing continuous ambulatory peritoneal dialysis. Evaluation of cephalothin/cephalexin monotherapy as initial treatment].

To evaluate the initial antibiotic regime of cephalothin monotherapy in the treatment of peritonitis in patients on continuous ambulatory peritoneal dialysis (CAPD), the frequency of peritonitis was registered retrospectively together with the frequency of recurrent episodes and change of antibiotic. A median frequency of 0.96 episodes per year of dialysis was found. In 24% of the episodes no microorganism was cultured. 82% of the microorganisms were gram-positive cocci, 17% gram-negative rods. The frequency of recurrent episodes was 7%. The initial antibiotic treatment with cephalothin had to be changed in 33% of the cases due to microbial resistance. In another 33% the antibiotic treatment was changed to something with a narrower spectrum. More than one third of the resistant microorganisms were methicillin-resistant coagulase-negative staphylococci. With quick and reliable microbiological diagnostic technique that makes it possible to change the antibiotic treatment early, we find cephalothin to be a suitable initial monotherapy.

Adolescent↗

Cytotoxicity testing of two CAPD dialysis fluids in a model system of quiescent fibroblasts.

Indications of some bio-incompatibility of fluids used for continuous ambulatory peritoneal dialysis (CAPD) have been found previously. We have tested cytotoxicity of an frequently used dialysis fluid, Dianeal, and a new bicarbonate-based dialysis fluid with a pH of 7.4, called 87b, in a model system of quiescent fibroblasts. The ATP level of the cells and release of lactate dehydrogenase was followed during incubation in the dialysis fluids. A marked cytotoxicity of Dianeal was found mainly due to a low pH (5.0-5.5) and to a minor degree because of the lack of potassium and glutamine. 87b was less cytotoxic but it also lacked potassium and glutamine.

Adenosine Triphosphate↗

The cytotoxicity of continuous ambulatory peritoneal dialysis solutions with different bicarbonate/lactate ratios.

Five different bicarbonate-based continuous ambulatory peritoneal dialysis (CAPD) solutions (pH: 7.0-7.4; bicarbonate: 10-27 mM; lactate: 20.8-6.7 mM) were produced in order to examine the cytotoxic effects of the different compositions. The migratory capacity of normal human polymorphonuclear (PMN) granulocytes after exposure to the solutions was used as a cytotoxicity assay. All the tested solutions reduced cellular function compared to a standard cell culture medium, but considerable differences between the solutions were observed. The optimal conditions for the PMN migration were at a pH of 7.0 and at bicarbonate and lactate concentrations of 20 mM and 12.5 mM, respectively. Bicarbonate concentrations of more than 25 mM were associated with reduced cellular function as were lactate concentrations of more than 15 mM. The most advantageous CAPD solution regarding cytotoxicity towards normal human PMN's is a combination of a lactate and bicarbonate-based solution, which has a bicarbonate concentration of approximately 20 mM, a lactate concentration of 12.5 mM, and a pH of approximately 7.2.

Bicarbonates↗

Specific opsonic activity for staphylococci in peritoneal dialysis effluent during continuous ambulatory peritoneal dialysis.

In a prospective study of intraperitoneal opsonins in 30 patients undergoing continuous ambulatory peritoneal dialysis (CAPD), the IgG concentration, the fibronectin concentration, the specific antistaphylococcal antibody level, and the opsonic activity against Staphylococcus epidermidis were measured in peritoneal dialysis effluent from the initiation of CAPD and monthly for 6 months. Significant correlation was found between the four assays, but the interindividual and intraindividual variations were considerable. No statistically significant correlation was observed between susceptibility of the patients to CAPD-related infectious peritonitis and any of the above-mentioned parameters of humoral defense. We conclude that at the present time it is not feasible to use these assays for the establishment of prognosis with regard to peritonitis in CAPD.

Adult↗

Bicarbonate is not the ultimate answer to the biocompatibility problems of CAPD solutions: a cytotoxicity test of CAPD solutions and effluents.

UNLABELLED: Human polymorphonuclear granulocytes (PMN) were tested for migration and phagocytosis after exposure to CAPD solutions and effluents sampled during the first hour of dialysis from patients treated with lactate or bicarbonate based CAPD-solutions. The effluents from the lactate based solutions (Dianeal and Lockolys) reduced the migration and enhanced the phagocytosis compared to values obtained in a standard cell culture medium. Both cell functions increased during the dialysis period. In contrast, the cell-function only changed slightly when 87b, a bicarbonate based CAPD-solution (pH = 7.4, [HCO3-) = 29mM), was employed. During the first 30 minutes, the cells performed at a higher level when exposed to the 87b effluent than when exposed to the lactate effluents. The observations further indicated that optimal conditions for PMNs are at a bicarbonate concentration of less than 20 mM and a lactate concentration of less than 15mM. IN CONCLUSION: PMN migration is reduced by both lactate and bicarbonate based CAPD solutions and effluents collected during the first hour of dialysis. The bio-compatibility of CAPD solutions may be improved by combining the lactate and bicarbonate buffering systems in a solution with a concentration of less than 20 mM of bicarbonate and less than 15 mM of lactate.

Biocompatible Materials↗

Bicarbonate- versus lactate-based CAPD fluids: a biocompatibility study in rabbits.

Previous in vitro biocompatibility studies have shown bicarbonate-based continuous ambulatory peritoneal dialysis (CAPD) fluids to be superior to those based upon lactate/acetate. To evaluate these findings in vivo, 41 rabbits were subjected to CAPD for four weeks in a randomized prospective study using either Dianeal, a commercially available dialysis fluid containing lactate, or 87b, a bicarbonate-based CAPD fluid. Ten rabbits with CAPD catheters, which were flushed with a heparin solution every 36 hours, served as controls. None of the control rabbits showed clinical or histopathological signs of peritonitis, while 8 of 20 in the Dianeal group and 6 of 21 in the 87b group contracted peritonitis. Four rabbits in the Dianeal group had to be sacrificed early due to severe peritonitis. Post mortem examinations, including scanning and light microscopy, did not reveal any macroscopic or microscopic differences among the three groups of noninfected animals. No significant distinctions between the groups could be made for body temperature, weight gain, dialysate volume, dialysate differential leukocyte count, dialysate protein content, and food intake during the course of the study. In conclusion, the present animal model did not reveal any major difference in the biocompatibility between the lactate- and the bicarbonate-based CAPD fluids.

Animals↗

Detection of neutrophil granulocytes in peritoneal dialysis effluents by means of the Cytur-test. Danish Study Group on Peritonitis in Dialysis (DASPID).

Biochemical detection of neutrophils in peritoneal effluents by Cytur-test has been advocated as a fast and reliable bedside test when peritonitis is suspected in patients on continuous ambulatory peritoneal dialysis. The Cytur-test developed a light blue colour when the neutrophil count exceeded 10(8) l-1 in the dialysis effluents, while in urine the same reaction is seen at a neutrophil concentration of 10(7) l-1. The Cytur-test was inhibited by glucose at 25 g l-1 and by albumin at 10 g l-1. However, the median (range) concentrations of glucose and albumin of 60 dialysis effluents was 1.8 g l-1 (0.9-10.6 g l-1) and 1.1 g l-1 (0.3-5.2 g l-1) respectively. Thus, presence of glucose and albumin cannot be the only reason of the reduced reactivity of the Cytur-test in dialysis effluents when compared with urine.

Adolescent↗