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Biomedical subjects

J Gram

Publications and source records attributed to J Gram.

At least 37 records · Page 2Linked to original sources
PubMed2000

Tissue-type plasminogen activator and C-reactive protein in acute coronary heart disease. A nested case-control study.

OBJECTIVES: To study the importance of inflammation and fibrinolysis for evolution of ischaemic heart disease in a cohort of initially healthy subjects. DESIGN: Nested case-control study. Follow-up periods 7-15 years. SUBJECTS: Included in the study were 133 cases with coronary heart disease and 258 controls. INTERVENTIONS: None. MAIN OUTCOME MEASURES: Subjects with ischaemic heart disease identified in 1991 by the Danish National Hospital Register. Protein concentration of C-reactive protein (CRP) and tissue-type plasminogen activator (t-PA) were measured with ELISA methods in stored serum samples. RESULTS: CRP and t-PA concentrations were both significantly higher in cases than in controls (P < 0.001 and P < 0. 001). This difference between cases and controls for CRP and t-PA was present in both men (CRP: P = 0.022; t-PA: P = 0.001) and women (CRP: P = 0.013; t-PA: P = 0.005) and it was present in both the 7-9 years follow-up cohort (CRP: P = 0.014; t-PA: P = 0.001) and the 15 years follow-up cohort (CRP: P = 0.027; t-PA: P = 0.012). The best predictor of CRP was t-PA, whilst the best predictor of t-PA was triglycerides. In a logistic regression analysis model, t-PA still came out as independent predictor of coronary heart disease, whilst such a significance disappeared for CRP. With the use of ROC curves we determined that AUC for t-PA was 0.62, and for CRP 0.59, indicating that none of these two analytes has a high prognostic power in predicting future coronary events in an initially healthy population. CONCLUSION: We conclude that moderate increases in serum concentrations of CRP and t-PA are present for up to 15 years before the presence of clinical overt coronary heart disease; that a low-grade inflammation is determined by other risk factors and that t-PA is an independent risk factor for evolution of coronary heart disease.

Acute Disease↗
PubMed2000

Fibrin clot formation and lysis: basic mechanisms.

The hemostatic balance, introduced more than 40 years ago, addresses the components and reactions involved in fibrin turnover. Fibrin is placed in the core of this delicate balance. Defects in the mechanisms responsible for fibrin turnover might lead to thrombosis or bleeding, and fibrin consequently is an important substrate in the physiology of hemostasis. This review describes the components and processes involved in fibrin formation and fibrin degradation. Particular emphasis is put on the reactions involved in the conversion of fibrinogen to fibrin, the polymerization of fibrin molecules induced by coagulation factor XIII (FXIII), and the degradation of fibrinogen and fibrin mediated by plasmin and elastase. Furthermore, factors influencing fibrin structure and fibrin breakdown are addressed; in particular polymorphisms in the genes coding for fibrinogen and FXIII, but also the physical and biochemical conditions in which fibrin is formed. The past decades have produced a bulk of biochemical publications reviewing fibrin turnover and fibrin structure, and it has been shown that alterations in fibrin structure are important for the development of various disease conditions, whereas, the architecture of fibrin can be modified by certain drugs and chemical compounds. However, these topics deserve increased attention in clinical settings. Of particular importance might be more detailed clinical studies that review the influence of polymorphisms in the genes coding for the key factors involved in fibrin metabolism on the development of hemostatic diseases, but also the role of elastase-induced fibrin degradation deserves increased attention.

Antithrombins↗
PubMed2000

Plasma concentrations of blood coagulation factor VII measured by immunochemical and amidolytic methods.

Ever since the coagulant activity of blood coagulation factor VII (FVII:C) was identified as a risk indicator of cardiac death, a large number of studies have measured FVII protein concentrations in plasma. FVII protein concentrations are either measured immunologically with an ELISA method (FVII:Ag) or estimated with an amidolytic method (FVII:Am). We have investigated whether FVII:Am is a valuable alternative to FVII:Ag. FVII:Ag and FVII:Am were measured in 147 plasma samples from blood donors, patients on oral anticoagulant therapy, postmenopausal women on hormone replacement therapy, in postprandial plasma, in cold activated plasma and in FVII deficient plasma. There was a positive correlation (r=0.96) between FVII:Ag and FVII:Am with slightly but significantly higher values for FVII:Ag (FVII:Ag= 106 U/ml and FVII:Am=100 U/ml; p <0.001). A significant correlation (r=0.93) was still observed after omitting the data from patients on oral anticoagulant therapy, with mean values of 113 U/ml for FVII:Ag and 110 U/ml for FVII:Am (p < 0.01). In a linear regression analysis, the intercept (alpha=-21.50) was different from zero (p < 0.0001) and the slope (beta=1.16) was different from 1.0 (p < 0.001). Only a few points (3.1%) in a difference plot were present outside the expected 95% interval calculated from the analytical imprecision of the two methods. Therefore, we consider the amidolytic method an acceptable alternative to the ELISA method when analysing citrated plasma samples containing only enzymatically functional FVII protein, but the results cannot be directly transferred from one method to the other.

Adult↗
PubMed2000

The effect of low-dose acetylsalicylic acid on bleeding after transurethral prostatectomy--a prospective, randomized, double-blind, placebo-controlled study.

OBJECTIVE: An increase in the loss of blood after ingestion of acetylsalicylic acid (ASA) has been reported after several types of surgery, but randomized placebo-controlled studies have exclusively been performed after coronary artery bypass surgery. The reported effects of ASA on bleeding after transurethral prostatectomy (TURP) have been conflicting. We have studied the effect of low doses of ASA (150 mg) on bleeding after TURP in a prospective, randomized, double-blind, placebo-controlled trial. PATIENTS AND METHODS: Patients were randomized to receive either 150 mg ASA (n = 26) or placebo (n = 27) 10 days before surgery. The weight of resected tissue, operation time and blood loss, transfusion requirements and complications were recorded. RESULTS: There was no significant difference in the median operative blood loss between the groups (p = 0.528), but postoperatively the blood loss in the ASA group (median 284; quartiles 196-660 ml) was significantly higher than in the placebo group (median 144; quartiles 75-379 ml), (p = 0.011). No significant difference was observed between the groups regarding the amount of resected tissue (p = 0.209) or the operating time (p = 0.297). In both groups the operative blood loss was significantly related to the amount of resected tissue (p < 0.005) and the operating time (p < 0.005). No significant difference in transfusion requirements (p = 0.280), time to catheter removal (p = 0.455) and hospital stay (p = 0.820) were observed between the groups. CONCLUSION: Long-term low-dose ASA therapy is associated with a significant increase in the postoperative blood loss after TURP, and although no significant difference in transfusion requirements was observed more units of blood were used in the ASA group. We advise that ASA therapy should be withdrawn 10 days before TURP.

Aged↗
PubMed2000

Jet and ultrasonic nebulization of single chain urokinase plasminogen activator (scu-PA).

Recent studies have indicated that the deposition of intra-alveolar fibrin may play a central role in the pathogenesis of acute respiratory distress syndrome (ARDS). Our aim was to study whether the indigenous fibrinolytic agent (urokinase) normally present in the alveoli can be administered locally by nebulization in a recombinant zymogen form as single chain urokinase plasminogen activator (scu-PA). We aimed to characterize the particle size distribution, drug output, and enzymatic activity of scu-PA after nebulization with a Ventstream jet nebulizer (Medic-Aid, Bognor Regis, UK) and a Syst'AM DP-100 ultrasonic nebulizer (Pulmolink, Kent, UK). The particle size distribution was measured with a laser diffraction method and the drug output was determined by collection on filters. The amount of protein on the filters was determined with the Lowry method, and the enzymatic activity after nebulization was measured with a microtiter fibrin plate assay. The mass median diameter (MMD) of the scu-PA aerosol generated with the ultrasonic nebulizer was 3.69 (3.53-3.83) microm and with the jet nebulizer 2.96 (2.91-3.03) microm (p < 0.001). The drug output from the two nebulizers did not differ between nebulizers (p = 0.054). Fibrinolytically active scu-PA was generated with both nebulizers, but in contrast to jet nebulization, ultrasonic nebulization caused partial inactivation of scu-PA (p < 0.001). In conclusion, nebulization of scu-PA with the jet nebulizer is superior to ultrasonic nebulization in terms of particle size distribution and preservation of fibrinolytic activity.

Aerosols↗
PubMed2000

Premenopausal smoking and bone density in 2015 perimenopausal women.

The importance of cigarette smoking in relation to bone mass remains uncertain, especially in younger women. In a recent meta-analysis including 10 studies in premenopausal women no effect was seen in this age group. We used baseline data from a large national cohort study (Danish Osteoporosis Prevention Study [DOPS]) to study the cumulated effect of pre- and perimenopausal smoking on bone mineral density (BMD) measured shortly after the cessation of cyclic bleedings. Baseline observations on 2015 recently menopausal women were available. Eight hundred thirty-two women were current smokers and 285 were exsmokers. Significant negative associations of cigarette smoking coded as current, ex-, or never smoking were seen on bone mass in the lumbar spine (P = 0.012), femoral neck (P<0.001), and total body (P<0.001). Quantitatively, the differences between current smokers and never smokers were limited to 1.6, 2.9, and 1.9%, respectively. A statistical interaction was found between smoking and fat mass, indicating that women in the highest tertile of fat mass were unaffected by cigarette smoking. Serum vitamin D levels and osteocalcin were inversely related to the number of cigarettes smoked per day (r = 0.11 and P<0.001; r = 0.17 and P = 0.04), respectively. Bone alkaline phosphatase (BALP) and urinary hydroxyproline (U-OHP) were unaffected by current smoking. The average cumulated effect of premenopausal smoking on bone is small but biologically significant. Reduced body mass in smokers explains part of the negative effect on the skeleton and a complex interaction between smoking and fat mass on the skeleton is indicated. Serum levels of 25-hydroxyvitamin D (25-OHD) and osteocalcin are lower in smokers, which may effect rate of bone loss.

Alkaline Phosphatase↗
PubMed2000

Cytokines and bone loss in a 5-year longitudinal study--hormone replacement therapy suppresses serum soluble interleukin-6 receptor and increases interleukin-1-receptor antagonist: the Danish Osteoporosis Prevention Study.

The proinflammatory cytokines interleukin-1 beta (IL-1 beta) and IL-6 may play a central role in the acceleration of postmenopausal bone loss, but observational studies have led to contradictory results. Estrogen-dependent changes in the production of IL-1 receptor antagonist (IL-1ra) and the soluble IL-6 receptor (sIL-6R) potentially modify cytokine bioactivity. We therefore assessed the impact of menopause and hormone replacement therapy (HRT) on cytokines and activity modifiers in serum within a 5-year longitudinal study. One hundred sixty perimenopausal women (age 50.1 +/- 2.8 years) were randomized to HRT or no treatment. Serum IL-6 increased with age (r = 0.16; p < 0.05), but cytokines did not correlate with baseline bone mineral density (BMD). HRT led to small increases in IL-1ra (p < 0.001) and IL-6 (p < 0.05), with a decrease in sIL-6R (p < 0.01) and no change in IL-1 beta. No changes were observed in the control group. IL-1ra was inversely correlated with bone loss at the ultradistal forearm (r = 0.29; p < 0.05) and to a lesser degree at the spine (r = 0.20; p = 0.09). In addition, there was a weak positive correlation between sIL-6R and bone loss at the ultradistal forearm (r = 0.26; p < 0.05). High IL-6 levels were associated with slower bone loss (spine r = 0.31, p < 0.01) and controlling for age did not diminish this association. The percent change in sIL-6R during HRT was correlated with the bone loss at the femoral neck (r = -0.29; p < 0.01) and weakly with bone loss in the spine (r = -0.16; p = 0.17). In conclusion, serum IL-1ra and sIL-6R are influenced by HRT and are associated with the rate of bone loss in perimenopausal women.

Adult↗
PubMed2000

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↗
PubMed1999

Effects of hormone replacement therapy on hemostatic cardiovascular risk factors.

OBJECTIVES: From observational studies, there is evidence that hormone replacement therapy in postmenopausal women causes a decrease in cardiovascular events. It remains unknown, however, precisely by which mechanisms this reduction is achieved. The primary aim of this work was to study the effects of hormone replacement therapy on established hemostatic risk factors during 1-year treatment of healthy postmenopausal women. The secondary aim was to investigate whether there was any significant difference in these risk factors between hormone replacement therapy administered as a cyclic estrogen/sequential progestogen or continuous estrogen/sequential progestogen regimen. STUDY DESIGN: Sixty postmenopausal women were randomized to treatment with estradiol valerate 2 mg/day either continuously or cyclic (days 1 to 21; placebo on days 21 to 28). Both groups received cyproterone acetate 1 mg/day on days 12 to 21. Blood samples were collected before treatment and on cycle days 17 to 22 in cycles 3, 6, and 12. Thirty women with basic characteristics identical to the women included in the treatment group were included as a reference group. Blood samples were collected after 0, 6, and 12 months of observation. RESULTS: Hormone replacement therapy during 1 year caused a marginal but significant increase in plasma concentration of factor VIIc after 12 months of treatment (P <.05), a significant decrease in fibrinogen, and a significant decrease in the protein concentrations of tissue-type plasminogen activator, plasminogen activator inhibitor-1, and lipoprotein(a) after 3, 6, and 12 months of treatment (P <.05). Possible differences in the integrated response between the reference group and the hormone replacement therapy group were evaluated by comparison of the area under the curve as estimated in each individual on the basis of each analyte in the sampling periods. The area under the curve of fibrinogen was significantly lower in the hormone replacement therapy group than in the reference group (P <.03), whereas other variables did not deviate significantly between the groups. The areas under the curve did not deviate significantly between the group that received cyclic estrogen/sequential progestogen and the group that received continuous estrogen/sequential progestogen. CONCLUSIONS: One-year treatment with hormone replacement therapy influenced favorably a number of prognostic cardiovascular risk factors in healthy women. The most important effect was the lowering of fibrinogen. Furthermore, in this study the effect of hormone replacement therapy on hemostasis did not deviate between a cyclic estrogen/sequential progestogen regimen and a continuous estrogen/sequential progestogen regimen.

Cardiovascular Diseases↗
PubMed1999

Bleeding and activation of coagulation during and after transurethral prostatectomy: importance of the acute-phase response and prostate specific antigen?

OBJECTIVE: To evaluate the importance of coagulation activation in patients with benign prostatic hyperplasia, undergoing transurethral prostatic resection (TURP) and to examine whether changes in activity are related to blood loss, the circulatory entry of prostate specific antigen (PSA), operative trauma (resected tissue weight) and the inflammatory response, as assessed by C-reactive protein (CRP). PATIENTS AND METHODS: TURP was performed in 24 men and the weight of resected tissue and blood loss determined. The activation of coagulation was followed using new sensitive and specific assays, and the changes related to blood loss, the release of PSA, operative trauma and the acute-phase response. The area under the curve (AUC) for the measured quantities was used in correlation analysis. RESULTS: TURP was followed by a marked activation in coagulation. There was no correlation between the markers of coagulation and the operative blood loss, but the latter correlated with the weight of resected tissue (P=0.001). Postoperatively, the blood loss correlated with prothrombin fragment (F1+2; P=0.010), with thrombin-antithrombin complexes (TAT; P=0.024), and with the PSA concentrations (P=0.016) but not with fibrinogen. Serum concentrations of PSA increased significantly and the AUC in the operative period correlated with F1+2 (P=0.003) and TAT (P<0. 005), but postoperatively only with F1+2 (P=0.013). The weight of resected tissue correlated operatively with PSA (P=0.012) but not with the concentrations of F1+2 or TAT. Postoperatively, there was a correlation with the acute-phase proteins, CRP (P=0.005), fibrinogen (P=0.012) and with PSA (P=0.020). CONCLUSION: The operative blood loss is caused by surgical factors and the observed postoperative hypercoagulable state can be explained as a physiological response to bleeding, i.e. to secure haemostasis. The activity of coagulation was unrelated to operative trauma, but the acute-phase proteins were. The release of PSA into the circulation probably has an effect on blood coagulation.

Acute-Phase Reaction↗
PubMed1999

Protein C activation during the initial phase of experimental acute pancreatitis in the rabbit.

BACKGROUND: Disturbances of coagulation and fibrinolysis are well-known systemic effects of acute necrotising pancreatitis (ANP). The purpose of this experimental study was to evaluate the initial events in the haemostatic activation during ANP in an animal model with relevance to the human situation. METHODS: ANP was introduced in 7 rabbits by infusion of chenodeoxycholic acid in the pancreatic duct. Seven rabbits served as sham-operated controls. Serial measurements of coagulation variables (prothrombin time, activated partial thromboplastin time, FVII activity, fibrinogen, tissue factor activity), anticoagulant proteins (protein C, antithrombin) and fibrinolytic factors (tissue plasminogen activator, plasminogen activator inhibitor-1) were performed for 5 h. RESULTS: ANP was confirmed by elevated serum amylase, development of ascites, and histological changes of the pancreas. A moderate activation of the coagulation system was found in both study groups. A significant decrease in protein C concentration from 1 h after the induction of ANP was found, whereas the response of antithrombin and the inhibition of the fibrinolytic system were similar in the 2 study groups. Microthrombosis of the lungs or kidneys was found in 2 rabbits with ANP. CONCLUSION: An immediate activation of protein C is a specific characteristic of the haemostatic activation in ANP in rabbits. This activation has not been described previously and the possible therapeutic implications ought to be studied.

Animals↗
PubMed1999

DNA-polymorphisms and plasma levels of vascular disease risk factors in Greenland Inuit--is there a relation with the low risk of cardiovascular disease in the Inuit?

Greenland Inuit are a population with a low risk of cardiovascular disease. Recently, we stated that frequencies of potentially high risk alleles of the apolipoproteins, fibrinogen, factor V, glycoprotein IIIa and factor VII (FVII) genes have different allele frequencies in the Inuit when compared with Caucasian populations. We have extended this study and evaluated whether or not this was also true for the genetic polymorphisms of tissue-type plasminogen activator (t-PA), plasminogen activator inhibitor-1 (PAI-1), angiotensin-converting enzyme (ACE) and angiotensinogen in a group of 133 Greenland Inuit, aged 30-34 gamma. In addition, we compared the plasma levels of these factors and those of C-reactive protein (CRP) and D-Dimer in Inuit and in Danes, comparable for age and gender. Frequencies (f) were assessed of the alleles that are known as the potential high risk alleles in Caucasians. In the Inuit, the f(insertion allele) of the t-PA intron8ins311 polymorphism was 0.37 (CI 0.32-0.43), the f(4G allele) of the PAI-1 promoter polymorphism was 0.88 (CI 0.83-0.91), the f(deletion allele) of the ACE intron16ins287 polymorphism was 0.40 (CI 0.33-0.47) and the f(M-allele) of the angiotensinogen M/T353 polymorphism was 0.30(CI 0.25-0.38). As for fibrinogen and FVII polymorphisms, these frequencies are all significantly different from what is reported for Caucasian populations. In the Inuit, plasma levels of fibrinogen and D-Dimer were higher than in the Danes, the PAI-1 levels were lower and FVII, t-PA and CRP levels were comparable. The observed allele frequencies of the polymorphisms of t-PA, fibrinogen, FVII, ACE, angiotensinogen and the plasma levels of PAI-1 and D-Dimer were in accordance with the low CVD risk in the Inuit, considering the observed associations between these measures and CVD risk in Caucasian populations, but for other measures this was not the case (allele frequencies of the PAI-1 polymorphism, and plasma levels of fibrinogen, FVII and t-PA). In conclusion there are clear differences in genetic background and plasma levels of risk factors in Greenland Inuit compared with Caucasian populations, and these differences were sometimes, but not always, in accordance with the observed low cardiovascular disease risk of the Inuit population.

Adult↗
PubMed1999

Longevity is independent of common variations in genes associated with cardiovascular risk.

Do extremely old persons have a genetically favourable profile which has protected them from cardiovascular death? We have tried to answer this question by measuring DNA polymorphisms of selected cardiovascular risk indicators [factor VII, FVII (R/Q353, intron 7 (37bp)n, and -323ins10), beta fibrinogen (-455G/A), plasminogen activator inhibitor type 1, PAI-1 (-675(4G/5G)), tissue plasminogen activator, t-PA (intron 8 ins311), platelet receptor glycoprotein IIb/IIIa, GPIIb/IIIa (L/P33), prothrombin (20210G/A), methylene tetrahydrofolate reductase, MTHFR (A/V114), angiotensin converting enzyme, ACE (intron 16 ins287), and angiotensinogen (M/T235)]. Blood was collected from 187 unselected Danish centenarians, and 201 healthy Danish blood donors, aged 20-64 years (mean age 42 years). Genomic DNA was amplified using PCR and the genotype was determined by RFLP methods or allele-specific amplification followed by agarose gel electrophoresis. The frequencies of the high-risk alleles in centenarians were: for FVII R/Q353 0.91; for FVII intron 7 (37bp)n 0.67; for FVII-323 ins10 0.90; for fibrinogen 0.16; for PAI-1 0.52; for t-PA 0.59; for GPIIb/IIIa 0.16; for prothrombin 0.008; for MTHFR 0.33; for ACE 0.52; and for angiotensinogen 0.36. Comparable frequencies were observed in the blood donors. Subgroup analysis of men and women separately gave similar results. The genotype frequencies in the centenarians and the blood donors were similar for all polymorphisms, and this study suggests that common variations in genes associated with cardiovascular risk do not contribute significantly to longevity.

Adult↗
PubMed1998

Vitamin D receptor alleles do not predict bone mineral density or bone loss in Danish perimenopausal women.

A BsmI restriction enzyme polymorphism in the vitamin D receptor (VDR) gene has been reported to be associated with bone mineral density (BMD) and bone turnover. However, findings in other studies suggest the presence of considerable interaction by race, body size, and environmental factors. Therefore, we VDR BsmI genotyped 200 healthy perimenopausal Danish white women (mean age 50.8 years, mean calcium intake 900 mg/day) in a comprehensive, longitudinal, community-based population study. Bone loss was assessed by dual-energy X-ray absorptiometry (DXA) using cross-calibrated Hologic QDR-1000W and QDR-2000 densitometers, with a mean follow-up period of 4 years (range 1-5 years). Despite a distribution of genotypes similar to that of other white populations (28% bb, 49% Bb, 23% BB), VDR genotypes were not associated with lumbar or femoral baseline BMD, subsequent bone loss rates, or biochemical markers of bone metabolism (bone-specific alkaline phosphatase, urinary hydroxyproline, and serum osteocalcin). Controlling for body size, calcium intake, and serum levels of 25-hydroxyvitamin D3 [25(OH)D3] did not alter this finding. The possible existence of a threshold effect was subsequently investigated by restricting analysis to women with low serum 25(OH)D3 levels or low calcium intake. VDR BsmI genotypes showed no significant impact on bone density or bone loss in healthy Danish early postmenopausal women, even when allowance was made for calcium intake, serum 25(OH)D3, and body size.

Absorptiometry, Photon↗
PubMed1998

Effects of short-term treatment with prednisolone and calcitriol on bone and mineral metabolism in normal men.

To study the effects of treatment with glucocorticoid and calcitriol on biochemical markers of calcium and bone metabolism, 48 normal male volunteers (aged 21-54 years) were randomized to treatment for 7 days with either (A) prednisolone, 10 mg twice daily, (B) prednisolone, 10 mg twice daily, and calcitriol, 1 microg twice daily, (C) calcitriol 1 mg twice daily, or (D) placebo. The study period was 28 days. Renal calcium excretion increased (mean maximal increase +44.7%, p < 0.01) as well as serum parathyroid hormone (PTH) (max. +18.5%, p < 0.01) during prednisolone treatment. Concomitant treatment with calcitriol or calcitriol alone equally enhanced renal calcium excretion (max. +185.2%, p < 0.001) and decreased serum PTH (max. -43.1%, p < 0.001). Prednisolone administration was followed by prompt declines in markers of bone formation [serum osteocalcin (max. -34.7%, p < 0.001) and serum procollagen type I C-terminal propeptide (PICP) (max. -25.9%, p < 0.05)], whereas serum bone alkaline phosphatase (bone AP) remained unchanged. Calcitriol in combination with prednisolone attenuated the decrease in PICP (max. -8.9%, not significant), but it had no effect on osteocalcin (max. -40.1%, p < 0.001), and decreased bone AP (max. -22.2%, p < 0.05). Calcitriol alone increased osteocalcin (max. +37.8%, p < 0.03) and PICP (max. +26.0%, p < 0.05). Among markers of bone degradation, prednisolone suppressed serum C-terminal telopeptide of type I collagen (ICTP) (max. -28.4%, p < 0.001), but not the fasting renal excretion of hydroxyproline (OHP) and collagen type I N-terminal telopeptide (NTx). Calcitriol partially antagonized the decrease in ICTP (max. -17.2%, p < 0.001). Calcitriol alone had no effect on resorptive markers. Extraosseous matrix synthesis was suppressed by prednisolone evaluated by serum procollagen type III N-terminal propeptide (max. -30.8%, p < 0.001) and was not affected by concomitant treatment with calcitriol or calcitriol alone. In conclusion, short-term administration of prednisolone to healthy men leads to fast and protracted suppression of biochemical markers of bone formation and extraosseous connective tissue metabolism. The effect on bone was partially antagonized by simultaneous calcitriol treatment, and points toward a potential role of calcitriol in the prevention of steroid induced osteoporosis.

Adult↗
PubMed1998

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↗