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Biomedical subjects

J C Souberbielle

Publications and source records attributed to J C Souberbielle.

At least 19 recordsLinked to original sources
PubMed2002

Factors influencing the growth hormone response to growth hormone-releasing hormone in children with idiopathic growth hormone deficiency.

OBJECTIVE: To evaluate the factors influencing the growth hormone (GH) response to GH-releasing hormone (GHRH) test in idiopathic GH deficiency. METHODS: 28 patients aged 4.9 +/- 0.7 years with certain GH deficiency were given GHRH (2 microg/kg). RESULTS: The GH peak after GHRH was correlated negatively with age at evaluation (r = -0.37, p < 0.05) and body mass index (r = -0.44, p = 0.02), and positively with anterior pituitary height (r = 0.47, p = 0.02), GH peak after non-GHRH stimulation (r = 0.78, p < 0.0001) and spontaneous GH peak (r = 0.82, p = 0.007). It was lower in the patients aged >5 years than in the youngest (p = 0.04), but it was similar in the patients with and without features suggesting a hypothalamic origin. CONCLUSION: The GH response to GHRH test cannot be used to differentiate between hypothalamic and pituitary forms of idiopathic GH deficiency, probably because the GH response decreases after the first 5 years of life, whatever the origin of the deficiency.

Body Height↗
PubMed2001

Effects of growth hormone on growth factors after renal transplantation.

Growth retardation occurs frequently in renal transplanted children (RTx) and can be improved by growth hormone (GH) treatment. This study retrospectively examines the insulin-like growth factor-1 (IGF-1) and IGF binding protein (IGFBP) profile of ten growth-retarded children previously given renal allografts, after 1 year of GH treatment period. Ten prepubertal patients (nine boys and one girl) were investigated. They had a mean chronological age (CA) of 11.4 +/- 1.1 years and a mean bone age (BA) of 7.3 +/- 0.9 years. Mean height was -3.9 +/- 0.4 SD units below the mean for CA. The mean body mass index (BMI) was 16.9 +/- 0.6 and the mean inulin clearance was 36.5 +/- 4.9 ml/min/1.73 m2. Recombinant hGH was given at 4 IU/m2/day. Plasma GH, total and free IGF-1, IGFBP-2 and -3 were measured by specific radioimmunoassay (RIA). IGFBPs were characterized by SDS PAGE techniques and ligand and immunoblot analyses. Mean velocity was markedly increased (P < 0.01) after 1 year of GH therapy, expressed as SD score for BA. The range of growth response was wide. The total and free plasma IGF-1 increased (P < 0.01) by about 100% (mean values after GH therapy: 95.9 +/- 2.1 nM and 165 +/- 29 pM, respectively). Plasma IGFBP-3 concentrations increased by about 40% (mean value: 148 +/- 18 pM, P < 0.01), with a concomitant increase in both intact IGFBP-3 and its 30-kDa proteolytic fragment. There was no change in plasma IGFBP-2 concentration. Both mean values of inulin clearance and BMI were unchanged during the treatment. In view of the IGF-1/IGFBP concentration changes, there should have been an even better growth response to GH therapy in these patients. This strongly suggests IGF-1 insensitivity, probably as a result of corticosteroid therapy.

Adolescent↗
PubMed2001

High serum levels of a non-(1-84) parathyroid hormone (PTH) fragment in pediatric haemodialysis patients.

The measurement of serum intact parathyroid hormone (PTH) is routinely made in haemodialysed (HD) patients to diagnose and monitor secondary hyperparathyroidism. We measured pre- and post-dialysis serum ionized calcium (Ca2+) and PTH in 12 HD children (7 boys) aged 13.8+/-3.6 years. A group of 27 normal short-statured children served as controls. Serum PTH was assessed by a new assay (CAP) recognizing only the (1-84) molecule and an older one (Allegro) recognizing both the 1-84 and a non-(1-84) PTH equally. The concentrations obtained with the CAP assay were lower than those obtained with the Allegro assay both in controls and in HD patients. They were still lower in HD patients when expressed as multiples of the median of the control group. The Allegro/CAP ratio, was highly variable from one subject to another and was lower (P<0.0001) in controls (1.46+/-0.26) than in HD patients, both before (3.06+/-1.60) and after dialysis (2.94+/-0.65). During dialysis, Ca2+ increased significantly (P<0.0001) and PTH decreased significantly (P<0.0001) with both the CAP and the Allegro assays, but was more often normal or low with the CAP than with the Allegro assay. Although the two assays correlate well, they may provide different clinical information in some HD children which could lead to different therapeutic decisions.

Adolescent↗
PubMed2001

DHEA in bone and joint diseases.

Serum concentrations of dehydroepiandrosterone (DHEA) and its sulfate ester (sDHEA) decrease dramatically with age in parallel with the appearance of age-related health problems, leading to the suggestion that DHEA replacement therapy may be beneficial in older patients. Daily oral doses that restore sDHEA levels to the values seen in young adults are well tolerated in the short-term (6 months to 1 year) and seem to have a positive although modest beneficial effect on bone in elderly women, particularly those with low pretreatment sDHEA levels. This effect seems ascribable to both decreased bone resorption and increased bone formation, which are probably related mainly to conversion of DHEA into active sex steroids, i.e., estradiol and testosterone; this explains why there is no effect on bone in men, whose testes continue to produce testosterone throughout life. Other mechanisms of action, including an increase in insulin growth factor-1, may be operative also. DHEA cannot be recommended as a treatment for osteoporosis at present given the absence of studies evaluating possible efficacy in reducing the fracture rate and possible long-term side effects.

Administration, Oral↗
PubMed2001

Human parathyroid cell proliferation in response to calcium, NPS R-467, calcitriol and phosphate.

It remains uncertain how calcium, phosphate and calcitriol regulate parathyroid cell growth. The present study was aimed at examining possible direct effects of these modulators and of the calcimimetic NPS R-467 on parathyroid cell growth in vitro. Cell proliferation was determined by [3H]thymidine incorporation and cell cycle antigen Ki 67 expression in a parathyroid cell culture model derived from uraemic patients. The effect of NPS R-467 on parathyroid hormone (PTH) secretion and intracellular [Ca2+]i response was also examined. Increasing the [Ca2+] in the medium from 0.5 to 1.7 mM increased DNA synthesis (P < 0.005) and the number of Ki 67-positive cells (P < 0.005). However, NPS R-467 (0.01-1 microM) inhibited 3[H]thymidine incorporation by 35% in the presence of 0.5 mM [Ca2+]e. Exposure of cells to Ca2+ or NPS R-467 led to a rapid increase of intracellular Ca2+, although the pattern of increase differed. Addition of calcitriol (10-10-10-7 M) to the culture medium suppressed [3H]thymidine incorporation dose-dependently. Finally, high levels of phosphate (3.5 mM) in the medium led to a significant (P < 0.05) increase in [3H]thymidine incorporation. The observed stimulatory effect of Ca2+ in the medium in vitro appears to be at variance with the inhibitory effect of calcimimetic NPS R-467 in vitro. In an attempt to solve these apparent discrepancies, and based on the notion of a reduced calcium-sensing receptor (CaR) expression in parathyroid tissues of uraemic patients, we hypothesize that Ca2+ may regulate parathyroid cell proliferation via two different pathways, with predominant growth inhibition in cases of high CaR expression or activation, but prevailing stimulation of proliferation in cases of low CaR expression.

Aniline Compounds↗
PubMed2001

Growth hormone deficiency caused by pituitary stalk interruption in Fanconi's anemia.

Fanconi's anemia can be associated with growth retardation. We describe biologic growth hormone deficiency, isolated or associated with thyrotropin abnormality, and pituitary stalk interruption syndrome on magnetic resonance imaging of 5 patients with Fanconi's anemia. Growth hormone treatment produced catch-up growth in all cases. These findings suggest a common genetic origin.

Body Height↗
PubMed2001

Effect of type of dialysis membrane on bone in haemodialysis patients.

BACKGROUND: Uraemic bone disease is the result of a number of factors modulating bone formation and resorption in a complex manner. In the present study, the hypothesis tested was that the type of haemodialysis membrane used for renal replacement therapy might also play a role. METHODS: We conducted a prospective, open study in 24 chronic haemodialysis patients who were randomized to dialysis treatment with either cellulosic (CELL group, n=11) or polyacrylonitrile (AN-69 group, n=13) membrane for 9 months. Repeated determinations of plasma parameters reflecting bone turnover were done in all patients, and a bone biopsy in a subgroup at the start and end of study. RESULTS: At the start, mean plasma intact parathyroid hormone levels were comparable between the two groups and they did not vary significantly at 9 months of treatment. Similarly, plasma bone-specific alkaline phosphatase and osteocalcin (markers of bone formation), and cross-laps (marker of bone resorption) remained unchanged. However, plasma insulin-like growth factor-I (IGF-I) progressively decreased from 169 to 119 ng/ml in AN-69 group (P<0.01), whereas it remained unchanged in CELL group. In addition, the levels of IGF binding protein (IGFBP)-1 and IGFBP-2 were increased while the levels of IGFBP-5 were decreased in AN-69 group. In the five patients of each group who had repeat bone biopsies, histomorphometric analysis showed a decrease in osteoblast surface, osteoclast surface and osteoclast number in AN-69 group at 9 months, compared with baseline values measured at the start of the study. In contrast, all three parameters significantly increased in the CELL group at 9 months (P<0.001 for the difference between each of the three parameters). Bone formation rate decreased by 31% in the AN-69 group, but increased by 50% in CELL group. However, this latter difference was not statistically significant. Plasma interleukin (IL)-6 and soluble IL-6 receptor levels did not change in the two groups of patients who had undergone bone biopsy. CONCLUSION: Dialysis with CELL membrane was associated with increased bone turnover whereas the use of AN-69 membrane was associated with decreased bone turnover, suggesting a beneficial effect of the latter on high-turnover uraemic bone disease. However, as the number of patients with repeat bone biopsies was small, these findings need to be confirmed in a larger study. Further studies are also needed to evaluate whether or not the changes in IGF system components play a role in decreased bone cell activity in patients on dialysis using the AN-69 polyacrylonitrile membrane.

Acrylic Resins↗
PubMed2001

Vitamin D status and redefining serum parathyroid hormone reference range in the elderly.

Subclinical vitamin D insufficiency is characterized by mild secondary hyperparathyroidism and enhanced risk of osteoporotic fracture. However, although low levels of 25-hydroxyvitamin D (25OHD) are common in otherwise normal elderly people, vitamin D status has not generally been taken into account in the previously published reference values for serum PTH. We measured fasting morning serum (obtained from April through June) PTH, total calcium, albumin, phosphate, creatinine, bone markers, and 25OHD in 280 healthy subjects (140 men and 140 women), aged 60-79 yr. Serum PTH was measured by means of 2 immunoradiometric assays, the Allegro intact PTH assay (Nichols Institute Diagnostics) and the new CAP assay (Scantibodies Laboratory, Inc.). We found a high prevalence (167 of 280; 59.6%) of low 25OHD (< or =30 nmol/L) in these otherwise healthy individuals. The PTH concentrations (95% confidence interval) obtained in the whole group of 280 subjects ranged from 13-64 ng/L for the Allegro assay and from 10-44 ng/L for the CAP assay. In the subjects with a serum 25OHD concentration greater than 30 nmol/L, values for both PTH assays were lower, 10-46 and 9-34 ng/L for the Allegro and the CAP assays, respectively. By using these values as a reference range, approximately 25% of the subjects with a serum 25OHD level of 30 nmol/L or less had a high serum PTH level (whatever the assay), reflecting secondary hyperparathyroidism. This might be missed if the reference PTH values are those obtained in the entire group, as is usually done. These results strongly suggest that vitamin D status should be taken into account when establishing reference values for serum PTH in elderly subjects.

Aged↗
PubMed2001

Disorders of growth and puberty in children with non-tumoral hydrocephalus.

Hydrocephalus may cause disorders of growth and puberty. 31 patients (25 girls) with non-tumoral hydrocephalus were seen at 8.5 +/- 3.1 (SD) years for short stature (8 patients), overweight (8 patients), central early puberty (onset before 9 years, 21 patients), premature pubarche (1 patient) and/or delayed puberty (2 patients). Among the patients with short stature, 4 had meningomyelocele and one had untreated early puberty. Only 1/11 patients evaluated had growth hormone deficiency. Among the overweight patients, 5 had early puberty. The plasma leptin concentrations were positively correlated with the body mass index (r = 0.65, p < 0.01, n = 14). Free thyroxin, cortisol, prolactin and concomitant plasma and urinary osmolalities were normal in all cases evaluated, except one who had low free thyroxin. The 7 patients with early puberty and who were given gonadotropin releasing hormone analog for over 2 years had mean predicted adult height of -2.45 +/- 1.9 SD before treatment and -2.46 +/- 1.4 SD afterwards. Ventriculocisternostomy performed on 2 girls seen for delayed puberty was followed by breast development and menarche. In conclusion, in children with hydrocephalus, short stature is frequently due to meningomyelocele and rarely to GH deficiency. Central early puberty is the most frequent endocrine disorder.

Body Height↗
PubMed2000

Dehydroepiandrosterone (DHEA), DHEA sulfate, and aging: contribution of the DHEAge Study to a sociobiomedical issue.

The secretion and the blood levels of the adrenal steroid dehydroepiandrosterone (DHEA) and its sulfate ester (DHEAS) decrease profoundly with age, and the question is posed whether administration of the steroid to compensate for the decline counteracts defects associated with aging. The commercial availability of DHEA outside the regular pharmaceutical-medical network in the United States creates a real public health problem that may be resolved only by appropriate long-term clinical trials in elderly men and women. Two hundred and eighty healthy individuals (women and men 60-79 years old) were given DHEA, 50 mg, or placebo, orally, daily for a year in a double-blind, placebo-controlled study. No potentially harmful accumulation of DHEAS and active steroids was recorded. Besides the reestablishment of a "young" concentration of DHEAS, a small increase of testosterone and estradiol was noted, particularly in women, and may be involved in the significantly demonstrated physiological-clinical manifestations here reported. Bone turnover improved selectively in women >70 years old, as assessed by the dual-energy x-ray absorptiometry (DEXA) technique and the decrease of osteoclastic activity. A significant increase in most libido parameters was also found in these older women. Improvement of the skin status was observed, particularly in women, in terms of hydration, epidermal thickness, sebum production, and pigmentation. A number of biological indices confirmed the lack of harmful consequences of this 50 mg/day DHEA administration over one year, also indicating that this kind of replacement therapy normalized some effects of aging, but does not create "supermen/women" (doping).

Absorptiometry, Photon↗
PubMed2000

Adult height after growth hormone (GH) treatment for GH deficiency due to cranial irradiation.

BACKGROUND: The indications and factors affecting the growth in response to treatment with growth hormone (GH) of patients with cranial irradiation-induced GH deficiency remain unclear. PROCEDURE: The adult heights of 56 patients treated with GH (0.4-0.6 U/kg/week) as daily sc injections were analysed. They had been given 18 or 24 Grays (Gy) cranial irradiation for leukemia (group 1, 26 cases), 50 +/- 1 Gy for various tumors (group 2, 13 cases), 46 +/- 1 Gy for retinoblastoma (group 3, 8 cases), or 34 +/- 2 Gy with spinal irradiation for medulloblastoma (group 4, 9 cases). Twenty- five of these 56 patients had early puberty and were also treated with gonadotropin-releasing hormone (GnRH) analog. RESULTS: The standing (-1.0 +/- 0.2 in group 1, -0.7 +/- 0.3 in group 2, -1.1 +/- 0.3 in group 3, and -2.0 +/- 0.4 SD in group 4) and sitting (-1.8 +/- 0.2 in group 1, -0.4 +/- 0.4 in group 2, -1.2 +/- 0.4 in group 3, and -3. 4 +/-0.4 SD in group 4) adult heights were shor ter (P < 0.05 for standing and P < 0.001 for sitting heights) for group 4 than for each of the other groups. Of the 47 patients given cranial (and not craniospinal) irradiation, sitting adult height was shorter (P = 0. 02) and the difference between standing adult and target heights greater (P = 0.03) in those patients in whom puberty occurred at a normal age than in those treated with GnRH analog. Conclusion. The incomplete catch-up of growth seems to be mainly due to the reduction in sitting height of patients given spinal irradiation and in whom puberty occurred at a normal age. This suggests that GnRH analog treatment should be more widely used to treat children with early and/or rapidly progressing puberty after cranial irradiation.

Adolescent↗
PubMed2000

Differences in the capacity of several biochemical bone markers to assess high bone turnover in early menopause and response to alendronate therapy.

We measured bone mineral density (BMD), four markers of bone formation [bone alkaline phosphatase (bAP), osteocalcin (Oc), N- and C-terminal propeptide of type I procollagen (PINP and PICP respectively)] and five markers of bone resorption [serum C-terminal telopeptide of type I collagen (CTx), urinary CTx, N-terminal cross-linked telopeptide (NTx), free and total deoxypyridinoline (fDpd and tDpd respectively)] in 28 healthy premenopausal women (45.7 +/- 3.0 years), 15 early (< 7 years) healthy menopausal women (53.8 +/- 3.1 years) and 20 osteoporotic women (65.3 +/- 8.2 years). Bone markers and BMD were also measured in the osteoporotic women 4.1 +/- 0.2 and 12.6 +/- 1.2 months after the beginning of alendronate therapy (Fosamax, 10 mg/day) respectively (BMD in 16/20). We calculated the intra-individual coefficient of variation (iCV) and the least significant change (LSC) for each bone marker from a subset of 9 healthy premenopausal women (32 +/- 5 years) who had a first and a second morning void urine collection (FMV and SMV respectively) and a blood sample on 4 nonconsecutive days (mean interval 14 +/- 3 days). None of the bone markers was correlated with BMD (except p = 0.043 between serum Oc and hip BMD). All markers, except fDpd, were increased significantly in early menopausal women when compared with the premenopausal group. Serum CTx presented the highest increase at menopause (+67.8%) and identified the highest rate (11/15) of early menopausal women with bone turnover above the premenopausal range. The iCVs for bone formation markers (7.2-14.4%) were lower than those for bone resorption markers (14.6-22.3%). The iCVs obtained on FMV and SMV were not different. The decrease after 4 months of alendronate was significant for each bone marker but variable from one marker to another. Serum CTx showed the largest decrease (70.8%) and identified the highest number of biologically responding patients (change > LSC; n = 17/20). A significant change in serum CTx after 4 months of alendronate was the best predictor of a significant gain in spine BMD (i.e., > or = 27 mg/cm2) after 1 year of therapy, allowing 15 of 16 patients (94%) to be classified correctly (one false-positive). Urinary NTx/Cr was the second best predictor. Despite a moderately high iCV (20.6%), serum CTx appeared the most effective of the markers tested and could be of interest for the detection of high bone turnover and the longitudinal monitoring of alendronate therapy in the individual patient. It must be stressed that serum PINP and urinary NTx and tDpd compared very similarly with serum CTx for monitoring alendronate therapy.

Adult↗
PubMed2000

The use of insulin-like growth factor 1 reference values for the diagnosis of growth hormone deficiency in prepubertal children.

OBJECTIVE: This study was done to determine whether the use of reference values obtained in children with idiopathic short stature (ISS) improved the clinical value of serum insulin-like growth factor I (IGF-1) as a tool for diagnosing GH deficiency (GHD) in prepubertal children. PATIENTS AND METHODS: Serum IGF-1 was measured with a new IRMA kit (IGFI-RIA CT, Cis Bio, Gif sur Yvette, France) in 168 prepubertal normal children and in prepubertal children with ISS (n = 68), organic GHD due to a craniopharyngioma (oGHD, n = 15) and permanent idiopathic GHD (iGHD, n = 28). RESULTS: IGF-1 was lower (P < 0.001) in iGHD than in either ISS or oGHD and was below the fifth percentile of the normal range in 29/68 ISS (43%), 8/15 oGHD (53%) and 28/28 (100%) iGHD patients. Three oGHD (20%) and two iGHD (7%) patients had a serum IGF-1 below the fifth percentile of the normal group but above the fifth percentile of the ISS group. Thus, a serum IGF-1 below the fifth percentile of the normal group distinguished between normal children and iGHD with 100% sensitivity, between normal and oGHD with 53% sensitivity and between normal and all GHD (idiopathic + organic) with 84% sensitivity; the overall specificity was only 57%. Conversely, a serum IGF-1 below the fifth percentile of the ISS population distinguished between ISS and iGHD with 93% sensitivity, between ISS and oGHD with 33% sensitivity and between ISS and all GHD with 72% sensitivity; the overall specificity was then 95%. CONCLUSIONS: A serum IGF-1 within the normal range virtually excludes idiopathic GHD but does not rule out organic GHD, whereas an IGF-1 below the ISS range is strongly in favour of GHD, after exclusion of poor nutritional status and/or liver disease. An IGF-1 below the normal range but in the idiopathic short stature range gives no definitive conclusion even when it is associated with a low GH peak. Thus, whereas reference values obtained in normal children must be used to interpret serum IGF-1 in short prepubertal children, reference data obtained in idiopathic short stature children should also be taken into account.

Child↗
PubMed2000

Hyperparathyroidism: the limits of surgery in cases of bone or cardiovascular involvement.

In primary hyperparathyroidism (PHPT), asymptomatic bone disease can be detected by bone densitometry. The bone mineral density is about 10% lower than normal control values, especially in the cortical radius. Without parathyroidectomy, bone mineral density is frequently stable, but a few patients, mostly postmenopausal women, have a significant decrease. Histology shows maintenance of trabecular connectivity but with an increase in cortical porosity. After parathyroidectomy, bone mineral density increases, particularly at the lumbar spine and femoral neck, and the benefit persists after 10 years. The fracture risk is controversial but risk of trabecular bone fracture may be higher than that for controls. The impact of PHPT on survival is also controversial, but highest quartile of serum calcium, osteoporosis, old age, and low lean mass are each associated with a death risk. There is also a debate about the criteria for distinguishing between asymptomatic and symptomatic PHPT and about the bone mineral density threshold that should be used as a basis to recommend surgery. The rate of progression of PHPT is slow but in some cases bone loss progresses, justifying bone mineral density follow-up. The frequency of inadequate follow-up and the cost of nonoperative follow-up are in favor of recommending surgery. With broader indications for surgery, it is mandatory to improve the biochemical diagnosis of PHPT.

Bone Density↗
PubMed2000

Hormonal factors influencing weight and growth pattern in craniopharyngioma.

Patients operated on for craniopharyngioma frequently suffer from hyperphagia and are obese, but their statural growth is normal despite growth hormone (GH) deficiency. We have evaluated the hormonal factors influencing changes in weight and growth in 17 children before and 1, 3-6, 12, and/or 24 months after surgical resection of a craniopharyngioma performed at 7.7 +/- (SE) 1 years of age. Of these, 15 patients had a GH deficiency before surgery, and all had complete pituitary deficiency after it. The plasma fasting insulin concentrations before surgery were positively correlated with body mass index (BMI, kg/m(2); p < 0.05), plasma insulin-like growth factors (IGFI, p = 0.03, and IGFII, p = 0.04), and leptin (p = 0.03). They increased significantly 1 month after surgery and continued to increase thereafter, whereas leptin increased significantly only 3-6 months after surgery, paralleling changes in BMI. The plasma fasting insulin concentrations before surgery were also positively correlated with the weight changes (12.3 +/- 2.3 kg, p < 0.01) during the 12 months after surgery, but not with changes in BMI SDS (3.1 +/- 0.5, p = 0.07). Both expressions of weight change were correlated with the concomitant growth rates (4.8 +/- 0.7 cm, p < 0.01). IGFI was above the 10th percentile for children with idiopathic short stature in 10 of 15 patients with craniopharyngioma-induced GH deficiency and IGF-binding protein 3 in 14 of 15 patients. Craniopharyngioma itself modified the control of insulin secretion, and surgery increased the insulin secretion which continued in the same way in a given patient after surgery. The increased insulin secretion in turn increases weight and keeps IGFI nearly normal. This may explain the normal growth rate despite the complete lack of GH.

Body Mass Index↗
PubMed2000

Space flight is associated with rapid decreases of undercarboxylated osteocalcin and increases of markers of bone resorption without changes in their circadian variation: observations in two cosmonauts.

BACKGROUND: Microgravity induces bone loss by mechanism(s) that remain largely unknown. METHODS: We measured biochemical markers related to bone remodeling in two cosmonauts before, during, and after 21- and 180-day space flights, respectively. RESULTS: During both flights, type I procollagen propeptide and bone alkaline phosphatase decreased as early as 8 days after launch. Undercarboxylated osteocalcin percentage increased early and remained high during both flights. Vitamin K supplementation restored carboxylation of osteocalcin during the long-term flight. Urinary and serum C-telopeptide of type I collagen (CTX) increased as early as day 8 of the flights; the increase was greater in serum than in urine. Pyridinoline, free deoxypyridinoline, and N-telopeptide increased less than CTX during the short-term space flight. The circadian rhythm of bone resorption assessed by urine CTX and free deoxypyridinoline was not altered by microgravity. CONCLUSION: Vitamin K metabolism or action and bone remodeling may be altered in cosmonauts.

Adult↗