Markku Parviainen

Impaired Development of Bone Mineral Density During Chemotherapy: A Prospective Analysis of 46 Children Newly Diagnosed with Cancer

Osteopenia and osteoporosis are becoming increasingly recognized in children with cancer, though reasons for these changes are poorly understood. The purpose of the present study was to evaluate longitudinal changes in bone mineral density (BMD) and bone turnover in newly diagnosed children with a malignancy. Lumbar spine (L2–L4) and femoral neck bone mineral density (BMDareal, g/cm2) was measured by dual‐energy X‐ray absorptiometry in 46 children (age 2.9–16.0, median 8.0 years; 15 leukemias, 12 lymphomas, 19 solid tumors) at diagnosis, and after 6 months from the baseline. The apparent volumetric bone mineral density (BMDvol) was calculated to minimize the effect of bone size on BMD. Serum levels of osteocalcin (OC), type I collagen carboxy‐terminal propeptide (PICP), and type I collagen carboxy‐terminal telopeptide (ICTP) were analyzed at diagnosis, and during a 6‐month follow‐up. A significant decrease in lumbar BMDvol (–2.1%, p < 0.05), and in femoral BMDareal (–9.9%, p = 0.0001) and BMDvol (–8.5%, p = 0.0001) was observed after 6 months when compared with baseline measurements. The markers of bone formation (PICP, OC) were significantly decreased, and the marker of bone resorption (ICTP) was significantly increased at diagnosis as compared with normal values. By the end the follow‐up, the levels of PICP and OC were normalized, whereas the level of ICTP continued to increase indicating that there was a negative balance in bone turnover. A deficient accumulation of bone mass might predispose children with a malignancy to impaired development of peak bone mass. A controlled study determining the benefits of an early intervention on bone turnover should be considered in these patients.

An improved method for routine determination of vitamin D and its hydroxylated metabolites in serum from children and adults

A method for routine determination of vitamin D and its major metabolites 25-hydroxyvitamin D (25(OH)D), 24,25-dihydroxyvitamin D (24,25(OH)2D) and 1,25-dihydroxy-vitamin D (1,25(OH)2D) in serum samples from normal children and adults has been developed. Methodological improvements enable a rapid and accurate analysis of 25(OH)D and also the microscale screening of other metabolites present in large concentrations in serum. Vitamin D and its metabolites are extracted from serum samples using hexane/propan-2-ol, which allows a convenient separation of the water soluble and lipid soluble fractions from each other and also from proteins. Preparative silicic acid chromatography was used to separate vitamin D from its metabolites and also from the major portion of co-eluting lipid contaminants. An automated LC solvent delivery and sample introduction system was used to achieve the rapid separation of metabolites. Vitamin D was further purified using adsorption high-performance liquid chromatography and assayed using reverse phase high-performance liquid chromatography connected with UV detection. The 25(OH)D fraction from the preparative chromatography was measured by a competitive protein-binding assay along with 24,25(OH)2D, which was purified by reverse phase high-performance liquid chromatography along with 1,25(OH)2D. A diluted human serum from a pregnant woman (3rd trimester of pregnancy) was used as source of the binding protein for 25(OH)D and 24,25(OH)2D. 1,25(OH)2D was determined by a competitive protein-binding assay using a diluted cytoplasmic 1,25(OH)2D receptor protein isolated from the intestinal mucosa of rachitic chicks. Vitamin D and its metabolite levels were assayed in serum samples from normal children and adults.

Does apolipoprotein E genotype relate to BMD and bone markers in postmenopausal women

OBJECTIVES Bone mineral density (BMD) and development of osteoporosis are partly determined by genetic factors. The associations between one of suggested candidate, apolipoprotein E (apo E) genotype to bone mineral density (BMD) and bone biochemical markers was studied in 464 subjects recruited from a population-based group of early postmenopausal women (n = 13100). Additionally, the influence of apo E genotype on BMD changes during a 5-year follow-up with or without hormone replacement therapy (HRT) was investigated. METHODS Participants were randomized into two treatment groups: HRT group: Sequential combination of 2 mg estradiol valerate and 1 mg cyproterone acetate with or without vitamin D3, 100-300 IU/day + calcium lactate, 500 mg/day (n = 232), and the non-HRT group: Calcium lactate, 500 mg/day alone or in combination with vitamin D3, 100-300 IU/day (n = 232). BMD was measured from the lumbar spine and proximal femur at baseline and after 5 years of treatment (n = 352). In a subgroup (n = 59), the serum concentrations of bone biochemical markers (intact osteocalcin (OC), bone-specific alkaline phosphatase (BAP) and type I collagen carboxy-terminal telopeptide (ICTP)) were measured at baseline and after 1 year of follow-up. RESULTS At baseline, the BMDs were similar between the five apo E genotype groups (2/3, 2/4, 3/3, 3/4, 4/4). No significant differences in lumbar or femoral neck BMDs of women with the apo E4 allele were found compared with those without it. There was a statistically significant difference in 5-year BMD changes between the HRT and non-HRT groups. After 5 years, the BMD of the femoral neck had remained constant and the mean lumbar spine BMD had increased by 1.5% in the HRT group, whereas both BMDs had decreased by 4-5% in the non-HRT group. However, the apo E genotype did not modify the changes in BMD in either group. Additionally, the baseline concentrations of bone metabolic markers and their 1-year changes showed no genotype-related associations. CONCLUSIONS The results of our population-based study indicate that apo E genotype does not modify lumbar or femoral neck BMDs or serum bone biochemical markers or their response to HRT in early postmenopausal Caucasian women.

A comparison of three different methods of concentration of urinary proteins

A number of methods have been described for concentration of urinary proteins prior to electrophoresis, immunoelectrophoresis and other analytical methods, where the original concentration is too low for direct assay. There are, however, several problems connected with each technique. Usually some protein is lost, and the recovery in each method is known to be dependent on at least the molecular size of the protein [l]. In most works, however, this has been ignored: the method for concentrating urine should give the same results regardless of the size of the proteins and of their original concentrations. In addition, the concentration method should not be too cumbersome for routine use. The aim of this investigation was to study the recovery of urinary proteins of various molecular sizes in various concentrations after concentration with three different methods: For this purpose we chose two very widely used methods, namely ultrafiltration and Minicon-B concentrators, and we compared these with a method in which salt removal using small Sephadex columns was followed by lyophilization.

Urinary bone resorption markers in monitoring treatment of symptomatic osteoporosis

We have studied the clinical usefulness of urinary bone resorption markers in postmenopausal women with symptomatic osteoporosis. The study design is a randomised double-blind placebo controlled study, in which the subjects were daily treated for 24 months either with a hormone analogue (2.5 mg Livial, generic name Tibolone, Organon, Amsterdam, Holland) plus 800 mg calcium (n = 14, age 63+/-5 years, range 52-68 years), or with placebo plus 800 mg calcium (n = 19, age 66+/-7 years, range 50-75 years). The laboratory methods for urinary bone resorption markers were enzyme immunoassays (EIA) for urinary pyridoline (PYD) and deoxypyridoline crosslinks (DPD), and for cross-linked N-telopeptides of Type I Collagen (NTx), and an HPLC assay for urinary hydroxyproline (HOP). All the urine assay results were calculated per mmol creatinine. All the resorption markers decreased during the two-year study period in both groups. The Z scores (discriminating power, i.e. ability of the different tests to distinguish the hormone treated subjects from the placebo treated subjects) for HOP and PYD were rather low: 0.06-1.52 for HOP and 0.68-1.47 for PYD. The differences between the two treatment groups were statistically significant for DPD at 12 and 24 months of treatment (P = 0.0471 and P = 0.0466, respectively), the Z scores ranging 0.45-1.90. NTx showed the most prominent decrease from the beginning of the study especially in the hormone treatment group: the differences between the two treatment groups were statistically highly significant for NTx already at 6 months of treatment (P = 0.0015), and the Z scores remained high ranging 2.11-3.82 throughout the two-year study period. Dual X-ray absorptiometry (DXA) of the lumbar spine and femoral neck did not show statistically significant differences between the two treatment groups throughout the two-year study period. After 2 years there was, however, a significant increase in bone density both in the spine (+ 6.6%, P = 0.0002) and in the femoral neck (+ 3.4%, P = 0.0389) in the women with hormone treatment. In the control group a significant increase (+ 5.1%, P = 0.0012) in the spine, whereas a non-significant decrease (-1.5%, n.s.) in the femoral neck was observed. We suggest that measurement of urinary cross-linked peptides derived from Type I collagen (NTx and DPD) might be a useful biochemical method of observing the positive clinical effect (i.e. reduction in bone resorption) following hormone replacement therapy in postmenopausal fracture patients.

Vitamin D and mineral metabolism in intrahepatic cholestasis of pregnancy

Serum concentrations of 25(OH)D, 24,25(OH)2D, 1,25(OH)2D, total protein, calcium, phosphorus, magnesium and alkaline phosphatase were measured in patients with intrahepatic cholestasis of pregnancy and in control subjects at the third trimester of pregnancy and at delivery. 25(OH)D levels of 40.5 +/- 21.5 nmol/l in the patient group were initially significantly (P less than 0.01) higher than the value of 26.3 +/- 9.5 nmol/l in the control group and decreased significantly (P less than 0.01) to 26.0 +/- 16.3 nmol/l at delivery. The levels of active 1,25(OH)2D and inactive 24,25(OH)2D did not alter in either group. Also the concentrations of calcium, phosphorus and magnesium remained unchanged in both groups. No significant differences in fetal vitamin D metabolites were observed between patients and controls, and the other analysed fetal parameters were similar in both groups. Cholestyramine and/or phenobarbital treatment had no influence on vitamin D metabolites. Since levels of 1,25(OH)2D and mineral parameters remained normal and a change in 25(OH)D concentrations was only transient, the clinical role of 25(OH)D variations cannot be substantial.

Can the fetus regulate its calcium uptake

Summary. To investigate the role of the fetus in vitamin D metabolism concentrations of vitamin D metabolites, 25(OH)D, 24,25(OH)2D and 1,25(OH)2D, were measured in human umbilical artery and vein. There were no differences between artery and vein in 25(OH)D and 24,25(OH)2D levels. 1,25(OH)2D concentrations were statistically significantly higher in the artery than in the vein. It has been shown in animal experiments that 1,25(OH)2D is an important factor in the maintenance of the placental calcium gradient. We suggest that the fetus actively produces 1,25(OH)2D and hence has the capacity to control its calcium influx.