Side-by-side comparison of the two widely studied GRPR radiotracers, radiolabeled NeoB and RM2, in a preclinical setting.

INTRODUCTION: NeoB and RM2 are the most investigated gastrin-releasing peptide receptor (GRPR)-targeting radiotracers in preclinical and clinical studies. Therefore, an extensive side-by-side comparison of the two radiotracers is valuable to demonstrate whether one has advantages over the other. Accordingly, this study aims to compare the in vitro and in vivo characteristics of radiolabeled NeoB and RM2 to guide future clinical studies. METHOD: The stability of the radiolabeled GRPR analogs was determined in phosphate buffered saline (PBS), and commercially available mouse and human serum. Target affinity was determined by incubating human prostate cancer PC-3 cells with [177Lu]Lu-NeoB or [177Lu]Lu-RM2, + / - increasing concentrations of unlabeled NeoB, RM2, or Tyr4-bombesin (BBN). To determine uptake and specificity cells were incubated with [177Lu]Lu-NeoB or [177Lu]Lu-RM2 + / - Tyr4-BBN. Moreover, in vivo studies were performed to determine biodistribution and pharmacokinetics. Finally, radiotracer binding to various GRPR-expressing human cancer tissues was investigated. RESULTS: Both radiotracers demonstrated high stability in PBS and human serum, but stability in mouse serum decreased substantially over time. Moreover, both radiotracers demonstrated high GRPR affinity and specificity, but a higher uptake of [177Lu]Lu-NeoB was observed in in vitro studies. In vivo, no difference in tumor uptake was seen. The most prominent difference in uptake in physiological organs was observed in the GRPR-expressing pancreas; [177Lu]Lu-RM2 had less pancreatic uptake and a shorter pancreatic half-life than [177Lu]Lu-NeoB. Furthermore, [177Lu]Lu-RM2 presented with a lower tumor-to-kidney ratio, while the tumor-to-blood ratio was lower for [177Lu]Lu-NeoB. The autoradiography studies revealed higher binding of radiolabeled NeoB to all human tumor tissues. CONCLUSION: Based on these findings, we conclude that the in vivo tumor-targeting capability of radiolabeled NeoB and RM2 is similar. Additional studies are needed to determine whether the differences observed in physiological organ uptakes, i.e., the pancreas, kidneys, and blood, result in relevant differences in organ absorbed doses when the radiotracers are applied for therapeutic purposes.

Imaging heterogeneity of peptide delivery and binding in solid tumors using SPECT imaging and MRI.

BACKGROUND: As model system, a solid-tumor patient-derived xenograft (PDX) model characterized by high peptide receptor expression and histological tissue homogeneity was used to study radiopeptide targeting. In this solid-tumor model, high tumor uptake of targeting peptides was expected. However, in vivo SPECT images showed substantial heterogeneous radioactivity accumulation despite homogenous receptor distribution in the tumor xenografts as assessed by in vitro autoradiography. We hypothesized that delivery of peptide to the tumor cells is dictated by adequate local tumor perfusion. To study this relationship, sequential SPECT/CT and MRI were performed to assess the role of vascular functionality in radiopeptide accumulation. METHODS: High-resolution SPECT and dynamic contrast-enhanced (DCE)-MRI were acquired in six mice bearing PC295 PDX tumors expressing the gastrin-releasing peptide (GRP) receptor. Two hours prior to SPECT imaging, animals received 25 MBq (111)In(DOTA-(ßAla)2-JMV594) (25 pmol). Images were acquired using multipinhole SPECT/CT. Directly after SPECT imaging, MR images were acquired on a 7.0-T dedicated animal scanner. DCE-MR images were quantified using semi-quantitative and quantitative models. The DCE-MR and SPECT images were spatially aligned to compute the correlations between radioactivity and DCE-MRI-derived parameters over the tumor. RESULTS: Whereas histology, in vitro autoradiography, and multiple-weighted MRI scans all showed homogenous tissue characteristics, both SPECT and DCE-MRI showed heterogeneous distribution patterns throughout the tumor. The average Spearman's correlation coefficient between SPECT and DCE-MRI ranged from 0.57 to 0.63 for the "exchange-related" DCE-MRI perfusion parameters. CONCLUSIONS: A positive correlation was shown between exchange-related DCE-MRI perfusion parameters and the amount of radioactivity accumulated as measured by SPECT, demonstrating that vascular function was an important aspect of radiopeptide distribution in solid tumors. The combined use of SPECT and MRI added crucial information on the perfusion efficiency versus radiopeptide uptake in solid tumors and showed that functional tumor characteristics varied locally even when the tissue appeared homogenous on current standard assessment techniques.

Improving radiopeptide pharmacokinetics by adjusting experimental conditions for bombesin receptor-targeted imaging of prostate cancer.

AIM: Prostate cancer (PC) is a major health problem. The Gastrin-Releasing Peptide Receptor (GRPR) offers a promising target for staging and monitoring of PC since it is overexpressed in PC and not in normal prostatic tissue. To improve receptor-mediated imaging we investigated the impact of various experimental conditions on pharmacokinetics using the Indium-111 labelled bombesin (BN) analogue AMBA. Besides frequently used androgen-resistant PC-3 also the clinically more relevant androgen sensitive VCaP celline was used as human PC xenograft in nude mice. METHODS: Non-purified [111In]AMBA was compared with HPLC-purified [111In]AMBA. Effect of specific activity was studied administering 0.1MBq [111In]AMBA supplemented with different amounts of AMBA (1-3000pmol). GRPR was saturated with Tyr4-BN 1 and 4h prior to injection of [111In]AMBA. RESULTS: GRPR-positive tissue showed a significant 2 to 3-fold increase in absolute uptake after HPLC-purification while keeping a stable tumor-to-pancreas ratio. Lowering specific activity resulted in decline in uptake to 43% in tumor, 49% in kidney and 92% in pancreas between 10 and 3000 pmol. Tumor-to-pancreas ratio improved six-fold from 0.1±0 after 10 pmol up to 0.6±0.2 after 3000 pmol (P<0.01). When saturating GRPR 4h prior to [111In]AMBA injection tumor-to-pancreas ratio improved from 0.10±0.3 to 0.22±0.2 (P<0.01) and tumor-to-kidney ratio increased from 0.92±0.16 to 3.45±0.5 (P<0.01). CONCLUSION: Besides specific peptide characteristics also the experimental conditions, such as HPLC-purification, variations in specific activity and saturation of the GRPR prior to [111In]AMBA administration essentially affect radiopeptide pharmacokinetics. Experimental conditions therefore need to be carefully selected in order to compose ideal standardised protocols for optimal targeting.

A transductionally retargeted adenoviral vector for virotherapy of Her2/neu-expressing prostate cancer.

The efficacy of adenovirus (Ad)-based gene therapy of solid tumors, such as prostate cancer, is limited. One of the many problems is that the virus infects many different cell types in the body, resulting in high toxicity, whereas the target cancer cells are often less prone to wild-type Ad infection. Our aim was to develop genetically de- and retargeted Ad vectors to reduce off-target effects and increase target infection for prostate cancer. We have previously reported an Ad5 vector specific for the cancer-associated receptor Her2/neu, created by inserting Her2/neu-reactive Affibody(®) molecules (ZH) into the HI loop of a coxsackievirus and adenovirus receptor binding-ablated fiber (Ad[ZH/1]). In addition to virus retargeting to Her2/neu, this virus was further modified from wild-type Ad by changing the RGD motif in the penton base to EGD and by substitution of the KKTK motif in the third shaft repeat to RKSK, resulting in the vector Ad[ZH/3]. The ZH-containing vectors could be produced to high titers and were specific for their target, resulting in efficient infection and killing of Her2/neu-positive androgen-dependent PC346C prostate cancer cells in vitro. Here we show that the oncolytic Ad[ZH/3] vector significantly prolonged survival time and reduced serum prostate-specific antigen levels in an orthotopic prostate tumor model in nude mice to the same extent as wild-type Ad5. Our results show that Her2/neu targeting using Ad-based vectors for prostate cancer is feasible and may serve as a basis for the development of gene therapy of human prostate cancer as well as other Her2/neu-expressing cancers.

Disconnecting the yin and yang relation of epidermal growth factor receptor (EGFR)-mediated delivery: a fully synthetic, EGFR-targeted gene transfer system avoiding receptor activation.

The epidermal growth factor receptor (EGFR) is upregulated within a high percentage of solid tumors and hence is an attractive target for tumor-targeted therapies including gene therapy. The natural EGFR ligand epidermal growth factor (EGF) has been used for this purpose, despite the risk of mitogenic effects due to EGFR activation. We have developed a fully synthetic, EGFR-targeted gene delivery system based on PEGylated linear polyethylenimine (LPEI), allowing evaluation of different EGFR-binding peptides in terms of transfection efficiency and EGFR activation. Peptide sequences directly derived from the human EGF molecule enhanced transfection efficiency with concomitant EGFR activation. Only the EGFR-binding peptide GE11, which has been identified by phage display technique, showed specific enhancement of transfection on EGFR-overexpressing tumor cells including glioblastoma and hepatoma, but without EGFR activation. EGFR targeting led to high levels of cell association of fluorescently labeled polyplexes after only 30 min of incubation. EGF pretreatment of cells induced enhanced cellular internalization of all polyplex types tested, pointing at generally enhanced macropinocytosis. EGF polyplexes diminished cell surface expression of EGFR for up to 4 hr, whereas GE11 polyplexes did not. In a clinically relevant orthotopic prostate cancer model, intratumorally injected GE11 polyplexes were superior in inducing transgene expression when compared with untargeted polyplexes.

A universal index of uterine discharge symptoms from calving to 6 weeks postpartum.

In this paper, a new uterine discharge index (D-index) was created and tested. It was based on a principal component analysis (PCA) of clinical findings of classical uterine discharge symptoms and rectal temperature during the postpartum period of dairy cattle. The PCA analysis revealed how uterine discharge features relate to each other and how they cluster together possibly representing different degrees of uterine inflammation. The D-index was the result of the multivariate PCA-analysis, and the D-index gives a continuous value between 0 and 10. It was demonstrated that the same scale, i.e. the D-index, can be used without any adjustment from 1 to 6 weeks post-calving. It is valid for any type of uterine discharge without defining the type of infection or differentiating between infection and contamination. The D-index was tested using the uterine involution data. Uterine involution was significantly delayed in the high-D-index group of cows. Similarly, in the test with all cows, involution was progressively delayed and the rate of involution of the pregnant horn was slowed down with the increase of the D-index values. It is concluded that the D-index can be a new practical, universal, tool for improved management of dairy cows in the postpartum period under commercial conditions.

Limits to prediction of energy balance from milk composition measures at individual cow level.

Frequently updated energy balance (EB) estimates for individual cows are especially useful for dairy herd management, and individual-level estimates form the basis for group-level EB estimates. The accuracy of EB estimates determines the value of this information for management decision support. This study aimed to assess EB accuracy through ANOVA components and by comparing EB estimates based either on milk composition (EBalMilk) or on body condition score (BCS) and body weight (BW) (EBalBody). Energy balance based on milk composition was evaluated using data in which milk composition was measured at each milking. Three breeds (Danish Red, Holstein-Friesian, and Jersey) of cows (299 cows, 623 lactations) in parities 1 to 4 were used. Milk data were smoothed using a rolling local regression. Energy balance based on milk composition was calculated using a partial least squares (PLS) model based on milk fat, protein, and lactose contents and yields, and the daily change in these variables at each day. Energy balance based on BCS and BW was calculated from changes in body condition and BW scored weekly or fortnightly. Equations for calculation of EBalMilk and EBalBody used no common variables and were, therefore, assumed mathematically independent. Traits were analyzed within 3 stages of lactation expected to have high mobilization of body tissue (1, early), almost balanced (2), and deposition of body energy (3, mid to late lactation). In general, EBalMilk and EBalBody followed similar expected changes through lactation. Estimates of covariance were obtained using single-trait mixed models with random regression terms describing the change with time and used for calculation of repeatability as intraclass correlations. Within stage, EBalMilk was less repeatable than EBalBody (0.53, 0.41, 0.43 vs. 0.93, 0.91, 0.86, respectively, for stages 1, 2, and 3), mainly because of a larger residual variance for EBalMilk. Correlations between individual-level estimates of EBalMilk and EBalBody were close to zero. However, correlations between EB estimates in different lactation stages tended to be stronger for EBalMilk than for EBalBody, although correlations for both EB traits were small. It is concluded that EB estimates based on milk composition are less accurate than those based on body traits, but EBalMilk can compensate partly for this inaccuracy by being updated more frequently.

Improved detection of reproductive status in dairy cows using milk progesterone measurements.

This study tested a model for predicting reproductive status from in-line milk progesterone ;measurements. The model is that of Friggens and Chagunda [Theriogenology 64 (2005) 155]. Milk progesterone measurements (n = 55 036) representing 578 lactations from 380 cows were used to test the model. Two types of known oestrus were identified: (1) confirmed oestrus (at which insemination resulted in a confirmed pregnancy, n = 121) and (2) ratified oestrus (where the shape of the progesterone profile matched that of the average progesterone profile of a confirmed oestrus, n = 679). The model detected 99.2% of the confirmed oestruses. This included a number of cases (n = 16) where the smoothed progesterone did not decrease below 4 ng/ml. These cows had significantly greater concentrations of progesterone, both minimum and average, suggesting that between cow variation exists in the absolute level of the progesterone profile. Using ratified oestruses, model sensitivity was 93.3% and specificity was 93.7% for detection of oestrus. Examination of false positives showed that they were largely associated with low concentrations of progesterone, fluctuating around the 4 ng/ml threshold. The distribution of time from insemination until the model detected pregnancy failure had a median of 22 days post-insemination. In this test, the model was run using limited inputs, the potential benefits of including additional non-progesterone information were not evaluated. Despite this, the model performed at least as well as other oestrus detection systems.

Priming the cow for mobilization in the periparturient period: effects of supplementing the dry cow with saturated fat or linseed.

High-producing dairy cows experience negative energy balance in early lactation. Dry-cow feeding management will affect the performance and metabolic status of dairy cows in the following early lactation. The present study evaluates dry-cow feeding strategies for priming lipid metabolism in the dairy cow to overcome the metabolic challenges in the following early lactation. Five weeks before expected calving, 27 cows were assigned to 1 of 3 isonitrogenous and isoenergetic dietary treatments: a low-fat control diet (dry-control); a high saturated fat diet (dry-HSF); and a high linseed diet (dry-HUF). The cows were fed the same TMR lactation diet after calving. The treatments were evaluated by performance and metabolic parameters in blood and liver. The cows fed dry-HSF and dry-HUF had significantly greater plasma nonesterified fatty acid concentrations compared with dry-control, and the dry-HUF cows had the greatest C18:3 concentrations in plasma in the prepartum period. Further, the cows fed dry-HSF and dry-HUF diets had a tendency for the greatest capacity for incomplete beta-oxidation of fatty acids in the liver in wk 3 prepartum. The plasma cholesterol concentration was greatest for cows fed dry-HSF in the prepartum period compared with those fed dry-control and dry-HUF. The cows fed dry-HSF had the lowest plasma nonesterified fatty acid and liver fat concentrations in early lactation compared with the cows fed dry-control and dry-HUF. Data in the literature and the present experiment indicate that supplementing dry cows with a saturated fatty acid source is a positive strategy for priming dairy cows for body fat mobilization in the following early lactation.

Estimating degree of mastitis from time-series measurements in milk: a test of a model based on lactate dehydrogenase measurements.

The aim of this study was to test a model for mastitis detection using a logic that allows examination of time-related changes and a progressive scale of mastitis state (i.e., not using specificity/sensitivity). The model produces a mastitis risk (MR) for individual cows on a scale from 0 (completely healthy) to 1 (full-blown mastitis). The main model input was lactate dehydrogenase (LDH; mumol/min per L) x milk yield. Test data containing 253 mastitis cases were used. Proportional samples were collected from each cow at each milking and analyzed for LDH and somatic cell count (SCC). The basis for the health definitions was veterinary treatment records. A refinement of the basic health definitions was made using systematic positive deviations in log(SCC) to indicate untreated infections. Two subsets of cows were identified: mastitic cows and cows completely free of mastitis (healthy controls). The time-profiles of these 2 groups in a 60-d window relative to day of veterinary treatment were examined. Model reliability throughout all stages of lactation and degrees of infection was examined using SCC as a continuous measure of degree of mastitis. The time-profile for the health controls was flat throughout the 60-d window with a median MR of 0.02. In contrast, the profile of the mastitic cows increased above the control cows' baseline from about -6 d, rising to a MR value of 0.20 at d 0, and declining to the control level after treatment. There were significant differences between mastitic and healthy cows from -4 to +2 d relative to veterinary treatment. When cases were time-aligned to peak of infection, rather than veterinary treatment, there was a much sharper peak to the time-profile of mastitic cows. The median MR at peak was 0.62 and the mean was 0.80. Using these data, the MR value of 0.62 had a <1% likelihood of actually coming from a healthy control. Testing against SCC, on the whole data set, showed that only 2.1% of all MR values had an error >0.7. These estimates of model reliability are comparable with the greatest values reported in the literature and, additionally, the model was able to detect significant differences between mastitic and healthy cows 4 d before treatment. It was also found that specificity/sensitivity calculations are inappropriate for evaluating time-related changes and a progressive scale of predicted mastitis state.

On the use of milk composition measures to predict the energy balance of dairy cows.

Milk composition varies with energy status and was proposed for measuring energy balance on-farm, but the accuracy of prediction using monthly samples is not high. With automated sampling and inline milk analysis, a much higher measurement frequency is possible, and thus improved accuracy of energy balance determination may be expected. Energy balance was evaluated using data in which milk composition was measured at each milking. Three breeds (Danish Holstein, Danish Red, and Jerseys) of cows (623 lactations from 299 cows) in parities 1, 2, and 3+ were used. Data were smoothed using a rolling local regression. Energy balance (EBal) was calculated from changes in body reserves (body weight and body condition score). The relationship between EBal and milk measures was quantified by partial least squares regression (PLS) using group means data. For each day in lactation, the within-breed and parity mean EBal and mean milk measures were used. Further PLS was done using the individual cow data. The initial PLS models included 25 combinations of milk measures allowing a range of nonlinear effects. These combinations were as follows: days in milk (DIM); DIM raised to the powers 2, 3, and 4; milk yield; fat content; protein content; lactose content; fat yield; protein yield; lactose yield; fat:protein ratio; fat:lactose ratio; protein:lactose ratio; and milk yield:lactose ratio, together with 10 "diff()" variables. These variables are the current minus the previous value of the milk measure in question. Using group means data, a very high proportion (96%) of the variability in EBal was explained by the PLS model. A reduced model with only 6 variables explained 94% of the variation in EBal. This model had a prediction error of 3.82 MJ/d; the 25-variable model had a prediction error of 3.11 MJ/d. When using individual rather than group means data, the PLS prediction error was 17.3 MJ/d. In conclusion, the mean Ebal of different parities of Holstein, Danish Red, and Jersey cows can be predicted throughout lactation using 1 common equation based on DIM, milk yield, milk fat, and milk protein measures.

Bone metabolism markers and bone mass in healthy pubertal boys and girls.

OBJECTIVE: During puberty, bone growth and mineralization as well as bone turnover increase dramatically. The relation between height velocity and bone turnover is already known, but there are few studies in which both bone metabolism markers and bone mass throughout puberty have been measured. DESIGN: Semi-longitudinal study. In 155 healthy boys (12.0 +/- 1.5 years; range 8.8-15.7 years) and 151 healthy girls (11.2 +/- 1.6 years; range 8.2-14.0 years) markers of bone formation and bone resorption were measured as well as sex steroids, IGF-1 and IGF-BP3, together with bone mineral content (BMC) and bone mineral density (BMD) of the lumbar spine, femur and total body during puberty. All bone measurements were repeated after 1 year. RESULTS: BMC and BMD increased throughout puberty in both sexes. Bone turnover markers increased significantly until maximum values were reached at stage G4 in boys and stage B3 in girls. Height velocity (HV) had a similar changing pattern. Sex steroids and IGF-1 increased and reached adult values at pubertal stage 4. The correlations between bone metabolism markers and BMC were highly significant in boys, while correlations between bone metabolism markers and the increase in BMC over 1 year were significant in both sexes, as was observed for the correlations with HV. CONCLUSIONS: Our data suggest that bone metabolism markers are good predictors of bone mass in boys and of bone mass increase in both sexes. In early puberty, sex steroids stimulate the pubertal growth spurt in conjunction with GH and IGF-1. The fast increase in height gives rise to an increase in bone turnover and bone mineral apposition. It is known that at the end of puberty high levels of oestradiol inhibit chondrocyte proliferation. This leads to a decline in height velocity and bone turnover. Bone mass still increases under the influence of sex steroids and IGF-1. The data in our study confirm previous reports that markers of bone turnover relate positively to height velocity.

Concurrent validity of a weight-bearing activity questionnaire in prepubertal and pubertal girls and boys.

OBJECTIVE: The purpose of this study was to evaluate the current validity of an interviewer-administered physical activity questionnaire against measurement of physical activity from vertical body accelerometer movements in prepubertal and pubertal children. METHODS: The Weight Bearing Activity Questionnaire for Kids (WBAQK) is an interviewer-administered questionnaire with a recall over 7 days and developed to assess weight-bearing activity in pre-pubertal and pubertal children. The Caltrac(TM) accelerometer was worn for 4-5 days (including 1 weekend day). Thirty-seven schoolgirls and 35 schoolboys participated, with a mean age of 11.2 0.3 years and 12.1 0.2 years, respectively. RESULTS: Weight-Bearing Score (WBS) and Metabolic Score (MS) derived from the WBAQK were significantly and positively related to the score of the Caltrac(TM). Weight-Bearing Score showed higher correlations in both boys (0.59) and girls (0.53) and slightly better compared to MS (0.54 and 0.35). The classification of boys and girls into high and low activity groups resulted also in a better agreement of WBS (71-72%) than of MS (60-67%) with Caltrac(TM). CONCLUSIONS: We conclude that the amount of weight-bearing activity can be estimated with the interviewer-administered WBAQK in boys and girls between 8 and 14 years of age.

Validation of transrectal ultrasonographic volumetry for orthotopic prostate tumours in mice.

Orthotopic human prostate tumour models in athymic nude mice are regarded as being most suitable for fundamental and pre-clinical research on prostate cancer. The anatomic localization of the tumour in the pelvis, however, provides little possibility for monitoring tumour growth or regression. To assess time-related changes in orthotopic tumour volume, we applied transrectal ultrasonography (TRUS) to the murine prostate. This technique has the advantages of allowing accurate monitoring of tumours during therapeutic manipulations and a reduction of animal use due to a reduction of sacrificing endpoints. To validate the TRUS method, the mouse prostate reconstitution model, RM-9, and the prostate-specific antigen (PSA) producing human prostate cancer xenograft PC-346 were used. Volumetric calliper measurements were performed with a 30 MHz ultrasound probe designed for intra-arterial use in humans. Tumour weight, determined at various time-points, was found to be closely related to actual tumour weight (R = 0.99) and, in the PC-346 model, to the level of PSA in the plasma. Furthermore, the interobserver variation for TRUS was low for tumours above 50 mg. Thus, TRUS for murine prostate tumours proves to be an accurate, reproducible and sensitive method.

Pubertal maturation characteristics and the rate of bone mass development longitudinally toward menarche.

To assess risks for osteoporosis and to compare bone mass in different groups of healthy children or children with diseases, it is important to have knowledge of their sexual maturation status during puberty. The aim of our study was to evaluate bone mass formation longitudinally in relation to pubertal maturation characteristics in healthy white girls. We investigated the bone mineral content (BMC) and the bone mineral density (BMD) at different skeletal sites in 151 girls with increasing pubertal stages in relation with their chronological age and with an early or late onset of puberty or menarche and with a slow or fast maturation. Bone mass was measured at the onset of puberty, during puberty, and at menarche. We conclude the following: (1) from midpuberty to menarche, the increase in bone mass formation is highest at all skeletal sites in white girls; (2) early mature girls at the onset of puberty have slightly but definitely lower bone masses at all skeletal sites and at all pubertal stages than late mature girls, whereas the average bone mass formation from the onset of puberty to menarche is similar in both groups; (3) girls with a slow rate of pubertal maturation have lower bone mass values 2 years after the onset of puberty, but at menarche bone mass is similar compared with fast maturers; and (4) it cannot be confirmed that there is an effect of menarcheal age on bone mass values at menarche.

Bone mineral density and markers of bone turnover in young adult survivors of childhood lymphoblastic leukaemia.

OBJECTIVE: In order to determine if a serious disease like childhood acute lymphoblastic leukaemia (ALL) and the treatment necessary to cure the patients has long term effects on bone mass, we assessed bone mineral density (BMD) and several parameters involved in bone formation in a group of young adult survivors of ALL. DESIGN AND PATIENTS: Fourteen male and ten female survivors, treated for ALL in childhood, were cross-sectionally studied, at a mean age of 25.1 years (range 20.1-34.9). All patients, except for two, had received cranial irradiation as part of their treatment (mean radiation dose 2460 cGy). MEASUREMENTS: Height and weight were measured. Bone mineral density (BMD) was assessed using dual energy X-ray absorptiometry in the lumbar spine, femoral neck, femoral trochanter and at 1/3 distal and ultradistal in the radius. Early morning serum levels of LH, FSH, oestradiol or testosterone, IGF-1 and IGF-BP3 were determined as well as several specific markers of bone turnover. RESULTS: Mean height, expressed as standard deviation score (SDS) was -1.12, significantly reduced. BMD in the lumbar spine, femoral neck and at 1/3 distal and ultradistal in the radius, was significantly lower compared to the reference population (P < 0.05). No correlation was found between the BMD values and the cumulative dose of administered cytotoxic drugs, the age at diagnosis of ALL or the duration of follow-up. Mean IGF-1 and IGF-BP3 SDS-scores were -1.24 and -0.78 respectively, significantly reduced. GH stimulation tests performed in a subgroup of 9 patients showed an insufficient peak GH response in at least one test in all tested patients. The values of LH, FSH oestradiol or testosterone were within the normal adult range. Serum markers of bone formation and bone resorption were in the normal range, indicating that bone turnover was normal at the time of the study. CONCLUSIONS: Bone development in patients cured of acute lymphoblastic leukaemia is disturbed, resulting in a significantly reduced bone mineral density. Impaired growth hormone activity, as a long term effect of cranial irradiation, may be one of the underlying causes as well as the illness itself and the administered cytotoxic drugs. Since a reduced bone mineral density predispose patients to osteoporosis, intervention in order to improve bone mass should be considered.

Changes in body composition during 12 months after discontinuation of growth hormone therapy in young adults with growth hormone deficiency from childhood.

Little is known about the velocity of changes in body composition after discontinuation of GH therapy at final height. The aim of this study was to describe the changes of fat distribution in male and female GH deficient young adults during the first year after discontinuation of GH therapy. Ten Dutch GH deficient young adults who had reached final height were retested and confirmed to be still GH deficient. These preliminary results demonstrate that the greatest gain in subcutaneous fat, measured by skinfold thickness, was observed in the first 3 months after GH withdrawal. Intra-abdominal fat was measured by CT scan at 0 and 12 months study time. The mean gain in intra-abdominal fat after 12 months was dramatically high (48%). We conclude that the subcutaneous and intra-abdominal fat mass increased dramatically in young GH deficient Dutch adults with GH deficiency, after discontinuation of therapy, especially in the first three months. This indicates that GH therapy should be restarted as soon as possible, after reconfirming the diagnosis of GH deficiency in adults. This will reduce the risk for these patients of diseases associated with overweight, such as cardiovascular diseases.

Clinical utility of markers of bone turnover in children and adolescents.

We review the past years' literature on biochemical markers of bone turnover. A general introduction to markers of bone formation and bone resorption is followed by reference values of bone turnover in neonates, infants, and prepubertal and pubertal children. We describe intervention with calcium and physical activity in healthy children and bone turnover in patients. The predictive value of a single measurement of bone markers in individuals is poor, due to the large biologic intraperson variation for bone markers in general. Serious osteoporosis can be diagnosed by the combined results of measurement of several bone formation and resorption markers.