Publications by authors named "Jan C Roos"

Osteonecrosis and decline of bone density are serious side effects during and after treatment of childhood acute lymphoblastic leukemia. It is unknown whether osteonecrosis and low bone density occur together in the same patients, or whether these two osteogenic side-effects can mutually influence each other's development. Bone density and the incidence of symptomatic osteonecrosis were prospectively assessed in a national cohort of 466 patients with acute lymphoblastic leukemia (4-18 years of age) who were treated according to the dexamethasone-based Dutch Child Oncology Group-ALL9 protocol.

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Purpose: To elucidate incidence and risk factors of bone mineral density and fracture risk in children with Acute Lymphoblastic Leukemia (ALL).

Methods: Prospectively, cumulative fracture incidence, calculated from diagnosis until one year after cessation of treatment, was assessed in 672 patients. This fracture incidence was compared between subgroups of treatment stratification and age subgroups (Log-Rank test).

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Objective: Osteoporosis and fractures are frequently encountered in patients with Crohn's disease. In order to prevent fractures, treatment with bone protecting drugs appears warranted early in the course of bone disease when bone loss is not yet prominent. We therefore aimed to demonstrate a beneficial effect on bone density of the bisphosphonate risedronate in osteopenic Crohn's disease patients.

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Purpose: To assess the intra- and inter-rater reliability of a standardized protocol for measuring proximal tibia and distal femur bone mineral density (BMD) using dual-energy X-ray absorptiometry (DXA).

Methods: Ten able-bodied individuals (7 males) participated in this study. During one measurement session, the knee of each participant was scanned twice by rater 1 using DXA.

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Background And Aims: Decreased bone mineral density (BMD) is common in Crohn's disease (CD) patients. This paper reports on the prevalence of decreased BMD in a referral cohort study of CD-patients next to the change of BMD over time in relation with CD-associated clinical characteristics.

Methods: 205 CD patients of a referral hospital were enrolled between January1998-January 2010 when measurement of BMD by dual X-ray absorptiometry (DXA) was available.

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Purpose: Laminectomy is a standard surgical procedure for elderly patients with symptomatic degenerative lumbar stenosis. The procedure aims at decompression of the affected nerves, but it also causes a reduction of spinal shear strength and shear stiffness. The magnitude of this reduction and the influence of bone mineral density (BMD) and disc degeneration are unknown.

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Unlabelled: Immuno-PET is an appealing concept in the detection of tumors and planning of antibody-based therapy. For this purpose, the long-lived positron emitter (89)Zr (half-life, 78.4 h) recently became available.

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Introduction: Studies on the association of vitamin D and bone mineral density (BMD) in adolescence and young adults have shown contrasting results. None of these studies have examined the course and baseline in vitamin D intake. The purpose of this study was to examine the association between baseline and the course of dietary vitamin D intake on the BMD.

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Context: Increasing evidence suggests that adverse conditions during prenatal life are associated with the development of chronic diseases in adult life. It is still unclear whether in vitro fertilization (IVF) conception could affect the vulnerable developmental processes in humans occurring during early prenatal development with long-term perturbations of developmental pathways.

Objective: Our objective was to examine body composition in 8- to 18-yr-old IVF singletons and spontaneously conceived controls born from subfertile parents.

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Objective: Our objective was to assess final height (FH) and adverse effects of combined GH and GnRH agonist (GnRHa) treatment in short adolescents born small for gestational age or with normal birth size (idiopathic short stature).

Design And Patients: Thirty-two adolescents with Tanner stage 2-3, age and bone age (BA) less than 12 yr for girls or less than 13 yr for boys, height sd score (SDS) less than -2.0 SDS or between -1.

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Background: The aim of this study was to analyze swallowing outcome in advanced oral/oropharyngeal cancer patients treated with microvascular reconstructive surgery and adjuvant radiotherapy.

Methods: Eighty patients were included. Patient, tumor, and treatment factors were assessed.

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Purpose: Immuno-positron emission tomography (PET), the combination of PET with monoclonal antibodies (mAb), is an attractive option to improve tumor detection and to guide mAb-based therapy. The long-lived positron emitter zirconium-89 ((89)Zr) has ideal physical characteristics for immuno-PET with intact mAbs but has never been used in a clinical setting. In the present feasibility study, we aimed to evaluate the diagnostic imaging performance of immuno-PET with (89)Zr-labeled-chimeric mAb (cmAb) U36 in patients with squamous cell carcinoma of the head and neck (HNSCC), who were at high risk of having neck lymph node metastases.

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Unlabelled: Long-term GH treatment in GH-deficient men resulted in a continuous increase in bone turnover as shown by histomorphometry. BMD continuously increased in all regions of interest, but more in the regions with predominantly cortical bone.

Introduction: Adults with growth hormone (GH) deficiency have reduced rates of bone turnover and subnormal BMD.

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Objective: GH-deficient adults have changes in body composition, bone mineral density (BMD) and lipid profile that can be altered by GH substitution. However, long-term data on GH substitution (up to 10 years of follow-up) are limited.

Design: The effects of 10 years of GH replacement therapy on BMD, body composition, bone parameters, serum lipids and glucose metabolism were studied.

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Radiolabeled monoclonal antibodies (MAbs) can add a dimension to diagnostic imaging and staging of metastatic head and neck cancer, as well as in eradication of this disease. The vast majority of malignancies arising in the oral cavity, pharynx and larynx are squamous cell carcinomas. This common cellular origin makes it attractive to search for appropriate tumor-associated antigens, which are preferentially expressed in these neoplasms.

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Undernutrition in early life may permanently change body structure, physiology and metabolism and leads to chronic diseases in later life. To test whether malnutrition during different critical time periods around birth in the rat has long-lasting effects on body composition and skeletal growth, we examined body weight and body composition in pubertal rats and adult rats of 6 months after pre- and postnatal malnutrition. Prenatal malnutrition or intra-uterine growth retardation (IUGR) was induced by ligation of the uterine arteries on day 17 of gestation and postnatal food restriction (FR) by litter enlargement to 20 pups per mother from day 2 after birth until weaning (day 24).

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Between-center variation in bone densitometry may influence the frequency of the diagnosis of osteoporosis. To evaluate this problem, dual-energy X-ray absorptiometry (DXA) machines of the medical centers in the northwest of The Netherlands were evaluated. Four phantoms were used to test the 17 DXA machines of 16 participating centers.

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Unlabelled: Previous studies have shown the potential of murine and chimeric anti-CD44v6 monoclonal antibodies (MAbs) for radioimmunotherapy (RIT) of head and neck squamous cell carcinoma (HNSCC). A limitation of these MAbs, however, appeared to be their immunogenicity. Therefore, humanized monoclonal antibody BIWA 4 (bivatuzumab), with an intermediate affinity for CD44v6, was recently selected.

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Unlabelled: From December 1999 until July 2001, a phase I dose escalation study was performed with (186)Re-labeled bivatuzumab, a humanized monoclonal antibody against CD44v6, on patients with inoperable recurrent or metastatic head and neck cancer. The aim of the trial was to assess the safety and tolerability of intravenously administered (186)Re-bivatuzumab and to determine the maximum tolerated dose (MTD) of (186)Re-bivatuzumab. The data were also used for dosimetric analysis of the treated patients.

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Purpose: In previous studies, we have shown the potential of radioimmunotherapy (RIT) with (186)Re-labeled chimeric monoclonal antibody (MAb) U36 for treatment of head and neck cancer. A limitation of this anti-CD44v6 MAb, however, appeared to be its immunogenicity, resulting in human antichimeric antibodies in 40% of the patients. Aiming for a less immunogenic anti-CD44v6 MAb, the humanized MAb BIWA 4 (bivatuzumab) was introduced.

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Little is known about the influence of long-term daily physical activity (PA) on lumbar bone mass after peak bone mass has been reached, that is, during [young] adulthood. The purpose of this study was to investigate the longitudinal relationship between PA and lumbar bone mineral density (LBMD) in healthy subjects over a 10-year period. The data reported here relate to 225 male and 241 female participants in the Amsterdam Growth and Health Longitudinal Study, who were measured at the mean ages of 27, 32, and/or 36.

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Purpose: In an earlier Phase I radioimmunotherapy (RIT) study with rhenium-186-labeled chimeric monoclonal antibody (cMAb) U36 in patients with refractory head and neck squamous cell carcinoma, the maximum tolerated activity was established at 1.0 GBq/m2, at which bone marrow doses ranged from 0.7 to 1.

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The efficacy and safety of oral pamidronate was examined in a double-blind, placebo-controlled trial in women and men with established osteoporosis. Seventy-eight postmenopausal women and 23 men with at least one prevalent vertebral fracture were randomized separately to 150 mg/day of pamidronate or placebo for 3 years followed by 150 mg/day of pamidronate for an additional 2 years. In addition, all patients received 400 U/day of cholecalciferol and 500 mg/day of elemental calcium.

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Unlabelled: Captopril-stimulated renography is widely used to screen selected groups of hypertensive patients for renal vascular disease. Evaluation of the test is a complex task. Lack of interobserver agreement on the assessment and interpretation of renographic parameters may contribute to differences in sensitivity and specificity between studies.

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