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J C Netelenbos

Publications and source records attributed to J C Netelenbos.

At least 19 recordsLinked to original sources
PubMed2006

[Teriparatide: an anabolic drug for the treatment of patients with osteoporosis].

The management of osteoporosis has been dominated by the use of antiresorptive agents, such as bisphosphonates and raloxifene, which have been shown to effectively reduce the risk of osteoporotic fractures. Teriparatide, a recombinant human parathyroid hormone, has recently become available. It has an altogether different action. Teriparatide is an anabolic agent that primarily stimulates bone formation. This leads to an increase in bone volume and the bone structure and microarchitecture is restored by an increase in trabecular thickness and an increase in the number of connections between trabeculae. Clinically relevant studies on teriparatide in postmenopausal women and in men have shown that it significantly lowers the risk of fracture. Teriparatide should not be combined with bisphosphonates. There are no clear recommendations on the order of treatment with teriparatide and bisphosphonates. The high costs ofteriparatide have slowed the trajectory from registration to reimbursement in the Netherlands. Since 1 February 2005 teriparatide may be prescribed for postmenopausal women with serious osteoporosis i.e. with a minimum of 1 osteoporotic fracture who (a) despite treatment with bisphosphonates or raloxifene after 2 prolapsed vertebrae once again have 1 or more fractures (inadequate response); (b) can tolerate neither bisphosphonates nor raloxifene; (c) are prescribed the drug by their treating medical specialist.

Bone Density Conservation Agents↗
PubMed2006

Oxybutynin: dry days for patients with hyperhidrosis.

We report the case of a 56-year-old postmenopausal woman who was referred to our Endocrinology Outpatient Clinic because of severe hyperhidrosis. She had a four-year history of excessive sweating of her face and upper body. On presentation no sweating could be documented. Physical examination was also unremarkable. It appeared that five days earlier her general practitioner had prescribed oxybutynin for urge incontinence and this accidentally cured her hyperhidrosis. She was diagnosed with idiopathic hyperhidrosis. We advised her to continue the oxybutynin and six months later, she was still symptom-free. Oral anticholinergic drugs are known to be effective for hyperhidrosis, but only anecdotal reports on oxybutynin can be found in the literature. Oxybutynin is not approved for hyperhidrosis, explaining the unfamiliarity with this medicine. This case shows that oxybutynin can be a very effective and simple treatment with only mild side effects. Therefore, oxybutynin merits consideration in patients with idiopathic hyperhidrosis. This report includes a concise review of the causes and treatment options of hyperhidrosis.

Female↗
PubMed2005

Camurati-Engelmann disease (progressive diaphyseal dysplasia) in a Moroccan family.

We report on a 46-year-old mother of Moroccan origin, suffering mainly from painful, swollen legs, and her 26-year-old son who had experienced intense pain in his legs, without fever, for approximately 3 years. They did not have dysmorphic features or abnormal gaits. Radiographic studies of the mother revealed diaphyseal sclerosis of the tibia and spondylosis of the thoracal and lumbar vertebrae. The son had sclerosis of the diaphyses of the metacarpalia of the left hand, the femur and the fibula. The other parts of the skeleton were normal. Several osteosclerotic/hyperostotic disorders, such as melorheostosis (present mostly in sporadic cases and affecting lower extremities) and van Buchem's disease (autosomal recessive and commonly affecting the mandible) were considered as a diagnosis in the proposita. However, similar symptoms in the son of the proposita suggested an autosomal dominant inheritance pattern. This brought us to the diagnosis of progressive diaphyseal dysplasia (PDD) or Camurati-Engelmann disease (CED), an autosomal dominant disorder characterized by limb pain, reduced muscle mass, weakness, a waddling gait, progressive periosteal and endosteal sclerosis of the diaphyses of the long bones and sclerosis of the skull base. Mutations in the transforming growth factor (TGF)-beta1 gene on chromosome 19q13.1 have been reported to cause this disorder. The diagnosis of PDD/CED in this family was confirmed at the molecular level by detection of a C-to-T transition at position 466, leading to an arginine-to-cysteine amino acid change (position 156) in exon 2 of the transforming growth factor-beta1 (TGFB1) gene.

Adult↗
PubMed2005

Risk factors determining active urinary stone formation in patients with urolithiasis.

AIMS: The goal of clinical and metabolic evaluation of patients with urinary stones is to identify patients at high risk for recurrent stone formation and as such, to allow the practitioner to suggest preventive therapies. However, knowledge about risk factors for active stone formation in patients with urolithiasis is limited. This study was initiated to assess the significance of several metabolic and clinical parameters for the determination of the risk of active stone formation. METHODS: Study in 320 consecutive outpatients referred to our clinic for metabolic analysis. Clinical and metabolic parameters were determined by standardized procedures of questionnaires, serum biochemical profiles and urinalysis. RESULTS: In 21.5% of 284 patients with complete data stone formation was active. Hypercalciuria, hypocitraturia and urinary tract infections had odds ratios for active stone formation above 2.5, whereas the odds ratio of a positive family history was 0.38. Hyperuricosuria, hyperoxaluria and a low urinary volume did not influence the risk for active stone formation. CONCLUSION: The risk profile for active stone formation differs from the risk profile for urolithiasis in general. Metabolic evaluation and determination of those risk factors in patients with urolithiasis might improve the estimation of the risk of future stone formation.

Adult↗
PubMed2004

Interindividual differences of medial temporal lobe activation during encoding in an elderly population studied by fMRI.

Functional MRI (fMRI) is used to study medial temporal lobe (MTL) activation during encoding of new information into memory. In most studies, fMRI data of different subjects are averaged in standard coordinate space. However, interindividual differences in activation can be extensive, reflecting functional heterogeneity. Further, anatomical differences in brain structure cause additional variance and loss of registration accuracy. Such differences in structural and functional MTL characteristics may interfere with the efficiency of averaging data across subjects, and may become more significant with aging and dementia. The current study concerns the analysis of individual differences in MTL activation associated with episodic encoding.Twenty-nine healthy elderly men between 60 and 70 years old performed a simple face encoding task during fMRI scanning. Individual data were analyzed in native space, and compared to the group average in standard space (Talairach and Tournoux).MTL volumes between subjects varied between 6.34 and 11.27 cm(3), and had considerable variation when mapped to standard space. Eighteen of the 29 subjects showed MTL activity and activation patterns varied both in location and size (ranging from 0.11 to 1.78 cm(3)), with the strongest activation in the left posterior part of the MTL. In standard space, no region was significantly activated on a group level at a comparable alpha level. We conclude that while the majority of elderly subjects show MTL activation during episodic encoding of faces, there is considerable structural and functional variability between subjects. Group analysis in standard space may not be appropriate for studies of a complex structure such as the MTL, particularly not in aging and dementia.

Aged↗
PubMed2004

Reproducibility of bone mineral density measurement in daily practice.

BACKGROUND: Bone mineral density (BMD) measurements are frequently performed repeatedly for each patient. Subsequent BMD measurements allow reproducibility to be assessed. OBJECTIVE: To examine the reproducibility of BMD by dual energy x ray absorptiometry (DXA) and to investigate the practical value of different measures of reproducibility in a group of postmenopausal women. METHODS: Ninety five women, mean age 59.9 years, underwent two subsequent BMD measurements of spine and hip. Reproducibility was expressed as smallest detectable difference (SDD), coefficient of variation (CV), and intraclass correlation coefficient (ICC). Sources of variation were investigated by multilevel analysis. RESULTS: The median interval between measurements was 0 days (range 0-45). The mean difference (SD) between the measurements (g/cm(2)) was -0.001 (0.02) and -0.0004 (0.02) at L1-4 and the total hip, respectively. At L1-4 and the total hip, SDD (g/cm(2)) was +/-0.05 and +/-0.04 and CV (%) was 1.92 and 1.59, respectively. The ICC at spine and hip was 0.99. CONCLUSIONS: Reproducibility in the postmenopausal women studied was good. In a repeated DXA scan a BMD change exceeding 2 radical 2CV (%), the least significant change (LSC), or the SDD should be regarded as significant. Use of the SDD is preferable to use of the CV and LSC (%) because of its independence from BMD and its expression in absolute units. Expressed as SDD, a BMD change of at least +/-0.05 g/cm(2) at L1-4 and +/-0.04 g/cm(2) at the total hip should be considered significant.

Absorptiometry, Photon↗
PubMed2003

Oestrogen replacement therapy lowers plasma levels of asymmetrical dimethylarginine in healthy postmenopausal women.

Oestrogen replacement therapy (ERT) has been shown to lead to favourable changes in the cardiovascular risk profile of postmenopausal women. Part of this effect is ascribed to increased production or bioavailability of nitric oxide (NO). We have tested the hypothesis that ERT lowers plasma levels of asymmetrical dimethylarginine (ADMA), an endogenous inhibitor of NO synthase (NOS). In a randomized double-blind study design, 40 hysterectomized postmenopausal women received conjugated equine oestrogen (CEE; 0.625 mg/day; n =14), the selective oestrogen receptor modulator raloxifene (150 mg/day; n =13) or placebo ( n =13). At baseline and after 6, 12 and 24 months of treatment, plasma was analysed for levels of arginine, ADMA, and symmetrical dimethylarginine (SDMA), a stereoisomer of ADMA that does not inhibit NOS. An overall treatment effect on ADMA levels was observed in the CEE group ( P =0.004 compared with placebo), but not in the raloxifene group ( P =0.50). The decrease of ADMA levels by CEE treatment was consistent over the 2-year study period, without significant differences between the effects at 6, 12 and 24 months. The average post-baseline change in ADMA in the CEE group compared with placebo was -7.8% (95% confidence interval -12.8% to -2.9%; P =0.003). Arginine or SDMA levels did not change during treatment in any of the groups. Thus ERT with oral conjugated oestrogen, but not with raloxifene, significantly reduced plasma concentrations of the cardiovascular risk factor ADMA in healthy postmenopausal women.

Analysis of Variance↗
PubMed2002

Effect of 1 year of discontinuation of raloxifene or estrogen therapy on bone mineral density after 5 years of treatment in healthy postmenopausal women.

The beneficial effects of hormone replacement therapy (HRT), selective estrogen receptor modulators (SERMs), or bisphosphonates in the prevention and treatment of osteoporosis in postmenopausal women have been well established. However, little is known about the effects of discontinuation of treatment on bone mineral density. We investigated the effect of 1 year of discontinuation of the SERM raloxifene (Ral; 60 mg and 150 mg), conjugated equine estrogen (CEE; 0.625 mg), and placebo after 5 years of treatment in a double-blind, randomized study. Thirty-eight of 59 healthy and hysterectomized postmenopausal women (mean age 55 years) completed the treatment and 1 year follow-up period. Lumbar spine and femoral neck bone mineral density (BMD) were performed with dual-energy X-ray absorptiometry, before, during, and at the end of treatment, as well as after 1 year of discontinuation of therapy. One year of discontinuation significantly reduced the mean lumbar spine BMD in the raloxifene- and estrogen-treated women (p < 0.05), whereas mean femoral neck BMD was reduced significantly only in women treated with 60 mg Ral (p < 0.05). The mean percentage change (+/-SD) in lumbar spine BMD was: CEE, -6.2% (+/-3.7%); Ral 60 mg, -2.4% (+/-2.4%); Ral 150 mg, -2.6% (+/-3.1%); and placebo, -1.6% (+/-4.3%). Our results show that 5 years of treatment with either Ral or CEE did not protect against bone loss after 1 year of withdrawal of therapy, and that the rate of bone loss was not significantly different from that of placebo-treated women.

Bone Density↗
PubMed2002

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.

Adolescent↗
PubMed2001

[Bisphosphonate treatment prevents hip fractures in 70-79 year old women with osteoporotic vertebral fractures].

According to the data of a fracture intervention trial, in women aged 55-80 years with vertebral fractures or osteoporosis diagnosed by bone mineral density measurement, treatment with the bisphosphonate alendronate prevented hip fractures with numbers-needed-to-treat within 5 years of treatment of 46 and 66, respectively. In a large risedronate hip fracture study, this new bisphosphonate only showed a beneficial effect in women aged 70-79 years with moderately severe osteoporosis as judged by femoral neck T-score, when one or more vertebral fractures were present at the start of the treatment. The number-needed-to-treat was 29. However, in women aged over 80 years and who were selected predominantly on the basis of clinical risk factors for hip fracture, no effect was found with this drug on hip fracture rate, suggesting that most were not osteoporotic and/or that the clinical risk factors used did not have the clinical utility in identifying hip fracture risk. Other factors besides osteoporosis may play a more important role in causing hip fracture in this elderly group. Diagnosis of osteoporotic vertebral fractures in women aged 70-79 years is predictive of not only new vertebral fractures but also of hip fractures, and could therefore form an indication for drug treatment.

Age Factors↗
PubMed2001

Raloxifene reduces impedance to flow within the uterine artery in early postmenopausal women: a 2-year randomized, placebo-controlled, comparative study.

OBJECTIVE: We sought to investigate the long-term effect of raloxifene and continuous combined hormone replacement therapy (ccHRT) on impedance to flow within the uterine artery in postmenopausal women. STUDY DESIGN: A prospective, randomized, double-blind, placebo-controlled 2-year study was performed in 95 postmenopausal women. They received either 60 mg of raloxifene daily (raloxifene 60 group), 150 mg of raloxifene daily (raloxifene 150 group), ccHRT, or placebo. At baseline and thereafter every 6 months, color Doppler ultrasonography was used to measure the pulsatility index (PI) of the uterine artery. RESULTS: After 24 months of treatment, compared with placebo, significant decreases were found in the PI in the raloxifene 150 group (P = .021) and in the ccHRT group (P = .007). In the raloxifene 150 group compared with the placebo group, after 6 and 24 months, decreases were observed in median PI of -5% and -15%, respectively, and in the ccHRT group decreases of -2% and -19%, respectively, were found. CONCLUSION: Long-term use of 150 mg of raloxifene daily or ccHRT reduces impedance to flow within the uterine artery. This indicates that high-dose raloxifene may exert cardiovascular protection.

Arteries↗
PubMed2001

Raloxifene affects brain activation patterns in postmenopausal women during visual encoding.

Recent brain imaging studies have shown that estrogens alter brain activation patterns upon working memory tasks in postmenopausal women. Estrogens, however, have many systemic side effects. We investigated the effect of the Selective estrogen receptor modulator (SERM) raloxifene on brain activation patterns during a memory task in postmenopausal women with functional magnetic resonance imaging (fMRI). Twenty postmenopausal and right handed women (mean age 65.7 years; SD 3.0) were included in this double blind, placebo controlled and randomized study. Whole brain fMRI was performed before and after three months of daily treatment with raloxifene 60 mg or placebo. Each scanning session consisted of a visual encoding task, a recognition test and a simple photic simulation test. Data analyses was performed with SPM99b software. Specific regions of interest for the tasks were defined based in previous experiments. Visual encoding activated the ventral route, posterior medial temporal lobe and frontal cortex in both groups. Treatment interactions for raloxifene compared to placebo were a decrease in activation in the left parahippocampal gyrus and left lingual gyrus, an increase in activation in the right superior frontal gyrus. The mean recognition test and the simple photic stimulation test showed no treatment interactions. Our results show that raloxifene affects brain activation patterns upon visual encoding in postmenopausal women.

Aged↗
PubMed2001

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.

Absorptiometry, Photon↗
PubMed2000

[Clinical thinking and decision making in practice. A patient with anal cancer and hypercalcemia].

A 57-year-old male patient, recently known with an anal carcinoma with inguinal lymph node involvement, was admitted because of anorexia, nausea, vomiting and constipation. On physical examination the patient was dehydrated, and a systolic murmur, grade III/VI, punctum maximum apex cordis, was heard. Serum calcium was raised (4.50 mmol/l), as was the serum creatinine (328 mumol/l). Both values had been normal 14 days before admission. Serum parathormone was suppressed. A bone scan did not reveal evident lesions in the skeleton. FDG-PET scan showed uptake of the tracer into the bone marrow. A bone biopsy showed metastasis of a squamous cell carcinoma. Shortly after that the patient died. Hypercalcaemia is associated with cancer. Colorectal/anal carcinomas have a low incidence of hypercalcaemia. The prognosis of patients with cancer associated with hypercalcaemia is poor.

Anus Neoplasms↗
PubMed2000

Effect of estrogen on intestinal strontium absorption in postmenopausal women.

OBJECTIVES: there is considerable uncertainty about the underlying cause of decreased intestinal calcium absorption that occurs in postmenopausal women. In a previous study, estrogen treatment did not result in an increased intestinal calcium absorption using strontium as a marker. A possible explanation could be that the calcium/strontium load given to the women was too high ( approximately 600 mg Ca), which might result in an insensitive test with respect to the possible stimulation of active strontium transport by estrogen. Therefore, the purpose of this study was to reinvestigate the effect of estrogen on active intestinal strontium absorption using a load of 2.5 mmol of strontium only. METHODS: the effect of estrogen on intestinal strontium absorption was measured in eight normal postmenopausal women. The study included two baseline strontium absorption tests, which were performed with an interval of 10 days for calculating the within subject variation (SER). Thereafter the effect of 2 months of estrogen treatment on intestinal strontium absorption was assessed. Fractional absorption (FC(240)) and the area under the concentration time curve (AUC) 4 h after an oral strontium load of 2.5 mmol were calculated. RESULTS: the within subject SER of FC(240) and AUC(0-240) were 2.3+/-0.76 and 1.2+/-0.41, respectively. FC(240) and AUC(0-240) of strontium were unchanged after treatment with estrogen. CONCLUSIONS: in normal postmenopausal women, we did not find a modulating effect of short-term treatment with a (supra) physiological dose of estrogen on intestinal calcium absorption as measured by the strontium absorption test.

Area Under Curve↗
PubMed2000

Ultrasound assessment of the endometrium in healthy, asymptomatic early post-menopausal women: saline infusion sonohysterography versus transvaginal ultrasound.

OBJECTIVE: To exclude pre-existing endometrial pathology in asymptomatic early post-menopausal women before starting hormone replacement therapy by transvaginal ultrasound (TVS) and saline infusion sonohysterography (SIS). METHODS: In a cross-sectional study, 148 healthy women (mean age, 51.1 years; range, 46-59 years) underwent ultrasound evaluation of the endometrium before participation in a clinical trial. TVS was used to measure double-layer endometrial thickness. SIS was performed at the same visit to measure anterior and posterior single-layer endometrial thickness, and to identify endometrial abnormalities when present. Ultrasound results were defined as informative if the endometrium could be adequately visualized. Findings on TVSs were defined as abnormal if a double-layer endometrial measurement > 5.0 mm was obtained. Findings on SIS were defined as abnormal if one or both single layers of the endometrium measured > 2.5 mm, or if focal endometrial thickening or a polyp was present. RESULTS: Of the 148 eligible women, informative TVS results were obtained from 134 women, SIS results from 133 women and both procedures combined from 119 women. TVS scans gave abnormal results in 8.2% of women (11 of 134) and SIS gave abnormal results in 36.8% of women (49 of 133). Of the 14 women with a non-informative TVS, eight had abnormal SIS results. Of the 15 women with a non-informative SIS, three had abnormal TVS results. In the 119 women with both informative TVS and SIS, abnormal TVS scans were found in 6.7% of women (eight of 119) and abnormal SIS in 34.5% of women (41 of 119). All eight women with abnormal TVS had an abnormal SIS, whereas 29.7% (33 of 111) of the women with a normal TVS had an abnormal SIS. CONCLUSIONS: Ultrasound evaluation demonstrated endometrial abnormalities in 34.5% (41 of 119) of asymptomatic post-menopausal women. SIS is more accurate than TVS in the detection of endometrial abnormalities.

Endometrium↗