Integrin-mediated action of insulin-like growth factor binding protein-2 in tumor cells

The neoplastic production of the insulin-like growth factor binding protein (IGFBP)-2 often correlates with tumor malignancy and aggressiveness. Since IGFBP-2 contains an RGD motif in its C-terminus, it was hypothesized that this protein may act independently of IGF on tumor cells through integrins. To investigate this, integrin binding, intracellular signaling and the impact of IGFBP-2 on cell adhesion and proliferation were examined in two tumor cell lines. In tracer displacement studies, up to 30% of the added (125)I-hIGFBP-2 specifically bound to the cells. Bound (125)I-hIGFBP-2 was reversibly displaced by IGFBP-2, IGFBP-1 and RGD-(Gly-Arg-Asp)-containing peptides, but not by IGFBP-3, -4, -5, -6 and RGE-(Gly-Arg-Glu)-containing peptides. Blocking with antibodies directed against different integrins and with fibronectin demonstrated that IGFBP-2 cell surface binding is specific for alpha5beta1-integrin. Incubation of IGFBP-2 with equimolar quantities of IGF-I and IGF-II annihilated RGD-specific binding. IGFBP-2 binding at the cell surface led to dephosphorylation of the focal adhesion-kinase (FAK) of up to 37% (P<0.01), and of the p42/44 MAP-kinases of up to 40% (P<0.01). In addition, IGFBP-2 promoted de-adhesion of the cells dose-dependently by up to 30% (P<0.05), and reduced proliferation by 24% (P<0.01). Since one of the cell lines used does not express a functional IGF-I receptor, these data demonstrate that IGFBP-2 can act in an IGF-independent manner, at least in part by an interaction with alpha5beta1-integrin.

Genital skin fibroblasts (GF) of patients with androgen insensitivity syndrome express higher insulin-like growth factor binding protein (IGFBP)-2, -3 and -5 than GF of normally virilized males

BACKGROUND

We investigated the effects of androgens, estradiol (E2) and insulin-like growth factor (IGF)-I on IGF-II, insulin-like growth factor binding protein (IGFBP)-2, -3 and -5 and mRNA in genital fibroblasts (GF) from patients with complete androgen insensitivity (CAIS) and normally virilized males (C).

METHODS

Proteins were measured by specific RIA and Western ligand blot, and specific mRNA levels by RT-PCR normalized by GAPDH levels.

RESULTS

Secretion of IGF-II was lowered in CAIS (p<0.001) GF and by testosterone + IGF-I in C GF. Secretion of IGFBP-2 was higher (p<0.001) in CAIS GF and IGFBP-2 mRNA levels were increased by E2 in C GF (p<0.05). E2 stimulated IGFBP-2, -3 and -5 expression in CAIS GF. CAIS GF also secreted more IGFBP-3 (p<0.001) and accumulated 3-5 times more IGFBP-5 mRNA than C GF (p<0.001).

CONCLUSION

In contrast to C GF, the availability of IGF-II in CAIS GF is apparently decreased by two facts: by the decreased expression and by increased expression of IGFBP-2, -3 and -5. Furthermore, E2 and IGF-I modulate the expression of IGF-II and IGFBP in GF. This may play a role in the failure to develop male external genitals in CAIS patients.

Cortical bone density is normal in prepubertal children with growth hormone (GH) deficiency, but initially decreases during GH replacement due to early bone remodeling

Dual energy x-ray absorptiometry (DEXA) has revealed that GH- deficient adults gain in bone mineral density during GH therapy. Measurements of volumetric bone density (grams per cubic centimeter vs. grams per square centimeter) and structure, however, are achieved through peripheral quantitative computed tomography (pQCT). In 45 prepubertal GH-deficient children, we studied pQCT measurements before the start and for 12 months of GH treatment. Serum alkaline phosphatase (AP), procollagen I carboxyl-terminal propeptide (PICP), and deoxypyridinoline reflected bone metabolism status. Findings at the start of GH treatment were (mean SD score): bone area, -0.44; cortical density, -0.03; cortical area, -1.32; cortical thickness, -1.41; and marrow area, +0.66. At 12 months, cortical density had fallen to -0.73 (P < 0.001), whereas cortical area and thickness, and marrow area did not change. AP, PICP, and deoxypyridinoline increased significantly within the first 3 months (increase: AP, 66.5 U/liter; PICP, 72 microg/liter; DPD, 11.4 nmol/mmol creatinine). The pQCT showed that cortical density is not reduced in GH-deficient patients. Higher bone metabolism explains the lower cortical density after GH therapy commenced. Thus, the manifestation of GH deficiency is evidently similar in children and adults, and pQCT provides important information in addition to DEXA measurements, as DEXA does not take bone structure into account.

Measuring IGF-I, IGFBP-2 and IGFBP-3 from dried blood spots on filter paper is not only practical but also reliable

OBJECTIVE

The aim of this study is to adapt measurements of IGF-I, IGFBP-2 and IGFBP-3 to dried blood filter disk assays.

METHODS

Measurements of the three analytes in serum samples and in the corresponding blood spotted onto filter paper were compared by applying standard radioimmunoassays.

RESULTS

In paired experiments, the quantity of all antigens measured on dried filter spots showed an excellent correlation to that in serum (R>0.88) and in addition this correlation was independent of the whole blood hematocrit value. Recovery of IGF-I, IGFBP-2 and IGFBP-3 in experiments using recombinant standards mixed with whole blood was well correlated with the recovery of the plasma fraction on the filter paper. All of the blood spot assays showed a inter- and intra-assay variation of less than 10% and the blood spots were stable over a period of more than 5 months stored at -20 degrees C.

CONCLUSIONS

Taken together, these data clearly demonstrate that such a filter paper assay is a reliable procedure to monitor changes of IGF-I, IGFBP-2 and IGFBP-3 content in blood. The obvious advantages of this methods concerning storage, handling and shipping of blood probes helps to solve the logistics of centralised measurements of these three analytes.

Mixed gonadal dysgenesis and precocious puberty

A girl aged 5 years and 6 months presented with premature thelarche in our outpatient clinic. During long-term observation, we recorded growth acceleration, advanced bone age, and elevated oestradiol levels which together were taken to confirm the diagnosis of precocious puberty. The patient was successfully treated with a gonadotropin-releasing hormone agonist, but in view of the poor growth prognosis, recombinant human growth hormone was administered concurrently. At the age of 9 years and 6 months a mild clitoris enlargement and conspicuous muscle development without any further signs of virilization were noticed. Laboratory findings showed high values for testosterone and normal basal values for 17-hydroxyprogesterone and dehydroepinadrosterone sulphate. Explorative laparotomy revealed a gonadoblastoma arising from testicular structures on the left, a female streak gonad on the right side, and normal uterus and fallopian tubes. The karyotype was 46,XY/45,X. These findings confirmed the diagnosis of mixed gonadal dysgenesis with testosterone-producing gonadoblastoma.

Normal progression of testicular size in boys with idiopathic short stature and isolated growth hormone deficiency treated with growth hormone: experience from the KIGS

BACKGROUND

The aim of this retrospective analysis was to evaluate the effects of growth hormone (GH) treatment on testicular development in boys with idiopathic short stature (ISS) and isolated GH deficiency (IGHD) followed in the KIGS (Pharmacia International Growth Database).

METHODS

For inclusion in the study, the patients had to have received more than 1 year of prepubertal GH treatment, at least 4 consecutive years of GH treatment in total, and to have attained their final height, defined as a height velocity of less than 2 cm/year. Data on 107 boys in the KIGS database have been analyzed.

RESULTS

No significant differences in duration of GH treatment and testicular volume at the start of treatment or at final height were found between the boys with ISS and those with IGHD. The progression of testicular volume in boys with ISS or IGHD during GH treatment did not differ from the reference population.

CONCLUSIONS

This analysis shows that GH treatment does not alter testicular growth in boys with ISS or IGHD. However, prospective controlled studies are needed to rule out moderate attenuating or stimulating effects.

Isolated GH deficiency (IGHD) type II: imaging of the pituitary gland by magnetic resonance reveals characteristic differences in comparison with severe IGHD of unknown origin

OBJECTIVE

To determine the specific morphology of the pituitary gland in children with severe isolated GH deficiency due to GH-1 gene mutations (IGHD type II).

DESIGN

The pituitary gland morphology in magnetic resonance imaging (MRI) of children with IGHD type II was analyzed and compared with the findings in a group of children with comparably severe IGHD of unknown origin. In addition, the birth histories of both groups were studied.

SUBJECTS

Thirteen children with IGHD type II were diagnosed in seven European children's hospitals and they carried a corresponding GH-1 gene mutation. For comparison, we selected from a group of 66 MRI-studied GH-insufficient subjects diagnosed in our clinic, all children with severe IGHD (all GH peaks <4 microg/l) who had no GH-1 gene mutation, no first-grade relative with IGHD and no septo-optic dysplasia.

METHODS

Sagittal and coronal images of the brain were analyzed for the presence of any malformation of the pituitary gland and the intracranium. The height of each adenohypophysis was measured in a strict midline sagittal image for quantification of the gland's size. In addition, patients' files were reviewed for birth trauma or breech delivery.

RESULTS

Normal MRI morphology of the pituitary gland was observed in all patients of the familial IGHD type II group (P<0.003) in which, however, five of thirteen patients (38%) exhibited a mild hypoplasia of their gland (mean sagittal adenohypophysial height -1.0+/-0.03 SD score (SDS)). In contrast, the pituitary gland in the idiopathic group showed a definitive malformation with hypoplasia of pituitary stalk and adenohypophysis in all cases, while ectopia of the neurohypophysis was present in nine of the ten cases. The adenohypophysis was significantly smaller in the idiopathic group (mean sagittal adenohypophysial height -3.2+/-0.3 SDS) (P<0.0001). All thirteen birth histories in the familial group (IGHD type II) were unremarkable while, in the idiopathic group, three of eight available birth histories recorded a breech delivery or traumatic birth (37.5%) (P<0.05).

CONCLUSIONS

This study shows for the first time that MRI pituitary morphology may correlate with the etiology of severe IGHD: normal morphology suggests the presence of GH-1 gene mutations, while severe hypoplasia with malformation have other causes which might include so far unknown genetic defects as well as traumatic insults.

Adult height after GH therapy in 188 Ullrich-Turner syndrome patients: results of the German IGLU Follow-up Study 2001

OBJECTIVES

We aimed to evaluate the factors influencing true adult height (HT) after long-term (from 1987 to 2000) GH treatment in Ullrich-Turner syndrome (UTS) based on modalities conceived in the 1980s.

DESIGN

Out of 347 near-adult (>16 Years) patients from 96 German centres, whose longitudinal growth was documented within KIGS (Pharmacia International Growth Database), 188 (45, X=59%; bone age >15 Years) were available for further anthropometric measurements.

RESULTS

At a median GH dose of 0.88 (10th/90th percentiles: 0.47/1.06) IU/kg per week, a gain of 6.0 (-1.3/+13) cm above the projected adult height was recorded. Variables were recorded at GH start, after 1 Year GH, puberty onset, and last visit on GH therapy. At these visits, the median ages were 11.7, 12.7, 14.2, 16.6 and 18.7 Years; and median heights, 0.4, 1.1, 1.7, 1.7 and 1.3 SDS (UTS) respectively. Height gain (DeltaHT) after GH discontinuation was 1.5 cm. Total DeltaHT correlated (P<0.001) negatively with bone age and HT SDS at GH start, but positively with DeltaHT after the first Year, DeltaHT at puberty onset, and GH duration. Final HT correlated (P<0.001) positively with HT at GH start, first-Year DeltaHT, and HT at puberty onset. Body mass index increased slightly (P<0.05), with values at start and adult follow-up correlating highly (R=0.70, P<0.001). No major side effects of GH occurred.

CONCLUSIONS

GH dosages conceived in the 1980s are safe but too low for most UTS patients. HT gain and height are determined by age and HT at GH start. Height gain during the first Year on GH is indicative of overall height gain. After spontaneous or induced puberty, little gain in height occurs.

Malnutrition, zinc supplementation and catch-up growth: changes in insulin-like growth factor I, its binding proteins, bone formation and collagen turnover

OBJECTIVE

Zinc may be a limiting factor in restricting catch-up growth in severely malnourished children. This study had two aims: (i) to examine the effect of different zinc supplementation regimens on IGF-I, its binding proteins and on markers of bone and collagen turnover in severely malnourished children and (ii) to investigate mechanisms underlying catch-up growth by examining changes in these markers during nutritional rehabilitation, their inter-relationships and their relationships with ponderal and linear growth.

DESIGN

Double-blind randomized intervention study of three regimens of oral zinc supplementation.

PATIENTS

One hundred and forty-one children, aged 6-36 months, mean (SD) age 15.4 (8.7) months, with day 1 weight-for-height SD score (whz) -2.6 (0.93) and height-for-age SD score (haz) -3.79 (1.29).

MEASUREMENTS

Weight, height, lower leg length (by knemometry) at 15-day intervals from day 1 to day 90 of nutritional rehabilitation. Blood collection on days 1, 15 and 30 for IGF-I, IGFBP3, IGFBP2, bone alkaline phosphatase (BAP, osteoblast marker), procollagen type I C-terminal propeptide (PICP, marker of type I collagen synthesis), procollagen type III N-terminal propeptide (P3NP, marker of soft tissue type III collagen synthesis) and type I collagen telopeptide (ICTP, marker of type I collagen breakdown).

RESULTS

There was early rapid weight gain during refeeding, whereas height gain occurred later in the trial. IGF-I, IGFBP3, BAP, PICP and P3NP were low or very low on day 1 compared to well-nourished age-matched European children, and all increased within 15 days (P < 0.001), with PICP and P3NP reaching levels higher than European norms. IGFBP2 and ICTP were high on day 1 and decreased over the same period (P < 0.001). There were no differences in anthropometric outcome or marker responses among zinc regimens. Day 1 whz was correlated with BAP, PICP and P3NP (P < 0.001). Changes in IGF-I, IGFBP3, BAP, PICP and P3NP over 30 days correlated with ponderal growth (whz change) over the same period (all P < 0.01). However, changes in these markers over 30 days correlated better with lower leg growth (all P < 0.01) and linear growth (haz change, P < 0.01 for PICP and P3NP, P < 0.05 for IGFBP3) measured over 90 compared with 30 days. At most time points, there were strong positive correlations (i) among IGF-I, IGFBP3, BAP, PICP and P3NP (P < 0.01) and (ii) between IGFBP2 and ICTP (P < 0.01). Conversely, IGFBP2 was negatively correlated with IGF-I, IGFBP3, BAP, PICP and P3NP at most time points (P < 0.01).

CONCLUSIONS

We found no difference among zinc regimens in growth, IGF-I and its binding proteins or markers of bone and collagen turnover. Severe malnutrition was associated with low rates of bone and collagen synthesis and high rates of collagen degradation, and nutritional rehabilitation was associated with full or partial 'normalization' of the markers studied. Early weight gain and subsequent linear growth were associated with early increments in IGF-I, IGFBP3 and markers of bone and collagen formation. The study of these markers has provided additional insights into the mechanisms of the effects of malnutrition and refeeding on growth.

The metabolic effects of short-term administration of physiological versus high doses of GH therapy in GH deficient adults

OBJECTIVE

GH treatment has demonstrated favourable effects on most features of GH deficiency in hypopituitary adults. However, most studies employed supraphysiological GH doses, resulting in deterioration in insulin sensitivity (SI). The short-term metabolic effects of physiological doses of GH therapy in GH deficient (GHD) adults are largely unknown. We therefore compared the effects of short-term administration of two 'physiological' ('lowest' dose: 0.0017 mg/kg/day; 'low' dose: 0.0033 mg/kg/day) with two 'supraphy-siological' ('high' dose: 0.010 mg/kg/day; 'highest' dose: 0.025 mg/kg/day) GH doses on SI, beta-cell function, IGF-1 and IGFBPs -1 and -3 in a group of GHD adults.

PATIENTS AND METHODS

Thirteen GHD adults were recruited (seven men, aged 23-63 years). For each of the four doses, six patients (three men) were allocated randomly to undergo a 7-day treatment phase. Fasting blood samples were collected daily (days 1-8), and SI and beta-cell function were calculated using the homeostasis model assessment (HOMA).

RESULTS

All four GH doses increased IGF-1, IGFBP-3 and IGF-1/IGFBP-3 ratio, and decreased IGFBP-1 from day 3 onwards (P < 0.05). The highest dose increased fasting glucose (P < 0.001), insulin (P < 0.001) and beta-cell function (P < 0.001), but decreased SI (P < 0.001). The high and low doses did not modify fasting glucose and insulin, SI or beta-cell function, whereas the lowest dose enhanced beta-cell function (P < 0.05). The overall increase in the GH dose increased IGF-1, IGFBP-3, fasting glucose and insulin (P < 0.001), demonstrated a positive correlation with the final change in fasting glucose (r = 0.5, P < 0.05) and insulin (r = 0.8, P < 0.001) and a negative correlation with final SI (r = -0.5, P < 0.05).

CONCLUSIONS

Our results suggest that short-term administration of the highest GH dose induced insulin resistance, whereas the lowest dose (0.0017 mg/kg/day) could represent the optimal starting dose in GHD adults due to its beneficial effects on beta-cell function without compromising SI. It is, however, yet to be determined whether the positive effects of the lowest GH dose on beta-cell function can be demonstrated over a longer period of time.

Gene dosage analysis in Silver-Russell syndrome: use of quantitative competitive PCR and dual-color FISH to estimate the frequency of duplications in 7p11.2-p13

Silver-Russell syndrome (SRS) describes a heterogeneous malformation syndrome mainly characterized by intrauterine and postnatal growth retardation (IUGR/PNGR). Approximately 10% of SRS cases have been associated with maternal uniparental disomy (matUPD) 7. This suggests the involvement of at least one imprinted gene on chromosome 7 in the pathogenesis of SRS. Additionally, two familial and one single SRS patients have been published with an interstitial duplication in 7p11.2-p13, including the genes GRB10 and IGFBP1; IGFBP3 was investigated in only one case revealing duplication; conversely, double gene dosage of EGFR was excluded in all 3 patients. Two further cytogenetically abnormal cases, one with a paracentric inversion (7)(p14p12) and one with matUPD7/partial trisomy for 7p13-q11, confirmed that the proximal short arm of chromosome represents an interesting region possibly harboring (a) candidate gene(s) for SRS. Although previously published investigations on the genes GRB10, IGFBP1, IGFBP3, and EGFR report neither disease-relevant mutations nor abnormal imprinting patterns, the SRS cases with chromosomal duplications suggest that variation of gene copy number might be a further type of mutation. To obtain meaningful results on the frequency of duplications in proximal 7p, we screened 32 SRS patients using quantitative PCR assays for GRB10, IGFBP1, IGFBP3, and EGFR. The data were confirmed by dual-color fluorescence in situ hybridization (FISH) of spot check samples. Results obtained by both methods exclude duplications in all analyzed patients and indicate an overall percentage of duplication among SRS patients between 2.4% (GRB10) and 5% (IGFBP1). By testing and evaluating quantitative competitive PCR for various loci, we developed a practical approach for gene dosage analysis which can be easily established for routine purposes.

The potential of prediction models based on data from KIGS as tools to measure responsiveness to growth hormone. Pharmacia International Growth Database

Various prediction models have been developed, based on data documented within KIGS (Pharmacia International Growth Database), for use in the growth hormone (GH) treatment of children with short stature resulting from GH deficiency (GHD) or other causes. In addition to the practical value of such models as part of a 'forward strategy' guiding GH treatment, we now propose that prediction models may also be useful for the identification of individual variance in responsiveness. In a comparison involving 1,800 children with idiopathic GHD (IGHD), 151 children who acquired GHD after treatment for medulloblastoma and 192 children with GHD accompanying craniopharyngioma, it was shown that the responsiveness to GH of patients with craniopharyngioma equalled that of IGHD patients, whereas patients with medulloblastoma were less responsive. These observations and the identification of 'good' and 'poor' responders to GH have practical clinical consequences (e.g. modification of treatment), and will, in the future, lead to the identification of those factors which determine the variability of sensitivity to GH. This will improve the efficacy and safety of GH treatment as well as reducing the costs involved.

Relevance of IGF-I, IGFBP-3, and IGFBP-2 measurements during GH treatment of GH-deficient and non-GH-deficient children and adolescents

BACKGROUND

Little information is available on the relevance of parameters representing the insulin-like growth factor (IGF) system with regard to growth hormone (GH) treatment during childhood. In adults, high IGF-I levels were found to be associated with side effects and long-term risks.

AIM/METHOD

Our aim was to monitor the serum levels of IGF-I, IGF-binding protein (IGFBP) 3, and IGFBP-2 during long-term GH treatment of 156 patients with GH deficiency (GHD) and of 153 non-GHD patients. We determined the extent to which the IGF parameters exceed the normal ranges and identified those parameters which are predictive of 1st-year growth.

RESULTS

In prepubertal GHD children, the levels of IGF-I, IGFBP-3, and IGF-I/IGFBP-3 exceeded the 95th centile of the reference values for this age group in 2.3, 0.3, and 7.9% of the cases, respectively, whereas in prepubertal non-GHD children, the same parameters exceeded the 95th reference centile in 20.1, 3.5, and 32.2%, respectively. In pubertal GHD children IGF-I, IGFBP-3, and IGF-I/IGFBP-3 levels exceeded the 95th reference centile in 11.1, 1.5, and 15.4%, respectively. In pubertal non-GHD children, these levels also exceeded the 95th centile in 26.7, 7.0, and 41.4%, respectively. In both GHD and non-GHD groups, however, some patients had IGF parameters which were below the reference values. Our analysis showed that, in both groups, in addition to maximum GH, all IGF parameters (IGF-I, IGFBP-3, IGF-I/IGFBP-3 ratio, IGFBP-2 or derivatives) significantly extend the scope of a calculated model for predicting 1st-year height velocity.

CONCLUSION

For reasons of safety and optimization of GH therapy, it is essential to follow up IGF-I, IGFBP-3, and IGFBP-2 levels regularly during childhood.

Clinical and endocrine characteristics in atypical and classical growth hormone insensitivity syndrome

OBJECTIVE

Classical growth hormone insensitivity syndrome (GHIS) comprises a dysmorphic phenotype, extreme short stature (height SDS < 3), normal GH and low IGF-I and IGFBP-3. Wide clinical variation is recognised with classical and atypical forms. We aimed to delineate features of the milder "atypical" GHIS phenotype, and to determine whether this correlates with milder auxological and biochemical features.

METHODS

Fifty-nine patients from a European series of 82 patients with GHIS, with strict diagnostic criteria of GHIS, were studied and assigned to classical or atypical GHIS groups according to facial phenotype, i.e. "classical" required 2 of 3 recognized GHIS features (frontal bossing, mid-facial hypoplasia and depressed nasal bridge), "atypical" required 0 or 1 of these facial features. Classical and atypical GHIS groups were compared in terms of (1) phenotypic features, including high-pitched voice, sparse hair, blue sclera, hypoglycaemia, microphallus, (2) birth length, height SDS, and (3) basal IGF-I, IGF-II, IGFBP-1, IGFBP-3, GHBP and increase in IGF-I on IGF-I generation testing.

RESULTS

Fifty patients [24 males, 26 females, aged 8.6 +/- 4.6 years (mean +/- SD)] had "classical GHIS", 9 patients (7 males, 2 females, aged 7.8 +/- 4.1 years) had "atypical GHIS", 7 with normal facies. Atypical GHIS patients had lesser height deficit (Ht SDS -4.0 +/- 1.4) compared to classical GHIS (-6.7 +/- 1.4), less reduction in IGFBP-3 SDS (atypical -5.5 +/- 3.3; classical -8.6 +/- 2.4), and more had normal GHBP (>10% binding). Other variables were also less frequent in atypical GHIS patients: high-pitched voice 11% (70% classical), sparse hair 11% (42% classical), blue sclera 0% (38% classical), hypoglycaemia 11% (42% classical), and microphallus 14% (1 of 7 males), compared to 79% of classical (19 of 24 males).

CONCLUSIONS

Atypical GHIS patients, with relatively normal facial appearance, demonstrate less height defect and biochemical abnormalities compared to classical patients. GH insensitivity may be present in children with short stature and an otherwise normal appearance.

Varying clinical presentations at onset of type 1 diabetes mellitus in children--epidemiological evidence for different subtypes of the disease?

OBJECTIVE

On the basis of 2121 case observations between 1987 and 1997, we describe the clinical and laboratory characteristics of diabetes mellitus type 1 at its onset. Our objective is to analyze whether clinical presentation follows a uniform pattern or whether there is evidence for different subtypes.

RESEARCH DESIGN AND METHODS

Thirty-one pediatric hospitals and one diabetes center in Baden-Wuerttemberg (BW), Germany, participated in this study. The hospital records of 2121 children below 15 yr of age were examined retrospectively. Statistical analysis was done after logarithmic transformation into a normal distribution.

RESULTS

The average duration of symptoms was found to be 15.2 d (95% CI (Confidence Intervals) = 14.3-16.1) ranging between 2.0 and 180 d (95% central range). The most frequent symptoms were polyuria and polydipsia; 7.2% presented with altered level of consciousness. The mean blood glucose value was 407.9 mg/dL (95% CI = 400.0-416.0), corresponding to 23.3 mmol/L (95% CI = 22.8-23.8). The median pH value was 7.35 (95% CI = 7.34-7.36), and the median base excess was -5 mmol/L (95% CI =-5 to -4). The younger patients had a shorter duration of symptoms and suffered most frequently from ketoacidosis.

CONCLUSIONS

Although the symptoms of diabetes at its onset follow a uniform pattern, the clinical presentation and duration of symptoms indicate that there may be various forms of type 1 diabetes.

Radiological signs of Leri-Weill dyschondrosteosis in Turner syndrome

BACKGROUND/AIMS

Leri-Weill dyschondrosteosis (LWD), a mesomelic short stature syndrome with Madelung deformity, was recently reported to be caused by SHOX (short stature homeobox-containing gene) haploinsufficiency. The loss of SHOX on Xp22.32, also called PHOG (pseudoautosomal homeobox-containing osteogenic gene), through structural aberrations of the X chromosome was also implicated in the short stature phenotype and some additional stigmata of Turner syndrome. The aim of this study was to systematically examine left-hand radiographs from Turner girls for the presence of signs of LWD.

METHODS

We retrospectively studied 168 left-hand radiographs from 54 patients with Turner syndrome (bone age >10.5 years) who were treated with rhGH and seen during the last 10 years in our clinic. For comparison, we analyzed 7 radiographs from 5 patients with LWD and 52 radiographs from 20 patients with GH deficiency. The shape of the distal radial epiphysis (triangularisation index = TI) and the carpal angle were quantitatively measured. In addition, we screened for the presence of a premature cleft fusion or an ulnar deviation of the articular surface of the distal radial epiphysis and for fourth metacarpal shortening. One of 54 Turner girls (2%) was affected with LWD and presented with Madelung deformity.

RESULTS

No milder forms of Madelung deformity were detected. However, there was a significant trend to a triangular shape of the distal radial epiphysis in Turner syndrome: the median TI was 2.7 in normal controls (range 1.8-3.7), 3.1 in Turner girls (range 2.0-6.3) (p < 0.001 against controls), and 6.0 in patients with LWD (range 3.5-11.0) (p < 0.001 against controls).

CONCLUSIONS

The triangularisation index did not correlate with the carpal angle (median 122.5

Reference intervals from birth to adulthood for serum thyroxine (T4), triiodothyronine (T3), free T3, free T4, thyroxine binding globulin (TBG) and thyrotropin (TSH)

Disorders in thyroid function can impair normal development in children. Therefore it was our aim to establish reference intervals for serum triiodothyronine (T3), free T3 (fT3), thyroxine (T4), free T4 (fT4), thyroxine binding globulin (TBG) and thyrotropin (TSH) which are applicable from birth to adulthood by using the non-isotopic automated chemiluminescence immunoassay system, Immulite (DPC Los Angeles, USA). Serum samples from 762 euthyroid newborns, children and adolescents (369 female, 393 male; age 1 day to 19 years) were examined; of these, 381 were classified as pubertal. Due to non-normal distribution, the 2.5th, 50th and 97.5th percentiles (the central 95% interval) were calculated for each group. The median concentrations of T4, fT4 and TSH were up to 3.2-fold higher during the first 2 weeks, while T4 increased during the first month of life. The concentrations in all age groups showed no sex differences. From 1 year onwards, the concentration of all parameters tended to decrease until adult age, with the exception of TBG which increased by >60% (p<0.02) and reached a maximum at approximately 5 years of age. The findings underscore the fact that thyroid hormones are not associated with sexual development, except for TBG, which decreased slightly (p<0.04) between Tanner stages 1 and 5. However, the reference intervals established here demonstrate that marked changes occur in concentrations of thyroid hormones after the neonatal period. Our findings complement these of earlier studies. The developed reference intervals can be used to assess the thyroid status of patients, particularly if the measurements are done on the Immulite/Immulite 2000 system.

Diabetes incidence in children of different nationalities: an epidemiological approach to the pathogenesis of diabetes

AIMS/HYPOTHESIS

Incidence studies of children with Type I (insulin-dependent) diabetes mellitus and different ethnic backgrounds are known to provide important insights into the pathogenesis of the disease. For this reason, we compared the incidence rate in Baden-Württemberg, Germany, of children who were not of German descent with that of German children as well as with the reported incidence rates pertaining to the countries of origin of the children who were not of German descent.

METHODS

Our study was based on the Baden-Württemberg incidence register, part of the EURODIAB TIGER network, which includes 2,121 children aged 0-14 years, diagnosed as having Type I diabetes between 1987 and 1997. The study covered a population at risk of 1.8 million children, which represents 13.3% of the total number of children in Germany.

RESULTS

The total incidence rate was found to be 12.5 per 100,000 per year (95 %-CI 12.0-13.0); for German children alone it was calculated as 13.5 (95%-CI 12.9-14.1) and for children who were not of German descent it was significantly lower at 6.9 per 100,000 per year (95%-CI 5.8-8.0). The percentage of children who were not of German descent with Type I diabetes (8.3 %) is smaller than that among the general population (15.2%). Children from former Yugoslavia, Italy and Greece had incidence rates closer to their countries of origin than to the incidence rate of German children.

CONCLUSION/INTERPRETATION

Our findings indicate that genetic factors play a predominant role in the pathogenesis of Type I diabetes. However, the influence of certain aspects of life-style, which remain constant even after immigration, cannot be excluded.

Decreased expression of IGF-II and its binding protein, IGF-binding protein-2, in genital skin fibroblasts of patients with complete androgen insensitivity syndrome compared with normally virilized males

The action of androgen by way of the AR is required for the development of male gonads and external genitalia. The interplay between androgens and the somatotropic axis, in particular the IGFs in sexual development, is currently under thorough investigation. The IGF system is thought to mediate the androgen action in androgen-responsive cells. To investigate the interaction of androgens with the IGF system, we compared the expression of IGFs and IGF-binding proteins in cultured genital skin fibroblasts from nine patients with the syndrome of complete androgen insensitivity with that in genital skin fibroblasts from 10 normally virilized males. Mutations in the AR gene and/or abnormalities of the AR protein in the immunoblot were detected in all complete androgen insensitivity genital skin fibroblast strains. They caused a complete failure of DHT binding. RIA and RT-PCR demonstrated that the genital skin fibroblast strains expressed IGF-II, IGF-binding protein-2, and IGF-binding protein-3, but no IGF-I. Most strikingly, complete androgen insensitivity genital skin fibroblast strains produced significantly lower IGF-II (P < 0.001; 42.2 +/- 9.7 vs. 106.9 +/- 11.8 ng/mg protein) and IGF-II mRNA (P < 0.01, by RT-PCR) than control genital skin fibroblast strains. The production of IGF-binding protein-2 was also decreased (P < 0.03) in complete androgen insensitivity genital skin fibroblasts, whereas that of IGF-binding protein-3 did not differ. Furthermore, high levels of IGF-binding protein-5 mRNA were detected in all genital skin fibroblast strains, whereby the 28-kDa band in the ligand blot, probably representing IGF-binding protein-5, was more abundant in complete androgen insensitivity genital skin fibroblasts. Exposure of the genital skin fibroblasts to T (5 x 10(-8) M) had only weak effects on the expression of IGFs and IGF-binding proteins. In conclusion, although the mechanism underlying these differences requires further study, it is conceivable that in addition to the endocrine actions of IGF-I, IGF-II and IGF-binding protein-2, as local growth factors, are involved in the mediation of androgen action and growth of genital tissues.