Adult height and epigenotype in children with Silver-Russell syndrome treated with GH

AIMS

To compare adult heights of GH-treated and GH-untreated patients with Silver-Russell syndrome (SRS) who were epigenotyped.

METHODS

This was a nonrandomized retrospective study with matched controls at a single center. Molecular analysis of 32 out of 37 GH-treated patients (16 females) revealed IGF2-H19 epimutations in 12 and maternal uniparental disomy of chromosome 7 (matUPD7) in 5 patients; 15 were negative. At start of GH, mean age was 7.2 years and mean height -3.34 standard deviation score (SDS). Mean GH dose used was 51 µg/kg·day, mean duration of therapy was 5.6 years. Puberty was blocked by GnRH analogs in 16 patients. The untreated group comprised 13 individuals (5 females, mean age 6.8 years and mean height -3.34 SDS). End points were adult height and overall height gain.

RESULTS

GH-treated patients reached an adult height of -2.12 ± 0.98 SDS gaining 1.22 SDS in comparison to baseline. Adult height SDS of the untreated was -3.13 ± 1.37 SDS. The matched treated patients were significantly taller than their untreated counterparts. Outcome was dependent on height at start of GH and duration of therapy. Height gain was highest in the shortest patients.

CONCLUSIONS

GH improved adult height in SRS to a comparable degree as reported in nonsyndromic SGA children. A trend toward a better outcome in matUPD7 needs confirmation in larger cohorts.

Variants of the FTO gene in obese children and their impact on body composition and metabolism before and after lifestyle intervention

OBJECTIVE

To investigate the impact of variants of the FTO gene (rs1421085, rs17817449, rs9939609) in obese children before and after lifestyle intervention.

METHOD

DESIGN

Longitudinal, clinical intervention study with an increase in physical activity, and nutritional recommendations based on the 'Optimized Mixed Diet for German Children and Adolescents' (Research Institute of Child Nutrition, Germany).

STUDY POPULATION

75 overweight children (40 male, mean BMI 30.4±5.5 kg/m², mean age 12.6±2.6 years).

MEASUREMENTS

Genotyping by means of a TaqMan SNP genotyping assay. Lean and fat mass were determined by means of DXA.

RESULTS

For the whole study population, the 6-month lifestyle intervention resulted in a significant improvement (before intervention minus time point 6 months; mean±SD) in BMI-SDS (0.10±0.17, p<0.001), HOMA (1.41±3.19, p<0.001) and relative fat-mass-SDS (0.09±0.23, p=0.005). Before and after lifestyle intervention, there was no significant difference between heterozygote (n=52) and homozygote (n=21) carriers of the FTO gene in terms of BMI, body composition, and the metabolic profile (Insulin, HOMA, lipids, liver function tests).

CONCLUSION

Variants in the FTO gene are common in obese children but have no impact on body composition and metabolism before and after lifestyle intervention.

Short children with low birth weight born either small for gestational age or average for gestational age show similar growth response and changes in insulin-like growth factor-1 to growth hormone treatment during the first prepubertal year

BACKGROUND/AIMS

Growth hormone (GH) is an accepted treatment for short children born small for gestational age (SGA). The aim of this analysis was to compare the growth response to GH in children with low birth weight born SGA or appropriate for gestational age (AGA).

METHODS

This retrospective observational study is from one center. Of all the children with a birth weight <2,500 g treated, 50 were primarily diagnosed as having growth hormone deficiency ([A] SGA, n = 26; [B] AGA, n = 24) and 138 were originally diagnosed SGA or AGA (reclassified: [C] SGA, n = 102; [D] AGA, n = 36).

RESULTS

[Median; A, B, C, D]: at an age of 4.9, 5.2, 5.8, 5.8 years, a height of -2.9, -2.4, -2.8, -2.9 SDS and a GH dose of 27, 28, 41, 39 μg/kg/day, the children grew 0.9, 0.9, 0.8, 0.9 SDS in height, respectively. Insulin-like growth factor-1 (IGF-1) at GH start was, respectively, -2.1, -2.2, -0.4, -0.9 SDS and rose to (delta IGF-1) 1.8, 2.0, 1.7, 1.5 SDS during the first year on GH. All differences were not significant.

CONCLUSIONS

We show for the first time that short stature children with low birth weight born AGA experience the same increase in height and IGFs to GH treatment as those born SGA irrespective of actual GH secretory status.

Analysis of the GH content within archived dried blood spots of newborn screening cards from children diagnosed with growth hormone deficiency after the neonatal period

OBJECTIVE

It is unknown whether GH secretion of children with growth hormone deficiency (GHD) is already diminished at birth. We aimed to determine the GH content within archived dried blood spots of newborn screening cards from children diagnosed with GHD at childhood.

DESIGN

At our hospital, all children with the diagnosis of GHD and an actual age <10years were identified. For 16 patients (mean age, 7.4years; range, 1.0-9.7), screening cards were available. The archived dried blood from the first 48 to 96h of life was eluated in buffer of a highly sensitive hGH-ELISA to measure the GH content. Reference values were calculated based on 600 anonymous newborn screening cards of different ages.

RESULTS

Median GH content within the archived dried blood spots of the reference had declined by 30% during the first year and by further 35% during the next 8.5years of storage. After correction for time of storage, four out of the 16 archived dried blood spots of the GHD children contained low amounts of GH (≤5th percentile). Diminished GH secretion at birth was absent in isolated GHD, but associated with multiple pituitary hormone deficiency (MPHD) (P=0.0013), ectopic neurohypophysis (P=0.0013), lower GH test peak values (P=0.02) and higher weight at diagnosis (P=0.015).

CONCLUSIONS

Children with isolated GHD have normal GH secretory capacity during the first week of life while the majority of children with MPHD and pituitary malformation were GH deficient immediately after birth.

Auxology-based cut-off values for biochemical testing of GH secretion in childhood

OBJECTIVE

The diagnosis of GH deficiency (GHD) in childhood requires GH tests with arbitrary cut-offs. We aimed to define GH cut-offs based on auxology.

DESIGN

From a total of 349 children diagnosed with GHD between 1985 and 2005 at our hospital, we excluded all children who had additional characteristics likely to interfere with growth velocity. Age at start of therapy was defined as 4 to 8/9 years (girls/boys). Auxological inclusion criteria were pathological growth velocity, height at start of therapy >1.5 SD below the target, and efficient catch-up growth during GH therapy. Basal IGF-I/IGFBP-3, GH response to arginine and spontaneous GH secretion at night had been measured by the same polyclonal RIA. The reference was a group of 108 normally growing age-matched children with Turner syndrome or born small for gestational age tested during the same time period.

RESULTS

We identified 52 children with GHD who fulfilled the inclusion criteria. ROC analysis showed the best diagnostic accuracy at a peak GH cut-off for arginine of 6.6 μg/L (sensitivity, 84.3%; specificity, 75.5%; AUC=0.83) and at a peak GH cut-off during spontaneous secretion at night of 7.3 μg/L (sensitivity, 96.8%; specificity, 82.4%; AUC=0.93). Our arbitrarily defined GH cut-offs had been higher. Children diagnosed with GHD in the past with GH test values above the new cut-offs were less responsive to GH therapy (P=0.007).

CONCLUSIONS

Here we provide a new rational approach which allows the substitution of arbitrarily defined GH cut-offs by those based on auxology.

Investigation of myostatin serum levels before and after a 6-month lifestyle intervention program in obese children

OBJECTIVE

To investigate the relationship between myostatin serum levels and muscle mass, fat mass and HOMA before and after a 6-month lifestyle intervention program in obese children and adolescents.

DESIGN

A total of 57 overweight children and adolescents (female, n=27; age range, 6.0-16.1 years) were examined between 2007 and 2009. Mean BMI (±SD) was 31.1 (5.7) kg/m(2) corresponding to a mean BMI-SDS LMS of 2.2 (0.4). Muscle and fat mass were determined by means of DXA. Serum myostatin was measured by using a competitive ELISA. RESULTS [MEAN±SD]: After the 6-month intervention program, muscle mass (+2.1±2.7 kg, p<0.0001), and percentage myostatin serum levels (+23.7±26.7%, p<0.0001) were higher than before, whereas decreases in BMI (-0.4 kg/m(2)±1.5, p<0.0001), fat mass (-1.2±3.9 kg, p<0.0001), and HOMA insulin sensitivity index (-0.78±3.28 SD, p=0.0004) were observed. In 86% (n=49, p<0.0001) of all cases, the intervention program resulted in a higher level of myostatin. After lifestyle intervention, patients with the greatest increase of myostatin had a significantly lower increase of muscle mass (p=0.048) but did not differ for fat mass. There was no significant correlation between Myostatin and HOMA insulin sensitivity index before and after lifestyle intervention.

CONCLUSION

Both muscle mass and serum myostatin increased concordantly. Patients with the greatest rise of myostatin had a significantly lower increase of muscle mass suggesting a negative feedback loop between myostatin and muscle tissue. In our study, the change of myostatin serum levels was not associated with the amount of fat mass or HOMA insulin sensitivity index.

[Waiting time for and length of physicianc's consultation define the patient-physician interaction: results of a prospective study in 478 patients with chronic viral hepatitis]

BACKGROUND

Little is known about the physician-patient interaction in hepatitis B and C.

METHODS

This study by the federal competence network hepatitis analysed the physician-patient interaction using the validated FAPI questionnaire. The questionnaire also contained questions concerning demography and disease characteristics. Of the total 1500 questionnaires sent out, 478 were returned (32 %) (20 % HBV vs. 80 % HCV).

RESULTS

The FAPI index of patients with HBV/HCV infection (3.10 +/- 0,99) was lower than that in patients with other internal medicine diseases (3.61 +/- 0.92; n = 148). Women had lower values than men (2.98 vs. 3.25; p = 0.005). Patients with active HBV infection showed higher values than those with HCV infection (3.27 vs. 2.97; p < 0.05). Patients with successfully treated hepatitis B/C had higher values than those with active disease (3.36 vs. 3.02; p = 0.004). The index was lower in patients who waited > 2 weeks for the consultation when compared to those with a shorter wait (2.92 vs. 3.31; p < 0.001) and was also lower in patients who waited > 30 min at the consultation day when compared to those with a shorter wait (2.81 vs. 3.39; p < 0.001). The index gradually increased with the consultation length (2.47 < 10 min vs. 2.79 10 - 15 min vs. 3.21 15 - 30 min vs. 3.82 > 30 min; p < 0.001). The index was higher in patients seen by gastroenterologists (3.43) when compared with general practioners (3.10), internists (3.02) and clinical settings (3.13) (p < 0.05). A good information status was associated with higher FAPI values when compared with a bad information status (3.43 vs. 2.76; p < 0.001). Fibrosis, health insurance and age were not associated with FAPI index (p > 0.2). By multivariate analysis a long consultation, a good information status, patients' patience, short waiting times, and providing contact to a patient support group were independently associated with a high index.

CONCLUSIONS

The physician-patient interaction in chronic viral hepatitis is worse than in other internal medicine diseases with problems being more pronounced in HCV infection and women when compared to men and HBV infection. Short waiting times and patients' patience ameliorated the interaction as well as the consultation length, the information status of the patient and providing contact to a patient support group. Type of health insurance did not affect either waiting times or physician-patient interaction; thus there is no hint for a two-class medicine in this part of hepatology.

Prevalence and incidence of endocrine disorders in children: results of a survey in Baden-Wuerttemberg and Bavaria (EndoPrIn BB) 2000-2001

BACKGROUND

Sparse data is available on the incidence of endocrine disorders among children in Germany.

AIM

A pioneer study was established to analyse, in the German states of Baden-Wuerttemberg (BW) and Bavaria (BY), the incidence and prevalence of congenital adrenal hyperplasia (AGS; CAH), precocious puberty (PP), primary congenital hypothyreosis (PCH), Graves disease (MB), and growth disorders related to the Ullrich-Turner syndrome (UTS) and growth hormone deficiency (GHD).

METHODS

Participation in the study involved each paediatric hospital in BW and BY (n = 63),and all regional paediatricians belonging to the Association of Statutory Health Insurance Physicians (SHI) practising in these states (n = 1 443). Data collection was done from January 1, 2000, to December 31, 2001, and included all patients in the 0- < 18 age range.

RESULTS

Completeness of data was 81 % for CAH and 55 % for UTS (capture-mark-recapture method).The incidence rate (IR, per 100 000 / year)versus prevalence rate (per 100 000 at the time point December 31, 2001) was: CAH 0.64 vs.9.60; PP 2.42 vs. 10,85; PCH 1.88 vs. 14.97; MB 0.89 vs. 3.25; UTS 2.15 vs. 29.07; and GHD 3.47(IR). Among neonates, the incidence of CAH was 1 / 7 794; PCH 1 / 2 629 and UTS 1 / 2 300.

CONCLUSIONS

A pioneer study has been established in Germany for investigating the frequency of AGS (CAH), PP, PCH, MB, UTS, and GHD among children and adolescents. Our data shows that these disorders occur in approx. 2,700 children per year in total Germany, and about 12 000 of these children need to be treated in specialized paediatric endocrinological centres.

Follow-up of adolescents with diabetes after transition from paediatric to adult care: results of a 10-year prospective study

OBJECTIVE

Our main objective in this study was to identify the type of clinical care received by young type 1 diabetic patients who have made the transition from paediatric to adult care, and to assess the metabolic status of long-term treatment after the transition.

METHODS

A standardized questionnaire was used prospectively to follow 99 patients with type 1 diabetes mellitus after their transition to adult care. This survey was done once a year, from 1998 to 2008.

RESULTS

Directly after transition from paediatric care 38.4% of patients were found at specialised outpatient units; whereas 41.1% received care at a diabetes centre and 20.5% were monitored by general practitioners or specialists in internal medicine. Five-year results showed that 25.0% had continued to visit an outpatient unit; 41.7% were still visiting a diabetes centre; and 33.3% had remained in the care of general practitioners or internal specialists. We observed a trend showing slight improvements in the HbA1c values over time, however no major changes in metabolic control were observed after transition.

CONCLUSIONS

Transition marks a critical phase for young, diabetic patients as they may frequently switch from one physician or centre to another. The individual optimization of therapy, established during paediatric care, provides the decisive groundwork for disease control in young adults.

Musculoskeletal abnormalities in juvenile idiopathic arthritis--a 4-year longitudinal study

OBJECTIVES

Bone density in juvenile idiopathic arthritis (JIA) is largely normal whereas geometric parameters of bone are abnormal. The most prominent changes are a reduction in muscle cross sectional area (CSA) and muscle force. The aim of this study was to assess the evolution of these changes throughout the course of the disease.

METHODS

Twenty-five JIA patients were assessed by peripheral quantitative computed tomography longitudinally with a median of 48 months between measurements. At the non-dominant forearm, parameters of bone density and geometry as well as muscle CSA were recorded. The strength-strain index (SSI) as an indicator of bone strength was determined.

RESULTS

Muscle CSA improved from a median Z-score of -1.94 to -1.10 at follow-up. Cortical thickness increased from -1.55 to -0.97 whereas marrow area remained enlarged at 0.96 vs 1.05. Cortical density remained normal at 0.34 vs 0.69 and trabecular density improved from -0.75 to -0.36. The SSI increased from -0.79 to -0.13.

CONCLUSIONS

JIA patients show some improvement in muscle CSA and an increase in cortical thickness. The marrow area remains enlarged but by increasing the cortical thickness, area and diameter, bone strength increases. These geometric adaptations, for the first time shown in this study, nevertheless represent a disturbance in skeletal development. In addition to efficient disease control, training modalities to improve muscle strength and subsequent bone development have to be included in therapeutic approaches.

The d3-growth hormone (GH) receptor polymorphism is associated with increased responsiveness to GH in Turner syndrome and short small-for-gestational-age children

CONTEXT

A protein polymorphism of the GH receptor (GHR) based on the genomic deletion of exon 3 (d3-GHR) has recently been linked to the magnitude of growth response to high-dose recombinant human GH (rhGH) therapy of short children without GH deficiency.

OBJECTIVE

This study tests the novel association in two distinct groups of rhGH-treated patients, short girls with Turner syndrome and short children born small for gestational age (SGA).

DESIGN

The retrospective study included all children who were treated with rhGH during the last 18 yr at our hospital.

PATIENTS

Patients with Turner syndrome were defined by the specific karyotype (n = 53), short children born SGA were determined by birth length and/or weight less than -2.0 sd score and a height at start of rhGH therapy less than -2.0 sd score (n = 60). Exclusion criteria were puberty, an age less than 3.5 or more than 14 yr, and GH deficiency.

MATERIALS AND METHODS

Growth prediction for the first year of therapy was calculated on the basis of rhGH dose, age, weight, height, and gender-adjusted midparental height according to the prediction models by Ranke et al. The GHR-exon 3 locus was genotyped using a PCR multiplex assay. GH, IGF-I, and IGF binding protein 3 (IGFBP-3) were measured by RIA.

INTERVENTION

For growth promotion, a mean rhGH dose of 38 mug/kg.d (sd, +/-8) was administered in Turner syndrome patients and 56 mug/kg.d (sd, +/-11) in short children born SGA.

RESULTS

No significant difference in height, spontaneous height velocity, IGF-I, and IGFBP-3 levels was found at the start of rhGH therapy in the three GHR genotype groups studied. At the first year of treatment, girls with Turner syndrome carrying one or two d3-GHR alleles showed a significantly higher increment in height velocity (P = 0.019) and exceeded their growth prediction significantly (P = 0.007), whereas their increments of IGF-I and IGFBP-3, weight, and height were not significantly different. Carriers of d3-GHR in the group of short children born SGA grew significantly faster than predicted (P = 0.023). However, in comparison to the carriers of full-length GHR, gain of height velocity was not significantly higher (P = 0.067). The mean gain of height associated with d3-GHR accounted for approximately 0.75 cm in SGA and 1.5 cm in Turner syndrome during the first year of rhGH therapy.

CONCLUSIONS

Our data support the theory that there is increased responsiveness to high-dose rhGH in association with the d3-GHR genotype. The magnitude of this effect may depend on the primary origin of the short stature.

Dominant transmission of prepubertal gynecomastia due to serum estrone excess: hormonal, biochemical, and genetic analysis in a large kindred

Increased extraglandular aromatization has been reported to cause the rare entity of familial gynecomastia. Recently heterozygous inversions at the p450 aromatase gene promotor locus were detected in two different families with this syndrome. We studied a family in which seven affected males over three generations had inherited prepubertal gynecomastia in an autosomal dominant manner. The proband developed gynecomastia at 11.5 yr, entered puberty at 12.5 yr, but was incompletely virilized at 19 yr. A similar development was observed in his affected stepbrother and one first-degree cousin. All three boys had acceleration of prepubertal growth and bone age. The older two had a diminished pubertal growth spurt and precocious growth arrest, but their final heights were within the range of their target height. In addition, the maternal grandfather and three maternal uncles were affected, who all had been mastectomized. The mother of the proband had normal age at menarche and no macromastia. Estrone levels of the proband and the other affected boys were elevated, 17beta-estradiol levels were high-normal, and testosterone levels were low. Hormonal analyses of the affected adults, who had all fathered children, revealed pathologically low serum testosterone levels but normal to high-normal levels of estradiol and estrone. The mother of the proband had elevated estrone levels. Treatment of the proband was more effective with anastrozole than with testolactone and increased the initially reduced testes volume to normal size, promoted virilization, and normalized serum estrone and testosterone levels. Neither preadipocytes from breast fat tissue of the affected stepbrother nor peripheral lymphocytes of the affected boys exhibited increased aromatase activity in culture. Therefore, these cells can be excluded from being the source of estrone excess. In addition, serum of the proband and his stepbrother did not contain factors promoting aromatase activity as assayed using preadipocytes from control individuals.A repeat polymorphism of the p450 aromatase gene cosegregated with the disease phenotype in the family, making a mutation of the p450 aromatase gene likely. Single-strand conformational polymorphism analysis of the known alternative untranslated exons and all coding exons of the p450 aromatase gene did not indicate any mutation. In addition, fluorescent in situ hybridization analysis using four probes covering the promotor region did not reveal the presence of any major inversion at this locus. In conclusion, preadipocytes and blood cells were excluded as the cell source of increased aromatization. Fluorescent in situ hybridization and single-strand conformational polymorphism analyses did not reveal any mutation of the p450 aromatase gene, but an intragenic polymorphic marker cosegregated with the disease phenotype. Excess of serum estrone in the presence of normal 17beta-estradiol levels may be the only indicative serum parameter of this mild manifestation of aromatase excess syndrome, which includes prepubertal gynecomastia and moderate hypogonadism in men but not necessarily short stature. In women, this mode of aromatase excess may remain clinically inapparent.

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.

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.

Dynamic organization of the somatosensory cortex induced by motor activity

Intensive and long-lasting experience of altered sensory input induces permanent changes in the functional organization of the somatosensory cortex. In addition, an increasing body of evidence suggests the existence of dynamic, short-term and task-dependent adaptation of representational maps within somatosensory cortex. It is hypothesized that somatosensory maps can, not only, be acquired within a short period of time, but might also be set up during periods of training related to specific tasks and subsequently activated dynamically upon performance of that particular task. In order to test this hypothesis we studied the functional organization of somatosensory cortex for a heavily overlearned and frequently performed task for which no new acquisition of a sensory map had to be assumed. To this end, the functional organization of somatosensory cortex for handwriting was compared with the organization during rest in healthy humans. Functional organization of the somatosensory cortex was assessed using non-invasive, neuromagnetic source imaging based on tactile stimulation of the thumb (D1) and little finger (D5) during writing and rest. In different blocks, subjects wrote with their right, dominant and their left hand, respectively. During writing, D1 and D5 of the writing hand were stimulated. To test the reliability of our results all measurements were repeated after 1 week. It was found that amplitudes of somatosensory evoked magnetic fields with latencies of 45 ms were reduced during writing compared with rest. This finding is in accordance with the sensorimotor gating effect. Using source localization we could show that cortical representations of D1 and D5 are more distant during writing with either hand compared with rest. Our data suggest that somatosensory cortical maps undergo rapid modulation depending on task-specific involvement of sensory processing in daily-life overlearned movements. As it is unlikely that a new sensory map is always acquired when a frequently used task such as writing is performed, we suggest that somatosensory cortex switches between different, concurrently pre-existing maps depending on actual requirements. Task-dependent activation of pre-existing maps might be a powerful mechanism to optimize stimulus processing.

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

The distribution of mislocalizations across fingers demonstrates training-induced neuroplastic changes in somatosensory cortex

The somatosensory system has been shown to alter its cortical activation patterns in reaction to changes in the attended sensory input to certain body parts. Whether these modifications in the functional organization of the somatosensory cortex of humans also result in perceptual changes has rarely been investigated. Here we used near-threshold tactile stimuli to the center of the fingertips to evoke mislocalizations to fingers other than the stimulated. In healthy untrained subjects, the distribution of the mislocalizations from each of the fingers was different from a distribution expected if the subjects were purely guessing the position of the stimulus. The digits next to the stimulated one receive a higher number of mislocalizations than digits further away from the stimulated digits. This decrease can be accounted for by digit-overlapping receptive fields in combination with the sequential representation of the digits in the primary somatosensory cortex. In a second experiment subjects received 20 h of simultaneous stimulation of the left thumb and little finger in the context of a perceptual task. For both hands, the distribution of mislocalization from these fingers was analyzed at the beginning and the end of the training. For the left hand, the number of assigned mislocalizations to the most distant neighbor digit (i.e., the simultaneously stimulated digit in the training) increased while the number of mislocalizations toward the direct neighboring digit decreased with the training. This change did not occur in the untrained right hand, or in the untrained subjects. We conclude that the distribution of mislocalization to fingers other than the stimulated can be used to investigate perceptual changes paralleling training-induced modifications in the activation patterns of the somatosensory cortex.

Significance of basal IGF-I, IGFBP-3 and IGFBP-2 measurements in the diagnostics of short stature in children

The role of IGF-I and IGFBP-3 measurements in the diagnostic work-up of short children is established but remains controversial. Little information exists on the value of IGFBP-2 measurements. Based on reference data established in 388 children we have reinvestigated the issue, using data from 392 short children who underwent the same diagnostic procedures between 1987 and 1998 (GHD, n = 187; non-GHD, n = 205, including patients with ISS, n = 76; IUGR, n = 46; and TS, n = 83). In comparing IGF-I, IGFBP-3 and IGFBP-2 serum levels of GHD and ISS children with reference data, we calculated the sensitivity, specificity, efficiency and positive predictive value for the diagnosis of GHD. The overall sensitivity of the parameters was high, the rank order being as follows: IGF-I >IGFBP-3 >IGFBP-2 (75, 67 and 62%, respectively). In contrast, the specificity was relatively low: IGFBP-3 >IGFBP-2 >IGF-I (50, 50 and 32%, respectively). The efficiency and positive predictive value of parameters was in the order of 40, 60 and 70--80%, respectively. In repeated measurements, the recorded basal levels of IGF-I and IGFBP-3 showed an overall narrow range of variation. We conclude that the determination of basal IGF parameters is, together with anthropometry and imaging techniques, an indispensable tool for differentiating between GHD and ISS; and that IGFBP-2 plays an additional role in this process.

Distribution of mislocalizations of tactile stimuli on the fingers of the human hand

Sensitivity of the fingers of the two hands to faint tactile stimuli were tested in eight healthy subjects with a von Frey hair in a forced choice point localization test. Frequencies of correct responses were higher on the left than on the right hand, consistent with a right hemispheric advantage for spatial processing. Within the hands, stimulations of the ring fingers resulted in the highest percentage of correct localizations and stimulations of the thumbs in the fewest correct responses. This superiority of the ring fingers is probably related to a higher point pressure sensitivity and does not reflect the relative size of the representational area of the different fingers in the somatosensory cortex. Mislocalizations, i.e., stimuli that were not correctly attributed to the stimulation site, were located in the vicinity of the stimulation site within the finger as well as across fingers. The distribution of mislocalization across fingers deviates from a distribution expected by chance, showing a higher frequency of mislocalizations to the neighboring fingers than to more distant fingers. This observation in humans matches well with electrophysiological evidence from animal studies that some primary somatosensory cortex neurons have receptive fields that are not restricted to a single digit, but rather cover neighboring digits.

Reliable quantification of in vitro synthesized green fluorescent protein: comparison of fluorescence activity and total protein levels

At any time in vitro or in vivo expressed unlabeled proteins have to be quantified it is difficult to find a reliable method, especially with nonpurified samples. Quantification via protein activity can result in too low levels if the proteins analyzed tend to aggregate into inactive forms. Here, wild-type green fluorescent protein (GFPwt) was expressed in high amounts in vitro using the Rapid Translation System 500 based on Escherichia coli lysates. Fluorescent activity was determined in dependence of oxygen and compared to total protein levels. In the presence of low amounts of oxygen only 16% of the whole GFPwt amounts were detectable via determination of fluorescence activity. A reliable method to easily quantify whole protein levels even without specific antibodies and without purification steps by simple sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Coomassie blue staining is described.

Experience with growth hormone therapy in Turner syndrome in a single centre: low total height gain, no further gains after puberty onset and unchanged body proportions

The experience gained since 1987, through observation of 85 girls with Turner syndrome under growth hormone (GH) treatment, has enabled the analysis of one of the largest cohorts. Our results show that age, karyotype and height reflect the heterogeneity of the patients examined at our growth centre. In 47 girls, followed over 4 years on GH (median dose 0.72 IU/kg/week), the median age was 9.4 years and mean height SDS was -3.55 (Prader) and -0.14 (Turner-specific), while height and other anthropometrical parameters [weight, body mass index, sitting height (SH), leg length (LL) SH/LL, head circumference, arm span] were documented and compared to normative data as well as to Turner-specific references established on the basis of a larger (n = 165) untreated cohort from Tübingen. The latter data are also documented in this article. Although there was a trend towards normalization of these parameters during the observation period, no inherent alterations in the Turner-specific anthropometric pattern occurred. In 42 girls who started GH treatment at a median age of 11.8 years, final height (bone age >15 years) was achieved at 16.7 years. The overall gain in height SDS (Turner) from start to end of GH therapy was 0.7 (+/- 0.8) SD, but 0.9 (+/- 0.6) SD from GH start to onset of puberty (spontaneous 12.2 years, induced 13.9 years) and -0.2 (+/- 0.8) from onset of puberty to end of growth. Height gain did not occur in 12 patients (29%) and a gain of > 5 cm was only observed in 16 patients (38%). Height gain correlated positively with age at puberty onset, duration, and dose of GH, and negatively with height and bone age at the time GH treatment started. Final height correlated positively with height SDS at GH start and negatively with the ratio of SH/LL (SDS). We conclude that, in the future, GH should be given at higher doses, but oestrogen substitution should be done cautiously, owing to its potentially harmful effect on growth. LL appears to determine height variation in Turner syndrome and the potential to treat short stature successfully with GH.

Activity patterns of human somatosensory cortex adapt dynamically to stimulus properties

Long-term synchronous tactile stimulation of two sites of the body results in integrated, overlapping cortical representations whereas asynchronous stimulation leads to segregated representations. To investigate the cortical capacity to adapt dynamically to stimulation properties 22 subjects were stimulated at digits 1, 3 and 5 of both hands in either random or fixed order. Changes in the functional organization of the somatosensory cortex were inferred by neuromagnetic source analysis based on somatosensory evoked magnetic fields. Compared to the stimulation in random sequence, the stimulation in fixed order revealed a reduction in distance between the cortical representation of D1 and D3. We conclude that the pattern of activation in the somatosensory cortex adapts dynamically to the spatio-temporal characteristics of the stimuli.

Dosing of growth hormone in growth hormone deficiency

Growth hormone (GH) treatment of GH-deficient (GHD) children is to a certain extent standardized worldwide. Recombinant 22 kDa GH is injected once daily by the subcutaneous route, mostly in the evening. The amount of GH injected (calculated per kg body weight or body surface area, expressed in terms of IU or mg) in prepubertal children mimics the known production rate (approximately 0.02 mg [0. 06 IU]/kg body weight per day). However, there is a wide variation in dosage, the reasons for which are partly unknown and partly due to national traditions and regimes imposed by authorities regulating reimbursement. The situation during puberty is less standardized, with most clinicians still not increasing the dosage according to known production rates. The results of these approaches in terms of adult height outcome are not always satisfactory. In order to achieve optimal height development during childhood, puberty and adulthood, strategies must be developed to individualize GH dosing according to set therapeutical goals taking into account efficacy, safety and cost. The implementation of prediction algorithms will help us to reach these goals. In addition, other response variables will have to be monitored during treatment in order to correct for deficits resulting from GHD.

Differential activation in somatosensory cortex for different discrimination tasks

Maps of the body surface in somatosensory cortex have been shown to be highly plastic, altering their configuration in response to changes in use of body parts. The current study investigated alterations in the functional organization of the human somatosensory cortex resulting from massed practice. Over a period of 4 weeks, subjects were given synchronous tactile stimulation of thumb (D1) and little finger (D5) for 1 hr/d. They had to identify the orientation of the stimuli. Neuroelectric source localization based on high-resolution EEG revealed that, when subjects received passive tactile stimulation of D1 or D5, the representations of the fingers in primary somatosensory cortex were closer together after training than before. There was also an apparently correlative tendency to anomalously mislocalize near-threshold tactile stimuli equally to the distant finger costimulated during training rather than preferentially to the finger nearest to the finger stimulated in a post-training test. However, when the stimulus discrimination had to be made, neuroelectric source imaging revealed that the digital representations of D1 and D5 were further apart after training than before. Thus, the same series of prolonged repetitive stimulations produced two different opposite effects on the spatial relationship of the cortical representations of the digits, suggesting that differential activation in the same region of somatosensory cortex is specific to different tasks.

GB virus C prevalence in blood donors and high risk groups for parenterally transmitted agents from Gauteng, South Africa

The prevalence of GBV-C infection in voluntary blood donors and in groups at high risk for parenteral exposure to infectious agents was studied. The high risk groups included chronic renal failure patients on haemodialysis, renal transplant patients and haemophiliacs from Gauteng. The presence of GBV-C RNA in these populations was determined using reverse transcription polymerase chain reaction (RT-PCR) in the 5' non-coding region (NCR) of the virus. Of the blood donors, 11.1% (95% CI 7.6, 15.8) were positive, whereas 23.8% (95% CI 12.6, 40.2) of haemodialysis patients and 23.5% (95% CI 15.9, 33.3) of the haemophiliacs were infected with GBV-C. The highest proportion of infection was in the renal transplant patients, where 41.2% (95% CI 35.1, 47.7) were found to have circulating GBV-C RNA. Serological markers for hepatitis B (HBV) and hepatitis C viruses (HCV) were also measured as indicators of other hepatitis viruses with important parenteral transmission routes. Of the GBV-C positive blood donors, 3.6% were also HBsAg positive and none were positive for HCV. The GBV-C positive patients on haemodialysis were not positive for either HBsAg or antibodies to HCV, but had evidence of past infection with HBV since 40% were anti-HBc positive. The greatest proportion of HCV positives was in the haemophiliac group, 91.3%, none of these were HBsAg positive but 39.1% had anti-HBc. In the GBV-C positive renal transplant patients, 4% had HBsAg, 13.3% had anti-HBc and 2.1% had antibodies to HCV. This is the first report describing the prevalence of GBV-C in South African populations.

GB virus C prevalence in blood donors and high risk groups for parenterally transmitted agents from Gauteng, South Africa

The prevalence of GBV-C infection in voluntary blood donors and in groups at high risk for parenteral exposure to infectious agents was studied. The high risk groups included chronic renal failure patients on haemodialysis, renal transplant patients and haemophiliacs from Gauteng. The presence of GBV-C RNA in these populations was determined using reverse transcription polymerase chain reaction (RT-PCR) in the 5' non-coding region (NCR) of the virus. Of the blood donors, 11.1% (95% CI 7.6, 15.8) were positive, whereas 23.8% (95% CI 12.6, 40.2) of haemodialysis patients and 23.5% (95% CI 15.9, 33.3) of the haemophiliacs were infected with GBV-C. The highest proportion of infection was in the renal transplant patients, where 41.2% (95% CI 35.1, 47.7) were found to have circulating GBV-C RNA. Serological markers for hepatitis B (HBV) and hepatitis C viruses (HCV) were also measured as indicators of other hepatitis viruses with important parenteral transmission routes. Of the GBV-C positive blood donors, 3.6% were also HBsAg positive and none were positive for HCV. The GBV-C positive patients on haemodialysis were not positive for either HBsAg or antibodies to HCV, but had evidence of past infection with HBV since 40% were anti-HBc positive. The greatest proportion of HCV positives was in the haemophiliac group, 91.3%, none of these were HBsAg positive but 39.1% had anti-HBc. In the GBV-C positive renal transplant patients, 4% had HBsAg, 13.3% had anti-HBc and 2.1% had antibodies to HCV. This is the first report describing the prevalence of GBV-C in South African populations.

How can we share the portal blood inflow in auxiliary partial heterotopic liver transplantation without portal hypertension?

BACKGROUND

Auxiliary partial heterotopic liver transplantation (APHLT) may be an attractive treatment for fulminant hepatic failure in which recovery of the host liver is expected. We investigated the functional relationship between an auxiliary heterotopic partial liver graft and the host liver with or without portal hypertension in pigs.

METHODS

Sixteen pigs underwent hepatic artery ligation and APHLT; in addition, various degrees of portal hypertension were created by banding the host portal vein. The pigs were randomly divided into three groups: group A (n = 5), the host portal vein was not banded; group B (n = 6), the host portal vein was banded to make the host portal pressure higher than that of the graft by 2 mm Hg; and group C (n = 5), the host portal vein was banded to make the host portal pressure the same as that of the graft.

RESULTS

All of the pigs in group A had necrotic and atrophied grafts with graft portal vein thrombosis and well-hypertrophied host livers. All of the pigs in group B had well-functioning grafts and necrotic and atrophied host livers. Three of the five pigs in group C had well-functioning grafts and host livers, although the remaining two pigs exhibited the same results as those in group A.

CONCLUSIONS

APHLT could be a valuable alternative treatment for temporary support in fulminant hepatic failure. However, if the recipient does not exhibit portal hypertension, the host portal vein should be banded to make the host portal pressure at least the same as that of the graft.

Cigarette smoking, blood lipids, and baroreceptor-modulated nociception

Activation of arterial blood pressure has been shown to influence higher central nervous activity. In animals, induction of sleep-like states and increases of seizure and pain thresholds in response to baroreceptor stimulation have been reported. In certain human groups, mechanical stimulation of the carotid baroreceptors also increases pain thresholds. The present paper examines the hypothesis that smokers show baroreceptor dependent antinociception as compared to non-smokers. It is speculated that one effect which rewards smoking is the nicotine induced phasic blood pressure increase which leads to baroreceptor stimulation and dampens pain perception. One hundred and twenty subjects were investigated using a recently developed mechanical baroreceptor stimulation technique and an electrical pain stimulus. The group of heavy smokers showed the predicted effect: their pain thresholds were enhanced during conditions of increased baroreceptor activity as compared to the control condition. The group of medium, light and non-smokers, however, did not show this effect. Neither blood lipid levels nor diastolic or systolic blood pressure paralleled the group differences on baroreceptor dependent antinociception. In heavy smokers, the nicotine induced phasic blood pressure increases might have baroreceptor dependent pain dampening effects, which might be among the reinforcing qualities of smoking.