The effect of arabinoxylooligosaccharides on upper gastroduodenal motility and hunger ratings in humans

BACKGROUND AND AIMS

Prebiotics such as Arabinoxylooligosaccharides (AXOS) are non-digestible, fermentable food ingredients stimulating growth/activity of colonic bacteria with enhanced carbohydrates fermentation (CF) in humans. The migrating motor complex (MMC) of the gastrointestinal tract has been recently identified as an important hunger signal, but no data are available yet on the role of acute CF on MMC activity and related hunger ratings. Thus, we aimed to study the effect of acute AXOS CF on MMC and hunger in humans.

METHODS

A total of 13 healthy volunteers were randomized in a single-blind crossover placebo-controlled study where 9.4 g of AXOS or 10 g of maltodextrin and 1 g of unlabelled lactose ureide (LU) were given 12 hours prior to the study and, in the next morning, together with a pancake containing 500 mg of ¹³ C-LU. In 10 hours after the meal, ¹³ CO₂ and hydrogen excretion were determined every 15 minutes while hunger/appetite ratings every 2 minutes through a VAS questionnaire. Five hours after the meal, antroduodenal motility was measured using HRM.

KEY RESULTS

AXOS significantly increased CF (158 ± 81 vs 840 ± 464 H2 ppm*minute, placebo vs AXOS, P < .05) without affecting the orocecal transit time (OCTT). AXOS had no significant effect on the occurrence, origin, and duration of phase III and on the total number, origin, and duration of phases I and II. Hunger and appetite scores prior and after phase III were not affected by AXOS.

CONCLUSIONS

AXOS acutely increases colonic fermentation, but this neither affects OCTT, activity of the MMC, nor interdigestive hunger scores in man.

Clinical presentation and outcome of children with central diabetes insipidus associated with a self-limited or transient pituitary stalk thickening, diagnosed as infundibuloneurohypophysitis

OBJECTIVE

Despite lymphocytic or autoimmune infundibuloneurohypophysitis (INH) is an increasingly recognized aetiology in children with central diabetes insipidus (CDI); clinical data on epidemiology (clinical evolution, predisposing factors, complications), diagnosis and management of this entity are limited and mostly based on published case reports. The aim of this study was to gain a broader insight in the natural history of this disease by analysing the clinical presentation, radiological pituitary stalk changes, associated autoimmunity and hormonal deficiencies in children with CDI and a self-limiting or transient stalk thickening (ST), diagnosed as autoimmune infundibuloneurohypophysitis, during the last 15 years in four Belgian university hospitals.

DESIGN AND PATIENTS

The medical files of nine CDI patients with a ST at initial presentation and no signs of Langerhans cell histiocytosis or germinoma at presentation and/or during follow-up of more than 1.5 years were reviewed.

RESULTS

Age at presentation ranged from 3 to 14 years. Two patients had a positive family history of autoimmunity. Three children presented with associated growth failure, two with nausea and one with long-standing headache. Median maximal diameter of the stalk was 4.6 mm (2.7-10 mm). Four patients had extra-pituitary brain anomalies, such as cysts. One patient had central hypothyroidism, and another had a partial growth hormone deficiency at diagnosis. Within a mean follow-up of 5.4 (1.5-15) years, stalk thickening remained unchanged in two patients, regressed in one and normalized in six children. CDI remained in all, while additional pituitary hormone deficiencies developed in only one patient.

CONCLUSIONS

In this series of children INH with CDI as initial presentation, CDI was permanent and infrequently associated with anterior pituitary hormone deficiencies, despite a frequent association with nonstalk cerebral lesions.

Expanding the CHARGE Geno-Phenotype: A Girl with Novel CHD7 Deletion, Hypogonadotropic Hypogonadism, and Agenesis of Uterus and Ovaries

BACKGROUND

CHARGE syndrome is a variable entity. Clinical diagnosis is based on the Blake-Verloes criteria and can be confirmed by identifying a mutation or deletion in the CHD7 gene. Hypoplasia of the male genitalia and lack or incomplete secondary sexual development in both sexes is a common feature, and is most often attributable to hypogonadotropic hypogonadism which is described in >80% of the CHARGE patients. Other genital anomalies in CHARGE patients are rare.

METHODS AND RESULTS

We describe the case of a girl with a novel heterozygous deletion in exon 15 of the CHD7 gene and combined agenesis of uterus and ovaries, besides gonadotropin deficiency, thus expanding the geno-phenotype of CHARGE syndrome.

CONCLUSION

In case of persistent primary amenorrhea, despite estrogen replacement, this unusual combination should be considered in girls with CHARGE syndrome.

Short Stature in KBG Syndrome: First Responses to Growth Hormone Treatment

BACKGROUND

KBG syndrome is a rare disorder characterized by intellectual disability and associated with macrodontia of the upper central incisors, specific craniofacial findings, short stature and skeletal anomalies. Genetic corroboration of a clinical diagnosis has been possible since 2011, upon identification of heterozygous mutations in or a deletion of the ANKRD11 gene.

METHODS

We summarized the height data of 14 adults and 18 children (age range 2-16 years) with a genetically confirmed diagnosis of KBG syndrome. Two of these children were treated with growth hormones.

RESULTS

Stature below the 3rd centile or -1.88 standard deviation score (SDS) was observed in 72% of KBG children and in 57% of KBG adults. Height below -2.50 SDS was observed in 62% of KBG children and in 36% of KBG adults. The mean SDS of height in KBG children was -2.56 and in KBG adults -2.17. Two KBG children on growth hormone therapy increased their height by 0.6 and 1 SDS within 1 year, respectively. The former also received a gonadotropin-releasing hormone agonist due to medical necessity.

CONCLUSION

Short stature is prevalent in KBG syndrome, and spontaneous catch-up growth beyond childhood appears limited. Growth hormone intervention in short KBG children is perceived as promising.

Evaluation of the hypothalamic-pituitary-adrenal axis and its relationship with central respiratory dysfunction in children with Prader-Willi syndrome

BACKGROUND

Children with Prader-Willi Syndrome (PWS) have been considered at risk for central adrenal insufficiency (CAI). Hypothalamic dysregulation has been proposed as a common mechanism underlying both stress-induced CAI and central respiratory dysfunction during sleep.

OBJECTIVE

To evaluate CAI and sleep-related breathing disorders in PWS children.

PATIENTS AND METHODS

Retrospective study of cortisol response following either insulin tolerance test (ITT) or glucagon test (GT) in 20 PWS children, and comparison with 33 non- Growth Hormone deficient (GHD) controls. Correlation between sleep related breathing disorders and cortisol response in 11 PWS children who received both investigations.

RESULTS

In PWS children, the cortisol peak value showed a significant, inverse correlation with age (Kendall's τ = -0.411; p = 0.012). A similar though non-significant correlation was present between cortisol increase and age (τ = -0.232; p = 0.16). Similar correlations were found in controls. In only 1 of 20 PWS children (5 %), ITT was suggestive of CAI. Four patients had an elevated central apnea index but they all exhibited a normal cortisol response. No relationship was found between peak cortisol or cortisol increase and central apnea index (respectively p = 0.94 and p = 0.14) or the other studied polysomnography (PSG) parameters.

CONCLUSIONS

CAI assessed by ITT/GT is rare in PWS children. Our data do not support a link between CAI and central respiratory dysregulation.

Insulin sensitivity modulates the growth response during the first year of high-dose growth hormone treatment in short prepubertal children born small for gestational age

AIM

To study the relationship between insulin sensitivity and growth response in short children born small for gestational age (SGA) treated with growth hormone (GH).

METHODS

Randomized, open-label, 24-month intervention study in 40 short prepubertal SGA children [age (mean ± SD) 5.3 ± 1.5 years], who either remained untreated (n = 20) or were treated with GH (66 µg/kg/day; n = 20). Changes in fasting glucose, insulin, quantitative insulin sensitivity check index (QUICKI), IGF-1 and leptin after 1 and 2 years were studied.

RESULTS

Mean height SDS increased from -3.3 ± 0.7 to -2.3 ± 0.7 after 1 year, and to -1.9 ± 0.7 after 2 years of treatment. QUICKI decreased significantly (p = 0.008) in the first year of GH treatment and stabilized in the second year. Baseline QUICKI was positively associated (r = 0.40; p < 0.05) with the change in height SDS in the first year.

CONCLUSION

Higher insulin sensitivity at the start of GH therapy is associated with greater first-year growth response to GH, and could be a promising parameter in selecting prepubertal short SGA children for GH treatment. However, this finding needs to be confirmed in larger studies.

Detailed studies of growth hormone secretion in cystinosis patients

BACKGROUND

Cystinosis is an autosomal recessive disorder characterized by intralysosomal cystine accumulation. Growth retardation is more pronounced in cystinosis than in other chronic kidney diseases and is mostly not corrected by cysteamine.

METHODS

Growth was evaluated in nine cystinosis patients, all treated with cysteamine, both after cysteamine and recombinant human growth hormone (rhGH) therapy initiation. Growth hormone (GH) secretion was studied by nocturnal GH measurements in four of nine patients and by glucagon test in four of nine patients.

RESULTS

RhGH was administered to seven of nine patients. At rhGH initiation, height was below -2 SDS in five of seven patients, final height was above -2 SDS in six of seven. In two patients not treated with rhGH, final height remained below -4 SDS despite cysteamine treatment being started at the age of 6.1 and 8.1 years, respectively. Nocturnal GH secretion was normal in all patients. Glucagon tests revealed GH deficiency in one patient; two of four patients had abnormal GH peak timing.

CONCLUSIONS

We present the first reported case of GH deficiency in cystinosis. Although no overt GH deficiency was detected in other patients, abnormal GH peak timing can indicate a subclinical GH secretion problem. RhGH significantly improved growth in cystinosis patients and should be initiated early in life.

Two novel deletions in hypotonia-cystinuria syndrome

Hypotonia-cystinuria syndrome (HCS) is an autosomal recessive disorder caused by combined deletions of SLC3A1 and PREPL. Clinical features include cystinuria, neonatal hypotonia with spontaneous improvement, poor feeding in neonates, hyperphagia in childhood, growth hormone deficiency, and variable cognitive problems. Only 14 families with 6 different deletions have been reported. Patients are often initially misdiagnosed, while correct diagnosis enables therapeutic interventions. We report two novel deletions, further characterizing the clinical and molecular genetics spectrum of HCS.

Methylation defect in imprinted genes detected in patients with an Albright's hereditary osteodystrophy like phenotype and platelet Gs hypofunction

BACKGROUND

Pseudohypoparathyroidism (PHP) indicates a group of heterogeneous disorders whose common feature is represented by impaired signaling of hormones that activate Gsalpha, encoded by the imprinted GNAS gene. PHP-Ib patients have isolated Parathormone (PTH) resistance and GNAS epigenetic defects while PHP-Ia cases present with hormone resistance and characteristic features jointly termed as Albright's Hereditary Osteodystrophy (AHO) due to maternally inherited GNAS mutations or similar epigenetic defects as found for PHP-Ib. Pseudopseudohypoparathyroidism (PPHP) patients with an AHO phenotype and no hormone resistance and progressive osseous heteroplasia (POH) cases have inactivating paternally inherited GNAS mutations.

METHODOLOGY/PRINCIPAL FINDINGS

We here describe 17 subjects with an AHO-like phenotype that could be compatible with having PPHP but none of them carried Gsalpha mutations. Functional platelet studies however showed an obvious Gs hypofunction in the 13 patients that were available for testing. Methylation for the three differentially methylated GNAS regions was quantified via the Sequenom EpiTYPER. Patients showed significant hypermethylation of the XL amplicon compared to controls (36 ± 3 vs. 29 ± 3%; p<0.001); a pattern that is reversed to XL hypomethylation found in PHPIb. Interestingly, XL hypermethylation was associated with reduced XLalphaS protein levels in the patients' platelets. Methylation for NESP and ExonA/B was significantly different for some but not all patients, though most patients have site-specific CpG methylation abnormalities in these amplicons. Since some AHO features are present in other imprinting disorders, the methylation of IGF2, H19, SNURF and GRB10 was quantified. Surprisingly, significant IGF2 hypermethylation (20 ± 10 vs. 14 ± 7%; p<0.05) and SNURF hypomethylation (23 ± 6 vs. 32 6%; p<0.001) was found in patients vs. controls, while H19 and GRB10 methylation was normal.

CONCLUSION/SIGNIFICANCE

In conclusion, this is the first report of methylation defects including GNAS in patients with an AHO-like phenotype without endocrinological abnormalities. Additional studies are still needed to correlate the methylation defect with the clinical phenotype.

Adult final height after GH therapy for irradiation-induced GH deficiency in childhood survivors of brain tumors: the Belgian experience

OBJECTIVES

The treatment of brain tumors in childhood is frequently complicated by growth retardation with a high proportion of irradiation (Irr)-induced GH deficiency (GHD) resulting in reduced adult final height (AFH) even after GH therapy (GHT). In order to optimize future GHT protocols, more information on the factors influencing the growth response to GH in these children is needed. This retrospective study evaluated AFH and influencing auxological and treatment factors of a standardized daily biosynthetic GHT in childhood survivors of brain tumors with documented GHD after brain Irr.

DESIGN AND METHODS

From the Belgian GH Registry, 57 children survivors of a brain tumor outside the hypothalamo-pituitary area with available AFH were stratified into two groups depending on cranial (C-Irr; n=25) or craniospinal (CS-Irr; n=32) Irr.

RESULTS

In the C-Irr patients, results showed an AFH of -0.8 (-2.5, 1.4) SDS (median (range)) and in the CS-Irr patients, results showed a significantly (P<0.001) lower AFH of -1.8 (-4.2, 0.0) SDS. AFH SDS corrected for mid-parental height (MPH) in the C-Irr group was -0.5 (-2.2, 0.9) and -1.5 (-3.6, 0.0) SDS in the CS-Irr group. AFH was positively correlated with age at end of tumor therapy, height SDS at start GHT, height gain SDS first year GHT, and negatively correlated with CS-Irr.

CONCLUSIONS

GHT failed to restore adult height to MPH in nearly half of Irr-induced GHD patients for brain tumor, especially those receiving CS-Irr, irradiated at a younger age or shorter at start GHT.

Tumor spectrum in children with Noonan syndrome and SOS1 or RAF1 mutations

Noonan syndrome (NS) is an autosomal dominant disorder caused by mutations in PTPN11, KRAS, SOS1, and RAF1. We performed SOS1, RAF1, BRAF, MEK1, and MEK2 mutation analysis in a cohort of 102 PTPN11- and KRAS-negative NS patients and found pathogenic SOS1 mutations in 10, RAF1 mutations in 4, and BRAF mutations in 2 patients. Three novel SOS1 mutations were found. One was classified as a rare benign variant and the other remains unclassified. We confirm a high prevalence of pulmonic stenosis and ectodermal abnormalities in SOS1-positive patients. Three patients with SOS1 mutations presented with tumors (embryonal rhabdomyosarcoma, Sertoli cell testis tumor, and granular cell tumors of the skin). One patient with a RAF1 mutation had a lesion suggestive for a giant cell tumor. This is the first report describing different tumor types in NS patients with germ line SOS1 mutations.

Has the prevalence of congenital abnormalities after intracytoplasmic sperm injection increased? The Leuven data 1994-2000 and a review of the literature

BACKGROUND

Although intracytoplasmic sperm injection (ICSI) is now accepted as the treatment of choice for severe male infertility, concerns about its safety and the potential risks for the offspring remain. We reviewed the literature with respect to the prevalence of major congenital malformations after the ICSI technique and supplemented these data with the results of a prospective follow-up study performed in our center.

METHODS

From January 1994 till June 2000, 776 ICSI cycles were carried out at the Leuven University Fertility Center. The resulting pregnancies (n = 172) were followed for biochemical and obstetrical parameters, prenatal diagnosis and congenital abnormalities.

RESULTS

A total of 134/172 (78%) ongoing pregnancies resulted in 132 deliveries of 166 live born children. Two terminations of pregnancy were carried out due to the presence of major congenital anomalies, diagnosed at prenatal ultrasound. Prenatal diagnosis was carried out in 55 fetuses. Two de novo chromosomal aberrations were found. Major congenital abnormalities were observed at birth in 9/150 (6.0%) children. The total malformation rate was 6.5%.

CONCLUSIONS

The prevalence of congenital abnormalities in children born after ICSI in our center (6.5%) was comparable to the prevalence of congenital abnormalities after ICSI reported in the literature.

Long-term GH treatment improves adult height in children with Noonan syndrome with and without mutations in protein tyrosine phosphatase, non-receptor-type 11

CONTEXT

Noonan syndrome (NS) is characterized by short stature, typical facial dysmorphology and congenital heart defects. Short-term effect of GH therapy in NS is beneficial, reports on the effect on adult height are scarce.

OBJECTIVE

To determine the effect of long-term GH therapy in children with NS.

DESIGN

Twenty-nine children with NS were treated with GH until final height was reached.

SETTING

Hospital endocrinology departments.

PATIENTS

Children with the clinical diagnosis of NS, with mean age at the start of therapy of 11.0 years, 22 out of 27 tested children had a mutation in the protein tyrosine phosphatase, non-receptor-type 11 gene (PTPN11 gene). Interventions GH was administered subcutaneously at 0.05 mg/kg per day until growth velocity was 1 cm/6 months.

MAIN OUTCOME MEASURE

Linear growth (height) was measured at 3-month intervals in the first year and at 6-month intervals thereafter until final height.

RESULTS

At the start of treatment, median height SDS (H-SDS) was -2.8 (-4.1 to -1.8) and 0.0 (-1.4 to +1.2), based on national and Noonan standards respectively. GH therapy lasted for 3.0-10.3 years (median, 6.4), producing mean gains in H-SDS of +1.3 (+0.2 to +2.7) and +1.3 (-0.6 to +2.4), based on national and Noonan standards respectively. In 22 children with a mutation in PTPN11 mean gain in H-SDS for National standards was +1.3, not different from the mean gain in the five children without a mutation in PTPN11+1.3 (P=0.98).

CONCLUSION

Long-term GH treatment in NS leads to attainment of adult height within the normal range in most patients.

Effect of 2 years of high-dose growth hormone therapy on cognitive and psychosocial development in short children born small for gestational age

OBJECTIVE AND DESIGN

Children born small for gestational age (SGA) are not only at risk for short stature, but also for neurodevelopmental and behavioral problems. In this study, we analyzed the effects of high-dose GH therapy on cognitive development and psychosocial functioning in 34 prepubertal (3-8 years) short SGA children, equally randomized into a GH-treated group (TRG) and an untreated group (UTRG).

METHODS

At start and after 2 years, children underwent standardized tests measuring the intellectual abilities (Wechsler Preschool and Primary Scale of Intelligence-Revised, or Wechsler Intelligence Scale for Children-Revised); their parents completed a standardized questionnaire evaluating psychosocial functioning (Child Behavior Checklist; CBCL).

RESULTS

At start, total IQ scores were significantly (P < 0.05) lower in the SGA group than in the general population: 32% of the SGA patients had scores below 85. After 2 years, IQ scores remained unchanged in the TRG, but increased significantly (P < 0.05) in the UTRG. After exclusion of children with developmental problems, however, no significant changes in IQ scores occurred in the UTRG as well as the TRG. At baseline, 24% (8/34) children had problematic CBCL total problems scores, equally distributed among the two groups; no significant changes in the different subscale scores occurred after 2 years.

CONCLUSION

No beneficial effect of 2 years of GH therapy on cognitive and behavioral profile could be observed in a cohort of rather young short SGA children presenting a variable degree of developmental delay and behavioral problems. Subsequent follow-up could reveal potential long-term effects of GH therapy on development and behavior.

Concerning mistreatment of older people: Clinical and ethical thoughts based on a study of known cases

Following a report by the Health Ministry recommending a greater implication of general practitioners (GP) in the diagnosis and care of mistreated older people, we wanted to evaluate what was actually their role in this matter. A study was made of files of mistreated older persons referred to the social services in a Parisian suburb. For each file, we noted who raised the first suspicions of mistreatment, who diagnosed it, what happened next, and what precisely the GP's role was. Out of 600 files, we found 12 cases, concerning 14 persons (two couples). Although all the patients had health problems requiring frequent consultations with their GP, none of these situations were diagnosed by the GP. In all cases, the GP played only a secondary role, if at all. The following points are discussed: The link between family problems and history cannot be ignored in the follow up of such situations. The GP's role is discussed regarding clinical knowledge of mistreatment and the legal rules they have to deal with. Our results bring to light how the balance between the person's autonomy and the necessary direct action is especially delicate in this field.

Deletion of PREPL, a gene encoding a putative serine oligopeptidase, in patients with hypotonia-cystinuria syndrome

In 11 patients with a recessive congenital disorder, which we refer to as "the hypotonia-cystinuria syndrome," microdeletion of part of the SLC3A1 and PREPL genes on chromosome 2p21 was found. Patients present with generalized hypotonia at birth, nephrolithiasis, growth hormone deficiency, minor facial dysmorphism, and failure to thrive, followed by hyperphagia and rapid weight gain in late childhood. Since loss-of-function mutations in SLC3A1 are known to cause isolated cystinuria type I, and since the expression of the flanking genes, C2orf34 and PPM1B, was normal, the extended phenotype can be attributed to the deletion of PREPL. PREPL is localized in the cytosol and shows homology with prolyl endopeptidase and oligopeptidase B. Substitution of the predicted catalytic residues (Ser470, Asp556, and His601) by alanines resulted in loss of reactivity with a serine hydrolase-specific probe. In sharp contrast to prolyl oligopeptidase and oligopeptidase B, which require both aminoterminal and carboxyterminal sequences for activity, PREPL activity appears to depend only on the carboxyterminal domain. Taken together, these results suggest that PREPL is a novel oligopeptidase, with unique structural and functional characteristics, involved in hypotonia-cystinuria syndrome.

Androgens and fetal growth

Boys are heavier than girls at term birth. Children with a 46,XY karyotype and androgen insensitivity syndrome (clinically complete form and/or proven mutations in the androgen receptor gene) were found to have a birth weight comparable to that of girls. These findings support the hypothesis that the difference in birth weight between boys and girls is generated by androgen action.

Male pseudohermaphroditism related to complications at conception, in early pregnancy or in prenatal growth

We examined whether male pseudohermaphroditism, when unexplained, is associated with reduced prenatal growth. Birth weight SD scores of 29 children with male pseudohermaphroditism were compared. The scores of children with an unexplained condition (median -2.1 SD) were found to be lower (p = 0.0001) than those of children with an explained condition (median -0.4 SD). In the majority of cases of unexplained male pseudohermaphroditism, there was a complicated history before conception or in early pregnancy. In conclusion, hitherto unexplained male pseudohermaphroditism was found to be associated with reduced prenatal growth and complications at conception or in early pregnancy.

Precocious pubarche, hyperinsulinism, and ovarian hyperandrogenism in girls: relation to reduced fetal growth

Pronounced adrenarche with precocious pubarche (PP) in girls has been associated with hyperinsulinism and subsequent functional ovarian hyperandrogenism (FOH). Recently, pronounced adrenarche and insulin resistance have each been related to low birth weight. We have now tested the hypothesis that the frequent concurrence of PP with pronounced adrenarche, FOH, and hyperinsulinemia in girls may be secondary to separate relationships between these conditions and low birth weight. A total of 185 girls (aged 5-18 yr) without endocrinopathy or with PP and pronounced adrenarche with or without FOH were studied; mean serum insulin (MSI) concentrations were determined after a standardized oral glucose tolerance test. Birth weight SD scores [mean (SEM)] of control girls (0.38+/-0.08; n = 83) were higher (P < 0.0001) than those of PP girls (-0.81+/-0.13; n = 102). Among postmenarcheal PP girls, birth weight SD scores of girls without FOH (-0.25+/-0.19; n = 25) were higher (P < 0.0001) than those in girls with FOH (-1.51+/-0.28; n = 23). In pubertal girls (n = 145), MSI levels correlated negatively with birth weight SD scores (r = -0.48; P < 0.05), independently of PP. MSI levels in girls with birth weight below 1 SD (93+/-9 mU/L; n = 33) were higher (P < 0.0001) than those in girls with birth weight between -1 and +1 SD (52+/-2 mU/L; n = 94), whereas glycemia profiles were comparable. Integration of the aforementioned data suggests that there may be a sequence in the associations between reduced fetal growth and components of the postnatal endocrine system; minor fetal growth reduction appears to be associated with amplified adrenarche, whereas more pronounced prenatal growth restriction seem to precede FOH and hyperinsulinemia during adolescence. In conclusion, these findings corroborate the hypothesis that the frequent concurrence of PP (with pronounced adrenarche), FOH, and hyperinsulinemia in girls may result from a common early origin (low birth weight serving as a marker), rather than from a direct interrelationship later in life.

Growth hormone treatment of short children born small for gestational age

Short children born small-for-gestational-age (SGA) appear to be at an increased risk of having a poly-endocrinopathy, including a degree of growth hormone (GH) deficiency and/or insulin-like growth factor 1 (IGF-1) resistance. Among GH-deficient children, those born SGA present a lower growth response to GH therapy than those not born SGA. The growth response of short SGA children to GH treatment does not appear to depend significantly on the secretory status of GH (as judged by provocative testing), indicating that the SGA condition (IGF-1 resistance) predominates over the availability of endogenous GH in determining the short stature of the majority of these children. When a higher than replacement dose of GH is administered, the growth response of short SGA children matches that of GH-deficient non-SGA children, indicating that the IGF-1 resistance towards growth can be overcome, and that a normal stature can be obtained, at least throughout childhood. It is anticipated that, increasingly, the indications and the doses for GH therapy in children will become interlinked with the emerging principles of endocrine programming in early life.

A novel TR beta mutation (R383H) in resistance to thyroid hormone syndrome predominantly impairs corepressor release and negative transcriptional regulation

Resistance to thyroid hormone (RTH) is characterized by elevated serum thyroid hormones, failure to suppress pituitary TSH secretion, and variable T3 responsiveness in peripheral tissues. The disorder is associated with diverse mutations that cluster within three areas of the thyroid hormone beta(TR beta) receptor. Here, we report a novel RTH mutation (R383H), which is located in a region not known to harbor naturally occurring mutations. Although the R383H mutant receptor activated positively regulated genes to an extent comparable to wild-type (WT), negative transcriptional regulation of human TSH alpha and TRH promoters was impaired in either TR beta 1 or TR beta 2 contexts, and WT receptor function was dominantly inhibited. T3-dependent changes in basal transcription with R383H were also impaired: on the TRH promoter, basal activation by unliganded R383H was not reversed by T3 to the same extent as WT; similarly transcriptional silencing by an unliganded Gal4-R383H fusion was not relieved at a T3 concentration that derepressed WT. In keeping with this, ligand-dependent corepressor release by R383H, either in a protein-protein interaction assay or as a DNA-bound heterodimer with retinoid X receptor on either positive or negative thyroid hormone response elements, was disproportionately impaired relative to its ligand-binding affinity, whereas its T3-dependent recruitment of coactivator was unimpaired. These properties were shared by another previously described RTH mutant (R429Q), and in the crystal structure of TR alpha the homologous residues interact in a polar invagination. Our data indicate a role for these residues in mediating negative transcriptional regulation and facilitating corepressor release and suggest that predominant impairment of these functions may be the minimal requirements for causation of RTH.

Low birth weight and subsequent male subfertility

Male subfertility often remains unexplained. Severe intrauterine growth retardation has previously been linked to hypergonadotropic hypogonadism. We examined whether reduced fetal growth, as judged by low birth weight, is associated with unexplained male subfertility later in life. Birth weight and gestational age were obtained by questionnaire from male partners of couples consulting for subfertility, and were transformed into birth weight SD scores. Men with normal semen analysis (n = 128) had a median birth weight SD score of 0.0 (P25-P75 range: -0.7 to 1.0), comparable to that of men with explained subfertility (n = 28), and higher (p = 0.012) than that of men with unexplained subfertility (n = 32; median -0.5 SD score; P25-P75 range: -0.9 to -0.1). These results extend the link between reduced fetal growth and male subfertility to a range of birth weight that is well within normality. The pathophysiologic mechanism governing this association now remains to be unraveled.

Adrenarche and fetal growth

Dehydroepiandrosterone sulfate (DHEAS) is prenatally secreted by the fetal adrenal, is an indicator of adrenarche from late childhood onward and is a marker of the individual hormonal milieu in the adult. The regulation of DHEAS secretion is still poorly understood. We postulated that serum DHEAS concentrations in children may be related to fetal growth. To test this hypothesis, serum DHEAS was measured at a median age of 8.2 y (range 5.8-16.0 y) in 13 pairs of discordant siblings after twin (n = 8), triplet (n = 4), or quadruplet (n = 1) pregnancy. At birth, one of each pair was small for gestational age (SGA) and the other had an appropriate weight (AGA), weight of the smallest infant was a median 67% (range 33-80%) of that of the largest sibling. In all 10 pairs with similar weight (< or = 1 SD difference) at the time of sampling, serum DHEAS concentration in the SGA child was higher (median 2-fold increase; range 1.1-7; p = 0.002) than in the AGA sibling. Conversely, in the 3 pairs with still discordant weight (> 2 SD difference), serum DHEAS levels in SGA children were lower than in AGA children. In conclusion, the presented findings, which account for both prenatal and postnatal weight gain, unmask a link between adrenarche and fetal growth. This relationship further supports the concept of early endocrine "programming" and extends this principle to adrenarche.

Empty sella, growth hormone deficiency and pseudotumour cerebri: effect of initiation, withdrawal and resumption of growth hormone therapy

An 11-year-old boy with normal visus and eye fundus, but with empty sella, growth hormone (GH) deficiency and central diabetes insipidus was found to have intracranial hypertension with papilloedema after 6 months of catch-up growth under recombinant human GH (rhGH) replacement therapy. Withdrawal of rhGH therapy was associated with normalisation of intracranial pressure within 1 week. Three months later, resumption of rhGH therapy at a lower dose was again followed by pronounced growth acceleration, but now without papilloedema.

CONCLUSION

Children with empty sella and GH deficiency may be prone to rhGH-induced pseudotumour cerebri which appears to be rapidly reversible and dose-dependent.

6-(substituted methylene)penems, potent broad spectrum inhibitors of bacterial beta-lactamase. IV. Kidney stability, serum binding and additional biological evaluation of racemic derivatives

Sodium (5RS)-Z-6-(substituted methylene)penem-3-carboxylates (3) are extremely potent inhibitors of bacterial beta-lactamases, but some members of this group of compounds are highly bound to human serum, while others are readily degraded by renal dehydropeptidase I enzyme. Consequently, the stability of a variety of 6-(substituted methylene)penems (3) to human kidney homogenate, their binding to human serum and their activity in a mouse infection model was investigated at an early stage, and were instrumental in the selection of the 1,2,3-triazolylmethylene derivatives (e.g. 3k) as a class of compounds worthy of further evaluation.