Rationale and design of a pilot study to evaluate the acceptability and effectiveness of a revised protein sparing modified fast (rPSMF) for severe obesity in a pediatric tertiary care weight management clinic.

Aggressive dietary interventions may provide an accessible treatment option for children and adolescents with severe obesity who are not successful with traditional lifestyle behavioral interventions or do not want or qualify for weight loss surgery. One such intensive dietary option is the protein sparing modified fast (PSMF). The PSMF involves minimal carbohydrate intake to induce ketosis, while maintaining adequate or high protein intake to minimize catabolism. The PSMF, under medical supervision, can be an effective and safe intervention for children and adolescents, yet the PSMF diet is not regularly used in the treatment of pediatric severe obesity. This paper describes the rationale and design for a pilot study to evaluate the acceptability and effectiveness of a revised PSMF (rPSMF) implemented as a weight loss treatment option for children and adolescents with severe obesity in a pediatric tertiary care weight management clinic. The primary aim of the study is to evaluate the acceptability of the rPSMF as assessed by adherence, satisfaction with the intervention, and participation rate using quantitative and qualitative methods. The secondary aim is to investigate the effectiveness of the rPSMF on improving a) anthropometric measures (weight, body mass index [BMI], BMI z-score); b) metabolic measures (lipid profile, glycosylated hemoglobin, liver function tests); and c) quality of life. Results of this study will provide guidance for the standardization of a pediatric rPSMF protocol in a clinic setting, delineate which factors improve or hinder adherence and weight loss and provide preliminary data for a multicenter randomized controlled trial. CLINICALTRIALSGOV IDENTIFIER: NCT03899311.

New predictive approaches for ITI treatment.

Immune tolerance induction (ITI) therapy in patients with haemophilia A and inhibitors constitutes a huge burden for affected patients and families and poses a large economic burden for a chronic disease. Concerted research efforts are attempting to optimize the therapeutic approach to the prevention and eradication of inhibitors. The Italian ITI Registry has provided data on 110 patients who completed ITI therapy as at July 2013. Analysis of independent predictors of success showed that, together with previously recognized factors - namely inhibitor titre prior to ITI, historical peak titre and peak titre on ITI - the type of causative FVIII gene mutation also contributes to the identification of patients with good prognosis and may be useful to optimize candidate selection and treatment regimens. Numerous studies have demonstrated that inhibitor reactivity against different FVIII products varies and is lower against concentrates containing von Willebrand factor (VWF). An Italian study compared inhibitor titres against a panel of FVIII concentrates in vitro and correlated titres with the capacity to inhibit maximum thrombin generation as measured by the thrombin generation assay (TGA). Observations led to the design of the PredictTGA study which aims to correlate TGA results with epitope specificity, inhibitor reactivity against different FVIII concentrates and clinical data in inhibitor patients receiving FVIII in the context of ITI or as prophylactic/on demand treatment. At the immunological level, it is known that T cells drive inhibitor development and that B cells secrete FVIII-specific antibodies. As understanding increases about the immunological response in ITI, it is becoming apparent that modulation of T-cell- and B-cell-mediated responses offers a range of potential new and specific approaches to prevent and eliminate inhibitors as well as individualize ITI therapy.

Effect of resistance training on body composition, self-efficacy, depression, and activity in postpartum women.

This study assessed the effect of resistance training (RT) in 60 healthy postpartum women. Participants were randomized to 18 weeks of RT or an active comparison group (flexibility training). RT and flexibility training (FT) exercises were completed twice-weekly based on the American College of Sports Medicine recommendations. Study outcomes included muscular strength, body composition (dual-energy x-ray absorptiometry), exercise self-efficacy, depressive symptoms [Center for Epidemiological Studies Depression Scale (CES-D)], and physical activity (accelerometery). For completers (n = 44), the RT group showed greater strength gains than the FT group, respectively (bench press: +36% vs +8%, P < 0.001; leg press: +31% vs +7%, P < 0.01; abdominal curl-ups: +228% vs +43%, P < 0.01); however, body composition changes were not different. There was a significant group × time interaction for exercise self-efficacy (F = 5.33, P = 0.026). For CES-D score, the RT group decreased (F = 4.61, P = 0.016), while the FT group did not; however, the group × time interaction in CES-D score was not significant (F = 1.33, P = 0.255). Sedentary time decreased (F = 5.27, P = 0.027) and light-intensity activity time increased (F = 5.55, P = 0.023) more in the RT than FT group. Intent-to-treat analyses did not alter the results. Twice-weekly RT increases strength and may be associated with better exercise self-efficacy and improved physical activity outcomes compared with FT in postpartum women.

Dangerous liaisons: how the immune system deals with factor VIII.

Only a fraction of patients with hemophilia A develop a neutralizing antibody (inhibitor) response to therapeutic infusions of factor VIII. Our present understanding of the underlying causes of the immunogenicity of this protein is limited. In the past few years, insights into the uptake and processing of FVIII by antigen-presenting cells (APCs) have expanded significantly. Although the mechanism of endocytosis remains unclear, current data indicate that FVIII enters APCs via its C1 domain. Its subsequent processing within endolysosomes allows for presentation of a heterogeneous collection of FVIII-derived peptides on major histocompatibility complex (MHC) class II, and this peptide-MHC class II complex may then be recognized by cognate effector CD4(+) T cells, leading to anti-FVIII antibody production. Here we aim to summarize recent knowledge gained about FVIII processing and presentation by APCs, as well as the diversity of the FVIII-specific T-cell repertoire in mice and humans. Moreover, we discuss possible factors that can drive FVIII immunogenicity. We believe that increasing understanding of the immune recognition of FVIII and the cellular mechanisms of anti-FVIII antibody production will lead to novel therapeutic approaches to prevent inhibitor formation in patients with hemophilia A.

Ensuring successful admission to hospital for young people with learning difficulties, autism and challenging behaviour: a continuous quality improvement and change management programme.

BACKGROUND: Children and young people with autism spectrum conditions frequently have adverse experiences in accessing health care. METHODS: An audit of experiences of families known to our tertiary service and hospital staff was conducted. A checklist asking about particular aspects of behaviour and communication was developed and incorporated into pre-admission planning. RESULTS: Awareness of the child/young person's communication needs and behaviours, plus good preplanning by all staff involved and a team member allocated to ensure that the care plan is carried through, has resulted in a vastly improved 'patient experience' from the perspective of family and staff. CONCLUSION: Children and young people with autism spectrum disorder, often with co-existing learning difficulties, vary greatly in their reactions to hospital admission. Preplanning that involves the family with a dedicated informed staff member can dramatically reduce distress and improve the patient and staff experience.

Haemophilia management: time to get personal?

The possibility of alloimmunization in patients receiving protein replacement therapy depends on (at least) three risk factors, which are necessary concomitantly but insufficient alone. The first is the degree of structural difference between the therapeutic protein and the patient's own endogenous protein, if expressed. Such differences depend on the nature of the disease mutation and the pre-mutation endogenous protein structure as well as on post-translational changes and sequence-engineered alterations in the therapeutic protein. Genetic variations in the recipients' immune systems comprise the second set of risk determinants for deleterious immune responses. For example, the limited repertoire of MHC class II isomers encoded by a given person's collection of HLA genes may or may not be able to present a 'foreign' peptide(s) produced from the therapeutic protein - following its internalization and proteolytic processing - on the surface of their antigen-presenting cells (APCs). The third (and least characterized) variable is the presence or absence of immunologic 'danger signals' during the display of foreign-peptide/MHC-complexes on APCs. A choice between existing therapeutic products or the manufacture of new proteins, which may be less immunogenic in some patients or patient populations, may require prior definition of the first two of these variables. This leads then to the possibility of developing personalized therapies for disorders due to genetic deficiencies in endogenous proteins, such as haemophilia A and B. [Correction made after online publication 11 July 2011: several critical corrections have been made to the abstract].

T-cell responses in two unrelated hemophilia A inhibitor subjects include an epitope at the factor VIII R593C missense site.

BACKGROUND: Development of neutralizing anti-factor (F)VIII antibodies ('inhibitors') is a serious clinical problem in hemophilia A. Increased inhibitor risk has been associated with certain FVIII missense substitutions, including R593C in the A2 domain. OBJECTIVES: The aim of the present study was to identify T-cell epitopes in FVIII and characterize T-cell responses in two unrelated hemophilia A subjects sharing F8-R593C and HLA-DRB1*1101 genotypes. We hypothesized that the hemophilic substitution site coincides with an important T-cell epitope. PATIENTS/METHODS: The binding affinities of peptides for recombinant HLA-DR proteins were measured and compared with epitope prediction results. CD4+ T cells were stimulated using peptides and stained with fluorescent, peptide-loaded tetramers. RESULTS: The inhibitor subjects, but not HLA-matched controls, had high-avidity HLA-DRB1*1101-restricted T-cell responses against FVIII(589-608), which contains the hemophilic missense site. Antigen-specific T cells secreted Th1 and Th2 cytokines and proliferated in response to FVIII and FVIII(592-603). FVIII(589-608) bound with physiologically relevant (micromolar) IC(50) values to recombinant DR0101, DR1101 and DR1501 proteins. CONCLUSIONS: Hemophilia A patients with R593C missense substitutions and these HLA haplotypes had an increased incidence of inhibitors in our cohorts, supporting a paradigm in which presentation of FVIII epitopes containing the wild-type R593 influences inhibitor risk in this hemophilia A sub-population.

HLA-DR-restricted T-cell responses to factor VIII epitopes in a mild haemophilia A family with missense substitution A2201P.

An HLA-DRA-DRB1*0101-restricted T-cell epitope in the factor VIII (FVIII) C2 domain occurred in a mild haemophilia A patient with missense substitution FVIII-A2201P. His T cells responded to synthetic peptides FVIII(2186-2205) and FVIII(2194-2213) (J Thromb Haemost 2007; 5: 2399). T cells from family members with genotype FVIII-A2201P were analysed to determine if FVIII-specific T cells occur in individuals with a haemophilic mutation but no clinically significant inhibitor response. Fluorescent MHC class II tetramers corresponding to subjects'HLA-DRB1 types were loaded with 20-mer peptides and utilized to label antigen-specific CD4+ T cells. T-cell responses to peptides spanning the FVIII-C2 sequence were evaluated. T cells recognizing specific peptides were cloned, and antigen specificity was verified by proliferation assays. Plasma and/or purified IgG samples were tested for FVIII inhibitory activity. CD4+ T cells and T-cell clones from two brothers who shared the DRB1*0101 allele responded to FVIII(2194-2213). A haemophilic cousin's HLA-DRA-DRB1*1104-restricted response to FVIII(2202-2221) was detected only when CD4+CD25+ cells were depleted. A great uncle and two obligate carriers had no detectable FVIII-C2-specific T cells. Concentrated IgG from the brother without a clinical inhibitor response showed a low-titre FVIII inhibitor. FVIII-specific T cells and inhibitory IgG were found in a previously infused, haemophilic subject who had a sub-clinical FVIII inhibitor. CD4+CD25+ depleted T cells from a non-infused haemophilic cousin recognized an overlapping FVIII epitope, indicating a latent HLA-DRA-DRB1*1104-restricted T-cell response to FVIII. Specific T-cell responses to FVIII can occur without clinically significant inhibitors.

Factor VIII mutations in 42 Moldovan haemophilia A families, including 12 that are novel.

Haemophilia A (HA) is a bleeding disorder caused by mutations within the X-linked F8 gene. A series of 42 unrelated Moldovan patients with HA had their disease-causative mutation determined to provide clinically valuable genotyping information for a historically underserved population and to utilize factor VIII (FVIII) structural information to analyse the effects of haemophilic missense substitutions. DNA samples were analysed to detect intron 22 and intron 1 inversions followed by heteroduplex analysis of PCR-amplified fragments containing all exonic sequences. Missense sites identified by DNA sequencing were visualized in the recently described crystal structures of human FVIII. Of the 26 different point mutations, 12 were novel. Gel electrophoresis identified samples with a second major DNA band that migrated abnormally; these amplified products were sequenced. Thirteen intron 22 inversions and one intron 1 inversion were found. Two patients had large, partial gene deletions and there were six frameshift, two non-sense, two splicing and 16 missense genotypes. Two subjects with an intron 22 inversion and one with a large, partial gene deletion developed an alloimmune inhibitor. Their localization suggests intra- and possibly inter-molecular interactions that are important for the structural integrity and/or procoagulant function of FVIII.

Relaxation and Simplex mathematical algorithms applied to the study of steady-state electrochemical responses of immobilized enzyme biosensors: Comparison with experiments.

A description of the implementation of the relaxation method with automatic mesh point allocation for immobilized enzyme electrodes is presented. The advantages of this method for the solution of coupled reaction-diffusion problems are discussed. The relaxation numerical simulation technique is combined with the Simplex fitting algorithm to extract kinetic parameters from experimental data. The results of the simulations are compared to experimental data from self-assembled multilayered electrodes comprised of glucose oxidase (GOx) and an Os modified redox mediator and found to be in excellent agreement.

T-cell responses over time in a mild hemophilia A inhibitor subject: epitope identification and transient immunogenicity of the corresponding self-peptide.

BACKGROUND: Antibodies that neutralize factor (F) VIII activity, clinically referred to as 'inhibitors', complicate the treatment of hemophilia A patients; current tolerance and bypass strategies are extremely costly and sometimes ineffective. The development of inhibitors requires T-cell help. OBJECTIVES: We characterized T-cell responses of a subject with mild hemophilia A with missense genotype A2201P for one year following his initial inhibitor response, with the goals of defining the primary epitope(s) and its (their) MHC Class II restriction. We investigated the possible involvement of regulatory T cells in modulating immune responses. PATIENTS/METHODS: The subject developed high-titer FVIII-neutralizing antibodies (250 BU mL(-1)) that declined over time to 8 BU ml(-1). His clotting activity was initially impaired (3%) but returned to baseline (8-10%) within four weeks. MHC Class II tetramers were used to analyze his CD4 T cells, which were stimulated with peptides spanning the C2 domain. Responses of total and CD25-depleted CD4 cells to sequences containing A2201 (native), P2201 (hemophilic), and other predicted T-cell epitopes were evaluated. RESULTS AND CONCLUSIONS: An HLA-DRA-DRB1*0101 restricted T-cell epitope containing the wild-type A2201 sequence was identified. Interestingly, peptides containing A2201 were recognized by CD4 T cells at all time points, whereas a P2201 peptide was recognized only near the initial peak response. The responsiveness of CD25-depleted CD4 cells to an A2201 peptide was enhanced 11 and 19 weeks following inhibitor detection, suggesting the possible involvement of CD4+CD25+ regulatory T cells in modulating immune responses. Patient-derived T-cell clones proliferated in response to C2 protein and to peptides containing A2201 but not P2201.

ELISA system for detection of immune responses to FVIII: a study of 246 samples and correlation with the Bethesda assay.

Inhibitors of FVIII are usually IgG polyclonal antibodies that develop as alloimmune responses in patients with congenital haemophilia A or as autoimmune responses resulting in acquired haemophilia. Their recognition can be difficult, especially when the titre is low. Furthermore, results from a Bethesda assay often require several days as samples are referred to a specialty laboratory. The aim of this study is to assess the utility of an ELISA system for detecting immune responses to FVIII. A total of 246 plasma samples submitted from 176 individuals with immune responses to FVIII, as verified with the Bethesda assay, and samples from 50 control subjects were tested for the presence of FVIII-specific IgG using an ELISA-based assay. Paired sera from 18 of the patients were also tested by the ELISA. Of the 246 samples that were positive for a FVIII inhibitor by the Bethesda assay, 235 (95.5%) were also positive by ELISA. The regression coefficient, using Log BU was r = 0.82. The correlation data were strengthened when 27 inhibitor samples were diluted further. There was a strong correlation between ELISA results for the 18-paired serum and plasma samples (r = 0.99). There is a strong correlation between the ELISA and Bethesda methods in detecting immune responses to FVIII. The ELISA provides rapid screening that could be available well in advance of confirmation by the Bethesda assay.

Induction of partial immune tolerance to factor VIII through prior mucosal exposure to the factor VIII C2 domain.

BACKGROUND: The development of anti-factor VIII (FVIII) neutralizing antibodies (inhibitors) is a significant obstacle to FVIII replacement therapy. OBJECTIVE: As mucosal administration of an antigen may induce immune tolerance we have evaluated the efficacy of mucosal antigen exposure to achieve tolerance to FVIII. METHODS: We investigated the effects of oral and nasal administration of the purified FVIII C2 domain (FVIII-C2) to FVIII-deficient BALB/c mice prior to FVIII protein challenge. Mice received oral or nasal doses of FVIII-C2, followed by a subcutaneous challenge of either FVIII-C2 or FVIII. The development of anti-FVIII inhibitors, cytokine production by splenocytes in vitro, and adoptive transfer assays were analyzed. RESULTS AND CONCLUSIONS: Mucosal administration of FVIII-C2 decreases the titer of anti-FVIII-C2 inhibitors after FVIII-C2 challenge, and decreases the percentage of FVIII-C2 specific antibodies after challenge with full-length FVIII. Tolerance induction to FVIII-C2 is associated with increased IL-10 production by splenocytes in vitro, and can be adoptively transferred to naïve mice. This study is the first to demonstrate that tolerance to the FVIII-C2 domain can be induced via the mucosal route. Based on these results, the potential use of FVIII-specific mucosal tolerance induction as an immunotherapy treatment for anti-FVIII inhibitor development warrants further investigation.

Aspects of design, structure, performance and operation of reed beds--eight years' experience in northeastern New South Wales, Australia.

Reed beds (horizontal subsurface flow constructed wetlands) have been employed as secondary treatment devices in on-site and decentralised wastewater management systems in the northeast of the Australian state of New South Wales (NSW) for over a decade. This paper summarises some of the practical and research findings that have come to light in that time. Experience with various aspects of reed bed structure is discussed. A study of the evaporative performance of four small beds planted with Phragmites australis yielded an annual crop factor of 2.6. A total of 28 studies on reed beds treating a variety of commonly encountered wastewater streams yielded the following mean pollutant removal efficiencies: total suspended solids (TSS) 83%, biochemical oxygen demand (BOD) 81%, total nitrogen (TN) 57%, total phosphorus (TP) 35% and faecal coliforms (FC) 1.9 logs. The reed bed is becoming the preferred on-site technology for removing TN and BOD and polishing TSS from primary settled domestic wastewater. Sizing beds for a residence time of approximately five days has become standard practice. A study of six reed beds found six different species of earthworm present, mainly Perionyx excavatus (Indian Blue). A mesocosm experiment subsequently showed that the worms were translocating clogging material from the substrate interstices to the surface of the bed thereby indicating a possible method for prolonging reed bed life.

Insulin-like growth factor binding protein-3 generation as a measure of GH sensitivity.

A total of 198 subjects were randomized to either high-dose (0.05 mg/kg.d) or low-dose (0.025 mg/kg.d) GH for 7 d; the alternate dose was then received after a 2-wk washout period. Groups included in the study were: normal, GH-insensitive (GHI; homozygous for the E180 splice mutation); heterozygous GHI (carriers of the E180 splice mutation); GH-deficient; and idiopathic short stature. Serum IGF binding protein-3 (IGFBP-3) concentrations (collected on d 1, 5, and 8 of treatment weeks) were GH-dependent, with significant elevation by d 5 of treatment, regardless of dose, in all normal subjects. GHI subjects had low baseline IGFBP-3 and poor or no response to either low- or high-dose GH. Heterozygous subjects, however, did not differ from age-matched normals with regard to IGFBP-3 generation. All GH-deficient subjects had subnormal baseline concentrations of IGFBP-3; most, but not all, were able to generate levels into normal ranges by 8 d of therapy. Children with idiopathic short stature showed a better response in IGFBP-3 generation compared with that previously observed with IGF-I, reaching concentrations in normal range with either dose of GH, suggesting that any GHI in this group is relatively limited to IGF-I production. For the diagnosis of GHI, the highest sensitivity (100%) and specificity (92%) was found on d 8 of the high-dose GH-IGFBP-3 generation test. Failure to raise both IGF-I and IGFBP-3 lowered sensitivity to 82-86% with low-dose GH, and 86-91% with high-dose GH.

Anterior universal spine system for adolescent idiopathic scoliosis: a follow-up study using scoliometer, real-time ultrasound and radiographs.

Nine patients with AIS treated surgically with anterior USS instrumentation were examined by several methods pre-operatively and at each of 8 weeks, 1 year and 2 years after surgery (mean age 14.6 years, girls 7, boys 2, thoracolumbar 7, lumbar 1, thoracic 1, left 7, right 2). The methods used were (1) Scoliometer to measure angle of trunk inclinations (ATIs) in the standing forward bending position at each of 10 levels and converted to 18 levels by a computer program, (2) real-time ultrasound in the prone position of laminal rotations at each of 1 8 levels from TI-SI, and (3) anteroposterior radiographs in the standing erect position measured for each of Cobb angle, segmental vertebral rotation (Perdriolle) and segmental vertebral translation from the Ti-Si line (horizontal translation of each vertebral centroid from the T1-S1 line). The findings were plotted graphically and segmentally for each of Scoliometer ATJs, ultrasound laminal rotations, and radiographic vertebral rotations and translations. Findings. Graphical representation of the data shows that the improvement brought about by surgery is most clearly and consistently evident for segmental vertebral translation. The statistical analysis shows that the radiological parameters (Cobb angle, apical vertebral rotation and apical vertebral translation) and ultrasound spinal (laminal) rotation do not change detectably in follow-up. The Scoliometer ATI findings show an increase from 4 degrees (at 8 weeks) to 7 degrees (at 2 years) which is statistically significant. The evidence from this small sample of patients is consistent with the view that the compared with posterior USS, anterior USS surgery for AIS results in (1) similar initial rib hump correction, and (2) less rib hump reassertion during follow-up. More data are needed to evaluate these views.

The IGF-I generation test revisited: a marker of GH sensitivity.

IGF-I generation tests were developed over 20 yr ago and are currently used in differentiating GH insensitivity (GHI) from other disorders characterized by low serum IGF-I. Nevertheless, generation tests have never been adequately characterized, and insufficient normative data are available. One hundred and ninety-eight subjects [including normal subjects; subjects with GHI, GH deficiency (GHD), and idiopathic short stature (ISS); and heterozygotes for the E180 splice GH receptor mutation] were randomized to self-administration of either a high (0.05 mg/kg x d) or a low (0.025 mg/kg x d) dose of GH for 7 d. After a 2-wk washout period, they received the alternate dose. Samples were collected on d 1, 5, and 8 of each treatment period. In normal individuals, IGF-I generation was GH dependent at all ages, and little advantage was observed in using the higher dose of GH or extending beyond the d 5 sample. Some GHD patients had IGF-I levels, both baseline and stimulated, that overlapped levels in the verified GHI patients. Subjects heterozygous for the E180 GH receptor splice mutation did not show a decreased responsiveness to GH. ISS patients had low-normal IGF-I levels that did not stimulate beyond the baseline normative ranges for age. These data provide the first large scale effort to provide preliminary normative IGF generation data and evaluate the GH sensitivity of patients with GHI, GHD, and ISS.

Usefulness of different biochemical markers of the insulin-like growth factor (IGF) family in diagnosing growth hormone excess and deficiency in adults.

The diagnostic approach to acromegaly and GH deficiency frequently includes measurement of several components of the insulin-like growth factor (IGF) system. IGF-I levels are reported to be good predictors of active and cured acromegaly, but are commonly found within the normal age-adjusted range in adult GH-deficient (GHD) patients. Circulating concentrations of IGF-binding protein-3 (IGFBP-3), acid-labile subunit (ALS), and free IGF-I reflect the GH secretory status, but their diagnostic accuracy is still debated. In this study serum levels of total and free IGF-I, IGFBP-3, ALS, and IGFBP-3-IGF-I and IGFBP-3-ALS complexes were determined in patients previously diagnosed with active (n = 67) or inactive (n = 16) acromegaly and adult GHD (n = 34) and compared with results obtained in 58 healthy controls. In healthy subjects, IGF-I, IGFBP-3, ALS, and both IGFBP-3 complexes declined with age; a correlation was found between IGF-I and IGFBP-3 (r = 0.59; P < 0.001), ALS (r = 0.67; P < 0.001), and free IGF-I (r = 0.40; P < 0.05). Active acromegalic patients showed a significant increase in all parameters tested. IGF-I concentrations were above +2 SD in 100% of patients, whereas slightly lower sensitivities were shown for IGFBP-3 (85%), ALS (88%), and free IGF-I (94%). In this group, IGF-I exhibited a slightly higher correlation with IGFBP-3 (r = 0.83; P < 0.001) than with ALS levels (r = 0.78; P < 0.001). In cured acromegalic patients, we observed the normalization of all parameters but free IGF-I levels. Adult GHD patients showed a significant reduction of all hormones. Unlike active acromegalic patients, all parameters had only a modest sensitivity in GHD; suppression below -2 SD was observed in 41% of GHD patients for IGF-I, 47% for IGFBP-3, 32% for ALS, and 35% for free IGF-I measurements. Previous radiotherapy and GH peak response below 3 microg/L were associated with significantly lower IGF-I, IGFBP-3, and ALS levels. IGF-I levels were significantly correlated to ALS (r = 0.68; P < 0.001) and IGFBP-3 (r = 0.64; P < 0.001) as well as with free IGF-I (r = 0.67; P < 0.001) levels. By multiple regression analysis, the number of anterior pituitary hormones impaired was the most predictive indicator of IGF-I, IGFBP-3, and free IGF-I levels in GHD patients; conversely, the GH peak response better anticipated ALS concentrations. The pattern of IGFBP-3 complexes paralleled previous hormonal findings. In active acromegalic patients, IGFBP-3-IGF-I levels were 5.4-fold higher than in controls and were above +2 SD in 95% of patients, whereas IGFBP-3-ALS levels were elevated in 15% of cases. On the other hand, both IGFBP-3 complexes were able to predict GHD in only a minority of cases. Taken together, these data support the diagnostic role of IGF-I in acromegaly and suggest that free IGF-I and the IGFBP-3-IGF-I complex can assist diagnostic strategies in this condition. All markers are of limited predictive value in adult GHD, as hormonal values are commonly found within the normal limits. In these patients, low IGFBP-3 and IGF-I concentrations can add further clinical information on the residual GH activity.

Structure of a factor VIII C2 domain-immunoglobulin G4kappa Fab complex: identification of an inhibitory antibody epitope on the surface of factor VIII.

The development of an immune response to infused factor VIII is a complication affecting many patients with hemophilia A. Inhibitor antibodies bind to antigenic determinants on the factor VIII molecule and block its procoagulant activity. A patient-derived inhibitory immunoglobulin G4kappa antibody (BO2C11) produced by an immortalized memory B-lymphocyte cell line interferes with the binding of factor VIII to phospholipid surfaces and to von Willebrand factor. The structure of a Fab fragment derived from this antibody complexed with the factor VIII C2 domain was determined at 2.0 A resolution. The Fab interacts with solvent-exposed basic and hydrophobic side chains that form a membrane-association surface of factor VIII. This atomic resolution structure suggests a variety of amino acid substitutions in the C2 domain of factor VIII that might prevent the binding of anti-C2 inhibitor antibodies without significantly compromising the procoagulant functions of factor VIII.

Regulation of somatic growth by the p160 coactivator p/CIP.

A family of p160 coactivators was initially identified based on ligand-dependent interactions with nuclear receptors and thought to function, in part, by recruiting CREB-binding protein/p300 to several classes of transcription factors. One of the p160 factors, p/CIP/AIB1, often amplified and overexpressed in breast cancer, also exhibits particularly strong interaction with CREB-binding protein/p300. In this manuscript, we report that p/CIP, which exhibits regulated transfer from cytoplasm to nucleus, is required for normal somatic growth from embryonic day 13.5 through maturity. Our data suggest that a short stature phenotype of p/CIP gene-deleted mice reflect both altered regulation of insulin-like growth factor-1 (IGF-1) gene expression in specific tissues and a cell-autonomous defect of response to IGF-1, including ineffective transcriptional activities by several classes of regulated transcription factors under specific conditions. The actions of p/CIP are therefore required for full expression of a subset of genes critical for regulating physiological patterns of somatic growth in mammals.