Development of ISB 1442, a CD38 and CD47 bispecific biparatopic antibody innate cell modulator for the treatment of multiple myeloma.

Antibody engineering can tailor the design and activities of therapeutic antibodies for better efficiency or other advantageous clinical properties. Here we report the development of ISB 1442, a fully human bispecific antibody designed to re-establish synthetic immunity in CD38+ hematological malignancies. ISB 1442 consists of two anti-CD38 arms targeting two distinct epitopes that preferentially drive binding to tumor cells and enable avidity-induced blocking of proximal CD47 receptors on the same cell while preventing on-target off-tumor binding on healthy cells. The Fc portion of ISB 1442 is engineered to enhance complement dependent cytotoxicity, antibody dependent cell cytotoxicity and antibody dependent cell phagocytosis. ISB 1442 thus represents a CD47-BsAb combining biparatopic targeting of a tumor associated antigen with engineered enhancement of antibody effector function to overcome potential resistance mechanisms that hamper treatment of myeloma with monospecific anti-CD38 antibodies. ISB 1442 is currently in a Phase I clinical trial in relapsed refractory multiple myeloma.

Does Trans-radial Longitudinal Compression Influence Myoelectric Control?

BACKGROUND: Existing trans-radial prosthetic socket designs are not optimised to facilitate reliable myoelectric control. Many socket designs pre-date the introduction of myoelectric devices. However, socket designs featuring improved biomechanical stability, notably longitudinal compression sockets, have emerged in more recent years. Neither the subsequent effects, if any, of stabilising the limb on myoelectric control nor in which arrangement to apply the compression have been reported. METHODOLOGY: Twelve able-bodied participants completed two tasks whilst wearing a longitudinal compression socket simulator in three different configurations: 1) compressed, where the compression strut was placed on top of the muscle of interest, 2) relief, where the compression struts were placed either side of the muscle being recorded and 3) uncompressed, with no external compression. The tasks were 1) a single-channel myoelectric target tracking exercise, followed by 2), a high-intensity grasping task. The wearers' accuracy during the tracking task, the pressure at opposing sides of the simulator during contractions and the rate at which the limb fatigued were observed. FINDINGS: No significant difference between the tracking-task accuracy scores or rate of fatigue was observed for the different compression configurations. Pressure recordings from the compressed configuration showed that pressure was maintained at opposing sides of the simulator during muscle contractions. CONCLUSION: Longitudinal compression does not inhibit single-channel EMG control, nor improve fatigue performance. Longitudinal compression sockets have the potential to improve the reliability of multi-channel EMG control due to the maintenance of pressure during muscle contractions.

Health care providers' weight management practices for adolescent obesity and alignment with clinical practice guidelines: a multi-centre, qualitative study.

BACKGROUND: Clinical practice guidelines (CPGs) include evidence-based recommendations for managing obesity in adolescents. However, information on how health care providers (HCPs) implement these recommendations in day-to-day practice is limited. Our objectives were to explore how HCPs deliver weight management health services to adolescents with obesity and describe the extent to which their reported practices align with recent CPGs for managing pediatric obesity. METHODS: From July 2017 to January 2018, we conducted a qualitative study that used purposeful sampling to recruit HCPs with experience in adolescent weight management from multidisciplinary, pediatric weight management clinics in Edmonton and Ottawa, Canada. Data were collected using audio-recorded focus groups (4-6 participants/group; 60-90 min in length). We applied inductive, semantic thematic analysis and the congruent methodological approach to analyze our data, which included transcripts, field notes, and memos. Qualitative data were compared to recent CPGs for pediatric obesity that were published by the Endocrine Society in 2017. Of the 12 obesity 'treatment-related' recommendations, four were directly relevant to the current study. RESULTS: Data were collected through three focus groups with 16 HCPs (n = 10 Edmonton; n = 6 Ottawa; 94% female; 100% Caucasian), including dietitians, exercise specialists, nurses, pediatricians, psychologists, and social workers. We identified three main themes that we later compared with CPG recommendations, including: (i) discuss realistic expectations regarding weight management (e.g., shift focus from weight to health; explore family cohesiveness; foster delayed vs instant gratification), (ii) personalize weight management (e.g., address personal barriers to change; consider developmental readiness), and (iii) exhibit non-biased attitudes and practices (e.g., de-emphasize individual causes of obesity; avoid making assumptions about lifestyle behaviors based on weight). Based on these qualitative findings, HCPs applied all four CPG recommendations in their practices. CONCLUSIONS: HCPs provided practical insights into what and how they delivered weight management for adolescents, which included operationalizing relevant CPG recommendations in their practices.

End-user perspectives to inform policy and program decisions: a qualitative and quantitative content analysis of lifestyle treatment recommendations by adolescents with obesity.

BACKGROUND: Lifestyle modifications represent the first line of treatment in obesity management; however, many adolescents with obesity do not meet lifestyle recommendations. Given that adolescents are rarely consulted during health policy development and in the design of lifestyle interventions, their first-hand experiences, preferences, and priorities may not be represented. Accordingly, our purpose was to explore adolescents' lifestyle treatment recommendations to inform policy and program decisions. METHODS: Conducted from July 2017 to January 2018, this study adhered to a qualitative, crosslanguage, patient-oriented design. We recruited 19 13-17-year-old adolescents (body mass index [BMI] ≥85th percentile) seeking multidisciplinary treatment for obesity in geographically and culturally diverse regions of Canada. Adolescents participated in one-on-one, in-person, semi-structured interviews in English or French. Interviews were audio-recorded, transcribed verbatim, managed using NVivo 11, and analyzed using quantitative and qualitative content analysis by two independent researchers. RESULTS: Adolescents' recommendations were organized into five categories, each of which denotes health as a collective responsibility: (i) establish parental support within limits, (ii) improve accessibility and availability of 'healthy foods', (iii) limit deceptive practices in food marketing, (iv) improve accessibility and availability of varied physical activity opportunities, and (v) delay school start times. Respect for individual autonomy and decision-making capacity were identified as particularly important, however these were confronted with adolescents' partial knowledge on nutrition and food literacy. CONCLUSIONS: Adolescents' recommendations highlighted multi-level, multi-component factors that influenced their ability to lead healthy lifestyles. Uptake of these recommendations by policy-makers and program developers may be of added value for lifestyle treatment targeting adolescents with obesity.

Feasibility, user experiences, and preliminary effect of Conversation Cards for Adolescents© on collaborative goal-setting and behavior change: protocol for a pilot randomized controlled trial.

BACKGROUND: Adolescents and providers can benefit from practical tools targeting lifestyle modification for obesity prevention and management. We created Conversation Cards for Adolescents© (CCAs), a patient-centered communication and behavior change tool for adolescents and providers to use in clinical practice. The purpose of our study is to (i) assess the feasibility of CCAs in a real-world, practice setting to inform full-scale trial procedures, (ii) assess user experiences of CCAs, and (iii) determine the preliminary effect of CCAs on changing behavioral and affective-cognitive outcomes among adolescents. METHODS: Starting in early 2019, this prospective study is a nested mixed-methods, theory-driven, and pragmatic pilot randomized controlled trial with a goal to enroll 50 adolescents (13-17 years old) and 9 physicians practicing at the Northeast Community Health Centre in Edmonton, Alberta, Canada. Adolescents will collaboratively set one S.M.A.R.T. (specific, measurable, attainable, realistic, timely) goal with their physician to implement over a 3-week period; however, only those randomized to the experimental group will use CCAs to inform their goal. Outcome assessments at baseline and follow-up (3 weeks post-baseline) will include behavioral, affective-cognitive, and process-related outcomes. DISCUSSION: In examining the feasibility, user experiences, and preliminary effect of CCAs, our study will add contributions to the obesity literature on lifestyle modifications among adolescents in a real-world, practice setting as well as inform the scalability of our approach for a full-scale effectiveness randomized controlled trial on behavior change. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT03821896.

Barriers to and enablers of healthy lifestyle behaviours in adolescents with obesity: a scoping review and stakeholder consultation.

Healthy lifestyle behaviours are key to successful weight management, but have proven to be challenging to attain for adolescents with obesity. The purpose of our scoping review was to (i) describe barriers and enablers that adolescents with obesity encounter for healthy nutrition, physical activity, sedentary behaviour and sleep habits and (ii) identify gaps in the literature. We adhered to established methodology for scoping reviews. Six databases were searched (1980-June 2016) for original articles published in English or French that focused on lifestyle behaviours of 13- to 17-year-olds in paediatric weight management. Following screening and data extraction, findings of selected articles were synthesized thematically using a social ecological framework. Stakeholder consultation (n = 20) with adolescents with obesity and health professionals was completed to enhance methodological rigour. Our search yielded 17 articles for inclusion, including 546 unique participants. Barriers to healthy nutrition and physical activity were more consistently related to individual-level and interpersonal-level factors; enablers tended to be linked with interpersonal-level factors. Knowledge gaps identified related to sedentary behaviour and sleep as well as environmental and policy levels of influence. Our review revealed that some barriers and enablers were unique to adolescents with obesity, which were either within or beyond their control. These findings highlight the importance of multilevel interventions to enable healthy lifestyle behaviours for weight management.

Structural reorganization of cylindrical nanoparticles triggered by polylactide stereocomplexation.

Co-crystallization of polymers with different configurations/tacticities provides access to materials with enhanced performance. The stereocomplexation of isotactic poly(L-lactide) and poly(D-lactide) has led to improved properties compared with each homochiral material. Herein, we report the preparation of stereocomplex micelles from a mixture of poly(L-lactide)-b-poly(acrylic acid) and poly(D-lactide)-b-poly(acrylic acid) diblock copolymers in water via crystallization-driven self-assembly. During the formation of these stereocomplex micelles, an unexpected morphological transition results in the formation of dense crystalline spherical micelles rather than cylinders. Furthermore, mixture of cylinders with opposite homochirality in either THF/H2O mixtures or in pure water at 65 °C leads to disassembly into stereocomplexed spherical micelles. Similarly, a transition is also observed in a related PEO-b-PLLA/PEO-b-PDLA system, demonstrating wider applicability. This new mechanism for morphological reorganization, through competitive crystallization and stereocomplexation and without the requirement for an external stimulus, allows for new opportunities in controlled release and delivery applications.

Atomically resolved imaging of highly ordered alternating fluorinated graphene.

One of the most desirable goals of graphene research is to produce ordered two-dimensional (2D) chemical derivatives of suitable quality for monolayer device fabrication. Here we reveal, by focal series exit wave reconstruction (EWR), that C2F chair is a stable graphene derivative and demonstrates pristine long-range order limited only by the size of a functionalized domain. Focal series of images of graphene and C2F chair formed by reaction with XeF2 were obtained at 80 kV in an aberration-corrected transmission electron microscope. EWR images reveal that single carbon atoms and carbon-fluorine pairs in C2F chair alternate strictly over domain sizes of at least 150 nm(2) with electron diffraction indicating ordered domains ≥ 0.16 µm(2). Our results also indicate that, within an ordered domain, functionalization occurs on one side only as theory predicts. In addition, we show that electron diffraction provides a quick and easy method for distinguishing between graphene, C2F chair and fully fluorinated stoichiometric CF 2D phases.

ERß- and prostaglandin E2-regulated pathways integrate cell proliferation via Ras-like and estrogen-regulated growth inhibitor in endometriosis.

In endometriosis, stromal and epithelial cells from the endometrium form extrauterine lesions and persist in response to estrogen (E2) and prostaglandin E2 (PGE2). Stromal cells produce excessive quantities of estrogen and PGE2 in a feed-forward manner. However, it is unknown how estrogen stimulates cell proliferation and survival for the establishment and persistence of disease. Previous studies suggest that estrogen receptor-ß (ERß) is strikingly overexpressed in endometriotic stromal cells. Thus, we integrated genome-wide ERß binding data from previously published studies in breast cells and gene expression profiles in human endometriosis and endometrial tissues (total sample number = 81) and identified Ras-like, estrogen-regulated, growth inhibitor (RERG) as an ERß target. Estradiol potently induced RERG mRNA and protein levels in primary endometriotic stromal cells. Chromatin immunoprecipitation demonstrated E2-induced enrichment of ERß at the RERG promoter region. PGE2 via protein kinase A phosphorylated RERG and enhanced the nuclear translocation of RERG. RERG induced the proliferation of primary endometriotic cells. Overall, we demonstrated that E2/ERß and PGE2 integrate at RERG, leading to increased endometriotic cell proliferation and represents a novel candidate for therapeutic intervention.

Band gap expansion, shear inversion phase change behaviour and low-voltage induced crystal oscillation in low-dimensional tin selenide crystals.

In common with rocksalt-type alkali halide phases and also semiconductors such as GeTe and SnTe, SnSe forms all-surface two atom-thick low dimensional crystals when encapsulated within single walled nanotubes (SWNTs) with diameters below ∼1.4 nm. Whereas previous density functional theory (DFT) studies indicate that optimised low-dimensional trigonal HgTe changes from a semi-metal to a semi-conductor, low-dimensional SnSe crystals typically undergo band-gap expansion. In slightly wider diameter SWNTs (∼1.4-1.6 nm), we observe that three atom thick low dimensional SnSe crystals undergo a previously unobserved form of a shear inversion phase change resulting in two discrete strain states in a section of curved nanotube. Under low-voltage (i.e. 80-100 kV) imaging conditions in a transmission electron microscope, encapsulated SnSe crystals undergo longitudinal and rotational oscillations, possibly as a result of the increase in the inelastic scattering cross-section of the sample at those voltages.

Targeting EGFR and PI3K pathways in ovarian cancer.

BACKGROUND: The epidermal growth factor receptor (EGFR) is expressed in ovarian cancer, but agents targeting this pathway have shown little effect as single agents. This may be due to the presence of alternative pathways, particularly activation of the PI3K/Akt/MTOR pathway. METHODS: We have therefore examined the effect of inhibitors of this pathway (ZSTK474 and sirolimus) in combination with the EGFR inhibitors erlotinib and gefitinib in ovarian cancer primary cell cultures. RESULTS: The single-agent EGFR inhibitors showed little activity, although some activity was seen with the single-agent PI3K inhibitor, ZSTK474. Combinations of ZSTK474 with EGFR inhibitors showed enhanced activity with some evidence of synergy, whereas sirolimus combinations were less active. The results were not explicable on the basis of PIK3CA mutation or amplification, or PTEN loss, although one tumour with a KRAS mutation showed resistance to EGFR inhibitors. However, there was correlation of the EGFR expression with sensitivity to EGFR and resistance to PI3K active agents, and inverse correlation in the sensitivity of individual tumours to agents active against these pathways, suggesting a mechanism of action for the combination. CONCLUSION: Phase I/II clinical trials with these agents should include further pharmacodynamic endpoints and molecular characterisation to identify patients most likely to benefit from this strategy.

Ligand-activated peroxisome proliferator-activated receptor ß/δ modulates human endometrial cancer cell survival.

Endometrial cancer is the fourth most common malignancy among women and is a major cause of morbidity contributing to approximately 8,200 annual deaths in the USA. Despite advances to the understanding of endometrial cancer, novel interventions for the disease are necessary given that many tumors become refractory to therapy. As a strategy to identify novel therapies for endometrial carcinoma, in this study, we examined the contribution of the peroxisome proliferator-activated receptor ß/δ (PPARß/δ) to endometrial cancer cell proliferation and apoptosis. We found that when activated with the highly selective PPARß/δ agonists, GW0742 and GW501516, PPARß/δ inhibited the proliferation and markedly induced the apoptosis of three endometrial cancer cell lines. The specificity of the PPARß/δ-induced effects on cell proliferation and apoptosis was demonstrated using PPARß/δ-selective antagonists and PPARß/δ small interfering RNA in combination with PPARß/δ-selective agonists. Furthermore, we showed that PPARß/δ activation increased phosphatase and tensin homolog expression, which led to protein kinase B (AKT) and glycogen synthase kinase-3ß (GSK3ß) dephosphorylation, and increased ß-catenin phosphorylation associated with its degradation. Overall, our data suggest that the antitumorigenic effect of PPARß/δ activation in endometrial cancer is mediated through the negative regulation of the AKT/GSK3ß/ß-catenin pathway. These findings warrant further investigation of PPARß/δ as a therapeutic target in endometrial cancer.

Localisation of cognitive tasks used in EEG-based BCIs.

OBJECTIVE: To provide candidate electrode sites and neurophysiological reference information for cognitive tasks used in brain-computer interfacing research. METHODS: Six cognitive tasks were tested against the idle state. Data representing the idle state were collected with active cognitive task data during each recording session. Cross subject candidate electrode sites were obtained via a wrapper method based upon a sequential forward floating search algorithm. Source localisation results were obtained using sLORETA software. RESULTS: Spatial feature distributions and localisation results are presented. Primary centres of activity for motor imagery tasks are localised to the pre- and postcentral gyrus. Auditory-based tasks show activity in the middle temporal gyrus. Calculation activity was localised to the left inferior frontal gyrus and right supramarginal gyrus. Navigation imagery produced activity in the precuneus and anterior cingulate cortex. CONCLUSIONS: Spatial areas of activation suggest that arithmetic and auditory tasks show promise for pairwise discrimination based on single recording sites. sLORETA significance levels suggest that motor imagery tasks will show greatest discrimination from baseline EEG activity. SIGNIFICANCE: This is the first study to provide candidate electrode sites for multiple tasks used in brain-computer interfacing.

Generating a panel of highly specific antibodies to 20 human SH2 domains by phage display.

To demonstrate the utility of phage display in generating highly specific antibodies, affinity selections were conducted on 20 related Src Homology 2 (SH2) domains (ABL1, ABL2, BTK, BCAR3, CRK, FYN, GRB2, GRAP2, LYN, LCK, NCK1, PTPN11 C, PIK3R1 C, PLCgamma1 C, RASA1 C, SHC1, SH2D1A, SYK N, VAV1 and the tandem domains of ZAP70). The domains were expressed in Escherichia coli, purified and used in affinity selection experiments. In total, 1292/3800 of the resultant antibodies were shown to bind the target antigen. Of the 695 further evaluated in specificity ELISAs against all 20 SH2 domains, 379 antibodies were identified with unique specificity (i.e. monospecific). Sequence analysis revealed that there were at least 150 different clones with 1-19 different antibodies/antigen. This includes antibodies that distinguish between ABL1 and ABL2, despite their 89% sequence identity. Specificity was confirmed for many on protein arrays fabricated with 432 different proteins. Thus, even though the SH2 domains share a common three-dimensional structure and 20-89% identity at the primary structure level, we were able to isolate antibodies with exquisite specificity within this family of structurally related domains.

HER2 amplification status in breast cancer: a comparison between immunohistochemical staining and fluorescence in situ hybridisation using manual and automated quantitative image analysis scoring techniques.

AIMS: To compare the results of breast cancer sections with HercepTesttrade mark immunohistochemistry (IHC) scores ranging from 0 to 3+ with fluorescence in situ hybridisation (FISH) for HER2 amplification. The HER2 digital scoring application of the Micrometastasis Detection System (MDS) was used, together with manual scoring of FISH and HercepTest, to determine whether this system provides an accurate alternative. METHODS: Paraffin wax embedded sections were stained using HercepTest and analysed by eye and automated quantitative image analysis. FISH was performed using the PathVysion fluorescent probe and scored by eye and automated quantitative image analysis using MDS. RESULTS: Of 114 cases, 26% were amplified by FISH, whereas only 18% scored 3+; 32% of IHC 2+ cases were amplified by FISH, and one showed borderline amplification. Six percent of IHC negative cases (0 or 1+) were amplified by FISH, and one showed borderline amplification. Of IHC 3+ cases, 10% were non-amplified by FISH. Classification discrepancies were seen in 18% of HercepTest cases scored by eye and using the MDS system. MDS was consistent with visual FISH scoring and correctly differentiated most ambiguous visual IHC scores. CONCLUSIONS: FISH provides a more accurate and consistent scoring system for determining HER2 amplification than HercepTest. The MDS system provides a reliable, consistent alternative to visual IHC and FISH scoring. IHC is still a valuable technique to aid in identification of isolated or heterogeneous tumour populations for subsequent FISH analysis, and a combined FISH and HercepTest approach to all breast cancer cases may be the most efficient strategy.

Wound healing assessment using 20 MHz ultrasound and photography.

BACKGROUND/AIMS: To compare two non-invasive techniques of assessing wound healing, photography and high resolution ultrasound (HRUS) scanning, in experimentally induced full-thickness human skin wounds. METHODS: Punch biopsy wounds, 4 mm in diameter, were made aseptically through locally anaesthetised skin on the anterior (volar) surface of the non-dominant forearm, 3 cm below the base of the cubital fossa, of 20 human participants. The wounds were treated with a topical antibiotic and covered for 3 days with Mepore sterile dressings. Wound healing was assessed on post-operative days 3, 7, 14 and 21 from photographs and HRUS B-scans. All photographs were taken of the wound site and adjacent intact skin under standardised conditions. The prints obtained were examined visually and digitised. Digital HRUS B-scans were taken through the centre of the wound bed and the adjacent intact skin parallel to the epidermis. Using the scanner's calibrated linear measurement capability, the wound width was measured adjacent to the deep surface of the scab, at the base of the wound, and midway between these two levels. RESULTS: The wound margins were more clearly defined in the HRUS scans than in the photographs of the wounds; in some of the latter the scab masked the wound margins. Changes in the surface width of the wound were affected by the time of scab dehiscence, which varied between volunteers. There was less individual variation in the width of the base of the wound, as measured from the HRUS scans. CONCLUSIONS: In contrast to photography, which allows recording of changes in the superficial aspect of the wound only, HRUS scanning permits the quantitative assessment of structural changes deep within the wound. Temporal changes in the width of the base of the wound can be used as an indication of the progress of repair.

Recruitment and development of the follicle; the roles of the transforming growth factor-beta superfamily.

Peripheral endocrine hormones and local paracrine and autocrine factors contribute, in a coordinated fashion, to the processes of recruitment, development or atresia, selection and ovulation of follicles. Among the local ovarian factors, there is growing evidence from genetic and experimental data that many members of the transforming growth factor (TGFbeta) superfamily have a biological role to play in folliculogenesis. These members include activin, inhibin, TGFbeta, BMP, GDF9 and perhaps MIS. In this review, we discuss the potential roles of the TGFbeta superfamily members, in particular activin, during folliculogenesis. Since the actions of these factors are determined by ligand availability, receptor expression and modulation of their signal transduction pathways, we also collate information on the expression of their signalling components in the follicle. We conclude that the TGFbeta superfamily signalling pathways, in particular activin's pathway, reside in the ovary. Furthermore, follistatin and beta-glycan-components of the accessory binding protein system that modifies activin action-are also present in follicles. In the post-natal rat ovary, the changes in receptor/Smad expression coincide with granulosa cell proliferation and antrum formation. We hypothesise that these pathway components are expressed in a temporal and cell-specific manner to meet the changing demands of cells during follicular development. The analysis of the components of the signal transduction pathways of the TGFbeta family members in populations of defined follicles and the identification of activated pathways in individually stimulated follicles should help clarify the roles of the TGFbeta members in folliculogenesis.

Growth hormone improves clinical status in prepubertal children with cystic fibrosis: results of a randomized controlled trial.

OBJECTIVES: We conducted a 1-year randomized controlled trial to test the hypothesis that growth hormone (GH) improves the clinical status of children with cystic fibrosis. STUDY DESIGN: Nineteen prepubertal children were randomized to control (NonTX, n = 9) or to daily injections of GH (0.3 mg/kg/wk) (GHTX, n = 10) for 1 year. Every 3 months height, weight, and lean tissue mass were measured. Caloric intake, resting energy expenditure, pulmonary function, and respiratory muscle strength were measured every 6 months, as were total number of hospitalizations and courses of outpatient intravenous antibiotics. RESULTS: The GHTX group had significantly greater height, height velocity (NonTX = 3.8 +/- 1.4 cm/y, GHTX = 8.1 +/- 2.4 cm/y; P =.002), weight, weight velocity (NonTX = 2.1 +/- 0.9 kg/y, GHTX = 4.5 +/- 1.1 kg/y; P =.004), and change in lean tissue mass (NonTX = 2.1 +/- 1.6 kg, GHTX = 4.7 +/- 1.7 kg; P =.01) analyzed by the Student t test. The GHTX group had significant improvement in delta forced vital capacity compared with the year before study, and respiratory muscle strength improved. The number of hospitalizations and outpatient intravenous antibiotic courses significantly decreased in the GHTX group but did not change in the NonTX group. No subject had development of cystic fibrosis-related diabetes. CONCLUSIONS: Results of the first randomized controlled trial of GH treatment in cystic fibrosis indicate that GH improves growth and clinical status.

Growth hormone decreases protein catabolism in children with cystic fibrosis.

Despite aggressive nutritional therapy, low body weight and protein catabolism are common problems in children with cystic fibrosis. Previous studies by our group and others have demonstrated improvement in both height and weight in children with cystic fibrosis who were treated with human recombinant GH, and our group has recently documented improved clinical status and lean tissue mass as well. The purpose of this report is to summarize our findings of the effect of GH on whole body protein kinetics in cystic fibrosis and to relate these findings to changes in TNF-alpha levels. We conducted a 1-yr study of 19 prepubertal children with cystic fibrosis (age 7-12 yr, all <94% of ideal body weight). Ten children were randomly assigned to take daily injections of GH (0.3 mg/kg.wk), and nine were randomly assigned to be controls. Baseline results from the subjects with cystic fibrosis were compared with results obtained from nine age- and gender-matched healthy children. Whole body protein turnover was measured at baseline and every 6 months using the stable isotope [1-(13)C]leucine and mass spectrometric analysis. Leucine rate of appearance, a measure of protein catabolism, was similar in both cystic fibrosis subgroups at baseline and was significantly higher than in the control children without cystic fibrosis. Treatment with GH resulted in a significantly lower leucine rate of appearance, as well as significantly lower leucine oxidation. The rate of protein synthesis, as calculated from these numbers, actually decreased in the cystic fibrosis subgroup. TNF-alpha levels were higher in both cystic fibrosis subgroups than in controls and correlated with leucine rate of appearance. The results of this study suggest that one reason GH improves body weight and lean tissue mass is due to improved whole body protein catabolism and improved efficiency of whole body protein kinetics.