Larval nutritional-stress and tolerance to extreme temperatures in the peach fruit fly, Bactrocera zonata (Diptera: Tephritidae)

Within the factors affecting insect tolerance to extreme environmental conditions, insect nutrition, particularly of immature stages, has received insufficient attention. In the present study, we address this gap by investigating the effects of larval nutrition on heat and cold tolerance of adult Bactrocera zonata - an invasive, polyphagous fruit fly pest. We manipulated the nutritional content in the larval diet by varying the amount of added yeast (2-10% by weight), while maintaining a constant sucrose content. Adults derived from the different larval diets were tested for their tolerance to extreme heat and cold stress. Restricting the amount of yeast reduced the efficacy of the larval diet (i.e. number of pupae produced per g of diet) as well as pupal and adult fresh weight, both being significantly lower for yeast-poor diets. Additionally, yeast restriction during the larval stage (2% yeast diet) significantly reduced the amount of protein but not lipid reserves of newly emerged males and females. Adults maintained after emergence on granulated sugar and water for 10 days were significantly more tolerant to extreme heat (i.e. knock-down time at 42 ^oC) when reared as larvae on yeast-rich diets (8% and 10% yeast) compared to counterparts developing on a diet containing 2% yeast. Nevertheless, the composition of the larval diet did not significantly affect adult survival following acute cold stress (exposure to -3°C for 2 hrs.). These results are corroborated by previous findings on Drosophilid flies. Possible mechanisms leading to nutrition-based heat-tolerance in flies are discussed.

A mitochondria-regulated p53-CCF circuit integrates genome integrity with inflammation

Genomic instability and inflammation are distinct hallmarks of aging, but the connection between them is poorly understood. Understanding their interrelationship will help unravel new mechanisms and therapeutic targets of aging and age-associated diseases. Here we report a novel mechanism directly linking genomic instability and inflammation in senescent cells, through a mitochondria-regulated molecular circuit that connects the p53 tumor suppressor and cytoplasmic chromatin fragments (CCF), a driver of inflammation through the cGAS-STING pathway. Activation or inactivation of p53 by genetic and pharmacologic approaches showed that p53 suppresses CCF accumulation and the downstream inflammatory senescence-associated secretory phenotype (SASP), independent of its effects on cell cycle arrest. p53 activation suppressed CCF formation by promoting DNA repair, reflected in maintenance of genomic integrity, particularly in subtelomeric regions, as shown by single cell genome resequencing. Activation of p53 by pharmacological inhibition of MDM2 in old mice decreased features of SASP in liver, indicating a senomorphic role in vivo . Remarkably, mitochondria in senescent cells suppressed p53 activity by promoting CCF formation and thereby restricting ATM-dependent nuclear DNA damage signaling. These data provide evidence for a mitochondria-regulated p53-CCF circuit in senescent cells that controls DNA repair, genome integrity and inflammatory SASP, and is a potential target for senomorphic healthy aging interventions.

IgG Epitopes Processed and Presented by IgG+ B Cells Induce Suppression by Human Thymic-Derived Regulatory T Cells

We described a human regulatory T cell (Treg) population activated by IgG⁺ B cells presenting peptides of the heavy C region (Fc) via processing of the surface IgG underlying a model for B cell-Treg cooperation in the human immune regulation. Functionally, Treg inhibited the polarization of naive T cells toward a proinflammatory phenotype in both a cognate and a noncognate fashion. Their fine specificities were similar in healthy donors and patients with rheumatoid arthritis, a systemic autoimmune disease. Four immunodominant Fc peptides bound multiple HLA class II alleles and were recognized by most subjects in the two cohorts. The presentation of Fc peptides that stimulate Treg through the processing of IgG by dendritic cells (DC) occurred in myeloid DC classical DC 1 and classical DC 2. Different routes of Ag processing of the IgG impacted Treg expansion in rheumatoid arthritis patients.

Elongated neutrophil-derived structures are blood-borne microparticles formed by rolling neutrophils during sepsis

Rolling neutrophils form tethers with submicron diameters. Here, we report that these tethers detach, forming elongated neutrophil-derived structures (ENDS) in the vessel lumen. We studied ENDS formation in mice and humans in vitro and in vivo. ENDS do not contain mitochondria, endoplasmic reticulum, or DNA, but are enriched for S100A8, S100A9, and 57 other proteins. Within hours of formation, ENDS round up, and some of them begin to present phosphatidylserine on their surface (detected by annexin-5 binding) and release S100A8-S100A9 complex, a damage-associated molecular pattern protein that is a known biomarker of neutrophilic inflammation. ENDS appear in blood plasma of mice upon induction of septic shock. Compared with healthy donors, ENDS are 10-100-fold elevated in blood plasma of septic patients. Unlike neutrophil-derived extracellular vesicles, most ENDS are negative for the tetraspanins CD9, CD63, and CD81. We conclude that ENDS are a new class of bloodborne submicron particles with a formation mechanism linked to neutrophil rolling on the vessel wall.

0507 Mobile Cognitive Behavioral Therapy is Efficient in Improving Sleep in Students

Introduction

Academic achievements and social life on campus represent the main focus for students, while sleep is neglected. The emergence of social media, gaming reduces sleep opportunity, quality and ability. Students are sleep challenged and prone to develop chronic sleep difficulties in later life. Cognitive behavioral interventions are recognized as effective for insomnia and circadian misalignment. We aimed at detecting sleep difficulties, related habits, and at testing the efficacy of a mobile app in improving sleep in students with insomnia symptoms.

Methods

Observational study of US students who approached wellness staff and were offered the Refresh by Sleeprate mobile app that provides a sleep assessment followed by weekly cycles of personalized digital cognitive and behavioral reframing. The app collects perceived, and optional objective sleep data acquired using wearable devices. 892 students aged 18-30 years registered an account between Jan 1 and Oct 30, 2019. The study reports engagement data and outcomes of the assessment and the digital intervention.

Results

507 completed their assessment (6.2 avg nights). 69% presented insomnia symptoms with or without circadian misalignment, 8% circadian misalignment, 12% sleep deprivation, 11% poor sleep hygiene. 192 (55.3% of students with insomnia symptoms) completed at least one week of intervention (5.6 weekly avg nights, 28 avg total nights). Sleep Latency (SL) in minutes decreased from 28.8 (21.5) (Mean/SD) to 22.1 (19.3), p<0.001. When the initial mean SL was longer than 30 minutes, the improvement was larger, from 53.9 (20.8) to 32.7 (25.4) (p<0.001). Mean perceived Wake After Sleep Onset (WASO) longer than 30 minutes decreased from 46.3 (19.0) to 35.8 (21.4), p<0.05. Sleep Efficiency (SE) increased by 1.6% (p<0.002) for all, and by 7.1% (p<0.001) for SE<85%.

Conclusion

The mobile app used reveals sleep problems and is efficient in improving insomnia symptoms in those who remain engaged. 55% of those who started the program also completed it. Engagement remains the main barrier to sleep improvement at scale.

Support

N/A

0206 Sleep Opportunity and Duration are Related to Risk Injury in Elite Athletes

Introduction

Sleep is essential to musculoskeletal recovery, acquisition of new skills and emotional regulation in athletes. Insufficient sleep is detrimental to performance. Recent publications indicate that sleep duration is related to risk for injury in young athletes. We aimed at analyzing the relation between sleep opportunity and duration and the likelihood of an injury among adult elite athletes.

Methods

We studied 7,237 nights recorded with the Sleeprate application by 71 adult elite athletes from diverse sports, during the period September 2018-October 2019. Night recordings included perceived and measured sleep parameters. In addition, athletes reported their previous day nap duration, injuries and illness status. Out of the total number of nights, 4,205 included reported injury status with no injury and no illness for the previous night. Nightly total time in bed (TIB), TIB including reported naps (TIB24hr) and measured total sleep time (TST) were examined.

Results

Average TIB was significantly shorter (508±77 minutes, mean±STD) in healthy days preceding injuries than in healthy days preceding days with no injury (525±70 minutes, p<.001). Similar results were found when comparing the TIB24hr (injury: 517±83 minutes, no injury: 543±76 minutes, p<.001) and TST (injury: 443±72 minutes, no injury: 457±69 minutes, p<.001).

Conclusion

Average sleep opportunities of the elite athletes in this study were in accordance with their age and workouts load. The time athletes allow themselves as an opportunity for sleep is inversely correlated to the chances of developing an injury. These findings corroborate published research regarding sleep duration and risk of injury in athletes, yet our findings are based on real life data of elite athletes, and demonstrate the importance of sleep as part of the elite or professional athlete’s routine, suggesting that even as little as around 20 minutes of added sleep may be efficient in preventing injury.

Support

N/A

Varroa chemosensory proteins: some are conserved across Arthropoda but others are arachnid specific

The tight synchronization between the life cycle of the obligatory parasitic mite Varroa destructor (Varroa) and its host, the honeybee, is mediated by honeybee chemical stimuli. These stimuli are mainly perceived by a pit organ located on the distal part of the mite's foreleg. In the present study, we searched for Varroa chemosensory molecular components by comparing transcriptomic and proteomic profiles between forelegs from different physiological stages, and rear legs. In general, a comparative transcriptomic analysis showed a clear separation of the expression profiles between the rear legs and the three groups of forelegs (phoretic, reproductive and tray-collected mites). Most of the differentially expressed transcripts and proteins in the mite's foreleg were previously uncharacterized. Using a conserved domain approach, we identified 45 transcripts with known chemosensory domains belonging to seven chemosensory protein families, of which 14 were significantly upregulated in the mite's forelegs when compared to rear legs. These are soluble and membrane bound proteins, including the somewhat ignored receptors of degenerin/epithelial Na+ channels and transient receptor potentials. Phylogenetic clustering and expression profiles of the putative chemosensory proteins suggest their role in chemosensation and shed light on the evolution of these proteins in Chelicerata.

Toolbox of Fluorescent Probes for Parallel Imaging Reveals Uneven Location of Serine Proteases in Neutrophils

Neutrophils, the front line defenders against infection, express four serine proteases (NSPs) that play roles in the control of cell-signaling pathways and defense against pathogens and whose imbalance leads to pathological conditions. Dissecting the roles of individual NSPs in humans is problematic because neutrophils are end-stage cells with a short half-life and minimal ongoing protein synthesis. To gain insight into the regulation of NSP activity we have generated a small-molecule chemical toolbox consisting of activity-based probes with different fluorophore-detecting groups with minimal wavelength overlap and highly selective natural and unnatural amino acid recognition sequences. The key feature of these activity-based probes is the ability to use them for simultaneous observation and detection of all four individual NSPs by fluorescence microscopy, a feature never achieved in previous studies. Using these probes we demonstrate uneven distribution of NSPs in neutrophil azurophil granules, such that they seem to be mutually excluded from each other, suggesting the existence of unknown granule-targeting mechanisms.

Polymer particle shape independently influences binding and internalization by macrophages

The interaction of macrophages with micro and nanoparticles (MNPs) is important because these cells clear particles from the circulation, and because they are potential therapeutic targets in inflammatory conditions, atherosclerosis and cancer. Therefore, an understanding of the features of MNPs that influence their interaction with macrophages may allow optimization of their properties for enhanced drug delivery. In this study, we show that particle shape impacts phagocytosis by macrophages, and more importantly, that particle shape and size separately impact attachment and internalization. The study provides a methodology for further exploring how particle shape can be controlled to achieve desired attachment and internalization. The results of the study also give mechanistic guidance on how particle shape can be manipulated to design drug carriers to evade macrophages, or alternatively to target macrophages.

Abstract 4217: Contrasting mouse mammary cancer stem cells before and after EMT

We isolated mouse mammary cancer stem cells from a Wnt1-driven tumor model of aggressive breast cancer. These tumorigenic progenitor cells show expression of marker of both luminal (keratin 8) and myoepithelial (keratin 14) cells, express CD24, CD29 and CD49f surface markers. The K8+, K14+ double positive cells can be greatly enriched from less than 5% of the tumor to greater than 60% of the cultured cells in a 3D-culture system under hypoxic conditions. Transplantation of these cultured cells generated tumors with the differentiated morphology of the tumor of origin from a few as a single cell. In a 2D culture setting under normoxic conditions, double positive cells generate single positive differentiated derivates. Serial transplantation of the tumor generated from the cultured cells resulted in increasing growth rate reflected by reduced generation time from 52 days to 21 days after four passages. The fast-growing tumors were strongly positive for vimentin, negative for K14 and few cells expressed K8. Analysis of the cells in 2D revealed a fibroblast-like growth pattern. When grown in 3D, the cells do not form spheroids but rather grow in an invasive pattern in Matrigel. This tumor line has undergone an epithelial to mesenchymal transition (EMT). These cells also generate tumors from single cell transplants but do not generate heterogeneous tumors.

In summary, we have succeeded in cultivating a mammary cancer stem cell, demonstrated its self renewal capacity and potential for differentiation both in vivo and in culture. Furthermore, we have isolated an EMT derivative that is tumorgenic but appears to have lost the potential for self limiting differentiation. This demonstrates that tumorigenic cells with severely restricted capacity for differentiation can be derived from a cancer stem cell. Potential therapies based on the potential of cancer stem cells to differentiate may need to be applied at very early stages of the development of breast cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4217.

SWAP-70-like adapter of T cells, an adapter protein that regulates early TCR-initiated signaling in Th2 lineage cells

We describe the isolation of a protein, SWAP-70-like adapter of T cells (SLAT), which is expressed at high levels in thymocytes and differentiated Th2 cells. SLAT expression was upregulated in differentiating Th2 cells and downregulated in Th1 cells. Ectopic SLAT expression exerted positive or negative effects on IL-4 versus IFNgamma induction, respectively. TCR signaling induced translocation of SLAT to the immunological synapse and its association with ZAP-70 kinase. SLAT reduced the association of ZAP-70 with TCR-zeta and interfered with ZAP-70 but not Lck signaling. Consistent with these results, pharmacological inhibition of ZAP-70 also induced Th2 skewing. Thus, SLAT is a protein which plays a role in Th2 development and/or activation, perhaps by interfering with ZAP-70 signaling.

Translocation of PKC[theta] in T cells is mediated by a nonconventional, PI3-K- and Vav-dependent pathway, but does not absolutely require phospholipase C

PKCtheta plays an essential role in activation of mature T cells via stimulation of AP-1 and NF-kappaB, and is known to selectively translocate to the immunological synapse in antigen-stimulated T cells. Recently, we reported that a Vav/Rac pathway which depends on actin cytoskeleton reorganization mediates selective recruitment of PKCtheta to the membrane or cytoskeleton and its catalytic activation by anti-CD3/CD28 costimulation. Because this pathway acted selectively on PKCtheta, we addressed here the question of whether the translocation and activation of PKCtheta in T cells is regulated by a unique pathway distinct from the conventional mechanism for PKC activation, i.e., PLC-mediated production of DAG. Using three independent approaches, i.e., a selective PLC inhibitor, a PLCgamma1-deficient T cell line, or a dominant negative PLCgamma1 mutant, we demonstrate that CD3/CD28-induced membrane recruitment and COOH-terminal phosphorylation of PKCtheta are largely independent of PLC. In contrast, the same inhibitory strategies blocked the membrane translocation of PKCalpha. Membrane or lipid raft recruitment of PKCtheta (but not PKCalpha) was absent in T cells treated with phosphatidylinositol 3-kinase (PI3-K) inhibitors or in Vav-deficient T cells, and was enhanced by constitutively active PI3-K. 3-phosphoinositide-dependent kinase-1 (PDK1) also upregulated the membrane translocation of PKCtheta;, but did not associate with it. These results provide evidence that a nonconventional PI3-K- and Vav-dependent pathway mediates the selective membrane recruitment and, possibly, activation of PKCtheta in T cells.

Dysregulation of T lymphocyte function in itchy mice: a role for Itch in TH2 differentiation

Itch is an E3 ubiquitin ligase that is disrupted in nonagouti-lethal or itchy mice. Itch deficiency leads to severe immune and inflammatory disorders and constant itching of the skin. Here we show that Itchminus sign/minus sign T cells show an activated phenotype and enhanced proliferation. Production of the type 2 T helper (TH2) cell cytokines interleukin 4 (IL-4) and IL-5 by Itchminus sign/minus sign T cells was augmented upon stimulation, and the TH2-dependent serum concentrations of immunoglobulin G1 (IgG1) and IgE in itchy mice were also increased. Molecularly, Itch associated with and induced ubiquitination of JunB, a transcription factor that is involved in TH2 differentiation. These results provide a molecular link between Itch deficiency and the aberrant activation of immune responses in itchy mice.

Cbl promotes ubiquitination of the T cell receptor zeta through an adaptor function of Zap-70

Triggering of the T cell antigen receptor (TCR).CD3 complex induces its ubiquitination. However, the molecular events that lead to ubiquitin conjugation to these cell surface molecules have not been defined. Here we report that Cbl, a RING-type E3 ubiquitin-protein ligase, promotes ubiquitination of TCR zeta chain, which requires its functional variant Src homology 2 domain and an intact RING finger. The tyrosine kinase Zap-70, which binds to both TCR zeta and Cbl, plays an adaptor role in these events. Mutations in TCR zeta, Zap-70, or Cbl that disrupt the interaction between TCR zeta and Zap-70 or between Zap-70 and Cbl reduce ubiquitination of TCR zeta. Our results suggest a novel mechanism by which Cbl negatively regulates T cell development and activation by inducing ubiquitination of the TCR.CD3 components.

Interrelationship between insulin, leptin and growth hormone in growth hormone-treated children

OBJECTIVES

The aim of the study was to examine insulin homeostasis during growth hormone (GH) therapy, and to investigate the effect of GH treatment on insulin and leptin concentration in obese children.

SUBJECTS

Nineteen obese children (8 with Prader-Willi Syndrome (PWS)) were treated with GH 0.1 IU/kg/day dose for 3 months and were compared with 29 non-treated age and sex matched obese children (9 PWS) and 49 GH treated non-obese short children. Mean age of the children was 10.3+/-1.8 (6.7-13.8) y, with body mass index of 23.6+/-10.4 (11.5-47) kg/m2.

RESULTS

Leptin concentration decreased and was correlated inversely with initial leptin value (r2=-0.374, P<0.001) and decreased body mass (r2=0.338, P=0.001). Insulin sensitivity index was not significantly changed during therapy. Leptin decrease after 3 months of GH administration was correlated inversely with the increase in first phase insulin response to intravenous glucose tolerance test (IVGTT) (r2=-0.595, P<0.001). Results of long-term follow-up of treated patients demonstrated a decrease in insulin concentration after cessation of therapy. In GH-treated subjects, the glucose increase in response to glucose load appeared to be higher than in untreated subjects.

CONCLUSION

The high insulin response to glucose load seen in GH-treated subjects was appropriate to their glucose concentration and the insulin sensitivity index was unchanged relative to the pretreatment period. Increased insulin dosage in our patients did not induce an increase in leptin concentrations as had been hypothesised.

Cbl-b, a RING-type E3 ubiquitin ligase, targets phosphatidylinositol 3-kinase for ubiquitination in T cells

Cbl-b is implicated in setting the threshold of T lymphocyte activation. In Cbl-b-deficient T cells, the activation of Vav, a guanine nucleotide exchange factor, is significantly enhanced. The molecular mechanism underlying Cbl-b-regulated Vav activation was unclear. Here it is shown that Cbl-b interacts with and induces ubiquitin conjugation to the p85 regulatory subunit of phosphatidylinositol 3-kinase, an upstream regulator of Vav. A functional RING finger of Cbl-b was essential for p85 ubiquitination. However, a loss of function mutation at the well-conserved amino-terminal variant src homology (SH) 2 domain of Cbl-b did not affect its ligase activity. A distal carboxyl-terminal proline-rich region in Cbl-b was mapped to contain the primary binding sequences for the SH3 domain of p85. Deletion of either the distal proline-rich region in Cbl-b or the SH3 domain of p85 severely reduced ubiquitin conjugation to p85. The data suggest a molecular link for Cbl-b-mediated negative regulation of Vav, with phosphatidylinositol 3-kinase as a direct target for Cbl-b E3 ubiquitin ligase.

Recognition and ubiquitination of Notch by Itch, a hect-type E3 ubiquitin ligase

Genetic studies identified Itch, which is a homologous to the E6-associated protein carboxyl terminus (Hect) domain-containing E3 ubiquitin-protein ligase that is disrupted in non-agouti lethal mice or Itchy mice. Itch-deficiency results in abnormal immune responses and constant itching in the skin. Here, Itch was shown to associate with Notch, a protein involved in cell fate decision in many mammalian cell types, including cells in the immune system. Itch binds to the N-terminal portion of the Notch intracellular domain via its WW domains and promotes ubiquitination of Notch through its Hect ubiquitin ligase domain. Thus, Itch may participate in the regulation of immune responses by modifying Notch-mediated signaling.

Specific in vitro proliferative immune responses and lymphokine production in Ethiopian children with and without tuberculosis

We investigated the profile of some in vitro parameters of cellular immune responses in non-HIV-infected Ethiopian children and young adults with and without tuberculosis (TB) as compared to healthy Ethiopian and non-Ethiopian controls. The in vitro proliferative responses of peripheral blood mononuclear cells (PBMC) to purified protein derivative (PPD) were determined in 15 Ethiopian children and young adults with TB, 12 healthy Ethiopian children who were contacts of TB patients, 20 Ethiopian children without contact with TB and ten non-Ethiopian controls. All TB patients and contacts had a positive Mantoux skin test. The PBMC proliferative response to PPD of the Ethiopian children with TB was significantly higher than that of the Ethiopian children without TB, while all Ethiopian children demonstrated stronger proliferative response as compared to non-Ethiopian healthy controls. Interleukin 2 (IL-2), interferon gamma (IFN-gamma), interleukin 4 (IL-4) and interleukin 6 (IL-6) were measured by ELISA assays performed on the supernatant of PPD-stimulated and non-stimulated PBMC cultures of seven Ethiopian children with TB, ten Ethiopian children without TB and eight non-Ethiopian controls. IFN-gamma and IL-4 were undetectable and IL-2 levels in unstimulated supernatants were low in all groups. PPD stimulation induced a significant rise in IL-2 levels in Ethiopians with TB as compared to all other groups. There was no increase above baseline in IL-6 levels in any group studied.

CONCLUSIONS

Ethiopian children with TB exhibit a strong cellular immune response as expressed by Mantoux tests and lack of stimulation of IL-4 and IL-6 production. This pattern suggests a Th1 type effective cellular immune response to mycobacteria in a cohort of young Ethiopians with TB.

Sertoli cell tumor causing precocious puberty in a girl with Peutz-Jeghers syndrome

Distinctive ovarian and cervical tumors are associated with Peutz-Jeghers syndrome (PJS). The most common gynecological tumors in this syndrome are adenoma malignum of the uterine cervix and ovarian sex cord tumor, particularly sex cord tumor with annular tubules (SCTAT). Other kinds of ovarian tumors have been rarely reported in association of PJS, including Sertoli cell tumors. We report a case of a 4.5-year-old girl with PJS who presented with isosexual precocious puberty (IPP) due to ovarian lipid-rich Sertoli cell tumor. In addition to estrinizing effect of the tumor, the patient had decidual reaction secondary to tumor-derived progesterone secretion. The literature on gonadal tumors in PJS is reviewed, including one previous report of ovarian lipid-rich Sertoli cell tumor associated with this syndrome.

Extracorporeal losses of insulin-like growth factor-I and insulin-like growth factor binding protein-3 in adult patients on CAPD

The effects of extracorporeal (urinary plus peritoneal) losses of insulin-like growth factor I (IGF-I) and insulin-like growth factor binding protein-3 (IGFBP-3) on their respective serum levels were studied in 10 adult patients (aged 42-74 years) with end-stage renal failure and residual renal function of 0-4.5 mL/min. All patients had been on continuous ambulatory peritoneal dialysis (CAPD) for a period of 2-27 months. Morning serum, 24-hour urine, and 8-hour overnight peritoneal concentrations of IGF-I and IGFBP-3 were measured by radioimmuno- (Incstar) and immunoradiometric (Active) assays. CAPD patients showed extracorporeal losses (mean +/- SEM) of 118.7 +/- 10.6 micrograms (urinary 6.4 +/- 2.8 and peritoneal 112.3 +/- 8.5 micrograms) of IGF-I/24 hour and 1.5 +/- 0.1 mg (urinary 0.2 +/- 0.1 mg and peritoneal 1.3 +/- 0.1 mg) of IGFBP-3/24 hour. Extracorporeal losses of IGF-I accounted for about 4% of the daily production rate of this polypeptide, and the peritoneal and urinary concentrations of IGFBP-3 did not exceed 4% and 14%, respectively, of their serum levels. Serum concentrations of IGF-I (227.7 +/- 64.2 micrograms/L) and IGFBP-3 (5.3 +/- 2.4 mg/L) were not significantly correlated with extracorporeal, peritoneal, or urinary losses of these proteins or with residual renal function. We suggest that extracorporeal losses of IGF-I and IGFBP-3 in adult patients on CAPD do not influence their serum levels and that IGF-I may therefore be used as a marker of malnutrition.

Vitamin A levels and growth hormone axis

Vitamin A (VA) is required for normal growth and development retinoic acid may be the active metabolite through binding to nuclear receptors. Recently a correlation between nocturnal growth hormone (GH) secretion and VA was was found in short slowly growing children. We determined the 24-hour integrated concentration of GH (IC-GH), GH response to provocative stimuli, IGF-I, IGF-binding protein-3 (IGF-BP3) and GH-binding protein (GH-BP) in 34 prepubertal children (25 m/9 f) 5-10 years of age, height -2.5 to 1.5 SDS and body mass index -1.5 to 1.5 SDS for age and sex. Since folic acid, vitamin B12, IGF-I, cholesterol, triglycerides and VA carrier proteins were normal we assumed that no major nutritional deficiency existed. The correlation matrix of the variates tested were p < 0.05 for VA and IC-GH and p < 0.006 for IGF-BP3. It is suggested that VA might have a direct affect on both ICGH and IGF-BP3.

Effect of timing of growth hormone administration on plasma growth-hormone-binding activity, insulin-like growth factor-I and growth in children with a subnormal spontaneous secretion of growth hormone

Since normal pulsatile growth-hormone (GH) secretion displays a major and consistent surge during sleep, we studied the effect of timing of GH supplementation on plasma GH-binding protein activity (GH-BP), insulin-like growth factor-I (IGF-I) and growth. 34 prepubertal subjects (28 boys, 6 girls) aged 8-11 years, of short stature (< 2 SD for age), with a GH response to provocative test > 10 micrograms/l and a subnormal 24-hour GH secretion (< 3 micrograms/l), were randomly allocated to receive Bio-Tropin (recombinant GH, Bio-Technology, Israel) 0.81 IU/kg/week in 3 equally divided doses. GH was administered either at 8.00-10.00 h (M group), 14.00-16.00 h (AN group) or 19.00-21.00 h (NT group). Height velocity, IGF-I and GH-BP were determined prior to and after 6 and 12 months on GH therapy in the three groups. There was no significant difference between the three groups in the growth response, IGF-I and GH-BP increase, all of which increased significantly during GH therapy. Although GH levels after the injection decline to preinjection levels after 10 h, the changes induced by GH therapy, as reflected in IGF-I and GH-BP, last in the circulation long enough to prevent fluctuations in its action. The similarity of IGF-I and of GH-BP levels in the three treatment groups might explain the similar growth effects of the 3 protocols.

The effect of exogenous and endogenous growth hormone on plasma growth hormone binding activity in prepubertal children

To investigate the relationship between plasma growth hormone (GH) and plasma GH-binding protein (GHBP) activity we studied the effects of exogenous and endogenous GH on GHBP in children with a normal response to GH stimulation. The effect of exogenous GH on plasma binding activity was studied for 12 h after the administration of a subcutaneous GH bolus of 0.1 IU/kg and during the first year of GH therapy. The effect of endogenous GH secretion on GHBP was studied by measuring the integrated concentration (IC) of GH and GHBP over 24 h by means of a continuous blood withdrawal procedure. We also measured the GH and GHBP response to GH provocative tests. One hundred and two prepubertal children, 69 males, 33 females, age 8.8 +/- 2.2 years (mean +/- SD), were studied. Eighty-one were short, < 2 SDS for age and gender, and 21 were of normal height for age and gender. There was no difference in IC-GHBP between boys and girls. It correlated positively with age and body mass index (r = 0.802, p < 0.001 and r = 0.340, p < 0.001, respectively) but correlated negatively with ICGH (r = -0.412, p < 0.001) and with height velocity standard deviation scores (SDS, r = -0.355, p = 0.001). No correlation of ICGHBP with maximal GH response to provocative tests, insulin-like growth factor 1 levels, height in SDS or growth velocity after 1 year of GH therapy was found. During a provocative test there is an abrupt increase in GH but not change in GHBP.(ABSTRACT TRUNCATED AT 250 WORDS)

Assessment of growth hormone (GH) axis in Turner's syndrome using 24-hour integrated concentrations of GH, insulin-like growth factor-I, plasma GH-binding activity, GH binding to IM9 cells, and GH response to pharmacological stimulation

The GH axis was studied in Turner's syndrome (TS) patients. Thirty-seven prepubertal TS patients and 42 normally growing girls (NGG; 5.5-16.3 yr old), of whom 13 were prepubertal, were studied by 24-h continuous blood withdrawal and provocative tests. The 24-h integrated concentrations of GH (IC-GH), FSH (IC-FSH), and insulin-like growth factor-I (IC-IGF-I) as well as the IC-IGF-I/IC-GH ratio were determined. An increase in IC-GH with age and progression of puberty was found in NGG, but not in TS. IC-GH in the NGG was significantly higher than that in age-matched TS patients. Estrogen replacement therapy normalized IC-GH levels in 6 TS patients in whom these levels were subnormal for age. A positive correlation between IC-GH and IC-FSH or IC-estradiol was found in NGG (r = 0.462; P less than 0.01), but not in TS patients. The IC-IGF-I/IC-GH ratio was significantly higher in the TS than in the NGG group. Serum GH-binding activity and serum GH binding to IM9 cells in the TS group did not differ from those in the normal group. We hypothesize that the growth retardation of TS results from a combination of insufficient GH secretion, mainly due to sex steroid deficiency, and an end-organ resistance to IGF-I. IGF-I receptor studies are needed to test this speculation about IGF-I resistance.

Activated interferon system in healthy homosexual men

More than 50% of a group of healthy homosexuals in Israel were found to have an activated interferon (IFN) system as evidenced by markedly elevated blood IFN levels, increased in vitro production of IFN by unstimulated peripheral blood mononuclear cells and HuIFN-alpha and HuIFN-gamma production by appropriately stimulated cells, and a surprisingly high incidence of an antiviral state of cells. This pattern resembles that found in persons with acute viral illness, and is unlike that found in normal healthy controls. The type of IFN in the blood was found to be unusual in that it was mainly HuIFN-alpha, pH 2-labile, a type of IFN found in certain collagen diseases as well as in homosexual men suffering from Kaposi's sarcoma or lymphadenopathy. Natural killer (NK) cytotoxic activity was found to be somewhat lower than that found in normal controls, although no correlation was found between blood IFN levels and NK activity. Mean (2'-5')-oligoisoadenylate synthetase levels in cell extracts were intermediate between normal controls and patients with viral illness. Likewise no correlation was found between enzyme levels and blood IFN levels. The highly activated IFN system found in certain homosexuals, as well as the increased spontaneous production of IFN by unstimulated mononuclear cells, suggest the possibility of the presence of a virus, active or latent, in these individuals. This virus could be a retrovirus such as HTLV-III or LAV which have recently been isolated from AIDS patients. The special type of IFN present could be the response to a novel virus in an unusual situation. On the basis of recent reports, we speculate that homosexuals with highly activated IFN systems who produce pH 2-labile HuIFN-alpha could be at increased risk for developing AIDS.

Suppressor T-cell activity in newborns and mothers

We studied autologous and allogeneic concanavalin A (Con A)-induced suppression of proliferative responses to phytohemagglutinin (PHA) and Con A in peripheral blood mononuclear cells in 24 normal newborns and compared the results with those obtained from 20 normal older children. Three concentrations of PHA and one of Con A were used to stimulate responder cells. Suppressor activity, elicited in the stimulated cell population after 48 h pre-incubation with Con A, was expressed as percentage inhibition of the proliferative response to PHA. There was an inverse relationship between PHA concentration and suppressor activity, and autologous suppression was greater than allogeneic suppression within each group of patients and at each mitogen concentration. In both the autologous and allogeneic systems, older children showed more suppressor activity than newborns. Feto-maternal pairing showed that newborns efficiently suppress their mother's mitogenic responses, but the mothers do not suppress their own or other newborn's lymphocytes, despite having normal autologous suppressor capability. We suggest that suppressor activity by the fetus and it's inhibition in the mother may play a part in the mechanism for controlling maternal-fetal immune rejection.

Effect of colchicine on immunoregulatory abnormalities in familial Mediterranean fever

The effect of colchicine on immunoregulatory T lymphocytes in children with familial Mediterranean fever (FMF) was studied. Concanavalin A (Con A)-induced suppressor cell function was significantly (P less than 0.0001) decreased in five untreated FMF patients (15 +/- 3%, mean +/- s.e.) as compared to six age matched paediatric controls (46 +/- 3%) and eight healthy adults (49 +/- 4%). When the five untreated FMF patients' mononuclear cells were pre-incubated in vitro with Con A plus 10(-5) M colchicine, their suppressor cell function was significantly increased (52 +/- 10%, P less than 0.01). Similarly, oral colchicine treatment (0.5 mg twice daily) significantly (P = 0.02) increased the five FMF patients' Con A-induced suppressor cell function to levels (34 +/- 6%) that were not significantly (P greater than 0.05) different than the paediatric controls or the healthy adults. The percentage of OKT8+ cells (but not OKT3+ or OKT4+ cells) was significantly (P less than 0.0001) decreased in 10 untreated FMF patients (16.0 +/- 0.9) as compared to 10 paediatric controls (27.6 +/- 2) or 10 healthy adults (25.7 +/- 0.6). The 10 untreated FMF patients had a significant (P less than 0.002) increase in the OKT4/OKT8 ratio (2.41 +/- 0.13) as compared to 10 FMF patients treated with 0.5 mg twice daily of colchicine (1.81 +/- 0.08), 10 pediatric controls (1.47 +/- 0.2), or 10 healthy adults (1.78 +/- 0.11). Colchicine appears to have corrected the FMF patients' elevated OKT4/OKT8 ratio by both decreasing the percentage of OKT4+ cells and increasing (but only partially correcting) the percentage of OKT8+ cells. Thus FMF patients have a suppressor cell deficiency in which colchicine treatment corrects their deficiency of Con A-induced suppressor cell function and their elevated OKT4/OKT8 ratio. This raises the possibility that colchicine might be potentially useful as an immunomodulating drug in treating patients with autoimmune or allergic diseases associated with a suppressor cell deficiency.

Cellular immunity in children with coeliac disease

The experimental evidence implicating defective cell-mediated immunity in coeliac disease, a condition where symptomatology is believed to be due to immunological reaction to wheat gluten, is often inconsistent and sometimes controversial. Studies of certain parameters of cellular immunity in four groups of pediatric patients were performed: coeliac patients on normal diet; coeliac patients consuming gluten-free diet; children with cow's milk sensitivity. In all these assays no significant differences were found between treated or untreated coeliac children, infants with milk allergy or the gastro-intestinal control groups. On the basis of this study we could find no evidence of impairment of cell-mediated immunity in coeliac children. This conclusion is compatible with the hypothesis that intestinal damage may be due to a subpopulation of lymphocytes sensitive to gluten in persons with normal immune systems. In adults where abnormalities of cell-mediated immunity have sometimes been noted, the reason could be a loss of lymphocytes from the damaged mucosa of the gastrointestinal tract following prolonged antigenic stimulation. This indicated the need for strict adherence to a gluten-free-diet.

Effect of thymic humoral factor on cellular immune factors of normal children and of pediatric patients with ataxia telangiectasia and Down's syndrome

Cellular immune functions of nine Down's syndrome patients and of nine was Ataxia telangiectasia vs. nine normal children and nine cord bloods, were evaluated using in vitro assays of peripheral blood lymphocytes. The in vitro assays included E rosette formation, antilymphocytic cytotoxicity by an antithymic antiserum and leukocyte migration inhibition factor (LIF) production. The mitogens and antigens used were phytohemagglutinin, purified protein derivative, and monilia antigen. The effect of a thymic hormone (THF) on these parameters was evaluated and it was administered therapeutically to three Down's syndrome patients and to two patients with Ataxia telangiectasia. Most deficient T-cell functions were reversed to normal after incubation of the lymphocytes with THF, or after THF therapeutic administration. In two Down's syndrome cases, the clinical course was not altered by THF administration, while one seemed to benefit from it markedly. One of the Atactic patients recovered from a severe viral infection, while the other died from intractable bronchopneumonia.

Thymic deficiency in Down's syndrome

Children with Down's syndrome (DS) often have small and abnormal thymuses, with lymphocyte depletion, diminution of the cortex, and loss of corticomedullary demarcation--a picture resembling thymic involution. Besides this, they have markedly enlarged Hassall's corpuscles, some surrounded by a sheath of lymphocytes. Patients with DS are known to have increased numbers of respiratory infections; they also have a higher incidence of lymphatic leukemia than do individuals who do not have DS. Studies of cell-mediated (thymic-dependent) immunity demonstrate that children with DS have both diminished numbers of T cells as well as functional deficiency of these cells.

Immune deficiency of T system with possible T cell regulatory activity defect

The occurrence of T system immunodeficiency in an infant together with excessive production of IgM and, to a lesser degree, of IgG and IgA, is an unusual combination. A case is reported in which an unremitting lung infection with lymphadenopathy and hepatosplenomegaly developed in a previously healthy two-month-old infant. Leukocytosis with lymphocytosis, monocytosis and eosinophilia was rapidly followed by leukopenia and lymphocytepenia after a blood transfusion for anemia. There was a transient clinical remission, but on relapse 10 days later, quantitative and functional T cell deficiency was found together with increased IgG and IgA and with IgM values reaching 50 times greater than normal. Thymic humoral factor was successful in vitro in increasing the number of identifiable T cells (E rosetts) as well as T cell function (leukocyte migration inhibition factor production). However, the infant died suddenly, and at autopsy evidence of a generalized inflammatory reaction compatible with a viral infection was found. The thymus was small, hypoplastic and hypocellular. It is speculated that the T system deficiency may have been acquired following Epstein-Barr virus infection, and that T cell regulatory activity of immunoglobulin production was defective.

Cellular immunity in newborn infants and children: stimulation of lymphocyte protein synthesis as a measure of immune competence

An assay based on the early stimulation of protein synthesis in lymphocytes has been used as an in vitro measure of cellular immune competence. 3H-labelled leucine incorporation into human peripheral lymphocytes (PBL) stimulated by the mitogens phytohaemagglutinin (PHA), wax bean agglutinin (WBA) and Concanavalin A (Con A) was measured after one day in culture. This assay offers a technical advantage over the analogous 3H-labelled thymidine incorporation assay, because of the short incubation time required and the absence of homologous serum in the assay system. Newborn infants and patients with Down's syndrome as a group had normal responses, whereas those suffering from recurrent infections demonstrated normal or hyper-reactive responses. Patients with lymphoproliferative disorders, ataxia telangiectasia, and some patients under steroid therapy had diminished immune proliferative reactions. These results are in agreement with most previously reported studies using other assay systems.