Longitudinal Associations Between Physical Health Conditions in Childhood and Attention-Deficit/Hyperactivity Disorder Symptoms at Age 17 Years

OBJECTIVE

Although evidence suggests significant cross-sectional relationships between attention-deficit/hyperactivity disorder (ADHD) and several physical health conditions, less is known about their longitudinal associations. We investigated the cumulative effect of childhood physical health conditions on ADHD symptoms at age 17 years, controlling for environmental factors, ADHD medication status, and ADHD symptoms at age 3 years.

METHOD

Using Millennium Cohort Study data (weighted n = 8,059), we assessed whether 4 physical health clusters (sensory, neurological, atopic, and cardio-metabolic) were associated with scores on the ADHD subscale from the Strengths and Difficulties Questionnaire at age 17 years. Environmental factors were grouped into 5 cumulative risk indices: prenatal, perinatal, postnatal environment, postnatal maternal well-being, and sociodemographic factors. Regression analyses determined whether each physical health cluster was associated with ADHD score while controlling for environmental factors, ADHD medication, and earlier symptoms.

RESULTS

Sensory, neurological, and cardio-metabolic clusters were all significantly associated with ADHD symptoms (β range = 0.04-0.09, p < .001). The overall model explained 2% of the variance. This rose to 21% (ΔR2 = 0.06) after adjusting for confounders. The sensory (β = 0.06) and neurological (β = 0.06) clusters remained significant (R2 = 0.21, ΔR2 = 0.06), but the cardio-metabolic cluster was no longer a significant predictor.

CONCLUSION

Sensory or neurological conditions in childhood were associated with higher ADHD symptoms aged 17 after adjustment of confounders. This was not the case for atopic or cardio-metabolic conditions. These findings have implications for the care of children with sensory/neurological conditions and future research examining ADHD etiopathophysiology.

Engineered Fc-glycosylation switch to eliminate antibody effector function

Antibodies mediate effector functions through Fcγ receptor (FcγR) interactions and complement activation, causing cytokine release, degranulation, phagocytosis, and cell death. They are often undesired for development of therapeutic antibodies where only antigen binding or neutralization would be ideal. Effector elimination has been successful with extensive mutagenesis, but these approaches can potentially lead to manufacturability and immunogenicity issues. By switching the native glycosylation site from position 297 to 298, we created alternative antibody glycosylation variants in the receptor interaction interface as a novel strategy to eliminate the effector functions. The engineered glycosylation site at Asn298 was confirmed by SDS-PAGE, mass spectrometry, and X-ray crystallography (PDB code 6X3I). The lead NNAS mutant (S298N/T299A/Y300S) shows no detectable binding to mouse or human FcγRs by surface plasmon resonance analyses. The effector functions of the mutant are completely eliminated when measured in antibody-dependent cell-meditated cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC) assays. In vivo, the NNAS mutant made on an antibody against a human lymphocyte antigen does not deplete T cells or B cells in transgenic mice, in contrast to wild-type antibody. Structural study confirms the successful glycosylation switch to the engineered Asn298 site. The engineered glycosylation would clash with approaching FcγRs based on reported Fc-FcγR co-crystal structures. In addition, the NNAS mutants of multiple antibodies retain binding to antigens and neonatal Fc receptor, exhibit comparable purification yields and thermal stability, and display normal circulation half-life in mice and non-human primate. Our work provides a novel approach for generating therapeutic antibodies devoid of any ADCC and CDC activities with potentially lower immunogenicity.

Atrial fibrillation substrate mapping with decrement evoked potential mapping

Funding Acknowledgements

Type of funding sources: Foundation. Main funding source(s): Sociedad Española de Cardiologia.

OnBehalf

DEFINE-AF

Background

Identifying and targeting atrial substrate zones that are vulnerable to unidirectional block and slow conduction may be critical to improve the outcomes of atrial fibrillation (AF) ablation. Functional mapping of the atrial substrate with Decrement Evoked Potential (DeEP) and a single extrastimulus in this population could potentially lead to novel therapeutic strategies.

Aim

1) To systematically analyze whether the DEEP are present in the atrial tissue and their locations after pulmonary vein isolation. 2) To assess their relationship with the underlying voltage.  3) To assess the presence of DEEP as a function of the subtype of AF.

Methods

Consecutive patients with AF undergoing ablation were prospectively enrolled at 3 institutions. A biatrial voltage map was created and after pulmonary vein isolation (PVI). A drive train and an extrastimulus (atrial refractory period + 20ms) was delivered from an epicardial site (proximal CS) and an endocardial site (left atrial appendage (LAA). A multipolar mapping catheter was sequentially placed at 8 left atrial sites and 5 right atrial sites. Electrograms (EGMs) that showed a local delay of &gt;10ms in activation with the extrastimulus were identified as DEEPs. Patients were followed for a mean of 11 ± 5 months

Results

74 patients, 63 pers AF (85%), mean age 62 ± 8, mean LA size 41 ±12 mm were enrolled. Of 19240 EGMs analyzed, 8.2% showed DEEPs (54.6% with CS pacing and 45.4% with LAA pacing, p = 0.0001). The mean local decrement seen was 39 ms. Most DEEPs (76.2%) were identified in sites with a normal EGM at baseline with preserved voltages. DEEPs were differentially distributed within the regions mapped, more frequently in LA than RA (9.2% vs 6.6%, p &lt; 0.0001). Patients with persistent AF had a higher proportion of DEEPs than patients with paroxysmal AF (9.7% vs 5.1%, p &lt; 0.001).

Conclusions

Atrial DEEPs are: 1) More often identified when pacing endocardially. 2) More common in patients with persistent AF. 3) More frequent in the LA than in the RA. 4) Mostly located in regions with normal voltages at baseline. All those findings suggest the importance of the functional substrate mapping in the atrium and could lead to novel therapeutic targets. Abstract Figure. Example of atrial DEEP

P2707Invasive coronary physiology during primary percutaneous coronary intervention in patients treated with intracoronary alteplase or placebo: the double-blind T-TIME physiology substudy

Background

Impaired microcirculatory reperfusion worsens prognosis post-primary percutaneous coronary intervention (PCI) for ST-elevation myocardial infarction (STEMI). Intracoronary (IC) alteplase targets persisting thrombus post-reperfusion & distal embolisation. In the T-TIME trial microvascular obstruction on cardiac magnetic resonance (CMR) did not differ with IC alteplase vs placebo.

Purpose

To prospectively determine if index of microcirculatory resistance (IMR) is lower & coronary flow reserve (CFR) or resistive reserve ratio (RRR) are higher (improved) with IC alteplase, & to provide mechanistic insights.

Methods

A pre-planned substudy of the main protocol. From 2016–2017, STEMI patients from 3 UK hospitals ≤6 hrs ischaemic time were randomised in a 1:1:1 dose-ranging, double-blind design. Following standard care reperfusion, alteplase (10 or 20mg) or placebo was infused over 5–10 mins proximal to the culprit lesion pre-stenting. IMR (primary outcome), CFR & RRR (secondary outcomes) were measured in the culprit artery post-PCI. Physiology results were obscured from clinicians acquiring the data, to maintain blinding. CMR was performed 2 days & 3 months post-STEMI. Subgroup analyses were prespecified including by ischaemic time (<2 hours, 2–4 hrs, >4 hrs) & IMR threshold >32.

Results

In 144 patients (mean age 59 yrs, 80% male), IMR, CFR or RRR post-PCI did not differ with alteplase vs placebo (Table). Patients with ischaemic time <2 hrs had a dose related increase in CFR (placebo 1.2 [IQR 1.1–1.7], alteplase 10mg 1.4 [IQR 1.0–1.8], alteplase 20mg 2.0 [IQR 1.8–2.3] p=0.01 for interaction) & RRR (placebo 1.5 [IQR 1.3–1.9], alteplase 10mg 1.6 [1.1–2.2], alteplase 20mg 2.2 [2.0–2.6], p=0.03 for interaction). In subjects with post-PCI IMR>32, % ST-resolution at 60 mins was worse with alteplase 10mg vs placebo (23.1±53.9 vs 50.9±31.5) & in those with IMR≤32% ST-resolution at 60 mins was better with alteplase 20mg vs placebo (68.0±30.7 vs 39.1±43.2), p=0.002 for interaction. The CMR findings in the substudy & overall trial populations were consistent.

Main results Placebo Alteplase 10mg Alteplase 20mg (n=53) (n=41) (n=50) IMR, median (IQR) 33.0 (17.0–57.0) 22.0 (17.0–42.0) 37.0 (20.0–57.8) p=0.15 p=0.78 CFR, median (IQR) 1.3 (1.1–1.8) 1.4 (1.1–1.9) 1.5 (1.1–2.0) p=0.92 p=0.74 RRR, median (IQR) 1.6 (1.3–2.2) 1.6 (1.4–2.6) 1.8 (1.3–2.4) p=0.69 p=0.81 P-values for comparison of alteplase with placebo.

Conclusions

In acute STEMI with ischaemic time ≤6 hrs, IMR, CFR or RRR post-PCI did not differ with alteplase vs placebo. In those with shorter ischaemic times (<2 hrs) CFR & RRR, but not IMR, were improved with alteplase. We observed interactions between alteplase dose, ischaemic time & mechanisms of effect.

Acknowledgement/Funding

Dr Maznyczka is funded by a fellowship from the British Heart Foundation (FS/16/74/32573). T-TIME was funded by grant 12/170/4 from NIHR-EME

P2807Clinical outcomes with cobalt chromium biolimus eluting drug-eluting stents compared with stainless steel biolimus eluting drug-eluting stents in all-comers patients

Aims

Thinner stent struts may improve deliverability, conformability and reduce vessel injury. We report the first clinical outcomes of the thinner strut (84–88um) cobalt chromium biolimus eluting stent from the Biomatrix Alpha registry and compare these with objective performance criteria from the stainless steel BioMatrix Flex arm of the Leaders study.

Methods

A total of 1257 patients were studied: 400 patients from 12 centres receiving ≥1 Biomatrix Alpha stent were prospectively enrolled into the Biomatrix Alpha registry and then underwent a pre-specified comparison with 857 patients who received a Biomatrix Flex stent in the Leaders study. The primary endpoint was major adverse cardiac events (MACE) defined as the composite of cardiac death, myocardial infarction (MI) or clinically driven target vessel revascularization (TVR) at 9 months. Assuming a 9.2% event rate with BioMatrix Flex, a one-sided type I error (α) of 0.05, and a 4% non-inferiority margin, a sample size of 400 in the Biomatrix alpha registry had >80% power to conclude non-inferiority.

Results

Baseline characteristics in the Alpha registry were typical of an all-comers population with a mean age of 64.7±11.3, diabetes 19%, current smoking 21%, dyslipidemia 57%, hypertension 57%, total stent length per lesion 25.49±13.45, mean stents per procedure 1.59±0.88 and overlapping stents in 13.4%. Observed MACE at 9 months with Alpha was 3.94% (upper limit 5.98%) vs. 9.28% MACE rate with Flex stents in Leaders, which met pre-specified criteria for non-inferiority (p<0.001) and on post hoc testing for superiority yielded p<0.001 for Alpha vs Flex. Secondary endpoints with Alpha included clinically-driven TVR 2.6%, all-cause mortality rate 1.51% and definite/probable stent thrombosis 0.25%.

While both Alpha and Leaders enrolled all-comers, Alpha included longer total stent length per lesion (25.49 vs 23.85mm, p<0.001) and more stents per procedure (mean 1.59 vs 1.34; p<0.001) but fewer patients with diabetes (19% vs 26%; p=0.0087), dyslipidemia (57 vs 65%; p=0.0037), prior MI (18.8% vs 32.2%; p<0.001) or acute coronary syndrome (41% vs 55%; p<0.001). To correct for these imbalances and to assess robustness further, a propensity score at the patient level data was undertaken (total sample size of 1257 patients; 400 from the Alpha registry and 857 from the LEADERS study). A propensity score stratification method was used obtaining 5 quintiles for adjusted analysis (each of the 5, containing 251 or 252 patients, 20%). In each of the strata as well as at the aggregate level, a p valve<0.005 was obtained confirming non-inferiority for the primary endpoint.

Conclusion

The thinner strut (84–88um) cobalt chromium Biomatrix Alpha stent demonstrated low MACE rates at 9 months which were non-inferior to MACE outcomes with the stainless steel Biomatrix Flex in the Leaders study. The robustness of this finding was further confirmed by a propensity score analysis.

Acknowledgement/Funding

Biosensors

Application of Bayesian statistics to estimate nitrous oxide emission factors of three nitrogen fertilisers on UK grasslands

Trapezoidal integration by linear interpolation of data points is by far the most commonly used method of cumulative flux calculations of nitrous oxide (N₂O) in studies that use flux chambers; however, this method is incapable of providing accurate uncertainty estimates. A Bayesian approach was used to calculate N₂O emission factors (EFs) and their associated uncertainties from flux chamber measurements made after the application of nitrogen fertilisers, in the form of ammonium nitrate (AN), urea (Ur) and urea treated with Agrotain® urease inhibitor (UI) at four grassland sites in the UK. The comparison between the cumulative fluxes estimated using the Bayesian and linear interpolation methods were broadly similar (R² = 0.79); however, the Bayesian method was capable of providing realistic uncertainties when a limited number of data points is available. The study reports mean EF values (and 95% confidence intervals) of 0.60 ± 0.63, 0.29 ± 0.22 and 0.26 ± 0.17% of applied N emitted as N₂O for the AN, Ur and UI treatments, respectively. There was no significant difference between N₂O emissions from the Ur and UI treatments. In the case of the automatic chamber data collected at one site in this study, the data did not fit the log-normal model, implying that more complex models may be needed, particularly for measurement data with high temporal resolution.

A data mining and item response mixture modeling method to retrospectively measure Diagnostic and Statistical Manual of Mental Disorders-5 attention deficit hyperactivity disorder in the 1970 British Cohort Study

OBJECTIVE

To facilitate future outcome studies, we aimed to develop a robust and replicable method for estimating a categorical and dimensional measure of Diagnostic and Statistical Manual of Mental Disorders-5 (DSM-5) attention deficit hyperactivity disorder (ADHD) in the 1970 British Cohort Study (BCS70).

METHOD

Following a data mining framework, we mapped DSM-5 ADHD symptoms to age 10 BCS70 data (N = 11,426) and derived a 16-item scale (α = 0.85). Mapping was validated by an expert panel. A categorical subgroup was derived (n = 594, 5.2%), and a zero-inflated item response theory (IRT) mixture model fitted to estimate a dimensional measure.

RESULTS

Subgroup composition was comparable with other ADHD samples. Relative risk ratios (ADHD/not ADHD) included boys = 1.38, unemployed fathers = 2.07, below average reading = 2.58, and depressed parent = 3.73. Our estimated measures correlated with two derived reference scales: Strengths and Difficulties Questionnaire hyperactivity (r = 0.74) and a Rutter/Conners-based scale (r = 0.81), supporting construct validity. IRT model items (symptoms) had moderate to high discrimination (0.90-2.81) and provided maximum information at average to moderate theta levels of ADHD (0.5-1.75).

CONCLUSION

We extended previous work to identify ADHD in BCS70, derived scales from existing data, modeled ADHD items with IRT, and adjusted for a zero-inflated distribution. Psychometric properties were promising, and this work will enable future studies of causal mechanisms in ADHD.

Quantitative Proteomic Profiling Reveals Novel Plasmodium falciparum Surface Antigens and Possible Vaccine Candidates

Despite recent efforts toward control and elimination, malaria remains a major public health problem worldwide. Plasmodium falciparum resistance against artemisinin, used in front line combination drugs, is on the rise, and the only approved vaccine shows limited efficacy. Combinations of novel and tailored drug and vaccine interventions are required to maintain the momentum of the current malaria elimination program. Current evidence suggests that strain-transcendent protection against malaria infection can be achieved using whole organism vaccination or with a polyvalent vaccine covering multiple antigens or epitopes. These approaches have been successfully applied to the human-infective sporozoite stage. Both systemic and tissue-specific pathology during infection with the human malaria parasite P. falciparum is caused by asexual blood stages. Tissue tropism and vascular sequestration are the result of specific binding interactions between antigens on the parasite-infected red blood cell (pRBC) surface and endothelial receptors. The major surface antigen and parasite ligand binding to endothelial receptors, PfEMP1 is encoded by about 60 variants per genome and shows high sequence diversity across strains. Apart from PfEMP1 and three additional variant surface antigen families RIFIN, STEVOR, and SURFIN, systematic analysis of the infected red blood cell surface is lacking. Here we present the most comprehensive proteomic investigation of the parasitized red blood cell surface so far. Apart from the known variant surface antigens, we identified a set of putative single copy surface antigens with low sequence diversity, several of which are validated in a series of complementary experiments. Further functional and immunological investigation is underway to test these novel P. falciparum blood stage proteins as possible vaccine candidates.

Idiopathic constriction of the fetal ductus arteriosus

Constriction of the ductus arteriosus in the fetus is well studied, but mostly secondary to maternal exposure to indomethacin or other non-steroidal anti-inflammatory medications, or structural cardiac lesions. We present a case of a fetus presenting with right ventricular hypertrophy secondary to an S-shaped ductus arteriosus with distal constriction diagnosed by pulsed Doppler imaging. A review of the recent English literature of similar cases is presented.

A technical and clinical evaluation of digital X-ray radiogrammetry

Skeletal assessment by morphometry at peripheral sites (e.g. metacarpal index), although simple to perform and widely available, was limited by poor precision and technical aspects of radiogrammetry. Digital X-ray radiogrammetry (DXR) uses the principles of this long-established method but applies more sophisticated methodology to overcome these problems. The aims of this study were to (a) investigate the effects of radiographic technique on bone mineral density (BMD) measurement by DXR, (b) compare DXR to dual-energy X-ray absorptiometry (DXA) and single-energy X-ray absorptiometry (SXA) and (c) determine the applicability of DXR in identifying individuals who most appropriately might be referred for axial DXA. Different radiographers performing the radiograph do not adversely affect precision. Precision, unstandardised (CV%) and standardised (sCV%), is good with both double (DF)- and single (SF)-sided emulsion radiographic film, but better with SF (CV% 0.92 vs 1.12 DF; SCV% 1.76 vs 2.93 DF). Repeat analysis precision was determined on SF (CV% 0.24, sCV% 0.55). A significant ( p<0.001), systematic difference was found between BMD measured from DF and SF (mean difference 0.017 g/cm(2)). The overall percentage difference between the methods was 2.98% (range 0.18-5.78%). Correlations between DXR BMD and DXA were moderately good (r=0.56-0.77, p<0.001); with SXA of the forearm they were excellent (r=0.91, p<0.001). The sensitivity and specificity of DXR for detecting women with osteopaenia or osteoporosis (DXA T-score less than -1; World Health Organisation) was determined at the spine [area under curve (AUC)=0.82, standard error (SE)=0.04], femoral neck (AUC=0.84, SE=0.04) and total hip (AUC=0.84, SE=0.04). Based on femoral neck BMD for detection of osteopaenia, a DXR T-score threshold of -1.05 would be appropriate for detection of patients who might benefit most from axial DXA measurements. The DXR is quick and simple to use, having potential for application in a variety of settings as analysis can be performed in a central unit, with radiographs taken in sites over a wide geographical area. Retrospective analysis may also be performed, e.g. on radiographs taken to monitor rheumatoid arthritis. The technique may also provide a simple, widely available and relatively inexpensive method to assess patients at risk of osteopaenia or osteoporosis, and who most appropriately could be referred for axial DXA. This may be particularly relevant in those who suffer low-trauma fractures and attend accident and emergency or fracture clinics, where investigation for osteoporosis is often overlooked.

Reversible inhibition of cathepsin L-like proteases by 4-mer pseudopeptides

A library of 121 pseudopeptides was designed to develop reversible inhibitors of trypanosomal enzymes (cruzain from Trypanosoma cruzi and congopain from Trypanosoma congolense). The peptides share the framework: Cha-X1-X2-Pro (Cha=cyclohexyl-alanine, X1 and X2 were phenylalanyl analogs), based on a previous report [Lecaille, F., Authié, E., Moreau, T., Serveau, C., Gauthier, F. and Lalmanach, G. (2001) Eur. J. Biochem. 268, 2733-2741]. Five peptides containing a nitro-substituted aromatic residue (Tyr/Phe) and one a 4-chloro-phenylalanine at the X1 position, and 3-(2-naphthyl)-alanine, homocyclohexylalanine or 3-nitro-tyrosine (3-NO(2)-Tyr) at the X2 position, were selected. They inhibited congopain more effectively than cruzain, except Cha-4-NO(2)-Phe-3-NO(2)-Tyr-Pro which bound the two parasitic enzymes similarly. Among this series, Cha-3-NO(2)-Tyr-HoCha-Pro and Cha-4-NO(2)-Phe-3-NO(2)-Tyr-Pro are the most selective for congopain relative to host cathepsins. No hydrolysis occurred upon prolonged incubation time with purified enzymes. In addition introduction of non-proteogenic residues in the peptidyl backbone greatly enhanced resistance to proteolysis by mammalian sera.

Platelet reactivity in acute coronary syndromes: evidence for differences in platelet behaviour between unstable angina and myocardial infarction

Previous work has shown that P-selectin and mean platelet volume, two markers associated with platelet reactivity, are elevated in acute coronary syndromes. This study investigated the possibility that these markers may define unstable angina (UA) and acute myocardial infarction (MI) as two separate conditions based on platelet behaviour. Mean platelet volume (MPV) was higher in UA patients (n = 15) than in those diagnosed with MI (n = 15) (10.7 +/- 0.25 fL, vs. 9.8 +/- 0.27 fL, P = 0.005). Platelet count was lower in UA than in MI (215 +/- 13 x 10(9)/L vs. 271 +/- 20 x 10(9)/L, P = 0.03). The percentage of platelets expressing P-selectin was higher in MI than in UA (9.1 +/- 1.9% vs. 4.2 +/- 0.85%, P = 0.03). This parameter was positively correlated with MPV in UA (r = 0.5, P = 0.04) but negatively correlated in MI (r = -0.6, P = 0.01), with no correlation for ACS as a whole (r = -0.32, P = 0.1). Our results suggest that in MI there is an acute process of generalised platelet activation that is unrelated to changes in MPV, whereas in UA there is an ongoing process of platelet consumption that leads to an increase in platelet size to compensate for a persistent decrease in platelet count. This study suggests that there is a fundamental difference in platelet biology between these two diseases.

RXP 407, a selective inhibitor of the N-domain of angiotensin I-converting enzyme, blocks in vivo the degradation of hemoregulatory peptide acetyl-Ser-Asp-Lys-Pro with no effect on angiotensin I hydrolysis

The phosphinic peptide RXP 407 has recently been identified as the first potent selective inhibitor of the N-active site (domain) of angiotensin-converting enzyme (ACE) in vitro. The aim of this study was to probe the in vivo efficacy of this new ACE inhibitor and to assess its effect on the metabolism of AcSDKP and angiotensin I. In mice infused with increasing doses of RXP 407 (0.1--30 mg/kg/30 min), plasma concentrations of AcSDKP, a physiological substrate of the N-domain, increased significantly and dose dependently toward a plateau 4 to 6 times the basal levels. RXP 407 significantly and dose dependently inhibited ex vivo plasma ACE N-domain activity, whereas it had no inhibitory activity toward the ACE C-domain. RXP 407 (10 mg/kg) did not inhibit the pressor response to an i.v. angiotensin I bolus injection in mice. In contrast, lisinopril infusion (5 and 10 mg/kg/30 min) affected the metabolism of both AcSDKP and angiotensin I. Thus, RXP 407 is the first ACE inhibitor that might be used to control selectively AcSDKP metabolism with no effect on blood pressure regulation.

Potency and selectivity of RXP407 on human, rat, and mouse angiotensin-converting enzyme

By screening phosphinic peptide libraries, we recently reported the discovery of RXP407 (Ac-Asp-PheY(PO2-CH2)LAla-Ala-NH2), a potent N-domain-selective inhibitor of recombinant human angiotensin-converting enzyme (ACE). Preliminary studies to evaluate the in vivo activity of RXP407 in rat led us to suspect possible differences in the binding property of RXP407 between human and rat ACE. The aim of the present study was thus to determine the potency of RXP407 toward rat and mouse ACEs, as compared to non-recombinant human ACE, and to assess the efficacy of this inhibitor in discriminating between the N- and C-domains of these ACE enzymes. By comparing the ability of RXP407 to block purified somatic and germinal ACE from mice, RXP407 was shown to be a potent N-domain-selective inhibitor of mouse somatic ACE, a behavior similar to that observed with human somatic ACE. In contrast, RXP407 appeared less potent toward purified ACE from rat and furthermore was unable to block ACE activity present in crude rat plasma. This study demonstrated that for further evaluation of the in vivo efficacy of RXP407, mice rather than rats should be used as the animal model. Thus, following the change in the Ac-S-D-K-P plasmatic levels, after i.v. injection of RXP407 to mice, will permit the potency and selectivity of this novel ACE inhibitor to be assessed.

Phosphinic peptide inhibitors as tools in the study of the function of zinc metallopeptidases

The development of the combinatorial chemistry of phosphinic peptides has led to the discovery of both highly potent and selective inhibitors of various zinc metalloproteinases. Several properties of these compounds are reviewed, supporting the view that this class of inhibitors should represent useful tools for probing several aspects of the function of this broad family of proteases in vivo.

Parathyroid hormone-related peptide stimulates proliferation of highly tumorigenic human SV40-immortalized breast epithelial cells

Parathyroid hormone-related protein (PTHrP) is the main mediator of humoral hypercalcemia of malignancy (HHM) and it is produced by many tumors, including breast cancers. Breast epithelial cells as well as breast cancer tumors and cell lines have been reported as expressing PTHrP and the PTH/PTHrP receptor, suggesting that PTHrP may act as an autocrine factor influencing proliferation or differentiation of these cell types. We investigated PTHrP gene expression, PTH/PTHrP receptor signaling, and PTHrP-induced mitogenesis in three immortalized human mammary epithelial cell lines that exhibit differential tumorigenicity. The most tumorigenic cells expressed the highest levels of PTHrP messenger RNA (mRNA) and protein. We used reverse-transcription polymerase chain reaction (RT-PCR) and immunoblotting to detect the PTH/PTHrP receptor transcripts and proteins in all of the three cell lines. Treatment with human PTHrP(1-34) [hPTHrP(1-34)] and hPTH(1-34) increased intracellular cyclic adenosine monophosphate (cAMP) but not free Ca2+ in the nontumorigenic line. These agonists increased both cAMP and free Ca2+ levels in the moderately tumorigenic line, but only increased free Ca2+ in the highly tumorigenic line. Application of the PTH/PTHrP receptor antagonist [Asn10,Leu11,D Trp12]PTHrP(7-34) or PTHrP antibodies reduced [3H]thymidine incorporation in a dose-dependent fashion in the highly tumorigenic cell line but did not affect the other lines. Thus, treatment with a PTH/PTHrP receptor antagonist reduced cell proliferation, suggesting that PTHrP signaling mediated by the phospholipase C (PLC) pathway stimulates proliferation of a highly tumorigenic immortalized breast epithelial cell line.

Functional conservation of the active sites of human and Drosophila angiotensin I-converting enzyme

Human somatic angiotensin I-converting enzyme (sACE) has two active sites present in two homologous protein domains, resulting from a tandem gene duplication. It has been proposed that the N- and C-terminal active sites can have specific in vivo roles. In Drosophila melanogaster, Ance and Acercode for two ACE-like single-domain proteins, also predicted to have distinct physiological roles. We have investigated the relationship of Ance and Acer to the N- and C-domains of human sACE by genomic sequence analysis and by using domain-selective inhibitors, including RXP 407, a selective inhibitor of the human N-domain. These phosphinic peptides were potent inhibitors of Acer, but not of Ance. We conclude that the active sites of the N-domain and of Acer share structural features that permit the binding of the unusual RXP407 inhibitor and the hydrolysis of a broader range of peptide structures. In comparison, Ance, like the human C-domain of ACE, displays greater inhibitor selectivity. From the analysis of the published sequence of the Adh region of Drosophila chromosome 2, which carries Ance, Acer, and four additional ACE-like genes, we also suggest that this functional conservation is reflected in an ancestral gene structure identifiable in both protostome and deuterostome lineages and that the duplication seen in vertebrate genomes predates the divergence of these lineages. The conservation of ACE enzymes with distinct active sites in the evolution of both vertebrate and invertebrate species provides further evidence that these two kinds of active sites have different physiological functions.

Isolated extragenital bowenoid papulosis of the neck

We report a case of extragenital bowenoid papulosis (BP) in a healthy immunocompetent 42-year-old man. The lesions occurred on the anterolateral aspects of the neck and were not associated with genital, oral, or periungual lesions. Lesional skin tested positive with the Digene hybrid capture system cocktail assay that identifies infection with a mixture of high to intermediate oncogenic human papillomavirus (HPV) types, including types 16, 18, 31, 33, 35, 45, 51, 52, and 56. This cocktail assay identifies infection with HPV types typically associated with high-grade squamous intraepithelial lesions and invasive carcinoma. This case represents the sixth case of isolated cutaneous BP occurring a significant distance from the genital region.

Short-term growth hormone administration at the time of opportunistic infections in HIV-positive patients

OBJECTIVES

A 12-week course of recombinant human growth hormone is an effective but expensive therapy for established HIV-related wasting. Wasting in HIV disease is often episodic, coinciding with bouts of acute opportunistic infection. We hypothesized that a short course of growth hormone, targeted at the time of opportunistic infection, might improve protein metabolism thereby reducing lean tissue loss.

METHODS

HIV-infected men with acute opportunistic infections, who received standard antimicrobial treatment for their infection as well as intensive nutritional counselling and oral energy supplements, were randomized to receive growth hormone or placebo for 14 days. Principal assessments were protein metabolism (measured by 13C-leucine infusion), body composition (measured by DEXA) and safety.

RESULTS

There were no significant changes in outcome parameters in the placebo group (n = 11). In the growth hormone group (n = 9), protein catabolic rate decreased by 60% in the fasted state (P = 0.02 versus placebo), lean body mass increased by 2.2 kg (P = 0.03 versus baseline) and fat mass decreased by 0.7 kg (P = 0.002 versus baseline). There was no increase in adverse or serious adverse events in the growth hormone as compared with the placebo group.

CONCLUSIONS

A two-week course of growth hormone at the time of acute opportunistic infection in HIV-infected patients improves protein metabolism and body composition during therapy and appears to be safe. This may represent a rational and economical approach to the use of growth hormone therapy.

RXP 407, a phosphinic peptide, is a potent inhibitor of angiotensin I converting enzyme able to differentiate between its two active sites

The human somatic angiotensin converting enzyme (ACE) contains two homologous domains, each bearing a zinc-dependent active site. All of the synthetic inhibitors of this enzyme used in clinical applications interact with these two active sites to a similar extent. Recently, several lines of evidence have suggested that the N-terminal active site of ACE might be involved in specific hydrolysis of some important physiological substrates, like Acetyl-Seryl-Aspartyl-Lysyl-Proline, a negative regulator of hematopoietic stem cell differentiation and proliferation. These findings have stimulated studies aimed at identifying new ACE inhibitors able to block only one of the two active sites of this enzyme. By screening phosphinic peptide libraries, we discovered a phosphinic peptide Ac-Asp-(L)Phepsi(PO2-CH2)(L)Ala-Ala-NH2, called RXP 407, which is able to differentiate the two ACE active sites, with a dissociation constant three orders of magnitude lower for the N-domain of the enzyme. The usefulness of a combinatorial chemistry approach to develop new lead structures is underscored by the unusual chemical structure of RXP 407, as compared with classical ACE inhibitors. As a highly potent and selective inhibitor of the N-terminal active site of wild ACE (Ki = 12 nM), RXP 407, which is metabolically stable in vivo, may lead to a new generation of ACE inhibitors able to block in vivo only a subset of the different functions regulated by ACE.

Activation of the insulin-like growth factor-1 receptor promotes the survival of human keratinocytes following ultraviolet B irradiation

The ultraviolet B (UVB) component of sunlight causes non-melanoma skin cancers due to the damage it inflicts on genomic DNA. The response of epidermal keratinocytes to sunlight depends on the dose of UVB received and the severity of the damage to the DNA. Mild DNA damage typically induces DNA-repair pathways and cell survival, while severe DNA damage provokes apoptosis. Primary human keratinocytes grown in serum-free media respond in a similar manner to UVB irradiation. However, we observed that keratinocytes are exquisitely more susceptible to UVB-induced apoptosis if the growth medium is depleted of exogenous growth factors. Therefore, an exogenous growth factor could provide protection from UVB-induced apoptosis. We found that the only growth factor that provided protection from UVB-induced apoptosis was insulin and that the protective effect elicited by insulin was not due to binding the insulin receptor but, rather, to activation of the insulin-like growth factor-1 (IGF-1) receptor. Additionally, activation of the IGF-1 receptor in combination with UVB irradiation induced keratinocytes to become post-mitotic. This survival function of the IGF-1 receptor in response to UVB irradiation was influenced by activation of phosphatidylinositol-3 kinase and MAP kinase. Prior to UVB irradiation, insulin or IGF-1 had little to no effect on cell growth or viability. Therefore, activation of the IGF-1 receptor in conjunction with UVB irradiation promotes keratinocyte survival at the expense of cell proliferation.

Activation of the insulin-like growth factor-1 receptor promotes the survival of human keratinocytes following ultraviolet B irradiation

The ultraviolet B (UVB) component of sunlight causes non-melanoma skin cancers due to the damage it inflicts on genomic DNA. The response of epidermal keratinocytes to sunlight depends on the dose of UVB received and the severity of the damage to the DNA. Mild DNA damage typically induces DNA-repair pathways and cell survival, while severe DNA damage provokes apoptosis. Primary human keratinocytes grown in serum-free media respond in a similar manner to UVB irradiation. However, we observed that keratinocytes are exquisitely more susceptible to UVB-induced apoptosis if the growth medium is depleted of exogenous growth factors. Therefore, an exogenous growth factor could provide protection from UVB-induced apoptosis. We found that the only growth factor that provided protection from UVB-induced apoptosis was insulin and that the protective effect elicited by insulin was not due to binding the insulin receptor but, rather, to activation of the insulin-like growth factor-1 (IGF-1) receptor. Additionally, activation of the IGF-1 receptor in combination with UVB irradiation induced keratinocytes to become post-mitotic. This survival function of the IGF-1 receptor in response to UVB irradiation was influenced by activation of phosphatidylinositol-3 kinase and MAP kinase. Prior to UVB irradiation, insulin or IGF-1 had little to no effect on cell growth or viability. Therefore, activation of the IGF-1 receptor in conjunction with UVB irradiation promotes keratinocyte survival at the expense of cell proliferation.

Subphysiological concentrations of extracellular calcium sensitize normal human keratinocytes to UVB-induced apoptosis

Normal human keratinocytes are stimulated to proliferate in serum-free medium containing subphysiological concentrations of calcium (0.09 mM, low calcium). In this study, we examined the effect of increased levels of extracellular calcium (2.0 mM, normal calcium) on UVB-induced apoptosis. Apoptosis was assessed by changes in cellular morphology, annexind V-FITC flow cytometry, and the formation of internucleosomal DNA ladders. High doses of UVB induced keratinocytes grown in low calcium medium to undergo apoptosis. In contrast, keratinocytes grown for 72 h in normal calcium medium were completely resistant to UVB-induced apoptosis. No apoptosis was observed even at UVB doses as high as 1200 J/m2. However, despite the lack of UVB-induced cell death, keratinocytes grown in normal calcium medium lost the ability to proliferate following high levels of UVB irradiation. High doses of UVB also increased the expression of the differentiation-specific proteins involucrin and cytokeratin 10 in a dose-dependent manner. In addition, growth in normal calcium medium lowered the UVB-induced stimulation of the p53 protein and altered the normal subcellular localization pattern of p53. UVB irradiation of human keratinocytes grown in normal calcium medium may be inducing further cell differentiation in the absence of overt cell death.

Melanoma-in-transit presenting as panniculitis

Malignant melanoma presenting as an inflammatory skin metastasis has been described but is an exceedingly rare phenomenon. We report an unusual case of a patient who developed right leg lesions that were initially thought to be infectious in origin. There was no resolution of these lesions with antibiotic therapy, and the patient subsequently underwent an incisional biopsy that showed atypical S-100 positive cells within dermal vessels. On further questioning, the patient revealed that 20 years earlier she had a pigmented lesion removed from her right posterior calf. Review of that material revealed malignant melanoma, approximately 3.2 mm in depth. Although the patient was subsequently treated with a right groin lymph node dissection and isolated limb perfusion chemotherapy, she has continued to develop locally recurrent disease. This case is unusual both in terms of clinical presentation and interval of disease progression.

Renal dietitians' perspective: identification, prevalence, and intervention for malnutrition in dialysis patients in Texas

OBJECTIVE

Determine the prevalence of malnutrition per facility standards; examine interventions used to treat malnutrition; and share experiences, concerns, and solutions to problems in the management of malnutrition in dialysis patients in Texas.

DESIGN

Structured survey questionnaires.

SETTING

196 outpatient hemodialysis (HD) and 86 peritoneal dialysis (PD) programs in End-Stage Renal Disease (ESRD) Network of Texas, Inc.

PARTICIPANTS

Renal dietitians who worked in Texas dialysis facilities that treated chronic, outpatient adult, and pediatric ESRD patients on HD or PD. MEASIRES: Criteria used to identify malnourished patients, prevalence of malnutrition in dialysis recipients, prevalence and types of interventions used to manage malnourished patients, and participation in quality management activities among renal dietitians.

RESULTS

For facilities that treated both HD and PD patients in 1996: (1) a significantly greater proportion of PD patients were identified as malnourished than HD patients; (2) facilities that had a high percentage of malnourished HD patients also had a high percentage of malnourished PD patients; (3) a significantly greater proportion of PD patients received commercial nutrition supplements than HD patients; and (4) use of tube feedings, intradialytic parenteral nutrition, intraperitoneal parenteral nutrition, and total parenteral nutrition among HD and PD patients decreased significantly from the past to the current survey year. Renal dietitians shared their experiences, concerns and solutions to problems in the management of malnutrition in this population.

CONCLUSION

Results indicate a need to improve the nutritional status of malnourished dialysis patients, to increase consideration of tube feedings as viable nutrient delivery routes, and to maximize involvement of renal dietitians in the quality management process. With the cooperative effort of staff, care givers, patients, and family, early identification and appropriate interventions may improve the nutritional status and quality of life of dialysis patients. This is a US government work. There are no restrictions on its use.

Increasing immunogenicity of antigens fused to Ig-binding proteins by cell surface targeting

Fusion of antigenic proteins to Ig-binding proteins such as protein A from Staphylococcus aureus and its derived ZZ fragment is known to increase immunogenicity of the fused Ag in vivo. To shed light on the origin of this effect, we used snake toxins as Ags and observed that 1) fusion of toxins to ZZ enhanced their presentation to a toxin-specific T cell hybridoma (T1B2), using A20 B lymphoma cells, splenocytes, or peritoneal exudate cells as APCs; 2) this enhancement further increased when the number of fused Ig-binding domains varied from two with ZZ to five with protein A; and 3) the phenomenon vanished when the fusion protein was preincubated with an excess of free ZZ or when P388D1 monocytes cells were used as APCs. Therefore, ZZ-fused toxins are likely to be targeted to surface Igs of APCs by their ZZ moiety. Furthermore, ZZ-alpha and toxin alpha stimulated similar profiles of toxin-specific T cells in BALB/c mice, suggesting a comparable processing and presentation in vivo for both toxin forms. To improve the targeting efficiency, ZZ-alpha was noncovalently complexed to various Igs directed to different cell surface components of APCs. The resulting complexes were up to 10(3)-fold more potent than the free toxin at stimulating T1B2. Also, they elicited both a T cell and an Ab response in BALB/c mice, without the need of any adjuvant. This simple approach may find practical applications by increasing the immunogenicity of recombinant proteins without the use of adjuvant.

Pseudopeptide ligands for MHC II-restricted T cells

The potential therapeutic use of peptides to activate or anergize specific T cells is seriously limited by their susceptibility to proteolytic degradation. Classically, peptides are stabilized by incorporation of non-natural modifications including main chain modifications. In the case of MHC II-restricted peptides, the peptide backbone actively participates to the interaction with the MHC molecule and hence may preclude the peptidomimetic approach. We thus investigated whether a single amide bond modification influenced the peptide capacity to bind to a MHC II molecule and to stimulate specific T cells. Twenty pseudopeptide analogs of the I-Ed binder 24-36 peptide, whose sequence was derived from a snake neurotoxin, were obtained by replacing each amide bond of the peptide central part, by either a reduced psi[CH2-NH] or N-methylated psi[CO-NMe] peptide bond. In agreement with the major interacting role played by the peptide backbone, several peptides displayed a low, if any, capacity to bind to the MHC II molecule and did not lead to T cell stimulation. However, one-third of the peptides were almost as active as the 24-36 peptide in I-Ed binding assays and one-fifth in T cell stimulation assays. Among them, two pseudopeptides displayed native-like activity. Good binders were not necessarily good at stimulating T cells, demonstrating that main chain modification also affected T cell recognition. We thus showed that a peptidomimetic approach could create a new type of MHC II ligand to control T cell responses.

RCN survey of gynaecology services after the NHS reforms

This paper presents the results of a survey conducted by the Royal College of Nursing (RCN) Gynaecology Nursing Forum. In late 1994/early 1995, a questionnaire was used to collect data from qualified nurses providing gynaecology hospital services throughout the UK. The questionnaire gathered information about the extent and impact of service reconfigurations following the 1989 NHS reforms (DoH 1989). The article describes these and recommends how specialist nurses can capitalise on the changes in the best interests of their patients.

A potassium-channel toxin from the sea anemone Bunodosoma granulifera, an inhibitor for Kv1 channels. Revision of the amino acid sequence, disulfide-bridge assignment, chemical synthesis, and biological activity

The potassium channel toxin secreted by the sea anemone Bunodosoma granulifera (BgK) is a 37-amino-acid peptide containing three disulfide bridges. Because a synthetic peptide corresponding to the reported sequence of BgK was found not to fold properly, the sequence was determined again. The new sequence differed from the previous one in the C-terminal tetrapeptide, which contains two cysteines involved in disulfide bridging. The revised sequence is: V C R D W F K E T A C R H A K S L G N C R T S Q K Y R A N C A K T C E L C. The toxin BgK was synthesized according to the new sequence and folded successfully. Disulfide bridges were assigned by peptide mapping on both natural and synthetic forms to be between Cys2-Cys37, Cys11-Cys30 and Cys20-Cys34. The toxin contains a C-terminal free carboxylate as shown by comparing the native toxin with two synthetic peptides containing the C-terminus in either the carboxylate or carboxamido form. Synthetic BgK inhibits binding of 125I-alpha-dendrotoxin to rat brain synaptosomal membranes, similarly to natural BgK (nanomolar range). No activity was observed on maxi-K+ channels incorporated into planar lipid bilayers. The ability of BgK to block voltage-dependent K+ channels was determined from recordings of whole cell currents in Xenopus oocytes injected with cRNA encoding three cloned Kv1 channels (Kv1.1, Kv1.2, Kv1.3) and one Kv3 (Kv3.1) channel. The Shaker-related Kv1 channels are equally affected by BgK, while the Shaw-related channel Kv3.1 is insensitive up to 0.125 microM toxin. Indeed, half blockage of the current through the three Kv1 channels tested occurred in the same concentration range (Kd = 6 nM for Kv1.1, 15 nM for Kv1.2, 10 nM for Kv1.3). The specificity of BgK for the Shaker-related K+ channels indicates that BgK is able to discriminate a large group of neuronal Kv1 channels in situ. The sequence, the disulfide bridge pattern, the secondary structure and the biological activity of BgK demonstrated that the sea anemone toxins, i.e. BgK, ShK and Kaliseptine, constitute novel molecular probes useful for investigating K+ channel properties.

On the convergent evolution of animal toxins. Conservation of a diad of functional residues in potassium channel-blocking toxins with unrelated structures

BgK is a K+ channel-blocking toxin from the sea anemone Bunodosoma granulifera. It is a 37-residue protein that adopts a novel fold, as determined by NMR and modeling. An alanine-scanning-based analysis revealed the functional importance of five residues, which include a critical lysine and an aromatic residue separated by 6.6 +/- 1.0 A. The same diad is found in the three known homologous toxins from sea anemones. More strikingly, a similar functional diad is present in all K+ channel-blocking toxins from scorpions, although these toxins adopt a distinct scaffold. Moreover, the functional diads of potassium channel-blocking toxins from sea anemone and scorpions superimpose in the three-dimensional structures. Therefore, toxins that have unrelated structures but similar functions possess conserved key functional residues, organized in an identical topology, suggesting a convergent functional evolution for these small proteins.

Ultraviolet B-radiation dose influences the induction of apoptosis and p53 in human keratinocytes

p53 is a tumor suppressor gene that has been implicated in a number of important cellular processes, including DNA repair and apoptosis. Genomic damage in human keratinocytes caused by ultraviolet B (UVB) irradiation has been shown to induce both apoptosis and p53 expression. We have previously observed that p53 expression in cultured normal human keratinocytes is predominantly perinuclear; however, exposure of cells to UVB radiation induces a major shift of p53 expression to the nucleus. Using terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labeling, internucleosomal DNA ladders and flow cytometry, we correlated observed changes in p53 expression with the induction of apoptosis at low, intermediate and high doses of UVB radiation. High doses of UVB radiation induced cells to undergo apoptosis, whereas UVB radiation at low doses did not induce apoptosis but appeared to stimulate repair of the DNA damage induced by UVB radiation. Intermediate doses of UVB radiation induced a heterogeneous population of cells to undergo either DNA repair or apoptosis. The level of UVB radiation dose also influenced the induced cellular localization of p53. These observed differences in p53 cellular localization correlated with the induction of DNA repair or apoptosis. In cells undergoing apoptosis, p53 protein was found within the blebs of the degenerating nuclei. Our data give support to increasing evidence that p53 may play a role in both the repair of UV-radiation-induced DNA damage and the induction of apoptosis, and may function as a central control checkpoint in response to UVB-radiation-induced DNA damage.

Functional-lesion investigation of developmental stuttering with positron emission tomography

Positron emission tomographic (PET) H2(15)O measurements of resting-state regional cerebral blood flow (CBF) were obtained in 29 right-handed men, 10 of whom stuttered and 19 of whom did not. PET images were analyzed by sampling 74 regions of interest (ROIs), 37 per hemisphere. ROI placement was guided both physiologically and anatomically. Physiological ROI placement was based on speech motor activations. Anatomical ROIs were positioned by reference to a stereotactic, neurosurgical atlas with positions confirmed and finely adjusted by co-registered magnetic-resonance images (MRIs). For all subjects, PET and MR images were normal to visual inspection. Highly significant (p < 0.0001) between-region and between-hemisphere effects were found for both groups, as have been previously reported for normal subjects, but no significant between-group differences were found for any regional CBF values. Analysis by a laterality index found a weakly significant between-groups effect (p = 0.04) that was isolated to five regions, four of which are implicated in speech or hearing. However, these regional laterality effects showed no consistent directionality, nor did these regions have absolute differences in regional blood flow between groups. Present findings do not support recent suggestions that developmental stuttering is associated with abnormalities of brain blood flow at rest. Rather, our findings indicate an essentially normal functional brain terrain with a small number of minor differences in hemispheric symmetry.