Multi-omic analysis of the cardiac cellulome defines a vascular contribution to cardiac diastolic dysfunction in obese female mice

Coronary microvascular dysfunction (CMD) is associated with cardiac dysfunction and predictive of cardiac mortality in obesity, especially in females. Clinical data further support that CMD associates with development of heart failure with preserved ejection fraction and that mineralocorticoid receptor (MR) antagonism may be more efficacious in obese female, versus male, HFpEF patients. Accordingly, we examined the impact of smooth muscle cell (SMC)-specific MR deletion on obesity-associated coronary and cardiac diastolic dysfunction in female mice. Obesity was induced in female mice via western diet (WD) feeding alongside littermates fed standard diet. Global MR blockade with spironolactone prevented coronary and cardiac dysfunction in obese females and specific deletion of SMC-MR was sufficient to prevent obesity-associated coronary and cardiac diastolic dysfunction. Cardiac gene expression profiling suggested reduced cardiac inflammation in WD-fed mice with SMC-MR deletion independent of blood pressure, aortic stiffening, and cardiac hypertrophy. Further mechanistic studies utilizing single-cell RNA sequencing of non-cardiomyocyte cell populations revealed novel impacts of SMC-MR deletion on the cardiac cellulome in obese mice. Specifically, WD feeding induced inflammatory gene signatures in non-myocyte populations including B/T cells, macrophages, and endothelium as well as increased coronary VCAM-1 protein expression, independent of cardiac fibrosis, that was prevented by SMC-MR deletion. Further, SMC-MR deletion induced a basal reduction in cardiac mast cells and prevented WD-induced cardiac pro-inflammatory chemokine expression and leukocyte recruitment. These data reveal a central role for SMC-MR signaling in obesity-associated coronary and cardiac dysfunction, thus supporting the emerging paradigm of a vascular origin of cardiac dysfunction in obesity.

Retrospective analysis of locked versus non-locked plating of distal fibula fractures

INTRODUCTION

Unstable distal fibular fractures have traditionally been treated with open reduction internal fixation using a 1/3 tubular non-locked plate (compression plating). Locked plating is a newer technique that has become more popular despite the lack of clinical data supporting improved outcomes. The cost of locked plating is almost four times that of compression plating. We compared rates of reoperation due to implant failure, infection, and symptomatic device between compression and locked plating in open reduction internal fixation of distal fibular fractures METHODS: A retrospective study was performed at a level one trauma center over a ten-year period (2008-2017). Patients who were 18 and older and treated for unstable ankle fractures with locking or non-locking plate were included in this study. Patient charts were reviewed by orthopedic trauma surgeons to identify whether patients were treated with a 1/3 tubular non-locking or pre-contoured locked plate and to determine the cause of reoperation.

RESULTS

In total, 442 patients were identified with 203 in the non-locked 1/3 tubular plate group and 239 in the pre-contoured locked plate group. A total of 38 patients (8.6%) underwent device removal with a higher proportion of patients in the non-locked 1/3 tubular plate cohort (11.3% vs. 6.3%, p = 0.059). Statistically significant differences in reasons for reoperation were found for symptomatic implant (78.3% vs. 46.7%, p = 0.045) and infection (8.7% vs 53.3%., p < 0.01). Of patients who had device removal for symptomatic implant in the compression plating cohort, 13 (72.2%) had lateral positioning and 5 (27.8%) had posterior positioning (p < 0.01) whereas there was no statistical difference in plate positioning in the locked cohort. Of all medical comorbidities identified, only diabetes was associated with a higher rate of infection-related reoperations (83.3% vs. 15.6%, p < 0.01).

CONCLUSIONS

Both compression and locked plate techniques demonstrated low reoperation rates. Compression plating with 1/3 tubular plates placed laterally more often resulted in reoperation due to symptomatic implant but had fewer complications of infection. Given that the cost is significantly less, 1/3 tubular plating placed posteriorly may be preferred to decrease the risks of symptomatic implant and infection.

Reversion inducing cysteine rich protein with Kazal motifs and cardiovascular diseases: The RECKlessness of adverse remodeling

The Reversion Inducing Cysteine Rich Protein With Kazal Motifs (RECK) is a glycosylphosphatidylinositol (GPI) anchored membrane-bound regulator of matrix metalloproteinases (MMPs). It is expressed throughout the body and plays a role in extracellular matrix (ECM) homeostasis and inflammation. In initial studies, RECK expression was found to be downregulated in various invasive cancers and associated with poor prognostic outcome. Restoring RECK, however, has been shown to reverse the metastatic phenotype. Downregulation of RECK expression is also reported in non-malignant diseases, such as periodontal disease, renal fibrosis, and myocardial fibrosis. As such, RECK induction has therapeutic potential in several chronic diseases. Mechanistically, RECK negatively regulates various matrixins involved in cell migration, proliferation, and adverse remodeling by targeting the expression and/or activation of multiple MMPs, A Disintegrin And Metalloproteinase Domain-Containing Proteins (ADAMs), and A Disintegrin And Metalloproteinase With Thrombospondin Motifs (ADAMTS). Outside of its role in remodeling, RECK has also been reported to exert anti-inflammatory effects. In cardiac diseases, for example, it has been shown to counteract several downstream effectors of Angiotensin II (Ang-II) that play a role in adverse cardiac and vascular remodeling, such as Interleukin-6 (IL-6)/IL-6 receptor (IL-6R)/glycoprotein 130 (IL-6 signal transducer) signaling and Epidermal Growth Factor Receptor (EGFR) transactivation. This review article focuses on the current understanding of the multifunctional effects of RECK and how its downregulation may contribute to adverse cardiovascular remodeling.

Chronic Elevation of Endothelin-1 Alone May Not Be Sufficient to Impair Endothelium-Dependent Relaxation

Endothelin-1 (ET-1) is a powerful vasoconstrictor peptide considered to be causally implicated in hypertension and the development of cardiovascular disease. Increased ET-1 is commonly associated with reduced NO bioavailability and impaired vascular function; however, whether chronic elevation of ET-1 directly impairs endothelium-dependent relaxation (EDR) remains elusive. Herein, we report that (1) prolonged ET-1 exposure (ie, 48 hours) of naive mouse aortas or cultured endothelial cells did not impair EDR or reduce eNOS (endothelial NO synthase) activity, respectively (P>0.05); (2) mice with endothelial cell-specific ET-1 overexpression did not exhibit impaired EDR or reduced eNOS activity (P>0.05); (3) chronic (8 weeks) pharmacological blockade of ET-1 receptors in obese/hyperlipidemic mice did not improve aortic EDR or increase eNOS activity (P>0.05); and (4) vascular and plasma ET-1 did not inversely correlate with EDR in resistance arteries isolated from human subjects with a wide range of ET-1 levels (r=0.0037 and r=-0.1258, respectively). Furthermore, we report that prolonged ET-1 exposure downregulated vascular UCP-1 (uncoupling protein-1; P<0.05), which may contribute to the preservation of EDR in conditions characterized by hyperendothelinemia. Collectively, our findings demonstrate that chronic elevation of ET-1 alone may not be sufficient to impair EDR.

Aldosterone impairs coronary adenosine-mediated vasodilation via reduced functional expression of Ca2+-activated K+ channels

Elevated plasma aldosterone (Aldo) levels are associated with greater risk of cardiac ischemic events and cardiovascular mortality. Adenosine-mediated coronary vasodilation is a critical cardioprotective mechanism during ischemia; however, whether this response is impaired by increased Aldo is unclear. We hypothesized that chronic Aldo impairs coronary adenosine-mediated vasodilation via downregulation of vascular K⁺ channels. Male C57BL/6J mice were treated with vehicle (Con) or subpressor Aldo for 4 wk. Coronary artery function, assessed by wire myography, revealed Aldo-induced reductions in vasodilation to adenosine and the endothelium-dependent vasodilator acetylcholine but not to the nitric oxide donor sodium nitroprusside. Coronary vasoconstriction to endothelin-1 and the thromboxane A₂ mimetic U-46619 was unchanged by Aldo. Additional mechanistic studies revealed impaired adenosine A_2A, not A_2B, receptor-dependent vasodilation by Aldo with a tendency for Aldo-induced reduction of coronary A_2A gene expression. Adenylate cyclase inhibition attenuated coronary adenosine dilation but did not eliminate group differences, and adenosine-stimulated vascular cAMP production was similar between Con and Aldo mice. Similarly, blockade of inward rectifier K⁺ channels reduced but did not eliminate group differences in adenosine dilation whereas group differences were eliminated by blockade of Ca²⁺-activated K⁺ (K_Ca) channels that blunted and abrogated adenosine and A_2A-dependent dilation, respectively. Gene expression of several coronary K_Ca channels was reduced by Aldo. Together, these data demonstrate Aldo-induced impairment of adenosine-mediated coronary vasodilation involving blunted A_2A-K_Ca-dependent vasodilation, independent of blood pressure, providing important insights into the link between plasma Aldo and cardiac mortality and rationale for aldosterone antagonist use to preserve coronary microvascular function.NEW & NOTEWORTHY Increased plasma aldosterone levels are associated with worsened cardiac outcomes in diverse patient groups by unclear mechanisms. We identified that, in male mice, elevated aldosterone impairs coronary adenosine-mediated vasodilation, an important cardioprotective mechanism. This aldosterone-induced impairment involves reduced adenosine A_2A, not A_2B, receptor-dependent vasodilation associated with downregulation of coronary K_Ca channels and does not involve altered adenylate cyclase/cAMP signaling. Importantly, this effect of aldosterone occurred independent of changes in coronary vasoconstrictor responsiveness and blood pressure.

Canagliflozin Inhibits Human Endothelial Cell Proliferation and Tube Formation

Recent clinical trials revealed that sodium-glucose co-transporter 2 (SGLT2) inhibitors significantly reduce cardiovascular events in type 2 diabetic patients, however, canagliflozin increased limb amputations, an effect not seen with other SGLT2 inhibitors. Since endothelial cell (EC) dysfunction promotes diabetes-associated vascular disease and limb ischemia, we hypothesized that canagliflozin, but not other SGLT2 inhibitors, impairs EC proliferation, migration, and angiogenesis. Treatment of human umbilical vein ECs (HUVECs) with clinically relevant concentrations of canagliflozin, but not empagliflozin or dapagliflozin, inhibited cell proliferation. In particular, 10 μM canagliflozin reduced EC proliferation by approximately 45%. The inhibition of EC growth by canagliflozin occurred in the absence of cell death and was associated with diminished DNA synthesis, cell cycle arrest, and a striking decrease in cyclin A expression. Restoration of cyclin A expression via adenoviral-mediated gene transfer partially rescued the proliferative response of HUVECs treated with canagliflozin. A high concentration of canagliflozin (50 μM) modestly inhibited HUVEC migration by 20%, but markedly attenuated their tube formation by 65% and EC sprouting from mouse aortas by 80%. A moderate 20% reduction in HUVEC migration was also observed with a high concentration of empagliflozin (50 μM), while neither empagliflozin nor dapagliflozin affected tube formation by HUVECs. The present study identified canagliflozin as a robust inhibitor of human EC proliferation and tube formation. The anti-proliferative action of canagliflozin occurs in the absence of cell death and is due, in part, to the blockade of cyclin A expression. Notably, these actions are not seen with empagliflozin or dapagliflozin. The ability of canagliflozin to exert these pleiotropic effects on ECs may contribute to the clinical actions of this drug.

Environmentally enriched pigs have transcriptional profiles consistent with neuroprotective effects and reduced microglial activity

Environmental enrichment (EE) is widely used to study the effects of external factors on brain development, function and health in rodent models, but very little is known of the effects of EE on the brain in a large animal model such as the pig. Twenty-four young pigs (aged 5 weeks at start of study, 1:1 male: female ratio) were housed in environmentally enriched (EE) pens and provided with additional enrichment stimulation (a bag filled with straw) once daily. Litter, weight and sex matched controls n= (24) were housed in barren (B) conditions. Behaviour was recorded on alternate days from study day 10. After 21 days, RNA-sequencing of the frontal cortex of male piglets culled one hour after the enrichment stimulation, but not those at 4 h after stimulation, showed upregulation of genes involved in neuronal activity and synaptic plasticity in the EE compared to the B condition. This result is mirrored in the behavioural response to the stimulation which showed a peak in activity around the 1 h time-point. By contrast, EE piglets displayed a signature consistent with a relative decrease in microglial activity compared to those in the B condition. These results confirm those from rodents, suggesting that EE may also confer neuronal health benefits in large mammal models, through a potential relative reduction in neuroinflammatory process and increase in neuroprotection driven by an enrichment-induced increase in behavioural activity.

Mineralocorticoid receptor antagonism reverses diabetes-related coronary vasodilator dysfunction: A unique vascular transcriptomic signature

Coronary microvascular dysfunction predicts and may be a proximate cause of cardiac dysfunction and mortality in diabetes; however, few effective treatments exist for these conditions. We recently demonstrated that mineralocorticoid receptor (MR) antagonism reversed cardiovascular dysfunction in early-stage obesity/insulin resistance. The mechanisms underlying this benefit of MR antagonism and its relevance in the setting of long-term obesity complications like diabetes; however, remain unclear. Thus, the present study evaluated the impact of MR antagonism on diabetes-related coronary dysfunction and defines the MR-dependent vascular transcriptome in the Otsuka Long-Evans Tokushima Fatty (OLETF) rat recapitulating later stages of human diabetes. OLETF rats were treated with spironolactone (Sp) and compared to untreated OLETF and lean Long-Evans Tokushima Otsuka rats. Sp treatment attenuated diabetes-associated adipose and cardiac inflammation/fibrosis and improved coronary endothelium-dependent vasodilation but did not alter enhanced coronary vasoconstriction, blood pressure, or metabolic parameters in OLETF rats. Further mechanistic studies using RNA deep sequencing of OLETF rat aortas revealed 157 differentially expressed genes following Sp including upregulation of genes involved in the molecular regulation of nitric oxide bioavailability (Hsp90ab1, Ahsa1, Ahsa2) as well as novel changes in α_1D adrenergic receptors (Adra1d), cyclooxygenase-2 (Ptgs2), and modulatory factors of these pathways (Ackr3, Acsl4). Further, Ingenuity Pathway Analysis predicted inhibition of upstream inflammatory regulators by Sp and inhibition of 'migration of endothelial cells', 'differentiation of smooth muscle', and 'angiogenesis' biological functions by Sp in diabetes. Thus, this study is the first to define the MR-dependent vascular transcriptome underlying treatment of diabetes-related coronary microvascular dysfunction by Sp.

Inherited pulmonary cylindromas: extending the phenotype of CYLD mutation carriers

Background

Germline mutations in the tumour suppressor gene CYLD are recognized to be associated with the development of multiple cutaneous cylindromas. We encountered such a patient who presented with breathlessness because of multiple pulmonary cylindromas.

Objectives

To search for clinical and radiological features of multiple pulmonary cylindromas in a cohort of 16 patients with CYLD mutations.

Methods

A retrospective case‐note review was carried out in a tertiary dermatogenetics clinic where CYLD mutation carriers are reviewed on an annual basis. In‐depth investigation was carried out for patients with pulmonary tumours.

Results

Four patients had radiological imaging of their lungs, of which two had multiple pulmonary cylindromas that were confirmed histologically. Serial computed tomography monitoring allowed for pre‐emptive endobronchial laser ablation, preventing major airway obstruction and pulmonary collapse.

Conclusions

Pulmonary cylindromas are an unrecognized, but infrequently symptomatic, aspect of the phenotype in these patients that can have implications for patient care. They should be considered in patients with a high tumour burden that present with respiratory symptoms, and where appropriate, monitored with serial imaging.

What's already known about this topic?

Germline mutations in the tumour suppressor gene CYLD are recognized to be associated with the development of multiple cutaneous cylindromas, spiradenomas and trichoepitheliomas.

Beyond the skin, salivary gland tumours are seen in less than approximately 5% of patients, but otherwise the tropism of this disease is recognized as exclusively cutaneous.

What does this study add?

We report multiple pulmonary cylindromas in two patients out of a series of 16 patients, a previously unreported aspect of this genetic disease.

Deep phenotyping with radiological, histological and genetic approaches provides evidence that supports that these tumours are similar to cutaneous cylindromas and share a cytokeratin signature seen in cutaneous cylindroma.

What is the translational message?

Patients with this rare disease should be investigated if they present with new symptoms of respiratory disease.

These data inform the clinical surveillance and management of patients with this rare condition and also inform the longstanding debate on benign metastases.

https://doi.org/10.1111/bjd.17046 available online

https://goo.gl/Uqv3dl

Dipeptidyl Peptidase-4 Inhibition With Saxagliptin Ameliorates Angiotensin II-Induced Cardiac Diastolic Dysfunction in Male Mice

Activation of the renin-angiotensin-aldosterone system is common in hypertension and obesity and contributes to cardiac diastolic dysfunction, a condition for which no treatment currently exists. In light of recent reports that antihyperglycemia incretin enhancing dipeptidyl peptidase (DPP)-4 inhibitors exert cardioprotective effects, we examined the hypothesis that DPP-4 inhibition with saxagliptin (Saxa) attenuates angiotensin II (Ang II)-induced cardiac diastolic dysfunction. Male C57BL/6J mice were infused with either Ang II (500 ng/kg/min) or vehicle for 3 weeks receiving either Saxa (10 mg/kg/d) or placebo during the final 2 weeks. Echocardiography revealed Ang II-induced diastolic dysfunction, evidenced by impaired septal wall motion and prolonged isovolumic relaxation, coincident with aortic stiffening. Ang II induced cardiac hypertrophy, coronary periarterial fibrosis, TRAF3-interacting protein 2 (TRAF3IP2)-dependent proinflammatory signaling [p-p65, p-c-Jun, interleukin (IL)-17, IL-18] associated with increased cardiac macrophage, but not T cell, gene expression. Flow cytometry revealed Ang II-induced increases of cardiac CD45+F4/80+CD11b+ and CD45+F4/80+CD11c+ macrophages and CD45+CD4+ lymphocytes. Treatment with Saxa reduced plasma DPP-4 activity and abrogated Ang II-induced cardiac diastolic dysfunction independent of aortic stiffening or blood pressure. Furthermore, Saxa attenuated Ang II-induced periarterial fibrosis and cardiac inflammation, but not hypertrophy or cardiac macrophage infiltration. Analysis of Saxa-induced changes in cardiac leukocytes revealed Saxa-dependent reduction of the Ang II-mediated increase of cardiac CD11c messenger RNA and increased cardiac CD8 gene expression and memory CD45+CD8+CD44+ lymphocytes. In summary, these results demonstrate that DPP-4 inhibition with Saxa prevents Ang II-induced cardiac diastolic dysfunction, fibrosis, and inflammation associated with unique shifts in CD11c-expressing leukocytes and CD8+ lymphocytes.

Detection of Borrelia burgdorferi and Anaplasma phagocytophilum in the black-legged tick, Ixodes scapularis, within southwestern Pennsylvania

Prevalence studies of Borrelia burgdorferi and Anaplasma phagocytophilum have been rare for ticks from southwestern Pennsylvania. We collected 325 Ixodes scapularis ticks between 2011 and 2012 from four counties in southwestern Pennsylvania. We tested for the presence of Borrelia burgdorferi and Anaplasma phagocytophilum using PCR. Of the ticks collected from Pennsylvania, B. burgdorferi (causative agent of Lyme disease) was present in 114/325 (35%) and Anaplasma phagocytophilum (causative agent of Human Granulocytic Anaplasmosis) was present in 48/325 (15%) as determined by PCR analysis.

Constraint of the astrophysical ^{26g}Al(p,γ)^{27}Si destruction rate at stellar temperatures

The Galactic 1.809-MeV γ-ray signature from the β decay of ^{26g}Al is a dominant target of γ-ray astronomy, of which a significant component is understood to originate from massive stars. The ^{26g}Al(p,γ)^{27}Si reaction is a major destruction pathway for ^{26g}Al at stellar temperatures, but the reaction rate is poorly constrained due to uncertainties in the strengths of low-lying resonances in ^{27}Si. The ^{26g}Al(d,p)^{27}Al reaction has been employed in inverse kinematics to determine the spectroscopic factors, and hence resonance strengths, of proton resonances in ^{27}Si via mirror symmetry. The strength of the 127-keV resonance is found to be a factor of 4 higher than the previously adopted upper limit, and the upper limit for the 68-keV resonance has been reduced by an order of magnitude, considerably constraining the ^{26g}Al destruction rate at stellar temperatures.

Profiling gene expression to distinguish the likely active diazotrophs from a sea of genetic potential in marine sediments

Nitrogen (N) cycling microbial communities in marine sediments are extremely diverse, and it is unknown whether this diversity reflects extensive functional redundancy. Sedimentary denitrifiers remove significant amounts of N from the coastal ocean and diazotrophs are typically regarded as inconsequential. Recently, N fixation has been shown to be a potentially important source of N in estuarine and continental shelf sediments. Analysis of expressed genes for nitrite reductase (nirS) and a nitrogenase subunit (nifH) was used to identify the likely active denitrifiers and nitrogen fixers in surface sediments from different seasons in Narragansett Bay (Rhode Island, USA). The overall diversity of diazotrophs expressing nifH decreased along the estuarine gradient from the estuarine head to an offshore continental shelf site. Two groups of sequences related to anaerobic sulphur/iron reducers and sulphate reducers dominated libraries of expressed nifH genes. Quantitative polymerase chain reaction (qPCR) and quantitative reverse transcription polymerase chain reaction (qRT-PCR) data shows the highest abundance of both groups at a mid bay site, and the highest nifH expression at the head of the estuary, regardless of season. Several potential environmental factors, including water temperature, oxygen concentration and metal contamination, may influence the abundance and nifH expression of these two bacterial groups.

Halo nucleus 11Be: a spectroscopic study via neutron transfer

The best examples of halo nuclei, exotic systems with a diffuse nuclear cloud surrounding a tightly bound core, are found in the light, neutron-rich region, where the halo neutrons experience only weak binding and a weak, or no, potential barrier. Modern direct-reaction measurement techniques provide powerful probes of the structure of exotic nuclei. Despite more than four decades of these studies on the benchmark one-neutron halo nucleus 11Be, the spectroscopic factors for the two bound states remain poorly constrained. In the present work, the 10Be(d,​p) reaction has been used in inverse kinematics at four beam energies to study the structure of 11Be. The spectroscopic factors extracted using the adiabatic model were found to be consistent across the four measurements and were largely insensitive to the optical potential used. The extracted spectroscopic factor for a neutron in an nℓj=2s(1/2) state coupled to the ground state of 10Be is 0.71(5). For the first excited state at 0.32 MeV, a spectroscopic factor of 0.62(4) is found for the halo neutron in a 1p(1/2) state.

Expression of muscarinic receptors by human macrophages

Macrophages increase in number and are highly activated in chronic obstructive pulmonary disease (COPD). Muscarinic receptor antagonists inhibit acetylcholine-stimulated release of neutrophilic chemoattractants, suggesting that acetylcholine may regulate macrophage responses. Therefore, expression and function of components of the non-neuronal cholinergic system in monocyte-macrophage cells was investigated. RNA was isolated from monocytes, monocyte-derived macrophages (MDMs), lung and alveolar macrophages from nonsmokers, smokers and COPD patients, and expression of the high-affinity choline transporter, choline acetyltransferase, vesicular acetylcholine transporter and muscarinic receptors (M(1)-M(5)) ascertained using real-time PCR. M(2) and M(3) receptor expression was confirmed using immunocytochemistry. Release of interleukin (IL)-8, IL-6 and leukotriene (LT)B(4) were measured by ELISA or EIA. All monocyte-macrophage cells expressed mRNA for components of the non-neuronal cholinergic system. Lung macrophages expressed significantly more M(1) mRNA compared with monocytes, and both lung macrophages and alveolar macrophages expressed the highest levels of M(3) mRNA. Expression of M(2) and M(3) protein was confirmed in MDMs and lung macrophages. Carbachol stimulated release of LTB(4) from lung macrophages (buffer 222.3 ± 75.1 versus carbachol 1,118 ± 622.4 pg · mL(-1); n = 15, p<0.05) but not IL-6 or IL-8. LTB(4) release was attenuated by the M(3) antagonist, 1,1-dimethyl-4-diphenylacetoxypiperidinium iodide (4-DAMP; half maximal effective concentration 5.2 ± 2.2 nM; n = 9). Stimulation of macrophage M(3) receptors promotes release of LTB(4), suggesting that anti-muscarinic agents may be anti-inflammatory.

Teaching serial position sequences to monkeys with a delayed matching-to-sample procedure

Comparison was made of two methods for training monkeys to "observe" a two-member serial position sequence by pressing two consecutively lighted keys and then to "report" the sequence by pressing the same two keys in the same order but without the lights. A fading technique involving gradual elimination of brightness cues from "reporting" keys was found more effective than a no-fading procedure in which the cues remained bright during training and then were suddenly removed. Animals that failed to learn to report a new sequence with the no-fading procedure sometimes developed behavior incompatible with that desired. They made repeated and specific errors that prematurely terminated trials of the sequence to-be-learned, even though the correct key was cued by a bright light. They behaved appropriately, however, on succeeding trials of other sequences. Thus, the errors were followed by trials on which reinforcement occurred. Manipulation of this contingency indicated its importance in maintaining the stereotyped error patterns.

Right and left heart failure in severe H1N1 influenza A infection

Influenza infection can affect cardiac function. The recent pandemic of H1N1 influenza A provided an opportunity to study echocardiographic findings in critically ill infected patients. We hypothesised that critically ill patients with H1N1 infection would have a higher incidence of right and left heart failure than is seen in unselected populations of patients with septic shock and/or acute respiratory distress syndrome (ARDS). We retrospectively studied all patients admitted to four intensive care units at three hospitals in Salt Lake County, UT, USA, with laboratory-confirmed H1N1 infection in whom a clinical echocardiogram was available. 23 out of 48 patients had qualifying echocardiograms. Right ventricular (RV) dilatation (50-80%) and at least moderate systolic impairment (23%) were common, higher than the range described in general populations with ARDS. Left ventricular systolic dysfunction was present in 17% of patients. No single echocardiographic parameter was associated with 28-day mortality or ventilator-free days to 28 days. Critically ill patients with H1N1 infection frequently exhibit right heart dilatation and failure. RV basal dilatation was extremely common. These patients have less left heart failure than expected on the basis of prior descriptions of influenza myopericarditis or of general populations of septic patients.

Genetic variation in components of dopamine neurotransmission impacts ventral striatal reactivity associated with impulsivity

Individual differences in traits such as impulsivity involve high reward sensitivity and are associated with risk for substance use disorders. The ventral striatum (VS) has been widely implicated in reward processing, and individual differences in its function are linked to these disorders. Dopamine (DA) plays a critical role in reward processing and is a potent neuromodulator of VS reactivity. Moreover, altered DA signaling has been associated with normal and pathological reward-related behaviors. Functional polymorphisms in DA-related genes represent an important source of variability in DA function that may subsequently impact VS reactivity and associated reward-related behaviors. Using an imaging genetics approach, we examined the modulatory effects of common, putatively functional DA-related polymorphisms on reward-related VS reactivity associated with self-reported impulsivity. Genetic variants associated with relatively increased striatal DA release (DRD2 -141C deletion) and availability (DAT1 9-repeat), as well as diminished inhibitory postsynaptic DA effects (DRD2 -141C deletion and DRD4 7-repeat), predicted 9-12% of the interindividual variability in reward-related VS reactivity. In contrast, genetic variation directly affecting DA signaling only in the prefrontal cortex (COMT Val158Met) was not associated with variability in VS reactivity. Our results highlight an important role for genetic polymorphisms affecting striatal DA neurotransmission in mediating interindividual differences in reward-related VS reactivity. They further suggest that altered VS reactivity may represent a key neurobiological pathway through which these polymorphisms contribute to variability in behavioral impulsivity and related risk for substance use disorders.

A strategy for systemic delivery of the oncolytic herpes virus HSV1716: redirected tropism by antibody-binding sites incorporated on the virion surface as a glycoprotein D fusion protein

We report on the ability of single-chain variable fragment (scFv) incorporated into the viral envelope to alter the tropism of herpes simplex virus (HSV) 1716. Using recombinant viruses expressing fusion proteins comprising cell-surface antigen-specific scFvs N terminus linked to amino acids 274-393 of gD, we demonstrated that the tropism of these HSV1716 variants was modified such that infection was mediated by the cognate antigen. Thus, an HSV1716 variant that expressed an anti-CD55 scFv targeting moiety linked to these gD residues was able to infect non-permissive Chinese hamster ovary cells expressing CD55 and this infection was specifically blocked by an anti-CD55 monoclonal antibody. Similarly, the infection efficiency of an HSV1716 variant for semi-permissive human leukaemic, CD38-positive cell lines was greatly improved by an anti-CD38 scFv targeting moiety linked to gD residues 274-393, and this enhanced infectivity was abrogated specifically by an anti-CD38 monoclonal antibody. Finally, intravenous/intraperitoneal injection of an HSV1716 variant displaying an anti-epidermal growth factor receptor (EGFR) scFv linked to residues 274-393 of gD enhanced destruction of subcutaneous EGFR-positive tumours in nude mice compared to unmodified HSV1716. Therefore, targeting of HSV1716 oncolysis to specific cell types through the display of entry mediating scFv/gD fusion proteins represents an efficient route for systemic delivery.

Cytotoxic effects of the oncolytic herpes simplex virus HSV1716 alone and in combination with cisplatin in head and neck squamous cell carcinoma

CONCLUSIONS

HSV1716 alone and combined with cisplatin was efficacious in destroying head and neck squamous cell carcinoma (HNSCC) cells. Combination treatment with HSV1716 and cisplatin gave additive efficacy. These results indicate that HSV1716 in combination with cisplatin could be of therapeutic value in HNSCC and warrants further investigation.

OBJECTIVES

HSV1716 is a replication competent herpes simplex virus which selectively replicates and lyses actively dividing cells but not normal or terminally differentiated cells. The objective of this study was to determine the efficacy of HSV1716 alone and in combination with cisplatin in HNSCC.

MATERIALS AND METHODS

Three HNSCC cell lines were studied; UM-SCC 14C, UM-SCC 22A and UM-SCC 22B. The permissivity of HSV1716 in these cell lines was determined using multicycle growth experiments. In vitro, cytotoxicity of HSV1716 and cisplatin was determined using an MTS proliferation assay. Isobologram analysis was used to determine the interaction between HSV1716 and cisplatin combination treatment.

RESULTS

The three HNSCC cell lines studied were permissive for HSV1716 replication. Cytotoxicity increased in a dose-dependent fashion in all three cell lines. Cisplatin was non-toxic to the virus. Isobologram analysis showed additive cytotoxicity when HSV1716 was combined with cisplatin in all three cell lines.

Role of peripheral hyperpolarization-activated cyclic nucleotide-modulated channel pacemaker channels in acute and chronic pain models in the rat

Hyperpolarization-activated, cyclic nucleotide-modulated (HCN) channels contribute to rhythmic spontaneous activity in the heart and CNS. Ectopic spontaneous neuronal activity has been implicated in the development and maintenance of acute and chronic hyperalgesia, allodynia and spontaneous pain. Previously, we documented that systemic administration of ZD7288, a specific blocker of pacemaker current (I(h)), decreased ectopic activity in dorsal root ganglion (DRG) and reversed tactile allodynia in spinal nerve ligated (SNL) rats [Chaplan SR, Guo HQ, Lee DH, Luo L, Liu C, Kuei C, Velumian AA, Butler MP, Brown SM, Dubin AE (2003) Neuronal hyperpolarization-activated pacemaker channels drive neuropathic pain. J Neurosci 23:1169-1178]. Spontaneous pain is the chief clinical manifestation of peripheral nerve injury; however, a role for I(h) in spontaneous pain has not been described. Here, in further rat studies, we report that systemic administration of ZD7288 reversed spontaneous pain induced by mild thermal injury (MTI) and tactile allodynia induced by SNL and MTI. In contrast, ZD7288 did not reduce thermal hyperalgesia. An important locus of action appears to be in the skin since intraplantar (local) administration of ZD7288 completely suppressed tactile allodynia arising from MTI and SNL and reduced spontaneous pain due to MTI. Immunohistochemical staining of plantar skin sections detected HCN1-HCN4 expression in mechanosensory structures (e.g., Meissner's corpuscles and Merkel cells). Collectively, these data suggest that expression and modulation of I(h) in the peripheral nervous system, including specialized sensory structures, may play a significant role in sensory processing and contribute to spontaneous pain and tactile allodynia.

Assessment of 123I-FIAU imaging of herpes simplex viral gene expression in the treatment of glioma

BACKGROUND

Herpes simplex virus 1716 (HSV1716), a selectively replication competent mutant of HSV1, is under investigation as an oncolytic viral therapy in human malignant glioma. As with similar therapies, a technique for measurement of viral replication and distribution over time following virus administration is required. Imaging expression of the HSV-thymidine kinase (HSV-tk) gene offers an opportunity for non-invasive assessment of viral distribution in living subjects. This is the first study to explore the use of HSV-tk as a reporter gene and radiolabelled thymidine analogue 5-[(123)I]iodo-1-(2-deoxy-2-fluoro-beta-D-arabinofuranosyl) uracil ((123)I-FIAU) as a marker substrate to non-invasively monitor HSV1716 replication in humans during treatment of high-grade glioma.

METHODS

I-FIAU brain SPECT imaging was undertaken in eight patients receiving intra-tumoural injection of HSV1716, before and after administration of the virus. Baseline images were acquired 3 days prior to virus administration and between 1 and 5 days following virus administration. Region of interest analysis was used to investigate whether there was an increase in (123)I-FIAU concentration following virus administration due to HSV-tk expression.

RESULT

Increased (123)I-FIAU accumulation due to HSV-tk expression was not detected in this study. The possible explanations for this finding are explored and design options for future studies are discussed.

Modified virtual reality technology for treatment of amblyopia

PURPOSE

The conventional patching/occlusion treatment for amblyopia sometimes gives disappointing results for a number of reasons: it is unpopular, prolonged, frequently resulting in poor or noncompliance, and also disrupts fusion. The aim of this research was to develop a novel virtual-reality (VR)-based display system that facilitates the treatment of amblyopia with both eyes stimulated simultaneously.

METHODS

We have adopted a multidisciplinary approach, combining VR expertise with a team of ophthalmologists and orthoptists to develop the Interactive Binocular Treatment (I-BiT) system. This system incorporates adapted VR technology and specially written software providing interactive 2D and 3D games and videos to the patient via a stereo (binocular) display, and a control screen for the clinician.

RESULTS

We developed a prototype research system designed for treatment of amblyopia in children.

CONCLUSIONS

The result is a novel way to treat amblyopia, which allows binocular treatment. It is interactive, and as it is partially software based, can be adapted to suit the age/ability, and needs of the patient. This means that the treatment can be made captivating and enjoyable. Further research is on-going to determine the efficacy of this new modality in the treatment of amblyopia.

Preliminary results from the use of the novel Interactive binocular treatment (I-BiT) system, in the treatment of strabismic and anisometropic amblyopia

BACKGROUND

We have developed a novel application of adapted virtual reality (VR) technology, for the binocular treatment of amblyopia. We describe the use of the system in six children.

METHODS

Subjects consisted of three conventional treatment 'failures' and three conventional treatment 'refusers', with a mean age of 6.25 years (5.42-7.75 years). Treatment consisted of watching video clips and playing interactive games with specifically designed software to allow streamed binocular image presentation.

RESULTS

Initial vision in the amblyopic eye ranged from 6/12 to 6/120 and post-treatment 6/7.5 to 6/24-1. Total treatment time was a mean of 4.4 h. Five out of six children have shown an improvement in their vision (average increase of 10 letters), including those who had previously failed to comply with conventional occlusion.

CONCLUSIONS

Improvements in vision were demonstrable within a short period of time, in some children after 1 h of treatment. This system is an exciting and promising application of VR technology as a new treatment for amblyopia.

Identification of the growth arrest and DNA damage protein GADD34 in the normal human heart and demonstration of alterations in expression following myocardial ischaemia

Growth arrest and DNA damage protein 34 (GADD34) is a multifunctional protein upregulated in response to cellular stress and is believed to mediate DNA repair and restore protein synthesis. In the present study we have examined GADD34 immunoreactivity in human myocardial tissue at defined survival times following cardiac arrest and determined alterations in expression following ischaemia. In the normal human heart, GADD34 immunoreactivity was generally intense and present within most cells. GADD34 immunoreactivity was downregulated in tissue displaying ischaemic damage and remained intense in adjacent non-infarcted tissue. Unlike brain, GADD34 was not found to be upregulated in the peri-infarct zone. Cells displaying apoptotic changes were located in regions displaying reduced GADD34 immunoreactivity. In the brain, it is thought that GADD34 supports re-initiation of protein synthesis following ischaemia. Similarly, GADD34 may perform important functions in cardiac tissue in response to ischaemia.

Feline B7.1 and B7.2 proteins produced from swinepox virus vectors are natively processed and biologically active: potential for use as nonchemical adjuvants

Costimulatory ligands, B7.1 and B7.2, have been incorporated into viral and DNA vectors as potential nonchemical adjuvants to enhance CTL and humoral immune responses against viral pathogens. In addition, soluble B7 proteins, minus their transmembrane and cytoplasmic domains, have been shown to block the down regulation of T-cell activation through blockade of B7/CTLA-4 interactions in mouse tumor models. Recently, we developed swinepox virus (SPV) vectors for delivery of feline leukemia antigens for vaccine use in cats [Winslow, B.J., Cochran, M.D., Holzenburg, A., Sun, J., Junker, D.E., Collisson, E.W., 2003. Replication and expression of a swinepox virus vector delivering feline leukemia virus Gag and Env to cell lines of swine and feline origin. Virus Res. 98, 1-15]. To explore the use of feline B7.1 and B7.2 ligands as nonchemical adjuvants, SPV vectors containing full-length feline B7.1 and B7.2 ligands were constructed and analyzed. Full-length feline B7.1 and B7.2 produced from SPV vectors were natively processed and costimulated Jurkat cells to produce IL-2, in vitro. In addition, we explored the feasibility of utilizing SPV as a novel expression vector to produce soluble forms of feline B7.1 (sB7.1) and B7.2 (sB7.2) in tissue culture. The transmembrane and cytoplasmic regions of the B7.1 and B7.2 genes were replaced with a poly-histidine tag and purified via a two-step chromatography procedure. Receptor binding and costimulation activity was measured. Although feline sB7.1-his and sB7.2-his proteins bound to the human homolog receptors, CTLA-4 and CD28, both soluble ligands possessed greater affinity for CTLA-4, compared to CD28. However, both retained the ability to partially block CD28-mediated costimulation in vitro. Results from these studies establish the use of SPV as a mammalian expression vector and suggest that full-length-vectored and purified soluble feline B7 ligands may be valuable, nonchemical immune-modulators.

A regulatory variant of the human tryptophan hydroxylase-2 gene biases amygdala reactivity

Recent studies have indicated that a newly identified second isoform of the tryptophan hydroxylase gene (TPH2) is preferentially involved in the rate-limiting synthesis of neuronal serotonin. Genetic variation in the human TPH2 gene (hTPH2) has been associated with altered in vitro enzyme activity as well as increased risk for mood disorders. Here, we provide the first in vivo evidence that a relatively frequent regulatory variant (G(-844)T) of hTPH2 biases the reactivity of the amygdala, a neural structure critical in the generation and regulation of emotional behaviors.

Assessment In Vitro of a Novel Therapeutic Strategy for Glioma, Combining Herpes Simplex Virus HSV1716-mediated Oncolysis with Gene Transfer and Targeted Radiotherapy

Genetically engineered herpes simplex virus ICP34.5 null mutants replicate only in dividing cells and have shown potential for the treatment of malignant disease, including glioma. Phase I trials have demonstrated the safety of these viruses in various clinical settings but it is envisaged that for full efficacy they will be used in combination with other therapeutic modalities. To enhance virus-induced tumour cytotoxicity, we have engineered an ICP34.5 null mutant (HSV1716) of HSV1 which expresses the noradrenaline transporter gene (NAT). This virus is designated HSV1716/NAT. We have shown previously that introduction of the NAT gene into a range of tumour cells, via plasmid-mediated transfection, conferred the capacity for active uptake of the radiopharmaceutical [131I]MIBG and resulted in dose-dependent toxicity. In this study, combination therapy utilising HSV1716/NAT and [131I]MIBG was assessed in vitro by the MTT assay. We demonstrate that the NAT gene, introduced by HSV1716/NAT into cultured glioma cells, was expressed 1 h after viral infection, enabling active uptake of [131I]MIBG. The combination of viral oncolysis and induced radiopharmaceutical uptake resulted in significantly enhanced cytotoxicity compared to either agent alone and the response was dose- and time-dependent. These studies show that the combination of oncolytic HSV therapy with targeted radiotherapy has the potential for effective tumour cell kill and warrants further investigation as a treatment for malignant glioma.

HSV1716 injection into the brain adjacent to tumour following surgical resection of high-grade glioma: safety data and long-term survival

Following standard treatment, the prognosis remains poor in patients with high-grade glioma and new therapies are urgently required. Herpes simplex virus 1716 (HSV1716) is an ICP34.5 null mutant that is selectively replication competent and shown to be safe and to replicate following injection into high-grade glioma. We demonstrate that following surgical resection, HSV1716 is safe when injected into the brain adjacent to excised tumour. In all, 12 patients with recurrent or newly diagnosed high-grade glioma underwent maximal resection of the tumour. HSV1716 was injected into eight to 10 sites around the resulting tumour cavity with the intent of infecting residual tumour cells. As clinically indicated, patients proceeded to further radiotherapy or chemotherapy. There has been no clinical evidence of toxicity associated with the administration of HSV1716. Longitudinal follow-up has allowed the assessment of overall survival compared to that of similar patients not treated with HSV1716. Three patients remain alive and clinically stable at 15, 18 and 22 months postsurgery and HSV1716 injection. Remarkably, the first patient in the trial, who had extensive recurrent disease preprocedure, is alive at 22 months since injection of HSV1716 and 29 months since first diagnosis. Imaging has demonstrated a reduction of residual tumour over the 22-month period despite no further medical intervention since the surgery and HSV1716 injection. In this study, we demonstrate that on the basis of clinical observations, there has been no toxicity following the administration of HSV1716 into the resection cavity rim in patients with high-grade glioma. The survival and imaging data, in addition to the lack of toxicity, give us confidence to proceed to a clinical trial to demonstrate efficacy of HSV1716 in glioma patients.

Eyeblink conditioning deficits indicate timing and cerebellar abnormalities in schizophrenia

Accumulating evidence indicates that individuals with schizophrenia manifest abnormalities in structures (cerebellum and basal ganglia) and neurotransmitter systems (dopamine) linked to internal-timing processes. A single-cue tone delay eyeblink conditioning paradigm comprised of 100 learning and 50 extinction trials was used to examine cerebellar timing circuits in 13 medicated patients with schizophrenia and 13 age- and sex-matched controls. Patients with schizophrenia showed impaired learning of the conditioned response compared to controls and also greater within-subject variability in the timing of their responses. These findings are consistent with models of schizophrenia in which timing deficits underlie information-processing abnormalities and clinical features of the disorder.

Up-regulation of a growth arrest and DNA damage protein (GADD34) in the ischaemic human brain: implications for protein synthesis regulation and DNA repair

GADD34 is a growth arrest and DNA damage inducible gene up-regulated in response to DNA damage, cell cycle arrest and apoptosis. It is thought that GADD34 may play a crucial role in cell survival in ischaemia. GADD34 expression was assessed immunohistochemically in post-mortem human hippocampal tissue obtained from patients surviving for defined periods (0-24 h; 24 h-7 days) after a cardiac arrest and in age-matched control subjects. In control brain, cytoplasm staining in GADD34 immunopositive cells was faint but present throughout the hippocampus and cortex. There was minimal change in GADD34 expression in the group surviving 0-24 h after cardiac arrest. However GADD34 immunostaining was markedly increased in selectively vulnerable regions in the 24 h-7 day survival group. Increased GADD34 staining was present in ischaemic neurones and in some morphologically normal neurones after cardiac arrest. Extensive ischaemic damage was found to correlate with elevated GADD34 immunostaining in the CA1 layer of the hippocampus (**P < 0.0016). In addition, GADD34 was found to colocalize with proliferating cell nuclear antigen in some neurones. The up-regulation of GADD34 in response to global ischaemia in the human brain plus its influence on protein synthesis and DNA repair suggests that this protein may have the potential to influence cell survival.

Selection and validation of differentially expressed genes in head and neck cancer

We applied a robust combinatorial (multi-test) approach to microarray data to identify genes consistently up- or down-regulated in head and neck squamous cell carcinoma (HNSCC). RNA was extracted from 22 paired samples of HNSCC and normal tissue from the same donors and hybridized to the Affymetrix U95A chip. Forty-two differentially expressed probe sets (representing 38 genes and one expressed sequence tag) satisfied all statistical tests of significance and were selected for further validation. Selected probe sets were validated by hierarchical clustering, multiple probe set concordance, and target-subunit agreement. In addition, real-time PCR analysis of 8 representative (randomly selected from 38) genes performed on both microarray-tested and independently obtained samples correlated well with the microarray data. The genes identified and validated by this method were in comparatively good agreement with other rigorous HNSCC microarray studies. From this study, we conclude that combinatorial analysis of microarray data is a promising technique for identifying differentially expressed genes with few false positives.

HSV Growth, Preparation, and Assay

Whether herpes simplex virus (HSV) is viewed as a pathogen or as a model eukaryotic system, it is virtually certain that any experimental work will require the virus to be grown and assayed. The following chapter is therefore seen as the fundamental first step before embarking on more intellectually and technically challenging technology. Its importance should not however be underestimated. It never fails to surprize us that people who describe themselves as virologists have little understanding of the basic requirements needed to attain a contamination-free, high-titer, low particle:plaque-forming units (PFU) ratio, genetically pure virus stock.

A model of venous return while utilizing vacuum assist during cardiopulmonary bypass

In order for vacuum-assisted venous return (VAVR) to be used safely and efficiently during cardiopulmonary bypass (CPB), a full understanding of venous return is necessary. The focus of this work was to use the concepts of energy conservation and viscous energy dissipation in the development of a theoretical model of venous return utilizing vacuum assist. The effectiveness and accuracy of this model has been verified through in vitro laboratory investigations and statistical analysis. Although VAVR can provide higher flows through smaller venous cannula, vacuum assist may lead to increased levels of wall shear stress as shown in this work. The clinical implications of VAVR have yet to be investigated, but may lead to an exacerbation of the detrimental effects of CPB during cardiac surgery.

HSV1716 persistence in primary human glioma cells in vitro

HSV1716 is a selectively replication competent mutant of herpes simplex virus which is in trial in glioma patients. We have demonstrated that HSV1716 is non-toxic when delivered into tumour or into brain adjacent to tumour, yet replicates within tumour cells. Tumour tissue, from one patient treated 2.5 years previously with intra-tumoural HSV1716, was put into culture. The cultured cells were shown to be glial in origin with no evidence of residual HSV1716. These cells were subsequently infected at a MOI of 0.1 with either HSV1716 or wild-type HSV17(+). The HSV17(+) infected cells were completely rounded up or lysed within 72 h. Although the cells supported HSV1716 replication and also became rounded or lysed, a proportion (approximately 20%) remained viable. These cells continued to divide and shed low levels of HSV1716 up to 31 days after infection when there was evidence of rapid virus replication resulting in complete cell lysis. These data demonstrate that HSV1716 can 'persist' in human glioma cells at least in vitro and gives credence to the possibility that in tumours in vivo a similar phenomenon may take place. If this were the case, then HSV1716 has the potential to kill tumour cells over a prolonged period of time.

Specific expression of the cell cycle regulation proteins, GADD34 and PCNA, in the peri-infarct zone after focal cerebral ischaemia in the rat

Cell cycle proteins play key roles in cell survival or death under pathological conditions. Expression of growth arrest and DNA damage-inducible protein, GADD34 and proliferating cell nuclear antigen (PCNA) have been investigated in the core and peri-infarct zone at 2 and 24 h after middle cerebral artery occlusion (MCAO). At these times after MCAO, numerous GADD34-positive cells were present, particularly in the peri-infarct zone (e.g. 24 +/- 4 and 52 +/- 6 immunopositive cells/0.25 mm2 at 2 and 24 h, respectively, in cortex). PCNA-immunopositive cells were barely detectable in the peri-infarct zone at 2 h; however, numerous PCNA-immunopositive cells were present in this zone by 24 h (0.7 +/- 0.3 and 10.6 +/- 1.5 immunopositive cells/0.25 mm2, respectively) as well as in the adjacent cortex and in the contralateral cingulate cortex. Most GADD34-immunopositive cells coexpressed the neuronal marker Neu-N with a smaller number coexpressing the microglial marker, Mrf-1. Evidence of morphologically 'abnormal' and 'normal' GADD34 immunopositive neurons was found within the peri-infarct zone. The majority of PCNA immunopositive cells were Mrf-1 positive with a smaller number Neu-N positive. Double-labelling revealed colocalization of GADD34 and PCNA in some cells within the peri-infarct zone and in the ependymal cells lining the ventricles. The presence of GADD34 and PCNA in a key anatomical location pertinent to the evolving ischaemic lesion indicates that GADD34, either alone or in combination with PCNA, has the potential to influence cell survival in ischaemically compromised tissue.

Scaling laws in NMR scattering via dipolar fields

Breaking translational symmetry in magnetostatics imparts a scale dependence that is commonly investigated in physics (W. Warren et al., 1993, Science 262, 2005-2008). An interesting and important example arises in nuclear magnetic resonance studies involving the dipolar mean field of adjacent nuclear spins where the scattering (transfer of spatial spin gratings) via intermolecular macroscopic fields carries a signature of the local spatial distribution of the spin density. For arbitrary geometry, the inverse problem of extracting this spin distribution from experiments is intractable. Here we point out a simple, universal crossover in the scaling behavior at the sample's characteristic length scale, xi, of the species fluctuations in the sample along the measurement direction. This behavior is observed experimentally in an oil-water emulsion, an important representation of complex, heterogeneous, soft matter.

Relaxation of postoperative astigmatism after lens implantation through a 6.25 mm scleral wound in children

PURPOSE

To investigate the evolution of postoperative astigmatism in children having cataract extraction with intraocular lens (IOL) implantation through a 6.25 mm superior scleral tunnel wound.

SETTING

A university clinical practice.

METHODS

A retrospective chart review of all pediatric patients having cataract extraction and IOL implantation in the practice of 1 surgeon from 1995 to 2000 was performed. Statistical comparisons were performed using the Student t test for nonpaired data.

RESULTS

Ten eyes of 9 children were included. Six cataracts were due to corneal or corneoscleral lacerations, 3 were idiopathic, and 1 occurred after blunt trauma. Eight eyes could not be refracted preoperatively because of mature cataract. The mean cylindrical correction of all refractions performed 1 to 15 days after surgery (n = 6) was 6.71 diopters (D) +/- 1.63 (SD); of those performed at 16 to 30 days (n = 6), 2.71 +/- 2.09 D; and of those performed at 31 to 45 days (n = 7), 1.93 +/- 1.48 D. The mean spherical equivalent of the final (dispensed) refraction was -0.21 +/- 1.79 D; the mean cylindrical correction of this refraction was 1.13 +/- 0.79 D. The difference between the cylindrical correction of the final prescription and the corneal astigmatism in fellow eyes was not statistically significant (P =.29).

CONCLUSIONS

Relaxation of large amounts of suture-induced astigmatism occurs in children having cataract extraction. Surgeons should not hesitate to secure scleral wounds meticulously in children for fear of a permanent undesirable refractive outcome.

Cutting edge: positive selection induced by a self-peptide with TCR antagonist activity

Antagonist-like engagement of the TCR has been proposed to induce T cell selection in the thymus. However, no natural TCR ligand with TCR antagonist activity is presently known. Using a combination of bioinformatics and functional testing we identified the first self-peptide that can both deliver antagonist-like signals and promote T cell selection in the thymus. The peptide is presented by appropriate MHC class I molecules in vivo. Thus, endogenous antagonist peptides exist and may be involved in TCR repertoire selection.

Definitive identification of mammalian 5-hydroxymethyluracil DNA N-glycosylase activity as SMUG1

Purification from calf thymus of a DNA N-glycosylase activity (HMUDG) that released 5-hydroxymethyluracil (5hmUra) from the DNA of Bacillus subtilis phage SPO1 was undertaken. Analysis of the most purified fraction by SDS-polyacrylamide gel electrophoresis revealed a multiplicity of protein species making it impossible to identify HMUDG by inspection. Therefore, we renatured the enzyme after SDS-polyacrylamide gel electrophoresis and assayed slices of the gel for DNA N-glycosylase activity directed against 5hmUra. Maximum enzymatic activity was identified between molecular mass markers 30 and 34 kDa. Protein was extracted from gel slices and subjected to tryptic digestion and analysis by mass spectrometry. Analysis revealed the presence of 11 peptides that were homologous or identical to the sequence of the recently characterized human single-stranded monofunctional uracil DNA N-glycosylase (hSMUG1). The cDNA of hSMUG1 was isolated and expressed as a recombinant glutathione S-transferase fusion protein that was shown to release 5hmUra with 20x the specific activity of the most purified bovine fraction. We conclude that hSMUG1 and HMUDG are the same protein.