Bivalent engagement of endothelial surface antigens is critical to prolonged surface targeting and protein delivery in vivo.

Targeted drug delivery to the endothelium has the potential to generate localized therapeutic effects at the blood-tissue interface. For some therapeutic cargoes, it is essential to maintain contact with the bloodstream to exert protective effects. The pharmacokinetics (PK) of endothelial surface-targeted affinity ligands and biotherapeutic cargo remain a largely unexplored area, despite obvious translational implications for this strategy. To bridge this gap, we site-specifically radiolabeled mono- (scFv) and bivalent (mAb) affinity ligands specific for the endothelial cell adhesion molecules, PECAM-1 (CD31) and ICAM-1 (CD54). Radiotracing revealed similar lung biodistribution at 30 minutes post-injection (79.3% ± 4.2% vs 80.4% ± 10.6% ID/g for αICAM and 58.9% ± 3.6% ID/g vs. 47.7% ± 5.8% ID/g for αPECAM mAb vs. scFv), but marked differences in organ residence time, with antibodies demonstrating an order of magnitude greater area under the lung concentration vs. time curve (AUCinf 1698 ± 352 vs. 53.3 ± 7.9 ID/g*hrs for αICAM and 1023 ± 507 vs. 114 ± 37 ID/g*hrs for αPECAM mAb vs scFv). A physiologically based pharmacokinetic model, fit to and validated using these data, indicated contributions from both superior binding characteristics and prolonged circulation time supporting multiple binding-detachment cycles. We tested the ability of each affinity ligand to deliver a prototypical surface cargo, thrombomodulin (TM), using one-to-one protein conjugates. Bivalent mAb-TM was superior to monovalent scFv-TM in both pulmonary targeting and lung residence time (AUCinf 141 ± 3.2 vs 12.4 ± 4.2 ID/g*hrs for ICAM and 188 ± 90 vs 34.7 ± 19.9 ID/g*hrs for PECAM), despite having similar blood PK, indicating that binding strength is more important parameter than the kinetics of binding. To maximize bivalent target engagement, we synthesized an oriented, end-to-end anti-ICAM mAb-TM conjugate and found that this therapeutic had the best lung residence time (AUCinf 253 ± 18 ID/g*hrs) of all TM modalities. These observations have implications not only for the delivery of TM, but also potentially all therapeutics targeted to the endothelial surface.

A randomised study comparing the effectiveness of acupuncture or morphine versus the combination for the relief of dyspnoea in patients with advanced non-small cell lung cancer and mesothelioma.

BACKGROUND: Dyspnoea is one of the commonest symptoms of lung cancer. Opioids can reduce dyspnoea. This study investigates acupuncture for relief of breathlessness in lung cancer. METHODS: We performed a single-centre, randomised phase II study of 173 patients with non-small cell lung cancer or mesothelioma with dyspnoea score of ≥4 on visual analogue scale (VAS). Randomisation was to acupuncture alone (A), morphine alone (M) or both (AM). Acupuncture was administered at upper sternal, thoracic paravertebral, trapezius trigger points and LI4. Manubrial semi-permanent acupuncture studs were inserted and massaged when symptomatic. Arm A patients received rescue morphine. Primary end-point was proportion of patients achieving ≥1.5 improvement in VAS dyspnoea at 4 h. Measurements continued to day 14 and included VAS relaxation, line analogue rating (Lar) anxiety, hospital anxiety and depression and European Organisation for Research and Treatment of Cancer quality-of-life scores. RESULTS: Dyspnoea VAS improved ≥1.5 in 74%, 60% and 66% of arms A, M and AM, respectively, and was maintained in 45% at 2 weeks. There was no statistically significant difference between arms. VAS relaxation improved in arms A (1.06 points) and AM (1.48 points) compared to arm M (-0.19 points, p<0.001). At 7 d, the Lar anxiety score improved in arm A (1.5 points), arm AM (1.2 points) and arm M (no change, p=0.003). Fewer patients received at least one morphine dose in arm A compared with arm M or AM (21% versus 87% versus 87%, respectively, p<0.001). CONCLUSIONS: A, M and AM were effective in relieving dyspnoea. Acupuncture relieved anxiety and was morphine sparing, providing an alternative to morphine.

A phase II study of ¹8F-fluorodeoxyglucose PET-CT in non-small cell lung cancer patients receiving erlotinib (Tarceva); objective and symptomatic responses at 6 and 12 weeks.

BACKGROUND: The aim of this study was to assess if (18)F-fluorodeoxyglucose (FDG) Positron Emission Tomography (PET)-CT scanning could minimise the time non-responding patients were exposed to erlotinib (Tarceva). METHODS: Patients were selected for clinical factors that would predict response to erlotinib. A FDG PET-CT and diagnostic contrast-enhanced (traditional) CT scan were carried out at baseline, and then a FDG PET-CT at 6 weeks and a traditional CT at 12 weeks were repeated. The primary end-point was rate of early progression in patients after 6 weeks, of which a minimum 12 out of 35 were required to make the study worthwhile. The responses at 6 (PET-CT) and 12 weeks (traditional CT) were compared and correlated with symptomatic response at both these time points. RESULTS: Forty seven patients were recruited with 38 and 33 patients assessable by FDG PET-CT at 6 weeks and traditional CT at 12weeks, respectively. There was good correlation between Partial response (PR) at both time points and all 10 patients who had a PR at 12 weeks had a PR at 6 weeks. Of the 13 patients with progressive disease (PD) at 12 weeks, seven had PD at 6 weeks and could have had their treatment stopped early. No evaluable patient with stable disease (SD) (8/38) or PD (9/38) on FDG PET-CT at 6 weeks went on to have a later response. Symptomatic response at 6 or 12 weeks did not correlate well with objective response on scanning at either time point. CONCLUSIONS: The primary end-point of this study was met as >12 (15/38) patients could have stopped treatment early on the basis of the FDG PET-CT scan result. A FDG PET-CT evaluable response of SD or PD at 6 weeks does predict future lack of response. No correlation was found between response and symptomatic response at either 6 or 12 weeks.

Thrombin-inhibiting perfluorocarbon nanoparticles provide a novel strategy for the treatment and magnetic resonance imaging of acute thrombosis.

BACKGROUND: As a regulator of the penultimate step in the coagulation cascade, thrombin represents a principal target of direct and specific anticoagulants. OBJECTIVE: A potent thrombin inhibitor complexed with a colloidal nanoparticle was devised as a first-in-class anticoagulant with prolonged and highly localized therapeutic impact conferred by its multivalent thrombin-absorbing particle surface. METHODS: PPACK (Phe[D]-Pro-Arg-Chloromethylketone) was secured covalently to the surface of perfluorocarbon-core nanoparticle structures. PPACK and PPACK nanoparticle inhibition of thrombin were assessed in vitro via thrombin activity against a chromogenic substrate. In vivo antithrombotic activity of PPACK, heparin, non-functionalized nanoparticles and PPACK nanoparticles was assessed through intravenous (i.v.) administration prior to acute photochemical injury of the common carotid artery. Perfluorocarbon particle retention in extracted carotid arteries from injured mice was assessed via (19) F magnetic resonance spectroscopy (MRS) and imaging (MRI) at 11.7 T. Activated partial thromboplastin time (APTT) measurements determined the systemic effects of the PPACK nanoparticles at various times after injection. RESULTS: An optical assay verified that PPACK nanoparticles exceeded PPACK's intrinsic activity against thrombin. Application of an in vivo acute arterial thrombosis model demonstrated that PPACK nanoparticles outperformed both heparin (P=0.001) and uncomplexed PPACK (P = 0.0006) in inhibiting thrombosis. (19) F MRS confirmed that PPACK nanoparticles specifically bound to sites of acute thrombotic injury. APTT normalized within 20 min of PPACK nanoparticles injection. CONCLUSIONS: PPACK nanoparticles present thrombin-inhibiting surfaces at sites of acutely forming thrombi that continue to manifest local clot inhibition even as systemic effects rapidly diminish and thus represent a new platform for localized control of acute thrombosis.

Histology classification is not a predictor of clinical outcomes in advanced non-small cell lung cancer (NSCLC) treated with vinorelbine or gemcitabine combinations.

BACKGROUND: Until recently, histology has not been clearly or consistently described in the literature as a prognostic or predictive variable in advanced NSCLC studies. We have categorised patients treated with vinorelbine and gemcitabine based first line chemotherapy regimes for advanced NSCLC as either squamous or non-squamous, and also as either adenocarcinoma and non-adenocarcinoma, and compared outcome. MATERIAL AND METHODS: 420 patients treated with platinum/gemcitabine, platinum/vinorelbine or single agent gemcitabine or vinorelbine as first line chemotherapy for advanced NSCLC were identified. The influence of pathology on progression free survival (PFS) and overall survival (OS) has been investigated by means of a Cox regression analysis. Hazard ratios with 95% CIs have been given for each pathological type after adjusting for the effects of age, gender, stage (III vs. IV), PS (0/1 vs. 2/3) and treatment type (platinum doublet vs. single agent). RESULTS: Neither univariate nor multivariate analysis suggested that there was a significant difference in the response rates for adenocarcinoma vs. non-adenocarcinoma or between squamous and non-squamous pathology. There was no difference in PFS between adenocarcinoma and non-adenocarcinoma pathologies until 8 months (p = 0.98), and there was a statistically significant advantage in PFS for squamous vs. non-squamous pathologies (p = 0.04). Using multivariate Cox regression analysis to adjust for the effects of age, gender, stage, PS, and treatment type, the pathology subtype was not significant. There was no difference in OS in any group. CONCLUSIONS: These results suggest that histology may not be considered as a predictor of clinical outcome using these drugs.

Treatment options for small cell lung cancer - do we have more choice?

Small cell lung cancer (SCLC) is a significant health problem worldwide because of its high propensity for relapse. This review discusses existing and future therapies for the treatment of SCLC.

The role of nanostructure in the wetting behavior of mixed-monolayer-protected metal nanoparticles.

Self-assembled monolayer-protected nanoparticles are promising candidates for applications, such as sensing and drug delivery, in which the molecular ligands' interactions with the surrounding environment play a crucial role. We recently showed that, when gold nanoparticles are coated with a binary mixture of immiscible ligands, ordered ribbon-like domains of alternating composition spontaneously form and that their width is comparable with the size of a single solvent molecule. It is usually assumed that nanoparticles' solubility depends solely on the core size and on the molecular composition of the ligand shell. Here, we show that this is not always the case. We find that the ligand shell morphology affects the solubility of these nanoparticles almost as much as the molecular composition. A possible explanation is offered through a molecular dynamics analysis of the surface energy of monolayers differing only in their domain structure. We find that the surface free energy of such model systems can vary significantly as a function of ordering, even at fixed composition. This combined experimental and theoretical study provides a unique insight into wetting phenomena at the nano- and subnanometer scale.

Area under the curve as a measure of discounting.

We describe a novel approach to the measurement of discounting based on calculating the area under the empirical discounting function. This approach avoids some of the problems associated with measures based on estimates of the parameters of theoretical discounting functions. The area measure may be easily calculated for both individual and group data collected using any of a variety of current delay and probability discounting procedures. The present approach is not intended as a substitute for theoretical discounting models. It is useful, however, to have a simple, univariate measure of discounting that is not tied to any specific theoretical framework.

The effects of eye and limb movements on working memory.

Three experiments examined the role of eye and limb movements in the maintenance of information in spatial working memory. In Experiment 1, reflexive saccades interfered with memory span for spatial locations but did not interfere with memory span for letters. In Experiment 2, three different types of eye movements (reflexive saccades, pro-saccades, and anti-saccades) interfered with working memory to the same extent. In all three cases, spatial working memory was much more affected than verbal working memory. The results of these two experiments suggest that eye movements interfere with spatial working memory primarily by disrupting processes localised in the visuospatial sketchpad. In Experiment 3, limb movements performed while maintaining fixation produced as much interference with spatial working memory as reflexive saccades. These results suggest that the interference produced by eye movements is not the result of their visual consequences. Rather, all spatially directed movements appear to have similar effects on visuospatial working memory.

Age and individual differences in visuospatial processing speed: testing the magnification hypothesis.

Forty young adults and 40 older adults performed seven visuospatial information processing tasks. Factor analyses of the response times (RTs) yielded a single principal component with a similar composition in both age samples. For both samples, regressing the mean RTs of fast and slow subgroups for the seven tasks (18 conditions) on the corresponding mean RTs for their age group accounted for 99% of the variance. Taken together, these findings suggest that individual differences in processing time were largely task independent. The magnification hypothesis, a simple mathematical model of the interaction between age and ability, is presented. This model correctly predicts the finding that in both the young and the older adult groups, individual differences increased systematically with task difficulty. The magnification hypothesis also explains the regression parameters describing individual differences among young adults and predicts correctly that equivalent parameters describe individual differences among older adults. According to the magnification hypothesis, the RTs of slower individuals are more affected by aging than those of faster individuals, and slower individuals may be more at risk with respect to other biological insults (e.g., changes in health status) as well.

Behavioral evidence for brain-based ability factors in visuospatial information processing.

The present study examined possible parallels between the structure of human visuospatial abilities and the organization of the neural systems. Forty-eight participants were tested on seven speeded visuospatial tasks. Three of these tasks were constructed so as to rely primarily on known ventral stream functions and four were constructed so as to rely primarily on known dorsal stream functions. Both sets of tasks spanned approximately the same range of difficulty as indexed by both the speed and accuracy of decision making. Factor analysis of response times on the seven tasks revealed only two significant factors. The putative ventral stream tasks all loaded heavily on one factor (mean loading=0.843) but only weakly on the other factor (mean loading=0.222); the putative dorsal stream tasks showed the opposite pattern in that they all loaded heavily on the second factor (mean loading=0.828) but only weakly on the first factor (mean loading=0.229). These findings are consistent with the hypothesis that human visuospatial abilities can be classified using categories based on the specializations of underlying neural structures and systems.

Converging evidence that visuospatial cognition is more age-sensitive than verbal cognition.

In 3 separate experiments, the same samples of young and older adults were tested on verbal and visuospatial processing speed tasks, verbal and visuospatial working memory tasks, and verbal and visuospatial paired-associates learning tasks. In Experiment 1, older adults were generally slower than young adults on all speeded tasks, but age-related slowing was much more pronounced on visuospatial tasks than on verbal tasks. In Experiment 2, older adults showed smaller memory spans than young adults in general, but memory for locations showed a greater age difference than memory for letters. In Experiment 3, older adults had greater difficulty learning novel information than young adults overall, but older adults showed greater deficits learning visuospatial than verbal information. Taken together, the differential deficits observed on both speeded and unspeeded tasks strongly suggest that visuospatial cognition is generally more affected by aging than verbal cognition.

Selective interference with verbal and spatial working memory in young and older adults.

Young and older adults were administered digit and location memory span tasks with and without verbal and spatial secondary tasks. Age differences were greater in location span than in digit span; however, there were no age differences in either the magnitude or pattern of effects of secondary tasks. There were also no age differences in the effects of secondary tasks on a combined (digit and location) task. On the digit and location span tasks, both young and older adults showed only domain-specific interference: naming colors selectively interfered with memory for digits, leaving memory for locations unaffected; pointing to matching colors selectively interfered with memory for locations, leaving memory for digits unimpaired. The results of the present study suggest a greater age deficit in spatial working memory than in verbal working memory, but provide no evidence of an age deficit in susceptibility to interference by secondary tasks in either domain.

Amount of reward has opposite effects on the discounting of delayed and probabilistic outcomes.

Previous research has shown that the value of large future rewards is discounted less steeply than is the value of small future rewards. These experiments extended this line of research to probabilistic rewards. Two experiments replicated the standard findings for delayed rewards but demonstrated that amount has an opposite effect on the discounting of probabilistic rewards. That is, large probabilistic amounts were discounted at the same or higher rates than small amounts. Although amount had opposite effects on the discounting of delayed and probabilistic rewards, nevertheless, the same form of mathematical function accurately described discounting of both types of reward. The findings suggest that fundamentally similar, but not identical, processes are involved in decision making regarding delayed and probabilistic rewards. The implications of these findings for impulsivity and self-control are discussed.

Individual and developmental differences in working memory across the life span.

The effects of secondary tasks on verbal and spatial working memory were examined in multiple child, young adult, and older adult samples. Although memory span increased with age in the child samples and decreased with age in the adult samples, there was little evidence of systematic change in the magnitude of interference effects. Surprisingly, individuals who had larger memory spans when there was no secondary task showed greater interference effects than their age-mates. These findings are inconsistent with the hypothesis that age and individual differences in working memory are due to differences in the ability to inhibit irrelevant information, at least as this hypothesis is currently formulated. Moreover, our results suggest that different mechanisms underlie developmental and individual differences in susceptibility to interference across the life span. A model is proposed in which memory span and processing speed both increase with development but are relatively independent abilities within age groups.

Discounting of delayed rewards across the life span: age differences in individual discounting functions.

The present effort addressed both the issue of the generality of choice models and the issue of possible qualitative developmental change in temporal discounting by examining behavior at the individual level across the life span. Data from individual children, young adults, and older adults who participated in two previous studies were analyzed [Green, L., Fry, A.F., Myerson, J., 1994. Discounting of delayed rewards: a life-span comparison. Psychol. Sci. 5, 33-36; Green, L., Myerson, J., Lichtman, D., Rosen, S., Fry, A., 1996. Temporal discounting in choice between delayed rewards: the role of age and income. Psychol. Aging 11, 79-84]. At all ages, a hyperbola-like function originally proposed by Green et al. (1994) based on group data, provided the best description of individual discounting functions. Two developmental trends were observed. The rate at which individuals discounted the value of delayed rewards decreased with age, and there was a systematic change in the shape of the discounting function. Each of these trends was reflected in a separate parameter of the model. The fact that the same mathematical model described the behavior of individuals of different ages suggests that age and individual differences in the discounting of delayed rewards are primarily quantitative in nature and reflect variations on fundamentally similar choice processes.

Cerebellar contribution to linguistic processing efficiency revealed by focal damage.

The cerebellum's role in cognitive skills was examined in a child (L.C.) with focal injury to the left cerebellum. Initial symptoms included aphasia and dysarthria. At 3 and 9 months post-injury, clinical neuropsychological tests revealed persistent psychomotor slowing as well as deficits in executive functions. Further cognitive testing at 13 and 16 months post-injury demonstrated that L.C. processed information from both the linguistic and nonlinguistic domains more slowly than age-, grade- and sex-matched controls. Notably, her linguistic processing was more than twice as slow as that of her peers, whereas her nonlinguistic processing was only approximately 20% slower. Within each domain the degree of cognitive slowing was approximately the same across diverse tasks. These results are consistent with the hypothesis of a cerebellar contribution to cognitive processing, particularly the processing of linguistic information.

General slowing of lexical and nonlexical information processing in dementia of the Alzheimer type.

Individuals with very mild and mild dementia of the Alzheimer type (DAT) and age-matched controls performed three lexical and three nonlexical speeded information-processing tasks. The DAT group was slower than the control group on all six tasks. As predicted by general slowing (Nebes & Brady, 1992), most main effects of task condition were accompanied by Group × Condition interactions. That is, as task complexity increased, the response times (RTs) of the DAT group increased more than the RTs of the control group. Multitask regression analyses confirmed the existence of general slowing in DAT, such that the DAT group took approximately 1.8 times as long to process information as the controls on all six tasks. Importantly, lexical and nonlexical processing speed were equivalently affected by DAT. This pattern was observed both in very mild and mild DAT, although the degree of general slowing increased with the severity of the dementia.

Rate of temporal discounting decreases with amount of reward.

The present, subjective value of a delayed reward is a decreasing function of the duration of the delay. This phenomenon is termed temporal discounting. To determine whether the amount of the reward influences the rate of temporal discounting, we had subjects choose between immediate and delayed hypothetical rewards of different amounts ($100, $2,000, $25,000, and $100,000 delayed rewards). As predicted by psychological models of the choice process, hyperbolic functions described the decrease in the subjective value of the delayed reward as the time until its receipt was increased (R2s from .86 to .99). Moreover, hyperbolic functions consistently provided more accurate descriptions of the data than did exponential functions predicted by an economic model of discounted utility. Rate of discounting decreased in a negatively accelerated fashion as the amount of the delayed reward increased, leveling off by approximately $25,000. These findings are interpreted in the context of different psychological models of choice, and implications for procedures to enhance self-control are discussed.