Kinetic analysis of novel mono- and multivalent VHH-fragments and their application for molecular imaging of brain tumours

BACKGROUND AND PURPOSE

The overexpression of epidermal growth factor receptor (EGFR) and its mutated variant EGFRvIII occurs in 50% of glioblastoma multiforme. We developed antibody fragments against EGFR/EGFRvIII for molecular imaging and/or therapeutic targeting applications.

EXPERIMENTAL APPROACH

An anti-EGFR/EGFRvIII llama single-domain antibody (EG(2)) and two higher valency format constructs, bivalent EG(2)-hFc and pentavalent V2C-EG(2) sdAbs, were analysed in vitro for their binding affinities using surface plasmon resonance and cell binding studies, and in vivo using pharmacokinetic, biodistribution, optical imaging and fluorescent microscopy studies.

KEY RESULTS

Kinetic binding analyses by surface plasmon resonance revealed intrinsic affinities of 55 nM and 97 nM for the monovalent EG(2) to immobilized extracellular domains of EGFR and EGFRvIII, respectively, and a 10- to 600-fold increases in apparent affinities for the multivalent binders, V2C-EG(2) and EG(2)-hFc, respectively. In vivo pharmacokinetic and biodistribution studies in mice revealed plasma half-lives for EG(2), V2C-EG(2) and EG(2)-hFc of 41 min, 80 min and 12.5 h, respectively, as well as a significantly higher retention of EG(2)-hFc compared to the other two constructs in EGFR/EGFRvIII-expressing orthotopic brain tumours, resulting in the highest signal in the tumour region in optical imaging studies. Time domain volumetric optical imaging fusion with high-resolution micro-computed tomography of microvascular brain network confirmed EG(2)-hFc selective accumulation/retention in anatomically defined tumour regions.

CONCLUSIONS

Single domain antibodies can be optimized for molecular imaging applications by methods that improve their apparent affinity and prolong plasma half-life and, at the same time, preserve their ability to penetrate tumour parenchyma.

Chronic prenatal ethanol exposure alters hippocampal GABAA receptors and impairs spatial learning in the guinea pig

Chronic prenatal ethanol exposure (CPEE) can injure the developing brain, and may lead to the fetal alcohol syndrome (FAS). Previous studies have demonstrated that CPEE upregulates gamma-aminobutyric acid type A (GABA(A)) receptor expression in the cerebral cortex, and decreases functional synaptic plasticity in the hippocampus, in the adult guinea pig. This study tested the hypothesis that CPEE increases GABA(A) receptor expression in the hippocampus of guinea pig offspring that exhibit cognitive deficits in a hippocampal-dependent spatial learning task. Timed, pregnant guinea pigs were treated with ethanol (4 g/kg maternal body weight per day), isocaloric-sucrose/pair-feeding, or water throughout gestation. GABA(A) receptor subunit protein expression in the hippocampus was measured at two development ages: near-term fetus and young adult. In young adult guinea pig offspring, CPEE increased spontaneous locomotor activity in the open-field and impaired task acquisition in the Morris water maze. CPEE did not change GABA(A) receptor subunit protein expression in the near-term fetal hippocampus, but increased expression of the beta2/3-subunit of the GABA(A) receptor in the hippocampus of young adult offspring. CPEE did not change either [(3)H]flunitrazepam binding or GABA potentiation of [(3)H]flunitrazepam binding, but decreased the efficacy of allopregnanolone potentiation of [(3)H]flunitrazepam binding, to hippocampal GABA(A) receptors in adult offspring. Correlational analysis revealed a relationship between increased spontaneous locomotor activity and growth restriction in the hippocampus induced by CPEE. Similarly, an inverse relationship was found between performance in the water maze and the efficacy of allopregnanolone potentiation of [(3)H]flunitrazepam binding in the hippocampus. These data suggest that alterations in hippocampal GABA(A) receptor expression and pharmacological properties contribute to hippocampal-related behavioral and cognitive deficits associated with CPEE.

Evaluation of brain tumor vessels specific contrast agents for glioblastoma imaging

A mouse model of glioblastoma multiforme was used to determine the accumulation of a targeted contrast agent in tumor vessels. The contrast agent, consisting of superparamagnetic iron oxide coated with dextran, was functionalized with an anti-insulin-like-growth-factor binding protein 7 (anti-IGFBP7) single domain antibody. The near infrared marker, Cy5.5, was also attached for an in vivo fluorescence study. A 9.4T magnetic resonance imaging (MRI) system was used for in vivo studies on days 10 and 11 following tumor inoculation. T(2) relaxation time was used to measure the accumulation of the contrast agent in the tumor. Changes in tumor to brain contrast because of active targeting were compared with a nontargeted contrast agent. Effective targeting was confirmed with near infrared measurements and fluorescent microscopic analysis. The results showed that there was a statistically significant (P < .01) difference in normalized T(2) between healthy brain and tumor tissue 10 min, 1 h, and 2 h point postinjection of the anti-IGFBP7 single domain antibody targeted and nontargeted iron oxide nanoparticles. A statistical difference remained in animals treated with targeted nanoparticles 24 h postinjection only. The MRI, near infrared imaging, and fluorescent microscopy studies showed corresponding spatial and temporal changes. We concluded that the developed anti-IGFBP7-iron oxide single domain antibody-targeted MRI contrast agent selectively binds to abnormal vessels within a glioblastoma. T(2)-weighted MRI and near infrared imaging are able to detect the targeting effects in brain tumors.

Molecular imaging of glioblastoma multiforme using anti-insulin-like growth factor-binding protein-7 single-domain antibodies

Background:

Insulin-like growth factor-binding protein 7 (IGFBP7) is an abundant, selective and accessible biomarker of glioblastoma multiforme (GBM) tumour vessels. In this study, an anti-IGFBP7 single-domain antibody (sdAb) was developed to target GBM vessels for molecular imaging applications.

Methods:

Human GBM was modelled in mice by intracranial implantation of U87MG.EGFRvIII cells. An anti-IGFBP7 sdAb, isolated from an immune llama library by panning, was assessed in vitro for its binding affinity using surface plasmon resonance and by ex vivo immunobinding on mouse and human GBM tissue. Tumour targeting by Cy5.5-labelled anti-IGFBP7 sdAb as well as by anti-IGFBP7 sdAb conjugated to PEGylated Fe₃O₄ nanoparticles (NPs)-Cy5.5 were assessed in U87MG.EGFRvIII tumour-bearing mice in vivo using optical imaging and in brain sections using fluorescent microscopy.

Results:

Surface plasmon resonance analyses revealed a medium affinity (K_D=40–50 nM) binding of the anti-IGFBP7 sdAb to the purified antigen. The anti-IGFBP7 sdAb also selectively bound to both mouse and human GBM vessels, but not normal brain vessels in tissue sections. In vivo, intravenously injected anti-IGFBP7 sdAb-Cy5.5 bound to GBM vessels creating high imaging signal in the intracranial tumour. Similarly, the anti-IGFBP7 sdAb-functionalised PEGylated Fe₃O₄ NP-Cy5.5 demonstrated enhanced tumour signal compared with non-targeted NPs. Fluorescent microscopy confirmed the presence of anti-IGFBP7 sdAb and anti-IGFBP7 sdAb-PEGylated Fe₃O₄ NPs selectively in GBM vessels.

Conclusions:

Anti-IGFBP7 sdAbs are novel GBM vessel-targeting moieties suitable for molecular imaging.

Single-Domain Antibodies as Therapeutic and Imaging Agents for the Treatment of CNS Diseases

Antibodies have become one of the most successful therapeutics for a number of oncology and inflammatory diseases. So far, central nervous system (CNS) indications have missed out on the antibody revolution, while they remain 'hidden' behind several hard to breach barriers. Among the various antibody modalities, single-domain antibodies (sdAbs) may hold the 'key' to unlocking the access of antibody therapies to CNS diseases. The unique structural features of sdAbs make them the smallest monomeric antibody fragments suitable for molecular targeting. These features are of particular importance when developing antibodies as modular building blocks for engineering CNS-targeting therapeutics and imaging agents. In this review, we first introduce the characteristic properties of sdAbs compared to traditional antibodies. We then present recent advances in the development of sdAbs as potential therapeutics across brain barriers, including their use for the delivery of biologics across the blood-brain and blood-cerebrospinal fluid (CSF) barriers, treatment of neurodegenerative diseases and molecular imaging of brain targets.

Perinatal iron deficiency affects locomotor behavior and water maze performance in adult male and female rats

Iron deficiency during early growth and development adversely affects multiple facets of cognition and behavior in adult rats. The purpose of this study was to assess the nature of the learning and locomotor behavioral deficits observed in male and female rats in the absence of depressed brain iron levels at the time of testing. Adult female Wistar rats were fed either an iron-enriched diet (>225 mg/kg Fe) or an iron-restricted diet (3 mg/kg Fe) for 2 wk prior to and throughout gestation, and a nonpurified diet (270 mg/kg Fe) thereafter. Open-field (OF) and Morris water maze (MWM) testing began when the offspring reached early adulthood (12 wk). At birth, perinatal iron-deficient (PID) offspring had reduced (P < 0.001) hematocrits (-33%), liver iron stores (-83%), and brain iron concentrations (-38%) compared with controls. Although there were no differences in iron status in adults, the PID males and females exhibited reduced OF exploratory behavior, albeit only PID males had an aversion to the center of the apparatus (2.5 vs. 6.9% in controls, P < 0.001). Additionally, PID males required greater path lengths to reach the hidden platform in the MWM, had reduced spatial bias for the target quadrant, and had a tendency for greater thigmotactic behavior in the probe trials (16.5 vs. 13.0% in controls; P = 0.06). PID females had slower swim speeds in all testing phases (-6.2%; P < 0.001). These results suggest that PID has detrimental programming effects in both male and female rats, although the behaviors suggest different mechanisms may be involved in each sex.

Small unilamellar vesicles: a platform technology for molecular imaging of brain tumors

Molecular imaging enables the non-invasive investigation of cellular and molecular processes. Although there are challenges to overcome, the development of targeted contrast agents to increase the sensitivity of molecular imaging techniques is essential for their clinical translation. In this study, spontaneously forming, small unilamellar vesicles (sULVs) (30 nm diameter) were used as a platform to build a bimodal (i.e., optical and magnetic resonance imaging (MRI)) targeted contrast agent for the molecular imaging of brain tumors. sULVs were loaded with a gadolinium (Gd) chelated lipid (Gd-DPTA-BOA), functionalized with targeting antibodies (anti-EGFR monoclonal and anti-IGFBP7 single domain), and incorporated a near infrared dye (Cy5.5). The resultant sULVs were characterized in vitro using small angle neutron scattering (SANS), phantom MRI and dynamic light scattering (DLS). Antibody targeted and nontargeted Gd loaded sULVs labeled with Cy5.5 were assessed in vivo in a brain tumor model in mice using time domain optical imaging and MRI. The results demonstrated that a spontaneously forming, nanosized ULVs loaded with a high payload of Gd can selectively target and image, using MR and optical imaging, brain tumor vessels when functionalized with anti-IGFBP7 single domain antibodies. The unique features of these targeted sULVs make them promising molecular MRI contrast agents.

Chronic prenatal ethanol exposure and increased concentration of fatty acid ethyl esters in meconium of term fetal Guinea pig

In humans, the occurrence of prenatal exposure to ethanol is difficult to validate objectively. Increased concentration of fatty acid ethyl esters (FAEE) in the meconium of the newborn may be a biomarker of prenatal ethanol exposure. The validity of this proposed biomarker was tested in pregnant guinea pigs that received chronic oral administration of 4 g ethanol/kg maternal body weight/day (n=8), isocaloric-sucrose/pair-feeding (n=8) or water (n=2) throughout gestation. At gestational day 65 (term, gestational day 66 to 69), each dam and her offspring were euthanized, and meconium was collected from the term fetal large intestine. Eight individual FAEE (lauric, myristic, palmitic, palmitoleic, stearic, oleic, linolenic and arachidonic AEE) were measured by gas chromatography--flame ionization detection and confirmed by gas chromatography--mass spectrometry. The chronic maternal ethanol regimen decreased fetal body weight and brain weight. There was virtually no measurable FAEE in the meconium for the water group (n=3 fetuses). For meconium of the ethanol offspring (n=25 fetuses) compared with the sucrose offspring (n=23 fetuses), the total FAEE concentration was 8-fold higher; and lauric, palmitic, stearic and oleic AEE concentrations were at least 5-fold higher for the ethanol group. The data indicate that fetal meconium FAEE constitute a biomarker of prenatal ethanol exposure for a maternal ethanol regimen that restricts fetal development, with an inverse relationship between meconium total FAEE concentration and both body weight and brain weight.

Chronic prenatal ethanol exposure increases glucocorticoid-induced glutamate release in the hippocampus of the near-term foetal guinea pig

Exposure to high cortisol concentration can injure the developing brain, possibly via an excitotoxic mechanism involving glutamate (Glu). The present study tested the hypothesis that chronic prenatal ethanol exposure (CPEE) activates the foetal hypothalamic-pituitary-adrenal axis to produce high cortisol exposure in the foetal compartment and alters sensitivity to glucocorticoid-induced Glu release in the foetal hippocampus. Pregnant guinea pigs received daily oral administration of ethanol (4 g/kg maternal body weight/day) or isocaloric-sucrose/pair-feeding from gestational day (GD) 2 until GD 63 (term, approximately GD 68) at which time they were euthanised, 1 h after their final treatment. Adrenocorticotrophic hormone (ACTH) and cortisol concentrations were determined in foetal plasma. Basal and electrically stimulated Glu and gamma-aminobutyric acid (GABA) efflux in the presence or absence of dexamethasone (DEX), a selective glucocorticoid-receptor agonist, were determined ex vivo in foetal hippocampal slices. Glucocorticoid receptor (GR), mineralocorticoid receptor (MR) and N-methyl-D-aspartate (NMDA) receptor NR1 subunit mRNA expression were determined in situ in the hippocampus and dentate gyrus. In the near-term foetus, CPEE increased foetal plasma ACTH and cortisol concentrations. Electrically stimulated glutamate, but not GABA, release was increased in CPEE foetal hippocampal slices. Low DEX concentration (0.3 microM) decreased stimulated glutamate, but not GABA, release in both CPEE and control foetal hippocampal slices. High DEX concentration (3.0 microM) increased basal release of Glu, but not GABA, in CPEE foetal hippocampal slices. GR, but not MR, mRNA expression was elevated in the hippocampus and dentate gyrus, whereas NR1 mRNA expression was increased in the CA1 and CA3 fields of the foetal hippocampus. These data demonstrate that CPEE increases high glucocorticoid concentration-induced Glu release in the foetal hippocampus, presumably as a consequence of increased GR expression. These effects of CPEE, coupled with increased glutamate release and increased NMDA receptor expression, may predispose the near-term foetal hippocampus to GR and Glu-NMDA receptor-mediated neurodevelopmental toxicity.

Fatty acid ethyl esters (FAEE); comparative accumulation in human and guinea pig hair as a biomarker for prenatal alcohol exposure

AIMS

To compare the incorporation rate (ICR) of fatty acid ethyl esters (FAEE) in hair between guinea pigs and humans, and to assess the relationship between ethanol exposure and FAEE concentrations in hair.

METHODS

Published data from pregnant guinea pigs, including maximum blood ethanol concentration (BEC), dosage regimen, and total hair FAEE concentration, were compared with published data from alcoholic patients, where dose of ethanol consumed and total hair FAEE concentration were reported. Mean values of ethanol Vmax for pregnant guinea pigs and humans were obtained from published data (26.2 and 24 mg/dl/h, respectively).

RESULTS

Total and individual FAEE ICRs, defined as the ratio of hair FAEE to the area under the BEC-time curve (total systemic ethanol exposure), were found to be on average an order of magnitude lower in the guinea pig than in the human. The profiles of ester incorporation also differed slightly between species, with ethyl stearate being highly incorporated in guinea pig hair and less so in human hair. The results may reflect in the human greater FAEE production, greater FAEE deposition in hair, slower FAEE catabolism, differential sebum production and composition, or a combination thereof. Also, ethyl oleate was found to correlate with total systemic ethanol exposure for both guinea pigs and humans, correlation coefficients equalling 0.67 (P < 0.05) and 0.49 (P < 0.05), respectively. No other ethyl esters, nor total FAEE, were found to correlate with systemic ethanol exposure.

CONCLUSION

When extrapolating FAEE concentrations in hair from guinea pigs to humans, an order of magnitude difference should be considered, with humans incorporating more FAEE per unit of ethanol exposure. Also, the results suggest caution should be taken when interpreting values of single esters because of their differential incorporation among species. Lastly, our findings suggest ethyl oleate may be of keen interest in FAEE hair analysis, particularly across species.

Integrated platform for brain imaging and drug delivery across the blood-brain barrier

The development of imaging and therapeutic agents against neuronal targets is hampered by the limited access of probes into the central nervous system across the blood-brain barrier (BBB). The evaluation of drug penetration into the brain in experimental models often requires complex procedures, including drug radiolabeling, as well as determinations in multiple animals for each condition or time point. Prospective in vivo imaging of drug biodistribution may provide an alternative to "classical" pharmacokinetics and biodistribution studies in that a contrast-enhanced imaging signal could serve as a surrogate for the amount of drug or biologic delivered to the organ of interest. For the brain-targeting applications, it is necessary to develop formulation strategies that enable a simultaneous drug and contrast agent delivery across the BBB. In this chapter, we describe methods for encapsulating drugs into liposome nanocarriers with surface display of both the imaging contrast agent for one or multiple imaging modalities and the single-domain antibody that undergoes receptor-mediated transcytosis across the BBB. Contrast-enhanced imaging signal detected in the brain after intravenous injection of such formulation(s) is proportional to the amount of drug delivered into the brain parenchyma. This method allows for a prospective, noninvasive estimation of drug delivery, accumulation, and elimination from the brain.

7-Fluorosialyl Glycosides Are Hydrolysis Resistant but Readily Assembled by Sialyltransferases Providing Easy Access to More Metabolically Stable Glycoproteins

The maintenance of therapeutic glycoproteins within the circulatory system is associated, in large part, with the integrity of sialic acids as terminal sugars on the glycans. Glycoprotein desialylation, either by spontaneous cleavage or through host sialidases, leads to protein clearance, mainly through the liver. Thus, the installation of minimally modified sialic acids that are hydrolysis-resistant yet biologically equivalent should lead to increased circulatory half-lives and improved pharmacokinetic profiles. Here we describe the chemoenzymatic synthesis of CMP-sialic acid sugar donors bearing fluorine atoms at the 7-position, starting from the corresponding 4-deoxy-4-fluoro-N-acetylhexosamine precursors. For the derivative with natural stereochemistry we observe efficient glycosyl transfer by sialyltransferases, along with improved stability of the resultant 7-fluorosialosides toward spontaneous hydrolysis (3- to 5-fold) and toward cleavage by GH33 sialidases (40- to 250-fold). Taking advantage of the rapid transfer of 7-fluorosialic acid by sialyltransferases, we engineered the O-glycan of Interferon α-2b and the N-glycans of the therapeutic glycoprotein α1-antitrypsin. Studies of the uptake of the glyco-engineered α1-antitrypsin by HepG2 liver cells demonstrated the bioequivalence of 7-fluorosialic acid to sialic acid in suppressing interaction with liver cell lectins. In vivo pharmacokinetic studies reveal enhanced half-life of the protein decorated with 7-fluorosialic acid relative to unmodified sialic acid in the murine circulatory system. 7-Fluorosialylation therefore offers considerable promise as a means of prolonging circulatory half-lives of glycoproteins and may pave the way toward biobetters for therapeutic use.

Microbubble drug conjugate and focused ultrasound blood brain barrier delivery of AAV-2 SIRT-3

BACKGROUND

Delivery of viral vectors as gene therapies to treat neurodegenerative diseases has been hampered by the inability to penetrate the blood brain barrier (BBB) and invasive or non-targeted delivery options prone to inducing immune responses. MR guided focused ultrasound (MR-g-FUS) and microbubbles have demonstrated safe, temporary, targeted BBB permeabilization clinically.

METHODS

We developed clinically scalable, microbubble drug conjugates (MDCs) for the viral gene therapy, AAV.SIRT3-myc [adeno-associated virus expressing myc-tagged SIRT3], which has previously been shown to have disease modifying effects in animal models of Parkinson's disease (PD). The lipid shells of the perfluorocarbon gas MDCs were covalently conjugated to antibodies with binding specificity to AAVs. Following systemic (iv) delivery of AAV.SIRT3-myc MDCs, MR-g-FUS was used to deliver SIRT3-myc to brain regions affected in PD. SIRT3-myc expression was determined post mortem, using immunohistochemistry.

RESULTS

An in vitro, SH-SY5Y cell culture model was used to show that the localized destruction of MDCs using ultrasound exposures within biological safety limits dissociated AAV2-GFP (green fluorescent protein) from the MDCs in the targeted area while maintaining their transduction capacity. In rats, MR-g-FUS resulted in BBB permeabilization in the striatum and substantia nigra (SNc). SIRT3-myc was expressed in the striatum, but not the SNc.

CONCLUSION

These studies demonstrate that MDCs combined with MR-g-FUS are an effective method for delivery of viral vector gene therapies, such as AAV.SIRT3, to brain regions affected in PD. This technology may prove useful as a disease-modifying strategy in PD and other neurodegenerative disorders.

A Guinea pig model for the identification of in utero alcohol exposure using fatty acid ethyl esters in neonatal hair

Measuring levels of fatty acid ethyl esters (FAEE) in hair has been a useful way to discriminate between adult heavy and nondrinkers. Extending the use of FAEE into neonatal hair to objectively identify children exposed to alcohol in utero may revolutionize current methods used to diagnose fetal alcohol spectrum disorder (FASD). Here we confirm for the first time that chronic exposure to alcohol during pregnancy in guinea pigs leads to increased levels of FAEE in both maternal and neonatal hair. The mean cumulative FAEE concentration in exposed maternal samples taken at GD57 was 0.431+/-0.140 pmol/mg (mean+/-SEM); levels observed in corresponding sucrose and water controls were 10-fold lower. Similarly, FAEE concentrations in exposed offspring samples taken at postnatal d 1 (mean cumulative FAEE=0.491+/-0.177 pmol/mg) were more than 15-fold higher than control counterparts. Sixty percent of all alcohol-exposed animal samples contained two or more quantifiable FAEE, whereas close to 90% of either water or sucrose control samples did not have more than one quantifiable level of a single FAEE. Results of this study suggest that FAEE in neonatal hair may be useful biomarkers in identifying in utero alcohol exposure and may facilitate the early diagnosis and treatment of FASD.

Spatial learning deficits induced by chronic prenatal ethanol exposure can be overcome by non-spatial pre-training

This study tested the hypothesis that behavioural intervention, in the form of non-spatial pre-training, mitigates the deficits in spatial learning tasks induced in guinea pig offspring by chronic prenatal ethanol exposure (CPEE). Timed, pregnant guinea pigs were treated with ethanol (4 g/kg maternal body weight/day), isocaloric-sucrose/pair-feeding, or water throughout gestation. Offspring received non-spatial pre-training, in which animals were exposed to the procedural requirements of the water maze in the absence of distal spatial cues, and then were tested in both stationary-platform and moving-platform tasks with spatial cues. Saliva cortisol was quantified in non-trained and pre-trained animals before and after exposure to the water maze.

RESULTS

CPEE offspring exhibited performance deficits in the stationary-platform task, and non-spatial pre-training improved performance of CPEE offspring to control levels. In contrast, non-spatial pre-training had no effect on the impaired performance of CPEE offspring in the moving-platform task. Non-trained CPEE offspring had elevated saliva cortisol concentration after water-maze exposure compared to control offspring. Moreover, pre-trained control animals exhibited a sensitization of the cortisol response after repeated exposure to the water maze, and this was not evident in pre-trained CPEE offspring.

CONCLUSIONS

These data demonstrate that CPEE produced deficits in spatial learning and memory processes that were partially overcome by non-spatial pre-training; however, more difficult tasks continued to reveal cognitive deficits. For repeated exposure to the water maze, CPEE offspring achieved a level of performance that was not different from control offspring, suggesting that it is the initial rate of acquisition of new learning, rather than the overall ability to learn, that is most adversely affected by CPEE.

Ethnicity does not affect outcomes of coronary angioplasty

BACKGROUND

Access to high quality medical care and especially to complex procedures may be adversely affected in members of a minority ethnic group or a lower socioeconomic class. For example, Caucasians undergo coronary artery bypass grafting (CABG) or percutaneous transluminal coronary interventions (PTCI) twice as frequently as African-Americans. Data exist to suggest that African-Americans derive less benefit than Caucasians from CABG.

HYPOTHESIS

We investigated the possibility that outcomes of catheter-based coronary angioplasty might also be less favorable in minority populations.

METHODS

We analyzed in-hospital outcomes in 6,559 consecutive patients who underwent PTCI in our laboratory. In 37 ethnicity was classified as "other," 5,203 (79.8%) were identified as Caucasians, 863 (13.2%), as African-Americans, and 456 (7.0%), as Hispanics. Twelve baseline clinical, angiographic, and procedural characteristics were entered into a computerized data base. Hospital complications were identified by trained quality assurance nurses.

RESULTS

Substantial differences in baseline characteristics existed between the populations. Despite these differences, on univariate comparison of ethnicity and outcome, no differences between ethnic groups were found with a single exception. Mortality in Hispanics was higher than in the other two populations. (2.0 vs. 0.7 and 0.8%, respectively, p = 0.008). However, when this was adjusted for baseline characteristics, the difference was not significant.

CONCLUSIONS

In contrast to previous studies suggesting less favorable outcomes of CABG in African-American patients, this analysis demonstrates an equal frequency of procedural success and rate of hospital complications for PTCI in that population, in Hispanics, and in Caucasians.

Chronic prenatal ethanol exposure alters glucocorticoid signalling in the hippocampus of the postnatal Guinea pig

The present study tested the hypothesis that chronic prenatal ethanol exposure causes long-lasting changes in glucocorticoid signalling in postnatal offspring. Pregnant guinea pigs were treated with ethanol (4 g/kg maternal body weight/day), isocaloric-sucrose/pair-feeding or water throughout gestation, and maternal saliva cortisol concentration was determined 2 h after treatment at different stages of gestation. Electrically-stimulated release of glutamate and GABA, in the presence or absence of dexamethasone, as well as glucocorticoid and mineralocorticoid receptor mRNA expression, was determined in the hippocampus and prefrontal cortex of adult offspring of treated pregnant guinea pigs. Maternal saliva cortisol concentration increased throughout pregnancy, which was associated with increased foetal plasma and amniotic fluid cortisol concentration. Ethanol administration to pregnant guinea pigs increased maternal saliva cortisol concentration during early and mid-gestation. In late gestation, ethanol administration did not increase saliva cortisol concentration above that induced by pregnancy. Chronic prenatal ethanol exposure had no effect on stimulated glutamate or GABA release, but selectively prevented dexamethasone-mediated suppression of stimulated glutamate release, and decreased expression of mineralocorticoid, but not glucocorticoid, receptor mRNA in the hippocampus of adult offspring. These data indicate that maternal ethanol administration leads to excessively increased maternal cortisol concentration that can impact negatively the developing foetal brain, leading to persistent postnatal deficits in glucocorticoid regulation of glutamate signalling in the adult hippocampus.

Mechanistic insight into the induction of cellular immune responses by encapsulated and admixed archaeosome-based vaccine formulations

Archaeosomes are liposomes formulated using total polar lipids (TPLs) or semi-synthetic glycolipids derived from archaea. Conventional archaeosomes with entrapped antigen exhibit robust adjuvant activity as demonstrated by increased antigen-specific humoral and cell-mediated responses and enhanced protective immunity in various murine infection and cancer models. However, antigen entrapment efficiency can vary greatly resulting in antigen loss during formulation and variable antigen:lipid ratios. In order to circumvent this, we recently developed an admixed archaeosome formulation composed of a single semi-synthetic archaeal lipid (SLA, sulfated lactosylarchaeol) which can induce similarly robust adjuvant activity as an encapsulated formulation. Herein, we evaluate and compare the mechanisms involved in the induction of early innate and antigen-specific responses by both admixed (Adm) and encapsulated (Enc) SLA archaeosomes. We demonstrate that both archaeosome formulations result in increased immune cell infiltration, enhanced antigen retention at injection site and increased antigen uptake by antigen-presenting cells and other immune cell types, including neutrophils and monocytes following intramuscular injection to mice using ovalbumin as a model antigen. In vitro studies demonstrate SLA in either formulation is preferentially taken up by macrophages. Although the encapsulated formulation was better able to induce antigen-specific CD8⁺ T cell activation by dendritic cells in vitro, both encapsulated and admixed formulations gave equivalently enhanced protection from tumor challenge when tested in vivo using a B16-OVA melanoma model. Despite some differences in the immunostimulatory profile relative to the SLA (Enc) formulation, SLA (Adm) induces strong in vivo immunogenicity and efficacy, while offering an ease of formulation.

Low-Cost Real-Time PPP/INS Integration for Automated Land Vehicles

The last decade has witnessed a growing demand for precise positioning in many applications including car navigation. Navigating automated land vehicles requires at least sub-meter level positioning accuracy with the lowest possible cost. The Global Navigation Satellite System (GNSS) Single-Frequency Precise Point Positioning (SF-PPP) is capable of achieving sub-meter level accuracy in benign GNSS conditions using low-cost GNSS receivers. However, SF-PPP alone cannot be employed for land vehicles due to frequent signal degradation and blockage. In this paper, real-time SF-PPP is integrated with a low-cost consumer-grade Inertial Navigation System (INS) to provide a continuous and precise navigation solution. The PPP accuracy and the applied estimation algorithm contributed to reducing the effects of INS errors. The system was evaluated through two road tests which included open-sky, suburban, momentary outages, and complete GNSS outage conditions. The results showed that the developed PPP/INS system maintained horizontal sub-meter Root Mean Square (RMS) accuracy in open-sky and suburban environments. Moreover, the PPP/INS system could provide a continuous real-time positioning solution within the lane the vehicle is moving in. This lane-level accuracy was preserved even when passing under bridges and overpasses on the road. The developed PPP/INS system is expected to benefit low-cost precise land vehicle navigation applications including level 2 of vehicle automation which comprises services such as lane departure warning and lane-keeping assistance.

Safety and biodistribution of sulfated archaeal glycolipid archaeosomes as vaccine adjuvants

Archaeosomes are liposomes comprised of ether lipids derived from various archaea. Unlike conventional ester-linked liposomes, archaeosomes exhibit high pH and thermal stability. As adjuvants, archaeosomes can induce robust, long-lasting humoral and cell-mediated immune responses and enhance protection in murine models of infectious disease and cancer. Archaeosomes constituted with total polar lipids (TPL) of various archaea are relatively complex, comprising >10 different lipid compounds. Archaeosomes can be constituted with semi-synthetic glycerolipids built on ether-linked isoprenoid phytanyl cores with varied synthetic glycol- and amino-head groups. However, such semi-synthetic archaeosomes involve many synthetic steps to arrive at the final desired glycolipid composition. We have developed a novel archaeosome formulation comprising a sulfated saccharide group covalently linked to the free sn-1 hydroxyl backbone of an archaeal core lipid (sulfated S-lactosylarchaeol, SLA) mixed with uncharged glycolipid (lactosylarchaeol, LA). This new class of adjuvants can be easily synthesized and retains strong immunostimulatory activity for induction of cell-mediated immunity following systemic immunization. Herein, we demonstrate the safety of SLA/LA archaeosomes following intramuscular injection to mice and evaluate the immunogenicity, in vivo distribution and cellular uptake of antigen (ovalbumin) encapsulated into SLA/LA archaeosomes. Overall, we have found that semi-synthetic sulfated glycolipid archaeosomes are a safe and effective novel class of adjuvants capable of inducing strong antigen-specific immune responses in mice and protection against subsequent B16 melanoma tumor challenge. A key step in their mechanism of action appears to be the recruitment of immune cells to the injection site and the subsequent trafficking of antigen to local draining lymph nodes.

Isolation of functional single domain antibody by whole cell immunization: implications for cancer treatment

Carcinoembryonic antigen related cell adhesion molecule (CEACAM) 6 is over-expressed in different types of cancer cells. In addition, it has also been implicated in some infectious diseases. Targeting this molecule by an antibody might have applications in diverse tumor models. Single domain antibody (sdAb) is becoming very useful format in antibody engineering as potential tools for treating acute and chronic disease conditions such as cancer for both diagnostic as well as therapeutic application. Generally, sdAbs with good affinity are isolated from an immune library. Discovery of a new target antigen would require a new immunization with purified antigen which is not always easy. In this study, we have isolated, by phage display, an sdAb against CEACAM6 with an affinity of 5 nM from a llama immunized with cancer cells. The antibody has good biophysical properties, and it binds to the cells expressing the target antigen. Furthermore, it reduces cancer cells proliferation in vitro and shows an excellent tumor targeting in vivo. This sdAb could be useful in diagnosis as well as therapy of CEACAM6 expressing tumors. Finally, we envisage it would be feasible to isolate good sdAbs against other interesting tumor associated antigens from this library. Therefore, this immunization method could be a general strategy for isolating sdAbs against any surface antigen without immunizing the animal with the antigen of interest each time.

Co-occurrence of second primary malignancy in patients with thyroid cancer

BACKGROUND

The discovery of asynchronous or synchronous double or multiple malignancies in patients is not uncommon. The co-occurrence of second primary malignancy (SPM) could be randomly occurring or association with risk factors such as environmental, genetic predisposition and therapy-related.

MATERIALS AND METHODS

We retrieved ∼782 million claim records consisting of 10.8 million males and 10.6 million females from Taiwan's National Health Insurance, which were collected for a period of 3 years (January 2000-December 2002). All the patient records were stratified by gender and ages at a 20-year interval with SPMs and specific groups. Interestingness or Q-value was used to measure strength of the disease-disease associations.

RESULTS

A total of 9423 thyroid cancer (female: 7483, male: 1940), 276 184 SPM (female: 141 023, male: 135 161) and 861 co-occurrence cases (female: 583, male: 278) were recorded. The co-occurrence incidence rate of head and neck, breast, digestive system and lung was 1.93%, 1.59%, 1.44% and 1.18%, respectively. Malignancy of salivary glands, laryngx, sarcoma, lymphoid tissue, mouth, central nervous system and lungs found Q-value >10. Malignancies with intermediate Q-values (5.0-9.9) were observed in nasopharynx, kidney and ureter, breast, stomach and skin. Prostate, leukemia, urinary bladder, ovary, colon, liver and uterine cervix cancer have lower Q-values (1.0-4.9).

CONCLUSION

Co-occurrence ratio of thyroid cancer and SPM was high, occurred in all organ systems. We postulated that the aggressive use of modern diagnostic modalities, aggressive radioiodine treatment, pre-existing molecular oncogen mutations, and thyroid hormone for simultaneously supple-mentary and suppressive therapies were responsible.