Dendrimer-encapsulated nanoparticle-core micelles as a modular strategy for particle-in-a-box-in-a-box nanostructures.

The hierarchically controlled synthesis and characterization of self-assembling macromolecules and particles are key to explore and exploit new nanomaterials. Here we present a versatile strategy for constructing particle-in-a-box-in-a-box systems by assembling dendrimer-encapsulated gold nanoparticles (DENs) into dendrimicelles. This is realized by combining positively charged PAMAM dendrimers with a negative-neutral block copolymer. The number of particles per dendrimicelle can be controlled by mixing DENs with empty PAMAM dendrimers. The dendrimicelles are stable in solution for months and provide improved resistance for the nanoparticles against degradation. The dendrimicelle strategy provides a flexible platform with a plethora of options for variation in the type of nanoparticles, dendrimers and block copolymers used, and hence is tunable for applications ranging from nanomedicine to catalysis.

Mechanical properties derived from phase separation in co-polymer hydrogels.

Hydrogels can be synthesized with most of the properties needed for biomaterials applications. Soft, wettable, and highly permeable gels with a practically unlimited breadth of chemical functionalities are routinely made in the laboratory. However, the ability to make highly elastic and durable hydrogels remains limited. Here we describe an approach to generate stretchy, durable hydrogels, employing a high polymer-to-crosslink ratio for extensibility, combined with an aggregating copolymer phase to provide stability against swelling. We find that the addition of aggregating co-polymer can produce a highly extensible gel that fails at 1000% strain, recovers from large strains within a few minutes, maintains its elasticity over repeated cycles of large amplitude strain, and exhibits significantly reduced swelling. We find that the gel׳s enhanced mechanical performance comes from a kinetically arrested structure that arises from a competition between the disparate polymerization rates of the two components and the aggregation rate of the unstable phase. These results represent an alternative strategy to generating the type of stretchy elastomer-like hydrogels needed for biomedical technologies.

Adherence, exposure and patients' experiences with the use of erlotinib in non-small cell lung cancer.

PURPOSE: Erlotinib is an orally administered tyrosine kinase inhibitor used for treatment of non-small cell lung cancer. Understanding actual use of medication is essential for optimizing treatment conditions. METHODS: In this multicentre prospective observational study, patients starting erlotinib treatment were followed for 4 months. Adherence was assessed using a medication event monitoring system (MEMS). Area under the curve (AUC) was determined after 1, 2 and 4 months. Before start and at monthly intervals, patients filled out questionnaires about attitude towards medication and disease, quality of life, symptoms and use in daily practice. RESULTS: Sixty-two patients (median age 63.5 years, 53 % male) were included of whom 15 were still on treatment after 4 months. MEMS data of 55 patients revealed a mean adherence of 96.8 ± 4.0 %. Over one-third of patients had an adherence rate <95 %. At 1 month, 21 % of patients did not always correctly take erlotinib without food. Associated risk factors were older age, suboptimal adherence, ocular symptoms and stomatitis (all p < 0.05). After 1 month of treatment, fatigue (91 %) and rash (86 %) were the most common symptoms reported. AUCss of erlotinib was higher in patients with rash and patients with moderate-severe anorexia (both p < 0.05). CONCLUSION: Though adherence to erlotinib treatment is generally high, non-adherence might be an issue in a considerable number of patients. To support optimal erlotinib intake, clinicians need to take adequate measures to ameliorate symptoms and to address adherence and correct intake without food. Especially older patients and those who experience stomatitis may need extra attention.

Transcriptional profiling of the lectin ArathEULS3 from Arabidopsis thaliana toward abiotic stresses.

The family of EUL-related lectins groups all proteins with an Euonymus lectin (EUL) domain, a protein motif which is highly conserved throughout the plant kingdom and occurs as part of many chimeric proteins with different domain architectures. The S3 type EUL lectin from Arabidopsis thaliana (ArathEULS3) has become the model protein within this EUL family. Based on sequence homology to an ABA/NaCl inducible gene from rice and some publicly available high-throughput micro-array data, it was hypothesized that ArathEULS3 is transcriptionally regulated by osmotic stress responses. Here we present a detailed expression analysis of the ArathEULS3 lectin gene. Under normal growth conditions, ArathEULS3 is stably expressed throughout plant development. After ABA, NaCl and methyl jasmonate (MeJA) treatments transcription is upregulated. Furthermore, in silico promoter and co-expression analyses suggested the A. thaliana Homeobox 7 (ATHB-7) as a candidate transcription factor that may regulate ArathEULS3 expression. Taken together, our data confirm that the ArathEULS3 lectin gene indeed shows a stress-inducible expression pattern. We speculate on a role for ArathEULS3 in the plant stress response.

Zebrafish: a nontraditional model of traditional medicine.

With a modern rise in the use of traditional medicines has come a need for model organisms that are amenable not only to treatment with these remedies, but also to testing the large number of potential therapeutics this field presents. The high-fecundity and rapid generation time of the zebrafish makes it a natural candidate for this endeavor. Additionally, the zebrafish shares genetic, anatomic and physiologic homology to higher order vertebrates. This review surveys the present state of phytotherapy research utilizing the zebrafish model organism. The studies herein described utilize the zebrafish for investigating plant-based effectors of hypercholesterolemia, angiogenesis, Parkinson's and Alzheimer's. In addition to reviewing the present state of research in this area, the philosophical intersection of modern and traditional medical paradigms is discussed and future directions for investigations at this junction are suggested.

Determination of lymphatic vascular identity and developmental timecourse in zebrafish (Danio rerio).

Zebrafish lymphatics have been shown to share a number of characteristics with their human counterparts, making the fish a potentially useful model for studying lymphatic development and disease. The utility of the zebrafish lymphatic model would be substantially enhanced by an improved understanding of the spatiotemporal development of the primary lymphatic vasculature. The goal of this project is to identify and map the major zebrafish lymphatic structures throughout embryonic to early juvenile stages of development. Two transgenic lines, kdr-1:RASmCherryxfli1:GFP and stabilin1:YFP, were recently derived to assist in the study of developing lymphatic vasculature, but their specificity has not been rigorously tested. In the course of the present study, we experimentally validate the utility of these two marker lines as potential tools for establishing lymphatic vascular identity and visualizing developmental lymphangiogenesis. We introduced twenty nanometer red florescent microspheres into the blood vasculature of flil:GFP zebrafish and collected tiled optical z-sections at time intervals spanning early development. Three-dimensional reconstructions of the vasculature were used to differentiate between blood and lymphatic vessels. Age-matched injected embryos were compared to the two transgenic lines to further assess their specificity. We created a spatiotemporal map of the major lymphatic vessels in the developing zebrafish including a previously unidentified lymphatic vessel in the gastrointestinal tract. We conclude that the kdr-1:RASmCherryxfli1:GFP line accurately identifies developing lymphatic vessels with the exception of those associated with the gastrointestinal tract. The stabilin1:YFP line, however, is less reliable, as it marks both venous vessels and lymphatic vessels.

Evaluation of zebrafish embryos as a model for assessing inhibition of hERG.

INTRODUCTION: It has been proposed that the analysis of heart rate in zebrafish embryos can be used to assess the potential effects of compounds on hERG. The purpose of this study was to investigate the effect of compounds on the heart rate and atrioventricular dissociation in zebrafish. The compounds investigated were chosen based on the association or lack of association with QTc prolongation in the clinic. METHODS: Three-day-old embryos were incubated in buffered embryo medium. On the day of the study, fish were placed in a petri dish containing 5.0 mL of embryo medium and 125 mg/L MS-222 anesthetic. Drugs to be tested were added to the medium from a stock solution to achieve the desired target concentration. Ten fish were incubated in each concentration of drug for 80 min. Beat rates of the atrium and ventricle were recorded after the incubation by counting beats of the respective chambers using standard brightfield stereomicroscopy. RESULTS: All of the compounds associated with QT prolongation induced dissociation between the atrium and ventricular rates except D,L-sotalol and procainamide. The concentrations that induced dissociation tended to be higher than the hERG IC50. None of the negative control compounds caused atrioventricular dissociation at clinically efficacious concentrations. DISCUSSION: In conclusion, the present data demonstrate that zebrafish can be utilized to assess the effects of chemicals on hERG. However, the practical use of this assay may be difficult because of the high concentrations that must be reached to see those pharmacological effects.

Outcome after three years of laronidase enzyme replacement therapy in a patient with Hurler syndrome.

Enzyme replacement therapy (ERT) with laronidase, recombinant alpha-L-iduronidase, for mucopolysaccharidosis type I (MPS I) has been clinically available since April 2003. Pre-approval studies were performed on patients with the more attenuated forms of MPS I, Hurler-Scheie and Scheie syndromes. The clinical efficacy of laronidase on the severe form of MPS I, Hurler syndrome, is not well known. We present a patient with Hurler syndrome who has been treated with laronidase for 3 years. Clinically, the patient demonstrated improvement in urinary glycosaminoglycan (GAG) levels and hepatomegaly, but continued to experience decline in respiratory status, musculoskeletal and spinal involvement, and developmental skills. Overall, the benefit of ERT with laronidase in advanced Hurler syndrome appeared to be minimal in this patient.

MRI of the brain and cervical spinal cord in rhizomelic chondrodysplasia punctata.

BACKGROUND: The classic rhizomelic chondrodysplasia punctata (RCDP) phenotype involves a typical facial appearance, cataracts, skeletal dysplasia causing disproportionate somatic growth failure, microcephaly, and severe psychomotor defects. Biochemical abnormalities include impaired plasmalogen biosynthesis in all forms of RCDP and accumulation of phytanic acid in RCDP type 1. A subset of patients has a milder clinical and biochemical phenotype, with less severe neurologic impairment and an incomplete deficiency in plasmalogens. The impact of plasmalogen deficiency on neurologic function is severe, causing spasticity and mental defects, but its pathomechanism is still unknown. The authors specifically focused on myelination because myelin is rich in ethanolamine plasmalogens. OBJECTIVE: To define the neuroimaging characteristics of the genetic peroxisomal disorder RCDP. METHODS: Twenty-one MR images of the brain and cervical spine of 11 patients were evaluated and correlated with neurologic and biochemical profiles. RESULTS: No abnormalities on MRI were seen in the patients with a mild phenotype of RCDP, whereas delayed myelination, ventricular enlargement and increased subarachnoidal spaces, supratentorial myelin abnormalities, and cerebellar atrophy were observed in patients with the severe phenotype of both RCDP type 1 and 3. The severity of both the MRI abnormalities and the clinical phenotype is correlated with the plasmalogen level. CONCLUSIONS: The severe phenotype of rhizomelic chondrodysplasia punctata (RCDP) is accompanied by a specific pattern of both developmental and regressive MRI abnormalities. Plasmalogen levels seem to play an important role in the pathophysiology of CNS abnormalities in RCDP. Increased phytanic acid appears not to be the cause of cerebellar atrophy.

Expanded motor and psychiatric phenotype in autosomal dominant Segawa syndrome due to GTP cyclohydrolase deficiency.

BACKGROUND: Segawa syndrome due to GTP cyclohydrolase deficiency is an autosomal dominant disorder with variable expression, that is clinically characterised by l-dopa responsive, diurnally fluctuating dystonia and parkinsonian symptoms. OBJECTIVE: To delineate the neurological and psychiatric phenotype in all affected individuals of three extended families. METHODS: GTP cyclohydrolase deficiency was documented by biochemical analyses, enzymatic measurements in fibroblasts, and molecular investigations. All affected individuals were examined neurologically, and psychiatric data were systematically reviewed. RESULTS: Eighteen affected patients from three families with proven GTP cyclohydrolase deficiency were identified. Eight patients presenting at less than 20 years of age had typical motor symptoms of dystonia with diurnal variation. Five family members had late-presenting mild dopa-responsive symptoms of rigidity, frequent falls, and tendonitis. Among mutation carriers older than 20 years of age, major depressive disorder, often recurrent, and obsessive-compulsive disorder were strikingly more frequent than observed in the general population. Patients responded well to medication increasing serotonergic neurotransmission and to l-dopa substitution. Sleep disorders including difficulty in sleep onset and maintenance, excessive sleepiness, and frequent disturbing nightmares were present in 55% of patients. CONCLUSION: Physicians should be aware of this expanded phenotype in affected members of families with GTP cyclohydrolase deficiency.

First-order phase transition in easy-plane quantum antiferromagnets.

Quantum phase transitions in Mott insulators do not fit easily into the Landau-Ginzburg-Wilson paradigm. A recently proposed alternative to it is the so-called deconfined quantum criticality scenario, providing a new paradigm for quantum phase transitions. In this context it has recently been proposed that a second-order phase transition would occur in a two-dimensional spin 1/2 quantum antiferromagnet in the deep easy-plane limit. A check of this conjecture is important for understanding the phase structure of Mott insulators. To this end we have performed large-scale Monte Carlo simulations on an effective gauge theory for this system, including a Berry-phase term that projects out the S=1/2 sector. The result is a first-order phase transition, thus contradicting the conjecture.

Benzoate treatment and the glycine index in nonketotic hyperglycinaemia.

High-dose benzoate treatment aimed at reducing plasma glycine levels to normal reduces seizures and increases wakefulness in patients with nonketotic hyperglycinaemia (NKH). Since benzoate metabolism is dependent on the available glycine pool, and since the glycine pool is variably affected by the deficiency in the glycine cleavage enzyme system, we examined the importance of interpatient variability in benzoate requirement. To correct for the dietary glycine contribution, the glycine index was introduced as the molar requirement of benzoate dose necessary to normalize plasma glycine levels and subtracting from that the dietary glycine intake, both corrected for weight. The glycine index varied between 3.62 and 4.87 mmol/kg per day in five patients with a poor neurodevelopmental outcome and between 0.92 and 1.90 mmol/kg per day in four patients with a better neurodevelopmental outcome, and was 2.54 mmol/kg per day in a single patient with an intermediate outcome. The glycine index was stable over time within each patient. Exceeding the balance by either increasing food glycine intake or decreasing the benzoate dose resulted in increased glycine levels. Exceeding the glycine tolerance by increasing benzoate resulted in elevated and toxic levels of benzoate. The glycine index is a stable, individually specific parameter in patients with NKH. It has clinical consequences for the dose of benzoate required and the role of dietary management. Through its correlation with neurodevelopmental outcome, the glycine index points to potential genetic factors that could contribute to the psychomotor retardation in NKH.

Density of states determined from Monte Carlo simulations.

We describe a method for calculating the density of states by combining several canonical Monte Carlo runs. We discuss how critical properties reveal themselves in g (epsilon) and demonstrate this by applying the method to several different phase transitions. We also demonstrate how this can used to calculate the conformal charge, where the dominating numerical method has traditionally been the transfer matrix.

Natural history of nonketotic hyperglycinemia in 65 patients.

BACKGROUND: Glycine encephalopathy, also known as nonketotic hyperglycinemia (NKH), is an autosomal recessive disorder caused by a defect in the glycine cleavage system. NKH is classically associated with neonatal apnea, lethargy, hypotonia, and seizures, followed by severe psychomotor retardation in those who survive. METHODS: To determine the natural history of NKH, the authors mailed a 44-question survey to 170 households in the International NKH Family Network. RESULTS: Data for 65 patients (36 boys, 29 girls) were collected from 58 families. One-third of the subjects died; 8 girls died during the neonatal period, and 14 patients died thereafter (2 girls, 12 boys). Median age of death for boys was 2.6 years vs <1 month for girls (p = 0.02). Mean birth weight and length, occipitofrontal circumference, and gestation duration were normal. Two-thirds of infants were ventilated during the neonatal period; of these, 40% died. Ninety percent had confirmed seizures, 75% during the first month of life. Interestingly, three NKH patients never developed seizures. An abnormal corpus callosum and/or hydrocephalus were associated with especially poor gross motor and speech development. Of 25 patients living > or =3 years, 10 were able to walk and say/sign words; all were boys. In six families with more than one affected child, disease course and mortality were similar within each family. CONCLUSIONS: This study reveals a striking and unexpected gender difference in mortality and developmental progress. Of the two-thirds of nonketotic hyperglycinemia patients surviving the newborn period, up to 20% (mostly boys) may learn to walk and communicate by saying or signing words.

Structure elucidation of sildenafil analogues in herbal products.

The structure of unknown compounds present in herbal products was elucidated using liquid chromatography-electrospray ionization-mass spectrometry, direct-infusion electrospray ionization-mass spectrometry, and nuclear magnetic resonance. Compounds 1-3 were identified as sildenafil analogues, 1 bearing an N-ethylpiperazine moiety instead of an N-methylpiperazine, and an acetyl group instead of the sulfonyl group, named acetildenafil, 2 bearing an N-ethylpiperazine moiety instead of an N-methylpiperazine (homosildenafil), and 3 bearing an N-hydroxylethylpiperazine moiety instead of an N-methylpiperazine, named hydroxyhomosildenafil. When analysing products marketed for penile erectile dysfunction or marketed as aphrodisiacs, attention should be given to the possible presence of these components.

Association between vascular dysfunction and reduced myocardial flow reserve in patients with hypertension: a LIFE substudy.

Impaired myocardial flow reserve (MFR) has been demonstrated in hypertension, and has been associated with peripheral vascular changes. We investigated whether MFR was impaired and associated with structural and/or functional vascular changes in hypertensive patients without evidence of coronary artery disease (CAD). We measured left ventricular (LV) mass index by echocardiography and MFR by positron emission tomography in 33 unmedicated, hypertensive patients with electrocardiographic LV hypertrophy without CAD, and 15 age- and gender-matched normotensive subjects. We also measured 24-h ambulatory blood pressure, minimal forearm vascular resistance (MFVR) by plethysmography, media:lumen ratio in isolated, subcutaneous resistance arteries by myography, intima-media cross-sectional area of the common carotid artery, and flow-mediated (FMD) and nitroglycerin-induced dilatation (NID) of the brachial artery by ultrasound. Compared to the controls, the patients had impaired MFR (2.4 (95% CI 1.95-2.8) vs 3.4 (2.7-4.2), P<0.01) due to increased resting myocardial blood flow (MBF) (0.82 (0.73-0.91) vs 0.65 (0.56-0.75) ml/g min), and decreased dipyridamole-stimulated MBF (1.80 (1.55-2.1) vs 2.3 (1.80-2.8) ml/g min, both P<0.05). The difference in resting MBF disappeared (80 (74-87) vs 86 (74-97) microl/kg mmHg, NS) when normalized for blood pressure and heart rate. MFR correlated negatively to median 24-h systolic blood pressure (r=-0.50, P<0.01) as well as to LV mass index (r=-0.45, P<0.05) and MFVR in men (r=-0.47, P<0.05), and positively to FMD (r=0.44, P<0.05) and NID (r=0.40, P<0.05). Hypertensive patients with electrocardiographic LV hypertrophy without CAD had impaired MFR associated with cardiovascular hypertrophy and vasodilatory dysfunction. This suggests that MFR is impaired by LV hypertrophy and structural/functional vascular damage in the coronary and noncoronary circulation.

Electrocardiographic characterization of embryonic zebrafish.

The zebrafish (Danio rerio) has emerged as one of the primary experimental models of developmental cardiovascular research. Recent progress in flow visualization techniques along with the existing genetic map of the species has made zebrafish amenable to a variety of experiments relating cardiac developmental structure and function. One essential tool in establishing the proper functioning of the heart is the electrocardiogram (ECG). This study presents a methodology whereby the ECGs of embryonic zebrafish could be used in assessing the electrophysiological consequences of genetically-, mechanically-, or pharmacokinetically-induced cardiac perturbations. Five day post-fertilization (dpf) embryos produced repeating bimodal ECGs with clearly distinguished atrial (P) and ventricular (R) depolarization waves. P-R intervals along with P-P intervals are cited.

Criticality versus q in the (2+1)-dimensional Zq clock model.

Using Monte Carlo simulations we have studied the d=3 Z(q) clock model in two different representations, the phase representation and the loop-gas/dumbbell-gas representation. We find that for q> or =5 the critical exponents alpha and nu for the specific heat and the correlation length, respectively, take on values corresponding to the case q--> infinity, the XY model. Hence in terms of critical properties the limiting behavior is reached already at q=5.

Neuroleptic malignant syndrome in juvenile neuronal ceroid lipofuscinosis associated with low-dose risperidone therapy.

We present a patient with juvenile neuronal ceroid lipofuscinosis who developed a neuroleptic malignant syndrome when treated for hallucinations with a very low dose of risperidone, an atypical neuroleptic medication with usually few extrapyramidal side-effects. The loss of dopaminergic neurons in this condition may make these patients more vulnerable to this severe adverse effect.