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1.
Physiol Behav ; 220: 112862, 2020 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-32156558

RESUMO

Galectin-1 (Gal-1) and galectin-3 (Gal-3) are multifunctional glycan-binding proteins, expressed in the brain and in its limbic structures that are involved in behavioral control. Gal-1 induces the expression of the brain-derived neurotrophic factor (BDNF) and promotes adult neural stem cells proliferation, biological events impaired in stress-related psychiatric disorders, such as depression and anxiety. Despite that, there is no evidence regarding galectin involvement in emotional control during stressful situations. Thus, we analyzed the behavioral phenotype of Gal-1 or Gal-3 knock-out mice (Gal-1 KO or Gal-3 KO) in different experimental models predictive of depressive and compulsive-like behaviors. METHODS: C57BL-6 Gal-1 KO, Gal-3 KO, and wild-type mice (WT) were analyzed under the open field test (OFT) and, 6 h later, under the forced swim test (FST). Additionally, independent groups of male mice, lacking galectins or not, were exposed to the tail suspension test (TST) or to the marble burying test (MBT). The hippocampus and prefrontal cortex (PFC) of the mice submitted to MBT were dissected to access BDNF levels. RESULTS: Both Gal-1 and Gal-3 KO mice showed increased time of immobility in the FST and in the TST compared to WT animals, thus reflecting an impaired stress-coping behavior. Additionally, Gal-1 and Gal-3 KO female mice presented increased compulsive-like behavior in the MBT, without significant changes in the locomotor activity. BDNF levels were found to be decreased in the PFC of Gal-1 KO mice. DISCUSSION: Our results demonstrate that the absence of either endogenous Gal-1 and Gal-3 impairs stress-coping and increases compulsive-like behavior, suggesting that Gal-1 and Gal-3 are involved in the neurobiology of depression and obsessive-compulsive-like disorder.


Assuntos
Galectina 1 , Galectina 3 , Estresse Psicológico , Animais , Ansiedade , Comportamento Animal , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Comportamento Compulsivo , Depressão , Modelos Animais de Doenças , Emoções , Feminino , Galectina 1/genética , Galectina 3/genética , Hipocampo/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout
2.
J Neural Eng ; 13(5): 056016, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27619069

RESUMO

OBJECTIVE: Spinal cord injury causes a drastic loss of motor, sensory and autonomic function. The goal of this project was to investigate the use of intraspinal microstimulation (ISMS) for producing long distances of walking over ground. ISMS is an electrical stimulation method developed for restoring motor function by activating spinal networks below the level of an injury. It produces movements of the legs by stimulating the ventral horn of the lumbar enlargement using fine penetrating electrodes (≤50 µm diameter). APPROACH: In each of five adult cats (4.2-5.5 kg), ISMS was applied through 16 electrodes implanted with tips targeting lamina IX in the ventral horn bilaterally. A desktop system implemented a physiologically-based control strategy that delivered different stimulation patterns through groups of electrodes to evoke walking movements with appropriate limb kinematics and forces corresponding to swing and stance. Each cat walked over an instrumented 2.9 m walkway and limb kinematics and forces were recorded. MAIN RESULTS: Both propulsive and supportive forces were required for over-ground walking. Cumulative walking distances ranging from 609 to 835 m (longest tested) were achieved in three animals. In these three cats, the mean peak supportive force was 3.5 ± 0.6 N corresponding to full-weight-support of the hind legs, while the angular range of the hip, knee, and ankle joints were 23.1 ± 2.0°, 29.1 ± 0.2°, and 60.3 ± 5.2°, respectively. To further demonstrate the viability of ISMS for future clinical use, a prototype implantable module was successfully implemented in a subset of trials and produced comparable walking performance. SIGNIFICANCE: By activating inherent locomotor networks within the lumbosacral spinal cord, ISMS was capable of producing bilaterally coordinated and functional over-ground walking with current amplitudes <100 µA. These exciting results suggest that ISMS may be an effective intervention for restoring functional walking after spinal cord injury.


Assuntos
Estimulação Elétrica/métodos , Microeletrodos , Medula Espinal/fisiologia , Caminhada/fisiologia , Anestesia , Animais , Fenômenos Biomecânicos , Gatos , Estimulação Elétrica/instrumentação , Eletrodos Implantados , Extremidades/inervação , Extremidades/fisiologia , Membro Posterior/inervação , Membro Posterior/fisiologia , Locomoção/fisiologia , Fadiga Muscular/fisiologia , Rede Nervosa/fisiologia , Traumatismos da Medula Espinal/reabilitação
3.
Genes Immun ; 16(6): 378-87, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25996526

RESUMO

Inflammatory immune disorders such as inflammatory bowel disease and multiple sclerosis are major health problems. Currently, the intestinal whipworm Trichuris suis is being explored in clinical trials to reduce inflammation in these diseases; however, the mechanisms by which the parasite affects the host immune system are not known. Here we determined the effects of T. suis soluble products (SPs) on Toll-like receptor-4 (TLR4)-stimulated human dendritic cells (DCs) using Illumina bead chip gene arrays. Pathway analysis of lipopolysaccharide-stimulated DCs with or without T. suis treatment showed that co-stimulation with T. suis SPs resulted in a downregulation of both the myeloid differentiation primary response gene 88-dependent and the TIR-domain-containing adaptor-inducing interferon-ß-dependent signalling pathways triggered by TLR4. These data were verified using quantitative real-time PCR of several key genes within these pathways and/or defining their protein levels. In addition, T. suis SPs induce Rab7b, a negative regulator of TLR4 signalling that interferes with its trafficking, which coincided with a reduced surface expression of TLR4. These data indicate that the mechanism by which T. suis SPs reduce inflammatory responses is through suppression of both TLR4 signalling and surface expression on DCs.


Assuntos
Células Dendríticas/parasitologia , Receptor 4 Toll-Like/metabolismo , Trichuris/imunologia , Proteínas rab de Ligação ao GTP/metabolismo , Animais , Células Dendríticas/efeitos dos fármacos , Células Dendríticas/imunologia , Células Dendríticas/metabolismo , Regulação para Baixo , Humanos , Inflamação/imunologia , Inflamação/parasitologia , Inflamação/terapia , Lipopolissacarídeos/farmacologia , Reação em Cadeia da Polimerase em Tempo Real , Transdução de Sinais , Transcriptoma , proteínas de unión al GTP Rab7
4.
Am J Transplant ; 14(7): 1488-98, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24903539

RESUMO

Apoptosis is a programmed form of cell death whereby characteristic internal cellular dismantling is accompanied by the preservation of plasma membrane integrity. Maintaining this order during apoptosis prevents the release of cellular contents and ensures a noninflammatory death. Here, we consider examples of apoptosis in different contexts and discuss how the same form of cell death could have different immunological consequences. Multiple parameters such as cell death as a result of microbial infection, the nature of the inflammatory microenvironment, the type of responding phagocytic cells and the genetic background of the host organism all differentially influence the immunological consequences of apoptosis.


Assuntos
Apoptose/imunologia , Imunidade Inata/imunologia , Infecções/imunologia , Inflamação/imunologia , Transplante de Órgãos , Humanos , Infecções/patologia , Inflamação/patologia , Inflamação/prevenção & controle
5.
Biomater Sci ; 2(10): 1426-1439, 2014 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-26146546

RESUMO

The comparative dendritic cell (DC) response to glycoconjugates presented in soluble, phagocytosable, or non-phagocytosable display modalities is poorly understood. This is particularly problematic, as the probing of immobilized glycans presented on the surface of microarrays is a common screen for potential candidates for glycan-based therapeutics. However, the assumption that carbohydrate-protein interactions on a flat surface can be translatable to development of efficacious therapies, such as vaccines, which are delivered in soluble or phagocytosable particles, has not been validated. Thus, a preliminary investigation was performed in which mannose or glucose was conjugated to cationized bovine serum albumin and presented to DCs in soluble, phagocytosable, or non-phagocytosable display modalities. The functional DC response to the glycoconjugates was assessed via a high throughput assay. Dendritic cell phenotypic outcomes were placed into a multivariate, general linear model (GLM) and shown to be statistically different amongst display modalities when comparing similar surface areas. The GLM showed that glycoconjugates that were adsorbed to wells were the most pro-inflammatory while soluble conjugates were the least. DC interactions with mannose conjugates were found to be calcium dependent and could be inhibited via anti-DC-SIGN antibodies. The results of this study aim to resolve conflicts in reports from multiple laboratories showing differential DC profiles in response to similar, if not identical, ligands delivered via different modalities. Additionally, this study begins to bridge the gap between microarray binding data and functional cell responses by highlighting the phenotypes induced from adsorbed glycoconjugates as compared to those in solution or displayed on microparticles.

6.
Technol Health Care ; 20(5): 379-86, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23079943

RESUMO

Post operative retained foreign bodies are a rare but recalcitrant problem. We detail reports of interventions over the last two centuries and review the most current interventions using automated data identity capture and computer aided detection. This was one of earliest areas in which multidisciplinary collaboration was achieved in patient safety. This multidisciplinary collaboration was unique because most other initiatives had been internal: among the disciplines working in the OR i.e. surgeons, nurses and anesthesiologists; this collaboration, to achieve optimal patient safety at that point in time was between surgeons and radiologists to ensure a lack of post operative retained foreign bodies.


Assuntos
Tecnologia Biomédica/tendências , Corpos Estranhos/prevenção & controle , Complicações Pós-Operatórias/prevenção & controle , Diagnóstico por Computador , Corpos Estranhos/diagnóstico , Corpos Estranhos/etiologia , Humanos , Complicações Pós-Operatórias/diagnóstico , Complicações Pós-Operatórias/diagnóstico por imagem , Instrumentos Cirúrgicos , Tampões de Gaze Cirúrgicos , Tomografia Computadorizada por Raios X
7.
J Neural Eng ; 9(2): 026003, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22328615

RESUMO

The biological central pattern generator (CPG) integrates open and closed loop control to produce over-ground walking. The goal of this study was to develop a physiologically based algorithm capable of mimicking the biological system to control multiple joints in the lower extremities for producing over-ground walking. The algorithm used state-based models of the step cycle each of which produced different stimulation patterns. Two configurations were implemented to restore over-ground walking in five adult anaesthetized cats using intramuscular stimulation (IMS) of the main hip, knee and ankle flexor and extensor muscles in the hind limbs. An open loop controller relied only on intrinsic timing while a hybrid-CPG controller added sensory feedback from force plates (representing limb loading), and accelerometers and gyroscopes (representing limb position). Stimulation applied to hind limb muscles caused extension or flexion in the hips, knees and ankles. A total of 113 walking trials were obtained across all experiments. Of these, 74 were successful in which the cats traversed 75% of the 3.5 m over-ground walkway. In these trials, the average peak step length decreased from 24.9 ± 8.4 to 21.8 ± 7.5 (normalized units) and the median number of steps per trial increased from 7 (Q1 = 6, Q3 = 9) to 9 (8, 11) with the hybrid-CPG controller. Moreover, within these trials, the hybrid-CPG controller produced more successful steps (step length ≤ 20 cm; ground reaction force ≥ 12.5% body weight) than the open loop controller: 372 of 544 steps (68%) versus 65 of 134 steps (49%), respectively. This supports our previous preliminary findings, and affirms that physiologically based hybrid-CPG approaches produce more successful stepping than open loop controllers. The algorithm provides the foundation for a neural prosthetic controller and a framework to implement more detailed control of locomotion in the future.


Assuntos
Retroalimentação Fisiológica/fisiologia , Locomoção/fisiologia , Aceleração , Algoritmos , Anestesia , Animais , Fenômenos Biomecânicos , Gatos , Simulação por Computador , Estimulação Elétrica , Eletrodos Implantados , Eletromiografia , Membro Posterior/inervação , Membro Posterior/fisiologia , Instinto , Fadiga Muscular/fisiologia , Músculo Esquelético/fisiologia , Caminhada/fisiologia
8.
Future Med Chem ; 3(13): 1703-18, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21942257

RESUMO

Pressurized metered dose inhaler is the most common inhaled dosage form, ideally suited for delivering the highly potent compounds that medicinal chemists typically discover for respiratory therapeutic targets. The clinical benefit of combination therapy for asthma and chronic obstructive pulmonary disease has been well established, and many of the new discovery candidates are likely to be studied in the clinic as combination drugs even at early stages of development. We present a novel pressurized metered dose inhaler formulation approach to enable consistent aerosol performance of a respiratory therapeutic whether it is emitted from a single-, double- or triple-therapy product. This should enable rapid nonclinical and clinical assessment whether alone or in combination with other drugs, without the challenge of in vitro performance dissimilarity across product types.


Assuntos
Asma/tratamento farmacológico , Inaladores Dosimetrados , Doença Pulmonar Obstrutiva Crônica/tratamento farmacológico , Quimioterapia Combinada , Humanos
9.
Int J STD AIDS ; 21(11): 755-7, 2010 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-21187357

RESUMO

The proportion of clinically important diagnoses in a low-risk, asymptomatic population who use a computer-assisted self-interview (CASI) to assess risk was needed to determine optimal health service delivery. Medical records were retrospectively analysed between July 2008 and June 2009 for risk characteristics and diagnoses. A total of 7733 new patients completed a CASI, of whom 1060 were asymptomatic heterosexuals. From this low-risk group, 26 diagnoses were made on the day of presentation, including 22 cases of genital warts (2.08% [95% confidence interval (CI) 1.22-2.93]), three cases of genital herpes (0.28% [95% CI 0.055-0.82]) and one case of unintended pregnancy (0.094% [95% CI 0.0061-0.52]). Additionally, there were 54 cases of chlamydia detected (5.09% [95% CI 3.77-6.42]). As chlamydia is effectively diagnosed and managed from self-collected samples, patient review is not always required. This study provides evidence for an express testing service for chlamydia to streamline the screening of low-risk, asymptomatic heterosexual patients as identified by CASI without the need to for a traditional face-to-face consultation.


Assuntos
Infecções por Chlamydia/diagnóstico , Sistemas Computadorizados de Registros Médicos , Infecções Sexualmente Transmissíveis/diagnóstico , Adolescente , Adulto , Austrália/epidemiologia , Infecções por Chlamydia/epidemiologia , Feminino , Humanos , Entrevistas como Assunto , Masculino , Programas de Rastreamento/métodos , Encaminhamento e Consulta , Estudos Retrospectivos , Fatores de Risco , Comportamento Sexual , Infecções Sexualmente Transmissíveis/epidemiologia , Inquéritos e Questionários
10.
Int J STD AIDS ; 21(6): 428-30, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20606224

RESUMO

This study examined the views of 172 community-based Australian men who have sex with men (MSM) on the acceptability and potential uptake of rapid oral testing for HIV in clinic and home-based settings. Men were asked to complete a questionnaire that sought their views on rapid testing for HIV. When asked about which HIV test they would prefer in a clinic setting, 64% indicated a preference for rapid oral HIV testing and 74% indicated that if rapid oral HIV testing was available at a clinic they would test for HIV more frequently. If rapid oral HIV testing was available for home testing, 63% of men indicated it would be likely they would test themselves for HIV and 61% indicated they would test more frequently. Overall, MSM expressed a preference for rapid oral HIV testing and would test more frequently if testing was available for clinic or home use in Australia.


Assuntos
Infecções por HIV/diagnóstico , Homossexualidade Masculina , Aceitação pelo Paciente de Cuidados de Saúde , Adolescente , Adulto , Idoso , Austrália , Humanos , Masculino , Pessoa de Meia-Idade
11.
Artigo em Inglês | MEDLINE | ID: mdl-19964205

RESUMO

In order for the functionality of an upper-limb prosthesis to approach that of a real limb it must be able to, accurately and intuitively, convey sensory feedback to the limb user. This paper presents results of the real-time implementation of a 'biofidelic' model that describes mechanotransduction in Slowly Adapting Type 1 (SA1) afferent fibers. The model accurately predicts the timing of action potentials for arbitrary force or displacement stimuli and its output can be used as stimulation times for peripheral nerve stimulation by a neuroprosthetic device. The model performance was verified by comparing the predicted action potential (or spike) outputs against measured spike outputs for different vibratory stimuli. Furthermore experiments were conducted to show that, like real SA1 fibers, the model's spike rate varies according to input pressure and that a periodic 'tapping' stimulus evokes periodic spike outputs.


Assuntos
Vias Aferentes/fisiologia , Retroalimentação Fisiológica/fisiologia , Modelos Neurológicos , Sistema Nervoso Periférico/fisiologia , Fenômenos Fisiológicos da Pele , Pele/inervação , Tato/fisiologia , Simulação por Computador , Sistemas Computacionais , Humanos
12.
Angiology ; 60(4): 492-5, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19398420

RESUMO

Venous leg ulcers are common, chronic, debilitating, and expensive. Evidence supports use of compression bandaging, with superficial venous surgery in selected cases, but these interventions frequently fail to achieve healing. We describe a series of 152 consecutive referrals from a nurse-led specialist dermatology clinic to a vascular surgical service; a group posing particularly challenging problems. This observational study, with median follow-up of 18 months, describes outcomes in a number of important clinically identifiable subgroups. Its findings may assist service planning and discussion of the surgical role within multidisciplinary ulcer management.


Assuntos
Encaminhamento e Consulta , Escleroterapia , Meias de Compressão , Úlcera Varicosa/terapia , Procedimentos Cirúrgicos Vasculares , Cicatrização , Adulto , Idoso , Idoso de 80 Anos ou mais , Doença Crônica , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Procedimentos Cirúrgicos Minimamente Invasivos , Reoperação , Fatores de Tempo , Falha de Tratamento , Resultado do Tratamento , Úlcera Varicosa/diagnóstico , Úlcera Varicosa/fisiopatologia , Úlcera Varicosa/cirurgia
13.
Int J STD AIDS ; 20(3): 165-7, 2009 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-19255262

RESUMO

The aim of this study was to determine the experience and views of female patients when they were offered a chaperone by a male sexual health practitioner for a genital examination. Between November 2007 and January 2008, an anonymous survey was administered to female patients seen by male practitioners at Melbourne Sexual Health Centre. None of the 79 (95% CI 0-5%) patients who were offered a chaperone and declined one reported that they were uncomfortable declining the offer. The qualitative analysis showed that some participants appreciated being offered the option of a chaperone even if they did not want one and that the professional attributes of the practitioner influenced their decision not to have a chaperone. Only 8% (95%CI 4-15%) felt uncomfortable when asked if they would like a chaperone. The results reassure that when a female patient declines the offer of a chaperone within a sexual health clinic, the male practitioner can feel confident that this is the expression of the patient's wish.


Assuntos
Instituições de Assistência Ambulatorial , Doenças dos Genitais Femininos/diagnóstico , Relações Enfermeiro-Paciente , Aceitação pelo Paciente de Cuidados de Saúde/psicologia , Satisfação do Paciente , Exame Físico , Relações Médico-Paciente , Adulto , Atitude do Pessoal de Saúde , Estudos Transversais , Feminino , Humanos , Masculino , Inquéritos e Questionários
14.
Int J STD AIDS ; 19(9): 581-5, 2008 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-18725546

RESUMO

The aim of this study was to ascertain how sexual health physicians in Australia and New Zealand manage men with chlamydia-negative non-gonococcal urethritis (NGU), particularly in relation to the notification of their female sexual partners. In July 2006, a cross-section survey was sent out to all the members of the Australasian Chapter of Sexual Health Medicine. Seventy-three percent of sexual health physicians believed that female partners of men who present with chlamydia-negative NGU were at risk of adverse reproductive health outcomes. At least 62% usually initiated some form of partner notification of female partners of men with chlamydia-negative NGU. However, only 19% (21/111) of sexual health physicians routinely tested for, and only 65% sometimes tested for, pathogens other than Neisseria gonorrhoeae and Chlamydia trachomatis in men presenting with NGU. These included Mycoplasma genitalium, herpes simplex virus, ureaplasma species, Trichomonas vaginalis and adenoviruses.


Assuntos
Busca de Comunicante , Uretrite , Australásia , Estudos Transversais , Feminino , Doenças dos Genitais Femininos/epidemiologia , Doenças dos Genitais Femininos/prevenção & controle , Humanos , Masculino , Gravidez , Complicações Infecciosas na Gravidez/epidemiologia , Complicações Infecciosas na Gravidez/prevenção & controle , Risco , Uretrite/epidemiologia , Uretrite/microbiologia , Uretrite/parasitologia , Uretrite/virologia
15.
Pediatrics ; 121(5): 890-7, 2008 May.
Artigo em Inglês | MEDLINE | ID: mdl-18450891

RESUMO

OBJECTIVE: We performed a case-control study to determine whether occult bone disease is associated with a history of frequent fractures in children. METHODS: Healthy children with > or = 2 incidences of low-energy fractures were recruited (n = 68). Children with no history of fractures served as control subjects (n = 57). Food logs, activity surveys, physical examinations, laboratory tests, and dual-energy radiographic absorptiometry were used. RESULTS: Bone mineral density z scores were significantly reduced in case subjects, compared with control subjects. Three case subjects (4.3%) and 1 control subject (1.8%) had bone mineral density z scores below the expected range. Of those 4 subjects, 2 had dairy avoidance and 2 had delayed puberty. An additional case subject had evidence of vitamin D deficiency. A significant number of subjects (20% of case subjects and 23% of control subjects) had idiopathic hypercalcuria, based on 24-hour urine collections. Among the case subjects, bone mineral density z scores were significantly lower for those with idiopathic hypercalcuria. Among the control subjects, the presence of idiopathic hypercalcuria did not affect bone mineral density. The case subjects with idiopathic hypercalcuria accounted for virtually all of the differences in bone mineral density between the case and control groups. Analysis of parathyroid hormone and 1,25-dihydroxy-vitamin D levels showed that children with frequent fractures and hypercalcuria had renal hypercalcuria, whereas children with no fractures and hypercalcuria had absorptive hypercalcuria. CONCLUSIONS: We identified a significant association between a history of frequent fractures and hypercalcuria in children. We propose that the appropriate screening evaluation for children who present with a history of frequent fractures consists of a dietary history targeted at calcium and vitamin D intakes, a physical examination to assess for pubertal delay, and urinary calcium concentration/creatinine ratio determination to assess for hypercalcuria. Children with abnormalities in this screening should undergo dual-energy radiographic absorptiometry and appropriate evaluation.


Assuntos
Doenças Ósseas Metabólicas/diagnóstico , Fraturas Ósseas/etiologia , Absorciometria de Fóton , Adolescente , Densidade Óssea , Doenças Ósseas Metabólicas/complicações , Cálcio/urina , Criança , Pré-Escolar , Dieta , Exercício Físico , Feminino , Humanos , Masculino , Deficiência de Vitamina D
17.
IEEE Trans Biomed Circuits Syst ; 2(3): 212-22, 2008 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23852970

RESUMO

We present a neuromorphic silicon chip that emulates the activity of the biological spinal central pattern generator (CPG) and creates locomotor patterns to support walking. The chip implements ten integrate-and-fire silicon neurons and 190 programmable digital-to-analog converters that act as synapses. This architecture allows for each neuron to make synaptic connections to any of the other neurons as well as to any of eight external input signals and one tonic bias input. The chip's functionality is confirmed by a series of experiments in which it controls the motor output of a paralyzed animal in real-time and enables it to walk along a three-meter platform. The walking is controlled under closed-loop conditions with the aide of sensory feedback that is recorded from the animal's legs and fed into the silicon CPG. Although we and others have previously described biomimetic silicon locomotor control systems for robots, this is the first demonstration of a neuromorphic device that can replace some functions of the central nervous system in vivo.

19.
Mol Pharm ; 3(5): 516-24, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-17009850

RESUMO

Contrast-enhanced ultrasound imaging has shown promise in the field of molecular imaging. This technique relies upon the adhesion of ultrasound contrast agent (UCA) to targeted molecular markers of disease. This is accomplished by coating the surface of the contrast agent with a ligand that specifically binds to the intended molecular marker. Most UCA particles remain in the blood space, and their retention is influenced by the forces imposed by blood flow. For a UCA bound to a molecular target on the vascular endothelium, blood flow imposes a dislodging force that counteracts retention. Additionally, contrast agent adhesion to the molecular marker requires rapid binding kinetics, especially in rapid blood flow. The ability of a ligand:target bond complex to mediate fast adhesion and withstand dislodging force is necessary for efficient ultrasound-based molecular imaging. In the current study, we describe a flow-based adhesion assay which, combined with a novel automated tracking algorithm, enables quick determination of the ability of a targeting ligand to mediate effective contrast agent adhesion. This system was used to explore the adhesion of UCA targeted to the proinflammatory endothelial protein P-selectin via four targeting ligands, which revealed several interesting adhesive behaviors. Contrast agents targeted with glycoconjugate ligands modeled on P-selectin glycoprotein ligand 1 exhibited primarily unstable or transient adhesion, while UCA targeted with an anti-P-selectin monoclonal antibody exhibited primarily firm adhesion, although the efficiency with which these agents were recruited to the target surface was relatively low.


Assuntos
Meios de Contraste/metabolismo , Glicoconjugados/metabolismo , Selectina-P/metabolismo , Adesividade , Algoritmos , Animais , Anticorpos Monoclonais/química , Anticorpos Monoclonais/metabolismo , Meios de Contraste/química , Glicoconjugados/química , Cinética , Ligantes , Camundongos , Microbolhas , Selectina-P/química , Selectina-P/imunologia , Ligação Proteica , Resistência ao Cisalhamento , Ultrassom
20.
J Neural Transm (Vienna) ; 113(9): 1243-51, 2006 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-16362635

RESUMO

Cerebral beta-amyloidosis was found in 16/18 marmosets aged <10 yrs and 8/9 marmosets aged >10 yrs, injected intracerebrally with human or marmoset brain homogenate containing beta-amyloid 1-8 years previously. It was found in only 2/12 marmosets aged <10 yrs and 1/15 marmosets aged >10 yrs, injected with synthetic Abeta-peptides, CSF, or brain tissue which did not contain beta-amyloid. Cerebral beta-amyloidosis was found in 0/11 uninjected marmosets aged <10 yrs and in 5/29 uninjected marmosets aged >10 yrs. The beta-amyloidosis comprised small and large vessel angiopathy and some plaques throughout cortex and was qualitatively similar in injected marmosets and, when present, in uninjected marmosets. Of those injected marmosets which were positive, the amount of beta-amyloidosis was unrelated to age or incubation times but the 3 injected marmosets without beta-amyloidosis had incubation times of <3.5 years. We conclude that beta-amyloid, or associated factors, can initiate or accelerate the process of cerebral amyloidosis in primates.


Assuntos
Peptídeos beta-Amiloides/metabolismo , Amiloidose/patologia , Adulto , Envelhecimento/metabolismo , Envelhecimento/patologia , Peptídeos beta-Amiloides/líquido cefalorraquidiano , Peptídeos beta-Amiloides/toxicidade , Amiloidose/induzido quimicamente , Amiloidose/metabolismo , Animais , Encéfalo/metabolismo , Encéfalo/patologia , Encéfalo/fisiologia , Callithrix , Síndrome de Down/metabolismo , Feminino , Doença de Gerstmann-Straussler-Scheinker/metabolismo , Humanos , Masculino , Pessoa de Meia-Idade , Fragmentos de Peptídeos/toxicidade
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