A simple, validated protocol consisting of a battery of tests is available to identify elderly patients with frailty syndrome. This syndrome of decreased reserve and resistance to stressors increases in incidence with increasing age. In the elderly, frailty may pursue a step-wise loss of function from non-frail to pre-frail to frail. We studied frailty in HIV-infected patients and found that ~20% are frail using the Fried phenotype using stringent criteria developed for the elderly1,2. In HIV infection the syndrome occurs at a younger age.
HIV patients were checked for 1) unintentional weight loss; 2) slowness as determined by walking speed; 3) weakness as measured by a grip dynamometer; 4) exhaustion by responses to a depression scale; and 5) low physical activity was determined by assessing kilocalories expended in a week's time. Pre-frailty was present with any two of five criteria and frailty was present if any three of the five criteria were abnormal.
The tests take approximately 10-15 min to complete and they can be performed by medical assistants during routine clinic visits. Test results are scored by referring to standard tables. Understanding which of the five components contribute to frailty in an individual patient can allow the clinician to address relevant underlying problems, many of which are not evident in routine HIV clinic visits.
20 Related JoVE Articles!
An Affordable HIV-1 Drug Resistance Monitoring Method for Resource Limited Settings
Institutions: University of KwaZulu-Natal, Durban, South Africa, Jembi Health Systems, University of Amsterdam, Stanford Medical School.
HIV-1 drug resistance has the potential to seriously compromise the effectiveness and impact of antiretroviral therapy (ART). As ART programs in sub-Saharan Africa continue to expand, individuals on ART should be closely monitored for the emergence of drug resistance. Surveillance of transmitted drug resistance to track transmission of viral strains already resistant to ART is also critical. Unfortunately, drug resistance testing is still not readily accessible in resource limited settings, because genotyping is expensive and requires sophisticated laboratory and data management infrastructure. An open access genotypic drug resistance monitoring method to manage individuals and assess transmitted drug resistance is described. The method uses free open source software for the interpretation of drug resistance patterns and the generation of individual patient reports. The genotyping protocol has an amplification rate of greater than 95% for plasma samples with a viral load >1,000 HIV-1 RNA copies/ml. The sensitivity decreases significantly for viral loads <1,000 HIV-1 RNA copies/ml. The method described here was validated against a method of HIV-1 drug resistance testing approved by the United States Food and Drug Administration (FDA), the Viroseq genotyping method. Limitations of the method described here include the fact that it is not automated and that it also failed to amplify the circulating recombinant form CRF02_AG from a validation panel of samples, although it amplified subtypes A and B from the same panel.
Medicine, Issue 85, Biomedical Technology, HIV-1, HIV Infections, Viremia, Nucleic Acids, genetics, antiretroviral therapy, drug resistance, genotyping, affordable
Simultaneous Quantification of T-Cell Receptor Excision Circles (TRECs) and K-Deleting Recombination Excision Circles (KRECs) by Real-time PCR
Institutions: Spedali Civili di Brescia.
T-cell receptor excision circles (TRECs) and K-deleting recombination excision circles (KRECs) are circularized DNA elements formed during recombination process that creates T- and B-cell receptors. Because TRECs and KRECs are unable to replicate, they are diluted after each cell division, and therefore persist in the cell. Their quantity in peripheral blood can be considered as an estimation of thymic and bone marrow output. By combining well established and commonly used TREC assay with a modified version of KREC assay, we have developed a duplex quantitative real-time PCR that allows quantification of both newly-produced T and B lymphocytes in a single assay. The number of TRECs and KRECs are obtained using a standard curve prepared by serially diluting TREC and KREC signal joints cloned in a bacterial plasmid, together with a fragment of T-cell receptor alpha constant gene that serves as reference gene. Results are reported as number of TRECs and KRECs/106
cells or per ml of blood. The quantification of these DNA fragments have been proven useful for monitoring immune reconstitution following bone marrow transplantation in both children and adults, for improved characterization of immune deficiencies, or for better understanding of certain immunomodulating drug activity.
Immunology, Issue 94, B lymphocytes, primary immunodeficiency, real-time PCR, immune recovery, T-cell homeostasis, T lymphocytes, thymic output, bone marrow output
Quantitative Assessment of Cortical Auditory-tactile Processing in Children with Disabilities
Institutions: Vanderbilt University, Vanderbilt University, Vanderbilt University.
Objective and easy measurement of sensory processing is extremely difficult in nonverbal or vulnerable pediatric patients. We developed a new methodology to quantitatively assess children's cortical processing of light touch, speech sounds and the multisensory processing of the 2 stimuli, without requiring active subject participation or causing children discomfort. To accomplish this we developed a dual channel, time and strength calibrated air puff stimulator that allows both tactile stimulation and sham control. We combined this with the use of event-related potential methodology to allow for high temporal resolution of signals from the primary and secondary somatosensory cortices as well as higher order processing. This methodology also allowed us to measure a multisensory response to auditory-tactile stimulation.
Behavior, Issue 83, somatosensory, event related potential, auditory-tactile, multisensory, cortical response, child
Rapid Screening of HIV Reverse Transcriptase and Integrase Inhibitors
Institutions: National Cancer Institute.
Although a number of anti HIV drugs have been approved, there are still problems with toxicity and drug resistance. This demonstrates a need to identify new compounds that can inhibit infection by the common drug resistant HIV-1 strains with minimal toxicity. Here we describe an efficient assay that can be used to rapidly determine the cellular cytotoxicity and efficacy of a compound against WT and mutant viral strains.
The desired target cell line is seeded in a 96-well plate and, after a 24 hr incubation, serially dilutions of the compounds to be tested are added. No further manipulations are necessary for cellular cytotoxicity assays; for anti HIV assays a predetermined amount of either a WT or drug resistant HIV-1 vector that expresses luciferase is added to the cells. Cytotoxicity is measured by using an ATP dependent luminescence assay and the impact of the compounds on infectivity is measured by determining the amount of luciferase in the presence or the absence of the putative inhibitors.
This screening assay takes 4 days to complete and multiple compounds can be screened in parallel. Compounds are screened in triplicate and the data are normalized to the infectivity/ATP levels in absence of target compounds. This technique provides a quick and accurate measurement of the efficacy and toxicity of potential anti HIV compounds.
Immunology, Issue 86, HIV, cytotoxicity, infectivity, luciferase, drug resistance, integrase, reverse transcriptase
Development of an IFN-γ ELISpot Assay to Assess Varicella-Zoster Virus-specific Cell-mediated Immunity Following Umbilical Cord Blood Transplantation
Institutions: Université de Montréal, Université de Montréal, Université de Montréal.
Varicella zoster virus (VZV) is a significant cause of morbidity and mortality following umbilical cord blood transplantation (UCBT). For this reason, antiherpetic prophylaxis is administrated systematically to pediatric UCBT recipients to prevent complications associated with VZV infection, but there is no strong, evidence based consensus that defines its optimal duration. Because T cell mediated immunity is responsible for the control of VZV infection, assessing the reconstitution of VZV specific T cell responses following UCBT could provide indications as to whether prophylaxis should be maintained or can be discontinued. To this end, a VZV specific gamma interferon (IFN-γ) enzyme-linked immunospot (ELISpot) assay was developed to characterize IFN-γ production by T lymphocytes in response to in vitro
stimulation with irradiated live attenuated VZV vaccine. This assay provides a rapid, reproducible and sensitive measurement of VZV specific cell mediated immunity suitable for monitoring the reconstitution of VZV specific immunity in a clinical setting and assessing immune responsiveness to VZV antigens.
Immunology, Issue 89, Varicella zoster virus, cell-mediated immunity, T cells, interferon gamma, ELISpot, umbilical cord blood transplantation
Cortical Source Analysis of High-Density EEG Recordings in Children
Institutions: UCL Institute of Child Health, University College London.
EEG is traditionally described as a neuroimaging technique with high temporal and low spatial resolution. Recent advances in biophysical modelling and signal processing make it possible to exploit information from other imaging modalities like structural MRI that provide high spatial resolution to overcome this constraint1
. This is especially useful for investigations that require high resolution in the temporal as well as spatial domain. In addition, due to the easy application and low cost of EEG recordings, EEG is often the method of choice when working with populations, such as young children, that do not tolerate functional MRI scans well. However, in order to investigate which neural substrates are involved, anatomical information from structural MRI is still needed. Most EEG analysis packages work with standard head models that are based on adult anatomy. The accuracy of these models when used for children is limited2
, because the composition and spatial configuration of head tissues changes dramatically over development3
In the present paper, we provide an overview of our recent work in utilizing head models based on individual structural MRI scans or age specific head models to reconstruct the cortical generators of high density EEG. This article describes how EEG recordings are acquired, processed, and analyzed with pediatric populations at the London Baby Lab, including laboratory setup, task design, EEG preprocessing, MRI processing, and EEG channel level and source analysis.
Behavior, Issue 88, EEG, electroencephalogram, development, source analysis, pediatric, minimum-norm estimation, cognitive neuroscience, event-related potentials
Zinc-finger Nuclease Enhanced Gene Targeting in Human Embryonic Stem Cells
Institutions: Monash University.
One major limitation with current human embryonic stem cell (ESC) differentiation protocols is the generation of heterogeneous cell populations. These cultures contain the cells of interest, but are also contaminated with undifferentiated ESCs, non-neural derivatives and other neuronal subtypes. This limits their use in in vitro
and in vivo
applications, such as in vitro
modeling for drug discovery or cell replacement therapy. To help overcome this, reporter cell lines, which offer a means to visualize, track and isolate cells of interest, can be engineered. However, to achieve this in human embryonic stem cells via conventional homologous recombination is extremely inefficient. This protocol describes targeting of the Pituitary homeobox 3
) locus in human embryonic stem cells using custom designed zinc-finger nucleases, which introduce site-specific double-strand DNA breaks, together with a PITX3
-specific DNA donor vector. Following the generation of the PITX3
reporter cell line, it can then be differentiated using published protocols for use in studies such as in vitro
Parkinson’s disease modeling or cell replacement therapy.
Molecular Biology, Issue 90, Electroporation, human embryonic stem cell, genome editing, reporter cell line, midbrain dopaminergic neurons
Community-based Adapted Tango Dancing for Individuals with Parkinson's Disease and Older Adults
Institutions: Emory University School of Medicine, Brigham and Woman‘s Hospital and Massachusetts General Hospital.
Adapted tango dancing improves mobility and balance in older adults and additional populations with balance impairments. It is composed of very simple step elements. Adapted tango involves movement initiation and cessation, multi-directional perturbations, varied speeds and rhythms. Focus on foot placement, whole body coordination, and attention to partner, path of movement, and aesthetics likely underlie adapted tango’s demonstrated efficacy for improving mobility and balance. In this paper, we describe the methodology to disseminate the adapted tango teaching methods to dance instructor trainees and to implement the adapted tango by the trainees in the community for older adults and individuals with Parkinson’s Disease (PD). Efficacy in improving mobility (measured with the Timed Up and Go, Tandem stance, Berg Balance Scale, Gait Speed and 30 sec chair stand), safety and fidelity of the program is maximized through targeted instructor and volunteer training and a structured detailed syllabus outlining class practices and progression.
Behavior, Issue 94, Dance, tango, balance, pedagogy, dissemination, exercise, older adults, Parkinson's Disease, mobility impairments, falls
The Goeckerman Regimen for the Treatment of Moderate to Severe Psoriasis
Institutions: University of Southern California, University of California, San Francisco , University of California Irvine School of Medicine, University of Arizona College of Medicine, Chicago College of Osteopathic Medicine.
Psoriasis is a chronic, immune-mediated inflammatory skin disease affecting approximately 2-3% of the population. The Goeckerman regimen consists of exposure to ultraviolet B (UVB) light and application of crude coal tar (CCT). Goeckerman therapy is extremely effective and relatively safe for the treatment of psoriasis and for improving a patient's quality of life. In the following article, we present our protocol for the Goeckerman therapy that is utilized specifically at the University of California, San Francisco. This protocol details the preparation of supplies, administration of phototherapy and application of topical tar. This protocol also describes how to assess the patient daily, monitor for adverse effects (including pruritus and burning), and adjust the treatment based on the patient's response. Though it is one of the oldest therapies available for psoriasis, there is an absence of any published videos demonstrating the process in detail. The video is beneficial for healthcare providers who want to administer the therapy, for trainees who want to learn more about the process, and for prospective patients who want to undergo treatment for their cutaneous disease.
Medicine, Issue 77, Infection, Biomedical Engineering, Anatomy, Physiology, Immunology, Dermatology, Skin, Dermis, Epidermis, Skin Diseases, Skin Diseases, Eczematous, Goeckerman, Crude Coal Tar, phototherapy, psoriasis, Eczema, Goeckerman regimen, clinical techniques
Setting Limits on Supersymmetry Using Simplified Models
Institutions: University College London, CERN, Lawrence Berkeley National Laboratories.
Experimental limits on supersymmetry and similar theories are difficult to set because of the enormous available parameter space and difficult to generalize because of the complexity of single points. Therefore, more phenomenological, simplified models are becoming popular for setting experimental limits, as they have clearer physical interpretations. The use of these simplified model limits to set a real limit on a concrete theory has not, however, been demonstrated. This paper recasts simplified model limits into limits on a specific and complete supersymmetry model, minimal supergravity. Limits obtained under various physical assumptions are comparable to those produced by directed searches. A prescription is provided for calculating conservative and aggressive limits on additional theories. Using acceptance and efficiency tables along with the expected and observed numbers of events in various signal regions, LHC experimental results can be recast in this manner into almost any theoretical framework, including nonsupersymmetric theories with supersymmetry-like signatures.
Physics, Issue 81, high energy physics, particle physics, Supersymmetry, LHC, ATLAS, CMS, New Physics Limits, Simplified Models
Portable Intermodal Preferential Looking (IPL): Investigating Language Comprehension in Typically Developing Toddlers and Young Children with Autism
Institutions: University of Connecticut.
One of the defining characteristics of autism spectrum disorder (ASD) is difficulty with language and communication.1
Children with ASD's onset of speaking is usually delayed, and many children with ASD consistently produce language less frequently and of lower lexical and grammatical complexity than their typically developing (TD) peers.6,8,12,23
However, children with ASD also exhibit a significant social deficit, and researchers and clinicians continue to debate the extent to which the deficits in social interaction account for or contribute to the deficits in language production.5,14,19,25
Standardized assessments of language in children with ASD usually do include a comprehension component; however, many such comprehension tasks assess just one aspect of language (e.g.
or include a significant motor component (e.g.
, pointing, act-out), and/or require children to deliberately choose between a number of alternatives. These last two behaviors are known to also be challenging to children with ASD.7,12,13,16
We present a method which can assess the language comprehension of young typically developing children (9-36 months) and children with autism.2,4,9,11,22
This method, Portable Intermodal Preferential Looking (P-IPL), projects side-by-side video images from a laptop onto a portable screen. The video images are paired first with a 'baseline' (nondirecting) audio, and then presented again paired with a 'test' linguistic audio that matches only one of the video images. Children's eye movements while watching the video are filmed and later coded. Children who understand the linguistic audio will look more quickly to, and longer at, the video that matches the linguistic audio.2,4,11,18,22,26
This paradigm includes a number of components that have recently been miniaturized (projector, camcorder, digitizer) to enable portability and easy setup in children's homes. This is a crucial point for assessing young children with ASD, who are frequently uncomfortable in new (e.g.
, laboratory) settings. Videos can be created to assess a wide range of specific components of linguistic knowledge, such as Subject-Verb-Object word order, wh-questions, and tense/aspect suffixes on verbs; videos can also assess principles of word learning such as a noun bias, a shape bias, and syntactic bootstrapping.10,14,17,21,24
Videos include characters and speech that are visually and acoustically salient and well tolerated by children with ASD.
Medicine, Issue 70, Neuroscience, Psychology, Behavior, Intermodal preferential looking, language comprehension, children with autism, child development, autism
A Novel Rescue Technique for Difficult Intubation and Difficult Ventilation
Institutions: Children’s Hospital of Michigan, St. Jude Children’s Research Hospital.
We describe a novel non surgical technique to maintain oxygenation and ventilation in a case of difficult intubation and difficult ventilation, which works especially well with poor mask fit.
Can not intubate, can not ventilate" (CICV) is a potentially life threatening situation. In this video we present a simulation of the technique we used in a case of CICV where oxygenation and ventilation were maintained by inserting an endotracheal tube (ETT) nasally down to the level of the naso-pharynx while sealing the mouth and nares for successful positive pressure ventilation.
A 13 year old patient was taken to the operating room for incision and drainage of a neck abcess and direct laryngobronchoscopy. After preoxygenation, anesthesia was induced intravenously. Mask ventilation was found to be extremely difficult because of the swelling of the soft tissue. The face mask could not fit properly on the face due to significant facial swelling as well. A direct laryngoscopy was attempted with no visualization of the larynx. Oxygen saturation was difficult to maintain, with saturations falling to 80%. In order to oxygenate and ventilate the patient, an endotracheal tube was then inserted nasally after nasal spray with nasal decongestant and lubricant. The tube was pushed gently and blindly into the hypopharynx. The mouth and nose of the patient were sealed by hand and positive pressure ventilation was possible with 100% O2
with good oxygen saturation during that period of time. Once the patient was stable and well sedated, a rigid bronchoscope was introduced by the otolaryngologist showing extensive subglottic and epiglottic edema, and a mass effect from the abscess, contributing to the airway compromise. The airway was secured with an ETT tube by the otolaryngologist.This video will show a simulation of the technique on a patient undergoing general anesthesia for dental restorations.
Medicine, Issue 47, difficult ventilation, difficult intubation, nasal, saturation
Measurement Of Neuromagnetic Brain Function In Pre-school Children With Custom Sized MEG
Institutions: Macquarie University.
Magnetoencephalography is a technique that detects magnetic fields associated with cortical activity . The electrophysiological activity of the brain generates electric fields - that can be recorded using electroencephalography (EEG)- and their concomitant magnetic fields - detected by MEG. MEG signals are detected by specialized sensors known as superconducting quantum interference devices (SQUIDs). Superconducting sensors require cooling with liquid helium at -270 °C. They are contained inside a vacumm-insulated helmet called a dewar, which is filled with liquid. SQUIDS are placed in fixed positions inside the helmet dewar in the helium coolant, and a subject's head is placed inside the helmet dewar for MEG measurements. The helmet dewar must be sized to satisfy opposing constraints. Clearly, it must be large enough to fit most or all of the heads in the population that will be studied. However, the helmet must also be small enough to keep most of the SQUID sensors within range of the tiny cerebral fields that they are to measure. Conventional whole-head MEG systems are designed to accommodate more than 90% of adult heads. However adult systems are not well suited for measuring brain function in pre-school chidren whose heads have a radius several cm smaller than adults. The KIT-Macquarie Brain Research Laboratory at Macquarie University uses a MEG system custom sized to fit the heads of pre-school children. This child system has 64 first-order axial gradiometers with a 50 mm baseline and is contained inside a magnetically-shielded room (MSR) together with a conventional adult-sized MEG system [3,4]. There are three main advantages of the customized helmet dewar for studying children. First, the smaller radius of the sensor configuration brings the SQUID sensors into range of the neuromagnetic signals of children's heads. Second, the smaller helmet allows full insertion of a child's head into the dewar. Full insertion is prevented in adult dewar helmets because of the smaller crown to shoulder distance in children. These two factors are fundamental in recording brain activity using MEG because neuromagnetic signals attenuate rapidly with distance. Third, the customized child helmet aids in the symmetric positioning of the head and limits the freedom of movement of the child's head within the dewar. When used with a protocol that aligns the requirements of data collection with the motivational and behavioral capacities of children, these features significantly facilitate setup, positioning, and measurement of MEG signals.
Neuroscience, Issue 36, Magnetoencephalography, Pediatrics, Brain Mapping, Language, Brain Development, Cognitive Neuroscience, Language Acquisition, Linguistics
Guidelines for Elective Pediatric Fiberoptic Intubation
Institutions: St. Jude Children's Research Hospital, Children's Hospital of Michigan, Children's Hospital of Michigan.
Fiberoptic intubation in pediatric patients is often required especially in difficult airways of syndromic patients i.e. Pierre Robin Syndrome. Small babies will desaturate very quickly if ventilation is interrupted mainly to high metabolic rate. We describe guidelines to perform a safe fiberoptic intubation while maintaining spontaneous breathing throughout the procedure. Steps requiring the use of propofol pump, fentanyl, glycopyrrolate, red rubber catheter, metal insuflation hook, afrin, lubricant and lidocaine spray are shown.
Medicine, Issue 47, Fiberoptic, Intubation, Pediatric, elective
Methods Development for Blood Borne Macrophage Carriage of Nanoformulated Antiretroviral Drugs
Institutions: University of Nebraska Medical Center.
Nanoformulated drugs can improve pharmacodynamics and bioavailability while serving also to reduce drug toxicities for antiretroviral (ART) medicines. To this end, our laboratory has applied the principles of nanomedicine to simplify ART regimens and as such reduce toxicities while improving compliance and drug pharmacokinetics. Simple and reliable methods for manufacturing nanoformulated ART (nanoART) are shown. Particles of pure drug are encapsulated by a thin layer of surfactant lipid coating and produced by fractionating larger drug crystals into smaller ones by either wet milling or high-pressure homogenization. In an alternative method free drug is suspended in a droplet of a polymer. Herein, drug is dissolved within a polymer then agitated by ultrasonication until individual nanosized droplets are formed. Dynamic light scattering and microscopic examination characterize the physical properties of the particles (particle size, charge and shape). Their biologic properties (cell uptake and retention, cytotoxicity and antiretroviral efficacy) are determined with human monocyte-derived macrophages (MDM). MDM are derived from human peripheral blood monocytes isolated from leukopacks using centrifugal elutriation for purification. Such blood-borne macrophages may be used as cellular transporters for nanoART distribution to human immunodeficiency virus (HIV) infected organs. We posit that the repackaging of clinically available antiretroviral medications into nanoparticles for HIV-1 treatments may improve compliance and positively affect disease outcomes.
Immunology, Issue 46, NanoART, antiretroviral, HIV/AIDS, monocytes/macrophages, wet milling, homogenization, ultrasonication
Amplifying and Quantifying HIV-1 RNA in HIV Infected Individuals with Viral Loads Below the Limit of Detection by Standard Clinical Assays
Institutions: NCI-Frederick, University of Pittsburgh, Tuffts University.
Amplifying viral genes and quantifying HIV-1 RNA in HIV-1 infected individuals with viral loads below the limit of detection by standard assays (below 50-75 copies/ml) is necessary to gain insight to viral dynamics and virus host interactions in patients who naturally control the infection and those who are on combination antiretroviral therapy (cART).
Here we describe how to amplify viral genomes by single genome sequencing (the SGS protocol) 13, 19
and how to accurately quantify HIV-1 RNA in patients with low viral loads (the single-copy assay (SCA) protocol) 12, 20
The single-copy assay is a real-time PCR assay with sensitivity depending on the volume of plasma being assayed. If a single virus genome is detected in 7 ml of plasma, then the RNA copy number is reported to be 0.3 copies/ml. The assay has an internal control testing for the efficiency of RNA extraction, and controls for possible amplification from DNA or contamination. Patient samples are measured in triplicate.
The single-genome sequencing assay (SGS), now widely used and considered to be non-labor intensive 3, 7, 12, 14, 15
,is a limiting dilution assay, in which endpoint diluted cDNA product is spread over a 96-well plate. According to a Poisson distribution, when less than 1/3 of the wells give product, there is an 80% chance of the PCR product being resultant of amplification from a single cDNA molecule. SGS has the advantage over cloning of not being subjected to resampling and not being biased by PCR-introduced recombination 19
. However, the amplification success of SCA and SGS depend on primer design. Both assays were developed for HIV-1 subtype B, but can be adapted for other subtypes and other regions of the genome by changing primers, probes, and standards.
Immunology, Issue 55, single genome sequencing, SGS, real-time PCR, single-copy assay, SCA, HIV-1, ultra-sensitive, RNA extraction
Eye Tracking Young Children with Autism
Institutions: University of Texas at Dallas, University of North Carolina at Chapel Hill.
The rise of accessible commercial eye-tracking systems has fueled a rapid increase in their use in psychological and psychiatric research. By providing a direct, detailed and objective measure of gaze behavior, eye-tracking has become a valuable tool for examining abnormal perceptual strategies in clinical populations and has been used to identify disorder-specific characteristics1
, promote early identification2
, and inform treatment3
. In particular, investigators of autism spectrum disorders (ASD) have benefited from integrating eye-tracking into their research paradigms4-7
. Eye-tracking has largely been used in these studies to reveal mechanisms underlying impaired task performance8
and abnormal brain functioning9
, particularly during the processing of social information1,10-11
. While older children and adults with ASD comprise the preponderance of research in this area, eye-tracking may be especially useful for studying young children with the disorder as it offers a non-invasive tool for assessing and quantifying early-emerging developmental abnormalities2,12-13
. Implementing eye-tracking with young children with ASD, however, is associated with a number of unique challenges, including issues with compliant behavior resulting from specific task demands and disorder-related psychosocial considerations. In this protocol, we detail methodological considerations for optimizing research design, data acquisition and psychometric analysis while eye-tracking young children with ASD. The provided recommendations are also designed to be more broadly applicable for eye-tracking children with other developmental disabilities. By offering guidelines for best practices in these areas based upon lessons derived from our own work, we hope to help other investigators make sound research design and analysis choices while avoiding common pitfalls that can compromise data acquisition while eye-tracking young children with ASD or other developmental difficulties.
Medicine, Issue 61, eye tracking, autism, neurodevelopmental disorders, toddlers, perception, attention, social cognition
The α-test: Rapid Cell-free CD4 Enumeration Using Whole Saliva
Institutions: Weill Cornell Medical College , University of Missouri-Kansas City-School of Dentistry, University of Missouri Kansas City- School of Pharmacy, Bamenda, NWP, Cameroon, Mezam Polyclinic HIV/AIDS Treatment Center, Cameroon, Institute for Human Genetics and Biochemistry.
There is an urgent need for affordable CD4 enumeration to monitor HIV disease. CD4 enumeration is out of reach in resource-limited regions due to the time and temperature restrictions, technical sophistication, and cost of reagents, in particular monoclonal antibodies to measure CD4 on blood cells, the only currently acceptable method. A commonly used cost-saving and time-saving laboratory strategy is to calculate, rather than measure certain blood values. For example, LDL levels are calculated using the measured levels of total cholesterol, HDL, and triglycerides1
. Thus, identification of cell-free correlates that directly regulate the number of CD4+
T cells could provide an accurate method for calculating CD4 counts due to the physiological relevance of the correlates.
The number of stem cells that enter blood and are destined to become circulating CD4+
T cells is determined by the chemokine CXCL12 and its receptor CXCR4 due to their influence on locomotion2
. The process of stem cell locomotion into blood is additionally regulated by cell surface human leukocyte elastase (HLECS
) and the HLECS
-reactive active α1
proteinase inhibitor (α1
. In HIV-1 disease, α1
PI is inactivated due to disease processes 4
. In the early asymptomatic categories of HIV-1 disease, active α1
PI was found to be below normal in 100% of untreated HIV-1 patients (median=12 μM, and to achieve normal levels during the symptomatic categories4, 5
. This pattern has been attributed to immune inactivation, not to insufficient synthesis, proteolytic inactivation, or oxygenation. We observed that in HIV-1 subjects with >220 CD4 cells/μl, CD4 counts were correlated with serum levels of active α1
=0.93, p<0.0001, n=26) and inactive α1
=0.91, p<0.0001, n=26) 5
. Administration of α1
PI to HIV-1 infected and uninfected subjects resulted in dramatic increases in CD4 counts suggesting α1
PI participates in regulating the number of CD4+
T cells in blood 3
With stimulation, whole saliva contains sufficient serous exudate (plasma containing proteinaceous material that passes through blood vessel walls into saliva) to allow measurement of active α1
PI and the correlation of this measurement is evidence that it is an accurate method for calculating CD4 counts. Briefly, sialogogues such as chewing gum or citric acid stimulate the exudation of serum into whole mouth saliva. After stimulating serum exudation, the activity of serum α1
PI in saliva is measured by its capacity to inhibit elastase activity. Porcine pancreatic elastase (PPE) is a readily available inexpensive source of elastase. PPE binds to α1
PI forming a one-to-one complex that prevents PPE from cleaving its specific substrates, one of which is the colorimetric peptide, succinyl-L-Ala-L-Ala-L-Ala-p-nitroanilide (SA3
NA). Incubating saliva with a saturating concentration of PPE for 10 min at room temperature allows the binding of PPE to all the active α1
PI in saliva. The resulting inhibition of PPE by active α1
PI can be measured by adding the PPE substrate SA3
NA. (Figure 1)
. Although CD4 counts are measured in terms of blood volume (CD4 cells/μl), the concentration of α1
PI in saliva is related to the concentration of serum in saliva, not to volume of saliva since volume can vary considerably during the day and person to person6
. However, virtually all the protein in saliva is due to serum content, and the protein content of saliva is measurable7
. Thus, active α1
PI in saliva is calculated as a ratio to saliva protein content and is termed the α1
PI Index. Results presented herein demonstrate that the α1
PI Index provides an accurate and precise physiologic method for calculating CD4 counts.
Medicine, Issue 63, CD4 count, saliva, antitrypsin, hematopoiesis, T cells, HIV/AIDS, clinical
Comprehensive & Cost Effective Laboratory Monitoring of HIV/AIDS: an African Role Model
Institutions: National Health Laboratory Services (NHLS-SA), University of Witwatersrand, Lightcurve Films.
We present the video about assisting anti-retroviral therapy (ART) by an apt laboratory service - representing a South-African role model for economical large scale diagnostic testing. In the low-income countries inexpensive ART has transformed the prospects for the survival of HIV seropositive patients but there are doubts whether there is a need for the laboratory monitoring of ART and at what costs - in situations when the overall quality of pathology services can still be very low. The appropriate answer is to establish economically sound services with better coordination and stricter internal quality assessment than seen in western countries. This video, photographed at location in the National Health Laboratory Services (NHLS-SA) at the Witwatersrand University, Johannesburg, South Africa, provides such a coordinated scheme expanding the original 2-color CD4-CD45 PanLeucoGating strategy (PLG). Thus the six modules of the video presentation reveal the simplicity of a 4-color flow cytometric assay to combine haematological, immunological and virology-related tests in a single tube. These video modules are: (i) the set-up of instruments; (ii) sample preparations; (iii) testing absolute counts and monitoring quality for each sample by bead-count-rate; (iv) the heamatological CD45 test for white cell counts and differentials; (v) the CD4 counts, and (vi) the activation of CD8+ T cells measured by CD38 display, a viral load related parameter. The potential cost-savings are remarkable. This arrangement is a prime example for the feasibility of performing > 800-1000 tests per day with a stricter quality control than that applied in western laboratories, and also with a transfer of technology to other laboratories within a NHLS-SA network. Expert advisors, laboratory managers and policy makers who carry the duty of making decisions about introducing modern medical technology are frequently not in a position to see the latest technical details as carried out in the large regional laboratories with huge burdens of workload. Hence this video shows details of these new developments.
Immunology, Issue 44, Human Immunodeficiency virus (HIV); CD4 lymphocyte count, white cell count, CD45, panleucogating, lymphocyte activation, CD38, HIV viral load, antiretroviral therapy (ART), internal quality control
Making MR Imaging Child's Play - Pediatric Neuroimaging Protocol, Guidelines and Procedure
Institutions: Children’s Hospital Boston, University of Zurich, Harvard, Harvard Medical School.
Within the last decade there has been an increase in the use of structural and functional magnetic resonance imaging (fMRI) to investigate the neural basis of human perception, cognition and behavior 1, 2
. Moreover, this non-invasive imaging method has grown into a tool for clinicians and researchers to explore typical and atypical brain development. Although advances in neuroimaging tools and techniques are apparent, (f)MRI in young pediatric populations remains relatively infrequent 2
. Practical as well as technical challenges when imaging children present clinicians and research teams with a unique set of problems 3, 2
. To name just a few, the child participants are challenged by a need for motivation, alertness and cooperation. Anxiety may be an additional factor to be addressed. Researchers or clinicians need to consider time constraints, movement restriction, scanner background noise and unfamiliarity with the MR scanner environment2,4-10
. A progressive use of functional and structural neuroimaging in younger age groups, however, could further add to our understanding of brain development. As an example, several research groups are currently working towards early detection of developmental disorders, potentially even before children present associated behavioral characteristics e.g.11
. Various strategies and techniques have been reported as a means to ensure comfort and cooperation of young children during neuroimaging sessions. Play therapy 12
, behavioral approaches 13, 14,15, 16-18
and simulation 19
, the use of mock scanner areas 20,21
, basic relaxation 22
and a combination of these techniques 23
have all been shown to improve the participant's compliance and thus MRI data quality. Even more importantly, these strategies have proven to increase the comfort of families and children involved 12
. One of the main advances of such techniques for the clinical practice is the possibility of avoiding sedation or general anesthesia (GA) as a way to manage children's compliance during MR imaging sessions 19,20
. In the current video report, we present a pediatric neuroimaging protocol with guidelines and procedures that have proven to be successful to date in young children.
Neuroscience, Issue 29, fMRI, imaging, development, children, pediatric neuroimaging, cognitive development, magnetic resonance imaging, pediatric imaging protocol, patient preparation, mock scanner