Dynamic acoustic field activated cell separation (DAFACS)

Advances in diagnostics, cell and stem cell technologies drive the development of application-specific tools for cell and particle separation. Acoustic micro-particle separation offers a promising avenue for high-throughput, label-free, high recovery, cell and particle separation and isolation in regenerative medicine. Here, we demonstrate a novel approach utilizing a dynamic acoustic field that is capable of separating an arbitrary size range of cells. We first demonstrate the method for the separation of particles with different diameters between 6 and 45 μm and secondly particles of different densities in a heterogeneous medium. The dynamic acoustic field is then used to separate dorsal root ganglion cells. The shearless, label-free and low damage characteristics make this method of manipulation particularly suited for biological applications. Advantages of using a dynamic acoustic field for the separation of cells include its inherent safety and biocompatibility, the possibility to operate over large distances (centimetres), high purity (ratio of particle population, up to 100%), and high efficiency (ratio of separated particles over total number of particles to separate, up to 100%).

Memory for single items, word pairs, and temporal order of different kinds in a patient with selective hippocampal lesions

One kind of between-list and two kinds of within-list temporal order memory were examined in a patient with selective bilateral hippocampal lesions. This damage disrupted memory for all three kinds of temporal order memory, but left item and word pair recognition relatively intact. These findings are inconsistent with claims that (1) hippocampal lesions, like those of the medial temporal lobe (MTL) cortex, disrupt item and word pair recognition, and that (2) hippocampal lesions disrupt temporal order memory and item recognition to the same degree. Not only was word pair recognition intact in the patient, but further evidence indicates that her recognition of other associations between items of the same kind is also spared so retrieval of such associations cannot be sufficient to support within-list temporal order recognition. Rather, as other evidence indicates that the patient is impaired at recognition of associations between different kinds of information, within-list (and possibly between-list) temporal order memory may be impaired by hippocampal lesions because it critically depends on retrieving associations between different kinds of information.

Targeting the vaginal mucosa with human papillomavirus pseudovirion vaccines delivering simian immunodeficiency virus DNA

The majority of HIV infections occur via mucosal transmission. Vaccines that induce memory T and B cells in the female genital tract may prevent the establishment and systemic dissemination of HIV. We tested the immunogenicity of a vaccine that uses human papillomavirus (HPV)-based gene transfer vectors, also called pseudovirions (PsVs), to deliver SIV genes to the vaginal epithelium. Our findings demonstrate that this vaccine platform induces gene expression in the genital tract in both cynomolgus and rhesus macaques. Intravaginal vaccination with HPV16, HPV45, and HPV58 PsVs delivering SIV Gag DNA induced Gag-specific Abs in serum and the vaginal tract, and T cell responses in blood, vaginal mucosa, and draining lymph nodes that rapidly expanded following intravaginal exposure to SIV(mac251.) HPV PsV-based vehicles are immunogenic, which warrant further testing as vaccine candidates for HIV and may provide a useful model to evaluate the benefits and risks of inducing high levels of SIV-specific immune responses at mucosal sites prior to SIV infection.

Improvement in duration of erection following phosphodiesterase type 5 inhibitor therapy with vardenafil in men with erectile dysfunction: the ENDURANCE study

OBJECTIVE

The ENDURANCE study evaluated the efficacy of vardenafil, a phosphodiesterase type 5 (PDE5) inhibitor, in men with erectile dysfunction (ED), by measuring the duration of erection leading to successful intercourse using a stopwatch as the assessment instrument.

METHODS

This was a randomised, multicentre, double-blind, placebo-controlled, crossover study consisting of a 4-week treatment-free run-in phase after which patients were randomised to either fixed-dose vardenafil 10 mg or placebo (to be administered 60 min prior to intercourse) and entered the first of the two 4-week double-blind treatment periods, separated by a 1-week washout. The primary efficacy end-point was the stopwatch-assessed duration of erection, which was defined as the time from erection perceived hard enough for penetration until withdrawal from the partner's vagina leading to successful intercourse as measured by Sexual Encounter Profile Question 3 (SEP-3). Secondary efficacy end-points included SEP-2 and SEP-3 success rates, the erectile function domain of the International Index of Erectile Function, global assessment questionnaire, change from baseline in duration of erection and duration of erection not leading to successful intercourse. Safety was assessed by adverse events (AEs), laboratory samples, vital signs and ECGs.

RESULTS

Of the 191 men included in the safety population, 40% had moderate ED and 33% had severe ED at baseline. The duration of erection (least squares mean +/- SE) leading to successful intercourse was longer with vardenafil than with placebo (12.81 +/- 1.00 min vs. 5.45 +/- 1.00 min; p < 0.001). The differences recorded for all secondary end-points were statistically significant in favour of vardenafil compared with placebo (p < 0.001), with the exception of duration of erection not leading to successful intercourse. Vardenafil was well tolerated in this study; the majority of AEs being mild-to-moderate in intensity.

CONCLUSION

Vardenafil 10-mg therapy provided a statistically superior duration of erection leading to successful intercourse in men with ED compared with placebo.

Can the standard gamble and rating scale be used to measure quality of life in rhinoconjunctivitis? Comparison with the RQLQ and SF-36

BACKGROUND

With interest in health economics growing, it is important to know whether utilities may be used to measure health-related quality of life in patients with rhinoconjunctivitis. The objective was to compare the validity and measurement properties of disease-specific versions of the standard gamble and rating scale with those of the Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ) and the Short-Form 36 (SF-36).

METHODS

One hundred adults with symptomatic rhinoconjunctivitis participated in a 5 week observational study, completing the standard gamble, rating scale, RQLQ and SF-36 at baseline and after 1 and 5 weeks. Symptom diaries were completed for 1 week before each follow-up visit.

RESULTS

Reliability was highest for the RQLQ (intraclass correlation coefficient = 0.97), followed by the rating scale (0.75), the SF-36 physical (0.75), the SF-36 mental (0.74) and the standard gamble (0.12). The responsiveness index was highest for the RQLQ (0.76), followed by the rating scale (0.56) and the SF-36 mental (0.28). Both cross-sectional and longitudinal validity were strongest for the RQLQ and the rating scale.

CONCLUSIONS

Both the rating scale and the RQLQ have strong evaluative and discriminative properties. The SF-36 has acceptable discriminative properties but its evaluative properties are poor. All measurement properties for the standard gamble are inadequate. Poor correlation between the standard gamble and the rating scale indicates that utilities cannot be derived from rating scale data.

Remembering and knowing in a patient with preserved recognition and impaired recall

ROB is a patient who has a severe deficit in recalling recently presented verbal material following rupture and repair of an anterior communicating artery aneurysm [Hanley JR, Davies ADM, Downes J, Mayes A. Cognitive Neuropsychology 1994;11:543-78; Hanley JR, Davies ADM. In: Parkin A, editor. Case Studies in the Neuropsychology of Memory. Hillsdale, NJ: Lawrence Erlbaum, 1997. p. 111-26]. Despite this, her performance on tests of recognition memory is comfortably within the normal range. In the present series of experiments, we investigated whether or not ROB's performance on tests of recognition memory might be associated with a disproportionately large number of correct decisions made on the basis of familiarity rather than contextual retrieval [e.g. Mandler G. Psychological Review 1980;87:252-71]. Contrary to this hypothesis, the results showed that ROB made a high proportion of remember decisions relative to know decisions in recognition [cf. Gardiner JM. Memory & Cognition 1988;16:309-13] and produced a high recollection score when conscious recollection and familiarity were placed in opposition to one another [cf. Jacoby LL, Woloshyn V, Kelley C. Journal of Experimental Psychology: General 1989;118:115-25.]. ROB's recognition memory performance therefore appears to be qualitatively as well as quantitatively similar to that found in the normal population. As ROB has suffered damage to both the fornix and the anterior thalamus, the results of the present study are consistent with the claim that damage to the extended hippocampal system has a much more severe effect on recall than on recognition [Aggleton JP, Shaw C. Neuropsychologia 1996;34:51-62; Aggleton JP, Saunders RC. Memory 1997;5:49-71]. The present results provide no support, however, for the additional suggestion [Aggleton JP, Brown MW. Behavioral and Brain Sciences 1999;22:425-56.] that the extended hippocampal system is necessary for recognition memory decisions that are based on contextual retrieval.

Comparison of the standard gamble, rating scale, AQLQ and SF-36 for measuring quality of life in asthma

With interest in health economics growing, there is a demand for valid methods for measuring health-related quality of life (HRQL) in asthma using utilities. The aims of this study were to develop disease-specific versions of the standard gamble and rating scale, to compare their measurement properties with those of the Asthma Quality of Life Questionnaire (AQLQ) and the Medical Outcomes Survey Short-Form 36 (SF-36), as well as to determine their validity for assessing asthma-specific quality of life. Forty adults with symptomatic asthma participated in a 9-week observational study. Participants completed the standard gamble, rating scale, AQLQ, SF-36 and other measures of clinical asthma status at baseline and after 1, 5 and 9 weeks. In patients whose asthma was stable between assessments, reliability was good for the rating scale (intraclass correlation coefficient (ICC)=0.89) and the AQLQ (ICC=0.95) but more modest for the SF-36 mental score (ICC=0.68), SF-36 physical score (ICC=0.65) and standard gamble (ICC=0.59). The responsiveness index was highest in the AQLQ (1.35), followed by the rating scale (0.74), the physical score of the SF-36 (0.61) and the standard gamble (0.31). Construct validity (correlation with other indices of health status) was strongest for the AQLQ and the rating scale. In conclusion, both the disease-specific rating scale and the Asthma Quality of Life Questionnaire have strong measurement properties for measuring asthma-specific quality of life; the Short-Form 36 health survey physical summary score has more modest properties. Although the disease-specific standard gamble has acceptable discriminative properties, its evaluative properties are too inadequate for it to be used in cost/utility analyses. Poor correlation between the standard gamble and the rating scale indicates that utilities cannot be derived from rating scale data.

Measuring asthma control in group studies: do we need airway calibre and rescue beta2-agonist use?

Collection of airway calibre and beta2-agonist data in large clinical trials and epidemiological surveys is sometimes difficult and may be an inefficient use of resources. The aim of this study was to determine whether the omission of the forced expiratory volume in 1 sec (FEV1) and beta2-agonist questions from the seven-item Asthma Control Questionnaire (ACQ) alters its measurement properties and validity. In an observational study, 50 adults with symptomatic asthma attended the clinic at 0, 1, 5 and 9 weeks to complete the ACQ and other measures of asthma status. All patients completed the study and provided complete data sets. Omission of the FEV1 and beta2-agonist questions from the ACQ made minimal difference to the reliability, responsiveness, and both cross-sectional and longitudinal validity of the instrument. Omission of the FEV1 question significantly lowered the summary score (P<0.001) but omission of the beta2-agonist question did not alter it (P>0.05). In group studies, both the FEV1 and beta2-agonist questions may be omitted from the ACQ without changing the validity or the measurement properties of the instrument. Lowering of the summary score by the omission of the FEV1 question means that data from this abbreviated form cannot be combined with or compared to data collected using the full questionnaire.

Measuring asthma control. Clinic questionnaire or daily diary?

Daily symptom, peak expiratory flow rate (PEFR), and medication diaries are often used in clinical trials of treatments for asthma on the assumption that they provide a better estimate of clinical status than does a questionnaire completed in the clinic. We conducted a study with the aim of comparing the measurement properties of the clinic-completed Asthma Control Questionnaire with those of the Asthma Control Diary. The diary is composed of questions and response options almost identical to those of the questionnaire, but uses PEFR instead of FEV(1) as the measure of airway caliber. In an observational study, 50 adults with symptomatic asthma attended a McMaster University asthma clinic at 0, 1, 5, and 9 wk to complete the Asthma Control Questionnaire and other measures of asthma status. For 1 wk before each follow-up visit, patients completed the Asthma Control Diary every morning and evening. Concordance between the questionnaire and diary was high (intraclass correlation coefficient [ICC] = 0.87). Both reliability (ICC: questionnaire = 0.90; diary = 0.86) and responsiveness (responsiveness index: questionnaire = 1.06; diary = 0.90; p = 0.005) were better with the questionnaire than with the diary. Correlations between the two instruments and other measures of clinical asthma status were similar and close to a priori predictions. Both the Asthma Control Questionnaire and the Asthma Control Diary are valid instruments for measuring asthma control, but the questionnaire has slightly better discriminative and evaluative measurement properties than does the diary.

Development and validation of the mini Rhinoconjunctivitis Quality of Life Questionnaire

BACKGROUND

The 28-item Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ) has strong measurement properties but for large clinical trials, surveys and practice monitoring, where high efficiency is important, a shorter questionnaire is needed.

OBJECTIVE

To develop and validate an abbreviated version of the RQLQ.

METHODS

Using five RQLQ databases, items with high item-item correlations were combined and then the highest scoring items were selected for the MiniRQLQ (14 questions). There are five domains: activity limitations (standardized), practical problems and nose symptoms, eye symptoms and other symptoms. The MiniRQLQ, which is self-administered, was tested in a 5-week observational study in 100 adults with symptomatic rhinoconjunctivitis. Patients completed the MiniRQLQ, the RQLQ, and other measures of health status at baseline, 1 and 5 weeks.

RESULTS

In patients whose rhinoconjunctivitis was stable between clinic visits, reliability (reproducibility and ability to discriminate between patients of different impairment) was very acceptable for the MiniRQLQ (ICC = 0.93) but not quite as good as for the RQLQ (ICC = 0.97). Responsiveness to change in clinical status was better with the MiniRQLQ than the RQLQ (P = 0. 044). Construct validity (correlation with other indices of health status) was strong for both the MiniRQLQ and the RQLQ. Concordance between the two instruments was high (ICC = 0.87).

CONCLUSIONS

The MiniRQLQ has strong measurement properties and measures the same construct as the original RQLQ. The choice of questionnaire should depend on the task at hand.

Validation of the standardized version of the Rhinoconjunctivitis Quality of Life Questionnaire

BACKGROUND

In the Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ), the 3 activity questions are selected by the patients themselves. For greater efficiency, a version with standardized activities is required.

OBJECTIVE

Our purpose was to develop and validate a standardized version of the RQLQ, the RQLQ(S).

METHODS

With use of 5 RQLQ databases, we identified the activities most frequently selected by patients and formulated 3 generic questions that would encompass the majority of these activities. The RQLQ(S) was tested in a 5-week observational study in 100 adults with symptomatic rhinoconjunctivitis. Patients completed the RQLQ(S), the RQLQ, and other measures of health status at baseline and 1 and 5 weeks.

RESULTS

The activity domain of the RQLQ(S) consistently gave lower scores than did the activity domain of the RQLQ (P <.001). However, this made very little difference to the overall scores (RQLQ[S] = 2.36 +/- 1.23, RQLQ = 2.43 +/- 1.23), and overall concordance was high (intraclass correlation coefficient = 0.996). In patients whose rhinoconjunctivitis was stable between clinic visits, reliability (reproducibility and ability to discriminate between patients of different impairment) was high for both instruments and almost identical (intraclass correlation coefficient = 0.97). Responsiveness to change was also very similar and good (P <.001). Construct validity (correlation with other index values of health status) was strong for both the RQLQ(S) and the RQLQ.

CONCLUSIONS

The RQLQ(S) has strong measurement properties and measures the same construct as the original RQLQ. The choice of questionnaire should depend on the task at hand.

Absolute metabolite quantification by in vivo NMR spectroscopy: II. A multicentre trial of protocols for in vivo localised proton studies of human brain

We have performed a multicentre trial to assess the performance of three techniques for absolute quantification of cerebral metabolites using in vivo proton nuclear magnetic resonance (NMR). The techniques included were 1) an internal water standard method, 2) an external standard method based on phantom replacement, and 3) a more sophisticated method incorporating elements of both the internal and external standard approaches, together with compartmental analysis of brain water. Only the internal water standard technique could be readily implemented at all participating sites and gave acceptable precision and interlaboratory reproducibility. This method was insensitive to many of the experimental factors affecting the performance of the alternative techniques, including effects related to loading, standing waves and B1 inhomogeneities; and practical issues of phantom positioning, user expertise and examination duration. However, the internal water standard method assumes a value for the concentration of NMR-visible water within the spectroscopic volume of interest. In general, it is necessary to modify this assumed concentration on the basis of the grey matter, white matter and cerebrospinal fluid (CSF) content of the volume, and the NMR-visible water content of the grey and white matter fractions. Combining data from 11 sites, the concentrations of the principal NMR-visible metabolites in the brains of healthy subjects (age range 20-35 years) determined using the internal water standard method were (mean+/-SD): [NAA]=10.0+/-3.4 mM (n=53), [tCho]=1.9+/-1.0 mM (n=51), [Cr + PCr]=6.5+/-3.7 mM (n=51). Evidence of system instability and other sources of error at some participating sites reinforces the need for rigorous quality assurance in quantitative spectroscopy.