Case 1: Assessment: chronic wet cough.
Explore the source record for details and available documents.
Child, Preschool↗
Biomedical subjects
C O'Callaghan
Publications and source records attributed to C O'Callaghan.
Relative roles of pneumolysin and hydrogen peroxide from Streptococcus pneumoniae in inhibition of ependymal ciliary beat frequency.
Ciliated ependymal cells line the ventricular system of the brain and the cerebral aqueducts. This study characterizes the relative roles of pneumolysin and hydrogen peroxide (H(2)O(2)) in pneumococcal meningitis, using the in vitro ependymal ciliary beat frequency (CBF) as an indicator of toxicity. We have developed an ex vivo model to examine the ependymal surface of the brain slices cut from the fourth ventricle. The ependymal cells had cilia beating at a frequency of between 38 and 44Hz. D39 (wild-type) and PLN-A (pneumolysin-negative) pneumococci at 10(8) CFU/ml both caused ciliary slowing. Catalase protected against PLN-A-induced ciliary slowing but afforded little protection from D39. Lysed PLN-A did not reduce CBF, whereas lysed D39 caused rapid ciliary stasis. There was no effect of catalase, penicillin, or catalase plus penicillin on the CBF. H(2)O(2) at a concentration as low as 100 microM caused ciliary stasis, and this effect was abolished by coincubation with catalase. An additive inhibition of CBF was demonstrated using a combination of both toxins. A significant inhibition of CBF at between 30 and 120 min was demonstrated with both toxins compared with either H(2)O(2) (10 microM) or pneumolysin (1 HU/ml) alone. D39 released equivalent levels of H(2)O(2) to those released by PLN-A, and these concentrations were sufficient to cause ciliary stasis. The brain slices did not produce H(2)O(2), and in the presence of 10(8) CFU of D39 or PLN-A per ml there was no detectable bacterially induced increase of H(2)O(2) release from the brain slice. Coincubation with catalase converted the H(2)O(2) produced by the pneumococci to H(2)O. Penicillin-induced lysis of bacteria dramatically reduced H(2)O(2) production. The hemolytic activity released from D39 was sufficient to cause rapid ciliary stasis, and there was no detectable release of hemolytic activity from the pneumolysin-negative PLN-A. These data demonstrate that D39 bacteria released pneumolysin, which caused rapid ciliary stasis. D39 also released H(2)O(2), which contributed to the toxicity, but this was masked by the more severe effects of pneumolysin. H(2)O(2) released from intact PLN-A was sufficient to cause rapid ciliary stasis, and catalase protected against H(2)O(2)-induced cell toxicity, indicating a role for H(2)O(2) in the response. There is also a slight additive effect of pneumolysin and H(2)O(2) on ependymal toxicity; however, the precise mechanism of action and the role of these toxins in pathogenesis remain unclear.
Animals↗
Functional heterogeneity and high frequencies of cytomegalovirus-specific CD8(+) T lymphocytes in healthy seropositive donors.
Human cytomegalovirus (HCMV) infection is largely asymptomatic in the immunocompetent host, but remains a major cause of morbidity in immunosuppressed individuals. Using the recently described technique of staining antigen-specific CD8(+) T cells with peptide-HLA tetrameric complexes, we have demonstrated high levels of antigen-specific cells specific for HCMV peptides and show that this may exceed 4% of CD8(+) T cells in immunocompetent donors. Moreover, by staining with tetramers in combination with antibodies to cell surface markers and intracellular cytokines, we demonstrate functional heterogeneity of HCMV-specific populations. A substantial proportion of these are effector cytotoxic T lymphocytes, as demonstrated by their ability to lyse peptide-pulsed targets in "fresh" killing assays. These data suggest that the immune response to HCMV is periodically boosted by a low level of HCMV replication and that sustained immunological surveillance contributes to the maintenance of host-pathogen homeostasis. These observations should improve our understanding of the immunobiology of persistent viral infection.
CD8-Positive T-Lymphocytes↗
How to choose delivery devices for asthma.
Explore the source record for details and available documents.
Administration, Inhalation↗
Analysis of ciliary beat pattern and beat frequency using digital high speed imaging: comparison with the photomultiplier and photodiode methods.
BACKGROUND: The aim of this study was to determine the relationship of the power and recovery stroke of respiratory cilia using digital high speed video imaging. Beat frequency measurements made using digital high speed video were also compared with those obtained using the photomultiplier and modified photodiode techniques. METHOD: Ciliated epithelium was obtained by brushing the inferior nasal turbinate of 20 healthy subjects. Ciliated edges were observed by microscopy and the deviation of cilia during their recovery stroke relative to the path travelled during their power stroke was measured. Beat frequency measurements made by digital high speed video analysis were compared with those obtained using the photomultiplier and modified photodiode. RESULTS: Cilia were found to beat with a forward power stroke and a backward recovery stroke within the same plane. The mean angular deviation of the cilia during the recovery stroke from the plane of the forward power stroke was only 3.6 degrees (95% CI 3.1 to 4.1). There was a significant difference in beat frequency measurement between the digital high speed video (13.2 Hz (95% CI 11.8 to 14.6)) and both photomultiplier (12.0 Hz (95% CI 10.8 to 13.1), p = 0.01) and photodiode (11.2 Hz (95% CI 9.9 to 12.5), p<0.001) techniques. The Bland-Altman limits of agreement for the digital high speed video were -2.75 to 5.15 Hz with the photomultiplier and -2.30 to 6.06 Hz with the photodiode. CONCLUSION: Respiratory cilia beat forwards and backwards within the same plane without a classical sideways recovery sweep. Digital high speed video imaging allows both ciliary beat frequency and beat pattern to be evaluated.
Adolescent↗
Effect of pneumolysin on rat brain ciliary function: comparison of brain slices with cultured ependymal cells.
This study compares two models for examining ependymal ciliary function: rat brain slices cut from the fourth ventricle and primary ependymal cells in culture. The cilia from both preparations were very reproducible; each preparation had cilia beating at a constant frequency of between 38 and 44 Hz. With the brain slices, ciliary stasis occurred after 5 d in culture. However, ependymal cells had fully functional cilia for up to 48 d in culture. The pneumococcal toxin, pneumolysin, caused a dose-dependent inhibition of cilia beat frequency within 15 min in both models. There were no significant differences in the mean log 50% inhibitory concentration (pIC50) slice = 0.65 +/- 0.05, equivalent to 4.4 hemolytic units (HU)/mL; cells = 0.57 +/- 0.14, equivalent to 3.7 HU/mL. There were also no significant differences in the mean Hill slope factors for the curves (slice = 1.4 +/- 0.05; cells = 1.6 +/- 0.4). These data demonstrate that both models can be used to examine the acute (15-min) effects of pneumolysin on cilia beat frequency. The main advantage of the primary ependymal culture model is that considerably more cultured ependymal cells (approximately 70%) are available, compared with the number of ependymal cells on the brain slices (approximately 2%), thus reducing the number of animals used. A pure ependymal culture was not achieved (approximately 30% of the cells were not ciliated). The increased survival time of the ependymal cells compared with the brain slices make cultured ependymal cells more useful for examining long-term ciliary function, whereas brain slices may be more useful for examining the interactions between ependymal and other nearby cells.
Animals↗
Delivering inhaled corticosteroids to patients.
Explore the source record for details and available documents.
Administration, Inhalation↗
The effect of the pneumococcal toxin, pneumolysin on brain ependymal cilia.
Densely ciliated ependymal cells cover the ventricular surface of the brain and cerebral aqueducts separating cerebrospinal fluid, which is infected in meningitis, from neuronal tissue. We have established an ex vivo model that allows measurement of ependymal ciliary beat frequency, using high-speed video analysis, during incubation with bacterial toxins. Ciliated ependyma, from Wistar rats, was exposed to the pneumococcal toxin, pneumolysin, and a mutant form with markedly reduced cytotoxic activity (;0.1%). Wild-type pneumolysin (1500 HU/ml and 150 HU/ml: 10 and 1 microg/ml) caused rapid ciliary stasis (30-150 s), sloughing of cilia and cytoplasmic extrusion. Ciliary slowing before stasis was seen at 15 HU/ml (0.1 microg/ml); however, no effect on ciliary beat frequency was seen at lower concentrations (1.5 HU/ml and 0.15 HU/ml: 0.01 and 0.001 microg/ml). Mutant pneumolysin, 99.9% deficient in haemolytic activity, caused rapid ciliary stasis at 10 microg/ml but no effect was seen at lower concentrations (1-0.1 microg/ml). Pneumolysin, at levels which may be produced during severe pneumococcal meningitis, may cause rapid ependymal ciliary stasis.
Animals↗
An in vitro analysis of the output of budesonide from different nebulizers.
BACKGROUND: Inhaled corticosteroids are increasingly used in the treatment of asthma, and many different nebulizers are available to aerosolize steroid medications. There are few comparative data on their ability to do so. OBJECTIVE: Our purpose was to determine the particle size and mass output of budesonide nebulizer suspension from different nebulizers. METHODS: In vitro measurement of drug particle size and total drug output from 3 nebulizers (the Pari LC Plus, the Pari LC Star, and the Medicaid Ventstream) was performed under simulated breathing conditions. Nebulizers were charged with 2 mL (500 microg) of budesonide suspension. A sinus pump was used to draw aerosol from the nebulizers onto a filter during simulated inspiration at tidal volumes of 150 and 600 mL, mimicking pediatric and adult use. Aerosol particle size was determined separately by inertial impaction. RESULTS: The LC Plus nebulizer had the highest initial output rate and delivered the most budesonide at both breathing patterns. The maximal output rates of the Ventstream and LC Star nebulizers was half that of the LC Plus, but the LC Star nebulizer continued nebulization for longer and delivered twice as much budesonide as the Ventstream did. However, the Ventstream produced the smallest particles, mass median diameter 3.1 microm compared with 3.8 microm for the LC Star and 4.1 microm for the LC Plus. CONCLUSIONS: This study has identified differences among the nebulizers that would not have been apparent with current standards for nebulizer assessment. Incorporation of breathing simulation in the study imitates patient use and allows effective nebulization times to be predicted. The results suggest that the nebulizers studied would deliver different masses of budesonide to the lungs and to the upper airway. This may have important consequences in determining the efficacy and side effect profile of budesonide.
Budesonide↗
The output of budesonide from spacer devices assessed under simulated breathing conditions.
BACKGROUND: Spacer devices are increasingly used to aid inhalational therapy, and many different devices are available. Patient and spacer size and spacer static charge may affect drug delivery, but the optimum spacer size and method of reducing static charge is not certain. OBJECTIVE: We sought to determine the output of budesonide from 3 different spacer devices when assessed by using simulated breathing at different tidal volumes and to assess the effect of washing and handling the spacer on drug output. METHODS: Three spacer types were assessed: 2 polycarbonate spacers, the Aerochamber and the Nebuhaler, and the metal Nebuchamber or Non-Electrostatic-Spacer. Breathing was simulated by using a sinus flow pump. Metered-dose inhalers of budesonide 200 microg were actuated into the spacer, which was attached to the breathing simulator for 5 simulated breathing cycles. Budesonide was collected on a filter placed between the spacer and breathing simulator and was assayed by HPLC. Spacers were assessed after they had been washed briefly in water, after they had been washed briefly in cetrimide solution in an attempt to reduce their static charge, and after they had been handled to simulate normal use. In separate experiments budesonide particle size from the spacers was measured by using a multistage liquid impinger. RESULTS: Drug output from the Nebuchamber was greater than that from the other 2 spacers, especially at lower tidal volumes. With 150 mL of tidal volume, the Nebuchamber delivered 36% of the nominal dose to the filter versus 13% from the Nebuhaler and 7% from the Aerochamber. The output from the Aerochamber and Nebuhaler increased linearly with tidal volume, but this was not the case with the Nebuchamber, in which output was constant at tidal volumes of 150 mL and above. Compared with washing in tap water, neither washing the spacers in 0.1% cetrimide solution nor vigorous wiping with a paper towel changed their output. Thirty-eight percent of the drug from the Nebuchamber was contained in particles smaller than 4.7 microm in diameter compared with 47% from the Nebuhaler and 53% from the Aerochamber. CONCLUSIONS: The Nebuchamber increases in vitro budesonide delivery compared with the polycarbonate spacers tested but delivers a greater percentage of the drug in large particles. No increase in delivery with tidal volume was seen with the Nebuchamber, which would deliver a higher dose of drug per kilogram of body weight to smaller patients. Briefly washing the polycarbonate spacers in water or in a weak detergent solution, simulating household washing, did not make them as effective as the metal spacer. Further research is needed to determine a practical washing and handling method to reduce static charge on polycarbonate spacers.
Administration, Inhalation↗
New formulation metered dose inhaler increases breath alcohol levels.
A new, chlorofluorocarbon-free metered dose inhaler containing salbutamol, with small amounts of ethanol as a co-solvent, has recently been released. We evaluated the effect on breath alcohol levels of two inhalations from this metered dose inhaler. In 10 volunteers, breath alcohol levels rose to 17.9 micrograms 100 ml-1 breath after an inhalation with a good technique, and to 35 micrograms 100 ml-1 breath (the current legal limit for driving in the UK) after a poor inhalation. Breath alcohol levels were reduced by the use of a spacer device, and in all cases fell to near zero after 2 min. In patients who have just used this type of metered dose inhaler, breath alcohol measurements should be defferred for at least 2 min.
Adult↗
An in vitro analysis of the output of salbutamol from different nebulizers.
The objective of this study was to determine the particle size and mass output of salbutamol from different nebulizers used under simulated breathing conditions. Seven nebulizer/compressor combinations were assessed. Each nebulizer was charged with 5 mg salbutamol solution and connected to a breathing simulator operating at tidal volumes of 150 mL and 600 mL. Nebulizers were operated for 15 min. Salbutamol collected on the filters was measured by liquid chromatography. Aerosol particle size was determined separately by laser diffraction. The Pari LC Star nebulizer delivered the most salbutamol at both tidal volumes. The maximal output of the Medicaid Ventstream and Sidestream nebulizers was two-thirds that of the LC Star, and they delivered less salbutamol than the LC Star or LC Plus nebulizers. The Intersurgical Cirrus nebulizer delivered the least salbutamol at both tidal volumes, although there was only a small difference between the Cirrus and Ventstream or Sidestream nebulizers at 150 mL tidal volume. The LC Plus nebulizer produced larger particles, mass median diameter 5.3 microm, compared with 3.6-4.0 microm for the other nebulizers. In conclusion, there were large differences in the delivery of salbutamol between the nebulizers studied, even between nebulizers of apparently the same class, and this should be borne in mind by regulatory authorities, clinicians and researchers.
Administration, Inhalation↗
Changes in frequency of HIV-1-specific cytotoxic T cell precursors and circulating effectors after combination antiretroviral therapy in children.
Combination antiretroviral therapy has had a major role in reducing human immunodeficiency virus type 1 (HIV-1) plasma viral loads in HIV-1-infected adults but a variable effect in infants, in whom complete viral suppression appears to be less readily achieved. In adults, after the reduction in plasma viremia, there is a decrease in the numbers of circulating cytotoxic T cell (CTL) effectors and precursors in the majority of patients. This longitudinal study assessed the effect of combination drug therapy on the frequency of HIV-1-specific CTL responses in 8 HIV-1-infected children. Following treatment, the frequency of HIV-1-specific CTL responses initially increased, especially in children with incomplete viral suppression but with increasing CD4+ cell counts. In children with complete viral suppression, the frequency of HIV-1-specific CTL responses decreased, suggesting that viral replication is required to maintain CTL responses in the systemic circulation.
Anti-HIV Agents↗
Use of computerized neuropsychological tests (CANTAB) to assess cognitive effects of antihypertensive drugs in the elderly. Cambridge Neuropsychological Test Automated Battery.
OBJECTIVE: To establish reliability and ease of use of the Cambridge Neuropsychological Test Automated Battery (CANTAB) in assessing changes in cognitive function induced by antihypertensive drugs. DESIGN AND METHODS: Standard neuropsychological testing was combined with CANTAB in a double-blind 18-week cross-over study in elderly hypertensives taking perindopril or hydrochlorothiazide/triamterene (HT). Cognitive effects were assessed by employing tests of attention, visuospatial and verbal memory, learning, reasoning, planning, problem solving, speed and coordination. Affect was assessed using two different depression-rating scales. RESULTS: Perindopril and the diuretic had no adverse effects on the various aspects of cognitive function. Mood, as assessed by the Hamilton Depression Rating Scale and the Beck Depression Inventory, was improved on Perindopril, and the error rate in the motor screening test was lower. Ambulatory blood pressure monitoring showed both drugs achieved effective 24-h control. CONCLUSIONS: The ease of use and the ability to adjust the level of testing to the requirements of individual patients, together with the reliability of longitudinal test/re-test results, indicates that CANTAB is an important addition to the methods available to quantitate adverse central nervous system drug effects. The other purpose of the study was to assess any adverse cognitive effects of perindopril against a drug HT believed to have no adverse central nervous system effects. In this context, perindopril was free of adverse effects in all the objective tests employed. In addition, there was a benefit seen in two independent assessments of depression (the Hamilton and the Beck rating scales).
Aged↗
Respiratory and brain ependymal ciliary function.
The aims of this study were to compare beat frequencies of tracheal and ependymal cilia and the beat frequencies of ependymal cilia from infant and adult rats. The length of respiratory and ependymal cilia of infant and adult rats was also compared. We have developed an ex vivo model that allows ependymal and respiratory ciliary beat frequency to be measured with a high-speed video system. The beat frequencies of cilia, incubated at 37 degrees C, were measured after an incubation period of 30 min. Ependymal cilia beat at a similar frequency in 10- to 15-d-old rats (mean 38.8 Hz: 95% confidence intervals 37.1-40.6) as in adult animals (mean 40.7 Hz: 95% confidence intervals 38.5-42.9). However, respiratory cilia from adult animals beat (mean 20.9 Hz: 95% confidence intervals 14-27) at a significantly (p = 0.003) lower frequency than ependymal cilia. Ependymal cilia (mean length +/- SD: 8.2 +/- 0.3 microm) measured by scanning electron microscopy were significantly (p = 0.001) longer than respiratory cilia (5.5 +/- 0.6 microm) from the trachea of 9- to 15-d-old rats. Cilia did not grow longer between the time the rats were 9-15 d old and adulthood. Adult respiratory and ependymal ciliary length (mean +/- SD) were 5.6 +/- 0.5 microm and 8.1 +/- 0.2 microm, respectively. In summary, ependymal cilia beat at approximately twice the rate of respiratory cilia and are significantly longer.
Aging↗
The output of budesonide from nebulizers.
Explore the source record for details and available documents.
Administration, Inhalation↗
Drug output from nebulizers is dependent on the method of measurement.
The objective of this study was to determine whether current regulatory methods for assessing the output of nebulizers are appropriate for the delivery of nebulized steroid suspensions to patients. We studied a conventional jet nebulizer (the Intersurgical Cirrus), an open-vent nebulizer (the Medicaid Sidestream) and a breath-enhanced nebulizer (the Pari LC Plus), using a constant sampling flow or a sinusoidal pump to represent the breathing pattern of children from 6 months to adulthood. Recovery of budesonide released from the nebulizers onto filters was reduced when using breathing simulation compared with constant flow, and this reduction was greatest for the conventional nebulizer (Cirrus, 103 microg with constant flow to 4.4 microg with a 50 mL tidal volume; Pari, 176 microg to 25 microg). The open-vent nebulizer deposited very little budesonide on the filter at lower tidal volumes (4.5 microg with a 50 mL tidal volume), possibly because the enhanced flow of aerosol laden air was greater than the inspiratory flow from the breathing simulator. The output of the LC plus was reduced at high flow, from 176 microg at 20 L x min(-1) to 93 microg at 60 L x min(-1). Overall, the measured output varied by up to 700%, depending on the method used. These results suggest that breathing patterns dramatically alter the measured output of different nebulizers and that breathing simulation should be included as part of their assessment.
Adolescent↗
Primary ciliary dyskinesia: diagnosis and standards of care.
Primary ciliary dyskinesia (PCD) is characterized by disease of the upper and lower respiratory tract, in association with visceral mirror image arrangement in 50% of cases, due to abnormal structure and/or function of cilia. The purpose of this paper is to review the clinical features, diagnosis and management of PCD. Presentations include neonatal respiratory distress, recurrent lower respiratory tract infection, chronic rhinosinusitis and male infertility. PCD enters the differential diagnosis of bronchiectasis, atypical asthma, and unusually severe upper airway disease. Diagnosis is by a cascade of investigations, starting with the saccharin test in patients older than 10 yrs; ciliary beat frequency and pattern on light microscopy; and electron microscopy to assess ciliary morphology and orientation. It is important not to confuse primary and secondary ciliary abnormalities. Nasal nitric oxide is low in PCD, and this measurement shows promise as a screening test for PCD. Diagnosis is important, in order to prevent the development of bronchiectasis and to avoid any unnecessary otorhinolaryngological procedures. Regular follow-up is essential, and management should be multidisciplinary, with input from centres with a special interest in PCD, having access to paediatric and adult chest physicians, otolaryngologists and audiological physicians, physiotherapists, counselling services and fertility clinics. The prognosis is good, but morbidity can be considerable if PCD is incorrectly managed.
Adult↗