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Paul Morrison

Publications and source records attributed to Paul Morrison.

17 recordsLinked to original sources
PubMed2006

Targeted multidimensional gas chromatography for the quantitative analysis of suspected allergens in fragrance products.

Two approaches are described and compared for the analysis of suspected allergens (SAs) in fragrance products, which are defined by the Scientific Committee of Cosmetics and Non-Food Products (SCCNFP). The first consists of a comprehensive two-dimensional gas chromatography (GC x GC) experiment using both a "conventional" non-polar/polar column combination and an "inverse" polar/non-polar column set. The second approach uses a targeted multidimensional gas chromatography (MDGC) system employing a Deans type pneumatic switch and a longitudinally modulated cryogenic system (LMCS). It was found that the conventional and inverse column sets complement each other well, providing identification of SAs present. Compounds well retained on the second dimension of one column set were the first to be eluted from the other. In some instances SAs co-eluting with matrix components on the second dimension for a given column set were clearly resolved on the other, although this has the disadvantage of requiring two analytical runs. Targeted MDGC with a non-polar/polar column set, successfully separated all SAs identified within a fragrance product. The instrument is set up in a similar fashion to a GC x GC system though with longer second dimension ((2)D) column, a cryogenic trap at the beginning of the second column, and a pneumatic switch coupling both columns. The data are easier to process than for a GC x GC experiment. The targeted MDGC method has the capacity to deliver far greater efficiency to targeted regions of a primary separation than a GC x GC experiment, whilst still maintaining overall run times similar to those of a conventional one-dimensional (1D) GC experiment. Cryogenic focussing at the beginning of the (2)D column delivers enhanced sensitivity, accurate (2)D retention times and narrow peak widths; these are responsible for an increased resolution obtained from the fast, relatively short (approximately 5 m) (2)D column. The two column set GC x GC analysis provided a quick and effective means to qualitatively determine the presence of six SAs in a commercially available air freshener, however all were not adequately resolved from matrix components. In contrast, quantitation was straightforward using the targeted MDGC method.

Allergens↗
PubMed2006

Rho is a presynaptic activator of neurotransmitter release at pre-existing synapses in C. elegans.

Rho GTPases have important roles in neuronal development, but their function in adult neurons is less well understood. We demonstrate that presynaptic changes in Rho activity at Caenorhabditis elegans neuromuscular junctions can radically change animal behavior via modulation of two separate pathways. In one, presynaptic Rho increases acetylcholine (ACh) release by stimulating the accumulation of diacylglycerol (DAG) and the DAG-binding protein UNC-13 at sites of neurotransmitter release; this pathway requires binding of Rho to the DAG kinase DGK-1. A second DGK-1-independent mechanism is revealed by the ability of a Rho inhibitor (C3 transferase) to decrease levels of release even in the absence of DGK-1; this pathway is independent of UNC-13 accumulation at release sites. We do not detect any Rho-induced changes in neuronal morphology or synapse number; thus, Rho facilitates synaptic transmission by a novel mechanism. Surprisingly, many commonly available human RhoA constructs contain an uncharacterized mutation that severely reduces binding of RhoA to DAG kinase. Thus, a role for RhoA in controlling DAG levels is likely to have been underestimated.

ADP Ribose Transferases↗
PubMed2005

Orthogonality considerations in comprehensive two-dimensional gas chromatography.

This study explores separation orthogonality with respect to comprehensive two-dimensional gas chromatography (GC x GC) for a range of different column polarities in the first dimension (1D), with two second dimension (2D) column types. Systematic variation in the net polarity of the first dimension allows the effect of column phase relative polarity on analyte retention in both the first and second dimensions to be evaluated. First dimension polarity manipulation significantly affects elution temperature (T(e)) of the analytes. This alters the magnitude of retention on the second dimension, and the extent of utility of separation space. By use of retention factor/temperature data in single column experiments, along with 1D T(e) data, retention on the 2D column can be estimated. This allows the two-dimensional separation to be predicted, and compared with experimental data. Predicted GC x GC peak positions corresponded favourably with the experimentally derived chromatograms, yielding a simple approach for predicting two-dimensional separations, using unique column set combinations.

Chromatography, Gas↗
PubMed2005

Specific in vitro binding of (S,S)-[3H]MeNER to norepinephrine transporters.

The aim of this study was to determine the selectivity of (S,S)-2-(alpha-(2-methoxyphenoxy)benzyl)morpholine (MeNER) binding to norepinephrine transporters (NET). Quantitative autoradiography studies of NET binding were performed in brains of wildtype mice and those of mutant mice lacking one or two alleles of the NET gene. [3H]MeNER binding in the wildtype mouse brains was consistent with previously reported distributions of NET. Highest levels were found in the locus coeruleus, thalamus, hypothalamus, and bed nucleus of stria terminalis. Specific binding in these regions was approximately 50% in the heterozygous NET mice and negligible in the NET knockout mice. Binding in the wildtype mouse brains was displaced by the NET ligand, nisoxetine, but not by the serotonin or dopamine transporter blockers, citalopram or GBR 12935. [3H]MeNER displayed much higher affinity for NET than for SERT or DAT in homogenate binding studies. Each of these features supports the binding specificity of this candidate in vivo NET ligand.

Animals↗
PubMed2005

Local distribution and toxicity of prolonged hippocampal infusion of muscimol.

OBJECT: The activity of gamma-aminobutyric acid (GABA), the principal inhibitory neurotransmitter, is reduced in the hippocampus in patients with complex partial seizures from mesial temporal sclerosis. To provide preliminary safety and distribution data on using convection-enhanced delivery of agents to treat complex partial seizures and to test the efficacy and safety of regional selective neuronal suppression, the authors infused muscimol, a GABA-A receptor agonist, directly into the hippocampus of nonhuman primates using an integrated catheter electrode. METHODS: Ten rhesus monkeys were divided into three groups: 1) use of catheter electrode alone (four monkeys); 2) infusion of escalating concentrations of muscimol followed by vehicle (three monkeys); and 3) infusion of vehicle and subsequent muscimol mixed with muscimol tracer (three monkeys). Infusions were begun 5 days after catheter electrode placement and continued for 5.6 days before switching to the other agent. Head magnetic resonance (MR) images and electroencephalography recordings were obtained before and during the infusions. Brain histological studies and quantitative autoradiography were performed. Neurological function was normal in controls and when muscimol concentrations were 0.125 mM or less, whereas higher concentrations (0.5 and 1 mM) produced reversible apathy and somnolence. Fluid distribution was demonstrated on MR images and muscimol distribution was demonstrated on autoradiographs throughout the hippocampus and adjacent white matter. CONCLUSIONS: Targeted modulation of neuronal activity is a reasonable research strategy for the investigation and treatment of medically intractable epilepsy.

Animals↗
PubMed2004

Rapid sequential heart-cut multidimensional gas chromatographic analysis.

A method is described which allows the sequential fast analysis of heart-cuts taken during the first column elution of an essential oil sample in a multidimensional gas chromatography experiment. In this investigation, a relatively short, narrow bore capillary column is used in the second dimension, with fast cryogenic modulation permitting rapid delivery of cryofocussed heart-cuts into the second column of the multidimensional arrangement. In this implementation, the total analysis time on the second column is of the order of 30 s, which is less than the duration of the sampled heart-cuts (1 min), with peak theoretical efficiencies of about 7000 m(-1). Thus, the method should allow on-line heart-cutting of as many discrete heart-cuts as one may require from the first dimension chromatogram, and so two-dimensional separation can be achieved for almost the whole sample in one single analysis without the need for repeat injections or cycling of the oven temperature. The method is demonstrated by the transfer and rapid re-injection of 1 min heart-cuts taken from an initial separation stage of peppermint essential oil. The cryofocussing and fast analysis step is shown to increase signal response by up to 40-fold. Total peak capacity in the described system is measured to be of the order of 1800, with capacities of about 20-30 for each 30 s second dimension analysis. By increasing the frequency of sampling to remove excessive (unused) time to develop the 2D separation, it should be possible to achieve peak capacities of 5000 or more baseline resolved peaks.

Chromatography, Gas↗
PubMed2004

Effects of pressure drop on absolute retention matching in comprehensive two-dimensional gas chromatography.

Comprehensive two-dimensional gas chromatography (GC x GC) analysis has the capability to resolve many more components of complex mixtures than traditional single column GC analysis. There is an increasing need to provide reliable identification of these separated components; time-of-flight mass spectrometry (TOFMS) is the most appropriate technology to achieve this task. Rather than require MS for all GC x GC separations, it is desirable to assign peak identities to specific peak positions in the GC x GC separation space, and this necessitates matching peak retentions in the two experiments - GC x GC-FID and GC x GC-TOFMS. The atmospheric vs. vacuum outlet conditions confound this task. It is shown here that by employing a supplementary gas supply, provided to a T-union between the column outlet and the MS interface, it is possible to generate 2D chromatograms for GC x GC-FID and GC x GC-TOFMS that are essentially exactly matched. There is no degradation in separation performance or efficiency in the second column in the system interfaced to the T-union. Since the GC x GC-FID experiment uses hydrogen for maximum efficiency, and GC x GC-TOFMS uses helium carrier, translation of (conditions/retentions) must account for the different viscosities of the carrier gases. Translation of conditions is based on well-known principles established in single column analysis. Tabulated data illustrate that retention reproducibility was of the order of better than 4 s for the average first dimension retention difference, and about 40 ms for the average second dimension retention difference when comparing GC x GC-FID and GC x GC-TOFMS results. This should provide considerable support for identification in routine GC x GC-FID analysis of specific sample types, once the peaks in 2D separation space have been assigned identities through GC x GC-TOFMS analysis.

Chromatography, Gas↗
PubMed2004

Comprehensive two-dimensional gas chromatography with flame ionization and time-of-flight mass spectrometry detection: qualitative and quantitative analysis of West Australian sandalwood oil.

The use of gas chromatography (GC)-mass spectrometry (MS), GC-time-of-flight MS (TOFMS), comprehensive two-dimensional GC (GCxGC)-flame ionization detection (FID), and GCxGC-TOFMS is discussed for the characterization of the eight important representative components, including Z-alpha-santalol, epi-alpha-bisabolol, Z-alpha-trans-bergamotol, epi-beta-santalol, Z-beta-santalol, E,E-farnesol, Z-nuciferol, and Z-lanceol, in the oil of west Australian sandalwood (Santalum spicatum). Single-column GC-MS lacks the resolving power to separate all of the listed components as pure peaks and allow precise analytical measurement of individual component abundances. With enhanced peak resolution capabilities in GCxGC, these components are sufficiently well resolved to be quantitated using flame ionization detection, following initial characterization of components by using GCxGC-TOFMS.

Gas Chromatography-Mass Spectrometry↗
PubMed2003

Targeted multidimensional gas chromatography using microswitching and cryogenic modulation.

A new method is described that allows fast target analysis in multidimensional gas chromatography by using a microswitching valve between two GC columns, with cryogenic trapping and rapid re-injection of trapped solutes in the second dimension. The essence of the procedure is that heart-cut fractions from the first column (1D) can be selectively transferred to column 2 (2D), where a moveable cryogenic trap first focuses the transferred solute(s) at the head of the second column and then permits their facile rapid analysis on 2D. Since 2D is a short narrow-bore column, which exhibits very fast analysis (on the order of a few seconds elution), peak responses (heights) are significantly enhanced (by up to 40-fold). Additionally, by using a 2D phase of a selectivity different from that used for 1D, it is possible to also separate components that are not resolved on the first column and to increase the resolution for other compounds. The heart-cut valve isolates the section(s) of solutes of interest from the first column separation, and this provides a considerable simplification to the chromatogram-in addition to the separation and sensitivity advantages. By using this method, multidimensional gas chromatography with multiple heart-cuts can be completed within the same time as the primary column separation. Since the described method permits non-heart-cut fractions to be transferred to a monitor detector, normal detection of these fractions is still permitted. By modulation of the cryotrap, it is also possible to achieve comprehensive two-dimensional gas chromatography for the heart-cut fractions; however, only those compounds passed to the second, separation column, which passes through the cryotrap, will be subjected to GC x GC analysis. The technique and the various modes of operation are described in this paper.

Journal Article↗
PubMed2003

Primary endothelial cells isolated from the yolk sac and para-aortic splanchnopleura support the expansion of adult marrow stem cells in vitro.

The embryonic origin and development of hematopoietic and endothelial cells is highly interdependent. We hypothesized that primary endothelial cells from murine yolk sac and para-aortic splanchnopleura (P-Sp) may possess the capacity to expand hematopoietic stem cells (HSCs) and progenitor cells ex vivo. Using Tie2-GFP transgenic mice in combination with fluorochrome-conjugated monoclonal antibodies to vascular endothelial growth factor receptor-2 (Flk1) and CD41, we have successfully isolated pure populations of primary endothelial cells from 9.5-days after coitus (dpc) yolk sac and P-Sp. Adult murine bone marrow Sca-1+c-Kit+lin- cells were cocultured with yolk sac or P-Sp Tie2-GFP+Flk-1+CD41- endothelial cell monolayers for 7 days and the total number of nonadherent cells increased 47- and 295-fold, respectively, and hematopoietic progenitor counts increased 9.4- and 11.4-fold, respectively. Both the yolk sac and P-Sp endothelial cell cocultures facilitated long-term (> 6 months) HSC competitive repopulating ability (2.8- to 9.8-fold increases, respectively). These data suggest that 9.5-dpc yolk sac- and P-Sp-derived primary Tie2-GFP+Flk-1+CD41- endothelial cells possess the capacity to expand adult bone marrow hematopoietic progenitor cell and HSC repopulating ability ex vivo.

Animals↗
PubMed2003

University and industry partnerships: lessons from collaborative research.

Collaborative research between educational institutions and health agencies is being increasingly used as a method of achieving joint outcomes and bringing together theory and practice. This paper reports on the experiences of collaboration that arose out of just such a project carried out in a residential aged care setting. The research team included university academics, two nurses in management positions in the aged care facility and a senior research assistant. In this paper, we explore some of the unexpected issues that emerged during implementation of the research project. The major challenges to successful collaboration arose not from within the collaborative research team, but from the responses of the broader staff who generally had little, if any, experience of research. Despite efforts to inform and involve staff, deep suspicions about the 'real' motives of the project proved difficult to shift. Trust and commitment are vital dimensions of successful collaborative research, yet gaining these from some staff proved elusive. Collaborative relationships between educational and practice settings need to be viewed as long-term endeavours driven by a common unifying goal to enhance client care. This has implications for costs and timelines which might be difficult to manage.

Activities of Daily Living↗
PubMed2003

Challenges associated with implementing an education program in a residential aged care setting.

The link between independence and well-being of older people in residential care is well established. This paper reports some challenges encountered during implementation of an education program designed to assist nursing staff to adopt an independence-supporting model of residential care. The education program was part of a larger project aimed at developing an example of best practice in supported care which promotes independence, well-being and community linkages. Implementation of the program created many interesting challenges which were overcome by strategies and facilitating forces such as support from management and some staff and the collaborative nature of the project. Positive outcomes of the education program included increased awareness of and change in, practice; increased staff-resident interaction; and increased encouragement for residents to be independent and to engage with the wider community. Moreover, a facilitator manual - Promoting Independence: A Learning Resource for Aged Care Workers was subsequently developed so that the program can be implemented in aged care facilities elsewhere.

Activities of Daily Living↗
PubMed2003

Pluripotent stem cells identified in multiple murine tissues.

Pluripotential stem cells (PSCs) have been recently described in many tissues including skeletal muscle, brain, and bone marrow. However, the true nature of these cells is still unclear, and their precise definition has yet to be determined. We hypothesized that a common, rare population of PSCs with a broad tissue differentiation potential can be identified in multiple murine tissues and that these cells are capable of transdifferentiation into cells of different primordial germ layer origins in response to diverse microenvironmental cues. To examine this hypothesis, we isolated phenotypically defined cells from murine skeletal muscle and cultured these cells under different conditions tailored to promote differentiation into several cell types including myocytes. We report here that in conditions permissive for hematopoietic differentiation, muscle-derived CD45(-)Sca-1(+)c-kit(-) cells differentiated into cells expressing hematopoietic-specific mRNA; while in conditions promoting myogenic, neuronal, and adipocytic differentiation, cells morphologically typical of these cell types expressing tissue-specific markers were identified 9-14 days in culture. When CD45(-)Sca-1(+)c-kit(-) cells from muscle or bone marrow were transplanted intracerebellarly into Purkinje cell degenerative (pcd) mice, the behavior of these mice improved 28 days after transplantation relative to mice injected with vehicle alone, suggesting that these cells contributed to the appearance of functional neuronal cells that may have improved the ataxic condition characteristic of these mice. Phenotypic analysis of single cell suspensions prepared from brain, blood, and intestinal epithelium revealed the presence of CD45(-)Sca-1(+)c-kit(-) cells in varying degrees. These studies suggest that a phenotypically common, multipotent cell can be identified in different tissues and that this cell may represent a universal pluripotent stem cell residing at different levels in multiple murine tissues.

Animals↗
PubMed2002

Influence of chromatographic conditions on separation in comprehensive gas chromatography.

Comprehensive gas chromatography (GC x GC) is now established as a powerful technique, which offers unprecedented separation power. For complex samples, the distribution of peaks in the two-dimensional (2D) space still may need to be optimised. Since temperature (T) is a critical variable, and compounds can be shifted in relative positions on column 1 arising from temperature program rate (rT) changes, and since retention in the second dimension, D2 (2tR) is likewise affected by the prevailing T (elution temperature; Te), then any factors which alter Te will affect the extent of separation in D2. Since temperature program and carrier gas velocity rate will affect the Te of the solutes, these two factors are considered in this paper. Apart from these two parameters, results of different stationary phase choice for the second dimension column as well as the second dimension column length are reported. rT is found to have the most profound impact on the Te of solutes and will be more likely to cause an inversion of elution order if such behaviour can occur. Peak widths and 2tR increase with a decrease in Te. On the other hand, flow-rate has less impact on peak widths and 2tR although Te is affected by a change in flow-rate. Specific solute-stationary phase interactions will cause the elution order of certain solutes to be altered, and may be observed when a different stationary phase is employed as the second column, depending on the solute-stationary phase separation mechanism. Experiments conducted on different second dimension column length showed that although a longer column will lead to better separations, wrap-around may confound the separation process and may cause the solutes from sequential modulation events to co-elute. Thus a suitable second dimension column phase and length must be employed in order to obtain good separation. The factors investigated in this study will cause different extents of changes in the solute elution order and solute separations, and will affect the 2D contour presentation.

Chromatography, Gas↗
PubMed2002

Virus-specific CTL responses induced by an H-2K(d)-restricted, motif-negative 15-mer peptide from the fusion protein of respiratory syncytial virus.

We describe 15-mer peptide P8:F92-106 from the F protein of respiratory syncytial virus (RSV) that can act as an MHC class I-restricted (H-2K(d)) epitope for RSV-specific CD8(+) CTL. This peptide is interesting because not only is it the first murine CTL epitope to be identified in the F protein but also because it does not contain a known allele-specific motif, as all 15 amino acids appear to be required for effective presentation to CTL. In in vitro MHC class I refolding experiments, peptide P8:F92-106 induced complex formation with H-2K(d) heavy chains and beta2-microglobulin. Immunization of BALB/c mice with P8:F92-106 resulted in the induction of peptide and RSV-specific CTL responses as well as peptide-specific proliferative responses. Following intranasal challenge with RSV, P8:F92-106-immunized mice showed a significant reduction in viral load in the lungs compared to that seen in unimmunized mice. Furthermore, passive transfer of purified CD8(+) lymphocytes into BALB/c scid mice prior to challenge with RSV also resulted in a reduction in the virus load in lungs of challenged mice. These results indicate the potential of synthetic peptide epitopes for the induction of protective immune responses against RSV infection.

Amino Acid Sequence↗
PubMedDate not supplied

Comparison of endoscopic sinus surgery with and without image guidance.

BACKGROUND: Image guidance based on preacquired computed tomography scans of the patient is a technique used to assist the physician during endoscopic sinus surgery (ESS). This study seeks to compare ESS with and without image guidance, analyzing a number of parameters that can impact on efficacy. METHODS: Retrospective chart review took place at a tertiary care referral center. The study group consisted of 97 consecutive patients confirmed to have undergone ESS using an electromagnetic intraoperative image guidance system (IGS). The control group consisted of 61 consecutive patients who underwent ESS, before the IGS was available at the study hospital. The main outcomes measured were analysis of patient profile, including coexisting conditions such as asthma and polyposis, assessment of which specific sinuses underwent surgical treatment; major and minor complications; estimated blood loss (EBL); operative time; and the need for repeat surgery. RESULTS: The IGS group had 74% of patients with polyposis; more sinuses, on average, which underwent surgical revision; one major and three minor complications; an average EBL of 134 cc, an average procedure time of 154 minutes; and one patient who needed repeat surgery in a 3-month follow-up period. The non-IGS group had 40% of patients with polyposis; seven major complications and one minor complication; an average EBL of 94 cc; and three patients who needed repeat surgery within 3 months. CONCLUSIONS: The use of an IGS for endoscopic sinus surgery may reduce the complications associated with the procedure and allow for a more thorough operation. However, operative time and EBL may be increased.

Adult↗