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R Jones

Publications and source records attributed to R Jones.

At least 19 recordsLinked to original sources
PubMed2006

Assessing the impact of nutrient enrichment in estuaries: susceptibility to eutrophication.

The main aim of this study was to develop a generic tool for assessing risks and impacts of nutrient enrichment in estuaries. A simple model was developed to predict the magnitude of primary production by phytoplankton in different estuaries from nutrient input (total available nitrogen and/or phosphorus) and to determine likely trophic status. In the model, primary production is strongly influenced by water residence times and relative light regimes. The model indicates that estuaries with low and moderate light levels are the least likely to show a biological response to nutrient inputs. Estuaries with a good light regime are likely to be sensitive to nutrient enrichment, and to show similar responses, mediated only by site-specific geomorphological features. Nixon's scale was used to describe the relative trophic status of estuaries, and to set nutrient and chlorophyll thresholds for assessing trophic status. Estuaries identified as being eutrophic may not show any signs of eutrophication. Additional attributes need to be considered to assess negative impacts. Here, likely detriment to the oxygen regime was considered, but is most applicable to areas of restricted exchange. Factors which limit phytoplankton growth under high nutrient conditions (water residence times and/or light availability) may favour the growth of other primary producers, such as macrophytes, which may have a negative impact on other biological communities. The assessment tool was developed for estuaries in England and Wales, based on a simple 3-category typology determined by geomorphology and relative light levels. Nixon's scale needs to be validated for estuaries in England and Wales, once more data are available on light levels and primary production.

Environmental Monitoring↗
PubMed2006

E center in silicon has a donor level in the band gap.

It has been an accepted fact for more than 40 years that the E center in Si (the group-V impurity--vacancy pair)--one of the most studied defects in semiconductors--has only one energy level in the band gap: namely, the acceptor level at about 0.45 eV below the conduction band. We now demonstrate that it has a second level, situated in the lower half of the band gap at 0.27 eV above the valence band. The existence of this level, having a donor character, is disclosed by a combination of different transient-capacitance techniques and electronic-structure calculations. The finding seriously questions some diffusion-modeling approaches performed in the past.

Journal Article↗
PubMed2006

Physical and psychological co-morbidity in irritable bowel syndrome: a matched cohort study using the General Practice Research Database.

BACKGROUND: Irritable bowel syndrome is a common problem known to have a complex relationship with psychological disorders and other physical symptoms. Little information, however, is available concerning physical and psychological comorbidity in irritable bowel syndrome patients studied over an extended period. AIM: To evaluate physical and psychological morbidity 2 years before and during 6 years after the time of diagnosis in incident cases of irritable bowel syndrome and control subjects. METHODS: A matched cohort study was implemented in 123 general practices using the General Practice Research Database. Irritable bowel syndrome cases (n = 1827) and controls (n = 3654) were compared for 2 years before and 6 years after diagnosis. RESULTS: The age-standardized incidence of irritable bowel syndrome in patients over 15 years of age was 1.9 per 1,000 in men and 5.8 per 1,000 in women. From 2 years before the date of diagnosis, more irritable bowel syndrome cases (13%) than controls (5%) consulted with depression or were prescribed antidepressant drugs. Consultation and prescription rates for anxiety were also higher before diagnosis, and both anxiety and depression remained prevalent up to 6 years after diagnosis. Asthma, symptoms of urinary tract infection, gall-bladder surgery, hysterectomy and diverticular disease were recorded more frequently in irritable bowel syndrome patients, who were also more likely than controls to be referred to hospital. CONCLUSIONS: People who are diagnosed with irritable bowel syndrome experience more anxiety and depression and a range of physical problems, compared with controls; they are more likely to be referred to hospital.

Adolescent↗
PubMed2006

Irritable bowel syndrome: the burden and unmet needs in Europe.

Irritable bowel syndrome affects approximately 10-15% of the European population, although prevalence rates vary depending on the classification used and the country surveyed. This may be due to differences in patterns of medical care and diagnosis of the condition. Up to 70% of individuals with irritable bowel syndrome may not have been formally diagnosed. The disorder affects 1.5-3 times as many women as men and poses a significant economic burden in Europe, estimated at euro 700-euro 1600 per person per year. It also reduces quality of life and is associated with psychological distress, disturbed work and sleep, and sexual dysfunction. It is a chronic disorder, which affects many individuals for more than 10 years. Most patients are managed in primary care, although some are referred to gastroenterologists and other specialists. Patients with irritable bowel syndrome undergo more abdomino-pelvic surgery than the general population. We propose that a positive diagnosis of the condition may avoid the delay in diagnosis many patients experience. We conclude that, in Europe, there are significant unmet needs including lack of familiarity with irritable bowel syndrome, difficulties in diagnosis and lack of effective treatments for the multiple symptoms of the disorder. The development of pan-European guidelines for irritable bowel syndrome will benefit patients with this condition in Europe.

Cost of Illness↗
PubMed2006

Skin conductance monitoring compared with bispectral index monitoring to assess emergence from general anaesthesia using sevoflurane and remifentanil.

BACKGROUND: Changes in skin conductance have previously been reported to correlate well with plasma levels of stress hormones and awakening stimuli. In this study, monitoring of skin conductance during emergence from general anaesthesia was compared with the monitoring of bispectral index (BIS). METHODS: Twenty-five patients undergoing minor elective surgery were investigated. The number of fluctuations in mean skin conductance (NFSC), BIS and haemodynamic parameters were recorded simultaneously. The performance of the monitoring devices to predict and distinguish between the clinical states 'steady-state anaesthesia', 'first reaction' and 'extubation' were compared using the method of prediction probability (P(K)) calculation. RESULTS: Both monitors showed similar performance in distinguishing between 'steady-state anaesthesia' vs 'first reaction' (P(K) NFSC 0.89; BIS 0.94) and 'steady-state anaesthesia' vs 'extubation' (P(K) NFSC 0.96; BIS 0.96). The response times of the monitors, to indicate the likelihood of 'first reaction', were not significantly different. CONCLUSIONS: NFSC, as a parameter of skin conductance, performed similarly to BIS in patients waking after a general anaesthetic.

Adolescent↗
PubMed2006

Chk1-dependent slowing of S-phase progression protects DT40 B-lymphoma cells against killing by the nucleoside analogue 5-fluorouracil.

Chk1 plays a crucial role in the DNA damage and replication checkpoints in vertebrates and may therefore be an important determinant of tumour cell responses to genotoxic anticancer drugs. To evaluate this concept we compared the effects of the nucleoside analogue 5-fluorouracil (5FU) on cell cycle progression and clonogenic survival in DT40 B-lymphoma cells with an isogenic mutant derivative in which Chk1 function was ablated by gene targeting. We show that 5FU activates Chk1 in wild-type DT40 cells and that 5FU-treated cells accumulate in the S phase of the cell cycle due to slowing of the overall rate of DNA replication. In marked contrast, Chk1-deficient DT40 cells fail to slow DNA replication upon initial exposure to 5FU, despite equivalent inhibition of the target enzyme thymidylate synthase, and instead accumulate progressively in the G1 phase of the following cell cycle. This G1 accumulation cannot be reversed rapidly by exogenous thymidine or removal of 5FU, and is associated with increased incorporation of 5FU into genomic DNA and severely diminished clonogenic survival. Taken together, these results demonstrate that a Chk1-dependent replication checkpoint which slows S phase progression can protect tumour cells against the cytotoxic effects of 5FU.

Cell Cycle↗
PubMed2006

Effects of legume forages on ovine gastrointestinal parasite development, migration and survival.

Lambs grazing certain legumes have reduced parasite intensities compared to lambs grazing ryegrass swards. Eighteen replicates of white clover (cv. AberHerald), lucerne (cv. Luzelle), red clover (cv. Merviot) and perennial ryegrass (cv. Abersilo) were sown at equivalent field rates in 25 cm diameter PVC pots and maintained outside for 6 months. On day 0, forage in each pot was cut to 50 mm from soil level and the pots were placed in a glasshouse (at 19-25 degrees C and 70% humidity) in a randomised block design. Ten grams sheep faeces containing 2,133 Haemonchus contortus eggs per gram were placed on the soil in each pot. Six replicates of each forage were destructively sampled on days 14, 21 and 29. Forage samples were cut at 50 mm from the soil surface and at the soil surface to give two samples per pot. The number of nematodes was determined by a modification of the Whitehead tray method. The ratio of free-living to infective-stage larvae was determined from at least 10% of the larvae. The number of H. contortus larvae kgdrymatter(-1) (DM) forage was calculated and the data rank transformed prior to analysis by ANOVA. There were fewer larvae on legumes compared with ryegrass on samples from forage above 50 mm (P<0.001) but there was no forage effect on larvae below this height. The sum of larvae present on all forage per kilogram DM showed fewer larvae on red clover compared with ryegrass on day 21 (P<0.05). There was an effect of day on the total number of larvae on forage (P<0.001) but there were no foragexday interactions. Analysis of the data according to the leaf area above 50 mm from the soil surface confirmed these results, that there were fewer larvae on legume forages than ryegrass above this height (P<0.01). Overall, red clover affected the development of H. contortus and all legumes affected larval migration above 50 mm compared with ryegrass but survival of larvae was similar on all forages. Further work is needed to determine if these effects of legume forages would reduce the number of parasitic larvae ingested by livestock under field conditions.

Animal Migration↗
PubMed2006

Severe persistent sciatic pain and weakness due to a gluteal artery pseudoaneurysm as a complication of bone marrow biopsy.

Complications of bone marrow trephine are thought to be uncommon. Herein, we present a case of severe debilitating sciatic nerve palsy secondary to a gluteal artery pseudoaneurysm following bone marrow biopsy. The pseudoaneurysm was treated successfully by percutaneous embolization; however, the patient remains significantly impaired with persistent painless foot drop.

Aneurysm, False↗
PubMed2006

A novel triple purge strategy for eliminating chronic myelogenous leukemia (CML) cells from autografts.

Imatinib-refractory chronic myelogenous leukemia (CML) patients can experience long-term disease-free survival with myeloablative therapy and allogeneic hematopoietic cell transplantation; however, associated complications carry a significant risk of mortality. Transplantation of autologous hematopoietic cells has a reduced risk of complications, but residual tumor cells in the autograft may contribute to relapse. Development of methods for purging tumor cells that do not compromise the engraftment potential of the normal hematopoietic cells in the autograft has been a long-standing goal. Since primitive CML cells differentiate more rapidly in vitro than their normal counterparts and are also preferentially killed by mafosfamide and imatinib, we examined the purging effectiveness on CD34(+) CML cells using a strategy that combines a brief exposure to imatinib (0.5-1.0 microM for 72 h) and then mafosfamide (30-90 microg/ml for 30 min) followed by 2 weeks in culture with cytokines (100 ng/ml each of stem cell factor, granulocyte colony-stimulating factor and thrombopoietin). Treatment with 1.0 microM imatinib, 60 microg/ml mafosfamide and 14 days of culture with cytokines eliminated BCR-ABL(+) cells from chronic phase CML patient aphereses, while preserving normal progenitors. This novel purging strategy may offer a new approach to improving the effectiveness of autologous transplantation in imatinib-refractory CML patients.

Antigens, CD↗
PubMed2006

Gene expression profiling in lung tissues from mice exposed to cigarette smoke, lipopolysaccharide, or smoke plus lipopolysaccharide by inhalation.

The purpose of this study was to investigate whether coexposure to lipopolysacchride (LPS) will heighten the inflammatory response and other pulmonary lesions in mice exposed to cigarette smoke, and thus to evaluate the potential use of this LPS-compromised mouse model as a model for chronic obstructive pulmonary disease (COPD) investigation. AKR/J male mice were exposed to HEPA-filtered air (sham control group), cigarette smoke (smoke group), LPS (LPS group), or smoke plus LPS (smoke-LPS group) by nose-only inhalation. Lungs were collected at the end of the 3-wk exposure and processed for microarray analysis. Clustering and network analysis showed decreased heat-shock response and chaperone activity, increased immune and inflammatory response, and increased mitosis in all three exposed groups. Two networks/function modules were exclusively found in the smoke-LPS group, that is, the downregulated muscle development/muscle contraction process and the upregulated reactive oxygen species production process. Notably, the number of genes and function modules/networks associated with inflammation was reduced in the smoke-LPS group compared to the LPS group. The most upregulated gene in the smoke group, MMP12, is a matrix metalloproteinase that preferentially degrades elastin and has been implicated in COPD development. NOXO1, which was upregulated in all three treatment groups, positively regulates the expression of a subunit of NADPH oxidase (NOX1), a major source of reactive oxygen species, and may play an important role in the pathogenesis of COPD. Serum amyloid A1, which is an acute-phase systemic inflammation marker and can be induced by LPS exposure, was significantly upregulated in the LPS and smoke-LPS groups. MARCO, a scavenger receptor expressed in macrophages that may play a significant role in LPS-induced inflammatory response, was upregulated in the LPS group and the smoke-LPS group, but not in the smoke group. In conclusion, gene expression profiling identified genes and function modules that may be related to COPD pathogenesis and may be useful as biomarkers to monitor COPD progression. In addition, an LPS-compromised mouse model showed potential as a useful tool for studying cigarette smoke-associated COPD.

Administration, Inhalation↗
PubMed2006

Ex vivo expansion of mafosfamide-purged PBPC products.

BACKGROUND: Multiple studies have demonstrated that 'purging' of autografts with 4-hydroperoxycyclophosphamide (4HC) or the related compound mafosfamide (Mf), to eradicate residual leukemia, produces the best results associated with autologous blood and marrow transplantation for AML. However, 4HC purging results in prolonged aplasia. Therefore, we evaluated the potential of ex vivo expansion of Mf-treated CD34+ cells from mobilized PBPC. METHODS: CD34+ cells were isolated from PBPC products and treated with 30 microg/mL Mf. The Mf-treated CD34+ cells were washed and cultured for 14 days in StemLine II-defined media containing recombinant human (rh) SCF, G-CSF and thrombopoietin (Tpo). RESULTS: Treatment with Mf resulted in 90% killing of progenitor cells (GM-CFC) but maintenance of SCID-repopulating cells (SRC). Ex vivo culture of the Mf-treated CD34+ cells resulted in decreased cell numbers (10-20% of the starting cell dose) during the first week. Nevertheless, in the second week of culture the total cell numbers expanded to approximately 20-fold above starting cell numbers and progenitor cells returned to approximately pre-treatment levels. DISCUSSION: These studies demonstrate the potential of ex vivo culture to expand both total cell numbers and progenitor cells following treatment of PBPC CD34+ cells with Mf. Clinical studies are currently being initiated to evaluate the engraftment potential of these purged and expanded products.

Adjuvants, Immunologic↗
PubMed2006

Assessment of the impact sound in golf putting.

The influence of impact sound in putting on players' perceptions of "feel" is explored in this paper. Tests were conducted to investigate the impact sound characteristics of five different ball types using two different putter types. The first test studied the impact sound of purely the ball, while the second test investigated the influence of putter construction and impact location on impact sound for the different ball types. Trends were found between sound spectra peaks in the 2 - 4 kHz range and the compression values of the balls. In addition, frequency content was more dependent on putter type and impact location than on ball construction in the 0 - 2 kHz range. The final test employed a paired comparison technique to investigate players' perceptions of sharpness and loudness of impact sound, ball speed from the clubface and ball hardness. Relationships between the subjective data and the sound characteristics of the balls were then examined. It was found that the ball the players' perceived to have the sharpest and loudest sound, to feel the hardest and to come off the clubface the quickest also had the largest calculated values of loudness and sharpness and had a spectral peak at a higher frequency than the other balls.

Auditory Perception↗
PubMed2006

Novel anti-hepatitis B agents: A focus on telbivudine.

Although preventable by vaccination, hepatitis B infection is common, affecting more than 350 million individuals worldwide. Chronic hepatitis B infection is associated with the complications of chronic liver disease including cirrhosis and hepatocellular carcinoma. Current agents designed to target hepatitis B are hindered by the development of resistance, poor tolerability or limited efficacy and a demand for new agents and strategies continues. This review focuses on telbivudine, a novel agent in the fight against hepatitis B.

Antiviral Agents↗
PubMed2006

Authorship of research papers: ethical and professional issues for short-term researchers.

Although the International Committee of Medical Journal Editors has published clear guidance on the authorship of scientific papers, short-term contract research workers, who perform much of the research that is reported in the biomedical literature, are often at a disadvantage in terms of recognition, reward and career progression. This article identifies several professional, ethical and operational issues associated with the assignment of authorship, describes how a university department of primary care set about identifying and responding to the concerns of its contract research staff on authorship and describes a set of guidelines that were produced to deal with the ethical and professional issues raised. These guidelines include directions on how authorship should be negotiated and allocated and how short-term researchers can begin to develop as authors. They also deal with the structures required to support an equitable system, which deals with the needs of short-term researchers in ways that are realistic in the increasingly competitive world of research funding and publication, and may offer a model for more formal guidelines that could form part of institutional research policy.

Authorship↗