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Biomedical subjects

P Gilbert

Publications and source records attributed to P Gilbert.

At least 19 recordsLinked to original sources
PubMed2006

The relation of entrapment, shame and guilt to depression, in carers of people with dementia.

There is increasing research exploring depression in carers of people with dementia. This study explored the relation of entrapment, shame and guilt to depression in a group of 70 carers of those with dementia. As in other studies the experience of entrapment in the role was highly related to depression. Moreover, experiences of shame relating to self-criticism, other people's expectations and the fear of their criticism were significantly related to depression, entrapment and guilt. Guilt however, as focused on the fears of harming others, letting others down and sense of responsibility, was not associated with depression or entrapment. Depression in carers may relate in part to feeling trapped in a role but also being vulnerable to criticism and feelings of inadequacy in that role. In this study, degree of behavioural disturbance/dependence was not found to be significantly associated with any of the research variables.

Caregivers↗
PubMed2006

Effects of chronic triclosan exposure upon the antimicrobial susceptibility of 40 ex-situ environmental and human isolates.

BACKGROUND: Triclosan (TCS) exposure of Escherichia coli selects for tolerant clones, mutated in their enoyl-acyl carrier protein reductase (FabI). It has been inferred that this phenomenon is widespread amongst bacterial genera and might be associated with resistance to third party agents. METHODS: Ex-situ, low passage isolates of enteric, human axilla, human oral origin and bacteria isolated from a domestic drain, together with selected type cultures were exposed to escalating concentrations of TCS over 10 passages using a gradient plate technique. One fresh faecal isolate of E. coli was included as a positive control. TCS susceptibility was determined for all strains before and after exposure, whilst enteric isolates were additionally assessed for susceptibility towards chlorhexidine, tetracycline, chloramphenicol, nalidixic acid and ciprofloxacin, and the oral isolates towards chlorhexidine, tetracycline and metronidazole. RESULTS: Triclosan exposure of E. coli markedly decreased TCS susceptibility. TCS susceptibility also decreased for Klebsiella oxytoca, Aranicola proteolyticus and Stenotrophomonas maltophilia. Susceptibility of the remaining 35 strains to TCS and the other test agents remained unchanged. CONCLUSIONS: These data suggest that selection for high level resistance by TCS exposure is not widespread and appears to be confined to certain enteric bacteria, especially E. coli. Change in TCS susceptibility did not affect susceptibility towards chemically unrelated antimicrobials. SIGNIFICANCE AND IMPACT: Acquired high-level TCS resistance is not a widespread phenomenon.

Anti-Infective Agents, Local↗
PubMed2006

Individual microflora beget unique oral microcosms.

AIMS: To examine the efficacy of the multiple Sorbarod device (MSD) for the reproduction of inter-individual variations in oral microbiotas. The MSD supports sessile growth on parallel cellulose filters, perfused with artificial saliva. This enables biofilms (BF) to be grown and sampled, together with released cells in eluted medium (perfusates, PAs). METHODS AND RESULTS: Two sets of triplicate MSDs were established. One set was inoculated using fresh saliva from three separate volunteers; the second set was inoculated from one saliva donor. Both were incubated in an anaerobic cabinet. BF and PA were analysed at 24-h intervals by PCR-denaturing gradient gel electrophoresis (DGGE) of 16S rDNA. Hierarchical dendrograms were constructed in order to sort community fingerprints over time, based on community relatedness. The MSD supported complex oral communities, as evidenced by DGGE (>20 distinct DGGE bands) and confocal scanning laser microscopy. DGGE band sequencing revealed bacteriological diversity and a high incidence of anaerobic species, including Prevotella sp. Dendrograms demonstrated marked inter-individual variation in the relative species abundance within salivary inocula from different volunteers (DV) and each associated MSD (all >45%, majority c. 85% concordance). Less variation was shown between triplicate models established using saliva from a single volunteer (SV) (all >58%; majority c. 95% concordance). PAs clustered together with the associated biofilms and inocula in the majority of cases for the DV MSDs whilst SV MSD community profiles clustered between replicate MSDs. CONCLUSIONS: Data indicate that marked inter-individual variations in human salivary composition can be partially replicated in individualized MSD microcosms. SIGNIFICANCE AND IMPACT OF THE STUDY: This study demonstrates the in vitro reproduction of individual oral microbiotas and suggests that taking inter-individual variability into account will increase the relevance of microcosm studies.

Bacterial Typing Techniques↗
PubMed2006

Parental recall, attachment relating and self-attacking/self-reassurance: their relationship with depression.

OBJECTIVES: When things go wrong for people they can become self-critical or focus on positive, reassuring aspects of the self. This study explored the relationship between forms of self-criticism and self-reassurance, recall of parental experiences and attachment style in relation to depressed symptoms in students. METHODS: A sample of 197 undergraduate students from the UK and Canada completed self-report questionnaires measuring recall of parental styles, attachment, forms of self-criticism, self-reassurance, and depression symptoms. RESULTS: Recall of parents as rejecting and overprotecting was significantly related to both inadequacy and self-hating self-criticism. In contrast, parental warmth was negatively correlated with these forms of self-criticism. In addition, when things go wrong for the person, recall of parental warmth was associated with the ability to be self-reassuring. A mediator analysis suggested that (I) the impact of recall of negative parenting on depression is mediated through the forms of self-criticism and (2) the effect of parental warmth on depression was mediated by the ability to be self-reassuring. CONCLUSIONS: The impacts of negative parenting styles may translate into vulnerabilities to depression via the way children (and later adults) develop their self-to-self relating (e.g. as self-critical versus self-reassuring). Hence, there is a need for further research on the link between attachment experiences, recall of parental rejection/warmth and their relationship to internal, self-evaluative and affect systems in creating vulnerabilities to psychopathology.

Adult↗
PubMed2006

Interpersonal sensitivities: their links to mood, anger and gender.

This paper explores two interpersonal sensitivities (to rejection and to social put-down) in a group of 54 depressed men and 50 depressed women. Measures of anhedonia, anxiety, anger, social comparison, and submissive behaviour were also obtained. We found no differences in rejection sensitivity, anger, anhedonia, or anxiety between the sample of depressed men and women. Depressed women rated themselves as more submissive and more inferior than depressed men, and blamed themselves more for being criticized and put-down by other people. Principal components analysis (PCA) revealed three underlying factors: mood (including anxiety and depression), internalization (related to self-blame and feelings of low rank), and externalization (related to anger and blaming others for criticism). For both men and women internalization was significantly correlated with depression. However, externalization was negatively related to depression in women, but positively related to depression in men.

Adult↗
PubMed2005

Evolved mechanisms in adolescent anxiety and depression symptoms: the role of the attachment and social rank systems.

One hundred and forty adolescent students were assessed on measures of attachment, social rank (social comparison and submissive behaviour), and depression and anxiety symptoms. Secure attachment was significantly correlated with positive social comparison and inversely with submissive behaviour, depression and anxiety symptoms. In contrast, insecure attachment of both avoidance and ambivalence was associated with unfavourable comparison with others, and positively correlated with submissive behaviour, depression and anxiety symptoms. Exploring the relationship of attachment with depression and anxiety symptoms revealed that this link might have different routes through social rank perceptions. For secure attachment, social rank concerns (i.e. social comparison and submissive behaviour) did not mediate the linkage with anxiety or depression symptoms. However, for insecure attachment, social rank concerns showed either a partial or complete mediation of these relationships. This data may indicate that insecure attachment sensitizes individuals to become focused on the competitive dynamics of groups, the power of others to shame, hurt or reject, and the need to defend against these possibilities.

Adolescent↗
PubMed2005

Adhaeribacter aquaticus gen. nov., sp. nov., a Gram-negative isolate from a potable water biofilm.

A Gram-negative bacterium was isolated from a freshwater biofilm developed on a stainless steel surface under a fluid velocity of 0.26 m s(-1). The strain, MBRG1.5(T), was cultivated on R2A agar and formed pink colonies. Light microscopy and negative staining in a transmission electron microscope showed that the cells were rod-shaped, approximately 2.8-4.1 microm long by 0.9-1.7 microm wide in size and produced large quantities of extracellular fibrillar material. Additionally, following growth in batch culture, transmission electron microscopy showed that many cells plasmolysed. Stationary-phase cells were more variable in size and shape. The DNA G+C content was 40.0 mol%. The most abundant fatty acids were 15 : 0 iso (22.5 %), followed by 16 : 1omega5c (16.9 %) and 15 : 0 iso 2-OH (16.5 %). Phylogenetic analysis of the 16S rRNA gene showed that the strain was a member of the family 'Flexibacteraceae' of the Cytophaga-Flavobacterium-Bacteroides group. Phenotypic and genotypic analyses indicated that the strain could not be assigned to any recognized genus; therefore a novel genus and species, Adhaeribacter aquaticus gen. nov., sp. nov., is proposed, with MBRG1.5(T) (=DSM 16391(T)=NCIMB 14008(T)) as the type strain.

Base Composition↗
PubMed2005

Protozoan grazing and its impact upon population dynamics in biofilm communities.

AIMS: To determine the impact of protozoan grazing on the population dynamics of a multispecies bacterial biofilm community. METHODS AND RESULTS: Grazing by Acanthamoeba castellanii and the ciliate Colpoda maupasi upon biofilm and planktonic communities, composed of Klebsiella pneumoniae, Pseudomonas fluorescens and Staphylococcus epidermidis was investigated. Biofilms were formed using glass coverslips, held in a carousel device, as substrata for biofilm formation or in glass flow cells. The predatory effects of the amoeba were generally confined to the biofilm, where grazing rates corresponded to losses from the biofilm equivalent to ca 30,000 biofilm cells cm(-2) h(-1), with the amoeba becoming an integral part of the community. C. maupasi reduced the thickness of mature multispecies biofilms at steady-state from 500 to <200 microm. CONCLUSIONS: We report that the presence of the protozoa A. castellanii and C. maupasi markedly influence population dynamics within defined biofilm communities. SIGNIFICANCE AND IMPACT OF THE STUDY: The current study dispels the popular opinion that biofilms are protected against predation by protozoa. A. castellanii clearly has the capacity to graze mixed biofilm communities and to become integrally associated with them, whereas the ciliate C. maupasi reduced biofilm thickness by up to 60%.

Acanthamoeba↗
PubMed2005

Development and characterization of a simple perfused oral microcosm.

AIMS: To validate perfused, inline, filter-based fermentation systems (multiple Sorbarod devices, MSD) for their ability to maintain stable oral bacterial communities. MSD enable replicate (n=5) microcosm biofilms (BF) to be established and sampled, together with their perfusates (PA, cells in eluted medium). METHODS AND RESULTS: Fresh saliva from human volunteers was used to inoculate MSD, incubated in an anaerobic cabinet and perfused with artificial saliva at 7 ml h(-1). BF within Sorbarod filters and cells eluted in the PA were analysed at 24-h intervals by differential bacteriological culture and checkerboard DNA-DNA hybridization (CKB, 40 oral species). Dynamic stability was apparent after 2-3 days within both BF and PA as evidenced by culture, CKB data and pH measurements. BF harboured large numbers of anaerobic species and facultative anaerobes [ca 10-11 log10 colony-forming units (CFU)/filter] comprising considerable numbers of streptococci and Gram-negative species. PA contained ca 9-10 log(10) CFU ml(-1) suggesting an apparent mean growth rate of 0.1 h(-1) for the BF, as a whole corresponding to a mean generation time of 10 h. CKB analysis revealed considerable bacterial diversity within the respective MSD. Inter-individual variations in the relative species abundance of inocula was broadly reproduced in the MSD (BF and PA), although considerable variation was apparent between triplicate models established using saliva from one saliva donor or from three individual donors. The dominance of Gram-negative species, indicated by culture was supported by CKB analysis (major species, Prevotella melaninogenica and Fusobacterium nucleatum). CONCLUSIONS: Data obtained from the various analytical approaches showed a high degree of congruence. The MSD enables the maintenance of complex, stable salivary microcosms and represents a simple, reproducible tool for modelling individual oral bacterial ecosystems. SIGNIFICANCE AND IMPACT OF THE STUDY: This study demonstrates the utility of the MSD for studying the micro-ecology of the oral cavity.

Bacteria↗
PubMed2004

[NOEMIE: an epidemiological study of migraine at work: results from 17 occupational health centres].

INTRODUCTION: A survey (NOEMIE, Nouvel Observatoire Epidemiologique de la Migraine en Entreprise) was carried out in France in 17 occupational healthcare units in order to identify subjects suffering from migraine headache with the aim of guiding them towards a healthcare program. The data collected in the participating units are presented. METHODS: and patients. NOEMIE was a national cross-sectional, observational, multicentric study with a 6-month follow-up. Two groups of migraine sufferers (according to IHS criteria) were included and divided into two groups: subjects already managed for their migraine (group A) and subjects who had not sought healthcare for migraine for more than 12 months (group B). The main objective was to evaluate changes in the quality-of-life score (QVM) 6 months later. RESULTS: At inclusion, the two groups were comparable for demographic features, history of migraine, and disease severity. A significant difference was observed between the two groups for frequency of attacks, disease management, and evaluation of treatment efficacy and of quality-of-life. At 6 months, patient satisfaction and quality-of-life were significantly improved (6 to 10 point improvement). For the 4753 reported attacks, 12.4 percent of the patients in group A required sick leave versus 10.9 percent in group B. Frequency of sick leave was considerably improved in both groups. CONCLUSION: By identifying subjects suffering from migraine headache who had not sought specific medical care and advising them to seek medical management, the employee healthcare units improved the subjects' quality-of-life, promoted adequate medical management and reduced occupational consequences of migraine headache.

Adult↗
PubMed2004

Immigration and emigration of Burkholderia cepacia and Pseudomonas aeruginosa between and within mixed biofilm communities.

AIMS: To investigate the dynamics of binary culture biofilm formation through use of both the Sorbarod model of biofilm growth and the constant depth film fermenter (CDFF). METHODS AND RESULTS: Pseudo steady-state biofilm cultures of laboratory and clinical strains of Pseudomonas aeruginosa, selected on the basis of their ability to produce a Burkholderia cepacia growth-inhibitory substance, were established on Sorbarod filters and challenged with corresponding planktonic grown cultures of B. cepacia. Reverse challenges were also conducted. Both B. cepacia and P. aeruginosa were able to form steady-state monoculture biofilms after 48 h growth. When steady-state biofilms of B. cepacia NTCT 10661 were challenged with planktonically grown P. aeruginosa PAO1 known to produce a B. cepacia growth-inhibitory substance, the immigrant population was rapidly and almost completely bound to the biofilm, displacing B. cepacia. By contrast, established biofilms of P. aeruginosa PAO1 resisted immigration of B. cepacia 10661. Similar experiments conducted with a nongrowth inhibitory substance producing clinical pairing of P. aeruginosa 313113 and B. cepacia 313113 led to the formation of stable, mixed biofilm populations in both instances. Moreover, co-inoculation with these clinical isolates resulted in a stable, mixed steady-state biofilm. Similar observations were made for biofilms generated in CDFFs. In such instances following pan-swapping between two monoculture CDFFs, B. cepacia 313113 was able to integrate into an established P. aeruginosa 313113 biofilm to form a stable binary biofilm. CONCLUSIONS: Establishment of a mixed species community follows a specific sequence of inoculation that may either be due to some degree of match between co-colonizers or that P. aeruginosa predisposes uncolonized sections of the surface to permit B. cepacia colonization. SIGNIFICANCE AND IMPACT OF THE STUDY: Colonization of a surface with one bacterial species confers colonization resistance towards other species. Disinfection of a surface might well increase the probability of pathogen harbourage.

Bacteriological Techniques↗
PubMed2004

A rapid method for the evaluation of both extrinsic and intrinsic contamination and resulting spoilage of water-in-oil emulsions.

AIMS: To develop a method for studying the microbial spoilage of water-in-oil emulsions and to use this to investigate (i) the intrinsic stability of water-in-oil formulations and (ii) Pseudomonas aeruginosa SP1-induced spoilage of a proprietary emulsion. METHODS AND RESULTS: Aliquots of test emulsion were placed into wells of a microtitre plate and the opacity (492 nm) monitored at 120-min intervals over several hours. Cracking of the emulsion was associated with marked reductions in opacity. Rate and extent of change in O.D. could be used as indicators of spoilage. Spoilage of a laboratory emulsion formulation was investigated where microorganisms with demonstrated spoilage potential were incorporated either into the water phase prior to emulsification or where the proportion of contaminated water droplets was varied by dilution of contaminated emulsion with a sterile formulation. Results suggested that the route of introduction was a critical determinant of the probability of gross spoilage. Ps. aeruginosa SP1-induced spoilage of a proprietary formulation was found to be independent of growth in the formulation; rather it was attributed to the presence of a heat-labile extracellular spoilage-factor that was protease labile and possessed both lipase and polysorbate hydrolytic activity. Such spoilage potential was unique to one Ps. aeruginosa culture filtrate amongst five pseudomonads tested. SIGNIFICANCE AND IMPACT OF THE STUDY: The method is both rapid and reproducible, enables evaluation of the effects of route of contamination upon emulsion spoilage and has potential application in formulation development for cosmetic, pharmaceutical and food products.

Colony Count, Microbial↗
PubMed2004

Influence of growth environment on coaggregation between freshwater biofilm bacteria.

AIM: To characterize the expression of coaggregation between Blastomonas natatoria 2.1 and Micrococcus luteus 2.13 following growth in liquid culture, on agar and in an artificial biofilm matrix composed of poloxamer hydrogel. METHODS AND RESULTS: The ability of B. natatoria 2.1 and M. luteus 2.13 to coaggregate with one another was assessed following growth in liquid culture as colonies on agar or within a poloxamer hydrogel matrix. In all these environments a cycle of gain and loss of coaggregation occurred when the two cell types were aged simultaneously, with optimum expression occurring in early stationary phase. Blastomonas natatoria 2.1 cells only coaggregated maximally after entry into stationary phase. Conversely, M. luteus 2.13 cells only coaggregated in exponential phase and early stationary phase and coaggregation ability was lost in late stationary phase. Maximal coaggregation therefore only occurred between the two strains if both were in early stationary phase, when the surface properties of the two cell types were optimal for coaggregation. CONCLUSION: In addition to occurring between cells grown in liquid culture, coaggregation between aquatic bacteria occurs after growth as a biofilm on agar and in an artificial biofilm matrix in poloxamer. Under all conditions, the B. natatoria 2.1 coaggregation adhesin and complementary receptor on M. luteus 2.13 were only expressed simultaneously during early stationary phase.

Agar↗
PubMed2004

Induction of the mar operon by miscellaneous groceries.

AIM: To investigate the potential of non-antibacterial consumer products to act as inducers of the multiple antibiotic resistance (mar) operon of Escherichia coli SPC105. METHODS AND RESULTS: Wells were cut into chemically defined agar medium (CDM) contained within Petri dishes. Molten agar slurries were prepared by mixing known quantities of 35 consumer products with molten CDM and these were pipetted into each well. Plates were overlaid with molten CDM (5 ml), containing 40 microg ml(-1) X-gal and approx. 1000 CFU ml(-1) of an overnight culture of E. coli SPC105 containing a chromosomal marOII::lacZ fusion. After incubation (37 degrees C, 24 h), plates were examined for zones of growth inhibition and the presence of a blue coloration, indicative of mar (marOII::lacZ) induction. Of the 35 products tested (nine herbs and spices, 19 food and drinks and seven household products), 24 (69%) of the items produced inhibitory zones and 22 (63%) of the items induced mar expression. Apple puree was inhibitory but did not induce marOII::lacZ. Mustard, chilli and garlic were shown to be powerful inducers of marOII::lacZ. Overall six products were shown to be powerful marOII::lacZ inducers. None of these made hygiene claims. CONCLUSIONS: In addition to induction by specific biocides and antibiotics, mar is induced by the exposure of bacteria to natural substances, many of which are common to a domiciliary setting. SIGNIFICANCE AND IMPACT OF THE STUDY: Concern that the overuse of antibacterials within consumer products might select for mar-mediated resistance is shortsighted and fails to recognize the ubiquity of inducers in our environment.

Drug Resistance, Multiple, Bacterial↗
PubMed2004

Characterization of nutrient-induced dispersion in Pseudomonas aeruginosa PAO1 biofilm.

The processes associated with early events in biofilm formation have become a major research focus over the past several years. Events associated with dispersion of cells from late stage biofilms have, however, received little attention. We demonstrate here that dispersal of Pseudomonas aeruginosa PAO1 from biofilms is inducible by a sudden increase in carbon substrate availability. Most efficient at inducing dispersal were sudden increases in availability of succinate > glutamate > glucose that led to approximately 80% reductions in surface-associated biofilm biomass. Nutrient-induced biofilm dispersion was associated with increased expression of flagella (fliC) and correspondingly decreased expression of pilus (pilA) genes in dispersed cells. Changes in gene expression associated with dispersion of P. aeruginosa biofilms were studied by using DNA microarray technology. Results corroborated proteomic data that showed gene expression to be markedly different between biofilms and newly dispersed cells. Gene families that were upregulated in dispersed cells included those for flagellar and ribosomal proteins, kinases, and phage PF1. Within the biofilm, genes encoding a number of denitrification pathways and pilus biosynthesis were also upregulated. Interestingly, nutrient-induced dispersion was associated with an increase in the number of Ser/Thr-phosphorylated proteins within the newly dispersed cells, and inhibition of dephosphorylation reduced the extent of nutrient-induced dispersion. This study is the first to demonstrate that dispersal of P. aeruginosa from biofilms can be induced by the addition of simple carbon sources. This study is also the first to demonstrate that dispersal of P. aeruginosa correlates with a specific dispersal phenotype.

Bacterial Proteins↗
PubMed2004

A comparative analysis of abandoned street children and formerly abandoned street children in La Paz, Bolivia.

AIMS AND METHODS: A comparative study of abandoned street children and formerly abandoned street children was conducted in La Paz, Bolivia, representing the first such comparative assessment. Between August and December 1997, all abandoned street children in La Paz, Bolivia, who were willing to participate (n = 124) were interviewed repeatedly at night using standardised questionnaires to collect information on family history, demographics, socioeconomics, drug use, and physical/sexual abuse. The same questionnaires were administered to all former abandoned street children who chose to enter a local orphanage (n = 35). RESULTS: The persistent street children differed greatly from those who entered the orphanage, most markedly in their higher risk of police abuse (95% versus 38%), absence from school (84% versus 19%), engagement in robbery (26% versus 4%), paint thinner use (88% versus 41%), alcohol use (58% versus 12%), and a serious medical problem (53% versus 20%). The risks for street children increased rapidly with age. CONCLUSIONS: A cascade of adverse outcomes afflicts the vast majority of abandoned street children in La Paz, which cumulate with age and diminish the likelihood of successful rehabilitation through lasting placement in an orphanage or residential home. Informed by these findings, the investigators operate a home for abandoned street children in La Paz.

Absenteeism↗