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Biomedical subjects

P Lambert

Publications and source records attributed to P Lambert.

At least 19 recordsLinked to original sources
PubMed2006

Epidemiology, clinical and laboratory characteristics of Staphylococcus aureus bacteraemia in a university hospital in UK.

There has been a persistent increase in the number of meticillin-resistant Staphylococcus aureus (MRSA) and meticillin-susceptible Staphylococcus aureus (MSSA) bacteraemia in the UK. This prospective study included 147 episodes of S. aureus bacteraemia in 139 patients over a 14 month period, from 1 November 2001 to 31 December 2002. Eighty-seven (59%) episodes in 84 patients and 60 (41%) in 56 patients were due to MRSA and MSSA, respectively. An intra-vascular device (29, 33%) and a soft-tissue (15, 25%) source were the commonest identifiable foci for bacteraemia in the MRSA and MSSA groups, respectively. Attributable mortality in the MRSA group was higher than the MSSA group (33% vs 16%; P=0.03) but there was no statistical difference for either attributable (P=0.35) or crude (P=0.39) mortality between the two groups, when adjusted for age, respiratory focus and inappropriate antibiotic therapy. A respiratory source (P=0.02) and inappropriate antibiotic therapy (P=0.02) were associated with attributable mortality in the MRSA group whereas advanced age was the only risk factor (P=0.02) in the MSSA group. The present study shows that S. aureus bacteraemia continues to be a serious infection mostly affecting the elderly and emphasizes the need for improved strategy in the control and management of this condition.

Adolescent↗
PubMed2006

Identification, characterization and quantitation of pyrogenic polycylic aromatic hydrocarbons and other organic compounds in tire fire products.

On 15 August 2001, a tire fire took place at the Pneu Lavoie Facility in Gatineau, Quebec, in which 4000 to 6000 new and recycled tires were stored along with other potentially hazardous materials. Comprehensive gas chromatography-mass spectrometry (GC-MS) analyses were performed on the tire fire samples to facilitate detailed chemical composition characterization of toxic polycyclic aromatic hydrocarbons (PAHs) and other organic compounds in samples. It is found that significant amounts of PAHs, particularly the high-ring-number PAHs, were generated during the fire. In total, 165 PAH compounds including 13 isomers of molecular weight (MW) 302, 10 isomers of MW 278, 10 isomers of MW 276, 7 isomers of MW 252, 7 isomers of MW 228, and 8 isomers of MW 216 PAHs were positively identified in the tire fire wipe samples for the first time. Numerous S-, O-, and N-containing PAH compounds were also detected. The identification and characterization of the PAH isomers was mainly based on: (1) a positive match of mass spectral data of the PAH isomers with the NIST authentic mass spectra database; (2) a positive match of the GC retention indices (I) of PAHs with authentic standards and with those reported in the literature; (3) agreement of the PAH elution order with the NIST (US National Institute of Standards and Technology) Standard Reference Material 1597 for complex mixture of PAHs from coal tar; (4) a positive match of the distribution patterns of PAH isomers in the SIM mode between the tire fire samples and the NIST Standard Reference Materials and well-characterized reference oils. Quantitation of target PAHs was done on the GC-MS in the selected ion monitoring (SIM) mode using the internal standard method. The relative response factors (RRF) for target PAHs were obtained from analyses of authentic PAH standard compounds. Alkylated PAH homologues were quantitated using straight baseline integration of each level of alkylation.

Automobiles↗
PubMed2006

An outbreak of Serratia marcescens on the neonatal unit: a tale of two clones.

Serratia spp. are an important cause of hospital-acquired infections and outbreaks in high-risk settings. Twenty-one patients were infected or colonized over a nine-month period during 2001-2002 on a neonatal unit. Twenty-two isolates collected were examined for antibiotic susceptibility, beta-lactamase production and genotype. Random-amplified polymorphic DNA polymerase chain reaction and pulsed-field gel electrophoresis revealed that two clones were present. The first clone caused invasive clinical infection in four babies, and was subsequently replaced by a non-invasive clone that affected 14 babies. Phenotypically, the two strains also differed in their prodigiosin production; the first strain was non-pigmented whereas the second strain displayed pink-red pigmentation. Clinical features suggested a difference in their pathogenicity. No environmental source was found. The outbreak terminated following enhanced compliance with infection control measures and a change of antibiotic policy. Although S. marcescens continued to be isolated occasionally for another five months of follow-up, these were sporadic isolates with distinct molecular typing patterns.

Clone Cells↗
PubMed2006

Inter-patient variability upon induction with sevoflurane estimated by the time to reach predefined end-points of depth of anaesthesia.

BACKGROUND AND OBJECTIVES: A difficult issue in anaesthesia is its titration for an individual patient to avoid over- and underdosage. Common practice is to use an initial dose and increase it subsequently if the defined end-point is not reached. This assumes that the end-point is reached after a similar interval of time in all patients given a similar dose. In order to test this hypothesis we measured the time to reach end-points such as loss of consciousness (LOC), a bispectral index (BIS) value of 60, the minimal BIS and the minimal mean arterial pressure (MAP) values. METHODS: Thirty patients aged 18-60 yr scheduled for general surgery were included in this observational study. After preoxygenation, induction was performed with 6% inspired concentration of sevoflurane in 6 Lmin-1 oxygen using the SiBI connector and the tidal volume technique. Remifentanil was administered when the BIS value was 60 and tracheal intubation was performed 4 min later. RESULTS: Time (median, minimum-maximum) to LOC, a BIS value of 60, the minimal BIS and MAP values were, respectively, 75 (45-135), 120 (75-270), 300 (120-720) and 450 (120-1200) seconds. The time to the minimal BIS value was significantly (P < 0.05) shorter than the time to reach the minimal MAP value. CONCLUSIONS: These results demonstrate large inter-patient variability for the time necessary to reach defined end-points of depth of anaesthesia when a similar dose of anaesthetic is given. Measuring the time to reach a predefined BIS value would allow application of nociceptive stimuli only at adequate levels of hypnosis and would facilitate titration.

Adolescent↗
PubMed2006

Infection risk associated with a closed luer access device.

The potential for microbial contamination associated with a recently developed needleless closed luer access device (CLAD) (Q-Syte; Becton Dickinson, Sandy, UT, USA) was evaluated in vitro. Compression seals of 50 multiply activated Q-Syte devices were inoculated with Staphylococcus epidermidis NCTC 9865 in 25% (v/v) human blood and then disinfected with 70% (v/v) isopropyl alcohol followed by flushing with 0.9% (w/v) sterile saline. Forty-eight of 50 (96%) saline flushes passed through devices that had been activated up to a maximum of 70 times remained sterile. A further 25 Q-Syte CLADs that had undergone multiple activations were challenged with prefilled 0.9% (w/v) sterile saline syringes, the external luer tips of which had been inoculated with S. epidermidis NCTC 9865 prior to accessing the devices. None of the devices that had been accessed up to 70 times allowed passage of micro-organisms, despite challenge micro-organisms being detected on both the syringe tip after activation and the compression seals before decontamination. These findings suggest that the Q-Syte CLAD may be activated up to 70 times with no increased risk of microbial contamination within the fluid pathway. The device may also offer protection from the external surface of syringe tips contaminated with micro-organisms.

2-Propanol↗
PubMed2005

Evaluation of a 2% chlorhexidine gluconate in 70% isopropyl alcohol skin disinfectant.

The efficacy of a new skin disinfectant, 2% (w/v) chlorhexidine gluconate (CHG) in 70% (v/v) isopropyl alcohol (IPA) (ChloraPrep), was compared with five commonly used skin disinfectants against Staphylococcus epidermidis RP62A in the presence or absence of protein, utilizing quantitative time-kill suspension and carrier tests. All six disinfectants [70% (v/v) IPA, 0.5% (w/v) aqueous CHG, 2% (w/v) aqueous CHG, 0.5% (w/v) CHG in 70% (v/v) IPA and 10% (w/v) aqueous povidone iodine (PI)] achieved a log(10) reduction factor of 5, in colony-forming units/mL, in a suspension test (exposure time 30s) in the presence and absence of 10% human serum. Subsequent challenges of S. epidermidis RP62A in a biofilm (with and without human serum) demonstrated reduced bactericidal activity. Overall, the most effective skin disinfectants tested against S. epidermidis RP62A were 2% (w/v) CHG in 70% IPA and 10% (w/v) PI. These results suggest that enhanced skin antisepsis may be achieved with 2% (w/v) CHG in 70% (v/v) IPA compared with the three commonly used CHG preparations [0.5% (w/v) aqueous CHG, 2% (w/v) aqueous CHG and 0.5% (w/v) CHG in 70% (v/v) IPA].

2-Propanol↗
PubMed2005

Analogues of virus resistance genes map to QTLs for resistance to sharka disease in Prunus davidiana.

Plum pox virus (PPV), the causative agent of sharka disease in Prunoideae, is one of the most serious problems affecting stone fruit production in Europe and America. Resistance to PPV was previously described in a Prunus davidiana clone, P1908, and introduced into peach (Prunus persica) genotypes. Genetic resistance to PPV displays a complex pattern of quantitative inheritance. An analysis of quantitative trait loci (QTLs) for resistance was performed on an F1 interspecific peach population obtained from a cross between the susceptible nectarine cultivar Summergrand and P. davidiana. The hybrids were graft-inoculated with PPV in duplicate following a classical procedure. The incidence of infection was evaluated four times, over two vegetative cycles, by symptom observation and enzyme-linked immunoadsorbent assays (ELISA). Restriction of systemic downward movement of the PPV virus was also evaluated by testing the susceptible rootstocks. Using both analysis of variance and non-parametric tests, six genomic regions involved in PPV resistance were detected. Depending on the scoring data considered, between 22 and 51% of the phenotypic variance could be explained by the quantitative model. One QTL, located in the distal region of linkage group 1, maps in a genomic region that is syntenic to the location of a resistance gene previously identified in the apricot cv. Goldrich. Some QTLs appeared to be temporally specific, reflecting the environmental dependence of PPV-resistance scoring. Candidate gene fragments were amplified by PCR, isolated and mapped on the peach interspecific linkage map. We report here the co-localization of three analogues of virus resistance genes with two distinct genomic regions linked to PPV resistance in P. davidiana.

Base Sequence↗
PubMed2005

Effects of oligofructose on glucose and lipid metabolism in patients with nonalcoholic steatohepatitis: results of a pilot study.

OBJECTIVE: In experimental animals, recent results suggest that the addition of inulin-type fructans such as oligofructose (OFS) in the diet decreases triacylglycerol accumulation in the liver tissue. Therefore, we have investigated the effect of daily ingestion of OFS in seven patients with nonalcoholic steatohepatitis (NASH), confirmed by liver biopsies. DESIGN: They received 16 g/day OFS or maltodextrine (placebo) for 8 weeks in a randomized double-blind crossover design. Energy intake, body composition, liver steatosis and blood parameters were analysed after 4 and 8 weeks of dietary supplementation. RESULTS: Compared to placebo, OFS decreased significantly serum aminotransferases, aspartate aminotransferase after 8 weeks, and insulin level after 4 weeks, but this could not be related to significant effect on plasma lipids. CONCLUSION: This pilot study supports the putative interest of OFS in the management of liver diseases associated with abnormal lipid accumulation in humans.

Adult↗
PubMed2004

Surprising sun: a new step towards a complete picture?

Important revisions of the solar model ingredients have appeared recently. We first show that the updated CNO composition suppresses the anomalous position of the Sun in the known galactic enrichment. The following law, He/H = 0.075 + 44.6 O/H in number fraction, is now compatible with all the indicators. We then suggest some directions of investigation to solve the discrepancies between the standard model and solar seismic observations. We finally update our predicted neutrino fluxes using a seismic model and all the recent progress. We get 5.31 +/- 0.6 x 10(6)/cm2/s for the total 8B neutrinos, 66.5 +/- 4.4 SNU and 2.76 +/- 0.4 SNU for the gallium and chlorine detectors, all in remarkable agreement with the detected values including neutrino oscillations for the last two. So, the acoustic modes and detected neutrinos see the same Sun, but the standard model fails to reproduce them.

Journal Article↗
PubMed2004

Characterization and identification of the Detroit River mystery oil spill (2002).

In this paper, a case study of the Detroit River mystery oil spill (2002) is presented that demonstrates the utility of detailed and integrated oil fingerprinting in investigating unknown or suspected oil spills. The detailed diagnostic oil fingerprinting techniques include determination of hydrocarbon groups and semi-quantitative product screening, analysis of oil-characteristic biomarkers and the extended suite of parent and alkylated polycyclic aromatic hydrocarbons (PAHs), and quantitative determination of a variety of diagnostic ratios of "source-specific marker" compounds. The detailed chemical fingerprinting data and results highlight the followings: (1) The spill samples were largely composed of used lube oil mixed with smaller portion of diesel fuel. (2) The diesel in the samples had been weathered and degraded. (3) Sample 3 collected from N. Boblo Island on 14 April was more weathered (most probably caused by more evaporation and water-washing) than samples 1 and 2. (4) All fingerprinting results clearly demonstrated oils in three samples were the same, and they came from the same source. (5) Most PAH compounds were from the diesel portion in the spill samples, while the biomarker compounds were largely from the lube oil. (6) Input of pyrogenic PAHs to the spill samples was clearly demonstrated. The pyrogenic PAHs were most probably produced from combustion and motor lubrication processes, and the lube oil in these spill samples was waste lube oil.

Michigan↗
PubMed2004

Hypoxaemia after cardiac surgery: clinical application of a model of pulmonary gas exchange.

BACKGROUND AND OBJECTIVE: To investigate the clinical application of a mathematical model of pulmonary gas exchange, which ascribes hypoxaemia to shunt and ventilation/perfusion mismatch. Ventilation/perfusion mismatch is quantified by deltaPO2, which is the drop in oxygen pressure from alveoli to lung capillaries. Shunt and deltaPO2 were used to describe changes in oxygenation after coronary artery bypass grafting. METHODS: Fourteen patients were studied 2-4 h after surgery and on postoperative days 2, 3 and 7. On each occasion inspired oxygen fraction was changed in four to six steps to obtain arterial oxygen saturation (SaO2) in the range of 90-100%, enabling construction of FEO2/SaO2 curves. Measurements of ventilation, circulation and oxygenation were entered in a previously described mathematical model of pulmonary gas exchange. RESULTS: We found that oxygenation was most impaired 3 days after surgery. By fitting the mathematical model to the FEO2/SaO2 curve, we found that shunt remained constant throughout the study period. However, deltaPO2 increased from 0.5 kPa (median, range 0-3.8) 2-4 h after surgery, to 3.2 kPa (range 1.2-6.4, P < 0.05) on day 2, and to 4.0 kPa (range 1.2-8.3) on day 3. On day 7, deltaPO2 decreased to 2.2 kPa (range 0-3.5, P < 0.05). CONCLUSIONS: Ventilation/perfusion mismatch (deltaPO2), rather than shunt, explains the changes in postoperative oxygenation. The model of pulmonary gas exchange may serve as a useful and potentially non-invasive clinical tool for monitoring patients at risk of postoperative hypoxaemia.

Aged↗
PubMed2003

Genetic linkage maps of two apricot cultivars ( Prunus armeniaca L.) compared with the almond Texas x peach Earlygold reference map for Prunus.

Several genetic linkage maps have been published in recent years on different Prunus species suggesting a high level of resemblance among the genomes of these species. One of these maps (Joobeur et al., Theor Appl Genet 97:1034-1041 [(1998); Aranzana et al., Theor Appl Genet 106:819-825 (2002b)] constructed from interspecific almond Texas x peach Earlygold F(2) progeny (TxE) was considered to be saturated. We selected 142 F(1) apricot hybrids obtained from a cross between P. armeniaca cvs. Polonais and Stark Early Orange for mapping. Eighty-eight RFLP probes and 20 peach SSR primer pairs used for the 'reference map' were selected to cover the eight linkage groups. One P. davidiana and an additional 14 apricot simple sequence repeats (SSRs) were mapped for the F(1) progeny. Eighty-three amplified fragment length polymorphisms were added in order to increase the density of the maps. Separate maps were made for each parent according to the 'double pseudo-testcross' model of analysis. A total of 141 markers were placed on the map of Stark Early Orange, defining a total length of 699 cM, and 110 markers were placed on the map of Polonais, defining a total length of 538 cM. Twenty-one SSRs and 18 restriction placed in the TxE map were heterozygous in both parents (anchor loci), thereby enabling the alignment of the eight homologous linkage groups of each map. Except for 15 markers, most markers present in each linkage group in apricot were aligned with those in TxE map, indicating a high degree of colinearity between the apricot genome and the peach and almond genomes. These results suggest a strong homology of the genomes between these species and probably between Prunophora and Amygdalus sub-genera.

Chromosome Mapping↗
PubMed2003

A literature review of portable fluorescence-based oil-in-water monitors.

The results of a literature search on fluorescence-based portable detectors to measure the real-time concentration of oil are reported. For more than two decades, fluorometers have been commonly employed to monitor dispersed oil levels at oil spills on water. The focus of this paper has been to extract specific information from references about how the instruments were used, including set up and calibration procedures, the oil and dispersant measured, the approximate concentration range of the oil in the water column, and how the real-time data compared to traditional laboratory techniques.

Accidents↗
PubMed2003

Field fluorometers as dispersed oil-in-water monitors.

A laboratory study of the Turner Instrument flow-through models 10AU and 10 fluorometers was conducted to review their ability to measure real-time oil-in-water concentrations, to compare the results to other total petroleum hydrocarbon (TPH) procedures and to improve the understanding of the relationship of the fluorescence to the chemical composition of the oils. Comparison of the fluorometer results to standard infrared and gas chromatography laboratory procedures showed all methods capable of detecting and differentiating between small changes in oil concentration. The infrared and gas chromatography generated similar values while the fluorometer values were of the same order of magnitude but typically 20-80% higher. The chemical composition of the oils was determined by gas chromatographic techniques and compared to the signal outputs of the fluorometers. It was found that the fluorometer data could not be directly linked to the concentration of any specific aromatic hydrocarbon such as naphthalene or to the sum of the polycyclic aromatic hydrocarbon (PAH) compounds. Evidence suggests that the fluorescence signal is generated by a combination of PAH compounds. Also, the response of the fluorometers may also be influenced by the presence of volatile aromatic compounds such as benzene, toluene, ethyl benzene and xylene (BTEX) and C3-benzenes (BTEX + C3B) in combination with the PAH compounds.

Chromatography, Gas↗
PubMed2002

Carbapenem-resistant Acinetobacter and role of curtains in an outbreak in intensive care units.

Multiple-antibiotic-resistant Acinetobacter baumanii, including meropenem resistance, was first isolated from a patient in the general intensive care unit of a tertiary-referral university teaching hospital in Birmingham in December 1998. Similar strains were subsequently isolated from 12 other patients, including those on another intensive care unit within the hospital. The outbreak followed an increase in the use of meropenem in both the units. Environmental screening revealed the presence of the multiple-resistant Acinetobacter species on fomite surfaces in the intensive care unit and bed linen. The major source appeared to be the curtains surrounding patients' beds. Typing by pulsed field gel electrophoresis demonstrated that the patients' isolates and those from the environment were indistinguishable. Rigorous infection control measures including increased frequency of cleaning of the environment with hypochlorite (1000 ppm) and twice-weekly changing of curtains were implemented, along with restriction of meropenem use in the units. Isolation of the multiple-resistant Acinetobacter spp. subsequently diminished and it was not detected over a follow-up period of 18 months. To our knowledge, this is the first reported outbreak of carbapenem-resistant Acinetobacter spp. from the UK. This outbreak also highlights environmental sources, particularly dry fabrics such as curtains, as an important reservoir for dissemination of acinetobacters.

Acinetobacter↗
PubMed2001

Tolerance or immunity to a tumor antigen expressed in somatic cells can be determined by systemic proinflammatory signals at the time of first antigen exposure.

Mice transgenic for the E7 tumor Ag of human papillomavirus type 16, driven from a keratin 14 promoter, express E7 in keratinocytes but not dendritic cells. Grafted E7-transgenic skin is not rejected by E7-immunized mice that reject E7-transduced transplantable tumors. Rejection of recently transplanted E7-transgenic skin grafts, but not of control nontransgenic grafts or of established E7-transgenic grafts, is induced by systemic administration of live or killed Listeria monocytogenes or of endotoxin. Graft recipients that reject an E7 graft reject a subsequent E7 graft more rapidly and without further L. monocytogenes exposure, whereas recipients of an E7 graft given without L. monocytogenes do not reject a second graft, even if given with L. monocytogenes. Thus, cross-presentation of E7 from keratinocytes to the adaptive immune system occurs with or without a proinflammatory stimulus, but proinflammatory stimuli at the time of first cross-presentation of Ag can determine the nature of the immune response to the Ag. Furthermore, immune effector mechanisms responsible for rejection of epithelium expressing a tumor Ag in keratinocytes are different from those that reject an E7-expressing transplantable tumor. These observations have implications for immunotherapy for epithelial cancers.

Animals↗
PubMed2001

Enhancement of the p300 HAT activity by HIV-1 Tat on chromatin DNA.

HIV-1 Tat is able to form a ternary complex with P/CAF and p300 and increase the affinity for CDK9/P-TEFb CTD kinase complex. Our previous study demonstrated that Tat binds to p300/CBP in the minimal HAT domain (aa 1253-1790) and that the interaction results in a change of conformation on p300/CBP. Here, we show that the Tat-p300 interaction increases the HAT activity of p300 on histone H4 that is associated with nucleosomal DNA and not with free histones. Nucleosomal histone H4 was acetylated on lysines 8, 12, and 16. Acetylation of H4 was inhibited by Lys-coenzyme A (CoA), a selective inhibitor of p300 acetyltransferase activity. Unexpectedly, we also found that Tat could autoacetylate itself, which was specific to lysine residues 41 and 71. Peptides lacking these two lysines could not enhance the HAT activity of p300. Comparison of the sequences of Tat with other HIV-1 clades and HAT containing transcription factors indicated sequence identity in the acetyl-CoA binding motif A, KGXG. Furthermore, when utilizing an in vitro transcription assay, as well as a Tat mutant virus, we found that ectopic expression of only wild-type Tat in the presence of p300, and not a lysine 41 Tat mutant, could activate HIV-1 chromatin DNA, as evidenced by the absence of HIV-1 virion antigen. Therefore, transcription of integrated viral DNA in vivo requires the HAT activity of coactivators that are modulated by Tat to derepress the HIV-1 chromatin structure and aid in activated transcription.

Acetyl-CoA C-Acetyltransferase↗