Search PubMed⌕ Search

Biomedical subjects

P Rice

Publications and source records attributed to P Rice.

At least 19 recordsLinked to original sources

Rapid screening of H(2)O(2) production by Mycoplasma mycoides and differentiation of European subsp. mycoides SC (small colony) isolates.

Mycoplasma mycoides strains were screened for the ability to produce H(2)O(2) from glucose and glycerol metabolism using rapid and simple colorimetric assays. In quantitative assays, H(2)O(2) production by washed cell suspensions was detected by the oxidation of o-dianisidine in the presence of peroxidase. In qualitative assays, a 3,3'-diaminobenzidine-peroxidase reagent was applied to colonies on agar plates. Both methods enabled differentiation of European subsp. mycoides SC (small colony) isolates from other M. mycoides strains by their inability to produce H(2)O(2) from glycerol metabolism. In addition, two strains of subsp. capri were identified which produced large amounts of H(2)O(2) from glucose oxidation. In lysed cells of these strains, NADH oxidation gave approximately 1 mol H(2)O(2) per mol NADH oxidised whereas in 36 subsp. mycoides and 10 other subsp. capri strains, the quantity produced was 0.01-0.20mol H(2)O(2) per mol NADH oxidised.

Colorimetry↗

A (1-->3)-beta-D-linked heptasaccharide is the unit ligand for glucan pattern recognition receptors on human monocytes.

Glucans are fungal cell wall polysaccharides which stimulate innate immune responses. We determined the minimum unit ligand that would bind to glucan receptors on human U937 cells using laminarin-derived pentaose, hexaose, and heptaose glucan polymers. When U937 membranes were pretreated with the oligosaccharides and passed over a glucan surface, only the heptasaccharide inhibited the interaction of glucan with membrane receptors at a K(d) of 31 microM (95% CI 20-48 microM) and 100% inhibition. However, the glucan heptasaccharide did not stimulate U937 monocyte NFkappaB signaling, nor did it increase survival in a murine model of polymicrobial sepsis. Laminarin, a larger and more complex glucan polymer (M(w) = 7700 g/mol), only partially inhibited binding (61 +/- 4%) at a K(d) of 2.6 microM (99% CI 1.7-4.2 microM) with characteristics of a single binding site. These results indicate that a heptasaccharide is the smallest unit ligand recognized by macrophage glucan receptors. The data also indicate the presence of at least two glucan-binding sites on U937 cells and that the binding sites on human monocyte/macrophages can discriminate between glucan polymers. The heptasaccharide and laminarin were receptor antagonists, but they were not receptor agonists with respect to activation of NFkappaB-dependent signaling pathways or protection against experimental sepsis.

Animals↗

Resistance-associated mutations in the human immunodeficiency virus type 1 subtype c protease gene from treated and untreated patients in the United Kingdom.

This work reports the variability of human immunodeficiency virus type 1 (HIV-1) protease from treated and untreated patients infected with HIV-1 subtype C in the United Kingdom. The most common primary mutation observed in treated patients was L90M. D30N, M46I, V82A/F, and I84V were seen rarely. M36I and I93L mutations were observed in nearly all samples from both treated and untreated patients and so cannot be considered as resistance-associated mutations in this subtype.

Diseases in Twins↗

The effect of hexafluorocyclobutene on rat bronchoalveolar lavage fluid surfactant phospholipids and alveolar type II cells.

Hexafluorocyclobutene (HFCB), a reactive organohalogen gas, causes overwhelming pulmonary oedema. We investigated its effect on the rat lung surfactant system, comparing its action on type II pneumocytes with air-exposed rats. The inflammatory cell population and protein content of bronchoalveolar lavage fluid was analysed following exposure to air or HFCB (LCt30). Six rat lung phospholipids were measured by high-performance liquid chromatography, following solid phase extraction (SPE) from lavage fluid. Transmission electron microscopy (TEM) was used to visualise effects on alveolar type II cell ultrastructure. HFCB caused changes in cell populations and increased lavage fluid protein compared to controls, suggesting a permeability oedema. Changes in the total amount and percentage composition (sustained decrease in phosphatidylglycerol and phosphatidylcholine) of surfactant phospholipids also occurred. TEM observations indicated no direct ultrastructural damage to the type II cells, but showed initial, rapid release of surfactant into the alveolar space. HFCB altered the surfactant system in a manner similar to that shown following another reactive organohalogen gas, perfluoroisobutene (PFIB), but differently to that after phosgene. These differences suggest different mechanisms of action even though pulmonary oedema is the final injury for all gases. Better knowledge of the mechanisms involved will improve prospects for prophylactic/therapeutic intervention.

Animals↗

Growth inhibition in G(1) and altered expression of cyclin D1 and p27(kip-1 )after forced connexin expression in lung and liver carcinoma cells.

Gap junctional intercellular communication (GJIC) and connexin expression are frequently decreased in neoplasia and may contribute to defective growth control and loss of differentiated functions. GJIC, in E9 mouse lung carcinoma cells and WB-aB1 neoplastic rat liver epithelial cells, was elevated by forced expression of the gap junction proteins, connexin43 (Cx43) and connexin32 (Cx32), respectively. Transfection of Cx43 into E9 cells increased fluorescent dye-coupling in the transfected clones, E9-2 and E9-3, to levels comparable to the nontransformed sibling cell line, E10, from which E9 cells originated. Transduction of Cx32 into WB-aB1 cells also increased dye-coupling in the clone, WB-a/32-10, to a level that was comparable to the nontransformed sibling cell line, WB-F344. The cell cycle distribution was also affected as a result of forced connexin expression. The percentage of cells in G(1)-phase increased and the percentage in S-phase decreased in E9-2 and WB-a/32-10 cells as compared to E9 and WB-aB1 cells. Concomitantly, these cells exhibited changes in G(1)-phase cell cycle regulators. E9-2 and WB-a/32-10 cells expressed significantly less cyclin D1 and more p27(kip-1) protein than E9 and WB-aB1 cells. Other growth-related properties (expression of platelet-derived growth factor receptor-beta, epidermal growth factor receptor, protein kinase C-alpha, protein kinase A regulatory subunit-Ialpha, and production of nitric oxide in response to a cocktail of pro-inflammatory cytokines) were minimally altered or unaffected. Thus, enhancement of connexin expression and GJIC in neoplastic mouse lung and rat liver epithelial cells restored G(1) growth control. This was associated with decreased expression of cyclin D1 and increased expression of p27(kip-1), but not with changes in other growth-related functions.

Animals↗

Dermabrasion--a novel concept in the surgical management of sulphur mustard injuries.

Since its first use on the battlefields of Northern France during the First World War (1914-1918), sulphur mustard has remained a significant chemical threat to military forces around the world. Progress towards an effective treatment for these injuries has been slow due to the lack of suitable animal models upon which to study the toxicology and pathology. However, porcine and human skin are similar in structure and exposures to sulphur mustard vapour have been performed on porcine models to define the development and subsequent resolution of mustard-induced skin injuries. Yucatan miniature (n = 12) and large white (n = 6) pig models were used to assess the usefulness of mechanical dermabrasion in accelerating the naturally slow rate of healing of sulphur mustard vapour-induced injuries to the skin. Burn injuries underwent debridement at 4 days post-exposure and the resulting lesions were assessed at various time points up to 8 weeks post-abrasion. Rates of re-epithelialisation were accelerated in the dermabrasion (treated) vs the control (untreated) group by up to a factor of three (ANOVA: p = .0196, Yucatan; p = 0.165, large white pig). It was concluded that dermabrasion of sulphur mustard burns is a valuable procedure in the surgical management of these injuries.

Animals↗

Non-invasive quantification of skin injury resulting from exposure to sulphur mustard and Lewisite vapours.

The severity and progression of skin lesions resulting from exposure to the chemical warfare agents Lewisite (L) and sulphur mustard (SM) have been investigated using the non-invasive biophysical methods of evaporimetry and reflectance spectroscopy in large white pigs in vivo. Erythema (redness) expressed immediately after exposure to L or SM vapours appeared to be related to the lesion severity as demonstrated by histopathological analysis. Skin brightness correlated well with scab formation whereas blueness (cyanosis) did not appreciably alter throughout the study. Rates of transepidermal water loss (TEWL) changed both with occlusion (during vapour exposure) and also mirrored the progression of macroscopic skin injury after 12 h. Whilst no single parameter could be used in isolation to ascertain the severity and subsequent progression of the skin lesions, measurement of erythema, skin brightness and TEWL could provide quantitative, non-invasive methods for determining the efficacy of antidotes or therapies to prevent the toxic effects of chemical warfare agents. However, neither colourimetry or TEWL provided a clinical evaluation of such lesions that were comparable with the prognostic capabilities of laser Doppler imaging.

Animals↗

A rapid biochemical test to aid identification of Mycoplasma mycoides subsp. mycoides small colony (SC) strains.

The ability to utilize maltose, as determined by measurement of oxygen uptake, is used to differentiate Mycoplasma mycoides subsp. mycoides small colony (SC) and M. capricolum subsp. capripneumoniae (all strains negative) from other members of the M. mycoides cluster (M. mycoides subsp. capri, M. mycoides subsp. mycoides large colony (LC), M. capricolum subsp. capricolum; and bovine serogroup 7; 94% of strains positive). Rapid tests for maltose utilizing ability were developed, based on hydrolysis of a chromogenic alpha-glucosidase (maltase) substrate (p-nitrophenyl-alpha-D-glucopyranoside, colourless) to give a brightly coloured product (p-nitrophenol, yellow). On agar plates, colonies of maltose-utilizing strains became coloured within 40 min.

Animals↗

Artemis: sequence visualization and annotation.

SUMMARY: Artemis is a DNA sequence visualization and annotation tool that allows the results of any analysis or sets of analyses to be viewed in the context of the sequence and its six-frame translation. Artemis is especially useful in analysing the compact genomes of bacteria, archaea and lower eukaryotes, and will cope with sequences of any size from small genes to whole genomes. It is implemented in Java, and can be run on any suitable platform. Sequences and annotation can be read and written directly in EMBL, GenBank and GFF format. AVAILABITLTY: Artemis is available under the GNU General Public License from http://www.sanger.ac.uk/Software/Artemis

Databases, Factual↗

Recurrence of hepatitis B after single lung transplantation.

This study describes a patient who developed decompensated liver disease secondary to reactivation of hepatitis B infection 20 months after single lung transplantation following augmentation of immunosuppression to treat allograft rejection. Discussion focuses on the virologic and management issues of this case and reviews the approach taken when considering patients with chronic hepatitis B infection for lung transplantation.

Adult↗

The development of Lewisite vapour induced lesions in the domestic, white pig.

Studies performed in the past in our laboratory have detailed the development of sulphur mustard lesions in the domestic, white pig using small glass chambers to achieve saturated vapour exposure under occluded conditions. We have now used this experimental model to produce cutaneous lesions for detailed histopathological studies following challenge with lewisite. Histological examination of resulting lesions have revealed that although the overall pattern of lesion development is similar to that seen following mustard challenge, the time-course of cellular events is very much compressed. The epidermis showed focal basal cell vacuolation with associated acute inflammation as early as one hour postexposure. Coagulative necrosis of the epidermis and papillary dermis was complete by 24 hours and followed the appearance of multiple coalescent blisters between six and 12 hours post-exposure. At 48 hours, the lesions were full thickness burns with necrosis extending into the deep subcutaneous connective and adipose tissues. The study of lesions beyond 24 hours revealed early epithelial regeneration at the wound edge. The overall spontaneous healing rate of these biologically severe lesions was significantly faster than comparable sulphur mustard injuries and probably reflected a lack of alkylation of DNA and RNA.

Animals↗

Effect of alcohol on the oral mucosa assessed by quantitative cytomorphometry.

The effect of alcohol on the oral mucosa was assessed using quantitative cytomorphology applied to smears taken from clinically normal oral mucosa of patients attending an alcohol problem unit and results were compared to a control group (consisting of social and non-drinkers) attending a hospital for routine dental care. Smears were stained using the Papanicolaou method and the nuclear and cell boundaries of 50 randomly selected cells traced and mean areas (NA and CA, respectively) calculated. The average number of units of alcohol consumed were recorded for each group together with relevant blood tests. The alcohol group was further subdivided into "binge" and "regular" drinkers. No significant differences were found between mean NA and mean CA values for these two types of alcohol drinkers, despite a marked difference in weekly units consumed. However, a statistically significant reduction in mean cytoplasmic area (P < 0.001) and mean nuclear area (P < 0.01) was found for the alcohol group when compared to controls. In conclusion, excess alcohol intake may influence results for quantitative oral cytomorphology. Further research is indicated on the relative effects of alcohol (both topical and systemic).

Adult↗

The effect of perfluoroisobutene and phosgene on rat lavage fluid surfactant phospholipids.

1. This study investigated whether the reactive organohalogen gases perfluoroisobutene (PFIB) and phosgene, which cause death by overwhelming pulmonary oedema, affect the surfactant system or type II pneumocytes of rat lung. 2. The progression and type of pulmonary injury in Porton Wistar-derived rats was monitored over a 48 h period following exposure to either PFIB or phosgene (LCt30) by analyzing the inflammatory cells and protein in bronchoalveolar lavage fluid. Six rat lung phospholipids were measured by high-performance liquid chromatography, following solid phase extraction from lavage fluid. 3. Alterations in the cell population and lung permeability occurred following both gases, indicating that the injury was a permeability-type pulmonary oedema. Changes in the total amount of phospholipid and in the percentage composition of the surfactant were different for the two gases. PFIB produced increases in phosphatidylglycerol and phosphatidylcholine over the first hour, similar to that seen following air exposure, followed by substantial decreases in these phospholipids. Phosgene caused late increases in all phospholipids from 6 h post-exposure. 4. Differences in the response of the surfactant system to exposure to PFIB and phosgene suggest different mechanisms of action at the alveolar surface although the final injurious response is pulmonary oedema for both gases.

Administration, Inhalation↗

Early experience using duplex ultrasonography in the diagnosis of deep venous thrombosis; a prospective evaluation.

Duplex ultrasound is used in many radiology departments as the first line of investigation for symptomatic deep venous thrombosis. Before changing the practice of our department from venography to duplex ultrasonography, we wanted to assess our ability to identify deep venous thrombosis on ultrasound. Thirty-eight patients were investigated for suspected deep venous thrombosis by venography and duplex ultrasound. The results were compared using venography as the 'gold standard'. Duplex ultrasound correctly identified 13 out of 16 limbs with deep venous thrombosis. Four of the 38 duplex ultrasound examinations (11%) were described as inadequate at the time of examination, and when these are excluded from the analysis a sensitivity of 93 %, and specificity of 80 % are achieved. We conclude that there is a significant learning curve when performing duplex ultrasound of the lower limb, and that change-over from venography to ultrasound should include a period during which both examinations are routinely performed.

Adult↗

Diminished CYP2E1 expression and formation of 2-S-glutathionyl acetate, a glutathione conjugate derived from 1,1-dichloroethylene epoxide, in murine lung tumors.

We hypothesized that resistance of lung tumors to the cytotoxic effects of xenobiotics is associated with loss of cytochrome P-450 expression, leading to defective formation of reactive intermediates. To test this hypothesis, we investigated 1,1-dichloroethylene (DCE), a chemical that causes Clara cell damage, in a urethane-induced model of lung tumorigenesis. Lung metabolism of DCE yields 2-S-glutathionyl acetate (conjugate [C]), a glutathione conjugate derived from DCE-epoxide, believed to be the ultimate toxic species. We used immunohistochemistry to investigate CYP2E1 expression in nontumor- and tumor-bearing lung to identify cells capable of generating [C]. CYP2E1 and [C] were colocalized in adjacent tissue sections to determine coincidence between CYP2E1 and [C] in lung cells. CYP2E1 was highly localized to the bronchiolar epithelium of nontumor-bearing lung and in uninvolved tissue of tumor-bearing lung and was concentrated in the Clara cells. In contrast, tumor foci including hyperplasias, adenomas, and carcinomas were deficient in CYP2E1 in both untreated and DCE-treated mice. Immunoreactivity for [C] was also detected in the bronchiolar epithelium in nontumor-bearing lung and uninvolved tissue of tumor-bearing lung of DCE-treated mice and was reduced in hyperplasias, adenomas, or carcinomas. Thus, there was a coincidence between the sites of CYP2E1 expression and [C] formation. Conjugate [C] accumulated only in lung cells in which CYP2E1 was expressed. Histochemical staining for glutathione confirmed its presence in tumor foci. Thus, bioactivation and conjugation of DCE occur in structurally normal tissue from both nontumor- and tumor-bearing lung but was lost in tumor tissue, irrespective of the stage of tumor development.

Adenoma↗

Ligand binding to the (1 --> 3)-beta-D-glucan receptor stimulates NFkappaB activation, but not apoptosis in U937 cells.

Recent data suggest that sepsis stimulates macrophage apoptosis (Ao) with subsequent induction of macrophage dysfunction. Nuclear factor-kappaB (NFkappaB) activation has been linked to Ao in either a pro- or antiapoptotic role. Glucans are biological response modifiers which exert antisepsis activity. This investigation examined the effect of (1-3)-beta-D-glucan receptor binding by a high affinity ligand on Ao and NFkappaB activation in U937 cells in the presence or absence of LPS. A high affinity glucan ligand (IC50 = 23 nM) activated NFkappaB, but did not induce Ao or significantly alter LPS induced U937 Ao. These data indicate that: i) modulation of the macrophage (1-3)-beta-D-glucan receptor stimulates NFkappaB; ii) does not induce Ao or significantly diminish LPS induced Ao and iii) activation of the U937 FAS receptor does not alter the relative Ao responses in glucan and LPS treated cells.

Antibodies↗