Comparison of specific methane yield of perennial ryegrass prepared by thermal drying versus non-thermal drying in small-scale batch digestion tests

Dried milled biomass samples are frequently utilised in small-scale batch digestion tests. However, herbage chemical composition can be altered by thermal drying, and this may affect specific methane (CH4) yields. Thus, the specific CH4 yield of herbage pre- and post-ensiling, prepared by two preparation methods were compared. Perennial ryegrass samples were either non-thermally dried (i.e. subject to cryogenic conditions, -196 °C) or thermally dried (40 °C), prior to milling. Specific CH4 yield was subsequently determined in a small-scale batch digestion test. Herbage pre-ensiling yielded 204 and 243 L CH4 kg(-1)VS(added) and herbage post-ensiling yielded 212 and 188 L CH4 kg(-1)VS(added) with non-thermal dried and thermal dried sample preparation methods, respectively. Due to opposing effects of thermal drying on CH4 yields of herbage either pre- or post-ensiling, it is not recommended to use thermal drying. Instead, it is recommended that non-thermal dried herbage samples are used in small-scale batch digestion tests.

Changes in chemical composition and digestibility of three maize stover components digested by white-rot fungi

Maize stover (total stem and leaves) is not considered a ruminant feed of high nutritive value. Therefore, an improvement in its digestibility may increase the viability of total forage maize production systems in marginal growth regions. The objective of this study was to describe the changes in chemical composition during the storage of contrasting components of maize stover (leaf, upper stem and lower stem) treated with either of two lignin degrading white-rot fungi (WRF; Pleurotus ostreatus, Trametes versicolor). Three components of maize stover (leaf, upper stem and lower stem), harvested at a conventional maturity for silage production, were digested with either of two WRF for one of four digestion durations (1-4 months). Samples taken prior to fungal inoculation were used to benchmark the changes that occurred. The degradation of acid detergent lignin was observed in all sample types digested with P. ostreatus; however, the loss of digestible substrate in all samples inoculated with P. ostreatus was high, and therefore, P. ostreatus-digested samples had a lower dry matter digestibility than samples prior to inoculation. Similarly, T. veriscolor-digested leaf underwent a non-selective degradation of the rumen-digestible components of fibre. The changes in chemical composition of leaf, upper stem and lower stem digested with either P. ostreatus or T. veriscolor were not beneficial to the feed value of the forage, and incurred high DM losses.

The effect of dietary concentrate and soya oil inclusion on microbial diversity in the rumen of cattle

AIMS

Methane emissions from ruminants are a significant contributor to global greenhouse gas production. The aim of this study was to examine the effect of diet on microbial communities in the rumen of steers.

METHODS AND RESULTS

The effects of dietary alteration (50 : 50 vs 90 : 10 concentrate-forage ratio, and inclusion of soya oil) on methanogenic and bacterial communities in the rumen of steers were examined using molecular fingerprinting techniques (T-RFLP and automated ribosomal intergenic spacer analysis) and real-time PCR. Bacterial diversity was greatly affected by diet, whereas methanogen diversity was not. However, methanogen abundance was significantly reduced (P = 0.009) in high concentrate-forage diets and in the presence of soya oil (6%). In a parallel study, reduced methane emissions were observed with these diets.

CONCLUSIONS

The greater effect of dietary alteration on bacterial community in the rumen compared with the methanogen community may reflect the impact of substrate availability on the rumen bacterial community. This resulted in altered rumen volatile fatty acid profiles and had a downstream effect on methanogen abundance, but not diversity.

SIGNIFICANCE AND IMPACT OF THE STUDY

Understanding how rumen microbial communities contribute to methane production and how these microbes are influenced by diet is essential for the rational design of methane mitigation strategies from livestock.

Assessing the impact of various ensilage factors on the fermentation of grass silage using conventional culture and bacterial community analysis techniques

AIMS

Grass silage is an important ruminant feedstuff on farms during winter. The ensilage of grass involves a natural lactic acid bacterial fermentation under anaerobic conditions, and numerous factors can influence the outcome of preservation. The aim of this study was to investigate the effect of dry matter concentration, ensiling system, compaction and air infiltration on silage bacterial community composition.

METHODS AND RESULTS

The impact of these factors was examined using conventional methods of microbial analysis and culture-independent Terminal Restriction Fragment Length Polymorphism (T-RFLP). Silage fermentation was restricted in herbage with a high dry matter concentration, and this was reflected in a shift in the bacterial population present. In contrast, ensiling system had little effect on bacterial community composition. Air infiltration, in the absence of compaction, altered silage bacterial community composition and silage pH.

CONCLUSIONS

Dry matter concentration and the absence of compaction were the main factors affecting silage microbial community composition, and this was reflected in both the conventional culture-based and T-RFLP data.

SIGNIFICANCE AND IMPACT OF THE STUDY

T-RFLP proved a useful tool to study the factors affecting ensilage. Apart from monitoring the presence or absence of members of the population, shifts in the relative presence of members could be monitored.

Histological grading of epithelial ovarian carcinomas

The grade of an ovarian epithelial neoplasm provides useful information. However, different approaches to grading exist and many ovarian cancers are not graded. We examined primary ovarian cancers from patients treated at our hospital and applied the 'universal' grading system. We found a significant association between grade and clinical stage, with a survival difference between grades for low-stage tumours. The application of grade is discussed in the light of developments in the grading of other gynaecological cancers.

The role of placental cytogenetic cultures in intrauterine and neonatal deaths

Knowledge of chromosomal status is useful in helping to explain fetal and neonatal deaths, but maceration has been felt to compromise the success rate. As well as skin fibroblast culture, the placenta can be sampled and this may be useful where permission for autopsy is refused. We examined placental cytogenetic results from 250 cases over a 5-year period. There was a success rate of 84.4%, with neither weight (< or > 500 g) nor maceration status showing a significant impact. Placentas sampled within 1 day were significantly more likely to give a positive culture. The results suggested that placental cytogenetic cultures should be attempted in all perinatal deaths where such information is desired.

Radial scars/complex sclerosing lesions and malignancy in a screening programme: incidence and histological features revisited

AIMS

Radial scars (RS) are benign entities, frequently identified on screening mammography, which may be associated with malignancy. Much debate has been generated with regard to the optimum management of RS. We present our experience of RS in the first 5 years of a screening programme. The aim was to evaluate (i) the incidence of atypia and malignancy and (ii) the value of the preoperative core biopsy. We also further characterize the histological features.

METHODS AND RESULTS

One hundred and twenty-five histologically confirmed cases of RS were reviewed (111 had preoperative biopsies). Thirty-one (24.8%) patients had a final malignant diagnosis (11 with invasive malignancy) and 28 (22.4%) showed atypia (including lobular carcinoma in situ). In those with core biopsies and a final malignant diagnosis, 12 cases were categorized as B5 (41.3%), three as B4 (10.3%), 12 as B3 (41.3%) and two as B2 (7%). Common histological features included obliterated ducts and chronic inflammation with, less frequently, neural hyperplasia (16.8%) and perineural invasion (3.2%).

CONCLUSIONS

The high incidence of atypia and malignancy identified in our study justifies our policy of removing all mammographically detected RS. We emphasize the utility of preoperative core biopsy evaluation in permitting one-stage surgical therapy in those with B5 diagnoses.

Microbial community changes during the bioremediation of creosote-contaminated soil

AIMS

To investigate the effects of aeration on the ex situ biodegradation of polycyclic aromatic hydrocarbons (PAHs) in creosote-contaminated soil and its effect on the microbial community present.

METHODS AND RESULTS

Aerated and nonaerated microcosms of soil excavated from a former timber treatment yard were maintained and sampled for PAH concentration and microbial community changes by terminal restriction fragment length polymorphism (TRFLP) analysis. After an experimental period of just 13 days, degradation was observed with all the PAHs monitored. Abiotic controls showed no loss of PAH. Results unexpectedly showed greater loss of the higher molecular weight PAHs in the nonaerated control. This may have been due to the soil excavation causing initial decompaction and aeration and the resulting changes caused in the microbial community composition, indicated by TRFLP analysis showing several ribotypes greatly increasing in relative abundance. Similar changes in both microcosms were observed but with several possible key differences. The species of micro-organisms putatively identified included Bacilli, pseudomonad, aeromonad, Vibrio and Clostridia species.

CONCLUSIONS

Excavation of the contaminated soil leads to decompaction, aeration and increased nutrient availability, which in turn allow microbial biodegradation of the PAHs and a change in the microbial community structure.

SIGNIFICANCE AND IMPACT OF THE STUDY

Understanding the changes occurring in the microbial community during biodegradation of all PAHs is essential for the development of improved site remediation protocols. TRFLP allows useful monitoring of the total microbial community.

Marrow aplasia developing 13 years after HLA-identical sibling allogeneic transplantation for chronic myeloid leukaemia: successful treatment with antithymocyte globulin and peripheral blood stem cell infusion from the original donor

Secondary or late graft failure has been defined as the development of inadequate marrow function after initial engraftment has been achieved. We describe a case of profound marrow aplasia occurring 13 years after sibling allogeneic bone marrow transplantation for chronic myeloid leukaemia (CML) in first chronic phase. Although the patient remained a complete donor chimera, thereby suggesting that an unselected infusion of donor peripheral blood stem cells (PBSC) or bone marrow might be indicated, the newly acquired aplasia was thought to be immune in aetiology and some immunosuppression was therefore considered appropriate. Rapid haematological recovery was achieved after the infusion of unselected PBSC from the original donor following conditioning with anti-thymocyte globulin (ATG).

Biotransformation of halophenols using crude cell extracts of Pseudomonas putida F6

Crude cell extracts of Pseudomonas putida F6 transformed 4-substituted fluoro-, chloro-, bromo- and iodo-phenol without the exogenous addition of cofactors. The rate of substrate consumption decreased with increasing substituent size (F>Cl>Br>I). Biotransformations resulted in greater than 95% utilisation of the halogenated substrate. Product accumulation was observed in incubations with 4-chloro, 4-bromo- and 4-iodo-phenol. These products were identified as the corresponding 4-substituted catechols. Transformation of 4-fluorophenol did not result in the accumulation of the corresponding catechol; however, manipulation of the reaction conditions by incorporation of ascorbic acid culminated in the formation of 4-fluorocatechol. Cell extracts of P. putida F6 also showed activity towards a 3-substituted phenol, namely 3-fluorophenol, resulting in the formation of a single product, 4-fluorocatechol.

The quality and value of sudden infant death necropsy reporting in Ireland

BACKGROUND

Infant necropsies are important for identifying cause of death. Recently issued guidelines have recommended investigations to be performed following sudden unexpected death in infants.

AIMS

To evaluate the quality and value of infant postmortem reporting.

METHODS

Postmortem reports from 1994-1996 and 1998-2000 in Ireland were evaluated using the National Sudden Infant Death Register. Scoring was by a modification of the Rushton system based on the extent of the postmortem data. The finding of additional pathological information was also assessed.

RESULTS

Of the 274 cases registered during the selection period, reports were available for 245. Overall quality of necropsy reporting was below the minimum accepted standard in 55.5%; 47% of the necropsies were performed in regional paediatric pathology centres. The quality of necropsies performed in regional centres was significantly higher than those performed elsewhere. Although 86% of the cases were defined as sudden infant death syndrome (SIDS; no cause of death found), the finding of additional pathological information was significantly related to the extent of the necropsy. There was a significant improvement in the quality of necropsies after the postmortem guidelines were issued.

CONCLUSIONS

The overall quality of sudden unexpected infant death necropsies in Ireland is less than adequate. A minimum accepted standard of necropsy is required before a diagnosis of SIDS can be made. Although standards have improved recently, this study highlights the need to adhere to published guidelines and the importance of auditing the effect of introducing practice guidelines on clinical practice to complete the audit loop.

Tamoxifen and estrogen lower circulating lipoprotein(a) concentrations in healthy postmenopausal women

Data in the literature suggest that circulating levels of lipoprotein(a) [Lp(a)] and insulinlike growth factor I (IGF-I) respond similarly to therapy with growth hormone, estrogen, or tamoxifen. To more clearly document these relations, we designed a randomized, double-blind, placebo-controlled study of the effects of tamoxifen and continuous estrogen on circulating levels of Lp(a), IGF-I, and IGF binding protein 3 (IGFBP-3) in healthy postmenopausal women. Both estrogen and tamoxifen decreased serum levels of IGF-I to 30% below baseline during the 3 months of treatment, while IGFBP-3 levels were unchanged. Plasma Lp(a) levels decreased to 24% below baseline after 1 month of treatment with either estrogen or tamoxifen (P < .05 for estrogen only); after 3 months Lp(a) decreased to 34% below baseline with tamoxifen therapy (P < .05) but returned to only 16% below baseline with estrogen. The correlation between Lp(a) and IGF-I was highly significant (P < .0001). We conclude that (1) tamoxifen lowers plasma Lp(a) levels in healthy postmenopausal women, (2) the suppressive effects of tamoxifen and estrogen on circulating Lp(a) concentration diverge after the first month of therapy, and (3) circulating levels of Lp(a) and IGF-I are strongly correlated with each other, an indication that they may share regulatory influences.

Inhibition of inflammatory cell-mediated myelin oxidation and interleukin-1 beta generation by a 21-aminosteroid, U74500A

Inflammatory cell-mediated myelin injury may be an important cause of tissue damage in both acute and chronic central nervous system (CNS) disorders. The 21-aminosteroids are novel derivatives of methylprednisolone without obvious glucocorticoid or mineralocorticoid side effects. We evaluated the ability of 21-aminosteroid, U74500A, to inhibit oxidation of rat brain myelin by human polymorphonuclear leukocytes (PMN) and monocytes. Myelin samples, as confirmed by SDS-PAGE, were incubated with PMN or monocytes and 100 microM U74500A or vehicle. Myelin oxidation by both PMN and monocytes was significantly reduced by U74500A. These observations demonstrate that U74500A can inhibit myelin oxidation by inflammatory cells. Additionally, 100 microM U74500A significantly reduced production of interleukin 1-beta by monocytes exposed to myelin. The aminosteroids may be beneficial in CNS disorders where myelin injury by inflammatory cells appears to contribute, such as acute focal ischemia or multiple sclerosis.

The high maltose-producing alpha-amylase of the thermophilic actinomycete, Thermomonospora curvata

The alpha-amylase of Thermomonospora curvata catalyses the formation of very high levels of maltose from starch (73%, w/w) without the attendant production of glucose. The enzyme was produced extracellularly in high yield during batch fermentation in a 5-1 fermentor. Purification was achieved by ammonium sulphate fractionation, Superose-12 gel filtration and DEAE-Sephacel ion-exchange chromatography. The enzyme exhibited maxima for activity at pH 6.0 and 65 degrees C, had a relative molecular mass of 60,900-62,000 and an isoelectric point at 6.2. The exceptionally high levels of maltose produced and the unique action pattern exhibited on starch and related substrates indicate a very unusual maltogenic system. The predominance of maltose as the final end-product may be explained by the participation of reactions other than simple hydrolysis and the preferential cleavage of maltotriose from higher maltooligosaccharides. The enzyme exhibits very low affinity for maltotriose (Km = 7.7 x 10(-3) M) and its conversion to maltose is achieved by synthetic followed by hydrolytic events, which result in the very high levels of maltose observed and preclude glucose formation. This system is distinguished from other very high maltose-producing amylases by virtue of its high temperature maximum, very low affinity for maltotriose and the absence of glucose in the final saccharide mixture.

A 21-aminosteroid inhibits oxidation of human low density lipoprotein by human monocytes and copper

Oxidation of low density lipoprotein (LDL) leads to more rapid uptake by arterial wall macrophages and foam cell formation. Inhibiting LDL oxidation may impede these processes and offers a new mechanism to retard atherogenesis. The 21-aminosteroids, derived from methylprednisolone, are potent inhibitors of free radical production by stimulated monocytes and also are scavengers of lipid peroxyl radicals. The 21-aminosteroid, U74500A, was added to a mixture of low density lipoprotein cholesterol and human monocytes to which lipopolysaccharide was add to stimulate the monocytes. At a final concentration of 10 microM, U74500A reduced the production of lipid peroxidation from 6.10 +/- 1.11 to 0.84 +/- 0.16 nmol (mean +/- SEM) MDA equivalent/1 x 10(6) monocytes, as measured by a thiobarbituric acid reacting substance (TBARS) assay. Similarly 10 microns U74500A reduced Cu2+ induced LDL oxidation from 12.28 +/- 0.10 (in vehicle) to 0.49 +/- 0.12. These observations suggest that the 21-aminosteroids should be evaluated in animal models as a potential therapy to retard atherogenesis, especially considering their apparent lack of mineralocorticoid and glucocorticoid side-effects.

A 21-aminosteroid inhibits stimulated monocyte hydrogen peroxide and chemiluminescence measurements from MS patients and controls

Monocytes are recruited to active sites of multiple sclerosis (MS) demyelination and may promote local tissue injury by generating an inflammatory response, mediated in part by the production of toxic oxygen metabolites. Corticosteroids are frequently and effectively used to ameliorate MS exacerbations, despite inadequate knowledge about the mechanism. We assessed the effects of a 21-aminosteroid, U74500A, a new class of steroid derivatives without glucocorticoid or mineralocorticoid effects, on the production of hydrogen peroxide (H2O2) and chemiluminescence by stimulated monocytes harvested from 8 stable MS patients and age- and sex-matched controls. H2O2 measurements and chemiluminescence were significantly reduced in both groups by U74500A. These results demonstrate that 21-aminosteroids reduce production of toxic oxygen metabolites by monocytes and thus their inflammatory potential, suggesting that these agents may be potentially effective and safe treatment for MS exacerbations.

Dietary n-3 fatty acid supplementation reduces superoxide production and chemiluminescence in a monocyte-enriched preparation of leukocytes

Consuming substantial quantities of n-3 fatty acids reduces atherogenesis in experimental models of atherosclerosis. The mechanisms of this beneficial effect remain uncertain. Monocyte-derived tissue macrophages are associated with atherogenesis, and inhibition of monocyte inflammatory activity could, hypothetically, be helpful in preventing atherosclerosis. We observed that stimulated human monocyte and/or macrophage production of superoxide and the occurrence of monocyte chemiluminescence, two indices of monocyte inflammatory activity, were significantly reduced by the ingestion of 6 g n-3 fatty acids/d for 6 wk. This effect was associated with a reduction of stearic and arachidonic acids whereas eicosapentaenoic and docosahexaenoic acid concentrations rose significantly. These results indicate that modest dietary n-3 fatty acid supplementation can reduce stimulated human-monocyte free-radical production and may impair the capability of macrophages derived from monocytes to promote oxidation of low-density-lipoprotein cholesterol and associated cellular toxicity.

Dietary supplementation with omega-3 fatty acids prolongs platelet survival in hyperlipidemic patients with atherosclerosis

Enhanced dietary omega-3 fatty acid consumption is thought to be associated with a reduced incidence of atherothrombotic disorders. This effect may be mediated in part through suppression of in vivo platelet activity by omega-3 fatty acids. We observed that platelet survival, a sensitive indicator of in vivo platelet activity was prolonged from 6.4 +/- 1.5 days to 7.7 +/- 1.4 days by moderate amounts of dietary omega-3 fatty acid supplementation for 6 weeks in a group of hyperlipidemic patients with preexisting, established atherothrombotic disorders. This effect on platelet survival was associated with a decrease in platelet arachidonic acid levels from 26.7 +/- 3.5% to 20.9% +/- 2.5% and a rise in platelet eicosapentaenoic and docosahexaenoic acid measurements from essentially undetectable to 2.8% +/- 1.6% and 1.9% +/- 1.0%. Plasma total cholesterol, low-density lipoprotein cholesterol, and serum apolipoprotein B levels rose significantly during the omega-3 fatty acid supplementation period. Platelet aggregation did not change. This study demonstrates that a modest amount of dietary omega-3 fatty acid supplementation can significantly effect in vivo platelet activity in a population at high risk for recurrent atherothrombotic disorders.