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Biomedical subjects

T Beresford

Publications and source records attributed to T Beresford.

12 recordsLinked to original sources
PubMed2001

The limits of philosophy in liver transplantation.

At the Editor's request, Dr. Beresford reviews the paper by Martens, with particular reference to the clinical literature on liver transplantation in alcoholism. He concludes that abstract concepts, such as responsibility for one's illness, may have some theoretical value in academic discussions but that no studies support any direct practical usefulness for them in patient selection for solid organ transplantation. Rather, a sizeable body of work delineates a practical clinical approach to the evaluation of alcohol-dependent persons who request liver transplantation. He highlights the relevant aspects of this work briefly.

Humans↗
PubMed2001

Spatial and temporal distribution of non-starter lactic acid bacteria in Cheddar cheese.

AIMS: The aim of this work was to investigate the spatial and temporal distribution of species and strains of non-starter lactic acid bacteria (NSLAB) within Cheddar cheese. METHODS AND RESULTS: Randomly amplified polymorphic DNA was used to identify and track the principle species and strain groups of NSLAB present. The same strains dominated each location examined within a cheese at any particular time point. Temporal change in species and strains of NSLAB during ripening was observed. A mixture of Lactobacillus paracasei, Lact. plantarum, Lact. rhamnosus and unidentified strains was found up to 6 weeks of maturation, thereafter only Lact. paracasei strains were isolated. CONCLUSION: Little variation in the spatial distribution of NSLAB strains occurs within Cheddar cheese; however, temporal changes in the species and strains were observed during ripening. SIGNIFICANCE AND IMPACT OF THE STUDY: The complex changes in the composition of the NSLAB community of Cheddar cheese may be the source of the variation in flavour that is seen in commercial practice.

Cheese↗
PubMed2000

Combination of hydrostatic pressure and lacticin 3147 causes increased killing of Staphylococcus and Listeria.

The use of hydrostatic pressure and lacticin 3147 treatments were evaluated in milk and whey with a view to combining both treatments for improving the quality of minimally processed dairy foods. The system was evaluated using two foodborne pathogens: Staphylococcus aureus ATCC6538 and Listeria innocua DPC1770. Trials against Staph. aureus ATCC6538 were performed using concentrated lacticin 3147 prepared from culture supernatant. The results demonstrated a more than additive effect when both treatments were used in combination. For example, the combination of 250 MPa (2.2 log reduction) and lacticin 3147 (1 log reduction) resulted in more than 6 logs of kill. Similar results were obtained when a foodgrade powdered form of lacticin 3147 (developed from a spray dried fermentatation of reconstituted demineralized whey powder) was evaluated for the inactivation of L. innocua DPC1770. Furthermore, it was observed that treatment of lacticin 3147 preparations with pressures greater than 400 MPa yielded an increase in bacteriocin activity (equivalent to a doubling of activity). These results indicate that a combination of high pressure and lacticin 3147 may be suitable for improving the quality of minimally processed foods at lower hydrostatic pressure levels.

Animals↗
PubMed1999

A twin study of drinking and smoking onset and latencies from first use to regular use.

The early onset of alcohol and tobacco use has been associated with increased risk for later substance abuse and dependence problems. This study investigated genetic and environmental influences on age at onset of alcohol and tobacco use by examining twin resemblance for several retrospectively reported onset milestones including age at first use, age at first alcohol intoxication experience, and age at regular use. In addition, we also examined the latency between age at first use and age at regular use of tobacco and alcohol. The subjects were a volunteer sample of older adult twins 50 to 96 years of age. MZ twin correlations for age at first alcohol use and age at first tobacco use were .57 and .44, respectively, compared to .45 and .37 for DZ same-sex twins. MZ twins correlated .30 and .26 for the latencies between first use and regular use of alcohol and of tobacco, while DZ correlations were -.01 and .05, respectively. Biometrical model-fitting results confirmed that familial resemblance for age at first use for both alcohol and tobacco was largely the result of shared environmental factors, while the latencies between first use and regular patterns of use were more genetically influenced. These findings add to a growing body of literature suggesting that initiation of substance use is influenced primarily by environmental rather than genetic factors.

Adolescent↗
PubMed1999

Phenotypic and genotypic characterization of non-starter lactic acid bacteria in mature cheddar cheese.

Non-starter lactic acid bacteria were isolated from 14 premium-quality and 3 sensorially defective mature Irish Cheddar cheeses, obtained from six manufacturers. From countable plates of Lactobacillus-selective agar, 20 single isolated colonies were randomly picked per cheese. All 331 viable isolates were biochemically characterized as mesophilic (i.e., group II) Lactobacillus spp. Phenotypically, the isolates comprised 96.4% L. paracasei, 2.1% L. plantarum, 0.3% L. curvatus, 0.3% L. brevis, and 0.9% unidentified species. Randomly amplified polymorphic DNA (RAPD) analysis was used to rapidly identify the dominant strain groups in nine cheeses from three of the factories, and through clustering by the unweighted pair group method with arithmetic averages, an average of seven strains were found per cheese. In general, strains isolated from cheese produced at the same factory clustered together. The majority of isolates associated with premium-quality cheese grouped together and apart from clusters of strains from defective-quality cheese. No correlation was found between the isomer of lactate produced and RAPD profiles, although isolates which did not ferment ribose clustered together. The phenotypic and genotypic methods employed were validated with a selection of 31 type and reference strains of mesophilic Lactobacillus spp. commonly found in Cheddar cheese. RAPD analysis was found to be a useful and rapid method for identifying isolates to the species level. The low homology exhibited between RAPD banding profiles for cheese isolates and collection strains demonstrated the heterogeneity of the L. paracasei complex.

Bacterial Typing Techniques↗
PubMed1999

Hippocampal to pituitary volume ratio: a specific measure of reciprocal neuroendocrine alterations in alcohol dependence.

OBJECTIVE: Studies to date provide conflicting views of the relationship between corticosteroids and decreased hippocampal volume in alcoholism. If this were mediated through the hypothalamic-pituitary-adrenal (HPA) axis, enlarged pituitary volumes relative to hippocampal volumes might be expected and be measurable using the hippocampus to pituitary volume (H:P) ratio. METHOD: Using magnetic resonance imaging (MRI), we performed volumetric analysis of the pituitary and hippocampus on 10 subjects with alcohol dependence (AD) and on 10 normal control subjects. RESULTS: Compared to normal controls, AD subjects demonstrated a trend towards decreased hippocampal volume (p < .06) and increased pituitary volume (p < .07). More importantly, H:P ratios were significantly smaller in AD subjects (p < .01). This observation persisted even when covaried for age. CONCLUSIONS: Reduced H:P ratio fits the hypothesis that ethanol stimulates pituitary corticotrophs resulting in elevated corticosteroid levels and possible injury to the hippocampus. If replicated, reduced H:P ratio may serve as a clinical measure of reciprocal neuroendocrine changes in chronic heavy ethanol use.

Adrenal Cortex Hormones↗
PubMed1998

Effect of altering the daily herbage allowance to cows in mid lactation on the composition, ripening and functionality of low-moisture, part-skim Mozzarella cheese.

Milk was collected from three spring-calving herds, on different daily herbage allowances (DHA) of perennial rye-grass (16, 20 or 24 kg dry matter (DM)/cow for a 17 week period. On five occasions, at weekly intervals in the middle of the period, the three different milks were converted into low-moisture part-skim Mozzarella cheese. Increasing the DHA resulted in significant increases in the concentrations of protein in the cheesemilk (P < 0.05) and cheese whey (P < 0.02). The moisture-adjusted cheese yield increased significantly (P < 0.01) on raising the DHA from 16 to 24 kg grass DM/cow. DHA had no significant effects on any of the gross compositional values of the cheese (although moisture and fat-in-DM levels tended to decrease and increase respectively with increasing DHA). The hardness of the uncooked cheese and functionality of cooked cheese (i.e. melt time, flowability, stretch and viscosity) were not significantly influenced by DHA over the 115 d ripening period at 4 degrees C.

Animals↗
PubMed1993

Physiological and genetic regulation of rRNA synthesis in Lactococcus.

The macromolecular composition of Lactococcus was regulated by growth rate in the same general way as that of less fastidious bacteria such as Escherichia coli and Salmonella typhimurium. The ratios of RNA:DNA and RNA:protein increased approximately threefold over a 13.5-fold increase in growth rate, whereas the ratio of DNA:protein remained approximately constant. Using reporter genes fused to a DNA fragment of a cloned lactococcal rRNA operon, promoter activity was located upstream of the 16S rRNA structural gene. This DNA fragment had some characteristics typical of a rrn promoter in E. coli. Two consensus promoter sequences P1 and P2 were located 296 and 157 bp, respectively, upstream of the start of the 16S rRNA gene. Between P2 and the start of the 16S rRNA gene, sequences were identified with typical anti-termination motifs characteristic of E. coli rrn promoter regions. A putative transcription terminator sequence was identified downstream of the 5S rRNA gene and putative primary RNA transcript processing sites at both ends of the lactococcal rRNA operon were also noted.

Amino Acid Sequence↗
PubMed1991

Cloning and partial characterization of genes for ribosomal ribonucleic acid in Lactococcus lactis subsp. lactis.

A cosmid gene library of the genome of Lactococcus lactis subsp. lactis 712 was probed for the presence of 16S rRNA genes, using 32P 5' end-labelled 16S rRNA fragments. Cosmid DNA from positive clones responsible for hybridisation was subcloned into a high copy number vector and a restriction map was constructed. The location of the 16S, 23S and 5S rRNA genes was determined on this map. Transcriptional promoter activity was identified upstream of the 5' end of the 16S rRNA gene. By probing L. lactis 712 chromosomal DNA cut with a range of restriction endonucleases, with a conserved oligonucleotide to the 5' end of the 16S rRNA gene, 6 copies of rRNA genes were identified.

Base Sequence↗
PubMed1982

Alcoholism assessment on an orthopaedic surgery service.

We reviewed the initial history, obtained by the orthopaedic house staff, of each of eighty-seven patients who were consecutively admitted to an acute orthopaedic-surgery service. A diagnosis of alcoholism was made by the house staff in only one of every ten patients who had been identified as having symptoms of alcohol addiction in a previous study. Alcohol abuse was identified in only five of every ten such patients. Of the orthopaedic patients in this sample who had been shown to be abusing alcohol, 37 per cent were neither suspected nor diagnosed as abusers by the orthopaedic house staff. We recommend the use of a brief screening interview (CAGE) to increase diagnostic effectiveness in this area, and discuss the clinical usefulness of an early diagnosis of alcoholism among orthopaedic surgical patients.

Adolescent↗