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Biomedical subjects

C Thomson

Publications and source records attributed to C Thomson.

At least 19 recordsLinked to original sources
PubMed2001

Reduction in fat intake is not associated with weight loss in most women after breast cancer diagnosis: evidence from a randomized controlled trial.

BACKGROUND: A reduction in dietary fat intake has been suggested as a method to promote weight loss in women at risk for breast cancer recurrence. METHODS: Weight change in response to diet intervention was examined in 1010 women who had completed treatment for Stage I, Stage II, or Stage IIIA (American Joint Committee on Cancer staging system) primary operable breast cancer during their first year of participation in a randomized, controlled, diet intervention trial to reduce risk of recurrence. Diet intervention was performed by telephone counseling and promoted a low fat diet that also was high in fiber, vegetables, and fruit. The comparison group was provided with general dietary guidelines to reduce disease risk. Multiple linear regression models were used to examine the relations among demographic and personal characteristics, changes in diet composition and exercise level, and change in body weight or body mass index. RESULTS: The average weight change in the 1-year period was 0.04 kg for the intervention group and 0.46 kg for the comparison group. For the total group, body weight was stable (+/- 5% baseline weight) for 743 women (74%), whereas 114 (11%) lost weight, and 153 (15%) gained weight. These distributions were similar in the two study groups inclusive of all study participants and for only those women with a baseline body mass index of > or = 25 kg/m2. Initial body mass index and changes in fiber and vegetable intakes, but not change in percent of energy obtained from fat, were associated independently with change in weight or body mass index. CONCLUSIONS: For most women at risk for breast cancer recurrence, diet intervention to promote a reduction in fat intake was not associated with significant weight loss. Testing the effect of a substantial change in diet composition on risk for breast cancer recurrence is unlikely to be confounded by weight loss in subjects who were the recipients of intensive intervention efforts.

Adult↗
PubMed2001

Palatability of bird repellents to Rattus norvegicus.

The palatability to captive, mostly laboratory-bred, Norway rats (Rattus norvegicus) of cereal-based baits containing 0.02 g kg-1 brodifacoum, with and without bird-repellent additives, was compared in a no-choice experimental design. Methyl anthranilate (25 g kg-1), dimethyl anthranilate (25 g kg-1) and cinnamamide (2.5 g kg-1) reduced bait consumption by the rats, but all except one rat ate enough bait to receive a lethal dose. Cinnamamide (1 g kg-1), ortho-aminoacetophenone (0.1 g kg-1) and tannic acid (20 g kg-1) did not reduce bait consumption and all rats died after eating baits. The concentration of cinnamamide palatable to rats has only a low and short-lived repellency to birds, so it does not warrant further investigation. However, ortho-aminoacetophenone and tannic acid should now be field-tested for palatability to all three rat species in New Zealand and for repellency to native New Zealand birds.

4-Hydroxycoumarins↗
PubMed2001

Evidence for prebudding arrest of ER export in animal cell mitosis and its role in generating Golgi partitioning intermediates.

During mitosis the interconnected Golgi complex of animal cells breaks down to produce both finely dispersed elements and discrete vesiculotubular structures. The endoplasmic reticulum (ER) plays a controversial role in generating these partitioning intermediates and here we highlight the importance of mitotic ER export arrest in this process. We show that experimental inhibition of ER export (by microinjecting dominant negative Sar1 mutant proteins) is sufficient to induce and maintain transformation of Golgi cisternae to vesiculotubular remnants during interphase and telophase, respectively. We also show that buds on the ER, ER exit sites and COPII vesicles are markedly depleted in mitotic cells and COPII components Sec23p, Sec24p, Sec13p and Sec31p redistribute into the cytosol, indicating ER export is inhibited at an early stage. Finally, we find a markedly uneven distribution of Golgi residents over residual exit sites of metaphase cells, consistent with tubulovesicular Golgi remnants arising by fragmentation rather than redistribution via the ER. Together, these results suggest selective recycling of Golgi residents, combined with prebudding cessation of ER export, induces transformation of Golgi cisternae to vesiculotubular remnants in mitotic cells. The vesiculotubular Golgi remnants, containing populations of slow or nonrecycling Golgi components, arise by fragmentation of a depleted Golgi ribbon independently from the ER.

COP-Coated Vesicles↗
PubMed2001

Dependent behaviours and beliefs: a qualitative study of older long-term smokers with arterial disease.

AIMS: To examine the reasons for continuing to smoke provided by a sample of long-term older smokers who have arterial disease (a smoking-related condition) and the implications of those beliefs for current smoking behaviour and future smoking intent. DESIGN: Qualitative semi-structured interview study with face-to-face interviews using 'life grids'. Setting and participants. Twenty-two long-term older smokers, with arterial disease, who were participants of a larger qualitative study of Life Course Influences on Patterns of Persistent Smoking. MEASUREMENT: Qualitative semi-structured interviews explored how respondents' described their relationship to smoking, using life grids to capture changes in patterns of cigarette usage across the life course. FINDINGS: Older smokers with arterial disease defined their relationship to smoking in either dependent terms or functional terms (to fulfil specific purposes). The two types of relationship appeared to be associated more with different degrees of control smokers described exercising over their habit than with their levels and patterns of usage. Some older smokers with arterial disease who showed dependent patterns of behaviour did not believe they were dependent, and some who showed non-dependent patterns of usage did not think of themselves as smokers even though they smoked. The immediate, functional and material benefits which these smokers attributed to smoking appeared to outweigh anticipated immediate and/or long term health-related benefits of quitting. CONCLUSIONS: How smokers define their relationship to cigarettes does not necessarily correspond to levels and patterns of usage.

Aged↗
PubMed2001

Assisting people with a low income to start and maintain their own community kitchens.

Q'wlut tu cicut ("My Parents Are Cooking") is a community kitchen program designed to help low-income people to facilitate their own cooking groups. Participants attended 20 weeks of instruction and received practical experience in topics such as meal planning, cooking, communication, and team building. At the end of 20 weeks, each participant was assisted in recruiting other people to start their own cooking group. To support the formation of these secondary groups, program staff and cooking group leaders met every second week for a further ten weeks. Another 30-week session has taken place since the initial session. The program had a high rate of completion. Each of the 24 participants who completed the program recruited an additional two to four people and started a cooking group with these people. Four months after completion of the first session, 80% of participants were facilitating their own cooking groups. After eight months, 50% of participants were still cooking in groups. All participants who completed the program stated that they had met their food- and nutrition-related goals, and they cited numerous program benefits to themselves and their families.

Budgets↗
PubMed2000

Interventions for treating plantar heel pain.

BACKGROUND: Ten percent of people may experience pain under the heel (plantar heel pain) at some time. Injections, insoles, heel pads, strapping and surgery have been common forms of treatment offered. The absolute and relative effectiveness of these interventions are poorly understood. OBJECTIVES: The objective of this review was to identify and evaluate the evidence for effectiveness of treatment in treating plantar heel pain. SEARCH STRATEGY: MEDLINE (from 1966 to December 1997), EMBASE and the Cochrane Library were searched. Three podiatry journals (The Foot, The Chiropodist (later The Journal of British Podiatric Medicine), and The British Journal of Podiatric Medicine) were handsearched. We contacted known investigators in the field to identify unpublished data or research in progress. Non English language reports were excluded from the review. SELECTION CRITERIA: Randomised and quasi randomised trials of interventions for plantar heel pain in adults. DATA COLLECTION AND ANALYSIS: Two reviewers independently evaluated studies for inclusion, extracted data and assessed study quality. Additional information was obtained by direct contact with investigators. No poolable data were identified. Where measures of variance were available we have calculated the weighted mean differences based on visual analogue scale (VAS) scores. MAIN RESULTS: Eleven randomised trials involving 465 participants were included. Study quality was generally poor, and pooling of data was not possible. All studies measured a reduction in heel pain as the primary outcome. Seven trials evaluated interventions against placebo/dummy or no treatment. There was limited evidence for the effectiveness of topical corticosteroid, administered by iontophoresis in reducing pain. There was no evidence for the effectiveness of injected corticosteroid. There was limited evidence for the effectiveness of low energy extracorporeal shock wave therapy in reducing night pain, resting pain and pressure pain in the short term (12 weeks). In individuals with chronic pain (longer than six months), there was limited evidence for the effectiveness of dorsiflexion night splints in reducing pain. There was no evidence to support the effectiveness of therapeutic ultrasound, low-intensity laser therapy, exposure to an electron generating device or insoles with magnetic foil. No randomised trials evaluating orthotic devices, surgery, or radiotherapy against a control population were identified. There was limited evidence for the superiority of corticosteroid injections over orthotic devices. REVIEWER'S CONCLUSIONS: Although there is limited evidence for the effectiveness of local corticosteroid therapy, the effectiveness of other frequently employed treatments in altering the clinical course of plantar heel pain has not been established in comparative studies. Well designed and conducted randomised studies are required.

Adrenal Cortex Hormones↗
PubMed2000

The distribution of carbonic anhydrase II in human, pig and rat oesophageal epithelium.

Carbonic anhydrase II (CA II) is present in human oesophageal epithelial cells and probably involved in protecting the mucosa against acidic gastric refluxate. If this is the case, then it is likely that the enzyme will be more concentrated at or near the gastro-oesophageal junction. To answer this question, and determine whether CA II is present and similarly distributed in other species, we also examined the oesophageal epithelium of the rat and pig. In the rat, CA II was largely absent from the oesophageal epithelium, but present in the stratified squamous epithelium of the gastric forestomach as an approximately 2 mm-long collar around the entrance to the corpus, a site that roughly corresponds to the gastro-oesophageal junction in other animals. The enzyme was present mainly in basal and prickle cells. In upper and middle pig oesophagus, CA II was largely confined to basal cells and isolated groups of stratified superficial prickle cells. CA II-containing epithelial cells were highly concentrated in the thickened epithelium at the gastro-oesophageal junction (about four-times thicker than upper or middle). Reactive cells were present throughout the depth of the epithelium, but noticeably more concentrated in the basal and superficial prickle cell layers. CA II was also prominent in the most superficial cell layers in islands of the oesophageal mucosa within the gastric cardia. In man, CA II was confined largely to the basal half of the epithelium in the upper and middle regions of oesophagus. The distribution of CA II at the gastro-oesophageal junction took different forms. In general, there were more CA II-reactive cells at or closer to the lumen. The superficial prickle cell layers tended to exhibit more CA II than the deeper layers, with basal and epibasal cells containing little or no enzyme. In other regions of the same specimens, CA II-containing cells were present from the basal to the most luminal layers. If CA II in oesophageal epithelial cells in the region of the gastro-oesophageal junction (or in the case of the rat the forestomach/corpus junction) is important in the defence against refluxate, then it is in a vulnerable site, since bile salts are potent inhibitors of the enzyme. The action of bile salts on CA II may be an important factor in the initiation of oesophageal disease.

Animals↗
PubMed2000

Gene-target recognition among members of the myc superfamily and implications for oncogenesis.

Myc and Mad family proteins regulate multiple biological processes through their capacity to influence gene expression directly. Here we show that the basic regions of Myc and Mad proteins are not functionally equivalent in oncogenesis, have separable E-box-binding activities and engage both common and distinct gene targets. Our data support the view that the opposing biological actions of Myc and Mxi1 extend beyond reciprocal regulation of common gene targets. Identification of differentially regulated gene targets provides a framework for understanding the mechanism through which the Myc superfamily governs the growth, proliferation and survival of normal and neoplastic cells.

3T3 Cells↗
PubMed2000

Alfuzosin-induced hepatotoxicity.

Drug-induced hepatic injury is a potential complication of virtually all drugs because the liver is central to the metabolic disposition of almost all drugs, although precise mechanisms often are unknown. We report a case of severe acute mixed hepatitis (cholestatic and hepatocellular), probably induced by alfuzosin. This event has not been reported previously (MEDLINE 1990, March 1999). Viral causes, autoimmune hepatitis and biliary tree obstruction were excluded. After discontinuation of the drug, liver function test results returned to normal.

Acute Disease↗
PubMed1999

Fine specificity and MHC restriction of trinitrophenyl-specific CTL.

In this study, the fine specificity and MHC restriction of a CTL response specific to the trinitrophenyl (TNP) hapten was analyzed. Based on the structure of peptide/Kb complexes and ternary TCR/Ag/MHC complexes, four TNP peptides, two octamers, and two nonamers were chosen for eliciting anti-TNP CTL responses. Hapten was conjugated at position 4 in the octamers and at position 5 in the nonamers, positions which should allow engagement of the hapten by TCRs. Potent CTL activity for each of the TNP peptides was obtained that was highly hapten-specific; however, there were considerable differences in the extent of cross-reactivity with other TNP peptides, with the octamers generating more cross-reactive CTL than the nonamers. MHC restriction analysis suggested that anti-hapten responses were less dependent on MHC recognition than anti-peptide responses. This was evidenced by the relative ease of detecting cross-reactivity to haptenated peptides presented by allo-MHC and by the relative insensitivity of anti-hapten vs anti-peptide CTL to mutations in the Kb molecule at potential TCR interaction sites. One potential explanation for this insensitivity to MHC mutation was the finding that the anti-hapten response appeared to be of higher avidity, since a > 100-fold difference in the amount of Ag required to sensitize target cells was found between these two types of Ags.

Animals↗
PubMed1999

Changes in HIV/AIDS education, knowledge and attitudes among Scottish 15-16 year olds, 1990-1994: findings from the WHO: Health Behaviour in School-aged Children Study (HBSC).

There is concern about the high prevalence of adolescent sexual health problems, such as sexually transmitted diseases (STDs) and unwanted pregnancies, that currently exist in the UK. If young people are to reduce their risk from HIV/AIDS and other STDs it is imperative, in the first instance, they know what the risks are and how they can avoid them. However, effective school-based sex education can only be delivered if there are accurate data on young people's current levels of knowledge and existing sex education needs. This paper details findings from the WHO: Health Behaviours of School-aged Children Study on the changes that have occurred between 1990 and 1994 in Scottish school-children's knowledge, attitudes and perceived educational needs in relation to HIV/AIDS. There have been significant changes in knowledge and attitudes that may affect their sexual behaviour, e.g. in their attitudes to condom use, risk of HIV/AIDS and other STDs, and also other sexual health problems, such as the risk of unwanted pregnancies and abortions. Finally, areas that require future research and recommendations for future sexual health education interventions are highlighted.

Adolescent↗
PubMed1998

Axonal swellings and degeneration in mice lacking the major proteolipid of myelin.

Glial cells produce myelin and contribute to axonal morphology in the nervous system. Two myelin membrane proteolipids, PLP and DM20, were shown to be essential for the integrity of myelinated axons. In the absence of PLP-DM20, mice assembled compact myelin sheaths but subsequently developed widespread axonal swellings and degeneration, associated predominantly with small-caliber nerve fibers. Similar swellings were absent in dysmyelinated shiverer mice, which lack myelin basic protein (MBP), but recurred in MBP*PLP double mutants. Thus, fiber degeneration, which was probably secondary to impaired axonal transport, could indicate that myelinated axons require local oligodendroglial support.

Animals↗
PubMed1998

Current concepts of PLP and its role in the nervous system.

Proteolipid protein (PLP) and its smaller isoform DM20 constitute the major myelin proteins of the CNS. Mutations of the X-linked Plp gene cause the heterogeneous syndromes of Pelizaeus-Merzbacher disease (PMD) and spastic paraplegia (SPG) in man and similar dysmyelinating disorders in a range of animal species. A variety of mutations including missense mutations, deletions, and duplications are responsible. Missense mutations cause a predicted alteration in primary structure of the encoded protein(s) and are generally associated with early onset of signs and generalised dysmyelination. The severity of the phenotype varies according to the particular codon involved and the influence of uncharacterised modifying genes. There is some evidence that the dysmyelination results from the altered protein acquiring a novel function deleterious to the oligodendrocyte's function. Transgenic mice carrying extra copies of the Plp gene provide a valid model of PMD/SPG due to gene duplication. Depending on the gene dosage, the phenotype can vary from early onset of severe and lethal dysmyelination through to a very late onset of a tract-specific demyelination and axonal degeneration. Mice with a null mutation of the Plp gene assemble and maintain normal amounts of myelin but develop a progressive axonopathy, again demonstrating tract specificity. The results indicate that the functions of PLP are far from clear. There is good evidence that it is involved in the formation of the intraperiod line of myelin, and the results from the knockout and transgenic mice suggest a role in the interaction of oligodendrocyte and axon.

Animals↗
PubMed1998

Two-color hybridization assay for simultaneous detection of Bordetella bronchiseptica and toxigenic Pasteurella multocida from swine.

Bordetella bronchiseptica and toxigenic Pasteurella multocida are the etiologic agents of swine atrophic rhinitis. Methods currently used for their identification are time-consuming and suffer from a lack of sensitivity. We describe a colony lift-hybridization assay for detection of B. bronchiseptica and toxigenic P. multocida that can be performed with a single colony lift derived from a primary isolation plate without the need for pure subcultures of suspect bacteria. Membranes are hybridized simultaneously to probes derived from the B. bronchiseptica alcA gene and the P. multocida toxA gene. A multicolor development procedure permits sequential detection of bound probes. The assay was tested with 84 primary isolation plates generated from nasal swabs from swine with clinical signs of atrophic rhinitis. Comparison of the results from the colony lift-hybridization assay with those from conventional testing, based on a combination of colony morphology, biochemical reactions, mouse lethality, and enzyme-linked immunosorbent assay, indicated that the colony lift assay has superior sensitivity and comparable specificity. This technique has wide application for diagnostic and experimental studies.

ADP Ribose Transferases↗
PubMed1998

Cholesteryl ester transfer protein mutations, protein activity and HDL-cholesterol concentration.

We have examined a group of North American subjects, selected to include individuals with a wide variety of HDL-cholesterol concentrations for: 1) mutations in the genes coding for cholesteryl ester transfer protein and hepatic lipase, 2) apolipoprotein E genotype, 3) total cholesterol and triglycerides, 4) HDL-triglycerides. Cholesteryl ester transfer protein activity was also estimated, using a novel technique that does not require separation of substrate and product. Transfer activity was shown to have a monophasic distribution, with a mean activity of 21 pmol substrate transferred/3 h/microl plasma. The cholesterol ester transfer activity of the group with HDL-cholesterol >1.60 mmol/l was significantly less than those with HDL-cholesterol <1.60 mmol/l. The cholesteryl ester transfer protein G1533A mutation was detected at an overall allele frequency of 2.91%. The mutation was more frequent in the group with HDL-cholesterol <1.60 mmol/l than in those >1.60 mmol/l. It was also more frequent in those with protein activity > 30 pmol/ 3h/microl plasma than in those with activity <30. These data suggest that this mutation in cholesteryl ester transfer protein is associated with increased transfer activity and reduced HDL-cholesterol concentrations. The cholesteryl ester transfer protein activity assay described here is simple and convenient. Subject to further evaluation and correlation with the present labour and time intensive assays, this commercially available assay offers the potential of rapid, simple analysis of large numbers of samples.

Carrier Proteins↗
PubMed1997

Carbonic anhydrase isoenzymes I, II, III, and IV are present in human esophageal epithelium.

Carbonic anhydrase (CA) isoenzymes have been widely studied in the gastrointestinal tract, where they mediate membrane transport events and pH regulation. However, the esophagus has generally received scant attention. In an immunohistochemical study confirmed by Western blotting, we have detected for CA isoenzymes (CAI, II, III, and IV) in the epithelium of human esophagus. Isoenzymes I, III, and sometimes IV (< 10%) were present in the cytoplasm of basal cells and II and IV in the cytoplasm and cell surface membranes, respectively, of suprabasal cells (prickle cells). The localization of CAIV to the plasma membranes was confirmed by electron microscopic immunocytochemistry. CA was effectively divided at the basal-suprabasal interface between low-activity CAI and III (basal) and high-activity CAII and IV (suprabasal). Carbonic anhydrase in esophageal epithelial cells may have several functions: elimination of CO2 and metabolites, participation in membrane transport events during active cell growth, and pH regulation as a protective mechanism against acidic gastric reflux.

Blotting, Western↗