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Biomedical subjects

K McColl

Publications and source records attributed to K McColl.

At least 19 recordsLinked to original sources
PubMed2001

Helicobacter pylori infection reduces systemic availability of dietary vitamin C.

OBJECTIVE: Helicobacter pylori infection is recognized to lower the concentration of vitamin C in gastric juice. The objective of this study was to assess the effect of the infection on the systemic availability of dietary vitamin C. METHODS: The study involved 1,106 men and women aged 25-74 randomly recruited from the population of north Glasgow. Their H. pylori status, dietary vitamin C intake calculated from a food frequency questionnaire and plasma vitamin C concentration were measured. Correction was made for potential confounding factors such as age, sex, smoking and social status. RESULTS: The mean plasma vitamin C concentration in those who were H. pylori-positive was only 65% of that in those classified negative. Although partly explained by differences in age, sex, social class, smoking and vitamin C intake, the systemic reduction was observed across almost all sub-groups after stratification. Correction for all these factors still gave a plasma vitamin C level for H. pylori positives which was only 80% of that for negatives (P < 0.0001). CONCLUSIONS: H. pylori substantially impairs the bio-availability of vitamin C. This, together with the reduced vitamin C intake of H. pylori-positive subjects, markedly reduces the plasma vitamin C level of infected subjects. The reduced circulating levels of vitamin C in H. pylori-infected subjects may contribute to the aetiology of gastric cancer, as well as other diseases associated with anti-oxidant deficiency.

Adult↗
PubMed2000

Involvement of c-Fos in signaling grp78 induction following ER calcium release.

Release of calcium from the endoplasmic reticulum (ER) signals an increase in transcription of both the early response gene, c-fos, and the late response gene, grp78. We have used thapsigargin (TG), an ER calcium-ATPase pump inhibitor that induces calcium release from the ER, to investigate the possible involvement of c-Fos, a component of the AP-1 transcription factor, in grp78 induction. Two cell lines with markedly different responses to TG treatment were employed: the WEHI7.2 mouse lymphoma line in which TG fails to induce grp78, and the MDA-MB-468 mammary epithelial line in which TG induces grp78. In WEHI7.2 cells, TG-induced calcium release triggers a rapid increase in c-fos mRNA, but the level of c-Fos protein decreases due to degradation by the multicatalytic proteasome. C-FosdeltaC, a proteasome resistant c-Fos mutant with AP-1 activity similar to that of wild type c-Fos, restores grp78 induction in WEHI7.2 cells, detected by both Northern hybridization and a grp78 promoter-luciferase reporter assay. In MDA-MB-468 cells, TG-mediated calcium release induces a sustained elevation of c-Fos protein that precedes grp78 induction. A region of the grp78 promoter containing both ERSE and CORE regions, but missing TRE and CRE regions, is sufficient to mediate induction of reporter luciferase activity. Induction of this reporter was blocked by A-Fos, a dominant negative inhibitor of c-Fos. Also, the induction of grp78-luciferase reporter activity was inhibited by c-fos antisense mRNA. In summary, the findings indicate that c-Fos is involved in signaling grp78 induction following TG treatment, and that grp78 induction is inhibited by proteasome-mediated c-Fos degradation.

Breast↗
PubMed2000

An investigation into factors associated with Helicobacter pylori infection.

This study aims to estimate the prevalence of Helicobacter pylori in Glasgow, and to provide a systematic analysis of factors associated with this prevalence. The data used are from a random population sample of 793 men and 838 women aged 25-64 years conducted in 1995. The prevalence is estimated to be 66% (95% confidence interval: 63-68%); a level that is more typical of developing countries. Prevalence increases with age and social deprivation (P<0.0001) and is slightly higher in men than women (P = 0.07). After adjustment for age, social class, and sex group, H. pylori prevalence increases with increased cotinine (tobacco consumption) (P = 0.0005), increased number of siblings (P<0.0001), and decreased height (P = 0.03). Prevalence of coronary heart disease, hypertension, diabetes and intermittent claudication, alcohol consumption, fibrinogen, total serum cholesterol, HDL cholesterol, triglycerides, marital status, systolic and diastolic blood pressure had no independent association. The infection seems to be spread more readily in deprived, relatively crowded living conditions in childhood. The independent relationship with smoking suggests a possible second source of spread of infection in later years. The high degree of social deprivation in Glasgow is suggested as a major explanation of the high H. pylori prevalence found there.

Adult↗
PubMed2000

Quality assurance by a commercial flow cytometry method of leucodepletion of whole blood donations: initial application of universal testing and proposals for a batch-release sampling plan.

We have used the Becton-Dickinson LeucoCOUNT test to monitor residual leucocytes in whole blood by flow cytometry following leucodepletion filtration. This test was found to be quick, robust and reliable, and allowed measurement of residual leucocytes down to 2.25 x 104 leucocytes per unit, which was found to match approximately the limit of filter proficiency. The results of testing > 1000 units showed a lognormal distribution with means between log(10) 4.864 (0.73 x 105) and log(10) 5.016 (1.04 x 105) leucocytes per unit in the three different homogeneous groups of filtered units studied. The numbers of units with residual leucocytes exceeding the 5 x 106 upper threshold were 1/577, 2/457 and 0/87 in these groups. The filtration processes were validated according to the published BEST working party guidelines and were well within the 99% confidence and 95% tolerance target for the 5 x 106 upper threshold set for the UK. A sampling plan based on British Standard BS 6001 with elimination of outliers by the extreme studentized deviate (Grubbs' test) was evaluated on random samples from these groups and has been adopted locally as a prospective batch-release criterion for release of leucodepleted blood.

Blood Donors↗
PubMed2000

Should non-invasive Helicobacter pylori testing replace endoscopy in investigation of dyspepsia?

Our knowledge of Helicobacter pylori infection is now changing the way in which we investigate patients presenting with dyspepsia, with noninvasive H. pylori testing replacing endoscopy. Non-invasive H. pylori testing has been shown to be useful in predicting the underlying diagnosis in patients presenting with dyspepsia. Several studies have shown that 20-50% of dyspeptic patients with a positive H. pylori test will have evidence of underlying ulcer disease or duodenitis. In contrast, less than 5% of dyspeptic patients with a negative H. pylori test will have evidence of ulcer disease and in these subjects, the likeliest diagnosis is gastroesophageal reflux disease. This has led to many groups recommending that noninvasive H. pylori testing should be used in place of endoscopy, with all those testing positive being given anti-H. pylori therapy and those testing negative being treated symptomatically. One concern about nonendoscopic management of dyspeptic patients is the possibility of missing underlying malignancy but studies have shown that in western countries this is rare in patients less than 55 years of age presenting with dyspepsia in the absence of sinister symptoms. There is increasing evidence supporting eradication of H. pylori infection in dyspeptic patients without ulcer disease. Meta-analysis of four prospective randomized trials indicates that such treatment is superior to placebo in about 10% of subjects. H. pylori-positive dyspeptic patients are also recognized to have an increased risk of developing ulcer disease in the future which will be removed by treating the infection. Another justification for eradicating the infection in the absence of ulcer disease is the fact that H. pylori infection is now proven to be a risk factor for gastric cancer. Prospective randomized studies comparing endoscopy with noninvasive H. pylori testing in the management of dyspeptic patients indicate that managing dyspepsia by noninvasive H. pylori testing is at least as effective as endoscopic-based management in producing symptomatic resolution and saves a substantial number of endoscopic procedures. There is therefore now substantial evidence indicating that noninvasive H. pylori testing should be used in place of endoscopy to determine the management of younger dyspeptic patients without sinister symptoms and who are not taking nonsteroidal anti-inflammatory drugs.

Dyspepsia↗
PubMed1998

Symptomatic benefit from eradicating Helicobacter pylori infection in patients with nonulcer dyspepsia.

BACKGROUND: The eradication of Helicobacter pylori infection is beneficial in patients with gastric or duodenal ulcers. The value of eradicating the infection in patients with dyspepsia and no evidence of ulcer disease is not known. METHODS: We performed a randomized, placebo-controlled trial comparing the efficacy of treatment for two weeks with 20 mg of omeprazole orally twice daily, 500 mg of amoxicillin three times daily (with 500 mg of tetracycline three times daily substituted for amoxicillin in patients allergic to penicillin), and 400 mg of metronidazole three times daily (160 patients) with that of omeprazole alone (158 patients) for resolving symptoms of dyspepsia in patients with H. pylori infection but no evidence of ulcer disease on upper gastrointestinal endoscopy. Symptoms were assessed with the Glasgow Dyspepsia Severity Score, with resolution of symptoms defined as a score of 0 or 1 in the preceding six months (maximal score, 20). One year later the patients were assessed to determine the frequency of the resolution of symptoms. RESULTS: One month after the completion of treatment, 132 of 150 patients (88 percent) in the group assigned to received omeprazole and antibiotics had a negative test for H. pylori, as compared with 7 of 152 (5 percent) in the group assigned to receive omeprazole alone. One year later, dyspepsia had resolved in 33 of 154 patients (21 percent) in the group given omeprazole and antibiotics, as compared with 11 of 154 (7 percent) in the group given omeprazole alone (95 percent confidence interval for the difference, 7 to 22 percent; P<0.001). Among the patients in the group given omeprazole and antibiotics, the symptoms resolved in 26 of the 98 patients (27 percent) who had had symptoms for five years or less, as compared with 7 of the 56 patients (12 percent) who had had symptoms for more than five years (P=0.03). CONCLUSIONS: In patients with H. pylori infection and nonulcer, or functional, dyspepsia, treatment with omeprazole and antibiotics to eradicate the infection is more likely to resolve symptoms than treatment with omeprazole alone.

Adolescent↗
PubMed1989

Performance profiles of topical antimicrobials in vitro.

The in-vitro efficacy of commercially available topical antimicrobial products against control strains and those from clinical material are compared with an agar diffusion model. The MICs of the constituent antimicrobial compounds have been determined for the same organisms. Plotting the inhibition zone diameters produced by the topical products against the log10 MICs of their constituent antimicrobial compound(s) gives overall product performance profiles for a range of organisms. These profiles confirm that the formulation of a topical product clearly modifies the response obtained with a specific antimicrobial compound.

Administration, Topical↗
PubMed1989

Examination of mucosal surfaces by scanning electron microscopy before and after removal of debris.

A rapid method is described whereby gastrointestinal biopsy specimen surfaces can be examined by scanning electron microscopy with overlying tract contents (debris) intact, and also re-examined after cleaning to determine the structure of the underlying mucosal surface. The conductive coating of gold is removed using mercury, a non-wetting agent. The specimen surface is suitably cleaned of debris after a brief ultrasonication in absolute ethanol which mixes with the transitional fluid (CO2) used for critical point drying.

Animals↗
PubMed1989

Stability of murine monoclonal anti-A, anti-B and anti-A,B ABO grouping reagents and a multi-centre evaluation of their performance in routine use.

We have previously reported the production of 3 murine monoclonal reagents for ABO typing (designated ES-9, ES-4 and ES-15). This study presents results of tests of stability of these 3 reagents, together with a fourth murine monoclonal antibody (LM103/107). In addition, data are also presented from a multi-centre evaluation of the performance of the murine monoclonal reagents in routine ABO typing of both donors and patients using a wide variety of techniques, both manual and automated. The potency and stability of the 4 monoclonal antibody based reagents is compared with a broad selection of monoclonal and polyclonal ABO typing reagents. The reagents used for comparison were produced by European and United States manufacturers in both the public and private sector and are widely used in routine ABO typing. The Scottish monoclonal reagents have been used successfully to ABO type over 500,000 blood samples in 7 centres within the UK, with no discrepant results.

ABO Blood-Group System↗
PubMed1989

Polyethylene glycol in the production of blood grouping reagents: some further advantages.

The use of various water-soluble non-ionic polymers, including polyethylene glycol (PEG) 8000, has been described in the preparation of diagnostic blood grouping reagents. The major advantages of using PEG in this way are ease of preparation and the ability to concentrate antibodies. We describe here two previously unreported advantages of using PEG: (i) substantial reductions in the volume of red cells required for adsorption of isoagglutinins; and (ii) the ability to store PEG precipitates in a 'dry' form substantially reduces storage requirements.

Blood Grouping and Crossmatching↗
PubMed1988

Fatal respiratory disease in Nilgiri tahr: possibly malignant catarrhal fever.

Nilgiri tahr (Hemitragus hylocrius) are native to India and are a rare zoo exhibit. This report describes an acute respiratory disease in tahr that caused the death of 15 of 16 animals in an extensive exhibit of about 35 acres where they were housed together with a variety of other exotic species of ruminants. The deaths occurred in two separate outbreaks and were associated with losses from malignant catarrhal fever in other ruminants in the exhibit. The most prominent clinical sign was severe dyspnea, and death occurred within five days. The principal lesions were an acute nonsuppurative inflammation of the respiratory tract and pulmonary vessels, lymphadenopathy and lymphoid cell infiltration in the organs of some animals. It was conjectured that the tahr died of a unique pneumonic form of malignant catarrhal fever. Attempts at viral isolation were negative.

Animals↗
PubMed1980

Mortality in little penguins (Eudyptula minor) along the coast of Victoria, Australia.

Forty-eight little penguins (Eudyptula minor) consisting of 21 (43.7%) mature, 18 (37.5%) juvenile and nine (18.7%) of undetermined age, from 10 Victorian coastal localities were examined during 1977-78. Thirty-seven (77%) of all penguins were in poor body condition with moderate to heavy burdens of internal and external parasites. Acute parasitic gastric ulceration with accompanying hemorrhage, was implicated in the death of four birds. Chronic gastric ulcers were thought to have caused appetite depression and starvation in 28 birds. Other significant lesions encountered included renal coccidiosis, parasitic cholangiohepatitis and pulmonary aspergillosis. It is suggested that the increased mortality experienced during 1977-78 was due to starvation or to exacerbation of the effects of existing parasite burdens on starving and exhausted birds.

Animals↗