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Biomedical subjects

A J Wright

Publications and source records attributed to A J Wright.

At least 55 records · Page 3Linked to original sources
PubMed1997

The effect of beta-carotene supplementation on the immune function of blood monocytes from healthy male nonsmokers.

Although there is strong epidemiologic evidence that diets rich in carotenoids such as beta-carotene are associated with a reduced incidence of cancer, the cellular mechanisms underlying this phenomenon remain unknown. This article describes the effect of dietary beta-carotene supplementation on both the expression of functionally associated surface molecules on human monocytes and on the secretion of the cytokine tumor necrosis factor-alpha (TNF-alpha) by monocytes, all of which are involved in the initiation and regulation of immune responses involved in tumor surveillance. A double-blind, placebo-controlled, crossover study was undertaken in which 25 healthy, adult male nonsmokers were randomly assigned to receive beta-carotene (15 mg daily) or placebo for 26 days, followed by the alternative treatment for a further 26 days. The expression of functionally related monocyte surface molecules was quantified by flow cytometry, and ex vivo secretion of TNF-alpha was quantified by an enzyme-linked immunosorbent assay, before and after each treatment period. After dietary supplementation there were significant increases in plasma levels of beta-carotene and in the percentages of monocytes expressing the major histocompatibility complex class II molecule HLA-DR and the adhesion molecules intercellular adhesion molecule-1 and leukocyte function-associated antigen-3. In addition, the ex vivo TNF-alpha secretion by blood monocytes was significantly increased after supplementation. These findings suggest that moderate increases in the dietary intake of beta-carotene can enhance cell-mediated immune responses within a relatively short period of time, providing a potential mechanism for the anticarcinogenic properties attributed to beta-carotene.

Adult↗
PubMed1997

Relationships between micronutrient intake and biochemical indicators of nutrient adequacy in a "free-living' elderly UK population.

Nutritional assessments are frequently based on amounts of nutrients consumed. In the present paper the usefulness of nutrient intake data for assessing nutrient adequacy is examined in an elderly British population. Subjects were "free-living' elderly aged 68-90 years (sixty men, eighty-five women) in Norwich. Forty-two of forty-nine surviving males and sixty-seven of seventy-nine surviving females were reassessed after 2 years. With few exceptions, estimated micronutrient intake was not statistically predictive of biochemical measures of nutrient adequacy. Initial biochemical measures of nutritional adequacy were compared with those found 2 years later in an attempt to assess whether initial biochemical assessment was predictive of the "longer term' situation. Biochemical measurements at the start of the study were correlated to the same measurements made 2 years later for: serum ferritin, haemoglobin and erythrocyte count, whole-blood Se-glutathione peroxidase (EC 1.11.1.9; males only), plasma Cu, alkaline phosphatase (EC 3.1.3.1), ascorbic acid, vitamin B6 (pyridoxal-5-phosphate), folate and vitamin B12, total erythrocyte thiamin (males only), riboflavin (erythrocyte glutathione reductase (EC 1.6.4.1) activation coefficient): but not for: erythrocyte Cu-superoxide dismutase (EC 1.15.1.1) or plasma Zn. Either only small changes, or no changes, in mean values were seen over the 2 years for most of the biochemical measures. One exception was a large increase in plasma folate. The only important "negative' features seen at 2-year follow up were a large fall in serum ferritin concentration and a large increase in the activity of two antioxidant defence enzymes, superoxide dismutase and glutathione peroxidase. As judged by currently accepted biochemical deficiency threshold values, a small proportion of subjects were possibly at risk of Fe (3% men; 1% women), folate (7%, 3%), thiamin (12%; 3%) and vitamin C (15%; 17%) deficiency. Many more appeared to be at risk of vitamin B6 (42%; 47%) and riboflavin (77%; 79%) deficiency. It was concluded that the requirements of the elderly for vitamins B1, B2 and C, and the biochemical deficiency threshold values used to indicate vitamin B6 deficiency, need review.

Aged↗
PubMed1997

Recent advances in the management of human immunodeficiency virus infection.

Major advances during the past 2 years have resulted in an unprecedented optimism regarding the perception of human immunodeficiency virus (HIV) infection. An improved understanding of the pathogenesis of HIV infection coupled with the availability of assays to measure HIV-1 RNA and the approval of new antiretroviral drugs has led to the development of new approaches to the management of HIV infection. In this article, we discuss these advances and their implications in the care of HIV-infected patients. In addition, we present the guidelines for the use of antiretroviral therapy for HIV infection.

Anti-HIV Agents↗
PubMed1996

High levels of genetic change in rodents of Chernobyl.

Base-pair substitution rates for the mitochondrial cytochrome beta gene of free-living, native populations of voles collected next to reactor 4 at Chernobyl, Ukraine, were estimated by two independent methods to be in excess of 10(-4) nucleotides per site per generation. These estimates are hundreds of times greater than those typically found in mitochondria of vertebrates, suggesting that the environment resulting from this nuclear power plant disaster is having a measurable genetic impact on the organisms of that region. Despite these DNA changes, vole populations thrive and reproduce in the radioactive regions around the Chernobyl reactor.

Animals↗
PubMed1996

Cure of a solitary brainstem abscess with antibiotic therapy: case report.

A solitary brainstem abscess is uncommon. The use of antibiotics and surgical aspiration or excision of a brainstem abscess has resulted in survivors. Survival after treatment of a brainstem abscess with antibiotics alone has been reported rarely, and we present the eighth study case. The patient made an excellent recovery after 12 weeks of antibiotics, with 8 weeks completed as an outpatient. Medical management of a solitary brainstem abscess in an immunocompetent patient is feasible and may result in a complete cure with antibiotics only. Completion of IV antibiotics as an outpatient is viable and cost-effective in selected patients.

Anti-Infective Agents↗
PubMed1996

SLE nephropathy in a patient with HIV infection: case report and review of the literature.

We describe a 39-year-old bisexual man with clinical category B2 human immunodeficiency virus (HIV) infection who subsequently developed systemic lupus erythematosus (SLE). SLE was diagnosed on the basis of a clinical presentation of malar rash, polyarthritis, membranous glomerulonephritis, and characteristic serology. To our knowledge, this is the fourth reported case of a patient with HIV infection to develop SLE and the second adult patient with HIV and coexistent SLE nephropathy.

Adult↗
PubMed1995

Davy comes to America: Woodhouse, Barton, and the nitrous oxide crossing.

In the final decade of the eighteenth century, a new method of medical treatment appeared in England when physician Thomas Beddoes developed a systematic application of Joseph Priestley's "factitious airs", or gases, to treat consumptive patients. Supported by peers such as Erasmus Darwin and using applications designed for him by James Watt and other inventors, Beddoes combined technological innovation and gas inhalation in an attempt to cure his patients. Late in the decade Beddoes hired young Humphry Davy as his assistant; Davy quickly added nitrous oxide to the armamentarium. The prominent group Davy assembled to help him test nitrous oxide and record their experiences has seldom been equaled in medical history as a research population. Davy left the Pneumatic Institution in March 1801 and joined the staff of the infant Royal Institution in London, but news of the nitrous oxide soon reached American. Physician James Woodhouse, a professor of chemistry at the University of Pennsylvania since July 1795, left in early 1802 for England, where he met Davy. A few years later one of his chemistry students preserved an account of the extensive nitrous oxide trials that took place in Woodhouse's classroom throughout 1807. In that work William Barton discussed and replicates Davy's research and agrees with his conclusions. Such intermittent experimentation continued in the United States and Europe until Horace Well's public demonstration of ether inhalation in January 1845. This paper describes how nitrous oxide inhalation survived in America through the work of Woodhouse and Wells. Traveling showmen like Samuel Colt and Gardner Quincy Colton demonstrated the gas' effects at popular lectures.(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesiology↗
PubMed1995

Nutrient intake and biochemical status of non-instutionalized elderly subjects in Norwich: comparison with younger adults and adolescents from the same general community.

The Department of Health (1992) has recently stated that 'Nutritional reviews concerning elderly people are especially constrained by lack of data', and that much of the emphasis in the nutritional literature has been placed on the study of institutionalized, and often chronically ill, elderly subjects rather than the non-institutionalized elderly who form the majority of this population. The present study presents information on the dietary intake and biochemical status of non-institutionalized elderly subjects (68-73 and 74-90 years) and compares such data with those obtained for adult (20-64 years) and adolescent (13-14 years) populations living within the same community. Nutrient intakes and appropriate biochemical measurements of nutrient status, performed on fasting blood samples, were statistically examined and have been discussed in relation to potential age-related influences. The nutrient intake of elderly subjects was on a par with adolescents of corresponding sex but generally lower than that of adult counterparts. There were several significant differences in biochemical measurements of nutrient status between age groups. In general these did not suggest progressive age-related trends. However, there were significant suggestions of age-related increases in whole-blood glutathione peroxidase (EC 1.11.1.9) activity, serum ferritin, plasma cholesterol, LDL and triacylglycerol concentrations and decreases in plasma HDL and ascorbic acid concentrations. The significance of these differences is discussed. An age-related difference (suggestive of a decline) in vitamin C status together with a difference (suggestive of an increase) in glutathione peroxidase activity may indicate an imbalance in the regulation of O2-derived free-radicals with ageing. These observations are worthy of a further study in the light of current thinking which relates the induction of a number of diseases to oxidative damage.

Adolescent↗
PubMed1995

The influence of supplemental chromium and vaccines on the acute phase response of newly arrived feeder calves.

The acute phase response as indicated by serum haptoglobin and total haemolytic complement activity (CH50) was measured in 72 cross-bred steer calves purchased at sales in Ontario. During the 28 day (d) trial, 18 steers were randomly assigned to each of the following groups: 1) control; 2) vaccinated (Infectious Bovine Rhinotracheitis, Parainfluenza-3, Bovine Viral Diarrhea, Bovine Respiratory Synctial Virus vaccine plus Pasteurella haemolytica vaccine); 3) supplemental chelated Cr (0.14 mg/kg); and 4) Cr plus vaccines. Haptoglobin concentrations were low at arrival, increased (P < 0.05) on day 7, and returned to near initial levels (P > 0.05) by day 14. Supplemental Cr reduced (P < 0.05) haptoglobin on day 7 when morbidity was highest. Following antibiotic treatment for respiratory disease haptoglobin was lower (P < 0.05) than during morbidity; however, during morbidity, haptoglobin concentrations were not greater in sick calves (P > 0.05) than in healthy calves. Complement activity was lowest on day 7 (P < 0.05) and peaked on day 14 (P < 0.05). Complement activity tended to be lower on day 7 for vaccine, Cr, and Cr+ vaccine groups; however, the difference from controls was not significant (P > 0.10). Complement activity did not increase on day 14 (P > 0.05) with Cr supplementation as in other treatments. Morbid calves had lower (P < 0.05) CH50 activity than healthy calves on day 14. Following antibiotic treatment, the Cr-supplemented group had higher (P < 0.05) CH50 than during morbidity. In general, chromium supplementation reduced the acute phase response in newly arrived feeder calves.

Acute-Phase Reaction↗