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Biomedical subjects

A J Wright

Publications and source records attributed to A J Wright.

At least 73 records · Page 4Linked to original sources
PubMed1994

Thiamin intake, erythrocyte transketolase (EC 2.2.1.1) activity and total erythrocyte thiamin in adolescents.

The relationships between thiamin intake, erythrocyte transketolase (EC 2.2.1.1) activity coefficient (ETK-AC) and total erythrocyte thiamin were investigated in a group of adolescents (13 to 14 years old; nineteen boys, thirty-five girls). Thiamin intakes were calculated from 7 d weighed records, using food composition tables, and compared with those obtained by direct analysis of duplicate diets. Average 7 d calculated thiamin intakes were significantly lower than analysed intakes for both sexes. On an individual basis, calculated intakes ranged from 30 to 143% of corresponding analysed values. Analysed and calculated intakes were significantly correlated when expressed as mg/d; however, when expressed in terms of energy intake, the correlation was significant for males only. Thiamin intake appeared largely adequate when compared with current UK dietary recommendations (Department of Health, 1991), but the limitations of such comparisons are considered. The major food groups contributing to thiamin intake were examined and showed breakfast cereals to contribute more than 25% of dietary thiamin. A proportion of the subjects had ETK-AC values in ranges usually associated with marginal or severe thiamin deficiency. There was, however, no statistically significant relationship between erythrocyte thiamin and basal or stimulated transketolase activity, or between thiamin intake and either of the methods used to assess status. The need to re-evaluate indices of thiamin status is discussed.

Adolescent↗
PubMed1994

Dietary intake and micronutrient status of adolescents: effect of vitamin and trace element supplementation on indices of status and performance in tests of verbal and non-verbal intelligence.

Relationships between micronutrient intake and status, and micronutrient status and performance in tests of intelligence were investigated in a group of adolescents (13-14 years old). Dietary intakes were assessed using a 7 d weighed dietary record method, coupled with the collection of duplicate diets. Vitamin and trace mineral intakes calculated using food composition tables were compared with those obtained by direct analysis of duplicate diets. Micronutrient status was judged via a range of biochemical indices measured in blood samples taken after a 12-15 h fast. Blood samples were taken both before and after a 16-week period of vitamin and trace mineral supplementation. Individual tests of verbal and nonverbal intelligence were also performed pre- and post-supplementation. The results of this study indicate that the use of food table data may lead to substantial over- or underestimation of the intake of several micronutrients. In general, the total calculated or analysed amount of a specific micronutrient consumed did not adequately predict status, as judged by a range of biochemical indices. There were significant changes in status measurements over the 16-week study period, irrespective of supplementation, and these changes were markedly influenced by the initial status of the subject. There was no effect of supplementation on performance in tests of intelligence. However, there was a significant association between plasma ascorbic acid and initial non-verbal intelligence quotient (IQ) in the boys, and between whole blood glutathione peroxidase (EC 1.11.1.9) activity and non-verbal and verbal IQ in both sexes. These findings are discussed in relation to other recent studies of the influence of micronutrient supplementation on the psychological performance of children.

Adolescent↗
PubMed1993

The effect of dietary calcium intake in weanling rats on the efficiency of calcium absorption.

Rats were weaned onto high (HCa, 14.6 g/kg)- or low (LCa, 3.88 g/kg)-Ca diets for 12 d and the efficiency of absorption of Ca measured from 20 mg Ca (as CaCl2, labelled with 47Ca) by means of whole-body counting. The LCa group absorbed 74% of the test dose and the HCa group 60% of the test dose (P < 0.001). All animals were then given the LCa diet for 6 weeks and the absorption test repeated. This time there was no difference in efficiency of absorption (HCa 54%, LCa 57%). The femur dry weight was significantly lower in the group initially fed on the LCa diet, but the Ca concentration was similar to that of the HCa group. The results do not lend support to the suggestion that early dietary exposure to Ca manifests itself as a difference in Ca metabolism in later life. They do, however, highlight the importance of adequate Ca intake during critical periods of growth.

Animals↗
PubMed1993

Vitamin C intake and plasma ascorbic acid concentration in adolescents.

The relationship between vitamin C intake and status was investigated in a group of adolescents (13-14 years old). Dietary intakes were assessed using a 7 d weighted dietary record method, coupled with the collection of duplicate diets. Vitamin C intakes calculated using food composition tables were compared with values obtained by direct analysis of duplicate diets. Vitamin C status was judged via measurement of plasma ascorbic acid (AA) concentration in blood samples taken after a 12-15 h fast. The relationship between calculated and analysed vitamin C intake and plasma AA concentration was examined. Average daily calculated vitamin C intakes, for the group (n 54) as a whole over a 7 d period, gave a good estimate of intake, as judged by prompt analysis of duplicate diets. However, analysed v. calculated intakes were significantly different for approximately one-third of subjects when data were examined on an individual basis. Large discrepancies between analysed and calculated values could not be accounted for on a food group basis. In all but two individuals, calculated vitamin C intake was in excess of the new reference nutrient intake (RNI, part of the new daily reference values (Department of Health and Social Security, 1991)) of 40 mg and all plasma AA concentrations were well above those used to indicate even a moderate risk of deficiency. A relationship between vitamin C intake and plasma AA was observed for both males (n 19) and females (n 35). However, the relationship was much stronger for males who showed a wider range of both intake and plasma AA values.

Adolescent↗
PubMed1993

New home care choices for children with special needs.

Ten years ago, children with complex medical conditions remained hospitalized; five years ago they could choose from hospital or home care. Now families and professionals caring for children with complex conditions have many choices regarding the best setting for their child's care.

Child↗
PubMed1993

Testosterone pellet implant therapy for lichen sclerosus.

Lichen sclerosus is a benign chronic skin disease predominantly affecting the vulva in post-menopausal women. Various methods of therapy have been recommended for this stubborn and uncomfortable condition. The article describes a new method of therapy for patients suffering from this disorder, utilizing subcutaneously-implanted testosterone pellets to obtain extended remission of symptoms.

Drug Implants↗
PubMed1992

Clinical utility of bronchoalveolar lavage in immunocompromised hosts.

Bronchoalveolar lavage (BAL) has been used extensively for assessment of immunocompromised hosts with pulmonary infiltrates. Reported estimates of the diagnostic utility of BAL have varied because of differences in patient populations, diagnostic criteria, and study methods. Herein we report on the use of BAL to determine at least one of the final diagnoses in 150 immunocompromised patients. Although the frequency with which BAL provided at least one of the final diagnoses (overall diagnostic yield) was seemingly low (39%), the yield increased substantially when only patients with pathologically proven diagnoses were considered. The sensitivity of BAL was 82%, and the specificity was 53%. The use of rigid diagnostic criteria enabled us to distinguish pathogens from colonizers. Pneumocystis was considered a pathogen whenever it was identified. It was the most common infectious pathogen identified (50%) despite the fact that our study population had relatively few patients (only 4%) with acquired immunodeficiency syndrome (AIDS). Organisms such as cytomegalovirus, Aspergillus, and Candida were frequently identified in BAL specimens but were eventually proved to be pathogens in only 24%, 25%, and 0% of cases, respectively. BAL detected pulmonary malignant lesions on the basis of positive cytologic results in four of six patients eventually found to have primary or metastatic lung cancer. Our results should enhance the understanding of the strengths and weaknesses of BAL and assist in the interpretation of associated microbiologic findings.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Dietary fat intake and plasma lipid levels in adolescents.

The relationship between dietary fat intake and fasting plasma lipid levels was assessed in 35 female and 19 male adolescents recruited from two local education authority schools in Norwich, UK. Dietary intakes were assessed using a 7-day weighed dietary record method, coupled with the collection of duplicate diets. Fat and energy intakes calculated using food composition tables were compared with values obtained by direct analysis of duplicate diets. Fasting plasma lipid levels (total, HDL and LDL cholesterol and triglycerides) were measured and compared with total dietary lipids and fatty acid intakes. The average proportion of energy consumed as fat was higher than is currently considered desirable but lower than previous studies have reported for adults. Mean serum total cholesterol values were 4.2 (SEM 0.1) mmol for females and 4.5 (SEM 0.2) mmol for males; this difference was not statistically significant. In male subjects the dietary fatty acid profiles were significantly correlated with several parameters of plasma lipid status which are thought to be risk factors for coronary heart disease, and in particular with the ratio of total:HDL cholesterol.

Adolescent↗
PubMed1991

The penicillins.

The penicillin family of antibiotics remains an important part of our antimicrobial armamentarium. In general, these agents have bactericidal activity, excellent distribution throughout the body, low toxicity, and efficacy against infections caused by susceptible bacteria. The initial introduction of aqueous penicillin G for treatment of streptococcal and staphylococcal infections was an important pharmacologic landmark. The emergence of penicillinase-producing Staphylococcus aureus prompted the development of the penicillinase-resistant penicillins (for example, methicillin, oxacillin, and nafcillin), in which an acyl side chain prevented disruption of the beta-lactam [corrected] ring. Subsequently, the aminopenicillins (such as ampicillin and amoxicillin) were developed because of the need for gram-negative antimicrobial activity. Their spectrum included Escherichia coli, Proteus mirabilis, Shigella Salmonella, Listeria, Haemophilus, and Neisseria. The search for a penicillin with additional antimicrobial activity against the Enterobacteriaceae and Pseudomonas aeruginosa led to the development of the carboxypenicillins (carbenicillin, ticarcillin, and temocillin) and the ureidopenicillins (mezlocillin, azlocillin, piperacillin, and apalcillin). Finally, the combination of a beta-lactamase inhibitor (clavulanic acid or sulbactam) and an aminopenicillin or ticarcillin has further extended their antibacterial spectra. The development of an ideal penicillin that is rapidly bactericidal, nonsensitizing, nontoxic, bioavailable, resistant to beta-lactamase, and without inoculum effect and that has a high affinity for penicillin-binding proteins remains the goal.

Humans↗
PubMed1991

The fluoroquinolones.

The fluoroquinolone class of antibiotics promises to become as diverse and as important as beta-lactam agents. The fluoroquinolones inhibit bacterial DNA gyrase and are bactericidal. All fluoroquinolones have potent activity against most gram-negative bacteria; ciprofloxacin is the most active against Pseudomonas aeruginosa. Activity against gram-positive organisms is variable; methicillin-resistant Staphylococcus aureus has acquired resistance to the fluoroquinolones at an alarming rate. Currently available quinolones do not have, but new quinolone agents likely will have, substantial activity against anaerobic bacteria. Some quinolones are also active against Mycobacterium, Chlamydia, and Mycoplasma organisms. All fluoroquinolones have excellent absorption after oral administration; however, this process can be impaired by the presence of aluminum- or magnesium-containing antacids and by zinc, iron, or calcium supplements. Ciprofloxacin is also available for intravenous use. Although most fluoroquinolones do not achieve adequate cerebrospinal fluid levels, penetration into other tissues is excellent. Dosage adjustments for renal and hepatic dysfunction vary among the quinolones. Although side effects are rare, concomitant use of caffeine or theophylline with some quinolones may cause toxicity to the central nervous system. Because they may affect the development of cartilage, all fluoroquinolones are contraindicated in children, adolescents, and pregnant or breast-feeding women.

4-Quinolones↗
PubMed1991

Riboflavin deficiency in the rat: effects on iron utilization and loss.

Iron absorption and daily loss of Fe were measured in riboflavin-deficient (B2-) Norwegian hooded rats and controls (B2+). Animals were fed on a test meal extrinsically labelled with 59Fe and whole-body radioactivity measured for 15 d. Riboflavin deficiency led to a reduction in the percentage of the 59Fe dose absorbed and an increased rate of 59Fe loss. All post-absorption 59Fe loss could be accounted for by faecal 59Fe, confirming that the loss was gastrointestinal. Fe concentrations and 59Fe as a percentage of retained whole-body 59Fe were higher in the small intestine of riboflavin-deficient animals than their controls, 14 d after the test meal. A separate experiment demonstrated that riboflavin deficiency was associated with a significant proliferative response of the duodenal crypts of the small intestine. These observations may explain the enhanced Fe loss in riboflavin deficiency.

Absorption↗