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Biomedical subjects

M G Wright

Publications and source records attributed to M G Wright.

At least 19 recordsLinked to original sources
PubMed2005

Effect of 902 MHz mobile phone transmission on cognitive function in children.

We examine whether a standard mobile exposure at 902 MHz has a significant effect on cognitive function in 18 children 10-12 years of age. These were in a single group in which each child was given a single training session and then three test sessions in a randomized, three-way crossover design, using the cognitive drug research (CDR) cognitive assessment system. Exposures were 0, 0.025, or 0.25 W from a standard Nokia 3110 mobile phone handset mounted on a plastic headset in normal use position. The results of testing showed that the baseline (0 W) performance for the reaction time measurements was considerably slower than for the comparable measures in adult. There was a tendency for reaction time to be shorter during exposure to radiation than in the sham (baseline) condition, an effect that was most marked for simple reaction time. However, no effects reached statistical significance after Bonferroni correction. Therefore, we conclude that this study on 18 children did not replicate our earlier finding in adults that exposure to microwave radiation was associated with a reduction in reaction time. It should be noted that the present study investigated the effects of radiation from a GSM handset, whereas in our previous study the effect on reaction time was observed only with a more powerful analogue handset.

Body Burden↗
PubMed1995

[A common language for nurses: a persistent dilemma].

The author during her discussion tries to explain that the theme needs another approaching perspective. Therefore, she uses a critical model to find out the ideology of the theme; the factors that have contributed to the dilemma inside and outside the profession; presents a general view of the situation in Latin America and finalizes the paper with the indication of some actions aiming at transforming Nursing and enabling the discussion and work with this theme.

Communication Barriers↗
PubMed1992

Human monoclonal antibodies specific for blood group antigens demonstrate multispecific properties characteristic of natural autoantibodies.

A panel of 72 human monoclonal antibodies with specificities for blood group antigens, A, Rh D, Rh C, Rh c, Rh E, Rh e, Rh G, Jka and Jkb, has been established from the peripheral blood of deliberately immunized donors. Previous work has established that the antibodies are highly specific for their respective blood group antigens, and a number of them are in routine clinical use as blood grouping reagents. This panel was screened for reactivity against six unrelated foreign and autoantigens by ELISA, for rheumatoid factor activity by ELISA and agglutination techniques, and for reactivity with a number of different tissues by immunofluorescence. Binding of the monoclonal antibodies to unrelated exo- and autoantigens was commonly seen amongst the antibodies of the IgM class, and to a lesser degree amongst the IgG class, with reaction patterns similar to those given by natural autoantibodies. Only five of the IgM antibodies failed to demonstrate any unexpected cross-reactivities and these included 1/13 anti-D, 2/7 anti-E, 1/13 anti-c and 1/2 anti-A. We propose that rather than natural autoantibodies representing a distinct population of immunoglobulins, multispecificity (polyspecificity, or polyreactivity) may be a feature of antibodies produced in response to exogenous antigens. The implications of this for the study of autoantibodies are discussed.

Antibodies, Monoclonal↗
PubMed1987

The assessment of chemically induced liver injury in rats.

The object of this investigation was to study the relationship between acute hepatic injury and blood coagulation. Most of the clotting factors are synthesised by the hepatocytes and therefore it would seem likely that hepatic injury would lead to an impairment of blood clotting. Dimethylnitrosamine (DMN) and carbon tetrachloride (CCl4) were selected as model hepatotoxins to induce an acute hepatic lesion. Single doses of each compound were administered to male rats and groups of animals killed 3, 6, 16 and 24 h later in order to study the morphological development of the lesion and to relate this to changes in the haematological profiles. Both compounds produced a centrilobular necrosis, but with DMN there was a haemorrhagic component due to damage to endothelial cells, which contrasts with the classical coagulative necrosis produced by CCl4. After 6 h apoptosis was commonly seen in the centrilobular areas of the DMN treated rats. This process of cell death has not previously been demonstrated in chemically induced acute hepatic injury and was not seen in the CCl4 treated rats. Significantly prolonged clotting times were seen in both DMN and CCl4 treated rats and occurred in parallel with some of the early morphological changes but prior to the appearance of extensive haemorrhagic or coagulative necrosis. This preliminary data suggests that the measurement of blood coagulation times may provide a relatively specific and sensitive indicator of acute hepatic injury in rats.

Animals↗
PubMed1987

Long-term toxicity study of Ponceau 4R in rats using animals exposed in utero.

Groups of 66 (treated) or 114 (control) rats of each sex were fed diets providing 0 (control), 50, 500 or 1250 mg Ponceau 4R/kg body weight/day for 60 days. The animals were then mated and allowed to rear their litters. At weaning, pups were selected for the long-term study to give treated groups of 54 (of each sex) and a control group of 96 (of each sex), with offspring always receiving the same treatment as their parents. Treatment continued until approximately 20% of animals survived, resulting in a duration of 114 wk for males and 118 wk for females. Body weight, food and water intake and clinical conditions were monitored regularly throughout the study. Blood and urine from 20 rats/sex/group from the high-dose and control groups were examined at months 3, 6, 12, 18 and 24. At the end of the study each animal was autopsied, selected organs were weighed, and a full range of tissues was preserved. High-dose animals showed a lower body-weight gain without any reduction in food intake. Water intake was higher than that of the controls in the medium- and high-dose groups and this was related to caecal enlargement and softening of faeces. No adverse changes were seen in the investigations of blood or urine apart from a higher incidence of females with higher levels of protein in urine at the 1250 mg/kg/day dose. No other findings of significance were seen and survival and tumour incidence were similar in all groups. A no-untoward-effect level was established at 500 mg Ponceau 4R/kg/day.

Animals↗
PubMed1983

Short-term toxicity of 2,6-dimethylhept-5-en-1-al in rats.

Groups of 15 male and 15 female rats were fed for at least 90 days on diets that provided 2,6-dimethylhept-5-en-1-al (DMH) at average intakes of 0 (control), 9, 37 and 150 mg/kg body weight/day. Steps were taken to limit loss of DMH during diet mixing, storage and feeding. No effects attributable to treatment were encountered in body weight, food intake, water intake, haematology (at wk 6 and 13) or the gross and microscopic pathological examinations. At the highest dose level there was a slight reduction in renal concentrating ability at wk 6 in males and wk 14 in females, together with a small increase in relative kidney weight and liver weight in females. The serum-glucose concentrations of both sexes on the highest dose were elevated compared with the controls. It was concluded that the intermediate dose, providing an intake of 37 mg/kg/day, was the no-untoward-effect level.

Aldehydes↗
PubMed1982

Short-term toxicity of 2-phenylpropan-1-ol (hydratropic alcohol) in rats.

Phenylpropan-1-ol was added to the diet of groups of 15 male and 15 female rats to provide intakes of 0 (control), 10, 40 or 160 mg/kg/day for 13 wk. No effects on body weight, food intake, water intake, haematology, semi-quantitative analysis of urine, renal concentration and dilution tests, serum chemistry or the histological examination could be attributed to treatment. Increased liver weights at the highest dose level in both sexes and increased kidney weights at the two highest dose levels in males were considered to be related to treatment, but in view of the lack of histological abnormalities this study did not demonstrate whether these were toxic or adaptive effects. An isolated renal mesenchymal tumour was found in the females fed the highest dose level. It is concluded that the no-effect level in this study was 10 mg/kg/day.

1-Propanol↗
PubMed1981

The influence of folic acid on the frequency of epileptic attacks.

A double blind trial of folic acid against placebo was carried out on out-patients with epilepsy treated with Phenytoin. There was a minimum period on treatment of one year. While the group receiving folic acid in the treatment period showed a significant improvement in seizure frequency, the placebo group also showed some improvement. It is concluded that the improvement while on folic acid was not due to the folic acid treatment alone. The subjective well-being of patients was not influenced by folic acid therapy.

Adult↗
PubMed1978

Postmeningitic hydrocephalus in infancy. Ventriculography with special reference to ventricular septa.

Postmeningitic hydrocephalus in infancy accounts for at least 30% (maybe even 40%) of all new paediatric hydrocephalics seen in the Cape Province. The causes of the marked racial preponderance are considered. Meningitis is more prone to cause a CSF pathway block at any site in infancy than later in life. On ventriculography ventricular septa in 23%, foramen of Monro obstruction in 13%, multiple CSF pathway block occasionally and intraventricular detritus causing filling defects and irregularities of the ventricular walls are the salient features. Birth trauma with intraventricular bleeding may on occasion cause similar changes.

Age Factors↗
PubMed1978

Local anaesthetic nerve block in the treatment of intractable pain from osteoarthritis of the hip.

Previous workers have advocated hip nerve block, with local anaesthetic, in the treatment of intractable pain from osteoarthritis of the hip. In a pilot study we obtained some degree of pain relief in only six of 13 patients. A further double-blind, controlled, randomized trial was undertaken in 31 patients, comparing 0.5% Marcain and normal saline. There was no significant improvement in pain or hip movements in either group over a six-week period.

Aged↗
PubMed1976

Micro-encapsulated aspirin (Levius) compared with aloxiprin (Palaprin Forte) in the treatment of rheumatoid arthritis.

A randomized crossover trial of micro-encapsulated aspirin (Levius) and aloxiprin (Palaprin Forte) was carried out on thirty-three hospital outpatients with rheumatoid arthritis. Both preparations improved the clincial status of the patients. The difference in response to the two preparations was not significant, except for effect on functional status where the micro-encapsulated aspirin was found to be significantly better at the 5% level. Apart from six complaints of constipation with aloxiprin compared with only one with Levius, the side-effects were similar. The trial has shown that Levius can be conveniently given in divided doses thrice daily without loss of efficacy.

Aged↗