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Biomedical subjects

L Maynard

Publications and source records attributed to L Maynard.

8 recordsLinked to original sources
PubMed2003

Treatment of canine parvoviral enteritis with interferon-omega in a placebo-controlled field trial.

The clinical efficacy of a recombinant feline interferon (IFN) (type omega) was evaluated under field conditions for the treatment of dogs with parvoviral enteritis. In this multicentric, double-blind, placebo-controlled trial, 94 dogs from one to 28 months old were randomly assigned to two groups which were treated intravenously either with IFN (2.5 million units/kg) or placebo once a day for three consecutive days, and monitored for clinical signs and mortality for 10 days. Each dog received individual supportive treatment The data from 92 interpretable cases (43 IFN-treated and 49 placebo) showed that the clinical signs of the IFN-treated animals improved significantly in comparison with the control animals, and that there were only three deaths in the IFN group compared with 14 deaths in the placebo group (P = 0.0096) corresponding to a 4.4-fold reduction. Alternative analyses of the data taking into account the prior vaccination status of the dogs against canine parvovirus suggested that the IFN therapy resulted in a 6.4-fold reduction in mortality (P = 0.044) in the unvaccinated cohort, a significant reduction when compared with the vaccinated cohort.

Animals↗
PubMed2001

Therapeutic doses of oral methylphenidate significantly increase extracellular dopamine in the human brain.

Methylphenidate (Ritalin) is the most commonly prescribed psychoactive drug in children for the treatment of attention deficit hyperactivity disorder (ADHD), yet the mechanisms responsible for its therapeutic effects are poorly understood. Whereas methylphenidate blocks the dopamine transporter (main mechanism for removal of extracellular dopamine), it is unclear whether at doses used therapeutically it significantly changes extracellular dopamine (DA) concentration. Here we used positron emission tomography and [(11)C]raclopride (D2 receptor radioligand that competes with endogenous DA for binding to the receptor) to evaluate whether oral methylphenidate changes extracellular DA in the human brain in 11 healthy controls. We showed that oral methylphenidate (average dose 0.8 +/- 0.11 mg/kg) significantly increased extracellular DA in brain, as evidenced by a significant reduction in B(max)/K(d) (measure of D2 receptor availability) in striatum (20 +/- 12%; p < 0.0005). These results provide direct evidence that oral methylphenidate at doses within the therapeutic range significantly increases extracellular DA in human brain. This result coupled with recent findings of increased dopamine transporters in ADHD patients (which is expected to result in reductions in extracellular DA) provides a mechanistic framework for the therapeutic efficacy of methylphenidate. The increase in DA caused by the blockade of dopamine transporters by methylphenidate predominantly reflects an amplification of spontaneously released DA, which in turn is responsive to environmental stimulation. Because DA decreases background firing rates and increases signal-to-noise in target neurons, we postulate that the amplification of weak DA signals in subjects with ADHD by methylphenidate would enhance task-specific signaling, improving attention and decreasing distractibility. Alternatively methylphenidate-induced increases in DA, a neurotransmitter involved with motivation and reward, could enhance the salience of the task facilitating the "interest that it elicits" and thus improving performance.

Administration, Oral↗
PubMed2001

Field efficacy of a 10 per cent pyriproxyfen spot-on for the prevention of flea infestations on cats.

The clinical application of a new method for using the insect growth regulator, pyriproxyfen, for controlling flea populations in cat-owning homes is evaluated for the first time. In a multicentric, controlled and randomised trial, 107 flea-infested cats were treated with a minimum dose of 10 mg/kg bodyweight pyriproxyfen as a 10 per cent spot-on application on two occasions, with a three-month interval between doses. For comparison, 99 cats received lufenuron suspension orally, once a month, for six months. Flea counts decreased significantly over time in each group and were significantly lower in the pyriproxyfen group than in cats treated with the reference product. The percentage of 'zero-flea' cats increased from 49 per cent on day 30 to 88 per cent on day 180 in the pyriproxyfen group and from 30 to 71 per cent in the lufenuron group at the same time points (P<0.05). Appropriately timed topical applications of pyriproxyfen, therefore, offer a method of flea control in the domestic environment.

Administration, Cutaneous↗
PubMed2000

Resting brain metabolic activity in a 4 tesla magnetic field.

MRI is a major tool for mapping brain function; thus it is important to assess potential effects on brain neuronal activity attributable to the requisite static magnetic field. This study used positron emission tomography (PET) and (18)F-deoxyglucose ((18)FDG) to measure brain glucose metabolism (a measure of brain function) in 12 subjects while their heads were in a 4 T MRI field during the (18)FDG uptake period. The results were compared with those obtained when the subjects were in the earth's field (PET scanner), and when they were in a simulated MRI environment in the PET instrument that imitated the restricted visual field of the MRI experiment. Whole-brain metabolism, as well as metabolism in occipital cortex and posterior cingulate gyrus, was lower in the real (4 T) and simulated (0 T) MRI environments compared with the PET. This suggests that the metabolic differences are due mainly to the visual field differences characteristic of the MRI and PET instruments. We conclude that a static magnetic field of 4 T does not in itself affect this fairly sensitive measure of brain activity.

Adult↗
PubMed1997

Management of children with potential anaphylactic reactions in the community: a training package and proposal for good practice.

BACKGROUND: The increase in potentially dangerous food allergic reactions (e.g. to peanuts and nuts) in children had lead to an increase in the prescription of adrenaline, including adrenaline for self- or parent-injection. This raises problems in the management of these children in schools. Our experience in response to this is described. OBJECTIVE: To develop a training package to ensure that each child can continue at school but receive optimum emergency treatment in a safe environment. To provide education, training and support to school staff, and to support parents. METHODS AND RESULTS: This paper describes a model of good practice in the support of children with potentially fatal anaphylactic reactions. The following points are emphasized. Children with a history of anaphylactic reactions should be expertly assessed prior to the prescription of adrenaline injection. A written treatment plan is essential. Parents need expert support in managing the child. Schools need training and support. Children should lead a normal life, and not be stigmatized or labelled by their problem. Close liaison between primary care, acute services, community services and education services are essential for the successful management of this problem. Data from a questionnaire showed the training package was of benefit, with considerable reduction in anxiety in school staff and parents. CONCLUSION: A broad training package is essential: training in administration of adrenaline is only one aspect, and emphasis is placed on education, recognition of allergic reactions and prevention. The presence of children in school needing access to adrenaline is no longer perceived as a problem in our area. We recommend other health authorities provide a similar service.

Anaphylaxis↗