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Biomedical subjects

B Taylor

Publications and source records attributed to B Taylor.

At least 271 records · Page 15Linked to original sources
PubMed1982

Somatic motor axons can innervate autonomic neurones in the frog heart.

1. The effects of sympathetic and parasympathetic stimulation on the heart rate in frogs were tested after hearts were reinnervated with a somatic motor nerve. When frogs were vagotomized and hypoglossal axons were redirected to the heart for 8 or more weeks, stimulating the redirected hypoglossus nerve produced a parasympathetic-like inhibition of the heart. Stimulating sympathetic rami of the anastomosed hypoglossus nerve produced cardiac acceleration.2. Individual parasympathetic neurones received synaptic input from hypoglossal terminals. The excitatory post-synaptic potentials evoked by hypoglossal stimulation were much smaller than those evoked by vagal stimulation in control or vagal-reinnervated ganglia. However, hypoglossal axons innervated most (71%) of the ganglion cells and this level of innervation persisted for at least 60 weeks.3. Hypoglossal axons formed networks of varicose terminals within cardiac ganglia and established axo-axonic synapses with parasympathetic neurones. Hypoglossal terminals did not reinnervate the neuronal perikarya, in contrast to vagal axons in control or vagal-reinnervated ganglia.4. Axo-axonic synapses from redirected hypoglossal axons were identified in cardiac ganglia by bathing isolated hearts in horseradish peroxidase (HRP) and stimulating the redirected nerve. Electron micrographs showed that axo-axonic synapses contained HRP-labelled presynaptic vesicles.5. The source of foreign innervation in experimental cardiac ganglia was confirmed to be hypoglossal motoneurones (a), by comparing the conduction velocity of the redirected presynaptic axons (1.32 m/sec) with regenerating vagal preganglionic fibres (< 0.3 m/sec), and (b), by retrograde HRP-labelling of large motoneurones in the hypoglossal nucleus after applying peroxidase to the axons which had grown into the heart.

Animals↗
PubMed1982

Natural history of egg hypersensitivity.

Twenty-five children with clinical egg hypersensitivity, confirmed by double-blind challenge, were followed for between 2 and 2 1/2 years. Clinical egg hypersensitivity was fund to have resolved in 11 children but was persistent in 14. Skin prick tests reactions to egg were initially of equivalent size in the resolved and persistent groups, but became negative or diminished in size with resolution of clinical egg hypersensitivity, while remaining positive in the group with persisting symptoms. Symptoms after egg ingestion were categorised as cutaneous, gastrointestinal, respiratory, and angioedema. The adverse reactions of the resolved group were either cutaneous or gastrointestinal symptoms. The persisting group had multisystem involvement and most of them developed angioedema and respiratory symptoms. These differences may be useful as prognostic indicators in clinical egg hypersensitivity.

Child↗
PubMed1982

Dissociation of changes in the permeability of the blood-brain barrier from catecholamine-induced changes in blood pressure of normotensive and spontaneously hypertensive rats.

We have studied the effects of the pressor catecholamine, dopamine, and the depressor catecholamine, isoproterenol, on the systemic blood pressure and the permeability of the blood-brain barrier (BBB) to albumin in normotensive (WKY) and spontaneously hypertensive (SHR) rats. The rats were anesthetized with pentobarbital. The permeability of the BBB to protein was measured by the extravasation of radioiodinated serum albumin (RISA). The permeability was decreased by both catecholamines despite the dose-dependent, yet opposite, changes in blood pressure in the WKY rats. The blood pressure response to both of the catecholamines was enhanced in the SHR rats. Isoproterenol caused a decrease in the permeability of the BBB in the SHR but dopamine did not. Results with both WKY and SHR rats are suggestive of an adrenergically-mediated decrease in movement across the BBB of compounds of large molecular weight, regardless of changes in blood pressure.

Animals↗
PubMed1981

Salbutamol: tablets, inhalational powder, or nebuliser?

A study was carried out to ascertain the most effective method of giving salbutamol. Seventeen children with severe asthma received active salbutamol (4 mg via a nebuliser, 400 micrograms as an inhalational powder, or a 4 mg tablet) together with complementary placebos on a double-blind, triple-dummy randomly allocated basis. The bronchodilatation effect was assessed by measuring the peak expiratory flow rate. The bronchodilatation effect was greatest when patients received nebulised salbutamol (p less than 0.05) but lasted longest when they received the tablet (p less than 0.0001); the onset of the effect was rapid with all forms of administration. These results indicate that nebulised salbutamol gives the best relief in severe asthma; in less severe cases, however, a regimen combining the inhalational powder and tablets is sufficient and more convenient.

Aerosols↗
PubMed1981

Sodium cromoglycate: spincaps or metered dose aerosol.

1 Sodium cromoglycate administered as a dry powder inhalation (20 mg/dose) via the Spinhaler was compared with a metered dose aerosol (2 mg/dose) in an eight week double dummy double blind crossover trial in 29 asthmatic children. 2 The powder formulation was associated with significantly less symptoms (night wheeze, night cough, day wheeze, day cough, activity) and bronchodilator intake; and significantly greater weight gain than aerosol therapy. There were no significant differences in morning or evening peak flow measurements on the two treatments. 3 The powder may be more effectively inhaled than the aerosol or the dose of the aerosol may not be large enough.

Adolescent↗
PubMed1981

Eczema and infant diet.

The relationship between prenatal atopy, breast-feeding, early solid food diet and the rate of eczema was studied in a birth cohort of 2-year-old children. Rates of eczema varied significantly with parental atopy and solid feeding: children of atopic parents given solid food during the first 4 months had over two-and-a-half times the rate of eczema of children not given solid food and who had non-atopic parents. Further, rates of eczema increased in almost direct proportion to the number of different types of solid food that the child had been given during the first 4 months. Breast-feeding had no significant effect on rates of eczema. The results suggest that both parental atopy and diversity in early diet are factors which contribute towards rates of childhood eczema.

Analysis of Variance↗
PubMed1981

House dust mite counts in different types of mattresses, sheepskins and carpets, and a comparison of brushing and vacuuming collection methods.

Mite counts were compared in dust from three types of mattresses. Foam rubber mattresses appear preferable for mite sensitive atopic subjects; the surface of kapok mattresses averaged twice, and innerspring mattresses three times, the number of mites per square metre found on foam rubber mattresses (P less than 0.01). Sheepskins used for infant bedding were also found to be heavily infested, harbouring as many mites per square metre as bedroom carpet. Mite collections are best made with vacuum sampling methods in preference to a brush and results are best expressed in mites/m2.

Animals↗
PubMed1981

Parental smoking and lower respiratory illness in the first three years of life.

The relationships between parental smoking and the rates of lower respiratory illness during the first three years of life were examined for a birth cohort of 1265 New Zealand children. Lower respiratory illness varied significantly with maternal smoking for the first year; there was equivocal evidence of a relationship between maternal smoking and lower respiratory illness in the second year; and by third year the relationship had clearly disappeared. Paternal smoking had no significant effect on rates of lower respiratory illness at any time. Application of logistic regression showed that for the first year rates of lower respiratory illness were approximately linearly related to maternal smoking: increases of five cigarettes a day resulted in an increase of 2.5 to 3.5 incidents of lower respiratory illness per 100 children at risk. Statistical control for maternal age, education, family size, and family living standards showed that the relationship between maternal smoking and rates of lower respiratory illness was not significantly influenced by these factors.

Bronchitis↗
PubMed1981

Atopy in medical students.

Personal and immediate family histories of symptomatic atopy (asthma, eczema or allergic rhinitis) and reactivities on allergen skin prick testing were assessed in 165 medical students. Over-all, 43.0% showed a positive skin prick test to one or more allergens, 32.7% had symptomatic atopy and 55.8% had positive immediate family histories. Although the over-all incidence of skin prick test atopy is comparable with previously reported studies, the prevalence of personal and family symptomatic atopy is high in this population, especially in the female students who were significantly more likely than the males to have atopic symptoms and immediate family histories of atopic symptoms.

Asthma↗