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Biomedical subjects

P N Young

Publications and source records attributed to P N Young.

At least 19 recordsLinked to original sources
PubMed1988

A comparison of glyceryl trinitrate and labetalol as hypotensive agents in microsurgery of the middle ear.

Ninety-five patients undergoing microsurgery of the middle ear were anaesthetised using thiopentone, nitrous oxide, oxygen and halothane via a low flow circle system, with carbon-dioxide absorption. Systolic blood pressure was reduced to approximately 65 mmHg either by the use of increments of labetalol, or by an infusion of glyceryl trinitrate (GTN). The degree of haemostasis achieved was assessed by the surgeon who was unaware which hypotensive agent was being used. Both hypotensive agents produced good conditions in all patients. Thus GTN is a suitable agent to induce hypotension for this type of microsurgery.

Adolescent↗
PubMed1986

Hypotensive anaesthesia for microsurgery of the middle ear. A comparison between isoflurane and halothane.

Fifty patients undergoing microsurgery of the ear were anaesthetised using thiopentone, nitrous oxide, oxygen and either halothane or isoflurane, via a low flow circle system with carbon dioxide absorption. Systolic blood pressure was reduced to approximately 70 mmHg by the additional use of increments of labetalol; the patients breathed spontaneously. The degree of haemostasis was assessed by the surgeon who was unaware which volatile agent was being used to supplement anaesthesia. Isoflurane, although it is a potent vasodilator produced operating conditions which were indistinguishable from halothane. Isoflurane is thus a safe and reliable alternative to halothane as a volatile agent used to supplement anaesthesia when using induced hypotension for middle ear surgery.

Adolescent↗
PubMed1982

Hypotensive anaesthesia for microsurgery of the middle ear. A comparison between enflurane and halothane.

One hundred patients undergoing microsurgery of the ear were anaesthetised using thiopentone, nitrous oxide, oxygen and either halothane or enflurane with spontaneous respiration. Blood pressure was reduced to approximately 70 mmHg by the use of hypotensive agents. The efficacy of halothane and enflurane in producing good operating conditions was compared during this technique. Haemostasis was assessed by the surgeon who was unaware which volatile agent was being used. Both agents were found to be satisfactory and enflurane was shown to be a safe and reliable agent with this technique should an alternative to halothane be required. No impairment of renal function was seen with either agent in combination with hypotension.

Adolescent↗
PubMed1976

Long-term effects of neonatal steroid exposure on mammary gland development and tumorigenesis in mice.

Newborn female mice of three strains--BALB/cfC3H [mammary tumor virus (MuMTV)-infected], BALB/c, and C57BL (both virus-free)--were given injections of 17beta-estradiol or testosterone, alone or in combination with ovine prolactin, for the first 5 days of life. Half of each group of mice were ovariectomized at 40 days of age, and all mice were killed between 6 and 16 months of age. Mammary glands of BALB/cfC3H mice receiving steroid hormones were better developed than those of mice not receiving steroids. Androgen induced a higher incidence of grossly dilated ducts and secretion-filled alveoli. Mammary nodule and tumor incidences were higher in steroid-treated mice than in controls; androgen resulted in higher incidences than did estrogen. The age of onset of mammary tumors was also earlier after neonatal steroid treatment. In BALB/c mice, neonatal injections of estrogen induced some alveolar development of the mammary gland; neonatal injections of ovine prolactin had a greater effect. The mammary glands of C57BL mice did not show any evidence of stimulation by neonatal hormone treatment, which indicated the probability of strain differences. However, no nodules or tumors occurred in these MuMTV-free strains. Therefore, MuMTV was essential for neoplastic mammary responses to neonatal hormone treatment. Ovariectomy prevented alveolar development and abnormal changes in the mammary glands of all groups, thus indicating that ovary-independent alterations in the mammary gland were not induced by neonatal steroid treatment. We concluded that neonatal steroid exposure resulted in increased mammary tumor risk in mice, but only in the presence of both MuMTV and ovaries.

Animals↗
PubMed1976

Day stay anaesthesia. A follow-up of day patients undergoing dental operations under general anaesthesia with tracheal intubation.

Ninety-five patients who had undergone extensive dental surgery as day-patients were followed-up by questionnaire. An unexpectedly high incidence of after-effects was found; 78% of the patients went home with at least one persistent symptom due to the anaesthetic. A particularly high incidence of headache was found. There appeared to be no correlation of the symptoms with age, sex or nature or duration of the operation.

Adolescent↗
PubMed1975

Adrenocortical function: corticosterone levels in female BALB/c and C3H mice under various conditions.

A diurnal rhythmicity in plasma corticosterone levels was demonstrated in female BALB/cCrgl and C3H/Crgl mice, with and without mammary tumor virus. Removal of the adrenals followed by metopirone treatment reduced circulating corticoid to non-detectable levels in C3H but not in BALB/c mice. Dexamethasone strains. Neonatal exposure to exogenous hormones failed to cause any obvious change in corticoid levels. Bilateral ovariectomy of these neonatally treated mice at 40 days of age resulted in a subsequent lowering of plasma corticoid levels when compared with intact animals.

Adrenal Cortex↗