Biomedical subjects
Publications and source records attributed to S M Tucker.
We report a neonate, born at term, with microcephaly, a hypoplastic nose, exophthalmos, gum hyperplasia, cleft palate, and low set ears, who died at 86 minutes of age. Radiographs showed diffuse sclerosis of the bones.
We report a patient with a rare form of laceration through the lower punctum, vertical canaliculus, ampulla, and lower eyelid. A modification of a standard canalicular laceration repair involving the use of silk stent in the canalicular system is described.
We describe using a scaffold of free periosteum as a posterior lamella replacement in the reconstruction of large defects involving the lower lid. Although the tarsoconjunctival flap is the treatment of choice in lower lid defects, the technique we describe is especially useful in cases in which it is best not to cover the eye for an extended period, and in cases involving defects extending beyond those of the lower lid.
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We propose a simple technique for modifying a Jones bypass tube to prevent extrusion. It has been used in eight patients followed for 3 months to 3 years, without evidence of extrusion.
Four infants who were exposed to sodium valproate or valproic acid during pregnancy are described. Common facial features in the three surviving infants include epicanthic folds, a flat nasal bridge, a broad nasal base, anteverted nostrils, a shallow philtrum, and a thin upper lip with a thick lower lip. Ridging of the metopic suture, congenital heart defect, postaxial polydactyly, and hypospadias were additional features in individual cases. In agreement with previous authors, we feel that there is a distinctive 'fetal valproate' phenotype.
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When given intravenously to unanesthetized rats as a bolus dose, (-)-nicotine produced a dose-related rise in blood pressure and fall in heart rate in the dose range of 5-40 micrograms/kg. Tolerance did not develop when doses were given at 30 min intervals. At the highest dose, the effects on heart rate persisted. In addition, severe arrhythmias and apnea were observed. (+)-Nicotine at 100 micrograms/kg produced effects similar to 10 micrograms/kg of (-)-nicotine. When given at 1 min intervals, tolerance quickly developed after only 6 injections at 5 micrograms/kg and after 4 injections at 10 micrograms/kg. Tolerance to (+)-nicotine also developed rapidly and was no longer evident at 5 min. The results suggest the tolerance is related to frequency of administration and dose. The implication of these results are discussed with regard to cardiovascular disease and dependence. In addition, we postulate that the relatively low degree of biological stereoselectivity of the optical isomers of nicotine, compared with that of the enantiomers of morphine, is due to the simplicity and flexibility of the nicotine molecule. It can be shown using Dreiding models that the nitrogen atoms in the enantiomers are nearly superimposable.
The auditory response cradle is being used in a mass hearing screening project. Babies are assessed in the first week after birth by the fully automatic, microprocessor controlled cradle. The test, lasting from two to 10 minutes, compares physiological auditory responses to natural behaviour measured in control trials. More than 5000 babies have been tested and full follow up information at the age of 7 to 9 months is available from over two thirds of these. Less detailed information is available for 71% and 64% of those babies who have been followed up at 18 months and three years of age respectively. A total of 439 of 5553 neonates tested failed the first screening test. Eighty eight (1 X 6%) failed a second screening test while still in the maternity unit but 61 of these were subsequently shown to be normal, giving a false positive rate of 1 X 1%. The babies who failed the screening tests included 9 with sensorineural hearing loss, three with secretory otitis media, and three with abnormal auditory brain stem response tests. One child who passed the initial screening tests was found to have a moderately severe hearing loss at the age of 18 months.
The role of the neurotransmitters, norepinephrine, dopamine and serotonin in stress-induced antinociception (SIA) was examined by altering neurochemical tone with appropriate pharmacological tools. Quipazine (15.0 mg/kg, IP) a serotonin agonist, increased the peak and duration of antinociception following stress and BC-105 (3.0 mg/kg, IP), a serotonin antagonist, blocked the increase of tail-flick latency following stress. Clonidine (0.1 mg/kg, SC) an alpha 2 agonist, markedly decreased SIA whereas phenoxybenzamine (2.5 mg/kg, IP), an alpha 1 antagonist, increased the peak and duration of SIA. When dopaminergic tone was increased with apomorphine (0.05 mg/kg, SC) the increase of tail-flick latency after stress was markedly attenuated whereas blockage of dopamine receptors with haloperidol (2.5 mg/kg, IP) increased the peak and duration of SIA. Alterations of serotonergic, but not noradrenergic or dopaminergic, tone had similar effects on increased latency in tail-flick test produced by brain stimulation produced analgesia (SPA), morphine and SIA. These data support the hypothesis that alterations in tail-flick latency involves a serotonergic system.
The Bourns LS-75 Ventilation Monitor is compared with industrial flow standards in a closed test loop. Accuracy was found to be better than 2.5% of full scale. Changes in gas composition, temperature, pressure or humidity caused the flow meter to change by less than +/- 4% of reading.
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A family from Iraq with five growth hormone deficient children in two closely related sibships is reported. The clinical forms and modes of inheritance of familial growth hormone deficiency are discussed briefly.
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Vitamin D intakes of infants aged 6 and 18 months from the Asian community in Southhall, Middlesex, were studied to assess the effectiveness of food fortification as a means of preventing vitamin D deficiency. Infants aged 6 months generally had similar diets to white children of the same age and had reasonable vitamin D intakes owing to consumption of fortified dried milks and cereals, reinforced by health visitors and baby clinics. Children aged 18 months, however, ate largely Asian diets and had much lower vitamin D intakes than the 6-month-old group with a corresponding increase in symptoms of vitamin D deficiency. Hence new measures for preventing vitamin D deficiency should probably be aimed at children aged over 1 year. The results of this survey suggest that fortifying chapati flour would be the most effective method of doing this.
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