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Biomedical subjects

S M Tucker

Publications and source records attributed to S M Tucker.

At least 19 recordsLinked to original sources
PubMed1992

Corneal diameter, axial length, and intraocular pressure in premature infants.

PURPOSE: Seventy premature infants 25 to 37 weeks' postconceptional age were examined during their first week of life to determine the correlation of corneal diameter, axial length, and intraocular pressure with gestational age and birth weight. METHODS: Corneal diameter measurement was determined with corneal templates, total axial length with standardized A-scan ultrasound, and intraocular pressure with a Tonopen II tonometer. RESULTS: Corneal diameter and total axial length showed parallel linear increases from 6.2 mm to 9.0 mm and 12.6 mm to 16.2 mm, respectively; however, no significant correlation was found between intraocular pressure and gestational age or birth weight. The mean intraocular pressure was 10.3 mmHg (standard deviation, 3.5). CONCLUSION: Normative values are established for corneal diameter and total axial length as they relate to birth weight and gestational age, and a mean and standard deviation for intraocular pressure in the premature newborn. These values will aid the ophthalmologist in assessing ocular dimensions in premature infants.

Birth Weight↗
PubMed1992

Screening of hearing impairment in the newborn using the auditory response cradle.

The Auditory Response Cradle (ARC) is a fully automated microprocessor controlled machine that was designed for the hearing screening of full term neonates. In order to evaluate the ARC, 6000 babies were screened at a district maternity hospital over a period of three years. Every infant subsequently entered a three year follow up programme. One hundred and two babies (1.7%) failed the ARC screen (that is, they failed two ARC tests) and 20 of these were found to have some hearing impairment: in 10 it was severe (80-90 dBHL), in seven moderate (45-60 dBHL), and in three it was mild to moderate (less than 45 dBHL). In addition, of the 20 babies who failed a first test and were discharged before a second could be performed, two were confirmed to have a severe hearing loss; 79 infants failing the screen were cleared on further testing, giving the ARC a false positive rate of 1.3%. On following up all 6000 infants for three years, seven children who passed the neonatal screen were subsequently found to have a hearing loss. For two babies the aetiology was unknown but for five the hearing impairment was either due to a hereditary progressive loss or definite postnatal factors. Progressive and acquired hearing losses cannot be detected at a neonatal screen and this emphasises the need for follow up screens at other stages in the child's life. In this long term study the ARC has been found to have a high detection rate for severe hearing loss and confirms the practical possibility of using a behavioural technique for the universal screening of hearing in neonates.

England↗
PubMed1989

Punctal and vertical canaliculus lacerations.

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.

Adolescent↗
PubMed1989

The use of free periosteal grafts in extensive lower lid reconstruction.

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.

Aged↗
PubMed1987

Fetal valproate syndrome: is there a recognisable phenotype?

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.

Abnormalities, Drug-Induced↗
PubMed1986

Rapid and brief tolerance to (+)- and (-)-nicotine in unanesthetized rats.

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.

Animals↗
PubMed1978

Vitamin D status of Asian infants.

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.

Age Factors↗
PubMed1978

Urinary excretion of lysozyme and N-acetyl-beta-D-glucosaminidase in the diagnosis of renal allograft rejection.

The urinary excretion of N-acetyl-beta-D-glucosaminidase (NAG) has been claimed to be of high diagnostic value in indicating acute renal graft rejection. Similar claims have been made for the significance of urinary lysozyme excretion. Serial measurements of urinary lysozyme and NAG have been made in 35 patients after renal transplantation, and during 52 suspected rejection episodes. A close correlation has been found between these two parameters although they did not consistently change in parallel. The use of both assays may give a better indication of impending rejection than either assay alone.

Acetylglucosaminidase↗