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Biomedical subjects

L A Wright

Publications and source records attributed to L A Wright.

7 recordsLinked to original sources
PubMed1992

Visual problems in the elderly population and implications for services.

OBJECTIVE: To determine the prevalence of visual disability and common eye disease among elderly people in inner London. DESIGN: Cross sectional random sample survey. SETTING: Inner London health centre. SUBJECTS: Random sample of people aged 65 and over taken from practice's computerised age-sex register. MAIN OUTCOME MEASURES: Presenting binocular Snellen 6 m distance acuity and best monocular 3 m Sonksen-Silver acuity to classify prevalence of blindness by World Health Organisation criteria (less than 3/60 in better eye) and American criteria for legal blindness (better eye equal to 6/60 or less) and of low vision by WHO criteria (best acuity 6/18) and visual impairment by American criteria (less than 6/12 or 20/40 but greater than 6/60 or 20/200 in better eye). Principal cause of visual loss by diagnosis, referral indication by cause to hospital eye service, and proportion of cases known to primary care. RESULTS: 207 of 288 (72%) eligible people were examined. 17 (8%) housebound subjects were examined at home. The prevalence of blindness was 1% by WHO criteria and 3.9% by American criteria. The prevalence of low vision (WHO criteria) was 7.7%. The prevalence of visual impairment (American criteria) was 10.6%. Cataract accounted for 75% of cases of low vision. Only eight out of 16 patients with low vision were known by their general practitioner to have an eye problem. 56 subjects (27%) would probably have benefited from refraction. Comparisons with studies in the United States and Finland suggested higher rates in this sample, mainly due to the prevalence of disabling cataract. CONCLUSION: There seems to be a considerable amount of undetected ocular disease in elderly people in the community.

Aged↗
PubMed1992

Stereopsis and ageing.

This study reports the prevalence of defective stereopsis in an elderly population. Of 728 individuals over the age of 65 who attempted a Frisby stereotest, only 27% had full stereopsis and 29% had no stereopsis. In the elderly population defective stereopsis is a common finding in the absence of any other ocular morbidity. The prevalence of defective stereopsis increased with age. This finding was noted as a part of a survey of eye health of elderly people living in an inner city. The finding was not associated with any symptoms. The significance of this finding is discussed.

Aged↗
PubMed1991

Ocular responses in healthy subjects to topical bunazosin 0.3%--an alpha 1-adrenoceptor antagonist.

The ocular effects of the alpha-adrenoceptor blocking drug bunazosin, administered as eyedrops, have been measured in a placebo-controlled double-blind single-dose study in 15 healthy volunteers. The drug significantly reduced intraocular pressure over 10 hours, and there was no associated change in pulsatile ocular blood flow. Characteristic effects of alpha-adrenoceptor blockade were observed--miosis, ptosis, and conjunctival hyperaemia. The miosis alone persisted for more than 24 hours in nine out of 15 subjects.

Adrenergic alpha-Antagonists↗
PubMed1990

Development of a preformulation lipophilicity screen utilizing a C-18-derivatized polystyrene-divinylbenzene high-performance liquid chromatographic (HPLC) column.

Alkane/water partition coefficients have been predicted from the retention times of solutes using a C-18-derivatized polystyrene-divinylbenzene HPLC column (Act-I). Several classes of compounds, with molecular weights from 78 to 379 and partition coefficients ranging over several orders of magnitude, were included in the present study. A high correlation coefficient (0.953) was obtained from log-log plots of alkane/water partition coefficients versus capacity factor. A poor correlation was observed for octanol/water partition coefficient, presumably due to the hydrogen-bonding capability of octanol. The alkane/water correlation suggests that the system is devoid of significant specific solute-stationary phase interactions which are known to impart anomalous retention behavior to traditional reverse phase columns. Deviations of calculated alkane/water partition coefficients (and Hansch II alkane coefficients) from observed values could not be explained in terms of solute (or substituent) polarizability, dipole moment, sigma para, or pKHB values, further suggesting that specific interactions between the stationary phase and the solute are not significant. A molecular weight dependence that was independent of lipophilicity was observed. Thermodynamic and extra-thermodynamic parameters of retention were obtained in order to investigate retention mechanisms for the Act-I column. The molecular weight dependence does not appear to be due to size exclusion or entropic expulsion of the solute from the stationary phase. Hansch II substituent coefficients calculated from retention times were found to be similar for benzene and steroid derivatives. Thus, the Act-I column may be utilized as a rapid lipophilicity screen for drug candidates of similar molecular weight.

Alkanes↗
PubMed1989

Otrivine-antistin-pupil, corneal and conjunctival responses to topical administration.

The ocular effects of Otrivine-Antistin eyedrops have been measured in a placebo controlled single-blind study in sixteen healthy volunteers. The drops produced mild sympathomimetic responses in the eye but had no effect on corneal sensitivity or on intraocular pressure. The evidence indicates that use of Otrivine-Antistin imposes no risk to the subject.

Administration, Topical↗
PubMed1975

Photoreactivation of nitrate reductase production in Nicotiana tabacum var. Xanthi.

Ultraviolet (254 nm) irradiation of liquid-cultured tobacco cells inhibited the production of nitrate reductase; subsequent illumination with white light allowed a partial restoration of the synthesis of the enzyme (photoreactivation). Ultraviolet irradiation of these same cells also inhibited their ability to incorporate labeled uridine and labeled amino acids. Subsequent illumination with white light gave a partial restoration of the ability of the cells to incorporate uridine while a similar post-ultraviolet-irradiation treatment failed to restore the amino acid incorporation. The system in tobacco known to repair ultraviolet-damaged viral RNA thus does not seem to repair ultraviolet damage to the protein-synthesizing system of the cell. The photoreactivation of nitrate reductase production is best explained by the action of a DNA photorepairing system.

Amino Acids↗