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Biomedical subjects

A T Williams

Publications and source records attributed to A T Williams.

41 records · Page 3Linked to original sources
PubMed1978

Changes in retinal correspondence following surgery for intermittent exotropia.

An intermittent exotrope of 54delta had harmonious anomalous correspondence when squinting and normal correspondence when bifoveally fixating. Measures of the angle of deviation (H) and angle of anomaly (A) were made at the first postoperative dressing 6 hr after surgery (H = 8--14delta esotropia, A = 0--54delta exo) and at several times over a 2.5-mo period during which a second operation was performed. The final result was 3delta of exophoria with normal correspondence when fusing and harmonious anomalous correspondence (A = 3delta exo) when fusion was disrupted. The change in angle of anomaly created by the surgery cannot be explained by changes in fusional vergence. Halldén's "sensory-fusion" mechanism, which is based on diplopia resulting from stimulation of disparate retinal points, is more useful in explaining the obtained results.

Adult↗
PubMed1978

The O'Connor cinch revisited.

The modified O'Connor cinch operation is a useful, but little used, adjustable resection operation. For increased understanding of its shortening and adjustment characteristics, a standard cinch was performed in animals and patients with strabismus. Animal studies showed that, as each strand of the cinch was removed, a small, relatively equal release of the cinch effect occurred. Measurement of the shortening obtained in patients with strabismus showed a consistent resection effect of about 4 mm. Review of 17 cases in which the cinch was used as part of the surgical treatment showed the technique to be adjustable by reducing the overcorrection in 6 cases. Ten to 20 prism dioptres of reduction in the deviation was obtained with adjustment of the cinch on the first postoperative day. All 17 cases had satisfactory adjustment. The largest residual deviation was 12 prism dioptres.

Adolescent↗
PubMed1977

A fluorescence detector for high-pressure liquid chromatography.

We describe a fluorescence spectrophotometer adapted with a micro quartz flow cell to record the output of modern liquid chromatographs. The optical system is double beam in that the light source variations are cancelled out by a second photomultiplier, thus enhancing the sensitivity of the technique. The emission spectra may be scanned by stopping the flow in the chromatographic column and scanning the fluorescence detector. Many specific applications have been studied: polycyclic aromatic hydrocarbons, several vitamins, porphyrins, methyl anthranilate, etc. These are studied in natural samples and it is shown that the specificity of the fluorescence detector frequently obviates the need for sample preparation. The sensivitity available with the fluorescence detector for fluorescing compounds is often much greater than is available with variable-wavelength ultraviolet spectrophotometers. We report picogram-level detectability in real samples for many of the compounds that we have studied.

Animals↗