Section of Ophthalmology: Meeting Held at Manchester Royal Eye Hospital: Isolated Oculomotor Palsy Caused by Intracranial Aneurysm

The present paper is concerned with the 55 aneurysms out of a total of 158 that caused isolated paralysis of the oculomotor nerve. The majority arose from the internal carotid artery after it had pierced the dura (supraclinoid). Rarely the aneurysm sprang from the basilar artery. In two-thirds of the cases there had been a subarachnoid hæmorrhage from leakage. Not more than 10% of patients had arteriosclerosis. Calcification of the sac is not a sign that the aneurysm has thrombosed. The only certain way of demonstrating the position and size of an intracranial aneurysm is by arteriography, which is a safe procedure.The correct treatment is by carotid ligature. In about 8% of normals the circle of Willis is incomplete, therefore percutaneous compression must first be tried. The only fatalities from ligature were in persons in the acute stage of subarachnoid hæmorrhage, not from meningeal bleeding alone. In this type of case a clip applied to the neck of the sac is probably a better method. In the more usual cases where the hæmorrhage has been spontaneously arrested common carotid ligature in the neck is probably a little safer than intracranial clipping.     

STUDIES ON MENINGOCOCCUS INFECTION : III. THE ANTIGENIC COMPLEX OF THE MENINGOCOCCUS—A TYPE-SPECIFIC SUBSTANCE

Three fractions have been isolated from autolysates of the meningococcus. Of these, one, the type-specific substance, has been described in detail. The same type-specific substance appears to be present in Type I and Type III organisms, but a substance differing at least serologically has been obtained from Type II strains. Detailed chemical analysis of both of the type-specific substances thus far isolated is being carried out and will be the subject of a later paper.     

CORNEAL THICKNESS AND DIAMETER IN THE DOMESTIC CAT

Two sample groups of domestic cats were assessed for (a) central corneal thickness (17 eyes), using optical pachymetry, and (b) horizontal and vertical corneal diameter, using a photographic method (20 eyes). The average corneal thickness was 0.755 +/- 0.33 mm. The mean horizontal diameter was 16.5 +/- 0.60 mm and the mean vertical diameter was 16.2 +/- 0.61 mm. The horizontal corneal diameter was significantly greater than the vertical corneal diameter (p less than 0.001, paired t test).     

Screening for colorectal cancer: A critical review

This article discusses the place of symptom detection, endoscopy, and fecal occult blood testing in population screening for colorectal cancer. There is now considerable evidence that screening the population over the age of 50 years for occult blood in the feces will result in an increased yield of tumors localized to the bowel at the time of surgical treatment. These tumors also have other favorable prognostic features and it is likely that the prognosis of this group will be better than the prognosis of patients presenting with symptoms in the usual way. Because of the biases that result from the selection and detection of tumors in screening studies, the mortality results of the control trials now underway must be awaited until it is known whether population screening is of real value. In chemical fecal occult blood screening tests, a compromise has to be made between sensitivity and specificity. The fecal occult blood test most widely used and the one that has been subjected to the most evaluation in screening studies is the guaiac-based slide test, Hemoccult. The predictive value of a positive test for invasive cancer is 11–17%, and for adenomas, 36–41%. This specificity is achieved at a loss of sensitivity, the interval cancer rate reported in screening studies being over 20%. Newly developed immunological techniques appear to be more sensitive and specific, but require further evaluation in population screening studies.

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Resumen Este artículo revisa el valor de las pruebas de tamizaje para cáncer colorrectal a saber: detección de síntomas intestinales, endoscopia, y examen de sangre oculta en heces. Hoy existe evidencia considerable de que el tamizaje de la población de edad mayor de 50 años mediante el examen de sangre oculta en heces résulta en un aumento en el número de tumores localizados (sin extensión regional) encontrados en el momento de realizar el tratamiento quirúrgico. Los tumores en este estadio exhiben otras características favorables en cuanto a pronóstico, y es posible que el pronóstico en este grupo sea mejor que en los pacientes que se presentan con la sintomatología usual. Sin embargo, debido al sesgo que resulta de la selección y detección de tumores en los estudios de tamizaje, los resultados de mortalidad que emergen de los ensayos controlados actualmente en progreso deben esperar hasta cuando se conozca si el tamizaje poblacional es de real valor.En la realización de las pruebas de tamizaje de sangre oculta en heces, hay que asumir una transacción entre sensibilidad y especificidad. La prueba de sangre oculta mayormente utilizada y la que ha sido sometida a mayor evaluación en los estudios de tamizaje es la de laminilla con guayaco, Haemocult. El valor predictivo de una prueba positiva para cáncer invasivo es 11–17%, y para adenomas, 36–41%. Este nivel de especificidad se logra a costa de una pérdida de sensibilidad; la tasa de cáncer de intervalo reportada en los estudios de tamizaje superior a 20%. Las técnicas inmunológicas recientemente desarrolladas parecen ser más sensibles y específicas, pero requieren mayor evaluación en los programas de tamizaje poblacional.

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Résumé Dans cet article, on traite la place de la détection des symptômes, de l'endoscopie, et de la recherche de sang occulte dans les selles pour le dépistage du cancer colorectal. Il est maintenant prouvé que la recherche de sang occulte dans les selles augmente le pourcentage de tumeurs colorectales découvertes sans extension extradigestive au moment de la chirurgie. Ces tumeurs ont d'autres caractéristiques pronostiques favorables et il est possible que le pronostic des tumeurs détectées de cette manière soit meilleur que pour les patients présentant des symptômes classiques de tumeurs colorectales.Cependant en raison des biais dus aux modes de sélection et de détection des tumeurs décelées par cette méthode de dépistage, il faut attendre les résultats sur la mortalité des essais contrôlés actuellement en cours pour savoir si ce dépistage est valable. Il existe un compromis entre la sensibilité et la spécificité des tests destinés à détecter le sang occulte dans les selles. Le test le plus utilisé et le plus étudié de nos jours est l'Hémoccult, test basé sur la lecture d'une lame contenant le guaïc. La valeur prédictive positive du cancer invasif est de 11 à 17%, et celle de l'adénome est de 36 à 41%. Cette spécificité est atteinte aux dépens d'une perte de sensibilité, les cancers détectés dans l'intervalle (après un premier test négatif) de deux ans étant de 20%. Des techniques immunologiques nouvelles paraissent être plus sensibles et plus spécifiques mais nécessitent plus d'évaluation pour savoir si elles sont applicables aux études de dépistage de masse.

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Mr. G. Pye is supported by Medical Research Council Grant.     

Aging: effect on hepatic metabolism and transport of folate in the rat

Effects of aging on hepatic folate metabolism and transport were assessed in male Fisher 344 rats. Total serum and hepatic folate levels were measured. Hepatic folates were measured by high-performance liquid chromatography and by Lactobacillus casei assay. Transport of 5-methyltetrahydrofolate (5-CH3-H4PteGlu) was measured in isolated hepatocytes. Serum folate declined with aging; however, neither the total folate level nor the distribution of hepatic folate coenzymes was affected by the aging process. The level of liver folate monoglutamates was not significantly different in any group. The initial rate of uptake of 5-CH3-H4PteGlu was significantly decreased in hepatocytes from the 24-mo-old rats, as was the ability to concentrate this folate from the medium. Aged rats maintain apparently normal levels of hepatic folates despite decreased serum levels and decreased ability to take up folates, suggesting that membrane transport of folates may not be a limiting factor in hepatic folate assimilation.