Opacity of bovine cornea in vitro induced by surfactants and industrial chemicals compared with ocular irritancy in vivo.

The ability of 8 surfactants and 5 industrial chemicals to induce bovine corneal opacity in vitro was investigated using a simple specially constructed instrument, the opacitometer. Concentration-effect curves were constructed for each agent. The relative extent to which the agents caused the development of corneal opacity in vitro correlated well with published data on their ocular irritancy in vivo.

Prostatic cancer: some epidemiological features.

Prostatic cancer is a frequent tumour in old men. The disease is very common in North America, particularly among Blacks, and in Scandinavia, while it is currently rare in Asian countries. Both morbidity and mortality rates have increased in most areas in recent years, the rate of increase being greatest in populations where the risk has hitherto been low.

Birth cohort analysis using irregular cross-sectional data: a technical note.

Cancer mortality and morbidity data are usually collected and published by calendar time period and by age class. Transformation of the age-specific incidence or mortality rates into those for birth cohorts is readily undertaken when one age class of each time period corresponds to a given cohort: a requirement that is often not satisfied. The authors propose a method for the computation of birth cohort age-specific incidence rates given irregular cross-sectional data.

Diet and cancer: value of different types of epidemiological studies.

Diet and nutrition are increasingly recognized as likely to be major determinants of cancer, notably cancers of the gastrointestinal tract, breast, endometrium, ovary, and prostate. Dietary factors may collectively account for a greater proportion of all cancers that occur in contemporary Western society than does any other category of environmental exposure (1). With the development of knowledge of the protective properties of certain components of food, links with diet have been suggested for other cancer sites (2).

A simple method to assess surfactant-induced bovine corneal opacity in vitro: preliminary findings.

The in vitro development of bovine corneal opacity induced by two anionic surfactants, sodium decyl sulphate (NaDS) and sodium lauryl sulphate (NaLS), was monitored using a simple, specially constructed instrument, the opacitometer. Results show clearly that NaDS was more potent, and acted more rapidly, than NaLS, an order of potency which has been shown by in vivo ocular irritancy tests with these agents but not in cytotoxicity tests. The measurement of irritant-induced opacity of bovine isolated cornea may therefore offer another approach to the search for viable in vitro alternatives to in vivo ocular irritancy testing.

The cancer registry in cancer control--a review.

The author reviews key elements in the contribution of the cancer registry to cancer control. A cancer registry always requires the direct or indirect cooperation of the medical profession in the reporting of new cancer cases and it must in return provide services which the physician can use in the care of cancer patients. Survival of patients can be assessed and treatment evaluated for the entire reporting area and not just for selected groups.

The toxic effect of some industrial chemicals on rabbit ileum in vitro compared with eye irritancy in vivo.

The concentrations of acetone, acetophenone, allyl alcohol, n-butanol, carbitol, dioxane, ethanol, formaldehyde, iso-propanol, mercaptoethanol, methanol and propylene glycol required to block spontaneous contractions of rabbit isolated ileum by 50% (EC50) in vitro were determined. The EC50's correlated reasonably well with published data on rabbit eye irritation in vivo caused by these agents. Better correlation might be impossible to obtain owing to the subjective nature, and therefore relative unreliability, of in vivo eye testing.

The comparative toxic effects of proprietary antidandruff, adult and baby shampoos on rabbit ileum.

Each of four antidandruff shampoos, containing zinc pyrithione, was statistically significantly more potent at blocking spontaneous contractions of rabbit isolated ileum than was any of four adult shampoos which in turn were each significantly more potent that any of four baby shampoos tested. The ileum model therefore appears to be sufficiently sensitive to distinguish between antidandruff, adult and baby shampoos. It is suggested that if those who carry out in vivo eye irritancy testing also test their products on the ileum model then, over a period of time, this in vitro test might be proved to be a viable alternative to many of the in vivo tests currently carried out.

A novel approach to the search for in vitro alternatives to in vivo eye irritancy testing.

Cytotoxicity in terms of haemolytic potency in vitro of eight surfactants failed to correlate with in vivo rabbit eye irritancy. Ability of the same surfactants to block spontaneous contractions of mouse and rabbit isolated ileum (especially the latter), correlated better with in vivo findings in rabbit eyes. Effectiveness in blocking ileum contractions may depend both on ability to penetrate this tissue and to act at the target site.