PubMed Health⌕ Search

Biomedical subjects

C KAPLAN

Publications and source records attributed to C KAPLAN.

At least 19 recordsLinked to original sources
PubMed1960

Titration of vaccinia virus by intravenous injection of chick embryos.

The final test of a smallpox vaccine is its capacity to prevent the disease from developing in inoculated individuals. This capacity, however, cannot be measured directly, so that other methods of assessing the efficacy of vaccine have had to be developed. A laboratory method-pock counting on the chorio-allantoic membrane of chick embryos-has recently been shown to provide a reasonably reliable estimate of the number of infective units in a given vaccine. In this paper, the author compares this pock-counting method with another method-titration by intravenous injection of chick embryos. He concludes that, although the reproducibility of titrations by intravenous injection compares very favourably with that obtained by chorio-allantoic inoculation, the former method would not be advantageous for the assay of vaccines, since it is very time-consuming and since differences in virulence might obscure comparisons between the efficacy of vaccines.

Animals↗
PubMed1958

Studies with dried and glycerinated smallpox vaccines of full and diminished potencies.

In a further vaccination and laboratory study with two dried smallpox vaccines (designated "P" and "Q") and one glycerinated vaccine, the potency of samples of each vaccine was deliberately lowered by exposure to heat. Groups of volunteers were vaccinated with the fully potent vaccines and with those of reduced potency. All subjects who developed a vesicular response were challenged one year later by revaccination with a potent vaccine, and the results obtained in the different groups were compared. No significant variation could be detected in the response of the different groups to the challenge vaccination. These findings indicate that if vesiculation is obtained with a vaccine, even though potency has been reduced to a point where it produces less than 50% successful primary vaccinations, satisfactory protection will result one year later. It also appears that successful vaccination with a dried vaccine confers as good immunity as that obtained from glycerinated lymph. Vaccines with a pock count of 10(6) infective units per millilitre will produce about 40% successes in primary vaccination.

Hot Temperature↗
PubMed1957

Laboratory and vaccination studies with dried smallpox vaccines.

In a vaccination and laboratory study, two dried smallpox vaccines (designated P and Q) were tested at intervals of 4, 8, 16, and 32 weeks after storage at both 37 degrees C and 45 degrees C. Vaccine P was also tested after 64 weeks at these temperatures and gave 100% successful vaccination rates after all periods of storage at both temperatures. Vaccine Q deteriorated within four weeks, rapidly at 45 degrees C and less rapidly, but very substantially, at 37 degrees C. There was no clear evidence of the cause of this deterioration, but there was a suggestion of denaturation of some of the samples stored at the higher temperature. So far as could be ascertained, the laboratory results-rabbit skin scarification tests and chorio-allantoic membrane pock counts-ran parallel with the vaccination success rates. The pock count was found to be the more accurate method of laboratory titration. Vaccine P as used in the trial was not an exceptional batch.Vaccines which give a pock count of 10(8) infective units per ml will give the highest possible rate of successful primary vaccinations.A statistical note on the trials is given in an annex.

Animals↗