Post-thaw development of in vitro produced buffalo embryos cryopreserved by cytoskeletal stabilization and vitrification.

The present study was conducted to examine post-thaw in vitro developmental competence of buffalo embryos cryopreserved by cytoskeletal stabilization and vitrification. In vitro produced embryos were incubated with a medium containing cytochalasin-b (cyto-b) in a CO(2) incubator for 40 min for microfilament stabilization and were cryopreserved by a two-step vitrification method at 24 degrees C in the presence of cyto-b. Initially, the embryos were exposed to 10% ethylene glycol (EG) and 10% dimethylsulfoxide (DMSO) in a base medium for 4 min. After the initial exposure, the embryos were transferred to a 7 microl drop of 25% EG and 25% DMSO in base medium and 0.3 M sucrose for 45 sec. After warming, the embryos were cultured in vitro for 72 h. The post-thaw in vitro developmental competence of the cyto-b-treated embryos did not differ significantly from those vitrified without cyto-b treatment. The hatching rates of morulae vitrified without cyto-b treatment was significantly lower than the non-vitrified control. However, the hatching rate of cyto-b-treated vitrified morulae did not differ significantly from the non-vitrified control. This study demonstrates that freezing of buffalo embryos by cytoskeletal stabilization and vitrification is a reliable method for long-term preservation.

An investigation on the use of data-driven scattering profiles in Monte Carlo simulations of ultraviolet light propagation in skin tissues.

Ultraviolet light can affect the appearance and medical condition of the human skin by triggering biophysical processes such as erythema, melanogenesis, photoaging and carcinogenesis. The evolution of these processes is related to the amount of ultraviolet light absorbed by skin pigments. This amount may vary with the wavelength and path length of the radiation that is propagated within the skin tissues. For many years, biomedical researchers have been investigating the propagation of ultraviolet light in skin tissues through Monte Carlo simulations. The scattering of the incident radiation by tissue internal structures, a key component in this process, is usually approximated by functions without a plausible connection with the underlying physical phenomena. In this paper, we examine the origins of such an approach, and question its generalized use with respect to wavelengths and biological materials for which there is no supporting data available. Furthermore, we perform comparisons to demonstrate that the accuracy and predictability of Monte Carlo simulations of ultraviolet propagation in skin tissues can be improved by using a data-driven approach to represent the scattering profile of these tissues.

Studies on the efficacy of some post-service intrauterine infusions on the conception rate of repeat breeding cattle.

The efficacy of post-insemination intrauterine infusion of Strep to-penicillin, Lugol's solution, one and two vials of Mastalone-U (Pfizer, Bombay, India, containing a combination of oxytetracycline hydrochloride, oleandomycin phosphate, neomycin sulphate, prednisolone and chlorpheniramine maleate) and distilled water was compared on the basis of conception rate with that of control in repeat breeder cows. The results indicated that there was no significant difference between the treated groups and the control, except that with two vials of Mastalone-U, the conception rate was significantly low (P<0.05). The results of the present trial suggest that intrauterine infusions for the treatment of repeat breeding cows should not be used indiscriminately.

Quantitative organ culture: an approach to prediction of tumour response.

Quantitative organ culture provides a simple in vitro method for assessing tumour responsiveness. The value of using 125IUdR incorporation as a reproducible index of DNA synthesis in organ culture has been investigated using human benign prostatic hyperplasia. From a study of the variables affecting the reproducibility, sensitivity and specificity of the method a simple technique was adopted. This method was applied to the study of the hormone-sensitivity of breast tumours, some of which showed a dose-response to 17 beta-estradiol. The criteria which must be applied to make such a test of clinical value are discussed.