Transformation-induced alterations in adhesion. Binding of pre-formed cell aggregates to cell layers

Male and female college students were shown videotapes of supposed male offenders describing the details of thefts they had committed. Videotaped sequences were varied so that offenders were 9 to 10 years old or of college age. Also, actors varied in their mode of emotional self-presentation. Comparisons of punishments suggested by subjects indicated that joyful actors received the highest level of punishment while distressed offenders received the lowest level of suggested punishment. It was also found that the emotions of children exerted a greater persuasive effect on subjects' ratings than did the emotions of adults although the pattern of results was similar across ages. These results were discussed as demonstrating that the age and emotion of an offender can exert considerable influence on the attribution of blame made by a disciplinarian.     

A Refinement Strategy for Circus

We present a refinement strategy for Circus, which is the combination of Z, CSP, and the refinement calculus in the setting of Hoare and Hes unifying theories of programming. The strategy unifies the theories of refinement for processes and their constituent actions, and provides a coherent technique for the stepwise refinement of concurrent and distributed programs involving rich data structures. This kind of development is carried out using Circuss refinement calculus, and we describe some of its laws for the simultaneous refinement of state and control behaviour, including the splitting of a process into parallel subcomponents. We illustrate the strategy and the laws using a case study that shows the complete development of a small distributed program.     

Xenogeneic spermatogenesis following transplantation of hamster germ cells to mouse testes

It was recently demonstrated that rat spermatogenesis can occur in the seminiferous tubules of an immunodeficient recipient mouse after transplantation of testis cells from a donor rat. In the present study, hamster donor testis cells were transplanted to mice to determine whether xenogeneic spermatogenesis would result. The hamster diverged at least 16 million years ago from the mouse and produces spermatozoa that are larger than, and have a shape distinctly different from, those of the mouse. In four separate experiments with a total of 13 recipient mice, hamster spermatogenesis was identified in the testes of each mouse. Approximately 6% of the tubules examined demonstrated xenogeneic spermatogenesis. In addition, cryopreserved hamster testis cells generated spermatogenesis in recipients. However, abnormalities were noted in hamster spermatids and acrosomes in seminiferous tubules of recipient mice. Hamster spermatozoa were also found in the epididymis of recipient animals, but these spermatozoa generally lacked acrosomes, and heads and tails were separated. Thus, defects in spermiogenesis occur in hamster spermatogenesis in the mouse, which may reflect a limited ability of endogenous mouse Sertoli cells to support fully the larger and evolutionarily distant hamster germ cell. The generation of spermatogenesis from frozen hamster cells now adds this species to the mouse and rat, in which spermatogonial stem cells also can be cryopreserved. This finding has immediate application to valuable animals of many species, because the cells could be stored until suitable recipients are identified or culture techniques devised to expand the stem cell population.