The effects of corticosteroids on immunoregulation in sarcoidosis.

The effects of in vivo hydrocortisone administration on the kinetics and functional capabilities of cells involved in the immune response in sarcoidosis were examined. Untreated sarcoidosis patients have a decrease in the absolute numbers of circulating T lymphocytes (P < 0.05). However, with regard to the proportions of T lymphocyte subpopulations, there is an increase in the relative proportions of IgG Fc receptor positive T cells (T_G) (P < 0.01), which have suppressor capabilities in certain in vitro systems of mitogen-induced antibody production, and a relative decrease in IgM Fc receptor positive T lymphocytes (T^M) which have helper effects in this system (P < 0.05). Additionally, sarcoidosis patients have circulating “suppressor” monocytes capable of suppressing anti-sheep red blood cell (SRBC) plaque-forming cell (PFC) responses by pokeweed mitogen (PWM)-stimulated lymphocytes. The in vitro removal of this cell abrogated this depressed response (P < 0.01). Intravenous administration of hydrocortisone produced a transient absolute T lymphocytopenia (P < 0.01) accompanied by a relative increase in T^G cells (P < 0.01) and a relative decrease in T_M cells (P < 0.02). Four hours after hydrocortisone therapy, at the point of maximal hydrocortisone-induced monocytopenia (P < 0.01), the suppressed ability of sarcoidosis lymphocytes to synthesize and secrete in vitro anti-SRBC antibody after polyclonal activation was corrected (P < 0.01), and PFC responses comparable to those seen in untreated normal subjects were obtained. These studies demonstrate that corticosteroid administration has profound effects on certain in vitro demonstrable immunoregulatory abnormalities in sarcoidosis.     

Ascaris sp.: water loss during desiccation of embryonating eggs

The ability of embryonating eggs of Ascaris lumbricoides to avoid desiccation by reducing the loss of water through the egg shell was investigated. When exposed to desiccation the eggs lost water at a rate dependent upon the relative humidity and ambient temperature, eventually resulting in the collapse of the eggs and the death of the enclosed embryo. The eggs are small with a large surface to volume ratio. A low permeability to gaseous exchange thus restricts water loss while still ensuring an adequate supply of oxygen for embryonic development. Relative humidity did not appear to affect the rate of development. In eggs exposed to desiccation at various constant temperatures, the rate of water loss increased as an exponential function of increasing temperature. When eggs were exposed to various temperatures before exposure to desiccation at 22 C, the rate of water loss increased as a function of increasing pretreatment temperature. After exposure to 63–65 C, the ability of the egg shell to slow down the loss of water was destroyed. These phenomena suggest that there is not a simple “critical” or “transition” temperature, but a gradual melting of the complex mixture of components forming the lipid layer.     

Les Cricetidae (Rodentia,Mammalia)de la Milloque (bassin d'Aquitaine): Horizon repère de l'Oligocène supérieur

A screen washed and hand sorted sample of six tons sediments from La Milloque (Lot-et-Garonne) has yielded to the author several thousand micromammal's teeth. Among the Rodents, four extinct species of Cricetids have been recognized: Eucricetodon praecursor (Schaub, 1925); Adelomyarion viretiHugueney, 1969; Pseudocricetodon cf. thaleri (Hugueney, 1969); Melissiodon quercyiSchaub, 1920. The fossil remain's study affords many paleontological informations more particularly for E. praecursor, a previously poorly known species. About the upper Oligocene biochronology the four species' evolution degrees prove the statute of reference locality attributed to La Milloque, «mammalian timemark just below the reference locality of Coderet (Allier). Moreover it's pointed out that the locality of Rickenbach (Switzerland) is slightly older than La Milloque, whereas an intermediate age between La Milloque and Coderet can be suggested for the locality of Dicupentale (Tarn-et-Garonne).