Applications of the 1-D diffusion approximation to the optics of tissues and tissue phantoms

Optical constants of animal and plant tissues were measured over a wide spectral range using an integrating sphere spectrophotometer. The data were analyzed with two formulations of the 1-D diffusion approximation differing in the phase function. The accuracy of the similarity transformation was examined with tissue phantoms incorporating known chromophores in light scattering media.

Clinical manifestations and diagnosis of acute pyrethroid poisoning

This article reviews 573 cases of acute pyrethroid poisoning reported in the Chinese medical literatures during 1983-1988. There were 325 cases of acute deltamethrin poisoning (occupational 158, accidental 167), 196 patients of acute fenvalerate poisoning (occupational 63, accidental 133, including 2 cases of ingestive fenvalerate-organophosphate mixture poisoning), 45 cases of acute cypermethrin poisoning (occupational 6, accidental 39) and 7 cases of other pyrethroid poisoning (occupational 2, accidental 5). The clinical manifestations have been reviewed and analysed. The diagnosis, gradation and differential diagnosis of occupational acute pyrethroid poisoning have been discussed.

Observation of high-order degenerate wave mixing in BaTiO(3)

We report for the first time to our knowledge some phenomena of high-order degenerate wave mixing observed in a BaTiO(3) crystal when self-pumped phase conjugation occurs. Applications of these phenomena are discussed.

Selective control of rat granulosa cell inhibin production by FSH and LH in vitro

We studied the role of luteinising hormone (LH) and human chorionic gonadotropin (hCG) in regulation of rat granulosa cell inhibin production. Whereas pregnant mare serum gonadotropin (PMSG) or purified rat follicle-stimulating hormone (FSH) stimulated inhibin accumulation in culture media up to 6-fold in a dose-dependent manner, hCG or LH alone were without significant effect. Concomitant addition of hCG or LH to cultures containing half maximal or maximal stimulating concentrations of PMSG did, however, result in a dose-dependent inhibition of PMSG/FSH-induced inhibin production. However, in the 2-step culture system a biphasic effect of hCG treatment on FSH-primed granulosa cell inhibin and progesterone production was evident. hCG was only inhibitory when the cells in the 2-step system were primed with PMSG. These data indicate that granulosa cell inhibin production is under direct control of both FSH and LH, and provide a possible explanation for alterations in inhibin activity around the time of ovulation in vivo.

Phosphorylation of platelet actin binding protein protects against proteolysis by calcium dependent sulfhydryl protease

When Actin Binding Protein (ABP) isolated from human blood platelets is phosphorylated in vitro with a cyclic AMP dependent kinase it becomes resistant to proteolysis by the Calcium Dependent Sulfhydryl Protease (CDSP). This protection against proteolytic cleavage is specific for CDSP since phosphorylation of ABP does not protect against proteolysis by trypsin, papain and thermolysin. Thus, there appears to be a distinct phosphorylation site on the ABP molecule which is essential for regulating the initial proteolytic degradation of ABP by CDSP.

Peptic fragments of bovine serum albumin bind antigen-specific T suppressor cells from orally tolerized mice

The antigenic structures capable of binding immunoregulatory T cells have been investigated. The functional properties (suppression or help) of BSA-specific T cells from primed or orally tolerized mice with capacity to adhere to bovine serum albumin or its peptic fragments were examined in reconstitution experiments in which splenic T-cell populations together with naive B cells were transferred into irradiated syngeneic recipients. Antigen-specific T suppressor cells isolated from mice tolerized to BSA adhered to peptic fragments of BSA as well as to the intact antigen. BSA-specific T helper cells adhered only to the intact antigen. Our data suggest that the preferential activation of T suppressor cells following administration of peptic fragments may be due to their ability to adhere to such fragments. These findings offer a novel approach of separation and identification of T suppressor cells and may be useful in further studies of immunosuppression.