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Antithrombin III-heparin cofactor has been isolated from normal rat plasma, purified to homogeneity on acrylamide gel electrophoresis and used to prepare a monospecific antiserum in rabbits. Measurements of rat antithrombin III were made by a single radial immunodiffusion assay. Net synthesis of antithrombin III was investigated during 12- or 24-h perfusions of the isolated rat liver. In perfusions performed under basal conditions cumulative synthesis of antithrombin-III was observed to occur at a rate sufficient to replace the total circulating plasma antithrombin III in about 6 h. In perfusions performed under full supplementation conditions which greatly enhanced synthesis of fibrinogen and alpha-2 (acute-phase) globulin (known acute-phase reactant proteins) net synthesis of antithrombin III was not significantly greater than that observed in control perfusions. Although these prolonged perfusion studies conclusively demonstrate net synthesis of antithrombin III by the isolated rat liver, they afford no evidence that this protein is an acute-phase reactant.

Iron (totalling 7.5 mg per mouse in three doses) was injected into hairless mice to determine the relationship between skin pigmentation and hemosiderin deposition. The skin color reached its maximum 24 to 48 hours after the last injection and then gradually faded over the subsequent 8 months. In the skin, hemosiderin granules were present extracellularly between collagen bundles as well as within dermal macrophages, Langerhans cells and indeterminate dendritic cells of the epidermis. A larger amount of iron was deposited in the facial than in the dorsal skin, resulting in darker pigmentation of the former. This study suggests that brownish discoloration of skin in hemochromatosis might be attributable in some degree to accumulation of hemosiderin and that pronounced hyperpigmentation of the face in hemochromatosis might be due to increased activation of melanocytes by a high content of hemosiderin.

A highly potent heparin (Heparin Schering) was characterized in comparison to commercial heparin by affinity chromatography on antithrombin-III-sepharose. Heparin Schering consists of 83% high affinity and 17% low affinity fractions, whereas commercial heparin contained only 40% high affinity heparin and 60% low affinity heparin. The specific biological activities per microgram uronic acid and elution pattern on antithrombin-sepharose of high affinity heparin fraction were similar for both heparin preparations. It is concluded that the 2 times more potent anticoagulant activity of heparin Schering is mainly due to the enrichment of high affinity fraction (83%), which is also present in commercial heparin but at a remarkably lower percentage (40%).

The cytoplasmic concentrations of ER, AR, PR, and GR were determined in 124 specimens of normal and abnormal endometrium and other uterine human tissues by the DCC technique. In the endometrial carcinoma group, we observed that pretreatment with MAP leads to low cellularity, higher amount of AR, lower amounts of detectable ER, GR, and PR: the last receptor was almost always absent. A positive correlation between ER presence and tumor grade of differentiation was found in endometrial tumors from hormone-untreated patients. With the value of 142 fmol/mg DNA as the cut off point between high and low binding capacity, the frequency of the single receptors within the hormone-untreated cancer group ranged from 61% to 88%; ER and PR were simultaneously present in 55% of cases (they are tightly correlated in the different biopsies with respect to frequency and amount); ER-AR-PR were present in 45% and all the four receptors in 40% of cases. Slightly higher values were found in normal endometrium collected from hormone-untreated patients.

A 51chromium (51Cr)release microcytotoxicity assay has been established for studying cell-mediated immunity in chickens to a potentially wide variety of antigens. The system investigated in detail uses thyroglobulin-coated chicken red blood cells (Tg-CRBC) to analyse effector cell mechanisms operative in spontaneous autoimmune thyroiditis in Obese strain (OS) chickens. A variety of technical parameters were investigated in order to optimise reliable, reproducible target cell preparation and to minimise spontaneous 51Cr-release. The final method adopted used tannic acid for coupling antigen to carefully selected donor erythrocytes of uniform MHC genotype. For the study of antibody dependent, cell-mediated cytotoxicity, Tg-CRBC were pre-sensitised with OS serum containing high titre Tg-autoantibody. Tannic acid-treated CRBC (TA-CRBC) served simultaneously as controls for the Tg specificity of direct cellular cytotoxicity (DCC) to Tg-CRBC, and also as target cells for natural, or spontaneous cellular cytotoxicity (SCC). With such an assay, cells capable of mediating Tg-specific DCC were demonstrated in the OS, but not in normal chickens. No differences in ADCC or SCC were observed when the two strains were considered as a whole, i.e. regardless of age, sex, MHC genotype or extent of disease.

The displacement of the phenolic OH-group of diethylstilbestrol into the 3,3'-position (trans-3,3'-dihydroxy-alpha, beta-diethylstilbene, compd. III) leads to a strong decrease of the estrogenic effect under conservation of the receptor affinity. In vitro, III inhibits the estradiol-receptor-interaction competitively and, in vivo, antagonises the uterotropic effect of estrone in the mouse. In tests with the DMBA-induces, hormone-dependent mammary carcinoma of the rat a dose-dependent strong decrease of tumor size and yield is achieved under the influence of III, due to the antiestrogenic properties of III. The replacement of the alpha, beta-bound ethyl groups in III by other alkyl chains leads to no further increase of the antiestrogenic and antitumor activity.