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The crystal structures of the rhombohedral compounds ACrX 2 (A = Na, Ag, Cu; X = S, Se) at 300 and 4 K have been refined from neutron-diffraction powder data. The structures are based on cubic close-packings of the anions with Cr in half of the octahedral holes, so that CrX2 sandwiches are formed. Na occupies the octahedral holes between these sandwiches, Ag and Cu half of the tetrahedral holes; Ag and Cu have anomalously large (and anisotropic) thermal parameters, probably indicating a statistical distribution of these atoms around their average positions. The Ag and Cu compounds undergo reversible phase transitions at 397°C (AgCrS 2 ), 402°C (CuCrS 2 ), or 202°C (AgCrSe 2 ); in the high-temperature forms the Ag and Cu atoms are randomly distributed over all tetrahedral holes between the CrX 2 sandwiches. The magnetic structures of NaCrS 2 , NaCrSe 2 , and AgCrSe 2 at 4.2 K have been determined by neutron diffraction. The magnetic moments of Cr 3+ (about 15 % less than the spin-only value) are perpendicular to the c axis. The moments in pseudohexagonal (110) planes are collinear, spins at a distance (−⅓,⅓,⅓) being antiparallel, spins at a distance (⅓, −⅓,⅔) parallel. The spins in adjacent (110) planes make angles , where , = 0° for NaCrSe 2 , = 14° for AgCrSe 2 , = 33° for NaCrS 2 . Thus, NaCrSe 2 2 consists of ferromagnetic layers perpendicular to c, the spins in adjacent layers being antiparallel. In NaCrS 2 and AgCrSe 2 the layers are helimagnetic. These magnetic structures and those of KCrS 2 and LiCrS 2 are discussed in terms of antiferromagnetic direct Cr-Cr interactions and ferromagnetic Cr-X-Cr interactions between Cr neighbors in the layers; the former interaction predominates for small, the latter for large Cr-Cr distances.

Summary 1. Sequential studies of serum 5′-nucleotidase (EC 3.1.3.5) in association with other enzymes in patients with malignant diseases are presented. 2. Evidence is given for the specific significance of the assay of 5′-nucleotidase in serum which is a sensitive monitor for the appearance of metastases in liver. 3. The clinical and biochemical aspects of 5′-nucleotidase assays and other liver function tests are discussed.

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A randomized clinical trial of nafoxidine, a non-steroidal oestrogen antagonist, and ethinyloestradiol in postmenopausal patients with advanced breast cancer produced objective remissions in 31% of 49 women receiving nafoxidine and in 14% of 49 receiving ethinyloestradiol. The differences in remission rates was almost significant (0.05 less than P less than 0.10). Life-threatening complications were more frequent with ethinyloestradiol than with nafoxidine but the latter produced specific toxic reactions on skin and hair that may limit its practical usefulness. Synthetic oestrogen antagonists may occupy a privileged place in the treatment of breast cancer, and other representatives of this new class of compounds should be accurately assessed in randomized clinical trials.

Plasma-prolactin was assayed in 115 patients with breast cancer and 115 matched controls. Mean plasma-prolactin levels were 6.0 ± 3.7 ng. per ml. and 5.9 ± 2.9 ng. per ml., respectively. Plasma-prolactin levels were normally distributed in both groups. Plasma levels in 64 members of nine families with a high frequency of breast cancer were irregularly distributed, with a mean prolactin level of 10.4 ± 8.1 ng. per ml. Statistical evaluation demonstrated that breast-cancer patients and controls may be regarded as one population but that the prolactin levels in the high-risk group represent a different population (P

Approximately 1/3 of all mammary carcinomas are hormone-dependent. Therefore in approximately 30% of these cancer patients transient regression of the tumor may be obtained by means of endocrine therapy. Ablative procedures such as ovariectomy, adrenalectomy, hypophysectomy, roentgen castration, and destruction of the hypophysis by isotope implantation have been used. Administration of such hormones as estrogens, androgens, and corticosteroids and of hormone antagonists have been attempted. Remissions have been observed under the influence of L-dopa. A method to determine the hormone dependency of a mammary tumor is now available. The presence of estrogen receptors in human mammary carcinomas has a distinct correlation with the response to adrenalectomy. In the absence of receptors the chance of success of hormone therapy is minimal. Currently 51 patients have been found suitable for analysis. Remissions occurred in 21 of 24 patients with receptor-positive tumors but in only 3 of 27 with receptor-negative tumors. It was noted that those with cutaneous metastases more often respond favorably to endorcrine therapy than do those with skeletal or visceral metastases. No complete parallelism was found between hormone dependency and the presence of receptors. In 2 of the 3 receptor-positive patients who did not show an objective remission, a distinct subjective remission was noted. It is recommended that receptor determinations be done in every mammary tumor case operated on in the primary stage.

SummaryThe possible relationship between antihemophilic globulin (Factor VIII) and fibrinolysis was investigated. No conclusive evidence about the role of fibrinolysis in the deterioration of AHF was obtained but the findings were more against than in favour of the role of fibrinolysis.

A method is given for determining the general formula UO2+x, of sintered uranium dioxide pellets and uranium dioxide powders. Uranium(VI) is reduced by titration with iron(II) ammonium sulphate, after which the total amount of uranium is oxidized by titration with potassium dichromate. The end-points of both titrations are detected electrometrically. Determination of x in the range 0.0001–1.00 is possible.

A description is given of the accurate determination of small quantities of oxygen, carbon and water in inorganic compounds. Oxygen and carbon are determined by a conductimetric technique and water by a coulometric technique. The limits of detection of the different methods are: 0.1 microg of oxygen, 0.1 microg of carbon and 0.03 microg of water. This is accomplished by taking special care to obtain a low blank and by using stable instruments. A suggestion is made for the simultaneous determination of water and hydrogen.