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Ovine placental lactogen, purified from term sheep cotyledons, has been found to have chemical and biologic properties similar to those of human placental lactogen, ovine growth hormone, and ovine prolactin. OPL stimulates lactation in vivo and in vitro and binds to prolactin and growth hormone membrane receptors. Its binding to growth hormone receptors is approximately 20 times greater than that of hPL, suggesting that its somatotrophic potency is greater than that of hPL. Preliminary in vivo studies in the sheep indicate that oPL affects maternal carbohydrate, lipid, and protein metabolism and that its effects are, in part, similar to those of hPL and growth hormone.

To determine the range over which cytosolic Ca2+ concentration (Cai2+) is regulated, Cai2+ was measured in salivary acini loaded with Fura-2. With extracellular Ca2+ (Cao2+) = 2.5 mM, mean resting Cai2+ (+/- SD) was 103 +/- 20 nM (n = 29). Carbachol increased Cai2+ immediately to 288 +/- 81 nM, which then declined to a sustained level of 253 +/- 58 nM. When Cao2+ was less than 10 nM, the immediate response to carbachol was little affected but the sustained response was abolished. Atropine abolished all responses to carbachol. Changes in Cai2+ were not due to Ca2+-induced Ca2+ release or to Ca2+ influx via voltage-dependent channels. With Cao2+ = 2.5 mM, epinephrine raised Cai2+ initially to 196 +/- 57 nM (n = 6), which soon declined to stable levels of 178 +/- 40 nM. When Cao2+ was less than 10 nM the prolonged response to epinephrine was abolished but the initial increase was relatively unaffected. All epinephrine-induced changes in Cai2+ were abolished by prazosin. The range of Cai2+ measured corresponds to that over which non-mitochondrial Ca2+ transport is stimulated in permeabilized submandibular gland acini suggesting that such a Ca2+ transport system may regulate physiological changes in Cai2+ in these acini in the rat.

To determine the effects of exposure to reserpine on subcellular Ca2+ transporting systems, active Ca2+ uptake was measured with and without ruthenium red in submandibular gland vesicles obtained from rats after chronic treatment with reserpine. The properties of ruthenium red-sensitive Ca2+ uptake were similar to those measured in submandibular gland vesicles from untreated rats: it was abolished by the dye, was relatively low at 1 microM Ca2+ but increased markedly at millimolar Ca2+ levels and was positively and significantly correlated with the mitochondrial membrane marker, cytochrome-C oxidase activity, in membrane subfractions obtained by differential centrifugation (r = 0.67, p = 0.0005, n = 29). On the other hand, ruthenium red-insensitive Ca2+ uptake, though stimulated at submicromolar Ca2+ concentrations, was reduced by a mean of 54% compared to preparations from untreated animals and particulate RNA content was 18% of that found in control preparations. Moreover, the distributions of ruthenium red-insensitive Ca2+ uptake and particulate RNA (which are closely correlated in vesicles from untreated rats) were not significantly related when measured in vesicles of submandibular glands from reserpine treated rats. Other membrane markers and overall membrane protein content were not significantly altered after chronic reserpine exposure. We conclude that reserpine treatment has little effect on mitochondrial Ca2+ uptake capacity but abolishes or drastically reduces the high affinity Ca2+-sequestering activity which, in submandibular gland vesicles from untreated rats, is apparently associated with the endoplasmic reticulum.

Ovine placental lactogen (oPL) and bovine growth hormone (bGH) increase the circulating concentration of somatomedin in hypophysectomized rats. This finding indicates that some of the somatotropic properties of oPL may be due to the induction of somatomedin and raises the possibility that oPL has a role in the control of fetal growth.

Active Ca2+ transport was studied in acini that had been permeabilized by incubation in buffer nominally free of Ca2+ in order to avoid any contribution to measured Ca2+ uptake by elements of the plasma membrane. In most experiments, ruthenium red was used to inhibit mitochondrial Ca2+ uptake. Non-mitochondrial Ca2+ transport was greatest at pH 7.0-7.5 and required Mg2+-ATP at concentrations typical of the cytosol (K0.5 = 1.36 +/- 0.53 mM). Other substrates were much less effective than ATP. Ca2+ uptake was stimulated by Ca2+ at concentrations near those measured in intact cells (K0.5 = 0.43 +/- 0.17 microM). Hill coefficients at subsaturating concentrations of Ca2+ (1.08 +/- 0.27) and Mg2+-ATP (0.81 +/- 0.22) indicated that cooperative interactions are not characteristic of the major cationic regulators of Ca2+ transporting activity. Na+ did not release Ca2+ from acinar mitochondria, but consistently reduced non-mitochondrial Ca2+ uptake by about 20% as compared to uptake in the presence of an equimolar K+ concentration. The properties of non-mitochondrial Ca2+ uptake in permeabilized acini are similar to those of high affinity Ca2+ uptake which, in broken cell preparations, has been found distributed in parallel with elements of the endoplasmic reticulum. The Ca2+-sequestering properties of a non-mitochondrial organelle in permeabilized submandibular gland acini are those expected of a principal regulator of cytosolic Ca2+ and could account for the ionized Ca2+ concentration measured in resting salivary acinar cells.

The Technicon SMAC system was adapted to function with much smaller volumes of plasma than those used in standard procedures. With only minimal operator-entered changes to the 7.6 computer program, and simple modifications of the glucose and alkaline phosphatase channels, the SMAC analyser performed equally well when the plasma volume was decreased from 235 microliter sequentially down through 176 microliter, 142 microliter, and 105 microliter. The basic principle employed was to maintain a constant flow rate of diluted sample plus diluent with decreasing sample size. The instrument proved to have the capability of operating successfully on all channels with lower signals than those encountered with the unmodified system.

The isolation and characterization of the title antibiotics, which are produced by the same Streptomyces sp., is described. The potent antitumor agent, PD 124,895, is an analog of hydroxyelactocin (PD 114,721). PD 124,966 is a new member of the depsipeptide family of antibiotics.

Two patients with multiple myeloma died in acute liver failure. Both had been treated with the anabolic steroid oxymetholone and both subsequently developed severe cholestatic hepatitis. In one the histological lesion progressed despite cessation of oxymetholone therapy. Myeloma infiltration of the liver and peliosis hepatis were not seen. As a fatal outcome from cholestatic hepatitis due to oxymetholone is rare it is possible that an unknown potentiating factor is present in multiple myeloma that can lead to a fatal outcome. If oxymetholone therapy is to be used in such patients then close clinical and laboratory assessment of liver function should be carried out in an attempt to prevent this unusual and fatal complication.

The structure of D-xylose isomerase from Streptomyces rubiginosus has been determined at 4-A resolution using multiple isomorphous phasing techniques. The folding of the polypeptide chain has been established and consists of two structural domains. The larger domain consists of eight beta-strand alpha-helix (beta alpha) units arranged in a configuration similar to that found for triose phosphate isomerase, 2-keto-3-deoxy-6-phosphogluconate aldolase, and pyruvate kinase. The smaller domain forms a loop away from the larger domain but overlapping the larger domain of another subunit so that a tightly bound dimer is formed. The tetramer then consists of two such dimers. The location of the active site in the enzyme has been tentatively identified from studies using a crystal grown from a solution containing the inhibitor xylitol.

Eighty-six adults with malignant disease were given high doses of methotrexate with folinic acid rescue, with acceptable toxicity. Protocal violations in two cases led to death. The results of therapy in some diagnostic groups are encouraging.

A search for specific placental lactogen binding was undertaken in tissues obtained from late pregnant rabbits using the placental lactogens from sheep, cows, and human beings. 125I-labeled ovine lactogen exhibited highest specific binding to the adrenal gland (57.8%), followed by liver (21.5%), ovary (19.9%), mammary gland (15.9%), uterus (12.2%), kidney (8.8%), brain (8.5%), and adipose tissue (7.9%). In liver and mammary gland, the displacement curves for ovine and human lactogen were identical to that for bovine prolactin, indicating that they share the same receptor site. Although the displacement curve for bovine lactogen was parallel to that of the other lactogens the bovine hormone is less active in the radioreceptor assay.

A complex of structurally related compounds that exhibit in vivo antileukemic activity was isolated from fermentation broths of a new streptomycete. The components of this complex are water soluble phosphate esters containing a conjugated triene system. The isolation and characterization of three of these components are described.

Explants of human chorion-decidual tissue obtained at delivery from normal, full-term pregnancies synthesize and secrete prolactin. This hormone is indistinguishable from pituitary prolactin by chromatographic, electrophoretic, immunologic, and receptor assay techniques. These results suggest that chorion-decidua may be the source of the large quantities of prolactin in amniotic fluid.

The intravenous administration of ovine placental lactogen to pregnant and non-pregnant sheep produced significant acute decreases in plasma free fatty acid, glucose and amino nitrogen concentrations. Plasma insulin concentrations decreased 1 h after administration of ovine placental lactogen and then increased significantly above baseline concentrations. The results suggest that, like human placental lactogen, ovine placental lactogen is important in the modulation of intermediary metabolism during pregnancy. The sheep is an excellent animal model for the investigation of the physiology of placental lactogen.

Creation of an artificial subcutaneous arteriovenous fistula was attempted in five patients with malignant haematological disorders (two with Hodgkin's disease, two with acute lymphatic leukaemia, and one with acute myeloid leukaemia). The average time from the start of treatment to attempted creation of the fistulae was four years. Neither direct arteriovenous anastomosis nor an interposition mandril graft was successful in any patient. Failure was attributed to impaired venous run-off secondary to previous episodes of thrombophlebitis induced by the intravenous administration of cytotoxic drugs. The use of an arteriovenous fistula early in the course of the disease might minimize these later problems.

Arginine has been demonstrated to be a potent stimulus to GH and PRL secretion. To determine the effect of arginine on plasma ovine placental lactogen (oPL) concentrations, arginine (50 g in 350 ml distilled water, pH 7.4) or hypertonic saline of identical volume, osmolality, and pH was infused iv over a 30-min period into nine pregnant ewes, and blood samples from chronic indwelling venous catheters were obtained at frequent intervals before and for 8 h after the infusions. After the infusion of hypertonic saline, plasma oPL concentrations (measured by homologous RIA) decreased 20--50% over 1--2 h and then returned to baseline concentrations. After the infusion of arginine, plasma oPL concentrations also decreased by 20--50% for 1--2 h. However, 2--3 h after the infusion, plasma oPL concentrations in creased 79--115% (delta = 204--700 ng/ml) over preinfusion concentrations in seven ewes and 454% (2930 ng/ml) and 1142% (2042 ng/ml) in two ewes and remained elevated for the remainder of the 8-h interval. When the amount of arginine infused was reduced from 50 to 25 g, an increase in plasma oPL concentrations occurred in only one of five ewes. Plasma oPL concentrations increased by 8--58% after infusions of 50 g alanine or glycine but did not increase after 50 g glutamic acid. The delayed oPL response to arginine suggests that the increase in plasma oPL concentrations is not caused directly by arginine but rather by changes in the synthesis, secretion, and/or degradation of oPL induced indirectly by arginine.

Energy-dependent Ca2+ uptake was characterized in vesicles derived from rat submandibular salivary glands. Ca2+ transport was stimulated by submicromolar levels of Ca2+, reached a plateau at 1-20 microM Ca2+ then again increased as the Ca2+ concentration rose to millimolar levels. Ruthenium red (2.5 microM) was used to resolve this pattern of uptake into two components: ruthenium red-insensitive Ca2+ transport occurs in the presence of the dye, is stimulated by submicromolar Ca2+ concentrations and reaches a maximum steady state at about 1 microM Ca2+. The distribution of ruthenium red-insensitive Ca2+ uptake in membrane subfractions obtained by differential centrifugation is positively (r = 0.717) and significantly (p = 0.001) correlated with the distribution of membrane-bound RNA in the same subfractions. Ca2+ uptake which is abolished by ruthenium red is greatest at millimolar Ca2+ concentrations. Its distribution is positively (r = 0.828) and significantly (p = 0.0001) correlated with the cytochrome-c oxidase activity of the membrane subfractions but is unrelated to the distribution of particulate RNA and is negatively correlated with Na+-K+ ATPase activity. We conclude that vesicles derived from the endoplasmic reticulum of rat submandibular glands actively transport Ca2+ by a ruthenium red-insensitive mechanism which is stimulated at Ca2+ concentrations typical of the cytosol. Membranes derived from mitochondria also sequester Ca2+ but by a mechanism which is inhibited by ruthenium red and which reaches its maximum steady state capacity at relatively high Ca2+ concentrations.

Angiotensin converting enzyme was measured in the serum of 52 patients with sarcoidosis, 67 healthy control subjects and 64 patients with pulmonary and non-pulmonary diseases. The patients with sarcoidosis were classified on clinical grounds as having active or inactive disease. In 26 patients with active sarcoidosis not taking corticosteroids the mean serum ACE was significantly higher than in normal controls (P less than 0 . 001). 73% of these patients had elevated serum ACE. Only two out of 12 (17%) patients with inactive sarcoidosis not taking corticosteroids had elevated serum ACE. Serum ACE was normal in patients taking oral corticosteroids for longer than two weeks. Eighty per cent of patients with active sarcoidosis with radiological evidence of pulmonary parenchymal involvement had an elevated serum ACE compared to 25% in patients with normal chest X-rays and 60% of those with bilateral hilar lymphadenopathy. All sarcoid patients with hypercalcaemia had elevated serum ACE whereas only half of those with normal serum calcium had elevated ACE. In the patients with other thoracic and granulomatous conditions serum ACE was normal or rarely marginally elevated. Serum ACE appears to be of value in the diagnosis of active sarcoidosis.

CD45 is a family of high molecular weight leukocyte cell surface glycoproteins. Recently, two related subregions of the cytoplasmic domain of CD45 have been shown to have 30-40% amino acid identity with a human placental protein phosphotyrosine phosphatase, and CD45 isolated from human spleen was found to exhibit intrinsic protein phosphotyrosine phosphatase (EC 3.1.3.48) activity. In the present studies, we demonstrate that each of the known isoforms of murine CD45 has an equivalent basal level of protein phosphotyrosine phosphatase activity and establish that this enzymatic activity is associated with the cytoplasmic domain of the glycoprotein. Studies with three independent sets of well-characterized parental CD45+, mutant CD45-, and revertant CD45+ lymphoma cell lines indicate that loss of CD45 increases the phosphorylation of the src-related leukocyte-specific tyrosine protein kinase p56lck on tyrosine-505, a putative negative regulatory site. This suggests that CD45 may play a role in leukocyte growth regulation by altering the kinase activity of p56lck.

Energy-dependent subcellular Ca2+ sequestration was studied in the presence of ruthenium red using rat pancreatic acini, which had been permeabilized by exposure to medium nominally free of Ca2+. The initial rate of Ca2+ uptake (approximately 2,800 pmol.min-1.mg acinar protein-1) quickly slowed, and a mean steady-state Ca2+ content of approximately 3,000 pmol/mg was reached after 5-10 min of incubation at 37 degrees C. Ca2+ uptake was stimulated by submicromolar Ca2+ concentrations (K0.5 = 156 nM); required Mg2+-ATP (K0.5 = 0.78 mM) was greatest at a pH of 7.0 and was abolished by the Ca2+ ionophore A23187. Other nucleotide phosphates as well as p-nitrophenylphosphate were relatively poor substrates, supporting Ca2+ uptake at initial rates that were 6-14% of those measured in the presence of ATP. These results show that pancreatic acini permeabilized without detergents possess a nonmitochondrial Ca2+ transporting system not located in the plasma membrane but with the properties expected of a major regulator of acinar cytosolic Ca2+ concentration.