Daphnia size structure,vertical migration,and phosphorus redistribution

The timing and magnitude of diel migration in two daphnid assemblages were determined from a series of vertical profiles of daphnid size distribution. Animals were collected concurrently for gut fullness determination. Only large daphnids (> 1.4 mm) migrated, but these animals could account for substantial vertical and diel differences in phosphorus excretion rate. Gut fullness measurements and time courses of diel vertical migration suggested that large Daphnia can cause a net downward flux of phosphorus during summer in thermally stratified lakes.     

Influence of Hydrocortisone on Chick Embryo Retina Development

Treatment of chick embryos in ovo with hydrocortisone-21-phosphate (a single dose of 150 micrograms) caused a marked reduction of retinal thymidine kinase activity 24 h later. The inhibitory effect was highest (65-70%) in 8-10-day-old embryos and declined with age, disappearing after day 15. It was accompanied by a reduction in thickness of the retinal layers. Adrenocorticotropic hormone (ACTH) treatment (10 micrograms daily for 2 days) also produced an age-dependent inhibitory effect on retinal thymidine kinase, whereas treatment with a single dose of 200 micrograms of metopirone, a compound that prevents the 11 beta-hydroxylation of steroid molecules in the adrenal glands, impeded the decrease in thymidine kinase activity that normally occurs in chick embryo retina after day 9 of development. In addition, metopirone prevented the inhibition exerted by ACTH on thymidine kinase activity but had no effect on the action of hydrocortisone.     

Successful pregnancy in a woman with congenital factor XIII deficiency treated with substitutive therapy. Report of a second case

A syndrome of marked fetal wastage is associated with congenital factor XIII deficiency in adult women. A previously unreported case of a woman with factor XIII deficiency is described, in which substitutive treatment with normal plasma or placental factor XIII concentrate permitted two normal pregnancies. Factor XIII activity was maintained above 1-2% with intermittent infusion of 300 ml to 450 ml of plasma every 14 days or of 500 units of concentrate every 21 days. This case confirms the only other case so far reported in which factor XIII substitutive therapy was able to permit a normal pregnancy in a woman with factor XIII deficiency and seems to suggest factor XIII to be involved in the process of annidation.     

Modulation of asialoglycoprotein binding activity in livers of pregnant or estrogen-treated rats

This report deals with the modulation of activity and expression of the hepatic asialoglycoprotein receptor, in pregnant or diethylstilbestrol-treated rats.The results show a two-fold increase in the total cell associated binding activity, both in pregnant and in estrogen-treated animals, with respect to normal values. On the contrary the surface expression was shown to be strongly enhanced only in the liver of pregnant rat. Therefore the modulation shown by this receptor system in pregnancy seems to be only partially estrogen-dependent.     

Minor components in food plants--Note I. Flavonol glycosides from Ullucus tuberosus.

This work deals with the isolation and characterization in Ullucus tuberosus of flavonoids, a class of natural products influencing potentially the taste and nutritional value of the plant food. The three flavonoids, rutin, narcissin and kaempferol 3-O-(2",6"-di-O-alpha-L-rhamnopyranosil)-beta-D-glucopyranoside, isolated, are devoid of taste, but appear to possess health promoting effects.     

Ultrastructural analysis of asialoglycoprotein receptor mediated endocytosis in cultured newborn hepatocytes

We examined the receptor-mediated endocytosis of asialoglycoproteins in thick sections of cultured hepatocytes of newborn rats by high voltage electron microscope. The organelles involved in endocytosis are revealed ultrastructurally using colloidal gold particles coupled to lactosylated bovine serum albumin. Keeping the cells at 4 degrees C the marker binds to the cell surface showing microvilli, and is not internalized. Increasing the temperature to 37 degrees C, we observed that within 5-15 min. the marker enters the intracellular endocytic organelles close to the cell surface. After 60 min. the marker is found in the larger and deeper endocytic organelles and in large lisosome-like vesicles. We find that the process of endocytosis in newborn cultured hepatocytes is similar to that found in cultured cells of adult rats, but the process of internalization is slower.     

The Mr 17500 region of the A chain of urokinase is required for interaction with a specific receptor in A431 cells

We have found the existence of specific receptors for the plasminogen activator, urokinase, in A431 human epidermoid carcinoma cells, cultures in plasminogen-free conditions. Two subsets of receptors have been recognized on the basis of 125I-labelled urokinase binding analysis: about 1 X 10(3) high-affinity (Kd = 5.0 X 10(-11) M) and 1 X 10(5) low-affinity (Kd = 9 X 10(-9) M) receptors per cell. The electron microscopic observation of a urokinase: ferritin conjugate has shown single and clustered receptors at the cell surface. Down-regulation of the receptors (T1/2 = 3.77 h) follows the binding of urokinase. The binding does not involve an intact catalytic site and is inhibited by a monoclonal antibody against the Mr 17500 proteolytic fragment of the A chain of urokinase.     

EBNA-negative polyclonal B cells derived from a long-term culture of unclassified acute lymphoblastic leukemia: IL-2-like activity of culture's supernatant

A long-term culture of bone marrow lymphoblasts in a case of unclassified acute lymphoblastic leukemia is described. Cells lacking any lymphocytic marker in the early phase of the culture were gradually substituted by B cells showing a pattern of polyclonality. The culture supernatant contained high levels of immunoglobulins also showing interleukin 2 activity. Search for antigens related to the Epstein-Barr virus was negative. A clonal expansion of B cells versus spontaneous differentiation of unclassified leukemic cells is discussed; the long-term culture technique as a tool for a better evaluation of leukemic cells is suggested and discussed.     

High density lipoproteins during rat liver regeneration

Compositional and maturative parameters of high density lipoproteins (HDL) have been examined during the early stages of rat liver regeneration, when lecithin:cholesterol acyltransferase (LCAT) activity, responsible for the maturation of this lipoprotein class, is markedly decreased. Both HDL subclass distribution and chemical composition are not significantly different from the control, except for a slightly lower cholesterol ester content. Few disc-shaped particles are detectable by electron microscopic observation. Cholesterol ester decrease and presence of immature particles are related, but the entity of the modification is lower than suggested by the deep decrease of LCAT activity. This seems to indicate that proper HDL maturation is assured in the regenerating liver despite low LCAT activity.