Glycosaminoglycan synthesis by mammary tumor spheroids

Multicellular aggregates of tumorigenic mouse mammary epithelial cells contain a hyaluronate-rich matrix, both at the aggregate periphery and within the growing spheroid. It is proposed that the establishment of a hyaluronaterich matrix is essential to spheroid growth in vitro, and that the spheroid is a good model system for analysis of this aspect of early tumor development.     

Two Possibly Distinct Prostaglandin E1 Receptors in N1E-115 Clone: One Mediating Inositol Trisphosphate Formation, Cyclic GMP Formation, and Intracellular Calcium Mobilization and the Other Mediating Cyclic AMP Formation

Prostaglandin E1 (PGE1)-mediated transmembrane signal control systems were investigated in intact murine neuroblastoma cells (clone N1E-115). PGE1 increased intracellular levels of total inositol phosphates (IP), cyclic GMP, cyclic AMP, and calcium ([Ca2+]i). PGE1 transiently increased inositol 1,4,5-trisphosphate formation, peaking at 20 s. There was more than a 10-fold difference between the ED50 for PGE1 at cyclic AMP formation (70 nM) and its ED50 values at IP accumulation (1 microM), cyclic GMP formation (2 microM), and [Ca2+]i increase (5 microM). PGE1-mediated IP accumulation, cyclic GMP formation, and [Ca2+]i increase depended on both the concentration of PGE1 and extracellular calcium ions. PGE1 had more potent intrinsic activity in cyclic AMP formation, IP accumulation, and cyclic GMP formation than did PGE2, PGF2 alpha, or PGD2. A protein kinase C activator, 4 beta-phorbol 12 beta-myristate 13 alpha-acetate, had opposite effects on PGE1-mediated IP release and cyclic GMP formation (inhibitory) and cyclic AMP formation (stimulatory). These data suggest that there may be subtypes of the PGE1 receptor in this clone: a high-affinity receptor mediating cyclic AMP formation, and a low-affinity receptor mediating IP accumulation, cyclic GMP formation, and intracellular calcium mobilization.     

A new simplified assay for larval migration inhibition

, , , and 1992. A new simplified assay for larval migration inhibition. International Journal for Parasitology 22: 1183–1185. A simple method is described for the in vitro detection of substances that impair the motility of third-stage larvae of gastro-intestinal nematodes. The test is based on the ability of larvae to freely migrate through selected mesh sizes of nylon sieves and the reduced ability of larvae to migrate after preincubation with, and in the presence of, substances that inhibit or reduce larval motility.     

Changing Fatty Acid Content of Growth Cone Lipids Prior to Synaptogenesis

The developing mouse was used to assess biochemical changes in membrane lipids during the period when nerve growth cones become synapses. Growth cone particles and synaptosomes were simultaneously obtained from common brain homogenates. Incorporation of the essential fatty acid, docosahexaenoic acid (22:6 omega-3), was correlated with the developmental changes in endogenous fatty acid content of growth cones and synaptosomes. Analysis of endogenous lipid content indicated that, at all ages studied, the growth cones contained more arachidonoyl acyl chains (20:4 omega-6) than did synaptosomes. Before the onset of synaptogenesis, levels of arachidonoyl chains increased and levels of 22:6, oleoyl and linoleoyl chains decreased in synaptosomes. Although stearoyl and palmitoyl (16:0) remained stable in synaptosomes, 16:0 decreased in growth cones. With the exception of 16:0 and 20:4, endogenous fatty acyl content of growth cones and synaptosomes became similar by postnatal day 10, which coincides with the onset of synaptogenesis. When 5-day-old mouse pups were injected intraperitoneally with [3H]22:6, the incorporation into growth cone and synaptosome phospholipids was greatest in phosphatidylethanolamine, followed by phosphatidylserine and phosphatidylcholine. Nominal labeling was present in phosphatidic acid and phosphatidylinositol. Labeling in neutral lipids was less than that of phospholipids, with triacylglycerol incorporating most of the neutral lipid label, followed by diacylglycerol and free 22:6. Only the growth cone fraction contained detectable amounts of 22:6-labeled cholesterol esters. The distribution of 22:6 label in plasma 72 h after injection indicated that approximately 60% of the label was in phospholipids with approximately 40% in neutral lipids and less than 5% in free fatty acids.(ABSTRACT TRUNCATED AT 250 WORDS)     

Activation of microcarrier-attached lymphocytes in microgravity

A technology has been developed to achieve optimal attachment of adhesion-independent lymphocytes to microcarrier beads. The activation of T-lymphocytes by concanavalin A was tested under microgravity conditions in an experiment carried out in space during the first Spacelab Life Science Mission. Activation, measured as the synthesis of deoxyribonucleic acid (DNA) and the production of interferon-gamma, more than doubled in attached lymphocytes in microgravity. The depression of the activation discovered in previous space experiments is due to an impairment not of the lymphocyte but of the macrophage function. The system described here may be useful for radiobiological investigations on the effect of high-energy particles and for testing the efficiency of the immune system in humans during the long-duration space flight planned in the future. The biotechnological significance of the increased lymphokine production in space remains to be assessed.     

Iodine intakes assessed by urinary iodine concentrations in healthy children aged ten months,two years,and four years

Urinary iodine excretion was assessed in 642 healthy children aged 10 mo (n=243), 2 yr (n=183), and 4 yr (n=216) living in the Paris area and originating from continental France (60.3%), North Africa (13.8%), the West Indies (9.1%), West Africa (8.3%), Southeast Asia (4.8%), and southern Europe (3.8%). Mild impairment of neurological (reflexes, tone, audiometry) and intellectual development (Brunet-Lézine scale) was assessed in relation to iodine status. Iodine excretions (median values) were 18.4, 11.9, and 10.9 μg/100 mL at 10 mo, 2 yr, and 4 yr, respectively, and risk of mild iodine deficiency (5–10 μg/100 mL) was 18.1%, 34.8%, and 38.3% for the same age groups. No relationship was found between anthropometry, global development quotient, and iodine status. High hearing thresholds were more commonly associated with lower iodine excretion, suggesting mild hearing defects. In spite of iodine prophylaxis, the risk of mild to moderate iodine deficiency still exists in France and in a number of European countries. Evaluation of neurological sequels of borderline iodine status is a major public health problem in European communities.     

Roles of iron in neoplasia

Research and clinical observations during the past six decades have shown that: 1. Iron promotes cancer cell growth; 2. Hosts attempt to withhold or withdraw iron from cancer cells; and 3. Iron is a factor in prevention and in therapy of neoplastic disease. Although normal and neoplastic cells have similar qualitative requirements for iron, the neoplastic cells have more flexibility in acquisition of the metal. Excessive iron levels in animals and humans are associated with enhanced neoplastic cell growth. In invaded hosts, cytokine-activated macrophages increase intracellular ferritin retention of the metal, scavenge iron in areas of tumor growth, and secrete reactive nitrogen intermediates to effect efflux of nonheme iron from tumor cells. Procedures associated with lowering host intake of excess iron can assist in prevention and in management of neoplastic disease. Chemical methods for prevention of iron assimilation by neoplastic cells are being developed in experimental and clinical protocols. The antineoplastic activity of a considerable variety of chemicals, as well as of radiation, is modulated by iron. The present article focuses on recent findings and suggests directions for further cancer-iron research.     

Bibionids (Diptera: Bibionidae) in agricultural land: a review of damage, benefits, natural enemies and control

Records of crop damage caused by Bibionidae are reviewed together with evidence for their beneficial activities, natural enemies and control methods. Bibionids are sporadic and infrequent pests. Although grass and cereals are most vulnerable, a wide range of crops is attacked. Damage is most severe after grass or when plants are under stress. The presence of organic matter during oviposition increases the likelihood of damaging populations. Many natural enemies exist but their impact on adult or larval populations has not been quantified. Given the pattern of attacks and lack of approved insecticides, cultural control methods are more appropriate than chemical. The role of adult bibionids in pollination and of larvae involved in soil processes could be of greater importance than any damage caused by the group.     

Pollenanalytical research in the Grisons (Switzerland)

In the first part, an overview of the history of palynological researeh in Switzerland and particularly in the Grisons is given, with a map showing all investigated areas in the Grisons. The second part deals with the significance of the pollenanalytical research in the Grisons, namely, the history of vegetation during the Late and Post Glacial, climatic fluctuations and applications in geomorphology, archaeology and forestry research. Finally, some results concerning the history of vegetation during the Late and Post Glacial are discussed.I would like to thank my colleague H. Holzhauser for his help with the drawing of the figures.