Interleukin-4 increases cortisol release and decreases adrenal androgen release from bovine adrenal cells

ACTH is the primary regulator of adrenal function during acute stress. However, during chronic inflammatory stress additional factors play a major role in the regulation of adrenal secretion. Many cytokines circulate in the blood and are synthesized and released from adrenal tissue. Furthermore, these peptides modify adrenal function. Recently, interleukin-4 (IL-4) was demonstrated to be released from a human adrenal tumor cell line. Therefore, we hypothesized that normal bovine adrenocortical cells could express IL-4 and that this cytokine may modify adrenal function. We determined that IL-4 and IL-4 receptors (IL-4R) are expressed in the bovine adrenal cortex whereas the expression of IL-4 and IL-4R in the adrenal medulla was not apparent. Exposure of dispersed bovine adrenocortical cells isolated from the zona fasciculate to IL-4 did not modify basal release of cortisol. However, the ACTH-stimulated release of cortisol from the bovine adrenal cells was augmented by IL-4. IL-4 exposure had no affect on adrenal androgen release from bovine zona reticularis cells, but IL-4 inhibited the ACTH-stimulated release of adrenal androgens from these cells. The effects of IL-4 on ACTH-stimulated cortisol and adrenal androgen release were dependent upon the IL-4 incubation interval and the IL-4 concentration. Because communication between the immune and endocrine systems is important in inflammatory conditions, IL-4 may play a role in coordinating the adrenal response to inflammatory stress.     

Oxidative Stress in Neonatology. A Review

Free radicals are highly reactive oxidizing agents containing one or more unpaired electrons. Both in human and veterinary neonathology, it is generally accepted that oxidative stress functions as an important catalysator of neonatal disease. Soon after birth, many sudden physiological and environmental conditions make the newborn vulnerable for the negative effects of oxidative stress, which potentially can impair neonatal vitality. As a clinician, it is important to have in depth knowledge about factors affecting maternal/neonatal oxidative status and the cascades of events that enrol when the neonate is subjected to oxidative stress. This report aims at providing clinicians with an up‐to‐date review about oxidative stress in neonates across animal species. It will be emphasized which handlings and treatments that are applied during neonatal care or resuscitation can actually impose oxidative stress upon the neonate. Views and opinions about maternal and/or neonatal antioxydative therapy will be shared.     

Digestion of food samples for total mercury determination

A method of digestion by using a mixture of hydrochloric, nitric, and sulfuric acids has been developed for the determination of total mercury in a wide range of food samples. Good recoveries of mercury were obtained from NBS (National Bureau of Standards) Albacore Tuna and from food samples spiked with inorganic mercury. A detection limit of 0.01 microgram mercury/g can be obtained.     

Bacteria as Mediators of Copper Sulfide Enrichment During Weathering

Supergene chalcocite enrichment during weathering is an economically vital natural process that may lead to severalfold increases in the copper content of sulfide deposits. A scanning electron microscope study of chalcocite (Cu2S) from major enriched copper deposits in northern Chile revealed myriad bacterioform bodies in original growth positions near replacement interfaces with remnant hypogene sulfide grains. These minute (0.03 to 0.2 micrometers) chalcocite bodies are interpreted as fossilized and metallized nannobacteria that promoted the fixation of mobilized copper ions. Bacterial activity may thus be a fundamental factor in supergene enrichment of copper deposits.     

Scanning Single-Electron Transistor Microscopy: Imaging Individual Charges

A single-electron transistor scanning electrometer (SETSE)-a scanned probe microscope capable of mapping static electric fields and charges with 100-nanometer spatial resolution and a charge sensitivity of a small fraction of an electron-has been developed. The active sensing element of the SETSE, a single-electron transistor fabricated at the end of a sharp glass tip, is scanned in close proximity across the sample surface. Images of the surface electric fields of a GaAs/AlxGa1-xAs heterostructure sample show individual photo-ionized charge sites and fluctuations in the dopant and surface-charge distribution on a length scale of 100 nanometers. The SETSE has been used to image and measure depleted regions, local capacitance, band bending, and contact potentials at submicrometer length scales on the surface of this semiconductor sample.     

鉴别丁香假单胞菌丁香致病变种和豌豆致病变种的 DNA 探针的制备

把引起豌豆枯萎病的丁香假单胞菌丁香致病变种 Pseudomonas syringae pv.syringae 菌株3319和丁香假单胞菌豌豆致病变种 P.syringae pv.pisi 的模式菌株2452的染色体 DNA 分别用限制性核酸内切酶 HindⅢ完全消化,再用 T_4DNA 连接酶把消化好的 DNA 片段连接到用HindⅢ内切酶消化的质粒载体 pUC19上,然后把重组的质粒载体转化到大肠杆菌(E.coli RR1)中去克隆.把菌株3319和2452的 DNA 用 p~(32)标记做成探针,分别与克隆菌落杂交,筛选出只对菌株3319的 DNA 有特异性的1个重组 DNA 的克隆和对菌株2452的 DNA 有特异性的2个重组 DNA 克隆.再把这3个重组质粒 DNA 分别用 P~(32)标记做成探针,与菌株3319和2452的 DNA 杂交,也显示只对各自 DNA 来源的菌株具有特异性.这3个重组质粒中,有2个携带有菌株2452的 DNA 片段,1个为0.82 kb。另1个略小于0.58 kb,还有1个质粒携带有菌株3319的 DNA 片段,为0.85 kb.