ACTH-induced hyperalgesia in rats.

The injection of ACTH 1--24 into the cerebral ventricles in rats markedly reduces the reaction time in the hot-plate test and the nociception threshold in the tail-stimulation test. Morphine antagonizes and naloxone potentiates this hyperalgesic effect of ACTH. It is proposed that ACTH peptides play a physiological role in nociception.     

Maxwell's role in turning the concept of model into the methodology of modeling

This is a contribution towards a history and philosophy of modeling in its early stages in electromagnetism. In 1873, James Clerk Maxwell (1831–1879) hinted at the methodology of modeling at the end of his Treatise on Electricity and Magnetism. We focus on Maxwell's impact on physicists who immediately followed him, specifically Oliver Lodge (1851–1940) and George Francis FitzGerald (1851–1901). We begin with the role that the scientific concept of model played in the late nineteenth century, as assessed by Ludwig Boltzmann (1844–1906). We then discuss the role of hypothesis as a methodology, the appeal to (dynamical) illustration, and the way Maxwell applied model and working model in his studies of electromagnetism. We show that for Maxwell these key terms were kept distinct, but Lodge did not maintain these distinctions and, in this regard, FitzGerald followed Lodge. Notwithstanding Lodge's influence, Fitzgerald modified Maxwell's theory based on the mechanical model he designed, thereby implicitly taking the first step towards modeling. This methodology consists in drawing consequences from the (mechanical) model to the (electrodynamic) theory and modifying the latter in light of the functioning of the former. At the core of our argument is the thesis that it was a methodological novelty to move from the concept of model to the methodology of modeling. The introduction of modeling as a new methodology into physics in the late nineteenth century was a major event which deserves proper recognition.     

Effect of ethidium bromide onDrosophila melanogaster andDrosophila simulans

Summary Ethidium bromide was fed toD. melanogaster andD. simulans males in order to test its toxic capacity and potency for the induction of dominant lethals. Our results show that ethidium bromide has a high toxicity and likewise produces dominant lethals to a significant extent in both species, but more effectively inD. melanogaster.     

A simple procedure for removal of intra- and extra-tumoral macrophages from primary tumor cultures

Summary Improved growth of tumor cells in primary cell suspensions isolated from solid tumors can be achieved by addition of an antifungal agent, mycostatin, to the culture medium. Mycostatin inhibits the cytotoxicity of macrophages and also quickly detaches phagocytes without any apparent retardation of the growth of tumor cells. This method is particularly useful for obtaining cultures of lung tumor cells or cells from lung metastases of other tumors.This research was supported in part by grants CA-22839 and CA-28482 awarded by the National Cancer Institute, DHEW, USA. This is publication No. 406 from the Department of Basic and Clinical Immunology and Microbiology, Medical University of South Carolina.We thank Charles L. Smith for editorial assistance. Address correspondence to Y. Y., Department of Basic and Clinical Immunology and Microbiology, Medical University of South Carolina, 171 Ashley Avenue, Charleston, SC 29403, USA.     

Release of renal kallikrein to the perfusate by isolated rat kidney

Summary The addition of furosemide to the fluid used to perfuse isolated rat kidney increases the kallikrein activity found in the perfusion fluid. The experiments favour the concept that furosemide activates a kallikrein precursor or/and the synthesis and release of kallikrein in the kidneys.     

Isolation of (−)-cryptosporiopsin,a chlorinated cyclopentenone fungitoxic metabolite fromPhialophora asteris f. sp.helianthi

Summary The (–)-enantiomer of cryptosporiopsin, a chlorinated cyclopentenone fungitoxic metabolite, was isolated fromPhialophora asteris f. sp.helianthi. Next to a comparable fungitoxic activity as shown by crypstosporiopsin, the product particularly inhibits growth ofSclerotinia sclerotiorum, an important pathogen on sunflower. Two further metabolites were tentatively identified as a stereoisomer of cryptosporiopsin and its dehydrated derivative.The authors are much indebted to Dr.G. M. Strunz (Canadian Forestry Service) for valuable suggestions and the generous gift of cryptosporiopsin and to the University of Utrecht for the part-time fellowship to one of us (Y.T.) given.     

Evaluation of participation of glucose in elevation of glycemia of scorpion (Heterometrus fulvipes) caused by the hyperglycemic principle of the scorpion and crab

Summary A single injection of the hyperglycemic principle obtained from scorpion cephalothoracic ganglionic mass causes an elevation of glycemia in the scorpionH. fulvipes in which little glucose is involved (10.8%). With the crustacean hyperglycemic principle, the elevation of glycemia is initially almost exclusively contributed by glucose (glucose is 92% of total carbohydrate at 2 h post injection); 6 h after treatment, non-glucose carbohydrates appear to participate in the elevation of glycemia.Acknowledgments. We wish to express our gratitude to CSIR, New Delhi for providing financial support to P.S.R., Reprint requests should be addressed to Prof. R. Ramamurthi.     

Comparison of cutaneous hyperemia in cattle elicited by larvae ofBoophilus microplus and by prostaglandins and other mediators

Summary Blood flow has been measured in bovine skin following the injection of tick antigens and a number of pharmacological mediators; including histamine, prostaglandins and slow reacting substance of anaphylaxis. The greates increase in blood flow (20 times normal) was recorded with tick antigens and with prostaglandin F2. This mediator may therefore influence blood flow during immune reactions to ticks and during the rapid ingestion of blood by the ticks.Acknowledgments. This work was supported by the Australian Meat Research Committee. We would like to thank J. M. Gough for her technical assistance.