The immunological network at the site of tumor rejection

The tumor mass irrespective of its type or location in the body has long been shrouded in mystery and even today we still have only a tentative handle on its secrets. Attempts to manipulate either the tumor cells per se or host-derived leukocytes have, on the whole, not been successful or at best questionable. The ability of the host to respond immunologically to TSTA is well documented, yet again attempts to manipulate this response have been disappointing. One of the problems has been a lack of knowledge concerning the tumor mass and its constituents, such as the intratumor leukocytes, and the significance of their presence to the biological properties of the neoplasm [8,9,80]. The purpose in studying the immunological network is, in part, to try to assign a function to these cells on the premise that lymphoid elements and macrophages have a potential role to play in recognition of TSTA. The advantage of adoptive immunotherapy model systems is that tumor rejection can be achieved under controlled conditions and this allows an analysis of the immunological network and its individual circuits. At the same time, valuable information on the mechanisms of action during adoptive immunotherapy and how best to improve therapeutic protocols is acquired.     

THE INDIRECT EFFECT OF PHOTOPERIOD ON TRACHEID DIAMETER IN PINUS RESINOSA

Larson , Philip R. (Lake States Forest Experiment Station, Rhinelander, Wis.) The indirect effect of photoperiod on tracheid diameter in Pinus resinosa. Amer. Jour. Bot. 49 (2) : 132–137. Illus. 1962.—The influence of photoperiod on tracheid diameter was studied by independently exposing the buds and needles to different photoperiods. Long days promoted needle elongation and large-diameter tracheid production, whereas short days brought about cessation of needle elongation and the transition to narrow-diameter tracheids. The response to photoperiod varied with the stage of plant development. During active extension growth of the shoot, the bud exerted a decisive regulatory influence on tracheid diameter, but the needles became the principal source of the stimulus contributing to tracheid diameter when extension growth terminated. It is suggested that the effect of photoperiod on tracheid diameter is indirect and associated with auxin production and distribution of the terminal meristems.     

Histochemical detection of horseradish peroxidase activity in the rat by the vibratome-paraplast method

A method is described for the histochemical detection of horseradish peroxidase in Paraplast Plus embedded brain sections. The procedure uses 150-micron-thick Vibratome-cut slices of glutaraldehyde-paraformaldehyde-fixed brain tissue. Tetramethylbenzidine stabilized by diaminobenzidine/cobalt/H2O2 is used as chromogen. The Vibratome-cut slices are dehydrated through a graded series of acetone, cleared in toluol and flat-embedded in Paraplast Plus embedding medium. Serial sections can be cut as thin as 5-7 micron. The method is universal in its application and permits optimal visualization of labeled neurons with great morphological detail at the light-microscopic level.