Specific radioimmunoprecipitation of histone H2A antigens by protein A conjugated sepharose

Summary A modified radioimmunoprecipitation technique is described which allows the specific detection of histone H2A antigens. The technique circumvents unspecific binding of histones to the bacterial adsorbent.     

Vitamin A and tumor immunity

Summary Intraperitoneal administration of vitamin A into the BALB/c mice inoculated with a syngeneic fibrosarcoma, Meth A, caused a remarkable augmentation of tumor rejection. A cell-depletion technique revealed that the primary effector cells responsible for the augmented rejection were Thy-1 positive, Lyt-1 negative, Lyt-2 positive lymphocytes, suggesting the involvement of cytotoxic lymphocytes.This work was supported in part by a Grant-in-Aid for scientific research from the Ministry of Education, Science and Culture, Japan, and in part by a Grant-in-Aid for cancer research from the Fukuoka Cancer Society, Japan.We thank Mr M. Fujiki and Miss A. Maeda for excellent technical assistance.     

A new technique of pinealectomy for adult rats

Summary A new technique of pinealectomy for rats is described which brings the pineal into view of the experimenter facilitating its removal and also allows for completely parallel sham operations.Acknowledgments. We thank Drs J. A. Mitchell, R. R. Gala and A. Weinsieder for their cooperation in the initial phases of this work and Hedwig A. Murphy for her help with the illustrations. Supported by USPHS, grant No. RR 05384, and the Department of Anatomy.     

A simple one-step procedure for staining the nucleolus organizer regions.

A simple silver staining technique for routine use is described by which the nucleolus organizer regions of mammalian chromosomes, including those of mouse chromosomes, are stained selectively.     

A simple technique for gastric parietal cell vagotomy in the rat

Summary A rapid and simple technique of parietal cell vagotomy in the rat caused a marked inhibition of basal and stimulated gastric secretion with minimal effect on gastric emptying and gastric volume.     

A simplified method for isocratic HPLC analysis of polyamines

A simple technique is described for the separation and analysis of polyamines in tissues and body fluids, utilizing precolumn clean-up on disposable CM-cellulose columns, followed by an automatable HPLC procedure. Complete separation and analysis takes 12-15 min per sample with sensitivity in the pmole range.     

A successive filtering technique for identifying long-term trends

The most reliable component of a time series, for forecasting purposes, is the shape of the long-term trend. However, the presence of cycles makes it difficult to identify and predict the changes in such trends. While up to now emphasis has been given in identifying and measuring cyclical behaviour, this paper presents a technique that aims at removing cyclical effects from the long-term trends. This technique is based on a transformation that is successively applied on the original time series. Each time the transformation is applied, an observation is selected and replaced by the average of its adjacent observations. This results in the elimination of the cyclical component. Independently of their depth, the cycles are being removed in ascending order relatively to their length. This leads to 'brushing off' the long-term trends from any cyclical effects. A specialized software has been developed in Pascal. The proposed technique was applied in a set of time series from the M2- and M-competition and the results are presented in this paper.     

A cell-marking technique for a cellular slime-mold

Summary A simple technique for marking cells of the cellular slime moldDictyostelium discoideum has been developed, using the phagocytic action of the cells. TheD. discoideum are fed onE. coli stained with neutral red and clearly red colored amoebae are obtained.     

A simple one-step procedure for staining the nucleolus organizer regions

Summary A simple silver staining technique for routine use is described by which the nucleolus organizer regions of mammalian chromosomes, including those of mouse chromosomes, are stained selectively.Acknowledgment. We would like to thank Prof. Dr K. Sperling for critical and helpful discussion.     

A rapid electrophoretic method for the separation of hydroxyproline from proline

Summary A rapid, sensitive procedure is described which uses custom made apparatus to separate radioactive imino acids. This technique provides a simple measurement of the distribution of newly synthesized collagen in different fractions.Acknowledgment. This work was supported by grants from the International Wool Secretariat.     

A new method for measuring radioactivity in select areas of intact tissue sections.

A new technique is described for measuring radioactivity in select areas of intact tissue sections. The method, which makes use of a liquid scintillation counter, also makes possible identification of the studied zones by prestaining.     

A simple technique for the measurement of 3H- and 14C-radioactivity per microgram DNA in fixed tissue

A simple, rapid and versatile technique for scintillation counting of double labelled fixed tissue is described. Furthermore, DNA determination can be performed on the same tissue digest.     

A simple technique for the measurement of3H- and14C-radioactivity per μg DNA in fixed tissue

Summary A simple, rapid and versatile technique for scintillation counting of double labelled fixed tissue is described. Furthermore, DNA determination can be performed on the same tissue digest.The financial support of the Norwegian Research Council for Science and the Humanities and the skillful technical assistance of Mr A. Vonheim are gratefully acknowledged.     

A rapid method for measuring the phospholipid synthetic activity of incubated lymphocytes

Summary A rapid and simple method for estimating the phospholipid synthetic activity of incubated lymphocytes by a Florisil column technique following the uptake of¹⁴C-oleic acid was established. Stimulation of phospholipid synthesis by PHA and inhibitions caused by Tween 20 or Tween 80 and heating were evaluated easily with this method.     

A simplified method for isocratic HPLC analysis of polyamines

Summary A simple technique is described for the separation and analysis of polyamines in tissues and body fluids, utilizing precolumn clean-up on disposable CM-cellulose columns, followed by an automatable HPLC procedure. Complete separation and analysis takes 12–15 min per sample with sensitivity in the pmole range.Acknowledgments. Supported by USPHS HD-09713, EPA R811621010 and by Research Scientist Development Award DA-00006 to TAS.     

A simple method for obtaining high plating efficiencies with cultured insect cells

Summary A technique has been developed for obtaining absolute plating efficiencies as high as 79% for culturedTrichoplusia ni (TN-368) cells. The method involves the use of conditioned medium and MES, BES, or ACES buffers. Cell growth and morphology are not altered under these conditions.     

A simple technique for scintillation counting of cell preparations on coverslips

Summary A simple, rapid and versatile technique for scintillation counting of cells on coverslips is described. The cells are conserved for subsequent staining and autoradiography so that other data can be collected from the same specimen.The financial support of the North West Cancer Research Fund (U.K.) and the skilled photographic assistance of Mr I. Miller are gratefully acknowledged.     

A new method for measuring radioactivity in select areas of intact tissue sections

Summary A new technique is described for measuring radioactivity in select areas of intact tissue sections. The method, which makes use of a liquid scintillation counter, also makes possible identification of the studied zones by prestaining.The financial support of the Israel Cancer Association is gratefully acknowledged.Acknowledgment. We sish to thank Professor H. Nathan for his help and support and Professor J. Lenge for his constructive reading of the article.     

A simple method of cannulating the portal vein and obtaining multiple blood samples in the rat

Summary A simple and rapid technique for cannulating the portal vein in the rat is described. Multiple blood samples can be obtained or alternatively substrate may be infused through the cannula.Supported by the Clayton Foundation for Research, Houston, Texas. Common resource support was also provided by the Research Service of the Veterans Administration. To whom reprint requests should be addressed as follows.     

Perifused alveolar macrophages. A technique to study the effects of toxicants on prostaglandin release

Summary A technique was developed for perfusing free airway cells (FAC) obtained by guinea-pig bronchoalveolar lavage. 10×10⁶ FAC (mostly macrophages) were placed on the filter of a Nuclepore chamber perfused with Tyrode's solution or with Eagle's Minimal Essential Medium (MEM); the effluent was collected at intervals and the release of prostaglandin E₂ by the perifused cells was used as an index of the inflammatory reaction to toxicants. Zymosan, asbestos fibers and soluble toxic agents stimulated the synthesis of prostaglandins while indomethacin abolished it. Our technique of FAC perifusion allows the sequential study of biochemical events involved in macrophage defense mechanisms as well as providing a simple test for the evaluation of various toxicants.Acknowledgments. The authors thank the Conseil de la Recherche en Santé du Québec and the Centre de recherches médicales de l'Université de Sherbrooke for their generous support, and Miss Solange Cloutier for skilful technical assistance.