A new method for measuring guanidine in uremia

Riassunto Si descrive un metodo per la determinazione della guanidine nei liquidi biologici e si rileva che essa aumenta nel siero uremico fino a 30 volte la norma (valore medio normale: 1.41±0.49 g/100 ml) e che nei cani uremici la concentrazione muscolare è di quasi 3 volte superiore a quella plasmatica. La eliminazione urinaria non è diversa fra normali ed uremici: 382±221 e 459±229 g/24 h, rispettivamente.

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Aknowledgments. This investigation was supported by Public Health Service, Research Contract No. PH-43-68-1466.     

Selective gonadotrophin uptake by mouse ovarian carcinoma

Zusammenfassung Bei Mäusen mit Granulosa- oder Theca-Tumoren wurde die Bindung von¹²⁵I-HCG untersucht. Im Vergleich zur Bindung an andere Gewebe derselben Tiere konnte eine zellspezifische Bindung im Bereich der Tumoren festgestellt werden. Die Befunde werden im Zusammenhang mit der Zweizelltheorie der ovariellen Steroidgenese diskutiert.     

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 simple method for the study of the uptake of radioactive32P phosphate by red blood cells

Zusammenfassung Die P³²-Aufnahme in Erythrocyten wird durch Aktivitätsmessungen über Sediment und Überstand in einer Hämatokrit-Kapillare bestimmt.     

A new method for measuring membrane potentials with external electrodes

Zusammenfassung Beschreibung einer neuen Methode, die es gestattet, mit Aussenelektroden die wahre Grösse der Membranpotentialschwankungen, die durch den Einfluss von hyper- oder hypopolarisierenden Substanzen oder durch die Erregung in markhaltigen Nervenfasern erzeugt werden, zu registrieren.     

A method for measuring apatite crystals in human dentine by high resolution transmission electron microscopy]

High resolution electron microscopy now makes it possible to use an original method for measuring biological apatite crystals. The crystals of intertubular sound dentine have an average width of 296 A (standard deviation: 37) and an average thickness of 32 A (standard deviation: 5). During the course of so-called arrested caries, crystals get twice as thick compared to those sound dentine, whereas their width remains unchanged.     

A simple method for counting nuclei in the preimplantation mouse embryo

An easy and rapid method of counting the number of cells in the preimplantation mouse embryo is described. The procedure increases the speed with which large numbers of embryos can be processed using a simple squash technique. Cell numbers are determined by exposing the embryos to the fluorescent DNA-binding dye, Hoechst 33258, removing the zona pellucida and simply squashing the embryo and counting the number of fluorescent nuclei. An increase in fluorescent intensity and maintenance of nuclear conformation of the squashed preparations are greatly improved by the use of the non-ionic detergent Triton X-100. Viability of dye-treated fertilized one-cell and blastocyst stage embryos is maintained at least up to day 13 of pregnancy following transfer of the embryos to the uteri of pseudopregnant recipients. Additional uses for this staining technique are discussed.     

A simple method for counting nuclei in the preimplantation mouse embryo

Summary An easy and rapid method of counting the number of cells in the preimplantation mouse embryo is described. The procedure increases the speed with which large numbers of embryos can be processed using a simple squash technique. Cell numbers are determined by exposing the embryos to the fluorescent DNA-binding dye, Hoechst 33258, removing the zona pellucida and simply squashing the embryo and counting the number of fluorescent nuclei. An increase in fluorescent intensity and maintenance of nuclear conformation of the squashed preparations are greatly improved by the use of the non-ionic detergent Triton X-100. Viability of dye-treated fertilized one-cell and blastocyst stage embryos is maintained at least up to day 13 of pregnancy following transfer of the embryos to the uteri of pseudopregnant recipients. Additional uses for this staining technique are discussed.Acknowledgment. Financial support was provided by NIH Grant HDD-06210 (KME) and by Basil O'Connor Starter Research Grant No. 5-379 from the March of Dimes Birth Defects Foundation (VEP). We thank Steven Halpern for help with the photography and Jon Flax for expert technical assistance.     

A method of measuring the intensity of electron spin resonance absorption

Riassunto Si descrive un metodo che permette di misurare l'intensità di assorbimento ESR quando il campione standard e il campione su cui si esperimenta sono contemporamente presenti dentro la cavità risonante. Il campione standard viene situato in modo tale da rendere possibile l'eliminazione dell'assorbimento a cui esso da luogo, rotando il magnete attorno all'asse della cavità.     

A new,rapid and precise method for measuring the intra-cellular water content by gas chromatography and3H-sucrose

Summary A new rapid method for measuring intra-cellular water content by gas chromatography and an isotopic (³H-sucrose) technique is described. Water content of circulating red cells was revealed to be 71.26±0.31%. Intra-cellular water content increased to 102.9% of its original value following addition of 3 volumes of acid-citrate-dextrose (ACD) to 20 volumes of blood.     

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.     

Metaraminol uptake by human thrombocytes: A poor model for neuronal noradrenaline uptake

Summary The IC₅₀ of a number of antidepressants and related drugs on the uptake of 1-metaraminol and serotonin into human thrombocytes, and of noradrenaline and serotonin into rat midbrain synaptosomes were compared. In accordance with previous reports, it was found that platelets, provide a good model for the study of neuronal uptake of serotonin. Platelet uptake of 1-metaraminol, although correlated to some extent with noradrenaline uptake into synaptosomes, seems to be an unsatisfactory model for the neuronal uptake of the latter amine.     

A method for quantitative assessment of experimentally produced ulcers in the stomach of albino rats

Résumé Pour évaluer quantitativement les ulcères provoqués expérimentalement dans l'estomac des souris blanches, on dresse le tableau exprimant le rapport entre la muqueuse gastrique et la surface totale d'ulcération indice de l'ulcère. Il semble que la méthode décrite donne des résultats plus exacts car elle tient compte de l'étendue totale d'ulcération en fonction de la surface totale de l'estomac.