A simple method for blood exchange in mice

Summary Ease of transfusion and high long-term survival rate were obtained when whole blood was administered via the corpus cavernosum of the penis and removed from the orbital sinus of male C57Bl mice. When 2 volumes of blood are replaced approximately 14% of pre-transfusion red cells remain after hematocrit corrections are made. The posttransfusion hematocrit levels dropped 19%, probably the result of leakage, which is difficult to avoid.Supported in part by NIH Grant No. CA08318 and NIH Center Grant No. CA14520.I acknowledge with thanks the technical assistance of Mrs.Joan Mitchen and Ms.Irene Uebersetzig. I am grateful to Mr.Randy Jirtle for providing the labelled red cells and for his interest in these studies.     

A simple method for heme isolation

Zusammenfassung Neues Verfahren für Häm-Isolierung durch Aceton-Fällung: Lösung in Aethylacetat-Eisessig und Auskristallisieren mit Wasserzugabe.     

A simple method for reconstructing serial sections

Résumé On décrit une méthode simple de reconstruction des sections sériées qui évite l'exécution fastidieuse d'un grand nombre de dessins. Bien qu'elle ne donne pas une image à trois dimensions, cette méthode est aussi utile qu'une autre pour étudier l'anatomie et les relations structurales par reconstruction de sections sériées.     

A cytological method for sexing young chicks

Zusammenfassung Beschreibung einer cytologischen Methode zur Bestimmung des Geschlechts junger Küken auf der Basis von gepaarten oder ungepaarten Geschlechtschromosomen.     

A simple method for reduction of non-specific fluorescence

Résumé Cette technique pour la réduction de la fluorescence non-spécifique utilise diverses méthodes communes en une série spéciale. Premièrement, les anticorps fluorescents sont adsorbés avec la poudre du foie. Suivant la centrifugation, une colonne de Séphadex-25 est utilisée pour séparer la fluorescéine libre. La méthode contraire donne une fluorescence non-spécifique qui ressemble à celle obtenue avec une seule adsorption ou Séphadex filtration.     

A simple enzymatic method for isolation of hepatocytes

Summary A new method is described for isolating hepatocytes by an enzymatic procedure: 0.05% bacterial collagenase in calcium-free Hanks' solution is injected into the liver tissue which is removed aseptically. The time required to prepare culture and risk of bacterial and fungal contamination is greatly reduced.     

A simple method for the preparation of diastereoisomeric phosphonodipeptides

Summary Diastereoisomeric mixtures of phosphonodipeptides, prepared from racemic dialkyl 1-aminoalkanephosphonates, were separated by ion-exchange column chromatography.     

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 cultivating the early chick embryo in vitro

Summary A method for cultivating the early chick embryo in an artificial medium has been developed that permits the determination of the stage at the onset of the treatment and the continuous observation of the embryogenesis.Kungliga Fysiografiska Sällskapet, Lund, supported this work.     

Intrasplenic infusion. A simple method for intraportal infusion in rats

Summary A simple and time-saving method for intraportal acute or chronic infusion in the rat by the insertion of a catheter into the spleen is described. This method has proved to be especially useful for performing chronic infusions in conscious animals.The author thanks Providencia Cruz for excellent secretarial assistance. Present address: Veterans Administration Center, Medical Research Division, San Juan, Puerto Rico.     

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 simple method for estimating melanophore responses to drugs in fishes

Résumé On décrit une technique simple pour mesurer les réactions mélanophoriques dans la peau des poissons.     

A method for osseal radiomicrometric measurements in mice experiments

Zusammenfassung Verbesserte röntgenologische Mess-methode zur Bestimmung von Knochenatrophien bei unmittelbar nach der Geburt thymektomierten, vom «wasting»-Syndrom befallenen Mäusen.