Immunoglobulin synthesis by cord blood lymphocytes

Summary The IgG, IgA and IgM synthesis by adult peripheral blood and cord blood lymphocytes incubated alone and with pokeweed mitogen was quantitated. The cord blood lymphocytes produced no immunoglobulin even with mitogen stimulation while the adult peripheral blood lymphocytes responded to the mitogen with a significant (p<0.04) increase in immunoglobulin production.     

Microorganisms and ion absorption by roots

Résumé Les comparaisons des taux d'absorption de K par des racines d'orge stériles et non-stériles,Hordeum vulgare, dans l'ordre de concentration de 0,02–50 mM, ont montré que le double mode de transport d'ion décrit auparavant pour des racines non-stériles, s'applique également aux racines stériles. La microflore de la racine n'a influencé que légèrement les taux d'absorption de K.

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I thankD. L. Fredrickson for assistance with these experiments andF. E. Broadbent for advice. This research was supported by a grant from the Office of Saline Water, United States Department of the Interior.     

Carcinogenicity of tetraethyl lead

Zusammenfassung Ein vermehrtes Vorkommen von Lymphomas zeigte sich bei mit Tetraäthylblei behandelten weiblichen Mäusen (12%) im Gegensatz zu den entsprechenden Kontrollen (0%). Die carcinogene Wirkung von Tetraäthylblei wurde durch parenterale Administration einer totalen Dosis von 0.6 mg an neugeborenen Schweizer Mäusen gezeigt.

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Supported by Grant No. C-6516 from the National Cancer Institute, USPHS.     

Mapping and analysis of chromatin state dynamics in nine human cell types

Chromatin profiling has emerged as a powerful means of genome annotation and detection of regulatory activity. The approach is especially well suited to the characterization of non-coding portions of the genome, which critically contribute to cellular phenotypes yet remain largely uncharted. Here we map nine chromatin marks across nine cell types to systematically characterize regulatory elements, their cell-type specificities and their functional interactions. Focusing on cell-type-specific patterns of promoters and enhancers, we define multicell activity profiles for chromatin state, gene expression, regulatory motif enrichment and regulator expression. We use correlations between these profiles to link enhancers to putative target genes, and predict the cell-type-specific activators and repressors that modulate them. The resulting annotations and regulatory predictions have implications for the interpretation of genome-wide association studies. Top-scoring disease single nucleotide polymorphisms are frequently positioned within enhancer elements specifically active in relevant cell types, and in some cases affect a motif instance for a predicted regulator, thus suggesting a mechanism for the association. Our study presents a general framework for deciphering cis-regulatory connections and their roles in disease.     

Mitochondrial activity: A possible determinant of anoxic injury in renal medulla

Summary In brain¹, heart² and kidney³, cell work in the absence of oxygen has been thought to precipitate anoxic damage by increasing the rate of depletion of cellular energy stores. In the medullary thick ascending limb of isolated perfused rat kidneys, however, reduction of ATP synthesis by a variety of mitochondrial or metabolic inhibitors caused ATP depletion comparable to that produced by oxygen deprivation but did not reproduce the lesions of anoxia. In these cells, unrestrained mitochondrial activity may be an important source of anoxic injury.