Extreme central acidosis from Abbott epinephrine

Investigation into the cause of extreme systemic acidosis during cardiac arrest led to the discovery that a major contributing factor was Abbott 1:10,000 single-dose epinephrine, which contained a large unsuspected acid level. Analysis of this product, both in vivo and in vitro, demonstrated that it contained 8.2 times the acid content of a presumably identical product from Bristol Laboratories and also of a presumably identical product from Bristol Laboratories and also 1,850 times the acid content of an identical epinephrine dose made from a Parke-Davis preparation. Abbott epinephrine injected into the central circulation or directly into the heart causes extreme acidemia, which may be potentially lethal by itself when superimposed on pre-existing acidosis as in cardiac arrest.

Heat-shock proteins in sea urchin embryos. Transcriptional and posttranscriptional regulation

The production of heat-shock proteins in sea urchin embryos is accompanied by the appearance at the polysomal level of their relative mRNAs, as shown by their translation in a cell-free system; thus suggesting that the regulation of their production occurs at a transcriptional level. The mechanism for the inhibition of the bulk protein synthesis and for its reversal on the other hand should be looked for at a posttranscriptional level, since both these phenomena occur also in the presence of actinomycin D. The heat-shock proteins produced as early as at the mesenchyme blastula stage persist within the embryo at least till the pluteus stage.

Defects in DNA and globin messenger RNA in homozygotes for hemoglobin Lepore

Globin messenger RNA (mRNA) isolated from three patients homozygous for hemoglobin Lepore is shown to have a marked reduction of the amount of beta-like globin mRNA (Lepore-globin mRNA sequences) compared with alpha-globin mRNA by molecular hybridization. The relative amounts of alpha- and Lepore mRNA are similar to the amounts of alpha- and Lepore globin synthesized in intact cells and by isolated mRNA in a cell-free system. It is also demonstrated that Lepore-globin mRNA can completely hybridize to full-length or nearly full-length beta-globin specific complementary DNA and protect it from nuclease digestion, indicating close homology between the delta-mRNA sequences present in Lepore mRNA and the beta-complementary-DNA probe. We have also quantitated the numbers of beta-like globin gene sequences in genomic Lepore DNA by molecular hybridization and demonstrated a reduction in their number consistent with the Lepore gene being a delta beta-gene fusion product.

Abnormal or absent beta mRNA in betao Ferrara and gene deletion in delta beta thalassaemia

In patients with betao thalassaemia from Ferrara, beta globin mRNA sequences are either absent or structurally abnormal while in betao thalassaemia in Catania, beta globin mRNA sequences are present. In deltabeta thalassaemia there is a deletion of beta-like globin genes, while in betao Catania DNA, no beta globin gene deletion is detectable.

Changes in globin messenger RNA content during erythroid cell differentiation

Previous studies have shown that mouse fetal erythroid precursor cells isolated by an immunological technique synthesize little or no globin and contain little, if any, globin mRNA, as assayed in a cell-free system (translatable mRNA). After culture for 10 hours in the presence of erythropoietin, there is a marked increase in globin synthesis and in translatable globin mRNA. The present studies were designed to measure directly the content of globin mRNA sequences during erythroid cell differentiation, by molecular hybridization with 3H-labeled DNA complementary to globin mRNA. The results indicate that few, if any, globin mRNA sequences are present in the total RNA of erythroid precursor cells. There is little or no pool of untranslated globin mRNA in these cells. After 10 hours of culture with erythropoietin, there is an increase in globin mRNA content, as ;easured by a change in the Cot1/2 values obtained by cDNA: mRNA hybridization with (Co) representing the concentration of RNA. Between 0 and 22 hours of culture, there is a 250-fold rise, and between 22 and 44 hours, a further 2-fold increase in globin mRNA content. During the 44 hours in culture, the number of cells in culture increases 2- to 3-fold. The number of globin mRNA molecules rises in erythroid precursor cells to an average value of 1800 molecules/cell during 22 hours of culture. In cultures without added erythropoietin, the absolute number of cells decreases, however, cells presumably induced to differentiate by exposure to erythropoietin in vivo continue to differentiate in vitro, accumulating globin mRNA and initiating globin synthesis.

Diagnosis of acute myocardial infarction. Relative efficiency of serum enzyme and isoenzyme measurements

Total serum enzyme activity for creatine phosphokinase (CPK), alpha-hydroxybutyric dehydrogenase (HBDH), lactic dehydrogenase (LDH), and serum glutamic oxaloacetic transaminase (SGOT), as well as the isoenzymes of CPK and LDH, were measured on admission and for ten subsequent days in 100 patients admitted consecutively to a coronary care unit. On discharge, patients were classified by a cardiologist as either having or not having suffered an acute myocardial infarction (MI) on the basis of clinical and electrocardiographic criteria--without knowledge of the enzyme studies. The combined use of CPK and LDH isoenzyme levels provided the greatest laboratory discrimination between the two clinical groups (MI vs non-MI). The routine use of HBDH and SGOT levels can be abandoned in the setting of a coronary care unit if CPK and LDH isoenzyme assays are available.

A limited number of globin genes in human DNA

The number of globin genes in human cells was determined by hybridizing DNA from human spleens to (3)H-labeled DNA complementary to human globin mRNA. Assuming the rates of reannealing of complementary DNA and cellular DNA are similar, the extent of hybridization of complementary DNA at various ratios of cellular DNA to complementary DNA indicate that there are fewer than 10 globin gene copies per haploid human genome. An alternative analysis of the data, which introduces no assumptions concerning the relative rates of reaction of complementary DNA and cellular DNA, indicates fewer than 20 globin gene copies are present. DNA isolated from the spleen of a patient with beta(+) thalassemia contained a number of globin gene copies similar to that of normal DNA.

Nucleotide sequence analysis of RNA synthesized from rabbit globin complementary DNA

Rabbit globin complementary DNA made with RNA-dependent DNA polymerase (reverse transcriptase) was used as template for in vitro synthesis of (32)P-labeled RNA. The sequences of the nucleotides in most of the fragments resulting from combined ribonuclease T(1) and alkaline phosphatase digestion have been determined. Several fragments were long enough to fit uniquely with the alpha or beta globin amino-acid sequences. These data demonstrate that the cDNA was copied from globin mRNA and contained no detectable contaminants.

Decreased globin messenger RNA in thalassemia detected by molecular hybridization

In previous studies of patients with beta thalassemia, mRNA extracted from reticulocytes in peripheral blood when added to cell-free systems reproduces the deficient beta-chain synthesis characteristic of intact cells. The present studies with specific probes for alpha and beta mRNA were designed to decide whether the decreased beta mRNA activity is due to the presence of abnormal or reduced beta globin mRNA in these cells. Purified alpha and beta complementary DNAs (cDNAs) have been synthesized with RNA-instructed DNA polymerase; alpha and beta mRNAs isolated from heavy (beta-producing) and light (alpha-producing) polyribosomes of rabbit reticulocytes were used as templates. Each of the cDNAs is more than 80% pure by the criterion of biological activity. The alpha cDNA labeled with [(32)P]dCTP and the beta cDNA labeled with [(3)H]dCTP have been added simultaneously to reaction mixtures containing various concentrations of mRNA from thalassemic and nonthalassemic subjects. The extent and rate of hybridization were determined, permitting a comparison of relative alpha and beta mRNA content in the same annealing mixture. In six nonthalassemic patients, relatively equal amounts of hybridizable alpha and beta mRNA appear to be present. In five of seven patients with beta-thalassemia, significantly decreased amounts of beta mRNA compared to alpha mRNA can be demonstrated. In two patients with Hemoglobin H disease, there is a decreased amount of alpha mRNA compared to beta mRNA.

The mechanism of protein synthesis activation after fertilization of sea urchin eggs

Upon fertilization of Paracentrotus lividus eggs, the ability of their ribosomes to form a ternary complex with poly(U) and phenylalanyl-tRNA is enhanced. In addition, it is possible to extract from ribosomes of the unfertilized egg a protein factor that inhibits polyphenylalanine synthesis by decreasing the binding of mRNA and aminoacyl-tRNA to the ribosomes. The observed increase in the rate of protein synthesis that occurs at fertilization could be accounted for by the removal of this inhibitory protein from the ribosomes.