synthesis and biological testing of nonionic iodinated x-ray contrast media

A series of nonionic x-ray contrast media containing novel linkages between the triiodobenzene and polyhydroxy moieties have been prepared and screened against established criteria. Of the coupler groups examined (amide including dipeptide, carbamate, ureido, and ester), amide showed the greatest overall utility in terms of safety, solubility, stability, and ease of synthesis. Acute toxicity, solubility and stability data are summarized for each series. In the CNS, certain compounds were well tolerated and some were devoid of any excitatory effects. Intrathecal tissue irritant effects were also unremarkable. Most agents exhibited relatively high osmolalities, raising questions as to the influence of this factor on the safety of myelographic agents. Intravascularly, nonionic media appear also to offer advantages over classical ionic media. However, nonionic media can exert positive inotropic effects and exhibit high viscosity at higher iodine concentrations. Nevertheless, overall results continue to demonstrate the radiographic potential of nonionic contrast media.

Purification and characterization of winter flounder antifreeze peptide messenger ribonucleic acid

The serum of winter flounder contains a group of small antifreeze peptides which lower the freezing point of their body fluids during the winter months. The poly(A)-containing mRNA coding for these peptides has been isolated from livers of the winter specimens. When the isolated antifreeze mRNA was analyzed by a denaturing polyacrylamide gel electrophoresis, at least two distinct bands approximately 450 nucleotides in length are visible. In a wheat germ cell-free protein synthetic system these mRNAs direct the synthesis of small peptides which can be precipitated by antisera against purified winter flounder antifreeze peptides. Full-length cDNA was synthesized from the isolated antifreeze mRNA by avian myeloblastosis reverse transcriptase. From the RNA excess hybridization kinetic analysis, there are probably three different mRNAs coding for the antifreeze peptides. Using the radioactive cDNA probe, it was estimated that 1% of the total RNA in liver of a January specimen is antifreeze mRNA. RNA from a summar specimen showed no significant hybridization even at high concentrations of RNA. These results indicate that the control of antifreeze peptide biosynthesis relies at least in part on the synthesis or degradation of translatable mRNA.

Environmental regulation of gene expression. In vitro translation of winter flounder antifreeze messenger RNA

The serum of winter flounder contains a group of antifreeze peptides which lower the freezing point of their body fluid in the winter. These antifreeze peptides disappear from their serum in the summer when the water temperature rises. Messenger RNA isolated from the liver of flounder collected in January directs the synthesis of predominantly one protein in an in vitro protein synthesis system. This protein can be precipitated by the antiserum made from the purified antifreeze peptides and was identified as the precursor(s) of these peptides. There is a seasonal variation in the concentrations of mRNA coding for the antifreeze peptides in the liver which can be correlated with the appearance and disappearance of these peptides in the serum. However, the changes in the levels of mRNA occur much sooner than the changes in the levels of antifreeze peptides in the serum, suggesting that an additional control mechanism might have taken place at the translational level.

Antitubercular 2,8-bis(alkylaminomethyl)phenazines

The preparation and antitubercular properties of a series of 2,8-bis(alkylaminomethyl)phenazines are described. These compounds all inhibited the growth of Mycobacterium smegmatis ATCC 607 in vitro. 2,8-Bis(dibutylaminomethyl)phenazine (5c) was also active against a lethal Mycobacterium tuberculosis H37Rv infection in mice.

Bisamidines of 2,6-diaminoanthraquinone as antiamebic agents

A series of bisamidines of 2,6-diaminoanthraquinone was synthesized and tested against cecal and hepatic forms of Entamoeba histolytica infections in rats and hamsters, respectively. A number of compounds were found to have good activity against infections in both species.

Structure of a peptide antifreeze and mechanism of adsorption to ice

Sequence studies of an alpha-helical peptide antifreeze isolated from winter flounder have revealed the presence of clusters of polar amino acids separated by long sequences of alanine. Most of the polar residues are threonine and aspartate and are separated by 4.5 A, a repeat distance that also separates the oxygens in the ice lattice along the a-axis of an ice crystal. Such a lattice match suggests that the peptide binds to ice by means of hydrogen binding.

Effects of solid food on blood levels of alcohol in man

Forty-five ml of 95% alcohol, diluted to 150 ml with orange juice, was taken orally by six adult male volunteers under the following conditions: A (fasting), B (following a light breakfast), C (following a heavy breakfast), D (following a steak meal), E (alcohol 1 hr after a heavy breakfast), and F (alcohol 1 hr before a heavy breakfast). Using treatment A as a reference, the average area under the blood alcohol, time curve was reduced by 36, 63, 55, 56, and 18% for treatment B through F, respectively. The reduction in area is attributed to two factors: (a) food reduced the efficiency of absorption of alcohol; and (b) food reduced the rate of absorption of alcohol, which, coupled with the operation of Michaelis-Menten elimination kinetics, contributed to the reduction in area. The latter effect is a result of changes in the ratio: instantaneous rate of metabolism/amount of alcohol in the body, which results in a smaller area when the rate of absorption is slow than when the rate of absorption is rapid. Using treatment A as a reference, the ratio of the average peak alcohol concentrations were: 1.0, 0.72, 0.35, 0.50, 0.49 and 1.11 for treatments A through F, respectively.

Glycoprotein and protein antifreezes in two Alaskan fishes

Two macromolecular freezing point depressants have been isolated from the serums of two species of Alaskan fishes. A common property of the four antifreezes thus far isolated is a high alanine content which suggests that the mechanism of these antifreezes may be related to a repeating tripeptide unit.

Aglomerularism in Antarctic fish

Urine formation in antarctic bony fish does not involve glomerular filtration. Evidence for aglomerularism came from both direct observation of kidney serial sections by light microscopy and the low concentrations of inulin labeled with carbon-14 that were excreted into the urine when this renal clearance tracer was injected into the bloodstream via a cannula implanted in the caudal vein. Aglomerularism most likely prevents urinary loss of glycoproteins with biological antifreeze properties.

Sex similarity in personality correlates of test anxiety

Sex differences in correlation coefficients between the California Psychological Inventory, Sixteen Personality Factor Questionnaire scales and Alpert-Haber Achievement Anxiety Test scales were evaluated in four samples of Ss in French (54 males and 156 females), mathematics (124 males and 66 females), and two introductory psychology courses (81 males and 146 females in the first sample and 297 males and 349 females in the second sample). The fact that fewer than 7% of differences were significant at the 5% level in 216 pair-wise comparisons and there were significant correlations between correlation matrices seems to indicate the lack of sex differences in personality correlates of test anxiety.