Familial asymmetric crying facies. Its occurrence secondary to hypoplasia of the anguli oris depressor muscles.

Asymmetric crying facies is a common neonatal problem with multiple causes. Asymmetric crying facies occurred in a newborn, secondary to familial hypoplasia of the anguli oris depressor muscle. The differential diagnosis of asymmetric crying facies should include this genetic cause.     

Thermal inactivation of mouse brain monoamine oxidase type A and type B

Mouse brain monoamine oxidase (MAO) type A and type B were incubated at 54 degrees C and samples removed for up to 60 min, and remaining MAO activity was determined. Total MAO activity, type A activity and type B activity all disappeared, presumably due to thermal denaturation, in a time-dependent fashion. The rate of disappearance of MAO type B was faster than that of type A both at pH 7.4 and at pH 9.2, though both types denatured faster at the higher pH compared to the lower pH.     

Antitumor agents 68: effects of a series of helenalin derivatives on P-388 lymphocytic leukemia nucleic acid and protein synthesis

A series of analogues related to helenalin demonstrated moderate capability for inhibiting the growth of murine P-388 lymphocytic leukemia cells in vivo and in vitro. The growth inhibition correlated with suppression of both DNA and protein synthesis in P-388 cells. The inhibition of protein synthesis occurred at a relatively low concentration and appeared to occur at the level of initiation. The suppression of DNA synthesis in P-388 cells correlated positively with inhibition of inosine 5'-monophosphate dehydrogenase activity. Although nuclear and alpha DNA polymerase activities were suppressed by certain analogues, the inhibition of the polymerases did not correlate positively with DNA synthesis inhibition and, furthermore, the magnitude of suppression of DNA polymerase activity did not appear to be sufficient to account for the observed suppression of DNA synthesis in P-388 cells.     

Transcription in yeast: alpha-amanitin sensitivity and other properties which distinguish between RNA polymerases I and III.

Three peaks of DNA-dependent RNA polymerase (RNA nucleotidyltransferase) activity are resolved by chromatography of a sonicated yeast cell extract on DEAE-Sephadex. The enzymes, which are named RNA polymerases I, II, and III in order of elution, show similar catalytic properties to the vertebrate class I, class II, and class III RNA polymerases, respectively. Yeast RNA polymerase III is readily distinguished from yeast polymerase I by its biphasic amnonium sulfate activation profile with native DNA templates, greater enzymatic activity with poly[d(I-C)] than with native salmon sperm DNA, and distinctive chromatographic elution positions from DEAE-cellulose (0.12 M ammonium sulfate) compared with DEAE-Sephadex (0.32 M ammonium sulfate). The three yeast RNA polymerases also show significant differences in alpha-amanitin inhibition. RNA polymerase II is the most sensitive (50% inhibition at 1.0 mug of alpha-amanitin per ml). Contrary to the results for vertebrate systems, yeast polymerase I can be completely inhibited by alpha-amanitin at high concentrations (50% inhibition at 600 mug/ml) while yeast RNA polymerase II BEGINS TO SHOW SIGNIFICANT INHIBITION ONLY AT CONCENTRATIONS EXCEEDING 1 MG/ML. Therefore, yeast RNA polymerases I and III show a pattern of alpha-amanitin sensitivity that is the reverse of that seen for the analogous vertebrate RNA polymerases.