A white girl presented at age 16 yr with delayed puberty and primary amenorrhea. She had 46 chromosomes with a de novo reciprocal X;9 translocation. The normal X chromosome was found to be heterochromatic, thus preserving the function of the translocation portion of the 9. Her total estrogen and serum estradiol levels were low and her serum follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels were at the lower end of the normal adult range. She had a reasonably good FSH and LH response to GnRH, but an inadequate response to 100 mg of clomiphene daily for 1 wk. This would suggest that the abnormality of function is probably hypothalamic, a hitherto unreported association. De novo translocations between X chromosomes and autosomes are rare and none identical to this case has been described. The breakpoint of the X chromosome was at p22, well outside the "critical region" for female reproductive function. It seems probable that her chromosome abnormality is responsible for her clinical state.
Formaldehyde treatment of Escherichia coli curves, and polarization of fluorescence thermal profiles B transfer ribonucleic acid (tRNA) appreciably changes indicate that (1) Watson-Crick hydrogen bonding hydrodynamic and optical properties. The increase is a determinant in the configuration and helix-coil in intrinsic viscosity, decrease in sedimentation coeffi-transition of native E. coli tRNA and (2) base stacking cient coupled with the change in absorbance melting contributes to the helical rigidity in native tRNA.
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