Sclerotherapy with tetracycline for hydrocele of the tunica vaginalis testis.
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Adolescent↗
Biomedical subjects
X Ding
Publications and source records attributed to X Ding.
Mössbauer studies on the metal-thiolate cluster formation in Fe(II)-metallothionein.
The stepwise 57Fe(II)-thiolate cluster formation in rabbit liver metallothionein-2 (MT) has been followed at pH 8.5 using Mössbauer spectroscopy. The zero-field spectra recorded at 4.2 K exhibit at all stages of filling one virtually identical single quadrupole splitting delta EQ and isomer shift delta as found for reduced rubredoxin (Rdred) or the model compound [Fe(II)(SPh)4]2-, thus indicating an Fe(II)-tetrathiolate coordination. A similar conclusion was reached also in previous electronic absorption studies [M. Good and M. Vasák (1986) Biochemistry 25,8353--8356]. The Mössbauer spectra obtained in the presence of a magnetic field were analyzed on the basis of a spin-Hamiltonian formalism resulting in Mössbauer parameters similar to those for Rdred and the inorganic model compound [Fe(II)(SPh)4]2-. The identity of the Mössbauer parameters of partially and fully metal-occupied MT suggests that a comparable distortion of the metal binding sites must exist. Simulation of the spectra revealed that the Fe(II) ions in the partially metal-occupied 57Fe(II)4-MT form appear to be magnetically isolated, whereas in the fully metal-saturated 57Fe(II)7-MT form a ratio of 3:4 of paramagnetic to diamagnetic subspectra was obtained. The latter result suggests the existence of three isolated metal binding sites and a metal-thiolate cluster containing four metal ions. In the light of structure determinations of MT containing Zn(II) and/or Cd(II) [W. Braun et al. (1986) J. Mol. Biol. 187, 125-129, and W. F. Furrey et al. (1986) Science (Wash. DC) 231, 704-710], which revealed two metal-thiolate clusters containing three and four metal ions, respectively, and involving all 20 cysteine residues in metal binding, the appearance of Mössbauer parameters characteristic of three isolated Fe(II) sites in 57Fe(II)7-MT is peculiar and deserves further studies. It is concluded, moreover, that the four-metal cluster is diamagnetic with the four Fe(II) ions being antiferromagnetically coupled. The appearance of magnetic coupling above four Fe(II) equivalents bound to apoMT indicates that the cluster formation occurs in a two-step process.
Animals↗
Improvement of spiral MRI with the measured k-space trajectory.
The k-space trajectory of a spiral imaging sequence was measured with a self-encoding technique. The image quality improved dramatically when reconstructed with the measured k-space trajectory. There were substantial artifacts in images reconstructed with the derived k-space trajectory under the assumption of gradient system linearity. The results indicated the non-linearity of the gradient system and the effectiveness of the correction technique.
Analog-Digital Conversion↗
Induction of P-450 cytochromes 2E2, 1A1, and 1A2 by imidazole in neonatal rabbits.
Cytochrome P-450 2E1 is induced in adult rabbits by treatment with alcohol, imidazole, and a variety of other agents, as shown earlier in this laboratory, but it is not known whether the highly homologous P-450 2E2 is similarly induced. In this study, the effects of imidazole on 2E2 expression were examined in neonatal rabbits, in which 2E1 is not detectable. Treatment of the animals with imidazole on days 8 through 11 after birth caused a 3-fold increase in the content of total P-450 in liver microsomes. In contrast, the microsomal content of cytochrome b5 and NADPH-P450 reductase was not changed. Immunoblot analysis revealed a significant increase in the level of P-450 2E2 (3-fold) as well as 1A1 (> 10-fold) and 1A2 (> 2-fold) in hepatic microsomes from imidazole-treated neonatal rabbits. The rates of microsomal N-demethylation of N-nitrosodimethylamine and O-deethylation of 7-ethoxyresorufin were similarly increased from 1.3 and 0.03 nmol/min/mg protein, respectively, to 5.6 and 0.24 nmol/min/mg protein, respectively, by imidazole treatment. Blot analysis indicated that the levels of 2E2, 1A1, and 1A2 mRNAs are not increased by imidazole treatment and that 2E1 mRNA is not detectable in either untreated or imidazole-treated neonates. The induction of P-450 2E2 was confirmed by NH2-terminal amino acid sequence analysis of immunopurified 2E protein from hepatic microsomes of imidazole-treated neonatal rabbits.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗