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31.
WFC Van Gelderen M Al-Hindawi CG Archibald AEH Merrie KS Cheng 《Journal of Medical Imaging and Radiation Oncology》1995,39(4):408-410
A dermold cyst, arising from the posterior aspects of the prostate and seminal vesicles, and extending into the pelvis to masquerade as a full bladder, must be exceedingly rare. Ultrasound, computed tomography and especially magnetic resonance imaging (MRI) proved to be invaluable in making the diagnosis, and MRI in particular was very useful in providing an anatomical road map for surgery. 相似文献
32.
Porter DW; Yakushiji H; Nakabeppu Y; Sekiguchi M; Fivash MJ Jr; Kasprzak KS 《Carcinogenesis》1997,18(9):1785-1791
The toxicity of Ni(II), Co(II) and Cu(II) in animals, and that of Cd(II) in
cultured cells, has been associated with generation of the promutagenic
lesion 8-oxo-7,8-dihydroguanine (8-oxoguanine) in DNA, among other effects.
One possible source of this base may be 8-oxo-7,8-
dihydro-2'-deoxyguanosine-5'-triphosphate (8-oxo-dGTP), a product of
oxidative damage to the nucleotide pool, from which it is incorporated into
DNA. To promote such incorporation, the metals would have to inhibit
specific cellular 8-oxo-dGTPases that eliminate 8-oxo-dGTP from the
nucleotide pool. The present study was designed to test such inhibition in
vitro on 8-oxo-dGTPases from two different species, the human MTH1 protein
and Escherichia coli MutT protein. In the presence of Mg(II), the natural
activator of 8-oxo-dGTPases, all four metals were found to inhibit both
enzymes. For MTH1, the IC50 values (+/- SE; n = 3-4) were 17 +/- 2 microM
for Cu(II), 30 +/- 8 microM for Cd(II), 376 +/- 71 microM for Co(II) and
801 +/- 97 microM for Ni(II). For MutT, they were 60 +/- 6 microM for
Cd(II), 102 +/- 8 microM for Cu(II), 1461 +/- 96 microM for Ni(II) and 8788
+/- 1003 microM for Co(II). Thus, Cu(II) and Cd(II) emerged as much
stronger inhibitors than Ni(II) and Co(II), and MTH1 appeared to be
generally more sensitive to metal inhibition than MutT. Interestingly, in
the absence of Mg(II), the activity of the enzymes could be restored by
Co(II) to 73% of that with Mg(II) alone for MutT, and 34% for MTH1, the
other metals being much less or non-effective. The difference in
sensitivity to metal inhibition between the two enzymes may reflect the
differences in the amino acid ligands, especially the cysteine ligand,
outside their evolutionarily conserved Mg(II)-binding active sites, which
might indicate predominantly non-competitive or uncompetitive mechanism of
the inhibition. The overall results suggest that inhibition of 8-oxo-
dGTPases may be involved in the mechanisms of induction of the 8-
oxoguanine lesion in DNA by the metal ions studied, especially the non-
redox-active Cd(II) cation.
相似文献
33.
Mucormycosis is a rare fungal infection of childhood, occurring mainly in
patients with chronic illnesses such as diabetes and malignancies. The
fungus seldom grows in culture and confirmation of the diagnosis depends on
histologic examination of infected tissues. To date, the reported natural
history of the disease has been rapid progression and a fatal outcome.
Therefore, the importance of early diagnosis by tissue biopsy and early
treatment with surgical debridement and systemic antifungal therapy cannot
be overemphasized. The pulmonary system is the most common site for
mucormycosis in patients with leukemia. We report what we believe to be the
first successfully treated case of isolated muscular mucormycosis occurring
in a child with biphenotypic acute leukemia. The diagnosis was made
promptly by tissue examination at the time of surgical debridement. The
patient was also given systemic amphotericin-B therapy.
相似文献
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The role of divalent cations in platelet adherence to deendothelialized human arteries in flowing blood was investigated in an annular perfusion chamber. Spreading of platelets on the subendothelium was impaired below 30 microM of free Ca2+ ions (Ca2+). When Ca2+ was replaced by Mg2+, adherence was unchanged in perfusates without exogenous factor VIII-von Willebrand factor (FVIII-vWF), but the ability of FVIII-vWF to support platelet adherence was lost. Binding of FVIII-vWF to the vessel wall was independent of divalent cations, but bound FVIII-vWF was only able to mediate adherence after exposure to Ca2+. Pretreatment of FVIII-vWF with the calcium chelator EGTA (10 mM) resulted in loss of the ability to facilitate platelet adherence, while the ristocetin cofactor activity remained intact. Full restoration of the ability to mediate platelet adherence could only be obtained by prolonged dialysis against Ca2+ in the millimolar range. These data indicate that divalent cations have at least two separate roles to play in supporting platelet adherence: (1) platelet spreading on the subendothelium requires Ca2+ or Mg2+; (2) FVIII-vWF should be exposed to Ca2+ to obtain its optimal biologic activity in supporting platelet adherence. 相似文献
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