Current concepts about multiple sclerosis.
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Humans↗
Biomedical subjects
P W Pick
Publications and source records attributed to P W Pick.
Occurrence of breast carcinoma within a fibroadenoma. A review.
Sixty-two cases of carcinoma within a breast fibroadenoma are adequately documented in the literature, including the present case. All are found in women. The mean age of occurrence is 42.4 years. This corresponds to the peak age of lobular in situ breast cancer but is much higher than the peak age for breast fibroadenomas. Sixty-five percent of patients harboring cancer within a fibroadenoma have lobular in situ malignant neoplasms. In 42% of the cases the surrounding breast tissue is also involved by cancer, a fact that dictates generous surgical margination of all fibroadenomas excised, especially in older women. The data indicate that the presence of the fibroadenoma is a parameter independent of the development of cancer in either the ipsilateral or contralateral breast and does not influence the clinical course of the malignant neoplasm, other than that it contributes to its earlier detection. Treatment should follow the general principles of therapy for the in situ or infiltrative breast cancers.
Adenofibroma↗
Protein thiol-disulfide interchange and interfacing with biological systems.
Disulfide-containing proteins offer unique advantages for mechanistic studies of the formation of native three-dimensional structure from unordered, reduced precursors. The main advantage is that covalent intermediates are formed; by characterizing these intermediates, one obtains substantial information about the reaction pathway. Thiol-disulfide interchange is a major component of most oxidative mechanisms carrying thiol to disulfide; thus, it required some attention in its own right. Afinsen's descriptions of a "shuffle-ase" enzyme led us to examine the rates of the uncatalyzed exchange under physiologically plausible conditions. Somewhat surprisingly, we found that the rates for formation of several native proteins in uncatalyzed systems containing GSSG and GSH are as great as with the "shuffle-ase" enzyme, suggesting that a substantial portion of biological thiol oxidations proceed by uncatalyzed exchange. While thiol-disulfide exchange of course results in no net change in the oxidation level of a system, catalytic linkage of thiol or disulfide to other redox systems provides a mechanism for achieving net changes.
Chemical Phenomena↗