Phytosulfokine (PSK), a 5-amino acid sulfated peptide that has been identified in conditioned medium of plant cell cultures, promotes cellular growth in vitro via binding to the membrane-localized PSK receptor. Here, we report that loss-of-function and gain-of-function mutations of the Arabidopsis (Arabidopsis thaliana) PSK receptor gene (AtPSKR1) alter cellular longevity and potential for growth without interfering with basic morphogenesis of plants. Although mutant pskr1-1 plants exhibit morphologically normal growth until 3 weeks after germination, individual pskr1-1 cells gradually lose their potential to form calluses as tissues mature. Shortly after a pskr1-1 callus forms, it loses potential for growth, resulting in formation of a smaller callus than the wild type. Leaves of pskr1-1 plants exhibit premature senescence after bolting. Leaves of AtPSKR1ox plants exhibit greater longevity and significantly greater potential for callus formation than leaves of wild-type plants, irrespective of their age. Calluses derived from AtPSKR1ox plants maintain their potential for growth longer than wild-type calluses. Combined with our finding that PSK precursor genes are more strongly expressed in mature plant parts than in immature plant parts, the available evidence indicates that PSK signaling affects cellular longevity and potential for growth and thereby exerts a pleiotropic effect on cultured tissue in response to environmental hormonal conditions.
The Zn-alpha 2-glycoprotein (Zn-alpha 2-GP) is present at a high concentration in the seminal plasma and at significant levels in other human body fluids. Its precise localization, however, has remained unclear, as well as its physiological and pathological significance. The present study reports the immunohistochemical localization of this protein in normal adult human tissues. Localization of the reactive product to anti-human plasma Zn-alpha 2-GP antibody was demonstrated in the following cells: luminal and basal cells of the prostate gland, luminal epithelial cells of the acini and of some ducts of the mammary glands, luminal cells of the secretory portion of the eccrine and apocrine sweat glands, serous cells of the salivary, tracheal, and bronchial glands, acinar cells of the esophageal glands, exocrine acinar cells of the pancreas, hepatocytes of the liver, and epithelial cells of the proximal and distal tubules in the kidney. The present results suggest that Zn-alpha 2-GP exerts some unknown but fairly widespread exocrine function and may be produced in the various epithelial cells tested. Hepatocytes are also suggested to be a source of the protein in the blood plasma.
The gold standard for breast cancer treatment is surgery, but many women may desire to avoid surgery if possible. The purpose of this study was to evaluate whether breast cancer could be cured with modern sophisticated radiation techniques with good cosmetic outcome. We have treated 18 patients with operable breast cancer by conventional whole-breast irradiation followed by stereotactic body radiotherapy (primary tumor only) or intensity-modulated radiotherapy (tumor plus axillary nodes) boost. The planned doses were 50 Gy in 25 fractions, 18 to 25.5 Gy in 3 fractions, and 20 Gy in 8 fractions, respectively, for the 3 modalities. Stereotactic body radiotherapy was delivered with 7 to 9 coplanar and noncoplanar fixed beams, and intensity-modulated radiotherapy was given by tomotherapy. Chemotherapy and/or hormone therapy was used depending on the stage and receptor status. In 9 recent patients, hydrogen peroxide was intratumorally injected twice a week before whole-breast irradiation. All treatments were well tolerable and there were no grade ≥3 toxicities. With a median follow-up period of 35 months (range, 8-120 months), only 1 patient developed local recurrence and 2 patients developed distant metastasis. Overall survival, progression-free survival, and local control rates were 93%, 85%, and 92%, respectively, at 3 years. In 50% of the patients, the irradiated breast became better rounded, and the position of the nipple of the irradiated breast became ≥1 cm higher compared to that of the unirradiated breast. Thus, the treated breasts may be more aesthetically favorable than before irradiation in these patients. This may become a treatment option for patients with operable breast cancer.
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