Biomedical subjects
Publications and source records attributed to S Jiang.
Using biotinylated human Y-specific DNA probe PHY2.1 and Cos 84, we carried out Southern and dot hybridization with human DNA from artificially aborted chorionic villi, and with DNA of peripheral lymphocytes from normal male and female. The results show that PHY2.1 may be applied in prenatal sex identification both by Southern and by dot hybridization but with Cos 84, only Southern hybridization could be used.
The development of the photoreceptors of human embryos and fetuses dating from 7 weeks to term were studied. The outer segments of rods and cones began to form at the seventh month. The arrangement of the newly formed discs were not regular, but at term they were arranged parallel to each other and perpendicular to the long axes of the outer segments. At the 9th month, no phagosome containing discs was seen in the pigment epithelial cells, but they were discerned in those of the term fetuses.
The results of combined use of ultrasonography and beta-hCG determination for diagnosis of pelvic lesions of malignant trophoblastic disease in 73 cases were reported. Abnormal ultrasonograms and elevated beta-hCG levels were found in 53 of 55 cases of invasive mole and all 20 cases of choriocarcinoma. The location and extent of the pelvic lesions were clearly defined by ultrasonography. Moreover, there was a high correlation rate between ultrasonograms and beta-hCG levels. Surgico-pathological diagnosis was available in 17 cases. Based on these data, the authors emphasize that in improving the accuracy of diagnosis and locating the pelvic lesions ultrasonography in combination with beta-hCG determinations should be used as a routine procedure in suspected cases of pelvic lesion of malignant trophoblastic disease.
As a tumor of the body surface, theoretically there should be no problem to achieve an early diagnosis and early treatment in carcinoma of the vulva. However, factually it is not always the case. Missed diagnosis is not uncommon and extensive local invasion in late cases may lead to very poor prognosis in patients treated by regular radical vulvectomy. Urethral involvement by vulvar cancer constitutes a special challenge to the gynecologic oncologists. The authors have developed an improved Gersuny-Lowsley's operation in addition to radical vulvectomy to preserve the function of urination and defecation after complete resection of the involved urethra. This modified procedure has been carried out in 10 patients with satisfactory functional control in 8 cases. A follow-up study for 1-10 years reveals no evidence of recurrence in all 10 cases.
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CTL and NK cells produce a cytolytic pore-forming protein (perforin, cytolysin) localized in their cytoplasmic granules. These cytotoxic cells are resistant to killing mediated by other lymphocytes and by purified perforin. A membrane factor, known as homologous restriction factor (HRF), has been suggested to confer protection to different cell types against both C- and perforin-mediated lysis. The granules of human large granular lymphocytes have been reported to contain, in addition to perforin, a soluble HRF activity that can be eluted from anion-exchange columns at 115 mM NaCl. Here, we report that a soluble HRF activity is absent in the granules or the cytosol of murine CTL and human NK cells. Our data indicate that the inhibition attributed to HRF could be explained by exogenous EDTA added during granule fractionation. EDTA was shown to bind to Mono Q and to elute at 90 to 120 mM NaCl. A second perforin-inhibitory activity was also eluted from such a column. However, it was present in preparations obtained not only from CTL and NK cells, but also from some perforin-susceptible tumor cell lines, indicating that it has nonrestricted distribution and suggesting that it is probably irrelevant to the perforin-protection mechanism. Our results argue against a role for soluble granule HRF or other soluble factors in mediating resistance of cytotoxic lymphocytes against perforin-mediated lysis.
Previous reports have suggested that a 65 kDa membrane protein, termed homologous restriction factor (HRF), in addition to protecting erythrocytes (E) against lysis by homologous complement (C), may also be involved in protecting cytolytic lymphocytes against lysis mediated by a pore-forming protein (PFP/perforin), one of their own lytic mediators. Here, we used HRF-deficient type III E of patients with paroxysmal nocturnal hemoglobinuria (PNH) to study their susceptibility to lysis mediated by homologous C and perforin, and compared it with lysis of HRF-bearing control or PNH type I E. We show that type III E of PNH patients are indeed more susceptible to lysis mediated by homologous C than control or type I E, but they are as susceptible to perforin-mediated lysis as type I E. In addition, all human E (type I or III) tested here are equally susceptible to lysis mediated by either human (homologous) or murine (heterologous) perforin. By immunoblot analysis, we confirm that type III E, in contrast to type I E, were deficient in the 65 kDa HRF. These results support the notion that homologous species restriction is seen in the C- but not in the lymphocyte perforin-system and argue against an active participation of HRF in protecting cells from perforin-mediated lysis.
CTL and NK cells cultured in vitro are known to produce a cytolytic pore-forming protein (PFP, perforin) localized in their cytoplasmic granules. Using purified perforin, we showed here that both cloned CTL and primary killer cell populations, including allospecific CTL, NK/lymphokine-activated killer cells, and MHC-non-restricted CTL, were more resistant to perforin-mediated killing than other lymphocyte populations and cell types. Similar results were obtained with both murine and human cytolytic lymphocyte populations. Resistance of killer cells to perforin correlated in general with their cytolytic capability. Thus, cells that have acquired competence to kill after stimulation with Con A, IL-2, or leukocyte-conditioned medium, were also the more resistant cells. IL-2-independent CTL lines and hybridomas derived in our laboratories could be triggered to become cytotoxic and perforin resistant by short-term stimulation with various cytokines, indicating that the acquisition of resistance to perforin-mediated lysis was independent of cell proliferation. Activation of one IL-2-independent CTL line with IL-2 also resulted in enhanced production of perforin and in enhanced serine esterase activity. The acquisition of cell resistance to perforin by these IL-2-independent cell lines after activation with stimulatory reagents was independent of protein and RNA neosynthesis: emetine, cycloheximide, and actinomycin D, while effectively blocking the incorporation of [35S]methionine into cell proteins, did not affect the induced increase in perforin resistance.
A pore-forming protein (PFP, perforin or cytolysin) has been found in the cytoplasmic granules of cytotoxic T lymphocytes (CTL) and natural killer (NK) cells. Extraction of granules with high-salt buffers or by freezing-and-thawing results in the release of perforin, which occurs only when the buffer pH is above 7.0. While high-salt extraction and freezing-and-thawing of granules at low pH (below 7.0) do not result in perforin release, these treatments render granules susceptible to a subsequent incubation with low-salt buffers (pH 7-8) that then solubilizes perforin completely. Granules may thus have been made leaky by high-salt extraction or freezing-and-thawing that may occur regardless of the buffer pH, while dissociation of perforin from granules may be exquisitely pH-sensitive. Freezing-and-thawing intact CTL and NK cells in physiological buffers with pH in the range of 7-8 (but not below 7) also causes release of perforin activity to the cell supernatant, thus providing a simple procedure by which perforin activity can be quantitated in small cell samples. Our results suggest that during lymphocyte-mediated killing, the extracellularly released perforin may rapidly dissociate from granules as a result of pH change and, in the process, become cytolytically active.
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