Background: Among all hematologic malignancies, B-cell chronic lymphocytic leukemia (BCLL) has the highest familial clustering (three-to sevenfold increase), strongly suggesting a genetic component to its etiology. Familial BCLL can be used as a model to study the early pathogenesis of this disease.Methods: We examined nine kindreds from the National Cancer Institute's Familial BCLL Registry, consisting of 19 affected members with BCLL and 33 clinically unaffected first-degree relatives. Flow cytometric immunophenotyping to detect a B-cell monoclonal lymphocytosis (BCML) was performed. Monoclonality was confirmed by polymerase chain reaction analysis of whole blood DNA. Cell cycle analysis for aneuploidy was conducted.Results: In all affected individuals, we observed the classic BCLL CD5/CD19/CD20/CD23 immunophenotypic patterns. Six of the 33 unaffected individuals (18%) had evidence of BCML. Additional individuals (13/33, 39%) showed some other abnormality, whereas 14 individuals (42%) were normal. Based on an estimated prevalence of 0.7% for BCML in the general population, the finding of six subjects (18%) with clonal abnormalities in this relatively modest sample was significantly greater than expected (i.e., 18% vs. 0.7%, P < 5.7 ؋ 10
A 3‐yr study of an aged population of American ginseng revealed four morphological classes among plants 1‐18 yrs old. The youngest and smallest plants had a single prong of 3‐5 leaflets and the oldest had four prongs with up to 20 leaflets. Age was positively correlated with prong and leaflet number. Prong development was linear, but not annual, i.e., a two‐pronged plant formed from the single prong stage on an average only after 4.5 years, a third prong arose after 7.6 years, and the fourth prong after 13.5 years. All one‐pronged plants were juveniles and, depending on the year, 22‐44% of two‐pronged plants were also juveniles. After the formation of an inflorescence during the two‐pronged stage, flowering was annual thereafter. Flower number per inflorescence was correlated with morphological class and age. Most plants that developed flowers formed fruit (80‐89%), except during the summer of 1980 when only 47% of flowering plants successfully matured fruit in a season typified by low precipitation and humidity, and high temperature. Younger adults in particular were more susceptible to failure in producing propagules and to earlier annual abscission under these stressful conditions than older members of the population. In fact, 53% of all flowering plants failed to develop fruit in 1980 compared to only 14% and 21% the previous 2 yrs. Seed survival was low and variable, the long afterripening period undoubtedly contributing to this vulnerable stage in the life cycle. Once germinated and established, however, seedling survival and development to adulthood, as well as adult survivorship, were high (97%). Even though a long‐lived, woodland geophyte, year‐by‐year fluctuations in reproductive capacity, seed germination, and time of aerial stem abscission were marked. Annual growing‐season dormancy, previously reported as a general phenomenon for American ginseng, was not found.
A new procedure is reported for high-yield isolation of guard cell protoplasts from Viia faba L. Delayed Light emission and P700 content plus absorption and fluorescence emission spectra of these protoplast extracts are reported. It is concluded that both photosystems are present. The presence of photosystem II 12Step 2. The leaf pieces were infitrated under reduced pressure with enzymic digestion medium consisting of 150 ml 0.3 M mannitol, 10 mm sodium ascorbate, 10 mm CaCl2, 4% (w/v) Cellulysin (pH 5.5). Incubation was for 1 h at 30 C in a 1-liter flask in a shaker bath (60 5-cm excursions/min).Step 3. One hundred fifty ml 0.7 M mannitol was added and incubation was continued for 1 h.Step 4. Digestion was interrupted by pouring the material over a 295-,um screen (Nitex) and washing with 0.7 M mannitol containing 10 mm sodium ascorbate. Epidermal strips (coming from both surfaces) and vein nets retained on the screen were transferred to 0.7 M mannitol containing 10 mM sodium ascorbate. Then the epidermal strips were manually separated from the vein nets and transferred to a separate container. The strips had few adhering mesophyll cells, but epidermal cells were intact.In some experiments, mesophyll cells which passed through the screen were carried through steps similar to the remainder of the isolation procedure and used as controls.Step 5. Digestion was continued for I h as in Step 2 except (a) mannitol was increased to 0.7 M, (b) volume was reduced to 100 ml, and (c) shaker-bath speed was reduced to 30 excursions/min.Step 6. The strips were collected and washed as in Step 4. If microscopic examination showed contaminating cells, Steps 5 and 6 were repeated.Step 7. Digestion was continued until guard cell protoplasts were released (about 3 h). These protoplasts were isolated by passage through a cascade of screens (nominally 295, 166, and 20 pm) and collected by centrifugation (lSOOg, 5 min). The protoplasts were washed three times with 0.7 M mannitol containing 10 mM sodium ascorbate and examined for purity.Comments. Isolation of guard-cell protoplasts has been reported (25,32, 43
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