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91.
Evidence from morphology and anatomy (including embryology), as well as from palynology, chemistry and cytology, indicates thatHydrastis is quite divergent from Ranunculaceae (in which the genus has been most often included) as well as from both Glaucidiaceae and Berberidaceae. Distinctive features ofHydrastis, which demarcate it from Ranunculaceae but which are sometimes shared by Berberidaceae, are: the unique mode of origin of the vascular supply to stamens and carpels; the micropyle being formed by both integuments; the xylem not V-shaped in cross section; scalariform vessel perforations present; haploid chromosome number 13; pollen tectum consisting of a compound layer of striae; leaf mesophyll not differentiated; the unique course of stem medullary bundles; D-galactose present. Its distinctive higher haploid chromosome number, as well as its many less-specialized character states (in floral structure, leaf anatomy, and xylem and vessel morphology), suggest thatHydrastis is a relictual primitive group which diverged early from a common ancestral stock of Ranunculaceae, Berberidaceae and probably of Circaeasteraceae; at least some of the features shared byHydrastis and one or another of the families concerned seem to be a heritage from their common ancestor. We propose a reestablishment of a monotypic family, Hydrastidaceae.  相似文献   
92.
Summary A new type of collagen surface for use with cultures of peripheral nervous system cells is described. Collagen is derivatized to plastic culture dishes by a cross-linking reagent, 1-cyclohexyl-3-(2-morpholinoethyl)-carbodiimide-metho-p-toluenesulfonate (carbodiimide), to form a uniform and durable surface for cell attachment and growth that allows dry storage, long-term culture, and improved microscopy. Surfaces of collagen derivatized to plastic were compared to surfaces of adsorbed or ammonia-polymerized collagen in terms of collagen binding and detachment, growth by dorsal root ganglion cells, and electron microscopy appearances. Derivatized collagen surfaces retained more collagen and showed much less evidence of degradation and cellular damage over periods of many weeks than did conventional adsorbed surfaces. Long-term survival of cells on derivatized collagen was far superior to that on the other surfaces, with almost 90% of cultures still viable after 10 wk. Transmission electron microscopy showed an organized layer of single fibrils that supported cell growth well, and scanning electron microscopy demonstrated an increased uniformity of derivatized collagen surfaces compared to ammoniated collagen surfaces. Applications for this improved substrate surface are discussed. This work was supported by the Leopold Schepp Foundation, the Dysautonomia Foundation, National Institutes of Health Grants NS14768 and NS11237, and Institutional Core Grant HD06276.  相似文献   
93.
Twenty-three individuals from various disease groups and normal controls were identified by immunofixation with anti-C4, C4-dependent lysis, determination of Rg (Rodgers) and Ch (Chido) phenotypes, and immunoblotting with C4-specific mouse monoclonal antibody. We found that one haplotype predominates with the C4B * 5 allele, HLA-A11, B22(55), Cw3, Bf * S, C4A * 4B * 5, which also carries the Ch 1,–2, 3 haplotype. The B5 allotype was also found with HLA-1360, HLA-1335 in Caucasoids, and HLA-B18 in non-Caucasoids; these carried the Ch –1, –2, –3 haplotype. Our results are in accord with an earlier report of two B5 subtypes, B5Rg+ and B5Rg (Roos et al. 1984). The specificity of the mouse monoclonal antibodies IC4 and 21312 had been previously related to C4A and C4B, respectively, but our results suggest that they relate more closely to Rg and Ch determinants.  相似文献   
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95.
Summary Anthraquinones produced by suspension cultures of Cinchona ledgeriana are released into the medium, which becomes saturated with products late in the growth cycle. When a high affinity polymeric adsorbent, such as the macro-reticular Amberlite XAD-7, is added to the culture the concentration of anthraquinone in the medium is maintained at a low level and production may be stimulated 15-fold, yielding up to 20 mg/1/day. More than 90% of the product is released from the cells. For maximal yields it is shown that both the amount of adsorbent used and the time after sub-culture at which it is added to the system are critical. The value of such a method for product recovery from immobilised cells is discussed.  相似文献   
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97.
Increased longevity and recently intensified emphasis on gerodontology mandate that dental students'exposure to clinical care of the elderly be enhanced. The extent to which individual students can be exposed to geriatric dental care depends on the availability of elderly patients to dental school clinics and the treatment needs of these patients. The purposes of this study were (1) to determine the dental treatment needs of geriatric patients who seek care at a dental school, and (2) to ascertain if differences exist between the needs of older versus relatively young geriatric patients. Data collected on 128 elderly patients during a three month period indicate that 57% of the aged were either edentulous at examination or treatment planned to become edentulous and receive two full dentures. The remaining 43% were treatment planned to remain dentulous and receive therapies other than full upper and lower dentures. More older geriatric patients required full dentures than their younger cohorts. More young elderly required prophylaxes, scalings, root planing therapy, dental restorations, and partial dentures. Additional to their denture requirements, aged patients appear to have sufficient non-prosthetic needs to allow for meaningful gerodontic experience by students.  相似文献   
98.
99.
Translation of encephalomyocarditis virus RNA in rabbit reticulocyte lysates in the presence of N-formyl-[(35)S]methionine-tRNA(f) (Met) revealed that a small polypeptide is cleaved from the N-terminus of the capsid protein precursor, preA, by virus-coded protease activity. Therefore, this N-terminal segment comprising the translation initiation site is not conserved in any of the mature capsid proteins.  相似文献   
100.
Abstract: The combined techniques of HPLC and radioimmunoassay were used to identify and quantitate enkephalin-related peptides in the guinea pig hippocampus. Both met- and leu-enkephalin were identified, in approximately a 2:1 ratio, as well as a third enkephalin-like molecule that is neither met- nor leu-enkephalin. The third enkephalin elutes earlier than met- or leu-enkephalin from a reversed-phase column, has a molecular weight similar to the other enkephalins, and is as active as these enkephalins are in inhibiting binding of labeled opiates to rat brain membranes. All regions of the hippocampus (dentate gyrus, CA1–2, CA3–4, and subiculum) contain all three immunoreactive peptides. Immunocytochemical techniques, using antisera raised against met-enkephalin, show with one antiserum immunoreactivity in the granule cell-mossy fiber system, and with the other scattered immunoreactive cells mostly in the CA2 region. Enkephalins are not confined to the mossy fiber system, as previously suggested, but may be a component of another hippocampal innervation.  相似文献   
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