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11.
Aldo Ferretti Vincent P. Flanagan Joseph T. Judd Padmanabhan P. Nair Philip R. Taylor 《The Journal of nutritional biochemistry》1993,4(12)
Dietary supplementation with a fish oil concentrate (FOC) reduced the endogenous synthesis of prostacyclin (PGI2), as measured by the excretion of its major urinary catabolite, 2,3-dinor-6-oxo-PGF1α (PGI2-M). Thirty-four healthy men (24–57 years old) were given controlled diets and supplements that provided 40% of the energy from fat and a minimum of 22 mg/d of α-tocopherol for two consecutive experimental periods of 10 weeks each. During the experimental periods, the men received capsules containing 15 g/d of a placebo oil (PO) (period 1) or 15 g/d of the FOC (period 2). In addition to the PO or FOC, capsules contained 1 mg of α-tocopherol per g of fat as an antioxidant. The average daily excretion of PGI2-M during the last week of FOC supplementation (period 2) was 22% less (P = 0.0001) than at the end of the first period. These results are at variance with those reported in comparable human studies conducted by other investigators during the middle and late 1980s. A 20% reduction (P = 0.003) in the 11-dehydrothromboxane B2 to 2,3-dinor-6-oxo-PGF1α excretion ratio at the end of period 2 in this study demonstrates that a shift of the n-6 to n-3 polyunsaturated fatty acid ratio from 12.5 to 2.3 brings about a substantial modulation of the eicosanoid system. 相似文献
12.
Alfonso Pompella Caterina Cambiaggi Silvia Dominici Aldo Paolicchi Roberto Tongiani Mario Comporti 《Histochemistry and cell biology》1996,105(3):173-178
Confocal laser scanning fluorescence microscopy coupled to image analysis was employed in order to develop and evaluate procedures for the appraisal at the single-cell level of: (1) protein-bound 4-hydroxynonenal, the specific product of membrane peroxidation (by means of immunocytochemistry with biotin-avidin revelation); (2) protein oxidation (by reaction of protein carbonyls with 2,4-dinitrophenyl-hydrazine followed by immunocytochemistry of dinitrophenyl moieties); and (3) cellular protein thiols (by direct alkylation of sulfhydryl groups with thiol-specific fluorescent reagents possessing different cell permeabilities). The procedures proved able to reveal the subcellular distribution of cytochemical parameters useful as indices of oxidative stress conditions, and may allow redox phenotyping of isolated cells, which would provide an efficient tool in selected experimental models. 相似文献
13.
Alfonso Pompella Aldo Paolicchi Silvia Dominici Mario Comporti Roberto Tongiani 《Histochemistry and cell biology》1996,106(3):275-282
A number of studies indicate that cell proliferation can be modulated by changes in the redox balance of (soluble and protein)
cellular thiols. Free radical processes, including lipid peroxidation (LPO), can affect such a balance, and a role for LPO
in multistage carcinogenesis has been envisaged. The present study was aimed to assess the relationships between the protein
thiol redox status and the LPO process in chemically induced preneoplastic tissue. The Solt-Farber's initiation-promotion
model of chemical carcinogenesis in the rat liver was used. In fresh cryostat sections, preneoplastic lesions were identified
by the reexpression of γ-glutamyltranspeptidase (GGT) activity. In serial sections, different classes of protein thiols were
stained; in additional sections, LPO was elicited by various prooxidant mixtures and determined thereafter by the hydroxynaphthoic
hydrazide-Fast Blue B procedure. The incubation of sections in the presence of chelated iron plus substrates for GGT activity
leads to the development of LPO in selected section areas closely corresponding to GGT-positive lesions, indicating the ability
of GGT activity to initiate LPO. Protein-reactive thiols, as well as total protein sulfur, were decreased by 20–25% in cells
belonging to GGT-positive preneoplastic nodules, suggesting the occurrence of oxidative conditions in vivo. The incubation
of additional adjacent sections with the prooxidant mixture H2O2 plus iron(II), in order to induce the complete oxidation of lipid present in the section, showed a decreased basal concentration
of oxidizable lipid substrate in GGT-rich areas. The decreased levels of both protein thiols and lipid-oxidizable substrate
in GGT-positive nodules suggest that the observed GGT-dependent path-way of LPO initiation can be chronically operative in
vivo during early stages of chemical carcinogenesis, in cells expressing GGT as part of their transformed phenotype. 相似文献
14.
Five novel representatives of the yeast genus Candida isolated from advanced stages of wood degradation from fallen trunks of Eucryphia cordifolia Cav., Laurelia sempervirens Weim., Laurelia philippiana Weim., Nothofagus dombeyii (Mirb.) Blume, and Nothofagus obliqua (Mirb.) Blume, in the evergreen rainy Valdivian forest of southern Chile, are described and illustrated. They clearly differ from all accepted Candida species to warrant their establishment as five new species of yeasts: Candida coipomensis sp. nov., Candida ralunensis sp. nov., Candida laureliae sp. nov., Candida osornensis sp. nov., and Candida llanquihuensis sp. nov. 相似文献
15.
Four unusual Apiotrichum, isolated from decayed wood of Eucryphia cordifolia Cav., Nothofagus obliqua (Mirb.) Blume, and Laurelia sempervirens Wein., one of which was also isolated from the intestinal tract of Scaptomyza multispinosa Malloch (Diptera), are described and illustrated. These species differ from all the accepted Apiotrichum species (1–3) to warrant their establishment as four new species: Apiotrichum eucryphiae, Apiotrichum osvaldii, Apiotrichum futronensis and Apiotrichum nothofagi. 相似文献
16.
Two unusual species of Candida and one variety of one of them, isolated from decayed wood (palo podrido) (12) in the ultimate stages of degradation, are described and illustrated. They differ sufficiently from all accepted Candida species to warrant their establishment as two new species and one variety: Candida railenensis, Candida bertae, and Candida bertae var. chiloensis.The DNA base composition of these yeasts was not calculated, since our laboratory is not properly equipped for that purpose. 相似文献
17.
A deterministic predator-prey model is presented for describing the dynamics of a solid tumor in the presence of a specifically
reactive lymphocyte population which is stimulated by, and antagonistic to, the tumor. The qualitative behavior of the solutions
is developed and briefly compared to the results of transplantation experiments. Although the model is primitive, it leads
to predictions that are in general agreement with observation and intuitive expectations. In particular, it is found that:
(1) very low levels of transplanted tumor will not survive in the recipient. (2) At somewhat higher levels, tumor growth will
be uncontrolled in the syngeneic recipient. However, immune intervention if early enough, can lead to control and elimination
of the tumor. (3) At still higher levels of transplanted tumor, no amount of immune intervention will be effective in controlling
the tumor. (4) If the recipients immune system is suppressed prior to transplantation, or is debilitated for any reason, the
chance that the tumor will grow increases. (5) If the recipients immune system is stimulated prior to transplantation, the
chance of tumor survival decreases. (6) The survival of the tumor is much more sensitive to changes in tumor parameters (for
example, antigenicity) than in lymphocyte parameters. In addition it makes the unintuitive prediction that (7) There areisolated instances under which anincrease in the number of lymphocytes canincrease the chance of tumor survival. 相似文献
18.
General formulation of stochastic single- and multi-compartment reversible systems with time-dependent transitions is made.
The correspondence between the stochastic mean and the deterministic value is established in case of time-dependence and it
is shown how the consequence of this can be utilized to compute the distribution and the moments of each individual compartment
of the system. A two-compartment reversible system previously proposed by Cardenas and Matis (1975a) is analyzed on the basis
of the theory. 相似文献
19.
Keith Paige Melanie Palomares Patricia A. D’Amore Susan J. Braunhut 《In vitro cellular & developmental biology. Animal》1991,27(2):151-157
Summary The growth of the endothelial cell (EC) is tightly regulated throughout the body. Many factors have been implicated in modulating
EC growth including diffusible compounds, cell-to-cell interactions, and the extracellular matrix (ECM). Retinol, or vitamin
A alcohol, has recently been shown to inhibit the growth of bovine capillary ECs, in vitro. Retinoids are known to modify
ECM in other cell systems, and pure ECM components have been shown to effect EC growth rates. We, therefore, examined the
role of the matrix in the retinol-induced inhibition of ECs. Cell-free matrices from control and vitamin A-treated ECs were
prepared by removing cells with EGTA treatment after 7 d of culture. Matrix proteins were analyzed by solubilizing the matrices
in 5M quanidine-HCl and performing Western blot analysis using specific antibodies to matrix proteins. In isolating the ECM, we
observed that retinol-treated cultures of ECs were resistant to EGTA removal; retinol-treated ECs required twice the exposure
time to EGTA to detach from their matrix than did controls cells. Western blot analysis of matrix proteins derived from control
and retinol-treated EC cultures demonstrated a 1.6-fold increase in lamininβ chains and a 2.5-fold increase in fibronectin in the ECM of retinol-treated EC compared to control cell matrix. Functional
properties of these matrices were assessed by plating control and Day 6 retinol-treated ECs onto the matrices and measuring
attachment and growth by determining cell numbers at 24, 72, and 144 h. These studies revealed that control cells attached
in greatest numbers to a control matrix whereas retinol-treated ECs preferentially attached to a matrix derived from retinol-treated
cells. Furthermore, control ECs which grew rapidly on a control matrix were growth inhibited on a retinol-derived matrix.
These data indicate that vitamin A treatment of ECs effects both their phenotype and influences the composition and the functional
properties of their underlying ECM. These studies also demonstrate that alterations of the matrix are at least in part responsible
for the growth inhibition of EC by retinol. 相似文献
20.
Concetta Compagno Aldo Tura Bianca Maria Ranzi Enzo Martegani 《Applied microbiology and biotechnology》1992,36(4):535-537
Summary One of the methods commonly used for manufacturing fructose 1,6-diphosphate is based on the enzymatic phosphorylation of glucose with inorganic phosphate using permeabilized brewer's yeast cells. Our results demonstrate that a substantial improvement in the yield of bioconversion can be achieved using fed-batch-grown Saccharomyces cerevisiae cells. Under an appropriate glucose and phosphate to cell ratio the efficiency of bioconversion reaches 70% of the theoretical value.
Offprint requests to: C. Compagno 相似文献