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At least 127 records · Page 7Linked to original sources

PubMed2003

Evidence for third-harmonic generation in disguise of second-harmonic generation in extreme nonlinear optics.

In contrast with traditional nonlinear optics, a peak at the spectral position of the second harmonic of a laser can also be generated in an inversion-symmetric medium in the regime of extreme nonlinear optics. We describe the underlying mechanism of such third-harmonic generation in disguise of second-harmonic generation and compare theory with the optical as well as the radio-frequency spectra measured in recent experiments on thin ZnO films. The peak at twice the carrier-envelope offset frequency in the radio-frequency spectra is shown to be an unambiguous signature of such a process.

Journal Article↗

PubMed1978

The secondary cytotoxic response to trinitrophenyl (TNP) modified syngeneic lymphocytes: effectors generated in vitro differ from those generated in vivo.

Following priming in vivo, a secondary cytotoxic response to TNP modified syngeneic lymphocytes can be generated by restimulation either in vivo or in vitro. The secondary effectors generated in vivo show H-2 restricted cytotoxicity, in that only TNP modified syngeneic targets are lysed. However, the secondary effectors generated in vitro lyse both TNP modified syngeneic targets and TNP modified congenic targets which differ only at the major histocompatibility complex.

Animals↗

PubMed1999

Two-chain factor VIIa generated in the pericardium during surgery with cardiopulmonary bypass : relationship to increased thrombin generation and heparin concentration.

Several recent studies have proposed that coagulation is triggered during cardiopulmonary bypass surgery by extrinsic pathway activation involving factor VIIa generation, but the methodology was indirect. Therefore, 12 patients were studied during routine cardiac and cardiopulmonary bypass surgery. Samples were taken before, during, and after bypass from the perfusate, from the aorta (retrograde cardiac drainage), pericardium, and collected suction fluid originating from the whole operative field. These samples were analyzed by enzyme-linked immunosorbent assay for 2-chain factor VIIa, by prothrombin F1+2 assay, by thrombin-antithrombin (TAT) assay, and for heparin concentration. Factor VIIa, F1+2, and TAT levels in samples from the pericardium were greatly elevated (mean, 0.92 to 1.01, 227 to 334, and 399 to 526 microg/L, respectively; preoperative mean, 0.33, 32.3, and 1.90 microg/L, respectively; P<0. 05 for all), whereas levels in suction fluid were less consistently high. Factor VIIa and both F1+2 and thrombin-antithrombin levels in samples from the aorta, pericardium, and suction fluid were significantly correlated (r=0.57, P<0.001, n=111; and r=0.51, P<0. 001, n=105, respectively), and all were inversely correlated with heparin levels (r>-0.35, P<0.001, n>92). There was no evidence of factor VIIa generation in the circuit during bypass surgery, and both F1+2 and thrombin-antithrombin levels rose only approximately 2-fold, probably because heparin levels were higher than they were in the pericardium (P<0.05). We concluded that appreciable activation of factor VII occurs on the pericardium and that this is associated with increased thrombin generation. Ineffective local heparinization may be partly responsible. These results suggest that pericardium-induced activation of factor VII should be the target of anticoagulant strategies during cardiopulmonary bypass surgery.

Aged↗

PubMed1978

Superoxide generation by digitonin-stimulated guinea pig granulocytes. A basis for a continuous assay for monitoring superoxide production and for the study of the activation of the generating system.

Stimulation of guinea pig granolocytes by digitonin results in superoxide (O-2) generation. A continuous assay shows that there is a lag between the addition of digitonin and the onset of O-2 production. The rate of activation of the O-2 generating system is dependent upon the concentration of digitonin and the temperature. The final linear rate of O-2 production is affected by the concentration of digitonin, temperature, pH, and the presence of exogenous reduced pyridine nucleotides. Thus, factors which alter either the activation process or the activity of the O-2 generating system can affect O-2 production by stimulated granolocytes.

Animals↗

PubMed2001

Characterization of Norwalk virus GI specific monoclonal antibodies generated against Escherichia coli expressed capsid protein and the reactivity of two broadly reactive monoclonal antibodies generated against GII capsid towards GI recombinant fragments.

BACKGROUND: Norwalk virus causes outbreaks of acute non-bacterial gastroenteritis in humans. The virus capsid is composed of a single 60 kDa protein. In a previous study, the capsid protein of recombinant Norwalk virus genogroup II was expressed in an E. coli system and monoclonal antibodies were generated against it. The analysis of the reactivity of those monoclonal antibodies suggested that the N-terminal domain might contain more antigenic epitopes than the C-terminal domain. In the same study, two broadly reactive monoclonal antibodies were observed to react with genogroup I recombinant protein. RESULTS: In the present study, we used the recombinant capsid protein of genogroup I and characterized the obtained 17 monoclonal antibodies by using 19 overlapping fragments. Sixteen monoclonal antibodies recognized sequential epitopes on three antigenic regions, and the only exceptional monoclonal antibody recognized a conformational epitope. As for the two broadly reactive monoclonal antibodies generated against genogroup II, we indicated that they recognized fragment 2 of genogroup I. Furthermore, genogroup I antigen from a patient's stool was detected by sandwich enzyme-linked immunosorbent assay using genogroup I specific monoclonal antibody and biotinated broadly reactive monoclonal antibody. CONCLUSION: The reactivity analysis of above monoclonal antibodies suggests that the N-terminal domain may contain more antigenic epitopes than the C-terminal domain as suggested in our previous study. The detection of genogroup I antigen from a patient's stool by our system suggested that the monoclonal antibodies generated against E. coli expressed capsid protein can be used to detect genogroup I antigens in clinical material.

Antibodies, Monoclonal↗

PubMed2004

Cascaded wavelength conversions based on sum-frequency generation and difference-frequency generation.

A novel wavelength conversion scheme based on cascaded sum-frequency generation (SFG) and difference-frequency generation (DFG) is proposed and demonstrated in a MgO-doped LiNbO3 quasi-phase-matched waveguide. In this scheme, two pump wavelengths are set outside the communication band. It is shown that the same conversion efficiency can be achieved by use of two pump sources with lower output power (P1, P2) in this scheme compared with the conventional cascaded wavelength conversion technique based on second-harmonic generation and DFG with a single higher-power pump beam (P = P1 + P2) that is due to the use of a larger SFG nonlinear coefficient. The results significantly influence the selection of a suitable nonlinear interaction scheme for practical applications.

Journal Article↗

PubMed2005

Flt3 ligand-generated murine plasmacytoid and conventional dendritic cells differ in their capacity to prime naive CD8 T cells and to generate memory cells in vivo.

Mature dendritic cells (DCs) have the capacity to induce efficient primary T cell response and effector cell differentiation. Thus, these cells are a major tool in the design of various immunotherapeutic protocols. We have tested the capacity of different subsets of matured DCs pulsed with a peptide to induce the differentiation of naive CD8 T cells into memory cells in vivo. Flt3 ligand (FL) induces the differentiation of conventional DCs (cDCs) and plasmacytoid DCs (PDCs) from murine bone marrow precursors in vitro. After maturation, both subsets become strong stimulators of Ag-specific T cell responses in vitro. However, the in vivo T cell stimulatory capacity of these DC subsets has not been studied in detail. In the present study, we demonstrate that mature FL-generated DCs induce efficient peptide-specific CD8 T cell response and memory cell differentiation in vivo. This is mainly due to the cDC subset because the PDC subset induced only a negligible primary CD8 response without detectable levels of memory CD8 T cell differentiation. Thus, in vitro FL-generated mature cDCs, but not PDCs, are potent stimulators of peptide-specific CD8 T cell responses and memory generation in vivo.

Animals↗

PubMed1996

[Diagnosis of HCV infection by 3rd-generation ELISA in HCV-RNA positive hypertransaminasemic patients with 2nd-generation ELISA negative results].

To evaluate the improved sensitivity of 3rd-generation assays for the detection of ani-HCV antibodies in diagnosing cases of HCV infection, we have re-tested by 3rd-generation ELISA test (ELISA-3) serum samples from immunocompetent patients with chronic hypertransaminasemia who were HCV-RNA positive but tested negative with 2nd-generation ELISA (ELISA-2). Out of 21 HCV-RNA positive/ELISA-2 negative samples, 3 (14.3%) were ELISA-3 positive. Among the ELISA-3 reactive samples, two were indeterminate by RIBA-3 (one was reactive with c1 00 and the other with c22), and one was negative. These results demonstrate that even in the clinical setting ELISA-3 improves the diagnosis of HCV infection. The improvement seems to be related to a better reactivity of HCV peptides rather than to the inclusion of the new determinant NS5. However, the sensitivity of the tests for the detection of anti-HCV antibodies remains to be improved.

English Abstract↗

PubMedDate not supplied

[Consequences for posterity of two generations of an irradiation pregnant from females rats Wistar in small doses during a bookmark of reproduction system of fetuses development of posterity of the second generation and it reproduction function].

With the purpose of study of consequences for development and reproduction functions of posterity of the second generation from females rats Wistar of a total unitary gamma-irradiation in dozes 0.25; 0.5 and 1 Gy (capacity of a doze 0.03 sGy/s) on 10th day of pregnancy (the period of the onset of fetuses reproduction system development) is investigated more than 630 females, 1400 with the age of 19th days, and about 3200 young rats. The revealed deviations(rejections) in development of posterity of two generations parents, antenatal irradiated in not sterilizing dozes, in he period of a beginning of formation of reproduction system, them a variety at different dozes of radiating influence, shown as at posterity of the irradiated mothers, and fathers, testify about instability genoms in a line of generations requiring the account and acceptance of necessary measures for preservation normal genofund.

Animals↗

PubMed1979

Generation of memory cells. III. Antibody class requirements for the generation of B-memory cells by antigen--antibody complexes.

Immunizing mice with preformed antigen--antibody complexes is a highly effective means of generating B-memory cells. In the present study we have compared the capacity of mouse anti-dinitrophenyl (DNP) IgM, IgG1, IgG2 and IgA antibodies to generate DNP-specific memory, when given in complex with antigen (DNP-KLH: keyhole limpet haemocyanin). Two monoclonal IgM antibodies exerted no adjuvant effect, whereas a monoclonal IgA antibody was effective, IgG2 antibodies were a more powerful adjuvant than IgG1, regardless of whether anti-DNP or anti-KLH antibodies were used. Furthermore, the capacity of DNP-KLH--antibody complexes to localize in splenic lymphoid follicles could be ranked IgG2 greater than IgG1 greater than IgA; IgM complexes did not localize in follicles. These results correlate well with data (presented elsewhere) on the capacity of these different antibodies to activate mouse complement, and confirm that C activation is an essential requirement for both follicular localization of immune complexes, and for the generation of B-memory cells. Although activation of the alternative complement pathway is sufficient to effect both processes, the results with IgG2 antibodies raise the possibility that classical pathway activation may be more effective.

Animals↗

PubMedDate not supplied

[Thematics of the multi-generation family: an example of a 6- and 7-generation family].

By investigating multi-generational families, a number of family themes can be detected. This example of a six- and seven-generation family points to unique family relationships and themes, such as teenage pregnancy. The influence of societal changes on the development of a multi-generational family is described, as well as intergenerational changes with respect to family cohesion.

Aged↗

PubMed1980

In vitro generation of cytotoxic lymphocytes against radiation and radiation leukaemia virus-induced tumours. II. A radiation-induced thymoma generates cytyotoxic response in syngeneic but not in allogeneic lymphocytes.

A thymoma cell line (PXT), originally induced by X-irradiation in a C57Bl/6 mouse, was found capable of generating cytotoxic T lymphocytes (CTL) in a syngeneic mixed lymphocyte tumour culture (MLTC), but failed to stimulate allogeneic lymphocytes. Serologically defined H-2 antigens could readily be detected on PXT cells, which were also susceptible to lysis by alloreactive CTL generated against C57Bl/6 lymphoblasts or other thymomas of C57Bl/6 origin. These observations suggest that the PXT line lacks lymphocyte-activating determinants (LAD) essential for allosensitization but possesses other determinants enabling stimulation of syngeneic CTL, and that the cellular events leading to generation of anti-H-2 and anti-'modified self' CTL proceed along distinct T-cell differentiation pathways.

Animals↗

PubMed1980

Generation of a biologically active lipid from arachidonic acid by exposure to a superoxide-generating system.

A biologically active lipid was produced by incubating arachidonic acid with a superoxide-generating system consisting of xanthine oxidase plus acetaldehyde. The lipid proved to be a potent chemoattractant for human polymorphonuclear leukocytes and also was capable of inhibiting platelet aggregation induced either by arachidonic acid or by the endoperoxide analog, 9,11-azoprostanoid III. Generation of the biologically active lipid required the presence of all of the reactants, was time-dependent and could be inhibited by scavengers of superoxide, hydroxyl radicals, and singlet oxygen. Silica gel thin-layer radiochromatography demonstrated a single peak with biological activity, distinct from unaltered arachidonic acid. The biologically active lipid was most likely generated by the peroxidation of arachidonic acid. Biologically active products of arachidonic acid formed nonenzymatically by the action of oxygen-derived free radicals may play important roles in the mediation and modulation of inflammatory responses.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗

PubMed1993

[Comparative study of 1st generation versus 2d generation (CAVPE) combinations in intermediate and high-grade lymphomas].

PURPOSE: To compare four first generation chemotherapy regimes (FGR) used by GATLA in low and intermediate grade lymphomas. Versus a second generation regimen called CAVPE. PATIENTS AND METHODS: A group of 205 patients treated with FGR (79 with BACOP, 89 with COPP, 19 with CHOP, and 18 with CNOP), and 244 others treated with the combination of cyclophosphamide, doxorubicin, vincristine, prednisone and etoposide (CAVPE) were included. Two randomized phase III multicentric studies, COPP vs BACOPP and CHOP vs CNOP, as a whole group, were compared with the second generation scheme, CAVPE. All the patients with FGR received 6 monthly treatment courses, and the CAVPE patients were given 8 monthly courses. RESULTS: The median age was 55 years (18-85) for the FGR group and 51 years (15-79) for the CAVPE group. The stage distribution for both FGR and CAVPE groups was, respectively, as follows: II: 38 and 55 cases; III 80 and 84 cases; IV: 87 and 105 cases. No significant differences were found between both groups when comparing other characteristics of the patients, namely, sex, symptoms, mediastinal, abdominal or extranodal involvement, liver, spleen or bone-marrow infiltration, and bulky tumoural mass. The percentage of complete remission (CR) was 52% (107/205) in the patients treated with FGR, and 67% (163/244) in the CAVPE group (p < 0.001). The estimated probability of sustained first CR at 72 months was 38% for the FGR group and 54% for the CAVPE group (p = 0.0167), whereas 17% and 36%, respectively, of the evaluable patients were alive and well, with no signs of disease progression (p = 0.000). The 72-month survival was estimated in 32% and 51%, respectively, for each group (p = 0.0004). CONCLUSIONS: 1. CAVPE seems to offer better responses and disease-free survival in this non-selected group of low and intermediate lymphoma patients. 2. The better results in terms of CR and lower incidence of relapses attained with CAVPE with regard to FGR are probably related with a number of facts, such as the use of more aggressive drugs, higher doses, a better drug combination rationale, the inclusion of new drugs, such as etoposide, or a selection of the patients.

Adolescent↗

PubMedDate not supplied

Chemical vapor generation of Cu: optimization of generation media.

Acetic acid was used to enhance the efficiency of chemical vapor generation (CVG) of copper. The volatile product was formed at room temperature following merging of the sample solution with a flowing stream of 0.1% NaBH4; ICP-OES was used for detection. A precision of 1.6% RSD (n=11, 0.2 mg/L) was realized at sampling frequencies of about 90/h. A detection limit of 0.4 ng/mL (3sigma) was obtained. Sensitivity was enhanced approximately 8-fold over conventional pneumatic nebulization sample introduction. Compared with CVG in an optimized HCl or HNO3 medium, sensitivity was increased by an order of magnitude using acetic acid and the reductant concentration was reduced to only 10% of that required with HCl or HNO3. The generation efficiency was estimated to be 18% or 70%, depending on the method used to evaluate it. The methodology was successfully used to the determine copper in human hair and low alloy steel certified reference materials.

Acetic Acid↗

PubMed1977

Effect of tumor cells on the generation of cytotoxic T lymphocytes in vitro. I. Accessory cell functions of mouse tumor cells in the generation of cytotoxic T lymphocytes in vitro: replacement of adherent phagocytic cells by tumor cells or 2-mercaptoethanol.

In agreement with previous reports, the primary in vitro response to alloantigens has been shown to be dependent on the presence of macrophages (Mphs). Splenocytes extensively depleted of adherent phagocytic cells did not generate cytotoxic T lymphocytes, and this activity could be completely restored by small numbers of adherent peritoneal cells (accessory cells). Either P388D1 (Mph-like tumor), P388 ("null" tumor) or P815 (mastocytoma) tumor cells, or 2-mercaptoethanol, could completely replace the accessory function normally mediated by accessory cells. These tumor cells did not non-specifically "enhance" the cytotoxic activity generated with normal nondepleted spleen cells. The restored cultures maintained killing specificity to H-2 targets which was mediated by effector T cells as shown by sensitivity to anti-theta and complement. Therefore, Mphs seem not to be the sole cells capable of mediating an accessory function in a primary response to alloantigens in vitro.

Animals↗

PubMed1981

Generation of effector cells from T cell subsets. III. Synergy between Lyt-1 and Lyt-123/23 lymphocytes in the generation of H-2-restricted and alloreactive cytotoxic T cell.

Lyt-123/23 and Lyt-1 T cell subsets, positively selected by separation on the fluorescence-activated cell sorter, were tested in vitro for their role in the generation of H-2-restricted and alloreactive cytotoxic T cells. It is shown that in the proliferation assay, both T cell subsets responded equally well to H-2 and non-H-2 antigens (H-Y), respectively. In contrast, none of the selected Lyt subsets, but only the mixed population containing Lyt-1 and Lyt-123/23 lymphocytes gave rise to both H-2-restricted (anti H-Y, anti-trinitrophenyl) and alloreactive (anti-H-2) cytotoxic lymphocytes. The data imply an essential role of Lyt-1 cells as inducers or helpers in the generation of all cytotoxic lymphocytes from their precursors in the Lyt-123/23 pool.

Animals↗

PubMed1983

Initiation of focal hyperplastic hepatic lesions by transplacental administration of ethylnitrosourea in rats of F1 generation, and no transmission of the effect to F2 and F3 generations.

Administration of ethylnitrosourea (ENU) to pregnant rats in the late stage of gestation has been known to have a mainly neurocarcinogenic action on the progeny. However, when transplacental administration of ENU was combined in postnatal life with a brief dietary exposure to 2-acetylaminofluorene (2-AAF) and a two-thirds partial hepatectomy, numerous focal hyperplastic lesions of gamma-glutamyltranspeptidase (GGT)-positive hepatocytes emerged in the liver of the progeny. On the other hand, rats of F2 generation born of F1 parents and F3 rats born of F2 parents showed no increase in the incidence of hepatic lesions after treatment with the same dietary regimen. It was suggested that direct interaction between fetal liver cells and the carcinogen is important for occurrence of initiated hepatocytes and that the initiation effect on rat liver by ENU does not persist in the descendants of F2 and F3 generations.

2-Acetylaminofluorene↗