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Isolation of two populations of sperm cells and microelectrophoresis of pairs of sperm cells from pollen tubes of tobacco (Nicotiana tabacum) 总被引:1,自引:1,他引:0
Prior research has indicated that the two sperm cells of Nicotiana tabacum are dimorphic, suggesting that they may participate in preferential fertilization during in vivo fusion with the egg and
central cells. To probe the mechanism of potential preferential fertilization in this plant, it will be necessary to use modern
sensitive molecular techniques. For this purpose, two individual populations of two sperm cells, constituting the Svn (associated
with the vegetative nucleus) and Sua (unassociated with the vegetative nucleus), were isolated in the thousands from tobacco
pollen tubes with a micromanipulator as a preliminary step toward research on gametic recognition using molecular techniques.
Microelectrophoresis of paired sperm cells from a single pollen tube was conducted at different developmental stages. Sperm
cells isolated from 1-, 2-, 3- and 4-cm stylar lengths migrated to the negative pole, with the Sua displaying significantly
greater electrophoretic mobility than the Svn, reflecting a more positively charged cell surface on the Sua. The sperm cells
isolated from 1-cm style are very sensitive to electron potential in an electrophoretic field, presumably reflecting that
they are still in a young state. Differences in cell surface charge between the Sua and Svn may be related with cell fate
during fertilization.
Supported by National Natural Science Foundation of CHINA (30170060) 相似文献
33.
Amin A Benavides LC Holmes JP Gates JD Carmichael MG Hueman MT Mittendorf EA Storrer CE Jama YH Craig D Stojadinovic A Ponniah S Peoples GE 《Cancer immunology, immunotherapy : CII》2008,57(12):1817-1825
Background E75, a HER2/neu immunogenic peptide, is expressed in breast cancer (BCa). We have performed clinical trials of E75 + GM-CSF vaccine in disease-free,
node-positive and node-negative BCa patients at high recurrence risk and recurrences were noted in both control and vaccine
groups.
Methods Among the 186 BCa patients enrolled, 177 completed the study. Patients were HLA typed; the HLA-A2+/A3+ patients were vaccinated; HLA-A2−/A3− patients were followed as controls. Standard clinicopathological factors, immunologic response to the vaccine, and recurrences
were collected and assessed.
Results The control group recurrence rate was 14.8 and 8.3% in the vaccinated group (P = 0.17). Comparing the 8 vaccinated recurrences (V-R) to the 88 vaccinated nonrecurrent patients (V-NR), the V-R group had
higher nodal stage (≥N2: 75 vs. 5%, P = 0.0001) and higher grade tumors (%grade 3: 88 vs. 31%, P = 0.003). The V-R group did not fail to respond immunologically as noted by equivalent dimer responses and post-DTH responses.
Compared to control recurrent patients (C-R), V-R patients trended toward higher-grade tumors and hormone-receptor negativity.
C-R patients had 50% bone-only recurrences, compared to V-R patients with no bone-only recurrences (P = 0.05). Lastly, V-R mortality rate was 12.5% compared with 41.7% for the C-R group (P = 0.3).
Conclusions The vaccinated patients who recurred had more aggressive disease compared to V-NR patients. V-R patients had no difference
in immune response to the vaccine either in vitro or in vivo. V-R patients, when compared to C-R patients, trended towards
more aggressive disease, decreased recurrence rates, decreased mortality, and no bone-only recurrences.
Supported by the United States Military Cancer Institute and the Department of Clinical Investigation at Walter Reed Army
Medical Center. Funded primarily by the Clinical Breast Care Project. The opinions or assertions contained herein are the
private views of the authors and are not to be construed as official or reflecting the views of the Department of the Army,
the Department of the Navy, or the Department of Defense. This work represents original research that has not been submitted
elsewhere for publication. 相似文献
34.
Harry JGM Crijns Lori D Bash Fran?ois Chazelle Jean-Yves Le Heuzey Thorsten Lewalter Gregory YH Lip Aldo P Maggioni Alfonso Martín Piotr Ponikowski M?rten Rosenqvist Prashanthan Sanders Mauricio Scanavacca Alexandra A Bernhardt Sreevalsa Unniachan Hemant M Phatak Anselm K Gitt 《BMC cardiovascular disorders》2012,12(1):1-13
Background
Cigarette exposure increases brain oxidative stress. The literature showed that increased brain oxidative stress affects cardiovascular regulation. However, no previous study investigated the involvement of brain oxidative stress in animals exposed to cigarette and its relationship with cardiovascular regulation. We aimed to evaluate the effects of central catalase inhibition on baroreflex and cardiovascular responses in rats exposed to sidestream cigarette smoke (SSCS).Methods
We evaluated males Wistar rats (320-370 g), which were implanted with a stainless steel guide cannula into the fourth cerebral ventricle (4th V). Femoral artery and vein were cannulated for mean arterial pressure (MAP) and heart rate (HR) measurement and drug infusion, respectively. Rats were exposed to SSCS during three weeks, 180 minutes, 5 days/week (CO: 100-300 ppm). Baroreflex was tested with a pressor dose of phenylephrine (PHE, 8 ??g/kg, bolus) to induce bradycardic reflex and a depressor dose of sodium nitroprusside (SNP, 50 ??g/kg, bolus) to induce tachycardic reflex. Cardiovascular responses were evaluated before, 5, 15, 30 and 60 minutes after 3-amino-1,2,4-triazole (ATZ, catalase inhibitor, 0.001 g/100 ??L) injection into the 4th V.Results
Central catalase inhibition increased basal HR in the control group during the first 5 minutes. SSCS exposure increased basal HR and attenuated bradycardic peak during the first 15 minutes.Conclusion
We suggest that SSCS exposure affects cardiovascular regulation through its influence on catalase activity. 相似文献35.
Jonathan WF Mant Suzanne H Richards FD Richard Hobbs David Fitzmaurice Gregory YH Lip Ellen Murray Miriam Banting Kate Fletcher Joy Rahman Teresa Allan James Raftery Stirling Bryan 《BMC cardiovascular disorders》2003,3(1):1-10
Background
Statins effectively lower blood cholesterol and the risk of cardiovascular death. Immunomodulatory actions, independent of their lipid-lowering effect, have also been ascribed to these compounds. Since macrophages participate in several vascular pathologies, we examined the effect of statin treatment on the survival and differentiation of primary human monocytes.Methods
Peripheral blood mononuclear cells (PBMCs) from healthy individuals were cultured in the presence or absence of mevastatin. Apoptosis was monitored by annexin V / PI staining and flow cytometry. In parallel experiments, cultures were stimulated with LPS in the presence or absence of mevastatin and the release of IL-1β and IL-1Ra was measured by ELISA.Results
Among PBMCs, mevastatin-treated monocytes were particularly susceptible to apoptosis, which occurred at doses >1 microM and was already maximal at 5 microM. However, even at the highest mevastatin dose used (10 microM), apoptosis occurred only after 24 h of culture, possibly reflecting a requirement for cell commitment to differentiation. After 72 h of treatment the vast majority (>50%) of monocytes were undergoing apoptosis. Stimulation with LPS revealed that mevastatin-treated monocytes retained the high IL-1β output characteristic of undifferentiated cells; conversely, IL-1Ra release was inhibited. Concurrent treatment with mevalonolactone prevented the induction of apoptosis and suppressed both IL-1β and IL-1Ra release in response to LPS, suggesting a rate-limiting role for HMG-CoA reductase in monocyte differentiation.Conclusions
Our findings indicate that statins arrest the functional differentiation of monocytes into macrophages and steer these cells into apoptosis, suggesting a novel mechanism for the vasculoprotective properties of HMG-CoA reductase inhibitors. 相似文献36.
Kate Jolly Gregory YH Lip Josie Sandercock Sheila M Greenfield James P Raftery Jonathan Mant Rod Taylor Deirdre Lane Kaeng Wai Lee AJ Stevens 《BMC cardiovascular disorders》2003,3(1):1-11
Background
Cardiac rehabilitation following myocardial infarction reduces subsequent mortality, but uptake and adherence to rehabilitation programmes remains poor, particularly among women, the elderly and ethnic minority groups. Evidence of the effectiveness of home-based cardiac rehabilitation remains limited. This trial evaluates the effectiveness and cost-effectiveness of home-based compared to hospital-based cardiac rehabilitation.Methods/design
A pragmatic randomised controlled trial of home-based compared with hospital-based cardiac rehabilitation in four hospitals serving a multi-ethnic inner city population in the United Kingdom was designed. The home programme is nurse-facilitated, manual-based using the Heart Manual. The hospital programmes offer comprehensive cardiac rehabilitation in an out-patient setting.Patients
We will randomise 650 adult, English or Punjabi-speaking patients of low-medium risk following myocardial infarction, coronary angioplasty or coronary artery bypass graft who have been referred for cardiac rehabilitation.Main outcome measures
Serum cholesterol, smoking cessation, blood pressure, Hospital Anxiety and Depression Score, distance walked on Shuttle walk-test measured at 6, 12 and 24 months. Adherence to the programmes will be estimated using patient self-reports of activity. In-depth interviews with non-attendees and non-adherers will ascertain patient views and the acceptability of the programmes and provide insights about non-attendance and aims to generate a theory of attendance at cardiac rehabilitation. The economic analysis will measure National Health Service costs using resource inputs. Patient costs will be established from the qualitative research, in particular how they affect adherence.Discussion
More data are needed on the role of home-based versus hospital-based cardiac rehabilitation for patients following myocardial infarction and revascularisation, which would be provided by the Birmingham Rehabilitation Uptake Maximisation Study (BRUM) study and has implications for the clinical management of these patients. A novel feature of this study is the inclusion of non-English Punjabi speakers. 相似文献37.
Petra Liskova Lubica Dudakova Cerys J. Evans Karla E. Rojas Lopez Nikolas Pontikos Dimitra Athanasiou Hodan Jama Josef Sach Pavlina Skalicka Viktor Stranecky Stanislav Kmoch Caroline Thaung Martin Filipec Michael E. Cheetham Alice E. Davidson Stephen J. Tuft Alison J. Hardcastle 《American journal of human genetics》2018,102(3):447-459
38.
Centrosomes are the main microtubule‐organizing centers of animal cells. Although centrosome aberrations are common in tumors, their consequences remain subject to debate. Here, we studied the impact of structural centrosome aberrations, induced by deregulated expression of ninein‐like protein (NLP), on epithelial spheres grown in Matrigel matrices. We demonstrate that NLP‐induced structural centrosome aberrations trigger the escape (“budding”) of living cells from epithelia. Remarkably, all cells disseminating into the matrix were undergoing mitosis. This invasive behavior reflects a novel mechanism that depends on the acquisition of two distinct properties. First, NLP‐induced centrosome aberrations trigger a re‐organization of the cytoskeleton, which stabilizes microtubules and weakens E‐cadherin junctions during mitosis. Second, atomic force microscopy reveals that cells harboring these centrosome aberrations display increased stiffness. As a consequence, mitotic cells are pushed out of mosaic epithelia, particularly if they lack centrosome aberrations. We conclude that centrosome aberrations can trigger cell dissemination through a novel, non‐cell‐autonomous mechanism, raising the prospect that centrosome aberrations contribute to the dissemination of metastatic cells harboring normal centrosomes. 相似文献
39.
Sterigmatocystin (STG) is a toxic metabolite produced by severalAspergillus species. Because of its toxic and carcinogenic properties the occurrence of STG in food is considered to represent a potential
hazard to man. The present study was designed to investigate following points:
相似文献
1 | A survey of STG incidence in Ras cheese on local markets. Ras cheese samples were collected from Cairo, Giza and Kalubia governorates. Thirty five percent of the samples contained the toxin with a mean value of 22.23 μg /kg |
2 | Fate of STG contaminating milk during Ras cheese processing. Milk was artificially contaminated with 125 μg/kg and processed into Ras cheese. Eighty percent of the toxin was distributed into the curd and 20% into the whey. Cheese ripening effected toxin content and the effect was temperature dependent. At 6°C: toxin concentration was slightly affected; at 20°C the toxin was reduced by 16% after 90 days when low toxin concentration was used. |
3 | Formation of STG byA versicolor mold on Ras cheese. Ras cheese blocks were contaminated with spores of the mold. Toxin production started after 45 days of ripening and reached a maximum at 90 days and then declined. Cow’s milk favoured toxin production over buffaloe’s. Aged cheese inhibited toxin production. |