Longest Time (longest + time)

Distribution by Scientific Domains


Selected Abstracts


Cerebellar granule cells show age-dependent migratory differences in vitro

DEVELOPMENTAL NEUROBIOLOGY, Issue 2 2005
Krisztián Tárnok
Abstract Developmental differences between cerebellar granule cells during their migratory period were revealed using dissociated granule cell cultures isolated from 4, 7, or 10 days old (P4, P7, P10) mice. Under all culture conditions, the great majority of cultivated cell populations consisted of those granule cells that had not reach their final destination in the internal granule cell layer (IGL) by the age of isolation. In vitro morphological development and the expression of migratory markers (TAG-1, astrotactin, or EphB2) showed similar characteristics between the cultures. The migration of 1008 granule cells isolated from P4, P7, and P10 cerebella and cultivated under identical conditions were analyzed using statistical methods. In vitro time-lapse videomicroscopy revealed that P4 cells possessed the fastest migratory speed while P10 granule cells retained their migratory activity for the longest time in culture. Cultures obtained from younger postnatal ages showed more random migratory trajectories than P10 cultures. Our observations indicate that despite similar morphological and molecular properties, migratory differences exist in granule cell cultures isolated from different postnatal ages. Therefore, the age of investigation can substantially influence experimental results on the regulation of cell migration. © 2005 Wiley Periodicals, Inc. J Neurobiol, 2005 [source]


Coastal conglomerates around the Hadjer el Khamis inselbergs (western Chad, central Africa): new evidence for Lake Mega-Chad episodes

EARTH SURFACE PROCESSES AND LANDFORMS, Issue 10 2003
Mathieu Schuster
Abstract This paper reports on a study dealing with the rhyolitic inselbergs of Hadjer el Khamis that formed palaeoislands during Lake Mega-Chad events. Field observations have shown that: (1) conglomeratic patches of immature to mature clasts are preserved at the feet of the Hadjer el Khamis inselbergs; (2) in cross-section, their pro,le reveals a well de,ned cliff,platform junction at a constant elevation (325 m). The monolithological clasts show all degrees of roundness, from angular cobbles to well rounded pebbles. This wide range of maturity suggests a coastal origin for these cobbles. The system was permanently fed with angular clasts, which were progressively worn by waves. Cobbles that were wave-worked for the longest time are the best rounded. The cliff,platform junction is the result of erosion by waves, which attacked and undercut the inselberg cliffs during Lake Mega-Chad events. Asymmetrical erosion pro,les moreover suggest a wind regime dominated by SW to NE oriented winds. These interpretations have two implications. The elevation of the cliff,platform junction is an indication of the highest water level of Lake Mega-Chad at 320,325 m, which is in agreement with other observations elsewhere in the basin. The SW to NE oriented winds show that monsoon-related winds were prevalent during Lake Mega-Chad events, suggesting the Inter-Tropical Convergence Zone was located higher in latitude than today. Copyright © 2003 John Wiley & Sons, Ltd. [source]


Resistance of kale varieties to attack by Mamestra brassicae

AGRICULTURAL AND FOREST ENTOMOLOGY, Issue 2 2009
María E. Cartea
Abstract 1,The objectives of this work were to study the resistance of six kale (Brassica oleracea acephala group) varieties to cabbage moth Mamestra brassicae (L.) expressed as antibiosis and to determine the effect of plant age on larval survival and development. 2,The influence of plant age on resistance was determined using leaves from seedlings and from mature plants. Survival and development of M. brassicae larvae and feeding rates were determined in laboratory bioassays. 3,Leaves from seedlings were more suitable than those of mature plants for establishing differences in resistance. There were significant differences between kale varieties in larval survival, growth rate, leaf feeding, and time to pupation but not pupal weight. The varieties MBG-BRS0031, MBG-BRS0351, and MBG-BRS0287 reduced survival of M. brassicae larvae. Larvae that fed on MBG-BRS0060 were the heaviest and took the longest time to pupation. MBG-BRS0031 was consumed significantly less by larvae than were all the other varieties examined. Leaves from mature plants of MBG-BRS0142 and MBG-BRS0170 were defoliated significantly less than those of other varieties. 4,In conclusion, the variety MBG-BRS0031 may be a promising source of resistance to M. brassicae. Leaf antibiotic resistance was shown to play a role in defense against M. brassicae attack but it is not the only possible mechanism of resistance. [source]


Locally advanced prostate cancer,biochemical results from a prospective phase II study of intermittent androgen suppression for men with evidence of prostate-specific antigen recurrence after radiotherapy

CANCER, Issue 5 2007
Nicholas Bruchovsky MD
Abstract BACKGROUND. Biochemical results from a prospective Phase II trial of intermittent androgen suppression for recurrent prostate cancer after radiotherapy were analyzed for correlations to the onset of hormone-refractory disease. METHODS. Patients with histologically confirmed adenocarcinoma of the prostate and a rising serum prostate-specific antigen (PSA) level after external beam irradiation of the prostate were treated intermittently with a 36-week course of cyproterone acetate and leuprolide acetate. Then, patients were stratified according to their serum PSA range at the start of each cycle and were followed with further biochemical testing until disease progression was evident. RESULTS. The mean PSA reduction was 95.2% irrespective of stratification group. A baseline serum PSA level <10 ,g/L and a serum PSA nadir ,0.2 ,g/L were associated with the longest time off treatment. The overall mean nadir PSA value in the progression group at 1.40 ± 0.19 ,g/L was 2.6-fold greater than the value of 0.55 ± 0.88 ,g/L in the no-progression group (P = .0002). Recovery of serum testosterone to a level of ,7.5 nmol/L was observed in 75%, 50%, 40%, and 30% of men in Cycles 1 to 4, respectively, and was sufficient to normalize the level of hemoglobin in each cycle, which dropped by an average of 10.8 g/L during treatment (P < .0001). CONCLUSIONS. The length of the off-treatment interval during cyclic androgen withdrawal therapy was related inversely to baseline and nadir levels of serum PSA. Nadir PSA was a powerful predictor of early progression to androgen independence. Cancer 2007 © 2007 American Cancer Society. [source]