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41.
c-Fos expression in the midbrain periaqueductal gray after chemoreceptor and baroreceptor activation
Hayward LF Von Reitzenstein M 《American journal of physiology. Heart and circulatory physiology》2002,283(5):H1975-H1984
The pattern of Fos-like immunoreactivity (FLI) in the periaqueductal gray (PAG) associated with activation of arterial chemoreceptors versus baroreceptor afferents was examined in urethane-anesthetized rats. Chemoreflex responses elicited by repeat intravenous injections of potassium cyanide (KCN; 90 microg/kg) significantly increased FLI in all columns of the PAG relative to saline-injected animals. Pressor responses elicited by intravenous phenylephrine (PE) produced a similar pattern of increased FLI throughout the PAG except in the dorsomedial and lateral columns of the caudal PAG, where FLI was minimal. Chemoreflex responses were unaltered by blockade of excitatory amino acid receptors in the dorsomedial PAG, and < 10% of the neurons of the caudal PAG that expressed FLI after KCN stimulation were retrogradely labeled from the A5 region of the caudal ventrolateral pons. These results indicate that integration of chemoreceptor inputs occurs primarily in the dorsal and lateral columns of the caudal PAG, but these neurons have little direct descending influence over lower brain stem regions integral to the central arterial chemoreflex arc. 相似文献
42.
43.
Maria V. Croce Marcela Fejes Norma Riera D. A. Minoldo Amada Segal-Eiras 《Cancer immunology, immunotherapy : CII》1985,20(1):91-95
Summary A total of 122 sera from acute lymphoblastic leukemia (ALL) patients were analyzed for circulating immune complexes (CIC) by two methods: the 125I-C1q binding assay and the polyethylene glycol precipitation test (PEG). The results were correlated with induction, remission and relapse stages of the disease. Using the first method the levels of CIC in induction were 15.18±9.15, with 19/29 positive cases (65.50%), P<0.001 compared with controls. In the remission phase the levels were 9.02±5.62, 11/45 (24.49%) nonsignificant P value, and in relapse they were 16.14±11.17 28/48 (58.33%) P<0.001. The PEG precipitation test results were: 0.33±0.10, 8/22 (36.36%); 0.24±0.11, 10/48 (20.83%) and 0.28±0.10, 6/28 (21.42%), respectively. Thus the values of CIC as measured by PEG in the three clinical of phases ALL did not differ significantly from controls. This contrasts with results obtained by the radioiodinated C1q binding assay, where the incidence of positive values was significantly higher in induction and in relapse and lower in the remission phase. These observations were extended in sequential vertical studies performed in a group of patients. These results suggest that raised CIC detected by the 125I-C1q method may reflect a progressive state in ALL and that quantitation of these immune complexes may provide an adequate biochemical marker for prognosis. 相似文献
44.
Amir Malaki Nik Marcela Alexander Vaino Poysa Lorna Woodrow Milena Corredig 《Food biophysics》2011,6(1):26-36
The effect of soy protein subunit composition on the acid-induced aggregation of soymilk was investigated by preparing soymilk
from different soybean lines lacking specific glycinin and β-conglycinin subunits. Acid gelation was induced by glucono-δ-lactone
(GDL) and analysis was done using diffusing wave spectroscopy and rheology. Aggregation occurred near pH 5.8 and the increase
in radius corresponded to an increase in the elastic modulus measured by small deformation rheology. Diffusing wave spectroscopy
was also employed to follow acid gelation, and data indicated that particle interactions start to occur at a higher pH than
the pH of onset of gelation (corresponding to the start of the rapid increase in elastic modulus). The protein subunit composition
significantly affected the development of structure during acidification. The onset of aggregation occurred at a higher pH
for soymilk samples containing group IIb (the acidic subunit A3) of glycinin, than for samples prepared from Harovinton (a commercial variety containing all subunits) or from genotypes
null in glycinin. The gels made from lines containing group I (A1, A2) and group IIb (A3) of glycinin resulted in stiffer acid gels compared to the lines containing only β-conglycinin. These results confirmed that
the ratio of glycinin/β-conglycinin has a significant effect on gel structure, with an increase in glycinin causing an increase
in gel stiffness. The type of glycinin subunits also affected the aggregation behavior of soymilk. 相似文献
45.
Juraj Blasko Marcela Martoncikova Kamila Lievajova Kamila Saganova Andrea Korimova Eniko Racekova 《Central European Journal of Biology》2012,7(3):397-403
Increased proliferation activity in the central canal ependyma of adult rodent spinal cord was described after injury and
is thought to participate in recovery processes. Proliferation activity is scarce under physiological conditions, but still
could be of importance, as in vitro studies showed that the spinal cord ependyma is an internal source of neural stem cells. Data from these studies indicate
that there are regional differences in the distribution of proliferation activity along the rostro-caudal axis. We analyzed
the proliferation activities in the ependyma within the entire extent of intact adult rat spinal cord. To identify proliferating
cells we performed immunohistochemistry either for cell cycle S-phase marker BrdU or for the nuclear protein Ki-67. BrdU and
Ki-67 positive cells were counted on sections selected from four spinal cord regions — cervical, thoracic, lumbar and sacral/coccygeal.
Analysis showed that the number of BrdU positive cells within the ependyma was very low in all subdivisions of the spinal
cord. Both BrdU and Ki-67 labeling revealed a significantly higher number of proliferating cells in the ependyma of sacrococcygeal
part in comparison to all other spinal cord regions, suggesting that the caudal spinal cord might have potentially higher
regeneration capacity compared to more rostral parts. 相似文献
46.
David L. A. Gaveau Sean Sloan Elis Molidena Husna Yaen Doug Sheil Nicola K. Abram Marc Ancrenaz Robert Nasi Marcela Quinones Niels Wielaard Erik Meijaard 《PloS one》2014,9(7)
The native forests of Borneo have been impacted by selective logging, fire, and conversion to plantations at unprecedented scales since industrial-scale extractive industries began in the early 1970s. There is no island-wide documentation of forest clearance or logging since the 1970s. This creates an information gap for conservation planning, especially with regard to selectively logged forests that maintain high conservation potential. Analysing LANDSAT images, we estimate that 75.7% (558,060 km2) of Borneo''s area (737,188 km2) was forested around 1973. Based upon a forest cover map for 2010 derived using ALOS-PALSAR and visually reviewing LANDSAT images, we estimate that the 1973 forest area had declined by 168,493 km2 (30.2%) in 2010. The highest losses were recorded in Sabah and Kalimantan with 39.5% and 30.7% of their total forest area in 1973 becoming non-forest in 2010, and the lowest in Brunei and Sarawak (8.4%, and 23.1%). We estimate that the combined area planted in industrial oil palm and timber plantations in 2010 was 75,480 km2, representing 10% of Borneo. We mapped 271,819 km of primary logging roads that were created between 1973 and 2010. The greatest density of logging roads was found in Sarawak, at 0.89 km km−2, and the lowest density in Brunei, at 0.18 km km−2. Analyzing MODIS-based tree cover maps, we estimate that logging operated within 700 m of primary logging roads. Using this distance, we estimate that 266,257 km2 of 1973 forest cover has been logged. With 389,566 km2 (52.8%) of the island remaining forested, of which 209,649 km2 remains intact. There is still hope for biodiversity conservation in Borneo. Protecting logged forests from fire and conversion to plantations is an urgent priority for reducing rates of deforestation in Borneo. 相似文献
47.
48.
Gonzalo Castillo‐Campos Rosa Emilia Prez‐Prez Octavio Crdova‐Chvez Jos Guadalupe García‐Franco Marcela Eugenia da Silva Cceres 《Nordic Journal of Botany》2019,37(12)
In the tropics, corticolous lichen richness and cover tend to increase from the trunk base to the top of the crown of trees. In this study we calculated the total beta diversity of the lichen community along a vertical gradient on Quercus laurina in Mexican cloud forest. By comparing the richness and cover of the lichens by zone, we show that foliose and fruticose lichens are a minor component of the total lichen species richness, but have a higher cover than the crustose lichens. Five zones were identified along each phorophyte (n = 15) with a diameter at breast height >40 cm. A total of 92 species were identified. Of these, 38% were found only in a single zone, 51% were shared between the different zones and 11% occurred across all zones. Species richness and cover increased from the lowest to the highest zones of the phorophytes. Dissimilarity in species composition between the zones could be explained by species replacement. An indicator species analysis revealed that only a few species, e.g. Hypotrachyna vexans, H. cf. sublaevigata and Ramalina cf. sinaloensis prefer a particular zone. The results show that the lichen community associated with Quercus laurina phorophytes is highly diverse and suggest that species richness and cover are related to the zone and the various growth forms. 相似文献
49.
Marcela Simontacchi Carlos García-Mata Carlos G. Bartoli Guillermo E. Santa-María Lorenzo Lamattina 《Plant cell reports》2013,32(6):853-866
Nitric oxide (NO) is a small gaseous molecule, with a free radical nature that allows it to participate in a wide spectrum of biologically important reactions. NO is an endogenous product in plants, where different biosynthetic pathways have been proposed. First known in animals as a signaling molecule in cardiovascular and nervous systems, it has turned up to be an essential component for a wide variety of hormone-regulated processes in plants. Adaptation of plants to a changing environment involves a panoply of processes, which include the control of CO2 fixation and water loss through stomatal closure, rearrangements of root architecture as well as growth restriction. The regulation of these processes requires the concerted action of several phytohormones, as well as the participation of the ubiquitous molecule NO. This review analyzes the role of NO in relation to the signaling pathways involved in stomatal movement, plant growth and senescence, in the frame of its interaction with abscisic acid, auxins, gibberellins, and ethylene. 相似文献