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71.
The respiratory sensation and some routine cardiorespiratory parameters were studied on native Highlanders from the Argentine
Andes and on Lowlanders from Europe, already tested during previous high altitude expeditions. The tests were performed at
various altitude levels from 2688m e.i., the village altitude for Highlanders, to 5600m during an expedition to Mt. Aconcagua
(6990m). At rest, the perception of 4 external inspiratory resistive loads (ranged between 2.5 and 13 cm.H2O.L-1.s) can allow
us to fix by discrimination the sensitivity index P(A) independently of response bias (B) according to Sensory Decision Theory
(SDT). The Andean highlanders did not experience the respiratory sensation at the same limits as the European lowlanders well
adaptated to high altitude. At higher altitudes than their village altitude, their respiratory sensation presented a lower
threshold of perception and a weaker discrimination which might be partly explained by the evolution of some parameters of
their cardio-respiratory function when altitude increased. Indeed, in response to high altitude hypoxia (5600m), they increased
their respiratory frequency and not their minuteventilation or mouth pressure. This chosen ventilatory pattern was opposite
to the one chosen by the Lowlanders and did not allow for sufficient adaptation to a more important altitude hypoxia than
that of their village altitude. In conclusion, the Andean highlanders wellbeing adapted to their village altitude, exhibited
a difficult acclimatization to higher altitudes which might be due to the characteristics of their respiratory sensation.
These results might explain their weak physical performances during ascent to the Mt. Aconcagua summit in spite of special
training. 相似文献
72.
Variant forms of a group I intron in nuclear small-subunit rRNA genes of the marine red alga Porphyra spiralis var. amplifolia 总被引:3,自引:0,他引:3
A group IC1 intron occurs in nuclear small-subunit (18S) ribosomal RNA (SSU
rRNA) genes of the marine red alga Porphyra spiralis var. amplifolia. This
intron occurs at the same position as the self- splicing group IC1 introns
in nuclear SSU rDNAs of the fungus Pneumocystis carinii and in the green
alga Chlorella ellipsoidea and shares sequence identity with the
Pneumocystis carinii intron in domains L1, P1, P2, and L2, outside the
conserved core. Three size variants, differing in amount of sequence in L1,
exist and are differentially distributed in geographically distinct
populations. Preliminary data suggest that the largest variant can
self-splice in vitro. Short open reading frames are present but do not
correspond to known genes. Repeated nucleotide motifs, reminiscent of
duplicated target sites of transposons or Alu elements, are associated with
the intron and with one of the variant forms of L1. Insertions are present
in nuclear SSU rDNAs of several other Porphyra species and of the red alga
Bangia atropurpurea; insertionless rDNA variants also occur in several
Porphyra species. Our observations are most readily explained by intron
mobility, although it remains unclear how transfer could have been mediated
between genomes of organisms as ecologically diverse as marine red algae,
freshwater green algae, and a mammalian-pathogenic fungus.
相似文献
73.
Lynn Willert H.; Meyer Elizabeth A.; Peppiatt Cecil E.; Derby Charles D. 《Chemical senses》1994,19(4):331-347
We used spiny lobsters (Panulirus argus) in a discriminationlearning procedure with aversive conditioning to examine theirbehavioral discrimination of adenosine-5'-monophosphate (AMP),betaine, L-cysteine and their binary mixtures. Our results showthat spiny lobsters can clearly discriminate among binary mixturesand their components. Lobsters aversively conditioned to avoidresponding to a binary mixture continued to respond to thatmixture's components, and lobsters that were aversively conditionedto avoid responding to a compound tended to continue to respondto binary mixtures containing that compound. Thus, responsesof conditioned lobsters to binary mixtures were not usuallyintermediate between the responses to the mixtures' components,which might be expected for response-matched compounds. Thisresult might arise from any of several factors. First, it mightresult from mixture interactions in the peripheral olfactorysystem, if the responses of olfactory receptor neurons to onecomponent of a binary mixture were suppressed by the other component,making the response to the mixture more similar to the suppressingcomponent. Electrophysiological data from a population of 50singly-recorded olfactory receptor neurons (Daniel and Derby,1994) do not consistently support this idea. A second possiblereason for the behavioral response to a binary mixture not beingintermediate between the responses to its components involveshigher order processing, such as mixture interactions generatedin olfactory interneurons in the CNS (which is known to occur:Derby et al., 1985; Ache, 1989), configural learning or associativeprocessing. 相似文献
74.
Pascal Steullet C. D. Derby 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1997,180(2):123-135
The aim of this study was to investigate quality coding of blend ratios of binary mixtures by olfactory receptor cells in
the spiny lobster. Three odorants (adenosine-5′-monophosphate, l-glutamate, and taurine) at 0.1–100 μmol · l−1 and seven blend ratios of each of their binary mixtures at a total concentration of 100 μmol · l−1 were used. The olfactory cells recorded (n = 48) evoked across-neuron patterns for single odorants that were well separated from each other. Across-neuron patterns
varied with stimulus concentration but less than with stimulus type. Blend ratios of the three mixtures evoked across-neuron
patterns that were orderly placed within a continuum between those elicited by the components. Mixture interactions, defined
as a lack of independent effects by a mixture's components, occurred in 25, 24 and 37% of responses to blend ratios of glutamate/taurine,
adenosine-5′-monophosphate/taurine, and glutamate/adenosine-5′-monophosphate, respectively. These mixture interactions did
not have a large enough effect on the across-neuron patterns for the mixtures such they would be novel relative to those of
the single components. These results suggest that despite mixture interactions the quality of individual compounds is not
lost when mixed. This corroborates behavioral studies showing that spiny lobsters have the ability to elementally process
odor mixtures.
Accepted: 23 August 1996 相似文献
75.
76.
77.
Ferry Cornelissen Adriana MC Mus Patrick S Asmawidjaja Jan Piet van Hamburg Joel Tocker Erik Lubberts 《Arthritis research & therapy》2009,11(6):1-13
Introduction
A protein analysis using a mass spectrometry indicated that there are serum proteins showing significant quantitative changes after the administration of infliximab. Among them, connective tissue growth factor (CTGF) seems to be related to the pathogenesis of rheumatoid arthritis (RA). Therefore, this study was conducted to investigate how CTGF is associated with the disease progression of RA.Methods
Serum samples were collected from RA patients in active or inactive disease stages, and before or after treatments with infliximab. CTGF production was evaluated by ELISA, RT-PCR, indirect immunofluorescence microscopy, and immunoblotting. Osteoclastogenesis was evaluated using tartrate-resistant acid phosphatase (TRAP) staining, a bone resorption assay and osteoclasts specific catalytic enzymes productions.Results
The serum concentrations of CTGF in RA were greater than in normal healthy controls and disease controls. Interestingly, those were significantly higher in active RA patients compared to inactive RA patients. Furthermore, the CTGF levels significantly were decreased by infliximab concomitant with the disease amelioration. In addition, tumour necrosis factor (TNF)α can induce the CTGF production from synovial fibroblasts even though TNFα can oppositely inhibit the production of CTGF from chondrocytes. CTGF promoted the induction of the quantitative and qualitative activities of osteoclasts in combination with M-CSF and receptor activator of NF-κB ligand (RANKL). In addition, we newly found integrin αVβ3 on the osteoclasts as a CTGF receptor.Conclusions
These results indicate that aberrant CTGF production induced by TNFα plays a central role for the abnormal osteoclastic activation in RA patients. Restoration of aberrant CTGF production may contribute to the inhibition of articular destruction in infliximab treatment. 相似文献78.
79.
Abstract: The family Phylloporinidae was introduced in the late 19th century to accommodate a small number of Palaeozoic bryozoan genera characterized by irregularly fenestrated colonies generated by anastomosis of unilaminate branches. Among the first named of these genera were Chasmatopora Eichwald, 1855 and Phylloporina Ulrich in Foerste, 1887. The two names have been variously in fashion, and there has been confusion about whether they are subjective synonyms or are distinct genera. This taxonomic confusion has been due in large part to whether the single species (Retepora angulata Hall, 1847) assigned to Phylloporina in Foerste (1887) or the species that Ulrich intended (Retepora trentonensis Nicholson, 1875) is the type species and also because of lack of sufficient information about Foerste’s material to characterize it well. We here redescribe the pertinent species, erect the new species Chasmatopora foerstei for the species that Foerste incorrectly assigned to Phylloporina angulata (Hall), and suggest that Retepora trentonensis Nicholson be retained as type species of Phylloporina based on prevailing usage, until the issue is settled by the International Commission on Zoological Nomenclature. 相似文献
80.