Heart rate (HR) is controlled solely by via cardiac parasympathetic outflow in tetraplegic individuals, who lack supraspinal control of sympathetic outflows and circulating catecholamines but have intact vagal pathways. A high-frequency component (HF; at 0.15-0.40 Hz) of the power spectrum of HR variability and its relative value against total power (HF/Total) were assessed using a wavelet transform to identify cardiac parasympathetic outflow. The relative contribution of cardiac parasympathetic and sympathetic outflows to controlling HR was estimated by comparing the HF/Total-HR relationship between age-matched tetraplegic and normal men. Six tetraplegic men with complete cervical spinal cord injury performed static arm exercise at 35% of the maximal voluntary contraction until exhaustion. Although resting cardiac output and arterial blood pressure were lower in tetraplegic than normal subjects, HR, HF, and HF/Total were not statistically different between the two groups. When tetraplegic subjects developed the same force during exercise as normal subjects, HF and HF/Total decreased to 67-90% of the preexercise control and gradually recovered 1.5 min after exercise. The amount and time course of the changes in HF/Total during and after exercise coincided well between both groups. In contrast, the increase in HR at the start of exercise was blunted in tetraplegic compared with normal subjects, and the HR recovery following exercise was also delayed. It is likely that, although the withdrawal response of cardiac parasympathetic outflow is preserved in tetraplegic subjects, sympathetic decentralization impairs the rapid acceleration of HR at the onset of exercise and the rapid deceleration following exercise. 相似文献
Spin trapping of peroxy and alkoxy radicals generated from the hydroperoxide of methyl linoleate was studied using methyl-N-duryl nitrone (MDN) and phenyl-N-tert-butyl nitrone (PBN) as spin traps. The conjugated dienyl carbon radical was also generated from methyl linoleate and spin-trapped. The spin adducts of peroxy, alkoxy, and dienyl carbon radicals were observed by ESR and their hyperfine splitting constants were determined. The spin adducts of peroxy and alkoxy radicals could be distinguished clearly with MDN. 相似文献
The development of a radioimmunoassay (RIA) for the beta 2-stimulant formoterol is described. The sensitivity of the method is 0.1 ng/ml in plasma and urine, when a 1-ml sample is used. The cross-reactivity of the antiserum with formoterol glucuronide was 30%. Since formoterol is metabolized extensively to formoterol glucuronide in rats, dogs and humans, extraction with ethyl ether prior to the radioimmunoassay was carried out. Satisfactory agreement was obtained for levels of formoterol in plasma and urine when they were determined by RIA and gas chromatography-mass spectrometry. The concentration of formoterol was determined in dog plasma and human urine after oral administration of formoterol fumarate to dogs (61 mcg/kg) and humans (40 mcg). 相似文献
The intracellular concentrations of the polypeptides encoded by the two enolase (ENO1 and ENO2) and three glyceraldehyde-3-phosphate dehydrogenase (TDH1, TDH2, and TDH3) genes were coordinately reduced more than 20-fold in a Saccharomyces cerevisiae strain carrying the gcr1-1 mutation. The steady-state concentration of glyceraldehyde-3-phosphate dehydrogenase mRNA was shown to be approximately 50-fold reduced in the mutant strain. Overexpression of enolase and glyceraldehyde-3-phosphate dehydrogenase in strains carrying multiple copies of either ENO1 or TDH3 was reduced more than 50-fold in strains carrying the gcr1-1 mutation. These results demonstrated that the GCR1 gene encodes a trans-acting factor which is required for efficient and coordinate expression of these glycolytic gene families. The GCR1 gene and the gcr1-1 mutant allele were cloned and sequenced. GCR1 encodes a predicted 844-amino-acid polypeptide; the gcr1-1 allele contains a 1-base-pair insertion mutation at codon 304. A null mutant carrying a deletion of 90% of the GCR1 coding sequence and a URA3 gene insertion was constructed by gene replacement. The phenotype of a strain carrying this null mutation was identical to that of the gcr1-1 mutant strain. 相似文献
A bioreactor with a column of flocculated cells of the moderate halophile Micrococcus varians subsp. halophilus which adsorbed the halophilic nuclease H was designed to be used in the production of 5′ nucleotides from RNA. A remarkable characteristic of the flocculated cells was that they preferentially adsorbed much exogenous nuclease, excluding adsorbed 5′ nucleotidase. Furthermore, desalting treatment of the flocculated cells in the presence of 2% MgSO4 · 7H2O gave rise to selective inactivation of 5′ nucleotidase without the loss of nuclease H activity, and 5′-guanylic acid was produced with the bioreactor. 相似文献
The dependence of vegetative propagation on the production of individual plants was examined inDisporum smilacinum A. Gray on the basis of shading experiments and field surveys. This species typically showed four types of reproductive behavior:
sterile plants producing one plantlet (no propagation), sterile plants producing more than two plantlets (vegetative propagation),
fertile plants producing one plantlet (sexual reproduction) and fertile plants producing more than two plantlets (both sexual
reproduction and vegetative propagation).
The propagation ofD. smilacinum was clearly related to the annual net production of each individual plant. The probability of a mother plant producing more
than two vegetative propagules (plantlets) increased with net production of the plant in the current year. The number of propagules
per plant and runner length increased with net production.
It was possible to explain the types of reproductive behavior of this species on the basis of both the initial plant size
before sprouting and its net production during the growing season. There was a critical initial plant size for sexual reproduction
and a critical level of production for vegetative propagation. 相似文献
The distribution of anthocyanins in spring sprouted and/or autumn coloured leaves of Dipteronia sinensis and Acer (119 taxa) was studied.
Dipteronia contained four cyanidin glycosides: the 3-glucoside, 3-rutinoside, 3-galloylglucoside and 3,5-diglucoside. Acer contained five cyanidin glycosides: 3-glucoside, 3-rutinoside, 3-galloylglucoside, 3-galloylrutinoside and 3,5-diglucoside, two delphinidin glucosides: 3-glucoside and 3-rutinoside and three unidentified anthocyanins. Both Dipteronia and Acer contained the recently reported cyanidin 3-galloylglucoside. The anthocyanin constituents in spring leaves were more complex than those found in autumn coloured leaves: nine in spring and six in autumn. The presence/absence of the major anthocyanins in the spring sprouted leaves of 111 Acer taxa analysed were grouped into 17 distribution patterns. In the autumn the number of anthocyanin distribution patterns was found to be 11. In Acer, cyanidin glycosides were found in 20 sections and delphinidin glycosides in 17 out of the 21 sections analysed. Although the distribution of anthocyanins showed no clear relations among sections, delphinidin glycosides were mainly found in sections Macrantha, Goniocarpa and Saccharina. There were no differences in the pigment constituents in the species native to different countries, such as A. rubrum in North America and A. pycnanthum in Japan, both containing the same pigments: cyanidin 3-glucoside, 3-rutinoside, 3-galloylglucoside, 3-galloylrutinoside and 3,5-diglucoside. 相似文献
The expression of class II major histocompatibility complex (MHC) antigens on alveolar epithelial cells and macrophages was
investigated immunocytochemically in paraquat-induced alveolitis in the rat lung. Until 2 days after paraquat injection, class
II MHC antigens were expressed on the type II alveolar epithelium without any inflammatory cellular infiltration. From the
4th to the 7th day after paraquat injection, class II MHC antigen-positive macrophages increased in the alveolar spaces, whereas
the expression on the type II alveolar epithelium became obscure. Over 10 days after the injection, interstitial fibrosis
progressed and the intra-alveolar inflammatory infiltrates decreased. Epithelial cells lining the thickened fibrous septa
no longer expressed class II MHC antigens. These results suggest that chemical stimuli can induce class II MHC antigen expression
on the type II alveolar epithelium in the early stage of cellular injury, followed by inflammatory infiltration and interstitial
fibrosis. 相似文献
A technique for the rapid and accurate estimation of nonheme iron using inductively coupled plasma-atomic emission spectrometry is described. Yttrium was used as an internal standard. An external calibration method was used. The standards were prepared in a matrix composed of 2.5N HCl in 10% (w/v) trichloroacetic acid. The supernatant and coagulum fractions of liver nonheme iron were separated by the method of Drysdale and Ramsay with minor modification. The data determined by this procedure was compared and found to be agreement with data determined by the method of Hallgren. To evaluate the iron status of rats, hemoglobin and liver nonheme iron were determined. Hemoglobin and all of the nonheme iron fractions of the rats fed an iron-deficient diet were significantly lower than those of the rats fed an iron-sufficient diet. The blood content in the liver was estimated to be 80 microL/g from the blood iron concentration, and the difference between total and nonheme iron concentration in liver. 相似文献