共查询到20条相似文献,搜索用时 15 毫秒
1.
G Dautel 《Canadian Metallurgical Quarterly》1996,41(3):277-283
This study demonstrates a pH-dependent inhibition of Mg(2+)- and Ca(2+)-ATPase activities of Nostoc linckia and Chlorella vulgaris exposed to AlCl3, AlF3, NaF and AlCl3+NaF together. AlF3 and the combination of AlCl3+NaF were more inhibitory to both the enzymes as compared with AlCl3 and NaF. Toxicity of the test compounds increased with increasing acidity. Interaction of AlCl3+NaF was additive on N. linckia and C. vulgaris, respectively, at pH 7.5 and 6.8, and synergistic at pH 6.0 and 4.5. In the presence of 60 and 100 microM PO4(3-) an increased NaF concentration (in the AlCl3+NaF combination) was required to produce the same degree of inhibition in ATP synthesis and ATPase activity. Toxicity of fluoroaluminate was reduced in the presence of EDTA and citrate. Except for beryllium to some extent, combinations of cadmium, cobalt, iron, manganese, tin and zinc with fluoride were not as effective as aluminium in inhibiting the ATPase activity. The presence of a 100 kDa protein band in SDS-PAGE of both control as well as AlCl3+NaF-treated samples suggested that AlF4- inhibits the ATPase activity by acting as a functional barrier without affecting the structure of the enzyme. 相似文献
2.
RU Hasen?hrl O Jentjens MA De Souza Silva C Tomaz JP Huston 《Canadian Metallurgical Quarterly》1998,354(2-3):123-133
There is evidence that the neurokinin substance P plays a role in neural mechanisms governing learning and reinforcement. Reinforcing and memory-promoting effects of substance P were found after it was injected into several parts of the brain and intraperitoneally. With regard to the close link between anxiety and memory processes for negative reinforcement learning, the aim of the present study was to gauge the effect of substance P on anxiety-related behaviors in the rat elevated plus-maze and social interaction test. Substance P was tested at injection sites where the neurokinin has been shown to promote learning and to serve as a reinforcer, namely in the periphery (after i.p. administration) and after injection into the nucleus basalis magnocellularis region. When administered i.p., substance P had a biphasic dose-response effect on behavior in the plus-maze with an anxiolytic-like action at 50 microg/kg and an anxiogenic-like one at 500 microg/kg. After unilateral microinjection into the nucleus basalis magnocellularis region, substance P (1 ng) was found to exert anxiolytic-like effects, because substance P-treated rats spent more time on the open arms of the plus-maze and showed an increase in time spent in social interaction. Furthermore, the anxiolytic effects of intrabasalis substance P were sequence-specific since injection of a compound with the inverse amino acid sequence of substance P (0.1 to 100 ng) did not influence anxiety parameters. These results show that substance P has anxiolytic-like properties in addition to its known promnestic and reinforcing effects, supporting the hypothesis of a close relationship between anxiety, memory and reinforcement processes. 相似文献
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Acute experiments were conducted on cats under nembutal anesthesia. A study was made of the dynamics of the changes occurring in the curve of restoration of the test response amplitude in the thalamo-cortical fibers to the pared stimulation of the medial lemniscus with various actions on the somatosensory ared. The curve under study served as an indicator of the corticofugal influences on the inhibitory after process in the transmission nucleus of the thalamus. The influences on one somatosensory area of the cortex blocked the transmission of the afferent signals in 70% of the neurons of the transmission nucleus of the thalamus. A correlation between the number of the neurons participating in the reaction and the character of the initial phase of the inhibitory afterprocess was noted. 相似文献
4.
J Tomkins P Usher JY Slade PG Ince A Curtis K Bushby PJ Shaw 《Canadian Metallurgical Quarterly》1998,9(17):3967-3970
The abnormal assembly and accumulation of neurofilaments (NF) in the perikarya and proximal axons of motor neurones is a characteristic of ALS. Deletions in the KSP repeat region of the NF-H gene have previously been reported in seven patients with sporadic ALS. Here we report the identification of a novel 84 bp insertion in the NF-H gene. This leads to an extra four KSP repeat elements in a highly conserved repetitive region of the gene. Although neurofilament mutations are only associated with a very small proportion of ALS cases, this insertion provides further support of a role for neurofilaments in the pathogenesis of ALS. 相似文献
5.
The relationship between substance P-containing axons and sympathetic preganglionic neurons possessing the neurokinin-1 receptor was investigated in the lateral horn of the rat thoracic spinal cord. Sympathetic preganglionic neurons were labelled retrogradely with Fluorogold. Sections containing labelled cells were reacted with antibodies against choline acetyltransferase, substance P and the neurokinin-1 receptor and examined with three-colour confocal laser scanning microscopy. In all, 95 sympathetic preganglionic neurons were examined and 79% of these were immunoreactive for the neurokinin-1 receptor. Substance P-immunoreactive axons not only made contacts with preganglionic neurons which were immunoreactive for the receptor but also made contacts with cells which did not express the receptor. Dendrites, labelled with immunoreactivity for choline actyltransferase, also received contacts from substance P-immunoreactive varicosities but this was not related to the presence or the absence of receptor. An electron microscopic analysis was performed to investigate the relationship between substance P-containing boutons and dendrites possessing the neurokinin-1 receptor. Immunoreactivity for substance P was detected with peroxidase immunocytochemistry and immunoreactivity for the receptor was detected with the silver-intensified gold method. Substance P-containing boutons made synapses with dendrites which were positively and negatively labelled for the receptor. Receptor immunoreactivity was not usually present at synapses formed by substance P boutons with neurokinin-1-immunoreactive dendrites. It is concluded that substance P may modulate much of the activity of sympathetic preganglionic neurons through an indirect non-synaptic mechanism. 相似文献
6.
This paper reviews basic epidemiologic characteristics of 1549 changes located on face, neck and lips and surgically treated at the ORL Department of the General hospital in Subotica during the period 1981-1990. We analyzed the following parameters: frequency of certain diseases, their distribution according to the studied period of time, sex and age distribution, place of living, interaction between malignant and benign tumors as well as eventual influence of some meteorologic factors in regard to the previous 10-year period. It has been established that malignant tumors, precancerous and benign tumors make up 70% of surgically treated patients. There has been no statistically significant difference between sexes or according to the place of living. Most patients are in the eighth decade. It has been established that there is a slight trend of increase in regard to the number of operated patients in some studied years both in malignant and benign tumors, but there seems to be no connection between the number of surgically treated patients and analyzed meteorologic factors. 相似文献
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Necrotizing fasciitis (NF) is a rapidly progressive soft tissue infection with high morbidity and mortality rates. Its occurrence in the head and neck region is uncommon, the majority of reported cases being limited to involvement of the neck, usually from infections of dental or pharyngeal origin. Involvement of the face from NF is rare; only 35 such cases have been reported in the literature since 1960. It is not only associated with a high mortality but can also result in severe disfigurement of the face, posing challenging reconstructive problems. Successful management of facial NF requires early diagnosis, prompt institution of broad spectrum antibiotics, aggressive surgical debridement to control the infection, and reconstruction of the resultant soft tissue defects. This report describes four additional cases of facial necrotizing fasciitis. One of the four patients died as a result of sepsis and multi-organ system failure. Two of the three surviving patients had significant facial disfigurement. A comprehensive review of the facial NF cases reported in the literature is also provided. Based on our experience with facial NF and the results of all previous case reports, the clinical manifestations, pathogenesis, and management of this disease are discussed. 相似文献
9.
J Murtagh 《Canadian Metallurgical Quarterly》1992,21(9):1329-30, 1333-4
The outstanding cause of pain in the face is dental disease, but various neuralgias and infections such as maxillary sinusitis require consideration. A careful history and examination is the basis of diagnosis. 相似文献
10.
M von Brevern MC Hollstein JM Risk J Garde WP Bennett CC Harris KR Muehlbauer JK Field 《Canadian Metallurgical Quarterly》1998,17(16):2101-2105
From the genotyping of UK and US tylotic families with a high risk of oesophageal cancer we have previously localized the tylosis-associated cancer susceptibility gene (TOC gene, tylosis oesophageal cancer gene) to a 1 cM region on the long arm of chromosome 17 (Kelsell et al., 1996). In the present study we investigated loss of heterozygosity (LOH) patterns of 35 sporadic squamous cell carcinomas of the oesophagus using six polymorphic microsatellite markers encompassing this locus. Twenty-four of the 35 cases (69%) revealed LOH at one or more loci. Deletion was most frequently observed with the marker D17S801 (64% LOH, informative cases), which shows significant linkage to the TOC locus. The LOH analysis in sporadic oesophageal cancer we report here is thus consistent with the hypothesis that the tylosis oesophageal cancer susceptibility gene is also involved in the pathogenesis of a proportion of sporadic squamous cell carcinomas of the oesophagus. 相似文献
11.
1. The administration of 5% and 10% ethyl alcohol to mice in 7-, 14- and 28-day periods resulted in an increase in triglycerides, total lipids and cholesterol concentration in the liver and a decrease in the muscle. 2. The smallest changes were in the kidney. 相似文献
12.
EC Gendler 《Canadian Metallurgical Quarterly》1997,15(4):561-567
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Cadherin cell-cell adhesion molecules form membrane-spanning molecular complexes that couple homophilic binding by the cadherin ectodomain to the actin cytoskeleton. A fundamental issue in cadherin biology is how this complex converts the weak intrinsic binding activity of the ectodomain into strong adhesion. Recently we demonstrated that cellular cadherins cluster in a ligand-dependent fashion when cells attached to substrata coated with the adhesive ectodomain of Xenopus C-cadherin (CEC1-5). Moreover, forced clustering of the ectodomain alone significantly strengthened adhesiveness (Yap, A.S., W.M. Brieher, M. Pruschy, and B.M. Gumbiner. Curr. Biol. 7:308-315). In this study we sought to identify the determinants of the cadherin cytoplasmic tail responsible for clustering activity. A deletion mutant of C-cadherin (CT669) that retained the juxtamembrane 94-amino acid region of the cytoplasmic tail, but not the beta-catenin-binding domain, clustered upon attachment to substrata coated with CEC1-5. Like wild-type C-cadherin, this clustering was ligand dependent. In contrast, mutant molecules lacking either the complete cytoplasmic tail or just the juxtamembrane region did not cluster. The juxtamembrane region was itself sufficient to induce clustering when fused to a heterologous membrane-anchored protein, albeit in a ligand-independent fashion. The CT669 cadherin mutant also displayed significant adhesive activity when tested in laminar flow detachment assays and aggregation assays. Purification of proteins binding to the juxtamembrane region revealed that the major associated protein is p120(ctn). These findings identify the juxtamembrane region of the cadherin cytoplasmic tail as a functionally active region supporting cadherin clustering and adhesive strength and raise the possibility that p120(ctn) is involved in clustering and cell adhesion. 相似文献
15.
Recent advances have been made in the understanding of molecular events following cellular exposure to ionizing radiations, suggesting that new molecular targets could be used to modulate radio-induced cellular response, including genes and their encoded protein involved in DNA repair, signal transduction, apoptosis and cell cycle regulation. These potential molecular targets include some radio-induced cytokines and growth factors that could modulate radiation response in irradiated normal tissues (TGF beta). In addition, in order to increase tumor cell lethality after irradiation exposure, two promising approaches have been recently explored, including firstly the modulation of radiation-induced apoptosis via the transfer of genes involved in the regulation of apoptosis (p53), and secondly the modulation of double strand break DNA repair. 相似文献
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Three substance P analogs with conformation constraints in the Phe7-Phe8 region have been prepared in connection with an effort to differentiate two families of potential conformations for the binding of substance P to its NK1 receptor. While the analogs did not bind the NK1 receptor with high affinity, the synthesis of the analogs demonstrated the utility of a general method for constructing piperazinone based peptidomimetics. 相似文献
18.
Studied were the morphologic and biochemic properties of 85 Pasteurella haemolytica strains belonging to the known 12 serotypes after Biberstein, Gills (2). The biochemical properties of the strains were studied after the pattern of Bosworth and Lovell (4) with regard to arabinose, trehalose, xylose, manose, salysin, and lactose. It was found that the biochemical properties correlated with the biotype classification of the strains. Thus, the biochemical reaction with trehalose and arabinose may be used as a characteristic feature in determining the biotype. The reaction proved more dependable with the strains of the T biotype as compared to those of the A biotype, as not all strains of the A biotype fermented arabinose in the course of the first seven days, while with the strains of the T biotype trehalose was acted upon during such a period. It was also established that xylose is attacked by the strains of the A biotype only, and manose and salycin--by the strains of the T biotype, which did not ferment lactose. All strains of Pasteurella haemolytica turned out to be negative so far as the production and indol was concerned; they were shown to reduce the nitrates into nitrites, were MP and VP negative, and gave growth in McConkey's agar medium. 相似文献
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Discusses the relationship between advancing technology (the substance) and good scientific theory (the shadow) in industrial/organizational psychology. Solutions presented for bridging the gap between social science and social technology include utilization of a teamwork approach to understanding problems of human abilities, motivations, and interpersonal behavior. Avoiding being prematurely "locked into" a concept before all alternatives are considered, and the incorporation of real-world data into controlled experimental settings, are advocated. Other methods include construction of models and theories that can be revised and updated as new data are supplied, and the strengthening of informational links between the 2 disciplines. (74 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
20.
Parenting and familial influences on substance use and substance use disorders (SUDs) are important areas of study both for theories of etiology and for the development of preventive and treatment interventions. The articles in this special section illustrate both the value and the challenges of studying parenting and familial influences. Noteworthy issues include the need for mediational and moderational models examining the processes by which familial influences operate in a longitudinal framework to consider outcomes in a developmental context. Future directions include a multidisciplinary expansion of these studies. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献