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31.
Reduction of capsular polysaccharide production in Klebsiella pneumoniae by sodium salicylate. 总被引:3,自引:3,他引:3
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Heavily encapsulated Klebsiella pneumoniae (serotypes 1 and 2) was cultured in the presence of sodium salicylate. The addition of salicylate (2 to 30 micrograms/ml) progressively decreased the amount of capsular polysaccharide produced by all strains without significantly inhibiting cell growth. Further addition of salicylate (50 to 200 micrograms/ml) was progressively inhibitory to cell growth and decreased the production of polysaccharide only slightly. The optimal concentration of salicylate that could reduce the polysaccharide production of heavily encapsulated, virulent strains by 50% or more was 30 micrograms/ml. Mutants of these bacteria that produced less capsule were affected by salicylate to a lesser degree. All concentrations of salicylate tested were physiologically achievable in humans and within the therapeutic range of aspirin. The addition of calcium and magnesium partially reversed the effects of salicylate on polysaccharide production. Chelating agents, particularly EGTA [ethylene-bis(oxyethylenenitrile)tetraacetic acid], reduce capsule production as salicylate did. Thus, the chelation of calcium and magnesium by salicylate could account, at least in part, for the reduction of capsule. Optical density measurements allowed for rapid monitoring of capsule production in various culture media because a large part of culture turbidity was apparently due to the capsule. Decreased production of the primary K. pneumoniae virulence factor with salicylate may have therapeutic potential. 相似文献
32.
Luiza Guilherme Ed cio Cunha Neto Guilherme Renesto Anna C. Goldberg Josely Chiarella Rachel Snitcowsky Ma. Helena Kiss Cl vis Silva Jorge Kalil 《Human immunology》1996,47(1-2):20
β-hemolytic streptococcal infection in developing countries still causes thousands of cases of Rheumatic Fever (RF). Molecular mimicry between streptococcal M protein (strep M) and heart components has been proposed as the triggering factor leading to autoimmunity in individuals with genetic susceptibility, which is linked to different HLA-DR alleles in different populations. In our hands, RF was significantly associated to HLA-DR7/53. Previous work in our lab has shown that heart-infiltrating T cells that simultaneously recognize strep M and heart proteins. Further, such T cells predominantly recognized the 81-103 strep M5 epitope. In this work, we analysed the proliferative response of peripheral blood mononuclear cells of 99 RF patients and 40 normal controls. Eighty-nine of the RF patients were HLA-typed. As among heart-infiltrating T cells, the 81-103 strep M5 protein epitope is the most frequently recognized epitope among RF PBMC (35.4%), against a 7.5% frequency of proliferation among normal controls (p=0.0018, chi square). However, the 81-103 epitope was as frequently recognized by HLA-DR7,53 positive as by negative individuals (45.2% vs 54.8%, respectively). Taken together, the results suggest that the 81-103 strep M5 epitope may be the immunodominant epitope, “promiscuously” recognized by T cells in a genetically diverse population. The demonstration that molecular mimicry is targeted to a discrete immunodominant “promiscuous” epitope in strep M5 may allow the development of a safe anti-streptococcal synthetic vaccine devoid of such epitopes. 相似文献
33.
Telfer JF; Thomson AJ; Cameron IT; Greer IA; Norman JE 《Human reproduction (Oxford, England)》1997,12(10):2306-2312
Superoxide, an agent which attenuates the half-life of nitric oxide, is
metabolized and synthesized by superoxide dismutase (SOD) and xanthine
oxidase, respectively. Over the last few years much work has focused on the
role of nitric oxide in human parturition. The aim of this study was to
determine whether the onset of human parturition is associated with a
change in the expression of copper/zinc superoxide dismutase (Cu/Zn SOD),
manganese superoxide dismutase (Mn SOD) or xanthine oxidase within the
uterus. Samples of myometrium, placenta, decidua and fetal membranes were
obtained from women before and after the onset of labour at term.
Immunocytochemistry was used to localize Cu/Zn SOD, Mn SOD and xanthine
oxidase and measure SOD enzyme activity. Cu/Zn and Mn SOD-like
immunoreactivity was detected in syncytiotrophoblast cells, villous stromal
cells and endothelial cells of blood vessels in the placenta. In the
myometrium Cu/Zn and Mn SOD were localized to myocytes and endothelial
cells and to some vascular smooth muscle cells. In the fetal membranes we
observed staining for Cu/Zn SOD and Mn SOD in the amnion, chorion,
extravillous trophoblast and decidua. There was no difference in SOD enzyme
activity or staining intensity for SOD between different cell types before
and during labour. Xanthine oxidase immunoreactivity was identified in each
of the tissues examined and again there was no difference in immunostaining
in tissues obtained from women delivered before or after the onset of
labour. These results show that the pregnant uterus is capable of both
synthesizing and degrading superoxide and suggest that superoxide dismutase
and xanthine oxidase may play a role in the maintenance of uterine
quiescence during pregnancy, but not in the initiation of parturition.
相似文献
34.
Pinheiro PS Rodrigues RJ Silva AP Cunha RA Oliveira CR Malva JO 《Neuroscience letters》2003,336(2):97-100
Alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors have been identified mostly as postsynaptic receptors mediating fast glutamatergic synaptic transmission. However, neurochemical studies based on the modulation of neurotransmitter release have suggested the existence of presynaptic AMPA receptors. We have used a recently described technique that allows a high-purity fractionation of the pre- and postsynaptic proteins of synaptic junctions to evaluate the distribution of the different AMPA receptor subunits in rat hippocampal synapses. Surprisingly, we found very high levels of GluR1- and GluR2/3-like immunoreactivity in the presynaptic fraction, but also in the postsynaptic and extrasynaptic fractions. GluR4-like immunoreactivity was much less abundant but was still detected, predominantly in the postsynaptic fraction. This methodology appears to be far more sensitive than the classical immunogold electron microscopy to determine the localization of synaptic receptors. 相似文献
35.
Infection of Vero cells with African swine fever virus (ASFV) resulted in a marked increase in ribonucleotide reductase activity. The induction of ribonucleotide reductase was detected early after infection and was proportional to the multiplicity of infection. Inhibition of viral DNA replication did not affect the induction of the enzyme. Several characteristics could distinguish the virus-induced from the normal cell enzyme. ASFV-induced ribonucleotide reductase was inhibited by magnesium, was more strongly inhibited by hydroxyurea, and had a fourfold lower Km. The virus-induced enzyme was inhibited by deoxyribonucleoside triphosphates and by ATP. The isolation of hydroxyurea-resistant ASFV mutants provided genetic evidence for the viral origin of the induced ribonucleotide reductase. The resistance to hydroxyurea was due to a threefold overproduction of ribonucleotide reductase, as compared to enzyme induction by wild-type ASFV. Hydroxyurea had similar effect in vitro on ribonucleotide reductases induced by wild-type or mutant virus. The gene for the small subunit of the viral enzyme was mapped within a 2.3-kb fragment by hybridization with an oligonucleotide probe designed from a conserved aminoacid sequence of eukaryotic and viral ribonucleotide reductases. 相似文献
36.
Hydrosalpinges adversely affect markers of endometrial receptivity 总被引:22,自引:10,他引:22
Meyer WR; Castelbaum AJ; Somkuti S; Sagoskin AW; Doyle M; Harris JE; Lessey BA 《Human reproduction (Oxford, England)》1997,12(7):1393-1398
While in-vitro fertilization (IVF) was initially developed in women with
tubal factor infertility, recent clinical studies have suggested that the
presence of hydrosalpinges lowers implantation and pregnancy rates. We
postulated that these hydrosalpinges cause impaired endometrial
receptivity. A total of 103 women with hydrosalpinges were prospectively
evaluated, and compared with 55 infertile and 44 fertile controls. All
women had endometrial biopsies during the window of implantation, analysed
by conventional histological criteria, and also stained for three integrin
markers of endometrial receptivity (alpha1beta1, alpha4beta1 and alpha
vbeta3). Women with hydrosalpinges (cases) expressed significantly less of
the alpha vbeta3 integrin compared with controls. There was no difference
in expression of alpha1beta1 or alpha4beta1 among groups. A significantly
greater number of cases had out of phase histology and missing alpha vbeta3
(type I defects) and absent integrin expression despite normal histological
maturation (type II) defects, compared with controls. Of 20 women with
impaired endometrial receptivity who were also biopsied after hydrosalpinx
surgery, 70% demonstrated increased alpha vbeta3 expression. Seventy-seven
percent of type I and 57% of type II defects were corrected
postoperatively. Using markers of endometrial receptivity, this study
demonstrates that inflammatory hydrosalpinges have an adverse effect on
endometrial receptivity, which in some cases may be overcome by surgical
treatment of the hydrosalpinx.
相似文献
37.
R. C. P. Lima-Júnior D. I. M. Sousa G. A. C. Brito G. M. Cunha M. H. Chaves V. S. N. Rao F. A. Santos 《Inflammation research》2007,56(12):487-494
Objective and design: We previously described the visceral antinociceptive property of α, β-amyrin in a mouse model of cystitis induced by cyclophosphamide
(CPM). This study examined the contribution of vanilloid-1 (TRPV1), peripheral NK1 receptors to CPM-evoked nociceptive behaviors
and bladder edema, and its possible modulation by α, β-amyrin.
Methods: The effect of α, β-amyrin (10, 30, and 100 mg/kg, p. o.) and N-acetylcysteine (NAC) on CPM (400 mg/kg, i. p.)-induced cystitis
was studied in mice. Sensory deafferentation was done by a high dose capsaicin. The parameters analysed were: CPM-evoked noxious
behaviors, bladder edema, vascular permeability, and NK1 immunoreactivity. To assess the role of K+
ATP channels in α, β-amyrin effect, animals were pretreated with glibenclamide.
Results: α, β-amyrin (30 and 100 mg/kg) and NAC significantly (p < 0.01) suppressed the visceral pain-related behaviors and NK1 immunoreactivity, but bladder edema was reduced weakly. Glibenclamide reversed the effects of α, β-amyrin. Sensory deafferentation
by capsaicin significantly reduced the nociceptive responses and the NK1 immunoreactivity to noxious stimulation by CPM.
Conclusions: α, β-amyrin attenuates CPM-induced visceral pain and bladder edema by mechanisms that involve, at least in part, a block either
of Substance P release or its receptor function, and partly by opening K+
ATP channels.
Received 13 February 2007; returned for revision 13 April 2007; accepted by G. Geisslinger 14 May 2007 相似文献
38.
da Cunha JP Nakayasu ES Elias MC Pimenta DC Téllez-Iñón MT Rojas F Muñoz MJ Manuel M Almeida IC Schenkman S 《Molecular and biochemical parasitology》2005,140(1):75-86
Histone H1 of most eukaryotes is phosphorylated during the cell cycle progression and seems to play a role in the regulation of chromatin structure, affecting replication and chromosome condensation. In trypanosomatids, histone H1 lacks the globular domain and is shorter when compared with the histone of other eukaryotes. We have previously shown that in Trypanosoma cruzi, the agent of Chagas' disease, histone H1 is phosphorylated and this increases its dissociation from chromatin. Here, we demonstrate using mass spectrometry analysis that T. cruzi histone H1 is only phosphorylated at the serine 12 in the sequence SPKK, a typical cyclin-dependent kinase site. We also found a correlation between the phosphorylation state of histone H1 and the cell cycle. Hydroxyurea and lactacystin, which, respectively, arrest parasites at the G1/S and G2/M stages of the cell cycle, increased the level of histone H1 phosphorylation. Cyclin-dependent kinase-related enzymes TzCRK3, and less intensely the TzCRK1 were able to phosphorylate histone H1 in vitro. Histone H1 dephosphorylation was prevented by treating the parasites with okadaic acid but not with calyculin A. These findings suggest that T. cruzi histone H1 phosphorylation is promoted by cyclin dependent kinases, present during S through G2 phase of the cell cycle, and its dephosphorylation is promoted by specific phosphatases. 相似文献
39.
de Cunha DA Eadie LH Barbur JL Hawkes DJ Seifalian AM 《Computers in biology and medicine》2004,34(7):615-632
Some medical applications rely on the use of colour in the diagnostic process, even when poor colour reproduction can affect diagnosis. In this paper, we investigate the effect colour distortion can have on assessment of livers for possible transplantation. We compare the diagnostic effects for the likely colour shifts when illuminant and camera remain uncalibrated or when a monitor is incorrectly calibrated. We describe methods that can result in accurate reproduction of image colour on visual displays and determine whether accurate colour reproduction is necessary for effective liver assessment. 相似文献
40.
Gil LH Alves FP Zieler H Salcedo JM Durlacher RR Cunha RP Tada MS Camargo LM Camargo EP Pereira-da-Silva LH 《Journal of medical entomology》2003,40(5):636-641
Studies on seasonal anopheline fauna variation were performed in two distinct settlements in the State of Rond?nia, Brazil: one at the Madeira River banks (Portuchuelo) with stable native Amazonian population; the other at an inland lumber-extracting farm (Urupá) in dry land, in which adults are mostly migrants. During a 6-yr period (1994-2000), 8,638 adult anophelines were collected: 2,684 in Urupá and 5,954 in Portuchuelo. Anopheles darlingi represented >95% of total mosquitoes caught. Dissection of 4,424 A. darlingi females yielded a very low sporozoite infection index below 0.1%. Oocysts were found in both localities in approximately 0.1% of dissected mosquitoes. Determination of the hour biting rates disclosed seasonal variations in both localities. However, in Portuchuelo, mosquito density peaked at the acme of the rainy season, whereas at Urupá it peaked in the dry season. The increase in mosquito density and incidence of malaria cases were coincident. The high mosquito densities observed in the riverine settlement of Portochuelo sector B, which permits evaluation in > 10,000 mosquitoes' bites/person/year, could explain, in spite of the low mosquito's infection index, the previously described development of natural immunity in the local population that is not observed in the dry land agroindustrial settlement of Urupá. 相似文献