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1.
J Med Eng Technol ; 42(3): 203-216, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29798696

RESUMO

Electric activity of brain gets disturbed prior to epileptic seizure onset. Early prediction of an upcoming seizure can help to increase effectiveness of antiepileptic drugs. The scalp electroencephalogram signals contain information about the dynamics of brain and have been used to predict an upcoming seizure and localise its zone. The objective of this paper is to localise the epileptogenic region and predict an upcoming seizure at the earliest. To localise epileptogenic region, Electroencephalogram signals are categorised into four regions of brain (Frontal, Temporal, Parietal and Central). For each signal seventy-two (72) parameters in frequency domain have been extracted by using ten minute non overlapping window. Four prominent ratio parameters, γ1/γ5, γ3/γ1, θ/γ2 and γ4/θ have been identified as best parameters based on relative fisher score. Zone 2 shows the highest change in all the parameters as compared to the other zones. So, temporal region is identified as the epileptogenic region in this work. For prediction of the epileptic seizure machine learning algorithm artificial neural network (ANN) is proposed. The proposed machine learning algorithm has an accuracy of 92.3%, sensitivity of 100% and specificity of 83.3%.


Assuntos
Algoritmos , Eletroencefalografia/métodos , Epilepsia/diagnóstico , Aprendizado de Máquina , Convulsões/diagnóstico , Encéfalo/fisiopatologia , Epilepsia/fisiopatologia , Humanos , Redes Neurais de Computação , Reprodutibilidade dos Testes , Convulsões/fisiopatologia
2.
J Natl Cancer Inst ; 62(4): 983-8, 1979 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-285299

RESUMO

The effect of 3-methylcholanthrene (MCA) on the phagocytic activity of mouse peritoneal macrophages for Torulopsis glabrata was investigated. Macrophages were maintained in glass scintillation vials or on cover slips in Leighton tubes with the use of Hanks' balanced salt solution plus 30% horse serum. Graded amounts of MCA were incorporated into the medium and the macrophages were parasitized with viable cells of T. glabrata. Macrophages from C3H mice, a strain highly susceptible to MCA carcinogenesis, were more prone to the suppressive effect of MCA than were the macrophages from CFW mice, a relatively resistant strain. Significant suppressive effect on phagocytosis of macrophages from C3H mice was observed with 5 micrograms MCA/ml, whereas up to 50 micrograms MCA/ml did not alter the phagocytic activity of CFW macrophages. However, 100 micrograms MCA/ml also suppressed the phagocytosis of CFW macrophages. Suppression in phagocytosis of C3H macrophages was observed after 6 hours' exposure to MCA, whereas a similar effect on CFW macrophages was seen after 12 hours. Treatment with 100 micrograms MCA/ml imparied the fungicidal activity of both C3H and CFW macrophages. These results indicate a correlation between the suppressive effect of MCA on macrophage activity and the strain susceptibility of mice to chemical carcinogenesis.


Assuntos
Macrófagos/efeitos dos fármacos , Metilcolantreno/farmacologia , Fagocitose/efeitos dos fármacos , Animais , Líquido Ascítico/imunologia , Candida/imunologia , Macrófagos/imunologia , Masculino , Camundongos , Camundongos Endogâmicos C3H , Neoplasias Experimentais/induzido quimicamente , Especificidade da Espécie , Fatores de Tempo
3.
Int J Biol Macromol ; 93(Pt B): 1639-1646, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27126167

RESUMO

Supramolecular hydrogel as a novel drug carrier was prepared from N-(9-Fluorenylmethoxycarbonyl) (Fmoc) modified l-phenylalanine. Its different properties like stability at different pH, temperature and rheology were evaluated in reference to salicylic acid (SA) as a model drug, entrapped in the supramolecular hydrogel network. The release behaviour of SA drug in supramolecular hydrogel was investigated by UV-vis spectroscopy. The influence of hydrogelator, pH values of the accepting media, temperature and concentration of SA drug on the release behaviour was investigated under static conditions. The results indicated that the release rate of SA in the supramolecular hydrogels was slightly retarded with an increase of the hydrogelator concentration. Also, the release rates of SA increased with an increase of temperature and its concentration. Furthermore, the release behaviour of SA was found to be different at various pH values in buffers. The study of the release kinetics indicated that the release behaviour of SA from the carrier was in accord with the Peppas model and the diffusion controlled mechanism involved in the Fickian model.


Assuntos
Portadores de Fármacos/química , Hidrogéis/química , Fenilalanina/análogos & derivados , Fenilalanina/química , Ácido Salicílico/química , Antibacterianos/química , Antibacterianos/farmacologia , Portadores de Fármacos/farmacologia , Composição de Medicamentos , Liberação Controlada de Fármacos , Fluorenos/química , Humanos , Hidrogéis/farmacologia , Teste de Materiais , Testes de Sensibilidade Microbiana , Fenilalanina/farmacologia , Polimerização , Staphylococcus aureus/efeitos dos fármacos
4.
Arch Intern Med ; 149(2): 302-4, 1989 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-2916875

RESUMO

A radioimmunoassay was previously developed for detection of Histoplasma capsulatum antigen in the blood and urine of patients with disseminated histoplasmosis. In this investigation, cerebrospinal fluid (CSF) specimens from 14 episodes of Histoplasma meningitis occurring in 12 patients were tested by radioimmunoassay. Histoplasma capsulatum antigen was detected in the CSF of five patients. Cerebrospinal fluid cultures were positive for H capsulatum in three of these five patients. Antibodies to H capsulatum were found in nine of the 13 CSF specimens tested. The radioimmunoassay for Histoplasma antigen was also positive in the CSF in one of 11 patients with coccidioidal meningitis but not in 17 patients with cryptococcal meningitis. It was concluded that Histoplasma antigen is present in the CSF of some patients with histoplasmosis and chronic meningitis, but cross-reactions may occur in patients with coccidioidal meningitis.


Assuntos
Antígenos de Fungos/líquido cefalorraquidiano , Histoplasma/isolamento & purificação , Histoplasmose/diagnóstico , Meningite/etiologia , Histoplasmose/complicações , Humanos , Meningite/líquido cefalorraquidiano
5.
J Biomater Appl ; 29(9): 1314-25, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25492055

RESUMO

In the present study gentamicin was encapsulated within calcium alginate beads and incorporated into porous chitosan, gelatin, double-hybrid silk fibroin, chitosan/gelatin and double-hybrid silk fibroin/chitosan scaffolds. Physiochemical, morphological and biological properties of fabricated amenable model systems were evaluated, revealing hemocompatible nature of double-hybrid silk fibroin/chitosan and double-hybrid silk fibroin scaffolds of hemolysis %<5 and porosity >85%. Fourier transform infrared results confirmed the blend formation and scanning electron microscope images showed good interconnectivity. Double-hybrid silk fibroin/chitosan-blended scaffold shows higher compressive strength and compressive modulus than other fabricated scaffolds. A comparative drug release profile of fabricated scaffolds revealed that double-hybrid silk fibroin/chitosan scaffold is a pertinent model system because of its prolonged drug release, optimal hemocompatability and high compressive modulus.


Assuntos
Materiais Biocompatíveis/química , Gentamicinas/administração & dosagem , Alicerces Teciduais/química , Alginatos/química , Animais , Antibacterianos/administração & dosagem , Bombyx , Quitosana/química , Força Compressiva , Sistemas de Liberação de Medicamentos , Ácido Glucurônico/química , Hemólise , Ácidos Hexurônicos/química , Humanos , Técnicas In Vitro , Teste de Materiais , Microscopia Eletrônica de Varredura , Porosidade , Seda/química , Espectroscopia de Infravermelho com Transformada de Fourier , Staphylococcus aureus/efeitos dos fármacos
6.
Chest ; 95(5): 1158-60, 1989 May.
Artigo em Inglês | MEDLINE | ID: mdl-2707076

RESUMO

A 79-year-old retired schoolteacher had a history of bronchiectasis. She developed recurrent hemoptysis requiring multiple blood transfusions. Exophiala dermatitidis was cultured repeatedly from bronchial lavages. To our knowledge, this is the first documented case of isolated pulmonary phaeohyphomycosis due to E dermatitidis, and it was successfully treated with amphotericin B and 5-fluocytosine.


Assuntos
Hemoptise/etiologia , Pneumopatias Fúngicas/complicações , Micoses/complicações , Idoso , Exophiala , Feminino , Humanos , Pneumopatias Fúngicas/diagnóstico , Micoses/diagnóstico
7.
Indian J Chest Dis Allied Sci ; 42(4): 265-9, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-15597673

RESUMO

The cellular and molecular mechanisms of host defenses to histoplasmosis, a prototype of respiratory fungal infections are described. Although, cell-mediated acquired immunity is considered as a hallmark of protective immunity to histoplasmosis, the recent findings provide mounting evidence on the importance of natural cellular immunity in host resistance to fungal infections. The natural immunity to Histoplasma capsulatum infection is primarily mediated by natural killer cells, endothelial cells and platelets but mechanisms of intercellular communication and their interactions with the pathogen are not clearly defined.


Assuntos
Histoplasmose/imunologia , Pneumopatias Fúngicas/imunologia , Micoses/imunologia , Plaquetas/imunologia , Células Endoteliais/imunologia , Histoplasma/imunologia , Histoplasma/patogenicidade , Humanos , Células Matadoras Naturais/imunologia , Fagocitose
9.
Acta Microbiol Pol ; 28(4): 311-4, 1979.
Artigo em Inglês | MEDLINE | ID: mdl-94749

RESUMO

Investigations on the rhizosphere mycoflora of healthy and virus (YVMV) infected okra plants showed a higher fungal population in the rhizosphere of healthy plants at preflowering and post-flowering stages than in that of diseased ones. Maximum population was observed during flowering both in healthy and diseased plant rhizosphere as well as in non-rhizosphere soil. However, virus infected plants showed a higher population at the flowering stage than healthy ones. The quantitative differences in the rhizosphere of healthy and diseased plants during flowering seem to be due to a change in C/N ratio and amino acids. The drastic reduction in diseased plant rhizospheres during the post-flowering stage may be due to either change in C/N ratio unfavourable to mycoflora or production of some toxic substances inhibiting multiplication of the mycoflora.


Assuntos
Vírus do Mosaico/isolamento & purificação , Doenças das Plantas , Verduras , Densidade Demográfica , Microbiologia do Solo
10.
J Bacteriol ; 95(3): 1130-9, 1968 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-5689332

RESUMO

An experimental infection was induced in mice by intravenous and intraperitoneal inoculation with Oidiodendron kalrai. The infected mice developed a complex neurological syndrome consisting of hyperirritability, jumping, circling, and ataxia, followed by coma and death or by apparent recovery. Visible lesions accompanied by inflammatory reaction and fungal elements were seen only in kidneys, but organisms were also identified in and isolated from the liver, spleen, lungs, and brain. Cortisone alone or in combination with streptomycin rendered the mice highly susceptible to infection with O. kalrai, and lesions were found in the brains as well as in the kidneys of these mice. Treatment of infected mice with streptomycin alone increased the severity and duration of the neurological syndrome, but such treatment did not increase the mortality rate.


Assuntos
Candidíase , Fungos Mitospóricos/patogenicidade , Doenças do Sistema Nervoso/etiologia , Animais , Encéfalo/patologia , Candidíase/patologia , Cortisona/efeitos adversos , Rim/patologia , Pulmão/patologia , Camundongos , Estreptomicina/efeitos adversos
11.
Mycopathologia ; 58(3): 131-5, 1976 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-987534

RESUMO

The chemical composition of yeast cells of Oidiodendron kalrai was analyzed and is expressed as percent dry weight. Cultures were grown in tryptone broth and in a liquid synthetic medium containing ammonium salts as a nitrogen source. After 48 h, carbohydrate levels were higher in the synthetic medium, but lipid levels were lower, Deoxyribonucleic acid (DNA), ribonucleic acid (RNA), and protein contents did not differ significantly in the two media. The chemical components were also studied at different stages of growth. DNA remained relatively constant, but other components varied with the age of culture. The RNA was 6.6% at 18 h and declined rapidly to 5% by 24 h and remained constant, An initial protein content of 23% at 18 h increased rapidly to 37% by 48 h and gradually declined to 30% by day 10. The lipid content of 33% at 18 h decreased over the entire growth period to 10% by day 10. An initial carbohydrate level of 30% increased to a maximum of 54% by day 5 and then declined.


Assuntos
Fungos Mitospóricos/análise , Carboidratos/análise , Meios de Cultura , DNA/análise , Proteínas Fúngicas/análise , Lipídeos/análise , Fungos Mitospóricos/crescimento & desenvolvimento , RNA/análise
12.
Infect Immun ; 10(5): 1091-7, 1974 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-16558095

RESUMO

Protective immunity was elicited by immunization of mice with ribosomal preparations from yeast cells of Histoplasma capsulatum. Ribosomes from disrupted cells were isolated by differential centrifugation using sodium dodecyl sulfate. These preparations contained 55% protein and 45% ribonucleic acid and sedimented as a single peak with a sedimentation coefficient of 77S on sucrose density gradient analysis. Mice immunized subcutaneously with ribosomes, with or without adjuvant, were challenged intravenously with 8 x 10(6) yeast cells of H. capsulatum. Significant protection was induced by ribosomes and was greatly enhanced by adjuvants. Protection measured by 30-day survival compared favorably with the immunoprotection assessed by absence of lung lesions and negative spleen cultures. Treatment of ribosomes with ribonuclease before immunization reduced protection by 85%, whereas trypsin and Pronase reduced the protection by 50 to 55%. These findings indicate that both intact ribosomal ribonucleic acid and protein are necessary for maximal immunogenicity of Histoplasma ribosomes.

13.
Can J Microbiol ; 21(9): 1362-8, 1975 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-241480

RESUMO

The physiochemical characteristics of the intracellular proteolytic enzymes of Oidiodendron kalari, a neuropathogenic fungus, were studied. The organism in the yeast phase was grown in a semisynthetic medium containing 1% tryptone, at 37 degrees C for 48 hr, on a gyrotory shaker. The crude extract was prepared by breaking the cells in a French pressure cell and the proteolytci activity was tested against biological substrates. The cell-free extract hydrolyzed casein, hemoglobin, lactalbumin, gelatin, elastin, collagen and purified rabbit renal basement membrane to various degrees. Optimal proteolytic activity was observed at pH 6 and at 32 degrees C. Calcium and EDTA did not affect the enzymatic activity; however, activity was partially inhibited by sulfhydryl-blocking agents and by heat-inactivated horse, calf, and human serum. The extract was totally inactivated by exposure to a temperature of 70 degrees C for 60 min. Storage at -76 degrees C or -15 degrees C for 6 months or at 4 degrees C for 4 weeks did not affect protease activity.


Assuntos
Fungos Mitospóricos/enzimologia , Peptídeo Hidrolases/metabolismo , Animais , Membrana Basal/metabolismo , Cálcio/farmacologia , Caseínas/metabolismo , Sistema Livre de Células , Colágeno/metabolismo , Cisteína/farmacologia , Ácido Edético/farmacologia , Elastina/metabolismo , Gelatina/metabolismo , Hemoglobinas/metabolismo , Concentração de Íons de Hidrogênio , Hidrólise , Rim , Lactalbumina/metabolismo , Fungos Mitospóricos/metabolismo , Coelhos , Reagentes de Sulfidrila/farmacologia , Temperatura
14.
Can J Microbiol ; 22(3): 327-33, 1976 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-175906

RESUMO

Oidiodendron kalrai yeast-phase cells demonstrate proteolytic activity. Some of the proteolytic enzymes of the crude extract were purified by a combination of ammonium sulfate precipitation, Sephadex G-200, and diethylaminoethyl (DEAE) cellulose column chromatography. At least six proteins exhibiting a range of proteolytic activities could be identified by these procedures. Purity of the enzyme fractions obtained from the DEAE-cellulose columns was tested by running polyacrylamide gels.


Assuntos
Fungos Mitospóricos/enzimologia , Peptídeo Hidrolases/isolamento & purificação , Sulfato de Amônio , Caseínas/metabolismo , Sistema Livre de Células , Precipitação Química , Cromatografia DEAE-Celulose , Colágeno/metabolismo , Elastina/metabolismo , Gelatina/metabolismo , Hemoglobinas/metabolismo , Lactalbumina/metabolismo , Colagenase Microbiana/isolamento & purificação , Peptídeo Hidrolases/metabolismo
15.
N Engl J Med ; 314(2): 83-8, 1986 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-3941695

RESUMO

The diagnosis of Histoplasma capsulatum infection by serologic testing for the presence of antibodies is limited by a high rate of false positive and false negative results and by the requirement that the patient have a normal immune response. We have developed a radioimmunoassay for the detection of H. capsulatum antigen in urine and serum specimens. Antigenuria was noted in 20 of 22 episodes of disseminated histoplasmosis that occurred in 16 patients, in 6 of 32 patients with self-limited infection, in 2 of 32 patients with cavitary histoplasmosis, and in 4 of 8 patients with a sarcoid-like illness caused by H. capsulatum. The detection of antigen in urine was reproducible in 38 of 41 (93 percent) retests of specimens. H. capsulatum antigen was also detected in the serum during 11 of the 22 episodes of disseminated histoplasmosis, in none of the 12 episodes of other types of histoplasmosis in patients with antigenuria, in 1 of the 33 patients with histoplasmosis who lacked the urinary antigen, and in none of the 50 controls. Antigenemia and antigenuria decreased after initiation of antifungal therapy and recurred in patients who had a relapse. We conclude that this radioimmunoassay for H. capsulatum antigen represents a useful new method for the rapid diagnosis of disseminated histoplasmosis.


Assuntos
Antígenos de Fungos/análise , Histoplasma/imunologia , Histoplasmose/diagnóstico , Antígenos de Fungos/urina , Humanos , Soros Imunes , Radioimunoensaio
16.
J Med Vet Mycol ; 25(2): 107-14, 1987 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-2439674

RESUMO

The viability of Histoplasma capsulatum yeast cells grown under different conditions was determined by dye tests with Eosin-Y and Janus Green B and by colony counts of cells plated on brain-heart infusion agar supplemented with histoplasma growth factor and bovine serum albumin (BHI-SAG). The test samples included cells grown on brain-heart infusion agar at 37 degrees C for 2-7 days, cells grown in glucose-cysteine broth medium for 1-31 days, and cells grown on brain-heart infusion agar for 3 days at 37 degrees C and then irradiated by ultraviolet light. The colony count indicated that the viability of the yeast cells grown on brain-heart infusion agar for 2 or 3 days varied between 68 and 100% depending on the isolates. The viability, however, dropped from 16 to 29% by day 7. The results of dye tests showed 78 to 99% dye-negative cells among the 2- and 3-day-old cultures while the number of dye-negative cells dropped to 32-36% on day 7. The colony count with the cells grown in the broth culture showed 100% viability until day 7 and dropped significantly by day 9. The results of dye tests showed no correlation with the colony count findings. The survival curve of ultraviolet-irradiated cells determined by colony count showed that irradiation at 180 erg mm-2 killed more than 50% of cells; fewer than 10% of cells survived 360 erg mm-2. The results of the dye test showed no difference between the irradiated and control populations.(ABSTRACT TRUNCATED AT 250 WORDS)


Assuntos
Histoplasma/crescimento & desenvolvimento , Compostos Azo , Corantes , Meios de Cultura , Amarelo de Eosina-(YS) , Histoplasma/efeitos da radiação , Micologia/métodos , Coloração e Rotulagem , Raios Ultravioleta
17.
J Clin Lab Anal ; 10(5): 233-8, 1996.
Artigo em Inglês | MEDLINE | ID: mdl-8887000

RESUMO

Rats exposed to constant light develop polycystic ovarian (PCO) disease with persistent estrus, representing an estrogen-dominant condition. Herein, we report that fluctuations seen in the vaginal microflora in cyclic rats were not observed in PCO rats with persistent estrus. The vaginal-cervical mucosa of PCO rats showed numerous adherent bacteria by scanning electron microscopy, similar to that seen in proestrus and estrus rats, but unlike the diestrus rats in which fewer organisms adhered to the mucosa. Administration of human chorionic gonadotropin induced ovulation in PCO rats, which was associated with a significant decrease in serum estradiol, an increase in progesterone, and a significant decrease in the estradiol/progesterone ratio compared with baseline values (P < 0.01). This also resulted in an influx of leukocytes in the vagina with a significant decrease in vaginal anaerobic as well as aerobic bacterial flora. These data demonstrate that loss of cyclic ovarian activity in PCO rats with persistent estrus causes increased bacterial colonization of the vaginal-cervical mucosa, and the ovarian hormones appear to modulate the colonization of bacteria in the lower genital tract.


Assuntos
Hormônios Esteroides Gonadais/fisiologia , Síndrome do Ovário Policístico/microbiologia , Vagina/microbiologia , Animais , Estradiol/sangue , Feminino , Microscopia Eletrônica de Varredura , Síndrome do Ovário Policístico/sangue , Síndrome do Ovário Policístico/patologia , Progesterona/sangue , Ratos , Ratos Sprague-Dawley , Vagina/patologia , Vagina/ultraestrutura , Esfregaço Vaginal
18.
Infect Immun ; 28(1): 92-100, 1980 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-6769823

RESUMO

Protection against gonococcal infection was obtained by immunization with ribosomal preparations from Neisseria gonorrhoeae. Ribosomes were isolated from disrupted cells by differential ultracentrifugation and treatment of the microsomal fraction with 0.25% sodium dodecyl sulfate. The isolated ribosomal preparations contained 55% ribonucleic acid, 39% protein, and 0.35% carbohydrate. The ribosomal preparations contained small amounts of endotoxin as determined by thiobarbituric acid- and lead acetate-sensitized mice assays. Guinea pigs immunized subcutaneously with ribosomal preparations were challenged intrachamberially with 10(7) colony-forming units of N. gonorrhoeae, and protection was assessed by clearance of the organism from subcutaneous chambers. The ribosomal preparations elicited significant protection, which was enhanced by incoporation of the immunogen into adjuvant. This protection was comparable to that obtained with whole cells. Treatment with proteolytic enzymes destroyed the protective effect of the ribosomal preparations, but ribonuclease had no measurable effect. Passive hemagglutination and immunodiffusion tests with sera from immunized animals demonstrated the presence of antibody to the ribosomal antigens. Results of adsorption of antiribosomal sera with enzyme-treated ribosomal preparations also indicated the protein nature of the immunogen. These results indicate that protein associated with the gonococcal ribosomal preparation is the major protective immunogen. The role of endotoxin contamination in the immunogenicity of gonococcal ribosomal preparations warrants further investigation.


Assuntos
Anticorpos Antibacterianos/biossíntese , Gonorreia/imunologia , Neisseria gonorrhoeae/imunologia , Ribossomos/imunologia , Animais , Atividade Bactericida do Sangue , Endotoxinas/análise , Feminino , Cobaias , Imunização , Neisseria gonorrhoeae/ultraestrutura , Peptídeo Hidrolases/farmacologia , Ribonucleases/farmacologia , Ribossomos/análise
19.
Infect Immun ; 13(6): 1531-8, 1976 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-971940

RESUMO

Macrophage ribonucleic acid (RNA) synthesis is an important metabolic process intimately related to the function of these cells. Mouse peritoneal macrophage RNA was extracted with phenol in the presence of bentonite and electrophoresed on composite agarose-polyacrylamide gels. The pulse-chase technique was used to follow the precursor relationships in macrophage ribosomal RNA (rRNA) maturation. The rRNA species at 18S and 28S appeared at 15 and 45 min, respectively, after RNA synthesis was halted. Their appearance corresponded closely to decreases in the rRNA precursors at 45S, 36S, and 34S. Studies of RNA methylation aided in confirming the identity of these ribosomal species. Unmethylated RNA species appeared as messenger RNA between 5S and 15S, and at about 55S probably represented heterodisperse nuclear RNA. When normal macrophages were incubated with heat-killed Salmonella enteritidis, an acceleration in the maturation of RNA was observed. The accelerated maturation was indicated by the earlier appearance of 28S rRNA and the more rapid development of an equilibrium state, where further labeling did not change the RNA profile. In macrophage RNA from mice immunized with S. enteritidis, rRNA species appeared rapidly but did not accumulate to the same extent as observed for normal macrophages. Precursor rRNA and other RNA species developed as usual, suggesting specific degradation of mature rRNA. Such rRNA wastage could indicate a mechanism controlling ribosome assembly in the non-proliferating activated macrophage. The pattern of RNA synthesis in immune macrophages was essentially unchanged by the presence of heat-killed S. enteritidis in vitro.


Assuntos
Macrófagos/metabolismo , RNA/biossíntese , Animais , Antígenos de Bactérias , Eletroforese em Gel de Ágar , Eletroforese em Gel de Poliacrilamida , Macrófagos/imunologia , Camundongos , Precursores de Ácido Nucleico , Fagocitose , RNA Ribossômico/biossíntese , Salmonella/imunologia
20.
Infect Immun ; 67(11): 6034-9, 1999 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-10531264

RESUMO

While laccase of Cryptococcus neoformans is implicated in the virulence of the organism, our recent studies showing absence of melanin in the infected mouse brain has led us to a search for alternative roles for laccase in cryptococcosis. We investigated the role of laccase in protection of C. neoformans against murine alveolar macrophage (AM)-mediated antifungal activity by using a pair of congenic laccase-positive (2E-TUC) and laccase-deficient (2E-TU) strains. The laccase-positive cells with laccase derepression were more resistant to the antifungal activity of AM than a laccase-deficient strain ([28.9 +/- 1.2]% versus [40.2 +/- 2.6]% killing). Addition of L-dopa to Cryptococcus to produce melanin in a laccase-positive strain resulted in a slight increase in protection of C. neoformans from the antifungal activity of macrophages ([25.4 +/- 3.4]% versus [28.9 +/- 1.2]% killing). Recombinant cryptococcal laccase exhibited iron oxidase activity in converting Fe(II) to Fe(III). Moreover, recombinant laccase inhibited killing of C. neoformans by hydroxyl radicals catalyzed by iron in a cell-free system. Addition of the hydroxyl radical scavenger mannitol or dimethyl sulfoxide to AMs prior to the introduction of cryptococcal cells decreased killing of both strains and reduced the difference in susceptibility between the laccase-positive and laccase-deficient strains. Furthermore, laccase-mediated protection from AM killing was inhibited by the addition of Fe(II), presumably by overcoming the effects of the iron oxidase activity of cryptococcal laccase. These results suggest that the iron oxidase activity of laccase may protect C. neoformans from macrophages by oxidation of phagosomal iron to Fe(III) with a resultant decrease in hydroxyl radical formation.


Assuntos
Cryptococcus neoformans/imunologia , Macrófagos Alveolares/imunologia , Oxirredutases/farmacologia , Animais , Feminino , Radical Hidroxila , Ferro/metabolismo , Ferro/farmacologia , Lacase , Camundongos , Molsidomina/análogos & derivados , Molsidomina/farmacologia , Oxirredutases/metabolismo , Fagocitose/efeitos dos fármacos , Proteínas Recombinantes/farmacologia
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