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1.
Eur Arch Paediatr Dent ; 24(5): 585-590, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37501012

RESUMO

PURPOSE: To evaluate the reliability of YouTube™ videos on zirconia crowns in pediatric dentistry. METHODS: On January 4, 2022, a search was performed using the term "pediatric zirconia crown". The first 100 videos on the subject were included. Non-English videos, duplicates, and off-topic videos were excluded. For each video, an examiner recorded the number of views, likes, comments, channel followers, upload date, duration, and category rating. Two examiners assessed the reliability of the information presented in the videos using DISCERN, a brief questionnaire and scale score used to assess in a valid and reliable way the quality of information on treatment choices for health problems. Descriptive and inferential analyses were performed (p < 0.05). RESULTS: Of the initial 100 videos, 72 were excluded because of language, duplication, and subject matter. The 28 remaining videos had an average of 3.5 comments, 8,896.18 channel followers, 5,614.00 views, 19.14 likes, and a duration of 840.32 s. The average view rate was 7.54 per day ± 10,206.81. There was a statistically significant difference between the number of views and comments (p < 0.001), likes and comments (p < 0.001), and likes and views (p = 0.006). According to the DISCERN, none of the videos received the maximum grade to be considered very good. Two were considered good, nine fair, fourteen poor, and three very poor. CONCLUSION: Given that the majority of YouTube™ videos currently available on zirconia crowns in pediatric dentistry were deemed unreliable according to the DISCERN questionnaire, caution should be exercised when using the information presented.


Assuntos
Odontopediatria , Mídias Sociais , Humanos , Criança , Reprodutibilidade dos Testes , Gravação em Vídeo , Coroas
2.
Acta Trop ; 233: 106552, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35671784

RESUMO

Chagas disease is potentially life-threatening and caused by the protozoan parasite Trypanosoma cruzi. The parasite cannot synthesize some lipids and depends on the uptake of these lipids from its vertebrate and invertebrate hosts. To achieve this, T. cruzi may need to modify the physiology of the insect host for its own benefit. In this study, we investigated the interaction of T. cruzi (Y strain) with its insect vector Rhodnius prolixus and how it manipulates the vector lipid metabolism. We observed a physiological change in lipid flux in of infected insects. In the fat body of infected insects, triacylglycerol levels decreased by 80.6% and lipid storage droplet-1(LSD-1) mRNA levels were lower, when compared to controls. Lipid sequestration by infected midguts led to increased levels of 5' AMP-activated protein kinase (AMPK) phosphorylation and activation in the fat body, inhibiting the synthesis of fatty acids and stimulating their oxidation. This led to reduced lipid levels in the fat body of infected insets, despite the fact that T. cruzi does not colonize this tissue. There was a 3-fold increase, in lipid uptake and synthesis in the midgut of infected insects. Finally, our results suggest that the parasite modifies the lipid flux and metabolism of its vector R. prolixus through the increase in lipid delivery from the fat body to midgut that are then scavenge by T cruzi.


Assuntos
Doença de Chagas , Rhodnius , Trypanosoma cruzi , Animais , Doença de Chagas/parasitologia , Metabolismo dos Lipídeos , Fosfolipídeos/metabolismo , Rhodnius/parasitologia , Trypanosoma cruzi/fisiologia
3.
J Helminthol ; 93(2): 203-207, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29655389

RESUMO

A new species of Dendrorchis is described and compared with others in the genus. The parasites were found in the swim bladder of the annual killifish Cynopoecilus melanotaenia. Hosts were collected from a seasonal wetland in southern Brazil. The main characteristics of D. pampae are: genital pore in the intestinal bifurcation region elongate and lobed vitellaria uterine loops limited to the acetabular region and to the rear end of the body; and wide intestinal caeca. An emended diagnosis of the genus Dendrorchis includes the characteristics of the new species. This is the first record of an adult digenean in an annual killifish from South America.


Assuntos
Estruturas Animais/parasitologia , Ciprinodontiformes/parasitologia , Trematódeos/classificação , Animais , Brasil , Trematódeos/anatomia & histologia , Trematódeos/isolamento & purificação , Áreas Alagadas
4.
Parasitol Res ; 117(8): 2445-2456, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29858940

RESUMO

ABTRACT: Structure of the helminth community of Megaleporinus obtusidens collected in Lake Guaíba was evaluated, and the results indicated that the diversity of helminth species was probably determined by fish behavior and eating habits. The influence of sex, weight, and standard length of hosts for parasitic indices was also analyzed. Sixteen helminth species were found parasitizing M. obtusidens, including the following: platyhelminths, with the highest richness, represented by one species of Aspidobothrea; four species of Digenea; and eight species of Monogenea; the latter, presented the highest prevalence. Rhinoxenus arietinus, found in nasal cavities, had the greater abundance, and was the only species classified as core. The prevalence of Urocleidoides paradoxus was significantly influenced by the sex of the host; females had the highest values. Abundance was weakly influenced by fish weight and the body length of the hosts. Urocleidoides sp. had its abundance weakly influenced by the host weight. The other helminths were not influenced by biometric characteristics of the hosts. The total species richness was similar between male and female fish, and both had 14 helminth species of parasites.


Assuntos
Caraciformes/parasitologia , Doenças dos Peixes/parasitologia , Helmintíase Animal/parasitologia , Helmintos/isolamento & purificação , Lagos/parasitologia , Animais , Biodiversidade , Feminino , Helmintos/classificação , Helmintos/genética , Masculino , Prevalência
5.
Phys Rev Lett ; 120(13): 132504, 2018 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-29694208

RESUMO

A new method to tag the barium daughter in the double-beta decay of ^{136}Xe is reported. Using the technique of single molecule fluorescent imaging (SMFI), individual barium dication (Ba^{++}) resolution at a transparent scanning surface is demonstrated. A single-step photobleach confirms the single ion interpretation. Individual ions are localized with superresolution (∼2 nm), and detected with a statistical significance of 12.9σ over backgrounds. This lays the foundation for a new and potentially background-free neutrinoless double-beta decay technology, based on SMFI coupled to high pressure xenon gas time projection chambers.

6.
Sci Rep ; 8: 46942, 2018 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-29430010

RESUMO

This corrects the article DOI: 10.1038/srep41699.

7.
Med Vet Entomol ; 32(1): 41-47, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-28833280

RESUMO

The cattle tick, Rhipicephalus microplus (Canestrini, 1888) (Ixodida: Ixodidae), is the most important ectoparasite in cattle-breeding areas and is responsible for severe economic losses. Synthetic acaricides have been used to control this parasite. However, the need for safer products has stimulated the search for new acaricides, such as those to be obtained from medicinal plants. The essential oil of Syzygium aromaticum (clove) has many biological properties and shows great potential for use in veterinary applications. In the context of the need for new agents, this study investigated the in vitro properties of the hydrolate, essential oil and the main constituent of S. aromaticum, eugenol, in formulated and free applications against larvae and females of R. microplus. Eugenol and the essential oil caused 100% mortality in larvae at starting applications of 2.5 mg/mL and 5.0 mg/mL, respectively. The hydrolate showed no activity. Both eugenol and essential oil had good efficacy in adult immersion tests at 50 mg/mL and achieved 100% efficacy at a concentration of 100 mg/mL. The results of these tests reaffirm the important potential of clove essential oil and eugenol.


Assuntos
Acaricidas , Óleo de Cravo , Eugenol , Rhipicephalus , Syzygium/química , Controle de Ácaros e Carrapatos , Animais , Feminino , Larva/crescimento & desenvolvimento , Rhipicephalus/crescimento & desenvolvimento
8.
Sci Rep ; 7: 41699, 2017 02 09.
Artigo em Inglês | MEDLINE | ID: mdl-28181520

RESUMO

The high neutron detection efficiency, good gamma-ray discrimination and non-toxicity of 3He made of proportional counters filled with this gas the obvious choice for neutron detection, particularly in radiation portal monitors (RPM), used to control the illicit transport of nuclear material, of which neutron detectors are key components. 3He is very rare and during the last decade this gas has become increasingly difficult to acquire. With the exception of BF3, which is toxic, no other gas can be used for neutron detection in proportional counters. We present an alternative where the 3He atoms are replaced by nanoparticles made of another neutron sensitive material, 10B. The particles are dispersed in a gaseous volume, forming an aerosol with neutron sensitive properties. A proportional counter filled with such aerosol was exposed to a thermal neutron beam and the recorded response indicates that the neutrons have interacted with the particles in the aerosol. This original technique, which transforms a standard proportional gas mixture into a neutron sensitive aerosol, is a breakthrough in the field of radiation detection and has the potential to become an alternative to the use of 3He in proportional counters.

9.
Med Vet Entomol ; 30(4): 377-382, 2016 12.
Artigo em Inglês | MEDLINE | ID: mdl-27392803

RESUMO

The effects of combinations of the monoterpenes thymol and carvacrol and the phenylpropanoid eugenol in larvae of Rhipicephalus microplus (Canestrini, 1888) (Acari: Ixodidae) and Rhipicephalus sanguineus sensu lato (s.l.) (Acari: Ixodidae) were assessed by the larval packet test. The CompuSyn program was used to make qualitative assessments of the effects (synergistic, additive and antagonistic) of the associations. The effects of all combinations tested against R. microplus larvae were synergistic, with combination indices (CIs) <0.70. When tested against R. sanguineus, eight of the mixtures showed a synergistic effect (CI < 0.70); only the carvacrol + thymol mixture at LC50 presented a moderate synergistic effect, with CIs between 0.70-0.90. This study is the first to determine the effects of the interactions of these substances in the control of these two tick species. The combinations of carvacrol + thymol, carvacrol + eugenol and thymol + eugenol have synergistic effects in R. microplus and R. sanguineus s.l. larvae.


Assuntos
Acaricidas , Eugenol , Monoterpenos , Rhipicephalus , Timol , Animais , Cimenos , Sinergismo Farmacológico , Larva/crescimento & desenvolvimento , Rhipicephalus/crescimento & desenvolvimento , Rhipicephalus sanguineus/crescimento & desenvolvimento
10.
Braz J Med Biol Res ; 49(7)2016 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-27332772

RESUMO

This study aimed to describe the association of Borrelia burgdorferi s.s. with ixodid tick cell lines by flow cytometry and fluorescence and confocal microscopy. Spirochetes were stained with a fluorescent membrane marker (PKH67 or PKH26), inoculated into 8 different tick cell lines and incubated at 30°C for 24 h. PKH efficiently stained B. burgdorferi without affecting bacterial viability or motility. Among the tick cell lines tested, the Rhipicephalus appendiculatus cell line RA243 achieved the highest percentage of association/internalization, with both high (90%) and low (10%) concentrations of BSK-H medium in tick cell culture medium. Treatment with cytochalasin D dramatically reduced the average percentage of cells with internalized spirochetes, which passed through a dramatic morphological change during their internalization by the host cell as observed in time-lapse photography. Almost all of the fluorescent bacteria were seen to be inside the tick cells. PKH labeling of borreliae proved to be a reliable and valuable tool to analyze the association of spirochetes with host cells by flow cytometry, confocal and fluorescence microscopy.


Assuntos
Borrelia burgdorferi , Coloração e Rotulagem/métodos , Carrapatos/citologia , Carrapatos/microbiologia , Animais , Borrelia burgdorferi/isolamento & purificação , Linhagem Celular , Células Cultivadas , Meios de Cultura , Citometria de Fluxo/métodos , Corantes Fluorescentes , Microscopia Confocal/métodos , Compostos Orgânicos , Fagocitose , Reprodutibilidade dos Testes , Spirochaetales/isolamento & purificação , Doenças Transmitidas por Carrapatos/microbiologia , Fatores de Tempo
11.
Braz. j. med. biol. res ; 49(7): e5211, 2016. tab, graf
Artigo em Inglês | LILACS | ID: lil-785057

RESUMO

This study aimed to describe the association of Borrelia burgdorferi s.s. with ixodid tick cell lines by flow cytometry and fluorescence and confocal microscopy. Spirochetes were stained with a fluorescent membrane marker (PKH67 or PKH26), inoculated into 8 different tick cell lines and incubated at 30°C for 24 h. PKH efficiently stained B. burgdorferi without affecting bacterial viability or motility. Among the tick cell lines tested, the Rhipicephalus appendiculatus cell line RA243 achieved the highest percentage of association/internalization, with both high (90%) and low (10%) concentrations of BSK-H medium in tick cell culture medium. Treatment with cytochalasin D dramatically reduced the average percentage of cells with internalized spirochetes, which passed through a dramatic morphological change during their internalization by the host cell as observed in time-lapse photography. Almost all of the fluorescent bacteria were seen to be inside the tick cells. PKH labeling of borreliae proved to be a reliable and valuable tool to analyze the association of spirochetes with host cells by flow cytometry, confocal and fluorescence microscopy.


Assuntos
Animais , Borrelia burgdorferi , Coloração e Rotulagem/métodos , Carrapatos/citologia , Carrapatos/microbiologia , Borrelia burgdorferi/isolamento & purificação , Linhagem Celular , Células Cultivadas , Meios de Cultura , Citometria de Fluxo/métodos , Corantes Fluorescentes , Microscopia Confocal/métodos , Compostos Orgânicos , Fagocitose , Reprodutibilidade dos Testes , Spirochaetales/isolamento & purificação , Doenças Transmitidas por Carrapatos/microbiologia , Fatores de Tempo
12.
Arq. Inst. Biol ; 80(2): 237-241, 20130000.
Artigo em Inglês | LILACS, VETINDEX | ID: biblio-1462232

RESUMO

This work evaluated the in vitro effects of Steinernema glaseri on the biology of engorged Amblyomma cajennense nymphs. The ticks were exposed to infective juveniles (IJs) of S. glaseri at different concentrations. Each treatment was composed by 10 experimental units (EU = repetitions) in Petri dishes maintained at 27 ± 1º C and relative humidity (RH) > 80 ± 10% for 72 hours. Then the nymphs were transferred to Petri dishes free of nematodes for observation of the following parameters: pre-ecdysis period (PEP), ecdysis period (EP), molting period (MP), ecdysis percentage (%Ec) and mortality percentage (%Mt). The groups treated with 5,000 and 10,000 IJs/EU showed significant alterations in the PEP when compared to the control, while for the EP only the treatment with 10,000 IJs/EU produced any significant changes compared to the control. The MP did not differ significantly from the control in any of the treated groups. For the %Ec only the group treated with 10,000 IJs/EU differed significantly from the control. The greatest efficiency was obtained at the concentration of 10,000 IJs/EU, in which the mortality percentage was 13%. This demonstrates that the nematode utilized was not able to cause high mortality in engorged A. cajennense nymphs and agrees with other reports indicating that immature ticks are not highly susceptible to entomopathogenic nematodes.


Esse trabalho avaliou os efeitos in vitro de Steinernema glaseri sobre a biologia de ninfas ingurgitadas de Amblyomma cajennense. Os carrapatos foram expostos a juvenis infectantes (JI) de S. glaseri sob diferentes concentrações. Cada tratamento foi composto de 10 unidades experimentais (EU = repetições) em placas de Petri mantidas sob 27 ± 1º C e UR > 80 ± 10% por 72 horas. Em seguida, as ninfas foram transferidas para placas de Petri isentas de nematoides para observação dos seguintes parâmetros: período de pré-ecdise (PPE), período de ecdise (PE), período de muda (PM), porcentagem de ecdise (%Ec) e porcentagem de mortalidade (%Mt). Os grupos tratados com 5.000 e 10.000 JI/UE mostraram alterações significativas no PPE quando comparados com o controle, enquanto para o PE somente o tratamento com 10.000 JI/UE produziu mudanças significativas quando comparado com o controle. Não houve diferença significativa do PM em relação ao grupo controle em nenhum dos tratamentos e, para a %Ec, somente o grupo tratado com 10.000 JI/UE diferiu significativamente do controle. A maior eficiência foi obtida com a concentração de 10.000 JI/EU na qual a mortalidade foi de 13%. Isso demonstra que o nematoide utilizado não foi capaz de causar alta mortalidade em ninfas ingurgitadas de A. cajennese e concorda com outros relatos indicando que carrapatos imaturos não são altamente susceptíveis a nematoides entomopatogênicos.


Assuntos
Carrapatos , Nematoides , Controle de Ácaros e Carrapatos
13.
Philos Trans A Math Phys Eng Sci ; 369(1953): 4064-77, 2011 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-21930565

RESUMO

It is now recognized that the International System of Units (SI units) will be redefined in terms of fundamental constants, even if the date when this will occur is still under debate. Actually, the best estimate of fundamental constant values is given by a least-squares adjustment, carried out under the auspices of the Committee on Data for Science and Technology (CODATA) Task Group on Fundamental Constants. This adjustment provides a significant measure of the correctness and overall consistency of the basic theories and experimental methods of physics using the values of the constants obtained from widely differing experiments. The physical theories that underlie this adjustment are assumed to be valid, such as quantum electrodynamics (QED). Testing QED, one of the most precise theories is the aim of many accurate experiments. The calculations and the corresponding experiments can be carried out either on a boundless system, such as the electron magnetic moment anomaly, or on a bound system, such as atomic hydrogen. The value of fundamental constants can be deduced from the comparison of theory and experiment. For example, using QED calculations, the value of the fine structure constant given by the CODATA is mainly inferred from the measurement of the electron magnetic moment anomaly carried out by Gabrielse's group. (Hanneke et al. 2008 Phys. Rev. Lett. 100, 120801) The value of the Rydberg constant is known from two-photon spectroscopy of hydrogen combined with accurate theoretical quantities. The Rydberg constant, determined by the comparison of theory and experiment using atomic hydrogen, is known with a relative uncertainty of 6.6×10(-12). It is one of the most accurate fundamental constants to date. A careful analysis shows that knowledge of the electrical size of the proton is nowadays a limitation in this comparison. The aim of muonic hydrogen spectroscopy was to obtain an accurate value of the proton charge radius. However, the value deduced from this experiment contradicts other less accurate determinations. This problem is known as the proton radius puzzle. This new determination of the proton radius may affect the value of the Rydberg constant . This constant is related to many fundamental constants; in particular, links the two possible ways proposed for the redefinition of the kilogram, the Avogadro constant N(A) and the Planck constant h. However, the current relative uncertainty on the experimental determinations of N(A) or h is three orders of magnitude larger than the 'possible' shift of the Rydberg constant, which may be shown by the new value of the size of the proton radius determined from muonic hydrogen. The proton radius puzzle will not interfere in the redefinition of the kilogram. After a short introduction to the properties of the proton, we will describe the muonic hydrogen experiment. There is intense theoretical activity as a result of our observation. A brief summary of possible theoretical explanations at the date of writing of the paper will be given. The contribution of the proton radius puzzle to the redefinition of SI-based units will then be examined.

14.
Braz J Med Biol Res ; 43(3): 297-302, 2010 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-20209376

RESUMO

Patients with metabolic syndrome are at high-risk for development of atherosclerosis and cardiovascular events. The objective of this study was to examine the major determinants of coronary disease severity, including those coronary risk factors associated with metabolic syndrome, during the early period after an acute coronary episode. We tested the hypothesis that inflammatory markers, especially highly sensitive C-reactive protein (hsCRP), are related to coronary atherosclerosis, in addition to traditional coronary risk factors. Subjects of both genders aged 30 to 75 years (N = 116) were prospectively included if they had suffered a recent acute coronary syndrome (acute myocardial infarction or unstable angina pectoris requiring hospitalization) and if they had metabolic syndrome diagnosed according to the National Cholesterol Education Program/Adult Treatment Panel III. Patients were submitted to a coronary angiography and the burden of atherosclerosis was estimated by the Gensini score. The severity of coronary disease was correlated (Spearman's or Pearson's coefficient) with gender (r = 0.291, P = 0.008), age (r = 0.218, P = 0.048), hsCRP (r = 0.256, P = 0.020), ApoB/ApoA ratio (r = 0.233, P = 0.041), and carotid intima-media thickness (r = 0.236, P = 0.041). After multiple linear regression, only male gender (P = 0.046) and hsCRP (P = 0.012) remained independently associated with the Gensini score. In this high-risk population, male gender and high levels of hsCRP, two variables that can be easily obtained, were associated with more extensive coronary disease, identifying patients with the highest potential of developing new coronary events.


Assuntos
Síndrome Coronariana Aguda/sangue , Proteína C-Reativa/metabolismo , Síndrome Metabólica/sangue , Índice de Gravidade de Doença , Síndrome Coronariana Aguda/etiologia , Adulto , Idoso , Biomarcadores/sangue , Angiografia Coronária , Feminino , Humanos , Masculino , Síndrome Metabólica/complicações , Pessoa de Meia-Idade , Estudos Prospectivos , Fatores de Risco , Sensibilidade e Especificidade , Fatores Sexuais
15.
Braz. j. med. biol. res ; 43(3): 297-302, Mar. 2010. tab
Artigo em Inglês | LILACS | ID: lil-539717

RESUMO

Patients with metabolic syndrome are at high-risk for development of atherosclerosis and cardiovascular events. The objective of this study was to examine the major determinants of coronary disease severity, including those coronary risk factors associated with metabolic syndrome, during the early period after an acute coronary episode. We tested the hypothesis that inflammatory markers, especially highly sensitive C-reactive protein (hsCRP), are related to coronary atherosclerosis, in addition to traditional coronary risk factors. Subjects of both genders aged 30 to 75 years (N = 116) were prospectively included if they had suffered a recent acute coronary syndrome (acute myocardial infarction or unstable angina pectoris requiring hospitalization) and if they had metabolic syndrome diagnosed according to the National Cholesterol Education Program/Adult Treatment Panel III. Patients were submitted to a coronary angiography and the burden of atherosclerosis was estimated by the Gensini score. The severity of coronary disease was correlated (Spearman’s or Pearson’s coefficient) with gender (r = 0.291, P = 0.008), age (r = 0.218, P = 0.048), hsCRP (r = 0.256, P = 0.020), ApoB/ApoA ratio (r = 0.233, P = 0.041), and carotid intima-media thickness (r = 0.236, P = 0.041). After multiple linear regression, only male gender (P = 0.046) and hsCRP (P = 0.012) remained independently associated with the Gensini score. In this high-risk population, male gender and high levels of hsCRP, two variables that can be easily obtained, were associated with more extensive coronary disease, identifying patients with the highest potential of developing new coronary events.


Assuntos
Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Síndrome Coronariana Aguda/sangue , Proteína C-Reativa/metabolismo , Síndrome Metabólica/sangue , Índice de Gravidade de Doença , Síndrome Coronariana Aguda/etiologia , Biomarcadores/sangue , Angiografia Coronária , Síndrome Metabólica/complicações , Estudos Prospectivos , Fatores de Risco , Sensibilidade e Especificidade , Fatores Sexuais
17.
J. venom. anim. toxins incl. trop. dis ; 14(3): 533-540, 2008. ilus
Artigo em Inglês | LILACS | ID: lil-492215

RESUMO

Leptospirosis is a public health problem worldwide and its etiology remains unclear. Its pathogenesis involves a complex interaction between host and infecting microorganism. The inflammatory reaction that controls the infection process also underscores many pathophysiological events occurring in leptospirosis. We investigated the presence of tumor necrosis factor-alfa (TNF-alfa) and interleukin-6 (IL-6) in renal tissues by immunohistochemical and histopathological examination in animals experimentally inoculated with Leptospira serovar Canicola. All the tests were carried out 2, 7, 14, 21 or 28 days after inoculation. Although TNF-alfa and IL-6 had been detected in tissues throughout the observation period, these cytokines appeared more intensely during the initial phase of infection. Therefore, both TNF-alfa and IL-6 were associated with the immunopathogenesis of leptospirosis. This profile suggests a high immunocellular response throughout the early infection stages followed by subsequent humoral response.


Assuntos
Animais , Camundongos , Leptospirose/diagnóstico , Leptospirose/fisiopatologia , Fator de Necrose Tumoral alfa , Camundongos Endogâmicos BALB C/imunologia
19.
Arch Insect Biochem Physiol ; 55(4): 178-87, 2004 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-15027072

RESUMO

The participation of eicosanoids and second messengers in the regulation of endocytosis by the ovaries was investigated using the uptake of Rhodnius heme binding protein (RHBP) as an experimental model. The rate of RHBP uptake decreased up to 40% in the presence of BWA4C and NDGA, 5 and 12-lipoxygenase inhibitors, respectively, suggesting the involvement of lipoxygenase products in endocytosis regulation. Addition of Leukotriene B4 (LTB(4); one product of the 5 lipoxygenase pathway) increased in vitro the uptake of RHBP by 30%. The content of cAMP in the Rhodnius' ovaries were monitored after treatment with different eicosanoids and inhibitors of eicosanoids synthesis. The amount of cAMP decreased in the presence of indomethacin (by 50%), while treatment with PGE(2) induced an increase of 85% of this messenger in the ovaries. The presence of LTB(4) in the medium inhibited in 60% the content of cAMP in the ovaries, while BWA4C induced a 100% increase of this messenger in the ovaries. Addition of 1 microM DBcAMP in the medium resulted in a 30% decrease in the rate of RHBP uptake. Taken together, these data show that cyclooxygenase and lipoxygenase products participate in the control of protein internalization by modulation of cAMP levels.


Assuntos
Proteínas de Transporte/metabolismo , AMP Cíclico/metabolismo , Proteínas do Ovo/metabolismo , Endocitose/fisiologia , Hemeproteínas/metabolismo , Lipoxigenase/metabolismo , Ovário/metabolismo , Rhodnius/metabolismo , Animais , Eicosanoides/fisiologia , Inibidores Enzimáticos/farmacologia , Feminino , Proteínas Ligantes de Grupo Heme , Lipoxigenase/efeitos dos fármacos , Modelos Biológicos , Sistemas do Segundo Mensageiro
20.
Braz. j. med. biol. res ; 36(5): 677-682, May 2003. tab
Artigo em Inglês | LILACS | ID: lil-331450

RESUMO

We investigated whether stress interferes with fertility during adulthood. Male Wistar rats (weighing 220 g in the beginning of the experiment) were forced to swim for 3 min in water at 32ºC daily for 15 days. Stress was assessed by the hot-plate test after the last stressing session. To assess fertility, control and stressed males (N = 15 per group) were mated with sexually mature normal females. Males were sacrificed after copulation. Stress caused by forced swimming was demonstrated by a significant increase in the latency of the pain response in the hot-plate test (14.6 ± 1.25 s for control males vs 26.0 ± 1.53 s for stressed males, P = 0.0004). No changes were observed in body weight, testicular weight, seminal vesicle weight, ventral prostate weight or gross histological features of the testes of stressed males. Similarly, no changes were observed in fertility rate, measured by counting live fetuses in the uterus of normal females mated with control and stressed males; no dead or incompletely developed fetuses were observed in the uterus of either group. In contrast, there was a statistically significant decrease in spermatid production demonstrated by histometric evaluation (154.96 ± 5.41 vs 127.02 ± 3.95 spermatids per tubular section for control and stressed rats, respectively, P = 0.001). These data demonstrate that 15 days of forced swimming stress applied to adult male rats did not impair fertility, but significantly decreased spermatid production. This suggests that the effect of stress on fertility should not be assessed before at least the time required for one cycle of spermatogenesis


Assuntos
Animais , Masculino , Feminino , Ratos , Fertilidade , Espermátides , Espermatogênese , Estresse Fisiológico , Natação , Peso Corporal , Tamanho do Órgão , Próstata , Ratos Wistar , Glândulas Seminais , Contagem de Espermatozoides , Testículo
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