Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 15 de 15
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
Intervalo de ano de publicação
1.
BMC Public Health ; 23(1): 302, 2023 02 10.
Artigo em Inglês | MEDLINE | ID: mdl-36765300

RESUMO

BACKGROUND: Swimming pools are places for practicing sports, recreation, relaxation, and socialization. However, swimming pools can expose swimmers to physicochemical and microbiological risks. Accordingly, we studied the environmental health aspects and microbial infections for such recreational water aiming to disclose the possible risks they pose on swimmers. METHODS: 26 pools in Alexandria, Egypt were checked for water quality; 13 pools were checked in winter then summer, and other 13 pools were checked in summer only. Water was collected from both the top and the bottom of each pool; a total of 78 samples were collected in sterile containers. Each sample was divided into three parts; the first part was used for assessing the bacteriological quality of water. They were tested for total colony count (TCC), total coliform (TC), fecal coliform, and E. coli. The second part was used for chemical analysis. The third part was checked for parasitological study. RESULTS: Obtained data showed that only 7.7%, 78.2%, and 100% of the examined water samples have been found to fulfill the Egyptian standards for TCC, TC, and E. coli, respectively. Moreover, parasitic infection (PI) was noticed in 73.1% of the collected water samples; mainly Cyclospra and Isospora (37.2% each), followed by Cryptosporidium spp., Giradia lamblia, Microsporidia spp., and Blastocystis spp. (34.6%, 21.8%, 15.4%, and 14.1%, respectively). Acanthameba spp. was detected but at a lower rate (5.1%). The frequency of cleaning the swimming pools, flow rate, Cl2, and total dissolved solids are significantly affected PI, independently. CONCLUSION: The tested water samples don't meet Egyptian bacteriological criteria. High parasitic contamination despite high residual chlorine level mainly intestinal coccidia, G. lamblia, microsporidia, and Blastocystis spp. Thus, monitoring pool's water quality and improving the disinfection system are mandatory. Consequently, Health education regarding hygienic behaviors before and during swimming should be included in governmental programs.


Assuntos
Criptosporidiose , Cryptosporidium , Piscinas , Humanos , Escherichia coli , Microbiologia da Água , Bactérias Gram-Negativas , Saúde Ambiental , Cloro/análise , Natação
2.
Scand J Infect Dis ; 46(7): 508-14, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24832854

RESUMO

BACKGROUND: Hepatitis C virus (HCV) is associated with fibrosis, cirrhosis, hepatocellular carcinoma (HCC), and end-stage liver disease. In the normal liver, fibronectin plays crucial roles in various cellular functions, including cell adhesion, migration, proliferation, and differentiation. Increased expression of fibronectin is associated with areas of physiological or pathological tissue remodeling, including wound healing and tissue repair. The aim of the current study was to correlate the cellular fibronectin expression level in peripheral blood fibrocytes of chronic HCV patients with the severity of liver fibrosis as detected by liver biopsy. METHODS: The present study was conducted on 20 fibrotic liver cases with detectable HCV RNA, 10 HCV cirrhotic liver cases, and 10 control subjects of matched age and sex. Cellular fibronectin RNA was detected by PCR. RESULTS: The mean level of cellular fibronectin expression in cases with liver fibrosis was significantly higher than the corresponding level in cases with liver cirrhosis (p = 0.019). Control individuals did not express cellular fibronectin. There was also a significant correlation between the Metavir score and cellular fibronectin RNA, APRI, and FIB-4 scores. However, based on the area under the curve (AUC) values, cellular fibronectin showed a lower diagnostic performance than APRI and FIB-4 scores. CONCLUSIONS: Cellular fibronectin RNA showed satisfactory reproducibility and could be used to differentiate HCV fibrotic liver (F1-F3) and HCV cirrhotic liver (F4) from normal liver (F0).


Assuntos
Fibronectinas/metabolismo , Hepatite C Crônica/metabolismo , Cirrose Hepática/metabolismo , Adulto , Área Sob a Curva , Biomarcadores/metabolismo , Células Cultivadas , Feminino , Hepatite C Crônica/complicações , Hepatite C Crônica/patologia , Humanos , Leucócitos Mononucleares/metabolismo , Fígado/metabolismo , Fígado/patologia , Cirrose Hepática/diagnóstico , Cirrose Hepática/virologia , Masculino , Pessoa de Meia-Idade , Curva ROC
3.
Sci Rep ; 13(1): 3815, 2023 03 07.
Artigo em Inglês | MEDLINE | ID: mdl-36882428

RESUMO

Cancer's etiology is linked to oxidative stress. As a result, it's vital to find effective natural antioxidant remedies. Salix mucronata and Triticum spelta plant extracts were prepared using five different solvents and examined for their cytotoxicity against liver HepG2 cancer cell line. It was found that Salix mucronata ethanolic extract is high in antioxidant mediated anti-cancer activity. The functional constituents (phenolic and flavonoids) as well as preparation of different ethanolic concentrations used to study their properties that include DPPH, oxygen, hydroxyl, nitrogen radical scavenging activities, ferric reducing power and metal chelating activities. The MTT assay was used to determine antioxidant-mediated anti-cancer activity against human liver (HepG2) and colorectal (Caco-2) cancer cells to calculate the half-maximal growth inhibitory concentration (IC50). Moreover, flow cytometry analysis was used to quantify the apoptotic effect on the treated cancer cells. Additionally, qRTPCR of p53, BCL2, Cyclin D, MMP9 and VEGF were measured. Furthermore, HPLC was used to assess the most effective ingredients of the plant extract. Salix mucronata 50% ethanol extract had the highest polyphenolic content, anti-oxidant, and anti-proliferative activity. Salix mucronata increased the number of total apoptotic cells, and caused an upregulation of p53 gene expression by more than five folds and a downregulation of gene expression level of BCL2, Cyclin D, MMP9 and VEGF by more than five folds. Consequently, that could modulate oxidative stress and improve the effectiveness of cancer therapy. Results, also, showed that Triticum spelta ethanolic extract was less effective than Salix mucronata. Therefore, Salix mucronata ethanolic extract represents promising surrogate natural therapy for apoptosis-mediated cancer and recommended for further investigation using animal model.


Assuntos
Neoplasias Colorretais , Extratos Vegetais , Salix , Triticum , Humanos , Antioxidantes/farmacologia , Células CACO-2 , Neoplasias Colorretais/tratamento farmacológico , Ciclina D , Fígado , Metaloproteinase 9 da Matriz , Proteínas Proto-Oncogênicas c-bcl-2 , Proteína Supressora de Tumor p53 , Fator A de Crescimento do Endotélio Vascular , Extratos Vegetais/farmacologia
4.
Sci Rep ; 12(1): 22522, 2022 12 29.
Artigo em Inglês | MEDLINE | ID: mdl-36581674

RESUMO

The main attempt of this study is to isolate, determine potential probiotic properties and enzyme production of some lactic acid bacteria (LAB). Among all isolates, two LAB strains isolated from human mother milk and cottage cheese revealed antimicrobial activity against some tested pathogenic strains. Both isolates inhibited all the tested pathogens except Escherichia coli. The two isolates were identified by morphological, biochemical properties and then by 16S rRNA gene sequencing technique as Lactobacillus acidophilus SAM1 and Lactiplantibacillus plantarum SAM2. Potential probiotic characters were investigated. Both strains survived in relatively low pH and high bile concentrations and were able to grow at 0.5% of pancreatin concentrations. Their growth decreased by increasing phenol from 0.2% till 0.5%. Both strains did not show hemolytic activity. Coaggregation potential was exhibited by the two strains against Staphylococcus aureus and Candida albicans. Hydrophobicity of Lactobacillus acidophilus SAM1 and Lactiplantibacillus plantarum SAM2, with ethyl acetate; were 88.1% and 82.8%, respectively. Lactobacillus acidophilus SAM1 was susceptible to Ampicillin, Penicillin, Erythromycin, Ciprofloxacin and Tetracycline; on the contrary, it resists Vancomycin and Cefoxitin; while Lactiplantibacillus plantarum SAM2 resists all tested antibiotics. Maximum growth was achieved using glucose as a carbon source and yeast extract as nitrogen source for both strains; however, glucose is the most preferred carbon source for microorganisms and it prevents the uptake of carbon from other sources like yeast by catabolite repression mechanism. Lactobacillus acidophilus SAM1 produces lipase enzyme, while Lactiplantibacillus plantarum SAM2 produces amylase and protease.


Assuntos
Queijo , Lactobacillales , Probióticos , Feminino , Humanos , Lactobacillus/genética , Queijo/microbiologia , Mães , RNA Ribossômico 16S/genética , Lactobacillales/genética , Leite Humano , Escherichia coli/genética , Antibacterianos/farmacologia , Lactobacillus acidophilus , Probióticos/farmacologia , Glucose
5.
Environ Sci Pollut Res Int ; 28(23): 29629-29642, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33559824

RESUMO

Male infertility is considered one of the most critical health problems that are expected to expand worldwide. Ulva lactuca is a species of green seaweeds which is known to be a rich source of many important nutrients. Accordingly, this study is designated to investigate the therapeutic role of Ulva lactuca water fraction (UL) against monosodium glutamate (MSG)-induced male reproductive system disorders in male rats. Ulva lactuca methanolic crude extract was prepared firstly, and then water-dissolved compounds of this crude methanolic extract were separated. Ulva lactuca water fraction active phenolic compounds were determined using high-performance liquid chromatography (HPLC). Thirty-two male rats were divided equally into four groups; male infertility was induced in sixteen experimental animals by MSG at dose of 15 mg/Kg for 45 days. Eight infertile animals were treated with 100 mg/Kg of Ulva lactuca water fraction for 30 days. The rest of the animals were divided into two control groups; one control group (eight animals) was used to study the effect of UL on healthy rats at dose of 100 mg/Kg for 30 days and healthy control group (eight animals). Semen quality parameters (concentration and motility ratio), serum testosterone, prostate-specific antigen (PSA), and phosphatases were estimated by using standard protocols. Moreover, prooxidants and endogenous antioxidant enzymes were measured in prostate and testis homogenates. In addition, relative expression of pro-inflammatory genes (inducible nitric oxide synthase (i-NOS), cyclooxygenase-2 (COX-2), tumor necrosis factor-α alpha (TNF-α), and tumor protein (P53)) were assessed in testicular and prostatic tissues. Finally, histological alterations were measured by hematoxylin and eosin (H&E) stain. Results revealed that Ulva lactuca water fraction contains active phenolic constituents responsible for its antioxidant bioactivity. Oral administration of MSG significantly induced histological alterations. Oxidative stress was observed with elevated levels of nitric oxide (NO), thiobarbituric acid reactive substances (TBARS), and xanthine oxidase (XO) activity in both testis and prostate tissues. MSG adversely affected prostate function via elevation of PSA, prostatic acid phosphatases (PAPs), and total acid phosphatases (TAPs). In addition, it upregulated pro-inflammatory genes in testis and prostate tissues. Meanwhile, MSG reduced serum testosterone, semen quality, and antioxidant enzyme activities (glutathione peroxidase (GPx), glutathione-s-transferase (GST), and superoxide dismutase (SOD)). Treatment with UL notably ameliorated the state of oxidative stress and downregulated the expression of pro-inflammatory gene markers. This study highlighted the potential efficacy of Ulva lactuca water fraction on MSG-induced male infertility in rats. Therapeutic effect of UL on oxidative stress and inflammation induced by MSG in testicular and prostatic tissues.


Assuntos
Glutamato de Sódio , Ulva , Animais , Antioxidantes , Humanos , Masculino , Estresse Oxidativo , Próstata , Ratos , Análise do Sêmen , Testículo , Água
6.
Curr Rev Clin Exp Pharmacol ; 16(2): 139-154, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-32598269

RESUMO

BACKGROUND: Berberine (BBR), an isoquinoline alkaloid, acts as a multipotent active pharmaceutical ingredient to counteract several types of dementia based on its numerous pharmacological actions including antioxidant, anti-inflammatory, cholesterol-lowering effect, and inhibition of Aß production and AChE. However, BBR suffers from poor absorption, bioavailability and brain drug uptake. The present study is directed for the formulation and characterization of Chitosan BBR-Nanoparticles (BBR-NPs) as well as the estimation of its neuroprotective effects against scopolamine induced cognitive impairments. METHODS: BBR-NPs were formulated using the ionic gelation method, and tripolyphosphate was chosen as a crosslinker. Nanoparticles size, zeta potential, encapsulation efficiency and releasing profile were estimated. To investigate the neuroprotective effects, adult fifty-six Wistar male rats were randomly distributed into three control groups, received saline, polyethylene glycol or Chitosan- NPs, respectively; induced group, received scopolamine (2 mg/ kg, i.p.) and three treated groups were orally administrated BBR (50 mg/ kg), BBR- NP (7 mg/ kg) and donepezil (2.25 mg/ kg, as positive control) followed by scopolamine injection after 40 min, daily for 4 weeks. Morris water maze test, oxidative stress parameters, cholinergic and amyloid-ß processing intermediates, as well as neuroplasticity markers and histopathological examination were assessed. RESULTS: Our results showed that BBR- NPs were better than BBR and donepezil as BBR- NPs were powerful inhibitory ligands towards AChE and Aß42 formation and significantly down-regulated Tau, iNOS and BACE gene expression in rats' hippocampus. BBR-NPs administration, at 1/6 of BBR therapeutic recommended dose, significantly improved learning and memory function. This could be accredited to the diminution of oxidative stress and amyloid-ß toxicity in addition to the improvement of the neuroplasticity markers. CONCLUSION: The enhancing effect of BBR- NPs could be related to the enhancing of its bioavailability, absorption and brain drug uptake, which need more investigation in future work.


Assuntos
Doença de Alzheimer , Berberina , Fármacos Neuroprotetores , Doença de Alzheimer/induzido quimicamente , Peptídeos beta-Amiloides/metabolismo , Animais , Berberina/farmacologia , Masculino , Fármacos Neuroprotetores/farmacologia , Ratos , Ratos Wistar
7.
Biotechnol Rep (Amst) ; 28: e00536, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33088732

RESUMO

Leaves of fig, guava, olive and pomegranate and peels of ripe pomegranate fruits were mechanically pressed to obtain the crude juices. The resultant crude juices were subjected to the estimation of certain phytochemicals, i.e. total phenols, flavonoids, tannins and anthocyanins by HPLC. The assessment of their antioxidant activities were performed by three methods, i.e. DPPH, reducing power and metal chelating assays. The results indicated that the amounts of polyphenols, flavonoids, tannins and anthocyanins in crude pomegranate peels juices were markedly higher than those of other medicinal plants crude juices. The polyphenolic constituents in fig leaves, pomegranate leaves and peels, guava leaves and olive leaves were distinguished using HPLC. The major compounds found in all crude juices were gallic acid, ellagic acid, naringenin, ferulic acid and methyl gallate, respectively. Pomegranate peels crude juice exhibited the highest antioxidant activity assessed by the aforementioned methods in comparison with other medicinal plants crude juices.

9.
J Health Pollut ; 8(18): 180608, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30524857

RESUMO

BACKGROUND: Metals pollution plays an important role in the regulation of gene expression through interference with signal transduction pathways which are important for cell bioactivity. OBJECTIVES: The present study was conducted to estimate metallothionein levels in mussels as a biomarker of exposure to heavy metals in order to monitor the pollution of Abu Qir Bay, Egypt (El-Maadiya region) and to evaluate the impact of heavy metals on human health by examining insulin-like growth factor II (IGF-2) gene expression in peripheral blood mononuclear cells. METHODS: One hundred and forty mussel samples (Andara dulofii) were collected from Abu-Qir Bay, stored in bags, preserved in an ice box, and then transported to the laboratory to acclimatize at 20°C for three days in ethylene diamine tetra acetic acid (EDTA)-free synthetic sea water to determine the presence of metallothionein and five other metals (cadmium (Cd), lead (Pb), chromium (Cr), copper (Cu) and zinc (Zn)). RESULTS: Results showed that mussels collected from the study area contained a measurable amount of metallothionein. In addition, results revealed an increased level of malondialdehyde coinciding with a decreased level of antioxidants, leading to oxidative stress in local fishermen. CONCLUSIONS: The present data demonstrated a significant increase in the gene expression of IGF-2 and a positive correlation between IGF-2 gene expression and the enzymatic activity of glutathione peroxidase in male subjects. PARTICIPANT CONSENT: Obtained. ETHICS APPROVAL: Written consent was provided by the study participants and study approval was given by the ethics committee of Alexandria University (US Department of Health and Human Services, Registration of an Institutional Review Board, IORG0008812 Medical Research Institute, Expires 4/8/2019, OMB No:0990-0279). COMPETING INTERESTS: The authors declare no competing financial interests.

10.
Diagn Microbiol Infect Dis ; 58(4): 419-26, 2007 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-17509806

RESUMO

GRA2 is a highly immunogenic protein secreted from the dense granules of Toxoplasma gondii. Recent success in purifying full-length, soluble GRA2 from bacteria as a thioredoxin (TRX)-(Hisx6) fusion protein led to investigate the antigenicity of the recombinant protein against human sera. On immunoblots, TRX-(Hisx6)-GRA2 was recognized by sera collected in Iran from T. gondii-infected pregnant women. An IgG enzyme-linked immunosorbent assay was developed to evaluate the reactivity of sera, collected from pregnant women both in France and Iran, to the TRX-(Hisx6)-GRA2 fusion protein. Specificity of the test was 96.4%. Sensitivity of the GRA2 enzyme-linked immunosorbent assay ranged from 95.8% (sera collected in France) to 100% (sera collected in Iran) for sera of acute infection and from 65.7% (sera collected in France) to 71.4% (sera collected in Iran) for sera of chronic infection. The recombinant GRA2 could thus advantageously complement previously described T. gondii antigens for the serodiagnosis of acute Toxoplasma infection.


Assuntos
Anticorpos Antiprotozoários/sangue , Antígenos de Protozoários , Ensaio de Imunoadsorção Enzimática/métodos , Proteínas de Protozoários , Proteínas Recombinantes de Fusão , Toxoplasmose/diagnóstico , Animais , Antígenos de Protozoários/genética , Antígenos de Protozoários/isolamento & purificação , França , Humanos , Imunoglobulina G/sangue , Irã (Geográfico) , Gestantes , Proteínas de Protozoários/genética , Proteínas de Protozoários/isolamento & purificação , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/isolamento & purificação , Sensibilidade e Especificidade , Testes Sorológicos/métodos , Toxoplasma/imunologia
11.
Exp Toxicol Pathol ; 69(5): 285-291, 2017 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-28190563

RESUMO

Aflatoxin contamination of animal diet has adverse effects on animal health and productivity. This study was performed to investigate the effect of using coumarin and/or chlorophyllin in rat diet against aflatoxicosis. Fifty-four rats were assigned into 7 groups (6 rats each). G1 was a negative control. G2 received water with coumarin 0.5%. G3 received water with chlorophyllin 0.5%. G4 received water with coumarin 0.5% and chlorophyllin 0.5%. G5-8 fed aflatoxin B1 1000ppb in diet. Group 6-8 were administered similar treatments as G2-4. The experiment ended after 8 weeks. Random glucose, total lipid, total cholesterol, total triglycerides, total protein, serum ALT, AST, creatinine, and urea were measured. Histopathology of liver, kidney and pancreas and immunohistochemical staining of placental glutathione-S-transferase (GST-P) in liver were performed. The glucose serum level, cholesterol, AST, and ALT were elevated in G5 compared to G6-8. The liver and kidney lesions in G5 included vacuolation and necrosis which subsided in G6-8. The necrosis and inflammatory cells infiltration in the pancreas of G5 were absent in G6-8. GST-P positive hepatocytes were abundant in G5, few in G6 and absent in G7 and G8. In conclusion, the chlorophyllin and coumarin possessed protective and anti-carcinogenic effect against aflatoxicosis in rats.


Assuntos
Aflatoxina B1/toxicidade , Clorofilídeos/farmacologia , Cumarínicos/farmacologia , Ração Animal , Animais , Contaminação de Alimentos , Masculino , Distribuição Aleatória , Ratos , Ratos Sprague-Dawley
12.
Open Microbiol J ; 9: 136-40, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26464613

RESUMO

BACKGROUND: In chronic HCV infection, pathological accumulation of the extracellular matrix is the main feature of liver fibrosis; that indicates the imbalanced rate of increased matrix synthesis to decreased breakdown of connective tissue proteins. Matrix metalloproteinases (MMPs) play a crucial role in remodeling of extracellular matrix. It is known that expression of MMPs is regulated by Tumor necrosis factor (TNF)-α. Also, levels of TNF-α in liver and serum are increased in chronic HCV patient. Accordingly, this study aimed to correlate the plasma levels of MMP-2, MMP-9 and TNF-α in chronic HCV patients with the pathogenesis of the liver. METHODS: The current study was conducted on 15 fibrotic liver cases with detectable HCV RNA, 10 HCV cirrhotic liver cases, and 15 control subjects of matched age and sex. Plasma MMP-2, MMP-9 and TNF-α were measured by ELISA. RESULTS: Data revealed that the MMP2, MMP9 and TNF-α levels showed a significant elevation in chronic HCV patients compared to control group (p= 0.001). But, no significant correlation was observed in levels of MMP-2, MMP-9, and TNF-α between fibrotic and cirrhotic cases. CONCLUSIONS: MMP-2, MMP-9 and TNF-α showed high reproducibility to differentiate chronic HCV patients from control group. On the contrary, MMP-2, MMP-9 and TNF-α were not able to differentiate fibrotic from cirrhotic liver cases. Thus, MMP-2, MMP-9 and TNF-α could not be correlated with the progression of liver disease. Rather they could be used as prognostic markers of liver fibrosis.

13.
Am J Trop Med Hyg ; 71(2): 179-86, 2004 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-15306707

RESUMO

We used a pool of recombinant rifin proteins to pre-adsorb antibodies to rifin in the plasma of semi-immune African (Gabonese) adults and showed that this results in a reduction in the level of IgG antibody reactivity to variant surface antigens (VSA) measured in a standardized flow cytometric assay with a panel of heterologous parasite isolates. The same methods demonstrated a similar but less-marked contribution of antibodies to the duffy binding-like 1alpha (DBL-1alpha ) domain to the overall anti-VSA response. Thus, we conclude that both antibodies to rifin and, to a lesser extent, antibodies directed to conserved regions of the Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) DBL-1alpha domain contribute to the overall antibody response to VSA. We also assessed the associations between these different antibody responses in a cohort of Gabonese children. We found marked differences related to the childrens' history of presentation with either mild or severe malaria, but no consistent pattern that would indicate a specific role or influence of antibody responses to rifin.


Assuntos
Anticorpos Antiprotozoários/sangue , Antígenos de Protozoários/imunologia , Antígenos de Superfície/imunologia , Eritrócitos/parasitologia , Plasmodium falciparum/imunologia , Proteínas de Protozoários/imunologia , Adulto , Sequência de Aminoácidos , Animais , Anticorpos Antiprotozoários/imunologia , Especificidade de Anticorpos , Antígenos de Protozoários/química , Antígenos de Superfície/química , Criança , Citometria de Fluxo , Gabão , Humanos , Malária Falciparum/parasitologia , Dados de Sequência Molecular , Proteínas de Protozoários/genética , Proteínas Recombinantes/imunologia
14.
Infect Immun ; 71(11): 6229-33, 2003 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-14573641

RESUMO

Plasmodium falciparum rifin proteins, belonging to the largest known family of variable infected-erythrocyte surface-expressed proteins encoded by rif genes, were recently shown to be capable of inducing a strong immune response in P. falciparum-infected adults living in an area in Gabon where malaria is endemic. In the present study, the levels of antirifin antibodies were analyzed in serum obtained from 60 children from the same area who were admitted to hospital and diagnosed with severe malaria. High antirifin antibody concentrations in these individuals correlated significantly with their capacity to rapidly clear their parasites from the circulation after the start of chemotherapy. A doubling of antirifin antibody concentrations reduced the clearance time by 5 h (95% confidence interval, 4.1 to 6.9 h). In the same group of children, who were followed up for 2 years, antirifin antibody levels did not correlate with a reduced rate of reinfection or with a delay in the time to the first reinfection. However, the initial antirifin antibody levels were sustained over the study period. The likelihood that these antibodies could confer a certain degree of protection against malaria is supported by our findings of statistically higher levels of antirifin antibodies to all four rifin proteins in a group of 42 asymptomatic parasitemic children.


Assuntos
Anticorpos Antiprotozoários/sangue , Malária Falciparum/imunologia , Plasmodium falciparum/imunologia , Proteínas de Protozoários/imunologia , Fatores Etários , Animais , Criança , Pré-Escolar , Eritrócitos/imunologia , Seguimentos , Humanos , Lactente
15.
Infect Immun ; 70(12): 7013-21, 2002 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-12438381

RESUMO

Antibodies from individuals living in areas where malaria is endemic are known to react with parasite-derived erythrocyte surface proteins. The major immunogenic and clonally variant surface antigen described to date is Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP-1), which is encoded by members of the multicopy var gene family. We report here that rifin proteins (RIF proteins), belonging to the largest known family of variable infected erythrocyte surface-expressed proteins, are also naturally immunogenic. Recombinant RIF proteins were used to analyze the antibody responses of individuals living in an area of intense malaria transmission. Elevated anti-rifin antibody levels were detected in the majority of the adult population tested, whereas the prevalence of such antibodies was much lower in malaria-exposed children. Despite the high degree of diversity between rif sequences and the high gene copy number, it appears that P. falciparum infections can induce antibodies that cross-react with several variant rifin molecules in many parasite isolates in a given community, and the immune response is most likely to be stable over time in a hyperendemic area. The protein was localized by fluorescence microscopy on the membrane of ring and young trophozoite-infected erythrocytes with antibodies from human immune sera with specificities for recombinant RIF protein.


Assuntos
Variação Antigênica , Antígenos de Protozoários/imunologia , Plasmodium falciparum/imunologia , Proteínas de Protozoários/imunologia , Adolescente , Adulto , Sequência de Aminoácidos , Animais , Anticorpos Antiprotozoários/sangue , Anticorpos Antiprotozoários/imunologia , Antígenos de Protozoários/genética , Criança , Pré-Escolar , Estudos de Coortes , Estudos Transversais , Eritrócitos/metabolismo , Eritrócitos/parasitologia , Humanos , Lactente , Malária Falciparum/imunologia , Malária Falciparum/parasitologia , Pessoa de Meia-Idade , Dados de Sequência Molecular , Proteínas de Protozoários/genética , Proteínas Recombinantes/imunologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA