Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 9 de 9
Filtrar
Más filtros










Base de datos
Intervalo de año de publicación
1.
J Nanosci Nanotechnol ; 13(6): 4056-65, 2013 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-23862448

RESUMEN

In this paper, Mg0.5Zn0.5-Cu(x)Fe2O4 ferrites nanoparticles were synthesized by facile co-precipitation route and characterized in detail in terms of their structural, electrical and magnetic properties as a function of Cu concentration. The prepared samples have cubic spinel phase as confirmed by X-ray diffraction patterns. The decrease of the lattice constant and increase of X-ray density indicate the solubility of Cu ions in the spinel lattice. The AC conductivity measurements between 300 K and 773 K at different frequencies 1 KHz up to 1 MHz, showed two different behaviors as semiconductor-like at high temperature and frequency depending behavior associated with dispersion phenomena at low temperatures. The conduction mechanism in the system is influenced by Cu concentration and the dominant one is the hopping conduction mechanism. Dielectric measurements at the same conditions of temperatures and frequencies exhibited that the dielectric loss increases with increasing the temperature and decreasing the frequency indicating the semiconducting nature of the ferrite compounds. An anomalous behavior of the dielectric loss is observed in samples with high Cu content which explained in terms of resonance between frequency accompanied the electronic hopping and the frequency of the external electric field. The analysis of Mössbauer spectra revealed that copper free compound is super-paramagnetically relaxed in nature and zinc free compound demonstrates ferrimagnetic order. Moreover, hyperfine field spectrum shows the migration of Cu ions from octahedral to tetrahedral site in zinc free compound.

2.
J Egypt Soc Parasitol ; 39(2): 503-10, 2009 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-19795757

RESUMEN

The development of chloroquine as an antimalarial drug and the subsequent evolution of drug resistant Plasmodium strains had major impacts on global public health in the 20th century. In P. falciparum, the cause of the most lethal human malaria, chloroquine resistance is linked to multiple mutations in PfCRT, a protein that likely functions as a transporter in the parasite's digestive vacuole membrane. Rapid diagnostic assays for PfCRT mutations are already employed as surveillance tools for drug resistance. However, several reports have been published demonstrating cases with CO resistance. Sporadic cases have been reported as well as one large scale study demonstrated 12.4% resistance. However, all these reports were based on treatment failure (in vivo). rather than in vitro or molecular bases. Evidence suggests a crucial role for a point mutation in the P. falciparum chloroquine resistance transporter (pfcrt) gene on chromosome 7 in conferring CQ resistance. The mutation in the K76 codon in 3 cases out of 60 (5%) using ApoI restriction enzyme was detected. Although the percentage of drug resistance was not quite disturbing, but represented the possible establishment of chloroquine-resistant P. falciparum in Saudi Arabia, or the beginning of resistant strains by labors coming from abroad. Cross-border importation of resistant strains from neighboring countries must be considered. In vivo tests must be conducted parallel with the molecular markers to estimate more precisely the actual prevalence of resistance. Validation of molecular markers is urgently required and needs strong collaborative partnerships between subregional and regional networks.


Asunto(s)
Antimaláricos/uso terapéutico , Cloroquina/uso terapéutico , Resistencia a Medicamentos/genética , Malaria Falciparum/tratamiento farmacológico , Proteínas de Transporte de Membrana/genética , Plasmodium falciparum/efectos de los fármacos , Proteínas Protozoarias/genética , Animales , Secuencia de Bases , ADN Protozoario/análisis , Marcadores Genéticos , Humanos , Malaria Falciparum/parasitología , Técnicas de Amplificación de Ácido Nucleico , Mutación Puntual/genética , Arabia Saudita , Insuficiencia del Tratamiento
3.
J Egypt Soc Parasitol ; 39(1): 1-9, 2009 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-19530605

RESUMEN

Commercial latex agglutination (LA) was assessed for Toxoplasma antibody screening. The sensitivity and specificity were compared with the reference standard indirect immunofluorescence (IFA). A total of 186 sera were collected from May 2008-October 2008 for Toxoplasma antibody by LA & IFA. Antibody to T. gondii 51/186 (27.4%) were LA-positive and 42/186 (22.6%) were IFA-positive. The sensitivity, specificity and positive predictive value of LA were 100%, 93.7% & 82.3% respectively. The nine LA-false positive sera were examined for rheumatoid factor and antinuclear antibodies, but were negative and none exhibited nonspecific polar staining as a cause for the false positivity.


Asunto(s)
Técnica del Anticuerpo Fluorescente Indirecta/métodos , Toxoplasmosis/diagnóstico , Animales , Reacciones Falso Positivas , Femenino , Humanos , Pruebas de Fijación de Látex , Arabia Saudita/epidemiología , Sensibilidad y Especificidad , Toxoplasma/inmunología , Toxoplasmosis/epidemiología , Toxoplasmosis/inmunología
4.
J Egypt Soc Parasitol ; 39(1): 11-21, 2009 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-19530606

RESUMEN

A total of 200 females of whom 120 had manifestations of vaginal trichomoniasis and 80 asymptomatic ones were studied. In 54/120 symptomatic female (45%) and in 28/80 asymptomatic ones (35%), T. vaginalis was diagnosed by wet mount of bedside vaginal swab samples. Of 120 samples from symptomatic females, T. vaginalis was detected in 93 (77.5%) when cultured onto InPouch & 95 (79.16%) in modified thioglycolate media. Culturing 80 samples of asymptomatic females showed T. vaginalis in 35 (43.75%) onto either media. T. vaginalis genomic DNAs was amplified by PCR from 130 (65%) by using TVA5-TVA6 primer pair in 95 (79.16%) samples of 120 symptomatic females, and in 35 (43.75%) samples of 80 asymptomatic ones. Difference between groups was statistically significant. The motile trichomonads was detected by wet mount in 82/130 positive cultures giving 63.07% sensitivity & 100% positive predictive value (PPV). Flagellates were not detected by wet mount in any negative culture, giving 100% specificity & 59.32% negative predictive value (NPV). The wet mount diagnostic accuracy (DA) was 76%, without false-positive, but false negative was 48/130 (36.93%). DNA was amplified from 129/130 positive culture by TVA5-TVA6 primer pair, giving 99.23% sensitivity. No amplification was detected from one positive culture. DNA was not amplified from 69/70 negative culture using TVA5-TVA6 primer pair, giving 98.57% specificity, 99.23% PPV, 98.57% NPV and 99% DA.


Asunto(s)
Reacción en Cadena de la Polimerasa/métodos , Vaginitis por Trichomonas/diagnóstico , Animales , Femenino , Humanos , Sensibilidad y Especificidad , Trichomonas vaginalis/aislamiento & purificación , Vagina/parasitología
5.
J Egypt Soc Parasitol ; 39(1): 111-9, 2009 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-19530614

RESUMEN

In this work, the therapeutic effect of E-64, a broad spectrum cystine protease inhibitor against Giardia lamblia excystation was studied in vitro and in vivo. Purification of cysts from heavily infected human faecal samples followed by excystation and axenic cultivation of the emerging trophozoites in TYI-S-33 medium were done. In vivo, the response was evaluated experimentally through counting oocysts out-put every other day until the infection eradicated from the stools of infected E-64 treated mice compared to untreated. Also, the histopathological examination of the small intestine was compared between both of the infected groups. In the present study G. lamblia cysts incubated with E 64 in vitro completely failed in excystation in 90% while trophozoites released on 10% (partially excysted on 5% and completely excysted on 5%) compared to 90 % completely excysted on other non incubated (without E-64) of cysts beside, the trophozoites didn't release on 10% (partially excysted on 5% & completely non-excysted on 5%). In vivo, the evaluation of the therapeutic response proved that the decreasing in the oocysts out-put counting every other day until the infection eradicated from the stools of infected treated mice was very marked in comparison to untreated mice. The differences were statistically significant. The histopathological examination of the small intestine of infected non treated group proved that all the different pathological grades were found while in infected E-64 treated group, only grade I was detected. So, E-64 showed a good therapeutic effect which raises its use in the treatment of human giardiasis


Asunto(s)
Inhibidores de Cisteína Proteinasa/farmacología , Giardia lamblia/efectos de los fármacos , Giardiasis/tratamiento farmacológico , Leucina/análogos & derivados , Animales , Leucina/farmacología , Ratones
6.
J Egypt Soc Parasitol ; 38(2): 329-38, 2008 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-18853608

RESUMEN

This study compared conventional PCR with microscopy and 2 rapid detection methods, the pLDH which detected lactic dehydrogenase enzyme produced by actively metabolizing organisms and the malaria antibody tests. The sensitivity of PCR was 1 parasite/microl, i.e.: 50 times more sensitive than microscopy. When PCR was compared with microscopy, the sensitivity and specificity were 90% & 100% respectively. The sensitivity recorded was pLDH test in comparison to PCR (95%). The malaria antibody test recorded the least sensitivity (68%) PCR proved as the gold standard for evaluation of applied tests and the newly introduced ones. In absence of an expert microscopist, the pLDH test could substitute for microscopy. The test proved valuable to assess clinical cure, and predict drug resistance. Its advantage over microscopy was the ability to diagnose infection with low parasitemic patients. Antibody rapid tests might be not valuable in acute cases, but still accepted as a tool in epidemiological studies and in screening patients in blood banks in malaria endemic areas.


Asunto(s)
Anticuerpos Antiprotozoarios/sangre , ADN Protozoario/aislamiento & purificación , Malaria/diagnóstico , Microscopía/métodos , Plasmodium , Reacción en Cadena de la Polimerasa/métodos , Animales , Humanos , L-Lactato Deshidrogenasa/análisis , L-Lactato Deshidrogenasa/inmunología , Tamizaje Masivo , Plasmodium/inmunología , Plasmodium/aislamiento & purificación , Sensibilidad y Especificidad
7.
J Egypt Soc Parasitol ; 38(2): 339-50, 2008 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-18853609

RESUMEN

A real-time PCR assay with conventional microscopy by Giemsa-stained blood films was used. PCR was completed in an hour and identified the Plasmodium species in a single reaction. Blood was collected, and DNA was extracted. A genus-specific primer set corresponding to 18S ribosomal RNA was used to amplify target sequence. Fluorescence resonance energy technology hybridization probes were designed for P. falciparum over a region containing base pair mismatches allowed Plasmodium species differentiation. Microscopically positive patients (n = 60) were positive with real-time assay (100% sensitivity). 58 were single-species infections caused by P. falciparum; mixed infections (P. falciparum & P. vivax) were shown by real-time assay. Six out of 30 negative microscopy specimens were positive by real-time PCR (80% specificity). The discrepant results could be due to the subjective nature of microscopy and analytical objectivity of PCR, and high analytical sensitivity of real-time assay (1 parasite/microl) compared to microscopy (50 parasites/microl). Six patients were retested with ICT malaria test and 4 were positive showing that PCR results were correct. There was low correlation between parasitemia by microscopy and gene copy number for P. falciparum (r = 0.2; P = 0.05 [Spearman]).


Asunto(s)
ADN Protozoario/análisis , Malaria/diagnóstico , Plasmodium/aislamiento & purificación , Reacción en Cadena de la Polimerasa/métodos , Animales , Recolección de Muestras de Sangre , ADN Protozoario/química , ADN Protozoario/genética , Amplificación de Genes , Humanos , Malaria/parasitología , Microscopía , Parasitemia/diagnóstico , ARN Ribosómico 18S/química , ARN Ribosómico 18S/genética , Arabia Saudita , Sensibilidad y Especificidad , Especificidad de la Especie
8.
J Egypt Soc Parasitol ; 38(2): 359-70, 2008 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-18853611

RESUMEN

To gain insight into potential relationships between tumor necrosis factor alpha (TNF-alpha), interleukin 10 (IL-10), erythropoietin (EPO), and anemia in acute malaria, 90 children 3 to 11 years with acute malaria were studied. According to parasitemia and hemoglobin levels, they were divided into 3 groups: G1 (mild): asexual low-density Plasmodium falciparum parasitemia <8000 parasites/ul and hemoglobin levels >8g/dl. G2 (high-density uncomplicated): asexual high-density parasitemia (>8000 parasites/ul, with hemoglobin levels >8 g/dl. G3 (anemia): with severe malaria symptoms and parasitemia with anemia (hemoglobin levels <8 g/dl). Hospital controls included 10 children with matching age group who required inpatient management but had no malaria parasitemia. Good marrow response was in G1 & G2 showed by elevation of serum EPO and soluble transferring receptors (sTfR) and increased red cell distribution width (RDW). In G3, bone marrow suppression was in spite of increased EPO level in response to anemia. TNF-alpha level was significantly higher G2 and G3 (P.05). IL-10 levels in G1 were significantly higher than in hospital control group (P<0.05). The highest level of IL-10 was in G2. The mean IL-10 to TNF-alpha ratio in G2 (4.64) was significantly higher (P<.005) than in G3 (mean ratio, 1.77).


Asunto(s)
Anemia/sangre , Eritropoyetina/sangre , Interleucina-10/sangre , Malaria Falciparum/sangre , Factor de Necrosis Tumoral alfa/sangre , Anemia/epidemiología , Animales , Estudios de Casos y Controles , Niño , Preescolar , Femenino , Hemoglobinas , Humanos , Masculino , Parasitemia/sangre , Plasmodium falciparum , Arabia Saudita
9.
J Egypt Soc Parasitol ; 38(2): 453-64, 2008 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-18853619

RESUMEN

A total of 180 children of age group 5-12 years old in both sexes, of whom 90 were symptomatic and negative for other parasites, rotavirus or pathogenic bacteria. Another 90 children were asymptomatic, but with B. hominis in stools. Direct smear, formaline-ethyl acetate sedimentation concentration, kinyon carbol-fuchin stain, stool culture, enzyme immunoassay, culturing, morphometric study, gel electrophoresis and experimental infection of mice were done. The results showed that the central body cysts (CB), granular and multivacuolar forms isolated from symptomatic patients were larger than those from asymptomatic ones. The CB form was common compared to other forms and isolated from 104 cases. B. hominis infection was prevalent among males rather than females (60.5% versus 39.5%). The clinical data showed that diarrhea was the most common symptom (58.9%). The infection intensity had a direct relation with illness duration. The polyacrylamide gel electrophoresis showed that isolates from symptomatic and asymptomatic patients ranged between 24-130 kDa. All isolates showed similar banding patterns. Only minor differences was in low MW (30, 50 kDa) and in high MW (118 kDa) in samples from symptomatic patients. The histopathological examination of caecum, colon and small intestine of B. hominis mice infected from symptommatic patients showed infiltration with inflammatory cells and tissue invasion by the parasite.


Asunto(s)
Infecciones por Blastocystis/epidemiología , Blastocystis hominis/aislamiento & purificación , Heces/parasitología , Gastroenteritis/epidemiología , Gastroenteritis/parasitología , Animales , Bioensayo , Infecciones por Blastocystis/patología , Niño , Preescolar , Femenino , Gastroenteritis/patología , Humanos , Masculino , Ratones , Peso Molecular , Prevalencia , Índice de Severidad de la Enfermedad , Factores Sexuales
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...