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1.
Biomed Res Int ; 2021: 5545331, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34235218

RESUMO

World Health Organization (WHO) has approved only one treatment for schistosomiasis, praziquantel (PZQ), but some poor efficacy was noticed in patients during the early stage of infection. Therefore, researchers have intensified their efforts to research new alternative medicines to treat schistosomiasis. In the present study, in vitro as well as in vivo studies have been accomplished to evaluate the effect of Origanum majorana, Ziziphus spina-christi, and Salvia fruticosa extracts in a different concentration 500, 250, 125, 62.5, and 31.25 µg/ml on golden hamster infected by Egyptian strains of schistosome (Schistosoma haematobium). In vitro, the adult worms and schistosomula of S. haematobium were investigated in RPMI-1640 medium for 48 hrs. The results showed that the concentration 500, 250, and 125 µg/ml of Origanum majorana, and Ziziphus spina-christi caused dead of 100% of Egyptian Schistosoma strains of adult worm and schistosomula of S. haematobium within 6 to 12 hrs of incubation. On the other hand, the extract of Salvia fruticosa at concentrations 500, 250, and 125 µg/ml showed death 100% parasites after 12 to 24 hrs of incubation. Inclusion, Origanum majorana, and Ziziphus spina-christi showed effectiveness against Egyptian Schistosoma strains (S. haematobium), a slight decrease in Salvia fruticosa was observed. Therefore, these medical plant extracts may be used as a safe and effective treatment for schistosomiasis.


Assuntos
Antiprotozoários/farmacologia , Origanum , Extratos Vegetais/farmacologia , Praziquantel/farmacologia , Salvia , Schistosoma haematobium/efeitos dos fármacos , Esquistossomose Urinária/tratamento farmacológico , Ziziphus , Animais , Chlorocebus aethiops , Técnicas In Vitro , Masculino , Mesocricetus , Microscopia Eletrônica de Varredura , Resultado do Tratamento , Células Vero
2.
Lancet Glob Health ; 7(8): e1118-e1129, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31255591

RESUMO

BACKGROUND: Elimination of schistosomiasis as a public health problem and interruption of transmission in selected areas are targets set by WHO for 2025. Our aim was to assess biannual mass drug administration (MDA) applied alone or with complementary snail control or behaviour change interventions for the reduction of Schistosoma haematobium prevalence and infection intensity in children from Zanzibar and to compare the effect between the clusters. METHODS: In a 5-year repeated cross-sectional cluster-randomised trial, 90 shehias (small administrative regions; clusters) in Zanzibar eligible owing to available natural open freshwater bodies and public primary schools were randomly allocated (ratio 1:1:1) to receive one of three interventions: biannual MDA with praziquantel alone (arm 1) or in combination with snail control (arm 2), or behaviour change activities (arm 3). Neither participants nor field or laboratory personnel were blinded to the intervention arms. From 2012 to 2017, annually, a single urine sample was collected from approximately 100 children aged 9-12 years in the main public primary school of each shehia. The primary outcome was S haematobium infection prevalence and intensity in 9-12-year-old children after 5 years of follow-up. This study is completed and was registered with the ISRCTN, number 48837681. FINDINGS: The trial was done from Nov 1, 2011, through to Dec 31, 2017 and recruitment took place from Nov 2, 2011, until May 17, 2017. At baseline we enrolled 8278 participants, of whom 2899 (35%) were randomly allocated to arm 1, 2741 (33%) to arm 2, and 2638 (32%) to arm 3. 120 (4·2%) of 2853 in arm 1, 209 (7·8%) of 2688 in arm 2, and 167 (6·4%) of 2613 in arm 3 had S haematobium infections at baseline. Heavy infections (≥50 eggs per 10 mL of urine) were found in 126 (1·6%) of 8073 children at baseline. At the 5-year endline survey, 46 (1·4%) of 3184 in arm 1, 56 (1·7%) of 3217 (odds ratio [OR] 1·2 [95% CI 0·6-2·7] vs arm 1) in arm 2, and 58 (1·9%) of 3080 (1·3 [0·6-2·9]) in arm 3 had S haematobium infections. Heavy infections were detected in 33 (0·3%) of 9462 children. INTERPRETATION: Biannual MDA substantially reduced the S haematobium prevalence and infection intensity but was insufficient to interrupt transmission. Although snail control or behaviour change activities did not significantly boost the effect of MDA in our study, they might enhance interruption of transmission when tailored to focal endemicity and applied for a longer period. It is now necessary to focus on reducing prevalence in remaining hotspot areas and to introduce new methods of surveillance and public health response so that the important gains can be maintained and advanced. FUNDING: University of Georgia Research Foundation Inc and Bill & Melinda Gates Foundation.


Assuntos
Anti-Helmínticos/administração & dosagem , Prestação Integrada de Cuidados de Saúde , Erradicação de Doenças , Praziquantel/administração & dosagem , Schistosoma haematobium/efeitos dos fármacos , Esquistossomose Urinária/tratamento farmacológico , Esquistossomose Urinária/prevenção & controle , Animais , Criança , Análise por Conglomerados , Feminino , Promoção da Saúde , Humanos , Masculino , Schistosoma haematobium/crescimento & desenvolvimento , Esquistossomose Urinária/epidemiologia , Tanzânia/epidemiologia
3.
Bull World Health Organ ; 94(1): 37-45, 2016 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-26769995

RESUMO

OBJECTIVE: To assess the impact of a decade of biennial mass administration of praziquantel on schistosomiasis in school-age children in Burkina Faso. METHODS: In 2013, in a national assessment based on 22 sentinel sites, 3514 school children aged 7-11 years were checked for Schistosoma haematobium and Schistosoma mansoni infection by the examination of urine and stool samples, respectively. We analysed the observed prevalence and intensity of infections and compared these with the relevant results of earlier surveys in Burkina Faso. FINDINGS: S. haematobium was detected in 287/3514 school children (adjusted prevalence: 8.76%, range across sentinel sites: 0.0-56.3%; median: 2.5%). The prevalence of S. haematobium infection was higher in the children from the Centre-Est, Est and Sahel regions than in those from Burkina Faso's other eight regions with sentinel sites (P < 0.001). The adjusted arithmetic mean intensity of S. haematobium infection, among all children, was 6.0 eggs per 10 ml urine. Less than 1% of the children in six regions had heavy S. haematobium infections - i.e. at least 50 eggs per 10 ml urine - but such infections were detected in 8.75% (28/320) and 11.56% (37/320) of the children from the Centre-Est and Sahel regions, respectively. Schistosoma mansoni was only detected in two regions and 43 children - i.e. 1 (0.31%) of the 320 from Centre-Sud and 42 (8.75%) of the 480 from Hauts Bassins. CONCLUSION: By mass use of preventive chemotherapy, Burkina Faso may have eliminated schistosomiasis as a public health problem in eight regions and controlled schistosome-related morbidity in another three regions.


Assuntos
Praziquantel/administração & dosagem , Schistosoma haematobium/isolamento & purificação , Esquistossomose Urinária/prevenção & controle , Animais , Anti-Helmínticos/administração & dosagem , Anti-Helmínticos/economia , Anti-Helmínticos/uso terapêutico , Burkina Faso/epidemiologia , Quimioprevenção/economia , Quimioprevenção/métodos , Quimioprevenção/estatística & dados numéricos , Criança , Análise Custo-Benefício , Doenças Endêmicas/prevenção & controle , Fezes/parasitologia , Feminino , Humanos , Masculino , Programas Nacionais de Saúde/organização & administração , Programas Nacionais de Saúde/estatística & dados numéricos , Praziquantel/economia , Praziquantel/uso terapêutico , Prevalência , Avaliação de Programas e Projetos de Saúde , Schistosoma haematobium/efeitos dos fármacos , Esquistossomose Urinária/economia , Esquistossomose Urinária/epidemiologia , Serviços de Saúde Escolar/organização & administração , Serviços de Saúde Escolar/estatística & dados numéricos , Urina/parasitologia
4.
Orv Hetil ; 156(50): 2045-51, 2015 Dec 13.
Artigo em Húngaro | MEDLINE | ID: mdl-26639646

RESUMO

Significant percentage of today's knowledge of ancient Egyptian medicine has been acquired from papyri left behind from various periods of Egyptian history. The longest and the most comprehensive is the Ebers papyrus, kept at the University Museum of Leipzig, which was written more than one thousand years before Hippocrates (c. 460-377 BC). One of the riddles among the prescriptions of the Ebers papyrus Eb20 has been used in order to remove the so called "wemyt" weremit from the abdomen with the help of a drink, which consists of "jnnk", Conyza dioscoridis in milk or sweet beer. The authors assume that the disease could be an infection of Schistosoma haematobium and/or Schistosoma mansoni. Nowadays the tea of Conyza dioscoridis is widely used as an important part of traditional medicine against rheumatism, intestinal distention and cramps, as well as an antiperspirant, and with external use for wound healing. The authors' intent is to interpret the efficacy of the above-mentioned ancient prescription with the help of modern medical and pharmaceutical knowledge.


Assuntos
Conyza , Medicina Tradicional/história , Schistosoma/efeitos dos fármacos , Esquistossomose/tratamento farmacológico , Esquistossomose/história , Animais , Prescrições de Medicamentos/história , Antigo Egito , História Antiga , Humanos , Medicina Tradicional/métodos , Schistosoma haematobium/efeitos dos fármacos , Schistosoma mansoni/efeitos dos fármacos , Esquistossomose Urinária/história , Esquistossomose mansoni/história
5.
Parasit Vectors ; 5: 165, 2012 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-22876861

RESUMO

BACKGROUND: The development of novel antischistosomal drugs is crucial, as currently no vaccine and only a single drug is available for the treatment of schistosomiasis. Fast and accurate in vitro assays are urgently needed to identify new drug candidates and research efforts should include Schistosoma haematobium. The aim of the present study was to develop a S. haematobium drug sensitivity assay based on newly transformed schistosomula (NTS). METHODS: We first undertook comparative studies on the cercarial emergence rhythms of the intermediate host snails Biomphalaria glabrata (S. mansoni) and Bulinus truncatus (S. haematobium). Two transformation methods as well as three purification methods were studied on S. haematobium cercariae in order to produce a large number of viable and clean NTS. Known antischistosomal drugs were tested in the established NTS assay in vitro. Drug effects were evaluated either microscopically or fluorometrically, using a resazurin based viability marker. Microscopically obtained IC50 values were compared with results obtained for S. mansoni. RESULTS: A circadian rhythm existed in both snail species. Infected B. truncatus snails shed less cercariae than B. glabrata during the testing period. The highest transformation rate (69%) of S. haematobium cercariae into NTS was obtained with the vortex transformation (mechanical input) and the highest purification factor was observed using Percoll®. The fluorimetric readout based on resazurin was very precise in detecting dead or/and severely damaged schistosomula. CONCLUSIONS: With the use of viability markers such as resazurin, drug screening assays using S. haematobium NTS can be efficiently performed. However, drugs acting on the morphology and motility of S. haematobium NTS, such as metrifonate are missed. Drug sensitivity assays with NTS of both species, S. haematobium and S. mansoni, showed very similar results using known antischistosomal drugs. The S. mansoni NTS assay might be more suitable as primary screen in drug discovery efforts, which ultimately aim for a broad-spectrum antischistosomal drug as a larger number of S. mansoni NTS can be generated.


Assuntos
Anti-Helmínticos/farmacologia , Avaliação Pré-Clínica de Medicamentos/métodos , Schistosoma haematobium/efeitos dos fármacos , Animais , Glucose/farmacologia , Caramujos/parasitologia
6.
Int J Antimicrob Agents ; 39(3): 232-9, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22240411

RESUMO

We have recently shown that in vitro and in vivo exposure of Schistosoma mansoni and Schistosoma haematobium to 5-10mM arachidonic acid (ARA) induces parasite surface membrane disintegration and eventual attrition. Here we report on the optimum ARA dose and post-infection treatment time for maximum schistosome demise in hamsters. A series of four experiments for each schistosome species indicated that oral administration of ARA after patency led to a highly significant (P<0.02 to <0.001) reduction in worm burden accompanied by a significant (P<0.05) decrease in worm egg load. ARA-mediated attrition in vivo appeared to be associated with high titres of serum antibodies to tegumental antigens. In support, serum antibodies from patently infected and ARA-treated hamsters readily bound to the surface membrane of ARA-exposed adult worms, as judged by indirect membrane immunofluorescence. More importantly, addition of serum antibodies and peripheral blood mononuclear cells significantly enhanced ARA-mediated adult worm attrition in vitro. These data together show that the schistosomicidal effect of ARA in laboratory animals is enhanced by immune effectors and is highly efficacious and entirely safe.


Assuntos
Ácido Araquidônico/farmacologia , Schistosoma haematobium/patogenicidade , Schistosoma mansoni/patogenicidade , Esquistossomose/tratamento farmacológico , Esquistossomicidas/farmacologia , Animais , Antígenos de Helmintos/metabolismo , Ácido Araquidônico/administração & dosagem , Membrana Celular/efeitos dos fármacos , Membrana Celular/metabolismo , Cricetinae , Avaliação Pré-Clínica de Medicamentos , Feminino , Técnica Indireta de Fluorescência para Anticorpo , Leucócitos Mononucleares/metabolismo , Fígado/parasitologia , Fígado/patologia , Masculino , Mesocricetus , Microscopia Eletrônica de Varredura , Contagem de Ovos de Parasitas , Schistosoma haematobium/efeitos dos fármacos , Schistosoma mansoni/efeitos dos fármacos , Esquistossomose/parasitologia , Esquistossomicidas/administração & dosagem , Fatores de Tempo
7.
Food Nutr Bull ; 33(4): 235-41, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23424889

RESUMO

BACKGROUND: Relationships among Schistosoma haematobium, anemia, and iron deficiency have been documented, and all have been found to be associated with a decline in school attendance and lower performance. OBJECTIVE: To assess the effect of single or combined iron and multiple micronutrients and/or praziquantel on school attendance and achievement in randomly selected 7- to 12-year-old anemic children with documented S. haematobium infection (n = 406) in Mali over a 3-month period. METHODS: Schistosomiasis infection was diagnosed by the presence of schistosome eggs in the urine. Venous blood samples (5 mL) were drawn from an antecubital vein for hemoglobin assessment. Children were randomly assigned to one of four treatment groups: praziquantel alone, praziquantel + iron, praziquantel + multiple micronutrients, and praziquantel + multiple micronutrients + iron. School attendance was defined by the number of days the child was absent from class. Achievement was defined by the child's overall school grades. RESULTS: Changes within treatment groups from baseline to the end of study were found for attendance (p < .001) but not for achievement (p > .05). Significant supplement treatments by age group interactions were found in 7- to 9-year-old children for attendance. Further exploration of treatment effects in this age group showed that only iron treatment's main effect was significant on attendance (p = .049) and was of borderline significance on school grades (p = .08). CONCLUSIONS: Combined praziquantel and iron treatment improved children's school attendance and performance better than praziquantel alone, particularly among younger children.


Assuntos
Anemia/tratamento farmacológico , Suplementos Nutricionais , Ferro da Dieta/uso terapêutico , Micronutrientes/uso terapêutico , Esquistossomose Urinária/tratamento farmacológico , Absenteísmo , Animais , Criança , Feminino , Hemoglobinas/análise , Hemoglobinas/efeitos dos fármacos , Humanos , Modelos Lineares , Masculino , Mali/epidemiologia , Análise Multivariada , Contagem de Ovos de Parasitas , Praziquantel/uso terapêutico , Prevalência , Estudos Prospectivos , Schistosoma haematobium/efeitos dos fármacos , Esquistossomose Urinária/sangue , Esquistossomose Urinária/epidemiologia , Instituições Acadêmicas
8.
Pharm Biol ; 48(7): 775-9, 2010 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-20645776

RESUMO

Conflicting reports are found in the literature about the efficacy of Mirazid (MZ), which is a special formulation of myrrh obtained from the stem of Commiphora molmol (Nees), Engl. tree (Burseraceae), as an antischistosomal drug. This initiated the present study to further assess this drug in experimental schistosomiasis hematobium. The drug was administered orally to hamsters infected with Schistosoma hematobium ( Bilharz, 1852 ) using 500 mg/kg body weight for six successive days on an empty stomach. The drug effect was examined after three periods: 4, 8 and 12 weeks post-treatment. Emphasis was given to certain parameters such as change in worm load, number of ova/mg tissue, oogram pattern and number of ova/g stool, and tegumental changes in the worms by electron microscopy after prolonged observation periods. The results showed very slight 3.4% worm reduction by MZ after the longest evaluation period (12 weeks), versus very high reduction (100%) by the reference drug praziquantel (PZQ). In comparison with the untreated control no change was found in the number of ova/mg tissue in MZ-treated hamsters regardless of the date of observation (4-12 weeks), versus significantly high reduction (99.6%) observed in the case of PZQ treatment. However, a significant decrease (22%) in the ratio of immature and increase in dead ova in tissues of MZ-treated hamsters was obvious at 12 weeks post treatment. In MZ-treated animals, a slight reduction (18.3%) in the number of stool eggs versus absence of eggs in PZQ-treated animals 12 weeks after treatment. Scanning electron microscopic examination of S. hematobium worms revealed intact tubercles, spines and sensory bulbs and no effect of the ventral side after MZ treatment. Meanwhile, PZQ treatment revealed extensive disruption of the tegument worm. Therefore, this experimental study gives extra support to previously reported negative evaluation about the effectiveness of this drug in the treatment of schistosomiasis against many other published positive results. This controversy about the efficacy of MZ may be attributed to inconsistency of its material which is obtained from natural origin.


Assuntos
Extratos Vegetais/uso terapêutico , Schistosoma haematobium/efeitos dos fármacos , Esquistossomose Urinária/tratamento farmacológico , Esquistossomicidas/uso terapêutico , Animais , Bulinus/parasitologia , Commiphora , Cricetinae , Avaliação Pré-Clínica de Medicamentos , Mesocricetus , Praziquantel/uso terapêutico , Resinas Vegetais , Esquistossomose Urinária/parasitologia
9.
J Parasitol ; 91(5): 1094-102, 2005 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-16419753

RESUMO

Incubation of Schistosoma mansoni lung-stage larvae in 90% corn oil for 6 hr was shown to elicit exposure of their, otherwise masked, apical membrane antigens to binding of anti-schistosome antibodies in the indirect membrane immunofluorescence test (IF). The possibility that unsaturated fatty acids (FA) are responsible for this effect was herein supported by IF data on ex vivo lung-stage larvae of S. mansoni and S. haematobium incubated for 1/2-2 hr with 80% corn oil, 50% olive oil, or 10-20 microM arachidonic acid. Treatment with unsaturated FA followed by filipin staining for cholesterol visualization indicated that unsaturated FA do not induce exposure of schistosomular surface membrane antigens via extraction of surface membrane cholesterol. Evidence using inhibitors and stimulators of neutral sphingomyelinase suggested that unsaturated FA perhaps activate worm tegument-bound neutral sphingomyelinase, leading to sphingomyelin hydrolysis and changes in surface membrane fluidity. Larval apical membrane antigens are, thus, allowed to diffuse freely in the plane of the membrane and bind specific antibodies in IE Excessive sphingomyelin hydrolysis might explain why high FA concentrations or long incubation periods eventually lead to larval death. The significant decrease (P < 0.01) in S. mansoni and increase (P < 0.02) in S. haematobium worm recovery in BALB/c mice given unsaturated FA-high and -poor diets, respectively, indicated these findings have in vivo relevance and led to the proposal that unsaturated FA likely plays a role in natural attrition of S. mansoni and S. haematobium lung-stage larvae.


Assuntos
Gorduras Insaturadas na Dieta/administração & dosagem , Ácidos Graxos Insaturados/farmacologia , Pulmão/parasitologia , Schistosoma haematobium/efeitos dos fármacos , Schistosoma mansoni/efeitos dos fármacos , Animais , Antígenos de Helmintos/imunologia , Antígenos de Superfície/imunologia , Colesterol/análise , Cricetinae , Gorduras Insaturadas na Dieta/farmacologia , Ativação Enzimática/efeitos dos fármacos , Ácidos Graxos Insaturados/administração & dosagem , Filipina , Técnica Indireta de Fluorescência para Anticorpo , Larva/efeitos dos fármacos , Larva/enzimologia , Larva/imunologia , Masculino , Mesocricetus , Camundongos , Camundongos Endogâmicos BALB C , Distribuição Aleatória , Schistosoma haematobium/enzimologia , Schistosoma haematobium/imunologia , Schistosoma mansoni/enzimologia , Schistosoma mansoni/imunologia , Esquistossomose Urinária/dietoterapia , Esquistossomose Urinária/parasitologia , Esquistossomose mansoni/dietoterapia , Esquistossomose mansoni/parasitologia , Esfingomielina Fosfodiesterase/antagonistas & inibidores , Esfingomielina Fosfodiesterase/efeitos dos fármacos , Esfingomielina Fosfodiesterase/metabolismo , Esfingomielinas/metabolismo , Coloração e Rotulagem/métodos
10.
J Egypt Soc Parasitol ; 33(3): 761-76, 2003 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-14708852

RESUMO

No doubt, schistosomiasis tops all the endemic parasitic diseases world-wide particularly in Egypt. This study evaluated the efficacy of Mirazid (Commiphora molmol) in the treatment of parasitologically and clinically and ultrasonography confirmed cases of schistosomiasis haematobium in Tatoon village. A sum of 70 out of 885 individuals of both sexes (>15 to 60 years old) screened for S. haematobium infection were selected. They had light infection (1-10 eggs/10 ml.), moderate infection (10-100 eggs/10 ml.) and heavy infection (>100/10 ml.). They were subjected to urine and stool analysis, renal function tests, clinical examination and abdomino-pelvic ultrasound. They were treated with Mirazid as 10 mgm/Kg. However, eight of them were unable to swallow the drug. Out of the 62 schistosomiasis haematobium patients, 57 (91.9%) were cured after two months follow up and the cure rate reached 59 (95.2%) on the 3rd month post-Mirazid treatment. The cure result was evaluated clinically, parasitologically and ultrasonographically. So, Mirazid in a dose of two capsules (600 mgm) on an empty stomach before breakfast for six successive days proved to be very effective and safe in the treatment of schistosomiasis haematobium.


Assuntos
Commiphora/química , Fitoterapia , Extratos Vegetais/uso terapêutico , Esquistossomose Urinária/tratamento farmacológico , Esquistossomicidas/uso terapêutico , Adolescente , Adulto , Animais , Relação Dose-Resposta a Droga , Egito , Fezes/parasitologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Extratos Vegetais/farmacologia , Schistosoma haematobium/efeitos dos fármacos , Esquistossomose Urinária/diagnóstico por imagem , Esquistossomose Urinária/prevenção & controle , Esquistossomicidas/farmacologia , Resultado do Tratamento , Ultrassonografia , Urina/parasitologia
11.
Ann Trop Med Parasitol ; 96(6): 587-93, 2002 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-12396321

RESUMO

At 1 mg/litre, an ethyl-acetate extract of the molluscicidal plant Origanum compactum Benth. (Lamiaceae) immobilized all of the furcocercariae of Schistosoma haematobium exposed to it, within 15 min. This apparently cercaricidal activity was attributed to the presence of terpenoids and flavonoids in the extract. Encouragingly, several non-target aquatic organisms (larvae of Culex pipiens and Artemia salina and adult Gambusia affinis) and Drosophila melanogaster appeared largely unaffected by exposure to concentrations of the extract that kill S. haematobium cercariae and Bulinus truncatus.


Assuntos
Origanum , Fitoterapia/métodos , Schistosoma haematobium/efeitos dos fármacos , Esquistossomicidas/farmacologia , Animais , Artemia/efeitos dos fármacos , Culex/efeitos dos fármacos , Drosophila melanogaster/efeitos dos fármacos , Avaliação Pré-Clínica de Medicamentos , Óleos Voláteis/química , Origanum/química , Testes de Sensibilidade Parasitária/métodos , Extratos Vegetais/química , Extratos Vegetais/farmacologia
12.
Parasitol Int ; 50(3): 175-83, 2001 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-11595574

RESUMO

We report the findings of a detailed temporal study on tegumental alterations in juvenile Schistosoma haematobium, induced by artemether, using scanning electron microscopy. Hamsters infected with S. haematobium cercariae for 28 days were treated intragastrically with a single dose of 300 mg/kg artemether. Groups of two hamsters were killed 24 h, 72 h and 7 days after treatment, and schistosomula were recovered from livers by perfusion and subsequent systematic examination of the tissue, before routinely processing for scanning electron microscopic examination. Most schistosomula collected 24 h after artemether administration showed severe tegumental damage, usually including swelling, fusion, vesiculation, peeling and collapse of enlarged sensory structures. After 72 h, tegumental damage had increased and schistosomula generally showed contraction with extensive swelling, erosion and peeling of the tegument. Seven days post-treatment, severe tegumental damage was only seen in a single male specimen with swelling of the worm body and destruction of the oral sucker. The other schistosomula showed only light to moderate damage, suggesting that schistosomula surviving the treatment began to recover. Our findings of tegumental damage following artemether treatment correlate with the efficacy of this novel antischistosomal drug in killing the juvenile stages of S. haematobium and complement recent findings with S. japonicum and S. mansoni.


Assuntos
Artemisininas , Schistosoma haematobium/efeitos dos fármacos , Schistosoma haematobium/ultraestrutura , Esquistossomose Urinária/tratamento farmacológico , Esquistossomicidas/farmacologia , Sesquiterpenos/farmacologia , Animais , Artemeter , Cricetinae , Feminino , Masculino , Microscopia Eletrônica de Varredura , Esquistossomose Urinária/parasitologia , Sesquiterpenos/uso terapêutico
14.
Acta Trop ; 79(2): 135-41, 2001 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-11369306

RESUMO

Histopathological changes in juvenile Schistosoma haematobium, caused by artemether administered to the infected hamsters, were studied. Hamsters were infected with S. haematobium cercariae, and after 28 days, a single dose of artemether (300 mg/kg) was administered intragastrically. After 24 h, 72 h and 7 days, groups of two hamsters were sacrificed, and livers were removed, fixed and processed routinely, and examined by light microscopy. After 24 h, 93% of the schistosomulae examined showed degeneration, which included swelling of the tegument, adherence of inflammatory cells to the damaged tegument, collapsed and damaged intestine, and infiltration of inflammatory cells, predominantly lymphocytes. After 72 h, the intensity of damage increased, including severe swelling of the tegument, loss of definition in the internal structures, collapse of intestine accompanied by release of pigment particles to the parenchymal tissues, and emergence of dead schistosomulae. Seven days after treatment, the number of dead schistosomulae increased, and most of them developed to an early- or late stage of dead worm granuloma. Meanwhile, 12% of the schistosomulae showed a normal appearance, which suggested that those schistosomulae that had survived the treatment were recovered to normal. The results demonstrated that artemether effectively acts against the juvenile stages of S. haematobium and confirms earlier results with S. japonicum and S. mansoni.


Assuntos
Artemisininas , Fígado/efeitos dos fármacos , Schistosoma haematobium/efeitos dos fármacos , Esquistossomose Urinária/tratamento farmacológico , Esquistossomicidas/uso terapêutico , Sesquiterpenos/uso terapêutico , Animais , Artemeter , Cricetinae , Fígado/patologia , Masculino
15.
J Ethnopharmacol ; 75(1): 45-50, 2001 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-11282442

RESUMO

Leaf extracts of 20 Combretum species, many of which are used in southern African traditional medicine, were screened for anti-inflammatory, anthelmintic, anti-bilharzia (antischistosomal) and DNA-damaging activity. Significant activity in more than one bioassay was exhibited by Combretum apiculatum, Combretum hereroense, Combretum molle and Combretum mossambicense. Ethyl acetate extracts were generally most active, followed by acetone and then water extracts.


Assuntos
Extratos Vegetais/farmacologia , Rosales/química , Animais , Anti-Helmínticos/farmacologia , Anti-Inflamatórios não Esteroides/farmacologia , Dano ao DNA , Schistosoma haematobium/efeitos dos fármacos , Especificidade da Espécie
16.
Trans R Soc Trop Med Hyg ; 95(1): 67-71, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11280070

RESUMO

We conducted experiments in vitro to assess the effect of artemether in combination with haemin on adult Schistosoma japonicum, S. mansoni and S. haematobium. When schistosomes were maintained in a medium containing artemether at concentrations of 20 micrograms/mL or less for 72 h, no apparent effect on the schistosomes was seen. When the medium contained 50 or 100 micrograms/mL haemin as well as artemether, the schistosomes showed decreased motor activity 2-24 h after exposure, which was followed by the staining of the whole worm body a reddish-yellow colour, dilatation of the intestine, and extensive vesiculation of the tegument. Some of the schistosomes died 24 h after exposure, and almost all died within 48-72 h. When schistosomes were exposed to the same concentrations of haemin alone, they were stained a light yellow colour but there was no apparent effect on their survival. Our findings suggest that artemether interacts with haemin to exert a toxic effect on the worms, which might be of importance in the further elucidation of the mechanism of action of artemether on schistosomes.


Assuntos
Antiprotozoários/uso terapêutico , Artemisininas , Hemina/uso terapêutico , Esquistossomose Urinária/tratamento farmacológico , Esquistossomose Japônica/tratamento farmacológico , Esquistossomose mansoni/tratamento farmacológico , Sesquiterpenos/uso terapêutico , Animais , Artemeter , Combinação de Medicamentos , Feminino , Masculino , Camundongos , Testes de Sensibilidade Parasitária , Polietilenoglicóis/uso terapêutico , Schistosoma haematobium/efeitos dos fármacos , Schistosoma japonicum/efeitos dos fármacos , Schistosoma mansoni/efeitos dos fármacos
17.
J Ethnopharmacol ; 73(1-2): 209-14, 2000 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-11025158

RESUMO

Urinary schistosomiasis is treated traditionally by means of herbal remedies. Forty-eight South African plant species were identified as possible antischistosomic plants. Twenty-one of these plant species were collected in order to investigate their antischistosomal properties. Crude extracts of the plant materials were screened against the schistosomula of the species Schistosoma haematobium. Cercariae were obtained from Bulinus africanus snails through an in vitro technique. By subjecting the cercariae to a sheering stress, they were transformed into schistosomula. The schistosomula were placed into a culture medium to which the plant extracts were added. The results obtained indicated that the plant extracts from Berkheya speciosa (Asteraceae), Euclea natalensis (Ebenaceae) and Trichilia emetica (Meliaceae) are lethal to the schistosomula.


Assuntos
Medicinas Tradicionais Africanas , Extratos Vegetais/uso terapêutico , Schistosoma haematobium/efeitos dos fármacos , Esquistossomose/tratamento farmacológico , Animais , Bulinus , Etnofarmacologia , Humanos , Plantas Medicinais , África do Sul
18.
Trop Med Int Health ; 5(6): 423-30, 2000 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-10929142

RESUMO

The aim of studies on plant molluscicides is to complement methods for controlling snails acting as intermediate hosts of schistosomes. We report on the toxic activity of extracts from Jatropha curcas L. (Euphorbiaceae) against snails transmitting Schistosoma mansoni and S. haematobium. We studied different extracts' effects on infectious larvae, cercariae and miracidia of S. mansoni. Compared to aqueous extract, methanol extract showed the highest toxicity against all tested organisms with LC100-values of 25 p.p.m. for cercariae and the snail Biomphalaria glabrata and 1 p.p.m. for the snails Bulinus truncatus and B. natalensis. Attenuation of cercariae leading to reduced infectivity in mice could be achieved in concentrations below those exerting acute toxicity. In view of our results and the ongoing exploitation of J. curcas for other purposes, this plant could become an affordable and effective component of an integrated approach to schistosomiasis control.


Assuntos
Biomphalaria , Bulinus , Euphorbiaceae , Moluscocidas/toxicidade , Schistosoma haematobium/efeitos dos fármacos , Schistosoma mansoni/efeitos dos fármacos , Animais , Crustáceos/efeitos dos fármacos , Larva/efeitos dos fármacos , Camundongos , Extratos Vegetais/toxicidade , Esquistossomose Urinária/prevenção & controle , Esquistossomose mansoni/prevenção & controle
19.
Ann Trop Med Parasitol ; 91(8): 931-7, 1997 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-9579213

RESUMO

The molluscicidal properties of Solanum nigrum L. were tested against three Egyptian snail species (Biomphalaria alexandrina, Bulinus truncatus and Lymnaea natalensis), each an intermediate host of parasites causing human schistosomiasis or fascioliasis. The plant was collected in two regions within Egypt: Fayium and Giza. Snails were exposed for 24 and 48 h, to the dry powdered fruits and leaves or to crude water extracts of the powders, and mortality was recorded. The water extract of the leaves collected in Fayium (FLWE) had the highest molluscicidal activity, with median lethal concentrations (LC50) of 18.6 mg/litre for Bi. alexandrina, 14.5 mg/litre for Bu. truncatus and 17.7 mg/litre for L. natalensis. When Bi. alexandrina infected with Schistosoma mansoni were exposed to FLWE (20 or 25 mg/litre), they shed significantly fewer cercariae than unexposed snails (P < 0.02). The cercaricidal properties of FLWE were directly tested against S. haematobium, S. mansoni and Fasciola gigantica cercariae and a time-concentration relationship was observed; the concentrations needed to kill all cercariae (LC100) within 30 min of exposure were 30 mg/litre for both S. haematobium and S. mansoni and 40 mg/litre for F. gigantica.


Assuntos
Vetores de Doenças , Controle Biológico de Vetores/métodos , Plantas Tóxicas , Schistosoma mansoni/fisiologia , Caramujos/parasitologia , Animais , Armazenamento de Medicamentos , Fasciola/efeitos dos fármacos , Humanos , Inseticidas/farmacologia , Extratos Vegetais/farmacologia , Schistosoma haematobium/efeitos dos fármacos , Schistosoma mansoni/efeitos dos fármacos , Esquistossomose/prevenção & controle , Esquistossomose/transmissão , Caramujos/efeitos dos fármacos
20.
Trop Med Int Health ; 1(2): 221-6, 1996 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-8665388

RESUMO

The effect of endod berry extract against schistosome miracidia has been tested to determine the sensitivity of these organisms to the molluscicide and to see whether miracidia subjected to sublethal doses of the toxicant will be able to infect their specific host snails. Short contact (30 min) LC50 of endod extract with miracidia of Schistosoma mansoni was 8.2 parts per million (p.p.m.) (95% CL 5-13). However, exposure of S. haematobium to sublethal doses of 3 p.p.m. for 30 min or overnight in open air ponds reduced their infectivity 3.5-5.6-fold when compared with controls. It is suggested that the toxicant could be used in low doses at transmission foci to reduce schistosome infection in snails. This could be done by using a controlled release system to apply the toxicant material at such foci where transmission is likely to occur.


Assuntos
Vetores de Doenças , Medicinas Tradicionais Africanas , Moluscocidas , Extratos Vegetais , Schistosoma haematobium/efeitos dos fármacos , Schistosoma mansoni/efeitos dos fármacos , Caramujos/parasitologia , Animais , Avaliação Pré-Clínica de Medicamentos , Interações Ervas-Drogas , Larva , Dose Letal Mediana , Controle de Pragas/métodos , Microbiologia da Água , Zimbábue
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