首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 741 毫秒
1.
Coccidiosis in poultry is caused by protozoan parasites of the genus Eimeria, which is responsible for worldwide economic losses. The methanolic extract of Azadirachta indica (neem) leaves was used in vivo for its pharmacological, antioxidant, and anticoccidial properties. Four groups of mice were investigated. The first group was inoculated only with sterile saline and served as the control group. The second group was treated by oral gavage with neem extract (500 mg/kg) daily for 4 days. The third and fourth groups were infected with 103 sporulated oocysts of Eimeria papillata. The fourth group was also treated once daily with neem extract for 4 days. Paraffin sections from the jejunum as well as jejunal homogenate were prepared for the histopathological and biochemical investigations, respectively. The data showed that mice infected with E. papillata revealed an output of 6.5?×?105?±?29,753 oocysts per gram feces on day?4 postinoculation. This output is significantly decreased to 2.7?×?105?±?37,341 oocysts in neem-treated mice. Infection with E. papillata induced marked histopathological alterations in the jejunum in the form of inflammation, vacuolation of the epithelium, and destruction of some villi. Also, the neem extract greatly diminished body weight loss of infected mice. Moreover, the number of goblet cells stained with Alcian blue within the infected villi was significantly lowered (P?≤?0.05). In addition, E. papillata enhanced lipid peroxidation and nitric oxide production in both serum and jejunum with concomitant reduction in glutathione. Neem induced marked improvements in all of the studied parameters as well as the histopathological features of the jejunum. Our study revealed that neem as a natural product has protective effects against E. papillata-induced coccidiosis.  相似文献   

2.
Here, we investigated the effect of the trace element selenium (Se) on course and outcome of Eimeria-paplllata-induced coccidiosis in mice. Male mice were fed on Se-adequate (0.15 ppm), Se-deficient, and Se-high diets (1.0 ppm) for 6 weeks. Mice were orally infected with 1,000 oocysts. The prepatent period lasts for 3 days, but the course of infections varied. At Se-adequate diet, the maximum fecal output of oocysts amounted to 68,300 ooccysts/g feces on day 5 p.i.. However, fecal shedding of oocysts was accelerated in mice on Se-deficient diet and occurred already on day 4 p.i.. By contrast, maximal shedding is impaired in mice on high-Se diet, which takes place on day 5 p.i., but with a decreased output of only 7,300 oocysts/g feces. Light microscopy reveals that all developmental stages are affected: meronts, micro- and macrogamonts, and developing oocysts are increased in comparison with mice fed on selenium-adequate diet. At high Se, the number of parasitic stages in the jejunum is substantially higher than at Se-deficient diet. Se does not affect the number of jejunal Alcian blue-stained goblet cells. Se deficiency increased the number of apoptotic cells in the jejunum. Substantially increased histological injury scores reveal more injuries in jejunum tissue infected by E. papillata. Our data indicate that high dietary Se exerts potential anticoccidial activity. This may be taken advantage of in control measures towards Eimeriosis as a feed additive, potentially alleviating the need for concomitantly utilized anti-coccidial drugs in the feed.  相似文献   

3.
Accumulating evidence indicates a critical role of microRNAs (miRNAs) in the outcome of diseases. Here, we investigate the effect of garlic on the intestinal miRNA signature of male Balb/c mice during infections with Eimeria papillata. Garlic decreases the intracellular development as evidenced by a lowered fecal output of E. papillata oocysts from 3,150 ± 410 to approximately 1,750 ± 390 oocysts per gram feces on day 4 postinoculation. This anti-coccidial activity of garlic is associated with an inhibition of the E. papillata-induced increases of interferon gamma, inducible nitric oxide synthase, nitrite/nitrate, and malondialdehyde and decrease in glutathione. Moreover, garlic downregulates the E. papillata-induced increases in the expression of the miRNAs miR-1959, miR-203, and miR-21, and it upregulates the expression of the 11 miRNA species miR-142-5P, miR-15A, miR-10A, miR-29B, miR-1902, miR-125A-5P, let-7E, miR-148A, miR-130A, miR-10B, and miR-93, respectively, as revealed by miRXplore microarray technology. Real-time PCR confirms these effects of garlic in the jejunum of E. papillata-infected mice. Our data indicate that the anti-coccidial activity of garlic is associated with specific changes in the miRNA signature of the mouse jejunum, the target site of E. papillata. These changes may reflect an involvement of miRNAs in garlic-activated pathways to reduce and/or to repair E. papillata-induced tissue injuries.  相似文献   

4.
There is no effective natural alternative control for gastrointestinal nematodes (GIN) of small ruminants, with Haemonchus contortus being the most economically important GIN. Despite frequent reports of multidrug-resistant GIN, there is no new commercial anthelmintic to substitute failing ones. Although trematocidal activity of artemisinin analogs has been reported in sheep, neither artemisinin nor its plant source (Artemisia annua) has been evaluated for anthelmintic activity in ruminants. This study evaluated the anthelmintic activity of A. annua crude extracts in vitro and compared the most effective extract with artemisinin in sheep naturally infected with H. contortus. A. annua leaves extracted with water, aqueous 0.1 % sodium bicarbonate, dichloromethane, and ethanol were evaluated in vitro by the egg hatch test (EHT) and with the bicarbonate extract only for the larval development test (LDT) using H. contortus. The A. annua water, sodium bicarbonate (SBE), ethanol, and dichloromethane extracts tested in vitro contained 0.3, 0.6, 4.4, and 9.8 % of artemisinin, respectively. The sodium bicarbonate extract resulted in the lowest LC99 in the EHT (1.27 μg/mL) and in a LC99 of 23.8 μg/mL in the LDT. Following in vitro results, the SBE (2 g/kg body weight (BW)) and artemisinin (100 mg/kg BW) were evaluated as a single oral dose in naturally infected Santa Inês sheep. Speciation from stool cultures established that 84–91 % of GIN were H. contortus, 8.4–15.6 % were Trichostrongylus sp., and 0.3–0.7 % were Oesophagostomum sp. Packed-cell volume and eggs per gram (EPG) of feces were used to test treatment efficacy. The SBE tested in vivo contained no artemisinin, but had a high antioxidant capacity of 2,295 μmol of Trolox equivalents/g. Sheep dosed with artemisinin had maximum feces concentrations 24 h after treatment (126.5 μg/g artemisinin), which sharply decreased at 36 h. By day 15, only levamisole-treated sheep had a significant decrease of 97 % in EPG. Artemisinin-treated and SBE-treated sheep had nonsignificant EPG reductions of 28 and 19 %, respectively, while sheep in infected/untreated group had an average EPG increase of 95 %. Sheep treated with artemisinin and A. annua SBE maintained blood hematocrits throughout the experiment, while untreated/infected controls had a significant reduction in hematocrit. This is the first time oral dose of artemisinin and an aqueous extract of A. annua are evaluated as anthelmintic in sheep. Although oral dose of artemisinin and SBE, at single doses, were ineffective natural anthelmintics, artemisinin analogs with better bioavailability than artemisinin should be tested in vivo, through different routes and in multiple doses. The maintenance of hematocrit provided by artemisinin and A. annua extract and the high antioxidant capacity of the latter suggest that they could be combined with commercial anthelmintics to improve the well-being of infected animals and to evaluate potential synergism.  相似文献   

5.
The aim of this study was to investigate the in vitro and in vivo efficacies of chemotherapy employing albendazole liposome (L-ABZ), Huaier aqueous extract, and a Huaier aqueous extract/L-ABZ combination against Echinococcus granulosus. Protoscolices of E. granulosus were incubated in vitro with the two drugs, either separately or in combination, at the following final concentrations: 2 mg/mL Huaier aqueous extract, 10 μg/mL L-ABZ, and 2 mg/mL Huaier aqueous extract + 10 μg/mL?L-ABZ. Huaier aqueous extract and L-ABZ displayed slower protoscolicidal activity when applied separately than when used in combination. The maximum protoscolicidal effect was found with the combination Huaier aqueous extract + L-ABZ. Despite the low Huaier aqueous extract + L-ABZ concentrations used, protoscolex viability dropped rapidly. In vivo studies were performed on mice injected with protoscolices of E. granulosus. Huaier aqueous extract and L-ABZ were administered three times a week for a period of 4 months by the oral route. Huaier aqueous extract in E. granulosus-infected mice was effective. Combined application of both drugs did increase the treatment efficacy. In conclusion, the outcomes obtained clearly demonstrated that in vitro and in vivo treatment with Huaier aqueous extract and L-ABZ is effective against E. granulosus.  相似文献   

6.
Coccidiosis is a common infectious disease in poultry causing major economic losses. Here, we investigated the effect of Khodary date fruit aqueous extract (4 ml/kg) on the outcome of coccidiosis caused by Eimeria papillata in Swiss Albino mice. Date fruit extract was able to decrease the intracellular development by lowering the faecal output of E. papillata oocysts from 8.7?±?0.5?×?10(3) to 6.6?±?0.4?×?10(3) oocysts per gram faeces. Also, date extract caused a great diminish in body weight of infected mice from 19.3 to 3.2?%. The number of parasitic stages in the intestinal villi of the infected mice was reduced to about 52?% after treatment with date extract. The infection was associated with marked histopathological lesions of the murine jejunum in the form of inflammation, vacuolation of the epithelium, and destruction of some villi. Also, the number of goblet cells within the infected villi was significantly lowered (P?≤?0.05). These changes lead to an oxidative damage of the infected tissue. Moreover, infection induced a disturbance in both protein and carbohydrate content in the infected mice. Treatment of mice with date extract could improve the above-studied parameters. On the basis of the above results it can be hypothesized that date fruit can protect against coccidiosis-induced infection, this hypothesis can be revealed by the anti-inflammatory activity of date protecting host tissue from injuries induced by the parasite, and hence it is recommended to be used as an excellent food additive.  相似文献   

7.
With the aim of finding natural anthelmintic agents against Dactylogyrus intermedius (Monogenea) in goldfish (Carassius auratus), 26 plants were screened for antiparasitic properties using in vivo anthelmintic efficacy assay. The results showed that Caesalpinia sappan, Lysima chiachristinae, Cuscuta chinensis, Artemisia argyi, and Eupatorium fortunei were found to have 100 % anthelmintic efficacy at 125, 150, 225, 300, and 500 mg L?1 after 48 h of exposure. Crude extract of the five plants were further partitioned with petroleum ether, chloroform, ethyl acetate, methanol, and water to obtain anthelmintically active fractions with various polarity. Among these fractions tested, the ethyl acetate extract of L. chiachristinae was found to be the most effective with a 50 % effective concentration (EC50) value of 5.1 mg/L after 48 h of exposure. This was followed by ethyl acetate extract of C. chinensis (48 h-EC50?=?8.5 mg L?1), chloroform extracts of C. sappan (48 h-EC50?=?15.6 mg L?1), methanol extract of C. chinensis (48 h-EC50?=?15.9 mg L?1), and chloroform and petroleum ether extract of L. chiachristinae (EC50 values of 17.2 and 21.1 mg/L, respectively), suggesting that these plants, as well as the active fractions, provide potential sources of botanic drugs for the control of D. intermedius in aquaculture.  相似文献   

8.
This study was aimed to investigate the efficacy of Thunbergia laurifolia leaf extract to protect hemolysis in mice infected with Plasmodium berghei. Aqueous leaf extract of T. laurifolia was freshly prepared, and total polyphenol was then measured using Folin-Ciocalteu reagent method. For in vivo test, ICR mice were given intraperitoneally with this extract (1,000 mg/kg) once a day for four consecutive days and subsequently inoculated with 1?×?106 parasitized erythrocytes of P. berghei ANKA by intraperitoneal injection for 8 days. The results showed that hemolysis was inhibited as indicated by %hematocrit (%Hct) which was normal in infected mice treated with T. laurifolia extract. Untreated and pyrimethamine-treated controls showed decreasing %Hct. Moreover, no any toxic signs were observed in normal mice treated with this extract. We conclude that T. laurifolia leaf extract clearly protects hemolysis during P. berghei infection in mice.  相似文献   

9.
An Eimeria intestinalis isolated from a rabbit in China was first identified by amplifying the 18S small subunit (SSU) ribosomal RNA gene. The size of the amplified fragment was 1521 bp. The 18S SSU RNA gene of the E. intestinalis isolate shared 99 % sequence identity with E. intestinalis isolates from France and the Czech Republic, with 100 and 96 % coverage, respectively. Then, the pathogenicity and immunogenicity of the E. intestinalis isolate were evaluated in specific pathogen free (SPF) rabbits. In the pathogenicity assay, SPF rabbits in four groups were infected with 5?×?103, 5?×?104, 5?×?105, and 0 sporulated oocysts, respectively. Clinical signs including diarrhoea, constipation, loss of appetite, and reduction of body weight gain were observed in rabbits inoculated with 5?×?104 and 5?×?105 oocysts. And one rabbit (25 %) inoculated with 5?×?105 oocysts died 15 days after the inoculation. In the immunogenicity assay, SPF rabbits in five groups (named B1, B2, B3, B4, and B5) were immunised with 5?×?101, 5?×?102, 5?×?103, 0, and 0 sporulated oocysts, respectively. All rabbits but the B5 group were challenged with 1?×?106 oocysts. After the challenge, no or slight clinical signs were seen in rabbits of the B2 and B3 groups. Compared with the control, a 69.6 and 84.5 % reduction of oocyst output was observed in the B2 and B3 groups, respectively. The body weight gain of the two groups was obviously higher than that of the challenge control group. All the results show that the E. intestinalis isolate has low virulence but immunogenicity in rabbit.  相似文献   

10.
Intestinal helmintic infection, continue to be a cause of major concern in several parts of the world, particularly in the developing nations. The use of plant extracts to control poultry helminths is increasing in different rearing systems. The anthelmintic activity of ginger and curcumin was studied on the nematode Ascaridia galli. In vitro and in vivo studies were allocated. Live parasites for in vitro studies were collected from the intestine of naturally infected chickens. Some living worms were incubated at 37 °C in media containing ginger at three concentration levels (25, 50, and 100 mg/ml), and others were incubated in media containing curcumin at the same concentration levels. Another living worm group was incubated in media containing albendazole at a dose of 7.5 mg/ml. The extracts' efficacy was exhibited in a concentration–time-dependent manner mainly at 100 mg/ml and after 48 h. The in vivo study takes place on experimentally infected chickens. Group of infected chickens was treated with ginger extract at dose of 100 mg, another group was treated with curcumin extract at dose of 100 mg, and a third group was treated with albendazole at dose of 7.5 mg. In vivo study of ginger and curcumin recorded lower mortality rates than the in vitro study. It is concluded that ginger and curcumin extracts have potential anthelmintic properties against A. galli. Ginger in all concentrations used exhibited a higher death rate observed than curcumin. Their wormicidal effect is concentration–time dependent.  相似文献   

11.
In order to search for new products that display antimalarial and immunomodulatory mechanisms that complement direct antiparasitic activity, a set of in vitro and in vivo experiments were designed to evaluate the effect of Nyctanthes arbor-tristis in Plasmodium berghei infected mice. Three extracts of N. arbor-tristis leaves from varying concentrations of alcohol and water were considered for their potential to suppress expression of pro-inflammatory mediators from macrophages primed with lipopolysaccharide. The ethanolic extract, which lowered the pro-inflammatory mediators [tumour necrosis factor (TNF), 13.52–55.83 %; interleukin-6 (IL-6), 0–17.29 %; and NO, 39.37–81.63 %], was selected to be examined in malaria (P. berghei) infected mice. Corroborating the in vitro results, it was observed that the extract could normalise the TNF (78 %) and IL-6 (70.35 %) optimally at 1 g/kg, thus retarding the pathological process in infected mice and increasing the mean survival time from 10.6 to 15.6 days. There were no signs of toxicity in the acute oral toxicity test up to 2 g/kg. 1H NMR of the biologically active extract was obtained to ensure the presence of the compound of interest, i.e., iridoid glycoside. The quality and the reproducibility of results were ensured by means of achieving characteristic high-performance liquid chromatography fingerprint of the extract.  相似文献   

12.
The purpose of this study was to evaluate the therapeutic effect of chymostatin, as an elastase inhibitor, in mice with invasive aspergillosis. Two Aspergillus fumigatus (A. fumigatus) isolates obtained from animals (bovine mastitis and avian endophthalmitis) along with elastase-producing A. fumigatus ATCC 26933 were inoculated to seven mice groups according to the protocol. The induction of aspergillosis was confirmed by tissue cultures as well as histopathological examination. Chymostatin, as an elastase inhibitor, was used in treating the infected animals at doses of 50, 100, and 200 μM in four different times. There was no mortality in mice group 6 (mice treated with elastase-producing A. fumigatus ATCC 26933?+?200 μM chymostatin). The mortality rate was calculated approximately 50 % in mice infected with elastase-producing A. fumigatus (group 2). The highest colony forming units was observed in the kidney (35.3 %) and the lowest in the liver (5.9 %). Moreover, Aspergillus hyphae were observed in different tissues obtained from died mice in all groups except group 6. The results showed that chymostatin at a dose of 200 μM could be useful as a feasible replacement agent for the treatment of invasive aspergillosis.  相似文献   

13.
Traditional medicines have been used to treat malaria for thousands of years and are the source of artemisinin and quinine derivatives. With the increasing levels of drug resistance, the high cost of artemisisnin-based combination therapies, and fake antimalarials drugs, traditional medicine have become an important and sustainable source of malaria treatment. For the benefit of those who use traditional medicine to treat malaria, there is an urgent need to study the efficacy and toxicity of herbal remedies. Hintonia latiflora stem bark infusions are use in Mexican traditional medicine to treat malaria, diabetes, and gastrointestinal diseases. Its efficacy in the treatment of complicated malaria and its ability to generate DNA damage to the host is not fully evaluated. In our search for antimalarial natural products, in the present study, we tested the efficacy of H. latiflora stem bark methanolic extract (HlMeOHe) in CD1 male mice infected with lethal Plasmodium yoelii yoelii and its in vivo cytotoxicity and genotoxicity. To assess the antimalarial activity, the extract was evaluated in a 4-day test scheme in oral doses of 1,200, 600, and 300 mg/kg prior acute toxicity test; oral chloroquine (15 mg/kg) was used as positive control. The ability of 1,200 mg/kg of HlMeOHe to induce cytotoxicity and DNA damage in the peripheral blood of mice was assessed using a fluorochrome-mediated viability test and the micronucleus (MN) assay; N-ethyl-N-nitrosourea (ENU) was used as a positive control. HlMeOHe median acute toxicity (LD50) was 2,783.71 mg/kg and LD10 was 1,293.76 mg/kg (taken as the highest work dose). Plasmodium yoelii yoelii-infected mice in the untreated control group died between 6 and 7 days post-infection (PI) with parasitemia over 70 %. Even though mice treated with 600 and 300 mg/kg showed a chemosuppression percentage of total parasitemia of 99.23 and 23.66, respectively, animals in both groups died 6 to 7 days PI with parasitemia over 45 %. A 4-day dosage of 1,200 mg/kg of the extract showed, in the P. yoelii yoelii-infected mice, a 100 % chemosuppression of total parasitemia on 5 days PI and a 23 days survival time with a mean parasitemia of 23.6 % at the date of death. Only mice treated with chloroquine survived until the end of the experiment. Cell viability was not affected. The average number of micronuclei in the treated mice increased significantly (P?<?0.05) to 4.8 MN when compared with the untreated control group (0.9 MN). The results obtained in this study showed that the infection outcome of P. yoelii yoelii-infected mice is affected by HlMeOHe. Although a concentration of 1,200 mg/kg of HlMeOHe is suitable to use in the treatment of malaria fever, slowed down the parasite replication, retarded the patency time, and increased the infected P. yoelii yoelii mice survival time, its chemical composition should be studied in detail in order to reduce its genotoxic potential.  相似文献   

14.
Leishmaniasis is one of the most important diseases transmitted by arthropod. This disease is present in 88 countries. Approximately 400 million people are at risk, and 12 million are involved. We aimed to examine the application of ethanolic extract of the root bark of Berberis vulgaris L. for treatment of mice infected with cutaneous leishmaniasis. At first, 40 BALB/c mice were infected to Leishmania major promastigotes and were divided in two groups A and B. Then, each of A and B groups were divided to two subgroups. Mice from subgroup A1 were treated with 10 % root bark alcoholic extract, and mice from subgroup A2 were treated with only alcohol (control). Mice from subgroup B1 were treated with 20 % root bark alcoholic extract, and mice from subgroup B2 were treated with only alcohol (control). The 90 % recovery was found in the mice treated with 20 % root bark extract, and 55 % recovery was found with 10 % root bark extract, but in the control group, 0 % recovery was found. The results of our study showed that the lotion of root bark extract has good suppression effects on parasites. Therefore, it might be a pro for developing new antileishmanial drugs.  相似文献   

15.
The present study was performed to explore the efficacy of the commercial anticoccidial vaccine (Coccivac B®) in broiler chickens using five field strains of Eimeria tenella that were isolated from five provinces in Egypt. This study also analyzed the ITS-1-rDNA sequence of these five strains and its corresponding sequence in the vaccine. In a floor pen experiment, 216 one-day-old commercial broiler chicks were classified into vaccinated and non-vaccinated groups. Each main group was classified into six subgroups. The chicks were challenged on the 28th day of age with 104 sporulated oocysts of one of the five field strains of E. tenella. Our results indicated that Coccivac B® produced variable degrees of protection in the birds infected with the five different strains of E. tenella. Aligning the ITS-1 sequences from the five strains with the ITS-1 sequence of E. tenella from the vaccine revealed 96 % sequence similarity with the Kafer El-Sheikh strain, 94 % with the Gharbia strain, 90 % with the Alexandria strain, and 78 % with the Matrouh and Behera strains. While interesting, these similarity values were not useful for predicting the protection conferred by the vaccine against the five field isolates. However, based on the data reported here, we can conclude that Coccivac B® produced variable degrees of protection in the birds infected with the five different strains of E. tenella  相似文献   

16.
Terminalia avicennioides Guill. & Perr. (Combretaceae) is used traditionally to treat malaria in Nigeria. To establish its efficacy, methanolic extract of T. avicennioides bark was investigated for antimalarial activity against Plasmodium berghei (NK-65) in mice. Twenty-five mice in five groups were used for this study. Group 1 was uninfected normal control. Twenty mice infected with P. berghei were grouped as untreated negative control (group 2), 5 mg/kg b.w. p.o. artesunate-treated positive control (group 3), and 100 and 200 mg/kg b.w. p.o. T. avicennioides-treated infected mice (groups 4 and 5, respectively). Four-day suppressive effects on P. berghei and hematological and oxidative statuses of the mice were assessed. Suppression of parasitemia by artesunate and methanolic extract of T. avicennioides (at 100 and 200 mg/kg b.w.) after 1 day of treatment was 10, 18, and 11 % respectively; at day 5, the level of suppression was 77, 82, and 84 % respectively. P. berghei infection decreased hemoglobin, red blood cell, and lymphocyte counts and increased neutrophil count; artesunate and medicinal plant treatment restored these parameters to normal control levels. Also, artesunate and medicinal plant treatment of infected mice significantly (p?<?0.05) increased serum and liver superoxide dismutase activities and significantly (p?<?0.05) reduced serum malondialdehyde concentration compared to untreated infected mice. The antimalarial effect of T. avicennioides is comparable to that of artesunate. The restoration of oxidative and hematological statuses, to normal values by T. avicennioides, may provide better protection against the malaria severity and complications.  相似文献   

17.
Cattle feces are the environmental vehicle for the zoonotic Cryptosporidium oocysts, but there are drawbacks associated with reliability of the existing methods for the detection of oocysts in the feces. Quantification of the immunomagnetic bead separation (IMS) coupled with real-time TaqMan PCR (qPCR) was accomplished by comparing the fluorescence signals obtained from the calf fecal samples of Cryptosporidium parvum oocysts with those obtained from standard dilutions of C. parvum oocysts. TaqMan qPCR assays were developed for the detection of C. parvum based on 18S rDNA gene. This IMS-qPCR assay allowed a reliable quantification of C. parvum oocysts over seven orders of magnitude with a baseline sensitivity of 8.7 oocysts. The newly developed IMS-qPCR technique proved specific as confirmed by negative reactivity against a wide panel of non-parvum Cryptosporidium oocysts. As a field application, experimentally infected calves (15 infected and 9 non-infected) were screened for oocysts shedding on 16, 18, and 21 days postinfection. Acid-fast staining microscopy of infected calves revealed oocysts in the feces of 11, 7, and 4 calves, respectively, compared to 15, 15, and 12 in case of screening by IMS-qPCR. Taken together, the proposed IMS-qPCR method significantly improved the diagnostic capacity for C. parvum infection in calves, making the technique a useful, sensitive, reliable, and time-saving.  相似文献   

18.
19.
The crude methanol extracts of leaf, stem bark, root bark and stem bark fractions of Trichilia megalantha (Meliaceae) were screened for in vivo antimalarial activities in mice against a chloroquine resistant Plasmodium berghei berghei ANKA clone using the 4-day suppressive test procedure. Chloroquine diphosphate was used as the positive control. The extracts demonstrated intrinsic antimalarial property. Of all the seven extracts studied, the stem bark gave the highest activity. At 200 mg/kg of mouse, the stem bark extract had complete suppression of parasite growth (100 %). Least activity was observed for the leaf extract, while the root bark had a parasite suppression of 98.4 % at 800 mg/kg comparable to that of Chloroquine. Percentage suppression of parasite growth on day 4 post-infection ranged from 3.1 to 96.1 % in mice infected with P. berghei and treated with extracts and fractions of T. megalantha when compared with chloroquine diphosphate, the standard reference drug which had a chemosuppression of 96.2 %. At 400 mg/kg, the stem bark chloroform fraction was the most active fraction with 89.1 % parasite growth suppression followed by the ethyl acetate fraction (76.4 %), hexane soluble fraction (54.8 %) and methanol fraction (20.5 %). The mean survival time of mice that received extract ranged from 8.75?±?0.65 to 26.0?±?1.2 days (increased as the dose increases to 800 mg/kg), which was statistically significant, except the lowest dose (100 mg/kg) compared to the negative control group mice (9.45?±?0.6 days). The animals that were treated with Chloroquine had mean survival time of 23.5?±?1.2 days  相似文献   

20.
Blackwater fever (BWF) is the term used to designate the occurrence of hemoglobin pigments in the urine of patients infected with malaria parasites. BWF is more often associated with Plasmodium falciparum infection in man. The pathogenesis of BWF has not been explained satisfactorily. In the present study, the clinical and pathological observations made upon CD1 mice infected with Plasmodium yoelii yoelii lethal strain with clinical signs of hemoglobinuria and acute renal failure were evaluated. From the 40 P. yoelii yoelii-infected mice, 14 presented hemoglobinuria. In the observations, it was emphasized that hemoglobinuria occurred in the animals 1–2 days before they die. At 6 days post-infection, infected hemoglobinuric mice (HM) exhibited clinical signs such as dark red urine, apnea, and evident oliguria and hematuria; urine microscopical examination showed very few red blood cells. The entire non hemoglobinuric infected mice had a high parasitemia preceding the time of death, while the HM parasitemia was just detectable. In HM, marked hepatosplenomegaly, anemia, and renal and hepatic dysfunction were observed with the blood chemistry analysis at 6 days post-infection. Severe renal lesions were demonstrated in histopathological and scanning electron microscopy samples. Occlusion and necrosis of convoluted tubules were the main lesions found. The conditions required for the experimental production of hemoglobinuria in CD1 mouse infected by P. yoelii yoelii is still unknown. The clinical picture of a BWF, like in our rodents, was produced exclusively by the interaction between the parasite and its host. Results showed that hemoglobinuria in CD1 mice infected with P. yoelii yoelii and BWF in man infected with P. falciparum are similar in their pathogenesis.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号