Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “PLASMODIUM”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 829 records · Page 46Linked to original sources
PubMed2001

[Gene typing of merozoite surface protein 1 of Plasmodium falciparum isolates from Hainan Province].

OBJECTIVE: To identify the genotype of merozoite surface protein 1 (MSP1) of Plasmodium falciparum isolates from Hainan Province. METHODS: Nested PCR was applied to amplify the MSP1 of Blocks 2 and 3 Plasmodium falciparum isolates from Hainan Province. Two allelic family representative gene fragments were sequenced. RESULTS: From 36 out of 39 blood samples from Plasmodium falciparum patients, 44 gene fragments of blocks 2 and 3 of the MSP1 were amplified, of which the MAD20-type allele was dominant(75%). followed by K1-type allele. No RO33-type allele was found. The mixed infection rate of the two different allelic type was 19.4%. Sequence analysis showed that the sequences of MAD20- and K1-type isolates from Hainan Province were highly homologous to that of the MAD20 and K1 allelic prototypes. CONCLUSION: Two principal allelic types of MSP1 gene, MAD20- and K1-type, exist in malaria endemic areas in Hainan Province, the MAD20-type being the dominant.

Alleles↗
PubMed2002

In-vitro sensitivity of Plasmodium falciparum to chloroquine, halofantrine, mefloquine and quinine in Madagascar.

OBJECTIVE: To determine how sensitive Plasmodium falciparum is to the major antimalarial drugs in Madagascar. DESIGN: Assessment of Plasmodium falciparum isolates sensitivity to antimalarials, by use of the in-vitro radioisotope method. SETTING: Ankazobe and Saharevo in the foothill areas; and Toamasina and Tolagnaro in the coastal areas (between January 1998 and November 1999). SUBJECTS: Primary Plasmodium falciparum isolates from patients with uncomplicated malaria attack. RESULTS: Between January 1998 and November 1999, of the 293 in-vitro tests done with at least one antimalarial, 70% (205/293) were interpretable. As there was no significant difference between results from the four study sites, the data have been expressed as a whole. All of the successfully tested isolates were sensitive to halofantrine (n = 56) and to quinine (n = 199), 5.8% (12/205) of the isolates were resistant to chloroquine and 2% (4/199) to mefloquine. The geometric mean IC50 was 0.3 microg/L for halofantrine (95% CI = 0.1-0.4 microg/L); 9.4 microg/L for chloroquine (95% CI = 7.3-10.8 microg/L); 3.8 microg/L for mefloquine (95% CI = 3.3-4.3 microg/L); and 26.8 microg/L for quinine (95% CI = 24.3-29.4 microg/L). The low positive correlation found between halofantrine and chloroquine IC50s (n = 56; r = 0.41, P = 0.002) suggests a risk of cross-resistance between these two drugs. CONCLUSION: The degree and frequency of chloroquine resistance in-vitro is stationary in Madagascar compared to previous results during the last decade. The in-vitro sensitivity of P. falciparum to quinine, mefloquine and halofantrine encourages the use of these drugs as alternative in case of chloroquine treatment failure. Nevertheless, it is important to maintain and to extend malaria and drug sensitivity surveillance in Madagascar.

Animals↗
PubMed2003

[Study on the relationship between intracellular free calcium and melanization in oocysts of Plasmodium yoelii].

OBJECTIVE: To study the change of intracellular free Ca2+ in the oocyst when it melanized and to find out the relationship between the melanized oocyst and its intracellular level of free Ca2+ in a Plasmodium-refractory strain of Anopheles dirus. METHODS: The distribution and experimental condition of the intracellular free Ca2+ in oocyst of Plasmodium yoelii was measured with Ca2+ sensitive dye Fluo-3/AM and Pluronic F-127 under confocal laser scanning microscope (CLSM) at different time. RESULTS: The best load condition was that the oocysts were incubated in 3 mumol/ml Fluo-3/AM adding 1 microliter/ml 25% Pluronic F-127 for 60 min at 37 degrees C. Fluorescent imaging of oocysts was affected by an increase or decrease of the concentration of Fluo-3/Am and incubation time. The distribution of intracellular free Ca2+ was heterogeneous in the oocysts. The mean value of Ca2+ in the mature oocysts was (137.15 +/- 7.02) nmol/L (X +/- S) but was (18.44 +/- 1.75) nmol/L in melanized oocysts with Ca2+ sedimentation in the wall of oocyst. CONCLUSION: The results suggest that the level of the intracellular free Ca2+ in oocyst decreased and excreted during its melanization in a Plasmodium-refractory anopheline mosquito species.

Animals↗
PubMed2001

[Establishment of antigen presenting cells model of Plasmodium falciparum cytotoxic T lymphocyte single epitope vaccine].

OBJECTIVE: To construct plasmodium falciparum cytotoxic T lymphocyte (CTL) single epitope vaccine and establish antigen presenting cells model. METHODS: Gene encoding HLA-A11 restricted plasmodium falciparum CTL epitope (VTCGNGIQVR), which was in high frequency among Chinese population, was chosen and cloned into an eukaryotic expressing vector to form CTL single epitope vaccine: pcDNA3.1/beta 2m/A11. This plasmid was transfected and expressed in cell lines bearing only HLA-A11 molecule. The expressions of HLA class I molecules were accessed by flow cytometry. RESULTS: The CTL single epitope was expressed in HLA-A11 cell lines and an obviously increased expressions of HLA class were detected in the transfected cell lines, and evaluated as mean channel number of fluorescence by flow cytometry (P < 0.05). CONCLUSIONS: CTL single epitope expressing plasmid was constructed and the antigen presenting cells model was established. It was demonstrated that plasmodium falciparum CTL single epitope was effectively processed and expressed. Our work suggested the single-epitope vaccine might provide protection for populations which containing HLA-A11 background.

Animals↗
PubMed1992

Monocyte tissue factor expression induced by Plasmodium falciparum-infected erythrocytes.

Monocytes are active elements of the host response against Plasmodium falciparum. They are able to express tissue factor and trigger the extrinsic pathway of blood coagulation the activation of which remained unclear in malaria. Our aim was to assess the tissue factor expression of purified blood monocytes stimulated by cultured Plasmodium falciparum-infected erythrocytes. Malaria parasite induced an early generation of tissue factor with a peak between 8 and 12 h of stimulation. Maximum expression was observed for parasitemia ranging from 1 to 2%. Plasmodium falciparum culture supernatants had the same effect showing the existence of a soluble factor able to induce the tissue factor expression. These data, demonstrating an activation of the tissue factor pathway by the malaria parasite, emphasize thrombin generation. Therefore, thrombin could participate in malaria pathology either in the microcirculatory blockade via platelet and fibrinogen activation or as a mitotic.

Animals↗
PubMed2004

[Preliminary study on regulable DNA vaccines against Plasmodium falciparum].

AIM: To construct regulable DNA vaccine against Plasmodium falciparum by using tetracycline(Tet) regulable system. METHODS: Eukaryotic expression vectors pTL-8/apical membrane antigen 1 (AMA-1) (tTA) and pTL-8/AMA-1(rtTA) gene which express trans-activator (tTA) or reverse trans-activator(rtTA), respectively, and AMA-1 gene of Plasmodium falciparum were constructed. BALB/c mice were immunized with these plasmids and doxycycline (dox) was administered to regulate the expression of AMA-1. For some mice immunized with pTL-8/AMA-1(rtTA), pUHS6-1, a plasmid containing trans-silencer (tTS) to suppress basal expression of AMA-1 from pTL-8/AMA-1(rtTA), was injected into these mice together with pTL-8/AMA-1(rtTA). The sera of the mice were isolated at 2,4,6 and 8 weeks post-immunization and the antibodies specific to AMA-1 were measured by ELISA. RESULTS: pTL-8/AMA-1 and pTL-8/AMA-1(rtTA) were constructed successfully. The mice immunized by pTL-8/AMA-1(tTA) with dox or by pTL-8/AMA-1(rtTA) without dox (at these conditions, AMA-1 was expressed at basal level)developed significant antibodies against AMA-1. Mice immunized by pTL-8/AMA-1(rtTA) and pUHS6-1 without dox did not develop significantly antibodies against AMA-1. In contrast, the mice immunized by pTL-8/AMA-1(rtTA) and pUHS6-1 with dox produced high level of antibodies. CONCLUSION: pTL-8/AMA-1(rtTA) combined with pUHS6-1 is a good regulable DNA vaccine candidate against Plasmodium falciparum.

Animals↗
PubMed2004

Serum malondialdehyde levels in patients infected with Plasmodium vivax.

Malondialdehyde, a lipid peroxide, may be used as an indicator of oxidative stress. This study investigated the oxidative stress hypothesis in patients infected with Plasmodium vivax. Serum malondialdehyde (MDA) concentration activity was measured in 87 patients. Scores were obtained for the patients and 60 seronegative healthy controls matched for age and gender. The difference between MDA levels of patients infected with Plasmodium vivax and the control group was statistically significant both for females (p < 0.001) and males (p < 0.001). In the patient and control group, no correlation was found between age and malondialdehyde levels (p > 0.05) in both females and males. In addition, no significant correlation could be found between MDA levels of both females and males for patients and control group (p > 0.05). MDA levels were increased in the patients infected with Plasmodium vivax.

Adolescent↗
PubMed2004

IgG(4) Pf NPNA-1 a human anti-Plasmodium falciparum sporozoite monoclonal antibody cloned from a protected individual inhibits parasite invasion of hepatocytes.

Malaria is one of the world's most devastating diseases, and Plasmodium falciparum (Pf) causes significant mortalities particularly in Sub-Saharan Africa. The rise and spread of multi-drug resistant strains of the parasite has coincided with an era of increased travel to malaria endemic regions. In the absence of an effective vaccine against malaria it may be possible to utilize human monoclonal antibodies against the stage transmitted by mosquito bites (sporozoites) as a prophylactic to prevent infection. We report the characterization of an engineered human IgG(4) monoclonal antibody against Pf sporozoite cloned from a protected individual recognized the sporozoite surface and inhibited sporozoite invasion of human hepatocytes in vitro. The fully human monoclonal antibody PfNPNA-1 IgG(4) against (NPNA)(3) specifically labels Plasmodium falciparum in an IFA. This antibody also inhibits Plasmodium falciparum sporozoite invasion of human hepatocytes HepG2-A16 in a dose dependent manner in an in vitro assay. PfNPNA-1 IgG(4) is a promising candidate for evaluation for the prevention of malaria.

Animals↗
PubMed2005

Large sequence heterogeneity of the small subunit ribosomal RNA gene of Plasmodium ovale in cambodia.

Plasmodium ovale malaria has been reported in various countries in southeast Asia, but never in Cambodia. Using a species-specific polymerase chain reaction (PCR) targeting the small subunit (SSU) ribosomal RNA (rRNA) gene, we detected P. ovale in nearly 4% of the inhabitants of a northeastern Cambodian village. Plasmodium ovale was associated with at least one other Plasmodium species, and two quadruple infections were detected. The diagnosis was confirmed by microscopy and by SSU rRNA PCR product sequencing. The sequences shared 96-99% identity with published sequences, and displayed a substantial heterogeneity with 2-4 different haplotypes per sample. Nine distinct SSU rRNA haplotypes were identified, including seven novel variants. Phylogenetic analysis showed two major genetic clusters, suggesting amplification of two distinct gene sets and/or P. ovale variants from each sample. Our data indicate that P. ovale was overlooked in Cambodia until now, and call for the implementation of larger prevalence surveys and accurate diagnosis methods in this country.

Animals↗
PubMed2005

The presence of Plasmodium falciparum gametocytes in human blood increases the gravidity of Anopheles gambiae mosquitoes.

We conducted a field study in an area of endemic malaria transmission in western Kenya to determine whether mosquitoes that feed on gametocyte-infected blood but do not become infected have reduced or enhanced fecundity in comparison to mosquitoes fed on uninfected blood. Fifteen paired membrane-feeding experiments were conducted in which two strains of Anopheles gambiae mosquitoes were simultaneously fed on either Plasmodium falciparum-infected blood from children or uninfected control blood from adults. The presence of noninfecting gametocytes in blood increased the probability that An. gambiae would produce eggs after one blood meal by sixfold (odds ratio for control relative to infected blood group 0.16; 95% CI 0.10-0.23). This result could not be explained by variation in blood meal size or hemoglobin content between hosts. When children cleared their infections, the difference in gravidity between mosquitoes fed on their blood and uninfected adults disappeared, suggesting this phenomenon is due to the presence of Plasmodium gametocytes in blood and not to host-specific factors such as age. This result was observed in two mosquito strains that differ in their innate fecundity, suggesting it may apply generally. To our knowledge, this is the first time that Plasmodium has been implicated as enhancing vector gravidity.

Adult↗
PubMed2006

In vitro potentiation of antimalarial activities by daphnetin derivatives against Plasmodium falciparum.

OBJECTIVE: To screen the antimalarial compounds of daphnetin derivatives against Plasmodium falciparum in vitro. METHOD: Plasmodium faciparum (FCC1) was cultured in vitro by a modified method of Trager and Jensen. Antimalarial compounds were screened by microscopy-based assay and microfluorimetric method. RESULTS: DA79 and DA78 showed potent antimalarial activity against Plasmodium falciparum cultured in vitro. CONCLUSION: Though the relationship between the structures of daphnetin derivatives and their antimalarial activities has not been clarified yet, this study may provide a new direction for discovery of more potential antimalarial compounds.

Animals↗
PubMedDate not supplied

[A case of Plasmodium falciparum malaria in a nurse].

A case of plasmodium falciparum malaria in a 21-year old nurse, who never left Poland, was described. Malaria was confirmed by parasitological examination of peripheral blood smears in which 20% of erythrocytes infected with Plasmodium falciparum were found. The course of the disease was very severe but the patient survived. The only possibility of infection must have been through skin lesion on the nurse's hand during obtaining blood from the patient infected with Plasmodium falciparum.

Adult↗
PubMed1989

Effects of pyran copolymer on host resistance of mice to Plasmodium yoelii.

Female B6C3F1 mice treated with 25 mg/kg pyran intravenously (i.v.) on days -4 and -3 were more susceptible to nonlethal Plasmodium yoelii 17XNL or lethal Plasmodium berghei ATCC-30090 than untreated mice or mice treated intraperitoneally (i.p.). Female B6C3F1 mice treated with pyran i.p. displayed enhanced resistance to Listeria monocytogenes as compared to untreated mice or mice given pyran i.v. Peritoneal exudate cells (PEC) primed by pyran i.p. possessed enhanced ability to kill Listeria but impaired ability to destroy Plasmodium. Phagocytosis of Covaspheres by PEC was greater for mice given pyran i.p. than those given pyran i.v. Chemiluminescence evoked by zymosan was less for PEC from mice given pyran i.v. than for those from untreated mice or those given pyran i.p. Chemiluminescence was greater for adherent splenocytes from mice treated with pyran i.p. than for those from untreated mice or those from mice treated i.v. Pyran administered i.v. is less effective in modulating the host immune response than pyran administered i.p. Immunomodulatory agents such as pyran have adverse as well as beneficial effects depending upon the route of administration.

Animals↗
PubMed1987

Chloroquine resistance of Plasmodium berghei: biochemical basis and countermeasures.

Microsomal monooxygenases, enzymes that metabolize xenobiotics, may be responsible for the chloroquine resistance of malarial parasites. Plasmodium cells contain cytochrome P-450 and exhibit aryl hydrocarbon hydroxylase and aminopyrine N-dimethylase activity, two monooxygenases that inactivate chloroquine. The activities of these monooxygenases are considerably higher in chloroquine-resistant strains of Plasmodium berghei than in the chloroquine-sensitive strain of the parasite. Inhibitors of microsomal monooxygenases have the potential to overcome the chloroquine resistance of Plasmodium spp., and, of those inhibitors tested, the copper-lysine complex, copper(lysine)(2), was the most effective.

Aminopyrine N-Demethylase↗
PubMed1987

[Drug resistance of Plasmodium falciparum malaria in Equatorial Africa. Apropos of cases observed at a military unit stationed in Gabon].

The existence of Plasmodium falciparum chloroquine-resisting clones in equatorial Africa is quite a recent event. Among a French military unit of 138 people who had lived in Gabon from April to August 1986, 24 of them have caught malaria due to Plasmodium falciparum. This allows us to perceive the impact of this event because of the perfect control of chloroquine prophylaxis and the good knowledge of all the attacks of fever which occurred in the field. Admitting 10 of those people into the department of internal medicine of the Military Hospital Desgenettes located in Lyons, we could have seen that trophozoites of Plasmodium falciparum were still persisting 2 months after their return for 8 of them in spite of carrying on chemoprophylaxis. Observing that in the field, sets the problem of the chemoprophylaxis of malaria for the troops maneuvering in chloroquine-resisting areas and warrants, if justified, a work protocol aimed at solving it.

Adult↗
PubMed1985

Infection of Aotus azarae boliviensis monkeys with different strains of Plasmodium vivax.

Sixty-seven splenectomized Aotus azarae boliviensis were infected with strains of Plasmodium vivax from Southeast Asia (2), New Guinea (2), North Korea (1), and Central America (3). Maximum parasitemias varied among the different strains, with the mean maximum parasitemia for the primary infection period being 16,200 per mm3. Animals previously infected with Plasmodium falciparum and Plasmodium malariae produced maximum parasitemias of 30,200 and 11,900 per mm3, respectively. Gametocytes infective to Anopheles freeborni mosquitoes were produced with 7 of the 8 strains examined.

Animals↗
PubMedDate not supplied

[Higher microsomal monooxygenase activity in chloroquine-resistant strains of malarial plasmodium as a possible cause of drug stability].

Ability to hydroxylate benz(alpha)pyrene--a substrate of arylhydrocarbone hydroxylase (AHH) was distinctly increased in lysates of erythrocytes containing malarial plasmodium. Hydroxylation of benz(alpha)pyrene was inhibited by methyrapone--an inhibitor of microsomal monooxygenases. Activity of AHH was increased from 2- to 3-fold in chloroquine-resistant plasmodium strains as compared with the drug-sensitive strains. Resistance of Plasmodium berghei to chloroquine appears to involve an activation of the monooxygenases system in the parasite.

Animals↗
PubMed1981

Blood parasites of birds in Central Europe. 3. Plasmodium and Haemoproteus.

The present paper is the third in the series on blood parasites of birds in Central Europe. It is devoted to the genera Plasmodium and Haemoproteus. Plasmodium has been found in 11.3% of birds belonging to 54 species, most abundant being in Galliformes and Columbiformes. On the other hand, this parasite seems to be absent in Anseriformes, Falconiformes, Hirundinidae and Sturnidae in Central Europe. Haemoproteus has been encountered in the studied region in 11.8% of birds belonging to 85 species. It is most abundant in Falconiformes, Strigiformes, Hirundinidae, Emberizidae, Fringillidae, Muscicapidae, Paridae and Turdidae, but it has not been encountered in Anseriformes. The paper also discusses the dependence of the incidence of these parasites on migratory ability of their hosts and on the nest ecology of birds. Moreover, an ecological outline is given of the representatives of the genera Plasmodium and Haemoproteus in birds in Central Europe, mainly on the basis of the ecological model of avian malaria after Beaudoin et al. (1971).

Animals↗