Oxidative stress and antioxidative status of plasma and erythrocytes in patients with vivax malaria

Albumin levels in malaria patients: a systematic review and meta-analysis of their association with disease severity

Albumin, a key protein in human blood plasma, has been linked to various health conditions. However, its association with malaria, particularly in assessing disease severity, remains inadequately understood. This comprehensive systematic review and meta-analysis aimed to elucidate the relationship between albumin levels and malaria severity. A comprehensive literature search was conducted across multiple databases, including Embase, Scopus, PubMed, MEDLINE, Ovid, and Google Scholar, to identify studies examining albumin levels in malaria patients. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed. Data were pooled using a random-effects model, and heterogeneity was assessed using I2 statistics. Subgroup and meta-regression analyses were performed based on publication year, study location, and Plasmodium species. A total of 37 studies were included in this review. The thematic synthesis indicated that albumin levels in malaria patients varied significantly based on geographical location. A meta-analysis of 28 studies found that albumin levels were significantly lower in malaria patients compared with non-malarial controls (P < 0.001, standardized mean differences [SMD] = -2.23, 95% CI - 3.25 to - 1.20, I2: 98%, random effects model, 28 studies). Additionally, subgroup analysis revealed variations in albumin levels based on geographical location and Plasmodium species. Regarding the association with disease severity, thematic synthesis showed that severe malaria cases generally had decreased albumin levels across various regions. However, one Brazilian study reported higher albumin levels in severe cases. A separate meta-analysis of five studies found significantly lower albumin levels in patients experiencing severe malaria relative to those with less severe forms of the disease (P < 0.001, SMD = -0.66, 95% CI - 1.07 to - 0.25), I2: 73%, random effects model, 5 studies). This study underscores the clinical significance of albumin as a potential biomarker for Plasmodium infection and the severity of malaria. The findings suggest that albumin level monitoring could be crucial in managing malaria patients, especially in assessing disease severity and tailoring treatment approaches. Additional studies are required to investigate the underlying mechanisms driving these associations and validate the clinical utility of albumin levels in malaria patient management.

Malaria Is Associated with Diminished Levels of Ascorbic Acid: A Systematic Review and Meta-Analysis

Background: It is still unclear how ascorbic acid levels relate to the pathogenesis of malaria. This systematic review synthesized different ascorbic acid levels in malaria patients with different severity levels of malaria and Plasmodium species. Methods: The systematic review protocol was registered in the PROSPERO database (CRD42023394849). A systematic search of PubMed, Embase, MEDLINE, Ovid, Scopus, and Google Scholar was conducted to identify studies that reported ascorbic acid and malaria. The pooled standardized mean difference (Cohen's d) with 95% confidence intervals (CIs) was calculated using the random-effects model. Results: A total of 1480 articles were obtained from the searches of the databases, and 30 studies were included for syntheses. The meta-analysis revealed that patients with malaria had lower levels of ascorbic acid than those without malaria or uninfected controls (p < 0.01, Cohen's d = -3.71, 95% CI = -4.44 to -2.98, I2 = 98.87%, 30 studies). Comparable levels of ascorbic acid were observed between patients with severe malaria and those with nonsevere malaria (p = 0.06, Cohen's d = -1.39, 95% CI = -2.85 to 0.07, I2 = 96.58%, 4 studies). Similarly, levels of ascorbic acid were comparable between patients with Plasmodium falciparum and Plasmodium vivax malaria (p = 0.34, Cohen's d = -1.06, 95% CI = -3.23 to 1.12, I2 = 97.30%, 3 studies). Conclusions: The meta-analysis reveals diminished levels of ascorbic acid in malaria cases. Manipulating the host's nutritional status, such as by supplementing it with ascorbic acid to restore reactive oxygen species balance, may alter the progression of malarial infection and prevention of disease severity. Antioxid. Redox Signal. 40, 460-469.

Methemoglobin levels in malaria: a systematic review and meta-analysis of its association with Plasmodium falciparum and Plasmodium vivax infections and disease severity

Reports indicate that Plasmodium infections influence methemoglobin levels. However, findings have been inconclusive or have varied across different geographic and demographic contexts. This systematic review and meta-analysis aimed to consolidate existing data regarding the association between Plasmodium infections and alterations in methemoglobin levels related to the severity of the infection. A comprehensive literature search of several databases, including Ovid, ProQuest, Embase, Scopus, MEDLINE, and PubMed, was conducted to identify relevant studies that examined methemoglobin levels in patients with malaria. Qualitative synthesis and meta-analysis of the pooled standardized mean difference were conducted to synthesize the differences in methemoglobin levels between: (1) patients with malaria and those without malaria and (2) patients with severe malaria and those with uncomplicated malaria based on various themes including publication year, study design, study area, Plasmodium species, age group, symptomatic status, severity status, and method of malaria detection. Of the 1846 studies that were initially identified from the main databases and additional searches on Google Scholar, 10 studies met the eligibility criteria and were selected for this review. The systematic review distinctly highlighted an association between malaria and elevated methemoglobin levels, an observation consistent across diverse geographical regions and various Plasmodium species. Furthermore, the meta-analysis confirmed this by demonstrating increased methemoglobin levels in patients with malaria compared to those without malaria (P < 0.001, Hedges' g 2.32, 95% CI 1.36-3.29, I2 97.27, 8 studies). Moreover, the meta-analysis found elevated methemoglobin levels in patients with severe malaria compared to those with uncomplicated malaria (P < 0.001, Hedges' g 2.20, 95% CI 0.82-3.58, I2 96.20, 5 studies). This systematic review and meta-analysis revealed increased methemoglobin levels in patients with P. falciparum and P. vivax infections, with a notable association between elevated methemoglobin levels and severe malaria. Future research should focus on elucidating the specific mechanisms by which changes in methemoglobin levels are related to infections by P. falciparum and P. vivax, particularly in terms of severity, and how these alterations could potentially impact patient management and treatment outcomes.

Association of reduced glutathione levels with Plasmodium falciparum and Plasmodium vivax malaria: a systematic review and meta-analysis

Reduced glutathione (GSH) is a crucial antioxidant with recognized roles in malaria pathogenesis and host response. Despite its importance, reports on the association of GSH with malaria are inconsistent. Therefore, this systematic review and meta-analysis investigated the differences in GSH levels in relation to Plasmodium infection. A comprehensive literature search of six electronic databases (Embase, MEDLINE, Ovid, PubMed, Scopus, and ProQuest) was conducted. Of the 2158 initially identified records, 18 met the eligibility criteria. The majority of studies reported a significant decrease in GSH levels in malaria patients compared with uninfected controls, and this was confirmed by meta-analysis (P < 0.01, Hedges g: - 1.47, 95% confidence interval [CI] - 2.48 to - 0.46, I2: 99.12%, 17 studies). Additionally, there was no significant difference in GSH levels between Plasmodium falciparum malaria and P. vivax malaria (P = 0.80, Hedges g:  0.11, 95% CI - 0.76 to 0.98, I2: 93.23%, three studies). Similarly, no significant variation was observed between symptomatic and asymptomatic malaria cases (P = 0.78, Hedges g: 0.06, 95% CI - 0.34 to 0.46, I2: 48.07%, two studies). In conclusion, although GSH levels appear to be generally lower in malaria patients, further detailed studies are necessary to fully elucidate this complex relationship.

Association of uric acid levels with severity of Plasmodium infections: a systematic review and meta-analysis

Elevated uric acid (UA) levels have been reported in malaria patients and are particularly prominent in severe malaria cases. This study aims to synthesize the difference in UA levels between malaria patients and uninfected controls, and between patients with severe and non-severe malaria. A comprehensive literature search was carried out across databases such as Embase, MEDLINE, Ovid, PubMed, Scopus, ProQuest, and Google Scholar to identify relevant studies for inclusion. The methodological quality of the included studies was evaluated independently by two reviewers using the JBI critical appraisal tool for observational studies. A meta-analysis was performed to calculate the pooled effect sizes, expressed as Hedges' g, with 95% confidence intervals (CIs). The Hedges' g was pooled using the random-effects model. An initial search yielding a total of 1122 articles, and a final total of 19 studies being included in the review. Elevated UA levels were observed more prominently in malaria patients, especially those with severe manifestations, when compared to uninfected controls. The conducted meta-analysis demonstrated a significant elevation in UA levels in patients suffering from malaria as compared to uninfected controls (P < 0.01, Hedges's g = 1.40, 95% CI 0.84-1.95, I2 = 95.81, 16 studies). The conducted meta-analysis demonstrated a significant elevation in UA levels in patients suffering from severe malaria as compared to non-severe malaria (P < 0.01, Hedges's g = 3.45, 95% CI 1.06-5.83, I2 = 98.73, 6 studies). In summary, these findings provide valuable insights into the potential use of UA as a biomarker for malaria infection and determination of its severity. Further research is needed to validate these findings and to explore the underlying mechanisms that contribute to the elevation of UA levels during malaria infection.

Differences in catalase levels between malaria-infected individuals and uninfected controls: a systematic review and meta-analysis

Inconsistent catalase (CAT) research necessitates a comprehensive review of CAT levels among patients with malaria to achieve better therapeutic strategies. This study aimed to systematically review and meta-analyze available literature on CAT levels in nonpregnant and pregnant individuals with malaria compared with those in uninfected controls, with the goal of providing a robust evidence base for future research and potential interventions. Following PRISMA guidelines, a systematic literature search across six databases was conducted to examine CAT levels in patients with malaria. Data was extracted independently by two reviewers, and study quality was assessed using the Joanna Briggs Institute (JBI) critical appraisal checklist. The standardized mean difference of CAT levels was calculated with heterogeneity assessment. Subgroup and sensitivity analyses were conducted to explore heterogeneity and assess the robustness of the findings. Publication bias was visually and statistically assessed and corrected, if necessary. Statistical analyses were performed using Stata software, with a significance level set at P < 0.05. Nineteen studies were included in the review. These studies, published from before 2000 to 2023, primarily from Africa and Asia, focused on different Plasmodium species and age groups. Results of qualitative synthesis among nonpregnant individuals consistently showed lower CAT levels in malaria-infected individuals, although some studies reported higher levels. No significant differences in CAT levels were found between malaria-infected and uninfected individuals, as demonstrated by a meta-analysis overall (P = 0.05, Hedges' g: - 0.78, 95% confidence interval (CI): (- 1.56)-0.01, I2: 98.47, 15 studies), but subgroup analyses showed significant differences in CAT levels in studies conducted in Africa (P = 0.02, Hedges' g: - 0.57, 95% CI: - 1.02-(0.11), I2: 91.81, 7 studies), and in studies that specifically focused on children (P = 0.03, Hedges' g: - 0.57, 95% CI: - 1.07-(- 0.07), I2: 87.52, 4 studies). Pregnant women showed variations in CAT levels across trimesters. This study provides valuable insights into the association between malaria infection and CAT enzyme levels, particularly in nonpregnant individuals. Furthermore, well-designed studies are essential to decoding the intricacies of this relationship, which could have significant implications for understanding disease processes and improving patient care.

Increased Blood Concentrations of Malondialdehyde in Plasmodium Infection: A Systematic Review and Meta-Analysis

Several studies have evaluated the relationship between malondialdehyde (MDA) concentrations and Plasmodium infections; however, the findings remain inconclusive. This study synthesized differences in MDA concentrations among patients with different levels of clinical severity, uninfected controls, and different Plasmodium species. The research protocol was registered in PROSPERO (CRD42023393540). Systematic literature searches for relevant studies were performed using the Embase, MEDLINE, Ovid, ProQuest, PubMed, Scopus, and Google Scholar databases. Qualitative and quantitative syntheses (meta-analyses) of distinct MDA concentrations between the disease groups were performed. Twenty-three studies met the eligibility criteria and were included in the systematic review. Overall, MDA concentrations were significantly elevated in participants with malaria relative to uninfected controls (p < 0.01, Cohen d: 2.51, 95% confidence interval (CI): 1.88-3.14, I2: 96.22%, 14 studies). Increased MDA concentrations in participants with malaria compared with uninfected controls were found in studies that enrolled patients with P. falciparum malaria (p < 0.01, Cohen d: 2.50, 95% CI: 1.90-3.10, I2: 89.7%, 7 studies) and P. vivax malaria (p < 0.01, Cohen d: 3.70, 95% CI: 2.48-4.92, I2: 90.11%, 3 studies). Our findings confirm that MDA concentrations increase during Plasmodium infection, indicating a rise in oxidative stress and lipid peroxidation. Thus, MDA levels can be a valuable biomarker for evaluating these processes in individuals with malaria. However, further research is necessary to fully elucidate the intricate relationship between malaria, antioxidants, oxidative stress, and the specific role of MDA in the progression of malaria.

Pathogenesis of Anemia in Canine Babesiosis: Possible Contribution of Pro-Inflammatory Cytokines and Chemokines-A Review

Canine babesiosis is a tick-borne protozoan disease caused by intraerythrocytic parasites of the genus Babesia. The infection may lead to anemia in infected dogs. However, anemia is not directly caused by the pathogen. The parasite's developmental stages only have a marginal role in contributing to a decreased red blood cell (RBC) count. The main cause of anemia in affected dogs is the immune response to the infection. This response includes antibody production, erythrophagocytosis, oxidative damage of RBCs, complement activation, and antibody-dependent cellular cytotoxicity. Moreover, both infected and uninfected erythrocytes are retained in the spleen and sequestered in micro-vessels. All these actions are driven by pro-inflammatory cytokines and chemokines, especially IFN-γ, TNF-α, IL-6, and IL-8. Additionally, imbalance between the actions of pro- and anti-inflammatory cytokines plays a role in patho-mechanisms leading to anemia in canine babesiosis. This article is a review of the studies on the pathogenesis of anemia in canine babesiosis and related diseases, such as bovine or murine babesiosis and human or murine malaria, and the role of pro-inflammatory cytokines and chemokines in the mechanisms leading to anemia in infected dogs.

Natural Antioxidants as Additional Weapons in the Fight against Malarial Parasite

BACKGROUND

All currently available antimalarial drugs are developed from natural product lineages that may be traced back to herbal medicines, including quinine, lapachol, and artemisinin. Natural products that primarily target free radicals or reactive oxygen species, play an important role in treating malaria.

OBJECTIVES

This review analyses the role of antioxidative therapy in treating malaria by scavenging or countering free radicals and reviews the importance of natural plant extracts as antioxidants in oxidative therapy of malaria treatment.

METHODS

The search for natural antioxidants was conducted using the following databases: ResearchGate, ScienceDirect, Google Scholar, and Bentham Science with the keywords malaria, reactive oxygen species, natural antioxidants, and antiplasmodial.

CONCLUSION

This study reviewed various literature sources related to natural products employed in antimalarial therapy directly or indirectly by countering/scavenging reactive oxygen species published between 2016 till date. The literature survey made it possible to summarize the natural products used in treating malaria, emphasizing botanical extracts as a single component and in association with other botanical extracts. Natural antioxidants like polyphenols, flavonoids, and alkaloids, have a broad range of biological effects against malaria. This review is pivoted around natural antioxidants obtained from food and medicinal plants and explores their application in restraining reactive oxygen species (ROS). We anticipate this article will provide information for future research on the role of antioxidant therapy in malaria infection.

Oxidative Stress and Pathogenesis in Malaria

Malaria is a highly inflammatory and oxidative disease. The production of reactive oxygen species by host phagocytes is an essential component of the host response to Plasmodium infection. Moreover, host oxidative enzymes, such as xanthine oxidase, are upregulated in malaria patients. Although increased production of reactive oxygen species contributes to the clearance of the parasite, excessive amounts of these free radicals can mediate inflammation and cause extensive damage to host cells and tissues, probably contributing to severe pathologies. Plasmodium has a variety of antioxidant enzymes that allow it to survive amidst this oxidative onslaught. However, parasitic degradation of hemoglobin within the infected red blood cell generates free heme, which is released at the end of the replication cycle, further aggravating the oxidative burden on the host and possibly contributing to the severity of life-threatening malarial complications. Additionally, the highly inflammatory response to malaria contributes to exacerbate the oxidative response. In this review, we discuss host and parasite-derived sources of oxidative stress that may promote severe disease in P. falciparum infection. Therapeutics that restore and maintain oxidative balance in malaria patients may be useful in preventing lethal complications of this disease.

Enhanced apoptotic index, chemokines and inflammatory recruitment in renal tissues shows relationship with the clinical signs in Leishmania-infected dogs

Apoptosis is associated with resolution of inflammation. However, apoptosis may also occur in active inflammation, balancing inflammatory recruitment instead of a resolution event. To test that hypothesis, we measured apoptosis and chemokines expression, involved in recruitment of inflammatory cells. Clinical affected and subclinically infected dogs with canine leishmaniosis (CanL) and uninfected controls were assessed. Apoptosis in renal tissue (glomeruli, tubules, and inflammatory infiltrate) and cellularity in inflammatory foci were quantified. Messenger RNA of CCL5, CCL4, MCP-1, MCP-2, Caspase (Casp) 3, Casp 8, Casp 9, Bax, Bcl₂ and Fas were quantified by qRT PCR. Clinical affected dogs showed more intense inflammation and higher cellularity in the inflammatory infiltrates than subclinically infected ones, which were higher than controls. Glomerular and tubular cells showed higher apoptotic index in clinical affected dogs when compared to controls. Apoptosis within the inflammatory infiltrates was higher in clinical affected dogs. Bax/Bcl₂ ratio and CCL4 showed higher expression in kidney from clinical affected when compared to subclinically infected dogs. Casp 3/CCL4 ratio expression were higher in subclinically infected dogs than in the clinical affected group. Additionally, results suggest that Casp 3/CCL4 ratio is balancing towards an inflammatory recruitment and CCL4 and Bax/Bcl₂ ratio expression is associated with active inflammation in clinical affected CanL. Data demonstrate that apoptosis was not always correlated with resolution of inflammation, when a morphometric and a molecular evaluation were performed concomitantly. In kidneys of Leishmania infected dogs, apoptosis and chemokines may be balancing inflammatory recruitment. In conclusion, Bax/Bcl₂ ratio, chemokines, Casp 8, Casp 3 and Fas were associated with renal apoptosis, active inflammation and increased inflammatory recruitment observed in clinical affected animals, influencing the clinical presentation of leishmaniosis.

Parasite-Host Interaction and Pathophysiology Studies of the Human Relapsing Malarias Plasmodium vivax and Plasmodium ovale Infections in Non-Human Primates

Malaria remains a serious health concern across the globe. Historically neglected, non-Falciparum human malarias were put back on the agenda by a paradigm shift in the fight against malaria from malaria control to malaria eradication. Here, we review the modeling of the relapsing parasites Plasmodium vivax (P. vivax) and Plasmodium ovale (P. ovale) in non-human primates with a specific focus on the contribution of these models to our current understanding of the factors that govern parasite-host interactions in P. vivax and P. ovale parasite biology and pathophysiology.

Biomarkers of disease severity in vivax malaria

Severe complications have been observed and established for Plasmodium falciparum as well as P. vivax infections worldwide. Although P. vivax infection is not fully acknowledged as malignant malaria, recently life-threatening complications have been reported to occur in many studies. The recognition of biomarkers with excellent sensitivity and reliability plays a prime role in disease management. Acute inflammatory response and oxidative stress are observed in malaria due to the production of reactive oxygen species. Lipid and protein oxidative injuries are prospective biomarkers for disease severity owing to the damage caused by the parasite. We have tried to find out whether protein carbonylation (PC), lipid peroxidation (LPO) and superoxide dismutase (SOD) could suffice as a biomarker for severe vivax malaria or not. Blood samples were collected from the individuals attending Jawaharlal Nehru Medical College of Aligarh Muslim University during the wet season of malaria transmission. Microscopy and rapid diagnostic kits were used as a tool for malaria diagnosis. A total of 214 subjects were enrolled for the study: 30 febrile controls and 184 subjects with vivax malaria. Protein carbonylation and lipid peroxidation were found to be directly associated with parasite count and total antioxidant status (TAS). Increase in oxidative stress was also observed in severe vivax malaria patients. Levels of uric acid and bilirubin too were raised in complicated cases. Protein carbonylation was found to be a more reliable indicator of vivax malaria severity than lipid peroxidation.

Evaluation of oxidative stress in caprine anaplasmosis and effect of vitamin E-selenium in monitoring oxidative stress

Caprine anaplasmosis is an economically important tick-borne rickettsial disease that affects goats all over the world. Microscopic examination of stained blood smears from 162 animals revealed inclusion bodies of Anaplasma spp. in 24 cases. Genus specific PCR for Anaplasma spp. yielded positive results in 22 cases. All the diseased animals showed a significant fall in the mean values of antioxidants such as reduced glutathione, superoxide dismutase and catalase and a significant increase in the level of lipid peroxidation. Out of the 22 animals positive for anaplasmosis both in blood smear and PCR, 16 female non pregnant goats selected for study were divided into two groups consisting of eight animals each. Animals belonging to groups I and II were treated with oxytetracycline dihydrate. In addition, animals of group II were supplemented with vitamin E-selenium combination. Oxidative stress parameters were rechecked on the 10th day of treatment. At the end of the study period, a significant reduction in malondialdehyde level and a significant increase in mean value of superoxide dismutase were detected in group II. While there was a significant reduction in lipid peroxidation and a significant increase in superoxide dismutase and catalase values within both the groups after treatment, reduced glutathione showed no significant difference within the group.

Epidemiology, drug resistance, and pathophysiology of Plasmodium vivax malaria

Malaria, caused by the protozoan parasites of the genus Plasmodium, is a major health problem in many countries of the world. Five parasite species namely, Plasmodium falciparum, P. vivax, P. malariae, P. ovale, and P. knowlesi, cause malaria in humans. Of these, P. falciparum and P. vivax are the most prevalent and account for the majority of the global malaria cases. In most areas of Africa, P. vivax infection is essentially absent because of the inherited lack of Duffy antigen receptor for chemokines on the surface of red blood cells that is involved in the parasite invasion of erythrocytes. Therefore, in Africa, most malaria infections are by P. falciparum and the highest burden of P. vivax infection is in Southeast Asia and South America. Plasmodium falciparum is the most virulent and as such, it is responsible for the majority of malarial mortality, particularly in Africa. Although, P. vivax infection has long been considered to be benign, recent studies have reported life-threatening consequences, including acute respiratory distress syndrome, cerebral malaria, multi-organ failure, dyserythropoiesis and anaemia. Despite exhibiting low parasite biomass in infected people due to parasite's specificity to infect only reticulocytes, P. vivax infection triggers higher inflammatory responses and exacerbated clinical symptoms than P. falciparum, such as fever and chills. Another characteristic feature of P. vivax infection, compared to P. falciparum infection, is persistence of the parasite as dormant liver-stage hypnozoites, causing recurrent episodes of malaria. This review article summarizes the published information on P. vivax epidemiology, drug resistance and pathophysiology.

Anti-band 3 and anti-spectrin antibodies are increased in Plasmodium vivax infection and are associated with anemia

Clearance of non-infected red blood cells (nRBCs) is one of the main components of anemia associated with Plasmodium vivax malaria. Recently, we have shown that anemic patients with P. vivax infection had elevated levels of anti-RBCs antibodies, which could enhance in vitro phagocytosis of nRBCs and decrease their deformability. Using immunoproteomics, here we characterized erythrocytic antigens that are differentially recognized by autoantibodies from anemic and non-anemic patients with acute vivax malaria. Protein spots exclusively recognized by anemic P. vivax-infected patients were identified by mass spectrometry revealing band 3 and spectrin as the main targets. To confirm this finding, antibody responses against these specific proteins were assessed by ELISA. In addition, an inverse association between hemoglobin and anti-band 3 or anti-spectrin antibodies levels was found. Anemic patients had higher levels of IgG against both band 3 and spectrin than the non-anemic ones. To determine if these autoantibodies were elicited because of molecular mimicry, we used in silico analysis and identified P. vivax proteins that share homology with human RBC proteins such as spectrin, suggesting that infection drives autoimmune responses. These findings suggest that band 3 and spectrin are potential targets of autoantibodies that may be relevant for P. vivax malaria-associated anemia.

Ameliorative Effect of Caffeic Acid on Capecitabine-Induced Hepatic and Renal Dysfunction: Involvement of the Antioxidant Defence System

Background: It has been postulated that during liver and kidney damage there is a decreased in the antioxidant status associated with a simultaneous increase in the reactive oxygen species and lipid peroxidation. In consonant with this, Capecitabine, an oral chemotherapy and inactive non-cytotoxic fluoropyrimidine considered for the treatment of advance colorectal cancer, has also been shown to induce oxidative stress in liver tissues. Caffeic acid, a typical hydroxycinnamic, has been claimed to be effective against oxidative stress. Therefore, this present work studied the protective effect of caffeic acid on oxidative stress-induced liver and kidney damage by the administration of capecitabine. Methods: Twenty-four male Wistar strain rats were randomly divided into four treatment groups: A. control, B. capecitabine (CPTB)-treated group (30 mg/kg b.w. CPTB), C. caffeic acid (CFA)-treated group (100 mg/kg b.w. CFA) and D. co-treated group with CFA (100 mg/kg b.w.) and CPTB (30 mg/kg b.w.). Results: Caffeic acid administration significantly ameliorated the elevated plasma biomarkers of hepatic and renal tissue damage induced by the capecitabine and improved enzymatic and non-enzymatic antioxidant levels in liver organ. Conclusions: The protective effect of caffeic acid could be attributed to its ability to boost the antioxidant defence system and reduce lipid peroxidation.

Relation of antioxidant status at admission and disease severity and outcome in dogs naturally infected with Babesia canis canis

BACKGROUND

Canine babesiosis is caused by species of the Babesia genus and has become an emerging disease worldwide. To the authors' knowledge there are no reports in which antioxidants have been analyzed in different presentations of canine babesiosis or in which the prognostic value of antioxidants has been studied. The aim of this study was to evaluate whether oxidative stress could be related to the severity and outcome of canine babesiosis. For this purpose a profile consisting of four antioxidant biomarkers (superoxide dismutase - SOD, glutathione peroxidase - GPx, catalase, total antioxidant status - TAS) and malondialdehyde - MDA as an oxidant biomarker (previously evaluated, here studied for comparative purposes) were evaluated in dogs with canine babesiosis of different clinical severity and outcomes.

RESULTS

The study was conducted with a sample of 40 dogs suffering from babesiosis (further divided into uncomplicated, one complication and multiple organ dysfunction syndrome - MODS group) and 30 healthy dogs (control group). Additionally, the babesiosis group was divided according to the anaemia into non-anaemic, mildly anaemic, moderately anaemic and severely anaemic dogs. The results of our study showed significantly decreased SOD, catalase and TAS values in diseased dogs compared to controls, while there were no significant differences in GPx between these groups. Dogs that developed MODS showed lower activities of SOD and GPx and higher MDA values compared to dogs with uncomplicated babesiosis as well as with dogs that developed one complication. Superoxide dismutase, catalase and GPx were negatively correlated whereas MDA was positively correlated with the lethal outcome of the disease. Furthermore, this study detected more pronounced decrease in antioxidant biomarkers (SOD, GPx and catalase) in dogs with moderate anaemia compared to those with mild anaemia.

CONCLUSIONS

The results of this study showed changes in biomarkers related to the antioxidant status of dogs naturally infected with B. canis canis. These biomarkers could be used as indicators of disease severity and outcome in dogs suffering from babesiosis.

Anti-erythrocyte antibodies may contribute to anaemia in Plasmodium vivax malaria by decreasing red blood cell deformability and increasing erythrophagocytosis

Background

Plasmodium vivax accounts for the majority of human malaria infections outside Africa and is being increasingly associated in fatal outcomes with anaemia as one of the major complications. One of the causes of malarial anaemia is the augmented removal of circulating non-infected red blood cells (nRBCs), an issue not yet fully understood. High levels of auto-antibodies against RBCs have been associated with severe anaemia and reduced survival of nRBCs in patients with falciparum malaria. Since there are no substantial data about the role of those antibodies in vivax malaria, this study was designed to determine whether or not auto-antibodies against erythrocytes are involved in nRBC clearance. Moreover, the possible immune mechanisms elicited by them that may be associated to induce anaemia in P. vivax infection was investigated.

Methods

Concentrations of total IgG were determined by sandwich ELISA in sera from clinically well-defined groups of P. vivax-infected patients with or without anaemia and in healthy controls never exposed to malaria, whereas the levels of specific IgG to nRBCs were determined by cell-ELISA. Erythrophagocytosis assay was used to investigate the ability of IgGs purified from each studied pooled sera in enhancing nRBC in vitro clearance by THP-1 macrophages. Defocusing microscopy was employed to measure the biomechanical modifications of individual nRBCs opsonized by IgGs purified from each group.

Results

Anaemic patients had higher levels of total and specific anti-RBC antibodies in comparison to the non-anaemic ones. Opsonization with purified IgG from anaemic patients significantly enhanced RBCs in vitro phagocytosis by THP-1 macrophages. Auto-antibodies purified from anaemic patients decreased the nRBC dynamic membrane fluctuations suggesting a possible participation of such antibodies in the perturbation of erythrocyte flexibility and morphology integrity maintenance.

Conclusions

These findings revealed that vivax-infected patients with anaemia have increased levels of IgG auto-antibodies against nRBCs and that their deposition on the surface of non-infected erythrocytes decreases their deformability, which, in turn, may enhance nRBC clearance by phagocytes, contributing to the anaemic outcome. These data provide insights into the immune mechanisms associated with vivax malaria anaemia and may be important to the development of new therapy and vaccine strategies.

Ameliorative Effect of Gallic Acid on Cyclophosphamide-Induced Oxidative Injury and Hepatic Dysfunction in Rats

Cyclophosphamide (CP), a bifunctional alkylating agent used in chemotherapy has been reported to induce organ toxicity mediated by generation of reactive oxygen species and oxidative stress. Gallic acid (GA), a phenolic substance, is a natural antioxidant with proven free radical scavenging activity and offers protection against oxidative damage. This research study was designed to investigate the ameliorative effect of GA against CP-induced toxicity in rats. Twenty-five male Wistar rats (180-200 g) were randomized into five treatment groups: (A) control, (B) CP, 2 mg/kg body weight (b.w.), (C) pre-treatment with GA (20 mg/kg b.w.) for seven days followed by CP (2 mg/kg b.w.) for seven days, (D) co-treatment with GA (20 mg/kg b.w) and CP (2 mg/kg b.w.) for seven days, and (E) GA (20 mg/kg b.w.) for seven days. CP induced marked renal and hepatic damages as plasma levels of urea, creatinine, bilirubin and activities of AST, ALT, ALP and GGT were significantly elevated (p < 0.05) in the CP-treated group relative to control. In addition, hepatic levels of GSH, vitamin C and activities of SOD, catalase and GST significantly reduced in the CP-treated group when compared with control. This was accompanied with a significant increase in hepatic lipid peroxidation. The restoration of the markers of renal and hepatic damages as well as antioxidant indices and lipid peroxidation by pre- and co-treatment with GA clearly shows that GA offers ameliorative effect by scavenging the reactive oxygen species generated by CP. This protective effect may be attributed to the antioxidant property of gllic acid.

Study of Methaemoglobin in Malaria Patients

To estimate the concentration of methemoglobin (MetHb) in malaria patients and correlate with severity of malaria infection. This prospective study included 30 untreated cases of malaria confirmed by Quantitative Buffy Coat (QBC) test and 30 age sex matched non-malarial cases taken as controls. All the patients underwent thorough clinical examination and routine biochemical investigation. Methemoglobin levels were estimated by spectrophotometric (co-oxymeter) method on day 1 and day 10 of diagnosis of all study group patients and correlated with clinical profile and severity. Out of 30 malaria patients 22 were males and eight were females. The clinical presentations in complicated malaria group (n = 21) were fever 21 (100 %), anemia 17 (80.95 %), renal failure 12 (52.38 %) and coma/convulsion 5 (23.8 %). The mean age of the study group was 41.66 years. Mean MetHb in complicated malaria on day 1 was 2.55 ± 1.75 % and day 10 was 10.69 ± 8.19 % (statistically significant). The overall mortality was 13 (43.33 %) among study group while 5 (16.66 %) was found among control group. Mean MetHb who died (n = 13) on day 1 was 3.144 ± 1.829 % and (n = 8) on day 10 it was 19.982 ± 8.406 %. Increase in level of methaemoglobin is detrimental to the body and is associated with increase in mortality. Routine MetHb estimation may be used as a prognostic indicator in the management of malaria patients. It is suggested that addition of drugs which reduce MetHb may be tried along with antimalarial drugs to decrease morbidity and mortality in malaria.

The avian transcriptome response to malaria infection

Malaria parasites are highly virulent pathogens which infect a wide range of vertebrates. Despite their importance, the way different hosts control and suppress malaria infections remains poorly understood. With recent developments in next-generation sequencing techniques, however, it is now possible to quantify the response of the entire transcriptome to infections. We experimentally infected Eurasian siskins (Carduelis spinus) with avian malaria parasites (Plasmodium ashfordi), and used high-throughput RNA-sequencing to measure the avian transcriptome in blood collected before infection (day 0), during peak parasitemia (day 21 postinfection), and when parasitemia was decreasing (day 31). We found considerable differences in the transcriptomes of infected and uninfected individuals, with a large number of genes differentially expressed during both peak and decreasing parasitemia stages. These genes were overrepresented among functions involved in the immune system, stress response, cell death regulation, metabolism, and telomerase activity. Comparative analyses of the differentially expressed genes in our study to those found in other hosts of malaria (human and mouse) revealed a set of genes that are potentially involved in highly conserved evolutionary responses to malaria infection. By using RNA-sequencing we gained a more complete view of the host response, and were able to pinpoint not only well-documented host genes but also unannotated genes with clear significance during infection, such as microRNAs. This study shows how the avian blood transcriptome shifts in response to malaria infection, and we believe that it will facilitate further research into the diversity of molecular mechanisms that hosts utilize to fight malaria infections.

Influence of Different Doses of Levofloxacin on Antioxidant Defense Systems and Markers of Renal and Hepatic Dysfunctions in Rats

Levofloxacin (LFX) is a broad spectrum fluoroquinolone antibiotic used in the treatment of infections such as pneumonia, chronic bronchitis, and sinusitis. The present study assessed the likely toxic effect of LFX on hepatic and renal tissues in rats. Twenty male Wistar rats were randomly divided into four treatment groups: A: control, B: 5 mg/kg bw LFX (half therapeutic dose), C: 10 mg/kg bw LFX (therapeutic dose), and D: 20 mg/kg bw LFX (double therapeutic dose). After seven days of administration, result indicated significant (P<0.05) increase in plasma ALT, AST, and ALP activities in the treated groups compared to control. Also, there was a significant increase in plasma creatinine, urea, and total bilirubin in the treated groups relative to control. Plasma total cholesterol, HDL-cholesterol, LDL-cholesterol, and triglycerides also increased significantly in the treated groups relative to control. Also, hepatic MDA level increased significantly in all the treated groups. However, hepatic SOD, catalase, and GST activities were significantly reduced in the LFX-treated animals. Moreover, GSH and ascorbic acid levels were significantly decreased in the LFX-treated groups relative to control. In conclusion, three doses of levofloxacin depleted antioxidant defense system and induced oxidative stress and hepatic and renal dysfunctions in rats.

Potential immune mechanisms associated with anemia in Plasmodium vivax malaria: a puzzling question

The pathogenesis of malaria is complex, generating a broad spectrum of clinical manifestations. One of the major complications and concerns in malaria is anemia, which is responsible for considerable morbidity in the developing world, especially in children and pregnant women. Despite its enormous health importance, the immunological mechanisms involved in malaria-induced anemia remain incompletely understood. Plasmodium vivax, one of the causative agents of human malaria, is known to induce a strong inflammatory response with a robust production of immune effectors, including cytokines and antibodies. Therefore, it is possible that the extent of the immune response not only may facilitate the parasite killing but also may provoke severe illness, including anemia. In this review, we consider potential immune effectors and their possible involvement in generating this clinical outcome during P. vivax infections.

Lipid peroxidation and antioxidant enzymes activity in Plasmodium vivax malaria patients evolving with cholestatic jaundice

BACKGROUND

Plasmodium vivax infection has been considered a benign and self-limiting disease, however, recent studies highlight the association between vivax malaria and life-threatening manifestations. Increase in reactive oxygen species has already been described in vivax malaria, as a result of the increased metabolic rate triggered by the multiplying parasite, and large quantities of toxic redox-active byproducts generated. The present study aimed to study the oxidative stress responses in patients infected with P. vivax, who developed jaundice (hyperbilirubinaemia) in the course of the disease, a common clinical complication related to this species.

METHODS

An evaluation of the lipid peroxidation and antioxidant enzymes profile was performed in 28 healthy individuals and compared with P. vivax infected patients with jaundice, i.e., bilirubin < 51.3 μmol/L (8 patients) or without jaundice (34 patients), on day 1 (D1) and day 14 (D14) after anti-malarial therapy.

RESULTS

Hyperbilirubinaemia was more frequent among women and patients experiencing their first malarial infection, and lower haemoglobin and higher lactate dehydrogenase levels were observed in this group. Malondialdehyde levels and activity of celuroplasmin and glutathione reductase were increased in the plasma from patients with P. vivax with jaundice compared to the control group on D1. However, the activity of thioredoxin reductase was decreased. The enzymes glutathione reductase, thioredoxin reductase, thiols and malondialdehyde also differed between jaundiced versus non-jaundiced patients. On D14 jaundice and parasitaemia had resolved and oxidative stress biomarkers were very similar to the control group.

CONCLUSION

Cholestatic hyperbilirubinaemia in vivax malaria cannot be totally disassociated from malaria-related haemolysis. However, significant increase of lipid peroxidation markers and changes in antioxidant enzymes in patients with P. vivax-related jaundice was observed. These results suggest oxidative processes contributing to malaria pathogenesis, what may be useful information for future anti-oxidant therapeutical interventions in these patients.

Antioxidant activity in HIV and malaria co-infected subjects in Anambra State, southeastern Nigeria

OBJECTIVE

To determine the antioxidant status of HIV and malaria co-infected participants.

METHODS

Blood samples collected from the 193 randomly recruited participants were used for HIV screening, Plasmodium falciparum antigen screening, malaria parasite density count, CD4(+) T cell count, glutathione reductase, glutathione peroxidase and total antioxidant status measurement. Standard laboratory methods were used for the analysis.

RESULTS

The results showed that glutathione reductase, glutathione peroxidase, total antioxidant status and CD4(+) T cell count were significantly lowered in symptomatic HIV participants with and without malaria co-infection (P<0.01) in each case compared with control participants. Also, glutathione reductase, glutathione peroxidise, total antioxidant status and CD4(+) T cell count were significantly lowered in asymptomatic HIV participants with and without malaria co-infection (P<0.05) in each case, compared with control participants without malaria. Similarly, these antioxidants were significantly lowered in control participants with malaria infection (P<0.05) compared with control participants without malaria. The malaria parasite density in symptomatic HIV infected participants was negatively associated with glutathione reductase (r = -0.906, P<0.01), glutathione peroxidase (r = -0.719, P<0.01) and total antioxidant status (r = -0.824, P<0.01).

CONCLUSIONS

The antioxidant activity was affected in HIV infected participants with malaria co-infection. Malaria co-infection in HIV seems to exert additional burden on antioxidants. This calls for concern in malaria endemic areas with increasing prevalence of HIV infection.

Plasmodium vivax: clinical spectrum, risk factors and pathogenesis

Vivax malaria was historically described as 'benign tertian malaria' because individual clinical episodes were less likely to cause severe illness than Plasmodium falciparum. Despite this, Plasmodium vivax was, and remains, responsible for major morbidity and significant mortality in vivax-endemic areas. Single infections causing febrile illness in otherwise healthy individuals rarely progress to severe disease. Nevertheless, in the presence of co-morbidities, P. vivax can cause severe illness and fatal outcomes. Recurrent or chronic infections in endemic areas can cause severe anaemia and malnutrition, particularly in early childhood. Other severe manifestations include acute lung injury, acute kidney injury and uncommonly, coma. Multiorgan failure and shock are described but further studies are needed to investigate the role of bacterial and other co-infections in these syndromes. In pregnancy, P. vivax infection can cause maternal anaemia, miscarriage, low birth weight and congenital malaria. Compared to P. falciparum, P. vivax has a greater capacity to elicit an inflammatory response, resulting in a lower pyrogenic threshold. Conversely, cytoadherence of P. vivax to endothelial cells is less frequent and parasite sequestration is not thought to be a significant cause of severe illness in vivax malaria. With a predilection for young red cells, P. vivax does not result in the high parasite biomass associated with severe disease in P. falciparum, but a four to fivefold greater removal of uninfected red cells from the circulation relative to P. falciparum is associated with a similar risk of severe anaemia. Mechanisms underlying the pathogenesis of severe vivax syndromes remain incompletely understood.

Oxidative stress in vivax malaria

Malaria is still a leading cause of morbidity and mortality. The increase in lipid peroxidation reported in malaria infection and antioxidant status may be a useful marker of oxidative stress during malaria infection. The aim of this study was to investigate the role of antioxidant enzymes against toxic reactive oxygen species in patients infected with Plasmodium vivax and healthy controls. Malondialdehyde levels, superoxide dismutase, and glutathione peroxidase activities were determined in 91 P. vivax patients and compared with 52 controls. Malondialdehyde levels, superoxide dismutase, and glutathione peroxidase activities were 8.07±2.29 nM/ml, 2.69±0.33 U/ml, and 49.6±3.2 U/g Hb in the patient group and 2.72±0.50 nM/ml, 3.71±0.47 U/ml, and 62.3±4.3 U/g Hb in the control group, respectively. Malondialdehyde levels were found statistically significant in patients with vivax malaria higher than in healthy controls (P<0.001). On the other hand, superoxide dismutase and glutathione peroxidase activities were found to be significantly lower in vivax malaria patients than in controls (P<0.05). There was an increase in oxidative stress in vivax malaria. The results suggested that antioxidant defense mechanisms may play an important role in the pathogenesis of P. vivax.

Comparative study on lipid peroxidation and antioxidant vitamins E and C inFalciparum andVivax malaria

Reactive oxygen species are thought to be involved in the pathogenesis of Malaria. To assess the extent of oxidative stress, a study was conducted in patients withPlasmodium falciparum malaria andPlasmodium Vivax malaria. Plasma Thiobarbituric acid reactive substances (TBARS) were measured to assess the degree of lipid peroxidation. Antioxidant status was measured by estimating the levels of Vitamins E and C. Results were compared with age and sex matched control subjects. This study suggests that plasma TBARS levels were significantly increased in malaria patients. The patients withP. falciparum infection showed significantly increased levels of lipid peroxides when compared toP. vivax malaria. The antioxidant Vitamins E and C were decreased significantly in malaria patients in both the groups. Maximum decline in Vitamin C was observed inP. vivax malaria. Therefore it is been hypothesized that antioxidant Vitamins E and C could provide protection against the oxidative stress induced by malaria.

Studies on biochemical changes with special reference to oxidant and antioxidants in malaria patients

Oxidative stress plays an important role in the development of malarial anemia. The present study was undertaken to study the role of oxidant and antioxidants in the patients ofPlasmodium falciparum malaria (n=25),Plasmodium vivax malaria (n=25) as against the normal control subjects (n=25). The parameters included are the hematological [hemoglobin, erythrocyte adenosine deaminase (ADA) activity, ADP-induced platelet aggregation] and serum total lipid peroxide as an index of oxidative stress and antioxidants [erythrocytic superoxide dismutase (SOD) activity, serum vitamin E] & serum iron.Significant alterations in all above parameters were noted in both groups of malaria patients as compared to control subjects. Maximum significant alterations in hematological parameters were noticed inP. falciparum infection as compared toP. vivax malaria (p<0.001). Substantial rise in serum total lipid peroxides and a significant reduction in antioxidants such as serum vitamin E and serum iron were noted inP. falciparum malaria as compared toP. vivax malaria (p<0.001), whereas maximum decline in erythrocytic SOD activity was observed inP. vivax infection as compared toP. falciparum malaria (p<0.05). Follow-up examination revealed the restoration of the levels of all biochemical parameters to the normal level after 20 days of antimalarial therapy.The study specified severity ofP. falciparum malaria and also functional duality of oxidant.

Serum of Babesia rodhaini infected mice down regulates catalase activity of healthy erythrocytes

Hemolytic activity for animals infected with various Babesia species is well reported. In this study, we confirmed that serum of Babesia rodhaini-infected mice also showed hemolytic activity. Erythrocytes from non-infected mice were lysed by co-incubation with B. rodhaini-infected serum. Catalase activity of the non-infected target erythrocytes was suppressed after this co-incubation with the hemolytic serum of B. rodhaini-infected mice. Furthermore, serum hemolytic activity was inhibited when target erythrocytes were incubated with hemolytic serum in the presence of exogenous catalase. Our study indicated that hemolytic serum can down-regulate the antioxidant capacity of non-infected healthy erythrocytes, possibly as a result of catalase activity, thereby leading to hemolysis.

The anaemia of Plasmodium vivax malaria

Plasmodium vivax threatens nearly half the world's population and is a significant impediment to achievement of the millennium development goals. It is an important, but incompletely understood, cause of anaemia. This review synthesizes current evidence on the epidemiology, pathogenesis, treatment and consequences of vivax-associated anaemia. Young children are at high risk of clinically significant and potentially severe vivax-associated anaemia, particularly in countries where transmission is intense and relapses are frequent. Despite reaching lower densities than Plasmodium falciparum, Plasmodium vivax causes similar absolute reduction in red blood cell mass because it results in proportionately greater removal of uninfected red blood cells. Severe vivax anaemia is associated with substantial indirect mortality and morbidity through impaired resilience to co-morbidities, obstetric complications and requirement for blood transfusion. Anaemia can be averted by early and effective anti-malarial treatment.

Serum proteome analysis of vivax malaria: An insight into the disease pathogenesis and host immune response

Vivax malaria is the most widely distributed human malaria resulting in 80-300 million clinical cases every year. It causes severe infection and mortality but is generally regarded as a benign disease and has not been investigated in detail. The present study aimed to perform human serum proteome analysis in a malaria endemic area in India to identify potential serum biomarkers for vivax malaria and understand host response. The proteomic analysis was performed on 16 age and gender matched subjects (vivax patients and control) in duplicate. Protein extraction protocols were optimized for large coverage of the serum proteome and to obtain high-resolution data. Identification of 67 differentially expressed and statistically significant (Student's t-test; p<0.05) protein spots was established by MALDI-TOF/TOF mass spectrometry. Many of the identified proteins such as apolipoprotein A and E, serum amyloid A and P, haptoglobin, ceruloplasmin, and hemopexin are interesting from a diagnostic point of view and could further be studied as potential serum biomarkers. The differentially expressed serum proteins in vivax malaria identified in this study were subjected to functional pathway analysis using multiple software, including Ingenuity Pathway Analysis (IPA), Protein ANalysis THrough Evolutionary Relationships (PANTHER) and Database for Annotation, Visualization and Integrated Discovery (DAVID) functional annotation tool for better understanding of the biological context of the identified proteins, their involvement in various physiological pathways and association with disease pathogenesis. Functional pathway analysis of the differentially expressed proteins suggested the modulation of multiple vital physiological pathways, including acute phase response signaling, complement and coagulation cascades, hemostasis and vitamin D metabolism pathway due to this parasitic infection. This article is part of a Special Issue entitled: Proteomics: The clinical link.

Thrombocytopenia in childhood malaria with special reference to P. vivax monoinfection: A study from Bikaner (Northwestern India)

Thrombocytopenia is commonly seen in Plasmodium vivax malaria, but its prognostic value has not been addressed in children. This prospective study included 676 admitted children of malaria [Plasmodium falciparum (Pf) monoinfection 262, Plasmodium vivax (Pv) monoinfection 380, and mixed (Pf + Pv) infection 34], in which thrombocytopenia (platelet count <150 × 10(3)/mm(3) on admission) was found in 442 (65.38%) children [Pf monoinfection 55.3% (145/262), Pv monoinfection 73.16% (278/380), and mixed infection 55.88% (19/34)]. The association of thrombocytopenia was statistically significant with Pv monoinfection [73.16% (278/380)] in comparison to either Pf monoinfection [55.34% (145/262); odds ratio (OR) = 2.199 (95% confidence interval (CI) 1.577-3.068), p < 0.0001] or mixed infection [55.88% (19/34); OR = 2.152 (95%CI 1.054-4.394), p = 0.032]. In Pv monoinfection, thrombocytopenia was highest in 0-5 years age group and subsequently decreased with advancing age, whereas in Pf monoinfection it was reverse. Severe thrombocytopenia (platelet count <20 × 10(3)/mm(3)) was present in 16.52% (73/442) children [Pv monoinfection 21.58% (60/278) and Pf monoinfection 8.97% (13/145)]. The risk of developing severe thrombocytopenia was also highest in Pv monoinfection [15.79% (60/380)] in comparison to Pf monoinfection [10.59% (13/262); OR = 3.591 (95%CI 1.928-6.690), p < 0.0001]. Bleeding manifestations were associated in 21.27% (94/442) children [Pf monoinfection 9.92% (26/262), Pv monoinfection 16.58% (63/380), and mixed malaria 14.71% (5/34)]. All the children having bleeding manifestations had thrombocytopenia but low platelet counts were not always associated with abnormal bleeding. The association of severe malaria was significantly more among children having Pv monoinfection with platelet counts <20 × 10(3)/mm(3) [OR = 2.569 (95%CI 1.196-5.517), p < 0.014] with specificity of 88.3% and positive predictive value of 85%. Till today, thrombocytopenia is not included in severe malaria criterion described by WHO, but when platelet counts <20 × 103/mm(3), we advocate it to include as one of the severe malaria criteria.

Evaluation of oxidant and antioxidant status in infants with hyperbilirubinemia and kernicterus

Objective: The objective of the present study was to determine oxidant and antioxidant status in infants with hyperbilirubinemia and/or kernicterus and to find whether there is a relationship between bilirubin level and oxidant/antioxidant status. Patients: The study includes 69 full-term newborns (neonates with hyperbilirubinemia needing phototherapy [Group 1, n = 36] and neonates with kernicterus [Group 2, n = 33]) and 25 age-matched healthy newborn. Results: Plasma total antioxidant capacity (TAC) and serum total oxidant status (TOS) were significantly higher in Groups 1 and 2 than the control group. There was a significant difference between Group 1 and control cases for malondialdehyde (MDA; p < 0.001). Total free sulfhydryl group (TTHI) values were significantly elevated in Group 1 compared to Group 2 and control cases. Correlation analysis showed that the correlation between total bilirubin (TB) and TAC, TOS, MDA and oxidative stress index may be expressed by a quadratic curve. After phototherapy, a statistically significant increase in nitrite level was observed. Conclusion: We demonstrated that the relationship between serum TB and antioxidants and oxidative stress could be expressed by a quadratic correlation curve.

Thrombocytopenia in Plasmodium falciparum, Plasmodium vivax and mixed infection malaria: a study from Bikaner (Northwestern India)

The occurrence, relation and magnitude of thrombocytopenia in different species of malaria are not clearly defined. This study included 1,064 patients admitted with malaria to study thrombocytopenia (platelet count <150,000 /cumm) in Plasmodium falciparum (Pf) and Plasmodium vivax (Pv) mono infection and mixed infection (Pf + Pv). The species diagnosis was done by peripheral blood film (PBF) and rapid diagnostic test (RDT). Validation by polymerase chain reaction (PCR) was done only in patients with severe thrombocytopenia (platelet count <20,000 /cumm). The breakup of patients was 525 (49.34%) Pf, 460 (43.23%) Pv and 79 (7.42%) mixed malaria (Pf + Pv). Thrombocytopenia was observed in 24.6% (262/1064) patients. The risk was greatest in the mixed infections in comparison to monoinfection individually (43.04% [34/79]; mixed vs Pv monoinfection: Odds Ratio [OR] = 1.675 [95% Confidence Interval (CI) 1.029-2.726], p < 0.0366; mixed vs Pf monoinfection: OR=3.911 [95% CI 2.367-6.463], p < 0.0001). Pv monoinfection (31.09% [143/460]) had greater risk compared to Pf monoinfection (16.19% [85/525]; OR = 2.335 [95% CI 1.722-3.167], p < 0.0001). The occurrence of severe thrombocytopenia was also higher in Pv monoinfection (18.18% [26/143]) in comparison to either Pf monoinfection (10.59% [9/85], OR = 1.877 (95% CI 0.834-4.223)) or mixed infection (11.76% [4/34]; OR = 1.667 (95% CI 0.540-5.142) but this association was statistically not significant. Six patients (3 Pv, 2 Pf and 1 mixed) developed severe epistaxis requiring platelet transfusion. There was no relation between parasite density and platelet count as many patients with severe thrombocytopenia had parasite density similar to patients without thrombocytopenia. We found that the association of thrombocytopenia was statistically more significant with P. vivax monoinfection as compared to P. falciparum.

The association of oxidant status and antioxidant capacity in children with acute and chronic ITP

PURPOSE

This study was undertaken to investigate oxidant and antioxidant systems in patients with immune thrombocytopenic purpura (ITP). With this purpose, we measured the levels of serum malondialdehyde (MDA), total antioxidant capacity (TAC), total oxidant status (TOS), and other oxidative stress parameters.

PATIENTS AND METHODS

Fifty-two pediatric patients with ITP (25 acute, 27 chronic) and 21 healthy children were included in the study. Patients with acute ITP were studied, before and after, methylprednisolone treatment.

RESULTS

Hemoglobin, hematocrit, platelet count, and TAC were statistically significantly lower in patients with acute ITP before treatment than those in the control group (P<0.05). In addition, in this group, MDA, TOS levels, and OSI (oxidative stress index) were found to be higher than those in the control group. In chronic ITP group, although hemoglobin hematocrit, platelet counts, and TAC levels were statistically significantly lower than those in the control groups,the mean platelet volume, MDA, TOS, and OSI were found to be statistically significantly higher (P<0.05). Platelet count and mean platelet volume values were statistically significantly lower in patients with acute ITP before treatment than after treatment (P<0.05). We also found a positive correlation between thrombocyte count and TAC, in patients with acute ITP before treatment (r: 0.601, P<0.001) and acute ITP after treatment (r: 0.601, P<0.001) and chronic ITP (r: 0.601, P<0.001). A negative correlation was found between thrombocyte count and serum MDA levels, in patients with acute ITP before treatment (r: -0.356, P<0.001) and acute ITP after treatment (r: -0.356, P<0.001) and chronic ITP (r: -0.356, P<0.001). We also found a negative correlation between thrombocyte count and serum OSI, in patients with acute ITP before treatment (r: -0.494, P<0.001) and acute ITP after treatment (r: -0.494, P<0.001) and chronic ITP (r: -0.494, P<0.001). A negative correlation was found between thrombocyte count and TOS, in patients with acute ITP before treatment (r: -0.470, P<0.001) and acute ITP after treatment (r: -0.470, P<0.001) and chronic ITP (r: -0.470, P<0.001). In conclusion, increased MDA, TOS and OSI, and decreased TAC levels were found in patients with acute and chronic ITP.

CONCLUSIONS

On the basis of these findings, we suggest that free oxygen radicals may have an effect on the structural and functional damage of platelets, and on the mechanism of thrombocytopenia in both, acute and chronic ITP.

Clinical and biochemical studies on Theileria annulata in Egyptian buffaloes (Bubalus bubalis) with particular orientation to oxidative stress and ketosis relationship

This study was carried out on 68 Theileria annulata naturally infected buffaloes in addition to 25 parasitologically free buffaloes distributed in small herds at Dakahlia and Gharbya governorates, Egypt, to demonstrate the clinical picture associated with theileriosis in this buffaloes with particular emphasis to the oxidative stress and ketosis relationship. Clinical signs recorded in infected buffaloes were in the form of fever, enlargement of one or more lymph node, ocular discharge, corneal opacity, skin lesions, decreased milk yield, pale mucous membrane and anorexia. Blood and serum analysis revealed significant (p<or=0.05) decrease in RBCS and or Hb concentration in infected animals compared to control ones. Moreover, significant increase (p<or=0.05) in the levels of beta hydroxy butyric acid (BHBA) and non-esterified free fatty acid (NEFA) with a significant decrease (p<or=0.05) in the levels of reduced glutathione (R.GSH), superoxide dismutase (SOD), catalase (CAT), total antioxidant capacity (TAC), nitric oxide (NO), glucose and glucose-6-phosphate dehydrogenase (G6PD) in infected animals compared to control ones. It can be concluded that T. annulata plays an important role in the occurrence of anemia, oxidative and ketotic stressor in Egyptian water buffaloes.

Retinol supplementation in murine Plasmodium berghei malaria: Effects on tissue levels, parasitaemia and lipid peroxidation

Reduced plasma retinol concentrations occur in human malaria but the benefits of supplementation remain uncertain. We assessed the in vivo efficacy of retinol administration, and its effect on lipid peroxidation, in a Plasmodium berghei murine model. Animals received vehicle (n=17) or retinol (i) before P. berghei inoculation (four doses), (ii) at parasitaemia 10-15% (three to four doses) or (iii) before and after inoculation (six to seven doses; n=15 in each group), with euthanasia on day 8 post-inoculation or when the parasitaemia exceeded 50%. Multiple-dose pre-inoculation retinol reduced endpoint parasitaemia by 24% (P=0.001 versus controls). A reduction of 18% (P=0.042) was observed when retinol was given to parasitaemic animals. Retinol was ineffective when given both before and after infection (11% reduction; P=0.47). Although retinol supplementation did not change plasma retinol concentrations, liver retinol content increased and correlated inversely with endpoint parasitaemia (r=-0.45, P=0.001). Malaria infection augmented concentrations of the free radical lipid peroxidation end-product F(2)-isoprostanes in plasma, erythrocytes and liver by 1.8-, 2.8- and 4.9-fold, respectively, but retinol supplementation had no effect on these increases. Consistent with some human malaria studies, prophylactic retinol reduces P. berghei parasitaemia. This effect relates to augmentation of tissue retinol stores rather than to retinol-associated changes in oxidant status.

Decreased glutathione-S-transferase activity: Diagnostic and protective role in vivax malaria

OBJECTIVES

The study was undertaken to establish data on the comparative status of antioxidant enzyme GST activity, levels of lipid peroxidation and catalase activity during pathology of Plasmodium vivax malaria in Indian population. We investigated whether serum and plasma glutathione-S-transferase activity in vivax patients are unique to the disease or act as one of the important antioxidant marker for diagnostic potential and candidate for chemoprevention.

METHODS

We measured activity of antioxidant enzyme GST, levels of lipid peroxidation and catalase activity during vivax infection.

RESULTS

Mean activity of antioxidant enzyme GST in patients serum and plasma were less (6.43 and 5.65 IU/L respectively) than healthy subjects (11.65 and 10.09 IU/L respectively). Lipid peroxidation level and catalase activity of patients (1.77 micromol/L and 29.64 U/mL) with vivax malaria were higher than those of healthy subjects (1.03 micromol/L and 10.87 U/mL). GST activity in serum and plasma was inversely correlated with age in case of vivax patient and were found significant (R2=0.1907 and 0.1605 and p<0.0007 and p<0.01).

CONCLUSIONS

In view of the present findings we suggest that GST, lipid peroxidation and catalase evaluation may be considered to be reliable biochemical markers and possess promising rational for diagnostic and therapeutic potential in vivax malaria. Decreasing GST activity and elevated activity of lipid peroxidation and catalase may play important roles in host defence mechanisms against vivax infection by up-regulating oxidative defence mechanisms.

Evaluation of antioxidant status and oxidative stress in cattle naturally infected with Theileria annulata

To assess the antioxidant status and oxidative stress in bovine theileriosis due to Theileria annulata blood samples were collected from 35 clinically affected cattle referred to Veterinary Teaching Hospital, School of Veterinary Medicine, Urmia University, Urmia, Iran. Complete blood count, piroplasm parasitemia percentage, erythrocyte glutathione peroxidase, superoxide dismutase, catalase and glucose-6-phosphate dehydrogenase activities, malondialdehyde concentration, osmotic fragility test and median corpuscular fragility were determined and the results were compared with those of 50 healthy controls. Of 35 affected cattle, 12 (34.28%) had severe anemia and 23 had mild to moderate anemia and parasitemia varied from 5 to 40%. The activities of erythrocyte glutathione peroxidase, superoxide dismutase and glucose-6-phosphate dehydrogenase were significantly lower (P<0.0001) and the activity of catalase was significantly higher in the affected cattle than in healthy ones (P<0.001). Malondialdehyde concentration in erythrocytes of affected cattle was significantly more than those of healthy cattle (P<0.001). The affected cattle showed increased fragility of erythrocytes, so that median corpuscular fragility (MCF) in affected group was significantly lower than those of healthy group (P<0.0001). Median corpuscular fragility showed a positive correlation with the severity of parasitemia (r=0.81, P<0.0005) and a negative correlation with the activities of GSH-Px (r=-0.78, P<0.0001), SOD (r=-0.71, P<0.0005), catalase (r=-0.53, P<0.018) and G6PD (r=-0.58, P<0.0005). The results of this study suggest that oxidative damage to RBCs may contribute to the pathogenesis of anemia in bovine theileriosis.

Lymphatic filariasis: possible pathophysiological nexus with oxidative stress

Wuchereria bancrofti-mediated lymphatic filariasis is widely prevalent. Diversity in immune response presumably may lead to myriad clinical presentations, such as overt chronic filariasis, occult filariasis with atypical systemic manifestation and asymptomatic microfilariae carrier state. Anticipated oxidative stress during inflammatory response to infective conditions might complicate the immune response and thus might alter the disease outcome. The present study was carried out to assess the status of oxidative stress in different clinical presentations of bancroftian filariasis. Twenty-five microfilariae carriers and 30 cases each of chronic filariasis and occult filariasis were compared to 30 endemic normal individuals. Serum malondialdehyde level and superoxide dismutase enzyme activity were measured by spectrophotometric methods and levels of filarial antigen were measured by ELISA. In the filarial cases, the levels of these parameters were assayed again after treatment with diethylcarbamazine citrate (DEC). Results showed significant (P<0.05) association of oxidative stress with chronic and occult filariasis but not with microfilarial carriers. DEC therapy in both clinical cases and carriers resulted in a significant reduction of oxidative stress associated with decreased antigen level (P<0.01). These findings suggest the possible involvement of oxidative stress in filarial disease pathology.

Apoptosis in liver during malaria: role of oxidative stress and implication of mitochondrial pathway

Hepatic dysfunction is a common clinical complication in malaria, although its pathogenesis remains largely unknown. Using a variety of in vivo and ex vivo approaches, we have shown for the first time that malarial infection induces hepatic apoptosis through augmentation of oxidative stress. Apoptosis in hepatocyte has been confirmed by terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-biotin-nick-end labeling assay (TUNEL) and caspase-3 activation. Gene expression analysis using RT-PCR indicates the significant down-regulation of Bcl-2 and up-regulation of Bax expression in liver of malaria infected mice suggesting the involvement of mitochondrial pathway of apoptosis. The levels of Fas expression and caspase-8 activity in infected liver were same as that of uninfected control mice indicating death receptor (Fas) pathway did not contribute to liver apoptosis during malarial infection. Moreover, evidence has been presented by confocal microscopy to show the translocation of Bax from cytosol to mitochondria in apoptotic hepatocyte, resulting in opening of permeability transition pores, which in turn decreases mitochondrial membrane potential and induces cytochrome c release into cytosol. Malarial infection induces the generation of hydroxyl radical (*OH) in liver, which may be responsible for the induction of oxidative stress and apoptosis as administration of *OH specific antioxidant as well as spin trap, alpha-phenyl-tert-butyl-nitrone in malaria-infected mice significantly inhibits the development of oxidative stress as well as induction of apoptosis. Thus, results suggest the implication of oxidative stress induced-mitochondrial pathway of apoptosis in the pathophysiology of hepatic dysfunction in malaria.