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Gan B, Yu L, Yang H, Jiao H, Pang B, Chen Y, Wang C, Lv R, Hu H, Cao Z, Ren R. Mechanism of agonist-induced activation of the human itch receptor MRGPRX1. PLoS Biol 2023; 21:e3001975. [PMID: 37347749 DOI: 10.1371/journal.pbio.3001975] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Accepted: 05/31/2023] [Indexed: 06/24/2023] Open
Abstract
Mas-related G-protein-coupled receptors X1-X4 (MRGPRX1-X4) are 4 primate-specific receptors that are recently reported to be responsible for many biological processes, including itch sensation, pain transmission, and inflammatory reactions. MRGPRX1 is the first identified human MRGPR, and its expression is restricted to primary sensory neurons. Due to its dual roles in itch and pain signaling pathways, MRGPRX1 has been regarded as a promising target for itch remission and pain inhibition. Here, we reported a cryo-electron microscopy (cryo-EM) structure of Gq-coupled MRGPRX1 in complex with a synthetic agonist compound 16 in an active conformation at an overall resolution of 3.0 Å via a NanoBiT tethering strategy. Compound 16 is a new pain-relieving compound with high potency and selectivity to MRGPRX1 over other MRGPRXs and opioid receptor. MRGPRX1 was revealed to share common structural features of the Gq-mediated receptor activation mechanism of MRGPRX family members, but the variable residues in orthosteric pocket of MRGPRX1 exhibit the unique agonist recognition pattern, potentially facilitating to design MRGPRX1-specific modulators. Together with receptor activation and itch behavior evaluation assays, our study provides a structural snapshot to modify therapeutic molecules for itch relieving and analgesia targeting MRGPRX1.
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Affiliation(s)
- Bing Gan
- Shanghai Key Laboratory of Metabolic Remodeling and Health, Institute of Metabolism and Integrative Biology, Fudan University, Shanghai, China
- The Kobilka Institute of Innovative Drug Discovery, School of Medicine, The Chinese University of Hong Kong, Shenzhen, Guangdong, China
| | - Leiye Yu
- Shanghai Key Laboratory of Metabolic Remodeling and Health, Institute of Metabolism and Integrative Biology, Fudan University, Shanghai, China
| | - Haifeng Yang
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
- Shenzhen Research Institute, Wuhan University, Shenzhen, China
| | - Haizhan Jiao
- The Kobilka Institute of Innovative Drug Discovery, School of Medicine, The Chinese University of Hong Kong, Shenzhen, Guangdong, China
| | - Bin Pang
- Shanghai Key Laboratory of Metabolic Remodeling and Health, Institute of Metabolism and Integrative Biology, Fudan University, Shanghai, China
| | - Yian Chen
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
| | - Chen Wang
- Shanghai Key Laboratory of Metabolic Remodeling and Health, Institute of Metabolism and Integrative Biology, Fudan University, Shanghai, China
| | - Rui Lv
- Shanghai Key Laboratory of Metabolic Remodeling and Health, Institute of Metabolism and Integrative Biology, Fudan University, Shanghai, China
| | - Hongli Hu
- The Kobilka Institute of Innovative Drug Discovery, School of Medicine, The Chinese University of Hong Kong, Shenzhen, Guangdong, China
| | - Zhijian Cao
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
- Shenzhen Research Institute, Wuhan University, Shenzhen, China
| | - Ruobing Ren
- Shanghai Key Laboratory of Metabolic Remodeling and Health, Institute of Metabolism and Integrative Biology, Fudan University, Shanghai, China
- Shanghai Qi Zhi Institute, Shanghai, China
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Rg3-enriched Korean red ginseng alleviates chloroquine-induced itch and dry skin pruritus in an MrgprA3-dependent manner in mice. Integr Med Res 2023; 12:100916. [PMID: 36632132 PMCID: PMC9826840 DOI: 10.1016/j.imr.2022.100916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 11/11/2022] [Accepted: 12/14/2022] [Indexed: 12/24/2022] Open
Abstract
Background Previous studies have found that Korean red ginseng extract (KRG) has antipruritic effects, which can be attributed to the presence of Rg3, one of the most potent ginsenosides. Therefore, Rg3-enriched KRG extract (Rg3EKRG) is anticipated to have enhanced antipruritic effects. The present study was conducted to examine the effects of Rg3EKRG in acute chloroquine (CQ)-induced and chronic dry skin pruritus. Methods Calcium imaging technique was used in HE293T cells expressing MrgprA3 and TRPA1 ("MrgprA3/TRPA1") and in primary cultures of mouse dorsal root ganglia (DRG) neurons. Mouse scratching behavior tests were performed on dry skin models. To verify the altered expression of itch-related genes, real-time RNA sequencing analysis and PCR were performed on DRG sections obtained from dry skin models. Results Rg3EKRG suppressed CQ-induced intracellular calcium changes to a greater degree than KRG. Rg3EKRG dose-dependently inhibited CQ-induced responses in MrgprA3/TRPA1 cells. Rg3EKRG likely targeted MrgprA3 rather than TRPA1 to exert its inhibitory effect. Further, Rg3EKRG strongly inhibited the scratching behavior in mice induced by acute CQ injection. Importantly, DRG neurons obtained from dry skin mice models showed increased mRNA levels of MrgprA3, and treatment with Rg3EKRG alleviated chronic dry skin conditions and suppressed spontaneous scratching behaviors. Conclusion The results of the present study imply that Rg3EKRG has a stronger antipruritic effect than KRG, inhibiting both acute CQ-induced and chronic dry skin pruritus in an MrgprA3-dependent manner. Therefore, Rg3EKRG is a potential antipruritic agent that can suppress acute and chronic itching at the peripheral sensory neuronal level.
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Korean Red Ginseng extract and ginsenoside Rg3 have anti-pruritic effects on chloroquine-induced itch by inhibition of MrgprA3/TRPA1-mediated pathway. J Ginseng Res 2017; 42:470-475. [PMID: 30337807 PMCID: PMC6187082 DOI: 10.1016/j.jgr.2017.05.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Accepted: 05/12/2017] [Indexed: 01/04/2023] Open
Abstract
Background It was previously found that Korean Red Ginseng water extract (KRGE) inhibits the histamine-induced itch signaling pathway in peripheral sensory neurons. Thus, in the present study, we investigated whether KRGE inhibited another distinctive itch pathway induced by chloroquine (CQ); a representative histamine-independent pathway mediated by MrgprA3 and TRPA1. Methods Intracellular calcium changes were measured by the calcium imaging technique in the HEK293T cells transfected with both MrgprA3 and TRPA1 ("MrgprA3/TRPA1"), and in primary culture of mouse dorsal root ganglia (DRGs). Mouse scratching behavior tests were performed to verify proposed antipruritic effects of KRGE and ginsenoside Rg3. Results CQ-induced Ca2+ influx was strongly inhibited by KRGE (10 μg/mL) in MrgprA3/TRPA1, and notably ginsenoside Rg3 dose-dependently suppressed CQ-induced Ca2+ influx in MrgprA3/TRPA1. Moreover, both KRGE (10 μg/mL) and Rg3 (100 μM) suppressed CQ-induced Ca2+ influx in primary culture of mouse DRGs, indicating that the inhibitory effect of KRGE was functional in peripheral sensory neurons. In vivo tests revealed that not only KRGE (100 mg) suppressed CQ-induced scratching in mice [bouts of scratching: 274.0 ± 51.47 (control) vs. 104.7 ± 17.39 (KRGE)], but also Rg3 (1.5 mg) oral administration significantly reduced CQ-induced scratching as well [bouts of scratching: 216.8 ± 33.73 (control) vs. 115.7 ± 20.94 (Rg3)]. Conclusion The present study verified that KRGE and Rg3 have a strong antipruritic effect against CQ-induced itch. Thus, KRGE is as a promising antipruritic agent that blocks both histamine-dependent and -independent itch at peripheral sensory neuronal levels.
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Moser HR, Giesler GJ. Characterization of pruriceptive trigeminothalamic tract neurons in rats. J Neurophysiol 2014; 111:1574-89. [PMID: 24478156 PMCID: PMC4035772 DOI: 10.1152/jn.00668.2013] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Accepted: 01/22/2014] [Indexed: 11/22/2022] Open
Abstract
Rodent models of facial itch and pain provide a valuable tool for distinguishing between behaviors related to each sensation. In rats, pruritogens applied to the face elicit scratching using the hindlimb while algogens elicit wiping using the forelimb. We wished to determine the role of trigeminothalamic tract (VTT) neurons in carrying information regarding facial itch and pain to the forebrain. We have characterized responses to facially applied pruritogens (serotonin, BAM8-22, chloroquine, histamine, capsaicin, and cowhage) and noxious stimuli in 104 VTT neurons recorded from anesthetized rats. Each VTT neuron had a mechanically sensitive cutaneous receptive field on the ipsilateral face. All pruriceptive VTT neurons also responded to noxious mechanical and/or thermal stimulation. Over half of VTT neurons responsive to noxious stimuli also responded to at least one pruritogen. Each tested pruritogen, with the exception of cowhage, produced an increase in discharge rate in a subset of VTT neurons. The response to each pruritogen was characterized, including maximum discharge rate, response duration, and spike timing dynamics. Pruriceptive VTT neurons were recorded from throughout superficial and deep layers of the spinal trigeminal nucleus and were shown to project via antidromic mapping to the ventroposterior medial nucleus or posterior thalamic nuclei. These results indicate that pruriceptive VTT neurons are a subset of polymodal nociceptive VTT neurons and characterize a system conducive to future experiments regarding the similarities and differences between facial itch and pain.
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Affiliation(s)
- Hannah R Moser
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota
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Patel KN, Liu Q, Meeker S, Undem BJ, Dong X. Pirt, a TRPV1 modulator, is required for histamine-dependent and -independent itch. PLoS One 2011; 6:e20559. [PMID: 21655234 PMCID: PMC3105090 DOI: 10.1371/journal.pone.0020559] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2011] [Accepted: 05/03/2011] [Indexed: 12/14/2022] Open
Abstract
Itch, or pruritus, is an important clinical problem whose molecular basis has yet to be understood. Recent work has begun to identify genes that contribute to detecting itch at the molecular level. Here we show that Pirt, known to play a vital part in sensing pain through modulation of the transient receptor potential vanilloid 1 (TRPV1) channel, is also necessary for proper itch sensation. Pirt−/− mice exhibit deficits in cellular and behavioral responses to various itch-inducing compounds, or pruritogens. Pirt contributes to both histaminergic and nonhistaminergic itch and, crucially, is involved in forms of itch that are both TRPV1-dependent and -independent. Our findings demonstrate that the function of Pirt extends beyond nociception via TRPV1 regulation to its role as a critical component in several itch signaling pathways.
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Affiliation(s)
- Kush N. Patel
- The Solomon H. Snyder Department of Neuroscience, Center for Sensory Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Qin Liu
- The Solomon H. Snyder Department of Neuroscience, Center for Sensory Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Sonya Meeker
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Bradley J. Undem
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Xinzhong Dong
- The Solomon H. Snyder Department of Neuroscience, Center for Sensory Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Howard Hughes Medical Institute, Chevy Chase, Maryland, United States of America
- * E-mail:
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Abstract
The itch field has made great advances in recent years, building upon earlier work to form a clearer picture of the biology behind this important sensory modality. Models for how itch is encoded have emerged that fit with physiological, molecular, and behavioral data. The molecular mechanisms of itch, both peripherally and centrally, are being revealed with the aid of newer animal models. Future work must address shortcomings in our current understanding of itch including limitations of current experimental methods. Here we review what is known about the cells, molecules, and circuits involved in itch and highlight key questions that remain to be answered.
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Affiliation(s)
- Kush N. Patel
- The Solomon H. Snyder Department of Neuroscience, Center for Sensory Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
| | - Xinzhong Dong
- The Solomon H. Snyder Department of Neuroscience, Center for Sensory Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
- Howard Hughes Medical Institute, Chevy Chase, Maryland 20815, United States
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Liu Q, Tang Z, Surdenikova L, Kim S, Patel KN, Kim A, Ru F, Guan Y, Weng HJ, Geng Y, Undem BJ, Kollarik M, Chen ZF, Anderson DJ, Dong X. Sensory neuron-specific GPCR Mrgprs are itch receptors mediating chloroquine-induced pruritus. Cell 2009; 139:1353-65. [PMID: 20004959 PMCID: PMC2989405 DOI: 10.1016/j.cell.2009.11.034] [Citation(s) in RCA: 575] [Impact Index Per Article: 38.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2008] [Revised: 09/14/2009] [Accepted: 11/04/2009] [Indexed: 12/13/2022]
Abstract
The cellular and molecular mechanisms mediating histamine-independent itch in primary sensory neurons are largely unknown. Itch induced by chloroquine (CQ) is a common side effect of this widely used antimalarial drug. Here, we show that Mrgprs, a family of G protein-coupled receptors expressed exclusively in peripheral sensory neurons, function as itch receptors. Mice lacking a cluster of Mrgpr genes display significant deficits in itch induced by CQ but not histamine. CQ directly excites sensory neurons in an Mrgpr-dependent manner. CQ specifically activates mouse MrgprA3 and human MrgprX1. Loss- and gain-of-function studies demonstrate that MrgprA3 is required for CQ responsiveness in mice. Furthermore, MrgprA3-expressing neurons respond to histamine and coexpress gastrin-releasing peptide, a peptide involved in itch sensation, and MrgprC11. Activation of these neurons with the MrgprC11-specific agonist BAM8-22 induces itch in wild-type but not mutant mice. Therefore, Mrgprs may provide molecular access to itch-selective neurons and constitute novel targets for itch therapeutics.
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Affiliation(s)
- Qin Liu
- The Solomon H. Snyder Department of Neuroscience, Center for Sensory Biology, Johns Hopkins University, School of Medicine, Baltimore, MD 21205
| | - Zongxiang Tang
- The Solomon H. Snyder Department of Neuroscience, Center for Sensory Biology, Johns Hopkins University, School of Medicine, Baltimore, MD 21205
| | - Lenka Surdenikova
- Department of Medicine, Johns Hopkins University, School of Medicine, Baltimore, MD 21205
- Department of Pathophysiology, Jessenius Medical School, Martin, Slovakia
| | - Seungil Kim
- Departments of Anesthesiology, Psychiatry, and Developmental Biology, Washington University School of Medicine Pain Center, St. Louis, MO 63110
| | - Kush N. Patel
- The Solomon H. Snyder Department of Neuroscience, Center for Sensory Biology, Johns Hopkins University, School of Medicine, Baltimore, MD 21205
| | - Andrew Kim
- The Solomon H. Snyder Department of Neuroscience, Center for Sensory Biology, Johns Hopkins University, School of Medicine, Baltimore, MD 21205
| | - Fei Ru
- Department of Medicine, Johns Hopkins University, School of Medicine, Baltimore, MD 21205
| | - Yun Guan
- Department of Anesthesiology & Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, MD 21205
| | - Hao-Jui Weng
- The Solomon H. Snyder Department of Neuroscience, Center for Sensory Biology, Johns Hopkins University, School of Medicine, Baltimore, MD 21205
| | - Yixun Geng
- The Solomon H. Snyder Department of Neuroscience, Center for Sensory Biology, Johns Hopkins University, School of Medicine, Baltimore, MD 21205
| | - Bradley J. Undem
- Department of Medicine, Johns Hopkins University, School of Medicine, Baltimore, MD 21205
| | - Marian Kollarik
- Department of Medicine, Johns Hopkins University, School of Medicine, Baltimore, MD 21205
| | - Zhou-Feng Chen
- Departments of Anesthesiology, Psychiatry, and Developmental Biology, Washington University School of Medicine Pain Center, St. Louis, MO 63110
| | - David J. Anderson
- Division of Biology, California Institute of Technology, Pasadena, CA 91125
- Howard Hughes Medical Institute
| | - Xinzhong Dong
- The Solomon H. Snyder Department of Neuroscience, Center for Sensory Biology, Johns Hopkins University, School of Medicine, Baltimore, MD 21205
- Howard Hughes Medical Institute
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Ogungbamigbe TO, Ojurongbe O, Ogunro PS, Okanlawon BM, Kolawole SO. Chloroquine resistant Plasmodium falciparum malaria in Osogbo Nigeria: efficacy of amodiaquine + sulfadoxine-pyrimethamine and chloroquine + chlorpheniramine for treatment. Mem Inst Oswaldo Cruz 2008; 103:79-84. [PMID: 18368238 DOI: 10.1590/s0074-02762008000100012] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2007] [Accepted: 02/18/2008] [Indexed: 11/22/2022] Open
Abstract
Chloroquine (CQ) resistance in Plasmodium falciparum contributes to increasing malaria-attributable morbidity and mortality in Sub-Saharan Africa. Despite a change in drug policy, continued prescription of CQ did not abate. Therefore the therapeutic efficacy of CQ in uncomplicated falciparum malaria patients was assessed in a standard 28-day protocol in 116 children aged between six and 120 months in Osogbo, Southwest Nigeria. Parasitological and clinical assessments of response to treatment showed that 72 (62.1%) of the patients were cured and 44 (37.9%) failed the CQ treatment. High initial parasite density and young age were independent predictors for early treatment failure. Out of the 44 patients that failed CQ, 24 received amodiaquine + sulphadoxine/pyrimethamine (AQ+SP) and 20 received chlorpheniramine + chloroquine (CH+CQ) combinations. Mean fever clearance time in those treated with AQ+SP was not significantly different from those treated with CH+CQ (p = 0.05). There was no significant difference in the mean parasite density of the two groups. The cure rate for AQ+SP group was 92% while those of CH+CQ was 85%. There was a significant difference in parasite clearance time (p = 0.01) between the two groups. The 38% treatment failure for CQ reported in this study is higher than the 10% recommended by World Health Organization in other to effect change in antimalarial treatment policy. Hence we conclude that CQ can no more be solely relied upon for the treatment of falciparum malaria in Osogbo, Nigeria. AQ+SP and CH+CQ are effective in the treatment of acute uncomplicated malaria and may be considered as useful alternative drugs in the absence of artemisinin-based combination therapies.
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Affiliation(s)
- T O Ogungbamigbe
- Malaria Research Clinic & Laboratory, College of Health Sciences, Ladoke Akintola University Teaching Hospital, Osogbo, Nigeria
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Sowunmi A, Falade A, Adedeji A, Ayede A, Fateye B, Sowunmi C, Oduola A. Comparative Plasmodium falciparum Kinetics during Treatment with Amodiaquine and Chloroquine in Children. Clin Drug Investig 2001. [DOI: 10.2165/00044011-200121050-00007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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Sowunmi A, Adedeji AA, Sowunmi CO, Falade CO, Falade AG, Ohaeri B, Happi TC, Oduola AMJ. Clinical characteristics and disposition kinetics of the hepatomegaly associated with acute, uncomplicated, Plasmodium falciparummalaria in children. ANNALS OF TROPICAL MEDICINE AND PARASITOLOGY 2001. [DOI: 10.1080/00034983.2001.11813610] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Sowunmi A, Adedeji AA, Sowunmi CO, Falade AG, Sijuade AO, Oduola AM. Comparative clinical characteristics and response to oral antimalarial therapy of children with and without Plasmodium falciparum hyperparasitaemia in an endemic area. ANNALS OF TROPICAL MEDICINE AND PARASITOLOGY 2000; 94:549-58. [PMID: 11064756 DOI: 10.1080/00034983.2000.11813577] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The clinical characteristics and the responses to oral antimalarial therapy of 104 children presenting consecutively with or without Plasmodium falciparum hyperparasitaemia (HP) were investigated in an endemic area. At presentation, although the 52 children with HP were significantly younger and had significantly higher heart rates than the 52 without, there were no significant differences between the two groups in their symptoms or in any other clinical feature of their malaria. Responses to oral antimalarial drugs were similar in both groups. Analysis of the disposition kinetics of parasitaemia, using a non-compartmental model similar to that used in characterizing drug disposition, showed that the two groups had similar half-lives of parasitaemia (t1/2pd), volumes of blood completely cleared of parasites per unit time (CLBpd), and parasite-clearance-time:t1/2pd ratios. Three children in the HP group, all aged < 3 years, progressed to cerebral malaria within 8 h of presentation, and another HP child presented with isolated trunkal ataxia, indicative of cerebellar involvement. No child in the non-HP group had any of the features of severe malaria. Although the clinical characteristics and responses to oral therapy of children with and without HP are therefore very similar, young children with HP appear to have an increased risk of developing other features of severe malaria.
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Affiliation(s)
- A Sowunmi
- Department of Pharmacology and Therapeutics, University of Ibadan, Nigeria.
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