THE RAPID CURE OF AMOEBIC DYSENTERY AND HEPATITIS BY HYPODERMIC INJECTIONS OF SOLUBLE SALTS OF EMETINE

Emetine Is Not Ipecac: Considerations for Its Use as Treatment for SARS-CoV2

Emetine is a potent antiviral that acts on many viruses in the low-nM range, with several studies in animals and humans demonstrating antiviral activity. Historically, emetine was used to treat patients with Spanish influenza, in the last stages of the pandemic in the early 1900s. Some of these patients were "black" with cyanosis. Emetine rapidly reversed the cyanosis and other symptoms of this disease in 12-24 h. However, emetine also has been shown to have anti-inflammatory properties and it appears it is these anti-inflammatory properties that were responsible for the effects seen in patients with Spanish influenza. Emetine, in the past, has also been used in 10s to 100s of millions of people at a dose of ~60 mg daily to treat amoebiasis. Based on viral inhibition data we can calculate a likely SARS-CoV2 antiviral dose of ~1/10th the amoebiasis dose, which should dramatically reduce the risk of any side effects. While there are no anti-inflammatory dose response data available, based on the potential mode of action, the anti-inflammatory actions may also occur at low doses. This paper also examines the toxicity of emetine seen in clinical practice and that seen in the laboratory, and discusses the methods of administration aimed at reducing side effects if higher doses were found to be necessary. While emetine is a "pure drug" as it is extracted from ipecac, some of the differences between emetine and ipecac are also discussed.

Lead Optimization of Dehydroemetine for Repositioned Use in Malaria

Drug repositioning offers an effective alternative to de novo drug design to tackle the urgent need for novel antimalarial treatments. The antiamoebic compound emetine dihydrochloride has been identified as a potent in vitro inhibitor of the multidrug-resistant strain K1 of Plasmodium falciparum (50% inhibitory concentration [IC₅₀], 47 nM ± 2.1 nM [mean ± standard deviation]). Dehydroemetine, a synthetic analogue of emetine dihydrochloride, has been reported to have less-cardiotoxic effects than emetine.

Drug repositioning offers an effective alternative to de novo drug design to tackle the urgent need for novel antimalarial treatments. The antiamoebic compound emetine dihydrochloride has been identified as a potent in vitro inhibitor of the multidrug-resistant strain K1 of Plasmodium falciparum (50% inhibitory concentration [IC₅₀], 47 nM ± 2.1 nM [mean ± standard deviation]). Dehydroemetine, a synthetic analogue of emetine dihydrochloride, has been reported to have less-cardiotoxic effects than emetine. The structures of two diastereomers of dehydroemetine were modeled on the published emetine binding site on the cryo-electron microscopy (cryo-EM) structure with PDB code 3J7A (P. falciparum 80S ribosome in complex with emetine), and it was found that (−)-R,S-dehydroemetine mimicked the bound pose of emetine more closely than did (−)-S,S-dehydroisoemetine. (−)-R,S-dehydroemetine (IC₅₀ 71.03 ± 6.1 nM) was also found to be highly potent against the multidrug-resistant K1 strain of P. falciparum compared with (−)-S,S-dehydroisoemetine (IC₅₀, 2.07 ± 0.26 μM), which loses its potency due to the change of configuration at C-1′. In addition to its effect on the asexual erythrocytic stages of P. falciparum, the compound exhibited gametocidal properties with no cross-resistance against any of the multidrug-resistant strains tested. Drug interaction studies showed (−)-R,S-dehydroemetine to have synergistic antimalarial activity with atovaquone and proguanil. Emetine dihydrochloride and (−)-R,S-dehydroemetine failed to show any inhibition of the hERG potassium channel and displayed activity affecting the mitochondrial membrane potential, indicating a possible multimodal mechanism of action.

Amebic liver abscess in northern region of Bangladesh: sociodemographic determinants and clinical outcomes

Background

Amebic liver abscess (ALA) is endemic in Bangladesh since historical age but its epidemiology and sociodemographic determinants are not well described in the literatures. This paper focuses on the endemicity, sociodemographic determinants and clinical outcomes of ALA patients from certain northern districts in Bangladesh. Ninety hospitalized ALA patients enrolled from 6 northern districts of Bangladesh during July 2008 to June 2010 were analyzed.

Findings

Clinical presentations of ALA was initially substantiated by ultrasound imaging and later confirmed by detection of small subunit rRNA gene of E. histolytica using a Real Time PCR. Structured questionnaire and data sheet were used to record sociodemographic characteristics, clinical presentations and outcomes. Patients were followed for immediate and late treatment outcomes up to 2 years since diagnosis. Northern districts those situated on the Ganges basin were noted as endemic areas. Male significantly outnumbered the female with a male to female ratio of 21:1 and majority of patients (58%) were in their 3rd and 4th decades. A significant (21%) number of patients were aborigines despite their ethnic minority as population under investigation and overall 68% belonged to low socioeconomic group. Habit of indigenous alcohol consumption was very high (78%) among ALA patients with overwhelming majority was illiterate (74.44%) and from rural population (70%). Fever with right hypochondriac pain of variable duration was the principal presenting complains. Gross fluid derangements including pleural effusion, edema and ascities were observed in 39% cases and 6% had rupture of abscess. All patients were treated with standard antimicrobial regimen and discharged with initial recovery. Recurrent attack was observed in 6% cases and 3 (3.33%) patients died during 2 years follow-up period. Complicated (37.78%) ALA patients showed significant Odds ratio (P < 0.05) for major sociodemographic determinants in comparison to non-complicated patients.

Conclusions

Amebic liver abscess is endemic in certain northern districts of Bangladesh especially on the Ganges basin with relatively high prevalence among aborigines. Rural habitat, ethnicity (Aborigine) and habit of indigenous alcohol consumption were found to be strong determinants, especially for complicated ALA, which were associated with different grades of morbidity and a few mortalities.

Schistosomiasis chemotherapy

After malaria, schistosomiasis (or bilharzia) is the second most prevalent disease in Africa, and is occurring in over 70 countries in tropical and subtropical regions. It is estimated that 600 million people are at risk of infection, 200 million people are infected, and at least 200,000 deaths per year are associated with the disease. All schistosome species are transmitted through contact with fresh water that is infested with free-swimming forms of the parasite, which is known as cercariae and produced by snails. When located in the blood vessels of the host, larval and adult schistosomes digest red cells to acquire amino acids for growth and development. Vaccine candidates have been unsuccessful up to now. Against such devastating parasitic disease, the antischistosomal arsenal is currently limited to a single drug, praziquantel, which has been used for more than 35 years. Because the question of the reduction of the activity of praziquantel was raised recently, it is thus urgent to create new and safe antischistosomal drugs that should be combined with praziquantel to develop efficient bitherapies.

Laboratory diagnosis of amebiasis

The detection of Entamoeba histolytica, the causative agent of amebiasis, is an important goal of the clinical microbiology laboratory. To assess the scope of E. histolytica infection, it is necessary to utilize accurate diagnostic tools. As more is discovered about the molecular and cell biology of E. histolytica, there is great potential for further understanding the pathogenesis of amebiasis. Molecular biology-based diagnosis may become the technique of choice in the future because establishment of these protozoa in culture is still not a routine clinical laboratory process. In all cases, combination of serologic tests with detection of the parasite (by antigen detection or PCR) offers the best approach to diagnosis, while PCR techniques remain impractical in many developing country settings. The detection of amebic markers in serum in patients with amebic colitis and liver abscess appears promising but is still only a research tool. On the other hand, stool antigen detection tests offer a practical, sensitive, and specific way for the clinical laboratory to detect intestinal E. histolytica. All the current tests suffer from the fact that the antigens detected are denatured by fixation of the stool specimen, limiting testing to fresh or frozen samples.

A review of plant species assessed in vitro for antiamoebic activity or both antiamoebic and antiplasmodial properties

The resurgence of the protozoal diseases amoebiasis and malaria has been known to occur, from time to time, in endemic and epidemic proportions all over the world. Furthermore, the import of these individual pathogens to other areas from tropical regions encourages these protozoal diseases to occur on a global scale with considerable associated mortality and morbidity. From time immemorial, the cure of these diseases has been attempted with the use of traditional plant products, derived from such species as are available within local habitats and ecosystems, and dependent on their host community for their conservation. Scientific validation and in vitro investigation, continues to be an important requirement for drug development, particularly with the emergence of resistance and cross resistance to some standard drugs used in such protozoal diseases. This paper provides a comparative compilation of the various studies reported between 1982 and 1999, on plants with antiamoebic activities and those which possess both antiamoebic and antiplasmodial activities. The results suggest that it is advisable to increase efforts towards the conservation of such plants, in order to retain their economic and therapeutic significance.

Recent advances in amebiasis

Advancements in our understanding of amebiasis have been rapid over the decade that I have followed this field. What was identified morphologically for years as Entamoeba histolytica has been redescribed with modern techniques as a complex of two species, the commensal parasite E. dispar and the pathogenic parasite E. histolytica that is the cause of colitis and liver abscess. Antigen detection tests are now available for the rapid detection in stool of the pathogenic species E. histolytica. New understandings of the importance of luminal as well as tissue-active antimebic medications in the treatment of invasive disease have been reached. The groundwork is being laid for an understanding of the protective immune responses to infection, and at the lab bench DNA transfection of the parasite has opened studies of pathogenesis to genetic analysis. While necessarily an incomplete sketch of the field, I have attempted here to highlight some recent and important developments of interest to clinicians and microbiologists.

Toxicology of ipecac: a review

The general effectiveness and safety of Ipecac syrup, per se, has not been questioned, but rather an attempt has been made to consolidate pertinent literature dealing with the toxic manifestations of Ipecac fluid extract. Ipecac contains both emetine and cephaeline and the toxicity of Ipecac fluid extract is consistent with reports on the toxicity of both compounds. The majority of the work has involved emetine since it is in higher concentration in Ipecac fluid extract than is cephaeline. Comparison of the clinical picture presented in syrup or fluid extract of Ipecac overdose and emetine toxicity in amebiasis treatment permits us to summarize the general characteristics of Ipecac alkaloid toxicity as involving primarily gastrointestinal, cardiovascular, and neuromuscular foci.