Artemisinins from folklore to modern medicine--transforming an herbal extract to life-saving drugs.

The history of the artemisinins from Ge Hong in China during the 4th century, to the re-discovery of the qing hao derivatives in the 1970s, to the explosion of artemisinin derivatives and combinations throughout the world today is a fascinating story. The central and underappreciated role of the United States Army's 'drug company' known as the Division of Experimental Therapeutics at the Walter Reed Army Institute of Research is a story worth relating. From being the first group outside China to extract the active component of qing hao, to leading the work on neurotoxicity of the class in animals, to bringing a Good Manufacturing Practices intravenous formulation to the worldwide market is traced.

Pathogen inactivation of Leishmania donovani infantum in plasma and platelet concentrates using riboflavin and ultraviolet light.

BACKGROUND AND OBJECTIVES: Leishmania is transmitted by the bite of the phlebotomine sandfly or by transfusion of infected blood products. Leishmaniasis currently poses a significant problem in several parts of the world, and is an emerging problem in others. The Mirasol PRT technology is based on the use of riboflavin and ultraviolet light to generate chemical reactions in the nucleic acids of pathogens, which prevents replication and leads to inactivation. The intent of this study was to examine the ability of the Mirasol PRT System to kill the Leishmania parasite in human plasma and platelet concentrates. MATERIALS AND METHODS: In visceral Leishmaniasis, amastigotes are present in the blood and in the reticuloendothelial system within monocytes. For each unit of plasma or platelets treated, isolated mononuclear cells obtained from 100 ml of normal donor whole blood were incubated with 1.0 x 10(8) Leishmania donovani infantum promastigotes to produce amastigote-laden macrophages. The infected macrophages were added to 250 ml of human plasma or to 250 ml of platelet concentrates. Infected units were cultured pretreatment in 10-fold serial dilutions to determine the limits of detection. Thirty millilitres of 500 microM riboflavin was added to each unit, which was then illuminated with 5.9 J/cm2 of ultraviolet light (6.24 J/ml). After treatment and after 2 months of frozen storage, plasma units were cultured in 10-fold serial dilutions. Platelets were cultured on the day of treatment and on day 5 of storage post-illumination. RESULTS: A 5 log reduction of Leishmania was demonstrated in five of six units of plasma, and a 7 log reduction of Leishmania was demonstrated in one plasma unit. A 5 log reduction of Leishmania was demonstrated in five of six units of platelets, and a 6 log reduction of Leishmania was demonstrated in one unit. CONCLUSIONS: There is no donor screen for Leishmania and other pathogens constantly emerging in our blood supply. The Mirasol PRT System for Platelets and Plasma is an effective means of killing Leishmania and other emerging pathogens in these blood products.

From atabrine in World War II to mefloquine in Somalia: the role of education in preventive medicine.

Preventive medicine requires an understanding not only of the disease to be prevented, but a complete understanding of conditions affecting the disease transmission, human nature, and the historic situation of the target group. An analysis of a new drug introduction (Atabrine) during World War II is viewed from multiple perspectives and is compared with the introduction of mefloquine during the mission to Somalia 50 years later. Common themes of educational failure at the end-user and policy-marker levels are shown as barriers to effective preventive medicine efforts.

Comparison of tribromoethanol, ketamine/acetylpromazine, Telazol/xylazine, pentobarbital, and methoxyflurane anesthesia in HSD:ICR mice.

Variation in the duration of surgical anesthesia in mice prompted an evaluation of various commonly used anesthetics. Using biotelemetric technology, we evaluated the effects of six anesthetic regimens (tribromoethanol, ketamine and acetylpromazine in combination, Telazol and xylazine in two combinations, pentobarbital, and methoxyflurane) on temperature and activity. Six groups of four male HSD:ICR mice received one of the anesthetic regimens or an equivalent volume of saline. Induction time (time from anesthetic administration until righting reflex loss) and duration of anesthesia (loss of response to interdigital toe pinch) were evaluated. Methoxyflurane and both doses of Telazol combinations resulted in the shortest and most repeatable induction times. None of the mice in the ketamine/acetylpromazine- and pentobarbital-treated groups lost the interdigital toe pinch reflex. Duration of anesthesia was superior in the two Telazol/xylazine-treated groups. A direct correlation existed between duration of anesthesia and magnitude and duration of temperature reduction. Duration of anesthesia can be used to predict extent of hypothermia.

Fatal neurotoxicity of arteether and artemether.

Artemisinin (qinghaosu) and several derivatives have been developed and are in use as antimalarial drugs but scant information is available regarding animal or human toxicity. Following a eight-day, multiple-dose, pharmacokinetic study of arteether (AE) (10 mg/kg/day [n = 6] and 20 mg/kg/day [n = 6]) in dogs, all high-dose animals displayed a progressive syndrome of clinical neurologic defects with progressive cardiorespiratory collapse and death in five of six animals. Neurologic findings included gait disturbances, loss of spinal and pain response reflexes, and prominent loss of brain stem and eye reflexes. Animals had prolongation of QT interval corrected for rate (QTc) on electrocardiograms (ECGs) with bizarre ST-T segment changes. Prominent neuropathic lesions were noted to be primarily limited to the pons and medulla. Similar lesions with dose-related severity were noted in eight other dogs studied in a second study with intramuscular (IM) administration of AE in sesame oil during a 28-day, dose-ranging study using 5, 10, 15, and 20 mg/kg/day. Injury, graded by a pathologist blinded to the dose group, showed a dose-related, region-specific injury in all animals that was most pronounced in the pons. Further studies in Sprague-Dawley rats using IM administration of AE and artemether (AM) at a dose of 12.5-50 mg/kg/day for 28 days confirmed the onset of a clinical neurologic syndrome with dose-related changes in body weight, activity, and seizure-like activity, stereotypic movement disorders, and ECG changes.(ABSTRACT TRUNCATED AT 250 WORDS)

Neurotoxicity in animals due to arteether and artemether.

Several artemisinin (qinghaosu) derivatives have been developed and are in use as antimalarial drugs but scant animal or human toxicity data are available. We noted a progressive syndrome of clinical neurological defects with cardio-respiratory collapse and death in 5/6 dogs dosed daily for 8 d with intramuscular arteether (AE) at 20 mg/kg/d in a pharmacokinetic study. Neurological findings included gait disturbances, loss of spinal reflexes, pain response reflexes and prominent loss of brain-stem and eye reflexes. Electrocardiography showed prolongation of the QT interval corrected for rate (QTc). Prominent neuropathic lesions were sharply limited to the pons and medulla. Neurological injury, graded by a pathologist 'blinded' to dose group, showed a dose-related region-specific injury which was most pronounced in the pons and medulla in all animals. Rats treated with AE and artemether (AM) at 12.5 to 50 mg/kg/d for 28 d confirmed clinical neurological abnormalities with high doses (> 25 mg/kg/d) after 6-14 d. Neuropathological examination of rat brain sections at 5 levels from the rostral cerebrum to the caudal medulla showed a dose-related pattern of injury characterized by hyalinized neuron cell bodies and loss of Nissl substance; changes congruent with those noted in dogs. No significant difference was noted in the extent, type, or distribution of lesions in the brains of rats treated with equivalent doses of AE or AM.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of butorphanol tartrate and buprenorphine hydrochloride on the inflammatory reaction of the Sereny Test.

Invasion of the ocular epithelia of guinea pigs by virulent Shigella organisms, eliciting keratoconjunctivitis, is the basis of the Sereny Test (ST). This test has been used to ascertain the virulence of Shigella strains and more recently to screen candidate Shigella vaccines for efficacy. This test undoubtedly causes pain in test animals; however, recommendation for use of local analgesics/anesthetics has not been accepted because of concern that these topical agents may affect the ability of the Shigella organisms to invade the ocular epithelia or have a physiologic effect on the inflammatory process. Similarly, investigators are hesitant to use systemic analgesics in conjunction with the ST. Two blinded studies were conducted to evaluate the effects of selected systemic analgesics on the ST in outbred Hartley guinea pigs. Study 1 evaluated the recommended dosages for two systemic analgesics; study groups consisted of those receiving butorphanol tartrate (n = 16), those receiving buprenorphine hydrochloride (n = 16), and untreated controls (n = 5). Study 2 evaluated a low-dose buprenorphine hydrochloride group (n = 16) and an untreated control group (n = 5). All animals were inoculated with Shigella flexneri, strain 2a 2457T, onto the cornea and conjunctiva of each eye. At the onset of clinical signs, analgesics were administered to test groups. The degree of keratoconjunctivitis was evaluated per standard procedure; animals were weighed daily. After 7 days, animals were euthanatized and the eyes were removed for histologic morphometric evaluation.(ABSTRACT TRUNCATED AT 250 WORDS)

Epidemiologic investigation of an outbreak of cutaneous leishmaniasis in a defined geographic focus of transmission.

An outbreak of cutaneous leishmaniasis occurred in a unit of 608 Puerto Rican national guardsmen conducting jungle warfare training in the Panama Canal Area in July 1984. An epidemiologic investigation of reported nonhealing, ulcerating skin lesions was conducted among 540 (89%) unit members in November and December 1984. Fifteen (88%) of 17 individuals with chronic, ulcerating skin lesions were confirmed as cases of cutaneous leishmaniasis by culture or histopathology. Twelve cases yielded positive Leishmania cultures, identified as L. braziliensis panamensis by cellulose acetate electrophoresis. Evaluation of different diagnostic techniques revealed that direct examination of tissues by Giemsa-stained histological examination was the most sensitive test (87% sensitivity), with an indirect immunofluorescent antibody test being rather insensitive (67%). All but one of the confirmed cases operated in small units that trained and slept overnight at a mortar firing site for a period of three days, yielding a site-specific attack rate of 22% (14 of 64). This contrasted with a much lower attack rate of 0.2% (1 of 476), experienced by unit members who trained at other locations during the same time frame (P less than 0.001). The median incubation period calculated from day of arrival at the mortar firing site was 17 days (range 2-78) for the 15 confirmed cases. Available personal protection methods, such as the use of insect repellents, were not appropriately implemented by unit personnel and thus, were not found to effectively protect against Leishmania infection. This is the largest reported outbreak of cutaneous leishmaniasis in military personnel associated with a single geographic focus of infection and contrasts with the usual sporadic disease experience in Panama.

Mortality in Syrian hamsters infected with Paragonimus kellicotti.

In an attempt to find a small animal model for paragonimiasis, Syrian hamsters were infected with between 1 and 16 metacercariae of Paragonimus kellicotti. A definitive mortality dose-response was observed with 90% of all hamsters given 3 or more parasites succumbing to the infection within 35 days. Hamsters demonstrated acute pleuritis, reactive mesothelial hyperplasia, subpleural accumulations of reactive and mature plasma cells, neovascularization, fibrohistiocytic thickening with and without giant cells, raised fibroconnective tissue lesions, and granulomatous inflammation with hemorrhage. Perivascular plasmacytic (lymphocytic) infiltrate, multifocal bronchopneumonia, and parenchymal necrotizing suppurative granulomatous inflammation, hemorrhagic pneumonia, and diffuse sprinkling of eosinophils, neutrophils, and intraalveolar macrophages also were observed. The response observed here may represent a new small animal mortality model useful in the search for new compounds to treat early trematode infections.

Further development of the baboon as a model for acute schistosomiasis.

Baboons develop a syndrome, including eosinophilia and transient fever, after infection with cercariae of Schistosoma mansoni that is consistent with the human syndrome of acute schistosomiasis. Radiotelemetry can be used to follow the course of fever in infected baboons. Individual variations in intensity of disease were noted in baboons. These symptoms and signs were more closely linked to the onset of oviposition by the newly matured worms than they were to the presence of migrating schistosomula or maturing worms. The baboon is concluded to be a suitable and useful model for human acute schistosomiasis mansoni.

The American lung fluke, Paragonimus kellicotti, in a cat model.

Twenty-four specific-pathogen-free domestic cats were infected orally with from 2 to 30 Paragonimus kellicotti metacercariae and followed for 2-61 wk. Following infection by metacercarial cysts dissected from crayfish, the lungs of the cats undergo changes of intense eosinophilic pneumonia, granulomatous pneumonitis, squamous epithelial-lined cyst formation of bronchogenic origin, and finally (late in infection) partial resolution of the host response. Bronchograms and mechanical probing illustrate the patency of cyst communication with bronchi. The modulation of the host response and adaptive changes in the host lung tissue are seen late in infection and have previously been unreported or underemphasized. These adaptive responses may account for the number of asymptomatic cases accidentally found in veterinary patients and the difficulty in prompt and proper diagnosis in human cases.