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The synthesis of four new computer-designed fluoroquinolones which have been predicted by QSAR analysis to be active against the protozoa
Toxoplasma gondii is described. These compounds are ...inhibitory in vitro for
T. gondii. One of these compounds has a remarkably high activity comparable to that of trovafloxacin. It combines the basic cyclopropyl–quinoline structure of gatifloxacin or moxifloxacin with the C-7 6-amino-3-azabicyclo3.1.0hexyl side chain of trovafloxacin. The four compounds are also inhibitory for blood stages of
Plasmodium falciparum though at high concentration. These results confirm the potential of quinolones as
anti-
T. gondii and antimalarial drugs but also show that the QSAR models for
T. gondii cannot be reliably extended for screening antimalarial activity.
Porous silica gels, synthesized via the acid hydrolysis and basic condensation of TMOS, have been used for the encapsulation of antigens. The pores of the matrix are large enough to allow the ...diffusion of antibodies through the gel. Antigen-antibody specific fixation occurs within the sol-gel matrix. It can be detected via the so-called enzyme linked immunosorbent assays (ELISA). Antigen-antibody associations occurring in the gel are optically detected via the reaction of a peroxidase conjugate with ortho-phenylenediamine leading to the formation of a yellow coloration. Immunoassays have been performed using the hydatid cyst fluid as the source of antigens and sera from human patients as the source of antibodies. Specific fixation appears to be as good in the sol-gel matrix as in antigen solutions.
Summary
The authors present marsh rat Holochilus brasiliensis, jirds Meriones shawi and M. unguiculatus as new models of Schistosoma haematobium infection. Histological findings were compared with ...those of classic models mouse Mus and hamster Mesocricetus. In new models, embryonated eggs were seen in the stool from 90 days post infestation (DPI) and active disease developed from 117 to 175 DPI. Seven out of 10 rodents presented granulomatous and/or chronic cystitis, fibrosis, polyps and urothelial changes: squamous metaplasia, precancerous dysplasia and squamous cell carcinoma of the urinary bladder. In the digestive tract of all new models, granulomas eroded the mucosa, formed inflammatory polyps, infiltrated the wall and accumulated into bilharziomas. In the liver, granulomatous hepatitis surrounded by bilharzial pigment deposit was apparent. Pipe‐stem fibrosis involved 4 rodents with precirrhotic changes in 1 and portal hypertension in 2. One female Meriones suffered from granulomatous endometritis and salpingitis. All new models developed pulmonary granulomatosis with associated vascular lesions: giant cell arteritis in 1 rodent, thromboses in 3 and pulmonary hypertension in 4 others. In classic models, 1 Mus presented a squamous cell carcinoma of the urinary bladder while Mesocricetus displayed diverse lesions in digestive and genital tracts, liver and lungs. All tissue lesions, resembling those seen in humans in all points, were far more frequent and severe in new models than in classic ones. Those involving the urinary bladder have never been reported in other models such as monkeys: Pan troglodytes, Cercopithecus aethiops and Cebus apella. A comparison was carried out between different models on the basis of experimental conditions: definitive hosts, number of cercariae used, type and duration of infection. This study clearly demonstrated that Holochilus brasiliensis, Meriones shawi and M. unguiculatus are perfectly adequate models in terms of laboratory facilities. They are helpful in investigating the pathogenic mechanism of some disorders in S. haematobium infection, particularly tumours of the urinary bladder, and this may enhance therapeutic assays.
Porous silica gels, synthesized via the acid hydrolysis and basic condensation of TMOS, have been used for the encapsulation of antigens. The pores of the matrix are large enough to allow the ...diffusion of antibodies through the gel. Antigen-antibody specific fixation occurs within the sol-gel matrix. It can be detected via the so-called enzyme linked immunosorbent assays (ELISA). Antigen-antibody associations occurring in the gel are optically detected via the reaction of a peroxidase conjugate with ortho-phenylenediamine leading to the formation of a yellow coloration. Immunoassays have been performed using the hydatid cyst fluid as the source of antigens and sera from human patients as the source of antibodies. Specific fixation appears to be as good in the sol-gel matrix as in antigen solutions.
The kinetics of skin penetration of Schistosoma haematobium (Bilharz, 1852) (Trematoda, Schistosomatidae) cercariae is reported for the first time, Meriones unguiculatus (Rodent, Gerbillidae) being ...used as experimental model. It has been demonstrated that the cercariae cross the epidermis of their hosts either directly or through hair follicles culs-de-sac from 3 to 5 min. The corresponding schistosomulae slide into the superficial part of the dermis or move along the base of hair follicles. Six minutes after, schistosomulae are found in the lumen of lymphatic vessels running alongside blood capillaries. One hour post-infestation, the dermis presents acute inflammatory reaction with edema, infiltration of neutrophil and eosinophil leukocytes. Conversely, dilated blood capillaries do not contain any schistosomula. Thus, the initial migration path of infective larvae of S. haematobium in M. unguiculatus is lymphatic.
A study was carried out in 1993 in south Cameroon in order to assess the changes in the incidence rate of human paragonimiasis, and to get information on the transmission pattern of Paragonimus sp. ...Two human cases have been recorded, and one dog was found infected in the Ntem Valley. The results suggest that a decrease of the incidence rate of paragonimiasis occurred in humans and animals. Paragonimus metacercariae were found in three species of freshwater crabs: Sudanonautes africanus, S. aubryi et S. granulatus, the latter being a new host. Prevalence of infection in crabs increased southerly, and significant seasonal changes were found. Two cats were infested with metacercariae from S. africanus, and studies are in progress to identify the parasite(s) at a specific level.
En Asie du Sud-Est, il existe une mosaïque de situations épidémiologiques en rapport avec la diversité des espèces de schistosomes rencontrés. Certaines d'entre-elles ont des aires de répartition ...très vastes. Quelques unes sont strictement animales (
Schistosoma sinensium), alors que d'autres sont soit à l'origine de zoonoses (
S. mekongi) soit accidentelles et déterminant chez l'homme une impasse parasitaire (
S. japonicum-like,
S. malayensis, S.
mansoni-like). A l'exception du S.
mansoni-like de Thaïlande, toutes les autres appartiennent au complexe
japonicum dont la particularité est d'avoir subi une évolution concomitante à celle de leurs hôtes intermédiaires, à partir d'un ancêtre commun.
Far East Asia shows a lot of epidemiologic situations in functions of various species of schistosomes seen. Some of them are widespread. Some are only seen in animals (
Schistosoma sinensium), when others are cause of zoonotic infections (
Schistosoma japonicum, S. malayensis, S. mansoni-like). Except for
S. mansoni-like from Thaïlande, all other species belong to the
japonicum complex. Its particularity is to have undergrown a concomitant evolution with its intermediary hosts from a common ancestor.
Les schistosomes d'ammaux d'Asie Farhati, K.; de Pecoulas, Ph. Eldin; Rajguru-Kazemi, M. ...
Médecine et maladies infectieuses,
2/1995, Letnik:
25, Številka:
2
Journal Article
Les schistosomes d'animaux d'Asie du Sud-Est se répartissent principalement dans le complexe
S. indicum (
Schistosoma indicum, S. nasale, S. spindale et
S. incognitum) et accessoirement dans le ...complexe
S. japonicum (
S. sinensium). Certains de ces schistosomes restent localisés en Inde alors que d'autres se trouvent dans tout le sous-continent indien. Leur importance en médecine vétérinaire est variable, allant de la parasitose bien tolérée à la maladie grave ou mortelle aux conséquences économiques considérables.
South-East asian schistosomes in animals mostly belong to the
S. indicum complex (
Schistosoma indicum, S. nasale, S. spindale and
S. incognitum) and also to the
S. japonicum one (
S. sinensium). Some of them can be found only in India, when other have spread every where in the Indian sub-continent. Their veterinary implication is variable; from a well-supported disease to a life threatening one which has some important economical repercussions.
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