Oral infection of mice with trophozoites of Giardia muris.

Giardia muris has been maintained for years in the mouse by administering by gavage 10,000 trophozoites taken from the small intestine of infected mice. Despite the growth of numerous protozoa in the intestine, absorption of tetracycline hydrochloride in infected mice was not changed to a statistically significant extent, as blood drug levels increased only slightly: behavior was similarly unaffected. Reasons for the apparent lack of virulence of this strain are discussed.

[Parasites of the respiratory system: research and significance (author's transl)]. / Parassiti dell'apparato respiratorio: ricerca e significato

A review is made of the methods of diagnosing both autochthonous and exotic protozoal and helminthic diseases of the respiratory system. Referring to protozooses, recent findings on respiratory pathology due to amoebae of the genus Acanthamoeba are commented, and modern methods are discussed of checking for Pneumocystis carinii in the patient, not just on autopsy material. Referring to helminthiases, in addition to pulmonary echinococcosis which is of prevalent interest in Italy, attention is also given to the pathology of migrant larvae of nematodes. Finally, the role of some microscopic mites in the pathogenesis of respiratory allergic disease from house dust is discussed.

[Infection of mice with oral administration of trophozoites of Giardia muris]. / Infezione del topo per via orale con singoli trofozoiti di Giardia muris.

For the last 9 years we have used Giardia muris for chemotherapy research, passing trophozoites scraped from the mouse small intestine into fresh mice, by gavage. More or less every trophozoite administered orally reproduces in the intestine, as shown by quantitative studies in groups of young, specific pathogen-free mice, treated with 1, 3, 10, 30 or 100 Giardia each. After 7-9 days the number of protozoa in the intestine diminished somewhat, in the groups infected with the largest number of trophozoites.

New data on the mechanism and speed of action of nitroimidazoles on prokaryota and eukaryota with and without mitochondria.

The spectrum of action of nitroimidazoles ranges from anaerobic bacteria to aerobic bacteria which are also capable of growth, although sometimes with difficulty, in anaerobic atmosphere and to protozoa without and with mitochondria; in the latter case the anti-protozoal activity depends on the importance of the extramitochondrial enzymes which respond to nitroimidazoles. The more anaerobic the organisms, the greater their sensitivity. In the most sensitive protozoa, the trichomonads, most of the enzymatic reactions inhibited by these drugs take place in the hydrogenosomes; these are cytoplasmatic organelles surrounded by a membrane whose disintegration, in fact, is the first visible effect of the action of the nitroimidazoles. Various nitroimidazoles act with different speed on these and other protozoa, whose membranes can difinitely possess different degrees of permeability towards substances with different chemico-physical characteristics. In the treatment of trichomoniasis, the specific speed of action of a drug is perhaps as important as its half-life in man.

Snythesis and antiprotozoal activity of nitro derivatives of 2, 2'-biimidazole.

We synthesized a series of 2,2'-biimidazoles with different substituents and screened them against Entamoeba histolytica, Trichomonas vaginalis and Giardia muris. A 5-nitro group is necessary for the inclusion of activity and an amino group exercises favourable effect on in vivi activity.