The production of mammalian trematode infective stages by the snail Galba truncatula

Several experiments on the breeding of trematode-infected Galba truncatula for obtaining and packaging Fasciola hepatica and Paramphistomum daubneyi metacercariae were carried out to determine the more convenient methods to use for commercial production of these infective stages. Compared to the breeding of infected snails in aquaterraria, the use of 14-cm Petri dishes allowed a greater prevalence of snail infection and a higher number of metacercariae. The production of these larvae was still 2.3–3.4 times greater if infected snails were dissected during the patent period. The aspiration of these metacercariae at the extremity of a Pasteur pipette significantly shortens the time necessary for their transfer from Petri dishes to Eppendorf tubes. Using 14-cm Petri dishes, snail dissection and metacercarial aspiration for their transfer strongly reduce the cost price for metacercarial production of the trematodes Fasciola hepatica and Paramphistomum daubneyi.

Experimental infection in Notodiaptomus sp. (Crustacea: Calanoida) with larvae of Camallanus sp. (Nematoda: Camallanidae)

This trial registered the experimental infection viability with nematode larvae Camallanus sp. in Notodiaptomus sp., a crustacean, which can be an intermediate host. Adult females of nematode were dissected from the intestines of Xiphophorus maculatus (Osteichthyes: Poeciliidae), at a fish farm in the State of São Paulo. Females were slightly compressed for larvae release, collected with Pasteur pipette and separated on Petri dishes with 9ml filtered water at 28.1ºC, from zooplankton culture. Treatments consisted of Petri dishes with 60 and 105 copepods, in which 120, 150 and 210 larvae of nematode were added in four replications. Twenty-four and 36h after exposition to the larvae, the copepods were fixed in 70% alcohol to record the amount of fixed larvae. Twenty four hours after exposition, 60 copepods group with 120 larvae showed significantly higher prevalence (46.5%) when compared to 105 copepods and 120 larvae (33.2%). Thus, these answers suggested that 120 larvae were enough for a successful infectivity. Experimental infection was available and so, it was used as a pattern to life cycle studies of camallanid nematodes and hosts susceptibility tests.

Orbital sinus blood sampling in rats as performed by different animal technicians: the influence of technique and expertise

In this study the influence of orbital sinus blood sampling on clinical signs was studied within the framework of various nutritional experiments. In order to assess the clinical signs in a random design, the rats were punctured in either the left or the right orbit. Thus, the effect of puncture within rats could be determined by comparing the left and right eye. Four animal technicians punctured a total of 303 rats, using different techniques. Orbital sinus blood sampling caused clinically visible alterations. The type, frequency and prognosis of the alterations differed with the person performing the puncture. Two experienced animal technicians were able to perform the technique without causing a statistically significant increase in alterations in punctured orbits. One less experienced animal technician caused severe abnormalities. The use of either a Pasteur pipette or a haematocrit capillary did not necessarily produce different results. Neither did puncturing the lateral vs the medial canthus of the orbit. By not applying chloramphenicol eye ointment in the conjunctival sac after puncture, the number of abnormalities in 'ocular discharge' and 'corneal alterations' in the punctured orbits was significantly decreased. Four punctures in the same orbit with 14-day intervals by a skilled animal technician did not cause a significant increase in abnormalities.

Fate mapping the neural plate and the intraembryonic mesoblast in the upper layer of the chicken blastoderm with xenografting and time-lapse videography

The disposition of the Anlage fields of the neural plate and the intraembryonic mesoblast in the upper layer of the chicken blastoderm was studied at the primitive streak stage prior to the regression of Hensen's node (stages 5V to 6V, L. Vakaet (1970) Arch. Biol. 81, 387–426). Chicken blastoderms were cultured by New's technique on a mixture of thin egg white and agar. The anterior half of the deep layer was reflected with a tungsten needle. A circular fragment of the upper layer was punched out with a pulled out Pasteur pipette and discarded. It was replaced with an isotopic and isopolar piece of quail upper layer that was punched out with the same pipette. The deep layer was replaced and the chimeras were reincubated for 24 hours. The xenografts were followed with time-lapse videography. After fixation, the quail cells were located using Le Douarin's quail nucleolar marker technique. Integrating the observations with time-lapse videography and the results of Feulgen stained sections, we have drawn a new fate map of the disposition of the Anlage fields in the upper layer of the chicken blastoderm at stages prior to the regression of Hensen's node (stages 5V to 6V). The disposition of the neural plate and of the notochord, somites, nephrotome and lateral plates was therefore determined before the Anlage fields are morphologically discernible. The pathway of the fields in the upper layer towards their disposition was documented with time-lapse videography in chimeric chicken blastoderms that developed normally.