In vitro survival of Echinococcus granulosus protoscolices in several media, at +4 degrees C and +37 degrees C

As a first step towards hydatid disease control, the in vitro survival of protoscolices of Echinococcus granulosus was investigated for various media and temperatures. Higher percentage survival was obtained than previously reported: at 4 degrees C, 100% survival was obtained for 20 days in medium 199 (GIBCO) and for 25 days in hydatid fluid from the host of origin. Maximal survival was 30% at 55 days in these conditions. Flame cell activity was the criterion of choice for viability. At 37 degrees C survival rates were lower and morphological changes in protoscolices were observed.     

Quality of semen stored at +15 degrees/16 degrees C as related to fertility of artificially inseminated swine

Linear correlations between swine semen quality and fertility (birth rate and number live born pigs) were studied. Doses of swine semen with 4 × 10⁹ motile spermatozoa were used after being stored at +15°/16°C. However, mean or high correlations could not be found. Low correlations occurred between head-acrosome anomalies, total anomalies and birth rate. It is likely that the doses of semen with 4 × 10⁹ motile spermatozoa were too concentrated for the fertility level in the swine breed employed.     

Temperature dependence of the microwave properties of aqueous solutions of ethylene glycol between +15 degrees C and -70 degrees C.

The values of the dielectric constant and of the loss tangent for samples of 0 m (distilled H₂O), 1 m, 2 m, 3 m, 4 m, 5 m, 10 m, and 100% ethylene glycol were determined over the temperature range of +15 °C to ?70 °C. An operating frequency of 1.40 GHz to 1.55 GHz was used, allowing the results to be applied directly to both 0.915 GHz and 2.450 GHz studies. Strong temperature and concentration dependencies were found; low concentration solutions tended to behave similarly to water, while higher concentration solutions were more independent. Peak values and discontinuities occurred at different temperatures, depending on concentration. Five molar ethylene glycol was indicated as a near optimum concentration based on toxicity, cryoprotection, and microwave power absorption considerations. A study of blends of cryoprotectants is suggested.     

A follow-up on functional parameters of blood stored in ACD at +4 degrees C

The main functional parameters of blood stored at +4 degrees C in ACD, according to the common transfusional practice, have been carefully followed in the course of 40 days. The expected depletion of DPG takes place within 10 days, but apparently, no increase of the Hb affinity towards oxygen is observed in this period (or later), because pH lowering acts in the opposite direction during the same time. However, the intrinsic increased affinity of Hb is promptly revealed if the "actual" pHs are corrected at the standard value of 7.4, and/or are extrapolated at this pH from Bohr effect.     

Na+ATPase of the mammalian erythrocyte membrane. Reversibility of phosphorylation at 0 degrees.

When human erythrocyte membranes are phosphorylated with a very low concentration of [gamma-32P]ATP (0.02 muM) at 0 degrees, and then EDTA is added, rapid disappearance of the phosphoenzyme intermediate of Na+ATPase is observed. The initial rapid phase of phosphoenzyme disappearance is, for the most part, not associated with P1 release and its rate constant, kD, is severalfold greater than the ratio of Na+ATPase activity to phosphoenzyme intermediate, v:EP, at steady state. It is concluded that this rapid disappearance of phosphoenzyme is due to resynthesis of ATP via reversal of phosphorylation. In contrast, rapid reversal is not observed when excess nonradioactive ATP is added to reduce E32P formation, provided Mg2+ is present; however, K+ added with the ATP stimulates reversal. Rapid reversal following EDTA addition is unlikely also when higher ATP concentrations (greater than or equal to 10(-6) M) are used to phosphorylate the enzyme since, at higher ATP, kD congruent to v:EP. The results are compatible with the concept that the Na+ATPase enzyme is composed of two or more catalytic subunits, in which ATP at one catalytic site can regulate the reactivity at another site.     

Changes in the rheologic properties of various samples of blood preserved at +4 degrees C

Apparent stationary viscosity, viscoelasticity and thixotropy measured with a Couette viscosimeter have been determined on blood samples stored in eight anticoagulant and/or preservative solutions. All the results as well as those obtained in a previous morphological study show clearly the advantages of the SAG or PAGGS storage processes. It is observed that the rheological parameters of RBC stored in protein poor media are, between the 30 th and 35 th days, identical on CPD at the first week and with that measured in CPD concentrates between second and third week (for a same hematocrit value). We want to emphasize that the erythrocytes stored in these new media retain for a long time their ability to circulate in the capillary system.     

Induced immotility during long-term storage at +5 degrees C does not prolong survival of dog spermatozoa

This study investigated whether the immotility induced by the CLONE chilled semen extender prolongs the lifespan of dog spermatozoa stored at 5 degrees C, compared with a Tris-egg yolk-glucose (TG) extender, which maintains motility. Pooled semen was split in four aliquots, centrifuged, and the four sperm pellets mixed with TG extender; with the CLONE chilled semen (CL) extender; with TG extender mixed with an activator (TG+A(TG)); or with the CLONE extender mixed with the CLONE activator (CL+A(CL)). Samples were stored at 5 degrees C for 23 days and examined 12 times for sperm motility, plasma membrane and acrosome integrity, glucose consumption, and DNA fragmentation index (DFI). The experiment was performed in triplicate. Glucose consumption was not significantly different between extenders until the period 15-23 days, when it was higher in CL and CL+A(CL) than in TG (P=0.0055) and TG+A(TG) (P=0.0010). No breakdown of DNA chromatin (P>0.05) occurred until day 14. Spermatozoa preserved in TG or TG+A(TG) showed better values for all the different parameters throughout the experiment compared with sperm subjected to CL or CL+A(CL). In conclusion, the immotility induced by the CLONE chilled semen extender during long-term cold storage at 5 degrees C did not prolong the lifespan of spermatozoa compared with the lifespan following storage in Tris-egg yolk-glucose. In addition, our results indicate that good quality dog semen may possibly be stored for up to 14 days in TG extender at 5 degrees C, with retained fertilizing capacity. In vivo studies should, however, be performed to further support this conclusion.