A comparison of techniques for studying oogenesis in the European eel Anguilla anguilla.

A multi-technique approach was used to study the changes occurring in European eel Anguilla anguilla ovaries during hormonally-induced vitellogenesis. Aside from classic techniques used to monitor the vitellogenic process, such as ovary histology, fat content analysis, sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and vitellogenin enzyme linked immunosorbent assay (ELISA), a new technique, Fourier-transform infrared (FT-IR) microspectroscopy, was used to analyse A. anguilla ovaries. The results from the different techniques provided different ways of approaching the same process. Although it is considered a time consuming approach, of all the employed techniques, histology provided the most direct evidences about vitellogenesis. SDS-PAGE and ELISA were also useful for studying vitellogenesis, whereas fat analysis cannot be used for this purpose. The FT-IR analysis provided a representative IR spectrum for each ovarian stage (previtellogenic stage, early vitellogenic stage, mid-vitellogenic stage and late vitellogenic stage), demonstrating that it is a valid method able to illustrate the distribution of the oocytes within the ovary slices. The chemical maps obtained confirmed changes in lipid concentrations and revealed their distribution within the oocytes at different maturational stages. When the results and the accuracy of the FT-IR analysis were compared with those of the traditional techniques commonly used to establish the vitellogenic stage, it became evident that FT-IR is a useful and reliable tool, with many advantages, including the fact that it requires little biological material, the costs involved are low, analysis times are short and last but not least, the fact that it offers the possibility of simultaneously analysing various biocomponents of the same oocyte.

Subpopulation pattern of eel spermatozoa is affected by post-activation time, hormonal treatment and the thermal regimen.

There has been a marked reduction in natural stocks of eels (genus Anguilla) over the past 60 years, and the culture of eels is still based on the capture of very large quantities of juveniles. It is necessary to close the life cycle in captivity in order to ease the pressure on wild populations. The aims of the present study were to evaluate sperm subpopulations (through cluster analysis of computer-aided sperm analysis data) in the European eel (Anguilla anguilla) and to assess the effects of motility acquisition time after activation (i.e. at 30, 60 and 90s), the thermal regimen (i.e. 10°C (T10) or 15°C (T15) and up to 20°C, or constant at 20°C (T20)) and hormonal treatments (i.e. human chorionic gonadotropin (hCG), recombinant (r) hCG or pregnant mare serum gonadotropin (PMSG)) on these subpopulations. In all cases, we obtained three subpopulations of spermatozoa: low velocity and linear (S1); high velocity with low linearity (S2); and high velocity and linear (S3; considered high quality). Total motility and S1 were affected by acquisition time; thus, 30s is recommended as the standard time for motility acquisition. When eels were kept at 20°C (T20), motility data fitted quadratic models, with the highest motility and proportion of S3 between Weeks 8 and 12 after the first injection. Lower temperatures (T10, T15) delayed spermiation and the obtaining of high-quality spermatozoa (S3), but did not seem to alter the spermiation process (similar subpopulation pattern). Conversely, the hormonal treatments altered both the dynamics of the subpopulation pattern and the onset of spermiation (with PMSG delaying it). Total motility and the yield of S3 with the widely used hCG treatment varied throughout the spermiation period. However, using rhCG allowed us to obtain high-quality and constant motility for most of the study (Weeks 7-20), and the S3 yield was also higher overall (61.8±1.3%; mean ± s.e.m.) and more stable over time than the other hormonal treatments (averaging 53.0±1.4%). Using T20 and rhCG would be more economical and practical, allowing us to obtain a higher number of S3 spermatozoa over an extended time.

Relationship between sperm quality parameters and the fatty acid composition of the muscle, liver and testis of European eel.

This study looks at the correlations that fatty acids have with different tissues in the European eel (Anguilla anguilla L.) during hormonally-induced sexual maturation, with different sperm quality parameters. In order to evaluate the different dynamics of the use of fatty acids, a categorization of the results from each sperm quality parameter (volume, concentration, motility and velocity) was performed. Low and moderate correlations were observed between muscle tissue and some sperm quality parameters but no high correlations were found. Eicosapentaenoic acid (20:5n3, EPA) in the liver seems to have a role in determining the volume of sperm produced. This can be explained by the fact that EPA is a major requirement in the early phases of sperm production (probably as a component of the spermatozoal membrane). In addition, the levels of α-linolenic acid (18:3-n3, ALA) and linoleic acid (18:2-n6, LA) in the liver decreased when sperm motility increased. In all the tissues, a negative correlation was observed between arachidonic acid (20:4n-6, ARA) and the different sperm velocity parameters. The fact that an increase in the consumption of ARA coincides with an increase in the speed of spermatozoa, highlights the important role that this fatty acid plays not only in sperm production, but also in sperm velocity. All this information could prove useful in the development of suitable broodstock diets to improve sperm quality and subsequently, the larval development of this species.

Standardization of European eel (Anguilla anguilla) sperm motility evaluation by CASA software.

The development of powerful computer-assisted sperm analysis software has made kinetic studies of spermatozoa possible. This system has been used and validated for several species, but some technical questions have emerged regarding fish sample evaluations (i.e., frame rate, sperm dilution, chamber model, time of analysis, magnification lens, etc.). In the present study, we have evaluated the effects of different procedural and biological settings with the aim to correctly measure sperm quality parameters of the European eel. The use of different chambers did not affect the sperm motility parameters. However, regarding lens magnification, 10× was the most accurate lens, showing the least variation in the acquired data. Similarly, the frame rate setting resulted in a dramatic effect in some sperm kinetic parameters, primarily in terms of curvilinear velocity; we therefore recommend using the camera's highest available frame rate setting. Finally, the reduction in sperm motility over postactivation times suggests that sperm analysis should be performed within the first 60 seconds after activation of the European eel sperm. In conclusion, some protocol variables of sperm analysis by computer-assisted sperm analysis software can affect the measurement of eel sperm quality parameters, and should be considered before directly comparing results obtained by different laboratories. Moreover, because marine fish species show relatively similar features of sperm kinetic parameters, these results could be considered in the evaluation of the motility of sperm from other fish species.

[Volumetric pumps for blood transfusions. Viability in pediatrics]. / Bombas volumétricas para transfusiones sanguíneas. Viabilidad en pediatría.

UNLABELLED: The authors determine whether or not nurses should use perfusion pumps for concentrated hematin transfusions, measuring the degree of hemolysis which occurs in two distinct models. STUDY SAMPLE: Concentrated hematin transfusions by means of an infusion pump on children in a Pediatrics Intensive Care Unit at the Maternity-Pediatrics Ward in Granada. Dependent Variable: Degree of Hemolysis, measured by means of: free hemoglobin, potassium, LDH. INDEPENDENT VARIABLES: Pump; dated/used blood; hematocrit; catheter caliber; type of procedure; pump working pressure; other perfusion rhythms; infusion rhythm. Sample size. One year study group, 95% confidence rate, 0.50 prevalence of awaited hemolysis, +/- 0.05 precision (relative precision 10%). Data Obtained: Two samples are taken per transfusion: removal of blood bag, extreme distal removal system. Investigative Method: Prospective descriptive study. STATISTICAL ANALYSIS: Descriptive statistics, by means of frequency distributions. Variable analysis, multiple variable analysis. RESULTS: 55 observations were carried, of these, 50.9% corresponded to pump number one. Simple regression linear analysis showed differences in the degree of hemolysis in terms of free hemoglobin and hematocrit. Dated/used blood registered a higher hemolysis level above 75 percentile. The greater hemolysis in terms of potassium difference was associated with the type of procedure, having an average of 0.44 mEq/l, in presence of other perfusions, greater rhythm (p = 0.118), dated/used blood (p = 0.008), hematocrit (p = 0.063). The greatest difference in LDH occurred with smaller caliber catheters, other perfusions, more dated blood (p = 0.117). In multiple linear regression, results were equal to those predicted: an average difference in hemoglobin of 3.87 mg/l (p = 0.661); in potassium, 0.39 mEq/l (p = 0.138); in LDH, 53.6 (p = 0.568). This documents with verify this study have been consulted by the ROL Editorial Board and may be requested from the authors.