Human oocyte cryopreservation: new perspectives regarding oocyte survival.

The success of human oocyte cryopreservation depends on morphological and biophysical factors that could influence oocyte survival after thawing. Various attempts to cryopreserve human oocytes have been performed with contrasting results. Therefore the effect of some factors, such as the presence or absence of the cumulus oophorus, the sucrose concentration in the freezing solution and the exposure time to cryoprotectants, on human oocyte survival after thawing were investigated. The oocytes were cryopreserved in 1,2-propanediol added with sucrose, using a slow-freezing-rapid-thawing programme. After thawing, the oocytes were inseminated by intracytoplasmic sperm injection (ICSI) and the outcomes of insemination and subsequent embryo development were also recorded. The post-thaw cryosurvival rate was not different for the oocytes cryopreserved with their cumuli partially removed mechanically (56%) when compared with those cryopreserved with their cumuli totally removed enzymatically (53%). On the contrary, a significantly higher survival rate was obtained when the oocytes were cryopreserved in the presence of a doubled sucrose concentration (0.2 mol/l) in the freezing solution and the survival rate was even higher when the sucrose concentration was tripled (0.3 mol/l) (60 versus 82% P < 0.001). Furthermore, a longer exposure time (from 10.5 to 15 min) to cryoprotectants, before lowering the temperature, significantly increased the oocyte survival rate (P < 0.005). Intracytoplasmic sperm injection produced a good fertilization rate (57%) of thawed oocytes and a high embryo cleavage rate (91%) and a satisfactory embryo morphology was observed (14 and 34% for grade I and grade II embryos respectively).

Technical aspects of oocyte cryopreservation.

Since the successful development in the mouse, the oocyte cryopreservation has been applied with varying success to a number of different species including the human. The recently reported successes in terms of pregnancies obtained by human oocyte cryopreservation are encouraging. Several studies typically reported different rates of survival (20-80%), fertilization (30-60%) and cleavage (32-100%). This variability of results throws some doubts on the usefulness of oocyte cryopreservation in IVF treatment cycles. It remains to be determined whether the relatively different success rates reported in literature, mainly in terms of survival rate, are due to methodological differences. We tried to investigate the effect of some factors on the oocyte survival rate after thawing: the presence or absence of cumulus oophorus and the exposure time of the oocytes to cryoprotectant. We suggest that a combination of several factors including both morphological and biophisical ones can affect the oocyte survival rate.

Analysis of inheritance of growth trajectories in laboratory populations of guppy-fish.

We analysed the variation of growth trajectories for body length from 40 to 90 days of age in three laboratory populations of Poecilia reticulata. The populations used were two lines of guppy-fish obtained by artificial selection for increased and decreased body length at 70 days and one line maintained under free-breeding condition. The factor analysis performed on the phenotypic correlation matrices among age-specific values of body length showed that a very large portion of the phenotypic variation is confined to a single factor. This factor corresponds to a simultaneous increase/decrease at all ages, hence representing the variation in the height of the growth trajectories. A smaller portion of the variation describes an increase/decrease at early ages followed by the reverse in the later ages, which corresponds to the variation in the shape of the trajectories. The genetic analysis performed on the height and shape of the growth curves showed a additive genetic component for the height in the free-breeding population and for the shape in the selected lines.

Parental age effects on body size and growth rate in guppy-fish.

We analysed the effect of parental ageing on variations in body size and growth rate of guppy-fish progeny. The resulting data showed that the mean body length of the progeny increases with advancing parental age and this increase might be due to a faster growth rate of progeny from older parents. Given the high correlation linking parental age and maternal size, the involvement of size cannot be ruled out, even though parental age had a greater effect than maternal size on the body length of progeny in one of the two populations considered. Variation in progeny growth rate in relation to variation in parental age might be due to an adaptive mechanism which allows the offspring of older parents to reach reproductive age faster.

Ag-NOR protein distribution correlates with patient survival in stage I endometrial adenocarcinoma.

The relationship between argyrophil nucleolar organizer region (Ag-NOR) protein quantity and prognosis was studied in 33 cases of stage I endometrial adenocarcinoma. Ag-NOR protein quantity was measured by image analysis in silver-stained sections from paraffin-embedded samples of curettings. Patients had a minimum 10-year follow-up. Only 2 out of 25 patients exhibiting a mean Ag-NOR protein area of less than 3 microns2 died of cancer, whereas 5 of the 8 patients with a mean Ag-NOR protein area of more than 3 microns2 died of the disease. The present results demonstrate that the Ag-NOR protein value is closely related to patient survival in stage I endometrial carcinoma and that it is a reliable prognostic indicator in this type of carcinoma.

Body weight and growth rate in laboratory lines ofPoecilia reticulata reared on two different diets.

Body weight and growth rate of fish from three laboratory lines fed with two different diets have been analyzed. The differences in response to the diets seem to be related to the different degree of genetic homogeneity of the lines considered. The most homogeneous line shows the greatest variation under the two diets for average body weight at 30 and 70 days as well as for growth rate. An effect of the parents' diet on their offspring was also observed. The increase in growth rate observed when fish are fed with the live food diet is amplified when the progenies derive from parents fed with the dry food diet. Moreover, an effect due to the mother's size is also evident on the mean values of body weight at 30 days. The persistence of this maternal effect on the offspring phenotype during post-embryonic development seems to depend on the degree of genetic homogeneity of the line considered-being the greatest in the most homogeneous line.

[Urinary hydroxyproline in advanced breast carcinoma and response to treatment with medroxyprogesterone acetate (MAP) in high doses]. / Idrossiprolina urinaria nel carcinoma mammario avanzato e risposta al trattamento con medrossiprogesterone acetato (MAP) ad alte dosi.

The Authors have studied total urinary hydroxyproline (TUH), together with other hematochemical analyses, in 104 patients suffering from advanced breast cancer with or without bone metastases. TUH escretion is higher in patients with osseous lesions and, if simultaneous pathologic values of TUH and serum alcaline phosphatase occur, the presence of bone metastases is statistically even more probable. Moreover TUH seems to vary in accordance with the clinical response of the disease at osseous level in 46 patients treated with Medroxyprogesterone acetate (MPA) at high doses, showing itself as a possible marker of not negligible clinical value.

A multivariate analysis of dominance inDrosophila.

Eleven wing measurements in twoDrosophila melanogaster lines (Canton and FLL) and their reciprocal crosses were analyzed by a multivariate technique in order to investigate changes in variability when dominance is manifested. FLL line was obtained by artificial selection for short wing applied on one measurement on the rightwing. Differences between left and right wing were observed in variabilities after selection. The comparison between F1 and parental populations shows that there is strong evidence for non-additivity which is manifested by a component of the variability due to multiple regression. This is interpreted as meaning that relationships between characters are affected in the heterozygote in a non-additive way, apparently due to interactions among the developmental patterns of the characters considered. It is suggested that a "character" should be defined in such a way as to include its developmental patterns, in order to achieve a better understanding of the dominance phenomenon.

Interaction between artificial and natural selection.

In order to understand how divergence may appear within a gene pool without limitations on gene flow, experiments were performed to investigate whether the genetic structure of a population may be effective in controlling the response to natural selection. Starting from plateaued populations of Drosophila melanogaster selected for wing length on the two sexes separately, the response to natural selection was studied after artificial selection had been discontinued. The results show that populations derived from artificial selection applied to the different sexes respond to subsequent natural selection in dissimilar ways, so as to suggest that the relationships between fitness and wing length have been changed. A second experiment comparing the response to natural and to artificial reversed selection suggests that different genes or gene complexes may be involved in wing length determination: these different genes show a dissimilar response in the different sexes and to natural and artificial selection. This variety of responses suggests that the interactions of different genes or gene complexes with artificial and natural selection could possibly lead to differentiation within the population.

Quantitative inheritance and divergence inDrosophila populations.

Divergent sub-populations were obtained following relaxation of artificial selection for short wing in a population ofDrosophila melanogaster. Different results were obtained by relaxing the selection pressure in lines resulting from different selection procedures. The divergence was actually observed between lines derived by reciprocal crosses between vestigial and wild-type heterozygotes belonging to the same selection line. There was a difference in phenotypic variability in the two sub-lines from the start, which might be responsible for the differential response to natural selection. No difference in reproductive fitness has been detected between the divergent lines. The results can not be easily understood in the framework of an additive polygenic model; it is suggested that some complex interaction may be involved, acting on the developmental processes. It seems, however, safe to suggest that the divergence observed is determined by factors which are present in the FM line.

The relationship between fitness and response to selection in Drosophila melanogaster.

The relationship between the selection response exhibited by a morphological trait and the correlated response observed on fitness values has been investigated to improve our understanding of micro-and macro-evolutionary processes. The research was designed to test the validity of the "homeostatic" and "metric deviation" models (Robertson 1956). The results show that: 1) correlated changes in fertility values are larger when selection for minus-variant wing length is applied to males than when it is performed on females, 2) within each of the selected lines, M, F and MF, the reproductive fitness of the populations obtained from vg/vg x +/vg crosses differs from that of the populations derived from +/vg X vg/vg crosses, 3) reproductive fitness values of populations derived from vg/vg X +/vg crosses are fairly constant in selected lines obtained by means of different selective procedures, while mean wing length changes; the corresponding populations from +/vg X vg/vg crosses show, on the contrary, a proportionality between fitness and selected trait values. The lack of consistency of these results with the currently accepted hypotheses on the relationship between selection response and correlated changes in fitness leads to the conclusion that the two models considered do not satisfactorily interpret our results; these are better explained by a developmental relationship between fitness and selected trait.