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R Fabbri

Publications and source records attributed to R Fabbri.

At least 19 recordsLinked to original sources
PubMed2004

Flavor decomposition of the sea-quark helicity distributions in the nucleon from semiinclusive deep inelastic scattering.

Double-spin asymmetries of semiinclusive cross sections for the production of identified pions and kaons have been measured in deep inelastic scattering of polarized positrons on a polarized deuterium target. Five helicity distributions including those for three sea quark flavors were extracted from these data together with reanalyzed previous data for identified pions from a hydrogen target. These distributions are consistent with zero for all three sea flavors. A recently predicted flavor asymmetry in the polarization of the light quark sea appears to be disfavored by the data.

Journal Article↗
PubMed2003

Evidence for quark-hadron duality in the proton spin asymmetry A1.

Spin-dependent lepton-nucleon scattering data have been used to investigate the validity of the concept of quark-hadron duality for the spin asymmetry A1. Longitudinally polarized positrons were scattered off a longitudinally polarized hydrogen target for values of Q2 between 1.2 and 12 GeV2 and values of W2 between 1 and 4 GeV2. The average double-spin asymmetry in the nucleon resonance region is found to agree with that measured in deep-inelastic scattering at the same values of the Bjorken scaling variable x. This finding implies that the description of A1 in terms of quark degrees of freedom is valid also in the nucleon resonance region for values of Q2 above 1.6 GeV2.

Journal Article↗
PubMed2003

Q2 dependence of nuclear transparency for exclusive rho0 production.

Exclusive coherent and incoherent electroproduction of the rho(0) meson from 1H and 14N targets has been studied at the HERMES experiment as a function of coherence length (l(c)), corresponding to the lifetime of hadronic fluctuations of the virtual photon, and squared four-momentum of the virtual photon (-Q2). The ratio of 14N to 1H cross sections per nucleon, called nuclear transparency, was found to increase (decrease) with increasing l(c) for coherent (incoherent) rho(0) electroproduction. For fixed l(c), a rise of nuclear transparency with Q2 is observed for both coherent and incoherent rho(0) production, which is in agreement with theoretical calculations of color transparency.

Journal Article↗
PubMed2003

Ovarian tissue banking and fertility preservation in cancer patients: histological and immunohistochemical evaluation.

OBJECTIVE: A combination of chemotherapy and radiotherapy in young females with cancer has greatly enhanced the life expectancy of these patients, even if these treatments have a highly deleterious effect on the ovary and cause a severe depletion of the follicular store. Cryopreservation of ovarian tissue before chemotherapy and/or radiotherapy, followed by autograft after remission or in in vitro maturation, could restore gonadal function and fertility. The aim of this study is to verify the efficiency of the ovarian tissue cryopreservation procedure by histological and immunohistochemical analyses. METHODS: Ovarian tissue was obtained by laparoscopy from 22 patients affected with different malignant diseases. Tissue specimens were frozen using a combination of PROH (1,2-propanediol) and sucrose as cryoprotectants, and the cryopreservation protocol used consisted of a slow freezing-rapid thawing program. Both fresh and frozen/thawed tissues were embedded in paraffin blocks for histological and immunohistochemical analyses. RESULTS: Good stromal and follicular morphology was found in fresh and frozen/thawed tissue. No significant differences were found in follicular density, distribution, and diameters in fresh and frozen/thawed tissue. Follicle immunohistochemical analysis showed a high percentage of negative staining for both estrogen receptor (ER) (100% both in fresh and frozen/thawed specimens) and progesterone receptor (PR) (97% versus 91%, respectively). Regarding the Ki67 protein, positive staining was found in both the granulosa cells and/or the oocytes (36% in fresh and 56% in frozen/thawed). For the Bcl2 protein, positive staining was observed in the follicle granulosa cells but not in the oocytes in 74% of the fresh and in 79% of the frozen/thawed specimens. For the stromal cells, ER showed a negative staining distribution in 97% of the fresh and 100% of the frozen/thawed specimens. The stroma staining distribution was diffuse/focal in fresh versus frozen/thawed specimens (50% versus 74% respectively) for PR, patch/focal (70% versus 80%, respectively) for Ki67 protein, and diffuse (55% versus 54%, respectively) for Bcl2. CONCLUSIONS: These results suggest that human ovarian tissue morphology, antigenicity, cellular proliferation, and anti-apoptotic index were well preserved by cryopreservation in PROH and sucrose.

Adult↗
PubMed2001

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).

Adult↗
PubMed2000

Clinical experience and applications of oocyte cryopreservation.

Oocyte cryopreservation is a viable solution for the ethical problems related to embryo storage, and the only available technique for preservation of fertility in women who have to undergo chemo- or radiotherapy. The main problems with oocyte cryopreservation are concerned with the survival rate and the fertilization rate. Recently the introduction of the intracytoplasmic sperm injection (ICSI) led to an increase in the fertilization rate. The success achieved with the first case treated encouraged us to set up a clinical trial on human oocyte cryopreservation. In the first stage of the study, 23 women with tubal infertility were enrolled. Superovulation was induced and 375 oocytes were retrieved; of these 338 oocytes were frozen. The survival rate was 59.5% and was independant of the duration of cryopreservation or the presence of cumulus. The normal fertilization rate was 64.4%, and only 7.5% of fertilizations were abnormal. A total of 90.8% of fertilized oocytes cleaved. A mean of 3.1+/-1.3 embryos per patient were transferred. Three pregnancies were achieved. In the second stage of our investigation, more patients were enrolled and similar results were observed. Sixteen pregnancies were achieved. A further stage of the investigation involved the fertilization of frozen oocytes with frozen sperm and even these resulted in a pregnancy. Our study demonstrated that pregnancies can also be achieved when frozen eggs are fertilized by testicular and epididymal sperm. As a consequence of the success of our investigations, a program of oocyte cryopreservation for oncological patients has been initiated in our centre. In our opinion, oocyte cryopreservation is, at present, a safe and efficient technique as documented by the birth of several healthy children.

Cryopreservation↗
PubMed2000

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.

Animals↗
PubMed2000

Micromanipulation of cryopreserved embryos and cryopreservation of micromanipulated embryos in PGD.

The possibility to employ cryopreservation in Preimplantation Genetic Diagnosis (PGD) should enlarge the opportunities for research and clinical activity. For these purposes, we tried three kinds of approaches on human abnormal embryos: (1) cryopreservation of biopsied embryos; (2) biopsy of thawed embryos; and (3) biopsy of embryos derived from thawed oocytes. Our preliminary results show that: (1) biopsy of thawed embryos is feasible and FISH analysis is possible on both survived and lysed cells; (2) Optimization of freezing/thawing procedures are necessary to obtain better survival rate after thawing of biopsied embryos; (3) Biopsy and FISH are feasible on embryos derived from thawed oocytes and they could be a good way to study the chromosomal arrangement of these poorly investigated embryos.

Biopsy↗
PubMed2000

Critical evaluation of an intercalibration exercise undertaken in the framework of the MED POL biomonitoring program.

The results of an intercalibration exercise among the laboratories participating in the MED POL program for monitoring biological effects of pollutants along the Mediterranean coasts are presented. Three established biomarkers, i.e. lysosomal membrane stability, metallothionein concentration and ethoxyresorufin-O-deethylase (EROD) activity, were intercalibrated. The stability of lysosomal membranes in mussels (Mytilus galloprovincialis Lam.) was assessed with a cytochemical method. The four participating laboratories were able to discriminate between control animals (membrane labilization times ranging from 21 to 35 min) and Cu-exposed animals (40 micrograms/l Cu for 3 days) (labilization times ranging from 4.5 to 7.4 min). The metallothionein concentration was evaluated in digestive gland homogenates of control mussels and of animals exposed to 200 micrograms/l Cd for 7 days. The eight participating laboratories were able to discriminate between controls and treated samples using a spectrophotometric method. The EROD activity was evaluated by 11 laboratories. All laboratories were able to discriminate between liver microsomal preparations obtained from control and from benzo-a-pyrene exposed fish (Dicentrarchus labrax), with values ranging from 0.5 to 15.88 pmol/min/mg protein in controls and from 5.41 to 165.13 pmol/min/mg protein in treated animals. Using S9 fractions, it was possible to correctly identify control and treated fish, with a variation similar to that found using microsomal fractions, albeit with an inevitable difference in specific activity. As a corollary, all laboratories involved produced comparable data and were able to identify pollutant-induced stress syndromes in sentinel organisms. Thus, intercalibration enables the use of biomarkers in large biomonitoring programs.

Animals↗
PubMed2000

Human embryo development and pregnancies in an homologous granulosa cell coculture system.

PURPOSE: Our purpose was to determine the effects of the coculture of embryos on human granulosa cells (GCs) in patients in the first cycle of IVF-ET treatment and in patients with repeated implantation failures and to investigate the presence of specific proteins in a 48-hr GC conditioned medium and the GC ultrastructural characteristics. METHODS: Eighteen patients with tubal or idiopathic infertility were enrolled in this study: 7 patients (Trial 1) were in the first cycle of IVF-ET treatment and 11 patients (Trial 2) had repeated implantation failures (one to five). Embryos from each patient were cocultured randomly either on homologous granulosa cells or on a conventional culture medium. RESULTS: At the end of the coculture period (day 5 or 6), 50% of the embryos (Trial 1) reached the blastocyst stage, with respect to 35% in Trial 2. The pregnancy rate per retrieval was 14.2 and 9%, respectively, in Trial 1 and in Trial 2. Many conditioned media showed proteins of 24-29 kDa. and some of them showed additional proteins of 90 kDa. The ultrastructural analysis of GCs showed healthy, metabolically active, protein-synthesizing, and mostly steroidogenic cells. CONCLUSIONS: GC cultures improve embryo development but not pregnancy rates both in Trial 1 and in Trial 2.

Adult↗
PubMed1999

Ongoing pregnancy after intracytoplasmic injection of testicular spermatozoa into cryopreserved human oocytes.

Human oocyte cryopreservation has met with limited success in terms of both survival and subsequent fertilization. We recently reported the first birth of a healthy female infant after intracytoplasmic sperm injection of cryopreserved oocytes. The current report describes the first pregnancy achieved after intracytoplasmic injection of testicular sperm into cryopreserved human oocytes.

Adult↗
PubMed1999

Genotoxicity biomarkers in the assessment of heavy metal effects in mussels: experimental studies.

Heavy metals are stable and persistent environmental contaminants. The range of metal concentrations is generally below acute thresholds in coastal areas, where recognition of chronic sublethal effects is more relevant. Evidence of long-term adverse effects, such as cancer, due to heavy metals in marine animals comes from a number of field and experimental studies. The mechanism of metal carcinogenicity remains largely unknown, although several lines of experimental evidence suggest that a genotoxic effect may be involved. The aim of our study was to evaluate the sensitivity of genotoxicity tests, alkaline elution and micronucleus test, as biomarkers for the detection of heavy metals in mussels as the sentinel species. Experimental studies were carried out on Mytilus galloprovincialis exposed in aquarium (5 days) to different concentrations of three selected metal salts, CuCl2 (5, 10, 20, 40, 80 micrograms/l/a), CdCl2 (1.84, 18.4, 184 micrograms/l/a), and HgCl2 (32 micrograms/l/a), and to a mixture of equimolar doses of the three metals to study the results of their joint action. Metallothionein quantitation was used as a marker of metal exposure. Lysosomal membrane stability was applied to evaluate the influence of physiological status on genotoxic damage. The ranking of genotoxic potential was in decreasing order: Hg > Cu > Cd. Cu and Hg caused an increase of DNA single-strand breaks and micronuclei frequency. Cd induced a statistical increase of DNA damage, but gave negative results with the micronucleus test. A relationship between genotoxic effects and metallothionein content was observed. Reduction in lysosomal membrane stability with the increasing concentration of heavy metals was also evident.

Animals↗
PubMed1998

Follicular fluid and human granulosa cell cultures: influence on sperm kinetic parameters, hyperactivation, and acrosome reaction.

OBJECTIVE: To evaluate the influence of human granulosa cell (GC) cultures and follicular fluid (FF) on sperm kinetic parameters, hyperactivation, and the acrosome reaction compared with the influence of human tubal fluid (HTF) and Ham's F-10 medium. DESIGN: Sperm kinetic parameters, hyperactivation, and the acrosome reaction were evaluated after 6 hours of incubation in HTF, Ham's F-10 medium, FF, and GC cultures. SETTING: Infertility and In Vitro Fertilization Centre, Reproductive Endocrinology Unit, Institute of Obstetrics and Gynaecology. PATIENT(S): Sixteen normal semen samples. INTERVENTION(S): Sperm kinetic parameters and hyperactivation were analyzed using an automated videomicrography system, the acrosome reaction was performed using a triple-stain technique, and progesterone and 17OH-progesterone levels were measured with the use of commercially available kits. MAIN OUTCOME MEASURE(S): Sperm kinetic parameters, hyperactivation, acrosome reaction. RESULT(S): The percentage of motile sperm, the mean curvilinear velocity, and the mean of the maximum amplitude of lateral head movement were increased significantly after 6 hours of incubation in FF or GC cultures compared with incubation in HTF or Ham's F-10 medium, whereas the mean linearity was decreased significantly. Follicular fluid and GC cultures significantly increased hyperactivation and the acrosome reaction compared with the values obtained using HTF and Ham's F-10 medium. Progesterone and 17OH-progesterone levels were increased significantly after incubation in FF and GC cultures compared with HTF and Ham's F-10 medium. CONCLUSION(S): Follicular fluid and GC cultures increase sperm motility parameters, hyperactivation, and the acrosome reaction. This effect may be related to GC detoxification of the microenvironement or GC secretion of peptides, glycoproteins, growth factors (insulin-like growth factors 1 and 2), or steroids (progesterone and 17OH-progesterone).

17-alpha-Hydroxyprogesterone↗
PubMed1998

Oocyte cryopreservation.

Cryopreservation of human oocytes has been employed with little success in clinical practice, even though it may solve the legal and ethical problems linked to embryo freezing. Various attempts to cryopreserve human oocytes have mostly been unsuccessful, leading to low oocyte survival rates after thawing, and the search for an optimal protocol for oocyte cryopreservation remains elusive. A preliminary study was undertaken to evaluate some of the factors influencing the survival rate of human oocytes and the efficiency of intracytoplasmic sperm injection (ICSI) as an insemination procedure. A total of 38 women with tubal infertility were enrolled in the study. The cryopreservation procedure consisted of a slow freeze-rapid thawing technique using 1,2 propanediol and sucrose as cryoprotectants. The overall oocyte survival rate was approximately 60%. A better survival rate was obtained when the oocytes were cryopreserved in the presence of partially removed cumulus oophorus rather than in the presence of totally enzymatically removed cumulus oophorus. The cryoprotectant concentration and the equilibration time also appear to influence the oocyte survival rate. ICSI may be an efficient method of achieving a satisfactory outcome in terms of fertilization in cryopreserved human oocytes. Embryonic morphological quality does not seem to be compromised by cryopreservation. In conclusion, these data show that cryopreservation may ensure that the integrity of the human oocyte is adequate for normal fertilization and embryo development.

Adult↗
PubMed1997

Birth of a healthy female after intracytoplasmic sperm injection of cryopreserved human oocytes.

OBJECTIVE: To describe the first birth achieved after intracytoplasmic sperm injection (ICSI) of cryopreserved human oocytes. DESIGN: Case report. SETTING: University of Bologna Hospital, Department of Obstetrics and Gynecology, Reproductive Endocrinology Unit, IVF and Infertility Center. PATIENT(S): One patient undergoing IVF. INTERVENTION(S): Transvaginal ultrasound-guided oocyte retrieval followed by oocyte freezing. Artificial preparation of the endometrium with E2 and P, oocyte thawing, and ICSI. RESULT(S): Four of 12 cryopreserved oocytes survived; using ICSI, 2 underwent normal fertilization but only 1 cleaved. One good-quality 4-cell embryo was transferred. A single gestation was confirmed by ultrasound at the 7th week. Amniocentesis was performed at the 16th week and demonstrated a normal female karyotype of 46,XX. After a normal pregnancy, a healthy female infant was born at the 38th week of gestation. CONCLUSION(S): The combination of ICSI and oocyte cryopreservation is a new tool in assisted reproductive technology.

Adult↗
PubMed1997

Chronobiologic evolution of luteinizing hormone secretion in adolescence: developmental patterns and speculations on the onset of the polycystic ovary syndrome.

OBJECTIVE: To investigate the long-term evolution of the LH circadian profile in adolescent women with anovulatory cycles and normal or elevated LH levels in the first evaluation. DESIGN: Prospective controlled clinical study. SETTING: Reproductive endocrinology unit of an academic medical center. PATIENT(S): Twelve healthy anovulatory adolescent girls aged 12 to 17 years (5 subjects with high plasma LH level and 7 subjects with normal LH level) and four ovulatory subjects as controls. INTERVENTION(S): Blood samples were drawn every 20 minutes for 24 hours beginning at 10:00 A.M. at early and late gynecologic ages. MAIN OUTCOME MEASURE(S): Luteinizing hormone, FSH, E2, T, androstenedione, ovarian volume. RESULT(S): In the first evaluation, the highest plasma LH levels and greatest pulse amplitude were found early in the morning in the normal-LH group and late in the afternoon in the high-LH group. Controls did not display any significant circadian variation in LH secretion. The second evaluation revealed ovulatory cycles in six of seven subjects (85.7%) in the normal-LH group with the disappearance of the circadian rhythm. Two of five (40%) patients with high LH in the first evaluation became ovulatory with a significant decrease of mean LH levels and the disappearance of the circadian rhythm. Girls of both groups who remained anovulatory still displayed the accentuated circadian profiles that were seen at the first evaluation. CONCLUSION(S): An accentuated 24-hour LH periodicity is typical of puberty but disappears in adulthood. The persistence of these rhythms in persistently anovulatory adolescents may indicate a maturational arrest. In particular, the persistence of the high LH circadian profile with the highest values during the day is very similar to that found in polycystic ovary syndrome.

Adolescent↗
PubMed1997

Births after transcervical gamete intrafallopian transfer with a falloposcopic delivery system.

OBJECTIVE: To evaluate the safety and efficiency of a new delivery system to perform transcervical GIFT. DESIGN: Evaluation of pregnancy rate (PR), miscarriage rate, ectopic pregnancy rate, and delivery rate. SETTING: Institute of Obstetrics and Gynecology, Reproductive Endocrinology Unit, Infertility and IVF Center. PATIENT(S): Twenty-five patients with patent tubes documented by laparoscopy plus falloposcopy. INTERVENTION(S): Superovulation was induced with GnRH analogue and FSH. Under laparoscopic control, transcervical cannulation of the tube was done using a linear everting catheter incorporating direct falloposcopic vision of the tubal lumen. Two lengths of everting catheter (3 and 6 cm) were used providing either isthmic-ampullary or midampullary placement of the inoculum. A comparison was done in terms of ease of access and transfer, falloposcopic observations, and PRs between the groups. MAIN OUTCOME MEASURE(S): Efficacy was established by evaluating the PR, miscarriage rate, ectopic pregnancy rate, and delivery rate. RESULT(S): The PR was 28% (with no differences between the lengths of everting catheters). No ectopic pregnancies occurred. The abortion rate was 28.6% and the delivery rate was 20%. Neither tubal perforation nor other complications occurred during the procedure. CONCLUSION(S): Falloposcopic GIFT is safe and efficient and may be a less invasive alternative than laparoscopic transfer.

Abortion, Spontaneous↗