Biomedical subjects

A Fiorentino

Publications and source records attributed to A Fiorentino.

At least 19 recordsLinked to original sources

PubMed2001

Solid-state photodimerization of cholest-4-en-3-one.

Crystalline cholest-4-en-3-one undergoes solid-state dimerization by UV radiation to give two ring A - ring A connected dimers. No dimerization occurs in solution. The first dimer, characterized by a cyclobutane ring, is formed by connection of C-2 and C-3 of a moiety with C-5' and C-6' of another moiety, respectively. The latter dimer has a six-membered ketal ring formed by connection of C-2 with C-5' and of O, linked to C-3, with C-3'. The structures have been determined by spectroscopic means. X-ray analysis of title compound evidences the proximity of the axial H-2 of a molecule to the C-4' of a molecule in the upper layer. The transfer of the hydrogen and the connection between C-2 and C-5' might be the driving force of dimerization.

Journal Article↗

PubMed2001

Lactone diterpenes from the aquatic plant Potamogeton natans.

Four lactone diterpenes and two related glucosides with a labdane skeleton have been isolated from the aquatic plant Potamogeton natans. The structures of three new compounds were determined as 19-acetoxy-20-oxo-8(17),13-ent-labdadien-15-->16 lactone, 8(17), 13-ent-labdadien-15-->16,19-->20 dilactone and 6'-acetyl-19-glucopyranosyloxy-8(17),13-ent-labdadien-15-->16 lactone, respectively, by means of spectral analysis. Antialgal assays showed inhibitory activity for some compounds.

Diterpenes↗

PubMed2000

Antialgal ent-labdane diterpenes from Ruppia maritima.

Seven ent-labdane diterpenes have been isolated from Ruppia maritima. The structures 15,16-epoxy-ent-labda-8(17),13(16),14-trien-19-al; 15,16-epoxy-ent-labda-8(17),13(16),14-trien-19-ol acetate; methyl 15,16-epoxy-12-oxo-ent-labda-8(17),13(16),14-trien-19-oate; 15,16-epoxy-ent-labd-8(17),13E-dien-15-ol and 13-oxo-15,16-bis-nor-ent-labd-8(17)-ene have been assigned to the five new compounds by spectroscopic means and chemical correlations. The phytotoxicity of the diterpenes has been assessed using the alga Selenastrum capricornutum as organism test.

Diterpenes↗

PubMed2000

Effect of recombinant human gonadotrophins on human, bovine and murine oocyte meiosis, fertilization and embryonic development in vitro.

The response of murine, bovine and human oocytes to pure recombinant preparations of human follicle stimulating hormone (rFSH) and luteinizing hormone (rLH) for meiotic maturation and subsequent developmental competence in vitro were examined in the present experiments. Maturation of immature bovine oocytes to the metaphase II stage was significantly increased by the addition of 1 IU/ml of rFSH in combination with either 1 IU/ml rLH or 10 IU/ml rLH. Similarly, embryonic development to the blastocyst stage was improved in bovine oocytes treated with a 1:10 combination of rFSH:rLH. However, no significant difference was observed in the number of inner cell mass or trophectoderm cells of the resulting blastocysts. Although the increased maturation to metaphase II was not significant, human embryonic developmental competence was improved by maturing oocytes in the presence of a 1:10 ratio of rFSH:rLH as only those oocytes exposed to a 1:10 ratio of rFSH: rLH during maturation showed normal cleavage patterns beyond day 2. In addition, 1 IU/ml rFSH and 1 IU/ml rLH increased the expression of oocyte proteins in human oocytes. The inclusion of recombinant gonadotrophins, either singly or in combination, had no significant effect on the maturation, fertilization or embryonic development of in-vitro matured mouse oocytes. These data provide support for the responsiveness of human and bovine oocytes to gonadotrophins in vitro and the need to consider variations in the relative concentrations for optimization of oocyte developmental competence.

Animals↗

PubMed1999

Pregnancies after activated oocyte transfer: a new option for infertility treatment.

In this preliminary report, we describe a new technique involving the same-day transfer of activated oocytes to the uterus after intracytoplasmatic sperm injection (ICSI). The technique, termed activated oocyte transfer (AOT), offered to 19 couples, yielded a pregnancy rate per cycle of about 30%, equivalent to traditional in-vitro fertilization (IVF) and ICSI in a laboratory setting. AOT is performed 4 h after oocyte retrieval, permitting the patient to undergo treatment as an out-patient procedure.

Adult↗

PubMed1998

Modification of the Talairach stereotactic system for CT-compatibility: technical note.

A modification of the Talairach stereotactic system is described which is able to incorporate CT data and provides both co-ordinate calculations, directly from the CT console screen and by a fiducial reference system. The device maintains the original base plate, thus allowing its interfacing with all the accessories of the early apparatus and its direct use in the stereotactic operating room. The instrument has shown great reliability in the localisation of brain lesions and considerable flexibility in many stereotactic operations such as biopsy procedures, brachytherapy, radiosurgery and stereotactically assisted resections.

Equipment Design↗

PubMed1997

Preimplantation genetic diagnosis increases the implantation rate in human in vitro fertilization by avoiding the transfer of chromosomally abnormal embryos.

OBJECTIVE: To verify the percentage of chromosomally abnormal preimplantation embryos in patients with a poor prognosis and possibly to increase the chance of implantation by selecting chromosomally normal embryos. DESIGN: A prospective, randomized, controlled study. SETTING: In vitro fertilization program at the Reproductive Medicine Unit of the Società Italiana Studi Medicina della Riproduzione, Bologna, Italy. PATIENT(S): In a total of 28 stimulated cycles, the maternal age was > or = 38 years and/or the patient had > or = 3 previous IVF failures, factors that indicated a poor prognosis. After consent, 11 patients underwent preimplantation genetic diagnosis for aneuploidy, whereas 17 controls underwent assisted zona hatching. INTERVENTION(S): Simultaneous analysis of chromosomes X, Y, 13, 18, and 21 in a blastomere biopsied from day-3 embryos. Chromosomal analysis was performed with fluorescence in situ hybridization. Assisted zona hatching was performed on day-3 embryos from the control-group patients. MAIN OUTCOME MEASURE(S): Embryo morphology, results of fluorescence in situ hybridization, clinical pregnancies, and implantation. RESULT(S): In the study group, a total of 61 embryos were analyzed by fluorescence in situ hybridization, and 55% were chromosomally abnormal. Embryo transfer with at least one normal embryo was performed in 10 cycles. Four clinical pregnancies resulted, with a 28.0% implantation rate. In the control group, 41 embryos were transferred in 17 cycles after the assisted zona hatching procedure, yielding four clinical pregnancies and an 11.9% implantation rate. CONCLUSION(S): Infertile patients classified as having a poor prognosis have a high percentage of chromosomally abnormal embryos. The advantage of selecting and transferring embryos with normal fluorescence in situ hybridization results has an immediate impact on implantation.

Adult↗

PubMed1997

Will preimplantation genetic diagnosis assist patients with a poor prognosis to achieve pregnancy?

PGD (preimplantation genetic diagnosis) of aneuploidy for chromosomes X, Y, 13, 18 and 21 was carried out on 196 embryos from 36 infertile patients classified with a poor prognosis due to (i) maternal age, (ii) repeated in-vitro fertilization (IVF) failures and (iii) mosaic karyotype. The percentage of abnormal embryos was comparable in the three groups of patients: maternal age 63%, repeated IVF failure 57%, and mosaic karyotype 62%. The analysis of the overall data revealed an increased incidence of abnormal embryos in the older age categories (predominantly due to aneuploidy), even in embryos at the 7- to 8-cell stage. In addition, the percentage of chromosomally abnormal embryos was directly proportional to the number of IVF failures, where the increase in chromosomal abnormalities was not correlated to aneuploidy but to other aberrations such as mosaicism and polyploidy. Following PGD, 28 patients had at least one embryo transferred that appeared normal by fluorescent in-situ hybridization (FISH). Four clinical pregnancies resulted, with an implantation rate of 10% per normal embryo. In conclusion, the high rate of chromosomally abnormal embryos in poor prognosis patients may have been the cause of implantation failure in their previous IVF cycles. Therefore, the possibility of transferring embryos with a normal FISH complement could improve the chance of pregnancy in this category of patients.

Adult↗

PubMed1996

Reducing the time of sperm-oocyte interaction in human in-vitro fertilization improves the implantation rate.

Human oocyte development was evaluated after a reduced time exposure to spermatozoa in vitro. A total of 119 patients were assigned to two study groups in a randomized prospective study in which each patient's oocytes were exposed to spermatozoa for either 1 h (group 1 - 58 patients) or the standard 16 h incubation period (group 2 - 61 patients). The fertilization rate obtained in group 1 was higher than in group 2 (285/393, 73%, and 272/410, 66% respectively), suggesting that the spermatozoa-oocyte interaction occurs within 1 h. This was confirmed in a study in vitro using fluorescently labelled spermatozoa and normal oocyte-cumulus complexes. Spermatozoa enter the cumulus complex within 15 min, traverse the cumulus layer within 3 h, and first appear in the oocyte cortex at 4 h post-insemination. The incidence of polyspermy was higher in oocytes exposed to spermatozoa for 16 h (3%) than for 1 h (1%). There was no difference in the cleavage rate or morphological characteristics of embryos from both study groups. However, when evaluating the timing of embryo development, group 1 generated a significantly higher percentage of four to five cell embryos when compared to group 2 (55 versus 39%; P < 0.001), documented at 40 h post-insemination. The implantation and pregnancy rates for group 1 were 11 and 28%, while the corresponding rates for group 2 were 8 and 15%. This suggests that a reduced exposure of oocyte to spermatozoa favours embryo viability, possibly due to a decrease in potential damage from sperm metabolic waste products.

Adult↗

PubMed1996

Prolonged sperm-oocyte exposure and high sperm concentration affect human embryo viability and pregnancy rate.

A reduced time interval of oocyte exposure to spermatozoa was investigated to assess whether it could enhance oocyte development and improve embryo viability, especially in cases of male factor infertility. A total of 167 patients were included in a prospective randomized study. They were randomly allocated to two major study groups, A (n = 85) and B (control group; n = 82). The oocytes from group A patients were exposed to spermatozoa for only 1 h; those from group B were exposed for 16 h. The two study groups were then subdivided according to semen quality for further analysis of the results. Significantly higher percentages were obtained in group A than in group B in terms of the fertilization rate (74 versus 68%, P < 0.025), cleavage rate (53 versus 41%, P < 0.005), pregnancy rate (27 versus 12%, P < 0.05) and implantation rate (11 versus 6%, P < 0.05). In addition, an increased fertilization rate was achieved in oocytes exposed to male factor spermatozoa for only 1 h compared with the conventional incubation period (78 versus 65%, P < 0.01). Advanced cellular stages (55 versus 41%, P < 0.02) and higher implantation rates (13 versus 4%, P < 0.05) were attained in the subgroup whose oocytes were exposed to normal spermatozoa for 1 h compared with the male factor spermatozoa with the standard culture interval. The higher fertilization rates, enhanced embryo development and viability achieved in group A indicate that prolonged exposure of oocytes to high concentrations of spermatozoa is detrimental, decreasing sperm-oocyte interaction and subsequent embryo implantation, particularly in male factor patients.

Adult↗

PubMed1996

Improved cleavage rate of human embryos cultured in antibiotic-free medium.

Retarded development and blastomere fragmentation of human preimplantation embryos represent a common phenomenon in in-vitro culture systems. Even though media composition is generally formulated to meet embryo nutritional requirements, the influence of antibiotic supplementation has not been investigated thoroughly. The present study was performed to evaluate the effects of antibiotics on embryo morphology and growth in modified culture media. A total of 196 zygotes from 18 couples was cultured in three different media: (i) conventional medium (n = 99, control group); (ii) medium modified with half the standard antibiotic concentration (n = 54; and (iii) antibiotic-free medium (n = 43); 49 embryos from the control group were selected at the zygote stage and transferred to the patients on day 2. The remaining 147 zygotes were cultured to the blastocyst stage for cryopreservation; their morphology and cell number were assessed daily at 40, 64, 88 and 112 h post-insemination. Overall cleavage rate was 95% and embryo scoring revealed 91% grade 1 embryos throughout the culture period in the three media. Significantly higher cleavage rates were obtained in the antibiotic-free medium at each observation, including the blastocyst stage, when compared to the other two groups. In addition, no notable improvement was observed in the embryos cultured in a reduced concentration of antibiotics. In conclusion, antibiotic supplementation of media has an adverse effect on the growth rate of preimplantation embryos, even in reduced concentrations, suggesting that antimicrobial drugs may interfere with the timing of cleavage events either by delaying or blocking embryo development.

Adult↗

PubMed1994

Sperm:oocyte ratios in an in vitro fertilization (IVF) program.

PURPOSE: During the past few years, many oocyte insemination techniques, including microinjection, have evolved in the treatment of male-factor infertility. This preliminary study was designed to evaluate whether microdroplet insemination could be considered a reliable technique, especially for semen samples with male-factor defects. The first objective was to assess fertilization rates obtained by inseminating sibling oocytes using both the conventional IVF and the microdroplet method (Group 1). The second objective was to evaluate subsequent embryo development and pregnancy rates resulting from microdroplet insemination, in addition to formulating adequate sperm:oocyte ratios for various semen categories (Group 2). Four semen categories were studied including fresh normal sperm, frozen/thawed normal sperm, and male-factor sperm with one defect and two or three defects. RESULTS: Group 1 consisted of 54 couples; no statistical significance was found in the fertilization rates between test tube and microdroplet insemination in all four semen categories. Based on these results, patients from Group 2 (48 couples) had their oocytes inseminated only in microdroplets with sperm:oocyte ratios ranging from 2000 to 10,000 motile sperm:1 oocyte. The average fertilization rate for male-factor sperm was 55%, with a 91% cleavage rate. CONCLUSION: Higher fertilization rates were observed in the lowest range of sperm:oocyte ratios (2000-4000:1) for male-factor sperm with one defect and in the highest range (8000-10,000:1) for male-factor sperm with two or three defects. Polyspermy occurred in only 0.4% of the oocytes inseminated. Microdroplet insemination is an alternative treatment for moderate to moderately severe male-factor infertility, establishing a bridge between conventional IVF and microinjection. With adequate sperm:oocyte ratios, this technique allows the natural selection process of fertilization in vitro to take place, without the high incidence of polyspermy or mechanical damage frequently observed in assisted fertilization techniques.

Adult↗

PubMed1994

Cycloartane glucosides from Juncus effusus.

Five new cycloartane glucosides, juncosides I-V, have been isolated from Juncus effusus. The structures have been determined on the basis of chemical and spectroscopic studies.

Carbohydrate Sequence↗

PubMed1994

Oleanane glycosides from Hydrocotyle ranunculoides.

Six new oleanane glycosides, ranuncosides I-VI, have been isolated from Hydrocotyle ranunculoides. Their structures have been determined on the basis of chemical and spectroscopic studies.

Carbohydrate Sequence↗

PubMed1994

Progesterone bioconversion by microalgal cultures.

Ten different strains of unicellular microalgae have been used in the bioconversion of progesterone. Regio and stereoselective reduction and hydroxylation of the title compound were induced. A 9,10-seco derivative was obtained in high yield by using Scenedesmus quadricauda.

Biotransformation↗

PubMed1994

Biological factors affecting subzonal sperm microinjection results.

One hundred and sixteen couples with severe male factor infertility underwent 139 subzonal sperm microinjection cycles. In total, 1343 oocytes were microinjected, resulting in a fertilization rate of 24%, followed by a cleavage rate of 65%. In 26% of the zygotes, fertilization was delayed and embryos derived from these zygotes demonstrated a poor capacity for further growth and implantation. In 102 of 139 cycles (73%) embryo transfer was performed, resulting in 9 pregnancies. This study followed the fate of injected oocytes and early embryo development to investigate biological factors that influence the results of subzonal injection.

Embryo Transfer↗

PubMed1990

Can iodine-131 whole-body scan be replaced by thyroglobulin measurement in the post-surgical follow-up of differentiated thyroid carcinoma?

This study compared serum thyroglobulin measurement and whole-body scans in the post-surgical follow-up of patients with differentiated thyroid carcinoma. Thyroglobulin levels were measured in 61 patients receiving L-thyroxine therapy after thyroidectomy, and again after suspension of therapy, before performing a whole-body scan with iodine-131. The sensitivity, specificity, and accuracy of thyroglobulin levels, measured during L-thyroxine therapy, for diagnosis of tumor residue or metastases were then calculated and compared with results obtained by diagnostic whole-body scanning. Our data show that neither thyroglobulin levels nor whole-body scans alone can discriminate between patients with or without metastases. Sensitivity reached 95.7%, specificity 100%, and accuracy 96.7% if results of both procedures were also taken into consideration. We conclude that in the management and follow-up of patients with differentiated thyroid carcinoma both parameters need to be evaluated.

Adenocarcinoma↗

PubMed1989

Postoperative recurrence of simple goiter and replacement therapy. Study of 210 patients.

The incidence of recurrent goiter after different surgical procedures for colloid-cystic goiter has been studied in 210 patients. The results of the study confirm the high incidence of recurrence (35.7%). This incidence was shown to be higher in patients undergoing more conservative surgery. Furthermore, the incidence resulted also higher in younger patients, while it was lower after postoperative replacement therapy.

Adolescent↗