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Biomedical subjects

A Cesana

Publications and source records attributed to A Cesana.

12 recordsLinked to original sources
PubMed2005

Cryopreservation of supernumerary oocytes in IVF/ICSI cycles.

BACKGROUND: The aim of the present study is to investigate cryopreservation of oocytes in patients refusing embryo cryopreservation for ethical reasons, patients from whom no sperm could be retrieved and patients with enough oocytes to yield a number of fresh and cryopreserved embryos to transfer. METHODS: A total of 2900 oocytes out of 6216 retrieved were cryopreserved in 286 patients undergoing 303 cycles. The reasons for cryopreservation were because no sperm was found in 16 cycles, for ethical or personal reasons in 80, and in 207 only supernumerary oocytes were frozen. In 159 cycles, the oocytes were thawed and the surviving metaphase II oocytes microinjected. RESULTS: A total of 1087 oocytes were thawed, 760 (69.9%) survived and 687 were microinjected. We obtained 368 (53.5%) normally cleaved embryos, 331 were transferred and 37 were cryopreserved. One hundred and forty-five transfers (range 1-3 embryos/patient) were performed and 18 (12.4%) pregnancies were obtained. Twelve patients delivered 13 healthy children, and six first trimester abortions were observed (33.3%). CONCLUSION: Although a low implantation rate was observed and a higher abortion rate than in fresh cycles, our results show that in sibling oocytes, the process of cryopreservation apparently does not affect the fertilization and cleavage rate. In this group of patients, producing a large number of mature gametes, oocyte cryopreservation gives the couple extra chances to achieve a pregnancy within a single retrieval and is a good effort towards reducing the number of embryos cryopreserved and enhancing our experience in this new technology.

Adult↗
PubMed2005

Outcome of assisted reproductive technologies after different embryo transfer strategies.

The outcomes of 1028 assisted reproductive technology cycles were studied retrospectively, considering two different periods of embryo transfer. In the first period, 262 cycles in women < 36 years old were studied, in which three embryos were transferred, followed by 157 cycles in women > or = 36 years, in which four embryos were transferred. In the second period, 332 cycles were evaluated in women < 36 years and 277 cycles in women > or = 36 years old, reducing the number of embryos transferred to two and three respectively. Embryos were only scored morphologically, and the best embryos were chosen for transfer. In the first period, in women < 36 years old, a clinical pregnancy rate of 55.7% was achieved, compared with 42.5% in the second period (P < 0.01). In women > or = 36 years old, the first period of embryo transfer showed a clinical pregnancy rate of 39.5%, compared with 28.5% in the second period (P < 0.01). The number of twin pregnancies in the three groups of patients in whom one to four embryos were transferred was not significantly different (24.2, 28.4, 24.8%). It is concluded that even with the biases induced by a retrospective study, the reduction in the number of embryos transferred, from three to two in women < 36 years of age, and from four to three in women > or = 36 years of age, without any selection other than pre-transfer morphological score, adversely affects the outcome of treatment, without a significant reduction in twin gestation rate. Other strategies are to be implemented in gametes and embryo selection, and patients must be aware that, even with a reduction in pregnancy rate, the goal is to achieve a high cumulative pregnancy rate, reducing the complications induced by multiple pregnancies.

Adult↗
PubMed2005

Secondary photon fields produced in accelerator-based sources for neutron generation.

Neutrons can be produced with low-energy ion accelerators for many applications, such as the characterisation of neutron detectors, the irradiation of biological samples and the study of the radiation damage in electronic devices. Moreover, accelerator-based neutron sources are under development for boron neutron capture therapy (BNCT). Thin targets are used for generating monoenergetic neutrons, while thick targets are usually employed for producing more intense neutron fields. The associated photon field produced by the target nuclei may have a strong influence on the application under study. For instance, these photons can play a fundamental role in the design of an accelerator-based neutron source for BNCT. This work focuses on the measurement of the photon field associated with neutrons that are produced by 4.0-6.8 MeV protons striking both a thin 7LiF target (for generating monoenergetic neutrons) and a thick beryllium target. In both cases, very intense photon fields are generated with energy distribution extending up to several MeV.

Beryllium↗
PubMed2005

A very low-background gamma-ray counting facility in the Baradello underground laboratory.

An underground station for the measurement of low-level radioactivity is in operation in Northern Italy in the town of Como under the Baradello hill. The rock cover is -300 m water equivalent. This paper reports about the preliminary measurements carried out to characterise the site of the Baradello hill and the installation of a high-purity Ge detector with a radio-pure copper shielding. Features and levels of the achieved background are reported and discussed, in comparison with other above ground and underground low-radioactivity stations. Sensitivities to radioactivity in typical environmental matrices are evaluated, confirming the very low-gamma background attained in the laboratory.

Air Pollutants, Radioactive↗
PubMed2004

Characterization of an underground site in Northern Italy in view of low radioactivity measurements.

A low background station for the measurement of low level radioactivity is under development in Northern Italy. The rock cover is about 300 m water equivalent. We report and discuss measurements of radon concentration in air and of gamma, muon and neutron fluxes performed in the neighborhood of the station site. We present and apply a simple analytical model capable to disentangle the contribution to the measured gamma activities due to 222Rn in air from the one due to 238U and its daughters in the rocks.

Environmental Monitoring↗
PubMed1975

[Hodgkin's disease in the malignant lymphoma category atypical clinical aspects].

Various clinical and pathological features of Hodgkin's disease and its related disorders are discussed: a rare, benign form of Hodgkin's disease with skin loci only; unusual primary sites (bone, spleen, lungs and intestine---including alphs-chain disease): various paraneplastic syndromes caused by hyperparathyroidism and hypercorticism; idiopathic nephrotic syndromes of immunological origin. Reference is also made to possible relationships between lymphoma and leukaemia.

Bone Neoplasms↗