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C Galeazzi

Publications and source records attributed to C Galeazzi.

10 recordsLinked to original sources
PubMed2004

Antisperm antibodies modify plasma membrane functional integrity and inhibit osmosensitive calcium influx in human sperm.

BACKGROUND: The hypo-osmotic swelling (HOS) test evaluates the ability of the functional sperm plasma membrane to stretch following cell swelling when exposed to hypo-osmotic solutions. Sperm samples with low HOS scores show low fertilization and pregnancy rates during assisted reproductive techniques, though data are controversial. The aim of this study was to compare the results of the HOS test in a group of normozoospermic men with those in a group of subjects affected by autoimmune infertility due to the presence of antisperm antibodies (ASA) bound to the sperm surface. METHODS: Sperm from normozoospermic and from infertile subjects affected by autoimmune infertility were exposed to hypo-osmolar conditions to verify the effects on intracellular calcium concentrations and acrosome reaction. RESULTS: Sperm samples from infertile men with ASA showed HOS test scores that were significantly lower than those of normozoospermic subjects despite similar sperm viability percentages. Sperm with ASA bound to their plasma membrane showed a reduced rise in intracellular calcium concentrations and acrosome reaction after hypo-osmotic challenge with respect to sperm from normozoospermic subjects without ASA. CONCLUSIONS: Infertile subjects with ASA have a reduced sperm plasma membrane functional integrity that could explain, at least in part, the low fertilization and pregnancy rates observed in these subjects during assisted reproductive procedures. Evaluation for the presence of ASA in all sperm samples showing low HOS test scores in the presence of normal sperm viability percentages is suggested.

Acrosome Reaction↗
PubMed2001

Intracellular calcium store depletion and acrosome reaction in human spermatozoa: role of calcium and plasma membrane potential.

We evaluated the presence and role of internal calcium stores in human uncapacitated spermatozoa by determining the effects of two inhibitors of Ca2+ ATPase of the sarco-endoplasmic reticulum (SERCA-ATPase), thapsigargin and cyclopiazonic acid (CPA) on intracellular calcium concentrations, [Ca2+](i), plasma membrane potential and acrosome reaction. Using a fluorescent conjugate of thapsigargin, we localized internal Ca2+ stores on the acrosome, post-acrosomal region and sperm midpiece. SERCA-ATPase inhibitors induced a rise in [Ca2+](i) both in Ca2+ and Ca2+-free media but under these latter conditions it was reduced with a progressive decline to baseline values; the re-addition of Ca2+-stimulated a rise in [Ca2+](i). This demonstrated that internal Ca2+ store depletion can evoke the opening of Ca2+-channels on sperm plasma membrane, thus showing the existence of "capacitative" Ca2+ entry into these specialized cells. The addition of thapsigargin to human spematozoa induced a dose-dependent increase in acrosome reaction percentages, but only when Ca2+ was present in the external medium. Plasma membrane potential monitoring showed that these inhibitors induced a depolarization dependent on Ca2+ influx from external medium and that this was preceded by a transient hyperpolarization caused by activation of Ca2+-dependent K+ channels. When K+-dependent plasma membrane hyperpolarization was inhibited, the thapsigargin- and CPA-stimulated rise in [Ca2+](i) plasma membrane depolarization and acrosome reaction were abolished. In conclusion, the present study demonstrates that human spermatozoa possess internal Ca2+ stores and that the capacitative Ca2+ entry pathway present in these cells regulates important biological processes that are fundamental for the acrosome reaction.

Acrosome Reaction↗
PubMed1999

Sperm treatment with extracellular ATP increases fertilization rates in in-vitro fertilization for male factor infertility.

Previous work from our laboratory has revealed that extracellular ATP is a rapid and potent activator of human sperm acrosome reaction and fertilizing ability. In the present study, we assessed the effects of in-vitro sperm incubation with ATP on fertilization and embryo development in couples undergoing in-vitro fertilization (IVF) for male factor infertility. Oocytes from 22 women undergoing ovulation induction were divided in two groups and inseminated in vitro either with selected spermatozoa from the corresponding partner suffering from male factor infertility pre-incubated with ATP (2.5 mM) for 1 h, or with spermatozoa incubated with 0.9% NaCl solution (control group). After insemination, fertilization was assessed by the presence of pronuclei and then by embryo cleavage. The fertilization rate in the group of oocytes inseminated with ATP-treated spermatozoa improved significantly with respect to the control group (65.7 versus 42.5%, P < 0.01). No significant differences were observed in embryo cleavage and embryo quality. Embryos from both treated and control groups were transferred together in 20 transfer procedures, and in two couples fertilization was not obtained. Nine pregnancies occurred: one biochemical, one miscarriage, and seven patients delivered 9 healthy babies. Two pregnancies were twin with an overall pregnancy rate of 40.9% per cycle and of 45% per transfer. In conclusion, the results of the present study demonstrate that, in humans, extracellular ATP induces a significant increase of sperm fertilizing potential, as these findings are a rationale for the use of ATP for in-vitro treatment of human spermatozoa during IVF.

Adenosine Triphosphate↗
PubMed1999

Analysis of meiosis in intratesticular germ cells from subjects affected by classic Klinefelter's syndrome.

Azoospermic subjects affected by Klinefelter's syndrome may occasionally show the presence of intratesticular residual foci of spermatogenesis, and the retrieval of mature spermatozoa from the testis may permit fertility and paternity by means of intracytoplasmic sperm injection. Previous studies have demonstrated that these subjects show the presence of an increased incidence of hyperaploid spermatozoa. Here we analyzed, by fluorescence in situ hybridization using specific probes for chromosomes 8, X, and Y, the spermatogenic process and the meiotic progression of 47,XXY germ cells retrieved by fine needle aspiration of the testis in ten azoospermic patients affected by classic Klinefelter's syndrome. All patients had lower testicular volume, higher gonadotropins, and lower testosterone plasma levels compared with control subjects. Cytological analysis of the testicular cells retrieved by fine needle aspiration showed the presence of Sertoli cells only in eight subjects, while germ cells were observed in two patients. In each patient Sertoli cells showed a 47,XXY karyotype, and the same chromosome pattern was observed in spermatogonia and primary spermatocytes of patients presenting a residual spermatogenesis. Secondary spermatocytes, spermatids, and mature spermatozoa showed different sex chromosome patterns, reflecting their origin from 47,XXY spermatogonia. In conclusion, this study demonstrated that, in subjects affected by Klinefelter's syndrome, residual germ cells may be present in the testis and that 47,XXY spermatogonia are able to undergo and complete the spermatogenic process leading to mature spermatozoa. These data further suggest the need to evaluate the sex chromosome status of sperm from patients affected by Klinefelter's syndrome undergoing assisted reproductive techniques.

Adult↗
PubMed1998

High incidence of sperm sex chromosomes aneuploidies in two patients with Klinefelter's syndrome.

In this study we have investigated the arrangement of sex chromosomes in sperm from two severe oligozoospermic patients, apparently affected by the classic form of Klinefelter's syndrome (KS). Multicolor fluorescence in situ hybridization has been used to recognize chromosomes X, Y, and 8 in sperm from patients and 10 fertile men with normal 46,XY karyotype. In patients affected by KS, we detected important numerical sex chromosome abnormalities (approximately 20%). In all normal fertile men, X- and Y-bearing spermatozoa were present in a 1:1 ratio. On the contrary, in our patients the frequency of 23,Y-bearing sperm was strongly reduced compared with that of both 23,Y sperm in the controls and 23,X sperm in the same subject affected by KS, resulting in a 23,X-/23,Y-bearing sperm ratio of 2:1. Moreover, the frequency of 24,XY disomic sperm was significantly higher in the absence of the 22,0 hypoaploidy expected from a common origin from a nondysjunction during the first meiosis in a normal 46,XY cell. In conclusion, the results of the present study demonstrate a peculiar distribution of sex chromosomes in sperm from two patients with KS, in agreement with the hypothesis that 47,XXY germ cells are able to complete the meiotic process by producing mature spermatozoa.

Adult↗
PubMed1995

Functional and structural characteristics of human epididymal spermatozoa retrieved by transcutaneous aspiration.

The present paper describes the development of a simple, repeatable technique for transcutaneous aspiration of epididymal spermatozoa in patients with inoperable excretory azoospermia. Some functional and structural parameters of the retrieved spermatozoa were also evaluated. Epididymal spermatozoa from patients and ejaculated spermatozoa from fertile donors showed similar percentages of acrosome-reacted cells after incubation for 6 or 15 h in capacitating medium. Penetration of zona-free hamster oocytes, expressed as the percentage of penetrated ova, was significantly lower (p < 0.01) for spermatozoa from patients than for ejaculated spermatozoa from fertile donors. The percentage of epididymal spermatozoa with stable nuclei in sodium dodecyl sulphate was lower (p < 0.001) than for ejaculated spermatozoa from fertile donors. A positive linear correlation (r = 0.74, p < 0.005) was evident between the oocyte penetration rate and the percentage of spermatozoa with stable nuclei. In conclusion the percutaneous retrieval of epididymal spermatozoa in excretory azoospermia allows collection of motile spermatozoa, which can be evaluated for their structural and functional characteristics before repetition of the technique for retrieval of spermatozoa for assisted fertilization techniques.

Adult↗
PubMedDate not supplied

[Analysis of sperm aneuploidy in infertile subjects after chemotherapy treatment].

The continuing search for a cure for cancer has developed more aggressive therapies that may damage germ cells, leading to clinical disease in offspring of survivors. Standard therapy for the majority of cancer today consists in combinations of high doses of radiation and chemotherapy drugs. We investigated the effect of cancer treatments on the reproductive potential of men. Multicolor fluorescence in situ hybridization has been used to recognize chromosomes X, Y and 8 in sperm of 10 severely oligozoospermic subjects (sperm concentration < 5,000,000/mL) treated for cancer at least 5 years before the beginning of this study. As controls, we analyzed sperm aneuploidies in 20 fertile men (sperm concentration > 20,000,000/mL) and in 20 severe idiopathic oligozoospermic subjects (sperm concentration < 5,000,000/mL). In all subjects, X- and Y-bearing spermatozoa were present in a normal 1:1 ratio; nevertheless the frequency of 24,XY, 24,XX and 24,YY disomic sperm was significantly higher in patients treated for cancer and in idiopathic oligozoospermic subjects with respect to normozoospermic men. These results suggest that the increase in sperm aneuploidies in treated patients cannot be reported directly to precedent chemotherapy, but reflects the alteration of testicular structure, as in the case of severe idiopathic oligozoospermic subjects. With the advent of intra-cytoplasmic sperm injection, it is possible to offer the opportunity to conceive in men affected by severe oligozoospermia but it is also possible, when the spermatozoa of these subjects are used, to pass sex chromosome abnormalities on to the children. We therefore suggest caution before application of an artificial reproductive technique in severe oligozoospermic patients.

Analysis of Variance↗