Alberto Barros

University of Porto, Oporto, Porto, Portugal

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Publications (128)427.91 Total impact

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    ABSTRACT: Summary Asthenozoospermia has been related to structural defects of the sperm flagellum. However, few reports have studied in detail the ultrastructure of sperm with total immotility. We present an ultrastructural study of sperm from five patients with total sperm immotility, four due to dysplasia of the fibrous sheath (DFS) and one with situs-inversus. Of the four patients with DFS, three cases presented a hypertrophic and hyperplastic fibrous sheath that invaded the midpiece space, absence of the annulus, and a short midpiece containing a few disorganized and pale mitochondria. Of these cases, two presented absence of the central complex and radial spokes; another additionally presented absence of dynein arms and nexin bridges; and the other patient presented an intact annulus with a dysplastic fibrous sheath restricted to the principal piece with disorganized microtubule doublets. The patient with situs-inversus presented severe respiratory symptoms, with absence of dynein arms and nexin bridges. In conclusion, we present three cases with DFS associated with total sperm immotility, abnormal mitochondria, and absence of the annulus, central pair complex and radial spokes, of which one had in addition absence of dynein arms and nexin bridges. We also describe a patient, with total sperm immotility and a different presentation of DFS, as the annulus was present and the dysplastic fibrous sheath was restricted to the principal piece. These findings thus confirm the heterogeneity of the DFS condition. The changes observed in the patient with situs-inversus also further support previous observations.
    Zygote (Cambridge, England). 01/2015;
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    ABSTRACT: Caffeine is a widely consumed substance present in several beverages. There is an increasing consumption of energetic drinks, rich in caffeine, among young individuals in reproductive age. Caffeine has been described as a modulator of cellular metabolism. Hence, we hypothesized that it alters human Sertoli cells (hSCs) metabolism and oxidative profile, which are essential for spermatogenesis. For that purpose, hSCs were cultured in with increasing doses of caffeine (5, 50, 500 μM). Caffeine at the lowest concentrations (5 and 50 μM) stimulated lactate production, but only hSCs exposed to 50 μM showed increased expression of glucose transporters (GLUTs). At the highest concentration (500 μM), caffeine stimulated LDH activity to sustain lactate production. Notably, the antioxidant capacity of hSCs decreased in a dose-dependent manner and SCs exposed to 500 μM caffeine presented a pro-oxidant potential, with a concurrent increase of protein oxidative damage. Hence, moderate consumption of caffeine appears to be safe to male reproductive health since it stimulates lactate production by SCs, which can promote germ cells survival. Nevertheless, caution should be taken by heavy consumers of energetic beverages and food supplemented with caffeine to avoid deleterious effects in hSCs functioning and thus, abnormal spermatogenesis. Copyright © 2014. Published by Elsevier Ireland Ltd.
    Toxicology 12/2014; · 3.75 Impact Factor
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    ABSTRACT: To evaluate the impact of WT1 mutations in isolated severe spermatogenic impairment in a population of European ancestry. WT1 was first identified as the gene responsible for Wilms' Tumor and later has been associated with a plethora of clinical phenotypes often accompanied by urogenital defects and male infertility. The recent finding of WT1 missense mutations in Chinese azoospermic males without major gonadal malformations has broadened the phenotypic spectrum of WT1 defects and motivated this study. We have analyzed the WT1 coding region in a cohort of Portuguese non-obstructive azoospermic (NOA; n=194) and severe oligozoospermic (n=188) patients, with increased depth for the exons encoding the regulatory region of the protein. A group of 31 infertile males with clinical history of uni- or bi-lateral cryptorchidism and one patient with anorchia were also analyzed. We found two WT1 missense substitutions at higher frequency in patients than in controls: (i) a novel variant in exon 1 (p.Pro130Leu) disrupting a mammalian-specific polyproline stretch within the self-association domain was more frequent in azoospermia (0.27% vs 0.13%; p=0.549); (ii) a rare variant in a conserved residue in close proximity to the first zinc finger (pCys350Arg) was more frequent in severe oligozoospermia (0.80% vs 0.13%; p=0.113). These results suggest a role for rare WT1 damaging variants in severe spermatogenic failure in populations of European ancestry and claim for large multicenter studies in order to fully assess the contribution of WT1 genetic alterations to male infertility in the absence of other disease phenotypes. Copyright © 2014 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.
    The Journal of Urology 11/2014; · 3.75 Impact Factor
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    ABSTRACT: As fertilization with unselected apoptotic spermatozoa may contribute to failures in assisted reproductive techniques, it has become essential to remove this type of sperm in order to increase the success rates. Magnetic-activated cell sorting (MACS) is a sperm preparation technique that isolates non-apoptotic spermatozoa based on the expression of phosphatidylserine in the membrane of apoptotic sperm. Therefore, we aimed to evaluate whether there was a significant decrease in sperm DNA fragmentation (sDNAfrag) and verify which protocol was the most efficient.
    Journal of Assisted Reproduction and Genetics 11/2014; · 1.82 Impact Factor
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    ABSTRACT: This article describes a patient with cryptorchidism and nonobstructive azoospermia presenting a novel microdeletion of approximately 1 Mb at 11p13. It was confirmed by multiplex ligation-dependent probe amplification that this heterozygous deletion spanned nine genes (WT1, EIF3M, CCDC73, PRRG4, QSER1, DEPDC7, TCP11L1, CSTF3 and HIPK3) and positioned the breakpoints within highly homologous repetitive elements. As far as is known, this is the smallest deletion as-yet described encompassing the WT1 gene and was detected only once in a total of 32 Portuguese patients with isolated uni- or bilateral cryptorchidism. These findings suggest that molecular analysis in patients with genitourinary features suggestive of WT1 impairment, namely cryptorchidism and renal abnormalities, may reveal cryptic genetic defects.
    Reproductive biomedicine online 09/2014; · 2.98 Impact Factor
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    ABSTRACT: The aim of this work was to present the clinical and embryological outcomes of 65 azoospermic patients with non-mosaic Klinefelter syndrome (KS), treated by testicular sperm extraction (TESE), followed by intracytoplasmic sperm injection (ICSI), either with fresh or cryopreserved testicular spermatozoa. In total, spermatozoa were recovered in 25/65 (38.5%) of the cases. Of the 48 patients who choose to perform TESE followed by ICSI using fresh testicular spermatozoa (treatment TESE), spermatozoa was recovered in 19 patients (40%), with birth of 12 newborn. Of the 17 patients who choose to perform TESE followed by testicular sperm cryopreservation, spermatozoa were recovered in six patients (35%), with birth of one child. Of the patients who performed treatment TESE, nine went for a new cycle using cryopreserved spermatozoa. Of these, five patients had a previous failed treatment cycle (two patients, three newborn) and four with a previous success went for a new cycle (one patient, one newborn). Overall, the embryological and clinical rates were as follows: 52% of fertilization, 41% of blastocyst, 27% of implantation, 39% of live birth delivery and 47% of newborn. Of the 16 clinical pregnancies, 14 had a successful delivery (12 girls and 5 boys). The 17 newborns had a mean gestation time of 37.2 weeks (35.3% pre-term) and a mean newborn weight of 2781.3 g (37.5% low weight). Comparisons between cycles with fresh and frozen-thaw spermatozoa revealed higher fertilization and clinical pregnancy rates with fresh spermatozoa, with no differences regarding implantation or newborn rates. Of the 17 newborns, no abnormal karyotypes (n = 3) or numerical abnormalities in chromosomes 13, 18, 21, X and Y (n = 14) as evaluated by Multiplex Ligation–dependent Probe Amplification were observed. In conclusion, this study presents further data that reassures that men with KS have no increased risk of transmitting their genetic problem to the offspring.
    Andrology 07/2014; 2(4). · 3.37 Impact Factor
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    ABSTRACT: Schistosomiasis is a neglected tropical disease, endemic in 76 countries, that afflicts more than 240 million people. The impact of schistosomiasis on infertility may be underestimated according to recent literature. Extracts of Schistosoma haematobium include estrogen-like metabolites termed catechol-estrogens that down regulate estrogen receptors alpha and beta in estrogen responsive cells. In addition, schistosome derived catechol-estrogens induce genotoxicity that result in estrogen-DNA adducts. These catechol estrogens and the catechol-estrogen-DNA adducts can be isolated from sera of people infected with S. haematobium. The aim of this study was to study infertility in females infected with S. haematobium and its association with the presence of schistosome-derived catechol-estrogens.
    PLoS ONE 05/2014; 9(5):e96774. · 3.53 Impact Factor
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    ABSTRACT: The role of estrogens in male reproductive physiology has been intensively studied over the few years. Yet, the involvement of their specific receptors has long been a matter of debate. The selective testicular expression of the classic nuclear estrogen receptors (ERα and ERβ) argues in favor of ER-specific functions in the spermatogenic event. Recently, the existence of a G protein-coupled estrogen receptor (GPR30) mediating non-genomic effects of estrogens has also been described. However, little is known about the specific testicular expression pattern of GPR30, as well as on its participation in the control of male reproductive function. Herein, by means of immunohistochemical and molecular biology techniques (RT-PCR and Western Blot), we aimed to present the first exhaustive evaluation of GPR30 expression in non-neoplastic human testicular cells. Indeed, we were able to demonstrate that GPR30 was expressed in human testicular tissue and that the staining pattern was consistent with its cytoplasmic localization. Additionally, by using cultured human Sertoli cells (SCs) and isolated haploid and diploid germ cells fractions, we confirmed that GPR30 is expressed in SCs and diploid germ cells but not in haploid germ cells. This specific expression pattern suggests a role for GPR30 in spermatogenesis.
    General and Comparative Endocrinology 05/2014; · 2.67 Impact Factor
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    ABSTRACT: The aim of the present study was to use fluorescence in situ hybridization to analyze the chromosome status of zygotes with a single pronucleus from in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) treatment cycles. In addition, we performed immunocytochemical detection of nuclear lamins and histone H3 trimethylated at lysine-9, Me(3)H3K9. Zygotes were processed 24 hours after insemination or injection to assure the absence of asynchrony. In opposition to previous results, we observed 2 pronuclei in 16 of 18 IVF zygotes and 40 of 64 ICSI zygotes, suggesting premature pronuclear breakdown. In IVF and ICSI zygotes, the rate of normal diploidy was only 6 of 16 and 27 of 56, respectively, suggesting that monopronucleated zygotes should not be used in assisted reproductive treatments. The possible mechanisms are discussed and compared to previous studies of monopronucleated zygotes.
    Reproductive sciences (Thousand Oaks, Calif.) 04/2014; · 2.18 Impact Factor
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    ABSTRACT: Summary Exposure to lead may cause changes in the male reproductive system. We evaluated the effect of lead chloride (PbCl2) in vitro on semen quality from 31 individuals. Samples were incubated at room temperature for two exposure times (4 h and 8 h) and with two concentrations of PbCl2 (15 μg/ml or 30 μg/ml). Results showed that PbCl2 significantly inhibited rapid progressive motility and caused an increase in the percentage of tail anomalies in both times and concentrations assessed, as well as a decrease in vitality in the group exposed to 30 μg/ml PbCl2. A significant increase in immotile sperm was also observed between the group control and the groups submitted to lead. Total motility and DNA fragmentation also showed a significant decrease and increase, respectively, after 4 h of incubation in the group exposed to 30 μg/ml and in both groups after 8 h of incubation. In conclusion, PbCl2 affected sperm parameters and DNA integrity, which are essential for male fertility.
    Zygote 02/2014; · 1.50 Impact Factor
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    ABSTRACT: Summary Human oocyte dysmorphisms attain a large proportion of retrieved oocytes from assisted reproductive technology (ART) treatment cycles. Extracytoplasmic defects involve abnormal morphology of the zona pellucida (ZP), perivitelline space and first polar body. The aim of the present study was to describe a novel dysmorphism affecting the ZP, indented ZP. We also evaluated the clinical, embryological and ultrastructural features of these cases. We evaluated all ART treatment cycles during 7 consecutive years and found 13 treatment cycles (six patients) with all oocytes presenting an indented ZP. In addition, these oocytes presented total or partial absence of the perivitelline space, absence of resistance to ZP and oolemma penetration during microinjection, and low ooplasm viscosity during aspiration. This novel described dysmorphism was recurrent and attained all oocytes in three cases that had more than one treatment cycle. When compared with controls, data showed significant low oocyte maturity (42% versus 81.6%) and high cycle cancellation (30.8% versus 8.5%) rates, normal degeneration (3.4% versus 6.3%) and fertilization rates (69% versus 69.5%), and low pregnancy (15.4% versus 33.3%) and live-birth delivery (7.7% versus 27.7%) rates per cycle. Ultrastructure analysis revealed a zona pellucida structure with large empty electrolucent regions, an outer ZP layer with an indented surface with protuberances and a thick inner ZP that obliterated the perivitelline space. There was evidence of exocytosis of ZP material by the oocyte. In conclusion, oocytes with this novel described dysmorphism (indented ZP) are associated with low maturity, pregnancy and live-birth delivery rates.
    Zygote 09/2013; · 1.50 Impact Factor
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    ABSTRACT: Bicarbonate (HCO3-) membrane transport systems are crucial players in the physiology of several tissues. The molecular basis of HCO3- membrane transport is of major physiological relevance since this ion is involved in the establishment of intracellular and extracellular ionic composition, osmolariy and pH. The membrane HCO3- transporters are divided in two main families: solute carrier 4 (SLC4) and solute carrier 26 (SLC26), although HCO3- concentration can also be regulated by the cystic fibrosis transmembrane regulator (CFTR). In most tissues the SLC4 family represents the majority of HCO3- transporters members, which can be divided in two subgroups: the Na+-dependent and the Na+-independent transporters. The SLC26 family consists of ten members that can transport diverse ions besides HCO3-. In the male reproductive tract, HCO3- transport occurs in several processes in order to assure a correct pursuance of the spermatogenetic event and spermatozoa capacitation, being also necessary for egg fertilization. Indeed, the formation of competent spermatozoa, the maintenance of an adequate ductal luminal milieu and spermatozoa capacitation are highly dependent of ionic balance and pH. Perturbations in these processes result in reduced male reproductive health and consequently male subfertility and/or infertility. Thus, it is imperative to understand HCO3- transport dynamics in order to identify and counteract possible alterations related with reduced male fertility caused by pathological conditions. Herein, we will review the major families and subfamilies of HCO3- membrane transport, discussing the molecular basis of HCO3- transport in the male reproductive tract and its role in male-associated subfertility and/or infertility.
    Current Medicinal Chemistry 08/2013; · 3.72 Impact Factor
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    ABSTRACT: Abstract Phosphorylation is a major regulatory mechanism in eukaryotic cells performed by the concerted actions of kinases and phosphatases (PPs). Protein phosphorylation has long been relevant to sperm physiology, from acquisition of motility in the epididymis to capacitation in the female reproductive tract. While the precise kinases involved in the regulation of sperm phosphorylation have been studied for decades, the PPs have only recently received research interest. Tyrosine phosphorylation was first implicated in the regulation of several sperm-related functions, from capacitation to oocyte binding. Only afterwards, in 1996, the inhibition of the serine/threonine-PP phosphoprotein phosphatase 1 (PPP1) by okadaic acid and calyculin-A was shown to initiate motility in caput epididymal sperm. Today, the current mechanisms of sperm motility acquisition based on PPP1 and its regulators are still far from being fully understood. PPP1CC2, specifically expressed in mammalian sperm, has been considered to be the only sperm-specific serine/threonine-PP, while other PPP1 isoforms were thought to be absent from sperm. This article examines the "Omics" of human sperm, and reports, for the first time, the identification of three new serine/threonine-protein PPs, PPP1CB, PPP4C, and PPP6C, in human sperm, together with two tyrosine-PPs, MKP1 and PTP1C. We specifically localized in sperm PPP1CB and PPP1CC2 from the PPP1 subfamily, and PPP2CA, PPP4C, and PPP6C from the PPP2 subfamily of the serine/threonine-PPs. A semi-quantitative analysis was performed to determine the various PPs' differential expression in sperm head and tail. These findings contribute to a comprehensive understanding of human sperm PPs, and warrant further research for their clinical and therapeutic significance.
    Omics: a journal of integrative biology 07/2013; · 2.29 Impact Factor
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    ABSTRACT: Efforts have been made for the isolation and characterization of human stem spermatogonia (SG) which would be of major interest for fertility preservation in oncologic patients. We evaluated the expression of mammalian SG stem cell markers, KIT, OCT4, integrin alpha 6 (ITGA6), and integrin beta 1 (ITGB1) as possible indicators for the isolation of those cells in humans. Two different types of SG were individually isolated by micromanipulation from testicular biopsies of men with conserved spermatogenesis. Expression of mRNA showed the absence of KIT and ITGB1 markers in SG. By immunocytochemistry (IC), protein expression for KIT and integrins revealed two types of SG populations, negative (type-1) and positive (type-2). By immunohistochemistry (IH), protein expression for KIT and ITGB1 also revealed two kinds of SG populations, negative (SG A-dark) and positive (SG A-pale). Results suggest that in humans it may be possible to obtain pure populations of stem SG by using negative KIT((-))/ITGB1((-)) sorting.
    Systems biology in reproductive medicine 06/2013; · 1.85 Impact Factor
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    ABSTRACT: Gonadal failure, along with early pregnancy loss and perinatal death, may be an important filter that limits the propagation of harmful mutations in the human population. We hypothesized that men with spermatogenic impairment, a disease with unknown genetic architecture and a common cause of male infertility, are enriched for rare deleterious mutations compared to men with normal spermatogenesis. After assaying genomewide SNPs and CNVs in 323 Caucasian men with idiopathic spermatogenic impairment and more than 1,100 controls, we estimate that each rare autosomal deletion detected in our study multiplicatively changes a man's risk of disease by 10% (OR 1.10 [1.04–1.16], p<2×10−3), rare X-linked CNVs by 29%, (OR 1.29 [1.11–1.50], p<1×10−3), and rare Y-linked duplications by 88% (OR 1.88 [1.13–3.13], p<0.03). By contrasting the properties of our case-specific CNVs with those of CNV callsets from cases of autism, schizophrenia, bipolar disorder, and intellectual disability, we propose that the CNV burden in spermatogenic impairment is distinct from the burden of large, dominant mutations described for neurodevelopmental disorders. We identified two patients with deletions of DMRT1, a gene on chromosome 9p24.3 orthologous to the putative sex determination locus of the avian ZW chromosome system. In an independent sample of Han Chinese men, we identified 3 more DMRT1 deletions in 979 cases of idiopathic azoospermia and none in 1,734 controls, and found none in an additional 4,519 controls from public databases. The combined results indicate that DMRT1 loss-of-function mutations are a risk factor and potential genetic cause of human spermatogenic failure (frequency of 0.38% in 1306 cases and 0% in 7,754 controls, p = 6.2×10−5). Our study identifies other recurrent CNVs as potential causes of idiopathic azoospermia and generates hypotheses for directing future studies on the genetic basis of male infertility and IVF outcomes.
    PLoS Genetics 03/2013; 9(3):e1003349. · 8.52 Impact Factor
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    ABSTRACT: PURPOSE: Little is known about the apoptotic mechanisms involved in abnormal spermatogenesis. In order to describe the significance of apoptosis in azoospermia, testicular tissue from abnormal spermatogenesis was analysed. METHODS: Testicular treatment biopsies were obtained from 27 men. Five presented oligozoospermia, 9 obstructive azoospermia (4 congenital bilateral absence of the vas deferens; 5 secondary azoospermia) and 13 non-obstructive azoospermia (5 hypospermatogenis; 3 maturation arrest; 5 Sertoli-cell-only syndrome). Immunohistochemical staining was performed for active caspases-3, -8 and -9. The presence of active caspases in Sertoli cells and germ cells was analyzed using stereological tools. RESULTS: Increased active caspase-3 was found in Sertoli-cell-only syndrome. No significant differences were found in maturation arrest. In hypospermatogenesis, primary spermatocytes were the germ cells with higher active caspases. Oligozoospermia and secondary obstruction showed significant differences among germ cells for the presence of all active caspases. In oligozoospermia, spermatogonia presented significant increased active caspase-9 in relation to active caspase-8. In primary obstruction and hypospermatogenesis, germ cells presented significant increased active caspases-3 and -9. CONCLUSIONS: Results suggest that increased active caspase-3 might be involved in Sertoli-cell-only syndrome etiology. In cases of hypospermatogenesis, intrinsic lesions at the meiotic stage seem to be related to the pathology. In secondary obstruction apoptosis is suggested to be initiated due to extrinsic and intrinsic lesions, whereas in primary obstruction only the intrinsic apoptotic pathway seems to be present. Finally, in oligozoospermic patients spermatogonia death by mitochondrial damage additionally to meiosis malfunctioning, might be on the origin of the decreased sperm output.
    Journal of Assisted Reproduction and Genetics 01/2013; · 1.82 Impact Factor
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    ABSTRACT: Chromosomal rearrangements are common in humans. Pericentric inversions are among the most frequent aberrations (1-2%). Most inversions are balanced and do not cause problems in carriers unless one of the breakpoints disrupts important functional genes, has near submicroscopic copy number variants or hosts "cryptic" complex chromosomal rearrangements. Pericentric inversions can lead to imbalance in offspring. Less than 3% of Down syndrome patients have duplication as a result of parental pericentric inversion of chromosome 21. We report a family with an apparently balanced pericentric inversion of chromosome 21. The proband, a 23-year-old female was referred for prenatal diagnosis at 16 weeks gestation because of increased nuchal translucency. She has a familial history of Down's syndrome and moderate intellectual disability, a personal history of four spontaneous abortions and learning difficulties. Peripheral blood and amniotic fluid samples were collected to perform proband´s and fetus cytogenetic analyses. Additionally, other six family members were evaluated and cytogenetic analysis was performed. Complementary FISH and MLPA studies were carried out using. An apparent balanced chromosome 21 pericentric inversion was observed in four family members, two revealed a recombinant chromosome 21 with partial trisomy, and one a full trisomy 21 with an inverted chromosome 21. Array CGH analysis was performed in the mother and the brother's proband. MLPA and aCGH studies identified a deletion of about 1,7Mb on the long arm of inverted chromosome 21q22.11. We believe the cause of the intellectual disability / learning difficulties observed in the members with the inversion is related to this deletion. The recombinant chromosome 21 has a partial trisomy including the DSCR with no deletion. The risk for carriers of having a child with multiple malformations/Intellectual disability is about 30% depending on whether and how this rearrangement interferes with meiosis.
    Gene 12/2012; · 2.20 Impact Factor
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    ABSTRACT: Congenital Adrenal Hyperplasia (CAH) due to 21-hydroxylase deficiency is a common autosomal recessive disorder caused by mutations in the steroid 21-hydroxylase gene (CYP21A2). Complete DNA sequencing of CYP21A2 was performed in 5 patients, 3 non-classic and 2 classic forms of the disease, that were previously screened for the 10 most common mutations, in order to detect additional mutations that could justify the phenotype of the patients. 5 mutations were identified with the whole gene extended analysis. The mutations, p.Pro432Leu and p.Ala434Glu, the first previously reported by our group and the second a novel one were structurally analyzed with ICM-Pro software regarding biochemical properties such as protein stability, accessibility to surface and hydrophobicity, in order to elucidate their effects on the CYP21A2 protein. The 2 affected residues, Pro432 and Ala434, were also studied for conservation purposes in order to predict the severity of both mutations with PolyPhen-2 software and were considered as "probably damaging". Prediction of clinical severity, based on molecular modelling and sequence conservation, was in accordance with the patient's clinical diagnosis.
    Experimental and Clinical Endocrinology & Diabetes 10/2012; 120(9):535-9. · 1.76 Impact Factor
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    ABSTRACT: Cystic fibrosis is the most frequent autosomal recessive disease in the Caucasian population, with an incidence of 1:2500 newborn and a frequency of 1:25. The associated gene is Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) and it encodes the CFTR protein that functions as a chloride (Cl(-)) channel. It is found in the apical membrane of exocrine epithelial cells, responsible for the regulation of the movement of water and solutes through biological membranes. To our knowledge, there are no studies on protein localization in the different cell types of the seminiferous epithelium with different pathologies. The aim of the present study was to analyze the expression of the CFTR protein in the human seminiferous epithelium of infertile males with different pathologies. CFTR protein expression was studied by immunohistochemistry in paraffin sections of testicular biopsies of six infertile men: Sertoli cell only syndrome, maturation arrest, secondary obstructive azoospermia, primary obstructive azoospermia due to congenital bilateral absence of the vas deferens (CBAVD), severe oligozoospermia, and retrograde ejaculation. All cell types of the seminiferous epithelium were studied: Sertoli cells, spermatogonia, primary spermatocytes at the leptotene/zygotene and at the pachytene stages, secondary spermatocytes, round, elongating and elongated spermatids, and spermatozoa. With the exception of sperm, all cells were labeled in the cytoplasm and in the cytoplasmic membrane. In the patient with CBAVD labeling was light at the cell membrane and absent in the cytoplasm of Sertoli cells and diploid germ cells. Generally, labeling was stronger after the diploid stage, which is probably related to cell volume reduction during spermiogenesis. The results obtained also suggest that the CFTR protein may impact CBAVD spermatogenesis and other pathologies.
    Systems biology in reproductive medicine 09/2012; · 1.85 Impact Factor
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    ABSTRACT: Spermatogenesis is a complex process of cell proliferation, meiosis and differentiation. In order to determine the genetic mechanisms that control this process we need to develop adequate methodologies for the purification of stage-specific germ cells. In this study we aim to evaluate four markers (c-kit, oct-4, Integrin α6 and Integrin β1), used to isolate spermatogonial stem cells in mammals, as possible markers to isolate/sort testicular adult stem and progenitor cells in humans.
    Microscopy and Microanalysis 08/2012; 18(S5):15-16. · 1.76 Impact Factor

Publication Stats

2k Citations
427.91 Total Impact Points

Institutions

  • 1991–2014
    • University of Porto
      • Faculty of Medicine
      Oporto, Porto, Portugal
  • 2009–2011
    • Universidade da Beira Interior
      • Research Centre of Health Sciences (CICS)
      Ковильян, Castelo Branco, Portugal
    • Institut Marqués, Spain, Barcelona
      Barcino, Catalonia, Spain
  • 2002
    • Universität Heidelberg
      • Institute of Human Genetics
      Heidelberg, Baden-Wuerttemberg, Germany
  • 2001–2002
    • Porto Military Hospital
      Oporto, Porto, Portugal
  • 1996
    • University of Granada
      • Facultad de Ciencias
      Granada, Andalusia, Spain