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Featured researches published by A. Ao.


Molecular Human Reproduction | 2008

Platelet-derived growth factors (PDGF-A and -B) and their receptors in human fetal and adult ovaries

H. Pinkas; Benjamin Fisch; G. Rozansky; Carmela Felz; Gania Kessler-Icekson; Haim Krissi; Shmuel Nitke; A. Ao; Ronit Abir

There is no information regarding the presence of platelet-derived growth factors (PDGFs) and their receptors in human ovaries. The expression of PDGF-A, -B and their two receptors, PDGFR-alpha and -beta, was investigated in ovarian samples from women/girls and from human fetuses, at the protein and mRNA levels. The samples were prepared for immunohistochemical staining for PDGF-A and -B and their two receptors and in situ hybridization for the detection of the mRNA transcripts of the receptors. Total RNA was extracted from frozen ovarian samples, and the expression of PDGF-A and -B was investigated by reverse transcription-polymerase chain reaction. The proteins for PDGF-A and -B were detected in oocytes, and in granulosa cells (GC) of 50% of the follicles from women/girls. The proteins and mRNA transcripts for the two receptors were detected in oocytes (mRNA for PDGFR-beta only in 25% of the oocytes). PDGFR-alpha mRNA was expressed in GC of a minority of the samples from women/girls, whereas PDGFR-beta protein and mRNA were identified in over 50% of the GC from this source. PDGF-A and -B transcripts were identified in all the extracts. The presence of the receptors in GC suggests that PDGFs might be involved in the activation of primordial follicles.


Molecular Human Reproduction | 2016

The importance of neuronal growth factors in the ovary

S. Streiter; Benjamin Fisch; B. Sabbah; A. Ao; Ronit Abir

The neurotrophin family consists of nerve growth factor (NGF), neurotrophin 3 (NT3) and neurotrophin 4/5 (NT4/5), in addition to brain-derived neurotrophic factor (BDNF) and the neuronal growth factors, glial cell line-derived neurotrophic factor (GDNF) and vasointestinal peptide (VIP). Although there are a few literature reviews, mainly of animal studies, on the importance of neurotrophins in the ovary, we aimed to provide a complete review of neurotrophins as well as neuronal growth factors and their important roles in normal and pathological processes in the ovary. Follicular assembly is probably stimulated by complementary effects of NGF, NT4/5 and BDNF and their receptors. The neurotrophins, GDNF and VIP and their receptors have all been identified in preantral and antral follicles of mammalian species, including humans. Transgenic mice with mutations in the genes encoding for Ngf, Nt4/5 and Bdnf and their tropomyosin-related kinase β receptor showed a reduction in preantral follicles and an abnormal ovarian morphology, whereas NGF, NT3, GDNF and VIP increased the in vitro activation of primordial follicles in rats and goats. Additionally, NGF, NT3 and GDNF promoted follicular cell proliferation; NGF, BDNF and VIP were shown to be involved in ovulation; VIP inhibited follicular apoptosis; NT4/5, BDNF and GDNF promoted oocyte maturation and NGF, NT3 and VIP stimulated steroidogenesis. NGF may also exert a stimulatory effect in ovarian cancer and polycystic ovarian syndrome (PCOS). Low levels of NGF and BDNF in follicular fluid may be associated with diminished ovarian reserve and high levels with endometriosis. More knowledge of the roles of neuronal growth factors in the ovary has important implications for the development of new therapeutic drugs (such as anti-NGF agents) for ovarian cancer and PCOS as well as various infertility problems, warranting further research.


Molecular Human Reproduction | 2008

Keratinocyte growth factor and its receptor in human ovaries from fetuses, girls and women

Ronit Abir; Benjamin Fisch; Xiao Yun Zhang; Carmela Felz; Gania Kessler-Icekson; Haim Krissi; Shmuel Nitke; A. Ao

Keratinocyte growth factor (KGF) promotes growth of rat pre-antral follicles. There is limited information regarding its presence or that of its unique receptor (KGFR) in human ovaries, specifically in pre-antral follicles. The aim of the study was to investigate the expression of KGF and KGFR in ovarian samples from human fetuses and girls/women. The samples were prepared for immunohistochemical study of the KGF protein and for in situ hybridization to localize mRNA transcripts of KGFR. Total RNA was extracted from frozen ovarian samples, and the expression of KGF mRNA transcripts was investigated by reverse transcriptase polymerase chain reaction. In both fetuses and girls/women, the protein for KGF was detected from primordial stages in oocytes, granulosa cells (GCs) and stroma cells. Its mRNA transcripts were also detected in all extracts. The mRNA transcripts for KGFR were detected mainly in stroma cells in ovarian samples from both sources; in 10% of the samples, follicular staining was noted also in oocytes and GCs. Further studies adding KGF to the culture medium are needed to elucidate its putative role in human primordial follicle activation.


Journal of Assisted Reproduction and Genetics | 2001

Direct Comparison of Detection Systems Used for the Development of Single-Cell Genetic Tests in Preimplantation Genetic Diagnosis

Deborah L. Blake; Nicola Dean; Casey Knight; Seang Lin Tan; A. Ao

AbstractPurpose: Single-cell polymerase chain reaction (PCR) requires efficient amplification and accurate detection. We compare the accuracy of heteroduplex, fluorescent-fragment, and fluorescent single-strand conformation polymorphism (F-SSCP) analysis as detection systems for analysis of a PCR assay developed for preimplantation genetic diagnosis. Methods: A single-cell, fluorescent multiplex PCR assay was developed for the cystic fibrosis ΔF508 mutation and the short tandem repeat, D21S11. Detection systems were compared by analyzing blinded PCR products. Results: Amplification rates for cystic fibrosis were 89% by heteroduplex and 91% by fragment analysis, while it was 72% for D21S11 by fragment analysis. No difference in allele dropout was detected for cystic fibrosis by any method (2%). Overall accuracy was high, >97%, although SSCP was the least accurate. Conclusions: Heteroduplex and fragment analysis proved equal in the diagnosis of a single amplified locus. We determined that fragment analysis allows maximal accuracy of detection and permits analysis of a second loci, controlling for DNA contamination and allelic dropout.


Expert Review of Neurotherapeutics | 2002

Genetic prenatal and preimplantation diagnosis of trinucleotide repeat disorders

Nicola Dean; A. Ao

This review examines the history, present status and future of genetic antenatal diagnosis for the trinucleotide repeat disorders, including Huntington′s disease, Fragile X syndrome and myotonic dystrophy. Conventional prenatal diagnosis and the relatively new field of preimplantation genetic diagnosis, which can diagnose an affected embryo before a pregnancy is established, are described. Genetic diagnosis for these late onset diseases has inherent difficulties and many controversies. However, antenatal diagnosis is an important service for an individual with one of these mutations, who wishes to prevent the birth of an affected child.


Molecular Human Reproduction | 2005

Presence of NGF and its receptors in ovaries from human fetuses and adults

Ronit Abir; Benjamin Fisch; Shaoguang Jin; M. Barnnet; Avi Ben-Haroush; Carmela Felz; Gania Kessler-Icekson; Dov Feldberg; Shmuel Nitke; A. Ao


Molecular Human Reproduction | 1999

Assessment of multiplex fluorescent PCR for screening single cells for trisomy 21 and single gene defects

Deborah L. Blake; Seang Lin Tan; A. Ao


Molecular Human Reproduction | 2006

Tyrosine kinase B receptor and its activated neurotrophins in ovaries from human fetuses and adults.

S. Harel; Shaoguang Jin; Benjamin Fisch; Dov Feldberg; H. Krissi; Carmela Felz; S. Freimann; S.L. Tan; A. Ao; Ronit Abir


Molecular Human Reproduction | 2001

The development of preimplantation genetic diagnosis for myotonic dystrophy using multiplex fluorescent polymerase chain reaction and its clinical application

N.L. Dean; Seang Lin Tan; A. Ao


Human Reproduction | 2002

Reported relationship between increased CTG repeat lengths in myotonic dystrophy and azoospermia

Nicola Dean; Simon Phillips; Peter Chan; S.L. Tan; A. Ao

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