Objectives To evaluate the relationship between microdeletion or mutation on the Y chromosome and Chinese patients with idiopathic azoospermia and severe oligozoospermia and to establish a molecular detection method....Objectives To evaluate the relationship between microdeletion or mutation on the Y chromosome and Chinese patients with idiopathic azoospermia and severe oligozoospermia and to establish a molecular detection method.Methods Microdeletion or mutation detection at the AZFa (sY84 and USP9Y), AZFb, AZFc/DAZ and SRY regions of the Y chromosome. Seventy-three azoospermia and 28 severe oligozoospermia patients were evaluated using PCR and PCR-SSCP techniques.Results Twelve of 101 patients (12%) with the AZFc/DAZ microdeletion were found, including 8 with azoospermia (11%) and 4 with severe oligozoospermia (14.3%), and 1 patient had a AZFb and AZFc/DAZ double deletion. No deletions in the AZFa or SRY regions were found. No deletions in AZFa, AZFb, AZFc/DAZ or SRY regions were found in 60 normal men who had produced one or more children.Conclusions Microdeletion on the Y chromosome, especially at its AZFc/DAZ regions, may be a major cause of azoospermia and severe oligozoospermia leading to male infertility in China. It is recommended that patients have genetic counseling and microdeletion detection on the Y chromosome before intracytoplasmic sperm injection.展开更多
Since the first demonstration of sperm entry into the fertilized eggs of Mediterranean sea urchin Paracentrotus lividus by Hertwig(1876),enormous progress and insights have been made on this topic.However,the precise ...Since the first demonstration of sperm entry into the fertilized eggs of Mediterranean sea urchin Paracentrotus lividus by Hertwig(1876),enormous progress and insights have been made on this topic.However,the precise molecular mechanisms underlying fertilization are largely unknown.The two most dramatic changes taking place in the zygote immediately after fertilization are:(i) a sharp increase of intracellular Ca2+ that initiates at the sperm interaction site and traverses the egg cytoplasm as a wave,and(ii) the concomitant dynamic rearrangement of the actin cytoskeleton.Traditionally,this has been studied most extensively in the sea urchin eggs,but another echinoderm,starfish,whose eggs are much bigger and transparent,has facilitated experimental approaches using microinjection and fluorescent imaging methodologies.Thus in starfish,it has been shown that the sperm-induced Ca2+ increase in the fertilized egg can be recapitulated by several Ca2+ -evoking second messengers,namely inositol 1,4,5-trisphosphate(InsP3) ,cyclic ADP-ribose(cADPr) and nicotinic acid adenine dinucleotide phosphate(NAADP) ,which may play distinct roles in the generation and propagation of the Ca2+ waves.Interestingly,it has also been found that the dynamic rearrangement of the actin cytoskeleton in the fertilized eggs plays pivotal roles in guiding monospermic sperm entry and in the fine modulation of the intracellular Ca2+ signaling.As it is well known that Ca2+ regulates the structure of the actin cytoskeleton,our finding that Ca2+ signaling can be reciprocally affected by the state of the actin cytoskeleton raises an intriguing possibility that actin and Ca2+ signaling may form a'positive feedback loop'that accelerates the downstream events of fertilization.Perturbation of the cortical actin networks also inhibits cortical granules exocytosis.Polymerizing actin bundles also compose the'acrosome process,'a tubular structure protruding from the head of fertilizing sperm. Hence,actin,which is one of the most strictly conserved proteins in eukaryotes,modulates almost all major aspects of fertilization.展开更多
文摘Objectives To evaluate the relationship between microdeletion or mutation on the Y chromosome and Chinese patients with idiopathic azoospermia and severe oligozoospermia and to establish a molecular detection method.Methods Microdeletion or mutation detection at the AZFa (sY84 and USP9Y), AZFb, AZFc/DAZ and SRY regions of the Y chromosome. Seventy-three azoospermia and 28 severe oligozoospermia patients were evaluated using PCR and PCR-SSCP techniques.Results Twelve of 101 patients (12%) with the AZFc/DAZ microdeletion were found, including 8 with azoospermia (11%) and 4 with severe oligozoospermia (14.3%), and 1 patient had a AZFb and AZFc/DAZ double deletion. No deletions in the AZFa or SRY regions were found. No deletions in AZFa, AZFb, AZFc/DAZ or SRY regions were found in 60 normal men who had produced one or more children.Conclusions Microdeletion on the Y chromosome, especially at its AZFc/DAZ regions, may be a major cause of azoospermia and severe oligozoospermia leading to male infertility in China. It is recommended that patients have genetic counseling and microdeletion detection on the Y chromosome before intracytoplasmic sperm injection.
文摘Since the first demonstration of sperm entry into the fertilized eggs of Mediterranean sea urchin Paracentrotus lividus by Hertwig(1876),enormous progress and insights have been made on this topic.However,the precise molecular mechanisms underlying fertilization are largely unknown.The two most dramatic changes taking place in the zygote immediately after fertilization are:(i) a sharp increase of intracellular Ca2+ that initiates at the sperm interaction site and traverses the egg cytoplasm as a wave,and(ii) the concomitant dynamic rearrangement of the actin cytoskeleton.Traditionally,this has been studied most extensively in the sea urchin eggs,but another echinoderm,starfish,whose eggs are much bigger and transparent,has facilitated experimental approaches using microinjection and fluorescent imaging methodologies.Thus in starfish,it has been shown that the sperm-induced Ca2+ increase in the fertilized egg can be recapitulated by several Ca2+ -evoking second messengers,namely inositol 1,4,5-trisphosphate(InsP3) ,cyclic ADP-ribose(cADPr) and nicotinic acid adenine dinucleotide phosphate(NAADP) ,which may play distinct roles in the generation and propagation of the Ca2+ waves.Interestingly,it has also been found that the dynamic rearrangement of the actin cytoskeleton in the fertilized eggs plays pivotal roles in guiding monospermic sperm entry and in the fine modulation of the intracellular Ca2+ signaling.As it is well known that Ca2+ regulates the structure of the actin cytoskeleton,our finding that Ca2+ signaling can be reciprocally affected by the state of the actin cytoskeleton raises an intriguing possibility that actin and Ca2+ signaling may form a'positive feedback loop'that accelerates the downstream events of fertilization.Perturbation of the cortical actin networks also inhibits cortical granules exocytosis.Polymerizing actin bundles also compose the'acrosome process,'a tubular structure protruding from the head of fertilizing sperm. Hence,actin,which is one of the most strictly conserved proteins in eukaryotes,modulates almost all major aspects of fertilization.
