Mitochondrial DNA content varies considerably in oocytes, even when collected from the same patient. In the present study, real-time quantitative polymerase chain reaction analysis of 113 unfertilized oocytes obtained from 43 patients revealed an average of 193,000 (range: 20,000 to 598,000) mitochondrial genomes per cell. We compared several groups of oocytes to investigate the relationship between mitochondrial DNA content and fertilizability. The average mitochondrial DNA copy number was significantly lower in cohorts suffering from fertilization failure compared to cohorts with a normal rate of fertilization. In addition, the mitochondrial copy number of oocytes from patients with fertilization failure due to unknown causes was significantly lower than that of oocytes from patients in which IVF failure was due mainly to a severe sperm defect. The lower mtDNA copy number could be due to defective cytoplasmic maturation of oocytes. We conclude that low mitochondrial DNA content, due to inadequate mitochondrial biogenesis or cytoplasmic maturation, may adversely affect oocyte fertilizability.
A large and heterogeneous sample of 364 homeless adolescents was interviewed about residential and family histories, as well as about their experiences while homeless.They were also administered a diagnostic interview and various self-report measures of emotional and behavioral functioning. Analyses were conducted to provide a better description of these youth, with a special focus on gender and age heterogeneity. Results of analyses suggested that homeless youth came from generally troubled backgrounds and had elevated rates of psychiatric disorders. For boys, their histories typically included physical abuse during childhood, physical assault on the street, and elevated rates of externalizing disorders. For girls, histories were more often marked by sexual abuse during childhood, sexual victimization on the streets, and elevated rates of internalizing disorders. Implications of these results for service delivery are discussed.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.