1/26. A trisomic germ cell line and precocious chromatid segregation leads to recurrent trisomy 21 conception.A chromosomally normal 37-year-old woman was referred for preimplantation genetic diagnosis after having several conceptuses with trisomy 21. Segregation of chromosome 21 was assessed in unfertilised meiosis II oocytes and preimplantation embryos from PGD cycles using fluorescent in situ hybridisation (FISH). Of 7 preimplantation embryos, 5 were chromosomally abnormal with 4 having trisomy 21 and one being tetraploid. Of 4 oocytes, 3 had an abnormal chromosomal constitution with either an extra chromosome 21 or an extra chromatid 21. In one oocyte an extra chromatid 21 was detected in both the metaphase II complement and the first polar body providing the first direct evidence of a maternal trisomic germ cell line. Moreover, this result shows that the extra chromosome 21 can precociously divide into its two chromatids at the first meiotic division.- - - - - - - - - - ranking = 1keywords = conception (Clic here for more details about this article) |
2/26. Recurrent cholestasis following ovarian hyperstimulation syndrome: case report.This is a case report illustrating a patient who developed recurrent cholestasis during a twin pregnancy following in-vitro fertilization (IVF) treatment. On the first occasion cholestasis developed unusually in the first trimester, and on the second occasion, it presented in the way that obstetric cholestasis (OC) is commonly seen in the third trimester.- - - - - - - - - - ranking = 9.5174597529052keywords = fertilization (Clic here for more details about this article) |
3/26. Ceasing of movement-disorder attacks immediately after the onset of pregnancy: possible effect of human chorionic gonadotropin.In a woman with paroxysmal kinesiogenic choreoathetosis, attacks ceased within a few days after conception. An effect of human chorionic gonadotrophin is assumed, since this hormone decreased sodium currents and excessive action potential generation in an experimental approach.- - - - - - - - - - ranking = 0.25keywords = conception (Clic here for more details about this article) |
4/26. Managing urinary tract infections in men.Despite the obvious genitourinary differences between the sexes, management of lower urinary tract infections in men is based largely on standards developed from studies in women. This has helped foster misconceptions that, among other problems, add needless complexity and expense to diagnosis and treatment of male patients.- - - - - - - - - - ranking = 0.25keywords = conception (Clic here for more details about this article) |
5/26. Repetitive complete hydatidiform mole can be biparental in origin and either male or female.Complete hydatidiform mole (CHM) is an abnormality in pregnancy due to a diploid conception which is generally androgenetic in origin, i. e. all 46 chromosomes are paternally derived. We have examined the genetic origin of repetitive hydatidiform moles in a patient having three CHM by two different partners, and no normal pregnancies. Using fluorescent microsatellite genotyping, we have shown all three CHM to be biparental, rather than androgenetic, in origin. Examination of informative markers for each homologous pair of chromosomes, in two of the CHM, failed to reveal any evidence of unipaternal disomy, suggesting that the molar phenotype might result from disruption of normal imprinting patterns due to a defect in the maternal genome. It has been suggested that intracytoplasmic sperm injection (ICSI), followed by selection of male embryos, can prevent repetitive CHM; but examination of sex chromosome-specific sequences in the three CHM described here, showed that, while two were female, the first CHM was male. Selection of male embryos is therefore unlikely to prevent repetitive CHM in this patient. Our results suggest that the genetic origin of repetitive CHM should be determined prior to in-vitro fertilization (IVF) and that current strategies for the prevention of repetitive CHM may not be appropriate where the CHM are of biparental origin.- - - - - - - - - - ranking = 9.7674597529052keywords = fertilization, conception (Clic here for more details about this article) |
6/26. Recurrent trisomy 21 in a couple with a child presenting trisomy 21 mosaicism and maternal uniparental disomy for chromosome 21 in the euploid cell line.recurrence of trisomy 21 was observed in a family in which both parents had a normal chromosome complement. Mosaic trisomy 21 was found in a blood karyotype of the first child, a second pregnancy ended in spontaneous abortion, and a full trisomy 21 was found at prenatal diagnosis of the third pregnancy of this same couple. Although recurrent trisomy 21 may be due to chance, the possibility of germline mosaicism for trisomy 21 in one of the parents has important implications for recurrence risk. Molecular analysis was therefore undertaken in this family to determine the parental origin and the stage of nondisjunction of the extra chromosome 21 in both cases. Although a maternal origin of both instances of trisomy 21 was observed, the mosaic case showed homozygosity for all markers along the duplicated maternal chromosome. Such a finding would normally suggest a postzygotic origin of the trisomy 21. However, the diploid cell line in this same case showed maternal uniparental disomy 21, implying that it was the result of a trisomic conception. We suggest that a somatic nondisjunction in the maternal germ cells is the most likely explanation for these findings. The apparent meiotic II stage of nondisjunction of the nonmosaic trisomy 21 fetus was consistent with maternal mosaicism. A review of the literature for recurrent trisomy 21 cases studied by molecular means, suggests that mosaicism in germ cells may account for more cases than is detected cytogenetically. These results also show that dna marker analysis does not provide a valuable tool for patient counseling in case of recurrent trisomy 21.- - - - - - - - - - ranking = 0.25keywords = conception (Clic here for more details about this article) |
7/26. Perceptions of acne vulgaris in final year medical student written examination answers.Misconceptions exist in the community regarding factors that exacerbate acne vulgaris. In particular stress, diet, lifestyle and personal hygiene are often erroneously claimed to be important factors. In order to investigate whether these common misconceptions persist in medical graduates, we analysed the answers of 215 sixth year medical students, who all subsequently graduated from The University of Melbourne, to a short-answer question on acne management and exacerbating factors in one of their final year examination papers. With respect to exacerbating factors, 67% of students identified stress, 10% identified lifestyle factors (smoking and alcohol consumption), and 25% claimed poor facial hygiene exacerbated acne. diet was stated to be an important factor by 41% of students, of whom 12% specifically mentioned chocolate. Persistence of these misconceptions among medical graduates is likely to perpetuate misinformation in the community.- - - - - - - - - - ranking = 0.75keywords = conception (Clic here for more details about this article) |
8/26. Neonatal hyperthyroidism in infants of mothers previously thyroidectomized due to Graves' disease.Neonatal hyperthyroidism generally arises as a result of active maternal Graves' disease via transplacental passage of thyroid stimulating immunoglobulins (TSI). On occasions, production of these antibodies may continue after thyroid ablation, either surgically or with radioiodine therapy. We present data concerning three patients (two of them twins) whose mothers had previously undergone near-total thyroidectomy prior to conception. Two of the neonates had neonatal hyperthyroidism due to persistence of TSI in the mother, and the third due to relapse of the maternal Graves' disease during pregnancy. We recommend monitoring- - - - - - - - - - ranking = 0.25keywords = conception (Clic here for more details about this article) |
9/26. A mutation in the follicle-stimulating hormone receptor as a cause of familial spontaneous ovarian hyperstimulation syndrome.ovarian hyperstimulation syndrome (OHSS) occurs mainly after excessive stimulation of the ovaries by exogenous gonadotropins administrated in the context of in vitro fertilization procedures (iatrogenic OHSS). Recently, spontaneous and recurrent occurrence of the disease (spontaneous OHSS) was shown in two families to be caused by mutations affecting the follitropin receptor (FSHr). The two mutant FSHr (T449I, D567N) harbor aminoacid substitutions in the serpentine portion of the receptor and display abnormally high sensitivity to the pregnancy hormone hCG, thus providing a satisfactory explanation to the phenotype. In addition, mutant D567N showed also increased sensitivity to thyrotopin (TSH) and displayed increase in basal (ligand-independent) activity. In this report, we describe a new familial case of recurrent OHSS. The affected women were heterozygous for a different mutation involving codon 449, where an alanine was substituted for threonine. Similar to D567N, the T449A FSHr mutant shows an increase of its sensitivity to both hCG and TSH, together with an increase in basal activity. Together with the two previous studies, this report shows that inappropriate stimulation of the FSHr by hCG is a cause of spontaneous OHSS.- - - - - - - - - - ranking = 9.5174597529052keywords = fertilization (Clic here for more details about this article) |
10/26. A mutation in the follicle-stimulating hormone receptor as a cause of familial spontaneous ovarian hyperstimulation syndrome.ovarian hyperstimulation syndrome (OHSS) occurs mainly after excessive stimulation of the ovaries by exogenous gonadotropins administrated in the context of in vitro fertilization procedures (iatrogenic OHSS). Recently, spontaneous and recurrent occurrence of the disease (spontaneous OHSS) was shown in two families to be caused by mutations affecting the follitropin receptor (FSHr). The two mutant FSHr (T449I, D567N) harbor aminoacid substitutions in the serpentine portion of the receptor and display abnormally high sensitivity to the pregnancy hormone hCG, thus providing a satisfactory explanation to the phenotype. In addition, mutant D567N showed also increased sensitivity to thyrotopin (TSH) and displayed increase in basal (ligand-independent) activity. In this report, we describe a new familial case of recurrent OHSS. The affected women were heterozygous for a different mutation involving codon 449, where an alanine was substituted for threonine. Similar to D567N, the T449A FSHr mutant shows an increase of its sensitivity to both hCG and TSH, together with an increase in basal activity. Together with the two previous studies, this report shows that inappropriate stimulation of the FSHr by hCG is a cause of spontaneous OHSS.- - - - - - - - - - ranking = 9.5174597529052keywords = fertilization (Clic here for more details about this article) |
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