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Abstract
The Rho GTPase-activating proteins (RhoGAPs) are a family of multifunctional molecules that transduce diverse intracellular signals by regulating Rho GTPase activities. A novel RhoGAP family member, p200RhoGAP, is cloned in human and mouse. The murine p200RhoGAP shares 86% sequence identity with the human homolog. In addition to a conserved RhoGAP domain at the N terminus, multiple proline-rich motifs are found in the C-terminal region of the molecules. Northern blot analysis revealed a brain-specific expression pattern of p200RhoGAP. The RhoGAP domain of p200RhoGAP stimulated the GTPase activities of Rac1 and RhoA in vitro and in vivo, and the conserved catalytic arginine residue (Arg-58) contributed to the GAP activity. Expression of the RhoGAP domain of p200RhoGAP in Swiss 3T3 fibroblasts inhibited actin stress fiber formation stimulated by lysophosphatidic acid and platelet-derived growth factor-induced membrane ruffling but not Bradykinin-induced filopodia formation. Endogenous p200RhoGAP was localized to cortical actin in naive N1E-115 neuroblastoma cells and to the edges of extended neurites of differentiated N1E-115 cells. Transient expression of the RhoGAP domain and the full-length molecule, but not the catalytic arginine mutants, readily induced a differentiation phenotype in N1E-115 cells. Finally, p200RhoGAP was capable of binding to the Src homology 3 domains of Src, Crk, and phospholipase Cgamma in vitro and became tyrosine-phosphorylated upon association with activated Src in cells. These results suggest that p200RhoGAP is involved in the regulation of neurite outgrowth by exerting its RhoGAP activity and that its cellular activity may be regulated through interaction with Src-like tyrosine kinases.
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Abstract
Rho family small GTPases serve as molecular switches involved in the regulation of diverse cellular functions including various cytoskeleton-related events and gene transcription. The Rho GTPase-activating proteins (RhoGAPs) are one of the major classes of regulators of Rho GTPases found in all eukaryotes that are crucial in cell cytoskeletal organization, growth, differentiation, neuronal development and synaptic functions. Recent studies have implicated them as specific negative regulators of Rho protein signalling pathways and provided insight into how the RhoGAP-catalysed GTPase-activating reaction might proceed. Progress has also been made in understanding how various intracellular signals might converge on or diverge from RhoGAPs leading to their tight regulation or GAP-independent function.
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Serial diffusion-weighted MR Imaging in delayed postanoxic encephalopathy. A case study. J Neuroradiol 2002; 29:211-5. [PMID: 12447148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/27/2023]
Abstract
We report a case of delayed postanoxic encephalopathy (DPE) studied with serial diffusion weighted imaging five times in a one-year period along with apparent diffusion coefficient (ADC) map as well as ADC values of periventricular white matter. Compared to the normal value, the ADC values of the white matter were initially low on the three (0.68 +/- 0.08 x 10(-3) mm(2)/s) and seven-week images (0.67 +/- 0.08 x 10(-3) mm(2)/s) but gradually recovered to the normal range on the four, six, and twelve-month images (0.78 +/- 0.05, 0.80 +/- 0.05 and 0.87 +/- 0.11 x 10(-3) mm(2)/s, respectively). Among the several pathogenetic mechanisms associated with DPE, these serial changes may be consistent with cytotoxic edema, from apoptosis, triggered by hypoxia.
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Na,K-ATPase activity is required for formation of tight junctions, desmosomes, and induction of polarity in epithelial cells. Mol Biol Cell 2001; 12:3717-32. [PMID: 11739775 PMCID: PMC60750 DOI: 10.1091/mbc.12.12.3717] [Citation(s) in RCA: 140] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2001] [Revised: 09/07/2001] [Accepted: 09/24/2001] [Indexed: 11/11/2022] Open
Abstract
Na,K-ATPase is a key enzyme that regulates a variety of transport functions in epithelial cells. In this study, we demonstrate a role for Na,K-ATPase in the formation of tight junctions, desmosomes, and epithelial polarity with the use of the calcium switch model in Madin-Darby canine kidney cells. Inhibition of Na,K-ATPase either by ouabain or potassium depletion prevented the formation of tight junctions and desmosomes and the cells remained nonpolarized. The formation of bundled stress fibers that appeared transiently in control cells was largely inhibited in ouabain-treated or potassium-depleted cells. Failure to form stress fibers correlated with a large reduction of RhoA GTPase activity in Na,K-ATPase-inhibited cells. In cells overexpressing wild-type RhoA GTPase, Na,K-ATPase inhibition did not affect the formation of stress fibers, tight junctions, or desmosomes, and epithelial polarity developed normally, suggesting that RhoA GTPase is an essential component downstream of Na,K-ATPase-mediated regulation of these junctions. The effects of Na,K-ATPase inhibition were mimicked by treatment with the sodium ionophore gramicidin and were correlated with the increased intracellular sodium levels. Furthermore, ouabain treatment under sodium-free condition did not affect the formation of junctions and epithelial polarity, suggesting that the intracellular Na(+) homeostasis plays a crucial role in generation of the polarized phenotype of epithelial cells. These results thus demonstrate that the Na,K-ATPase activity plays an important role in regulating both the structure and function of polarized epithelial cells.
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CsRn1, a novel active retrotransposon in a parasitic trematode, Clonorchis sinensis, discloses a new phylogenetic clade of Ty3/gypsy-like LTR retrotransposons. Mol Biol Evol 2001; 18:1474-83. [PMID: 11470838 DOI: 10.1093/oxfordjournals.molbev.a003933] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We screened the genome of a trematode, Clonorchis sinensis, in order to identify novel retrotransposons and thereby provide additional information on retrotransposons for comprehensive phylogenetic study. Considering the vast potential of retrotransposons to generate genetically variable regions among individual genomes, randomly amplified polymorphic DNAs (RAPDs) detected by arbitrarily primed polymerase chain reactions were selected as candidates for retrotransposon-related sequences. From RAPD analysis, we isolated and characterized a novel retrotransposon in C. sinensis as the first member of uncorrupted long-terminal-repeat (LTR) retrotransposons in phylum Platyhelminthes. The retrotransposon, which was named Clonorchis sinensis Retrotransposon 1 (CsRn1), showed a genomewide distribution and had a copy number of more than 100 per haploid genome. CsRn1 encoded an uninterrupted open reading frame (ORF) of 1,304 amino acids, and the deduced ORF exhibited similarities to the pol proteins of Ty3/gypsy-like LTR retrotransposons. The mobile activity of master copies was predicted by sequence analysis and confirmed by the presence of mRNA transcripts. Phylogenetic analysis of Ty3/gypsy-like LTR retrotransposons detected a new clade comprising CsRn1, Kabuki of Bombyx mori, and an uncharacterized element of Drosophila melanogaster. With its high repetitiveness and preserved mobile activity, it is proposed that CsRn1 may play a significant role in the genomic evolution of C. sinensis.
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Abstract
The Rho family GTPase Rac1 mediates a variety of signal transduction processes leading to activation of NADPH oxidase, actin cytoskeleton reorganization, transcription activation, and stimulation of DNA synthesis. In this study, Rac1 was found to form a reversible monomer and oligomer in both the GDP- and GTP-bound states in vitro and in cells. Mutational analysis and peptide competition experiments showed that the unique C-terminal domain of Rac1 consisting of six consecutive basic residues (amino acids 183-188) is required for the homophilic interaction. Oligomerization of Rac1-GTP led to a self-stimulatory GTPase-activating protein (GAP) activity, resulting in a significantly enhanced intrinsic GTP hydrolysis rate of Rac1-GTP. Deletion or mutation of the polybasic residues drastically decreased its intrinsic GTPase activity and resulted in a loss of the self-stimulatory GAP activity. In the oligomeric state, Rac1 became insensitive to the RhoGAP stimulation, albeit maintaining the responsiveness to the guanine nucleotide exchange factor. The ability of the Rac1 C-terminal mutants to activate the effector p21(cdc42/rac)-activated kinase-1 correlated with their oligomerization states, suggesting that oligomer formation potentiates effector activation. Furthermore, the oligomer-to-monomer transition of Rac1-GDP could be driven effectively by interaction with the Rho guanine nucleotide dissociation inhibitor. Building on previous characterizations of Rac1 interaction with regulatory proteins and effectors, these results suggest that Rac1 may employ yet another means of regulation by cycling between the monomeric and oligomeric states to effectively generate a transient and augmented signal.
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Association of the vitamin D receptor start codon polymorphism (FokI) with bone mineral density in postmenopausal Korean women. J Hum Genet 2001; 45:280-3. [PMID: 11043509 DOI: 10.1007/s100380070016] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We undertook this study in order to examine the association between bone mineral density (BMD) and a polymorphism at the first of two potential translation initiation codons in the vitamin D receptor (VDR) gene. This polymorphism was detected by restriction fragment length polymorphism analysis, using polymerase chain reaction (PCR) and the restriction endonuclease FokI. The f allele indicates the presence of the FokI site, and the F allele its absence. The FokI genotype was determined in 174 postmenopausal Korean women, aged 43-71 years. The distribution of FokI genotypes in Koreans was found not to differ significantly from those found in Caucasians and Japanese, although it does differ significantly from that found in the black American population. We observed a significant association between the FokI polymorphism and lumbar BMD; P = 0.048, analysis of covariance [ANCOVA], but no association with femoral neck BMD (P = 0.505, ANCOVA). Those with the ff genotype had a 13.3% lower BMD in the lumbar spine than the FF subjects. In addition, a significantly higher prevalence of the ff genotype was observed in osteoporotic compared with osteopenic or normal women (P = 0.036, chi2 test). These data suggest that the ff genotype of the VDR gene correlates with decreased BMD in the lumbar spine in postmenopausal Korean women.
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Carrier detection and prenatal diagnosis of hemophilia A in a Korean population by PCR-based analysis of the BclI/intron 18 and St14 VNTR polymorphisms. J Hum Genet 2000; 45:218-23. [PMID: 10944851 DOI: 10.1007/s100380070030] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
We have undertaken this study to identify the usefulness of polymerase chain reaction (PCR)-based analysis of DNA polymorphisms in the BclI/intron 18 and St14 variable number of tandem repeats (VNTR) loci for carrier detection and prenatal diagnosis of hemophilia A in the Korean population. We have analyzed these polymorphisms in members of 105 unrelated Korean families with severe hemophilia A. The observed heterozygosity rates for the BclI/intron 18 and St14 VNTR polymorphisms were 21.0% and 71.3%, respectively. The BclI/intron 18 polymorphism was less informative in Koreans when compared with Caucasians and Japanese. The allele frequencies for St14 VNTR in Koreans were different from those in Caucasians. Compared with Caucasians, there was a markedly higher occurrence of low molecular weight alleles in Koreans. The observed heterozygosity for the St14 VNTR polymorphism in combination with the BclI/intron 18 polymorphism was 81.9%. These two polymorphisms were applied to determine the carrier status of 107 women from 65 unrelated families, and to assess fetal status in 37 pregnancies. So far, we have experienced one case of misdiagnosis of carriership. Our study demonstrated that the PCR-based analysis of the BclI/intron 18 and St14 VNTR polymorphisms was useful in the carrier detection and prenatal diagnosis of hemophilia A in the Korean population.
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Abstract
RhoA organizes actin stress fibres and is necessary for cell transformation by oncogenes such as src and ras. Moreover, RhoA is implicated in cadherin clustering during the formation of adherens junctions. The catenin p120 has also been implicated in cadherin clustering through an unknown mechanism. Here we show that p120 selectively inhibits RhoA activity in vitro and in vivo. RhoA inhibition and the interaction of p120 with cadherins are mutually exclusive, suggesting a mechanism for regulating the recruitment and exchange of RhoA at nascent cell-cell contacts. By affecting RhoA activation, p120 could modulate cadherin functions, including suppression of invasion, neurite extension and junction formation.
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Insulin-like growth factors (IGFs), IGF-binding proteins (IGFBPs), and IGFBP-3 protease activity in the peritoneal fluid of patients with and without endometriosis. Fertil Steril 2000; 73:996-1000. [PMID: 10785227 DOI: 10.1016/s0015-0282(00)00493-3] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
OBJECTIVE To compare levels of insulin-like growth factor (IGF) components in the peritoneal fluid of patients with and without endometriosis. DESIGN Patients with endometriosis were compared with control patients. SETTING Seoul National University Hospital, Korea. PATIENT(S) Forty-three patients with endometriosis and 20 patients without endometriosis. INTERVENTION(S) Peritoneal fluid specimens were collected. MAIN OUTCOME MEASURE(S) Insulin-like growth factors, IGF binding protein (IGFBP) profiles and IGFBP-3 protease activity. RESULT(S) The IGF-I levels in peritoneal fluid were significantly higher in patients with endometriosis than in control patients, while the IGFBP-3 levels and the relative proportion of IGFBP-2 in peritoneal fluid were significantly lower in patients with endometriosis than in control patients. However, IGF-II levels, IGFBP-4 profiles, and IGFBP-3 protease activity did not differ significantly between the two groups. No correlation between these IGF components in peritoneal fluid and the stage of endometriosis was noted. CONCLUSION(S) The profiles of IGF components in peritoneal fluid of patients with pelvic endometriosis may play an important role in the growth of ectopic endometrium and endometriosis-induced infertility.
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Genetic deletion of the Pten tumor suppressor gene promotes cell motility by activation of Rac1 and Cdc42 GTPases. Curr Biol 2000; 10:401-4. [PMID: 10753747 DOI: 10.1016/s0960-9822(00)00417-6] [Citation(s) in RCA: 239] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Pten (Phosphatase and tensin homolog deleted on chromosome 10) is a recently identified tumor suppressor gene which is deleted or mutated in a variety of primary human cancers and in three cancer predisposition syndromes [1]. Pten regulates apoptosis and cell cycle progression through its phosphatase activity on phosphatidylinositol (PI) 3,4,5-trisphosphate (PI(3,4,5)P(3)), a product of PI 3-kinase [2-5]. Pten has also been implicated in controlling cell migration [6], but the exact mechanism is not very clear. Using the isogenic Pten(+/+) and Pten(-/-) mouse fibroblast lines, here we show that Pten deficiency led to increased cell motility. Reintroducing the wild-type Pten, but not the catalytically inactive Pten C124S or lipid-phosphatase-deficient Pten G129E mutant, reduced the enhanced cell motility of Pten-deficient cells. Moreover, phosphorylation of the focal adhesion kinase p125(FAK) was not changed in Pten(-/-) cells. Instead, significant increases in the endogenous activities of Rac1 and Cdc42, two small GTPases involved in regulating the actin cytoskeleton [7], were observed in Pten(-/-) cells. Overexpression of dominant-negative mutant forms of Rac1 and Cdc42 reversed the cell migration phenotype of Pten(-/-) cells. Thus, our studies suggest that Pten negatively controls cell motility through its lipid phosphatase activity by down-regulating Rac1 and Cdc42.
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Influence of female age on pregnancy outcome in in vitro fertilization and embryo transfer patients undergoing intracytoplasmic sperm injection. J Obstet Gynaecol Res 2000; 26:49-54. [PMID: 10761332 DOI: 10.1111/j.1447-0756.2000.tb01201.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
PURPOSE To determine the influence of female age on the outcomes of ICSI in IVF-ET patients. METHODS One hundred and seventy-five couples underwent 352 cycles of ICSI. The quality of oocytes and embryos, fertilization rate, and pregnancy outcomes were retrospectively evaluated according to female age; < 30 years in Group A (49 cycles), 30-34 in Group B (177 cycles), 35-39 in Group C (97 cycles), and > or = 40 in Group D (29 cycles). RESULTS The fertilization rates were not significantly different among the age groups. Significant negative linear correlations were observed between female age and the numbers of oocytes retrieved and embryos transferred, and cumulative embryo score. Clinical pregnancy rates were significantly decreased and spontaneous abortion rate increased with advancing age. CONCLUSIONS Female age may be a prognostic indicator in ICSI program.
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Abstract
PROBLEM The pathogenesis of uterine leiomyomata is still unclear. Recently it has been suggested that mac25 plays a tumor-suppressive role in various tumors. The aims of this study were to evaluate a possible involvement of mac25 in the growth of leiomyoma and in the mechanism of a gonadotropin-releasing hormone agonist (GnRHa) inducing shrinkage of leiomyoma. METHODS OF STUDY Mac25 mRNA transcript was measured by Northern blot in total RNA extracted from the paired specimens of leiomyoma and adjacent myometrium from untreated patients (n = 25) and from leiomyoma specimens from GnRHa-pretreated patients (n = 10). RESULTS Mac25 mRNA expression was significantly lower in large leiomyoma (more than 150 cm3 in volume) than in adjacent myometrium and small leiomyoma (less than 120 cm3 in volume) from untreated patients. There was no difference in this expression between the proliferative and secretory phases of the menstrual cycle. Leiomyoma from GnRHa-pretreated patients had mac25 gene expression levels similar to myometrium and small leiomyoma from untreated patients. CONCLUSIONS Mac25 may be involved in the growth of uterine leiomyoma and the action of GnRHa may, in part, be mediated by mac25.
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Abstract
Duplication of distal 15q results in a recognizable clinical phenotype. We report here on a 25-day-old boy with a de novo interstitial duplication of chromosome region 15q15-q24. The manifestations in this patient are milder than those of previously described patients and include minor facial anomalies, velopharyngeal insufficiency, branchial cleft cyst, and hydronephrosis. Fluorescence in situ hybridization (FISH) using a chromosome 15 painting probe confirmed that the extra material is of chromosome 15 origin. Further analysis with the SNRPN probe demonstrated that the duplication is telomeric to the Prader-Willi/Angelman syndrome critical region. This case delineates a broader spectrum for patients with duplication 15q syndrome.
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The outcome of sperm retrieval and intracytoplasmic sperm injection in patients with obstructive azoospermia: impact of previous tuberculous epididymitis. J Assist Reprod Genet 1999; 16:431-5. [PMID: 10478323 PMCID: PMC3455488 DOI: 10.1023/a:1020521625765] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
PURPOSE Our purpose was to investigate the influence of previous tuberculous epididymitis in patients with obstructive azoospermia on the outcome of sperm retrieval and intracytoplasmic sperm injection (ICSI). METHODS Eighty-eight cycles of ICSI were performed in 44 patients with obstructive azoospermia; 16 cycles (7 patients) with tuberculous obstructive azoospermia and 72 cycles (37 patients) with nontuberculous obstructive azoospermia. RESULTS The rates of fertilization and embryo cleavage were comparable, and there was no significant difference in the clinical pregnancy rate per fresh transfer between the two groups. The rates of embryo implantation and clinical miscarriage were also comparable. CONCLUSIONS Embryo quality and pregnancy outcome in sperm retrieval and ICSI were comparable in both the tuberculous and the nontuberculous obstructive azoospermia patients. Although there was a preponderance of testicular sperm used in the tuberculous obstructive azoospermia group, our results suggest that previous tuberculous epididymitis in patients with obstructive azoospermia does not affect the outcome of sperm retrieval and ICSI.
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The relationship among circulating insulin-like growth factor components, biochemical markers of bone turnover and bone mineral density in postmenopausal women under the age of 60. Clin Endocrinol (Oxf) 1999; 51:301-7. [PMID: 10469009 DOI: 10.1046/j.1365-2265.1999.00769.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVES The changes in circulating IGF components after the menopause and the potential role of new markers of bone turnover and circulating IGF components in predicting bone mass in postmenopausal women are still controversial and the relationship between these two systems has not been investigated. The aims of this study were to investigate the changes in circulating IGF components after the menopause, to evaluate whether new markers of bone turnover and circulating IGF components reflect bone mass in postmenopausal women under the age of 60 and to study the relationship between these two systems. DESIGN, PATIENTS AND MEASUREMENTS Serum IGF-I, IGF-II, IGFBP-1, IGFBP-2, IGFBP-3, osteocalcin (OST), bone specific alkaline phosphatase (BAP), urinary deoxypyridinoline (DPYD) and N-telopeptide of type I collagen (NTX) were measured in 31 premenopausal women aged 31-43 and 65 postmenopausal women aged 47-60: this latter group comprised 30 normal healthy women and 35 osteoporotic women. RESULTS Compared with premenopausal women or normal postmenopausal women, serum IGF-1 and IGFBP-3 levels were significantly lower in osteoporotic postmenopausal women while no significant differences in serum levels of IGF-II, IGFBP-1 and IGFBP-2 were observed. The correlations between bone turnover markers and circulating IGF components (except between serum BAP and IGF-II), and between bone turnover markers and bone mineral density (BMD) in postmenopausal women were not significant. However, serum IGF-I and IGFBP-3 correlated positively with BMD of the lumbar spine and/or Ward's triangle even if age, BMI and menopause duration were taken into account in a multiple regression analysis model. CONCLUSIONS Circulating IGF-I and IGFBP-3 may be involved in the mechanism of bone loss in postmenopausal women under the age of 60. They may also provide indirect information on the current bone microenvironment different from that provided by new markers of bone turnover.
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Abstract
To determine the frequency of chromosomal abnormalities in a child psychiatric population, and to evaluate possible associations between types of abnormalities and patient's clinical characteristics, cytogenetic examination was performed on 604 patients. Demographic data, reasons for karyotyping, clinical signs, and other patient characteristics were assessed and correlated with the results from karyotyping. Chromosomal abnormalities were found in 69 patients (11.3%); these were structural in 49 cases and numerical in 20. Inversion of chromosome nine was found in 15 subjects, trisomy of chromosome 21 in 11, and fragile X in five patients. When karyotyping was performed because of intellectual impairment or multiple developmental delay, significantly more abnormalities were found than average; when performed because autistic disorder was suspected, the number of abnormalities was significantly fewer. There were no differences in clinical variables between structural and numerical abnormalities, nor among nine types of chromosomal abnormalities, except that numerical abnormalities and polymorphism were found at a later age, and that walking was more delayed and IQ was lower in patients with Down syndrome. Clinicians should be aware of the possible presence of chromosomal abnormalities in child psychiatric populations; the close collaboration with geneticists and the use of more defined guidelines for cytogenetic investigation are important.
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Detection of aneuploidy for chromosomes 4, 6, 7, 8, 9, 10, 11, 12, 13, 17, 18, 21, X and Y by fluorescence in-situ hybridization in spermatozoa from nine patients with oligoasthenoteratozoospermia undergoing intracytoplasmic sperm injection. Hum Reprod 1999; 14:1266-73. [PMID: 10325276 DOI: 10.1093/humrep/14.5.1266] [Citation(s) in RCA: 161] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Recent evidence suggests that infertile males donating semen for intracytoplasmic sperm injection (ICSI) may be at an increased risk of transmitting numerical (predominantly sex chromosome) abnormalities to their offspring. The present study was designed to determine aneuploidy in spermatozoa from oligoasthenoteratozoospermic (OAT) patients undergoing ICSI. Aneuploidy frequencies of 12 autosomes and the sex chromosomes were determined by fluorescence in-situ hybridization (FISH) on spermatozoa from fresh ejaculate of nine severe OAT patients and four proven fertile donors. FISH, using directly labelled (fluorochrome-dUTP) satellite or contig DNA probes specific for chromosomes 4, 6, 7, 8, 9, 10, 11, 12, 13, 17, 18, 21, X, and Y, was performed on decondensed spermatozoa. Per chromosome disomy frequencies for autosomes and sex chomosomes in OAT males were 0-5. 4%. In contrast, the disomy frequencies in controls were 0.05-0.2%. The frequency of diploid spermatozoa in OAT patients was 0.4-9.6%; controls showed a mean of 0.04%. Using recently developed formulae, the total aneuploidy in our OAT patient population was estimated to be 33-74%. In contrast, estimates of mean total aneuploidy in the spermatozoa of controls ranged from 4.1 to 7.7%, depending upon method of calculation. Six series of ICSI were performed on five of the OAT patients. Four resulted in no establishment of pregnancy; the others failed to establish ongoing pregnancies. Our cytogenetic data show significantly elevated frequencies of diploidy, autosomal disomy and nullisomy, sex chromosome aneuploidy, and total aneuploidy in OAT patients, which may contribute to the patients' infertility.
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Abstract
OBJECTIVE To review and evaluate a series of patients who underwent microsurgical anastomosis of previously sterilized fallopian tubes. DESIGN Retrospective clinical study. SETTING Tertiary care academic center. PATIENT(S) In the 134-month span from January 1980 to February 1991, 1,118 women were evaluated for microsurgical reversal of previous tubal sterilization. MAIN OUTCOME MEASURE(S) Clinical characteristics of patients, pregnancy rates (PRs), and factors influencing the outcome. RESULT(S) Of 1,118 patients, 633 (56.6%) had been sterilized by laparoscopic cautery. Loss of children was a leading reason for requesting tubal reversal. The mean interval between tubal sterilization and reversal was 51.9 months. Nine hundred twenty-two (82.5%) patients were followed up for > 5 years. The overall PR after microsurgical tubal anastomosis was 54.8% (505 of 922) with a delivery rate of 72.5% (366 of 505), and the estimated anatomical success rate was 88.2% (814 of 922). There was no statistically significant difference in the PR or in the interval from tubal reversal to conception among the different operative procedure groups. In addition, no statistically significant difference in the PR was observed regardless of the postoperative tubal length. However, the interval from operation to pregnancy decreased significantly as the postoperative tubal length increased. The pregnant patients (n = 505) were younger and had a longer postoperative tube than the nonpregnant patients (n = 417); these differences were statistically significant. CONCLUSION(S) The pregnancy rate after microsurgical reversal of tubal sterilization was not significantly correlated with the method and duration of sterilization, the operative procedure, or the postoperative tubal length.
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Simultaneous program of natural-cycle in vitro fertilization and cryopreserved-thawed embryo transfer. J Assist Reprod Genet 1996; 13:716-21. [PMID: 8947820 DOI: 10.1007/bf02066425] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
PURPOSE This clinical study was designed to identify and compare the pregnancy rates of simultaneous program of natural-cycle IVF and cryopreserved-thawed ET (NICE) with those of natural-cycle IVF and cryopreserved-thawed ET. METHODS All three groups comprised spontaneously ovulating infertile women under the age of 40 and without any male factor present. The NICE program was performed in 36 patients (47 cycles) who had previously undergone IVF-ET resulting in cryopreserved embryos. As control groups, the natural-cycle IVF was performed in 45 patients (80 cycles), and the cryopreserved-thawed ET alone in 29 patients (40 cycles). RESULTS The cancellation rate of the initiated cycles prior to ET was 19.1% (9/47) in the NICE group, 23.8% (19/80) in the natural-cycle IVF group, and 2.5% (1/40) in the cryopreserved-thawed ET group. The mean number of embryos transferred was 4.0 +/- 1.1 (2-5) in the NICE group, 1.0 in the natural-cycle IVF group, and 4.2 +/- 1.8 (1-5) in the cryopreserved-thawed ET group. The clinical pregnancy rates per aspiration cycle (32.5%) and per ET cycle (34.2%) in the NICE group were significantly higher than those (14.9, 16.4%) in the natural-cycle IVF group. The clinical and delivered pregnancy rates per ET (34.2, 26.3%) in the NICE group were higher than those (20.5, 15.4%) in the cryopreserved-thawed ET group, without statistical significance. CONCLUSIONS Since the NICE program results in saving the fresh oocyte for patients participating in cryopreserved-thawed ET, more favorable pregnancy rates may be obtained from NICE cycles in women ovulating normally who had previously undergone IVF-ET with embryo cryopreservation.
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Phylogenetic relationships of annelids, molluscs, and arthropods evidenced from molecules and morphology. J Mol Evol 1996; 43:207-15. [PMID: 8703086 DOI: 10.1007/bf02338828] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Annelids and arthropods have long been considered each other's closest relatives, as evidenced by similarities in their segmented body plans. An alternative view, more recently advocated by investigators who have examined partial 18S ribosomal RNA data, proposes that annelids, molluscs, and certain other minor phyla with trochophore larva stages share a more recent common ancestor with one another than any do with arthropods. The two hypotheses are mutually exclusive in explaining spiralian relationships. Cladistic analysis of morphological data does not reveal phylogentic relationships among major spiralian taxa but does suggest monophyly for both the annelids and molluscs. Distance and maximum-likelihood analyses of 18S rRNA gene sequences from major spiralian taxa suggest a sister relationship between annelids and molluscs and provide a clear resolution within the major groups of the spiralians. The parsimonious tree based on molecular data, however, indicates a sister relationship of the Annelida and Bivalvia, and an earlier divergence of the Gastropoda than the Annelida-Bivalvia clade. To test further hypotheses on the phylogenetic relationships among annelids, molluscs, and arthropods, and the ingroup relationships within the major spiralian taxa, we combine the molecular and morphological data sets and subject the combined data matrix to parsimony analysis. The resulting tree suggests that the molluscs and annelids form a monophyletic lineage and unites the molluscan taxa to a monophyletic group. Therefore, the result supports the Eutrochozoa hypothesis and the monophyly of molluscs, and indicates early acquisition of segmented body plans in arthropods.
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Abstract
OBJECTIVE To summarize the procedures and outcomes of assisted reproductive technology (ART) initiated in Asia-Oceanic region in 1992 and 1993. DESIGN Data were collected on an annual summary form and submitted to the Reproductive Biology Committee of AOFOG. PARTICIPANTS Twelve member countries of AOFOG submitted data on ART procedures performed in 1992 and 1993-Australia, Egypt, Hong Kong, India, Indonesia, Japan, Korea, New Zealand, Pakistan, Singapore, Taiwan, and Thailand. Data were collected in 1995 so that the outcomes of all pregnancies established would be known. MAIN OUTCOME MEASURES Clinical characteristics of patients, causes of infertility, protocols and outcomes of controlled ovarian hyperstimulation (COH), and outcomes of clinical pregnancy including abortion, ectopic pregnancy, multiple pregnancy, and congenital malformation were measured in each ART procedure. RESULTS In 1992, 23,872 cycles of IVF-ET were performed with 21.8% clinical pregnancy rate (PR) per ET, 4,840 cycles of GIFT with 29.5% PR per transfer, 1,136 cycles of simultaneous IVF-ET and GIFT with 29.9% PR, and 1,563 cycles of ZIFT with 23.1% PR. Total 575 clinical pregnancies were achieved in cryopreserved ET program, 96 pregnancies in oocyte donation program, and 87 pregnancies in microassisted fertilization (MAF) program. In 1993, 24,571 cycles of IVF-ET were performed with 21.6% clinical PR per ET, 5,240 cycles of GIFT with 28.2% PR per transfer, 1,063 cycles of simultaneous IVF-ET and GIFT with 32.0% PR, 1,005 cycles of ZIFT with 21.6% PR, 5,562 cycles of cryopreserved ET program with 12.8% PR, and 2,198 cycles of MAF program with 11.6% PR. Total 117 clinical pregnancies were achieved in oocyte donation program. CONCLUSIONS Although the concepts as well as the status and results of ART are continuously changing, this report may be helpful in planning the future of ART in Asia-Oceania by analyzing the past history.
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Detection of antiendometrial antibodies in sera of patients with endometriosis by dual-colored, double-labeling immunohistochemical method and western blot. Am J Reprod Immunol 1995; 34:80-7. [PMID: 8526993 DOI: 10.1111/j.1600-0897.1995.tb00922.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
PROBLEM This study was undertaken to determine whether specific binding activities against endometrial proteins in sera of patients with endometriosis are detectable and, if so, to identify endometrial antigens involved in autoimmunity in endometriosis. METHOD Sera from 33 patients with endometriosis and 20 cord sera (controls) were tested against endometria of patients and their protein extracts by dual-colored, double-labeling immunohistochemical method, and Western blotting. RESULTS Antiendometrial binding activities were detected in sera of 2 (10.0%) control patients and 13 (48.2%) patients with endometriosis by the immunohistochemical method. Endogenous immunoglobulin G (IgG) binding to endometrial proteins had molecular weights (MW) of 26, 28, 54, 85, 107 and 116 kDa. Most sera of both control and patients showed reactivity against endometrial proteins with MW of 34, 36, 56 and 77 kDa. However, there were specific IgG autoantibodies reactive against the endometrial proteins of 71, 92, and 103 kDa in sera of 55.2% (16/29) of patients but not in the control sera. Over 80% (10/12) of patients' sera with binding activities detectable by the immunohistochemical method also tested positive by Western blot analysis. CONCLUSIONS These data show that specific IgG antibodies reactive against endometrial antigens are detectable in sera from some patients with endometriosis.
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Abstract
Premature ovarian failure (POF) may be caused by a variety of factors that result in the depletion of responsive ovarian follicles. There is a increasing body of evidence that suggests an autoimmune etiology in some POF patients. Data in support of an autoimmune etiology include: (1) lymphocytic and plasma cell infiltration of the ovary and alteration of T cell subsets; (2) circulating autoantibodies to ovarian antigens; (3) association with other "autoimmune" disorders; (4) recovery of ovarian function after regression of autoimmune status. The mechanism for ovarian autoimmunity is unknown. Genetic or environmental factor might be involved in the stimuli inducing immune response. The possibility that major histocompatibility complex antigen and cytokines are implicated in human autoimmune POF has been proposed. The relative contribution of cell-mediated immunity and antibody-mediated immunity remains obscure in animal models and in POF patients. Currently, in vitro fertilization and/or gamete intrafallopian transfer with donated oocytes are the best therapeutic options to achieve pregnancy although ovulation induction and immunosuppressive treatment might be used in approved experimental protocols. A newly developed double bridged enzyme linked immunosorbent assay (ELISA) might be useful in screening POF patients to identify those for whom temporary treatments may improve fertility.
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Cloning and characterization of the gene encoding an extracellular alkaline serine protease from Vibrio metschnikovii strain RH530. Gene 1995; 152:59-63. [PMID: 7828929 DOI: 10.1016/0378-1119(94)00648-c] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The gene vapF, encoding VapT, one of the extracellular sodium dodecyl sulfate (SDS)-resistant alkaline serine proteases (Serp) from the Gram- Vibrio metschnikovii strain RH530 has been cloned in Escherichia coli. The recombinant E. coli produced a protease which co-migrated with VapT on gelatin polyacrylamide gels. The nucleotide (nt) sequence of the cloned vapT revealed a single open reading frame of 1641 bp encoding 547 amino acids (aa) (58,961 Da). Upon analysis of the N-terminal aa sequence, VapT was shown to be processed properly in recombinant E. coli and to consist of 428 aa (45,626 Da). The deduced aa sequence of VapT showed significant sequence homology to subtilisin Carlsberg from Bacillus licheniformis, particularly in the regions containing active site residues and calcium-binding sites. VapT had an intervening region of approx. 149 aa between the His and Ser residues of the active site, as compared with other Serp.
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The present status of assisted reproductive technology in Asia-Oceania. ASIA-OCEANIA JOURNAL OF OBSTETRICS AND GYNAECOLOGY 1994; 20:331-44. [PMID: 7832663 DOI: 10.1111/j.1447-0756.1994.tb00478.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
This is a survey on the present status of assisted reproductive technology in the Asia-Oceanic region. The survey formats were sent to the 19-member societies of AOFOG. By the end of August 1991, 11 countries responded: Australia, Egypt, Hong Kong, Israel, Japan, Malaysia, New Zealand, Philippines, Republic of China, Singapore and Thailand. This report is a summary of data from 12 countries including Korea. It comprised of 14 headings: IVF, GIFT, AIH, AID, donor sperm in ART, donor eggs in ART, preembryos from IVF for donation, cryopreservation of eggs, cryopreservation of fertilized eggs and preembryos, research of preembryos, surrogate mothers, additional procedures, quality assurance in reproductive technology and formation of policy for emerging reproductive technology. Each heading is composed of status of regulations, cost and coverage and the results and management of program.
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Sequence of the 18S ribosomal RNA-encoding gene of the crustacean Philyra pisum: longer sequences of decapods in the V9 region. Gene 1994; 149:379-80. [PMID: 7959023 DOI: 10.1016/0378-1119(94)90182-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The complete sequence of the 18S rRNA gene of Philyra pisum was determined by using PCR cloning and Taq sequencing. The sequence was compared with those known from other crustaceans. The decapods (Oedignathus inermis, Pugettia quadridens, Philyra pisum) were distinguished from the other crustaceans (Artemia salina, Bosmina longirostris, Diastylis sp.) by longer sequences (17-41 bp) in the V9 region.
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Abstract
The fragile X syndrome is a common X-linked mental retardation and autism, affecting females as well as males. The fragile site X chromosomes were studied in a series of 153 mentally retarded boys of unknown etiology to determine the frequency of fragile X syndrome, and to assess the feasibility of making a clinical diagnosis of the fragile X syndrome in young boys before cytogenetic results were known. The 10 boys (6.4%) were positive for fra (X) (q27). The phenotype of fra (X) (q27) positive patients were typical except one who also had sex chromosomal mosaicism. There were three pairs of siblings among the fra (X) (q27) positive patients. Frequency of expression of the fragile site was in 10 to 47 per cent of cells. In addition, 19 boys showed a previously unsuspected chromosomal abnormality. The frequency of the fragile X syndrome in the present study is not significantly different from those in Caucasians and Japanese population. The fragile X syndrome can be recognized by noting key aspects of family history as well as the clinical features in mentally retarded boys.
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The efficacy of a combination administration of gonadotropin-releasing hormone agonist and gonadotropins for controlled ovarian hyperstimulation in IVF program. ASIA-OCEANIA JOURNAL OF OBSTETRICS AND GYNAECOLOGY 1990; 16:337-45. [PMID: 2129188 DOI: 10.1111/j.1447-0756.1990.tb00358.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
In 105 patients with the past history of poor response to the previous controlled ovarian hyperstimulation (COH) due to poor follicular growth or premature LH surge, the efficacy of pituitary suppression with gonadotropin-releasing hormone agonist (GnRHa) in IVF/GIFT program was evaluated in 112 cycles of COH using a combination regimen of leuprolide acetate (Lupron) and FSH/hMG or pure FSH from May to December, 1989. After suppression phase, serum E2 and progesterone levels decreased significantly, but there was no change in serum LH and FSH levels. There was no occurrence of premature LH surge during COH. Eleven cycles (9.8%) were cancelled, and 3 cycles (3.0%) failed in the transvaginal oocytes retrieval. The 7.00 +/- 3.32 follicles (FD greater than or equal to 12 mm) were observed, and 6.11 +/- 4.15 oocytes were retrieved. The 3.59 +/- 2.57 oocytes were fertilized and cleaved with the cleavage rate of 55.7%. In 83 IVF patients, 4.08 +/- 2.39 embryos were transferred, and 16 pregnancies were obtained with the pregnancy rate per ET of 19.3%. In 6 GIFT patients, 7.83 +/- 3.31 oocytes were available for transfer. When compared with the previous 108 cycles, the cancellation rate during COH was decreased and all the parameters of the outcome of COH including the pregnancy rate were increased. These data suggest that GnRHa therapy for pituitary suppression is an effective adjunct to the current gonadotropin regimens for COH in IVF/GIFT and can increase the probability of oocytes retrieval and pregnancy, especially in the previous poor responders.
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Oocyte donation program using a simplified hormonal regimen. ASIA-OCEANIA JOURNAL OF OBSTETRICS AND GYNAECOLOGY 1990; 16:181-90. [PMID: 2128445 DOI: 10.1111/j.1447-0756.1990.tb00224.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
It has been well recognized that both the synchronization of luteinizing hormone (LH) surge between the donor and the recipient for normally cycling women and the complex steroid replacement regimen given on a sequential and incremental basis for women with primary or secondary ovarian failure are two important aspects in oocyte donation. In oocyte donation program at SNUH, a simplified hormonal regimen applicable both to normally cycling women and to those with ovarian failure which consisted of administering 2 mg estradiol (E2) valerate orally 3 times a day augmented with 100 mg progesterone (P) in oil intramuscularly daily starting on the day preceding the oocyte retrieval from the donor was utilized. From July 1988 to December 1989 at SNUH, 11 cycles of oocyte donation program in 10 infertile patients were undertaken and 5 patients succeeded in pregnancy.
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Abstract
The sperm penetration assay is an expensive, time-consuming test to assess male fertility in vitro. Although some investigators are enthusiastic in its application, others feel that it is not sensitive or specific enough to be used as part of the routine infertility evaluation. Indeed, this bioassay is not a faithful reproduction of in vivo conditions. However, if the SPA is abnormal, it is unlikely that sperm will fertilize a human ovum in vivo. Conversely, a normal SPA does not guarantee successful in vivo fertilization. No bioassay can be absolute in its predictive value, but false-negative results must be kept to a minimum for this bioassay to be of any clinical significance. Each laboratory performing the SPA should optimize the assay for sensitivity, reproducibility, and minimization of false-negative results and then establish normal and abnormal ranges of its own. If the limitations of the SPA are kept in mind, and if we employ it very selectively, it may still be useful.
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Implantation potential of each pre-embryo in multiple pregnancies obtained by in vitro fertilization seems to be different. Int J Gynaecol Obstet 1989. [DOI: 10.1016/0020-7292(89)90291-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Implantation potential of each pre-embryo in multiple pregnancies obtained by in vitro fertilization seems to be different. Fertil Steril 1988; 50:906-11. [PMID: 3203754 DOI: 10.1016/s0015-0282(16)60370-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Endometrial receptivity and pre-embryo quality are the main factors determining embryo implantation in in vitro fertilization. If one embryo implants normally and goes to term, the endometrium can be assumed to be normal. Eighty-one patients (March 1981 to 1987) had transfers of multiple pre-embryos, resulting in multiple pregnancies with at least one reaching term. The number of gestational sacs at 8 to 12 weeks of pregnancy, at 20 weeks, and the number of term pregnancies were studied longitudinally. Twelve patients (14.8%) had 2 pre-embryos transferred, 19 (23.5%) had 3, 21 (25.9%) had 4, 17 (21.0%) had 5, 9 (11.1%) had 6, and 3 (3.7%) had 7. At 20 weeks 18 patients (22.2%) had a single viable fetus, 56 (69.1%) had twins, 6 (7.4%) had triplets, and 1 (1.2%) had quadruplets. A total of 325 pre-embryos were transferred; 178 gestational sacs were observed at 8 to 12 weeks, but only 153 showed fetal heartbeat. Total embryo loss at 8 to 12 weeks was 53.0%; when the "index" embryo was excluded, it reached 61%. Regardless of the number of pre-embryos transferred, only 2.2 embryos on average were able to establish a normal pregnancy. (A)synchronism of the pre-embryos did not affect outcome. Results suggest that with normal endometrial receptivity, the implantation potential of each pre-embryo is different.
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Maturity and in vitro fertilization of superovulated human oocytes in relation to various hormone levels in follicular fluids. ASIA-OCEANIA JOURNAL OF OBSTETRICS AND GYNAECOLOGY 1988; 14:259-65. [PMID: 3214348 DOI: 10.1111/j.1447-0756.1988.tb00102.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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Plasma prolactin and dehydroepiandrosterone sulfate levels in polycystic ovarian disease. ASIA-OCEANIA JOURNAL OF OBSTETRICS AND GYNAECOLOGY 1987; 13:215-20. [PMID: 2957985 DOI: 10.1111/j.1447-0756.1987.tb00253.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Diagnostic laparoscopy in gynecologic disorders. ASIA-OCEANIA JOURNAL OF OBSTETRICS AND GYNAECOLOGY 1987; 13:29-34. [PMID: 2954525 DOI: 10.1111/j.1447-0756.1987.tb00004.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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A computer program for survival comparisons to a standard population. COMPUTER PROGRAMS IN BIOMEDICINE 1979; 10:91-104. [PMID: 487785 DOI: 10.1016/0010-468x(79)90056-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
PROPHAZ is a computer program created for the analysis of survival data using the general proportional hazards model. It was designed specifically for the situation in which the underlying hazard function may be estimated from the mortality experience of a large reference population, but may be used for other problems as well. Input for the program includes the variables of interest as well as the information necessary for estimating the hazard function (demographic and mortality data). Regression coefficients for the variables of interest are obtained iteratively using the Newton-Raphson method. Utilizing large sample asymptotic theory, x2 statistics are derived which may be used to test hypotheses of the form C beta = 0. Input format is completely flexible for the variables of interest as well as the mortality data.
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