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Biomedical subjects

A Romo

Publications and source records attributed to A Romo.

At least 19 recordsLinked to original sources
PubMed2004

Study of genetic expression of intrauterine growth factors IGF-I and EGFR in placental tissue from pregnancies with intrauterine growth retardation.

To investigate the possibility of altered gene expression of growth factors in prenatal growth retardation, we assessed expression of the genes for insulin-like growth factor-I (IGF-I) and epidermal growth factor receptor (EGFR) by RT-PCR from human placentas at term delivery in two groups: appropriate for gestational age (AGA) and pregnancies complicated with IUGR. The placentas from IUGR gestations showed reduced IGF-I expression with a significance of p = 0.008, whereas we did not find any significant differences in EGFR gene expression.

ErbB Receptors↗
PubMed2004

Intrauterine growth retardation: study of placental apoptosis.

We studied the rate of apoptosis in the placental tissue of pregnancies complicated with intrauterine growth retardation (IUGR) and compared it with the results obtained in normal placentas. Our results clearly demonstrate a strongly increased rate of apoptosis in placentas of children born with IUGR, suggesting severe placental dysfunction. The significance of these findings needs further study.

Apoptosis↗
PubMed1997

[Left superior vena cava drainage to the coronary sinus. Fetal cardiac doppler].

We report a fetus of 35 weeks gestation in which a continuous flow was detected in the lower portion of the right atrium with a peak velocity of 0.8 m/s. After delivery the echo-doppler study showed a dilated coronary sinus in the long axis parasternal view, and a bilateral superior vena cava in the short axis suprasternal notch view. Comments about the cause of this anomalous continuous flow are discussed.

Echocardiography, Doppler↗
PubMed1996

Adenovirus replication is coupled with the dynamic properties of the PML nuclear structure.

Wild-type PML and at least four other novel proteins are localized within discrete nuclear structures known as PODs. We demonstrate here that during adenovirus infection, immediate early viral proteins from the E1 and E4 transcription units associate with the POD, which in turn undergoes a dramatic morphological change. During this process, the auto-antigen Sp-100 and NDP55 but not PML, relocate from the POD to the viral inclusion bodies, the sites of adenovirus DNA replication and late RNA transcription. The E4-ORF3 11-kD protein alone will induce this reorganization and reciprocally, viruses carrying mutations in the E4-domain fail to do so. These same viral mutants are defective in viral replication as well as the accumulation of late viral mRNAs and host cell transcription shutoff. We show that interferon (INF) treatment enhances the expression of PML, reduces or blocks PODs reorganization, and inhibits BrdU incorporation into viral inclusion bodies. In addition, cell lines engineered to overexpress PML prevent PODs from viral-induced reorganization and block or severely delay adenovirus replication. These results suggest that viral replication relies on components of the POD and that the structure is a target of early viral proteins.

Adenovirus E1 Proteins↗
PubMed1995

Interactions between the retinoid X receptor and a conserved region of the TATA-binding protein mediate hormone-dependent transactivation.

The retinoid X receptor (RXR) participates in a wide array of hormonal signaling pathways, either as a homodimer or as a heterodimer, with other members of the steroid and thyroid hormone receptor superfamily. In this report the ligand-dependent transactivation function of RXR has been characterized, and the ability of RXR to interact with components of the basal transcription machinery has been examined. In vivo and in vitro experiments indicate the RXR ligand-binding domain makes a direct, specific, and ligand-dependent contact with a highly conserved region of the TATA-binding protein. The ability of mutations that reduce ligand-dependent transcription by RXR to disrupt the RXR-TATA-binding protein interaction in vivo and in vitro suggests that RXR makes direct contact with the basal transcription machinery to achieve activation.

DNA-Binding Proteins↗
PubMed1994

Yeast artificial chromosome cloning of 3.2 megabases within chromosomal band 11q24 closely linking c-ets 1 and Fli-1 and encompassing the Ewing sarcoma breakpoint.

Human chromosome 11 harbors many genes of medical significance and cancer-related rearrangements. The availability of cloned DNA in cosmids and in yeast artificial chromosomes (YACs), combined with fluorescence in situ hybridization analysis, has led to the cloning of genes at sites of chromosomal breakpoints in acute leukemias in 11q23 and in Ewing tumors in 11q24. YAC cloning has facilitated the construction of contigs covering large portions of chromosomes for the detailed analysis of disease gene regions. Here we have cloned in YACs approximately 3.2 Mb of DNA within band 11q24, spanning the Ewing sarcoma breakpoint. Landmark cosmids 23.2 (D11S374) and 5.8 (D11S372), shown by FISH to flank the breakpoint within a 1.5- to 1.8-Mb segment, were used to seed two YAC "walks" both centromeric and telomeric to the breakpoint by YAC-end cloning and screening of two total genomic YAC libraries. The centromeric YAC contig, which consists of 23 overlapping YACs and orders 19 sequence-tagged sites (STSs), covers a minimum of 2.2 Mb and spans the Ewing sarcoma breakpoint. c-ets 1 and Fli-1, two members of the ets family, have been linked within 400 kb of intervening DNA within this contig, which also comprises a polymorphic microsatellite, D11S912 (CA)n, which we have localized within the Fli-1 gene. The telomeric YAC contig, which consists of 11 overlapping YACs, comprises 5 STSs and covers a minimum of 1 Mb distal to the breakpoint. Taken together, the two contigs, which consist of a total of 34 YACs and comprise 24 STSs, are separated by a maximum gap of 200-400 kb and cover as a whole 3.2 Mb of DNA. This represents about 70% of human chromosomal band 11q24, which extends over approximately 4.4 Mb of DNA.

Base Sequence↗
PubMed1994

Cloning of the entire FLI1 gene, disrupted by the Ewing's sarcoma translocation breakpoint on 11q24, in a yeast artificial chromosome.

FLI1 (Friend leukemia virus integration 1), a member of the Ets gene family, is disrupted on 11q24 by the Ewing's Sarcoma (ES) and Peripheral Neuroepithelioma (PNE) t(11;22)(q24;q12) translocation. ES and PNE are Primitive Neuroectodermal Tumors (PNETs) and the consistent translocation t(11;22)(q24;q12) can be used for differential diagnosis. In PNETs the 3' part of human FLI1 is translocated from 11q24 to 22q12, where it is juxtaposed to the 5' end of the Ewing's Sarcoma gene (EWS). A fusion transcript, resulting in a chimeric protein, is generated. Here, we present the isolation and detailed characterization of a 250-kb colinear YAC, B45C11, which encompasses the ES and PNE breakpoint on 11q24, as shown by FISSH on ES and PNE chromosomes and interphase nuclei. This YAC represents a new reagent for potential use in rapid differential diagnosis by FISSH on tumor biopsies and on paraffin embedded samples, particularly when DNA and/or RNA are not available for molecular analysis. YAC B45C11, which spans 250 kb of contiguous DNA around the ES and PNE breakpoint, contains the entire FLI1 gene. Three potential HpaII-tiny-fragment (HTF) islands are revealed within the YAC. One of these islands appears to be associated with the 5' end of FLI1, which extends over approximately 120 kb of DNA on 11q24. In addition, we demonstrate that YAC B45C11 contains other transcribed sequences in addition to FLI1, by "cross-species" Northern blot hybridizations, which suggests the presence of additional genes in the immediate vicinity of the ES breakpoint on 11q24.

Base Sequence↗
PubMed1994

Large-scale screening of yeast artificial chromosome libraries using PCR.

The construction of physical maps of the human genome using sequence-tagged site content mapping requires that thousands of PCR amplifications be performed. On this scale, measures to reduce cost and to increase throughput become serious considerations. We describe relatively simple measures developed in our laboratory that increase the rate at which these reactions can be performed in a cost-effective manner. These measures have been extensively tested in our laboratory and are readily applicable in other laboratories including those performing library screening on a more modest scale.

Chromosome Mapping↗
PubMed1993

Chromosomal structure and expression of the human OTF1 locus encoding the Oct-1 protein.

The genomic structure of the POU domain containing oct-1 gene (OTF1 locus) coding region has been determined using human DNA recombinant bacteriophage and a yeast artificial chromosome clone. The gene is encoded by 16 exons spanning over 150 kb, and the Oct-1 protein reading frame has been extended to 766 amino acids. The exonic structure has been compared to the mouse Oct-2 protein and reveals a conservation of exon-intron boundaries as well as protein sequence similarity. To provide insight into Oct-1 control of transcriptional regulation during the cell-cycle the expression of the oct-1 gene was examined during cellular DNA replication and shows that the steady-state level of the oct-1 mRNA is not S-phase regulated.

Amino Acid Sequence↗
PubMed1992

Detection and characterization of "chimeric" yeast artificial chromosome clones by fluorescent in situ suppression hybridization.

"Chimeric" yeast artificial chromosomes (YACs) are clones containing two or more noncontiguous segments of DNA and represent the most common artifact found in total genomic YAC libraries currently used for large-scale genome mapping. These YACs create spurious mapping information that complicates the construction of YAC contigs and leads to erroneous maps during chromosome walks. The presence of these artifactual clones necessitates laborious and time-consuming characterization of each isolated YAC clone, either by comparison of the physical map of the YAC with the corresponding source genomic DNA, or by demonstrating discrepant chromosomal origins for the two ends of the YAC by hybridization or polymerase chain reaction (PCR). Here, we describe a rapid and sensitive method for the assessment of YAC colinearity by fluorescence in situ suppression hybridization (FISSH) by utilizing fluorescein-12-dUTP for labeling YAC clones. We have analyzed 51 YACs and found that 43% (22 out of 51) are chimeric and significantly larger (302 kb) than colinear ones (228 kb). One of the 51 YAC clones (2%) examined contains portions of three chromosomes and 2 (4%) seem to map to a chromosome different than that of the identifying STS. FISSH analysis offers a straightforward visualization of the entire YAC insert on the chromosomes and can be used to examine many YACs simultaneously in few days.

Artifacts↗
PubMed1988

Altered pulsatile pattern of luteinizing hormone in men with idiopathic normogonadotropic oligospermia.

Gonadotropin serum levels and pulsatile secretion of gonadotropin-releasing hormone (GnRH) and luteinizing hormone (LH) are regulated by sexual steroids and perhaps inhibin, but the relative rates of LH and follicle-stimulating hormone (FSH) secretion are modulated by the frequency of GnRH pulses. This study evaluated LH pulsatility in patients with idiopathic normogonadotropic oligospermia (INO) and normal men before and after clomiphene citrate (CC) administration. INO patients evidenced a lower mean LH levels (P less than 0.001), a higher mean pulse frequency (P less than 0.05) and similar pulse amplitude than normal men. CC induced in normal men a higher LH and testosterone (T) increments and increased pulse amplitude only in normal men. Estradiol (E2) showed no difference in either group. Patients with INO might evidence a hypothalamic disorder that may alter pulsatile GnRH secretion. A different response to CC in patients with INO seems to lend support to a primary hypothalamic lesion. A probable gonadotropin imbalance might alter intratesticular concentrations of T and E2 and be the cause of spermatogenic failure.

Adult↗
PubMedDate not supplied

Action of 2'-deoxycoformycin on mitogen-induced lymphoproliferation in the neonatal period.

The effect of 2'deoxycoformycin (dCF), a potent inhibitor of adenosine deaminase (ADA), on the proliferation of mononuclear cells from cord blood and from healthy controls as a response to the two mitogenic agents PHA and ConA was studied. The addition of dCF simultaneously with the mitogen did not modify cell proliferation either in neonates or in controls. Added 20 min before the mitogens, dCF induced in adults lymphocytes a significant inhibition in the response to PHA (68.11 +/- 10.40% of response in control cultures) and to ConA (58.78 +/- 26.23%). By contrast, in the neonatal period it induced a stimulatory effect on this response, both when PHA (117.64 +/- 26.48% of basal response) and ConA (108.18 +/- 21.72%) were employed. The possibility is discussed that this different function in lymphocyte behaviour in the newborn might contribute to the immunologic abnormality which children affected with ADA deficiency may exhibit at this age and also to the delay in the onset of clinical manifestations of immunodeficiency due to the defect in this enzyme.

Adenosine Deaminase Inhibitors↗