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Biomedical subjects

I Ariel

Publications and source records attributed to I Ariel.

At least 55 records · Page 3Linked to original sources
PubMed1994

Expression of the imprinted gene H19 in the human fetus.

The H19 gene is a parenterally imprinted maternally expressed gene which has a pivotal role in embryogenesis and fetal development. It is tightly linked to the IGF-II gene on chromosome 11p15.5 which is reciprocally imprinted. We studied the expression of the human H19 by in situ hybridization in an embryo 35 days post coitus (dpc) and in a fetus from the second trimester of pregnancy. The expression pattern of H19 in the human fetal tissues was similar to its expression in the mouse, and paralleled, with some exceptions, the expression of IGF-II in human fetuses. Abundant expression was found in organs comprising the fetoplacental unit: the placenta, the fetal adrenal, and liver. The expression in the fetal adrenal cortex was most prominent in the definitive cortex and somewhat weaker in the fetal zone. Considerable expression of H19 was found in the fetal liver as early as 35 dpc and in the second trimester. Hematopoietic cells in fetal liver did not express the gene. Moderate expression of H19 was detected in the epithelium of the small intestines, in endometrial stroma and Fallopian tube. In the kidney conspicuous labeling of the metanephric blastema was noted, which was markedly reduced with differentiation to tubules. This pattern of expression is identical to that of IGF-II in the fetal kidney and is relevant to the evolution of Wilms' tumor. No expression of H19 was found in the neural tube of the first trimester embryo or in the developing fetal brain in the second trimester, nor were transcripts detected in the choroid plexus.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Glands↗
PubMed1994

Monosomy 8q: prenatal diagnosis and autopsy findings.

The autopsy findings of a fetus with deletion of the long arm of chromosome 8 are described. Many of the features are similar to those of the tricho-rhino-phalangeal syndromes, types I and II, which are associated with deletions on chromosome 8q24. Other findings in this case, such as total absence of the corpus callosum and intestinal malrotation, have not been described in these syndromes. Genes involved in the development of the latter malformations may reside in adjacent regions on the long arm of chromosome 8. An elevated serum level of beta human chorionic gonadotropin (beta hCG) was found during pregnancy. This aberration should be included with other chromosomal disorders which may be detected by this test.

Abortion, Induced↗
PubMed1994

Relaxation of imprinting in trophoblastic disease.

Genomic imprinting--the uniparental-dependent transmittance of a genetic trait--has been accepted in recent years as a major mechanism in mammalian genetics. We studied the expression of the H19 gene, a parentally imprinted (maternally expressed) gene, by in situ hybridization in human placenta and trophoblastic disease. Expression was found to be abundant, in a decreasing order, in the intermediate trophoblast (villous and interstitial), the cytotrophoblast, and the syncytiotrophoblast. The villous stroma was also prominently labeled. Partial hydatidiform mole showed a similar pattern of expression as normal placenta. As expected, complete hydatidiform mole, whose genome consists of two haploid sets of paternal origin, was not labeled in the villous stroma and surrounding trophoblastic layer. However, some of the large mononuclear cells in the proliferating groups sprouting from the villous surface were strongly labeled. Prominent expression of H19 was found in placental site trophoblastic tumor and gestational choriocarcinoma. The phenomenon of emergence of expression of alleles subject to repression according to their gamete of origin is termed relaxation of imprinting, and is considered to be relevant to tumorigenesis. We suggest that the expression of the maternally expressed H19 gene in the androgenetic tissue of complete hydatidiform mole represents relaxation of imprinting and may be associated with its malignant potential.

Choriocarcinoma↗
PubMed1994

On the oncodevelopmental role of human imprinted genes.

Genome imprinting has an essential role in normal embryonal mammalian development. Starting early in differentiation, the transcripts of certain human genes, e.g. the paternally-H19 and the maternally-imprinted IGF2, are expressed in specific tissues and organs during fetal life. In several malignant disorders, imprinted genes are, again, unfolded. Characteristically, expression follows the same tissue presentation as during embryogenesis. Clinical paternal disomies, i.e. trophoblastic diseases, and their maternal counterpart, i.e. ovarian teratomas, are associated with apparent relaxation of imprinting once they turn malignant. Paediatric neoplasms, like Wilm's tumor (WT) and rhabdomyosarcoma, often express IGF2 and H19. Recently, we have found H19 expression in invasive urothelial cancer. Evidently, imprinted genes display an oncodevelopmental mode of expression, very much like the classical oncofetal proteins AFP and CEA. Based on available data, including tumor preferential paternal allele retention and chromosome 11 short arm physical linkage with oncogenes like H-ras, we hypothesize that imprinted genes not only accompany cancer but may play a causative role as well.

Antigens, Neoplasm↗
PubMed1994

Germ cell tumors of the ovary arising after dermoid cyst resection: a long-term follow-up study.

OBJECTIVE: To study the long-term ovarian neoplastic consequences of resection of a dermoid cyst. METHODS: The study population comprised 99 patients who were operated on for an ovarian dermoid cyst. Follow-up information was obtained for 91 women for a mean period of 5.06 +/- 2.46 years. RESULTS: Of the 99 women, 18 had bilateral dermoid cysts. Multiple dermoid cysts in a single ovary were found in nine of the women with bilateral cysts and in one of the remaining patients. Two patients developed malignant germ cell tumors, and three developed a recurrent dermoid cyst in an ovary from which a dermoid cyst had previously been extracted. Bilateral or multiple ovarian dermoid cysts were present at the initial operation in four (80%) of these patients. CONCLUSIONS: Women with bilateral or multiple dermoid cysts may include a subgroup of patients with a greater tendency to develop future ovarian germ cell neoplasms.

Adult↗
PubMed1994

Human imprinted genes as oncodevelopmental markers.

Imprinted genes mediate unique maternal or paternal genetic roles and their function is essential in prenatal development. The reciprocally imprinted human insulin-like growth factor 2 (IGF2) and H19 genes are expressed during embryonal life, also in the placenta, and are downregulated postnatally. They reexpress in pediatric tumors (e.g. Wilms' tumor) and in inborn developmental syndromes predisposing to such tumors (e.g., Beckwith-Wiedemann syndrome). H19 (RNA transcripts) and IGF2 are manifested in Wilms' tumor, rhabdomyosarcoma, immature ovarian teratoma and gestational trophoblastic diseases. We have found that in the placenta and in urothelial carcinoma, H19 expression reflects the degree of invasiveness. These genes, displaying a tissue-specific oncofetal pattern of expression, are, therefore, tumor markers.

Beckwith-Wiedemann Syndrome↗
PubMed1994

Parallel regulation of parentally imprinted H19 and insulin-like growth factor-II genes in cultured human fetal adrenal cells.

Adjacent, parentally imprinted, insulin-like growth factor-II (IGF-II) and H19 genes are highly expressed during embryogenesis and are important for fetal growth. Human fetal adrenals express abundantly both IGF-II and H19 genes. To clarify the significance and regulation of the H19 gene, we studied its expression in fetal adrenals. In situ hybridization experiments showed H19 RNA expression throughout the fetal adrenal cortex, with slightly higher expression in the outer definitive (adult) than in the inner fetal zone. In primary cultures of fetal adrenal cells, ACTH and other activators of the protein kinase-A signal transduction pathway increased both H19 and IGF-II RNA accumulation 1.7- to 10-fold. Staurosporine, a protein kinase-C inhibitor, increased H19 and IGF-II RNA to the same extent as did ACTH. The protein kinase-C activator 12-O-tetradecanoyl phorbol-13-acetate and cytokines, tumor necrosis factor-alpha and interferon-gamma, inhibited H19 and IGF-II RNA accumulation. Transforming growth factor-beta 1 caused a decrease in levels of H19 and IGF-II RNA, whereas the IGFs caused a slight increase. Our data show parallel multifactorial regulation of H19 and IGF-II RNAs in human fetal adrenal cells. This suggests common regulatory mechanisms for these adjacent genes.

Adrenal Cortex↗
PubMed1994

Ultrastructural characteristics of cytotrophoblast cells during stages of differentiation.

Isolated cytotrophoblast cells from term human placenta were separated into eleven fractions according to cell size, by centrifugal elutriation. Each fraction isolated was examined by electron microscopy to elucidate ultrastructural features consistent with differences in stages of cellular differentiation. As a rule, increasing cell size correlated with evidence of progressive intracellular differentiation. This was represented by the appearance of specialization structures in later fractions, and by changes in the density of organelles and other cellular constituents. Progressive development and maturation of the rough endoplasmic reticulum was also evident. These data are the first to demonstrate successful subfractionation of the heterogeneous cytotrophoblast cell population into distinct groups, each representing different levels of cellular differentiation. These morphologic features of differentiation correlate closely with established biochemical parameters associated with various stages of intermediate cytotrophoblast cell differentiation.

Cell Differentiation↗
PubMed1993

Use of a novel system for defining a gene imprinting region.

Gene imprinting involves the expression of a single allele, depending on its parental origin. In this report, we describe the use of a novel system, implementing human tissues exclusively endowed with either maternally or paternally inherited chromosomes, to better define a known gene imprinting region. Specific RNA transcripts for Placental Ribonuclease Inhibitor (PRI) and Cathepsin D were analysed by northern blotting for expression in complete hydatidiform mole, mature teratoma, and normal placenta. These genes are in close proximity to the reciprocally imprinted H19 and IGF-2 genes found on chromosome 11p15.5. Since all the tissues studied expressed Cathepsin D and PRI, these are not, by definition, imprinted, but as yet we cannot define the borders of the imprinting area on chromosome 11p15.5.

Alleles↗
PubMed1993

The expression of the H-19 and IGF-2 genes during human embryogenesis and placental development.

The H-19 gene in mice is maternally imprinted and its ectopic expression causes prenatal lethality. We have recently identified H-19 transcript in differentiating human placental cells and showed that its expression increases concomitantly with differentiation of cytotrophoblasts in vitro. Placental and embryonal specimens were collected from conception products derived from normal first and second trimester pregnancy terminations. We investigated the abundance of H-19 mRNA throughout placental development in vivo and compared it to the expression of other genes linked to placental differentiation. Furthermore, the expression of H-19 transcript in different organs of human fetuses, aborted during the second trimester, was examined by RNA isolation from separated fetal organs. Since IGF-2 is known to play an important role in embryogenesis, identical blots were hybridized with IGF-2 probe. H-19 expression in human placenta from the different trimesters of pregnancy remains practically constant. A high amount of H-19 gene product was found in the fetoplacental unit with the highest level measured in the adrenal gland. These findings argue that H-19 gene may play a role in human embryogenesis.

Adrenal Glands↗
PubMed1993

A simple and rapid method for staining the enteric ganglia: application for Hirschsprung's disease.

A simple and reliable method is described for staining the nerve plexuses of the human gastrointestinal tract in whole-mounts. The staining does not require fixation and consists of a single step of 6 to 10 minutes incubation in a solution of the fluorescent dye 4-(4-diethylaminostyryl)-methylpyridinium iodide. Aganglionic bowel specimens from 6 patients with Hirschsprung's disease were stained by this method and displayed the absence of ganglion cells and an abundance of nerve fibers in the myenteric and submucosal plexuses. This staining may be suitable for the diagnosis of Hirschsprung's disease.

Child, Preschool↗
PubMed1993

Intermediate cells during cytotrophoblast differentiation in vitro.

Differentiation of the human placental trophoblast cell involves a multistep process, with the generation of several distinct types of intermediate cytotrophoblast cells. Using a short term in vitro cell culture system and centrifugal elutriation, we studied the isolation and morphological and biochemical differentiation of these separated intermediate cell populations. Freshly isolated cell fractions, incubated for 24 h, are heterogeneous in their differentiation stages as determined by the secretion of the proteins chorionic gonadotropin alpha and beta, human placental lactogen, and pregnancy specific beta 1-glycoprotein. Maintenance in cell culture allows for the further differentiation of these intermediate cells and for syncytium formation. With the use of sequential trypsinizations, our data also suggest the parallel differentiation of cytotrophoblast cells into two distinct subsets: one which, through differentiation, gets committed to syncytium formation, and the other, which remains mononuclear despite high degrees of biochemical differentiation. These latter cells retain the capacity for syncytium formation when reintroduced into appropriate culture conditions. These findings refine the use of the term "intermediate cell" by previous investigators. We suggest that our in vitro system defines normal intermediate stages of trophoblast differentiation, and also serves as a model to simulate adverse conditions of syncytial degeneration or injury.

Cell Differentiation↗
PubMed1992

Parental imprinting of the human H19 gene.

It has only recently become clear that genetic imprinting plays an important role in human embryogenesis and in processes leading to the development of pediatric cancers and other human diseases. Using a unique human tissue, the androgenetic complete hydatidiform mole, we established that the maternally inherited allele of the imprinted H19 gene is expressed. Our results also show that the paternal allele of the human IGF-II gene, a gene suspected to be parentally imprinted in humans, is expressed.

Blotting, Northern↗
PubMed1992

Role of infection in the middle lobe syndrome in asthma.

Twenty one children with asthma aged 1.0-10.5 years (mean (SD) 3.3 (2.5) years) were admitted to the hospital to evaluate pulmonary right middle lobe or lingular collapse lasting one to 12 months (mean (SD) 4.4 (3.8) months). Seven children had mild asthma and were treated with inhaled beta 2 agonists as needed. Nine had moderate asthma treated with either sodium cromoglycate or slow release theophylline. Five had severe asthma treated with inhaled steroids. Each child underwent fibreoptic bronchoscopy under local anaesthesia and a bronchoalveolar lavage. Differential cell counts of the lavage fluid revealed predominance of neutrophils in 12 patients (57%). In nine of these patients cultures grew pathogenic bacteria, mainly Haemophilus influenzae and Streptococcus pneumoniae. There was no correlation between the severity of asthma and a positive bacterial culture. There was also no correlation between the duration of the right middle lobe collapse and a positive culture. We conclude that longstanding right middle lobe collapse in asthmatic children is often associated with bacterial infection.

Asthma↗
PubMed1991

Recurrent tetraamelia and pulmonary hypoplasia with multiple malformations in sibs.

A term amelic female infant was born to an apparently nonconsanguineous Arab Moslem couple. This was followed by the birth of 4 normal children. Afterwards, in 2 subsequent pregnancies, 2 amelic fetuses were diagnosed by transabdominal ultrasonography in the 18th and 12th week of gestation. Pregnancies were terminated and on autopsy both amelic fetuses had severe lung hypoplasia and aplasia of the peripheral pulmonary vessels. The first fetus also had apparently low-set ears and micrognathia, whereas the last had hydrocephaly and left cleft lip beside the lung hypoplasia and aberrant pulmonary artery. This appears to be a new autosomal recessive malformation syndrome.

Abnormalities, Multiple↗
PubMed1991

Salicylate as an in vivo free radical trap: studies on ischemic insult to the rat intestine.

Ischemia of rat intestine was induced in vivo by occlusion of the superior mesenteric artery (SMA) for 15 min. Sodium salicylate, 100 mg/kg, given IP, 30 min prior to the ischemic event served as a specific trap for hydroxyl radicals. Portions of the bowel were sequentially isolated and removed--2 min prior to ischemia, 2 min prior to declamping of the SMA, and 10 min following reperfusion. The bowel segments were homogenized in 3% TCA. The homogenate was centrifuged and filtrated through a 0.22 mu filter. The hydroxylation products of salicylate, dihydroxybenzoic acid (DHBA) derivatives, were isolated, identified, and quantified by HPLC coupled with electrochemical detection (ECD). The level of 2,5-DHBA (M +/- SE, ng/g tissue) in the preischemic bowel (N = 21) was 241.8 +/- 10.0. In the ischemic specimen the level of 2,5-DHBA increased significantly to 313.3 +/- 15.5 (p = 0.0129), and remained unchanged in the reperfusion period (322.8 +/- 15.5). The histological examination correlated well with these levels: mild villi damage in the ischemic period with no further exacerbation during the reperfusion period. This study in an in vivo animal model of intestinal ischemia-reperfusion provides direct evidence for the involvement of free radicals during the ischemic insult.

Animals↗
PubMed1991

Endobronchial actinomycosis simulating bronchogenic carcinoma. Diagnosis by bronchial biopsy.

Five cases of actinomycosis of the main bronchi or trachea which were suggestive clinically of bronchogenic carcinoma are described. In four patients the correct diagnosis was made by a bronchial biopsy or wash, or both. Three of them recovered following antibiotic treatment, and one died a few days after bronchoscopy. In one case the Actinomyces were found in the bronchial wash retrospectively following diagnosis of pulmonary actinomycosis in the lobectomy specimen. A concomitant endobronchial lipoma was found in one of the patients. The diagnosis of pulmonary actinomycosis by bronchial biopsy may save the patient major surgical intervention.

Actinomycosis↗