Biomedical subjects

M Heikinheimo

Publications and source records attributed to M Heikinheimo.

At least 19 recordsLinked to original sources

PubMed1996

Erythropoiesis and vasculogenesis in embryoid bodies lacking visceral yolk sac endoderm.

During mouse embryogenesis the first hematopoietic and endothelial cells form in blood islands located between layers of visceral endoderm and mesoderm in the yolk sac. The role of visceral endoderm in primitive hematopoiesis and vasculogenesis is not well understood. We have assessed the consequences of a lack of visceral endoderm on blood cell and vessel formation using embryoid bodies derived from mouse embryonic stem (ES) cells deficient in GATA-4, a transcription factor expressed in yolk sac endoderm. When differentiated in vitro, these mutant embryoid bodies do not develop an external visceral endoderm layer. We found that Gata4-/- embryoid bodies, grown either in suspension culture or attached to a substratum, are defective in primitive hematopoiesis and vasculogenesis as evidenced by a lack of recognizable blood islands and vascular channels and a reduction in the expression of the primitive erythrocyte marker epsilon y-globin. Expression of the endothelial cell transcripts FIk-1, FIt-1, and platelet-endothelial cell adhesion molecule (PECAM) was not affected in the mutant embryoid bodies. Gata4-/- ES cells retained the capacity to differentiate into primitive erythroblasts and endothelial cells when cultured in methylcellulose or matrigel. Analysis of chimeric mice, generated by injecting Gata4-/- ES cells into 8-cell stage embryos of ROSA26 transgenic animals, showed that Gata4-/- ES cells can form blood islands and vessels when juxtaposed to visceral endoderm in vivo. We conclude that the visceral endoderm is not essential for the differentiation of primitive erythrocytes or endothelial cells, but this cell layer plays an important role in the formation and organization of yolk sac blood islands and vessels.

Animals↗

PubMed1996

The gene for transcription factor GATA-6 resides on mouse chromosome 18 and is expressed in myocardium and vascular smooth muscle.

We report the mapping and developmental expression pattern of the gene encoding mouse GATA-6, a member of a family of transcription factors involved in tissue-specific gene expression. Using backcross analysis, the Gata6 gene was localized to mouse chromosome 18, linked to the gene encoding transthyretin. RNase protection analysis showed that Gata6 is abundantly expressed in the heart, stomach, intestine, and ovaries of the adult mouse. The developmental expression patterns of Gata6 and the closely related gene Gata4 were directly compared using in situ hybridization. Both genes were found to be highly expressed in the myocardium, stomach epithelium, and small intestinal epithelium throughout mouse development. Of the two genes, however, only Gata6 was expressed in vascular smooth muscle. The overlapping distributions of GATA-4 and GATA-6 transcripts in the heart support the possibility of functional redundancy or interplay between these two transcription factors in this tissue. The presence of GATA-6 mRNA in vascular smooth muscle suggests that this transcription factor may play a distinctive role in gene expression in this cell type.

Animals↗

PubMed1995

The GATA-4 transcription factor transactivates the cardiac-specific troponin C promoter-enhancer in non-muscle cells.

The unique contractile phenotype of cardiac myocytes is determined by the expression of a set of cardiac-specific genes. By analogy to other mammalian developmental systems, it is likely that the coordinate expression of cardiac genes is controlled by lineage-specific transcription factors that interact with promoter and enhancer elements in the transcriptional regulatory regions of these genes. Here, we demonstrate that the slow/cardiac-specific troponin C (cTnC) enhancer contains a specific binding site for the lineage-restricted, zinc finger transcription factor, GATA-4 and that GATA-4 mRNA and protein is expressed in cardiac myocytes. In addition, GATA-4 binding sites were identified in several previously characterized cardiac-specific transcriptional regulatory elements. The cTnC GATA-4 binding site is required for transcriptional enhancer activity in primary cardiac myocytes. Moreover, the cTnC enhancer can be transactivated by over-expression of GATA-4 in non-cardiac muscle cells such as NIH 3T3 cells. Taken together, these results are consistent with a model in which GATA-4 functions to direct tissue-specific gene expression during mammalian cardiac development.

3T3 Cells↗

PubMed1995

Tumor markers CA 125 and CA 19-9 in cord blood and during infancy: developmental changes and use in pediatric germ cell tumors.

Tumor markers CA 125 and CA 19-9 are elevated in a variety of malignancies in adult patients, but only little is known of their biology during gestation or infancy. We have addressed the developmental pattern of these carbohydrate antigens in pediatric patients by measuring their serum levels in 133 cord blood samples from the second through third trimester of gestation and in 39 infants aged less than 1.5 y. The serum concentrations of both markers revealed developmental changes, the levels being higher at earlier gestation (wk 24 through 37) than at term or during infancy. The clinical value of the markers was evaluated by monitoring 26 children with germ cell tumors; 14 benign and 2 immature teratomas, and 11 malignant germ cell tumors. Patients with immature sacrococcygeal teratomas showed constant and prolonged elevations of serum CA 125 and CA 19-9. In contrast, all but two children with mature teratomas had normal marker levels; these two patients with abnormally high serum CA 125 and CA 19-9 values for the first 4 postoperative weeks had a benign ovarian and ventricular teratoma, respectively. Of the 11 children with malignant germ cell tumors, serum CA 125 or CA 19-9 concentration was elevated in four patients at diagnosis and declined to normal within 2 wk after institution of therapy. Malignant recurrence in two patients was not associated with a reelevation of the CA 125 level. Taken together, our results demonstrate a developmentally regulated pattern of serum CA 125 and CA 19-9. The carbohydrate markers were usually inferior to alpha-fetoprotein in monitoring of germ cell tumors, but may be a useful adjunct in the follow-up of immature teratomas.

CA-125 Antigen↗

PubMed1995

FGF-8 isoforms activate receptor splice forms that are expressed in mesenchymal regions of mouse development.

The Fgf8 gene is expressed in developing limb and craniofacial structures, regions known to be important for growth and patterning of the mouse embryo. Although Fgf8 is alternatively spliced to generate at least 7 secreted isoforms that differ only at their mature amino terminus, the biological significance of these multiple isoforms is not known. In this report, we demonstrate that multiple FGF-8 isoforms are present at sites of Fgf8 expression during mouse development. To address the possibility that the FGF-8 isoforms might interact with different fibroblast growth factor receptors, we prepared recombinant FGF-8 protein isoforms. We examined the ability of these proteins to activate alternatively spliced forms of fibroblast growth factor receptors 1-3, and fibroblast growth factor receptor 4. Recombinant FGF-8b and FGF-8c activate the 'c' splice form of FGFR3, and FGFR4, while FGF-8b also efficiently activates 'c' splice form of FGFR2. No activity could be detected for recombinant or cell expressed FGF-8a. Furthermore, none of the isoforms tested interact efficiently with 'b' splice forms of FGFR1-3, or the 'c' splice form of FGFR1. These results indicate that the FGF-8b and FGF-8c isoforms, produced by ectodermally derived epithelial cells, interact with mesenchymally expressed fibroblast growth factor receptors. FGF-8b and FGF-8c may therefore provide a mitogenic signal to the underlying mesenchyme during limb and craniofacial development.

Alternative Splicing↗

PubMed1995

Targeted mutagenesis of the transcription factor GATA-4 gene in mouse embryonic stem cells disrupts visceral endoderm differentiation in vitro.

Transcription factor GATA-4 belongs to a family of zinc finger proteins involved in lineage determination. GATA-4 is first expressed in yolk sac endoderm of the developing mouse and later in cardiac tissue, gut epithelium and gonads. To delineate the role of this transcription factor in differentiation and early development, we studied embryoid bodies derived from mouse embryonic stem (ES) cells in which both copies of the Gata-4 gene were disrupted. Light and electron microscopy demonstrated that embryoid bodies formed from wild-type and heterozygous deficient ES cells were covered with a layer of visceral yolk sac endoderm, whereas no yolk sac endoderm was evident on the surface of the homozygous deficient embryoid bodies. Independently selected homozygous deficient cell lines displayed this distinctive phenotype, suggesting that it was not an artifact of clonal variation. Biochemical markers of visceral endoderm formation, such as alpha-feto-protein, hepatocyte nuclear factor-4 and binding sites for Dolichos biflorus agglutinin, were absent from the homozygous deficient embryoid bodies. Examination of other differentiation markers in the mutant embryoid bodies, studies of ES cell-derived teratocarcinomas and chimeric mouse analysis demonstrated that GATA-4-deficient ES cells have the capacity to differentiate along other lineages. We conclude that, under in vitro conditions, disruption of the Gata-4 gene results in a specific block in visceral endoderm formation. These homozygous deficient cells should yield insights into the regulation of yolk sac endoderm development and the factors expressed by visceral endoderm that influence differentiation of adjoining ectoderm/mesoderm.

Animals↗

PubMed1995

FGF-8 isoforms differ in NIH3T3 cell transforming potential.

We previously identified Fgf-8 as a frequently activated gene in tumors from mouse mammary tumor virus-infected Wnt-1 transgenic mice, suggesting that Fgf-8 is a proto-oncogene. We further determined that multiple, secreted protein isoforms that differ at their mature amino termini are encoded by alternatively spliced mRNAs transcribed from the gene. We now present evidence that there are differences in the potency of NIH3T3 cell transformation displayed by three of the FGF (fibroblast growth factor)-8 isoforms. We find that stable transfection of a cDNA for the FGF-8b isoform leads to marked morphological transformation of NIH3T3 cells and rapid tumorigenicity of the transfected cells in nude mice. In contrast, transfection of a cDNA for the FGF-8a or FGF-8c isoform results in moderate morphological changes in the NIH3T3 cells, and the transfected cells are weakly tumorigenic in nude mice. All three transfections result in cells that express comparable amounts of Fgf-8 mRNA and that produce the FGF-8 protein isoforms. The morphological changes observed in NIH3T3 cells can be reproduced by the addition of recombinant FGF-8 protein isoforms to the culture medium. Therefore, these results indicate that there are differences in the potency of transformation of NIH3T3 cells by FGF-8 protein isoforms and suggest that these FGF-8 isoforms may have different in vivo functions.

3T3 Cells↗

PubMed1994

Serum procollagen type III is an early and sensitive marker for veno-occlusive disease of the liver in children undergoing bone marrow transplantation.

Veno-occlusive disease of the liver (VOD) is a life-threatening complication occurring in patients undergoing bone marrow transplantation (BMT). Although clinical signs and laboratory parameters such as elevation of serum bilirubin often suggest this condition, it would be useful to identify early biochemical markers for VOD. Fibrous alterations in the hepatic venules and small lobular veins occur during development of VOD; these changes are accompanied by the deposition of types I and III collagen in the liver tissue. Since the N-terminal propeptide of type III procollagen (PIIINP) is a sensitive marker of liver and lung fibrosis, we undertook a study to evaluate the usefulness of measurements of serum PIIINP in children with VOD. Seven of the 28 children who underwent BMT, both allogenic and autologous, developed VOD. All seven had an increase of more than 100 ng/mL in the serum PIIINP level, whereas only one of the remaining 21 children not affected by VOD had an increment of PIIINP more than 100 ng/mL (P = .0001). The levels of serum PIIINP were higher in the VOD group during the follow-up period of up to 91 days after BMT. The elevation of PIIINP also occurred at a stage of the disease usually preceding any other laboratory or clinical signs of VOD. Serum concentration of PIIINP thus seems to be of value as an early marker for VOD in children undergoing BMT.

Adolescent↗

PubMed1994

Immuno- and cytochemical characterization of congenital leukemia: a case report.

Congenital leukemia (CL) is a rare disorder, which usually presents as a myelocytic leukemia based on morphological features. Very few reports include data on cyto- or immunochemical parameters. A case of CL with detailed description of immunochemical, cytochemical features, and colony formation properties of the progenitor cells is reported. This leukemia was classified as an M4 in FAB classification based on the morphological features and special stains. Two different cell populations were identified by flow cytometry. One consisted of small cells expressing early T- and early B-cell associating antigens as well as early myeloid-associated antigens, but not CD10 (CALLA antigen), which is normally present in cord blood lymphocytes. The other was a population of large cells expressing myeloid-associated antigens and a pan-T-antigen. The growth pattern of hematopoietic progenitors in the patient was compatible with both acute myeloid and acute lymphatic leukemia as well as erythroleukemia.

Bone Marrow↗

PubMed1994

Localization of transcription factor GATA-4 to regions of the mouse embryo involved in cardiac development.

To clarify the role of transcription factor GATA-4 in mammalian development, we have determined the pattern of expression of GATA-4 in early postimplantation mouse embryos. Using in situ hybridization and immunohistochemistry, we find that GATA-4 RNA and protein are expressed in cells associated with heart development. Intraembryonic expression of GATA-4 RNA is first apparent in coelomic epithelial cells of the primitive streak embryo (approximately 7.0-7.5 days postcoitum). During formation and bending of the heart tube (approximately 8 days postcoitum), GATA-4 RNA and protein are expressed in endocardium, myocardium, and embryonic structures containing precardiac mesoderm such as the septum transversum and intraembryonic coelomic epithelium. By the onset of cardiac septation (approximately 9 days postcoitum), abundant GATA-4 RNA expression is evident in endocardium, endocardial cushion tissue, and myocardium. Expression of GATA-4 by the myocardium continues through gestation and after birth. The temporal and spacial patterns of GATA-4 expression support a role for this factor in the regulation of cardiac differentiation, analogous to the established role of transcription factor GATA-1 in the regulation of hematopoiesis.

Animals↗

PubMed1994

Fgf-8 expression in the post-gastrulation mouse suggests roles in the development of the face, limbs and central nervous system.

Fgf-8 is a member of the fibroblast growth factor (FGF) family that was initially identified as an androgen-inducible growth factor in a mammary carcinoma cell line. Alternative splicing of the primary Fgf-8 transcript results in three messenger RNAs which code for secreted FGF-8 protein isoforms that differ only in their mature amino termini. Fgf-8 RNA is present from day 10 through 12 of murine gestation when analyzed by northern blot analysis, suggesting that Fgf-8 normally functions during post-gastrulation development. To characterize the temporal, spatial and isoform-specific aspects of Fgf-8 expression during mouse development, we performed in situ hybridization and ribonuclease protection assays between the days 8 and 16 of gestation. Fgf-8 expression is first detected at day 9 of gestation in the surface ectoderm of the first branchial arches, the frontonasal process, the forebrain and the midbrain-hindbrain junction. At days 10-12 of gestation, Fgf-8 expression is detected in the surface ectoderm of the forelimb and hindlimb buds, in the nasal pits and nasopharynx, in the infundibulum and in the telencephalon, diencephalon and metencephalon. Fgf-8 expression continues in the developing hindlimbs through day 13 of gestation but is undetectable thereafter. Ribonuclease protection assays reveal that RNAs coding for all three FGF-8 isoforms are present at days 10-12 of gestation. These results reveal a unique temporal and spatial pattern of Fgf-8 expression in the developing mouse and suggest a role for this FGF in multiple regions of ectodermal differentiation in the post-gastrulation mouse embryo.

Animals↗

PubMed1994

The GATA-4 transcription factor transactivates the cardiac muscle-specific troponin C promoter-enhancer in nonmuscle cells.

The unique contractile phenotype of cardiac myocytes is determined by the expression of a set of cardiac muscle-specific genes. By analogy to other mammalian developmental systems, it is likely that the coordinate expression of cardiac genes is controlled by lineage-specific transcription factors that interact with promoter and enhancer elements in the transcriptional regulatory regions of these genes. Although previous reports have identified several cardiac muscle-specific transcriptional elements, relatively little is known about the lineage-specific transcription factors that regulate these elements. In this report, we demonstrate that the slow/cardiac muscle-specific troponin C (cTnC) enhancer contains a specific binding site for the lineage-restricted zinc finger transcription factor GATA-4. This GATA-4-binding site is required for enhancer activity in primary cardiac myocytes. Moreover, the cTnC enhancer can be transactivated by overexpression of GATA-4 in non-cardiac muscle cells such as NIH 3T3 cells. In situ hybridization studies demonstrate that GATA-4 and cTnC have overlapping patterns of expression in the hearts of postimplantation mouse embryos and that GATA-4 gene expression precedes cTnC expression. Indirect immunofluorescence reveals GATA-4 expression in cultured cardiac myocytes from neonatal rats. Taken together, these results are consistent with a model in which GATA-4 functions to direct tissue-specific gene expression during mammalian cardiac development.

3T3 Cells↗

PubMed1994

Serum levels of oncofetal markers CA 125, CA 19-9, and alpha-fetoprotein in children with hereditary tyrosinemia type I.

Hereditary tyrosinemia type I (HTT-I) is an inherited metabolic disorder with severe liver disease and a high risk for hepatic malignancy. Patients with HTT-I are monitored with repeated analyses of serum amino acids, urine succinylacetone, and serum alpha-fetoprotein (AFP). Oncofetal markers CA 125 and CA 19-9 are elevated in serum of patients with various gastrointestinal diseases and malignancy. To study the biology of oncofetal antigens in tyrosinemia and to assess the possible usefulness of these markers in HTT-I, we studied serum concentrations of CA 125 (n = 160) and CA 19-9 (n = 188), together with AFP (n = 337), in serial samples from 10 patients. At early stages of the disease, most children with an acute type of disease had a remarkably elevated serum CA 125 concentration (153-1560 IU/L) that normalized gradually after the institution of therapy. Serum CA 125 levels may thus reflect acute metabolic imbalance in fulminant HTT-I. The patients with a chronic type of disease showed CA 125 levels within the normal range at diagnosis that slowly increased as the liver condition worsened. These concentrations, however, never reached values seen in acute HTT-I. Serum concentration CA 19-9 in HTT-I was mostly normal. Serum AFP levels fluctuated in all patients and positively correlated with tests for metabolic state and biliary function. A distinct increase in the serum AFP level was recorded in association with the detection of massive hepatocellular carcinoma and also preceded metabolic imbalance leading to porphyria crises.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Metabolism, Inborn Errors↗

PubMed1994

Early rise in serum concentration of transferrin receptor induced by recombinant human erythropoietin in very-low-birth-weight infants.

The serum transferrin receptor (TfR) level reflects iron status and the rate of erythropoiesis. This study was undertaken to assess the role of serum TfR in the iron status and erythropoiesis in very-low-birth-weight infants under conditions in which erythropoiesis is stimulated by large doses of recombinant human erythropoietin (rHuEPO) and oral iron. The first 34 infants were followed from the 3rd to 11th wk of life or until discharged. They received iron at a rate of 3 mg/kg/d. The subsequent 21 infants were given rHuEPO (300 U/kg three times a week s.c.) and iron at a rate of 6 mg/kg/d from the 3rd or 4th wk of life for a mean of 3.4 wk. With this treatment, the need for transfusion was reduced from 1.4 +/- 0.4 to 0.1 +/- 0.1 transfusions per infant (p = 0.02). The serum TfR concentrations in the rHuEPO-treated infants increased gradually to values several-fold higher than those in the untreated infants. This increase was not related to intrauterine or postnatal growth, protein intake, or serum albumin concentration. Neither was an association observed between Hb and TfR concentration. In the treated infants, the serum ferritin concentration was lower at the 4th, 5th, and 7th wk of life than in the untreated infants. The very-low-birth-weight infants who were given large doses of rHuEPO and iron had a marked rise in serum TfR concentration and a small decline in serum ferritin concentration. These events have been related to iron deficiency.

Administration, Oral↗

PubMed1994

Successful treatment of ARDS with two doses of synthetic surfactant.

A 50-year-old man with adult respiratory distress syndrome (ARDS) was successfully treated with synthetic surfactant. The therapy rapidly improved the respiratory function; it also increased the release of endogenous surfactant. Synthetic surfactant may thus be of value in the treatment of ARDS.

Drug Combinations↗

PubMed1993

Neonatal benign sacrococcygeal teratoma may recur in adulthood and give rise to malignancy.

BACKGROUND: The capacity of neonatal sacrococcygeal teratomas (SCT) to recur is a well-recognized phenomenon. However, only a few studies have reported recurrence of the tumors beyond childhood. METHODS: A follow-up of patients for the detection of late recurrent SCT was performed in 45 patients, ages 4-43 years (mean, 21.5 years). All of the patients had been operated on in infancy for a benign SCT. RESULTS: Three adults with persistent or recurrent SCT were found. The recurrent tumors were diagnosed 21-43 years after the initial diagnosis and operative treatment. Two recurrences were histologically benign, and one was malignant. In the patient with the malignant recurrence, the coccyx was not removed primarily. The malignant recurrence was a mucinous adenocarcinoma and probably originated from a preexisting benign epithelial component of the teratoma. CONCLUSIONS: The capacity of a benign SCT to recur may be retained into adulthood. Follow-up of patients after operation for a SCT, even when the tumor is benign, should extend far beyond infancy. Abdominal radiographs may help detect late recurrent tumors with intrapelvic calcifications. When any recurrence is found, malignancy should be suspected.

Adenocarcinoma, Mucinous↗

PubMed1993

Anorectal function in adults operated for a benign sacrococcygeal teratoma.

Fecal continence and quality of life were evaluated by a questionnaire in 26 adult patients (mean age, 30 years; 6 men, 20 women) who had undergone surgery for a benign sacrococcygeal teratoma in infancy. The fecal continence was assessed by a score described by Holschneider. Twenty-six healthy people with a similar age and sex distribution were used as controls. Good fecal continence was reported by 88% of the patients; however, only 27% had completely normal bowel habits. Some fecal soiling was present in 27% of the patients. No correlation between the severity of aberrations in anorectal functions and the degree of intrapelvic extension of the tumor was found. Social problems related to deficient anorectal function were reported by 27% of the patients. Other health problems including urinary incontinence were reported by 50% of the patients. All the controls had good fecal continence; 77% of them had completely normal bowel habits. The present study shows that at the adult age, a significant proportion of patients who have undergone surgery for sacrococcygeal teratoma suffer from deficient anorectal function and a diminished quality of life.

Adult↗

PubMed1992

N-terminal propeptide of type III collagen in tracheal fluid and serum in preterm infants at risk for bronchopulmonary dysplasia.

Bronchopulmonary dysplasia (BPD) is a common pulmonary complication in preterm infants that leads to fibrosis of the bronchoalveolar walls and often to severe clinical consequences. Type III collagen is deposited early in progressive fibrosis. Because the N-terminal propeptide of type III collagen (PIIINP), a by-product of type III collagen synthesis, reflects the degree of pulmonary fibrosis in adults, we hypothesized that PIIINP in tracheal aspirates and/or serum may be a useful early marker of developing BPD in neonates. We serially measured PIIINP in tracheal fluid and serum samples during the first weeks of life in 41 consecutive respirator-treated preterm infants (mean birth weight 1067 g, mean gestational age 28.3 wk). Eight of the infants died and 22 infants fulfilled the criteria for BPD at age 28 d. The mean level of PIIINP decreased with advancing postnatal age in tracheal fluid but not in serum. The mean tracheal fluid PIIINP during d 1 and 2 of life, respectively, was 175 and 200 ng/mg protein in infants who were still in a respirator at age 28 d (n = 13), 122 and 97 ng/mg protein in those who were weaned earlier (n = 20), and 50 and 30 ng/mg protein in those who died before age 28 d (n = 8). These differences are not statistically significant, and the variability of the values was large. The PIIINP concentrations in tracheal aspirates of infants subsequently developing BPD did not differ from those without BPD. Neither did the levels correlate with the degree of BPD or radiologically defined fibrosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Biomarkers↗