Biomedical subjects

W M Calonge

Publications and source records attributed to W M Calonge.

4 recordsLinked to original sources

PubMed2007

Expression of homeotic genes Hoxa3, Hoxb3, Hoxd3 and Hoxc4 is decreased in the lungs but not in the hearts of adriamycin-exposed mice.

Exposure of rat and mouse embryos to adriamycin (doxorubicin chlorhydrate) induces esophageal atresia (EA) and VACTERL association. Sonic hedgehog (Shh) and Gli2/Gli3 pathways are involved in these conditions and knockout mice for homeotic Hox genes Hoxa3, Hoxb3, Hoxc3, Hoxc4 and Hoxa5 show phenotypes with some of the associated VACTERL features. This study aims at evaluating the possible influence of Hoxa3, Hoxb3, Hoxd3 and Hoxc4 as upstream regulators of this complex signalling. Pregnant mice were exposed either to 4 mg/kg of adriamycin (EA group) or vehicle (controls) on embryonic days 7.5 and 8.5. Embryos were recovered at four endpoints (E12.5-E15.5) and randomly assigned for immunohistochemical or molecular biology studies. Lungs and hearts were separately harvested and processed for Hoxa3, Hoxb3, Hoxd3 and Hoxc4 quantitative RT-PCR measurements. Antibodies for Hoxa3, Hoxb3 and Hoxd3 proteins were used for immunohistochemical studies. RT-PCR studies showed a drastic and statistically significant decrease of the four genes in the lungs of EA mice when compared to controls, with a slight recovery from E15.5. Hearts of both groups showed a similar expression of all the genes throughout gestation. Control embryos expressed the hox3 paralogous genes in heart, skin, foregut derivatives and their surrounding mesoderm through E12.5-E15.5 whereas adriamycin-exposed embryos showed a severe decrease in expression of these three proteins in the same tissues but not in the heart. Adriamycin drastically reduced the expression of Hoxa3, Hoxb3, Hoxd3 and Hoxc4 in mice embryonic lungs. Their expression in the heart did not seem to be influenced by adriamycin in this experimental setting.

Animals↗

PubMed2006

[Thyroid C cells are decreased in experimental CDH].

BACKGROUND/AIM: Experimental CDH is often associated with malformations of neural crest origin. Several of these features are present in human CDH and therefore likely similar pathogenic mechanisms should be explored. The aim of the present study is to examine whether thyroid C-cells, another neural crest derivative, are abnormal in this rat model. METHODS: Pregnant rats were exposed either to 100 mg of 2-4-dichlorophenyl-p-nitrophenyl ether (nitrofén) or vehicle (controls) on 9.5 day of gestation. Fetuses were recovered on day 21st and the thyroids of those with CDH (68%) were immuno-histochemically stained with anti-calcitonin antibody. The number of positively stained cells per high power field were counted using a computer-assisted image analysis method in at least 5 sections per thyroid. The distribution of the cells within the gland was assessed as well. Comparisons between CDH and control rats were made by non-parametric tests with a significance threshold of p<0.05. RESULTS: The number of c-cells was dramatically reduced in CDH animals in comparison with controls (101.2 +/- 61.3 vs 23.1 +/- 37, p<0.0001). Histology of the thyroid was similar in both groups, but the distribution of positive C-cells within the gland followed an abnormal pattern in CDH rats with the cells tending to be located at the periphery rather than at the core of the lobes. CONCLUSIONS: Nitrofén induces a severe decrease in thyroid C cells accompanied by abnormal distribution patterns. These results add further evidence of the involvement of a neural crest dysregulation as a component of the pathogenesis of experimental CDH. Whether there is or not a clinical counterpart to these findings is still unknown, but the nature of the cardiovascular and craneo-facial malformations in some babies with CDH strongly support further research in this field.

Animals↗

PubMed2004

Decrease of parafollicular thyroid C-cells in experimental esophageal atresia: further evidence of a neural crest pathogenic pathway.

Adriamycin-induced experimental esophageal atresia (EA) is often associated with malformations of neural crest (NC) origin, such as abnormal pharyngeal pouch derivatives like the thymus and the parathyroids. The aim of the present study was to examine whether NC-derived thyroid C-cells were abnormal in a rat model. Pregnant rats received intraperitoneally either 2 mg/kg Adriamycin (EA) or vehicle (controls) on days 8 and 9 of gestation. Fetuses were recovered on day 21, and blocks including the trachea and thyroid were fixed in formalin, coronally sectioned at 3-mum widths, and stained with standard hematoxylin and eosin until the largest area of thyroid was reached. From this point on, the 1st, 10th, and 20th slices were immunohistochemically stained with anti-calcitonin antibody. Positively-stained cells in each section of the gland were counted using a computer-assisted image analysis method, and the results were averaged. The distribution of the cells within the gland was assessed as well. Comparisons between EA and control rats were made by nonparametric tests with a significance threshold of p<0.05. The number of C-cells was dramatically reduced in EA animals compared with controls (32.4+/-36 vs. 92.3+/-60.5, p<0.001). Histology of the thyroid was similar in both groups, but the distribution of positive C-cells within the gland followed an abnormal pattern in EA rats. Adriamycin causes a pattern of NC-derived malformations, including a severe decrease in thyroid C-cells accompanied by abnormal distribution or migration patterns. These results represent further evidence of the involvement of NC organogenic control dysregulation in the pathogenesis of EA and its associated malformations. The similarities between the rat model and the clinical picture strongly support investigating other subclinical NC-derived anomalies in patients with EA.

Animals↗

PubMed2003

Congenital left-sided Bochdalek diaphragmatic hernia. Thoracoscopic repair--case report.

The authors report the case of a 12-year-old girl who presented with a left-sided diaphragmatic hernia that was diagnosed after a pulmonary infection. CT scan confirmed a posterolateral diaphragmatic Bochdalek defect. The child underwent a thoracoscopic repair of the defect in 1997. The herniated contents included spleen, stomach, and intestine. The child was discharged from hospital the day after surgery. She has been followed up and is clinical and radiologically well.

Child↗