Differential expression of peroxisome proliferator-activated receptors (PPARs) in the developing human fetal digestive tract.

We investigated the spatiotemporal distributions of the different peroxisome proliferator-activated receptor (PPAR) isotypes (alpha, beta, and gamma) during development (Week 7 to Week 22 of gestation) of the human fetal digestive tract by immunohistochemistry using specific polyclonal antibodies. The PPAR subtypes, including PPARgamma, are expressed as early as 7 weeks of development in cell types of endodermal and mesodermal origin. The presence of PPARgamma was also found by Western blotting and nuclease-S1 protection assay, confirming that this subtype is not adipocyte-specific. PPARalpha, PPARbeta, and PPARgamma exhibit different patterns of expression during morphogenesis of the digestive tract. Whatever the stage and the gut region (except the stomach) examined, PPARgamma is expressed at a high level, suggesting some fundamental role for this receptor in development and/or physiology of the human digestive tract.

[Transitory closed-angle glaucoma following a central retinal vein thrombosis]. / Glaucome par fermeture transitoire de l'angle consécutif à une thrombose de la veine centrale de la rétine.

This article reports a case in which an occlusion of the central retinal vein of one eye was accompanied by transitory shallowness of the anterior chamber, partial closure of the angle and elevation of the intraocular pressure.

[Sarcoidosis and rubeosis iridis]. / Sarcoïdose et rubeosis iridis.

In this case of sarcoidosis the prominent ophthalmologic manifestation was neovascularization of the iris and of the angle, with glaucoma.

Choroidal and retinal detachment following argon laser iridotomy.

This case report examines another of the many complications resulting from argon laser iridotomy. The authors believe that choroidal and retinal detachment subsequent to argon laser iridotomy are a product of the exceptionally high cumulative energy used in the procedure and might result from changes induced in the chamber angle. Although the authors could not prospectively find any choroidal or retinal detachment in the patient, they think that it might occur subclinically and must be suspected in a pale iris if the energy used is high and/or if vision is transiently lowered during the postoperative period.

[Maculopathy with golden particles]. / Maculopathie en paillettes d'or.

This article describes two patients with a bilateral maculopathy due to the presence of numerous glistening yellow particles located mainly around the edge of the macular pit. This picture has apparently not been reported before. Further studies are needed to confirm a possibly toxic origin.

[Canthaxanthine retinopathy: 1. Clinical study in 51 consumers]. / La rétinopathie à la canthaxanthine: 1. Etude clinique de 51 consommateurs.

Canthaxanthine, a non-provitamin A carotenoid, has been marketed in Canada since March 1979 as a skin-tanning agent. Fifty-one individuals who ingested from 3.6 to 66 g of the drug within a 24-month period were ophthalmologically evaluated. Six of them had deposits in the ocular fundus that appeared to be related to ingestion of the substance, but no functional impairment could be detected.

Testicular interstitial cell tumor and gynecomastia in a rabbit.

Unilateral testicular interstitial (Leydig) cell tumor and gynecomastia were diagnosed in an adult male rabbit. The interstitial cell tumor was a well-circumscribed, 2-mm diameter, pale tan nodule composed of a uniform population of polygonal cells. Neoplastic interstitial cells exhibited diffuse, granular cytoplasmic staining with Melan A, a marker of steroid-producing cells in humans and dogs. Multiple subcutaneous masses in the caudal abdomen were associated with enlarged nipples and consisted of hyperplastic mammary gland tissue with proliferation of ducts and alveoli, marked lobule formation, and pseudolactational hyperplasia. Many epithelial cells lining the hyperplastic ducts and alveoli exhibited intense nuclear expression of progesterone receptor antigen, whereas myoepithelial cells showed strong nuclear staining for p63 antigen. This is the first report of concurrent interstitial cell tumor and gynecomastia in a rabbit and also the first description of gynecomastia in this species.

Differential effects of epidermal growth factor and hydrocortisone in human fetal colon.

The influence of epidermal growth factor (EGF) and hydrocortisone on the functional development of human fetal colon was studied in organ cultures. Fetal colon (14 to 17 weeks gestation) was cultured for 5 days at 37 degrees C in serum-free Leibovitz L-15 medium alone or supplemented with 1, 10, and 100 ng of EGF/ml or with 50 ng of hydrocortisone/ml of culture medium. The overall morphology of the colonic explants was not altered by the hormonal addition. In the continuous presence of EGF (1, 10, and 100 ng/ml) for 5 days, a significant decrease of [3H]thymidine incorporation into DNA was observed. At the brush border level, the addition of EGF induced a significant drop in sucrase, maltase, and alkaline phosphatase activities. These enzymic modifications occurred between the third and fifth day of culture, whereas variation in DNA synthesis was already evident within 24 h. The addition of hydrocortisone at a dose affecting the small intestine (50 ng/ml) did not significantly influence colonic DNA synthesis nor the digestive enzymic activities. These observations show for the first time that EGF, but not hydrocortisone, influences the proliferation and differentiation of human fetal colonic mucosa.

Insulin modulates cellular proliferation in developing human jejunum and colon.

Several lines of evidence suggest an important role for insulin in the regulatory mechanism of rodent small intestinal development. To investigate its potential implication in human gut, the immunofluorescent localization of insulin receptors (IR) and the influence of insulin (30 microU or 3 mU/ml) on [3H]-thymidine incorporation and on lactase and alkaline phosphatase activities were studied in fetal jejunum and colon (14-19 weeks). We demonstrate the early presence of IR, mainly detected in the basolateral portion of enterocytes and colonocytes along the crypt-villus axis. Insulin increased [3H]-thymidine incorporation as well as epithelial labeling indices in cultured explants from jejunum and colon without affecting enzymic activities. This study establishes, for the first time, that insulin stimulates proliferation of epithelial cells expressing IR in both segments without affecting brush border hydrolases in the developing human gut.

Functional characterization of the keratinocyte growth factor system in human fetal gastrointestinal tract.

Keratinocyte growth factor (KGF) is a paracrine growth factor whose mRNA has been detected in human adult and rodent gut tissues together with its associated receptor. Our objectives were to assess the presence of immunoreactive KGF ligand and receptor proteins in human fetal gastrointestinal (GI) tract segments and to evaluate the role of exogenous KGF on cell proliferation and intestinal digestive functions. KGF (26-28 kD doublet) was identified in esophagus, stomach, small intestine, and colon by Western blot. Its receptor (135 kD) was ubiquitously detected in proliferative and differentiated epithelial cells of each GI segment by use of indirect immunofluorescence (anti-bek, anti-K-sam). The addition of KGF to explants cultured in serum-free conditions greatly stimulated DNA synthesis in all GI tract tissues. The growth factor up-regulated intestinal sucrase-isomaltase and gamma-glutamyl-transpeptidase activities in jejunal explants, whereas it down-regulated these activities in colon explants. It is suggested that the KGF system likely represents an important paracrine pathway that is able to stimulate cell proliferation in all segments of the human fetal GI tract and to differentially regulate intestinal digestive functions.