Publications by authors named "C Van Dop"

The influence of chronically administered host-targeted drugs on the gut microbiome remains less understood compared to antibiotics. We investigated repetitive exposure effects of three common antiseizure medications [carbamazepine (CBZ), valproic acid, and levetiracetam] on the gut microbial composition, resistome, and metabolome using microcosms constructed from feces of young children. Microcosms were established by cultivating feces for 24 h (C0).

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Recently, a unique Pro250Arg point mutation in fibroblast growth factor receptor 3 (FGFR3) was reported in 61 individuals with coronal craniosynostosis from 20 unrelated families [Muenke et al. (1997): Am J Hum Genet 60:555-564]. The discovery of this apparently common mutation has resulted in the definition of a recognizable syndrome, through analysis of subtle clinical findings in families who were previously thought to have a variety of other craniosynostosis syndromes.

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While loss-of-function mutations in Gsalpha are invariably associated with the short stature and brachydactyly of Albright hereditary osteodystrophy (AHO), the association with hormone resistance (to parathyroid hormone and thyrotropin) typical of pseudohypoparathyroidism type Ia (PHP-Ia) is much more variable. Observational studies and DNA polymorphism analysis suggest that maternal transmission of the Gsalpha mutation may be required for full expression of clinical hormone resistance. To test this hypothesis, we studied transmission of a frameshift mutation in Gsalpha through three generations of a pedigree affected by AHO and PHP-Ia.

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The activation of cell-surface receptors usually produces a transient increase of the extracellular acidification rate in culture cells that can be detected with a biosensor-based instrument. We describe here the application of this method in monitoring hormonal response of Galphas-deficient fibroblasts from patients with pseudohypoparathyroidism type Ia (PHP-Ia). We found that following exposure to isoproterenol, the mean acidification response of fibroblasts from four PHP-Ia patients was only 18% of the response in normal cells.

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Defects in the G (guanine nucleotide-binding)-protein subunit (G alpha s) which stimulates adenylyl cyclase may result in either loss or gain of endocrine function. Reduced G alpha s activity is found in the hormone resistance syndrome, pseudohypoparathyroidism type Ia (PHP-Ia), while constitutive activation of G alpha s is associated with endocrine organ overactivity, including the gonadotropin-independent sexual precocity seen in patients with McCune-Albright syndrome. We identified two unrelated boys presenting with concurrent PHP-Ia and gonadotropin-independent sexual precocity (testotoxicosis).

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