Development of the lung in mice with bromodeoxyuridine-induced cleft palate

Associated anomalies among infants with oral clefts at birth and during a 1-year follow-up

Reports of birth defects rates may focus on defects observed in the newborn period or include defects diagnosed at older ages. However, little information is available on the rates of additional anomalies detected after birth or on the ages at which such anomalies are diagnosed. The aims of this work were to describe the initial diagnoses of oral clefts, isolated or associated with other defects, in newborn infants ascertained in hospitals of the ECLAMC network, and diagnostic changes that occurred due to detection of additional defects during a 1-year follow-up period. Seven hundred ten liveborn infants with cleft lip only (CLO), cleft lip with cleft palate (CLP), or cleft palate (CP) were ascertained between 2003 and 2005. Prevalence estimates of isolated and associated (ASO) clefts, diagnoses in infants with associated clefts, and the percentage of isolated clefts that were reclassified as associated were established. Birth prevalence estimates (per 1,000) were as follows: Total: 1.7; CLP: 0.94 (ASO = 23.5%); CP: 0.46 (ASO = 42.3%); CLO: 0.28 (ASO = 7.6%). Initial diagnoses in infants with associated clefts included 38 infants with chromosomal abnormalities, 33 with non-chromosomal syndromes, 16 with malformation sequences, and 98 with multiple anomalies of unknown etiology. Seven percent of newborns initially classified as isolated were later reclassified as associated. Ten infants without associated defects or clinically suspected syndromes were diagnosed as syndromic only through laboratory findings or family history, illustrating the difference between the terms associated versus isolated, which refers to presence or absence of associated anomalies, and syndromic versus non-syndromic, which refers to etiology.

Preferential associations between oral clefts and other major congenital anomalies

OBJECTIVES

To identify preferential associations between oral clefts (CL = cleft lip only, CLP = cleft lip with cleft palate, CP = cleft palate) and nonoral cleft anomalies, to interpret them on clinical grounds, and, based on the patterns of associated defects, to establish whether CL and CLP are different conditions.

DESIGN AND SETTINGS

Included were 1416 cleft cases (CL = 131, CLP = 565, CP = 720), among 8304 live- and stillborn infants with multiple congenital anomalies, from 6,559,028 births reported to the International Clearinghouse for Birth Defects Surveillance and Research by 15 registries between 1994 and 2004. Rates of associated anomalies were established, and multinomial logistic regressions applied to identify significant associations.

RESULTS

Positive associations with clefts were observed for only a few defects, among which anencephaly, encephaloceles, club feet, and ear anomalies were the most outstanding. Anomalies negatively associated with clefts included congenital heart defects, VATER complex (vertebral defects, imperforate anus, tracheoesophageal fistula, and radial and renal dysplasia), and spina bifida.

CONCLUSION

The strong association between all types of clefts and anencephaly seems to be attributable to cases with disruptions; the association between CP and club feet seems to be attributable to conditions with fetal akinesia. Some negative associations may depend on methodologic factors, while others, such as clefts with VATER components or clefts with spina bifida, may depend on biological factors. The different patterns of defects associated with CL and CLP, indicating different underlying mechanisms, suggest that CL and CLP reflect more than just variable degrees of severity, and that distinct pathways might be involved.

5-Bromo-2'-deoxyuridine is selectively toxic to neuronal precursors in vitro

The effect of 5-bromo-2'-deoxyuridine (BrdU) incorporation on the phenotype of progeny derived from expanded E18 rat striatal precursors was examined. BrdU was administered to cultures for 24 h prior to differentiation. Results revealed that there was selective toxicity of this compound to developing TuJ1+ neurons, but not glia, at concentrations used in most labelling studies. Therefore, a BrdU dose-response curve from 0.2 microM to 10 microM was established. The optimum dose of BrdU for labelling cells was 0.2 microM, well below the 1-10 microm recommended concentration. This dose resulted in the survival of significantly more newborn BrdU/TuJ1+ double-labelled neurons and eliminated the toxic effects of BrdU. Administration of 10 microm BrdU resulted in a significant decrease in extracellular regulated kinase (ERK) phosphorylation compared with untreated cultures, this could be completely restored by the administration of either N-methyl-D-aspartate (NMDA) receptor antagonists such as MK801 or the nitric oxide synthesis inhibitor L-methyl-arginine methyl ester (L-NAME). Our results show that high levels of BrdU are selectively toxic to neurons through a mechanism that activates classical cell death pathways. This has implications for labelling studies both in vivo and in vitro.