Experimental study on protection of vitamin B 6 on TCDD-induced palatal cleft formation in the mice

Genetic background and window of exposure contribute to thyroid dysfunction promoted by low-dose exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin in mice

Genetic and environmental factors contribute to thyroid diseases. Although still debated, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is thought to induce thyroid dysfunction in humans and rodents. The data here reported point out the contribution of the exposure window and genetic background in mediating the low-dose TCDD effects on thyroid. Indeed, early (from E0.5 to PND30) and low-dose (0,001 μg/kg/day) TCDD exposure reduced the circulating fT4 and altered the expression of thyroid specific transcripts. The role of genetic components was estimated monitoring the same markers in Pax8^+/- and Nkx2-1^+/- mice, susceptible to thyroid dysfunction, exposed to 0, 1 μg/kg/day TCDD from E15.5 to PND60. Haploinsufficiency of either Pax8 or Nkx2-1 genes exacerbated the effects of the exposure impairing the thyroid enriched mRNAs in sex dependent manner. Such effect was mediated by mechanisms involving the Nkx2-1/p53/p65/IĸBα pathway in vitro and in vivo. Foetal exposure to TCDD impaired both thyroid function and genes expression while thyroid development and differentiation did not appear significantly affected. In mouse, stronger effects were related to earlier exposure or specific genetic background such as either Pax8 or Nkx2-1 haploinsufficiency, both associated to hypothyroidism in humans. Furthermore, our data underline that long exposure time are needed to model in vitro and in vivo results.

Palm and finger print characteristics in nonfamilial cleft lip and palate patients and their parents

The aim of this study was to investigate if Iranian individuals with nonfamilial cleft lip and palate (CLP) and their unaffected parents display more dermatoglyphic asymmetry than the normal population.The study group included 55 patients with nonfamilial CLP and their unaffected parents (38 fathers and 47 mothers). The control group included 60 healthy children and their parents (37 fathers and 50 mothers). Total ridge counts of each finger (TRC), atd angles, a-b ridge counts, and finger print pattern types of all participants were recorded. Asymmetry between the right and left hands of each individual was determined. Dissimilarity between pattern types on homologous fingers was compared using chi-square test. Asymmetry of other parameters was statistically analyzed using the Mann-Whitney U test.There were no significant differences between the groups in terms of their asymmetry of atd angle, a-b ridge count, and pattern dissimilarity score. However, significant differences in mean TRC between CLP patients and control children were found for the right ring digit (P = 0.023), right little digit (P = 0.032), and left index digit (P = 0.005). Also, there were significant differences among CLP patients and control children (P = 0.022) as well as unaffected fathers of CLP patients and their control group (P = 0.020) in terms of type of finger print pattern.No enhanced fluctuating asymmetry was found in most of the dermatoglyphic traits in the population studied, which indicated a low degree of developmental instability of the sporadic cases of cleft deformity.

Prevalence of dental anomalies in patients with cleft lip and palate

The aim of the present study was to investigate the prevalence of dental anomalies in a group of patients with cleft lip and palate (CL/P) in the northeast of Iran. Ninety-one patients referring to the Cleft Lip and Palate Clinic of Mashhad Dental School were enrolled and classified into right CL/P, left CL/P, and bilateral CL/P groups. Photographs, dental casts, and panoramic and periapical radiographs were retrieved, and dental anomalies were recorded. χ test was used to analyze the frequency of dental anomalies according to type of cleft and sex. Missing maxillary lateral incisors was the most frequent dental anomaly, which was slightly higher in the bilateral group (61.1%). There were significantly more cases of missing lateral incisors outside the cleft area in right CL/P (P = 0.015). Peg lateral incisors were observed in 33.3% of bilateral CL/P compared with 28% of right and 23.3% of left unilateral cases. The sample presented rotations of central incisors in the cleft area in 33.3% of bilateral clefts. In unilateral clefts, it occurred more frequently in the right side (48%). Sexual dimorphism appeared only for maxillary central incisor rotation in the cleft area, which showed significantly greater frequency in females (P = 0.025). Transposition of maxillary canine and first premolars was found in 5.5% of bilateral, 8% of right, and 3.3% of left unilateral clefts. The prevalence of dental anomalies in the studied sample seems to be higher than that reported in the normal population. More anomalies were observed at the cleft side. The frequency of most anomalies was not significantly different between the 2 sexes.