[Relationship between body mass index and sexual development in Chinese children].

Objective: To investigate the relationship between body mass index (BMI) and sexual development in Chinese children. Methods: A nationwide multicenter and population-based large cross-sectional study was conducted in 13 provinces, autonomous regions and municipalities of China from January 2017 to December 2018. Data on sex, age, height, weight were collected, BMI was calculated and sexual characteristics were analyzed. The subjects were divided into four groups based on age, including ages 3-<6 years, 6-<10 years, 10-<15 years and 15-<18 years. Multiple Logistic regression models were used for evaluating the associations of BMI with sexual development in children. Dichotomous Logistic regression was used to compare the differences in the distribution of early and non-early puberty among normal weight, overweight and obese groups. Curves were drawn to analyze the relationship between the percentage of early puberty and BMI distribution in girls and boys at different Tanner stages. Results: A total of 208 179 healthy children (96 471 girls and 111 708 boys) were enrolled in this study. The OR values of B2, B3 and B4+ in overweight girls were 1.72 (95%CI: 1.56-1.89), 3.19 (95%CI: 2.86-3.57), 7.14 (95%CI: 6.33-8.05) and in obese girls were 2.05 (95%CI: 1.88-2.24), 4.98 (95%CI: 4.49-5.53), 11.21 (95%CI: 9.98-12.59), respectively; while the OR values of G2, G3, G4+ in overweight boys were 1.27 (95%CI: 1.17-1.38), 1.52 (95%CI: 1.36-1.70), 1.88 (95%CI: 1.66-2.14) and in obese boys were 1.27 (95%CI: 1.17-1.37), 1.59 (95%CI: 1.43-1.78), and 1.93 (95%CI: 1.70-2.18) (compared with normal weight Tanner 1 group,all P<0.01). Analysis in different age groups found that OR values of obese girls at B2 stage and boys at G2 stage were 2.02 (95%CI: 1.06-3.86) and 2.32 (95%CI:1.05-5.12) in preschool children aged 3-<6 years, respectively (both P<0.05). And in the age group of 6-10 years, overweight girls had a 5.45-fold risk and obese girls had a 12.54-fold risk of B3 stage compared to girls with normal BMI. Compared with normal weight children, the risk of early puberty was 2.67 times higher in overweight girls, 3.63 times higher in obese girls, and 1.22 times higher in overweight boys, 1.35 times higher in obese boys (all P<0.01). Among the children at each Tanner stages, the percentage of early puberty increased with the increase of BMI, from 5.7% (80/1 397), 16.1% (48/299), 13.8% (27/195) to 25.7% (198/769), 65.1% (209/321), 65.4% (157/240) in girls aged 8-<9, 10-<11 and 11-<12 years, and 6.6% (34/513), 18.7% (51/273), 21.6% (57/264) to 13.3% (96/722), 46.4% (140/302), 47.5% (105/221) in boys aged 9-<10, 12-<13 and 13-<14 years, respectively. Conclusions: BMI is positively correlated with sexual development in both Chinese boys and girls, and the correlation is stronger in girls. Obesity is a risk factor for precocious puberty in preschool children aged 3-<6 years, and 6-<10 years of age is a high risk period for early development in obese girls.

[Survey of height and weight of children and adolescents at different Tanner stages in urban China].

Objective: To investigate the status of height and weight of 3-18-year-old children and adolescents in urban China, and to provide a basis for establishing puberty phase specific curves for age-specific height and age-specific weight. Methods: A cross-sectional survey of 218 185 children and adolescents aged 3-18 years in urban China was conducted by using the method of stratified random cluster sampling from January 2017 to December 2019. The sampling areas included 12 provinces municipalities in China and autonomous regions in total. Data were collected on weight, height, waist circumference, hip circumference and secondary sexual characteristics. The generalized additive model for location, scale, and shape (GAMLSS) was employed to establish percentile reference values and growth curves of height and weight for boys and girls aged 3-18 years. Wilcoxon rank sum test was applied to compare the P50 value of height and weight between children of each Tanner stage and children of the same age ignoring the different puberty phase. Results: The 3rd, 50th, and 97th percentile curves for height and weight for age were developed for boys and girls aged 3-18 years. The 3rd, 50th, and 97th percentile curves for age-specific height and age-specific weight for each puberty phase were developed for boys and girls. Compared with all children ignoring the different puberty phase, boys aged 9 and over and girls aged 7 and over who are at Tanner stage 1 showed shorter height and lighter weight than those of the same age group (all P<0.01), the difference ranges of height at P50 are -4.0 to -0.6 cm for boys, and -4.4 to 0.5 cm for girls; the difference ranges of weight are -4.8 to 0.4 kg for boys, and -4.0 to -0.3 kg for girls; children at Tanner stage 2 & 3 initially were taller and heavier than those of the same age group; and later grew shorter and lighter than those of the same age group, the two sets of curves cross over; boys aged 16 and under and girl aged under 14 who are at Tanner stage 4 were taller and heavier than those of the same age group (all P<0.01), the difference ranges of height at P50 are 0.2 to 10.0 cm for boys, and 0.2 to 9.4 cm for girls; the difference ranges of weight at P50 are 0.7 to 10.9 kg for boys, and 1.0 to 11.2 kg for girls, and the differences showed narrowing trend with age. Conclusion: The puberty phase specific growth curves of age-specific height and age-specific weight for boys and girls aged 3-18 years are established, it is useful for clinical work to evaluate physical development of children at different puberty phases.

[Changing prevalence of overweight and obesity among Chinese children aged 6-15 from 2009-2019].

Objective: To analyze the trends of overweight and obesity prevalence in Chinese children, aged from 6 to 15 years old among 4 provinces and cities from 2009 to 2019. Methods: Reviewed the national multi-center epidemiological survey data of children from the National Key Technology R&D Program of China during the Eleventh Five-Year Plan (2009 to 2010) and the National Key Research and Development Program of China during the Thirteenth Five-Year Plan (2017 to 2019). The participants' data were selected from four provinces,municipalities and autonomous region,including Beijing, Tianjin (Northern region), Zhejiang (Eastern region), and Guangxi (Southern region). Totally 14 597 pairs of 6-15 year-old children were surveyed. According to the body mass index (BMI) and standard deviation score (SDS) of children among different genders, ages, and regions, t test or chi-square test was used to evaluate the changes in overweight and obesity over a 10-year span. Results: Totally 7 721 pairs of boys and 6 876 pairs of girls were collectted in this study, whose mean age was (10.7±2.5) years. In the past 10 years, the overall BMISDS were 0.39±1.24 and 0.36±1.31 and the overall obesity rate were 11.8% (n=1 773) anel 12.5% (n=1 813) of children in the 4 administrative regions did not have statistically significant differences (all P>0.05). However, the overall overweight rate rose from 17.1% (n=2 496) to 19.1% (n=2 781) (χ²=18.657, P<0.01), and the average annual growth rate was 0.20%. The BMISDS in the Eastern region increased from 0.10±1.07 to 0.19±1.22 (t=-4.095, P<0.01), and the overweight rate and obesity rate increased by 3.8% (n=202) and 3.1% (n=169) respectively (both P<0.01); the BMISDS in the Northern region and the obesity rate did not have statistically significant differences(all P>0.05), but the overweight rate rose from 20.5% (n=1 233) to 22.8% (n=1 365) significantly (χ²=7.431, P<0.01); BMISDS in the Southern region was significantly decreased from 0.30±1.19 to 0.09±1.25 (t=1.426, P<0.01), and the rate of obesity decreased from 9.8% (n=315) to7.9% (n=256) (χ²=6.46, P<0.05), the overweight rate was not stafistically significant (P=0.10), respectively. The obesity rate of boys had risen from 16.4% (n=1 265) to 18.2% (1 407) (χ²=8.997, P<0.01) in the past 10 years, and the overweight rate had risen from 18.0% (n=1 393) to 20.5% (n=1 579) (χ²=14.26, P<0.01). The overweight+obesity rate rose from 34.4% (n=2 658) to 38.7% (n=2 986) (χ²=29.859, P<0.01), and the weight problem in the age group of 8 to 11 years was particularly severe (all P<0.01). The obesity rate of girls dropped from 6.8% (n=468) to 5.9% (n=406) (χ²=4.546, P<0.05), the overweight rate rose from 16.0% (n=1 103) to 17.5% (n=1 202) (χ²=5.006, P<0.05), and the overall overweight+obesity rate rose from 22.8% (n=1 571) to 23.4% (n=1 608) (χ²=0.53, P>0.05). Conclusions: The growth rate of obesity among children in China had slowed down from 2009 to 2019, but the overweight rate was still on the rise. The overall base of overweight and obesity population continued to expand. The weight problem of peri-adolescent boys was particularly prominent. The current status of obesity epidemics in different regions, ages, and genders are significantly different and had their own characteristics. It is necessary to establish a personalized prevention and control strategy.

[Research progress in saliva collection, analysis and its relationship with oral diseases].

As one of the major body fluid, saliva has various components that can shift according to the systemic health state. With the atraumatic way of collection, saliva can be a promising media to help the detection of oral diseases. With the development of salivaomics and the application of unbiased, highly sensitive, and high throughout separation techniques for salivary components, there's now more possibilities for effective identification of biomarkers correlated with oral diseases. This review aimed to introduce the current state of saliva collection and detection techniques as well as their correlation with oral diseases, hoping to provide evidence for further research.

[Analysis of four carnitine-acylcarnitine translocase deficiency cases caused by homozygous mutation of SLC25A20 c.199-10T> G].

Objective: To investigate the clinical, biochemical and genetic features of four carnitine-acylcarnitine translocase deficiency cases. Methods: Four cases diagnosed with carnitine-acylcarnitine translocase deficiency from Guangxi Maternal and Child Health Hospital were studied. DNA was extracted from dry blood filter for gene analysis. SLC25A20 gene analysis was performed in 1 case and the whole exon sequence analysis was performed in 3 cases. Results: Retrospective study on unrelated carnitine-acylcarnitine translocase deficiency patients, the age of onset was 1-28 d, the age of death were 1.5-30 d, main clinical features were hypoglycemia (4 cases), arrhythmia (2 cases), sudden death (2 cases). Biochemical test showed hypoglycemia (1.2-2.0 mmol/L) , elevated creatine kinase (955-8 361 U/L) and creatine kinase isozyme(199-360 U/L), normal or decreased free carnitine level (3.70-27.07 µmol/L) , elevated long-chain acylcarnitine (palmityl carnitine 1.85-14.84 µmol/L). The gene tests showed that all 4 cases carried SLC25A20 gene c.199-10T> G homozygous mutation, inherited from their parents. By analyzing the haplotype, we found that the mutation loci of C. 199-10T> G were all in the same haplotype. Conclusion: The c.199-10T> G mutation is an important molecular cause of carnitine-acylcarnitine translocase deficiency, which has relatively high frequency in Guangxi population, and is related to the founder effect.

[Genetic analysis for 5 congenital hypothyroidism patients due to dyshormonogenesis].

OBJECTIVE: To analyze molecular characteristics of 5 congenital hypothyroidism (CH) patients due to dyshormonogenesis. METHOD: We enrolled 5 CH patients due to dyshormonogenesis who were identified in Newborn Screening Center of Guangxi Zhuang Autonomous Region, China. Blood samples were collected from the patients and their parents, and genomic DNA was extracted from peripheral blood leukocytes. All exons of DUOX2, TG, TPO and NIS gene together with their exon-intron boundaries were screened by next-generation sequencing. Specimens from 100 normal controls were tested for these novel variations. RESULT: No TPO, NIS or TG gene mutations were identified. Direct sequencing of the DUOX2 gene revealed that patient 1 had a compound heterozygote for c. 3340delC and p. R683L, patient 2 was homozygous for p. K530X and patient 3 was a heterozygote for p. E879K. Both biallelic and monoallelic heterozygous mutations in DUOX2 were associated with transient CH. Novel mutations included c. 3340delC and p. R683L, analysis of 100 healthy subjects without thyroid disease did not show the same change. CONCLUSION: Genetic analysis of TPO, NIS, DUOX2 and TG gene in 5 unrelated CH patients with thyroid dyshormonogenesis revealed two novel DUOX2 mutations, both were biallelic and monoallelic heterozygous mutations in DUOX2 associated with transient CH.

In-vitro Activity of Honey and Topical Silver in Wound Care Management.

BACKGROUND: With the rise of multidrug resistance among pathogens, especially in wound care management is of great concern. Hence, we designed to study the in-vitro activity of topical agents honey and silver against wound infection and compares silver and honey dressings used in wound care. METHODS: 172 isolates from burn and surgical wounds were isolated from patients admitted to Nursing College, Changchun University Of Chinese Medicine, China during 2013-2014 are included in the study. 59 Pseudomonas, 41 E.coli, 28 S aureus, 25 Klebsiella pneumoniae, 11 Proteus, 8 Acinetobacter were isolated. Susceptibility testing for honey and silver nitrate was done using the agar dilution method. 80 patients were divided into 2 groups. Type 1 used Algivon with UMF12 honey coated dressing for 40 patients and the other 40 patients received Type II used Acti-coat silver absorbent dressings. 30 patients received ordinary dressings were included as control group patients. RESULTS: 50/59 (84.7%) Pseudomonas spp, 39 (95.1%) of E.coli and 26/28 (92.9%) S. aureus were sensitive for silver nitrate. K. pneumoniae, Proteus spp and Acinetobacter spp showed 100% sensitivity for silver nitrate by agar dilution method. All the isolates showed 100% sensitivity for honey at concentration. In type I - honey coated dressings consist of 40 patients with 18 (45%) male and 22 (55%) female patients. Type II - silver-coated dressings consist of 40 patients with 24 (60%) females and 16 (40%) male patients. CONCLUSION: This study results showed positive efforts on improvising in wound dressings as a replacement to lower antimicrobial resistance and limit racial use of antibiotics.

Association between obesity and sexual maturation in Chinese children: a muticenter study.

OBJECTIVE: We aimed to evaluate the current status of sexual maturation of Chinese children, to examine the association between obesity and early sexual maturation in boys and compare it with girls and to test the hypothesis that the associations differ by gender. STUDY DESIGN: Cross-sectional study. SUBJECTS: A representative sample involving 9812 boys and 8895 girls aged 6-18 years who participated in the Chinese Children and Adolescent Metabolic Syndrome Epidemiologic Study (July 2009- July 2010) were surveyed. METHODS: All subjects had complete anthropometry and sexual maturation data. SUBJECTS who reached Tanner stage 2 or more (5601 boys and 6538 girls) were divided into tertiles based on the timing of sexual maturation. The subjects in the earliest tertile were included into the early-maturing group, and the middle tertile and the latest tertile into the not early-maturing group. Overweight was defined as a body mass index (BMI) ⩾85th percentile and obesity ⩾95th percentile. Logistic regression analysis was used to test how early maturation affected the risk of overweight. Multiple linear regression was used to examine the association between fatness (BMI Z-score) and sexual maturation. RESULTS: Slightly more boys were obese than girls (P<0.01). The median age for girls of the Tanner stage 2 was 9.69 years, and for boys of Tanner stage 2 was 11.25 years. BMI Z-score were higher (P<0.01) in both early-maturing girls and boys, compared with the non-early maturers, respectively. Early sexual maturation was positively associated with obesity in both girls and boys. With covariates adjusted and using non-early maturing as the reference group, odds ratios for combined overweight were 1.48 for boys and 2.64 for girls, and for obesities were 1.61 for boys and 3.49 for girls, respectively. CONCLUSION: Obesity is positively associated with sexual maturation in both boys and girls, and the association does not differ by gender, but the association is stronger in girls than in boys.

Implication of transcriptional repression in compound C-induced apoptosis in cancer cells.

Compound C, a well-known inhibitor of AMP-activated protein kinase (AMPK), has been reported to induce apoptosis in some types of cells. However, the underlying mechanisms remain largely unclear. Using a DNA microarray analysis, we found that the expression of many genes was downregulated upon treatment with compound C. Importantly, compound C caused transcriptional repression with the induction of p53, a well-known marker of transcriptional stress response, in several cancer cell lines. Compound C did not induce the phosphorylation of p53 but dramatically increased the protein level of p53 similar to some other transcriptional inhibitors, including 5,6-dichloro-1-ß-D-ribobenzimidazole (DRB). Consistent with previous reports, we found that compound C initiated apoptotic death of cancer cells in an AMPK-independent manner. Similar to DRB and actinomycin D (ActD), two classic transcription inhibitors, compound C not only resulted in the loss of Bcl-2 and Bcl-xl protein but also induced the phosphorylation of eukaryotic initiation factor-alpha (eIF2α) on Ser51. Hence, the phosphorylation of eIF2α might be a novel marker of transcriptional inhibition. It is noteworthy that compound C-mediated apoptosis of cancer cells is correlated with decreased expression of Bcl-2 and Bcl-xl and the phosphorylation of eIF2α on Ser51. Remarkably, compound C exhibits potent anticancer activities in vivo. Taken together, our data suggest that compound C may be an attractive candidate for anticancer drug development.

Unfolded protein response suppresses cisplatin-induced apoptosis via autophagy regulation in human hepatocellular carcinoma cells.

It has been shown that drug resistance is extremely common in hepatocellular carcinoma (HCC) and is one of the major problems in HCC chemotherapy. However, the detailed mechanisms remain largely unknown. We have previously shown that endoplasmic reticulum (ER) stress is involved in the tumorigenesis of HCC. Here, we demonstrated that the unfolded protein response (UPR) inhibits cisplatin-induced HCC cell apoptosis. In HCC cells, cisplatin treatment triggers the UPR, which subsequently inhibits cisplatin-induced apoptosis. Importantly, mild ER stress precondition suppresses the sensitivity of HCC cells to cisplatin-induced apoptosis through autophagy regulation. Furthermore, heat-shock protein 27 (Hsp27) is involved in the cytoprotective role of the UPR in cisplatin-induced apoptosis. We also demonstrated that Hsp27 inhibits cisplatin- induced HCC cell death through autophagy activation. Taken together, our results indicate that the UPR inhibits cisplatin-induced apoptosis in HCC cells, at least in part, by Hsp27-mediated autophagy activation.

Photoentrainment and pupillary light reflex are mediated by distinct populations of ipRGCs.

Intrinsically photosensitive retinal ganglion cells (ipRGCs) express the photopigment melanopsin and regulate a wide array of light-dependent physiological processes. Genetic ablation of ipRGCs eliminates circadian photoentrainment and severely disrupts the pupillary light reflex (PLR). Here we show that ipRGCs consist of distinct subpopulations that differentially express the Brn3b transcription factor, and can be functionally distinguished. Brn3b-negative M1 ipRGCs innervate the suprachiasmatic nucleus (SCN) of the hypothalamus, whereas Brn3b-positive ipRGCs innervate all other known brain targets, including the olivary pretectal nucleus. Consistent with these innervation patterns, selective ablation of Brn3b-positive ipRGCs severely disrupts the PLR, but does not impair circadian photoentrainment. Thus, we find that molecularly distinct subpopulations of M1 ipRGCs, which are morphologically and electrophysiologically similar, innervate different brain regions to execute specific light-induced functions.

Pubertal development timing in urban Chinese boys.

We describe current pubertal development in healthy urban Chinese boys. A cross-sectional study of the pubertal development of 18,807 urban Chinese boys aged from 3.50 to 18.49years was conducted between 2003 and 2005. Testicular volume was evaluated with a Prader orchidometer. Pubic hair development was assessed according to the Tanner method. Data on spermarche were collected using the status quo method. Probit analysis was used to calculate the median age and 95% CI at different stages of testicular development, pubic hair development and spermarche. By age 9, 12.99% of the boys had a testicular volume of 4mL or greater. The median age of onset of puberty defined as the age at attainment of testicular volume of 4mL or greater was 10.55 (95% CI 10.27-10.79) years. The median age for onset of pubic hair development (PH(2) ) and spermarche was 12.78 (95%CI 12.67-12.89) years and 14.05 (95%CI 13.80-14.32) years, respectively. Pubertal onset in urban Chinese boys is earlier than currently used clinical norms but their pubic hair development occurs relatively late in comparison with the reported data from numerous other countries. There is also evidence of a secular trend towards an earlier age of spermarche since 1979 in Chinese urban boys.

PI3K/Akt promotes GRP78 accumulation and inhibits endoplasmic reticulum stress-induced apoptosis in HEK293 cells.

The potential pro-survival role of phosphatidylinositol 3-kinase (PI3K)/Akt during endoplasmic reticulum stress has been well-characterized. However, the detailed mechanisms remain largely unknown. Here, we showed that PI3K/Akt inhibition promoted endoplasmic reticulum stress-induced apoptosis in a glucose-regulated protein 78 (GRP78)-dependent manner. During endoplasmic reticulum stress, high levels of Akt phosphorylation were sustained for at least 18 h in HEK293 cells. Importantly, PI3K/Akt enhanced GRP78 accumulation through increasing its stability following endoplasmic reticulum stress. Furthermore, Akt1, but not Akt2 or Akt3, was involved in GRP78 stability regulation. These results suggest that PI3K/Akt inhibits endoplasmic reticulum stress-induced apoptosis in HEK293 cells, at least in part, by promoting GRP78 protein stability.

The association of homeobox gene expression with stem cell formation and morphogenesis in cultured Medicago truncatula.

Somatic embryogenesis (SE) is induced in vitro in Medicago truncatula 2HA by auxin and cytokinin but rarely in wild type Jemalong. The putative WUSCHEL (MtWUS), CLAVATA3 (MtCLV3) and the WUSCHEL-related homeobox gene WOX5 (MtWOX5) were investigated in M. truncatula (Mt) and identified by the similarity to Arabidopsis WUS, CLV3 and WOX5 in amino acid sequence, phylogeny and in planta and in vitro expression patterns. MtWUS was induced throughout embryogenic cultures by cytokinin after 24-48 h and maximum expression occurred after 1 week, which coincides with the induction of totipotent stem cells. During this period there was no MtCLV3 expression to suppress MtWUS. MtWUS expression, as illustrated by promoter-GUS studies, subsequently localised to the embryo, and there was then the onset of MtCLV3 expression. This suggests that the expression of the putative MtCLV3 coincides with the WUS-CLAVATA feedback loop becoming operational. RNAi studies showed that MtWUS expression is essential for callus and somatic embryo production. Based on the presence of MtWUS promoter binding sites, MtWUS may be required for the induction of MtSERF1, postulated to have a key role in the signalling required for SE induced in 2HA. MtWOX5 expressed in auxin-induced root primordia and root meristems and appears to be involved in pluripotent stem cell induction. The evidence is discussed that the homeobox genes MtWUS and MtWOX5 are "hijacked" for stem cell induction, which is key to somatic embryo and de novo root induction. In relation to SE, a role for WUS in the signalling involved in induction is discussed.

Associations between VHL genotype and clinical phenotype in familial von Hippel-Lindau disease.

BACKGROUND: Von Hippel-Lindau (VHL) disease is an autosomal dominant hereditary disorder associated with tumours and cysts in the central nervous system (CNS) and other visceral organs. Germline mutations in the VHL gene on chromosome 3p25-26 are considered the cause of this disease. MATERIALS AND METHODS: We studied six patients with VHL disease and their relatives. Loss of heterozygosity (LOH) was determined by five flanking microsatellite polymorphic markers in the VHL locus. Multiplex ligation-dependent probe amplification (MLPA) and quantitative real-time polymerase chain reaction (qPCR) amplification were used to detect the genomic deletions. Single-strand conformation polymorphism (SSCP) analysis was applied to test for sequence variations. RESULTS: Three germline deletions in the VHL gene (142.9, 53.3 and 3.3 kb) were found by MLPA. These deletions were defined clearly by qPCR analyses. The142.9 kb germline deletion was significantly associated with patients with CNS haemangioblastomas (P < 0.01 by Fisher's exact test), and one missense mutation (Gln209Arg) was detected from a patient with a pancreatic cyst in the same family. LOH was also detected from a patient with bilateral renal cell carcinomas. CONCLUSION: Diverse genetic conditions are associated with the clinical manifestations of VHL disease. Genomic deletions that can be detected by MLPA or qPCR are major causes for this syndrome. Missense mutations and LOH accompanying the disease lead to complex clinical symptoms and genotypic determination can facilitate a clinical diagnosis because of their strong association.

Reliability of landmark identification in cephalometric radiography acquired by a storage phosphor imaging system.

OBJECTIVES: To compare the cephalometric landmark identification on softcopy and hardcopy of direct digital cephalography acquired by a storage-phosphor (SP) imaging system. METHODS: Ten digital cephalograms and their conventional counterpart, hardcopy on a transparent blue film, were obtained by a SP imaging system and a dye sublimation printer. Twelve orthodontic residents identified 19 cephalometric landmarks on monitor-displayed SP digital images with computer-aided method and on their hardcopies with conventional method. The x- and y-coordinates for each landmark, indicating the horizontal and vertical positions, were analysed to assess the reliability of landmark identification and evaluate the concordance of the landmark locations in softcopy and hardcopy of SP digital cephalometric radiography. RESULTS: For each of the 19 landmarks, the location differences as well as the horizontal and vertical components were statistically significant between SP digital cephalometric radiography and its hardcopy. Smaller interobserver errors on SP digital images than those on their hardcopies were noted for all the landmarks, except point Go in vertical direction. The scatter-plots demonstrate the characteristic distribution of the interobserver error in both horizontal and vertical directions. Generally, the dispersion of interobserver error on SP digital cephalometric radiography is less than that on its hardcopy with conventional method. CONCLUSIONS: The SP digital cephalometric radiography could yield better or comparable level of performance in landmark identification as its hardcopy, except point Go in vertical direction.

Estimation of single-root surface area from true thickness data and from thickness derived from digital dental radiography.

OBJECTIVES: The prognosis of a tooth affected by periodontitis may depend on the amount of bone remaining around the root surface. The aim of this study was to find how the surface area of a single root is related to the true thickness data and the calculated thickness data from digital dental radiographs. METHODS: Eight extracted single-root teeth were digitized three-dimensionally for direct surface area measurement. Meanwhile, they were also exposed to a digital dental X-ray system. The true thickness of the tooth root was measured. The estimated circumference data were calculated from both the measured thickness and the thickness estimated from the digital image and then measured and estimated circumferences were compared. RESULTS: (1) The largest circumference difference mean for measured thickness and for estimated thickness was -4.94% (+/-0.07%) and 23.02% (+/-1.12%) respectively. (2) The largest 95% confidence interval for difference means for measured thickness and for estimated thickness was (-2.82%, -1.87%) and (-5.42%, 2.22%), respectively. CONCLUSIONS: When the thickness data are available, the surface area of a single-root tooth can be estimated to an error of less than 5%. Theoretically, the root thickness can be derived from the projected radiological image of the tooth. However, the error of estimated circumference from digital dental radiography may be over 20%. This error can be minimized if the estimated thickness from digital dental radiography can be made more accurate.

Management of oral and maxillofacial radiology clinics in Taiwan's dental schools.

OBJECTIVES: To investigate management of Taiwanese dental school Oral and Maxillofacial Radiology (OMFR) clinics and to suggest alternative management strategies. METHODS: A management questionnaire was designed for the faculty responsible for teaching the Oral and Maxillofacial Radiology curriculum. RESULTS: Data from all seven Taiwanese schools indicated inadequate supervision of the prescription of radiological examinations in the absence of guidelines. Most schools are understaffed and not properly equipped. There is a significant shortage of trained dentists in the field of OMFR. In some schools no dentist is involved in the management of OMFR clinics. Some aspects of quality assurance procedures should be enhanced. An average of 21.4% of films were reported lost, with the highest rate at 40%, demonstrating serious problems in image archiving. Clinician satisfaction with clinic management averaged 74.3%, with a minimum of 50%. CONCLUSION: A set of standards is recommended by the Taiwanese OMFR Association after reviewing the survey findings. Prescription for OMFR examination should be supervised by licensed clinicians, and there is a need for guidelines. Trained and dedicated personnel should be assigned for the management of OMFR clinics. More quality assurance procedures should be performed. A computer-based image archiving system is desirable.

The relationship between radiologic interpretation and root tip fracture during tooth extraction performed by junior clinicians.

OBJECTIVES: The purpose of this study was to analyze the relationship between root tip fracture and radiologic interpretation of root morphology on periapical radiographs during third molar extraction performed by junior clinicians. METHODS: Before tooth extraction, periapical radiographs of 107 patients with 116 third molars were evaluated by junior clinicians, all with less than 5 years of clinical experience. Radiologic interpretations of root morphology-including number, curvature, fusion, and accessory root-were recorded before each extraction. The clinicians were also asked to estimate the possibility of root fracture on a Visual Analogue Scale before the procedure. The exact morphology of the extracted teeth was recorded after the extraction for the purpose of comparison. RESULTS: Twenty-nine of 116 teeth extracted were not correctly interpreted in at least 1 of the morphologic categories surveyed. The average expected fracture rate of nonfractured teeth was 23.1%, whereas the average expected fracture rate of fractured teeth was a significantly higher 50.3%. Misinterpretation of root morphology on radiographs decreased with increased clinical experience. Senior residents had the lowest misinterpretation and fracture rate. Logistic regression analysis showed that fracture is most closely related to the estimated fracture rate (4.95) and is also significantly related to underestimation of root curvature (0.95; 24.56 with 2 df of chi-square, P = .0001). CONCLUSIONS: Misinterpretation of root morphology on radiographs occurred in 25% of the teeth. Root curvature was the most misinterpreted item studied. Fracture was most closely related to the estimated fracture rate. Junior clinicians in this study expected that only 50% of the fractured teeth would fracture, reflecting a general underestimation of root tip fracture. Further study should be performed to evaluate how to increase the accuracy of root curvature interpretation.

Determination of 8-oxoguanine in individual cell nucleus of gamma-irradiated mammalian cells.

8-Oxoguanine, through its ability to mispair bases other than cytosine, is assumed to be one of the most potent premutagenic lesions in nuclear DNA damaged by reactive oxygen radicals. In this study, we examine whether the presence of residual 8-oxoguanine can be detected in mammalian cells after exposure to ionizing radiation. MOLT-4 human leukemia cells and CHO-K1 Chinese hamster cells were acutely irradiated in vitro with 0, 0.2, 0.4, 0.6 and 1.0 Gy gamma radiation at room temperature. The amounts of 8-oxoguanine and total DNA in the cell nucleus were detected by fluorescein-isothiocyanate (FITC)-labeled avidin, which binds specifically and directly to 8-oxoguanine, and propidium iodide, respectively. The intensity ratios between these two fluorescent dyes were then taken as indices to measure the content of 8-oxoguanine within individual cells. We found an apparent dose-dependent increase in the amount of 8-oxoguanine accumulated in cells of both lines. Moreover, the content of 8-oxoguanine decreased from 2 to 20 h after irradiation in CHO-K1 cells, which may reflect the time-dependent repair processes at the 8-oxoguanine lesions. This novel approach may provide a sensitive tool for in situ measurement of 8-oxoguanine in cells or even in the human body after exposure to ionizing radiation.