[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.

[Clinical features of 123 patients with hyperinsulinemic hypoglycemia auxiliarily diagnosed by 18F-DOPA-PET CT scanning].

Objective: To summarize the clinical features and therapeutic outcomes of patients with hyperinsulinemic hypoglycemia (HH) auxiliarily diagnosed by 18F-DOPA positron emission tomography (PET) CT scanning. Methods: The clinical data of 123 patients who were diagnosed with hyperinsulinemic hypoglycemia by comprehensive clinical diagnostic procedures in the Department of Pediatric Endocrinology and Inherited Metabolic Diseases, Children's Hospital of Fudan University between January 2016 and December 2020 were retrospectively analyzed. Clinical data such as gender, age of onset, province, concurrent serum insulin level measured during hypoglycemia, lesion type of pancreas by 18F-DOPA-PET CT scanning, genetic test results, and treatment were collected successively. The clinical features and therapeutic outcomes were compared between patients with focal and diffuse pancreatic lesions. T test, Rank sum test, and χ² test were used for comparison between groups. Results: A total of 123 patients with hyperinsulinemic hypoglycemia (72 males and 51 females), whose average age of onset was 3 days (ranging from 1 day to 4 860 days), were recruited from 24 provinces. The concurrent serum insulin level was 7.1 (0.4-303.0) mU/L during hypoglycemia. 18F-DOPA-PET CT scanning identified focal lesions in 25.2% (31/123) and diffuse lesions in 74.8% (92/123) of the patients; 64.2% (79/123) of the HH cases were found to have pathogenic gene variants, in which 88.6% (70/79) were found to have KATP channel related genes (61 in ABCC8 and 9 in KCNJ11 mutations). Thirty-seven patients (17 focal and 20 diffuse) received surgical treatment with a success rate of 67.6% (25/37). The effective rate of diazoxide for children with diffuse type was significantly higher than that of children with focal group (28.3% (26/92) vs. 9.7% (3/31), χ²=10.31, P=0.001). Conclusions: 18F-DOPA-PET CT scan can improve the success rate of surgery. Comprehensive diagnosis of the etiology of hyperinsulinemic hypoglycemia by genetic analysis and 18F-DOPA-PET CT scanning can result in better treatment and prognosis.

[Feasibility of domestic (18)F-DOPA PET/CT scanning in the differential diagnosis of pancreatic lesions in children with hyperinsulinemic hypoglycemia].

Objective: To study the feasibility of (18)F-fluoro-L-dihydroxyphenylalanine positron emission tomography/Computed tomography ((18)F-DOPA PET/CT) scanning in the localization and differential diagnosing of focal versus diffuse form of pancreas lesions in patients with hyperinsulinemic hypoglycemia (HH). Method: Twenty-four patients were diagnosed with HH between January, 2016 and February, 2017 in the Department of Pediatric Endocrinology and Inherited Metabolic Diseases, Children's Hospital of Fudan University using an integrated clinical and biochemical diagnostic protocol, domestic (18)F-DOPA PET/CT imaging technique were applied after MRI and ultrasound failed to detect pancreas lesions. Pancreas (18)F-DOPA standardized uptake values (SUV) were measured, and pancreas' lesions were dually analyzed via visual method and pancreas percentage SUV method. Among these patients, 9 patients received surgical pancreatic lesion resections, the correlations among surgical outcomes, histopathological findings and (18)F-DOPA PET/CT scan results were analyzed. Result: Seven patients were detected with focal form of pancreas lesions, the mean peak of SUV was 4.7±1.7(2.6-7.1), and 17 patients were found to have diffuse form lesions after (18)F-DOPA-PET/CT scanning. Among the 24 cases, 9 patients (7 showed focal and 2 showed diffuse (18)F-DOPA PET/CT pancreatic uptake)were euglycemic without any medical support after surgery; the resected pancreatic tissue histopathological results were consistent with that of PET/CT imaging. Only one patient, who responded to medical treatment before surgery, had temporary hyperglycemia after operation. Conclusion: Domestic (18)F-DOPA PET/CT could successfully locate and differentiate the pancreatic lesions and thus improve the success of surgery.

Isolation, proliferation, and induction of Bama mini-pig spermatogonial stem cells in vitro.

Spermatogonial stem cells (SSCs), the unique seed cells of testes, can undergo meiosis and form spermatozoa, thus transmitting genetic information to offspring. Research concerning these cells explores the mechanism underlying spermatogenesis, making possible the induction of their differentiation into spermatozoa in vitro. SSCs have therefore attracted much interest among scientists. Although the proliferation of such cells in vitro has been demonstrated, we are unaware of any long-term laboratory culture of porcine SSCs. The objective of this study was to isolate, characterize, culture, and induce the differentiation of Bama mini-pig SSCs. SSCs were isolated using differential plating and cultured for over 100 days on an STO feeder cell layer without serum. Cell clusters appeared after three passages and continuously formed during subsequent cultivation. Staining showed that these clusters were positive for UCHL1 and CDH1, could be bound by Dolichos biflorus agglutinin, and that some cells expressed OCT4. Ultrastructure observations revealed SSCs in testis tissue to be round in shape, while those cultured in vitro were flat and bound together. Our attempts at inducing differentiation showed that SSCs cultured in vitro could undergo meiosis. In this study, we describe an effective culture system for Bama mini-pig SSCs capable of producing enough cells to establish a platform for further SSC research, such as genetic manipulation or exploration of the mechanism underlying spermatogenesis.

Targeting exogenous GDNF gene to the bovine somatic cell beta-casein locus for the production of transgenic bovine animals.

Considerable attention is currently being directed toward methods for producing recombinant human proteins in the mammary glands of genetically modified transgenic livestock. However, the expression of inserted genes in transgenic animals is variable and often very low because of the randomness of the site of transgene integration. One possible strategy to avoid the expression problem associated with random integration is to use site-specific integration by targeting integration to a high expression locus and, thereby, to improve expression of the transferred gene. In the present study, we focused on glial cell line-derived neurotrophic factor (GDNF), a novel type of neurotrophic factor first cloned in 1993. Research has shown that GDNF may have potential applications in the treatment of Parkinson's disease and other diseases of the central nervous system since it acts as a protective factor for central dopaminergic neurons. Here, we constructed a gene targeting vector to knock-in the human GDNF gene at the bovine beta-casein gene locus as a first step to producing transgenic animals with a high level of expression of human GDNF protein in their mammary glands. Bovine fetal fibroblast cells were transfected with linearized pNRTCNbG by electroporation. Three cell clones were identified with successful targeting to the beta-casein locus; and were confirmed using both polymerase chain reaction analysis and sequencing. Gene-targeted cells were used as nuclear donors; a total of 161 embryos were reconstructed, 23 of which developed to the blastocyst stage. These blastocysts were transferred to 8 recipient cows, but no offspring were obtained.

Antibody preparation and identification of the Cashmere goat c-kit protein in the testes.

The c-kit protein plays a major role in the regulation of germ cell development. Its expression and distribution in rodent testes have been widely reported. However, research regarding c-kit expression in domestic animals is scarce, and the expression pattern and distribution of c-kit in germ cells have not been clearly defined. In this study, a specific antigenic region for goat c-kit was designed, and a c-kit polyclonal antibody was prepared. This antibody was then applied in a study evaluating c-kit expression in Cashmere goat tissues. A Western blot analysis showed that three forms of c-kit were expressed in goat testes: precursor, mature, and soluble c-kit. Fluorescent immunohistochemical analyses showed that c-kit was primarily expressed in the spermatogonia and spermatocytes of goat testes. These results not only clarify the expression and localization of c-kit in the goat testis, but also accelerate further research regarding the function of c-kit in goat spermatogenesis.

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.

Gene expression profiling of rat testis development during the early post-natal stages.

Spermatogenesis is a complex biological process that requires precise regulation of gene expression in the germ cells and their surrounding somatic cells. Some testis-specific genes are involved in different stages of spermatogenesis; however, the precise mechanisms of stage-specific spermatogenesis are still not elucidated. In this study, we first examined the expression patterns of SYCP3, Tnp2, CDH1, glial cell-line-derived neurotropic factor (GDNF) and GFRA1 mRNAs on post-natal days (PNDs) 2, 4, 6, 8, 10, 12, 15, 20, 25 and 30 in rat testis. SYCP3 mRNA was firstly detected from PND 15, while Tnp2 transcript was only found on PND 30. CDH1 mRNA was highly expressed before PND 6, but decreased dramatically on PND 8, then gradually increased until it started to decrease after 12 dpp. Low GDNF and GFRA1 mRNAs were found before PND 6, but gradually increased to the peak on PND 12, then gradually decreased to low level. According to the expression patterns of CDH1, GDNF and GFRA1, we hypothesized that PNDs 6-10 are critical period in the early spermatogenesis. We, therefore, explored gene expression pattern on PNDs 6, 8 and 10 using cDNA microarray. 700 (PND 8 vs PND 6), 4519 (PND 10 vs PND 8), and 4298 (PND 10 vs PND 6) differentially expressed genes (≥ 2-fold) were identified from the comparisons, which cover thousands of gene ontology categories (GO terms) and hundreds of signalling pathways. High consistency between microarray data and quantative real-time PCR (qRT-PCR) was verified from five genes (LOC686076, Trib3, Cxcl6, LOC682508 and C2cd4d). These data provide more information to understand the precisely regulatory mechanism at the early stage of spermatogenesis.