OBJECTIVETo evaluate the incidence of two-rooted mandibular premolar morphology using full-mouth periapical film series in a Chinese population, with particular emphasis on bilateral incidence, so as to provide a clinical anatomical basis for root canal treatment in mandibular premolars.

METHODSA total of 2015 patients who underwent dental treatment and had full mouth periapical radiographs at the Peking University School of Stomatology from April 2011 to April 2012 were enrolled in this study. Three experienced dentists reviewed the patients' periapical films and classified the root morphology of mandibular premolars bilaterally. The incidence of unilateral and bilateral double roots were recorded and calculated, including confirmed and suspected bucco-lingual root types.

RESULTSIn terms of the morphology of two-rooted mandibular first premolars, of the 2015 cases with complete root formation, two-rooted first premolars were detected in 120 cases, with a total number of 159 teeth. According to the number of teeth, the overall incidence of double roots was 4.03% (159/3972). In terms of the morphology of two-rooted mandibular second premolars, of the 2015 cases with complete root formation, two-rooted second premolars were detected in 24 cases, with a total number of 33 teeth. According to the number of teeth, the overall incidence of double roots was 0.85% (33/3880).

CONCLUSIONSThe roots of mandibular premolars display specific morphological patterns. Based on a large sample, we observed and calculated not only the occurrence rate of bucco-lingual and mesio-distal double roots in first and second mandibular premolars, but also the incidence of unilateral or bilateral double roots within the same mandible. These findings could provide useful information on the anatomical structure of mandibular premolars for endodontic, prosthodontic and surgical procedures, and could improve the quality of treatment and reduce complications.

Adolescent ; Adult ; Aged ; Bicuspid ; abnormalities ; Child ; Humans ; Mandible ; Middle Aged ; Periapical Tissue ; diagnostic imaging ; Radiography ; Tooth Root ; abnormalities

Background：In November 2012, an outbreak of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) skin and soft tissue infections affecting students at a boarding school in Hong Kong Special Administrative Region (China) was detected.Methods：A case was defined as any student or staff notified with MRSA infection from 25 October 2012 to 5 July 2013 with the clinical isolate being of staphylococcal cassette chromosome mec type IV or V and positive for Panton-Valentine leukocidin gene. We conducted field investigations, advised on control measures and enhanced surveillance for skin and soft tissue infections at the school. Decolonization therapies were offered to all cases and contacts, and carrier screening was conducted.Results：There were five cases; two (40%) were hospitalized and three (60%) required surgical treatments. Initial screening comprised 240 students and 81 staff members. Overall, four cases (80%) plus eight other students (3.3%) were carriers, with eight of 12 (66.7%) from the same dormitory. All staff members screened negative. After intensified control measures, the number of students screened positive for CA-MRSA decreased from nine to one with no more cases identified in the school.Conclusion：Identification of carriers, decolonization therapy, monitoring of cases and contacts and strengthening of environmental and personal hygiene were control measures that helped contain this CA-MRSA outbreak in a boarding school in Hong Kong Special Administrative Region (China).

Objective To monitor the levels of radioactive contamination due to the Japanese Fukushima nuclear accident in Beijing,so as to provide scientific technical information for government to draw effective controlling strategy and processing mechanism.Methods The system of nuclear emergency nmonitoring was started,then the radioactive contamination levels of atmosphere,rain water,surface water and vegetables in Beijing were detected according to the relative survey regulations and technology criterions.Results During the period from 15 to 41 d after the accident,obvious radioactive contamination was found in the atmosphere of Beijing.The maximum radioactivity concentration of 131I ( 5.89 mBq/m3 ) was detected at 22 d after the accident.The radioactivity concentrations of 137Cs and 134Cs were surveyed forming their corresponding peaks at 20 d after the accident,but they were one magnitude lower than the peak value of 131I at least.In addition,the gross β radioactivity level in the water of Chao Bai-he river was verified to be in the range of 0.314 - 0.602 Bq/L. Conclusions The radioactive contamination due to Fukushima nuclear accident has not done visible harm to the public health in Beijing,but monitoring should be continued to observe the long-term effect of the accident.

Abstract: Objective　To analyze the influencing factors of mother-to-child transmission of hepatitis B virus after combined immunological blockade, and to evaluate the effect of mother-to-child blockade, and to provide a basis for health policies and health interventions for preventing mother-to-child blockade of hepatitis B virus. Methods A total of 11 363 pairs of HBsAg positive pregnant women and their infants aged 7-12 months in Hainan Province from 2015 to 2020 were included in the study. The general situation, the situation of health care and delivery in this pregnancy and perinatal period, the detection of hepatitis B markers, the situation of antiviral therapy, the general situation of mother and infant during delivery and the implementation of blockade measures for mother-to-child transmission of hepatitis B were collected and analyzed. Results Among the 11 363 pairs of HBsAg positive pregnant women and their infants delivered in hospitals in Hainan province from 2015 to 2020, the positive rate of HBsAg in children at 7-12 months after birth was 1.47 %, and the difference in HBsAg positive rate of infants born in different years was not statistically significant (P>0.05). There were no significant differences in the positive rate of HBsAg among children born to pregnant women with different nationalities, educational levels, occupations, delivery modes, delivery places, obstetric operations and perineal laceration, abnormal perinatal period, children with different genders and premature delivery and perinatal (all P<0.05). There was significant difference in HBsAg positive rate among infants born to pregnant women of different ages, the positive rate of HBsAg of infants born to young pregnant women was higher than that of older pregnant women (P<0.05). The rate of antiviral therapy was low in HBeAg positive pregnant women, and the positive rate of HBsAg in their infants was 2.54%, which was higher than 0.83% in HBeAg negative pregnant women (P<0.05). Conclusions Combined immunological blockade with hepatitis B vaccine and hepatitis B immunoglobulin can effectively prevent the mother-to-child transmission of HBV. HBsAg-positive women can give birth at the right age, and HBeAg-positive pregnant women can be treated with antiviral therapy to block mother-to-child transmission, providing the important basis for the formulation of hepatitis B prevention and control strategies and measures.

Blood Coagulation Disorders ; drug therapy ; Child ; Child, Preschool ; Drug Therapy, Combination ; Female ; Heparin ; administration & dosage ; Humans ; Male ; Nephrotic Syndrome ; blood ; complications ; urine ; Urokinase-Type Plasminogen Activator ; administration & dosage

OBJECTIVETo analyze the change in nitration tyrosine, NO(2)(-)/NO(3)(-)level in induced sputum of silicosis patients and dust exposure workers and to evaluate the approach and feasibility of nitric oxide (NO) metabolites as early detection indicators of silicosis.

METHODSNitration tyrosine, NO(2)(-)/NO(3)(-)concentration in induced sputum of 80 dust exposure workers, 84 silicosis patients, 30 logistic personnel with no history of exposure to silica dust were determined and the relationship among Nitration tyrosine, NO(2)(-)/NO(3)(-)level and dust exposure years as well as pulmonary function tests were analyzed.

RESULTSNO(2)(-)/NO(3)(-)level among exposed group [60.30 (46.58) micromol/l] was significantly higher than the control group [36.90 (22.28) micromol/l], (P < 0.05), and the level of NO(2)(-)/NO(3)(-)among the cases [79.65 (89.10) micromol/l] was significantly higher than exposed group as well as the control group (P < 0.05). Compared with control, the level of nitration tyrosine in exposed group [3.51 (0.46) nmol/l] and the cases [3.48 (0.49) nmol/l] was significantly higher (P < 0.05). NO(2)(-)/NO(3)(-)level and dust exposure years were positively correlated (r = 0.3733 and 0.3830 respectively P < 0.05); NO(2)(-)/NO(3)(-)level and pulmonary function tests (FVC%, FEV1.0%, PEF%, MEF25%, MEF50%) were negatively correlated (r = 0.1540, 0.1723, 0.1535, 0.1485, 0.1643 respectively, P < 0.05). There was no correlation between nitration tyrosine and dust exposure years (P > 0.05), no correlation between nitration tyrosine and pulmonary function test (P > 0.05).

CONCLUSIONThe level of NO(2)(-)/NO(3)(-)level in induced sputum has a positive correlation with exposure to dust, suggesting that there will be a certain feasibility of the NO(2)(-)/NO(3)(-)as indicators of early detection of silicosis.

Adult ; Humans ; Middle Aged ; Nitrates ; metabolism ; Nitrites ; metabolism ; Silicosis ; metabolism ; Sputum ; metabolism ; Tyrosine ; metabolism

BACKGROUND:The roles of osteocyte and osteoblast apoptosis in steroid-induced avascular necrosis of the femoral head (ANFH) have arouse much attention,and its pathogenesis has been understood gradually.But there is a lack of knowledge about the mechanisms underlying osteocyte and osteoblast apoptosis.Meanwhile,hormones have been shown to enhance the Dickkopf-1 expression in Wnt signaling pathway.OBJECTIVE:To investigate the roles of Dickkopf-1 and cell apoptosis in steroid-induced ANFH,and to understand their correlations with steroid-induced ANFH.METHODS:Necrotic femoral head samples were removed from 14 patients with steroid-induced ANFH after total hip arthroplasty (experimental group),and normal femoral heads were from 8 patients with femoral neck fracture (control group).The cellular morphology was observed using transmission electron microscope;the number of empty lacunae was counted through hematoxylin-eosin staining;the cell apoptosis was detected by TUNEL assay;the expression level of Dickkopf-1 was detected by immunohistochemistry.Moreover,the correlation between the Dickkopf-1 positive rate and apoptosis index of osteocytes was analyzed by Spearman rank correlation analysis.RESULTS AND CONCLUSION:The number of empty lacunae,expression level of Dickkopf-1,and apoptosis index of osteocytes in the experimental group were significantly higher than those in the control group (P ＜ 0.05).In the experimental group,the Dickkopf-1 positive rate was positively correlated to the apoptosis index of osteocytes (r=0.623).These results indicate that Dickkopf-1 and osteocyte apoptosis both play key roles in steroid-induced ANFH,and increased Dickkopf-1 level may promote the development of ANFH.

Hyperphenylalaninemia is one of the commonest inborn errors of metabolism affecting approximately 1 in 15,000 livebirths. Among Chinese, BH4 deficiency leading to hyperphenylalaninemia is much commoner than in Caucasians. Exact diagnosis is important for the treatment and genetic counseling. In 2000, newborn screening for phenylketonuria is mandatory by law in China throughout the whole country. However, it is not yet included in the newborn screening program of the Hong Kong Special Administrative Region, China. Published data on hyperphenylalaninemia among HongKong Chinese are largely lacking. We report a 1-year-old Hong Kong Chinese girl with severe 6-pyruvoyl-tetrahydropterin synthase (PTPS) deficiency. The patient presented with infantile hypotonia and was misdiagnosed as cerebral palsy. She had very mild hyperphenylalaninemia (95 μmol/L), significantly high phenylalnine-to-tyrosine ratio (3.1), and elevated prolactin of 1109 mIU/L. Genetic analysis confirmed a homozygous known disease-causing mutation PTS NM_000317.1:c.259C>T; NP_000308.1: p.P87S in the proband. In our local experience, while the estimated prevalence of hyperphenylalaninemia due to PTPS deficiency was reported to be 1 in 29,542 live births, not a single case of phenylalanine hydroxylase deficiency has been reported. Furthermore, there is a general lack of awareness of inherited metabolic diseases in the community as well as among the medical professionals. Very often, a low index of clinical suspicion will lead to delay in diagnosis, multiple unnecessary and costly investigations, prolonged morbidity and anxiety to the family affected. We strongly recommend that expanded newborn screening for hyperphenylalaninemia should be implemented for every baby born in the Hong Kong Special Administrative Region, China.
Asian Continental Ancestry Group ; China ; Female ; Hong Kong ; Humans ; Infant ; Mass Screening ; Phenylketonurias ; diagnosis

Background: The occurrence of Graves’ disease and Hashimoto thyroiditis after coronavirus disease 2019 (COVID-19) raised concerns that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) may trigger thyroid autoimmunity. We aimed to address the current uncertainties regarding incident thyroid dysfunction and autoimmunity among COVID-19 survivors. Methods: We included consecutive adult COVID-19 patients without known thyroid disorders, who were admitted to Queen Mary Hospital from July 21 to September 21, 2020 and had serum levels of thyroid-stimulating hormone, free thyroxine, free triiodothyronine (fT3), and anti-thyroid antibodies measured both on admission and at 3 months. Results: In total, 122 patients were included. Among 20 patients with abnormal thyroid function tests (TFTs) on admission (mostly low fT3), 15 recovered. Among 102 patients with initial normal TFTs, two had new-onset abnormalities that could represent different phases of thyroiditis. Among 104 patients whose anti-thyroid antibody titers were reassessed, we observed increases in anti-thyroid peroxidase (TPO) (P<0.001) and anti-thyroglobulin (P<0.001), but not anti-thyroid stimulating hormone receptor titers (P=0.486). Of 82 patients with negative anti-TPO findings at baseline, 16 had a significant interval increase in anti-TPO titer by >12 U, and four became anti-TPO-positive. Worse baseline clinical severity (P=0.018), elevated C-reactive protein during hospitalization (P=0.033), and higher baseline anti-TPO titer (P=0.005) were associated with a significant increase in anti-TPO titer. Conclusion Most patients with thyroid dysfunction on admission recovered during convalescence. Abnormal TFTs suggestive of thyroiditis occurred during convalescence, but infrequently. Importantly, our novel observation of an increase in anti-thyroid antibody titers post-COVID-19 warrants further follow-up for incident thyroid dysfunction among COVID-19 survivors.

Background: The occurrence of Graves’ disease and Hashimoto thyroiditis after coronavirus disease 2019 (COVID-19) raised concerns that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) may trigger thyroid autoimmunity. We aimed to address the current uncertainties regarding incident thyroid dysfunction and autoimmunity among COVID-19 survivors. Methods: We included consecutive adult COVID-19 patients without known thyroid disorders, who were admitted to Queen Mary Hospital from July 21 to September 21, 2020 and had serum levels of thyroid-stimulating hormone, free thyroxine, free triiodothyronine (fT3), and anti-thyroid antibodies measured both on admission and at 3 months. Results: In total, 122 patients were included. Among 20 patients with abnormal thyroid function tests (TFTs) on admission (mostly low fT3), 15 recovered. Among 102 patients with initial normal TFTs, two had new-onset abnormalities that could represent different phases of thyroiditis. Among 104 patients whose anti-thyroid antibody titers were reassessed, we observed increases in anti-thyroid peroxidase (TPO) (P<0.001) and anti-thyroglobulin (P<0.001), but not anti-thyroid stimulating hormone receptor titers (P=0.486). Of 82 patients with negative anti-TPO findings at baseline, 16 had a significant interval increase in anti-TPO titer by >12 U, and four became anti-TPO-positive. Worse baseline clinical severity (P=0.018), elevated C-reactive protein during hospitalization (P=0.033), and higher baseline anti-TPO titer (P=0.005) were associated with a significant increase in anti-TPO titer. Conclusion Most patients with thyroid dysfunction on admission recovered during convalescence. Abnormal TFTs suggestive of thyroiditis occurred during convalescence, but infrequently. Importantly, our novel observation of an increase in anti-thyroid antibody titers post-COVID-19 warrants further follow-up for incident thyroid dysfunction among COVID-19 survivors.