ABSTRACT
Objective:To analyze the incidence, biochemical and molecular characteristics, and gene mutation spectrum of neonatal methylmalonic acidemia (MMA) in Shaanxi province.Methods:This study involved 146 152 newborns undergoing neonatal screening for methylmalonic acidemia by tandem mass spectrometry in Northwest Women's and Children's Hospital from January 2014 and December 2019. Clinical manifestations and follow-up data of newborns diagnosed with MMA and their acylcarnitine profiles and gene mutations were analyzed. According to whether they had elevated homocysteine or not, these patients were divided into two groups, the complicated group and the isolated MMA group. The control neonates were those excluded from having methylmalonic acid by re-examination. Kruskal-Wallis and Mann-Whitney U test was conducted for statistical analysis. Results:(1) Twenty-one cases of MMA were confirmed with an incidence of 1/6 960, including 11 cases (52.4%) of isolated MMA (isolated MMA group) and 10 (47.6%) complicated by elevated homocysteine (complicated group). Eight patients in the isolated group had symptoms within one month after birth, mainly feeding difficulties, vomiting, drowsiness, poor response and infection, and five died. Patients in the complicated group were all diagnosed before developing typical clinical symptoms, and no developmental abnormalities were reported during follow-up. (2) Blood propionyl carnitine and its ratios to acetylcarnitine and free carnitine in the isolated MMA and complicated groups were higher than those in the control group [ M (min-max), 9.26 (3.70-37.78) μmol/L and 7.27 μmol/L (3.58-13.62 μmol/L) vs 4.51 μmol/L (1.48-8.69 μmol/L), H=23.239; 1.12 (0.32-2.43) and 0.74 (0.36-1.90) vs 0.25 (0.09-0.45), H=47.061; 0.94 (0.12-1.92) and 0.56 (0.18-1.03) vs 0.17 (0.06-0.38), H=36.868; all P<0.001]. The blood methionine level in the complicated group was significantly lower than that in the isolated MMA group [7.64 μmol/L (3.40-19.25 μmol/L) vs 24.22 μmol/L (10.73-56.55 μmol/L), U=3.000, P<0.001]. (3) All 21 patients carried complex heterozygous mutations or homozygous mutations in pathogenic genes, including 15 distinct MMUT mutations and 13 distinct MMACHC mutations. In the isolated MMA group, the most common mutation was c.323G>A (p.Arg108His) in the MMUT gene with a positive rate of 13.6%, and an unreported mutation, c.1676+11A>G, with unidentified clinical significance, was also found. The most common mutations in the complicated group were c.609G>A (p.Trp203Ter) and c.567dupT (p.Ile190fs) in the MMACHC gene, and the positive rates were both 20.0%. Moreover, two unreported variants, c.430-2A>C and c.648_650delAGA (p.216_217delSEinsS), were detected and suspected to be pathogenic. Conclusions:MMA is not uncommon in Shaanxi province. Children with isolated MMA tend to be more severe clinically. The identification of hotspot mutations, including c.609G>A (p.Trp203Ter) and c.567dupT (p.Ile190fs) in MMACHC gene and c.323G>A (p.Arg108His) in MMUT gene, provides a foundation for further genetic screening, counseling, and prenatal diagnosis, and is conducive to reduce the mortality and disability rate of neonatal MMA.
ABSTRACT
Objective To develop a portable endoscopic thermal device which possesses the merits of compact structure,convenient operation,security and good compatibility.Methods Rapid heating elements and several materials are used,which are excellent insulation,heat conduction and can withstand high temperatures.The production process of miniaturization,anti-conglutination and constant temperatureare adopted.Results: The size of Heat probe is about 2.4mm in outer diameter and 8 mm in length.The maximum temperature will reach 250℃,heating time within 10s,output 4.5～6.5W.Conclusion Heat Probe can be compatible with various types gastrointestinal endoscopic channel.Besides hemostasis of upper gastrointestinal,it can also be applied to small polyps,erosive gastritis,etc.
ABSTRACT
Objective: To study the influence of electret on surface charge of fibroblast cells (3T3 cells) and to probe the relationship between cell growth, apoptosis and cell surface charge. Methods: Electrets Teflon PTFE, ±300 V,±1 000 V were used to treat 3T3 cells for 24, 48 and 72 h. Then the influences of electrets on cell cycle and surface charge of 3T3 cells were studied by flow cytometry and electrophoresis, respectively. Results: (1) After 24 h action of negative electrets, electrophoretic mobility (or surface charge) and cell number in S phase of 3T3 cells were significantly increased compared with those in control group. (2) Effect of negative electrets enhancing cell growth and increasing cell surface charge was in proportional to the surface potential of electret. (3) Surface charge density of apoptotic cell was reduced by electret. (4) After 24 h action of positive electret, the cell number in S and G2 phase were decreased and cell surface charge was also reduced. Conclusion: Negative electret can improve cell growth and increase cell surface charge density. Positive electret can restrain cell growth and reduce cell surface charge density. Surface charge of apoptotic cell is less than that of normal cell.
ABSTRACT
Objective: To study the influence of negative electrets on apoptosis of fibroblast cells and to probe its mechanism. Methods: Fibroblast cell were treated with -300, -500 and -1 000V PTFE electrets for 24, 48 and 72 h, respectively, and the influence of negative electrets on cell apoptosis was studied by means of flow cytometry and transmission electron microscope. Results: Compared with control group, apoptosis cells increased from 0.5% to 10% (some even to 15%) after 24，48 and 72 h action of -300, -500 and -1 000 V electrets. After action of -500 V PTFE electrets for 48-72 h, fibroblast cells showed characteristic morphological features of apoptosis. These features included chromatin aggregation, nuclear and cytoplasmic condensation and partition of cytoplasm and nucleus into membrane bound-vesicles (apoptotic bodies). The effect of negative electrets on apoptosis was in proportion to the time and electric field intensity. Conclusion: Negative electrets can enhance apoptosis of fibroblast cells.
ABSTRACT
Objective:To investigate the protective effect of adenosine on cochlea in acute acoustic trauma. Methods: Guinea pigs were exposed to 118 dB SPL white noise for 30 min. During the process of exposure, artificial perilymph or artificial perilymph containing adenosine (0.1 mmol/L,1 mmol/L or 5 mmol/L) was infused into the cochlea through perilymphatic perfusion. Concentration of glutamate in perilymph and thresholds of compound action potentials (CAP) were measured before and after noise exposure. Results: After exposure, the concentration of glutamate and the mean threshold shifts evoked by click were significantly higher than those of before exposure. Concentration of glutamate and thresholds of CAP in adenosine (1 mmol/L and 5 mmol/L) treated groups were significantly lower than those of the control group. Conclusion: Adenosine can inhibit the elevation of glutamate and decrease the threshold shift of CAP after exposure to noise,which can protect cochlea in acute acoustic trauma in guinea pigs.