Medium-term results of ceramic-on-polyethylene Zweymüller-Plus total hip arthroplasty.

INTRODUCTION: The need for better durability and longevity in total hip arthroplasty for patients with various hip joint diseases remains a challenge. This study aimed to obtain medium-term results at a follow-up of >10 years for Zweymüller-Plus total hip arthroplasty with ceramic-on-polyethylene bearing. METHODS: A retrospective study was conducted to review the results after a minimum of 12.4 years of 207 consecutive total hip arthroplasties in 185 patients in Peking University People's Hospital in China using the Zweymüller SL-Plus stem in combination with the Bicon-Plus threaded cup and ceramic-on-polyethylene bearing between October 1994 and April 2000. RESULTS: During the study period, two patients (2 hips) died and 25 patients (28 hips) were lost to follow-up. Two hips were revised for aseptic loosening of the Bicon-Plus cup. The mean clinical and radiological follow-up was 14.1 years (range, 12.4-16.5 years) for the remaining 156 patients (175 hips). The mean (standard deviation) Harris Hip score for the 175 hips increased significantly from 39.3 (3.8) preoperatively to 94.1 (2.5) postoperatively at a mean follow-up of 14.1 years (P<0.05). Focal osteolysis was observed in seven (4.0%) of 175 stems and three (1.7%) of 175 cups. The Kaplan-Meier survival with revision for any reason as the end-point was 99.03% (95% confidence interval, 95%-100%). CONCLUSIONS: The high survival rate of the cementless Zweymüller-Plus system with ceramic-on-polyethylene bearing at mid-term follow-up makes this total hip arthroplasty system reliable for patients with various hip joint diseases.

[A cohort study on occupational noise induced hearing loss in workers at an iron and steel plant].

Objective: To analyze the incidence rate of occupational noise-induced hearing loss in noise-exposed workers in an iron and steel plant from 2006 to 2015. Methods: Using a cohort study method, workers exposed to occupational noise from Jan 1, 2006 to Dec 12, 2015 were followed up and the pure tone hearing test was conducted. In total, 6 297 subjects completed two or more physical checks and the pure tone hearing test and were included in the analysis. The noise exposure level at the workplace and the equivalent continuous A-weighted sound pressure level for workers was monitored and the cumulative noise exposure dose was evaluated. The subjects were divided into low, middle and high exposure groups according to the noise exposure level, and the equivalent continuous A-weighted sound pressure level for 8 hours for each group was 80.6-85.0, 85.1-90.0 and 90.1-103.4 dB (A), respectively. While the RR and 95% CI were derived from unconditional logistic regression models. In logistic regression analysis, confounding factors such as age, gender, smoking habit, drinking habit, high temperature exposure and chemical hazards exposure level were controlled. Results: During the follow-up period, 392 cases of occupational noise-induced hearing loss were diagnosed among the 6 297 subjects, with an incidence rate of 6.23%; 318 cases of high-frequency hearing loss were diagnosed, with an incidence rate of 5.05%; and 74 cases of occupational noise-induced deafness were diagnosed, with an incidence rate of 1.18% . The incidence rates of hearing loss among the high, medium and low exposure groups were 9.22% (158/1 737), 6.49% (204/3 142) and 2.08% (30/1 442), respectively; the rates of high-frequency hearing loss were 7.41% (127/1 737), 5.25% (165/3 142) and 1.80% (26/1 442), respectively; and the rates of occupational noise-induced deafness were 1.81% (31/1 737), 1.24% (39/3 142) and 0.28% (4/1 442), respectively. For the groups corresponding to cumulative noise exposure doses of ≤84.99, 85.00- 87.99, 88.00- 90.99, 91.00- 93.99, 94.00- 96.99, 97.00- 100.99, 101.00- 102.99 and ≥103.00 dB (A) · year, the incidence rates of hearing loss were 0 (0/185), 1.22% (2/164), 2.52% (17/674), 3.83% (35/913), 5.80% (106/1 827), 6.02% (67/1 113), 9.20% (95/1 003) and 18.04% (70/388), respectively. Compared with the low exposure group, the RR of hearing loss, high-frequency hearing loss and occupational noise-induced deafness for the high exposure group were 4.78 (95% CI: 3.22- 7.11), 4.36 (95% CI: 2.84- 6.69) and 6.63 (95% CI: 2.33- 18.82), respectively; and for the medium exposure group were 3.27 (95% CI: 2.22-4.82), 3.02 (95% CI: 1.99-4.59) and 4.52 (95% CI: 1.61-12.67), respectively. Conclusion: The incidence rate of hearing loss for workers exposed to noise in an iron and steel plant was related to the cumulative noise exposure dose, gender, age, educational level, smoking habits, drinking habits and exposure to high temperature.

Review Recent progress in identification and characterization of loci associated with sex-linked congenital cataract.

Congenital cataract is a common cause of blindness in children; however, its pathogenesis remains unclear. Genetic factors have been shown to play an important role in the pathogenesis of congenital cataract. The current genetic models of congenital cataract include autosomal dominant, autosomal recessive, and sex-linked inheritance. Sex-linked congenital cataract could be inherited through the X or Y chromosome. Congenital cataract is a symptom associated with several X-linked disorders, including Nance-Horan syndrome, Lowe syndrome, Conradi-Hünermann-Happle syndrome, oculo-facio-cardio-dental syndrome, and Alport syndrome. On the other hand, the mechanism and characteristics of Y-linked congenital cataract remains to be identified. Despite its rarity, sex-linked congenital cataract has been known to seriously affect the quality of life of patients. In this review, we present our current understanding of the genes and loci associated with sex-linked congenital cataract. This could help identify novel approaches for the prevention, early diagnosis, and comprehensive disease treatment.

A membrane bioreactor for an innovative biological nitrogen removal process.

A hybrid system has been developed for biological nitrogen removal through nitrification-denitrification. The system includes an aerobic tank and an anoxic tank with an intermediate sludge settler connected to a membrane bioreactor (MBR) with a submerged 0.4 microm hollow-fiber membrane module. The laboratory system has a total working volume of 6.5 L treating a glucose-based synthetic wastewater. The experimental results demonstrate that the new process is highly effective for simultaneous organic and nitrogen removal. During the stationary operation, a sludge SS (suspended solids) concentration of 6 g/L or higher can be maintained in the reactors. The system has a COD (chemical oxygen demand) loading rate of up to 2,100 mg/L-d and a total nitrogen loading rate of up to 170 mg N/L-d. More than 95% COD can be degraded, and the total nitrogen removal efficiency can be 90% or higher as the nitrogen is reduced from 100 to around 7.5 mg/L. A high quality effluent is produced with a SS of less than 1 mg/L. With the MBR, organic degradation, nitrogen removal and sludge-liquid separation can be well achieved within a short HRT of about 10 hr.

[Establishment of a dexamethasone-induced congenital cleft palate model in New Zealand rabbits].

Objective: To develop a new congenital cleft palate model suitable for the evaluation of cleft palate surgery and other related treatments. Methods: Ten New Zealand female rabbits (aged 40 weeks, 4.5-5.0 kg) were selected. The next day after mating with male rabbits of the same strain was regarded as the day 1 of gestation (GD1). Ten pregnant rabbits were enrolled with intramuscular injection 1.0 mg dosage of dexamethasone once a day from GD13 to GD16. The caesarean section was performed to obtain the newborn rabbits on GD31 for each pregnant rabbit. Then the rates of the survival and cleft palate rabbits were calculated. The rabbits were divided into two groups according to the method of random number table (10 non-cleft palate rabbits as the control group and 10 cleft palate rabbits as the experimental group). The body weights and physiological behaviors of the rabbits were evaluated and recorded at the age of 1, 2 and 4 weeks respectively after being fed by using standardized gastric tube feeding method. At 4 weeks old, three rabbits in each group were randomly selected for the observation of local anatomy of different layers of the mouth and upper jaw. The anatomical results were photographed for comparative analysis. Results: In this experiment, 48 infants of 10 pregnant rabbits survived under the condition with a survival rate of 66% (48/73), among which the incidence of cleft palate was 60% (29/48). All the rabbits in the control group and the experimental group were able to survive for at least 1 month with stable weight gain. There was no significant difference in weight (P>0.05) and physiological appearance between the two groups. In cleft palate group, most of fetuses showed complete cleft palate with significant differences in the anatomical structure of the upper jaw compared with the control group including the changes in the morphology of the palatal mucosa, the terminal distribution of the soft palate muscles, and the dysplasia and absence of bone structures along the mid-maxillary line. Conclusions: In this study, it was the first time to successfully establish the dexamethasone-induced congenital cleft palate model in New Zealand rabbits for cleft surgical research.

[Analysis of the discrepancy of crown-root morphology of central incisors among different skeletal malocclusion using cone-beam CT].

Objective: To investigate the discrepancy of crown-root morphology of upper and lower central incisors in adult patients with different skeletal malocclusions using cone-beam CT (CBCT). Methods: Patients visiting the Department of Orthodontics, College of Stomatology, Xi'an Jiaotong University from January 2015 to December 2017 were selected, including 108 cases (52 males, 56 females, aged from 18 to 30 years, mean age 25.8 years). According to CBCT data and cephalometric analysis, 66 patients with average angle were selected as the sagittal skeletal group, including 24 Class Ⅰ patients, 20 Class Ⅱ and 22 Class Ⅲ patients. In the other selected 66 skeletal Class Ⅰ patients including 21 low angle patients, 24 average angle patients (from the sagittal skeletal Class Ⅰ subgroup) and 21 high angle patients. Invivo 5 software was used to locate the CBCT image three dimensionally and then obtain the middle labio-lingual section of right central incisor. Auto CAD 2007 software was applied to measure the angle formed by the long axis of root and the extension line of the long axis of crown (Collum angle), and the angle between the long axis of crown and the lip tangent line passing through the center of the labial surface of crown (labial surface angle). One-way ANOVA and Scheff were used to analyze the discrepancies among classifications and Pearson correlation analysis was used to determine the correlation between the Collum angles and labial surface angles. Results: Significant differences were found in Collum angles and labial surface angles among different sagittal skeletal patterns (P<0.05). The Collum angle of maxillary central incisors in Class Ⅱ patients was 5.18°±4.97° and the average labial surface angle was 17.78°±3.74°, which were both significantly higher than that of maxillary central incisors in Class Ⅰ and Ⅲ subgroups (P<0.05). Similarly, the above two angles of mandibular central incisors in Class Ⅲ were 5.59°±5.64° and 15.32°±3.05°, which were significantly higher than that of mandibular central incisors in Class Ⅰ and Ⅱ subgroups (P<0.05). There was no significant difference among different vertical skeletal patterns (P>0.05). Notably, the Collum angles of maxillary or mandibular central incisors presented significantly positive correlation with labial surface angles (maxillary: r=0.723, P<0.001; mandibular: r=0.752, P<0.001). Conclusions: The long axis of the crown of the maxillary central incisor in skeletal Class Ⅱ patients and the mandibular central incisor in skeletal Class Ⅲ patients are obviously deviated toward the lingual side relative to the long axis of the root, and correspondingly there is a greater labial surface angle of the crown, which indicates that equivalent positioning deviation during bracket bonding can cause greater torque expression error.

[The surgical management of upper parapharyngeal regions].

Objective: To find proper the surgical approval and evaluate clinical efficacy to treat the tumor of upper parapharyngeal space involving the base of skull and intracranial skull. Method: The data of 9 cases from June 2013 and June 2018 were analyzed retrospectively including schwannoma in 6 cases, pleomorphic adenoma in 2 cases and hemangioma in 1 case. All cases received preoperative high resolution CT and MRI, some cases also did the DSA examination. Tumor invaded top of nasopharyngeal in 4 cases, the base of skull in 3 cases, and intraskull in 2 cases. 9 cases were treated with surgery alone. Surgical approach: transcervical approach (n=1), transcervical approach and mandibular fracture surgery(n=2), transoral approach(n=3), transnasal transpterygoid approach(n=2), transparotid gland approach(n=1). Result: Tumors in 8 cases were completely removed, and 1 case was performed by partial excision. Hemorrhage(>500 ml) occurred in 2 cases, tongue deflection and cerebrospinal fluid leakage occurred in 1 case. No death, tumor recurrence and wound infection was found. Conclusion: The position of benign upper parapharyngeal space tumors is deep and tumor often invade in the base of the skull and brain tissue. It is close to the important nerve, vessels of the skull base and meninges. The appropriate surgical approach should be selected according to the individual situation. The main point of the operation is complete the tumor resection with preserving or reconstructing the important function of the blood vessel and nerve.

[Effects of Porphyromonas endodontalis lipopolysaccharides on the expression of matrix metalloproteinase-9 in mouse osteoblasts].

Objective: To evaluate the effects of lipopolysaccharides (LPS) extracted from Porphyromonas endodontalis (Pe) on the expression of matrix metalloproteinase-9 (MMP-9) mRNA and protein as well as enzyme activity in MC3T3-E1 cells and the role of nuclear factor-κB (NF-κB) in the process, so as to investigate the expression of MMP-9 dependent signaling pathways in mouse osteoblasts induced by Pe LPS. Methods: The experiment was conducted in 3 sessions: MC3T3-E1 cells were treated with various concentrations of Pe LPS (0-20 mg/L) and 10 mg/L Pe LPS for different time intervals (0-48 h). The expression of MMP-9 mRNA and protein were detected by real-time reverse transcription-PCR (RT-PCR) and enzyme-linked immunosorbent assay (ELISA), while the enzyme activity was detected by gelatin zymography method. The expression of MMP-9 mRNA was also detected in 10 mg/L Pe LPS treated MC3T3-El cells after pretreated with specific NF-κB inhibitor BAY 11-7082 for l h. Statistical analysis was performed using one-way ANOVA and Dunnett t test with SPSS 13.0 software package. Results: The levels of MMP-9 mRNA and protein increased significantly after the treatment with various concentrations of Pe LPS (0-20 mg/L), which indicated that Pe LPS induced osteoblasts to express MMP-9 in dose dependent manners. The expression of MMP-9 protein increased from (5 395±362) ng/L (blank control group) to (12 684±375) ng/L (20 mg/L group). Maximal induction of MMP-9 mRNA expression was found in the MC3T3-E1 cells treated with 10 mg/L Pe LPS for 24 h. The expression of MMP-9 mRNA in the 20 mg/L group was about 7 times than that in the blank control group. After 24 h, the expression of MMP-9 mRNA decreased. Maximal expression of MMP-9 protein was found in the MC3T3-E1 cells treated with 10 mg/L Pe LPS for 48 h ([35 055±2 346] ng/L) showing the highest enzyme activity. The mRNA of MMP-9 decreased significantly after pretreatment with 10 µmol/L BAY 11-7082 for 1 h. Conclusions: Pe LPS might induce the expression of MMP-9 in MC3T3-E1 cells through the signaling of NF-κB.

Property variations in the prism and the organic sheath within enamel by nanoindentation.

Atomic force microscopy (AFM) combined with nanoindentation technique was used to definitely, site-specifically, test the nanomechanical properties, including nanohardness and elastic modulus, of the isolated domains within single enamel, the prisms and the surrounding sheaths, of mature human maxillary third molars. In this way, it is for the first time that evident differences of nanomechanical properties were revealed between these domains. The nanohardness and elastic modulus of the sheaths were about 73.6% and 52.7% lower than those of the prisms, respectively. Measuring the residual impressions with AFM supported the similar conclusion. The variations of mechanical properties in these domains are considered to be mainly relative to their different component and fibrils arrangement.

Uptake of liposomes by cultured cardiomyocytes.

Small unilamellar liposomes (SUV) of different phospholipid/polymer composition were labeled with NBD-PC, which served as a bilayersituated fluorescence marker. Neonatal cardiomyocytes were incubated with liposomes and then the cell-associated fluorescence was measured. The factors influencing the liposome uptake by cardiomyocytes such as concentration of lipid, time of incubation, membrane fluidity of liposomes, charge lipid/polymer modification of liposomes and anoxia of cultured cardiomyocytes were investigated. The liposome uptake by cardiomyocytes increased dose-dependently and time-dependently. Liposome uptake was strongly influenced by the electrical charge and modified polymer. After 2 h incubation, the uptake of positively charged liposomes was 1.7-fold higher than that of negatively charged one and both higher than that of the neutral one. The presence of PE-PEG2000 distinctly reduced the liposome uptake and the difference between the uptake of charged and neutral liposome. Anoxia increased the uptake of liposome at the first hour (increased 20%), but after 2 h incubation the liposome uptake by hypoxia cellswas less than that of normoxia cells (decreased 18%). Mechanisms involved are also discussed.

Oral Helicobacter pylori, its relationship to successful eradication of gastric H. pylori and saliva culture confirmation.

The present study was designed to explore the existence of oral Helicobacter pylori (H. pylori), its relationship in the oral cavity to the success rate of eradication of the gastric H. pylori infection, and to determine if the mouthwash solution contained lysine (0.4%) and glycerol monolaurate (0.2%) (LGM) could eliminate oral H. pylori, as well as using the saliva H. pylori culture to confirm the existence of oral H. pylori. A total of 159 symptomatic individuals with stomach pain and 118 asymptomatic individuals with no stomach complaints, were recruited and tested using the saliva H. pylori antigen test (HPS), the H. pylori flagellin test (HPF), the urea breath test (UBT C(13)) and the polymerase chain reaction (PCR) test, which tests were also confirmed by saliva culture. The test subjects also received various treatments. It was found that the H. pylori antigen exists in the oral cavity in UBT C(13) negative individuals. Traditional treatment for gastric eradication had only a 10.67 percent (10.67%) effectiveness rate on the oral H. pylori infection. In groups of patients with the oral H. pylori infection, but with negative UBT C(13), a mouthwash solution provided a 72.58% effectiveness rate in the 95% of the confidence interval (CI) ranges on the oral H. pylori infection. Traditional drug gastric eradication and teeth cleaning (TC) had less than a 10% effectiveness rate. Treatment of the oral infection increased the success rate of eradication of the stomach infection from 61.33% to 82.26% in the 95% CI ranges. We concluded that the successful rate of eradication of gastric H. pylori bears a significant relationship to the oral infection from H. pylori.

Asymmetric muscle function in patients with developmental mandibular asymmetry.

The aim was to test the hypothesis that developmental mandibular asymmetry is associated with increased asymmetry in muscle activity. Patients with mandibular condylar and/or ramus hyperplasia having unilateral cross-bite were compared with healthy subjects with normal occlusion. Muscle activity was recorded with surface electrodes in the masseter, suprahyoid, sternocleidomastoid muscle (SCM) and upper trapezius areas during jaw opening-closing-clenching, head-neck flexion-extension, and elevation-lowering of shoulders. Root mean square (RMS) and mean power frequency (MPF) values were calculated and analysed using anova and t-tests with P < 0.05 chosen as significance level. The SCM and masseter muscles showed co-activation during jaw and head movements, significantly more asymmetric in the patients than in the healthy subjects. The RMS and MPF values were higher in the patients than in the controls in the SCM and suprahyoid areas on both sides during jaw opening-closing movement. The results indicate that the ability to perform symmetric jaw and neck muscle activities is disturbed in patients with developmental mandibular asymmetry. This is of clinical interest because asymmetric activity may be an etiologic factor in temporomandibular joint and cervical pain. The results support that co-activation occurs between jaw and neck muscles during voluntary jaw opening and indicate that postural antigravity reflex activity occurs in the masseter area during head extension. Further studies, where EMG recordings are made from the DMA patients at early stages are motivated to verify activity sources and test if the asymmetric activity is associated with muscle and joint pain in the jaw and cervical areas.

Demonstration of identical strains of mutans streptococci within Chinese families by genotyping.

The aim of this study was to investigate the intra-familial distribution of mutans streptococci in some Chinese families. Eighteen families consisting of mother, father and a 3-yr-old child without any older siblings participated. Clinical examination and interview were performed to obtain information about level of mutans streptococci in saliva, caries prevalence scored by DMFT or deft, general health, diet regimens, breast-feeding time, principal caretaker of the child and the parents' profession. At the same appointment, two pooled plaque samples from each subject were collected with the tips of sterile tooth picks. From these plaque samples, mutans streptococci were isolated on MSB-agar plates and identified by serotyping. Pure isolates were obtained from all subjects of 11 families. These isolates were genotyped using restriction endonuclease HaeIII. The results showed that in 4 families the mothers shared genotype with the child, and in 3 families it was the father and the child who harboured a similar genotype. In 2 families, all subjects harboured an identical genotype. Further, the spouses in one parental pair showed an identical genotype, and, finally, in one family all subjects harboured their unique genotypes. None of the investigated factors could explain the differences in the intra-familial distribution of mutans streptococci. The pattern of similar genotypes in these Chinese families differs from that reported for western families.

Secondary structure of anthrax lethal toxin proteins and their interaction with large unilamellar vesicles: a fourier-transform infrared spectroscopy approach.

Attenuated total reflection Fourier transform infrared spectroscopy has been used to study the secondary structure of anthrax lethal toxin proteins: protective antigen (PA) and lethal factor (LF), as a function of pH in the absence and in the presence of phospholipid vesicles. We first characterized the binding of LF and PA to the lipid membrane and demonstrated the strong pH dependence of the association of PA and LF to the lipid bilayer as well as the effect of pH neutralization on this binding. Binding of LF to the lipid membrane can be, at least partially, reversed when the pH is brought to neutral whereas in the same conditions PA binding is irreversible. Characterization of the conformational changes undergone by PA and LF upon pH lowering, lipid binding, and, in the case of LF, reversal of binding was carried out (i) by determining the secondary structure of the proteins and (ii) by evaluating their ability to undergo an hydrogen/deuterium exchange.

Structure and interaction of PA63 and EF (edema toxin) of Bacillus anthracis with lipid membrane.

The secondary structures of the two components of the Bacillus anthracis edema toxin, protective antigen (PA63) and edema factor (EF), as well as the two EF mutants: CYA30 (containing the N-terminal PA63-binding domain) and CYA62 (containing the C-terminal catalytic domain) were investigated as a function of pH in the absence and in the presence of phospholipid vesicles using attenuated total reflection Fourier transform infrared spectroscopy. Secondary structures were independent of pH, whereas, in all cases, structural modifications were observed upon lipid binding. The ability of PA63 and EF to undergo hydrogen/deuterium exchange was evaluated. The binding of these proteins and the mutants to the lipid membrane was also characterized and it was demonstrated that the association of PA63 to the lipid bilayer was pH-dependent, while the binding of EF to the lipid membrane took place at both neutral and acidic pH. Interestingly, the two EF mutants are showing different lipid binding properties in response to pH: CYA30 has a strong pH-dependence whereas CYA62, as EF, binds to the lipid vesicles at all pHs. For the two proteins characterized by a pH-dependent lipid binding, the reversibility of binding upon neutralization was tested and binding of PA63 to the membrane was found to be irreversible whereas that of CYA30 was reversible.

Structure and interaction of VacA of Helicobacter pylori with a lipid membrane.

In its mature form, the VacA toxin of Helicobacter pylori is a 95-kDa protein which is released from the bacteria as a low-activity complex. This complex can be activated by low-pH treatment that parallels the activity of the toxin on target cells. VacA has been previously shown to insert itself into lipid membranes and to induce anion-selective channels in planar lipid bilayers. Binding of VacA to lipid vesicles and its ability to induce calcein release from these vesicles were systematically compared as a function of pH. These two phenomena show a different pH-dependence, suggesting that the association with the lipid membrane may be a two-step mechanism. The secondary and tertiary structure of VacA as a function of pH and the presence of lipid vesicles were investigated by Fourier-transform infrared spectroscopy. The secondary structure of VacA is identical whatever the pH and the presence of a lipid membrane, but the tertiary structure in the presence of a lipid membrane is dependent on pH, as evidenced by H/D exchange.