Oral cancer cell to endothelial cell communication via exosomal miR-21/RMND5A pathway

Required for meiotic nuclear division 5 homolog A (RMND5A), a novel ubiquitin E3 Ligase, has been reported to correlate with poor prognosis of several cancers. However, its role in endothelial cells has not been reported. In this study, overexpression of RMND5A in human umbilical vein endothelial cells (HUVECs) was performed via lentiviral infection, followed by MTT, would healing and tube formation assay as well as signaling analysis. Moreover, crosstalk between HUVECs and oral squamous cell carcinoma (OSCC) cells was investigated by indirect co-culture with condition medium or tumor cell derived exosomes. Our results showed that overexpression of RMND5A reduced the proliferation, migration and tube formation ability of HUVECs by inhibiting the activation of ERK and NF-κB pathway. Interestingly, OSCC cells can inhibit RMND5A expression of endothelial cells via exosomal miR-21. In summary, our present study unveils that OSCC cells can activate endothelial cells via exosomal miR-21/RMND5A pathway to promote angiogenesis, which may provide novel therapeutic targets for the treatment of OSCC.

[Enamel developmental defects: environmental factors and clinical management]

Enamel formation is a complex physiological process that depends on the coordinated regulation of multiple mechanisms. This process is quite sensitive to various local and systemic interference factors. Therefore, during the long period from the embryonic stage to adolescence or even adulthood, various interference factors may lead to enamel developmental defects. Among them, early life is the most sensitive stage to environmental factors exposure, while it is also the critical period of enamel development of deciduous and permanent teeth. Environmental factors exposure during this period often leads to varying degrees of enamel development defects. In this review, we generalize the research progress of environmental factors affecting enamel developmental defects, summarize the potential mechanisms of environmental factors leading to enamel developmental defects, and conclude the clinical management strategies based on tertiary prevention. This work hopes to provide a theoretical basis for preventing abnormal teeth development from the critical time window of early life, propose eugenics health consultation and promote children 's oral health management.

Is it safe and effective to extract impacted maxillary tooth adjacent to maxillary sinus via submaxillary sinus membrane space approach?-a randomized controlled trial

OBJECTIVE

To evaluate the clinical outcomes following extraction of impacted maxillary tooth adjacent to maxillary via submaxillary sinus membrane space approach.

MATERIALS AND METHODS

Seventy-two patients were enrolled in our study. The positions of the maxillary impacted tooth were confirmed by cone-beam computed tomography (CBCT). Cases were randomly divided into two groups: the "submaxillary sinus membrane space approach" was applied in the new method (NM) group, and the conventional "avoid maxillary sinus membrane exposure" strategy was executed in the traditional method (TM) group. The clinical and follow-up data were recorded.

RESULTS

The duration of the procedure in the TM group was significantly longer than those in the NM group (P < 0.05). Four teeth were accidentally displaced into the maxillary sinus with MSM perforation. The MSM perforation rate was slightly higher in the TM group than in the NM group, however, without significant difference between the two groups (8/36 vs. 3/36, P = 0.19). The maxillary sinus membrane perforation was associated with the displacement of tooth into the maxillary sinus (OR = 16.2, P = 0.026). The root tip exposure of the adjacent tooth was significantly higher in the TM group than in the NM group (10/36 vs. 1/36, P = 0.006). The incidence of reduced pulp vitality of the adjacent tooth was significantly higher in the TM group (10/36 vs. 1/36, P = 0.006), and it was associated with the exposure of the root tip intraoperatively (OR = 456.5, P < 0.001). The incidence of external root resorption was significantly lower in the NM group, and there was no significant association with the root exposure intraoperatively (OR = 3.7, P = 0.47).

CONCLUSIONS

Submaxillary sinus membrane space approach is a safe and efficient approach in extraction of impacted maxillary tooth. It is an alternative way for cases which are in close proximity to the maxillary sinus.

CLINICAL RELEVANCE

A novel method to extract impacted maxillary tooth adjacent to maxillary sinus.

[Expert consensus on the biobank development of oral genetic diseases and rare diseases and storage codes of related biological samples from craniofacial and oral region]

The biological samples of oral genetic diseases and rare diseases are extremely precious. Collecting and preserving these biological samples are helpful to elucidate the mechanisms and improve the level of diagnose and treatment of oral genetic diseases and rare diseases. The standardized construction of biobanks for oral genetic diseases and rare diseases is important for achieving these goals. At present, there is very little information on the construction of these biobanks, and the standards or suggestions for the classification and coding of biological samples from oral and maxillofacial sources, and this is not conducive to the standardization and information construction of biobanks for special oral diseases. This consensus summarizes the background, necessity, principles, and key points of constructing the biobank for oral genetic diseases and rare diseases. On the base of the group standard "Classification and Coding for Human Biomaterial" (GB/T 39768-2021) issued by the National Technical Committee for Standardization of Biological Samples, we suggest 76 new coding numbers for different of biological samples from oral and maxillofacial sources. We hope the consensus may promote the standardization, and smartization on the biobank construction as well as the overall research level of oral genetic diseases and rare diseases in China.

[Effects of prenatal nicotine exposure on enamel formation of offspring mice]

Objective: To investigate the effects of nicotine on the morphology, structure of offspring's dental germ, enamel organ and other dental tissues and the further potential epigenetic mechanisms by establishing prenatal nicotine exposure mouse model. Methods: Ten C57BL/6 pregnant mice were randomly divided into control group (physiological saline subcutaneous injection) and prenatal nicotine exposure (PNE) group (nicotine subcutaneous injection) by using a random number table. Postnatal day 0 (P0), postnatal day 14 (P14) and postnatal day 25 (P25) offspring mice were collected for subsequent experiments. The offspring mice were divided into offspring control group and offspring PNE group according to the maternal group respectively. Weights of P0 and P25 offspring mice were recorded. Micro-CT, scanning electron microscope (SEM) and Vickers hardness test were performed to analyze the related parameters of hard tissues including alveolar bones and mandibular incisors. Total RNAs were extracted from mandible tissues and the third generation of dental epithelial stem cells (DESC) in P25 mice. The relative expression levels of osteogenic and ameloblastic differentiation related genes were measured by real-time quantitative PCR (RT-qPCR). Immunohistochemical stainings of paraffin sections were then performed to observe the distribution and expression level of proliferating cell nuclear antigen (Pcna), amelogenin (Amelx), histone H3 trimethylated at lysine 27 (H3K27me3) and enhancer of zeste homolog 2 (Ezh2). Cell counting kit-8 (CCK-8) assays were used to detect the cell viabilities of DESCs after administrations of different concentrations of nicotine (0.01, 0.1, 1 mmol/L) and GSK126 (an inhibitor of histone methyltransferase Ezh2). Results: Compared with the control group, pregnant mice in PNE group were more likely to have adverse pregnancy outcomes, such as significantly lower offspring body weight [P0: offspring control (1.20±0.04) g, offspring PNE (0.99±0.02) g, P<0.001; P25: offspring control (15.26±1.70) g, offspring PNE (9.65±1.32) g, P<0.001] and increased stillbirths rate [offspring control (0), offspring PNE (46.40±9.30) %, P<0.001]. At P14 and P25, the distance parameters between the enamel mineralized deposits of mandibular incisors and the mesial surface of the first molar in offspring PNE group [P14: (-1 349±45) μm; P25: (-1 192±147) μm] was significantly decreased compared with the control group [P14: (-506±380) μm, P25: (504±198) μm] (P<0.05, P<0.001). The enamel column and enamel column stroma of incisors in offspring PNE group were blurred, arranged loosely and disorderly than those in the control group, while the microhardness of incisor enamel in offspring PNE group [(245.7±18.4) MPa] was significantly lower compared to the control group [(371.9±28.7) MPa] (P<0.001). HE staining showed disordered pre-ameloblast (Pre-Am) arrangement and delayed mineralization deposition point in offspring PNE group compared with the control group, while the length of transit-amplifying cell (TA) and Pre-Am region were prolonged as well. Immunohistochemical staining results displayed that the overall Pcna (P<0.05), H3K27me3 (P<0.01), Ezh2 (P<0.01) expression of labial cervical loop (LaCL) in PNE group were increased, while the positive signal of Amelx in ameloblast cytoplasm was impaired. In vitro, the addition of 1 mmol/L nicotine could significantly upregulate the expression level of Pcna (P<0.01) and downregulate the expression levels of B lymphoma Mo-MLV insertion region 1 (P<0.05), leucine rich repeats and immunoglobulin like domains 1 (P<0.05), Amelx (P<0.01). In addition, 1 mmol/L nicotine could also significantly enhance the proliferation activity of DESCs (P<0.001). Addition of 10 μmol/L GSK126, could rescue the proliferation activation effect of 1 mmol/L nicotine on DESCs. Conclusions: PNE may delay the process of enamel formation and lineage differentiation, leading to the abnormal proliferation of DESCs and changes of epigenetic modification state in H3K27me3, which affect the development of enamel in offspring mice,suggesting PNE might be one of risk environmental factor for tooth development.

[Epigenetic regulation mechanism: roles in enamel formation and developmental defects of enamel]

Enamel formation is a series of complex physiological processes, which are regulated by critical genes spatially and temporally. These processes involve multiple developmental stages covering ages and are prone to suffer signal interference or gene mutations, ultimately leading to developmental defects of enamel (DDE). Epigenetic modifications have important regulatory roles in gene expression during enarnel development. New technologies including high-throughput sequencing, chromatin immunoprecipitation sequencing (ChIP-seq), and DNA methylation chip are emerging in recent years, making it possible to establish genome-wide epigenetic modification profiles during developmental processes. The regulatory role of epigenetic modification with spatio-temporal pattern, such as DNA methylation, histone modification and non-coding RNA, has significantly expanded our understanding of the regulatory network of enamel formation, providing a new theoretical basis of clinical management and intervention strategy for DDE. The present review briefly describes the enamel formation process of human beings' teeth as well as rodent incisors and summarizes the dynamic characteristics of epigenetic modification during enamel formation. The functions of epigenetic modification in enamel formation and DDE are also emphatically discussed.

[Identification and preservation of arm lymphatics in axillary lymph node dissection to prevent arm lymphedema: a single center randomized controlled trial]

Objective: To evaluate the feasibility of identification and preservation of arm lymphatics (DEPART) in axillary lymph node dissection (ALND) for breast cancer to prevent arm lymphedema. Methods: A randomized controlled study method was used. Two hundred and sixty-five patients who underwent breast cancer surgery at the Department of Thyroid and Breast Surgery, Zhongnan Hospital of Wuhan University from November 2017 to June 2018 were included, and the patients were randomly divided into ALND+ DEPART group (132 patients) and standard ALND group (133 patients) by random number table method. In the ALND+ DEPART group, indocyanine green and methylene blue were injected as tracers before surgery, and the arm sentinel nodes was visualized by staged tracing during intraoperative dissection of axillary lymph nodes. Partial frozen sections were made of arm lymph nodes >1 cm in length and hard and suspicious of metastasis, and arm lymph nodes and lymphatic vessels were selectively preserved. Patients in the standard ALND group underwent standard ALND. Objective and subjective indexes of arm lymphedema were evaluated by 5-point circumference measurement and Norman questionnaire. Results: Among 132 breast cancer patients in the ALND+ DEPART group, 121 (91.7%) completed DEPART. There were no statistically significant differences in age, body mass index, pathological type, dissection number of axillary lymph node, N stage, TNM stage, molecular typing, and regional radiotherapy between the ALND+ DEPART and standard ALND groups (P>0.05). At a median follow-up of 24 months, assessment by the 5-point circumference measurement showed that the incidence rates of lymphedema in the ALND+ DEPART and standard ALND groups were 5.0% (6/121) and 15.8% (21/133), respectively, with statistically significant differences (P=0.005). Assessment by the Norman questionnaire showed that the incidence rates of lymphedema in the ALND+ DEPART and standard ALND groups were 5.8% (7/121) and 21.8% (29/133), respectively, with a statistically significant difference (P<0.001). No local regional recurrence was observed in either group during the follow-up period. Conclusion: For breast cancer patients with positive axillary lymph nodes, the administration of DEPART during ALND can reduce or avoid the occurrence of arm lymphedema without compromising oncology safety.

[Lesion removal plus whole breast exploration and washing plus micro-plastic procedures in the treatment of granulomatous lobular mastitis: a randomized controlled study]

Objective: To examine the effect of"lesion removal plus whole breast exploration and washing plus micro-plastic surgery"in granulomatous lobular mastitis. Methods: A single-center prospective randomized controlled study method was used to enroll patients diagnosed with granulomatous lobular mastitis for whom surgical procedures were projected from March 2017 to September 2019 at Department of Thyroid and Breast Surgery, Zhongnan Hospital of Wuhan University. The sample size is determined by the superiority test. Based on the literatures and the previous work, the two groups require 97 cases. Fifty-two patients underwent"lesion removal+whole breast exploration and washing plus micro-plastic surgery"(observation group). Forty-five cases underwent"empirical breast lesion resection plus fascia tissue flap plasty plus nipple and areola correction"(control group). The primary study endpoint is the recurrence rate, and the secondary study endpoints include surgical complications, incision healing time, and postoperative patient satisfaction. Independent sample t test, Wilcoxon rank-sum test, χ² test and Fisher exact test were used for comparison between groups. Results: All procedures were completed successful, with no severe complications. All patients were followed up for (15.2±1.9) months (range: 12 to 24 months). There were no significant differences in incidence of postoperative complications (7.7% (4/52) vs. 6.7%(3/45), P=1), drainage time ((8.6±0.6) days vs. (8.4±0.8) days, t=1.921, P=0.053) and hospital stay ((7.7±0.6) days vs. (7.6±0.5) days, t=1.633, P=0.102) between the two groups. The recurrence rate of the observation group was lower significantly than that of the control group (3.8% (2/52) vs. 24.4%(11/45), χ²=8.819, P=0.003). The observation group had better cosmetic effects (Z=-2.657, P=0.008) and patient satisfaction than control group (Z=-5.730, P=0.000). Conclusion: The "lesion removal plus whole breast exploration and flushing plus micro-plastic surgery" has a good therapeutic effect and cosmetic value for patients with refractory granulomatous lobular mastitis.

[Application value of intraoperative neuromonitoring plus "classification of EBSLN" to protect the external branch of the superior laryngeal nerve]

Objective: To investigate the application efficacy of the "classification of external branch of superior laryngeal nerve (EBSLN)" combined with intraoperative neuromonitoring (IONM) in the dissection of EBSLN for protecting the nerve from injuery, compared with ligation of branches of the superior thyroid vessels without attempts to visually identify the nerve. Methods: A prospective randomized controled study was performed in our center. Patients subjected to thyroidectomy from January 2017 to June 2019 were randomly divided into 2 groups, patients in experimental group underwent thyroidectomy and "classification of EBSLN" with IONM to dissect EBSLN, and patients in control group received synchronous surgery without attempts to visually identify the nerve. The anatomical subtypes of EBSLN in experimental group were recorded. The voice handicap index 10 (VHI-10) score was evaluated and the movement of bilateral vocal cords was examined by laryngoscope before surgery, 1 month, 3 months, and 6 months after surgery, respectively. SPSS 26.0 statistical software was used for statistical analysis. Results: Among the 1 377 EBSLN from 827 patients (317 males and 510 females, aged 24-58 years old), 691 EBSLNs in experimental group and 686 EBSLNs in control group. Totally 98.3% of EBSLNs in experimental group were identified by IONM including 16.4% (113/691) for type Ⅰ, 21.3% (147/691) for type Ⅱa, 31.4% (217/691) for type Ⅱb, 10.4% (72/691) for type Ⅲa, 3.9% (27/691) for type Ⅲb, 16.6% (115/691) for type Ⅲc. There was no statistical significance difference in baseline data between 2 groups (all P>0.05). All patients were followed up for more than 6 months. The postoperative nerve injury rate of experimental group was significantly lower than that of control group (1.2% vs. 7.5%, χ²=12.659, P<0.001), and the VHI-10 scores and laryngoscope results of experimental group were better than those of control group in three follow-up visits (P<0.001). With postoperative laryngoscope examination, 3 patients in the experimental group and 23 patients in the control group showed vocal cord relaxation, bilateral oblique asymmetry and other phenomena, which were considered as the results of permanent injury. Other patients with symptoms were relieved to varying degrees during the follow-up, and their symptoms were considered as the results of temporary injury. Conclusion: IONM combined with "classification of EBSLN" can reduce significantly the risk of EBSLN injury in thyroidectomy, which is better than direct ligation of branches without attempts to visually identify the nerve.

[Parathyroid hormone assay with eluent of aspirated tissues in parathyroidectomy]

Objective: To explore the values of intraoperative fine-needle aspiration (IFNA) and parathyroid hormone (PTH) detection in the eluate of aspirated tissue during parathyroidectomy. Methods: Fifty-four patients with secondary hyperparathyroidism (SHPT) including 24 males and 30 females, aged 20-83 years, admitted to Zhongnan Hospital of Wuhan University from January 2019 to October 2019, were included. All patients received subtotal parathyroidectomy with autologous transplantation, during surgery, IFNA and PTH detection in the eluate of aspirated tissue were performed, and also routine postoperative pathological examination was performed. The results of PTH detection in the eluate of aspirated tissue and postoperative pathological examinations were compared and analyzed by SPSS and R software for evaluating of the sensitivity, specificity, positive predictive value, negative predictive value, misdiagnosis rate, missed diagnosis and accuracy. Results: Surgery was completed successfully in all patients. After surgery, the symptoms were improved in the patients except two who were asymptomatic. None had any serious postoperative complications such as hypocalcaemia or hoarseness. A total of 231 aspirated tissue samples were tested, of which 216 were identified as parathyroid and 15 non-parathyroid based on intraoperative PTH detection in tissue eluate; while 217 were confirmed as parathyroid tissues and 14 non-parathyroid tissues with postoperative pathological examinations. The specificity and sensitivity of intraoperative IFNA and PTH detection in tissue eluate for identifying parathyroid tissues were 99.5% and 100.0%, respectively. Conclusion: The IFNA and PTH detection in tissue eluate is a rapid, simple, and accurate procedure, which helps the surgeon to identify parathyroid tissue and to ensure the endocrine activity of preserved or autografted parathyroid tissue during parathyroidectomy.

[Clinical effects of artificial dermis combined with vacuum sealing drainage and autologous split-thickness skin graft in repair of scar contracture deformity after extensive burn]

Objective: To explore the clinical effects of artificial dermis combined with vacuum sealing drainage (VSD) and autologous split-thickness skin graft in repair of scar contracture deformity after extensive burn. Methods: A total of 8 patients with scar hyperplasia and contracture deformity on joint after healing of extensive burn were admitted to our hospital from August 2015 to August 2017. There were 5 females and 3 males aged 8 to 45 years with an average of 23 years. In the first stage operation, scar tissue on contracture site was removed, and the wound was covered by artificial dermis followed by continued VSD treatment. On 10-14 d after the first stage operation, the artificial dermis tissue formed, and the second stage autologous split-thickness skin grafting and continued VSD treatment were performed. Routine anti-scar therapy was carried out after healing of wounds. Time of wound healing after the second stage operation was recorded. Colour and texture of the split-thickness skin graft, scar formation condition of the donor site, and action condition of the operation site during follow-up were observed. Results: The wounds of 8 patients were healed in 10-14 d after the second stage operation. During follow-up of 6-24 months, the split-thickness skin graft was with smooth surface and good elasticity, and the function of joint recovered well. The donor site in head healed well with no scar. Only pigmentation was left in the donor site of thigh, and scar was not obvious. The patients and their family members were satisfied. Conclusions: After application of artificial dermis combined with VSD and autologous split-thickness skin graft in repair of scar contracture deformity after extensive burn, the skin grafting area and donor site were with unobvious scar hyperplasia, and the joint function in the operation area was good.

[Analysis of chromosome in 1 324 patients with oligozoospermia or azoosperm]

OBJECTIVE

To explore the incidience of chromosome abnormality of the patients with oligozoospermia or azoospermia and male infertility, to discuss the relationship between the quantitative and structural abnormality of chromosome and to lay the foundation for the clinical diagnosis and consultation.

METHODS

A retrospective analysis was conducted from January 1, 2015 to May 1, 2016, in the Center for Reproduction Medicine, the Second Hospital of Jilin University, with male reproductive abnormalities history excluded. In the study, 1 324 cases were included with 448 cases of azoospermia and 876 cases of oligozoospermia. All the patients through ultrasound examination, color Doppler ultrasonography, the seminal plasma Zn determination, their hormone level determination, chromosome karyotype (the perinatal blood samples were obtained from the 1 324 patients with oligozoospermia or azoospermia for lymphocyte culture, then chromosomal specimens were prepared, G-banding analyses combined with clinical data were used to statistically analyze the incidence of chromosomal abnormality), Y chromosome azoospermia factor [PCR technique was used to detect SY157 locus, SY254 locus, and SY255 locus in male Y chromosome azoospermia factor (AZF) gene of the patients with oligozoospermia or azoospermia]. The relationship between chromosome abnormalities and oligozoospermia or azoospermia were analyzed.

RESULTS

Among the 876 cases of oligospermia patients, 78 cases were chromosome number abnormality and chromosomal structural abnormality, the abnormal number of sex chromosomes in 22 cases, and sex chromosomes and chromosome structural abnormalities in 56 cases; in the 448 cases of azoospermia patients, 91 cases were chromosomal structural abnormality and chromosome number abnormality, of them, 78 cases were of abnormal number of sex chromosomes, and 13 cases were of abnormal structure. In addition, 137 cases were of chromosome polymorphism in all the 1 324 patients, The incidence of Y chromosome abnormality in azoospermatism was higher than that of the 43 patients with Y chromosome AZF microdeletion. In addition, the asthenospermia and recurrent spontaneous abortion were closely related to Y chromosome abnormality and the chromosome translocations and inversions.

CONCLUSION

Oligozoospermia and azoospermia patients with abnormal chromosome karyotype have high incidence rate, and chromosome karyotype analyses were carried out on it, which is conducive to clinical diagnosis for the patients with abnormal chromosome karyotype. There is a close relationship between male infertility and abnormal karyotype. It is conducive to clinical diagnosis for the patients with infertility through chromosome karyotye analysis, which also provides evidence for genetic counseling.

[A complex chromosome translocation with male infertility of karyotype analysis and literature review]

One case of family chromosomal karyotype with complex chromosomal translocation and male infertility was reported. This case is a male, 30 years old, Han nationality, who did not receive contraception for 3 years after marriage. The phenotype and intelligence of the patients were normal, and there were no abnormalities in the external genitalia. No abnormalities were found in the prostate and spermatic vein. There was no history of parotitis or testicular trauma, no history of smoking, drinking history, denial of harmful substances and history of radioactive contact. There were no similar patients in the family, and the secondary sex was normal. The routine semen examination suggested that the active sperm was seldom seen. There were no obvious abnormalities in the serum endocrine examination of the patient. Cytogenetic examination: the patient's karyotype 46XY, t (10; 18; 21) (q22; p11.2; q11.2). There was no deletion in locus sY84, sY86, sY127, sY134, sY143, sY254 and sY255. His wife's examination showed no obvious abnormality, and her karyotype was normal. The parents of the patients were not close relatives. Their father's chromosome karyotype analysis was 46, XY, and Y chromosome microdeletion was normal. The chromosome karyotype of the parent was 46XX, t (10; 18; 21), and the parents of the patient also had a daughter, whose phenotype and intellectual development were normal, chromosome karyotype 46XX, t (10; 18; 21). In this case, the patient's balance translocation should be inherited by the mother. Because of the normal phenotype of the patient, there was no loss of genetic material, but the abnormal chromosomes might be passed to the offspring, and the proportion of the unbalanced gametes was very high. Through systematic review and review of the cases, it was concluded that the balanced translocation carriers only changed the relative position of the translocation segments on the chromosomes, retained the total number of the original genes, only changed the relative position of the genes on the chromosomes, and had no serious effect on the role of the gene and the development of the individual. The phenotype was normal. The patients were given symptomatic treatment to improve semen quality. It is recommended that pre-implantation genetic screening/diagnosis(PGS/PGD) be performed if necessary. It is to guide married men and women to choose the appropriate childbearing age, avoid unhealthy environmental contacts, and strengthen genetic screening before and after pregnancy, so as to achieve the goal of eugenics.

Deformation and fracture of K3 rotary nickel-titanium endodontic instruments after clinical use

AIM

The aim was to evaluate the incidence and type of defects that occurred with K3 rotary nickel-titanium instruments during routine clinical use.

METHODOLOGY

A total of 2397 K3 (G-PACKS, SybronEndo, West Collins, Orange, CA, USA) instruments were collected from a graduate endodontic clinic over 21 months. All the instruments were limited to a maximum use of 30 canal preparations. The collected instruments were measured by a digital caliper to determine whether any fractures had occurred and then were visually inspected for deformation and fracture under a stereomicroscope. The surfaces of fractured instruments were further evaluated under a scanning electron microscope. Data were analysed using chi-square test and Kruskal-Wallis test.

RESULTS

The incidence of instrument defect was 5.63%, consisting of 3.59% fractures and 2.05% deformations. The defect rates of 0.04 and 0.06 files were statistically higher than the other taper groups (P < 0.003) except for 0.08 files (P > 0.05). For the fractured instruments, 63.95% failed from flexural fatigue, whilst 36.05% failed from torsion.

CONCLUSION

Flexural fracture was the major mode of fracture for instruments with larger taper. A routine check for instrument integrity particularly for 0.04 and 0.06 files at high magnification is recommended after each clinical use.

Oral health status of chinese paediatric and adolescent oncology patients with chemotherapy in Hong Kong: a pilot study

Aim:

To study the oral health status of Chinese children and adolescents undergoing chemotherapy in Hong Kong.

Method:

All Chinese children and adolescent oncology patients aged 18 or below attending the Children's Centre for Cancer and Blood Disease at a hospital for chemotherapy were invited and parental consent was sought before they were accepted into the study. The study comprised of 1) a parental questionnaire, 2) the collection of medical history and 3) a clinical examination for tooth decay (caries) and mucosal status.

Results:

A total of 69 patients were invited, and they all participated in this study. Their mean age was 9.2±5.0 and 44 (64%) were males. Twenty-six patients (38%) had no caries experience (DMFT and/or dmft = 0). Higher caries experience was detected in participants that were not born in Hong Kong, had completed active chemotherapy, participated in school dental care service and whose parents had low educational levels. There were 41 patients with active chemotherapy, 24 of whom were diagnosed with acute leukaemia, 5 with haematological malignancies other than leukaemia and 11 with solid tumours. Antimetabolites, cytotoxic antibiotics, alkylating agents and plant alkaloids were administered in 49%, 32%, 24% and 22% of them, respectively. Twenty-six (63%) patients showed no mucosal complications. The most common oral complication was oral mucositis (24%) followed by petechiae (10%).

Conclusion:

About two-thirds of paediatric and adolescent cancer patients had caries experience, which was more common among those who had completed chemotherapy. Oral mucositis followed by petechiae were the two most common complications of receiving chemotherapy.

Cytotoxicity of ammonium hexafluorosilicate on human gingival fibroblasts

Ammonium hexafluorosilicate (SiF), which is claimed to significantly improve occlusion of dentinal tubules, was proposed as a novel desensitizer for dentine hypersensitivity (DH). However, the cytotoxicity of SiF on oral cells is lacking. The purpose of this study was to investigate the cytotoxicity of SiF on human gingival fibroblasts (hGFs) under different dosages (0.001%, 0.01%, 0.1%, and 1%) and treatment durations (1, 5, 10, and 30min). Cell proliferation, mitochondrial membrane potential (MMP) and cell cycle were tested by MTT assay, JC-1 staining and flow cytometry, respectively. Glutathione (GSH) depletion was analyzed to further investigate the underlying mechanism of SiF-induced cytotoxicity. MTT assay showed that there was significantly lower number of viable cells when the hGFs were treated with 0.01% (10min), 0.1% (10 and 30min) and 1% (5, 10, and 30min) SiF than the control group (p<0.05). MMP decreased and GSH depletion increased dramatically along with higher concentrations (0.1% and 1% SiF) and prolonged times (10 and 30min). DNA synthesis [S (%)] of cells treated with 0.1% and 1% SiF (5, 10, and 30min) was significantly lower than the control group (p<0.05). Our results indicate exposure to up to 0.01% SiF for less than 5min causes low or no cytotoxicity in vitro.

Neuropeptide Y in black seabream Acanthopagrus schlegelii: identification, distribution and mRNA expression responses to ghrelin

The coding region of neuropeptide Y (NPY) complementary (c)DNA was cloned from the hypothalamus RNA of black seabream Acanthopagrus schlegelii, including 297 bp coding for prepro-NPY of 98 amino acids. Real-time reverse transcriptase-polymerase chain reaction was performed to determine A. schlegelii npy gene expression; NPY messenger RNA (mRNA) was expressed highly in the brain and stomach. Treatment with acylated ghrelin significantly up-regulated NPY mRNA level in the hypothalamus, suggesting that NPY may be involved in regulating food intake of A. schlegelii.

Influence of nicotine on blood perfusion and bone healing during distraction osteogenesis

Nicotine is the main chemical component in tobacco products and its effect on bone healing remains controversial. This study aims to evaluate the influence of nicotine on blood perfusion and bone healing using a rabbit model of mandibular distraction osteogenesis. The dose dependent effect of nicotine on bone regeneration, and the effect of nicotine on blood perfusion and angiogenesis were assessed by radiography, micro-computed tomography, histological and immunohistochemical analysis, real time PCR and Laser Doppler monitoring. Results showed that bone healing was compromised by high dose nicotine treatment. Nicotine exposure increased microvessel density, whereas inhibited blood flow and bone formation. The expression of bone morphogenetic protein (BMP)-2 in osteoblasts was also decreased. The present study supported that nicotine has a dose dependant influence on bone healing in distraction osteogenesis. Nicotine compromises bone regeneration possibly by causing ischemia and inhibiting BMP expression in osteoblasts. Nicotine exposure enhances angiogenesis but can not compensate for the adverse effect of vasoconstriction.

EDAP piezoelectric shock wave lithotripsy for gallbladder stones

EDAP piezoelectric shock wave lithotripsy combined with oral ursodeoxycolic acid dissolution of stones was used to treat 1055 patients with gallbladder stones. 926 of them (87.8%) were followed up for more than 1 year. The patients were divided into two groups: Group I, 637 patients with functioning gallbladders containing one radiolucent stone less than or equal to 20 mm in diameter or 2 to 3 stones each less than or equal to 12 mm, and Group II: 289 patients with stones exceeding the above criteria. The stone fragmentation rate was 96.2% and 94.1% respectively in Group I and in Group II. Gallbladder stones disappeared in 18.5%, 35.0%, 46.2% and 52.4% of the patients in Group I in 1, 3, 6, and 12 months after treatment and 7.3%, 11.4%, 20.1%, and 27.7% in Group II. The treatment was more effective for solitary stones less than or equal to 20 mm in diameter. No serious complications were noted. The midterm curative effect was satisfactory. Further study is required to raise the curative effect and prevent stone recurrence.

Extracorporeal shock wave lithotripsy. Experience in treating 245 patients with gallbladder stones

An EDAP LT-01 lithotripter was used to treat 245 patients with functioning gallbladders containing one to three radiolucent stones of less than 20 mm in diameter. Ursodeoxycholic acid was administrated as adjuvant litholytic therapy. The gallbladder stones disintegrated in 98.8% of patients and disappeared completely in 21.2% within 1 month after lithotripsy, in 26.5% within 2 months, in 33.9, 40, 46.5, 48.6 and 53.9% within 3, 4, 6, 9, and 12 months, respectively. Adverse effects after lithotripsy were dull abdominal pain (49.4%), biliary colic (13.1%), jaundice (1.2%), and pancreatitis (0.4%). Extracorporeal shock wave lithotripsy combined with litholytic therapy is a non-invasive, painless, safe, and effective treatment in selected patients. Patients with solitary radiolucent stone less than 20 mm in diameter are considered candidates for extracorporeal shock wave lithotripsy (ESWL). The key to success of ESWL lies in the strict selection of patients, careful monitoring throughout the lithotriptic procedure, and enough litholytic therapy. The disadvantages of this method include strict selection of patients and high costs, poor curative effect, and recurrence of stones (11.4% of patients).