T cells participate in bone remodeling during the rapid palatal expansion.

Palatal expansion has been widely used for the treatment of transverse discrepancy or maxillae hypoplasia, but the biological mechanism of bone formation during this procedure is largely unknown. Osteoclasts, which could be regulated by T cells and other components of the immune system, play a crucial role in force-induced bone remodeling. However, whether T cells participate in the palatal expansion process remains to be determined. In this study, we conducted the tooth borne rapid palatal expansion model on the mouse, and detect whether the helper T cells (Th) and regulatory T cells (Treg) could affect osteoclasts and further bone formation. After bonding open spring palatal expanders for 3-day, 5-day, 7-day, and retention for 28-day, micro-computed tomography scanning, histologic, and immunofluorescence staining were conducted to evaluate how osteoclasts were regulated by T cells during the bone remodeling process. We revealed that the increased osteoclast number was downregulated at the end of the early stage of rapid palatal expansion. Type 1 helper T (Th1) cells and Type 17 helper T (Th17) cells increased initially and promoted osteoclastogenesis. Thereafter, the regulatory T (Treg) cells emerged and maintained a relatively high level at the late stage of the experiment to downregulate the osteoclast number by inhibiting Th1 and Th17 cells, which governed the new bone formation. In conclusion, orchestrated T cells are able to regulate osteoclasts at the early stage of rapid palatal expansion and further facilitate bone formation during retention. This study identifies that T cells participate in the palatal expansion procedure by regulating osteoclasts and implies the potential possibility for clinically modulating T cells to improve the palatal expansion efficacy.

Neural EGFL-Like 1 Regulates Cartilage Maturation through Runt-Related Transcription Factor 3-Mediated Indian Hedgehog Signaling.

The pro-chondrogenic function of runt-related transcription factor 2 (Runx2) was previously considered to be dependent on direct binding with the promoter of Indian hedgehog (Ihh)-the major regulator of chondrocyte differentiation, proliferation, and maturation. The authors' previous studies identified neural EGFL like 1 (Nell-1) as a Runx2-responsive growth factor for chondrogenic differentiation and maturation. In this study, it was further revealed that the pro-chondrogenic activities of Nell-1 also rely on Ihh signaling, by showing: i) Nell-1 significantly elevated Ihh signal transduction; ii) Nell-1 deficiency markedly reduced Ihh activation in chondrocytes; and iii) Nell-1-stimulated chondrogenesis was significantly reduced by the specific hedgehog inhibitor cyclopamine. Importantly, the authors demonstrated that Nell-1-responsive Ihh signaling and chondrogenic differentiation extended to Runx2-/- models in vitro and in vivo. In Runx2-/- chondrocytes, Nell-1 stimulated the expression and signal transduction of Runx3, another transcription factor required for complete chondrogenic differentiation and maturation. Furthermore, knocking down Runx3 in Runx2-/- chondrocytes abolished Nell-1's stimulation of Ihh-associated molecule expression, which validates Runx3 as a major mediator of Nell-1-stimulated Ihh activation. For the first time, the Runx2→Nell-1→Runx3→Ihh signaling cascade during chondrogenic differentiation and maturation has been identified as an alternative, but critical, pathway for Runx2 to function as a pro-chondrogenic molecule via Nell-1.

Sexual dimorphism of estrogen-sensitized synoviocytes contributes to gender difference in temporomandibular joint osteoarthritis.

OBJECTIVES: Temporomandibular joint osteoarthritis (TMJOA) is approximately twice as prevalent in women than in men. Synoviocytes are believed to play a critical role in joint inflammation. However, it is unknown whether synoviocytes from different genders possess sexual dimorphisms that contribute to female-predominant TMJOA. MATERIALS AND METHODS: Freund's complete adjuvant combined with monosodium iodoacetate was used to induce TMJOA in female and male rats. Histologic and radiographic features were used to evaluate TMJOA. The expression of CD68, MCP-1, iNOS, and IL-1ß was detected by immunohistochemistry and real-time PCR. Primary fibroblast-like synoviocytes (FLSs) isolated from the synovial membrane of female and male rats were used for in vitro experiments. RESULTS: Female rats showed aggravated TMJOA features as compared to male rats. Increased expression of iNOS and IL-1ß was detected in synovial membrane from female TMJOA rats as compared to male rats. Furthermore, greater amounts of CD68-positive macrophage infiltration and increased MCP-1 expression around the synovial membrane were detected in female TMJOA rats compared to males. Primary cultured FLSs from female rats showed higher sensitivity to TNF-α treatment and recruited increased macrophage migration than male FLSs. More important, ovariectomy (OVX) by ablation in female rats repressed the sensitivity of female FLSs to TNF-α treatment due to the loss of estrogen production. Blockage of the estrogen receptor repressed estrogen-potentiated TNF-α-induced pro-inflammatory cytokine expression in OVX-FLSs. Moreover, the injection of estrogen receptor antagonists relieved the cartilage destruction and bone deterioration of TMJOA in female rats. CONCLUSION: Estrogen-sensitized synoviocytes in female rats may contribute to gender differences in the incidence and progression of TMJOA.

Amino acids at positions 3, 168, and 169 are associated with the ability of Nef proteins from HIV-1 CRF01_AE to downmodulate CD4.

Several HIV-1 subtypes are co-circulating among various high-risk groups in China, and an increasing prevalence of CRF01_AE was observed among MSM (men who have sex with men) within recent years. Patients infected with CRF01_AE may experience a more rapid disease progression than patients infected with non-CRF01_AE; however, the underlying mechanisms remains elusive. HIV-1 Nef is a multifunctional protein and plays critical roles in viral pathogenesis. Nef downregulates CD4 and human leukocyte antigen (HLA) to promote viral transmission and escape from the host immune response. In this study, we investigated the CD4 downmodulation activity of Nef proteins isolated from HIV-1 CRF01_AE and analyzed a potential relationship of Nef's capacity to downregulate CD4 with disease progression. We found that the majority of these Nefs from HIV-1 CRF01_AE efficiently downregulated CD4; Nefs with weaker CD4 downmodulation activity tended to be associated with higher CD4 levels and lower viral loads. Further elucidation revealed that amino acid residues at positions 3, 168, and 169 of CRF01_AE Nefs were associated with the capacity to downregulate CD4. Our data suggest that the capacity of Nef-mediated CD4 downregulation is not the only determinant for controlling disease progression, and other host and viral factors should be considered to explain the rapid disease progression of patients infected with HIV-1 CRF01_AE.

Estradiol promotes M1-like macrophage activation through cadherin-11 to aggravate temporomandibular joint inflammation in rats.

Macrophages play a major role in joint inflammation. Estrogen is involved in rheumatoid arthritis and temporomandibular disorders. However, the underlying mechanism is still unclear. This study was done to verify and test how estrogen affects M1/M2-like macrophage polarization and then contributes to joint inflammation. Female rats were ovariectomized and treated with increasing doses of 17ß-estradiol for 10 d and then intra-articularly injected with CFA to induce temporomandibular joint (TMJ) inflammation. The polarization of macrophages and expression of cadherin-11 was evaluated at 24 h after the induction of TMJ inflammation and after blocking cadherin-11 or estrogen receptors. NR8383 macrophages were treated with estradiol and TNF-α, with or without blocking cadherin-11 or estrogen receptors, to evaluate the expression of the M1/M2-like macrophage-associated genes. We found that estradiol increased the infiltration of macrophages with a proinflammatory M1-like predominant profile in the synovium of inflamed TMJ. In addition, estradiol dose-dependently upregulated the expressions of the M1-associated proinflammatory factor inducible NO synthase (iNOS) but repressed the expressions of the M2-associated genes IL-10 and arginase in NR8383 macrophages. Furthermore, estradiol mainly promoted cadherin-11 expression in M1-like macrophages of inflamed TMJ. By contrast, blockage of cadherin-11 concurrently reversed estradiol-potentiated M1-like macrophage activation and TMJ inflammation, as well as reversed TNF-α-induced induction of inducible NO synthase and NO in NR8383 macrophages. The blocking of estrogen receptors reversed estradiol-potentiated M1-like macrophage activation and cadherin-11 expression. These results suggested that estradiol could promote M1-like macrophage activation through cadherin-11 to aggravate the acute inflammation of TMJs.

Nonsurgical correction using miniscrew-assisted vertical control of a severe high angle with mandibular retrusion and gummy smile in an adult.

Orthodontic treatment in adult patients with a skeletal discrepancy can be challenging. In this case report, we achieved both sagittal and vertical control by combining the classic sliding mechanics straight-wire technique with miniscrew anchorage. We treated a 21-year-old Chinese woman with a severe high mandibular plane angle, a retrusive chin, and a gummy smile. Her diagnosis included a skeletal Class II skull base with a mild anterior open bite, a protrusive maxilla, and a backwardly rotated mandible. This case underscores the importance of anchorage control in both the sagittal and vertical directions. First, we used miniscrews in the maxillary and mandibular buccal segments to obtain rigid anchorage. Next, we achieved good anterior and posterior vertical control with miniscrews in the maxillary anterior labial and posterior buccolingual segments. Intrusion of the maxillary molars contributed to deepening of the anterior overbite and counterclockwise rotation of the mandibular plane, which, in turn, improved the facial profile. Intrusion of the maxillary incisors contributed to correction of the gummy smile. After 1 year of retention, the patient had a stable, well-aligned dentition with ideal intercuspation and an improved facial contour. Our results thus suggest that placement of miniscrews in the anterior and posterior regions of the maxilla is effective for camouflaging a high-angle skeletal Class II defect. This technique requires minimal patient compliance and is particularly useful for correction of a high angle in an adult with a gummy smile.

Miniscrew-assisted customized lingual appliances for predictable treatment of skeletal Class II malocclusion with severe deep overbite and overjet.

This report describes the use of miniscrew-assisted customized lingual fixed appliances in a patient with severe skeletal Class II malocclusion. The patient was a 12-year-old Chinese girl with the chief complaint of protrusive lips and anterior teeth. Her diagnosis included a skeletal Class II relationship with maxillary protrusion, a backward-rotated mandible, a full Angle Class II molar relationship, and severe deep overjet and overbite. Four premolars were extracted, and miniscrew anchorage was placed in the maxillary posterior lingual segment to provide maximum anchorage and to achieve vertical control of the intruding molars. The customized lingual fixed appliance and temporary anchorage devices created a smooth and invisible treatment progress, resulting ultimately in a well-aligned dentition with ideal intercuspation and a dramatically improved profile. The 3-year follow-up examination indicated that the excellent treatment outcome was stable.

Secreted phosphoprotein 24 kD (Spp24) inhibits growth of human pancreatic cancer cells caused by BMP-2.

The emerging role of bone morphogenetic proteins (BMPs) in the initiation and progression of multiple cancers has drawn great attention in cancer research. In this study, we report that BMP-2 can promote the proliferation of the pancreatic tumor cell line, PANC-1. Secreted phosphoprotein 24 kD (Spp24), a BMP binding protein, did not affect the proliferation of the cells but promoted the apoptosis of the cells in vitro. In a xeneograft tumor model using PANC-1 cells, BMP-2 dramatically promoted tumor growth, while Spp24 not only abolished the effect of BMP-2, but also dramatically induced tumor shrinking when used alone. Activation of Smad1/5/8 participated in this process as demonstrated by immunohistochemical staining of phosphorylated Smad 1/5/8. We conclude that Spp24 can be developed into a therapeutic agent that could be employed in clinical situations where the inhibition of BMPs and related proteins is advantageous.

Diverse forms of HIV-1 among Burmese long-distance truck drivers imply their contribution to HIV-1 cross-border transmission.

BACKGROUND: The China-Myanmar border is a particularly interesting region that has very high prevalence of and considerable diversity of HIV-1 recombinants. Due to the transient nature of their work, long-distance truck drivers (LDTDs) have a comparatively high potential to become infected with HIV-1 and further spread virus to other individuals in the area they travel within. In this study, we hypothesized that Burmese LDTDs crossing the China-Myanmar border frequently may potentially be involved in the cross-border transmission of HIV, and contribute to the extremely high prevalence of HIV-1 inter-subtype recombinants in this border region. METHODS: A molecular epidemiology study was conducted among 105 Burmese LDTDs between 2008 and 2010. HIV-1 genetic fragments including p17, pol, vif-vpr, vpr-env, and C2V3 were amplified and sequenced. The subtype characterization and HIV-1 transmission were determined by both phylogenetic and phylogeographic analyses. RESULTS: Diverse forms of HIV-1, including subtypes CRF01_AE (41.9%), C (8.6%), B (4.8%), CRF02_AG (1.0%), and inter-subtype recombinants (33.3%), as well as dual infection (10.5%), were detected among the tested LDTDs. Phylogeographic analyses based on pure subtype revealed that 77.8% Burmese LDTDs acquired HIV-1 infection in Yunnan, and the others in Myanmar. Both the C-related and CRF01_AE-related recombinants from these LDTDs appeared to have close genetic relationship with those from IDUs in Myanmar and Dehong. CONCLUSIONS: Burmese LDTDs may contribute to HIV-1 transmission along the China-Myanmar border. The results may provide some new perspective for understanding the on-going generation and prevalence of HIV-1 recombinants in the border region.

[Effects of microstructure of mineralized collagen scaffolds on cell morphology of MG 63].

OBJECTIVE: To evaluate the effects of the microstructure of mineralized collagen scaffolds on cell morphology of MG 63. METHODS: The extrafibrillarly-mineralized collagen (EMC) and intrafibrillarly-mineralized collagen (IMC) scaffolds were fabricated separately by a conventional mineralization approach and a biomimetic, bottom-up mineralization approach. Scanning electron microscopy (SEM) was employed to examine the microstructure of the mineralized collagen scaffolds and cell-scaffold interactions. The effects of the mineralization methods on cell adhesion to the surface of the collagen scaffolds were analyzed by laser scanning microscope (LSM). RESULTS: The two mineralized collagen scaffolds exhibited different microstructures, including the size, morphology and location of the apatites in collagen nanofibers by SEM imaging. In the EMC scaffold, flower-like aggregates randomly deposited around the collagen nanofibers, while no apatite was observed on the surface of the nanofibers. The presence of an intrafibrillar apatite mineral phase in the IMC scaffold was confirmed using energy dispersive X-ray spectroscopy (EDS) coupled to SEM, with the Ca:P ratio of approximately 1.48.This chemical composition was similar to natural bone tissue. The LSM results showed that the IMC scaffold could promote cell spreading compared with the EMC scaffold. Furthermore, the cells cultured on the IMC scaffold (18.54 ± 2.71) showed higher density of vinculin staining than those on the EMC scaffold (14.29 ± 1.32). From the SEM examination, both mineralized collagen scaffolds showed good biocompatibility. However, the cells exhibited different morphology on different scaffolds. CONCLUSION: The microstructure of the mineralized collagen scaffolds can affect the initial cell adhesion and morphology. Furthermore, the IMC scaffold can promote cell adhesion and spreading. The present study will help us to fabricate novel biomimetic materials for alveolar bone regeneration.

Quantitative evaluation of vertical control in orthodontic camouflage treatment for skeletal class II with hyperdivergent facial type.

BACKGROUND: In this study, we sought to quantify the influence of vertical control assisted by a temporary anchorage device (TAD) on orthodontic treatment efficacy for skeletal class II patients with a hyperdivergent facial type and probe into the critical factors of profile improvement. METHODS: A total of 36 adult patients with skeletal class II and a hyperdivergent facial type were included in this retrospective case-control study. To exclude the effect of sagittal anchorage reinforcement, the patients were divided into two groups: a maxillary maximum anchorage (MMA) group (N = 17), in which TADs were only used to help with anterior tooth retraction, and the MMA with vertical control (MMA + VC) group (N = 19), for which TADs were also used to intrude the maxillary molars and incisors. The treatment outcome was evaluated using dental, skeletal, and soft-tissue-related parameters via a cephalometric analysis and cast superimposition. RESULTS: A significant decrease in ANB (P < 0.05 for both groups), the retraction and uprighting of the maxillary and mandibular incisors, and the retraction of protruded upper and lower lips were observed in both groups. Moreover, a significant intrusion of the maxillary molars was observed via the cephalometric analysis (- 1.56 ± 1.52 mm, P < 0.05) and cast superimposition (- 2.25 ± 1.03 mm, P < 0.05) of the MMA + VC group but not the MMA group, which resulted in a remarkable decrease in the mandibular plane angle (- 1.82 ± 1.38°, P < 0.05). The Z angle (15.25 ± 5.30°, P < 0.05) and Chin thickness (- 0.97 ± 0.45°, P < 0.05) also improved dramatically in the MMA + VC group, indicating a better profile and a relaxed mentalis. Multivariate regression showed that the improvement in the soft tissue was closely related to the counterclockwise rotation of the mandible plane (P < 0.05). CONCLUSIONS: TAD-assisted vertical control can achieve intrusion of approximately 2 mm for the upper first molars and induce mandibular counterclockwise rotation of approximately 1.8°. Moreover, it is especially important for patients without sufficient retraction of the upper incisors or a satisfactory chin shape.

Acetylated Sp1 inhibits PTEN expression through binding to PTEN core promoter and recruitment of HDAC1 and promotes cancer cell migration and invasion.

Specificity protein 1 (Sp1) is often overexpressed in cancer cells. Its binding sites are known to exist in the phosphatase and tension homolog deleted on chromosome 10 (PTEN) promoter. In this study, we hypothesized that Sp1 negatively regulates PTEN expression. We used several cell lines to determine the effects of Sp1. The results showed that Sp1 overexpression inhibited the expression and promoter activity of PTEN and correspondingly upregulated AKT phosphorylation, whereas Sp1 knockdown upregulated the expression and promoter ability of PTEN and downregulated AKT phosphorylation. Moreover, a series of deletion and site-directed mutations of the PTEN promoter indicated that Sp1 can inhibit PTEN promoter activity through a specific Sp1-binding site at the PTEN core promoter in vivo. Meanwhile, non-acetylated Sp1, with its loss of DNA binding activity, failed to inhibit the expression and promoter activity of PTEN. Histone deacetylase 1 was necessary for Sp1 to inhibit PTEN expression. The inverse expression of Sp1 and PTEN was found in tongue cancer cells and salivary adenoid cystic cancer (SACC)-LM cells (possessing higher potential for lung metastasis than SACC-83) as compared with that in adjacent normal tissue and SACC-83 cells, respectively. Sp1 knockdown decreased the migration and invasion of SACC-LM cells, whereas Sp1 overexpression increased the migration and invasion of SACC-83 cells. Overall, these results suggest that Sp1 is involved in the development and invasiveness of cancer through inhibition of PTEN.

[Effect of repetitive rapid palatal expansions and constrictions by double hinged expander in maxillary protraction cases].

OBJECTIVE: To investigate the benefits of repetitive rapid palatal expansions/constrictions therapy using double hinged expander over rapid palatal expansion alone with Hyrax expander in maxillary protractions cases and to discuss the indications of the combination therapy. METHODS: Thirty four children with retrognathic maxilla were selected and randomly divided into two treatment groups. Eighteen children were in group A and received maxillary protraction with Hyrax expander rapid palatal expansion alone. Sixteen children were in group B and received maxillary protraction with double hinged expander repetitive rapid palatal expansions/constrictions combin therapy. Cephalometric analysis was done to compare the pre and post-treatment lateral cephalograms. RESULTS: Significant difference in forward movement of maxilla (P<0.05)were observed between group B [A-Np increased 2.53 mm, A-vertical line (A-VRL) increased 2.78 mm] and group A (relatively 1.86 mm and 2.01 mm). Significant difference in soft tissue backward movement of mandible (P<0.05)were also observed between group A (LLC-VRL decreased 2.82 mm) and group B (relatively 1.63 mm). CONCLUSION: Repetitive rapid palatal expansions/constrictions using double hinged expander resulted in more maxilla forward movement compared with Hyrax rapid palatal expansion alone in maxillary protraction cases.

[Three-dimension model analysis for physiological drift of the mandibular dentition after extraction of mandibular second premolars of Angle class II patients].

OBJECTIVE: To observe the self-adjustment of the mandibular dental arch after extraction of the second mandibular premolars. METHODS: Mandibular dental casts of 20 Angle class II patients treated with extraction of lower second premolars and upper first premolars, bonded with Alexander appliance,were taken before (T1) and after self-adjustment (T2). All the casts were laser scanned, Little index, curve of Spee, arch width, arch length and extraction spaces of casts were digitally measured and analyzed with SPSS 16.0. RESULTS: Little index,lower molar width, lower arch length and extraction spaces were reduced [(12.70±3.28) mm vs.(8.82±2.69) mm, P<0.001;(41.21±2.48) mm vs.(40.54±2.23) mm, P<0.001; (24.63±3.19) mm vs.(22.12±2.97) mm, P<0.001;(8.06±0.48) mm vs.(4.17±1.51) mm, P<0.001;(8.13±0.95) mm vs.(4.14±1.98) mm, P<0.001],while the curve of Spee and anterior lower arch length were increased significantly[(2.14±0.75) mm vs.(2.65±0.88) mm, P<0.05; (15.88±2.86) mm vs.(17.55±2.33) mm, P<0.05]. Width between lower canines remained the same[(27.25±2.69) mm vs.(27.26±1.73) mm, P>0 .05]. CONCLUSION: Severe crowding and Angle class II molar relationship could be successfully relived with lower second premolar extraction followed by self-adjustment.

Microbiological Advances in Orthodontics: An Overview and Detailed Analysis of Temporary Anchorage Devices.

Dental biofilm is the initiating factor of oral diseases, such as periodontitis and caries. Orthodontic treatment could alter the microbiome structure balance, and increase the risk of such diseases. Furthermore, fixed appliances can induce temporary changes in the microbiome community, and the changes that clear aligners bring are smaller by comparison. Temporary anchorage devices (TADs) are skeletal anchorages that are widely used in orthodontic treatment. Microorganisms affect the occurrence and development of inflammation surrounding TADs. At present, existing researches have verified the existence of plaque biofilm on the surface of TADs, but the formation of plaque biofilm and plaque composition under different stable conditions have not been fully understood. The development of high-throughput sequencing, molecular biology experiments, and metabonomics have provided new research ideas to solve this problem. They can become an effective means to explore the microbiome surrounding TADs.

Stem Cells From Human Exfoliated Deciduous Teeth Alleviate Liver Cirrhosis via Inhibition of Gasdermin D-Executed Hepatocyte Pyroptosis.

Liver cirrhosis represents a type of end-stage liver disease with few effective therapies, which was characterized by damaged functional liver tissue due to long-term inflammation. Gasdermin D (GSDMD)-executed programmed necrosis is reported to be involved in inflammation. However, the role of GSDMD in liver cirrhosis remains unclear. In this study, we used a CCl4-induced cirrhosis model and found stem cells from human exfoliated deciduous teeth (SHED) infusion showed profound therapeutic effects for liver cirrhosis. Mechanistically, NLRP3 inflammasome-activated GSDMD and its pyroptosis were upregulated in liver cirrhosis, while SHED infusion could suppress the expression of GSDMD and Caspase-1, resulting in reduced hepatocyte pyroptosis and inflammatory cytokine IL-1ß release. Consistently, SHED could inhibit the elevated expression of NLRP3, GSDMD and Caspase-1 induced by CCl4 treatment in vitro co-culture system, which was mediated by decreasing reactive oxygen species (ROS) generation. Moreover, the pyroptosis inhibitor disulfiram showed similar therapeutic effects for liver cirrhosis as SHED. In conclusion, SHED alleviates CCl4-induced liver cirrhosis via inhibition of hepatocytes pyroptosis. Our findings could provide a potential treatment strategy and novel target for liver cirrhosis.

Mechanical force-promoted osteoclastic differentiation via periodontal ligament stem cell exosomal protein ANXA3.

Exosomes play a critical role in intracellular communication. The biogenesis and function of exosomes are regulated by multiple biochemical factors. In the present study, we find that mechanical force promotes the biogenesis of exosomes derived from periodontal ligament stem cells (PDLSCs) and alters the exosomal proteome profile to induce osteoclastic differentiation. Mechanistically, mechanical force increases the level of exosomal proteins, especially annexin A3 (ANXA3), which facilitates exosome internalization to activate extracellular signal-regulated kinase (ERK), thus inducing osteoclast differentiation. Moreover, the infusion of exosomes derived from PDLSCs into mice promotes mechanical force-induced tooth movement and increases osteoclasts in the periodontal ligament. Collectively, this study demonstrates that mechanical force treatment promotes the biogenesis of exosomes from PDLSCs and increases exosomal protein ANXA3 to facilitate exosome internalization, which activates ERK phosphorylation, thus inducing osteoclast differentiation. Our findings shed light on new mechanisms for how mechanical force regulates the biology of exosomes and bone metabolism.

A New HIV-1 K28E32-Reverse Transcriptase Variant Associated with the Rapid Expansion of CRF07_BC among Men Who Have Sex with Men.

HIV-1 CRF07_BC originated among injection drug users (IDUs) in China. After diffusing into men who have sex with men (MSM), CRF07_BC has shown a rapid expansion in this group; however, the mechanism remains unclear. Here, we identified a new K28E32 variant of CRF07_BC that was characterized by five specific mutations (E28K, K32E, E248V, K249Q, and T338S) in reverse transcriptase. This variant was mainly prevalent among MSM, and was overrepresented in transmission clusters, suggesting that it could have driven the rapid expansion of CRF07_BC in MSM, though founder effects cannot be ruled out. It was descended from an evolutionary intermediate accumulating four specific mutations and formed an independent phylogenetic node with an estimated origin time in 2003. The K28E32 variant was demonstrated to have significantly higher in vitro HIV-1 replication ability than the wild type. Mutations E28K and K32E play a critical role in the improvement of in vitro HIV-1 replication ability, reflected by improved reverse transcription activity. The results could allow public health officials to use this marker (especially E28K and K32E mutations in the reverse transcriptase (RT) coding region) to target prevention measures prioritizing MSM population and persons infected with this variant for test and treat initiatives. IMPORTANCE HIV-1 has very high mutation rate that is correlated with the survival and adaption of the virus. The variants with higher transmissibility may be more selective advantage than the strains with higher virulence. Several HIV-1 variants were previously demonstrated to be correlated with higher viral load and lower CD4 T cell count. Here, we first identified a new variant (the K28E32 variant) of HIV-1 CRF07_BC, described its origin and evolutionary dynamics, and demonstrated its higher in vitro HIV-1 replication ability than the wild type. We demonstrated that five RT mutations (especially E28K and K32E) significantly improve in vitro HIV-1 replication ability. The appearance of the new K28E32 variant was associated with the rapidly increasing prevalence of CRF07_BC among MSM.

An Overview of Anterior Repositioning Splint Therapy for Disc Displacement-related Temporomandibular Disorders.

Anterior repositioning splint (ARS) therapy is considered one of the most effective therapies for treating disc displacement-related temporomandibular disorders (TMDs), which account for a large proportion of TMD cases. Owing to the wide application of this therapy, the exact mechanism of remission has increasingly drawn attention. Given that practitioners have different views on ARS therapy, its indications are broadened, and operating methods diverged. This review attempts to provide an overview of ARS therapy and helps practitioners establish indications and suitable operating methods. Representative views in the past 10 years were summarised, and conclusions were drawn as follows: The mechanism of ARS therapy is mainly attributed to internal derangement correction, improvement of stress distribution and recently reported joint remodeling. It has an evident effect in the short term, and the most prevalent operating methods are protruding the mandible to the edge-to-edge position and wearing the ARS for 24 hours daily for 3-6 months. However, long-term stability is not optimal, and thus indications should be selected carefully. Notably, most of the clinical studies in this field are case analyses with low-quality evidence. Well-designed RCTs are required to further validate relevant theories.

Genetic Characteristics of Three Unique Recombinant Forms of HIV-1 in Yunnan, China.

To explore the molecular epidemiological status of human immunodeficiency virus type 1 (HIV-1) in Yunnan, China, three HIV-1 near full-length genomes were amplified and sequenced from plasma samples that were collected from Burmese patients newly diagnosed with HIV-1 in Dehong Prefecture in Yunnan Province in 2017. Phylogenetic and bootscanning analyses revealed that all the sequences might be HIV-1 second-generation recombinant forms of circulating recombinant forms (CRF07_BC and CRF83_cpx) and unique recombinant forms. One of the sequences contained six CRF01_AE fragments, five subtype C fragments, and two subtype B fragments, which were separated by 12 breakpoints. These results revealed that the second-generation recombination of HIV-1 within different strains is still ongoing in Dehong, China. Systematic surveys and immediate interventions are urgently needed to prevent the formation of increasingly complex HIV-1 recombinant forms.