Regulation of metal homoeostasis by two F-group bZIP transcription factors bZIP48 and bZIP50 in rice

Zinc (Zn) deficiency not only impairs plant growth and development but also has negative effects on human health. Rice (Oryza Sativa L.) is a staple food for over half of the global population, yet the regulation of Zn deficiency response in rice remains largely unknown. In this study, we provide evidence that two F-group bZIP transcription factors, OsbZIP48/50, play a crucial role in Zn deficiency response. Mutations in OsbZIP48/50 result in impaired growth and reduced Zn/Fe/Cu content under Zn deficiency conditions. The N-terminus of OsbZIP48/OsbZIP50 contains two Zn sensor motifs (ZSMs), deletion or mutation of these ZSMs leads to increased nuclear localization. Both OsbZIP48 and OsbZIP50 exhibit transcriptional activation activity, and the upregulation of 1117 genes involved in metal uptake and other processes by Zn deficiency is diminished in the OsbZIP48/50 double mutant. Both OsbZIP48 and OsbZIP50 bind to the promoter of OsZIP10 and activate the ZDRE cis-element. Amino acid substitution mutation of the ZSM domain of OsbZIP48 in OsbZIP50 mutant background increases the content of Zn/Fe/Cu in brown rice seeds and leaves. Therefore, this study demonstrates that OsbZIP48/50 play a crucial role in regulating metal homoeostasis and identifies their downstream genes involved in the Zn deficiency response in rice.

Diurnal regulation of alternative splicing associated with thermotolerance in rice by two glycine-rich RNA-binding proteins

Rice (Oryza sativa L.) production is threatened by global warming associated with extreme high temperatures, and rice heat sensitivity is differed when stress occurs between daytime and nighttime. However, the underlying molecular mechanism are largely unknown. We show here that two glycine-rich RNA binding proteins, OsGRP3 and OsGRP162, are required for thermotolerance in rice, especially at nighttime. The rhythmic expression of OsGRP3/OsGRP162 peaks at midnight, and at these coincident times, is increased by heat stress. This is largely dependent on the evening complex component OsELF3-2. We next found that the double mutant of OsGRP3/OsGRP162 is strikingly more sensitive to heat stress in terms of survival rate and seed setting rate when comparing to the wild-type plants. Interestingly, the defect in thermotolerance is more evident when heat stress occurred in nighttime than that in daytime. Upon heat stress, the double mutant of OsGRP3/OsGRP162 displays globally reduced expression of heat-stress responsive genes, and increases of mRNA alternative splicing dominated by exon-skipping. This study thus reveals the important role of OsGRP3/OsGRP162 in thermotolerance in rice, and unravels the mechanism on how OsGRP3/OsGRP162 regulate thermotolerance in a diurnal manner.

The hot science in rice research: How rice plants cope with heat stress

Global climate change has great impacts on plant growth and development, reducing crop productivity worldwide. Rice (Oryza sativa L.), one of the world's most important food crops, is susceptible to high-temperature stress from seedling stage to reproductive stage. In this review, we summarize recent advances in understanding the molecular mechanisms underlying heat stress responses in rice, including heat sensing and signalling, transcriptional regulation, transcript processing, protein translation, and post-translational regulation. We also highlight the irreversible effects of high temperature on reproduction and grain quality in rice. Finally, we discuss challenges and opportunities for future research on heat stress responses in rice.

Deep learning-based prediction of mandibular growth trend in children with anterior crossbite using cephalometric radiographs

BACKGROUND

It is difficult for orthodontists to accurately predict the growth trend of the mandible in children with anterior crossbite. This study aims to develop a deep learning model to automatically predict the mandibular growth result into normal or overdeveloped using cephalometric radiographs.

METHODS

A deep convolutional neural network (CNN) model was constructed based on the algorithm ResNet50 and trained on the basis of 256 cephalometric radiographs. The prediction behavior of the model was tested on 40 cephalograms and visualized by equipped with Grad-CAM. The prediction performance of the CNN model was compared with that of three junior orthodontists.

RESULTS

The deep-learning model showed a good prediction accuracy about 85%, much higher when compared with the 54.2% of the junior orthodontists. The sensitivity and specificity of the model was 0.95 and 0.75 respectively, higher than that of the junior orthodontists (0.62 and 0.47 respectively). The area under the curve value of the deep-learning model was 0.9775. Visual inspection showed that the model mainly focused on the characteristics of special regions including chin, lower edge of the mandible, incisor teeth, airway and condyle to conduct the prediction.

CONCLUSIONS

The deep-learning CNN model could predict the growth trend of the mandible in anterior crossbite children with relatively high accuracy using cephalometric images. The deep learning model made the prediction decision mainly by identifying the characteristics of the regions of chin, lower edge of the mandible, incisor teeth area, airway and condyle in cephalometric images.

An ABA-serotonin module regulates root suberization and salinity tolerance

Suberin in roots acts as a physical barrier preventing water/mineral losses. In Arabidopsis, root suberization is regulated by abscisic acid (ABA) and ethylene in response to nutrient stresses. ABA also mediates coordination between microbiota and root endodermis in mineral nutrient homeostasis. However, it is not known whether this regulatory system is common to plants in general, and whether there are other key molecule(s) involved. We show that serotonin acts downstream of ABA in regulating suberization in rice and Arabidopsis and negatively regulates suberization in rice roots in response to salinity. We show that ABA represses transcription of the key gene (OsT5H) in serotonin biosynthesis, thus promoting root suberization in rice. Conversely, overexpression of OsT5H or supplementation with exogenous serotonin represses suberization and reduces tolerance to salt stress. These results identify an ABA-serotonin regulatory module controlling root suberization in rice and Arabidopsis, which is likely to represent a general mechanism as ABA and serotonin are ubiquitous in plants. These findings are of significant importance to breeding novel crop varieties that are resilient to abiotic stresses and developing strategies for production of suberin-rich roots to sequestrate more CO₂ , helping to mitigate the effects of climate change.

bZIP17 regulates heat stress tolerance at reproductive stage in Arabidopsis

High temperature elicits a well-conserved response called the unfolded protein response (UPR) to bring protein homeostasis in the endoplasmic reticulum (ER). Two key UPR regulators bZIP28 and bZIP60 have been shown to be essential for maintaining fertility under heat stress conditions in Arabidopsis, however, the function of transcriptional activator bZIP17, a paralog of bZIP28, in heat stress response at reproductive stage is not reported. Here we found that bzip17 mutant plants were sensitive to heat stress in terms of silique length and fertility comparing to that of wildtype (WT) Arabidopsis plants, and transcriptomic analysis showed that 1380 genes were specifically up-regulated and 493 genes were specifically down-regulated by heat stress in the flowers of WT plants comparing to that in bzip17 mutant plants. These bZIP17-dependent up-regulated genes were enriched in responses to abiotic stresses such as water deprivation and salt stress. Further chromatin immuno-precipitation coupled with high-throughput sequencing (ChIP-Seq) uncovered 1645 genes that were direct targets of bZIP17 in MYC-bZIP17 expressing seedlings subjected to heat stress. Among these 1645 genes, ERSE-II cis-element was enriched in the binding peaks of their promoters, and the up-regulation of 113 genes by heat stress in flowers was dependent on bZIP17. Our results revealed direct targets of bZIP17 in flowers during heat stress responses and demonstrated the important role of bZIP17 in maintaining fertility upon heat stress in plants.

Supplementary Information

The online version contains supplementary material available at 10.1007/s42994-021-00062-1.

Roles of plant hormones in thermomorphogenesis

Global warming has great impacts on plant growth and development, as well as ecological distribution. Plants constantly perceive environmental temperatures and adjust their growth and development programs accordingly to cope with the environment under non-lethal warm temperature conditions. Plant hormones are endogenous bioactive chemicals that play central roles in plant growth, developmental, and responses to biotic and abiotic stresses. In this review, we summarize the important roles of plant hormones, including auxin, brassinosteroids (BRs), Gibberellins (GAs), ethylene (ET), and jasmonates (JAs), in regulating plant growth under warm temperature conditions. This provides a picture on how plants sense and transduce the warm temperature signals to regulate downstream gene expression for controlling plant growth under warm temperature conditions via hormone biosynthesis and signaling pathways.

China experts' consensus on preventive and interceptive orthodontic treatments of malocclusions of children

Malocclusion is one of the three most common oral diseases reported by World Health Organization(WHO). In China, its incidence rate is rising. Malocclusion seriously affects the dental and maxillofacial function, facial appearance and growth development of nearly 260 million children in China, and what is more, it affects their physical and mental health development. Malocclusion occurrence is related to genetic and environmental factors. Early treatment of malocclusion can create a good dental and maxillofacial development environment, correct abnormal growth and control the adverse effects of abnormal genetic factors. It can effectively reduce the prevalence of children's malocclusion and enhance their physical and mental health. This is an urgent need from the economic perspective of our society, so it has great practical and social significance. Experts from the project group "standard diagnose and treatment protocols for early orthodontic intervention of malocclusions of children" which initiated by China National Health Institute of Hospital Administration wrote the "China Experts' Consensus on Preventive and Interceptive Orthodontic Treatments of Malocclusions of Children", which aims to guide and popularize the clinical practice, improve the clinical theory and practice level, and accelerate the disciplinary development of early treatment of children's malocclusion in China. The consensus elaborates the harmfulness of malocclusion and the necessity of early treatment, and brings up the principles and fundamental contents. Based on the law of dental and maxillofacial development, this paper puts forward the guiding suggestions of preventive and interceptive treatments in different stages of dental development ranging from fetus to early permanent dentition. It is a systematic project to promote and standardize the early treatment of malocclusion. Through scientific and comprehensive stratified clinical practice and professional training, the clinical system of early treatment of malocclusion in China will eventually be perfected, so as to comprehensively care for children's dental and maxillofacial health, and improve their oral and physical health in China.

Comparison of tooth movement and biological response resulting from different force magnitudes combined with osteoperforation in rabbits

OBJECTIVE

To compare tooth movement rate and histological responses with three different force magnitude designs under osteoperforation in rabbit models.

METHODOLOGY

48 rabbits were divided into three groups: Group A, Group B, and Group C, with traction force of 50 g, 100 g, 150 g, respectively. Osteoperforation was performed at the mesial of the right mandibular first premolar, the left side was not affected. One mini-screw was inserted into bones between two central incisors. Coil springs were fixed to the first premolars and the mini-screw. Tooth movement distance was calculated, and immunohistochemical staining of PCNA, OCN, VEGF, and TGF-β1 was analyzed.

RESULTS

The tooth movement distance on the surgical side was larger than the control side in all groups (P<0.01). No significant intergroup difference was observed for the surgical side in tooth movement distance among the three groups (P>0.05). For the control side, tooth movement distance in Group A was significantly smaller than Groups B and C (P<0.001); no significant difference in tooth movement distance between Group B and Group C was observed (P>0.05). On the tension area of the moving premolar, labeling of PCNA, OCN, VEGF and TGF-β1 were confirmed in alveolar bone and periodontal ligament in all groups. PCNA, OCN, VEGF and TGF-β1 on the surgical side was larger than the control side in all groups (P<0.001).

CONCLUSION

Osteoperforation could accelerate orthodontic tooth movement rate in rabbits. Fast osteoperforation-assisted tooth movement in rabbits was achieve with light 50 g traction.

Comparison of the effects of rapid maxillary expansion versus Twin Block appliance on mandibular growth in skeletal Class II patients

Background

This is a retrospective study that compares mandibular growth changes in skeletal Class II patients treated by rapid maxillary expansion (RME) and following fixed appliance with those patients treated by Twin-Block (TB) and following fixed appliance.

Methods

Fourteen patients treated by RME and following fixed appliance were included into the RME group. Fifteen patients treated by Twin-Block and following fixed appliance were included into the TB group. Lateral cephalometric radiographs taken before treatment and immediately after fixed appliance treatment were used to evaluate mandibular growth effects.

Results

The starting forms of the patients in the two groups were examined to be of good comparability. The mandibular length increased significantly in both groups as measured by Co-Gn, Go-Gn and Ar-Gn, but the TB group didn’t show more mandibular growth than the RME group (P > 0.05). Skeletal changes of the mandible in vertical dimension were different in the two groups. The change in FMA was 0.35° in the RME group, while the change was 2.65° in the TB group (P < 0.001). The change in LAFH was 5.14 mm in the RME group, significantly smaller than the change of 10.19 mm in the TB group (P < 0.001).

Conclusion

The investigated Phase I treatment with RME followed by Phase II treatment of fixed appliance achieved the same increases in sagittal mandibular growth and facial profile improvements as the Twin-Block therapy. The treatment with RME followed by fixed appliance was better for vertical control, while the treatment with Twin-Block followed by fixed appliance significantly increased the mandibular plane angle.

[Advances in research of microRNA in the growth and development of mandibular condyle cartilage]

MicroRNA (miRNA) are a class of small non-coding single-stranded RNA that exert their biological effects by binding to target messenger RNA (mRNA). There is new evidence that miRNA may play an important role in regulating the growth and development of mandibular condylar cartilage. In this paper, the production and mechanism of miRNA are reviewed, and the progress of studies on the growth and development of mandibular condylar cartilage, which is helpful to further study the growth and development of mandibular condylar cartilage.

[Advance and review: miniscrew-assisted rapid palatal expansion]

Rapid palatal expansion (RPE) is commonly used to correct transverse maxillary deficiencies and recognized as a reliable orthopedic procedure in children and adolescents. For adults, however, conventional RPE has been considered rarely successful and can produce undesirable dental effects. Along with the development of digital techniques and mini-implant anchorage, a novel method called miniscrew-assisted RPE (MARPE) has become available for the treatment of maxillary transverse deficiency in older patients recently. In this article, the biomechanical principles and indications of MARPE, the advances in device design, the clinical effects, the matters needing attention and limitations of this method, and the stability after expansion are discussed.

Evaluation of the long-term stability of micro-screws under different loading protocols: a systematic review

The aim of this systematic review was to investigate the association between the different factors of loading protocols and the long-term stability of micro-screws from biomechanical and histological viewpoints. Searches were performed on PubMed, Embase, Cochrane Library, Wanfang and CNKI databases for animal experiments comparing loading protocols and the long-term stability of micro-screws. Among 1011 detected papers, 16 studies met the eligibility criteria and were selected for analysis. Most studies showed medium methodological quality for evaluation of micro-screws' long-term stability. Five studies reported that loading would not destroy the long-term stability of micro-screws. Three studies indicated that low-intensity immediate loading or a 3-week minimal healing time was acceptable. Two studies reported that the loading magnitude was a controversial issue with regard to the micro-screws' long-term stability. Two studies suggested that counterclockwise loading could decrease the long-term stability of micro-screws. In conclusion, immediate loading below 100g force, healing time greater than 3 weeks, regular loading below 200g force and a clockwise direction of force supported the long-term stability of micro-screws. Further studies relating to the combination of varying loading conditions will be needed.

[Streptococcal toxic shock syndrome caused by Streptococcus pyogenes: a retrospective study of 15 pediatric cases]

Objective: To improve the understanding of clinical characteristics of streptococcal toxic shock syndrome (STSS) caused by Streptococcus pyogenes (S. pyogenes) in children. Methods: A retrospective study was conducted to analyze the clinical data of STSS caused by S. pyogenes (culture-confirmed) in 7 tertiary hospitals during 2010-2017 in China. Clinical and laboratory data were collected by reviewing the medical records. Results: Fifteen cases of STSS, including 9 males, were confirmed and the ages of the patients ranged from 6 months to 15 years, with median age of 3 years. All cases had the positive blood culture for S. pyogenes and only 3 cases had short course of β-lactam treatment before blood culture. Medical evaluation was initiated within (5.1±4.6) days after symptom onset. All patients had fever, and 13 patients had multiple organ dysfunction and 10 patients had disseminated intravascular coagulationl (DIC). Twelve cases had severe pneumonia with or without skin and (or) soft tissue infections. Underlying conditions included giant hemangioma of the skin in 2 patients and varicella in 1 patient. All isolated strains in 14 cases were sensitive to penicillin G, ceftriaxone/cefotaxime, vancomycin, but 12 and 13 isolates were resistant to clindamycin and erythromycin, respectively. Eight patients died, and 5 of them died within 24 hours after admission. One patient was lost to follow-up after intended discharge against medical advice. Conclusion: STSS caused by S. pyogenes in children is a severe syndrome with rapid clinical progression and high mortality rate, and thus the pediatricians should be aware of STSS and immediately initiate aggressive treatment for the suspected cases.

Resistance of rice to insect pests mediated by suppression of serotonin biosynthesis

Rice is one of the world's most important foods, but its production suffers from insect pests, causing losses of billions of dollars, and extensive use of environmentally damaging pesticides for their control^1,2. However, the molecular mechanisms of insect resistance remain elusive. Although a few resistance genes for planthopper have been cloned, no rice germplasm is resistant to stem borers. Here, we report that biosynthesis of serotonin, a neurotransmitter in mammals³, is induced by insect infestation in rice, and its suppression confers resistance to planthoppers and stem borers, the two most destructive pests of rice². Serotonin and salicylic acid derive from chorismate⁴. In rice, the cytochrome P450 gene CYP71A1 encodes tryptamine 5-hydroxylase, which catalyses conversion of tryptamine to serotonin⁵. In susceptible wild-type rice, planthopper feeding induces biosynthesis of serotonin and salicylic acid, whereas in mutants with an inactivated CYP71A1 gene, no serotonin is produced, salicylic acid levels are higher and plants are more insect resistant. The addition of serotonin to the resistant rice mutant and other brown planthopper-resistant genotypes results in a loss of insect resistance. Similarly, serotonin supplementation in artificial diet enhances the performance of both insects. These insights demonstrate that regulation of serotonin biosynthesis plays an important role in defence, and may prove valuable for breeding insect-resistant cultivars of rice and other cereal crops.

Use of magnetic biochars for the immobilization of heavy metals in a multi-contaminated soil

Modified biochars, including magnetic biochars, have been tested in water for the removal of inorganic pollutants. However, at present it is unknown if they possess benefits over conventional biochar materials in relation to land remediation. A paddy soil was collected near Liantang village in Lechang Pb-Zn mine area in Guangdong Province (China). The soil was polluted with Cd, Cu, Zn and Pb, with total contents of 1.4mg/kg, 80mg/kg, 1638mg/kg and 2463mg/kg, respectively. We prepared magnetic and conventional biochar from two feedstocks (poultry litter and Eucalyptus) at a temperature of 300 and 500°C. A sequential extraction procedure for the speciation of heavy metals and a phytotoxicity test using rice were performed. Acid-soluble Cd in soils amended with PLB was 8 to 10% lower than in the control polluted soil. This figure was 27 to 29% for acid-soluble Zn and 59 to 63% for acid-soluble Cu. In some cases, differences were found between the heavy metal fractionation in samples amended with magnetic and conventional biochars. Plant biomass was unaffected by most treatments, but increased by 32% in the treatments containing magnetic poultry litter biochar. Our study shows that a careful choice of feedstock is of utmost importance for successful containment of heavy metals in a multi-contaminated mining area soil. An appropriate choice of feedstock (in the case of this study poultry litter vs. eucalyptus) was more determinant with respect to the mobility of pollutants than altering pyrolysis temperature or modifying surface properties through magnetization. However, surface modification through magnetization can have a significant impact on plant yield and offer comparative advantages in the management of some degraded landscapes.

[Effects of Oridonin combined with Capecitabine on the proliferaction of MDA-MB-231 human breast cancer cells]

Objective: To investigate the effects of oridonin combined with capecitabine on the proliferaction of MDA-MB-231 human breast cancer cells. Methods: Effect of different concentrations(10, 20 and 40 μmol/L)of oridonin, capecitabine and their combination on the proliferation of MDA-MB-231 cells after incubation for 24 or 48 h was studied. Then, the effect of 5 μmol/L of oridonin, capecitabine and their combination on cell colony formation was detected. Finally, influence of 20 μmol/L of oridonin, capecitabine and their combination on morphological alteration of nucleus, cell cycle and apoptosis was explored. Results: The inhibition rate on MDA-MB-231 cells after incubation with 20 μmol/L oridonin or capecitabine for 48 h was 49.5% and 58.6%, respectively, while the inhibition rate against proliferation of MDA-MB-231 cells reached 94.6% with combination of 20 μmol/L oridonin and capecitabine. Cells incubated with combination of oridonin and capecitabine formed fewer and smaller colonies (P<0.01). Meanwhile, cells in the combination group arrested at S and G2/M phases at the same time, and combination of two drugs caused more apoptotic cells (P<0.01). Conclusion: Oridonin combined with capecitabine can synergistically inhibit the proliferation of MDA-MB-231 human breast cancer cells.

[Impact of anchorage implant design factors on its primary stability]

During the past decade, the anchorage implants have been widely used in the orthodontic treatment. Many scholars have studied the influence of different factors on anchorage implant's primary stability, including anchorage implant's material properties, structural design, surgical procedure, bone condition, loading force's magnitude and direction. This article is to review the influence of anchorage implant's shape, dimension, neck design and thread design on its primary stability.

[An analysis of 181 cases with blood stream infection caused by Streptococcus agalactiae in children from 2011 to 2015: a multi-center retrospective study]

OBJECTIVE

To analyze the clinical characteristics of blood stream infection caused by Streptococcus agalactiae in children and the drug-resistance of the isolates.

METHOD

All cases with Streptococcus agalactiae growth in blood or cerebrospinal fluid cultures from January 1, 2011 to December 31, 2015 were enrolled by checking the laboratory information system (LIS) from 7 Class 3 Grade A hospitals (4 in Zhejiang, 2 in Shanghai and 1 in Chongqing). Clinical data were collected for analysis. χ(2) test, t test and non parametric test were used in the study.

RESULT

One hundred and eighty-one pediatric cases of blood stream infection caused by Streptococcus agalactiae were included in current study. Eighty-six cases (47.5%) were male, and with age range from one day to 9 years (media 13 days). Thirty cases (16.6%) were premature infants and 127 cases (70.2%) were born via vaginal delivery. Seventy-one cases (39.2%) had early onset (<7 d) infections, and 106 cases (58.6%) had late onset (7-89 d) infections. Seventy-eight cases (43.1%) were complicated with purulent meningitis. Incidences of vaginal delivery(81.7%(58/71) vs. 62.3%(66/106)), shortness of breath moaning (43.7%(31/71) vs. 15.1%(16/106)) and preterm premature rupture of membranes (25.4%(18/71) vs. 3.8%(4/106)) were higher in the early onset infection group compared with the late onset group(P all<0.05). However, the number of cases who had fever(25.4%(18/71)vs.85.8%(91/106)) and complicated with purulent meningitis (29.6%(21/71) vs. 53.8%(57/106)) in early onset infections group was less than that in the late onset group(P both<0.05). The blood cultures of most patients (87.8%) were performed before the use of antibiotics. Drug-resistant tests showed that the sensitive rates to penicillin G, ceftriaxone and cefotaxime were 98.9%, 99.0% and 99.0% respectively. All strains were sensitive to vancomucine. The rates of resistance to clindamycin and erythromycin were 68.0% and 34.0%, respectively. Only 39 cases (22.0%) were treated with single antibiotics of either penicillins or cephalosporins, 80 cases (45.2%) were treated with antibiotics containing β lactamase inhibitor, 61 cases (34.5%) were treated with either meropenem or cefoperazone-sulbactam. One hundred and fifty-four cases were cured, while 19 died (including 13 complicated with purulent meningitis) and 8 lost to follow up after giving up of treatment.

CONCLUSION

The incidence and mortality of blood stream infection caused by Streptococcus agalactiae complicated with purulent meningitis are high in children. Penicillin is the first choice in treatment. Antibiotics should be selected accorrding to the drug-resistance test.

Involvement of the MAPK pathway in the pressure-induced synovial metaplasia procedure for the temporomandibular joint

Abnormal pressure is an important factor that contributes to bone adaptation in the temporomandibular joint (TMJ). We determined the effect of the mitogen-activated protein kinases (MAPK) pathway on the pressure-induced synovial metaplasia procedure for the TMJ, both in vitro and in vivo. Synovial fibroblasts (SFs) were exacted from rat TMJs and exposed to different hydrostatic pressures. The protein extracts were analyzed to determine the activation of ERK1/2, JNK, and p38. Surgical anterior disc displacement (ADD) was also performed on Japanese rabbits, and the proteins of TMJ were isolated to analyze pressure-induced MAPK activation after 1, 2, 4, and 8 weeks. The results showed that the activation of ERK1/2 and JNK in SFs significantly changed with increasing hydrostatic pressure, whereas p38 activation did not change. Moreover, p38 was activated in animals 1 week after surgical ADD. The levels of p38 gradually increased after 2 and 4 weeks, and then slightly decreased but remained higher than in the control 8 weeks after surgical ADD. Nevertheless, JNK was rarely activated after the ADD treatment. Our findings suggest the involvement of MAPK activation in the pressure-induced synovial metaplasia procedure with pressure loading in TMJ.

[Condylar morphological changes before and after orthodontic treatment for angle Class I malocclusion adult patients]

PURPOSE

To evaluate the condylar morphological changes in adult Angle Class I malocclusionpatients before and after orthodontic treatment using a cone-beam CT (CBCT).

METHODS

Images of 25 adult Angle Class I patients (5 males, 20 females) who had no temporomandibular joint disorder symptom were involved in this study, and Mimics 10.01 software was used to reconstruct the three-dimensional condyle and measure the height of condyle, the area and bone density of the largest cross sectional plane and sagittal plane, and the volume and bone density of the whole and upper three-dimensional condyle before and after orthodontic treatment. Paired t test was used for comparison between pre- and post-treatment condylar metric analysis with SPSS 19.0 software package.

RESULTS

After treatment, the area and bone density of the largest cross sectional plane and sagittal plane were reduced significantly(P<0.05). The volume and bone density of the whole three-dimensional condyle and bone density of the upper three-dimensional condyle were reduced significantly(P<0.05).

CONCLUSIONS

Adaptive bone remodeling of the condyle may occur due to alternation of occlusion by orthodontic treatment in adult Angle Class I malocclusion patients.

Characterization of htAKR, a novel gene product in the aldo-keto reductase family specifically expressed in human testis

In human testis, expression of a novel member of the aldo-keto reductase family was identified. Based on its testis-specific expression, we termed this protein human testis aldo-keto reductase (htAKR). In addition to four major isoforms, the existence of multiple alternatively spliced products of htAKR was detected using RT-PCR followed by nested PCR. htAKR was a homologue of mouse liver keto-reductase, AKR1E1, with close similarity in their genomic organizations. htAKR4, the longest isoform, was expressed as a non-fused native form. It exhibited a limited activity toward 9,10-phenanthrenequinone, while no activity toward the steroids or prostaglandins was demonstrated. Using the laser capture microdissection technique and RT-PCR, expression of htAKR was detected in testicular germ cells as well as in interstitial cells. The levels of htAKR mRNA in the tissues obtained from seminoma were much lower than those in normal testes. A significant decline in the htAKR expression was observed when NEC8, a cell line originated from a human testicular germ cell tumour, was exposed to phorbol 12-myristate 13-acetate or 5alpha-dihydrotestosterone. These results indicate that the expression of htAKR, down-regulated in the testicular tumour, is possibly controlled by mitogenic and hormonal signals.

Motoneuron-specific expression of NR3B, a novel NMDA-type glutamate receptor subunit that works in a dominant-negative manner

We have identified a novel glutamate receptor subunit on the human and mouse genome. Cloning of the mouse cDNA revealed a protein consisting of 1003 amino acids encoded by at least nine exons. This protein showed the highest similarity (51%) to the NR3A subunit of the NMDA receptor and therefore was termed NR3B. NR3B has a structure typical of glutamate receptor family members with a signal peptide and four membrane-associated regions. Amino acids forming a ligand-binding pocket are conserved. When coexpressed with NR1 and NR2A in heterologous cells, NR3B suppressed glutamate-induced current similarly to NR3A. Thus members of the NR3 class of NMDA receptors act as dominant-negative subunits in the NMDA receptor complex. NR3B shows very restricted expression in somatic motoneurons of the brainstem and spinal cord. Its expression in other types of motoneurons, including autonomic motoneurons in Onuf's nucleus and oculomotor neurons, is significantly weaker. Our results indicate that NR3B is important as a regulatory subunit that controls NMDA receptor transmission in motoneurons. It may be involved in the pathogenesis of neurodegenerative diseases involving motoneurons as well.

Cloning and characterization of LUN, a novel ring finger protein that is highly expressed in lung and specifically binds to a palindromic sequence

We isolated cDNAs encoding a novel RING finger protein (LUN), the mRNAs of which were expressed at high levels in the lung. In situ hybridization revealed that LUN mRNAs were expressed in the alveolar epithelium of the lung. The LUN gene locus was assigned to chromosome 9p21, which contains candidate tumor suppressor genes associated with loss of heterozygosity in more than 86% of small cell lung cancers. We clarified that LUN is localized to the nucleus and reveals Zn(2+)-dependent DNA binding activity. The region from amino acids 51 to 374 of LUN is responsible for DNA binding. Furthermore, we identified a novel palindromic binding consensus (5'-TCCCAGCACTTTGGGA-3') for the LUN binding. Interestingly, this LUN binding palindromic sequence is found in the upstream transcriptional regulatory region of the E-cadherin gene and two intervening regions of the talin gene. Our results suggested that LUN might be an important trans-acting transcriptional regulator for lung cancer-associated genes including E-cadherin and talin genes.

[Mechanism of sini decoction in regulating beta-adrenergic receptor signal transduction in rats with myocardial ischemia]

OBJECTIVE

To investigate the effect of Sini Decoction (SND) on beta-adrenergic receptor (beta-AR) signal transduction in rats with myocardial ischemia.

METHODS

After beta-AR had been blocked by propranolol, the myocardial ischemia rats were established by pituitrin injection. The density of beta-AR in myocardial cell membrane was determined by radioligand binding assay, cAMP level in plasma and myocardial tissue was detected by radioimmunoassay (RIA), and the mRNA expression of beta 1-AR and beta 1-AR kinase (beta ARK-1) was measured by quantitative reverse transcriptase polymerase chain reaction (RT-PCR) amplifying assay.

RESULTS

In myocardial ischemia group, the density of beta 1-AR was up-regulated and the mRNA expression of beta ARK-1 increased (P < 0.01), but the cAMP level in plasma and myocardium was lower than that in the normal group (P < 0.01 and P < 0.05). SND could promote beta 1-AR mRNA expression and inhibit beta ARK-1 mRNA expression so as to increase the density of beta-AR and cause significant raising of cAMP level in plasma and myocardium.

CONCLUSION

SND could reduce the desensitization of beta 1-AR during myocardial ischemia and improve signal transduction of beta-AR.

Single-molecule enzymatic dynamics

Enzymatic turnovers of single cholesterol oxidase molecules were observed in real time by monitoring the emission from the enzyme's fluorescent active site, flavin adenine dinucleotide (FAD). Statistical analyses of single-molecule trajectories revealed a significant and slow fluctuation in the rate of cholesterol oxidation by FAD. The static disorder and dynamic disorder of reaction rates, which are essentially indistinguishable in ensemble-averaged experiments, were determined separately by the real-time single-molecule approach. A molecular memory phenomenon, in which an enzymatic turnover was not independent of its previous turnovers because of a slow fluctuation of protein conformation, was evidenced by spontaneous spectral fluctuation of FAD.

[Three dimensional finite element analysis of stress induced by orthodontic forces in the periodontal tissue]

The purpose of this study was to investigate the stress induced in the periodontal tissue of the upper central incisor by application of orthodontic forces. A three dimensional finite element model consist of tooth, periodontal ligament (PDL), cancellous and compact bone was established and the following results were obtained: (1) The highest stresses were observed on the root surface, the intermediate on the alveolar bone and the lowest in the PDL. (2) Stress condition on the surface of root and alveolar bone is very complex. The maximum, intermediate and minimum principle stresses on the same area are quite different, but the three principal stresses in the PDL are similar. (3) Regarding to tipping and torque movement, the stress value varied largely from the cervix to the apex, and there is stress concentration at the cervix and the apex. For bodily movement when M/F is -10.30, the stress induced is homogeneous and the difference of the stress values from the cervix to the apex is little, which seems to be more physiological.

Skeletal muscle ventricles: update after 18 months in circulation

Skeletal muscle ventricles (SMVs) have been constructed from canine latissimus dorsi muscle and connected to the aorta as aortic diastolic counterpulsators. Presently one dog remains alive and well with an SMV that has been functioning continuously in circulation for 18 months, without evidence of thromboembolic complications. SMVs are able to perform cardiac-type work with an output equal to that of the left ventricle at physiologic preloads, when tested with a mock circulation device in our laboratory. SMVs have been used for right-sided cardiac assist. In acute experiments these ventricles have functioned effectively, bypassing the right side of the heart for up to 8 h. Most recently we have tested SMVs using them chronically to pump blood in the right-sided circulation, and at the time of writing they have been shown to function effectively in this configuration for up to 18 days. SMVs may be used in the future as a method of treating patients with left- or right-sided heart failure.

Autologous skeletal muscle, an alternative for cardiac assistance

Original attempts to use skeletal muscle for cardiac assistance were soon abandoned when the problem of muscle fatigue could not be solved. In the last 2 decades, better understanding of muscle physiology and the development of successful protocols of electrical muscle conditioning have given new impetus to researchers around the world to proceed in the effort to identify useful applications of skeletal muscle to support the heart. More than 100 patients around the world have undergone cardiomyoplasty, mostly for cardiac failure. While subjective improvement in symptoms was noticed in the majority of the patients, only recently favorable hemodynamic changes have been documented. The other alternative that has been pursued in the laboratory is the construction of skeletal muscle ventricles that, after conditioning and vascular delay, have been shown to provide significant cardiac support when used for diastolic counterpulsation or for right heart bypass in animal models.

Experience with human immunodeficiency virus infection in patients with hepatitis B virus and hepatitis delta virus infections in Los Angeles, 1977-1985

Stored serum specimens from 723 patients with acute hepatitis B and 228 patients with chronic hepatitis B seen between 1977 and 1985 in the Hepatitis Clinic of the Los Angeles County-University of Southern California Medical Center, Los Angeles, CA, were tested for antibody to human immunodeficiency virus (anti-HIV). Risk factors were ordered hierarchically; cases with multiple risk factors were tabulated only in the risk group listed first on the clinic records. Anti-HIV was first detected in 1979, and by 1983 was found in about half of all homosexual men with chronic hepatitis B. The prevalence was significantly lower in patients with acute hepatitis B than in patients with chronic hepatitis B, and in nonhomosexual subjects compared with homosexual subjects. By 1985, 30 per cent of intravenous drug users with chronic hepatitis B were anti-HIV-positive. The highest annual seroconversion rate for anti-HIV, 21 per cent, was found in homosexual men in 1983. A significant association existed between anti-HIV positivity and hepatitis delta virus infection in homosexual men but not in drug abusers. This study provides data on the natural history of the human immunodeficiency virus epidemic in Los Angeles. Further study on the interaction of these different viruses is warranted.