SN2 Reaction at the Amide Nitrogen Center Enables Hydrazide Synthesis

Nucleophilic substitutions are fundamentally important transformations in synthetic organic chemistry. Despite the substantial advances in bimolecular nucleophilic substitutions (SN2) at saturated carbon centers, analogous SN2 reaction at the amide nitrogen atom remains extremely limited. Here we report an SN2 substitution method at the amide nitrogen atom with amine nucleophiles for nitrogen-nitrogen (N-N) bond formation that leads to a novel strategy toward biologically and medicinally important hydrazide derivatives. We found the use of sulfonate-leaving groups at the amide nitrogen atom played a pivotal role in the reaction. This new N-N coupling reaction allows the use of O-tosyl hydroxamates as electrophiles and readily available amines, including acyclic aliphatic amines and saturated N-heterocycles as nucleophiles. The reaction features mild conditions, broad substrate scope (>80 examples), excellent functional group tolerability, and scalability. The method is applicable to late-stage modification of various approved drug molecules, thus enabling complex hydrazide scaffold synthesis.

Long head of biceps tendon transposition for massive and irreparable rotator cuff tears: A systematic review and meta-analysis

BACKGROUND

Superior capsular reconstruction (SCR) with long head of biceps tendon (LHBT) transposition was developed to massive and irreparable rotator cuff tears (MIRCTs); however, the outcomes of this technique remain unclear.

AIM

To perform a systematic review of biomechanical outcomes and a meta-analysis of clinical outcomes after LHBT transposition for MIRCTs.

METHODS

We performed a systematic electronic database search on PubMed, EMBASE, and Cochrane Library. Studies of SCR with LHBT transposition were included according to the inclusion and exclusion criteria. Biomechanical studies were assessed for main results and conclusions. Included clinical studies were evaluated for quality of methodology. Data including study characteristics, cohort demographics, and outcomes were extracted. A meta-analysis was conducted of the clinical outcomes.

RESULTS

According to our inclusion and exclusion criteria, a total of six biomechanical studies were identified and reported an overall improvement in subacromial contact pressures and prevention of superior humeral migration without limiting range of motion (ROM) after LHBT transposition for MIRCTs. A total of five clinical studies were included in the meta-analysis of LHBT transposition outcomes, consisting of 253 patients. The results indicated that compared to other surgical methods for MIRCTs, LHBT transposition had advantages of more significant improvement in ROM (forward flexion mean difference [MD] = 6.54, 95% confidence interval [CI]: 3.07-10.01; external rotation [MD = 5.15, 95%CI: 1.59-8.17]; the acromiohumeral distance [AHD] [MD = 0.90, 95%CI: 0.21-1.59]) and reducing retear rate (odds ratio = 0.27, 95%CI: 0.15-0.48). No significant difference in American Shoulder and Elbow Surgeons score, visual analogue scale score, and University of California at Los Angles score was demonstrated between these two groups for MIRCTs.

CONCLUSION

In general, SCR with LHBT transposition was a reliable and economical technique for treating MIRCTs, both in terms of biomechanical and clinical outcomes, with comparable clinical outcomes, improved ROM, AHD, and reduced the retear rates compared to conventional SCR and other established techniques. More high-quality randomized controlled studies on the long-term outcomes of SCR with LHBT transposition are required to further assess.

Photo-Triggered, Copper(II) Chloride-Catalyzed Radical Hydroalkylation and Hydrosilylation of Vinylboronic Esters To Access Alkylboronic Esters

Alkyl boronic acids and their derivatives constitute vital building blocks in organic synthesis and are important motifs identified in medicinal chemistry. Herein, we present a phototriggered, CuCl2-catalyzed radical hydroalkylation and hydrosilylation of vinylboronic esters to alkylboronic esters. This approach exhibits mild reaction conditions, utilization of easily accessible reagents, and scalability up to a gram scale. Further synthetic transformations of the hydrosilylation products and mechanistic studies are also demonstrated.

Photoinduced C(sp3)-H borylation of alkanes mediated by copper(II) chloride

Alkyl boronic acid and its derivatives are important motifs in organic synthesis and pharmaceuticals. Herein, we report a photoinduced, CuCl₂ mediated C(sp³)-H borylation of unactivated alkanes. This protocol features mild reaction conditions, readily available reagents, and gram-scalability.

Bone marrow mesenchymal stem cell-derived exosomal microRNAs target PI3K/Akt signaling pathway to promote the activation of fibroblasts

BACKGROUND

Fibroblast plays a major role in tendon-bone healing. Exosomes derived from bone marrow mesenchymal stem cells (BMSCs) can activate fibroblasts and promote tendon-bone healing via the contained microRNAs (miRNAs). However, the underlying mechanism is not comprehensively understood. Herein, this study aimed to identify overlapped BMSC-derived exosomal miRNAs in three GSE datasets, and to verify their effects as well as mechanisms on fibroblasts.

AIM

To identify overlapped BMSC-derived exosomal miRNAs in three GSE datasets and verify their effects as well as mechanisms on fibroblasts.

METHODS

BMSC-derived exosomal miRNAs data (GSE71241, GSE153752, and GSE85341) were downloaded from the Gene Expression Omnibus (GEO) database. The candidate miRNAs were obtained by the intersection of three data sets. TargetScan was used to predict potential target genes for the candidate miRNAs. Functional and pathway analyses were conducted using the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases, respectively, by processing data with the Metascape. Highly interconnected genes in the protein-protein interaction (PPI) network were analyzed using Cytoscape software. Bromodeoxyuridine, wound healing assay, collagen contraction assay and the expression of COL I and α-smooth muscle actin positive were applied to investigate the cell proliferation, migration and collagen synthesis. Quantitative real-time reverse transcription polymerase chain reaction was applied to determine the cell fibroblastic, tenogenic, and chondrogenic potential.

RESULTS

Bioinformatics analyses found two BMSC-derived exosomal miRNAs, has-miR-144-3p and has-miR-23b-3p, were overlapped in three GSE datasets. PPI network analysis and functional enrichment analyses in the GO and KEGG databases indicated that both miRNAs regulated the PI3K/Akt signaling pathway by targeting phosphatase and tensin homolog (PTEN). In vitro experiments confirmed that miR-144-3p and miR-23b-3p stimulated proliferation, migration and collagen synthesis of NIH3T3 fibroblasts. Interfering with PTEN affected the phosphorylation of Akt and thus activated fibroblasts. Inhibition of PTEN also promoted the fibroblastic, tenogenic, and chondrogenic potential of NIH3T3 fibroblasts.

CONCLUSION

BMSC-derived exosomes promote fibroblast activation possibly through the PTEN and PI3K/Akt signaling pathways, which may serve as potential targets to further promote tendon-bone healing.

Short-segment fixation and transpedicular bone grafting for the treatment of thoracolumbar spine fracture

Purpose

Thoracolumbar fracture is one of the most common fractures of spine. And short-segment posterior fixation including the fractured vertebra (SSPFI) is usually used for the surgical treatment of it. However, the outcomes of SSPFI for different types of thoracolumbar fractures are not clear, and whether it is necessary to perform transpedicular bone grafting is still controversial. This study was conducted to determine the clinical efficacy of SSPFI for the treatment of different types of single-level thoracolumbar fracture, and make clear what kind of fractures need transpedicular bone grafting during the surgery.

Methods

Patients with single-level thoracolumbar fracture undergoing SSPFI surgery between January 2013 and June 2020 were included in this study. The operative duration, intraoperative blood loss, anterior vertebral height ratio (AVHR) and anterior vertebral height compressive ratio (AVHC) of the fractured vertebra, local kyphotic Cobb angle (LKA), vertebral wedge angle (VWA) and correction loss during follow up period were recorded. Outcomes between unilateral and bilateral pedicle screw fixation for fractured vertebra, between SSPFI with and without transpedicular bone grafting (TBG), and among different compressive degrees of fractured vertebrae were compared, respectively.

Results

A total of 161 patients were included in this study. All the patients were followed up, and the mean follow-upped duration was 25.2 ± 3.1 months (6-52 months). At the final follow-up, the AVHR was greater, and the LKA and VWA were smaller in patients with bilateral fixation (6-screw fixation) than those with unilateral fixation (5-screw fixation) of AO type A3/A4 fractures (P < 0.001). The correction loss of AVHR, LKA and VWA in fractured vertebra were significantly great when preoperative AVHC was >50% (P < 0.05). For patients with AVHC >50%, the correction loss in patients with TBG were less than those without TBG at the final follow-up (P < 0.05).

Conclusions

SSPFI using bilateral fixation was more effective than unilateral fixation in maintaining the fractured vertebral height for AO type A3/A4 fractures. For patients with AVHC >50%, the loss of correction was more obvious and it can be decreased by transpedicular bone grafting.

[Prevalence of mountain-zoonotic type visceral leishmaniasis in Yangquan City of Shanxi Province from 2015 to 2020]

OBJECTIVE

To investigate the prevalence of mountain-type zoonotic visceral leishmaniasis (MT-ZVL) in Yangquan City, Shanxi Province from 2015 to 2020, so as to provide the scientific evidence for formulating the MT-ZVL control strategy.

METHODS

The epidemiological data pertaining to MT-ZVL cases in Yangquan City from 2015 to 2020 were collected and descriptively analyzed. A Joinpoint regression model was created to analyze the trend in the MT-ZVL incidence in Yangquan City from 2015 to 2020 using annual percent change (APC). The sandflies surveillance data and the prevalence of Leishmania infections in dogs were collected in Yangquan City in 2020, and the regional distribution of sandflies density and sero-prevalence of Leishmania infections in dogs were calculated. In addition, the associations of sandflies density and sero-prevalence of Leishmania infections in dogs with the incidence of human MT-ZVL were examined using the linear correlation analysis.

RESULTS

A total of 162 MT-ZVL cases were reported in Yangquan City, Shanxi Province from 2015 to 2020, with annual mean incidence of 1.9/10⁵, and there were 4, 7, 16, 27, 33 cases and 75 cases with MT-ZVL reported from 2015 to 2020, appearing a tendency towards a rapid rise (APC = 72.79%, t = 11.10, P < 0.01). MT-ZVL cases were reported across the five counties (districts) of Yangquan City, and the cases predominantly occurred in Jiaoqu District (35.2%, 57/162) and Pingding County (33.3%, 54/162). MT-ZVL cases were predominantly detected in residents at ages of 15 years and older (71.6%, 116/162) and at ages of 0 to 2 years (22.2%, 36/162), with farmers (37.4%, 61/162) and diaspora children (24.5%, 40/162) as predominant occupations. The mean density of Phlebotomus chinensis was 6.3 sandflies per trap per night in Yangquan City from during the period from May to September, 2020, with the highest density observed in Jiaoqu District (12.6 sandflies per trap per night) and the lowest in Yuxian County (1.1 sandflies per trap per night), and there was a region-specific mean density of Ph. chinensis in Yangquan City (H = 17.282, P < 0.01). The sero-prevalence of serum anti-Leishmania antibody was 7.4% (2 996/40 573) in domestic dogs in Yangquan City, with the highest sero-prevalence seen in Jiaoqu District (16.6%, 1 444/8 677), and the lowest in Yuxian County (2.3%, 266/11 501), and there was a region-specific sero-prevalence rate of anti-Leishmania antibody in domestic dogs in Yangquan City (χ² = 1 753.74, P < 0.01). The sero-prevalence of anti-Leishmania antibody was significantly higher in stray dogs (20.0%, 159/794) than in domestic dogs (χ² = 176.63, P < 0.01). In addition, there were significant associations among the sandflies density, sero-prevalence of anti-Leishmania antibody in domestic dogs and the incidence of human MT-ZVL (r = 0.832 to 0.870, all P values < 0.05).

CONCLUSIONS

The prevalence of MT-ZVL appeared a tendency towards a rapid rise in Yangquan City from 2015 to 2020, and systematic interventions are urgently needed for MT-ZVL control.

LRIG2 regulates cell proliferation, migration and apoptosis of osteosarcoma

BACKGROUND

Osteosarcoma (OS) is one of the malignant bone tumors with strong aggressiveness and poor prognosis. Leucine-rich repeats and immunoglobulin-like domains2 (LRIG2) is closely associated with the poor prognosis of a variety of tumors, but the role of LRIG2 in osteosarcoma and the underlying molecular mechanism remains unclear.

OBJECTIVE

The aim of this study was to determine the function of LRIG2 in OS and the related molecular mechanism on cell proliferation, apoptosis and migration of OS.

METHODS

The mRNA and protein expression of LRIG2 in OS tissues and cells was detected by qRT-PCR, western blot (WB) assay and immunohistochemistry (IHC). The cell counting Kit-8 (CCK-8), clone formation, transwell, TdT-mediated dUTP Nick-End Labeling (TUNEL) and WB assay were applied to determine the proliferation, migration and apoptosis abilities of OS cells and its molecular mechanisms. Spontaneous metastasis xenografts were established to confirm the role of LRIG2 in vivo.

RESULTS

LRIG2 exhibited high expression in OS tissues and OS cell lines and the expression of which was significantly correlated with Enneking stage of patients, knockdown LRIG2 expression significantly inhibited OS cell proliferation, migration and enhanced apoptosis. Silencing LRIG2 also suppressed the growth of subcutaneous transplanted tumor in nude mice. Further, the mechanism investigation revealed that the protein level of cell proapoptotic proteins (Bax, caspase9 and caspase3) all increased attributed to LRIG2 deficiency, whereas expression of anti-apoptotic protein BCL2 decreased. LRIG2 silencing led to the decrease phosphorylation of AKT signaling, a decrease expression of vimentin and N-cadherin. Additionally, silencing LRIG2 significantly decreased the rate of tumor growth and tumor size.

CONCLUSIONS

LRIG2 acts as an oncogene in osteosarcoma, and it might become a novel target in the treatment of human OS.

Management of hip fracture in COVID-19 infected patients

Given that the global population of elderly individuals is expanding and the difficulty of recovery, hip fractures will be a huge challenge and a critical health issue for all of humanity. Although people have spent more time at home during the coronavirus disease 2019 (COVID-19) pandemic, hip fractures show no sign of abating. Extensive studies have shown that patients with hip fracture and COVID-19 have a multifold increase in mortality compared to those uninfected and a more complex clinical condition. At present, no detailed research has systematically analyzed the relationship between these two conditions and proposed a comprehensive solution. This article aims to systematically review the impact of COVID-19 on hip fracture and provide practical suggestions. We found that hip fracture patients with COVID-19 have higher mortality rates and more complicated clinical outcomes. Indirectly, COVID-19 prevents hip fracture patients from receiving regular medical treatment. With regard to the problems we encounter, we provide clinical recommendations based on existing research evidence and a clinical flowchart for the management of hip fracture patients who are COVID-19 positive. Our study will help clinicians adequately prepare in advance when dealing with such patients and optimize treatment decisions.

[Prediction of trends for fine-scale spread of Oncomelania hupensis in Shanghai Municipality based on supervised machine learning models]

OBJECTIVE

To predict the trends for fine-scale spread of Oncomelania hupensis based on supervised machine learning models in Shanghai Municipality, so as to provide insights into precision O. hupensis snail control.

METHODS

Based on 2016 O. hupensis snail survey data in Shanghai Municipality and climatic, geographical, vegetation and socioeconomic data relating to O. hupensis snail distribution, seven supervised machine learning models were created to predict the risk of snail spread in Shanghai, including decision tree, random forest, generalized boosted model, support vector machine, naive Bayes, k-nearest neighbor and C5.0. The performance of seven models for predicting snail spread was evaluated with the area under the receiver operating characteristic curve (AUC), F1-score and accuracy, and optimal models were selected to identify the environmental variables affecting snail spread and predict the areas at risk of snail spread in Shanghai Municipality.

RESULTS

Seven supervised machine learning models were successfully created to predict the risk of snail spread in Shanghai Municipality, and random forest (AUC = 0.901, F1-score = 0.840, ACC = 0.797) and generalized boosted model (AUC= 0.889, F1-score = 0.869, ACC = 0.835) showed higher predictive performance than other models. Random forest analysis showed that the three most important climatic variables contributing to snail spread in Shanghai included aridity (11.87%), ≥ 0 °C annual accumulated temperature (10.19%), moisture index (10.18%) and average annual precipitation (9.86%), the two most important vegetation variables included the vegetation index of the first quarter (8.30%) and vegetation index of the second quarter (7.69%). Snails were more likely to spread at aridity of < 0.87, ≥ 0 °C annual accumulated temperature of 5 550 to 5 675 °C, moisture index of > 39% and average annual precipitation of > 1 180 mm, and with the vegetation index of the first quarter of > 0.4 and the vegetation index of the first quarter of > 0.6. According to the water resource developments and township administrative maps, the areas at risk of snail spread were mainly predicted in 10 townships/subdistricts, covering the Xipian, Dongpian and Tainan sections of southern Shanghai.

CONCLUSIONS

Supervised machine learning models are effective to predict the risk of fine-scale O. hupensis snail spread and identify the environmental determinants relating to snail spread. The areas at risk of O. hupensis snail spread are mainly located in southwestern Songjiang District, northwestern Jinshan District and southeastern Qingpu District of Shanghai Municipality.

[Comparison of follow-up treatment regimens for colorectal cancer liver metastases without objective response to neoadjuvant chemotherapy: direct surgery or surgery after second-line chemotherapy]

Objective: To compare the effect of direct surgery or surgery after second-line chemotherapy for colorectal cancer patients with liver metastases who did not achieve objective remission after neoadjuvant chemotherapy. Methods: A retrospective case cohort study was used. The clinical and pathological data of 107 patients with colorectal cancer liver metastases who did not achieve objective response to neoadjuvant chemotherapy at Department of Hepatobiliary Surgery,Cancer Hospital,Chinese Academy of Medical Sciences from December 2008 to December 2016 were retrospectively collected. There were 71 males and 36 females, median age was 57 years (range: 28 to 79 years). According to the different treatment regimens after neoadjuvant chemotherapy,107 cases were divided into a direct surgery group (direct group,n=65) and an operation after receiving second-line chemotherapy group (second-line group,n=42). The propensity score matching(PSM) of the Logistic regression model was used to match the bilobar distribution of liver metastases and the number of first-line chemotherapy cycles in the two groups of patients. The caliper value was set to 0.10 and the matching ratio was 1∶2. T test, Mann-Whitney U test, χ² test or Fisher's exat test was used to analyzed the data between the tuo groups, respectively. Survival analysis design was used to investigate the difference in prognosis between the two groups of patients. Results: The follow-up time(M(IQR)) was 56.3(34.3) months (range: 2.1 to 95.0 months),and all patients were followed up. After PSM,there were 28 cases in the direct group and 42 cases in the second-line group, there were no significant differences in whether R0 resection was feasible,blood loss,blood transfusion,postoperative complications and postoperative hospital stay between the two groups (all P>0.05). The 1,3,and 5-year progression-free survival(PFS) rates of the direct group were 40.0%,16.5%,and 11.0%,and the 1,3,and 5-year overall survival(OS) rates were 98.5%,61.2%,and 41.4%,respectively, the second-line group 1,3,5 years PFS rates were 35.7%,14.3%,14.3%,1,3,5-year OS rate were 95.2%,55.1%,44.4%,respectively. The median PFS time of the direct group and the second-line group was 8.5 months and 7.5 months,respectively,and the difference was not statistically significant (P=0.826). The median OS time of the direct group and the second-line group were 33.8 months and 46.9 months,respectively. The difference was not statistically significant(P=0.646).The median PFS time of the direct group and second-line chemotherapy complete remission and partial remission group(CR/PR group) was 10.2 months and 9.1 months,respectively,and the difference was not statistically significant(P=0.669). The median OS time of the direct group and the second-line CR/PR group was 51.0 months and 46.9 months,respectively,and the difference was not statistically significant(P=0.427). The results of survival analysis suggested that major liver resection was an independent prognosis factor for PFS (HR=1.809,95%CI: 1.067 to 3.067,P=0.028) and OS(HR=2.751,95%CI: 1.317 to 5.747,P=0.007). Second-line chemotherapy was not an independent prognostic factor for PFS (HR=0.945, 95%CI:0.570 to 1.567,P=0.828) and OS (HR=0.866,95%CI: 0.468 to 1.602,P=0.646). Conclusions: There is no significant difference in the short-term outcome and long-term prognosis between direct surgery patients and second-line chemotherapy followed by surgery. Second-line chemotherapy is not an independent prognostic factor for colorectal cancer liver metastases patients who fail to achieve objective response after neoadjuvant chemotherapy.

Comment on “Outcomes of different minimally invasive surgical treatments for vertebral compression fractures: An observational study”

Recently we read the article entitled “Outcomes of different minimally invasive surgical treatments for vertebral compression fractures: An observational study”. This was an observational study that reviewed the safety and efficacy of different cement augmentation modalities for vertebral compression fractures under osteoporotic condition. Overall, this is a valuable study that can provide a reference for clinical practice. On the other hand, we also noticed some points in the article and are willing to share our views. Further studies with a higher level of evidence can add more knowledge regarding relevant concerns.

Physical energy-based ultrasound shifts M1 macrophage differentiation towards M2 state

Recently, we read with interest the article entitled “Unveiling the Morphogenetic Code: A New Path at the Intersection of Physical Energies and Chemical Signaling”. In this paper, the investigation into the systematic and comprehensive bio-effects of physical energies prompted us to reflect on our research. We believe that ultrasound, which possesses a special physical energy, also has a certain positive regulatory effect on macrophages, and we have already obtained some preliminary research results that support our hypothesis.

Application of Machine Learning Techniques to Predict Bone Metastasis in Patients with Prostate Cancer

Objective

This study aimed to develop and validate a machine learning model for predicting bone metastases (BM) in prostate cancer (PCa) patients.

Methods

Demographic and clinicopathologic variables of PCa patients in the Surveillance, Epidemiology and End Results (SEER) database from 2010 to 2017 were retrospectively analyzed. We used six different machine learning algorithms, including Decision tree (DT), Random forest (RF), Multilayer Perceptron (MLP), Logistic regression (LR), Naive Bayes classifiers (NBC), and eXtreme gradient boosting (XGB), to build prediction models. External validation using data from 644 PCa patients of the First Affiliated Hospital of Nanchang University from 2010 to 2016. The performance of the models was evaluated using the area under receiver operating characteristic curve (AUC), accuracy score, sensitivity (recall rate) and specificity. A web predictor was developed based on the best performance model.

Results

A total of 207,137 PCa patients from SEER were included in this study. Of whom, 6725 (3.25%) developed BM. Gleason score, Prostate-specific antigen (PSA) value, T, N stage and age were found to be the risk factors of BM. The XGB model offered the best predictive performance among these 6 models (AUC: 0.962, accuracy: 0.884, sensitivity (recall rate): 0.906, and specificity: 0.879). An XGB model-based web predictor was developed to predict BM in PCa patients.

Conclusion

This study developed a machine learning model and a web predictor for predicting the risk of BM in PCa patients, which may help physicians make personalized clinical decisions and treatment strategy for patients.

Exosomes derived from inflammatory myoblasts promote M1 polarization and break the balance of myoblast proliferation/differentiation

BACKGROUND

Acute muscle injuries are one of the most common injuries in sports. Severely injured muscles are prone to re-injury due to fibrotic scar formation caused by prolonged inflammation. How to regulate inflammation and suppress fibrosis is the focus of promoting muscle healing. Recent studies have found that myoblasts and macrophages play important roles in the inflammatory phase following muscle injury; however, the crosstalk between these two types of cells in the inflammatory environment, particularly the exosome-related mechanisms, had not been well studied.

AIM

To evaluate the effects of exosomes from inflammatory C2C12 myoblasts (IF-C2C12-Exos) on macrophage polarization and myoblast proliferation/differentiation.

METHODS

A model of inflammation was established in vitro by lipopolysaccharide stimulation of myoblasts. C2C12-Exos were isolated and purified from the supernatant of myoblasts by gradient centrifugation. Multiple methods were used to identify the exosomes. Gradient concentrations of IF-C2C12-Exos were added to normal macrophages and myoblasts. PKH67 fluorescence tracing was used to identify the interaction between exosomes and cells. Microscopic morphology, Giemsa stain, and immunofluorescence were carried out for histological analysis. Additionally, ELISA assays, flow cytometry, and western blot were conducted to analyze molecular changes. Moreover, myogenic proliferation was assessed by the BrdU test, scratch assay, and CCK-8 assay.

RESULTS

We found that the PKH-67-marked C2C12-Exos can be endocytosed by both macrophages and myoblasts. IF-C2C12-Exos induced M1 macrophage polarization and suppressed the M2 phenotype in vitro. In addition, these exosomes also stimulated the inflammatory reactions of macrophages. Furthermore, we demonstrated that IF-C2C12-Exos disrupted the balance of myoblast proliferation/differentiation, leading to enhanced proliferation and suppressed fibrogenic/myogenic differentiation.

CONCLUSION

IF-C2C12-Exos can induce M1 polarization, resulting in a sustained and aggravated inflammatory environment that impairs myoblast differentiation, and leads to enhanced myogenic proliferation. These results demonstrate why prolonged inflammation occurs after acute muscle injury and provide a new target for the regulation of muscle regeneration.

New-onset depression after hip fracture surgery among older patients: Effects on associated clinical outcomes and what can we do?

BACKGROUND

Hip fracture in the elderly is a worldwide medical problem. New-onset depression after hip fracture has also received attention because of its increasing incidence and negative impact on recovery.

AIM

To provide a synthesis of the literature addressing two very important questions arising from postoperative hip fracture depression (PHFD) research: the risk factors and associated clinical outcomes of PHFD, and the optimal options for intervention in PHFD.

METHODS

We searched the PubMed, Web of Science, EMBASE, and PsycINFO databases for English papers published from 2000 to 2021.

RESULTS

Our results showed that PHFD may result in poor clinical outcomes, such as poor physical function and more medical support. In addition, the risk factors for PHFD were summarized, which made it possible to assess patients preoperatively. Moreover, our work preliminarily suggested that comprehensive care may be the optimal treatment option for PHFDs, while interdisciplinary intervention can also be clinically useful.

CONCLUSION

We suggest that clinicians should assess risk factors for PHFDs preoperatively, and future research should further validate current treatment methods in more countries and regions and explore more advanced solutions.

Machine learning for the prediction of bone metastasis in patients with newly diagnosed thyroid cancer

OBJECTIVES

This study aimed to establish a machine learning prediction model that can be used to predict bone metastasis (BM) in patients with newly diagnosed thyroid cancer (TC).

METHODS

Demographic and clinicopathologic variables of TC patients in the Surveillance, Epidemiology, and End Results database from 2010 to 2016 were retrospectively analyzed. On this basis, we developed a random forest (RF) algorithm model based on machine-learning. The area under receiver operating characteristic curve (AUC), accuracy score, recall rate, and specificity are used to evaluate and compare the prediction performance of the RF model and the other model.

RESULTS

A total of 17,138 patients were included in the study, with 166 (0.97%) developed bone metastases. Grade, T stage, histology, race, sex, age, and N stage were the important prediction features of BM. The RF model has better predictive performance than the other model (AUC: 0.917, accuracy: 0.904, recall rate: 0.833, and specificity: 0.905).

CONCLUSIONS

The RF model constructed in this study could accurately predict bone metastases in TC patients, which may provide clinicians with more personalized clinical decision-making recommendations. Machine learning technology has the potential to improve the development of BM prediction models in TC patients.

Comparison of three administration modes for establishing a zebrafish seizure model induced by N-Methyl-D-aspartic acid

BACKGROUND

Epilepsy is a complex neurological disorder characterized by recurrent, unprovoked seizures resulting from the sudden abnormal discharge of brain neurons. It leads to transient brain dysfunction, manifested by abnormal physical movements and consciousness. It can occur at any age, affecting approximately 65 million worldwide, one third of which are still estimated to suffer from refractory seizures. There is an urgent need for further establishment of seizure models in animals, which provides an approach to model epilepsy and could be used to identify novel anti-epileptic therapeutics in the future.

AIM

To compare three administration modes for establishing a seizure model caused by N-Methyl-D-aspartic acid (NMDA) in zebrafish.

METHODS

Three administration routes of NMDA, including immersion, intravitreal injection and intraperitoneal injection, were compared with regard to their effects on inducing seizure-like behaviors in adult zebrafish. We evaluated neurotoxicity by observing behavioral changes in zebrafish and graded those behaviors with a seizure score. In addition, the protective effects of MK-801 (Dizocilpine) and natural active constituent resveratrol against NMDA-induced alterations were studied.

RESULTS

The three NMDA-administration methods triggered different patterns of the epileptic process in adult zebrafish. Seizure scores were increased after increasing NMDA concentration regardless of the mode of administration. However, the curve of immersion continuously rose to a high plateau (after 50 min), while the curves of intravitreal injection and intraperitoneal injection showed a spike in the early stage (10-20 min) followed by a steady decrease in seizure scores. Furthermore, pretreatment with resveratrol and MK-801 significantly delayed seizure onset time and lowered seizure scores.

CONCLUSION

By comparing the three methods of administration, intravitreal injection of NMDA was the most suitable for establishing an acute epileptic model in zebrafish. Thus, intraperitoneal injection in zebrafish can be applied to simulate diseases such as epilepsy. In addition, NMDA immersion may be an appropriate method to induce persistent seizures. Moreover, MK-801 and resveratrol showed strong anti-epileptic effects; thus, both of them may be clinically valuable treatments for epilepsy.

Comparative analysis of the gut microbiota of Apis cerana in Yunnan using high-throughput sequencing

Gut microbes play an important role in host disease and health. The Asian honey bee Apis cerana is an important pollinator of agricultural crops in China. However, there are still few studies on the structure and composition of the microbiota in the intestine of A. cerana, especially A. cerana in Yunnan. To understand the species and composition of the microbiota in the intestine of A. cerana in Yunnan, we used high-throughput sequencing technology to carry out 16S rRNA sequencing on 50 samples from Kunming, Xishuangbanna and Mengzi. The results show that both from the phylum level and the genus level, the structure and abundance of the microbiota in the gut of A. cerana from the three regions tended to be the same. At the phylum level, the abundance of Proteobacteria, Firmicutes, Bacteroidetes, Actinobacteria, Acidobacteria and other species was high in A. cerana from different areas. At the genus level, the abundance of Lactobacillus, Gilliamella, Snodgrassella, Apibacter, Candidatus Schmidhempelia and other species was high in A. cerana from different areas. Due to its unique geographical environment and climatic conditions, at the genus level, the diversity of bacterial communities in Xishuangbanna was significantly lower than that in the other two regions, which was about 100 genera less. In conclusion, our results reveal the composition and structure of the intestinal microbiota of bees in Yunnan and deepen our understanding of the intestinal microbiota of bees.

The impact of mercury on the genome-wide transcription profile of zebrafish intestine

Mercury is a widely used heavy metal that causes pollution to aquatic environments and severely affects the health of fish. Little is known about how heavy metal pollutants affect fish, particularly for gene expression within important organs such as the intestine. Herein, whole transcriptome sequencing was performed on zebrafish (Danio rerio) intestine tissue after HgCl₂ (HGC, 30 μg/L) exposure. A total of 2,257 differentially expressed genes (DEGs) were identified, including 1,788 up- and 469 down-regulated genes. Functional enrichment analysis revealed that these DEGs were primarily related to xenobiotic biodegradation, biomacromolecule metabolism, development, oxidative defense, and immune response. Ten key HGC-responsive DEGs were screened to survey the dynamic changes of expression in response to HGC exposure at different time points, and were also used to validate RNA sequencing data using quantitative real-time PCR (qPCR). Results indicate that the expression of genes encoding UGT1AB, GSTT1B, GSTO1, GSTM2, UGT5G1, GSTT1A, GSTR, GSTM3, GSTA1, and GSTP2 were significantly upregulated in response to the HGC exposure, and potentially help to counteract the adverse effects of HGC. This study provides insight into fish molecular toxicological responses to heavy metals and method on environmental risk assessment.

MicroRNA profile of immune response in gills of zebrafish (Danio rerio) upon Staphylococcus aureus infection

The gills of fish are large mucosal surfaces that are very important portals for pathogen entry. Investigations have shown that microRNAs (miRNAs) are key regulators of immune response to bacterial infections in the gills of fish; however, how miRNA expression changes in response to infection by Gram-positive bacteria remains largely unknown. To further investigate the immunological role of miRNAs in fish gills under pathogen stress induced by Gram-positive bacterial infection, this study investigated Staphylococcus aureus (SA)-induced changes in the miRNAs levels in gills of adult zebrafish (Danio rerio). miRNA microarrays were used to analyze expression profiles of known miRNA in the gills of zebrafish in response to SA infection and compared these to uninfected control fish. A total of 30 differentially expressed miRNAs (DEMs) were identified. Target genes likely regulated by DEMs were predicted, and functional enrichment analyses were performed. The results indicated that DEM targets were primarily involved in innate immune processes, apoptosis, defense responses, and antibacterial responses. Pathways involving bacterial infection, innate immunity, metabolic process, disease, and apoptosis were mediated by DEMs. Furthermore, real-time quantitative PCR experiments for nine key SA-responsive DEMs that regulated the "SA infection" pathway validated the accuracy of microarray results. Dynamic variations in gene expression were surveyed in detail for these key SA-responsive DEMs for PBS control and at 6, 12, 24, and 48 h after SA challenge in detail. This study provides novel insight into the mechanisms underlying the miRNA regulation during the SA-induced immune response in zebrafish gills, and provides basic knowledge on the innate immune response against Gram-positive bacterial infection in bony fish.

Establishment of an adult zebrafish model of retinal neurodegeneration induced by NMDA

AIM

To establish a model of retinal neurodegeneration induced by N-Methyl-D-aspartic acid (NMDA) in adult zebrafish.

METHODS

We compared the effects of three different NMDA delivery methods on retinal neurodegeneration in adult zebrafish: immersion (I.M.), intravitreal injection (I.V.), and intraperitoneal injection (I.P.), and examined retinal pathology and degeneration by hematoxylin and eosin and TUNEL staining in the treated zebrafish. Effects of the NMDA receptor antagonist MK-801 and the natural product resveratrol on NMDA-induced retinal neurodegeneration were also assessed.

RESULTS

The thickened inner retina was seen in histology with 100 µmol/L NMDA by I.M. administration. Significant apoptosis in the retinal ganglion cell layer and retinal thickness reduction occurred in 0.5 mol/L NMDA I.P. administration group.Seizure-like behavioral changes, but no retinal histological alteration occurred in 16 mg/kg NMDA I.P. administration group. Resveratrol and MK-801 prevented NMDA-induced retinal neurodegeneration in the zebrafish.

CONCLUSION

Among the three drug administration methods, I.V. injection of NMDA is the most suitable for establishment of an acute retinal damage model in zebrafish. I.M. with NMDA is likely the best for use as a chronic retinal damage model. I.P. treatment with NMDA causes brain damage. Resveratrol and MK801 may be a clinically valuable treatment for retinal neurodegeneration.

Human cytomegalovirus UL49 encodes an early, virion-associated protein essential for virus growth in human foreskin fibroblasts

Despite recent results of deletion experiments showing that open reading frame (ORF) UL49 of human cytomegalovirus (HCMV) is essential, the expression, function and functional location of its encoded protein remain unknown. We generated an antibody specific for pUL49 to investigate the protein product encoded by the UL49 ORF and identified its function in HCMV-infected host foreskin fibroblasts. A bacterial artificial chromosome (BAC) of HCMV strain Towne (pRV-Towne) and the UL49-deleted mutant pRV-delUL49Towne were used to observe virus growth by plaque assay. Using a UL49-protein-binding antibody, we located pUL49 in the fibroblast cytoplasm. pUL49 exhibited expression kinetics resembling those of the class β-2 proteins and was detected in the virion tegument. Following deletion of UL49 ORF, the virus failed to replicate, but it could be recovered by addition of pUL49 from pCDNA3.1 (+)-UL49. Our findings indicate that UL49 ORF is essential for HCMV replication in host foreskin fibroblasts.

Therapeutic effects of folic acid against precancerous lesions in patients with chronic atrophic gastritis

AIM: To evaluate the therapeutic effect of folic acid against intestinal metaplasia (IM) and atypical hyperplasia (ATP).

METHODS: One hundred and one patients with chronic atrophic gastritis (accompanied with IM and ATP) were randomly divided into either a trial group or a control group. Before treatment, Helicobacter pylori (H. pylori) carriers received eradication treatment with routine quadruple chemotherapy for ten days. Patients of the trial group received treatment with folic acid and traditional Chinese medicine Weifuchun, while patients of the control group were treated with Weifuchun only. The treatment duration was 6 mo in both groups. The improvement in clinical symptoms and histological findings was compared between the two groups.

RESULTS: Compared to the control group, the trail group had significantly improved clinical symptoms and histological findings for IM and ATP (84.91% vs 41.67%, 70.27% vs 45.45%, 68.75% vs 33.33%; P < 0.001, P < 0.05, P < 0.05).

CONCLUSION: Combination therapy with folic acid and Weifuchun is safer and more effective than Weifuchun alone in the treatment of precancerous gastric lesions IM and ATP.

First Report of Leaf Spot Disease Caused by Exserohilum rostratum on Pineapple in Hainan Province, China

Pineapple (Ananas comosus (L.) Merr.) is an important perennial monocotyledonous plant that serves as an important fruit crop globally and is also produced in the Hainan Province of China where production in 2009 was 296,600 t. In July 2009, atypical symptoms of a leaf spot disease were observed on mature pineapple leaves in Chengmai County; approximately 15% of plants propagated from suckers became symptomatic after 150 to 300 days, eventually causing a 3 to 10% yield loss. In the initial infection stage, grayish white-to-yellowish white spots emerged on the leaf surfaces that ranged from 1.0 to 2.4 × 0.3 to 0.7 cm; black specks were not always present in the spots. Leaf spots also had distinctive light brown-to-reddish brown banding pattern on the edges. Several spots would often merge to form large lesions, 6.5 to 15.4 × 2.5 to 5.6 cm, covering more than 67% of the leaf surface, which can lead to death of the plant. Infected pineapple leaves collected from an orchard of Chengmai County were surface sterilized (75% ethanol for 30 s, 0.1% HgCl₂ for 2 min, and rinsed three times in sterile distilled water). Leaf pieces were placed on potato dextrose agar medium and then incubated at 25°C. The emerging fungal colonies were grayish white to brown. Similar strains were obtained from Qionghai City and Wanning City subsequently. Two isolates, ITF0706-1 and ITF0706-2, were used in confirmation of the identity of the pathogen and in pathogenicity tests. Colonies were fast growing (more than 15 mm per day at 25 to 30°C) with dense aerial mycelia. Conidia were fusiform, pyriform to oval or cylindrical, olive brown to dark brown, 3 to 10 septate (typically 5 to 8), 33.2 to 102.5 × 9.0 to 21.3 μm, with a strongly protruding hilum bulged from the basal cell, which were similar to the Type A conidia described by Lin et al. (3). The strains were subjected to PCR amplification of the internal transcribed spacer (ITS)1-5.8S-ITS2 regions with universal primer pair ITS1/ITS4. The ITS sequence comparisons (GenBank Accession Nos. JN711431 and JN711432) shared between 99.60 and 99.83% identity with the isolate CATAS-ER01 (GenBank Accession No. GQ169762). According to morphological and molecular analysis, the two strains were identified as Exserohilum rostratum (Drechs.) Leonard & Suggs. Pathogenicity experiments were conducted five times and carried out by spraying a conidial suspension (10⁵ CFU/ml) on newly matured leaves of healthy pineapple plants; plants sprayed with sterile water served as the negative control. Plants were incubated in the growth chamber at 20 to 25°C. Symptoms of leaf spot developed on test plants 7 days after inoculation while the control plants remained asymptomatic. Koch's postulates were fulfilled with the reisolation of the two fungal strains. Currently, E. rostratum is one of the most common pathogens on Bromeliads in Florida (2) and has been reported on Zea mays (4), Musa paradisiacal (3), and Calathea picturata (1) in China, but to our knowledge, this is the first report of leaf spot disease caused by E. rostratum on pineapple in Hainan Province of P.R. China. References: (1) L. L. Chern et al. Plant Dis. 95:1033, 2011. (2) R. M. Leahy. Plant Pathol. Circ. No. 393. Florida Department of Agriculture and Consumer Services Division of Plant Industry, 1999. (3) S. H. Lin et al. Australas. Plant Pathol. 40:246, 2011. (4) J. N. Tsai et al. Plant Pathol. Bull. 10:181, 2001.

Why do essential proteins tend to be clustered in the yeast interactome network?

Recently, the debate on the centrality-lethality rule is resolved by the "second-generation" high-throughput Y2H data from the yeast interactome network, which suggests no significant correlation between the degree of connectedness and essentiality of proteins. However, it is still not clear why essential proteins strongly tend to interact with each other. Previously, the concept of essential protein-protein interactions was proposed to explain the mechanism underlying the clustering of essential proteins. In this article we show that 67 to 75% of the excessive interactions between essential proteins (IBEPs) in the yeast interactome network can be attributed to interactions within protein complexes characterised by the same deletion phenotype for subunits within the complex. Furthermore, 20 to 78% of the excess in IBEPs are caused by the strongly modular structure of the network and by variation in protein essentiality among modules. Not only do proteins function as an interactive network in cellular processes, but furthermore, many proteins do not take part in the network alone, but integrate into protein complexes and many functionally related complexes integrate into modules. So, the local structure of protein complexes as both functional and structural modules are the main contributory factors in the clustering of essential proteins.

Impacts of yeast metabolic network structure on enzyme evolution

Vitkup et al. recently presented an analysis of the influence of yeast metabolic network structure on enzyme evolution; different conclusions are reached when modularity is properly accounted for.

A comment on D Vitkup, P Kharchenko and A Wagner: Influence of metabolic network structure and function on enzyme evolution. Genome Biol 2006, 7:R39.

The E-cadherin gene polymorphism 160C->A and cancer risk: A HuGE review and meta-analysis of 26 case-control studies

A single nucleotide polymorphism, - 160C-->A, has been identified in the promoter region of the E-cadherin gene and has been shown to alter its transcriptional activity. To assess susceptibility of -160A allele carriers to seven types of cancers, the authors conducted a comprehensive meta-analysis, up to November 2006, of 26 case-control studies comprising 7,042 cases and 7,011 controls. Pooled odds ratios and 95% confidence intervals were calculated by using the random-effects model. Publication bias, subgroup, and sensitivity analyses were also performed, which showed that -160A allele carriers, compared with noncarriers, had about a 17-19% increased risk of several invasive/metastatic tumors. Analyses of various types of cancers revealed that, in Europeans, the -160AA homozygote was associated with an increased risk of urothelial cancer, carriers of -160A were at increased risk of lung and prostate cancers, and carriers of -160A with gastric cancer were found to suffer a significantly increased risk, whereas their Asian counterparts seemed to be tolerant. No evidence was found that the -160A allele predisposed its carriers to breast, colorectal, or esophageal cancers. These findings indicate that -160A of the E-cadherin gene is emerging as a low-penetrance tumor susceptibility allele for the development of gastric, lung, prostate, and urothelial cancers.

High frequency of level II-V lymph node involvement in RET/PTC positive papillary thyroid carcinoma

AIMS

To investigate the frequency and clinical significance of RET rearrangement in Chinese patients with papillary thyroid carcinoma (PTC) and discuss the role of RET rearrangement in therapeutic decision-making after the performance of level VI lymph node dissection and the 2002 AJCC staging system.

METHODS

RET/PTC-1 and RET/PTC-3 were detected in 126 PTCs using reverse transcription-polymerase chain reaction (RT-PCR) and direct sequencing.

RESULTS

RET rearrangement was detected in 18 cases of PTC. The patient group aged < 20 years had the highest frequency (3/6) of RET rearrangement among the age groups (< 20 years, 20-40 years and > or = 40 years; P=0.03). RET/PTC-1 positive patients were more likely to suffer from Hashimoto's thyroiditis simultaneously (P=0.02) while RET/PTC-3 positive patients had a higher frequency of extrathyroidal extension (P<0.01) and advanced T classification (P<0.01). RET rearrangement (OR=8.70, 95% CI 1.69-44.81), male (OR=3.88, 95% CI 1.41-10.69), age (OR=0.96, 95% CI 0.93-0.99), multifocality (OR=3.54, 95% CI 1.33-9.41) and advanced T classification (OR=7.32, 95% CI 2.91-18.40) were all identified as risk factors of level II-V lymph node involvement in the multivariate analysis.

CONCLUSIONS

The frequency of RET rearrangement in Chinese patients is low and age related. RET/PTC-1 and RET/PTC-3 are associated with different clinical pathological characteristics but not with lymph node involvement. The RET/PTC positive patients should receive more attention to lateral neck in the management of PTC.

Genetic dissection of ethanol tolerance in the budding yeast Saccharomyces cerevisiae

Uncovering genetic control of variation in ethanol tolerance in natural populations of yeast Saccharomyces cerevisiae is essential for understanding the evolution of fermentation, the dominant lifestyle of the species, and for improving efficiency of selection for strains with high ethanol tolerance, a character of great economic value for the brewing and biofuel industries. To date, as many as 251 genes have been predicted to be involved in influencing this character. Candidacy of these genes was determined from a tested phenotypic effect following gene knockout, from an induced change in gene function under an ethanol stress condition, or by mutagenesis. This article represents the first genomics approach for dissecting genetic variation in ethanol tolerance between two yeast strains with a highly divergent trait phenotype. We developed a simple but reliable experimental protocol for scoring the phenotype and a set of STR/SNP markers evenly covering the whole genome. We created a mapping population comprising 319 segregants from crossing the parental strains. On the basis of the data sets, we find that the tolerance trait has a high heritability and that additive genetic variance dominates genetic variation of the trait. Segregation at five QTL detected has explained approximately 50% of phenotypic variation; in particular, the major QTL mapped on yeast chromosome 9 has accounted for a quarter of the phenotypic variation. We integrated the QTL analysis with the predicted candidacy of ethanol resistance genes and found that only a few of these candidates fall in the QTL regions.

Average Gene Length Is Highly Conserved in Prokaryotes and Eukaryotes and Diverges Only Between the Two Kingdoms

The average length of genes in a eukaryote is larger than in a prokaryote, implying that evolution of complexity is related to change of gene lengths. Here, we show that although the average lengths of genes in prokaryotes and eukaryotes are much different, the average lengths of genes are highly conserved within either of the two kingdoms. This suggests that natural selection has clearly set a strong limitation on gene elongation within the kingdom. Furthermore, the average gene size adds another distinct characteristic for the discrimination between the two kingdoms of organisms.

Constructing genetic linkage maps under a tetrasomic model

An international consortium has launched the whole-genome sequencing of potato, the fourth most important food crop in the world. Construction of genetic linkage maps is an inevitable step for taking advantage of the genome projects for the development of novel cultivars in the autotetraploid crop species. However, linkage analysis in autopolyploids, the kernel of linkage map construction, is theoretically challenging and methodologically unavailable in the current literature. We present here a theoretical analysis and a statistical method for tetrasomic linkage analysis with dominant and/or codominant molecular markers. The analysis reveals some essential properties of the tetrasomic model. The method accounts properly for double reduction and incomplete information of marker phenotype in regard to the corresponding phenotype in estimating the coefficients of double reduction and recombination frequency and in testing their significance by using the marker phenotype data. Computer simulation was developed to validate the analysis and the method and a case study with 201 AFLP and SSR markers scored on 228 full-sib individuals of autotetraploid potato is used to illustrate the utility of the method in map construction in autotetraploid species.

Novel microdeletion in the transforming growth factor β type II receptor gene is associated with giant and large cell variants of nonsmall cell lung carcinoma

Mutations in the tumor suppressor gene transforming growth factor beta (TGFB) Type II receptor (TGFBR2) are frequently found in many cancers with microsatellite instability, but are less common in lung cancer. In the present study, we looked for mutations in TGFBR2 in nonsmall cell lung carcinoma (NSCLC) cells and tissues. A novel homozygous microdeletion (c.492_507del) was identified in two cell lines derived from the same giant cell carcinoma (GCC) and was confirmed in the corresponding tumor tissues. Furthermore, a heterozygous c.492_507del was found in the germ-line of one patient, as well as in the other GCC cases and some large cell carcinomas (LCC) but not in other subtypes of NSCLC. The 16 bp-microdeletion introduced a premature stop codon at positions 590-592 of the cDNA, resulting in a truncated TGFBR2 protein with a mutated transmembrane domain and loss of kinase domain. The GCC cells were characterized as being unresponsive to TGFB induction both in growth inhibition and stimulation of extracellular matrix protein. Moreover, after the reconstitution of wild-type TGFBR2 expression, the sensitivity to TGFB was restored. Therefore, mutated TGFBR2 seems to play an important role in the abrogation of TGFB signal transduction in GCC cells.

[Screening and detecting of proteins interacting with mPem]

mPem, a homeobox gene, is expressed in a time and stage specific manner during murine ontogeny. Pem transcripts are abundant in 7- and 8-day mouse embryos, but decrease precipitously thereafter. On Day 9 they become abundant in placenta and yolk sac, persisting there until parturition. Although Pem transcripts are not detectable in most of adult tissues, they are present in reproductive system such as testis, epididymis and ovary. This indicates a important role for Pem during embryogenesis and reproductive development. To study the function of mPem protein, we used a GAL4 based yeast two-hybrid assay to screen a 7-day mouse embryo library with full-length of mPem. 3 proteins were found interacting with mPem protein. One of theses is Mdfic. We confirmed the interaction between mPem and Mdfic in yeast and in vitro. Mdfic, MyoD family inhibitor domain containing, encodes the myoD family inhibitor domain (I-mfa domain). The interaction between mPem and Mdfic suggested they maybe form the transcriptional regulator complex to regulate embryo differentiation.

Interaction of mouse Pem protein and cell division cycle 37 homolog

Mouse Pem, a homeobox gene, encodes a protein consisting of 210 amino acid residues. To study the function of mouse Pem protein, we used the yeast two-hybrid system to screen the library of 7-day mouse embryo with full-length mouse Pem cDNA. Fifty-two colonies were obtained after 1.57 x 10(8) colonies were screened by nutrition limitation and beta-galactosidase assay. Seven individual insert fragments were obtained from the library, and three of them were identified, one of which was confirmed to be the cell division cycle 37 (Cdc37) homolog gene by sequencing. The interaction between mouse Pem and Cdc37 homolog was then confirmed by glutathione S-transferase pull-down assay, and the possible interaction model was suggested.

Modeling population genetic data in autotetraploid species

Allozyme and PCR-based molecular markers have been widely used to investigate genetic diversity and population genetic structure in autotetraploid species. However, an empirical but inaccurate approach was often used to infer marker genotype from the pattern and intensity of gel bands. Obviously, this introduces serious errors in prediction of the marker genotypes and severely biases the data analysis. This article developed a theoretical model to characterize genetic segregation of alleles at genetic marker loci in autotetraploid populations and a novel likelihood-based method to estimate the model parameters. The model properly accounts for segregation complexities due to multiple alleles and double reduction at autotetrasomic loci in natural populations, and the method takes appropriate account of incomplete marker phenotype information with respect to genotype due to multiple-dosage allele segregation at marker loci in tetraploids. The theoretical analyses were validated by making use of a computer simulation study and their utility is demonstrated by analyzing microsatellite marker data collected from two populations of sycamore maple (Acer pseudoplatanus L.), an economically important autotetraploid tree species. Numerical analyses based on simulation data indicate that the model parameters can be adequately estimated and double reduction is detected with good power using reasonable sample size.

Divergence Pattern of Duplicate Genes in Protein-Protein Interactions Follows the Power Law

The impact of the biological network structures on the divergence between the two copies of one duplicate gene pair involved in the networks has not been documented on a genome scale. Having analyzed the most recently updated Database of Interacting Proteins (DIP) by incorporating the information for duplicate genes of the same age in yeast, we find that there was a highly significantly positive correlation between the level of connectivity of ancient genes and the number of shared partners of their duplicates in the protein-protein interaction networks. This suggests that duplicate genes with a low ancestral connectivity tend to provide raw materials for functional novelty, whereas those duplicate genes with a high ancestral connectivity tend to create functional redundancy for a genome during the same evolutionary period. Moreover, the difference in the number of partners between two copies of a duplicate pair was found to follow a power-law distribution. This suggests that loss and gain of interacting partners for most duplicate genes with a lower level of ancestral connectivity is largely symmetrical, whereas the "hub duplicate genes" with a higher level of ancient connectivity display an asymmetrical divergence pattern in protein-protein interactions. Thus, it is clear that the protein-protein interaction network structures affect the divergence pattern of duplicate genes. Our findings also provide insights into the origin and development of biological networks.

An improved formulation of marker heterozygosity in recurrent selection and backcross schemes

This report presents a theoretical formulation for predicting heterozygosity of a putative marker locus linked to two quantitative trait loci (QTL) in a recurrent selection and backcross (RSB) scheme. Since the heterozygosity at any given marker locus maintained in such a breeding programme reflects its map location relative to QTL, the present study develops the theoretical analysis of the QTL mapping method that recently appeared in the literature. The formulae take into account selection, recombination and finite population size during the multiple-generation breeding scheme. The single-marker and two-QTL model was compared numerically with the model involving two linked marker loci and two QTL. Without recombination interference, the two models predict the same expected heterozygosity at the linked marker loci, indicating that the model is valid for predicting marker heterozygosity maintained at any loci in an RSB breeding scheme. The formulation is demonstrated numerically for several RSB schemes and its implications in developing a likelihood-based statistical framework for modeling the RSB experiments are discussed.

Theoretical basis for genetic linkage analysis in autotetraploid species

Linkage analysis in autotetraploid species has been an historical challenge in quantitative genetics theory and is a stumbling block that urgently needs to be removed in the rapidly emerging genome research on this species, such as cultivated potato. This article presents theory of a full model of tetrasomic linkage and develops a statistical framework for the linkage analysis. The model considers both double reduction and recombination, the most essential features of tetrasomic inheritance with linked loci, whereas the statistical method takes appropriate account of the major complexities in analyzing both dominant and codominant molecular marker data during map reconstruction in tetraploid species. These complexities include the problems arising from multiple dosage of allelic inheritance, the null allele, allelic segregation distortion, mixed bivalent and quadrivalent pairing in meiosis, and incomplete information of marker phenotype data. The theoretical analysis established the relationship between the coefficients of double reduction at linked loci, which is essential in the present tetrasomic linkage analysis and in assessing the impact of double reduction on the evolution of tetraploid populations. The statistical method, based on the combination of theoretical analysis and a computer-based algorithm, provided analytical tools for predicting the maximum-likelihood estimates of the model parameters. A simulation study showed the feasibility of a practical implementation of the method, detailed the procedure of the analysis, validated the power and reliability in the parameter estimation, and compared the present method with those proposed in the current literature.

Induced recovery of defective membrane expression of a CC chemokine receptor 5 mutant by phytohemagglutinin

CC chemokine receptor 5 (CCR5) is a member of the G-protein-coupled receptor superfamily. It plays an important role in macrophage tropic human immunodeficiency virus-1 entry and in some inflammatory reactions. CCR5-893(-) is a single-nucleotide deletion that results in complete truncation of the C tail of the gene product. We detected CCR5-893(-) in a sample of patients infected with non-tuberculosis mycobacteria and found that it was maintained heterozygously with a frequency of 2%. There is no association between this mutation and any immunodeficiency. Membrane expression of CCR5-893(-) was substantially reduced compared to the wild type, but this defective surface presentation recovered greatly recovered in the presence of 2 mg l(-1) phytohemagglutinin (PHA). However, PHA inducement did not affect the total intracellular expression of CCR5-893(-) or wild-type CCR5. Thus we suggest there exist some PHA-induced factor(s) that could mediate the presentation of truncated CCR5.

TetraploidMap: construction of a linkage map in autotetraploid species

TetraploidMap is a suite of Fortran 90 routines run from Microsoft Windows with a text-based input and output. TetraploidMap enables the user to assemble a linkage map from dominant and codominant (multiallelic) marker loci scored for the parents and full-sib progeny of a cross in an autotetraploid species. It includes routines for the inference of the parental genotypes, identification of linkage groups, two-point analysis to estimate the recombination frequency and LOD score between all pairs of marker in a linkage group, and locus ordering by simulated annealing.

Precision and high-resolution mapping of quantitative trait loci by use of recurrent selection, backcross or intercross schemes

Dissecting quantitative genetic variation into genes at the molecular level has been recognized as the greatest challenge facing geneticists in the twenty-first century. Tremendous efforts in the last two decades were invested to map a wide spectrum of quantitative genetic variation in nearly all important organisms onto their genome regions that may contain genes underlying the variation, but the candidate regions predicted so far are too coarse for accurate gene targeting. In this article, the recurrent selection and backcross (RSB) schemes were investigated theoretically and by simulation for their potential in mapping quantitative trait loci (QTL). In the RSB schemes, selection plays the role of maintaining the recipient genome in the vicinity of the QTL, which, at the same time, are rapidly narrowed down over multiple generations of backcrossing. With a high-density linkage map of DNA polymorphisms, the RSB approach has the potential of dissecting the complex genetic architecture of quantitative traits and enabling the underlying QTL to be mapped with the precision and resolution needed for their map-based cloning to be attempted. The factors affecting efficiency of the mapping method were investigated, suggesting guidelines under which experimental designs of the RSB schemes can be optimized. Comparison was made between the RSB schemes and the two popular QTL mapping methods, interval mapping and composite interval mapping, and showed that the scenario of genomic distribution of QTL that was unlocked by the RSB-based mapping method is qualitatively distinguished from those unlocked by the interval mapping-based methods.

Stability analysis and design of automatic frequency control system for in vivo EPR spectroscopy

Stability analysis and design of an automatic frequency control (AFC) system for in vivo continuous-wave EPR spectroscopy is described. The open-loop function of the feedback control system for the AFC was derived and the stability of the feedback loop systematically examined. A stability analysis of the system is demonstrated and a systematic design procedure is proposed. The design is started from the required system specifications (phase margin, steady-state error, and system bandwidth) and clear guidelines for designing an AFC system are given. A case study of the design is presented based on the specific needs of in vivo EPR measurements. A phase margin of 53 degrees, a steady-state error of 1.6%, and a system bandwidth of up to 1.8 kHz were obtained in the designed AFC system. The system specifications defined in advance are satisfied in this case study.

Modeling linkage disequilibrium between a polymorphic marker locus and a locus affecting complex dichotomous traits in natural populations

Linkage disequilibrium is an important topic in evolutionary and population genetics. An issue yet to be settled is the theory required to extend the linkage disequilibrium analysis to complex traits. In this study, we present theoretical analysis and methods for detecting or estimating linkage disequilibrium (LD) between a polymorphic marker locus and any one of the loci affecting a complex dichotomous trait on the basis of samples randomly or selectively collected from natural populations. Statistical properties of these methods were investigated and their powers were compared analytically or by use of Monte Carlo simulations. The results show that the disequilibrium may be detected with a power of 80% by using phenotypic records and marker genotype when both the trait and marker variants are common (30%) and the LD is relatively high (40-100% of the theoretical maximum). The maximum-likelihood approach provides accurate estimates of the model parameters as well as detection of linkage disequilibrium. The likelihood method is preferred for its higher power and reliability in parameter estimation. The approaches developed in this article are also compared to those for analyzing a continuously distributed quantitative trait. It is shown that a larger sample size is required for the dichotomous trait model to obtain the same level of power in detecting linkage disequilibrium as the continuous trait analysis. Potential use of these estimates in mapping the trait locus is also discussed.

Construction of a genetic linkage map in tetraploid species using molecular markers

This article presents methodology for the construction of a linkage map in an autotetraploid species, using either codominant or dominant molecular markers scored on two parents and their full-sib progeny. The steps of the analysis are as follows: identification of parental genotypes from the parental and offspring phenotypes; testing for independent segregation of markers; partition of markers into linkage groups using cluster analysis; maximum-likelihood estimation of the phase, recombination frequency, and LOD score for all pairs of markers in the same linkage group using the EM algorithm; ordering the markers and estimating distances between them; and reconstructing their linkage phases. The information from different marker configurations about the recombination frequency is examined and found to vary considerably, depending on the number of different alleles, the number of alleles shared by the parents, and the phase of the markers. The methods are applied to a simulated data set and to a small set of SSR and AFLP markers scored in a full-sib population of tetraploid potato.

[Metallic stents for malignant esophageal neoplasms stenosis in advanced stage]

Maligant esophageal stenosis affects the qulity of the patients' life severely. Self-Expanding Metallic Stent (SEMS) can relieve the patient from dysphagia. In this article, we summarized the application and clinical complication of SEMS in maligant esophageal stenosis.

Inferring linkage disequilibrium between a polymorphic marker locus and a trait locus in natural populations

Three approaches are proposed in this study for detecting or estimating linkage disequilibrium between a polymorphic marker locus and a locus affecting quantitative genetic variation using the sample from random mating populations. It is shown that the disequilibrium over a wide range of circumstances may be detected with a power of 80% by using phenotypic records and marker genotypes of a few hundred individuals. Comparison of ANOVA and regression methods in this article to the transmission disequilibrium test (TDT) shows that, given the genetic variance explained by the trait locus, the power of TDT depends on the trait allele frequency, whereas the power of ANOVA and regression analyses is relatively independent from the allelic frequency. The TDT method is more powerful when the trait allele frequency is low, but much less powerful when it is high. The likelihood analysis provides reliable estimation of the model parameters when the QTL variance is at least 10% of the phenotypic variance and the sample size of a few hundred is used. Potential use of these estimates in mapping the trait locus is also discussed.

Anatomical and neurochemical peculiarities of the pika retina: basis for lack of circadian rhythm of core temperature

We have previously reported a complete lack of circadian rhythm in the body temperature of pikas in contrast to other lagomorphs. In this present study, the anatomical and neurochemical findings by immunohistochemical, photo and electron microscopic methods reveal that the photoreceptor system of this animal is poorly developed. This probably explains their stable core body temperature which help them survive in cold temperatures.