Bibliometric analysis of myelin imaging studies of patients with multiple sclerosis (2000-2022)

Background

Multiple sclerosis (MS) is a condition that can impact the central nervous system (CNS) and cause damage to the myelin, which is responsible for facilitating the normal transmission of electrical impulses along the nerves. We performed a bibliometric analysis of the scientific publications on myelin imaging in MS to reveal the development trends in this field and to evaluate research trends in myelin imaging in MS.

Methods

The Web of Science Core Collection was searched for articles related to myelin imaging in MS published between January 2000 and December 2022. CiteSpace, VOSviewer, and R language were used to evaluate and visualize contributions by and co-occurrence relationships among countries and institutions, authors, journals, citations, keywords, and so on.

Results

A total of 1,639 articles addressed the topic of myelin imaging in MS. The United States had the largest number of annual publications. The University of London was the institution with the highest number of publications (n=118) and citations (n=9,885). The top 3 productive authors were all from the University of British Columbia in Canada. An article published by Mackay et al. in 1994 had the most citations (n=272). Neuroimage [impact factor (IF) =7.40, Journal Citation Reports quartile 1 (Q1)] was the most productive journal in terms of the number of articles relating to myelin imaging in MS (n=149). In recent years, myelin water imaging, synthetic magnetic resonance imaging (SyMRI), inhomogeneous magnetization, positron emission tomography (PET) imaging, and aquaporin-4 (AQP4) have been researched hotspots of myelin imaging in MS.

Conclusions

With advancements in the pathophysiological research on myelin changes in MS, myelin imaging is playing an important role in the diagnosis and treatment of MS. In addition, the use of new sequences of myelin imaging to distinguish MS from other inflammatory demyelinating diseases is a future development trend in this field.

Preparation of polyvinyl alcohol/chitosan nanofibrous films incorporating graphene oxide and lanthanum chloride by electrospinning method for potential photothermal and chemical synergistic antibacterial applications in wound dressings

Electrospun fibres have been widely used as skin dressings due to their unique structur. However, due to the lack of intrinsic antimicrobial activity, it is easy for the wound to become infected. Bacterial infection, which leads to chronic inflammation, severely hinders the normal process of skin regeneration. In this study, a polyvinyl alcohol/chitosan (PVA/CS) composite films with chemical sterilization and near-infrared (NIR) photothermal antibacterial activity was fabricated by electrospinning. Graphene oxide (GO), a photosensitiser, was incorporated into the films, and lanthanum chloride (Lacl3) as a chemical antibacterial agent was also doped in the electrospun films. The structure, morphology, mechanical properties, wettability, and antimicrobial and photothermal antibacterial activity of the PVA/CS-based fibre films were investigated. The results showed that the addition of Lacl3 to the PVA/CS/GO nanofibres (PVA/CS/GO-La) improved the hydrophilicity, tensile strength and resistance to elastic deformation of the nanofibres. The PVA/CS/GO-La12.5 mM sample exhibited the best antibacterial performance, showing high inhibition against Staphylococcus aureus (82% antibacterial efficacy) and Escherichia coli (99.7% antibacterial efficacy). Furthermore, the antibacterial efficacy of the films surface was further enhanced after exposure to NIR light (808 nm, 0.01 W) for 20 min. In addition, the nanofibre films showed no cytotoxicity against human skin fibroblasts (HSFs), indicating its potential application in the field of broad-spectrum antibacterial materials.

Quantitative association of cerebral blood flow, relaxation times and proton density in young and middle-aged primary insomnia patients: A prospective study using three-dimensional arterial spin labeling and synthetic magnetic resonance imaging

Objectives

To quantitatively measure the T1 value, T2 value, proton density (PD) value, and cerebral blood flow (CBF) in young and middle-aged primary insomnia (PI) patients, and analyze the correlations between relaxation times, PD, and CBF to explore potential brain changes.

Methods

Cranial magnetic resonance (MR) images of 44 PI patients and 30 healthy subjects were prospectively collected for analysis. The T1, T2, PD, and CBF values of the frontal lobe, parietal lobe, temporal lobe, and occipital lobe were independently measured using three-dimensional arterial spin labeling (3D-ASL), synthetic magnetic resonance imaging (syMRI) and a whole-brain automatic segmentation method. The differences of these imaging indices were compared between PI patients and healthy subjects. Follow-up MR images were obtained from PI patients after 6 months to compare with pre-treatment images. The Wilcoxon signed rank test and Spearman rank were used for statistical analysis.

Results

Bilateral CBF asymmetry was observed in 38 patients, with significant differences in both the T2 value and CBF between the four lobes of the brain (p < 0.01). However, no significant difference was found in the T1 and PD values between the bilateral lobes. A negative correlation was found between CBF and T2 values in the right four lobes of patients with primary insomnia (PI). During follow-up examinations, five PI patients showed a disappearance of insomnia symptoms and a decrease in CBF in both brain lobes.

Conclusion

Insomnia symptoms may be associated with high CBF, and most PI patients have higher CBF and lower T2 values in the right cerebral hemispheres. The right hemisphere appears to play a critical role in the pathophysiology of PI. The 3D-ASL and syMRI technologies can provide a quantitative imaging basis for investigating the brain conditions and changes in young and middle-aged PI patients.

Evaluation of the Effects of Anti-PD-1 Therapy on Triple-Negative Breast Cancer in Mice by Diffusion Kurtosis Imaging and Dynamic Contrast-Enhanced Imaging

BACKGROUND

The monitoring of immunotherapies is still based on changes in the tumor size in imaging, with a long evaluation period and low sensitivity.

PURPOSE

To investigate the effectiveness of diffusion kurtosis imaging (DKI) and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in assessing the therapeutic efficacy of anti-programmed death-1 (PD-1) therapy in a mouse triple negative breast cancer (TNBC) model.

STUDY TYPE

Prospective.

ANIMAL MODEL

A total of 54 BALB/c mouse subcutaneous 4 T1 transplantation models of TNBC.

FIELD STRENGTH/SEQUENCE

A 3.0-T; turbo spin echo (TSE) T2-weighted imaging, DKI with seven b values (0, 500, 1000, 1500, 2000, 2500, and 3000 sec/mm² ) and T1-twist DCE acquisition series.

ASSESSMENT

DKI and DCE-MRI parameters were evaluated by two radiologists independently. Regions of interest (ROIs) were drawn manually on the maximum cross-sectional area of the lesion; care was taken to avoid necrotic areas. The tumor cell density, the CD45 and CD31 levels were analyzed by two pathologists.

STATISTICAL TESTS

The two-tailed unpaired t-test, Mann-Whitney U test, Fisher's exact test and Pearson correlation coefficient were performed. A P < 0.05 was considered statistically significant.

RESULTS

The apparent diffusion coefficient (ADC), mean diffusivity (MD), K_trans and K_ep values were significantly different between the two groups at each time point after treatment. There were significant differences in the mean kurtosis (MK) and V_e values between the two groups at 5 and 10 days after treatment but no significant differences at 15 days (P = 0.317 and 0.183, respectively). The ADC and MD values were significantly correlated with tumor cell density (ADC, r = -0.833; MD, r = 0.890) and the CD45 level (ADC, r = 0.720; MD, r = 0.718). The K_trans and K_ep values were significantly correlated with the CD31 level (K_trans , r = 0.820; K_ep , r = 0.683).

DATA CONCLUSION

DKI and DCE-MRI could reflect the changes in tumor microstructure and tumor tissue vasculature after anti-PD-1 therapy, respectively.

LEVEL OF EVIDENCE

1 TECHNICAL EFFICACY: Stage 4.

[Efficacy and safety of daratumumab in patients with relapsed/refractory multiple myeloma]

Objective: To investigate the efficacy and safety of daratumumab in relapsed/refractory multiple myeloma (RRMM) patients. Methods: Fifty-two RRMM patients treated with daratumumab from September 2019 to November 2021 in West China Hospital were retrospectively enrolled, including 31 males and 21 females. The mean age of these patients at the first diagnosis of multiple myeloma was (58±10) years. According to the dosage of daratumumab, patients were divided into low dosage group (n=10) and high dosage group (n=42). Overall response rate (ORR), progression-free survival (PFS), overall survival (OS), and adverse event rates were investigated. Univariate and multivariate analysis of potential factors were conducted. Results: Of the 52 patients, 8 received daratumumab monotherapy, 27 received daratumumab plus immuno-modulatory drug (IMiD) treatment, 4 received daratumumab plus proteosome inhibitor (PI) treatment, and 11 received daratumumab plus dexamethasone treatment. The diagnosis age of high dosage group patients was (57±9) years, which was significantly younger than that of low dosage group [(66±10) years] (P=0.009). The baseline creatinine level of high dosage group patients [M (Q₁, Q₃)] was 91 (68, 196) μmol/L, which was significantly higher than that of low dosage group [66 (51, 76) μmol/L] (P=0.021). There was no significant difference in other baseline clinical characteristics, previous treatment regimens, previous lines of treatment, and regimen and cycles of daratumumab between the high dosage group and low dosage group (all P>0.05). The ORR for the 52 patients was 71.2% (37/52). The ORR for daratumumab plus IMiD group was 81.5% (22/27), which was significantly higher than that in monotherapy or dexamethasone group [ORR: 52.6% (10/19), P=0.036). With a median follow-up [M (Q₁, Q₃)] of 7 (5, 26) months, the median PFS for overall cohort was 17 (95%CI: 9.6-24.4) months. The median PFS for daratumumab plus IMiD group was 26 (95%CI: 6.0-46.0) months, which was significantly better than that in monotherapy or dexamethasone group [12 (95%CI: 3.5-20.5) months] (HR=0.231, 95%CI: 0.075-0.715, P=0.011). Higher diagnosis age was the risk factor of progression (HR=1.085, 95%CI: 1.016-1.158, P=0.014), while more cycles of daratumumab treatment was the protective factor of progression (HR=0.669, 95%CI: 0.495-0.904, P=0.009). There was no significant influence of daratumumab dosage on progression (high dosage vs low dosage, HR=1.016, 95%CI: 0.221-4.668, P=0.984). The median OS for overall cohort was 26 (95%CI: 13.1-38.9) months. Higher serum calcium was the independent risk factor of death (HR=12.190, 95%CI: 1.170-127.048, P=0.037). There was no significant influence of daratumumab dosage on death (high dosage vs low dosage, HR=0.818, 95%CI: 0.171-3.917, P=0.802). Adverse events included infections (43.2%, 16/37), infusion-associated reactions (29.7%, 11/37), and thrombocytopenia (27.0%, 10/37). Conclusions: Daratumumab is effective to treat RRMM. The dosage of daratumumab has no significant influence on prognosis when used in combined treatment. The incidence of adverse events is relatively low, with a favorable safety profile.

Influence of continuing nursing care team mode on the rehabilitation of patients with pancreatic cancer after postoperative daily chemotherapy

OBJECTIVE

This study aimed to investigate the effect of continuing nursing care team mode on postoperative outpatient chemotherapy patients with pancreatic cancer.

METHODS

One-hundred patients receiving postoperative outpatient chemotherapy for pancreatic cancer between September 2019 and December 2020 were enrolled in this study and divided into two groups, an intervention group and a control group (n = 50 each), by random number table method or coin tossing method. The patients in the intervention group were followed up using continuing nursing care team mode, while those in the control group were followed up using the traditional telephone follow-up mode. The effects of the two modes on patients' self-care ability, quality of life, anxiety, hospital waiting time, and the nurses' communication ability and self-efficacy were compared and analyzed.

RESULTS

The self-care ability and quality of life of the patients in the intervention group were better than those of the control group (p < 0.05), the anxiety score and hospital waiting times were lower than those in the control group (p < 0.05), and the communication ability and general self-efficacy of the nurses were also significantly stronger than those in the control group (p < 0.05).

CONCLUSION

The application of the continuing nursing care team mode for follow-up can improve the self-care ability and quality of life of patients, effectively reduce the anxiety and hospital waiting time of outpatient chemotherapy patients, and improve the nurses' communication ability and general self-efficacy. Therefore, this practice is worthy of clinical popularization.

Multichannel Distribution and Transformation of Entangled Photons with Dielectric Metasurfaces

Photonic quantum information processing relies on operating the quantum state of photons, which usually involves bulky optical components unfavorable for system miniaturization and integration. Here, we report on the transformation and distribution of polarization-entangled photon pairs with multichannel dielectric metasurfaces. The entangled photon pairs interact with metasurface building blocks, where the geometrical-scaling-induced phase gradients are imposed, and are transformed into two-photon entangled states with the desired polarization. Two metasurfaces, each simultaneously distributing polarization-entangled photons to spatially separated multiple channels M (N), may accomplish M×N channels of entanglement distribution and transformation. Experimentally we demonstrate 2×2 and 4×4 distributed entanglement states, including Bell states and superposition of Bell states, with high fidelity and strong polarization correlation. We expect this approach paves the way for future integration of quantum information networks.

Hydrogen inhalation promotes recovery of a patient in persistent vegetative state from intracerebral hemorrhage: A case report and literature review

BACKGROUND

Persistent vegetative state (PVS) is a devastating and long-lasting clinical condition with high morbidity and mortality; currently, there are no available effective interventions.

CASE SUMMARY

We report the case of an 11-year-old boy with PVS caused by severe intracerebral bleeding in the left hemisphere following anticoagulation treatment. The patient’s PVS severity showed no notable improvement after 2-mo neuroprotective treatment and rehabilitation, including nerve growth factor and baclofen, hyperbaric oxygen, and comprehensive bedside rehabilitation therapies. Daily inhalation treatment (4-6 h) of high-concentration hydrogen (H₂) gas (66.6% H₂ + 33.3% O₂) was provided. Surprisingly, the patient’s orientation, consciousness, ability to speak, facial expressions, and locomotor function were significantly restored, along with improvements in essential general health status, after H₂ gas inhalation treatment, which was consistent with stabilized neuropathology in the left hemisphere and increased Hounsfield unit values of computed tomography in the right hemisphere. The patient finally recovered to a near normal conscious state with a Coma Recovery Scale-Revised Score of 22 from his previous score of 3.

CONCLUSION

Phase 1 clinical trials are needed to explore the safety and efficacy of H₂ gas inhalation in patients with PVS.

Performance of radiomics models for tumour-infiltrating lymphocyte (TIL) prediction in breast cancer: the role of the dynamic contrast-enhanced (DCE) MRI phase

OBJECTIVE

To systematically investigate the effect of imaging features at different DCE-MRI phases to optimise a radiomics model based on DCE-MRI for the prediction of tumour-infiltrating lymphocyte (TIL) levels in breast cancer.

MATERIALS AND METHODS

This study retrospectively collected 133 patients with pathologically proven breast cancer, including 73 patients with low TIL levels and 60 patients with high TIL levels. The volumes of breast cancer lesions were manually delineated on T2-weighted imaging (T2WI), diffusion-weighted imaging (DWI), and each phase of DCE-MRI, followed by 6250 quantitative feature extractions. The least absolute shrinkage and selection operator (LASSO) method was used to select predictive feature sets for the classifiers. Four models were developed for predicting TILs: (1) single enhanced phase radiomics models; (2) fusion enhanced multi-phase radiomics models; (3) fusion multi-sequence radiomics models; and (4) a combined radiomics-based clinical model.

RESULTS

Image features extracted from the delayed phase MRI, especially DCE_Phase 6 (DCE_P6), demonstrated dominant predictive performances over features from other phases. The fusion multi-sequence radiomics model and combined radiomics-based clinical model achieved the highest predictive performances with areas under the curve (AUCs) of 0.934 and 0.950, respectively; however, the differences were not statistically significant.

CONCLUSION

The DCE-MRI radiomics model, especially image features extracted from the delayed phases, can help improve the performance in predicting TILs. The radiomics nomogram is effective in predicting TILs in breast cancer.

KEY POINTS

• Radiomics features extracted from DCE-MRI, especially delayed phase images, help predict TIL levels in breast cancer. • We developed a nomogram based on MRI to predict TILs in breast cancer that achieved the highest AUC of 0.950.

Comparison of poststroke depression between acute ischemic and hemorrhagic stroke patients

OBJECTIVES

Depression is the most common mental complication in stroke survivors with about one-third of patients suffering from poststroke depression (PSD). This was the first prospective study aimed to compare the prevalence of PSD and its symptoms between two cohorts of patients with acute ischemic stroke (AIS) and intracerebral hemorrhage (ICH).

METHODS

Both AIS and ICH patients were simultaneously enrolled in the study. Depression symptoms were measured using the 17-item Hamilton Depression Rating Scale (HAMD-17) after a 1-month follow-up. Patients were diagnosed with PSD according to the Diagnostic and Statistical Manual of Mental Disorders, fourth edition and the HAMD-17 (HAMD scores >7).

RESULTS

The prevalence of PSD (42.3%) in the ICH group was significantly higher than that (22.9%) in the AIS group (p < 0.001). After adjustment for conventional confounding factors, the odds ratio of PSD was 2.65 (95% CI, 1.34-5.24, p = 0.005) for ICH compared to AIS. Depressive symptoms consisting of anxiety, loss of interest, insomnia, and fatigue were more frequent in patients with ICH than in AIS patients.

CONCLUSIONS

PSD was more prevalent, and the risk was over twofold higher in patients with ICH than AIS.

Whole-Lesion Histogram Analysis of the Apparent Diffusion Coefficient as a Quantitative Imaging Biomarker for Assessing the Level of Tumor-Infiltrating Lymphocytes: Value in Molecular Subtypes of Breast Cancer

Purpose

To assess whether apparent diffusion coefficient (ADC) metrics can be used to assess tumor-infiltrating lymphocyte (TIL) levels in breast cancer, particularly in the molecular subtypes of breast cancer.

Methods

In total, 114 patients with breast cancer met the inclusion criteria (mean age: 52 years; range: 29–85 years) and underwent multi-parametric breast magnetic resonance imaging (MRI). The patients were imaged by diffusion-weighted (DW)-MRI (1.5 T) using a single-shot spin-echo echo-planar imaging sequence. Two readers independently drew a region of interest (ROI) on the ADC maps of the whole tumor. The mean ADC and histogram parameters (10^th, 25^th, 50^th, 75^th, and 90^th percentiles of ADC, skewness, entropy, and kurtosis) were used as features to analyze associations with the TIL levels in breast cancer. Additionally, the correlation between the ADC values and Ki-67 expression were analyzed. Continuous variables were compared with Student’s t-test or Mann-Whitney U test if the variables were not normally distributed. Categorical variables were compared using Pearson’s chi-square test or Fisher’s exact test. Associations between TIL levels and imaging features were evaluated by the Mann-Whitney U and Kruskal-Wallis tests.

Results

A statistically significant difference existed in the 10^th and 25^th percentile ADC values between the low and high TIL groups in breast cancer (P=0.012 and 0.027). For the luminal subtype of breast cancer, the 10^th percentile ADC value was significantly lower in the low TIL group (P=0.041); for the non-luminal subtype of breast cancer, the kurtosis was significantly lower in the low TIL group (P=0.023). The Ki-67 index showed statistical significance for evaluating the TIL levels in breast cancer (P=0.007). Additionally, the skewness was significantly higher for samples with high Ki-67 levels in breast cancer (P=0.029).

Conclusions

Our findings suggest that whole-lesion ADC histogram parameters can be used as surrogate biomarkers to evaluate TIL levels in molecular subtypes of breast cancer.

Cardiac parameters affect prognosis in patients with non-large atherosclerotic infarction

Background

Although large artery atherosclerosis (LAA) is the most common type of cerebral infarction, non-LAA is not uncommon. The purpose of this paper is to investigate the prognosis of patients with non-LAA and to establish a corresponding nomogram.

Patients and methods

Between June 2016 and June 2017, we had 1101 admissions for acute ischemic stroke (AIS). Of these, 848 were LAA and 253 were non-LAA. Patients were followed up every 3 months with a minimum of 1 year of follow-up. After excluding patients who were lost follow-up and patients who did not meet the inclusion criteria, a total of 152 non-LAA patients were included in this cohort study. After single-factor analysis and multifactor logistic regression analysis, the risk factors associated with prognosis were derived and different nomograms were developed based on these risk factors. After comparison, the best model is derived.

Results

Logistics regression found that the patient’s National Institutes of Health Stroke Scale (NIHSS) score, ejection fraction (EF), creatine kinase-MB (CK-MB), age, neutrophil-to-lymphocyte ratio (NLR), aspartate aminotransferase (AST), and serum albumin were independently related to the patient’s prognosis. We thus developed three models: model 1: single NIHSS score, AUC = 0.8534; model 2, NIHSS + cardiac parameters (CK-MB, EF), AUC = 0.9325; model 3, NIHSS + CK−MB + EF + age + AST + NLR + albumin, AUC = 0.9598. We compare the three models: model 1 vs model 2, z = − 2.85, p = 0.004; model 2 vs model 3, z = − 1.58, p = 0.122. Therefore, model 2 is considered to be the accurate and convenient model.

Conclusions

Predicting the prognosis of patients with non-LAA is important, and our nomogram, built on the NIHSS and cardiac parameters, can predict the prognosis accurately and provide a powerful reference for clinical decision making.

Early-Onset Depression in Stroke Patients: Effects on Unfavorable Outcome 5 Years Post-stroke

Background: Post-stroke depression (PSD) constitutes an essential complication of stroke and is associated with high-risk unfavorable outcome after stroke. The main objective of this prospective study was to determine the relationship between early-onset PSD (1 month after stroke) and functional outcomes 5 years after baseline enrollment. Methods: Four hundred thirty-six patients who met the criteria were included in this study from October 2013 to February 2015. The follow-up time for each patient was ~5 years, with follow-up every 3 months. Patients received questionnaires including the 17-item Hamilton Depression Scale (HAMD), the Mini-Mental State Examination (MMSE), the National Institutes of Health Stroke Scale (NIHSS), the modified Rankin Scale (mRS), and the Barthel Index (BI). Results: Of the 436 patients, 154 (35.3%) patients with the prevalence of PSD status at baseline, 26 (7.2%) patients with the prevalence of PSD status, and 73 (20.1%) had an unfavorable outcome 5 years after stroke. The odds ratio (OR) for unfavorable outcome at 5 years in the PSD group was ~2.2 relative to the non-PSD group after adjusting for potential risk factors [OR = 2.217, 95% confidence interval (CI) = 1.179-4.421, P = 0.015]. In the early-onset PSD group, HAMD scores were independently associated with 5-year unfavorable outcome rates (OR = 1.168, 95% CI = 1.015-1.345, P = 0.031). Conclusions: Our findings indicate that early-onset PSD status in Chinese patients is an independent risk factor for unfavorable outcome 5 years after stroke, and that the severity of PSD is also related to unfavorable outcome.

Corrigendum: Early-Onset Depression in Stroke Patients: Effects on Unfavorable Outcome 5 Years Post-stroke

[This corrects the article DOI: 10.3389/fpsyt.2021.556981.].

Magnetic Resonance Imaging (MRI) Phenotypes May Provide Additional Information for Risk Stratification for Encapsulated Papillary Carcinoma of the Breast

Background

Encapsulated papillary carcinoma (EPC) of the breast is a rare entity. EPC can be underappreciated on percutaneous biopsy, which may require additional procedures if invasion is not recognized preoperatively. We aimed to investigate the magnetic resonance imaging (MRI) phenotypes correlated with preoperative pathological risk stratification for clinical guidance.

Materials and Methods

The preoperative MRI scans of 30 patients diagnosed with 36 EPCs in multiple centers between August 2015 and February 2020 were reviewed by two breast radiologists. According to the WHO classification published in 2019, EPCs were classified into two pathological subtypes: encapsulated papillary carcinoma and encapsulated papillary carcinoma with invasion. Clinicopathological analysis of the two subtypes and MR feature analysis were performed.

Results

Evaluation of the MRI phenotypes and pathological subtype information revealed that not circumscribed (P=0.04) was more common in EPCs with invasion than in EPCs. There was a significant difference in the age of patients (P=0.05), and the risk increased with age. The maximum diameter of the tumor increased with tumor risk, but there was no significant difference (P=0.36). Nearly half of the EPC with invasion patients showed hyperintensity on T1WI (P=0.19). A total of 63.6% of the EPC with invasion group showed non-mass enhancement surrounding (P=0.85). In addition, 29 patients (96.7%) had no axillary lymph node metastasis, and only one patient with EPC with invasion had axillary lymph node metastasis. Further pathological information analysis of EPCs showed that higher Ki-67 levels were more common in patients with EPCs with invasion (P=0.04). A total of 29 patients (96.7%) had the luminal phenotype, and one patient with EPC with invasion had the Her-2-positive phenotype.

Conclusion

The margin, age and Ki-67 level were the key features for EPC risk stratification. In addition, these MRI signs, including a larger tumor, non-mass enhancement surrounding and axillary lymph node metastasis, may be suggestive of a high-risk stratification. Therefore, MRI phenotypes may provide additional information for the risk stratification of EPCs.

A high neutrophil-to-lymphocyte ratio predicts hemorrhagic transformation of large atherosclerotic infarction in patients with acute ischemic stroke

Increasing evidence suggests that inflammation is associated with the development of acute ischemic stroke (AIS). The neutrophil-to-lymphocyte ratio (N/L) is an important marker of inflammation and is highly correlated with mortality in stroke patients in recent studies. The N/L of patients who experience hemorrhagic transformation (HT) after AIS is know, but any relationship between N/L and large artery atherosclerosis (LAA) remains unclear, this is our present topic. We enrolled 185 patients with LAA-type HT in the development cohort from a prospective, consecutive, hospital-based stroke registry to this end. We matched these patients to 213 LAA patients who did not develop HT as controls. The incidence of HT after LAA was significantly greater (P<0.01) in patients with higher N/L. We developed a predictive nomogram (incorporating age, systolic blood pressure, the National Institutes of Health Stroke Scale, and the N/L) for LAA patients. The predictive power was good (area under the curve, AUC: 0.832, 95%CI: 0.791–0.872). Our findings were further validated in a validation cohort of 202 patients with AIS attributable to LAA (AUC:0.836, 95%CI:0.781–0.891). In summary, a high N/L is associated with an increased risk for HT after LAA.

Cobalt disulfide-modified cellular hierarchical porous carbon derived from bovine bone for application in high-performance lithium-sulfur batteries

Improving the insulating nature of sulfur and retaining the soluble polysulfides in sulfur cathodes are crucial for realizing the practical application of lithium-sulfur batteries (LSBs). Biomass-based carbon is becoming increasingly popular for fabricating economical and efficient cathodes for LSBs owing to its unique structure. Herein, we report a facile strategy to transform bovine bone with an organic-inorganic structure into cellular hierarchical porous carbon via carbonization and KOH activation, followed by CoS₂ modification through hydrothermal treatment. The synthesized composite can load abundant sulfur and produce a dual effect of "physical confinement and chemical entrapment" on polysulfides. The conductive carbon frame with the developed porous structure provides adequate space to accommodate sulfur and physically suppress the shuttle effect of polysulfides. The embedded half-metallic CoS₂ sites can chemically anchor the polysulfides and enhance the electrochemical reaction activity as well. Owing to the multifunctional structure and dual restraint effect, the designed electrode exhibits enhanced electrochemical properties including high initial capacity (1230.9 mAh g^-1 at 0.2 C), improved cycling stability and enhanced rate capability.

[Clinical and immunological analysis of patients with activated phosphoinositide 3-kinase δ syndrome resulting from PIK3CD mutation]

Objective: To explore the clinical and immunological features, gene mutations, treatment and prognosis in patients with activated phosphoinositide 3-kinase δ syndrome (APDS) caused by PIK3CD gene heterozygous germline mutation. Method: The data of clinical, immunological phenotype, treatment, and prognosis of 15 patients with APDS, who visited Children's Hospital of Chongqing Medical University, Peking Union Medical College Hospital, and Shenzhen Children's Hospital from June 2014 to November 2016, were collected and analyzed. Result: Of the 15 patients, 11 were males, remaining 4 patients were females. The median age of disease onset was 1 year, and median age at diagnosis was 4 years and 4 months. All patients had the de novo heterozygous germline mutation in PIK3CD (c. 3061G>A, p. E1021K). The common initial symptoms were respiratory infections, including pneumonia (12 cases) , bronchiectasis (5 cases). Other common clinical manifestations were recurrent and chronic diarrhea (11 cases), Epstein-Barr virus (EBV) and/or cytomegalovirus (CMV) viremia (10 cases), hepatosplenomegaly (13 cases), and lymphadenopathy (10 cases). The main immunological features were increased IgM (11 cases), decreased IgG (6 cases), decreased numbers of CD4⁺ T cell (7 cases) especially naïve CD4⁺ T cell (9 cases), reduced numbers of B cells (11 cases) particularly naïve B cells (9 cases), increased numbers of transitional B cells (5 cases) and CD8⁺ terminally differentiated effector memory T cells (5 cases). After 1-29 months follow up, 13 of the 15 cases remain survived, of whom 5 cases received regular intravenous immunoglobulin (IVIG) therapy, with reduced frequency of infections and improved severity of infections; of whom 3 cases received oral rapamycin therapy at the dosage of 1 mg/ (m²·d) and with a decrease in nonneoplastic lymphoproliferation. Conclusion: E1021K is a hotspot for mutation in the PIK3CD gene in patients with APDS. Regular IVIG can improve their quality of life. Targetel treatment with rapamycin could mitigate hepatosplenomegaly.

Whole-lesion histogram analysis of the apparent diffusion coefficient: Evaluation of the correlation with subtypes of mucinous breast carcinoma

PURPOSE

To evaluate the utility of the whole-lesion histogram apparent diffusion coefficient (ADC) for characterizing the heterogeneity of mucinous breast carcinoma (MBC) and to determine which ADC metrics may help to best differentiate subtypes of MBC.

MATERIALS AND METHODS

This retrospective study involved 52 MBC patients, including 37 pure MBC (PMBC) and 15 mixed MBC (MMBC). The PMBC patients were subtyped into PMBC-A (20 cases) and PMBC-B (17 cases) groups. All patients underwent preoperative diffusion-weighted imaging (DWI) at 1.5T and the whole-lesion ADC assessments were generated. Histogram-derived ADC parameters were compared between PMBC vs. MMBC and PMBC-A vs. PMBC-B, and receiver operating characteristic (ROC) curve analysis was used to determine optimal histogram parameters for differentiating these groups.

RESULTS

The PMBC group exhibited significantly higher ADC values for the mean (P = 0.004), 25^th (P = 0.004), 50^th (P = 0.004), 75^th (P = 0.006), and 90^th percentiles (P = 0.013) and skewness (P = 0.021) than did the MMBC group. The 25^th percentile of ADC values achieved the highest area under the curve (AUC) (0.792), with a cutoff value of 1.345 × 10^-3 mm² /s, in distinguishing PMBC and MMBC. The PMBC-A group showed significantly higher ADC values for the mean (P = 0.049), 25^th (P = 0.015), and 50^th (P = 0.026) percentiles and skewness (P = 0.004) than did the PMBC-B group. The 25^th percentile of the ADC cutoff value (1.476 × 10^-3 mm² /s) demonstrated the best AUC (0.837) among the ADC values for distinguishing PMBC-A and PMBC-B.

CONCLUSION

Whole-lesion ADC histogram analysis enables comprehensive evaluation of an MBC in its entirety and differentiating subtypes of MBC. Thus, it may be a helpful and supportive tool for conventional MRI.

LEVEL OF EVIDENCE

4 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018;47:391-400.

Lower eyelid reconstruction following a traumatic full thickness loss

Eyelid reconstruction is complex and challenging since it is not only for structural and functional restoration, but also for an acceptable aesthetic result. In full thickness eyelid injuries, it will involve both anterior and posterior lamella. Therefore, when reconstructing the defect, it requires at least two layers; one will be a flap with blood supply, and the other can be a free graft. In this case, a rotational advancement cheek flap and composite graft were used to reconstruct the lower eyelid.

Bioreducible amphiphilic block copolymers based on PCL and glycopolypeptide as multifunctional theranostic nanocarriers for drug delivery and MR imaging

Amphiphilic diblock poly(ε-caprolactone)-b-glycopolypeptides (PCL–SS–GPPs) bearing disulfide bonds were synthesized from a clickable poly(ε-caprolactone)–SS–poly(2-azidoethyl-l-glutamate) diblock copolymer.

Hyaluronan-modified superparamagnetic iron oxide nanoparticles for bimodal breast cancer imaging and photothermal therapy

Theranostic nanoparticles with both imaging and therapeutic abilities are highly promising in successful diagnosis and treatment of the most devastating cancers. In this study, the dual-modal imaging and photothermal effect of hyaluronan (HA)-modified superparamagnetic iron oxide nanoparticles (HA-SPIONs), which was developed in a previous study, were investigated for CD44 HA receptor-overexpressing breast cancer in both in vitro and in vivo experiments. Heat is found to be rapidly generated by near-infrared laser range irradiation of HA-SPIONs. When incubated with CD44 HA receptor-overexpressing MDA-MB-231 cells in vitro, HA-SPIONs exhibited significant specific cellular uptake and specific accumulation confirmed by Prussian blue staining. The in vitro and in vivo results of magnetic resonance imaging and photothermal ablation demonstrated that HA-SPIONs exhibited significant negative contrast enhancement on T2-weighted magnetic resonance imaging and photothermal effect targeted CD44 HA receptor-overexpressing breast cancer. All these results indicated that HA-SPIONs have great potential for effective diagnosis and treatment of cancer.

Construction of Epidermal Growth Factor Receptor Peptide Magnetic Nanovesicles with Lipid Bilayers for Enhanced Capture of Liver Cancer Circulating Tumor Cells

Highly effective targeted tumor recognition via vectors is crucial for cancer detection. In contrast to antibodies and proteins, peptides are direct targeting ligands with a low molecular weight. In the present study, a peptide magnetic nanovector platform containing a lipid bilayer was designed using a peptide amphiphile (PA) as a skeleton material in a controlled manner without surface modification. Fluorescein isothiocyanate-labeled epidermal growth factor receptor (EGFR) peptide nanoparticles (NPs) could specifically bind to EGFR-positive liver tumor cells. EGFR peptide magnetic vesicles (EPMVs) could efficiently recognize and separate hepatoma carcinoma cells from cell solutions and treated blood samples (ratio of magnetic EPMVs versus anti-EpCAM NPs: 3.5 ± 0.29). Analysis of the circulating tumor cell (CTC) count in blood samples from 32 patients with liver cancer showed that EPMVs could be effectively applied for CTC capture. Thus, this nanoscale, targeted cargo-packaging technology may be useful for designing cancer diagnostic systems.

Reduction-sensitive amphiphilic dextran derivatives as theranostic nanocarriers for chemotherapy and MR imaging

Reduction-sensitive, amphiphilic dextran derivatives were developed from disulfide-linked dextran-g-poly-(N-ε-carbobenzyloxy-l-lysine) graft polymer (Dex-g-SS-PZLL), and used as theranostic nanocarriers for chemotherapy and MR imaging.

In vivo assessment of the vascular disrupting effect of M410 by DCE-MRI biomarker in a rabbit model of liver tumor

The present study aimed to prospectively monitor the vascular disrupting effect of M410 by dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in rabbits with VX2 liver tumors. Twenty-eight rabbits bearing VX2 tumors in the left lobe of the liver were established and randomly divided into treatment and control groups, intravenously injected with 25 mg/kg M410 or sterile saline, respectively. Conventional and DCE-MRI data were acquired on a 3.0-T MR unit at pretreatment, 4 h, 1, 4, 7 and 14 days post-treatment. Histopathological examinations [hematoxylin and eosin (H&E) and CD34 immunohistochemisty staining] were performed at each time point. The dynamic changes in tumor volume, kinetic DCE-MRI parameter [volume transfer constant (Ktrans)] and histological data were evaluated. Tumors grew slower in the M410 group 4-14 days following treatment, compared with rapidly growing tumors in the control group (P<0.05). At 4 h, 1 and 4 days, Ktrans significantly decreased in the M410 group compared with that in the control group (P<0.05). However, Ktrans values were similar in the two groups for the other time points studied. The changes in DCE-MRI parameters were consistent with the results obtained from H&E and CD34 staining of the tumor tissues. DCE-MRI parameter Ktrans may be used as a non-invasive imaging biomarker to monitor the dynamic histological changes in tumors following treatment with the vascular targeting agent M410.

Pineal parenchymal tumours: minimum apparent diffusion coefficient in prediction of tumour grading

Retrospective assessment was performed of the minimum apparent diffusion coefficient (minADC) together with quantitative assessment of the histopathological features of resected tumour tissue and the Ki-67 labelling index (LI) for predicting pineal parenchymal tumour (PPT) grade. Magnetic resonance images of tumours from 26 male and female patients (mean age 27.7 years) with pathologically confirmed PPTs, comprising 10 pineocytomas (PCs), seven pineal parenchymal tumours of intermediate differentiation (PPTIDs) and nine pineoblastomas (PBs), were reviewed retrospectively. Using ADC maps derived from isotropic diffusion-weighted images, the minADC value of each tumour was determined postoperatively from several regions of interest defined in the tumour, excluding cystic, necrotic, haemorrhagic or calcified components. Surgical intervention was undertaken in all cases. The Ki-67 LI was measured in surgical specimens. Mean minADC and Ki-67 LI showed significant differences among PCs, PPTIDs and PBs, and minADC was negatively correlated with Ki-67 LI. It is concluded that the minADC of PPTs provide useful additional information when predicting tumour grading.

[Corpus callosum and middle cerebellar peduncles in schizophrenic patients: a diffusion tensor imaging study upon the initial onset]

OBJECTIVE

To investigate the value of diffusion tenser image (DTI) in identifying subtle abnormalities in the corpus callosum and bilateral middle cerebellar peduncles in patients with the initial onset of schizophrenia.

METHODS

Twenty patients with the first episode of schizophrenia and 18 healthy subjects were examined by DTI. Fractional anisotropy (FA) and averaged diffusion coefficient (ADC) were measured in the bilateral middle cerebellar peduncles, genu and splenium of the corpus callosum. Independent-sample t test was used to compare the value of FA and ADC between the two groups.

RESULT

The FA of the bilateral middle cerebellar peduncles was significantly lower in the schizophrenic patients than in the healthy subjects (P<0.05), but that in the genu and splenium of the corpus callosum were comparable between the two groups (P>0.05). The ADC values showed no significant difference in all the above regions between the two groups (P>0.05).

CONCLUSION

Subtle abnormal changes occur in the cerebrum-cerebellumto circuit in schizophrenic patients, and may trigger the onset of the symptoms in the early stages of schizophrenia.

[Clinical investigation of conservative treatment for volar Barton fracture]

OBJECTIVE

To discuss the indication and outcome of volar Barton fracture treated by nonoperative method.

METHODS

Twenty-three cases of volar Barton fracture treated by closed method included 8 male and 15 female with an average age of 52.2 years,ranging 16 to 84 years. Among them, 16 cases showed subluxation of the carpus (15 cases were Mehara type I ,1 case was Mehara type III) by radiographs except the other 7 cases. By the experimentation in 32 cadavers, the injury of dorsal radiocarpal ligament was supposed to be a very important cause of the subluxation of the radiocarpal joint. The criteria of Pattee and Thompson was used to evaluate the outcome of the treatment.

RESULTS

Twenty-three patients were followed up for 7 to 70 months, 11 cases gained satisfactory outcome (1 case as excellent, 10 cases as good), 12 cases gained unsatisfactory outcome (5 cases as fair, 7 cases as poor). Five of 7 cases without the subluxation of the carpus by the radiographs gained satisfactory outcome. Six of 16 cases with the subluxation of the carpus gained satisfactory outcome.

CONCLUSION

(1) The result of reduction will influence the outcome of the treatment, the step on articular surface shoud be less than 2 mm after reduction. (2) Nonoperative method is recommended if volar Barton fractures are not associated with subluxation of the carpus. (3) Nonoperative method can be tried first if the fractures associated with the subluxation of the carpus, however operation is recommended when the articular step is more than 2 mm.

Fine mapping of a major quantitative trait loci, qSSP7, controlling the number of spikelets per panicle as a single Mendelian factor in rice

In our previous studies, one putative QTL affecting number of spikelets per panicle (SPP) was identified in the pericentromeric region of rice chromosome 7 using a recombinant inbred population. In order to define the QTL (qSPP7), RI50, a recombinant inbred line with 70% of genetic background same as the female parent of Zhenshan 97, was selected to produce near-isogenic lines for the target region in the present study. In a BC(2)F(2) population consisting of 190 plants, the frequency distribution of SPP was shown to be discontinuous and followed the expected Mendelian ratios (1:2:1 by progeny test) for single locus segregation. qSPP7 was mapped to a 0.4 cM region between SSR marker RM3859 and RFLP marker C39 based on tests of the BC(2)F(2) population and its progeny. Its additive and dominant effects on SPP were 51.1 and 24.9 spikelets, respectively. Of great interest, the QTL region also had effects on grain yield per plant (YD), 1,000 grain weight (GW), tillers per plant (TPP) and seed setting ratio (SR). Significant correlations were observed between SPP and YD (r = 0.66) and between SPP and SR (r = -0.29) in the progeny test. 1082 extremely small panicle plants of a BC(3)F(2) population containing 8,400 individuals were further used to fine map the QTL. It turns out that qSPP7 co-segregated with two markers, RM5436 and RM5499 spanning a physical distance of 912.4 kb. Overall results suggested that recombination suppression occurred in the region and positional cloning strategy is infeasible for qSPP7 isolation. The higher grain yield of Minghui 63 homozygote as compared to the heterozygote suggested that Minghui 63 homozygote at qSPP7 in hybrid rice could further improve its yield.

Cytotoxic diterpenoids and sesquiterpenoids from Pteris multifida

Three new ent-kaurane diterpenoids, named pterokaurane M 1-M 3 ( 1- 3) and three new C 14 pterosin-sesquiterpenoids, named multifidoside A-C ( 4- 6), along with 18 known compounds, were isolated from the whole plants of Pteris multifida . The structures of 1- 6 were established using spectroscopic methods, including extensive 2D NMR and CD analyses. Compounds 4 and 5 showed cytotoxicity against the HepG2 tumor cell line with IC 50 values of less than 10 microM.

Role of TFF in healing of stress-induced gastric lesions

AIM: To determine the changes of pS2 and ITF of TFF expression in gastric mucosa and the effect on ulcer healing of pS2, ITF to Water-immersion and restraint stress (WRS) in rats.

METHODS: Wistar rats were exposed to single or repeated WRS for 4 h every other day for up to 6 days.Gastric mucosal blood flow (GMBF) was measured by LDF-3 flowmeter and the extent of gastric mucosal lesions were evaluated grossly and histologically. Expression of pS2 and ITF mRNA was determined by RT-PCR. Immunohistochemistry was used to further detect the expression of pS2 and ITF.

RESULTS: WRS applied once produced numerous gastric mucosal erosions, but the number of these lesions gradually declined and GMBF restored at 2, 4, 8 h after stress. The area of gastric mucosal lesion was reduced by 64.9% and GMBF was increased by 89.8% at 8 h. The healing of stress-induced ulcerations was accompanied by increased expression of pS2 (0.51 ± 0.14 vs 0.77 ± 0.11, P < 0.01) and ITF (0.022 ± 0.001vs 0.177 ± 0.010, P < 0.01). The results were demonstrated further by immunohistochemistry of pS2 (0.95 ± 0.11 vs 1.41 ± 0.04, P < 0.01) and ITF (0.134 ± 0.001 vs 0.253 ± 0.01,P < 0.01). With repeated WRS, adaptation to this WRS developed, the area of gastric mucosal lesions was reduced by 22.0% after four consecutive WRS. This adaptation to WRS was accompanied by increased GMBF (being increased by 94.2%), active cell proliferation in the neck region of gastric glands, and increased expression of pS2 (0.37 ± 0.02 vs 0.77 ± 0.01, P < 0.01) and ITF (0.040 ± 0.001vs 0.372 ± 0.010, P < 0.01). The result was demonstrated further by immunohistochemistry of pS2 (0.55 ± 0.04 vs 2.46 ± 0.08, P < 0.01) and ITF (0.134 ± 0.001vs 0.354 ± 0.070, P < 0.01).

CONCLUSION: TFF may not only participate in the early phase of epithelial repair known as restitution(maked by increased cell migration),but also play an important role in the subsequent,protracted phase of glandular renewal(made by cell proliferation).

Crystallization and preliminary X-ray study of the edema factor exotoxin adenylyl cyclase domain from Bacillus anthracis in the presence of its activator, calmodulin

Edema factor from Bacillus anthracis is a 92 kDa secreted adenylyl cyclase exotoxin and is activated by the host-resident protein calmodulin. Calmodulin is a ubiquitous intracellular calcium sensor in eukaryotes and activates edema factor nearly 1000-fold upon binding. While calmodulin has many known effectors, including kinases, phosphodiesterases, motor proteins, channels and type 1 adenylyl cyclases, no structures of calmodulin in complex with a functional enzyme have been solved. The crystallization and initial experimental phasing of crystals containing a complex of edema factor adenylyl cyclase domain and calmodulin are reported here. The edema factor-calmodulin complex crystallizes in three different space groups. A native data set in the I222 space group has been collected to 2.7 A and the self-rotation function solution suggests three edema factor-calmodulin complexes in each asymmetric unit. Initial 4 A phases were obtained by selenomethionyl MAD in combination with two heavy-atom derivatives. These phases were successfully extended to 2.7 A using NCS averaging.

The regulation of type 7 adenylyl cyclase by its C1b region and Escherichia coli peptidylprolyl isomerase, SlyD

Mammalian membrane-bound adenylyl cyclase consists of two highly conserved cytoplasmic domains (C1a and C2a) separated by a less conserved connecting region, C1b, and one of two transmembrane domains, M2. The C1a and C2a domains form a catalytic core that can be stimulated by forskolin and the stimulatory G protein subunit alpha (Galpha(s)). In this study, we analyzed the regulation of type 7 adenylyl cyclase (AC7) by C1b. The C1a, C1b, and C2a domains of AC7 were purified separately. Escherichia coli SlyD protein, a cis-trans peptidylprolyl isomerase (PPIase), copurifies with AC7 C1b (7C1b). SlyD protein can inhibit the Galpha(s)- and/or forskolin-activated activity of both soluble and membrane-bound AC7. Mutant forms of SlyD with reduced PPIase activity are less potent in the inhibition of AC7 activity. Interestingly, different isoforms of mammalian membrane-bound adenylyl cyclase can be either inhibited or stimulated by SlyD protein, raising the possibility that mammalian PPIase may regulate enzymatic activity of mammalian adenylyl cyclase. Purified 7C1b-SlyD complex has a greater inhibitory effect on AC7 activity than SlyD alone. This inhibition by 7C1b is abolished in a 7C1b mutant in which a conserved glutamic acid (amino acid residue 582) is changed to alanine. Inhibition of adenylyl cyclase activity by 7C1b is further confirmed by using 7C1b purified from an E. coli slyD-deficient strain. This inhibitory activity of AC7 is also observed with the 28-mer peptides derived from a region of C1b conserved in AC7 and AC2 but is not observed with a peptide derived from the corresponding region of AC6. This inhibitory activity exhibited by the C1b domain may result from the interaction of 7C1b with 7C1a and 7C2a and may serve to hold AC7 in the basal nonstimulated state.

Inhibition of adenylyl and guanylyl cyclase isoforms by the antiviral drug foscarnet

The pyrophosphate (PP(i)) analog foscarnet inhibits viral DNA-polymerases and is used to treat cytomegalovirus and human immunodeficiency vius infections. Nucleotide cyclases and DNA-polymerases catalyze analogous reactions, i.e. a phosphodiester bond formation, and have similar topologies in their active sites. Inhibition by foscarnet of adenylyl cyclase isoforms was therefore tested with (i) purified catalytic domains C1 and C2 of types I and VII (IC1 and VIIC1) and of type II (IIC2) and (ii) membrane-bound holoenzymes (from mammalian tissues and types I, II, and V heterologously expressed in Sf9 cell membranes). Foscarnet was more potent than PP(i) in suppressing forskolin-stimulated catalysis by both, IC1/IIC2 and VIIC1/IIC2. Stimulation of VIIC1/IIC2 by Galpha(s) relieved the inhibition by foscarnet but not that by PP(i). The IC(50) of foscarnet on membrane-bound adenylyl cyclases also depended on their mode of regulation. These findings predict that receptor-dependent cAMP formation is sensitive to inhibition by foscarnet in some, but not all, cells. This was verified with two cell lines; foscarnet blocked cAMP accumulation after A(2A)-adenosine receptor stimulation in PC12 but not in HEK-A(2A) cells. Foscarnet also inhibited soluble and, to a lesser extent, particulate guanylyl cylase. Thus, foscarnet interferes with the generation of cyclic nucleotides, an effect which may give rise to clinical side effects. The extent of inhibition varies with the enzyme isoform and with the regulatory input.

An extended conformation of calmodulin induces interactions between the structural domains of adenylyl cyclase from Bacillus anthracis to promote catalysis

The edema factor exotoxin produced by Bacillus anthracis is an adenylyl cyclase that is activated by calmodulin (CaM) at resting state calcium concentrations in infected cells. A C-terminal 60-kDa fragment corresponding to the catalytic domain of edema factor (EF3) was cloned, overexpressed in Escherichia coli, and purified. The N-terminal 43-kDa domain (EF3-N) of EF3, the sole domain of edema factor homologous to adenylyl cyclases from Bordetella pertussis and Pseudomonas aeruginosa, is highly resistant to protease digestion. The C-terminal 160-amino acid domain (EF3-C) of EF3 is sensitive to proteolysis in the absence of CaM. The addition of CaM protects EF3-C from being digested by proteases. EF3-N and EF3-C were expressed separately, and both fragments were required to reconstitute full CaM-sensitive enzyme activity. Fluorescence resonance energy transfer experiments using a double-labeled CaM molecule were performed and indicated that CaM adopts an extended conformation upon binding to EF3. This contrasts sharply with the compact conformation adopted by CaM upon binding myosin light chain kinase and CaM-dependent protein kinase type II. Mutations in each of the four calcium binding sites of CaM were examined for their effect on EF3 activation. Sites 3 and 4 were found critical for the activation, and neither the N- nor the C-terminal domain of CaM alone was capable of activating EF3. A genetic screen probing loss-of-function mutations of EF3 and site-directed mutations based on the homology of the edema factor family revealed a conserved pair of aspartate residues and an arginine that are important for catalysis. Similar residues are essential for di-metal-mediated catalysis in mammalian adenylyl cyclases and a family of DNA polymerases and nucleotidyltransferases. This suggests that edema factor may utilize a similar catalytic mechanism.

[A hanger-needless infusion set and it's unique infusion tube]

The design of an enclosed barrel with an interiorly compresed plunges is introduced in the paper. With a unique floating-bulb-design tube, the new infusion set makes liquid infusion easy at any height, in any direction, with no need of hanger and without any risk of theleast possibility of any air into blood vessels. It is suitable for prehospital rescue, battle field treatment and wounded Rersonnels' transpostation etc. The new infusion set can also be tailored or improved according to the different requirements of usess and clinical applications.

Chronic morphine augments adenylyl cyclase phosphorylation: relevance to altered signaling during tolerance/dependence

Despite the demonstration that chronic morphine increases phosphorylation of multiple substrate proteins, their identity has, for the most part, remained elusive. Thus far, chronic morphine has not been shown to increase the phosphorylation of any identified effector protein. This is the first demonstration that persistent activation of opioid receptors has profound effects on phosphorylation of adenylyl cyclase (AC). A dramatic increase in phosphorylation of AC (type II family) was observed in ileum longitudinal muscle myenteric plexus preparations obtained from chronic morphine-treated guinea pigs. Analogous results were obtained when AC was immunoprecipitated using two differentially directed AC antibodies. The magnitude of the augmented AC phosphorylation was substantially attenuated by chelerythrine, a protein kinase C-selective inhibitor. These results suggest the potential relevance of increased phosphorylation (protein kinase C-mediated) of AC to opioid tolerant/dependent mechanisms. Because phosphorylation of AC isoforms (type II family) can significantly increase their stimulatory responsiveness to Gsalpha and Gbetagamma, this mechanism could underlie, in part, the predominance of opioid AC stimulatory signaling observed in opioid tolerant/dependent tissue. Moreover, in light of the fact that many G protein-coupled receptors signal through common effector proteins, this effect provides a mechanism for divergent consequences of chronic morphine treatment and could explain the well documented complexity of changes that accompany the opioid tolerant/dependent state.

The C2 catalytic domain of adenylyl cyclase contains the second metal ion (Mn2+) binding site

Membrane-bound mammalian adenylyl cyclase isoforms contain two internally homologous cytoplasmic domains (C1 and C2). When expressed separately, C1 and C2 are catalytically inactive, but conversion of ATP to cAMP is observed if C1 and C2 are combined. By analogy with DNA polymerases, adenylyl cyclases are thought to require two divalent metal ions for nucleotide binding and phosphodiester formation; however, only one Mg2+ ion (liganded to C1) has been visualized in the recently solved crystal structure of a C1-C2 complex [Tesmer, J. J. G., Sunahara, R. K., Gilman, A. G., and Sprang, S. R. (1997) Science 278, 1907-1916]. Here, we have studied the binding of ATP to IIC2 (from type II adenylyl cyclase) using ATP analogues [2',3'-dialdehyde ATP (oATP), a quasi-irreversible inhibitor that is covalently incorporated via reduction of a Schiff base, the photoaffinity ligand 8-azido-ATP (8N3-ATP), and trinitrophenyl-ATP (TNP-ATP), a fluorescent analogue] and fluorescein isothiocyanate (FITC). [alpha-32P]oATP and 8N-[alpha-32P]ATP are specifically incorporated into IIC2. Labeling of IIC2 by [alpha-32P]oATP and by FITC is greatly enhanced by Mn2+ and to a much lesser extent by Mg2+. Similarly, TNP-ATP binds to IIC2 as determined by fluorescence enhancement, and this binding is promoted by Mn2+. Thus, a second metal ion binding site (preferring Mn2+) is contained within the C2 domain, and this finding highlights the analogy in the reaction catalyzed by DNA polymerases and adenylyl cyclases.

Chronic morphine augments G(beta)(gamma)/Gs(alpha) stimulation of adenylyl cyclase: relevance to opioid tolerance

In the current study, we investigated the neurochemical basis for the previously reported predominance of stimulatory mu-opioid signaling in guinea pig longitudinal muscle/myenteric plexus (LMMP) preparations after chronic in vivo morphine exposure. As expected, recombinant Gsalpha (rGsalpha) dose-dependently stimulated adenylyl cyclase (AC) activity in LMMP membranes obtained from opioid naive as well as tolerant LMMP tissue. However, the magnitude of the increase was significantly greater in the latter than in the former. The Gbetagamma blocking peptide QEHA (50 microM) essentially abolished stimulation by rGsalpha in LMMP membranes obtained from both opioid naive and tolerant animals. Interestingly, after partial blockade by lower QEHA concentrations, the incremental AC stimulation by rGsalpha in tolerant LMMP membranes was no longer observed, indicating augmented Gbetagamma stimulatory responsiveness. Concomitant changes in the content of AC isoform protein are consistent with these biochemical observations. After chronic systemic morphine, AC protein is augmented significantly (56%). This increment is most likely to be composed of AC isoforms that are stimulated by Gbetagamma. This is the first demonstration in a complex mammalian tissue that persistent activation of opioid receptors results in augmented Gbetagamma/Gsalpha AC stimulatory interactiveness. The relevance of such changes to the manifestation of opioid tolerance is discussed.

Conversion of forskolin-insensitive to forskolin-sensitive (mouse-type IX) adenylyl cyclase

Forskolin potently activates all cloned mammalian adenylyl cyclases except type IX by interacting with two homologous cytoplasmic domains (C1 and C2) that form the catalytic core. A mutational analysis of the IIC2 protein (C2 domain from type II adenylyl cyclase) and forskolin analogs suggests that Ser942 interacts with the 7-acetyl group of forskolin. The C1/C2 complex has only one forskolin, one ATP, and one binding site for the alpha subunit of the G protein that stimulates adenylyl cyclase (Gsalpha) and its structure may be modeled using the three-dimensional structure of (IIC2/forskolin)2. The Ser942 mutation defines which forskolin in the (IIC2/forskolin)2 structure exists in C1/C2 complex. Thus, the forskolin-binding site is close to the Gsalpha-binding site but distal (15-20A) from the catalytic site. Mutation from Leu912 of IIC2 protein to tyrosine or alanine severely reduces Gsalpha activation and completely prevents forskolin activation. The corresponding residue of Leu912 is Tyr1082 at type IX isoform of adenylyl cyclase. Similar to recombinant type IX enzyme, soluble adenylyl cyclase derived from mouse-type IX adenylyl cyclase is sensitive to Gsalpha activation but not to forskolin. Changing Tyr1082 to leucine makes soluble type IX adenylyl cyclase forskolin-responsive.

Three discrete regions of mammalian adenylyl cyclase form a site for Gsalpha activation

The interaction between the alpha subunit of G protein Gs (Gsalpha) and the two cytoplasmic domains of adenylyl cyclase (C1 and C2) is a key step in the stimulation of cAMP synthesis by hormones. Mutational analysis reveals that three discrete regions in the primary sequence of adenylyl cyclase affect the EC50 values for Gsalpha activation and thus are the affinity determinants of Gsalpha. Based on the three-dimensional structure of C2.forskolin dimer, these three regions (C2 alpha2, C2 alpha3/beta4, and C1 beta1) are close together and form a negatively charged and hydrophobic groove the width of an alpha helix that can accommodate the positively charged adenylyl cyclase binding region of Gsalpha. Two mutations in the C2 alpha3/beta4 region decrease the Vmax values of Gsalpha activation without an increase in the EC50 values. Since these three regions are distal to the catalytic site, the likely mechanism for Gsalpha activation is to modulate the structure of the active site by controlling the orientation of the C2 alpha2 and alpha3/beta4 structures.

The conserved asparagine and arginine are essential for catalysis of mammalian adenylyl cyclase

Mammalian adenylyl cyclases have two homologous cytoplasmic domains (C1 and C2), and both domains are required for the high enzymatic activity. Mutational and genetic analyses of type I and soluble adenylyl cyclases suggest that the C2 domain is catalytically active and the C1 domain is not; the role of the C1 domain is to promote the catalytic activity of the C2 domain. Two amino acid residues, Asn-1025 and Arg-1029 of type II adenylyl cyclase, are conserved among the C2 domains, but not among the C1 domains, of adenylyl cyclases with 12 putative transmembrane helices. Mutations at each amino acid residue alone result in a 30-100-fold reduction in Kcat of adenylyl cyclase. However, the same mutations do not affect the Km for ATP, the half-maximal concentration (EC50) for the C2 domain of type II adenylyl cyclase to associate with the C1 domain of type I adenylyl cyclase and achieve maximal enzyme activity, or the EC50 for forskolin to maximally activate enzyme activity with or without Gsalpha. This indicates that the mutations at these two residues do not cause gross structural alteration. Thus, these two conserved amino acid residues appear to be crucial for catalysis, and their absence from the C1 domains may account for its lack of catalytic activity. Mutations at both amino acid residues together result in a 3,000-fold reduction in Kcat of adenylyl cyclase, suggesting that these two residues have additive effects in catalysis. A second site suppressor of the Asn-1025 to Ser mutant protein has been isolated. This suppressor has 17-fold higher activity than the mutant and has a Pro-1015 to Ser mutation.

Characterization and crystallization of a minimal catalytic core domain from mammalian type II adenylyl cyclase

Adenylyl cyclases play a pivotal role in signal transduction by carrying out the regulated synthesis of cyclic AMP. The nine cloned mammalian adenylyl cyclases all share two conserved regions of sequence, C1 and C2, which are homologous to each other and are together responsible for catalytic activity. Recombinant C1 and C2 domains catalyze the synthesis of cyclic AMP when they are mixed and activated by forskolin, and C2 domains alone also manifest reduced levels of forskolin-stimulated enzyme activity. Using limited proteolysis and mass spectrometry, we have mapped the boundaries of a minimal stable and active C2 catalytic domain to residues 871-1090 of type II adenylyl cyclase. We report the properties and crystallization of this trimmed domain, termed IIC2-delta 4. Crystals belong to space group P4n2(1)2, where n = 1 or 3; a = b = 81.3, and c = 180.5 A; and there are two molecules per asymmetric unit related by an approximate body centering operation. Flash-frozen crystals diffract anisotropically to 2.2 A along the c* direction and to 2.8 A along the a* and b* directions using synchrotron radiation.

AP1 enhances polyomavirus DNA replication by promoting T-antigen-mediated unwinding of DNA

An early step in the initiation of polyomavirus DNA replication is viral large-T-antigen-mediated unwinding of the origin. We report that components of the AP1 transcription factor, Fos and Jun, interact with T antigen in vitro to enhance unwinding of the viral origin. This provides a biochemical basis for the capacity of AP1 to activate viral DNA replication in vivo.

Irreversible inhibition of forskolin interactions with type I adenylyl cyclase by a 6-isothiocyanate derivative of forskolin

Forskolin (Fsk) has been demonstrated to interact directly with the enzyme adenylyl cyclase (EC 4.6.1.1) in diverse tissues. However, the ability of Fsk to bind to and activate adenylyl cyclase varies depending on the tissue being studied. Different adenylyl cyclase subtypes have been cloned and expressed in a recombinant Sf9 expression system. This provides an opportunity to study the effects of chemically reactive derivatives of Fsk on individual adenylyl cyclase subtypes in the absence of Gs alpha. Reaction of type I adenylyl cyclase with an isothiocyanate derivative of Fsk (6-[[N-(2-isothiocyanatoethyl)amino]carbonyl]forskolin) causes irreversible inhibition of Fsk binding with an IC50 of 300 nM and irreversible inhibition of Fsk activation with an IC50 of 10 microM, suggesting that there are two sites of 6-[[N-(2-isothiocyanatoethyl)amino]carbonyl]forskolin interaction. These studies establish the usefulness of the isothiocyanate derivative of Fsk in localizing the site(s) of Fsk interaction with type I adenylyl cyclase.

Forskolin carbamates: binding and activation studies with type I adenylyl cyclase

Three series of analogs were regioselectively prepared from a protected forskolin precursor to afford 7-carbamoyl-7-desacetylforskolins (series 1), 6-carbamoyl-7-desacetylforskolins (series 2), and 6-carbamoylforskolins (series 3). The analogs were pharmacologically evaluated for binding (IC50) to and activation (EC50) of type I adenylyl cyclase in membranes from stably transfected Sf9 cell lines expressing a single adenylate cyclase subtype. The following ranges were determined for the IC50's and EC50's of each individual series: series 1, IC50 = 43-1600 nM, EC50 = 0.5-9.6 microM; series 2, IC50 = 65-680 nM, EC50 = 0.63-6.5 microM; series 3, IC50 = 21-271 nM, EC50 = 0.5-8.1 microM (forskolin IC50 = 41 nM and EC50 = 0.5 microM). Activation paralleled binding; however, some analogs exhibited poor binding and good activation whereas others demonstrated good binding but poor activation. Steric bulk tended to diminish binding and activation when at the 6- or 7-position, although bulk was accommodated at the 6-position if the 7-site was reacetylated. Acylation of the 7-position by the carbamoyl linker or acetyl was important for obtaining good binding and activation; however, the effect was more pronounced with binding. For both binding and activation, small, linear, lipophilic substituents (propyl, allyl, isopropyl) are well tolerated at the 7-position but less so in the 6-position, even when the 7-site is reacetylated. Planar aromatic moieties (phenyl and 2-pyridinyl) demonstrated moderate to good potency for binding and activation when located at either the 6- or 7-positions. There is an overall trend toward increasing potency for both binding and activation with polar substituents.