Prevalence and risk factors for subjective cognitive decline and the correlation with objective cognition among community-dwelling older adults in China: Results from the Hubei memory and aging cohort study

INTRODUCTION

The prevalence and risk factors for subjective cognitive decline (SCD) and its correlation with objective cognition decline (OCD) among community-dwelling older adults is inconsistent.

METHODS

Older adults underwent neuropsychological and clinical evaluations to reach a consensus on diagnoses.

RESULTS

This study included 7486 adults without mild cognitive impairment and dementia (mean age: 71.35 years [standard deviation = 5.40]). The sex-, age-, and residence-adjusted SCD prevalence was 58.33% overall (95% confidence interval: 58.29% to 58.37%), with higher rates of 61.25% and 59.87% in rural and female subgroups, respectively. SCD global and OCD language, SCD memory and OCD global, SCD and OCD memory, and SCD and OCD language were negatively correlated in fully adjusted models. Seven health and lifestyle factors were associated with an increased risk for SCD.

DISCUSSION

SCD affected 58.33% of older adults and may indicate concurrent OCD, which should prompt the initiation of preventative intervention for dementia.

HIGHLIGHTS

SCD affects 58.33% of older adults in China. SCD may indicate concurrent objective cognitive decline. Difficulty finding words and memory impairments may indicate a risk for AD. The presence of SCD may prompt preventative treatment initiation of MCI or dementia. Social network factors may be initial targets for the early prevention of SCD.

Effect of whole body vibration therapy in the rat model of steroid-induced osteonecrosis of the femoral head

Background: Steroid-induced Osteonecrosis of the Femoral Head (SIONFH) is a skeletal disease with a high incidence and a poor prognosis. Whole body vibration therapy (WBVT), a new type of physical training, is known to promote bone formation. However, it remains unclear whether WBVT has a therapeutic effect on SIONFH. Materials and methods: Thirty adult male and female Sprague-Dawley (SD) rats were selected and randomly assigned to three experimental groups: the control group, the model group, and the mechanical vibration group, respectively. SIONFH induction was achieved through the combined administration of lipopolysaccharides (LPS) and methylprednisolone sodium succinate for injection (MPS). The femoral head samples underwent hematoxylin and eosin (H&E) staining to visualize tissue structures. Structural parameters of the region of interest (ROI) were compared using Micro-CT analysis. Immunohistochemistry was employed to assess the expression levels of Piezo1, BMP2, RUNX2, HIF-1, VEGF, CD31, while immunofluorescence was used to examine CD31 and Emcn expression levels. Results: The H&E staining results revealed a notable improvement in the ratio of empty lacuna in various groups following WBVT intervention. Immunohistochemical analysis showed that the expression levels of Piezo1, BMP2, RUNX2, HIF-1, VEGF, and CD31 in the WBVT group exhibited significant differences when compared to the Model group (p < 0.05). Additionally, immunofluorescence analysis demonstrated statistically significant differences in CD31 and Emcn expression levels between the WBVT group and the Model group (p < 0.05). Conclusion: WBVT upregulates Piezo1 to promote osteogenic differentiation, potentially by enhancing the HIF-1α/VEGF axis and regulating H-vessel angiogenesis through the activation of the Piezo1 ion channel. This mechanism may lead to improved blood flow supply and enhanced osteogenic differentiation within the femoral head.

Mechanical properties of trabeculae and osteocyte morphology change significantly in different areas of the necrotic femoral head

Background: Osteonecrosis of the femoral head is a complex hip ailment. The precise changes in bone tissue during the disease's onset remain unclear. It is vital to assess both the quantity and quality of the trabecular state in a necrotic femoral head. Aim: This study aims to identify and compare the ultrastructural changes in osteocyte morphology and nanomechanical characteristics within various regions of necrotic femoral heads. Methods: Between December 2016 and May 2023, we gathered ten necrotic femoral heads from patients and five femoral heads from cadavers. The samples from the necrotic femoral heads were categorized into three areas: necrotic, sclerotic, and normal. Our assessment methods encompassed hematoxylin and eosin staining, sclerostin (SOST) immunohistochemistry, micro-computed tomography, nanoindentation, and acid-etched scanning electron microscopy. These techniques enabled us to examine the SOST expression, trabecular microstructure, micromechanical properties of trabeculae, and modifications in osteocyte morphology at the ultrastructural level. Results: The protein level of SOST was found to be lower in the sclerotic area. In the necrotic area, decreased values of bone volume fraction, trabecular thickness, and trabecular number and an increased value of trabecular separation were found. Conversely, in the sclerotic area, higher mean values of bone volume fraction, trabecular number, and trabecular thickness and lower trabecular separation indicated significant changes in the structural characteristics of trabeculae. Compared with the healthy area, the elastic modulus and hardness in the sclerotic area were significantly higher than those in the necrotic, normal, and control areas, while those in necrotic areas were significantly lower than those in the healthy area. The number of osteocytes tended to increase in the sclerotic area with more canalicular cells compared to the healthy area and control group. Conclusion: These results imply that the stress distribution within the sclerotic area could potentially lead to enhanced trabecular quality and quantity. This effect is also reflected in the increased count of osteocytes and their canaliculars. It is plausible that the sclerotic trabecular bone plays a pivotal role in the repair of necrotic femoral heads.

[Analysis of natural regression and influencing factors of HSIL in the cervix of childbearing age patients]

Objective: To investigate the natural regression and related factors of high-grade squamous intraepithelial lesion (HSIL) in the cervix of childbearing age women, and to evaluate the applicability of conservative management for future fertility needs. Methods: This study included 275 patients of reproductive age with fertility needs, who were diagnosed as HSIL by biopsy from April 30, 2015 to April 30, 2022, including 229 cases (83.3%) cervical intraepithelial neoplasia (CIN) Ⅱ and 46 cases (16.7%) CIN Ⅱ-Ⅲ. They were followed-up without immediate surgery in the First Affiliated Hospital of Nanjing Medical University. The median follow-up time was 12 months (range: 3-66 months). The regression, persistence and progression of lesions in patients with HSIL were analyzed during the follow-up period, the influencing factors related to regression and the time of regression were analyzed. Results: (1) Of the 275 HSIL patients, 213 cases (77.5%, 213/275) experienced regression of the lesion during the follow-up period. In 229 CIN Ⅱ patients, 180 cases (78.6%) regressed, 21 cases (9.2%) persisted, and 28 cases (12.2%) progressed. In 46 CIN Ⅱ-Ⅲ patients, 33 cases (71.7%) regressed, 12 cases (26.1%) persisted, and 1 case (2.2%) progressed to invasive squamous cell carcinoma stage Ⅰ a1. There was no significant difference in the regression rate between the two groups (χ²=1.03, P=0.309). (2) The average age at diagnosis, age <25 years old at diagnosis were independent influencing factor of HSIL regression in univariate analysis (all P<0.05). There was no significant difference between HSIL regression and pathological grading, the severity of screening results, human papillomavirus (HPV) genotype, colposcopy image characteristics, number of biopsies during follow-up and pregnancy experience (all P>0.05). (3) The median regression times for patients aged ≥25 years and <25 years at diagnosis were 15 and 12 months, respectively. Kaplan-Meier analysis showed that age ≥25 years at diagnosis significantly increased the median regression time compared to <25 years (χ²=6.02, P=0.014). Conclusions: For HSIL patients of childbearing age, conservative management without immediate surgical intervention is preferred if CINⅡ is fully evaluated through colposcopy examination. Age ≥25 years at diagnosis is a risk factor affecting the prognosis of HSIL patients.

Global research trends and hotspots in calcaneal fracture: A bibliometric analysis (2000-2021)

Background

Calcaneal fracture is common and carries high morbidity and disability. Its treatment is therefore of vital concern. Many topics concerning calcaneal fracture remain controversial, and the subject has not yet been well-researched. We aim to analyze and illustrate the trends in development, overall knowledge structure, "hotspots," and research frontiers on the topic of calcaneal fracture.

Methods

Literature relating to calcaneal fracture published between 2000 and 2021 was retrieved from Science Citation Index Expanded (SCIE) database of the Web of Science. Three bibliometric tools (Bibliometrix, CiteSpace, and VOSviewer software) were used for analysis and the generation of knowledge maps. Annual trends in publication counts and the relative contributions of different countries, regions, institutions, authors, and journals, as well as keyword clusters, "hot topics," and research frontiers, were analyzed.

Results

A total of 1,687 publications were included in the analysis. The number of calcaneal fracture articles published worldwide each year was highest in 2019, with a total of 128 articles. The United States has made the greatest contribution to the field, with the largest number of publications and the highest H-index. Foot & Ankle International was the most productive journal, publishing a total of 167 articles on calcaneal fracture during the study period. Hebei Medical University of China and the University of California, San Francisco were the most prolific institutions. Professors T. Schepers, S. Rammelt, H. Zwipp, and Y. Z. Zhang have made remarkable contributions to the field. However, the degree of collaboration between researchers and among institutions was relatively low, and took place mainly in Europe and the Americas. All relevant keywords could be categorized into three clusters: studies of internal fixation, studies of fractures, and studies of osteoporosis. A trend of balanced and diversified development could be seen within these clusters. Keywords with ongoing "citation bursts," such as sinus tarsi approach, wound complications, minimally invasive technique, extensile lateral approach, surgical treatment, and plate, may continue to be research "hotspots" in the near future.

Conclusion

Based on current global trends, the number of publications on calcaneal fracture will continue to increase. Topics such as minimally invasive techniques and complications have become important hotspots of research. We recommend enhancing international communication and collaboration for future research in this field.

Bibliometric and visualized analysis of research relating to minimally invasive spine surgery reported over the period 2000-2022

Background

Since entering the 21st century, there has been an increasing interest in minimally invasive surgery for spinal diseases, which has led to the continued development of minimally invasive spine surgery (MISS), with major breakthroughs in technology and technical skills. However, in recent years, there is little relevant research using bibliometrics to analyze the field of MISS research. The purpose of this study is to sort out the publication situation and topic trends of articles in the field of MISS research from the perspective of bibliometrics.

Methods

The articles and reviews related to MISS from 2000 to 2022 were retrieved and downloaded from the Web of Science Core Collection (WOSCC). Visualization and knowledge mapping were performed using three bibliometric tools, including online bibliometric platform, CiteSpace and VOSviewer software. Curve fitting and correlation analysis were performed using Microsoft Excel software. The global research publication output, contributions of countries, institutions, authors, and journals, average citations per item (ACI), Hirsch index (H-index), research hot keywords, etc., in this field were analyzed.

Results

A total of 2384 papers were retrieved, including 2135 original papers and 249 review papers. In the past 22 years, the number of annual publications of MISS research has shown a steady growth trend. China contributed the most papers, and the United States ranked second, but the United States had the highest total citations, and H-index value. The most prolific institutions were Soochow University, Capital Medical University and Wooridul Spine Hospital. In this field, Professors Lee SH, Ahn Y and Yang HL have made significant achievements. However, there is relatively little international collaboration between institutions or researchers. World Neurosurgery is the most published journal on MISS research. According to the keyword co-occurrence analysis, recent keywords mainly focus on researches on minimally invasive modalities, techniques and prognosis, while on the keyword analysis of the ongoing bursts, percutaneous transforaminal endoscopic discectomy, lumbar diskectomy, spinal stenosis, recompression, diskectomy, endoscopic spine surgery, laminectomy, transforaminal lumbar interbody fusion, etc., will likely continue to be a research hotspot in the near future.

Conclusion

Looking at the temporal trend in the number of publications per year, the number of publications for the MISS study will increase in the near future. China has the highest number of publications, but the US has the highest quality publications. International cooperation needs to be further strengthened. Our findings can provide useful information for the academic community and identify possible research fronts and hotspots in the coming years.

Combining frog-leg lateral view may serve as a more sensitive X-ray position in monitoring collapse in osteonecrosis of the femoral head

Load-bearing capacity of the bone structures of anterolateral weight-bearing area plays an important role in the progressive collapse in osteonecrosis of the femoral head (ONFH). The purpose of this study is to assess the efficacy of combined evaluation of anteroposterior (AP) and frog-leg lateral (FLL) view in diagnosing collapse. Between December 2016 and August 2018, a total of 478 hips from 372 patients with ONFH (268 male, 104 female; mean age 37.9 ± 11.4 years) were retrospectively evaluated. All patients received standard AP and FLL views of hip joints. Japanese Investigation Committee (JIC) classification system was used to classify necrotic lesion in AP view. Anterior necrotic lesion was evaluated by FLL view. All patients with pre-collapse ONFH underwent non-operative hip-preserving therapy. The collapse rates were calculated and compared with Kaplan–Meier survival analysis with radiological collapse as endpoints. Forty-four (44/478, 9.2%) hips were classified as type A, 65 (65/478, 13.6%) as type B, 232 (232/478, 48.5%) as type C1 and 137 (137/478, 28.7%) as type C2. Three hundred cases (300/478, 62.5%) were collapsed at the initial time point. Two hundred and twenty six (226/300, 75.3%) hips and 298 (298/300, 99.3%) hips collapse were identified with AP view and FLL view, respectively. An average follow-up of 37.0 ± 32.0 months was conducted to evaluate the occurrence of collapse in 178 pre-collapse hips. Collapses occurred in 89 hips (50.0%). Seventy-seven (77/89, 86.5%) hips were determined with AP view alone and 85 (85/89, 95.5%) hips were determined with the combination of AP and FLL views. The collapse rates at five years were reported as 0% and 0%, 16.2% and 24.3%, 58.3% and 68.1% and 100% and 100% according to AP view alone or combination of AP and FLL views for types A, B, C1 and C2, respectively. The collapse can be diagnosed more accurately by combination of AP and FLL views. Besides, JIC type A and type B ONFH can be treated with conservative hip preservation, but pre-collapse type C2 ONFH should be treated with joint-preserving surgery. Type C1 needs further study to determine which subtype has potential risk of collapse.

The Therapeutic Effect of Huo Xue Tong Luo Capsules in Association Research Circulation Osseous (ARCO) Stage II Osteonecrosis of the Femoral Head: A Clinical Study With an Average Follow-up Period of 7.95 Years

Background: Huo Xue Tong Luo (HXTL) capsules are an oral preparation that could relieve pain and ameliorate osteonecrosis in patients with asymptomatic osteonecrosis of femoral head (ONFH). We wanted to verify whether it could be a treatment option for ARCO stage II ONFH.

Methods: A total of 44 patients (66 hips) with ARCO stage II ONFH were recruited from June 1996 to October 2013 (clinical trial registry number: ChiCTR-RPC-15006,290). HXTL capsules were given under a specific protocol, and the endpoint was set as femoral head collapse. The clinical indicators [including visual analog scale (VAS) and Harris Hip Score (HHS)] and radiological indicators [including Tonnis classification, ARCO stage, Japanese Investigation Committee (JIC) classification, lateral preserved angle (LPA), anterior preserved angle (APA), and combined preserved angle (CPA)] before and after treatment were compared. Kaplan–Meier survival analysis and Cox regression analysis were used to identify the risk factors associated with femoral head collapse.

Result: Twenty-six males and 18 females with an average age of 38.3 ± 2.8 were followed for an average of 7.95 years. Forty-six of the 66 (69.7%) hips had no progression in pain or collapse, and patients exhibited a higher HHS (p < 0.05) after therapy. Twenty of the 66 (30.3%) hips progressed in Tonnis classification and ARCO stage, but only one of the 66 (1.5%) hips required total hip arthroplasty (THA). The Kaplan–Meier survivorship curve suggested that the survival rates were 96.97% at 5 years, 69.15% at 10 years, and 40.33% at 15 years. Patients with type A necrotic lesions on anteroposterior (AP) and frog-leg lateral (FLL) radiographs revealed 100% survival rates. Multivariate Cox regression analysis revealed that patients with an LPA ≤ 60.9 exhibited a 3.87 times higher risk of collapse of the femoral head [95% confidence interval (CI), 1.241–5.673] than did those patients with an LPA>60.9.

Conclusion: HXTL capsules could be a treatment option for ARCO stage II ONFH, resulting in improved hip function and delayed progression to femoral head collapse, especially when the anterior and lateral portions of the femoral head were not affected. However, an LPA of less than 60.9° may be a risk factor for collapse of the femoral head.

Clinical Trial Registration:http://www.chictr.org.cn/showproj.aspx?proj=10829, identifier ChiCTR-OPC-15007030

MiR-637 inhibits cell migration and invasion and promotes apoptosis in gastric cancer cells by targeting ERBB3

BACKGROUND

Previous studies have found that miR-637 can inhibit the invasion and migration of colon cancer, papillary thyroid carcinoma, glioma, and other tumor cells. It has also been found that miR-637 is down-regulated in gastric cancer (GC), but whether it affects the migration, invasion, and apoptosis of GC cells and the underlying molecular mechanisms are still not clear.

AIM

To investigate the effect of miR-637 on the migration, invasion, and apoptosis of GC cells and the underlying mechanisms.

METHODS

According to the treatments given, SGC-7901 cells (a GC cell line) were divided into miR-NC group, miR-637 group, anti-miR-NC group, anti-miR-637 group, si-NC group, si-ERBB3 group, miR-637 + pcDNA3.1 group, miR-637 + pcDNA3.1-ERBB3 group, miR-NC + WT-ERBB3 group, miR-NC + MUT-ERBB3 group, miR-637 + WT-ERBB3 group, and miR-637 + MUT-ERBB3 group. The expression of miR-637 was detected by qRT-PCR. Western blot was used to detect protein expression. Transwell assay was used to detect cell migration and invasion. Flow cytometry was used to detect apoptosis. Dual luciferase reporter gene assay was used to detect fluorescence activity.

RESULTS

Compared with tumor adjacent tissues, the expression of miR-637 was significantly decreased in GC tissues (P < 0.05). Overexpression of miR-637 and inhibition of ERBB3 expression inhibited the expression of matrix metalloproteinase 2 (MMP-2) and B cell lymphoma/leukemia-2 (Bcl-2), promoted the expression of epithelial cadherin (E-cadherin) and Bcl-2 associated X protein (Bax), suppressed the migration and invasion of SGC-7901 cells, and promoted apoptosis. MiR-637 can regulate the expression of ERBB3, and overexpression of ERBB3 can reverse the effect of miR-637 on the migration, invasion, and apoptosis of SGC-7901 cells.

CONCLUSION

MiR-637 can inhibit cell migration and invasion and promote apoptosis in SGC-7901 cells via mechanisms that may be related to down-regulation of ERBB3 expression, which will provide new targets for the prevention and treatment of GC.

Prophylactic Effects of Bifidobacterium adolescentis on Anxiety and Depression-Like Phenotypes After Chronic Stress: A Role of the Gut Microbiota-Inflammation Axis

Stress disturbs the balance of the gut microbiota and stimulates inflammation-to-brain mechanisms. Moreover, stress leads to anxiety and depressive disorders. Bifidobacterium adolescentis displays distinct anti-inflammatory effects. However, no report has focused on the anxiolytic and antidepressant effects of B. adolescentis related to the gut microbiome and the inflammation on chronic restraint stress (CRS) in mice. We found that pretreatment with B. adolescentis increased the time spent in the center of the open field apparatus, increased the percentage of entries into the open arms of the elevated plus-maze (EPM) and the percentage of time spent in the open arms of the EPM, and decreased the immobility duration in the tail suspension test as well as the forced swimming test (FST). Moreover, B. adolescentis increased the sequence proportion of Lactobacillus and reduced the sequence proportion of Bacteroides in feces. Furthermore, B. adolescentis markedly reduced the protein expression of interleukin-1β (IL-1β), tumor necrosis factor α (TNF-α), p-nuclear factor-kappa B (NF-κB) p65 and Iba1 and elevated brain derived neurotrophic factor (BDNF) expression in the hippocampus. We conclude that the anxiolytic and antidepressant effects of B. adolescentis are related to reducing inflammatory cytokines and rebalancing the gut microbiota.

HSC70 from Haemaphysalis flava (Acari: Ixodidae) exerts anticoagulation activity in vitro

Ticks and tick-borne diseases are major global health threats. During blood feeding, ticks insert their hypostomes into hosts and inject an array of anticoagulant molecules to maintain fluidity of the blood-meal. These anticoagulant molecules may provide insights into understanding the feeding biology of ticks and to develop vaccines against infestations. In Haemaphysalis flava, the heat shock cognate 70 (HSC70), a member of the heat shock protein (HSP) family, is differentially expressed in salivary glands at different levels of engorgement during blood feeding. However, its function in ticks is largely not known. The present study was designed to explore the possible effects of HSC70 on the plasma. The open reading frame (ORF) of HSC70 was expressed in a prokaryotic system, and recombinant HSC70 (rHSC70) was purified and characterized. The anticoagulation activity of rHSC70 was estimated by measuring prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT) and fibrinogen (FIB) with/without its inhibitor, VER155008. The results demonstrated that rHSC70 from H. flava extended TT (P < 0.001) and FIB clotting times (>300 s), but showed little effect on PT and APTT. Adding an inhibitor reversed anticlotting effects of rHSC70 on TT and FIB. These data indicate that rHSC70 is an anticoagulant agent, and the anticlotting activity likely attributes to the inhibition of thrombin and the transformation of fibrinogen into fibrin.

Proteomic profiling of the midgut contents of Haemaphysalis flava

Scant information is available regarding the proteins involved in blood meal processing in ticks. Here, we aimed to highlight the midgut proteins involved in preventing blood meal coagulation, and in facilitating intracellular digestion in the tick Haemaphysalis flava. Proteins were extracted from the midgut contents of fully engorged and partially engorged ticks. We used liquid chromatography tandem-mass spectrometry (LC-MS/MS) analysis to identify 131 unique peptides, and 102 proteins. Of these, 15 proteins, each with at least two unique peptides, were recognized with high confidence. We also retrieved 18 unigenes from our previous published transcriptomic libraries of the midguts and salivary glands of H. flava, and inferred the primary structures of nine proteins and fragments of five proteins. There were 23 and 21 unique proteins in the midgut contents of fully engorged and partially engorged ticks, respectively. We detected 58 shared proteins in the midgut contents of both fully engorged and partially engorged ticks. Of these, seven were significantly differentially expressed between fully engorged and partially engorged ticks: actin, calmodulin, elongation factor-1α, hsp90, multifunctional chaperone, tubulin α, and tubulin β. Our results demonstrated that the proteome of the midgut contents, combined with the transcriptome of the midgut, was a viable method for the reinforcement of protein identification. This method will facilitate further study of blood meal processing by ticks, as well as the identification of clues for tick infestation control. The existence of numerous proteins detected in the midgut contents also highlight the complexity of blood digestion in ticks; this area is in need of further investigation.

Aspirin increases metabolism through germline signalling to extend the lifespan of Caenorhabditis elegans

Aspirin is a prototypic cyclooxygenase inhibitor with a variety of beneficial effects on human health. It prevents age-related diseases and delays the aging process. Previous research has shown that aspirin might act through a dietary restriction-like mechanism to extend lifespan. To explore the mechanism of action of aspirin on aging, we determined the whole-genome expression profile of Caenorhabditis elegans treated with aspirin. Transcriptome analysis revealed the RNA levels of genes involved in metabolism were primarily increased. Reproduction has been reported to be associated with metabolism. We found that aspirin did not extend the lifespan or improve the heat stress resistance of germline mutants of glp-1. Furthermore, Oil Red O staining showed that aspirin treatment decreased lipid deposition and increased expression of lipid hydrolysis and fatty acid β-oxidation-related genes. The effect of germline ablation on lifespan was mainly mediated by DAF-12 and DAF-16. Next, we performed genetic analysis with a series of worm mutants and found that aspirin did not further extend the lifespans of daf-12 and daf-16 single mutants, glp-1;daf-12 and glp-1;daf-16 double mutants, or glp-1;daf-12;daf-16 triple mutants. The results suggest that aspirin increase metabolism and regulate germline signalling to activate downstream DAF-12 and DAF-16 to extend lifespan.

[Comparison on the efficacy and safety of different occlusion devices for the treatment of patients with patent foramen ovale]

Objective: To compare the efficacy and safety of Cardi-O-fix patent foramen ovale (PFO) occluder and Amplatzer PFO occluder for the treatment of patients with PFO. Methods: A total of 246 consecutive patients (105 males and 141 females) with PFO were prospectively enrolled from May 30, 2013 to March 30, 2015 in our hospital. PFO interventional closure was applied according to the anatomical structure of the disease and patients' wishes.Cardi-O-fix PFO occluder was used in 180 cases (COF group), Amplatzer PFO occluder was used in the remaining 66 cases (Amp group). Post-procedure safety including recurrent stroke, transient ischemic attack, death, and complete closure rate, and efficacy including procedure related complications of different devices were compared during the 12 months follow-up. Results: (1) Rate of transient ischemic attack was similar between COF group and Amp group at 12 months after procedure(1.1%(2/180) vs. 1.5%(1/66), P=1.000). There was no recurrent stroke and death during the 12 months follow-up period.Complete closure rate was similar between COF group and Amp group at 12 months after the procedure(90.6%(163/180)vs. 86.4%(57/66), P=0.355). (2) Three cases(1.7%) of paroxysmal atrial fibrillation were observed in COF group during the 12 months follow-up period, 1 patient converted spontaneously to sinus rhythm and 2 patients received successful pharmacologic conversion and converted to sinus rhythm. One patient(1.5%)developed paroxysmal atrial fibrillation and was pharmacologically converted to sinus rhythm in the Amp group. There was no significant difference in rate of paroxysmal atrial fibrillation between the two groups(P=1.000). There was no complications such as occluder translocation, erosion, pericardial effusion and puncture site bleeding in the 2 groups during the 12 months follow-up. Conclusion: Efficacy and safety are similar for PFO treatment with Cardi-O-fix PFO occluder or Amplatzer PFO occluder in this patient cohort.

Clinical efficacy of Weifuchun combined with quadruple therapy in treatment of chronic non-atrophic gastritis

AIM

To observe the curative effect of Weifuchun combined with quadruple therapy for Helicobacter pylori (H. pylori)-related chronic non-atrophic gastritis.

METHODS

A total of 196 chronic non-atrophic gastritis patients who tested positive for H. pylori were randomly divided into either a control group (n = 97; quadruple therapy alone) or a treatment group (n = 99; Weifuchun combined with quadruple therapy). The H. pylori eradication rates, gastroscopic and clinical curative effects were compared between the two groups.

RESULTS

The H. pylori eradication rate, gastroscopic and symptom total effective rates in the treatment group were 92.9%, 91.9% and 93.9%, respectively, which were significantly higher than those in the control group (83.5%, 84.5% and 85.6%, respectively; P < 0.05).

CONCLUSION

The curative effect of Weifuchun combined with quadruple therapy is superior to quadruple therapy in the treatment of H. pylori related chronic non-atrophic gastritis, and it can effectively improve H. pylori eradication rate.

[Chronic hypoxia increases intracellular Ca(2+) concentration and augments proliferation by enhancing store-operated Ca(2+) entry in pulmonary arterial smooth muscle cells]

OBJECTIVE

To determine whether store-operated Ca(2+) entry (SOCE) is involved in chronic hypoxia-induced alteration of intracellular Ca(2+) concentration ([Ca(2+) ]i) and proliferation in pulmonary arterial smooth muscle cells (PASMC).

METHODS

Rat PASMCs were cultured and treated in normoxia (21%O2) or hypoxia (4%O2) condition. The proliferation of PASMC was detected by cell counting kit-8 (CCK-8) assay. [Ca(2+) ]i, SOCE and the effects of store-operated Ca(2+) channel (SOCC) inhibitors, SKF96365 and NiCl2, on SOCE in hypoxic PASMCs were tested by InCyte [Ca(2+) ]i measurement system.

RESULTS

Hypoxia for 24-60 h augmented PASMC proliferation (1.12±0.09 vs 0.71±0.05, P<0.05) and [Ca(2+) ]i [(214.8 ± 20.4) nmol/L vs (115.2±13.2) nmol/L, P<0.05] in a time-dependent manner with the maximum effect at 60 h. Perfusion of Ca(2+) -free Krebs solution containing nifedipine (5 μmol/L), cyclopiazonic acid (CPA, 10 μmol/L) in PASMCs caused a small transient increase of [Ca(2+) ]i with peak [Ca(2+) ]i (113.3±49.3) nmol/L.Chronic hypoxia (4% O2, 60 h) enhanced [Ca(2+) ]i level with peak value of (193.2±22.7) nmol/L (P<0.05) in PASMC.After restoration of extracellular Ca(2+) , CPA caused marked increase of [Ca(2+) ]i with peak value of (328.0 ±56.7) nmol/L.Chronic hypoxia strengthened CPA-induced increase of [Ca(2+) ]i with peak value of (526.0±33.7) nmol/L (P<0.05) in PASMCs.Either SKF96365 50 μmol/L or NiCl2 500 μmol/L distinctly attenuated CPA-induced enhancement of [Ca(2+) ]i, the peak value of which dropped from (526.0±33.7) nmol/L to (170.4±26.4) nmol/L (P<0.05) or (177.4±45.9) nmol/L (P<0.05) respectively.

CONCLUSION

Chronic hypoxia boosts the release of Ca(2+) from sarcoplasmic reticulum and promotes the activity of SOCC and SOCE, leading to [Ca(2+) ]i elevation and proliferation of rat PASMCs.

High levels of glucose promote the activation of hepatic stellate cells via the p38-mitogen-activated protein kinase signal pathway

The relationship between the p38-mitogen-activated protein kinase (p38-MAPK) signal pathway and high glucose-induced hepatic stellate cell (HSC) activation was investigated in this study. Sixty human HSC samples were randomly selected and used in the control (cultured normally), high-glucose (cultured in the presence of high glucose), and blocking (cultured under high-glucose conditions in the presence of the p38-MAPK inhibitor, SB203580) groups. The cells were incubated for 120 h and subsequently analyzed for morphological changes by inverted microscopy and for a-smooth muscle actin (a-SMA) expression (to determine the degree of HSC activation) by the method of streptavidin-biotin complex and western blot. Phospho-p38-MAPK protein expression was analyzed by western blotting. a-SMA and phospho-p38-MAPK expression was significantly upregulated in HSCs cultured under high-glucose conditions, compared to the HSCs cultured normally (P < 0.01). On the other hand, phospho-p38-MAPK and a-SMA protein levels were significantly lower in the blocking group compared to the high-glucose group (P < 0.01). Based on these results, we concluded that high-glucose levels induce HSC activation mediated by phospho-p38-MAPK. Therefore, blocking the p38-MAPK signal pathway could inhibit this effect.

Clinicopathological features of invasive lobular carcinoma of the breast: A nationwide multicenter study in China

OBJECTIVE

To analyze the clinicopathological features of invasive lobular carcinoma (ILC) and compare them with invasive ductal carcinoma (IDC), hoping to find the fact of ILC in China and assist the decision makers with proper individualized treatment.

MATERIALS AND METHODS

A nationwide multicenter retrospective study was performed. A total of 4211 primary breast cancer cases were randomly selected from 1999 to 2008 in seven regions of China. ILC cases were compared with IDC by clinicopathological features and molecular subtypes.

RESULTS

A total of 135 (3.2%) ILC and 3471 (82.4%) IDC cases were included for analysis. The age, tumor size, menopausal state, family history, nodal status, and stage of ILC were similar to that of IDC. ILC was more likely to be positive for estrogen receptor (65.5% vs. 57.7%) and progesterone receptor (64.7% vs. 58.5%), and less likely to overexpress human epidermal growth factor receptor-2 (17.3% vs. 23.6%). Even though, these differences are not significant, the proportion of luminal A type of ILC is significantly larger than that of IDC (54.8% vs. 42.7%; P < 0.05).

CONCLUSION

ILC has a larger proportion of luminal A type compared with IDC. Larger sample size study for better known of molecular subtypes of ILC is needed in future to individualize the treatment decision.

Characterization of chicken natural resistance-associated macrophage protein encoding genes (Nramp1 and Nramp2) and association with salmonellosis resistance

Natural resistance-associated macrophage protein 1 and 2 encoding genes (Nramp1 and Nramp2) are related to many diseases. We cloned the cDNA of chicken Nramp1 and Nramp2 genes, characterized their expression and polymorphisms, and investigated the association of some SNPs with resistance to salmonellosis. The Nramp1 cDNA was 1746 bp long and the Nramp2 cDNA was 1938 bp long. These cDNAs are similar to previously reported cDNAs, varying by two and one amino acids, respectively. The chicken Nramp1 gene expressed predominantly in liver, thymus and spleen in both females and males. The Nramp2 gene expressed in almost all tissues, but predominantly in breast muscle, leg muscle, cerebrum, cerebellum, lung, kidney, and heart in both females and males. We identified 45 SNPs and 2 indels in the chicken Nramp1 gene; three of 13 SNPs in the exons were missense mutations (Arg223Gln, Ala273Glu and Arg497Gln). Association analysis indicated that A24101991G is significantly associated with chicken salmonellosis resistance. These results will be useful for functional investigation of chicken Nramp1 and Nramp2 genes.

Development of a fluorescent-intercalating-dye-based reverse transcription loop-mediated isothermal amplification assay for rapid detection of seasonal Japanese B encephalitis outbreaks in pigs

The standardization and validation of a one-step, single-tube, accelerated fluorescent-intercalating-dye-based reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay targeting the NS3 gene of Japanese B encephalitis virus (JEV) is described for rapid, simple, and high-throughput detection of JEV. The amplification can be completed in 35 min under isothermal conditions at 63°C by employing a set of six primers targeting the NS3 gene of JEV. The RT-LAMP assay described demonstrated high sensitivity for detecting JEV, with a detection limit in swine samples of 8.13 PFU/ml. The specificity of the selected primer sets was established by cross-reactivity studies with pathogens that exhibit similar clinical signs and testing of samples from healthy animals. The clinical applicability of the RT-LAMP assay was validated using either spiked samples or samples from seasonal outbreaks. The comparative evaluation of the RT-LAMP assay revealed 79.59 % concordance with conventional RT-PCR targeting the E gene of JEV. The RT-LAMP assay reported here is a valuable tool for rapid real-time and high-throughput seasonal infection surveillance and quarantine after outbreak through blood sampling by using ordinary real-time PCR thermocyclers without purchasing an expensive Loopamp real-time turbidimeter.

Genetic association between low-density lipoprotein receptor-related protein gene polymorphisms and Alzheimer's disease in Chinese Han population

Alzheimer's disease (AD) is the most common neurodegenerative disorders in the elderly. Low-density lipoprotein receptor-related protein (LRP), as a receptor of apolipoprotein E (APOE), APP, and alpha2 macroglobulin (alpha2-M), keeps the balance between degeneration and production of beta-amyloid protein (Abeta) clearance. Its gene had been defined as a candidate gene for AD, but the results were not universal. Total 496 AD patients and 478 controls were recruited in Chinese Han population and real-time PCR was used to detect the polymorphism of LRP C766T. Multiple logistic regression, Chi-square test and survival analysis were performed to explore the association. The distribution of LRP genotypes and alleles was significantly different between cases and controls, and T allele could reduce the risk for developing AD (OR of CT genotype: 0.57; 95% CI: 0.38-0.85, rho=0.003; OR of T allele: 0.57; 95% CI: 0.39-0.83, rho=0.003). TT genotype carriers had 5 years later for developing AD compared with CC genotype carriers, but survival analysis did not conform this (LRP TT vs. CT and CC log rank chi(2)=2.71, rho=0.26). The distribution of LRP C766T genotypes and alleles was different among different severity stratified by MMSE yet (rho=0.26). Our data suggested that the polymorphism of LRP C766T was strongly associated with AD and T allele might be a protective factor for AD in Chinese Han population.

[Electroanalytical characteristics of ofloxacin in micellar solution]

In a pH 6.30 buffer solution containing 0.001% Tween-80, ofloxacin (OFX) gives a sensitive polarographic wave at -1.46 V (vs SCE), which can be used for the determination of OFX down to 10(-8) mol.L-1. The linear range is from 1.39 x 10(-7) to 1.39 x 10(-5) mol.L-1. The proposed method was applied to determination of OFX in urine and serum samples with relative standard deviation less than 7.0%.

Cloning and expression of the human tumor-specific antibody GM4

The human monoclonal antibody GM4 was generated by fusing pooled lymphocytes from cancer patients with the lymphoblastoid cell line SHFP-1. Immunohistochemical staining of tumor and normal tissue indicated that this human IgG4 antibody preferentially reacted with melanomas and neuroblastomas. In this study, we demonstrate that GM4 recognizes a "vimentin-like" peptide sequence that we have termed AgGM4. To generate a recombinant derivative of this human antibody, we isolated and expressed the complete heavy and light chain genes. The entire coding sequence for both the heavy and light chains was isolated by RT-PCR using a set of degenerate 5' signal sequence specific primers and a 3' constant region primer. High level antibody synthesis and secretion was achieved in Chinese hamster ovary (CHO) cells using a vector designed to maximize expression. Western blot and FACS analysis indicated recombinant GM4 reacted with human tumor cell lines and AgGM4 in a manner similar to the antibody produced by the hybridoma cell line, demonstrating that the specificity of the antibody was not altered during molecular cloning.

Automated percutaneous lumbar discectomy: a prospective multi-institutional study

PURPOSE

A prospective study in 10 independent hospitals from 1992 to 1994 evaluated automated percutaneous lumbar discectomy (APLD) with a newly designed percutaneous instrument.

MATERIALS AND METHODS

One thousand five hundred eighty-two APLD procedures were performed in 1,525 patients with disc herniation or back pain. Mean follow-up after APLD was 18.3 months. Follow-up of at least 1 year was available in 1,474 patients. One thousand two hundred eighty-nine patients had sciatic pain and 185 had back pain only. Eight hundred twenty-two patients had symptoms for less than 2 years, 652 for more than 2 years. One thousand two hundred sixty-two patients were older than 60 years, 212 were younger than 60 years. Nine hundred fifty patients had disc protrusion, and 357 had sequestration. Forty-eight patients had disc or longitudinal ligament calcification. Twenty-two had previous surgical discectomy. All discectomies were done with use of a straight needle with the patient in the lateral decubitus position.

RESULTS

Success rate (measured by Hijikata's criteria) was 83% at 1 year. Success was significantly greater for protrusion versus sequestration (86% vs 72%, P < .001); for back pain alone versus leg and back pain (89% vs 80%, P < .005); for duration of symptoms less than 2 years versus more than 2 years (85% vs 79%, P < .005); and for age younger than 60 years versus older than 60 years (84% vs 76%, P < .01). Among postsurgical patients, success rate was 77% (17 of 22 patients). The only complication was discitis (0.06%, nine patients). Technical success at L5-S1 was 99% (795 of 800).

CONCLUSION

APLD with Teng's instrument has excellent results. Indications may include back pain alone. A straight needle can be used at L5-S1 in most patients, with proper positioning.

High resolution structures of the 4-4-20 Fab-fluorescein complex in two solvent systems: effects of solvent on structure and antigen-binding affinity

Three-dimensional structures were determined for three crystal forms of the antigen binding fragment (Fab) of anti-fluorescein antibody 4-4-20 in complex with fluorescein. These included 1) a triclinic (P1) form crystallized in 47% (v/v) 2-methyl-2,4-pentanediol (MPD); 2) a triclinic (P1) form crystallized in 16% (w/v) poly(ethylene glycol), molecular weight 3350 (PEG); and 3) a monoclinic (P21) form crystallized in 16% PEG. Solvent molecules were added to the three models and the structures were refined to their diffraction limits (1.75-A, 1.78-A, and 2.49-A resolution for the MPD, triclinic PEG, and monoclinic PEG forms, respectively). Comparisons of these structures were interesting because 4-4-20 exhibited a lower antigen-binding affinity in 47% MPD (Ka = 1.3 x 10(8) M-1) than in either 16% PEG (Ka = 2.9 x 10(9) M-1) or phosphate-buffered saline (Ka = 1.8 x 10(10) M-1). Even though the solution behavior of the antibody was significantly different in MPD and PEG, the crystal structures were remarkably similar. In all three structures, the fluorescein-combining site was an aromatic slot formed by tyrosines L32, H96, and H97 and tryptophans L96 and H33. In addition, several active site constituents formed an electrostatic network with the ligand. These included a salt link between arginine L34 and one of fluorescein's enolate oxygen atoms, a hydrogen bond between histidine L27d and the second enolic group, a hydrogen bond between tyrosine L32 and the phenylcarboxylate group, and two medium range (approximately 5 A) electrostatic interactions with lysine L50 and arginine H52. The only major difference between the triclinic MPD and PEG structures was the degree of hydration of the antigen-combining site. Three water molecules participated in the above electrostatic network in the MPD structure, while eight were involved in the PEG structure. Based on this observation, we believe that 4-4-20 exhibits a lower affinity in MPD due to the depletion of the hydration shell of the antigen-combining site.

Internal vibrations of a molecule consisting of rigid segments. I. Non-interacting internal vibrations

For molecular crystals, a procedure is proposed for interpreting experimentally determined atomic mean square anisotropic displacement parameters (ADPs) in terms of the overall molecular vibration together with internal vibrations with the assumption that the molecule consists of a set of linked rigid segments. The internal librations (molecular torsional or bending modes) are described using the variable internal coordinates of the segmented body. In paper I of this two-part report, it is assumed as a zero-order approximation that the internal vibrations about the linkage axes between pairs of segments are uncorrelated with each other and with the overall molecular rigid-body vibrations. As a first-order approximation, the possibility that each internal vibration can be correlated with the external vibrations is also considered. An important feature of this approach is that the internal librations are required to give zero contribution to the overall momentum of the molecule at all times, so the internal coordinates must be orthogonal to the external ones. Also, each of the internal librations involves the motion of all atoms in the molecule. The resulting internal vibrational parameters are invariant to the choice of reference segment. With this procedure, the experimental ADPs obtained from crystal structure determinations involving six small molecules (sym-trinitrobenzene, adenosine, tetra-cyanoquinodimethane, benzamide, alpha-cyanoacetic acid hydrazide and N-acetyl-L-tryptophan methylamide) have been analyzed. As a consequence, vibrational corrections to the bond lengths and angles of the molecule are calculated as well as the frequencies and force constants (with e.s.d.'s) for each internal torsional or bending vibration. Compared with other models used for describing internal vibrations, there are differences in how the total ADP is partitioned between the internal and overall molecular vibrations.

Three-dimensional structure of an Fv from a human IgM immunoglobulin

An IgM(kappa) immunoglobulin from a patient (Pot) with Waldenstrom's macroglobulinemia was hydrolyzed with pepsin to release a fragment consisting of the 'variable' (V) domains of the light and heavy chains plus eight residue 'tails' from the 'constant' (C) domains. The crystal structure of this fragment was determined at 2.3 A resolution by molecular replacement and crystallographic refinement methods. When examined separately, the light chain component closely resembles another human kappa chain (Rei) in both the beta-pleated sheet regions and the 'hypervariable' loops. The conserved pleated sheets in the heavy chain are similar to those in the human Kol IgG1 protein, but the third hypervariable loop in particular is different from that in any immunoglobulin structure described to date. As in the Kol protein, this loop blocks the access to any internal active site along the light-heavy chain interface. Unlike the Kol protein, however, the loop does not protrude beyond the boundaries of a conventional antigen combining site. Instead, it forms a very compact structure, which fills almost all residual space between the domains. This is an example of one dominant complementarity-determining region (CDR) essentially negating the diversity possible with five other CDRs in the two chains. Ordered water molecules are associated with light chain constituents along the interface, but not with CDR3 of the heavy chain. In screening exercises the Pot IgM failed to bind a wide variety of peptides. Together, the results suggest that ligand binding can only occur on external surfaces of the protein. These surfaces carry a limited number of side chains usually assigned to CDRs in more typical antibodies.

Structure of a human monoclonal antibody Fab fragment against gp41 of human immunodeficiency virus type 1

The three-dimensional structure of a human monoclonal antibody (Fab), which binds specifically to a major epitope of the transmembrane protein gp41 of the human immunodeficiency virus type 1, has been determined by crystallographic methods to a resolution of 2.7 A. It has been previously determined that this antibody recognizes the epitope SGKLICTTAVPWNAS, belongs to the subclass IgG1 (kappa), and exhibits antibody-dependent cellular cytotoxicity. The quaternary structure of the Fab is in an extended conformation with an elbow bend angle between the constant and variable domains of 175 degrees. Structurally, four of the hypervariable loops can be classified according to previously recognized canonical structures. The third hypervariable loops of the heavy (H3) and light chain (L3) are structurally distinct. Hypervariable loop H3, residues 102H-109H, is unusually extended from the surface. The complementarity-determining region forms a hydrophobic binding pocket that is created primarily from hypervariable loops L3, H3, and H2.

Atomic structure and chemistry of human serum albumin

The three-dimensional structure of human serum albumin has been determined crystallographically to a resolution of 2.8 A. It comprises three homologous domains that assemble to form a heart-shaped molecule. Each domain is a product of two subdomains that possess common structural motifs. The principal regions of ligand binding to human serum albumin are located in hydrophobic cavities in subdomains IIA and IIIA, which exhibit similar chemistry. The structure explains numerous physical phenomena and should provide insight into future pharmacokinetic and genetically engineered therapeutic applications of serum albumin.

Expression of O6-methylguanine-DNA methyltransferase in six human medulloblastoma cell lines

Six well characterized human medulloblastoma cell lines (D283 Med, Daoy, D341 Med, D384 Med, D425 Med, and D458 Med) were examined for the expression of O6-methylguanine-DNA methyltransferase (MGMT) by activity and Western and Northern blot analysis. High levels of MGMT activity were present in D283 Med, Daoy, D341 Med, and D384 Med (1.36, 0.80, 1.68, and 1.62 pmol/mg of protein, respectively), but negligible MGMT activity was detected in D425 Med and D458 Med (0.06 and 0.05 pmol/mg of protein, respectively), which were derived separately at different times from the same patient. The presence of MGMT protein and its transcript was demonstrated in D283 Med, Daoy, D341 Med, and D384 Med, but both the protein and the mRNA were undetectable in D425 Med and D458 Med. Nevertheless, all six cell lines contained an apparently unaltered MGMT gene, as determined by Southern blot analysis. The absence of MGMT activity in D425 Med and D458 Med is likely due to the absence of the protein, resulting from a lack of transcription of the MGMT gene. The varying levels of expression of MGMT in medulloblastoma cells found in this study should provide a molecular basis for drug design and selection in chemotherapy of this tumor.

Occurrence of lacto series gangliosides 3'-isoLM1 and 3',6'-isoLD1 in human gliomas in vitro and in vivo

Monoclonal antibodies (MAb; DMAb, monoclonal antibodies derived at Duke Medical Center) directed against the oncofetally expressed lactotetraosyl gangliosides 3'-isoLM1 (IV3NeuAc-LcOse4Cer) and 3',6'-isoLD1 (IV3NeuAc,III6NeuAc-LcOse4Cer) were produced and their reactivity spectra compared to that of the alpha-3'-isoLM1 MAb SL-50. The IgM MAb SL-50 defines the epitope NeuAc (or NeuGc)alpha 2-3Gal beta 1-3GlcNAc, the terminal sequence of both gangliosides. SL-50 requires an unsubstituted GlcNAc residue; IgM DMAb-14 will accept the alpha 2-6 linked sialic acid to GlcNAc found in 3',6'-isoLD1. Immunohistochemical localization of 3'-isoLM1 was performed on 31 biopsy specimens of human gliomas; 15 (48%) expressed 3'-isoLM1 as defined by binding of MAb SL-50. Staining of small anaplastic cells, giant cells, and the glial component of gliosarcomas was observed. Neoplastic gemistocytes, when present, showed particularly intense staining. The 3'-isoLM1 and 3',6'-isoLD1 distribution in cultured cell lines and derived xenografts of primary tumors of the human central nervous system and of embryonal or neuroectodermal tumor derivation was determined. Six of 29 cell lines expressed 3'-isoLM1: 2/16 gliomas, 3/3 teratomas, 1/1 pancreatic adenocarcinoma. No cell line expressed detectable 3',6'-isoLD1 by immunostain analysis of ganglioside extracts. The 3'-iso-LM1-positive cell lines expressed it in xenograft form; in five xenografts, the corresponding cell lines of which were 3'-isoLM1-negative, it was a proportion of the monosialoganglioside fraction. 3',6'-isoLD1 was detected in two xenografts, D-54 MG (glioma) and PA-1 (teratoma). The demonstration of 3'-isoLM1 in gliomas in in vivo forms and the relatively infrequent expression by derived cultured cells suggest that ganglioside expression is modified by environmental forces. Expression of 3'-isoLM1 and 3',6'-isoLD1 in fetal and neonatal brain, in intense reactive astrocytosis such as polyunsaturated fatty acid lipidosis, and in primary neoplasms of the central nervous system suggests their role in cell-cell attachment during development, migration, and neoplastic transformation.

An autoantibody to single-stranded DNA: comparison of the three-dimensional structures of the unliganded Fab and a deoxynucleotide-Fab complex

Crystal structures of the Fabs from an autoantibody (BV04-01) with specificity for single-stranded DNA have been determined in the presence and absence of a trinucleotide of deoxythymidylic acid, d(pT)3. Formation of the ligand-protein complex was accompanied by small adjustments in the orientations of the variable (VL and VH) domains. In addition, there were local conformational changes in the first hypervariable loop of the light chain and the third hypervariable loop of the heavy chain, which together with the domain shifts led to an improvement in the complementarity of nucleotide and Fab. The sugar-phosphate chain adopted an extended and "open" conformation, with the base, sugar, and phosphate components available for interactions with the protein. Nucleotide 1 (5'-end) was associated exclusively with the heavy chain, nucleotide 2 was shared by both heavy and light chains, and nucleotide 3 was bound by the light chain. The orientation of phosphate 1 was stabilized by hydrogen bonds with serine H52a and asparagine H53. Phosphate 2 formed an ion pair with arginine H52, but no other charge-charge interactions were observed. Insertion of the side chain of histidine L27d between nucleotides 2 and 3 resulted in a bend in the sugar-phosphate chain. The most dominant contacts with the protein involved the central thymine base, which was immobilized by cooperative stacking and hydrogen bonding interactions. This base was intercalated between a tryptophan ring (no. H100a) from the heavy chain and a tyrosine ring (no. L32) from the light chain. The resulting orientation of thymine was favorable for the simultaneous formation of two hydrogen bonds with the backbone carbonyl oxygen and the side chain hydroxyl group of serine L91 (the thymine atoms were the hydrogen on nitrogen 3 and keto oxygen 4).

Production and characterization of antipeptide antibodies against human O6-methylguanine-DNA methyltransferase

Four synthetic peptides from the sequence of human O6-methylguanine-DNA methyltransferase (MGMT), three corresponding to different hydrophilic regions and one corresponding to the sequence containing the alkyl acceptor residue cysteine 145, were used to immunize rabbits. The antibody against Peptide III (residues 171-184) was highly specific, and MGMT protein could be detected on Western blots of soluble protein extracts containing as little as 1 fmol of active MGMT. Antibodies against all of the peptides were able to immunoprecipitate denatured MGMT, while only the antibody against Peptide III was able to react with active enzyme. The antibody against Peptide III did not cross-react with methyltransferase from mice. The use of synthetic peptides has led to the production of a highly sensitive, specific antibody that recognizes native and denatured human MGMT. This antibody should prove useful in studies involving the detection, purification, and characterization of this enzyme.

Differentiation characteristics of newly established medulloblastoma cell lines (D384 Med, D425 Med, and D458 Med) and their transplantable xenografts

Three new human medulloblastoma (MB) cell lines (D384 Med, D425 Med, and D458 Med) and their transplantable xenografts were examined for antigenic expression with antibodies against neuroectodermal antigens, cytoskeletal proteins, neuroendocrine markers, glioma-associated antigens, tenascin, human lymphocyte antigen molecules, epidermal growth factor receptor, and T-cell antigen by indirect immunofluorescence, avidin-biotin complex peroxidase immunohistochemistry, and immunoblot methods. We found that each of the three cell lines expressed vimentin; low-, middle-, and high-molecular-weight neurofilament proteins; and the synaptic vesicle membrane glycoprotein synaptophysin. Each of the cell lines also reacted with antibodies against neural cell adhesion molecules, but none of them were positive for antibodies against glial fibrillary acidic protein, keratin, microtubule-associated protein tau and microtubule-associated protein 2, human lymphocyte antigen-DR, epidermal growth factor receptor, and T-cell antigen. Immunoreactivities with anti-tenascin and anti-glioma-associated antibodies were variable in these cell lines. Anti-human lymphocyte antigen-A,B and anti-beta 2-microglobulin antibodies reacted with xenografts of D384 Med and D425 Med and were weakly positive for a small population of D384 Med cultured cells. In summary, the detection of neurofilament proteins and synaptophysin and the absence of glial fibrillary acidic protein provide strong evidence for a neuronal phenotype of D384 Med, D425 Med, and D458 Med.

Crystallization of the Fab from a human monoclonal antibody against gp 41 of human immunodeficiency virus type I

A monoclonal IgG antibody directed against gp 41 from the human immunodeficiency virus (HIV-1) has been crystallized in both intact and Fab forms. Crystals of the intact antibody grow as tetragonal-like prisms too small for conventional X-ray analysis. However, the Fab portion of the antibody produces suitable plate-like crystals which belong to the space group P2(1)2(1)2(1) with unit cell constants of a = 66.5 A, b = 74.3 A and c = 105.3 A. There is one molecule of Fab in the asymmetric unit. The Fab crystals show diffraction to d-spacings less than 3.0 A.

Time-dependent inhibition of oxygen radical induced lung injury

Experimental acute lung injury mediated by reactive metabolites of oxygen can be inhibited by the antioxidant enzymes catalase and superoxide dismutase (SOD). However, the specific time interval during which these enzymes must be present in order to cause protection is not well defined. Using two experimental models of oxidant-dependent acute lung injury, one involving the intratracheal injection of glucose, glucose oxidase, and lactoperoxidase and the other involving the intravenous injection of cobra venom factor (CVF), we investigated the effects of delaying antioxidant administration on the outcome of the inflammatory response. In both cases, the protective effects of catalase and SOD were rapidly attenuated when their administration was delayed for a short period of time. For example, intratracheal catalase resulted in 98% protection when given simultaneously with the glucose oxidase and lactoperoxidase, but only 13% protection when the catalase was delayed 4 min. Likewise, in the CVF-induced lung injury model, intravenous catalase resulted in 40% protection when given simultaneously with the CVF, but only 2% protection when the catalase was delayed 20 min, even though the peak of the injury occurred hours after the initiation of the injury. A similar time dependence was seen with SOD. These results indicate that antioxidant therapy is required early in the course of oxygen radical-mediated acute lung injury for effective protection.

Preliminary crystallographic examination of a novel fungal lysozyme from Chalaropsis

The lysozyme from the fungus of the Chalaropsis species has been crystallized. This lysozyme (Mr 22,415) displays no sequence homology with avian, phage, or mammalian lysozymes, however, preliminary studies indicate significant sequence homology with the bacterial lysozyme from Streptomyces. Both enzymes are unusual in possessing beta-1,4-N-acetylmuramidase and beta-1,4-N,6-O-diacetylmuramidase activity. The crystals grow from solutions of ammonium sulfate during growth periods from several months to a year. The space group is P2(1)2(1)2(1) with a = 34.0 A, b = 42.6 A, c = 122.1 A. Preliminary data indicate that there is 1 molecule/asymmetric unit. A complete native data set has been collected to 2.57-A resolution. The crystals are highly ordered and exhibit diffraction patterns to d-spacings less than 1.5 A.

Synthetic site-directed ligands

Complexes of nucleotides, peptides and aromatic hapten-like compounds with immunoglobulin fragments were studied by X-ray analysis. After tri- or hexanucleotides of deoxythymidylate were diffused into triclinic crystals of a Fab (BV04-01) with specificity for single-stranded DNA, extensive changes were detected throughout the structure of the protein. The Fab co-crystallized with a tri- or pentanucleotide in a different space group (monoclinic), an observation sometimes correlated with alterations in the structure of the 'native' protein. Structural analyses of the co-crystals are in progress for direct comparisons with the unliganded Fab. In crystals of a human (Mcg) Bence-Jones dimer, synthetic opioid peptides, chemotactic peptides or dinitrophenyl (DNP) derivatives could be diffused into a large conical binding cavity. The conformations of both the ligand and the protein were usually altered during the binding process. At the base of the cavity tyrosine residues could be displaced like trap-doors to permit entry of some opioid peptides and DNP compounds into a deep binding pocket. In co-crystals of the dimer and bis(DNP)lysine, two ligand molecules were bound in tandem, one in the main cavity and the second in the deep pocket. One ligand adopted an extended conformation, with the epsilon-DNP ring near the floor of the main cavity and the alpha-DNP group in solvent outside the binding site. There were no significant conformational changes in the protein. In contrast, the second ligand was very compact, with DNP rings immersed in the deep pocket, and the binding site was expanded to accommodate the oversized ligand. Peptides designed to be specific for the main cavity were incrementally constructed from minimal binding units by M. Geysen, G. Trippick, S. Rodda and their colleagues. A pentapeptide optimized for binding by this method was diffused into a crystal of the dimer and found by Fourier difference analysis to lodge exclusively in the main cavity as predicted. Binding regions in the BV04-01 Fab and the Mcg dimer were markedly different in size and shape. The Fab had a groove-type site, in which a layer of sidechains acted like a false floor over regions analogous to the cavity and deep pocket of the Bence-Jones dimer.

Three-dimensional structure of human serum albumin

The three-dimensional structure of human serum albumin has been solved at 6.0 angstrom (A) resolution by the method of multiple isomorphous replacement. Crystals were grown from solutions of polyethylene glycol in the infrequently observed space group P42(1)2 (unit cell constants a = b = 186.5 +/- 0.5 A and c = 81.0 +/- 0.5 A) and diffracted x-rays to lattice d-spacings of less than 2.9 A. The electron density maps are of high quality and revealed the structure as a predominantly alpha-helical globin protein in which the course of the polypeptide can be traced. The binding loci of several organic compounds have been determined.

Cocrystallization of an immunoglobulin light chain dimer with bis(dinitrophenyl) lysine: tandem binding of two ligands, one with and one without accompanying conformational changes in the protein

Previous studies showed that the Mcg dimer of immunoglobulin light chains bound bis(dinitrophenyl)lysine both in trigonal crystals and in solution. On prolonged storage in ammonium sulfate, mixtures of ligand and protein produced small trigonal cocrystals in low frequency. These crystals were nearly isomorphous with those of the unliganded dimer in which the subunits were covalently linked by an interchain disulfide bond. By difference Fourier analyses at 3.5 A resolution and subsequent crystallographic refinement, the cocrystals were found to contain molecules with two ligands aligned in tandem along the interface of the variable (V) domains of the protein. One ligand molecule adopted an almost fully extended conformation, with the epsilon-DNP ring situated near the floor, the alpha-carboxyl group directed toward the solvent at the entry, and the alpha-DNP ring outside the rim of the main cavity. As if architecturally designed, the ligand was located symmetrically between the two domains in an orientation that was compatible with both the unaltered structure of the cavity lining and with the known crystal packing interactions of neighboring protein molecules. The second ligand molecule in the cocrystal lodged in the deep pocket immediately under the floor of the main cavity. The ligand adopted a very compact conformation with the two DNP rings roughly antiparallel to each other. This molecule appeared to be semi-permanently sequestered in the pocket since it could not be dislodged by exhaustive perfusion with ammonium sulfate crystallizing media. Relative to its volume in the native dimer, the pocket was expanded to accommodate the oversized ligand. Within a single protein molecule, therefore, two types of binding of a flexible ligand were observed, one with and one without accompanying conformational changes in the protein. The number of cocrystals which could be produced was markedly increased if the interchain disulfide bond between the Mcg monomers was first reduced and alkylated.

Phenotypic analysis of four human medulloblastoma cell lines and transplantable xenografts

An extensive panel of monoclonal antibodies (MAb) and monospecific antisera reactive against neuroectodermal-, neuronal-, glial-, and lymphoid-associated antigens, extracellular matrix, HLA, and cell-surface receptors was used to characterize the phenotype of four continuous, karyotypically distinct medulloblastoma cell lines and transplantable xenografts. All four cell lines demonstrated significant reactivity with anti-neuroectodermal-associated MAb. No apparent pattern of reactivity with anti-lymphoid MAb was seen; notably, there was a uniform absence of detectable Thy-1. Review of the complete antibody reactivity profile revealed a dichotomy between lines TE-671 and Daoy and lines D283 Med and D341 Med, which have been previously shown to express neurofilament protein in culture and xenografts, and to exhibit neuroblastic morphological features in biopsy and xenograft tissue sections. TE-671 and Daoy reacted with the MAb directed against tenascin, epidermal growth factor (EGF) receptor, HLA-A,B epitopes, beta 2-microglobulin and 5/8 of the glioma-associated antigens, but did not react with the anti-neurofilament protein (NFP) MAb. D283 Med and D341 Med expressed NFP but did not react with MAb against tenascin, EGF receptor, HLA-A,B epitopes, beta 2-microglobulin or 6/8 and 7/8 (respectively) of the glioma-associated antigens. The observed phenotypic differences provide a conceptual framework for investigating basic differences in the biological behavior of medulloblastoma. Moreover, the subdivisions can be evaluated for prospective value in tissue diagnosis, cerebrospinal fluid cytology and antibody-mediated imaging and therapy.

Three-dimensional structure of a fluorescein-Fab complex crystallized in 2-methyl-2,4-pentanediol

The crystal structure of a fluorescein-Fab (4-4-20) complex was determined at 2.7 A resolution by molecular replacement methods. The starting model was the refined 2.7 A structure of unliganded Fab from an autoantibody (BV04-01) with specificity for single-stranded DNA. In the 4-4-20 complex fluorescein fits tightly into a relatively deep slot formed by a network of tryptophan and tyrosine side chains. The planar xanthonyl ring of the hapten is accommodated at the bottom of the slot while the phenylcarboxyl group interfaces with solvent. Tyrosine 37 (light chain) and tryptophan 33 (heavy chain) flank the xanthonyl group and tryptophan 101 (light chain) provides the floor of the combining site. Tyrosine 103 (heavy chain) is situated near the phenyl ring of the hapten and tyrosine 102 (heavy chain) forms part of the boundary of the slot. Histidine 31 and arginine 39 of the light chain are located in positions adjacent to the two enolic groups at opposite ends of the xanthonyl ring, and thus account for neutralization of one of two negative charges in the haptenic dianion. Formation of an enol-arginine ion pair in a region of low dielectric constant may account for an incremental increase in affinity of 2-3 orders of magnitude in the 4-4-20 molecule relative to other members of an idiotypic family of monoclonal antifluorescyl antibodies. The phenyl carboxyl group of fluorescein appears to be hydrogen bonded to the phenolic hydroxyl group of tyrosine 37 of the light chain. A molecule of 2-methyl-2,4-pentanediol (MPD), trapped in the interface of the variable domains just below the fluorescein binding site, may be partly responsible for the decrease in affinity for the hapten in MPD.

Thermal vibrations and electrostatic properties of parabanic acid at 123 and 298 K

The crystal structure of parabanic acid (1H,3H-imidazoletrione, C3H2N2O3, Mr = 114.1) at 123 K [monoclinic, P2(1)/n, Z = 4, a = 10.704 (2), b = 8.187 (2), c = 4.969 (1) A, beta = 92.32 (1)o] has been determined by neutron and X-ray diffraction. Neutron reflections [1658, (sin theta)/lambda less than or equal to 0.78 A-1, lambda = 1.0470 (1) A, mu = 0.75 cm-1] in full-matrix least-squares refinement (wR = 0.055) gave nuclear parameters with bond lengths having estimated standard deviations (e.s.d.'s) of 0.001 A. X-ray reflections [3150 with magnitude of F magnitude of greater than or equal to 3 sigma and (sin theta)/lambda less than or equal to 1.3 A-1, Mo Ka, lambda = 0.7093 (1) A, mu = 1.708 cm-1] were used in full-matrix least-squares refinement (R = 0.022) assuming Stewart's rigid pseudoatom model, so as to determine the charge-density distribution. Sharp features near the O nuclei in the residual electron density map noted by Craven & McMullan (CM) [Acta Cryst. (1979), B35, 934-945] in their 298 K study were absent at 123 K. New refinements using CM's 298 K data give significant third-order thermal parameters for O atoms due to anharmonic molecular stretching, with good agreement between probability density functions, (p.d.f.'s) from X-ray and neutron diffraction. When deconvoluted from the thermal vibrations in the crystal, deformation charge densities derived at 298 and 123 K are in satisfactory agreement and conform closely to the 2 mm symmetry of the isolated molecule. The molecular dipole moment is 2.3 (3) D [7.7 (10) x 10(-30) C m]. A map of molecular electrostatic potential indicates that the carbonyl O atoms in parabanic acid are weakly electronegative. This is confirmed by calculation of the electrostatic energy of interaction for the two distinct H-bonded pairs of molecules isolated from the crystal. Energy values are weakly attractive [-7 (3) and 5 (2) kJ mol-1]. Similar calculations are less reliable for pairs of molecules forming intermolecular C....O distances as short as 2.75 A. However, depending on the model, energy values are repulsive or negligibly small. Thus the high stability of parabanic acid crystals (m.p. 516 K with decomposition) cannot be explained.