A follow-up study of 100 patients with acute brucellosis for its prognosis and prevention

Objective

To prevent chronic brucellosis, this study analysed the changes in patient antibody titers, and the trajectories of biochemical indicators at different stages of brucellosis, identified relevant biomarkers, and explored risk factors affecting the prognosis of brucellosis patients.

Methods

A prospective cohort study was conducted to follow 100 patients with acute brucellosis. Laboratory serological test results [taken with a serum (tube) agglutination test (SAT)] and biochemical parameters (liver function, renal function, and hematological system) were measured repeatedly at four-time points: 0 weeks-baseline survey, 6 weeks after the first treatment, 12 weeks after the second treatment, and 3 months after the third treatment. The changes in the antibody titres and biochemical parameters at each time point were analysed for trend changes.

Results

One hundred patients with acute brucellosis were enrolled in this follow-up study, with 100% retention in follow-up. By the third follow-up, 21 patients had turned subacute and 11 had turned chronic. One-way repeated measures analysis of variance results showed statistically significant differences (p < 0.01) across the time points for the following five indicators: alanine aminotransferase, aspartate aminotransferase, total bilirubin, serum creatinine (SCr) and platelet count. The clinical symptoms of patients in the acute stage were mainly joint pain, fatigue, and fever, while those in the chronic stage complained primarily of joint pain and fatigue. The results of multivariate logistic analysis showed that joint pain [odds ratio (OR) = 3.652, 95% confidence interval (CI) =1.379-9.672], monoarticular pain (OR = 6.356, 95% CI = 4.660-8.669), elevated SCr (OR = 15.804, 95% CI = 1.644-151.966) and elevated haemoglobin (Hb) (OR = 1.219, 95% CI = 1.065-1.736) were risk factors for poor prognosis (not cured or chronic) in patients with brucellosis.

Conclusion

The trajectory of changes in patient SAT posirates and antibody titers can be used to distinguish patients with chronic brucellosis. The brucellosis is preventable and treatable, and the standard treatment can be effective in reducing the clinical symptoms of affected patients. If patients are not treated in a timely manner, joint pain, monoarticular pain, and elevated SCr are risk factors for patients who are not cured. Therefore, the treatment cycle for these patients should be extended.

[The value of preservation of subvalvular structures in patients with mitral and aortic valve replacement surgery and its effect on left ventricular contractility]

Objective: To discuss the clinical value of preserving subvalvular structure in mitral and aortic valve replacement surgery and its effect on left ventricular contractility. Methods: A total of 97 patients who underwent mitral valve replacement surgery in the Adult Cardiac Surgery of Heart Center of Henan Provincial People's Hospital, Central China Fuwai Hospital from June 2016 to December 2018 were selected as the research subjects, of whom 45 cases were preserved subvalvular structure and 52 cases were in the total resection group (intraoperative total resection of the mitral valve and subvalvular chordae tendineae). General cardiac function indexes and left ventricular function quantitative indexes were compared before and in 3 months and 6 months after the operation of the two groups; The changes of the overall longitudinal strain of the long axis of the apex and the overall circumferential strain of the short axis of the left ventricle determined by the two-dimensional speckle tracking technology were compared before and after the operation. Results: The ages of the patients in the preservation group and the total resection group were (41.8±11.3) and (43.3±10.6) years old, respectively, and the male proportions were 58.0% (26 cases) and 44.0% (23 cases), respectively, with no significant difference (all P>0.05). The aortic occlusion time and cardiopulmonary bypass time of the patients in the preservation group were (57.8±4.5) and (78.6±6.7) min, respectively, which were longer than those in the total resection group [(48.1±4.4) and (48.1±4.4) min, respectively] (all P<0.05). The left atrial pressure of the patients in the preservation group at shutdown was (8.4±1.8) mmHg (1 mmHg=0.133 kPa), which was lower than that of the total resection group (11.3±2.5) mmHg (P<0.001). There were interaction effects between groups and time in regards to the left ventricular end-diastolic diameter ( LVEDD ), left ventricular ejection fraction ( LVEF ) and Tei index, as well as the strain rate of mitral annulus and left ventricular wall of interventricular septum of the preservation group and the total resection group (all P<0.05). LVEDD and LVEF of patients in the preservation group at 3rd month after operation were (44.7±4.0) mm and (45.5±4.2) mm, and at 6th months were (56.5±4.9)% and (58.8±5.0)%, respectively, all larger than (42.7±3.6) mm and (42.7±3.6) mm, (54.5±4.6)% and (56.3±4.8)% of the total resection group. The measured value of LVESD in the preservation group at 3rd month after surgery was (32.6±3.2) mm, which was greater than that in the total resection group (31.2±3.4) mm (P<0.05). The Tei index of patients in the preservation group at 3rd and 6th months after surgery were 1.0±0.2 and 0.8±0.2, respectively, which were lower than those in the total resection group 1.2±0.3 and 0.9±0.2 (all P<0.05). Conclusion: Preserving the subvalvular structure during mitral valve replacement surgery can better improve the patient's left ventricular function and left ventricular systolic capacity.

[Role and mechanism of miRNA-181a in nonalcoholic fatty liver disease]

Objective: To investigate the role and probable mechanism of miRNA-181a in nonalcoholic fatty liver disease. Methods: HepG2 cells were treated with palmitic acid to construct a nonalcoholic fatty liver disease cell model, and the expression of miR-181a and lipidosis in the cells were measured. Transforming growth factor-β (TGF-β) was used to examine the effect of miR-181a expression in HepG2 cells. The miR-181a, lipidosis, reduced glutathione and reactive oxygen species (ROS) were determined by controlling and regulating the miR-183 expression levels after transfection with miR-181 mimics and inhibitors in HepG2 cells. The miR-181a target genes were predicted by bioinformatics analysis, and verified by real-time fluorescent quantitative PCR and western blotting. The independent sample t-test was used for the comparison between the two independent samples, and the comparison between multiple groups were accorded with the normal distribution, homogeneity of variance, and one-way analysis of variance. Results: Lipidosis was significantly increased after palmitic acid treatment in HepG2 cells, and the expression level of miR-181a was significantly increased than control group. After HepG2 cells were transfected with miR-181a inhibitors, the expression of miR-181a, triglycerides and reactive oxygen species were down-regulated, and reduced glutathione, predicting the mRNA and protein expression of target gene silencing information regulator 2 related enzyme 1 were up-regulated. However, the results were contrary to the above changes after transfection with miR-181a mimics. Conclusion: miR-181a participates in lipidosis and promotes lipid peroxidation in nonalcoholic fatty liver disease. miR-181a may affect the pathogenesis and progression of nonalcoholic fatty liver disease by inhibiting the expression of silencing information regulator 2 related enzyme 1.

[Retrospective analysis of curative effect of total pelvic organ resection and anal preservation in 20 patients with recurrence of cervical cancer after radical radiotherapy]

Objective: To explore the surgical method and effect of en bloc pelvic resection and anal preservation after radical radiotherapy for cervical cancer. Methods: Clinical data of 20 cervical cancer patients with central recurrence after radical radiotherapy underwent en bloc pelvic resection in the Tumor Hospital of Zhengzhou University and Hainan Provincial People's Hospital from January 2013 to December 2017 were retrospectively analyzed. The operative time, intraoperative blood loss, length of stay, postoperative anal function and postoperative complications were evaluated. Results: The median operation time of 20 patients with anal preservation after en bloc pelvic resection was 135.2 min, the median intraoperative blood loss was 680 ml, and the median hospitalization time was 16.5 days. Among them, 18 patients had good postoperative healing, and the anal function gradually returned to normal within 6 months after surgery, defecated 1~2 times per day.One patient showed incomplete adhesion between the external colon and the anus. One patient presented with pre-sacral infection. Postoperative pathology confirmed the recurrences in 20 patients, of which 11 cases were squamous cell carcinoma, 7 cases were adenocarcinoma, 2 cases were adenosquamous cell carcinoma. Conclusions: It is safe and reliable to preserve anus after en bloc pelvic resection for cervical cancer patients with radical radiotherapy. The anus function is good enough to improve the postoperative life quality of patients significantly.

Unique genetic profiles from cerebrospinal fluid cell-free DNA in leptomeningeal metastases of EGFR-mutant non-small-cell lung cancer: a new medium of liquid biopsy

Background

Leptomeningeal metastases (LM) are more frequent in non-small-cell lung cancer (NSCLC) with epidermal growth factor receptor (EGFR) mutations. Due to limited access to leptomeningeal lesions, the purpose of this study was to explore the potential role of cerebrospinal fluid (CSF) as a source of liquid biopsy in patients with LM.

Patients and methods

Primary tumor, CSF, and plasma in NSCLC with LM were tested by next-generation sequencing. In total, 45 patients with suspected LM underwent lumbar puncture, and those with EGFR mutations diagnosed with LM were enrolled.

Results

A total of 28 patients were enrolled in this cohort; CSF and plasma were available in 26 patients, respectively. Driver genes were detected in 100% (26/26), 84.6% (22/26), and 73.1% (19/26) of samples comprising CSF cell-free DNA (cfDNA), CSF precipitates, and plasma, respectively; 92.3% (24/26) of patients had much higher allele fractions in CSF cfDNA than the other two media. Unique genetic profiles were captured in CSF cfDNA compared with those in plasma and primary tissue. Multiple copy number variations (CNVs) were mainly identified in CSF cfDNA, and MET copy number gain identified in 47.8% (11/23) of patients was the most frequent one, while other CNVs included ERBB2, KRAS, ALK, and MYC. Moreover, loss of heterozygosity (LOH) of TP53 was identified in 73.1% (19/26) CSF cfDNA, which was much higher than that in plasma (2/26, 7.7%; P < 0.001). There was a trend towards a higher frequency of concomitant resistance mutations in patients with TP53 LOH than those without (70.6% versus 33.3%; P = 0.162). EGFR T790M was identified in CSF cfDNA of 30.4% (7/23) of patients who experienced TKI progression.

Conclusion

CSF cfDNA could reveal the unique genetic profiles of LM and should be considered as the most representative liquid biopsy medium for LM in EGFR-mutant NSCLC.

Radio frequency measurement and tuning of a 13 MeV Alvarez-type drift tube linac for a compact pulsed hadron source

This paper describes the radio frequency (RF) measurement and tuning result of a 13 MeV Alvarez-type drift tube linac (DTL) for a compact pulsed hadron source (CPHS) at Tsinghua University. The design, machining, assembly, and alignment of the DTL are presented for integrity. The CPHS project consists of a high-current proton linac (13 MeV, 16 kW, peak current of 50 mA, 0.5 ms pulse width at 50 Hz), a neutron target station, a small-angle neutron scattering instrument, and a neutron imaging/radiology station. The linac contains an electron cyclotron resonance ion source, a low energy beam transport line, a four-vane radio frequency quadrupole (RFQ) accelerator, an Alvarez-type DTL, a high energy beam transport line, and a RF power supply and distributor. Construction on the CPHS started in June 2009, and the CPHS has provided 2000 h since 2013 to users with the neutrons produced by the 3 MeV proton beam from the radio frequency quadrupole bombarding on the beryllium target as an achievement of its mid-term objective. Presently, the tuning of the assembled DTL cavity has been completed successfully. The 4.3-m-long DTL consists of 40 accelerating cells, among which 39 full-length drift tubes (DTs) are suspended inside the cavity, and two half-length DTs are mounted inside the two end flanges of the cavity. Each DT contains a permanent magnet quadrupole. Thirteen post couplers and nine tuners are available for the tuning of the field. The relative error of the field after tuning is within ±1.6%, with a tilt sensitivity within ±33%/MHz in all cells. The beam energy will reach its designed value of 13 MeV after the DTL is installed in the beam line downstream the 3 MeV RFQ accelerator.

[Research advances of relationship between non-alcoholic fatty liver disease and biliary tract diseases]

Recent studies have found that non-alcoholic fatty liver disease(NAFLD) has great impact on the development of biliary tract diseases. Here in this review, we summarized the relationship between NAFLD and the occurrence and development, risk factors and severity of cholestasis, gallstones, intrahepatic cholangiocarcinoma, primary biliary cirrhosis and bile microbiota, so as to further illuminate the pathogenesis of NAFLD and biliary tract diseases, obtain better diagnostic and therapeutic outcomes on NAFLD and biliary tract diseases.

[Individualized treatment of bilateral carotid body tumor]

Objective: To investigate individualized therapeutic strategy for bilateral carotid body tumors. Methods: Clinical data of 16 patients with bilateral carotid body tumor treated from January 2003 to August 2016 were retrospectively studied. Of the 16 patients, 9 were males and 7 were females; 5 were sporadic and 11 were familial; 8 cases were observed, 1 cases was malignant and treated with chemotherapy, and 7 cases were treated with surgery. The treatment course, perioperative complications and clinical efficacy were assessed. Comprehensive evaluation of bilateral carotid body tumors was performed based on the size of bilateral tumor, clinical manifestations, genetic tests and other indicators. Individual treatment strategies included observation, surgery and observation, bilateral surgery, radiotherapy or chemotherapy. Surgical resection of carotid body tumor was unilateral in 3 cases and bilateral in 3 cases; removal of bilateral carotid body tumors plus unilateral jugular bulb in 1 case; and the internal carotid artery was reconstructed with autologous greater saphenous vein in 1 case. Results: All patients were followed up for 3 months to 12 years. There was no patient death during perioperative period. Superior laryngeal nerve injury occurred in 2 case. Baroreceptor failure syndrome occurred in one patient, but it gradually recoverd with medical treatments. Conlusion: It is important to identify whether bilateral carotid body tumors are hereditary and to make an individualized therapeutic strategy for each patient with bilateral carotid body tumors, focusing on the improvement in the quality of life of patient.

A phase III randomised controlled trial of erlotinib vs gefitinib in advanced non-small cell lung cancer with EGFR mutations

Background:

A phase III trial was conducted to compare the safety and efficacy of erlotinib with that of gefitinib in advanced non-small cell lung cancer harbouring epidermal growth factor receptor mutations in exon 19 or 21.

Methods:

Eligible patients were randomised to receive erlotinib (150 mg per day) or gefitinib (250 mg per day) orally until disease progression or unacceptable toxicity. We aimed to determine whether erlotinib is superior to gefitinib in efficacy. The primary end point was progression-free survival.

Results:

A total of 256 patients were randomised to receive erlotinib (N=128) or gefitinib (N=128). Median progression-free survival was not better with erlotinib than with gefitinib (13.0 vs 10.4 months, 95% confidence interval (CI) 0.62–1.05, P=0.108). The corresponding response rates and median overall survival were 56.3% vs 52.3% (P=0.530) and 22.9 vs 20.1 months (95% CI 0.63–1.13, P=0.250), respectively. There were no significant differences in grade 3/4 toxicities between the two arms (P=0.172).

Conclusions:

The primary end point was not met. Erlotinib was not significantly superior to gefitinib in terms of efficacy in advanced non-small cell lung cancer with epidermal growth factor receptor mutations in exon 19 or 21, and the two treatments had similar toxicities.

[Clinical significance of the preoperative neutrophil lymphocyte ratio in the evaluation of the prognosis of laryngeal carcinoma]

OBJECTIVE

To explore the effect of preoperative neutrophil lymphocyte ratio (NLR) on the prognosis of patients with laryngeal carcinoma.

METHODS

Clinical data of 202 patients with laryngeal carcinoma treated from January 2004 to October 2009 were retrospective analyzed to determine the optimal critical value of NLR. To study whether NLR is an independent factor affecting the recurrence and 5-year survival rate of patients with laryngeal cancer after surgery, single factor and multivariate analyses were performed. The factors included age, gender, T stage, pathological differentiation, lymph node metastasis, primary tumor site and NLR value. The relationship between NLR and cervical lymph node metastasis was analyzed.

RESULTS

The optimal critical value of NLR was 2.85, by which cases were divided into high NLR group (NLR≥2.85) and low NLR group (NLR<2.85). Single factor and multivariate analyses indicated that T staging, lymph node metastasis, primary tumor location, and NLR were the independent factors affecting the recurrence of laryngeal carcinoma. T stage and lymph node metastasis were the independent factors affecting 5-year survival rate of laryngeal carcinoma. The increase of NLR value increased the rate of cervical lymph node metastasis.

CONCLUSION

Preoperative NLR level influences the recurrence and cervical lymph node metastasis of laryngeal carcinoma and can be considered a prognosis factor of laryngeal cancer.

Double-loop locking cross-stitch suture and suspension fixation for medial collateral ligament origin reconstruction

The purpose of this study was to summarize the clinical application and results of the double-loop locking cross-stitch suture and suspension fixation method for medial collateral ligament origin reconstruction. Thirty-six patients (21 males, 15 females) with an average age of 40 years (range = 17-58 years), who underwent treatment for acute fracture of the medial collateral ligament at our hospital from February 2008 to May 2009, were included in this study. All patients presented unilateral injuries (17 right-sided, 19 left-sided) and underwent repair with the double-loop locking cross-stitch suture and suspension fixation method. All incisions in this group of patients healed by first intention. Thirty-two patients were followed up for 6-20 months (average = 12 months). There were no reports of wound infection, ligament re-fracture or other complications in the follow-up period. Based on the Lysholm knee-scoring scale, the patients received a 100% excellent and good rating (20 patients - excellent score, 12 patients - good score) postoperatively. The advantages of the double-loop locking cross-stitch suture and suspension fixation method are a smaller incision, reliable fixation, and early restoration of knee joint stability. It is, therefore, an effective and low-risk method for the reconstruction of medial collateral ligament origin.

Effect of surgery treatment on hypersplenism caused by cirrhotic portal hypertension

AIM

Aim of the study was to summarize the types and quantities of peripheral hematocytopenia in the patients of hypersplenism caused by cirrhotic portal hypertension and investigate the effect of surgery, including splenectomy on the patient's peripheral blood cells and liver function.

METHODS

The quantities of peripheral blood cells in the 322 patients of hypersplenism, caused by cirrhotic portal hypertension, were retrospectively studied. Then, the preoperative and postoperative values of peripheral blood cells and liver function were compared in 266 patients who were followed up. The liver function was scored and graded according to Child-Pugh scoring system.

RESULTS

The study enrolled 322 patients who showed hematocytopenia, including multi-hemocyte decrease in 206 patients (64%) and simple hemocyte decrease in 116 patients (36%). After surgical treatment in the 226 patients who were followed up, the quantities of peripheral blood cells significantly increased (P<0.01), Child-Pugh grade A increased by 32 patients (14.2%), while Child-Pugh grade C increased only by 2 patients (0.9%), the liver function scores decreased (P<0.05).

CONCLUSION

Hypersplenism caused by cirrhotic portal hypertension mainly manifests as a multi-hemocyte decrease and rarely shows single types of hematocytopenia. Surgical intervention including splenectomy can increase the reduction of hemocytes and promote the recovery of liver function.

Analysis of 120 pediatric patients with nonmalignant disorders transplanted using unrelated plasma-depleted or -reduced cord blood

BACKGROUND

Unrelated cord blood (CB) is an important stem cell source for unrelated hematopoietic cell transplantation (HCT) of patients with nonmalignant disorders. Processing methods to prepare red blood cell-reduced CB units incur significant nucleated cell loss. In contrast, plasma depletion or reduction (PDR) processing of CB units entails the removal of only a portion of the plasma with minimal nucleated cell loss. However, there are relatively limited data regarding outcomes of CB transplants using units processed by PDR.

STUDY DESIGN AND METHODS

A Center for International Blood and Marrow Transplant Research (CIBMTR)-audited analysis was performed on 120 pediatric patients with nonmalignant disorders transplanted between November 2001 and January 2008 at 29 US and 17 international centers using PDR CB units from two CB banks.

RESULTS

Transplant characteristics were as follows: median age, 3.5 years (range, 0.1-14 years); median patient weight, 15 kg (range, 4-61 kg); 58% male; HLA matches (intermediate-resolution HLA-A and HLA-B and high-resolution HLA-DRB1) of the units used in these patients six of six in 26, five of six in 48, four of six in 47, and three of six or two of six in 6; median prefreeze total nucleated cell dose, 10.5×10(7)/kg; median prefreeze CD34+ dose, 3.7×10(5)/kg; and nonmyeloablative regimen in 24%. The median times to myeloid and platelet engraftment were 21 and 49 days, respectively. The cumulative incidence of reported Grade II to IV acute graft-versus-host disease (aGVHD) was 38±5%, and 19±4% had Grade III to IV aGVHD. The Kaplan-Meier estimates of 3-year transplant-related mortality, overall survival, and disease-free survival were 20±4, 79±4, and 70±6%, respectively.

CONCLUSION

These data demonstrate the effectiveness of PDR CB units for HCT.

A non-natural dinucleotide containing an isomeric L-related deoxynucleoside: dinucleotide inhibitors of anti-HIV integrase activity

The first X-ray crystal structure of a non-natural dinucleotide, 5'-O-phosphoryl-1'-deoxy-2'-isoadenylyl-(3' --> 5')-cytidine 6.5-hydrate (pIsodApC), C19H26N8O13P2 x 6.5H2O, belonging to a family of dinucleotides that contain an isomeric nucleoside component, is described. A complex system of hydrogen bonds between water molecules and various sites on the dinucleotide was found. All H atoms were located from electron-density difference maps, which allowed identification of protonation sites. Compounds of this family have been found to bind at the active site of HIV integrase and to be inhibitors of this key viral enzyme. These dinucleotides are completely resistant to cleavage by exonucleases; an abnormal dihedral angle twist in an internucleotide phosphate bond revealed in the X-ray crystal structure may be contributing to this unusual stability towards nucleases.

Crystals of ligand-free bovine neurophysin II

A modified neurophysin, des 1-6 bovine neurophysin II, has been crystallized in the absence of bound hormone or hormone analogue. These crystals represent the first crystals of ligand-free neurophysin, and are essential for understanding neurophysin-hormone recognition as well as hormone-induced neurophysin dimerization. The crystals diffract to beyond 1.8 A resolution, belong to space group P3(1)21 (or P3(2)21) with a = 48.86, c = 78.61 A, and contain one molecule per asymmetric unit.

Research on solid-state fermentation on rice chaff with a microbial consortium

A microbial consortium of Trichoderma reesei AS3.3711, Aspergillus niger 3.316 and Saccharomyces cerevisiaes AS2.399 was constructed to decomposed rice chaff on the basis of the characters of each microorganism and the mechanism of cellulases. In this experiment, rice chaff was pretreated before fermentation with NaOH so that the lignin structure of rice chaff was degraded and hemicellulose was dissolved partly, which remove the protection of lignin and hemicellulose on cellulose and demolish its special crystal structure. After pretreatment, rice chaff can be degraded more easily with the microbial consortium. The optimal technical paths and technological methods were achieved for intenerating rice chaff with the microbial consortium perfectly through orthogonal experiment. According to the technological methods, some experiments were done at 30 degrees C with pH 4.5. It was found that the highest filter paper enzyme activity (FPA) was 5.64 U/g and the ratio of cellulose degradation (RCD) was 28.05%.

[Genescan analysis of the loss of heterozygosity on the long arm of chromosome 6 in non-small cell lung cancer]

To investigate if there are microsatellite loci in the long arm of chromosome 6 that have close relationship with non-small cell lung cancer, Multiple PCR approach was used to analyze the 36 loci in the long arm of chromosome 6. The PCR products were analyzed in PAGE and then the electrophoresis maps were analyzed with Genescan and Genotyper. There is different LOH frequency in different loci. The total frequency of LOH in 41 lung cancers was 78%(32/41), with the highest frequency of LOH was detected on the locus D6S302(75%). There are 14 loci which have LOH frequency more than 20% and the loci are mainly located in 2 regions: 6q16.3-q21 [6 loci D6S458 (21.43%), D6S1694 (26.92%), D6S1717 (35.71%), D6S1565 (40%), D6S302 (75%), D6S1706 (36.36%) and 6q26-q27 (5 loci D6S1550 (38.46%), D6S264 (20%), D6S1585 (25%), D6S446 (33.33%), D6S281 (30.77%)], There may be tumor suppressor genes located in the two regions, which have a close relationship with non-small cell lung cancer.

The crystal structures of Phascolopsis gouldii wild type and L98Y methemerythrins: structural and functional alterations of the O2 binding pocket

Reported are the X-ray crystal structures of recombinant Phascolopsis gouldii methemerythrin (1.8-A resolution) and the structure of an O2-binding-pocket mutant, L98Y methemerythrin (2.1-A resolution). The L98Y hemerythrin (Hr) has a greatly enhanced O2 affinity, a slower O2 dissociation rate, a larger solvent deuterium isotope effect on this rate, and a greater resistance to autoxidation relative to the wild-type protein. The crystal structures show that the hydrophobic binding pocket of Hr can accommodate substitution of a leucyl by a tyrosyl side chain with relatively minor structural rearrangements. UV/vis and resonance Raman spectra show that in solution L98Y methemerythrin contains a mixture of two diiron site structures differing by the absence or presence of an Fe(III)-coordinated phenolate. However, in the crystal, only one L98Y diiron site structure is seen, in which the Y98 hydroxyl is not a ligand, but instead forms a hydrogen bond to a terminal hydroxo/aqua ligand to the nearest iron. Based on this crystal structure, we propose that in the oxy form of L98Y hemerythrin the non-polar nature of the binding pocket favors localization of the Y98 hydroxyl near the O2 binding site, where it can donate a hydrogen bond to the hydroperoxo ligand. The stabilizing Y98OH-O2H-interaction would account for all of the altered O2 binding properties of L98Y Hr listed above.

Preparation and X-ray crystallographic analysis of recombinant obelin crystals diffracting to beyond 1.1 A

Crystals of recombinant obelin, the Ca(2+)-regulated photoprotein from the marine hydroid Obelia longissima, have been grown from a solution containing PEG 8000 and potassium phosphate. Hexaminecobalt trichloride was used as an additive to increase the chance of crystallization. The crystals grow in a light yellow cubic form (0.5 x 0.5 x 0.45 mm) which diffracts to beyond 1.1 A resolution. The crystals belong to the space group C2, with unit-cell parameters a = 83.43, b = 54.92, c = 52.99 A, beta = 112.00 degrees. The asymmetric unit contains one molecule. Crystals exposed to calcium ion before and after X-ray irradiation emit light, confirming that the crystals consist of an active photoprotein.

Regulation of growth-regulated oncogene alpha expression by estrogen in human endothelial cells

AIM

To study the effect of estrogen on expression of growth-regulated oncogene alpha (GROalpha) in human umbilical vein endothelial cells (HUVEC) in vitro.

METHODS

Expressions of CXC chemokine GROalpha mRNA and protein were measured by Northern blotting assay and ELISA, respectively. The physiological significance of GROalpha expression was tested by static cell adhesion assay.

RESULTS

Both the GROalpha mRNA and protein levels decreased markedly after HUVEC were exposured to 17beta-estradiol (2 0.05 micromol/L. Moreover, the inhibition of the protein was depended on the concentration of 17beta-estradiol. Tamoxifen (0.1 micromol/L), an estrogen receptor alpha antagonist, alone did not affect GROalpha protein expression, but can reverse the E2 -induced inhibition of GROalpha protein expression (by up to 50 %) and the binding of U937 cells to E2-treated HUVEC (by up to 40 %).

CONCLUSION

Estrogen might functionally down-regulates GROalpha expression through estrogen receptor alpha on endothelial cells.

Structural basis for the substrate specificity of the feruloyl esterase domain of the cellulosomal xylanase Z from Clostridium thermocellum

Feruloyl esterases function in the cleavage of ferulic acid's bonds to arabinoxylan and pectin where the ferulic acid moieties cross-link the layers of polysaccharide chains within hemicellulose. This work presents the crystal structure of FAE_XynZ, the domain of Clostridium thermocellum's cellulosomal xylanase Z that displays feruloyl esterase activity. The structure was obtained via multiple isomorphous replacement with anomalous scattering (MIRAS) using three heavy atom derivatives and refined against X-ray diffraction data of up to 1.75 A resolution. The R-value of the final model was 0.187 (R(free) = 0.21). FAE_XynZ displays an eight-stranded alpha/beta-fold with the characteristic "catalytic triad" at the heart of the active site. To define the substrate specificity determinants of the enzyme, the crystal structures of FAE_XynZ and the inactive FAE_XynZ(S172A) mutant were determined in complexes with the feruloyl-arabinoxylans FAXX and FAX(3), respectively. In the complex crystals, the ferulic acid moieties are clearly recognizable and allowed identification of the hydrophobic binding pocket. The carbohydrate part of both substrates is not visible in either structure. The location of the putative carbohydrate binding-pocket was inferred based on the location and orientation of the adjacent ferulic acid molecule. Five of the six residues lining the pocket were found to be conserved in FAE A from Orpinomyces sp., which further supports the proposed role of these amino acids.

Structural basis for the emission of violet bioluminescence from a W92F obelin mutant

Mutation of the Trp92 that is known to lie within the active site of the photoprotein obelin from Obelia longissima, results in a shift of the bioluminescence color from blue (lambda(max)=485 nm) to violet. The corrected spectrum shows a new band with lambda(max)=410 nm now contributing equally to the one at longer wavelength. The crystal structure of this W92F obelin determined at 1.72 A resolution shows that there is no significant change in the dimensions of the active site between WT obelin (recombinant Ca2+-regulated photoprotein from Obelia longissima) and the mutant. It is proposed that the bioluminescence spectral shift results from removal of a hydrogen bond from the indole of W92 nearby a hydroxyl belonging to the 6-phenyl substituent of the substrate coelenterazine. Propagation of this change through a conjugated bond system in the excited state of the product coelenteramide affects the coupling of the N1-position and the hydrogen-bonded Y138.

Crystal structure of the transcription factor sc-mtTFB offers insights into mitochondrial transcription

Although it is commonly accepted that binding of mitochondrial transcription factor sc-mtTFB to the mitochondrial RNA polymerase is required for specific transcription initiation in Saccharomyces cerevisiae, its precise role has remained undefined. In the present work, the crystal structure of sc-mtTFB has been determined to 2.6 A resolution. The protein consists of two domains, an N-terminal alpha/beta-domain and a smaller domain made up of four alpha-helices. Contrary to previous predictions, sc-mtTFB does not resemble Escherichia coli sigma-factors but rather is structurally homologous to rRNA methyltransferase ErmC'. This suggests that sc-mtTFB functions as an RNA-binding protein, an observation standing in contradiction to the existing model, which proposed a direct interaction of sc-mtTFB with the mitochondrial DNA promoter. Based on the structure, we propose that the promoter specificity region is located on the mitochondrial RNA polymerase and that binding of sc-mtTFB indirectly mediates interaction of the core enzyme with the promoter site.