Achieving eco-innovative smart glass design with the integration of opinion mining, QFD and TRIZ

Modern consumption patterns lead to massive waste, which poses challenges in storage and highlights the urgent need for more sustainable product development. Customer feedback on products plays a crucial role in product design, yet previous studies overlooked these invaluable insights. In response, this study introduces a novel systematic methodology that integrates the strengths of text mining, Quality Function Deployment (QFD), and the Theory of Inventive Problem Solving (TRIZ). Text mining techniques are utilized to extract customer requirements from online platforms, while QFD is used to translate these requirements into technical specifications. By integrating the contradiction matrix from TRIZ theory with the triptych, technical conflicts are resolved. The design process for next-generation smart glasses is employed as an illustrative case to validate the proposed integrated innovation design approach. Analytical outcomes suggest that the introduced methodology can effectively address sustainable product design challenges and sets the stage for future advancements in smart glasses.

[Clinicopathological characteristics and immune microenvironment of breast squamous cell carcinoma]

Objective: To investigate the clinicopathological characteristics of breast squamous cell carcinoma and to analyze the relationship between its immune microenvironment tumor infiltrating lymphocytes (TILs) and prognosis. Methods: Forty-four cases of primary squamous cell carcinoma of the breast diagnosed and treated in the First Affiliated Hospital of Air Force Medical University, Xi'an, China from January 2006 to July 2022 were selected. Their clinicopathological characteristics were analyzed. The cell composition of TILs was evaluated using immunohistochemistry (Mainly markers of B lymphocytes, T lymphocytes and plasma cells). The relationship between TILs and prognosis was also analyzed. Results: The 44 patients of breast squamous cell carcinoma were all female and all were invasive carcinoma. Eight cases (8/44, 18.2%) were squamous cell carcinoma, while 36 cases (36/44, 81.8%) were mixed squamous cell carcinoma. The mixed components included non-specific carcinoma and spindle cell metaplastic carcinoma (17 cases each). One case contained ductal carcinoma in situ of the breast and 1 case contained tubular carcinoma. The proportion of squamous cell carcinoma was 10% to 90%. The cases with pure squamous cell carcinoma often had a large cystic cavity, which was lined by atypical squamous epithelium, while infiltrating squamous cell carcinoma nests were seen in the breast tissue around the cystic cavity. Immunohistochemical staining showed that p63 and CK5/6 were expressed in the squamous cell carcinoma component, but ER, PR and HER2 were not, except for one case of HER2 1+. The positive rates of TRPS1 and PDL-1 were 76% and less than 1%, respectively. Fifteen cases were in the high TILs group (TILs≥30%) and 29 cases were in the low TILs group (TILs<30%). Twenty-three patients were followed up for 5 to 118 months. Among them, 12 died within 3 years and 9 were alive at the end of the follow up. There was no significant difference in TNM stage, TILs and prognosis between simple squamous cell carcinoma and mixed squamous cell carcinoma. Conclusions: Breast squamous cell carcinoma can be divided into simple squamous cell carcinoma and mixed squamous cell carcinoma. There are differences in gross findings and histology between the simple and mixed squamous cell carcinoma of the breast. Sufficient samples should be taken to avoid missing the diagnosis of a minor squamous component. The prognosis of patients with high TILs is significantly better than that of patients with low TILs. The expression rate of TRPS1 in primary squamous cell carcinoma of breast is high and helpful to the differential diagnosis from metastatic squamous cell carcinoma.

The effect of photolysis of sodium citrate treated with gold chloride using coloured light on the generation of gold nanoparticles and the repression of WiDr colon cancer cells

Gold nanoparticles (GNPs) are usually formed via a wet chemical method using gold (III) chloride trihydrate (GC), which is treated with stable reducing agents such as sodium citrate (SC). This study determines the effect of coloured light on the formation of GNPs by irradiation of SC after the addition of GC (SCGC) and the effect of the SCGC photolytic procedure on the suppression of WiDr colon cancer cells by forming reactive oxygen species. The absorbance of surface plasmon resonance peaks at 523 nm are 0.069 and 0.219 for SCGC when treated with blue light illumination (BLI) and violet light irradiation (VLI), respectively, whereas green and red light treatments have little or no effect. Most GNPs have diameters ranging from 3 to 15 nm, with a mean of 6 nm, when SCGC is exposed to VLI for 1.5 h. Anionic superoxide radicals (O2•-) are formed in a charge-transfer process after SCGC under VLI treatment; however, BLI treatment produces no significant reaction. Moreover, SCGC under VLI treatment proves to be considerably more effective at inhibiting WiDr cells than BLI treatment, as firstly reported in this study. The reduction rates for WiDr cells treated with SCGC under BLI and VLI at an intensity of 2.0 mW/cm2 for 1.5 h (energy dose, 10.8 J/cm2) are 4.1% and 57.7%, respectively. The suppression rates for WiDr cells treated with SCGC are inhibited in an irradiance-dependent manner, the inhibition percentages being 57.7%, 63.3%, and 80.2% achieved at VLI intensities of 2.0, 4.0, and 6.0 mW/cm2 for 1.5 h, respectively. Propidium iodide is a fluorescent dye that detects DNA changes after cell death. The number of propidium iodide-positive nuclei significantly increases in WiDr cells treated with SCGC under VLI, suggesting that SCGC photolysis under VLI is a potential treatment option for the photodynamic therapy process.

[Clinicopathological and molecular genetic characteristics of ELOC mutated renal cell carcinoma]

Objective: To investigate the clinicopathological features, molecular genetic features, differential diagnosis and prognosis of ELOC mutated renal cell carcinoma. Methods: From January 2015 to June 2022, 11 cases of renal cell carcinoma with clear-cell morphology, expression of CAⅨ and CK7 and no 3p deletion were collected. Two cases of ELOC mutant renal cell carcinoma were diagnosed using whole exome sequencing (WES). The clinical features, morphology, immunophenotype, FISH and WES results were analyzed. The relevant literature was reviewed. Results: The two patients were both male, aged 29 and 51 years, respectively. They were both found to have a renal mass by physical examination. The maximum diameters of the tumors were 3.5 cm and 2.0 cm, respectively. At the low magnification, the tumors were well-defined. The tumor cells showed a pushing border and were separated by thick fibrous bands, forming nodules. The tumor cells were arranged in a variety of patterns, including tubular, papillary, solid nest or alveolar. At high magnification, the tumor cells were large, with well-defined cell borders and clear cytoplasm or fine eosinophilic granules. CAⅨ was diffusely box-like positive in both cases. Case 1 was partially and moderately positive for CK7, strongly positive for CD10, diffusely and moderately positive for P504S, and weakly positive for 34βE12. In case 2, CK7 and CD10 were both partially, moderately positive and P504s were diffusely positive, but 34βE12 was negative. FISH results showed that both cases had no 3p deletion. ELOC c.235T>A (p.Y79N) mutation was identified using WES in case 1, while ELOC c.236_237inv (p.Y79C) mutation was identified in case 2. Conclusions: As a new clinical entity, ELOC mutated renal cell carcinoma may be underdiagnosed due to its overlap with clear cell renal cell carcinoma in morphology and immunophenotype. The diagnosis of renal cell carcinoma with ELOC mutation should be confirmed by morphology, immunohistochemistry, FISH and gene mutation detection. However, more additional cases are needed to explain its biological behavior and prognosis.

An investigation of the influence of reactive oxygen species produced from riboflavin-5'-phosphate by blue or violet light on the inhibition of WiDr colon cancer cells

Riboflavin-5'-phosphate (FMN), an innocuous product of riboflavin (RF) phosphorylation, is vital for humans. FMN is sensitive to light illumination, as indicated by reactive oxygen species (ROS) formation. This investigation was undertaken to evaluate the influence of blue light illumination (BLI) and violet light illumination (VLI) upon FMN to develop a method to inhibit WiDr colon cancer cells by FMN photolysis. When FMN is subjected to BLI and VLI, it inhibits WiDr colon cancer cells by generating superoxide radical anions (O2•-). The respective reduction rates are 42.6 and 81.9 % in WiDr colon cancer cells for FMN treated with BLI and VLI at 20 W/m2 for 0.5 h. FMN treated with VLI inhibits WiDr colon cancer cells more effectively than BLI. Propidium iodide (PI) is a fluorescent dye that is used to detect abnormal DNA due to cell death by apoptosis or necrosis. The PI-positive count for nuclei increased significantly for the WiDr colon cancer cells that were treated with FMN under VLI at 20 W/m2 for 0.5 h. FMN photolysis achieved using VLI allows efficient photodynamic therapy (PDT) by triggering the cytotoxicity of FMN on WiDr colon cancer cells.

Photochemical reductive deamination of alpha-amino aryl alkyl ketones

Photochemical reductive deamination of alpha-amino aryl alkyl ketones under photosensitizer-free conditions is presented. This protocol features high efficiency and selectivity. A plausible reaction pathway is proposed based on ultraviolet-visible absorption investigation, control experiments and deuterium-labelling studies. Mechanistic study reveals that the alpha-hydrogen atom of the ketone product originated from water.

[Distribution characteristics of plasma renin concentration in patients with aldosterone-producing adenoma]

Objective: To analyze the distribution characteristics of plasma renin concentration (PRC) in patients with aldosterone-producing adenoma (APA) and its impact on diagnosis. Methods: In this retrospective case series, clinical data from 200 patients with APA (80 men and 120 women; mean age 45.6 years) in the First Affiliated Hospital of Chongqing Medical University from November 2013 to January 2022 were evaluated. PRC was determined by automated chemiluminescence immunoassay. The distribution characteristics of PRC were analyzed, and 8.2 mU/L was used as the low renin cutoff to evaluate whether renin was suppressed. Results: The median PRC was 1.6 mU/L (range, 0.4-41.5 mU/L). There were 116 patients with APA with PRC of ≤2 mU/L, 41 patients with 2<PRC≤4 mU/L. PRC was not suppressed (PRC>8.2 mU/L) in 8.0% (16/200) of the patients with APA. And PRC was not suppressed in 2.5% (5/200) of the patients with APA, resulting in a primary aldosteronism negative screening outcome. Conclusions: Although most patients with APA have low PRC, there are a small number (8%) of patients whose PRC has not been fully suppressed, which can lead to missed diagnoses during primary aldosteronism screening. While primary aldosteronism is highly suspected, further investigations are required to determine the diagnosis, even if PRC is not fully suppressed at screening.

[Analysis of efficacy and factors influencing sequential combination therapy with tenofovir alafenamide fumarate after treatment with entecavir in chronic hepatitis B patients with low-level viremia]

Objective: To observe the efficacy and factors influencing sequential or combined tenofovir alafenamide fumarate (TAF) after treatment with entecavir (ETV) in patients with chronic hepatitis B (CHB) with low-level viremia (LLV). Methods: 126 CHB cases treated with ETV antiviral therapy in the Department of Infectious Diseases of the First Affiliated Hospital of Nanchang University from January 2020-September 2022 were retrospectively collected. Patients were divided into a complete virologic response (CVR) group (n = 84) and a low-level viremia (LLV) group (n = 42) according to the HBV DNA level during treatment. Clinical characteristics and laboratory indicators of the two groups at baseline and 48 weeks were analyzed by univariate analysis. Patients in the LLV group were divided into three groups according to their continued antiviral treatment regimen until 96 weeks: continued use of ETV as a control group; replacement of TAF as a sequential group; and combination of ETV and TAF as a combined group. The data of the three groups of patients were analyzed by one-way analysis of variance for 48 weeks. HBV DNA negative conversion rate, HBeAg negative conversion rate, alanine aminotransferase (ALT), creatinine (Cr), and liver stiffness test (LSM) were compared among the three groups after 96 weeks of antiviral treatment. Multivariate logistic regression was used to analyze the independent factors influencing the occurrence of HBV DNA non-negative conversion in LLV patients at 96 weeks. Receiver operating characteristic curve (ROC) was used to evaluate the effectiveness of predicting the occurrence of HBV DNA non-negative conversion in LLV patients at 96 weeks. Kaplan-Meier was used to analyze the cumulative negative rate of DNA in LLV patients, and the Log-Rank test was used for comparison. HBV DNA and HBV DNA negative conversion rates during treatment were observed dynamically. Results: Univariate analysis showed statistically significant differences in age, BMI, HBeAg positivity rate, HBV DNA, HBsAg, ALT, AST, and LSM at baseline between the CVR group and the LLV group (P < 0.05). Univariate analysis of variance revealed no statistically significant difference among the three groups of LLV patients at 48 weeks (P > 0.05). HBV-DNA negative conversion rate in the sequential group and the combination group was significantly higher than that in the control group after 96 weeks of treatment (88.89% vs. 41.18%, 85.71% vs. 41.18%, χ (2) = 10.404, P = 0.006). HBeAg negative conversion rate was higher than that of the control group, with no statistically significant difference (P > 0.05).Compared with the control group, ALT, Cr, and LSM in the sequential group and the combined group were equally improved to varying degrees, with a statistically significant difference (P < 0.05). Subsequent use of ETV and HBV DNA at 48 weeks were independent risk factors for HBV DNA positivity at 96 weeks in LLV patients (P < 0.05). The AUC of HBV DNA at 48 weeks was 0.735 (95%CI: 0.578 ~ 0.891), the cut-off value was 2.63 log(10) IU/ml, and the sensitivity and specificity were 76.90% and 72.40%, respectively. DNA conversion rate was significantly lower in LLV patients receiving 48-week ETV and 48-week HBV DNA≥2.63 log10 IU/mL than in patients receiving sequential or combined TAF and 48-week HBV DNA < 2.63 log(10) IU/mL. HBV DNA negative conversion rates in the sequential group and combined group at 72 weeks, 84 weeks, and 96 weeks were higher than those in the control group during the period from 48 weeks to 96 weeks of continuous treatment, and the differences were statistically significant (P < 0.05). Conclusion: Sequential or combined TAF antiviral therapy could more effectively improve the 96-week CVR rate, as well as hepatic and renal function, and alleviate the degree of hepatic fibrosis in CHB patients with LLV following ETV treatment. Subsequent use of ETV and HBV DNA load at 48 weeks were independent predictors of HBV DNA positivity at 96 weeks in LLV patients.

[Applications of the NDR and DIAL models for risk prediction on cardiovascular disease in patients with type 2 diabetes in Ningbo]

Objective: To validate the performance of cardiovascular risk prediction models based on the Sweden National Diabetes Register (NDR) and Diabetes Lifetime-perspective prediction (DIAL) model for assessing risks of 5-year and 10-year cardiovascular disease (CVD) among Chinese patients with type 2 diabetes. Methods: Based on the Chinese Electronic Health Records Research in Yinzhou study, 83 503 patients with type 2 diabetes aged 30-75 years without a history of CVD at baseline were included from January 1, 2010 to December 31, 2020. Recalibrated NDR model was used to estimate 5-year risk, while the recalibrated DIAL model was used to predict 5-year and 10-year risks. The competing events adjusted Kaplan-Meier analysis was used to obtain the observed cardiovascular events. Discrimination C statistics evaluated model accuracy, calibration χ² value, and calibration plots. Results: Through a median follow-up of 7.0 years, 7 326 cardiovascular events, and 2 937 non-vascular deaths were identified among a total of 83 503 subjects. The recalibrated NDR model overestimated 5-year risk by 39.4% in men and 8.6% in women, whereas the overestimation for the recalibrated DIAL model was 14.6% in men and 50.1% in women. The DIAL model had a better discriminative ability (C-statistic=0.681, 95%CI: 0.672-0.690) than NDR model (C-statistic=0.667, 95%CI: 0.657-0.677) in 5-year risk prediction for men, and the models had a similar ability for women (C-statistic=0.699, 95%CI: 0.690-0.708 for NDR and C-statistic=0.698, 95%CI: 0.689-0.706 for DIAL). The prediction accuracy of the DIAL model was improved in the 10-year risk, with the underestimation being 1.6% for men and the overestimation being 12.8% for women. Conclusions: Both recalibrated NDR and DIAL models overestimated 5-year cardiovascular risk in Chinese patients with type 2 diabetes, while the higher overestimation was shown using the DIAL model. However, the improvement was found in predicting 10-year CVD risk using the DIAL model, which suggested the value of lifetime risk prediction and indicated the need for research on the lifetime risk prediction model for cardiovascular risk assessment in Chinese patients with type 2 diabetes.

A study of the effect of reactive oxygen species induced by violet and blue light from oxytetracycline on the deactivation of Escherichia coli

Oxytetracycline (OTC), a tetracycline antibiotic, is a broad-spectrum antibacterial agent. In this investigation, liquid chromatography-mass spectrometry (LC-MS) is utilized to determine the effects of blue light (λ = 448 nm) illumination (BLIA) and violet light (λ = 403 nm) illumination (VLIA) on conformational changes in OTC at pH 7.8. The photochemical effect of OTC that is exposed to BLIA and VLIA on the deactivation of Escherichia coli (E. coli) is studied. The deactivation of E. coli has an insignificant effect on treatment with OTC alone. OTC is relatively unstable under BLIA and VLIA illumination in an alkaline solution, and OTC has been shown to inactivate E. coli by generating reactive oxygen species (ROS). Less anionic superoxide radicals (O₂^•-) are generated from OTC that is treated with BLIA than that from VLIA treatment, so OTC is more efficient in inactivating E. coli under VLIA. Inactivation of reduction rates of 0.51 and 3.65 logs in E. coli are achieved using 0.1 mM OTC under BLIA for 120 min and VLIA for 30 min, respectively, under the same illumination intensity (20 W/m²). Two photolytic products of OTC (PPOs) are produced when OTC is exposed to BLIA and VLIA, with molecular ions at m/z 447 and 431, molecular formulae C₂₁H₂₂N₂O₉ and C₂₁H₂₂N₂O₈, and masses of 446.44 and 430.44 g/mol, respectively. The results show that when exposed to VLIA, OTC exhibits enhanced inactivation of E. coli, suggesting that the photochemical treatment of OTC is a potential supplement in a hygienic process.

[The method of determination for butyronitrile and isobutyronitrile in the air of workplace by dissolved desorption-gas chromatography]

Objective: To establish a method for the determination of butyronitrile and isobutyronitrile in the air of workplace by gas chromatography. Methods: In March 2020, butyronitrile and isobutyronitrile in the air of workplace was collected by silica gel, eluted with methanol, separated and determined by gas chromatogram with flame ionization detector, the characteristics of determination of nitrile and isobutyronitrile by gas chromatography were analyzed. Results: The limit of detection for butyronitrile and isobutyronitrile was 0.33 μg/ml. The linear range of butyronitrile determined by this method was 1.60-1600.00 μg/ml, y=2.295x-3.480, and the coefficient correlation was 0.99998, and the minimum detection concentration was 0.22 mg/m(3) (collected sample volume was 1.50 L) . The within-run precisions were 2.43%-4.12%, the between-run precisions were 1.72%-3.70%, and the desorption rates were 93.26%-98.41%. The linear range of isobutyronitrile determined by this method was 1.52-1520.00 μg/ml, y=2.208x-0.102, and the coefficient correlation was 0.99998, and the minimum detection concentration was 0.22 mg/m(3) (collected sample volume was 1.50 L) . The within-run precisions were 2.52%-3.22%, the between-run precisions were 1.20%-3.82%, and the desorption rates were 96.85%-102.50%. The sealed samples could be stored at least 10 days at room temperature without significant loss. Conclusion: The method has the advantages of good precision, high sensitivity and simple operation. It is suitable for the simultaneous determination of butyronitrile and isobutyronitrile in the air of workplace.

Effects of free radicals from doxycycline hyclate and minocycline hydrochloride under blue light irradiation on the deactivation of Staphylococcus aureus, including a methicillin-resistant strain

Doxycycline hyclate (DCH) and minocycline hydrochloride (MH) are tetracycline antibiotics and broad-spectrum antimicrobial agents. The changes in DCH and MH under blue light (λ = 462 nm) irradiation in alkaline conditions (BLIA) were investigated. Deactivation caused by superoxide anion radical (O₂^•-) and deactivation from DCH and MH during photolysis on Staphylococcus aureus (S. aureus), including methicillin-resistant S. aureus (MRSA), were studied. DCH is relatively unstable compared to MH under BLIA. The level of O₂^•- generated from the MH-treated photoreaction is lower than that from DCH photolysis, and the DCH-treated photoreaction is more efficient at inactivating S. aureus and MRSA at the same radiant intensity. DCH subjected to BLIA decreased the viability of S. aureus and MRSA by 3.84 and 5.15 log, respectively. Two photolytic products of DCH (PPDs) were generated under BLIA. The mass spectra of the PPDs featured molecular ions at m/z 460.8 and 458.8. The molecular formulas of the PPDs were C₂₁H₂₂N₂O₁₀ and C₂₂H₂₄N₂O₉, and their exact masses were 462.44 and 460.44 g/mol, respectively. These results bolster the photolytic oxidation that leads to DCH-enhanced deactivation of S. aureus and MRSA. Photochemical treatment of DCH could be applied as a supplement in hygienic processes.

[Value of dynamic MRI in monitoring the microenvironmental changes of anti-vascular therapy in a xenograft model]

Objective: To explore the feasibility of dynamic-enhanced magnetic resonance imaging (DCE-MRI) and blood oxygen level-dependent MRI (BOLD-MRI) in assessing the hemodynamics and tumor aggressiveness during treatment. Methods: The colon cancer xenograft model was established in BALB/C nude mice with HCT116 cell line. Sixteen nude mice were randomly divided into treatment and control groups (aged 6 to 8 weeks, weighted 15 to 18 g, Certificate No. 11400700325797), which were treated with bevacizumab and saline by intraperitoneal injection on the 1st, 4th, 7th, 10th and 13th day. DCE-MRI and BOLD-MRI were performed before and on the 3th, 6th, 9th, 12th, and 15th day after treatment. The vascular maturity and microenvironment hypoxia were confirmed by pathology. Results: The tumor volume of treatment group was significantly smaller than that of control group after 15 days ((712±43) vs (1 051±112) mm(3),P<0.01).The measurements of K(trans) were (0.135±0.005),(0.147±0.006),(0.175±0.009),(0.161±0.006), (0.140±0.005),(0.116±0.008)/min (F=81.386, P<0.01); K(ep) were (0.788±0.030),(0.804±0.036),(0.983±0.059), (1.105±0.091),(0.840±0.047),(0.786±0.041)/min(F=45.901,P<0.01);Ve were (0.652±0.006), (0.559±0.026), (0.466±0.016), (0.286±0.027), (0.363±0.020), (0.246±0.033) (F=384.290, P<0.01) and R2* values were (24.813±0.961), (24.675±1.070), (21.425±1.371), (17.850±0.885), (24.613±0.640), (27.013±0.734)/s (F=89.323, P<0.01) showed different trends with time in the treatment group, and the differences were statistically significant. The K(trans) values and tumor vessel maturity index (VMI) were higher than baseline values during 3-12 d after treatment. CD31 positive staining rate and VMI had the strongest correlations with K(trans) values (r=0.854 and 0.795), followed by AUC(180) (r=0.750 and 0.808), Ve (r=0.744 and 0.712) and K(ep) values (r=0.729 and 0.758), all P<0.05. R2* value positively correlated with the positive staining rate of HIF-1α and fibronectin (r=0.810 and 0.816), all P<0.05. Conclusion: DCE-MRI and BOLD-MRI are adequate to observe the tumor perfusion and hypoxia during anti-vascular treatment, and the R2* value can predict the tumor metastatic potential during the process of vascular normalization.

[A study on the features and influences of first physiology translation Ti Yong Shizhang]

In 1884, Kong Qinggao translated Huxley's Lessons in Elementary Physiology into a Chinese version, namely Ti Yong Shizhang. The book, with John Kerr Proofreading, turns out to be the first modern physiologic textbookin Chinese. Even so, this translation has long been ignored by researchers in the history of physiology and with no systematical introduction.The Chinese version was basically true to the western original featuring comprehensive knowledge and profound theories, with only a few pieces of content deleted and minimal order adjusted. The printing of 85 illustrations was as much refined as the original ones. The newly coined physiological terms in Chinese version had a certain impact at the time. As the first physiologic textbook to cultivate the earliest modern physicians, its copies were spread in the intellectual community. Conclusively, Ti Yong Shizhang played a significant role in the spread of Western physiology in China.

[Clinical short-term and long-term efficacy of endoscopic submucosal dissection in the treatment of early low rectal cancer and precancerous lesions]

Objective: To evaluate the short-term and long-term efficacy of endoscopic submucosal dissection (ESD) in the treatment of early low rectal cancer and precancerous lesions. Methods: Inclusion criteria: (1) Distance from the lower margin of tumor to the anal was ≤ 5 cm. (2) Early low rectal cancers were any size rectal epithelial tumors with infiltration depth limited to the mucosa and submucosa, which were diagnosed by postoperative pathology as high-grade intraepithelial neoplasia or adenocarcinoma of the rectum with infiltration depth of intramucosal or submucosal cancer (M or SM stage). (3) Precancerous lesions included adenoma and low-grade intraepithelial neoplasia of the rectum. (4) Patients received ESD treatment. Patients with tumor invasion depth over submucosa by pathology were excluded. From January 2008 to January 2018, 63 patients meeting the above criteria in Peking University First Hospital were enrolled in this descriptive cohort study. The disease characteristics, clinical manifestations, pathological types, treatment time, hospitalization time, en bloc resection rate (resection of the whole lesion), complete resection rate (both the horizontal and vertical incision margins were negative), postoperative complications and follow-up results were analyzed. Cummulative survival rate was calculated by Kaplan-Meier. Results: The diameter of the lesion was (29.0±23.4) mm and the distance from the lesion to the anus was (2.7±1.8) cm. The median operation time was 45.0 (range, 10.0 to 360.0) minutes, the median hospitalization time was 3.0 (range, 2.0 to 12.0) days, en bloc resection rate was 100%, complete resection rate was 96.8% (61/63), and 1 case (1.6%) had postoperative bleeding. The follow-up rate was 87.3% (55/63) and the median follow-up time was 57.9 (range, 15.6 to 121.1) months. No local recurrence was found during the follow-up period and the 5-year survival rate was 100%. Conclusion: Short- and long-term efficacy of ESD are quite good in the treatment of patients with early low rectal cancer and precancerous lesions.

Effects of Epigallocatechin Gallate on the Stability of Epicatechin in a Photolytic Process

Catechins belonging to polyhydroxylated polyphenols are the primary compounds found in green tea. They are associated with many physiological properties. Epicatechin (EC) is a non-gallate-type catechin with four phenolic hydroxyl groups attached. The changes in EC treated with color light illumination in an alkaline condition were investigated by chromatographic and mass analyses in this study. In particular, the superoxide anion radical (O₂•^-) was investigated during the EC photolytic process. EC is unstable under blue light illumination in an alkaline solution. When EC was treated with blue light illumination in an alkaline solution, O₂•^- was found to occur via a photosensitive redox reaction. In addition, the generation of monomeric, dimeric, and trimeric compounds is investigated. On the other hand, epigallocatechin gallate (EGCG), which is a gallate-type catechin, is stable under blue light illumination in an alkaline solution. Adding EGCG, during the blue light illumination treatment of EC decreased photolytic formation, suggesting that gallate-type catechins can suppress the photosensitive oxidation of EC. Gallate-type catechins are formed via the esterification of non-gallate-type catechins and gallic acid (GA). The carbonyl group on the gallate moiety of gallate-type catechins appears to exhibit its effect on the stability against the photosensitive oxidation caused by blue light illumination.

Effects of Blue-Light-Induced Free Radical Formation from Catechin Hydrate on the Inactivation of Acinetobacter baumannii, Including a Carbapenem-Resistant Strain

Catechin is a flavan-3-ol, a derivative of flavans, with four phenolic hydroxyl groups, which exhibits a wide range of physiological properties. Chromatographic analyses were employed to examine the effects of blue light irradiation on the changes of catechin hydrate in an alkaline condition. In particular, the detection of a superoxide anion radical (O₂•⁻), a reactive oxygen species (ROS), and the inactivation of Acinetobacter baumannii (A. baumannii)—including a carbapenem-resistant A. baumannii (CRAB)—was investigated during the photoreaction of catechin hydrate. Following basification with blue light irradiation, the transparent solution of catechin hydrate turned yellowish, and a chromogenic catechin dimer was separated and identified as a proanthocyanidin. Adding ascorbic acid during the photolytic treatment of catechin hydrate decreased the dimer formation, suggesting that ascorbic acid can suppress the photosensitive oxidation of catechin. When catechin hydrate was irradiated by blue light in an alkaline solution, O₂•⁻ was produced via photosensitized oxidation, enhancing the inactivation of A. baumannii and CRAB. The present findings on the photon-induced oxidation of catechin hydrate provides a safe practice for the inactivation of environmental microorganisms.

Effects of blue or violet light on the inactivation of Staphylococcus aureus by riboflavin-5'-phosphate photolysis

The light sensitive compound riboflavin-5'-phosphate (or flavin mononucleotide, FMN) generates reactive oxygen species (ROS) upon photo-irradiation. FMN is required by all flavoproteins because it is a cofactor of biological blue-light receptors. The photochemical effects of FMN after irradiation by blue or violet light on the inactivation of Staphylococcus aureus strains, including a methicillin-resistant strain (MRSA), were investigated in this study. Upon blue- or violet-light photo-treatment, FMN was shown to inactivate S. aureus due to the generated ROS. Effective bacterial inactivation can be achieved by FMN photolysis without an exogenous electron provider. Inactivation rates of 94.9 and 95.2% in S. aureus and MRSA, respectively, can be reached by blue light irradiation (2.0mW/cm²) with 120μM FMN for 120min. A lower FMN concentration and a shorter time are required to reach similar effects by violet light irradiation. Inactivation rates of 96.3 and 97.0% in S. aureus and MRSA, respectively, can be reached by violet light irradiation (1.0mW/cm²) with 30μM FMN for 30min. The sensitivity of the inherent photosensitizers is lower under blue-light irradiation. A long exposure photolytic treatment of FMN by blue light is required to inactivate S. aureus. Violet light was found to be more efficient in S. aureus inactivation at the same radiant intensity. FMN photolysis with blue or violet light irradiation enhanced the inactivation rates of S. aureus and MRSA. FMN photochemical treatment could be a supplemental technique in hygienic decontamination processes.

[Influence of subthalamic nucleus deep brain stimulation on cognition and acetylcholine in a rat model of Parkinson's disease]

Objective: To illustrate the effect of subthalamic nucleus deep brain stimulation (STN-DBS)on cognitionand its underlying mechanisms in a rat model of Parkinson's disease (PD). Methods: Thirty healthy male Sprague-Dawley rats were randomly divided into 3 groups: control group (healthy rats, n=10), model group (PD rats, n=10), and stimulation group (PD rats receiving high frequency stimulation, n=10). The cognitive functionof rats was tested through Morris water maze and acetylcholine levels in cortex, hippocampus and striatum have been examined through ELISA. Results: During Morris water mazetest, spatial learning and memory of PD ratsdeteriorated compared with healthy ones, withlonger escape latency[on day 4, (38±14) s vs (20±4) s, P=0.047; on day 5, (32±13) s vs (16±8) s, P=0.032]and shorter time in the platform region[(10±6) s vs (19±5) s, P=0.023], which could be restored by STN-DBS. Similar results demonstrated that the expression of Ach in hippocampus[(1 473±233) s vs (1 950±344) s, P=0.039]and striatum[(1 661±271) s vs (2 240±290) s, P=0.007]was significantly lower in PD rats than those in healthy rats, and STN-DBS treatment reversed this decline to insignificant. Conclusion: The rat model of PD suffer from a decline in cognition, and STN-DBS contributes to cognitive recovery, possibly due to regulating Ach levels in cognition-associated regions of the brain, includinghippocampus and striatum.

Photo-catalytic polymerization of catechin molecules in alkaline aqueous

Polyphenols are associated with a wide range of physiological properties. Catechin is a flavan-3-ol with five phenolic hydroxyl groups. After blue light illumination, the transparent solution of catechin became yellowish. The effects of visible light illumination (400-800nm) were investigated on molecular structures and antioxidant capacities of catechin. Under the neutral or alkaline aqueous with the illumination of blue light, the photolysis and polymerization of catechin were observed in this study. A chromogenic catechin dimer was separated and identified as a proanthocyanidin by the chromatographic technique and mass spectrometry. For quantitative evaluation, the signal intensities of the catechin and the photochemical product show a negative correlation in the liquid chromatograms. The oligomer of flavan-3-ols (catechin dimer) is suggested as a dimeric B type proanthocyanidin, which has the molecular formula C₃₀H₂₆O₁₂ and 578.14g/mol in exact mass. The mass spectrum of catechin dimer had characteristic ion signals in m/z 577, 560, 439Da. However, the total phenolic contents and scavenging O₂^- activity of catechin treated by blue light illumination are not changed significantly at the neutral or alkaline aqueous. Our results of photocatalytic oligomers of catechin provide a novel way to explain the sensory changes of green tea and a biochemical mechanism under the irradiation environments.

Investigations of riboflavin photolysis via coloured light in the nitro blue tetrazolium assay for superoxide dismutase activity

Determination of the superoxide dismutase activity is an important issue in the fields of biochemistry and the medical sciences. In the riboflavin/nitro blue tetrazolium (B2/NBT) method, the light sources used for generating superoxide anion radicals from light-excited riboflavin are normally fluorescent lamps. However, the conditions of B2/NBT experiments vary. This study investigated the effect of the light source on the light-excitation of riboflavin. The effectiveness of the photolysis was controlled by the wavelength of the light source. The spectra of fluorescent lamps are composed of multiple colour lights, and the emission spectra of fluorescent lamps made by different manufacturers may vary. Blue light was determined to be the most efficient for the photochemical reaction of riboflavin in visible region. The quality of the blue light in fluorescent lamps is critical to the photo-decomposition of riboflavin. A blue light is better than a fluorescent lamp for the photo-decomposition of riboflavin. The performance of the B2/NBT method is thereby optimized.

Investigations of blue light-induced reactive oxygen species from flavin mononucleotide on inactivation of E. coli

The micronutrients in many cellular processes, riboflavin, flavin mononucleotide (FMN), and flavin adenine dinucleotide (FAD) are photo-sensitive to UV and visible light for generating reactive oxygen species (ROS). Produced from phosphorylation of riboflavin, FMN is more water-soluble and rapidly transformed into free riboflavin after ingestion. This study investigated the application of visible blue light with FMN to development of an effective antimicrobial treatment. The photosensitization of bacterial viability with FMN was investigated by light quality, intensity, time, and irradiation dosage. The blue light-induced photochemical reaction with FMN could inactivate Escherichiacoli by the generated ROS in damaging nucleic acids, which was validated. This novel photodynamic technique could be a safe practice for photo-induced inactivation of environmental microorganism to achieve hygienic requirements in food processing.

Novel nonsense and frameshift NTRK1 gene mutations in Chinese patients with congenital insensitivity to pain with anhidrosis

Congenital insensitivity to pain with anhidrosis (CIPA; MIM 256800) is a rare autosomal recessive disorder characterized by absence of reaction to noxious stimuli, recurrent episodes of fever, anhidrosis, and mental retardation. It is caused by mutations in the gene coding for neurotrophic tyrosine kinase receptor type 1 (NTRK1; MIM# 191315). We screened two Chinese CIPA cases for mutations in the NTRK1 gene and examined their phenotype. Two novel mutations of the NTRK1 gene and two known mutations were identified. Including our two novel mutations, there are now 62 different NTRK1 gene mutations reported in patients with CIPA. We find that a combination of two null alleles usually leads to the severe phenotype, while the mild form of the CIPA disease is associated with at least one mild allele. Thirty-four among the 62 mutations (55%) are located within the tyrosine kinase domain of the NTRK1 protein. We concluded that the tyrosine kinase domain is a hot spot for mutations.

Effect of thyroid hormone on the development and gene expression of hormone receptors in rat testes in vivo

Thyroid hormone is known to play a pivotal role in the regulation of prepuberal rat testes development and function with specific influence on the differentiation of Sertoli cells, the only cell type that expresses thyroid hormone receptors in testes. To explore in vivo effects of thyroid hormone on testes development and the regulation of testicular gene expression, the hyper- and hypothyroid rat models were established by T3 injection to pups (ip 100 microg/kg bw) and by oral administration of 6-N-propyl-2-thiouracil (PTU) to the lactating mother from days 1 to 21 post-delivery. Half of the rats from each group were sacrificed at 21 days of age, and the other half were allowed to recover with discontinued treatments from day 22 to day 50. At 21 days of age, a significantly elevated serum T3 level was observed in hyperthyroid rats (179.5 ng/dl) vs controls (97.5 ng/dl), and in hypothyroid rats a significantly lower level of T3 was detected (26.1 ng/dl). However, serum T4 concentration was significantly lower in both hyper- (0.105 microg/dl) and hypothyroid (0.058 microg/dl) rats compared to the controls (2.48 microg/dl). In recovered rats in which the serum T3 and T4 were restored to normal, the serum T levels remained remarkably lower in both hyper- and hypothyroid rats. The significantly decreased body and testes weights observed in both hyper- and hypothyroid rats at 21 days of age were not restored by the time they were 50 days old. Histological analyses of testes of 21-day-old hypothyroid rats revealed smaller-sized seminiferous tubules, incomplete lumen formation and delayed germ cell differentiation and in hyperthyroid rats an increased number of early stage spermatocytes was found. Testicular mRNA levels of follicle-stimulating hormone receptor (FSH-R), luteinizing hormone receptor (LH-R) and androgen binding protein (ABP) were studied by Northern blot hybridization. At 21 days of age data showed that FSH-R mRNA levels were significantly higher in both hyper- and hypothyroid rat testes compared to controls, but no differences were detected in recovered 50-day-old rats. Significantly decreased ABP mRNA levels were detected only in hypothyroid rat testes compared to those in both the hyperthyroid and control groups at 21 days of age, but no significant change was observed in recovered 50-day-old rats. To further evaluate the effect of thyroid hormone on the Leydig cell function, the 2.3/2.6 kb specific LH-R hybridization bands were detected with rat LH-R cRNA probe. Significant suppression of LH-R mRNA levels was only observed in the hypothyroid rat testes at 50 days of age. The testicular thyroid hormone receptors (TRs) and the regulation of TR by thyroid hormone were investigated using semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) assays. Both TRalpha and TRbeta mRNAs were identified in the testes from 21- and/or 50-day-old rats. TRalpha mRNA levels were significantly increased in hypothyroid rat testes and were suppressed in hyperthyroid rats at 21 days of age and no changes of TRalpha mRNA were found in recovered animals. Our in vivo data strongly suggest that the thyroid hormone directly affects the development of prepuberal testes and the regulation of FSH-R and ABP gene expression in Sertoli cells, as well as the LH-R mRNA levels in Leydig cells, which may lead to further modulating the effect of gonadotropins on testes function.

Pharmacokinetics of anastrozole in Chinese male volunteers

AIM

To compare pharmacokinetics of domestic and imported tablets of anastrozole.

METHODS

Twenty male Chinese volunteers were enrolled in a randomized crossover study with a single oral dose of 1 mg of the two formulations respectively. The anastrozole in plasma was measured by gas chromatography with electron-captured detector. Area under the drug concentration-time curve was evaluated by variance analysis and two one-side t-test.

RESULTS

A two-compartment model was adopted in anastrozole plasma concentration-time data analysis. The paramaters such as Cmax, Tmax, T1/2beta, and AUC(0-infinity) were (10 +/- 3) and (10.2 +/- 2.5) microg/L, (1.2 +/- 0.5) and (1.3 +/- 0.4) h, (42 +/- 14) and (41 +/- 26) h, (443 +/- 141) and (429 +/- 121) microg . h . L-1, respectively, and there were no significant differences between the two formulations.

CONCLUSION

Domestic and imported anastrozole were of bioequivalence. The relative bioavailability of the domestic tablet was 100 % +/- 9 %.

Multimerization potential of the cytoplasmic domain of the human immunodeficiency virus type 1 transmembrane glycoprotein gp41

We previously demonstrated that an envelope mutant of human immunodeficiency virus type 1 lacking the entire cytoplasmic domain interferes in trans with the production of infectious virus by inclusion of the mutant envelope into the wild-type envelope complex. We also showed that the envelope incorporation into virions is not affected when the wild-type envelope is coexpressed with the mutant envelope. These results suggest that an oligomeric structure of the cytoplasmic domain is functionally required for viral infectivity. To understand whether the cytoplasmic domain of human immunodeficiency virus type 1 transmembrane protein gp41 has the potential to self-assemble as an oligomer, in the present study we fused the coding sequence of the entire cytoplasmic domain at 3' to the Escherichia coli malE gene, which encodes a monomeric maltose-binding protein. The expressed fusion protein was examined by chemical cross-linking, sucrose gradient centrifugation, and gel filtration. The results showed that the cytoplasmic domain of gp41 assembles into a high-ordered structural complex. The intersubunit interaction of the cytoplasmic domain was also confirmed by a mammalian two-hybrid system that detects protein-protein interactions in eucaryotic cells. A cytoplasmic domain fragment expressed in eucaryotic cells was pulled down by glutathione-Sepharose 4B beads via its association with another cytoplasmic domain fragment fused to the C terminus of the glutathione S-transferase moiety. We also found that sequences encompassing the lentiviral lytic peptide-1 and lentiviral lytic peptide-2, which are located within residues 828-856 and 770-795, respectively, play a critical role in cytoplasmic domain self-assembly. Taken together, the results from the present study indicate that the cytoplasmic domain of gp41 by itself is sufficient to assemble into a multimeric structure. This finding supports the hypothesis that a multimeric form of the gp41 cytoplasmic domain plays a crucial role in virus infectivity.

Zinc induces mitochondria apoptogenesis in prostate cells

BACKGROUND AND PURPOSE

Prostate secretory epithelial cells have the unique function and capability of accumulating extremely high intracellular levels of zinc. One of the effects of this accumulation is inhibition of cell growth due, in part, to an increase in apoptosis. The present studies were conducted to determine if this zinc-induced apoptosis involves stimulation of mitochondrial apoptogenesis.

MATERIALS AND METHODS

The PC-3 a human malignant prostate cell line, which is zinc accumulating, was exposed to medium supplemented with physiologic levels of zinc.

RESULTS

By 24 h, zinc treatment resulted in the translocation of cytochrome c from the mitochondria to the cytosol, the activation of caspase-9 and caspase-3, and eventually, the cleavage of nuclear poly(ADP)-ribose polymerase (PARP). Under similar conditions, exposure of freshly prepared rat ventral prostate cells (which are also zinc accumulating) resulted in increased apoptosis following translocation of cyochrome c and activation of caspases-9 and 3. The human prostate PZ-HPV-7 cells, which do not accumulate zinc, did not exhibit any apoptotic effect from zinc treatment.

CONCLUSION

The accumulation of high intracellular levels of zinc by prostate cells induces mitochondrial apoptogenesis. This represents a newly identified physiological effect of zinc in the regulation of prostate cell growth.

Synthetic retinoid CD437 induces S-phase arrest and apoptosis in human prostate cancer cells LNCaP and PC-3

BACKGROUND

Exposure of prostate carcinoma cell lines to retinoids, which function through the classical retinoic acid nuclear receptor, (RARs) or retinoid X receptors (RXRs), results in minimal cytostatic inhibition of cell proliferation.

METHODS

Growth inhibition and various regulatory responses were investigated in two human prostate carcinoma cell lines (LNCaP and PC-3) treated with or without a synthetic retinoid, CD 437.

RESULTS

Incubation of prostate carcinoma cell lines with a novel retinoid CD437 resulted in the marked inhibition of proliferation. LNCaP and PC-3 possessed IC50 values for CD437 of 375 nM and 550 nM, respectively. Incubation with 1 microM CD437 for 24 hr resulted in 100% and 60% inhibition of growth in LNCaP and PC-3 cells, respectively. Simultaneously, cell flow cytometric analyses revealed a dramatic increase of the cell population in S phase, in both LNCaP (from 38.6% up to 86.7%) and PC-3 (27.9% to 55.7%), and a decreased proportion of cells in G2 phase, in LNCaP (from 23.7% down to 1.2%) and PC-3 (14.9% to 2.2%), indicating a significant S-phase arrest. The cell growth inhibition and S-phase arrest in these cells were followed by apoptosis, as revealed by the acquisition of the characteristic cell morphology including the appearance of apoptotic bodies, and further confirmed by cellular DNA fragmentation. CD437-induced-S phase arrest was associated with upregulated mRNA levels of p21waf1/cip1/sdi1 in both LNCaP (p53+/+) and PC-3 (53-/-) cells.

CONCLUSIONS

CD437 represents a unique retinoid that induces S-phase arrest and apoptosis in both androgen-dependent (LNCaP) and -independent (PC-3) human prostate cancer cells, suggesting a potential role of CD437 in the treatment of human prostate cancer.

A new 1,2-deoxytaxane diterpenoid from Taxus chinensis

The bark of Taxus chinensis yielded a new taxane diterpenoid, 2-deacetoxy-7,9-dideacetyltaxinine J ( 1) together with several known taxoids. (1)H- and (13)C-NMR data of 1 are reported.

Crystal structure of fructose-1,6-bisphosphatase complexed with fructose 2,6-bisphosphate, AMP, and Zn2+ at 2.0-A resolution: aspects of synergism between inhibitors

The crystal structure of fructose-1,6-bisphosphatase (Fru-1,6-Pase; EC 3.1.3.11) complexed with Zn2+ and two allosteric regulators, AMP and fructose 2,6-bisphosphate (Fru-2,6-P2) has been determined at 2.0-A resolution. In the refined model, the crystallographic R factor is 0.189 with rms deviations of 0.014 A and 2.8 degrees from ideal geometries for bond lengths and bond angles, respectively. A 15 degrees rotation is observed between the upper dimer C1C2 and the lower dimer C3C4 relative to the R-form structure (fructose 6-phosphate complex), consistent with that expected from a T-form structure. The major difference between the structure of the previously determined Fru-2,6-P2 complex (R form) and that of the current quaternary T-form complex lies in the active site domain. A zinc binding site distinct from the three binding sites established earlier was identified within each monomer. Helix H4 (residues 123-127) was found to be better defined than in previously studied ligated Fru-1,6-Pase structures. Interactions between monomers in the active site domain were found involving H4 residues from one monomer and residues Tyr-258 and Arg-243 from the adjacent monomer. Cooperativity between AMP and Fru-2,6-P2 in signal transmission probably involves the following features: an AMP site, the adjacent B3 strand (residues 113-118), the metal site, the immediate active site, the short helix H4 (residues 123-127), and Tyr-258 and Arg-243 from the adjacent monomer within the upper (or lower) dimer. The closest distance between the immediate active site and that on the adjacent monomer is only 5 A. Thus, the involvement of H4 in signal transmission adds another important pathway to the scheme of the allosteric mechanism of Fru-1,6-Pase.

Toward a mechanism for the allosteric transition of pig kidney fructose-1,6-bisphosphatase

We examine structural aspects of the allosteric transition of pig kidney fructose-1,6-bisphosphatase (Fru-1,6-Pase) by analyzing the X-ray structures of the R and T form enzymes. The results show a hierarchical structural change during the R to T transition. Upon binding of AMP, a cascade of structural changes occurs starting from the AMP site: expansion of the AMP site, local conformational changes of helices H1 and H2, independent rotations and translation of helices H1, H2 and H3 (and loops connecting them), reorganization of the AMP domain as a whole and its 1.9 degrees rotation relative to the fructose-1,6-bisphosphate domain, and conformational changes at the C1-C2 and C1-C4 interfaces leading to the quaternary conformational change of a 17 degrees rotation between dimers. The AMP inhibition results from the relative movement between the AMP and FBP domains which distorts the active site during the transition by shifting the metal binding sites to unfavourable positions. Communication that ensures cooperativity during R to T transition relies on changes in positions of helices H1, H2 and H3, loops 127-131, 168-170 and 187-192, and on N-terminal residues. All of these features are close to the C1-C4 and symmetry equivalent C2-C3 interfaces and the relatively small C1-C3 interface of the T form. These secondary structures form the framework along which structural changes due to AMP binding can propagate to other parts of the monomers as well as across monomer interfaces. Future dynamics studies may be useful to analyze initiation, propagation and completion of the quaternary conformational change of Fru-1,6-Pase upon AMP binding. Also, site directed mutagenesis experiments are expected to provide more detailed descriptions of the importance of each of the residues that has been identified here in the proposed mechanisms.

The allosteric site of human liver fructose-1,6-bisphosphatase. Analysis of six AMP site mutants based on the crystal structure

The molecular structure of human liver fructose-1,6-bisphosphatase complexed with AMP was determined by x-ray diffraction using molecular replacement, starting from the pig kidney enzyme AMP complex. Of the 34 amino acid residues which differ between these two sequences, only one interacts with AMP; Met30 in pig kidney is Leu30 in human liver. From this analysis, six sites in which side chains of amino acid residues are in contact with AMP, Ala24, Leu30, Thr31, Tyr113, Arg140, and Met177, were mutated by polymerase chain reaction. The wild-type and mutant forms were expressed in Escherichia coli, purified, and their kinetic properties determined. Circular dichroism spectra of the mutants were indistinguishable from that of the wild-type enzyme. Kinetic analyses revealed that all forms had similar turnover numbers, Km values for fructose 2,6-bisphosphate, and inhibition constants for fructose 2,6-bisphosphate. Apparent Ki values for AMP inhibition of the Leu30 --> Phe and Met177 --> Ala mutants were similar to those of the wild-type enzyme, but the apparent Ki values for the Arg140 --> Ala and Ala24 --> Phe mutants were 7-to 20-fold higher, respectively. The Thr31 --> Ser mutant exhibited a 5-fold increase in apparent Ki for AMP, while mutation of Thr31 to Ala increased the apparent Ki 120-fold. AMP inhibition of the Tyr113 --> Phe mutant was undetectable even at millimolar AMP concentrations. Fructose 2,6-bisphosphate potentiated AMP inhibition of the mutants to the same extent as for the wild-type enzyme, except in the case of the Thr31 --> Ala and Tyr113 --> Phe mutants. Thus, the Met177 --> Ala mutant suggests that the side chain beyond C alpha is not needed for AMP binding, and that the Leu30 --> Phe mutant preserves the AMP contacts with these side chains. Thr31, Tyr113, and Arg140 form key hydrogen bonds to AMP consistent with strong side chain interactions in the wild-type enzyme. Finally, the absence of any effect of fructose 2,6-bisphosphate on AMP inhibition observed in the Thr31 --> Ala mutant may be an important clue relating to the mechanism of synergism of these two inhibitors.

Allosteric transition of fructose-1,6-bisphosphatase

Structural changes during the R-to-T transition of fructose-1,6-bisphosphatase (EC 3.1.3.11) form a hierarchy, in which structural changes at one level are supported by those at the other levels. The quaternary conformational changes involve a 17 degrees rotation between the upper and lower dimers, and a 3.4 degrees rotation between monomers in a dimer. Within monomers, the FBP domain, which remains rigid during the R-to-T transition, rotates 2.3 degrees relative to the AMP domain, which undergoes significant structural reorientations. The most important of these reorientations are the newly identified partially ordered loop residues 55-61 in the T state and reorientations of helices H1, H2, and H3. Supporting these structural changes are numerous readjustments of hydrogen bonding and van der Waals interactions throughout the entire tetrameric protein. Propagation of structural changes during the R-to-T transition relies primarily on helices H1, H2, H3, and loop 50-72. The change that begins at the AMP site causes reorientation of H1, H2, and H3 and changes of interactions across the C1-C4 (C2-C3) interface. These changes may propagate down H1, H2, H3, and loop 50-72 to affect interactions across the C1-C2 (C3-C4) and C1-C3 (C2-C4) interfaces. AMP inhibition is most probably caused by reduced metal binding affinity due to structural changes of metal ligands (Glu97, Asp118, and Asp121) in the active site. The eight-stranded beta-sheet, particularly the beta-strand B3, which connects Lys112 and Tyr113 of the AMP site with Asp118 and Asp121 of the metal site, may be responsible for communication between the AMP and active sites. Additional structural changes that support such communication include reorientation of the FBP domain and H1, H2, and H3 relative to the eight-stranded beta-sheet, and new conformations of loop 54-72 in the T state as AMP binds.

Crystallographic studies of the catalytic mechanism of the neutral form of fructose-1,6-bisphosphatase

The crystal structures of fructose-1,6-bisphosphatase (EC 3.1.3.11) complexed with substrate alone or with substrate analogues in the presence of divalent metal ions have been determined. The substrate analogues, 2,5-anhydro-D-glucitol-1,6-bisphosphate (AhG-1,6-P2) and 2,5-anhydro-D-mannitol-1,6-bisphosphate (AhM-1,6-P2), differ from the alpha and beta anomers of fructose-1,6-bisphosphate (Fru-1,6-P2), respectively, in that the OH on C2 is replaced by a hydrogen atom. Structures have been refined at resolutions of 2.5 to 3.0 A to R factors of 0.172 to 0.195 with root-mean-square deviations of 0.012-0.018 A and 2.7-3.8 degrees from the ideal geometries of bond lengths and bond angles, respectively. In addition, the complex of substrate with the enzyme has been determined in the absence of metal. The electron density at 2.5-A resolution does not distinguish between alpha and beta anomers, which differ for the most part only in the position of the 1-phosphate group and the orientation of the C2-hydroxyl group. The positions of the 6-phosphate and the sugar ring of the substrate analogues are almost identical to those of the respective anomer of the substrate. In the presence of metal ions the positions of the 1-phosphate groups of both alpha and beta analogues differ significantly (0.8-1.0 A) from those of anomers of the substrate in the metal-free complex. Two metal ions (Mn2+ or Zn2+) are located at the enzyme active site of complexes of the alpha analogue AhG-1,6-P2. Metal site 1 is coordinated by the carboxylate groups of Glu-97, Asp-118, and Glu-280 and the 1-phosphate group of substrate analogue, while the metal site 2 is coordinated by the carboxylate groups of Glu-97, Asp-118, the 1-phosphate group of substrate analogue, and the carbonyl oxygen of Leu-120. Both metal sites have a distorted tetrahedral geometry. However, only one metal ion (Mg2+ or Mn2+) is found very near the metal site 1 in the enzyme's active site in complexes of the beta analogue AhM-1,6-P2 or for Mg2+ in the complex of the alpha analogue AhG-1,6-P2. This single metal ion is coordinated by the carboxylate groups of Glu-97, Asp-118, Asp-121, and Glu-280 and the 1-phosphate group of substrate analogue in a distorted square pyramidal geometry.(ABSTRACT TRUNCATED AT 400 WORDS)

Structural similarities between fructose-1,6-bisphosphatase and inositol monophosphatase

Fructose-1,6-bisphosphatase and inositol monophosphatase are found to share a similar secondary structure topology even though their sequences have very limited homology. Both enzymes have a layered alpha beta alpha beta alpha type structure and similar tertiary structures. All but one of the metal binding residues are conserved between these two enzymes and homologous proteins. The exception is Glu-280 in fructose-1,6-bisphosphatase to Asp-220 in inositol monophosphatase.

Crystal structure of the neutral form of fructose 1,6-bisphosphatase complexed with regulatory inhibitor fructose 2,6-bisphosphate at 2.6-A resolution

The three-dimensional structure of the complex between fructose 1,6-bisphosphatase (EC 3.1.3.11) and the physiological inhibitor beta-D-fructose 2,6-bisphosphate (Fru-2,6-P2), an analogue of the substrate (fructose 1,6-bisphosphate), has been refined at 2.6-A resolution to a residual error (R) factor of 0.171. The rms deviations are 0.012 A and 2.88 degrees from ideal geometries of bond lengths and angles, respectively. The Fru-2,6-P2 occupies the active sites of both polypeptides C1 and C2 in the crystallographic asymmetric unit in the space group P3(2)21. The furanose and 6-phosphate of Fru-2,6-P2 are located at the fructose 6-phosphate site established earlier, and the 2-phosphate binds to the OH of Ser-124, the NH3+ of Lys-274, and the backbone NH of Gly-122 and Ser-123. Backbone displacements of 1 A occur for residues from Asp-121 to Asn-125. Model building of substrate alpha-D-Fru-1,6-P2 based on the binding structure of Fru-2,6-P2 in the active site shows interactions of the 1-phosphate with the backbone NH of Ser-123 and Ser-124. In the AMP sites, density peaks attributed to Fru-2,6-P2 are seen in C1 (and C4) but not in C2 (and C3). This minor binding of Fru-2,6-P2 to AMP sites partially explains the synergistic interaction between AMP and Fru-2,6-P2 and the protection of the AMP site from acetylation in the presence of Fru-2,6-P2. In the synergistic interaction between AMP and Fru-2,6-P2, inhibition of catalytic metal binding by the presence of Fru-2,6-P2 at the active site, and propagation of structural changes over some 28 A along beta-strand B3 from residues 121 to 125 in the active site to Lys-112 and Tyr-113 in the AMP site, as well as movement of helices across the interdimeric interfaces, may affect AMP binding and the subsequent R-to-T transition. In addition, occupancy of Fru-2,6-P2 at the AMP sites of C1 and C4 may favor binding of AMP to the remaining unoccupied AMP sites and thus promote the accompanying quaternary conformational changes.

Conformational transition of fructose-1,6-bisphosphatase: structure comparison between the AMP complex (T form) and the fructose 6-phosphate complex (R form)

A structure of the neutral form of fructose-1,6-bisphosphatase complexed with AMP has been determined by the molecular replacement method and refined at a 2.5-A resolution to a crystallographic R factor of 0.169. The root-mean-square errors of the structure from standard geometry are 0.013 A for bond lengths and 2.99 degrees for bond angles. Comparison of the AMP complex with the F6P complex shows that dimer C3-C4 twists about 19 degrees about a molecular 2-fold axis when dimers C1-C2 of the R and T forms of the enzyme are superimposed one another and that a slight shift of about 1 A of the AMP domain partially compensates this twist. The R to T transition of the enzyme does not significantly change the conformation of the F6P-binding site. However, residues at the divalent metal site and the AMP site show significant positional shifts. If these results can be extended to substrate in place of F6P, they suggest that regulation of the enzyme by AMP may occur partly through effects on metal-ion affinity or position. AMP binds to the same sites of the T and R forms, but only half-occupancy was observed in the alkaline R form. Sequential binding of AMP, at least in pairs, is suggested as the unligated R form is converted to the T form. Two possible pathways are suggested for allosteric communication over about 28 A between the AMP site and the active site: one via helices H1, H2, and H3 and another via the eight-stranded beta-sheet.(ABSTRACT TRUNCATED AT 250 WORDS)

Crystal structure of the neutral form of fructose-1,6-bisphosphatase complexed with the product fructose 6-phosphate at 2.1-A resolution

The crystal structure of fructose-1,6-bisphosphatase (EC 3.1.3.11) complexed with the product fructose 6-phosphate (F6P) has been refined at 2.1-A resolution to an R factor of 0.177 with root-mean-square deviations of 0.014 A and 2.9 degrees from the ideal geometries of bond lengths and bond angles, respectively. The secondary structures but not the trace of the unligated enzyme have been slightly revised in the F6P complex at this higher resolution. Helix H4 in the unligated structure has been refined to a helix-like coil, and two very short 3(10) helices have been found, one in H4 and one in H5. F6P at 10 mM concentration in the absence of divalent metals in our study shows major binding at the active site and minor binding at the AMP site. The major site has almost equal full occupancy in the C1 and C2 chains of the crystallographic asymmetric unit, while the minor site shows occupancy only in the C1 chain at about 50%. The electron density in both (2Fo - Fc) and (Fo - Fc) maps calculated by omitting F6P slightly favors the beta anomer of D-F6P over the alpha anomer. Possible functions of the active-site residues are discussed, and candidates are suggested for site-directed mutagenesis.

Binding of substrate CO2 to the active site of human carbonic anhydrase II: a molecular dynamics study

Molecular dynamics has been used to study binding of substrate CO2 to the active site of human carbonic anhydrase II. Three potential CO2 binding sites have been located. The first is at the active-site hydrophobic pocket (the catalytically productive site), where CO2 is approximately 3.5 A from the zinc ion and interacts with His-94, His-119, Val-121, Val-143, Leu-198, Thr-199, the zinc ion, and the zinc-bound hydroxide ion. The second CO2 binding site is approximately 6 A from the zinc ion, where CO2 interacts with His-64, His-94, Leu-198, Thr-200, Pro-201, Pro-202, and some active-site water molecules. The third CO2 binding site is approximately 10 A from the zinc ion, is largely solvated by water molecules, and interacts with His-64, Asn-67, and Gln-92. At these three CO2 binding sites, the CO2 molecule is highly localized (the average Zn-CO2 distance fluctuation is approximately 1 A) and favors the linear binding orientation toward the zinc ion. This linear binding orientation of CO2 and its electrostatic interaction with the zinc ion direct diffusion of CO2 toward the zinc ion and facilitate the nucleophilic attack from O of the zinc-bound OH- to C of CO2 in the productive hydrophobic binding site. Finally, the two CO2 binding sites outside the hydrophobic binding pocket, which may represent two intermediate states along the CO2 binding pathway, could play important roles as a CO2 relay.

Hydration of CO2 by carbonic anhydrase: intramolecular proton transfer between Zn2+-bound H2O and histidine 64 in human carbonic anhydrase II

The energy barrier for the intramolecular proton transfer between zinc-bound water and His 64 in the active site of human carbonic anhydrase II (HCA II) has been studied at the partial retention of diatomic differential overlap (PRDDO) level. The most important stabilizing factor for the intramolecular proton transfer is the zinc ion, which lowers the pKa of zinc-bound water and electrostatically repels the proton. The energy barrier of 127.5 kcal/mol for proton transfer between a water dimer is completely removed in the presence of the zinc ion. The zinc ligands, which donate electrons to the zinc ion, raise the barrier slightly to 34 kcal/mol for a 4-coordinated zinc complex including three imidazole ligands from His 94, His 96, and His 119 and to 54 kcal/mol for the 5-coordinated zinc complex including the fifth water ligand. A few model calculations indicate that these energy barriers are expected to be reduced to within experimental range (approximately 10 kcal/mol) when large basis set, correlation energies, and molecular dynamics are considered. The proton-transfer group, which functions as proton receiver in the intramolecular proton transfer, helps to attract the proton; and the partially ordered active site water molecules are important for proton relay function.

Effects of [D-Arg6, Trp7, Leu8, Pro9NEt]-luteinizing hormone-releasing hormone (sGnRH-A) and [D-Ala6, Pro9NEt]-luteinizing hormone-releasing hormone (LHRH-A), in combination with pimozide or domperidone, on gonadotropin release and ovulation in the Chinese loach and common carp

The effects of LHRH-A and sGnRH-A alone and in combination with the dopamine receptor antagonists pimozide (PIM) and domperidone (DOM) on stimulation of gonadotropin (GtH) secretion and ovulation in Chinese loach (Paramisgurnus dabryanus) and common carp (Cyprinus carpio) were studied. When tested in the absence of a dopamine receptor antagonist, sGnRH-A was about 10-fold more potent than LHRH-A in stimulating GtH secretion in loach, whereas these peptides were of similar effectiveness in common carp. Both peptides were effective alone in inducing ovulation in loach, but were ineffective in common carp. PIM and DOM stimulate a small but significant increase in serum GtH, and greatly potentiate the effects of LHRH-A and sGnRH-A on GtH secretion and ovulation in both species. DOM was of equal or somewhat greater potency than PIM in potentiating the action of releasing hormone agonists in loach; however, DOM had markedly greater effectiveness in common carp. sGnRH-A in the presence of DOM was more effective than LHRH-A in stimulating GtH secretion and ovulation in common carp. The present studies suggest that there are marked differences in the relative contribution of GnRH and dopamine in the control of GtH secretion in loach and common carp, and indicate in particular that the more intense dopaminergic inhibitory control of GtH release in common carp modifies the responsiveness of the pituitary to GnRH peptides.

Hydration of carbon dioxide by carbonic anhydrase: internal proton transfer of Zn2+-bound HCO3-

Proton transfer within HCO3- has been examined under various conditions through molecular orbital methods: partial retention of diatomic differential overlap and 4-31G self-consistent field programs. These conditions include the absence or presence of Zn2+, Zn2+(NH3)3, or a water ligand on Zn2+. In addition, 4-31G+ and some MP2/4-31G results are obtained. The use of Be2+ to simulate Zn2+ reproduces reaction pathways and energy barriers, except for marginal cases. The barrier of 35.6 kcal/mol for direct internal proton transfer is reduced to 3.5 kcal/mol when one water molecule, not bound to Zn2+, is included for proton relay and to 1.4 kcal/mol when two such water molecules are included. In the enzyme, either Thr-199 or solvent molecules could perform this relay function. Our results favor this facilitated proton transfer over a mechanism in which Zn2+-bound OH- attacks CO2, a bidentate intermediate forms, and the OH moiety of the resulting HCO3- dissociates from Zn2+, thus leaving one of the oxygens of the original CO2 as a ligand to Zn2+.