Investigation of the binding behavior of bioactive 7-methoxyflavone to human serum albumin by coupling multi-spectroscopic with computational approaches

The natural flavonoids with bioactivity as secondary plant metabolites are mostly found in fruits, vegetables, tea and herbs, the distribution and bioavailability of which in vivo depends on the interaction and successive binding with carrier proteins in the systemic circulation. In this paper, the binding behavior of bioactive 7-methoxyflavone (7-MF) with human serum albumin (HSA) was studied with the aid of the combination of multi-spectroscopic methods, molecular docking and molecular dynamic simulation. The results of multi-spectroscopic experiments revealed that 7-MF interacted with HSA predominantly via fluorescence static quenching and the microenvironment around the fluorophore Trp residues in HSA became more hydrophilicity with the binding of 7-MF. Thermodynamic analysis demonstrated that hydrogen bonds and van der Waals forces played a dominant role in stabilizing the HSA-7-MF complex. Moreover, the docking experiment and molecular dynamic simulation further confirmed that 7-MF could enter the active cavity of HSA and caused more stable conformation and change of secondary structure of HSA through forming hydrogen bond. The exploration of the mechanism of 7-MF binding to HSA lights a new avenue to understand the stability, transport and distribution of 7-MF and 7-MF may hold great potential to be extended as a promising alternative of dietary supplements or pharmaceutical agents.

Predictive capability of material screening by fast neutron activation analysis using laser-driven neutron sources

Bright, short-pulsed neutron beams from laser-driven neutron sources (LANSs) provide a new perspective on material screening via fast neutron activation analysis (FNAA). FNAA is a nondestructive technique for determining material elemental composition based on nuclear excitation by fast neutron bombardment and subsequent spectral analysis of prompt γ-rays emitted by the active nuclei. Our recent experiments and simulations have shown that activation analysis can be used in practice with modest neutron fluences on the order of 10⁵ n/cm², which is available with current laser technology. In addition, time-resolved γ-ray measurements combined with picosecond neutron probes from LANSs are effective in mitigating the issue of spectral interference between elements, enabling highly accurate screening of complex samples containing many elements. This paper describes the predictive capability of LANS-based activation analysis based on experimental demonstrations and spectral calculations with Monte Carlo simulations.

Imidazole Compounds: Synthesis, Characterization and Application in Optical Analysis

Imidazole is a five-membered heterocyclic ring containing three carbon atoms, two nitrogen atoms, and two double bonds. Among two nitrogen atoms, one of which carries with a hydrogen atom is a pyrrole-type nitrogen atom, another is a pyridine type nitrogen atom. Hence, the imidazole ring belongs to the π electron-rich aromatic ring and can accept strong suction to the electronic group. Moreover, the nitrogen atom of the imidazole ring is coordinated with metal ions to form metal-organic frameworks. In recent years, because of imidazole compounds' unique optical properties, their applications have attracted more and more attention in optical analysis. Thus, this review has summarized the synthesis, characterization, and application with emphasis on the research progress of imidazole compounds in optical analysis, including fluorescence probe, colorimetric probe, electrochemiluminescence sensor, fiber optical sensor, surface plasmon resonance, etc. This paper will suggest the direction for the development of imidazole-containing sensors with high sensitivity and selectivity.

A novel symmetrical imidazole-containing framework as a fluorescence sensor for selectively detecting silver ions

In this study, a novel and highly efficient "turn-off" fluorescence imidazole-based sensor (BIB) with a symmetric structure was synthesized by a four-step reaction, from o-phenylenediamine, 6-bromo-2-pyridinecarboxaldehyde, and 1-bromohexane. The sensing mechanism was confirmed via fluorescence titration, HRMS, and ¹HNMR techiniques. The results showed that the binding ratio of BIB and Ag⁺ was 1 : 1 in a DMF-HEPES (pH 7.4) solution (9 : 1, v/v). The fluorescence response of BIB exhibited a good linear response within the Ag⁺ concentration ranging from 2 × 10^-7 to 8 × 10^-6 mol L^-1, and the limit of detection was calculated to be 4.591 × 10^-8 mol L^-1. BIB was successfully applied to the detection of Ag⁺ in water samples with recoveries of 97.25-109.50% and relative standard deviations (RSD) of 1.14-2.45%. In addition, BIB can successfully be applied to qualitatively and quantitatively identify Ag⁺ in water by test paper strips of BIB, which is fast and convenient. This provides a possible potential for the rapid monitoring of metal ions by sensors in environmental research.

Facile synthesis of an aggregation-induced emission (AIE) active imidazoles for sensitive detection of trifluralin

A novel imidazoles fluorescent probe (2) was synthesized from vanillin, o-phenylenediamine, and N,N-diphenylcarbamyl chloride. Its structure was characterized by fluorescence spectra, UV-Vis spectra, ¹H NMR, ¹³C NMR, and high-resolution mass spectrometry (HRMS). Moreover, its aggregation-induced emission (AIE) feature was investigated in THF/MeOH solution. Furthermore, the fluorescence quenching experimental results suggest that compound 2 is the potential fluorescent probe of small organic molecules showing high selectivity and sensitivity for nitroaromatic compounds. In addition, the probe could be applied in the determination of trifluralin with fast response and stability. The fluorescence response of the probe exhibited a good linear correlation with the concentration of trifluralin ranging from 10 to 100 μM, and the limit of detection (LOD) was as low as 5.066 μM. Finally, the probe was successfully utilized to determine the amount of trifluralin in real samples, and the recoveries were 91.1% to 111.2%, indicating the applicability and reliability of the probe.

[Comparisons of prevalence and clinical and environmental characteristics between Tibetan and Han Women with polycystic ovarian syndrome in Tibetan Plateau]

Objective: By the preliminary comparison study on the constituent ratio and clinical characteristics of polycystic ovary syndrome (PCOS) in Tibetan and Han women in Tibetan Plateau, we aimed to find the relevance of its pathogenic factors, and to guide the treatment of PCOS in the plateau region and improve the prognosis. Methods: The general situation and clinical data of 165 patients who were diagnosed with PCOS from December 1, 2015 to November 30, 2016 in the Department of Obstetrics and Gynecology of the People's Hospital of Tibet Autonomous Region were analyzed retrospectively. The prevalence of PCOS among Tibetan and Han women in Tibetan Plateau were compared. Results: (1) A total of 1 520 patients were treated in the Tibet Autonomous Region People's Hospital gynecological endocrinology clinics in one year (Tibetan 865 cases, Han 617 cases, other ethnic groups 38 cases), of which patients with PCOS accounted for 10.9% (165/1520). (2) The incidence of Tibetan PCOS patients with oligomenorrhea, infertility, amenorrhea, acne, hairy, LH/FSH inverted, overweight (BMI≥24), and waist circumference >80 cm were 21.2% (35/165), 20.6% (34/165), 16.4% (27/165), 28.5% (47/165), 17% (28/165), 38.2% (63/165), 23.6% (39/165), and 36.4% (60/165), respectively. The incidence of Han PCOS patients with oligomenorrhea, infertility, amenorrhea, acne, hairy, LH/FSH inverted, overweight (BMI≥24), and waist circumference >80 cm were 7.9% (13/165), 10.3% (17/165), 9.1% (15/165), 15.2% (25/165), 9.7% (16/165), 14.5% (24/165), 10.9% (18/165) and 19.4% (32/165), respectively. The proportion of high testosterone in Tibetan PCOS patients was higher than that in Han PCOS patients with statistically significant. (3) The chief complaint of Tibetan PCOS patients were oligomenorrhea and infertility, and the chief complaint of Han PCOS patients were infertility and amenorrhea. (4) The constituent ratio of outpatient clinics in Nyingchi who were with PCOS at an average elevation of about 3 000 meters in the Tibetan Plateau was 7.9% (13/165), and the average constituent ratio in Lhasa, Xigatse and Nagqu over 3 500 meters above sea level was 35.8% (59/165), 16.9% (28/165) and 15.8% (26/165), respectively. Conclusion: The prevalence of PCOS in Tibetan areas is slightly higher than that in the international community. The clinical manifestations of Tibetan patients with PCOS are significantly different from those of Han patients with PCOS. The higher the altitude, the higher the incidence of PCOS.

Characterization of urinary biomarkers and their relevant mechanisms of zoledronate-induced nephrotoxicity using rats and HK-2 cells

The aim of this study was to identify biomarkers of zoledronate-induced nephrotoxicity and to further characterize the mechanisms underlying this process by analyzing urinary metabolites. Twenty-four rats were randomly divided into four groups containing four (two control groups) or eight rats (two zoledronate groups) per group. The rats were injected intravenously with saline or zoledronate (3 mg/kg) singly (single, 3 weeks) or repeatedly eight times (3 weeks/time, 24 weeks). Serum blood urea nitrogen, serum creatinine, creatinine clearance, and kidney injury observed by hematoxylin and eosin and immunohistochemical staining were changed only in the repeated zoledronate group (3 mg/kg, 3 weeks/time, 24 weeks). Urinary levels of S-adenosylmethionine, S-adenosylhomocysteine, l-cystathionine, l-γ-glutamylcysteine, and glutathione related to glutathione metabolism and fumaric acid and succinic acid related to the tricarboxylic acid cycle in the zoledronate-treated group (3 mg/kg, 3 weeks/time, 24 weeks) were significantly lower than those in the control group, suggesting that zoledronate may cause cellular oxidative stress. Besides, urinary levels of uracil and uridine related to pyrimidine metabolism also decreased after zoledronate treatment (3 mg/kg, 3 weeks/time, 24 weeks), while the levels of hypoxanthine related to purine metabolism, histamine related to histamine metabolism, and several amino acids were significantly increased. Moreover, zoledronate-induced enhanced oxidative stress and histamine overproduction were confirmed by reactive oxygen species (ROS) and histamine measurement in a human proximal tubular cell line. Taken together, zoledronate-induced nephrotoxicity may be attributed to it inducing perturbations in glutathione biosynthesis and the tricarboxylic acid cycle, further causing ROS overproduction, oxidative stress, and cellular inflammation, thereby leading to nephrotoxicity.

An alternative laser driven photodissociation mechanism of pyrrole via πσ*1∕S0 conical intersection

A first principles quantum dynamics study of N-H photodissociation of pyrrole on the S₀-¹πσ^*(A21) coupled electronic states is carried out with the aid of an optimally designed UV-laser pulse. A new photodissociation path, as compared to the conventional barrier crossing on the πσ*1 state, opens up upon electronic transitions under the influence of pump-dump laser pulses, which efficiently populate both the dissociation channels. The interplay of electronic transitions due both to vibronic coupling and the laser pulse is observed in the control mechanism and discussed in detail. The proposed control mechanism seems to be robust, and not discussed in the literature so far, and is expected to trigger future experiments on the πσ*1 photochemistry of molecules of chemical and biological importance. The design of the optimal pulses and their application to enhance the overall dissociation probability is carried out within the framework of optimal control theory. The quantum dynamics of the system in the presence of pulse is treated by solving the time-dependent Schrödinger equation in the semi-classical dipole approximation.

Effect of nano structures on the nucleus wetting modes during water vapour condensation: from individual groove to nano-array surface

The geometrical structures of surfaces are important to the formation and growth of nuclei during water vapour condensation. Nucleus wetting modes on grooved surfaces are determined by the intrinsic contact angle and the cross sectional angle.

Effect of surface free energies on the heterogeneous nucleation of water droplet: a molecular dynamics simulation approach

Heterogeneous nucleation of water droplet on surfaces with different solid-liquid interaction intensities is investigated by molecular dynamics simulation. The interaction potentials between surface atoms and vapor molecules are adjusted to obtain various surface free energies, and the nucleation process and wetting state of nuclei on surfaces are investigated. The results indicate that near-constant contact angles are already established for nano-scale nuclei on various surfaces, with the contact angle decreasing with solid-liquid interaction intensities linearly. Meanwhile, noticeable fluctuation of vapor-liquid interfaces can be observed for the nuclei that deposited on surfaces, which is caused by the asymmetric forces from vapor molecules. The formation and growth rate of nuclei are increasing with the solid-liquid interaction intensities. For low energy surface, the attraction of surface atoms to water molecules is comparably weak, and the pre-existing clusters can depart from the surface and enter into the bulk vapor phase. The distribution of clusters within the bulk vapor phase becomes competitive as compared with that absorbed on surface. For moderate energy surfaces, heterogeneous nucleation predominates and the formation of clusters within bulk vapor phase is suppressed. The effect of high energy particles that embedded in low energy surface is also discussed under the same simulation system. The nucleation preferably initiates on the high energy particles, and the clusters that formed on the heterogeneous particles are trapped around their original positions instead of migrating around as that observed on smooth surfaces. This feature makes it possible for the heterogeneous particles to act as fixed nucleation sites, and simulation results also suggest that the number of nuclei increases monotonously with the number of high energy particles. The growth of nuclei on high energy particles can be divided into three sub-stages, beginning with the formation of a wet-spot, increase of contact angle with near-constant contact line, and finally growth with constant contact angle. The growth rate of nuclei also increases with the size of high energy particles.

Tunable multiple layered Dirac cones in optical lattices

We show that multiple layered Dirac cones can emerge in the band structure of properly addressed multicomponent cold fermionic gases in optical lattices. The layered Dirac cones contain multiple copies of massless spin-1/2 Dirac fermions at the same location in momentum space, whose different Fermi velocity can be tuned at will. On-site microwave Raman transitions can further be used to mix the different Dirac species, resulting in either splitting of or preserving the Dirac point (depending on the symmetry of the on-site term). The tunability of the multiple layered Dirac cones allows us to simulate a number of fundamental phenomena in modern physics, such as neutrino oscillations and exotic particle dispersions with E~p(N) for arbitrary integer N.

Antidiabetic effects of duodenojejunal bypass in an experimental model of diabetes induced by a high-fat diet

Background

Obese patients with type II diabetes who undergo bariatric surgery revert to normal blood glucose and insulin levels, and develop a dramatic increase in insulin sensitivity. However, the mechanisms involved are unknown. This study characterized pancreatic islet and duodenojejunal enteroendocrine cells in normal mice and those with diabetes induced by a high-fat diet (HFD) following duodenojejunal bypass (DJB).

Methods

C57BL/6J mice, fed for 8 weeks either a normal diet (n = 10) or a HFD (n = 10) resulting in a hyperglycaemic state, underwent DJB (connection of the distal end of the jejunum to the distal stomach and direction of biliopancreatic secretions to the distal jejunum). Metabolic and immunohistological analyses were carried out on the pancreas and gastrointestinal tract.

Results

A significant decrease in fasting blood glucose was observed in normal-DJB and HFD-DJB mice 1 week after the operation, with improved glucose tolerance at 4 weeks. There were no changes in pancreatic β-cell mass, but an increase in the ratio of α-cell to β-cell mass was observed in the DJB groups. Furthermore, the number of cells expressing Pdx-1, glucagon-like peptide 1, pancreatic polypeptide and synaptophysin was increased in the bypassed duodenum and/or gastrojejunum of the DJB groups.

Conclusion

Both normal and obese diabetic mice that underwent DJB displayed improved glucose tolerance and a reduction in fasting blood glucose, which mimicked findings in obese diabetic patients following bariatric surgery. The present data suggest that an increase in specific enteroendocrine cell populations may play a critical role in normalizing glucose homeostasis.

Initial phase II experience of ipilimumab (IPI) alone and in combination with radiotherapy (XRT) in patients with metastatic castration-resistant prostate cancer (mCRPC)

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Background: IPI is a fully human, monoclonal anti-CTLA-4 antibody capable of enhancing anti-tumor immunity. In preclinical models, XRT releases tumor antigens and enhances anti-tumor activity of CTLA-4 blockade. In the dose escalation part of this Phase I/II trial 10 mg/kg dosing of IPI with or without prior priming by single fraction XRT was feasible. We now report initial phase II results. Methods: 45 patients (pts) with mCRPC and ECOG PS of 0–1 received 10 mg/kg q3 weeks (wks) X 4 of IPI in 3 groups: (1) IPI alone n=16, (2) IPI + XRT n=15 chemotherapy naïve (NoCHEMO), and (3) IPI + XRT n=14 chemotherapy experienced (CHEMO) pts. XRT (800 cGy) was given to up to 3 involved bony sites (GI tract sparing) just prior to starting IPI. PSA was monitored monthly, with scans q 3 months. Endpoints were to confirm safety and an initial assessment of activity. Results: 17 pts (38%) experienced 26 immune-related adverse events (irAEs) including diarrhea/colitis (12), rash/pruritus (6), hepatitis (4), endocrinopathy (4). 11 pts (24%) experienced 13 ≥ Grade 3 irAEs: GI (9; 20%) and hepatitis (4; 9%); all resolved with immunosuppression. 10 of 45 pts (22%; 95% CI 10–34%) had confirmed PSA declines ≥ 50% as follows in the table below. Median time to PSA decline was 5.7 wks (r 3 to 21 wks); median duration 23 wks (r 3 to 84+ wks). In one pt dosed with IPI alone, PSA ≤ 0.05 ng/ml, as well as a CR of bone, nodal and prostate lesions continue for 54+ and 84+ wks, respectively. Conclusions: irAEs in the 10 mg/kg cohorts are similar in type and rate to IPI in melanoma. irAEs and PSA declines occurred in chemotherapy naïve and post chemotherapy patients, and with or without XRT. Addition of XRT to 10 mg/kg is well tolerated. Time to response can be delayed, with a durable median response of 23 wks. Further study of IPI in mCRPC is warranted, with or without XRT as a potential immunosupportive maneuver to augment clinical responses to IPI.

[Table: see text]

[Table: see text]

Prion protein gene (PRNP) polymorphisms in Xinjiang local sheep breeds in China

Amino acid polymorphisms of the prion protein (PrP) gene (PRNP), particularly those occurring at codons 136, 154, and 171 have a significant influence on scrapie pathogenesis in many sheep breeds. We isolated blood samples from 222 sheep representing the eight main local sheep breeds in the Xinjiang Autonomous Region, the territory with the most abundant local sheep breeds in China, to identify the PRNP polymorphisms and to determine whether these breeds were at risk for developing scrapie. A new PRNP polymorphism encoding either glycine (G) or arginine (R) at codon 85 as well as eight previously reported polymorphisms at codons 101, 112, 127, 141, 146, 154, 171, and 189 in other sheep breeds were detected. Interestingly, the alanine (A)/V polymorphism at codon 136 was not observed in this study, all sheep being homozygous for A at this position. While the previously identified polymorphism of argine (R) or histidine (H) at codon 154 was detected, the H polymorphism was rare (2.25%). Four polymorphisms at codon 171 encoding glutamine (Q), R, H, or lysine (K) were detected. The predominant ARQ allele occurred at a high frequency of 77.48%, suggesting an increased risk of scrapie in Xinjiang Autonomous Region.

Moisture Sources in Relation to Conidial Dissemination and Infection by Cladosporium carpophilum Within Peach Canopies

ABSTRACT Cladosporium carpophilum, the causal agent of peach scab, overwinters in lesions on 1-year-old twigs, from which conidia infect the developing fruit during spring and early summer. Twig lesions constitute the sole source of initial inoculum; therefore, the mode of dissemination of conidia from such lesions to the fruit is of considerable interest. In a 4-year study, we determined the relative importance of air- versus water-borne conidia and their interaction with different fruit wetness sources (splash, twig runoff, and dew) in a peach orchard with areas that had been treated or not treated with fungicide the previous year. The rareness of scab twig lesions in the previously sprayed trees implied that fruit infection in these trees would occur primarily by airborne conidia from unsprayed trees nearby (located within the same tree row or the adjacent row). In the unsprayed areas, additional infections could occur by short-distance waterborne dissemination of conidia from locally abundant twig lesions via splashing or runoff. Beginning at calyx fall, individual fruit were protected from splash by rain shields, protected from runoff by cotton wicks placed proximal to the peduncle, or left untreated. Rain shields were adjustable, allowing rain or dew to be excluded selectively. Various combinations of the shield and wick treatments were implemented in the previously sprayed and unsprayed areas, and statistical comparison of fruit scab severity between individual treatments by linear contrasts allowed us to untangle the relative contributions of the various sources of inoculum and fruit wetness. Results showed that aerial dissemination of conidia contributed little to fruit scab development, even in the presence of fruit surface wetness caused by splashing, runoff, or dew. In contrast, waterborne conidia contributed considerably and significantly (P < 0.0001) to disease development. This was due primarily to the importance of splash in disseminating conidia from twig lesions to the fruit, given that exclusion of splashing via rain shields decreased disease severity by >90%. Runoff water from the twig to the fruit via the peduncle also contributed to scab development, as evidenced by the fact that exclusion of runoff by cotton wicks reduced disease severity by 31.6 to 44.9%; however, this effect was not always statistically significant. The exclusion of dew did not reduce scab severity (P > 0.4), suggesting that it played a limited role in infection in the presence of other fruit wetness sources.

Reduced Midseason Pesticide Program for Control of Scab and Plum Curculio in Peach

Risks to peach production from scab (caused by Cladosporium carpophilum) and plum curculio (Conotrachelus nenuphar), two key pests in the southeastern United States, are high until 2 months past petal fall and then decreases during midseason. This suggests that reduced-input pesticide strategies may effectively control both pests during the latter period. In this study, we evaluated midseason pesticide applications according to an alternate-row middle (ARM) spray program in which sprays were applied only to every other tree row while reducing tractor speed and keeping application intervals unchanged relative to conventional spraying of both sides of the trees. In a 2-year trial in a research orchard, conventional sprays of fungicide (primarily sulfur) and insecticide (primarily phosmet) were applied at 10- to 14-day intervals until first cover, followed by continued conventional sprays of fungicide and insecticide (standard), conventional sprays of one pesticide together with ARM sprays of the other pesticide, or combined ARM sprays of both pesticides. Schedules with midseason ARM sprays of both pesticides also were evaluated in two commercial orchards in 2 years. In all experiments, plots receiving combined ARM sprays were equivalent to the standard in fruit quality and control of scab and plum curculio. Combined ARM spraying resulted in lower environmental nontarget effects (as estimated by the Environmental Impact Quotient) and reduced application time by 25 to 33% for each midseason spray and 12.5 to 18.5% for the entire period from petal fall to the preharvest interval.

Pregnancy outcomes of patients who conceived within 1 year after chemotherapy for gestational trophoblastic tumor: a clinical report of 22 patients

OBJECTIVE

The aim of this study was to explore the risk of pregnancy of patients who conceived within 1 year after successful chemotherapy for gestational trophoblastic tumor (GTT).

METHODS

From 1966 to 1996, 22 patients who conceived within 1 year after chemotherapy were followed up and analyzed retrospectively.

RESULTS

Among 22 patients, 9 had term deliveries and 1 had a premature birth, 6 had induced abortion at the patient's request, and 6 had therapeutic abortion because of various indications such as repeated hydatidiform mole (1 case), intrauterine death (1 case), inevitable abortion (1 case), and threatened abortion (3 cases). The fetal loss rate was 27.1% (6/22). The incidence rate of gestational trophoblastic disease (GTD) was 9.1% (2/22). The incidence rate of GTT was 4.5% (1/22). The average interval between completion of chemotherapy and pregnancy was 10.25 months in the group of term pregnancies and 5.86 months in that of fetal loss (P < 0.05), indicating that the longer the interval, the lesser the risk of GTD.

CONCLUSION

The results suggest that contraception for 1 year is necessary in patients with GTT after successful chemotherapy. However, in the case of a patient who conceives within 1 year, it is not necessary to terminate pregnancy, but the pregnancy must be carefully watched.

A novel serotype-specific gene cassette (gltA-gltB) is required for expression of teichoic acid-associated surface antigens in Listeria monocytogenes of serotype 4b

Listeria monocytogenes serotype 4b strains account for about 40% of sporadic cases and many epidemics of listeriosis. Mutations in a chromosomal locus resulted in loss of reactivity with all three monoclonal antibodies (MAbs) which were specific to serotype 4b and the closely related serotypes 4d and 4e. Here we show that this locus contains a serotype 4b-4d-4e-specific gene cassette (3,071 bp) which consists of two genes, gltA and gltB, and is flanked by palindromic sequences (51 and 44 nucleotides). Complete loss of reactivity with the three serotype-specific MAbs resulted from insertional inactivation of either gltA or gltB. The gltA and gltB mutants were characterized by loss and severe reduction, respectively, of glucose in the teichoic acid, whereas galactose, the other serotype-specific sugar substituent in the teichoic acid, was not affected. Within L. monocytogenes, only strains of serotypes 4b, 4d, and 4e harbored the gltA-gltB cassette, whereas coding sequences on either side of the cassette were conserved among all serotypes. Comparative genomic analysis of a serotype 1/2b strain showed that the 3,071-bp gltA-gltB cassette was replaced by a much shorter (528-bp) and unrelated region, flanked by inverted repeats similar to their counterparts in serotype 4b. These findings indicate that in the evolution of different serotypes of L. monocytogenes, this site in the genome has become occupied by serotype-specific sequences which, in the case of serotype 4b, are essential for expression of serotype-specific surface antigens and presence of glucose substituents in the teichoic acids in the cell wall.

A sheep in wolf's clothing: Listeria innocua strains with teichoic acid-associated surface antigens and genes characteristic of Listeria monocytogenes serogroup 4

Listeria monocytogenes serotype 4b has been implicated in numerous food-borne epidemics and in a substantial fraction of sporadic listeriosis. A unique lineage of the nonpathogenic species Listeria innocua was found to express teichoic acid-associated surface antigens that were otherwise expressed only by L. monocytogenes of serotype 4b and the rare serotypes 4d and 4e. These L. innocua strains were also found to harbor sequences homologous to the gene gtcA, which has been shown to be essential for teichoic acid glycosylation in L. monocytogenes serotype 4b. Transposon mutagenesis and genetic studies revealed that the gtcA gene identified in this lineage of L. innocua was functional in serotype 4b-like glycosylation of the teichoic acids of these organisms. The genomic organization of the gtcA region was conserved between this lineage of L. innocua and L. monocytogenes serotype 4b. Our data are in agreement with the hypothesis that, in this lineage of L. innocua, gtcA was acquired by lateral transfer from L. monocytogenes serogroup 4. The high degree of nucleotide sequence conservation in the gtcA sequences suggests that such transfer was relatively recent. Transfer events of this type may alter the surface antigenic properties of L. innocua and may eventually lead to evolution of novel pathogenic lineages through additional acquisition of genes from virulent listeriae.

p55CDC/hCDC20 is associated with BUBR1 and may be a downstream target of the spindle checkpoint kinase

Eukaryotic cells have evolved a mechanism that delays the progression of mitosis until condensed chromosomes are properly positioned on the mitotic spindle. We have been studying genes that regulated the spindle checkpoint in human cells. Enforced expression of human BUBR1, but not a BUBR1 mutant allele, enhances accumulation of mitotic cells. Yeast two-hybrid system and GST-pulldown analyses show that p55CDC/hCdc20, a protein known to link spindle checkpoint components such as MAD2 to anaphase promoting complex (APC), interacts with BUBR1. In addition, p55CDC is capable of pulling down BUBR1 in sf-9 cells infected with both p55CDC and His6-BUBR1 recombinant baculoviruses but not in the cells infected with p55CDC baculoviruses or with the baculoviral vector alone. Moreover, immunoprecipitation followed by Western blot analyses confirmed that native p55CDC is associated with BUBR1 in HeLa cells. Spindle checkpoint activation by nocodazole treatment enhances the association between p55CDC and His6-BUBR1. In nocodazole-arrested mitotic cells, both CDC16 and hyperphosphorylated CDC27, two APC components, preferentially associate with His6-BUBR1 resins, but not the control resins. Furthermore, BUBR1 phosphorylates p55CDC in vitro, and the phosphorylation of p55CDC by BUBR1 appears to be correlated with spindle checkpoint activation. Together, our studies strongly suggest that BUBR1 may target APC via p55CDC.

Comparison the efficiency of different surgical procedures for urinary stress incontinence

OBJECTIVE

To analyse the efficiency of two operations for treatment of urinary stress incontinence (USI).

METHODS

The clinical data of 95 USI cases or accompany USI treated by surgical procedures (Kelly operation 63 cases, Colposuspension 32 cases) was analysed retrospectively in our department.

RESULTS

The cure rates during three months after operation were 92.9% in Colposuspension group and 68.9% in Kelly operation group (P < 0.05), and decreased to 73.7% and 57.5% one year after operation in Colposuspension group and Kelly operation group respectively (P > 0.05). Abnormal senses rates of sexual intercourse was 3.7% in Colposuspension and 7.3% in Kelly operation group. The length of retaining Foley catheter after Colposuspension was more than Kelly operation.

CONCLUSION

The cure rate during three months after Colposuspension is better than Kelly operation. But the cure rates during one year after surgery are the same in two groups.

[Surgical treatment of patients with stage IV a liver carcinoma]

OBJECTIVE

To study the result of surgical treatment of patients with stage IV a primary liver carcinoma (PLC).

METHODS

Twenty-seven patients with stage IV a PLC treated in 1989-1998 were retrospectively studied. The patients could be divided into 2 groups: (1) The resected group(19 cases) and (2) cytoreductive group(8 cases). Intra-operative B-ultrasound was used to prevent missing of any tumor nodules. Unresectable residual nodules were treated by ethanol injection. Multidisciplinary treatment was given in the perioperative period.

RESULTS

The overall 1-, 2- and 3-year survival rate of the 27 patients was 71.4%, 55.6% and 7.7% respectively. The 1-, 2- and 3-year survival rate of the resected and cytoreductive group of patients was 73.3%, 58.3%, 10.0% and 66.7%, 50.0%, 0% (P > 0.05) respectively. Complications occurred in 22.0% of the treated patients. There was no operative and hospitalization mortality.

CONCLUSIONS

Surgical resection or cytoreductive operation with adjuvant therapy is effective as the first choice of treatment for stage IV a PLC.

Transforming activity of receptor tyrosine kinase tyro3 is mediated, at least in part, by the PI3 kinase-signaling pathway

Protein tyrosine phosphorylation is an integral part of cytokine-induced proliferation and differentiation of hematopoietic cells. The authors previously reported cloning and characterization of the receptor tyrosine kinase Tif, also termed Tyro3. Using the yeast 2-hybrid technology, they recently identified that the p85 subunit of phosphatidylinositol 3-kinase (PI3 kinase) interacted with the cytoplasmic domain of Tyro3. On treatment with epidermal growth factor (EGF), NIH3T3 cells expressed EGFR/Tyro3 (a fusion receptor with the extracellular domain from epidermal growth factor receptor and the transmembrane and cytoplasmic domains from Tyro3), and EGFR/Tyro3 was rapidly phosphorylated on tyrosine residues. The interaction between Tyro3 and p85 was also confirmed by glutathione S-transferase (GST) pull-down experiments. Co-immunoprecipitation followed by Western blot analysis revealed that PI3 kinase was associated with and phosphorylated by the activated Tyro3. Tyro3-associated PI3 kinase exhibited an enhanced kinase activity. In addition, EGF treatment of EGFR/Tyro3-expressing cells led to enhanced phosphorylation of Akt, a downstream component of PI3 kinase. Treatment of NIH3T3 cells expressing a full length of rat Tyro-3, but not NIH3T3 cells, with protein S also resulted in phosphorylation of Akt. Soft agar colony assays showed that the addition of EGF to EGFR/Tyro3-transfected cells, but not to the parental NIH3T3 cells, resulted in a concentration-dependent increase in the formation of anchorage-independent colonies. Tyro3-mediated transformation of NIH3T3 cells was significantly blocked by wortmannin, a PI3 kinase-specific inhibitor. Results of these combined studies strongly suggested that the oncogenic transforming ability of Tyro3 was mediated at least in part by the PI3 kinase pathway. (Blood. 2000;95:633-638)

BUBR1 phosphorylation is regulated during mitotic checkpoint activation

Eukaryotic cells have evolved a mechanism that delays the progression of mitosis until condensed chromosomes are properly positioned on the mitotic spindle. To understand the molecular basis of such monitoring mechanism in human cells, we have been studying genes that regulate the mitotic checkpoint. Our early studies have led to the cloning of a full-length cDNA encoding MAD3-like protein (also termed BUBR1/MAD3/SSK1). Dot blot analyses show that BUBR1 mRNA is expressed in tissues with a high mitotic index but not in differentiated tissues. Western blot analyses show that in asynchronous cells, BUBR1 protein primarily exhibits a molecular mass of 120 kDa, and its expression is detected in most cell lines examined. In addition, BUBR1 is present during various stages of the cell cycle. As cells enter later S and G2, BUBR1 levels are increased significantly. Nocodazole-arrested mitotic cells obtained by mechanical shake-off contain BUBR1 antigen with a slower mobility on denaturing SDS gels. Phosphatase treatment restores the slowly migrating band to the interphase state, indicating that the slow mobility of the BUBR1 antigen is attributable to phosphorylation. Furthermore, purified recombinant His6-BUBR1 is capable of autophosphorylation. Our studies indicate that BUBR1 phosphorylation status is regulated during spindle disruption. Considering its strong homology to BUB1 protein kinase, BUBR1 may also play an important role in mitotic checkpoint control by phosphorylation of a critical cellular component(s) of the mitotic checkpoint pathway.

Human Bub1: a putative spindle checkpoint kinase closely linked to cell proliferation

Eukaryotic cells have evolved a mechanism that delays the onset of anaphase until chromosomes are properly positioned on the spindle. To understand the molecular basis of such surveillance mechanism in human cells, we have cloned a full-length cDNA encoding a putative mitotic checkpoint kinase termed hBub1. Sequence comparison reveals that hBub1 is a structurally conserved protein, sharing 23% amino acid residue identity with BUB1 of budding yeast. In addition, the NH2-terminal portion (161 amino acids) of hBub1 shows a significant homology to yeast MAD3, a protein also known to be involved in the mitotic checkpoint response pathway. Northern blot analyses show that the hBub1 mRNA level is abundantly expressed in tissues or cells with a high mitotic index. When Dami cells undergo terminal differentiation after treatment with phorbol ester, hBub1 expression in this cell line is down-regulated rapidly. The hBub1 protein level is low in G1 and remains relatively constant in S, G2, and M phases. Immunofluorescence analysis shows that hBub1 protein colocalizes with a centromere-kinetochore antigen CREST in interphase, mitotic prophase, and nocodazole-treated cells. Antibody electroporation experiments show that hBub1 is an important component of the spindle checkpoint pathway. Furthermore, fluorescence in situ hybridization analysis maps the hBub1 gene to chromosome 2q12-13. Our studies suggest that hBub1 expression is restricted to proliferating cells and appears to be involved in regulating cell cycle progression. The molecular cloning of hBub1 cDNA will facilitate the study of its role in spindle checkpoint control as well as its potential role in certain genetic disorders.