[Research advances in myopic children with dry eye]

Myopia is a global public health issue, particularly prevalent in China, with a rising trend in recent years. The increased use of computers, smartphones, and video display terminals has led to frequent dry eye symptoms, such as blinking, among myopic students. Studies have revealed a higher incidence of dry eye in myopic children compared to emmetropic children, significantly impacting their learning and quality of life. However, ophthalmologists have traditionally focused more on the prevention and control of myopia, often neglecting ocular surface health awareness in children. It is essential to understand the potential impact of myopia on dry eyes in children and whether there is a difference in dry eye prevalence. This article reviews the current state of research on childhood myopia-related dry eye, encompassing epidemiology, pathogenesis, and risk factors, aiming to provide clinical reference for intervention, prevention, and precise treatment of dry eyes in myopic children.

[Controversies and prospects for surgical treatment of pancreatic neuroendocrine neoplasms with liver metastases]

The incidence of pancreatic neuroendocrine neoplasm(pNEN) increased over the past two decades. Liver metastasis, the most common type of distal metastasis, is also one of the most important prognostic factors. Although several medical treatments, including biotherapy, chemotherapy, targeted therapy, peptide receptor radionuclide therapy and locoregional therapy, are available for pNEN with liver metastases, surgery is still the only possible treatment for cure. Currently, there are several controversies as regards surgical treatment for pNEN with liver metastases. These controversies include, but are not limited to, whether surgical resection is appropriate for pancreatic neuroendocrine tumor G3 with liver metastases, how to classify primary lesion and hepatic metastases comprehensively and accurately, what is the optimal surgical strategy for type Ⅱ liver metastases, who can benefit greatly from cytoreduction, and how to refine the Milan criteria for liver transplantation. This article aims to discuss those main controversies and provide prospects for future clinical trials.

Elevated TGFβ signaling contributes to cerebral small vessel disease in mouse models of Gould syndrome

Cerebral small vessel disease (CSVD) is a leading cause of stroke and vascular cognitive impairment and dementia. Studying monogenic CSVD can reveal pathways that are dysregulated in common sporadic forms of the disease and may represent therapeutic targets. Mutations in collagen type IV alpha 1 (COL4A1) and alpha 2 (COL4A2) cause highly penetrant CSVD as part of a multisystem disorder referred to as Gould syndrome. COL4A1 and COL4A2 form heterotrimers [a1α1α2(IV)] that are fundamental constituents of basement membranes. However, their functions are poorly understood and the mechanism(s) by which COL4A1 and COL4A2 mutations cause CSVD are unknown. We used histological, molecular, genetic, pharmacological, and in vivo imaging approaches to characterize central nervous system (CNS) vascular pathologies in Col4a1 mutant mouse models of monogenic CSVD to provide insight into underlying pathogenic mechanisms. We describe developmental CNS angiogenesis abnormalities characterized by impaired retinal vascular outgrowth and patterning, increased numbers of mural cells with abnormal morphologies, altered contractile protein expression in vascular smooth muscle cells (VSMCs) and age-related loss of arteriolar VSMCs in Col4a1 mutant mice. Importantly, we identified elevated TGFβ signaling as a pathogenic consequence of Col4a1 mutations and show that genetically suppressing TGFβ signaling ameliorated CNS vascular pathologies, including partial rescue of retinal vascular patterning defects, prevention of VSMC loss, and significant reduction of intracerebral hemorrhages in Col4a1 mutant mice aged up to 8 months. This study identifies a novel biological role for collagen α1α1α2(IV) as a regulator of TGFβ signaling and demonstrates that elevated TGFβ signaling contributes to CNS vascular pathologies caused by Col4a1 mutations. Our findings suggest that pharmacologically suppressing TGFβ signaling could reduce the severity of CSVD, and potentially other manifestations associated with Gould syndrome and have important translational implications that could extend to idiopathic forms of CSVD.

Microstructure, mechanical property and corrosion behavior of porous Ti-Ta-Nb-Zr

In this paper, biomedical porous Ti–Nb–Ta–Zr with 40% porosity and 166 ± 21 μm macro-pore size was successfully fabricated by space holder method. The microstructure, Vickers hardness, compressive and electrochemistry behavior were studied. It results that a few second phases exist in β matrix of the porous Ti–Nb–Ta–Zr. Its Young's modulus is 0.8 GPa, close to 0.01–3 GPa for trabecular bone. The total recovery strain ratio and pseudoelastic strain ratio are 8.8% and 2.7%, respectively. It fails mainly by brittle cleavage with the fan-shaped and smooth cleaved facets. Although, local ductile fracture by a few dimples and a small amount of transcrystalline fracture with the cleavage of similarly oriented laths in a colony are observed on the fracture surface. The impedance spectrum of porous Ti–Nb–Ta–Zr has the characteristics of half capacitive arc resistance, showing good corrosion resistance in SBF solution.

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Porous Ti–Nb–Ta–Zr alloy with mainly β phase was fabricated by space holder method.

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Porous Ti alloy with 40% porosity and 166 ± 21 μm macro-pore size failed by brittle cleavage.

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The total recovery strain ratio and pseudoelastic strain ratio are 8.8% and 2.7%, respectively.

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The Young's modulus of porous TNTZ is 0.8 GPa, close to trabecular bone.

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The impedance spectrum of porous TNTZ shows good corrosion resistance in SBF solution.

[Clinical pathologic analysis on 3 724 cases of salivary gland tumors]

Objective: To investigate the incidence and proportion of salivary gland tumors in order to provide new thinking for clinical diagnosis and treatment. Methods: Collected 3 724 cases salivary gland tumors diagnosed by Pathology Department of Hospital of Stomatology, Jilin University from January 1961 to December 2016. The pathological diagnosis referred to the fourth edition of head and neck-salivary gland tumor histopathological classification standard of WHO. The database was established with Microsoft Excel and analyzed with SPSS 18.0. Made a retrospective analysis and comparison on the numbers of all cases in terms of types, site, gender and age and estimate the trend with the time interval of 8 years, and then make a judgement of the trend of salivary tumors. Results: The benign tumors were more common than the malignant among all periods, the proportion of all tumors was about 2.92∶1; The top three benign tumors were polymorphous adenoma [73.78% (2 046/2 773)], Warthin tumor [15.80% (438/2 773)] and base cell adenoma [8.37% (232/2 773)]. Polymorphous adenoma took up 54.94% (2 046/3 724) of all tumors. The top three malignant tumors were mucous epidermoid carcinoma [31.44% (299/951)], adenoid cystic carcinoma [26.92% (256/951)] and adenocarcinoma [11.88% (113/951)]. As for sex, male female ratio was 0.83∶1. As for site, the pathogenic site of tumors was mainly in parotid gland [63.75% (2 374/3 724)], followed by palatal gland [16.50% (615/3 724)], then submandibular gland [12.67% (472/3 724)]; As for age, the common age was between 51 and 60 years old [23.74% (884/3 724)], followed by 41 to 50 years old [21.56%(803/3 724)]. Conclusions: The incidence of benign and malignant salivary gland tumor increased in the 56 years. Females showed a higher incidence. The majority tumors occurred in parotid gland. The most common salivary gland tumor was pleomorphic adenoma and the most common malignant tumor was mucous epidermoid carcinoma. The most common age was in 51-60 years old period.

Electroless fabrication and supercapacitor performance of CNT@NiO-nanosheet composite nanotubes

Composite nanostructures consisting of porous NiO nanosheets on carbon nanotubes (CNTs) are fabricated using a facile and low-cost electroless plating method. The CNTs, modified by a polymer, are adopted as the template upon which porous Ni nanosheets are grown using electroless plating. This is followed by removal of the polymer layer and oxidation of the Ni by controlled thermal annealing. The effect of reductant concentration on the morphology of the NiO nanosheets is studied. The electrochemical characteristics of the nanostructures are measured using chronopotentiometry. Experimental measurements show that the NiO nanosheet covered CNT composite nanostructures exhibit a relatively high specific capacitance of 1177 F g(-1) at a discharge current density of 2 A g(-1), while retaining 89.2% of its initial capacitance at a current density of 2 A g(-1) after 1000 cycles.

Molecular dynamics simulation of the electrically induced spreading of an ionically conducting water droplet

Molecular dynamics simulations are applied to study the spreading behavior of a nanosized water droplet that contains freely moving Na(+)/Cl(-) ions subject to an imposed electric field parallel to a solid surface. Results show that the positive and negative ions move relatively freely in response to an applied electric field, whereas polar water molecules realign themselves. These localized behaviors of the ions and the polar molecules are affected by both the applied electric field strength and the ion concentration, which in turn determine the deformation and spreading of the droplet on a solid substrate. The presence of the freely moving ions causes the ion-containing droplet to spread differently from a droplet of pure water. In a weak electric field of 0.05 V/Å, a droplet of a lower ion concentration spreads asymmetrically and the spreading asymmetry is considerably smaller than that associated with a pure water droplet of the same size. In a stronger field of 0.1 V/Å, a droplet of a higher ion concentration spreads symmetrically and completely wets the solid surface whereas a less ionically conducting droplet undergoes an asymmetric-to-symmetric transition in spreading until it reaches equilibrium.

Molecular dynamics simulation of nanosized water droplet spreading in an electric field

Molecular dynamics (MD) simulations are performed for the spreading of a nanosized water droplet on a solid substrate subject to a parallel electric field. A combined electrostatic and Lennard-Jones potential is employed to represent the intermolecular interactions. Results show that in response to the applied field, polar water molecules realign themselves and this microscopic reorientation of molecular dipoles combines with the intermolecular forces to produce a macroscopic deformation of a free spherical water droplet into an ellipsoid. The applied field has a strong effect on the spreading of the water droplet on a solid substrate. For a weaker parallel field, the droplet spreading is asymmetric with the leading contact angle being greater than the trailing contact angle. With an increase in field strength, this asymmetry continues to increase, culminates, and then decreases until it disappears. The symmetric spreading remains with a further increase in the field strength until the saturation point is reached. This transition from the asymmetric to symmetric spreading is a manifestation of the interaction of the electric field with polar water molecules and the intermolecular forces within the droplet and between the water and solid; the interaction also leads to a change in hydrogen bonds along the droplet surface. The dynamics of the droplet spreading is entailed by the electrically induced motion of molecules along the liquid surface toward the solid substrate and is controlled by a competing mechanism among the electric, water-water, and water-solid intermolecular forces.

Inheritance and fine mapping of a restorer-of-fertility (Rf) gene for the cytoplasmic male sterility in soybean

The cytoplasmic male sterility (CMS) line FuCMS5A and its restorer line FuHui9 were crossed to produce a segregating F(2) population for pollen fertility assay and the genetic mapping of restorer-of-fertility (Rf) gene. Results showed that the individual F(2) plants were fertile or semi-fertile based on their pollen fertility characteristics. The average ratios of viable pollen were 96.90% and 50.00% for each class of individuals. The segregation of F(2) plants showed a good fit to a 1:1 ratio, which reflects a typical heredity pattern of gametophytic CMS with fertility restorer being controlled by a single dominant gene. Using bulk segregation analysis (BSA) and genetic mapping, the Rf gene was mapped on molecular linkage group J (chromosome 16), between the simple sequence repeat (SSR) makers BARCSOYSSR-16-1064 and BARCSOYSSR-16-1082 with the distances of 0.59 and 0.83 cM, respectively. Four SSR markers (BARCSOYSSR-16-1070, Sctt011, BARCSOYSSR-16-1076 and BARCSOYSSR-16-1077) were cosegregating with this Rf gene in the mapping population. These makers will greatly facilitate the maker assisted selection procedures in CMS breeding programs and it lays a foundation for further map-base cloning of the Rf gene.

Reversible twinning in pure aluminum

Twinning in metals is normally a permanent plastic deformation mechanism. Here we report reversible twinning in high stacking fault energy (SFE) aluminum. Twinning and spontaneous detwinning at the crack tip have been captured in situ during tensile straining under a transmission electron microscope. Both the in situ observation and the molecular dynamics simulations reveal a two-stage detwinning process. The high propensity for detwinning is due to the high SFE and the low frictional forces against the detwinning partial dislocations in Al. This discovery of reversible twinning has implications for the deformation of other high SFE materials.

Effect of intracellular trehalose in Cryptococcus laurentii and exogenous lyoprotectants on its viability and biocontrol efficacy on Penicillium expansum in apple fruit

AIMS

To improve viability and biocontrol efficacy of Cryptococcus laurentii after freeze drying and in subsequent storage.

METHODS AND RESULTS

Viability of C. laurentii was improved after freeze drying and in subsequent storage at 4 or 25 degrees C by using skimmed milk (SM) and sugars (glucose, galactose, sucrose and trehalose) as protectants. Sugars and SM mixed together showed better protection than when they were used separately. Citric acid used as carbon source could induce accumulation of intracellular trehalose in the yeast. The yeast cells with high trehalose level (HT cells) had higher viability than those with low trehalose level (LT cells) after freeze drying and storage for 90 days. After storage for 90 days at 4 degrees C, the HT cells plus SM and sugars as protectant showed a similar biocontrol effect against blue mould rot in apple fruit caused by Penicillium expansum as fresh cells.

CONCLUSIONS

Increasing intracellular trehalose content of C. laurentii and adding exogenous protectant (sugars + SM) could improve its viability and maintain its biocontrol efficacy.

SIGNIFICANCE AND IMPACT OF THE STUDY

The results have a potential value for commercial application of C. laurentii.

Effects of trehalose on stress tolerance and biocontrol efficacy of Cryptococcus laurentii

AIMS

To investigate the effects of internal trehalose on viability and biocontrol efficacy of antagonistic yeast Cryptococcus laurentii under stresses of low temperature (LT), controlled atmosphere (CA) and freeze drying.

METHODS AND RESULTS

The content of trehalose in C. laurentii was increased by culturing the yeast in trehalose-containing medium. Compared with yeast cells with low trehalose level, the yeast cells with high level of internal trehalose not only obtained higher viability, but also showed higher population and better biocontrol efficacy against Penicillium expansum on apple fruit both at 1 degrees C and in CA condition (5% O(2), 5% CO(2), 1 degrees C). After freeze drying, survival of the yeast with high trehalose level was markedly increased when stored at 25 degrees C for 0, 15 and 30 days. Meanwhile, high integrity of plasma membrane was detected in the freeze-dried yeast with high trehalose level by propidium iodide staining.

CONCLUSIONS

Induced accumulation of internal trehalose could improve viability and biocontrol efficacy of C. laurentii under stresses of LT and CA. Moreover, survival of the yeast was also increased as internal trehalose accumulation after freeze drying, and one of the reasons might be that trehalose gave an effective protection to plasma membrane.

SIGNIFICANCE AND IMPACT OF THE STUDY

The results of this experiment show a promising way to improve the biocontrol performance of antagonistic yeasts under the commercial conditions.

Effect of Convection on the Measurement of Thermophysical Properties Using Levitated Droplets

This article discusses the recirculating convection in free droplets levitated by either the electromagnetic forces or the electrostatic forces, and its effect on the measurement of thermophysical properties. In an electromagnetically levitated droplet, strong internal flow results from the vortical Lorentz forces induced by the surrounding coils. These forces are also responsible for free surface deformation. In an electrostatically levitated droplet, however, internal convection originates from the thermal gradient and the electrostatic forces are responsible for surface deformation only. Mathematical models for predicting the convection in these droplets and the surface deformations caused by either the electromagnetic or electrostatic forces are discussed. Results show that internal convection, when present, can have a significant effect on the measured data for the purpose of determining the thermophysical properties. The deformed surface assumes essentially the same oval shape in microgravity for both electromagnetically and electrostatically levitated drops. The deformation mechanism, however, is different. Future research directions in this area are also discussed.

Combination of antagonistic yeasts with two food additives for control of brown rot caused by Monilinia fructicola on sweet cherry fruit

AIMS

To evaluate beneficial effect of two food additives, ammonium molybdate (NH4-Mo) and sodium bicarbonate (NaBi), on antagonistic yeasts for control of brown rot caused by Monilinia fructicola in sweet cherry fruit under various storage conditions. The mechanisms of action by which food additives enhance the efficacy of antagonistic yeasts were also evaluated.

METHODS AND RESULTS

Biocontrol activity of Pichia membranefaciens and Cryptococcus laurentii against brown rot in sweet cherry fruit was improved by addition of 5 mmol l(-1) NH4-Mo or 2% NaBi when stored in air at 20 and 0 degrees C, and in controlled atmosphere (CA) storage with 10% O2 + 10% CO2 at 0 degrees C. Population dynamics of P. membranefaciens in the wounds of fruit were inhibited by NH4-Mo at 20 degrees C after 1 day of incubation and growth of C. laurentii was inhibited by NH4-Mo at 0 degrees C in CA storage after 60 days. In contrast, NaBi did not significantly influence growth of the two yeasts in fruit wounds under various storage conditions except that the growth of P. membranefaciens was stimulated after storage for 45 days at 0 degrees C in CA storage. When used alone, the two additives showed effective control of brown rot in sweet cherry fruit and the efficacy was closely correlated with the concentrations used. The result of in vitro indicated that growth of M. fructicola was significantly inhibited by NH4-Mo and NaBi.

CONCLUSION

Application of additives improved biocontrol of brown rot on sweet cherry fruit under various storage conditions. It is postulated that the enhancement of disease control is directly because of the inhibitory effects of additives on pathogen growth, and indirectly because of the relatively little influence of additives on the growth of antagonistic yeasts.

SIGNIFICANCE AND IMPACT OF THE STUDY

The results obtained in this study suggest that an integration of NH4-Mo or NaBi with biocontrol agents has great potential in commercial management of postharvest diseases of fruit.

Integrated modeling of microwave food processing and comparison with experimental measurements

This paper presents an integrated electromagnetic and thermal model for the microwave processing offood packages. The model is developed by combining the edge finite element formulation of the 3-D vector electromagnetic field in the frequency domain and the node finite element solution of the thermal conduction equation. Both mutual and one-way coupling solution algorithms are discussed. Mutual coupling entails the iterative solution of the electromagnetic field and the thermal field, because the physical properties are temperature-dependent. The one-way coupling is applicable when the properties are temperature independent or this dependence is weak. Mesh sensitivity and shape regularity for the edge element based formulation for computational electromagnetics are discussed in light of available analytical solutions for a simple wave guide. The integrated model has been used to study the electromagnetic and thermal phenomena in a pilot scale microwave applicator with and without the food package immersed in water. The calculated results are compared with the experimentally measured data for the thermal fields generated by the microwave heating occurring in a whey protein gel package, and reasonably good agreement between the two is obtained.

Coherent nano-area electron diffraction

We describe the new coherent nano-area electron diffraction (NED) and its application for structure determination of individual nanostructures. The study is motivated by the challenge and the general lack of analytical techniques for characterizing nanometer-sized, heterogeneous phases. We show that by focusing electrons on the focal plane of the pre-objective lens using a 3rd condenser lens and a small condense aperture, it is possible to achieve a nanometer-sized highly parallel illumination or probe. The high angular resolution of diffraction pattern from the parallel illumination allows over-sampling and consequently the solution of phase problem based on the recently developed ab initio phase retrieval technique. From this, a high-contrast and high-resolution image can be reconstructed at resolution beyond the performance limit of the image-forming objective lens. The significance of NED for nanostructure characterization will be exemplified by single-wall carbon nanotubes and small metallic clusters. Imaging from diffraction patterns, or diffractive imaging, will be demonstrated using double-wall carbon nanotubes.

Size- and shape-dependent energetics of nanocrystal interfaces: experiment and simulation

We study the interface energetics of Ag nanocrystals on a H-passivated Si(111) surface by a transmission electron microscopy experiment and molecular dynamics simulations. The annealed nanocrystals are oriented with Ag(111)||Si(111). Azimuthally, epitaxy is preferred for nanocrystals with an interface larger than a coincident-site-lattice (CSL) cell. The equilibrium orientation, or interface energy minimum, depends on the interface size and shape. For interfaces approaching a CSL cell in size ( approximately 2 nm nanocrystals), fluctuations of a single atom at an interface can lead to large variations in nanocrystal orientations.

Nanostructure evolution during cluster growth: Ag on H-terminated Si(111) surfaces

The size of small clusters has a large effect on cluster growth and structure. Using Ag clusters of sizes from approximately 1 to 10 nm grown on H-Si(111), we found that the cluster structure evolves in stages showing (1) irregular shapes at coverage <or=1 ML (monolayer), (2) mostly single crystal of faceted-hut-like shapes from 2 to 5 ML, and (3) defective disklike islands above 5 ML. We show that the rapid coalescence of small clusters drives the nanostructure transition and leads to a steplike growth of nanoclusters that is different from the predictions of scaling theory.

The flavonoid baicalin inhibits superantigen-induced inflammatory cytokines and chemokines

Excessive release of proinflammatory cytokines mediates the toxic effect of superantigenic staphylococcal exotoxins (SE). Baicalin, a flavone isolated from the Chinese herb Scutellaria baicalensis Georgi and used in China to treat infectious diseases, inhibited SE-stimulated T-cell proliferation (by 98%) and production of interleukin 1beta, interleukin 6, tumor necrosis factor, interferon gamma, monocyte chemotactic protein 1, macrophage inflammatory protein (MIP)-1alpha, and MIP-1beta mRNA and protein by human peripheral blood mononuclear cells. These data suggest that baicalin may be therapeutically useful for mitigating the pathogenic effects of SE by inhibiting the signaling pathways activated by superantigens.

The synthetic peptide WKYMVm attenuates the function of the chemokine receptors CCR5 and CXCR4 through activation of formyl peptide receptor-like 1

The G protein-coupled 7 transmembrane (STM) chemoattractant receptors can be inactivated by heterologous desensitization. Earlier work showed that formly peptide receptor-like 1 (FPRL1), an STM receptor with low affinity for the bacterial chemotactic peptide formyl-methionyl-leucyl-phenylalamine (fMLF), is activated by peptide domains derived from the human immunodeficiency virus (HIV)-1 envelope glycoprotein gp120 and its activation results in desensitization and down-regulation of the chemokine receptors CCR5 and CXCR4 from monocyte surfaces. This study investigated the possibility of interfering with the function of CCR5 or CXCR4 as HIV-1 coreceptors by activating FPRL1. Cell lines were established expressing FPRL1 in combination with CD4/CXCR4 or CD4/CCR5 and the effect of a synthetic peptide, WKYMVm, a potent activator of formyl peptide receptors with preference for FPRL1 was determined. Both CXCR4 and CCR5 were desensitized by activation of the cells with WKYMVm via a staurosporine-sensitive pathway. This desensitization of CXCR4 and CCR5 also attenuated their capacity as the fusion cofactors for HIV-1 envelope glycoprotein and resulted in a significant inhibition of p24 production by cell lines infected with HIV-1 that use CCR5 or CXCR4 as coreceptors. Furthermore, WKYMVm inhibited the infection of human peripheral monocyte-derived macrophages and CD4(+) T lymphocytes by R5 or X4 strains of HIV-1, respectively. These results indicate that heterologous desensitization of CCR5 and CXCR4 by an FPRL1 agonist attenuates their major biologic functions and suggest an approach to the development of additional anti-HIV-1 agents. (Blood. 2001;97:2941-2947)

Stability of modulated-gravity-induced thermal convection in magnetic fields

A stability analysis is presented of modulated-gravity-induced thermal convection in a heated fluid layer subject to an applied magnetic field. The nearest correction to the critical Rayleigh number for both single and multiple frequency oscillating-gravity components is obtained by solving the linearized magnetohydrodynamic equations using the small parameter perturbation technique. The correction depends on both the applied magnetic field and the oscillating frequency. In the absence of an applied magnetic field, the correction depends on the Prandtl number only when the exciting frequency is small. However, it asymptotically approaches zero as the frequency increases, with or without the presence of a magnetic field. The heated fluid layer is more stable with gravity modulation than with any type of wall temperature modulation. The difference becomes smaller with decreasing Prandtl number Pr. This finding is of critical importance in that ground-based experiments with appropriate wall temperature modulations may be conducted to simulate the oscillating-gravity effects on the onset of thermal convection in lower-Prandtl-number fluids. For conducting melts considered for microgravity applications, it is possible to apply an external magnetic field to further inhibit the onset of modulated-gravity-induced thermal convection. This effectiveness increases with the Hartmann number Ha. For large Ha, the nearest correction term R02 approximately Ha2 as the magnetic Prandtl number Pm<<1. However, R02 approximately Ha(4/3) for Ha>>1 and Pm>>1, provided that Ha<0.5pi(Pm/Pr(3/2)), which is satisfied by a majority of space melt experiments. Thus, under normal laboratory conditions applied magnetic fields are more effective in stabilizing a conducting fluid subject to an oscillating-gravity field than one subject to a constant field. If Ha>0.5pi(Pm/Pr(3/2)), R02 approximately -Ha2 for Ha>>1 and Pm>>1 and the magnetic field becomes less effective in stabilizing thermal convection driven by oscillating gravity than that driven by the constant gravity. This is in contrast with the existing studies on thermal convection stability in a magnetic field, which show that marginal stability is independent of Pm and always increases with increasing applied field.

Flavonoid baicalin inhibits HIV-1 infection at the level of viral entry

Baicalin (BA) is a flavonoid compound purified from medicinal plant Scutellaria baicalensis Georgi and has been shown to possess anti-inflammatory and anti-HIV-1 activities. In an effort to elucidate the mechanism of the anti-inflammatory effect of BA, we recently found that this flavonoid compound was able to form complexes with selected chemokines and attenuated their capacity to bind and activate receptors on the cell surface. These observations prompted us to investigate whether BA could inhibit HIV-1 infection by interfering with viral entry, a process known to involve interaction between HIV-1 envelope proteins and the cellular CD4 and chemokine receptors. We found that BA at the noncytotoxic concentrations, inhibited both T cell tropic (X4) and monocyte tropic (R5) HIV-1 Env protein mediated fusion with cells expressing CD4/CXCR4 or CD4/CCR5. Furthermore, presence of BA at the initial stage of HIV-1 viral adsorption blocked the replication of HIV-1 early strong stop DNA in cells. Since BA did not inhibit binding of HIV-1 gp120 to CD4, we propose that BA may interfere with the interaction of HIV-1 Env with chemokine coreceptors and block HIV-1 entry of target cells. Therefore, BA can be used as a basis for developing novel anti-HIV-1 agents.

The flavonoid baicalin exhibits anti-inflammatory activity by binding to chemokines

Baicalin (BA) is a flavonoid compound purified from the medicinal plant Scutellaria baicalensis Georgi and has been reported to possess anti-inflammatory and anti-viral activities. In order to elucidate the mechanism(s) of action of BA, we tested whether BA could interfere with chemokines or chemokine receptors, which are critical mediators of inflammation and infection. We observed that BA inhibited the binding of a number of chemokines to human leukocytes or cells transfected to express specific chemokine receptors. This was associated with a reduced capacity of the chemokines to induce cell migration. Co-injection of BA with CXC chemokine interleukin-8 (IL-8) into rat skin significantly inhibited IL-8 elicited neutrophil infiltration. BA did not directly compete with chemokines for binding to receptors, but rather acted through its selective binding to chemokine ligands. This conclusion was supported by the fact that BA cross-linked to oxime resin bound chemokines of the CXC (stromal cell-derived factor (SDF)-1alpha, IL-8), CC (macrophage inflammatory protein (MIP)-1beta, monocyte chemotactic protein (MCP)-2), and C (lymphotactin (Ltn)) subfamilies. BA did not interact with CX3C chemokine fractalkine/neurotactin or other cytokines, such as TNF-alpha and IFN-gamma, indicating that its action is selective. These results suggest that one possible anti-inflammatory mechanism of BA is to bind a variety of chemokines and limit their biological function.

Isoform-specific insertion near the Grb2-binding domain modulates the intrinsic guanine nucleotide exchange activity of hSos1

Two human hSos1 isoforms (Isf I and Isf II; Rojas et al., Oncogene 12, 2291-2300, 1996) defined by the presence of a distinct 15 amino acid stretch in one of them, were compared biologically and biochemically using representative NIH3T3 transfectants overexpressing either one. We showed that hSos1-Isf II is significantly more effective than hSos1-Isf I to induce proliferation or malignant transformation of rodent fibroblasts when transfected alone or in conjunction with normal H-Ras (Gly12). The hSos1-Isf II-Ras cotransfectants consistently exhibited higher saturation density, lower cell-doubling times, increased focus-forming activity and higher ability to grow on semisolid medium and at low serum concentration than their hSos1-Isf I-Ras counterparts. Furthermore, the ratio of GTP/GDP bound to cellular p21ras was consistently higher in the hSos1-Isf II-transfected clones, both under basal and stimulated conditions. However, no significant differences were detected in vivo between Isf I- and Isf II-transfected clones regarding the amount, stability and subcellular localization of Sos1-Grb2 complex, or the level of hSos1 phosphorylation upon cellular stimulation. Interestingly, direct Ras guanine nucleotide exchange activity assays in cellular lysates showed that Isf II transfectants consistently exhibited about threefold higher activity than Isf I transfectants under basal, unstimulated conditions. Microinjection into Xenopus oocytes of purified peptides corresponding to the C-terminal region of both isoforms (encompassing the 15 amino acid insertion area and the first Grb2-binding motif) showed that only the Isf II peptide, but not its corresponding Isf I peptide, was able to induce measurable rates of meiotic maturation, and synergyzed with insulin, but not progesterone, in induction of GVBD. Our results suggest that the increased biological potency displayed by hSos1-Isf II is due to higher intrinsic guanine nucleotide exchange activity conferred upon this isoform by the 15 a.a. insertion located in proximity to its Grb2 binding region.

Characterization of the p125 subunit of human DNA polymerase delta and its deletion mutants. Interaction with cyclin-dependent kinase-cyclins

The catalytic subunit of human DNA polymerase (pol) delta was overexpressed in an active, soluble form by the use of a baculovirus system in insect cells. The recombinant enzyme was separated from endogenous DNA polymerases by phosphocellulose, Mono Q-Sepharose, and single-stranded DNA-cellulose chromatography. Recombinant DNA pol delta was also purified by immunoaffinity chromatography. The enzymatic properties of the purified catalytic subunit were characterized. The enzyme was active and possessed both DNA polymerase and associated 3' to 5' exonuclease activities. NH2-terminal deletion mutants retained polymerase activity, whereas the core and COOH-terminal deletion mutants were devoid of any measurable activities. Coinfection of Sf9 cells with recombinant baculovirus vectors for pol delta and cyclin-dependent kinase (cdk)-cyclins followed by metabolic labeling with 32Pi showed that the recombinant catalytic subunit of pol delta could be hyperphosphorylated by G1 phase-specific cdk-cyclins. When cdk2 was coexpressed with pol delta in Sf9 cells, pol delta was found to coimmunoprecipitate with antibodies against cdk2. Experiments with deletion mutants of pol delta showed that the NH2-terminal region was essential for this interaction. Coimmunoprecipitation and Western blot experiments in Molt 4 cells confirmed the interaction in vivo. Preliminary experiments showed that phosphorylation of the catalytic subunit of pol delta by cdk2-cyclins had little or no effect on the specific activity of the enzyme.

Clinical and experimental study on therapeutic effect of Weixibaonizhuanwan on gastric precancerous lesions

AIM

To study the therapeutic effect of Weixibaonizhuanwan on gastric precancerous lesions.

METHODS

Thirty-six patients with gastric precancerous lesions were treated with Weixibaonizhuanwan for 3 mo. Thirteen (36.1%) patients presented with mild atrophic gastritis, 14 (38.9%) with moderate atrophic gastritis, and nine (25.0%) with severe atrophic gastritis. Twenty-two (61.1%) and 27 (75.0%) of the cases were accompanied by intestinal metaplasia (IM) and dysplasia (DYS), respectively. Twenty of the 36 patients were men and 16 were women, ranging from 30 to 67 years in age, with 61.1% of the patients being 40-59 years old. The duration of the disease in these patients ranged from 3 mo to 21 years, with 20 (55.6%) patients experiencing durations of the disease between 5 and 10 years. The clinical manifestations of the disease in these patients included fullness of the abdomen (31 cases), abdominalgia (27 cases), anorexia (30 cases), eructation (26 cases), pantothenic acid (6 cases), and loose stool (9 cases). Patients were treated with Weixibaonizhuanwan and symptom improvement, level of atrophy of the gastric mucosa, and IM and DYS progression were analyzed.

RESULTS

After a 3-mo treatment with Weixibaonizhuanwan, seven patients experienced recovery. The treatment was effective in 11 cases, improved symptoms in 13 cases, and was ineffective in five cases. The overall efficacy rate was 86.1%. In patients with mild atrophic gastritis (n = 13), 11 improved into superficial gastritis and two experienced no improvement. In 14 cases of moderate gastritis, four cases improved into superficial gastritis and seven turned into mild atrophic gastritis, with three patients experiencing no improvement. Among severe atrophic gastritis patients (n = 9), five improved into moderate atrophic gastritis after treatment and four experienced no improvement. The overall efficacy rate in chronic atrophic gastritis patients was 77.8%. Among 9 patients with IM, IM disappeared in six cases, whereas three cases showed no improvement after treatment. In cases with moderate IM (n = 10), IM disappeared in two, turned into mild IM in five, and showed no change in three. Out of four cases with IM, one case turned into moderate IM and three showed no change. The overall efficacy rate in IM patients was 63.6%. Out of 16 cases of mild DYS, DYS disappeared in 11, whereas five cases showed no change. Out of nine cases of moderate DYS, DYS disappeared in two and turned into mild DYS in five cases, with two patients experiencing no change after treatment. No improvement was observed in the two cases of severe DYS after treatment. The overall efficacy rate in DYS patients was 66.7%. After treatment, expression of carcinoembryonic antigen (CEA) and proliferating cell nuclear antigen (PCNA) in gastric mucosa significantly decreased (P < 0.01). Before treatment, cancer staging of these patients by positive CEA expression was I, II, III, and IV in 13, 12, 9, and 2 cases, respectively. After treatment, the number of cases per stage changed to 25, 7, 3, and 1, respectively. Similarly, before treatment, staging by positivity of PCNA expression was I, II, III, and IV in 16, 11, 10, and 4 cases, respectively, and changed to 21, 9, 5, and 1, respectively, after treatment.

CONCLUSION

The use of Weixibaonizhuanwan in the treatment of gastric precancerous lesions showed promising therapeutic effects in patients after 3-mo treatments.

Expression and characterization of the small subunit of human DNA polymerase delta

DNA polymerase delta is a heterodimer consisting of a catalytic subunit of 125 kDa and a small subunit of 50 kDa (p50). We have overexpressed p50 in Escherichia coli and have characterized the recombinant protein. p50 was readily overexpressed using the pET vector as an insoluble protein. A procedure was developed for its purification and renaturation. Examination of the physicochemical properties of renatured p50 showed that it is a monomeric protein with an apparent molecular weight of 60,000, a Stokes radius of 34 A, and a sedimentation coefficient of 4.1 S. Its physical properties were indistinguishable from p50 expressed as a soluble protein using the pTACTAC vector. Examination of the effects of recombinant p50 on the activity of DNA polymerase delta showed that p50 is able to slightly stimulate (about 2-fold) the activity of the recombinant 125-kDa catalytic subunit using poly(dA).oligo(dT) as a template in the absence of proliferating cell nuclear antigen. In the presence of proliferating cell nulear antigen, activity is stimulated about 5-fold. Seven stable hybridoma cell lines were established that produced monoclonal antibodies against p50. One of these antibodies (13D5) inhibited the activity of calf thymus DNA polymerase delta. This antibody, when coupled to a solid support, also was found to provide a method for the immunoafffinity purification of recombinant p50 and of DNA polymerase delta from calf thymus or HeLa extracts. Immunoprecipitation and enzyme-linked immunosorbent assays also confirmed that p50 interacts with the catalytic subunit of DNA polymerase delta.

Macrophage-stimulating protein activates Ras by both activation and translocation of SOS nucleotide exchange factor

Macrophage-stimulating protein (MSP) is a chemotactic factor that activates the receptor tyrosine kinase RON. The involvement of Ras in MSP-induced signal transduction was investigated. Here we demonstrate that, in RON-transfected MDCK cells, an active GTP-bound form of Ras was rapidly accumulated by MSP treatment and the Ras-guanine nucleotide exchange activity in SOS immunoprecipitates was concomitantly increased. GAP activity was not changed under the same conditions used. Furthermore, the SH2 domain of adaptor protein GRB2, but not Shc, associated with the activated RON-beta chain, and GRB2-SOS complexes translocated from the cytosol to the membrane upon MSP treatment. These results strongly suggest that MSP activates Ras through RON, and that MSP-induced activation of Ras might be controlled by both the enhancement of catalytic exchange activity of SOS and its translocation to the membrane where its target Ras is localized.

[Abnormal partograph in primipara with vertex presentation]

A prospective study on partograph (cross X type) was carried out in primipara with vertex presentation. There were 50 cases of dystocia in the study group and 50 cases of normal delivery in the control group. The results showed that the latent phase and active period of labor course in study group was significantly longer than the control group (P < 0.001). The speed of cervical dilation and descent of fetal presentation in the study group was marked slower than the control group (P < 0.001). The rate of postpartum hemorrhage, total time of labor, operative delivery rate and neonatal asphyxia rate in the study group were significantly higher than the control group (P < 0.001). After active management 38 cases in the abnormal group were delivered vaginally. It suggested that the use of partography is very important in revealing abnormal labor course and detection of dystocia, guiding the management of labor.

Mitogenic activation of the Ras guanine nucleotide exchange factor in NIH 3T3 cells involves protein tyrosine phosphorylation

We report biochemical evidence that epidermal growth factor and platelet-derived growth factor stimulate the Ras guanine nucleotide exchange factor activity in quiescent NIH 3T3 cells. Moreover, the exchange activity is constitutively enhanced in NIH 3T3 cells transformed by Src and ErbB2 oncogenic tyrosine protein kinases (TPKs), whereas transformation by oncogenic Mos and Raf does not alter the activity. GTPase-activating protein activity was not affected under these conditions. Overexpression of pp60c-Src mutants containing activated and suppressor TPK mutations resulted in stimulation and inhibition of the exchange factor activity, respectively. A TPK inhibitor, genistein, prevented the activation of the exchange factor in epidermal growth factor/platelet-derived growth factor-treated cells and src-transformed cells. Furthermore, the exchange factor activity bound to an anti-phosphotyrosine antibody immunoaffinity column. These findings suggest that the guanine nucleotide exchange factor, but not GTPase-activating protein, plays a major role in the Ras activation in cell proliferation initiated by growth factor receptor TPKs and malignant transformation by oncogenic TPKs and that tyrosine phosphorylation of either the exchange factor or a tightly bound protein(s) may mediate the activation of the exchange factor by these TPKs.

Inhibition of HIV infection by baicalin--a flavonoid compound purified from Chinese herbal medicine

Baicalin (BA), (formulated as 7-D-glucuronic acid-5,6-dihydroxy-flavone), was purified from the plant Scutellaria Baicalensis Georgi. It has been used as a traditional Chinese herbal medicine. The inhibitory effect of BA against human immunodeficiency virus (HIV-1) infection and replication has been studied in vitro. The compound inhibits HIV-1 infection and replication as measured by: (1) a quantitative focal syncytium formation on CEM-ss monolayer cells; and (2) HIV-1 specific core antigen p24 expression and retroviral reverse transcriptase (RT) activity in the HIV-1-infected H9 cells. We have further demonstrated that the enzymatic activity of purified recombinant HIV-1/RT was inhibited by BA. In addition to lymphoid cell lines, the anti-HIV-1 activity of BA was also observed in cultures of primary human peripheral blood mononuclear cells infected with HIV-1 in vitro. Neither cytotoxic nor cytostatic effects on the indicator cells were found under the assay condition. This data suggests that BA may serve as a useful drug for the treatment and prevention of HIV infections.

Nerve growth factor stimulation of the Ras-guanine nucleotide exchange factor and GAP activities

The biological activity of Ras proteins is thought to be controlled by the guanine nucleotide exchange factor and the guanosine triphosphatase activating protein (GAP). Treatment of rat pheochromocytoma PC-12 cells with nerve growth factor (NGF) increased the amount of active Ras guanosine triphosphate complex and stimulated the activities of both the guanine nucleotide exchange factor and GAP. In PC-12 cells that overexpressed the tyrosine kinase encoded by the trk proto-oncogene (a component of the high-affinity NGF receptor), the NGF-induced activation of the regulatory proteins was potentiated. These results suggest that the NGF receptor system enhances the activities of both the guanine nucleotide exchange factor and GAP and that the activation of Ras might be controlled by the balance in activity between these two regulatory proteins.

Decrease in cytokine production by HIV-infected macrophages in response to LPS-mediated activation

The capacity of human monocytes/macrophages (M/M) infected with a human immunodeficiency virus-1 (HIV-1) isolate to produce several immunomodulating cytokines including interleukin-1 alpha (IL-1 alpha), IL-1 beta, tumor necrosis factor-alpha (TNF-alpha), IL-6, IL-8, and macrophage chemoattractant and activating factor (MCAF) was examined. Although HIV infection itself induced significant increases in the level of mRNAs for IL-1 beta, TNF-alpha, IL-6, and IL-8, the levels of lipopolysaccharide (LPS)-induced mRNAs for IL-1 alpha, IL-1 beta, TNF-alpha, IL-6, IL-8, and MCAF were decreased over those of uninfected LPS-stimulated cells. In addition, HIV-infected M/M produced lower amounts of IL-8 protein, as measured by radioimmunoassay over an 18-day culture period. These results suggest that HIV infection generally suppresses the LPS-inducible cytokine production in human M/M. The impact of the role of these cytokines in the immunity and pathogenesis of HIV-1 infection is discussed.

A new class of anti-HIV agents: GAP31, DAPs 30 and 32

Three inhibitors of human immunodeficiency virus (HIV) have been isolated and purified to homogeneity from Euphorbiaceae himalaya seeds (Gelonium multiflorum) and carnation leaves (Dianthus caryophyllus). These proteins, GAP 31 (Gelonium Anti-HIV Protein 31 kDa) and DAPs 30 and 32 (dianthus anti-HIV proteins, 30 and 32 kDa), inhibit HIV-1 infection and replication in a dose-dependent manner with little toxicity to target cells. The therapeutic indices of these compounds are in the order 10(4), suggesting that they may be clinically important agents in the treatment of AIDS. The N-terminal amino acid sequences of these proteins show little homology to those of previously described anti-HIV proteins. The structure-function features of these HIV inhibitors, based on the 40-60 amino acid residues of N-terminal sequences, are examined.

TAP 29: an anti-human immunodeficiency virus protein from Trichosanthes kirilowii that is nontoxic to intact cells

An anti-human immunodeficiency virus (anti-HIV) protein capable of inhibiting HIV-1 infection and replication has been isolated and purified to homogeneity from Trichosanthes kirilowii. This protein, TAP 29 (Trichosanthes anti-HIV protein, 29 kDa), is distinct from trichosanthin [also known as GLQ 223 (26 kDa)] in size, N-terminal amino acid sequence, and cytotoxicity. In addition to three conservative substitutions--namely, Arg-29 to Lys, Ile-37 to Val, and Pro-42 to Ser--a total difference of residues 12-16 was found. TAP 29 yielded -Lys-Lys-Lys-Val-Tyr-, whereas trichosanthin has -Ser-Ser-Tyr-Gly-Val-. Although the two proteins exhibit similar anti-HIV activity, as measured by syncytium formation, p24 expression, and HIV reverse transcriptase activity, they differ significantly in cytotoxicity, as measured by their effects on cellular DNA and protein syntheses. At the dose level of the bioassays, 0.34-340 nM, trichosanthin demonstrates a dose-dependent toxic effect on host cells. TAP 29 displays no toxic effect, even at 100 X ID50, whereas trichosanthin demonstrates 38% and 44% inhibition on cellular DNA and protein synthesis, respectively. These results indicate that the therapeutic index of TAP 29 is at least two orders of magnitude higher than that of trichosanthin. Thus TAP 29 may offer a broader safe dose range in the treatment of AIDS.

[Multicentric carcinoma of the esophagus and double primary malignant neoplasm of the upper alimentary tract--report on 44 patients]

During the past fifteen years, 44 patients with multicentric carcinoma of the esophagus or double primary malignant neoplasm of the upper alimentary tract, collected from 5316 patients with cancer of esophagus or gastric cardia in the same period, were treated in our hospital. The incidence was 0.83%. All were proven by pathology. Exploratory thoracotomy was done in 32 patients and 26 lesions were resected with a resection rate of 81.3%. All patients with cancer resected survived over 1 year, 6 out of 9 survived over 3 years and 2 out of 3, over 5 years. In the 18 patients who received chemotherapy alone, 12 were followed and all died within 1 year. It is shown that multicentric carcinoma of the esophagus or double malignant neoplasm of the upper alimentary tract should be given energetic treatment. Finally, the incidence, diagnosis criteria, diagnosis method, etiology and management are discussed with a review of literature.

Craniopagus parasiticus: a case report of a parasitic head protruding from the right side of the face

An extremely rare case of parasitic head protruding from the right side of the face is presented. It differs from all the other cases previously reported in the literature. The patient had a parasitic head with an abnormal brain, two eyebrows, two underdeveloped eyes, nose, mouth, 12 teeth, a tongue and plenty of hair. The parasitic head was excised. The nature of the embryological abnormalities is discussed and the literature of polygnathism reviewed.