A Mathematical Model of Chlamydial Infection Incorporating Movement of Chlamydial Particles

We present a spatiotemporal mathematical model of chlamydial infection, host immune response, and movement of infectious particles. The resulting partial differential equations model both the dynamics of the infection and changes in infection profile observed spatially along the length of the host genital tract. This model advances previous Chlamydia modelling by incorporating spatial change. Numerical solutions and model analysis are carried out, and we present a hypothesis regarding the potential for treatment and prevention of infection by increasing chlamydial particle motility.     

A Novel Photocatalytic Material for Removing Microcystin-LR under Visible Light Irradiation: Degradation Characteristics and Mechanisms

Background and Purpose

Microcystin-LR (MC-LR), a common toxic species in contaminated aquatic systems, persists for long periods because of its cyclic structure. Ag₃PO₄ is an environment-friendly photocatalyst with relatively good degradation capacity for hazardous organic pollutants. This study aimed to investigate the degradation capacity of Ag₃PO₄ for MC-LR under visible light.

Methods

An Ag₃PO₄ photocatalyst was synthesized by the ion-exchange method and characterized by X-ray diffraction, field-emission scanning electron microscope, and UV-Vis spectrophotometer. MC-LR was quantified in each sample through high-performance liquid chromatograph. The degradation efficiency of MC-LR was affected by initial pH, initial Ag₃PO₄ concentration, initial MC-LR concentration, and recycle experiments. The degradation intermediates of MC-LR were examined by liquid chromatography-mass spectrometry (LC/MS).

Results

The degradation process can be well fitted with the pseudo-first-order kinetic model. The maximum MC-LR degradation rate of 99.98% can be obtained within 5 h under the following optimum conditions: pH of 5.01, Ag₃PO₄ concentration of 26.67 g/L, and MC-LR concentration of 9.06 mg/L. Nine intermediates were detected and analyzed by LC/MS. Three main degradation pathways were proposed based on the molecular weight of the intermediates and the reaction mechanism: (1) hydroxylation on the aromatic ring of Adda, (2) hydroxylation on the diene bonds of Adda, and (3) internal interactions on the cyclic structure of MC-LR.

Conclusion

Ag₃PO₄ is a highly efficient catalyst for MC-LR degradation in aqueous solutions.     

Red Light Combined with Blue Light Irradiation Regulates Proliferation and Apoptosis in Skin Keratinocytes in Combination with Low Concentrations of Curcumin

Curcumin is a widely known natural phytochemical from plant Curcuma longa. In recent years, curcumin has received increasing attention because of its capability to induce apoptosis and inhibit cell proliferation as well as its anti-inflammatory properties in different cancer cells. However, the therapeutic benefits of curcumin are severely hampered due to its particularly low absorption via trans-dermal or oral bioavailability. Phototherapy with visible light is gaining more and more support in dermatological therapy. Red light is part of the visible light spectrum, which is able to deeply penetrate the skin to about 6 mm, and directly affect the fibroblast of the skin dermis. Blue light is UV-free irradiation which is fit for treating chronic inflammation diseases. In this study, we show that curcumin at low concentrations (1.25–3.12 μM) has a strong anti-proliferative effect on TNF-α-induced psoriasis-like inflammation when applied in combination with light-emitting-diode devices. The treatment was especially effective when LED blue light at 405 nm was combined with red light at 630 or 660 nm, which markedly amplified the anti-proliferative and apoptosis-inducing effects of curcumin. The experimental results demonstrated that this treatment reduced the viability of human skin keratinocytes, decreased cell proliferation, induced apoptosis, inhibited NF-κB activity and activated caspase-8 and caspase-9 while preserving the cell membrane integrity. Moreover, the combined treatment also down-regulated the phosphorylation level of Akt and ERK. Taken together, our results indicated that the combination of curcumin with LED blue light united red light irradiation can attain a higher efficiency of regulating proliferation and apoptosis in skin keratinocytes.     

Toll-Like Receptor 7 Inhibits Early Acute Retroviral Infection through Rapid Lymphocyte Responses

Early events during retroviral infection play a critical role in determining the course of infection and pathogenesis, but the mechanisms that regulate this phase of infection are poorly understood. Toll-like receptor 7 (TLR7) is required for promoting germinal center reactions and virus-specific neutralizing antibodies at later time points postinfection, but TLR7''s role in early acute infection has not been determined. By infecting TLR7-deficient mice with a retroviral pathogen, Friend virus (FV), I determined that TLR7 potently inhibits retroviral replication during the first 5 days of infection and is required for rapid secretion of virus-specific IgM and interleukin-10 (IL-10) in response to infection. Although the IgM response was nonneutralizing, plasmas from wild-type mice but not TLR7-deficient mice inhibited FV replication when passively transferred to infected mice, suggesting an indirect mechanism of antibody function. Interestingly, IL-10 was secreted primarily by CD4 T cells, and IL-10-deficient mice also exhibited accelerated early virus spread, demonstrating that this response inhibits acute infection. Surprisingly, TLR7-deficient mice exhibited normal or elevated secretion of proinflammatory cytokines during acute infection, revealing the existence of a TLR7-independent retrovirus-sensing pathway that drives inflammatory cytokine secretion. Together, these results establish a previously unappreciated role for lymphocytes in mediating rapid TLR7-dependent inhibition of early retroviral infection through nonneutralizing IgM and IL-10.     

Lavage with Allicin in Combination with Vancomycin Inhibits Biofilm Formation by Staphylococcus epidermidis in a Rabbit Model of Prosthetic Joint Infection

Background and Aim

The present anti-infection strategy for prosthetic joint infections (PJI) includes the use of antibiotics and surgical treatments, but the bacterial eradication rates are still low. One of the major challenges is the formation of biofilm causing poor bacterial eradication. Recently it has been reported that allicin (diallyl thiosulphinate), an antibacterial principle of garlic, can inhibit bacteria adherence and prevent biofilm formation in vitro. However, whether allicin could inhibit biofilm formation in vivo is unknown. The aim of this study was to investigate the effects of allicin on biofilm formation, and whether allicin could potentiate the bactericidal effect of vancomycin in a rabbit PJI model.

Methods

A sterile stainless-steel screw with a sterile ultra-high molecular weight polyethylene washer was inserted into the lateral femoral condyle of the right hind knee joint of rabbit, and 1 mL inoculum containing 10⁴ colony-forming units of Staphylococcus epidermidis was inoculated into the knee joint (n = 32). Fourteen days later, rabbits randomly received one of the following 4 treatments using continuous lavages: normal saline, vancomycin (20 mcg/mL), allicin (4 mg/L), or allicin (4 mg/L) plus vancomycin (20 mcg/mL). Three days later, the washer surface biofilm formation was examined by scanning electron microscopy (SEM). The bacterial counts within the biofilm of implanted screws were determined by bacterial culture.

Results

The lowest number of viable bacterial counts of Staphylococcus epidermidis recovered from the biofilm was in the rabbits treated with allicin plus vancomycin (P<0.01 vs. all other groups). The biofilm formation was significantly reduced or undetectable by SEM in rabbits receiving allicin or allicin plus vancomycin.

Conclusion

Intra-articular allicincan inhibit biofilm formation and enhance the bactericidal effect of vancomycin on implant surface in vivo. Allicin in combination with vancomycin may be a useful anti-infection strategy for the treatment of PJI.     

Improving Immobilization of Pb(II) Ions by Aspergillus niger Cooperated with Photoelectron by Anatase Under Visible Light Irradiation

Lead pollution is rapidly becoming a serious concern, and remediation of lead contamination is a major challenge. Biological remediation is both environmentally friendly and sustainable process. In this study, we investigated the application of Aspergillus niger (Bpb1) for removing lead ion from a liquid medium by using photoelectron generated from a light-semiconductor mineral-microbial system. Synthetic anatase electrodes were systematically characterized and used as a photoelectron provider. Under light irradiation, the adsorption rates of Pb(II) by A. niger in the experimental groups increased by 204% (the maximum) on the fourth day, while the total adsorption rates remained the same. Further study of lead products revealed that lead ion combines with organic acids to form extracellular lead-containing products, which wrap around the fungal hyphae and combine with the cell wall. The anatase photoelectron enhanced the adsorption rate of Pb(II) by A. niger by forming larger lead-containing products, and by accelerating the transportation of Pb(II) into the inner cell. This novel approach provides newer insights into the application of biological degradation for environmental remediation.     

A Femtosecond Visible/Visible and Visible/Mid-Infrared Transient Absorption Study of the Light Harvesting Complex II

Light harvesting complex II (LHCII) is the most abundant protein in the thylakoid membrane of higher plants and green algae. LHCII acts to collect solar radiation, transferring this energy mainly toward photosystem II, with a smaller amount going to photosystem I; it is then converted into a chemical, storable form. We performed time-resolved femtosecond visible pump/mid-infrared probe and visible pump/visible probe absorption difference spectroscopy on purified LHCII to gain insight into the energy transfer in this complex occurring in the femto-picosecond time regime. We find that information derived from mid-infrared spectra, together with structural and modeling information, provides a unique visualization of the flow of energy via the bottleneck pigment chlorophyll a604.     

MyD88在抗衣原体感染的病理损伤过程中的作用

<正>沙眼衣原体(Chlamydia trachomatis,Ct)是引起泌尿生殖道感染的常见性病病原体之一,并可导致不孕、异位妊娠、宫颈鳞状细胞癌等并发症[1]。但有关沙眼衣原体确切的致病机制及机体的抗感染机制目前尚不清     

Light Inhibits Flagellation in a Chlamydomonas Mutant

We have isolated a new flagellar mutant in Chlamydomonas reinhardtii.When the mutant was cultured under the white fluorescent lamp({small tilde}4,800 lux), most cells had no flagella. However,when the cultures were put in the dark, flagellation occurred.Greater than 70% of the cells had flagella within 12–16h after the transfer. The flagellar morphology varied from "rod-shape"(same as the wild-type flagella) to "disk-shape". The disk-shapedflagella had the axonemes which were curved into a loop withinthe swollen membrane. Hence, this mutant is called loop-1. Light-inhibitionof flagellation was restored in the presence of 10^–5 MDCMU. The spectral dependency of the photo-inhibition of flagellation,determined using the Okazaki Large Spectrograph, showed maximaleffectiveness at 400–420 nm and 600–680 nm. Theseresults suggest that photosynthesis inhibits flagellation ofloop-1 cells. (Received July 27, 1989; Accepted January 29, 1990)     

Blue Light Inhibits Mitosis in Tissue Culture Cells

Irradiation of the mitotic (prophase and prometaphase) tissue culture PK (pig kidney embryo) cells using mercury arc lamp and band-pass filters postponed or inhibited anaphase onset. The biological responses observed after irradiation were: (i) normal cell division, (ii) delay in metaphase and then normal anaphase and incomplete cytokinesis, (iii) exit into interphase without separation of chromosomes, (iv) complete mitotic blockage. Cell sensitivity to the light at wavelengths from 423 and 488 nm was nearly the same; to the near UV light (wavelength 360 nm) it was 5–10 times more; to the green light (wavelength >500 nm) it was at least 10 times less. To elucidate the possible mechanism of the action of blue light we measured cell adsorption and examined cell autofluorescence. Autofluorescence of cytoplasmic granules was exited at wavelengths of 450–490 nm, but not at >500 nm. In mitotic cells fluorescent granules accumulated around the spindle. We suppose blue light irradiation induces formation of the free radicals and/or peroxide, and thus perturb the checkpoint system responsible for anaphase onset.     

A p7 Ion Channel-derived Peptide Inhibits Hepatitis C Virus Infection in Vitro

Viral infection is an early stage of its life cycle and represents a promising target for antiviral drug development. Here we designed and characterized three peptide inhibitors of hepatitis C virus (HCV) infection based on the structural features of the membrane-associated p7 polypeptide of HCV. The three peptides exhibited low toxicity and high stability while potently inhibiting initial HCV infection and suppressed established HCV infection at non-cytotoxic concentrations in vitro. The most efficient peptide (designated H2-3), which is derived from the H2 helical region of HCV p7 ion channel, inhibited HCV infection by inactivating both intracellular and extracellular viral particles. The H2-3 peptide inactivated free HCV with an EC₅₀ (50% effective concentration) of 82.11 nm, which is >1000-fold lower than the CC₅₀ (50% cytotoxic concentration) of Huh7.5.1 cells. H2-3 peptide also bound to cell membrane and protected host cells from viral infection. The peptide H2-3 did not alter the normal electrophysiological profile of the p7 ion channel or block viral release from Huh7.5.1 cells. Our work highlights a new anti-viral peptide design strategy based on ion channel, giving the possibility that ion channels are potential resources to generate antiviral peptides.     

Irradiation of Escherichia coli in the Visible Spectrum with a Tunable Organic-Dye Laser Energy Source

Pulsed laser energy was shown to be effective in inhibiting the growth of Escherichia coli. The irradiation source was derived from a tunable organic-dye laser utilizing rhodamine 6G (590 ± 5 nm) solutions as lasing media. The organisms, suspended in nutrient broth, were irradiated both with and without an exogenous photosensitizer. One photosensitizer (toluidine blue) did not appreciably alter the inhibitory effect observed. In the presence of acridine orange, however, some additional growth occurred.     

针刺联合红外线照射治疗腰椎间盘突出症的随机对照研究

目的：评价针刺联合红外线照射治疗腰椎间盘突出症的临床疗效。方法：选择2010 年9 月～2012 年1 月我院收治的90 例 腰椎间盘突出症患者为研究对象,并将其随机分为对照组和治疗组,每组45 例。对照组患者给予药物治疗,而治疗组患者给予针 刺联合红外线照射治疗,治疗后评价和比较两组患者的临床疗效及腰腿痛的改善情况。结果：针刺联合红外线照射治疗腰椎间盘 突出症显效率为62.2%,药物组显效率为26.7%,两组有显著性差异(Ｐ<0.05)。治疗后,治疗组患者腰腿痛疼痛评分明显低于对照 组,差异有统计学意义(P<0.01)。结论：以针刺联合红外线照射治疗腰椎间盘突出症的临床疗效肯定,值得临床推广。     

Acute Toxicity of TiO2 Nanoparticles to Ceriodaphnia dubia under Visible Light and Dark Conditions in a Freshwater System

The ever increasing industrial and consumer applications of titanium dioxide nanoparticles (TiO₂ NPs) raise concern over the possible risk associated with their environmental exposure. Still, the knowledge regarding nanoparticle behavior in a freshwater ecosystem is lacking. The current study focuses on the toxicity of TiO₂ NPs towards Ceriodaphnia dubia (a dominant daphnid isolated from the freshwater) under two different conditions; (1) light and dark photoperiod (16:8 h) and (2) continuous dark conditions, for a period of 48 h. An increase in toxicity was observed with an increase in the concentration, until a certain threshold level (under both photoperiod and dark conditions), and beyond which, reduction was noted. The decrease in toxicity would have resulted from the aggregation and settling of NPs, making them less bioavailable. The oxidative stress was one of the major contributors towards cytotoxicity under both photoperiod and dark conditions. The slow depuration of TiO₂ NPs under the photoperiod conditions confirmed a higher NP bioaccumulation and thus a higher bioconcentration factor (BCF) compared to dark conditions. The transmission electron micrographs confirmed the bioaccumulation of NPs and damage of tissues in the gut lining.     

A Metamaterial Absorber Operating in the Visible Light Band Based on a Cascade Structure

Plasmonics - In this paper, a broadband and polarization-insensitive metamaterial absorber (MA) operating in the visible light band based on a cascade structure is proposed, and the main structure...     

Somnolence after Prophylactic Cranial Irradiation in Children with Acute Lymphoblastic Leukaemia

A transient cerebral disturbance characterized by somnolence of varying degree is described in children after cranial irradiation given as part of central nervous system (C.N.S.) prophylaxis for acute lymphoblastic leukaemia in remission.Out of 28 such children receiving cranial irradiation as part of the Medical Research Council protocol for C.N.S. prophylaxis 11 (39%) developed pronounced symptoms of somnolence, anorexia, and lethargy some six weeks after the completion of cranial irradiation, and a further 11 (39%) developed these features in mild form. In all cases the symptoms were transient, no focal neurological abnormality was detected, and all children made a spontaneous and complete recovery. E.E.G. studies on five somnolent children showed similar abnormal activity of diffuse and patchy distribution over both hemispheres. Indirect evidence is presented to support the concept that this syndrome represents a transient radiation encephalopathy, analogous to acute transient radiation myelopathy, caused by temporary disturbance of myelin synthesis.