Complement-pentraxins synergy: Navigating the immune battlefield and beyond

The complement is a crucial immune defense system that triggers rapid immune responses and offers efficient protection against foreign invaders and unwanted host elements, acting as a sentinel. Activation of the complement system occurs upon the recognition of pathogenic microorganisms or altered self-cells by pattern-recognition molecules (PRMs) such as C1q, collectins, ficolins, and pentraxins. Recent accumulating evidence shows that pentraxins establish a cooperative network with different classes of effector PRMs, resulting in synergistic effects in complement activation. This review describes the complex interaction of pentraxins with the complement system and the implications of this cooperative network for effective host defense during pathogen invasion.

[Research progress of non-biological artificial liver support system therapy for paitents with liver failure]

Liver failure progresses quickly with high mortality. Non-biological artificial liver support system therapy is one of the important treatments for patients with liver failure. The basic techniques of non-biological artificial liver support system therapy include plasma exchange, plasma adsorption and continuous renal replacement therapy. In this paper, the effect and choice of these basic techniques, the treatment timing, the possible patients who may benefit, and the existing problems are summarized and discussed. We hope to provide a reference for the rational use of non-biological artificial liver support system therapy in clinical practice.

[Application of ultra-short echo time-T2* component analysis technology in monitoring morphological and biochemical changes of achilles tendon in amateur marathon athletes]

Objective: To explore the value of ultra-short echo time (UTE)-T₂* component analysis techniques in dynamic monitoring the morphological and biochemical changes in amateur marathon athletes' achilles tendon before and after the marathon. Methods: Twenty-nine amateur marathon runners were recruited between October 2020 and March 2021 in Zhuhai City, Guangdong Province, including 25 males and 4 females, aged from 24 to 50 (40±6) years old. All volunteers underwent bilateral achilles tendon MRI examination 1 week before the marathon, 48 hours after the race, and 1 month after the race. The shape and signal of the achilles tendon were evaluated by routine T1-weighted, proton density weighted with fat saturation sequence and different echo time (TE) UTE sequence, and the changes of achilles tendon after running was quantitatively analyzed by UTE-T2* sequence. The values of single-component analysis (T₂*_M), short T₂* components (T₂*_S), and long T₂* components (T₂*_L) and Fraction values were obtained using UTE-T₂* sequence. The value of the whole achilles tendon was measured on the sagittal images of achilles tendon, and the Achilles tendon was equally divided into three subregions [muscle-tendon junction (MTJ), middle (MID), and insertion (INS)]. The region of interest was delineated by two radiologists independently. The intra-group correlation coefficient (ICC) was used to evaluate the consistency of the data measured by two radiologists. Nonparametric Friedman M test was used to compare the differences of T₂*_M, T₂*_S, T₂*_L and Fraction values in different time points and different subregions. Wilcoxon rank-sum test was used to compare the difference between 48 h post-race and pre-race T₂*_S values (ΔT₂*_S) of different distance, different running posture, different pace and different amount of training, in which ΔT₂*_S equals the T₂*_S value of 48 h post-race minus the T₂*_S value of pre-race. Results: On the sequence of short TE (TE≤0.6 ms), achilles tendinopathy can manifest as scattered punctate hypointensity in areas of high signal intensity. The two radiologists showed a good consistency in measuring the T₂*_M, T₂*_S, T₂*_L and Fraction values of the achilles tendon, and the ICC values ​​were 0.96, 0.94, 0.83 and 0.94, respectively. The T₂*s values was significantly higher in the whole Achilles tendon, MTJ and MID segment at 48 h post-exercise compared to pre-exercise, and decreased after 1 month of exercise, [0.49 (0.45, 0.59) vs 0.54 (0.49, 0.59) vs 0.53 (0.49, 0.57), 0.48 (0.44, 0.54) vs 0.53 (0.47, 0.58) vs 0.50 (0.46, 0.57), 0.48 (0.43, 0.58) vs 0.54 (0.47, 0.59) vs 0.52 (0.46, 0.57); respectively, all P<0.05]. The changes in T₂*_M, T₂*_L and Fraction values are not statistically significant (all P>0.05). In different running gestures, the ΔT₂*_S of achilles tendon who using the postures of front-middle feet is higher than that using the postures of back feet (0.03(-0.05, 0.07) vs -0.03(-0.17, 0.11), P=0.001). Conclusion: The Bi-component analysis of UTE-T₂* technology is superior to single component analysis in monitoring the dynamic changes of achilles tendon before and after exercise, and T₂*_S is a more sensitive sequence to evaluate the subtle changes in the chemical composition of achilles tendon.

Artesunate: A natural product-based immunomodulator involved in human complement

Complement is an important innate immune defence machinery. Once dysregulated, it is often linked to pathogenesis of diverse autoimmune diseases. Artesunate (ART) is a well-known anti-malarial compound. Recently, ART has been highlighted by its potential therapeutic effects on certain complement-related autoimmune diseases. However, the underlying mechanisms are hitherto unknown. In the present study, we found that ART mediated complement interception as validated by analysis of complement haemolytic assay. In cell-based setup using dying Jurkat cells, ART-mediated complement interception was also confirmed. Further, we newly established an ELISA system selectively allowing complement activation via the classical pathway, the lectin pathway and the alternative pathway, respectively. ELISA analysis revealed that ART dose-dependently inhibited C4 activation, C3 activation and terminal complement complex assembly via the effector pathways. ART was found to blockade C1q, C3 and C5 with a lesser extent to properdin. The interaction of ART with C1q was determined to be mediated via C1q globular head region. FACS analysis using ART-conjugated mesoporous silica particles revealed that ART specifically bound the key therapeutic targets of C1q, C3 and C5 on microparticles. In conclusion, we for the first time report the anti-complement bioactivities of ART and suggest a potential therapeutic benefit of ART in the complement-related human diseases.

Soluble collectin-12 mediates C3-independent docking of properdin that activates the alternative pathway of complement

Properdin stabilizes the alternative C3 convertase (C3bBb), whereas its role as pattern-recognition molecule mediating complement activation is disputed for decades. Previously, we have found that soluble collectin-12 (sCL-12) synergizes complement alternative pathway (AP) activation. However, whether this observation is C3 dependent is unknown. By application of the C3-inhibitor Cp40, we found that properdin in normal human serum bound to Aspergillus fumigatus solely in a C3b-dependent manner. Cp40 also prevented properdin binding when properdin-depleted serum reconstituted with purified properdin was applied, in analogy with the findings achieved by C3-depleted serum. However, when opsonized with sCL-12, properdin bound in a C3-independent manner exclusively via its tetrameric structure and directed in situ C3bBb assembly. In conclusion, a prerequisite for properdin binding and in situ C3bBb assembly was the initial docking of sCL-12. This implies a new important function of properdin in host defense bridging pattern recognition and specific AP activation.

[Research progress of the application of regional citrate anticoagulation in artificial liver to treat liver failure]

Liver failure is a rapidly progressive condition with a high mortality rate. Artificial liver treatment is one of the most important treatments for liver failure. In order to ensure the smooth functioning of in vitro circulation device, anticoagulants such as heparin or low-molecular-weight heparin are often used in clinical practice. However, it induces hemorrhage, thrombocytopenia and other adverse reactions, thereby threatening the life safety of liver failure patients. Regional citrate anticoagulation does not affect the coagulation mechanism in vivo, nor does it effects platelets, so in vitro circulating anticoagulants has become the first choice anticoagulant treatment method for continuous renal replacement therapy. Combined with the current research condition at home and abroad, the research progress of the application of regional citrate anticoagulation in artificial liver to treat liver failure is discussed, covering its principle content, application status and application prospect.

Two new phenolic glycosides with anti-complementary activity from the roots of Sanguisorba officinalis L

Sanguisorba officinalis L. is a traditional herbal plant that belongs to the genus Sanguisorba and the family Rosaceae. Two new phenolic glycosides (1-2), ten known phenolics (3-12), and six known monoterpenoid glycosides (13-18) were isolated from the roots of S. officinalis using silica gel column and preparative middle pressure liquid chromatography (MPLC). The chemical structures were elucidated based on extensive spectroscopic experiments, including 1D and 2D NMR as well as HR-ESI-MS, and comparison with those reported in the literature. Compounds 3-5, and 13 were isolated from the Rosaceae family and compound 7 was obtained from the genus Sanguisorba for the first time. Additionally, all compounds were evaluated for their anti-complementary activities against the classical pathway. Furthermore, compounds 1, 5, 9, and 14 showed significant anti-complementary activities with the 50% haemolytic inhibition concentrations (CH₅₀) values of 0.40 ± 0.03, 0.57 ± 0.01, 0.51 ± 0.07, and 0.53 ± 0.05 mM, respectively.

[Clinical application effect of blood circulation enhancement technique in repairing large area of skin and soft tissue defects of extremities with super large free anterolateral thigh flap]

Objective: To observe the clinical application effect of blood circulation enhancement technique in repairing large area of skin and soft tissue defects of extremities with super large free anterolateral thigh flap. Methods: From March 2014 to March 2017, 6 patients with large area of skin and soft tissue defects of extremities were hospitalized in our unit, including 5 males and 1 female, aged 27-65 years, 1 case of electric injury, 2 cases of coal burn, 3 cases of traffic injury, 2 cases involving upper limb, and 4 cases involving lower limb. After debridement, the wound area ranged from 26 cm×8 cm to 36 cm×15 cm, and the bone exposure area ranged from 24 cm×7 cm to 35 cm×14 cm. The blood circulation enhancement technique was used when the wound with bone exposure was repaired with super large free anterolateral thigh flap. The area of flaps ranged from 28 cm×10 cm to 38 cm×16 cm. The donor site of flap and the primary wound without bone exposure were repaired with medial thigh split-thickness skin graft of the donor leg of flap. The blood circulation enhancement technique mode during operation and the survival of flaps after operation were recorded, and the recovery of donor and recipient areas and the occurrence of complications were followed up. Results: Three patients were treated with simple vascular supercharging technique during flap transplantation, and the other 3 patients were treated with vascular supercharging and turbocharging technique during flap transplantation. All the flaps survived well in 6 patients without vascular crisis. Follow-up for 3 to 12 months after surgery showed that the blood flow of the flaps was good and the depth and superficial sensation recovered to varying degrees. Except for 1 case of upper limb flap, the other flaps had no obvious swelling and needed no second thinning. There were only depressed scars in the donor sites, and no obvious scar hyperplasia in the area without bone exposure repaired by the skin grafts. No short-term or long-term complications were found. Conclusions: The application of blood circulation enhancement technique in repairing large area of skin and soft tissue defects of extremities with super large free anterolateral thigh flaps provides reliable blood supply for the flaps and results in good effect after operation, which is worth popularizing.

Ultrastrong and Stiff Carbon Nanotube/Aluminum-Copper Nanocomposite via Enhancing Friction between Carbon Nanotubes

Researchers have been aiming to replace copper with carbon nanotube/copper nanocomposites, which are lighter and exhibit better electrical, mechanical, and thermal properties. However, the strength is far below pure carbon nanotube assembly and even much lower than some copper-based alloys. This disadvantage hinders the extensive application of carbon nanotube/copper nanocomposites. In this study, the carbon nanotube/aluminum-copper nanocomposites with ultra-strength and stiffness were prepared. The strength and elasticity modulus of composite reached as high as 6.6 and 500 GPa, respectively, while a high conductivity of 1.8 × 10⁷ S/m was maintained. This can be attributed to the diffusion of Cu and Al atoms into the carbon nanotube fiber, which enhances friction between the carbon nanotubes by "pinning" and "bridging". This structure provides us with novel insights into the design of carbon nanotubes/metal nanocomposites with ultrahigh strength and conductivity.

[Relationship of TLR2 and TLR4 expressions on the surface of peripheral blood mononuclear cells to small intestinal bacteria overgrowth in patients with hepatocellular carcinoma]

Objective: To investigate TLR2 and TLR4 expressional situation on the surface of peripheral blood mononuclear cells (PBMC) in patients with hepatocellular carcinoma (HCC) and their relationship with small intestinal bacterial overgrowth (SIBO). Methods: Flow cytometry was used to detect TLR2 and TLR4 expressional situation on the surface of PBMC in 78 cases with HCC, 56 cases with cirrhosis and 33 healthy controls. Furthermore, lactose hydrogen breath test (LHBT) was used to detect small intestinal bacterial overgrowth. Results: Of the 78 cases with HCC, 56 cases (71.8%) were SIBO-positive, 23 cases (41.1%) were SIBO- positive in 56 cases with cirrhosis, and 1 (3.0%) was SIBO-positive in 33 healthy controls. The incidence of SIBO in HCC patients was higher than cirrhosis patients (χ(2) = 12.72, P < 0.05) and healthy controls (χ(2) = 41.18, P < 0.05). The expression levels of TLR2 and TLR4 in HCC patients (100.55 ± 24.22, 42.76 ± 15.96) were significantly higher than cirrhosis (67.42 ± 18.36, 24.38 ± 8.68)and healthy control group (33.06 ± 11.72, 12.52 ± 4.46) (P < 0.05). Furthermore, the expression levels of TLR2 and TLR4 in SIBO-positive patients (108.75 ± 20.40, 48.1 ± 14.98) were higher than SIBO-negative patients (79.67 ± 20.60, 28.62 ± 7.36) (P < 0.05). Conclusion: The expression of TLR2 and TLR4 and the incidence of SIBO in HCC patients are significantly higher than cirrhosis and healthy control group. Moreover, the high expressions of TLR2 and TLR4 in SIBO-positive HCC patients may promote the development of HCC.

[miRNA-96-5p inhibits the proliferation and migration of gastric cancer cells by targeting FoxQ1]

Objective: To investigate the role of microRNA-96-5p in the proliferation and invasion of gastric cancer cells and its molecular mechanism. Methods: From June 2015 to January 2017, 53 resected specimens were collected. The transcriptional levels of microRNA-96-5p and forkhead box Q1 (FoxQ1) in gastric cancer tissues and the matched para-cancerous tissues were quantified by quantitative real-time PCR (qRT-PCR). The expression of FoxQ1 protein was also detected by immunohistochemistry (IHC). The relationship between microRNA-96-5p expression and the clinicopathological features of gastric cancer and its correlation with FoxQ1 expression were analyzed. The expressions of miRNA-96-5p in gastric cancer tissue and adjacent normal tissue were detected by qRT-PCR. miRNA-96-5p mimics was transfected to BGC-823 gastric cancer cells. The effects of miRNA-96-5p on cell proliferation and invasion were detected by cell counting kit-8 (CCK-8) assay and Transwell assay, respectively. The protein expressions of FoxQ1, E-cadherin and vimentin were determined by western blot. The relationship between FoxQ1 and miRNA-96-5p expressed in BGC-823 cells was detected by dual-luciferase reporter assay. Results: The median expression of miRNA-96-5p in gastric cancer tissue was 1.05, significantly lower than 3.23 of para-cancerous tissues (P<0.05). The positive rate of FoxQ1 expression in gastric cancer tissue was 71.7%, significantly higher than 28.3% of para-cancerous tissues (P<0.05). The expression of FoxQ1 was negatively corelated with the level of miRNA-96-5p (r=-0.613, P=0.006). The expression of miRNA-96-5p in gastric cancer cell BGC-823 was significantly decreased compared with normal gastric epithelial cell (0.96±0.08 vs 2.84±0.15, P<0.05). The results of CCK-8 assay and Transwell assay showed that overexpression of miRNA-96-5p significantly reduced the proliferation and invasion abilities of gastric cancer cells (P<0.05). Overexpression of miRNA-96-5p decreased the protein level of FoxQ1. Moreover, it upregulated the expression of E-cadherin and downregulated the expression of vimentin. The result of dual-luciferase-3'-UTR reporter assay confirmed that miRNA-96-5p binds to the 3'UTR of FoxQ1. Conclusion: miRNA-96-5p may suppress the proliferation, migration and epithelial-mesenchymal transition (EMT) of gastric cancer cell by down-regulation of FoxQ1.

[Cogan syndrome with audiovestibular disfunction: 2 cases report]

We describe a case of Cogan syndrome in patients with clinical manifestations, related examinations and diagnosis,treatment,and review of relevant literature. Both patients had bilateral moderate to severe sensorineural hearing loss. The collateral function test showed that there were bilateral semicircular canal paresis,and the head impulse test had a bilateral gain value between 0.09 and 0.55. It showed obvious compensatory saccade wave, the head impulse suppression test bilateral no anti-compensation saccade wave.Cogan syndrome is a rare syndrome with unspecific symptoms and early diagnosis is difficult. However, the involvement of the auditory vestibular systems are often poor prognosis and needs to be diagnosed by early diagnosis and treatment.

[Research advances in chronicity of hepatitis E virus infection]

Hepatitis E virus (HEV) infection usually causes acute hepatitis and has a self-limiting progression. The patients often recover within 6 months with good prognosis. Recent studies have found that HEV infection may become chronic in special situations, which manifests as persistent liver function abnormalities for at least 6 months after acute HEV infection and the presence of viral nucleic acid in serum, feces, and/or liver tissue. Chronicity of HEV infection mainly occurs in immunocompromised patients, and it is rare but very dangerous in clinical practice. An understanding of the pathogenesis, clinical manifestations, treatment methods, and preventive measures of chronicity of HEV infection helps clinical physicians develop an effective management regimen and improve patient prognosis. This article introduces related issues, in order to raise the awareness of this disease among clinical physicians.

[Clinical effects of perforating branch flaps of medial vastus muscle in repairing secondary wounds in donor sites of free anterolateral femoral perforator flaps]

Objective: To investigate the clinical effects of perforating branch flaps of medial vastus muscle in repairing secondary wounds in donor sites of free anterolateral femoral perforator flaps. Methods: From August 2014 to December 2016, 12 patients (8 males and 4 females, aged 35-72 years) with skin and soft tissue defects of extremities associated with tendon and bone exposure were treated in Hanzhong Central Hospital. The sizes of the primary wounds after debridement were 10 cm×8 cm-22 cm×14 cm, and the wounds were repaired with 12 cm×10 cm-24 cm×16 cm free anterolateral femoral perforator flaps. The anterolateral femoral donor sites, which were 8.0 cm×4.0 cm-14.0 cm×7.5 cm in the secondary wounds after skin extensional suture, were repaired with perforating branch flaps of medial vastus muscle in the size of 9.0 cm×5.0 cm-15.0 cm×8.5 cm. The medial femoral donor sites were sutured directly. Results: All the perforating branch flaps of medial vastus muscle and free anterolateral femoral perforator flaps survived in 12 patients. Following up for 6 to 12 months, the medial femoral perforator flaps had good local shape and texture. The flaps of 8 patients without cutaneous nerve transection were sensitive. The sensation of the flaps of the other 4 patients gradually recovered, and the functions of the ipsilateral knee joints were normal. Conclusions: The medial femoral perforator flap has a stable anatomy and abundant blood supply, which can be used to repair the secondary wound in the donor site of the free anterolateral femoral perforator flap conveniently. It is safe and easy to be popularized. Moreover, it has a good shape and function after operation.

Pentraxins in Complement Activation and Regulation

The complement is the first line of immune defense system involved in elimination of invading pathogens and dying host cells. Its activation is mainly triggered by immune complexes or pattern recognition molecules (PRMs) upon recognition against non-self or altered self-cells, such as C1q, collectins, ficolins, and properdin. Recent findings have interestingly shown that the pentraxins (C-reactive protein, CRP; serum-amyloid P component, SAP; long pentraxin 3, PTX3) are involved in complement activation and amplification via communication with complement initiation PRMs, but also complement regulation via recruitment of complement regulators, for instance C4b binding protein (C4BP) and factor H (fH). This review addresses the potential roles of the pentraxins in the complement system during infection and inflammation, and emphasizes the underlining implications of the pentraxins in the context of complement activation and regulation both under physiological and pathological conditions.

Apoptosis of hepatocarcinoma cells Hepg2 induced by Huaier extract through regulation of HBx and CEACAM1 gene expression

Huaier can effectively inhibit the growth of tumor cells by enhancing the immune system. However, the mechanism of its function is still not clear. The current study aimed to explore the possible mechanism of Huaier in inhibiting human hepatocarcinoma cells by observing its effect on proliferation and invasion in hepatocarcinoma cells, HepG2 and HepG2-X, which stably express the HBx gene, and by comparing the levels of mRNA transcription and protein expression of HBx and CEACAM1 in HepG2 cells and HepG2-X cells when treated with different concentrations of Huaier. HepG2 cells and HepG2-X cells were treated with 0, 1.5, 3.0, and 6.0 g/L-1 Huaier extract in vitro. MTT assay was used to measure the inhibition of cell proliferation. The transwell cell model coated with Matrigel glue was used to detect the invasion of HepG2 and HepG2-X cells in vitro. Flowcytometry was used to observe changes in cell cycle. Real-time PCR and Western blot were used to detect HBx and CEREAM1 mRNA transcription and protein expression separately. Huaier extract can inhibit HepG2 and HepG2-X cell proliferation in a time- and dose-dependent manner. The A value of HepG2-X cells in each group was higher than that of HepG2 cells. Compared with the control group, the invasion ability of HepG2 and HepG2-X cells decreased significantly after treatment with Huaier extract, in a dose-dependent manner. The cell cycle of HepG2 and HepG2-X was arrested at S phase. The distribution of G0/G1 phase decreased gradually with the increase of the concentration of Huaier extract, and the proportion of G0/G1 phase distribution declined. After treating with Huaier extract, mRNA transcription and protein expression of HBx in HepG2 and HepG2-X declined, while those of CEACAM1 increased, reflecting a dose-dependent manner (P less than 0.05). Therefore, we concluded that the inhibitory effect of Huaier extract on hepatocarcinoma cell proliferation might function through down regulation of HBx gene expression and upregulation of CEACAM1 gene expression.

Determination of atomic-scale chemical composition at semiconductor heteroepitaxial interfaces by high-resolution transmission electron microscopy

The determination of atomic structures and further quantitative information such as chemical compositions at atomic scale for semiconductor defects or heteroepitaxial interfaces can provide direct evidence to understand their formation, modification, and/or effects on the properties of semiconductor films. The commonly used method, high-resolution transmission electron microscopy (HRTEM), suffers from difficulty in acquiring images that correctly show the crystal structure at atomic resolution, because of the limitation in microscope resolution or deviation from the Scherzer-defocus conditions. In this study, an image processing method, image deconvolution, was used to achieve atomic-resolution (∼1.0 Å) structure images of small lattice-mismatch (∼1.0%) AlN/6H-SiC (0001) and large lattice-mismatch (∼8.5%) AlSb/GaAs (001) heteroepitaxial interfaces using simulated HRTEM images of a conventional 300-kV field-emission-gun transmission electron microscope under non-Scherzer-defocus conditions. Then, atomic-scale chemical compositions at the interface were determined for the atomic intermixing and Lomer dislocation with an atomic step by analyzing the deconvoluted image contrast. Furthermore, the effect of dynamical scattering on contrast analysis was also evaluated for differently weighted atomic columns in the compositions.

InP-based pseudomorphic InAs/InGaAs triangular quantum well lasers with bismuth surfactant

An InP-based 2.1 μm InAs/In_0.53Ga_0.47As triangular quantum well laser grown with Bi surfactant has shown improved performance in comparison to the device with the same structure but grown without Bi surfactant. Under continuous-wave driving operation, the output light power is increased from 32.6 to 37.5 mW at the same injecting current of 850 mA at 200 K. The external differential and internal quantum efficiencies for the laser with Bi surfactant are 18.4% and 41%, respectively, which are correspondingly higher than 13.1% and 31% for the reference device. Furthermore, a decreased internal loss from 20.9 to 17.6  cm^-1 for the Bi surfactant laser is also observed. These results suggest that Bi surfactant is promising for further enhancing performances of strained quantum well laser diodes.

An overview of the synergy and crosstalk between pentraxins and collectins/ficolins: their functional relevance in complement activation

The complement system is an innate immune defense machinery comprising components that deploy rapid immune responses and provide efficient protection against foreign invaders and unwanted host elements. The complement system is activated upon recognition of pathogenic microorganisms or altered self-cells by exclusive pattern recognition molecules (PRMs), such as collectins, ficolins and pentraxins. Recent accumulating evidence shows that the different classes of effector PRMs build up a co-operative network and exert synergistic effects on complement activation. In this review, we describe our updated view of the crosstalk between previously unlinked PRMs in complement activation and the potential pathogenic effects during infection and inflammation.

A journey through the lectin pathway of complement-MBL and beyond

Mannose-binding lectin (MBL), collectin-10, collectin-11, and the ficolins (ficolin-1, ficolin-2, and ficolin-3) are soluble pattern recognition molecules in the lectin complement pathway. These proteins act as mediators of host defense and participate in maintenance of tissue homeostasis. They bind to conserved pathogen-specific structures and altered self-antigens and form complexes with the pentraxins to modulate innate immune functions. All molecules exhibit distinct expression in different tissue compartments, but all are found to a varying degree in the circulation. A common feature of these molecules is their ability to interact with a set of serine proteases named MASPs (MASP-1, MASP-2, and MASP-3). MASP-1 and -2 trigger the activation of the lectin pathway and MASP-3 may be involved in the activation of the alternative pathway of complement. Furthermore, MASPs mediate processes related to coagulation, bradykinin release, and endothelial and platelet activation. Variant alleles affecting expression and structure of the proteins have been associated with a variety of infectious and non-infectious diseases, most commonly as disease modifiers. Notably, the severe 3MC (Malpuech, Michels, Mingarelli, and Carnevale) embryonic development syndrome originates from rare mutations affecting either collectin-11 or MASP-3, indicating a broader functionality of the complement system than previously anticipated. This review summarizes the characteristics of the molecules in the lectin pathway.

MAVEN observations of the response of Mars to an interplanetary coronal mass ejection

Coupling between the lower and upper atmosphere, combined with loss of gas from the upper atmosphere to space, likely contributed to the thin, cold, dry atmosphere of modern Mars. To help understand ongoing ion loss to space, the Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft made comprehensive measurements of the Mars upper atmosphere, ionosphere, and interactions with the Sun and solar wind during an interplanetary coronal mass ejection impact in March 2015. Responses include changes in the bow shock and magnetosheath, formation of widespread diffuse aurora, and enhancement of pick-up ions. Observations and models both show an enhancement in escape rate of ions to space during the event. Ion loss during solar events early in Mars history may have been a major contributor to the long-term evolution of the Mars atmosphere.

Investigating the Composition and Conductance Distributions on Highly GeSi Mixed Quantum Dots and Inside Oxidation Problem

With the help of a nanoscale trench, the composition and conductance distributions of single GeSi quantum dots (QDs) are obtained by conductive atomic force microscopy combined with selective chemical etching. However, the obtained composition and current distributions are unwonted and inconsistent on the QDs grown at 680 °C. With a series of confirmatory experiments, it is suggested that a thick oxide layer is formed and remains on the QDs' surface after etching. Though this selective chemical etching has already been widely applied to investigate the composition distribution of GeSi nanostructures, the oxidation problem has not been concerned yet. Our results indicate that the oxidation problem could not be ignored on highly GeSi mixed QDs. After removing the oxide layer, the composition and conductance distributions as well as their correlation are obtained. The results suggest that QDs' current distribution is mainly determined by the topographic shape, while the absolute current values are influenced by the Ge/Si contents.

Pentraxin-3 level at admission is a strong predictor of short-term mortality in a community-based hospital setting

BACKGROUND

The pattern recognition molecule pentraxin-3 (PTX3) is a novel potential marker of prognosis, as elevated levels are associated with both disease severity and mortality in patients with a wide range of conditions. However, the usefulness of PTX3 as a prognostic biomarker in a general hospital setting is unknown.

PATIENTS AND METHODS

The study cohort consisted of 1326 unselected, consecutive patients (age >40 years) admitted to a community hospital in Copenhagen, Denmark. Patients were followed until death or for a median of 11.5 years after admission. The main outcome measure was all-cause mortality. Serum samples collected from patients at admission and from 192 healthy control subjects were quantified for PTX3 level by enzyme-linked immunosorbent assay.

RESULTS

PTX3 was elevated in patients (median 3.7 ng mL(-1) , range 0.5-209.8) compared with healthy nonhospitalized subjects (median 3.5 ng mL(-1) , range 0.0-8.3; P = 0.0003). Elevated PTX3 levels, defined as above the 95th percentile of the concentration in healthy subjects, were associated with increased overall mortality during the study (P < 0.0001). This increase in mortality was greatest in the short term, with an unadjusted hazard ratio (HR) of 6.4 [95% confidence interval (CI) 3.8-11.0] at 28 days after admission, compared to 1.7 (95% CI 1.4-2.0) at the end of follow-up. These results were still significant after adjustment for age, gender and glomerular filtration rate: adjusted HR of 5.0 (95% CI 2.9-8.8) and 1.4 (95% CI 1.2-1.8), respectively.

CONCLUSION

These results suggest that PTX3 could be a widely applicable marker of short-term mortality in hospitalized patients and may be useful in the initial risk stratification.

The pattern recognition molecule ficolin-1 exhibits differential binding to lymphocyte subsets, providing a novel link between innate and adaptive immunity

Ficolin-1 is a soluble pattern recognition molecule synthesized by myeloid cells and capable of activating the lectin pathway of complement on the surface of pathogens. It is tethered to the membranes of monocytes and granulocytes; however, the biological significance of cell-associated ficolin-1 is unknown. Recognition of healthy host cells by a pattern recognition molecule constitutes a potential hazard to self cells and tissues, emphasizing the importance of further elucidating the reported self-recognition. In the current study we investigated the potential recognition of lymphocytes by ficolin-1 and demonstrated that CD56(dim) NK-cells and both CD4(+) and CD8(+) subsets of activated T-cells were recognized by ficolin-1. In contrast we did not detect binding of ficolin-1 to CD56(bright) NK-cells, NKT-cells, resting T-cells or B-cells. Furthermore, we showed that the protein-lymphocyte interaction occurred via the pathogen-recognition domain of ficolin-1 to sialic acid on the cell surface. Thus, the differential binding of ficolin-1 to lymphocyte subsets suggests ficolin-1 as a novel link between innate and adaptive immunity. Our results provide new insight about the recognition properties of ficolin-1 and point toward additional immune modulating functions of the molecule besides its role in pathogen recognition.

Experimental results of a dual-beam ion source for 200 keV ion implanter

A dual beam ion source for 200 keV ion implanter aimed to produce 200 keV H2 (+) and He(+) beams simultaneously has been developed. Not suitable to use the analyzing magnet, the purity of beam extracted from the source becomes important to the performance of implanter. The performance of ion source was measured. The results of experiments show that the materials of inlet tube of ion source, the time of arc ionization in ion source, and the amount of gas flow have significant influence on the purity of beam. The measures by using copper as inlet tube material, long time of arc ionization, and increasing the inlet of gas flow could effectively reduce the impurity of beam. And the method using the gas mass flow controller to adjust the proportion of H2 (+) and He(+) is feasible.

Pentraxin-3 serum levels are associated with disease severity and mortality in patients with systemic inflammatory response syndrome

The long pentraxin-3 (PTX3) is a key component of the humoral arm of the innate immune system. PTX3 is produced locally in response to pro-inflammatory stimuli. To investigate PTX3 levels and its use as a biomarker in patients with systemic inflammation, we developed a solid-phase enzyme-linked immunosorbent assay based on novel anti-PTX3 monoclonal antibodies detecting PTX3 with high sensitivity. The assay was applied on 261 consecutive patients admitted to an intensive care unit prospectively monitored with the systemic inflammatory response syndrome (SIRS). 100 blood donors were included as controls. PTX3 levels were elevated in patients (median = 71.3 ng/ml) compared with the controls (median = 0 ng/ml) (Mann-Whitney, p<0.0001). ROC analysis showed that PTX3 levels were significantly specific (85.0%) and sensitive (89.1%) to discriminate between healthy controls and patients (area under the curve (AUC) 0.922 (95% CI 0.892 to 0.946, p<0.0001)). Higher levels of PTX3 were associated with the development of sepsis, severe sepsis and septic shock (p = 0.0001). The serum levels of PTX3 correlated significantly with SAPS2 score (Spearman's rho 0.28, p<0.0001). Patients with high levels of PTX3 at admission did have a higher 90 day mortality rate than patients with the 25% lowest levels (Cox regression analysis, hazard ratio 3.0, p = 0.0009). In conclusion, we have established a highly sensitive and robust assay for measurement of PTX3 and found that its serum concentrations correlated with disease severity and mortality in patients with SIRS and sepsis.

Ficolin-1-PTX3 complex formation promotes clearance of altered self-cells and modulates IL-8 production

The long pentraxin 3 (PTX3) has been shown to be important in maintaining internal tissue homeostasis and in protecting against fungal Aspergillus fumigatus infection. However, the molecular mechanisms of how these functions are elicited are poorly delineated. Ficolin-1 is a soluble pattern recognition molecule that interacts with PTX3. We hypothesized that heterocomplexes between ficolin-1 and PTX3 might mediate the signals necessary for sequestration of altered self-cells and A. fumigatus. We were able to show that ficolin-1 interacts with PTX3 via its fibrinogen-like domain. The interaction was affected in a pH- and divalent cation-sensitive manner. The primary binding site for ficolin-1 on PTX3 was located in the N-terminal domain portion of PTX3. Ficolin-1 and PTX3 heterocomplex formation occurred on dying host cells, but not on A. fumigatus. The heterocomplex formation was a prerequisite for enhancement of phagocytosis by human monocyte-derived macrophages and downregulation of IL-8 production during phagocytosis. On A. fumigatus, PTX3 exposed the C-terminal portion of the molecule, probably resulting in steric hindrance of ficolin-1 interaction with PTX3. These results demonstrate that ficolin-1 and PTX3 heterocomplex formation acts as a noninflammatory "find me and eat me" signal to sequester altered-host cells. The fact that the ficolin-1-PTX3 complex formation did not occur on A. fumigatus shows that PTX3 uses different molecular effector mechanisms, depending on which domains it exposes during ligand interaction.

Mouse mannose-binding lectin-A and ficolin-A inhibit lipopolysaccharide-mediated pro-inflammatory responses on mast cells

It is unknown how soluble pattern-recognition receptors in blood, such as mannose-binding lectin (MBL) and ficolins, modulate mast cell-mediated inflammatory responses. We investigate how mouse MBL-A or ficolin-A regulate mouse bone marrow-derived mast cells (mBMMCs)-derived inflammatory response against bacterial lipopolysaccharide (LPS) stimulation. LPS-mediated pro-inflammatory cytokine productions on mBMMCs obtained from Toll-like receptor4 (TLR4)-deficient mice, TLR2-defficient mice, and their wildtype, were specifically attenuated by the addition of either mouse MBL-A or ficolin-A in a dose-dependent manner. However, the inhibitory effects by mouse MBL-A or ficolin-A were restored by the addition of mannose or N-acetylglucosamine, respectively. These results suggest that mouse MBL-A and ficolin-A bind to LPS via its carbohydrate-recognition domain and fibrinogen-like domain, respectively, whereby cytokine production by LPS-mediated TLR4 in mBMMCs appears to be down-regulated, indicating that mouse MBL and ficolin may have an inhibitory function toward mouse TLR4-mediated excessive inflammation on the mast cells.

Factors influencing epitaxial growth of three-dimensional Ge quantum dot crystals on pit-patterned Si substrate

We investigated the molecular beam epitaxy growth of three-dimensional (3D) Ge quantum dot crystals (QDCs) on periodically pit-patterned Si substrates. A series of factors influencing the growth of QDCs were investigated in detail and the optimized growth conditions were found. The growth of the Si buffer layer and the first quantum dot (QD) layer play a key role in the growth of QDCs. The pit facet inclination angle decreased with increasing buffer layer thickness, and its optimized value was found to be around 21°, ensuring that all the QDs in the first layer nucleate within the pits. A large Ge deposition amount in the first QD layer favors strain build-up by QDs, size uniformity of QDs and hence periodicity of the strain distribution; a thin Si spacer layer favors strain correlation along the growth direction; both effects contribute to the vertical ordering of the QDCs. Results obtained by atomic force microscopy and cross-sectional transmission electron microscopy showed that 3D ordering was achieved in the Ge QDCs with the highest ever areal dot density of 1.2 × 10(10) cm(-2), and that the lateral and the vertical interdot spacing were ~10 and ~2.5 nm, respectively.

Collectin-11/MASP complex formation triggers activation of the lectin complement pathway--the fifth lectin pathway initiation complex

Collectins and ficolins are important in the clearance of endogenous and exogenous danger materials. A new human collectin-11 was recently identified in low concentration in serum in complex with mannose-binding lectin (MBL)/ficolin-associated serine proteases. Collectin-11 binds to carbohydrate residues present on various microorganisms. Thus, we hypothesized that collectin-11 could be a novel initiation molecule in the lectin pathway of complement. We can show that collectin-11 associates with all the known MBL-associated serine proteases (MASP-1, MASP-2 and MASP-3) as well as the lectin complement pathway regulator MAP-1. Furthermore, we found that complex formation between recombinant collectin-11 and recombinant MASP-2 on Candida albicans leads to deposition of C4b. Native collectin-11 in serum mediated complement activation and deposition of C4b and C3b, and formation of the terminal complement complex on C. albicans. Moreover, spiking collectin-11-depleted serum, which did not mediate complement activation, with recombinant collectin-11 restored the complement activation capability. These results define collectin-11 as the fifth recognition molecule in the lectin complement pathway in addition to MBL, ficolin-1, ficolin-2 and ficolin-3.

Light absorption engineering of hydrogenated nanocrystalline silicon by femtosecond laser

The light absorption coefficient of hydrogenated nanocrystalline silicon has been engineered to have a Gaussian distribution by means of absorption modification using a femtosecond laser. The absorption-modified sample exhibits a significant absorption enhancement of up to ∼700%, and the strong absorption does not depend on the incident light. We propose a model responsible for this interesting behavior. In addition, we present an optical limiter constructed through this absorption engineering method.

The interaction pattern of murine serum ficolin-A with microorganisms

The ficolins are soluble pattern recognition molecules in the lectin pathway of complement, but the spectrum and mode of interaction with pathogens are largely unknown. In this study, we investigated the binding properties of the murine serum ficolin-A towards a panel of different clinical relevant microorganisms (N = 45) and compared the binding profile with human serum ficolin-2 and ficolin-3. Ficolin-A was able to bind Gram-positive bacteria strains including E. faecalis, L. monocytogenes and some S. aureus strains, but not to the investigated S. agalactiae (Group B streptococcus) strains. Regarding Gram-negative bacteria ficolin-A was able to bind to some E. coli and P. aeruginosa strains, but not to the investigated Salmonella strains. Of particular interest ficolin-A bound strongly to the pathogenic E. coli, O157:H7 and O149 strains, but it did not bind to the non-pathogenic E. coli, ATCC 25922 strain. Additionally, ficolin-A was able to bind purified LPS from these pathogenic strains. Furthermore, ficolin-A bound to a clinical isolate of the fungus A. fumigatus. In general ficolin-2 showed similar selective binding spectrum towards pathogenic microorganisms as observed for ficolin-A indicating specific pathophysiological roles of these molecules in host defence. In contrast, ficolin-3 did not bind to any of the investigated microorganisms and the anti-microbial role of ficolin-3 still remains elusive.

Adenosine derived from Staphylococcus aureus-engulfed macrophages functions as a potent stimulant for the induction of inflammatory cytokines in mast cells

In this study, we attempted to isolate novel mast cell-stimulating molecules from Staphylococcus aureus. Water-soluble extract of S. aureus cell lysate strongly induced human interleukin- 8 in human mast cell line-1 and mouse interleukin-6 in mouse bone marrow-derived mast cells. The active molecule was purified to homogeneity through a C(18) reverse phase HPLC column. By determination of its structure by MALDITOF and (1)H- and (13)C-NMR, adenosine was revealed to be responsible for the observed cytokine induction activities. Further studies using 8-sulfophenyl theophylline, a selective adenosine receptor blocker, verified that purified adenosine can induce interleukin-8 production via adenosine receptors on mast cells. Moreover, adenosine was purified from S. aureusengulfed RAW264.7 cells, a murine macrophage cell line, used to induce phagocytosis of S. aureus. These results show a novel view of the source of exogenous adenosine in vivo and provide a mechanistic link between inflammatory disease and bacterial infection.

Tunable nonlinear absorption of hydrogenated nanocrystalline silicon

Nonlinear absorption (NLA) of hydrogenated nanocrystalline silicon (nc-Si:H) has been investigated through the open aperture Z-scan method for the photon energy of the incident irradiance slightly less than the bandgap of the sample. NLA responses have been observed to be highly sensitive to the wavelength and intensity of the incident irradiance as well as to the bandgap of the sample, indicating greatly tunable NLA of nc-Si:H. The band tail of nc-Si:H appears to play a crucial role in such NLA responses.

Heterocomplexes of mannose-binding lectin and the pentraxins PTX3 or serum amyloid P component trigger cross-activation of the complement system

The long pentraxin 3 (PTX3), serum amyloid P component (SAP), and C-reactive protein belong to the pentraxin family of pattern recognition molecules involved in tissue homeostasis and innate immunity. They interact with C1q from the classical complement pathway. Whether this also occurs via the analogous mannose-binding lectin (MBL) from the lectin complement pathway is unknown. Thus, we investigated the possible interaction between MBL and the pentraxins. We report that MBL bound PTX3 and SAP partly via its collagen-like domain but not C-reactive protein. MBL-PTX3 complex formation resulted in recruitment of C1q, but this was not seen for the MBL-SAP complex. However, both MBL-PTX3 and MBL-SAP complexes enhanced C4 and C3 deposition and opsonophagocytosis of Candida albicans by polymorphonuclear leukocytes. Interaction between MBL and PTX3 led to communication between the lectin and classical complement pathways via recruitment of C1q, whereas SAP-enhanced complement activation occurs via a hitherto unknown mechanism. Taken together, MBL-pentraxin heterocomplexes trigger cross-activation of the complement system.

Preliminary studies on space charge compensation by analyzing residual argon gas ion signals

An experimental method is related to research the space charge compensation (SCC) effect in low energy intense proton beams by analyzing residual gas (RG) ion signals. The signal curves were measured with an energy spectrometer under the RG pressure from 1.2x10(-3) to 1.6x10(-2) Pa. Most of the data showed a similar trend with our theoretical predicts. From the RG ion energy spectra the potential distribution in the beam was calculated both with and without the SCC effect. Moreover, as a preliminary result, a best compensating point is achieved for the low energy beam transport transmission of 40 KeV, 60 mA H(+) beam in Peking University.

Synergy between ficolin-2 and pentraxin 3 boosts innate immune recognition and complement deposition

The long pentraxin 3 (PTX3) is a multifunctional soluble pattern recognition molecule that is crucial in innate immune protection against opportunistic fungal pathogens such as Aspergillus fumigatus. The mechanisms that mediate downstream effects of PTX3 are largely unknown. However, PTX3 interacts with C1q from the classical pathway of the complement. The ficolins are recognition molecules of the lectin complement pathway sharing structural and functional characteristics with C1q. Thus, we investigated whether the ficolins (Ficolin-1, -2, and -3) interact with PTX3 and whether the complexes are able to modulate complement activation on A. fumigatus. Ficolin-2 could be affinity-isolated from human plasma on immobilized PTX3. In binding studies, Ficolin-1 and particularly Ficolin-2 interacted with PTX3 in a calcium-independent manner. Ficolin-2, but not Ficolin-1 and Ficolin-3, bound A. fumigatus directly, but this binding was enhanced by PTX3 and vice versa. Ficolin-2-dependent complement deposition on the surface of A. fumigatus was enhanced by PTX3. A polymorphism in the FCN2 gene causing a T236M amino acid change in the fibrinogen-like binding domain of Ficolin-2, which affects the binding to GlcNAc, reduced Ficolin-2 binding to PTX3 and A. fumigatus significantly. These results demonstrate that PTX3 and Ficolin-2 may recruit each other on pathogens. The effect was alleviated by a common amino acid change in the fibrinogen-like domain of Ficolin-2. Thus, components of the humoral innate immune system, which activate different complement pathways, cooperate and amplify microbial recognition and effector functions.

The genetics of ficolins

Ficolins constitute a family of proteins whose biological role has been an enigma for many years. Over the past few years it has become evident that ficolins are part of the innate immune system and function as recognition molecules in the complement system. The 3 human ficolins, ficolin-1 (M-ficolin), ficolin-2 (L-ficolin) and ficolin-3 (H-ficolin or Hakata antigen) are encoded by the FCN1, FCN2 and FCN3 genes, respectively. Phylogenetic studies suggest that ficolins are of ancient origin. Ficolin-3 seems to be the most ancient molecule, from a phylogenetic perspective. Searches in databases and phylogenetic tree analysis demonstrate that the ficolin precursor has gone through an expansion involving independent duplication events in the different branches of the evolutionary tree. Of particular interest is the prediction that ficolin-1 appears to be present as an ortholog molecule. All human FCN genes are polymorphic. The FCN2 gene encoding ficolin-2, contains polymorphisms that affect ligand binding, while differences in the serum levels are associated with promoter polymorphisms. Recently, a frame-shift variation in the FCN3 gene was described, leading to ficolin-3 deficiency and defective complement activation. This FCN3 variation was also shown to be associated with immunodeficiency. This survey summarizes the current phylogenetic and inter-individual molecular understanding of the FCN genes.

MBL2, FCN1, FCN2 and FCN3-The genes behind the initiation of the lectin pathway of complement

Mannose-binding lectin (MBL) and the ficolins (Ficolin-1, Ficolin-2 and Ficolin-3) are soluble collagen-like proteins that are involved in innate immune defence. They bind sugar structures or acetylated compounds present on microorganisms and on dying host cells and they initiate activation of the lectin complement pathway in varying degrees. Common variant alleles situated both in promoter and structural regions of the human MBL gene (MBL2) influence the stability and the serum concentration of the protein. Although not as thoroughly investigated as the MBL2 gene polymorphisms the ficolin genes (FCNs) also exhibit genetic variations affecting both the serum concentration, stability and binding capacity of the corresponding proteins. Epidemiological studies have suggested that the genetically determined variations in MBL serum concentrations influence the susceptibility to and the course of different types of diseases, while the importance of the ficolins in general and the genetic variation in the FCNs genes in particular is still largely unresolved. This overview will summarize the current molecular knowledge of the human MBL2, FCN1, FCN2 and FCN3 genes.

Characterization of a polymorphism in the coding sequence of FCN3 resulting in a Ficolin-3 (Hakata antigen) deficiency state

Ficolin-3 (Hakata antigen or H-ficolin) is a soluble pattern recognition molecule in the lectin complement pathway. We speculated whether common genetic variations in the FCN3 gene contribute to deficiency of Ficolin-3. The FCN3 gene was sequenced in 237 healthy Danish Caucasians. The relevance of polymorphisms was assessed with antibodies against Ficolin-3 in a novel ELISA system and by production of recombinant Ficolin-3 variants. Ficolin-3 serum profiles were analyzed by SDS-PAGE and western blotting. Ficolin-3 serum concentration varied 10-fold (median, 24microg/ml; range, 3-54microg/ml). Out of several polymorphisms one FCN3+1637delC causing a reading frame shift and a distortion of the C-terminal end of the molecule with an allele frequency of 0.011 was particularly interesting. In individuals heterozygous for the FCN3+1637delC deletion lowered Ficolin-3 concentration was observed (P=0.025). SDS-PAGE and western blotting of serum revealed a weak band corresponding to the truncated molecule in addition to the normal Ficolin-3 pattern. Characterization of recombinant Ficolin-3 derived from FCN3+1637delC showed that in the homozygous situation this allelic variant would lead to Ficolin-3 deficiency. In conclusion an FCN3+1637delC deletion variant disrupting the possibility for pattern recognition was detected. Characterization of recombinant variant Ficolin-3 shows that homozygosity for the FCN3+1637delC deletion may lead to Ficolin-3 deficiency and may thus be the basis for a novel complement deficiency state.

[On molecular identification and taxonomic status of Anopheles lesteri and Anopheles anthropophagus in China (Diptera: Culicidae)]

OBJECTIVE

To clarify the taxonomic status of Anopheles lesteri and An. anthropophagus in China.

METHODS

Using molecular identification (PCR assay and rDNA-ITS2 sequencing) to examine the field anopheline mosquito specimens from Liaoning and Shandong. According to the ITS2 sequences, molecular phylogenetic tree was made.

RESULTS

According to the molecular identification, An. lesteri and An. anthropophagus were distributed both in Liaoning Province and Shandong Province. The length and GC content of rDNA-ITS2 sequence were 451 bp, 46.2% in An. lesteri (n = 6), and 448 bp, 46.0% in An. anthropophagus (n = 10), respectively. The ITS2 sequences from presentation sites were same in An. lesteri, while the intraspecies difference in An. anthropophagus was 0.88%. The specific difference between An. lesteri and An. anthropophagus was 25.7%. By analyzing molecular phylogenetic tree, the relationship between An. lesteri and An. sinensis, An. anthropophagus and An. liangshanensis was found to be closer.

CONCLUSION

According to the molecular identification, it was defined that An. lesteri and An. anthropophagus were sympatric independent species in China.

Protective effect of a prosaposin-derived, 18-mer peptide on slowly progressive neuronal degeneration after brief ischemia

Slowly progressive degeneration of the hippocampal CA1 neurons was induced by 3-minute transient global ischemia in gerbils. Sustained degeneration of hippocampal CA1 neurons was evident 1 month after ischemia. To investigate the effects of an 18-mer peptide comprising the hydrophilic sequence of the rat saposin C domain (18MP) on this sustained neuronal degeneration, an intracerebroventricular 18MP infusion was initiated 3 days after ischemia. Histopathologic and behavior evaluations were conducted 1 week and 1 month after induction of ischemia. When compared with the vehicle infusion, 18MP treatment significantly increased the response latency time in a passive avoidance task. Increased neuronal density was also evident, as was the number of intact synapses in the hippocampal CA1 region at 1 week and 1 month after ischemia. 18MP treatment also significantly decreased the number of TUNEL-positive CA1 neurons 1 week after ischemia. Subsequent in vitro experiments using cultured neurons demonstrated that the 18MP at optimal extracellular concentrations of 1 to 100 fg/mL prevented nitric oxide-induced neuronal damage as expected and significantly up-regulated the expressions of bcl-x(L) mRNA and its translated protein. These results suggest that the gerbil model of 3-minute ischemia is useful in studying the pathogenesis of slowly progressive neuronal degeneration after stroke and in evaluating effects of novel therapeutic agents. It is likely that the 18MP at low extracellular concentrations prevents neuronal apoptosis possibly through up-regulation of the mitochondrial antiapoptotic factor Bcl-x(L).