Passive recruitment of circulating leukocytes into capillary sprouts from existing capillaries in a microfluidic system

Recent evidence implicating leukocytes in angiogenesis raises the question of whether leukocytes and other cells circulating with the blood in microvascular networks can home to capillary sprouts intraluminally. This study describes an investigation of leukocyte trafficking in sprouting capillaries fabricated using soft lithography. The leukocytes passing with whole blood through existing capillaries were able to enter microfabricated capillary sprouts of variable length and sprouting angle due to the mechanical interaction with red blood cells (RBCs) at the sprouting bifurcation, in spite of the complete absence of blood flow through the blind-ended sprouts or any chemoattractants. The RBCs formed "comet tails" (the densely packed cellular trains forming behind leukocytes as they move through narrow capillaries) and effectively pushed leukocytes into the microfabricated sprouts while bypassing them at the sprouting bifurcation. Individual sprouts filled with several leukocytes, as wells as RBCs and platelets, were observed. The results of this study suggest that (i) blood cells are likely present in capillary sprouts throughout their development, (ii) leukocytes and other circulating cells may use this mechanism to home to capillary sprouts intraluminally for direct engraftment, and (iii) tissues may use this phenomenon as another mechanism for local recruitment of leukocytes from the blood stream.     

Microvasculature of the olfactory organ in the Japanese monkey (Macaca fuscata fuscata).

Olfaction is an important and primitive sense. As its importance has changed with evolution, anatomic adjustments have occurred in its structure and vasculature. Primates are a family of vertebrates that have had to develop their visual system to adapt to the arboreal environment and have evolved from a macrosmatic to a microsmatic species as the optic system has enlarged. This has resulted in anatomic changes of a small but critical area at the base of the brain. This paper describes the three-dimensional vascular anatomy of the olfactory organ of the Japanese monkey (Macaca fuscata fuscata). This is best understood by dividing the organ into three parts: the olfactory tract, olfactory bulb, and olfactory nerves in the nasal mucosa. The bulb can be partitioned into an outer or cortical part and inner or medullary part. The vasculature and tissue were examined grossly and with light microscopy and scanning electron microscopy of vascular corrosion casts. The olfactory tract and bulb were supplied by an arteriole from the anterior cerebral artery on each side. The tract was supplied by capillaries running spirally with a coarse network. At the olfactory bulb, the arteriole ramified into the intracortical and medullary branches that formed capillary networks. The bulbar intracortical capillaries were divided into two layers with different densities and vascular patterns. The capillaries of the superficial layer had a ladder-like pattern. The branches that ran into the medulla of the olfactory bulb were more widely spaced. Twigs from the posterior ethmoidal artery ran along the nerve fiber and formed intra- and extrafascicular networks. Each region of the olfactory organ had characteristic three-dimensional vascular patterns that were related to their cellular architecture.     

FTIR spectro-imaging of collagen scaffold formation during glioma tumor development

Evidence has recently emerged that solid and diffuse tumors produce a specific extracellular matrix (ECM) for division and diffusion, also developing a specific interface with microvasculature. This ECM is mainly composed of collagens and their scaffolding appears to drive tumor growth. Although collagens are not easily analyzable by UV-fluorescence means, FTIR imaging has appeared as a valuable tool to characterize collagen contents in tissues, specially the brain, where ECM is normally devoid of collagen proteins. Here, we used FTIR imaging to characterize collagen content changes in growing glioma tumors. We could determine that C6-derived solid tumors presented high content of triple helix after 8–11 days of growth (typical of collagen fibrils formation; 8/8 tumor samples; 91 % of total variance), and further turned to larger α-helix (days 12–15; 9/10 of tumors; 94 % of variance) and β-turns (day 18–21; 7/8 tumors; 97 % of variance) contents, which suggest the incorporation of non-fibrillar collagen types in ECM, a sign of more and more organized collagen scaffold along tumor progression. The growth of tumors was also associated to the level of collagen produced (P?<?0.05). This study thus confirms that collagen scaffolding is a major event accompanying the angiogenic shift and faster tumor growth in solid glioma phenotypes.     

FT-IR spectral imaging of blood vessels reveals protein secondary structure deviations induced by tumor growth

Vascular basement membrane remodeling is involved in tumor angiogenesis to enable tumor invasion and growth. FT-IR spectral imaging was used to determine changes in tumor blood vessels to reveal protein secondary structure in Rag-gamma immuno-deficient mice sacrificed 14 and 21 days after subcutaneous glioma implantation. For the oldest blood capillaries (diameter >20 microns), tumor growth induced a decrease in triple-helix content (1638 cm(-1); -7.3%; P < 0.05) and an increase in beta turns (1666 and 1615 cm(-1); +4%; P < 0.01). These protein-structure alterations, mainly from type IV collagen, reflected the high angiogenic stress of growing tumors. We propose to use these molecular markers of vascular basement membrane protein alterations for gradation of solid tumors by FT-IR spectral imaging.     

TUMOR DESTRUCTION IN PHOTODYNAMIC THERAPY

Abstract The effects of photodynamic therapy (PDT) on the tumor microvasculature in the first few hours after treatment was studied at the light microscope (LM) and electron microscope (EM) levels in DBA/2Ha mice bearing SMT-F tumors. Animals received intraperitoneal injections of 10 mg kg⁻ of Photofrin II and 24 h later tumors were treated with 100 J cm⁻² of light (630 nm). Animals were sacrificed and their tumors removed at time 0, 30 min, 1, 2, 4, 8, 16 and 24 h after treatment. The results indicate that the effects of PDT are initially direct destruction of the microfibrils in the subendothelial zone of the tumor capillaries with subsequent tumor cell death secondary to hemorrhage and vascular collapse.     

Structure and stability of the defect fullerene clusters of C60: C59, C58, and C57

We have performed density functional calculations for the structures and stabilities of various isomers of the defect fullerene clusters of C(60): C(59), C(58), and C(57). The C(59_)5-8, C(58_)5-5-7, and C(57_)4-5-9 clusters were calculated to be the most stable isomers of the C(59), C(58), and C(57) clusters, respectively. There are obvious relationships between structure and stability of the defect fullerene clusters. First, an unsaturated carbon atom favors being located at a 6-membered ring rather than a 5-membered ring. Second, the most stable isomers prefer to have newly formed 5-membered rings, rather than newly formed 4-membered rings.     

Protective Effect of Dermal Brimonidine Applications Against UV Radiation‐induced Skin Tumors,Epidermal Hyperplasia and Cell Proliferation in the Skin of Hairless Mice

Brimonidine at 0.18%, 1% and 2% concentrations applied topically in hairless mice significantly decreased tumor burden and incidences of erythema, flaking, wrinkling and skin thickening induced by UVR. The unbiased median week to tumor ≥1 mm was increased by the 1% and 2% concentrations. The tumor yield was reduced by all concentrations at week 40 for all tumor sizes but the ≥4 mm tumors with the 0.18% concentration. At week 52, the tumor yield was reduced for all tumor sizes and all brimonidine concentrations. The tumor incidence was reduced by all concentrations at week 40 for all tumor sizes, but the ≥4 mm tumor with the 0.18% concentration and at week 52 for all tumor sizes with the 1% and 2% concentrations and with the 0.18% concentration only for the ≥4 mm tumors. Reductions in ≥4 mm tumor incidences compared to the vehicle control group were 54%, 91% and 86% by week 52 for the 0.18%, 1% and 2% concentrations, respectively. Brimonidine at 2% applied 1 h before or just after UVB irradiation on hairless mice decreased epidermal hyperplasia by 23% and 32% and epithelial cell proliferation by 59% and 64%, respectively, similar to an epidermal growth factor receptor (EGFR) inhibitor.     

Functionalized semiconductor nanocrystals for ultrasensitive detection of peptides

Semiconductor CdS nanoparticle have been prepared and modified with thiovanic acid. The functionalized nanoparticles are water-soluble. They were used as the fluorescence probes in the ultrasensitive detection of peptides. This method is based on the fluorescence enhancement of functionalized nano-CdS in the presence of peptide with mercapto groups (GN-9) and the fluorescence quenching of functionalized nano-CdS in the presence of peptide (GA-8 and MT-25). Excitation and emission wavelengths were 360 and 530 nm, respectively. Under optimum conditions, the calibration graphs are linear over the range of 0.15-3.5, 0.2-4.0, and 0.2-3.8 μg ml⁻¹ for GN-9, GA-8 and MT-25, respectively. The corresponding detection limits were 0.010 μg ml⁻¹ for GN-9, 0.018 μg ml⁻¹ for GA-8 and 0.022 μg ml⁻¹ for MT-25, respectively. This method has been proved to be a simple, rapid and sensitive method.     

In vivo resistance to photofrin-mediated photodynamic therapy in radiation-induced fibrosarcoma cells resistant to in vitro Photofrin-mediated photodynamic therapy.

The effects of Photofrin-mediated photodynamic therapy (PDT) on the in vitro cell survival and in vivo tumor growth of murine radiation-induced fibrosarcoma (RIF) cell tumors have been examined following in vivo PDT treatment of tumors. The response to in vivo PDT is examined in tumors derived from RIF-1 mouse fibrosarcoma cells and in tumors derived from RIF-8A cells, which show in vitro resistance to PDT. A significant reduction in tumor volume is observed over the first three days following in vivo PDT treatment of either 5 or 10 mg/ kg. The reduction in tumor volume is greater for a 10 compared to a 5 mg/ml dose and occurs to a similar extent for both RIF-1 and RIF-8A tumors. The re-growth is significantly delayed for RIF-1 compared to RIF-8A tumors, indicating a greater response for RIF-1 tumors compared to RIF-8A tumors following PDT. A reduced response of the RIF-8A compared to the RIF-1 tumor cells is also observed in the clonogenic survival of cells from tumors that were excised and explanted in vitro immediately following in vivo PDT treatment. These data indicate that the intrinsic cell sensitivity to PDT is an important component in the mechanism that leads to tumor response following in vivo photodynamic therapy.     

Low-angle light scattering of ionotropic gels

Low-angle light-scattering patterns were obtained on ionotropic gels formed by the diffusion of Ca⁺⁺ into a polygalacturonate sol. Near the sol–gel boundary, diffraction patterns were obtained which indicated organized structures with repeating units of 1100, 250, and 12.5 μ. Microscopic investigations confirmed that at this gel boundary capillaries run parallel to each other and perpendicular to the direction of diffusion. The diameter of capillaries was 12 μ while their length was in the 1000 μ range. Short interconnecting capillaries were about 200–300 μ in length. Inside the gel, in the more highly crosslinked parts, a disorientation occurs during the aging process with the partial disappearance of capillaries. However, at the gel–sol and gel–semipermeable membrane boundaries, the highly organized structures remain even during prolonged aging. The kinetics of the gel formation was also investigated.     

Synthesis and In vitro Antitumor Screening of Novel 2,7‐Naphthyridine‐3‐carboxylic Acid Derivatives

New derivatives of 2,7‐naphthyridine‐3‐carboxylic acid were synthesized. We report the hydrolysis, chlorination, alkylation, and amination of the 2,7‐naphthyridine esters 1 , 2 . A series of Schiff's bases 8a , 8b , 8c , 8d , 8e , 8f , 8g , 8h , 8i , 8j , 9a , 9b , 9b' , 9c , 9d , 9e were produced by treating the obtained hydrazides 6 and 7 with aromatic aldehydes. The anticancer activities of the obtained derivatives were examined. Eighteen of the 24 newly synthesized compounds were qualified by the National Cancer Institute NCI (Bethesda, MD, USA) for in vitro screening against 60 different human tumor cell lines. The most active compound 8i was evaluated against a 60‐cell panel at five concentration levels and proved to be most sensitive towards central nervous system cancer (SF‐539), with GI₅₀ = 0.70 µmol, total growth inhibition = 5.41 µmol, and LC₅₀ = 53.7 µmol.     

Metal speciation using capillary electrophoresis--inductively coupled plasma atomic emission spectrometry and polytetrafluoroethylene capillaries

A capillary electrophoresis--inductively coupled plasma atomic-emission spectrometry (CE-ICP-AES) system using a polytetrafluoroethylene (PTFE) capillary has been developed. The CE-ICP interface was a modified concentric nebulizer. The PTFE capillary (50 microm internal diameter) was used as the central capillary of the nebulizer. Using the PTFE capillaries, the solution flow rate induced by the carrier gas flow was smaller than that of glass capillary. Solution flow was mainly induced by the CE electric field. Baseline separation of Ba2+/Mg2+ ion pair using simple buffer solution of 0.014 M sodium acetate was reported. Separation and correlation of metal species in metallothioneins (MT-1 and MT-2 in MT) of rabbit liver using the CE-ICP system were also discussed.     

The synergistic effects of CXCR4 and EGFR on promoting EGF-mediated metastasis in ovarian cancer cells

CXC chemokine receptor 4 (CXCR4) is a cell surface receptor that has been reported to mediate the metastasis of many solid tumors including ovarian, breast, lung and prostate. The over-expression of the epidermal growth factor receptor (EGFR) is associated with the majority of ovarian cancer and has been implicated in the process of malignant transformation by promoting cell proliferation, survival, and motility. In this research, the result first showed that epidermis growth factor (EGF) enhanced the expression of CXCR4 and the migration of ovarian cancer cells, moreover, both stromal cell derived factor-1alpha (SDF-1alpha) and EGF-induced high matrix metallopeptidase 9 (MMP9) expressions. Molecular analysis indicated that augmented CXCR4 and MMP9 expression was regulated by phosphatidylinositol-3-kinase(PI3K)/Akt signal transduction pathway. These results suggested a possible important "cross-talk" between CXCR4 and EGFR intracellular pathways that might link signals of tumor deteriorated and provided a plausible explanation for the poor overall survival rate of patients whose co-expression of CXCR4 and EGFR was detected in their tissue sections. It enlightened that, compared to the respective inhibition of the EGFR or CXCR4 signaling, the simultaneous inhibition of them might be a more useful therapeutic strategy of cancer.     

Epigallocatechin-3-gallate inhibits photocarcinogenesis through inhibition of angiogenic factors and activation of CD8+ T cells in tumors

There has been considerable interest in the use of botanical supplements to protect skin from the adverse effects of solar UV radiation, including photocarcinogenesis. We and others have shown that topical application of (-)-epigallocatechin-3-gallate (EGCG) from green tea prevents photocarcinogenesis in mice; however, the chemopreventive mechanism of EGCG in an in vivo tumor model is not clearly understood. In this study, UV-B-induced skin tumors with and without treatment of EGCG ( approximately 1 mg/cm(2)) and age-matched skin biopsies from SKH-1 hairless mice were used to identify potential molecular targets of skin cancer prevention by EGCG. These biopsies were analyzed for various biomarkers of angiogenesis and antitumor immune response using immunostaining, Western blotting and gelatinolytic zymography. We report that compared to non-EGCG-treated tumors, topical application of EGCG in UV-induced tumors resulted in inhibition of protein expression and activity of matrix metalloproteinase (MMP)-2 and MMP-9, which play crucial roles in tumor growth and metastasis. In contrast, tissue inhibitor of MMP-1 (TIMP-1), which inhibits MMP activity, was increased in tumors. With respect to the tumor vasculature, EGCG decreased the expression of CD31, a cell surface marker of vascular endothelial cells, and inhibited the expression of vascular endothelial growth factor in tumors, which are essential for angiogenesis. EGCG inhibited proliferating cell nuclear antigen in UV-B-induced tumors as well. Additionally, higher numbers of cytotoxic T lymphocytes (CD8(+) T cells) were detected in EGCG-treated tumors compared with non-EGCG-treated tumors. Together, these in vivo tumor data suggested that inhibition of photocarcinogenesis in mice by EGCG is associated with inhibition of angiogenic factors and induction of antitumor immune reactivity.     

Natural Products in Preventing Tumor Drug Resistance and Related Signaling Pathways

Drug resistance is still an obstacle in cancer therapy, leading to the failure of tumor treatment. The emergence of tumor drug resistance has always been a main concern of oncologists. Therefore, overcoming tumor drug resistance and looking for new strategies for tumor treatment is a major focus in the field of tumor research. Natural products serve as effective substances against drug resistance because of their diverse chemical structures and pharmacological effects. We reviewed the signaling pathways involved in the development of tumor drug resistance, including Epidermal growth factor receptor (EGFR), Renin-angiotensin system (Ras), Phosphatidylinositol-3-kinase/protein kinase B (PI3K/Akt), Wnt, Notch, Transforming growth factor-beta (TGF-β), and their specific signaling pathway inhibitors derived from natural products. This can provide new ideas for the prevention of drug resistance in cancer therapy.     

Photodynamic Therapy with Topical dL-aminolevulinic Acid Delays UV Photocarcinogenesis in Hairless Mice

Abstract— Photodynamic therapy (PDT) with topical application of 8-aminolevulinic acid (ALA) followed by irradiation with visible light (ALA-PDT) is a relatively new and promising experimental treatment of superficial premalignant and malignant skin neoplasms. The purpose of this study was to determine whether ALA-PDT can prevent photocarcinogenesis in hairless mice exposed to solar UV. A total of 140 mice was divided into seven groups of 20 mice each. Group 1: solar-UV exposure. Group 2: solar UV and a cream base + visible light once a week. Group 3: solar UV and ALA-PDT once a week. Group 4: solar UV and ALA-PDT once every second week. Group 5: solar UV and ALA-PDT every fourth week. Group 6: ALA-PDT once a week. Group 7: no treatment. The time to first and to second tumor 1 mm was registered. Predefined endpoints, such as one tumor a 4 mm or an area of small confluent tumors on the back of the mice were criteria for withdrawal from the experiment. The time to first and to second tumor was significantly longer in the ALA-PDT-treated mice than in mice only exposed to solar UV and solar-UV/cream base-visible light (P < 0.005). However, we observed an increased death and accident rate in the ALA-PDT-treated groups compared to the groups not treated with ALA-PDT (chi-square test, P = 0.0250). Significantly more ALA-PDT-treated mice were withdrawn because of a tumor 4 mm ( P = 0.0005). The UV unexposed mice developed no tumors. Repetitive treatments with ALA-PDT delay photoinduced carcinogenesis in mice.     

Synthesis and biological assessment of some fused Pyran derivatives

Pyran was formed by reacting methyl 3-methoxyacrylate (1) with 2-benzylidenemalanonitrile to form compound 2 . The pyrano derivatives 3–6 were obtained by reacting the second molecule with 2-benzylidenemalanonitrile, carbon disulfide, formamide, and benzylidene cyclohexanone. Compound (2) interacted with ethyl chloroacetate to form compound 8 , which then cyclized in the presence of sodium ethoxide to form compound 9 . Compound 7 was formed when compound (2) was treated with acetic acid in the presence of sulfuric acid and reacted with ethylchloroacetate to form compound 10 and then was converted to compound 11 by the addition of sodium ethoxide. Analytical and spectral data have been used to determine the structures of the newly synthesized substances and they were then tested for their antibacterial and antioxidant activities. In terms of antioxidant activity, compounds 2 and 8 were found to have the greatest and lowest levels, respectively, against Enterobacter aerogenes.     

Plant coumarins. IX.* Phenolic compounds of <Emphasis Type="Italic">Ferulopsis hystrix</Emphasis> growing in Mongolia. Cytotoxic activity of 8,9-dihydrofurocoumarins

It was shown that plants of the genus Ferulopsis are valuable sources of coumarins. Nine angular 8-substituted and 8,9-disubstituted 8,9-dihydrofurocoumarins were isolated. The cytotoxicity of these compounds was studied on models of human CEM-13, MT-4, and U-937 tumor cells. X-ray structure data were obtained for peucenidin.     

Design of cerebellar and nontegmental rhombencephalic microvascular bed in the sterlet, Acipenser ruthenus: a scanning electron microscope and 3D morphometry study of vascular corrosion casts.

The design of the microvasculature of cerebellum and nontegmental rhombencephalic areas was studied in eight adult Acipenser ruthenus L. by scanning electron microscopy of vascular corrosion casts and three-dimensional morphometry. Gross vascularization was described and diameters and total branching angles of parent and daughter vessels of randomly selected arterial and capillary bifurcations (respectively, venous mergings) were measured. With diameters ranging from 15.9 +/- 1.9 microm (cerebellum; mean +/- S.D.) to 15.9 +/- 1.7 mm (nontegmental rhombencephalon; mean +/- S.D.) capillaries in Acipenser were significantly (p > or = .05) smaller than in cyclostomes (18-20 microm) but significantly thicker than in higher vertebrates and men (6-8 microm). With the exception of the area ratio beta (i.e., sum of squared daugther diameters divided by squared diameter of parent vessel) of the venular mergings in the nontegmental rhombencephalon, no significant differences (p > or = .05) existed between the two brain areas. Data showed that arteriolar and capillary bifurcations and venular mergings are optimally designed in respect to diameters of parent vessel to daughter vessels and to branching (merging) angles. Quantitative data are discussed both in respect to methodical pitfalls and the optimality principles possibly underlying the design of vascular bifurcations/mergings in selected brain areas of a nonteleost primitive actinopterygian fish.     

Half-metallic ferromagnetism in synthetic Co9Se8 nanosheets with atomic thickness

Controlling the synthesis of atomic-thick nanosheets of nonlayered materials is extremely challenging because of the lack of an intrinsic driving force for anisotropic growth of two-dimensional (2D) structures. In that case, control of the anisotropy such as oriented attachment of small building blocks during the reaction process will be an effective way to achieve 2D nanosheets. Those atomic-thick nanosheets possess novel electronic structures and physical properties compared with the corresponding bulk samples. Here we report Co(9)Se(8) single-crystalline nanosheets with atomic thickness and unique lamellar stacking formed by 2D oriented attachment. The atomic-thick Co(9)Se(8) nanosheets were found to exhibit intrinsic half-metallic ferromagnetism, as supported by both our experimental measurements and theoretical calculations. This work will not only open a new door in the search for new half-metallic ferromagnetic systems but also pave a practical way to design ultrathin, transparent, and flexible paperlike spintronic devices.