574-647 nm wavelength tuning by second-harmonic generation from diode-pumped PPKTP waveguides.

We present a compact, all-room-temperature continuous-wave laser source in the visible spectral region between 574 and 647 nm by frequency doubling of a broadly tunable InAs/GaAs quantum-dot external-cavity diode laser in a periodically poled potassium titanyl phosphate crystal containing three waveguides with different cross-sectional areas (4×4, 3×5, and 2 µm×6 µm). The influence of a waveguide's design on tunability, output power, and mode distribution of second-harmonic generated light, as well as possibilities to increase the conversion efficiency via an optimization of a waveguide's cross-sectional area, was systematically investigated. A maximum output power of 12.04 mW with a conversion efficiency of 10.29% at 605.6 nm was demonstrated in the wider waveguide with the cross-sectional area of 4 µm×4 µm.

Orange-to-red tunable picosecond pulses by frequency doubling in a diode-pumped PPKTP waveguide.

A compact picosecond all-room-temperature orange-to-red tunable laser source in the spectral region between 600 and 627 nm is demonstrated. The tunable radiation is obtained by second-harmonic generation in a periodically poled potassium titanyl phosphate (PPKTP) multimode waveguide using a tunable quantum-dot external-cavity mode-locked laser. The maximum second-harmonic output peak power of 3.91 mW at 613 nm is achieved for 85.94 mW of launched pump peak power at 1226 nm, resulting in conversion efficiency of 4.55%.

Carcinoembryonic antigen promotes tumor cell survival in liver through an IL-10-dependent pathway.

Most circulating tumor cells die within 24 h of entering the hepatic microvasculature because their arrest initiates an ischemia-reperfusion (I/R) injury that is cytotoxic. Human colorectal carcinomas (CRC) produce the glycoprotein Carcinoembryonic Antigen (CEA) that increases experimental liver metastasis in nude mice. Since CEA induces release of IL-6 and IL-10, we hypothesized that CEA inhibits the I/R injury through a Kupffer cell-mediated cytokine-dependent pathway. We assessed cytokine effects in CRC co-cultured with liver and in vivo. Human CRC prelabeled with fluorescent dyes were incubated with a reoxygenated suspension of ischemic nude mouse liver fragments in a bioreactor. CEA, rhIL-6 or rhIL-10 were either administered to the donor mice prior to hepatic ischemia or during co-culture. Liver donors were athymic nude or iNOS, IL-6 or IL-10 knock out mice. Ischemic-reoxygenated liver kills Clone A CRC through production of nitric oxide (NO) and superoxide anion. Treatment of liver donors with CEA prior to hepatic ischemia inhibited this in vitro cytotoxicity through an IL-10 and Kupffer cell dependent pathway that inhibited NF-kappaB activation, NO production and iNOS upregulation. IL-10 but not IL-6 enhanced CRC survival in nude mouse liver in vivo. Thus, CEA enhanced metastasis by inducing IL-10 to inhibit iNOS upregulation in host liver.

Highly efficient blue-light generation from a compact, diode-pumped femtosecond laser by use of a periodically poled KTP waveguide crystal.

We present a simplified, potentially portable, and highly efficient blue-light source from a periodically poled KTP waveguide crystal with a compact femtosecond Cr:LiSAF laser. This light source generates 5.6 mW of blue average output power at 424 nm with 27 mW of incident fundamental in a single-pass extracavity arrangement at room temperature. The overall system efficiency of electrical power to blue light is 0.5%, and the internal second-harmonic generation conversion efficiency is as high as 37%. The slope efficiency of 5.5% pJ(-1) at low pulse energies is, to our knowledge, the highest slope efficiency yet reported for frequency conversion into the blue spectral region.

Alterations of telomerase activity and terminal restriction fragment in gastric cancer and its premalignant lesions.

AIMS: In order to explore the role of alterations of telomerase activity and terminal restriction fragment (TRF) length in the development and progression of gastric cancer. METHODS: Telomerase activity was detected in 176 specimens of gastric mucosa obtained through an operation or endoscopical biopsy by using the telomeric repeat amplification protocol (TRAP) assay. Meanwhile, the mean length of TRF was measured with the use of a Southern blot in part of those samples. RESULTS: Telomerase activity was detected in 14 of 57 (24.6%) chronic atrophy gastritis patients, six of 18 (33.3%) intestinal metaplasia patients, three of eight (37.5%) dysplasia patients and 60 of 65 (92.3%) gastric cancer patients, respectively. Normal gastric mucosa revealed no telomerase activity. No association was found between telomerase activity and any clinicopathological parameters. The mean TRF length was decreased gradually with age in normal mucosa and in gastric cancer tissue. Regression analysis demonstrated that the reduction rate in these tissues was 41 +/- 12 base pairs/year. Among 35 gastric cancers, TRF length was shown to be shorter in 20 cases (57.1%), similar in 12 cases (34.3%) and elongated in three cases (7.6%), compared to the corresponding adjacent tissues. The mean TRF length tended to decrease as the mucosa underwent chronic atrophy gastritis, intestinal metaplasia, dysplasia and into gastric cancer. The mean TRF length in gastric cancer was not statistically correlated with clinicopathological parameters and telomerase activity. CONCLUSIONS: Our results suggest that telomerase is expressed during the early stage of gastric carcinogenesis, and that the clinical significance of TRF length appears to be limited in gastric cancer.

Galectin-3 protects human breast carcinoma cells against nitric oxide-induced apoptosis: implication of galectin-3 function during metastasis.

Galectin-3 is a beta-galactoside-binding protein which regulates many biological processes including cell adhesion, migration, cell growth, tumor progression, metastasis, and apoptosis. Although the exact function of galectin-3 in cancer development is unclear, galectin-3 expression is associated with neoplastic progression and metastatic potential. Since studies have suggested that tumor cell survival in microcirculation determines the metastatic outcome, we examined the effect of galectin-3 overexpression in human breast carcinoma cell survival using the liver ischemia/reperfusion metastasis model. While the majority of control cells died by hepatic ischemia/reoxygenation, nearly all of galectin-3 overexpressing cells survived. We showed that galectin-3 inhibits nitrogen free radical-mediated apoptosis, one of the major death pathways induced during hepatic ischemia/reperfusion. Galectin-3 inhibition of apoptosis involved protection of mitochondrial integrity, inhibition of cytochrome c release and caspase activation. Taking these results together with the previous observation that galectin-3 inhibits apoptosis induced by loss of cell adhesion, we propose that galectin-3 is a critical determinant for anchorage-independent and free radical-resistant cell survival during metastasis.

Replicating adenoviral vector-mediated transfer of a heat-inducible double suicide gene for gene therapy.

Tumor cells that express a fusion gene of Escherichia coli cytosine deaminase (CD) and herpes simplex virus type 1 thymidine kinase (TK) sequences activate and are subsequently killed by the nontoxic prodrugs 5-fluorocytosine and ganciclovir. We have previously developed a recombinant adenovirus containing the CD-TK fusion gene controlled by the human inducible heat shock protein 70 promoter so that heat at 41 degrees C for 1 hour induces therapeutic gene expression. This adenovirus effectively transduces heat-inducible expression of the CD-TK gene into human prostate carcinoma cells. However, because a limited number of cells in a tumor can actually be infected, we created a replicating adenoviral vector to increase CD-TK gene expression. This vector is a replication-competent, E1B-attenuated adenoviral vector containing the hsp70 promoter-driven CD-TK gene (Ad.E1A(+)HS-CDTK). When human prostate adenocarcinoma DU-145 cells (mutant p53) were infected with the virus at a multiplicity of infection (MOI) of 1 or 10, the viral replication was detected within 2 days at both MOIs. Similar results were observed in human colorectal carcinoma CX-1 cells. When DU-145 cells were infected with the virus at an MOI of 10, incubated for 24 hours, heated at 41 degrees C for 4 hours, and then harvested 20 hours later, Western blot analysis demonstrated that this virus successfully produced viral E1A proteins and heat shock stimulated the CD-TK gene expression by 12.3-fold. In addition, Ad.E1A(+)HS-CDTK effectively suppressed cell proliferation by viral cytopathic effect). Unlike with a replication-incompetent virus (Ad.HS-CDTK), the cytopathic effect of the virus and cytotoxicity in the presence of the prodrugs were still observed even at low MOI (MOI=1.0).

Chemically induced magnetism and magnetoresistance in La(0.8)Sr(1.2)Mn(0.6)Rh(0.4)O(4).

It is shown by magnetometry and microSR spectroscopy that short-range magnetic interactions between the Mn cations in the nonmetallic K(2)NiF(4)-like phase La(0.8)Sr(1.2)Mn(0.6)Rh(0.4)O(4) become significant below approximately 200 K. Negative magnetoresistance (rho/rho(0) approximately 0.5 in 14 T at 108 K) is apparent below this temperature. Neutron diffraction has shown that an applied magnetic field of 5 T is sufficient to induce saturated (3.38(7)mu(B) per Mn) long-range ferromagnetic ordering of the atomic moments at 2 K, and that the induced ordering persists up to a temperature of 50 K in 5 T. Spin glass behavior is observed below 20 K in the absence of an applied field. The induced magnetic ordering is attributed to the subtle changes in band structure brought about by the external field, and to the controlling influence of Rh(3+) over the relative strength of competing magnetic exchange interactions.

Control of magnetic ordering by Jahn--Teller distortions in Nd(2)GaMnO(6) and La(2)GaMnO(6).

The substitution of Ga(3+) into the Jahn--Teller distorted, antiferromagnetic perovskites LaMnO(3) and NdMnO(3) strongly affects both the crystal structures and resulting magnetic ordering. In both compounds the Ga(3+) and Mn(3+) cations are disordered over the six coordinate sites. La(2)GaMnO(6) is a ferromagnetic insulator (T(c) = 70 K); a moment per Mn cation of 2.08(5) mu(B) has been determined by neutron powder diffraction at 5 K. Bond length and displacement parameter data suggest Jahn--Teller distortions which are both coherent and incoherent with the Pnma space group symmetry of the perovskite structure (a = 5.51122(4) A, b = 7.80515(6) A, c = 5.52947(4) A) at room temperature. The coherent distortion is strongly suppressed in comparison with the parent LaMnO(3) phase, but the displacement ellipsoids suggest that incoherent distortions are significant and arise from local Jahn--Teller distortions. The preparation of the new phase Nd(2)GaMnO(6) has been found to depend on sample cooling rates, with detailed characterization necessary to ensure phase separation has been avoided. This compound also adopts the GdFeO(3)-type orthorhombically distorted perovskite structure (space group Pnma, a = 5.64876(1) A, b = 7.65212(2) A, c = 5.41943(1) A at room temperature). However, the B site substitution has a totally different effect on the Jahn--Teller distortion at the Mn(3+) centers. This phase exhibits a Q(2) mode Jahn--Teller distortion similar to that observed in LaMnO(3), although reduced in magnitude as a result of the introduction of Ga(3+) onto the B site. There is no evidence of a dynamic Jahn-Teller distortion. At 5 K a ferromagnetically ordered Nd(3+) moment of 1.06(6) mu(B) is aligned along the y-axis and a moment of 2.8(1) mu(B) per Mn(3+) is ordered in the xy plane making an angle of 29(2) degrees with the y-axis. The Mn(3+) moments couple ferromagnetically in the xz plane. However, along the y-axis the moments couple ferromagnetically while the x components are coupled antiferromagnetically. This results in a canted antiferromagnetic arrangement in which the dominant exchange is ferromagnetic. Nd(2)GaMnO(6) is paramagnetic above 40(5) K, with a paramagnetic moment and Weiss constant of 6.70(2) mu(B) and 45.9(4) K, respectively. An ordered moment of 6.08(3) mu(B) per Nd(2)GaMnO(6) formula unit was measured by magnetometry at 5 K in an applied magnetic field of 5 T.

Efficient frequency doubling of a pulsed laser diode by use of a periodically poled KTP waveguide crystal with Bragg gratings.

Blue light with an average power of as much as 7.5 mW in picosecond pulses has been generated at 486, 488, and 491 nm from a frequency-doubled, nonresonant injection seeded, gain-switched InGaAs/GaAs diode laser by use of a periodically poled KTP waveguide crystal that incorporates a Bragg grating section.

Microgravity culture reduces apoptosis and increases the differentiation of a human colorectal carcinoma cell line.

Our hypothesis is that rotation increases apoptosis in standard tissue culture medium at shear stresses of greater than approximately 0.3 dyn/cm2. Human MIP-101 poorly differentiated colorectal carcinoma cells were cultured for 6 d in complete medium in monolayers, on Teflon-coated nonadherent surfaces (static three-dimensional [3D]) or in rotating 3D cultures either in microgravity in low-earth orbit (3D microg) or in unit gravity on the ground (3D 1g). Apoptosis (determined morphologically), proliferation (by MIB1 staining), and the expression of epidermal growth-factor receptor (EGF-R), TGF-alpha, or TGF-beta were assessed by immunohistochemistry, while the expression of the differentiation marker carcinoembryonic antigen (CEA) was assessed on Western blots. Over the course of 6 d, static 3D cultures displayed the highest rates of proliferation and lowest apoptosis. This was associated with high EGF-R, TGF-alpha, and TGF-beta expression which was greater than that of a monolayer culture. Both rotated 3D lg and 3D microg cultures displayed lower expression of EGF-R, TGF-alpha, or TGF-beta and proliferation than that of monolayer or static 3D cultures. However, rotated 3D microg displayed significantly less apoptosis and greater CEA expression than rotated 3D 1g cultures. When rotated cultures of MIP-101 cells were grown uncler static conditions for another 3 d, proliferation increased and apoptosis decreased. Thus, rotation appears to increase apoptosis and decrease proliferation, whereas static 3D cultures in either unit or microgravity have less apoptosis, and reduced rotation in microgravity increases CEA expression.

Enhancement of embryogenic culture initiation from tissues of mature sweetgum trees.

Male inflorescences, female inflorescences, and leaves collected from dormant buds of three sweetgum (Liquidambar styraciflua) trees were tested for induction of somatic embryogenesis following treatment with thidiazuron, naphthaleneacetic acid (NAA) or different combinations of the two. Explants were placed into culture either within a few days after collection or following 2 months of storage at -15  °C. Although embryogenic cultures were obtained from all three trees, embryogenesis induction was strongly affected by genotype (source tree), with 100% of the staminate inflorescence explants from one tree producing embryogenic cultures in one experiment. Embryogenesis induction was also influenced by explant type, with staminate inflorescences up to five times more likely to produce an embryogenic culture than female inflorescences. No embryogenic cultures were obtained from leaf explants. While treatment with plant growth regulators was not required for embryogenesis induction from inflorescence explants, culture on medium with NAA alone resulted in the highest production of repetitively embryogenic cultures and cultures producing proembryogenic masses. Dormant buds stored for 2 months at -15  °C were still able to produce embryogenic cultures, although frozen storage decreased this ability by over one-half for staminate inflorescences.

Reactive nitrogen and oxygen radicals formed during hepatic ischemia-reperfusion kill weakly metastatic colorectal cancer cells.

Microscopic infarcts develop within the livers of athymic nude mice during the first 24 h after human colorectal carcinoma (CRC) cells arrest within hepatic sinusoids. Because these regions are reperfused, essentially all weakly metastatic clone A and MIP-101 CRC cells die, whereas many highly metastatic CX-1 CRC cells survive. Because hepatic sinusoidal endothelial cells kill tumor cells in vitro by producing nitric oxide, superoxide anion, and other reactive oxygen and nitrogen species, our purpose was to determine whether reoxygenation of ischemic hepatic cultures in vitro forms toxic oxygen and nitrogen radicals that kill weakly but not highly metastatic CRC cells. CRC cells (10(7)) were labeled with rhodamine-dextran and calcein AM, cultured with cells from one mouse liver in a rotating suspension culture system for up to 24 h, and the metabolic activity of the CRC cells was determined. Liver fragments oxygenated normally before harvest were not toxic to either CRC cell line, but coculture with liver made ischemic by a 3-min ligation of the portal vein and hepatic artery in vivo before harvest and then cultured in oxygenated medium killed 50-70% of weakly metastatic clone A and MIP-101 cells at 24 h but <15% of highly metastatic CX-1 cells. Inhibition of nitric oxide synthase, addition of exogenous superoxide dismutase, but not catalase or hypoxia, during coculture blocked the killing of weakly metastatic CRC cells. Thus, reoxygenation of hepatic parenchymal and nonparenchymal cells after ischemia may form toxic species that eliminate weakly metastatic CRCs within 24 h of their arrest in the liver.

Speckle photography using optically addressed multiple quantum well spatial light modulators.

We demonstrate speckle photography using an optically addressed multiple quantum well spatial light modulator. An optical Fourier transform is used to allow real-time displacement measurements.

Pelvic-peritoneal tuberculosis simulating ovarian carcinoma: report of three cases with elevation of the CA 125.

We report three cases of women with abdominal pathology in which an elevated serum CA 125 tumor marker could have led to an erroneous diagnosis of ovarian carcinoma. However, after peritoneal biopsies were taken, tuberculosis was diagnosed. Furthermore, specific tuberculostatic treatment normalized serum CA 125 levels.

Generation of high-contrast narrow-band subpicosecond correlations from broadband stochastic fields.

We demonstrate that two broadband stochastic fields generated by use of either parametric frequency conversion or stimulated Raman scattering can be mixed in a nonlinear crystal to produce an output spectrum with a pronounced narrow-band feature. This narrow-band feature, which we show is due to the phase-correlated nature of the beams, is present when the two broadband beams are delayed less than a coherence length relative to each other. We apply this technique to a novel measurement of the field cross-correlation function between two broadband stochastic fields with different center frequencies.