[Inhibition of telomerase activity by ribozyme targeted to human telomerase transcriptase]

Human telomerase reverse transcriptase (hTERT) is the catalytic subunit and the key factor which controls the telomerase activity,so it is the best choice to inhibit telomerase through controling hTERT expression.In this work,a hammer head ribozyme directed against the hTERT mRNA (hTERTRZ) was designed and synthesized to serve as a telomerase inhibitor. In order to test its in vitro cleavage activity, two in vitro transcription plasmids containing hTERTRZ and hTERT gene respectively were constructed. Ribozyme RNA and DIG-labeled-hTERT were synthesized by in vitro transcription. In vitro cleavage reactions were carried out by mixing the hTERTRZ with DIG-labeled-hTERT under different reaction conditions, and cleavage bands were detected by digoxin chemiluminescent assay. hTERTRZ showed a specific cleavage activity against the hTERT used as template. To investigate its in vivo effect of telomerase inhibition in tumor cells, a eukaryotic expression plasmid containing the hTERT ribozyme gene was introduced into HeLa cells and hepatoma cells by using LipofectAMINE. In the transfectants, the level of intact hTERT mRNA and the telomerase activity were clearly reduced, and the telomere length of these clones was apparently shortened at the beginning period, then kept a fixed value without further shortening. All the transfectants with ribozyme grew clearly more slowly than the parental cell line. The doubling time of the tansfectants prolonged compared to the negative control, but no apparent apoptosis was shown even at their 37th passage. These findings suggest the potential application of this ribozyme as a new theraputic agent directed against immortalized cancer cells.

Control of the shape of a thrombus-neointima-like structure by blood shear stress

Fluid mechanical factors are thought to influence vascular morphogenesis. Here we show how blood shear stress regulates the shape of a thrombus-neointima-like tissue on a polymer micro-cylinder implanted in the center of the rat vena cava with the micro-cylinder perpendicular to blood flow. In this model, the micro-cylinder is exposed to a laminarflow with a known shear stress field in the leading region and a vortexflow in the trailing region. At 1, 5, 10, 20, and 30 days after implantation, it was found that the micro-cylinder was encapsulated by a thrombus-neointima-like tissue with a streamlined body profile. The highest growth rate of the thrombus-neointima-like tissue was found along the trailing and leading stagnation edges of the micro-cylinder. Blood shear stress in the laminar flow region was inversely correlated with the rate of thrombus formation and cell proliferation, and the percentage of smooth muscle a actin-positive cells. These biological changes were also found in the trailing vortex flow region, which was associated with lowered shear stress. These results suggest that blood shear stress regulates the rate of thrombus and neointimal formation and, thus, influences the shape of the thrombus-neointima-like structure in the present model.

Identification of biochemical pathways for the metabolism of oxidized low-density lipoprotein derived aldehyde-4-hydroxy trans-2-nonenal in vascular smooth muscle cells

Oxidation of low-density lipoproteins (LDL) generates high concentrations of unsaturated aldehydes, such as 4-hydroxy trans-2-nonenal (HNE). These aldehydes are mitogenic to vascular smooth muscle cells and sustain a vascular inflammation. Nevertheless, the processes that mediate and regulate the vascular metabolism of these aldehydes have not been examined. In this communication, we report the identification of the major metabolic pathways and products of [(3)H]-HNE in rat aortic smooth muscle cells in culture. High-performance liquid chromatography separation of the radioactivity recovered from these cells revealed that a large (60-65%) proportion of the metabolism was linked to glutathione (GSH). Electrospray mass spectrometry showed that glutathionyl-1,4 dihydroxynonene (GS-DHN) was the major metabolite of HNE in these cells. The formation of GS-DHN appears to be due aldose reductase (AR)-catalyzed reduction of glutathionyl 4-hydroxynonanal (GS-HNE), since inhibitors of AR (tolrestat or sorbinil) prevented GS-DHN formation, and increased the fraction of the glutathione conjugate remaining as GS-HNE. Gas chromatography-chemical ionization mass spectroscopy of the metabolites identified a subsidiary route of HNE metabolism leading to the formation of 4-hydroxynonanoic acid (HNA). Oxidation to HNA accounted for 25-30% of HNE metabolism. The formation of HNA was inhibited by cyanamide, indicating that the acid is derived from an aldehyde dehydrogenase (ALDH)-catalyzed pathway. The overall rate of HNE metabolism was insensitive to inhibition of AR or ALDH, although inhibition of HNA formation by cyanamide led to a corresponding increase in the fraction of HNE metabolized by the GSH-linked pathway, indicating that ALDH-catalyzed oxidation competes with glutathione conjugation. These metabolic pathways may be the key regulators of the vascular effects of HNE and oxidized LDL.

Binding of pyridine nucleotide coenzymes to the beta-subunit of the voltage-sensitive K+ channel

The beta-subunit of the voltage-sensitive K(+) (K(v)) channels belongs to the aldo-keto reductase superfamily, and the crystal structure of K(v)beta2 shows NADP bound in its active site. Here we report that K(v)beta2 displays a high affinity for NADPH (K(d) = 0.1 micrometer) and NADP(+) (K(d) = 0.3 micrometer), as determined by fluorometric titrations of the recombinant protein. The K(v)beta2 also bound NAD(H) but with 10-fold lower affinity. The site-directed mutants R264E and N333W did not bind NADPH, whereas, the K(d)(NADPH) of Q214R was 10-fold greater than the wild-type protein. The K(d)(NADPH) was unaffected by the R189M, W243Y, W243A, or Y255F mutation. The tetrameric structure of the wild-type protein was retained by the R264E mutant, indicating that NADPH binding is not a prerequisite for multimer formation. A C248S mutation caused a 5-fold decrease in K(d)(NADPH), shifted the pK(a) of K(d)(NADPH) from 6.9 to 7.4, and decreased the ionic strength dependence of NADPH binding. These results indicate that Arg-264 and Asn-333 are critical for coenzyme binding, which is regulated in part by Cys-248. The binding of both NADP(H) and NAD(H) to the protein suggests that several types of K(v)beta2-nucleotide complexes may be formed in vivo.

Growth and arginine metabolism of the wine lactic acid bacteria Lactobacillus buchneri and Oenococcus oeni at different pH values and arginine concentrations

During malolactic fermentation (MLF) in grape must and wine, heterofermentative lactic acid bacteria may degrade arginine, leading to the formation of ammonia and citrulline, among other substances. This is of concern because ammonia increases the pH and thus the risk of growth by spoilage bacteria, and citrulline is a precursor to the formation of carcinogenic ethyl carbamate (EC). Arginine metabolism and growth of Lactobacillus buchneri CUC-3 and Oenococcus oeni strains MCW and Lo111 in wine were investigated. In contrast to L. buchneri CUC-3, both oenococci required a higher minimum pH for arginine degradation, and arginine utilization was delayed relative to the degradation of malic acid, the main aim of MLF. This allows the control of pH increase and citrulline formation from arginine metabolism by carrying out MLF with pure oenococcal cultures and inhibiting cell metabolism after malic acid depletion. MLF by arginine-degrading lactobacilli should be discouraged because arginine degradation may lead to the enhanced formation of acids from sugar degradation. A linear relationship was found between arginine degradation and citrulline excretion rates. From this data, strain-specific arginine-to-citrulline conversion ratios were calculated that ranged between 2.2 and 3.9% (wt/wt), and these ratios can be used to estimate the contribution of citrulline to the EC precursor pool from a given amount of initial arginine. Increasing arginine concentrations led to higher rates of growth of L. buchneri CUC-3 but did not increase the growth yield of either oenococcus. These results suggest the use of non-arginine-degrading oenococci for inducing MLF.

Role of blood shear stress in the regulation of vascular smooth muscle cell migration

Smooth muscle cell (SMC) migration from the media to the intima of blood vessels contributes to neointimal formation and atherogenesis. Here, we demonstrate how blood shear stress regulates vascular SMC migration in the encapsulating tissue of a micro-cylinder implanted in the center of the rat vena cava with the micro-cylinder perpendicular to blood flow. In this model, the micro-cylinder was exposed to a laminar flow with a known shear stress field in the leading region and a vortex flow in the trailing region. After surgery, the micro-cylinder was encapsulated by a thrombus-like tissue within one day, followed by SMC migration from the vena cava to the encapsulating tissue from day 3 to 20. SMC migration was time-dependent with a peak migration speed at day 5. At each given time (excluding day 1), blood shear stress exerts an inhibitory effect on SMC migration with significantly suppressed SMC migration in the laminar flow region than in the stagnation, separation, and vortex flow regions. SMCs were relatively parallel to the shear stress direction in high shear stress regions, whereas perpendicular to the shear stress direction in low shear stress regions. These results suggest that blood shear stress plays a role in regulating SMC migration and orientation in this model.

Role of tensile stress and strain in the induction of cell death in experimental vein grafts

Tensile stress and strain are known to induce vascular cell proliferation, a process that is physiologically counterbalanced by cell death. Here we investigate whether tensile stress and strain regulate vascular-cell death by using an end-to-end anastomosed rat vein graft model. In such a model, the circumferential tensile stress in the graft wall was increased by approximately 140 times immediately after surgery compared with that in the venous wall. This change was associated with an increase in the percentage of TUNEL-positive cells at 1, 6, 24, 120, 240, and 720h with two distinct peaks at 1 and 24h (10.1+/-3.5 and 14.4+/-3.2%, respectively) compared with that in control jugular veins (0.4+/-0.5 and 0.5+/-0.5% at 1 and 24h, respectively). When tensile stress and strain in the vein graft wall were reduced by using a biomechanical engineering approach, the rate of cell death was reduced significantly (3.6+/-1.1 and 1.6+/-0.5% at 1 and 24h, respectively). Furthermore, DEVD-CHO, a tetrapeptide aldehyde that inhibits the activity of caspase 3, significantly suppressed this event. These results suggest that a step increase in tensile stress and strain in experimental vein grafts induces rapid cell death, which is possibly mediated by cell death signaling mechanisms.

Binding of pyridine coenzymes to the beta-subunit of the voltage sensitive potassium channels

The beta-subunit of the voltage-sensitive K(+) channels shares 15-30% amino acid identity with the sequences of aldo-keto reductases (AKR) genes. However, the AKR properties of the protein remain unknown. To begin to understand its oxidoreductase properties, we examine the pyridine coenzyme binding activity of the protein in vitro. The cDNA of K(v)beta2.1 from rat brain was subcloned into a prokaryotic expression vector and overexpressed in Escherichia coli. The purified protein was tetrameric in solution as determined by size exclusion chromatography. The protein displayed high affinity binding to NADPH as determined by fluorometric titration. The K(D) values for NADPH of the full-length wild-type protein and the N-terminus deleted protein were 0.1+/-0.007 and 0.05+/-0.006 M, respectively - indicating that the cofactor binding domain is restricted to the C-terminus, and is not drastically affected by the absence of the N-terminus amino acids, which form the ball and chain regulating voltage-dependent inactivation of the alpha-subunit. The protein displayed poor affinity for other coenzymes and the corresponding values of the K(D) for NADH and NAD were between 1-3 microM whereas the K(D) for FAD was >10 microM. However, relatively high affinity binding was observed with 3-acetyl pyridine NADP, indicating selective recognition of the 2' phosphate at the binding site. The selectivity of K(v)beta2.1 for NADPH over NADP may be significant in regulating the K(+) channels as a function of the cellular redox state.

Involvement of aldose reductase in the metabolism of atherogenic aldehydes

Phospholipid peroxidation generates a variety of aldehydes, which includes free saturated and unsaturated aldehydes, and aldehydes that remain esterified to the phosphoglyceride backbone - the so-called 'core' aldehydes. However, little is known in regarding the vascular metabolism of these aldehydes. To identify biochemical pathways that metabolize free aldehydes, we examined the metabolism of 4-hydroxy-trans-2-nonenal in human aortic endothelial cells. Incubation of these cells with [3H]-HNE led to the generation of four main metabolites, i.e. glutathionyl HNE (GS-HNE), glutathionyl dihydroxynonene (GS-DHN), DHN and 4-hydroxynonanoic acid (HNA), which accounted for 5, 50, 6, and 23% of the total HNE metabolized. The conversion of GS-HNE to GS-DHN was inhibited by tolrestat, indicating that it is catalyzed by aldose reductase (AR). The AR was also found to be an efficient catalyst for the reduction of the core aldehyde - 1-palmitoyl-2- (5-oxovaleroyl)-sn-glycero-3-phosphorylcholine, which is generated in minimally modified low-density lipoprotein, and activates the endothelium to bind monocytes. As determined by electrospray mass spectrometry, reduction of POVPC (m/z=594) by AR led to the formation of 1-palmitoyl-2- (5)-hydrovaleryl-sn-glycero-3-phosphorylcholine (PHVPC; m/z=596). These observations suggest that due to its ability to catalyze the reduction of lipid-derived aldehydes AR may be involved in preventing inflammation and diminishing oxidative stress during the early phases of atherogenesis.

Acetaldehyde metabolism by wine lactic acid bacteria

Acetaldehyde is a volatile flavor compound present in many fermented foods and is important in the production of red and white wines. Nine strains of the genera Lactobacillus and Oenococcus were able to metabolize acetaldehyde in a resting cell system, whereas two Pediococcus strains were not. Acetic acid and ethanol were produced from its degradation. A Lactobacillus and an Oenococcus were able to degrade SO(2)-bound acetaldehyde, as well. A coincubation of resting cells of Saccharomyces bayanus Première Cuvée and Oenococcus oeni Lo111 showed that strain Lo111 metabolized acetaldehyde produced by the yeast. The ability of malolactic bacteria to degrade free and SO(2)-bound acetaldehyde has implications for sensory and color qualities and the use of SO(2) in wine.

Kinetics of the arginine metabolism of malolactic wine lactic acid bacteria Lactobacillus buchneri CUC-3 and Oenococcus oeni Lo111

The excretion of citrulline, a precursor of carcinogenic ethyl carbamate, formed from arginine degradation by malolactic bacteria in wine is of toxicological concern. The arginine metabolism of resting cells of Lactobacillus buchneri CUC-3 and Oenococcus oeni Lo1l1 was examined. The citrulline excretion rate was found to be linearly correlated to the arginine degradation rate. It was possible to calculate an arginine to citrulline conversion ratio which could be used to predict the amount of citrulline expected after the degradation of a known quantity of arginine. The conversion ratios determined in this study were similar to data calculated from other authors for fermentations in wine and ranged between 4.0% and 7.7%. Ribose, fructose and glucose inhibited the degradation of arginine in Lact. buchneri CUC-3, and inhibition of arginine degradation by glucose correlated with higher arginine to citrulline conversion ratios. The work presents new results of arginine metabolism in malolactic bacteria and gives starting points for investigations in wine.

Cyclooxygenase-2 mediates the cardioprotective effects of the late phase of ischemic preconditioning in conscious rabbits

We examined the role of cyclooxygenase-2 (COX-2) in the late phase of ischemic preconditioning (PC). A total of 176 conscious rabbits were used. Ischemic PC (six cycles of 4-min coronary occlusions/4-min reperfusions) resulted in a rapid increase in myocardial COX-2 mRNA levels (+231 +/- 64% at 1 h; RNase protection assay) followed 24 h later by an increase in COX-2 protein expression (+216 +/- 79%; Western blotting) and in the myocardial content of prostaglandin (PG)E(2) and 6-keto-PGF(1alpha) (+250 +/- 85% and +259 +/- 107%, respectively; enzyme immunoassay). Administration of two unrelated COX-2 selective inhibitors (NS-398 and celecoxib) 24 h after ischemic PC abolished the ischemic PC-induced increase in tissue levels of PGE(2) and 6-keto-PGF(1alpha). The same doses of NS-398 and celecoxib, given 24 h after ischemic PC, completely blocked the cardioprotective effects of late PC against both myocardial stunning and myocardial infarction, indicating that COX-2 activity is necessary for this phenomenon to occur. Neither NS-398 nor celecoxib lowered PGE(2) or 6-keto-PGF(1alpha) levels in the nonischemic region of preconditioned rabbits, indicating that constitutive COX-1 activity was unaffected. Taken together, these results demonstrate that, in conscious rabbits, up-regulation of COX-2 plays an essential role in the cardioprotection afforded by the late phase of ischemic PC. Therefore, this study identifies COX-2 as a cardioprotective protein. The analysis of arachidonic acid metabolites strongly points to PGE(2) and/or PGI(2) as the likely effectors of COX-2-dependent protection. The recognition that COX-2 mediates the antistunning and antiinfarct effects of late PC impels a reassessment of current views regarding this enzyme, which is generally regarded as detrimental.

[Determination of flavonoids in Ginkgo biloba L. leaves from different producing areas]

OBJECTIVE

To compare the contents of flavonoids in the leaves of Ginkgo biloba gathered from 35 producing areas.

METHODS

Separating and determining 3 flavonoid aglycones, quercetin, kaempferol and isorhamnetin, by high performance liquid chromatography, and there by calculating the total contents of flavonoids.

RESULTS

The contents of flavonoids in the leaves of G. biloba gathered from different producing areas are different, but in those gathered from Pizhou, Zheng'an Xing'an, Anlu, etc. appear higher.

Involvement of aldose reductase in vascular smooth muscle cell growth and lesion formation after arterial injury

Abnormal proliferation of vascular smooth muscle cells (VSMCs) is an important feature of atherosclerosis, restenosis, and hypertension. Although multiple mediators of VSMC growth have been identified, few effective pharmacological tools have been developed to limit such growth. Recent evidence indicating an important role for oxidative stress in cell growth led us to investigate the potential role of aldose reductase (AR) in the proliferation of VSMCs. Because AR catalyzes the reduction of mitogenic aldehydes derived from lipid peroxidation, we hypothesized that it might be a potential regulator of redox changes that accompany VSMC growth. Herein we report several lines of evidence suggesting that AR facilitates/mediates VSMC growth. Stimulation of human aortic SMCs in culture with mitogenic concentrations of serum, thrombin, basic fibroblast growth factor, and the lipid peroxidation product 4-hydroxy-trans-2-nonenal (HNE) led to a 2- to 4-fold increase in the steady-state levels of AR mRNA, a 4- to 7-fold increase in AR protein, and a 2- to 3-fold increase in its catalytic activity. Inhibition of the enzyme by sorbinil or tolrestat diminished mitogen-induced DNA synthesis and cell proliferation. In parallel experiments, the extent of reduction of the glutathione conjugate of HNE to glutathionyl-1,4-dihydroxynonene in HNE-exposed VSMCs was decreased by serum starvation or sorbinil. Immunohistochemical staining of cross sections from balloon-injured rat carotid arteries showed increased expression of AR protein associated with the neointima. The media of injured or uninjured arteries demonstrated no significant staining. Compared with untreated animals, rats fed sorbinil (40 mg. kg(-1). d(-1)) displayed a 51% and a 58% reduction in the ratio of neointima to the media at 10 and 21 days, respectively, after balloon injury. Taken together, these findings suggest that AR is upregulated during growth and that this upregulation facilitates growth by enhancing the metabolism of secondary products of reactive oxygen species.

Synaptic activity at calcium-permeable AMPA receptors induces a switch in receptor subtype

Activity-dependent change in the efficacy of transmission is a basic feature of many excitatory synapses in the central nervous system. The best understood postsynaptic modification involves a change in responsiveness of AMPAR (alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptor)-mediated currents following activation of NMDA (N-methyl-D-aspartate) receptors or Ca2+-permeable AMPARs. This process is thought to involve alteration in the number and phosphorylation state of postsynaptic AMPARs. Here we describe a new form of synaptic plasticity--a rapid and lasting change in the subunit composition and Ca2+ permeability of AMPARs at cerebellar stellate cell synapses following synaptic activity. AMPARs lacking the edited GluR2 subunit not only exhibit high Ca2+ permeability but also are blocked by intracellular polyamines. These properties have allowed us to follow directly the involvement of GluR2 subunits in synaptic transmission. Repetitive synaptic activation of Ca2+-permeable AMPARs causes a rapid reduction in Ca2+ permeability and a change in the amplitude of excitatory postsynaptic currents, owing to the incorporation of GluR2-containing AMPARs. Our experiments show that activity-induced Ca2+ influx through GluR2-lacking AMPARs controls the targeting of GluR2-containing AMPARs, implying the presence of a self-regulating mechanism.

[Derivative-ratio derivative spectrum method for determining nitrate and nitrite radicals (NO3- and NO2-) in environmental water]

A derivative-ratio derivative spectrum method was devised for resolving the interference of two components in a two-component mixture measured in derivative spectrum method. The ratio derivative spectrum was obtained from the derivative absorption spectrum of the mixture divided by a derivative absorption spectrum of one of the components. The derivative of ratio derivative spectrum against wavelength resulted in the derivative-ratio derivative spectrum that was determined by the concentration of one component of the mixture. The results suggest that this method is better than ratio derivative spectrum method and it can be applied for determining nitrate and nitrite (NO3- and NO2-) in environment water samples. Being simple and stable, it can eliminate the influence of the interfering materials, giving a recovery rate of more than 96.7%.

Prevention of mechanical stretch-induced endothelial and smooth muscle cell injury in experimental vein grafts

Vein grafts are subject to increased tensile stress due to exposure to arterial blood pressure, which has been hypothesized to induce endothelial cell (EC) and smooth muscle cell (SMC) injury. This study was designed to verify this hypothesis and to develop a tissue engineering approach that can be used to prevent these pathological events. Two experimental models were created in rats to achieve these goals: (1) a nonengineered vein graft with increased tensile stress, which was created by grafting a jugular vein into the abdominal aorta using a conventional end-to-end anastomotic technique; and (2) an engineered vein graft with reduced tensile stress, which was created by restricting a vein graft into a cylindrical sheath constructed using a polytetrafluoroethylene membrane. The integrity of ECs in these models was examined by using a silver nitrate staining method, and the integrity of SMCs was assessed by using a fluorescein phalloidin-labeling technique. It was found that nonengineered vein grafts were associated with early EC denudation with a change in EC coverage from 100 percent in normal jugular veins to 36 +/- 10, 28 +/- 12, 18 +/- 9, 44 +/- 15, 80 +/- 13, and 97 +/- 6 percent at 1 and 6 hours and 1, 5, 10, and 30 days, respectively. Similarly, rapid SMC actin filament degradation was found during the early period with a change in SMC coverage from approximately 94 percent in normal jugular veins to 80 +/- 10, 41 +/- 17, 25 +/- 9, 51 +/- 15, 79 +/- 15, 98 +/- 2 percent at 1 and 6 hours and 1, 5, 10, and 30 days, respectively, in nonengineered vein grafts. In engineered vein grafts with reduced tensile stress, EC denudation and SMC actin filament degradation were prevented significantly. These results suggested that mechanical stretch due to increased tensile stress contributed to EC and SMC injury in experimental vein grafts, and these pathological events could be partially prevented when tensile stress was reduced by using a biomechanical engineering approach.

Biomechanical basis of vascular tissue engineering

Blood vessels develop under the influence of mechanical stresses and strains and remodel in response to alterations in these factors. It has long been hypothesized that mechanical stresses and strains contribute to the development of vascular diseases such as atherosclerosis and hypertrophy. A large number of studies have been conducted to verify this hypothesis and have demonstrated that increased tensile stress and strain due to hypertension may induce and/or facilitate vascular hypertrophy, and oscillatory low fluid shear stress and/or altered shear gradients due to eddy blood flow may initiate and/or promote focal atherosclerosis and intimal hyperplasia. A variety of cellular components, including growth-related factors, cell membrane proteins and lipids, intracellular signaling molecules and transcriptional factors, and immediate early genes and mitogenic genes, have been shown to mediate these mechanical stress-related pathological processes. These discoveries suggest that a modulation of tensile and fluid shear stresses and strains, if possible, may prevent mechanical stress-induced pathological changes in blood vessels and thus constitute a foundation for the development of vascular engineering approaches. Recent studies have demonstrated by using an experimental vein graft model that biomechanical engineering approaches can be used to reduce tensile stress and strain due to exposure to arterial blood pressure and to prevent eddy blood flow in vein grafts. Such engineering modulations significantly reduced the rate of focal intimal hyperplasia and medial and adventitial hypertrophy in vein grafts. These preliminary studies have provided convincing evidence for further development of vascular biomechanical engineering approaches. In this article, the background, principles, clinical potentials, as well as the limitations of vascular biomechanical engineering are discussed.

Focal expression of angiotensin II type 1 receptor and smooth muscle cell proliferation in the neointima of experimental vein grafts: relation to eddy blood flow

Eddy flow has been shown to promote focal smooth muscle cell (SMC) proliferation and neointimal formation in experimental vein grafts. This study focuses on whether the angiotensin II type 1 (AT(1)) receptor mediates these events. Experimental vein grafts with and without eddy flow were created in the rat. Losartan was used to assess the influence of the AT(1) receptor on SMC proliferation. In vein grafts with eddy flow, apparent focal expression of AT(1) mRNA and protein was found in the leading region of the proximal focal neointima, where eddy flow occurred, but not in the trailing region, where eddy flow diminished, at days 5, 10, 20, and 30. The rate of SMC proliferation in the leading region (10.9+/-1.4%, 19.5+/-2.2%, 12.2+/-2.0%, and 6.9+/-1.3% at these times, respectively) was significantly higher than that in the trailing region (9.5+/-1.8%, 15.3+/-2.0%, 8.2+/-1.9%, and 3.2+/-0.7%) in these vein grafts. When eddy flow was prevented in engineered vein grafts, no apparent location difference was found in the distribution of AT(1) receptor mRNA and protein in the neointima, and the rate of SMC proliferation (5.3+/-1.0%, 5.8+/-0.9%, 3.4+/-1.0%, and 3.7+/-0.9% at days 5, 10, 20, and 30, respectively) was reduced significantly. In vein grafts with losartan, the rate of SMC proliferation in the leading region of the neointima (9.4+/-1.8%, 10.1+/-1.3%, 8.3+/-0.9%, and 4.2+/-0. 5% at days 5, 10, 20, and 30, respectively) was significantly lower than that in vein grafts without losartan. These results suggested that eddy flow upregulated the AT(1) receptor, which in turn mediated focal SMC proliferation in the neointima of experimental vein grafts.

Partial prevention of monocyte and granulocyte activation in experimental vein grafts by using a biomechanical engineering approach

Leukocytes interact with endothelial cells and contribute to the development of vascular diseases such as thrombosis and atherosclerosis. These processes are possibly influenced by mechanical factors. This study focused on the role of mechanical stretch in the activation of monocytes and granulocytes in experimental vein grafts. Two models were created by using rats: a nonengineered vein graft with increased tensile stress, which was created by grafting a jugular vein into the abdominal aorta, and an engineered vein graft with reduced tensile stress, which was created by restricting the vein graft into a cylindrical sheath constructed by using fixative-treated intestinal tissue. The density of activated monocytes and granulocytes, which attached to the endothelium, and the distribution of the intercellular adhesion molecule (ICAM)-1 in endothelial cells were examined using immunohistological assays. It was found that, in nonengineered vein grafts, the density of activated monocytes and granulocytes increased significantly compared to that in normal jugular veins at day 1, 5, 10 and 20. At each observation time, the cell density in the proximal region of the nonengineered vein grafts was significantly higher than that in the middle and distal regions, and the cell density in the distal region was significantly higher than that in the middle region. These changes were associated with ICAM-1 clustering at day 1 and 5 and focal ICAM-1 un-regulation at day 10 and 20. In engineered vein grafts, the density of activated monocytes and granulocytes decreased significantly compared to that in nonengineered vein grafts at all observation times, although it was significantly higher than that in normal jugular veins. At each observation time, the cell density in the proximal and distal regions was significantly higher than that in the middle region, but no significant difference was found between the proximal and distal regions. ICAM-1 clustering along endothelial cell borders was found at day 1 and 5, but no apparent focal ICAM-1 up-regulation was found at day 10 and 20. These results suggested that mechanical stretch due to exposure to increased tensile stress contributed to the activation of monocytes and granulocytes in experimental vein grafts, and this event could be partially prevented by reducing tensile stress using a biomechanical engineering approach.

Reduction of end-stage malignant glioma by injection with autologous cytotoxic T lymphocytes

Autologous cytotoxic T lymphocytes (CTL) against primary-cultured malignant gliomas were generated from peripheral blood mononuclear cells in vitro in 4 patients. Activities of the CTL were highly specific to the corresponding autologous glioma and were inhibited, in one patient, with antibodies against CD3, CD8 and MHC-class I molecules. When the CTL were injected 3 times into the primary-tumor-resected cavity via an Ommaya tube, reduction of the recurrent tumors with magnetic resonance imaging (MRI)-measured volumes exceeding 45 cm3 was observed in 3 patients. In a patient with glioblastoma multiforme (GBM), the tumor volume (estimated, 130 cm3) was rapidly reduced to 1/3, although re-recurrence of the tumor followed 40 days later. A slight but distinct rapid reduction of the tumor volume was observed in another GBM patient and in an anaplastic astrocytoma patient; essentially no change was observed in a further GBM patient. These results suggest that adoptive immunotherapy with autologous CTL will be clinically effective against end-stage malignant gliomas.

Autologous high-killing cytotoxic T lymphocytes against human lung cancer are induced using interleukin (IL)-1beta, IL-2, IL-4, and IL-6: possible involvement of dendritic cells

Although CTLs bear main immune responses in human tumors, stable CTL clones against human lung cancer have rarely been generated. Our previous study demonstrated efficient autologous CTL induction in human gastric cancer and glioblastoma by cytokine combination of interleukin (IL)-1beta (167 IU/ml), IL-2 (67 IU/ml), IL-4 (67 IU/ml), and IL-6 (134 IU/ml). In this study, we demonstrated successful induction of autologous stable CTLs in five of six patients with lung adenocarcinoma from mixed-lymphocyte tumor culture using this cytokine combination. All CTLs revealed potent and specific killing activity against autologous target cells (over 75% in CD8+ CTLs and over 50% in CD4+ CTLs at an E:T ratio of 10 for 24 h). Using a series of antibodies, CD8+ CTLs showed to recognize tumor-specific antigens of lung cancer cells through HLA class I. In the separate experiments, failure of CTL induction from monocyte-depleted peripheral blood mononuclear cells and appearance of cells with characteristics of dendritic cells from adherent peripheral blood mononuclear cells in the culture of the same concentration of IL-1beta, IL-4, and IL-6 indicated that CTLs can be efficiently generated by this cytokine combination via possible dendritic cell induction. This is the first study of an efficient and reproducible in vitro CTL induction against human lung cancer.

T-cell stimulation through the T-cell receptor/CD3 complex regulates CD2 lateral mobility by a calcium/calmodulin-dependent mechanism

T lymphocyte activation through the T cell receptor (TCR)/CD3 complex alters the avidity of the cell surface adhesion receptor CD2 for its ligand CD58. Based on the observations that activation-associated increases in intracellular [Ca2+] ([Ca2+]i) strengthen interactions between T cells and antigen-presenting cells, and that the lateral mobility of cell surface adhesion receptors is an important regulator of cellular adhesion strength, we postulated that [Ca2+]i controls CD2 lateral mobility at the T cell surface. Human Jurkat T leukemia cells were stimulated by antibody-mediated cross-linking of the TCR/CD3 complex. CD2 was labeled with a fluorescently conjugated monoclonal antibody. Quantitative fluorescence microscopy techniques were used to measure [Ca2+]i and CD2 lateral mobility. Cross-linking of the TCR/CD3 complex caused an immediate increase in [Ca2+]i and, 10-20 min later, a decrease in the fractional mobility of CD2 from the control value of 68 +/- 1% to 45 +/- 2% (mean +/- SEM). One to two hours after cell stimulation the fractional mobility spontaneously returned to the control level. Under these and other treatment conditions, the fraction of cells with significantly elevated [Ca2+]i was highly correlated with the fraction of cells manifesting significantly reduced CD2 mobility. Pretreatment of cells with a calmodulin inhibitor or a calmodulin-dependent kinase inhibitor prevented Ca2+-mediated CD2 immobilization, and pretreatment of cells with a calcineurin phosphatase inhibitor prevented the spontaneous reversal of CD2 immobilization. These data suggest that T cell activation through the TCR/CD3 complex controls CD2 lateral mobility by a Ca2+/calmodulin-dependent mechanism, and that this mechanism may involve regulated phosphorylation and dephosphorylation of CD2 or a closely associated protein.

Investigation of a series of synthetic cationic porphyrins using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) was used to study a series of synthetic cationic porphyrins as the perchlorate and bromide salts. This work presents the analytical results for the porphyrins obtained using 2, 5-dihydroxybenzoic acid (DHB) and 1,8,9-anthratriol as matrices. The selective use of matrix affects ion formation from these porphyrins. By using DHB as the matrix, we not only observed [M - nClO(4)](+) (n = 1-4) ions, but also obtained [2M - nClO(4)](+) (n = 2-7) ions from the synthetic cationic porphyrins. The space volume of the side chains (R groups) and the nature of the anions (Br(-) or ClO(4)(-)) affected the relative importance of monomeric and dimeric ions of the porphyrin. The possible mechanisms of desorption and ionization of these cationic porphyrins were also considered in this study. MALDI-TOFMS proved to be a very useful method for obtaining structural information on these synthetic cationic porphyrins. Copyright 1999 John Wiley & Sons, Ltd.

High rate of induction of human autologous cytotoxic T lymphocytes against renal carcinoma cells cultured with an interleukin cocktail

A high rate of induction (9 of 10 cases) of human autologous cytotoxic T lymphocytes (CTL) was achieved in vitro from peripheral blood mononuclear cells of renal carcinoma patients by applying an interleukin (IL)-cocktail consisting of IL-1, -2, -4, and -6. The CTL specifically lysed their own target carcinoma cells within 24 h but did not kill neighboring autologous normal kidney cells or allogeneic renal cancer cell lines. In the case of TUHR4TKB, for which autologous CTL were not induced, no expression of MHC class-I molecules was observed on the surface of these carcinoma cells, although they were sensitive to autologous natural killer cells. The results imply that adoptive immunotherapy for metastasized renal carcinoma will be feasible with autologous CTL in combination with natural killer cells.