Binding of endostatin to human ovarian cancer cells inhibits cell attachment

Endostatin, a C-terminal fragment of collagen type XVIII, is one of the well-characterized endogenous inhibitors of angiogenesis. Endostatin is known to bind integrin alpha(5)beta(1), which is upregulated on tumor endothelium. Most of the ovarian cancer cells express significant amounts of alpha(5)beta(1) integrin, which is important for ovarian cancer cells to attach to the peritoneal wall. Therefore we investigated whether endostatin could directly bind ovarian cancer cells and inhibit tumor cell attachment to extracellular matrix. Binding of endostatin to ovarian cancer cells was characterized by preincubation with function blocking antibodies to integrin subunits. These studies showed that ovarian cancer cell attachment to fibronectin-coated wells can be inhibited by alpha(5)beta(1) integrin specific antibodies as well as endostatin. Downregulation of integrin alpha(5) and beta(1) by siRNA abrogated the binding of OVCAR5 and human umbilical vein endothelial cell to endostatin. Although endostatin treatment did not affect ovarian cancer cell migration, treated cells failed to attach mouse peritoneal wall preparations. These studies suggest an extra-antiangiogenic role for endostatin, which can be used prevent peritoneal attachment and dissemination of ovarian cancer cells.

Phosphodiesterase-5 Inhibitor in Eisenmenger Syndrome

Background— Phosphodiesterase-5 inhibitors produce a significant decrease in pulmonary vascular resistance in patients with idiopathic pulmonary arterial hypertension. We studied the effects of tadalafil, a phosphodiesterase-5 inhibitor, on short-term hemodynamics, tolerability, and efficacy over a 12-week period in patients of Eisenmenger syndrome having a pulmonary vascular pathology similar to idiopathic pulmonary arterial hypertension.

Methods and Results— Sixteen symptomatic Eisenmenger syndrome patients (mean age, 25±8.9 years) were assessed hemodynamically at baseline and 90 minutes after a single dose of tadalafil (1 mg/kg body weight up to a maximum of 40 mg). The same dose was then continued daily for 12 weeks, and the patients were restudied. There was a significant decrease in mean pulmonary vascular resistance immediately (24.75±8.49 to 19.22±8.23 Woods units; P <0.005) and at 12 weeks (19.22±8.23 to 17.02±6.19 Woods units; P =0.03 versus 90 minutes). Thirteen of 16 patients (81.25%) showed a ≥20% decrease in pulmonary vascular resistance and were defined as responders. The mean systemic oxygen saturation improved significantly both immediately (84.34±5.47% to 87.39±4.34%; P <0.005) and at 12 weeks (87.39±4.34% to 89.16±3.8%; P <0.02 versus 90 minutes) without a significant change in systemic vascular resistance. None of the patients had a fall in systemic arterial pressure, worsening of systemic oxygen saturation, or any adverse reactions to the drug. The mean World Health Organization functional class improved from 2.31±0.47 to 1.25±0.44 ( P <0.0001), and the 6-minute walk distance improved from 344.56±119.06 to 387.56±117.18 m ( P <0.001).

Conclusions— Preliminary evaluation of tadalafil has shown efficacy and safety in selected patients with Eisenmenger syndrome, warranting further investigation in this subgroup of patients.

Biochemistry of homocysteine in health and diseases

The amino acid homocysteine (Hcy), formed from methionine has profound importance in health and diseases. In normal circumstances, it is converted to cysteine and partly remethylated to methionine with the help of vit B12 and folate. However, when normal metabolism is disturbed, due to deficiency of cystathionine-beta-synthase, which requires vit B6 for activation, Hcy is accumulated in the blood with an increase of methionine, resulting into mental retardation (homocystinuria type I). A decrease of cysteine may cause eye diseases, due to decrease in the synthesis of glutathione (antioxidant). In homocystinurias type II, III and IV, there is accumulation of Hcy, but a decrease of methionine, thus, there is no mental retardation. Homocysteinemia is found in Marfan syndrome, some cases of type I diabetes and is also linked to smoking and has genetic basis too. In hyperhomocysteinemias (HHcys), clinical manifestations are mental retardation and seizures (type I only), ectopia lentis, secondary glaucoma, optic atrophy, retinal detachment, skeletal abnormalities, osteoporosis, vascular changes, neurological dysfunction and psychiatric symptoms. Thrombotic and cardiovascular diseases may also be encountered. The harmful effects of homocysteinemias are due to (i) production of oxidants (reactive oxygen species) generated during oxidation of Hcy to homocystine and disulphides in the blood. These could oxidize membrane lipids and proteins. (ii) Hcy can react with proteins with their thiols and form disulphides (thiolation), (iii) it can also be converted to highly reactive thiolactone which could react with the proteins forming -NH-CO- adducts, thus affecting the body proteins and enzymes. Homocystinuria type I is very rare (1 in 12 lakhs only) and is treated with supplementation of vit B6 and cystine. Others are more common and are treated with folate, vit B12 and in selected cases as in methionine synthase deficiency, methionine, avoiding excess. In this review, the role of elevated Hcy levels in cardiovascular, ocular, neurologial and other diseases and the possible therapeutic measures, in addition to the molecular mechanisms involved in deleterious manifestations of homocysteinemia, have been discussed.

Microstructure and rheology of thermoreversible nanoparticle gels

Naïve mode coupling theory is applied to particles interacting with short-range Yukawa attractions. Model results for the location of the gel line and the modulus of the resulting gels are reduced to algebraic equations capturing the effects of the range and strength of attraction. This model is then applied to thermo reversible gels composed of octadecyl silica particles suspended in decalin. The application of the model to the experimental system requires linking the experimental variable controlling strength of attraction, temperature, to the model strength of attraction. With this link, the model predicts temperature and volume fraction dependencies of gelation and modulus with five parameters: particle size, particle volume fraction, overlap volume of surface hairs, and theta temperature. In comparing model predictions with experimental results, we first observe that in these thermal gels there is no evidence of clustering as has been reported in depletion gels. One consequence of this observation is that there are no additional adjustable parameters required to make quantitative comparisons between experimental results and model predictions. Our results indicate that the naïve mode coupling approach taken here in conjunction with a model linking temperature to strength of attraction provides a robust approach for making quantitative predictions of gel mechanical properties. Extension of model predictions to additional experimental systems requires linking experimental variables to the Yukawa strength and range of attraction.

Plasma homocysteine and total thiol content in patients with exudative age-related macular degeneration

PURPOSE

Exudative age-related macular degeneration (ARMD) is one of the debilitating ocular complications, which results in permanent blindness. Elevated homocysteine (Hcys) levels have been associated in the development of several vascular diseases. Vascular and oxidative stress theories have been implicated for the development of choroidal neovascularization in exudative ARMD. The aim of the present study was to investigate the possible role of plasma Hcys and thiol content (tSH) as a risk factor for the development of exudative ARMD.

METHOD

A total of 16 patients with exudative ARMD and 20 age-matched controls were recruited for the study. Plasma Hcys levels were analysed using Reverse Phase High Performance Liquid Chromatography. Plasma glutathione (GSH) content was determined using o-phthalaldehyde (OPA) derivatization and subsequent detection by fluorimeter. Plasma tSH levels were determined by using thiol-specific reagent dithionitrobenzoic acid (DTNB) spectrophotometrically.

RESULTS

Plasma Hcys levels in exudative ARMD were elevated three-fold (18+/-5.0 microM) when compared to healthy controls (6.7+/-1.8 microM). There was a two-fold decrease in the GSH and tSH in exudative ARMD when compared with controls. Negative correlation was observed between diminished tSH and Hcys levels (r=-0.4837, P=0.05). Similarly plasma Hcys levels negatively correlated with GSH content (r=-0.6620, P<0.05).

CONCLUSION

Results from our present study revealed that there is an elevated Hcys level and diminished thiol pool content in exudative ARMD that are significant.

Microscopic dynamics of recovery in sheared depletion gels

We report x-ray photon correlation spectroscopy and diffusing wave spectroscopy studies of depletion gels formed from nanoscale silica colloids in solutions of nonabsorbing polymer following the cessation of shear. The two techniques provide a quantitatively coherent picture of the dynamics as ballistic or convective motion of colloidal clusters whose internal motion is arrested. While the dynamics possesses features characteristic of nonergodic soft solids, including a relaxation time that grows linearly with the time since shear, comparison with behavior of quenched supercooled liquids indicates that this evolution is not directly related to traditional aging phenomena in glasses.

Percutaneous transvenous mitral commissurotomy in patients with severe mitral stenosis and acute rheumatic fever

There is a concern that percutaneous transvenous mitral commissurotomy (PTMC) performed during acute rheumatic fever (ARF) may result in adverse outcomes. We performed a retrospective study at a tertiary care center. Ten patients (ages 8-12 years) with severe symptomatic mitral stenosis and ARF who underwent PTMC (ARF group) were compared with 10 controls with similar mitral valve area (MVA). The procedure was successful in all patients. The median MVA increased from 0.7 to 1.5 cm2 following PTMC in the ARF group and from 0.7 to 1.8 cm2 in the control group [p = not significant (NS)]. The median MVA was 1.2 cm2 in the study group compared to 1.6 cm2 in the control group (p = 0.02) over a mean follow-up of 17.5 +/- 11.7 months. Echocardiographic restenosis occurred in 4 patients (40%) in the ARF group compared to 1 patient (10%) in the control group (p = NS). The improvement in the New York Heart Association functional class was maintained in 8 patients of the ARF group and 9 patients of the control group. PTMC can be performed in children with ARF without an increase in procedural complications. However, the restenosis rates appear to be higher.

Scattering for mixtures of hard spheres: comparison of total scattering intensities with model

The angular dependence of the intensity of x-rays scattered from binary and ternary hard sphere mixtures is investigated and compared to the predictions of two scattering models. Mixture ratio and total volume fraction dependent effects are investigated for size ratios equal to 0.51 and 0.22. Comparisons of model predictions with experimental results indicate the significant impact of the role of particle size distributions in interpreting the angular dependence of the scattering at wave vectors probing density fluctuations intermediate between the sizes of the particles in the mixture.

Clustering and mechanics in dense depletion and thermal gels

We report on the microstructure and mechanical properties (elastic modulus) of concentrated depletion and thermal gels of octadecyl-coated silica particles for different values of the strength of interaction--polymer concentration for depletion gels and temperature for thermal gels. The depletion gels are composed of dense clusters and voids, while the thermal gels are devoid of clusters. Shear breaks up clusters in depletion gels while it induces clustering in the thermal gels. In both of these gels, the microstructure recovers to the presheared state upon cessation of shear. The recovery of the elastic modulus mimics the microstructure in the sense that the elastic modulus recovers to the presheared sheared state after shearing is stopped. Calculations of the gel boundary by modeling the interactions with an effective one-component square-well model reveals that suspensions with similar ranges of attraction gel at the same volume fraction at a fixed strength of attraction. Calculations of the elastic modulus using the naïve mode coupling theory for depletion gels are in good agreement with experimental measurements provided clustering is taken into account and have the same magnitude as the elastic moduli of thermal gels with similar strengths of attraction. These calculations, in addition to the experimental observations reinforce the point that the microscopic parameter determining the elastic modulus of dense gels and its recovery is the localization length which is only a fraction of the particle diameter and not the structure on the length scale of the particle diameter and larger.

Angiogenesis in normal and neoplastic ovaries

Ovarian physiology is intricately connected to hormonally regulated angiogenic response. Recent advances in the post genomic revolution have significantly impacted our understanding of ovarian function. In an angiogenesis perspective, the ovary offers a unique opportunity to unravel the molecular orchestration of blood vessel development and regression under normal conditions. A majority of ovarian cancers develop from the single layer of epithelium surrounding the ovaries. Angiogenesis is critical for the development of ovarian cancer and its peritoneal dissemination. The present review summarizes recent findings on the angiogenic response in neoplastic ovaries and discusses the prospects of using anti-angiogenic approaches to treat ovarian cancer.

Intermediate-term results of percutaneous transvenous mitral commissurotomy in children less than 12 years of age

The objectives of this study were to review the efficacy of percutaneous transvenous mitral commissurotomy (PTMC) in young children less than 12 years of age and to provide intermediate-term follow-up data. There is a paucity of information regarding the long-term efficacy of PTMC done in children less than 12 years of age. The data of 100 consecutive children less than 12 years of age (mean, 11.1 +/- 1.2 years) who underwent PTMC using Inoue balloon were analyzed retrospectively. Serial clinical and echocardiographic follow-up information of more than 6 months was available in 94 patients. The procedure was successful in 94 patients. The mean calculated mitral valve area (MVA) increased from 0.72 0.14 to 1.7 0.35 cm(2) (P 0.0001). Echocardiographic restenosis (MVA < or = 1 cm(2) or > 50% gain loss) occurred in 14 of 94 patients (16%) over a mean follow-up of 34.4 25.9 (range, 2-115) months. The improvement in New York Heart Association (NYHA) functional class was maintained in most patients (from a mean of 2.87 0.5 pre-PTMC to 1.42 0.6 at follow-up). Seven out of 14 patients with restenosis underwent a re-PTMC. The actuarial rate of good functional status (survival, no repeat interventions, and NYHA class 1 or 2) at 100 months was 75.4% 8.7%. PTMC provides excellent intermediate-term palliation even in young children with rheumatic mitral stenosis.

Primary vitrectomy for combined rhegmatogenous retinal detachment and choroidal detachment with or without oral corticosteroids: a pilot study

PURPOSE

The occurrence of choroidal detachment (CD) in eyes with primary rhegmatogenous retinal detachment (RRD) is relatively uncommon (2%-4.5%). Recent reports suggest that primary vitrectomy yields better anatomic success than scleral buckling. However, for these inflamed eyes with low intraocular pressure, the influence of preoperative oral steroids on reattachment rates has not been elucidated yet.

METHODS

Twenty eyes with combined RRD and CD that underwent primary vitrectomy were randomized to receive oral steroids (for 1 week) or no oral steroids before surgery.

RESULTS

Preoperative clinical data such as mean age, lens status, Snellen visual acuity, duration of macular detachment, CD (size and extent), and retinal detachment characteristics (e.g., extent, number of retinal breaks, atrophic or tractional retinal break, size of retinal break, and location of retinal break) were similarly distributed in both groups. Single-operation anatomic success was 81.8% (9/11) among those patients who received preoperative oral steroids and was 66.7% (6/9) among those who did not receive preoperative oral steroids. After reoperation, anatomic success was 100% in both groups. The mean follow-up was 20.1 months.

CONCLUSION

The results suggest that administration of oral steroids before primary vitrectomy in eyes with combined RRD and CD improves reattachment rates.

Amino acids differentially regulate insulin receptor tyrosine kinase and phosphatidyl inositol-3-OH-kinase activities in human monocytes exposed to high glucose concentration

Chronic hyperglycemia and insulin resistance are the common factors involved in the development of vascular complications in diabetes mellitus (DM) patients. Since insulin signaling pathway has been shown to be regulated by nutritional supplements, in the present study, we investigated the possible effects of free amino acids, such as lysine, arginine and alanine and their mixture in modulating the insulin receptor tyrosine kinase (IRTK) and phosphatidyl inositol-3-OH-kinase (PI3K) activities and on the changes in actin dynamics in monocytes (MC), exposed to high glucose concentration (25 mM). IRTK and PI3K activities were markedly decreased in MC, incubated with 25 mM glucose. However, on treatment with amino acids, only lysine was effective in augmenting IRTK and PI3K activities in a dose-dependent manner. Arginine had marginal effect in promoting these activities. Equimolar mixture of amino acids showed marginal effect of augmenting only IRTK activity. Alanine had no effect. The F-actin filaments showed grossly diminished organization in the cells treated with 25 mM glucose alone, as assessed by specific binding to phalloidin-FITC, when compared with cells treated with 5 mM glucose. On the other hand, a significant improvement in the F-actin organization was observed in the cells co-incubated with 25 mM glucose and lysine. A possible molecular mechanism is the antiglycating effect of amino acids. The signal transduction starts with binding of ATP to lysine at position 1030 in the beta sub unit of the receptor. This lysine (1030) may be protected by the added lysine or to some extent arginine from glycation and loss of function. In summary, our findings suggest that the amino acids apart from their antiglycating property can also modulate/influence the activities of pivotal enzymes that are upstream in the insulin-mediated signal transduction pathway and bring down glucose.

Adeno-associated virus-mediated delivery of a mutant endostatin suppresses ovarian carcinoma growth in mice

Earlier studies have shown that a point mutation in human endostatin at position 125 (human endostatin wherein proline 125 was substituted with alanine, P125A-endostatin) improves endothelial cell binding and antiangiogenic activity. In the present study, we investigated the effect of recombinant adeno-associated virus (rAAV)-mediated gene delivery of P125A-endostatin (rAAV-P125Aendo) in a mouse model of ovarian carcinoma. Intramuscular (i.m.) injection of rAAV-P125Aendo resulted in a dose-dependent increase in serum endostatin levels. Consequently, vascular endothelial growth factor- and basic fibroblast growth factor-mediated angiogenesis was significantly inhibited in mice injected with rAAV-P125Aendo as compared to control mice injected with rAAV-LacZ. Furthermore, gene therapy using rAAV-P125Aendo construct showed sustained secretion of P125A-endostatin for up to 9 weeks after a single i.m. administration. Recombinant AAV-P125Aendo injection significantly inhibited the growth of human ovarian cancer cells in athymic nude mice. Immunofluorescence studies of residual tumors surgically removed from the rAAV-P125Aendo-treated animals showed decreased number of vessel ends and vessel length, indicating inhibition of angiogenesis. These studies suggest that recombinant AAV-mediated antiangiogenic gene therapy methods can be used to inhibit ovarian cancer growth.

Evidence of gap anisotropy in superconducting YNi2B2C using directional point-contact spectroscopy

We present a study of the anisotropy in the superconducting energy gap in a single crystal of YNi2B2C (T(c) approximately 14.6 K) using directional point-contact spectroscopy. The superconducting energy gap at 2.7 K, when measured for I||c, is 4.5 times larger than that for I||a. The energy gaps in the two directions also have different temperature dependences. Our results support a scenario with s + g like symmetry.