Template-free 3D titanium carbide (Ti3C2Tx) MXene particles crumpled by capillary forces.

Ti3C2Tx and other types of MXene nanosheets are an exciting new class of 2D materials. However, little has been reported on manipulating the shape of MXene nanosheets. Here, we demonstrate that flat Ti3C2Tx nanosheets encapsulated within spray-dried droplets can be scrolled, bent, and folded into 3D crumpled structures. This morphological change was observed to be reversible upon rehydration.

Protective Effects of Molsidomine Against Cisplatin-Induced Nephrotoxicity.

BACKGROUND: Cisplatin, an effective chemotherapeutic agent, is used for the treatment of several types of cancers. However, cisplatin has some severe side effects such as nephrotoxicity. On the other hand, molsidomine, a NO donor, has anti-oxidative and vasodilator effects. OBJECTIVES: The aim of this study was to estimate the protective effects of molsidomine on cisplatin-induced nephrotoxicity. MATERIAL AND METHODS: Thirty-two rats were randomly divided into 4 groups as follows: (1) control; (2) received a single-dose intraperitoneal (i.p.) injection of 5 mg/kg cisplatin; (3) received single i.p. dose of molsidomine (4 mg/kg/day) for 3 consecutive days before cisplatin treatment; (4) received single i.p. dose of molsidomine (4 mg/kg/day) for 3 consecutive days. The specific biochemical markers, including antioxidants, and the histopathological alterations were evaluated. RESULTS: Cisplatin significantly increased malondialdehyde (MDA) and myeloperoxidase (MPO) levels and decreased glutathione peroxidase (GPX) level. Molsidomine significantly decreased MPO level nearly to control level; however, its ameliorating effects on MDA, SOD, CAT and GPX did not reach to significant levels. Cisplatin-induced elevation of blood-urea-nitrogen and serum-creatinine were diminished after molsidomine administration. Cisplatin also induced severe tubular degeneration, nuclear condensation, apoptosis and scattered patchy inflammation in the histological examination. Molsidomine improved all of these histological damages. CONCLUSIONS: In this study, the beneficial effect of molsidomine against cisplatin nephrotoxicity has been evaluated for the first time.

Targeted colonic claudin-2 expression renders resistance to epithelial injury, induces immune suppression, and protects from colitis.

Expression of claudin-2, a tight junction protein, is highly upregulated during inflammatory bowel disease (IBD) and, due to its association with epithelial permeability, has been postulated to promote inflammation. Notably, claudin-2 has also been implicated in the regulation of intestinal epithelial proliferation. However, precise role of claudin-2 in regulating colonic homeostasis remains unclear. Here, we demonstrate, using Villin-Claudin-2 transgenic mice, that increased colonic claudin-2 expression augments mucosal permeability as well as colon and crypt length. Most notably, despite leaky colon, Cl-2TG mice were significantly protected against experimental colitis. Importantly, claudin-2 expression increased colonocyte proliferation and provided protection against colitis-induced colonocyte death in a PI-3Kinase/Bcl-2-dependent manner. However, Cl-2TG mice also demonstrated marked suppression of colitis-induced increases in immune activation and associated signaling, suggesting immune tolerance. Accordingly, colons from naive Cl-2TG mice harbored significantly increased numbers of regulatory (CD4(+)Foxp3(+)) T cells than WT littermates. Furthermore, macrophages isolated from Cl-2TG mouse colon exhibited immune anergy. Importantly, these immunosuppressive changes were associated with increased synthesis of the immunoregulatory cytokine TGF-ß by colonic epithelial cells in Cl-2TG mice compared with WT littermates. Taken together, our findings reveal a critical albeit complex role of claudin-2 in intestinal homeostasis by regulating epithelial permeability, inflammation and proliferation and suggest novel therapeutic opportunities.

Inhibition of Ras-GTPase farnesylation and the ubiquitin-proteasome system or treatment with angiotensin-(1-7) attenuates spinal cord injury-induced cardiac dysfunction.

Cardiovascular diseases are one of the principal causes of death and disability in people with spinal cord injury (SCI). The present study was designed to investigate if acute treatment with FPTIII (an inhibitor of Ras-GTPase farnesylation) or MG132 (an inhibitor of ubiquitin-proteasome pathway [UPS]) or administration of angiotensin-(1-7), also known as Ang-(1-7), (a known inhibitor of cardiac NF-kB) would be cardioprotective. The weight drop technique produced a consistent contusive injury of the spinal cord at the T13 segment. Hearts were isolated from rats either 6 months (SCI-6) or 12 months (SCI-12) after SCI. Hearts were perfused for 30 min and then subjected to 30 min ischemia followed by 30 min reperfusion (I/R). Recovery of cardiac function after I/R was measured as left ventricular developed pressure (P(max)) and coronary flow (CF). Drugs were given during perfusion before hearts were exposed to ischemia and reperfusion. Percent recovery (%R) in P(max) and CF in hearts from control animals were 48±6 and 50±5, respectively, whereas none of the hearts from animals with SCI recovered after 30 min of ischemia. Treatment with FPTIII, MG 132, or Ang-(1-7) before ischemia for 30 min led to significant recovery of heart function following ischemia in SCI-6 but not in SCI-12 animals. Thus we have shown that acute treatments with FPTIII, MG132, or Ang-(1-7) improve cardiac recovery following ischemic insult in animals with SCI and may represent novel therapeutic agents for preventing ischemia-induced cardiac dysfunction in patients with SCI.

Butyrylcholinesterase activity in gestational diabetes: correlation with lymphocyte subpopulations in peripheral blood.

PROBLEM: Inefficient clearance of pregnancy-threatening toxins may contribute to gestational diabetes (GD) and Type II diabetes mellitus (DM) through mechanisms involving immune dysregulation. METHOD OF STUDY: Peripheral venous blood from pregnant Kuwaiti women in third trimester, including 15 GD and 17 DM patients, 14 healthy pregnant (HP) and eight non-pregnant subjects, was analyzed by two-color flow cytometery for number and percentage representation of T lymphocytes. Buterylcholinesterase (BuChE) activity was measured using buterylthiocholine iodide and spectrophotometry. RESULTS: Relative to HP, GD patients exhibited higher ratios of activated and memory phenotypes, including CD4+ CD25+ (P < 0.01), CD4+ HLA-DR (P < 0.05) and CD4+ CD45RO+ (P < 0.05) cells. Serum BuChE activity exhibited positive correlation within the HP cohort with CD4+ CD25+ (P < 0.05), but not in GD and DM cohorts. CONCLUSIONS: Positive correlation between BuChE and a (presumptive) 'regulatory' T-cell phenotype in HP, but not GD or DM may indicate existence of protective detoxification mechanisms against oxidative stress in normal pregnancies.

Major lymphocyte populations and T-cell expression of ICAM-1 and L-selectin adhesion molecules in Kuwaitis with asthma and rhinitis.

The authors evaluate major immunologic features of asthma and allergies in a Kuwaiti population. They analyzed peripheral venous blood from 17 asthmatic and 17 healthy long-term residents of Kuwait by using two-color flow cytometry for major lymphocyte subpopulations; they also evaluated 10 healthy individuals who had recently arrived in Kuwait. Relative to healthy subjects, asthmatics exhibited increased percentages of T+ NK cells (p < .01), T-helper cells (p < .05), T-cytotoxic and NK cells for both total numbers (p < .01-.001) and percentages (p < .05-.01), and increased percentages of T cells expressing CD54 (ICAM-1; p < .001) and CD62 (L-selectin; p < .01). However, B cells were present at significantly lower levels in asthmatics, both in total numbers (p < .05) and percentages (p < .01). In comparison with healthy individuals who had recently arrived in Kuwait, healthy long-term residents exhibited elevated numbers of pan-T cells (p < .01) and T-helper cells (p < .05). These results help establish immunological parameters for asthma and allergies in Kuwaiti populations.

In vitro effects of astaxanthin combined with ginkgolide B on T lymphocyte activation in peripheral blood mononuclear cells from asthmatic subjects.

This study was undertaken to identify novel approaches to pharmacological treatment of asthma. Here we hypothesize that the platelet-activating factor receptor antagonist ginkgolide B (GB) in combination with the antioxidant carotenoid astaxanthin (ASX) suppresses T cell activation comparably to two commonly-used antihistamines: cetirizine dihydrochloride (CTZ) and azelastine (AZE). Peripheral blood mononuclear cells from asthmatics, cultured 24 h with either 50 microg/ml phytohemaglutinin (PHA) or PHA plus selected dosages of each drug are analyzed by flow cytometry for CD25+ or HLA-DR+ on CD3+ (T cells). Results are reported as stimulation indices (SI) of %CD3+CD25+ cells or %CD3+HLA-DR+ cells in cultures treated with PHA alone versus these subpopulations in cultures treated with both PHA and drugs. Combinations of ASX and GB exhibited optimal suppression at 10(-7) M GB + 10(-8) M ASX for CD3+CD25+ (SI = 0.79 +/- 0.04, P = 0.001) and 10(-7) M GB + 10(-7) M ASX for CD3+HLA-DR+ (SI = 0.82 +/- 0.05, P = 0.004). In conclusion, suppression of T cell activation below fully stimulated values by GB, ASX, and their combinations was comparable and for some combinations better than that mediated by CTZ and AZE. These results suggest that ASX and GB may have application as novel antiasthmatic formulations.

Vascular stroma-derived endothelial colony forming progenitor cells adapt to tumour growth.

Under appropriate nutrient agar culture conditions, primary or xenografted human and animal tumour biopsy-derived cell suspensions will form two types of colony. The first type, consisting of tight colonies of round cells which form tumours when introduced into nude mice, is of neoplastic origin. The second type of colony, the cells of which fail to form tumours on injection into nude mice, consists of loose colonies of larger, inter-connecting elongated bi- or tripolar cells and is thought to originate from vascular stroma-derived endothelial colony forming progenitor cells (V-ECPC). The likely importance of V-ECPC to tumour growth is emphasised by a positive correlation between the VECPC-derived endothelial cell colonies and both tumour vascularity and growth rate. A high cloning efficiency obtained from tumours of particularly intense vascular nature indicates that this cell is of importance in vascular adaptation and therefore tumour growth. In contrast, avascular, fibrotic tumour tissue yielded very low numbers of stromal vascular endothelial cell colonies. The results suggest that stromal vascular endothelial cell colonies do not arise from the mature fibroblastic elements of the tumour stroma, but rather from cells within actively growing regions. Tritiated thymidine uptake studies show that the vascular stroma-derived endothelial colony forming progenitor cells cell are cycling. Cell separation studies have characterized the as yet morphologically unidentified V-ECPC as having a sedimentation rate of 4.7 mm./hr and a mean density of 1.068 g/cm3 and hence a calculated volume of 450 microns 3.

Antioxidant enzyme level in the testes of cirrhotic rats.

OBJECTIVES: An understanding of the tissue and organ level of antioxidant enzymes that scavenge reactive oxygen species may provide an indication of their susceptibility to free radical-related cytotoxic damage. A direct association between testicular production of excessive reactive oxygen species and male infertility has been noted. We measured the activities of superoxide dismutase and glutathione peroxidase in the testes of thioacetamide-induced cirrhotic rats. METHODS: Antioxidant enzyme activities and trace element levels (copper, zinc, manganese, and selenium) in the testes of thioacetamide-induced cirrhotic and control rats were measured. The statistical difference between the experimental and control groups with regard to the activities of superoxide dismutase and glutathione peroxidase and levels of trace elements was analyzed with Student's t test. RESULTS: Our results showed a significant decrease in the activity of these enzymes in the testes of cirrhotic rats. The testicular levels of copper, zinc, and manganese, which are associated with these antioxidant enzymes, increased, whereas selenium decreased slightly in cirrhotic rats; that decrease was not statistically significant. CONCLUSIONS: Our studies showed a drastic decrease in the level of antioxidant enzymes in the testes of cirrhotic rats that could have deleterious effects on sperm function in these animals. Further studies are necessary to understand the exact pathways of trace element metabolism in the testes of cirrhotic rats.

Thrombopoietin induces phosphoinositol 3-kinase activation through SHP2, Gab, and insulin receptor substrate proteins in BAF3 cells and primary murine megakaryocytes.

Thrombopoietin (TPO) is a recently characterized member of the hematopoietic growth factor family that serves as the primary regulator of megakaryocyte (MK) and platelet production. The hormone acts by binding to the Mpl receptor, the product of the cellular proto-oncogene c-mpl. Although many downstream signaling targets of TPO have been identified in cell lines, primary MKs, and platelets, the molecular mechanism(s) by which many of these molecules are activated remains uncertain. In this report we demonstrate that the TPO-induced activation of phosphoinositol 3-kinase (PI3K), a signaling intermediate vital for cellular survival and proliferation, occurs through its association with inducible signaling complexes in both BaF3 cells engineered to express Mpl (BaF3/Mpl) and in primary murine MKs. Although a direct association between PI3K and Mpl could not be demonstrated, we found that several proteins, including SHP2, Gab2, and IRS2, undergo phosphorylation and association in BaF3/Mpl cells in response to TPO stimulation, complexes that recruit and enhance the enzymatic activity of PI3K. To verify the physiological relevance of the complex, SHP2-Gab2 association was disrupted by overexpressing a dominant negative SHP2 construct. TPO-induced Akt phosphorylation was significantly decreased in transfected cells suggesting an important role of SHP2 in the complex to enhance PI3K activity. In primary murine MKs, TPO also induced phosphorylation of SHP2, its association with p85 and enhanced PI3K activity, but in contrast to the results in cell lines, neither Gab2 nor IRS2 are phosphorylated in MKs. Instead, a 100-kDa tyrosine-phosphorylated protein (pp100) co-immunoprecipitated with the regulatory subunit of PI3K. These findings support a model where PI3K activity is dependent on its recruitment into TPO-induced multiphosphoprotein complexes, implicate the existence of a scaffolding protein in primary MKs distinct from the known Gab and IRS proteins, and suggest that, in contrast to erythroid progenitor cells that employ Gab1 in PI3K signaling complexes, utilization of an alternate member of the Gab/IRS family could be responsible for specificity in TPO signaling.

Acute and chronic angiotensin-1 receptor antagonism reverses endothelial dysfunction in atherosclerosis.

BACKGROUND: The renin-angiotensin system may contribute to atherogenesis through the promotion of endothelial dysfunction. The present study was performed to determine whether angiotensin-1 (AT(1)) receptor inhibition improves endothelial dysfunction. METHODS AND RESULTS: In the femoral circulation of 19 patients with atherosclerosis and of 9 control subjects, we studied microvascular responses to reactive hyperemia, angiotensin II, acetylcholine, and sodium nitroprusside before and after the administration of intra-arterial losartan (10 mg). Femoral artery flow velocity was measured with a Doppler flow wire, and the femoral vascular resistance index (FVRI) was calculated as mean arterial pressure divided by flow velocity. Losartan induced a minor (5.9+/-2%, P=0. 02) reduction in FVRI and inhibited angiotensin II-mediated vasoconstriction in both patient groups (P<0.01). After the administration of losartan, acetylcholine-mediated vasodilation was augmented in patients (44+/-5% to 58+/-4% reduction in FVRI with infusion at a rate of 150 microgram/min, P<0.001) but not control subjects. Vasodilation during reactive hyperemia was also greater after AT(1) receptor inhibition (P=0.03) in patients, but the response to sodium nitroprusside remained unchanged. In a separate group of 31 patients with atherosclerosis, we investigated the effect of 8 weeks of oral losartan therapy on brachial artery flow-mediated vasodilation with the use of high-resolution ultrasound. Oral losartan therapy improved flow-mediated brachial artery dilation (1.4+/-0.9% to 3.2+/-0.8%, P=0.03) but had no effect on the nitroglycerin response. Serum nitrogen oxide levels increased from 21.6+/-1.7 to 26.7+/-2.4 micromol/L (P=0.008). CONCLUSIONS: The results of the present study indicate that inhibition of the AT(1) receptor in patients with atherosclerosis reverses endothelial dysfunction by improving NO availability and therefore may have long-term therapeutic benefits.

Growth factors and insulin stimulate tyrosine phosphorylation of the 51C/SHIP2 protein.

Antibodies raised against the 51C/SHIP2 inositol polyphosphate 5'-phosphatase were used to examine the effects of growth factors and insulin on the metabolism of this protein. Immunoblot analysis revealed that the 51C/SHIP2 protein was widely expressed in fibroblast and nonhematopoietic tumor cell lines, unlike the SHIP protein, which was found only in cell lines of hematopoietic origin. The 51C/SHIP2 antiserum precipitated a protein of approximately 145 kDa along with an activity which hydrolyzed phosphatidylinositol 3,4, 5-trisphosphate to phosphatidylinositol 3,4-bisphosphate. Tyrosine phosphorylation of the 51C/SHIP2 protein occurred in response to treatment of cells with epidermal growth (EGF), platelet-derived growth factor (PDGF), nerve growth factor (NGF), insulin-like growth factor-1 (IGF-1), or insulin. EGF and PDGF induced transient tyrosine phosphorylation of 51C/SHIP2, with maximal tyrosine phosphorylation occurring at 5-10 min following treatment and returning to near basal levels within 20 min. In contrast, treatment of cells with NGF, IGF-1, or insulin resulted in prolonged tyrosine phosphorylation of 51C/SHIP2 protein, with 40-80% maximal phosphorylation sustained for up to 2 h following agonist treatment. The kinetics of activation of the Akt/PKB protein kinase by the various factors correlated well with the kinetics of tyrosine phosphorylation of 51C/SHIP2. EGF, NGF, and PDGF stimulated the association of 51C/SHIP2 protein with the Shc adapter protein; however, no Shc could be detected in 51C/SHIP2-immune precipitates from cells treated with IGF-1 or insulin. The data suggest that 51C/SHIP2 may play a significant role in regulation of phosphatidylinositol 3'-kinase signaling by growth factors and insulin.

A controlled study of the effects of EEG biofeedback on cognition and behavior of children with attention deficit disorder and learning disabilities.

Eighteen children with ADD/ADHD, some of whom were also LD, ranging in ages from 5 through 15 were randomly assigned to one of two conditions. The experimental condition consisted of 40 45-minute sessions of training in enhancing beta activity and suppressing theta activity, spaced over 6 months. The control condition, waiting list group, received no EEG biofeedback. No other psychological treatment or medication was administered to any subjects. All subjects were measured at pretreatment and at posttreatment on an IQ test and parent behavior rating scales for inattention, hyperactivity, and aggressive/defiant (oppositional) behaviors. At posttreatment the experimental group demonstrated a significant increase (mean of 9 points) on the K-Bit IQ Composite as compared to the control group (p <.05). The experimental group also significantly reduced inattentive behaviors as rated by parents (p < .05). The significant improvements in intellectual functioning and attentive behaviors might be explained as a result of the attentional enhancement affected by EEG biofeedback training. Further research utilizing improved data collection and analysis, more stringent control groups, and larger sample sizes are needed to support and replicate these findings.

A direct interaction between G-protein beta gamma subunits and the Raf-1 protein kinase.

Raf-1 is a serine/threonine protein kinase positioned downstream of Ras in the mitogen-activated protein kinase cascade. Using a yeast two-hybrid strategy to identify other proteins that interact with and potentially regulate Raf-1, we isolated a clone encoding the carboxyl-terminal half of the G beta 2 subunit of heterotrimeric G-proteins. In vitro, purified G beta gamma subunits specifically bound to a GST fusion protein encoding amino acids 1-330 of Raf-1 (Raf/330). Binding assays with truncation mutants of GST-Raf indicate that the region located between amino acids 136 and 239 is a primary determinant for interaction with G beta gamma. In competition experiments, the carboxyl terminus of beta-adrenergic receptor kinase (beta ARK) blocked the binding of G beta gamma to Raf/330; however, the Raf-1-binding proteins, Ras and 14-3-3, had no effect. Scatchard analysis of in vitro binding between Raf/330 and G beta gamma revealed an affinity of interaction (Kd = 163 +/- 36 nM), similar to that seen between G beta gamma and beta ARK (Kd = 87 +/- 24 nM). The formation of native heterotrimeric G alpha beta gamma complexes, as measured by pertussis toxin ADP-ribosylation of G alpha, could be disrupted by increasing amounts of Raf/330, with an EC50 of approximately 200 nM, in close agreement with the estimated binding affinity. In vivo complexes of Raf-1 and G beta gamma were isolated from human embryonic kidney 293-T cells transfected with epitope-tagged G beta 2. The identification and characterization of this novel interaction raises several possibilities for signaling cross-talk between growth factor receptors and those receptors coupled to heterotrimeric G-proteins.

Activators of protein kinase C stimulate association of Shc and the PEST tyrosine phosphatase.

Using the yeast two-hybrid system, complementary DNA clones were isolated from a HeLa cell library encoding proteins that interacted with p52shc. One of these clones encoded the non-catalytic, COOH-terminal half of the cytosolic protein tyrosine phosphatase PTP-PEST. Expression of truncated forms of p52shc in the two-hybrid system revealed that the amino-terminal half of p52shc was sufficient for interaction with PTP-PEST. The p52 and p66 forms of Shc, but not the p46 form, bound to a glutathione S-transferase fusion protein containing the region of PTP-PEST isolated from the two-hybrid screen. Similarly, when HeLa cell lysates were immunoprecipitated with PTP-PEST antiserum, p52shc and p66shc proteins, but not p46shc, co-precipitated. Shc-PTP-PEST complex formation was stimulated 6-8-fold by the protein kinase C activator phorbol 12-myristate 13-acetate, while epidermal growth factor and serum had no effect. Phorbol 12-myristate 13-acetate also stimulated phosphorylation of p52shc and p66shc. The muscarinic agonist carbachol (also an activator of protein kinase C) stimulated complex formation 3-5-fold in SH-SY5Y neuroblastoma cells. These results suggest a role for PTP-PEST in G protein receptor signaling and in cross-talk between G protein receptor and tyrosine kinase receptor pathways.

Epidermal growth factor (EGF)-stimulated tyrosine phosphorylation and EGF receptor degradation in cells expressing EGF receptors truncated at residue 973.

Epidermal growth factor (EGF)-stimulated tyrosine phosphorylation of proteins was examined in cells expressing wild-type (WT-EGFR) EGF receptors or EGF receptors truncated at residue 973 (973-EGFR). A much broader spectrum of tyrosine phosphorylated proteins was found following EGF treatment of 973-EGFR expressing cells compared with cells expressing wild-type receptors. Several additional ras GTPase activating protein-associated tyrosine phosphorylated proteins were found in EGF-treated 973-EGFR cells relative to WT-EGFR cells. Additional tyrosine-phosphorylated proteins were also found to co-immunoprecipitate with phospholipase C gamma 1 (PLC gamma 1) following EGF treatment of cells expressing 973-EGFR relative to cells expressing WT-EGFR. EGF-stimulated tyrosine phosphorylation of PLC gamma 1 was found in cells expressing WT-EGFR, but not in cells expressing 973-EGFR. WT-EGF receptor from EGF-treated cells bound well to bacterially expressed src homology (SH) regions of PLC gamma 1 and to a lesser extent to bacterially expressed GTPase activating protein SH regions. No binding of 973-EGF receptor to SH regions of either protein could be detected. EGF treatment greatly reduced the half-life of WT-EGFR, but had relatively little effect on the half-life of 973-EGFR. EGF induced internalization of 973-EGFR at a slower rate than WT-EGFR and caused the appearance of discrete receptor degradation products for both cell types. The data indicate that truncation of the EGF receptor at residue 973 alters receptor substrate specificity, decreases the rate of receptor internalization, and has an inhibitory effect on receptor degradation.

Comparison of two coronary prognostic indices.

Two coronary prognostic indices for patients treated in a coronary care unit, namely the Norris Index and the Chapman-Gray Index were compared. Both were found to be reliable but the Chapman-Gray Index with its ready reckoner was more convenient and was subject to fewer subjective data.